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Sample records for repelling blood feeding

  1. Effect of the Topical Repellent para-Menthane-3,8-diol on Blood Feeding Behavior and Fecundity of the Dengue Virus Vector Aedes aegypti

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    Jugyeong Lee

    2018-06-01

    Full Text Available Dengue fever is an acute disease caused by the dengue virus and transmitted primarily by the mosquito Aedes aegypti. The current strategy for dengue prevention is vector control including the use of topical repellents to reduce mosquito biting. Although N,N-diethyl-m-methylbenzamide (DEET is the most common active ingredient in topical repellent products, para-menthane-3,8-diol (PMD is also used commercially. Studies have indicated PMD reduced biting by 90–95% for up to 6–8 h, similar to the efficacy of DEET, depending on the testing environment. The purpose of this study was to evaluate the behavioral effects of PMD on Ae. aegypti blood feeding and fecundity to explore the potential impact of PMD on downstream mosquito life-history traits. Two experiments were performed. In both experiments, cohorts of female Ae. aegypti (Belize strain were exposed to 20% PMD or ethanol for 10 min in a closed system and introduced to an artificial membrane feeding system. Following a 30min feed time, mosquitoes of Experiment 1 were killed and weighed as a proxy measure of blood meal, whereas mosquitoes of Experiment 2 were monitored for oviposition, a measure of fecundity. Results showed a statistically significant reduction (p < 0.001 in the percentage of Ae. aegypti that blood-fed when exposed to PMD (38% compared to those non-exposed (49%. No significant difference in fecundity between test populations was indicated. These findings suggest that exposure of Ae. aegypti to 20% PMD may influence the probability of subsequent blood feeding but of those mosquitoes that do blood feed, egg-lay density is not affected. Further studies are warranted to investigate the full range of effects of PMD exposure on other Ae. aegypti life-history traits such as mating, to continue characterizing the potential effects of PMD to impact overall vector population dynamics.

  2. Defensive Metabolites from Antarctic Invertebrates: Does Energetic Content Interfere with Feeding Repellence?

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    Laura Núñez-Pons

    2014-06-01

    Full Text Available Many bioactive products from benthic invertebrates mediating ecological interactions have proved to reduce predation, but their mechanisms of action, and their molecular identities, are usually unknown. It was suggested, yet scarcely investigated, that nutritional quality interferes with defensive metabolites. This means that antifeedants would be less effective when combined with energetically rich prey, and that higher amounts of defensive compounds would be needed for predator avoidance. We evaluated the effects of five types of repellents obtained from Antarctic invertebrates, in combination with diets of different energetic values. The compounds came from soft corals, ascidians and hexactinellid sponges; they included wax esters, alkaloids, a meroterpenoid, a steroid, and the recently described organic acid, glassponsine. Feeding repellency was tested through preference assays by preparing diets (alginate pearls combining different energetic content and inorganic material. Experimental diets contained various concentrations of each repellent product, and were offered along with control compound-free pearls, to the Antarctic omnivore amphipod Cheirimedon femoratus. Meridianin alkaloids were the most active repellents, and wax esters were the least active when combined with foods of distinct energetic content. Our data show that levels of repellency vary for each compound, and that they perform differently when mixed with distinct assay foods. The natural products that interacted the most with energetic content were those occurring in nature at higher concentrations. The bioactivity of the remaining metabolites tested was found to depend on a threshold concentration, enough to elicit feeding repellence, independently from nutritional quality.

  3. Defensive Metabolites from Antarctic Invertebrates: Does Energetic Content Interfere with Feeding Repellence?

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    Núñez-Pons, Laura; Avila, Conxita

    2014-01-01

    Many bioactive products from benthic invertebrates mediating ecological interactions have proved to reduce predation, but their mechanisms of action, and their molecular identities, are usually unknown. It was suggested, yet scarcely investigated, that nutritional quality interferes with defensive metabolites. This means that antifeedants would be less effective when combined with energetically rich prey, and that higher amounts of defensive compounds would be needed for predator avoidance. We evaluated the effects of five types of repellents obtained from Antarctic invertebrates, in combination with diets of different energetic values. The compounds came from soft corals, ascidians and hexactinellid sponges; they included wax esters, alkaloids, a meroterpenoid, a steroid, and the recently described organic acid, glassponsine. Feeding repellency was tested through preference assays by preparing diets (alginate pearls) combining different energetic content and inorganic material. Experimental diets contained various concentrations of each repellent product, and were offered along with control compound-free pearls, to the Antarctic omnivore amphipod Cheirimedon femoratus. Meridianin alkaloids were the most active repellents, and wax esters were the least active when combined with foods of distinct energetic content. Our data show that levels of repellency vary for each compound, and that they perform differently when mixed with distinct assay foods. The natural products that interacted the most with energetic content were those occurring in nature at higher concentrations. The bioactivity of the remaining metabolites tested was found to depend on a threshold concentration, enough to elicit feeding repellence, independently from nutritional quality. PMID:24962273

  4. Repellent and deterrent effects of SS220, Picaridin, and Deet suppress human blood feeding by Aedes aegypti, Anopheles stephensi, and Phlebotomus papatasi.

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    Klun, Jerome A; Khrimian, Ashot; Debboun, Mustapha

    2006-01-01

    A series of behavioral tests with Aedes aegypti (L.), Anopheles stephensi Liston, mosquitoes, and the sand fly Phlebotomus papatasi Scopoli in the presence of Deet, SS220, and Picaridin topically applied to the skin of human volunteers showed that the insects were deterred from feeding on and repelled from surfaces emanating the compounds. When offered a 12- or 24-cm2 area of skin, one-half treated with compound and one-half untreated, the insects fed almost exclusively on untreated skin. The sand flies and mosquitoes did not at any time physically contact chemically treated surfaces. When treated and untreated skin areas were covered with cloth, insects contacted, landed, and bit only through cloth covering untreated skin. These observations provided evidence that the compounds deterred feeding and repelled insects from treated surfaces primarily as a result of olfactory sensing. When cloth, one-half untreated and one-half treated with chemical, was placed over untreated skin, insects only touched and specifically bit through the untreated cloth. This showed that the activity of the chemicals does not involve a chemical x skin interaction. In the presence of any of the three chemicals, no matter how they were presented to the insects, overall population biting activity was reduced by about one-half relative to controls. This reduction showed a true repellent effect for the compounds. Results clearly showed that Deet, SS220, and Picaridin exert repellent and deterrent effects upon the behavior of mosquitoes and sand flies. Heretofore, the combined behavioral effects of these compounds upon mosquito and sand fly behavior were unknown. Moreover, protection afforded by Deet, SS220, and Picaridin against the feeding of these three disease vectors on humans is mechanistically a consequence of the two chemical effects.

  5. Microsporidiosis (Microsporidia: Culicosporidae) alters blood-feeding responses and DEET repellency in Aedes aegypti (Diptera: Culicidae).

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    Barnard, Donald R; Xue, Rui-De; Rotstein, Margaret A; Becnel, James J

    2007-11-01

    Infection of Aedes aegypti (L.) (Diptera: Culicidae) with Edhazardia aedis (Microsporidia: Culicosporidae) reduced mean human host attraction and landing/probing rates in female mosquitoes by 53 and 62%, respectively, compared with rates in microsporidia-free females. Infection with E. aedis reduced the average weight of unfed female mosquitoes by 4%, caused them to imbibe 23% less blood, and to lay 30% fewer eggs than healthy females. In contrast, E. aedis-infected mosquitoes required 20% more time (>1 h) than healthy females to bite skin treated with 15% DEET. Statistically significant morbidity in E. aedis-infected females was indicated by reductions in host attraction and landing/probing responses, the mass of unfed and blood-engorged females, and fecundity, and by increased DEET repellency.

  6. Effects of in vivo exposure to DEET on blood feeding behavior and fecundity in Anopheles quadrimaculatus (Diptera: Culicidae).

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    Xue, Rui-De; Ali, Arshad; Barnard, Donald R

    2007-07-01

    This study determined the effects of contact with DEET on guinea pig skin on mortality, probing time, blood feeding rate, engorgement time, and fecundity responses in female Anopheles quadrimaculatus Say. Exposure, in this manner, to 10% DEET (in ethanol) for 5 min, resulted in 98% mortality in mosquitoes after 24h. The median probing time (PT(50)) required by females, when exposed to 0.1%, 1.0%, and 10% DEET, was significantly (Pblood feeding rates in populations of females exposed to 1.0% DEET for feeding on the control guinea pigs (105.9s). The mean number of mature oöcytes per female (fecundity) in treatment (1.0% DEET) and control mosquitoes was not significantly different. The responses to DEET observed in this study suggest that repeated exposure of female A. quadrimaculatus populations to this repellent, in laboratory bioassays, could result in confounding of toxicant and repellent effects and inaccurate estimates of DEET repellency.

  7. Effects of Fatty Acid and Geraniol Repellent-Oil Mixtures Applied to Cattle on Blood Feeding and Reproductive Parameters in Field Populations of Haematobia irritans (Diptera: Muscidae).

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    Mullens, Bradley A; Soto, Diane; Gerry, Alec C; Fowler, Fallon E; Diniz, Alesha N

    2018-02-28

    California pastured cattle were treated with 250 ml of a 15% mixture of fatty acids (C8-C9-C10) or 125 ml of 2% geraniol in a mineral oil carrier to assess impacts on horn flies, Haematobia irritans (L.) (Diptera: Muscidae) over two summers. Horn flies were netted from cattle every 3-4 d for 2 wk before treatment, 2 wk during treatment (four treatments, with flies collected before each treatment), and 2 wk after treatments ceased. Blood meal weights were estimated by hemoglobin assay of excised abdomens. Other females were dissected to determine the number of active ovarioles and the stage of primary follicle development. Depending on year and herd, pretreatment males contained an average of 0.6-1.0 mg of blood, while females contained 1.7-2.7 mg. Pretreatment egg development (least developed oocytes were stage 1 and fully developed eggs were stage 5) averaged 3.7-4.3, and number of active ovarioles averaged 18.1 to 19.6/female. During treatment periods, significant reductions in blood weight were noted for females, but usually not for males, and females also often exhibited reduced mean oocyte stage and number of active ovarioles. Peaks in proportions of young nulliparous females (oocyte stages 1 or 2) were seen during some repellent application periods. This suggested older females had been killed or driven off from the local population by the treatments, and flies on cattle included more young flies that likely were recent arrivals. The repellent-oil mixture thus impacted blood feeding, reproductive fitness, and probably age structure in the field.

  8. Host-seeking and blood-feeding behavior of Aedes albopictus (Diptera: Culicidae) exposed to vapors of geraniol, citral, citronellal, eugenol, or anisaldehyde.

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    Hao, Huiling; Wei, Jianrong; Dai, Jianqing; Du, Jiawei

    2008-05-01

    The changes of the host-seeking and blood-feeding behavior of Aedes albopictus (Skuse) (Diptera: Culicidae) surviving in a space containing vapors of the spatial repellents geraniol, eugenol, citral, anisaldehyde, or citronellal were evaluated using an arm-in-cage test and a bioassay of bloodmeals on a shaved mouse. The mosquitoes surviving concentrations of geraniol, citral, eugenol, or anisaldehyde at 0.013, 0.025, 0.050, 0.100, and 0.250 microg/cm3 for 24 and 48 h all showed different degrees of reduction in host-seeking ability. After 48 h of exposure to 0.250 microg/cm3 geraniol, almost 100% of the mosquitoes lost their host-seeking ability. The next most potent spatial repellent, anisaldehyde, stopped host seeking by > 85.5%. Citronellal did not result in a significant reduction in the host-seeking ability at any concentration level after either 24 or 48 h of treatment. We also found that reduction of host-seeking ability recovered after various times. The longest recovery time (144 h) was observed for geraniol after 24 h at 0.250 microg/cm3. In the study, geraniol, eugenol, and citral all significantly affected the activation and orientation stages of the blood-feeding behavior. However, only anisaldehyde significantly interrupted the normal blood-feeding of mosquitoes in all stages of behavior. These initial laboratory results clearly showed that anisaldehyde and geraniol could be promising spatial repellents against Ae. albopictus that they could play a major role in new repellent technology.

  9. Sindbis virus infection alters blood feeding responses and DEET repellency in Aedes aegypti (Diptera: Culicidae).

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    Qualls, Whitney A; Day, Jonathan F; Xue, Rui-De; Bowers, Doria F

    2012-03-01

    Aedes aegypti (L.) (Diptera: Culicidae) female mosquitoes infected systemically with Sindbis virus (SINV) took longer than uninfected mosquitoes to locate and fully engorge on blood. On days 7 and 14 postexposure, blood feeding took 1.3 and 1.5 times longer in mosquitoes with a disseminated SINV infection, respectively. SINV dissemination did not affect the average weight of unfed Ae. aegypti, but did result in a 10 and 12% increase in blood imbibed compared with mosquitoes without a positive SINV dissemination and non-SINV-exposed mosquitoes, respectively. Ae. aegypti mosquitoes with a disseminated SINV infection fed an average of 4 h sooner than uninfected mosquitoes when offered a bloodmeal contained inside a DEET (N,N-diethyl-3-methylbenzamide) saturated (30%) bovine sausage casing. Together, these results indicate that behavioral changes in mosquito host-seeking, blood feeding and sensitivity to DEET occurred in mosquitoes after SINV infection and dissemination.

  10. Evaluation of a Noncontact, Alternative Mosquito Repellent Assay System.

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    Tisgratog, Rungarun; Kongmee, Monthathip; Sanguanpong, Unchalee; Prabaripai, Atchariya; Bangs, Michael J; Chareonviriyaphap, Theeraphap

    2016-09-01

    A novel noncontact repellency assay system (NCRAS) was designed and evaluated as a possible alternative method for testing compounds that repel or inhibit mosquitoes from blood feeding. Deet and Aedes aegypti were used in a controlled laboratory setting. Using 2 study designs, a highly significant difference were seen between deet-treated and untreated skin placed behind the protective screens, indicating that deet was detected and was acting as a deterrence to mosquito landing and probing behavior. However, a 2nd study showed significant differences between protected (behind a metal screen barrier) and unprotected (exposed) deet-treated forearms, indicating the screen mesh might restrict the detection of deet and thus influences landing/biting response. These findings indicate the prototype NCRAS shows good promise but requires further evaluation and possible modification in design and testing protocol to achieve more desirable operational attributes in comparison with direct skin-contact repellency mosquito assays.

  11. The repellency of lemongrass oil against stable flies, tested using video tracking

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    Baldacchino, Frédéric; Tramut, Coline; Salem, Ali; Liénard, Emmanuel; Delétré, Emilie; Franc, Michel; Martin, Thibaud; Duvallet, Gérard; Jay-Robert, Pierre

    2013-01-01

    Lemongrass oil (Cymbopogon citratus) is an effective repellent against mosquitoes (Diptera: Culicidae) and house flies (Diptera: Muscidae). In this study, its effectiveness was assessed on stable flies (Diptera: Muscidae) in laboratory conditions. First, we demonstrated that lemongrass oil is an active substance for antennal olfactory receptor cells of Stomoxys calcitrans as indicated by a significant increase in the electroantennogram responses to increasing doses of lemongrass oil. Feeding-choice tests in a flight cage with stable flies having access to two blood-soaked sanitary pads, one of which was treated with lemongrass oil, showed that stable flies (n = 24) spent significantly more time in the untreated zone (median value = 218.4 s) than in the treated zone (median value = 63.7 s). No stable flies fed on the treated pad, whereas nine fed on the untreated pad. These results suggest that lemongrass oil could be used as an effective repellent against stable flies. Additional studies to confirm its spatial repellent and feeding deterrent effects are warranted. PMID:23759542

  12. The mode of action of spatial repellents and their impact on vectorial capacity of Anopheles gambiae sensu stricto.

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    Ogoma, Sheila B; Ngonyani, Hassan; Simfukwe, Emmanuel T; Mseka, Antony; Moore, Jason; Maia, Marta F; Moore, Sarah J; Lorenz, Lena M

    2014-01-01

    Malaria vector control relies on toxicity of insecticides used in long lasting insecticide treated nets and indoor residual spraying. This is despite evidence that sub-lethal insecticides reduce human-vector contact and malaria transmission. The impact of sub-lethal insecticides on host seeking and blood feeding of mosquitoes was measured. Taxis boxes distinguished between repellency and attraction inhibition of mosquitoes by measuring response of mosquitoes towards or away from Transfluthrin coils and humans. Protective effective distance of coils and long-term effects on blood feeding were measured in the semi-field tunnel and in a Peet Grady chamber. Laboratory reared pyrethroid susceptible Anopheles gambiae sensu stricto mosquitoes were used. In the taxis boxes, a higher proportion of mosquitoes (67%-82%) were activated and flew towards the human in the presence of Transfluthrin coils. Coils did not hinder attraction of mosquitoes to the human. In the semi-field Tunnel, coils placed 0.3 m from the human reduced feeding by 86% (95% CI [0.66; 0.95]) when used as a "bubble" compared to 65% (95% CI [0.51; 0.76]) when used as a "point source". Mosquitoes exposed to coils inside a Peet Grady chamber were delayed from feeding normally for 12 hours but there was no effect on free flying and caged mosquitoes exposed in the semi-field tunnel. These findings indicate that airborne pyrethroids minimize human-vector contact through reduced and delayed blood feeding. This information is useful for the development of target product profiles of spatial repellent products that can be used to complement mainstream malaria vector control tools.

  13. Effects of Preexposure to DEET on the Downstream Blood-Feeding Behaviors of Aedes aegypti (Diptera: Culicidae) Mosquitoes.

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    Sugiharto, Victor A; Grieco, John P; Murphy, Jittawadee R; Olsen, Cara H; Colacicco-Mayhugh, Michelle G; Stewart, V Ann; Achee, Nicole L; Turell, Michael J

    2016-06-10

    Mosquito behavior is heavily influenced by the chemical molecules in the environment. This knowledge can be used to modify insect behaviors; particularly to reduce vector-host contact as a powerful method for disease prevention. N,N-Diethyl-meta-toluamide (DEET) is the most widely used insect repellent in the market and an excellent example of a chemical that has been used to modify insect behavior for disease prevention. However, genetic insensitivity and habituation in Aedes aegypti (L.) mosquitoes after preexposure to DEET have been reported. In this study, we investigated the effect of preexposure to DEET on the downstream blood-feeding behavior of Ae. aegypti mosquitoes and the duration of the effect. We exposed mosquitoes to four different DEET concentrations: 0.10, 0.12, 0.14, and 0.16% for 10 min then allowed the mosquitoes to blood-feed on an artificial blood-feeding system either immediately or after being held for 1, 3, 6, or 24 h following DEET exposure. We found that preexposing Ae. aegypti mosquitoes to 0.14 or 0.16% DEET lowered their blood engorgement level, but did not alter their landing and probing behavior when compared to the control test populations. The reduction in complete blood-feeding was observed at all time periods tested, but was only statistically significant at 3 and 6 h after the preexposure process. Because reduction in blood meal has been associated with increased refeeding, future studies analyzing the effect of this behavior using arbovirus-infected mosquitoes are needed to address the concern of potentially increased vectorial capacity. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. The mode of action of spatial repellents and their impact on vectorial capacity of Anopheles gambiae sensu stricto.

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    Sheila B Ogoma

    Full Text Available Malaria vector control relies on toxicity of insecticides used in long lasting insecticide treated nets and indoor residual spraying. This is despite evidence that sub-lethal insecticides reduce human-vector contact and malaria transmission. The impact of sub-lethal insecticides on host seeking and blood feeding of mosquitoes was measured. Taxis boxes distinguished between repellency and attraction inhibition of mosquitoes by measuring response of mosquitoes towards or away from Transfluthrin coils and humans. Protective effective distance of coils and long-term effects on blood feeding were measured in the semi-field tunnel and in a Peet Grady chamber. Laboratory reared pyrethroid susceptible Anopheles gambiae sensu stricto mosquitoes were used. In the taxis boxes, a higher proportion of mosquitoes (67%-82% were activated and flew towards the human in the presence of Transfluthrin coils. Coils did not hinder attraction of mosquitoes to the human. In the semi-field Tunnel, coils placed 0.3 m from the human reduced feeding by 86% (95% CI [0.66; 0.95] when used as a "bubble" compared to 65% (95% CI [0.51; 0.76] when used as a "point source". Mosquitoes exposed to coils inside a Peet Grady chamber were delayed from feeding normally for 12 hours but there was no effect on free flying and caged mosquitoes exposed in the semi-field tunnel. These findings indicate that airborne pyrethroids minimize human-vector contact through reduced and delayed blood feeding. This information is useful for the development of target product profiles of spatial repellent products that can be used to complement mainstream malaria vector control tools.

  15. Water repellents and water-repellent preservatives for wood

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    R. Sam. Williams; William C. Feist

    1999-01-01

    Water repellents and water-repellent preservatives increase the durability of wood by enabling the wood to repel liquid water. This report focuses on water-repellent finishes for wood exposed outdoors above ground. The report includes a discussion of the effects of outdoor exposure on wood, the characteristics of water repellent and water-repellent preservative...

  16. Gustatory receptor neuron responds to DEET and other insect repellents in the yellow-fever mosquito, Aedes aegypti

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    Sanford, Jillian L.; Shields, Vonnie D. C.; Dickens, Joseph C.

    2013-03-01

    Three gustatory receptor neurons were characterized for contact chemoreceptive sensilla on the labella of female yellow-fever mosquitoes, Aedes aegypti. The neuron with the smallest amplitude spike responded to the feeding deterrent, quinine, as well as N, N-diethyl-3-methylbenzamide and other insect repellents. Two other neurons with differing spikes responded to salt (NaCl) and sucrose. This is the first report of a gustatory receptor neuron specific for insect repellents in mosquitoes and may provide a tool for screening chemicals to discover novel or improved feeding deterrents and repellents for use in the management of arthropod disease vectors.

  17. Irritant and repellent responses of Anopheles harrisoni and Anopheles minimus upon exposure to bifenthrin or deltamethrin using an excito-repellency system and a live host.

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    Kongmee, Monthathip; Boonyuan, Wasana; Achee, Nicole L; Prabaripai, Atchariya; Lerdthusnee, Kriangkrai; Chareonviriyaphap, Theeraphap

    2012-03-01

    Feeding responses of Anopheles harrisoni and An. minimus were evaluated following exposure to 2 pyrethroid insecticides, bifenthrin or deltamethrin, using an excito-repellency test system in the presence and absence of live host cues. The results demonstrated that contact irritancy was the primary action of bifenthrin or deltamethrin in both mosquito species. There was no noncontact repellency effect elicited by either insecticide. Anopheles minimus showed rapid escape response with high mortality rates following direct contact with deltamethrin in the absence of a host and delayed escape responses when a host was present. Similarly, exposure of An. minimus to bifenthrin also elicited a delayed escape response in the presence of a host but with lower mortality rates. In experiments using An. harrisoni, the presence or absence of a host had no significant effect on behavioral responses to either insecticide (P > 0.05). We conclude that deltamethrin elicited stronger irritant chemical effects than bifenthrin but that behavioral responses in vector populations are dampened in the presence of an available host. This information is useful for estimating probability of pathogen transmission when using irritant chemicals in proximity to a blood-meal source.

  18. ORAL INSECT REPELLENTS - INSECT TASTE RECEPTORS AND THEIR ACTION,

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    CULICIDAE, * CHEMORECEPTORS ), INSECT REPELLENTS, ELECTROPHYSIOLOGY, STIMULATION(PHYSIOLOGY), ELECTROLYTES(PHYSIOLOGY), BLOOD, INGESTION(PHYSIOLOGY), REPRODUCTION(PHYSIOLOGY), NUTRITION, ENTOMOLOGY, AEDES, MOUTH

  19. Ethnobotanical study of some of mosquito repellent plants in north-eastern Tanzania

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    Tenu Filemoni

    2008-08-01

    Full Text Available Abstract Background The use of plant repellents against nuisance biting insects is common and its potential for malaria vector control requires evaluation in areas with different level of malaria endemicity. The essential oils of Ocimum suave and Ocimum kilimandscharicum were evaluated against malaria vectors in north-eastern Tanzania. Methodology An ethnobotanical study was conducted at Moshi in Kilimanjaro region north-eastern Tanzania, through interviews, to investigate the range of species of plants used as insect repellents. Also, bioassays were used to evaluate the protective potential of selected plants extracts against mosquitoes. Results The plant species mostly used as repellent at night are: fresh or smoke of the leaves of O. suave and O. kilimandscharicum (Lamiaceae, Azadirachta indica (Meliaceae, Eucalyptus globules (Myrtaceae and Lantana camara (Verbenaceae. The most popular repellents were O. kilimandscharicum (OK and O. suave (OS used by 67% out of 120 households interviewed. Bioassay of essential oils of the two Ocimum plants was compared with citronella and DEET to study the repellence and feeding inhibition of untreated and treated arms of volunteers. Using filter papers impregnated with Ocimum extracts, knockdown effects and mortality was investigated on malaria mosquito Anopheles arabiensis and Anopheles gambiae, including a nuisance mosquito, Culex quinquefasciatus. High biting protection (83% to 91% and feeding inhibition (71.2% to 92.5% was observed against three species of mosquitoes. Likewise the extracts of Ocimum plants induced KD90 of longer time in mosquitoes than citronella, a standard botanical repellent. Mortality induced by standard dosage of 30 mg/m2 on filter papers, scored after 24 hours was 47.3% for OK and 57% for OS, compared with 67.7% for citronella. Conclusion The use of whole plants and their products as insect repellents is common among village communities of north-eastern Tanzania and the results

  20. Potential of Eucalyptus Oil as Repellent against House Rat, Rattus rattus

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    Thind, Ramandeep Kaur; Mahal, Amrit Kaur

    2014-01-01

    Rodent repellents are chemicals which by taste or odour or possibly by both will prevent animal from feeding or gnawing. Such substances may be used in protecting an area from rodent infestation or in protecting packaged food, packing materials, electric cables, and other important vulnerable materials. Mature and healthy house rat, Rattus rattus of both sexes, was exposed to 5, 10, and 20% eucalyptus oil applied as spray in laboratory pens in bichoice tests. Each concentration was applied through three different modes of application, that is, daily, once, and alternatively in a week. Repellent effect of the oil was assessed based on food consumption from treated and untreated sides for four days. In overall, food consumption was significantly (P eucalyptus oil. Present studies reveal the potential of eucalyptus oil in repelling away R. rattus; however, further studies may be conducted to enhance the persistence of repellent effect for longer period of time. PMID:24523633

  1. Toxicity, repellency and flushing out in Triatoma infestans (Hemiptera: Reduviidae exposed to the repellents DEET and IR3535

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    Mercedes M.N. Reynoso

    2017-05-01

    Full Text Available DEET and IR3535 are insect repellents present worldwide in commercial products; their efficacy has been mainly evaluated in mosquitoes. This study compares the toxicological effects and the behavioral responses induced by both repellents on the blood-sucking bug Triatoma infestans Klug (Hemiptera: Reduviidae, one of the main vectors of Chagas disease. When applied topically, the Median Lethal Dose (72 h for DEET was 220.8 µg/insect. Using IR3535, topical application of 500 µg/insect killed no nymphs. The minimum concentration that produced repellency was the same for both compounds: 1,15 µg/cm2. The effect of a mixture DEET:IR3535 1:1 was similar to that of their pure components. Flushing out was assessed in a chamber with a shelter containing groups of ten nymphs. The repellents were aerosolized on the shelter and the number of insects leaving it was recorded for 60 min. During that time, 0.006 g/m3 of the positive control tetramethrin flushed out 76.7% of the nymphs, while 1.76 g/m3 of DEET or IR3535 flushed out 30 and 0%, respectively. The concentrations required for both compounds to produce toxicity or flushing out are too high to have any practical applications. However, they showed a promising repellency. Additional research should be done to evaluate their possible use for personal protection against T. infestans bites.

  2. Repels

    International Nuclear Information System (INIS)

    Maki, M.; Clarke, D.; McKeen, W.

    1991-01-01

    This paper reports on repels (Rapidly Extendible Perimeter Line Sensor) which is a recent development in transportable security technology. Repels utilizes a new coupled wave device technology (CWD) to provide the detection advantages of radio-frequency leaky cable guided radar for portable sensors. These advantages include an invisible, terrain-following detection zone, and an optimal detection characteristic for human-size targets. Repels adds the dimension of portability and set-up of an adjustable zone up to 100 m by a single person, typically within 20 minutes. Internal replaceable D-cell flashlight batteries provide power for weeks of operation. First introduced as a prototype for test and evaluation in 1988, Repels was launched as a Senstar NDI product in 1990. This paper outlines the technical principles of the Repels sensor, recent improvements from the original prototype results of early field test experience on production models, and applications. Recent advances driven by initial field tests include, for example, the use of inductively-coupled transmitter and receiver couplers, so that no radio frequency field connections are required, and simple conductors can be employed. Test and application experience in several countries has expanded from parked aircraft perimeters, military encampments, forward area surveillance, and waterside security, to dignitary protection and failed sensor stand-in. Such sensors may be used to protect facilities dealing with nuclear materials

  3. orco mutant mosquitoes lose strong preference for humans and are not repelled by volatile DEET.

    Science.gov (United States)

    DeGennaro, Matthew; McBride, Carolyn S; Seeholzer, Laura; Nakagawa, Takao; Dennis, Emily J; Goldman, Chloe; Jasinskiene, Nijole; James, Anthony A; Vosshall, Leslie B

    2013-06-27

    Female mosquitoes of some species are generalists and will blood-feed on a variety of vertebrate hosts, whereas others display marked host preference. Anopheles gambiae and Aedes aegypti have evolved a strong preference for humans, making them dangerously efficient vectors of malaria and Dengue haemorrhagic fever. Specific host odours probably drive this strong preference because other attractive cues, including body heat and exhaled carbon dioxide (CO2), are common to all warm-blooded hosts. Insects sense odours via several chemosensory receptor families, including the odorant receptors (ORs), membrane proteins that form heteromeric odour-gated ion channels comprising a variable ligand-selective subunit and an obligate co-receptor called Orco (ref. 6). Here we use zinc-finger nucleases to generate targeted mutations in the orco gene of A. aegypti to examine the contribution of Orco and the odorant receptor pathway to mosquito host selection and sensitivity to the insect repellent DEET (N,N-diethyl-meta-toluamide). orco mutant olfactory sensory neurons have greatly reduced spontaneous activity and lack odour-evoked responses. Behaviourally, orco mutant mosquitoes have severely reduced attraction to honey, an odour cue related to floral nectar, and do not respond to human scent in the absence of CO2. However, in the presence of CO2, female orco mutant mosquitoes retain strong attraction to both human and animal hosts, but no longer strongly prefer humans. orco mutant females are attracted to human hosts even in the presence of DEET, but are repelled upon contact, indicating that olfactory- and contact-mediated effects of DEET are mechanistically distinct. We conclude that the odorant receptor pathway is crucial for an anthropophilic vector mosquito to discriminate human from non-human hosts and to be effectively repelled by volatile DEET.

  4. Use of gamma-irradiated blood for feeding tsetse flies

    International Nuclear Information System (INIS)

    Bauer, B.; Iwannek, K.H.; Hamann, H.J.; Adamsky, G.

    1980-01-01

    Freshly collected pig blood was sterilized by 60 Co gamma irradiation. A dose of 100 krad proved to be effective against Pseudomonas aeruginosa at concentrations of at least 4.7x10 5 /ml. Glossina morsitans morsitans (Westw.) were maintained on this blood by feeding them five days per week on silicone membrane for nine months. Their performance was compared with a control fed untreated blood. In spite of the slightly faster haemolysis of the irradiated blood, the results from the experimental group compared favourably with the control. This was especially true for the percentage of daily mortality. The irradiation seems to offer a promising approach for the establishment of mass rearing plants in Africa based on in vitro feeding provided the blood from donor animals is suitable for tsetse flies. (author)

  5. Optimization of sugar and blood feeding regimen in Anopheles gambiae mass production system

    International Nuclear Information System (INIS)

    Sedofia, B. K

    2013-07-01

    The sterile insect technique (SIT) is being developed for the control of malaria transmitting mosquitoes. Critical to the success of applying the SIT is the establishment of standardized mass production systems for the target species. As part of efforts to develop standardised mass production systems for malaria vectors, this project sought to optimize adult blood and sugar feeding in a mass production system. Different sugar types (glucose, sucrose and honey) were evaluated at 6% and 10% concentrations in water to determine the best sugar diet and concentration for feeding adult An. gambiae. Different blood feeding methods, restrained Guinea pig, anaesthetised Guinea pig and human arm feeding were evaluated. Adult survival, female insemination and egg production were used as criteria to determine optimum sugar and blood feeding. The effect of anaesthetics on blood feeding response and egg production of female An. gambiae was determined by comparing feeding response and egg production of females fed with anaesthetised Guinea pigs as against physically restrained Guinea pigs (Control). The specific effect of different anaesthetic agents on blood feeding response and egg production of female mosquitoes were was also determined by comparing the feeding response and egg production of females fed with either Ketamine/Xylazine anaesthetised Guinea pigs or Ketamine/Diazepam anaesthetised Guinea pigs. Effects due to sugar types and concentrations on percentage survival of male and female mosquitoes were observed to be significant at (p 0.05). However, human ann feeding (HAP) method and Ketamine/Xylazine (KX) anaesthetics fed for 25 minutes recorded higher percentage feeding (76.0% and 68.0% respectively) and egg production of 19.0% and 20.8% respectively. Anaesthetised Guinea pig feeding (AGF) of adults for 15 minutes followed closely with 60.0% and 15.1% blood feeding and egg production respectively whilst restrained Guinea pig feeding (RGF) method and Ketamine

  6. Laboratory rearing of Cimex hemipterus F. (Hemiptera: Cimicidae feeding on different types of human blood compositions by using modifid artifiial feeding system

    Directory of Open Access Journals (Sweden)

    Abd Hafis Abd Rahim

    2015-12-01

    Full Text Available Objective: To investigate the effects of three types of human blood compositions: whole blood, red blood cells and red blood cells mixed with plasma, and determine the suitable blood source that can be used to feed the bed bugs [Cimex hemipterus (C. hemipterus], in comparison to the direct feeding method. Methods: C. hemipterus were fed with the three types of blood compositions by using an artificial feeding system. Then the number of live and dead individuals as well as the number of adults produced was counted. Results: Red blood cells caused 72.7% death of C. hemipterus, followed by red blood cells mixed with plasma (52.0% and whole blood (48.7%. There were significant differences in the number of live individuals after seven weeks of feeding. However, there were no significant differences between the number of live individuals fed on whole blood, red blood cells and red blood cells mixed with plasma after seven weeks. Conclusions: The components in the blood sources may be the key to their different effects on the growth dynamics of C. hemipterus.

  7. Feeding response of Aedes aegypti and Anopheles dirus (Diptera: Culicidae) using out-of-date human blood in a membrane feeding apparatus.

    Science.gov (United States)

    Pothikasikorn, Jinrapa; Boonplueang, Rapee; Suebsaeng, Chalermchai; Khaengraeng, Rungpetch; Chareonviriyaphap, Theeraphap

    2010-06-01

    The colonization of Aedes aegypti and Anopheles dirus was performed using out-of-date human blood from a blood bank as a nutritional supply dispensed from a common artificial feeder. Preserved human blood was collected and used for feeding on days 5, 15, and 25 after date of expiration and dispensed from a common artificial feeder to rear the mosquitoes. Ae. aegypti had a feeding rate of 78.7, 62, and 18% at the respective intervals while An. dirus had a rate of 80, 56.8, and 7.3% on the same respective days. Direct feeding on live hamsters resulted in a rate of 96 and 90% for Ae. aegypti and An. dirus, respectively. Although egg production rates decreased from the day 5 feeding to the day 25 feeding, all of the developmental stages resulting from An. dirus fed at day 5 and 15 showed insignificant differences when compared with direct feeding on the blood of a hamster.

  8. Different blood and sugar feeding regimes affect the productivity of Anopheles arabiensis colonies (Diptera: Culicidae).

    Science.gov (United States)

    Damiens, D; Soliban, S M; Balestrino, F; Alsir, R; Vreysen, M J B; Gilles, J R L

    2013-03-01

    The success of the sterile insect technique for the management of mosquito populations depends on the release of large numbers of competitive sterile male insects. Sustainable mosquito production can only be obtained when proper mass-rearing equipment and adequate methods are available, including those to feed blood to the female mosquitoes. The blood feeding apparatus Hemotek consists of a small aluminum plate to which a collagen membrane is fixed and filled with blood kept warm by an electric heating element. A larger aluminum plate was developed to feed a larger number of female mosquitoes with blood that is kept at a constant temperature. The effect of different blood feeding regimes (feeding frequency and time the blood is kept in the Hemotek) and sugar deprivation before blood feeding on egg production of female Anopheles arabiensis Patton was tested. Egg production was higher when blood was offered to the mosquitoes every day as compared with every 2 or 4 d. Sugar deprivation for 7 h before blood feeding enhanced egg production by 50% compared with female mosquitoes that had continuous access to sugar. Neither male nor female survival was impaired. Finally, we showed that the same blood could be kept warm and used over several hours to feed mosquitoes in multiple cages without any impact on egg production or hatch rate. Being able to use the same blood over extended periods would save considerable time, handling, and funds.

  9. Nectar Theft and Floral Ant-Repellence: A Link between Nectar Volume and Ant-Repellent Traits?

    Science.gov (United States)

    Ballantyne, Gavin; Willmer, Pat

    2012-01-01

    As flower visitors, ants rarely benefit a plant. They are poor pollinators, and can also disrupt pollination by deterring other flower visitors, or by stealing nectar. Some plant species therefore possess floral ant-repelling traits. But why do particular species have such traits when others do not? In a dry forest in Costa Rica, of 49 plant species around a third were ant-repellent at very close proximity to a common generalist ant species, usually via repellent pollen. Repellence was positively correlated with the presence of large nectar volumes. Repellent traits affected ant species differently, some influencing the behaviour of just a few species and others producing more generalised ant-repellence. Our results suggest that ant-repellent floral traits may often not be pleiotropic, but instead could have been selected for as a defence against ant thieves in plant species that invest in large volumes of nectar. This conclusion highlights to the importance of research into the cost of nectar production in future studies into ant-flower interactions. PMID:22952793

  10. Repellent Action Of Neem (Azadiracta India Seed Oil Against Aedes Aegypti Mosquitoes

    Directory of Open Access Journals (Sweden)

    Hati A K

    1995-01-01

    Full Text Available Neem (Azadiracta India seed oil in appropriate amount when smeared on the surface of the hand showed excellent repellent action against Aedes aegypti mosquitoes. When 1 ml of oil was spread on the hand, with an approximate area of 160 sq cm the percentage of alighting and blood fed mosquitoes in the experimental cages varied from 14 to 78 and 4 to 46 respectively. This percentage decreased to 6 to 18 and 0 to 16 respectively when the amount of oil applied was 1.5 ml. Only 0-4% of the mosquitoes alighted on the skin of which 2% only took the blood meal when 2 ml of the oil was used to cover the hand. In the control cages cent percent of the mosquitoes alighted and sucked blood. The repellent action was directly proportional to the hour of exposure to the oil. It was also observed that even after alighting on a oil- smeared skin a sizeable proportion of mosquitoes were not able to imbibe blood meal. Neem seed oil was non-toxic, non- irritating to skin.

  11. Sharks senses and shark repellents.

    Science.gov (United States)

    Hart, Nathan S; Collin, Shaun P

    2015-01-01

    Despite over 70 years of research on shark repellents, few practical and reliable solutions to prevent shark attacks on humans or reduce shark bycatch and depredation in commercial fisheries have been developed. In large part, this deficiency stems from a lack of fundamental knowledge of the sensory cues that drive predatory behavior in sharks. However, the widespread use of shark repellents is also hampered by the physical constraints and technical or logistical difficulties of deploying substances or devices in an open-water marine environment to prevent an unpredictable interaction with a complex animal. Here, we summarize the key attributes of the various sensory systems of sharks and highlight residual knowledge gaps that are relevant to the development of effective shark repellents. We also review the most recent advances in shark repellent technology within the broader historical context of research on shark repellents and shark sensory systems. We conclude with suggestions for future research that may enhance the efficacy of shark repellent devices, in particular, the continued need for basic research on shark sensory biology and the use of a multi-sensory approach when developing or deploying shark repellent technology. © 2014 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

  12. Feed efficiency, blood parameters, and ingestive behavior of young Nellore males and females.

    Science.gov (United States)

    Bonilha, Sarah Figueiredo Martins; Cyrillo, Joslaine Noely dos Santos Gonçalves; dos Santos, Guilherme Pinheiro; Branco, Renata Helena; Ribeiro, Enilson Geraldo; Mercadante, Maria Eugênia Zerlotti

    2015-10-01

    This study aimed to evaluate differences in efficiency of feed utilization between young Nellore males and females by comparing growth traits, feed intake, blood parameters, and ingestive behavior of the animals. Data from 768 Nellore males and females that participated in eight performance tests for individual feed intake evaluation were used. Performance and feed efficiency measures, efficiency-related hematological, metabolic and hormonal variables, and data regarding ingestive behavior were collected. Feed efficiency measures were defined by the relationship between performance and feed intake. Data were analyzed using mixed models that included the fixed effects of sex, herd, and the covariate age within sex and the random effects of facility within year, year, and residual. Significant differences between males and females were observed for traits related to weight gain and feed intake. Although individual dynamics of feed efficiency measures differed between males and females, no significant differences in residual feed intake, feed efficiency, or relative growth rate were observed between sexes. Significant differences between sexes were found for platelets, red blood cells, hemoglobin, creatinine, glucose, urea, triglycerides, insulin, cortisol, and IGF-I. Females spent more time feeding and less time ruminating when compared to males. However, males exhibited higher feeding efficiency and lower rumination efficiency than females. Growing Nellore males and females are efficient in feed utilization, and the differences in blood variables observed are probably due to differences in body size and feed intake. Males spend less time eating, consume more food, and spend more time ruminating than females.

  13. Colonization of Lutzomyia shannoni (Diptera: Psychodidae) utilizing an artificial blood feeding technique.

    Science.gov (United States)

    Mann, Rajinder S; Kaufman, Phillip E

    2010-12-01

    Laboratory colonization of hematophagous insects must include an efficient method of blood feeding, preferably by artificial means. Strict rules for obtaining animal use permits, extensive animal maintenance costs, and indirect anesthesia effects on animal health warrant the development of an artificial membrane feeding technique for sand fly colonization in laboratories. An attempt was made to colonize Lutzomyia shannoni using an artificial blood feeding membrane to replace the use of live animals commonly used for sand fly blood-feeding purposes. Lutzomyia shannoni readily fed through a pig intestine membrane exposed at an angle of 45°. However, it did not feed through a chicken skin membrane. Olfactory attractants were unable to improve blood-feeding efficiency. Plaster of Paris was the most suitable oviposition substrate. Female L. shannoni adults laid no eggs on moist sand substrate. Sand fly adults held in groups of ten or more laid higher numbers of eggs than did individually maintained sand flies. Inclusion of the L. longipalpis oviposition hormone dodecanoic acid or the presence of previously laid eggs did not stimulate L. shannoni oviposition. The average L. shannoni egg, larval, and pupal duration were 9.3, 36.7, and 17.8 days, respectively. The addition of a 20% sugar solution improved adult female longevity. Females survived longer (14.8 days) than males (11.9 days). Lutzomyia shannoni was successfully colonized in the laboratory for up to four generations using this artificial membrane technique. © 2010 The Society for Vector Ecology.

  14. Health, body condition and blood metabolites in reindeer after submaintenance feed intake and subsequent feeding

    Directory of Open Access Journals (Sweden)

    A. Nilsson

    2000-03-01

    Full Text Available The transition from experimentally induced poor nutritional conditions to feeding was studied with 69 eight-month-old female reindeer (Rangifer tarandus tarandus. During a pre-experimental period, all reindeer were fed a simulated winter diet with 80% lichens Cladina spp. and 20% Vaccinum myrtillus shrubs and Salix spp. leaves (lichen diet ad lib. The reindeer were divided into five groups. A control group (group C was fed the lichen diet ad lib. throughout the experiment. Four groups were fed half of that ration for eight days and were then totally deprived of feed for one day (restriction period. During the following 34 days (feeding period the groups were re-fed the lichen diet (group L, fed pelleted reindeer feed combined with either lichen (group PL or grass silage (group PS, or fed silage with a gradually increasing addition of pellets (group SP. Weekly measurements of blood samples and body weighr showed that the control group remained clinically healthy and had stable blood plasma concentrations of protein, urea, glucose and insulin throughout the experiment, but they lost weight. At slaughter, before and after the restriction period, all animals had lost rumen-free body weight, but the reindeer fed a restricted amount of feed lost more than the control group. Also the plasma metabolites were affected by the restricted feeding, with increased concentrations of urea and decreased concentrations of glucose. Group L responded immediately to the ad lib. feeding with blood metabolite levels rapidly approaching those of group C. The body weight developments were similar in groups L and C. Although the feed rations were increased gradually, diarrhoea occurred in some animals belonging to groups PL and PS within the first week of the feeding period. All reindeer recovered, after antibiotic treatment of the worst affected animals. The PL and PS groups, which had high contents of metabolisable energy and crude protein in their diets, showed

  15. Repellency of 29 Synthetic and Natural Commercial Topical Insect Repellents Against Aedes aegypti (Diptera: Culicidae) in Central Mexico.

    Science.gov (United States)

    Kuri-Morales, Pablo A; Correa-Morales, Fabián; González-Acosta, Cassandra; Sánchez-Tejeda, Gustavo; Moreno-Garcia, Miguel; Dávalos-Becerril, Eduardo; Juárez-Franco, Marissa F; Benitez-Alva, José Ismael; González-Roldán, Jesús F

    2017-09-01

    In Mexico, the use of repellents to prevent insects from landing and biting is a common practice. However, variation in the efficiency of natural and synthetic repellents has been observed. In this study, we evaluated the repellency and protection time of 16 synthetic and 13 natural-based commercial products against Aedes aegypti (L.) from an endemic dengue area (Jojutla, Morelos) in Central Mexico. The "arm exposure" cage test was used to assess the efficacy of the repellents. Tests were conducted by three adult volunteers. Results showed that DEET (N, N-Diethyl-3-methylbenzamide) repellents provided the highest protection and duration times against Ae. aegypti. However, low repellency and short-time protection was observed (when compared with the manufacturers' protection times). Natural-based products did not repel (either landing or biting) mosquitoes for >30 min. These results show that most of the repellent products did not provide satisfactory levels of personal protection against mosquito bites. Frequent reapplication of repellents (synthetic and natural-based) may compensate for their short duration of action. Repellent efficacy data must be integrated into the decision-making process for an optimal response to the local (or specific region) situation. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Efficacy of Blood Sources and Artificial Blood Feeding Methods in Rearing of Aedes aegypti (Diptera: Culicidae) for Sterile Insect Technique and Incompatible Insect Technique Approaches in Sri Lanka.

    Science.gov (United States)

    Gunathilaka, Nayana; Ranathunge, Tharaka; Udayanga, Lahiru; Abeyewickreme, Wimaladharma

    2017-01-01

    Selection of the artificial membrane feeding technique and blood meal source has been recognized as key considerations in mass rearing of vectors. Artificial membrane feeding techniques, namely, glass plate, metal plate, and Hemotek membrane feeding method, and three blood sources (human, cattle, and chicken) were evaluated based on feeding rates, fecundity, and hatching rates of Aedes aegypti . Significance in the variations among blood feeding was investigated by one-way ANOVA, cluster analysis of variance (ANOSIM), and principal coordinates (PCO) analysis. Feeding rates of Ae. aegypti significantly differed among the membrane feeding techniques as suggested by one-way ANOVA ( p feeding technique. Blood feeding rate of Ae. aegypti was higher with human blood followed by cattle and chicken blood, respectively. However, no significant difference was observed from the mosquitoes fed with cattle and human blood, in terms of fecundity, oviposition rate, and fertility as suggested by one-way ANOVA ( p > 0.05). Metal plate method could be recommended as the most effective membrane feeding technique for mass rearing of Ae. aegypti , due to its high feeding rate and cost effectiveness. Cattle blood could be recommended for mass rearing Ae. aegypti .

  17. Can topical insect repellents reduce malaria? A cluster-randomised controlled trial of the insect repellent N,N-diethyl-m-toluamide (DEET in Lao PDR.

    Directory of Open Access Journals (Sweden)

    Vanessa Chen-Hussey

    Full Text Available BACKGROUND: Mosquito vectors of malaria in Southeast Asia readily feed outdoors making malaria control through indoor insecticides such as long-lasting insecticidal nets (LLINs and indoor residual spraying more difficult. Topical insect repellents may be able to protect users from outdoor biting, thereby providing additional protection above the current best practice of LLINs. METHODS AND FINDINGS: A double blind, household randomised, placebo-controlled trial of insect repellent to reduce malaria was carried out in southern Lao PDR to determine whether the use of repellent and long-lasting insecticidal nets (LLINs could reduce malaria more than LLINs alone. A total of 1,597 households, including 7,979 participants, were recruited in June 2009 and April 2010. Equal group allocation, stratified by village, was used to randomise 795 households to a 15% DEET lotion and the remainder were given a placebo lotion. Participants, field staff and data analysts were blinded to the group assignment until data analysis had been completed. All households received new LLINs. Participants were asked to apply their lotion to exposed skin every evening and sleep under the LLINs each night. Plasmodium falciparum and P. vivax cases were actively identified by monthly rapid diagnostic tests. Intention to treat analysis found no effect from the use of repellent on malaria incidence (hazard ratio: 1.00, 95% CI: 0.99-1.01, p = 0.868. A higher socio-economic score was found to significantly decrease malaria risk (hazard ratio: 0.72, 95% CI: 0.58-0.90, p = 0.004. Women were also found to have a reduced risk of infection (hazard ratio: 0.59, 95% CI: 0.37-0.92, p = 0.020. According to protocol analysis which excluded participants using the lotions less than 90% of the time found similar results with no effect from the use of repellent. CONCLUSIONS: This randomised controlled trial suggests that topical repellents are not a suitable intervention in addition to

  18. Countercurrent heat exchange and thermoregulation during blood-feeding in kissing bugs.

    Science.gov (United States)

    Lahondère, Chloé; Insausti, Teresita C; Paim, Rafaela Mm; Luan, Xiaojie; Belev, George; Pereira, Marcos H; Ianowski, Juan P; Lazzari, Claudio R

    2017-11-21

    Blood-sucking insects experience thermal stress at each feeding event on endothermic vertebrates. We used thermography to examine how kissing-bugs Rhodnius prolixus actively protect themselves from overheating. During feeding, these bugs sequester and dissipate the excess heat in their heads while maintaining an abdominal temperature close to ambient. We employed a functional-morphological approach, combining histology, µCT and X-ray-synchrotron imaging to shed light on the way these insects manage the flow of heat across their bodies. The close alignment of the circulatory and ingestion systems, as well as other morphological characteristics, support the existence of a countercurrent heat exchanger in the head of R. prolixus , which decreases the temperature of the ingested blood before it reaches the abdomen. This kind of system has never been described before in the head of an insect. For the first time, we show that countercurrent heat exchange is associated to thermoregulation during blood-feeding.

  19. Gustatory receptor neuron responds to DEET and other insect repellents in the yellow fever mosquito, aedes aegypti

    Science.gov (United States)

    Three gustatory receptor neurons were characterized for contact chemoreceptive sensilla on the labella of female yellow fever mosquitoes, Aedes aegypti. The neuron with the smallest amplitude spike responded to the feeding deterrent, quinine, as well as DEET and other insect repellents. Two other ...

  20. Field evaluation of picaridin repellents reveals differences in repellent sensitivity between Southeast Asian vectors of malaria and arboviruses.

    Directory of Open Access Journals (Sweden)

    Karel Van Roey

    2014-12-01

    Full Text Available Scaling up of insecticide treated nets has contributed to a substantial malaria decline. However, some malaria vectors, and most arbovirus vectors, bite outdoors and in the early evening. Therefore, topically applied insect repellents may provide crucial additional protection against mosquito-borne pathogens. Among topical repellents, DEET is the most commonly used, followed by others such as picaridin. The protective efficacy of two formulated picaridin repellents against mosquito bites, including arbovirus and malaria vectors, was evaluated in a field study in Cambodia. Over a period of two years, human landing collections were performed on repellent treated persons, with rotation to account for the effect of collection place, time and individual collector. Based on a total of 4996 mosquitoes collected on negative control persons, the overall five hour protection rate was 97.4% [95%CI: 97.1-97.8%], not decreasing over time. Picaridin 20% performed equally well as DEET 20% and better than picaridin 10%. Repellents performed better against Mansonia and Culex spp. as compared to aedines and anophelines. A lower performance was observed against Aedes albopictus as compared to Aedes aegypti, and against Anopheles barbirostris as compared to several vector species. Parity rates were higher in vectors collected on repellent treated person as compared to control persons. As such, field evaluation shows that repellents can provide additional personal protection against early and outdoor biting malaria and arbovirus vectors, with excellent protection up to five hours after application. The heterogeneity in repellent sensitivity between mosquito genera and vector species could however impact the efficacy of repellents in public health programs. Considering its excellent performance and potential to protect against early and outdoor biting vectors, as well as its higher acceptability as compared to DEET, picaridin is an appropriate product to evaluate the

  1. Field evaluation of picaridin repellents reveals differences in repellent sensitivity between Southeast Asian vectors of malaria and arboviruses.

    Science.gov (United States)

    Van Roey, Karel; Sokny, Mao; Denis, Leen; Van den Broeck, Nick; Heng, Somony; Siv, Sovannaroth; Sluydts, Vincent; Sochantha, Tho; Coosemans, Marc; Durnez, Lies

    2014-12-01

    Scaling up of insecticide treated nets has contributed to a substantial malaria decline. However, some malaria vectors, and most arbovirus vectors, bite outdoors and in the early evening. Therefore, topically applied insect repellents may provide crucial additional protection against mosquito-borne pathogens. Among topical repellents, DEET is the most commonly used, followed by others such as picaridin. The protective efficacy of two formulated picaridin repellents against mosquito bites, including arbovirus and malaria vectors, was evaluated in a field study in Cambodia. Over a period of two years, human landing collections were performed on repellent treated persons, with rotation to account for the effect of collection place, time and individual collector. Based on a total of 4996 mosquitoes collected on negative control persons, the overall five hour protection rate was 97.4% [95%CI: 97.1-97.8%], not decreasing over time. Picaridin 20% performed equally well as DEET 20% and better than picaridin 10%. Repellents performed better against Mansonia and Culex spp. as compared to aedines and anophelines. A lower performance was observed against Aedes albopictus as compared to Aedes aegypti, and against Anopheles barbirostris as compared to several vector species. Parity rates were higher in vectors collected on repellent treated person as compared to control persons. As such, field evaluation shows that repellents can provide additional personal protection against early and outdoor biting malaria and arbovirus vectors, with excellent protection up to five hours after application. The heterogeneity in repellent sensitivity between mosquito genera and vector species could however impact the efficacy of repellents in public health programs. Considering its excellent performance and potential to protect against early and outdoor biting vectors, as well as its higher acceptability as compared to DEET, picaridin is an appropriate product to evaluate the epidemiological

  2. Efficacy of Blood Sources and Artificial Blood Feeding Methods in Rearing of Aedes aegypti (Diptera: Culicidae) for Sterile Insect Technique and Incompatible Insect Technique Approaches in Sri Lanka

    OpenAIRE

    Nayana Gunathilaka; Tharaka Ranathunge; Lahiru Udayanga; Wimaladharma Abeyewickreme

    2017-01-01

    Introduction Selection of the artificial membrane feeding technique and blood meal source has been recognized as key considerations in mass rearing of vectors. Methodology Artificial membrane feeding techniques, namely, glass plate, metal plate, and Hemotek membrane feeding method, and three blood sources (human, cattle, and chicken) were evaluated based on feeding rates, fecundity, and hatching rates of Aedes aegypti. Significance in the variations among blood feeding was investigated by one...

  3. Is the expression of autogeny by Culex molestus Forskal (Diptera: Culicidae) influenced by larval nutrition or by adult mating, sugar feeding, or blood feeding?

    Science.gov (United States)

    Kassim, Nur Faeza A; Webb, Cameron E; Russell, Richard C

    2012-06-01

    Culex molestus Forskal is suspected to have been introduced into southern Australia during the 1940s. Investigations to determine factors influencing the expression of autogeny, the response of this mosquito to potential blood meals, and the subsequent influence on oviposition were undertaken. Immature mosquitoes raised at five feeding regimes had mortality rates, development rates, wing length, and autogenous egg raft size measured. All surviving female mosquitoes laid autogenous eggs but there was a significant difference between the mean number of eggs per raft. For mosquitoes raised at each of the feeding regimes, there was a significant linear relationship between the number of eggs per autogenous egg raft and wing length. Newly emerged mosquitoes were offered a blood meal (i.e., rodent) daily but no blood feeding occurred until the autogenous egg raft was laid. There was no statistical difference in the rate of autogenous oviposition or post-oviposition blood feeding between control or treatment groups. The results of this study indicate that Cx. molestus is perfectly adapted to subterranean habitats in close association with human habitation, but their preference to delay blood feeding until up to day 8 following emergence may reduce their relative importance as a vector of arboviruses. © 2012 The Society for Vector Ecology.

  4. Meeting the challenges of on-host and off-host water balance in blood-feeding arthropods.

    Science.gov (United States)

    Benoit, Joshua B; Denlinger, David L

    2010-10-01

    In this review, we describe water balance requirements of blood-feeding arthropods, particularly contrasting dehydration tolerance during the unfed, off-host state and the challenges of excess water that accompany receipt of the bloodmeal. Most basic water balance characteristics during the off-host stage are applicable to other terrestrial arthropods, as well. A well-coordinated suite of responses enable arthropods to conserve water resources, enhance their desiccation tolerance, and increase their water supplies by employing a diverse array of molecular, structural and behavioral responses. Water loss rates during the off-host phase are particularly useful for generating a scheme to classify vectors according to their habitat requirements for water, thus providing a convenient tool with potential predictive power for defining suitable current and future vector habitats. Blood-feeding elicits an entirely different set of challenges as the vector responds to overhydration by quickly increasing its rate of cuticular water loss and elevating the rate of diuresis to void excess water and condense the bloodmeal. Immature stages that feed on blood normally have a net increase in water content at the end of a blood-feeding cycle, but in adults the water content reverts to the pre-feeding level when the cycle is completed. Common themes are evident in diverse arthropods that feed on blood, particularly the physiological mechanisms used to respond to the sudden influx of water as well as the mechanisms used to counter water shortfalls that are encountered during the non-feeding, off-host state. Copyright 2010 Elsevier Ltd. All rights reserved.

  5. Efficacy of Blood Sources and Artificial Blood Feeding Methods in Rearing of Aedes aegypti (Diptera: Culicidae for Sterile Insect Technique and Incompatible Insect Technique Approaches in Sri Lanka

    Directory of Open Access Journals (Sweden)

    Nayana Gunathilaka

    2017-01-01

    Full Text Available Introduction. Selection of the artificial membrane feeding technique and blood meal source has been recognized as key considerations in mass rearing of vectors. Methodology. Artificial membrane feeding techniques, namely, glass plate, metal plate, and Hemotek membrane feeding method, and three blood sources (human, cattle, and chicken were evaluated based on feeding rates, fecundity, and hatching rates of Aedes aegypti. Significance in the variations among blood feeding was investigated by one-way ANOVA, cluster analysis of variance (ANOSIM, and principal coordinates (PCO analysis. Results. Feeding rates of Ae. aegypti significantly differed among the membrane feeding techniques as suggested by one-way ANOVA (p0.05. Conclusions. Metal plate method could be recommended as the most effective membrane feeding technique for mass rearing of Ae. aegypti, due to its high feeding rate and cost effectiveness. Cattle blood could be recommended for mass rearing Ae. aegypti.

  6. Dynamics of digestive proteolytic system during blood feeding of the hard tick Ixodes ricinus

    Directory of Open Access Journals (Sweden)

    Sojka Daniel

    2010-12-01

    Full Text Available Abstract Background Ticks are vectors of a wide variety of pathogens causing severe diseases in humans and domestic animals. Intestinal digestion of the host blood is an essential process of tick physiology and also a limiting factor for pathogen transmission since the tick gut represents the primary site for pathogen infection and proliferation. Using the model tick Ixodes ricinus, the European Lyme disease vector, we have previously demonstrated by genetic and biochemical analyses that host blood is degraded in the tick gut by a network of acidic peptidases of the aspartic and cysteine classes. Results This study reveals the digestive machinery of the I. ricinus during the course of blood-feeding on the host. The dynamic profiling of concentrations, activities and mRNA expressions of the major digestive enzymes demonstrates that the de novo synthesis of peptidases triggers the dramatic increase of the hemoglobinolytic activity along the feeding period. Overall hemoglobinolysis, as well as the activity of digestive peptidases are negligible at the early stage of feeding, but increase dramatically towards the end of the slow feeding period, reaching maxima in fully fed ticks. This finding contradicts the established opinion that blood digestion is reduced at the end of engorgement. Furthermore, we show that the digestive proteolysis is localized intracellularly throughout the whole duration of feeding. Conclusions Results suggest that the egressing proteolytic system in the early stage of feeding and digestion is a potential target for efficient impairment, most likely by blocking its components via antibodies present in the host blood. Therefore, digestive enzymes are promising candidates for development of novel 'anti-tick' vaccines capable of tick control and even transmission of tick-borne pathogens.

  7. Blood-feeding ecology of mosquitoes in zoos.

    Science.gov (United States)

    Tuten, H C; Bridges, W C; Paul, K S; Adler, P H

    2012-12-01

    To determine if the unique host assemblages in zoos influence blood-feeding by mosquitoes (Diptera: Culicidae), a sampling programme was conducted in Greenville and Riverbanks Zoos, South Carolina, U.S.A., from April 2009 to October 2010. A total of 4355 female mosquitoes of 14 species were collected, of which 106 individuals of nine species were blood-fed. The most common taxa were Aedes albopictus (Skuse), Aedes triseriatus (Say), Anopheles punctipennis (Say), Culex erraticus (Dyar & Knab), Culex pipiens complex (L.) and Culex restuans (Theobald). Molecular analyses (cytochrome b) of bloodmeals revealed that mosquitoes fed on captive animals, humans and wildlife, and took mixed bloodmeals. Host species included one amphibian, 16 birds, 10 mammals (including humans) and two reptiles. Minimum dispersal distances after feeding on captive hosts ranged from 15.5 m to 327.0 m. Mosquito-host associations generally conformed to previous accounts, indicating that mosquito behaviour inside zoos reflects that outside zoos. However, novel variation in host use, including new, exotic host records, warrants further investigation. Zoos, thus, can be used as experiment environments in which to study mosquito behaviour, and the findings extrapolated to non-zoo areas, while providing medical and veterinary benefits to zoo animals, employees and patrons. © 2012 The Authors. Medical and Veterinary Entomology © 2012 The Royal Entomological Society.

  8. [Evaluation of effectiveness of several repellents against mosquito bites available at the Polish market].

    Science.gov (United States)

    Mikulak, Ewa; Gliniewicz, Aleksandra; Królasik, Agnieszka; Sawicka, Bozena; Rabczenko, Daniel

    2012-01-01

    BACKGROUND. Mosquitoes are blood-sucking insects, nuisance to humans and animals. Their bites cause itching and allergic reactions. These insects are also vectors of several viruses, bacteria and parasites. Protection against mosquitoes is therefore justified and desirable. This can give repellents and products for protection small outdoor areas such as terraces, home gardens. OBJECTIVE. The aim of this study was to evaluate the effectiveness of eight selected products with different formulations used against mosquitoes including: 5 preparations for use on the body or clothing (repellents A, B, C, D, E and 3 products for use in small outdoor spaces (I, J, K). [corrected] Repellents were tested in laboratory trials, when volunteers were exposed to Aedes aegypti females breeding in the laboratory. Products I, J, K were tested in field trials; volunteers were exposed to female mosquitoes at various ages from the environment (Aedes sp, Culex sp). The results showed that all tested repellents were efficient during 4 hrs. After this time their effectiveness decreased--fast in the case of repellent B (10% DEET), not very fast, but significant--in the case of repellent C (15% DEET). Three products for small area protection gave (each of them) 3-hour protection against mosquito bites. Product K (21,97% allethrin) was 100% effective (no bites at all). Both kinds of product can give effective protection against mosquito bites. Their use is most effective, cheaper and more safe for the environment method of protection against mosquitoes than chemical spraying of large areas.

  9. Studies on the post-oviposition blood-feeding behaviour of Aedes aegypti (L.) (Diptera: Culicidae) in the laboratory.

    Science.gov (United States)

    Chadee, D D

    2012-11-01

    The blood-feeding behaviour of the Trinidad strain of Aedes aegypti was studied, under laboratory conditions, using one female per cage and monitoring blood feeding immediately, 12, and 24 hours after oviposition. To get large numbers of females that had newly completed their first gonotrophic cycle, the diel oviposition periodicity was conducted using single females per cage and monitoring at 2-hour intervals. The diel oviposition periodicity showed a small morning peak (8%) during the first 2 hours of the photophase after which oviposition declined: during the second half of the photophase, oviposition increased reaching a peak comprising 56% of eggs (G = 59·9, P>0·01) between 16:00 and 18:00 hours. At post-oviposition hour 0, only five (10%) of the females accepted a blood meal but at post-oviposition hour 12, significantly more (G = 46·98, P>0·02) females, 35 (70%) accepted a blood meal. This pattern was consistently observed when females were offered blood meals at 12 and 24 hours after completing their first gonotrophic cycle. Multiple feeding was observed among the blood-feeding females and the results of this study are discussed in the context of disease transmission patterns and physiological mechanisms which control their blood-feeding behaviours.

  10. Wolbachia infection reduces blood-feeding success in the dengue fever mosquito, Aedes aegypti.

    Science.gov (United States)

    Turley, Andrew P; Moreira, Luciano A; O'Neill, Scott L; McGraw, Elizabeth A

    2009-09-15

    The mosquito Aedes aegypti was recently transinfected with a life-shortening strain of the endosymbiont Wolbachia pipientis (wMelPop) as the first step in developing a biocontrol strategy for dengue virus transmission. In addition to life-shortening, the wMelPop-infected mosquitoes also exhibit increased daytime activity and metabolic rates. Here we sought to quantify the blood-feeding behaviour of Wolbachia-infected females as an indicator of any virulence or energetic drain associated with Wolbachia infection. In a series of blood-feeding trials in response to humans, we have shown that Wolbachia-infected mosquitoes do not differ in their response time to humans, but that as they age they obtain fewer and smaller blood meals than Wolbachia-uninfected controls. Lastly, we observed a behavioural characteristic in the Wolbachia infected mosquitoes best described as a "bendy" proboscis that may explain the decreased biting success. Taken together the evidence suggests that wMelPop infection may be causing tissue damage in a manner that intensifies with mosquito age and that leads to reduced blood-feeding success. These behavioural changes require further investigation with respect to a possible physiological mechanism and their role in vectorial capacity of the insect. The selective decrease of feeding success in older mosquitoes may act synergistically with other Wolbachia-associated traits including life-shortening and viral protection in biocontrol strategies.

  11. Sustainable manufacture of insect repellents derived from Nepeta cataria.

    Science.gov (United States)

    Patience, Gregory S; Karirekinyana, Ginette; Galli, Federico; Patience, Nicolas A; Kubwabo, Cariton; Collin, Guy; Bizimana, Jean Claude; Boffito, Daria C

    2018-02-02

    Malaria devastates sub-Saharan Africa; the World Health Organization (WHO) estimates that 212 million people contract malaria annually and that the plasmodium virus will kill 419 000 in 2017. The disease affects rural populations who have the least economic means to fight it. Impregnated mosquito nets have reduced the mortality rate but the Anopheles mosquitoes are changing their feeding patterns and have become more active at dusk and early morning rather than after 22h00 as an adaptation to the nets. Everyone is susceptible to the Anopheles at these times but infants and pregnant women are the most vulnerable to the disease. Plant-based mosquito repellents are as effective as synthetic repellents that protect people from bites. They are sustainable preventative measures against malaria not only because of their efficacy but because the local population can produce and distribute them, which represents a source of economic growth for rural areas. Here, we extract and test the essential oil nepetalactone from Nepeta cataria via steam distillation. Families in endemic areas of Burundi found them effective against bites but commented that the odor was pungent. An epidemiological study is required to establish its clinical efficacy.

  12. Effect of Azolla feeding on the growth, feed conversion ratio, blood biochemical attributes and immune competence traits of growing turkeys

    Directory of Open Access Journals (Sweden)

    Mayank Shukla

    2018-04-01

    Full Text Available Background and Aim: In the recent past, few studies have been carried out in chicken to assess the effect of Azolla meal and raw Azolla feeding on the performance of chicken. If turkeys effectively use unconventional feedstuffs like Azolla without reducing the performance, it will increase the profitability of turkey business. Hence, a study was carried out to evaluate the effect of dried Azolla pinnata vis-a-vis raw Azolla as choice feeding on the growth, feed conversion ratio (FCR, blood biochemical attributes, and immune competence traits of growing turkeys under intensive system. Materials and Methods: A total of 72, 8-week-old grower turkey poults of black variety were randomly distributed into three dietary treatments having three replicates each with eight birds. The birds of the control group (T1 were fed a basal diet (CP - 19.71% and ME - 2789.79 Kcal/kg, while the other group (T2 and choice-feeding group (T3 were fed 5% of basal diet replaced by dry Azolla powder on DM basis and ad libitum Azolla along with basal diet, respectively. Results: There was no significant difference among the different groups in the average weekly weight gain during the entire experiment. FCR was significantly better (p<0.05 in the choice-feeding group compared to the other two experimental groups during 8-16 weeks of age. There was no significant difference among the treatment groups in any of the blood biochemical indices except plasma uric acid, which was significantly decreased (p<0.01 in T2 compared to T1 at 16 weeks of age. HA and IgM response to 1% sheep red blood cells (log2 titer were numerically better in T2 and T3 compared to the T1. Conclusion: Thus, it may be inferred that choice feeding with Azolla, and basal diet may improve FCR without any adverse effect on blood biochemical attributes and immune competence traits.

  13. Protection Ability Comparison of Several Mosquito Repellent Lotion Incorporated with Essential Oils of Mosquito Repellent Plants

    Directory of Open Access Journals (Sweden)

    Pramono Putro Utomo

    2014-12-01

    Full Text Available Most mosquito repellent lotions available on the market today contain the active ingredient diethyltoluamide (DEET which is very harmful to the skin. Natural mosquito repellent research using various essential oils (geranium oil, lemon oil, citronella oil and lavender oil as the active ingredient and the addition of aloe vera gel as a moisturizer has been done on a laboratory scale. The purpose of this study was to compare the protection ability of the mosquito repellent plants in Indonesia. The results showed that geranium oil, lemongrass oil, lavender oil and lemon oil could act as mosquito repellent. Best lotion formula all containing 15% essential oils have the effectiveness above 50% until the sixth hour were geranium oil, citronella oil and lavender oil while lemon oil only giving effectiveness above 50% until the second hour.

  14. Soil water repellency at old crude oil spill sites

    International Nuclear Information System (INIS)

    Roy, J.L.

    1999-08-01

    This thesis presents the current state of knowledge regarding the cause of soil water repellency and characterizes disaggregated nonwettable surface soils found at old crude oil spill sites. Pollution-induced water repellency generally develops following prolonged exposures of soil to liquid- or vapour-phase petroleum hydrocarbons. The condition varies significantly in terms of severity and persistence. Soil water repellency retards plant growth and disturbs the hydrological balance of ecosystems. Disaggregated water-repellent soils are also very susceptible to dispersal by erosion, posing a threat to the productivity of surrounding soils. The author described the probable causes of soil water repellency under the following three main themes: (1) accumulation of hydrophobic organic material in soil, (2) redistribution and re-organisation of this material in soil, and (3) stabilisation of the hydrophobic organic material. This final process is necessary to ensure persistence of induced water repellency symptoms. Petroleum residues as water-repellent substances in weathered nonwettable oil-contaminated soils were also discussed and a hypothesis about soil water repellency was presented which deals with flexible conformation in organic matter coatings. Processes leading to the development of soil water repellency following crude oil contamination were also described. It was determined that soil water repellency is a function of the packing density and the chain conformation of amphiphilic organic molecules in the outermost layer of soil organic matter coatings. This research suggests that the fractional coverage of alkyl chains on soil particle surfaces determines the degree of water repellency that is displayed by soil. It was shown that prompt remediation of some oil-contaminated plots can effectively prevent the development of soil water repellency. 4 refs., 32 tabs., 22 figs., 5 appendices

  15. Role of the blood-brain barrier in the evolution of feeding and cognition.

    Science.gov (United States)

    Banks, William A

    2012-08-01

    The blood-brain barrier (BBB) regulates the blood-to-brain passage of gastrointestinal hormones, thus informing the brain about feeding and nutritional status. Disruption of this communication results in dysregulation of feeding and body weight control. Leptin, which crosses the BBB to inform the CNS about adiposity, provides an example. Impaired leptin transport, especially coupled with central resistance, results in obesity. Various substances/conditions regulate leptin BBB transport. For example, triglycerides inhibit leptin transport. This may represent an evolutionary adaptation in that hypertriglyceridemia occurs during starvation. Inhibition of leptin, an anorectic, during starvation could have survival advantages. The large number of other substances that influence feeding is explained by the complexity of feeding. This complexity includes cognitive aspects; animals in the wild are faced with cost/benefit analyses to feed in the safest, most economical way. This cognitive aspect partially explains why so many feeding substances affect neurogenesis, neuroprotection, and cognition. The relation between triglycerides and cognition may be partially mediated through triglyceride's ability to regulate the BBB transport of cognitively active gastrointestinal hormones such as leptin, insulin, and ghrelin. © 2012 New York Academy of Sciences.

  16. Human Blood Feeding Activity of Female Hybrids between Culex pipiens pipiens and Culex pipiens quinquefasciatus(Diptera: Culicidae)

    OpenAIRE

    Yoshii, Manabu; Mine, Mariko; Kurokawa, Kenji; Oda, Tsutomu; Kato, Katsutomo; Ogawa, Yasunori; Eshita, Yuuki; Uchida, Keikichi

    2007-01-01

    Human blood feeding activity was examined in females of hybrids between Culex pipiens pipiens and Culex pipiens quinquefasciatus during long photoperiod at 25℃. Blood feeding rates of hybrids were lower than in Culex pipiens quinquefasciatus and Culex pipiens pallens, and higher than in Culex pipiens pipiens, because no females fed on human blood in Culex pipiens pipiens.

  17. Wolbachia infection reduces blood-feeding success in the dengue fever mosquito, Aedes aegypti.

    Directory of Open Access Journals (Sweden)

    Andrew P Turley

    Full Text Available BACKGROUND: The mosquito Aedes aegypti was recently transinfected with a life-shortening strain of the endosymbiont Wolbachia pipientis (wMelPop as the first step in developing a biocontrol strategy for dengue virus transmission. In addition to life-shortening, the wMelPop-infected mosquitoes also exhibit increased daytime activity and metabolic rates. Here we sought to quantify the blood-feeding behaviour of Wolbachia-infected females as an indicator of any virulence or energetic drain associated with Wolbachia infection. METHODOLOGY/PRINCIPAL FINDINGS: In a series of blood-feeding trials in response to humans, we have shown that Wolbachia-infected mosquitoes do not differ in their response time to humans, but that as they age they obtain fewer and smaller blood meals than Wolbachia-uninfected controls. Lastly, we observed a behavioural characteristic in the Wolbachia infected mosquitoes best described as a "bendy" proboscis that may explain the decreased biting success. CONCLUSIONS/SIGNIFICANCE: Taken together the evidence suggests that wMelPop infection may be causing tissue damage in a manner that intensifies with mosquito age and that leads to reduced blood-feeding success. These behavioural changes require further investigation with respect to a possible physiological mechanism and their role in vectorial capacity of the insect. The selective decrease of feeding success in older mosquitoes may act synergistically with other Wolbachia-associated traits including life-shortening and viral protection in biocontrol strategies.

  18. The influence of dengue virus serotype-2 infection on Aedes aegypti (Diptera: Culicidae motivation and avidity to blood feed.

    Directory of Open Access Journals (Sweden)

    Rafael Maciel-de-Freitas

    Full Text Available BACKGROUND: Dengue virus (DENV is transmitted by Aedes aegypti, a species that lives in close association with human dwellings. The behavior of DENV-infected mosquitoes needs further investigation, especially regarding the potential influence of DENV on mosquito biting motivation and avidity. METHODOLOGY/PRINCIPAL FINDINGS: We orally challenged 4-5 day-old Ae. aegypti females with a low passage DENV serotype -2 (DENV-2 to test whether the virus influences motivation to feed (the likelihood that a mosquito obtains a blood-meal and the size of its blood meal and avidity (the likelihood to re-feed after an interrupted first blood-meal. To assay motivation, we offered mosquitoes an anesthetized mouse for 2, 3, 4 or 5 minutes 7 or 14 days after the initial blood meals and measured the time they started feeding. 60.5% of the unexposed mosquitoes fed on the mouse, but only 40.5% of the positive ones did. Exposed but negative mosquitoes behaved similarly to unexposed ones (55.0% feeding. Thus DENV-2 infection decreased the mosquitoes' motivation to feed. To assay avidity, we offered the same mosquitoes a mouse two hours after the first round of feeding, and we measured the time at which they started probing. The exposed (positive or negative mosquitoes were more likely to re-feed than the unexposed ones and, in particular, the size of the previous blood-meal that kept mosquitoes from re-feeding was larger in the exposed than in the unexposed mosquitoes. Thus, DENV-2 infection increased mosquito avidity. CONCLUSIONS/SIGNIFICANCE: DENV-2 significantly decreased the mosquitoes' motivation to feed, but increased their avidity (even after taking account the amount of blood previously imbibed. As these are important components of transmission, we expect that the changes of the blood-feeding behaviour impact the vectorial capacity Ae. aegypti for dengue.

  19. The influence of dengue virus serotype-2 infection on Aedes aegypti (Diptera: Culicidae) motivation and avidity to blood feed.

    Science.gov (United States)

    Maciel-de-Freitas, Rafael; Sylvestre, Gabriel; Gandini, Mariana; Koella, Jacob C

    2013-01-01

    Dengue virus (DENV) is transmitted by Aedes aegypti, a species that lives in close association with human dwellings. The behavior of DENV-infected mosquitoes needs further investigation, especially regarding the potential influence of DENV on mosquito biting motivation and avidity. We orally challenged 4-5 day-old Ae. aegypti females with a low passage DENV serotype -2 (DENV-2) to test whether the virus influences motivation to feed (the likelihood that a mosquito obtains a blood-meal and the size of its blood meal) and avidity (the likelihood to re-feed after an interrupted first blood-meal). To assay motivation, we offered mosquitoes an anesthetized mouse for 2, 3, 4 or 5 minutes 7 or 14 days after the initial blood meals and measured the time they started feeding. 60.5% of the unexposed mosquitoes fed on the mouse, but only 40.5% of the positive ones did. Exposed but negative mosquitoes behaved similarly to unexposed ones (55.0% feeding). Thus DENV-2 infection decreased the mosquitoes' motivation to feed. To assay avidity, we offered the same mosquitoes a mouse two hours after the first round of feeding, and we measured the time at which they started probing. The exposed (positive or negative) mosquitoes were more likely to re-feed than the unexposed ones and, in particular, the size of the previous blood-meal that kept mosquitoes from re-feeding was larger in the exposed than in the unexposed mosquitoes. Thus, DENV-2 infection increased mosquito avidity. DENV-2 significantly decreased the mosquitoes' motivation to feed, but increased their avidity (even after taking account the amount of blood previously imbibed). As these are important components of transmission, we expect that the changes of the blood-feeding behaviour impact the vectorial capacity Ae. aegypti for dengue.

