Kurokawa, Kenji; Yoshii, Manabu; Oda, Tsutomu; Kato, Katsutomo; Uchida, Keikichi; Eshita, Yuki; Tahara, Hiroyuki; Mine, Mariko; Ogawa, Yasunori
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.
Diaz-Badillo, Alvaro; Bolling, Bethany G; Perez-Ramirez, Gerardo; Moore, Chester G; Martinez-Munoz, Jorge P; Padilla-Viveros, America A; Camacho-Nuez, Minerva; Diaz-Perez, Alfonso; Beaty, Barry J; Munoz, Maria de Lourdes
Culex spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV) detected in at least 34 species of mosquitoes in the United States. In North America, Culex pipiens pipiens, Culex pipiens quinquefasciatus, and Culex tarsalis are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of Culex pipiens complex mosquitoes and hybrids in Mexico City. Culex pipiens pipiens preferentially feed on avian hosts; Culex pipiens quinquefasciatus have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of Culex pipiens complex mosquitoes and their hybrids. Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as Culex, Culiseta or Ochlerotatus by morphological analysis. Within the genus Culex, specimens were further identified as Culex tarsalis or as belonging to the Culex pipiens complex. Members of the Culex pipiens complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio) of the male genitalia and also by using diagnostic primers designed for the Ace.2 gene. Culex pipiens quinquefasciatus was the most abundant form collected. Important WNV vectors species, Cx. p. pipiens, Cx. p. quinquefasciatus and Cx. tarsalis, are all present in Mexico City. Hybrids of Cx. p. pipiens and Cx. p. quinquefasciatus were also collected and identified. The
Full Text Available Abstract Background Culex spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV detected in at least 34 species of mosquitoes in the United States. In North America, Culex pipiens pipiens, Culex pipiens quinquefasciatus, and Culex tarsalis are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of Culex pipiens complex mosquitoes and hybrids in Mexico City. Culex pipiens pipiens preferentially feed on avian hosts; Culex pipiens quinquefasciatus have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of Culex pipiens complex mosquitoes and their hybrids. Results Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as Culex, Culiseta or Ochlerotatus by morphological analysis. Within the genus Culex, specimens were further identified as Culex tarsalis or as belonging to the Culex pipiens complex. Members of the Culex pipiens complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio of the male genitalia and also by using diagnostic primers designed for the Ace.2 gene. Culex pipiens quinquefasciatus was the most abundant form collected. Conclusions Important WNV vectors species, Cx. p. pipiens, Cx. p. quinquefasciatus and Cx. tarsalis, are all present in Mexico City. Hybrids of Cx. p. pipiens and Cx. p
Thiemann, T C; Lemenager, D A; Kluh, S; Carroll, B D; Lothrop, H D; Reisen, W K
West Nile virus (family Flaviviridae, genus Flavivirus, WNV) is now endemic in California across a variety of ecological regions that support a wide diversity of potential avian and mammalian host species. Because different avian hosts have varying competence for WNV, determining the blood-feeding patterns of Culex (Diptera: Culicidae) vectors is a key component in understanding the maintenance and amplification of the virus as well as tangential transmission to humans and horses. We investigated the blood-feeding patterns of Culex tarsalis Coquillett and members of the Culex pipiens L. complex from southern to northern California. Nearly 100 different host species were identified from 1,487 bloodmeals, by using the mitochondrial gene cytochrome c oxidase I (COI). Cx. tarsalis fed on a higher diversity of hosts and more frequently on nonhuman mammals than did the Cx. pipiens complex. Several WNV-competent host species, including house finch and house sparrow, were common bloodmeal sources for both vector species across several biomes and could account for WNV maintenance and amplification in these areas. Highly competent American crow, western scrub-jay and yellow-billed magpie also were fed upon often when available and are likely important as amplifying hosts for WNV in some areas. Neither species fed frequently on humans (Cx. pipiens complex [0.4%], Cx. tarsalis [0.2%]), but with high abundance, both species could serve as both enzootic and bridge vectors for WNV.
Fahd A. Al-Mekhlafi
Full Text Available Effects of methanol extracts of Xanthium strumarium on different cancer cell lines and on the mortality rates of Aedes caspius, Culex pipiens (Diptera: Culicidae were investigated. Among the cell lines tested, the Jurkat cell line was the most sensitive to the methanol extract and ethyl acetate fraction, with reported LC50 values of 50.18 and 48.73 μg/ml respectively. Conversely, methanol extracts were not that toxic to the A549 cell line though the toxicity increased on further purification. The percentage of growth inhibition was dose dependent for the methanol extract and ethyl acetate fraction. The ethyl acetate fraction showed higher toxicity to all cell lines tested when compared to the methanol extract. The results showed that methanol extracts of plant seeds caused 100% mortality of mosquito larvae at a concentration of 1000 μg/ml after 24 h of treatment. The LC50 and LC90 values of X. strumarium were found to be 531.07 and 905.95 μg/ml against Ae. caspius and 502.32 and 867.63 μg/ml against Cx. Pipiens, respectively. From the investigations, it was concluded that the crude extract of X. strumarium showed a weak potential for controlling the larval instars of Ae. caspius and Cx. pipiens. However, on further purification the extract lost the larvicidal activity. The ethyl acetate fraction showed higher toxicity to all cell lines tested when compared to the methanol extract. The ethyl acetate fraction investigated in this study appears to have a weak larvicidal activity but a promising cytotoxic activity. Future studies will include purification and investigation in further detail of the action of X. strumarium on Cancer Cell Lines and mosquitoes.
Al-Mekhlafi, Fahd A; Abutaha, Nael; Mashaly, Ashraf M A; Nasr, Fahd A; Ibrahim, Khalid E; Wadaan, Mohamed A
Effects of methanol extracts of Xanthium strumarium on different cancer cell lines and on the mortality rates of Aedes caspius, Culex pipiens (Diptera: Culicidae) were investigated. Among the cell lines tested, the Jurkat cell line was the most sensitive to the methanol extract and ethyl acetate fraction, with reported LC 50 values of 50.18 and 48.73 μg/ml respectively. Conversely, methanol extracts were not that toxic to the A549 cell line though the toxicity increased on further purification. The percentage of growth inhibition was dose dependent for the methanol extract and ethyl acetate fraction. The ethyl acetate fraction showed higher toxicity to all cell lines tested when compared to the methanol extract. The results showed that methanol extracts of plant seeds caused 100% mortality of mosquito larvae at a concentration of 1000 μg/ml after 24 h of treatment. The LC 50 and LC 90 values of X. strumarium were found to be 531.07 and 905.95 μg/ml against Ae. caspius and 502.32 and 867.63 μg/ml against Cx. Pipiens, respectively. From the investigations, it was concluded that the crude extract of X. strumarium showed a weak potential for controlling the larval instars of Ae. caspius and Cx. pipiens . However, on further purification the extract lost the larvicidal activity. The ethyl acetate fraction showed higher toxicity to all cell lines tested when compared to the methanol extract. The ethyl acetate fraction investigated in this study appears to have a weak larvicidal activity but a promising cytotoxic activity. Future studies will include purification and investigation in further detail of the action of X. strumarium on Cancer Cell Lines and mosquitoes.
Cetin, H; Yanikoglu, A; Kocak, O; Cilek, J E
The larvicidal activity of chlorpyrifos-methyl and temephos was evaluated against Culex pipiens L. (Diptera: Culicidae) in septic tanks in Antalya, Turkey. Chlorpyrifos-methyl (Pyrifos MT 25 emulsifiable concentrate [EC] ) was evaluated at application rates of 0.04, 0.08, and 0.12 mg active ingredient (AI)/liter, and temephos (Temeguard 50 EC) was evaluated at 0.02, 0.04, and 0.06 mg (AI)/liter during a 21-d study. Generally, overall larval reduction in septic tanks from single- and multifamily dwellings treated with either larvicide was significantly greater than pretreatment levels and control tanks for the duration of the study. At 14 d posttreatment, duration of control was greatest in multifamily tanks treated with chlorpyrifos-methyl at the highest application rate with similar levels of control through 21 d for single-family dwellings (range 97-100%). Septic tanks from both types of family dwellings treated at the highest application rate of temephos resulted in >90% reduction through day 21 (range 91-100%). Laboratory bioassays of septic tank water treated at field application rates, without daily dilution, revealed that complete larval mortality was achieved for 21 d at each application rate and formulation. It is thought that daily addition of water and organic matter to the septic tanks in the single and multifamily dwellings influenced the duration of effectiveness of the larvicides.
Gomes, Bruno; Sousa, Carla A; Vicente, José L; Pinho, Leonor; Calderón, Isabel; Arez, Eliane; Almeida, António Pg; Donnelly, Martin J; Pinto, João
Two biological forms of the mosquito Culex pipiens s.s., denoted pipiens and molestus, display behavioural differences that may affect their role as vectors of arboviruses. In this study, the feeding patterns of molestus and pipiens forms were investigated in Comporta (Portugal), where high levels of inter-form admixture have been recorded. Indoor and outdoor mosquito collections were performed in the summer of 2010. Collected Cx. pipiens s.l. females were molecularly identified to species and form by PCR and genotyped for six microsatellites. The source of the blood meal in post-fed females was determined by ELISA and mitochondrial DNA sequencing. The distribution of the forms differed according to the collection method. The molestus form was present only in indoor collections, whereas pipiens and admixed individuals were sampled both indoors and outdoors. In both forms, over 90% of blood meals were made on avian hosts. These included blood meals taken from Passeriformes (Passer domesticus and Turdus merula) by females caught resting inside domestic shelters. Genetic structure and blood meal analyses suggest the presence of a bird biting molestus population in the study area. Both forms were found to rest indoors, mainly in avian shelters, but at least a proportion of females of the pipiens form may bite outdoors in sylvan habitats and then search for anthropogenic resting sites to complete their gonotrophic cycle. This behaviour may potentiate the accidental transmission of arboviruses to humans in the region.
Cetin, Huseyin; Yanikoglu, Atila; Cilek, James E
The naturally-derived insecticide spinosad (Conserve SC) was evaluated against larval Culex pipiens L. (Diptera: Culicidae) under laboratory and field conditions in Antalya, Turkey. Laboratory bioassays showed that the 24 h LC50 and LC90 against late 3rd and early 4th instars were estimated at 0.027 and 0.111 parts per million, respectively, while adult emergence was eliminated at concentrations above 0.06 ppm. Larval mortality from septic tanks that were treated with spinosad at rates of 25, 50, 100, and 200 g ai/ha ranged between 22 to 78% 1 day after application. At 7 days post-treatment, larval mortality ranged from 2 to 50% and at 14 days mortality was septic tanks treated at 100 and 200 g ai/ha resulted in an elimination of Cx. pipiens larvae 7 days after treatment. After this time, larval reduction declined to 79 and 83%, respectively, 14 days after treatment. Larval reduction in septic tanks treated at the two lowest rates (i.e. 25 and 50 g ai/ha) ranged from 14 to 74% during the 14-day study. These results indicated that spinosad can be considered an effective larvicide for treatment of septic tanks against Cx. pipiens.
Fouad El-Akhal; Abdelhakim El Ouali Lalami; Yassine Ez Zoubi; Hassane Greche; Raja Guemmouh
Objective:To evaluate the larvicidal activity of essential oil of Origanum majorana (Lamiaceae) cultivated in Morocco against Culex pipiens (Diptera:Culicidae). Methods: The analysis and the identification of the various constituents of essential oil were carried out by gas chromatography coupled with mass spectrometry. Biological test was performed according to a standard methodology inspired by the World Health Organization protocol with slight modification. Results:This oil mainly consisted of monoterpene and sesquiterpenes. The majority compounds are 4-terpinene (28.96%), γ-terpinene (18.57%), α-terpinene (12.72%) and sabinene (8.02%). The lethal concentrations (LC50 and LC90) measured for the essential oil Origanum majorana, were respectively of the order of 258.71 mg/L and 580.49 mg/L.
Full Text Available Background. Outbreaks of the West Nile virus infection were reported in Morocco in 1996, 2003, and 2010. Culex pipiens was strongly suspected as the vector responsible for transmission. In the North center of Morocco, this species has developed resistance to synthetic insecticides. There is an urgent need to find alternatives to the insecticides as natural biocides. Objective. In this work, the insecticidal activity of the extract of the local plant Nerium oleander, which has never been tested before in the North center of Morocco, was studied on larval stages 3 and 4 of Culex pipiens. Methods. Biological tests were realized according to a methodology inspired from standard World Health Organization protocol. The mortality values were determined after 24 h of exposure and LC50 and LC90 values were calculated. Results. The extract had toxic effects on the larvae of culicid mosquitoes. The ethanolic extract of Nerium oleander applied against the larvae of Culex pipiens has given the lethal concentrations LC50 and LC90 in the order of 57.57 mg/mL and 166.35 mg/mL, respectively. Conclusion. This investigation indicates that N. oleander could serve as a potential larvicidal, effective natural biocide against mosquito larvae, particularly Culex pipiens.
Full Text Available Background: During recent years transmission of Dirofilaria immitis (dog heart worm by Culex pipiens and West Nile virus have been reported from Iran. The present study was preformed for evaluating the susceptibility status of Cx. pipiens collected from capital city of Tehran, Iran.Methods: Four Insecticides including: DDT 4%, Lambdacyhalothrin 0.05%, Deltamethrin 0.05% and Cyfluthrin 0.15 % according to WHO standard methods were used for evaluating the susceptibility status of Cx. pipiens from Tehran moreover For comparison susceptibility status a Laboratory strain also was used. Bioassay data were analyzed using Probit program. The lethal time for 50% and 90% mortality (LT50 and LT90 values were calculated from regression line.Results: The susceptibility status of lab strain of Cx. pipiens revealed that it is susceptible to Lambdacyhalothrin, Deltamethrin, Cyfluthrin and resistant to DDT. Moreover cyfluthrin with LT50=36 seconds and DDT with LT50=3005 seconds had the least and most LT50s. Field population was resistance to all tested insecticides and DDT yielded no mortality.Conclusion: Highly resistance level against all WHO recommended imagicides were detected in field populations. We suggest more biochemical and molecular investigations to detect resistance mechanisms in the field population for further decision of vector control.
Full Text Available The aim was to survey the specific factors, which cause to decrease blood feeding of mosquitoes important to succeed vector control.Larval collection was carried out from fixed and variable breeding places of Yazd County, central Iran in 2009. Autogeny-Anautogeny, Stenogamy-Eurygamy, and blood preference of Culex pipiens were studied using standard mosquito cages blood meal source for Cx. pipiens females considered as the chickens and human and fed females were kept in insectary condition (16:8 L: D, 27±3 °C and 70±10% RH. The data were analyzed using SPSS Ver. 11.5 soft ware.Totally, 96 females' mosquitoes were tested for Stenogamy versus Eurygamy and 122 for blood preference assay. In the small cages (20 × 20 × 20cm and large cage (60 × 40 × 60cm, the ability of mating and insemination rates were 60.0 and 67.0%, respectively. In spite of Cx. pipiens fed from sucrose 5%, none of them laying eggs in 60 × 40 × 60 cages during the study. This finding indicated the Anautogeny behavior of this species. This species was found of low tendency to human blood and almost 4 fold fed on chicken.The occurrence of Steno-Eurygamy, Anautogeny, and Ornithophilic behaviors of Cx. Pipiens was noted. More studies need to be carried out about the bionomics of this species to gain more data about the ecophysiological and behavioral characteristics in other parts of Iran.
Traboulsi, Abdallah F; El-Haj, Samih; Tueni, Marie; Taoubi, Khalil; Nader, Natalie Abi; Mrad, Abir
The insecticidal activities of essential oil extracts from leaves, flowers and roots of aromatic plants against fourth-instar larvae of the mosquito Culex pipiens molestus Forskal were determined. Extracts of Foeniculum vulgare Mill were the most toxic, followed by those of Ferula hermonis Boiss, Citrus sinensis Osbeck, Pinus pinea L, Laurus nobilis L and Eucalyptus spp with LC50 values of 24.5, 44.0, 60.0, 75.0, 117.0 and 120.0 mg litre(-1), respectively. Combination tests between the LC50 and the maximum sub-lethal concentration (MSLC) were determined. Over 20 major components were identified in extracts from each plant species tested. Five essential oils and nine pure components were studied for their repellency against mosquito bites. Terpineol and 1,8-cineole were the most effective against Culex pipiens molestus bites offering complete protection for 1.6 and 2 h, respectively.
Full Text Available "nAbstract "nBackground: Culex pipiens complex shows variations in morphological and biological characters including different biological forms and has medical and veterinary importance. Because of having morphological variations, sometimes it is not easy to separate this species from Cx. quinquefasciatus and Cx. torrentium. The aim of this study was to identify the Culex pipiens complex species in order to use in control programs in the future. "nMethods: This study was carried out in two randomly selected rural villages in Yazd County, eastern Iran using dipping technique from April to October 2009. The data were analyzed using SPSS software version 16. "nResults: Average of siphon index in fourth-instrar larvae was 3.86±0.03, the minimum and maximum were calculated 2.43 and 5.14, respectively. Siphon/Saddle index was measured as average, minimum and maximum 3.2±0.2, 2.78, and 4.42 respectively. In our study, only 4 specimens had single seta 1 on segments III and VI (2.5% and the remaining beard double seta (97.5%. The maximum 3-6 branches seta 1a-S and 1b-S (95% were observed on siphon. "nConclusion: More populations of Culex pipiens from different areas of Iran need to be studied to gain complete information about the taxonomy and ecology of the species in the country. "n "nKeywords: Culex pipiens complex, larvae, taxonomy, Iran
Victor A. Brugman
Full Text Available Over the past three decades, a range of mosquito-borne viruses that threaten public and veterinary health have emerged or re-emerged in Europe. Mosquito surveillance activities have highlighted the Culex pipiens species complex as being critical for the maintenance of a number of these viruses. This species complex contains morphologically similar forms that exhibit variation in phenotypes that can influence the probability of virus transmission. Critical amongst these is the choice of host on which to feed, with different forms showing different feeding preferences. This influences the ability of the mosquito to vector viruses and facilitate transmission of viruses to humans and domestic animals. Biases towards blood-feeding on avian or mammalian hosts have been demonstrated for different Cx. pipiens ecoforms and emerging evidence of hybrid populations across Europe adds another level of complexity to virus transmission. A range of molecular methods based on DNA have been developed to enable discrimination between morphologically indistinguishable forms, although this remains an active area of research. This review provides a comprehensive overview of developments in the understanding of the ecology, behaviour and genetics of Cx. pipiens in Europe, and how this influences arbovirus transmission.
Full Text Available Background: The aim of the current study was to develop a marking technique as an internal marker to mark post blood meal mosquitoes by using stable phosphate isotope 32P and determine the optimal concentration of it.Methods: An isotonic physiological saline solution, containing different concentration of radioactive isotope 32P-labeled disodium phosphate (Na2H32PO4 was injected into rabbits via the jugular vein in the laboratory. Emerged Cx. pipiens were marked after feeding on rabbit. At the same time, the labeled conditions of emerged Cx. pipiens were also measured by placing feces of No. 6 rabbit into containers with mosquito larvae and pupae inside.Results: According to the label condition of Cx. pipiens after taking blood and the effect of different dosage Na2H32PO4 on rabbit health, the optimal concentration of radioactive isotope was determined, that is, 0.1211 mCi/kg. By placing feces of No. 6 rabbit into containers with mosquito larvae and pupae inside, the emerged mosquitoes were also labeled. Therefore, feeding mosquitoes on the animal injected with radioactive Na2H32PO4 was more practical for detecting and tracing mosquitoes.Conclusion: The method was less time-consuming, more sensitive and safer. This marking method will facilitate post-bloodmeal studies of mosquitoes and other blood-sucking insects.
Hernández-Triana, Luis M.; Medlock, Jolyon M.; Fooks, Anthony R.; Carpenter, Simon; Johnson, Nicholas
Over the past three decades, a range of mosquito-borne viruses that threaten public and veterinary health have emerged or re-emerged in Europe. Mosquito surveillance activities have highlighted the Culex pipiens species complex as being critical for the maintenance of a number of these viruses. This species complex contains morphologically similar forms that exhibit variation in phenotypes that can influence the probability of virus transmission. Critical amongst these is the choice of host on which to feed, with different forms showing different feeding preferences. This influences the ability of the mosquito to vector viruses and facilitate transmission of viruses to humans and domestic animals. Biases towards blood-feeding on avian or mammalian hosts have been demonstrated for different Cx. pipiens ecoforms and emerging evidence of hybrid populations across Europe adds another level of complexity to virus transmission. A range of molecular methods based on DNA have been developed to enable discrimination between morphologically indistinguishable forms, although this remains an active area of research. This review provides a comprehensive overview of developments in the understanding of the ecology, behaviour and genetics of Cx. pipiens in Europe, and how this influences arbovirus transmission. PMID:29473903
Nikos G. Chorianopoulos
Full Text Available The chemical composition of the essential oils of the wild growing plants of Greek S. spinosa L., S. parnassica subsp. parnassica Heldr.& Sart ex Boiss., S. thymbra and S. montana were determined by GC and GC/MS analysis. The larvicidal activities of the essential oils were assayed against Culex pipiens biotype molestus. The analytical data indicated that various monoterpene hydrocarbons and phenolic monoterpenes constitute the major constituents of the oils, but their concentration varied greatly among the oils examined. The bioassay results indicated that the oils possess significant larvicidal activities and represent an inexpensive source of natural substances mixture that exhibit potentials for use to control the mosquito larvae.
Richards, Stephanie L; Lord, Cynthia C; Pesko, Kendra N; Tabachnick, Walter J
Interactions between environmental and biological factors affect the vector competence of Culex pipiens quinquefasciatus for West Nile virus. Three age cohorts from two Cx. p. quinquefasciatus colonies were fed blood containing a low- or high-virus dose, and each group was held at two different extrinsic incubation temperatures (EIT) for 13 days. The colonies differed in the way that they responded to the effects of the environment on vector competence. The effects of mosquito age on aspects of vector competence were dependent on the EIT and dose, and they changed depending on the colony. Complex interactions must be considered in laboratory studies of vector competence, because the extent of the genetic and environmental variation controlling vector competence in nature is largely unknown. Differences in the environmental (EIT and dose) and biological (mosquito age and colony) effects from previous studies of Cx. p. quinquefasciatus vector competence for St. Louis encephalitis virus are discussed.
María C Tranchida
Full Text Available Copepods from La Plata, Argentina were investigated to characterize the local community of larvivorous copepods inhabiting mosquito breeding sites and to identify new predator species of the mosquitoes which occur in artificial containers, Aedes aegypti and Culex pipiens. Diversity of larvivorous cyclopoids was highest in permanent pools. Predation by sex and age, selectivity on mosquito species, and daily predation rate during five days were studied for Acanthocyclops robustus, Diacyclops uruguayensis, Macrocyclops albidus and Mesocyclops longisetus. Female copepods presented the highest predatory capacity. No predatory preference for mosquito species was found. According to overall predation potential, copepods were ranked as follows: D. uruguayensis Se hizo una prospección de copépodos en La Plata, Argentina, con los objetivos de caracterizar la comunidad local de copépodos larvívoros en sitios de cría de mosquitos, e identificar nuevas especies depredadoras de los mosquitos de contenedores artificiales Aedes aegypti y Culex pipiens. La diversidad de ciclopoides larvívoros fue máxima en charcos permanentes. Se examinó la depredación por sexos y edad, la selectividad por especies de mosquito, y la tasa de depredación diaria durante cinco días en Acanthocyclops robustus, Diacyclops uruguayensis, Macrocyclops albidus y Mesocyclops longisetus. Los copépodos hembra presentaron la capacidad depredadora más alta. No se encontró preferencia por alguna especie de mosquito. De acuerdo al potencial de depredación en general, los copépodos se ordenan así: D. uruguayensis < A. robustus < M. albidus < M. longisetus. También se evaluó la tolerancia a la desecación del hábitat y la capacidad de resistir en agua de contenedores artificiales. D. uruguayensis y A. robustus sobrevivieron en condiciones de sequía, pero D. uruguayensis presentó menor supervivencia en agua de floreros de cementerio. M. albidus no sobrevivió condiciones de
Richards, Stephanie L; Anderson, Sheri L; Yost, Samantha A
Culex pipiens quinquefasciatus were fed blood meals from a live chicken (LC), chicken blood in Alsever's (AC) solution, defibrinated bovine blood (DB), or bovine blood in citrate (CB) and incubated at 28° C. The effects of different blood meal sources were evaluated with respect to rates of blood feeding and reproduction (i.e., fecundity and fertility) over two gonotrophic cycles. Mosquitoes that fed on the first blood meal were subjected to a second blood meal as follows (first blood meal / second blood meal): LC/LC, LC/DB, DB/DB, CB/CB, AC/AC. Fecundity and fertility of Cx. p. quinquefasciatus were significantly (P blood; however, fecundity and fertility in different treatment groups varied by gonotrophic cycle. These results contribute to our understanding of the impact of blood meal source on feeding and reproduction in Cx. p. quinquefasciatus. The potential impacts of blood meal source on virus transmission experiments are discussed. © 2012 The Society for Vector Ecology.
Predation and control efficacies of Misgurnus mizolepis (Cypriniformes: Cobitidae) toward Culex pipiens molestus (Diptera: Culicidae) and fish toxicity of temephos in laboratory and septic tank conditions.
Chae, Seong Chun; Kwon, Young Hyun; Min, Kyung Il; Kim, Hyung Soo; Kim, Nam-Jin; Kim, Jun-Ran; Son, Bong Gi; Ahn, Young-Joon
Culex pipiens molestus Forskal (Diptera: Culicidae) is the dominant mosquito species in septic tanks in South Korea. An assessment was made of the biological control potential of mud loaches, Misgurnus mizolepis Günther (Cypriniformes: Cobitidae), toward Cx. p. molestus larvae in laboratory and septic tanks. Results were compared with those of temephos 20% emulsifiable concentrate. In laboratory tests, all mud loaches survived on sedimentation chamber- and effluent chamber-collected water of aerobic septic tanks (ASTs), whereas all mud loaches died within 3-12 h after introduction into sedimentation chamber- and effluent chamber-collected water of anaerobic septic tanks, Gill hyperplasia and hemorrhages at the bases of pectoral fins were detected in all dead mud loaches. These appeared to have been caused by bacterial disease, rather than the physical and chemical characteristics of the septic tank water. A mud loach consumed an average range of 1,072-1,058 larvae of Cx. p. molestus in the AST water at 24 h. At the manufacturer's recommended rate (10 ml/ton) in the AST water, the temephos formulation did not cause fish mortality. In the AST experiment, predation of mosquito larvae by mud loaches at a release rate of one fish per 900 mosquito larvae resulted in complete mosquito control from the third day after treatment throughout the 18-wk survey period, compared with temephos 20% emulsifiable concentrate-treated AST water (reduction rate, 40% at 28 days after treatment). Reasonable mosquito control in aerobic septic tanks can be achieved by mosquito breeding season stocking of a rate of one mud loach per 900 mosquito larvae.
Gardner, Allison M; Allan, Brian F; Frisbie, Lauren A; Muturi, Ephantus J
Exotic invasive plants alter the structure and function of native ecosystems and may influence the distribution and abundance of arthropod disease vectors by modifying habitat quality. This study investigated how invasive plants alter the ecology of Culex pipiens, an important vector of West Nile virus (WNV) in northeastern and midwestern regions of the United States. Field and laboratory experiments were conducted to test the hypothesis that three native leaf species (Rubus allegheniensis, blackberry; Sambucus canadensis, elderberry; and Amelanchier laevis, serviceberry), and three exotic invasive leaf species (Lonicera maackii, Amur honeysuckle; Elaeagnus umbellata, autumn olive; and Rosa multiflora, multiflora rose) alter Cx. pipiens oviposition site selection, emergence rates, development time, and adult body size. The relative abundance of seven bacterial phyla in infusions of the six leaf species also was determined using quantitative real-time polymerase chain reaction to test the hypothesis that variation in emergence, development, and oviposition site selection is correlated to differences in the diversity and abundance of bacteria associated with different leaf species, important determinants of nutrient quality and availability for mosquito larvae. Leaf detritus from invasive honeysuckle and autumn olive yielded significantly higher adult emergence rates compared to detritus from the remaining leaf species and honeysuckle alleviated the negative effects of intraspecific competition on adult emergence. Conversely, leaves of native blackberry acted as an ecological trap, generating high oviposition but low emergence rates. Variation in bacterial flora associated with different leaf species may explain this asymmetrical production of mosquitoes: emergence rates and oviposition rates were positively correlated to bacterial abundance and diversity, respectively. We conclude that the displacement of native understory plant species by certain invasive shrubs
Full Text Available The larvicidal activity of the crude petroleum ether, ethyl acetate, acetone, chloroform and ethanol extracts of Amorpha fruticosa seeds was individually assayed for toxicity against the early fourth-instar larva of the mosquito, Culex pipiens pallens after 24 h exposure. Of the tested extracts, the ethanol one exhibited the highest larvicidal activity (LC50 = 22.69 mg/L. Amorphigenin (8'-hydroxyrotenone, a rotenoid compound which exhibits a strong larvicidal activity with LC50 and LC90 values of 4.29 and 11.27 mg/L, respectively, was isolated from the ethanol extract by column chromatograpy. Its structure was elucidated by 1H-NMR, UV and IR spectral data. Furthermore, investigation of amorphigenin’s effects on mitochondrial complex I activity and protein synthesis in C. pipiens pallens larvae reveals that amorphigenin decreases mitochondrial complex I activities to 65.73% at 10.45 μmol/L, compared to the control, when NADH were used as the substrate. Meanwhile, amorphigenin at 10.45 μmol/L also caused a 1.98-fold decrease in protein content, compared to the control larvae treated with acetone only.
Richards, Stephanie L; Lord, Cynthia C; Pesko, Kendra; Tabachnick, Walter J
Complex interactions between environmental and biological factors influence the susceptibility of Culex pipiens quinquefasciatus to St. Louis encephalitis virus and could affect the epidemiology of virus transmission. Similar interactions could have epidemiologic implications for other vector-virus systems. We conducted an experiment to examine four such factors in combination: mosquito age, extrinsic incubation temperature (EIT), virus dose, and colony. The proportion of mosquitoes with body infections or disseminated infections varied between colonies, and was dependant on age, EIT, and dose. We also show that the probability of a body or leg infection interacted in complex ways between colonies, ages, EITs, and doses. The complex interactive effects of environmental and biological factors must be taken into account for studies of vector competence and epidemiology, especially when laboratory studies are used to generalize to natural transmission dynamics where the extent of variation is largely unknown.
Ashraf M Ahmed
Full Text Available Background: The incidence of mosquito-borne diseases and the resistance of mosquitoes to conventional pesticides have recently caused a panic to the authorities in the endemic countries. This study was conducted to identify native larvicidal biopesticides against Culex pipiens for utilization in the battle against mosquito-borne diseases.Methods: Larvicidal activities of new indigenous Bacillus thuringiensis isolates and crude toxin complexes (TCs of two nematode bacterial-symbionts, Photorhabdus luminescens akhurstii (HRM1 and Ph. luminescens akhurstii (HS1 that tested against Cx. pipiens. B. thuringiensis isolates were recovered from different environmental samples in Saudi Arabia, and the entomopathogenic nematodes, Heterorhabditis indica (HRM1 and He. sp (HS1 were isolated from Egypt. Larvicidal activities (LC50 and LC95 of the potentially active B. thuringiensis strains or TCs were then evaluated at 24 and 48h post-treatment.Results: Three B. thuringiensis isolates were almost as active as the reference B. thuringiensis israelensis (Bti-H14, and seven isolates were 1.6–5.4 times more toxic than Bti-H14. On the other hand, the TCs of the bacterial symbionts, HRM1 and HS1, showed promising larvicidal activities. HS1 showed LC50 of 2.54 folds that of HRM1 at 24h post-treatment. Moreover, histopathological examinations of the HS1-treated larvae showed deformations in midgut epithelial cells at 24h post-treatment.Conclusion: Synergistic activity and molecular characterization of these potentially active biocontrol agents are currently being investigated. These results may lead to the identification of eco-friend mosquito larvicidal product(s that could contribute to the battle against mosquito-borne diseases.
Richards, Stephanie L; Anderson, Sheri L; Lord, Cynthia C; Smartt, Chelsea T; Tabachnick, Walter J
Culex pipiens quinquefasciatus Say fed blood containing 6.8 +/- 0.3 logs (mean +/- SE) plaque-forming units of West Nile virus (WNV)/ml were maintained at 28 degrees C for incubation periods (IP) of 7, 14, or 21 d. Several attributes of vector competence were determined at each IP using quantitative real-time reverse transcriptase polymerase chain reaction to estimate plaque forming unit equivalents including: infection rate (WNV-positive abdomens), dissemination rate (WNV-positive legs or thoraces), combined dissemination rate (WNV-positive legs and thoraces), transmission rate (WNV-positive saliva), and WNV titers in abdomens, legs, thoraces, and saliva. Each rate increased or was equivalent with increasing IP. Mosquitoes transmitting WNV in saliva also had significantly higher IP-dependent WNV titers in abdomens, legs, and thoraces. Titers of WNV in abdomens were significantly correlated with titers in legs and thoraces, but the degree of association changed with IP. However, titers of abdomens, legs, and thoraces were not correlated with WNV presence or titer in the saliva. The results show that WNV presence or titer in the saliva of infected Cx. p. quinquefasciatus was not directly influenced by processes involved in WNV replication in other tissues. The processes controlling midgut infection and escape are, in part, independent from the infection processes in other tissues. The relationship between infection, dissemination, and transmission varied over time. The infection and replication of WNV in different tissues is likely influenced by different barriers encountered during the extrinsic incubation period. The significance of these observations for understanding vector competence is discussed.
Full Text Available Las larvas de los mosquitos Aedes aegypti (Linneo y Culex pipiens Linneo pueden criar conjuntamente en pequeños contenedores artificiales de agua, se genera así una competencia interespecífica y/o intraespecífica. El objetivo de este trabajo fue comparar la magnitud relativa de la competencia intra e interespecífica en A. aegypti y C. pipiens, generada durante el desarrollo larval en contenedores artificiales. Las variables medidas como respuesta fueron la supervivencia y el tiempo de desarrollo larval, y la biomasa total producida en estado de pupa. Se criaron larvas de ambos mosquitos en neumáticos de automóvil con agua declorinada y hojarasca. Se introdujeron larvas recién eclosionadas de acuerdo a la densidad (δ estimada según un censo previo de A. aegypti y C. pipiens. Se realizaron los siguientes tratamientos agregando larvas de: (1 A. aegypti hasta alcanzar δ A. aegypti determinada según el censo previo, (2 C. pipiens hasta δ C. pipiens del censo previo, (3 A. aegypti hasta alcanzar la suma de δ A. aegypti y δ C. pipiens del censo previo, (4 C. pipiens hasta alcanzar la suma de δ A. aegypti y δ C. pipiens del censo previo y (5 A. aegypti y C. pipiens hasta δ A. aegypti y δ C. pipiens del censo previo. Las tres variables medidas fueron afectadas por los tratamientos, excepto la supervivencia y la biomasa producida por C. pipiens. Aedes aegypti fue más alterada por la competencia intraespecífica que por la competencia interespecífica. En C. pipiens, la competencia interespecífica superó en sus efectos a la competencia intraespecífica. Existió asimetría competitiva, ya que C. pipiens fue más afectada por A. aegypti que lo contrario.