  20. Field Method for Testing Repellency of an Icaridin-Containing Skin Lotion against Vespid Wasps

    Directory of Open Access Journals (Sweden)

    Jean-Luc Boevé

    2016-06-01

    Full Text Available Vespid wasps are ecologically beneficial predators of insects but their stings also pose a human health risk. Current control methods based on killing vespids are suboptimal. Here, the repellent effect against Vespula vulgaris of a 20% icaridin skin lotion was evaluated under field conditions. An experimental setup was designed in which six artificial skin pieces (10 × 10 cm were video-recorded for 1 h, to count each min the numbers of flying and feeding vespids. Prior to monitoring, five pieces were successively smeared with 2 mg of cream per cm2, in 30 min intervals, from t = −120 min to 0. The sixth sheet remained untreated to serve as a control. One milliliter of an attractant, fruit jam, was deposited on each of the six surfaces at t = 0. The control surface was free of any flying or feeding vespid during an average period of 25 min, whereas the other five surfaces (treated at t = −120, −90, −60, −30, and 0 min remained vespid-free for 39, 40, 45, 49, and 51 min, respectively. The skin lotion remained significantly active for at least 2 h. The experimental methodology is adjustable and allows the study of repellents against vespids in semi-natural conditions.

  1. Evolution of the salivary apyrases of blood-feeding arthropods.

    Science.gov (United States)

    Hughes, Austin L

    2013-09-15

    Phylogenetic analyses of three families of arthropod apyrases were used to reconstruct the evolutionary relationships of salivary-expressed apyrases, which have an anti-coagulant function in blood-feeding arthropods. Members of the 5'nucleotidase family were recruited for salivary expression in blood-feeding species at least five separate times in the history of arthropods, while members of the Cimex-type apyrase family have been recruited at least twice. In spite of these independent events of recruitment for salivary function, neither of these families showed evidence of convergent amino acid sequence evolution in salivary-expressed members. On the contrary, in the 5'-nucleotide family, salivary-expressed proteins conserved ancestral amino acid residues to a significantly greater extent than related proteins without salivary function, implying parallel evolution by conservation of ancestral characters. This unusual pattern of sequence evolution suggests the hypothesis that purifying selection favoring conservation of ancestral residues is particularly strong in salivary-expressed members of the 5'-nucleotidase family of arthropods because of constraints arising from expression within the vertebrate host. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Visualizing non infectious and infectious Anopheles gambiae blood feedings in naive and saliva-immunized mice.

    Directory of Open Access Journals (Sweden)

    Valerie Choumet

    Full Text Available BACKGROUND: Anopheles gambiae is a major vector of malaria and lymphatic filariasis. The arthropod-host interactions occurring at the skin interface are complex and dynamic. We used a global approach to describe the interaction between the mosquito (infected or uninfected and the skin of mammals during blood feeding. METHODS: Intravital video microscopy was used to characterize several features during blood feeding. The deposition and movement of Plasmodium berghei sporozoites in the dermis were also observed. We also used histological techniques to analyze the impact of infected and uninfected feedings on the skin cell response in naive mice. RESULTS: The mouthparts were highly mobile within the skin during the probing phase. Probing time increased with mosquito age, with possible effects on pathogen transmission. Repletion was achieved by capillary feeding. The presence of sporozoites in the salivary glands modified the behavior of the mosquitoes, with infected females tending to probe more than uninfected females (86% versus 44%. A white area around the tip of the proboscis was observed when the mosquitoes fed on blood from the vessels of mice immunized with saliva. Mosquito feedings elicited an acute inflammatory response in naive mice that peaked three hours after the bite. Polynuclear and mast cells were associated with saliva deposits. We describe the first visualization of saliva in the skin by immunohistochemistry (IHC with antibodies directed against saliva. Both saliva deposits and sporozoites were detected in the skin for up to 18 h after the bite. CONCLUSION: This study, in which we visualized the probing and engorgement phases of Anopheles gambiae blood meals, provides precise information about the behavior of the insect as a function of its infection status and the presence or absence of anti-saliva antibodies. It also provides insight into the possible consequences of the inflammatory reaction for blood feeding and pathogen

  3. Visualizing non infectious and infectious Anopheles gambiae blood feedings in naive and saliva-immunized mice.

    Science.gov (United States)

    Choumet, Valerie; Attout, Tarik; Chartier, Loïc; Khun, Huot; Sautereau, Jean; Robbe-Vincent, Annie; Brey, Paul; Huerre, Michel; Bain, Odile

    2012-01-01

    Anopheles gambiae is a major vector of malaria and lymphatic filariasis. The arthropod-host interactions occurring at the skin interface are complex and dynamic. We used a global approach to describe the interaction between the mosquito (infected or uninfected) and the skin of mammals during blood feeding. Intravital video microscopy was used to characterize several features during blood feeding. The deposition and movement of Plasmodium berghei sporozoites in the dermis were also observed. We also used histological techniques to analyze the impact of infected and uninfected feedings on the skin cell response in naive mice. The mouthparts were highly mobile within the skin during the probing phase. Probing time increased with mosquito age, with possible effects on pathogen transmission. Repletion was achieved by capillary feeding. The presence of sporozoites in the salivary glands modified the behavior of the mosquitoes, with infected females tending to probe more than uninfected females (86% versus 44%). A white area around the tip of the proboscis was observed when the mosquitoes fed on blood from the vessels of mice immunized with saliva. Mosquito feedings elicited an acute inflammatory response in naive mice that peaked three hours after the bite. Polynuclear and mast cells were associated with saliva deposits. We describe the first visualization of saliva in the skin by immunohistochemistry (IHC) with antibodies directed against saliva. Both saliva deposits and sporozoites were detected in the skin for up to 18 h after the bite. This study, in which we visualized the probing and engorgement phases of Anopheles gambiae blood meals, provides precise information about the behavior of the insect as a function of its infection status and the presence or absence of anti-saliva antibodies. It also provides insight into the possible consequences of the inflammatory reaction for blood feeding and pathogen transmission.

  4. Notes on the blood-feeding behavior of Aedes albopictus (Diptera: Culicidae in Cameroon

    Directory of Open Access Journals (Sweden)

    Kamgang Basile

    2012-03-01

    Full Text Available Abstract Background The invasive mosquito Aedes albopictus is often considered a poor vector of human pathogens, owing to its catholic feeding behavior. However, it was recently incriminated as a major vector in several Chikungunya epidemics, outside of its native range. Here we assessed two key elements of feeding behavior by Ae. albopictus females in Yaoundé, Cameroon, Central Africa. Host preference was explored and the human-biting activity of females was monitored over 24 h to determine periods of maximum bite exposure. Findings Analysis of ingested blood in outdoor-resting females showed that Ae. albopictus preferentially fed on humans rather than on available domestic animals (95% of the blood meals contained human blood. Our results further showed that Ae. albopictus is a day-biting species in Yaoundé, with a main peak of activity in the late afternoon. Conclusion This is the first report on the feeding behavior of Ae. albopictus in Central Africa. The species is highly aggressive to humans and might therefore be involved in human-human virus transmission in this setting.

  5. Notes on the blood-feeding behavior of Aedes albopictus (Diptera: Culicidae) in Cameroon.

    Science.gov (United States)

    Kamgang, Basile; Nchoutpouen, Elysée; Simard, Frédéric; Paupy, Christophe

    2012-03-21

    The invasive mosquito Aedes albopictus is often considered a poor vector of human pathogens, owing to its catholic feeding behavior. However, it was recently incriminated as a major vector in several Chikungunya epidemics, outside of its native range. Here we assessed two key elements of feeding behavior by Ae. albopictus females in Yaoundé, Cameroon, Central Africa. Host preference was explored and the human-biting activity of females was monitored over 24 h to determine periods of maximum bite exposure. Analysis of ingested blood in outdoor-resting females showed that Ae. albopictus preferentially fed on humans rather than on available domestic animals (95% of the blood meals contained human blood). Our results further showed that Ae. albopictus is a day-biting species in Yaoundé, with a main peak of activity in the late afternoon. This is the first report on the feeding behavior of Ae. albopictus in Central Africa. The species is highly aggressive to humans and might therefore be involved in human-human virus transmission in this setting.

  6. Mosquito repellent activity of piper guineense and xylopia ...

    African Journals Online (AJOL)

    The activity of eucalyptus oil (positive control), a commercial repellent, at 30% was only able to protect for 2h. Both oils used could be applied as repellents where protection from mosquito bite is sought for, over a short period of time. Keywords: Piper guineense, Xylopia aethiopica, volatile oils, Aedes aegypti, repellency

  7. Limitation of using synthetic human odours to test mosquito repellents

    Directory of Open Access Journals (Sweden)

    Mbeyela Edgar

    2009-07-01

    Full Text Available Abstract Background Gold-standard tests of mosquito repellents involve exposing human volunteers to host-seeking mosquitoes, to assess the protective efficacy of the repellents. These techniques are not exposure-free and cannot be performed prior to toxicological evaluation. It is postulated that synthetic lures could provide a useful assay that mimics in-vivo conditions for use in high-throughput screening for mosquito repellents. Methods This paper reports on a semi-field evaluation of repellents using a synthetic blend of human derived attractants for the malaria vector, Anopheles gambiae sensu stricto Different concentrations of known repellents, N, N diethyl-3-methylbenzamide (deet and Para-methane-3, 8, diol (PMD were added into traps baited with the synthetic blend, and resulting changes in mosquito catches were measured. Results All test concentrations of deet (0.001% to 100% reduced the attractiveness of the synthetic blend. However, PMD was repellent only at 0.25%. Above this concentration, it significantly increased the attractiveness of the blend. There was no relationship between the repellent concentrations and the change in mosquito catches when either deet (r2 = 0.033, P = 0.302 or PMD (r2 = 0.020, P = 0.578 was used. Conclusion It is concluded that while some repellents may reduce the attractiveness of synthetic human odours, others may instead increase their attractiveness. Such inconsistencies indicate that even though the synthetic attractants may provide exposure-free and consistent test media for repellents, careful selection and multiple-repellent tests are necessary to ascertain their suitability for use in repellent screening. The synthetic odour blend tested here is not yet sufficiently refined to serve as replacement for humans in repellent testing, but may be developed further and evaluated in different formats for exposure free repellent testing purposes.

  8. Water repellent soils: a state-of-the-art

    Science.gov (United States)

    Leonard F. DeBano

    1981-01-01

    Water repellency in soils was first described by Schreiner and Shorey (1910), who found that some soils in California could not be wetted and thereby were not suitable for agriculture. Waxy organic substances were responsible for the water repellency. Other studies in the early 1900's on the fairy ring phenomenon suggested that water repellency could be caused by...

  9. The entomopathogenic fungus Beauveria bassiana reduces instantaneous blood feeding in wild multi-insecticide-resistant Culex quinquefasciatus mosquitoes in Benin, West Africa

    Directory of Open Access Journals (Sweden)

    Howard Annabel FV

    2010-09-01

    Full Text Available Abstract Background Mosquito-borne diseases are still a major health risk in many developing countries, and the emergence of multi-insecticide-resistant mosquitoes is threatening the future of vector control. Therefore, new tools that can manage resistant mosquitoes are required. Laboratory studies show that entomopathogenic fungi can kill insecticide-resistant malaria vectors but this needs to be verified in the field. Methods The present study investigated whether these fungi will be effective at infecting, killing and/or modifying the behaviour of wild multi-insecticide-resistant West African mosquitoes. The entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana were separately applied to white polyester window netting and used in combination with either a permethrin-treated or untreated bednet in an experimental hut trial. Untreated nets were used because we wanted to test the effect of fungus alone and in combination with an insecticide to examine any potential additive or synergistic effects. Results In total, 1125 female mosquitoes were collected during the hut trial, mainly Culex quinquefasciatus Say. Unfortunately, not enough wild Anopheles gambiae Giles were collected to allow the effect the fungi may have on this malaria vector to be analysed. None of the treatment combinations caused significantly increased mortality of Cx. quinquefasciatus when compared to the control hut. The only significant behaviour modification found was a reduction in blood feeding by Cx. quinquefasciatus, caused by the permethrin and B. bassiana treatments, although no additive effect was seen in the B. bassiana and permethrin combination treatment. Beauveria bassiana did not repel blood foraging mosquitoes either in the laboratory or field. Conclusions This is the first time that an entomopathogenic fungus has been shown to reduce blood feeding of wild mosquitoes. This behaviour modification indicates that B. bassiana could potentially be a new

  10. Effect of photoperiod on blood feeding activity of female hybrids between Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae)

    OpenAIRE

    Kurokawa, Kenji; Yoshii, Manabu; Oda, Tsutomu; Kato, Katsutomo; Uchida, Keikichi; Eshita, Yuki; Tahara, Hiroyuki; Mine, Mariko; Ogawa, Yasunori

    2004-01-01

    Blood feeding activity was examined in females of hybrids (F1) between Culex pipiens pipiens and Culex pipiens quinquefasciatus in long and short photoperiods at 2l℃ to examine the effect of photoperiod on blood feeding rate. Blood feeding rates (F1) were lower in short photoperiods than in long photoperiods. From this, it seems that the hybrids show diapause.

  11. A Fat strange Repeller

    Institute of Scientific and Technical Information of China (English)

    申影; 何阅; 姜玉梅; 何大韧

    2004-01-01

    This article reports an observation on a fat strange repeller, which appears after a characteristic crisis observed in a kicked rotor subjected to a piecewise continuous force field. The discontinuity border in the definition range of the two-dimensional mapping, which describes the system, oscillates as the discrete time develops. At a threshold of a control parameter a fat chaotic attractor suddenly transfers to a fat transient set. The strange repeller, which appears after the crisis, is also a fat fractal. This is the reason why super-transience happens

  12. Effect of By-product Feed-based Silage Feeding on the Performance, Blood Metabolites, and Carcass Characteristics of Hanwoo Steers (a Field Study).

    Science.gov (United States)

    Kim, Y I; Park, J M; Lee, Y H; Lee, M; Choi, D Y; Kwak, W S

    2015-02-01

    This study was conducted to determine the effects of feeding by-product feed (BF)-based silage on the performance, blood metabolite parameters, and carcass characteristics of Hanwoo steers. The BF-based silage was composed of 50% spent mushroom substrate, 21% recycled poultry bedding, 15% cut ryegrass straw, 10.8% rice bran, 2% molasses, 0.6% bentonite, and 0.6% microbial additive (on a wet basis), and ensiled for over 5 d. Fifteen steers were allocated to three diets during the growing and fattening periods (3.1 and 9.8 months, respectively): a control diet (concentrate mix and free access to rice straw), a 50% BF-based silage diet (control diet+50% of maximum BF-based silage intake), and a 100% BF-based silage diet (the same amount of concentrate mix and ad libitum BF-based silage). The BF-based silage was fed during the growing and fattening periods, and was replaced with larger particles of rice straw during the finishing period. After 19.6 months of the whole period all the steers were slaughtered. Compared with feeding rice straw, feeding BF-based silage tended (p = 0.10) to increase the average daily gain (27%) and feed efficiency (18%) of the growing steers, caused by increased voluntary feed intake. Feeding BF-based silage had little effect on serum constituents, electrolytes, enzymes, or the blood cell profiles of fattening steers, except for low serum Ca and high blood urea concentrations (p<0.05). Feeding BF-based silage did not affect cold carcass weight, yield traits such as back fat thickness, longissimus muscle area, yield index or yield grade, or quality traits such as meat color, fat color, texture, maturity, marbling score, or quality grade. However, it improved good quality grade (1(+) and 1(++)) appearance rates (60% for the control group vs 100% for the BF-based silage-fed groups). In conclusion, cheap BF-based silage could be successfully used as a good quality roughage source for beef cattle.

  13. Dimension of non-conformal repellers: a survey

    International Nuclear Information System (INIS)

    Chen, Jianyu; Pesin, Yakov

    2010-01-01

    This paper is a survey of recent results on the dimension of repellers for expanding maps and limit sets for iterated function systems. While the case of conformal repellers is well understood, the study of non-conformal repellers is in its early stages though a number of interesting phenomena have been discovered, some remarkable results obtained and several interesting examples constructed. We will describe contemporary state of the art in the area with emphasis on some new emerging ideas and open problems. (invited article)

  14. The role of cystatins in tick physiology and blood feeding

    Czech Academy of Sciences Publication Activity Database

    Schwarz, Alexandra; Valdés, James J.; Kotsyfakis, Michalis

    2012-01-01

    Roč. 3, č. 3 (2012), s. 117-127 ISSN 1877-959X R&D Projects: GA ČR GAP502/12/2409 Institutional research plan: CEZ:AV0Z60220518 Keywords : Cystatin * Cysteine proteases * Tick * Immunomodulators * Blood feeding * Midgut * Physiology Subject RIV: EC - Immunology Impact factor: 2.353, year: 2012

  15. Moisture variability resulting from water repellency in Dutch soils

    NARCIS (Netherlands)

    Dekker, L.W.

    1998-01-01

    The present study suggests that many soils in the Netherlands, in natural as well as in agricultural areas, may be water repellent to some degree, challenging the common perception that soil water repellency is only an interesting aberration. When dry, water repellent soils resist or retard

  16. Evaporation and skin penetration characteristics of mosquito repellent formulations

    International Nuclear Information System (INIS)

    Reifenrath, W.G.; Hawkins, G.S.; Kurtz, M.S.

    1989-01-01

    Formulations of the mosquito repellent N,N-diethyl-3-methylbenzamide (deet) in combination with a variety of additives were developed to control repellent evaporation and percutaneous penetration. Deet was also formulated with the repellent dimethyl phthalate to study the interaction of the two compounds on the skin. The evaporation and penetration processes were evaluated on whole and split-thickness pig skin using radiolabeled repellents with an in vitro apparatus. Under essentially still air and air flow conditions, one of the deet formulations resulted in significantly reduced total evaporation and percutaneous penetration of deet as compared to unformulated repellent. When deet and dimethyl phthalate were combined, neither repellent affected the total amount of evaporation and penetration of the other compound. However, initial percutaneous penetration and evaporation rates were slightly less and decayed less rapidly than when both chemicals were tested separately at the same dose. These results indicated a degree of competition of the two compounds for the same avenues of loss

  17. Comparative studies on the biology and filarial susceptibility of selected blood-feeding and autogenous Aedes togoi sub-colonies

    Directory of Open Access Journals (Sweden)

    Anuluck Junkum

    2003-06-01

    Full Text Available Blood-feeding and autogenous sub-colonies were selected from a laboratory, stock colony of Aedes togoi, which was originally collected from Koh Nom Sao, Chanthaburi province, Southeast Thailand. Comparative biology and filarial susceptibility between the two sub-colonies (blood-feeding: F11, F13; autogeny: F38, F40 were investigated to evaluate their viability and vectorial capacity. The results of comparison on biology revealed intraspecific differences, i.e., the average egg deposition/gravid female (F11/F38; F13/F40, embryonation rate (F13/F40, hatchability rate (F11/F38; F13/F40, egg width (F11/F38, wing length of females (F13/F40, and wing length and width of males (F11/F38 in the blood-feeding sub-colony were significantly greater than that in the autogenous sub-colony; and egg length (F11/F38 and width (F13/F40, and mean longevity of adult females (F11/F38 and males (F13/F40 in the blood-feeding sub-colony were significantly less than that in the autogenous sub-colony. The results of comparison on filarial susceptibility demonstrated that both sub-colonies yielded similar susceptibilities to Brugia malayi [blood-feeding/autogeny = 56.7% (F11/53.3%(F38, 60%(F13/83.3%(F40] and Dirofilaria immitis [blood-feeding/autogeny = 85.7%(F11/75%(F38, 45%(F13/29.4%(F40], suggesting autogenous Ae. togoi sub-colony was an efficient laboratory vector in study of filariasis.

  18. Pest repelling properties of ant pheromones

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    2014-01-01

    Ants control pests via predation and physical deterrence; however, ant communication is based on chemical cues which may serve as warning signals to potential prey and other intruders. The presence of ant pheromones may, thus, be sufficient to repel pests from ant territories. This mini-review sh......-review shows that four out of five tested ant species deposit pheromones that repel herbivorous prey from their host plants.......Ants control pests via predation and physical deterrence; however, ant communication is based on chemical cues which may serve as warning signals to potential prey and other intruders. The presence of ant pheromones may, thus, be sufficient to repel pests from ant territories. This mini...

  19. Effect of Azolla feeding on the growth, feed conversion ratio, blood biochemical attributes and immune competence traits of growing turkeys.

    Science.gov (United States)

    Shukla, Mayank; Bhattacharyya, Amitav; Shukla, Pankaj Kumar; Roy, Debashis; Yadav, Brijesh; Sirohi, Rajneesh

    2018-04-01

    In the recent past,few studies have been carried out in chicken to assess the effect of Azolla meal and raw Azolla feeding on the performance of chicken. If turkeys effectively use unconventional feedstuffs like Azolla without reducing the performance, it will increase the profitability of turkey business. Hence, a study was carried out to evaluate the effect of dried Azolla pinnata vis-a-vis raw Azolla as choice feeding on the growth, feed conversion ratio (FCR), blood biochemical attributes, and immune competence traits of growing turkeys under intensive system. A total of 72, 8-week-old grower turkey poults of black variety were randomly distributed into three dietary treatments having three replicates each with eight birds. The birds of the control group (T1) were fed a basal diet (CP - 19.71% and ME - 2789.79 Kcal/kg), while the other group (T2) and choice-feeding group (T3) were fed 5% of basal diet replaced by dry Azolla powder on DM basis and ad libitumAzolla along with basal diet, respectively. There was no significant difference among the different groups in the average weekly weight gain during the entire experiment. FCR was significantly better (pdiet may improve FCR without any adverse effect on blood biochemical attributes and immune competence traits.

  20. Repellency Effect of Essential Oils of Some Native Plants and Synthetic Repellents against Human Flea, Pulex irritans (Siphonaptera: Pulicidae

    Directory of Open Access Journals (Sweden)

    Mohammad Bagher Ghavami

    2017-04-01

    Full Text Available Background: Fleas are important vectors of human and animal disease, and control measures for protection against their bites and flea-borne diseases are necessary.Methods: The essential oils (EOs of four native medicinal plants, Ziziphora tenuiore, Myrtus communis, Achillea wilhelmsii and Mentha piperita were isolated by hydrodistillation technique and analyzed by GC-MC. The repellent activity of EOs and synthetic compounds, DEET and permethrin, were assayed on human subjects against field col­lected fleas. The effective doses of 50% and 90% of EOs and synthetic compounds were estimated by probit analysis of dose and response regression line.Results: Analysis of EOs revealed about 19 major components. All oils were found to be more repellent (ED50 range= 208–955µg cm-2 than DEET and permethrin (ED50 range= 27–182 x 103 µg cm-2. Thyme and myrtle oils showed high repellent activities and among the total detected terpenes, thymol (36.26% and α- pinene (32.5% were the major components of those oils respectively.Conclusion: Low repellent potency of DEET and permethrin against fleas might be related to flea olfactory system and further molecular and electrophysiological studies are required to conceive new ideas for the discovery and de­velopment of the next generation of repellents. Based on high repellent activity of thyme and myrtle essential oils against Pulex irritans further studies should be staged to develop their appropriate effective formulations. Likewise, field trials should be carried out to evaluate the operational feasibility and dermal toxicity over a long period.

  1. Toxicity of a plant based mosquito repellent/killer

    Science.gov (United States)

    Singh, Prakash Raj; Mohanty, Manoj Kumar

    2012-01-01

    The mission to make humans less attractive to mosquitoes has fuelled decades of scientific research on mosquito behaviour and control. The search for the perfect topical insect repellent/killer continues. This analysis was conducted to review and explore the scientific information on toxicity produced by the ingredients/contents of a herbal product. In this process of systemic review the following methodology was applied. By doing a MEDLINE search with key words of selected plants, plant based insect repellents/killers pertinent articles published in journals and authentic books were reviewed. The World Wide Web and the Extension Toxicity Network database (IPCS-ITOX) were also searched for toxicology data and other pertinent information. Repellents do not all share a single mode of action and surprisingly little is known about how repellents act on their target insects. Moreover, different mosquito species may react differently to the same repellent. After analysis of available data and information on the ingredient, of the product in relation to medicinal uses, acute and chronic toxicity of the selected medicinal plants, it can be concluded that the ingredients included in the herbal product can be used as active agents against mosquitoes. If the product which contains the powder of the above said plants is applied with care and safety, it is suitable fo use as a mosquito repellent/killer. PMID:23554562

  2. Greenland shark (Somniosus microcephalus) feeding behavior on static fishing gear, effect of SMART (Selective Magnetic and Repellent-Treated) hook deterrent technology, and factors influencing entanglement in bottom longlines

    Science.gov (United States)

    Sullivan, Rennie; Hedges, Kevin J.

    2018-01-01

    The Greenland Shark (Somniosus microcephalus) is the most common bycatch in the Greenland halibut (Reinhardtius hippoglossoides) bottom longline fishery in Cumberland Sound, Canada. Historically, this inshore fishery has been prosecuted through the ice during winter but winter storms and unpredictable landfast ice conditions since the mid-1990s have led to interest in developing a summer fishery during the ice-free season. However, bycatch of Greenland shark was found to increase substantially with 570 sharks captured during an experimental Greenland halibut summer fishery (i.e., mean of 6.3 sharks per 1,000 hooks set) and mortality was reported to be about 50% due in part to fishers killing sharks that were severely entangled in longline gear. This study investigated whether the SMART (Selective Magnetic and Repellent-Treated) hook technology is a practical deterrent to Greenland shark predation and subsequent bycatch on bottom longlines. Greenland shark feeding behavior, feeding kinematics, and variables affecting entanglement/disentanglement and release are also described. The SMART hook failed to deter Greenland shark predation, i.e., all sharks were captured on SMART hooks, some with more than one SMART hook in their jaw. Moreover, recently captured Greenland sharks did not exhibit a behavioral response to SMART hooks. In situ observations of Greenland shark feeding show that this species uses a powerful inertial suction mode of feeding and was able to draw bait into the mouth from a distance of 25–35 cm. This method of feeding is suggested to negate the potential deterrent effects of electropositive metal and magnetic alloy substitutions to the SMART hook technology. The number of hooks entangled by a Greenland shark and time to disentangle and live-release a shark was found to increase with body length.

  3. Greenland shark (Somniosus microcephalus) feeding behavior on static fishing gear, effect of SMART (Selective Magnetic and Repellent-Treated) hook deterrent technology, and factors influencing entanglement in bottom longlines.

    Science.gov (United States)

    Grant, Scott M; Sullivan, Rennie; Hedges, Kevin J

    2018-01-01

    The Greenland Shark ( Somniosus microcephalus ) is the most common bycatch in the Greenland halibut ( Reinhardtius hippoglossoides ) bottom longline fishery in Cumberland Sound, Canada. Historically, this inshore fishery has been prosecuted through the ice during winter but winter storms and unpredictable landfast ice conditions since the mid-1990s have led to interest in developing a summer fishery during the ice-free season. However, bycatch of Greenland shark was found to increase substantially with 570 sharks captured during an experimental Greenland halibut summer fishery (i.e., mean of 6.3 sharks per 1,000 hooks set) and mortality was reported to be about 50% due in part to fishers killing sharks that were severely entangled in longline gear. This study investigated whether the SMART (Selective Magnetic and Repellent-Treated) hook technology is a practical deterrent to Greenland shark predation and subsequent bycatch on bottom longlines. Greenland shark feeding behavior, feeding kinematics, and variables affecting entanglement/disentanglement and release are also described. The SMART hook failed to deter Greenland shark predation, i.e., all sharks were captured on SMART hooks, some with more than one SMART hook in their jaw. Moreover, recently captured Greenland sharks did not exhibit a behavioral response to SMART hooks. In situ observations of Greenland shark feeding show that this species uses a powerful inertial suction mode of feeding and was able to draw bait into the mouth from a distance of 25-35 cm. This method of feeding is suggested to negate the potential deterrent effects of electropositive metal and magnetic alloy substitutions to the SMART hook technology. The number of hooks entangled by a Greenland shark and time to disentangle and live-release a shark was found to increase with body length.

  4. Repellents inhibit P450 enzymes in Stegomyia (Aedes aegypti.

    Directory of Open Access Journals (Sweden)

    Gloria Isabel Jaramillo Ramirez

    Full Text Available The primary defence against mosquitoes and other disease vectors is often the application of a repellent. Despite their common use, the mechanism(s underlying the activity of repellents is not fully understood, with even the mode of action of DEET having been reported to be via different mechanisms; e.g. interference with olfactory receptor neurones or actively detected by olfactory receptor neurones on the antennae or maxillary palps. In this study, we discuss a novel mechanism for repellence, one of P450 inhibition. Thirteen essential oil extracts from Colombian plants were assayed for potency as P450 inhibitors, using a kinetic fluorometric assay, and for repellency using a modified World Health Organisation Pesticide Evaluations Scheme (WHOPES arm-in cage assay with Stegomyia (Aedes aegypti mosquitoes. Bootstrap analysis on the inhibition analysis revealed a significant correlation between P450-inhibition and repellent activity of the oils.

  5. SHORT COMMUNICATION Repellency property of long chain ...

    African Journals Online (AJOL)

    Repellency property of long chain aliphatic methyl ketones against Anopheles gambiae s.s ... tained from huge diversity of plant species are an important source of safe .... dry and then introduced with the hand covered by a glove in .... citronellal in repelling bees from basil (Oci- ... Journal of American Mosquito Control As-.

  6. High activity enables life on a high-sugar diet : blood glucose regulation in nectar-feeding bats

    NARCIS (Netherlands)

    Kelm, Detlev H; Simon, Ralph; Kuhlow, Doreen; Voigt, Christian C; Ristow, Michael

    2011-01-01

    High blood glucose levels caused by excessive sugar consumption are detrimental to mammalian health and life expectancy. Despite consuming vast quantities of sugar-rich floral nectar, nectar-feeding bats are long-lived, provoking the question of how they regulate blood glucose. We investigated blood

  7. Insect Repellents: Protect Your Child from Insect Bites

    Science.gov (United States)

    ... Español Text Size Email Print Share Choosing an Insect Repellent for Your Child Page Content Mosquitoes, biting ... sunscreen needs to be reapplied often. Reactions to Insect Repellents If you suspect that your child is ...

  8. Toxicity, tunneling and feeding behavior of the termite, Coptotermes vastator, in sand treated with oil of the physic nut, Jatropha curcas.

    Science.gov (United States)

    Acda, Menandro N

    2009-01-01

    Oil of the physic nut, Jatropha curcas L. (Malpighiales: Euphorbiaceae), was evaluated in the laboratory for its barrier and repellent activity against the Philippine milk termite Coptotermes vastator Light (Isoptera: Rhinotermitidae). The study showed that J. curcas oil had anti-feeding effect, induced reduction in tunneling activity and increased mortality in C. vastator. Behavior of termites exposed to sand treated with J. curcas oil indicated that it is toxic or repellent to C. vastator. Toxicity and repellent thresholds, were higher than those reported for other naturally occurring compounds tested against the Formosan subterranean termite.

  9. EPA-Registered Repellents for Mosquitoes Transmitting Emerging Viral Disease.

    Science.gov (United States)

    Patel, Radha V; Shaeer, Kristy M; Patel, Pooja; Garmaza, Aleksey; Wiangkham, Kornwalee; Franks, Rachel B; Pane, Olivia; Carris, Nicholas W

    2016-12-01

    In many parts of the United States, mosquitoes were previously nuisance pests. However, they now represent a potential threat in the spread of viral diseases. The Aedes aegypti, Aedes albopictus, and Culex species mosquitoes are endemic to the United States and together may transmit a variety of viral diseases of growing concern, including West Nile virus, chikungunya, dengue fever, and Zika virus. The Centers for Disease Control and Prevention and the Environmental Protection Agency (EPA) recommend N,N-diethyl-meta-toluamide (DEET) as a first-line mosquito repellent, but for patients refusing to use DEET or other conventional repellents, guidance is limited to any EPA-registered product. Therefore, we conducted a systematic review of the literature to identify which EPA-registered personal mosquito repellent provides the best protection from A. aegypti, A. albopictus, and Culex spp. mosquitoes. We abstracted data from 62 published reports of EPA-registered mosquito repellents. The conventional repellent picaridin has the strongest data to support its use as a second-line agent, while IR3535 and oil of lemon eucalyptus are reasonably effective natural products. Citronella, catnip, and 2-undecanone offer limited protection or have limited data. These results can be used by pharmacists and other health care professionals to advise patients on the selection of an EPA-registered mosquito repellent. Regardless of the repellent chosen, it is vital for patients to follow all instructions/precautions in the product labeling to ensure safe and effective use. © 2016 Pharmacotherapy Publications, Inc.

  10. The Effects of Pre-Exposure to DEET on the Downstream Blood-Feeding Behaviors of Aedes aegypti Mosquitoes

    Science.gov (United States)

    2016-06-10

    1 Sugiharto et al.: Aedes aegypti blood- Michael J. Turell 1 feeding after DEET pre-exposure Virology Division, USAMRIID 2 1425 Porter...Pre-exposure to DEET on the Downstream Blood-Feeding Behaviors of 9 Aedes aegypti Mosquitoes1 10 11 Victor A. Sugiharto,2 John P. Grieco,2,3...insect behavior for disease prevention. However, genetic insensitivity and 31 habituation in Aedes aegypti (L.) mosquitoes after pre-exposure to DEET

  11. Water repellent soils: the case for unsaturated soil mechanics

    Directory of Open Access Journals (Sweden)

    Beckett Christopher

    2016-01-01

    Full Text Available Water repellent (or “hydrophobic” or “non-wetting” soils have been studied by soil scientists for well over a century. These soils are typified by poor water infiltration, which leads to increased soil erosion and poor crop growth. However, the importance of water repellence on determining soil properties is now becoming recognised by geotechnical engineers. Water repellent soils may, for example, offer novel solutions for the design of cover systems overlying municipal or mine waste storage facilities. However, investigations into factors affecting their mechanical properties have only recently been initiated. This purpose of this paper is to introduce geotechnical engineers to the concept of water repellent soils and to discuss how their properties can be evaluated under an unsaturated soils framework. Scenarios in which water repellent properties might be relevant in geotechnical applications are presented and methods to quantify these properties in the laboratory and in the field examined.

  12. Repellent activities of dichloromethane extract of Allium sativum (garlic) (Liliaceae) against Hyalomma rufipes (Acari).

    Science.gov (United States)

    Nchu, Felix; Magano, Solomon R; Eloff, Jacobus N

    2016-12-02

    Dichloromethane (DCM) extract of garlic (Allium sativum Linn.) bulbs was assessed for its repellent effect against the hard tick, Hyalomma rufipes (Acari: Ixodidae) using two tick behavioural bioassays; Type A and Type B repellency bioassays, under laboratory conditions. These bioassays exploit the questing behaviour of H. rufipes, a tick that in nature displays ambush strategy, seeking its host by climbing up on vegetation and attaching to a passing host. One hundred microlitres (100 µL) of the test solution containing DCM extract of garlic bulbs and DCM at concentrations of 0.35%, 0.7% or 1.4% w/v were evaluated. DCM only was used for control. Tick repellency increased significantly (R2 = 0.98) with increasing concentration (40.03% - 86.96%) yielding an EC50 of 0.45% w/v in Type B repellency bioassay. At concentration of 1.4% w/v, the DCM extract of garlic bulbs produced high repellency index of 87% (male ticks) and 87.5% (female ticks) in the Type A repellency bioassay. Only 4% avoidance of male ticks or female ticks was recorded in the Type B repellency bioassay. In the corresponding controls, the mean numbers of non-repelled male or female ticks were 80% and 41 males or 38 females of 50 ticks in the Type A and Type B repellency bioassays, respectively. The variations in the results could be attributed to the difference in tick repellent behaviours that were assessed by the two repellency bioassays; the Type A repellency bioassay assessed repellent effect of garlic extracts without discriminating between deterrence and avoidance whereas the Type B repellency bioassay only assessed avoidance response. Generally, DCM extract of garlic was repellent against H. rufipes, albeit weak tick repellency was obtained in the Type B repellency bioassay. Furthermore, this study established that the tick repellent activity of garlic extracts is predominantly by deterrence.

  13. Glycerin in cattle feed: intake, digestibility, and ruminal and blood parameters

    Directory of Open Access Journals (Sweden)

    Vanessa Ruiz Fávaro

    2015-06-01

    Full Text Available This study aimed to evaluate the effects of glycerin supplements in the diet of beef cattle by assessing intake, apparent nutrient digestibility, ruminal pH, ruminal ammonia concentrations, and blood parameters. The study was conducted at the São Paulo State University (UNESP, Jaboticabal campus using five crossbred cattle in an experiment employing a 5 x 5 Latin square design. Cattle diet treatments included zero, 50, 100, 150, and 200 g kg-1 dry matter of glycerin. Feed, leftover feed, and faeces were collected to determine intake and digestibility. Samples of ruminal liquid were collected at –1, 0, 1, 2, 4, 6 and 8 h after feeding to determine pH and ruminal ammonia. Blood was collected four hours after the morning feeding from the coccygeal vein. Replacing maize with glycerin resulted in lower concentrations of ether extract and non-fibre carbohydrates in the diets, leading to a linear decrease in the intake of these nutrients (P<0.05. The digestibility of neutral detergent fibre and non-fibre carbohydrates also decreased linearly with increasing dietary glycerin concentrations (P<0.05. The results for ruminal fermentation parameters showed a linear decrease (P<0.05 in the ruminal concentration of N-NH3 with increasing dietary levels of glycerin; however, ruminal pH was not affected (P<0.05. Serum concentrations of urea, triglycerides, cholesterol, and plasma glucose concentrations were within normal ranges based on the literature. The inclusion of glycerin in the cattle diet altered rumen fermentation, reducing the concentration of N-NH 3, the digestibility of neutral detergent fiber and non-fiber carbohydrates.

  14. Proteolytic system of blood-feeding ticks: An update on protein structures

    Czech Academy of Sciences Publication Activity Database

    Kovářová, Zuzana; Hobizalová, Radka; Žebrakovská, Iva; Brynda, Jiří; Řezáčová, Pavlína; Horn, Martin; Mareš, Michael

    2015-01-01

    Roč. 22, č. 1 (2015), s. 43-44 ISSN 1211-5894. [Discussions in Structural Molecular Biology. Annual Meeting of the Czech Society for Structural Biology /13./. 19.03.2015-21.03.2015, Nové Hrady] Institutional support: RVO:61388963 ; RVO:68378050 Keywords : blood-feeding ticks * protein structure * proteolytic system Subject RIV: CE - Biochemistry

  15. Effects of feeding on arterial blood gases in the American alligator Alligator mississippiensis.

    Science.gov (United States)

    Busk, M; Overgaard, J; Hicks, J W; Bennett, A F; Wang, T

    2000-10-01

    Reptiles habitually ingest large meals at infrequent intervals, leading to changes in acid-base status as the net secretion of acid to the stomach causes a metabolic alkalosis (the alkaline tide). In chronically cannulated and undisturbed amphibians and reptiles, the pH changes in arterial blood are, nevertheless, reduced by a concomitant respiratory acidosis (increased P(CO2) caused by a relative hypoventilation). Alligators (Alligator mississippiensis) have been reported to exhibit exceptionally large increases in plasma [HCO3(-)] following feeding, but these studies were based on blood samples obtained by cardiac puncture, so stress and disturbance may have affected the blood gas levels. Furthermore, crocodilian haemoglobin is characterised by a unique binding of HCO3(-) that act to reduce blood oxygen-affinity, and it has been proposed that this feature safeguards oxygen offloading by counteracting pH effects on blood oxygen-affinity. Therefore, to study acid-base regulation and the interaction between the alkaline tide and oxygen transport in more detail, we describe the arterial blood gas composition of chronically cannulated and undisturbed alligators before and after voluntary feeding (meal size 7.5+/-1% of body mass). Digestion was associated with an approximately fourfold increase in metabolic rate (from 0.63+/-0.04 to 2.32+/-0.24 ml O(2) min(-1)kg(-1)) and was accompanied by a small increase in the respiratory gas exchange ratio. The arterial P(O2) of fasting alligators was 60.3+/-6.8 mmHg (1 mmHg = 0.133 kPa) and reached a maximum of 81.3+/-2.7 mmHg at 96 h following feeding; there was only a small increase in lactate levels, so the increased metabolic rate seems to be entirely aerobic. Plasma [HCO3(-)] increased from 24.4+/-1.1 to 36.9+/-1.7 mmol l(-1) (at 24 h), but since arterial P(CO2) increased from 29.0+/-1.1 to 36.8+/-1.3 mmHg, arterial pH remained virtually unaffected (changing from 7.51+/-0.01 to 7.58+/-0.01 at 24 h). The changes in plasma [HCO

  16. Natural blood feeding and temperature shift modulate the global transcriptional profile of Rickettsia rickettsii infecting its tick vector.

    Directory of Open Access Journals (Sweden)

    Maria Fernanda B M Galletti

    Full Text Available Rickettsia rickettsii is an obligate intracellular tick-borne bacterium that causes Rocky Mountain Spotted Fever (RMSF, the most lethal spotted fever rickettsiosis. When an infected starving tick begins blood feeding from a vertebrate host, R. rickettsii is exposed to a temperature elevation and to components in the blood meal. These two environmental stimuli have been previously associated with the reactivation of rickettsial virulence in ticks, but the factors responsible for this phenotype conversion have not been completely elucidated. Using customized oligonucleotide microarrays and high-throughput microfluidic qRT-PCR, we analyzed the effects of a 10°C temperature elevation and of a blood meal on the transcriptional profile of R. rickettsii infecting the tick Amblyomma aureolatum. This is the first study of the transcriptome of a bacterium in the genus Rickettsia infecting a natural tick vector. Although both stimuli significantly increased bacterial load, blood feeding had a greater effect, modulating five-fold more genes than the temperature upshift. Certain components of the Type IV Secretion System (T4SS were up-regulated by blood feeding. This suggests that this important bacterial transport system may be utilized to secrete effectors during the tick vector's blood meal. Blood feeding also up-regulated the expression of antioxidant enzymes, which might correspond to an attempt by R. rickettsii to protect itself against the deleterious effects of free radicals produced by fed ticks. The modulated genes identified in this study, including those encoding hypothetical proteins, require further functional analysis and may have potential as future targets for vaccine development.

  17. Water retention of repellent and subcritical repellent soils: New insights from model and experimental investigations

    Science.gov (United States)

    Czachor, H.; Doerr, S. H.; Lichner, L.

    2010-01-01

    SummarySoil organic matter can modify the surface properties of the soil mineral phase by changing the surface tension of the mineral surfaces. This modifies the soil's solid-water contact angle, which in turn would be expected to affect its water retention curve (SWRC). Here we model the impact of differences in the soil pore-water contact angle on capillarity in non-cylindrical pores by accounting for their complex pore geometry. Key outcomes from the model include that (i) available methods for measuring the Young's wetting angle on soil samples are insufficient in representing the wetting angle in the soil pore space, (ii) the wetting branch of water retention curves is strongly affected by the soil pore-water contact angle, as manifest in the wetting behavior of water repellent soils, (iii) effects for the drying branch are minimal, indicating that both wettable and water repellent soils should behave similarly, and (vi) water retention is a feature not of only wettable soils, but also soils that are in a water repellent state. These results are tested experimentally by determining drying and wetting branches for (a) 'model soil' (quartz sands with four hydrophobization levels) and (b) five field soil samples with contrasting wettability, which were used with and without the removal of the soil organic matter. The experimental results support the theoretical predictions and indicate that small changes in wetting angle can cause switches between wettable and water repellent soil behavior. This may explain the common observation that relatively small changes in soil water content can cause substantial changes in soil wettability.

  18. 1-Octen-3-ol – the attractant that repels [v1; ref status: indexed, http://f1000r.es/5ic

    Directory of Open Access Journals (Sweden)

    Pingxi Xu

    2015-06-01

    Full Text Available Since the discovery in the early 1980s that 1-octen-3-ol, isolated from oxen breath, attracts tsetse fly, there has been growing interest in exploring the use of this semiochemical as a possible generic lure for trapping host-seeking mosquitoes. Intriguingly, traps baited with 1-octen-3-ol captured significantly more females of the malaria mosquito, Anopheles gambiae, and the yellow fever mosquito, Aedes aegypti, than control traps, but failed to attract the southern house mosquito, Culex quinquefasciatus. Additionally, it has been demonstrated that this attractant is detected with enantioselective odorant receptors (ORs expressed only in maxillary palps. On the basis of indoor behavioral assays it has even been suggested that 1-octen-3-ol might be a repellent to the southern house mosquito. Our approach was two-prong, i.e., to isolate 1-octen-3-ol-sensitive ORs expressed in maxillary palps and antennae of southern house female mosquito, and test the hypothesis that this semiochemical is a repellent. An OR with high transcript levels in maxillary palps, CquiOR118b, showed remarkable selectivity towards (R-1-octen-3-ol, whereas an OR expressed in antennae, CquiOR114b, showed higher preference for (S-1-octen-3-ol than its antipode. Repellency by a surface landing and feeding assay showed that not only racemic, but enantiopure (R- and (S-1-octen-3-ol are repellents at 1% dose thus suggesting the occurrence of other (S-1-octen-3-ol-sensitive OR(s. Female mosquitoes with ablated maxillary palps were repelled by 1-octen-3-ol, which implies that in addition to OR(s in the maxillary palps, antennal OR(s are essential for repellency activity.

  19. Susceptibility of adult female Aedes aegypti (Diptera: Culicidae to the entomopathogenic fungus Metarhizium anisopliae is modified following blood feeding

    Directory of Open Access Journals (Sweden)

    Samuels Richard I

    2011-05-01

    Full Text Available Abstract Background The mosquito Aedes aegypti, vector of dengue fever, is a target for control by entomopathogenic fungi. Recent studies by our group have shown the susceptibility of adult A. aegypti to fungal infection by Metarhizium anisopliae. This fungus is currently being tested under field conditions. However, it is unknown whether blood-fed A. aegypti females are equally susceptible to infection by entomopathogenic fungi as sucrose fed females. Insect populations will be composed of females in a range of nutritional states. The fungus should be equally efficient at reducing survival of insects that rest on fungus impregnated surfaces following a blood meal as those coming into contact with fungi before host feeding. This could be an important factor when considering the behavior of A. aegypti females that can blood feed on multiple hosts over a short time period. Methods Female A. aegypti of the Rockefeller strain and a wild strain were infected with two isolates of the entomopathogenic fungus M. anisopliae (LPP 133 and ESALQ 818 using an indirect contact bioassay at different times following blood feeding. Survival rates were monitored on a daily basis and one-way analysis of variance combined with Duncan's post-hoc test or Log-rank survival curve analysis were used for statistical comparisons of susceptibility to infection. Results Blood feeding rapidly reduced susceptibility to infection, determined by the difference in survival rates and survival curves, when females were exposed to either of the two M. anisopliae isolates. Following a time lag which probably coincided with digestion of the blood meal (96-120 h post-feeding, host susceptibility to infection returned to pre-blood fed (sucrose fed levels. Conclusions Reduced susceptibility of A. aegypti to fungi following a blood meal is of concern. Furthermore, engorged females seeking out intra-domicile resting places post-blood feeding, would be predicted to rest for prolonged

  20. Susceptibility of adult female Aedes aegypti (Diptera: Culicidae) to the entomopathogenic fungus Metarhizium anisopliae is modified following blood feeding.

    Science.gov (United States)

    Paula, Adriano R; Carolino, Aline T; Silva, Carlos P; Samuels, Richard I

    2011-05-26

    The mosquito Aedes aegypti, vector of dengue fever, is a target for control by entomopathogenic fungi. Recent studies by our group have shown the susceptibility of adult A. aegypti to fungal infection by Metarhizium anisopliae. This fungus is currently being tested under field conditions. However, it is unknown whether blood-fed A. aegypti females are equally susceptible to infection by entomopathogenic fungi as sucrose fed females. Insect populations will be composed of females in a range of nutritional states. The fungus should be equally efficient at reducing survival of insects that rest on fungus impregnated surfaces following a blood meal as those coming into contact with fungi before host feeding. This could be an important factor when considering the behavior of A. aegypti females that can blood feed on multiple hosts over a short time period. Female A. aegypti of the Rockefeller strain and a wild strain were infected with two isolates of the entomopathogenic fungus M. anisopliae (LPP 133 and ESALQ 818) using an indirect contact bioassay at different times following blood feeding. Survival rates were monitored on a daily basis and one-way analysis of variance combined with Duncan's post-hoc test or Log-rank survival curve analysis were used for statistical comparisons of susceptibility to infection. Blood feeding rapidly reduced susceptibility to infection, determined by the difference in survival rates and survival curves, when females were exposed to either of the two M. anisopliae isolates. Following a time lag which probably coincided with digestion of the blood meal (96-120 h post-feeding), host susceptibility to infection returned to pre-blood fed (sucrose fed) levels. Reduced susceptibility of A. aegypti to fungi following a blood meal is of concern. Furthermore, engorged females seeking out intra-domicile resting places post-blood feeding, would be predicted to rest for prolonged periods on fungus impregnated black cloths, thus optimizing infection

  1. Toxicity, Tunneling and Feeding Behavior of the Termite, Coptotermes vastator, in Sand Treated with Oil of the Physic Nut, Jatropha curcas

    Science.gov (United States)

    Acda, Menandro N.

    2009-01-01

    Oil of the physic nut, Jatropha curcas L. (Malpighiales: Euphorbiaceae), was evaluated in the laboratory for its barrier and repellent activity against the Philippine milk termite Coptotermes vastator Light (Isoptera: Rhinotermitidae). The study showed that J. curcas oil had anti-feeding effect, induced reduction in tunneling activity and increased mortality in C. vastator. Behavior of termites exposed to sand treated with J. curcas oil indicated that it is toxic or repellent to C. vastator. Toxicity and repellent thresholds, were higher than those reported for other naturally occurring compounds tested against the Formosan subterranean termite. PMID:20053119

  2. Extract of the seeds of the plant Vitex agnus castus proven to be highly efficacious as a repellent against ticks, fleas, mosquitoes and biting flies.

    Science.gov (United States)

    Mehlhorn, Heinz; Schmahl, Günter; Schmidt, Jürgen

    2005-03-01

    About 70 plant extracts were tested for their ability to repel the attacks of blood-sucking arthropods. It was found that a CO2 extract of the seeds of the Mediterranean plant Vitex agnus castus (monk's pepper) can be used as a spray to keep away especially Ixodes ricinus and Rhipicephalus sanguineus ticks from animals and humans for at least 6 h. In addition mosquitoes, biting flies and fleas are also repelled for about 6 h.

  3. The effect of multiple blood-feeding on the longevity and insecticide resistant phenotype in the major malaria vector Anopheles arabiensis (Diptera: Culicidae).

    Science.gov (United States)

    Oliver, Shüné V; Brooke, Basil D

    2014-08-23

    Anopheles arabiensis is a major malaria vector in Africa. Adult females are likely to imbibe multiple blood meals during their lifetime. This results in regular exposure to potential toxins and blood-meal induced oxidative stress. Defence responses to these stressors may affect other factors of epidemiological significance, such as insecticide resistance and longevity. The aims of this study were to examine the effect of multiple blood-feeding on insecticide tolerance/resistance with increasing age, to assess the underlying biochemical mechanisms for the responses recorded, and to assess the effect of multiple blood-feeding on the life histories of adult females drawn from insecticide resistant and susceptible laboratory reared An. arabiensis. Laboratory reared An. arabiensis females from an insecticide resistant and an insecticide susceptible colony were offered either a single blood meal or multiple blood meals at 3-day intervals. Their tolerance or resistance to insecticide was then monitored by WHO bioassay four hours post blood-feeding. The biochemical basis of the phenotypic response was assessed by examining the effect of blood on detoxification enzyme activity and the effect of blood-meals on detoxification enzyme activity in ageing mosquitoes. Control cohorts that were not offered any blood meals showed steadily decreasing levels of insecticide tolerance/resistance with age, whereas a single blood meal significantly increased tolerance/resistance primarily at the age of three days. The expression of resistance/tolerance in those cohorts fed multiple blood meals generally showed the least variation with age. These results were consistent following exposure to DDT and pyrethroids but not to malathion. Multiple blood-meals also maintained the DDT and permethrin resistant phenotype, even after treatment females had stopped taking blood-meals. Biochemical analysis suggests that this phenotypic effect in resistant females may be mediated by the maintenance of

  4. Nootkatone is a repellent for Formosan subterranean termite (Coptotermes formosanus).

    Science.gov (United States)

    Zhu, B C; Henderson, G; Chen, F; Maistrello, L; Laine, R A

    2001-03-01

    We examined the behavior of Formosan subterranean termites toward one of the components of vetiver grass oil, the roots of which manufacture insect repellents. We found nootkatone, a sesquiterpene ketone, isolated from vetiver oil is a strong repellent and toxicant to Formosan subterranean termites. The lowest effective concentration tested was 10 micrograms/g substrate. This is the first report of nootkatone being a repellent to insects.

  5. Natural and fire-induced soil water repellency in a Portugese Shrubland

    NARCIS (Netherlands)

    Stoof, C.R.; Moore, D.; Ritsema, C.J.; Dekker, L.W.

    2011-01-01

    Post-fire land degradation is often attributed to fire-induced soil water repellency, despite the fact that soil water repellency is a natural phenomenon in many soils and is therefore not necessarily caused by fire. To improve our understanding of the role of soil water repellency in causing

  6. Seasonal blood-feeding behavior of Culex tarsalis (Diptera: Culicidae) in Weld County, Colorado, 2007.

    Science.gov (United States)

    Kent, Rebekah; Juliusson, Lara; Weissmann, Michael; Evans, Sara; Komar, Nicholas

    2009-03-01

    Studies on Culex tarsalis Coquillett in Colorado have shown marked seasonal variation in the proportion of blood meals from birds and mammals. However, limitations in the specificity of antibodies used in the precipitin test and lack of vertebrate host availability data warrant revisiting Cx. tarsalis blood feeding behavior in the context of West Nile virus (WNV) transmission. We characterized the host preference of Cx. tarsalis during peak WNV transmission season in eastern Colorado and estimated the relative contribution of different avian species to WNV transmission. Cx. tarsalis preferred birds to mammals each month, although the proportion of blood meals from mammals increased in July and August. The distribution of blood meals differed significantly across months, in part because of changes in the proportion of blood meals from American robins, a preferred host. The estimated proportion of WNV-infectious vectors derived from American robins declined from 60 to 1% between June and August. The majority of avian blood meals came from doves, preferred hosts that contributed 25-40% of the WNV-infectious mosquitoes each month. Active WNV transmission was observed in association with a large house sparrow communal roost. These data show how seasonal patterns in Cx. tarsalis blood feeding behavior relate to WNV transmission in eastern Colorado, with the American robin contributing greatly to early-season virus transmission and a communal roost of sparrows serving as a focus for late-season amplification.

  7. Attracting and repelling in homogeneous signal processes

    International Nuclear Information System (INIS)

    Downarowicz, T; Grzegorek, P; Lacroix, Y

    2010-01-01

    Attracting and repelling are discussed on two levels: in abstract signal processes and in signal processes arising as returns to a fixed set in an ergodic dynamical system. In the first approach, among other things, we give three examples in which the sum of two Poisson (hence neutral—neither attracting nor repelling) processes comes out either neutral or attracting, or repelling, depending on how the two processes depend on each other. The main new result of the second type concerns so-called 'composite events' in the form of a union of all cylinders over blocks belonging to the δ-ball in the Hamming distance around a fixed block. We prove that in a typical ergodic nonperiodic process the majority of such 'composite events' reveal strong attracting. We discuss the practical interpretation of this result

  8. Ceramic coatings for water-repellent textiles

    Science.gov (United States)

    Colleoni, C.; Esposito, F.; Guido, E.; Migani, V.; Trovato, V.; Rosace, G.

    2017-10-01

    In recent years, ceramic coatings have been widely studied for their potential performance in many scientific and technological fields. Ceramic coatings are also used as a textile-finishing agent to impart several properties such as anti-bacterial, anti-abrasion, flame retardant. In this study, fluoro free water repellent finishings have been developed to assess the features of the silica films on the textile fabrics. The water repellency of the treated samples has been evaluated by different tests such as water contact angle, water uptake and drop test.

  9. The efficacy of repellents against Aedes, Anopheles, Culex and Ixodes spp. - a literature review.

    Science.gov (United States)

    Lupi, Eleonora; Hatz, Christoph; Schlagenhauf, Patricia

    2013-01-01

    Travellers are confronted with a variety of vector-borne threats. Is one type of repellent effective against all biting vectors? The aim of this review is to examine the literature, up to December 31st, 2012, regarding repellent efficacy. We searched PubMed for relevant papers. Repellents of interest were DEET, Icaridin as well as other piperidine-derived products (SS220), Insect Repellent (IR) 3535 (ethyl-butylacetyl-amino-propionat, EBAAP) and plant-derived products, including Citriodora (para-menthane-3,8-diol). As vectors, we considered the mosquito species Anopheles, Aedes and Culex as well as the tick species Ixodes. We selected only studies evaluating the protective efficacy of repellents on human skin. We reviewed a total of 102 publications. Repellents were evaluated regarding complete protection time or as percentage efficacy [%] in a time interval. We found no standardized study for tick bite prevention. Regarding Aedes, DEET at concentration of 20% or more, showed the best efficacy providing up to 10 h protection. Citriodora repellency against this mosquito genus was lower compared to the other products. Also between subspecies a difference could be observed: Ae. aegypti proved more difficult to repel than Ae. Albopictus. Fewer studies have been conducted on mosquito species Anopheles and Culex. The repellency profile against Anopheles species was similar for the four principal repellents of interest, providing on average 4-10 h of protection. Culex mosquitoes are easier to repel and all four repellents provided good protection. Few studies have been conducted on the tick species Ixodes. According to our results, the longest protection against Ixodes scapularis was provided by repellents containing IR3535, while DEET and commercial products containing Icaridin or PMD showed a better response than IR3535 against Ixodes ricinus. Many plant-based repellents provide only short duration protection. Adding vanillin 5% to plant-based repellents and to DEET

  10. Super liquid-repellent gas membranes for carbon dioxide capture and heart-lung machines.

    Science.gov (United States)

    Paven, Maxime; Papadopoulos, Periklis; Schöttler, Susanne; Deng, Xu; Mailänder, Volker; Vollmer, Doris; Butt, Hans-Jürgen

    2013-01-01

    In a gas membrane, gas is transferred between a liquid and a gas through a microporous membrane. The main challenge is to achieve a high gas transfer while preventing wetting and clogging. With respect to the oxygenation of blood, haemocompatibility is also required. Here we coat macroporous meshes with a superamphiphobic-or liquid repellent-layer to meet this challenge. The superamphiphobic layer consists of a fractal-like network of fluorinated silicon oxide nanospheres; gas trapped between the nanospheres keeps the liquid from contacting the wall of the membrane. We demonstrate the capabilities of the membrane by capturing carbon dioxide gas into a basic aqueous solution and in addition use it to oxygenate blood. Usually, blood tends to clog membranes because of the abundance of blood cells, platelets, proteins and lipids. We show that human blood stored in a superamphiphobic well for 24 h can be poured off without leaving cells or adsorbed protein behind.

  11. Multiple blood feeding and host-seeking behavior in Aedes aegypti and Aedes albopictus (Diptera: Culicidae).

    Science.gov (United States)

    Farjana, Thahsin; Tuno, Nobuko

    2013-07-01

    The body size of mosquitoes can influence a number of bionomic factors, such as their blood-feeding ability, host attack rate, and fecundity. All of these traits are important determinants of their potential to transmit diseases. Among abiotic and biotic factors, high temperature and low nutrition in the developing stages of mosquitoes generally result in small adults. We studied the relationship between body size and multiple feeding in a gonotrophic cycle and some fecundity attributes by using three strains of two competent vector species, Aedes aegypti (L.) and Aedes albopictus (Skuse). We raised small and large mosquitoes under low and high food conditions in the laboratory to measure parameters of fecundity and blood-feeding behavior. Fecundity was positively correlated with body size in both species, whereas the number of bloodmeals, the frequency of host-seeking behavior, and egg retention were negatively correlated with body size in the Ae. albopictus Nagasaki strain. We found that multiple feeding and host-seeking behavior were negatively correlated with body size, i.e., small mosquitoes tended to have more contact with hosts. We found that two mechanisms that inhibit engorged mosquitoes from seeking out hosts, distension-induced and oocyte-induced inhibition, were not strong enough to limit host-seeking behavior, and multiple feeding increased fecundity. Size-dependent multiple feeding and host-seeking behavior affect contact frequency with hosts and should be considered when predicting how changes in mosquito body size affect disease transmission.

  12. Polymer-based Drug Delivery Systems Applied to Insects Repellents Devices: A Review.

    Science.gov (United States)

    Barradas, Thaís Nogueira; Senna, Juliana Perdiz; Ricci, Eduardo; Mansur, Claudia Regina Elias

    2016-01-01

    Insects-borne diseases constitute a public health concern. Since there is no vaccine or curative treatment for many of these diseases, individual protection is the main approach to prevent them. Nowadays, the search for replacing synthetic molecules for insect repellents from natural sources, such as essential oils, is increasing. However, most of them present low efficiency compared to synthetic repellents. Therefore, decreasing skin permeation of synthetic repellents or yet, increasing effectiveness of natural repellents are challenges that must be overcome during the development of novel insect repellent formulations. In this context, polymer-based formulations allow entrapping active ingredients and provide release control. Encapsulation into polymeric micro/nanocapsules, cyclodextrins, polymeric micelles or hydrogels constitutes an approach to modify physicochemical properties of encapsulated molecules. Such techniques, applied in topical formulations, fabrics modification for personal protection, or food packaging have proved to be more effective in increasing repellency time and also in reducing drug dermal absorption, improving safety profiles of these products. In this work, the main synthetic and natural insect repellents are described as well as their polymeric carrier systems and their potential applications.

  13. Bioassay-Guided Investigation of Two Monarda Essential Oils as Repellents of Yellow Fever Mosquito Aedes aegypti

    Science.gov (United States)

    2013-08-06

    suppressed the postprandial elevation of blood triacylglycerol concentrations in mice in vivo; however, five other monoterpene glycosides that were isolated...components, leading to the isolation of compounds with mosquito repellent activity, but without any cytotoxicity. The monoterpene hydrocarbon p-cymene...Kobayashi, K.; Miyase, T.; Yoshizaki, F. A lipase inhibitor monoterpene and monoterpene glycosides from Monarda punctata. Phytochemistry 2010, 71, 1884

  14. Do insect repellents induce drift behaviour in aquatic non-target organisms?

    Science.gov (United States)

    Fink, Patrick; Moelzner, Jana; Berghahn, Ruediger; von Elert, Eric

    2017-01-01

    Synthetic insect repellents are compounds applied to surfaces to discourage insects, mainly mosquitoes, from landing on those surfaces. As some of these repellents have repeatedly been detected in surface waters at significant concentrations, they may also exert repellent effects on aquatic non-target organisms. In running water systems, aquatic invertebrates actively enter downstream drift in order to avoid unfavourable environmental conditions. We thus tested the hypothesis that the widely used insect repellents DEET (N,N-Diethyl-m-toluamide), EBAAP (3-[N-butyl-N-acetyl]-aminopropionic acid ethyl ester) and Icaridin (1-piperidinecarboxylic acid 2-(2-hydroxyethyl)-1-methylpropyl ester) induce downstream drift behaviour in the aquatic invertebrates Gammarus pulex (Crustacea, Amphipoda) and Cloeon dipterum (Insecta, Ephemeroptera), using a laboratory-scale drift assay. We found no clear increase in the drift behaviour of both invertebrate species across a concentration gradient of eight orders of magnitude and even beyond maximum environmental concentrations for any of the three repellents. We found no evidence for a direct drift-inducing activity of insect repellents on aquatic non-target organisms. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Effectiveness of Gel Repellents on Feral Pigeons

    Directory of Open Access Journals (Sweden)

    Birte Stock

    2013-12-01

    Full Text Available Millions of feral pigeons (Columba livia live in close association with the human population in our cities. They pose serious health risks to humans and lead to high economic loss due to damage caused to buildings. Consequently, house owners and city authorities are not willing to allow pigeons on their buildings. While various avian repellents are regularly introduced onto the market, scientific proof of efficacy is lacking. This study aimed at testing the effectiveness of two avian gel repellents and additionally examined their application from animal welfare standpoint. The gels used an alleged tactile or visual aversion of the birds, reinforced by additional sensory cues. We mounted experimental shelves with the installed repellents in a pigeon loft and observed the behavior of free-living feral pigeons towards the systems. Both gels showed a restricted, transient repellent effect, but failed to prove the claimed complete effectiveness. Additionally, the gels’ adhesive effect remains doubtful in view of animal welfare because gluing of plumage presents a risk to feral pigeons and also to other non-target birds. This study infers that both gels lack the promised complete efficacy, conflict with animal welfare concerns and are therefore not suitable for feral pigeon management in urban areas.

  16. Repellency of Plant Extracts against the Legume Flower Thrips Megalurothrips sjostedti (Thysanoptera: Thripidae

    Directory of Open Access Journals (Sweden)

    Andnet Abtew

    2015-06-01

    Full Text Available Megalurothrips sjostedti Trybom is an important pest of cowpea (Vigna unguiculata L. in Africa. To propose an alternative to chemical control, the repellency of 24 plant extracts was evaluated against adult female thrips of M. sjostedti in the laboratory. Plant extracts in ethanol were separately applied on a filter paper disk in a still air visual cue olfactometer. The results showed highly significant differences in repellency among extract type, concentration and their interactions. We classified the level of repellency into four categories as strong, good, moderate and weak or non- repellent based on hierarchical ascendant classification. We identified Piper nigrum, Cinnamomum zeylanicum, Cinnamomum cassia as strong repellents. Five extracts were classified as good, eight as moderate and the remaining eight extracts were weak or non-repellent. Repellency of the extracts increased with the concentration suggesting that the behavioral response of M. sjostedti was dose-dependent. Mono- and sesquiterpene hydrocarbon compounds from seven highly repellent extracts were identified by gas chromatography-mass spectrometry (GC/MS. The use of repellent extracts could be useful in developing integrated pest management strategies for thrips on legume crops. In this regard, the specific modes of action of the identified compounds need to be investigated to incorporate them into the existing crop protection strategies.

  17. Chemical and Plant-Based Insect Repellents: Efficacy, Safety, and Toxicity.

    Science.gov (United States)

    Diaz, James H

    2016-03-01

    Most emerging infectious diseases today are arthropod-borne and cannot be prevented by vaccinations. Because insect repellents offer important topical barriers of personal protection from arthropod-borne infectious diseases, the main objectives of this article were to describe the growing threats to public health from emerging arthropod-borne infectious diseases, to define the differences between insect repellents and insecticides, and to compare the efficacies and toxicities of chemical and plant-derived insect repellents. Internet search engines were queried with key words to identify scientific articles on the efficacy, safety, and toxicity of chemical and plant-derived topical insect repellants and insecticides to meet these objectives. Data sources reviewed included case reports; case series; observational, longitudinal, and surveillance studies; and entomological and toxicological studies. Descriptive analysis of the data sources identified the most effective application of insect repellents as a combination of topical chemical repellents, either N-diethyl-3-methylbenzamide (formerly N, N-diethyl-m-toluamide, or DEET) or picaridin, and permethrin-impregnated or other pyrethroid-impregnated clothing over topically treated skin. The insecticide-treated clothing would provide contact-level insecticidal effects and provide better, longer lasting protection against malaria-transmitting mosquitoes and ticks than topical DEET or picaridin alone. In special cases, where environmental exposures to disease-transmitting ticks, biting midges, sandflies, or blackflies are anticipated, topical insect repellents containing IR3535, picaridin, or oil of lemon eucalyptus (p-menthane-3, 8-diol or PMD) would offer better topical protection than topical DEET alone. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  18. Repellent Activity of TRIG (N-N Diethyl Benzamide) against Man-Biting Mosquitoes

    OpenAIRE

    Msangi, Shandala; Kweka, Eliningaya; Mahande, Aneth

    2018-01-01

    A study was conducted to assess efficacy of a new repellent brand TRIG (15% N-N Diethyl Benzamide) when compared to DEET (20% N-N Methyl Toluamide). The repellents were tested in laboratory and field. In the laboratory, the repellence was tested on human volunteers, by exposing their repellent-treated arms on starved mosquitoes in cages for 3 minutes at hourly intervals, while counting the landing and probing attempts. Anopheles gambiae and Aedes aegypti mosquitoes were used. Field evaluation...

  19. Substitution of PFAS chemistry in outdoor apparel and the impact on repellency performance.

    Science.gov (United States)

    Hill, Philippa J; Taylor, Mark; Goswami, Parikshit; Blackburn, Richard S

    2017-08-01

    Intensifying legislation and increased research on the toxicological and persistent nature of per- and polyfluoroalkyl substances (PFASs) have recently influenced the direction of liquid repellent chemistry use; environmental, social, and sustainability responsibilities are at the crux. Without PFAS chemistry, it is challenging to meet current textile industry liquid repellency requirements, which is a highly desirable property, particularly in outdoor apparel where the technology helps to provide the wearer with essential protection from adverse environmental conditions. Herein, complexities between required functionality, legislation and sustainability within outdoor apparel are discussed, and fundamental technical performance of commercially available long-chain (C8) PFASs, shorter-chain (C6) PFASs, and non-fluorinated repellent chemistries finishes are evaluated comparatively. Non-fluorinated finishes provided no oil repellency, and were clearly inferior in this property to PFAS-finished fabrics that demonstrated good oil-resistance. However, water repellency ratings were similar across the range of all finished fabrics tested, all demonstrating a high level of resistance to wetting, and several non-fluorinated repellent fabrics provide similar water repellency to long-chain (C8) PFAS or shorter-chain (C6) PFAS finished fabrics. The primary repellency function required in outdoor apparel is water repellency, and we would propose that the use of PFAS chemistry for such garments is over-engineering, providing oil repellency that is in excess of user requirements. Accordingly, significant environmental and toxicological benefits could be achieved by switching outdoor apparel to non-fluorinated finishes without a significant reduction in garment water-repellency performance. These conclusions are being supported by further research into the effect of laundering, abrasion and ageing of these fabrics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Growth, Feed Utilization and Blood Metabolic Responses to Different Amylose-amylopectin Ratio Fed Diets in Tilapia (

    Directory of Open Access Journals (Sweden)

    Meng-Yao Chen

    2013-08-01

    Full Text Available A feeding trial was conducted in tilapia to determine the growth performance, nutrient digestibility, digestive enzymes, and postprandial blood metabolites in response to different dietary amylose-amylopectin ratios. Five isonitrogenous and isolipidic diets containing an equal starch level with different amylose-amylopectin ratios of 0.11 (diet 1, 0.24 (diet 2, 0.47 (diet 3, 0.76 (diet 4 and 0.98 (diet 5 were formulated using high-amylose corn starch (as the amylose source and waxy rice (as the amylopectin source. Each diet was hand-fed to six tanks of 15 fish each, three times a day over a 6-wk period. After the growth trial, a postprandial blood metabolic test was carried out. Fish fed diet 2 exhibited the highest percent weight gain and feed efficiency and protein efficiency ratio, whereas fish fed with diet 5 showed the lowest growth and feed utilization among treatments. The digestibility for starch in fish fed diet 1 and 2 was higher than those in fish fed with other diets (p<0.05. The highest activities for protease, lipase and amylase were found in fish fed the diet 2, diet 1, and diet 1 respectively among dietary treatments, while the lowest values for these indexes were observed in fish fed the diet 3, diet 5 and diet 4, respectively. The liver glycogen concentrations in fish fed diets 4 and 5 were found higher than in fish fed other diets (p<0.05. The feeding rate, hepatosomatic index, condition factor, and plasma parmeters (glucose, triglyceride, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol did not differ across treatments. In terms of postprandial blood responses, peak blood glucose and triglycerides were lower after 3 or 6 h in the fish fed with diets 3–5 than in the fish fed diet 1, but delayed peak blood total amino acid time was observed in fish fed with the diets 1 or 2. The lowest peak values for each of the three blood metabolites were observed in fish fed diet 5. The

  1. Preferential flow in water-repellent sandy soils : model development and lysimeter experiments

    NARCIS (Netherlands)

    Rooij, de G.H.

    1996-01-01


    When water enters a water-repellent topsoil, preferential flow paths develop and the flow bypasses a large part of the unsaturated zone. Therefore, preferential flow caused by water- repellency is expected to accelerate solute leaching to the groundwater. In soils with water-repellent

  2. Essential oils and their compositions as spatial repellents for pestiferous social wasps.

    Science.gov (United States)

    Zhang, Qing-He; Schneidmiller, Rodney G; Hoover, Doreen R

    2013-04-01

    The study objectives were: (1) to field test potential repellency of common essential oils against several pestiferous social wasps (Hymenoptera: Vespidae), using attractant-baited traps; (2) to identify vespid antennally active compounds from the repellent essential oils; (3) to determine potential repellency of these electroantennographic detection (EAD) active compounds in the field. Of the 21 essential oils tested, 17 showed significant repellency on yellowjackets [mainly Vespula pensylvanica (Saussure)] and paper wasps [mainly Polistes dominulus (Christ)]: clove, pennyroyal, lemongrass, ylang ylang, spearmint, wintergreen, sage, rosemary, lavender, geranium, patchouli, citronella, Roman chamomile, thyme, fennel seed, anise and peppermint. Two essential oil mixtures - 3EO-mix (clove, geranium and lemongrass) and 4EO-mix (clove, geranium, lemongrass and rosemary) - totally blocked the attraction of vespid workers. Twenty-nine vespid antennally active compounds were identified from solid-phase microextraction (SPME) samples of 11 strongly repellent essential oils by GC-EAD/MS techniques. Among the synthetic EAD-active compounds field tested, eugenol, P/I-menthone, pulegone, α/β-thujone, l-carvone, E/Z-citral, citronellal, methyl benzoate, benzyl acetate, methyl salicylate and 3-octanol showed a significant repellency on vespid workers. These compounds are likely responsible for the repellency of their corresponding essential oils. These repellent essential oils and their active compositions have great potential for efficient, environmentally sound semiochemical-based IPM of pestiferous vespid wasps. © 2012 Society of Chemical Industry.

  3. Direct methanol feed fuel cell with reduced catalyst loading

    Science.gov (United States)

    Kindler, Andrew (Inventor)

    1999-01-01

    Improvements to direct feed methanol fuel cells include new protocols for component formation. Catalyst-water repellent material is applied in formation of electrodes and sintered before application of ionomer. A membrane used in formation of an electrode assembly is specially pre-treated to improve bonding between catalyst and membrane. The improved electrode and the pre-treated membrane are assembled into a membrane electrode assembly.

  4. Mosquito repellent activity of essential oils of aromatic plants growing in Argentina.

    Science.gov (United States)

    Gillij, Y G; Gleiser, R M; Zygadlo, J A

    2008-05-01

    Mosquitoes are important vectors of diseases and nuisance pests. Repellents minimize contact with mosquitoes. Repellents based on essential oils (EO) are being developed as an alternative to DEET (N,N-diethyl-m-methylbenzamide), an effective compound that has disadvantages including toxic reactions, and damage to plastic and synthetic fabric. This work evaluated the repellency against Aedes aegypti of EO from aromatic plants that grow in Argentina: Acantholippia seriphioides, Achyrocline satureioides, Aloysia citriodora, Anemia tomentosa, Baccharis spartioides, Chenopodium ambrosioides, Eucalyptus saligna, Hyptis mutabilis, Minthostachys mollis, Rosmarinus officinalis, Tagetes minuta and Tagetes pusilla. Most EO were effective. Variations depending on geographic origin of the plant were detected. At a 90% EO concentration, A. satureoides and T. pusilla were the least repellent. At concentrations of 12.5% B. spartioides, R. officinalis and A. citriodora showed the longest repellency times. Comparisons of the principal components of each EO suggest that limonene and camphor were the main components responsible for the repellent effects.

  5. Identification of salivary gland proteins depleted after blood feeding in the malaria vector Anopheles campestris-like mosquitoes (Diptera: Culicidae.

    Directory of Open Access Journals (Sweden)

    Sriwatapron Sor-suwan

    Full Text Available Malaria sporozoites must invade the salivary glands of mosquitoes for maturation before transmission to vertebrate hosts. The duration of the sporogonic cycle within the mosquitoes ranges from 10 to 21 days depending on the parasite species and temperature. During blood feeding salivary gland proteins are injected into the vertebrate host, along with malaria sporozoites in the case of an infected mosquito. To identify salivary gland proteins depleted after blood feeding of female Anopheles campestris-like, a potential malaria vector of Plasmodium vivax in Thailand, two-dimensional gel electrophoresis and nano-liquid chromatography-mass spectrometry techniques were used. Results showed that 19 major proteins were significantly depleted in three to four day-old mosquitoes fed on a first blood meal. For the mosquitoes fed the second blood meal on day 14 after the first blood meal, 14 major proteins were significantly decreased in amount. The significantly depleted proteins in both groups included apyrase, 5'-nucleotidase/apyrase, D7, D7-related 1, short form D7r1, gSG6, anti-platelet protein, serine/threonine-protein kinase rio3, putative sil1, cyclophilin A, hypothetical protein Phum_PHUM512530, AGAP007618-PA, and two non-significant hit proteins. To our knowledge, this study presents for the first time the salivary gland proteins that are involved in the second blood feeding on the day corresponding to the transmission period of the sporozoites to new mammalian hosts. This information serves as a basis for future work concerning the possible role of these proteins in the parasite transmission and the physiological processes that occur during the blood feeding.

  6. Identification of salivary gland proteins depleted after blood feeding in the malaria vector Anopheles campestris-like mosquitoes (Diptera: Culicidae).

    Science.gov (United States)

    Sor-suwan, Sriwatapron; Jariyapan, Narissara; Roytrakul, Sittiruk; Paemanee, Atchara; Phumee, Atchara; Phattanawiboon, Benjarat; Intakhan, Nuchpicha; Chanmol, Wetpisit; Bates, Paul A; Saeung, Atiporn; Choochote, Wej

    2014-01-01

    Malaria sporozoites must invade the salivary glands of mosquitoes for maturation before transmission to vertebrate hosts. The duration of the sporogonic cycle within the mosquitoes ranges from 10 to 21 days depending on the parasite species and temperature. During blood feeding salivary gland proteins are injected into the vertebrate host, along with malaria sporozoites in the case of an infected mosquito. To identify salivary gland proteins depleted after blood feeding of female Anopheles campestris-like, a potential malaria vector of Plasmodium vivax in Thailand, two-dimensional gel electrophoresis and nano-liquid chromatography-mass spectrometry techniques were used. Results showed that 19 major proteins were significantly depleted in three to four day-old mosquitoes fed on a first blood meal. For the mosquitoes fed the second blood meal on day 14 after the first blood meal, 14 major proteins were significantly decreased in amount. The significantly depleted proteins in both groups included apyrase, 5'-nucleotidase/apyrase, D7, D7-related 1, short form D7r1, gSG6, anti-platelet protein, serine/threonine-protein kinase rio3, putative sil1, cyclophilin A, hypothetical protein Phum_PHUM512530, AGAP007618-PA, and two non-significant hit proteins. To our knowledge, this study presents for the first time the salivary gland proteins that are involved in the second blood feeding on the day corresponding to the transmission period of the sporozoites to new mammalian hosts. This information serves as a basis for future work concerning the possible role of these proteins in the parasite transmission and the physiological processes that occur during the blood feeding.

  7. Evaluation of Repellency Effect of Essential Oils of Satureja khuzestanica (Carvacrol, Myrtus communis (Myrtle, Lavendula officinalis and Salvia sclarea using Standard WHO Repellency Tests.

    Directory of Open Access Journals (Sweden)

    Mohammad Hassan Kayedi

    2014-06-01

    Full Text Available Using special lotions and repellent sprays on skin is one of the effective methods to prevent Arthropods biting which was verified in this study.Essential oils of four plants (Satureja khuzestanica, Salvia sclarea, Lavendula officinalis and Myrtus communis were separately extracted by Clevenger used hydro distillation method. Then separated solutions with 10%, 20% and 40% concentrations of essential oils of plants in 99.6 % ethanol were prepared. WHO guidelines for efficacy testing of mosquito repellents for human skin were used on different concentrations of essential oils of plants, traditional repellents (DEET, 50% and 33% as positive control, and ethanol 99.6% and naked hands as negative controls.In negative control groups, the number of bits were comparable (P= 0.42 and had decreasing time trends (naked hands P= 0.011, ethanol P< 0.001. In all time points, minimum bites were observed in traditional repellents and it was significantly less than the other groups (P< 0.001. The time trend in the number of bites in the other groups was positive and showed minimum number of bites in time zero in all groups. We also found that the concentration of repellents had association with the number of bites. The maximum and minimum numbers of bites were observed with 10% and 40% concentrations respectively in all groups.Essential oils of Salvia sclarea, Lavendula officinalis and Myrtus communis have repellency effect, even with 10% concentration of essential oils.