Osório, Hugo Costa; Zé-Zé, Líbia; Alves, Maria João
The host blood-feeding patterns of mosquito vectors affects the likelihood of human exposure to zoonotic pathogens, including West Nile Virus (family Flaviviridae, genus Flavivirus, WNV). In Portugal, data are unavailable regarding the blood-feeding habits of common mosquito species, including Culex pipiens L., considered the primary vector of WNV to humans. The sources of bloodmeals in 203 blood-fed mosquitoes of nine species collected from June 2007 to November 2010 in 34 Portuguese counties were analyzed by sequencing cytochrome-b partial fragments. Cx. pipiens was the most common species collected and successfully analyzed (n = 135/78). In addition, blood-fed females of the following species were analyzed: Ochlerotatus caspius Pallas (n = 20), Culex theileri Theobald (n = 16), Anopheles maculipennis s.l. Meigen (n = 10), Culiseta longiareolata Macquart (n = 7), Aedes aegypti L. (n = 6), Culex perexiguus Theobald (n = 3), Culiseta annulata Schrank (n = 3), and Ochlerotatus detritus Haliday (n = 3). The Cx. pipiens mosquitoes fed predominantly on birds (n = 55/78, 70.5%), with a high diversity of avian species used as hosts, although human blood was identified in 18 specimens (18/78, 23.1%). No significant differences were found between the host-feeding patterns of blood-fed Cx. pipiens collected in residential and nonresidential habitats. The occurrence of human derived blood meals and the presence of a mix avian-human bloodmeal accordingly suggest this species as a potential vector of WNV. Therefore, in Portugal, Cx. pipiens may play a role both in the avian-to-avian enzootic WNV cycle and in the avian-to-mammal transmission. In this context, the identity of Cx. pipiens (considering the forms molestus and pipiens) and the potential consequence on feeding behavior and WNV transmission are discussed.
Boothe, Emily; Medeiros, Matthew C I; Kitron, Uriel D; Brawn, Jeffrey D; Ruiz, Marilyn O; Goldberg, Tony L; Walker, Edward D; Hamer, Gabriel L
Multiple mosquito-borne parasites cocirculate in nature and potentially interact. To understand the community of parasites cocirculating with West Nile virus (WNV), we screened the bloodmeal content of Culex pipiens L. mosquitoes for three common types of hemoparasites. Blood-fed Cx. pipiens were collected from a WNV-epidemic area in suburban Chicago, IL, from May to September 2005 through 2010. DNA was extracted from dissected abdomens and subject to PCR and direct sequencing to identify the vertebrate host. RNA was extracted from the head or thorax and screened for WNV using quantitative reverse transcriptase PCR. Seventy-nine engorged females with avian host origin were screened using PCR and amplicon sequencing for filarioid nematodes, Haemosporida, and trypanosomatids. Filarioid nematodes were identified in 3.8% of the blooded abdomens, Plasmodium sp. in 8.9%, Haemoproteus in 31.6%, and Trypanosoma sp. in 6.3%. The sequences from these hemoparasite lineages were highly similar to sequences from birds in prior studies in suburban Chicago. Overall, 50.6% of blood-fed Culex pipiens contained hemoparasite DNA in their abdomen, presumably from current or prior bloodmeals. Additionally, we detected hemoparasite DNA in the blooded abdomen of three of 10 Cx. pipiens infected with WNV. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Muñnoz, Joaquin; Eritja, Roger; Alcaide, Miguel; Montalvo, Tomás; Soriguer, Ramón C; Figuerola, Jordi
The feeding patterns of haematophagous arthropods are of major importance in the amplification and transmission of infectious disease agents to vertebrate hosts, including humans. The establishment of new vector populations in nonnative range might alter transmission networks. The Asian tiger mosquito Aedes albopictus (Skuse) represents an example of how an invasive species can alter the risk of viral transmission to humans. Blood meal molecular identification from two sympatric mosquito species (the invasive Ae. albopictus and the native Culex pipiens) was carried out by polymerase chain reaction-based methods. Samples were collected in Barcelona metropolitan area, Spain, from June to October 2009 as part of a monitoring-control program. Blood meals were identified to the species level in 30 Ae. albopictus and 43 Cx. pipiens. Ae. albopictus acquired blood exclusively from human hosts (100%), whereas Cx. pipiens fed on a diversity of avian and mammalian hosts, including 35.7% of blood meals from humans. Based on mosquito diet, our results suggest that the Ae. albopictus invasion in Spain might increase the risk of virus transmission to humans and could support local outbreaks of imported tropical viruses such as dengue and chikungunya. However, in the studied area, the presence of this invasive species would have a negligible effect on the transmission of zoonotic agents such as West Nile virus. However, Cx. pipiens could amplify and transmit West Nile virus, but avian contribution to its diet was lower than that reported in North America. Feeding patterns of these mosquito species may help to understand the flavivirus outbreaks recently reported in southwestern Europe.
Johnson, Brian J; Fonseca, Dina M
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.
Efectos de la competencia larval en los mosquitos de contenedores artificiales, Aedes aegypti y Culex pipiens (Diptera: Culicidae en condiciones semi-controladas Effects of larval competition between the container mosquitoes, Aedes aegypti and Culex pipiens (Diptera: Culicidae in semi-controlled conditions
Full Text Available Las larvas de los mosquitos Aedes aegypti (Linneo y Culex pipiens Linneo pueden criar conjuntamente en pequeños contenedores artificiales de agua, se genera así una competencia interespecífica y/o intraespecífica. El objetivo de este trabajo fue comparar la magnitud relativa de la competencia intra e interespecífica en A. aegypti y C. pipiens, generada durante el desarrollo larval en contenedores artifi ciales. Las variables medidas como respuesta fueron la supervivencia y el tiempo de desarrollo larval, y la biomasa total producida en estado de pupa. Se criaron larvas de ambos mosquitos en neumáticos de automóvil con agua declorinada y hojarasca. Se introdujeron larvas recién eclosionadas de acuerdo a la densidad (5 estimada según un censo previo de A. aegypti y C. pipiens. Serealizaron los siguientes tratamientos agregando larvas de: (1 A. aegypti hasta alcanzar δ A. aegypti determinada según el censo previo, (2 C. pipiens hasta δ C. pipiens del censo previo, (3 A. aegypti hasta alcanzar la suma de δ A. aegypti y δ C. pipiens del censo previo, (4 C. pipiens hasta alcanzar la suma de δ A. aegypti y δ C. pipiens del censo previo y (5 A. aegypti y C. pipiens hasta δ A. aegypti y δ C. pipiens del censo previo. Las tres variables medidas fueron afectadas por los tratamientos, excepto la supervivencia y la biomasa producida por C. pipiens. Aedes aegypti fue más alterada por la competencia intraespecífica que por la competencia interespecífica. En C. pipiens, la competencia interespecífica superó en sus efectos a la competencia intraespecífica. Existió asimetría competitiva, ya que C. pipiens fue más afectada por A. aegypti que lo contrario.Larvae of Aedes aegypti (Linneo and Culex pipiens Linneo may develop together in small artificial water containers, promoting inter- and/or intra-specific competition. Our aim was to compare the relative importance of interspecific and intraspecific competition in both species during
Richards, Stephanie L; Mores, Christopher N; Lord, Cynthia C; Tabachnick, Walter J
Culex pipiens quinquefasciatus Say mosquitoes from a laboratory colony were exposed to artificial blood meals containing West Nile virus (WNV) and held at incubation temperatures approximating average daily temperatures that occur during Florida arboviral periods. Mosquitoes fed blood meals containing 6.2 logs plaque-forming units (pfu) WNV/mL and held at 25 degrees C, 28 degrees C, or 30 degrees C for 13 days exhibited significantly different rates of infection (30%, 52%, 93%) and dissemination (33%, 22%, 81%) across temperatures. In a separate experiment, Cx. p. quinquefasciatus mosquitoes were provided artificial blood meals with graded doses of WNV from 3.7 to 5.8 logs pfu/mL and maintained at 28 degrees C for 13 days. Rates of infection increased as a function of virus dose, but neither body titers nor dissemination rates were significantly different for mosquitoes that were infected by ingesting different amounts of WNV. Our findings indicate that efficiency of WNV infection and dissemination, and thereby transmission, in Cx. p. quinquefasciatus populations similar to our tested colony may also be diminished when fed blood meals containing less than 5.8 logs pfu WNV/mL and when environmental temperature falls below 30 degrees C. The relationship between the infection rate and dissemination rate changed at different temperatures. This relationship is likely complex and dependent on diverse interactions between factors such as incubation temperature and viremia, which should also be assessed for field populations.
Fouad; El-Akhal; Abdelhakim; El; Ouali; Lalami; Yassine; Ez; Zoubi; Hassane; Greche; Raja; Guemmouh
Objective:To evaluate the larvicidal activity of essential oil of Origanum mtijoruna（Lamiaceae）cultivated in Morocco against Culex pipiens（Diptera:Culicidae）.Methods:The analysis and the identification of the various constituents of essential oil were carried out by gas chromatography coupled with mass spectrometry.Biological test was performed according to a standard methodology inspired by the World Health Organization protocol with slight modification.Results:This oil mainly consisted of monoterpene and sesquiterpenes.The majority compounds are 4-terpinene（28.96%）,y-terpinene（18.57%）,α-terpinene（12.72%） and sabinene（8.02%）.The lethal concentrations(LC50 and LC90) measured for the essential oil Origanum majorana,were respectively of the order of 258.71 mg/L and 580.49 mg/L.Conclusions:The results could be useful in search for newer,safer,and more effective natural larvicidal agents.
Yoshii, Manabu; Mine, Mariko; Kurokawa, Kenji; Oda, Tsutomu; Kato, Katsutomo; Ogawa, Yasunori; Eshita, Yuuki; Uchida, Keikichi
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.
Sampling a cosmopolitan mosquito (Diptera: Culicidae) species throughout its range is logistically challenging and extremely resource intensive. Mosquito control programmes and regional networks operate at the local level and often conduct sampling activities across much of North America. A method f...
Diversity of Wolbachia pipientis strain wPip in a genetically admixtured, above-ground Culex pipiens (Diptera: Culicidae) population: association with form molestus ancestry and host selection patterns.
Morningstar, Rebecca J; Hamer, Gabriel L; Goldberg, Tony L; Huang, Shaoming; Andreadis, Theodore G; Walker, Edward D
Analysis of molecular genetic diversity in nine marker regions of five genes within the bacteriophage WO genomic region revealed high diversity of the Wolbachia pipentis strain wPip in a population of Culex pipiens L. sampled in metropolitan Chicago, IL. From 166 blood fed females, 50 distinct genetic profiles of wPip were identified. Rarefaction analysis suggested a maximum of 110 profiles out of a possible 512 predicted by combinations of the nine markers. A rank-abundance curve showed that few strains were common and most were rare. Multiple regression showed that markers associated with gene Gp2d, encoding a partial putative capsid protein, were significantly associated with ancestry of individuals either to form molestus or form pipiens, as determined by prior microsatellite allele frequency analysis. None of the other eight markers was associated with ancestry to either form, nor to ancestry to Cx. quinquefasciatus Say. Logistic regression of host choice (mammal vs. avian) as determined by bloodmeal analysis revealed that significantly fewer individuals that had fed on mammals had the Gp9a genetic marker (58.5%) compared with avian-fed individuals (88.1%). These data suggest that certain wPip molecular genetic types are associated with genetic admixturing in the Cx. pipiens complex of metropolitan Chicago, IL, and that the association extends to phenotypic variation related to host preference.
Tuno, N; Kohzu, A; Tayasu, I; Nakayama, T; Githeko, A; Yan, G
The population sizes of Anopheles gambiae Giles (Diptera: Culicidae) and Anopheles arabiensis Patton (Diptera: Culicidae) increase dramatically with the onset of the rainy season in sub-Saharan Africa, but the ecological mechanisms underlying the increases are not well understood. As a first step toward to understand, we investigated the proliferation of algae, the major food of mosquito larvae, in artificial fresh water bodies exposed to sunlight for a short period, and old water bodies exposed to sunlight for a long period, and the effects thereof on the development of these anopheline larvae. We found that an epizoic green algal species of the genus Rhopalosolen (Chlorophyta: Chlorophyceae) proliferated immediately after water freshly taken from a spring was placed in sunlight. This alga proliferated only briefly (for ~10 d) even if the water was repeatedly exposed to sunlight. However, various algal species were observed in water that remained under sunlight for 40 d or longer (i.e., in old water bodies). The growth performance of larvae was higher in sunlight-exposed (alga-rich) water than in shade-stored (alga-poor) water. Stable isotope analysis suggested that these two anopheline species fed on Rhopalosolen algae in fresh water bodies but hardly at all on other algae occurring in the old water bodies. We concluded that freshly formed ground water pools facilitate high production of anopheline species because of the proliferation of Rhopalosolen algae therein, and the increase in the number of such pools in the rainy season, followed by rapid increases in A. gambiae and A. arabiensis numbers. © The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: email@example.com.
Diptera: Culicidae). Rev. Bras. Entomol. 10: 169-187. 1962. Entomologia medica, vol. I. Parte Geral, Diptera, Anophelini. Faculdade de Higiene e...Ronderos. 1962. Mosquitos de la Re- Ortiz, I. 1968. Apuentes de entomologia medica: 10s mos- publica Argentina. I. Tribu Anophelini (Diptera - Culic
Lebl, Karin; Zittra, Carina; Silbermayr, Katja; Obwaller, Adelheid; Berer, Dominik; Brugger, Katharina; Walter, Melanie; Pinior, Beate; Fuehrer, Hans-Peter; Rubel, Franz
Mosquitoes (Diptera: Culicidae) are important vectors for a wide range of pathogenic organisms. As large parts of the human population in developed countries live in cities, the occurrence of vector-borne diseases in urban areas is of particular interest for epidemiologists and public health authorities. In this study, we investigated the mosquito occurrence in the city of Vienna, Austria, in order to estimate the risk of transmission of mosquito-borne diseases. Mosquitoes were captured using different sampling techniques at 17 sites in the city of Vienna. Species belonging to the Culex pipiens complex (78.8 %) were most abundant, followed by Coquillettidia richiardii (10.2 %), Anopheles plumbeus (5.4 %), Aedes vexans (3.8 %), and Ochlerotatus sticticus (0.7 %). Individuals of the Cx. pipiens complex were found at 80.2 % of the trap sites, while 58.8 % of the trap sites were positive for Cq. richiardii and Ae. vexans. Oc. sticticus was captured at 35.3 % of the sites, and An. plumbeus only at 23.5 % of the trap sites. Cx. pipiens complex is known to be a potent vector and pathogens like West Nile virus (WNV), Usutu virus (USUV), Tahyna virus (TAHV), Sindbis virus (SINV), Plasmodium sp., and Dirofilaria repens can be transmitted by this species. Cq. richiardii is a known vector species for Batai virus (BATV), SINV, TAHV, and WNV, while Ae. vexans can transmit TAHV, USUV, WNV, and Dirofilaria repens. An. plumbeus and Oc. sticticus seem to play only a minor role in the transmission of vector-borne diseases in Vienna. WNV, which is already wide-spread in Europe, is likely to be the highest threat in Vienna as it can be transmitted by several of the most common species, has already been shown to pose a higher risk in cities, and has the possibility to cause severe illness.
Zahirnia A H
Full Text Available Introduction: Insects as the largest category of arthropods include numerous groups and families that the most important of them belong to order Diptera, family Culicidae. Because of feeding on the human's blood, a number of species of this family have been known as responsible for the transmission of pathogens for many diseases such as malaria, filariasis, encephalitis, yellow fever and dengue fever in the world. Given that no research has been conducted to determine the fauna of existing mosquitoes in the city of Poldokhtar, Lorestan Province, the present study aimed to exactly determine the mosquitoes' fauna in this city to perform appropriate prevention measures. Methods: In this faunistic and cross-sectional descriptive study, four urban areas and four rural areas in four geographic directions in the city of Poldokhtar were determined. In each urban area, two places and in each designated rural area, four places including two human places and two animal places were selected. From the early of April 2015 to the early of January 2016, larvae, pupae and adult mosquitoes of the Culicidae family were collected. Sampling methods for larvae, pupae and mature were ladling, night catch, total and hand catch with an aspirator. Characteristics including the name of the collector, date of collection, code related to habitat, habitat status (permanent or temporary, type of vegetation cover, type of substrate, and the situation of sunlight were recorded in the related form. The samples were identified by resources and valid identification keys. The data were analyzed using the SPSS software version 19. Results: Totally, 5392 mosquito adults of the Culicidae family including 1818 mosquito adults and 3574 larvae in designated areas in the city as well as four rural areas were collected. The three genera Anopheles (21.9%, Culex (64.6%, and Culiseta (13.5% were diagnosed. Also, from three genera, 12 species were identified as follows: Culex theiler, Cx
Fonseca, Dina M.
Aedes japonicus japonicus (Theobald) (Diptera: Culicidae) has recently expanded beyond its native range of Japan and Korea into large parts of North America and Central Europe. Population genetic studies begun immediately after the species was detected in North America revealed genetically distinct introductions that subsequently merged, likely contributing to the successful expansion. Interactions, particularly in the larval stage, with other known disease vectors give this invasive subspecies the potential to influence local disease dynamics. Its successful invasion likely does not involve superior direct competitive abilities, but it is associated with the use of diverse larval habitats and a cold tolerance that allows an expanded seasonal activity range in temperate climates. We predict a continued but slower expansion of Ae. j. japonicus in North America and a continued rapid expansion into other areas as this mosquito will eventually be considered a permanent resident of much of North America, Europe, Asia, and parts of Hawaii. PMID:24397520
Full Text Available Foram feitas coletas de mosquito (Diptera: Culicidae na área do projeto de Colonização Pedro Peixoto, no Estado do Acre, Brasil. Obteve-se um total de 4.588 exemplares pertencentes a 53 espécies ou grupos. Salienta-se a ocorrência de Anopheles (Nyssorhynchus oswaldoi.Mosquito (Diptera: Culicidae collections were made on the Pedro Peixoto Colonization Project in the State of Acre, Brazil. Four thousand, five hundred and eighty-eight (4,588 specimens were collected and fifty-three (53 species or group recognised. The occurrence of Anopheles (Nyssorhynchus oswaldoi is given special emphasis.
Neiva & Pinto) (Diptera: Culicidae) Maria Anice Mureb Sallum/+, Richard C Wilkerson* Núcleo de Pesquisa Taxonômica e Sistemática em Entomologia ...Taxonômica e Sistemática em Entomologia Médica, Universidade de São Paulo, São Paulo. The following specimens were used for setal counts and measurements (the
Full Text Available The present paper reports the preliminary results of the survey of the mosquito fauna (Diptera: Culicidae in Maliuc - Mila 26 area, in 2006. A number of 1,255 mosquitoes, belonging to 14 species have beencaptured in three investigation sites. The results of the data-analysis were used for drawing up the annual dynamics of the various mosquito species from a specific location in Maliuc - Mila 26 area for the period April –September.
Rosa Sá Gomes Hutchings
Full Text Available With 312 trap-hours of sampling effort, 1554 specimens of Culicidae (Diptera were collected, using CDC and Malaise traps, in nine different locations along the Juami River, within the Juami-Japurá Ecological Station, Amazonas State, Brazil. A list of mosquito species with 54 taxa is presented, which includes three new distributional records for the state of Amazonas. The species found belong to the genera Anopheles, Aedeomyia, Aedes, Psorophora, Culex, Coquillettidia, Sabethes, Wyeomyia and Uranotaenia.
Toxicity of Thiophenes from Echinops transiliensis (Asteraceae) against Aedes aegypti (Diptera: Culicidae) Larvae by Hiroshi Nakano*a)b)c), Abbas...larvicides against Aedes aegypti. Structural differences among compounds 3, 5, and 8 consisted in differing AcO and OH groups attached to C(3’’) and C(4...serious human diseases including malaria, Japanese encephalitis, yellow fever, dengue, and filariasis. The urban-adapted Aedes aegypti mosquito has become
Mosquitos no litoral paranaense. I - Idade fisioldgica de no Parque National da Serra dos Orgaos, Anopheles cruzii (Diptera, Culicidae). Arq. Estado do...no Parque National da Peryassii, A.G. 1908. OS culicideos do Brazil. Serra dos Grgaos, Estado do Rio de Janeiro, Inst. de Manguinhos, Rio de Janeiro...Kerteszia no litoral Guimar%es, A.E. and V.N.M. Victoria. 1986. do estado de Santa Catarina. Rev. Bras. Mosquitos no Parque National da Serra dos
van den Hurk, Andrew F; Johnson, Petrina H; Hall-Mendelin, Sonja; Northill, Judy A; Simmons, Russell J; Jansen, Cassie C; Frances, Stephen P; Smith, Greg A; Ritchie, Scott A
Biological transmission of arboviruses to a vertebrate host occurs when virions are expelled along with saliva during blood feeding by a hematophagous arthropod. We undertook experiments to determine whether mosquitoes expectorate flaviviruses in their saliva while sugar feeding. Batches of Culex annulirostris Skuse and Culex gelidus Theobald (Diptera: Culicidae) were orally infected with Japanese encephalitis (family Flaviviridae, genus Flavivirus, JEV), Kunjin (family Flaviviridae, genus Flavivirus, KUNV; a subtype of West Nile virus), and Murray Valley encephalitis (family Flaviviridae, genus Flavivirus, MVEV) viruses. After a 7-d extrinsic incubation, these mosquitoes were offered sucrose meals via cotton pledgets, which were removed daily and processed for viral RNA by using real-time TaqMan reverse transcriptase-polymerase chain reaction (RT-PCR) assays. JEV, MVEV, and KUNV RNA was detected in all pledgets removed from batches of Cx. gelidus on days 7-14 postexposure. In contrast, detection rates were variable for Cx. annulirostris, with KUNV detected in 0.3 M sucrose pledgets on all days postexposure, and JEV and MVEV detected on 57 and 50% of days postexposure, respectively. Higher concentrations of sucrose in the pledget did not increase virus detection rates. When individual JEV-infected Cx. gelidus were exposed to the sucrose pledget, 73% of mosquitoes expectorated virus with titers that were detectable by TaqMan RT-PCR. These results clearly show that flaviviruses are expectorated by infected mosquitoes during the process of sugar feeding on artificial pledgets. Potential applications of the method for arboviral bioassays and field surveillance are discussed.
The Subgenus Stegomyia of Aedes in the Afrotropical Region. 2. The Dendrophilus Group of Species (Diptera: Culicidae) (Contributions of the American Entomological Institute. Volume 29, Number 4, 1997)
or reservoirs of eight viruses , six of which cause human illness (Chikungunya, dengue 1 and 2, Dugbe, Rift Valley fever, yellow fever and Zika ...suggested that Ae. deboeri may be the jungle vector of the yellow fever virus in Langata. A edes Aedes Aedes Aedes (Stegomyia) demeilloni Edwards... Aedes (Stegomyia) Iedgeri (Diptera: Culicidae). Mosq. Syst. 13: 92-113. Aedes (Stegomyia) bromeliae (Diptera: Culicidae), the yellow fever virus
Full Text Available Foram feitas coletas de mosquito (Diptera: Culicidae na área do projeto de Colonização Pedro Peixoto, no Estado do Acre, Brasil. Obteve-se um total de 4.588 exemplares pertencentes a 53 espécies ou grupos. Salienta-se a ocorrência de Anopheles (Nyssorhynchus oswaldoi.
Qiu, Y.T.; Smallegange, R.C.; Braak, ter C.J.F.; Spitzen, J.; Loon, van J.J.A.; Jawara, M.; Milligan, P.; Galimard, A.M.S.; Beek, van T.A.; Knols, B.G.J.; Takken, W.
Chemical cues play an important role in the host-seeking behavior of blood-feeding mosquitoes (Diptera: Culicidae). A field study was carried out in The Gambia to investigate the effects of human odor or synthetic odor blends on the attraction of mosquitoes. MM-X traps baited with 16 odor blends to
Aedes albopictus Skuse (Diptera: Culicidae) was tested for resistance to permethrin, bifenthrin, and malathion using Centers for Disease Control and Prevention (CDC) bottle bioassays and topical toxicology assays on adults and larval bioassays. Eggs were collected from 3 locations across St. Johns C...
Full Text Available Foram feitas coletas de mosquito (Diptera: Culicidae na área do projeto de Colonização Pedro Peixoto, no Estado do Acre, Brasil. Obteve-se um total de 4.588 exemplares pertencentes a 53 espécies ou grupos. Salienta-se a ocorrência de Anopheles (Nyssorhynchus oswaldoi.
104. Brunhes, J. 1977a. Les moustiques de l’archipel des Comores I. - Inventaire, &partition et description de quatre esptces ou sous-espscies...nouvelles. Cah. O.R.S.T.O.M. Ser. Entomol. Med. Parasitol. 15:131-152. Brunhes, J. 1977b. Les moustiques de l’archipel des Comores 11. - Description de...Dieng. 1978. Aedes (Stegomyia) neoafricanus un nouvelle espzcie de moustique capture’e au Sgne’gal Oriental (Diptera: Culicidae), Cah. O.R.S.T.O.M
de Souza, A S; Couri, M S; Florindo, L
The effects of industrial anthropization on species composition and community diversity of Culicidae (Diptera) were studied in a mangrove area impacted by industrial activities as compared to a preserved area, both around Guanabara Bay in the state of Rio de Janeiro, Brazil. Diversity, equitability, and species richness in Culicidae community differed between the studied areas. Indicator species analysis and correspondence analysis were carried out and indicated that the Sabethini, especially Wyeomyia (Phoniomyia) theobaldi Lane, Wyeomyia (Phoniomyia) fuscipes (Edwards), and a non-identified species of Wyeomyia sp. were associated to the preserved area, whereas Aedes taeniorhynchus Wiedemann and Aedes scapularis (Rondani) to the impacted area.
Chan, Hiang Hao; Zairi, Jaal
Insecticide resistance has become a serious issue in vector management programs. Information on insecticidal resistance and its associated mechanisms is important for successful insecticide resistance management. The selection of a colony of permethrin-resistant Aedes albopictus (Skuse) (Diptera: Culicidae), originating from Penang Island, Malaysia, yielded high larval-specific resistance to permethrin and cross-resistance to deltamethrin. Synergism assays showed that the major mechanism underlying this resistance involves cytochrome P450 monooxygenase. The resistance is autosomal, polygenically inherited and incompletely dominant (D = 0.26). Resistant larvae were reared under different conditions to assess the fitness costs. Under high larval density, larval development time of the resistant SGI strain was significantly longer than the susceptible VCRU strain. In both high- and low-density conditions SGI showed a lower rate of emergence and survival compared with the VCRU strain. Resistant larvae were more susceptible to predation by Toxorhynchites splendens (Wiedemann) (Diptera: Culicidae) larvae. The body size of SGI females reared under high-density conditions was larger compared with females of the susceptible strain. SGI females survived longer when starved than did VCRU females. The energy reserve upon eclosion was positively correlated with the size of the adults.
Mário Luís Pessôa Guedes
Full Text Available Mosquito community composition in dynamic landscapes from the Atlantic Forest biome (Diptera, Culicidae. Considering that some species of Culicidae are vectors of pathogens, both the knowledge of the diversity of the mosquito fauna and how some environment factors influence in it, are important subjects. In order to address the composition of Culicidae species in a forest reserve in southern Atlantic Forest, we compared biotic and abiotic environmental determinants and how they were associated with the occurrence of species between sunset and sunrise. The level of conservation of the area was also considered. The investigation was carried out at Reserva Natural do Morro da Mina, in Antonina, state of Paraná, Brazil. We performed sixteen mosquito collections employing Shannon traps at three-hour intervals, from July 2008 to June 2009. The characterization of the area was determined using ecological indices of diversity, evenness, dominance and similarity. We compared the frequency of specimens with abiotic variables, i.e., temperature, relative humidity and pluviosity. Seven thousand four hundred ten mosquito females were captured. They belong to 48 species of 12 genera. The most abundant genera were Anopheles, Culex, Coquillettidia, Aedes and Runchomyia. Among the species, the most abundant was Anopheles cruzii, the primary vector of Plasmodium spp. in the Atlantic Forest. Results of the analyses showed that the abiotic variables we tested did not influence the occurrence of species, although certain values suggested that there was an optimum range for the occurrence of culicid species. It was possible to detect the presence of species of Culicidae with different epidemiologic profiles and habitat preference.
Identification and transcription profiling of NDUFS8 in Aedes taeniorhynchus (Diptera: Culicidae): developmental regulation and environmental response...7205 Email firstname.lastname@example.org Abstract: The cDNA of a NADH dehydrogenase-ubiquinone Fe-S protein 8 subunit (NDUFS8) gene from Aedes (Ochlerotatus...information useful for developing dsRNA pesticide for mosquito control. Keywords: Aedes taeniorhynchus, AetNDUFS8, mRNA expression, development
Govindarajan, M.; Rajeswary, M.; Sivakumar, R.
Background & objectives: In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticide, this study was undertaken to assess the larvicidal and ovicidal potential of the crude hexane, benzene, chloroform, ethyl acetate and methanol solvent extracts from the medicinal plant Pithecellobium dulce against the mosquito vectors, Anopheles stephensi and Aedes aegypti (Diptera: Culicidae). Methods: Larvicidal activity of P. dulce plant...
Vaughan, Jefferson A; Bell, Jeffrey A; Turell, Michael J; Chadee, Dave D
When virus and microfilariae are ingested concurrently by a mosquito, microfilariae (mf) may penetrate the mosquito midgut and introduce virus directly into the mosquito hemocoel, allowing mosquitoes to become infectious much sooner than normal and enhancing transmission of viruses by mosquitoes. Mansonella ozzardi (Manson) is a benign filarial nematode parasite of humans in Latin America and is transmitted by black flies (Diptera: Simuliidae) and biting midges (Diptera: Ceratopogonidae). Because M. ozzardi and dengue are sympatric, we wanted to know whether M. ozzardi mf had the ability to penetrate the midgut of Aedes aegypti (L.) (Diptera: Culicidae) and thus play a potential role in the enhancement of dengue transmission. To test this, the F1 progeny from locally collected Ae. aegypti were fed on M. ozzardi-infected human males in an endemic village in northern Trinidad. Mosquitoes were dissected at various times after feeding and examined for mf in the midguts and thoraces. Microfilariae penetrated the midguts of 43% of 63 mosquitoes that ingested mf. Overall, 11% of mf penetrated the midgut by 17 h after being ingested. The intensity of midgut penetration was positively correlated to the numbers of mf ingested. Because midgut penetration is a key requirement for mf enhancement to occur, the potential exists that M. ozzardi could be involved in the enhancement of dengue virus transmission.
Brasileira de Malariologia e Doenças Tropicais 16, 329–348. Forattini, O.P. (1962) Entomologia médica. Parte geral, Diptera, Anophelini. Vol.1...Estado do Espírito Santo, Brasil. Revista Brasileira de Entomologia 52, 671–673. Schultz, J., Müller, T., Achtziger, M., Seibel, P.N., Dandekar, T
Qualls, Whitney A; Day, Jonathan F; Xue, Rui-De; Bowers, Doria F
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.
Barnard, Donald R; Xue, Rui-De; Rotstein, Margaret A; Becnel, James J
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.
Kalan, Katja; Ivovic, Vladimir; Glasnovic, Peter; Buzan, Elena
In Slovenia, two invasive mosquito species are present, Aedes albopictus (Skuse, 1895) (Diptera: Culicidae) and Aedes japonicus (Theobald, 1901) (Diptera: Culicidae). In this study, we examined their actual distribution and suitable habitats for new colonizations. Data from survey of species presence in 2013 and 2015, bioclimatic variables and altitude were used for the construction of predictive maps. We produced various models in Maxent software and tested two bioclimatic variable sets, WorldClim and CHELSA. For the variable selection of A. albopictus modeling we used statistical and expert knowledge-based approach, whereas for A. j. japonicus we used only a statistically based approach. The best performing models for both species were chosen according to AIC score-based evaluation. In 2 yr of sampling, A. albopictus was largely confined to the western half of Slovenia, whereas A. j. japonicus spread significantly and can be considered as an established species in a large part of the country. Comparison of models with WorldClim and CHELSA variables for both species showed models with CHELSA variables as a better tool for prediction. Finally, we validated the models performance in predicting distribution of species according to collected field data. Our study confirms that both species are co-occurring and are sympatric in a large part of the country area. The tested models could be used for future prevention of invasive mosquitoes spreading in other countries with similar bioclimatic conditions. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: email@example.com.
Mosquitoes transmit pathogens that cause millions of human deaths each year. Dengue virus is transmitted to humans in tropical and subtropical areas by Aedes aegypti (Diptera: Culicidae). The use of synthetic insecticides to control this mosquito is accompanied by high operational costs and adverse...
Versteirt, V; Boyer, S; Damiens, D; De Clercq, E M; Dekoninck, W; Ducheyne, E; Grootaert, P; Garros, C; Hance, T; Hendrickx, G; Coosemans, M; Van Bortel, W
To advance our restricted knowledge on mosquito biodiversity and distribution in Belgium, a national inventory started in 2007 (MODIRISK) based on a random selection of 936 collection points in three main environmental types: urban, rural and natural areas. Additionally, 64 sites were selected because of the risk of importing a vector or pathogen in these sites. Each site was sampled once between May and October 2007 and once in 2008 using Mosquito Magnet Liberty Plus traps. Diversity in pre-defined habitat types was calculated using three indices. The association between species and environmental types was assessed using a correspondence analysis. Twenty-three mosquito species belonging to traditionally recognized genera were found, including 21 indigenous and two exotic species. Highest species diversity (Simpson 0.765) and species richness (20 species) was observed in natural areas, although urban sites scored also well (Simpson 0.476, 16 species). Four clusters could be distinguished based on the correspondence analysis. The first one is related to human modified landscapes (such as urban, rural and industrial sites). A second is composed of species not associated with a specific habitat type, including the now widely distributed Anopheles plumbeus. A third group includes species commonly found in restored natural or bird migration areas, and a fourth cluster is composed of forest species. Outcomes of this study demonstrate the effectiveness of the designed sampling scheme and support the choice of the trap type. Obtained results of this first country-wide inventory of the Culicidae in Belgium may serve as a basis for risk assessment of emerging mosquito-borne diseases.
Chen, Kai; Wang, Yan; Li, Xiang-Yu; Peng, Heng; Ma, Ya-Jun
Anopheles sinensis (Diptera: Culicidae) is a primary vector of Plasmodium vivax and Brugia malayi in most regions of China. In addition, its phylogenetic relationship with the cryptic species of the Hyrcanus Group is complex and remains unresolved. Mitochondrial genome sequences are widely used as molecular markers for phylogenetic studies of mosquito species complexes, of which mitochondrial genome data of An. sinensis is not available. An. sinensis samples was collected from Shandong, China, and identified by molecular marker. Genomic DNA was extracted, followed by the Illumina sequencing. Two complete mitochondrial genomes were assembled and annotated using the mitochondrial genome of An. gambiae as reference. The mitochondrial genomes sequences of the 28 known Anopheles species were aligned and reconstructed phylogenetic tree by Maximum Likelihood (ML) method. The length of complete mitochondrial genomes of An. sinensis was 15,076 bp and 15,138 bp, consisting of 13 protein-coding genes, 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes, and an AT-rich control region. As in other insects, most mitochondrial genes are encoded on the J strand, except for ND5, ND4, ND4L, ND1, two rRNA and eight tRNA genes, which are encoded on the N strand. The bootstrap value was set as 1000 in ML analyses. The topologies restored phylogenetic affinity within subfamily Anophelinae. The ML tree showed four major clades, corresponding to the subgenera Cellia, Anopheles, Nyssorhynchus and Kerteszia of the genus Anopheles. The complete mitochondrial genomes of An. sinensis were obtained. The number, order and transcription direction of An. sinensis mitochondrial genes were the same as in other species of family Culicidae.
Trari, Bouchra; Dakki, Mohamed; Harbach, Ralph E
An updated checklist of the mosquito species (Diptera: Culicidae) recorded in Morocco from 1916 to 2016 is provided, including synonyms and synonymous usage for each species. Forty-three species belonging to seven genera are recorded so far: Anopheles (9), Aedes (12) Coquillettidia (2), Culex (12), Culiseta (5), Orthopodomyia (1) and Uranotaenia (2). Traditional and equivalent names in the polyphyletic concept of Aedes are provided for the aedine species. The historical importance and current potential threat of mosquitoes to human health in Morocco is reviewed. © 2017 The Society for Vector Ecology.
Santos,Cleandson Ferreira; Borges,Magno
AbstractINTRODUCTION: This study evaluated the effects of cattle removal on the Culicidae mosquito community structure in a tropical dry forest in Brazil.METHODS: Culicidae were collected during dry and wet seasons in cattle presence and absence between August 2008 and October 2010 and assessed using multivariate statistical models.RESULTS: Cattle removal did not significantly alter Culicidae species richness and abundance. However, alterations were noted in Culicidae community composition.CO...