  8. A novel test cage with an air ventilation system as an alternative to conventional cages for the efficacy testing of mosquito repellents.

    Science.gov (United States)

    Obermayr, U; Rose, A; Geier, M

    2010-11-01

    We have developed a novel test cage and improved method for the evaluation of mosquito repellents. The method is compatible with the United States Environmental Protection Agency, 2000 draft OPPTS 810.3700 Product Performance Test Guidelines for Testing of Insect Repellents. The Biogents cages (BG-cages) require fewer test mosquitoes than conventional cages and are more comfortable for the human volunteers. The novel cage allows a section of treated forearm from a volunteer to be exposed to mosquito probing through a window. This design minimizes residual contamination of cage surfaces with repellent. In addition, an air ventilation system supplies conditioned air to the cages after each single test, to flush out and prevent any accumulation of test substances. During biting activity tests, the untreated skin surface does not receive bites because of a screen placed 150 mm above the skin. Compared with the OPPTS 810.3700 method, the BG-cage is smaller (27 liters, compared with 56 liters) and contains 30 rather than hundreds of blood-hungry female mosquitoes. We compared the performance of a proprietary repellent formulation containing 20% KBR3023 with four volunteers on Aedes aegypti (L.) (Diptera: Culicidae) in BG- and conventional cages. Repellent protection time was shorter in tests conducted with conventional cages. The average 95% protection time was 4.5 +/- 0.4 h in conventional cages and 7.5 +/- 0.6 h in the novel BG-cages. The protection times measured in BG-cages were more similar to the protection times determined with these repellents in field tests.

  9. Structure-activity of valencenoid derivatives and their repellence to the Formosan subterranean termite.

    Science.gov (United States)

    Zhu, Betty C R; Henderson, Gregg; Sauer, Anne M; Yu, Ying; Crowe, William; Laine, Roger A

    2003-12-01

    Eight valencenoid derivatives were evaluated for their repelling activity against Formosan subterranean termites, Coptotermes formosanus Shiraki. Among them, 1,10-dihydronootkatone was the strongest repellent, and valencene was the weakest. Results of the structure-repellency relationships indicated (1) reduction of the ketone group to the alcohol on position 2 of nootkatone curtailed the activity; (2) because of the low activity of valencene relative to nootkatone that the ketone group was essential for repellent activity; (3) reduction of the 1,10 double bond (1,10-dihydronootkatone and tetrahydronootkatone) produced compounds more repellent than nootkatone; (4) the isopropenyl group probably does not participate in binding as evidenced by no significant difference in the repellent activity among nootkatone (double bond between position 11 and 12), isonootkatone (double bond between position 7 and 11), and 11,12-dihydronootkatone.

  10. Efeitos de atrativos e repelentes sobre o comportamento da abelha (Apis mellifera, l. Effect of attractants and repellents on the behavior of honey bees (Apis mellipera, L.

    Directory of Open Access Journals (Sweden)

    D.T. MALERBO-SOUZA

    1998-01-01

    Full Text Available O objetivo do presente ensaio foi testar diversas substâncias e verificar sua atratividade e repelência para abelhas, Apis mellifera, L. Para isso, foram realizados testes em discos próximos às colméias e em cana picada oferecida como alimentação para gado bovino confinado. Nos discos próximos à colméia, o produto mais atrativo foi Bee-Here e o mais repelente foi o óleo de citronela. No cocho para bovinos, o repelente mais efetivo foi n-octyl-acetato.The experiment aimed to study honey bee (Apis mellifera attractants and repellents in vitro and on chopped sugar cane for bovine feeding. Tests were performed on plates located near to the hives and on bovine-hods. On plates, Bee-Here® was the most attractive and citronela oil the most repellent. On bovine-hods the most effective was n-octyl-acetate.

  11. Identification of Salivary Gland Proteins Depleted after Blood Feeding in the Malaria Vector Anopheles campestris-like Mosquitoes (Diptera: Culicidae)

    OpenAIRE

    Sor-suwan, Sriwatapron; Jariyapan, Narissara; Roytrakul, Sittiruk; Paemanee, Atchara; Phumee, Atchara; Phattanawiboon, Benjarat; Intakhan, Nuchpicha; Chanmol, Wetpisit; Bates, Paul A.; Saeung, Atiporn; Choochote, Wej

    2014-01-01

    Malaria sporozoites must invade the salivary glands of mosquitoes for maturation before transmission to vertebrate hosts. The duration of the sporogonic cycle within the mosquitoes ranges from 10 to 21 days depending on the parasite species and temperature. During blood feeding salivary gland proteins are injected into the vertebrate host, along with malaria sporozoites in the case of an infected mosquito. To identify salivary gland proteins depleted after blood feeding of female Anopheles ca...

  12. Preliminary Study of Water Repellent Properties of Red Pepper Seed Oil

    Science.gov (United States)

    Kurniawan, F.; Madurani, K. A.; Wahyulis, N. C.

    2017-03-01

    The water-repellent properties of red pepper seed oil (capsicol) have been studied. The oil was coated on the glass surface by spray technique. Water repellent properties were performed by measuring the contact angle of water droplets. The measurement was conducted by varying the drying time of the oil coating at room temperature. The optimum contact angle of the droplets on the glass with capsicol coating is 46.77°, which can be achieved in 30 min of drying time. It also obtained the smallest diameter of the droplets (0.47 cm). The longer drying time decrease the contact angles and increases the diameter. The results were compared with the bare glass and commercial water repellent. The contact angle of the droplets on the glass surface with capsicol coating is higher than bare glass, but lower than glass with commercial water repellent coating. It means that capsicol has the water-repellent properties.

  13. Host species diversity and post-blood feeding carbohydrate availability enhance survival of females and fecundity in Aedes albopictus (Diptera: Culicidae).

    Science.gov (United States)

    Xue, Rui-De; Ali, Arshad; Barnard, Donald R

    2008-06-01

    Aedes albopictus mosquito is an opportunistic blood feeder and has a broad host range. The feeding behavior and habits of this mosquito are liable to increase the transmission potential of arboviruses. The survival and fecundity in A. albopictus fed on different hosts and post-blood meal provision of sugar were investigated in a laboratory-reared colony. Adult survival of caged female A. albopictus that were fed on blood of two different hosts (double meal) was higher than the females fed only on one host (single meal) (mean survival: 70.2+/-9.6 vs. 55.5+/-5.5%, respectively) when held in the laboratory for 72 h after blood feeding. Mean survival of females provided 10% sucrose solution (in water) after a single or double blood meal was higher (90.5+/-6.4% and 89.3+/-6.5%, respectively) than in the respective groups receiving water only following blood feeding (double meal: 49.0+/-9.6%; single meal: 45.3+/-10.9%). Females receiving a double meal were more fecund on average (89.0+/-6.6 eggs) than females provided a single meal (82.3+/-8.2 eggs).

  14. Emerging roles of aquaporins in relation to the physiology of blood-feeding arthropods.

    Science.gov (United States)

    Benoit, Joshua B; Hansen, Immo A; Szuter, Elise M; Drake, Lisa L; Burnett, Denielle L; Attardo, Geoffrey M

    2014-10-01

    Aquaporins (AQPs) are proteins that span plasma membranes allowing the movement of water and small solutes into or out of cells. The type, expression levels and activity of AQPs play a major role in the relative permeability of each cell to water or other solutes. Research on arthropod AQPs has expanded in the last 10 years due to the completion of several arthropod genome projects and the increased availability of genetic information accessible through other resources such as de novo transcriptome assemblies. In particular, there has been significant advancement in elucidating the roles that AQPs serve in relation to the physiology of blood-feeding arthropods of medical importance. The focus of this review is upon the significance of AQPs in relation to hematophagy in arthropods. This will be accomplished via a narrative describing AQP functions during the life history of hematophagic arthropods that includes the following critical phases: (1) Saliva production necessary to blood feeding, (2) Intake and excretion of water during blood digestion, (3) Reproduction and egg development and (4) Off-host environmental stress tolerance. The concentration on these phases will highlight known vulnerabilities in the biology of hematophagic arthropods that could be used to develop novel control strategies as well as research topics that have yet to be examined.

  15. Insect Repellents: Reducing Insect Bites

    Science.gov (United States)

    ... Borne Illnesses Federal Trade Commission Action on Deceptive Marketing of Mosquito Repellent Wrist Band Joint Statement on ... Requests Frequent Questions Follow. Facebook Twitter YouTube Flickr Instagram Last updated on May 29, 2018

  16. Evaluation of a simple polytetrafluoroethylene (PTFE)-based membrane for blood-feeding of malaria and dengue fever vectors in the laboratory.

    Science.gov (United States)

    Siria, Doreen J; Batista, Elis P A; Opiyo, Mercy A; Melo, Elizangela F; Sumaye, Robert D; Ngowo, Halfan S; Eiras, Alvaro E; Okumu, Fredros O

    2018-04-11

    Controlled blood-feeding is essential for maintaining laboratory colonies of disease-transmitting mosquitoes and investigating pathogen transmission. We evaluated a low-cost artificial feeding (AF) method, as an alternative to direct human feeding (DHF), commonly used in mosquito laboratories. We applied thinly-stretched pieces of polytetrafluoroethylene (PTFE) membranes cut from locally available seal tape (i.e. plumbers tape, commonly used for sealing pipe threads in gasworks or waterworks). Approximately 4 ml of bovine blood was placed on the bottom surfaces of inverted Styrofoam cups and then the PTFE membranes were thinly stretched over the surfaces. The cups were filled with boiled water to keep the blood warm (~37 °C), and held over netting cages containing 3-4 day-old inseminated adults of female Aedes aegypti, Anopheles gambiae (s.s.) or Anopheles arabiensis. Blood-feeding success, fecundity and survival of mosquitoes maintained by this system were compared against DHF. Aedes aegypti achieved 100% feeding success on both AF and DHF, and also similar fecundity rates (13.1 ± 1.7 and 12.8 ± 1.0 eggs/mosquito respectively; P > 0.05). An. arabiensis had slightly lower feeding success on AF (85.83 ± 16.28%) than DHF (98.83 ± 2.29%) though these were not statistically different (P > 0.05), and also comparable fecundity between AF (8.82 ± 7.02) and DHF (8.02 ± 5.81). Similarly, for An. gambiae (s.s.), we observed a marginal difference in feeding success between AF (86.00 ± 10.86%) and DHF (98.92 ± 2.65%), but similar fecundity by either method. Compared to DHF, mosquitoes fed using AF survived a similar number of days [Hazard Ratios (HR) for Ae. aegypti = 0.99 (0.75-1.34), P > 0.05; An. arabiensis = 0.96 (0.75-1.22), P > 0.05; and An. gambiae (s.s.) = 1.03 (0.79-1.35), P > 0.05]. Mosquitoes fed via this simple AF method had similar feeding success, fecundity and longevity. The method could potentially be used for laboratory colonization of mosquitoes

  17. Insect repellent activity of medicinal plant oils against Aedes aegypti (Linn.), Anopheles minimus (Theobald) and Culex quinquefasciatus Say based on protection time and biting rate.

    Science.gov (United States)

    Phasomkusolsil, Siriporn; Soonwera, Mayura

    2010-07-01

    This study investigated insect bite protection and length of the protection with 30 repellents which were divided into 3 categories: plant oil, essential oil and essential oil with ethyl alcohol, tested against three mosquito species, Aedes aegypti, Anopheles minimus and Culex quinquefasciatus, under laboratory conditions. The plant oil group was comprised of Phlai (Zingiber cassumunar) and Sweet basil (Ocimum basilicum). Both substances were effective as repellents and feeding deterrents against An. minimus (205 minutes protection time and a biting rate of 0.9%), Cx. quinquefasciatus (165 minutes protection time and 0.9% biting rate) and Ae. aegypti (90 minutes protection time and 0.8% biting rate). Essential oil from citronella grass (Cymbopogon nardus) exhibited protection against biting from all 3 mosquito species: for An. minimus, Cx. quinquefasciatus and Ae. aegypti, the results were 130 minutes and 0.9%, 140 minutes and 0.8%, and 115 minutes and 0.8%, respectively. The period of protection time against Ae. aegypti for all repellent candidates tested was lower than the Thai Industrial Standards Institute (TISI) determined time of greater than 2 hours.

  18. Soil water repellency in north-eastern Greece with adverse effects of drying on the persistence

    NARCIS (Netherlands)

    Ziogas, A.K.; Dekker, L.W.; Oostindie, K.; Ritsema, C.J.

    2005-01-01

    Many soils may be water repellent to some degree, challenging the common perception that soil water repellency is only an interesting aberration. When dry, water repellent soils resist or retard water infiltration into the soil matrix. Soil water repellency often leads to the development of unstable

  19. Mosquito repellent properties of Delonix elata (L. gamble (Family: Fabaceae against filariasis vector, Culex quinquefasciatus Say. (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Marimuthu Govindarajan

    2014-02-01

    Full Text Available Objective: To determine the repellent activity of hexane, ethyl acetate, benzene, chloroform and methanol extract of Delonix elata (D. elata leaf and seed against Culex quinquefasciatus (Cx. quinquefasciatus. Methods: Evaluation was carried out in a net cage (45 cm伊30 cm伊25 cm containing 100 blood starved female mosquitoes of Cx. quinquefasciatus. Repellent activity was carried out in the laboratory conditions according to the WHO 2009 protocol. Plant crude extracts of D. elata were applied at 1.0, 2.5, and 5.0 mg/cm2 separately in the exposed fore arm of study subjects. Ethanol was used as the sole control. Results: In this study, the applied plant crude extracts were observed to protect against mosquito bites. There were no allergic reactions experienced by the study subjects. The repellent activity of the extract was dependent on the strength of the extract. Among the tested solvents, the leaf and seed methanol extract showed the maximum efficacy. The highest concentration of 5.0 mg/cm2 provided over 150 min and 120 min protection, respectively. Conclusions: Crude extracts of D. elata exhibit the potential for controlling Cx. quinquefasciatus, the mosquito vector of filariasis.

  20. Engineering Characteristics of Chemically Treated Water-Repellent Kaolin

    Directory of Open Access Journals (Sweden)

    Youngmin Choi

    2016-12-01

    Full Text Available Water-repellent soils have a potential as alternative construction materials that will improve conventional geotechnical structures. In this study, the potential of chemically treated water-repellent kaolin clay as a landfill cover material is explored by examining its characteristics including hydraulic and mechanical properties. In order to provide water repellency to the kaolin clay, the surface of clay particle is modified with organosilanes in concentrations (CO ranging from 0.5% to 10% by weight. As the CO increases, the specific gravity of treated clay tends to decrease, whereas the total organic carbon content of the treated clay tends to increase. The soil-water contact angle increases with an increase in CO until CO = 2.5%, and then maintains an almost constant value (≈134.0°. Resistance to water infiltration is improved by organosilane treatment under low hydrostatic pressure. However, water infiltration resistance under high hydrostatic pressure is reduced or exacerbated to the level of untreated clay. The maximum compacted dry weight density decreases with increasing CO. As the CO increases, the small strain shear modulus increases, whereas the effect of organosilane treatment on the constrained modulus is minimal. The results indicate that water-repellent kaolin clay possesses excellent engineering characteristics for a landfill cover material.

  1. Engineering Characteristics of Chemically Treated Water-Repellent Kaolin

    Science.gov (United States)

    Choi, Youngmin; Choo, Hyunwook; Yun, Tae Sup; Lee, Changho; Lee, Woojin

    2016-01-01

    Water-repellent soils have a potential as alternative construction materials that will improve conventional geotechnical structures. In this study, the potential of chemically treated water-repellent kaolin clay as a landfill cover material is explored by examining its characteristics including hydraulic and mechanical properties. In order to provide water repellency to the kaolin clay, the surface of clay particle is modified with organosilanes in concentrations (CO) ranging from 0.5% to 10% by weight. As the CO increases, the specific gravity of treated clay tends to decrease, whereas the total organic carbon content of the treated clay tends to increase. The soil-water contact angle increases with an increase in CO until CO = 2.5%, and then maintains an almost constant value (≈134.0°). Resistance to water infiltration is improved by organosilane treatment under low hydrostatic pressure. However, water infiltration resistance under high hydrostatic pressure is reduced or exacerbated to the level of untreated clay. The maximum compacted dry weight density decreases with increasing CO. As the CO increases, the small strain shear modulus increases, whereas the effect of organosilane treatment on the constrained modulus is minimal. The results indicate that water-repellent kaolin clay possesses excellent engineering characteristics for a landfill cover material. PMID:28774098

  2. INFLUENCE OF SELENIUM CONTENT AND OIL SOURCES IN FEED ON CONCENTRATION OF THYROID GLAND HORMONES AND ELECTROLYTE IN BROILER BLOOD

    Directory of Open Access Journals (Sweden)

    Zlata Kralik

    2014-12-01

    Full Text Available The research aimed to elaborate the influence of designed mixtures used in broilers fattening on the concentration of electrolytes and thyroid gland hormones in the blood.. The research was carried out on 120 male Ross 308 hybrid broilers. The fattening lasted for 42 days. During the first three weeks of fattening broilers were fed standard starter diet containing 22% crude protein and 13.90 MJ/kg ME. During the last three weeks of fattening, broilers were divided into 6 experimental groups, each fed specially prepared finisher diets (P1=6% sunflower oil+0.0 mg Se/kg of feed, P2=6% linseed oil+0.0 mg Se/kg of feed, P3=6% sunflower oil+0.3 mg Se/kg of feed, P4=6% linseed oil+0.3 mg Se/kg of feed, P5=6% sunflower oil+0.5 mg Se/kg of feed, P6=6% linseed oil+0.5 mg Se/kg of feed. Finisher diet was balanced at 18.02% crude protein and 14.40 MJ/kg ME. It was found out that the type of oil in chicken feed influenced to blood pH (P <0.001, whereas selenium level (P=0.014 in the feed, as well as the oil type and selenium level interaction (P<0.001 influenced the concentration of potassium in the blood. Oil type (P=0.037 influenced the concentration of fT3, which was lower in chickens fed mixtures with addition of linseed oil than in the chickens fed sunflower oil added mixtures. Interaction of selenium content and oil type had influence on differences in concentration of fT4 as well as on the ratio of fT3/fT4, (P<0.001, i.e. P=0.021. The research results indicated that oils supplemented to broiler diets and combined with different organic selenium concentrations affected pH, concentration of some electrolytes and thyroid gland hormones in broiler blood, however, all obtained values were within reference range for poultry.

  3. Physiological Responses, Growth Rate and Blood Metabolites Under Feed Restriction and Thermal Exposure in Kids

    Directory of Open Access Journals (Sweden)

    O.K. Hooda

    2014-05-01

    Full Text Available The study was carried out to study the cumulative effect of thermal stress and feed restriction in kids. Twelve kids of Alpine x Beetle cross were divided into two groups. Group 1 served as control and group 2 was put on restricted feeding and exposed at 40, 42 and 44oC. Body weights of both groups were similar before thermal exposure and feed restriction. Body weight of group 1 increased significantly and were higher than group 2 throughout the experiment. Body weight gain, average daily gain and feed conversion efficiency were comparable in both groups after removal of thermal stress and switching over to ad libitum feeding (42-63 days. Body weights of group 2 remained lower than group 1, the losses in body weights of group 2 could not be compensated and there was approximately 25% loss in body weight at the end of experiment. Physiological responses of group 2 were significantly lower before exposure to high temperature but increased significantly after exposure at temperature 40, 42 and 44oC and the increase was in commensurate with the increase in exposure temperature. Blood glucose, total protein, albumin and serum enzymes decreased significantly on exposure at higher temperature and differences were higher in feed restricted group. T3, T4 and cortisol concentration were similar in both groups before feed restriction and thermal stress. T3, T4 concentration decreased while cortisol concentration increased significantly after exposure to high temperature. Variations in plasma enzymes, acid phosphatase, alkaline phosphatase, SGOT and SGPT were not significant before feed restriction and thermal stress. The activities of acid phosphatase and alkaline phosphatase decreased whereas that of SGOT and SGPT increased significantly on exposure at temperature 40oC and subsequent changes at temperature 42 and 44oC were not significant. The study indicated that animals of group 2 experienced more stress as observed by significant alteration in body

  4. [Studies on reduction of repellent force of rare earth magnets--concerning tooth intrusion].

    Science.gov (United States)

    Kitsugi, A

    1992-12-01

    The purpose of this investigation was to evaluate the sealing effect of the repelling force of the magnets with ferromagnetic stainless steel and also to examine the reduction pattern along with the change of the relative position of the magnets. The Nd-Fe-B magnet as rare earth magnet, and SUSXM 27, YEP-3, SUS 416 as ferromagnetic stainless steel were used in this experiment. The findings were as follows: 1. There was a little decrease of the repelling force of the magnets sealed with ferromagnetic stainless steel. On the other hand, no significant differences in the repelling force sealed with any kind of ferromagnetic stainless steel were found. 2. Direct contact of the repelling force of the phi 4.0 x 1.5 mm magnets sealed with SUSXM 27 of 0.2 mm in thickness was 242 gf. According to relative horizontal 1.2 mm movement keeping direct contact, the vertical and horizontal components of the repelling force were of the same value. 3. The repelling force of the phi 10.0 x 1.8 mm magnets sealed with SUSXM 27 of 0.2 mm in thickness was 815 gf. It showed more than 300 gf of vertical component of the repelling force when the magnets shifted to 3.0 mm horizontally when in contact. 4. It is suggested that the repelling force of the Nd-Fe-B magnets will be clinically useful for the intrusion of molar teeth.

  5. Investigating the repellency of trifluoromethylphenyl amides analogues against Aedes aegypti

    Science.gov (United States)

    The purpose of this study is to develop new repellents and evaluate their efficacy for personal protection against mosquitoes. The minimum effective dosage (MED) was determined to estimate the lowest passing concentration of a repellent that prevents >99% of mosquito bites through a treated cloth. D...

  6. The feed gas composition determines the degree of physical plasma-induced platelet activation for blood coagulation

    Science.gov (United States)

    Bekeschus, Sander; Brüggemeier, Janik; Hackbarth, Christine; Weltmann, Klaus-Dieter; von Woedtke, Thomas; Partecke, Lars-Ivo; van der Linde, Julia

    2018-03-01

    Cold atmospheric (physical) plasma has long been suggested to be a useful tool for blood coagulation. However, the clinical applicability of this approach has not been addressed sufficiently. We have previously demonstrated the ability of a clinically accepted atmospheric pressure argon plasma jet (kINPen® MED) to coagulate liver incisions in mice with similar performance compared to the gold standard electrocauterization. We could show that plasma-mediated blood coagulation was dependent on platelet activation. In the present work, we extended on this by investigating kINPen®-mediated platelet activation in anticoagulated human donor blood ex vivo. With focus on establishing high-throughput, multi-parametric platelet activation assays and performing argon feed gas parameter studies we achieved the following results: (i) plasma activated platelets in heparinized but not in EDTA-anticoagulated blood; (ii) plasma decreased total platelet counts but increased numbers of microparticles; (iii) plasma elevated the expression of several surface activation markers on platelets (CD62P, CD63, CD69, and CD41/61); (iv) in platelet activation, wet and dry argon plasma outperformed feed gas admixtures with oxygen and/or nitrogen; (v) plasma-mediated platelet activation was accompanied by platelet aggregation. Platelet aggregation is a necessary requirement for blood clot formation. These findings are important to further elucidate molecular details and clinical feasibility of cold physical plasma-mediated blood coagulation.

  7. Prevention of vector transmitted diseases with clove oil insect repellent.

    Science.gov (United States)

    Shapiro, Rochel

    2012-08-01

    Vector repellent is one element in the prevention of vector-borne diseases. Families that neglect protecting their children against vectors risk their children contracting illnesses such as West Nile virus, eastern equine encephalitis, Lyme disease, malaria, dengue hemorrhagic fever, yellow fever, babesiosis, Crimean-Congo hemorrhagic fever, Rocky Mountain spotted fever, Southern tick-associated rash illness, ehrlichiosis, tick-borne relapsing fever, tularemia, and other insect and arthropod related diseases (CDC, 2011). Identification of families at risk includes screening of the underlying basis for reluctance to apply insect repellent. Nurses and physicians can participate in a positive role by assisting families to determine the proper prophylaxis by recommending insect repellent choices that are economical, safe, and easy to use. A holistic alternative might include the suggestion of clove oil in cases where families might have trepidations regarding the use of DEET on children. This article will explore the safety and effectiveness of clove oil and its use as an insect repellent. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Frequent blood feeding enables insecticide-treated nets to reduce transmission by mosquitoes that bite predominately outdoors.

    Science.gov (United States)

    Russell, Tanya L; Beebe, Nigel W; Bugoro, Hugo; Apairamo, Allan; Chow, Weng K; Cooper, Robert D; Collins, Frank H; Lobo, Neil F; Burkot, Thomas R

    2016-03-10

    The effectiveness of vector control on malaria transmission by long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) depends on the vectors entering houses to blood feed and rest when people are inside houses. In the Solomon Islands, significant reductions in malaria have been achieved in the past 20 years with insecticide-treated bed nets, IRS, improved diagnosis and treatment with artemisinin combination therapies; despite the preference of the primary vector, Anopheles farauti, to feed outdoors and early in the evening and thereby avoid potential exposure to insecticides. Rational development of tools to complement LLINs and IRS by attacking vectors outdoor requires detailed knowledge of the biology and behaviours of the target species. Malaria transmission in Central Province, Solomon Islands was estimated by measuring the components comprising the entomological inoculation rate (EIR) as well as the vectorial capacity of An. farauti. In addition, the daily and seasonal biting behaviour of An. farauti, was examined and the duration of the feeding cycle was estimated with a mark-release-recapture experiment. Anopheles farauti was highly exophagic with 72% captured by human landing catches (HLC) outside of houses. Three-quarters (76%) of blood feeding on humans was estimated to occur before 21.00 h. When the hourly location of humans was considered, the proportion of exposure to mosquito bites on humans occurring indoors (πi) was only 0.130 ± 0.129. Peak densities of host seeking An. farauti occurred between October and January. The annual EIR was estimated to be 2.5 for 2012 and 33.2 for 2013. The length of the feeding cycle was 2.1 days. The short duration of the feeding cycle by this species offers an explanation for the substantial control of malaria that has been achieved in the Solomon Islands by LLINs and IRS. Anopheles farauti is primarily exophagic and early biting, with 13% of mosquitoes entering houses to feed late at night during

  9. Application of Super-Hydrophobic Coating for Enhanced Water Repellency of Ballistic Fabric

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Barton [ORNL; Rajic, Slobodan [ORNL; Hunter, Scott Robert [ORNL

    2014-10-01

    The objective of this work was to demonstrate that a superhydrophobic coating technology developed at Oak Ridge National Laboratory (ORNL) increases the water repellency of ballistic fabric beyond that provided by existing water repellency treatments. This increased water repellency has the potential to provide durable ballistic fabric for body armor without adding significant weight to the armor or significant manufacturing cost. Specimens of greige and scoured ballistic fabric were treated with a superhydrophobic coating and their weights and degree of water repellency were compared to specimens of untreated fabric. Treatment of both greige and scoured ballistic fabrics yielded highly water repellent fabrics. Our measurements of the water droplet contact angles gave values of approximately 150 , near the lower limit of 160 for superhydrophobic surfaces. The coatings increased the fabric weights by approximately 6%, an amount that is many times less than the estimated weight increase in a conventional treatment of ballistic fabric. The treated fabrics retained a significant amount of water repellency following a basic abrasion test, with water droplet contact angles decreasing by 14 to 23 . Microscopic analysis of the coating applied to woven fabrics indicated that the coating adhered equally well to fibers of greige and scoured yarns. Future evaluation of the superhydrophobic water repellent treatment will involve the manufacture of shoot packs of treated fabric for ballistic testing and provide an analysis of manufacturing scale-up and cost-to-benefit considerations.

  10. Repellent Activity of Apiaceae Plant Essential Oils and their Constituents Against Adult German Cockroaches.

    Science.gov (United States)

    Lee, Hyo-Rim; Kim, Gil-Hah; Choi, Won-Sil; Park, Il-Kwon

    2017-04-01

    We evaluated the repellent activity of 12 Apiaceae plant essential oils and their components against male and female adult German cockroaches, Blattella germanica L., to find new natural repellents. Of all the plant essential oils tested, ajowan (Trachyspermum ammi Sprague) and dill (Anethum graveolens L.) essential oils showed the most potent repellent activity against male and female adult German cockroaches. Repellent activities of chemicals already identified in active oils were also investigated. Of the compounds identified, carvacrol, thymol, and R-(-)-carvone showed >80% repellent activity against male and female adult German cockroaches at 2.5 µg/cm2. S-(+)-Carvone, (+)-dihydrocarvone, and terpinen-4-ol showed >70% repellent activity against male and female adult German cockroaches at 10 µg/cm2. Our results indicated that Apiaceae plant essential oils and their constituents have good potential as natural repellents against adult German cockroaches. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Zein Nanoparticles as Eco-Friendly Carrier Systems for Botanical Repellents Aiming Sustainable Agriculture.

    Science.gov (United States)

    Oliveira, Jhones L de; Campos, Estefânia V R; Pereira, Anderson E S; Pasquoto, Tatiane; Lima, Renata; Grillo, Renato; Andrade, Daniel Junior de; Santos, Fabiano Aparecido Dos; Fraceto, Leonardo Fernandes

    2018-02-14

    Botanical repellents represent one of the main ways of reducing the use of synthetic pesticides and the contamination of soil and hydric resources. However, the poor stability and rapid degradation of these compounds in the environment hinder their effective application in the field. Zein nanoparticles can be used as eco-friendly carrier systems to protect these substances against premature degradation, provide desirable release characteristics, and reduce toxicity in the environment and to humans. In this study, we describe the preparation and characterization of zein nanoparticles loaded with the main constituents of the essential oil of citronella (geraniol and R-citronellal). The phytotoxicity, cytotoxicity, and insect activity of the nanoparticles toward target and nontarget organisms were also evaluated. The botanical formulations showed high encapsulation efficiency (>90%) in the nanoparticles, good physicochemical stability, and effective protection of the repellents against UV degradation. Cytotoxicity and phytotoxicity assays showed that encapsulation of the botanical repellents decreased their toxicity. Repellent activity tests showed that nanoparticles containing the botanical repellents were highly repellent against the Tetranychus urticae Koch mite. This nanotechnological formulation offers a new option for the effective use of botanical repellents in agriculture, reducing toxicity, protecting against premature degradation, and providing effective pest control.

  12. The neonicotinoid insecticide imidacloprid repels pollinating flies and beetles at field-realistic concentrations.

    Directory of Open Access Journals (Sweden)

    Amy H Easton

    Full Text Available Neonicotinoids are widely used systemic insecticides which, when applied to flowering crops, are translocated to the nectar and pollen where they may impact upon pollinators. Given global concerns over pollinator declines, this potential impact has recently received much attention. Field exposure of pollinators to neonicotinoids depends on the concentrations present in flowering crops and the degree to which pollinators choose to feed upon them. Here we describe a simple experiment using paired yellow pan traps with or without insecticide to assess whether the commonly used neonicotinoid imidacloprid repels or attracts flying insects. Both Diptera and Coleoptera exhibited marked avoidance of traps containing imidacloprid at a field-realistic dose of 1 µg L(-1, with Diptera avoiding concentrations as low as 0.01 µg L(-1. This is to our knowledge the first evidence for any biological activity at such low concentrations, which are below the limits of laboratory detection using most commonly available techniques. Catch of spiders in pan traps was also slightly reduced by the highest concentrations of imidacloprid used (1 µg L(-1, but catch was increased by lower concentrations. It remains to be seen if the repellent effect on insects occurs when neonicotinoids are present in real flowers, but if so then this could have implications for exposure of pollinators to neonicotinoids and for crop pollination.

  13. Blood meal identification and feeding habits of uranotaenia species collected in the ryukyu archipelago.

    Science.gov (United States)

    Toma, Takako; Miyagi, Ichiro; Tamashiro, Mikako

    2014-09-01

    To know the blood meal in the stomach of Uranotaenia species, blood-fed mosquitoes were collected by 4 methods at different sites in the mountain forest of 3 islands, Amamioshima, Okinawajima, and Iriomotejima in the Ryukyu Archipelago, Japan from 2005 to 2012. One hundred twenty-four blood-fed Uranotaenia mosquitoes of 7 species (Ur. jacksoni, nivipleura, ohamai, yaeyamana, annandalei, lateralis, and macfarlanei) were collected. The collection rates are 0.26, 0.6, 0.31, and 0.66 by black light trap, black light blue with dry ice trap, frog call trap, and sweeping net, respectively. The blood meals of 107 females (86.3%) were successfully identified by a polymerase chain reaction-based method. All Uranotaenia species fed on cold-blooded animals, especially amphibians (99.1%), and notably on frogs. They would feed readily on available frogs in a given region having no close connection with the breeding (calling) season of each frog. They also fed on reptiles (0.9%), but not on warm-blooded animals.

  14. Are commercially available essential oils from Australian native plants repellent to mosquitoes?

    Science.gov (United States)

    Maguranyi, Suzann K; Webb, Cameron E; Mansfield, Sarah; Russell, Richard C

    2009-09-01

    While the use of topical insect repellents, particularly those containing synthetic active ingredients such as deet (N,N-diethyl-3-methylbenzamide), are a mainstay in personal protection strategies emphasized in public health messages, there is a growing demand in the community for alternative repellents, particularly those of botanical origin and thus deemed to be "natural." This study evaluated the repellency of essential oils from 11 Australian native plants in 5% v/v formulations against Aedes aegypti, Culex quinquefasciatus, and Culex annulirostris under laboratory conditions. A blend of the top 3 performing oils was then compared with deet and a commercially available botanical insect repellent. All essential oils provided at least some protection against the 3 mosquito species, with the longest protection time (110 min) afforded by Prostanthera melissifolia against Cx. quinquefasciatus. Mean protection times against Ae. aegypti were substantially lower than those for the Culex spp. tested. Deet provided significantly longer protection against Ae. aegypti than both the 5% v/v blend of Leptospermum petersonii, Prostanthera melissifolia, and Melaleuca alternifolia (the 3 most effective oils) and the commercial botanical repellent. The results of this study indicate that these essential oils from Australian native plants offer limited protection against biting mosquitoes and that a blend of essential oils holds may offer commercial potential as a short-period repellent or under conditions of low mosquito abundance. However, it is important that public health messages continue to emphasize the greater effectiveness of deet-based repellents in areas with risks of mosquito-borne disease.

  15. Experimental Investigation of Evaporation and Drainage in Wettable and Water-Repellent Sands

    Directory of Open Access Journals (Sweden)

    Dae Hyun Kim

    2015-05-01

    Full Text Available This study presents experimental results on evaporation and drainage in both wettable and water-repellent sands whose surface wettability was artificially modified by silanization. The 2D optical and 3D X-ray computed tomographic imaging was performed during evaporation and the water retention during cyclic drainage and infiltration was measured to assess effects of wettability and initial wetting conditions. The evaporation gradually induces its front at the early stage advance regardless of the wettability and sand types, while its rate becomes higher in water-repellent Ottawa sand than the wettable one. Jumunjin sand which has a smaller particle size and irregular particle shape than Ottawa sand exhibits a similar evaporation rate independent of wettability. Water-repellent sand can facilitate the evaporation when both wettable and water-repellent sands are naturally in contact with each other. The 3D X-ray imaging reveals that the hydraulically connected water films in wettable sands facilitate the propagation of the evaporation front into the soil such that the drying front deeply advances into the soil. For cyclic drainage-infiltration testing, the evolution of water retention is similar in both wettable and water-repellent sands when both are initially wet. However, when conditions are initially dry, water-repellent sands exhibit low residual saturation values. The experimental observations made from this study propose that the surface wettability may not be a sole factor while the degree of water-repellency, type of sands, and initial wetting condition are predominant when assessing evaporation and drainage behaviors.

  16. From Chemistry to Behavior. Molecular Structure and Bioactivity of Repellents against Ixodes ricinus Ticks.

    Directory of Open Access Journals (Sweden)

    Simone Del Fabbro

    Full Text Available Tick-borne zoonoses are considered as emerging diseases. Tick repellents represent an effective tool for reducing the risk of tick bite and pathogens transmission. Previous work demonstrated the repellent activity of the phenylpropanoid eugenol against Ixodes ricinus; here we investigate the relationship between molecular structure and repellency in a group of substances related to that compound. We report the biological activity of 18 compounds varying for the presence/number of several moieties, including hydroxyl and methoxy groups and carbon side-chain. Each compound was tested at different doses with a bioassay designed to measure repellency against individual tick nymphs. Both vapor pressure and chemical features of the tested compounds appeared to be related to repellency. In particular, the hydroxyl and methoxy groups as well as the side-chain on the benzene ring seem to play a role. These results are discussed in light of available data on chemical perception in ticks. In the course of the study new repellent compounds were identified; the biological activity of some of them (at least as effective as the "gold standard" repellent DEET appears to be very promising from a practical point of view.

  17. [Repellent activity of plant essential oils against bites of Lutzomyia migonei (Diptera: Psychodidae)].

    Science.gov (United States)

    Nieves, Elsa; Fernández Méndez, Janett; Lias, José; Rondón, Maritza; Briceño, Benito

    2010-12-01

    Natural repellents from plant extracts have demonstrated good efficacy against bites of some insect species. The present study evaluated the repellent effect of essential oils extracted from 8 plants species against bites of Lutzomyia migonei, the Leishmania vector. The essential oils were extracted by steam destillation in Clevenger chamber, from the following plants: Hyptis suaveolens, Pimenta racemosa, Piper marginatum, Monticalia imbricatifolia, Pseudognaphalium caeruleocanum, Espeletia shultzii, Plecthranthus amboinicus and Cinnamomun zeylanicum. Repellency tests were performed under laboratory conditions by the human hand method in cage assays, using female colonies of L. migonei. The more effective oils were tested at variable concentrations on different volunteers. The protection percentage and time were calculated. The results showed what oils of P. caeruleocanum and C. zeylanicum were the most effective. Although P. amboinicus oil also had repellent effect showed an irritant effect. The oils P. marginatum, H. suaveolens and P. racemosa showed no repellent effect, while the rest of oil extracts showed significant repellency in variable degrees. P. caeruleocanum and C. zeylanicum oils provided the 95% protection against bites of L. migonei for 3 h. The P. caeruleocanum oil showed the greatest protection time, with a mean over 4h and 3h at concentrations of 50% and 10% respectively. The results suggest that the P. caeruleocanum oil could represent a potential natural repellent against Leishmania vectors.

  18. Dietary sodium bicarbonate, cool temperatures, and feed withdrawal: impact on arterial and venous blood-gas values in broilers.

    Science.gov (United States)

    Wideman, R F; Hooge, D M; Cummings, K R

    2003-04-01

    Sodium bicarbonate (NaHCO3) has been used successfully in mammals and birds to alleviate pulmonary hypertension. Experiment 1 was designed to provide measurements of arterial and venous blood-gas values from unanesthetized male broilers subjected to a cool temperature (16 degrees C) challenge and fed either a control diet or the same diet alkalinized by dilution with 1% NaHCO3. The incidences of pulmonary hypertension syndrome (PHS, ascites) for broilers fed the control or bicarbonate diets were 15.5 and 10.5%, respectively (P = 0.36, NS). Non-ascitic broilers fed the control diet were heavier than those fed the bicarbonate diet on d 49 (2,671 vs. 2,484 g, respectively); however, other comparisons failed to reveal diet-related differences in heart weight, pulse oximetry values, electrocardiogram amplitudes, or blood-gas values (P > 0.05). When the data were resorted into categories based on right:total ventricular weight ratios (RV:TV) indicative of normal (RV:TV or = 0.28) pulmonary arterial pressures, broilers with elevated RV:TV ratios had poorly oxygenated arterial blood that was more acidic, had high partial pressure of CO2 (PCO2), and had higher HCO3 concentrations when compared with broilers with normal RV:TV ratios. Experiment 2 was conducted to determine if metabolic variations associated with differences in feed intake or environmental temperature potentially could mask an impact of diet composition on blood-gas values. Male broilers maintained at thermoneutral temperature (24 degrees C) either received feed ad libitum or had the feed withdrawn > or = 12 h prior to blood sampling. Broilers fed ad libitum had lower venous saturation of hemoglobin with O2, higher venous PCO2, and higher arterial HCO3 concentrations than broilers subjected to feed withdrawal. Broilers in experiment 2 fed ad libitum and exposed to cool temperatures (16 degrees C) had lower arterial partial pressure of O2 and higher venous PCO2 than broilers fed ad libitum and maintained at 24

  19. Sialotranscriptomics of Rhipicephalus zambeziensis reveals intricate expression profiles of secretory proteins and suggests tight temporal transcriptional regulation during blood-feeding.

    Science.gov (United States)

    de Castro, Minique Hilda; de Klerk, Daniel; Pienaar, Ronel; Rees, D Jasper G; Mans, Ben J

    2017-08-10

    Ticks secrete a diverse mixture of secretory proteins into the host to evade its immune response and facilitate blood-feeding, making secretory proteins attractive targets for the production of recombinant anti-tick vaccines. The largely neglected tick species, Rhipicephalus zambeziensis, is an efficient vector of Theileria parva in southern Africa but its available sequence information is limited. Next generation sequencing has advanced sequence availability for ticks in recent years and has assisted the characterisation of secretory proteins. This study focused on the de novo assembly and annotation of the salivary gland transcriptome of R. zambeziensis and the temporal expression of secretory protein transcripts in female and male ticks, before the onset of feeding and during early and late feeding. The sialotranscriptome of R. zambeziensis yielded 23,631 transcripts from which 13,584 non-redundant proteins were predicted. Eighty-six percent of these contained a predicted start and stop codon and were estimated to be putatively full-length proteins. A fifth (2569) of the predicted proteins were annotated as putative secretory proteins and explained 52% of the expression in the transcriptome. Expression analyses revealed that 2832 transcripts were differentially expressed among feeding time points and 1209 between the tick sexes. The expression analyses further indicated that 57% of the annotated secretory protein transcripts were differentially expressed. Dynamic expression profiles of secretory protein transcripts were observed during feeding of female ticks. Whereby a number of transcripts were upregulated during early feeding, presumably for feeding site establishment and then during late feeding, 52% of these were downregulated, indicating that transcripts were required at specific feeding stages. This suggested that secretory proteins are under stringent transcriptional regulation that fine-tunes their expression in salivary glands during feeding. No open

  20. Longitudinal evaluation of Ocimum and other plants effects on the feeding behavioral response of mosquitoes (Diptera: Culicidae in the field in Tanzania

    Directory of Open Access Journals (Sweden)

    Tenu Filemoni

    2008-10-01

    Full Text Available Abstract Background The use of repellent materials from plants against nuisance insects is common with great potential to compliment existing malaria control programmes and this requires evaluation in the field. Ocimum plant species, Ocimum suave (Willd and O. kilimandscharicum (Guerke materials and their essential oils extracted by steam distillation were evaluated in the field and experimental huts for repellence, exophily and feeding inhibition effects against three mosquito species, Anopheles arabiensis (Patton, An. gambiae ss (Giles and Culex quinquefasciatus (Say. The protective effect of essential oils from Ocimum plants were compared with N, N-diethly-3- methylbenzamide (DEET, a standard synthetic repellent. Also, the protective effect of fumigation by burning of repellent plants; Ocimum suave, Ocimum kilimandscharicum, Azadirachta indica, Eucalyptus globules and Lantana camara were tested in experimental huts and selected local houses. Results In the field, protection by Ocimum plants from mosquito bites was high and there was small variation among different mosquito species. Protection efficiency was 93.4%, 91.98% and 89.75% for An. arabiensis while for Cx. quinquefaciatus it was 91.30%, 88.65% and 90.50% for DEET, Ocimum suave and O. kilimandscharicum respectively. In the experimental hut, deterrence induced by burning of Ocimum and other plants ranged from 73.1.0% to 81.9% for An. arabiensis and 56.5% to 67.8% for Cx. quinquefaciatus, while feeding inhibition was 61.1% to 100% for An. arabiensis and 50% to 100% for Cx. quinquefaciatus. Evaluations under field conditions confirmed high protective efficacy, enhanced feeding inhibition and house entry inhibition (Deterrence. Conclusion This study shows the potential of Ocimum suave and Ocimum kilimandscharicum crude extracts and whole plants of Ocimum suave, Ocimum kilimandscharicum, Azadirachta indica, Eucalyptus globules and Lantana camara for use in protecting against human biting

  1. Repellent Activity of TRIG (N-N Diethyl Benzamide against Man-Biting Mosquitoes

    Directory of Open Access Journals (Sweden)

    Shandala Msangi

    2018-01-01

    Full Text Available A study was conducted to assess efficacy of a new repellent brand TRIG (15% N-N Diethyl Benzamide when compared to DEET (20% N-N Methyl Toluamide. The repellents were tested in laboratory and field. In the laboratory, the repellence was tested on human volunteers, by exposing their repellent-treated arms on starved mosquitoes in cages for 3 minutes at hourly intervals, while counting the landing and probing attempts. Anopheles gambiae and Aedes aegypti mosquitoes were used. Field evaluation was conducted by Human Landing Catch technique. During the night, the repellents were applied on arms and legs and mosquitoes landing on these areas were collected. In laboratory tests, TRIG provided complete protection (100% against Anopheles gambiae when applied at 1.25 g, while DEET provided this at 0.75 g. When tested on Aedes aegypti, TRIG provided complete protection when applied at 1 g, compared to 0.5 g for DEET. In the field, when applied at a recommended dose, both TRIG and DEET achieved above 90% protection against both An. arabiensis and Culex quinquefasciatus and a Complete Protection Time of about 6 hrs against both species of mosquitoes. The performances of the two products were found to be comparable and TRIG was recommended for use as repellent against mosquito bites.

  2. Repellent Activity of TRIG (N-N Diethyl Benzamide) against Man-Biting Mosquitoes.

    Science.gov (United States)

    Msangi, Shandala; Kweka, Eliningaya; Mahande, Aneth

    2018-01-01

    A study was conducted to assess efficacy of a new repellent brand TRIG (15% N-N Diethyl Benzamide) when compared to DEET (20% N-N Methyl Toluamide). The repellents were tested in laboratory and field. In the laboratory, the repellence was tested on human volunteers, by exposing their repellent-treated arms on starved mosquitoes in cages for 3 minutes at hourly intervals, while counting the landing and probing attempts. Anopheles gambiae and Aedes aegypti mosquitoes were used. Field evaluation was conducted by Human Landing Catch technique. During the night, the repellents were applied on arms and legs and mosquitoes landing on these areas were collected. In laboratory tests, TRIG provided complete protection (100%) against Anopheles gambiae when applied at 1.25 g, while DEET provided this at 0.75 g. When tested on Aedes aegypti, TRIG provided complete protection when applied at 1 g, compared to 0.5 g for DEET. In the field, when applied at a recommended dose, both TRIG and DEET achieved above 90% protection against both An. arabiensis and Culex quinquefasciatus and a Complete Protection Time of about 6 hrs against both species of mosquitoes. The performances of the two products were found to be comparable and TRIG was recommended for use as repellent against mosquito bites.

  3. Repellent activity of monoterpenoid esters with neurotransmitter amino acids against yellow fever mosquito, Aedes aegypti

    Directory of Open Access Journals (Sweden)

    Nesterkina Mariia

    2018-03-01

    Full Text Available Repellent activity of monoterpenoid esters (1-6 with neurotransmitter amino acids (GABA and glycine was investigated against Aedes aegypti by using a “cloth-patch” assay and compared to reference standard N,N-diethyl-3-methylbenzamide (DEET. Monoterpenoid esters showed repellent activity with minimum effective dosages (MED in the range of 0.031-0.469 mg/cm2. The carvacrol ester of GABA (2, MED of 0.031 ± 0.008 mg/cm2 exhibited the highest repellency of six monoterpenoid esters tested in comparison to the standard repellent DEET (MED of 0.009 ± 0.002 mg/cm2; however, the repellent activity of carvacrol-glycine ester (5 decreased 4-fold compared to the carvacrol-GABA derivative (2. The repellent activities of menthol GABA (1, MED= 0.375 ± 0.000 mg/cm2 and glycine ester (4, MED=0.312 ± 0.063 mg/cm2 were similar The guaiacol-glycine ester (6 was 3.75-fold more efficacious than the guaiacol ester of GABA (3. In the present study, we report repellent efficacy of prolonged exposure to GABA and glycine esters of menthol, carvacrol, guaiacol (1-6 as compared to the repellent activities of their monoterpene moieties alone.

  4. β-caryophyllene emitted from a transgenic Arabidopsis or chemical dispenser repels Diaphorina citri, vector of Candidatus Liberibacters.

    Science.gov (United States)

    Alquézar, Berta; Volpe, Haroldo Xavier Linhares; Magnani, Rodrigo Facchini; de Miranda, Marcelo Pedreira; Santos, Mateus Almeida; Wulff, Nelson Arno; Bento, Jose Mauricio Simões; Parra, José Roberto Postali; Bouwmeester, Harro; Peña, Leandro

    2017-07-17

    Production of citrus, the main fruit tree crop worldwide, is severely threatened by Huanglongbing (HLB), for which as yet a cure is not available. Spread of this bacterial disease in America and Asia is intimately connected with dispersal and feeding of the insect vector Diaphorina citri, oligophagous on rutaceous host plants. Effective control of this psyllid is an important component in successful HLB management programs. Volatiles released from the non-host guava have been shown to be repellent to the psyllid and to inhibit its response to citrus odour. By analysing VOC emission from guava we identified one volatile compound, (E)-β-caryophyllene, which at certain doses exerts a repellent effect on D. citri. Non-host plant rejection mediated by (E)-β-caryophyllene is demonstrated here by using Arabidopsis over-expression and knock-out lines. For the first time, results indicate that genetically engineered Arabidopsis plants with modified emission of VOCs can alter the behaviour of D. citri. This study shows that transgenic plants with an inherent ability to release (E)-β-caryophyllene can potentially be used in new protection strategies of citrus trees against HLB.

  5. Effects of temperature on development, mortality, mating and blood feeding behavior of Culiseta incidens (Diptera: Culicidae).

    Science.gov (United States)

    Su, T; Mulla, M S

    2001-06-01

    Culiseta incidens Thomson is distributed over most of the western USA and Canada northward to Alaska. Because this mosquito is difficult to colonize, its biology has not been well investigated. We colonized this species in 1998 and studied the effects of temperature on various aspects of its life cycle. The time required for egg melanization and the duration of the egg stage were negatively correlated with temperature. The proportion of fertile egg rafts was temperature-independent. An inverse relationship existed between temperature and egg hatch. Molting and stadium duration after hatching were temperature-dependent, with higher temperature accelerating development and molting. Larvae and pupae experienced lower mortality and higher molting success at lower temperatures. Survivorship of adult mosquitoes fed on sugar solution was inversely proportional to temperature, lethal times for 50% mortality (LT50) were greater at the lower temperature than at the higher temperature. Females survived longer than did males at all test temperatures. Because this species is eurygamous, mating only occurred in large cages. Mating success was also affected by temperature. At the test temperatures, 20 degrees C, 25 degrees C and 30 degrees C, mating started from 3-5 days after emergence and reached a peak on days 13-15 after emergence. Maximum mating rates at 20 degrees C and 25 degrees C were higher than at 30 degrees C. Blood feeding, as indicated by cumulative feeding rates, was affected by cage size, mosquito age and temperature. Mosquitoes in large cages exhibited a much higher feeding rate than in small cages. With age, the cumulative blood feeding rate increased, with the highest rate at 25 degrees C, followed by 20 degrees C and 30 degrees C. At all temperatures tested, most of the blood fed females were mated.

  6. Using Insect Repellents Safely and Effectively

    Science.gov (United States)

    ... Directory Planning, Budget and Results Jobs and Internships Headquarters Offices Regional Offices Labs and Research Centers Related ... repellent product label. This registration number means the company provided EPA with technical information on the effectiveness ...

  7. Insecticidal, repellent and fungicidal properties of novel trifluoromethylphenyl amides.

    Science.gov (United States)

    Tsikolia, Maia; Bernier, Ulrich R; Coy, Monique R; Chalaire, Katelyn C; Becnel, James J; Agramonte, Natasha M; Tabanca, Nurhayat; Wedge, David E; Clark, Gary G; Linthicum, Kenneth J; Swale, Daniel R; Bloomquist, Jeffrey R

    2013-09-01

    Twenty trifluoromethylphenyl amides were synthesized and evaluated as fungicides and as mosquito toxicants and repellents. Against Aedes aegypti larvae, N-(2,6-dichloro-4-(trifluoromethyl)phenyl)-3,5-dinitrobenzamide (1e) was the most toxic compound (24 h LC50 1940 nM), while against adults N-(2,6-dichloro-4-(trifluoromethyl)phenyl)-2,2,2-trifluoroacetamide (1c) was most active (24 h LD50 19.182 nM, 0.5 μL/insect). However, the 24 h LC50 and LD50 values of fipronil against Ae. aegypti larvae and adults were significantly lower: 13.55 nM and 0.787 × 10(-4) nM, respectively. Compound 1c was also active against Drosophila melanogaster adults with 24 h LC50 values of 5.6 and 4.9 μg/cm(2) for the Oregon-R and 1675 strains, respectively. Fipronil had LC50 values of 0.004 and 0.017 μg/cm(2) against the two strains of D. melanogaster, respectively. In repellency bioassays against female Ae. aegypti, 2,2,2-trifluoro-N-(2-(trifluoromethyl)phenyl)acetamide (4c) had the highest repellent potency with a minimum effective dosage (MED) of 0.039 μmol/cm(2) compared to DEET (MED of 0.091 μmol/cm(2)). Compound N-(2-(trifluoromethyl)phenyl)hexanamide (4a) had an MED of 0.091 μmol/cm(2) which was comparable to DEET. Compound 4c was the most potent fungicide against Phomopsis obscurans. Several trends were discerned between the structural configuration of these molecules and the effect of structural changes on toxicity and repellency. Para- or meta- trifluoromethylphenyl amides with an aromatic ring attached to the carbonyl carbon showed higher toxicity against Ae. aegypti larvae, than ortho- trifluoromethylphenyl amides. Ortho- trifluoromethylphenyl amides with trifluoromethyl or alkyl group attached to the carbonyl carbon produced higher repellent activity against female Ae. aegypti and Anopheles albimanus than meta- or para- trifluoromethylphenyl amides. The presence of 2,6-dichloro- substitution on the phenyl ring of the amide had an influence on larvicidal and repellent

  8. Celery-based topical repellents as a potential natural alternative for personal protection against mosquitoes.

    Science.gov (United States)

    Tuetun, B; Choochote, W; Pongpaibul, Y; Junkum, A; Kanjanapothi, D; Chaithong, U; Jitpakdi, A; Riyong, D; Pitasawat, B

    2008-12-01

    Celery-based products were investigated for chemical composition, skin irritation, and mosquito repellency in comparison to commercial repellents and the standard chemical, N,N-diethyl-3-methylbenzamide (DEET), with a goal to develop a natural alternative to synthetic repellents for protection against mosquitoes. Chemical identification by gas chromatography coupled with mass spectrometry discovered that the major constituents of Apium graveolens hexane extract (AHE) were 3-n-butyl-tetrahydrophthalide (92.48%), followed by 5.10% beta-selinene and 0.68% gamma-selinene. Evaluation of skin irritation in 27 human volunteers revealed no irritant potential from 25% ethanolic AHE solution. Laboratory investigated repellent against female Aedes aegypti mosquitoes demonstrated that G10 formula, the best AHE-developed product, provided remarkable repellency with a median protection time of 4.5 h (4.5-5 h), which was greater than that of ethanolic DEET solution (25% DEET, 3.5 h) and comparable to that of the best commercial repellent, Insect Block 28 (28.5% DEET, 4.5 h). According to significantly promising results, including highly effective repellency and no potential skin irritation or other side effects, the G10 formula is a worthwhile product that has the promise of being developed for commercialized registration. This developed AHE product could be an acceptable and affordable alternative to conventional synthetic chemicals in preventing mosquito bites, and in turn, helping to interrupt mosquito-borne disease transmission.

  9. Adult mortality and blood feeding behavioral effects of α-amyrin acetate, a novel bioactive compound on in vivo exposed females of Anopheles stephensi Liston (Diptera: Culicidae).

    Science.gov (United States)

    Chenniappan, Kuppusamy; Kadarkari, Murugan

    2012-06-01

    The effect of α-amyrin acetate on mortality and blood feeding behavior in females of Anopheles stephensi was assessed by in vivo exposure on treated guinea pig skin. In vivo exposure to α-amyrin acetate caused mosquito knock down in the form of rapidly and normally reversible paralysis and the subsequent record at the end of a 24 h, revealed mortality rates of females increased from 0.0% (Control) to 76.9% at 1.6% α-amyrin acetate, the highest concentration which implies the contact toxicity of the α-amyrin acetate received through the sensitive parts of test species. The mean probing time responses significantly increased (P blood feeding rates and the mean engorgement times were significantly shorter when compared to the control. The mean blood feeding rates of exposed females decreased from 91.7% (control) to 41.5% at 0.8% α-amyrin acetate concentrations, the mean engorgement time also decreased from 278.6 s (Control) to 158.7 s at 0.8% α-amyrin acetate concentrations. Mean blood feeding rates and mean engorgement time were statistically significant (P blood meal size have played a more important role in decline of fecundity. In vivo exposure to α-amyrin acetate caused increased mean probing time, decreased blood engorgement time and feeding rate and declined fecundity which reduce the overall survival and reproductive capacity of the malaria vector A. stephensi.

  10. The influence of compost addition on the water repellency of brownfield soils

    Science.gov (United States)

    Whelan, Amii; Kechavarzi, Cedric; Sakrabani, Ruben; Coulon, Frederic; Simmons, Robert; Wu, Guozhong

    2010-05-01

    Compost application to brownfield sites, which can facilitate the stabilisation and remediation of contaminants whilst providing adequate conditions for plant growth, is seen as an opportunity to divert biodegradable wastes from landfill and put degraded land back into productive use. However, although compost application is thought to improve soil hydraulic functioning, there is a lack of information on the impact of large amounts of compost on soil water repellency. Water repellency in soils is attributed to the accumulation of hydrophobic organic compounds released as root exudates, fungal and microbial by-products and decomposition of organic matter. It has also been shown that brownfield soils contaminated with petroleum-derived organic contaminants can exhibit strong water repellency, preventing the rapid infiltration of water and leading potentially to surface run off and erosion of contaminated soil. However, hydrophobic organic contaminants are known to become sequestrated by partitioning into organic matter or diffusing into nano- and micropores, making them less available over time (ageing). The effect of large amounts of organic matter addition through compost application on the water repellency of soils contaminated with petroleum-derived organic contaminants requires further investigation. We characterised the influence of compost addition on water repellency in the laboratory by measuring the Water Drop Penetration Time (WDPT), sorptivity and water repellency index through infiltration experiments on soil samples amended with two composts made with contrasting feedstocks (green waste and predominantly meat waste). The treatments consisted of a sandy loam, a clay loam and a sandy loam contaminated with diesel fuel and aged for 3 years, which were amended with the two composts at a rate equivalent to 750t/ha. In addition core samples collected from a brownfield site, amended with compost at three different rates (250, 500 and 750t/ha) in 2007, were

  11. [Study on essential oils of medicinal plants in insect repellent].

    Science.gov (United States)

    Zhao, Hong-Zheng; Luo, Jiao-Yang; Liu, Qiu-Tao; Lv, Ze-Liang; Yang, Shi-Hai; Yang, Mei-Hua

    2016-01-01

    Mosquitoes are seriously harmful to human health for transmitting some mortal diseases. Among the methods of mosquito control, synthetical insecticides are the most popular. However, as a result of longterm use of these insecticides, high resistant mosquitos and heavy environmental pollution appear. Thus, eco-friendly prevention measures are taken into the agenda. Essential oils extracted from medicinal plants have repellent and smoked killing effects on mosquitoes. With abundant medical plants resources and low toxicity, they have the potential of being developed as a new type of mosquito and insect repellent agent. The recent application advances of essential oils of medicinal plants in insect repellent and its application limitations are overviewed. This review will provide references for the future development and in-depth study of essential oils. Copyright© by the Chinese Pharmaceutical Association.

  12. The Effects of Amofer Palm Oil Waste-based Complete Feed to Blood Profiles and Liver Function on Local Sheep

    Directory of Open Access Journals (Sweden)

    Hamdi Mayulu

    2012-04-01

    Full Text Available Amoniation-Fermentation (amofer technology should be conducted in order to improve the low quality of by product produced from palm oil plantations and mills (palm oil waste which is used for constituent of feed ingredients in complete feed (CF. This technology also reforms the feed material into edible form. Before broadly applicable, it must be ensured that the feed does not have toxic effects on livestock. This research was peformed to evaluate the effects of amofer palm oil waste-based CF to blood profile and liver function on local sheep. Completely Randomly Design (CRD was used with 4 treaments and 4 replications. The observed variables were the levels of hemoglobin, hematocrit, blood glucose, ALT and AST was analyzed by ANOVA. The average value of blood glucose levels at T1= 80.68 mg/dl, T2=79.08 mg/dl, T3=81.18 mg/dl and T4=73.70 mg/dl. The average value of hemoglobin levels at T1=10.80 g/dl, T2=10.30 g/dl, T3=11.23 g/dl and T4=10.25 g/dl. The average value of hematocrit levels at T1=31.00%, T2=31.00%, T3=33.75% and T4=30%. The average value of ALT levels at T1=17.90 ml, T2=13.83 ml, T3=18.75 ml and, T4=13.40 ml. The average value of AST level at T1=106.20 ml, T2=88.98 ml, T3=104.40 ml and T4=91.25 ml. There was no significant difference among four treatments (p>0.05. The administration CF did not cause hematological disorders which showed by the blood profiles and liver function were in normal range, so that suggested the CF was appropriate and safe for local sheep. [Keywords––amofer, complete feed, hemoglobin, hematocrit, glucose, liver function

  13. Evaluation of the repellent and insecticidal activities of the leaf, stem ...

    African Journals Online (AJOL)

    Adults of C. maculatus were exposed to grains treated separately with the root, stem and leaf powders of C. odorata at different exposure periods of 12, 24, 36, and 48 hours. All the three plant parts significantly repelled C. maculatus with the root powder showing the highest percentage repellency, although this was a ...

  14. Evaluation of the laboratory mouse model for screening topical mosquito repellents.

    Science.gov (United States)

    Rutledge, L C; Gupta, R K; Wirtz, R A; Buescher, M D

    1994-12-01

    Eight commercial repellents were tested against Aedes aegypti 0 and 4 h after application in serial dilution to volunteers and laboratory mice. Results were analyzed by multiple regression of percentage of biting (probit scale) on dose (logarithmic scale) and time. Empirical correction terms for conversion of values obtained in tests on mice to values expected in tests on human volunteers were calculated from data obtained on 4 repellents and evaluated with data obtained on 4 others. Corrected values from tests on mice did not differ significantly from values obtained in tests on volunteers. Test materials used in the study were dimethyl phthalate, butopyronoxyl, butoxy polypropylene glycol, MGK Repellent 11, deet, ethyl hexanediol, Citronyl, and dibutyl phthalate.

  15. Structural requirements for repellency: norsesquiterpenes and sesquiterpenoid derivatives of nootkatone against the Formosan subterranean termite (Isoptera: Rhinotermitidae).

    Science.gov (United States)

    Zhu, Betty C R; Henderson, Gregg; Sauer, Anne M; Crowe, William; Laine, Roger A

    2010-08-01

    Research has shown that the family of grapefruit flavors called nootkatones have significant repellant and toxic effects to Formosan subterranean termites (Coptotermes formosanus Shiraki). Nineteen synthetic nootkatone derivatives, along with three commercially available nootkatone derivatives, were tested for repellent activity against C. formosanus by a choice assay in a petri dish with a two-step triage procedure. Based on the repellency threshold value, the relationships between structure and activity are discussed. Four derivatives of nootkatone have very high repellency and toxicity to C. formosanus, 9 times the potency of the primary compound nootkatone. Four other compounds have between 2 and 3 times the repellency of nootkatones, and three compounds are equal in their repellency to nootkatone. Copyright (c) 2010 Society of Chemical Industry.

  16. (snail repellent paint) on land snails

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-19

    Oct 19, 2009 ... the above treatments has shown that repellent band and methaldehyde with 5 ± 1.3 and 10.6 ± 0.9 percentage ..... does not readily dissolve in water, which minimizes its dispersal ... limpets and macroalgae, J. Exp. Mar. Biol.

  17. Mosquito repellency of novel Trifluoromethylphenyl amides

    Science.gov (United States)

    Human diseases caused by mosquito-transmitted pathogens include malaria, dengue and yellow fever and are responsible for several million human deaths every year, according to the World Health Organization (WHO). Our current research projects focus on the development of new insecticides and repellent...

  18. Salivary Gland Proteome during Adult Development and after Blood Feeding of Female Anopheles dissidens Mosquitoes (Diptera: Culicidae).

    Science.gov (United States)

    Phattanawiboon, Benjarat; Jariyapan, Narissara; Mano, Chonlada; Roytrakul, Sittiruk; Paemanee, Atchara; Sor-Suwan, Sriwatapron; Sriwichai, Patchara; Saeung, Atiporn; Bates, Paul A

    Understanding changes in mosquito salivary proteins during the time that sporozoite maturation occurs and after blood feeding may give information regarding the roles of salivary proteins during the malarial transmission. Anopheles dissidens (formerly Anopheles barbirostris species A1) is a potential vector of Plasmodium vivax in Thailand. In this study, analyses of the proteomic profiles of female An. dissidens salivary glands during adult development and after blood feeding were carried out using two-dimensional gel electrophoresis coupled with nano-liquid chromatography-mass spectrometry. Results showed at least 17 major salivary gland proteins present from day one to day 21 post emergence at 8 different time points sampled. Although there was variation observed, the patterns of protein expression could be placed into one of four groups. Fifteen protein spots showed significant depletion after blood feeding with the percentages of the amount of depletion ranging from 8.5% to 68.11%. The overall results identified various proteins, including a putative mucin-like protein, an anti-platelet protein, a long form D7 salivary protein, a putative gVAG protein precursor, a D7-related 3.2 protein, gSG7 salivary proteins, and a gSG6 protein. These results allow better understanding of the changes of the salivary proteins during the adult mosquito development. They also provide candidate proteins to investigate any possible link or not between sporozoite maturation, or survival of skin stage sporozoites, and salivary proteins.

  19. Durability of two water repelents applied to granite

    Directory of Open Access Journals (Sweden)

    Rivas, T.

    1998-06-01

    Full Text Available The durability of two water-repellents for granitic stonework was determined. Weathered and sound samples of granites widely used in building construction and restoration in Galicia (NW Spain were treated with water repellents of known efficacy, and then subjected to two artificial weathering tests: prolonged exposure to UV light, and sodium sulphate crystallization cycles. In both tests, but especially in the salt crystallization cycles, both treatments rapidly lost their water-repellency. Furthermore, the hydrophobic layer of water repellent impeded salt mobility, favouring fissuration parallel to the treated surface, which was eventually shed in the form of a plaque.

    Se presentan los resultados de la durabilidad de dos tratamientos de hidrofugación aplicados a rocas graníticas ampliamente utilizados en la construcción de edificios en Galicia (Noroeste de España. Tras la evaluación de la eficacia de dichos tratamientos, cuyos resultados se presentaron en un trabajo anterior, se someten las muestras tratadas a dos ensayos diferentes de envejecimiento acelerado: ciclos de exposición a la luz ultravioleta y ciclos de cristalización de sulfato de sodio. Los productos hidrofugantes muestran una escasa resistencia a ambos ensayos, sobre todo a los ciclos de cristalización de sulfato de sodio; esta débil durabilidad se manifiesta en una rápida pérdida de sus propiedades hidrofugantes. Así mismo, se observa que la presencia de la capa hidrófoba en la piedra funciona como una barrera frente a la movilidad de sales, lo que ocasiona el total desprendimiento de aquella y un fuerte deterioro del material rocoso.

  20. Novel feed including bioactive compounds from winery wastes improved broilers' redox status in blood and tissues of vital organs.

    Science.gov (United States)

    Makri, Sotiria; Kafantaris, Ioannis; Stagos, Dimitrios; Chamokeridou, Theodora; Petrotos, Konstantinos; Gerasopoulos, Konstantinos; Mpesios, Anastasios; Goutzourelas, Nikolaos; Kokkas, Stylianos; Goulas, Panagiotis; Komiotis, Dimitrios; Kouretas, Dimitrios

    2017-04-01

    Currently, there is a great interest in the production of animal feed with antioxidant activity. The aim of this study was to examine the potential antioxidant effects of a feed supplemented with grape pomace (GP), a winery by-product with high environmental load, in chickens. Broilers of 15 days post birth were separated into two groups fed either with standard diet or with diet supplemented with GP for 35 days. Blood and tissues collections were performed after feeding for 15 and 35 days with the experimental diet (i.e. at 30 and 50 days post birth). Free radical toxicity markers, namely thiobarbituric acid reactive substances, protein carbonyls, total antioxidant capacity, reduced glutathione, catalase activity and rate of H 2 O 2 decomposition were determined in blood and tissues of vital organs. The results indicated that feed supplemented with GP decreased oxidative stress-induced toxic effects and improved chickens' redox status, and so it may also improve their wellness and productivity. On the other hand, this exploitation of GP may solve problems of environmental pollution in areas with wineries. Copyright © 2017. Published by Elsevier Ltd.

  1. A low-cost repellent for malaria vectors in the Americas: results of two field trials in Guatemala and Peru.

    Science.gov (United States)

    Moore, Sarah J; Darling, Samuel T; Sihuincha, Moisés; Padilla, Norma; Devine, Gregor J

    2007-08-01

    The cost of mosquito repellents in Latin America has discouraged their wider use among the poor. To address this problem, a low-cost repellent was developed that reduces the level of expensive repellent actives by combining them with inexpensive fixatives that appear to slow repellent evaporation. The chosen actives were a mixture of para-menthane-diol (PMD) and lemongrass oil (LG). To test the efficacy of the repellent, field trials were staged in Guatemala and Peru. Repellent efficacy was determined by human-landing catches on volunteers who wore the experimental repellents, control, or 15% DEET. The studies were conducted using a balanced Latin Square design with volunteers, treatments, and locations rotated each night. In Guatemala, collections were performed for two hours, commencing three hours after repellent application. The repellent provided >98% protection for five hours after application, with a biting pressure of >100 landings per person/hour. The 15% DEET control provided lower protection at 92% (p 46 landings per person/hour. The 20% DEET control provided significantly lower protection at 64% (p < 0.0001). In both locations, the PMD/LG repellent provided excellent protection up to six hours after application against a wide range of disease vectors including Anopheles darlingi. The addition of fixatives to the repellent extended its longevity while enhancing efficacy and significantly reducing its cost to malaria-endemic communities.

  2. A low-cost repellent for malaria vectors in the Americas: results of two field trials in Guatemala and Peru

    Directory of Open Access Journals (Sweden)

    Sihuincha Moisés

    2007-08-01

    Full Text Available Abstract Background The cost of mosquito repellents in Latin America has discouraged their wider use among the poor. To address this problem, a low-cost repellent was developed that reduces the level of expensive repellent actives by combining them with inexpensive fixatives that appear to slow repellent evaporation. The chosen actives were a mixture of para-menthane-diol (PMD and lemongrass oil (LG. Methods To test the efficacy of the repellent, field trials were staged in Guatemala and Peru. Repellent efficacy was determined by human-landing catches on volunteers who wore the experimental repellents, control, or 15% DEET. The studies were conducted using a balanced Latin Square design with volunteers, treatments, and locations rotated each night. Results In Guatemala, collections were performed for two hours, commencing three hours after repellent application. The repellent provided >98% protection for five hours after application, with a biting pressure of >100 landings per person/hour. The 15% DEET control provided lower protection at 92% (p 46 landings per person/hour. The 20% DEET control provided significantly lower protection at 64% (p Conclusion In both locations, the PMD/LG repellent provided excellent protection up to six hours after application against a wide range of disease vectors including Anopheles darlingi. The addition of fixatives to the repellent extended its longevity while enhancing efficacy and significantly reducing its cost to malaria-endemic communities.

  3. Insect repellents and sunscreen: implications for personal protection strategies against mosquito-borne disease.

    Science.gov (United States)

    Webb, Cameron E; Russell, Richard C

    2009-10-01

    To determine the protection times provided by insect repellent and sunscreen in combined formulations against biting mosquitoes. To determine if concurrent use of repellent and sunscreen influenced protection times. Insect repellent containing comparable concentrations of N, N-diethyl-3-methylbenzamide (DEET) with and without sunscreen were tested on human skin to determine the mean protection time (MPT) against Aedes aegypti (L.) in the laboratory. Further trials were undertaken to determine the effect on MPT of sunscreen reapplication over repellent every two hours. There was no significant difference in the MPT provided by 80% DEET with (MPT+/-SE=770+/-54.8 minutes) and without (MPT+/-SE=830+/-20.2 minutes) sunscreen or 7.14% DEET with (MPT+/-SE =240+/-15.5 minutes) and 6.98% DEET without (MPT+/-SE =230+/-18.4 minutes) sunscreen. Reapplication of sunscreen resulted in a significantly lower MPT of a 17.0% DEET formulation when sunscreen was reapplied concurrently (MPT+/-SE=330+/-25.2 minutes), compared with DEET alone (MPT+/-SE =400+/-12.7 minutes). When combined in a single formulation with sunscreen, the MPT provided by both high and low concentrations of DEET is not reduced. However, if sunscreen is reapplied over insect repellent, protection times can be reduced significantly. In areas of endemic mosquito-borne disease, the reapplication of a low concentration repellent and sunscreen formulation may provide the most effective protection from biting mosquitoes while minimising the risk of overexposure to DEET.

  4. An experimental hut study to quantify the effect of DDT and airborne pyrethroids on entomological parameters of malaria transmission

    Science.gov (United States)

    2014-01-01

    Background Current malaria vector control programmes rely on insecticides with rapid contact toxicity. However, spatial repellents can also be applied to reduce man-vector contact, which might ultimately impact malaria transmission. The aim of this study was to quantify effects of airborne pyrethroids from coils and DDT used an indoor residual spray (IRS) on entomological parameters that influence malaria transmission. Methods The effect of Transfluthrin and Metofluthrin coils compared to DDT on house entry, exit and indoor feeding behaviour of Anopheles gambiae sensu lato were measured in experimental huts in the field and in the semi-field. Outcomes were deterrence - reduction in house entry of mosquitoes; irritancy or excito-repellency – induced premature exit of mosquitoes; blood feeding inhibition and effect on mosquito fecundity. Results Transfluthrin coils, Metofluthrin coils and DDT reduced human vector contact through deterrence by 38%, 30% and 8%, respectively and induced half of the mosquitoes to leave huts before feeding (56%, 55% and 48%, respectively). Almost all mosquitoes inside huts with Metofluthrin and Transfluthrin coils and more than three quarters of mosquitoes in the DDT hut did not feed, almost none laid eggs and 67%, 72% and 70% of all mosquitoes collected from Transfluthrin, Metofluthrin and DDT huts, respectively had died after 24 hours. Conclusion This study highlights that airborne pyrethroids and DDT affect a range of anopheline mosquito behaviours that are important parameters in malaria transmission, namely deterrence, irritancy/excito-repellency and blood-feeding inhibition. These effects are in addition to significant toxicity and reduced mosquito fecundity that affect mosquito densities and, therefore, provide community protection against diseases for both users and non-users. Airborne insecticides and freshly applied DDT had similar effects on deterrence, irritancy and feeding inhibition. Therefore, it is suggested that

  5. An experimental hut study to quantify the effect of DDT and airborne pyrethroids on entomological parameters of malaria transmission.

    Science.gov (United States)

    Ogoma, Sheila B; Lorenz, Lena M; Ngonyani, Hassan; Sangusangu, Robert; Kitumbukile, Mohammed; Kilalangongono, Masoudi; Simfukwe, Emmanuel T; Mseka, Anton; Mbeyela, Edgar; Roman, Deogratius; Moore, Jason; Kreppel, Katharina; Maia, Marta F; Moore, Sarah J

    2014-04-01

    Current malaria vector control programmes rely on insecticides with rapid contact toxicity. However, spatial repellents can also be applied to reduce man-vector contact, which might ultimately impact malaria transmission. The aim of this study was to quantify effects of airborne pyrethroids from coils and DDT used an indoor residual spray (IRS) on entomological parameters that influence malaria transmission. The effect of Transfluthrin and Metofluthrin coils compared to DDT on house entry, exit and indoor feeding behaviour of Anopheles gambiae sensu lato were measured in experimental huts in the field and in the semi-field. Outcomes were deterrence--reduction in house entry of mosquitoes; irritancy or excito-repellency--induced premature exit of mosquitoes; blood feeding inhibition and effect on mosquito fecundity. Transfluthrin coils, Metofluthrin coils and DDT reduced human vector contact through deterrence by 38%, 30% and 8%, respectively and induced half of the mosquitoes to leave huts before feeding (56%, 55% and 48%, respectively). Almost all mosquitoes inside huts with Metofluthrin and Transfluthrin coils and more than three quarters of mosquitoes in the DDT hut did not feed, almost none laid eggs and 67%, 72% and 70% of all mosquitoes collected from Transfluthrin, Metofluthrin and DDT huts, respectively had died after 24 hours. This study highlights that airborne pyrethroids and DDT affect a range of anopheline mosquito behaviours that are important parameters in malaria transmission, namely deterrence, irritancy/excito-repellency and blood-feeding inhibition. These effects are in addition to significant toxicity and reduced mosquito fecundity that affect mosquito densities and, therefore, provide community protection against diseases for both users and non-users. Airborne insecticides and freshly applied DDT had similar effects on deterrence, irritancy and feeding inhibition. Therefore, it is suggested that airborne pyrethroids, if delivered in suitable

  6. Wolbachia Infection Reduces Blood-Feeding Success in the Dengue Fever Mosquito, Aedes aegypti

    OpenAIRE

    Turley, Andrew P.; Moreira, Luciano A.; O'Neill, Scott L.; McGraw, Elizabeth A.

    2009-01-01

    BACKGROUND: The mosquito Aedes aegypti was recently transinfected with a life-shortening strain of the endosymbiont Wolbachia pipientis (wMelPop) as the first step in developing a biocontrol strategy for dengue virus transmission. In addition to life-shortening, the wMelPop-infected mosquitoes also exhibit increased daytime activity and metabolic rates. Here we sought to quantify the blood-feeding behaviour of Wolbachia-infected females as an indicator of any virulence or energetic drain asso...

  7. Biologically inspired hairy surfaces for liquid repellency

    Science.gov (United States)

    Hsu, Shu-Hau

    Owing to remarkable features, such as self-cleaning, anti-biofouling and drag reduction, interest on rendering surfaces water-repellent has significantly grown within this decade. Attempts on making surfaces "superhydrophobic", where high water contact angle (θc >150°) accompanied with only few degrees of roll-off angle, have been extensively demonstrated through the mimicking of the surface chemistry and morphology of lotus leaves. This appealing phenomenon also exists on another structure from nature: surfaces comprising soft hairs. Although the role of this piliferous integument has long been recognized for providing life, arthropods in particular, waterrepellency, the synthetic superhydrophobic surfaces based on this structure are still very limited. In this study, the goal was to develop a novel liquid-repellent surface by mimicking the hairy exterior of species. The artificial hairy surfaces were prepared by means of pressurized membrane casting, in which thermoplastic sheets were forced to flow into porous membranes at elevated temperature. The G-shaped pillars on the membrane cast polypropylene substrate are particularly similar to the conformation of natural hairs. The principle of this fabrication technique is relatively accessible and is expected to be compatible with large-area fabrication of superhydrophobic interfaces. The artificial hairy surface features perfectly hydrophobic response where no contact angle hysteresis was observed from video assessment. Thus the artificial hairy surface of the current work appears to be the first report to have such extreme hydrophobicity with only structural modification from the original substrate. This ultralow adhesion to water droplet is believed to be attributed to the hydrophobic methyl groups and the mechanical response of the artificial hairs. Liquid repellency of the hairy surfaces was further enhanced by coating with fluorocarbon (CF) layers via deep reactive ion etching (DRIE). The contact angle of

  8. Status and Prospect of Test Methods of Quality Silicone Water Repellent for Protecting Reinforced Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Sun, H. Y.; Yuan, Z. Y.; Yang, Z.; Shan, G. L. [Nanjing Hydraulic Research Institute, Nanjing (China); Shen, M. X. [Hehai University, Nanjing (China)

    2017-06-15

    Impregnating with quality silicone water repellent on the concrete surface is an effective method of protecting concrete. Quality silicone water repellent has been widely used in the engineering profession because of its desirable properties such as hydrophobicity, keeping concrete breathable and preserving the original appearance of the concrete. The companies in China that produce silicone water repellent are listed. Test methods in the specifications or standards about silicone water repellent in China are summed. The test methods relative to durability of concrete impregnated with silicone water repellent (such as resistant to chloride ion penetration, resistant to alkali, resistance to freezing and thawing and weather ability etc.) and the constructive quality (such as water absorption rate, impregnating depth and the dry velocity coefficient etc.) are compared and analyzed. The results indicate that there are differences among test methods relative to different specifications with the same index and therefore, confusion has ensued when selecting test methods. All test methods with the exception of the method of water absorption rate by using a Karsten flask are not non-destructive methods or conducted in a laboratory. Finally, further research on silicone water repellent during application is proposed.