Dunbar, Mike W; Bachmann, Amanda; Varenhorst, Adam J
Mosquito abatement programs in Midwestern communities frequently exist within landscapes dominated by agriculture. Although separately managed, both agricultural pests and mosquitoes are targeted by similar classes of insecticides. As a result, there is the potential for unintended insecticide exposure to mosquito populations from agricultural pest management. To determine the impact that agricultural management practices have on mosquito insecticide susceptibility we compared the mortality of Aedes vexans (Meigen; Diptera: Culicidae) between populations sampled from locations with and without mosquito abatement in South Dakota, a region dominated by agricultural production. Collection locations were either within towns with mosquito abatement programs (n = 2; Brookings and Sioux Falls, SD) or located > 16 km from towns with mosquito abatement programs (n = 2; areas near Harrold and Willow Lake, SD). WHO bioassays were used to test susceptibly of adults to differing insecticide classes relative to their respective controls; 1) an organochlorine (dieldrin 4%), 2) an organophosphate (malathion 5%), and 3) a pyrethroid (lambda-cyhalothrin 0.05%). Corrected mortality did not significantly differ between locations with or without abatement; however, when locations were analized by proportion of developed land within the surrounding landscape pyrethroid mortality was significantly lower where crop production dominated the surrounding landscape and mosquito abatement was present. These data suggest that agricultural pest management may incidentally contribute to reduced mosquito susceptibility where overlap between agricultural pest management and mosquito abatement exists. Decoupling insecticide classes used by both agricultural and public health pest management programs may be necessary to ensure continued efficacy of pest management tools.
Berec, Ludĕk; Gelbic, Ivan; Sebesta, Oldrich
An understanding of how climate variables drive seasonal dynamics of mosquito populations is critical to mitigating negative impacts of potential outbreaks, including both nuisance effects and risk of mosquito-borne infectious disease. Here, we identify climate variables most affecting seasonal dynamics of two major floodwater mosquitoes, Aedes vexans (Meigen, 1830) and Aedes sticticus (Meigen, 1838) (Diptera: Culicidae), along the lower courses of the Dyje River, at the border between the Czech Republic and Austria. Monthly trap counts of both floodwater mosquitoes varied both across sites and years. Despite this variability, both models used to fit the observed data at all sites (and especially that for Ae. sticticus) and site-specific models fitted the observed data quite well. The most important climate variables we identified-temperature and especially flooding-were driving seasonal dynamics of both Aedes species. We suggest that flooding determines seasonal peaks in the monthly mosquito trap counts while temperature modulates seasonality in these counts. Hence, floodwater mosquitoes indeed appear worthy of their name. Moreover, the climate variables we considered for modeling were able reasonably to predict mosquito trap counts in the month ahead. Our study can help in planning flood management; timely notification of people, given that these mosquitoes are a real nuisance in this region; public health policy management to mitigate risk from such mosquito-borne diseases as that caused in humans by the Tahyna virus; and anticipating negative consequences of climate change, which are expected only to worsen unless floods, or the mosquitoes themselves, are satisfactorily managed.
Yamamoto, Daisuke S; Hatakeyama, Masatsugu; Matsuoka, Hiroyuki
In the past decade, many transgenic lines of mosquitoes have been generated and analyzed, whereas the maintenance of a large number of transgenic lines requires a great deal of effort and cost. In vitro fertilization by an injection of cryopreserved sperm into eggs has been proven to be effective for the maintenance of strains in mammals. The technique of artificial egg activation is a prerequisite for the establishment of in vitro fertilization by sperm injection. We demonstrated that artificial egg activation is feasible in the malaria vector mosquito, Anopheles stephensi (Diptera, Culicidae). Nearly 100% of eggs dissected from virgin females immersed in distilled water darkened, similar to normally oviposited fertilized eggs. It was revealed by the cytological examination of chromosomes that meiotic arrest was relieved in these eggs approximately 20 min after incubation in water. Biochemical examinations revealed that MAPK (mitogen-activated protein kinase)/ERK (extracellular signal-regulated protein kinase) and MEK (MAPK/ERK kinase) were dephosphorylated similar to that in fertilized eggs. These results indicate that dissected unfertilized eggs were activated in distilled water and started development. Injection of distilled water into body cavity of the virgin blood-fed females also induced activation of a portion of eggs in the ovaries. The technique of artificial egg activation is expected to contribute to the success of in vitro fertilization in A. stephensi.
Rosângela MR Barbosa
Full Text Available An ovitrap (BR-OVT based on physical and chemical stimuli for attracting gravid Culex quinquefasciatus (Diptera: Culicidae females was developed and evaluated under laboratory and field conditions. Attractants were assayed using alternative chamber bioassays prior to being used in the BR-OVT oviposition trap. A significant preference of gravid females for sites containing conspecific egg rafts was observed, as a response to the natural oviposition pheromone, as well as for sites treated with the synthetic pheromone erythro-6-acetoxy-5-hexadecanolide. Five- to 20-day old grass infusion was strongly attractive to gravid females for laying eggs. On the other hand, entomopathogenic Bacillus sphaericus (Bs did not influence the choice of an oviposition site when used in combination with grass infusion and can therefore be used as a larvicide in ovitraps. Results from field trials showed that the BR-OVT with grass infusion and with or without Bs works as a preferred oviposition site for Cx. quinquefasciatus. The BR-OVT was more effective for egg collection when placed indoors and comparison with the number of egg rafts laid in cesspits over 40 days indicates that this very simple ovitrap may be a useful tool for monitoring populations of the most important of the vectors of bancroftian filariasis.
Full Text Available ABSTRACT Near-infrared spectroscopy and microstructure of the scales of Sabethes (Sabethes albiprivus (Diptera: Culicidae. Sabethes (Sabethes albiprivus Theobald individuals vary considerably in size and color of the reflections of the scales on their thorax, abdomen, antepronotal lobes and occiput. The goal of this study was to investigate and to characterize the differences in the color of the scales among preserved specimens and to analyze the differences in the microstructures of the scales that cover their bodies using near-infrared spectroscopy, and to evaluate whether the latter is efficient in distinguishing the populations. A total of 201 adult females were analyzed for the characterization of color patterns. In addition, absorbance spectra and scanning electron microscope images were obtained from them. As a result of color analysis, two variations were identified, one represented by specimens with yellow or green scales and the other with blue or purple scales. The same two variations were corroborated using NIRS. Analysis of the microstructure of the scales lining the mesonotum, occiput and antepronotal lobes resulted in the same variations. The three methodologies, near-infrared spectroscopy, scanning electron microscopy and coloration of the reflections of the scales revealed two variations within Sa. albiprivus.
Naddaf, Saied Reza; Razavi, Mohammad Reza; Bahramali, Golnaz
Anopheles fluviatilis James (Diptera: Culicidae) is one of the known malaria vectors in south and southeastern Iran. Earlier ITS2 sequences analysis of specimens from Iran demonstrated only a single genotype that was identical to species Y in India, which is also the same as species T. We identified 2 haplotypes in the An. fluviatilis populations of Iran based on differences in nucleotide sequences of D3 domain of the 28S locus of ribosomal DNA (rDNA). Comparison of sequence data from 44 Iranian specimens with those publicly available in the Genbank database showed that all of the 28S-D3 sequences from Kazeroun and Khesht regions in Fars Province were identical to the database entry representing species U in India. In other regions, all the individuals showed heterozygosity at the single nucleotide position, which identifies species U and T. It is argued that the 2 species may co-occur in some regions and hybridize; however, the heterozygosity in the 28S-D3 locus was not reflected in ITS2 sequences and this locus for all individuals was identical to species T. This study shows that in a newly diverged species, like members of An. fluviatilis complex, a single molecular marker may not be sufficiently discriminatory to identify all the taxa over a vast geographical area. In addition, other molecular markers may provide more reliable information for species discrimination.
Alencar, Jeronimo; Silva, Júlia dos Santos; de Oliveira, Luis Claudio Motta; Marcondes, Carlos Brisola; Morone, Fernanda; Lorosa, Elias Seixas
Blood-feeding sources of Culex quinquefasciatus Say (Diptera: Culicidae) collected in the eastern region of the Brazilian state of Santa Catarina were analyzed by precipitin technique. One hundred fifty-four female mosquitoes collected by CDC traps in the Navegantes municipality 13-15 February 2005 reacted to one or more of eight antisera, including chicken, dog, goat, sheep, horse, opossum, human and rodent antisera. One hundred thirty-seven specimens (89%) reacted to only one source, and 17 (11%) specimens reacted to two sources. Among the 137 specimens reacting to only one source, reactions to rodent (50.4%), sheep (5.8%), chicken (5.1%), goat (5.1%), dog (2.2%), horse (3.6%), and human (3.6%) antisera were observed. The analyzed species demonstrated a high degree of opportunistic feeding behavior in relation to host preference. Results are compared with results from similar studies, and the low proportion of reactions to human antisera is discussed.
Full Text Available Objective: To evaluate the activity of spiromesifen against the most abundant and investigated mosquito species, Culiseta longiareolata Aitken, 1954 (Diptera, Culicidae. Methods: Culiseta longiareolata larvae were collected from untreated areas located at TÃ©bessa (Northeast Algeria. A commercial formulation of spiromesifen (OberonÂ® 240 SC was tested at different concentrations ranging between 238 and 1428Â Î¼g/L on newly molted fourth-instar larvae under standard laboratory conditions according to Word Health Organization recommendations. The effects were examined on the mortality, the morphometric measurements, two biomarkers (catalase and malondialdehyde, and the biochemical composition of larvae, respectively. Results: The compound exhibited insecticidal activity. Moreover, it disturbed growth and several morphological aberrations were observed. It also affected body volume, biomarkers and contents of carbohydrates, lipids and proteins. A marked effect on lipids and malondialdehyde was noted, confirming its primary mode of action on lipid synthesis. Conclusions: Spiromesifen appears less potent than other insecticides tested such as the insect growth disruptors. Keywords: Culiseta longiareolata, Spiromesifen, Toxicity, Biochemical composition, Biomarkers
João Antonio C. Zequi
Full Text Available Development of the immature stages of Culex (Culex saltanensis Dyar (Diptera, Culicidae under laboratory conditions. Culex (Culex saltanensis Dyar, 1928 is becoming frequent and abundant in natural and artificial breeding sites in urban and rural areas of Brazil. This study contributes to the knowledge of the biology of a Brazilian strain of C. saltanensis. The development of specimens reared individually or grouped was observed. The study was conducted at a constant temperature of 27 ± 2°C, 14L:10D photoperiod and 80 ± 5% relative humidity. The immature stages were observed every 6 hours until adult emergence, which occurred in 12.29 days among individually reared specimens and in 13.12 days among group-reared specimens. Egg rafts for the experiment were obtained from the laboratory and field. Eggs hatched at a rate of 97.48 ± 2.32%. More eggs per egg raft were obtained from the field than from the laboratory. Males from individually reared specimens emerged in 12.29 ± 1.11 days and females in 13.12 ± 1.58 days. The male-female ratio was 1:1. Larval survival rate was higher than 85% for larvae reared isolated and higher than 95% for group-reared larvae. The Culex saltanensis life cycle was completed within 12 to 14 days, where larval instars I and IV took the most time to develop and the pupae, the shortest.
Cleandson Ferreira Santos
Full Text Available AbstractINTRODUCTION: This study evaluated the effects of cattle removal on the Culicidae mosquito community structure in a tropical dry forest in Brazil.METHODS: Culicidae were collected during dry and wet seasons in cattle presence and absence between August 2008 and October 2010 and assessed using multivariate statistical models.RESULTS: Cattle removal did not significantly alter Culicidae species richness and abundance. However, alterations were noted in Culicidae community composition.CONCLUSIONS: This is the first study to evaluate the impact of cattle removal on Culicidae community structure in Brazil and demonstrates the importance of assessing ecological parameters such as community species composition.
Santos, Cleandson Ferreira; Borges, Magno
This study evaluated the effects of cattle removal on the Culicidae mosquito community structure in a tropical dry forest in Brazil. Culicidae were collected during dry and wet seasons in cattle presence and absence between August 2008 and October 2010 and assessed using multivariate statistical models. Cattle removal did not significantly alter Culicidae species richness and abundance. However, alterations were noted in Culicidae community composition. This is the first study to evaluate the impact of cattle removal on Culicidae community structure in Brazil and demonstrates the importance of assessing ecological parameters such as community species composition.
BANGOURA and A. LORAND. 1979. Isolements d’arbovirus au Senegal oriental a partir de moustiques (1972-1977) et notes sur l’epidemiologie des virus...Dengue 2 au Senegal oriental: Une poussee epizootioque en milieu selvatique; isolements du virus a partir de moustiques et d’un singe et...neoafticanus une nouvelle espece de moustique capturee au Senegal Oriental (Diptera: Culicidae). Cah. O.R.S.T.O.M. Ser. Entomol. Med. Parasitol. 16
Pathol. Exot. 53: 531-542. 1968. Contribution a I’etude des moustiques du Maroc (Diptera, Culicidae) six especes nouvelles pour le pays. Cah. ORSTOM...quelques moustiques du Maroc. Arch. inst. Pasteur Maroc 2: 361-365. 1957. Sur Culex torrentium Martini. Ann. Parasitol. Hum. Comp. 32: 438-442...De Grandpre, A.D. and D. D’E. De Charmoy 1900(1901). Les moustiques : anatomie et biologie. Contribution a I’etude des Culicides et principalement
major vector of malaria in China ; however, its vectorial capacity is unknown in the ROK. The other remaining four Anopheles species are not considered to...morphometry and morphology of Anopheles aconitus Form B and C eggs under scanning electron microscope. Revista do Instituto de Medicina Tropical de Sao Paulo...and its genetic identity with An. (Ano.) anthropophagus from China (Diptera: Culicidae). Zootaxa, 378, 1–14. RUEDA ET AL.40 · Zootaxa 2268 © 2009
Dengue Vector, Aedes aegypti (Diptera: Culicidae) JAMES F. HARWOOD,1,2 MUHAMMAD FAROOQ,1 ALEC G. RICHARDSON,1 CARL W. DOUD,1 JOHN L. PUTNAM,3 DANIEL E...vector, Aedes aegypti (L.), inside human habitations must be performed quickly and efÞciently to reduce the risk of transmission during dengue...immediate knockdown of vector populations that may lower the risk of infection and allow other suppression strategies to be implemented. KEY WORDS Aedes
Vadivalagan, Chithravel; Karthika, Pushparaj; Murugan, Kadarkarai; Panneerselvam, Chellasamy; Del Serrone, Paola; Benelli, Giovanni
Culex quinquefasciatus (Diptera: Culicidae) is a vector of many pathogens and parasites of humans, as well as domestic and wild animals. In urban and semi-urban Asian countries, Cx. quinquefasciatus is a main vector of nematodes causing lymphatic filariasis. In the African region, it vectors the Rift Valley fever virus, while in the USA it transmits West Nile, St. Louis encephalitis and Western equine encephalitis virus. In this study, DNA barcoding was used to explore the genetic variation of Cx. quinquefasciatus populations from 88 geographical regions. We presented a comprehensive approach analyzing the effectiveness of two gene markers, i.e. CO1 and 16S rRNA. The high threshold genetic divergence of CO1 (0.47%) gene was reported as an ideal marker for molecular identification of this mosquito vector. Furthermore, null substitutions were lower in CO1 if compared to 16S rRNA, which influenced its differentiating potential among Indian haplotypes. NJ tree was well supported with high branch values for CO1 gene than 16S rRNA, indicating ideal genetic differentiation among haplotypes. TCS haplotype network revealed 14 distinct clusters. The intra- and inter-population polymorphism were calculated among the global and Indian Cx. quinquefasciatus lineages. The genetic diversity index Tajima' D showed negative values for all the 4 intra-population clusters (G2-4, G10). Fu's FS showed negative value for G10 cluster, which was significant and indicated recent population expansion. However, the G2-G4 (i.e. Indian lineages) had positive values, suggesting a bottleneck effect. Overall, our research firstly shed light on the genetic differences among the haplotypes of Cx. quinquefasciatus species complex, adding basic knowledge to the molecular ecology of this important mosquito vector. Copyright © 2017 Elsevier B.V. All rights reserved.
Bisset, J A; Marín, R; Rodríguez, M M; Severson, D W; Ricardo, Y; French, L; Díaz, M; Pérez, O
Dengue (family Flaviridae, genus Flavivirus, DENV) and dengue hemorrhagic fever (DHF) are presently important public health problems in Costa Rica. The primary strategy for disease control is based on reducing population densities of the main mosquito vector Aedes aegypti (L.) (Diptera: Culicidae). This is heavily dependent on use of chemical insecticides, thus the development of resistance is a frequent threat to control program effectiveness. The objective of this study was to determine the levels of insecticide resistance and the metabolic resistance mechanisms involved in two Ae. aegypti strains collected from two provinces (Puntarenas and Limon) in Costa Rica. Bioassays with larvae were performed according to World Health Organization guidelines and resistance in adults was measured through standard bottle assays. The activities of beta-esterases, cytochrome P450 monooxygenases, and glutathione S-transferases (GST), were assayed through synergists and biochemical tests, wherein the threshold criteria for each enzyme was established using the susceptible Rockefeller strain. The results showed higher resistance levels to the organophosphate (OP) temephos and the pyrethroid deltamethrin in larvae. The efficacy of commercial formulations of temephos in controlling Ae. aegypti populations was 100% mortality up to 11 and 12 d posttreatment with daily water replacements in test containers. Temephos and deltamethrin resistance in larvae were associated with high esterase activity, but not to cytochrome P450 monooxygenase or GST activities. Adult mosquitoes were resistant to deltamethrin, and susceptible to bendiocarb, chlorpyrifos, and cypermethrin. Because temephos and deltamethrin resistance are emerging at the studied sites, alternative insecticides should be considered. The insecticides chlorpyrifos and cypermethrin could be good candidates to use as alternatives for Ae. aegypti control.
Ana Cristina Tissot
Full Text Available A Coleção de Entomologia do Departamento de Zoologia da Universidade Federal do Paraná (DZUP abriga cerca de 5.000.000 de exemplares de insetos. A coleção de Diptera está representada por aproximadamente 2.000.000 de exemplares, sendo Muscidae; Culicidae e Syrphidae as famílias mais representativas. A ordem Diptera possui cerca de 150.000 espécies descritas e a coleção conta com cerca de 103.000 exemplares representantes de 78 famílias. A lista das espécies pertencentes à família Culicidae conta com 9.579 exemplares, distribuídos em 2 subfamílias, 7 tribos, 17 gêneros, 26 subgêneros e 85 espécies. A maioria dos exemplares foi coletado em remanescentes de mata localizados em áreas urbanas e rurais, ambientes silvestres e urbanos de regiões litorâneas ou áreas urbanas pertencentes a diferentes cidades do Estado do Paraná, e algumas espécies incluídas foram capturadas nos Estados de São Paulo, Mato Grosso, Santa Catarina e no Distrito Federal. As informações específicas de cada exemplar, como local de coleta, latitude, longitude, coletor, data de coleta, método de coleta e nome do pesquisador que identificou, e também informações taxonômicas como ordem, tribo, gênero, subgênero e espécie, foram informatizados em um banco de dados.The Entomological Collection of Departamento de Zoologia of Universidade Federal do Paraná (DZUP accommodates about 5,000,000 insect specimens. The collection of Diptera is represented by approximately 2,000,000 specimens, being Muscidae, Culicidae and Syrphidae the most representative families. The Diptera order consists of approximately 150,000 described species and in the Collection about 103,000 specimens within 78 families are registered. The list of species of the family Culicidae presents 9,579 specimens within 2 subfamilies, 7 tribes, 17 genera, 26 subgenera and 85 species. Most specimens were captured in forest remnants in urban and rural areas, wild and urban environments in
Mint Lekweiry, Khadijetou; Ould Ahmedou Salem, Mohamed Salem; Ould Brahim, Khyarhoum; Ould Lemrabott, Mohamed Aly; Brengues, Cécile; Faye, Ousmane; Simard, Frédéric; Ould Mohamed Salem Boukhary, Ali
Aedes aegypti L. (Diptera: Culicidae) is a major vector of yellow fever, dengue, and chikungunya viruses throughout tropical and subtropical areas of the world. Although the southernmost part of Mauritania along the Senegal river has long been recognized at risk of yellow fever transmission, Aedes spp. mosquitoes had never been reported northwards in Mauritania. Here, we report the first observation of Aedes aegypti aegypti (L.) and Aedes (Ochlerotatus) caspius (Pallas, 1771) in the capital city, Nouakchott. We describe the development sites in which larvae of the two species were found, drawing attention to the risk for emergence of arbovirus transmission in the city. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Asma Mahmoud Hamza
Full Text Available Anopheles arabiensis Patton (Diptera: Culicidae is considered the most efficient malaria vector in eastern Sudan. This study aims to characterize the breeding sites of An. arabiensis throughout the year in and around Kassala town, eastern Sudan. Diverse larval habitat types were visited and characterized based on the habitat type and chemical composition. Mosquito larvae were found in many diverse habitats. During the rainy season, rain pools and water bodies created by the seasonal Gash River serve as the main breeding sites. In the dry season, irrigation canals, seepage from water pipes, neglected wells, artificial containers, and man-made ditches serve as the main breeding sites. Breeding water showed a pH of 7.9 and a low concentration of the total dissolved salts. The results of this study may be considered in planning and implementing larval control programs in the area.
Johnson, Tammi L; Haque, Ubydul; Monaghan, Andrew J; Eisen, Lars; Hahn, Micah B; Hayden, Mary H; Savage, Harry M; McAllister, Janet; Mutebi, John-Paul; Eisen, Rebecca J
The mosquitoes Aedes (Stegomyia) aegypti (L.)(Diptera:Culicidae) and Ae. (Stegomyia) albopictus (Skuse) (Diptera:Culicidae) transmit dengue, chikungunya, and Zika viruses and represent a growing public health threat in parts of the United States where they are established. To complement existing mosquito presence records based on discontinuous, non-systematic surveillance efforts, we developed county-scale environmental suitability maps for both species using maximum entropy modeling to fit climatic variables to county presence records from 1960-2016 in the contiguous United States. The predictive models for Ae. aegypti and Ae. albopictus had an overall accuracy of 0.84 and 0.85, respectively. Cumulative growing degree days (GDDs) during the winter months, an indicator of overall warmth, was the most important predictive variable for both species and was positively associated with environmental suitability. The number (percentage) of counties classified as environmentally suitable, based on models with 90 or 99% sensitivity, ranged from 1,443 (46%) to 2,209 (71%) for Ae. aegypti and from 1,726 (55%) to 2,329 (75%) for Ae. albopictus. Increasing model sensitivity results in more counties classified as suitable, at least for summer survival, from which there are no mosquito records. We anticipate that Ae. aegypti and Ae. albopictus will be found more commonly in counties classified as suitable based on the lower 90% sensitivity threshold compared with the higher 99% threshold. Counties predicted suitable with 90% sensitivity should therefore be a top priority for expanded mosquito surveillance efforts while still keeping in mind that Ae. aegypti and Ae. albopictus may be introduced, via accidental transport of eggs or immatures, and potentially proliferate during the warmest part of the year anywhere within the geographic areas delineated by the 99% sensitivity model. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work
Full Text Available Spatial evaluation of Culicidae (Diptera larvae from different breeding sites: application of a geospatial method and implications for vector control. This study investigates the spatial distribution of urban Culicidae and informs entomological monitoring of species that use artificial containers as larval habitats. Collections of mosquito larvae were conducted in the São Paulo State municipality of Santa Bárbara d' Oeste between 2004 and 2006 during house-to-house visits. A total of 1,891 samples and nine different species were sampled. Species distribution was assessed using the kriging statistical method by extrapolating municipal administrative divisions. The sampling method followed the norms of the municipal health services of the Ministry of Health and can thus be adopted by public health authorities in disease control and delimitation of risk areas. Moreover, this type of survey and analysis can be employed for entomological surveillance of urban vectors that use artificial containers as larval habitat.
Cleandson Ferreira SANTOS
Full Text Available In Brazil, most studies of the Culicidae family are concentrated in rainforest regions. As such, there is a lack of knowledge regarding the diversity of Culicidae in regions with different climatic and vegetational characteristics. The aim of this study was to compile an inventory of Culicidae in protected areas of the semi-arid region of the state of Minas Gerais, Brazil, in order to better understand the diversity of the family within this region. The study was conducted across four protected areas in the northern region of the state, in tropical dry forest (TDF fragments. Sampling methods included Shannon trap and CDC light trap, as well as active collection. A total of 11,219 mosquito specimens were collected between August 2008 and July 2012, belonging to 11 genera and 45 species; 15 new records for the state of Minas Gerais were registered, as well as 26 new records for semi-arid regions within the state. The high number of new Culicidae records in this region demonstrates the importance of inventory studies for increasing the knowledge of culicid biodiversity in Minas Gerais, and in particular within semi-arid regions of the state.
Santos, Cleandson Ferreira; Silva, Alex Chavier; Rodrigues, Raquel Andrade; de Jesus, Jamilli Sanndy Ramos; Borges, Magno Augusto Zazá
In Brazil, most studies of the Culicidae family are concentrated in rainforest regions. As such, there is a lack of knowledge regarding the diversity of Culicidae in regions with different climatic and vegetational characteristics. The aim of this study was to compile an inventory of Culicidae in protected areas of the semi-arid region of the state of Minas Gerais, Brazil, in order to better understand the diversity of the family within this region. The study was conducted across four protected areas in the northern region of the state, in tropical dry forest (TDF) fragments. Sampling methods included Shannon trap and CDC light trap, as well as active collection. A total of 11,219 mosquito specimens were collected between August 2008 and July 2012, belonging to 11 genera and 45 species; 15 new records for the state of Minas Gerais were registered, as well as 26 new records for semi-arid regions within the state. The high number of new Culicidae records in this region demonstrates the importance of inventory studies for increasing the knowledge of culicid biodiversity in Minas Gerais, and in particular within semi-arid regions of the state.
Cook, Shelley; Diallo, Mawlouth; Sall, Amadou A; Cooper, Alan; Holmes, Edward C
Correct classification of the insect vector is central to the study of arboviral disease. A simple molecular method for identification of the main vectors of the mosquito-borne viruses, dengue, yellow fever, and Rift Valley fever in Senegal, West Africa, was developed. We present a system in which the five mosquito species (Diptera: Culicidae) responsible for the majority of flaviviral disease transmission in Senegal can be reliably identified using small amounts of DNA coextracted during flaviviral screening procedures, via an easy amplification of the mitochondrial gene cytochrome oxidase c subunit I or II (COI or COII, respectively). We observed that despite very similar morphology, the two cryptic disease vector species Aedes furcifer Edwards and Aedes taylori Edwards are highly divergent at the molecular level. This sequence variation was used as a basis for the development of a polymerase chain reaction-restriction fragment-length polymorphism system for the differentiation of the two species. We also present the first investigation of the phylogeny of the culicine mosquitoes based on all COI and COII sequences currently available. There seems to be very low intraspecific variation in both genes, whereas interspecific variation is high. As a consequence, COI and COII are ideal candidates for the molecular identification of disease vectors to species level, whereas deeper divergences remain equivocal by using these genes. This system provides a new technique for the accurate identification of culicine disease vectors in West Africa and provides a basis for the expansion of such methods into the study of a range of diseases.
Demirci, Berna; Durmaz, Esra; Alten, Bulent
Culex theileri Theobald (Diptera: Culicidae) has a wide Afrotropical, southern Palaearctic, northern Oriental, and European distribution. It is mainly considered as a mammophilic mosquito and also feeds on birds and serves as a vector for various zoonotic diseases including West Nile virus. Despite its broad distribution and evidence indicating that Cx. theileri is a competent vector of human and domestic animal pathogens, basic biological and ecological features of this species have not been well investigated. We evaluated the impact of bloodmeal source (human, chicken, cow, and a double bloodmeal such as human and cow or chicken and cow and mixed bloodmeals [cow, chicken, and human] via artificial feeding) on fecundity, hatching rates, developmental times, and viability from egg to adult for laboratory colonized Cx. theileri. Fecundity in mosquitoes that took a chicken bloodmeal, a double bloodmeal and mixed bloodmeals was significantly higher than in females fed on a single cow or single human blood. This is the first study about the bloodmeal sources effect on laboratory-reared Cx. theileri populations and these findings contribute to our understanding of the impact of bloodmeal source on reproduction in Cx. theileri. As it is known that Cx. theileri is a vector for West Nile virus, the potential impacts of bloodmeal source on virus transmission are discussed. © 2014 Entomological Society of America.
Garelli, F M; Espinosa, M O; Weinberg, D; Coto, H D; Gaspe, M S; Gürtler, R E
A citywide control program of Aedes aegypti (L.) (Diptera: Culicidae) mainly based on the use of larvicides reduced infestations but failed to achieve the desired target levels in Clorinda, northeastern Argentina, over 5 yr of interventions. To understand the underlying causes of persistent infestations and to develop new control tactics adapted to the local context, we conducted two pupal surveys in a large neighborhood with approximately 2,500 houses and recorded several variables for every container inspected in fall and spring 2007. In total, 4,076 lots and 4,267 containers were inspected over both surveys, and 8,391 Ae. aegypti pupae were collected. Large tanks used for potable water storage were the most abundant and the most productive type of container, accounting for 65-84% of all the pupae collected. Therefore, large tanks were key containers and candidates for improved targeted interventions. Multivariate analysis showed that containers located in the yard, at low sun exposure, unlidded, filled with rain water, and holding polluted water were all more likely to be infested by larvae or pupae. When only infested containers were considered, productivity of pupae was most closely associated with large tanks and rain water. A stochastic simulation model was developed to calculate the expected correlations between pupal and Stegomyia indices according to the characteristics of the distribution of larvae and pupae per container and the spatial scale at which the indices were computed. The correlation between pupal and Stegomyia indices is expected to increase as infestation levels decline.
Full Text Available Background: Dengue is amongst the most serious mosquito-borne infectious disease with hot spots in tropical and subtropical parts of the world. Unfortunately, no licensed vaccine for the disease is currently available in medicine markets. The only option available is the management of dengue vector mosquito, Aedes aegypti (Diptera: Culicidae.Method: Predatory potential of five odonate nymphs namely Anax parthenope, Bradinopyga geminate, Ischnura forcipata, Rhinocypha quadrimaculata, and Orthetrum sabina were evaluated against the 4th instar larvae of the dengue vector mosquito, Aedes aegypti, under laboratory conditions. The consumption of the mosquito larvae was evaluated at three water volume levels viz., 1 liter, 2 liter and 3 liter.Results: The number of Ae. aegypti larvae consumed varied significantly among the five species, and at different levels of water volume (P< 0.01. However, the interaction between odonate nymphs and the water volumes was statistically non-significant (P> 0.05. Ischnura forcipata consumed the highest number of Ae. aegypti larvae (n=56 followed by A. parthenope (n=47 and B. geminate (n=46. The number of larvae consumed was decreased with increasing search area or water volume, and the highest predation was observed at 1-liter water volume.Conclusion: The odonate nymphs could be a good source of biological agents for the management of the mosquitoes at larval stages.
Songsawatkiat, Siripan; Baimai, Visut; Thongsahuan, Sorawat; Otsuka, Yasushi; Taai, Kritsana; Hempolchom, Chayanit; Srisuka, Wichai; Poolphol, Petchaboon; Choochote, Wej; Saeung, Atiporn
Metaphase karyotype investigation on two allopatric strains of Anopheles nitidus Harrison, Scanlon, and Reid (Diptera: Culicidae) was conducted in Thailand during 2011-2012. Five karyotypic forms, i.e., Form A (X1, Y1), Form B (X1, Y2), Form C (X2, Y3), Form D (X1, X3, Y4), and Form E (X1, X2, X3, Y5) were obtained from a total of 21 isofemale lines. Forms A, B, and C were confined to Phang Nga Province, southern Thailand, whereas Forms D and E were restricted to Ubon Ratchathani Province, northeastern Thailand. Cross-mating experiments among the five isofemale lines, which were representative of five karyotypic forms of An. nitidus, revealed genetic compatibility by providing viable progenies and synaptic salivary gland polytene chromosomes through F2 generations. The results suggest that the forms are conspecific, and An. nitidus comprises five cytological races. The very low intraspecific sequence variations (average genetic distances = 0.002-0.008) of the nucleotide sequences in ribosomal DNA (internal transcribed spacer 2) and mitochondrial DNA (cytochrome c oxidase subunits I and II) among the five karyotypic forms were very good supportive evidence. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.
Bartlett-Healy, Kristen; Crans, Wayne; Gaugler, Randy
The blood meals of field-collected female Culex territans (Diptera: Culicidae) were concurrently assayed for the presence of trypanosomes and for vertebrate host identification. We amplified vertebrate DNA in 42 of 119 females and made positive identification to the host species level in 29 of those samples. Of the 119 field-collected Cx. territans females, 24 were infected with trypanosomes. Phylogenetic analysis placed the trypanosomes in the amphibian portion of the aquatic clade of the Trypanosomatidae. These trypanosomes were isolated from Cx. territans females that had fed on the frog species Rana clamitans, R. catesbeiana, R. virgatipes, and Rana spp. Results support a potential new lineage of dipteran-transmitted amphibian trypanosomes may occur within the aquatic clade. The frequency in which female Cx. territans acquire trypanosomes, through diverse feeding habits, indicates a new relationship between amphibian trypanosomes and mosquitoes that has not been examined previously. Combining Trypanosoma species, invertebrate, and vertebrate hosts to existing phylogenies can elucidate trypanosome and host relationships.
María L. PESCHIUTTA
Full Text Available Aedes aegypti (Linnaeus (Diptera: Culicidae es vector de los agentes etiológicos de la fiebre amarilla y del dengue. Una alternativa al control químico de este vector es el uso de agentes biológicos. Los nematodos entomopatógenos son efectivos en el control de plagas. La infectividad y el ciclo de vida de un aislado argentino de Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae en larvas de A. aegypti se registró por primera vez bajo condiciones de laborato - rio. Para cada unidad experimental, 30 larvas de mosquito de segundo estadio fueron expuestas a 8 dosis del nematodo (0:1, 1:1, 5:1, 15:1, 100:1, 500:1, 750:1, 1500:1. Los juveniles infectivos (JIs utilizados fueron multiplicados sobre Galleria mellonella (Lepidoptera: Pyralidae. La continuidad infectiva de los JIs obtenidos de A. aegypti fue probada aplicándolos en una dosis de 100:1 sobre larvas del mosquito . Las tasas de mortalidad fueron de 0% a 84%. El número de nematodos desarrollados dentro de la larva de mosquito, la mortalidad larval y los nuevos JIs se incrementaron con el aumento de la dosis de nematodos. Los resultados indican que H. bacteriophora es capaz de infectar larvas de A. aegypti , se desarrolla y produce nuevos JIs, permitiendo la continuidad de su ciclo de vida.
Clarice Noleto Dias
Full Text Available The mosquito Aedes aegypti L. (Diptera: Culicidae is the major vector of dengue and chikungunya fever. The lack of effective therapies and vaccines for these diseases highlights the need for alternative strategies to control the spread of virus. Therefore, this study investigated the larvicidal potential of essential oils from common plant species obtained from the Chapada das Mesas National Park, Brazil, against third instar A. aegypti larvae. The chemical composition of these oils was determined by gas chromatography coupled to mass spectrometry. The essential oils of Eugenia piauhiensis Vellaff., Myrcia erythroxylon O. Berg, Psidium myrsinites DC., and Siparuna camporum (Tul. A. DC. were observed to be mainly composed of sesquiterpene hydrocarbons. The essential oil of Lippia gracilis Schauer was composed of oxygenated monoterpenes. Four of the five tested oils were effective against the A. aegypti larvae, with the lethal concentration (LC50 ranging from 230 to 292 mg/L after 24 h of exposure. Overall, this work demonstrated the possibility of developing larvicidal products against A. aegypti by using essential oils from the flora of the Brazilian Legal Amazon. This in turn demonstrates the potential of using natural resources for the control of disease vectors.
Lang, Bethan J; Idugboe, Stefano; McManus, Kirelle; Drury, Florence; Qureshi, Alima; Cator, Lauren J
Control of Aedes aegypti (L.) (Diptera: Culicidae) populations is vital for reducing the transmission of several pervasive human diseases. The success of new vector control technologies will be influenced by the fitness of laboratory-reared transgenic males. However, there has been relatively little published data on how rearing practices influence male fitness in Aedes mosquitoes. In the laboratory, the effect of larval food availability on adult male fitness was tested, using a range of different fitness measures. Larval food availability was demonstrated to be positively correlated with adult body size. Larger males survived longer and exhibited greater swarming activity. As a consequence, larger males may have more mating opportunities in the wild. However, we also found that within a swarm larger males did not have an increased likelihood of copulating with a female. The outcome of the mating competition experiments depended on the methodology used to mark the males. These results show that fitness assessment can vary depending on the measure analyzed, and the methodology used to determine it. Continued investigation into these fitness measures and methodologies, and critically, their utility for predicting male performance in the field, will increase the efficiency of vector control programs. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America.
Sarkar, Manas; Akulwad, Ambadas; Kshirsagar, Rajendra; Muthukrishnan, Siva
Intensive exposure to insecticides has resulted in the evolution of insecticide resistance in the mosquitoes. We tested the bio-efficacy of two Culex quinquefasciatus Say (Diptera: Culicidae) laboratory strains differentially bio-responsive to pyrethroids to understand the comparative efficacy of different polyfluorobenzyle and conventional pyrethroid molecules and the role of piperonyl butoxide (PBO) in synergizing these molecules in increased tolerance of mosquitoes to these molecules. We have taken deltamethrin (α-cyano pyrethroid with phenoxybenzyl moiety); permethrin (phenoxybenzyl pyrethroid without an α-cyano group); transfluthrin, dimefluthrin, metofluthrin, and meperfluthrin (polyfluorinated benzyl compounds); and prallethrin (modified cyclopentadienone compound) for this study. We found higher bio-efficacy in dimefluthrin, metofluthrin, and meperfluthrin compared with transfluthrin against tested mosquito strains. We found that transfluthrin exhibited synergism with PBO, which supports the hypothesis that P450 enzymes could play a role in the detoxification process of transfluthrin, which was earlier not believed. However, other polyfluorobenzyl pyrethroids with a 4-(methoxymethyl) phenyl capping in the tetrafluorobenzyl ring (dimefluthrin, metofluthrin, and meperfluthrin) exhibit greater synergism with PBO compared with transfluthrin. Further study is required to understand the mechanism for higher synergistic ratios in polyfluorobenzyl pyrethroids with 4-(methoxymethyl) phenyl moiety and ascertain the possible involvement of novel mechanisms that may involve in developing resistance. This is the first report of comparative bio-efficacy of multiple polyfluorobenzyl pyrethroids and PBO synergism against mosquitoes.
Hernández-Triana, Luis Miguel; Brugman, Victor Albert; Prosser, Sean Williams John; Weland, Chris; Nikolova, Nadya; Thorne, Leigh; Marco, Mar Fernández DE; Fooks, Anthony Richard; Johnson, Nicholas
Thirty-four species of Culicidae are present in the UK, of which 15 have been implicated as potential vectors of arthropod-borne viruses such as West Nile virus. Identification of mosquito feeding preferences is paramount to the understanding of vector-host-pathogen interactions which, in turn, would assist in the control of disease outbreaks. Results are presented on the application of DNA barcoding for vertebrate species identification in blood-fed female mosquitoes in rural locations. Blood-fed females (n = 134) were collected in southern England from rural sites and identified based on morphological criteria. Blood meals from 59 specimens (44%) were identified as feeding on eight hosts: European rabbit, cow, human, barn swallow, dog, great tit, magpie and blackbird. Analysis of the cytochrome c oxidase subunit I mtDNA barcoding region and the internal transcribed spacer 2 rDNA region of the specimens morphologically identified as Anopheles maculipennis s.l. revealed the presence of An. atroparvus and An. messeae. A similar analysis of specimens morphologically identified as Culex pipiens/Cx. torrentium showed all specimens to be Cx. pipiens (typical form). This study demonstrates the importance of using molecular techniques to support species-level identification in blood-fed mosquitoes to maximize the information obtained in studies investigating host feeding patterns.
geografica actualizada. Rev. Inv. Salud Publica (Mexico) 33: 11 I - 125. Heinemann, S.J. and J.N. Belkin. 1977. Collection records of the project...Mosquitoes of Middle America” 8. Central America: Belize (BH), Guatemala (GUA), El Salvador ( SAL ), Honduras (HON), Nicaragua (NI, NIC). Mosq. Syst...Culicidae). Ill. Nat. Hist. Surv. Biol. Notes 52, 50 pp. Vargas, L. 1956. Especies y distribucidn de mosquitos mexicanos no anofelinos. Rev. Instit. de
Zittra, Carina; Obwaller, Adelheid G; Wimmer, Victoria; Berer, Dominik; Eigner, Barbara; Fuehrer, Hans-Peter
During a three-year mosquito monitoring from 2014 to 2016, the strictly ornithophilic, originally Mediterranean species Orthopodomyia pulcripalpis (Rondani, 1872) was collected as single specimen for the first time in Austria in the district of Penzing in Vienna. Morphological species determination was confirmed by analysis of the mitochondrial cytochrome c oxidase subunit I gene. We thus not only confirm the existence of another mosquito species in Austria, but also add a new genus to the Austrian Culicidae taxa list.
Full Text Available This study describes the aquatic habitats, species composition, and the insecticide resistance level of the mosquito Culex pipiens pallens in Shandong Province, China. A cross-sectional survey of mosquito larval habitats was conducted from May to November 2014 to determine the species composition and larval abundance. Larvae were collected using the standard dipping technique, and a total of four habitat types were sampled. The fourth instar larvae of Cx. pipiens pallens collected in each habitat type were tested for resistance to five insecticides according to a WHO bioassay. A total of 7,281 mosquito larvae were collected, of which 399 (5.48% were categorized as Anopheles mosquito larvae ( An. sinensis , 6636 (91.14% as culicine larvae ( Cx. pipiens pallens, Cx. tritaeniorhynchus, Cx. halifaxii, and Cx. bitaeniorhynchus , 213 (2.93% as Armigeres larvae, and 33 (0.45% as Aedes larvae ( Aedes albopictus . In addition, a total of 1,149 mosquito pupae were collected. Culex larvae were distributed in all habitats investigated. Tukeys HSD analysis showed that roadside drainages were the most productive habitat type for Culex larvae. Armigeres species were found only in drains, Aedes only in water tanks, and Anopheles in water that was comparatively clear and rich in emergent plants. Bioassay showed that the maximum resistance level of Cx. pipiens pallens was to deltamethrin, while it was lowest to plifenate. The productivity of various mosquitoes in different habitat types is very heterogeneous. It is particularly important to modify human activity and the environment to achieve effective mosquito vector control. For effective larval control, the type of habitat should be considered, and the most productive habitat type should be given priority in mosquito abatement programs.
Full Text Available Objective: To get new data about the ecology of mosquitoes, which would be valuable to develop programs for future provision of mosquito controls in the study area. Methods: During April to September 2012, larvae of mosquitoes were collected from six counties in south of Fars Province using dipping method. Characteristics of larval breeding places were considered based on water conditions. Species diversity was examined in terms of alpha and beta measures, with the intent of comparing mosquito diversity according to the typology of regions. Results: During this investigation, totally, 5 057 larvae of mosquitoes belonging to 5 genera and 17 different mosquito species were recognized, namely, Anopheles dthali, Anopheles fluviatilis, Anopheles stephensi, Anopheles superpictus, Culex quinquefasciatus (Cx. quinquefasciatus, Culex mimeticus, Culex perexiguus, Culex pipiens (Cx. pipiens, Culex tritaeniorhynchus, Culex theileri (Cx. theileri, Culex tritaeniorhynchus, Culex sinaiticus, Culex torrentium, Culex modestus, Ochlerotatus caspius, Culiseta longiareolata and Aedes vexans (Ae. vexans. This is the first record of Ae. vexans, Culex perexiguus and Culex modestus in the Province. Cx. pipiens (27.3%, Cx. theileri (15.9% and Cx. quinquefasciatus (9.4% were the most abundant species found respectively. Cx. pipiens reached the highest density in August and July, while Cx. theileri, Cx. quinquefasciatus and Ae. vexans were found in high numbers in June. Diversity analysis indicated the highest species diversity in the Mohr County (Margalef index of 1.41 and Shannon index of 1.7 and the lowest species diversity in the Lamerd County (Margalef index of 0.33 and Shannon index of 0.38. Conclusions: Regarding to this research, there are some potential vectors of medical and veterinary importance in Fars Province. Results of the present study may serve as a basis for risk assessment of emerging mosquito-borne diseases.
Transcriptional Analysis of Four Family 4 P450s in a Puerto Rico Strain of Aedes aegypti (Diptera: Culicidae) Compared With an Orlando Strain and Their Possible Functional Roles in Permethrin Resistance
MOLECULAR BIOLOGY/GENOMICS Transcriptional Analysis of Four Family 4 P450s in a Puerto Rico Strain of Aedes aegypti (Diptera: Culicidae) Compared...10.1603/ME13228 ABSTRACT A Þeld strain of Aedes aegypti (L.) was collected from Puerto Rico in October 2008. Based onLD50 values by topical application...important role in cytochrome P450-mediated resistance to permethrin. KEY WORDS Aedes aegytpi, permethrin, resistance, cytochrome P450, detoxiÞcation The
QIU, YU TONG; SMALLEGANGE, RENATE C.; TER BRAAK, CAJO J. F.; SPITZEN, JEROEN; VAN LOON, JOOP J. A.; JAWARA, MUSA; MILLIGAN, PAUL; GALIMARD, AGNES M.; VAN BEEK, TERIS A.; KNOLS, BART G. J.; TAKKEN, WILLEM
Chemical cues play an important role in the host-seeking behavior of blood-feeding mosquitoes (Diptera: Culicidae). A field study was carried out in The Gambia to investigate the effects of human odor or synthetic odor blends on the attraction of mosquitoes. MM-X traps baited with 16 odor blends to which carbon dioxide (CO2) was added were tested in four sets of experiments. In a second series of experiments, MM-X traps with 14 odor blends without CO2 were tested. A blend of ammonia and l-lactic acid with or without CO2 was used as control odor in series 1 and 2, respectively. Centers for Disease Control and Prevention (CDC) traps were placed in a traditional house and an experimental house to monitor mosquito densities during the experiments. The MM-X traps caught a total number of 196,756 mosquitoes, with the most abundant species belonging to the genera Mansonia (70.6%), Anopheles (17.5%), and Culex (11.5%). The most abundant mosquito species caught by the CDC traps (56,290 in total) belonged to the genera Mansonia (59.4%), Anopheles (16.0% An. gambiae s.l. Giles, and 11.3% An. ziemanni Grünberg), and Culex (11.6%). MM-X traps baited with synthetic blends were in many cases more attractive than MM-X traps baited with human odors. Addition of CO2 to synthetic odors substantially increased the catch of all mosquito species in the MM-X traps. A blend of ammonia + L-lactic acid + CO2 + 3-methylbutanoic acid was the most attractive odor for most mosquito species. The candidate odor blend shows the potential to enhance trap collections so that traps will provide better surveillance and possible control. PMID:18047195
Full Text Available Background & objectives: In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticide, this study was undertaken to assess the larvicidal and ovicidal potential of the crude hexane, benzene, chloroform, ethyl acetate and methanol solvent extracts from the medicinal plant Pithecellobium dulce against the mosquito vectors, Anopheles stephensi and Aedes aegypti (Diptera: Culicidae. Methods: Larvicidal activity of P. dulce plant extracts was studied in the range of 60 to 450 mg/l against early third instar larvae of An. stephensi and Ae. aegypti in the laboratory. The larval mortality was observed after 24 h of exposure. The ovicidal activity was determined against An. stephensi and Ae. aegypti to various concentrations ranging from 100 to 750 mg/l under the laboratory conditions. Mean per cent hatchability of the eggs were observed after 48 h post treatment. Results: All leaf and seed extracts showed moderate larvicidal and ovicidal effects; however, the highest larval mortality was found in methanol extract of leaf of P. dulce against the larvae of An. stephensi and Ae. aegypti with the LC 50 and LC 90 values 145.43, 155.78 mg/l and 251.23, 279.73 mg/l, respectively. The per cent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. Zero hatchability was observed at 400 mg/l for leaf methanol extract and 625 mg/l for seed methanol extract of P. dulce against An. stephensi and Ae. aegypti, respectively. Compared to leaf extracts, seed extracts have low potency against the two mosquitoes. Interpretation & conclusions: The present results suggest that the leaf and seed extracts of P. dulce have the potential to be used as an ideal eco-friendly approach for the control of mosquitoes.
Govindarajan, M; Rajeswary, M; Sivakumar, R
In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticide, this study was undertaken to assess the larvicidal and ovicidal potential of the crude hexane, benzene, chloroform, ethyl acetate and methanol solvent extracts from the medicinal plant Pithecellobium dulce against the mosquito vectors, Anopheles stephensi and Aedes aegypti (Diptera: Culicidae). Larvicidal activity of P. dulce plant extracts was studied in the range of 60 to 450 mg/l against early third instar larvae of An. stephensi and Ae. aegypti in the laboratory. The larval mortality was observed after 24 h of exposure. The ovicidal activity was determined against An. stephensi and Ae. aegypti to various concentrations ranging from 100 to 750 mg/l under the laboratory conditions. Mean per cent hatchability of the eggs were observed after 48 h post treatment. All leaf and seed extracts showed moderate larvicidal and ovicidal effects; however, the highest larval mortality was found in methanol extract of leaf of P. dulce against the larvae of An. stephensi and Ae. aegypti with the LC₅₀ and LC₉₀ values 145.43, 155.78 mg/l and 251.23, 279.73 mg/l, respectively. The per cent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. Zero hatchability was observed at 400 mg/l for leaf methanol extract and 625 mg/l for seed methanol extract of P. dulce against An. stephensi and Ae. aegypti, respectively. Compared to leaf extracts, seed extracts have low potency against the two mosquitoes. The present results suggest that the leaf and seed extracts of P. dulce have the potential to be used as an ideal eco-friendly approach for the control of mosquitoes.
Bernués Bañeres, Alberto
La familia Culicidae incluye algunas de las especies de dípteros más relevantes en el ámbito de la Salud Pública, no solo por las molestias que son capaces de causar debido a su tipo de alimentación hematófaga, sino por su capacidad para actuar como vectores de enfermedades de afección humana. Por este motivo, los mosquitos han sido, desde siempre, una de las dianas predilectas en los programas de control establecidos para la regulación de sus poblaciones y, por tanto, como medida profiláctic...
Almério de Castro Gomes
Full Text Available A Adultrap é uma nova armadilha feita para capturar fêmeas de Aedes aegypti. Foram realizados testes para avaliar sua especificidade tendo como referência a técnica da aspiração da espécie em abrigos artificiais. A Adultrap ficou exposta por 24 horas no intradomicílio e peridomicílio de 120 casas sorteadas em dois bairros da Cidade de Foz do Iguaçu, Estado do Paraná. O teste estatístico foi o modelo log-linear de Poisson. O resultado foi a captura de 726 mosquitos Culicidae, dos quais 80 eram Aedes aegypti. A Adultrap capturou apenas fêmeas desta espécie, enquanto o aspirador os dois sexos de Aedes aegypti e mais cinco outras espécies. A Adultrap capturou Aedes aegypti dentro e fora das casas, mas a análise indicou que no peridomicílio a armadilha capturou significantemente mais fêmeas do que a aspiração. Também, ficou evidenciada a sensibilidade da Adultrap para detectar Aedes aegypti em situação de baixa freqüência.The Adultrap is a new trap built for capturing females of Aedes aegypti. Tests were carried out to evaluate the specificity of this trap in comparison with the technique of aspiration of specimens in artificial shelters. Adultraps were kept for 24 hours inside and outside 120 randomly selected homes in two districts of the city of Foz do Iguaçú, State of Paraná. The statistical test was Poisson’s log-linear model. The result was 726 mosquitoes captured, of which 80 were Aedes aegypti. The Adultrap captured only females of this species, while the aspiration method captured both sexes of Aedes aegypti and another five species. The Adultrap captured Aedes aegypti inside and outside the homes, but the analysis indicated that, outside the homes, this trap captured significantly more females than aspiration did. The sensitivity of the Adultrap for detecting females of Aedes aegypti in low-frequency situations was also demonstrated.
Turell, Michael J; Wilson, William C; Bennett, Kristine E
To determine which arthropods should be targeted for control should Rift Valley fever virus (RVFV) be detected in North America, we evaluated Culex erraticus (Dyar and Knab), Culex erythrothorax Dyar, Culex nigripalpus Theobald, Culex pipiens L., Culex quinquefasciatus Say, Culex tarsalis Coquillett, Aedes dorsalis (Wiedemann), Aedes vexans (Meigen), Anopheles quadrimaculatus Say, and Culicoides sonorensis Wirth and Jones from the western, midwestern, and southern United States for their ability to transmit RVFV. Female mosquitoes were allowed to feed on adult hamsters inoculated with RVFV, after which engorged mosquitoes were incubated for 7-21 d at 260C, then allowed to refeed on susceptible hamsters, and tested to determine infection, dissemination, and transmission rates. Other specimens were inoculated intrathoracically, held for 7 d, and then allowed to feed on a susceptible hamster to check for a salivary gland barrier. When exposed to hamsters with viremias > or =10(8.8) plaque-forming units/ml blood, Cx. tarsalis transmitted RVFV efficiently (infection rate = 93%, dissemination rate = 56%, and estimated transmission rate = 52%). In contrast, when exposed to the same virus dose, none of the other species tested transmitted RVFV efficiently. Estimated transmission rates for Cx. erythrothorax, Cx. pipiens, Cx. erraticus, and Ae. dorsalis were 10, 8, 4, and 2%, respectively, and for the remaining species were feeding preference, longevity, and foraging behavior should be considered when determining the potential role that these species could play in RVFV transmission.
Anthony Érico Guimarães
Full Text Available The ecology of anopheline species (Diptera, Culicidae was studied in the vicinity of the Serra da Mesa Reservoir, State of Goiás, Brazil. Climatic factors and frequency of anopheline populations were analyzed. Bimonthly human-bait and Shannon trap captures were conducted for 36 consecutive months (January 1997 through December 1999. A total of 5,205 adult anophelines belonging to five species were collected. Anopheles darlingi was the most frequently collected anopheline (61.4%, followed by An. albitarsis s.l. (35.4%, An. triannulatus. (2.5%, An. oswaldoi (0.4%, and An. evansae (0.2%. The water level and vegetation along the banks of the reservoir were crucial to the frequency of the various anopheline species. Climatic factors had a secondary influence. The reservoir's water-level stability, increased frequency of An. darlingi, and the arrival of gold prospectors were responsible for the increase in malaria cases.
Saavedra, Laura M; Romanelli, Gustavo P; Rozo, Ciro E; Duchowicz, Pablo R
The insecticidal activity of a series of 62 plant derived molecules against the chikungunya, dengue and zika vector, the Aedes aegypti (Diptera:Culicidae) mosquito, is subjected to a Quantitative Structure-Activity Relationships (QSAR) analysis. The Replacement Method (RM) variable subset selection technique based on Multivariable Linear Regression (MLR) proves to be successful for exploring 4885 molecular descriptors calculated with Dragon 6. The predictive capability of the obtained models is confirmed through an external test set of compounds, Leave-One-Out (LOO) cross-validation and Y-Randomization. The present study constitutes a first necessary computational step for designing less toxic insecticides. Copyright © 2017 Elsevier B.V. All rights reserved.
Collao, Ximena; Prado, Lorena; González, Christian; Vásquez, Ana; Araki, Romina; Henríquez, Tuki; Peña, Cindy M
Flaviviruses are arthropod-borne viruses, mainly by mosquitoes of the genera Aedes and Culex (Culicidae) that are detected in tropical and subtropical areas. Main flaviviruses of public health importance are: dengue, West Nile virus, yellow fever, among others. In continental Chile, flaviviruses has not been detected. However, there are indigenous cases of dengue detected in Easter Island since 2002, as the presence of its vector Aedes aegypti. The aim of this study was: To determine diversity of flavivirus mosquitoes present in Easter Island. Thirty pools of mosquitoes collected in Hanga Roa were analyzed; a RT-PCR nested flavivirus was performed. Thirteen positive samples were detected and the amplification products were sequenced, identifying two specific flavivirus Insect, the Cell fusing agent virus and other related viruses Kamiti River. This is the first study in Chile showed the presence of flavivirus in vectors in Easter Island.
Santa-Ana, Marta; Khadem, Manhaz; Capela, Ruben
Field and laboratory studies were performed to verify whether Culex theileri Theobald functions as a natural vector of Dirofilaria immitis (Leidy) on Madeira Island, Portugal. CO2-baited light traps (EVS traps) were use to sample mosquitoes monthly basis between February 2002 and February 2003 in the area of Quebradas (Funchal). Three mosquito species were captured, including 58 Culex pipiens L., 790 Cx. theileri, and three Culiseta longiareolata (Macquart). Only C. theileri tested positive for D. immitis. The presence of this filarial worm was detected by direct observation, infectivity assay dissection technique, and polymerase chain reaction methods. Infected mosquitoes were recovered in October and December 2002 and January 2003. These data provide evidence that Cx. theileri could be the main vector of D. immitis in Funchal, Madeira.
Al Ashry, Hamdy A; Kenawy, Mohamed A; Shobrak, Mohammed
An entomological survey was undertaken for one year to update the mosquito fauna of Asir Region, Kingdom of Saudi Arabia. A total of 31 species of 8 genera were reported of which genus Culex (55%) was the most common. Most of collected larvae (59%) belonged to genus Culex (+ Lutzia) followed by Culiseta (26%), Anopheles (13%) and Aedine spp. (2%). Cx. pipiens (39%) and Cs. longiareolata (26.%) were generally the most abundant of all collected larvae. Of the Anopheles spp., An. dthali was common (40%), of Culex spp., Cx. pipiens was predominating (66%) and of Aedine spp., St. aegypti was predominating (71%). Four species: An. fluviatilis, Cx. mattinglyi, Cx. arbieeni and Cx. mimeticus were new reports in Asir Region and Cx. wigglesworthi recorded for the first time from the kingdom. Larvae were more common in low- and highlands than in the moderately altitude areas. In general all species prefer stagnant water but with the exception of Aedine larvae (altogether), the other species prefer presence of algae, vegetation and shade and absence of turbidity (except Culex spp.). A total of 98 different forms of association were reported of which 9 forms were common. All genera breed year round with peaks of abundance during spring for Anopheles spp. and Culex spp. and during winter for Aedine spp. and Cs. longiareolata. A complete list of mosquito fauna of Asir Region comprising 45 spp. was presented based on the present and previous surveys. The study concluded that the occurrence and prevalence of mosquito species mainly the disease vectors in Asir carry the thread of maintaining and transmission of several mosquito-borne diseases.
Myriam Janeth Salazar
Full Text Available El objetivo de este trabajo fue estudiar varios aspectos del crecimiento y el desarrollo de los estadios inmaduros de Culex quinquefasciatus Say, 1826 (Diptera: Culicidae, especie antropofílica frecuentemente encontrada en Bogotá. Con este fin, se realizaron dos experimentos en diferentes épocas del año 2001 (enero-febrero y septiembre-octubre, bajo condiciones no controladas (luz, temperatura y humedad relativa. Se colocaron recipientes plásticos transparentes con agua de charca a la que se le adicionó concentrado para perro; se tomaron cuatro balsas al azar para estudiar el ciclo de vida utilizando los parámetros de la tabla de vida: mortalidad y supervivencia. Las hembras ovipositaron entre cinco y ocho días después de la ingestión de sangre. El número de huevos por balsa varió entre 152 y 203. La eclosión de larvas L1 fue de 50% en el primer experimento y de 75% en el segundo. Se destacó la naturaleza no sincrónica de la eclosión de las L1, la menor duración proporcional del estadio de pupa (11% del tiempo del desarrollo total y la eficiencia del cambio pupa-adulto (98,61%. Se reporta una menor duración del ciclo de lo informado previamente. Además, los altos porcentajes de eclosión (83,58%, pupación (86,63% y emergencia (98,61% con las condiciones presentes para estos experimentos (temperatura media 14,8°C y 15,1°C y humedad relativa del 72,5% y 74,1%, respectivamente indican el alto grado de adaptación de C. quinquefasciatus al ambiente bogotano. Estas características, más la capacidad vectorial y la resistencia a los insecticidas, hacen de esta especie un problema de salud pública.
Spatial evaluation of larvae of Culicidae (Diptera from different breeding sites: application of a geospatial method and implications for vector control Avaliação espacial de formas larvais de Culicidae (Diptera em diferentes criadouros: aplicação de um método geoespacial e implicações para o controle de vetores
Full Text Available Spatial evaluation of Culicidae (Diptera larvae from different breeding sites: application of a geospatial method and implications for vector control. This study investigates the spatial distribution of urban Culicidae and informs entomological monitoring of species that use artificial containers as larval habitats. Collections of mosquito larvae were conducted in the São Paulo State municipality of Santa Bárbara d' Oeste between 2004 and 2006 during house-to-house visits. A total of 1,891 samples and nine different species were sampled. Species distribution was assessed using the kriging statistical method by extrapolating municipal administrative divisions. The sampling method followed the norms of the municipal health services of the Ministry of Health and can thus be adopted by public health authorities in disease control and delimitation of risk areas. Moreover, this type of survey and analysis can be employed for entomological surveillance of urban vectors that use artificial containers as larval habitat.Avaliação espacial de formas larvais de Culicidae (Diptera em diferentes criadouros: aplicação de um método geoespacial e implicações para o controle de vetores. Este estudo investiga a distribuição espacial da fauna urbana e de Culicidae e informa o monitoramento entomológico de espécies que usam recipientes artificiais como habitat larval. Coletas de larvas de mosquitos foram realizadas no município paulista de Santa Bárbara d' Oeste entre os anos de 2004 e 2006, durante visitas casa-a-casa. Um total de 1.891 amostras foi considerado, com nove espécies diferentes coletadas. A distribuição das espécies foi avaliada através do método de krigagem estatística extrapolando as divisões administrativas do município. O método de coleta adotado no presente estudo está de acordo com os métodos sugeridos aos serviços de saúde municipais pelo Ministério da Saúde e pode, portanto, ser adotado pelas autoridades p
Full Text Available Several important diseases are transmitted by mosquitoes. Despite of the potential of the occurrence of some mosquito-borne diseases such as West Nile, dirofilariasis and malaria in the region, there is no recent study of mosquitoes in West Azerbaijan Province. The aim of this investigation was to study the fauna, composition and distribution of mosquitoes and the characteristics of their larval habitats in this province.Larvae and adult collections were carried out from different habitats using the standard methods in twenty five localities of seven counties across West Azerbaijan Province.Overall, 1569 mosquitoes including 1336 larvae and 233 adults were collected from 25 localities. The details of geographical properties were recorded. Five genera along with 12 species were collected and identified including: Anopheles claviger, An. maculipennis s.l., An. superpictus, Culex pipiens, Cx. theileri, Cx. modestus, Cx. hortensis, Cx. mimeticus, Culiseta Longiareolata, Ochlerotatus caspius s.l., Oc. geniculatus and Uranotaenia unguiculata. This is the first record of Oc. geniculatus in the province.Due to the geographical location of the West Azerbaijan Province, it comprises different climatic condition which provides suitable environment for the establishment of various species of mosquitoes. The solidarity geographical, cultural and territorial exchanges complicate the situation of the province and its vectors as a threat for future and probable epidemics of mosquito-borne diseases.
Brustolin, M; Talavera, S; Santamaría, C; Rivas, R; Pujol, N; Aranda, C; Marquès, E; Valle, M; Verdún, M; Pagès, N; Busquets, N
The emerging disease West Nile fever is caused by West Nile virus (WNV), one of the most widespread arboviruses. This study represents the first test of the vectorial competence of European Culex pipiens Linnaeus 1758 and Stegomyia albopicta (= Aedes albopictus) (both: Diptera: Culicidae) populations for lineage 1 and 2 WNV isolated in Europe. Culex pipiens and S. albopicta populations were susceptible to WNV infection, had disseminated infection, and were capable of transmitting both WNV lineages. This is the first WNV competence assay to maintain mosquito specimens under environmental conditions mimicking the field (day/night) conditions associated with the period of maximum expected WNV activity. The importance of environmental conditions is discussed and the issue of how previous experiments conducted in fixed high temperatures may have overestimated WNV vector competence results with respect to natural environmental conditions is analysed. The information presented should be useful to policymakers and public health authorities for establishing effective WNV surveillance and vector control programmes. This would improve preparedness to prevent future outbreaks. © 2016 The Authors. Medical and Veterinary Entomology published by John Wiley & Sons Ltd on behalf of Royal Entomological Society.
Full Text Available Salivary gland proteins of the human malaria vector, Anopheles dirus B were determined and analyzed. The amount of salivary gland proteins in mosquitoes aged between 3 - 10 days was approximately 1.08 ± 0.04 µg/female and 0.1 ± 0.05 µg/male. The salivary glands of both sexes displayed the same morphological organization as that of other anopheline mosquitoes. In females, apyrase accumulated in the distal regions, whereas alpha-glucosidase was found in the proximal region of the lateral lobes. This differential distribution of the analyzed enzymes reflects specialization of different regions for sugar and blood feeding. SDS-PAGE analysis revealed that at least seven major proteins were found in the female salivary glands, of which each morphological region contained different major proteins. Similar electrophoretic protein profiles were detected comparing unfed and blood-fed mosquitoes, suggesting that there is no specific protein induced by blood. Two-dimensional polyacrylamide gel analysis showed the most abundant salivary gland protein, with a molecular mass of approximately 35 kilodaltons and an isoelectric point of approximately 4.0. These results provide basic information that would lead to further study on the role of salivary proteins of An. dirus B in disease transmission and hematophagy.Proteínas das glândulas salivares do Anopheles dirus B (Diptera: Culicidae, vetor da malária humana foram determinadas e analisadas. A quantidade de proteínas das glândulas salivares em mosquitos com três a 10 dias de idade foi de aproximadamente 1,08 ± 0,04 µg/ fêmea e de 0,1 ± 0,05 µg/macho. As glândulas salivares de ambos os sexos mostraram organização morfológica semelhante à de outros mosquitos anofelinos. Em fêmeas, apirase acumula-se nas regiões distais, enquanto alfa-glucosidase foi encontrada na região proximal dos lóbulos laterais. Esta distribuição diferencial das enzimas analisadas reflete a especialização de
Fábio Alexandre Leal-Santos
Full Text Available Abstract. This study describes ecological data obtained in a rural area in the State of Mato Grosso, including the insects belonging to the family Culicidae, especially those framed as potential vectors of tropical diseases. In 2015, we collected adult mosquitoes in fragments of forest in a rural area located in Mato Grosso Central West of Brazil. We captured 18,256 mosquitoes of the sub-families Culicinae and Anophelinae and have identified 34 species belonging to 12 genera: Aedes (1 species, Anopheles (8 species, Coquillettidia (1 species, Haemagogus (1 species, Culex (5 species, Psorophora (5 species, Ochlerotatus (4 species, Deinocerites (1 species, Mansonia (4 species, Sabethes (2 species, Limatus (1 species, Wyeomyia (1 species. The family Culicidae presented high richness and abundance, established by diversity indexes (Margalef α =3.26; Shannon H' = 2.09; Simpson D = 0.19 with dominance of the species Anopheles (Nyssorhyncus darlingi Root (89.8%. This species has considerable epidemiological value, considered the main vector of malaria in Mato Grosso. Many species of mosquitoes are vectors of pathogens that cause disease in humans and domestic animals, transmitting pathogens including viruses (arboviruses, filaria worms (helminths and protozoa. Composição de espécies e distribuição da fauna de mosquitos (Diptera: Culicidae e sua importância para doenças transmitidas por vetores em uma área rural do centro-ocidental - Mato Grosso, Brasil Resumo. Este estudo descreve dados ecológicos de uma área rural do Estado de Mato Grosso e dos insetos da família Culicidae especialmente aqueles enquadrados como vetores potenciais de doenças tropicais. Em 2015, coletamos mosquitos adultos em fragmentos de floresta em localidades de áreas rurais no Mato Grosso região Centro Oeste do Brasil. Foram capturados 18.256 exemplares alados de mosquitos das subfamílias Culicinae e Anophelinae e identificadas 34 espécies pertencentes a 12 g
Vezzani, D; Albicócco, A P
The aim of this study was to assess whether certain attributes of larval breeding sites are correlated with pupal productivity (i.e. numbers of pupae collected per sampling period), so that these could be used as the focus for control measures to enhance control efficiency. Therefore, the objectives were to identify the months of highest pupal productivity of Aedes aegypti (L.) and Culex pipiens L. (Diptera: Culicidae) in an urban temperate cemetery in Argentina where artificial containers of containers and to determine whether the composition of the containers affected pupal productivity. Over a period of 9 months, 200 randomly chosen water-filled containers (100 sunlit and 100 shaded), out of approximately 3738 containers present (approximately 54% in shade), were examined each month within a cemetery (5 ha) in Buenos Aires (October 2006 to June 2007). In total, 3440 immatures of Cx pipiens and 1974 of Ae. aegypti were collected. The larvae : pupae ratio was 10 times greater for the former, indicating that larval mortality was greater for Cx pipiens. Both mosquito species showed a higher container index (CI) in shaded than in sunlit containers (Ae. aegypti: 12.8% vs. 6.9% [chi(2) = 17.6, P container and the number of pupae per pupa-positive container did not differ significantly between sunlit and shaded containers for either species. Therefore, the overall relative productivity of pupae per ha of Ae. aegypti and Cx pipiens was 2.3 and 1.8 times greater, respectively, in shaded than in sunlit areas as a result of the greater CIs of containers in shaded areas. Neither the CI nor the number of immatures per infested container differed significantly among container types of different materials in either lighting condition. The maximum CI and total pupal counts occurred in March for Ae. aegypti and in January and February for Cx pipiens. The estimated peak abundance of pupae in the whole cemetery reached a total of approximately 4388 in the middle of March for Ae
Ruth LM Ferreira
Full Text Available The community structure of insects, especially mosquito larvae, in water held in the fungus Aquascypha hydrophora (Berk. Reid (Stereaceae is reported. The study was done in the Adolpho Ducke Forest Reserve, 26 km east of Manaus, AM, Brazil, from September 1998 through November 1999. The most abundant entomofauna were immature Culicidae (n = 121 91.7%, followed by adult Dytiscidae (n = 3 2.3%, immature Chironomidae (n = 5 3.8% and immature Tipulidae (n = 3 2.3%. Culicidae associated with A. hydrophora comprised species of the subfamilies Anophelinae and Culicinae.
Chemical Compositions of the Peel Essential Oil of Citrus aurantium and its Natural Larvicidal Activity against the Malaria Vector Anopheles stephensi (Diptera: Culicidae in Comparison with Citrus paradisi
Full Text Available Background: Recently, essential oils and extracts derived from plants have received much interest as potential bioactive agents against mosquito vectors.Methods: The essential oils extract from fresh peel of ripe fruit of Citrus aurantium and Citrus paradisi were tested against mosquito vector Anopheles stephensi (Diptera: Culicidae under laboratory condition. Then chemical composition of the essential oil of C. aurantium was analyzed using gas chromatography-mass spectrometry (GC–MS.Results: The essential oils obtained from C. aurantium, and C. paradisi showed good larviciding effect against An. stephensi with LC50 values 31.20 ppm and 35.71 ppm respectively. Clear dose response relationships were established with the highest dose of 80 ppm plant extract evoking almost 100% mortality. Twenty-one (98.62% constituents in the leaf oil were identified. The main constituent of the leaf oil was Dl-limonene (94.81.Conclusion: The results obtained from this study suggest that the limonene of peel essential oil of C. aurantium is promising as larvicide against An. stephensi larvae and could be useful in the search for new natural larvicidal compounds.