  9. Status and Prospect of Test Methods of Quality Silicone Water Repellent for Protecting Reinforced Concrete

    International Nuclear Information System (INIS)

    Sun, H. Y.; Yuan, Z. Y.; Yang, Z.; Shan, G. L.; Shen, M. X.

    2017-01-01

    Impregnating with quality silicone water repellent on the concrete surface is an effective method of protecting concrete. Quality silicone water repellent has been widely used in the engineering profession because of its desirable properties such as hydrophobicity, keeping concrete breathable and preserving the original appearance of the concrete. The companies in China that produce silicone water repellent are listed. Test methods in the specifications or standards about silicone water repellent in China are summed. The test methods relative to durability of concrete impregnated with silicone water repellent (such as resistant to chloride ion penetration, resistant to alkali, resistance to freezing and thawing and weather ability etc.) and the constructive quality (such as water absorption rate, impregnating depth and the dry velocity coefficient etc.) are compared and analyzed. The results indicate that there are differences among test methods relative to different specifications with the same index and therefore, confusion has ensued when selecting test methods. All test methods with the exception of the method of water absorption rate by using a Karsten flask are not non-destructive methods or conducted in a laboratory. Finally, further research on silicone water repellent during application is proposed.

  10. Laboratory and semi-field evaluations of two (Transfluthrin) spatial repellent devices against Aedes aegypti (L.) (Diptera: Culicidae)

    Science.gov (United States)

    Two transfluthrin-based spatial repellent products (Raid Dual Action Insect Repellent and Home Freshener and Raid Shield (currently not commercially available), SC Johnson, Racine WI) were evaluated for spatial repellent effects against female Aedes aegypti (L.) mosquitoes underlaboratory (wind tunn...

  11. Higher glandular trichome density in tomato leaflets and repellence to spider mites Alta densidade de tricomas glandulares em tomateiro e aumento da repelência a ácaros rajados

    Directory of Open Access Journals (Sweden)

    Wilson Roberto Maluf

    2007-09-01

    Full Text Available The objective of this work was to evaluate the feasibility of selection for higher glandular trichome densities, as an indirect criterion of selection for increasing repellence to spider mites Tetranychus urticae, in tomato populations derived from an interspecific cross between Lycopersicon esculentum x L. hirsutum var. glabratum PI 134417. Trichome densities were evaluated in 19 genotypes, including 12 from advanced backcross populations, derived from the original cross L. esculentum x L. hirsutum var. glabratum PI 134417. Counts were made both on the adaxial and abaxial leaf surfaces, and trichomes were classified into glandular types IV and VI, other glandular types (types I+VII, and nonglandular types. Mite repellence was measured by distances walked by mites onto the tomato leaf surface after 20, 40 and 60 min. Spider mite repellence biotests indicated that higher densities of glandular trichomes (especially type VI decreased the distances walked by the mites onto the tomato leaf surface. Selection of plants with higher densities of glandular trichomes can be an efficient criterion to obtain tomato genotypes with higher resistance (repellence to spider mites.O objetivo deste trabalho foi avaliar a eficiência da seleção para maior densidade de tricomas glandulares na resistência (repelência ao ácaro Tetranychus urticae, em populações de tomate derivadas do cruzamento interespecífico Lycopersicon esculentum x L. hirsutum var. glabratum PI 134417. Foram avaliados 19 genótipos quanto à densidade de tricomas, que incluíram 12 derivados de populações avançadas de retrocruzamentos, obtidos a partir do cruzamento original L. esculentum x L. hirsutum var. glabratum PI 134417. Nas faces abaxial e adaxial dos folíolos, realizaram-se as contagens e os tricomas foram classificados em glandulares tipo IV e VI, outros glandulares (tipo I e VII e não glandulares. A repelência aos ácaros foi medida pela distância média, percorrida pelo

  12. Bioassay-guided investigation of two Monarda essential oils as repellents of yellow fever mosquito Aedes aegypti.

    Science.gov (United States)

    Tabanca, Nurhayat; Bernier, Ulrich R; Ali, Abbas; Wang, Mei; Demirci, Betul; Blythe, Eugene K; Khan, Shabana I; Baser, K Husnu Can; Khan, Ikhlas A

    2013-09-11

    As part of an ongoing research program to identify active mosquito repellents, Monarda bradburiana Beck and Monarda fistulosa L. essential oils showed good repellent activity with minimum effective dosages (MED) of 0.055 ± 0.036 and 0.078 ± 0.027 mg/cm(2), respectively, compared to reference standard N,N-diethyl-3-methylbenzamide (DEET) (0.039 ± 0.014 mg/cm(2)). Systematic bioassay-guided fractionation of essential oils of both Monarda species was performed to identify the active repellent compounds, and isolated pure compounds were individually tested for repellency. Of the isolated compounds, carvacrol, thymol, eugenol, and carvacrol methyl ether were found to be the repellent compounds with MEDs in the range of 0.013-0.063 mg/cm(2). Active repellent compounds were also tested for larvicidal activity against 1-day-old Aedes aegypti larvae. Thymol was the best larvicide among the tested individual compounds (LD50 of 13.9 ppm). None of the individual compounds showed cytotoxicity against mammalian cells; however, the essential oils were toxic to all cell lines.

  13. Higher glandular trichome density in tomato leaflets and repellence to spider mites

    International Nuclear Information System (INIS)

    Maluf, Wilson Roberto; Inoue, Irene Fumi; Ferreira, Raphael de Paula Duarte; Gomes, Luiz Antonio Augusto; Castro, Evaristo Mauro de; Cardoso, Maria das Gracas

    2007-01-01

    The objective of this work was to evaluate the feasibility of selection for higher glandular trichome densities, as an indirect criterion of selection for increasing repellence to spider mites Tetranychus urticae, in tomato populations derived from an interspecific cross between Lycopersicon esculentum x L. hirsutum var. glabratum PI 134417. Trichome densities were evaluated in 19 genotypes, including 12 from advanced backcross populations, derived from the original cross L. esculentum x L. hirsutum var. glabratum PI 134417. Counts were made both on the adaxial and abaxial leaf surfaces, and trichomes were classified into glandular types IV and VI, other glandular types (types I+VII), and nonglandular types. Mite repellence was measured by distances walked by mites onto the tomato leaf surface after 20, 40 and 60 min. Spider mite repellence biotests indicated that higher densities of glandular trichomes (especially type VI) decreased the distances walked by the mites onto the tomato leaf surface. Selection of plants with higher densities of glandular trichomes can be an efficient criterion to obtain tomato genotypes with higher resistance (repellence) to spider mites. (author)

  14. Use of repellents formulated in Specialized Pheromone and Lure Application Technology (SPLAT®) for effective insect pest management

    Science.gov (United States)

    Agenor Mafra-Neto; Christopher J. Fettig; A. Steven Munson; Lukasz L. Stelinski

    2014-01-01

    Despite the many impediments to commercialization of insect repellents in agriculture and forestry, there are some situations where the use of repellents is desirable and warranted. ISCA Technologies (Riverside, California), together with collaborators from academic, government, and private sectors, is actively developing repellent formulations against several...

  15. Rhanterium epapposum Oliv. essential oil: Chemical composition and antimicrobial,insect-repellent and anticholinesterase activities

    Science.gov (United States)

    Essential oils from Rhanterium epapposum Oliv. (Asteraceae) was investigated for its repellent, antimicrobial and acetyl- and butyrylcholine esterase inhibitory activities. The oil showed good repellent activity while oils demonstrated weak in antimicrobial and cholinesterase inhibitions. Terpenoids...

  16. Improvement of Water Movement in an Undulating Sandy Soil Prone to Water Repellency

    NARCIS (Netherlands)

    Oostindie, K.; Dekker, L.W.; Wesseling, J.G.; Ritsema, C.J.

    2011-01-01

    The temporal dynamics of water repellency in soils strongly influence water flow. We investigated the variability of soil water content in a slight slope on a sandy fairway exhibiting water-repellent behavior. A time domain reflectometry (TDR) array of 60 probes measured water contents at 3-h

  17. Nutrient utilisation, growth performance and blood metabolites in Murrah buffalo calves (Bubalus bubalis) divergently selected for residual feed intake.

    Science.gov (United States)

    Sharma, Vijay K; Kundu, Shivlal S; Prusty, Sonali; Datt, Chander; Kumar, Muneendra

    2016-12-01

    The aim of this study was to evaluate differences in efficiency of feed utilisation between buffalo calves with low and high residual feed intake (RFI) by comparing feed intake, nutrient digestibility, growth traits and blood metabolites. Eighteen male Murrah buffalo calves (aged 4-6 months; 70 ± 1.0 kg body weight) were fed ad libitum with a total mixed ration for 120 d. Based on linear regression models involving dry matter intake (DMI), average daily gain (ADG) and mid-test metabolic body size, calves were assigned into low and high RFI groups. The RFI varied from -0.33 to +0.28 kg DM/d with an average RFI of -0.14 and 0.14 kg DM/d in low and high RFI calves, respectively. Calves had a mean DMI of 1.9 and 2.4 kg/d and an ADG of 0.5 and 0.6 kg/d in low and high RFI groups, respectively. Low RFI calves ate 19.0% less DM each day and required significantly less metabolisable energy for maintenance compared with high RFI calves (12.5 vs. 16.7 MJ/d). Nutrient digestibility and nitrogen balance did not differ among low and high RFI calves. In more efficient animals (low RFI calves) higher (p calves are more efficient in feed utilisation and the differences in blood metabolites are probably due to differences in feed intake and body metabolism.

  18. Association of different types of milk feeding with blood culture positive neonatal sepsis

    International Nuclear Information System (INIS)

    Anwar, M.; Waheed, K.A.I.; Rehman, A.

    2014-01-01

    To ascertain and compare microbial growth pattern in blood culture of septic neonates who were either totally breast or formula fed. Study Design: Cross sectional study. Place and Duration of Study: The Children's Hospital Lahore, Pakistan from Feb 2012 to Dec 2012. Methodology: All clinically septic neonates, who were either exclusively breast fed or formula fed, were enrolled in the study. They were divided into two groups and studied for the type of organisms grown on blood culture. Group-A were breast fed and group-B were formula fed. Neonates who were blood culture negative or had growth of multiple organisms or had incomplete data or who died / left against medical advice before completing the required data or babies receiving milk feeding from multiple sources or no feeding at all were excluded. BACTEC technique was used for obtaining bacterial growth. SPSS version 19 was used for statistical analysis. Results: A total of 380 clinically septic neonates were enrolled. Each group consisted of 190 subjects. Incidence of culture positive sepsis in breast fed and in formula fed was 6.7% and 15.7% respectively (p-value = 0.0001). Overall, gram-negative organisms constituted the majority (16.1%). Thirty seven percent cultures grew coagulase negative Staphylococcus (CoNS) followed by Klebsiella spp (23.4%). In group A, gram-negative and gram-positive organisms were equally distributed whilst in group-B, gram-negative organisms were three times more frequent than gram-positive organisms. Predominant pattern of organisms was also different in the two groups. In group-A, CoNS was predominant while in group-B, Klebsiella spp. was most frequent. Conclusion: Culture positive sepsis is more than two times greater in formula fed babies and is caused predominantly by gram-negative organisms whilst in breast fed babies, CoNS is the commonest organism. (author)

  19. Wetting properties of fungi mycelium alter soil infiltration and soil water repellency in a γ-sterilized wettable and repellent soil.

    Science.gov (United States)

    Chau, Henry Wai; Goh, Yit Kheng; Vujanovic, Vladimir; Si, Bing Cheng

    2012-12-01

    Soil water repellency (SWR) has a drastic impact on soil quality resulting in reduced infiltration, increased runoff, increased leaching, reduced plant growth, and increased soil erosion. One of the causes of SWR is hydrophobic fungal structures and exudates that change the soil-water relationship. The objective of this study was to determine whether SWR and infiltration could be manipulated through inoculation with fungi. The effect of fungi on SWR was investigated through inoculation of three fungal strains (hydrophilic -Fusarium proliferatum, chrono-amphiphilic -Trichoderma harzianum, and hydrophobic -Alternaria sp.) on a water repellent soil (WR-soil) and a wettable soil (W-soil). The change in SWR and infiltration was assessed by the water repellency index and cumulative infiltration respectively. F. proliferatum decreased the SWR on WR-soil and slightly increased SWR in W-soil, while Alternaria sp. increased SWR in both the W-soil and the WR-soil. Conversely T. harzianum increased the SWR in the W-soil and decreased the SWR in the WR-soil. All strains showed a decrease in infiltration in W-soil, while only the F. proliferatum and T. harzianum strain showed improvement in infiltration in the WR-soil. The ability of fungi to alter the SWR and enmesh soil particles results in changes to the infiltration dynamics in soil. Copyright © 2012 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  20. Effect of pectin, lecithin, and antacid feed supplements (Egusin®) on gastric ulcer scores, gastric fluid pH and blood gas values in horses

    Science.gov (United States)

    2014-01-01

    Background The objectives of this study were to evaluate the effects of two commercial feed supplements, Egusin 250® [E-250] and Egusin SLH® [E-SLH], on gastric ulcer scores, gastric fluid pH, and blood gas values in stall-confined horses undergoing feed-deprivation. Methods Nine Thoroughbred horses were used in a three-period crossover study. For the three treatment groups, sweet feed was mixed with E-250, E-SLH, or nothing (control group) and fed twice daily. Horses were treated for 21 days, then an additional 7 days while on an alternating feed-deprivation model to induce or worsen ulcers (period one). In periods two and three, horses (n=6) were treated for an additional 7 days after feed-deprivation. Gastroscopies were performed on day -1 (n=9), day 21 (n=9), day 28 (n=9) and day 35 (n=6). Gastric juice pH was measured and gastric ulcer scores were assigned. Venous blood gas values were also measured. Results Gastric ulcers in control horses significantly decreased after 21 days, but there was no difference in ulcer scores when compared to the Egusin® treated horses. NG gastric ulcer scores significantly increased in E-250 and control horses on day 28 compared to day 21 as a result of intermittent feed-deprivation, but no treatment effect was observed. NG ulcer scores remained high in the control group but significantly decreased in the E-SLH- and E-250-treated horses by day 35. Gastric juice pH values were low and variable and no treatment effect was observed. Mean blood pCO2 values were significantly increased two hours after feeding in treated horses compared to controls, whereas mean blood TCO2 values increased in the 24 hour sample, but did not exceed 38 mmol/l. Conclusions The feed-deprivation model increased NG gastric ulcer severity in the horses. However, by day 35, Egusin® treated horses had less severe NG gastric ulcers compared to untreated control horses. After 35 days, Egusin® products tested here ameliorate the severity of gastric ulcers in

  1. Angelica sinensis (Umbelliferae) with proven repellent properties against Aedes aegypti, the primary dengue fever vector in Thailand.

    Science.gov (United States)

    Champakaew, D; Junkum, A; Chaithong, U; Jitpakdi, A; Riyong, D; Sanghong, R; Intirach, J; Muangmoon, R; Chansang, A; Tuetun, B; Pitasawat, B

    2015-06-01

    Botanical resources with great diversity in medicinal and aromatic plants are a rich and reliable source for finding insect repellents of plant origin, which are widely popular among today's consumers. Although some herbal-based repellents have been proven comparable to or even better than synthetics, commercially available natural repellents generally tend to be expensive, with short-lived effectiveness. This critical flaw leads to ongoing research for new and effective repellents, which provide longer protection against vector and nuisance-biting insects, while remaining safe, user friendly, and reasonably priced. This study aimed to evaluate the repellent activity of plant-derived products against the primary dengue vector, Aedes aegypti, by following the human bait technique of World Health Organization guidelines. Preliminary laboratory screening tests for repellency of 33 plant species clearly demonstrated Angelica sinensis as the most effective repellent from each kind of extracted product, with its essential oil and ethanolic extract having median complete protection times of 7.0 h (6.0-7.5) and 2.5 h (2.0-2.5), respectively. Due to its low yield (0.02 %), pungent smell, and little cause of irritation, A. sinensis essential oil did not qualify as a candidate for further repellent assessment. However, subsequent extractions of A. sinensis with different organic solvents of increasing polarity provided four extractants with varying degrees of repellency against A. aegypti. The hexane extract of A. sinensis provided excellent repellency, with a median complete protection time of 7.5 h (6.5-8.5), which was longer than that of ethanol (2.5, 2.0-2.5 h), acetone (1.75, 0.5-2.5 h), and methanol extracts (0.5, 0-1.0 h). By being the most effective product, A. sinensis hexane extract gave significant protection comparable to that of its essential oil and the standard synthetic repellent, N,N-diethyl-3-methylbenzamide (DEET: 6.25, 5.0-6.5 h). Qualitative gas

  2. Analysing the Repellents Using EDXRF Method

    International Nuclear Information System (INIS)

    Khin Mi Mi; Khin Yi; Sein Htoon

    2004-05-01

    Determination of elemental contents in neem oil was evaluated using EDXRF.The comparsion on elemental concentrations of mosquito repellents cream, lotion and neem oil had been made. Where the neem oil was applied to the exposed body, it was found that the neem oil gives the protection action from the bites of mosquitoes

  3. New procedure for sampling infiltration to assess post-fire soil water repellency

    Science.gov (United States)

    P. R. Robichaud; S. A. Lewis; L. E. Ashmun

    2008-01-01

    The Mini-disk Infiltrometer has been adapted for use as a field test of post-fire infiltration and soil water repellency. Although the Water Drop Penetration Time (WDPT) test is the common field test for soil water repellency, the Mini-disk Infiltrometer (MDI) test takes less time, is less subjective, and provides a relative infiltration rate. For each test, the porous...

  4. Bio-inspired water repellent surfaces produced by ultrafast laser structuring of silicon

    International Nuclear Information System (INIS)

    Barberoglou, M.; Zorba, V.; Stratakis, E.; Spanakis, E.; Tzanetakis, P.; Anastasiadis, S.H.; Fotakis, C.

    2009-01-01

    We report here an efficient method for preparing stable superhydrophobic and highly water repellent surfaces by irradiating silicon wafers with femtosecond laser pulses and subsequently coating them with chloroalkylsilane monolayers. By varying the laser pulse fluence on the surface one can successfully control its wetting properties via a systematic and reproducible variation of roughness at micro- and nano-scale, which mimics the topology of natural superhydrophobic surfaces. The self-cleaning and water repellent properties of these artificial surfaces are investigated. It is found that the processed surfaces are among the most water repellent surfaces ever reported. These results may pave the way for the implementation of laser surface microstructuring techniques for the fabrication of superhydrophobic and self-cleaning surfaces in different kinds of materials as well

  5. Efficacy of plant-derived and synthetic compounds on clothing as repellents against Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae).

    Science.gov (United States)

    Jordan, Robert A; Schulze, Terry L; Dolan, Marc C

    2012-01-01

    We conducted field trials to compare the relative repellent activity of two natural product compounds (nootkatone and carvacrol) with commercially available plant-derived (EcoSMART organic insect repellent) and permethrin-based (Repel Permanone) repellents against adult Ixodes scapularis Say and Amblyomma americanum (L.) (Acari: Ixodidae) by using treated coveralls. One day after treatment, nootkatone and carvacrol provided 100% repellency of I. scapularis adults, with nootkatone maintaining complete protection through 3 d, whereas carvacrol showed steadily declining repellency against I. scapularis during the 7-d course of the trials. Nootkatone was at least as effective against host-seeking A. americanum as against I. scapularis through 3 d. Carvacrol provided little protection against A. americanum adults. Both natural compounds performed well initially in comparison with the commercial products. After 7 d, nootkatone was the most effective against both species followed in order of activity by Permanone, EcoSMART, and carvacrol. Nootkatone seems to have offer considerable potential as a clothing repellent against both I. scapularis and A. americanum.

  6. Water repellency, plants, agriculture abandonment and fire in citrus plantations. The Canyoles river watershed study site

    Science.gov (United States)

    Cerdà, Artemi; Jordán, Antonio; Doerr, Stefan Helmut

    2017-04-01

    Soil water repellency (SWR) is a key soil property that determine the soil and water losses, soil fertility and plant development. Although until the 90's the soil water repellency was seeing as an uncommon soil characteristic, now is considered a key soil property to understand the soil hydrology (Alanís et al., 2016; Hewelke et al., 2016; Keesstra et al., 2016; Jiménez-Morillo et al., 2016). The inspiring research of Leonard DeBano and Stefan H Doerr changed the fate of the science (DeBano, 2000; Doerr et al. 2000). Soil water repellency was associated to forest fire affected land due to the pioneer contribution of professor DeBano in the 70's and Professor Doerr in the 90's. The research during the last two decades demonstrate that fire affects the reallocation of the hydrophobic substances and can reduce or increase the severity of the soil water repellence at different soil depths and horizons. The SWR is usually measured by sampling to show the influence of key soil properties (texture, structure, plant cover, litter, season…) on the degree of soil water repellency. The sampling is applied usually with a few drops when the Water Drop Penetration Time method is applied, and this inform of the time of penetration, but few researches focussed in the spatial distribution of the water repellency, which is a key factor of the runoff generation, the water infiltration and the water redistribution such as demonstrate the wetting fronts. Our approach research the spatial distribution of the water repellency by means of an intense sampling of soil surface water repellency. One thousand drops were distributed in a square meter (100 lines separated 1 cm and 100 drops per each line of 100 cm, with a total od 1000 drops in 1m2) on 10 sampling points on 4 land managements: ploughing and herbicide agriculture fields treatment), abandoned 10 years, and burnt. The research was carried out in citrus plantations of the Canyoles river watershed. The results show that the

  7. Spatial repellency of metofluthrin-impregnated multilayer paper strip against Aedes albopictus under outdoor conditions, Nagasaki, Japan

    OpenAIRE

    Argueta, Tamara Belzabel Obispo; Kawada, Hitoshi; Takagi, Masahiro

    2004-01-01

    Spatial repellency of a new device in which metofluthrin, a newly synthesized pyrethroid, is impregnated into a multilayer paper strip, against Aedes albopictus was evaluated under outdoor conditions. High spatial repellency (>80%) with the metofluthrin-impregnated (200 mg) device lasted for more than 6 weeks, while the repellency with the same device impregnated with the same amount of transfluthrin declined within 5 weeks after treatment.

  8. Protection against mosquito vectors Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus using a novel insect repellent, ethyl anthranilate.

    Science.gov (United States)

    Islam, Johirul; Zaman, Kamaruz; Tyagi, Varun; Duarah, Sanjukta; Dhiman, Sunil; Chattopadhyay, Pronobesh

    2017-10-01

    Growing concern on the application of synthetic mosquito repellents in the recent years has instigated the identification and development of better alternatives to control different mosquito-borne diseases. In view of above, present investigation evaluates the repellent activity of ethyl anthranilate (EA), a non-toxic, FDA approved volatile food additive against three known mosquito vectors namely, Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus under laboratory conditions following standard protocols. Three concentration levels (2%, 5% and 10% w/v) of EA were tested against all the three selected mosquito species employing K & D module and arm-in-cage method to determine the effective dose (ED 50 ) and complete protection time (CPT), respectively. The repellent activity of EA was further investigated by modified arm-in-cage method to determine the protection over extended spatial ranges against all mosquito species. All behavioural situations were compared with the well-documented repellent N,N-diethylphenyl acetamide (DEPA) as a positive control. The findings demonstrated that EA exhibited significant repellent activity against all the three mosquitoes species. The ED 50 values of EA, against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus were found to be 0.96%, 5.4% and 3.6% w/v, respectively. At the concentration of 10% w/v, it provided CPTs of 60, 60 and 30min, respectively, against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus mosquitoes. Again in spatial repellency evaluation, EA was found to be extremely effective in repelling all the three tested species of mosquitoes. Ethyl anthranilate provided comparable results to standard repellent DEPA during the study. Results have concluded that the currently evaluated chemical, EA has potential repellent activity against some well established mosquito vectors. The study emphasizes that repellent activity of EA could be exploited for developing effective, eco

  9. Laboratory survival and blood feeding response of wild-caught Culicoides obsoletus Complex (Diptera: Ceratopogonidae) through natural and artificial membranes.

    Science.gov (United States)

    Goffredo, M; Romeo, G; Monaco, F; Di Gennaro, A; Savini, G

    2004-01-01

    In late summer 2002, live wild-caught midges of the Obsoletus Complex were collected using blacklight traps placed at a horse stable in Teramo (Abruzzo, Italy). For the survival study under laboratory conditions, 1,500 Obsoletus Complex midges were kept at 17 degrees C-25 degrees C and provided only with a sucrose solution. Of these, 150 (10%) survived for at least 40 days and 3 midges were still alive after 92 days. In addition, 10 midges survived 10 days at 4 degrees C. For the feeding trials, 40 blood-meals (9,440 midges) were administered, 27 of which were successful (67.5%); the feeding rate ranged from 0.3% to 16.7%, with a total of 592 engorged midges. Similar feeding rates (U Mann-Whitney test=129.5 p>0.05) were obtained when natural (day-old chicken skin) and artificial (stretched parafilm) membranes were used. To infect the insects, a field strain of bluetongue (BT) virus (BTV) serotype 2 isolated from the spleen of a sheep during the 2000 Italian outbreak was added to the blood-meal. Two different viral solutions, with titres of 10(6)TCID(50)/ml and 10(7)TCID(50)/ml, were prepared. Uninfected blood was significantly more appetising (U Mann-Whitney test=88.5 pdays. During the incubation period, the dead insects were collected daily and analysed for evidence of virus infection. Of the 251 engorged midges, 54 (21.5%) died in the feeding chambers or during sorting on the chill table, 136 died within the first 10 days and 61 survived longer. BTV was isolated only from those which died just after feeding (52.6%; 10/19) or 24 h later (47.8%; 11/23). Considering the small number of midges tested after 10 days of incubation, the prevalence of infection detected in this study (95% probability) would have been higher than 4.74%. These preliminary results appear very promising as this is the first time that midges of the Obsoletus Complex have been successfully fed under laboratory conditions.

  10. Identification of repellent odorants to the body louse, Pediculus humanus corporis, in clove essential oil.

    Science.gov (United States)

    Iwamatsu, Takuma; Miyamoto, Daisuke; Mitsuno, Hidefumi; Yoshioka, Yoshiaki; Fujii, Takeshi; Sakurai, Takeshi; Ishikawa, Yukio; Kanzaki, Ryohei

    2016-04-01

    The control of body lice is an important issue for human health and welfare because lice act as vectors of disease such as typhus, relapsing fever, and trench fever. Body lice exhibit avoidance behavior to some essential oils, including clove essential oil. Therefore, odorants containing clove essential oil components may potentially be useful in the development of repellents to body lice. However, such odorants that induce avoidance behavior in body lice have not yet been identified from clove essential oil. Here, we established an analysis method to evaluate the avoidance behavior of body lice to specific odorants. The behavioral analysis of the body lice in response to clove essential oil and its constituents revealed that eugenol, a major component of clove essential oil, has strong repellent effect on body lice, whereas the other components failed to induce obvious avoidance behavior. A comparison of the repellent effects of eugenol with those of other structurally related odorants revealed possible moieties that are important for the avoidance effects to body lice. The repellent effect of eugenol to body lice was enhanced by combining it with the other major component of clove essential oil, β-caryophyllene. We conclude that a synthetic blend of eugenol and β-caryophyllene is the most effective repellent to body lice. This finding will be valuable as the potential use of eugenol as body lice repellent.

  11. Spatial repellents on strips of camouflage netting reduce mosquito collections in a field environment

    Science.gov (United States)

    Barrier treatments can be effective in reducing host seeking mosquito vectors and provide an additional layer of passive defense, reducing disease risk. Devices designed to release spatial repellents or direct application of spatial repellents to artificial surfaces can serve as efficient barriers r...

  12. Spatial repellency screening in a high-throughput apparatus with Aedes aegypti and Anopheles gambiae

    Science.gov (United States)

    Spatial repellents are essential for personal protection against mosquitoes, such as Aedes aegypti and Anopheles gambiae, to reduce annoyance biting and transmission of mosquito-borne diseases. The number of safe and effective repellents, including DEET, picaridin, and IR3535, is limited and contin...

  13. Repellent Action of Carapa guianensis and Caesalpinia ferrea for flies species of Calliphoridae family

    Directory of Open Access Journals (Sweden)

    Ciciane Pereira Marten Fernandes

    2016-05-01

    Full Text Available ABSTRACT: Myiases occur by the infestation of fly larvae in tissues of live vertebrate animals, resulting in economic loss. Phytotherapy is considered an important alternative in the control of insects, which may reduce the economic impacts . Carapa guianensis is a plant that has been studied as a repellent against mosquitoes and Caesalpinia ferrea is reported in tropical climates, and there are few studies about its repellent action. The present study was designed to evaluate the repellent action of s C. guianensis and C. ferrea plants on flies species of the Calliphoridae family. W.O.T. traps containing deteriorated bovine liver and herbs cream of at concentrations of 20 and 50% were used to catch the flies. It was reported that the creams containing C. ferrea at concentrations of 20 and 50% and C. guianensis at the concentration of 50% have repellent effect against species of Calliphoridae family.

  14. Seasonal abundance and blood feeding activity of Anopheles minimus Theobald (Diptera: Culicidae) in Thailand.

    Science.gov (United States)

    Chareonviriyaphap, Theeraphap; Prabaripai, Atchariya; Bangs, Michael J; Aum-Aung, Boonserm

    2003-11-01

    Anopheline mosquito larvae and adults were sampled at Ban Pu Teuy, Tri-Yok District, Kanchanaburi Province, western Thailand, from January 2000 to December 2001. Over the period of 2 yr, Anopheles minimus sensu lato was the most commonly collected species, followed by Anopheles swadiwongporni and Anopheles dirus sensu lato; all three species are important vectors of malaria in Thailand. Attempted blood feeding by An. minimus occurred throughout the night, with two distinct feeding peaks: strong activity immediately after sunset (1800-2100 hours), followed by a second, less pronounced, rise before sunrise (0300-0600 hours). Anopheles minimus were more abundant during the wet season compared with the dry and hot seasons, although nocturnal adult feeding patterns were similar. Anopheles minimus fed readily on humans inside and outside of houses, showing a slight preference for exophagy. The human-biting peak of An. minimus in our study area differed from other localities sampled in Thailand, indicating the possible existence of site-specific populations of An. minimus exhibiting different host-seeking behavior. These results underscore the importance of conducting site-specific studies to accurately determine vector larval habitats and adult activity patterns and linking their importance in malaria transmission in a given area.

  15. Field Evaluations of Topical Arthropod Repellents in North, Central, and South America

    Science.gov (United States)

    2014-09-01

    De La Rocque et al. 2011) and their spread into higher elevations of Africa, Latin America , and Asia (Epstein 2001). Dengue fever and...denguehemorrhagic fever have resurgeddramatically in Latin America (Zell 2004). In North America ,West Nile virus has impacted signiÞcantly the health and welfare of...VECTOR CONTROL, PEST MANAGEMENT, RESISTANCE, REPELLENTS Field Evaluations of Topical Arthropod Repellents in North, Central , and South America KENDRA

  16. Effects of wildfire on soil water repellency in pine and eucalypt forest in central Portugal

    Science.gov (United States)

    Faria, Sílvia; Eufemia Varela, María.; Keizer, Jan Jacob

    2010-05-01

    Soil water repellency is a naturally occurring phenomenon that can be intensified by soil heating during fires. Fire-induced or -enhanced water repellency, together with the loss of plant cover, is widely regarded as a key factor in increased surface runoff and accelerated erosion in recently burnt areas. The present study is part of the EROSFIRE-II project, whose main aim is to assess and predict post-wildfire hydrological and erosion processes at multiple spatial scales, ranging from micro-plot (Pinus pinaster and Eucaliptus globulus). In addition, two similar but long unburned slopes were selected in the immediate surroundings. For a period of 10 months, starting November 2008, water repellency and moisture content of the 0-5 cm topsoil layer were measured in the field at monthly intervals. Repellency was measured using the ‘Molarity of an Ethanol Droplet' (MED) test, soil moisture content using a DECAGON EC5 sensor. The results revealed a very strong repellency (ethanol classes 6-7) at all four sites during the first sampling period in November 2008, suggesting that the immediate wildfire effects were minor for both forest types. In the subsequent 5 to 6 months, however, there was a definite tendency for higher ethanol classes at the recently burnt than the adjacent unburned sites. Especially in the case of the pine stands, this tendency was inverted during the remaining months. The above-mentioned differences between the neighboring sites reflected more pronounced temporal patters in the case of the unburned sites, where median repellency levels corresponded none to slight severity ratings from December to March (pine) or April (eucalypt). Such seasonal drops in repellency were considerably shorter at the two burnt sites (1-2 months) and also less pronounced, without median ethanol classes becoming zero as occurred at the burnt sites. The seasonal repellency patterns at the unburned sites could be explained rather well by changes in soil moisture content

  17. Temporal fluctuations in soil water repellency following wildfire in chaparral steeplands, southern California

    Science.gov (United States)

    K.R. Hubbert; V. Oriol

    2005-01-01

    Soil water repellency is partularly common in unburned chaparral, and its degree and duration can be influenced by seasonal weather conditions. Water repellency tends to increase in dry soils, whil eit decreases or vanishes following precipitation or extended periods of soil moisture. The 15426 ha Williams Fire provided an opportunity to investigate post-fire...

  18. Efficacy of topical permethrin as repellent against Aedes aegypti's bites.

    Science.gov (United States)

    Miot, Hélio Amante; Ferreira, Daniela Pinho; Mendes, Fabiana Guandalini; Carrenho, Flávia Roberta Hernandes; de Oliveira Amui, Isabela; Carneiro, Carlos Augusto Sá; Madeira, Newton Goulart

    2008-07-15

    Mosquitoes are the most important vectors of infectious diseases and their bites are related to several adverse skin reactions. Permethrin impregnated clothes are an efficient strategy against arthropods' bites; however, its topical efficacy as a repellent has not been well established. We studied the response to permethrin lotion 5 percent and N,N-Diethyl-meta-toluamide (DEET) spray 50 percent applied to the unprotected forearms of 10 volunteers. Each arm was exposed to 20 female mosquitoes of Aedes aegypti. We performed 71 bilateral comparative measurements evaluating the timing for the first bites. The average times for the arm without the product, with permethrin 5 percent, and with DEET 50 percent were: 7.9 seconds, 336.2 seconds and 7512.1 seconds. The results showed a significant difference between repellency times between either product and unprotected controls. In addition, there was a significant difference in time to first bite between permethrin and DEET treated arms (pAedes aegypti bites in this experimental setting. However, permethrin's profile of repellency was significantly inferior to that of DEET.

  19. Determining Exposure Factors of Anti-Fogging, Dye, Disinfectant, Repellent, and Preservative Products in Korea.

    Science.gov (United States)

    Lee, Daeyeop; Kim, Joo-Hyon; Kim, Taksoo; Yoon, Hyojung; Jo, Areum; Lee, Byeongwoo; Lim, Hyunwoo; Kim, Pilje; Seo, Jungkwan

    2018-01-30

    Reliable exposure factors are essential to determine health risks posed by chemicals in consumer products. We analyzed five risk-concerned product categories (anti-fogging, dye, disinfectant, repellent, and preservative products) for 13 products (three car anti-fogging products, a lens anti-fogging product, two car dye products, two drain disinfectants, an air conditioner disinfectant, a chlorine-based disinfectant, a fabric repellent, an insect repellent for food, and a wood preservative) considered to be of high risk in order to determine exposure factors via web surveys and estimation of amount of product. Among the 3000 participants (1482 (49%) men) aged ≥19 years, drain disinfectants were used most frequently (38.2%); the rate of usage of the other products ranged between 1.1-24.0%. The usage rates for the consumer products differed by sex, age, income, and education. Some consumer products such as car and lens anti-fogging products, chlorine-based disinfectants, fabric repellents, and drain disinfectants were regularly used more than once a month, while car dye products, air conditioner disinfectants, insect repellents for food, and wood preservatives were not regularly used owing to the specific product purposes and seasonal needs. Our results could be used for managing or controlling chemical substances in consumer products and conducting accurate exposure assessments.

  20. Synergistic mosquito-repellent activity of Curcuma longa, Pogostemon heyneanus and Zanthoxylum limonella essential oils.

    Science.gov (United States)

    Das, N G; Dhiman, Sunil; Talukdar, P K; Rabha, Bipul; Goswami, Diganta; Veer, Vijay

    2015-01-01

    Mosquito repellents play an important role in preventing man-mosquito contact. In the present study, we evaluated the synergistic mosquito-repellent activity of Curcuma longa, Pogostemon heyneanus and Zanthoxylum limonella essential oils. The mosquito repellent efficacies of three essential oils were evaluated separately and in combination under laboratory and field conditions. N,N-Diethylphenylacetamide (DEPA) and dimethylphthalate (DMP) were used for comparison of the protection time of the mixture of essential oils. At an optimum concentration of 20%, the essential oils of C. longa, Z. limonella and P. heyneanus provided complete protection times (CPTs) of 96.2, 91.4 and 123.4 min, respectively, against Aedes albopictus mosquitoes in the laboratory. The 1:1:2 mixture of the essential oils provided 329.4 and 391.0 min of CPT in the laboratory and field trials, respectively. The percent increases in CPTs for the essential oil mixture were 30 for DMP and 55 for N,N-diethylphenylacetamide (DEPA). The synergistic repellent activity of the essential oils used in the present study might be useful for developing safer alternatives to synthetic repellents for personal protection against mosquitoes. Copyright © 2015 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

  1. Blood-feeding patterns of Anopheles mosquitoes in a malaria-endemic area of Bangladesh

    Directory of Open Access Journals (Sweden)

    Bashar Kabirul

    2012-02-01

    Full Text Available Abstract Background Blood-feeding patterns of mosquitoes are crucial for incriminating malaria vectors. However, little information is available on the host preferences of Anopheles mosquitoes in Bangladesh. Therefore, the objective of the present study was to determine the hematophagic tendencies of the anophelines inhabiting a malaria-endemic area of Bangladesh. Methods Adult Anopheles mosquitoes were collected using light traps (LTs, pyrethrum spray (PS, and human bait (HB from a malaria-endemic village (Kumari, Bandarban, Bangladesh during the peak months of malaria transmission (August-September. Enzyme-linked immunosorbent assay (ELISA and polymerase chain reaction (PCR were performed to identify the host blood meals of Anopheles mosquitoes. Results In total, 2456 female anopheline mosquitoes representing 21 species were collected from the study area. Anopheles vagus Doenitz (35.71% was the dominant species followed by An. philippinensis Ludlow (26.67% and An. minimus s.l. Theobald (5.78%. All species were collected by LTs set indoors (n = 1094, 19 species were from outdoors (n = 784, whereas, six by PS (n = 549 and four species by HB (n = 29. Anopheline species composition significantly differed between every possible combination of the three collection methods (χ2 test, P Anopheles samples belonging to 17 species. Values of the human blood index (HBI of anophelines collected from indoors and outdoors were 6.96% and 11.73%, respectively. The highest values of HBI were found in An. baimai Baimaii (80%, followed by An. minimus s.l. (43.64% and An. annularis Van den Wulp (37.50%. Anopheles baimai (Bi = 0.63 and An. minimus s.l. (Bi = 0.24 showed strong relative preferences (Bi for humans among all hosts (human, bovine, goats/sheep, and others. Anopheles annularis, An. maculatus s.l. Theobald, and An. pallidus Theobald exhibited opportunistic blood-feeding behavior, in that they fed on either humans or animals, depending on whichever was

  2. Oleoresin Capsicum has Potential as a Rodent Repellent in Direct Sedding Longleaf Pine

    Science.gov (United States)

    James P. Barnett

    1998-01-01

    Direct seeding of southern pines has been a versatile and inexpensive alternative to planting on many reforestation sites across the South. Successful direct seeding has required that seeds be coated with thiram to repel birds, and with endrin to repel rodents. Endrin, which is extremely toxic, is no longer produced in the United States. Therefore, a substitute is...

  3. Infection history of the blood-meal host dictates pathogenic potential of the Lyme disease spirochete within the feeding tick vector.

    Directory of Open Access Journals (Sweden)

    Bharti Bhatia

    2018-04-01

    Full Text Available Lyme disease in humans is caused by several genospecies of the Borrelia burgdorferi sensu lato (s.l. complex of spirochetal bacteria, including B. burgdorferi, B. afzelii and B. garinii. These bacteria exist in nature as obligate parasites in an enzootic cycle between small vertebrate hosts and Ixodid tick vectors, with humans representing incidental hosts. During the natural enzootic cycle, infected ticks in endemic areas feed not only upon naïve hosts, but also upon seropositive infected hosts. In the current study, we considered this environmental parameter and assessed the impact of the immune status of the blood-meal host on the phenotype of the Lyme disease spirochete within the tick vector. We found that blood from a seropositive host profoundly attenuates the infectivity (>104 fold of homologous spirochetes within the tick vector without killing them. This dramatic neutralization of vector-borne spirochetes was not observed, however, when ticks and blood-meal hosts carried heterologous B. burgdorferi s.l. strains, or when mice lacking humoral immunity replaced wild-type mice as blood-meal hosts in similar experiments. Mechanistically, serum-mediated neutralization does not block induction of host-adapted OspC+ spirochetes during tick feeding, nor require tick midgut components. Significantly, this study demonstrates that strain-specific antibodies elicited by B. burgdorferi s.l. infection neutralize homologous bacteria within feeding ticks, before the Lyme disease spirochetes enter a host. The blood meal ingested from an infected host thereby prevents super-infection by homologous spirochetes, while facilitating transmission of heterologous B. burgdorferi s.l. strains. This finding suggests that Lyme disease spirochete diversity is stably maintained within endemic populations in local geographic regions through frequency-dependent selection of rare alleles of dominant polymorphic surface antigens.

  4. Insect Repellents and Associated Personal Protection for a Reduction in Human Disease

    Science.gov (United States)

    2012-01-01

    of topical repellents and scrub typhus was reduced through the use of treated clothing. Successful reduction of leishmaniasis was achieved through the...epidemic typhus , scrub typhus , plague and malaria. The result was the development of many of the modern strategies for vector control that we take for...prevent bites and disease. They gave examples that represented well-documented disease reduction achieved with repellent clothing ( scrub typhus ; McCulloch

  5. Quantifying the Effect of Soil Water Repellency on Infiltration Parameters Using a Dry Sand

    Science.gov (United States)

    Shillito, R.; Berli, M.; Ghezzehei, T. A.; Kaminski, E.

    2017-12-01

    Water infiltration into less than perfectly wettable soils has usually been considered an exceptional case—in fact, it may be the rule. Infiltration into soils exhibiting some degree of water repellency has important implications in agricultural irrigation, post-fire runoff, golf course and landscape management, and spill and contaminant mitigation. Beginning from fundamental principles, we developed a physically-based model to quantify the effect of water repellency on infiltration parameters. Experimentally, we used a dry silica sand and treated it to achieve various known degrees of water repellency. The model was verified using data gathered from multiple upward infiltration (wicking) experiments using the treated sand. The model also allowed us to explore the effect of initial soil moisture conditions on infiltration into water-repellent soils, and the physical interpretation of the simple water drop penetration time test. These results provide a fundamental step in the physically-based understanding of how water infiltrates into a less than perfectly wettable porous media.

  6. Peatland water repellency: Importance of soil water content, moss species, and burn severity

    Science.gov (United States)

    Moore, P. A.; Lukenbach, M. C.; Kettridge, N.; Petrone, R. M.; Devito, K. J.; Waddington, J. M.

    2017-11-01

    Wildfire is the largest disturbance affecting peatlands, with northern peat reserves expected to become more vulnerable to wildfire as climate change enhances the length and severity of the fire season. Recent research suggests that high water table positions after wildfire are critical to limit atmospheric carbon losses and enable the re-establishment of keystone peatland mosses (i.e. Sphagnum). Post-fire recovery of the moss surface in Sphagnum-feathermoss peatlands, however, has been shown to be limited where moss type and burn severity interact to result in a water repellent surface. While in situ measurements of moss water repellency in peatlands have been shown to be greater for feathermoss in both a burned and unburned state in comparison to Sphagnum moss, it is difficult to separate the effect of water content from species. Consequently, we carried out a laboratory based drying experiment where we compared the water repellency of two dominant peatland moss species, Sphagnum and feathermoss, for several burn severity classes including unburned samples. The results suggest that water repellency in moss is primarily controlled by water content, where a sharp threshold exists at gravimetric water contents (GWC) lower than ∼1.4 g g-1. While GWC is shown to be a strong predictor of water repellency, the effect is enhanced by burning. Based on soil water retention curves, we suggest that it is highly unlikely that Sphagnum will exhibit strong hydrophobic conditions under field conditions.

  7. Organic compounds in hot-water-soluble fractions from water repellent soils

    Science.gov (United States)

    Atanassova, Irena; Doerr, Stefan

    2014-05-01

    Water repellency (WR) is a soil property providing hydrophobic protection and preventing rapid microbial decomposition of organic matter entering the soil with litter or plant residues. Global warming can cause changes in WR, thus influencing water storage and plant productivity. Here we assess two different approaches for analysis of organic compounds composition in hot water extracts from accelerated solvent extraction (ASE) of water repellent soils. Extracts were lyophilized, fractionated on SiO2 (sand) and SPE cartridge, and measured by GC/MS. Dominant compounds were aromatic acids, short chain dicarboxylic acids (C4-C9), sugars, short chain fatty acids (C8-C18), and esters of stearic and palmitic acids. Polar compounds (mainly sugars) were adsorbed on applying SPE clean-up procedure, while esters were highly abundant. In addition to the removal of polar compounds, hydrophobic esters and hydrocarbons (alkanes and alkenes particle wettability and C dynamics in soils. Key words: soil water repellency, hot water soluble carbon (HWSC), GC/MS, hydrophobic compounds

  8. Repellent Activity of Eight Essential Oils of Chinese Medicinal Herbs t oBlattella germanica L.

    Directory of Open Access Journals (Sweden)

    Zhi Long Liu

    2011-01-01

    Full Text Available Eight e ssential oil s of Chinese medicinal herbs ( Angelica sinensis , Curuma aeruginosa , Cyperus rotundus , Eucalyptus robusta , Illicium verum , Lindera aggregate , Ocimum basilicum , and Zanthoxylum bungeanum w ere obtained by hydrodistillation and the essential oil of Eucalyptus robusta leaves was analyzed by gas chromatography-mass spectrometry (GC-MS. A total of 22 components of the essential oil of E. robusta were identified. The principal compounds in E . robusta essential oil were α- p inene (28.74% and 1,8- c ineole (27.18%, spathulenol (6.63%, globulol (6.53% and ρ - m enth-1-en-8-ol (5.20%. The 8 essential oil s and two main components, α -pinene and 1, 8-cineole of the essential oil of E. robusta were evaluated repellency against nymphs of the German cockroaches . Strong repellency (Class V was obtained for Cyperus rotundus and Eucalyptus robusta essential oils and α- p inene and 1, 8- c ineole . However, Illicium verum essential oil possessed weak (Class I repellency. At a concentration of 5 ppm, all the 8 essential oils and the two compounds showed repellent activity after one hour exposure. At 1 ppm concentration, essential oil of Cyperus rotundus showed strong repellency and Class IV repellency was obtained for essential oil of E. robusta and the two compounds after one hour exposure. However, essential oils of I . verum and Lindera aggregata showed strong attractiveness to the German cockroaches at a concentration of 1 ppm .

  9. Experimental Investigation of 2D thermal signature and 3D X-Ray Computed Tomography in contrasting Wettable and Water-Repellent Beads

    Science.gov (United States)

    Alsih, Abdulkareem; Flavel, Richard; McGrath, Gavan

    2017-04-01

    This study presents experimental results investigating spatial patterns of infiltration and evaporation in heterogeneous water repellent media. Infrared camera measurements and 3D X-ray computed tomography imaging was performed across wet-dry cycles on glass beads with engineered patches of water repellence. The imaging revealed spatial variability in infiltration and the redistribution of water in the media resulting in differences in relative evaporation rates during drying. It appears that the spatial organization of the heterogeneity play a role in the breakdown of water repellence at the interface of the two media. This suggests a potential mechanism for self-organization of repellency spatial patterns in field soils. At the interface between wettable and water repellent beads a lateral drying front propagates towards the wettable beads from the repellent beads. During this drying the relative surface temperatures change from a relatively cooler repellent media surface to a relatively cooler wettable media surface indicating the changes in evaporative water loss between the beads of varying water repellence. The lateral drying front was confirmed using thermography in a small-scale model of glass beads with chemically induced repellence and then subjected to 3D X-ray imaging. Pore-scale imaging identified the hydrology at the interface of the two media and at the drying front giving insights into the physics of water flow in water repellent soil.

  10. REPELLENT AND OVIPOSITION DETERRENT ACTIVITIES OFTHE ESSENTIAL OIL FROM MIKANIA MICRANTHA AND ITS COMPOUNDS ON PLUTELLA XYLOSTELLA

    Institute of Scientific and Technical Information of China (English)

    Mao-xinZhang; BingLing; Shao-yingChen; Guang-wenLiang; Xiong-feiPang

    2004-01-01

    Repellent and oviposition deterrent activities of the essential oil from Mikania micrantha and five volatile compounds including limonene, a-terpinene, linalool, B-caryophylene and verbenone on the diamondback moth (DBM), Plutella xylostella, was investigated in door and in net-house. The results showed that the essential oil of the M. micrantha had significant repellant effect (at flow 100-180 mL/min) and oviposition deterrent activity at dose 1020 uL/seedling for the DBM. In five volatile compounds, a-terpinene, limonene and linalool had significant effect on repellent and oviposition deterrent of the DBM moths, but verbenone and B-caryophylene, no significantly effect was observed in repellent and oviposition deterrent.

  11. Efficacy of Some Wearable Devices Compared with Spray-On Insect Repellents for the Yellow Fever Mosquito, Aedes aegypti (L.) (Diptera: Culicidae).

    Science.gov (United States)

    Rodriguez, Stacy D; Chung, Hae-Na; Gonzales, Kristina K; Vulcan, Julia; Li, Yiyi; Ahumada, Jorge A; Romero, Hector M; De La Torre, Mario; Shu, Fangjun; Hansen, Immo A

    2017-01-01

    The current Zika health crisis in the Americas has created an intense interest in mosquito control methods and products. Mosquito vectors of Zika are of the genus Aedes, mainly the yellow fever mosquito, Aedes aegypti. L. The use of repellents to alter mosquito host seeking behavior is an effective method for the prevention of mosquito-borne diseases. A large number of different spray-on repellents and wearable repellent devices are commercially available. The efficacies of many repellents are unknown. This study focuses on the efficacy of eleven different repellents in reducing the number of Ae. aegypti female mosquitoes attracted to human bait. We performed attraction-inhibition assays using a taxis cage in a wind tunnel setting. One person was placed upwind of the taxis cage and the mosquito movement towards or away from the person was recorded. The person was treated with various spray-on repellents or equipped with different mosquito repellent devices. We found that the spray-on repellents containing N,N-Diethyl-meta-toluamide and p-menthane-3,8-diol had the highest efficacy in repelling mosquitoes compared to repellents with other ingredients. From the five wearable devices that we tested, only the one that releases Metofluthrin significantly reduced the numbers of attracted mosquitoes. The citronella candle had no effect. We conclude that many of the products that we tested that were marketed as repellents do not reduce mosquito attraction to humans. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

  12. Detection of bluetongue virus in the blood of inoculated calves: comparison of virus isolation, PCR assay, and in vitro feeding of Culicoides variipennis.

    Science.gov (United States)

    MacLachlan, N J; Nunamaker, R A; Katz, J B; Sawyer, M M; Akita, G Y; Osburn, B I; Tabachnick, W J

    1994-01-01

    The interval after infection when bluetongue virus (BTV) was present in the blood of calves inoculated with BTV serotype 10 (BTV 10) was evaluated by virus isolation (VI) in embryonated chicken eggs (ECE), BTV-specific polymerase chain reaction (PCR), and in vitro blood feeding of vector Culicoides variipennis (C.v.) sonorensis. BTV nucleic acid was detected by PCR in blood cells for 16 to 20 weeks after infection whereas infectious virus was detected by VI in ECE for 2 to 8 weeks. BTV was detected in calf blood by in vitro feeding of C.v. sonorensis for only 0 to 2 weeks after inoculation of calves with BTV 10. Selected bloods which were positive by PCR analysis but not by VI in ECE were not infectious for sheep. The data are consistent with the hypothesis that prolonged viremia in BTV-infected cattle results from association of the virus with blood cells, especially erythrocytes. The fact that calf blood that contained viral nucleic acid as determined by PCR analysis, but not infectious virus as determined by VI in ECE, was not infectious for either the insect vector or sheep suggests that cattle whose blood contains BTV nucleic acid but not infectious virus are unimportant to the epidemiology of BTV infection.

  13. 'Natural background' soil water repellency in conifer forests of the north-western USA: Its prediction and relationship to wildfire occurrence

    Science.gov (United States)

    Doerr, S.H.; Woods, S.W.; Martin, D.A.; Casimiro, M.

    2009-01-01

    Soils under a wide range of vegetation types exhibit water repellency following the passage of a fire. This is viewed by many as one of the main causes for accelerated post-fire runoff and soil erosion and it has often been assumed that strong soil water repellency present after wildfire is fire-induced. However, high levels of repellency have also been reported under vegetation types not affected by fire, and the question arises to what degree the water repellency observed at burnt sites actually results from fire. This study aimed at determining 'natural background' water repellency in common coniferous forest types in the north-western USA. Mature or semi-mature coniferous forest sites (n = 81), which showed no evidence of recent fires and had at least some needle cast cover, were sampled across six states. After careful removal of litter and duff at each site, soil water repellency was examined in situ at the mineral soil surface using the Water Drop Penetration Time (WDPT) method for three sub-sites, followed by collecting near-surface mineral soil layer samples (0-3 cm depth). Following air-drying, samples were further analyzed for repellency using WDPT and contact angle (??sl) measurements. Amongst other variables examined were dominant tree type, ground vegetation, litter and duff layer depth, slope angle and aspect, elevation, geology, and soil texture, organic carbon content and pH. 'Natural background' water repellency (WDPT > 5 s) was detected in situ and on air-dry samples at 75% of all sites examined irrespective of dominant tree species (Pinus ponderosa, Pinus contorta, Picea engelmanii and Pseudotsuga menziesii). These findings demonstrate that the soil water repellency commonly observed in these forest types following burning is not necessarily the result of recent fire but can instead be a natural characteristic. The notion of a low background water repellency being typical for long-unburnt conifer forest soils of the north-western USA is

  14. Critical homoclinic orbits lead to snap-back repellers

    International Nuclear Information System (INIS)

    Gardini, Laura; Sushko, Iryna; Avrutin, Viktor; Schanz, Michael

    2011-01-01

    Highlights: → We consider critical homoclinic orbits in continuous and discontinuous maps. → Unbounded homoclinic orbits in maps on unbounded domains are considered as well. → We show that a snapback-repeller (SBR) with a non-critical homoclinic orbit implies chaos. → We show also that a SBR with a critical homoclinic orbit may or may not imply chaos. - Abstract: When nondegenerate homoclinic orbits to an expanding fixed point of a map f:X→X,X subset or equal R n , exist, the point is called a snap-back repeller. It is known that the relevance of a snap-back repeller (in its original definition) is due to the fact that it implies the existence of an invariant set on which the map is chaotic. However, when does the first homoclinic orbit appear? When can other homoclinic explosions, i.e., appearance of infinitely many new homoclinic orbits, occur? As noticed by many authors, these problems are still open. In this work we characterize these bifurcations, for any kind of map, smooth or piecewise smooth, continuous or discontinuous, defined in a bounded or unbounded closed set. We define a noncritical homoclinic orbit and a homoclinic orbit of an expanding fixed point is structurally stable iff it is noncritical. That is, only critical homoclinic orbits are responsible for the homoclinic explosions. The possible kinds of critical homoclinic orbits will be also investigated, as well as their dynamic role.

  15. Repellency of essential oils extracted from Thai native plants against Aedes aegypti (Linn.) and Culex quinquefasciatus (Say).

    Science.gov (United States)

    Phukerd, Ubol; Soonwera, Mayura

    2014-09-01

    Repellent activity of essential oils derived from 10 Thai native plants, belonging to three families were evaluated against female Aedes aegypti and Culex quinquefasciatus and to compare them with a commercial chemical repellents (DEET; N,N-diethyl-3-methylbenzamide 20% w/w; Sketolene Shield). Each test repellent was applied at 1, 5, and 10% concentrations for testing by arm in cage method. The results showed significant differences in repellency among the repellents by mosquito species. The protection time of the essential oils against Ae. aegypti ranged from 3 to 30 min. According to the Culex mosquito, it showed the protection time ranged from 3 to 260 min. 10 % Boesenbergia rotunda essential oil provided the best efficiency, in which protection time was 4.3 h as equal as DEET. The essential oils which exhibited protection time more than 2 h were those of 10% Zingiber zerumbet, Litsea petiolata, Curcuma zedoaria, and Zingiber cassumunar essential oils (3.1, 2.8, 2.6, and 2.3 h, respectively). The biting percentage ranged from 0.9 to 18.0% and 0.8 to 3.6% against Ae. aegypti and Cx. quinquefasciatus, respectively. The results revealed that the potential of essential oil extracted from B. rotunda, Z. zerumbet, L. petiolata, C. zedoaria, and Z. cassumunar had attributes of good repellent and deterred biting. We recommend the five essential oils for further study to develop as commercial repellents.

  16. Synergistic insecticidal and repellent effects of combined pyrethroid and repellent-impregnated bed nets using a novel long-lasting polymer-coating multi-layer technique.

    Science.gov (United States)

    Faulde, Michael K; Nehring, Oliver

    2012-08-01

    New and improved strategies for malaria control and prevention are urgently needed. As a contribution to an optimized personal protection strategy, a novel long-lasting insecticide and repellent-treated net (LLIRN) has been designed by binding combinations of permethrin plus N,N-diethyl-m-toluamide (DEET), or insect repellent 3535 (IR3535), and etofenprox plus DEET, onto fibres of bed net fabric employing a new multi-layer polymer-coating technique. Protective repellent efficacy, toxicological effectiveness and residual activity of 12 LLIRN types have been evaluated by laboratory testing against adult Aedes aegypti. The novel multi-layer LLIRN design allowed simultaneous embedding at concentrations up to 5,930 mg/m(2) for DEET, 3,408 mg/m(2) for IR3535, 2,296 mg/m(2) for permethrin and 2,349 mg/m(2) for etofenprox, respectively. IR3535 layers prevented co-binding of additional pyrethroid-containing polymer layers, thus making pyrethroids plus DEET LLIRNs an ideal combination. All LLIRNs revealed synergistic insecticidal effects which, when measured against concentration controls of the isolated compounds, were significant in all LLIRN types designed. DEET in DEET plus permethrin LLIRNs significantly (p time from 55 to 75 %, the corresponding 100 % kill time (p time of etofenprox from 42 to 50 % (p = 0.004), the 100 % kill time from 25 to 38 % (p biting protection, even at low concentrations. One hundred percent biting and probing protection of stored LLIRNs was preserved for 83 weeks with the 5,930 mg/m(2) DEET and 2,139 mg/m(2) etofenprox LLIRN, for 72 weeks with the 5,002 mg/m(2) DEET and 2,349 mg/m(2) etofenprox LLIRN, for 63 weeks with the 3,590 mg/m(2) DEET and 1,208 mg/m(2) permethrin LLRN, and for 61 weeks with the 4,711 mg/m(2) DEET and 702 mg/m(2) etofenprox LLIRN. Because 100 % bite protection with up to 75 % quicker contact toxicity of pyrethroids were documented, synergistic toxicological and repellent effects of multi-layer polymer

  17. Initial water repellency affected organic matter depletion rates of manure amended soils in Sri Lanka

    Directory of Open Access Journals (Sweden)

    Leelamanie D.A.L.

    2014-12-01

    Full Text Available The wetting rate of soil is a measure of water repellency, which is a property of soils that prevents water from wetting or penetrating into dry soil. The objective of the present research was to examine the initial water repellency of organic manure amended soil, and its relation to the soil organic matter (SOM depletion rates in the laboratory. Soil collected from the Wilpita natural forest, Sri Lanka, was mixed with organic manure to prepare soil samples with 0, 5, 10, 25, and 50% organic manure contents. Locally available cattle manure (CM, goat manure (GM, and Casuarina equisetifolia leaves (CE were used as the organic manure amendments. Organic matter content of soils was measured in 1, 3, 7, 14, and 30 days intervals under the laboratory conditions with 74±5% relative humidity at 28±1°C. Initial water repellency of soil samples was measured as the wetting rates using the water drop penetration time (WDPT test. Initial water repellency increased with increasing SOM content showing higher increasing rate for hydrophobic CE amended samples compared with those amended with CM and GM. The relation between water repellency and SOM content was considered to be governed by the original hydrophobicities of added manures. The SOM contents of all the soil samples decreased with the time to reach almost steady level at about 30 d. The initial SOM depletion rates were negatively related with the initial water repellency. However, all the CE amended samples initially showed prominent low SOM depletion rates, which were not significantly differed with the amended manure content or the difference in initial water repellency. It is explicable that the original hydrophobicity of the manure as well has a potentially important effect on initiation of SOM decomposition. In contrast, the overall SOM depletion rate can be attributed to the initial water repellency of the manure amended sample, however, not to the original hydrophobicity of the amended manure

  18. Long-term breast-feeding in women with type 1 diabetes

    DEFF Research Database (Denmark)

    Stage, E; Nørgård, Hanne; Damm, Peter

    2006-01-01

    Breast-feeding may be more difficult in women with diabetes because of neonatal morbidity and fluctuating maternal blood glucose values. The frequency of long-term breast-feeding and the possible predictors for successful breast-feeding were investigated.......Breast-feeding may be more difficult in women with diabetes because of neonatal morbidity and fluctuating maternal blood glucose values. The frequency of long-term breast-feeding and the possible predictors for successful breast-feeding were investigated....

  19. The Effect of Water Repellent Surface Impregnation on Durability of Cement-Based Materials

    Directory of Open Access Journals (Sweden)

    Peng Zhang

    2017-01-01

    Full Text Available In many cases, service life of reinforced concrete structures is severely limited by chloride penetration until the steel reinforcement or by carbonation of the covercrete. Water repellent treatment on the surfaces of cement-based materials has often been considered to protect concrete from these deteriorations. In this paper, three types of water repellent agents have been applied on the surface of concrete specimens. Penetration profiles of silicon resin in treated concrete have been determined by FT-IR spectroscopy. Water capillary suction, chloride penetration, carbonation, and reinforcement corrosion in both surface impregnated and untreated specimens have been measured. Results indicate that surface impregnation reduced the coefficient of capillary suction of concrete substantially. An efficient chloride barrier can be established by deep impregnation. Water repellent surface impregnation by silanes also can make the process of carbonation action slow. In addition, it also has been concluded that surface impregnation can provide effective corrosion protection to reinforcing steel in concrete with migrating chloride. The improvement of durability and extension of service life for reinforced concrete structures, therefore, can be expected through the applications of appropriate water repellent surface impregnation.

  20. Wet-dry cycles effect on ash water repellency. A laboratory experiment.

    Science.gov (United States)

    Pereira, Paulo; Cerdà, Artemi; Oliva, Marc; Mataix, Jorge; Jordán, Antonio

    2014-05-01

    In the immediate period after the fire, the ash layer has a strong influence on soil hydrological processes, as runoff, infiltration and erosion. Ash is very dynamic in the space and time. Until the first rainfall periods, ash is (re)distributed by the wind. After it can cover the soil surface, infiltrate or transported to other areas by water transport (Pereira et al., 2013a, b). This will have strong implications on nutrient redistribution and vegetation recovery. Ash layer may affect soil water repellency in different ways, depending on fire severity, soil properties and vegetation. Ash produced at low temperatures after low-severity burning is usually hydrophobic (Bodi et al., 2011, 2012). Wet-dry cycles have implications on ash physical and chemical properties, changing their effects in space and time. The aim of this study is to analyse the effects of fire temperature and severity on ash water repellency. Pinus sylvestris needles were collected in a Lithuania forest in Dzukija National Park (53º 54' N and 24º 22' E), transported to laboratory and washed with deionized water to remove soil particles and other residues. Needle samples were dried during 24 hours and exposed to different temperatures: 200, 300, 400 and 500 ºC, during 2 hours. Ash colour was analysed according to the Munsell Soil Color charts. Ash was black (10 YR 2/1) at 200 ºC, very dark grey (10YR 3/1) at 300 ºC, gray (10YR 5/1) at 400 ºC and light gray (10YR 7/1) at 500 ºC. Ten samples of ash released after each treatment were placed in plastic dishes (50 mm in diameter) in an amount enough to form a 5 mm thick layer, and ash water repellency was measured according to the Water Drop Penetration Test. Later, ash was carefully wetted with 15 ml of deionized water and placed in an oven during 4 days (96 hours), as in Bodí et al. (2012). This procedure was repeated 5 times in order to observe the effects of wet-dry cycles in ash water repellency. The results showed significant differences

  1. Glytube: a conical tube and parafilm M-based method as a simplified device to artificially blood-feed the dengue vector mosquito, Aedes aegypti.

    Directory of Open Access Journals (Sweden)

    André Luis Costa-da-Silva

    Full Text Available Aedes aegypti, the main vector of dengue virus, requires a blood meal to produce eggs. Although live animals are still the main blood source for laboratory colonies, many artificial feeders are available. These feeders are also the best method for experimental oral infection of Ae. aegypti with Dengue viruses. However, most of them are expensive or laborious to construct. Based on principle of Rutledge-type feeder, a conventional conical tube, glycerol and Parafilm-M were used to develop a simple in-house feeder device. The blood feeding efficiency of this apparatus was compared to a live blood source, mice, and no significant differences (p = 0.1189 were observed between artificial-fed (51.3% of engorgement and mice-fed groups (40.6%. Thus, an easy to assemble and cost-effective artificial feeder, designated "Glytube" was developed in this report. This simple and efficient feeding device can be built with common laboratory materials for research on Ae. aegypti.

  2. Spatial repellents: from discovery and development to evidence-based validation

    Directory of Open Access Journals (Sweden)

    Achee Nicole L

    2012-05-01

    Full Text Available Abstract International public health workers are challenged by a burden of arthropod-borne disease that remains elevated despite best efforts in control programmes. With this challenge comes the opportunity to develop novel vector control paradigms to guide product development and programme implementation. The role of vector behaviour modification in disease control was first highlighted several decades ago but has received limited attention within the public health community. This paper presents current evidence highlighting the value of sub-lethal agents, specifically spatial repellents, and their use in global health, and identifies the primary challenges towards establishing a clearly defined and recommended role for spatial repellent products in disease control.

  3. Repellents and New “Spaces of Concern” in Global Health

    Science.gov (United States)

    Kelly, Ann H.; Koudakossi, Hermione N. Boko; Moore, Sarah J.

    2017-01-01

    ABSTRACT Today, malaria prevention hinges upon two domestic interventions: insecticide-treated bed nets and indoor residual spraying. As mosquitoes grow resistant to these tools, however, novel approaches to vector control have become a priority area of malaria research and development. Spatial repellency, a volumetric mode of action that seeks to reduce disease transmission by creating an atmosphere inimical to mosquitoes, represents one way forward. Drawing from research that sought to develop new repellent chemicals in conversation with users from sub-Saharan Africa and the United States, we consider the implications of a non-insecticidal paradigm of vector control for how we understand the political ecology of malaria. PMID:28594568

  4. Blood-feeding patterns of native mosquitoes and insights into their potential role as pathogen vectors in the Thames estuary region of the United Kingdom.

    Science.gov (United States)

    Brugman, V A; Hernández-Triana, L M; England, M E; Medlock, J M; Mertens, P P C; Logan, J G; Wilson, A J; Fooks, A R; Johnson, N; Carpenter, S

    2017-03-27

    The range of vertebrate hosts on which species of mosquito blood-feed is an important parameter for identifying potential vectors and in assessing the risk of incursion and establishment of vector-borne pathogens. In the United Kingdom, studies of mosquito host range have collected relatively few specimens and used techniques that could only broadly identify host species. This study conducted intensive collection and analysis of mosquitoes from a grazing marsh environment in southeast England. This site provides extensive wetland habitat for resident and migratory birds and has abundant human nuisance biting mosquitoes. The aim was to identify the blood-feeding patterns of mosquito species present at the site which could contribute to the transmission of pathogens. Twice-weekly collections of mosquitoes were made from Elmley Nature Reserve, Kent, between June and October 2014. Mosquitoes were collected using resting boxes, by aspiration from man-made structures and using a Mosquito Magnet Pro baited with 1-octen-3-ol. Blood-fed specimens were classified according to the degree of blood meal digestion using the Sella scale and vertebrate origin determined using sequencing of a fragment of the mitochondrial cytochrome C oxidase subunit I gene. Mosquitoes that were morphologically cryptic were identified to species level using multiplex PCR and sequencing methods. A total of 20,666 mosquitoes of 11 species were collected, and 2,159 (10.4%) were blood-fed (Sella scale II-VI); of these 1,341 blood-fed specimens were selected for blood meal analysis. Vertebrate origin was successfully identified in 964 specimens (72%). Collections of blood-fed individuals were dominated by Anopheles maculipennis complex (73.5%), Culiseta annulata (21.2%) and Culex pipiens form pipiens (10.4%). Nineteen vertebrate hosts comprising five mammals and 14 birds were identified as hosts for mosquitoes, including two migratory bird species. Feeding on birds by Culex modestus and Anopheles

  5. Effects of insemination and blood-feeding on locomotor activity of Aedes albopictus and Aedes aegypti (Diptera: Culicidae) females under laboratory conditions.

    Science.gov (United States)

    Lima-Camara, Tamara Nunes; Lima, José Bento Pereira; Bruno, Rafaela Vieira; Peixoto, Alexandre Afranio

    2014-07-02

    Dengue is an arbovirus disease transmitted by two Aedes mosquitoes: Ae. aegypti and Ae. albopictus. Virgin females of these two species generally show a bimodal and diurnal pattern of activity, with early morning and late afternoon peaks. Although some studies on the flight activity of virgin, inseminated and blood-fed Ae. aegypti females have been carried out under laboratory conditions, little is known about the effects of such physiological states on the locomotor activity of Ae. albopictus and Ae. aegypti females. The aim of this study was to analyze, under laboratory conditions, the effects of insemination and blood-feeding on the locomotor activity of Ae. albopictus and Ae. aegypti females under LD 12:12, at 25°C. Both Ae. albopictus and Ae. aegypti females were obtained from established laboratory colonies. Control groups were represented by virgin/unfed Ae. albopictus and Ae. aegypti females. Experiments were conducted under laboratory conditions, using an activity monitor that registers individual activity every thirty minutes. Virgin/unfed Ae. albopictus and Ae. aegypti females showed a diurnal and bimodal pattern of locomotor activity, with peaks at early morning and late afternoon. Insemination and blood-feeding significantly decreased the locomotor activity of Ae. aegypti females, but inseminated/blood-fed Ae. aegypti and Ae. albopictus females showed a similar significant decrease on the locomotor activity compared to virgin/unfed females. This study is the first demonstration of the effects of insemination and blood-feeding on the locomotor activity of Ae. albopictus and Ae. aegypti females under artificial conditions. Data suggest that Ae. albopictus and Ae. aegypti females respond in different ways to physiological status changes and such divergence between these two dengue vectors, associated with several ecological differences, could be related to the greater dengue vectorial capacity of Ae. aegypti in Americas in comparison to Ae. albopictus.

  6. Repelling mosquitoes with essential oils

    Science.gov (United States)

    Riley, L.

    2017-12-01

    Mosquitoes carry diseases than can lead to serious illness and death. According to the World Health Organization, mosquitoes infect over 300 million people a year with Malaria and Dengue Fever, two life threatening diseases vectored by mosquitoes. Although insecticides are the most effective way to control mosquitoes, they are not always environmentally friendly. Therefore, alternative tactics should be considered. In this study, we looked at the repellency of various essential oils on female Aedes aegypti through a series of laboratory assays.

  7. Assessment of the repellent effect of Lippia alba essential oil and major monoterpenes on the cattle tick Rhipicephalus microplus.

    Science.gov (United States)

    Lima, A da Silva; Carvalho, J F de; Peixoto, M G; Blank, A F; Borges, L M F; Costa Junior, L M

    2016-03-01

    The control of Rhipicephalus microplus (Ixodida: Ixodidae) is achieved using synthetic acaricides. However, resistant tick populations are widespread around the world. Plant essential oils can act as repellents, keeping ticks away from hosts and decreasing the selection pressure on synthetic acaricides. The aim of this study was to evaluate the in vitro repellent effect of Lippia alba essential oil on R. microplus larvae. Leaves from two L. alba genotypes maintained under the same agronomic and environmental conditions were collected. Essential oil was extracted by hydrodistillation and analysed by gas chromatography-mass spectrometry (GC-MS). The major monoterpenes detected in the chemical analysis were commercially acquired and tested. For the repellency test, a glass rod was vertically fixed to measure active climbing of approximately 30 R. microplus larvae aged 14-21 days in response to essential oils and monoterpenes. Repellency was evaluated at 1 h, 3 h and 5 h after treatment. Variation in repellent action was detected between the genotypes. The major monoterpenes identified in the essential oils (limonene and carvone) showed low repellent effects in comparison with intact essential oils. Thus, the present results showed that L. alba essential oil contains bioactive compounds with great repellent activity against ticks that varies according to the plant genotype. © 2015 The Royal Entomological Society.

  8. La Crosse virus infection alters blood feeding behavior in Aedes triseriatus and Aedes albopictus (Diptera: Culicidae).

    Science.gov (United States)

    Jackson, Bryan T; Brewster, Carlyle C; Paulson, Sally L

    2012-11-01

    The effects of La Crosse virus (LACV) infection on blood feeding behavior in Aedes triseriatus (Say) and Aedes albopictus (Skuse) were investigated in the laboratory by measuring the size of the bloodmeal imbibed and the extent of refeeding by virus-infected and uninfected mosquitoes. LACV-infected Ae. triseriatus and Ae. albopictus took significantly less blood compared with uninfected mosquitoes. Twice as many virus-infected Ae. triseriatus mosquitoes refed compared with uninfected individuals (18 vs. 9%; P < 0.05); however, virus infection had no significant effect on the refeeding rate of Ae. albopictus. Reduction in bloodmeal size followed by an increased avidity for refeeding may lead to enhanced horizontal transmission of the LACV by its principal vector, Ae. triseriatus.

  9. Repellent activity of fractioned compounds from Chamaecyparis nootkatensis essential oil against nymphal Ixodes scapularis (Acari: Ixodidae).

    Science.gov (United States)

    Dietrich, Gabrielle; Dolan, Marc C; Peralta-Cruz, Javier; Schmidt, Jason; Piesman, Joseph; Eisen, Rebecca J; Karchesy, Joseph J

    2006-09-01

    Preliminary repellent activity of 14 natural products isolated from essential oil components extracted from the heartwood of Alaska yellow cedar, Chamaecyparis nootkatensis (D. Don) Spach., were evaluated against nymphal Ixodes scapularis Say in a laboratory bioassay and compared with technical grade N,N-diethyl-3-methylbenzamide (deet). Four hours after treatment, nootkatone and valencene-13-ol had repellent concentration (RC)50 values of 0.0458 and 0.0712% (wt:vol), respectively; two additional Alaska yellow cedar compounds, nootkatone 1 --> 10 epoxide and carvacrol had reported RC50 values of 0.0858 and 0.112%, respectively. The observed RC50 value for deet was 0.0728% (wt:vol). Although not statistically significantly more active than deet, the ability of these natural products to repel ticks at relatively low concentrations may represent a potential alternative to synthetic commercial repellents.

  10. Repellent effects of the essential oils of Cymbopogon citratus and Tagetes minuta on the sandfly, Phlebotomus duboscqi.

    Science.gov (United States)

    Kimutai, Albert; Ngeiywa, Moses; Mulaa, Margaret; Njagi, Peter G N; Ingonga, Johnstone; Nyamwamu, Lydia B; Ombati, Cyprian; Ngumbi, Philip

    2017-02-15

    The sandfly, Phlebotomus duboscqi is a vector of zoonotic cutaneous leishmaniasis (ZCL) that is an important public health problem in Eastern Africa. Repellents have been used for protection of humans against vectors of ZCL and other vectors that transmit killer diseases including malaria, Rift Valley fever, dengue, and yellow fever. The repellent effects of different doses of the essential oils from the lemon grass, Cymbopogon citratus and Mexican marigold, Tagetes minuta were evaluated in a two-chamber bioassay against 3- to 7-day-old unfed females of P. duboscqi in the laboratory. The results were compared with those that were obtained when test animals were treated with an equivalent dose of diethyl-3-methylbenzamide, which is a repellent that is commonly used as a positive control. Overall, percentage repellency increased with increasing doses of the essential oils while biting rates decreased with increasing concentrations of the oils. Further, the oil of C. citratus was more potent than that of T. minuta with regard to protection time and biting deterrence. The effective doses at 50% (ED 50 ) and at 90% (ED 90 ) for the oil of C. citratus, were 0.04 and 0.79 mg/ml, respectively. Those of the oil of T. minuta were 0.10 and 12.58 mg/ml. In addition, the percentage repellency of 1 mg/ml of the essential oils of C. citratus and T. minuta against sandflies was 100% and 88.89%, respectively. A lower dose of 0.5 mg/ml of the oils, elicited 89.13% repellency for C. citratus and 52.22% for T. minuta. The laboratory tests showed that the essential oils of the two plants were highly repellent to adult sand flies, P. duboscqi. Thus, the two essential oils are candidate natural repellents that can be used against P. duboscqi due to their high efficacy at very low doses, hence, the envisaged safety in their use over chemical repellents. It remains to carry out clinical studies on human subjects with appropriate formulations of the oils prior to recommending their

  11. Effect of Various Feed Phosphates on Biochemical Indices of Blood and Mineral Composition of Bones in Finishing Pigs

    Directory of Open Access Journals (Sweden)

    Zbigniew Dobrzański

    2010-01-01

    Full Text Available The aim of this study was to evaluate the effect of three different chemical feed phosphates on the blood biochemical indicators and the content of main minerals of bones in finishing pigs. Over a period of 85 days of fattening, monocalcium (MCP, Finnish product, dicalcium (DCP, Polish product and calcium-sodium (CSP, Russian product phosphates were used in fattener feeding. The feeding was based on standard mixtures of starter, grower and finisher type. Dicalcium phosphate was produced according to the new, pro-ecological technology based on phosphoric acid. The content of Ca, Na, P, solubility of P in citric acid, and the concentration of undesirable substances (As, Cd, F, Hg and Pb were determined in feed phosphates. At the end of the fattening period, blood was collected from 36 finishing pigs (12 from each group and the following biochemical indicators were determined in the serum: enzymatic activity of aspartate aminotransferase (AST, alanine aminotransferase (ALT, γ-glutamyltransferase (GGT, creatine kinase (CK, lactic dehydrogenase (LDH, lactic acid (LA; the concentration of total protein, albumins, glucose, urea, creatinine, content of triglycerides, cholesterol and its high density lipoproteins (HDL and low density lipoproteins (LDL fractions, and mineral components concentration (Ca, Cl, Cu, Fe, K, Mg, Na, P, Zn. Basic macroelement content (Ca, Mg, P was determined in the thigh bones from 30 pigs (10 from each group. Significant differences (p < 0.05 between groups were observed only in some biochemical indicators, i.e. CK, LDH and LA. The highest content of Ca, Mg and P was found in the bones of pigs fed mixtures supplemented with DCP which indicates improved bioavailability of main macroelements from that phosphate.

  12. Establishment of the biochemical and endocrine blood profiles in the Majorera and Palmera dairy goat breeds: the effect of feed restriction.

    Science.gov (United States)

    Lérias, Joana R; Peña, Raquel; Hernández-Castellano, Lorenzo E; Capote, Juan; Castro, Noemí; Argüello, Anastasio; Araújo, Susana S; Saco, Yolanda; Bassols, Anna; Almeida, André M

    2015-11-01

    Feed restriction, and seasonal weight loss (SWL), are major setbacks for animal production in the tropics and the Mediterranean. They may be solved through the use of autochthonous breeds particularly well adapted to SWL. It is therefore of major importance to determine markers of tolerance to feed restriction of putative use in animal selection. Two indigenous breeds from the Canary Islands, Palmera and Majorera, are commonly used by dairy goat farmers and, interestingly, have different phenotype characteristics albeit with a common ancestry. Indeed, Majorera is well adapted to feed restriction whereas the Palmera is susceptible to feed restriction. In addition, regardless of their importance in dairy production, there are only a limited number of reports relating to these breeds and, to the best of our knowledge, there is no description of their blood metabolite standard values under control conditions or as affected by feed restriction. In this study we analysed the blood metabolite profiles in Majorera and Palmera goats aiming to establish the differential responses to feed restriction between the two breeds and to characterise their metabolite standard values under control conditions. We observed significant differences in creatinine, urea, non-esterified fatty acids (NEFAs), cholesterol, IGF-1 and T3 due to underfeeding. Furthermore, a PCA analysis, revealed that animals submitted to undernutrition could be distinguished from the control groups, with the formation of three separate clusters (Palmera individuals after 22 d of subnutrition (PE22); Majorera individuals after 22 d of subnutrition (ME22) and animals assigned to control conditions (MC0, MC22, PC0 and PC22)), highlighting different responses of the two breeds to undernutrition.

  13. Chemical composition and repellency of essential oils from four medicinal plants against Ixodes ricinus nymphs (Acari: Ixodidae).

    Science.gov (United States)

    El-Seedi, Hesham R; Khalil, Nasr S; Azeem, Muhammad; Taher, Eman A; Göransson, Ulf; Pålsson, Katinka; Borg-Karlson, Anna-Karin

    2012-09-01

    In our search for effective tick repellents from plant origin, we investigated the effect of essential oils of four medicinal and culinary plants belonging to the family Lamiaceae on nymphs of the tick Ixodes ricinus (L.). The essential oils of the dry leaves of Rosmarinus officinalis (Rosemary) (L.), Mentha spicata (Spearmint) (L.), Origanum majorana (Majoram) (L.), and Ocimum basilicum (Basil) (L.) were isolated by steam distillation and 15 microg/cm2 concentration of oils was tested against ticks in a laboratory bioassay. The oils of R. officinalis, M. spicata, and O. majorana showed strong repellency against the ticks 100, 93.2, and 84.3%, respectively, whereas O. basilicum only showed 64.5% repellency. When tested in the field, the oils of R. officinalis and M. spicata showed 68.3 and 59.4% repellency at a concentration of 6.5 microg/cm2 on the test cloths. The oils were analyzed by gas chromatography mass spectrometry and the major compounds from the most repellent oils were 1,8-cineole, camphor, linalool, 4-terpineol, borneol, and carvone.

  14. Blood-feeding patterns of the Culex pipiens complex in Sacramento and Yolo Counties, California.

    Science.gov (United States)

    Montgomery, Matthew J; Thiemann, Tara; Macedo, Paula; Brown, David A; Scott, Thomas W

    2011-03-01

    Mosquitoes in the Culex pipiens complex are competent vectors of West Nile virus (WNV; family Flaviviridae, genus Flavivirus) in the laboratory, and field-collected mosquitoes have tested positive for the virus in California and elsewhere. A better understanding of Cx. pipiens complex blood-feeding patterns will help define the threat that these mosquitoes pose to human health and their role in WNV amplification in northern California. We collected blood-engorged Cx. pipiens complex mosquitoes from resting sites near and away from human habitation in Sacramento and Yolo Counties. Cytochrome c oxidase 1 gene sequences were used to identify the vertebrate species from which blood meals were taken. Of 330 engorged mosquitoes collected at 28 sites from June through August 2007 and May through August 2008, >99% fed on an avian host. Three mosquitoes contained bovine blood and none had fed on a human. American Robins (Turdus migratorius) were bitten most often, and the proportion of American Robin blood meals increased significantly over the summer. Other important avian hosts included House Finches (Carpodacus mexicanus), Barn Swallows (Hirundo rustica), Western Meadowlarks (Sturnella neglecta), and Mourning Doves (Zenaida macroura). In rural areas, Barn Swallows, Brewer's Blackbirds (Euphagus cyanocephalus), and House Sparrows (Passer domesticus) were frequent hosts. In settings near human habitation, Mourning Doves and Western Meadowlarks were common hosts. Our data indicate that in north central California mosquitoes in the Cx. pipiens complex may be more important as epiornitic than epidemic vectors of WNV.

  15. Field evaluation of the Off! Clip-on Mosquito Repellent (metofluthrin) against Aedes albopictus and Aedes taeniorhynchus (Diptera: Culicidae) in northeastern Florida.

    Science.gov (United States)

    Xue, Rui-De; Qualls, Whitney A; Smith, Michael L; Gaines, Marcia K; Weaver, James H; Debboun, Mustapha

    2012-05-01

    Repellent efficacy of the Off! Clip-on Mosquito Repellent device (S. C. Johnson and Son, Inc., Racine, WI) containing Metofluthrin was evaluated on six human volunteers against the container-breeding mosquito Aedes albopictus (Skuse) and the salt marsh mosquito Aedes taeniorhynchus (Wiedemann) at two field locations in northeastern Florida. The device repelled mosquitoes by releasing a vaporized form of the pyrethroid insecticide metofluthrin ([AI] 31.2%) and provided 70% protection from Ae. albopictus bites for > 3 h. For the second field trial, a repellent device that was used in the first trial was tested after being open for >1 wk. This device provided 79% protection from Ae. taeniorhynchus bites for 3 h. Our field results showed that the repellent device was 70 and 79% effective at repelling Ae. albopictus and Ae. taeniorhynchus from human test subjects in both field locations in northeastern Florida.

  16. experimental investigation of flow pattern around repelling

    African Journals Online (AJOL)

    A. Mahdieh NajafAbadi and M. M. Bateni

    2017-09-01

    Sep 1, 2017 ... FLOW-3D® software used to simulate flow pattern. The simulation was .... separated into separation zone, shear layer, vortices zone, end point of vorticity zone and primary flow zone. In the figure, b1 and b2 denote ... closer to the wall for the attractive spur dike. For case of the repelling spur dike, transverse.

  17. Studies on repellent activity of seed oils alone and in combination on mosquito, Aedes aegypti.

    Science.gov (United States)

    Mukesh, Y; Savitri, P; Kaushik, R; Singh, N P

    2014-09-01

    The study was undertaken to investigate the relative repellency of Pongamia pinnata and Azadirachta indica seed oils on vector mosquito, Aedes aegypti under laboratory conditions. The repellents were formulated into 3 groups: seed oils, their mixture and combination of seed oils with three carrier oils viz. olive, mustard and coconut oil. Different formulations of each oil were tested at the concentrations of 1% and 5% on human baits. Efficiency was assessed, based on the total protection time; biting rate and percent protection provided by each formulation. Results showed that 5% formulation of the Pongamia pinnata and Azadirachta indica seed oils, mixed in 1:1 ratio exhibited highest percentage repellency of 85%, protection time of 300 min and bite rate of 6%. 5% concentration of A. indica and P. pinnata seed oil in mustard oil base offered 86.36% and 85% protection respectively with total protection time of 230 and 240 min respectively. The study confirms that Azadirachta indica and Pongamia pinnata have mosquito-repellent potential. When mixed in different ratios or with some carrier oil their efficacy increases 2-fold in some cases. These formulations are very promising for topical use (> 5 hrs complete protection) and are comparable to the protection provided by advanced Odomos mosquito repellent cream available commercially and thus are recommended for field trial.

  18. Vegetation type and the presence of ash as factors in the evolution of soil water repellency after a forest fire

    Directory of Open Access Journals (Sweden)

    P. Jiménez-Pinilla

    2013-05-01

    Full Text Available After wildfires, burning may induce the occurrence of soil water repellency. Soil water repellency may vary in space and time in function of vegetation, the presence of ash and soil moisture. This study analyzes the evolution of fire-induced soil water repellency in function of these factors, and proposes measures to promote the restoration of fire-affected soils. Burnt and unburnt (control soil plots under pine and shrub from a recently burned area (Gorga, Alicante, SE Spain were established. Three treatments were applied: in some of the plots, the original ash layer was kept on the ground; in a second group, the ash layer was removed for simulating the effects of erosion; finally, in a third group, percolating irrigation was conducted to simulate a possible good input of water into the soil profile after burning, that could occur if the first rains were with high quantity but low intensity. During the dry season, soil moisture content was significantly lower in burned plots due to fire-induced water repellency and reduced vegetation cover. During the wet season, soil moisture decreased in the control unburnt plots due to direct evaporation of water intercepted by vegetation and consumption by roots. Fire increased soil water repellency only in plots under pine. Water repellency decreased during the wet season, disappearing in January and reappearing after declining rainfalls. This baseline recovery of soil water repellency was lower where ash removal was simulated. In unburned plots, seasonal fluctuations were less important. In general, ash removal promotes a rapid reduction of water repellency, since it can induce washing of hydrophobic compounds. Irrigation performed immediately after the fire also contributed to decreased water repellency.

  19. Blood-feeding preferences of Aedes albopictus (Diptera: Culicidae) in urban and rural settings within the province of Rome, Italy.

    Science.gov (United States)

    Valerio, L; Marini, F; Bongiorno, G; Facchinelli, L; Pombi, M; Caputo, B; Maroli, M; della Torre, A

    2008-06-01

    We here report the results of field trials carried out in Rome with the aim to obtain data on the feeding behaviour of Aedes albopictus, in relation to different availability and abundance of putative hosts. Human Blood Index values were found higher than 75% in urban areas, where humans represented the most abundant hosts, and lower than 60% in rural areas, where host alternative to humans were frequent. The overall results confirm the generalist feeding-behaviour shown by this species in its original range of distribution and highlighting its high potential as vector of human pathogens in urban areas of Italy.

  20. Fresh, dried or smoked? repellent properties of volatiles emitted from ethnomedicinal plant leaves against malaria and yellow fever vectors in Ethiopia

    Directory of Open Access Journals (Sweden)

    Dube Fitsum

    2011-12-01

    Full Text Available Abstract Background In the search for plant-based mosquito repellents, volatile emanations were investigated from five plant species, Corymbia citriodora, Ocimum suave, Ocimum lamiifolium, Olea europaea and Ostostegia integrifolia, traditionally used in Ethiopia as protection against mosquitoes. Methods The behaviour of two mosquitoes, the malaria vector Anopheles arabiensis and the arbovirus vector Aedes aegypti, was assessed towards volatiles collected from the headspace of fresh and dried leaves, and the smoke from burning the dried leaves in a two-choice landing bioassay and in the background of human odour. Results Volatile extracts from the smoke of burning dried leaves were found to be more repellent than those from fresh leaves, which in turn were more repellent to mosquitoes than volatiles from dried leaves. Of all smoke and fresh volatile extracts, those from Co. citriodora (52-76% and Oc. suave (58-68% were found to be the most repellent, Os. integrifolia (29-56% to be intermediate while Ol. europaea (23-40% and Os. integrifolia (19-37% were the least repellent. One volatile present in each of the fresh leaf extracts of Co. citriodora, Oc. suave and Os. integrifolia was ß-ocimene. The levels of ß-ocimene reflected the mosquito repellent activity of these three fresh leaf extracts. Female host-seeking mosquitoes responded dose-dependently to ß-ocimene, both physiologically and behaviourally, with a maximal behavioural repulsion at 14% ß-ocimene. ß-ocimene (14% repels mosquitoes in our 6-minute landing assays comparable to the synthetic insect repellent N,N-diethyl-m-toluamide (10% DEET. Conclusions Volatiles in the smoke of burning as well as fresh leaves of Co. citriodora and Oc. suave have significant repellent properties against host seeking An. arabiensis and Ae. aegypti mosquitoes. ß-ocimene, present in the fresh leaf headspace of Co. citriodora, Oc. suave and Os. integrifolia, is a significantly effective volatile mosquito

  1. Responses of lone star tick (acari: ixodidae) nymphs to the repellent deet applied in acetone and ethanol solutions in vitro bioassays

    Science.gov (United States)

    Behavioral bioassays remain a standard tool in the discovery, development, and registration of repellents. Although tick repellent bioassays tend to be rather uncomplicated, several factors can influence their outcomes. Typically repellent bioassays use a solvent, such as acetone or ethanol, to disp...

  2. Effects of a short-term feed restriction on growth performance, blood metabolites and hepatic IGF-1 levels in growing rabbits

    Directory of Open Access Journals (Sweden)

    J. Lu

    2017-09-01

    Full Text Available A total of 144 weaned hybrid HYLA rabbits (40-day-old were randomly divided into 4 groups, to investigate the effects of the intensity of one week’s feed restriction on short- and medium-term growth performance, blood metabolites and hepatic IGF-1 in growing rabbits. Restricted groups were fed with 30% (Group L30, 50% (Group L50 70% (Group L70 of ad libitum feeding for 1 wk and then fed ad libitum until the end of the experiment (75 d of age. The control group (Group AL was fed ad libitum throughout the experiment. Total feed intake (–15.8% and feed conversion ratio (–13.2% were lower in the L50 than in the AL group (P0.05 for these parameters. Total weight gain did not significantly differ among the 4 experimental groups (38.5 g/d; P>0.05. At the end of the feed restriction period, the total serum protein level (P=0.01 was higher in restricted rabbits than AL rabbits (P0.05 throughout the experiment. In conclusion, a short-term feed restriction improves feed conversion ratio in a lasting way, transiently alters serum protein and IFG-1 levels and leads to compensatory growth in growing rabbits.

  3. Repellency property of long chain aliphatic methyl ketones against ...

    African Journals Online (AJOL)

    -tridecanone and 2-pentadecanone) were more effective than compounds with even carbon atoms (2-decanone and 2- dodecanone). Comparable repellency activity of 2-tridecanone to DEET show that, it may save as Anopheles gambiae s.s. ...

  4. Effect of feeding different levels of Azolla pinnata on blood biochemicals, hematology and immunocompetence traits of Chabro chicken

    Directory of Open Access Journals (Sweden)

    Deepesh Bharat Mishra

    2016-02-01

    Full Text Available Aim: The present study was conducted to see the effect of feeding different levels of Azolla meal on blood biochemicals, hematology and immunocompetence traits of Chabro chicken. Materials and Methods: The study was conducted on 160 Chabro chicks, which were randomly divided into four treatment groups each with four replicates of 10 birds. The first treatment (T1 served as a control in which basal diets was offered without Azolla supplementation while in T2, T3, and T4 groups, basal diet was replaced with Azolla meal at 5%, 7.5%, and 10% levels, respectively. A feeding trial was conducted upto 8 weeks. At the last week of trial, blood samples were collected randomly from one bird of each replicate and plasma was separated to estimate certain biochemical parameters, some blood metabolites, minerals and enzymes like alanine aminotransferase and aspartate aminotransferase (AST. Hematological parameters such as hemoglobin, packed cell volume, total leukocytes count and differential leukocytes count were estimated in fresh blood just after collection. The humoral immune response was measured against sheep red blood cells,and cell-mediated immune response was measured against phyto hemagglutinin lectin from Phaseolus vulgaris (PHA-P. Results: The study showed that hematological profile of the Chabro bird was not affected by any treatment except heterophil and lymphocyte which was found higher in T2 and T3 groups and eosinophil was found higher in a T3 group than control. Blood glucose, creatinine, cholesterol, total protein, albumin, uric acid, and triglycerides were found similar in all the groups and within the normal values for broiler chicken. Liver enzymes and macro mineral content in blood were found similar in all the treatment groups and within normal physiological range. Although AST was found higher in 10% replacement group than control, the value was within normal range for broiler chicken. Although antibody titer was found similar in all

  5. Identifying the effective concentration for spatial repellency of the dengue vector Aedes aegypti.

    Science.gov (United States)

    Achee, Nicole; Masuoka, Penny; Smith, Philip; Martin, Nicholas; Chareonviryiphap, Theeraphap; Polsomboon, Suppaluck; Hendarto, Joko; Grieco, John

    2012-12-28

    Current efforts are underway to quantify the chemical concentration in a treated air space that elicits a spatial repellent (deterrent) response in a vector population. Such information will facilitate identifying the optimum active ingredient (AI) dosage and intervention coverage important for the development of spatial repellent tools--one of several novel strategies being evaluated for vector-borne disease control. This study reports initial findings from air sampling experiments conducted under field conditions to describe the relationship between air concentrations of repellent AIs and deterrent behavior in the dengue vector, Aedes aegypti. Air samples were taken inside and outdoors of experimental huts located in Pu Tuey Village, Kanchanaburi Province, Thailand in conjunction with mosquito behavioral evaluations. A mark-release-recapture study design using interception traps was used to measure deterrency of Ae. aegypti against 0.00625% metofluthrin coils and DDT-treated fabric (2g/m2) within separate experimental trials. Sentinel mosquito cohorts were positioned adjacent to air sampling locations to monitor knock down responses to AI within the treated air space. Air samples were analyzed using two techniques: the U.S. Environmental Protection Agency (USEPA) Compendium Method TO-10A and thermal desorption (TD). Both the USEPA TO-10A and TD air sampling methods were able to detect and quantify volatized AIs under field conditions. Air samples indicated concentrations of both repellent chemicals below thresholds required for toxic responses (mortality) in mosquitoes. These concentrations elicited up to a 58% and 70% reduction in Ae. aegypti entry (i.e., deterrency) into treated experimental huts using metofluthrin coils and DDT-treated fabric, respectively. Minimal knock down was observed in sentinel mosquito cohorts positioned adjacent to air sampling locations during both chemical evaluations. This study is the first to describe two air sampling

  6. Identifying the effective concentration for spatial repellency of the dengue vector Aedes aegypti

    Directory of Open Access Journals (Sweden)

    Achee Nicole

    2012-12-01

    Full Text Available Abstract Background Current efforts are underway to quantify the chemical concentration in a treated air space that elicits a spatial repellent (deterrent response in a vector population. Such information will facilitate identifying the optimum active ingredient (AI dosage and intervention coverage important for the development of spatial repellent tools – one of several novel strategies being evaluated for vector-borne disease control. This study reports initial findings from air sampling experiments conducted under field conditions to describe the relationship between air concentrations of repellent AIs and deterrent behavior in the dengue vector, Aedes aegypti. Methods Air samples were taken inside and outdoors of experimental huts located in Pu Tuey Village, Kanchanaburi Province, Thailand in conjunction with mosquito behavioral evaluations. A mark-release-recapture study design using interception traps was used to measure deterrency of Ae. aegypti against 0.00625% metofluthrin coils and DDT-treated fabric (2g/m2 within separate experimental trials. Sentinel mosquito cohorts were positioned adjacent to air sampling locations to monitor knock down responses to AI within the treated air space. Air samples were analyzed using two techniques: the U.S. Environmental Protection Agency (USEPA Compendium Method TO-10A and thermal desorption (TD. Results Both the USEPA TO-10A and TD air sampling methods were able to detect and quantify volatized AIs under field conditions. Air samples indicated concentrations of both repellent chemicals below thresholds required for toxic responses (mortality in mosquitoes. These concentrations elicited up to a 58% and 70% reduction in Ae. aegypti entry (i.e., deterrency into treated experimental huts using metofluthrin coils and DDT-treated fabric, respectively. Minimal knock down was observed in sentinel mosquito cohorts positioned adjacent to air sampling locations during both chemical evaluations. Conclusions

  7. Oil-Repellent Antifogging Films with Water-Enabled Functional and Structural Healing Ability.

    Science.gov (United States)

    Xu, Fuchang; Li, Xiang; Li, Yang; Sun, Junqi

    2017-08-23

    Healable oil-repellent antifogging films are fabricated by layer-by-layer assembly of hyaluronic acid (HA) and branched poly(ethylenimine) (bPEI), followed by immersion in the aqueous solutions of perfluorooctanesulfonic acid potassium salt (PFOS). The loading of PFOS endows the HA/bPEI films with oil repellency while maintaining its original hydrophilicity. The resulting films have an excellent antifogging ability, and various organic liquids can easily slide down the slightly tilted films (touch screens, antigraffiti coatings for signs and shop windows, and antifogging coatings for lenses, mirrors, and windshields.

  8. The distribution and function of serotonin in the large milkweed bug, Oncopeltus fasciatus. a comparative study with the blood-feeding bug, Rhodnius prolixus.

    Science.gov (United States)

    Miggiani, L; Orchard, I; TeBrugge, V

    1999-11-01

    The blood-feeding hemipteran, Rhodnius prolixus, ingests a large blood meal at the end of each larval stage. To accommodate and process this meal, its cuticle undergoes plasticisation, and its gut and Malpighian tubules respectively absorb and secrete a large volume of water and salts for rapid diuresis. Serotonin has been found to be integral to the feeding process in this animal, along with a diuretic peptide(s). The large milkweed bug, Oncopeltus fasciatus, tends to feed in a more continuous and abstemious manner, and therefore may have different physiological requirements than the blood feeder. Unlike R. prolixus, O. fasciatus is lacking serotonin-like immunoreactive dorsal unpaired median neurons in the mesothoracic ganglionic mass, and lacks serotonin-like immunoreactive neurohaemal areas and processes on the abdominal nerves, integument, salivary glands, and anterior junction of the foregut and crop. The salivary glands and crop do, however, respond to serotonin with increased levels of cAMP, while the integument and Malpighian tubules do not. In addition, O. fasciatus Malpighian tubules respond to both O. fasciatus and R. prolixus partially purified CNS extracts, which are likely to contain any native diuretic peptides. Thus, while serotonin and diuretic peptides may be involved in tubule control in R. prolixus, the latter may be of greater importance in O. fasciatus.

  9. Ethnobotany of plants used as insecticides, repellents and ...

    African Journals Online (AJOL)

    An ethnobotanical study on plants used for the prevention and treatment of malaria was conducted to document the indigenous knowledge particularly associated with the use and conservation of anti-malarial, insecticide and insect repellent medicinal plants. In this study, five sampling sites were selected based on the ...

  10. Concentration of Plasmodium falciparum gametocytes in whole blood samples by magnetic cell sorting enhances parasite infection rates in mosquito feeding assays

    NARCIS (Netherlands)

    Reuling, I.J.; Stone, W.J.R.; Vegte-Bolmer, M. van de; Gemert, G.J.A. van; Siebelink-Stoter, R.; Graumans, W.; Lanke, K.H.; Bousema, T.; Sauerwein, R.W.

    2017-01-01

    BACKGROUND: Mosquito-feeding assays are important tools to guide the development and support the evaluation of transmission-blocking interventions. These functional bioassays measure the sporogonic development of gametocytes in blood-fed mosquitoes. Measuring the infectivity of low gametocyte

  11. Nutrition, feeding, and behavior of fish.

    Science.gov (United States)

    Lall, Santosh P; Tibbetts, Sean M

    2009-05-01

    Nutrition and feeding influence growth, reproduction, and health of fish and their response to physiologic and environmental stressors and pathogens. The basics of fish metabolism are similar to those of warm-blooded animals in that they involve food intake, digestion, absorption, and transport of nutrients to the various tissues. Fish, however, being the most primitive form of vertebrates, possess some distinguishing features which will be discussed. Unlike warm-blooded animals, which are homoeothermic, fish are poikilothermic, so their body temperature and metabolic rate depends on the water temperature and this has practical implications for the nutrition, feeding and health of fish. Several behavioral responses have been linked to methods of feeding, feeding habits, frequency of feeding, mechanisms of food detection, and food preferences. Fish are also unique among vertebrates in their ability to absorb minerals not only from their diets but also from water through their gills and skin.

  12. A fly in the ointment: evaluation of traditional use of plants to repel and kill blowfly larvae in fermented fish.

    Directory of Open Access Journals (Sweden)

    Hugo J de Boer

    Full Text Available INTRODUCTION: In rural areas in Laos, fly larvae infestations are common in fermenting fish. Blowflies (Chrysomya megacephala, Diptera: Calliphoridae are attracted to oviposit (and/or larviposit onto fermenting fish which results in infestations with fly larvae. Knowledge of traditional use of plants to repel larvae during the production of fermented fish is common and widespread in Lao PDR. RESEARCH QUESTIONS: How effective are the most salient species in repelling, and killing fly larvae in fermenting fish? MATERIAL AND METHODS: The three plant species most frequently reported to repel fly larvae during an ethnobotanical survey throughout Lao PDR were tested for repellence and larvicidal activity of fly larvae infesting fermented fish. The lethality and repellence of Tadehagi triquetrum (L. H. Ohashi (Fabaceae, Uraria crinita (L. Desv. ex DC. (Fabaceae and Bambusa multiplex (Lour. Raeusch. ex Schult. & Schult. f. (Poaceae were tested in an experimental design using fermenting fish in Vientiane, Lao PDR. RESULTS: The repellent effect of fresh material of T. triquetrum and U. crinita, and the larvicidal effect of fresh B. multiplex, is significantly more effective than that of dried material of the same species, and the total effect (repellence and larvicidal effect combined for each of the three species was significantly more effective for fresh than for dry material. Fresh material of T. triquetrum, U. crinita, or B. multiplex added on top of the fermenting fish repelled 50%, 54%, 37%, and killed 22%, 28%, and 40% of fly larvae. The total effect was not significantly different per species at 72%, 82%, and 77%, respectively. DISCUSSION AND CONCLUSIONS: The three most salient species are effective in repelling and killing fly larvae in the production of fermented fish, and may be essential to augment food safety during traditional fermentation in open jars.

  13. Water repellence assessment in humid mediterranean carbonated environments: influence of shrubland species

    Science.gov (United States)

    Oscar, Gonzalez-Pelayo; Vicente, Andreu; Luis, Rubio Jose; Carla Sofia, Ferreira; Dinis, Ferreira Antonio Jose

    2010-05-01

    The importance of natural or induced (fire) water repellence in terms of water redistribution in the soil profile, reduction in soil infiltration capacity and thus, in runoff magnification, is well established. Hydrophobicity has been identified around the world in different climatic conditions, land covers, soil and vegetation types. Regarding soil and vegetation, many studies are based on coarse acidic soils with pine forest, eucalyptus, deciduous trees, grassland, cropland, chaparral vegetation type, and lately in shrublands. However, few studies are related to shrubland in wet Mediterranean carbonated environments. This work is oriented to the study of soil water repellence in these environments by means of WDPT. The study was carried out in Podentes (Coimbra), central Portugal, on 4 ha of shrubland (mainly Quercus coccifera, Pistacia lentiscus and Arbutus unedo), developed on Umbric leptosol and Calcaric cambisol soil types (WRB). The WDPT was assessed depending on the shrubland type, slope orientation, soil depth (0-2 cm and 2-5 cm) and on different soil fractions (unedo. Soil water repellence decreased with depth. The studied shrubland species showed an increasing trend on the soil hydrophobicity persistence: A. unedo > Q. coccifera ≈ P. lentiscus; and depending on the orientation: NE > SW. Direct relationships were obtained between the soil organic matter content and the log WDPT on almost all the surface soil samples. The soil pH and carbonate content did not display correlation with soil water repellence. The different hydrophobic compounds generated by waxes and resins of the different shrubland types, which could be incorporated to the soil as binding agents, seem to be the explanation for the differences of the WDPT data. The patchy distribution of the vegetation rules the persistence of the natural soil water repellence, restraining water infiltration mainly by micropore flow, being then the soil hydrology controlled by the macropore flow, cracks

  14. Effect of water repellent preservatives and other wood treatments on restoration and durability of millwork

    Science.gov (United States)

    R. Sam Williams

    2001-01-01

    This report describes the long-term performance of painted window units that were placed outdoors near Madison, Wisconsin, in 1956. Covered in this report are the effects of the initial water repellent preservative (WRP) treatment during the first 6 years of exposure, a comparison of the water repellent effectiveness (WRE) ofthe WRP with the condition of the windows...

  15. Laboratory and field evaluation of spatial repellency with metofluthrin impregnated paper strip against mosquitoes in Lombok Island, Indonesia.

    OpenAIRE

    Kawada, Hitoshi; Maekawa, Yoshihide; Tsuda, yoshio; Takagi, Masahiro

    2004-01-01

    Spatial repellency of a new multilayer paper strip impregnated with metofluthrin, a newly synthesized pyrethroid, was evaluated in the laboratory and in the field at Kerandangan, Lombok Island, Indonesia,with the use of cow- and human-baited double nets. Spatial repellency was observed in both cow- and human-baited collections. Metofluthrin treatment reduced mosquito collection by >8O% during the lst 4 weeks.However, repellency seemed to reduce with the loss of metofluthrin by evaporation wit...

  16. Acaricidal and repellent activities of essential oil of Eucalyptus globulus against Dermanyssus gallinae (Acari: Mesostigmata

    Directory of Open Access Journals (Sweden)

    Dehghani-Samani Amir

    2015-07-01

    Full Text Available Introduction: By considering an increase in drug resistance against red mites, finding the nonchemical herbal acaricide against Dermanyssus gallinae (De Geer (Acari: Mesostigmata is necessary to kill them and to reduce the chemical resistance against chemical acaricides in this specie. Dermanyssus gallinae is a potential vector of the causal agent of several viral diseases such as Equine encephalitis and St. Louis encephalitis. It can be a vector of bacteria such as Salmonella spp., Mycobacterium spp. and Erysipelothrix rhusiopathiae. It is also known to cause itching dermatosis in humans. In this study acaricidal and repellent activities of essential oil of Eucalyptus globulus against Dermanyssus gallinae were studied. Methods: After extracting the essential oil, different concentrations of the plant extract were prepared. Then, acaricidal effect of different concentrations was tested on poultry red mite, Dermanyssus gallinae, by dropping 3-4 drops of essential oil on mites. Repellent activity of essential oil was tested by Y-tube olfactometer bioassay. After the test, total number of killed and repellent mites reported. Results: Concentration of 1:2 or 50% had more acaricidal effect on mites. Also essential oil of Eucalyptus globulus had repellent activity against red mites. Conclusion: This study showed that essential oil of Eucalyptus globulus had acaricidal and repellent activities against red mites. Hence it might be used as a herbal acaricide against it to kill and to reduce the chemical resistance in this specie.

  17. Broadband anti-reflective and water-repellent coatings on glass substrates for self-cleaning photovoltaic cells

    International Nuclear Information System (INIS)

    Li, Xiaoyu; He, Junhui; Liu, Weiyi

    2013-01-01

    Graphical abstract: High performance broadband antireflective and water-repellent coatings were fabricated on glass substrates, which can improve the short-circuit current of solar cells as much as 6.6% in comparison with glass substrates without the coatings. - Highlights: • Broadband anti-reflective and water-repellent coatings were fabricated. • Transmittance increased to 99.0%, significantly higher than that of commercial solar glasses. • The performance of standard solar cells with the AR coating was enhanced as much as 6.6%. - Abstract: High performance broadband antireflective (AR) and water-repellent coatings were fabricated on glass substrates by assembly of silica nanoparticles and polyelectrolytes via the layer-by-layer (LbL) assembly technique, followed by calcination and hydrophobic modification. A porous poly(diallyladimethylammonium chloride) (PDDA)/20 nm SiO 2 nanoparticles (S-20) multilayer coating with AR property was prepared first. The maximum transmittance is as high as 99.0%, while that of the glass substrate is only 91.3%. After calcination and hydrophobic modification, the coating became water-repellent while maintaining the good AR property. Such water-repellent AR coatings can improve the short-circuit current of solar cells as much as 6.6% in comparison with glass substrates without the coatings. Scanning electron microscopy (SEM) was used to observe the morphology and thickness of coatings. Transmission spectra and reflection spectra were characterized by UV–vis spectrophotometer. The surface wettability was studied by a contact angle/interface system

  18. How to repel hot water from a superhydrophobic surface?

    KAUST Repository

    Yu, Zhejun; Yang, Jieyi; Wan, Fang; Ge, Quan; Yang, Longlai; Ding, Zunliang; Yang, Dequan; Sacher, Edward R.; Isimjan, Tayirjan T.

    2014-01-01

    Superhydrophobic surfaces, with water contact angles greater than 150° and slide angles less than 10°, have attracted a great deal of attention due to their self-cleaning ability and excellent water-repellency. It is commonly accepted that a

  19. Application of minidisk infiltrometer to estimate soil water repellency

    Science.gov (United States)

    Alagna, Vincenzo; Iovino, Massimo; Bagarello, Vincenzo; Mataix-Solera, Jorge; Lichner, Ľubomír

    2016-04-01

    Soil water repellency (SWR) reduces affinity of soils to water resulting in detrimental implication for plants growth as well as for hydrological processes. During the last decades, it has become clear that SWR is much more widespread than formerly thought, having been reported for a wide variety of soils, land uses and climatic conditions. The repellency index (RI), based on soil-water to soil-ethanol sorptivity ratio, was proposed to characterize subcritical SWR that is the situation where a low degree of repellency impedes infiltration but does not prevent it. The minidisk infiltrometer allows adequate field assessment of RI inherently scaled to account for soil physical properties other than hydrophobicity (e.g., the volume, connectivity and the geometry of pores) that directly influence the hydrological processes. There are however some issues that still need consideration. For example, use of a fixed time for both water and ethanol sorptivity estimation may lead to inaccurate RI values given that water infiltration could be negligible whereas ethanol sorptivity could be overestimated due to influence of gravity and lateral diffusion that rapidly come into play when the infiltration process is very fast. Moreover, water and ethanol sorptivity values need to be determined at different infiltration sites thus implying that a large number of replicated runs should be carried out to obtain a reliable estimate of RI for a given area. Minidisk infiltrometer tests, conducted under different initial soil moisture and management conditions in the experimental sites of Ciavolo, Trapani (Italy) and Javea, Alicante (East Spain), were used to investigate the best applicative procedure to estimate RI. In particular, different techniques to estimate the water, Sw, and ethanol, Se, sorptivities were compared including i) a fixed 1-min time interval, ii) the slope of early-time 1D infiltration equation and iii) the two-term transient 3D infiltration equation that explicitly

  20. CO2 response to rewetting of hydrophobic soils - Can soil water repellency inhibit the 'Birch effect'?

    Science.gov (United States)

    Sanchez-Garcia, Carmen; Urbanek, Emilia; Doerr, Stefan

    2017-04-01

    Rewetting of dry soils is known to cause a short-term CO2 pulse commonly known as the 'Birch effect'. The displacement of CO2 with water during the process of wetting has been recognised as one of the sources of this pulse. The 'Birch effect' has been extensively observed in many soils, but some studies report a lack of such phenomenon, suggesting soil water repellency (SWR) as a potential cause. Water infiltration in water repellent soils can be severely restricted, causing overland flow or increased preferential flow, resulting in only a small proportion of soil pores being filled with water and therefore small gas-water replacement during wetting. Despite the suggestions of a different response of CO2 fluxes to wetting under hydrophobic conditions, this theory has never been tested. The aim of this study is to test the hypothesis that CO2 pulse does not occur during rewetting of water repellent soils. Dry homogeneous soils at water-repellent and wettable status have been rewetted with different amounts of water. CO2 flux as a response to wetting has been continuously measured with the CO2 flux analyser. Delays in infiltration and non-uniform heterogeneous water flow were observed in water repellent soils, causing an altered response in the CO2 pulse in comparison to typically observed 'Birch effect' in wettable systems. The main conclusion from the study is that water repellency not only affects water relations in soil, but has also an impact on greenhouse gas production and transport and therefore should be included as an important parameter during the sites monitoring and modelling of gas fluxes.

  1. The formulation of the essential oil of Piper aduncum Linnaeus (Piperales: Piperaceae) increases its efficacy as an insect repellent.

    Science.gov (United States)

    Mamood, S N H; Hidayatulfathi, O; Budin, S B; Ahmad Rohi, G; Zulfakar, M H

    2017-02-01

    The essential oil (EO) of Piper aduncum Linnaeus, known as 'sireh lada' to locals Malaysian, has the potential to be used as an alternative to synthetic insect repellents such as N,N-diethyl-meta-toluamide. However, the EO's efficacy as a repellent decreases after application due to the high volatility of its active ingredients. A number of studies have showed that optimizing the formulation of plant-based EOs can improve their efficacy as repellents. The present study sought to evaluate the effectiveness of 10% P. aduncum EO in ethanol and in three different semisolid formulations: ointment, cream and gel. These formulations were tested on Aedes aegypti under laboratory conditions. Each formulation was applied to the subject's hands, which were then inserted into a cage containing 25 nulliparous A. aegypti. The number of mosquitoes landing on or biting each subject's hand was recorded, and the repellency percentage, landing/biting percentage and protection time for each of the formulations were compared. There were no statistically significant differences between the semisolid EO formulations with regards to the repellency percentage and the landing/biting percentage at 4 h post-application. All three semisolid EO formulations were able to repel >65% of the A. aegypti at 4 h post-application. The EO ointment formulation provided a protection time (182.5 ± 16.01 min) that was statistically significantly longer than that associated with the EO gel formulation (97.5 ± 14.93 min). Meanwhile, the EO cream formulation provided a protection time of 162.5 ± 6.29 min. As the EO cream and ointment formulations displayed better repellent properties than the EO gel formulation, they appear to be the most promising P. aduncum EO formulations to be developed and commercialized as alternatives to synthetic repellents.

  2. Laboratory and field evaluation of spatial repellency with metofluthrin-impregnated paper strip against mosquitoes in Lombok Island, Indonesia.

    Science.gov (United States)

    Kawada, Hitoshi; Maekawa, Yoshihide; Tsuda, Yoshio; Takagi, Masahiro

    2004-09-01

    Spatial repellency of a new multilayer paper strip impregnated with metofluthrin, a newly synthesized pyrethroid, was evaluated in the laboratory and in the field at Kerandangan, Lombok Island, Indonesia, with the use of cow- and human-baited double nets. Spatial repellency was observed in both cow- and human-baited collections. Metofluthrin treatment reduced mosquito collection by >80% during the 1st 4 weeks. However, repellency seemed to reduce with the loss of metofluthrin by evaporation within 6 wk after treatment.

  3. Effect of humic-plant feed preparations on biochemical blood parameters of laying hens in deep litter housing system.

    Science.gov (United States)

    Bubel, F; Dobrzański, Z; Gaweł, A; Pogoda-Sewerniak, K; Grela, E R

    2015-01-01

    An influence of various humic-plant feed additives based on some herbs (nettle, chamomile, yarrow, perforatum), lucerne and humic materials on biochemical indices of Lohmann Brown (LB) layers blood plasma was estimated. Hens were housed in deep litter system, 20 birds in a group. Four groups were formed: control (C - standard feeding), and experimental, supplemented with prepara- tions: E-1 herbal-humic, E-2 humic-herbal and E-3--humic-lucerne. Hens were placed in the pens on the 16th week of life, addition of preparations with standard food mixture started at the 22nd wk and lasted until 66th wk of life. Blood for analyses was collected four times in the following periods: 27, 37, 54 and 65th wk of life. The applied humic-plant preparations to a limited degree affected the values of examined biochemical parameters in serum: total protein (TP), albumins (Albs), glucose (Glu), urea, triacylglycerols (TAG), total cholesterol (TCh), alanine aminotransferase (ALT), aspartate aminot- ransferase (AST) and alkaline phosphatase (ALP). It is difficult to determine based on these study, which preparation is one the most active biologically, however is seems that humic-lucerne prepara- tion affected the examined blood parameters to the highest degree. The reference values ranges in hens blood serum LB hens were proposed for: TP (43-65 g/l), Albs (15-22 g/l), urea (0.5-1.2 mmol/l), Glu 10-15 mmol/l), TCh (2.2-4.5 mmol/l), TAG (10-24 mmol/l), AST (4-12 U/l), ALT (150-280 mmol/l) and ALP (190-350 U/l).

  4. Insecticidal and Repellent Properties of Subtropical Plant Extracts Against Pulse Beetle, Callosobruchus chinensis

    Directory of Open Access Journals (Sweden)

    H.T. AI Lawati

    2002-01-01

    Full Text Available Extracts of eight plants local to Oman, namely Qarat (Acacia nilotica, Mustafal (Annona squamosa, Shereesh (Azadirachta indica, Luban (Boswellia sacra, Kheshkhash (Crotolaria juncea, Zebrot (Jatropha dhofarica Yas, (Myrtus communis and Suwwad (Suaeda aegyptiaca were prepared by steeping shaded dried leaf/ seed powder of each plant in water and solvent (methanol or ethanol. The extracts were tested for their insecticidal and repellent properties against the pulse beetles, Callosobruchus chinensis. The extracts from the seeds of A. squamosa recorded l00% mortality of beetles within twenty and four hours of their exposure to methanol and ethanol extracts, respectively. The other extracts that caused high mortality were from A. nilotica, C. juncea, M. communis and S. aegzptiaca in methanol and B. sacra, J. dhofarica, S. aegptiaca and commercial neem in ethanol. Extracts of M. communis in methanol were highly repellent to the beetles compared to other extracts. Legume seeds treated with extracts of A. squamosa were not repellent, rather the beetles were attracted to them.

  5. Mortality and repellent effects of microbial pathogens on Coptotermes formosanus (Isoptera: Rhinotermitidae

    Directory of Open Access Journals (Sweden)

    Wright Maureen S

    2012-12-01

    Full Text Available Abstract Background Two entomopathogenic fungi, Isaria fumosorosea and Metarhizium anisopliae, and one bacterium, Bacillus thuringiensis, were tested for their ability to cause mortality of Formosan subterranean termites (FST, Coptotermes formosanus (Shiraki, after liquid exposure, and for their lack of propensity to repel FST. Results The fungus Isaria fumosorosea at 108 spores/ml caused 72.5% mortality on day 7, significantly higher than the control and 106 spores/ml treatment. On day 14, the 106 and 108 concentrations caused 38.8% and 92.5% mortality, respectively, significantly higher than the control. On day 21, 82.5% and 100% of the termites were killed by the 106 and 108 treatments, respectively. I. fumosorosea did not repel termites at 106 nor 108 spores/g in sand, soil or sawdust. The fungus Metarhizium anisopliae at 108 spores/ml caused 57.5% mortality on day 7, 77.5% mortality on day 14 and 100% mortality on day 21. Conclusions On all three days the rate of mortality was significantly higher than that of the control and 106 spores/ml treatment with I. fumosorosea. Neither I. fumosorosea nor M. anisopliae caused repellency of FST in sand, soil or sawdust. The bacterium Bacillus thuringiensis did not cause significant mortality on days 7, 14 or 21. When termites were exposed to cells of B. thuringiensis in sawdust and when termites were exposed to a mixture of spores and cells in sand, a significantly higher number remained in the control tubes. Repellency was not seen with B. thuringiensis spores alone, nor with the above treatments in the other substrates.

  6. Experimental use of two standard tick collection methods to evaluate the relative effectiveness of several plant-derived and synthetic repellents against Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae).

    Science.gov (United States)

    Schulze, Terry L; Jordan, Robert A; Dolan, Marc C

    2011-12-01

    We used two standard tick collection methods to test the relative effectiveness of two natural product compounds (nootkatone and carvacrol, classified as an eremophilene sesquiterpene and a monoterpene, respectively, that are derived from botanical sources) with commercially-available plant-derived (EcoSMART Organic Insect Repellent, comprised of plant essential oils) and permethrin-based (Repel Permanone) repellents against Ixodes scapularis Say and Amblyomma americanum (L.). Cloth drags were equally effective in sampling both species of host-seeking nymphs, whereas CO, traps attracted primarily A. americanum. All four repellents performed well on drags, with nootkatone and Permanone Repel (100% repelled through 14 d) slightly more effective than carvacrol and EcoSMART (90.7% and 97.7% repelled at 14 d, respectively) at repelling I. scapularis nymphs. Although the same trend in percent repellency was noted in the CO2 trap trial against both A. americanum nymphs and adults, EcoSMART outperformed Permanone in repelling A. Americanum nymphs after 14 d in the drag trial. Generally, the effectiveness of all repellents tested declined over time. The use of tick drags and CO2 traps was rapid, inexpensive, and easy to use in determining the relative effectiveness of repellents in the field.

  7. Effect of feeding glucose, fructose, and inulin on blood glucose and insulin concentrations in normal ponies and those predisposed to laminitis.

    Science.gov (United States)

    Borer, K E; Bailey, S R; Menzies-Gow, N J; Harris, P A; Elliott, J

    2012-09-01

    Identification of ponies (Equus caballus) at increased risk of pasture-associated laminitis would aid in the prevention of the disease. Insulin resistance has been associated with laminitis and could be used to identify susceptible individuals. Insulin resistance may be diagnosed by feeding supplementary water-soluble carbohydrate (WSC) and measuring blood glucose and insulin concentrations. The aim of this study was to assess the glycemic and insulinemic responses of 7 normal (NP) and 5 previously laminitic (PLP), mixed breed, native UK ponies fed glucose, fructose, and inulin [1 g/(kg·d) for 3 d] or no supplementary WSC (control) in spring and fall after a 7-d adaptation to a pasture or hay diet. Blood samples were taken for 12 h after feeding on each day, and baseline and peak concentrations and area under the curve (AUC) for glucose and insulin were recorded. Linear mixed models were used for statistical analysis. Differences between PLP and NP groups were most marked after glucose feeding with differences in peak glucose (P = 0.02) and peak insulin (P = 0.016) concentrations. Season and diet adaptation also affected results. Peak concentrations of glucose and insulin occurred 2 to 4 h after WSC feeding. Peak insulin concentration was greater and more variable in fall, particularly in PLP adapted to fall pasture. Baseline glucose and insulin concentrations varied between individuals and with season and diet adaptation but were not greater in PLP than NP. Insulin AUC was greater in PLP than NP after feeding both glucose and fructose (P = 0.017), but there were no differences between PLP and NP in glucose AUC. Glycemic and insulinemic changes were less (P ≤ 0.05) after feeding fructose than glucose, although differences between PLP and NP were still evident. Minimal changes in glucose and insulin concentrations occurred after inulin feeding. Measurement of peak insulin 2 h after feeding of a single dose of glucose (1 g/kg) may be a simple and practical way to

  8. Effect of feeding different levels of Azolla pinnata on blood biochemicals, hematology and immunocompetence traits of Chabro chicken.

    Science.gov (United States)

    Mishra, Deepesh Bharat; Roy, Debashis; Kumar, Vinod; Bhattacharyya, Amitav; Kumar, Muneendra; Kushwaha, Raju; Vaswani, Shalini

    2016-02-01

    The present study was conducted to see the effect of feeding different levels of Azolla meal on blood biochemicals, hematology and immunocompetence traits of Chabro chicken. The study was conducted on 160 Chabro chicks, which were randomly divided into four treatment groups each with four replicates of 10 birds. The first treatment (T1) served as a control in which basal diets was offered without Azolla supplementation while in T2, T3, and T4 groups, basal diet was replaced with Azolla meal at 5%, 7.5%, and 10% levels, respectively. A feeding trial was conducted upto 8 weeks. At the last week of trial, blood samples were collected randomly from one bird of each replicate and plasma was separated to estimate certain biochemical parameters, some blood metabolites, minerals and enzymes like alanine aminotransferase and aspartate aminotransferase (AST). Hematological parameters such as hemoglobin, packed cell volume, total leukocytes count and differential leukocytes count were estimated in fresh blood just after collection. The humoral immune response was measured against sheep red blood cells,and cell-mediated immune response was measured against phyto hemagglutinin lectin from Phaseolus vulgaris (PHA-P). The study showed that hematological profile of the Chabro bird was not affected by any treatment except heterophil and lymphocyte which was found higher in T2 and T3 groups and eosinophil was found higher in a T3 group than control. Blood glucose, creatinine, cholesterol, total protein, albumin, uric acid, and triglycerides were found similar in all the groups and within the normal values for broiler chicken. Liver enzymes and macro mineral content in blood were found similar in all the treatment groups and within normal physiological range. Although AST was found higher in 10% replacement group than control, the value was within normal range for broiler chicken. Although antibody titer was found similar in all the experimental groups in the present study, cell

  9. N,N-diethyl phenylacetamide (DEPA): A safe and effective repellent for personal protection against hematophagous arthropods.

    Science.gov (United States)

    Kalyanasundaram, Muthuswami; Mathew, Nisha

    2006-05-01

    Repellents play an important role in protecting humans from the bites of insect pests. An effective and safe repellent will be useful in reducing human-vector contact and thereby help in the interruption of vector borne disease transmission. Because of the unavailability of m-toluic acid in India for the manufacture of N,N-diethyl m-toluamide (DEET), there is a need to develop an alternate effective and safe insect repellent. In total, 120 substituted amides were synthesized and tested for repellency at 1.0 mg/cm2 under laboratory conditions. Among these amides, N,N-diethyl phenylacetamide (DEPA), applied at 1.0 mg/cm2 in different oil bases, was found to exhibit promising repellency (6-8 h) in the laboratory when tested against Aedes aegypti (L.) The repellent DEPA was evaluated on army personnel in comparison with dimethylphthalate (DMP) and DEET against mosquitoes, black flies, and land leeches under field condition in the North-East Frontier area of India. Both DEPA and DEET displayed broad-spectrum repellency. DEPA was more effective than DMP against all test organisms. However, no significant difference was noticed between DEPA and DEET for repellency at 0.25 and 0.5 mg/cm2 against black flies and mosquitoes. DMP was the least effective among the three compounds in the field studies. The relative potency of DEPA in comparison with DEET and DMP for repellency against Phlebotomine sand flies also was determined. At 0.1 mg/cm2, both DEPA and DEET were found to be equally effective with a protection time from 4.37 +/- 0.08 to 4.45 +/- 0.15 h. Both compounds were significantly more effective than DMP. At 0.2 mg/cm2, DEPA and DEET provided protection times of 6.52 +/- 0.08 and 7.15 +/- 0.15 h, respectively. DEPA was formulated into a vanishing cream, a pharmacologically safe polymer-based liquid, and a liposphere lotion. The vanishing cream and the two-polymer liquid formulations enhanced protection times from 4.4 to 6.5 and 7.13 h, respectively, compared with an

  10. Octanoic acid confers to royal jelly varroa-repellent properties

    Science.gov (United States)

    Nazzi, Francesco; Bortolomeazzi, Renzo; Della Vedova, Giorgio; Del Piccolo, Fabio; Annoscia, Desiderato; Milani, Norberto

    2009-02-01

    The mite Varroa destructor Anderson & Trueman is a parasite of the honeybee Apis mellifera L. and represents a major threat for apiculture in the Western world. Reproduction takes place only inside bee brood cells that are invaded just before sealing; drone cells are preferred over worker cells, whereas queen cells are not normally invaded. Lower incidence of mites in queen cells is at least partly due to the deterrent activity of royal jelly. In this study, the repellent properties of royal jelly were investigated using a lab bioassay. Chemical analysis showed that octanoic acid is a major volatile component of royal jelly; by contrast, the concentration is much lower in drone and worker larval food. Bioassays, carried out under lab conditions, demonstrated that octanoic acid is repellent to the mite. Field studies in bee colonies confirmed that the compound may interfere with the process of cell invasion by the mite.

  11. Bioassay-guided investigation of two monarda essential oils as repellents of yellow fever mosquito Aedes aegypti

    Science.gov (United States)

    As part of an ongoing research program to identify active mosquito repellents, Monarda bradburiana Beck and M. fistulosa L. essential oils showed potent repellents with minimum effective dosages (MED) of 0.055 ± 0.036 and 0.078 ± 0.027 mg/cm2, respectively, compared to reference standard N,N-diethyl...

  12. [Field efficacy of repellent formulation containing para-menthane-3,8-diol and lemongrass against Culicoides pachymerus (Diptera: Ceratopogonidae) in Colombia].

    Science.gov (United States)

    Santamaría, Erika; Cabrera, Olga Lucía; Zipa, Yaneth; Pardo, Raúl Hernando

    2012-09-01

    Culicoides pachymerus is a major pest species for the inhabitants of the western Boyacá province of Colombia. The effect of a repellent lotion based on p-menthane-3,8-diol (16%) and lemongrass oil (2%) was evaluated against the bites of C. pachymerus. The repellent lotion was compared simultaneously with a control (no treatment) by human landing catches of C. pachymerus on the forearms of paired volunteers situated near human dwellings. Protection percentage and protection time for 3 to 6 h after repellent application was calculated. The test was repeated ten times. Only two females of C. pachymerus were collected on arms with the repellent treatment. In contrast, the mean biting rate in the untreated control was 47.7 midges/person/10 min. Mean protection percentage of the repellent was 100% up to 4 h and 99.5% up to 5 h. Protection time was 332.2 and 338.2 min in the two replicates where bites of C. pachymerus were confirmed. In the remaining eight replicates protection time exceeded the test duration. The repellent showed high efficacy against C. pachymerus, up to 5 h post-application.

  13. Sex specific molecular responses of quick-to-court protein in Indian malarial vector Anopheles culicifacies: conflict of mating versus blood feeding behaviour

    Directory of Open Access Journals (Sweden)

    Tanwee Das De

    2017-07-01

    Full Text Available Understanding the molecular basis of mosquito behavioural complexity plays a central role in designing novel molecular tools to fight against their vector-borne diseases. Although the olfactory system plays an important role in guiding and managing many behavioural responses including feeding and mating, but the sex-specific regulation of olfactory responses remain poorly investigated. From our ongoing transcriptomic data annotation of olfactory tissue of blood fed adult female An. culicifacies mosquitoes; we have identified a 383 bp long unique transcript encoding a Drosophila homolog of the quick-to-court protein. Previously this was shown to regulate courtship behaviour in adult male Drosophila. A comprehensive in silico analysis of the quick-to-court (qtc gene of An. culicifacies (Ac-qtc predicts a 1536 bp single copy gene encoding 511 amino acid protein, having a high degree of conservation with other insect homologs. The age-dependent increased expression of putative Ac-qtc correlated with the maturation of the olfactory system, necessary to meet the sex-specific conflicting demand of mating (mate finding versus host-seeking behavioural responses. Sixteen to eighteen hours of starvation did not alter Ac-qtc expression in both sexes, however, blood feeding significantly modulated its response in the adult female mosquitoes, confirming that it may not be involved in sugar feeding associated behavioural regulation. Finally, a dual behavioural and molecular assay indicated that natural dysregulation of Ac-qtc in the late evening might promote the mating events for successful insemination. We hypothesize that Ac-qtc may play a unique role to regulate the sex-specific conflicting demand of mosquito courtship behaviour versus blood feeding behaviour in the adult female mosquitoes. Further elucidation of this molecular mechanism may provide further information to evaluate Ac-qtc as a key molecular target for mosquito-borne disease management.

  14. The effect of photoperiod on life history and blood-feeding activity in Aedes albopictus and Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Costanzo, K S; Schelble, S; Jerz, K; Keenan, M

    2015-06-01

    Several studies have examined how climatic variables such as temperature and precipitation may affect life history traits in mosquitoes that are important to disease transmission. Despite its importance as a seasonal cue in nature, studies investigating the influence of photoperiod on such traits are relatively few. This study aims to investigate how photoperiod alters life history traits, survival, and blood-feeding activity in Aedes albopictus (Skuse) and Aedes aegypti (Linnaeus). We performed three experiments that tested the effects of day length on female survival, development time, adult size, fecundity, adult life span, and propensity to blood feed in Ae. albopictus and Ae. aegypti. Each experiment had three photoperiod treatments: 1) short-day (10L:14D), 2) control (12L:12D), and 3) long-day (14L:10D). Aedes albopictus adult females were consistently larger in size when reared in short-day conditions. Aedes aegypti adult females from short-day treatments lived longer and were more likely to take a blood meal compared to other treatments. We discuss how species-specific responses may reflect alternative strategies evolved to increase survival during unfavorable conditions. We review the potential impacts of these responses on seasonal transmission patterns, such as potentially increasing vectorial capacity of Ae. aegypti during periods of shorter day lengths. © 2015 The Society for Vector Ecology.

  15. Laser removal of water repellent treatments on limestone

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Heras, Miguel; Alvarez de Buergo, Monica; Rebollar, Esther; Oujja, Mohamed; Castillejo, Marta; Fort, Rafael

    2003-12-15

    Protective and water repellent treatments are applied on stone materials used on buildings or sculptures of artistic value to reduce water intrusion without limiting the natural permeability to water vapour of the material. The effect of the wavelength associated with the laser removal of two water repellent treatments applied on limestone, Paraloid B-72, a copolymer of methyl acrylate and ethyl methacrylate, and Tegosivin HL-100, a modified polysiloxane resin, was investigated by using the four harmonics of a Q-switched Nd:YAG laser (1064, 532, 355 and 266 nm). The modifications induced on the surface of limestone samples by laser irradiation were studied using colorimetry, roughness measurements and scanning electron microscopy (SEM). The removal of the treatments was found to be dependent on the laser irradiation conditions and on the characteristics of the coatings. The fundamental laser radiation was effective in removing both treatments, but thermal alteration processes were induced on the constituent calcite crystals. The best results were obtained by irradiation in the near UV at 355 nm.

  16. A new approach to the problem of chaotic repellers

    International Nuclear Information System (INIS)

    Szepfalusy, P.; Tel, T.

    1986-05-01

    It is shown that a smooth stationary distribution can be derived for 'coarse grained' repellers by compensating the local escape. This provides a convenient framework to investigate statistical properties of long chaotic transients. Furthermore, the procedure yields a powerful tool for calculating fractal dimensions. (author)

  17. Extreme Wetting-Resistant Multiscale Nano-/Microstructured Surfaces for Viscoelastic Liquid Repellence

    Directory of Open Access Journals (Sweden)

    Aoythip Chunglok

    2016-01-01

    Full Text Available We demonstrate exceptional wetting-resistant surfaces capable of repelling low surface tension, non-Newtonian, and highly viscoelastic liquids. Theoretical analysis and experimental result confirm that a higher level of multiscale roughness topography composed of at least three structural length scales, ranging from nanometer to supermicron sizes, is crucial for the reduction of liquid-solid adhesion hysteresis. With Cassie-Baxter nonwetting state satisfied at all roughness length scales, the surface has been proven to effectively repel even highly adhesive liquid. Practically, this high-level hierarchical structure can be achieved through fractal-like structures of silica aggregates induced by siloxane oligomer interparticle bridges. The induced aggregation and surface functionalization of the silica particles can be performed simultaneously within a single reaction step, by utilizing trifunctional fluoroalkylsilane precursors that largely form a disordered fluoroalkylsiloxane grafting layer under the presence of sufficient native moisture preadsorbed at the silica surface. Spray-coating deposition of a particle surface layer on a precoated primer layer ensures facile processability and scalability of the fabrication method. The resulting low-surface-energy multiscale roughness exhibits outstanding liquid repellent properties, generating equivalent lotus effect for highly viscous and adhesive natural latex concentrate, with apparent contact angles greater than 160°, and very small roll-off angles of less than 3°.

  18. Mediation of deet repellency in mosquitoes (Diptera: Culicidae) by species, age, and parity.

    Science.gov (United States)

    Barnard, D R

    1998-05-01

    Laboratory bioassays assessed differences in the protection time provided by the repellent deet (N,N-diethyl-3-methylbenzamide) against 5-d-old nulliparous and 10-, 15-, and 20-d-old nulliparous and parous female Aedes aegypti (L.), Anopheles albimanus (Weidemann), and Anopheles quadrimaculatus Say sensu lato. Mean protection time was shortest against An. albimanus (1.6 h) and An. quadrimaculatus (1.5 h) and longest against Ae. aegypti (6.5 h), but was not significantly influenced by mosquito age or parity. Mean percentage of biting at repellent failure time was highest in An. albimanus (14.2%), followed by An. quadrimaculatus (7.0%) and Ae. aegypti (2.9%), was higher in parous females (10.8%) than in nulliparous females (5.9%), and was highest overall (35%) in 20-d-old parous An. albimanus. Interaction between mosquito species and parity and between parity and age factors, respectively, resulted from a significant decrease in percentage of biting by parous An. quadrimaculatus compared with other females, and a significant increase in biting by 20-d-old parous females compared with other females. The main finding of this study is that repellent protection time is unaffected by parity; this is important because parous mosquitoes are the primary target of personal-protection measures in disease-endemic areas. When repellent failure did occur, there was a higher risk of bite by old, parous An. albimanus than for any other species, age, or parity grouping of females.

  19. Robust Manipulations of Pest Insect Behavior Using Repellents and Practical Application for Integrated Pest Management.

    Science.gov (United States)

    Wallingford, Anna K; Cha, Dong H; Linn, Charles E; Wolfin, Michael S; Loeb, Gregory M

    2017-10-01

    In agricultural settings, examples of effective control strategies using repellent chemicals in integrated pest management (IPM) are relatively scarce compared to those using attractants. This may be partly due to a poor understanding of how repellents affect insect behavior once they are deployed. Here we attempt to identify potential hallmarks of repellent stimuli that are robust enough for practical use in the field. We explore the literature for success stories using repellents in IPM and we investigate the mechanisms of repellency for two chemical oviposition deterrents for controlling Drosophila suzukii Matsumura, a serious pest of small fruit crops. Drosophila suzukii causes injury by laying her eggs in ripening fruit and resulting larvae make fruit unmarketable. In caged choice tests, reduced oviposition was observed in red raspberry fruit treated with volatile 1-octen-3-ol and geosmin at two initial concentrations (10% and 1%) compared to untreated controls. We used video monitoring to observe fly behavior in these caged choice tests and investigate the mode of action for deterrence through the entire behavioral repertoire leading to oviposition. We observed fewer visitors and more time elapsed before flies first landed on 1-octen-3-ol-treated fruits than control fruits and concluded that this odor primarily inhibits behaviors that occur before D. suzukii comes in contact with a potential oviposition substrate (precontact). We observed some qualitative differences in precontact behavior of flies around geosmin-treated fruits; however, we concluded that this odor primarily inhibits behaviors that occur after D. suzukii comes in contact with treated fruits (postcontact). Field trials found reduced oviposition in red raspberry treated with 1-octen-3-ol and a combination of 1-octen-3-ol and geosmin, but no effect of geosmin alone. Recommendations for further study of repellents for practical use in the field are discussed. © The Authors 2017. Published by

  20. Thermal properties and water repellency of cotton fabric prepared through sol-gel method

    Directory of Open Access Journals (Sweden)

    Gu Jia-Li

    2016-01-01

    Full Text Available Cotton fabrics were treated by one-step sol-gel method. The pure silica hydrosol and phosphorus-doped hydrosol were prepared with the addition of a hydrophobic hexadecyltrimethoxysilane to decrease the surface energy of cotton fabric. The thermal properties and water repellency of treated cotton fabric were characterized by thermo-gravimetric analysis, micro combustion, limiting oxygen index, and contact angle measurement. The results showed that cotton fabric treated by phosphorus-doped silica hydrosol had excellent flame retardance, and the water repellence was apparently improved with the addition of hexadecyltrimethoxysilane.

  1. Soil water repellency and its hydro-geomorphological consequences

    Czech Academy of Sciences Publication Activity Database

    Lichner, Ľ.; Babejová, N.; Šír, Miloslav; Tesař, Miroslav

    2003-01-01

    Roč. 2, č. 2 (2003), s. 1-7 ISSN 1336-1120 R&D Projects: GA AV ČR IAA3060001 Grant - others:Slovac Scientific Grant Agency(SK) 2/3032/23; Science and Technology Assistance Agency(SK) APVT-51-006502 Institutional research plan: CEZ:AV0Z2060917 Keywords : hydrophobicity * water repellency * soil Subject RIV: DA - Hydrology ; Limnology

  2. Substitution of wheat bran by corn gluten feed without steep water in cats feed

    Directory of Open Access Journals (Sweden)

    Lívia Geraldi Ferreira

    Full Text Available ABSTRACT: This study aimed to evaluate the effects of substituting wheat bran (WB by corn gluten feed without steep water (CGF in cats feeds regarding the nutritional value of the diet, stool characteristics, time of food passage through the gastrointestinal tract (GIT, intestinal gas production and concentrations of short chain fatty acids (SCFA in blood and faeces. Twenty eight cats were distributed in a randomized block design with four treatments (0, 2.6, 5.3 or 8.0% CGF, based on dry matter, substituting for WB and seven replicates. Substitution of WB by CGF decreased (P0.05 the digestibility of other nutrients and apparent metabolizable energy. There was also no effect (P>0.05 on faeces moisture, faecal pH and score, food transit time in the GIT, intestinal gas area and SCFA concentrations in faeces, while blood concentrations of propionate were influenced differently by the different feeds and sampling times (P<0.05. Thus replacement of up to 8% of WB by CGF may be done safely in cats feed.

  3. The role of repellents and hydrophobins in Ustilago maydis

    NARCIS (Netherlands)

    Teertstra, W.R.

    2009-01-01

    Ustilago maydis is an important model organism to study fungal pathogenicity. U. maydis can grow yeast-like and filamentous. In the latter form this fungus infects maize. In my Thesis the expression and function of hydrophobins and repellents of U. maydis were studied. Hydrophobins are produced by

  4. ESTIMATION OF AFLATOXIN B1 IN FEED INGREDIENTS AND COMPOUND POULTRY FEEDS

    Directory of Open Access Journals (Sweden)

    Bashir Mahmood Bhatti, Tanzeela Talat and Rozina Sardar

    2001-02-01

    Full Text Available A total of 3230 samples of feed ingredients of vegetable and animal origin and commercially available compound poultry feed received over a period of 5 years at Feed Testing Laboratory of the Institute were tested for Aflatoxin B1 contents (ppb . In all feed ingredients and compound feed stuffs, minimum level of aflatoxin B1 was 13 ppb and maximum level was found to be 78 ppb. No correlation of aflatoxin levels with month of collection of the year which are subject to variation in temperature and humidity could be detected. Mean values of aflatoxin concentration in feed stuffs such as rice, rice polish, wheat bran, wheat bread, maize, fish meal, blood meal, bone meal, guar meal, corn gluten 30%, corn gluten 60%, sun flower meal, soyabean meal and cotton seed meal were found to be higher than safe level of 20 ppb recommended by FDA.

  5. Influence of Long-term Application of Feedlot Manure Amendments on Water Repellency of a Clay Loam Soil.

    Science.gov (United States)

    Miller, Jim J; Beasley, Bruce W; Hazendonk, Paul; Drury, Craig F; Chanasyk, David S

    2017-05-01

    Long-term application of feedlot manure to cropland may increase the quantity of soil organic carbon (C) and change its quality, which may influence soil water repellency. The objective was to determine the influence of feedlot manure type (stockpiled vs. composted), bedding material (straw [ST] vs. woodchips [WD]), and application rate (13, 39, or 77 Mg ha) on repellency of a clay loam soil after 17 annual applications. The repellency was determined on all 14 treatments using the water repellency index ( index), the water drop penetration time (WDPT) method, and molarity of ethanol (MED) test. The C composition of particulate organic matter in soil of five selected treatments after 16 annual applications was also determined using C nuclear magnetic resonance-direct polarization with magic-angle spinning (NMR-DPMAS). Manure type had no significant ( > 0.05) effect on index and WDPT, and MED classification was similar. Mean index and WDPT values were significantly greater and MED classification more hydrophobic for WD than ST. Application rate had no effect on the index, but WDPT was significantly greater and MED classification more hydrophobic with increasing application rate. Strong ( > 0.7) but nonsignificant positive correlations were found between index and WDPT versus hydrophobic (alkyl + aromatic) C, lignin at 74 ppm (O-alkyl), and unspecified aromatic compounds at 144 ppm. Specific aromatic compounds also contributed more to repellency than alkyl, O-alkyl, and carbonyl compounds. Overall, all three methods consistently showed that repellency was greater for WD- than ST-amended clay loam soil, but manure type had no effect. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  6. Application of minidisk infiltrometer to estimate water repellency in Mediterranean pine forest soils

    Directory of Open Access Journals (Sweden)

    Alagna Vincenzo

    2017-09-01

    Full Text Available Assessment of soil water repellency (SWR was conducted in the decomposed organic floor layer (duff and in the mineral soil layer of two Mediterranean pine forests, one in Italy and the other in Spain, by the widely-used water drop penetration time (WDPT test and alternative indices derived from infiltration experiments carried out by the minidisk infiltrometer (MDI. In particular, the repellency index (RI was calculated as the adjusted ratio between ethanol and water soil sorptivities whereas the water repellency cessation time (WRCT and the specifically proposed modified repellency index (RIm were derived from the hydrophobic and wettable stages of a single water infiltration experiment. Time evolution of SWR and vegetation cover influence was also investigated at the Italian site. All indices unanimously detected severe SWR conditions in the duff of the pine forests. The mineral subsoils in the two forests showed different wettability and the clay-loam subsoil at Ciavolo forest was hydrophobic even if characterized by organic matter (OM content similar to the wettable soil of an adjacent glade. It was therefore assumed that the composition rather than the total amount of OM influenced SWR. The hydraulic conductivity of the duff differed by a factor of 3.8–5.8 between the two forested sites thus influencing the vertical extent of SWR. Indeed, the mineral subsoil of Javea showed wettable or weak hydrophobic conditions probably because leaching of hydrophobic compounds was slowed or prevented at all. Estimations of SWR according to the different indices were in general agreement even if some discrepancies were observed. In particular, at low hydrophobicity levels the SWR indices gathered from the MDI tests were able to signal sub-critical SWR conditions that were not detected by the traditional WDPT index. The WRCT and modified repellency index RIm yielded SWR estimates in reasonable agreement with those obtained with the more cumbersome RI

  7. Field assessment of a novel spatial repellent for malaria control: a feasibility and acceptability study in Mondulkiri, Cambodia.

    Science.gov (United States)

    Liverani, Marco; Charlwood, Jacques Derek; Lawford, Harriet; Yeung, Shunmay

    2017-10-13

    Large-scale use of insecticide-treated nets and indoor residual spraying have contributed to a significant decrease in malaria transmission worldwide. Further reduction and progress towards elimination, however, require complementary control measures which can address the remaining gaps in protection from mosquito bites. Following the development of novel pyrethroids with high knockdown effects on malaria vectors, programmatic use of spatial repellents has been suggested as one potential strategy to fill the gaps. This report explores social and contextual factors that may influence the relevance, uptake and sustainable use of a spatial repellent in two remote villages in Mondulkiri province, Cambodia, with endemic malaria transmission. The repellent consisted of polyethylene emanators, held in an open plastic frame and impregnated with 10% metofluthrin. In a baseline survey, 90.9% of households in Ou Chra (n = 30/33) and 96.6% in Pu Cha (n = 57/59) were interviewed. Behavioural data were collected for all household occupants (n = 448). In both villages, there were times and places in which people remained exposed to mosquito bites. Prior to the installation of the repellent, 50.6 and 59.5% of respondents noted that bites occurred "very often" inside the house and in the outdoor area surrounding the house, respectively. Indoor biting was reported to occur more frequently in the evening, followed by at night, while outdoor biting occurred more frequently in the early morning. In a follow-up survey, spatial repellents were well received in both villages, although 63.2% of respondents would not replace bed nets with repellents. Most participants (96.6%) were willing to use the product again; the mean willingness to pay was US$ 0.3 per unit. A preference for local procurement methods emerged. Widespread use of spatial repellents would not fill all protective gaps, but, if their entomological efficacy can be ascertained, outdoor application has the potential to

  8. The Effects of Feeding Raw Fiber Concentrate on Growth Performance and Blood Metabolites of Suckling Holstein Calves

    OpenAIRE

    Mehdi Dehghan-Banadaky; Fridoon Niazi; Mohsen Ghiasvand

    2012-01-01

    Sixteen female Holstein calves allocated in three treatments including: 1: control, 2: fed raw fiber concentrate (RFC) for 45 days and 3: fed RFC for 90 days. RFC supplement (Vitacel® 200) was added to milk immediately before feeding (10 g/L milk). Withers height and body weights of calves were measured monthly. Individual dry matter intake was recorded daily. Blood samples were taken monthly. The result showed that calves consumed RFC had significantly greater weaning an...

  9. Ionic-Liquid-Infused Nanostructures as Repellent Surfaces.

    Science.gov (United States)

    Galvan, Yaraset; Phillips, Katherine R; Haumann, Marco; Wasserscheid, Peter; Zarraga, Ramon; Vogel, Nicolas

    2018-02-02

    In order to prepare lubricant-infused repellent coatings on silica nanostructures using low vapor pressure ionic liquids as lubricants, we study the wetting behavior of a set of imidazolium-based ionic liquids with different alkyl side chains as a function of the applied surface functionalities. We take advantage of the structural color of inverse opals prepared from a colloidal coassembly technique to study the infiltration of ionic liquids into these nanoporous structures. We find that the more hydrophobic ionic liquids with butyl and hexyl side chains can completely infiltrate inverse opals functionalized with mixed self-assembled monolayers composed of imidazole groups and aliphatic hydrocarbon chains, which we introduce via silane chemistry. These molecular species reflect the chemical nature of the ionic liquid, thereby increasing the affinity between the liquid and solid surface. The mixed surface chemistry provides sufficiently small contact angles with the ionic liquid to infiltrate the nanopores while maximizing the contact angle with water. As a result, the mixed monolayers enable the design of a stable ionic liquid/solid interface that is able to repel water as a test liquid. Our results underline the importance of matching chemical affinities to predict and control the wetting behavior in complex, multiphase systems.

  10. Exponential increase of publications related to soil water repellency

    NARCIS (Netherlands)

    Dekker, L.W.; Oostindie, K.; Ritsema, C.J.

    2005-01-01

    Soil water repellency is much more wide-spread than formerly thought. During the last decades, it has been a topic of study for soil scientists and hydrologists in at least 21 States of the USA, in Canada, Australia, New Zealand, Mexico, Colombia, Chile, Congo, Nepal, India, Hong Kong, Taiwan,

  11. Spatial probability of soil water repellency in an abandoned agricultural field in Lithuania

    Science.gov (United States)

    Pereira, Paulo; Misiūnė, Ieva

    2015-04-01

    Water repellency is a natural soil property with implications on infiltration, erosion and plant growth. It depends on soil texture, type and amount of organic matter, fungi, microorganisms, and vegetation cover (Doerr et al., 2000). Human activities as agriculture can have implications on soil water repellency (SWR) due tillage and addition of organic compounds and fertilizers (Blanco-Canqui and Lal, 2009; Gonzalez-Penaloza et al., 2012). It is also assumed that SWR has a high small-scale variability (Doerr et al., 2000). The aim of this work is to study the spatial probability of SWR in an abandoned field testing several geostatistical methods, Organic Kriging (OK), Simple Kriging (SK), Indicator Kriging (IK), Probability Kriging (PK) and Disjunctive Kriging (DK). The study area it is located near Vilnius urban area at (54 49' N, 25 22', 104 masl) in Lithuania (Pereira and Oliva, 2013). It was designed a experimental plot with 21 m2 (07x03 m). Inside this area it was measured SWR was measured every 50 cm using the water drop penetration time (WDPT) (Wessel, 1998). A total of 105 points were measured. The probability of SWR was classified in 0 (No probability) to 1 (High probability). The methods accuracy was assessed with the cross validation method. The best interpolation method was the one with the lowest Root Mean Square Error (RMSE). The results showed that the most accurate probability method was SK (RMSE=0.436), followed by DK (RMSE=0.437), IK (RMSE=0.448), PK (RMSE=0.452) and OK (RMSE=0.537). Significant differences were identified among probability tests (Kruskal-Wallis test =199.7597 ptested technique. Simple Kriging, DK, IK and PK methods identified the high SWR probabilities in the northeast and central part of the plot, while OK observed mainly in the south-western part of the plot. In conclusion, before predict the spatial probability of SWR it is important to test several methods in order to identify the most accurate. Acknowledgments COST action ES

  12. Effective delivery of a nematode-repellent peptide using a root-cap-specific promoter.

    Science.gov (United States)

    Lilley, Catherine J; Wang, Dong; Atkinson, Howard J; Urwin, Peter E

    2011-02-01

    The potential of the MDK4-20 promoter of Arabidopsis thaliana to direct effective transgenic expression of a secreted nematode-repellent peptide was investigated. Its expression pattern was studied in both transgenic Arabidopsis and Solanum tuberosum (potato) plants. It directed root-specific β-glucuronidase expression in both species that was chiefly localized to cells of the root cap. Use of the fluorescent timer protein dsRED-E5 established that the MDK4-20 promoter remains active for longer than the commonly used constitutive promoter CaMV35S in separated potato root border cells. Transgenic Arabidopsis lines that expressed the nematode-repellent peptide under the control of either AtMDK4-20 or CaMV35S reduced the establishment of the beet cyst nematode Heterodera schachtii. The best line using the AtMDK4-20 promoter displayed a level of resistance >80%, comparable to that of lines using the CaMV35S promoter. In transgenic potato plants, 94.9 ± 0.8% resistance to the potato cyst nematode Globodera pallida was achieved using the AtMDK4-20 promoter, compared with 34.4 ± 8.4% resistance displayed by a line expressing the repellent peptide from the CaMV35S promoter. These results establish the potential of the AtMDK4-20 promoter to limit expression of a repellent peptide whilst maintaining or even improving the efficacy of the cyst-nematode defence. © 2010 The Authors. Plant Biotechnology Journal © 2010 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.

  13. Energetics and sugar-feeding of field-collected anopheline females.

    Science.gov (United States)

    Holliday-Hanson, M L; Yuval, B; Washino, R K

    1997-06-01

    We studied the relationship between nutritional reserves and blood-feeding and sugar-feeding of Anopheles freeborni (Diptera: Culicidae) females in the field. In particular we determined whether (1) females feed on nectar before maturing eggs and initiating host-seeking and (2) the energy reserves of host-seeking females differ from those of non-fed resting females. Twenty-three percent of host-seeking females and 94 percent of gravid females were positive for nectar sugars (containing > 20 micrograms of fructose) versus 55 percent of empty (no blood or eggs) females collected in the morning and 36 percent of empty females collected in the evening. In addition, gravid females contained significantly more calories of nectar than empty, blood-fed, or partially blood-fed females collected in the morning. When the energy reserves of host-seeking and resting females were compared, no differences were found in lipid, trehalose, or glycogen. However, empty females collected in the evening contained more glycogen than empty females collected in the morning. We conclude that gravid females frequently feed on nectar and that fructose is metabolized into glycogen during the day.

  14. Evaluation of four commercial natural products for repellency and toxicity against the lone star tick, Amblyomma americanum (Acari: Ixodidae).

    Science.gov (United States)

    Machtinger, Erika T; Li, Andrew Y

    2017-12-01

    Lone star ticks are aggressive ectoparasites of domestic and wild animals, as well as humans. These ticks can transmit many pathogens that cause disease including Erhlichia and tularemia. Common compounds used for personal protection and area sprays are N-diethyl-3-methyl benzamide (DEET) and permethrin, but public concern over personal and environmental safety require the development of new, safer products. In the current study, four commercially available products (Wondercide, Essentria IC 3 , Vet's Best, and Mosquito Barrier) were tested for both repellent and toxic effects against lone star tick nymphs and adults. Overall, all four products were more effective against nymphs than against adults. Wondercide and Essentria IC 3 were as toxic to nymphs as permethrin at concentrations of 3.13% and higher, and as repellent as DEET at all concentrations. Nymphs were also repelled by Mosquito Barrier and Vet's Best, but these products had about half or less of the repellent effects of Wondercide and Essentria IC 3 at most of the concentrations. Adult ticks were repelled similarly by all products at all tested concentrations, but at lower levels than nymphs. Toxicity of the four tested products on adults was similar at concentrations of 12.5% and below, less than half of what was observed with permethrin with declining effectiveness as concentrations decreased. Overall, these four products may offer a natural way to repel lone star ticks, but further field testing is needed to determine rates of application and residual activity.