Reiter, M.E.; Lapointe, D.A.
Effective management of avian malaria (Plasmodium relictum) in Hawai'i's endemic honeycreepers (Drepanidinae) requires the identification and subsequent reduction or treatment of larval habitat for the mosquito vector, Culex quinquefasciatus (Diptera: Culicidae). We conducted ground surveys, treehole surveys, and helicopter aerial surveys from 20012003 to identify all potential larval mosquito habitat within two 100+ ha mesic-dry forest study sites in Hawai'i Volcanoes National Park, Hawai'i; 'Ainahou Ranch and Mauna Loa Strip Road. At 'Ainahou Ranch, anthropogenic sites (43%) were more likely to contain mosquitoes than naturally occurring (8%) sites. Larvae of Cx. quinquefasciatus were predominately found in anthropogenic sites while Aedes albopictus larvae occurred less frequently in both anthropogenic sites and naturally-occurring sites. Additionally, moderate-size (???20-22,000 liters) anthropogenic potential larval habitat had >50% probability of mosquito presence compared to larger- and smaller-volume habitat (malaria, may be controlled by larval habitat reduction in the mesic-dry landscapes of Hawai'i where anthropogenic sources predominate.
Anthony Érico Guimarães
Full Text Available The mosquito (Diptera: Culicidae ecology was studied in areas of Serra do Mar State Park, State of São Paulo, Brazil. Systematized biweekly human bait collections were made three times a day, for periods of 2 or 3 h each, in sylvatic and rural areas for 24 consecutive months (January 1991 to December 1992. A total of 24,943 adult mosquitoes belonging to 57 species were collected during 622 collective periods. Aedes scapularis, Coquillettidia chrysonotum, Cq. venezuelensis, Wyeomyia dyari, Wy. longirostris, Wy. theobaldi and Wy. palmata were more frequently collected at swampy and at flooded areas. Anopheles mediopunctatus, Culex nigripalpus, Ae. serratus, Ae. fulvus, Psorophora ferox, Ps. albipes and the Sabethini in general, were captured almost exclusively in forested areas. An. cruzii, An. oswaldoi and An. fluminensis were captured more frequently in a residence area. However, Cx. quinquefasciatus was the only one truly eusynanthropic. An. cruzii and Ae. scapularis were captured feeding on blood inside and around the residence, indicating that both species, malaria and arbovirus vectors respectively, may be involved in the transmission of these such diseases in rural areas.
Full Text Available Background: Culex quinquefasciatus (Diptera: Culicidae is an important vector for many human diseases. The aim of this study was to evaluate the susceptibility level of larval and adult stages of Cu. quinquefasciatus to different groups of WHO recommended insecticides for vector control.Methods: Larval stages of the Culex mosquitoes were collected from their natural habitats in Rafsanjan County at Kerman Province, southeast of Iran in 2016. Insecticide susceptibility status of adult female Cx. quinquefasciatus against DDT (4%, deltamethrin (0.05%, malathion 5%, and bendiocarb (0.1% were determined using WHO standard insecticide susceptibility test. Additional test was carried out to determine the susceptibility status of larvae of Cx. quinquefasciatus to temephos. Bioassay data were analyzed by Probit program.Results: Cx. quinquefasciatus adults showed resistance to all four groups of the tested insecticides according to the WHO criteria for resistance evaluation. The lethal concentrations for 50% mortality (LC50 and 90% mortality (LC90 of temephos against Cx. quinquefasciatus larvae were 0.18mg/l and 0.78mg/l, respectively. This finding also confirms resistance to temephos based on the WHO recommended instructions for resistance evaluation.Conclusion: Resistance to all groups of the tested insecticides should be considered for future vector control investigations in the study area.
Bashir, Al; Hassan, A Abu; Salmah, M R Che; Rahman, W A
The efficacy of the larvicidal and pupicidal agent (Agnique) MMF was evaluated against larvae of An. arabiensis and Culex (Diptera: Culicidae) under field conditions in Bahary Locality, Khartoum, Sudan. At an applied dosage of 0.25 ml/m2, MMF resulted in 89.4, 79.8 and 88.2% reductions in L3-L4 instars An. arabiensis and 63.5% in Culex larvae (all stages) 24 to 72 hours post-treatment. Pupae were completely eliminated (100%) within 24 hours posttreatment. The earlier instars (L1-L2) of An. arabiensis were more tolerant with a 62.5% reduction at 72 hours post-treatment compared to (L3-L4) instars and pupae. At 7-days post-treatment Agnique gave a 57.5% reduction in L1-L2 and 92.6% in L3-L4 instar larvae of An. arabiensis and 57.3% and 86.4% in Culex larvae and pupae, respectively. We conclude that Agnique can perform effectively against L3-L4 instars and pupae of An. arabiensis for only 1 week, and 3 to 4 days against L1-L2 instars of Culex spp.
Jackson, B T; Stone, C M; Ebrahimi, B; Briët, O J T; Foster, W A
A large-scale mesocosm was constructed and tested for its effectiveness for use in experiments on behaviour, reproduction and adult survivorship in the Afrotropical malaria vector Anopheles gambiae s.s. Giles (Diptera: Culicidae) in temperate climates. The large space (82.69 m(3) ) allowed for semi-natural experiments that increased demand on a mosquito's energetic reserves in an environment of widely distributed resources. A one-piece prefabricated enclosure, made with white netting and vinyl, prevented the ingress of predators and the egress of mosquitoes. Daylight and white materials prompted the mosquitoes to seclude themselves in restricted daytime resting sites and allowed the easy collection of dead bodies so that daily mortality could be assessed accurately using a method that accounts for the loss of a proportion of bodies. Here, daily, age-dependent mortality rates of males and females were estimated using Bayesian Markov chain Monte Carlo simulation. In overnight experiments, mosquitoes successfully located plants and took sugar meals. A 3-week survival trial with a single cohort demonstrated successful mating, blood feeding, oviposition and long life. The relatively low cost of the mesocosm and the performance of the mosquitoes in it make it a viable option for any behavioural or ecological study of tropical mosquitoes in which space and seasonal cold are constraining factors. © 2014 The Royal Entomological Society.
Jackson, Bryan T.; Stone, Christopher M.; Ebrahimi, Babak; Briët, Olivier J.T.; Foster, Woodbridge A.
A large-scale mesocosm was constructed and tested for its effectiveness for experiments on behaviour, reproduction, and adult survivorship of the Afrotropical malaria vector Anopheles gambiae s.s. Giles (Diptera: Culicidae) in temperate climates. The large space (82.69 m3) allowed for semi-natural experiments that increased demand on a mosquito’s energetic reserves in an environment of widely distributed resources. A one-piece prefabricated enclosure, made with white netting and vinyl, prevented the ingress of predators and the egress of mosquitoes. Daylight and white materials prompted the mosquitoes to seclude themselves in restricted daytime resting sites and allowed easy collection of dead bodies so that daily mortality could be assessed accurately, using a method that accounts for a proportion of bodies being lost. Here, daily, age-dependent mortality rates of males and females were estimated using Bayesian Markov Chain Monte Carlo simulation. In overnight experiments, mosquitoes successfully located plants and took sugar meals. A 3-week survival trial with a single-cohort demonstrated successful mating, blood feeding, oviposition, and long life. The relatively low cost of the mesocosm and the performance of the mosquitoes in it make it a viable option for any behavioural or ecological study of tropical mosquitoes where space and seasonal cold are constraining factors. PMID:25294339
Alencar, Jeronimo; Marcondes, Carlos Brisola; Serra-Freire, Nicolau Maués; Lorosa, Elias Seixas; Pacheco, Juliana Barreto; Guimarães, Anthony Erico
We present the identification of bloodfeeding sources of Haemagogus (Haemagogus) capricornii Lutz and Haemagogus (Conopostegus) leucocelaenus (Dyar & Shannon) (Diptera: Culicidae) from different regions of Brazil, as analyzed by precipitin tests. Anti-sera for bird, bovine, equine, human, opossum, and rodent were used. Two hundred one mosquitoes were examined (147 Hg. leucocelaenus and 54 Hg. capricornii), of which 177 reacted for some anti-serum. For Hg. leucocelaenus, 86 (68.3%) reacted to one blood source, 38 (30.2%) to two sources, and two (1.6%) to three sources; the combinations of bird + human (18.4%), bird + rodent (15.8%), and bird + marsupial (15.8%) were the most frequent. For Hg. capricornii, 34 (66.7%) reacted to one blood source; combinations bird + rodent (37.5%) and bird + marsupial (25%) were the most frequent combinations. Mosquito preference for bloodfeeding sources was different in these areas, possibly because of the availability of sources. This diversity of sources can have important epidemiological implications.
Appadurai Daniel Reegan
Full Text Available Ecbolin A and ecbolin B were isolated from ethyl acetate extract of Ecbolium viride (Forsk. Alston root and evaluated for larvicidal and growth disturbance activities against Aedes aegypti L. (Diptera: Culicidae. For larvicidal activity, the third instar larvae of A. aegypti were exposed to different concentrations viz., 1.0, 2.5, 5.0 and 10 ppm for each compound. Among the two compounds screened, ecbolin B recorded highest larvicidal activity with LC50 and LC90 values of 0.70 and 1.42 ppm, respectively. In control, the larval behaviour was normal. The active compound ecbolin B was tested for growth disruption activity at sub lethal concentrations viz., 0.5, 1.0 ppm and observed for malformation like larval gut elongation, larval longevity, intermediates, malformed adults, failed adult emergence and compared with methoprene. The results showed significant level of larva–pupa intermediates, pupa–adult intermediates, malformed adult emergence and less adult formation against A. aegypti. The histopathological results revealed a severe damage on the midgut epithelial columnar cells (CC and cuboidal cells (CU in ecbolin B treated larvae of A. aegypti. Similarly peritrophic membrane (pM was also observed to be damaged in the treated larvae. The present results suggest that, ecbolin B could be used as a larvicidal agent against dengue vector A. aegypti.
Mogi, M; Armbruster, P A; Tuno, N; Aranda, C; Yong, H S
We compared climatic distribution ranges between Aedes albopictus (Skuse) (Diptera: Culicidae) and the five wild (nondomesticated) species of Albopictus Subgroup of Scutellaris Group of Aedes (Stegomyia) in southern Asia. Distribution sites of the wild species concentrate in seasonal forest and savannah climate zones in India, Indochina, and southern China. The distribution of Ae. albopictus is broader than the wild species under 1) tropical rain-forest climate, 2) steppe and temperate savannah climate, and 3) continental climate with large seasonal temperature variation (hot summer and cold winter) at temperate lowlands (northernmost sites 40°N in Ae. albopictus vs 32°N in the wild species). However, the distribution of Ae. albopictus is more limited at tropical and subtropical highlands where the climate is cool but less continental (small seasonal variation, mild summer, and winter). We discuss a possibility that the broader climate ranges of Ae. albopictus are ecological or eco-evolutionary consequences of adaptation to human habitats. We also propose a general scenario for the origin, dispersal, and adaptation of Ae. albopictus in Asia as a hypothesis for future research. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: email@example.com.
Unlu, Isik; Williams, Gregory M; Rochlin, Ilia; Suman, Devi; Wang, Yi; Chandel, Kshitij; Gaugler, Randy
Mosquito control programs in the United States are still searching for best management practices to control the Asian tiger mosquito, Aedes albopictus (Skuse; Diptera: Culicidae). Most intervention methods for this species are either labor intensive (e.g., source reduction) or short-term (e.g., ultra-low-volume adulticiding). We investigated the effectiveness of barrier spray pesticide applications within urban and suburban residential yards in New Jersey as a control strategy using a before-after-control-impact (BACI) approach. Applications of Demand CSR pyrethroid (9.7% AI lambda-cyhalothrin) only or combined Demand CSR and Archer IGR insect growth regulator (1.3% AI pyriproxyfen) applications resulted in significant and similar decreases in adult mosquito abundance post-treatment ranging from 78 to 74% respectively, compared with the untreated control. Both insecticides exceeded the 70% reduction threshold considered as effective for Ae. albopictus control for 2 to 4 wk. However, applications of Archer IGR alone did not reduce adult mosquito abundance. The field study results were supported by laboratory no-choice bioassays using treated leaf foliage. Our study is the first data driven evidence of the residual efficacy of barrier pesticide applications in New Jersey with lambda-cyhalothrin that provided significant reductions in adult Ae. albopictus populations for an extended duration.
Karla Rejane de Andrade Porto
Full Text Available Abstract: INTRODUCTION: Dengue fever is a viral disease transmitted by the Aedes aegypti Linn. (1792 (Diptera: Culicidae mosquito, which is endemic in several regions of Brazil. Alternative methods for the control of the vector include botanical insecticides, which offer advantages such as lower environmental contamination levels and less likelihood of resistant populations. Thus, in this study, the ability of botanical insecticide formulations to inhibit the activity of the liver enzymes serum cholinesterase and malate dehydrogenase was evaluated. METHODS: Inhibition profiles were assessed using in vitro assays for cholinesterase and malate dehydrogenase activity and quantitated by ultraviolet-visible spectroscopy at 410nm to 340nm. RESULTS Insecticide products formulated from cashew nutshell liquid [A] and ricinoleic acid [B] showed cholinesterase activity levels of 6.26IU/mL and 6.61IU/mL, respectively, while the control level for cholinesterase was 5-12IU/mL. The products did not affect the level of 0.44IU/mL established for malate dehydrogenase, as the levels produced by [A] and [B] were 0.43IU/mL and 0.45IU/mL, respectively. CONCLUSIONS Our findings show that in vitro testing of the formulated products at concentrations lethal to A. aegypti did not affect the activity of cholinesterase and malate dehydrogenase, indicating the safety of these products.
Porto, Karla Rejane de Andrade; Motti, Priscilla Rezende; Machado, Alexandre Alves; Roel, Antonia Railda
Dengue fever is a viral disease transmitted by the Aedes aegypti Linn. (1792) (Diptera: Culicidae) mosquito, which is endemic in several regions of Brazil. Alternative methods for the control of the vector include botanical insecticides, which offer advantages such as lower environmental contamination levels and less likelihood of resistant populations. Thus, in this study, the ability of botanical insecticide formulations to inhibit the activity of the liver enzymes serum cholinesterase and malate dehydrogenase was evaluated. Inhibition profiles were assessed using in vitro assays for cholinesterase and malate dehydrogenase activity and quantitated by ultraviolet-visible spectroscopy at 410nm to 340nm. Insecticide products formulated from cashew nutshell liquid [A] and ricinoleic acid [B] showed cholinesterase activity levels of 6.26IU/mL and 6.61IU/mL, respectively, while the control level for cholinesterase was 5-12IU/mL. The products did not affect the level of 0.44IU/mL established for malate dehydrogenase, as the levels produced by [A] and [B] were 0.43IU/mL and 0.45IU/mL, respectively. Our findings show that in vitro testing of the formulated products at concentrations lethal to A. aegypti did not affect the activity of cholinesterase and malate dehydrogenase, indicating the safety of these products.
Gerson A. Müller
Full Text Available Crepuscular activity of culicids (Diptera, Culicidae in the peridomicile and in the remaining riparian forest in Tibagi river, State of Paraná, Brazil. Human-attracted mosquitoes were collected for one hour, around sunset time (half hour before and half after, from April to December 2006, in two environments (riparian forest and near houses, in Tibagi river basin, Palmeira municipality, State of Paraná. Seven-hundred forty-nine mosquitoes, belonging to 13 species, were collected. Psorophora champerico Dyar & Knab, 1906 (42.86% and Psorophora discrucians (Walker, 1856 (40.59% were the most frequent species. No significant differences between quantities of Ps. champerico (t = -0.792; d.f. = 16; p = 0.43 and Ps. discrucians (t = 0.689; d.f. = 16; p = 0.49 obtained in riparian forest and near houses were observed, indicating similar conditions for crepuscular activity of these species in both environments. Psorophora champerico and Ps. discrucians responded (haematophagic activity to environmental stimuli associated with the twilight hours differently in distinct habitats studied. The former species is registered for the first time in the Atlantic forest biome.
Šebesta, Oldřich; Gelbič, Ivan; Minář, Jan
Roč. 7, č. 2 (2012), s. 288-298 ISSN 1895-104X R&D Projects: GA MŠk 2B08003 Institutional research plan: CEZ:AV0Z60930519; CEZ:AV0Z50070508 Keywords : Aedes vexans * Aedes sticticus * Culex modestus * Culex pipiens Subject RIV: EG - Zoology Impact factor: 0.818, year: 2012
Adriana Félix do Anjos
Full Text Available A alteração da paisagem natural pode gerar mudanças que favorecem odesenvolvimento e proliferação de determinadas espécies de Culicidae, em detrimento de outras que se deslocam para outros locais ou são extintas. Baseando-se nestas mudanças, algumas espécies podem ser utilizadas como bioindicadores do grau de degradação ambiental. O presente estudo tem como objetivo analisar a composição e riqueza deCulicidae, em dois ambientes em área de Floresta Atlântica, e avaliar se as espécies encontradas indicam o grau de preservação dos fragmentos estudados. As coletas foram realizadas em dois ambientes, denominados Carvalho e Trilha, em área de Floresta Atlântica(Mananciais da Serra, no Estado do Paraná - Brasil, nos meses de dezembro/2002 a maio/2003, utilizando-se um aspirador elétrico manual. Foram identificadas 48 espécies de 636 espécimes de Culicidae. A composição taxonômica e riqueza das espécies de Culicidaediferenciaram-se entre os ambientes estudados, provavelmente, influenciadas pelo estado de preservação dos fragmentos florestais. Os maiores valores de riqueza observados no Carvalho, assim como o predomínio das espécies da tribo Sabethini e Kerteszia sugeremreduzida ação antrópica neste fragmento florestal. De modo contrário, a composição das espécies e os menores valores de riqueza observadas na Trilha indicam grau alto de degradação ambiental.Modifications in the landscape can lead to the development and proliferation of some Culicidae species, in detriment of others. As a result, some species may be forced to move to other places or become locally extinct. Based on these changes, some species can beused as bioindicators of environmental degradation. The aim of this study was to assess Culicidae composition and richness in two Atlantic Forest sites (Carvalho and Trilha; State of Paraná, Brazil, and to evaluate whether they can be used as indicators of environmental degradation of these sites
Navarro, J.C.; Enríquez, S.; Campaña, Y.; Benítez Ortíz, W.
Two new records of Sabethes mosquitoes (Culicidae: Nematocera) are reported for Ecuador with the respective extension of their geographical distribution in the Neotropics: Sabethes intermedius Lutz and Sabethes soperi Lane & Cerqueira, from the provinces of Napo (Amazon) into the Natural Reserve of Colonso-Chalupas at 1,200 m altitude, beside Tena city, Ecuador. Both species are considered as potential vectors of sylvatic Yellow Fever virus and Mayaro virus. Information on collection local...
Gerson A. Müller
Full Text Available Crepuscular activity of culicids (Diptera, Culicidae in the peridomicile and in the remaining riparian forest in Tibagi river, State of Paraná, Brazil. Human-attracted mosquitoes were collected for one hour, around sunset time (half hour before and half after, from April to December 2006, in two environments (riparian forest and near houses, in Tibagi river basin, Palmeira municipality, State of Paraná. Seven-hundred forty-nine mosquitoes, belonging to 13 species, were collected. Psorophora champerico Dyar & Knab, 1906 (42.86% and Psorophora discrucians (Walker, 1856 (40.59% were the most frequent species. No significant differences between quantities of Ps. champerico (t = -0.792; d.f. = 16; p = 0.43 and Ps. discrucians (t = 0.689; d.f. = 16; p = 0.49 obtained in riparian forest and near houses were observed, indicating similar conditions for crepuscular activity of these species in both environments. Psorophora champerico and Ps. discrucians responded (haematophagic activity to environmental stimuli associated with the twilight hours differently in distinct habitats studied. The former species is registered for the first time in the Atlantic forest biome.Atividade crepuscular de culicídeos (Diptera, Culicidae no peridomicílio e remanescentes de matas ciliares do Rio Tibagi. Estado do Paraná, Brasil. Mosquitos atraídos por humanos foram coletados por uma hora em torno do crepúsculo vespertino (meia hora antes e meia hora depois, de abril a dezembro de 2006, em dois locais (mata ciliar e peridomicílio na bacia do Rio Tibagi, município de Palmeira, Estado do Paraná. Foram capturados 749 mosquitos distribuídos em 13 espécies. Psorophora champerico Dyar & Knab, 1906 (42,86% e Ps. discrucians (Walker, 1856 (40,59% foram as espécies mais freqüentes. Não foram registradas diferenças significativas entre as médias de indivíduos capturados entre os pontos de mata ciliar e peridomicílio para Ps. champerico (t = -0,792; g.l. = 16; p = 0
Hao, Huiling; Wei, Jianrong; Dai, Jianqing; Du, Jiawei
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.
Popko, David A; Henke, Jennifer A; Mullens, Bradley A; Walton, William E
Commercially available formulations of two entomopathogenic fungi, Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales: Clavicipitaceae) and Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitaceae), were assessed for control of Culex quinquefasciatus Say (Diptera: Culicidae) in underground storm drain systems (USDS) in the Coachella Valley of southern California. Each of three treatments, the two fungi or a water control, was applied to 1 m2 of vertical wall at eight USDS sites in spring and autumn of 2015. Fungal infectivity and lethality were assessed at 1 d and 1, 2, and 4 wk post-application. Overnight bioassays using adult lab-reared female mosquitoes were carried out on the treated USDS wall areas and then mosquitoes were held in the laboratory for up to 21 d to allow fungal infections to be expressed. Postmortem fungal sporulation was assessed up to 2 wk at 100% humidity. Mosquito-fungal interactions also were assessed in bioassays of the three treatments on filter paper exposed to USDS conditions during autumn. Metarhizium anisopliae killed mosquitoes faster than B. bassiana; nevertheless, both freshly applied formulations caused greater than 80% mortality. Fungal persistence declined significantly after 1 wk under USDS conditions, but some infectivity persisted for more than 4 wk. Beauveria bassiana was more effective against Cx. qinquefasciatus in the spring, while M. anisopliae was more effective in the cooler conditions during autumn. USDS environmental conditions (e.g., temperature, relative humidity, standing water) influenced fungal-related mortality and infection of Cx. quinquefasciatus. The utility of these fungal formulations for mosquito abatement in the Coachella Valley and implications for fungal control agents in USDS environments are discussed. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: firstname.lastname@example.org.
Encontro de Haemagogus (Conopostegus leucocelaenus (Diptera: Culicidae, no Município de Porto Alegre, Estado do Rio Grande do Sul Finding of Haemagogus (Conopostegus leucocelaenus (Diptera: Culicidae, in the municipality of Porto Alegre, State of Rio Grande do Sul
Almério de Castro Gomes
Full Text Available Em novembro de 2006, foi realizada uma investigação entomológica numa mata nativa do município de Porto Alegre, Estado do Rio Grande do Sul. O resultado foi a captura de várias espécies Culicidae, incluindo o primeiro registro da presença de Haemagogus leucocelaenus na localidade. Esta espécie é considerada vetora do vírus da febre amarela em alguns municípios do Estado, motivando esta comunicação para alertar sobre o potencial da área para circulação do agente etiológico desta doença.In November 2006, an entomological investigation was carried out in a native forest in the municipality of Porto Alegre, State of Rio Grande do Sul. The result was the capture of several Culicidae species, including the first recording of the presence of Haemagogus leucocelaenus in this locality. This species is considered to be a vector for the yellow fever virus in some municipalities of this State, and this was the motivation for the present communication, in order to warn regarding the potential of this area for circulation of the etiological agent for this disease.
Nikookar, Seyed Hassan; Azari-Hamidian, Shahyad; Fazeli-Dinan, Mahmoud; Nasab, Seyed Nouraddin Mousavi; Aarabi, Mohsen; Ziapour, Seyyed Payman; Enayati, Ahmadali
Although considerable progress has been made in the past years in management of mosquito borne diseases such as malaria, dengue, yellow fever and West Nile fever through research in biology and ecology of the vectors, these diseases are still major threats to human health. Therefore, more research is required for better management of the diseases. This investigation provides information on the composition, co-occurrence, association and affinity indices of mosquito larvae in Mazandaran Province, northern Iran. In a large scale field study, mosquito larvae were collected from 120 sentinel sites in 16 counties in Mazandaran Province, using standard 350 ml dipper. Sampling took place monthly from May to December 2014. Collected larvae were mounted on glass slides using de Faure's medium and were diagnosed using morphological characters. Totally, 19,840 larvae were collected including three genera and 16 species from 120 larval habitats, as follows: Anopheles claviger, Anopheles hyrcanus, Anopheles maculipennis s.l., Anopheles marteri, Anopheles plumbeus, Anopheles pseudopictus, Culex pipiens, Culex tritaeniorhynchus, Culex torrentium, Culex perexiguus, Culex territans, Culex mimeticus, Culex hortensis, Culiseta annulata, Culiseta longiareolata, and Culiseta morsitans. Predominant species were Cx. pipiens and An. maculipennis s.l. which show the highest co-occurrence. The pair of species An. hyrcanus/An. pseudopictus showed significant affinity and association. High co-occurrence of the predominant species Cx. pipiens and An. maculipennis s.l. in the study area is of considerable importance in terms of vector ecology. It was also revealed that An. pseudopictus/An. hyrcanus often occur sympatrically indicating their common habitat requirements. The information may be equally important when vector control measures are considered. Copyright © 2016 Elsevier B.V. All rights reserved.
An experiment to intercross geographic population of Cp fatigans from Medan (M), North Sumatra, Jakarta (J), Municipality of Jakarta, Java, Den Pasar (B), Bali, Menado (Mo), North Sulawesi, and Kupang (K), and South East Indonesia, has been done. The criterium for the determination of the degree of success in the matings is the relative amount of the male semen present in the female body transfered during copulation. The relative amount of the male semen in the females can be measured by counting the activity of the female body that already receives the transfered semen and the accompanying secretion of the accessory glands from the males, as the males are previously treated with the radioisotope P32 when they are still at the fourth instar larval stage. It proves that all population are able to be intercrossed, and that: 1. All population as source of females show no significant differences in their capability of mating, although there are light deviations from complete similarities among them. 2. All population as source of males are able to be intercrossed with some significant differences. Their respective values as males vary which, in descending order, can be arranged as M, J, B, K, and Mo. 3. Even the population in question are intercrossable, yet the result of their mutual intermatings cannot be assured as being proportionally viable. (author)
Turell, M. J; Mores, C. N; Dohm, D. J; Komilov, N; Paragas, J; Lee, J. S; Shermuhemedova, D; Endy, T. P; Kodirov, A; Khodjaev, S
... (family Flaviviridae, genus Flavivirus, WNV) viruses under laboratory conditions. These molestus were highly competent laboratory vectors of WNV, with infection and dissemination rates of 96 and 81%, respectively. Approximately 75...
Full Text Available Abstract Background Although malaria disappeared from southern France more than 60 years ago, suspicions of recent autochthonous transmission in the French Mediterranean coast support the idea that the area could still be subject to malaria transmission. The main potential vector of malaria in the Camargue area, the largest river delta in southern France, is the mosquito Anopheles hyrcanus (Diptera: Culicidae. In the context of recent climatic and landscape changes, the evaluation of the risk of emergence or re-emergence of such a major disease is of great importance in Europe. When assessing the risk of emergence of vector-borne diseases, it is crucial to be able to characterize the arthropod vector's spatial distribution. Given that remote sensing techniques can describe some of the environmental parameters which drive this distribution, satellite imagery or aerial photographs could be used for vector mapping. Results In this study, we propose a method to map larval and adult populations of An. hyrcanus based on environmental indices derived from high spatial resolution imagery. The analysis of the link between entomological field data on An. hyrcanus larvae and environmental indices (biotopes, distance to the nearest main productive breeding sites of this species i.e., rice fields led to the definition of a larval index, defined as the probability of observing An. hyrcanus larvae in a given site at least once over a year. Independent accuracy assessments showed a good agreement between observed and predicted values (sensitivity and specificity of the logistic regression model being 0.76 and 0.78, respectively. An adult index was derived from the larval index by averaging the larval index within a buffer around the trap location. This index was highly correlated with observed adult abundance values (Pearson r = 0.97, p An. hyrcanus larval and adult populations from the landscape indices. Conclusion This work shows that it is possible to use
Ovicidal, larvicidal and adulticidal properties of Asparagus racemosus (Willd.) (Family: Asparagaceae) root extracts against filariasis (Culex quinquefasciatus), dengue (Aedes aegypti) and malaria (Anopheles stephensi) vector mosquitoes (Diptera: Culicidae).
Govindarajan, Marimuthu; Sivakumar, Rajamohan
Several diseases are associated to the mosquito-human interaction. Mosquitoes are the carriers of severe and well-known illnesses such as malaria, arboviral encephalitis, dengue fever, chikungunya fever, West Nile virus and yellow fever. These diseases produce significant morbidity and mortality in humans and livestock around the world. The present investigation was undertaken to study the ovicidal, larvicidal and adulticidal activities of crude hexane, ethyl acetate, benzene, chloroform and methanol extracts of root of Asparagus racemosus were assayed for their toxicity against three important vector mosquitoes, viz., Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi (Diptera: Culicidae). The mean percent hatchability of the eggs was observed after 48 h post-treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. All the five solvent extracts showed moderate ovicidal activity; however, the methanol extract showed the highest ovicidal activity. The methanol extract of Asparagus racemosus against Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi exerted 100% mortality (zero hatchability) at 375, 300 and 225 ppm, respectively. Control eggs showed 99-100% hatchability. The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in methanol extract of root of Asparagus racemosus against the larvae of Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi with the LC50 and LC90 values were 115.13, 97.71 and 90.97 ppm and 210.96, 179.92, and 168.82 ppm, respectively. The adult mortality was observed after 24 h recovery period. The plant crude extracts showed dose-dependent mortality. At higher concentrations, the adult showed restless movement for some times with abnormal wagging and then died. Among the extracts tested, the highest adulticidal activity was observed in
Dandalo, Leonard C; Brooke, Basil D; Munhenga, Givemore; Lobb, Leanne N; Zikhali, Jabulani; Ngxongo, Sifiso P; Zikhali, Phineas M; Msimang, Sipho; Wood, Oliver R; Mofokeng, Mohlominyana; Misiani, Eunice; Chirwa, Tobias; Koekemoer, Lizette L
Anopheles arabiensis (Patton; Diptera: Culicidae) is a major malaria vector in the southern African region. In South Africa, effective control of this species using indoor-based interventions is reduced owing to its tendency to rest outdoors. As South Africa moves towards malaria elimination there is a need for complementary vector control strategies. One of the methods under consideration is the use of the sterile insect technique (SIT). Key to the successful implementation of an SIT programme is prior knowledge of the size and spatial distribution of the target population. Understanding mosquito population dynamics for both males and females is critical for efficient programme implementation. It is thus necessary to use outdoor-based population monitoring tools capable of sampling both sexes of the target population. In this project mosquito surveillance and evaluation of tools capable of collecting both genders were carried out at Mamfene in northern KwaZulu-Natal Province, South Africa, during the period January 2014 to December 2015. Outdoor- and indoor-resting Anopheles mosquitoes were sampled in three sections of Mamfene over the 2-yr sampling period using modified plastic buckets, clay pots and window exit traps. Morphological and molecular techniques were used for species identifications of all samples. Wild-caught adult females were tested for Plasmodium falciparum (Welch; Haemosporida: Plasmodiidae) infectivity. Out of 1,705 mosquitoes collected, 1,259 (73.8%) and 255 (15%) were identified as members of either the Anopheles gambiae complex or Anopheles funestus group respectively. An. arabiensis was the most abundant species contributing 78.8% of identified specimens. Mosquito density was highest in summer and lowest during winter. Clay pots yielded 16.3 mosquitoes per trap compared to 10.5 for modified plastic buckets over the 2-yr sampling period. P. falciparum infection rates for An. arabiensis were 0.7% and 0.5% for 2014 and 2015, respectively
Richards, Stephanie L; Ponnusamy, Loganathan; Unnasch, Thomas R; Hassan, Hassan K; Apperson, Charles S
Aedes albopictus (Skuse) (Diptera: Culicidae) is a major nuisance mosquito and a potential arbovirus vector. The host-feeding patterns of Ae. albopictus were investigated during the 2002 and 2003 mosquito seasons in suburban neighborhoods in Wake County, Raleigh, NC. Hosts of blood-fed Ae. albopictus (n = 1,094) were identified with an indirect enzyme-linked immunosorbent assay, by using antisera made in New Zealand White rabbits to the sera of animals that would commonly occur in peridomestic habitats. Ae. albopictus fed predominantly on mammalian hosts (83%). Common mammalian hosts included humans (24%), cats (21%), and dogs (14%). However, a notable proportion (7%) of bloodmeals also was taken from avian hosts. Some bloodmeals taken from birds were identified to species by a polymerase chain reaction-heteroduplex assay (PCR-HDA). Ae. albopictus fed predominantly on chickens and a northern cardinal. PCR-HDA failed to produce detectable products for 29 (58%) of 50 bloodmeals for which DNA had been amplified, indicating that these mosquitoes took mixed bloodmeals from avian and nonavian hosts. Ae. albopictus preference for humans, dogs, and cats was determined by calculating host-feeding indices for the three host pairs based on the proportion of host specific blood-fed mosquitoes collected in relation to the number of specific hosts per residence as established by a door-to-door survey conducted in 2003. Estimates of the average amount of time that residents and their pets (cats and dogs) spent out of doors were obtained. Host-feeding indices based only on host abundance indicated that Ae. albopictus was more likely to feed on domestic animals. However, when feeding indices were time-weighted, Ae. albopictus fed preferentially upon humans. Ae. albopictus blood feeding on humans was investigated using a STR/PCR-DNA profiling technique that involved amplification of three short tandem repeats loci. Of 40 human bloodmeals, 32 (80%) were from a single human, whereas
Okech, Bernard; Arai, Meiji; Matsuoka, Hiroyuki
Xanthurenic acid (XA), produced as a byproduct during the biosynthesis of insect eye pigment (ommochromes), is a strong inducer of Plasmodium gametogenesis at very low concentrations. In previous studies, it was shown that XA is present in Anopheles stephensi (Diptera: Culicidae) mosquito salivary glands and that during blood feeding the mosquitoes ingested their own saliva into the midgut. Considering these two facts together, it is therefore likely that XA is discharged with saliva during blood feeding and is swallowed into the midgut where it exerts its effect on Plasmodium gametocytes. However, the quantities of XA in the salivary glands and midgut are unknown. In this study, we used high performance liquid chromatography with electrochemical detection to detect and quantify XA in the salivary glands and midgut. Based on the results of this study, we found 0.28+/-0.05 ng of XA in the salivary glands of the mosquitoes, accounting for 10% of the total XA content in the mosquito whole body. The amounts of XA in the salivary glands reduced to 0.13+/-0.06 ng after mosquitoes ingested a blood meal. Approximately 0.05+/-0.01 ng of XA was detected in the midgut of nonblood fed An. stephensi mosquitoes. By adding synthetic tryptophan as a source of XA into larval rearing water (2 mM) or in sugar meals (10 mM), we evaluated whether XA levels in the mosquito (salivary glands, midgut, and whole body) were boosted and the subsequent effect on infectivity of Plasmodium berghei in the treated mosquito groups. A female specific increase in XA content was observed in the whole body and in the midgut of mosquito groups where tryptophan was added either in the larval water or sugar meals. However, XA in the salivary glands was not affected by tryptophan addition to larval water, and surprisingly it reduced when tryptophan was added to sugar meals. The P. berghei oocyst loads in the mosquito midguts were lower in mosquitoes fed tryptophan treated sugar meals than in mosquitoes
Suresh, Udaiyan; Murugan, Kadarkarai; Benelli, Giovanni; Nicoletti, Marcello; Barnard, Donald R; Panneerselvam, Chellasamy; Kumar, Palanisamy Mahesh; Subramaniam, Jayapal; Dinesh, Devakumar; Chandramohan, Balamurugan
Mosquitoes are vectors of devastating pathogens and parasites, causing millions of deaths every year. Dengue is a mosquito-borne viral infection found in tropical and subtropical regions around the world. Recently, transmission has strongly increased in urban and semiurban areas, becoming a major international public health concern. Aedes aegypti (Diptera: Culicidae) is the primary vector of dengue. The use of synthetic insecticides to control Aedes mosquitoes lead to high operational costs and adverse nontarget effects. In this scenario, eco-friendly control tools are a priority. We proposed a novel method to synthesize silver nanoparticles using the aqueous leaf extract of Phyllanthus niruri, a cheap and nontoxic material. The UV-vis spectrum of the aqueous medium containing silver nanostructures showed a peak at 420 nm corresponding to the surface plasmon resonance band of nanoparticles. SEM analyses of the synthesized nanoparticles showed a mean size of 30-60 nm. EDX spectrum showed the chemical composition of the synthesized nanoparticles. XRD highlighted that the nanoparticles are crystalline in nature with face-centered cubic geometry. Fourier transform infrared spectroscopy (FTIR) of nanoparticles exhibited prominent peaks 3,327.63, 2,125.87, 1,637.89, 644.35, 597.41, and 554.63 cm(-1). In laboratory assays, the aqueous extract of P. niruri was toxic against larval instars (I-IV) and pupae of A. aegypti. LC50 was 158.24 ppm (I), 183.20 ppm (II), 210.53 ppm (III), 210.53 ppm (IV), and 358.08 ppm (pupae). P. niruri-synthesized nanoparticles were highly effective against A. aegypti, with LC50 of 3.90 ppm (I), 5.01 ppm (II), 6.2 ppm (III), 8.9 ppm (IV), and 13.04 ppm (pupae). In the field, the application of silver nanoparticles (10 × LC50) lead to A. aegypti larval reduction of 47.6%, 76.7% and 100%, after 24, 48, and 72 h, while the P. niruri extract lead to 39.9%, 69.2 % and 100 % of reduction, respectively. In adulticidal experiments, P. niruri extract
Abella-Medrano, Carlos Antonio; Ibáñez-Bernal, Sergio; MacGregor-Fors, Ian; Santiago-Alarcon, Diego
Land-use change has led to a dramatic decrease in total forest cover, contributing to biodiversity loss and changes of ecosystems' functions. Insect communities of medical importance can be favored by anthropogenic alterations, increasing the risk of novel zoonotic diseases. The response of mosquito (Diptera: Culicidae) abundance and richness to five land-use types (shade coffee plantation, cattle field, urban forest, peri-urban forest, well-preserved montane cloud forest) and three seasons ("dry", "rainy" and "cold") embedded in a neotropical montane cloud forest landscape was evaluated. Standardized collections were performed using 8 CDC miniature black-light traps, baited with CO2 throughout the year. Generalized additive mixed models were used to describe the seasonal and spatial trends of both species richness and abundance. Rank abundance curves and ANCOVAs were used to detect changes in the spatial and temporal structure of the mosquito assemblage. Two cluster analyses were conducted, using 1-βsim and the Morisita-Horn index to evaluate species composition shifts based on incidences and abundances. A total of 2536 adult mosquitoes were collected, belonging to 9 genera and 10 species; the dominant species in the study were: Aedes quadrivittatus, Wyeomyia adelpha, Wy. arthrostigma, and Culex restuans. Highest richness was recorded in the dry season, whereas higher abundance was detected during the rainy season. The urban forest had the highest species richness (n = 7) when compared to all other sites. Species composition cluster analyses show that there is a high degree of similarity in species numbers across sites and seasons throughout the year. However, when considering the abundance of such species, the well-preserved montane cloud forest showed significantly higher abundance. Moreover, the urban forest is only 30 % similar to other sites in terms of species abundances, indicating a possible isolating role of the urban environment. Mosquito
Cetin, Huseyin; Dechant, Peter; Yanikoglu, Atila
Efficacy of tank mixtures of commercial Bacillus thuringiensis subsp. israelensis (Bti) and Bacillus sphaericus (Bs) water-dispersable granule (WDG) formulations was evaluated in septic tanks, against Culex pipiens L. (Diptera: Culicidae) larvae. VectoLex WDG (Bs) + VectoBac WDG (Bti) were evaluated at various ratios from 488 g/ha VectoLex + 250 g/ha VectoBac up to 3,000 g/ha of each. All applications and ratios delivering VectoLex WDG at a rate equal to or greater than 988 g/ha provided more than 90% control for 28 days after treatment. The lowest dose provided this level of control for at least 7 days after treatment, with greater than 80% control after 2 wk. These results suggest that a retreatment interval of 2 wk is recommended with the lowest dose and retreatment intervals of 4 or more wk are recommended with the doses equal to or higher than 988 g/ha VectoLex + 250 g/ha VectoBac.
Bromeliad-associated mosquitoes from Atlantic forest in Santa Catarina Island, southern Brazil (Diptera, Culicidae, with new records for the State of Santa Catarina Mosquitos associados a bromélias em Mata Atlântica na Ilha de Santa Catarina, sul do Brasil (Diptera, Culicidae, com novos registros para o Estado de Santa Catarina
Gerson Azulim Müller
Full Text Available Bromeliad-associated mosquitoes (Diptera: Culicidae in Atlantic Forest in Florianópolis, Santa Catarina, southern Brazil, were studied, examining plants of Vriesea philippocoburgi Wawra and Aechmea lindenii (E. Morren Baker var. lindenii at secondary Atlantic rain forest, and A. lindenii and Vriesea friburgensis Mez var. paludosa (L. B. Smith at "restinga" per month, during 12 months. No immature forms of mosquitoes were collected from A. lindenii in the secondary forest. Collections obtained 368 immature mosquitoes, none of them from A. lindenii from rain forest. Culex (Microculex spp. constituted 79.8% of the total, Wyeomyia (Phoniomyia spp. 17.93%, and Anopheles (Kerteszia cruzii (Dyar & Knab, 1908 only 1.36%. The study shows the great predominance of species of medical importance not yet proved, and the small number of immature stages of anopheline mosquitoes. The rainfall, but not the mean temperatures, significantly influenced the quantity of mosquitoes from V. philippocoburgi. Significant differences between the quantities of immature forms of all the bromeliad species were found, and the shape of the plants could be important to the abundance of mosquitoes. All six species of Cx. (Microculex found are recorded for the first time in the State of Santa Catarina, and all six species of Wyeomyia (Phoniomyia are recorded for the first time in bromeliads in this state.Mosquitos (Diptera: Culicidae associados a bromélias em Mata Atlântica na Ilha de Santa Catarina, no Estado de Santa Catarina, foram estudados. Foram examinadas mensalmente plantas de Vriesea philippocoburgi Wawra e Aechmea lindenii (E. Morren Baker var. lindenii de floresta atlântica pluvial ombrófila e A. lindenii e Vriesea friburgensis Mez var. paludosa (L. B. Smith de restinga, durante 12 meses. As coletas resultaram em 368 formas imaturas de mosquitos, sendo que nenhuma foi coletada em A. lindenii de mata ombrófila. Culex (Microculex spp. constituíram 79,8% do total
Rueda-Páramo, M E; Montalva, C; Arruda, W; Fernandes, É K K; Luz, C; Humber, R A
A project from 2013 to 2017 sought to discover pathogenic fungi and oomycetes from dipteran species that are vectors of major diseases of humans and animals in central Brazil and to begin evaluating the potential of these pathogens as potential biological control agents concentrated on mosquito larvae. Some collecting sites proved to be especially productive for pathogens of naturally occurring mosquito species and for placements of healthy sentinel larvae of Aedes aegypti in various sorts of containers in a gallery forest in the Santa Branca Ecoturismo Private Reserve of Natural Patrimony (RPPN) near Terezópolis de Goiás (GO). Collections during May-April of 2016 and February 2017 yielded a few dead mosquito larvae of an undetermined Onirion sp. (Culicidae: Sabethini) whose hemocoels contained many ovoid, thick-walled, yellow-golden to golden-brown, ovoid thick-walled resistant sporangia, 38.3±4×22.8±2.3µm, decorated by numerous, closely and randomly spaced punctations of variable size and shape. These were the first indisputable collections from Brazil of any Coelomomyces species. Comparisons of the morphology of these sporangia with those of other species of Coelomomyces, confirmed that this Brazilian fungus represented a new species that is described here as Coelomomyces santabrancae. Copyright © 2017. Published by Elsevier Inc.
Marques Tatiani C
Full Text Available Abstract Background The most substantial and best preserved area of Atlantic Forest is within the biogeographical sub-region of Serra do Mar. The topographic complexity of the region creates a diverse array of microclimates, which can affect species distribution and diversity inside the forest. Given that Atlantic Forest includes highly heterogeneous environments, a diverse and medically important Culicidae assemblage, and possible species co-occurrence, we evaluated mosquito assemblages from bromeliad phytotelmata in Serra do Mar (southeastern Brazil. Methods Larvae and pupae were collected monthly from Nidularium and Vriesea bromeliads between July 2008 and June 2009. Collection sites were divided into landscape categories (lowland, hillslope and hilltop based on elevation and slope. Correlations between bromeliad mosquito assemblage and environmental variables were assessed using multivariate redundancy analysis. Differences in species diversity between bromeliads within each category of elevation were explored using the Renyi diversity index. Univariate binary logistic regression analyses were used to assess species co-occurrence. Results A total of 2,024 mosquitoes belonging to 22 species were collected. Landscape categories (pseudo-F value = 1.89, p = 0.04, bromeliad water volume (pseudo-F = 2.99, p = 0.03 and bromeliad fullness (Pseudo-F = 4.47, p An. homunculus was associated with Cx. ocellatus and the presence of An. cruzii was associated with Cx. neglectus, Cx. inimitabilis fuscatus and Cx. worontzowi. Anopheles cruzii and An. homunculus were taken from the same bromeliad, however, the co-occurrence between those two species was not statistically significant. Conclusions One of the main findings of our study was that differences in species among mosquito assemblages were influenced by landscape characteristics. The bromeliad factor that influenced mosquito abundance and assemblage structure was fullness. The findings of the current
Chordas, Stephen W.; Hudson, Patrick L.; Chapman, Eric G.
The dipteran fauna of Arkansas is generally poorly known. A previous study of the Aquatic macroinvertebrates of the White River National Wildlife Refuge, the largest refuge in Arkansas, reported only 12 diptera taxa out of 219 taxa collected (Chordas et al., 1996). Most of the dipterans from this study were identified only to the family level. The family Chironomidae is a large, diverse group and was predicted to be much more diverse in the refuge than indicated by previous studies. In this study, Chironomidae were targeted, with other aquatic or semiaquatic dipterans also retained, in collections designed to better define the dipteran fauna of the White River National Wildlife Refuge. Adult dipterans were collected from 22 sites within the refuge using sweep-nets, two types of blacklight traps, and lighted fan traps in June of 2001. Specimens from previous studies were retrieved and identified to the lowest possible taxonomic level. A total of 4,917 specimens representing 122 taxa was collected. The 122 taxa were comprised of the following: two chaoborids, 83 chironomids, 15 culicids, nine tabanids, and 13 tipulids. Of these, 46 species are new state records for Arkansas. Nine undescribed species of chironomids were collected, and eight species records represent significant range extensions.
Full Text Available Anopheles aquasalis es considerado como el principal vector de malaria humana en el norte de Venezuela. El estudio longitudinal se llevó a cabo en áreas costeras de la Península de Paria, estado Sucre. El hábitat de las larvas de A. aquasalis fue clasificado como: manglar salobre y pantano herbáceo. Muestreos para recolectar larvas de mosquitos e insectos asociados se realizaron mensualmente en ambos criaderos desde enero hasta diciembre de 1999 (30 muestras. Simultáneamente se midieron cinco variables seleccionadas del agua: conductividad, salinidad, oxígeno disuelto, temperatura y pH. En ambos criaderos de determinaron las variaciones estacionales y temporales de las larvas de A. aquasalis e insectos acuáticos. Para el período de estudio, la abundancia de larvas fue mayor en el manglar. El análisis de correspondencia mostró una fuerte relación entre algunos factores químicos del agua y la abundancia de las larvas. La abundancia de las larvas de A. aquasalis en ambas épocas, se correlacionó positivamente con la salinidad del agua, pH y conductividad, y negativamente con el oxígeno disuelto, en la estación seca. La presencia de larvas se correlacionó positivamente con la presencia de Avicennia germinans. En el manglar existió una asociación positiva entre la abundancia de larvas y la abundancia de la familia Scirtidae y una correlación negativa entre la abundancia de larvas y la precipitación mensual (Spearman, así como una correlación negativa significativa entre la abundancia de Gerridae y la precipitación mensual. En el pantano herbáceo, no había asociaciones significativas entre la abundancia de las larvas de A. aquasalis y la abundancia de otros insectos acuáticos asociados al hábitat.Larval seasonality of the mosquito Anopheles aquasalis (Diptera: Culicidae and other insects associated to its habitat in Sucre, Venezuela. Anopheles aquasalis Curry is considered the main vector of human malaria in Northern
María V Micieli
Full Text Available Se realizó un estudio de la variación estacional de una población de estadios inmaduros de A. aegypti en La Plata, Argentina, durante cuatro años. Se colocaron 36 recipientes plásticos con 700 ml de agua declorinada y se agregó, en cada uno, una tira de papel de filtro rodeando el perímetro interno como sitio para la ovipostura. Los huevos, larvas y pupas se cuantificaron semanalmente desde septiembre de 1996 hasta agosto de 2000. Tras cuantificar el número de huevos, los papeles fueron sumergidos en cada recipiente para facilitar la eclosión y se agregó un nuevo papel. La presencia de estados inmaduros de A. aegypti fue registrada desde diciembre-enero hasta junio durante los cuatro años de estudio. En 1997 se registraron 13 105 huevos, 7 978 larvas y 1 476 pupas con un 54.7 % de recipientes positivos; en 1998, 8 194 huevos, 668 larvas y 142 pupas y un 28.3 % de recipientes positivos para este mosquito. En 1999 se obtuvieron 13 510 huevos, 3 690 larvas y 743 pupas y un 56.7 % de recipientes con A. aegypti. Para el año 2000 se registraron 16 327 huevos, 4 669 larvas y 715 pupas y un porcentaje de recipientes positivos de 59.3 %. El número de huevos y el porcentaje de eclosión se redujo drásticamente en 1998 donde las temperaturas durante el período diciembre-mayo fueron entre uno y 2.5 ºC más bajas que durante los otros tres años de estudio. Estas temperaturas menores fueron consecuencia del fenómeno climático corriente El Niño.Population dynamics of the immature stages of Aedes aegypti (Diptera: Culicidae, vector of dengue: a longitudinal study (1996-2000. A four year study was conducted on a natural population of immature stages of Aedes aegypti after the re-invasion of Argentina by this vector in 1987. Thirty six plastic containers with 700 ml of dechlorinated water were placed in the La Plata Zoological Garden, La Plata, Argentina. A strip of filter paper around each container was added to facilitate egg counting. Eggs
Melandri, Vanessa; Alencar, Jerônimo; Guimarães, Anthony Érico
Bioecological aspects of anophelines (Diptera: Culicidae) near areas under the direct influence of the hydroelectric plant reservoir of Serra da Mesa in Goiás, Brazil, were analyzed. Samples were collected at the surrounding dam area during the phases before and after reservoir impoundment. The influence of climatic and environmental factors on the occurrence of Anopheles darlingi, Anopheles albitarsis, Anopheles triannulatus, Anopheles oswaldoi and Anopheles evansae was assessed using Pearson's correlations with indicators for richness and diversity as well as the index of species abundance (ISA) and the standardized index of species abundance (SISA). The highest anopheline density occurred during the phase after filling the tank; however, no direct correlation with the climatic factors was observed during this stage. The reservoir formation determined the incidence of the anopheline species. An. darlingi was the predominant species (SISA = 1.00). The significant difference (p < 0.05) observed between the species incidence during the different reservoir phases demonstrates the environmental effect of the reservoir on anophelines.
Spatial clustering and longitudinal variation of Anopheles darlingi (Diptera: Culicidae) larvae in a river of the Amazon: the importance of the forest fringe and of obstructions to flow in frontier malaria.
Barros, F S M; Arruda, M E; Gurgel, H C; Honório, N A
Deforestation has been linked to a rise in malaria prevalence. In this paper, we studied longitudinally 20 spots, including forested and deforested portions of a temporary river in a malarigenous frontier zone. Larval habitat parameters influencing distribution of Anopheles darlingi (Diptera: Culicidae) larvae were studied. We observed that larvae were clustered in forested-deforested transitions. For the first time in the literature, it was verified that parameters determining larval distribution varied from deforested to forested areas. The proximity to human dwellings was also a significant factor determining distribution, but larvae was most importantly associated with a previously undescribed parameter, the presence of small obstructions to river flow, such as tree trunks within the river channel, which caused pooling of water during the dry season ('microdams'). In deforested areas, the most important factor determining distribution of larvae was shade (reduced luminance). Larvae were absent in the entire studied area during the wet season and present in most sites during the dry season. During the wet-dry transition, larvae were found sooner in areas with microdams, than in other areas, suggesting that flow obstruction prolongs the breeding season of An. darlingi. Adult mosquito densities and malaria incidence were higher during the dry season. Our data correlate well with the published literature, including the distribution of malaria cases near the forest fringes, and has permitted the creation of a model of An. darlingi breeding, where preference for sites with reduced luminance, human presence and microdams would interact to determine larval distribution.
Ecological characterisation and infection of Anophelines (Diptera: Culicidae) of the Atlantic Forest in the southeast of Brazil over a 10 year period: has the behaviour of the autochthonous malaria vector changed?
Buery, Julyana Cerqueira; Rezende, Helder Ricas; Natal, Licia; Silva, Leonardo Santana da; Menezes, Regiane Maria Tironi de; Fux, Blima; Malafronte, Rosely Dos Santos; Falqueto, Aloisio; Cerutti Junior, Crispim
BACKGROUND In southeastern Brazil, autochthonous cases of malaria can be found near Atlantic Forest fragments. Because the transmission cycle has not been completely clarified, the behaviour of the possible vectors in those regions must be observed. A study concerning the entomological aspects and natural infection of anophelines (Diptera: Culicidae) captured in the municipalities of the mountainous region of Espírito Santo state was performed in 2004 and 2005. Similarly, between 2014 and 2015, 12 monthly collections were performed at the same area of the study mentioned above. METHODS Center for Disease Control (CDC) light traps with CO2 were set in open areas, at the edge and inside of the forest (canopy and ground), whereas Shannon traps were set on the edge. FINDINGS A total of 1,414 anophelines were collected from 13 species. Anopheles (Kerteszia) cruzii Dyar and Knab remained the most frequently captured species in the CDC traps set in the forest canopy, as well as being the vector with the highest prevalence of Plasmodium vivax/simium infection, according to molecular polymerase chain reaction techniques. CONCLUSIONS P. vivax/simium was found only in abdomens of the mosquitoes of the subgenus Nyssorhynchus, weakening the hypothesis that this subgenus also plays a role in malaria transmission in this specific region.
Maiduguri, Nigeria, were studied between January and June 2002. Dipteran samples were collected every 2 weeks from five different stations. Five groups of diptera organisms simulidae, chironomidae, centrapogo nidae, culicidae and chaoboridae were found in analyzable numbers. The diptera assemblage was ...
Alfonso Arturo Miranda H
Full Text Available La primera línea celular de Aedes aegypti fue establecida por Grace en 1966 y desde entonces se han utilizado para el estudio de virus, bacterias y parásitos. En el presente trabajo se describen, por primera vez, algunas características citoquímicas de los cultivos celulares de A. aegypti, infectados con la cepa (MHOM/CO/87CL412 de Leishmania panamensis. También se realizó un estudio morfológico de las células del cultivo. Se observaron 30 células pequeñas con apariencia fibrolastoide de 10.84±2.54 µm de largo y 5.31±1.26 µm de ancho; otras 30 presentaron apariencia epitelioide con 23.04±4.00 µm de largo y 13.96±3.70 µm de ancho; éstas últimas predominaron sobre las de apariencia fibroblastoide. De 113 células, un 7.08%, presentaron abundantes gránulos citoplasmáticos positivos con la coloración de PAS, indicando presencia de polisacáridos. La prueba de peroxidasa dio un resultado negativo. El mayor porcentaje de infección (18.90%, de un total de 101 células, se presentó el día 6. Ultraestructuralmente, las células presentaron un citoplasma con aspecto vacuolado; algunas contenían parásitos, otras material fibrilar y otras estaban vacías. Los resultados indican que los cultivos celulares de A. aegypti pueden ser infectados por L. panamensis y mantener dicho proceso por aproximadamente una semana.Morphology and cytochemistry of Aedes aegypti’s cell cultures (Diptera: Culicidae and susceptibility to Leishmania panamensis (Kinetoplastida: Trypanosomatidae. The first cellular line of Aedes aegypti was developed by Grace in 1966; afterwards, other cellular lines of this species have been generated. These have been used for the study of pathogenic organisms like viruses, bacteria and parasites, which demonstrates their importance in biomedical applications. This research describes, for the first time, some cytochemical characteristics of A. aegypti cell cultures, that were infected with (MHOM/CO/87CL412 strain of
Silva Heloisa Helena Garcia da
Full Text Available Estudou-se a influência do período de quiescência dos ovos no ciclo de vida de Aedes aegypti (Linnaeus, 1762 (Diptera, Culicidae em condições de laboratório, na busca de informações que possam melhorar o direcionamento das ações de controle, pois sabe-se que o ovo é a forma mais resistente do ciclo biológico, possibilitando ao mosquito ampla sobrevida, devido à resistência às adversidades climáticas. Os experimentos foram realizados numa câmara biológica, mantida à temperatura de 28 ± 1oC, com umidade relativa de 80 ± 5% e fotofase de 12 horas. Apresentam-se os dados da influência de diferentes períodos de quiescência sobre a eclosão das larvas, desenvolvimento larval e pupal, ciclo evolutivo. Verificou-se o efeito altamente significativo do período de quiescência na eclosão das larvas. O período de quiescência não influenciou nas durações dos períodos de incubação, larval e pupal. Constatou-se que ovos de um mesmo período de quiescência apresentaram períodos de incubação estatisticamente diferentes entre si. As larvas eclodiam em grupos, definidos pela incubação, e este efeito de grupo foi significativo na duração do ciclo. Pode-se afirmar que, em 99,8% dos ciclos, a variação foi determinada pela incubação.
Platonova, O V; Fedorova, M V; Lopatina, Iu V; Bezzhonova, O V; Bulgakova, T V; Platonov, A E
Host preference of the mosquitoes collected in the urban and rural habitats of Volgograd and its suburbs was studied by the precipitation reaction test. Human and avian blood was detected in Cx. pipiens, Cx. modestus, Ae. vexans, Ae. behningi, Ae. caspius, Ae. sticticus, and females of the Anopheles maculipennis. The proportion of the mosquitoes fed on birds was similar in the urban and rural biotopes whereas that of the mosquitoes feeding on humans was significantly higher in Volgograd than in its environs. The increase in the number of human blood-fed mosquitoes in the city resulted mainly from the females collected in its multi-storied buildings.
Culicidae (Insecta: Diptera em área de Floresta Atlântica, no Estado do Paraná, Brasil - DOI: 10.4025/actascibiolsci.v30i1.1411 Culicidae (Insecta: Diptera in areas of Atlantic Forest, Paraná State, Brazil - DOI: 10.4025/actascibiolsci.v30i1.1411
Mario Antonio Navarro-Silva
Full Text Available A alteração da paisagem natural pode gerar mudanças que favorecem o desenvolvimento e proliferação de determinadas espécies de Culicidae, em detrimento de outras que se deslocam para outros locais ou são extintas. Baseando-se nestas mudanças, algumas espécies podem ser utilizadas como bioindicadores do grau de degradação ambiental. O presente estudo tem como objetivo analisar a composição e riqueza de Culicidae, em dois ambientes em área de Floresta Atlântica, e avaliar se as espécies encontradas indicam o grau de preservação dos fragmentos estudados. As coletas foram realizadas em dois ambientes, denominados Carvalho e Trilha, em área de Floresta Atlântica (Mananciais da Serra, no Estado do Paraná - Brasil, nos meses de dezembro/2002 a maio/2003, utilizando-se um aspirador elétrico manual. Foram identificadas 48 espécies de 636 espécimes de Culicidae. A composição taxonômica e riqueza das espécies de Culicidae diferenciaram-se entre os ambientes estudados, provavelmente, influenciadas pelo estado de preservação dos fragmentos florestais. Os maiores valores de riqueza observados no Carvalho, assim como o predomínio das espécies da tribo Sabethini e Kerteszia sugerem reduzida ação antrópica neste fragmento florestal. De modo contrário, a composição das espécies e os menores valores de riqueza observadas na Trilha indicam grau alto de degradação ambientalModifications in the landscape can lead to the development and proliferation of some Culicidae species, in detriment of others. As a result, some species may be forced to move to other places or become locally extinct. Based on these changes, some species can be used as bioindicators of environmental degradation. The aim of this study was to assess Culicidae composition and richness in two Atlantic Forest sites (Carvalho and Trilha; State of Paraná, Brazil, and to evaluate whether they can be used as indicators of environmental degradation of these sites
Murdock, C C; Olival, Kevin J; Perkins, Susan L
We collected blood-fed, snow-melt mosquitoes (Culicidae: Culiseta and Aedes) to describe the feeding patterns of potential mosquito vectors of Jamestown Canyon virus (JCV, Bunyaviridae: Orthobunyavirus). JCV is an arthropod-borne, zoonotic virus with deer as the primary amplifying host in western alpine ecosystems. We collected mosquitoes from natural resting areas, fiber pots, and carbon-dioxide baited miniature light traps in the Colorado Rocky Mountains in 2007. We conducted two polymerase chain reactions to amplify and sequence vertebrate DNA extracted from blood-fed mosquitoes, which yielded comparable, but not identical, results. Mammal-specific primers found mule deer (Odocoileus hemionus) and elk (Cervus elaphus canadensis) as the source of all bloodmeals. To determine if unamplified bloodmeals were from nonmammalian sources, we screened all samples with conserved vertebrate primers, which confirmed the initial polymerase chain reaction results, but also found porcupine (Erethizon dorsatum) and human (Homo sapiens) as additional bloodmeal sources. We consistently found that mule deer were the primary hosts for mosquitoes in this system. These results suggest that snow-melt mosquitoes, in particular A. cataphylla, may be important vectors in western JCV alpine systems and may also act as a bridge vector for JCV from cervid virus reservoirs to humans.
Marcia Bicudo de Paula
Full Text Available OBJETIVO: Descrever a fauna Culicidae em área sob impacto da modificação ambiental causada pela construção de represa. MÉTODOS: Foi estudada a área onde estava sendo construída a Represa Porto Primavera no município de Presidente Epitácio, SP. As capturas dos culicídeos foram realizadas mensalmente, em seis pontos exploratórios antes do seu enchimento e em um ponto fixo, um ano antes (1997-1998 e outro depois do primeiro enchimento (1999-2000. Mosquitos adultos foram capturados com aspirador, no período matutino, e com armadilhas de Shannon e CDC, no período crepuscular vespertino. Os imaturos foram coletados por meio de conchadas nos criadouros maiores e com pipeta, nos menores. RESULTADOS: No período anterior ao enchimento da represa foram coletados 944 exemplares de culicídeos imaturos, distribuídos em dez gêneros. O total de adultos foi de 14.932, dos quais 7.031 mosquitos (em dez gêneros foram capturados nos pontos exploratórios e 7.901 espécimes, distribuídos em oito gêneros, no ponto fixo. Após a primeira etapa de enchimento da represa, o total de imaturos foi de 1.201 exemplares, distribuídos em quatro gêneros, e o total de mosquitos capturados foi de 5.912, distribuídos em nove gêneros. Houve redução populacional de espécies dos gêneros Aedes e Psorophora e aumento no número de espécimes dos gêneros Aedeomyia, Anopheles, Culex (Melanoconion, Mansonia e Uranotaenia. CONCLUSÕES: As mudanças ambientais decorrentes da construção da Represa Porto Primavera favoreceram o aumento da densidade de algumas populações de culicídeos vetores e que geram incômodo, com riscos potenciais de transmissão de patógenos para humanos.OBJECTIVE: To describe the culicidae fauna in an area impacted by environmental changes caused by the construction of a dam. METHODS: The studied area was the Porto Primavera dam construction site in Southeastern Brazil. Monthly culicidae samples were taken in six exploratory sites in
Full Text Available Background: Bromeliads can be epiphytic, terrestrial or saxicolous and use strategies to allow water to be retained in their leaf axils, where various arthropods can be found. These include mosquitoes, whose larvae are the most abundant and commonly found organisms in the leaf axils. The objective of this study was to look for immature forms of mosquitoes (the larval and pupal stages in bromeliads in municipal parks in São Paulo and to discuss the ecological and epidemiological importance of these insects.Methods: From October 2010 to July 2013, immature mosquitoes were collected from bromeliads in 65 municipal parks in the city of São Paulo, Brazil, using suction samplers. The immature forms were maintained until adult forms emerged, and these were then identified morphologically.Results: Two thousand forty-two immature-stage specimens belonging to the genera Aedes, Culex, Trichoprosopon, Toxorhynchites, Limatus and Wyeomyia were found in bromeliads in 15 of the 65 parks visited. Aedes albopictus was the most abundant species (660 specimens collected, followed by Culex quinquefasciatus (548 specimens and Cx. (Microculex imitator (444. The taxa with the most widespread distribution were Ae. aegypti and Toxorhynchites spp, followed by Ae. albopictus and Cx. quinquefasciatus.Conclusion: Bromeliads in urban parks are refuges for populations of native species of Culicidae and breeding sites for exotic species that are generally of epidemiological interest. Hence, administrators and surveillance and mosquito-control agencies must constantly monitor these microenvironments as the presence of these species endangers the health of park users and employees as well as people living near the parks.
Kim, Kyeong Soon; Tsuda, Yoshio; Sasaki, Toshinori; Kobayashi, Mutsuo; Hirota, Yoshikazu
We conducted laboratory experiments to verify molecular techniques of avian malaria parasite detection distinguishing between an infected mosquito (oocysts on midgut wall) and infective mosquito (sporozoites in salivary glands) in parallel with blood-meal identification from individual blood-fed mosquitoes prior to application to field survey for avian malaria. Domestic fowl infected with Plasmodium gallinaceum was exposed to a vector and non-vector mosquito species, Aedes aegypti and Culex pipiens pallens, respectively, to compare the time course of polymerase chain reaction (PCR) detection for parasite between competent and refractory mosquitoes. DNA of the domestic fowl was detectable for at least 3 days after blood feeding. The PCR-based detection of P. gallinaceum from the abdomen and thorax of A. aegypti corresponded to the microscopic observation of oocysts and sporozoites. Therefore, this PCR-based method was considered useful as one of the criteria to assess developmental stages of Plasmodium spp. in mosquito species collected in the field. We applied the same PCR-based method to 21 blood-fed C. sasai mosquitoes collected in Rinshi-no-mori Park in urban Tokyo, Japan. Of 15 blood meals of C. sasai successfully identified, 86.7% were avian-derived, 13.3% were bovine-derived. Plasmodium DNA was amplified from the abdomen of three C. sasai specimens having an avian blood meal from the Great Tit (Parus major), Pale Thrush (Turdus pallidus), and Jungle Crow (Corvus macrorhynchos). This is the first field study on host-feeding habits of C. sasai in relation to the potential role as a vector for avian malaria parasites transmitted in the Japanese wild bird community.
Ajamma, Yvonne Ukamaka; Villinger, Jandouwe; Omondi, David; Salifu, Daisy; Onchuru, Thomas Ogao; Njoroge, Laban; Muigai, Anne W. T.; Masiga, Daniel K.
The Lake Baringo and Lake Victoria regions of Kenya are associated with high seroprevalence of mosquito-transmitted arboviruses. However, molecular identification of potential mosquito vector species, including morphologically identified ones, remains scarce. To estimate the diversity, abundance, and distribution of mosquito vectors on the mainland shores and adjacent inhabited islands in these regions, we collected and morphologically identified adult and immature mosquitoes and obtained the corresponding sequence variation at cytochrome c oxidase 1 (COI) and internal transcribed spacer region 2 (ITS2) gene regions. A total of 63 species (including five subspecies) were collected from both study areas, 47 of which have previously been implicated as disease vectors. Fourteen species were found only on island sites, which are rarely included in mosquito diversity surveys. We collected more mosquitoes, yet with lower species composition, at Lake Baringo (40,229 mosquitoes, 32 species) than at Lake Victoria (22,393 mosquitoes, 54 species). Phylogenetic analysis of COI gene sequences revealed Culex perexiguus and Cx. tenagius that could not be distinguished morphologically. Most Culex species clustered into a heterogeneous clade with closely related sequences, while Culex pipiens clustered into two distinct COI and ITS2 clades. These data suggest limitations in current morphological identification keys. This is the first DNA barcode report of Kenyan mosquitoes. To improve mosquito species identification, morphological identifications should be supported by their molecular data, while diversity surveys should target both adults and immatures. The diversity of native mosquito disease vectors identified in this study impacts disease transmission risks to humans and livestock. PMID:27402888
Mogren, Christina L.; Webb, Samuel M.; Walton, William E.; Trumble, John T.
The distribution and speciation of arsenic (As) were analyzed in individuals of various life stages of a midge, Chironomus riparius, and the mosquito Culex tarsalis exposed to 1000 μg/l arsenate. X-ray absorption spectroscopy (XAS) revealed that C. riparius larvae accumulate As in their midgut, with inorganic arsenate [As(V)] being the predominant form, followed by arsenite [As(III)] and an As-thiol. Reduced concentrations of As in pupal and adult stages of C. riparius indicate excretion of As between the larval and pupal stages. In adults, As was limited to the thorax, and the predominant form was an As-thiol. In Cx. tarsalis, As was not found in high enough concentrations to determine As speciation, but the element was distributed throughout the larva. In adults, As was concentrated in the thorax and eyes of adults. These results have implications for understanding the biotransformation of As and its movement from aquatic to terrestrial environments. -- Highlights: •C. riparius larvae reduced arsenate to arsenite in the midgut. •C. riparius larvae accumulated As in the midgut, with 27% as a transformed As-thiol. •C. riparius adults retained As in the thorax, with 53% as As-thiol. •Larvae of Cx. tarsalis did not have a specific site of As accumulation. •Low concentrations of As in adults suggest reduced terrestrial transfer potential. -- Arsenic accumulation and biotransformation in aquatic insects is variable, but the location and speciation of As provides insight into the detoxification mechanisms of aquatic Diptera
[A complex of blood-sucking mosquitoes (Diptera, Culicidae) in the focus of West Nile fever in the Volgograd Region. III. Species feeding on birds and man and the rhythms of their nocturnal activity].
Lopatina, Iu V; Bezzhonova, O V; Fedorova, M V; Bulgakova, T V; Platonov, A E
The rate and nocturnal rhythm of mosquito attacks of birds and human beings were studied in the open biotopes of Volgograd and its vicinity in 2004. Thirteen and 11 species of the subfamily Culicinae were collected under the Berezantsev bell and from the traps containing a chicken (a hen), respectively; of them 9 species were common. The mosquitoes of an Anopheles maculipennis complex were caught in a small portion to the traps of both types. Most species of Aedes were highly anthropophilic, showed the minimum activity at night and their abundance considerably decreased by the early transmission period. Among the species that were active during the transmission period, Ae. vexans, Coq. richiardii, and Cx. modestus more intensively attacked a human being than birds and Cx. pipiens was frequently attracted into the hen traps. The attraction of each species of the caught varied during the transmission period. The maximum attacks of Cx. modestus and Cx. pipiens on man and birds coincide and those of Coq. Richiardii and Cx. pipiens on man was observed earlier than on birds. A possible role of mosquitoes of different species in the epizootic and epidemiological processes is discussed.