  15. Repellency of Dettol, a Commercial Cleaning Product, Against Adult ...

    African Journals Online (AJOL)

    acer

    ABSTRACT: Dettol, a commercial cleaning product was tested for its repellent action against adults of Periplaneta americana (L.). Experimental cage was constructed with pieces of polypropylene plastic material to have a finished form measuring 30×30×60cm. Two cardboard shelters (for each trial) were assembled each ...

  16. 21 CFR 589.2000 - Animal proteins prohibited in ruminant feed.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Animal proteins prohibited in ruminant feed. 589... Animal proteins prohibited in ruminant feed. (a) Definitions—(1) Protein derived from mammalian tissues means any protein-containing portion of mammalian animals, excluding: Blood and blood products; gelatin...

  17. Post-Fire soil water repellency, hydrologic response, and sediment yield compared between grass-converted and chaparral watersheds

    Science.gov (United States)

    Ken R. Hubbert; Pete M. Wohlgemuth; Jan L. Beyers; Marcia G. Narog; Ross Gerrard

    2012-01-01

    In 2002, the Williams Fire burned >90 % of the San Dimas Experimental Forest, providing an opportunity to investigate differences in soil water repellency, peak discharge, and sediment yield between grass-converted and chaparral watersheds. Post-fire water repellency and moisture content were measured in the winter and summer for four years. Peak discharge was...

  18. Resolving the conflict of mating versus blood feeding: exploring role of quick-to-court gene in the mosquito Anopheles culicifacies

    Directory of Open Access Journals (Sweden)

    Tanwee Das De

    2017-10-01

    Full Text Available Mosquitoes are the deadliest animal in the world. Mosquitoes transmit several vector borne disease (VBDs such as malaria, dengue, chikungunya, zika fever, yellow fever and responsible for a loss of millions of lives annually. Though, suppression of mosquito population by means of chemical insecticides plays a crucial role in controlling vector population. However, fast emergence of insecticide resistance limits the efforts and demanding to design alternative molecular tools to fight against these VBDs. One of the potential strategies may include interfering complex feeding and/or mating behavioural properties. Compared to female mosquito male mosquito have an indirect effect in disease transmission and thus least studied. Males induce several post-mating behavioural changes in females, including the induction of host seeking and blood feeding behavior. Although, a successful mating events are guided by non-genetic circadian rhythm, but how genetic factors manages the sequential events of swarm formation, suitable mate finding and aerial coupling remains poorly investigated. While understanding the complex feeding behaviour of adult An. culicifacies female mosquito, we identified and analyzed a unique transcript (383 bp from the olfactory system of the blood-fed mosquito, encoding the ‘quick to court’ (QTC protein. It is a homolog of Drosophila coiled-coil QTC (Q9VMU5 protein and shown to play an important role in driving the male courtship behaviour. A comprehensive in silico analysis predicted a 1536 bp long transcript encoding 511 AA long protein in the mosquito genome. Age dependent and sex specific transcriptional profiling revealed that both male female mosquitoes attain the specific age of adulteration on 5-7 days. Circadian clock dependent Ac-qtc profiling indicated that late evening natural dysregulation of Ac-qtc by unknown mechanism may promote the successful insemination event during active copulation. Together, our findings

  19. Repellent activity of Cnidoscolus phyllacanthus Mart. and Ricinus communis L. extracts against Aedes aegypti L. oviposition behavior

    Directory of Open Access Journals (Sweden)

    Lafayette Pereira Candido

    2015-12-01

    Full Text Available Female Aedes aegypti lay their eggs on nearly any moist substrate. Methods with potential to repel oviposition may reduce infestation, thereby contributing to control of epidemics. We evaluated the influence of Cnidoscolus phyllacanthus and Ricinus communis plant extracts on the oviposition behavior of A. aegypti. Lethal concentrations were first determined in experiments with larvae after 24 h of exposure, after which LC50 and LC90 were used to test oviposition repellency. The experiment consisted of an oviposition preference test based multiple-choice and no-choice assays. The Oviposition Activity Indices (OAIs from the multiple-choice test using both R. communis and C. phyllacanthus were negative, suggesting oviposition repellent and deterrent activity. The LC90 of both plant extracts deterred oviposition by this vector, as demonstrated by an OAI = value of -1. In the choice study, mean oviposition values were significantly different between R. communis and C. phyllacanthus. In the absence of choice, mosquitoes laid eggs independent of the substrate. In conclusion, our OAI values indicate that all substrates used repelled oviposition by A. aegypti.

  20. Molecular Detection of Bartonella Species in Blood-Feeding Bat Flies from Mexico.

    Science.gov (United States)

    Moskaluk, Alexandra E; Stuckey, Matthew J; Jaffe, David A; Kasten, Rickie W; Aguilar-Setién, Alvaro; Olave-Leyva, José Ignacio; Galvez-Romero, Guillermo; Obregón-Morales, Cirani; Salas-Rojas, Mónica; García-Flores, María Martha; Aréchiga-Ceballos, Nidia; García-Baltazar, Anahí; Chomel, Bruno B

    2018-05-01

    Bartonellae are emerging blood-borne bacteria that have been recovered from a wide range of mammalian species and arthropod vectors around the world. Bats are now recognized as a potential wildlife reservoir for a diverse number of Bartonella species, including the zoonotic Candidatus B. mayotimonensis. These bat-borne Bartonella species have also been detected in the obligate ectoparasites of bats, such as blood-feeding flies, which could transmit these bacteria within bat populations. To better understand this potential for transmission, we investigated the relatedness between Bartonella detected or isolated from bat hosts sampled in Mexico and their ectoparasites. Bartonella spp. were identified in bat flies collected on two bat species, with the highest prevalence in Trichobius parasiticus and Strebla wiedemanni collected from common vampire bats (Desmodus rotundus). When comparing Bartonella sequences from a fragment of the citrate synthase gene (gltA), vector-associated strains were diverse and generally close to, but distinct from, those recovered from their bacteremic bat hosts in Mexico. Complete Bartonella sequence concordance was observed in only one bat-vector pair. The diversity of Bartonella strains in bat flies reflects the frequent host switch by bat flies, as they usually do not live permanently on their bat host. It may also suggest a possible endosymbiotic relationship with these vectors for some of the Bartonella species carried by bat flies, whereas others could have a mammalian host.

  1. Persistence of blood changes associated with alteration of the dietary electrolyte balance in commercial pigs after feed withdrawal, transportation, and lairage, and the effects on performance and carcass quality.

    Science.gov (United States)

    Edwards, L N; Engle, T E; Paradis, M A; Correa, J A; Anderson, D B

    2010-12-01

    Increasing dietary electrolyte balance (dEB) has previously been shown to reduce the incidence of nonambulatory and noninjured swine, improve meat quality, and reduce the incidence of gastric ulcers. The objective of this study was to evaluate the effect of dEB under commercial conditions. Due to the variability in feed withdrawal, transport, and lairage conditions in the swine industry, it was necessary to determine first the persistence of blood changes during the marketing process after alteration of dEB. Sixteen pens of 8 crossbred barrows were assigned to a low (121 mEq/kg) or high (375 mEq/kg) dEB diet, calculated as Na(+) + K(+) - Cl(-), to determine the persistence of blood changes associated with the alteration of dEB. Diets were formulated to meet or exceed NRC (1998) requirements for energy, protein, vitamins, and minerals. Dietary treatments were provided for ad libitum intake for 3 d before slaughter. Before transport, animals were fasted in the barn for approximately 10 h. After fasting, animals were shipped to the packing plant, rested for 8 h, and subsequently slaughtered. Initial and final BW of the animals were obtained. Blood was sampled at baseline (2 d before administration of diets), before feed withdrawal (0 h), after feed withdrawal (10 h), and at exsanguination (20 h). Consumption of the high dEB diet for 3 d resulted in an increase in blood TCO(2) (P = 0.001), HCO(3)(-) (P = 0.001), and base excess (P = 0.0003) and a decrease in Cl(-) (P = 0.0002) and anion gap (P = 0.01). These differences, however, were not maintained for any of the blood components after the 10-h feed withdrawal (P > 0.22). Increasing dEB had no adverse effects (P > 0.18) on growth performance, meat quality, or carcass yield and did not decrease pars esophageal ulcer scores. This study demonstrated that the effect of dEB on blood components was not maintained after a 10-h feed withdrawal. Therefore, it is likely that the ability of the animal to withstand any increased

  2. DEET, Active Substance Of Repellent That Effective And Safe For Travelers

    Directory of Open Access Journals (Sweden)

    Made Ika Lestari

    2013-10-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE Increased flow of tourism to the tropics and the changing patterns of vector-borne diseases require increased protection against insects. To prevent transmission of the disease is done several ways that increase self-protection by using mosquito repellent can protect travelers while outdoor activities. One option is active formula mosquito repellent DEET. The purpose of this paper is to determine the best dosage forms for travelers DEET., To determine the effectiveness and safety of DEET and to know the workings of the active ingredient DEET. The method of writing is the literature search through medical journals and articles. From the search was obtained, the most appropriate anti-mosquito travelers to use while on the move outdoors in the dosage form is DEET lotion applied to the skin as the most secure and durable because it does not easily evaporate. Mosquito repellent containing DEET has been proven effective and safe for use in adults, children, and pregnant women, but should still follow the instructions. The workings of the mosquito repellent DEET mosquito dispel is manipulating 1-Octen-3-ol used by mosquitoes to detect human presence. So ORN (olfactory receptor neurons in the mosquitoes can not respond anymore to the maximum, so that people avoid the bites nyamuk. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New

  3. Determination of the efficacy of two water repellents applied to granite

    Directory of Open Access Journals (Sweden)

    Rivas, T.

    1998-03-01

    Full Text Available We evaluated the efficacy of two water-repellents applied to three types of granitic rock widely used in building construction and restoration in Galicia (NW Spain. The depth of penetration of the water-repellents was determined by measuring capillary absorption by the treated rock. The efficacies of the water-repellent were evaluated in terms of two parameters characteristic of surface wet: water-rock contact angle and the time taken for absorption of microgroplets. The effects of the treatments on the rocks' surface color and permeability to water vapor were also determined. The results indicate that neither water-repellent effectively penetrates the rock surface, and both induce undesirably high reductions in vapor permeability. Notwithstanding, both agents effectively improved the rocks' resistance to surface wetting, without altering its surface color. Overall, determination of water-rock contact angle and the time taken for absorption of microdroplets, together with colorimetric characterization of the treated rock, constitutes an useful approach to evaluation of the effects of water-repellents on granitic rocks. Nonetheless, it should be borne in mind that the marked heterogeneity of this type of rock, and the associated mineralogy and dominant type of fissuration are sources of considerable variation in the measurement parameters.

    Se presentan los resultados de la aplicación de dos tratamientos hidrofugantes a tres rocas graníticas ampliamente utilizadas en la construcción y restauración en Galicia. Se ha determinado la profundidad de penetración de los hidrofugantes a través de la absorción capilar, la eficacia de los tratamientos comparando dos parámetros relacionados con el mojado superficial (ángulo de contacto roca-agua y tiempo de absorción de microgotas, y las variaciones en el color y en la permeabilidad al vapor. Se comprueba que si bien ambos tratamientos penetran deforma muy escasa en las rocas graníticas y

  4. Culex quinquefasciatus (Diptera: Culicidae) as a potential West Nile virus vector in Tucson, Arizona: Blood meal analysis indicates feeding on both humans and birds

    OpenAIRE

    Zinser, Margaret; Ramberg, Frank; Willott, Elizabeth

    2004-01-01

    Most reports from the United States suggest Culex quinquefasciatus mosquitoes feed minimally on humans. Given the abundance of C. quinquefasciatus in residential Tucson and parts of metropolitan Phoenix, and the arrival of West Nile virus to this area, discovering the blood meal hosts of the local population is important. Using a sandwich ELISA technique, the local C. quinquefasciatus were found to feed on both humans and birds. This suggests they should be considered potential West Nile viru...

  5. Field evaluation of the efficacy of proprietary repellent formulations with IR3535 and picaridin against Aedes aegypti.

    Science.gov (United States)

    Naucke, T J; Kröpke, R; Benner, G; Schulz, J; Wittern, K P; Rose, A; Kröckel, U; Grünewald, H W

    2007-06-01

    Seven proprietary repellent formulations (3 hydro-alcoholic spray solutions and 4 skin lotions) with active ingredient IR3,535 (ethyl butylacetylaminopropionate, EBAAP) or Picaridin (hydroxyethyl isobutyl piperidine carboxylate, KBR 3,023, Bayrepel) were tested in a field study on 10 test persons over a period of 10 h for their efficacy at preventing bites. The tests were conducted in Belo Horizonte, Brazil on field populations of the yellow fever mosquito Aedes aegypti. The concentration of the active substances ranged from 10% to 20%. All the tested samples provided lasting protection (time to first bite) over several hours: ranging from 5 h 20 min to 6 h 50 min with a mean of approximately 6 h. The longest protection until the second bite (=first confirmation bite) was approximately 7 h 40 min, whereas the shortest protection was 6 h 50 min. The longest protection until the third bite (=second confirmation bite) was 8 h 35 min, whereas the shortest protection was 7 h 40 min. In the control tests in which none of the samples were applied, the mean times until the first, second and third bites were 26, 46 and 59 min, respectively. The basis for this field study was provided by two American guidelines, which have the greatest international acceptance. The first is a draft guideline from the Environmental Protection Agency (EPA (United States Environmental Protection Agency), Product performance test guidelines. OPPTS 810.3700. Insect repellents for human skin and outdoor premises. Public Draft, 1999) and the second is a standard from the American Society for Testing and Materials (ASTM (American Society for Testing and Materials International), E 939-94 (reapproved 2,000): standard test method of field testing topical applications of compounds as repellents for medically important and pest arthropods (including insects, ticks, and mites): I. Mosquitoes, 2,000). Both guidelines recommend measuring the duration of protection until the first and second bites and also

  6. Insect Repellents: Modulators of Mosquito Odorant Receptor Activity

    Science.gov (United States)

    2010-08-01

    Laboratory, Henry A. Wallace Beltsville Agricultural Research Center, Plant Sciences Institute, Agricultural Research Service, United States Department...origin. 2-U is a naturally occurring compound produced by the glandular trichomes of wild tomato plants as part of a plant defense mechanism against...antennal OSNs responding to carboxylic acids and monoterpenes [23]. In our study, we investigate the action of 4 insect repellents on the activities of

  7. Facing the rain after the phase out: Performance evaluation of alternative fluorinated and non-fluorinated durable water repellents for outdoor fabrics.

    Science.gov (United States)

    Schellenberger, S; Gillgard, P; Stare, A; Hanning, A; Levenstam, O; Roos, S; Cousins, I T

    2018-02-01

    Fluorinated durable water repellent (DWR) agents are used to obtain water and stain repellent textiles. Due to the on-going phase-out of DWRs based on side-chain fluorinated polymers (SFP) with "long" perfluoroalkyl chains, the textile industry lacks suitable alternatives with comparable material characteristics. The constant development and optimization of SFPs for textile applications initiated more than half a century ago has resulted in a robust and very efficient DWR-technology and textiles with exceptional hydro- and oleo-phobic properties. The industry is now in the predicament that the long-chain SFPs with the best technical performance have undesirable toxicological and environmental behaviour. This study provides a comprehensive overview of the technical performance of presently available fluorinated and non-fluorinated DWRs as part of a chemical alternatives assessment (CAA). The results are based on a study with synthetic outdoor fabrics treated with alternative DWRs and tested for repellency using industrial standard and complementary methods. Using this approach, the complex structure-property relationships of DWR-polymers could be explained on a molecular level. Both short-chain SFPs and non-fluorinated DWRs showed excellent water repellency and durability in some cases while short-chain SFPs were the more robust of the alternatives to long-chain SFPs. A strong decline in oil repellency and durability with perfluoroalkyl chain length was shown for SFP DWRs. Non-fluorinated alternatives were unable to repel oil, which might limit their potential for substitution in textile application that require repellency towards non-polar liquids. Copyright © 2017. Published by Elsevier Ltd.

  8. Intensive liquid feeding of dairy calves with a medium crude protein milk replacer: Effects on performance, rumen, and blood parameters.

    Science.gov (United States)

    de Paula, M R; Oltramari, C E; Silva, J T; Gallo, M P C; Mourão, G B; Bittar, C M M

    2017-06-01

    The objective of this study was to evaluate the effects of different liquid-feeding systems using a medium crude protein milk replacer on performance, rumen, and blood parameters. Thirty newborn Holstein calves were blocked according to birth weight and date of birth, and randomly distributed to different liquid-feeding systems: conventional (4 L/d), intensive (8 L/d), or step-up/step-down (wk 1, 4 L/d; wk 2 to 6, 8 L/d; wk 7 and 8, 4 L/d). The commercial milk replacer (12.5% solids, 20.2% crude protein, 15.6% fat) was fed twice daily (0700 and 1700 h) until calves were weaned, at 8 wk of age. Calves were individually housed in wood hutches, with free access to water and starter concentrate, and to hay only after weaning. They were followed through 10 wk of age. Milk replacer and starter intake were inversely affected by feeding system. After weaning, starter intake and hay intake were similar among feeding systems. Total dry matter intake was higher during the liquid-feeding period for calves on the intensive system compared to calves on the conventional system, but conventional feeding resulted in the highest dry matter intake after weaning. Feed efficiency was similar among feeding systems before and after weaning. Average body weight and daily gain were not affected by feeding system before or after weaning. During liquid feeding, diarrhea occurrence was lower for calves on the conventional system; however, when calves on the step-up/step-down system were fed lower volumes of liquid feed, diarrhea occurrence was similar to that of calves on the conventional system. Plasma concentrations of β-hydroxybutyrate were higher for calves on the conventional system, reflecting starter intake. Rumen pH, short-chain fatty acids, and N-NH 3 were not affected by feeding system. Feeding higher volumes of milk replacer with a medium crude protein content had no beneficial effect on the performance of calves up to 10 wk of age. Copyright © 2017 American Dairy Science

  9. Essential oils of aromatic Egyptian plants repel nymphs of the tick Ixodes ricinus (Acari: Ixodidae).

    Science.gov (United States)

    El-Seedi, Hesham R; Azeem, Muhammad; Khalil, Nasr S; Sakr, Hanem H; Khalifa, Shaden A M; Awang, Khalijah; Saeed, Aamer; Farag, Mohamed A; AlAjmi, Mohamed F; Pålsson, Katinka; Borg-Karlson, Anna-Karin

    2017-09-01

    Due to the role of Ixodes ricinus (L.) (Acari: Ixodidae) in the transmission of many serious pathogens, personal protection against bites of this tick is essential. In the present study the essential oils from 11 aromatic Egyptian plants were isolated and their repellent activity against I. ricinus nymphs was evaluated Three oils (i.e. Conyza dioscoridis L., Artemisia herba-alba Asso and Calendula officinalis L.) elicited high repellent activity in vitro of 94, 84.2 and 82%, respectively. The most active essential oil (C. dioscoridis) was applied in the field at a concentration of 6.5 µg/cm 2 and elicited a significant repellent activity against I. ricinus nymphs by 61.1%. The most repellent plants C. dioscoridis, C. officinalis and A. herba-alba yielded essential oils by 0.17, 0.11 and 0.14%, respectively. These oils were further investigated using gas chromatography-mass spectrometry analysis. α-Cadinol (10.7%) and hexadecanoic acid (10.5%) were the major components of C. dioscoridis whereas in C. officinalis, α-cadinol (21.2%) and carvone (18.2%) were major components. Artemisia herba-alba contained piperitone (26.5%), ethyl cinnamate (9.5%), camphor (7.7%) and hexadecanoic acid (6.9%). Essential oils of these three plants have a potential to be used for personal protection against tick bites.

  10. Influence of water-repellent treatment on the properties lime and lime pozzolan mortars

    Directory of Open Access Journals (Sweden)

    Fortes Revilla, C.

    2001-06-01

    Full Text Available The influence that water-repellent products can have on physical and micro-structural properties of lime mortars, and lime plus pozzolan mortars has been studied. Three water repellent products have been used. Mixes of the previously mentioned three water repellents plus a biocide product were also applied. Treatments make the total porosity and saturation coefficient of both mortars to decrease, while colorimetric coordinates bear little alteration. All treatments with water repellent products provided mortars with a hydrophobic property index close to 100%. Durability of such mortars has been also studied: salt crystallization test, frost-thaw and dry-wet cycles, as well as ultraviolet radiation test were carried out. Relationship between mortars behavior and their porosity and saturation coefficient were found.

    En el presente trabajo se ha estudiado la influencia de la aplicación de productos hidrofugantes a morteros de cal y morteros de cal y puzolana sobre sus propiedades físicas y microestructurales. Se han estudiado tres productos hidrofugantes. También han sido estudiados dichos productos junto con un biocida. La porosidad total y el coeficiente de saturación de ambos tipos de morteros se ve reducido por el efecto de los tratamientos mientras que las coordenadas colorimétricas se ven poco alteradas. Todos los tratamientos confieren un índice de hidrofobicidad a los morteros próximo al 100%. Asimismo, también se ha estudiado la durabilidad de dichos morteros frente a la cristalización de sales, hielo-deshielo, los ciclos de humedad-sequedad y radiaciones ultravioleta. Se relaciona el comportamiento de los morteros con su porosidad y el coeficiente de saturación.

  11. Evaluation of DEET and eight essential oils for repellency against nymphs of the lone star tick, Amblyomma americanum (Acari: Ixodidae)

    Science.gov (United States)

    Eight commercially available essential oils (oregano, clove, thyme, vetiver, sandalwood, cinnamon, cedarwood, and peppermint) were evaluated for repellency against host-seeking nymphs of the lone star tick, Amblyomma americanum. Concentration- repellency response was established using the vertical ...

  12. Cosmicflows-3: Cold Spot Repeller?

    Energy Technology Data Exchange (ETDEWEB)

    Courtois, Hélène M.; Graziani, Romain; Dupuy, Alexandra [University of Lyon, UCB Lyon 1, CNRS/IN2P3, IPN, Lyon (France); Tully, R. Brent [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Hoffman, Yehuda [Racah Institute of Physics, Hebrew University, Jerusalem, 91904 (Israel); Pomarède, Daniel [Institut de Recherche sur les Lois Fondamentales de l’Univers, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette (France)

    2017-09-20

    The three-dimensional gravitational velocity field within z ∼ 0.1 has been modeled with the Wiener filter methodology applied to the Cosmicflows-3 compilation of galaxy distances. The dominant features are a basin of attraction and two basins of repulsion. The major basin of attraction is an extension of the Shapley concentration of galaxies. One basin of repulsion, the Dipole Repeller, is located near the anti-apex of the cosmic microwave background dipole. The other basin of repulsion is in the proximate direction toward the “Cold Spot” irregularity in the cosmic microwave background. It has been speculated that a vast void might contribute to the amplitude of the Cold Spot from the integrated Sachs–Wolfe effect.

  13. Domestic animal hosts strongly influence human-feeding rates of the Chagas disease vector Triatoma infestans in Argentina.

    Directory of Open Access Journals (Sweden)

    Ricardo E Gürtler

    Full Text Available The host species composition in a household and their relative availability affect the host-feeding choices of blood-sucking insects and parasite transmission risks. We investigated four hypotheses regarding factors that affect blood-feeding rates, proportion of human-fed bugs (human blood index, and daily human-feeding rates of Triatoma infestans, the main vector of Chagas disease.A cross-sectional survey collected triatomines in human sleeping quarters (domiciles of 49 of 270 rural houses in northwestern Argentina. We developed an improved way of estimating the human-feeding rate of domestic T. infestans populations. We fitted generalized linear mixed-effects models to a global model with six explanatory variables (chicken blood index, dog blood index, bug stage, numbers of human residents, bug abundance, and maximum temperature during the night preceding bug catch and three response variables (daily blood-feeding rate, human blood index, and daily human-feeding rate. Coefficients were estimated via multimodel inference with model averaging.Median blood-feeding intervals per late-stage bug were 4.1 days, with large variations among households. The main bloodmeal sources were humans (68%, chickens (22%, and dogs (9%. Blood-feeding rates decreased with increases in the chicken blood index. Both the human blood index and daily human-feeding rate decreased substantially with increasing proportions of chicken- or dog-fed bugs, or the presence of chickens indoors. Improved calculations estimated the mean daily human-feeding rate per late-stage bug at 0.231 (95% confidence interval, 0.157-0.305.Based on the changing availability of chickens in domiciles during spring-summer and the much larger infectivity of dogs compared with humans, we infer that the net effects of chickens in the presence of transmission-competent hosts may be more adequately described by zoopotentiation than by zooprophylaxis. Domestic animals in domiciles profoundly affect the

  14. Blood Feeding Status, Gonotrophic Cycle and Survivorship of Aedes (Stegomyia) aegypti (L.) (Diptera: Culicidae) Caught in Churches from Merida, Yucatan, Mexico.

    Science.gov (United States)

    Baak-Baak, C M; Ulloa-Garcia, A; Cigarroa-Toledo, N; Tzuc Dzul, J C; Machain-Williams, C; Torres-Chable, O M; Navarro, J C; Garcia-Rejon, J E

    2017-12-01

    Blood-feeding status, gonotrophic cycle, and survival rates of Aedes (Stegmyia) aegypti (L.) was investigated in catholic churches from Merida, Yucatan. Female Ae. aegypti were caught using backpack aspirator during 25 consecutive days in rainy (2015) and dry season (2016). Blood-feeding status was determined by external examination of the abdomen and classified as unfed, fed, and gravid. Daily changes in the parous-nulliparous ratio were recorded, and the gonotrophic cycle length was estimated by a time series analysis. Also, was observed the vitellogenesis to monitoring egg maturity. In total, 408 females Ae. aegypti were caught, and there was a significant difference in the number of females collected per season (Z = -6.729, P ≤ 0.05). A great number was caught in the rainy season (n = 329). In the dry season, 79 females were caught, which the fed females were twice greatest than the unfed. The length of gonotrophic cycle was estimated on the base of a high correlation coefficient value appearing every 4 days in rainy at 26.7 ± 1.22°C, and 3 days in dry season at 29.8 ± 1.47°C. The daily survival rate of the Ae. aegypti population was higher in both seasons, 0.94 and 0.93 for the rainy and dry season, respectively. The minimum time estimated for developing mature eggs after blood feeding was similar in both seasons (3.5 days in rainy versus 3.25 days in dry). The measurement of the vectorial capacity of Ae. aegypti in catholic churches could help to understand the dynamics of transmission of arboviruses in sites with high human aggregation.

  15. Insecticidal and repellant activities of plants oil against stored grain pest, Tribolium castaneum (Herbst (Coleoptera:Tenebrionidae

    Directory of Open Access Journals (Sweden)

    S.R.Pugazhvendan

    2012-05-01

    Full Text Available Objective: The present investigation was aimed to assess the impact of five plants oil for their insecticidal and repellent activity against Tribolium castaneum (Herbst, a stored grain pest and they were tested in the laboratory. Method: Five plants oil Citrus autantium, Cinnamomum zeylanicum, Gaultheria fragrantissima, Lavandula officinalis, and Ocimum sanctum were evaluated for their insecticidal and repellent activities against T. castaneum by adapting the standard protocol in vitro. Results: In Tulsi oil showed powerful repellent against T. castaneum beetles at both the concentration and this property can be clearly seen from the values at 5毺 1 (-0.60 and -0.73 in 1h and 6hr respectively and 10毺 1 (-0.56 and -0.81 in 1h and 6h respectively. Tulsi oil had more repelling property than other oil tested here against T. castaneum. Maximum percentage of mortality (76 and 92% at 48h and 72 hours after treatment respectively in Tulsi oil. Wintergreen oil showed 86% mortality at 72 hours after treatment. Conclusions: The present work for botanical products to control the insect pest of stored grain T. castaneum .These results suggest the presence of actives principles in the plant oils. Further exploration of active principles and their structural elucidations are underway.

  16. Variation in the repellency effects of the leaves of Mentha piperita ...

    African Journals Online (AJOL)

    Administrator

    2011-09-21

    Sep 21, 2011 ... The repellency effects of Mentha piperita leaves, collected from two different locations in ... of trace metals were reported from the soil and plant collected from Malelane (p < 0.05). ... an increased concentration of chromium.

  17. Effects of a neem extract on blood feeding, oviposition and oocyte ultrastructure in Anopheles stephensi Liston (Diptera: Culicidae).

    Science.gov (United States)

    Lucantoni, L; Giusti, F; Cristofaro, M; Pasqualini, L; Esposito, F; Lupetti, P; Habluetzel, A

    2006-12-01

    Secondary metabolites of the neem tree (Azadirachta indica A. Juss., Meliaceae) exhibit a wide range of biological activities in insects. However, few studies have addressed the effects of neem extracts or compounds in arthropods of medical importance. In this study, a laboratory strain of Anopheles stephensi was used to assess the effects of a commercial formulation (Neem Azal) (NA)), containing azadirachtin A at 34%, on blood feeding, oviposition and oocyte ultrastructure. Oral administration of Neem Azal) to A. stephensi females through artificial blood meals did impair blood intake and oviposition in a concentration dependent manner. Similar results were obtained on females, which had consumed Neem Azal) in sucrose solution before taking a blood meal of plain blood. Neem treated females displayed a delay in oocyte development in both the phase of vitellogenesis and the phase of choriogenesis. The ultrastructural studies on ovaries from Neem Azal) treated females revealed distinct structural modifications indicative of: (i) a complete block of oogenesis, (ii) impairment of vitellogenesis and vitelline envelope formation, (iii) a severe degeneration of follicle cells. In agreement with results obtained in other insects, this study indicates that Neem Azal) impairs hormone control of oogenesis and exerts a cytotoxic effect on both follicular cells and oocytes of the Asian malaria vector A. stephensi.

  18. Manufacturing and characterisation of water repellent surfaces

    DEFF Research Database (Denmark)

    De Grave, Arnaud; Botija, Pablo; Hansen, Hans Nørgaard

    2006-01-01

    design criteria for such surfaces. The problem of adapting this behaviour to artificially roughened surfaces is addressed by providing design criteria for superhydrophobic, water-repellent and self-cleaning surfaces according to the concrete performance desired for them. Different kind of manufacturing...... techniques are investigated and the production of patterned micro structured surfaces following two different manufacturing techniques is reported. The first is a combination of laser manufacturing and hot embossing on polystyrene. To compare geometry and functionality a non-silicon based lithography...

  19. Culex quinquefasciatus (Diptera: Culicidae as a potential West Nile virus vector in Tucson, Arizona: Blood meal analysis indicates feeding on both humans and birds

    Directory of Open Access Journals (Sweden)

    Margaret Zinser

    2004-06-01

    Full Text Available Most reports from the United States suggest Culex quinquefasciatus mosquitoes feed minimally on humans. Given the abundance of C. quinquefasciatus in residential Tucson and parts of metropolitan Phoenix, and the arrival of West Nile virus to this area, discovering the blood meal hosts of the local population is important. Using a sandwich ELISA technique, the local C. quinquefasciatus were found to feed on both humans and birds. This suggests they should be considered potential West Nile virus vectors.

  20. Chemical Composition and Repellent Activity of Achillea vermiculata and Satureja hortensis against Anopheles stephensi

    Directory of Open Access Journals (Sweden)

    Masoumeh Pirmohammadi

    2016-01-01

    Full Text Available Background: One of the best ways to control the malaria disease and to be protected human against Anopheles mos­quito biting is the use of repellents. Throughout repellents, herbal ones may be an appropriate and safe source for protection.Methods: Chemical constituents of Achillea vermiculata and Satoreja hortensis were determined by using gas chromatography-mass spectrometry. Efficacy and the protection time of these plants were assessed on Anopheles stephensi under the laboratory condition.Results: The mean assessed protection time and efficacy for A. vermiculata was 2.16 and 3.16 hours respectively and the obtained ED50 and ED90 for this plant was 5.67 and 63 µl/cm2 respectively. The figured for S. hortensis was 4.16 and 5 hours respectively.  ED50 and ED90 for this plant were 5.63 and 45.75µl/cm2 respectively.Conclusion: Results of investigation showed that S. hortensis plant has an acceptable protection time, therefore, this plant could be considered as a good herbal repellent against anopheles mosquitoes.

  1. Use of chemosensory cues as repellents for sea lamprey: Potential directions for population management

    Science.gov (United States)

    Imre, I.; Brown, G.E.; Bergstedt, R.A.; McDonald, R.

    2010-01-01

    Sea lamprey invaded the Great Lakes in the early 20th century and caused an abrupt decline in the population densities of several native fish species. The integrated management of this invasive species is composed of chemical (lampricide) applications, low-head barrier dams, adult trapping and sterile male release. Recently, there has been an increased emphasis on the development of control methods alternative to lampricide applications. We propose as an alternative-control method the use of chemosensory cues as repellents for sea lamprey population management. Based on the available evidence at this time, we suggest that injury-released chemical alarm cues show promise as repellents for sea lamprey and further research should be directed at determining whether sea lamprey show an avoidance response to these types of chemosensory cues. From a management perspective, these chemosensory cues could be used to restrict sea lamprey access to spawning grounds. Repellents could also be used together with attractants like sex pheromones to manipulate sea lamprey behavior, similar to the "push-pull" strategies utilized with insect pests. ?? 2010 Elsevier B.V.

  2. Relative Performance of Indoor Vector Control Interventions in the Ifakara and the West African Experimental Huts.

    OpenAIRE

    Oumbouke, Welbeck A; Fongnikin, Augustin; Soukou, Koffi B; Moore, Sarah J; N'Guessan, Raphael

    2017-01-01

    Background West African and Ifakara experimental huts are used to evaluate indoor mosquito control interventions, including spatial repellents and insecticides. The two hut types differ in size and design, so a side-by-side comparison was performed to investigate the performance of indoor interventions in the two hut designs using standard entomological outcomes: relative indoor mosquito density (deterrence), exophily (induced exit), blood-feeding and mortality of mosquitoes. Methods Metoflut...

  3. Water repellency of two forest soils after biochar addition

    Science.gov (United States)

    D. S. Page-Dumroese; P. R. Robichaud; R. E. Brown; J. M. Tirocke

    2015-01-01

    Practical application of black carbon (biochar) to improve forest soil may be limited because biochar is hydrophobic. In a laboratory, we tested the water repellency of biochar application (mixed or surface applied) to two forest soils of varying texture (a granitic coarse-textured Inceptisol and an ash cap fine-textured Andisol) at four different application rates (0...

  4. Insecticidal and insect-repellent activities of essential oils from Verbenaceae and Anacardiaceae against Rhizopertha dominica.

    Science.gov (United States)

    Benzi, Verónica S; Murrayb, Ana P; Ferrero, Adriana A

    2009-09-01

    Essential oils extracted from leaves of Aloysia polystachya and A. citriodora (Verbenaceae) and from leaves and fruits of Schinus molle var. areira (Anacardiaceae) were tested for their repellent and toxic activities against adults of Rhizopertha dominica (Coleoptera: Bostrichidae). Topical application and filter paper assays were employed for contact toxicity studies; filter paper impregnation was also used for fumigant and repellent assays. In topical tests A. polystachya was as effective as S. molle leaves. In the case of repellent assays, A. citriodora was the most effective oil based on the class scale. A. polystachya was the most toxic plant on contact toxicity by filter paper assay (LC50 26.6 mg/cm2). Fumigant toxicity was only evaluated with fruits and leaves of S. molle, and no significant differences were found between them. Published data are included to compare the fumigant toxicity of S. molle with that of A. citridora and A. polystachya.

  5. Pest repellent properties of ant pheromones

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    2012-01-01

    of ant pheromones may be sufficient to repel pest insects from ant territories. The study of ant semiochemicals is in its infancy, yet, evidence for their potential use in pest management is starting to build up. Pheromones from four of five tested ant species have been shown to deter herbivorous insect...... prey and competing ant species are also deterred by ant deposits, whereas ant symbionts may be attracted to them. Based on these promising initial findings, it seems advisable to further elucidate the signaling properties of ant pheromones and to test and develop their use in future pest management....

  6. Feed-derived volatile basic nitrogen increases reactive oxygen species production of blood leukocytes in lactating dairy cows.

    Science.gov (United States)

    Tsunoda, Ei; Gross, Josef J; Kawashima, Chiho; Bruckmaier, Rupert M; Kida, Katsuya; Miyamoto, Akio

    2017-01-01

    The present study investigated over 9 months the changes of fermentative quality of total mixed rations (TMR) containing grass silage (GS) as a major component, associated with changes in the volatile basic nitrogen (VBN) levels in an experimental dairy farm. Effects of VBN levels in TMR on metabolic parameters, reactive oxygen species (ROS) production by blood polymorphonuclear leukocytes (PMNs) and conception rates for dairy cows were analyzed. According to VBN levels in TMR during survey periods, three distinct phases were identified; phase A with low VBN; phase B with high VBN; and phase C with mid-VBN. Metabolic parameters in blood were all within normal range. However, during phases B and C, nitrogen metabolic indices such as blood urea nitrogen and milk urea nitrogen showed higher levels compared to those in phase A, and a simultaneous increase in ROS production by blood PMNs and the load on hepatic function in metabolic parameters was observed in the cows with a lower conception rate. This suggests that feeding TMR with elevated VBN levels due to poor fermented GS results in stimulation of ROS production by PMNs by ammonia, and negatively affects metabolism and reproductive performance in lactating dairy cow. © 2016 Japanese Society of Animal Science.

  7. Effect of concentrate level on feeding behavior and rumen and blood parameters in dairy goats: relationships between behavioral and physiological parameters and effect of between-animal variability.

    Science.gov (United States)

    Giger-Reverdin, S; Rigalma, K; Desnoyers, M; Sauvant, D; Duvaux-Ponter, C

    2014-07-01

    This work aimed first to compare 2 diets differing in their percentage of concentrate [low (LO): 30% concentrate vs. High (HI): 60% concentrate] by measuring simultaneously feeding behavior, rumen parameters, blood and plasma parameters, and milk yield and composition in 8 mid-lactation goats. The second aim was to study the interrelationships between these variables and to analyze the between-animal variability to better understand the between-animal differences in acidosis susceptibility. All of the animals received the 2 diets ad libitum as total mixed ration according to a crossover design of two 4-wk periods. Mean daily DMI was similar between the 2 diets but the variability was higher for the HI than for the LO diet. Goats produced more milk when fed the HI diet compared with the LO diet but with a lower fat:protein ratio (0.81 vs. 0.99). They ate more rapidly the HI than the LO diet but stopped eating sooner after the afternoon feed allowance, and spent less time chewing. The increase in concentrate percentage modified rumen parameters: the pH and acetate:propionate ratio decreased and total VFA, ammonia, and soluble carbohydrate concentrations increased. Hematocrit, plasma NEFA, and blood K and Ca concentrations decreased but glycemia and uremia increased. Other parameters were not modified: milk fat content, blood pH, and bicarbonate and Na concentrations. A large between-animal variability was detected for all the measured parameters, especially for feeding behavior, with important consequences on rumen and blood parameters. This work confirmed the effects of a high percentage of concentrate on feeding behavior, rumen and blood parameters, and milk production, and some known relationships such as the positive link between rumen pH and chewing index. It also pointed out other relationships between parameters seldom measured at the same time, such as rumen redox potential or blood pH and chewing index, or the negative link between blood and rumen pH. When

  8. Field trial of the spatial repellency of metofluthrin-impregnated plastic strip against mosquitoes in shelters without walls (Beruga) in Lombok, Indonesia.

    OpenAIRE

    Kawada, Hitoshi; Maekawa, Yoshihide; Takagi, Masahiro

    2005-01-01

    Field trials on the spatial repellency of metofluthrin-impregnated plastic strips for mosquitoes present in shelters without walls (beruga) were carried out in Lombok, Indonesia. A major reduction in the incidence of human biting by Culex quinquefasciatus was achieved, and the use of two strips per beruga repelled >60% of the mosquitoes for at least 11 wk while four strips repelled >60% of the mosquitoes for more than 15 weeks. The technique was found to be a practical long-term solution for ...

  9. Effects of a layer of vegetative ash layer on wettable and water repellent soil hydrology

    Science.gov (United States)

    Bodí, Merche B.; Doerr, Stefan H.; Cerdà, Artemi; Mataix-Solera, Jorge

    2010-05-01

    Following a wildfire, a layer of vegetative ash often covers the ground until it is dissolved or redistributed by wind and water erosion. Much of the existing literature suggests that the ash layer temporally reduces infiltration by clogging soil pores or by forming a surface crust (Mallik et al., 1984; Onda et al., 2008). However, an increasing number of field-based studies have found that, at least in the short term, ash increases infiltration by storing rainfall and protecting the underlying soil from sealing (Cerdà and Doerr, 2008; Woods and Balfour, 2008). On the other hand, after a fire the soil may have produced, enhanced or reduced its water repellency (Doerr et al., 2000). Very few studies have been taken into account the interaction of the ash and the repellent soil. The layer of ash may have similar role as a litter layer in delaying runoff and reducing erosion by storing water. In order to examine this interaction, it was been made a series of experiments using a laboratory rainfall simulation. It has been assessed the effects of an ash layer i) on a wettable and water repellent soil (WDPT > 7200s), ii) with different ash thicknesses (bare soil and 5 mm, 15 mm and 30 mm of ash), iii) preceding and following the first rain after a fire when the ground is still wetted and after being partially dried. Three replicates were done, being a total of 40 simulations. The ash used was collected from a Wildfire in Teruel (Spain) during summer of 2009. The simulations were conducted in metal boxes of 30x30 cm and filled with 3 cm of soil. The slope of the box was set at 10° (17%) and the intensity applied was 78-84 mm h-1during 40 minutes. The splash detachment was determined also using four splash cups. Overland flow and subsurface drainage was collected at 1-minute intervals and the former stored every 5 min to allow determination of sediment concentrations, yield and erosion rates. Each sample was examined at the end in terms of water repellency, infiltration

  10. Deltamethrin-resistant German Cockroaches Are Less Sensitive to the Insect Repellents DEET and IR3535 than Non-resistant Individuals.

    Science.gov (United States)

    Mengoni, Sofía L; Alzogaray, Raúl A

    2018-04-02

    The German cockroach, Blattella germanica (L.) (Blattodea: Blattellidae), is a serious worldwide pest with a considerable economical and sanitary impact. It is mainly controlled by the application of synthetic insecticides, but repeated use of these substances has promoted the appearance of resistance in cockroach populations throughout the world. The aim of this study was to compare the behavior of deltamethrin-susceptible (CIPEIN colony) and deltamethrin-resistant (JUBA and VGBA colonies) first instar nymphs exposed to the repellents N,N-diethyl-3-methylbenzamide (DEET) and ethyl 3-[acetyl(butyl)amino]propanoate (IR3535). Firstly, the behavior of the nymphs was assessed in an experimental arena in the absence of repellents. The parameters Distance Traveled, Velocity, Mobility Time, and Time Spent (in each half of the arena) were quantified using an image analyser, and showed that the behavior elicited by the three colonies was similar. After this, the behavior of the nymphs was quantified in an arena, half of which had been treated with repellent. The repellency of DEET increased as a linear function of log concentration for the three colonies. DEET elicited repellency as from a concentration of 97.49 µg/cm2 for the CIPEIN and JUBA colonies and 194.98 µg/cm2 for the VGBA colony. The repellency of IR3535 was weaker and started at a concentration of 389.96 µg/cm2 for the CIPEIN colony, 779.92 μg/cm2 for JUBA, and 1559.84 μg/cm2 for VGBA . Finally, nymphs were exposed to 3:1, 1:1, and 1:3 DEET:IR3535 mixtures, and a synergistic effect was observed only in the CIPEIN colony.

  11. Long-term water repellency in organic olive orchards in the Cànyoles River watershed. The impact of land management

    Science.gov (United States)

    Cerdà, Artemi; González Pelayo, Óscar; García Orenes, Fuensanta; Jordán, Antonio; Pereira, Paulo; Novara, Agata; Neris, Jonay

    2015-04-01

    Soil water repellency is being researched in many enviroments of the world due to the fact that after two decades of intense investigations we found that soil water repellency is a soil property that can be found at any ecosystem (Atanassava and Doerr, 2011; Goebel et al., 2011; Mataix-Solera et al., 2013; Roper et al., 2013; Young et al., 2013; Badía-Villas et al., 2014; Jordán et al., 2014; Whelan et al., 2014). Soil water repellency inhibits or delays infiltration, encourage surface runoff but also the preferential flow in cracks and other macropores (Arye et al., 2011; Jordán et al., 2011; Madsen et al., 2011; Spohn and Rilling, 2012; García-Moreno et al., 2013; Hallin et al., 2013). Water repellency has been found in many soil types and it is present after forest fire, on forested land and also in agriculture soils (Granjed et al., 2013; Bodí et al., 2012; García Orenes et al., 2013; Jordán et al., 2012; Bodí et al., 2013; Dlapa et al., 2013; González-Peñaloza et al., 2012; López Garrido et al., 2012; León et al., 2013; Hewelke et al., 2014; Santos et al., 2014; Kröpfl et al., 2013). This paper show the measurements caried out by means of the water drop penetration time (WDPT) method in olive plantation in the Cànyoles watershed in Eastern Spain. Conservation practices applied such as no-tillage, manure addition, application of herbicides may contribute to increase soil organic matter and, hence, soil water repellency, and this is unknow under Mediterranean type ecosystems. The effect of long-term addition of plant residues and organic manure, no-tillage and no chemical fertilization (MNT), annual addition of plant residues and no-tillage (NT), application of conventional herbicides and no-tillage (H), and conventional tillage (CT) on soil water repellency in Mediterranean calcareous citrus-cropped soils (Eastern Spain) has been studied. Water repellency was observed in MNT soils, which may be attributed to the input of hydrophobic organic

  12. Composition and repellency of the essential oils of Evodia calcicola Chun ex Huang and Evodia trichotoma (Lour.) Pierre against three stored product insects.

    Science.gov (United States)

    Yang, Kai; You, Chun-Xue; Wang, Cheng-Fang; Guo, Shan-Shan; Li, Yin-Ping; Wu, Yan; Geng, Zhu-Feng; Deng, Zhi-Wei; Du, Shu-Shan

    2014-01-01

    During our screening program for agrochemicals from Chinese medicinal herbs and wild plants, the essential oils of Evodia calcicola and Evodia trichotoma leaves were found to possess strong repellency against the red flour beetle Tribolium castaneum adults, the cigarette beetle Lasioderma serricorne adults and the booklouse Liposcelis bostrychophila. The two essential oils obtained by hydrodistillation were investigated by GC-MS. The main components of E. calcicola essential oil were identified to be (-)-β-pinene (44.02%), β-phellandrene (20.93%), ocimene (16.49%), and D-limonene (9.87%). While the main components of the essential oil of E. trichotoma were D-limonene (69.55%), 1R-a-pinene (11.48%), caryophyllene (2.80%) and spathulenol (2.24%). Data showed that T. castaneum was the most sensitive than other two stored product insects. Compared with the positive control, DEET (N, N-diethyl-3- methylbenzamide), the two essential oils showed the same level repellency against the red flour beetle. However, the essential oil of E. trichotoma showed the same level repellency against the cigarette beetle, while E. calcicola essential oil possessed the less level repellency against L. serricorne, relative to the positive control, DEET. Moreover, the two crude oils also exhibited strong repellency against L. bostrychophila, but lesser level repellency than the positive control, DEET. Thus, the essential oils of E. calcicola and E. trichotoma may be potential to be developed as a new natural repellent in the control of stored product insects.

  13. Measuring and understanding soil water repellency through novel interdisciplinary approaches

    Science.gov (United States)

    Balshaw, Helen; Douglas, Peter; Doerr, Stefan; Davies, Matthew

    2017-04-01

    Food security and production is one of the key global issues faced by society. It has become evermore essential to work the land efficiently, through better soil management and agronomy whilst protecting the environment from air and water pollution. The failure of soil to absorb water - soil water repellency - can lead to major environmental problems such as increased overland flow and soil erosion, poor uptake of agricultural chemicals and increased risk of groundwater pollution due to the rapid transfer of contaminants and nutrient leaching through uneven wetting and preferential flow pathways. Understanding the causes of soil hydrophobicity is essential for the development of effective methods for its amelioration, supporting environmental stability and food security. Organic compounds deposited on soil mineral or aggregate surfaces have long been recognised as a major factor in causing soil water repellency. It is widely accepted that the main groups of compounds responsible are long-chain acids, alkanes and other organic compounds with hydrophobic properties. However, when reapplied to sands and soils, the degree of water repellency induced by these compounds and mixtures varied widely with compound type, amount and mixture, in a seemingly unpredictable way. Our research to date involves two new approaches for studying soil wetting. 1) We challenge the theoretical basis of current ideas on the measured water/soil contact angle measurements. Much past and current discussion involves Wenzel and Cassie-Baxter models to explain anomalously high contact angles for organics on soils, however here we propose that these anomalously high measured contact angles are a consequence of the measurement of a water drop on an irregular non-planar surface rather than the thermodynamic factors of the Cassie-Baxter and Wenzel models. In our analysis we have successfully used a much simpler geometric approach for non-flat surfaces such as soil. 2) Fluorescent and phosphorescent

  14. Laboratory and field evaluation of the impact of exercise on the performance of regular and polymer-based deet repellents.

    Science.gov (United States)

    Schofield, Steven; Tepper, Martin; Gadawski, Randy

    2007-11-01

    Studies were done in Manitoba, Canada, to evaluate the impact of exercise on repellent performance against mosquitoes. Two products containing the active ingredient N,N-diethyl-3-methylbenzamide (deet) were tested; one product was a polymer-based cream (3M Ultrathon Insect Repellent) and the other product was an alcohol-based pump spray formulation (Muskol Insect Repellent). Assessments were done in the laboratory using Aedes aegypti (L.) and in the field with naturally occurring populations of mosquitoes. Repellent was applied to the forearms (laboratory) or a lower leg (field) of test subjects at 1.5 g of test product per 600 cm2 surface area (0.75 or 0.83 mg deet/cm2). For a given test day, subjects exercised or did not. Exposure to mosquito attack was for 1 min at 30-min intervals in laboratory procedures, and it was continuous in field tests. Performance was measured as complete protection time (CPT). Moderate levels of physical activity resulted in a >40% decline in mean CPT, from 468 to 267 min in the laboratory experiments and from 359 to 203 min in field tests. Repellent product did not affect the magnitude of the decline. Mean biting pressure during field trials was 21.3 bites per min, and mosquito collections were made up primarily of Ochlerotatus sticticus (Meigen) and Aedes vexans (Meigen).

  15. Age structure, blood-feeding behavior, and Leishmania chagasi infection in Lutzomyia longipalpis (Diptera: Psychodidae) at an endemic focus of visceral leishmaniasis in Colombia.

    Science.gov (United States)

    Ferro, C; Morrison, A C; Torres, M; Pardo, R; Wilson, M L; Tesh, R B

    1995-09-01

    Ecological studies on the sand fly Lutzomyia longipalpis (Lutz & Neiva) were conducted during 1990-1992 in a small rural community in Colombia where American visceral leishmaniasis (AVL) is endemic. Subsamples of sand flies collected weekly from pigpens, the interior of houses, and natural outdoor resting sites were dissected to determine physiological age and Leishmania chagasi Cunha & Chagas infection rates. Eleven female L. longipalpis had flagellates in their gut, 2 of which were successfully cultured and identified as Leishmania chagasi. The reproductive status, stage of ovarian development, and trophic history of female sand flies varied among sites, habitats, and time of collection. The percentage of parous females ranged from about one-third to two-thirds overall and varied seasonally. Of most relevance to AVL transmission was the finding that 8% of L. longipalpis females were multiparous. In addition, our data suggest that L. longipalpis rest inside houses after blood-feeding outdoors, and that this species can blood-feed more than once during a single gonotrophic cycle.

  16. Prevention of infectious tick-borne diseases in humans: Comparative studies of the repellency of different dodecanoic acid-formulations against Ixodes ricinus ticks (Acari: Ixodidae

    Directory of Open Access Journals (Sweden)

    Dautel Hans

    2008-04-01

    Full Text Available Abstract Background Ticks of the species Ixodes ricinus are the main vectors of Lyme Borreliosis and Tick-borne Encephalitis – two rapidly emerging diseases in Europe. Repellents provide a practical means of protection against tick bites and can therefore minimize the transmission of tick-borne diseases. We developed and tested seven different dodecanoic acid (DDA-formulations for their efficacy in repelling host-seeking nymphs of I. ricinus by laboratory screening. The ultimately selected formulation was then used for comparative investigations of commercially available tick repellents in humans. Methods Laboratory screening tests were performed using the Moving-object (MO bioassay. All test formulations contained 10% of the naturally occurring active substance DDA and differed only in terms of the quantitative and qualitative composition of inactive ingredients and fragrances. The test procedure used in the human bioassays is a modification of an assay described by the U.S. Environmental Protection Agency and recommended for regulatory affairs. Repellency was computed using the equation: R = 100 - NR/N × 100, where NR is the number of non-repelled ticks, and N is the respective number of control ticks. All investigations were conducted in a controlled laboratory environment offering standardized test conditions. Results All test formulations strongly repelled nymphs of I. ricinus (100-81% protection as shown by the MO-bioassay. The majority of ticks dropped off the treated surface of the heated rotating drum that served as the attractant (1 mg/cm2 repellent applied. The 10% DDA-based formulation, that produced the best results in laboratory screening, was as effective as the coconut oil-based reference product. The mean protection time of both preparations was generally similar and averaged 8 hours. Repellency investigations in humans showed that the most effective 10% DDA-based formulation (~1.67 mg/cm2 applied strongly avoided the

  17. Repellency Effects of Essential Oils of Myrtle (Myrtus communis), Marigold (Calendula officinalis) Compared with DEET against Anopheles stephensi on Human Volunteers.

    Science.gov (United States)

    Tavassoli, M; Shayeghi, M; Abai, Mr; Vatandoost, H; Khoobdel, M; Salari, M; Ghaderi, A; Rafi, F

    2011-01-01

    Malaria and leishmaniasis are two most significant parasitic diseases which are endemic in Iran. Over the past decades, interest in botanical repellents has increased as a result of safety to human. The comparative efficacy of essential oils of two native plants, myrtle (Myrtus communis) and marigold (Calendula officinalis) collected from natural habitats at southern Iran was compared with DEET as synthetic repellent against Anopheles stephensi on human subjects under laboratory condition. Essential oils from two species of native plants were obtained by Clevenger-type water distillation. The protection time of DEET, marigold and myrtle was assessed on human subject using screened cage method against An. stephensi. The effective dose of 50% essential oils of two latter species and DEET were determined by modified ASTM method. ED(50) and ED(90) values and related statistical parameters were calculated by probit analysis. The protection time of 50% essential oils of marigold and myrtle were respectively 2.15 and 4.36 hours compared to 6.23 hours for DEET 25%. The median effective dose (ED(50)) of 50% essential oils was 0.1105 and 0.6034 mg/cm(2) respectively in myrtle and marigold. The figure for DEET was 0.0023 mg/cm(2). This study exhibited that the repellency of both botanical repellents was generally lower than DEET as a synthetic repellent. However the 50% essential oil of myrtle showed a moderate repellency effects compared to marigold against An. stephensi.

  18. Contact and Repellent Activities of the Essential Oil from Juniperus formosana against Two Stored Product Insects

    Directory of Open Access Journals (Sweden)

    Shanshan Guo

    2016-04-01

    Full Text Available The chemical composition of the essential oil from Juniperus formosana leaves and its contact and repellent activities against Tribolium castaneum and Liposcelis bostrychophila adults were investigated. The essential oil of J. formosana leaves was obtained by hydrodistillation and analyzed by GC-MS. A total of 28 components were identified and the main compounds in the essential oil were α-pinene (21.66%, 4-terpineol (11.25%, limonene (11.00% and β-phellandrene (6.63%. The constituents α-pinene, 4-terpineol and d-limonene were isolated from the essential oil. It was found that the essential oil exhibited contact activity against T. castaneum and L. bostrychophila adults (LD50 = 29.14 μg/adult and 81.50 µg/cm2, respectively. The compound 4-terpineol exhibited the strongest contact activity (LD50 = 7.65 μg/adult. In addition, data showed that at 78.63 nL/cm2, the essential oil and the three isolated compounds strongly repelled T. castaneum adults. The compounds α-pinene and d-limonene reached the same level (Class V of repellency as DEET (p = 0.396 and 0.664 against L. bostrychophila at 63.17 nL/cm2 after 2 h treatment. The results indicate that the essential oil and the isolated compounds have potential to be developed into natural insecticides and repellents to control insects in stored products.

  19. Screening of botanical extracts for repellence against western corn rootworm larvae

    Science.gov (United States)

    The ability of Western corn rootworm (WCR) to develop resistance to various management practices enforces the development of new control options. Repellent substances can act as efficacy enhancing agents in WCR control with biological control agents. The present study investigated the potential repe...

  20. Plant essential oils and potassium metabisulfite as repellents for Drosophila suzukii (Diptera: Drosophilidae)

    Science.gov (United States)

    Renkema, Justin M.; Wright, Derek; Buitenhuis, Rose; Hallett, Rebecca H.

    2016-01-01

    Spotted wing drosophila, Drosophila suzukii, is a globally invasive pest of soft-skinned fruit. Females oviposit into ripening fruit and larvae cause direct destruction of tissues. As many plant essential oils are permitted food additives, they may provide a safe means of protecting fruit from D. suzukii infestation in both conventional and organic production systems. Twelve oils and potassium metabisulfite (KMS) were screened in the laboratory as repellents for D. suzukii flies. Most essential oils deterred D. suzukii flies from cotton wicks containing attractive raspberry juice. Peppermint oil was particularly effective, preventing almost all flies from contacting treated wicks and remaining 100% repellent for 6 d post-application. Thyme oil was unique because it caused high male mortality and reduced the number of responding flies compared to other oils. KMS was not found to be repellent to D. suzukii, but may have fumigant properties, particularly at high concentrations. Peppermint oil appears to be the best candidate for field testing to determine the effectiveness and feasibility of using essential oils as part of a push-pull management strategy against D. suzukii. This is the first time that essential oils have been evaluated and proven effective in preventing fruit-infesting flies from contacting attractive stimuli. PMID:26893197

  1. The immunomodulatory protein RH36 is relating to blood-feeding success and oviposition in hard ticks.

    Science.gov (United States)

    Wang, Fangfang; Lu, Xiaojuan; Guo, Fengxun; Gong, Haiyan; Zhang, Houshuang; Zhou, Yongzhi; Cao, Jie; Zhou, Jinlin

    2017-06-15

    An immunomodulatory protein designated RH36 was identified in the tick Rhipicephalus haemaphysaloides. The cDNA sequence of RH36 has 844bp and encodes a deduced protein with a predicted molecular weight of 24kDa. Bioinformatics analysis indicated that RH36 presented a degree of similarity of 34.36% with the immunomodulatory protein p36 from the tick Dermacentor andersoni. The recombinant RH36 (rRH36) expressed in Sf9 insect cells suppressed the T-lymphocyte mitogen-driven in vitro proliferation of splenocytes and the expression of several cytokines such as IL-2, IL-12, and TNF-α. Furthermore, the proliferation of splenocytes isolated from rRH36-inoculated mice was significantly lower than that in control mice, suggesting that rRH36 could directly suppress immune responses in vivo. In addition, microarray analysis of splenocytes indicated that the expression of several immunomodulatory genes was downregulated by rRH36. The silencing of the RH36 gene by RNAi led to a 37.5% decrease in the tick attachment rate 24h after placement into the rabbit ears, whereas vaccination with RH36 caused a 53.06% decrease in the tick engorgement rate. Unexpectedly, RNAi induced a significant decrease in the oviposition rate, ovary weight at day 12 after engorgement, and egg-hatching rate. The effects of RH36 on blood feeding and oviposition were further confirmed by vaccination tests using the recombinant protein. These results indicate that RH36 is a novel member of immunosuppressant proteins and affects tick blood feeding and oviposition. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Feeding and defaecation patterns in Triatoma sordida

    Directory of Open Access Journals (Sweden)

    LB Crocco

    1996-08-01

    Full Text Available Triatoma sordida is a peridomestic Triatominae that could play an important role in the transmission of Trypanosoma cruzi, although its vectorial competence is not well known. The aim of this work was to evaluate two aspects of the vectorial competence: the feeding behaviour and defaecation patterns, and to compare them with T. infestans. The feeding and defaecation patterns were studied in adults and fifth instar nymphs of T. sordida fed ad libitum on a restrained pigeon. The results showed how the blood meal size controls excretion behaviour. Blood intake and time to first defaecation showed a significant negative correlation. Adults and nymphs frequently defaecated during the blood meal, reaching the maximum frequency within the first 10 minutes.

  3. Effect of dietary energy levels and phase feeding by protein levels on growth performance, blood profiles and carcass characteristics in growing-finishing pigs

    Directory of Open Access Journals (Sweden)

    J. S. Hong

    2016-10-01

    Full Text Available Abstract Background Providing of insufficient nutrients limits the potential growth of pig, while feeding of excessive nutrients increases the economic loss and causes environment pollution. For these reasons, phase feeding had been introduced in swine farm for improving animal production. This experiment was conducted to evaluate the effects of dietary energy levels and phase feeding by protein levels on growth performance, blood profiles and carcass characteristics in growing-finishing pigs. Methods A total of 128 growing pigs ([Yorkshire × Landrace] × Duroc, averaging 26.62 ± 3.07 kg body weight, were assigned in a 2 × 4 factorial arrangement with 4 pigs per pen. The first factor was two dietary energy level (3,265 kcal of ME/kg or 3,365 kcal of ME/kg, and the second factor was four different levels of dietary protein by phase feeding (1growing(G-2finishing(F phases, 2G-2F phases, 2G-3F phases and 2G-3F phases with low CP requirement. Results In feeding trial, there was no significant difference in growth performance. The BUN concentration was decreased as dietary protein level decreased in 6 week and blood creatinine was increased in 13 week when pigs were fed diets with different dietary energy level. The digestibility of crude fat was improved as dietary energy levels increased and excretion of urinary nitrogen was reduced when low protein diet was provided. Chemical compositions of longissimus muscle were not affected by dietary treatments. In backfat thickness (P2 at 13 week, pigs fed high energy diet had thicker backfat thickness (P = 0.06 and pigs fed low protein diet showed the trend of backfat thinness reduction (P = 0.09. In addition, water holding capacity was decreased (P = 0.01 and cooking loss was increased (P = 0.07 as dietary protein level reduced. When pigs were fed high energy diet with low subdivision of phase feeding, days to 120 kg market weight was reached earlier compared to

  4. Water repellent soils following prescribed burning treatments and a wildfire in the oak savannas of the Malpai Borderlands Region

    Science.gov (United States)

    Cody L. Stropki; Peter F. Ffolliott; Gerald J. Gottfried

    2009-01-01

    Water repellent (hydrophobic) soils impact the infiltration process of a water budget by restricting the movement of water into and through a soil body. The infiltration of water into a water repellent soil can be inhibited or completely impeded in which case much of the incoming precipitation reaching the soil surface becomes overland flow. One mechanism causing the...

  5. Evaluation of consolidating and water repellent treatments applied to the miocene sandstone used in Tunisian Heritage Monuments

    Directory of Open Access Journals (Sweden)

    Zoghlami, K.

    2005-03-01

    Full Text Available Summary The research reported in the present paper focused on the behaviour of the Miocene sandstone used to build the Roman aqueduct at Zaghouan-Carthage and other Tunisian Heritage monuments, after application of water repellent and consolidating treatments as a preliminary to restoration. Commercial consolidants and water repellents were used in the experiments: two ethyl silicate consolidants, Tegovakon (TV and Keim-Silex OH (KSOH; two (siloxane water repellents, Tegosivin THE 328 (THE and Tegosivin HLJ00 (THE; and a dual (consolidate and water repellent action substance, Keim- Silex H (KSH (silicate acid ester base with siloxane. A mixed treatment consisting of successive coats of TV and THL (TVHL was also applied. These organosilicate consolidants and water repellents acted on the porous structure of the sandstone, reducing total porosity and water vapour permeability. The water repellent THE was found to affect these properties least, with a pore size distribution that resembled the distribution in the untreated sandstone most closely. Water repellents diminish water absorption and consolidants increase mechanical strength. The TV-THL mix, which yielded results similar to those obtained with water repellents alone, was unable to prevent the substantial scaling that occurs during (RILEM salt crystallisation-induced artificial ageing. The best results were found with the dual action consolidant! water repellent product (KSH, which improved the mechanical properties while affording protection from the decay caused by salts in artificial ageing trials. This substance was found to reduce water vapour permeability, however

    Esta investigación se centra en la evaluación del comportamiento de la arenisca miocénica utilizada en el acueducto de Zaghouan-Cartago y otros monumentos del Patrimonio Monumental de Túnez tras la aplicación de tratamientos de hidrofugación y de consolidación. Para los tratamientos se han seleccionado productos

  6. Near-surface distributions of soil water and water repellency under three effluent irrigation scemes in a blue gum (Eucalyptus globulus) plantation

    NARCIS (Netherlands)

    Thwaites, L.A.; Rooij, de G.H.; Salzman, S.; Allinson, G.; Stagnitti, F.; Carr, R.; Versace, V.; Struck, S.; March, T.

    2006-01-01

    Water repellent soils are difficult to irrigate and susceptible to preferential flow, which enhances the potential for accelerated leaching to groundwater of hazardous substances. Over 5 Mha of Australian soil is water repellent, while treated municipal sewage is increasingly used for irrigation.

  7. Insecticidal and repellent effects of tea tree and andiroba oils on flies associated with livestock.

    Science.gov (United States)

    Klauck, V; Pazinato, R; Stefani, L M; Santos, R C; Vaucher, R A; Baldissera, M D; Raffin, R; Boligon, A; Athayde, M; Baretta, D; Machado, G; DA Silva, A S

    2014-08-01

    This study aimed to evaluate the insecticidal and repellent effects of tea tree, Melaleuca alternifolia (Myrtales: Myrtaceae), and andiroba, Carapa guianensis (Sapindales: Meliaceae), essential oils on two species of fly. For in vitro studies, free-living adult flies were captured and reared in the laboratory. To evaluate the insecticidal effects of the oils, adult flies of Haematobia irritans (L.) and Musca domestica L. (both: Diptera: Muscidae) were separated by species in test cages (n = 10 per group), and subsequently tested with oils at concentrations of 1.0% and 5.0% using a negative control to validate the test. Both oils showed insecticidal activity. Tea tree oil at a concentration of 5.0% was able to kill M. domestica with 100.0% efficacy after 12 h of exposure. However, the effectiveness of andiroba oil at a concentration of 5.0% was only 67.0%. The insecticidal efficacy (100.0%) of both oils against H. irritans was observed at both concentrations for up to 4 h. The repellency effects of the oils at concentrations of 5.0% were tested in vivo on Holstein cows naturally infested by H. irritans. Both oils demonstrated repellency at 24 h, when the numbers of flies on cows treated with tea tree and andiroba oil were 61.6% and 57.7%, respectively, lower than the number of flies on control animals. It is possible to conclude that these essential oils have insecticidal and repellent effects against the species of fly used in this study. © 2014 The Royal Entomological Society.

  8. Nutritional Value of Irradiated Animal Feed By-Products

    International Nuclear Information System (INIS)

    El-Din Farag, M.D.H.

    1998-01-01

    Animal feed by-products, widely used in animal diets, are sources of disease organisms for animals and for human beings. Salmonella is the principal genus of concern.Radiation treatment (radicidation, radurization) is a promising method of decontamination of feed ingredients. Commercial samples of fish, meat, and blood meals were sealed by heat in polyethylene bags and irradiated at dose levels of 5.0, 10, 20 and 50 kGy. Their chemical analysis were carried out according to A. O. A.C [1] and the total protein efficiency (TPE) of the three animal feed by-products was determined according to Wood ham (2) by using one day old Dokki-4 chicks. Radiation induced an insignificant effect on the chemical constituent of meals. Also, the same trend was observed with TPE of both fish and meat meals. However, irradiation treatments improved TPE values of irradiated blood meal samples. From the results, it could be concluded that irradiation of animal feed by-products up to a dose level of 50 Gy has no adverse effects on the nutritional value of animal feed by-products

  9. Vegetation cover and land use impacts on soil water repellency in an Urban Park located in Vilnius, Lithuania

    Science.gov (United States)

    Pereira, Paulo; Cerda, Artemi

    2015-04-01

    It is strongly recognized that vegetation cover, land use have important impacts on the degree of soil water repellency (SWR). Soil water repellency is a natural property of soils, but can be induced by natural and anthropogenic disturbances as fire and soil tillage (Doerr et al., 2000; Urbanek et al., 2007; Mataix-Solera et al., 2014). Urban parks are areas where soils have a strong human impact, with implications on their hydrological properties. The aim of this work is to study the impact of different vegetations cover and urban soils impact on SWR and the relation to other soil variables as pH, Electrical Conductivity (EC) and soil organic matter (SOM) in an urban park. The study area is located in Vilnius city (54°.68' N, 25°.25' E). It was collected 15 soil samples under different vegetation cover as Pine (Pinus Sylvestris), Birch (Alnus glutinosa), Penduculate Oak (Quercus robur), Platanus (Platanus orientalis) and other human disturbed areas as forest trails and soils collected from human planted grass. Soils were taken to the laboratory, air-dried at room temperature and sieved with the 3600 (extremely water repellent). The results showed significant differences among the different vegetation cover (Kruskal-Wallis H=20.64, ppost-fire management scenarios, CGL2013-47862-C2-1-R), funded by the Spanish Ministry of Economy and Competitiveness; Fuegored; RECARE (Preventing and Remediating Degradation of Soils in Europe Through Land Care, FP7-ENV-2013-TWO STAGE), funded by the European Commission; and for the COST action ES1306 (Connecting European connectivity research). References Bisdom, E.B.A., Dekker, L., Schoute, J.F.Th. (1993) Water repellency of sieve fractions from sandy soils and relationships with organic material and soil structure. Geoderma, 56, 105-118. Doerr, S.H., Shakesby, R.A., Walsh, R.P.D. (2000) Soil water repellency: Its causes, characteristics and hydro-geomorphological significance. Earth-Science Reviews, 51, 33-65. Doerr, S.H. (1998

  10. Repellency Effects of Essential Oils of Myrtle (Myrtus communis, Marigold (Calendula officinalis Compared with DEET against Anopheles stephensi on Human Volunteers

    Directory of Open Access Journals (Sweden)

    M Tavassoli

    2011-12-01

    Full Text Available Background: Malaria and leishmaniasis are two most significant parasitic diseases which are endemic in Iran. Over the past decades, interest in botanical repellents has increased as a result of safety to human. The comparative effi­cacy of essential oils of two native plants, myrtle (Myrtus communis and marigold (Calendula officinalis collected from natural habitats at southern Iran was compared with DEET as synthetic repellent against Anopheles stephensi on human subjects under laboratory condition. Methods:  Essential oils from two species of native plants were obtained by Clevenger-type water distillation. The protec­tion time of DEET, marigold and myrtle was assessed on human subject using screened cage method against An. stephensi. The effective dose of 50% essential oils of two latter species and DEET were determined by modified ASTM method. ED50 and ED90 values and related statistical parameters were calculated by probit analysis.   Results: The protection time of 50% essential oils of marigold and myrtle were respectively 2.15 and 4.36 hours com­pared to 6.23 hours for DEET 25%. The median effective dose (ED50 of 50% essential oils was 0.1105 and 0.6034 mg/cm2 respectively in myrtle and marigold. The figure for DEET was 0.0023 mg/cm2. Conclusion: This study exhibited that the repellency of both botanical repellents was generally lower than DEET as a synthetic repellent. However the 50% essential oil of myrtle showed a moderate repellency effects compared to mari­gold against An. stephensi.

  11. Repellency Effects of Essential Oils of Myrtle (Myrtus Communis, Marigold (Calendula Officinalis Compared with DEET Against Anopheles Stephensi on Human Volunteers

    Directory of Open Access Journals (Sweden)

    M Khoobdel

    2011-12-01

    Full Text Available Background: Malaria and leishmaniasis are two most significant parasitic diseases which are endemic in Iran. Over the past decades, interest in botanical repellents has increased as a result of safety to human. The comparative effi­cacy of essential oils of two native plants, myrtle (Myrtus communis and marigold (Calendula officinalis collected from natural habitats at southern Iran was compared with DEET as synthetic repellent against Anopheles stephensi on human subjects under laboratory condition. Methods: Essential oils from two species of native plants were obtained by Clevenger-type water distillation. The protec­tion time of DEET, marigold and myrtle was assessed on human subject using screened cage method against An. stephensi. The effective dose of 50% essential oils of two latter species and DEET were determined by modified ASTM method. ED50 and ED90 values and related statistical parameters were calculated by probit analysis. Results: The protection time of 50% essential oils of marigold and myrtle were respectively 2.15 and 4.36 hours com­pared to 6.23 hours for DEET 25%. The median effective dose (ED50 of 50% essential oils was 0.1105 and 0.6034 mg/cm2 respectively in myrtle and marigold. The figure for DEET was 0.0023 mg/cm2.Conclusion: This study exhibited that the repellency of both botanical repellents was generally lower than DEET as a synthetic repellent. However the 50% essential oil of myrtle showed a moderate repellency effects compared to mari­gold against An. stephensi.

  12. Preventing Superinfection in Malaria Spreads with Repellent and Medical Treatment Policy

    Science.gov (United States)

    Fitri, Fanny; Aldila, Dipo

    2018-03-01

    Malaria is a kind of a vector-borne disease. That means this disease needs a vector (in this case, the anopheles mosquito) to spread. In this article, a mathematical model for malaria disease spread will be discussed. The model is constructed as a seven-dimensional of a non-linear ordinary differential equation. The interventions of treatment for infected humans and use of repellent are included in the model to see how these interventions could be considered as alternative ways to control the spread of malaria. Analysis will be made of the disease-free equilibrium point along with its local stability criteria, construction of the next generation matrix which followed with the sensitivity analysis of basic reproduction number. We found that both medical treatment and repellent intervention succeeded in reducing the basic reproduction number as the endemic indicator of the model. Finally, some numerical simulations are given to give a better interpretation of the analytical results.

  13. The effects of increasing garlic powder and monensin supplementation on feed intake, nutrient digestibility, growth performance and blood parameters of growing calves.

    Science.gov (United States)

    Gholipour, A; Foroozandeh Shahraki, A D; Tabeidian, S A; Nasrollahi, S M; Yang, W Z

    2016-08-01

    The objective of this study was to evaluate the effects of increasing garlic powder and monensin supplementation on feed intake, nutrient digestibility, growth performance and blood metabolites of growing calves. Forty Holstein calves (BW = 100 ± 11 kg) were randomly assigned to four dietary treatments (n = 10) in a complete randomized design. Experimental treatments consisted of the following: (i) basal diet (control), (ii) basal diet supplemented with 0.0003% of dietary dry matter (DM) sodium monensin, (iii) low level of garlic powder (Low-GAR; 0.5% of dietary DM) and (iv) high level of garlic powder (High-GAR; 1% of dietary DM). DM intake (DMI) and DM digestibility were (p calves supplemented with Low-GAR had a similar DMI to the control calves and similar DM digestibility to the control and monensin groups. The digestibility of other nutrients were not affected by the treatments. Although supplementing monensin relative to Low-GAR increased the DMI (p calves, which were higher than the control and High-GAR groups (p feed conversion ratio was improved in the Low-GAR group versus other treatment groups (p calves fed the Low-GAR showed an improved FCR and blood metabolites without changing the DMI and nutrient digestibility. It suggests that garlic powder could be used as an alternative to monensin for growing calves under the current feeding conditions. Journal of Animal Physiology and Animal Nutrition © 2015 Blackwell Verlag GmbH.

  14. Field trial on the spatial repellency of metofluthrin-impregnated plastic strips for mosquitoes in shelters without walls (beruga) in Lombok, Indonesia.

    Science.gov (United States)

    Kawada, Hitoshi; Maekawa, Yoshihide; Takagi, Masahiro

    2005-12-01

    Field trials on the spatial repellency of metofluthrin-impregnated plastic strips for mosquitoes present in shelters without walls (beruga) were carried out in Lombok, Indonesia. A major reduction in the incidence of human biting by Culex quinquefasciatus was achieved, and the use of two strips per beruga repelled >60% of the mosquitoes for at least 11 wk while four strips repelled >60% of the mosquitoes for more than 15 weeks. The technique was found to be a practical long-term solution for the prevention of mosquito bites without using electricity or heat to evaporate the metofluthrin.

  15. Repellent effectiveness of seven plant essential oils, sunflower oil and natural insecticides against horn flies on pastured dairy cows and heifers.

    Science.gov (United States)

    Lachance, S; Grange, G

    2014-06-01

    Plant essential oils (basil, geranium, balsam fir, lavender, lemongrass, peppermint, pine and tea tree), mixed with either sunflower oil or ethyl alcohol, were applied at 5% concentrations to the sides of Holstein cattle. Pastured cattle treated with essential oils diluted in sunflower oil had less flies than the untreated control for a 24-h period. However, the essential oil treatments were not significantly different than the carrier oil alone. Barn-held heifers treated with essential oils and sunflower oil alone had significantly less flies than the untreated control for up to 8 h after treatment. Basil, geranium, lavender, lemongrass and peppermint repelled more flies than sunflower oil alone for a period ranging from 1.5 to 4 h after treatments applied to heifers. All essential oils repelled > 75% of the flies on the treated area for 6 and 8 h on pastured cows and indoor heifers, respectively. Geranium, lemongrass and peppermint stayed effective for a longer duration. Essential oils mixed with ethyl alcohol demonstrated less repellence than when mixed with the carrier oil. Safer's soap, natural pyrethrins without piperonyl butoxide and ethyl alcohol alone were not efficient at repelling flies. Essential oils could be formulated for use as fly repellents in livestock production. © 2013 The Royal Entomological Society.

  16. Creams formulated with Ocimum gratissimum L. and Lantana camara L. crude extracts and fractions as mosquito repellents against Aedes aegypti L. (Diptera: Culicidae).

    Science.gov (United States)

    Keziah, Ezeike Amarachi; Nukenine, Elias Nchiwan; Danga, Simon Pierre Yinyang; Younoussa, Lame; Esimone, Charles Okechukwu

    2015-01-01

    Mosquitoes are the most deadly vectors of parasites that cause diseases such as malaria, yellow fever, and filariasis. In view of the recent increased interest in developing plant origin insecticides as an alternative to chemical insecticides, the objective of this study was to determine the repellent activity of creams formulated with methanol crude extract (MCE), hexane fraction (HF), and ethyl acetate fractions (EAFs) of Ocimum gratissimum and Lantana camara leaves in single and combined actions against female Aedes aegypti. Evaluation was carried out in the net cages (30 by 30 by 30 cm) containing 60 blood-starved female mosquitoes each and were assayed in the laboratory condition following World Health Organization 2009 protocol. All formulations (single and mixture) were applied at 2, 4, 6, and 8 mg/cm(2) in the exposed area of human hands. Only acetone + white soft paraffin served as negative control and odomos (12% DEET) as positive control. All the formulations presented good protection against mosquito bites without any allergic reaction by the human volunteers. The repellent activity was dependent on the strength of the extracts and fractions. Among the tested formulations, the maximum protection time was observed in MCE (120 min) and EAF (150 min) of O. gratissimum; MCE:MCE (150 min) and HF:HF (120 min) mixtures of both plants. In addition, MCE:MCE and HF:HF mixtures from both plants showed possible synergistic effect. From the results, the combination of O. gratissimum and L. camara to formulate natural mosquito repellent using small amount of extracts can be encouraging to be an alternative to conventional DEET. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

  17. Insecticidal and Repellent Activit ies of Laurinterol from the Okinawan Red Alga Laurencia nidifica

    Directory of Open Access Journals (Sweden)

    Takahiro Ishii

    2017-01-01

    Full Text Available An ethyl acetate (EtOAc extract of Laurencia nidifica was found to have toxic effect against brine shrimp larvae (Artemia salina. Bioassay-guided fractionation of the EtOAc extract resulted in the isolation of four known halogenated sesquiterpenes, laurinterol (1, isolaurinterol (2, aplysin (3, and a -bromocuparene (4. Their structures were established on the basis of spectral analysis and comparison with literature data. Among isolated compounds, only laurinterol showed strong toxicity against A. salina. Further experiments revealed that laurinterol also exhibited repellent activity against the maize weevil Sitophilus zeamais , insecticidal activity against the termite Reticulitermes speratus, and acetylcholinesterase (AChE inhibitory effect . This is the first report of insecticidal and repellent activities of laurinterol.

  18. Effect of Unripe Plantain (Musa paradisiaca) and Ginger (Zingiber officinale) on Blood Glucose, Body Weight and Feed Intake of Streptozotocin-induced Diabetic Rats.

    Science.gov (United States)

    M, Iroaganachi; C O, Eleazu; P N, Okafor; N, Nwaohu

    2014-01-01

    To determine the effect of unripe plantain (Musa paradisiaca) and ginger (Zingiber officinale) on blood glucose (BG), feed intake (FI) and weight of streptozotocin (STZ) induced diabetic rats. Twenty four male albino rats were used and were divided into 4 groups of 6 rats each. Group 1 (non-diabetic) and Group 2 (diabetic) received standard rat feed; Group 3 received unripe plantain incorporated feed (810 /kg body weight) and Group 4 received unripe plantain+ginger incorporated feed (710:100 g/kg body weight). The weights and FI of the rats were measured daily throughout the experimentation. Groups 3 and 4 rats had 159.52% and 71.83% decreases in BG but 24.91% and 35.32% decreases in weights compared with groups 1 and 2 rats that had 2.09% and 22.94% increases in BG with 13.42% increase and 45.36% decrease in weights respectively. The FI of the experimental rats did not differ significantly from each other (P>0.05) at the end of experimentation. The standard rat feed contained higher amounts of Ca but lower amounts of Mg and Fe compared with the unripe plantain and unripe plantain+ginger incorporated feeds. Combination of unripe plantain and ginger at the dose used in the management of diabetes was not very effective compared with unripe plantain alone.

  19. Structure and ligand-binding properties of the biogenic amine-binding protein from the saliva of a blood-feeding insect vector of Trypanosoma cruzi

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xueqing; Chang, Bianca W. [NIH/NIAID, 12735 Twinbrook Parkway, Rockville, MD 20852 (United States); Mans, Ben J. [NIH/NIAID, 12735 Twinbrook Parkway, Rockville, MD 20852 (United States); Agricultural Research Council, Onderstepoort 0110 (South Africa); Ribeiro, Jose M. C.; Andersen, John F., E-mail: jandersen@niaid.nih.gov [NIH/NIAID, 12735 Twinbrook Parkway, Rockville, MD 20852 (United States)

    2013-01-01

    Biogenic amine-binding proteins mediate the anti-inflammatory and antihemostatic activities of blood-feeding insect saliva. The structure of the amine-binding protein from R. prolixus reveals the interaction of biogenic amine ligands with the protein. Proteins that bind small-molecule mediators of inflammation and hemostasis are essential for blood-feeding by arthropod vectors of infectious disease. In ticks and triatomine insects, the lipocalin protein family is greatly expanded and members have been shown to bind biogenic amines, eicosanoids and ADP. These compounds are potent mediators of platelet activation, inflammation and vascular tone. In this paper, the structure of the amine-binding protein (ABP) from Rhodnius prolixus, a vector of the trypanosome that causes Chagas disease, is described. ABP binds the biogenic amines serotonin and norepinephrine with high affinity. A complex with tryptamine shows the presence of a binding site for a single ligand molecule in the central cavity of the β-barrel structure. The cavity contains significant additional volume, suggesting that this protein may have evolved from the related nitrophorin proteins, which bind a much larger heme ligand in the central cavity.

  20. Structure and ligand-binding properties of the biogenic amine-binding protein from the saliva of a blood-feeding insect vector of Trypanosoma cruzi

    International Nuclear Information System (INIS)

    Xu, Xueqing; Chang, Bianca W.; Mans, Ben J.; Ribeiro, Jose M. C.; Andersen, John F.

    2013-01-01

    Biogenic amine-binding proteins mediate the anti-inflammatory and antihemostatic activities of blood-feeding insect saliva. The structure of the amine-binding protein from R. prolixus reveals the interaction of biogenic amine ligands with the protein. Proteins that bind small-molecule mediators of inflammation and hemostasis are essential for blood-feeding by arthropod vectors of infectious disease. In ticks and triatomine insects, the lipocalin protein family is greatly expanded and members have been shown to bind biogenic amines, eicosanoids and ADP. These compounds are potent mediators of platelet activation, inflammation and vascular tone. In this paper, the structure of the amine-binding protein (ABP) from Rhodnius prolixus, a vector of the trypanosome that causes Chagas disease, is described. ABP binds the biogenic amines serotonin and norepinephrine with high affinity. A complex with tryptamine shows the presence of a binding site for a single ligand molecule in the central cavity of the β-barrel structure. The cavity contains significant additional volume, suggesting that this protein may have evolved from the related nitrophorin proteins, which bind a much larger heme ligand in the central cavity

  1. Moment analysis description of wetting and redistribution plumes in wettable and water-repellent soils

    Science.gov (United States)

    Xiong, Yunwu; Furman, Alex; Wallach, Rony

    2012-02-01

    SummaryWater repellency has a significant impact on water flow patterns in the soil profile. Transient 2D flow in wettable and natural water-repellent soils was monitored in a transparent flow chamber. The substantial differences in plume shape and spatial water content distribution during the wetting and subsequent redistribution stages were related to the variation of contact angle while in contact with water. The observed plumes shape, internal water content distribution in general and the saturation overshoot behind the wetting front in particular in the repellent soils were associated with unstable flow. Moment analysis was applied to characterize the measured plumes during the wetting and subsequent redistribution. The center of mass and spatial variances determined for the measured evolving plumes were fitted by a model that accounts for capillary and gravitational driving forces in a medium of temporally varying wettability. Ellipses defined around the stable and unstable plumes' centers of mass and whose semi-axes represented a particular number of spatial variances were used to characterize plume shape and internal moisture distribution. A single probability curve was able to characterize the corresponding fractions of the total added water in the different ellipses for all measured plumes, which testify the competence and advantage of the moment analysis method.

  2. Transport of water and solutes in wettable and water repellent sandy soils

    NARCIS (Netherlands)

    Ritsema, C.J.; Dekker, L.W.

    1996-01-01

    The research yielded the following conclusions and results: preferential flow can be expected in recently deposited, loosely packed, wettable dune sands; preferential flow is common in most water-repellent sandy soils; distribution flow in topsoils isa process of major importance, resulting in a

  3. Soil-Water Repellency Characteristic Curves for Soil Profiles with Organic Carbon Gradients

    DEFF Research Database (Denmark)

    Wijewardana, Nadeeka Senani; Muller, Karin; Moldrup, Per

    2016-01-01

    Soil water repellency (SWR) of soils is a property with significant consequences for agricultural water management, water infiltration, contaminant transport, and for soil erosion. It is caused by the presence of hydrophobic agents on mineral grain surfaces. Soils were samples in different depths......, and the sessile drop method (SDM). The aim to (i) compare the methods, (ii) characterize the soil-water repellency characteristic curves (SWRCC) being SWR as a function of the volumetric soil-water content (θ) or matric potential (ψ), and (iii) find relationships between SWRCC parameters and SOC content. The WDPT...... at three forest sites in Japan and three pasture sites in New Zealand, covering soil organic carbon (SOC) contents between 1 and 26%. The SWR was measured over a range of water contents by three common methods; the water drop penetration time (WDPT) test, the molarity of an ethanol droplet (MED) method...

  4. Glycaemic and insulinaemic responses of adult healthy warm-blooded mares following feeding with Jerusalem artichoke meal.

    Science.gov (United States)

    Glatter, M; Bochnia, M; Goetz, F; Gottschalk, J; Koeller, G; Mielenz, N; Hillegeist, D; Greef, J M; Einspanier, A; Zeyner, A

    2017-06-01

    This study aimed to investigate the impact of the supplementation of a pre-biotic compound [Jerusalem artichoke meal (JAM)] on the glycaemic and insulinaemic response in healthy, non-obese warm-blooded horses. Six adult mares [mean body weight (bwt) 529 ± 38.7 kg; body condition score 5.1 ± 0.49/9] were used. In two equal meals per day, the horses received crushed oat grains (1 g starch/kg bwt per day) and meadow hay (2 kg/100 kg bwt per day) which together were likely to meet the energy recommendation for light work (GfE, ). Additionally, they received either 0.15 g fructo-oligosaccharides and inulin (FOS+INU)/kg bwt per day via commercial JAM or maize cob meal without grains as control (CON) in 2 × 3-week periods according to a crossover design. Blood was collected on d21 of the feeding period at different ante- and postprandial (PP) time points (-60, 0, 30, 60, 90, 120, 180, 240 and 300 min), and the plasma glucose and serum insulin levels were determined. Feeding JAM vs. CON did not change the PP peak of glucose or insulin (glucose: 6.3 ± 0.40 vs. 7.0 ± 0.87 mmol/l; insulin: 0.508 ± 0.087 vs. 0.476 ± 0.082 nmol/l) nor did it cause different AUCs until 120 and 300 min PP for glucose and insulin, respectively (AUC 120 , glucose: 997 ± 41.6 vs. 1015 ± 41.63 mmol/l per minute, insulin: 49 ± 6.3 vs. 42 ± 6.3 nmol/l per minute; AUC 300 , glucose: 1943 ± 142.3 vs. 2115 ± 142.3 mmol/l per minute, insulin: 94 ± 14.8 vs. 106 ± 14.8 nmol/l per minute; p > 0.05). Following JAM vs. CON feeding, glucose and insulin levels declined more rapidly until 240 min PP and tended to be lower (p = 0.053 and p = 0.056, respectively) at this time point. This result might be promising and should further be studied more detailed. Journal of Animal Physiology and Animal Nutrition © 2017 Blackwell Verlag GmbH.

  5. Repellency of Lantana camara (Verbenaceae) flowers against Aedes mosquitoes.

    Science.gov (United States)

    Dua, V K; Gupta, N C; Pandey, A C; Sharma, V P

    1996-09-01

    The repellent effect of Lantana camara flowers was evaluated against Aedes mosquitoes. Lantana flower extract in coconut oil provided 94.5% protection from Aedes albopictus and Ae. aegypti. The mean protection time was 1.9 h. One application of Lantana flower can provide more than 50% protection up to 4 h against the possible bites of Aedes mosquitoes. No adverse effects of the human volunteers were observed through 3 months after the application.

  6. Chemical composition of essential oils of Drimys angustifolia Miers and Drimys brasiliensis Miers and their repellency to drywood termite Cryptotermes brevis (Isoptera: Kalotermitidae

    Directory of Open Access Journals (Sweden)

    Madson Ralide Fonseca Gomes

    2014-01-01

    Full Text Available The essential oils extracted from leaves of the Southern Brazilian native species Drimys angustifolia Miers (DA and Drimys brasiliensis Miers (DB by Clevenger distillation were analyzed by gas chromatography/ mass spectrometry (GC/MS. The oils of DA and DB consisted predominantly of monoterpenoids and sesquiterpenoids. The largest components of DA oil were bicyclogermacrene (19.6%, sabinene (9.7% and myrcene (5.2%, while DB oil was characterized by cyclocolorenone (18.2%, followed by terpinen-4- ol (8.7% and alpha-gurjunene (6.9%. Laboratory tests were carried out to determine the repellency of the essential oils to the drywood termite Cryptotermes brevis (Isoptera: Kalotermitidae. It was observed that the oil showed repellency at the concentrations 25, 12.5, and 6.25 μg/mL. The oils of both species exhibited a negative repellency index, which represents repellent activity, except for DA oil at the highest concentration, which was attractive. Five deaths (11% of the termite sample were observed at 25 μg/mL DA, in the fourhour repellency test, while four deaths occurred at 12.5 μg/mL (approximately 9%. The essential oil of DB did not cause any termite deaths.

  7. Pharyngeal cavity and the gills are the target organ for the repellent action of pardaxin in shark.

    Science.gov (United States)

    Primor, N

    1985-05-15

    Pardaxin, an active principle of the repellent secretion of the Red Sea flatfish, Pardachirus marmoratus, elicited severe struggling, mouth paralysis, and transient increase in urea leakage from the gills only when administered to the medium bathing the shark's pharyngeal cavity and gills. An apparatus was constructed which prevents a mixing of the outflow from shark's gills with water bathing its surface skin. It is concluded that in sharks the gills and/or the pharyngeal cavity are the target organ for the repellent action of pardaxin.

  8. Effects of water restriction following feeding on nutrient digestibilities, milk yield and composition and blood hormones in lactating Holstein cows under heat stress conditions

    Directory of Open Access Journals (Sweden)

    Jalil Ghassemi Nejad

    2015-08-01

    Full Text Available The effects of water restriction following feeding under heat stress conditions on nutrient digestibilities, milk yield and composition and some blood hormones in lactating Holstein cows were evaluated. The design was completely randomized with 30 high producing lactating Holstein cows (80.8±40.5 DIM which were assigned to two treatment groups (15 cows per treatment. Treatments were free access to water (FAW and 2 h water restriction (2hWR following feeding. Average temperature-humidity index (THI in the farm was over 80 throughout the experiment which defines heat stress conditions. Neutral detergent fibre, organic matter and ether extract digestibilities increased by water restriction (P0.05. Water intake was recorded daily during the digestibility period and was not different between FAW and 2hWR group (P>0.05. Fat corrected milk was higher in 2hWR group than FAW group (P0.05. Somatic cell counts were greater in 2hWR than FAW group (P0.05. Blood prolactin and growth hormone were higher in 2hWR group than the FAW group (P<0.05. It is concluded that water restriction for 2 hours following feeding improved nutrient digestibility of some dietary components and increased milk fat percentage in lactating Holstein cows under heat stress conditions.

  9. Seasonality, Blood Feeding Behavior, and Transmission of Plasmodium Falciparum by Anopheles Arabiensis after an Extended Drought In Southern Zambia

    Science.gov (United States)

    Thuma, Philip E.; Mharakurwa, Sungano; Norris, Douglas E.

    2014-01-01

    Transmission of Plasmodium falciparum is hyperendemic in southern Zambia. However, no data on the entomologic aspects of malaria transmission have been published from Zambia in more than 25 years. We evaluated seasonal malaria transmission by Anopheles arabiensis and An. funestus s.s. and characterized the blood feeding behavior of An. arabiensis in two village areas. Transmission during the 2004–2005 rainy season was nearly zero because of widespread drought. During 2005–2006, the estimated entomologic inoculation rate values were 1.6 and 18.3 infective bites per person per transmission season in each of the two village areas, respectively. Finally, with a human blood index of 0.923, An. arabiensis was substantially more anthropophilic in our study area than comparable samples of indoor-resting An. arabiensis throughout Africa and was the primary vector responsible for transmission of P. falciparum. PMID:17297034

  10. Arthropod repellency, especially tick (Ixodes ricinus), exerted by extract from Artemisia abrotanum and essential oil from flowers of Dianthus caryophyllum.

    Science.gov (United States)

    Tunón, H; Thorsell, W; Mikiver, A; Malander, I

    2006-06-01

    A toluene extract of southernwood (Artemisia abrotanum) and the essential oil from flowers of carnation (Dianthus caryophyllum ) exerted pronounced a repellent effect both against ticks (nymphs of Ixodes ricinus) and yellow fever mosquitoes (Aedes aegypti). The most potent repellents found were coumarin and thujyl alcohol from A. abrotanum and phenylethanol from D. caryophyllum where coumarin and thujyl alcohol were also detected.

  11. Impact of a spatial repellent on malaria incidence in two villages in Sumba, Indonesia.

    Science.gov (United States)

    Syafruddin, Din; Bangs, Michael J; Sidik, Dian; Elyazar, Iqbal; Asih, Puji B S; Chan, Krisin; Nurleila, Siti; Nixon, Christian; Hendarto, Joko; Wahid, Isra; Ishak, Hasanuddin; Bøgh, Claus; Grieco, John P; Achee, Nicole L; Baird, J Kevin

    2014-12-01

    A randomized, double-blinded, placebo-controlled study was conducted to examine the effect of spatial repellent (SR) in households at risk of malaria in Indonesia. Following presumptive radical cure for malaria in 180 adult men representing sentinels of new infection in four clusters within two villages, all households were given either metofluthrin or placebo mosquito coils. Weekly blood smear screening and human-landing mosquito catches were done throughout the 6 months intervention. Malaria infections occurred in 61 subjects living in placebo households and 31 subjects living in SR coil households, suggesting a 52% protective effect of SR. Likewise, anopheles indoor human landing rates were 32% lower in homes receiving SR coils. Differences in the malaria attack rate between SR- and placebo-treated homes was significant when not accounting for the effects of clustering. When the analysis was adjusted for intra-cluster correlation, the differences between SR- and placebo-treated homes were not statistically significant. The findings provide evidence of SR public health benefit and support a larger trial statistically powered to detect those effects. © The American Society of Tropical Medicine and Hygiene.

  12. Repellent activity of DEET against Amblyomma cajennense (Acari: Ixodidae nymphs submitted to different laboratory bioassays Atividade repelente do DEET contra ninfas de Amblyomma cajennense (Acari: Ixodidae em bioensaio laboratorial

    Directory of Open Access Journals (Sweden)

    Sara Fernandes Soares

    2010-03-01

    Full Text Available This study was developed to evaluate the repellent activity of N,N-diethyl-3-methylbenzamide (DEET against Amblyomma cajennense nymphs. Two repellent bioassays were compared and the effective concentration and repellent time were calculated. The fingertip test was accomplished to evaluate in vivo four concentrations of the compound (0.200; 0.100; 0.050 and 0.025 mg.cm-2 and the filter-paper bioassay to evaluate in vitro the two highest concentrations. The compound provided repellence higher than 90% in all concentrations and at least 95% repellency in the highest concentration over 5 hours. The effective concentration against 50% of tested nymphs (EC50 was 0.006 mg.cm-2 and the EC99 was 0.036 mg.cm-2. Those concentrations were lower than the ones obtained against other tick species, denoting the effectiveness of DEET against A. cajennense. The repellency time against 50% of the ticks (RT50 was 4.8 hours and the RT90 was 2.7 hours. Both bioassays were adequate to evaluate A. cajennense repellency and provided similar results; however the in vivo test is more appropriate to estimate the effective concentration and repellency time.Este estudo foi conduzido com o objetivo de avaliar a atividade repelente do N,N-diethyl-3-methylbenzamide (DEET sobre ninfas de Amblyomma cajennense. Dois bioensaios para a avaliação de repelência foram comparados e cálculos da concentração eficaz e do tempo de repelência foram realizados. Foram empregados o bioensaio da ponta do dedo, para avaliação in vivo de quatro concentações do químico (0,200; 0,100; 0,050 e 0,025 mg.cm-2 e o bioensaio do papel filtro, para a avaliação in vitro das duas concentrações mais altas. O composto conferiu mais de 90% de repelência em todas as concentrações utilizadas e 95% de repelência por mais de cinco horas na maior concentração. A concentração do composto efetiva contra 50% das ninfas testadas (CE50 foi de 0,006 mg.cm-2 e a CE99 foi de 0,036 mg.cm-2. Estas

  13. Fumigant and Repellent Activity of Limonene Enantiomers Against Tribolium confusum du Val.

    Science.gov (United States)

    Malacrinò, A; Campolo, O; Laudani, F; Palmeri, V

    2016-10-01

    The use of pesticides, as carried out in the last 50 years, caused several negative environmental and human health consequences, leading to the development of alternative techniques to control pests, such as the use of compounds of plant origin. In this study, we assessed the fumigant and repellent activity of both the enantiomers of limonene, a monoterpene usually found in many plant species, against Tribolium confusum du Val. We tested both molecules at different doses, air temperatures, and in absence and presence of flour. R-(+)-limonene resulted more effective than S-(-)-limonene; indeed, it was able to reach 100% of efficacy at a concentration of 85 mg/L air when tested at different temperatures without flour. Data showed a positive relationship between efficacy and temperature, and a negative effect of the presence of debris on the bioactivity of limonene. Furthermore, repellency trials reported a higher activity of R-(+)-limonene compared to the other enantiomer.

  14. Polymer Surface Textured with Nanowire Bundles to Repel High-Speed Water Drops.

    Science.gov (United States)

    Li, Y P; Li, X Y; Zhu, X P; Lei, M K; Lakhtakia, A

    2018-05-11

    Water drops impacting windshields of high-speed trains and aircraft as well as blades in steam turbine power generators obliquely and at high speeds are difficult to repel. Impacting drops penetrate the void regions of nanotextured and microtextured superhydrophobic coatings, with this pinning resulting in the loss of drop mobility. In order to repel high-speed water drops, we nanotextured polymer surfaces with nanowire bundles separated from their neighbors by microscale void regions, with the nanowires in a bundle separated from their neighbors by nanoscale void regions. Water drops with speeds below a critical speed rebound completely. Water drops with speeds exceeding a critical speed rebound partially, but residual droplets that begin to be pinned undergo a spontaneous dewetting process and slide off. The natural oscillations of residual droplets drive this dewetting process in the interbundle void regions, resulting in a transition from the sticky Wenzel state to the slippery Cassie state without external stimuli.

  15. A survey on the feeding of eventing horses during competition.

    Science.gov (United States)

    Brunner, J; Wichert, B; Burger, D; von Peinen, K; Liesegang, A

    2012-10-01

    This study aims at the comparison of the actual feeding of horses with the recommendations from the literature, and it studies the effects of feeding and exercise on several blood metabolic parameters before and after exercise. Blood samples were collected from 25 horses during one-star eventing competitions and evaluated for blood glucose, insulin, lactate, free fatty acids and triglyceride levels. Questionnaires on the feeding practices of the horses were evaluated. The questionnaires revealed that during training, and on tournament days, horses received on average 4.3 kg of concentrate per day (min. 1.54 kg, max. 8 kg). The statistical analysis showed no significant effect of the amount of concentrate fed before exercise on the measured blood values. Oil was supplied as a supplementary energy source to 30% of the horses, but most of them only received very small quantities (0.02-0.4 l/day). Five horses (20%) had no access to salt supplements at all, and eleven horses (45%) had no access to salt on tournament days. Fifteen horses (60%) were supplied with mineral feed. Twenty-one horses (84%) had daily access to pasture during the training period. During competition, 55% of the horses received roughage ad libitum, compared with 37% during training. The majority of the horses received less roughage on days before the cross-country competition. It could not be ascertained whether feeding a large amounts of roughage had a beneficial effect on performance, because only a few horses in this study were fed with very restrictive roughage. Feeding of most of the horses was in agreement with the recommendations from the literature, except the need for sodium and chloride. The sodium and chloride need for sport horses may be overestimated in literature and needs to be re-evaluated. © 2012 Blackwell Verlag GmbH.

  16. Toxicity and repellency to rats of actidione

    Science.gov (United States)

    Traub, R.; DeWitt, J.B.; Welch, J.F.; Newman, D.

    1950-01-01

    The antibiotic actidione was found to be highly repellent to laboratory rats and to significantly reduce gnawing attacks upon treated paperboards. Rats refused to accept food or water containing this material even under conditions of acute starvation and died of starvation and thirst,rather than accept water containing l.0 mg. of actidione per liter. The compound is highly toxic to .rats with the minimum .lethal dose by oral administration being approximately l.0 mg./Kg body weight. Paperboard treated with the compound resisted gnawing attacks by specially trained and motivated rats for periods of two hundred hours, although similar .untreated boards were pierced within thirty-to sixty minutes.

  17. Prevention of Dengue fever through plant based mosquito repellent Clausena dentata (Willd.) M. Roem (Family: Rutaceae) essential oil against Aedes aegypti l. (Diptera: Culicidae) mosquito.

    Science.gov (United States)

    Rajkumar, S; Jebanesan, A

    2010-03-01

    Plant based repellent against mosquito borne diseases are used recently because synthetic repellents cause side effects like breathing problem, eye irritation, head ache, cough, etc. The use of natural products for dengue control would protect the environment, reduce dependence on expensive synthetic repellents and also generate local employment. Essential oil was isolated by steam distillation which was used against the bites of Aedes aegypti and duration of protection period was assessed. Skin-irritant potential test was also conducted on 25 healthy volunteers by using four-point scale. The increase in the concentrations of essential oil increased the mean protection time against the bites of Aedes aegypti. The lowest mean protection time was 180.0 min for 2.5% and highest time of 255.0 min for 10%. The mean score of zero for skin-irritant potential test for all the concentrations indicated that the essential oil did not cause irritation to human skin. Results indicated that the use of plant based repellent for the control of dengue fever would replace the currently used synthetic repellents which causes many side effects.

  18. Identification of Repellent and Insecticidal Constituents from Artemisia mongolica Essential Oil against Lasioderma serricorne

    Directory of Open Access Journals (Sweden)

    Chunxue You

    2015-01-01

    Full Text Available The aims of this research were to determine the chemical composition and insecticidal and repellent activities of the Artemisia mongolica essential oil against Lasioderma serricorne and to isolate active constituents from the essential oil. The essential oil of A. mongolica was obtained by hydrodistillation and 36 components were identified with GC-MS. Eucalyptol (39.88%, (S-cis-verbenol (14.93%, 4-terpineol (7.20%, (−-camphor (6.02%, and α-terpineol (4.20% were found to be major components. With a further isolation process, five constituents obtained from the essential oil were identified as eucalyptol, verbenol, 4-terpineol, camphor, and α-terpineol. In the progress of assay, it showed that L. serricorne adults had different sensitivities to the crude essential oil and isolated constituents. 4-Terpineol exhibited strongest contact activity against L. serricorne, showing the LD50 value of 8.62 μg/adult. Moreover, camphor and α-terpineol showed stronger fumigant activity (LC50=2.91 and 3.27 mg/L air, resp. against L. serricorne than crude essential oil and other constituents. In addition, the essential oil, eucalyptol, verbenol, and α-terpineol showed comparable repellency against L. serricorne adults. The results indicate that the essential oil and isolated compounds have potential to provide more efficient and safer natural insecticides or repellents for control of insects in food and Chinese medicinal materials preservation.

  19. Inverse estimation of soil hydraulic properties and water repellency following artificially induced drought stress

    Directory of Open Access Journals (Sweden)

    Filipović Vilim

    2018-06-01

    Full Text Available Global climate change is projected to continue and result in prolonged and more intense droughts, which can increase soil water repellency (SWR. To be able to estimate the consequences of SWR on vadose zone hydrology, it is important to determine soil hydraulic properties (SHP. Sequential modeling using HYDRUS (2D/3D was performed on an experimental field site with artificially imposed drought scenarios (moderately M and severely S stressed and a control plot. First, inverse modeling was performed for SHP estimation based on water and ethanol infiltration experimental data, followed by model validation on one selected irrigation event. Finally, hillslope modeling was performed to assess water balance for 2014. Results suggest that prolonged dry periods can increase soil water repellency. Inverse modeling was successfully performed for infiltrating liquids, water and ethanol, with R2 and model efficiency (E values both > 0.9. SHP derived from the ethanol measurements showed large differences in van Genuchten-Mualem (VGM parameters for the M and S plots compared to water infiltration experiments. SWR resulted in large saturated hydraulic conductivity (Ks decrease on the M and S scenarios. After validation of SHP on water content measurements during a selected irrigation event, one year simulations (2014 showed that water repellency increases surface runoff in non-structured soils at hillslopes.

  20. Effect of Feeding Blood Treated with Isometamidium Chloride to Glossina Morsitans Morsitans on the Flies' Subsequent Vectorial Capacity, and Evaluation of an In Vitro Feeding System for the Maintenance of Infected Tsetse Flies

    Energy Technology Data Exchange (ETDEWEB)

    Van den Bossche, P; Van Den Abbeele, J; De Deken, R [Veterinary and Parasitology Departments, Prince Leopold Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp (Belgium)

    2012-07-15

    A repercussion of the release of large numbers of sterile male tsetse flies is the sudden increase in the number of disease vectors. To avoid the potential creation of a trypanosomosis epidemic, studies were conducted aimed at reducing the vectorial capacity of male tsetse flies by offering them a single bloodmeal containing the prophylactic trypanocidal drug isometamidium chloride. Experiments using the pair G. m. morsitans and T. congolense or T. b. brucei showed that a single treatment with isometamidium chloride protected flies from infection with susceptible and resistant trypanosomes for up to 5 days post-treatment. Starvation of isometamidium-treated flies increased their susceptibility to infection with T. congolense. Studies evaluating in vitro feeding of infected flies on citrated bovine blood showed that this feeding regime adversely affected the capacity of trypanosomes to develop in the fly. (author)

  1. Host preferences and feeding patterns of Anopheles sinensis Wiedemann in three sites of Shandong province, China.

    Science.gov (United States)

    Zhang, Chongxing; Shi, Guihong; Cheng, Peng; Liu, Lijuan; Gong, Maoqing

    2017-01-01

    Anopheles sinensis Wiedemann is a major vector of malaria and is among the dominant species in Shandong province of China. Knowledge of the blood-feeding patterns of mosquitoes is crucial for elimination of malaria vectors. However, little information is available on the blood-feeding behaviour of An. sinensis mosquitoes in Shandong province. This study was carried out to compare the blood-feeding behaviour of An. sinensis in malaria-endemic areas of Shandong province China. Adult Anopheles mosquitoes were collected from three malaria-endemic areas (Jimo, Yinan and Shanxian), during the peak months of mosquito population (August and September) from 2014 to 2015. Indoor-resting mosquitoes and outdoor-resting blood-fed females were sampled in the morning hours (0600 to 0900 hrs) from 10 randomly selected houses using pyrethrum spray catch method, and sweeping with an insect net. ELISA was used for the identification of blood meal. The blood meal of each mosquito was tested against antisera specific to human, pig, dog, cow, goat, horse (mule) and fowl. At all indoor study locations of Jimo, Yinan and Shanxian, 59.4, 68.1 and 98.8% blood-engorged female An. sinensis collected from cattle sheds fed almost exclusively on bovines, respectively. For outdoor locations, at Jimo site, 27.27 and 49.55% An. sinensis fed on cattle and pigs; at Yinan, 30.42% fed on cattle and 36.88% fed both on cattle and goats, while no pig antibodies were detected. At Shanxian, percent of An. sinensis that fed on cattle, pigs and cattle-goat was 20.72, 27.62 and 21.78%, respectively. The analysis of An. sinensis blood meals in all the three studied areas from human houses, cattle sheds, pig sheds and mixed dwellings revealed that An. sinensis prefers cattle hosts, and can feed on other available animal hosts if the cattle hosts are absent, and the mosquitoes readily feed on humans when domestic animals (cattle and pigs) are not nearby for feeding. The analysis of blood meal revealed that An

  2. Post-fire interactions between soil water repellency, soil fertility and plant growth in soil collected from a burned piñon-juniper woodland

    Science.gov (United States)

    Fernelius, Kaitlynn J.; Madsen, Matthew D.; Hopkins, Bryan G.; Bansal, Sheel; Anderson, Val J.; Eggett, Dennis L.; Roundy, Bruce A.

    2017-01-01

    Woody plant encroachment can increase nutrient resources in the plant-mound zone. After a fire, this zone is often found to be water repellent. This study aimed to understand the effects of post-fire water repellency on soil water and inorganic nitrogen and their effects on plant growth of the introduced annual Bromus tectorum and native bunchgrass Pseudoroegneria spicata. Plots centered on burned Juniperus osteosperma trees were either left untreated or treated with surfactant to ameliorate water repellency. After two years, we excavated soil from the untreated and treated plots and placed it in zerotension lysimeter pots. In the greenhouse, half of the pots received an additional surfactant treatment. Pots were seeded separately with B. tectorum or P. spicata. Untreated soils had high runoff, decreased soilwater content, and elevated NO3eN in comparison to surfactant treated soils. The two plant species typically responded similar to the treatments. Above-ground biomass and microbial activity (estimated through soil CO2 gas emissions) was 16.8-fold and 9.5-fold higher in the surfactant-treated soils than repellent soils, respectably. This study demonstrates that water repellency can influence site recovery by decreasing soil water content, promoting inorganic N retention, and impairing plant growth and microbial activity.

  3. Acaricidal activity and repellency of essential oil from Piper aduncum and its components against Tetranychus urticae.

    Science.gov (United States)

    Araújo, Mário J C; Câmara, Cláudio A G; Born, Flávia S; Moraes, Marcílio M; Badji, César A

    2012-06-01

    The chemical composition of essential oil of leaves of Piper aduncum L., growing wild in a fragment of the Atlantic Rainforest biome in northeastern Brazil, was determined through gas chromatography-mass spectrometry. The acaricidal activity and repellency of the essential oil and its components [dillapiole (0.28 g/ml), α-humulene (0.016 g/ml), (E)-nerolidol (0.0007 g/ml) and β-caryophyllene (0.0021 g/ml)] were evaluated in the laboratory against adults of Tetranychus urticae Koch. The mites were more susceptible to the oil in fumigation tests (LC(50) = 0.01 μl/l of air) than in contact test with closed Petri dish (LC(50) = 7.17 μl/ml); mortality was reduced by approximately 50 % in the latter test. The repellent action of the oil and toxicity by fumigation and contact did not differ significantly from the positive control (eugenol). The repellent activity was attributed to the components (E)-nerolidol, α-humulene and β-caryophyllene, whereas toxicity by fumigation and contact was attributed to β-caryophyllene. The effect of Piper oil and the role of its components regarding host plant preference with a two-choice leaf disk test are also discussed.

  4. Repellent and insecticidal efficacy of a combination of dinotefuran, pyriproxyfen and permethrin (Vectra® 3D against Culex pipiens in dogs

    Directory of Open Access Journals (Sweden)

    Emilie Bouhsira

    2016-09-01

    Compared to control dogs, the spot-on formulation provided a repellent efficacy (anti-feeding effect against mosquitoes of 98.9%, 98.8%, 98.6%, 96.7% and 97.9% on Days 1, 7, 14, 21 and 28 respectively. There was a significant difference (p ≤ 0.05 between the treated and controlled groups on every assessment day. The insecticidal efficacy on treated dogs at 90 min was 34.7%, 50.3%, 39.7%, 22.8% and 11.4% on Days 1, 7, 14, 21 and 28 respectively. There was a significant difference between the treated and controlled groups for live mosquitoes for all assessment days (p 96% against Culex pipiens which lasted for 28 days. The results suggest that the Vectra® 3D spot-on solution could be used as an effective mosquito control strategy in dogs and is therefore recommended for use in a dirofilariosis prevention programme.

  5. Dihydronepetalactones deter feeding activity by mosquitoes, stable flies, and deer ticks.

    Science.gov (United States)

    Feaster, John E; Scialdone, Mark A; Todd, Robin G; Gonzalez, Yamaira I; Foster, Joseph P; Hallahan, David L

    2009-07-01

    The essential oil of catmint, Nepeta cataria L., contains nepetalactones, that, on hydrogenation, yield the corresponding dihydronepetalactone (DHN) diastereomers. The DHN diastereomer (4R,4aR,7S,7aS)-4,7-dimethylhexahydrocyclopenta[c]pyran-1(3H)-one, DHN 1) was evaluated as mosquito repellent, as was the mixture of diastereomers {mostly (4S,4aR,7S,7aR)-4,7-dimethylhexahydrocyclopenta[c]pyran-1(3H)-one, DHN 2} present after hydrogenation of catmint oil itself. The repellency of these materials to Aedes aegypti L. and Anopheles albimanus Wiedemann mosquitoes was tested in vitro and found to be comparable to that obtained with the well-known insect repellent active ingredient N,N-diethyl-3-methylbenzamide (DEET). DHN 1 and DHN 2 also repelled the stable fly, Stomoxys calcitrans L., in this study. DHN 1, DHN 2, and p-menthane-3,8-diol (PMD), another natural monoterpenoid repellent, gave comparable levels of repellency against An. albimanus and S. calcitrans. Laboratory testing of DHN 1 and DHN 2 using human subjects with An. albimanus mosquitoes was carried out. Both DHN 1 and DHN 2 at 10% (wt:vol) conferred complete protection from bites for significant periods of time (3.5 and 5 h, respectively), with DHN2 conferring protection statistically equivalent to DEET. The DHN 1 and DHN 2 diastereomers were also efficaceous against black-legged tick (Ixodes scapularis Say) nymphs.

  6. Efficacy of Plant-Derived and Synthetic Compounds on Clothing as Repellents Against Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae)

    Science.gov (United States)

    2012-01-01

    efÞcacy of the repellent deet against Aedes aegypti . J. Am. Mosq. Control Assoc. 14: 178Ð182. Robbins, P. J., and M. G. Cherniack. 1986. Review of...number of reported Lyme disease cases reached an all- time high of35,000 in 2008 (CDC 2010). The blacklegged tick, Ixodes scapularis Say, the principal...Paddock 2003, Mixson et al. 2006, Apperson et al. 2008). Repellents remain the primary method of personal protection against tick bites (Piesman and

  7. Repellant and insecticidal activities of shyobunone and isoshyobunone derived from the essential oil of Acorus calamus rhizomes.

    Science.gov (United States)

    Chen, Hai-Ping; Yang, Kai; Zheng, Li-Shi; You, Chun-Xue; Cai, Qian; Wang, Cheng-Fang

    2015-01-01

    It was found that the essential oil of Acorus calamus rhizomes showed insecticidal activity. The aim of this study was to determine the chemical composition of the essential oil from A. calamus rhizomes, evaluate insecticidal and repellant activity against Lasioderma serricorne (LS) and Tribolium castaneum (TC), and to isolate any insecticidal constituents from the essential oil. Essential oil from A. calamus was obtained by hydrodistillation and analyzed by gas chromatography (GC) flame ionization detector and GC-mass spectrometry. The insecticidal and repellant activity of the essential oil and isolated compounds was tested using a variety of methods. The main components of the essential oil were identified to be isoshyobunone (15.56%), β-asarone (10.03%), bicyclo[6.1.0]non-1-ene (9.67%), shyobunone (9.60%) and methylisoeugenol (6.69%). Among them, the two active constituents were isolated and identified as shyobunone and isoshyobunone. The essential oil showed contact toxicity against LS and TC with LD50 values of 14.40 and 32.55 μg/adult, respectively. The isolated compounds, shyobunone and isoshyobunone also exhibited strong contact toxicity against LS adults with LD50 values of 20.24 and 24.19 μg/adult, respectively, while the LD50 value of isoshyobunone was 61.90 μg/adult for TC adults. The essential oil, shyobunone and isoshyobunone were strongly repellent (98%, 90% and 94%, respectively, at 78.63 nL/cm(2), after 2 h treatment) against TC. The essential oil, shyobunone and isoshyobunone possessed insecticidal and repellant activity against LS and TC.

  8. Hydrophobic duck feathers and their simulation on textile substrates for water repellent treatment

    International Nuclear Information System (INIS)

    Liu Yuyang; Chen Xianqiong; Xin, J H

    2008-01-01

    Inspired by the non-wetting phenomena of duck feathers, the water repellent property of duck feathers was studied at the nanoscale. The microstructures of the duck feather were investigated by a scanning electron microscope (SEM) imaging method through a step-by-step magnifying procedure. The SEM results show that duck feathers have a multi-scale structure and that this multi-scale structure as well as the preening oil are responsible for their super hydrophobic behavior. The microstructures of the duck feather were simulated on textile substrates using the biopolymer chitosan as building blocks through a novel surface solution precipitation (SSP) method, and then the textile substrates were further modified with a silicone compound to achieve low surface energy. The resultant textiles exhibit super water repellent properties, thus providing a simple bionic way to create super hydrophobic surfaces on soft substrates using flexible material as building blocks

  9. Self-Trapping Self-Repelling Random Walks

    Science.gov (United States)

    Grassberger, Peter

    2017-10-01

    Although the title seems self-contradictory, it does not contain a misprint. The model we study is a seemingly minor modification of the "true self-avoiding walk" model of Amit, Parisi, and Peliti in two dimensions. The walks in it are self-repelling up to a characteristic time T* (which depends on various parameters), but spontaneously (i.e., without changing any control parameter) become self-trapping after that. For free walks, T* is astronomically large, but on finite lattices the transition is easily observable. In the self-trapped regime, walks are subdiffusive and intermittent, spending longer and longer times in small areas until they escape and move rapidly to a new area. In spite of this, these walks are extremely efficient in covering finite lattices, as measured by average cover times.

  10. ThermaCELL and OFF! Clip-On Devices Tested for Repellency and Mortality Against Amblyomma americanum (Acari: Ixodida: Amblyommidae).

    Science.gov (United States)

    Bibbs, Christopher S; Xue, Rui-De

    2016-07-01

    The ThermaCELL with allethrin and OFF! Clip-on with metofluthrin were tested in a 939 m 2 vented enclosure against nymphal lone star ticks, Amblyomma americanum (L.). Repellency assays were conducted at varying distances relative to product specifications for repellency range. Nymphal ticks acclimated for 24 h in chambers attached to 10 repellency tracks per repetition. Devices were turned on, and the tick travel distance and delay until beginning to travel were recorded. Mortality of ticks was recorded after 24 h. Mortality assays were also conducted at the same distances with five ticks per cage, and 12 cages per distance radially distributed around a device. Cages were removed after 5 min, 15 min, 30 min, and 60 min of exposure and checked after 24 h for mortality. Significant travel distance was found when exposed to the ThermaCELL and OFF! Clip-on at their shortest test distances. Significant mortality also resulted at the same distances. Ticks exposed to active devices for longer than 15 min had significant mortality at the shortest distance for OFF! Clip-on and multiple distances for the ThermaCELL. Overall, the spatial repellent devices ThermaCELL with allethrin and OFF! Clip-on with metofluthrin both demonstrated desirable effects when tested against A. americanum nymphs. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Insecticidal and Repellant Activities of Four indigenous medicinal Plants Against Stored Grain Pest, Tribolium castaneum (Herbst (Coleoptera:Tenebrionidae

    Directory of Open Access Journals (Sweden)

    S.R.Pugazhvendan

    2012-05-01

    Full Text Available Objective: The present investigation was aimed to assess the impact of four indigenous plants for their insecticidal and repellent activity against Tribolium castaneum (Herbst, a stored grain pest and they were tested in the laboratory. Methods: Four widely distributed plants (Artemisia vulgaris, Sphaeranthus indicus, Tephrosia purpurea, and Prosopis juliflora were sequentially extracted with increasing polarity of organic solvents such as, hexane, chloroform and ethyl acetate were evaluated for their insecticidal and repellent activities against Tribolium castaneum by adapting the standard protocol in in vitro. Results: Data pertaining to the present investigation clearly revealed that the percentage of mortality was maximum in(72 hr 58% hexane extract of A. vulgaris, chloroform extract (72 hr 34% of S. indicus, and ethyl acetate extract (72 hr 52% of T. purpurea. Repellant activities of plant extracts were tested against T. castaneum, repellent activity was maximum in hexane extract of P. fuliflora, ( EPI value for P. fuliflora in 2.5% was – 0.11 and – 0.33 at 1hr and 6 hr respectively chloroform extract of T. purpurea (2.5% was -0.17 at 6 hr and ethyl acetate extract of S. indicus (2.5% was -0.65 at 6 hr against T. castaneum. Conclusions: The present work for botanical products to control the insect pest of stored grain Tribolium castaneum (Herbst.These results suggest the presence of actives toxic substances acting after consumption or topical application.

  12. BIOCHEMICAL STATUS OF BLOOD SERUM OF RAINBOW TROUT Oncorhynchus mykiss (Walbaum, 1792 UNDER DIFFERENT KEEPING AND FEEDING CONDITIONS

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    Edhem Hasković

    2013-01-01

    Full Text Available We analyzed the blood serum of the rainbow trout in relation to various physico-chemical properties of water and diet composition. Fish were reared in two ponds that were supplied by water from different sources. The identified differences in the biochemical parameters are caused by different environmental factors in ponds and different feed composition. Low oxygen values caused by different temperatures is a key stress factor of the noted differences. Statistically significant differences are noted for AST (aspartate aminotransferase, ALT (alanine aminotransferase, triglycerides, urea and iron (0.00. Evident were also different mineral concentrations of Ca and P (0.05 as well as glucose and cholesterol (0.05.

  13. Plasma Vitamin E and Blood Selenium Concentrations in Norwegian Dairy Cows: Regional Differences and Relations to Feeding and Health

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    Østerås O

    2005-12-01

    Full Text Available Plasma α-tocopherol (vit E and blood selenium (Se concentrations in February were determined in samples from 314 dairy cows in Norway, selected to provide a representative subset of the Norwegian dairy cow population. Each sample was followed by a questionnaire with information about feeding of the cow at the time of sampling. The results were correlated to herd data and to calving and health data for each cow from the Norwegian Dairy Herd Recording System and the Norwegian Cattle Health Recording System. The mean concentrations were 6.9 μg vit E per ml plasma and 0.16 μg Se per g blood. Both levels were highest in mid lactation. Plasma vit E varied with the amount of silage fed to the cow, while blood Se varied with the amount of concentrates and mineral supplements, and with geographical region. No differences in vit E or Se levels were found between cows with recorded treatments for mastitis, parturient paresis or reproductive disorders in the lactation during or immediately prior to sampling, and those without such treatments. For ketosis, a small difference in blood Se was found between the groups with or without recorded treatments. It is concluded that winter-fed lactating cows in Norway had an adequate plasma level of vit E and a marginal-to-adequate level of Se.

  14. Plasma Vitamin E and Blood Selenium Concentrations in Norwegian Dairy Cows: Regional Differences and Relations to Feeding and Health

    Directory of Open Access Journals (Sweden)

    Sivertsen T

    2006-12-01

    Full Text Available Plasma α-tocopherol (vit E and blood selenium (Se concentrations in February were determined in samples from 314 dairy cows in Norway, selected to provide a representative subset of the Norwegian dairy cow population. Each sample was followed by a questionnaire with information about feeding of the cow at the time of sampling. The results were correlated to herd data and to calving and health data for each cow from the Norwegian Dairy Herd Recording System and the Norwegian Cattle Health Recording System. The mean concentrations were 6.9 μg vit E per ml plasma and 0.16 μg Se per g blood. Both levels were highest in mid lactation. Plasma vit E varied with the amount of silage fed to the cow, while blood Se varied with the amount of concentrates and mineral supplements, and with geographical region. No differences in vit E or Se levels were found between cows with recorded treatments for mastitis, parturient paresis or reproductive disorders in the lactation during or immediately prior to sampling, and those without such treatments. For ketosis, a small difference in blood Se was found between the groups with or without recorded treatments. It is concluded that winter-fed lactating cows in Norway had an adequate plasma level of vit E and a marginal-to-adequate level of Se.

  15. Effect of levels of urea and cassava chip on feed intake, rumen fermentation, blood metabolites and microbial populations in growing goats

    Directory of Open Access Journals (Sweden)

    Metha Wanapat

    2007-01-01

    Full Text Available The study was conducted to assess effect of levels of urea and cassava chip (CC on feed intake, rumen ecology, blood metabolites and microbial populations. Four, Thai Native X Anglo Nubian crossbred growing male goats with an average liveweight 19.0+1 kg were randomly assigned according to a 4x4 Latin square design to receive one of four diets: T1=urea at 0 % (CC=30%, T2=urea at 1% (CC=40%, T3=urea at 2% (CC = 50% and T4=urea at 3%(CC=60%, of DM basis, respectively. Elephant grass (Pennisetum purpureum was offered on an ad lib basis. The results revealed that total DM intake (%BW and g/kg W0.75 and BW change were similar among treatments (p>0.05. Likewise, rumen pH, BUN, blood glucose, PCV and microbial populations were similar among treatments (p>0.05, while NH3-N increased as the urea level increased and were found highest (p<0.05 in T4 at 12.8 mg/dL. Based on this experiment, it can be concluded that a higher level of urea (3% could be used with a high level of CC in concentrate and it was good approach in exploiting the use of local feed resources for goat production.

  16. Water repellency of clay, sand and organic soils in Finland

    Directory of Open Access Journals (Sweden)

    K. RASA

    2008-12-01

    Full Text Available Water repellency (WR delays soil wetting process, increases preferential flow and may give rise to surface runoff and consequent erosion. WR is commonly recognized in the soils of warm and temperate climates. To explore the occurrence of WR in soils in Finland, soil R index was studied on 12 sites of different soil types. The effects of soil management practice, vegetation age, soil moisture and drying temperature on WR were studied by a mini-infiltrometer with samples from depths of 0-5 and 5-10 cm. All studied sites exhibited WR (R index >1.95 at the time of sampling. WR increased as follows: sand (R = 1.8-5.0 < clay (R = 2.4-10.3 < organic (R = 7.9-undefined. At clay and sand, WR was generally higher at the soil surface and at the older sites (14 yr., where organic matter is accumulated. Below 41 vol. % water content these mineral soils were water repellent whereas organic soil exhibited WR even at saturation. These results show that soil WR also reduces water infiltration at the prevalent field moisture regime in the soils of boreal climate. The ageing of vegetation increases WR and on the other hand, cultivation reduces or hinders the development of WR.;

  17. A Simple Beta-Function Model for Soil-Water Repellency as a Function of Water and Organic Carbon Contents

    DEFF Research Database (Denmark)

    Karunarathna, Anurudda Kumara; Kawamoto, Ken; Møldrup, Per

    2010-01-01

    Soil-water content (θ) and soil organic carbon (SOC) are key factors controlling the occurrence and magnitude of soil-water repellency (WR). Although expressions have recently been proposed to describe the nonlinear variation of WR with θ, the inclusion of easily measurable parameters in predictive...... conditions for 19 soils were used to test the model. The beta function successfully reproduced all the measured soil-water repellency characteristic, α(θ), curves. Significant correlations were found between model parameters and SOC content (1%-14%). The model was independently tested against data...

  18. Effect of kaolinite and Ca-montmorillonite on the alleviation of soil water repellency

    Czech Academy of Sciences Publication Activity Database

    Dlapa, P.; Doerr, S. H.; Lichner, Ľ.; Šír, Miloslav; Tesař, Miroslav

    2004-01-01

    Roč. 50, č. 8 (2004), s. 358-363 ISSN 0370-663X R&D Projects: GA AV ČR IAA3042301; GA AV ČR IBS2060104 Keywords : water repellency * kaolinite * Ca-montmorillonite Subject RIV: DA - Hydrology ; Limnology Impact factor: 0.379, year: 2004

  19. Lantana montevidensis Essential Oil: Chemical Composition and Mosquito Repellent Activity against Aedes aegypti

    Science.gov (United States)

    The essential oil (EO) of Lantana montevidensis (Spreng.) Briq. (L. sellowiana Link & Otto) was investigated for its chemical composition and mosquito repellent activity. The essential oil obtained by hydrodistillation of aerial plant parts was analyzed by GC-FID and GC-MS. The major constituents we...

  20. POSSIBILITIES TO USE NATURAL EXTRACTS FROM MEDICINAL AND AROMATIC PLANTS (MAP LIKE BOTANICAL REPELLENT OR INSECTICIDE COMPOUNDS AGAINST PEST INSECTS IN ECOLOGICAL CROPS (II

    Directory of Open Access Journals (Sweden)

    Irina IONESCU-MĂLĂNCUŞ

    2013-12-01

    Full Text Available Botanical insecticides have long been touted as attractive alternatives to synthetic chemical insecticides for pest management because botanicals reputedly pose little threat to the environment or to human health. The body of scientific literature documenting bioactivity of plant derivatives to arthropods pests continues to expand i.e. repellents based on essential oils extracted from Chenopodium ambrosioides, Eucalyptus saligna, Rosmarinus officinalis to mosquitoes, or cinnamon oil, sandalwood oil and turmeric oil are previously reported as insect repellents evaluatede in the laboratory conditions. With the constantly increasing problems of insecticide resistance and increasing public concerns regarding pesticide safety, new, safer active ingredients are becoming necessary to replace existing compounds on the market. The present study carried out in the period 2010-2012 comprises a review of two insect repellents, followed by some new research conducted in our laboratory on plant-derived insect repellents. The two alkaloids tested against the Colorado potato beetle, Leptinotarsa decemlineata Say in laboratory conditions was obtained by water and alchohol extraction from two vegetal species, Cichorium intybus L. (Asterales:Asteraceae and Delphinium consolida L. (Ranales:Ranunculaceae. The tests carried out in laboratory and field experimentally plots under cages permit to evaluate several other compounds for repellent activity of lacctucin alkaloids.

  1. Insecticidal, acaricidal and repellent effects of DEET- and IR3535-impregnated bed nets using a novel long-lasting polymer-coating technique.

    Science.gov (United States)

    Faulde, Michael K; Albiez, Gunther; Nehring, Oliver

    2010-03-01

    A novel long-lasting repellent-treated net (LLRTN) has been designed by binding the skin repellents N,N-diethyl-m-toluamide (DEET), or IR3535, onto the fibres of bed net fabric using a new polymer-coating technique. The repellent toxicological effectiveness and residual activity of a factory-based repellent-impregnated fabric has been evaluated by laboratory testing against adult Aedes aegypti mosquitoes and nymphal Ixodes ricinus ticks. By using this repellent-embedding impregnation technique, concentrations exceeding 10 g/m(2) could be achieved with one single polymer layer. Both DEET- and IR3535-impregnated fabrics revealed a dose-dependent insecticidal as well as acaricidal activity. One hundred percent knockdown times of DEET-treated bed nets ranged from 187.5 +/- 31.8 to 27.5 +/- 3.5 min against A. aegypti, and between 214 +/- 47 and 22.6 +/- 5 min against nymphal I. ricinus, linked to a DEET concentration of 1.08 and 10.58 g/m(2), respectively. With IR3535, A. aegypti produced dose-dependent 100% knockdown times varying from 87.5 +/- 10.6 to 57.5 +/- 3.5 min and between 131.4 +/- 6.5 and 33.8 +/- 5 min against nymphal I. ricinus, respectively, linked to concentrations between 1.59 and 10.02 g/m(2). One hundred percent repellency measured by complete landing and biting protection of impregnated fabric by using the arm-in-cage test could be achieved at DEET concentrations exceeding 3.7 to 3.9 g/m(2), and for IR3535 concentrations over 10 g/m(2). One hundred percent landing and biting protection could be preserved with DEET-treated fabrics for 29 weeks at an initial concentration of 4.66 g/m(2), 54 weeks at 8.8 g/m(2), 58 weeks at 9.96 g/m(2) and 61 weeks at 10.48 g/m(2) for DEET, and 23 weeks for IR3535-treated fabric at a concentration of 10.02 g/m(2). Unlike repellent-treated fabric, a brand of a commercially available long-lasting insecticide-treated net tested containing 500 mg permethrin/m(2) did not protect from mosquito bites. First results on

  2. Repellence and toxicity of plant essential oils to the potato aphid, Macrosiphum euphorbiae

    NARCIS (Netherlands)

    Munneke, M.E.; Bruin, de A.; Moskal, J.R.; Tol, van R.W.H.M.

    2004-01-01

    Several plant essential oils were tested for their effect on behaviour and mortality of M. euphorbiae. Olfactory and contact experiments were performed to study these effects. We found that host plant and formulation of the different oils have a strong influence on repellence and mortality of the

  3. Comparison of time-restricted and ad libitum self-feeding on the growth, feeding behavior and daily digestive enzyme profiles of Atlantic salmon

    Science.gov (United States)

    Shi, Ce; Liu, Ying; Yi, Mengmeng; Zheng, Jimeng; Tian, Huiqin; Du, Yishuai; Li, Xian; Sun, Guoxiang

    2017-07-01

    Although it has been hypothesized that a predictable feeding regime in animals allows physiological variables to be adjusted to maximize nutrient utilization and, hence, better growth performance, the assumption has rarely been tested. This study compares the effects of time-restricted versus free access self-feeding on the growth, feeding behavior and daily digestive enzyme rhythms of Atlantic salmon ( Salmo salar). In an experiment that lasted 6 weeks, fish (109.9 g) were divided into two groups: group 1 had free access to a self-feeder (FA); group 2 received three meals per day (2 h per meal) at dawn, midday and dusk via a time-restricted self-feeder (TR). At the end of the experiment, the fish were sampled every 3 h over a 24-h period. The results showed that the TR fish quickly synchronized their feeding behavior to the feeding window and their blood glucose showed a significant postprandial increase, while FA fish displayed no statistically significant rhythms ( P>0.05). Pepsin activity of TR fish also showed a significant daily rhythm ( P0.05). In conclusion, the study failed to confirm a link between the entrainment of daily digestive enzyme profiles and growth performance, with the TR group showing comparatively poor blood glucose regulation.

  4. First molecular identification of the vertebrate hosts of Culicoides imicola in Europe and a review of its blood-feeding patterns worldwide: implications for the transmission of bluetongue disease and African horse sickness.

    Science.gov (United States)

    Martínez-DE LA Puente, J; Navarro, J; Ferraguti, M; Soriguer, R; Figuerola, J

    2017-12-01

    Culicoides (Diptera: Ceratopogonidae) are vectors of pathogens that affect wildlife, livestock and, occasionally, humans. Culicoides imicola (Kieffer, 1913) is considered to be the main vector of the pathogens that cause bluetongue disease (BT) and African horse sickness (AHS) in southern Europe. The study of blood-feeding patterns in Culicoides is an essential step towards understanding the epidemiology of these pathogens. Molecular tools that increase the accuracy and sensitivity of traditional methods have been developed to identify the hosts of potential insect vectors. However, to the present group's knowledge, molecular studies that identify the hosts of C. imicola in Europe are lacking. The present study genetically characterizes the barcoding region of C. imicola trapped on farms in southern Spain and identifies its vertebrate hosts in the area. The report also reviews available information on the blood-feeding patterns of C. imicola worldwide. Culicoides imicola from Spain feed on blood of six mammals that include species known to be hosts of the BT and AHS viruses. This study provides evidence of the importance of livestock as sources of bloodmeals for C. imicola and the relevance of this species in the transmission of BT and AHS viruses in Europe. © 2017 The Royal Entomological Society.

  5. Chemosensory responses to the repellent nepeta essential oil and its major component nepetalactone by the yellow fever mosquito, aedes aegypti, a vector of zika virus

    Science.gov (United States)

    Nepeta essential oil (Neo) (catnip) and its major component, nepetalactone, have long been known to repel insects including mosquitoes. However, the neural mechanisms through which these repellents are detected by mosquitoes, including the yellow fever mosquito Aedes aegypti, an important vector of...

  6. LD50 and repellent effects of essential oils from Argentinian wild plant species on Varroa destructor.

    Science.gov (United States)

    Ruffinengo, Sergio; Eguaras, Martin; Floris, Ignazio; Faverin, Claudia; Bailac, Pedro; Ponzi, Marta

    2005-06-01

    The repellent and acaricidal effects of some essential oils from the most typical wild plant species of northern Patagonia, Argentina, on Varroa destructor Anderson & Trueman were evaluated using a complete exposure test. Honey bees, Apis mellifera L., and mites (five specimens of each per dish) were introduced in petri dishes having different oil concentrations (from 0.1 to 25 micro per cage). Survival of bees and mites was registered after 24, 48, and 72 h. An attraction/repellence test was performed using a wax tube impregnated with essential oil and another tube containing wax only. The lowest LD50 values for mites were registered for Acantholippia seriphioides (A. Gray) Mold. (1.27 microl per cage) and Schinus molle L. (2.65 microl per cage) after 24 h, and for Wedelia glauca (Ortega) O. Hoffm. ex Hicken (0.59 microl per cage) and A. seriphioides (1.09 microl per cage) after 72 h of treatment. The oil with the highest selectivity ratio (A. mellifera LD50/V. destructor LD50) was the one extracted from S. molle (>16). Oils of Lippia junelliana (Mold.) Troncoso, Minthostachys mollis (HBK) Grieseb., and Lippia turbinata Grieseb. mixed with wax had repellent properties. None of the oils tested had attractive effects on Varroa mites.

  7. Hypoxia modifies the feeding preferences of Drosophila. Consequences for diet dependent hypoxic survival

    Directory of Open Access Journals (Sweden)

    Frelin Christian

    2010-05-01

    Full Text Available Abstract Background Recent attention has been given to the relationships between diet, longevity, aging and resistance to various forms of stress. Flies do not simply ingest calories. They sense different concentrations of carbohydrate and protein macronutrients and they modify their feeding behavior in response to changes in dietary conditions. Chronic hypoxia is a major consequence of cardiovascular diseases. Dietary proteins have recently been shown to decrease the survival of chronically hypoxic Drosophila. Whether flies modify their feeding behavior in response to hypoxia is not currently known. This study uses the recently developed capillary feeding assay to analyze the feeding behavior of normoxic and chronically hypoxic Drosophila melanogaster. Results The intakes rates of sucrose and yeast by normoxic or chronically hypoxic flies (5% O2 were analyzed under self selecting and "no choice" conditions. Chronically hypoxic flies fed on pure yeast diets or mixed diets under self selection conditions stopped feeding on yeast. Flies fed on mixed diets under "no choice" conditions reduced their food intakes. Hypoxia did not modify the adaptation of flies to diluted diets or to imbalanced diets. Mortality was assessed in parallel experiments. Dietary yeast had two distinct effects on hypoxic flies (i a repellent action which eventually led to starvation and which was best observed in the absence of dietary sucrose and (ii a toxic action which led to premature death. Finally we determined that hypoxic survivals were correlated to the intakes of sucrose, which suggested that dietary yeast killed flies by reducing their intake of sucrose. The feeding preferences of adult Drosophila were insensitive to NO scavengers, NO donor molecules and inhibitors of phosphodiesterases which are active on Drosophila larvae. Conclusion Chronically hypoxic flies modify their feeding behavior. They avoid dietary yeast which appears to be toxic. Hypoxic survival is

  8. Identification of Repellent and Insecticidal Constituents of the Essential Oil of Artemisia rupestris L. Aerial Parts against Liposcelis bostrychophila Badonnel

    OpenAIRE

    Liu, Xin; Li, Yin; Li, He; Deng, Zhi; Zhou, Ligang; Liu, Zhi; Du, Shu

    2013-01-01

    The aim of this research was to determine the chemical composition and insecticidal and repellent activity of the essential oil of Artemisia rupestris L. aerial parts against the booklice Liposcelis bostrychophila Badonnel and isolation of insecticidal and repellent constituents from the essential oil. The essential oil of A. rupestris was obtained by hydrodistillation and analyzed by GC-MS. A total of 30 components of the essential oil of A. rupestris was identified and the principal compoun...

  9. Identification of Repellent and Insecticidal Constituents of the Essential Oil of Artemisia rupestris L. Aerial Parts against Liposcelis bostrychophila Badonnel

    Directory of Open Access Journals (Sweden)

    Zhi Long Liu

    2013-09-01

    Full Text Available The aim of this research was to determine the chemical composition and insecticidal and repellent activity of the essential oil of Artemisia rupestris L. aerial parts against the booklice Liposcelis bostrychophila Badonnel and isolation of insecticidal and repellent constituents from the essential oil. The essential oil of A. rupestris was obtained by hydrodistillation and analyzed by GC-MS. A total of 30 components of the essential oil of A. rupestris was identified and the principal compounds in the essential oil were α-terpinyl acetate (37.18%, spathulenol (10.65%, α-terpineol (10.09%, and linalool (7.56%, followed by 4-terpineol (3.92% and patchoulol (3.05%. Based on bioactivity-guided fractionation, the four active constituents were isolated from the essential oil and identified as α-terpineol, α-terpinyl acetate, 4-terpineol and linalool. The essential oil of A. rupestris exhibited contact toxicity against L. bostrychophila with LD50 value of 414.48 µg/cm2. α-Terpinyl acetate (LD50 = 92.59 µg/cm2 exhibited stronger contact toxicity against booklice than α-terpineol (LD50 = 140.30 µg/cm2, 4-terpineol (LD50 = 211.35 µg/cm2, and linalool (LD50 = 393.16 µg/cm2. The essential oil of A. rupestris (LC50 = 6.67 mg/L air also possessed fumigant toxicity against L. bostrychophila while the four constituents, 4-terpineol, α-terpineol, α-terpinyl acetate and linalool had LC50 values of 0.34, 1.12, 1.26 and 1.96 mg/L air, respectively. α-Terpinol and α-terpinyl acetate showed strong repellency against L. bostrychophila, while linalool and 4-terpinol exhibited weak repellency. The results indicate that the essential oil of A. rupestris aerial parts and its constituent compounds have potential for development into natural insecticides or fumigants as well as repellents for control of insects in stored grains.

  10. Phenological stage effect on phenolic composition and repellent potential of Mentha pulegium against Tribolium castaneum and Lasioderma serricorne

    Directory of Open Access Journals (Sweden)

    Nidhal Salem

    2018-01-01

    Full Text Available Objective: To elucidate for the first time the phenological stage effect on polyphenol, flavonoid and proanthocyanidin contents of pennyroyal (Mentha pulegium as well as their antioxidant capacities and insecticidal potentials against Tribolium castaneum and Lasioderma serricorne. Methods: Crude methanol extracts from pennyroyal (Mentha pulegium aerial parts were evaluated for their antiradical, reducing power activities and repellent potentials against selected coleopteran insects during different phenological stages. Results: Phenolic contents of pennyroyal aerial parts and their antioxidant effects were significantly dependent on maturity stage of the plant. The maximum of phenol production was reached during the full flowering stage. Apigenin was the major phenol in Mentha pulegium with an amount of 6.01 mg/g of dry vegetable matter during this period. Nevertheless, at fructification stage, the highest antioxidant activity was not related to high phenolic content. The repulsive effect of pennyroyal extract showed that Lasioderma serricorne was more susceptible to pennyroyal extract than Tribolium castaneum with corresponding median repellent dose values of 0.124 and 0.006 mg/mL respectively. Moreover, great differences in insect repulsion depending on extract concentrations, exposure time and developmental stage was observed. For the lowest concentration (0.125 mg/mL, the repellent effect against Tribolium reached its maximum (90% during the fructification stage (after 24 h of exposure while this repellent effect was 80% during the vegetative stage. Conclusions: Due to the strong insecticidal potential of pennyroyal extracts, this study highlights the therapeutic properties of this plant and encourages its use as a safer, environmental-friendly and efficient insecticide in food industry.

  11. Dry-season soil water repellency affects Tahoe Basin infiltration rates

    OpenAIRE

    Rice, Erin C; Grismer, Mark E

    2010-01-01

    Lake Tahoe’s declining clarity makes the identification of runoff and erosion sources and evaluation of control measures vitally important. We treated relatively undisturbed, native, forested sites of 10% to 15% slope with surfactant and used a rain-fall simulator to investigate the effects of repellency. We compared infiltration measurements made by the simulator and a mini-disk infiltrometer (MDI). Runoff was produced by all plots with untreated water, but only two of 12 plots with surfacta...

  12. Repellent activity of desiccant dusts and conidia of the entomopathogenic fungus Beauveria bassiana when tested against poultry red mites (Dermanyssus gallinae) in laboratory experiments

    DEFF Research Database (Denmark)

    Kilpinen, Ole; Steenberg, Tove

    2016-01-01

    on both dose and relative humidity (RH). However, one desiccant dust was significantly less repellent compared to other dusts with similar levels of efficacy. Further, dry conidia of the fungus Beauveria bassiana were also shown to be repellent to poultry red mites, both when applied on its own and when...

  13. Greek Pinus essential oils: larvicidal activity and repellency against Aedes albopictus (Diptera: Culicidae).

    Science.gov (United States)

    Koutsaviti, Katerina; Giatropoulos, Athanassios; Pitarokili, Danae; Papachristos, Dimitrios; Michaelakis, Antonios; Tzakou, Olga

    2015-02-01

    The needle volatiles metabolites of seven Pinus spp.: Pinus nigra (3 samples), Pinus stankewiczii, Pinus brutia, Pinus halepensis, Pinus canariensis, Pinus pinaster and Pinus strobus from Greece were determined by gas chromatography and gas chromatography-mass spectrometry. P. nigra and P. canariensis essential oils were dominated by α-pinene (24.9-28.9 % and 15 %, respectively) and germacrene D (20.3-31.9 % and 55.8 %, respectively), whereas P. brutia and P. strobus by α-pinene (20.6 % and 31.4 %, respectively) and β-pinene (31.7 % and 33.6 %, respectively). P. halepensis and P. pinaster oils were characterized by β-caryophyllene (28.5 % and 22.5 %, respectively). Finally, β-pinene (31.4 %), germacrene D (23.3 %) and α-pinene (17.5 %) were the most abundant compounds in the needle oil of P. stankewiczii. Additionally the larvicidal and repellent properties of their essential oils were evaluated against Aedes albopictus, a mosquito of great ecological and medical importance. The results of bioassays revealed that repellent abilities of the tested essential oils were more potent than their larvicidal activities. The essential oils of P. brutia, P. halepensis and P. stankewiczii presented considerable larvicidal activity (LC50 values 67.04 mgL(-1) and 70.21 mgL(-1), respectively), while the others were weak to inactive against larvae. The essential oils of P. halepensis, P. brutia, and P. stankewiczii presented a high repellent activity, even at the dose of 0.2 μL cm(-2), while in the dose of 0.4 μL cm(-2), almost all the tested EOs displayed protection against the mosquito.

  14. What Happens to Blood Glucose Concentrations After Oral Treatment for Neonatal Hypoglycemia?

    Science.gov (United States)

    Harris, Deborah L; Gamble, Greg D; Weston, Philip J; Harding, Jane E

    2017-11-01

    To determine the change in blood glucose concentration after oral treatment of infants with hypoglycemia in the first 48 hours after birth. We analyzed data from 227 infants with hypoglycemia (blood glucose dextrose or placebo gel plus feeding with formula, expressed breast milk, or breast feeding. The overall mean increase in blood glucose concentration was 11.7 mg/dL (95% CI 10.4-12.8). The increase was greater after buccal dextrose gel than after placebo gel (+3.0 mg/dL; 95% CI 0.7-5.3; P = .01) and greater after infant formula than after other feedings (+3.8 mg/dL; 95% CI 0.8-6.7; P = .01). The increase in blood glucose concentration was not affected by breast feeding (+2.0 mg/dL; 95% CI -0.3 to 44.2; P = .09) or expressed breast milk (-1.4 mg/dL; 95% CI -3.7 to 0.9; P = .25). However, breast feeding was associated with reduced requirement for repeat gel treatment (OR = 0.52; 95% CI 0.28-0.94; P = .03). Treatment of infants with hypoglycemia with dextrose gel or formula is associated with increased blood glucose concentration and breast feeding with reduced need for further treatment. Dextrose gel and breast feeding should be considered for first-line oral treatment of infants with hypoglycemia. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Thermal repellent properties of surface coating using silica

    Science.gov (United States)

    Lee, Y. Y.; Halim, M. S.; Aminudin, E.; Guntor, N. A.

    2017-11-01

    Extensive land development in urban areas is completely altering the surface profile of human living environment. As cities growing rapidly, impervious building and paved surfaces are replacing the natural landscape. In the developing countries with tropical climate, large masses of building elements, such as brick wall and concrete members, absorb and store large amount of heat, which in turn radiate back to the surrounding air during the night time. This bubble of heat is known as urban heat island (UHI). The use of high albedo urban surfaces is an inexpensive measure that can reduce surrounded temperature. Thus, the main focus of this study is to investigate the ability of silica, SiO2, with high albedo value, to be used as a thermal-repelled surface coating for brick wall. Three different silica coatings were used, namely silicone resin, silicone wax and rain repellent and one exterior commercial paint (jota shield paint) that commercially available in the market were applied on small-scale brick wall models. An uncoated sample also had been fabricated as a control sample for comparison. These models were placed at the outdoor space for solar exposure. Outdoor environment measurement was carried out where the ambient temperature, surface temperature, relative humidity and UV reflectance were recorded. The effect of different type of surface coating on temperature variation of the surface brick wall and the thermal performance of coatings as potential of heat reduction for brick wall have been studied. Based on the results, model with silicone resin achieved the lowest surface temperature which indicated that SiO2 can be potentially used to reduce heat absorption on the brick wall and further retains indoor passive thermal comfortability.

  16. GC×GC-TOFMS Analysis of Essential Oils Composition from Leaves, Twigs and Seeds of Cinnamomum camphora L. Presl and Their Insecticidal and Repellent Activities.

    Science.gov (United States)

    Jiang, Hao; Wang, Jin; Song, Li; Cao, Xianshuang; Yao, Xi; Tang, Feng; Yue, Yongde

    2016-03-28

    Interest in essential oils with pesticidal activity against insects and pests is growing. In this study, essential oils from different parts (leaves, twigs and seeds) of Cinnamomum camphora L. Presl were investigated for their chemical composition, and insecticidal and repellent activities against the cotton aphid. The essential oils, obtained by hydrodistillation, were analyzed by GC×GC-TOFMS. A total of 96 components were identified in the essential oils and the main constituents found in the leaves and twigs were camphor, eucalyptol, linalool and 3,7-dimethyl-1,3,7-octatriene. The major components found in the seeds were eucalyptol (20.90%), methyleugenol (19.98%), linalool (14.66%) and camphor (5.5%). In the contact toxicity assay, the three essential oils of leaves, twigs and seeds exhibited a strong insecticidal activity against cotton aphids with LC50 values of 245.79, 274.99 and 146.78 mg/L (after 48 h of treatment), respectively. In the repellent assay, the highest repellent rate (89.86%) was found in the seed essential oil at the concentration of 20 μL/mL after 24 h of treatment. Linalool was found to be a significant contributor to the insecticidal and repellent activities. The results indicate that the essential oils of C. camphora might have the potential to be developed into a natural insecticide or repellent for controlling cotton aphids.

  17. The effects of forced-egg retention on the blood-feeding behavior and reproductive potential of Culex pipiens (Diptera: Culicidae).

    Science.gov (United States)

    Johnson, Brian J; Fonseca, Dina M

    2014-07-01

    High rates of West Nile virus (WNV) transmission to humans are associated with exceptionally hot and dry summers. This is paradoxical since the eggs of Culex vectors of WNV depend on the persistence of containers with water, which decline during droughts. We examined the effects of forced-egg retention on the reproductive success of female Culex pipiens as well as behavioral responses, such as likelihood of secondary blood meals. As controls we examined the effects of female age and delayed mating. We found that early mating is essential to achieve reproductive success and, consistent with an "all-or-none" ovipositing strategy, C. pipiens females are able to retain considerable reproductive potential while searching for oviposition sites. Specifically, although forced-egg retention resulted in significant decreases in fitness, the decline was moderate for 5 weeks and most can be accounted for by increases in female age. Consequently, no females took blood more than once per gonotrophic cycle, which eliminates the possibility that heightened vectorial capacity due to multiple blood-feedings increases WNV transmission during periods of drought. Instead, our findings suggest that during droughts populations of C. pipiens have time to locate the remaining water holes, which are associated with human populations and WNV-competent bird species. Copyright © 2014. Published by Elsevier Ltd.

  18. A simple and affordable membrane-feeding method for Aedes aegpyti and Anopheles minimus (Diptera: Culicidae).

    Science.gov (United States)

    Finlayson, Catherine; Saingamsook, Jassada; Somboon, Pradya

    2015-12-01

    This study developed an artificial feeding (AF) method to replace direct host feeding (DHF) for the maintenance of Aedes aegypti and Anopheles minimus mosquito colonies. The procedure can be adopted by all laboratories due to its simple and affordable materials and design. The apparatus consists of heparinized cow blood contained in a 5cm diameter glass petri dish with 5cm(2) Parafilm M (Bemis(®)) stretched thinly over the top, with a pre-heated bag of vegetable oil placed underneath to keep the blood warm. Both parts are contained within an insulated Styrofoam™ box with a hole in the lid for mosquitoes to access the membrane. Mosquitoes are fed by AF for 15min at a time. Feeding rate and fecundity of Ae. aegypti mosquitoes feeding on the AF device were compared to those feeding on a live rat (DHF(r)), and of Anopheles minimus mosquitoes feeding on the AF device compared to those feeding on a human arm (DHF(h)). Aedes aegypti mosquitoes fed by AF or DHF(r) had similar feeding rates (38.2±21.5% and 35.7±18.2%, respectively) and overall egg production (1.5% difference). Anopheles minimus mosquitoes fed by the AF method had a lower feeding rate (52.0±1.0% for AF compared to 70.7±20.2% for DHF(h)) and overall egg production (40% reduction compared to DHF(h)). However, the number of eggs produced by AF-fed mosquitoes (1808 eggs per 100 mosquitoes) was still sufficient for colony maintenance, and with increased feeding time both parameters are expected to increase. Reduced feeding rate and overall egg production was observed when Ae. aegypti mosquitoes were fed on blood refrigerated for over two weeks. In conclusion, an AF device has been developed which can replace DHF for Ae. aegypti and An. minimus colony maintenance when using blood refrigerated for a maximum of two weeks. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Distribution flow: a general process in the top layer of water repellent soils

    NARCIS (Netherlands)

    Ritsema, C.J.; Dekker, L.W.

    1995-01-01

    Distribution flow is the process of water and solute flowing in a lateral direction over and through the very first millimetre or centimetre of the soil profile. A potassium bromide tracer was applied in two water-repellent sandy soils to follow the actual flow paths of water and solutes in the

  20. Repellency and toxicity of three Impatients species (Balsaminaceae) extracts on Myzus persicae Sulzer (Homoptera: Aphididae)

    Czech Academy of Sciences Publication Activity Database

    Pavela, R.; Vrchotová, Naděžda; Šerá, Božena

    2009-01-01

    Roč. 2009, - (2009), s. 48-51 ISSN 0974-391X R&D Projects: GA MZe(CZ) QH72117 Institutional research plan: CEZ:AV0Z60870520 Keywords : Impatiens * repellency * toxicity Subject RIV: EH - Ecology, Behaviour

  1. Protection of Grain Products from Sitophilus oryzae (L.) Contamination by Anti-Insect Pest Repellent Sachet Containing Allyl Mercaptan Microcapsule.

    Science.gov (United States)

    Chang, Yoonjee; Lee, Soo-Hyun; Na, Ja Hyun; Chang, Pahn-Shick; Han, Jaejoon

    2017-11-01

    The purpose of this study was to develop an anti-insect pest repellent sachet to prevent Sitophilus oryzae (L.) (Coleoptera: Curculionidae) contamination in grain packaging. The anti-insect pest activities of essential oils (EOs) from garlic (Allium Sativum), ginger (Zingiber Officinalis), black pepper (Piper nigrum), onion (Allium cepa), and fennel (Foeniculum vulgare) as well as major compounds (allyl disulfide, AD; allyl mercaptan, AM) isolated from of garlic and onion (AD and AM) were measured against S. oryzae. The results revealed that garlic EO, onion EO, AD, and AM showed strong fumigant insecticidal activities. Among these, AM showed the highest acetylcholinesterase (AChE) inhibition rate, indicating that the fumigation insecticidal efficacy of AM is related with its AChE inhibition ability. Subsequently, the microcapsules were produced with a high efficiency (80.02%) by using AM as a core material and rice flour as a wall material. Finally, sachet composed of rice flour microcapsule containing 2% AM (RAM) was produced. Repellent assay was performed to measure anti-insect pest ability of the RAM sachet, showed remarkable repelling effect within 48 h both in the presence or absence of attractant. In a release profile of RAM sachet, it was expected to last over 20 mo during the distribution period of brown rice. Moreover, RAM sachet showed no undesirable changes to the sensory properties of the rice both before and after cooking. Taken together, these results suggest that the newly developed RAM sachet could be used as a packaging material to protect grain products from S. oryzae contamination. The rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae), causes damages to stored products and its contamination in grain products has become a major problem in cereal market. To preserve brown rice, an anti-insect pest repellent sachet containing 2% allyl mercaptan was newly developed and it showed remarkable repellent abilities against S. oryzae. It

  2. Efficacy of topical mosquito repellent (picaridin) plus long-lasting insecticidal nets versus long-lasting insecticidal nets alone for control of malaria : A cluster randomised controlled trial

    NARCIS (Netherlands)

    Sluydts, V.; Durnez, L.; Heng, S.; Gryseels, C.; Canier, L.; Kim, S.; Van Roey, K.; Kerkhof, K.; Khim, N.; Mao, S.; Menard, D.; Coosemans, M.

    2016-01-01

    Background Although effective topical repellents provide personal protection against malaria, whether mass use of topical repellents in addition to long-lasting insecticidal nets can contribute to a further decline of malaria is not known, particularly in areas where outdoor transmission occurs. We

  3. Rumen fermentation, blood metabolites, and growth performance of calves during transition from liquid to solid feed: Effects of dietary level and particle size of alfalfa hay.