Abstract. The hematofagic effect caused by females belonging to some species of Culicidae on humans and animals can be directly related to pathogen transmission, allergic reactions and uneasiness. The emergence of populations resistant to chemical insecticides has fostered the use of alternative methods, mainly biological control. The trials were conducted in three effluent treatment lagoons, on larvae of Culicidae to test the efficiency and persistence of commercial products whose active principles are based on Bacillus thuringiensis israelensis Berliner and Bacillus sphaericus Neide. The products tested were Vectolex (a granulated formulation of B. sphaericus, Sphaericus (a liquid formulation of B. sphaericus and Bt-horus (a liquid formulation of B. thuringiensis. The products were applied biweekly and evaluations were conducted 0, 24, 48, 72, and 120 hours after each application. The lagoons were colonized by Culex nigripalpus Theobald (1.5%, Culex saltanensis Dyar (2.25%, and Culex quinquefasciatus Say (96.25%. Bt-horus reduced larvae by 89.06%, 83.97% and 89.96% at 24, 48 and 72 hours after product application, respectively. The granulated and the liquid formulations containing B. sphaericus reduced larvae by 98.89 % and 98.34% 24 hours after application, and by 99.79% and 99.78% after 48 hours, respectively. The products and the different formulations were effective in controlling larvae of all three Culicidae species in lagoons with high levels of organic matter, but the persistence was recorded in two and three days for products containing respectively B. sphaericus and B. thuringiensis israelensis.
Characterization of Aedes albopictus (Skuse, 1894 (Diptera:Culicidae larval habitats near the Amazon River in Colombia Caracterización preliminar de los sitios de cría de Aedes (Stegomyia albopictus (Skuse, 1894 (Diptera: Culicidae en el municipio de Leticia, Amazonas, Colombia
Víctor Alberto Olano
Full Text Available Introduction. Because the role of Aedes albopictus as an incriminated vector of several viral pathogens, its control is important to human health. To establish appropriate control methods, characterization of the larval habitats is a necessary first step.
Objective. Habitats of the immature stages of Ae. albopictus were characterized with respect to physical-chemical parameters and by floral and faunal arrays present.
Materials and methods. Leticia is located at the southernmost tip of Colombia on the banks of the Amazon River. In the urban area, 154 houses were inspected in December 2002 and January 2003. Physical-chemical data were collected, including exposure to sunlight, location, container size and material, water conductivity, and dissolved oxygen. Macroinvertebrates and plankton samples were taken at each positive larval site. The results were compared using descriptive analysis, principal component analysis, classification dendrograms, and diversity indexes.
Results. Twenty-one habitats were found positive for Diptera, and 13 were positive for Ae. albopictus larvae. Most of the positive habitats (92% were located near the houses--they were small or medium size receptacles located in the shade. This water generally had low conductivity and low turbidity, although high values of these parameters were also identified. The habitats had low diversity indexes for macroinvertebrates and high diversity indexes for plankton. In the principal component analysis, significant correlation was found with mites, oligochaetes and hemipterans (the macroinvertebrates and with bacilarophyceaes, clorophyceaes and cianophyceas (the algal forms.
Conclusion. In Leticia, females of Ae. albopictus were found in newly established habitats with sufficient availability of resources, low conductivity, and turbidity, lower intra-and interspecific competition.Introducción. Dada la importancia de Aedes albopictus en la salud pública, es necesario
Maria da Graça Teixeira Portes
Full Text Available INTRODUÇÃO: No Brasil, a Região Amazônica é endêmica em malária. Em Santa Catarina, a malária foi eliminada na década de 80. A partir daí, ocorreram poucos casos autóctones isolados, e esporádicos. No entanto, em função da existência do vetor em seu território, da existência de extensa área endêmica no Brasil e da grande mobilidade de pessoas em áreas turísticas no estado, existe a probabilidade de reintrodução da doença. MÉTODOS: Utilizou-se os seguintes dados: Banco de Dados do Núcleo de Entomologia da Fundação Nacional de Saúde, Santa Catarina (ACCES,1997-2000; Sistema de Informação de Vigilância Epidemiológica, Secretaria de Vigilância em Saúde (Malária/SC e Sistema de Informação de Notificação e Agravo(SINAN/SC. Os mesmos foram transportados e analisados, no programa Microsoft Office Excel 2007. RESULTADOS: As coletas foram realizadas em 48 municípios, 159 localidades, sendo identificados 12.310 Culicídeos, 11.546 (93,7% Anopheles e 764 (6,2% como outros. Foram identificados três subgêneros e 13 espécies de anofelinos. CONCLUSÕES: Considerando que nos municípios pesquisados, foi identificada a presença de importantes vetores como Anopheles cruzii e Anopheles albitasis e há circulação de pessoas infectadas provenientes de áreas endêmicas, pode-se considerar que os mesmos são áreas receptivas e vulneráveis à malária. Essas espécies são suspeitas de serem responsáveis pela transmissão de malária na região, principalmente nos municípios de Gaspar, Indaial e Rodeio.INTRODUCTION: The Amazon region of Brazil is endemic for malaria. In the State of Santa Catarina, malaria was eliminated in the 1980s. Since then, a few sporadic isolated autochthonous cases have occurred. However, because malaria vectors are present within Brazilian territory and extensive endemic areas exist in this country, along with the great mobility of people in tourist areas of Santa Catarina, there is the likelihood of reintroduction of the disease. METHODS: The following data were used: the database of the Entomology Group of the National Health Foundation, Santa Catarina (ACCES, 1997-2000; the epidemiological surveillance information system of the Health Surveillance Department (Malaria/SC; and the notifiable disease information system (SINAN/SC. These data were transferred to and analyzed in the Microsoft Office Excel 2007 software. RESULTS: Collections were carried out in 48 municipalities and 159 localities, and 12,310 culicids, 11,546 anophelines (93.7% and 764 others (6.2% were identified. Three subgenera and 13 species of anophelines were identified. CONCLUSIONS: Given that in the municipalities investigated, important vectors such as Anopheles cruzii and Anopheles albitasis were found to be present, with movements of infected individuals from endemic areas, these areas can be considered to be receptive and vulnerable to malaria. These species are suspected of being responsible for malaria transmission in this region, especially in the municipalities of Gaspar, Indaial and Rodeio.
Preferência por local de oviposição de Aedes albopictus (Skuse (Diptera, Culicidae, em relação à presença de imaturos da própria espécie, sob condições de laboratório Aedes (Stegomyia albopictus (Skuse (Diptera, Culicidae, preference for oviposition site related with homospecific immatures presence, under laboratory conditions
Andreia Aparecida Barbosa
Full Text Available Aedes (Stegomyia albopictus (Skuse, 1894 is an exotic Culicidae species in Brazil. Since its first report in this country, the mosquito has been increasing its geographic distribution. This mosquito is a natural dengue and Japanese Encephalitis virus vector in Asia. The females preference for oviposition sites related with homospecific immature presence was assessed. The experiment was performed with Aedes albopictus from laboratory colony since March ]999, in the Laboratório de Entomologia Médica e Veterinária, Departamento de Zoologia, Universidade Federal do Paraná. The preferred container was the one that kept pupae for 24 hours, with 643 eggs, 30,6% at total. The eggs recipients received 11,45% from total set by the females, and the following numbers to the others: larva 1 (15,79%, larva 2 (14,69%, pupa 1 (20,74%, pupa 2 (30,58%, control (6,75%. Although the ANOVA did not detect significant difference among the treatments, the data possibly indicate that Aedes albopictus prefer laying eggs in containers previously colonized by immature.
Preferência por hospedeiro e estratificação de Culicidae (Diptera em área de remanescente florestal do Parque Regional do Iguaçu, Curitiba, Paraná, Brasil Host preference and Culicidae stratification in area of degradated inside forest of Regional do Iguaçu Park, Curitiba, Paraná, Brazil
Ana Cristina Tissot
Full Text Available A investigação das populações de Culicidae em áreas de remanescentes florestais inseridas em área urbana, podem fornecer subsídios para compreensão dos processos de utilização de habitats apresentando diferentes graus de interferência antrópica. Foram investigadas espécies potencialmente zoofílicas durante o período vespertino no interior de remanescente florestal, no espaço urbano de Curitiba, Paraná. Durante o período de setembro de 2000 a junho de 2001, foram realizadas cinco coletas por estação, com auxílio de armadilhas CDC-M instaladas em dois estratos verticais, a 1,5 m do solo e na copa das árvores (6 m. Como iscas foram utilizados mamíferos Cavia porcellus (Linnaeus, 1758 (Rodentia, Cavidae e aves Nothura maculosa (Temminck, 1815 (Tinamiformes, Tinamidae em cada um dos estratos, com revezamento das iscas animais. As armadilhas foram operadas no intervalo horário das 16:00 às 20:00 h, sendo retiradas amostras a cada intervalo de 30 minutos. Em 60 horas de operação das armadilhas CDC-M, foram capturados 1.407 exemplares de Culicidae, sendo 1.143 espécies identificadas, distribuídas em nove gêneros e 13 espécies. As espécies mais freqüentes foram Mansonia(Mansonia fonsecai (Pinto, 1932 e Mansonia (Mansonia pessoai (Barreto e Coutinho, 1944, destaca-se também a ocorrência de: Ochlerotatus (Ochlerotatus scapularis (Rondani, 1848; Psorophora (Janthinosoma ferox (Humboldt, 1819 e Aedes (Stegomyia albopictus (Skuse, 1894. Na área foram detectadas a presença de espécies com graus variados de importância epidemiológica e com tendência a explorar ambientes exófilos, florestais e peridomiciliares.Parks and plazas (green areas or vegetation islands within urban areas can provide conditions for the development of populations of mosquitoes, many species of which are very adaptable to a variety of environments. The species of mosquitoes in the family Culicidae with animal hosts, in a vegetation island within an
Evaluation préliminaire de l'activité larvicide des extraits aqueux des feuilles du ricin (Ricinus communis L. et du bois de thuya (Tetraclinis articulata (Vahl Mast. sur les larves de quatre moustiques culicidés : Culex pipiens (Linné, Aedes caspius (Pallas, Culiseta longiareolata (Aitken et Anopheles maculipennis (Meigen
Full Text Available Preliminary evaluation of larvicidal activity of aqueous extracts from leaves of Ricinus communis L. and from wood of Tetraclinis articulata (Vahl Mast. on the larvae of four mosquito species: Culex pipiens (Linné, Aedes caspius (Pallas, Culiseta longiareolata (Aitken and Anopheles maculipennis (Meigen. Aqueous extracts of Ricinus communis leaves and Tetraclinis articulata wood showed strong toxic activity against larvae of several mosquitoes. In this study, insecticide effects of these plant extracts have been investigated on 2nd and 4th instars larvae of Culicidae insects, Culex pipiens (Linné, Aedes caspius (Pallas, Culiseta longiareolata (Aitken and Anopheles maculipennis (Meigen. After 24 hours of exposition, bioassays revealed low lethal concentrations LC50. To control mosquitoes, these plant extracts might be used as natural biocides.
Toral y Caro, Muriel
Les moustiques sont responsables de nuisances directes et indirectes, chez l'homme et chez l'animal. C'est pourquoi il est intéressant de tester l'efficacité de nouvelles molécules sur ces insectes. Ce travail expérimental vise à tester l'efficacité potentielle du fipronil sur les moustiques appartenant au complexe Culex pipiens au moyen d'un nouveau test mis en place au laboratoire. Une première partie de ce travail est consacrée à l'étude bibliographique des caractéristiques de Culex ...
Jan 31, 2012 ... This study was conducted to develop sequential sampling plans to estimate larval density of Liriomyza sativae Blanchard (Diptera: Agromyzidae) at three precision levels in cucumber greenhouse. The within- greenhouse spatial patterns of larvae were aggregated. The slopes and intercepts of both Iwao's.
Mar 19, 2014 ... Wiedemann (Diptera: Tephritidae). Flávia Queiroz de Oliveira1*, José Bruno Malaquias2, Wennia Rafaelly de Souza Figueiredo3,. Jacinto de Luna Batista4, Eduardo Barbosa Beserra1 and Robério de Oliveira4. 1Universidade Estadual da Paraíba (UEPB), campus I/Campina Grande, Bodocongó, Paraíba, ...
Bkhache, Meriem; Tmimi, Fatim-Zohra; Charafeddine, Omar; Faraj, Chafika; Failloux, Anna-Bella; Sarih, M'hammed
Mosquitoes of the Culex pipiens complex, competent vectors for West Nile virus (WNV) and Rift Valley fever virus (RVFV) are widely targeted by insecticide treatments. The intensive application of chemical insecticides led to the development of resistance in many insects including Culex pipiens mosquitoes. The absence of data on resistance mechanisms in Morocco allow us to assess the levels of lambda-cyhalothrin resistance and the frequency of the mutated gene L1014F kdr in different forms of Cx. pipiens complex from three regions of Morocco. Mosquito adults were reared from immature stages collected in three different regions in Morocco (Tangier, Casablanca and Marrakech). Standard WHO insecticide susceptibility tests were conducted on adults emerged from collected larvae. Specimens were identified as belonging to the Culex pipiens complex using a multiplex PCR assay with diagnostic primers designed from the flanking region of microsatellite CQ11. Identified mosquitoes were then tested for the presence of the L1014F kdr mutation using PCR assay. Our results showed that 21% of the tested population has a resistance to lambda-cyhalothrin. The molecular identification of survivors shows that 43% belonged to the Cx. pipiens pipiens and only 9.5% to the Cx. pipiens molestus form. On the other hand, 416 specimens were screened for the L1014F kdr mutation. L1014F mutation was detected in different forms of Cx. pipiens in different sites. The frequency of L1014F mutation was similar between the Cx. pipiens pipiens form and hybrid form, while it was lower in the Cx. pipiens molestus form. The presence of the L1014F kdr allele was significantly associated with resistance to lambda-cyhalothrin in Cx. pipiens pipiens (P Morocco. These findings will provide important information to propose more adapted vector control measures towards this mosquito species, potential vector of arboviruses.
Control Assoc 21: 182 – 186 . 7. Servicio de Erradicación de la Malaria (SEM) , 1957 . Plan de erradi- cación de la malaria en Colombia...cat populations ( Felis catus ) in Spain, Italy, Argentina at micro - geographical level. Acta Theriol (Warsz) 43: 39 – 66 . 33. Ruiz-García M...Kimmel M , Chakravorty R , King JP , Bamshad M , Watkins WS , Jorde LB , 1998 . Signatures of population expansion in micro
Chelsea T. Smartt
Full Text Available We report a laboratory colony of Culex quinquefasciatus mosquitoes were experimentally able to salivate Zika virus (ZIKV, Flaviviridae; Flavivirus at 16 days post infection (dpi. ZIKV RNA was detected in bodies and in saliva deposited on filter paper cards with subsequent studies demonstrating the presence of live ZIKV in saliva.
Full Text Available Background: Anopheles stephensi is a sub-tropical species and has been considered as one of the most important vector of human malaria throughout the Middle East and South Asian region including the malarious areas of southern Iran. Current reports confirmed An. stephensi resistance to temephos in Oman and India. However, there is no comprehensive research on mechanisms of temephos resistance in An. stephensi in the literature. This study was designed in order to clarify the enzymatic and molecular mechanisms of temephos resistance in this species.Methods: Profile activities of α- and ß-esterases, mixed function oxidase (MFO, glutathione-S-transferase (GST, insensitive acetylcholinesterase, and para-nitrophenyl acetate (PNPA-esterase enzymes were tested for An. stephensi strain with resistance ratio of 15.82 to temephos in comparison with susceptible strain.Results: Results showed that the mean activity of α-EST, GST and AChE enzymes were classified as altered indicating metabolic mechanisms have considerable role in resistance of An. stephensi to temephos. Molecular study using PCR-RFLP method to trace the G119S mutation in ACE-1 gene showed lack of the mutation responsible for organophosphate insecticide resistance in the temephos-selected strain of An. stephensi.Conclusion: This study showed that the altered enzymes but not targets site insensitivity of ACE-1 are responsible for temephos resistance in An. stephensi in south of Iran.
de Oliveira, Caroline Dantas; Tadei, Wanderli Pedro; Abdalla, Fábio Camargo; Paolucci Pimenta, Paulo Filemon; Marinotti, Osvaldo
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.
of adult mosquitoes, with humans acting as baits, was employed for the study. Environmental inspection and collection of larvae in the water-holding containers around the buildings were used to study the breeding sites of the mosquitoes. A total of 73 adult mosquitoes, made up of Aedes albopictus (76.71%) and A. aegypti ...
Tantely, Michaël Luciano; Le Goff, Gilbert; Boyer, Sébastien; Fontenille, Didier
An updated checklist of 235 mosquito species from Madagascar is presented. The number of species has increased considerably compared to previous checklists, particularly the last published in 2003 (178 species). This annotated checklist provides concise information on endemism, taxonomic position, developmental stages, larval habitats, distribution, behavior, and vector-borne diseases potentially transmitted. The 235 species belong to 14 genera: Aedeomyia (3 species), Aedes (35 species), Anopheles (26 species), Coquillettidia (3 species), Culex (at least 50 species), Eretmapodites (4 species), Ficalbia (2 species), Hodgesia (at least one species), Lutzia (one species), Mansonia (2 species), Mimomyia (22 species), Orthopodomyia (8 species), Toxorhynchites (6 species), and Uranotaenia (73 species). Due to non-deciphered species complexes, several species remain undescribed. The main remarkable characteristic of Malagasy mosquito fauna is the high biodiversity with 138 endemic species (59%). Presence and abundance of species, and their association, in a given location could be a bio-indicator of environmental particularities such as urban, rural, forested, deforested, and mountainous habitats. Finally, taking into account that Malagasy culicidian fauna includes 64 species (27%) with a known medical or veterinary interest in the world, knowledge of their biology and host preference summarized in this paper improves understanding of their involvement in pathogen transmission in Madagascar. PMID:27101839
N. L. Cerqueira
Full Text Available Em quinze gêneros, cento e vinte e seis espécies de mosquitos foram constatadas no material capturado pelo Servicio de Fiebre Amarilla desde 1933 até 1942. Êste número, três vezes mais elevado do que o existente na literatura para o país, seria ainda maior se possível fôsse identificar sem o auxílio de machos inúmeras fêmeas das espécies de Culex. Tôdas as espécies estudadas apresentavam suas distribuições geográficas nos departamentos e províncias onde casos de Febre Amarela foram observados. Algumas cosiderações foram feitas em torno de espécies que não correspondiam exatamente com as descrições existentes, assim como descrições de outras foram dadas, cujos sexos opostos apenas eram conhecidos.One hundred and twenty-six species of mosquitoes, corresponding fifteen genera, have been found in material collected by the Bolivian Yellow Fever Service between 1933 and 1942. This number is three times that given for the country in existing literature and would be even largar if it were possible to identify a consierable group of Culex mosquitoes composed principally of female specimens. All species studied come from Departmetns and Provinces where cases of yellow fever have been found. Consideration has been given to certain species which do not agree exactly with existing descriptions, and supplementary descriptions have been made for the male or female of two additional species for which only description of the opposite sex had existed.
Kalan, Katja; Šušnjar, Jana; Ivović, Vladimir; Buzan, Elena
The first record of Aedes koreicus was made in the village of Lovrenc na Dravskem Polju, north-eastern part of the country. The discovery of Ae. koreicus in various continental European countries motivated us to revise samples of the collected Aedes japonicus japonicus. We found Ae. koreicus in samples from 2013, where the larvae were misidentified as Ae. j. japonicus. The species was identified morphologically and molecularly. The first discovery of Ae. koreicus advocates an urgent need for a nationwide mosquito surveillance programme.
halifaxii. In Palawan and Balabac, Philippine Islands, immatures were found in densely shaded coconut husks and in large metal lined boxes in association...areas impacted by human activities the breeding places were sunny grassy fields with some algae, ruts and puddles in roads, coconut shells in the...shade, top of oil drums in the shade, and in large packing containers. Additionally, immatures were taken from a large metal-lined box, a sunlit truck
Lacour, Guillaume; Chanaud, Lionel; L'Ambert, Grégory; Hance, Thierry
In temperate areas, population dynamics of the invasive Asian tiger mosquito Aedes albopictus are strongly affected by winter. The work we present here analyzes the adaptive synchronization of the diapause process in the wintry generation of A. albopictus, where the egg stage is exposed to adverse winter conditions. The seasonal pattern of egg laying activity of a French Mediterranean population of the Asian tiger mosquito was monitored weekly for 2 years with ovitraps. The field diapause incidence and the critical photoperiod (CPP, i.e. the maternal day length inducing diapause in 50% of the eggs), were determined by hatching experiments on the collected eggs. The period of diapause termination was estimated by a field survey of the first hatchings for both years. The CPP is equal to 13.5 hours of light and occurs in the field on the 25th of August. Thus, it is on September 11th, 17 days after the CPP, that 50% of the eggs are in a prediapause stage in the field. The egg diapause rate increases rapidly during September, whereas the mean number of eggs laid decreases sharply after mid-September. Surprisingly, after having reached a peak of 95% at the end of September, from mid-October the diapause incidence declined and stayed below 50%. Indeed, both years the diapause initiates before the rapid decrease of the environmental temperature. This leaves a sufficient period of time to the complete development of one generation of A. albopictus with effective induction of diapause in the laid eggs. The very first larvae hatched were sampled both years in the first half of March. With 20 to 26 weeks in the egg stage and about 7 weeks in the larval stages, the first annual generation spends a long time in immature stages. On a practical point of view, this long development time represents a wide window for eggs and larvae control in early spring.
Full Text Available Body size is a physical factor of crucial importance underlying important traits of the reproductive dynamics of both sexes in mosquitoes. Most studies on the influence of body size in mating success of dengue vectors addressed sperm transfer to females and did not consider egg production, a prerequisite for population maintenance; male body size impact on reproduction has attracted little research interest with respect to sterile insect technique. In experiments involving differently sized adults, we examined whether the body size of the mates is a source of variation in reproductive outcome in Aedes aegypti. In the absence of male partners, large females (LF showed better fecundity than small females (SF. In intraclass mating trials, egg production was much greater in largesized than smallsized pairs. There were comparable fecundities in large females mated with small males and large pairs. [SF•SM] and [SF•LM] pairs showed equivalent fecundity. Nonmating did not result in the production of viable eggs by either small or large females. We also observed that eggs produced by largesized females mated with small males had better hatching success than those from either small or large pairs. Mating between small females and large males resulted in poor egg viability.
Tantely Michaël Luciano
Full Text Available An updated checklist of 235 mosquito species from Madagascar is presented. The number of species has increased considerably compared to previous checklists, particularly the last published in 2003 (178 species. This annotated checklist provides concise information on endemism, taxonomic position, developmental stages, larval habitats, distribution, behavior, and vector-borne diseases potentially transmitted. The 235 species belong to 14 genera: Aedeomyia (3 species, Aedes (35 species, Anopheles (26 species, Coquillettidia (3 species, Culex (at least 50 species, Eretmapodites (4 species, Ficalbia (2 species, Hodgesia (at least one species, Lutzia (one species, Mansonia (2 species, Mimomyia (22 species, Orthopodomyia (8 species, Toxorhynchites (6 species, and Uranotaenia (73 species. Due to non-deciphered species complexes, several species remain undescribed. The main remarkable characteristic of Malagasy mosquito fauna is the high biodiversity with 138 endemic species (59%. Presence and abundance of species, and their association, in a given location could be a bio-indicator of environmental particularities such as urban, rural, forested, deforested, and mountainous habitats. Finally, taking into account that Malagasy culicidian fauna includes 64 species (27% with a known medical or veterinary interest in the world, knowledge of their biology and host preference summarized in this paper improves understanding of their involvement in pathogen transmission in Madagascar.
Full Text Available Although they are important disease vectors mosquito biodiversity in Pakistan is poorly known. Recent epidemics of dengue fever have revealed the need for more detailed understanding of the diversity and distributions of mosquito species in this region. DNA barcoding improves the accuracy of mosquito inventories because morphological differences between many species are subtle, leading to misidentifications.Sequence variation in the barcode region of the mitochondrial COI gene was used to identify mosquito species, reveal genetic diversity, and map the distribution of the dengue-vector species in Pakistan. Analysis of 1684 mosquitoes from 491 sites in Punjab and Khyber Pakhtunkhwa during 2010-2013 revealed 32 species with the assemblage dominated by Culex quinquefasciatus (61% of the collection. The genus Aedes (Stegomyia comprised 15% of the specimens, and was represented by six taxa with the two dengue vector species, Ae. albopictus and Ae. aegypti, dominant and broadly distributed. Anopheles made up another 6% of the catch with An. subpictus dominating. Barcode sequence divergence in conspecific specimens ranged from 0-2.4%, while congeneric species showed from 2.3-17.8% divergence. A global haplotype analysis of disease-vectors showed the presence of multiple haplotypes, although a single haplotype of each dengue-vector species was dominant in most countries. Geographic distribution of Ae. aegypti and Ae. albopictus showed the later species was dominant and found in both rural and urban environments.As the first DNA-based analysis of mosquitoes in Pakistan, this study has begun the construction of a barcode reference library for the mosquitoes of this region. Levels of genetic diversity varied among species. Because of its capacity to differentiate species, even those with subtle morphological differences, DNA barcoding aids accurate tracking of vector populations.
Irma Fátima Agrela Da Silva
Full Text Available Mosquitoes are responsible for the transmission of various diseases that affect the health of the Venezuelan population. The increase in the incidence of malaria and the emergence of diseases such as chikungunya and Zika make it necessary to implement control measures to reduce the impact of these diseases in Venezuela. To do this, it is essential to know the aspects related to their morphology, bioecology and the characteristics that make possible the participation of mosquitoes in the transmission of these diseases. The purpose of this review is to describe these aspects.
Osta Mike A
Full Text Available Abstract Background Analysis of Culex pipiens mosquitoes collected from a single site in Lebanon in 2005, revealed an alarming frequency of ace-1 alleles conferring resistance to organophosphate insecticides. Following this, in 2006 the majority of municipalities switched to pyrethroids after a long history of organophosphate usage in the country; however, since then no studies have assessed the impact of changing insecticide class on the frequency of resistant ace-1 alleles in C. pipiens. Methods C. pipiens mosquitoes were captured indoors from 25 villages across the country and subjected to established methods for the analysis of gene amplification at the Ester locus and target site mutations in ace-1 gene that confer resistance to organophosphates. Results We conducted the first large-scale screen for resistance to organosphosphates in C. pipiens mosquitoes collected from Lebanon. The frequency of carboxylesterase (Ester and ace-1 alleles conferring resistance to organophosphates were assessed among C. pipiens mosquitoes collected from 25 different villages across the country between December 2008 and December 2009. Established enzymatic assay and PCR-based molecular tests, both diagnostic of the major target site mutations in ace-1 revealed the absence of the F290V mutation among sampled mosquitoes and significant reduction in the frequency of G119S mutation compared to that previously reported for mosquitoes collected from Beirut in 2005. We also identified a new duplicated ace-1 allele, named ace-1D13, exhibiting a resistant phenotype by associating a susceptible and a resistant copy of ace-1 in a mosquito line sampled from Beirut in 2005. Fisher’s exact test on ace-1 frequencies in the new sample sites, showed that some populations exhibited a significant excess of heterozygotes, suggesting that the duplicated allele is still present. Starch gel electrophoresis indicated that resistance at the Ester locus was mainly attributed to the
Faulde, Michael K; Ahmed, Ammar A
The Horn of Africa represents a region formerly known to be highly susceptible to mosquito-borne infectious diseases. In order to monitor and analyze the current presence and threat of vector mosquitoes, continuous and standardized trapping using CDC light traps without an additional CO2-generator has been carried out at six selected monitoring sites located in Djibouti City, from August 2008 until December 2009. An overall of 620 haematophageous Diptera were trapped, 603 (97.3%) were mosquitoes, 10 (1.6%) were sand flies, and 7 (1.1%) were biting midges, respectively. Genus distribution of mosquitoes revealed that 600 (99.5%) were Culex spp., 2 (0.3%) were Anopheles sergentii, and 1 (0.2%) was Aedes aegypti. Culex species were represented by Cx. quinquefasciatus (78.5%), and Cx. pipiens ssp. torridus (21.5%). The later species was first detected focally in early December 2009 showing a strongly increasing population density resulting in a maximum trap rate of 25 mosquitoes per trap night. Sand flies were all Sergentomyia antennata, and biting midges of the genus Culicoides were represented by C. nubeculosus (71.4%) and C. vexans (28.6 %). The findings included the first records for Cx. pipiens ssp. torridus and An. sergentii in Djibouti. However, none of the captured female Culex spp, the known vector for West Nile Virus, showed positive results for viral nucleic acids using WNV RT-real time PCR system. Also, females An. sergentii were Plasmodium falciparum and P. vivax circumsporozoite protein negative.
Zittra, Carina; Flechl, Eva; Kothmayer, Michael; Vitecek, Simon; Rossiter, Heidemarie; Zechmeister, Thomas; Fuehrer, Hans-Peter
Culex pipiens complex taxa differ in behaviour, ecophysiology and epidemiologic importance. Despite their epidemiologic significance, information on genetic diversity, occurrence and seasonal and spatial distribution patterns of the Cx. pipiens complex is still insufficient. Assessment of seasonal and spatial distribution patterns of Culex pipiens forms and their congener Cx. torrentium is crucial for the understanding of their vector-pathogen dynamics. Female mosquitoes were trapped from April-October 2014 twice a month for a 24-h time period with BG-sentinel traps at 24 sampling sites in eastern Austria, using carbon dioxide as attractant. Ecological forms of Cx. pipiens s.l. and their hybrids were differentiated using the CQ11 locus, and Cx. pipiens forms and their congener Cx. torrentium using the ACE-2 gene. Differential exploitation of ecological niches by Cx. pipiens forms and Cx. torrentium was analysed using likelihood ratio tests. Possible effects of environmental parameters on these taxa were tested using PERMANOVA based on distance matrices and, if significant, were modelled in nMDS ordination space to estimate non-linear relationships. For this study, 1476 Culex spp. were sampled. Culex pipiens f. pipiens representing 87.33 % of the total catch was most abundant, followed by hybrids of both forms (5.62 %), Cx. torrentium (3.79 %) and Cx. pipiens f. molestus (3.25 %). Differences in proportional abundances were found between land cover classes. Ecological parameters affecting seasonal and spatial distribution of these taxa in eastern Austria are precipitation duration, air temperature, sunlight and the interaction term of precipitation amount and the Danube water level, which can be interpreted as a proxy for breeding habitat availability. The Cx. pipiens complex of eastern Austria comprises both ecologically different forms, the mainly ornithophilic form pipiens and the mainly mammalophilic and anthropophilic form molestus. Heterogeneous agricultural
Boccolini, Daniela; Toma, Luciano; Di Luca, Marco; Severini, Francesco; Romi, R; Remoli, Maria Elena; Sabbatucci, Michela; Venturi, Giulietta; Rezza, Giovanni; Fortuna, Claudia
We investigated the susceptibility of an Italian population of Culex pipiens mosquitoes to Zika virus (ZIKV) infection, tested in parallel with Aedes aegypti, as a positive control. We analysed mosquitoes at 0, 3, 7, 10, 14, 20 and 24 days after an infectious blood meal. Viral RNA was detected in the body of Cx. pipiens up to three days post-infection, but not at later time points. Our results indicate that Cx. pipiens is not susceptible to ZIKV infection. This article is copyright of The Authors, 2016.
Čabanová, V.; Miterpáková, M.; Valentová, D.; Blažejová, Hana; Rudolf, Ivo; Stloukal, E.; Hurníková, Z.; Dzidová, M.
Roč. 11, č. 1 (2018), č. článku 261. ISSN 1756-3305 Institutional support: RVO:68081766 Keywords : Culex pipiens complex * West Nile virus * Diptera Culicidae * Anopheles hyrcanus * Dirofilaria immitis * Aedes albopictus * endemic area * 1st record * Slovakia * vector * Dirofilaria * mosquito-borne diseases * Anopheles maculipennis complex * xenomonitoring Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology Impact factor: 3.080, year: 2016
Mosquito-borne illnesses are of great concern throughout the world, and chemical insecticides are commonly employed to decrease mosquito populations. However, the developmental insecticide pipeline for vector control has primarily been filled by repurposed agricultural products, and is hampered by t...
Estirpes de Bacillus thuringiensis efetivas contra insetos das ordens Lepidoptera, Coleoptera e Diptera Bacillus thuringiensis strains effective against insects of Lepidoptera, Coleoptera and Diptera orders
Lílian Botelho Praça
Full Text Available O objetivo deste trabalho foi selecionar entre 300 estirpes de Bacillus thuringiensis as efetivas simultaneamente contra larvas de Spodoptera frugiperda J.E. Smith e Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae, Anthonomus grandis Boheman (Coleoptera: Curculionidae, Aedes aegypti Linnaeus e Culex quinquefasciatus Say (Diptera: Culicidae. Foram selecionadas duas estirpes de B. thuringiensis, denominadas S234 e S997, que apresentaram atividade contra as três ordens de insetos. As estirpes foram caracterizadas por métodos morfológicos, bioquímicos e moleculares. As mesmas apresentaram duas proteínas principais de 130 e 65 kDa, produtos de reação em cadeia da polimerase de tamanho esperado para a detecção dos genes cry1Aa, cry1Ab, cry1Ac, cry1B e cry2 e cristais bipiramidais, cubóides e esféricos.The aim of this work was to select among 300 strains of Bacillus thuringiensis those which are simultaneously effective against larvae of Spodoptera frugiperda J.E. Smith and Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae, Anthonomus grandis Boheman (Coleoptera: Curculionidae, Aedes aegypti Linnaeus and Culex quinquefasciatus Say (Diptera: Culicidae. Two strains of B. thuringiensis were selected, S234 and S997, which presented activity against those three insect orders. Both strains were characterized by morphological, biochemical and molecular methods. They have presented two main proteins with 130 and 65 kDa, polimerase chain reaction products with expected sizes for detection of the genes cry1Aa, cry1Ab, cry1Ac, cry1B and cry2 and bipiramidal, cubical and spherical crystals.
Malek Besbes Hlila
Full Text Available Objective: To determine the larvicidal activity of sixteen extracts of Scabiosa arenaria Forssk. (S. arenaria against the third instar larvae of Culex pipiens L. (C. pipiens. Methods: Larvicidal activity of S. arenaria extracts was determined according to World Health Organization. Twenty third instars of the C. pipiens were exposed to different concentrations (15 µg/mL to 60 µg/mL of extracts. Mortality was recorded after 24 h of exposure. Results: The roots ethyl acetate fraction of S. arenaria had a significant toxic effect on larvae of C. pipiens, with high mortality percentage (100.0% ± 2.2% at 60 µg/mL, and 50% lethal concentration value of LC50 = (15.00 ± 0.09 µg/mL. Conclusions: Results show that roots ethyl acetate could be used for the production of natural bio-pesticides which could decrease our dependence on chemical pesticides.
Amara Korba, Raouf; Alayat, Moufida Saoucen; Bouiba, Lazhari; Boudrissa, Abdelkarim; Bouslama, Zihad; Boukraa, Slimane; Francis, Frederic; Failloux, Anna-Bella; Boubidi, Saïd Chaouki
We investigated the ecological differentiation of two members of the Culex pipiens complex, Cx. p. pipiens form pipiens and Cx. p. pipiens form molestus in three sites, El-Kala, M'Sila and Tinerkouk in Algeria. These two forms are the most widespread mosquito vectors in temperate regions exhibiting important behavioural and physiological differences. Nevertheless, this group of potential vectors has been poorly studied, particularly in North Africa. Ten larval populations of Cx. p. pipiens were sampled from various above- and underground habitats in three zones representing the three bioclimatic regions in Algeria. The reproduction characteristics were also investigated in the laboratory to define the rates of autogeny and stenogamy. Identification of Cx. p. pipiens members present in Algeria was achieved using a molecular analysis with the microsatellite CQ11 locus. We detected larvae of Cx. p. pipiens in all areas suggesting that the species is a ubiquitous mosquito well adapted to various environments. To our knowledge, this study provides the first molecular evidence of the presence of the Cx. p. pipiens form molestus and hybrids (molestus/pipiens) in Algeria with a high proportion of molestus form (48.3 %) in comparison with hybrids (36.8 %) and pipiens form (14.9 %). Some unexpected correlations between the proportion of forms pipiens, molestus and hybrids, and mosquito biological characteristics were observed suggesting some epigenetic effects controlling Cx. p. pipiens mating and reproduction. Consequences for pathogen transmission are discussed.