    Science.gov (United States)

    Nemati, M; Amanlou, H; Khorvash, M; Moshiri, B; Mirzaei, M; Khan, M A; Ghaffari, M H

    2015-10-01

    This study evaluated the effects of particle size (PS) and dietary level of alfalfa hay (AH) on rumen fermentation parameters, blood metabolites, eating behavior, and growth performance in dairy calves during transition from liquid to solid feed. Sixty newborn dairy calves (41 ± 2.5,kg of body weight) were used in a 2 × 2 factorial arrangement with the factors dietary AH level (medium, 12.5%, or high, 25%, on DM basis) and PS (fine = 1mm or medium = 3mm, as geometric means) of AH. Hence, the dietary treatments were (1) medium level of AH with fine PS (M-FPS), (2) medium level of AH with medium PS (M-MPS), (3) high level of AH with fine PS (H-FPS), and (4) high level of AH with medium PS (H-MPS). Particle size of AH did not affect total DMI (TDMI) during the preweaning period, although TDMI was greater for calves fed MPS than in those fed FPS during the postweaning and overall periods. Calves fed MPS spent more time eating solid feed and ruminating and less time on nonnutritive oral behaviors compared with FPS calves. The dietary level of AH did not affect behavioral parameters. Average daily gain of calves was not affected by dietary treatment before weaning. During the postweaning and overall periods, average daily gain was greater in calves fed MPS than in those fed FPS at the 25% AH level, but this effect was absent with 12.5% AH. Furthermore, the rumen pH values on d 35 and 70 of the study were greater for MPS than for FPS, regardless of the dietary level of AH. Effects of AH level, PS, and their interaction did not affect blood glucose concentrations in developing calves. These results indicate that feed intake, feeding behavior, rumen fermentation parameters, and blood β-hydroxybutyrate concentration may be affected by rations differing in forage PS; thus, providing calves with MPS can improve calf performance and reduce their nonnutritive oral behaviors. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  4. [The merit of using untreated, HCl-treated amd partly-hydrolyzed straw meal in the feeding regime for piglets after early weaning. 3. Parameters of protein, fat, carbohydrates and mineral metabolism in the blood serum of the piglet].

    Science.gov (United States)

    Münchow, H

    1989-10-01

    In parallel studies with piglets of the country race the applicability of variously treated straw materials was tested in comparison with the conventional feeding of concentrate (I) after an early weaning date (30th-35th day of life) over a feeding period of 8 weeks (1st-8th week of keeping). In the rations containing 10% straw (concentrate-straw mixtures), untreated (II), HCl treated (III:HCl treatment without steaming) and partly hydrolyzed straw meal (IV:HCl treatment with subsequent steaming) were tested. In the 2nd and 8th weeks of keeping blood samples were taken from 4 animals of each group and selected parameters of the protein, fat, carbohydrate and mineral metabolism were subsequently ascertained from the blood serum. About half of the total of the 13 selected parameters showed reactions of the intermediary metabolism of the test groups caused by the feeding. With the parameters on the whole varying in the normal physiologic range, a decrease in the blood urea and creatinine concentration and an increase in the blood glucose level were detected after the use of the concentrate-straw mixtures (III and IV) in comparison with the sole feeding of concentrate (I) and partly also in comparison with untreated straw meal (II), their intensity varying in dependence on feeding and test duration. Particularly towards the end of the experiment, an increase of the activity of alkaline phosphatase was also characteristic, which was in negative correlation with the P content of the serum and in positive correlation with growth performance. The physiologic parameters are discussed in connection with the higher growth performance at reduced concentrate expenditure achieved in III and IV in comparison to I and II.

  5. Feeding different dietary protein to energy ratios to Holstein heifers: effects on growth performance, blood metabolites and rumen fermentation parameters.

    Science.gov (United States)

    Dong, L F; Zhang, W B; Zhang, N F; Tu, Y; Diao, Q Y

    2017-02-01

    Eighteen Chinese Holstein heifers average age 230 ± 14 days were allocated to 1 of 3 dietary crude protein (CP) to metabolizable energy (ME) ratios to examine the effects on growth performance, blood metabolites and rumen fermentation parameters with 90-days experiment. Three different dietary CP:ME ratios were targeted based on the formulation of dietary CP contents of 10.85%, 12.78% and 14.63% on dry matter (DM) basis with similar ME contents (10.42 MJ/kg DM), which were categorized as low, medium and high dietary CP:ME ratios. The actual CP:ME ratios obtained in this study significantly increased from low to high CP:ME ratio groups with a value of 10.59, 11.83 and 13.38 g/MJ respectively. Elevated CP:ME ratios significantly increased CP intake (kg/day) and feed efficiency (FE) which was defined as dry matter intake as a proportion of average daily gain (ADG), whereas little difference was observed in body weight (kg), ADG (kg/day), DM intake (kg/day) and ME intake (MJ/day) among the three different CP:ME ratio groups. Increasing dietary CP to ME ratios significantly increased CP digestibility, whereas digestibility of DM and gross energy remained constant in the current experiment. Blood urea nitrogen and insulin-like growth factor-1 linearly increased with increasing dietary CP:ME ratios. There was significantly dietary treatment effect on rumen fermentation parameters including acetate, propionate, butyrate and total volatile fatty acids. Therefore, this study indicated that increasing dietary CP levels with similar energy content contributed to increased protein intake and its digestibility, as well as FE. Holstein heifers between 200 and 341 kg subjected to 13.38 dietary CP:ME ratio showed improved feed efficiency, nutrient digestibility, some blood metabolites and rumen fermentation characteristics for 0.90 kg/day rate of gain. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

  6. Deposition of chemically reactive and repellent sites on biosensor chips for reduced non-specific binding.

    Science.gov (United States)

    Gandhiraman, R P; Gubala, V; Le, N C H; Nam, Le Cao Hoai; Volcke, C; Doyle, C; James, B; Daniels, S; Williams, D E

    2010-08-01

    The performances of new polymeric materials with excellent optical properties and good machinability have led the biomedical diagnostics industry to develop cheap disposable biosensor platforms appropriate for point of care applications. Zeonor, a type of cycloolefin polymer (COP), is one such polymer that presents an excellent platform for biosensor chips. These polymer substrates have to be modified to have suitable physico-chemical properties for immobilizing proteins. In this work, we have demonstrated the amine functionalization of COP substrates, by plasma enhanced chemical vapour deposition (PECVD), through codeposition of ethylene diamine and 3-aminopropyltriethoxysilane precursors, for building chemistries on the plastic chip. The elemental composition, adhesion, ageing and reactivity of the plasma polymerized film were examined. The Si-O functionality present in amino silane contributed for a good interfacial adhesion of the coating to COP substrates and also acted as a network building layer for plasma polymerization. Wet chemical modification was then carried out on the amine functionalized chips to create chemically reactive isothiocyanate sites and protein repellent fluorinated sites on the same chip. The density of the reactive and repellent sites was altered by choosing appropriate mixtures of homofunctional phenyldiisothiocyanate (PDITC), pentafluoroisothiocyanate (5FITC) and phenylisothiocyanate (PITC) compounds. By tailoring the density of reactive binding sites and protein repellent sites, the non-specific binding of ssDNA has been decreased to a significant extent. Copyright 2010 Elsevier B.V. All rights reserved.

  7. Effect of propolis feeding on rat tissues damaged by X-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Hoon; Seo, Eul Won [Andong National Univ., Andong (Korea, Republic of); Ji, Tae Jeong [Kaya Univ., Goryeong (Korea, Republic of)

    2007-06-15

    Present study aimed to investigate the radioprotective effects of propolis feeding on rat tissues damaged by X-ray irradiation. It was shown that the number of white blood cell in X-ray irradiated group supplemented with propolis increased as much to those of the control group and also the GOT activities among the blood components were decreased after propolis feeding. The mineral contents such as Mg, Fe, Ca, Mn, Cu, Mo, Ni, As in liver were increased as compared with those of the control group but maintained lower level than those of only irradiated groups, implying that the propolis feeding elevated the recovery capability of white blood cell effectively and propolis have a potential resistance to cell damage by X-ray. According to histological observations of the testis, intestine and liver tissues which are irradiated after feeding propolis, the numbers of damaged undifferentiated cells were decreased in testis and the shape of the goblet cells and inner and outer muscular layers in intestine were restored to the original state and the hepatocytes and interlobular veins were shown intact in liver, suggesting that propolis has a potential capacity to restore cell shapes or resist deformation of cell.

  8. Essential oil composition, adult repellency and larvicidal activity of eight Cupressaceae species from Greece against Aedes albopictus (Diptera: Culicidae).

    Science.gov (United States)

    Giatropoulos, Athanassios; Pitarokili, Danae; Papaioannou, Fotini; Papachristos, Dimitrios P; Koliopoulos, George; Emmanouel, Nickolaos; Tzakou, Olga; Michaelakis, Antonios

    2013-03-01

    The present study evaluated leaf essential oils from eight Cupresaceae species; Cupressus arizonica, Cupressus benthamii, Cupressus macrocarpa, Cupressus sempervirens, Cupressus torulosa, Chamaecyparis lawsoniana, Juniperus phoenicea, and Tetraclinis articulata for their larvicidal and repellent properties against Aedes albopictus, a mosquito of great ecological and medical importance. Based on the LC(50) values, C. benthamii essential oil was the most active (LC(50) = 37.5 mg/L) while the other tested Cupressaceae essential oils provided rather moderate toxicity against larvae (LC(50) = 47.9 to 70.6 mg/L). Under the used laboratory conditions, three of the essential oils (C. benthamii, C. lawsoniana, and C. macrocarpa) provided sufficient protection against mosquito adults, equivalent to the standard repellent "Deet" in the 0.2 mg/cm(2) dose, while C. macrocarpa assigned as the superior repellent oil in the 0.08 mg/cm(2) dose. Chemical analysis of the essential oils using gas chromatography and gas chromatography-mass spectrometry revealed the presence of 125 components.

  9. Herbivore-induced poplar cytochrome P450 enzymes of the CYP71 family convert aldoximes to nitriles which repel a generalist caterpillar.

    Science.gov (United States)

    Irmisch, Sandra; Clavijo McCormick, Andrea; Günther, Jan; Schmidt, Axel; Boeckler, Gerhard Andreas; Gershenzon, Jonathan; Unsicker, Sybille B; Köllner, Tobias G

    2014-12-01

    Numerous plant species emit volatile nitriles upon herbivory, but the biosynthesis as well as the relevance of these nitrogenous compounds in plant-insect interactions remains unknown. Populus trichocarpa has been shown to produce a complex blend of nitrogenous volatiles, including aldoximes and nitriles, after herbivore attack. The aldoximes were previously reported to be derived from amino acids by the action of cytochrome P450 enzymes of the CYP79 family. Here we show that nitriles are derived from aldoximes by another type of P450 enzyme in P. trichocarpa. First, feeding of deuterium-labeled phenylacetaldoxime to poplar leaves resulted in incorporation of the label into benzyl cyanide, demonstrating that poplar volatile nitriles are derived from aldoximes. Then two P450 enzymes, CYP71B40v3 and CYP71B41v2, were characterized that produce aliphatic and aromatic nitriles from their respective aldoxime precursors. Both possess typical P450 sequence motifs but do not require added NADPH or cytochrome P450 reductase for catalysis. Since both enzymes are expressed after feeding by gypsy moth caterpillars, they are likely to be involved in herbivore-induced volatile nitrile emission in P. trichocarpa. Olfactometer experiments showed that these volatile nitriles have a strong repellent activity against gypsy moth caterpillars, suggesting they play a role in induced direct defense against poplar herbivores. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

  10. The determination of the concentrations of Isoforms of Vitamin E in tissues, milk and blood via High-Performance Liquid Chromatography (HPLC) after short-term feeding in dairy cows

    Science.gov (United States)

    The objective of this study was to determine the pattern of change in the concentrations of the four isoforms of vitamin E (alpha-, beta-, gamma- and delta-tocopherol) in bovine tissues (liver, mammary and muscle), blood and milk after short-term feeding of a vegetable-derived oil (Tmix) particularl...

  11. Repellent activity of desiccant dusts and conidia of the entomopathogenic fungus Beauveria bassiana when tested against poultry red mites (Dermanyssus gallinae) in laboratory experiments.

    Science.gov (United States)

    Kilpinen, Ole; Steenberg, Tove

    2016-11-01

    Desiccant dusts and entomopathogenic fungi have previously been found to hold potential against the poultry red mite, which is an important pest in egg production and notoriously difficult to control. Both control agents may cause repellence in other arthropods and potentially also influence control levels adversely when used against the poultry red mite. Five desiccant dust products with good efficacy against the poultry red mite Dermanyssus gallinae caused avoidance behavior in mites when tested in bioassays. The repellent activity was correlated with efficacy, which was found to depend on both dose and relative humidity (RH). However, one desiccant dust was significantly less repellent compared to other dusts with similar levels of efficacy. Further, dry conidia of the fungus Beauveria bassiana were also shown to be repellent to poultry red mites, both when applied on its own and when admixed with a low dose of the desiccant dust Diamol. The pick-up of desiccant dust particles and fungus conidia from treated surfaces by mites did not differ depending on RH, whereas the overall efficacy of the two control agents were significantly higher at 75 than at 85 % RH. In addition, the combined effect of the two substances was synergistic when tested in a bioassay where mites could choose whether to cross a treated surface. This is the first time a member of Acari has been shown to be repelled by desiccant dusts and by conidia of an entomopathogenic fungus.

  12. Growth performance, feeding behavior, and selected blood metabolites of Holstein dairy calves fed restricted amounts of milk: No interactions between sources of finely ground grain and forage provision.

    Science.gov (United States)

    Mirzaei, M; Khorvash, M; Ghorbani, G R; Kazemi-Bonchenari, M; Ghaffari, M H

    2017-02-01

    The objective of this study was to investigate the effects of grain sources and forage provision on growth performance, blood metabolites, and feeding behaviors of dairy calves. Sixty 3-d-old Holstein dairy calves (42.2 ± 2.5 kg of body weight) were used in a 2 × 3 factorial arrangement with the factors being grain sources (barley and corn) and forage provision (no forage, alfalfa hay, and corn silage). Individually housed calves were randomly assigned (n = 10 calves per treatment: 5 males and 5 females) to 6 treatments: (1) barley grain (BG) without forage supplement, (2) BG with alfalfa hay (AH) supplementation, (3) BG with corn silage (CS) supplementation, (4) corn grain (CG) without forage supplement, (5) CG with AH supplementation, and (6) CG with CS supplementation. All calves had ad libitum access to water and starter feed throughout the experiment. All calves were weaned on d 49 and remained in the study until d 63. Starter feed intake and average daily gain (ADG) was greater for calves fed barley than those fed corn during the preweaning and overall periods. Calves supplemented with CS had greater final body weight and postweaning as well as overall starter feed intake than AH and non-forage-supplemented calves. During the preweaning and overall periods, feeding of CS was found to increase ADG compared with feeding AH and nonforage diets. However, feed efficiency was not affected by dietary treatments. Calves supplemented with CS spent more time ruminating compared with AH and control groups; nonnutritive oral behaviors were the greatest in non-forage-supplemented calves. Regardless of the grain sources, the rumen pH value was greater for AH calves compared with CS and non-forage-supplemented calves. Blood concentration of BHB was greater for CS-supplemented calves compared with AH and non-forage-supplemented calves. Furthermore, body length and heart girth were greater for calves fed barley compared with those fed corn, and also in forage

  13. Repellent activity of herbal essential oils against Aedes aegypti (Linn. and Culex quinquefasciatus (Say.

    Directory of Open Access Journals (Sweden)

    Duangkamon Sritabutra

    2013-08-01

    Full Text Available Objective: To determine the mosquito repellent activity of herbal essential oils against female Aedes aegypti and Culex quinquefasciatus. Methods: On a volunteer’s forearm, 0.1 mL of each essential oil was applied to 3 cm伊10 cm of exposed skin. The protection time was recorded for 3 min after every 30 min. Results: Essential oil from clove oil in olive oil and in coconut oil gave the longest lasting period of 76.50 min and 96.00 min respectively against Aedes aegypti. The citronella grass oil in olive oil, citronella grass oil in coconut oil and lemongrass oil in coconut oil exhibited protection against Culex quinquefasciatus at 165.00, 105.00, and 112.50 min respectively. Conclusions: The results clearly indicated that clove, citronella and lemongrass oil were the most promising for repellency against mosquito species. These oils could be used to develop a new formulation to control mosquitoes.

  14. Larvicidal and repellent effect of some Tribulus terrestris L., (Zygophyllaceae extracts against the dengue fever mosquito, Aedes aegypti (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Tarek M.Y. El-Sheikh

    2016-01-01

    Full Text Available Aedes aegypti transmits etiologic agents of yellow fever and dengue. Vaccine for dengue virus is not available and vector control is essential to minimize dengue incidence. The larvicidal and repellent effect of the crude ethanol, acetone and petroleum ether extract leaves of Tribulus terrestris, against 3rd instar larvae and adults of mosquito, Ae. aegypti the vector of dengue fever was evaluated. The efficacy of petroleum ether extract seemed to be more effective with LC50 64.6 ppm followed by acetone extract with LC50 173.2 ppm and finally ethanolic extract with LC50 376.4 ppm. Moreover, the acetone and petroleum ether extracts exerted a highly delayed toxic effect on the pupae and adults resulted from treated larvae, where the pupal mortality was 57.1% and 100% at concentrations 400 and 100 ppm, respectively. Also, the petroleum ether and acetone extracts showed reduction effects on adult emergence. The repellent action of the plant extracts tested was varied depending on the solvent used in extraction and the dose of the extract. The most effective plant extract that evoked 100% repellency or biting deterrence was petroleum ether extract at a dose of 1.5 mg/cm2 compared with 100% repellency for commercial formulation, N,N-diethyl-3-methylbenzamide (DEET at the same dose. Hence, these extracts can be used as an effective alternative to the existing synthetic pesticides for the control of Ae. aegypti.

  15. Functional anatomy of vagina muscles in the blood-feeding insect, Rhodnius prolixus.

    Science.gov (United States)

    Chiang, R G; O'Donnell, M J

    2009-11-01

    The physiology of the muscles associated with the vagina in the blood-feeding insect, Rhodnius prolixus Stal, was investigated with the use of Methylene Blue staining to visualize the anatomy, and a micro force transducer to record spontaneous and neurally-evoked contractions. The vagina is associated with a dorsal muscle and a set of paired lateral muscles. The dorsal muscle extends from the base of the common oviduct to apodemes located laterally on sternite VIII, the first genital segment. The lateral muscles extend from a medially-located apodeme on the posterior edge of sternite VI around each side of the common oviduct to travel posteriorly along the side of the vagina before inserting laterally on apodemes on sternite VIII. The vagina muscles display spontaneous and neurally-evoked contractions that are prolonged but transient. The response to evoked contractions shows that the muscles are innervated by both excitatory and inhibitory motor axons. The degree of tension generated by evoked contractions is dependent on the frequency of stimulation with maximal tension being generated at 20-30Hz. This tension, which often exceeds 400mg, is transient and returns to a baseline within 1 to 2min during continuous stimulation. These results, which are the first to describe this chamber in this well-studied insect, are discussed with respect to the act of egg laying.

  16. Super Water-Repellent Fractal Surfaces of a Photochromic Diarylethene Induced by UV Light

    Science.gov (United States)

    Izumi, Norikazu; Minami, Takayuki; Mayama, Hiroyuki; Takata, Atsushi; Nakamura, Shinichiro; Yokojima, Satoshi; Tsujii, Kaoru; Uchida, Kingo

    2008-09-01

    Photochromic diarylethene forms super water-repellent surfaces upon irradiation with UV light. Microfibril-like crystals grow on the solid diarylethene surface after UV irradiation, and the contact angle of water on the surface becomes larger with increasing surface roughness with time. The fractal analysis was made by the box-counting method for the rough surfaces. There are three regions in the roughness size having the fractal dimension of ca. 2.4 (size of roughness smaller than 5 µm), of ca. 2.2 (size of roughness between 5-40 µm), and of ca. 2.0 (size of roughness larger than 40 µm). The fractal dimension of ca. 2.4 was due to the fibril-like structures generated gradually by UV irradiation on diarylethene surfaces accompanied with an increase in the contact angle. The surface structure with larger fractal dimension mainly contributes to realizing the super water-repellency of the diarylethene surfaces. This mechanism of spontaneous formation of fractal surfaces is similar to that for triglyceride and alkylketene dimer waxes.

  17. Repellent Activity of Botanical Oils against Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Kuhns, Emily H; Martini, Xavier; Hoyte, Angel; Stelinski, Lukasz L

    2016-07-14

    The Asian citrus psyllid, Diaphorina citri Kuwayama, is the insect vector of the pathogen causing huanglongbing. We selected three botanical oils to evaluate behavioral activity against D. citri. In laboratory olfactometer assays, fir oil was repellent to D. citri females, while litsea and citronella oils elicited no response from D. citri females. In choice settling experiments, D. citri settled almost completely on control plants rather than on plants treated with fir oil at a 9.5 mg/day release rate. Therefore, we conducted field trials to determine if fir oil reduced D. citri densities in citrus groves. We found no repellency of D. citri from sweet orange resets that were treated with fir oil dispensers releasing 10.4 g/day/tree as compared with control plots. However, we found a two-week decrease in populations of D. citri as compared with controls when the deployment rate of these dispensers was doubled. Our results suggest that treatment of citrus with fir oil may have limited activity as a stand-alone management tool for D. citri and would require integration with other management practices.

  18. The Influence of Insecticide Resistance, Age, Sex, and Blood Feeding Frequency on Thermal Tolerance of Wild and Laboratory Phenotypes of Anopheles funestus (Diptera: Culicidae).

    Science.gov (United States)

    Lyons, C L; Oliver, S V; Hunt, R H; Coetzee, M

    2016-03-01

    Resistance to insecticides is a global phenomenon and is increasing at an unprecedented rate. How resistant and susceptible strains of malaria vectors might differ in terms of life history and basic biology is often overlooked, despite the potential importance of such information in light of changing climates. Here, we investigated the upper thermal limits (ULT50) of wild and laboratory strains of Anopheles funestus Giles mosquitoes, including resistance status, sex, age, and blood feeding status as potential factors influencing ULT50. No significant differences in ULT50 were observed between strains displaying different resistance patterns, nor was there a significant difference between wild and laboratory strains. In some instances, strains showed a senescence response, displaying decreased ULT50 with an increase in age, and differences between males and females (females displaying higher ULT50 than males). Blood feeding did not seem to influence ULT50 in any way. For An. funestus, it seems evident that there is no cost to resistance despite what is displayed in other anopheline species. This could have significant impacts for vector control, with resistant populations of An. funestus performing just as well, if not better, than susceptible strains, especially under changing environmental conditions such as those expected to occur with climate change.

  19. Pesticide-contaminated feeds in integrated grass carp aquaculture: toxicology and bioaccumulation.

    Science.gov (United States)

    Pucher, J; Gut, T; Mayrhofer, R; El-Matbouli, M; Viet, P H; Ngoc, N T; Lamers, M; Streck, T; Focken, U

    2014-02-19

    Effects of dissolved pesticides on fish are widely described, but little is known about effects of pesticide-contaminated feeds taken up orally by fish. In integrated farms, pesticides used on crops may affect grass carp that feed on plants from these fields. In northern Vietnam, grass carp suffer seasonal mass mortalities which may be caused by pesticide-contaminated plants. To test effects of pesticide-contaminated feeds on health and bioaccumulation in grass carp, a net-cage trial was conducted with 5 differently contaminated grasses. Grass was spiked with 2 levels of trichlorfon/fenitrothion and fenobucarb. Unspiked grass was used as a control. Fish were fed at a daily rate of 20% of body mass for 10 d. The concentrations of fenitrothion and fenobucarb in pond water increased over time. Effects on fish mortality were not found. Fenobucarb in feed showed the strongest effects on fish by lowering feed uptake, deforming the liver, increasing blood glucose and reducing cholinesterase activity in blood serum, depending on feed uptake. Fenobucarb showed increased levels in flesh in all treatments, suggesting bio-concentration. Trichlorfon and fenitrothion did not significantly affect feed uptake but showed concentration-dependent reduction of cholinesterase activity and liver changes. Fenitrothion showed bioaccumulation in flesh which was dependant on feed uptake, whereas trichlorfon was only detected in very low concentrations in all treatments. Pesticide levels were all detected below the maximum residue levels in food. The pesticide-contaminated feeds tested did not cause mortality in grass carp but were associated with negative physiological responses and may increase susceptibility to diseases.

  20. Host feeding pattern of Japanese encephalitis virus vector mosquitoes (Diptera: Culicidae) from Kuttanadu, Kerala, India.

    Science.gov (United States)

    Philip Samuel, P; Arunachalam, N; Hiriyan, J; Tyagi, B K

    2008-09-01

    Identification of blood meals of vector mosquitoes is an important tool in the epidemiological investigations of vector-borne diseases. The blood meals of three mosquito species involved in the transmission of Japanese encephalitis virus (JEV) from the Kuttanadu area, Kerala, were determined using the agarose gel diffusion technique. A total of 4959 blood smears belonging to Culex (Culex) tritaeniorhynchus Giles (3273), Cx. (Culex) gelidus Theobald (64), Mansonia (Mnd.) indiana Edwards (735) ,and Ma. (Mnd.) uniformis (Theobald) (887) were tested. Cx. tritaeniorhynchus had predominantly fed on bovids (46.4%), and a good proportion (29%) had fed on more than one host. Cx. tritaeniorhynchus was highly zoophagic, and human feeding accounted for only 1.5% of those individuals successfully tested. Cx. gelidus showed bovid feeding at 36% and pig feeding at 12.5%. The test results showed 42.3% Ma. indiana and 12.2% Ma. uniformis had fed on humans. Multiple feeding was observed in Ma. indiana and Ma. uniformis, and most of the double feedings were from bovids and ovids (7.9 and 20.1%, respectively). Pig feeding accounted for 4.8% of the feedings by Cx. tritaeniorhynchus, 5.3% of Ma. indiana, and 6.4% of Ma. uniformis. This study is significant because of the role played by these mosquitoes in the transmission of JEV in the Kuttanadu area of Kerala, India.

  1. Repellent activity of the creams formulated from Annona senegalensis and Boswellia dalzielii leaf fractions and essential oils against Anopheles gambiae (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Lame Younoussa

    2016-12-01

    Full Text Available Objective: To investigate the repellent efficacy of the creams formulated from methanol extract and n-hexane, chloroform, ethyl acetate and methanol fractions as well as essential oils of Annona senegalensis (A. senegalensis and Boswellia dalzielii (B. dalzielii leaves against the malarial vector Anopheles gambiae (An. gambiae in the laboratory. Methods: The efficacies of 25% w/w active ingredient creams formulated from the plant-based products were tested. Different concentrations of the creams, ranging from 2.0 to 12.0 mg/ cm²were applied on the exposed dorsal hand area (25 cm2 of volunteers. The treated hands were submitted to 50 caged blood-starved females of An. gambiae for 3 min after every 30 min until 180 min. Results: Total protection of up to 120 and 60 min without bites of An. gambiae were recorded with n-hexane creams applied at 12 mg/cm2 respectively for A. senegalensis and B. dalzielii. The essential oil creams of the two tested plants applied at 6 mg/cm2 protected volunteers up to 120 min without mosquito bites. The commercial Odomos cream (12% N,N-diethyl- 3-methylbenzamide tested as the positive control at 6 mg/cm2 protected volunteers from mosquito bites up to180 min. Conclusions: These results suggest that the cream formulated from the n-hexane fraction of A. senegalensis and essential oil creams of A. senegalensis and B. dalzielii leaves have the potential of a natural herbal source for the development of new, safe and eco-friendly repellent products to prevent An. gambiae bites.

  2. Consolidating and water repellent treatments applied to wet and salt contaminated granite

    Directory of Open Access Journals (Sweden)

    Silva, B.

    2000-03-01

    Full Text Available A comparison was made of the efficacy of two consolidants and two water repellents applied to samples of granite under optimum conditions, with the efficacy of the same products applied to the granite in the presence of soluble salts or water. The amount of product absorbed and the amount of dry polymer remaining after treatment were compared. The results show that the presence of water and soluble salts in the stone significantly modifies the consumption of the products (in particular the water repellents and also the level of dry polymer retained. The water repellents were found to be much less effective when the substrate contained salts, whereas the presence of water did not appear to influence their efficacy. The lack of correlation between uptake, active dry polymer, and efficacy led to the conclusion that the presence of salts or water markedly changes the kinetics of the polymerization of the products.

    Se analiza la eficacia de dos consolidantes y dos hidrofugantes aplicados a rocas graníticas en condiciones óptimas comparativamente a la eficacia de los mismos productos aplicados sobre los mismos sustratos conteniendo cierta cantidad de sales solubles o de agua. Se compara la cantidad de producto absorbido y la cantidad de materia seca presente tras el curado. Los resultados indican que la presencia de agua y de sales solubles en la piedra modifica significativamente el consumo de los productos, sobre todo el de los hidrofugantes, así como la cantidad de materia seca. Se observa, asimismo, un fuerte detrimento en la eficacia de los hidrofugantes cuando el sustrato contiene sales mientras que, al contrario, la presencia de agua no parece infiuir en dicha eficacia. La falta de correlación entre el consumo, materia seca activa y eficacia lleva a concluir que la presencia de sales o agua modifica sensiblemente la cinética de la polimeración de los productos.

  3. REPELLENCY OF ESSENTIAL OIL OF PIPER ADUNCUM AGAINST AEDES ALBOPICTUS IN THE LABORATORY

    NARCIS (Netherlands)

    Misni, Norashiqin; Sulaiman, Sallehudin; Othman, Hidayatulfathi; Omar, Baharudin

    2009-01-01

    The repellent activity of Piper aduncum essential oil against Aedes albopictus was investigated under laboratory conditions with human volunteers. The lowest median effective dose (ED(50)) value was 1.5 mu g/cm(2) at 60 sec of exposure when compared to 90 see (2.1 mu g/cm(2)) and 120 see (1.8 mu

  4. Seasonal Abundance and Host-Feeding Patterns of Anopheline Vectors in Malaria Endemic Area of Iran

    Directory of Open Access Journals (Sweden)

    Hamidreza Basseri

    2010-01-01

    Full Text Available Seasonal abundance and tendency to feed on humans are important parameters to measure for effective control of malaria vectors. The objective of this study was to describe relation between feeding pattern, abundance, and resting behavior of four malaria vectors in southern Iran. This study was conducted in ten indicator villages (based on malaria incidence and entomological indices in mountainous/hilly and plain regions situated south and southeastern Iran. Mosquito vectors were collected from indoor as well as outdoor shelters and the blood meals were examined by ELISA test. Over all 7654 female Anopheles spp. were captured, the most common species were Anopheles stephensi, An. culicifacies, An. fluviatilis, and An. d'thali. The overall human blood index was 37.50%, 19.83%, 16.4%, and 30.1% for An. fluviatilis, An. stephensi, An. culicifacies, and An. d'thali, respectively. In addition, An. fluviatilis fed on human blood during the entire year but the feeding behavior of An. stephensi and An. culicifacies varied according to seasons. Overall, the abundance of the female mosquito positive to human blood was 4.25% per human shelter versus 17.5% per animal shelter. This result indicates that the vectors had tendency to rest in animal shelters after feeding on human. Therefore, vector control measure should be planned based on such as feeding pattern, abundance, and resting behavior of these vectors in the area.

  5. Freeze dried blood and development of an artificial diet for blood feeding arthropods

    International Nuclear Information System (INIS)

    DeLoach, J.R.; Spates, G.E.; Kapatsa, G.M.; Sheffield, C.L.; Kabayo, J.P.

    1990-01-01

    The goals of the research were to determine the biochemical differences between freeze dried bovine and porcine blood relative to their nutritional value to Glossina palpalis palpalis and Stomoxys calcitrans and to develop an artificial diet for mass rearing these flies. Freeze dried bovine and porcine blood were found to differ in their amino acid content; total dietary lipids did not significantly differ, but some notable exceptions were found in fatty acid content. Both sonication and addition of foetal bovine serum to freeze dried bovine blood improved its nutritional value for G. p. palpalis. A two component, semi-defined artificial diet was developed for G. p. palpalis and S. calcitrans. The College Station diet consisted of lipid contaminated bovine haemoglobin (BHb) and bovine serum albumin (BSA). To conduct dietary deletion tests, a process was developed for preparing large quantities of ultrapure lipid free bovine haemoglobin. S. calcitrans fed on lipid free BHb plus BSA had zero fecundity. Lipids were re-added to the protein diet in three forms: (1) lipid contaminated BHb, (2) pure erythrocyte ghosts, and (3) pure lipids. It was found that membrane lipid from the erythrocyte is required by S. calcitrans. A defined artificial diet consisting of lipid free BHb, BSA, sphingomyelin, phosphatidyl ethanolamine, phosphatidyl serine and cholesterol gave normal adult survival, as well as near normal fecundity and percentage egg hatch for S. calcitrans. Knowing the identity of the lipids, it is now possible to prepare dietary formulations to alleviate dependency on the blood proteins BHb and BSA. (author). 34 refs, 1 fig., 15 tabs

  6. Effect of the Feed Additive Clinoptilolite (ZeoFeed on Nutrient Metabolism and Production Performance of Laying Hens

    Directory of Open Access Journals (Sweden)

    Miroslav Macháček

    2010-01-01

    Full Text Available The aim of this study was to assess the effects of two levels of clinoptilolite administered in feed (2% and 4% on some selected performance indicators, metabolic utilization of basic nutrients and the health status of laying hens. The selected 24 Bovans Goldline hybrid laying hens were divided into three equal groups, two experimental groups (E1 and E2 and one control group (C. The laying hens were housed individually in cages with an automatic supply of drinking water, manual feeding, in a setting with controlled light and temperature regimens. Hens from individual groups were all fed a complete feed mix of the same composition and the only difference was in clinoptilolite supplementation: feed mixes for E1 and E2 groups contained 2% and 4% of clinoptilolite (commercial additive ZeoFeed respectively, replacing the same amounts of wheat. The hens received feed mixes and drinking water ad libitum. During this 28-day experiment, feed consumption and the number and weight of eggs laid were monitored individually for each hen. At the end of the experiment, the balance test using the indicator method (Cr2O3 was performed in all eight hens in each of the groups. The results of balance tests were then used to calculate the metabolic utilization of selected nutrients (nitrogen, fat, ash, nitrogen-free extracts, starch, gross energy, Ca, P. After the balance tests, blood samples for haematological and biochemical examinations were collected via puncture of the vena basilica. The addition of 2% clinoptilolite to feed mix resulted in a highly significant (P ⪬ 0.01 increase in mean egg weight to 64.69 g, but the addition of 4% clinoptilolite in group E2 resulted in a highly significant (P ⪬ 0.01 decrease in mean egg weight to 62.20 g compared to the control (63.73 g. Moreover, daily feed mix consumption in group E1 decreased to 114 g per one laying hen/day compared to the controls (118 g per one laying hen/day. In group E2 (4% clinoptilolite, daily

  7. A dual function for 4-methoxybenzaldehyde in Petasites fragrans? Pollinator-attractant and ant-repellent

    Czech Academy of Sciences Publication Activity Database

    Pattrick, J. G.; Shepherd, T.; Hoppitt, W.; Plowman, Nichola S.; Willmer, P.

    2017-01-01

    Roč. 11, č. 5 (2017), s. 623-627 ISSN 1872-8855 Institutional support: RVO:60077344 Keywords : Petasites fragrans * ant-repellent floral volatiles * 4-methoxybenzaldehyde Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 1.441, year: 2016 https://link.springer.com/article/10.1007/s11829-017-9519-3

  8. Comparative efficacy of IR3535 and deet as repellents against adult Aedes aegypti and Culex quinquefasciatus.

    Science.gov (United States)

    Cilek, J E; Petersen, J L; Hallmon, C E

    2004-09-01

    Arm-in-cage laboratory evaluations of 2 proprietary formulations of the mosquito repellents IR3535 and N,N-diethyl-3-methylbenzamide (deet; aqueous cream, hydroalcoholic spray) were made with 10 and 20% concentrations of each repellent. Also, 4 commercially available products containing IR3535 (Expedition insect repellent 20.07% active ingredient [AI], Bug Guard Plus with SPF30 sunscreen 7.5% AI, Bug Guard Plus with SPF15 sunscreen 7.5% AI, and Bug Guard Plus 7.5% AI) were tested. All comparisons were made on an equal formulation or concentration basis. Eight volunteers tested all formulations or products 3 times against laboratory-reared, Aedes aegypti and Culex quinquefasciatus mosquitoes (6-10 days old). Products were applied to a forearm at the rate of 0.002 g/cm2. The other forearm was not treated and served as a control. Elapsed time to 1st and 2nd consecutive bite was recorded. Mean protection time (i.e., time to 1st bite) with proprietary formulations of IR3535 were comparable to those of deet, with 20% concentrations providing greater protection against Ae. aegypti (3 h) and Cx. quinquefasciatus (6 h). Mean protection time for commercial products containing IR3535 ranged from nearly 90 to 170 min for Ae. aegypti and 3.5 to 6.5 h for Cx. quinquefasciatus. Mean time to the 2nd bite was similar to time to 1st bite for each mosquito species, product, and formulation.

  9. Orthodontic cement with protein-repellent and antibacterial properties and the release of calcium and phosphate ions.

    Science.gov (United States)

    Zhang, Ning; Weir, Michael D; Chen, Chen; Melo, Mary A S; Bai, Yuxing; Xu, Hockin H K

    2016-07-01

    White spot lesions often occur in orthodontic treatments. The objective of this study was to develop a novel resin-modified glass ionomer cement (RMGI) as an orthodontic cement with protein-repellent, antibacterial and remineralization capabilities. Protein-repellent 2-methacryloyloxyethyl phosphorylcholine (MPC), antibacterial dimethylaminohexadecyl methacrylate (DMAHDM), nanoparticles of silver (NAg), and nanoparticles of amorphous calcium phosphate (NACP) were incorporated into a RMGI. Enamel shear bond strength (SBS) was determined. Calcium (Ca) and phosphate (P) ion releases were measured. Protein adsorption onto specimens was determined by a micro bicinchoninic acid method. A dental plaque microcosm biofilm model was tested. Increasing the NACP filler level increased the Ca and P ion release. Decreasing the solution pH increased the ion release. Incorporating MPC into RMGI reduced protein adsorption, which was an order of magnitude less than that of commercial controls. Adding DMAHDM and NAg into RMGI yielded a strong antibacterial function, greatly reducing biofilm viability and acid production. Biofilm CFU counts on the multifunctional orthodontic cement were 3 orders of magnitude less than that of commercial control (p0.1). A novel multifunctional orthodontic cement was developed with strong antibacterial and protein-repellent capabilities for preventing enamel demineralization. The new cement is promising to prevent white spot lesions in orthodontic treatments. The method of incorporating four bioactive agents may have wide applicability to the development of other bioactive dental materials to inhibit caries. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Effects of lactoferrin feeding on growth, feed intake and health of calves.

    Science.gov (United States)

    Prenner, Maria L; Prgomet, Christian; Sauerwein, Helga; Pfaffl, Michael W; Broz, Jiri; Schwarz, Frieder J

    2007-02-01

    Lactoferrin (LF) exhibits a broad spectrum of anti-microbial properties and may have regulatory functions in the immune system. In the present study, 40 calves (20 males, 20 females) were used to examine the effects of supplemental bovine LF added to colostrum and milk replacer (at 0.16%) on health, weight development and feed intake during a 70-day experimental period. The calves were allocated to a treatment group (n = 20) and a control group (n = 20); the groups were balanced in terms of sex, live weight and date of birth. Body weight and feed intake were measured at regular intervals. Blood and colostrum samples were collected to determine the content of IgG. In addition, colostrum and milk replacer samples were analysed for their LF concentrations. Significantly higher IgG values were observed in the LF treated than in the control group during the entire feeding experiment from week 2 to week 6. Calves receiving LF had less days of disease with less serious cases of diarrhoea than the control group. Body weight and feed intake were not significantly different between the treatments; in male calves LF-treated animals tended towards higher weight gains. This study indicates that LF is advantageous for health and may therefore be a beneficial supplement in the diets for neonatal calves.

  11. Effect of radiation-treated feeds on some biochemical indicators of nutrition level achieved with energy nutrients

    International Nuclear Information System (INIS)

    Smid, K.; Dvorak, J.; Hrusovsky, J.

    1985-01-01

    Two groups of dogs were fed for 90 days a diet irradiated with 60 Co to a dose of 25 kGy/kg. Two other groups of experimental animals were fed over the same period a nonirradiated diet. Laboratory examinations of the irradiated feeds showed their microbiological and mycological intactness. Irradiation caused a significant 35% degradation of essential amino acids and an increase in ammoniacal nitrogen, destruction changes in the lipid component of the feeds and partial decomposition of the saccharide component. Organoleptic examination of the irradiated feeds did not show any perceptible changes. Hematological examination of the animals fed the irradiated feeds showed significant negative effects on the blood count. Biochemical examination of the blood serum and plasma showed that the total protein of the experimental dogs dropped and that the creatinine level had also significantly decreased. The increase in free ammonia caused by ionizing radiation increased the pH level in the dogs' blood. The destruction of the lipid fraction in the feeds caused a decrease in the activity of lipofilic axerophthol thereby distrubing the biological value of the feeds. There was a significant decrease in the magnesium level in animals fed the irradiated feeds without biological supplements. On the other hand, the levels of potassium, calcium and phosphorus did not reflect the difference between the two groups of animals. (author)

  12. Design of water-repellant coating using dual scale size of hybrid silica nanoparticles on polymer surface

    Science.gov (United States)

    Conti, J.; De Coninck, J.; Ghazzal, M. N.

    2018-04-01

    The dual-scale size of the silica nanoparticles is commonly aimed at producing dual-scale roughness, also called hierarchical roughness (Lotus effect). In this study, we describe a method to build a stable water-repellant coating with controlled roughness. Hybrid silica nanoparticles are self-assembled over a polymeric surface by alternating consecutive layers. Each one uses homogenously distributed silica nanoparticles of a particular size. The effect of the nanoparticle size of the first layer on the final roughness of the coating is studied. The first layer enables to adjust the distance between the silica nanoparticles of the upper layer, leading to a tuneable and controlled final roughness. An optimal size nanoparticle has been found for higher water-repellency. Furthermore, the stability of the coating on polymeric surface (Polycarbonate substrate) is ensured by photopolymerization of hybridized silica nanoparticles using Vinyl functional groups.

  13. Altered behavioral responses of Sindbis virus-infected Aedes aegypti (Diptera: Culicidae) to DEET and non-DEET based insect repellents.

    Science.gov (United States)

    Qualls, Whitney A; Day, Jonathan F; Xue, Rui-de; Bowers, Doria F

    2012-06-01

    Changes in the time to first bite (TFB) and the bloodfeeding behavior of adult female Aedes aegypti (L.) mosquitoes following dissemination of Sindbis virus (SINV) were observed after exposure to repellents with the active ingredients (AI) DEET, picaridin, 2-undecanone (2-U), and oil of lemon eucalyptus. Dissemination of SINV significantly decreased (Ptimes were observed in SINV infected mosquitoes after exposure to the four repellents compared to uninfected mosquitoes. Taken together, a decrease in TFB and time to complete the four bloodfeeding stages will lessen the prey-status, and enhance both the chances of mosquito survival and arbovirus transmission. Published by Elsevier B.V.

  14. Multiple blood meals in Anopheles darlingi (Diptera: Culicidae).

    Science.gov (United States)

    de Oliveira, Caroline Dantas; Tadei, Wanderli Pedro; Abdalla, Fábio Camargo; Paolucci Pimenta, Paulo Filemon; Marinotti, Osvaldo

    2012-12-01

    Anopheles darlingi is an important vector of human malaria in the Amazon. Adult females of this mosquito species require a blood meal to develop eggs, preferring humans to other blood sources. Although gonotrophic concordance has been described as the norm for An. darlingi, here we report An. darlingi female mosquitoes taking two or more blood meals within their first gonotrophic cycle. Only half of field-captured adult females fed one blood meal developed follicles to Christophers' stage V. This outcome is dependent on larval nutrition, as 88% of laboratory-raised well-nourished females completed the first gonotrophic cycle with only one blood meal, while less nourished females needed additional blood meals. Half of the field-captured blood-seeking An. darlingi females had follicles in intermediate (IIIa and IIIb) and final (V) stages of the gonotrophic cycle, supporting the conclusion that An. darlingi blood feed more than once during a gonotrophic cycle. Additionally, we observed females attempting to blood feed a second time during the same day. Additional studies of An. darlingi biting behavior are necessary to accurately estimate Plasmodium sp. entomologic inoculation rates throughout the An. darlingi vast geographical distribution. © 2012 The Society for Vector Ecology.

  15. Physicians, Primary Caregivers and Topical Repellent: All Under-Utilised Resources in Stopping Dengue Virus Transmission in Affected Households.

    Directory of Open Access Journals (Sweden)

    Nguyet Minh Nguyen

    2016-05-01

    Full Text Available Primary health care facilities frequently manage dengue cases on an ambulatory basis for the duration of the patient's illness. There is a great opportunity for specific messaging, aimed to reduce dengue virus (DENV transmission in and around the home, to be directly targeted toward this high-risk ambulatory patient group, as part of an integrated approach to dengue management. The extent however, to which physicians understand, and can themselves effectively communicate strategies to stop focal DENV transmission around an ambulatory dengue case is unknown; the matter of patient comprehension and recollection then ensues. In addition, the effectiveness of N,N-diethyl-3-methylbenzamide (DEET-based insect repellent in protecting dengue patients from Aedes aegypti mosquitoes' bites has not been investigated.A knowledge, attitude and practice (KAP survey, focusing on the mechanisms of DENV transmission and prevention, was performed using semi-structured questionnaires. This survey was targeted towards the patients and family members providing supportive care, and physicians routinely involved in dengue patient management in Southern Vietnam. An additional clinical observational study was conducted to measure the efficacy of a widely-used 13% DEET-based insect repellent to repel Ae. aegypti mosquitoes from the forearms of dengue cases and matched healthy controls.Among both the physician (n = 50 and patient (n = 49 groups there were several respondents lacking a coherent understanding of DENV transmission, leading to some inappropriate attitudes and inadequate acute preventive practices in the household. The application of insect repellent to protect patients and their relatives from mosquito bites was frequently recommended by majority of physicians (78% participating in the survey. Nevertheless, our tested topical application of 13% DEET conferred only ~1hr median protection time from Ae. aegypti landing. This is notably shorter than that

  16. AN INVESTIGATION OF INSECT OVIPOSITING REPELLENT ACTIVITY OF ANDROGRAPHIS PANICULATA NESS, ACACIA AURICULIFORMIS AND PIPER BETLE LINN LEAVES EXTRACTS TO BATROCERA CARAMBOLAE

    Directory of Open Access Journals (Sweden)

    Nurcahyo Iman Prakoso

    2017-12-01

    Full Text Available Batrocera carambolae was one of the main pests in some types of fruits. This pest attack resulted in quantitative damage in the form of fall of young fruit and qualitatively in the form of fruit to rot and contains maggots. This research was conducted to determine selected extract from Andrographis Paniculata Ness, Piper betle Linn and Acacia auriculiformis leaves which have repellent activity for Batrocera carambolae. Nine extracts from the maceration process of the three leaves were evaluated by placing the extracts and flies together in the cage. The ethanol, ethyl acetate, and n-hexane extracts from Andrographis Paniculata Ness, Piper betle Linn and Acacia auriculiformis leaves were applied to the test pieces and fed into a cage containing 10 male and female flies. From observation, N-hexane extracts from Andrographis Paniculata Ness and Piper betle Linn leaves and ethyl acetate extracts from Acacia auriculiformis leaf having good activity as repellent and potentially to be used as a insect ovipositing repellent of Batrocera carambolae.

  17. Fluorescent probes for understanding soil water repellency: the novel application of a chemist's tool to soil science

    Science.gov (United States)

    Balshaw, Helen M.; Davies, Matthew L.; Doerr, Stefan H.; Douglas, Peter

    2015-04-01

    Food security and production is one of the key global issues faced by society. It has become essential to work the land efficiently, through better soil management and agronomy whilst protecting the environment from air and water pollution. The failure of soil to absorb water - soil water repellency can lead to major environmental problems such as increased overland flow and soil erosion, poor uptake of agricultural chemicals, and increased risk of groundwater pollution due to the rapid transfer of contaminants and nutrient leaching through uneven wetting and preferential flow pathways. Understanding the causes of soil hydrophobicity is essential for the development of effective methods for its amelioration, supporting environmental stability and food security. Organic compounds deposited on soil mineral or aggregate surfaces have long been recognised as a major factor in causing soil water repellency. It is widely accepted that the main groups of compounds responsible are long-chain acids, alkanes and other organic compounds with hydrophobic properties. However, when reapplied to sands and soils, the degree of water repellency induced by these compounds and mixtures varied widely with compound type, amount, and mixture, in a seemingly unpredictable way. Fluorescent and phosphorescent probes are widely used in chemistry and biochemistry due to their sensitive response to their physical and chemical environment, such as polarity, and viscosity. However, they have to-date not been used to study soil water repellency. Here we present preliminary work on the evaluation of fluorescent probes as tools to study two poorly understood features that determine the degree of wettability for water repellent soils: (i) the distribution of organics on soils; (ii) the changes in polarity at soil surfaces required for water drops to infiltrate. In our initial work we have examined probes adsorbed onto model soils, prepared by adsorption of specific organics onto acid washed sand

  18. The effects of feeding time on milk production, total-tract digestibility, and daily rhythms of feeding behavior and plasma metabolites and hormones in dairy cows.

    Science.gov (United States)

    Niu, M; Ying, Y; Bartell, P A; Harvatine, K J

    2014-12-01

    The timing of feed intake entrains circadian rhythms regulated by internal clocks in many mammals. The objective of this study was to determine if the timing of feeding entrains daily rhythms in dairy cows. Nine Holstein cows were used in a replicated 3 × 3 Latin square design with 14-d periods. An automated system recorded the timing of feed intake over the last 7 d of each period. Treatments were feeding 1×/d at 0830 h (AM) or 2030 h (PM) and feeding 2×/d in equal amounts at 0830 and 2030 h. All treatments were fed at 110% of daily intake. Cows were milked 2×/d at 0500 and 1700 h. Milk yield and composition were not changed by treatment. Daily intake did not differ, but twice-daily feeding tended to decrease total-tract digestibility of organic matter and neutral detergent fiber (NDF). A treatment by time of day interaction was observed for feeding behavior. The amount of feed consumed in the first 2h after feeding was 70% greater for PM compared with AM feeding. A low rate of intake overnight (2400 to 0500 h; 2.2 ± 0.74% daily intake/h, mean ± SD) and a moderate rate of intake in the afternoon (1200 to 1700 h; 4.8 ± 1.1% daily intake/h) was noted for all treatments, although PM slightly reduced the rate during the afternoon period compared with AM. A treatment by time of day interaction was seen for fecal NDF and indigestible NDF (iNDF) concentration, blood urea nitrogen, plasma glucose and insulin concentrations, body temperature, and lying behavior. Specifically, insulin increased and glucose decreased more after evening feeding than after morning feeding. A cosine function within a 24-h period was used to characterize daily rhythms using a random regression. Rate of feed intake during spontaneous feeding, fecal NDF and iNDF concentration, plasma glucose, insulin, NEFA, body temperature, and lying behavior fit a cosine function within a 24-h period that was modified by treatment. In conclusion, feeding time can reset the daily rhythms of feeding and

  19. Impacts of grass removal on wetting and actual water repellency in a sandy soil

    NARCIS (Netherlands)

    Oostindie, K.; Dekker, L.W.; Wesseling, J.G.; Geissen, V.; Ritsema, C.J.

    2016-01-01

    Soil water content and actual water repellency were assessed for soil profiles at two sites in a bare and grasscovered plot of a sand pasture, to investigate the impact of the grass removal on both properties. The soil of the plots was sampled six times in vertical transects to a depth of 33 cm

  20. Repellency of essential oil of Piper aduncum against Aedes albopictus in the laboratory.

    Science.gov (United States)

    Misni, Norashiqin; Sulaiman, Sallehudin; Othman, Hidayatulfathi; Omar, Baharudin

    2009-12-01

    The repellent activity of Piper aduncum essential oil against Aedes albopictus was investigated under laboratory conditions with human volunteers. The lowest median effective dose (ED50) value was 1.5 microg/cm2 at 60 sec of exposure when compared to 90 sec (2.1 microg/cm2) and 120 sec (1.8 microg/cm2) of exposure. At 0.4 g, the essential oil gave a high protection (95.2%) against Ae. albopictus bites or landing at 2 h postapplication. The percentage of protection was reduced to 83.3% after 4 h, 64.5% after 6 h, and 51.6% after 8 h postapplication. As a comparison, treatment with 10% deet gave 100% protection against mosquito biting/landing for 4 h postapplication. There was no significant difference in percentage protection reduction between the plant extract and the commercial product deet, respectively (P = 0.739). The essential oil, which was not as good as deet, still gave moderate protection against Ae. albopictus biting even until 4 h postapplication. In conclusion, the P. aduncum essential oil has the potential to be used as a repellent against the dengue/dengue hemorrhagic fever vector, Ae. albopictus.

  1. Repellent Activity of Botanical Oils against Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae

    Directory of Open Access Journals (Sweden)

    Emily H. Kuhns

    2016-07-01

    Full Text Available The Asian citrus psyllid, Diaphorina citri Kuwayama, is the insect vector of the pathogen causing huanglongbing. We selected three botanical oils to evaluate behavioral activity against D. citri. In laboratory olfactometer assays, fir oil was repellent to D. citri females, while litsea and citronella oils elicited no response from D. citri females. In choice settling experiments, D. citri settled almost completely on control plants rather than on plants treated with fir oil at a 9.5 mg/day release rate. Therefore, we conducted field trials to determine if fir oil reduced D. citri densities in citrus groves. We found no repellency of D. citri from sweet orange resets that were treated with fir oil dispensers releasing 10.4 g/day/tree as compared with control plots. However, we found a two-week decrease in populations of D. citri as compared with controls when the deployment rate of these dispensers was doubled. Our results suggest that treatment of citrus with fir oil may have limited activity as a stand-alone management tool for D. citri and would require integration with other management practices.

  2. Positive effects of acarbose in the diabetic rat are not altered by feeding schedule.

    Science.gov (United States)

    Wright, B E; Vasselli, J R; Katovich, M J

    1998-03-01

    We previously demonstrated that chronic dietary treatment with acarbose, an alpha-glucosidase inhibitor, improves glucose homeostasis in the streptozotocin (STZ)-induced diabetic rat. In this study we evaluated the effects of 4 weeks of acarbose treatment on glucose homeostasis in STZ-diabetic rats for both meal-fed (three times daily) and ad libitum feeding conditions. Sprague Dawley male rats (n = 58) were started on a daily meal-feeding paradigm consisting of three 2-h feeding periods: 0700 to 0900 hours, 1300 to 1500 hours, and 1900 to 2100 hours. Following 2 weeks of adaptation, half of the animals were switched to ad libitum feeding. The feeding paradigm itself (meal fed versus ad lib.) affected neither body weight nor daily food intake. Twenty animals from each feeding group then received STZ (60 mg/kg i.v.), whereas control animals received vehicle injections only. Two days later, the diet of 10 STZ-treated animals from each paradigm was supplemented with acarbose (40 mg of BAY G 5421/100-g diet), and the groups were treated for 4 weeks. Untreated diabetic rats had lower body weight than vehicle-injected control rats at all time points after STZ treatment. Acarbose treatment delayed this effect on body weight. STZ treatment induced hyperphagia regardless of feeding paradigm, which was significantly attenuated by acarbose only for the first week of treatment. Untreated diabetic rats had fasting blood glucose values 4 times those of vehicle-injected controls in both the meal-fed and ad libitum-fed conditions. Acarbose significantly lowered fasting blood glucose in the treated STZ groups. Blood glucose was also assessed 0, 90, and 180 min following the start of a meal. The postprandial rise in blood glucose was significantly reduced in acarbose-treated meal-fed diabetic rats, to values not significantly different from those of vehicle-injected control rats. During the fourth week of treatment glycated hemoglobin levels were significantly higher in untreated

  3. Simulated Seasonal Photoperiods and Fluctuating Temperatures Have Limited Effects on Blood Feeding and Life History in Aedes triseriatus (Diptera: Culicidae).

    Science.gov (United States)

    Westby, K M; Juliano, S A

    2015-09-01

    Biotic and abiotic factors change seasonally and impact life history in temperate-zone ectotherms. Temperature and photoperiod are factors that change in predictable ways. Most studies testing for effects of temperature on vectors use constant temperatures and ignore potential correlated effects of photoperiod. In two experiments, we tested for effects of larval rearing environments creating ecologically relevant temperatures and photoperiods simulating early and late season conditions (June and August), or constant temperatures (cool and warm) with the June or August photoperiods, respectively. We determined effects on survivorship, development, size, and a composite performance index in a temperate-zone population of Aedes triseriatus (Say). We followed cohorts of resulting females, all held under the same environmental conditions, to assess carry-over effects of rearing conditions for larvae on longevity, blood feeding, and egg production. Larval survivorship was affected by treatment in one experiment. Development time was greater in the June and cool treatments, but the constant and fluctuating temperatures did not differ. Significantly larger mosquitoes were produced in fluctuating versus constant temperature treatments. There were no significant treatment effects on the composite performance index. Adult female longevity was lower after rearing at constant versus fluctuating temperature, but there was no difference between June and August, nor did size affect longevity. There was no effect of treatments on blood feeding and a limited effect on egg production. We conclude that seasonal temperatures and photoperiods during development have limited effects on this population of A. triseriatus and find little evidence of strong effects of fluctuating versus constant temperatures. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Transfer of blood urea nitrogen to cecal microbial nitrogen is increased by fructo-oligosaccharide feeding in guinea pigs.

    Science.gov (United States)

    Kawasaki, Kiyonori; Min, Xiao; Li, Xiao; Hasegawa, Ena; Sakaguchi, Ei

    2015-01-01

    The present study was conducted to determine the mechanism by which nitrogen (N) availability is improved by fructo-oligosaccharide (FOS) in guinea pigs. Adult male guinea pigs were fed a commercial pellet diet (50 g/day) with either 5% glucose or 5% FOS for 7 days in individual metabolism cages. After 7 days of feeding the diet, (15) N-urea was administered intravenously 1 h before slaughter under anesthesia. The amount and concentration of total, protein, bacterial, ammonia and urea N and the (15) N atom % excess were measured in blood, liver, gut contents and urine. The (15) N atom % excess of total and protein N, and the amount of total, protein and bacteria N and (15) N in the cecum were significantly increased by the consumption of FOS. Furthermore, the concentration and amount of short-chain fatty acids were significantly increased by the consumption of FOS. In contrast, the amount of urinary (15) N was significantly decreased by the consumption of FOS. These results suggest that consumption of FOS increases transfer of blood urea N into the large intestine for bacterial N synthesis, which is subsequently re-absorbed by cecotrophy, and contributes to the increase of N utilization in guinea pigs. © 2014 Japanese Society of Animal Science.

  5. Field measurement of soil water repellency and its impact on water flow under different vegetation

    Czech Academy of Sciences Publication Activity Database

    Lichner, Ľ.; Hallett, P. D.; Feeney, D. S.; Ďugová, O.; Šír, Miloslav; Tesař, Miroslav

    2007-01-01

    Roč. 62, č. 5 (2007), s. 537-541 ISSN 0006-3088 R&D Projects: GA ČR GA205/05/2312 Institutional research plan: CEZ:AV0Z20600510 Keywords : vegetation * sandy soil * water repellency * hydraulic conductivity Subject RIV: DA - Hydrology ; Limnology Impact factor: 0.207, year: 2007

  6. Factors influencing the use of topical repellents: implications for the effectiveness of malaria elimination strategies

    NARCIS (Netherlands)

    Gryseels, C.; Uk, S.; Sluydts, V.; Durnez, L.; Phoeuk, P.; Suon, S.; Set, S.; Heng, S.; Siv, S.; Gerrets, R.; Tho, S.; Coosemans, M.; Peeters Grietens, K.

    2015-01-01

    In Cambodia, despite an impressive decline in prevalence over the last 10 years, malaria is still a public health problem in some parts of the country. This is partly due to vectors that bite early and outdoors reducing the effectiveness of measures such as Long-Lasting Insecticidal Nets. Repellents

  7. Effects of the botanical compound p-anisaldehyde on horn fly, Haematobia irritans irritans (L.) (Diptera: Muscidae) repellency, mortality, and reproduction

    Science.gov (United States)

    The horn fly, Haematobia irritans irritans (L.), is an economically important obligate blood-feeding ectoparasite that mainly attacks cattle worldwide. As resistance to conventional insecticides increases, alternative control tactics are being investigated. p-Anisaldehyde occurs in many plants and i...

  8. Enhanced repellency of binary mixtures of Zanthoxylum armatum seed oil, vanillin, and their aerosols to mosquitoes under laboratory and field conditions.

    Science.gov (United States)

    Kwon, Hyung Wook; Kim, Soon-Il; Chang, Kyu-Sik; Clark, J Marshall; Ahn, Young-Joon

    2011-01-01

    The repellency of Zanthoxylum armatum seed oil (ZA-SO), alone or in combination with vanillin (VA), its six major constituents, and another four major previously known Zanthoxylum piperitum fruit oil constituents, as well as aerosol products containing 5 or 10% ZA-SO and 5% VA, was evaluated against female Aedes aegypti in laboratory and field studies. Results were then compared with those of N,N-diethyl-3-methylbenzamide (DEET) as a standard. Hand in cage laboratory tests showed that 0.2, 0.1, and 0.05 mg/cm2 ZA-SO resulted in > 92% protection through 30-min postexposure and was not significantly different than 0.05 mg/cm2 DEET. Skin treated with linalool and limonene (from Z. armatum) provided > 80% repellency to female Ae. aegypti at 10-min exposure, whereas cuminaldehyde, citronellal, geranyl acetate, and cuminyl alcohol (from Zanthoxylum piperitum) provided > 90% protection during this same time period. Only cuminaldehyde and citronellal provided complete protection comparable to DEET at 10-min postexposure. After that time, repellency of all plant constituents to mosquitoes was considerably decreased (biting and nuisance caused by mosquitoes.

  9. Repelência e deterrência na oviposição de Bemisia tabaci biótipo B pelo uso de extratos vegetais em Cucurbita pepo L Repellence and deterrence on oviposition of Bemisia tabaci biotype B by the use of vegetal extracts in Cucurbita pepo L

    Directory of Open Access Journals (Sweden)

    J.P.G.F. Silva

    2012-01-01

    Full Text Available Bemisia tabaci biótipo B é um dos principais insetos-praga na cultura da abobrinha (Cucurbita pepo L.. O manejo dessa mosca-branca tornou-se grande desafio aos agricultores, uma vez que esta apresenta rápida capacidade de desenvolver resistência a diferentes classes de inseticidas. Como alternativa vem sendo investigado o uso de extratos vegetais com atividades inseticida e/ou insetistática, os quais têm revelado resultados promissores no combate a inseto. O presente trabalho teve por objetivo avaliar os possíveis efeitos de sete extratos provenientes de cinco espécies vegetais, Ruta graveolens L. (folhas, Azadirachta indica A. Juss. (folhas + ramos, Trichilia pallida Swartz (ramos, T. pallida (folhas, A. indica (amêndoas, Chenopodium ambrosioides L. (inflorescências + ramos+ folhas e Mentha pulegium L. (folhas, sobre Bemisia tabaci biótipo B em abobrinha, por meio de testes de repelência e deterrência para oviposição. Em teste com chance de escolha, avaliou-se a atratividade e determinou-se o índice de repelência após 6, 24 e 48 horas da aplicação dos extratos. A oviposição foi verificada após a terceira contagem do número de adultos. O extrato à base de folhas de M. pulegium mostrou repelência e deterrência à oviposição de B. tabaci biótipo B, podendo ser recomendado como alternativa para o manejo do inseto.Bemisia tabaci biotype B is one of the main pests in squash (Cucurbita pepo L.. The management of this whitefly has become a major challenge to growers, since they have the ability to quickly develop resistance to different classes of insecticides. Alternatively, the use of plant extracts with insecticide and/or insectistatic activities has been investigated, showing promising results for the whitefly control. The present study evaluated the possible effects of seven extracts from five plant species, Ruta graveolens L. (leaves, Azadirachta indica A. Juss. (leaves + branches, Trichilia pallida Swartz (branches

  10. Efficacy of Advanced Odomos repellent cream (N, N-diethyl-benzamide) against mosquito vectors.

    Science.gov (United States)

    Mittal, P K; Sreehari, U; Razdan, R K; Dash, A P; Ansari, M A

    2011-04-01

    Repellents are commonly used personal protection measures to avoid mosquito bites. In the present study, Advanced Odomos cream (12% N, N-diethyl-benzamide) was tested for its efficacy against mosquitoes in comparison to DEET (N,N-diethyl-3-methyl benzamide). Bioassays were conducted to assess the repellency of Advanced Odomos and DEET creams against Anopheles stephensi and Aedes aegypti. Their efficacy was tested on human volunteers applied with different concentrations of test creams ranging from 1 to 12 mg/cm 2 and by exposing them to mosquitoes at hourly intervals. Field evaluation was also carried out to test the duration of protection of the test creams against Anopheles and Aedes mosquitoes during whole night and day time collections, respectively on human volunteers. Mosquito collections were done using torch light and aspirator. Complete (100%) protection was achieved at 10 mg/cm 2 cream formulation of Advanced Odomos (1.2 mg a.i/cm 2 ) dose against An. stephensi and 12 mg/cm 2 (1.44 mg a.i./cm 2 ) against Ae. aegypti on human baits. There was no statistically significant differences in per cent protection against mosquito bites between Advanced Odomos and DEET cream (P>0.05) in respective doses. Complete protection up to 11 h was observed against Anopheles mosquitoes during whole night collections and up to 6 h against Ae. aegypti in day time collections. No adverse reactions such as itching, irritation, vomiting, nausea, etc. were reported by the volunteers. Advanced Odomos cream applied at 10 mg/cm 2 concentration provided 100% protection from Anopheles mosquitoes up to 11 h whereas about 6 h protection was recorded against Ae. aegypti. The laboratory and field trials indicate that for longer protection against Anopheles mosquitoes 10 mg/cm 2 will be appropriate and in case of Ae. aegypti more than 10 mg/cm 2 application is required for complete protection. In conclusion, the Advanced Odomos cream was comparable to the known repellent cream DEET for

  11. Fire impact on soil-water repellency and functioning of semi-arid croplands and rangelands: Implications for prescribed burnings and wildfires

    Science.gov (United States)

    Stavi, Ilan; Barkai, Daniel; Knoll, Yaakov M.; Glion, Hiam Abu; Katra, Itzhak; Brook, Anna; Zaady, Eli

    2017-03-01

    An unintended fire outbreak during summer 2015 in the semi-arid Israeli Negev resulted in the burning of extensive croplands and rangelands. The rangelands have been managed over the long term for occasional grazing, while the croplands have been utilized for rainfed wheat cropping. Yet, during the studied year, the croplands were left fallow, allowing the growth of herbaceous vegetation, which was harvested and baled for hay before the fire outbreak. The study objectives were to investigate the impacts of fire, land-use, and soil depth on water-repellency and on the status and dynamics of some of the most important organic and mineral soil resources. Additionally, we aimed to assess the severity of this fire outbreak. The soil-water repellency was studied by measuring the soil's water drop penetration time (WDPT) and critical surface tension (CST). A significant effect of fire on soil hydrophobicity was recorded, with a slight increase in mean WDPT and a slight decrease in mean CST in the burnt sites than in the non-burnt sites. Yet, soil hydrophobicity in the burnt lands was rather moderate and remained within the water repellency's lowest class. A significant effect of land-use on the means of WDPT and CST was also recorded, being eleven-fold greater and 7% smaller, respectively, in the rangelands than in the croplands. This is consistent with the almost eightfold greater mean above-ground biomass recorded in the non-burnt rangelands than in the non-burnt post-harvest croplands, revealing the positive relations between available fuel load and soil-water repellency. The effect of soil depth was significant for CST but not for WDPT. Overall, the gathered data suggest that fire severity was low to moderate. Fire was also found to significantly affect the fire severity only slightly increased the soil water repellency, and at the same time, increased on-site availability of some important soil resources. Nevertheless, it is acknowledged that such fires could impose

  12. Nutrient utilisation and methane emissions in Sahiwal calves differing in residual feed intake.

    Science.gov (United States)

    Sharma, Vimlesh C; Mahesh, Munnurpal S; Mohini, Madhu; Datt, Chander; Nampoothiri, Vinu M

    2014-01-01

    The presented study aimed at investigating the residual feed intake (RFI) of Sahiwal calves, nutrient utilisation as affected by RFI and its relationship with methane (CH4) emissions and some blood metabolites. Eighteen male Sahiwal calves (10-18 months of age; mean body weight 133 kg) were fed ad libitum with a total mixed ration. After calculating RFI for individual calves (-0.40 to +0.34 kg DM/d), they were divided into three groups with low, medium and high RFI, respectively. Dry matter intake (DMI) was higher (p feed conversion ratio were similar among the groups. With exception of glucose, concentrations of all measured blood metabolites were higher in Group High RFI (p feed efficiency and less CH4 production were observed in Group Low RFI, it was concluded that RFI can be used as a measure of feed efficiency, which has a potential to select Sahiwal calves for lowered CH4 emissions.

  13. Biomimetic approaches for green tribology: from the lotus effect to blood flow control

    International Nuclear Information System (INIS)

    Maani, Nazanin; Rayz, Vitaliy S; Nosonovsky, Michael

    2015-01-01

    The research in Green tribology combines several areas including biomimetic tribomaterials and surfaces for controlled adhesion. Biomimetic surfaces mimic living nature and thus they are eco-friendly. The most famous biomimetic surface effect is the Lotus effect (reduction of water adhesion to a solid surface due to micro/nanostructuring of the solid surface). Several extensions of the Lotus effect have been discussed in the literature including the oleophobicity (repelling organic liquids such as oils), underwater oleophobicity to reduce fouling, and the shark skin effect (flow drag reduction due to specially oriented micro-riblets). Here we suggest a potentially important application of micro/nanostructured surfaces in the biomedical area: the micro/nanostructure controlled adhesion in blood flow. Blood is a suspension, and its adhesion properties are different from those of water and oil. For many cardiovascular applications, it is desirable to reduce stagnation and clotting of blood. Therefore, both the underwater oleophobicuity and shark-skin effect can be used. We discuss how computational fluid dynamics models can be used to investigate the structure–property relationships of surface pattern-controlled blood flow adhesion. (paper)

  14. Acute effects of feeding fructose, glucose and sucrose on blood lipid levels and systemic inflammation.

    Science.gov (United States)

    Jameel, Faizan; Phang, Melinda; Wood, Lisa G; Garg, Manohar L

    2014-12-16

    Recent studies have demonstrated a relationship between fructose consumption and risk of developing metabolic syndrome. Mechanisms by which dietary fructose mediates metabolic changes are poorly understood. This study compared the effects of fructose, glucose and sucrose consumption on post-postprandial lipemia and low grade inflammation measured as hs-CRP. This was a randomized, single blinded, cross-over trial involving healthy subjects (n=14). After an overnight fast, participants were given one of 3 different isocaloric drinks, containing 50 g of either fructose or glucose or sucrose dissolved in water. Blood samples were collected at baseline, 30, 60 and 120 minutes post intervention for the analysis of blood lipids, glucose, insulin and high sensitivity C-reactive protein (hs-CRP). Glucose and sucrose supplementation initially resulted in a significant increase in glucose and insulin levels compared to fructose supplementation and returned to near baseline values within 2 hours. Change in plasma cholesterol, LDL and HDL-cholesterol (measured as area under curve, AUC) was significantly higher when participants consumed fructose compared with glucose or sucrose (PAUC for plasma triglyceride levels however remained unchanged regardless of the dietary intervention. Change in AUC for hs-CRP was also significantly higher in subjects consuming fructose compared with those consuming glucose (P<0.05), but not sucrose (P=0.07). This study demonstrates that fructose as a sole source of energy modulates plasma lipids and hsCRP levels in healthy individuals. The significance of increase in HDL-cholesterol with a concurrent increase in LDL-cholesterol and elevated hs-CRP levels remains to be delineated when considering health effects of feeding fructose-rich diets. ACTRN12614000431628.

  15. Linking hydraulic properties of fire-affected soils to infiltration and water repellency

    Science.gov (United States)

    Moody, John A.; Kinner, David A.; Úbeda, Xavier

    2009-12-01

    SummaryHeat from wildfires can produce a two-layer system composed of extremely dry soil covered by a layer of ash, which when subjected to rainfall, may produce extreme floods. To understand the soil physics controlling runoff for these initial conditions, we used a small, portable disk infiltrometer to measure two hydraulic properties: (1) near-saturated hydraulic conductivity, K f and (2) sorptivity, S( θ i), as a function of initial soil moisture content, θ i, ranging from extremely dry conditions ( θ i ash, reference soils, soils unaffected by fire, and fire-affected soils. Each has a different degrees of water repellency that influences K f and S( θ i). Values of K f ranged from 4.5 × 10 -3 to 53 × 10 -3 cm s -1 for ash; from 0.93 × 10 -3 to 130 × 10 -3 cm s -1 for reference soils; and from 0.86 × 10 -3 to 3.0 × 10 -3 cm s -1, for soil unaffected by fire, which had the lowest values of K f. Measurements indicated that S( θ i) could be represented by an empirical non-linear function of θ i with a sorptivity maximum of 0.18-0.20 cm s -0.5, between 0.03 and 0.08 cm 3 cm -3. This functional form differs from the monotonically decreasing non-linear functions often used to represent S( θ i) for rainfall-runoff modeling. The sorptivity maximum may represent the combined effects of gravity, capillarity, and adsorption in a transitional domain corresponding to extremely dry soil, and moreover, it may explain the observed non-linear behavior, and the critical soil-moisture threshold of water repellent soils. Laboratory measurements of K f and S( θ i) are the first for ash and fire-affected soil, but additional measurements are needed of these hydraulic properties for in situ fire-affected soils. They provide insight into water repellency behavior and infiltration under extremely dry conditions. Most importantly, they indicate how existing rainfall-runoff models can be modified to accommodate a possible two-layer system in extremely dry conditions. These

  16. Blood feeding by the Rocky Mountain spotted fever vector, Dermacentor andersoni, induces interleukin-4 expression by cognate antigen responding CD4+ T cells

    Directory of Open Access Journals (Sweden)

    Wikel Stephen K

    2009-10-01

    Full Text Available Abstract Background Tick modulation of host defenses facilitates both blood feeding and pathogen transmission. Several tick species deviate host T cell responses toward a Th2 cytokine profile. The majority of studies of modulation of T cell cytokine expression by ticks were performed with lymphocytes from infested mice stimulated in vitro with polyclonal T cell activators. Those reports did not examine tick modulation of antigen specific responses. We report use of a transgenic T cell receptor (TCR adoptive transfer model reactive with influenza hemagglutinin peptide (110-120 to examine CD4+ T cell intracellular cytokine responses during infestation with the metastriate tick, Dermacentor andersoni, or exposure to salivary gland extracts. Results Infestation with pathogen-free D. andersoni nymphs or administration of an intradermal injection of female or male tick salivary gland extract induced significant increases of IL-4 transcripts in skin and draining lymph nodes of BALB/c mice as measured by quantitative real-time RT-PCR. Furthermore, IL-10 transcripts were significantly increased in skin while IL-2 and IFN-γ transcripts were not significantly changed by tick feeding or intradermal injection of salivary gland proteins, suggesting a superimposed Th2 response. Infestation induced TCR transgenic CD4+ T cells to divide more frequently as measured by CFSE dilution, but more notably these CD4+ T cells also gained the capacity to express IL-4. Intracellular levels of IL-4 were significantly increased. A second infestation administered 14 days after a primary exposure to ticks resulted in partially reduced CFSE dilution with no change in IL-4 expression when compared to one exposure to ticks. Intradermal inoculation of salivary gland extracts from both male and female ticks also induced IL-4 expression. Conclusion This is the first report of the influence of a metastriate tick on the cytokine profile of antigen specific CD4+ T cells. Blood feeding

  17. Tools to fiht ticks: A never-ending story? News from the front of green acaricides and photosensitizers

    Directory of Open Access Journals (Sweden)

    Giovanni Benelli

    2016-08-01

    Full Text Available Nowadays, parasitology is facing a number of crucial challenges, including the urgent request of effective control tools against arthropod vectors of medical and veterinary importance. Ticks transmit at least the same amount or even more pathogen species than any other group of blood-feeding arthropods worldwide affecting humans and animals. Besides the development of vaccines against viruses vectored by ticks, integrated pest management practices aimed at reducing tick interactions with livestock, emerging pheromone-based control tools, and few biological control agents have been also proposed. The extensive employ of acaricides and tick repellents still remains the two most effective and ready-to-use strategies. However, the use of synthetic acaricides is limited by the development of resistance in several tick species as well as by heavy environmental concerns. In this scenario, the exploitation of botanicals as cheap and effective sources of tick repellents may represent a valid alternative, and the preservation of ethnobotanical information on the repellent and acaricidal potential of plants is crucial. On the other hand, novel photodynamic acaricides have been recently described, with a toxicity against ticks which far exceed some of the acaricides currently marketed (e.g. tetramethrin. In this brief review, I provide a focus on some hot news in tick control, with special reference to tick repellents of botanical origin and new photodynamic fluorescent acaricides. To my mind, knowledge on both the mentioned research issues may help researchers to build valuable roadmaps to boost tick control programs worldwide.

  18. Room temperature synthesis of water-repellent polystyrene nanocomposite coating

    International Nuclear Information System (INIS)

    Guo Yonggang; Jiang Dong; Zhang Xia; Zhang Zhijun; Wang Qihua

    2010-01-01

    A stable superhydrophobic polystyrene nanocomposite coating was fabricated by means of a very simple and easy method. The coating was characterized by scanning electron microscopy and X-ray photoelectron spectrum. The wettability of the products was also investigated. By adding the surface-modified SiO 2 nanoparticles, the wettability of the coating changed to water-repellent superhydrophobic, not only for pure water, but also for a wide pH range of corrosive liquids. The influence of the drying temperature and SiO 2 content on the wettability of the nanocomposite coating was also investigated. It was found that both factors had little or no significant effect on the wetting behavior of the coating surface.

  19. Notes on the blood-feeding behavior of Aedes albopictus (Diptera : Culicidae) in Cameroon

    OpenAIRE

    Kamgang, Basile; Nchoutpouen, Elysée; Simard, Frédéric; Paupy, Christophe

    2012-01-01

    Abstract Background The invasive mosquito Aedes albopictus is often considered a poor vector of human pathogens, owing to its catholic feeding behavior. However, it was recently incriminated as a major vector in several Chikungunya epidemics, outside of its native range. Here we assessed two key elements of feeding behavior by Ae. albopictus females in Yaoundé, Cameroon, Central Africa. Host preference was explored and the human-biting activity of females was monitored over 24 h to determine ...

  20. Pesticidal and pest repellency activities of a plant derived triterpenoid 2α,3β,21β,23,28-penta hydroxyl 12-oleanene against Tribolium castaneum

    Directory of Open Access Journals (Sweden)

    Alam Khan

    2014-01-01

    Full Text Available BACKGROUND: Tribolium castaneum (Herbst is a major pest of stored grain-based products, and cause severe damage to cereal grains throughout the world. The present investigation was aimed to determine the pesticidal and pest repellent activities of 2α,3β,21β,23,28-penta hydroxyl 12-oleanene against T. castaneum. The compound 2α,3β,21β,23,28-penta hydroxyl 12-oleanene is a triterpenoid which was isolated from the roots of Laportea crenulata Gaud. Surface film technique was used for pesticidal screening, whereas, pest repellency property of the triterpenoid was determined by filter paper disc method. RESULTS: At 24 hours of exposure duration, significant mortality records (80% and 86% were observed at doses 0.88 and 1.77 mg/cm². No significant change in mortality records was observed when duration of exposure was increased up to 48 hours. The triterpenoid showed significant repellency activity at doses 0.47 and 0.94 mg/cm². CONCLUSION: These data suggest that the triterpenoid 2α,3β,21β,23,28-penta hydroxyl 12-oleanene possess both pesticidal and pest repellency activities against T. castaneum and can be used in controlling the pest of grain-based products.