Mélissanne de Wispelaere
Full Text Available Japanese encephalitis virus (JEV is the causative agent of Japanese encephalitis, the leading cause of viral encephalitis in Asia. JEV transmission cycle involves mosquitoes and vertebrate hosts. The detection of JEV RNA in a pool of Culex pipiens caught in 2010 in Italy raised the concern of a putative emergence of the virus in Europe. We aimed to study the vector competence of European mosquito populations, such as Cx. pipiens and Aedes albopictus for JEV genotypes 3 and 5.After oral feeding on an infectious blood meal, mosquitoes were dissected at various times post-virus exposure. We found that the peak for JEV infection and transmission was between 11 and 13 days post-virus exposure. We observed a faster dissemination of both JEV genotypes in Ae. albopictus mosquitoes, when compared with Cx. pipiens mosquitoes. We also dissected salivary glands and collected saliva from infected mosquitoes and showed that Ae. albopictus mosquitoes transmitted JEV earlier than Cx. pipiens. The virus collected from Ae. albopictus and Cx. pipiens saliva was competent at causing pathogenesis in a mouse model for JEV infection. Using this model, we found that mosquito saliva or salivary glands did not enhance the severity of the disease.In this study, we demonstrated that European populations of Ae. albopictus and Cx. pipiens were efficient vectors for JEV transmission. Susceptible vertebrate species that develop high viremia are an obligatory part of the JEV transmission cycle. This study highlights the need to investigate the susceptibility of potential JEV reservoir hosts in Europe, notably amongst swine populations and local water birds.
Full Text Available West Nile virus (WNV and Rift Valley fever virus (RVFV are two emerging arboviruses transmitted by Culex pipiens species that includes two biotypes: pipiens and molestus. In Lebanon, human cases caused by WNV and RVFV have never been reported. However, the introduction of these viruses in the country is likely to occur through the migratory birds and animal trades. In this study, we evaluated the ability of Cx. pipiens, a predominant mosquito species in urban and rural regions in Lebanon, to transmit WNV and RVFV. Culex egg rafts were collected in the West Bekaa district, east of Lebanon and adult females of Cx. pipiens were experimentally infected with WNV and RVFV Clone 13 strain at titers of 1.6×108 and 1.33×107 plaque forming units (PFU/mL, respectively. We estimated viral infection, dissemination and transmission at 3, 7, 14 and 19 days post infection (dpi. Results showed that infection was higher for WNV than for RVFV from 3 dpi to 19 dpi. Viral dissemination and transmission started from 3 dpi for WNV; and only from 19 dpi for RVFV. Moreover, Cx. pipiens were able to excrete in saliva a higher number of viral particles of WNV (1028 ± 405 PFU/saliva at 19 dpi than RVFV (42 PFU/saliva at 19 dpi. Cx. pipiens from Lebanon are efficient experimental vectors of WNV and to a lower extent, RVFV. These findings should stimulate local authorities to establish an active entomological surveillance in addition to animal surveys for both viruses in the country.
Christensen-Dalsgaard, J; Narins, P M
and to sound from 40 dB SPL by increasing their spike rate. Best frequencies (BFs) ranged from 60 to 900 Hz, and only fibers with BFs below 500 Hz responded to vibrations. The fibers had identical BF's for sound and vibration. The saccular fibers had BFs ranging from 10 to 80 Hz with 22 fibers having BFs at 40......-50 Hz. The fibers responded to sound from 70 dB SPL and to vibrations from 0.01 cm/s2. 3. No differences in sensitivity, tuning or phase-locking were found between the two species, except that most BP-fibers in R. pipiens pipiens had BFs from 1.2 to 1.4 kHz, whereas those in L. albilabris had BFs from 2...
Šikutová, Silvie; Buňková, L.; Krejčí, E.; Halouzka, Jiří; Sanogo, Y. O.; Rudolf, Ivo
Roč. 169, 5-6 (2014), s. 348-352 ISSN 0944-5013 R&D Projects: GA ČR GA206/00/1234; GA ČR GA206/03/0726 Institutional support: RVO:68081766 Keywords : Spirochaete * Culex pipiens * Enzyme activity * SDS-PAGE * FAMEa Subject RIV: EE - Microbiology, Virology Impact factor: 2.561, year: 2014
Montgomery, Matthew J; Thiemann, Tara; Macedo, Paula; Brown, David A; Scott, Thomas W
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.
Abd Elmeguid, A.; Elmoursy, A.A.; Rouchdy, H.; Elzahraa, F.
Ultrastructural differences between differentiating myoblasts of 1-day old pupae and 2-day old pupae and between well developed flight muscles in newly emerged 1-day old and 2-day old and ageing 21-day old adult male Culex Pipiens were studied. Ageing mosquitoes showed various signs of deterioration, vocalization, fusion and disorientation of cristae. 6 figs
Farajollahi, Ary; Fonseca, Dina M; Kramer, Laura D; Marm Kilpatrick, A
The transmission of vector-borne pathogens is greatly influenced by the ecology of their vector, which is in turn shaped by genetic ancestry, the environment, and the hosts that are fed on. One group of vectors, the mosquitoes in the Culex pipiens complex, play key roles in the transmission of a range of pathogens including several viruses such as West Nile and St. Louis encephalitis viruses, avian malaria (Plasmodium spp.), and filarial worms. The Cx. pipiens complex includes Culex pipiens pipiens with two forms, pipiens and molestus, Culex pipiens pallens, Culex quinquefasciatus, Culex australicus, and Culex globocoxitus. While several members of the complex have limited geographic distributions, Cx. pipienspipiens and Cx. quinquefasciatus are found in all known urban and sub-urban temperate and tropical regions, respectively, across the world, where they are often principal disease vectors. In addition, hybrids are common in areas of overlap. Although gaps in our knowledge still remain, the advent of genetic tools has greatly enhanced our understanding of the history of speciation, domestication, dispersal, and hybridization. We review the taxonomy, genetics, evolution, behavior, and ecology of members of the Cx. pipiens complex and their role in the transmission of medically important pathogens. The adaptation of Cx. pipiens complex mosquitoes to human-altered environments led to their global distribution through dispersal via humans and, combined with their mixed feeding patterns on birds and mammals (including humans), increased the transmission of several avian pathogens to humans. We highlight several unanswered questions that will increase our ability to control diseases transmitted by these mosquitoes. Copyright © 2011 Elsevier B.V. All rights reserved.
Huang, Shaoming; Hamer, Gabriel L; Molaei, Goudarz; Walker, Edward D; Goldberg, Tony L; Kitron, Uriel D; Andreadis, Theodore G
Mosquitoes of the Culex pipiens complex are important vectors of West Nile virus in the United States. We examined the genetic variations of Cx. pipiens mosquitoes from Chicago, Illinois that were determined to be principally ornithophilic but exhibited a relatively higher inclination for mammalian hosts including humans. Microsatellite analysis of 10 polymorphic markers was performed on 346 engorged Cx. pipiens specimens with identified avian or mammalian blood meals. Our results indicated that there were no significant differences in allelic richness, the pattern of conformity to Hardy-Weinberg equilibrium, and linkage disequilibrium, nor was there overall genetic differentiation between specimens with avian- and mammalian-derived blood meals. However, Cx. pipiens form pipiens with mammalian- (including human-) derived blood meals had significantly higher ancestry (p 0.05) and the proportion of hybrids (p > 0.05) from Cx. quinquefasciatus (population from Harris Country, Texas). No temporal genetic variation was detected in accordance with the observation that there was no shift in blood feeding from birds to mammals. The results of this study in conjunction with regional host-feeding behavior suggest that the probability of genetic ancestry from Cx. pipiens f. molestus may predispose mosquitoes to feed more readily on mammals; however, the genetic mechanisms are unknown.
Lõhmus, Mare; Lindström, Anders; Björklund, Mats
Species in the Culex pipiens complex are common almost all over the world and represent important vectors for many serious zoonotic diseases. Even if, at the moment, many of the pathogens potentially transmitted by Cx. pipiens are not a problem in northern Europe, they may, with increasing temperatures and changing ecosystems caused by climate change, move northward in the future. Therefore, the question whether or not the Cx. pipiens populations in northern Europe will be competent vectors for them is of high importance. One way to estimate the similarity and the rate of contact between European Cx. pipiens populations is to look at the gene exchange between these populations. To test the genetic diversity and degree of differentiation between European Cx. pipiens populations, we used eight microsatellite markers in 10 mosquito populations originating from northern, central, and southern Europe. We found that three of the analyzed populations were very different from the rest of the populations and they also greatly differed from each other. When these three populations were removed, the variance among the rest of the populations was low, suggesting an extensive historic gene flow between many European Cx. pipiens populations. This suggests that infectious diseases spread by this species may not be associated with a certain vector genotype but rather with suitable environmental conditions. Consequently, we would expect these pathogens to disperse northward with favorable climatic parameters.
Full Text Available OBJETIVO: Observar detalhes morfológicos de ovos de Haemagogus leucocelaenus visualizados pela primeira vez por microscopia eletrônica de varredura (MEV e realizar morfometria das principais estruturas. MÉTODOS: Foram utilizados ovos de Hg. leucocelaenus provenientes de fêmeas capturadas na Reserva Biológica do Tinguá, RJ, sendo parte destinada à eclosão e outra ao processamento de MEV, dos quais três foram submetidos à análise morfométrica. O material foi fixado em glutaraldeído 2,5% e pós-fixado em tetróxido de ósmio 1%, ambos em tampão cacodilato de sódio 0.1M, pH 7.2, processado e observado ao MEV Jeol 5310. Medições foram realizadas com o auxílio do software de análise Semafore. RESULTADOS: Os ovos apresentaram contorno elíptico com aproximadamente 574 µm de comprimento e 169 µm de largura, sendo o índice do ovo (l/wratio 3,39 µm. O exocório é extremamente regular, possuindo ornamentação hexagonal e algumas vezes pentagonal. Nas células coriônicas, observaram-se tubérculos simetricamente dispostos com relação ao eixo longitudinal, e, no interior delas, tubérculos menores, individualizados, dispostos na periferia, e poucos agrupados no centro. A superfície do retículo coriônico não apresentou rugosidades. O aparelho micropilar apresenta colar proeminente, contínuo, com disco micropilar bem evidente. CONCLUSÕES: A ornamentação do exocório apresenta diferenças em relação aos tubérculos das células coriônicas e ao retículo coriônico externo entre os ovos de Hg. leucocelaenus comparados aos ovos de Hg. janthinomys e Hg. equinus, bem como com relação aos de Aedes aegypti, Ae. albopictus e Ae bahamensis.OBJECTIVE: To observe morphological details of the eggs of Haemagogus (Conopostegus leucocelaenus, seen for the first time via scanning electron microscopy (SEM, with morphometric analysis of the main structures. METHODS: Eggs of Hg. leucocelaenus were obtained from females captured in the Biological Reserve of Tinguá, State of Rio de Janeiro. Some of the eggs were kept for hatching and others underwent processing for scanning electron microscopy studies. Three eggs were submitted to morphometric analysis. The material was fixed in 2.5% glutaraldehyde and postfixed in 1% osmium tetroxide, both in 0.1M, pH 7.2 sodium cacodylate buffer, then dehydrated in ethanol and dried using the critical point method. This was then set up on metallic supports, covered with gold and observed using the Jeol 5310 scanning electron microscope. Measurements were made with the aid of the Semafore analysis software coupled to the electron microscope. RESULTS: The eggs presented elliptical outlines of approximately 574 mm in length and 169 mm in width, with an egg index (l/w ratio of 3.39 mm. The exochorion was extremely regular and had ornamentation that was usually hexagonal but sometimes pentagonal. Tubercles were observed on the chorionic cells, symmetrically arranged in relation to the longitudinal axis. Inside the cells, there were smaller, individualized tubercles, some arranged peripherally and others grouped to a greater or lesser extent in the center. The surface of the chorionic reticulum did not present rugosity. The micropylar apparatus was formed by a prominent continuous collar of 8.32 mm in thickness, with a slightly irregular surface. The micropylar disk was very evident, and was continuous with the collar. The micropyle was seen at the center of this disk, measuring 1.6 mm and with a micropylar apparatus of 27.3 mm in diameter. CONCLUSIONS: The ornamentation of the exochorion presents differences in relation to the tubercles of chorionic cells and the external chorionic reticulum between the eggs of Hg. Leucocelaenus, in comparison with the eggs of Hg. janthinomys and Hg. equinus, and also in relation to those of Aedes aegypti, Ae. albopictus and Ae bahamensis. In various aspects, the eggs of Hg. leucocelaenus have more resemblance to those of Hg. Equinus than those of Hg. janthinomys, with greater differences presented in relation to the eggs of Hg. spegazzinii and Hg. lucifer.
Gustavo C. Rossi
Full Text Available Se presentan 21 nuevos registros de especies y se amplía la distribución de otras 12 especies de los géneros Anopheles Meigen, Coquillettidia Dyar, Culex L., Haemagogus Williston, Ochlerotatus Lynch Arribalzaga, Onirion Harbach y Peyton, Orthopodomyia Theobald, Psorophora Robineau-Desvoidy, Sabethes Robineau-Desvoidy, Stegomyia Theobald, Toxorhynchites Theobald. Se incluyen comentarios y cambios de estatus para especies de Howardina Theobald, Ochlerotatus y Lutzia (Theobald. Actualmente, en la Argentina se hallan presentes 226 especies distribuidas en 23 géneros.Twenty one new records and 12 new distributional records of species of the genus Anopheles Meigen, Coquillettidia Dyar, Culex L., Haemagogus Williston, Ochlerotatus Lynch Arribalzaga, Onirion Harbach & Peyton, Orthopodomyia Theobald, Psorophora Robineau-Desvoidy, Sabethes Robineau-Desvoidy, Stegomyia Theobald, Toxorhynchites Theobald are reported. Comments and changes in the status of species of Howardina Theobald, Ochelrotatus and Lutzia Theobald are included. Currently, in Argentina are present 226 species distributed in 23 genera.
Maria Goreti Rosa-Freitas
Full Text Available Anopheles (Nyssorhynchus deaneorum sp. n. is described from specimens collected in Guajará-Mirim, Rondônia state and Rio Branco, Acre state, Brazil, on human and animal baits, inside dwellings and from the progenies of engorged females. A detailed description of the shape of egg, external appearance of adult female and male, genitalias, female cibarial armature and complete chaetotaxy of pupa and larva show that it can be distinguished from Anopheles albitarsis from the type-locality and other areas by the paler general external appearance of the adult, the posterolateral tufts of scales, on the female abdominal terga and the branching of the outer anterior clypeal seta (3-C of the fourth instar larva (as shown in illustrations. If species can also be distinguished from An. albitarsis from the type locality by the allele frequencies at 11 enzymic loci as represented by Nei's Genetic Distance.Anopheles (Nyssorhynchus deaneorum sp. n. é descrito a partir de exemplares coletados em capturas comparativas no intradomicílio e no peridomicílio usando isca humana e animal e progênies de fêmeas ingurgitadas, em Guarajá-Mirim, Rondônia e Rio Branco, Acre. A descrição detalhada do ovo, dos adultos fêmea e macho, inclusive cibário da fêmea, genitália, quetotaxia da pupa e da larva e seu perfil isoenzimático, mostram que esse mosquito pode ser distinguido do Anopheles albitarsis na fase adulta pelo aspecto geral mais claro, pela presença de tufos laterais de escamas escuras somente a partir do quarto ou quinto tergitos abdominais, enquanto em albitarsis começam no terceiro e, na fase larvária, pela ramificação das cerdas clipeais anteriores externas, que em albitarsis são aciculadas (como mostram as ilustrações, bem como pelo padrão isoenzimático.
Walter R. Almirón
Full Text Available Con el propósito de estudiar la preferencia de hospedadores vertebrados por mosquitos hembras, durante 2 períodos octubre-abril (primavera-verano, se realizaron muestreos cada 15 días en Córdoba y Cosquín (Argentina. Se utilizaron trampas de latón con cebo animal: anfibios (sapos, aves (pollos, mamíferos (conejos y reptiles (tortugas. El 92,9% de los especímenes recolectados pertenecen al género Culex, mientras que un 7,0% corresponde a Aedes y el 0,02% restante a Psorophora ciliata, única especie que se capturó de ese género. En trampas con pollo se recolectó el mayor número de hembras (68,7%, siguiendo en orden las trampas con conejos (29,9%, con tortugas (0,8% y con sapos (0,5%, por lo tanto, la mayoría de los mosquitos entraron en las trampas con hospedadores homeotermos. Culex dolosus se alimentó sobre todos los cebos, mientras que Cx. acharistus, Cx. chidesteri y Cx. quinquefasciatus se alimentaron sobre pollos, conejos y tortugas; Ae. albifasciatus, Ae. scapularis, Cx. bidens y Cx. coronator lo hicieron sobre ambos hospedadores homeotermos; Cx. apicinus, Cx. maxi, Cx. saltanensis y Cx. spinosus se alimentaron solamente sobre pollos y Ps. ciliata sobre conejos.Com o propósito de estudar a preferência de mosquitos fêmeas por hospedeiros vertebrados, realizaram-se amostragens quinzenais nas cidades de Córdoba e Cosquín (Argentina, durante o período de outubro a abril (primavera-verão, por dois anos consecutivos. Utilizaram-se armadilhas com iscas animais: anfíbios, aves, mamíferos e répteis. Dos espécimes coletados, 92,9% pertenciam ao gênero Culex, 7,0% a Aedes e 0,02% a Psorophora ciliata, única espécie coletada desse gênero. A maior proporçãoo de fêmeas (68,7% foi capturada em armadilhas iscadas com galinhas, seguindo-se em ordem as armadilhas com coelhos (29,9%, com tartarugas (0,8% e com anfíbios (0,05%. Assim, a maioria dos mosquitos foi coletada em armadilhas com hospedeiros homeotermos. Culex dolosus alimentou-se em todas as iscas, enquanto que Cx. acharistus, Cx. chidesteri e Cx. quinquefasciatus em galinhas, coelhos e tartarugas; Ae. albifasciatus, Ae. scapularis, Cx. bidens e Cx. coronator fizeram-no em ambos hospedeiros homeotermos; Cx. apicinus, Cx. maxi, Cx. saltanensis e Cx. spinosus alimentaram-se apenas em galinhas e Ps. ciliata em coelhos.In order to study the host preference of female mosquitoes, samples were taken fortnightly in Cordoba and Cosquin (Argentina, during October-April of two consecutive years. Four different vertebrates were used in baited-can traps: frogs, chickens, rabbits and turtles. The genus Culex acounted for 92.9% of the specimens collected, Aedes for 7.0% and Psorophora ciliata 0.02%. The highest proportion of females were collected in chicken traps (68.7%, followed by rabbit traps (29.9%, turtles (0.8% and frogs (0.5%, thus the majority of the mosquitoes were collected in traps with homeotermous hosts. Only Culex dolosus fed on all the hosts. Culex acharistus, Cx. chidesteri and Cx. quinquefasciatus fed on chickens, rabbits and turtles. Aedes albifasciatus, Ae. scapularis, Cx. bidens and Cx. coronator fed on both homeotermous hosts. Culex apicinus, Cx. maxi, Cx. saltanensis and Cx. spinosus fed only on chickens and Ps. ciliata only on rabbits.
Almério de Castro Gomes
Full Text Available As atividades antrópicas levadas a cabo em zona rural têm afetado o comportamento de mosquitos Culex (Culex, motivo pelo qual foi realizada investigação para observar seus abrigos naturais em área de pastagem, margem e interior de matas primitivas ou residuais. Foram escolhidas três localidades com características mesológicas diferenciadas pelo tipo de atividade humana, todas situadas na região do Vale do Ribeira, Estado de São Paulo, Brasil. As espécies mais abundantes foram Cx. mollis (28,0%, Cx. declarator (25,0%, Cx. lygrus (13,0% e Cx. coronator (9,6%. O conjunto Cx. Bidens + Cx. dolosus + Cx. chidesteri, de hábito mais urbanizado, foi capturado em número muito reduzido. Com relação aos ambientes pesquisados, a mata contribuiu com 2.281 indivíduos (71,4%, sugerindo ser local de abrigo preferido pelo grupo, exceto para Cx. quinquefasciatus. Avaliou-se o potencial de domiciliação de cada espécie e suas conseqüências para a população humana.The human activities carried out in rural zones have been affeecting the behavior of mosquitoes of the Culex (Culex subgenera, which was the reason for undertaking this investigation with a view to registering data on the natural resting places in pastures and on the edge of or within primitive and residual forest areas. Three localities with different mesological conditions, as to type of human activity, all them situated in the Ribeira Valley region of S. Paulo State, Brazil, were chosen. The species most abundantly found were Cx. mollis (28.0%, Cx. declarator (25.0%, Cx. lygrus (13.0% and Cx. coronator (9.6%. The collection of mosquitoes Cx. bidens + Cx. dolosus + Cx. chidesteri, known to be more urban, was much smaller than that of any other species of the group. With reference to outdoor environments, woodland contributed with 2,281 individuals (71.4% suggesting their preference for this resting place, except for Cx. quinquefasciatus. Results are evaluated for the determination of the potential domicilation of each species and consequence of the same for the human population.
Gossling, J; Loesche, W J; Nace, G W
The bacteria in the large intestines of 10 northern leopard frogs (Rana pipiens) were enumerated and partially characterized. Four nonhibernating frogs were collected in the summer, four hibernating frogs were collected in the winter, and two frogs just emerged from hibernation were collected in the spring. All frogs had about 10(10) bacteria per g (wet weight) of intestinal contents and about 10(9) bacteria per g (wet weight) of mucosal scraping, although the counts from the winter frogs wer...
Mushet, David M.; Euliss, Ned H.; Chen, Yongjiu; Stockwell, Craig A.
In contrast to most local amphibian populations, northeastern populations of the Northern Leopard Frog (Lithobates pipiens) have displayed uncharacteristically high levels of genetic diversity that have been attributed to large, stable populations. However, this widely distributed species also occurs in areas known for great climatic fluctuations that should be reflected in corresponding fluctuations in population sizes and reduced genetic diversity. To test our hypothesis that Northern Leopard Frog genetic diversity would be reduced in areas subjected to significant climate variability, we examined the genetic diversity of L. pipiens collected from 12 sites within the Prairie Pothole Region of North Dakota. Despite the region's fluctuating climate that includes periods of recurring drought and deluge, we found unexpectedly high levels of genetic diversity approaching that of northeastern populations. Further, genetic structure at a landscape scale was strikingly homogeneous; genetic differentiation estimates (Dest) averaged 0.10 (SD = 0.036) across the six microsatellite loci we studied, and two Bayesian assignment tests (STRUCTURE and BAPS) failed to reveal the development of significant population structure across the 68 km breadth of our study area. These results suggest that L. pipiens in the Prairie Pothole Region consists of a large, panmictic population capable of maintaining high genetic diversity in the face of marked climate variability.
Hai-qunCao; Yong-deYue; Zhen-huaPeng; Ri-maoHua; FengTang
The extracts from 7 species of bamboo were tested for larvicidal activity against Culex pipiens pallens. At the tested concentration, the extracts of selected bamboo had different degree of toxic effects on the fourth instar larvae of Culex pipiens pallens. Among them,the extracts of Pleioblastus juxianensis, Brachystachyum albostriatum, Phyllostachys platyglossa and Pleioblastus amarus were found to be effective with LC50values at 24h of 30.65mg/L,53.94mg/L, 41.21 mg/L and 54.49 mg/L respectively, against Culex pipiens pallens larvae. The extract of Pleioblastus juxianensis by Soxhlet method showed stronger activity than the extract obtained by interval-shaking, the LC50 of which were 30.65 mg/L and 48.34 mg/L, respectively.The diethyl ether extract of Pleioblastus juxianensis exhibited better larvicidal activity than the methanol extract and the petroleum ether extract. The results would help to provide the basis for the study of environment acceptable pesticide for mosquito control, and also help to comprehensively utilize the source of bamboo.
Bonneau, Manon; Atyame, Celestine; Beji, Marwa; Justy, Fabienne; Cohen-Gonsaud, Martin; Sicard, Mathieu; Weill, Mylène
Culex pipiens mosquitoes are infected with Wolbachia (wPip) that cause an important diversity of cytoplasmic incompatibilities (CIs). Functional transgenic studies have implicated the cidA-cidB operon from wPip and its homolog in wMel in CI between infected Drosophila males and uninfected females. However, the genetic basis of the CI diversity induced by different Wolbachia strains was unknown. We show here that the remarkable diversity of CI in the C. pipiens complex is due to the presence, in all tested wPip genomes, of several copies of the cidA-cidB operon, which undergoes diversification through recombination events. In 183 isofemale lines of C. pipiens collected worldwide, specific variations of the cidA-cidB gene repertoires are found to match crossing types. The diversification of cidA-cidB is consistent with the hypothesis of a toxin-antitoxin system in which the gene cidB co-diversifies with the gene cidA, particularly in putative domains of reciprocal interactions.
Full Text Available Mohamed EI Badawy,1 Nehad EM Taktak,2 Osama M Awad,2 Souraya A Elfiki,2 Nadia E Abou El-Ela2 1Department of Pesticide Chemistry and Technology, Faculty of Agriculture, 2Department of Tropical Health, High Institute of Public Health, Alexandria University, Alexandria, Egypt Abstract: Efficacy of spinosad and malathion loaded in eco-friendly biodegradable formulations was evaluated for controlling Culex pipiens larvae. Malathion (organophosphorus larvicide and spinosad (naturally derived insecticide were loaded on chitosan/alginate/gelatin capsules. Capsules were characterized by size measurement, scanning electron microscopy, Fourier transform infrared spectroscopy, and water uptake. In vitro release kinetics of the larvicides was studied in the running and stagnant water. Biochemical studies on the larvae treated with technical and formulated insecticides were also demonstrated. The results indicated that the released spinosad was active for a long time up to 48 and 211 days in the running and stagnant water, respectively. However, the capsules loaded with malathion showed larvicidal activity for 20 and 27 days in the running and stagnant water, respectively. Technical and formulated malathion and spinosad had an inhibition effect on acetylcholinesterase, carboxylesterase, and glutathione S-transferase. The results proved that the prepared capsules consisting of biodegradable polymers containing larvicides could be effective as controlled-release formulation against C. pipiens larvae for a long period. Keywords: chitosan capsules, larvicide, controlled-release formulation, swelling, mosquitocidal activity, Culex pipiens, biochemical study
Bouhsira, E; Fysikopoulos, A; Franc, M
A controlled clinical trial was carried out to assess the effectiveness of pyriprole, metaflumizone combined with amitraz, and fipronil-(S)-methoprene commercial spot-on products in preventing adult female Culex pipiens pipiens from feeding on dogs. Twenty-four beagle dogs were tested for their attractiveness to the mosquitoes and ranked accordingly to produce four groups of equivalent sensitivity to mosquitoes; six were treated with the pyriprole spot-on, six with the metaflumizone combined with amitraz spot-on, six with the fipronil-(S)-methoprene spot-on, and six were left untreated. All the dogs were challenged with 50 unfed adult female Culex in cages for one hour seven days before the treatment, and one and seven days after it. The mosquitoes were checked for blood feeding after one hour and for mortality 24 hours after they had been released into the cages. There was a significant reduction in the number of engorged mosquitoes only with the fipronil-(S)-methoprene product and there were significantly more dead mosquitoes with this product and the pyriprole product, but their effects were too small for them to be recommended for use in a dirofilariosis prevention programme.
Levine, N D; Nye, R R
In a survey of blood and other tissue parasites from 137 leopard frogs, Rana pipiens complex, purchased from 13 commercial vendors in 8 states in the United States, Trypanosoma pipientis was found in 2 R. p. berlandieri, Toxoplasma ranae in 1 R. pipiens, Isospora lieberkuehni in 1 leopard frog, Haemogregarina magna in 44, Lankesterella minima in 3, Leptotheca ohlmacheri in 3 and microfilariae of Foleyella sp. in 6. The report of I. lieberkuehni is presumably a new host record. Haemogregarina temporariae (Nöller,, 1920) nov. comb. is established as a new combination for Nematopsis temporariae.
Pfeiler, E; Markow, T A
Mitochondrial DNA sequence data from the control region and 12S rRNA in leopard frogs from the Sierra El Aguaje of southern Sonora, Mexico, together with GenBank sequences, were used to infer taxonomic identity and provide phylogenetic hypotheses for relationships with other members of the Rana pipiens complex. We show that frogs from the Sierra El Aguaje belong to the Rana berlandieri subgroup, or Scurrilirana clade, of the R. pipiens group, and are most closely related to Rana magnaocularis from Nayarit, Mexico. We also provide further evidence that Rana magnaocularis and R. yavapaiensis are close relatives.
Merrell, D J
Data are presented for 2,393 progeny from a number of crosses related to a study in ecological genetics of the Burnsi and Kandiyohi polymorphisms in natural populations of the leopard frog, Rana pipiens. No significant differences in viability were found between wild-type homozygotes (+/+) and Burnsi heterozygotes (B/+) or homozygotes (B/B). Similarly, no difference in viability was found between wild-type (+/+) and Kandiyohi heterozygotes (K/+) and homozygotes (K/K). However, there appears to be slight reduction in viability of the double dominant heterozygote (B/+; K/+) in comparison with (+/+), (B/+), and (K/+) progeny from the same cross.-The Kandiyohi heterozygotes (K/+) appeared to have a more rapid rate of development from fertilization through metamorphosis than wild-type (+/+) or Burnsi (B+/) or Burnsi-Kandiyohi heterozygotes (B+K/+). Since Kandiyohi is associated primarily with the prairie habitat (Merrell 1965), this finding suggests that the adaptive advantage of Kandiyohi lies in the more rapid rate of development of frogs carrying this gene, enabling them to complete metamorphosis before the prairie breeding ponds dry up.-Data are presented from crosses involving dorsal spot number. The results suggest that heredity plays a role in the determination of dorsal spot number but that non-genetic influences are also of considerable importance.-The results of these crosses are discussed with respect to their bearing on the formation of pigment patterns in Rana pipiens. From the available data it is clear that the pigment pattern in Rana pipiens is a complex trait influenced by major gene loci, by modifying genes, and by environmental effects. The relative importance of these factors varies depending on the particular combination of genetic and environmental conditions.
Rianka P M Vloet
Full Text Available Rift Valley fever virus (RVFV is a mosquito-borne bunyavirus of the genus Phlebovirus that is highly pathogenic to ruminants and humans. The disease is currently confined to Africa and the Arabian Peninsula, but globalization and climate change may facilitate introductions of the virus into currently unaffected areas via infected animals or mosquitoes. The consequences of such an introduction will depend on environmental factors, the availability of susceptible ruminants and the capacity of local mosquitoes to transmit the virus. We have previously demonstrated that lambs native to the Netherlands are highly susceptible to RVFV and we here report the vector competence of Culex (Cx. pipiens, the most abundant and widespread mosquito species in the country. Vector competence was first determined after artificial blood feeding of laboratory-reared mosquitoes using the attenuated Clone 13 strain. Subsequently, experiments with wild-type RVFV and mosquitoes hatched from field-collected eggs were performed. Finally, the transmission of RVFV from viremic lambs to mosquitoes was studied.Artificial feeding experiments using Clone 13 demonstrated that indigenous, laboratory-reared Cx. pipiens mosquitoes are susceptible to RVFV and that the virus can be transmitted via their saliva. Experiments with wild-type RVFV and mosquitoes hatched from field-collected eggs confirmed the vector competence of Cx. pipiens mosquitoes from the Netherlands. To subsequently investigate transmission of the virus under more natural conditions, mosquitoes were allowed to feed on RVFV-infected lambs during the viremic period. We found that RVFV is efficiently transmitted from lambs to mosquitoes, although transmission was restricted to peak viremia. Interestingly, in the mosquito-exposed skin samples, replication of RVFV was detected in previously unrecognized target cells.We here report the vector competence of Cx. pipiens mosquitoes from the Netherlands for RVFV. Both
Full Text Available Field studies were conducted to determine the mosquito species richness in the urban area of Greater Puntarenas in Costa Rica. Two cross-sectional entomological surveys were performed in seven localities of Puntarenas: one survey was performed during the wet season and the other during the dry season. The sections evaluated were determined by applying a stratified cluster sampling method using satellite imagery, and a sample of 26 cells (100x100m was selected for the study. The number of cells per locality was proportional to the area of each locality. The presence of mosquito larvae and pupae in water-filled artificial and natural containers was determined in each cell. Infestation was expressed as a diversity index per type of container (Ii. Eight types of larvae were identified (Aedes aegypti, Culex quinquefasciatus, Culex interrogator, Culex nigripalpus, Culex corniger, Culex tarsalis, Limatus durhamii and Toxorhynchites theobaldi and in two cases it was only possible to identify the genus (Culex sp. and Uranotaenia sp.. A. aegypti was the most common species followed by C. quinquefascitus. Diversity of wet environments can explain the co-occurrence of various culicid species in some localities. Although A. aegypti is the only documented disease vector in the area, C quinquefasciatus, C. nigripalpus, and the other species of Culex could be considered potential vectors of other pathogens. The presence and ecology of all mosquito species should be studied to optimize surveillance and prevention of dengue and to prevent the emergence of other mosquito-transmitted diseases. Rev. Biol. Trop. 57 (4: 1223-1234. Epub 2009 December 01.La riqueza de especies de mosquitos urbanos de la Gran Puntarenas (Puntarenas, Costa Rica fue evaluada por medio de análisis larvales. Dos encuestas entomológicas fueron realizadas en siete localidades de la Gran Puntarenas durante un año. Una de las encuestas fue realizada en la estación seca y la otra se llevó a cabo en la estación lluviosa. Las áreas evaluadas fueron determinadas aplicando un muestreo por conglomerados usando imágenes satelitales. Veintiséis celdas (100x100m fueron seleccionadas en las comunidades elegidas y en éstas fueron realizadas las evaluaciones entomológicas. El número de celdas por localidad fue proporcional al área de cada localidad. La presencia de larvas o pupas fue determinada en contenedores con agua (naturales y artificiales. La infestación se expresó por medio índices de diversidad por tipo de contenedor (Ii. La asociación entre contenedores positivos por especies particulares y localidades fue evaluada mediante pruebas de Chi-cuadrado (α=0.05. Ocho de los tipos de larvas encontrados fueron identificados a nivel de especie (Aedes aegypti, Culex quinquefasciatus, C. interrogator, C. nigripalpus, C. corniger, C. tarsalis, Limatus durhamii, Toxorhynchites theobaldi y dos se identificaron a nivel de género (Culex sp., y Uranotaenia sp. A aegypti fue la especie más frecuente en la Gran Puntarenas. C. quinquefasciatus fue la segunda en frecuencia. Algunas localidades como Carrizal mostraron una importante diversidad de ambientes acuáticos que promovieron la ocurrencia de diferentes especies de culícidos. La distribución de los contenedores positivos por localidad en función de las especies encontradas no mostró homogeneidad (p>0.05. Aunque A. aegypti es el único vector documentado en la zona, otros mosquitos como C. quinquefasciatus y otras especies de Culex podrían ser potenciales vectores de otros agentes etiológicos (virus del Nilo occidental, virus de la encefalitis de San Luis, virus de la encefalitis equina del este. Los resultados obtenidos indican la necesidad considerar la presencia y la ecología de todas las especies de mosquitos en las campañas preventivas por dengue en el área, y en la vigilancia epidemiológica por otras enfermedades transmitidas por mosquitos.
Gornostaeva, R M
Among females and larvae of mosquitoes collected in 1969, 1981-1984 in the area of the Sayan-Shushenskoe hydroelectric power station (140 km up the Yenisei River from the Abakan city) 5 genera and 30 species were recorded. Based on recent collections and reference data (Gornostaeva e. a., 1969; Gornostaeva, Danilov, 1986) the fauna of the region in question includes 31 species of mosquitoes (Anopheles--1, Culiseta--2, Coquillettidia--1, Aedes--22, Culex--5).
Full Text Available INTRODUCTION: Findings of immature forms of Coquillettidia venezuelensis in temporary breeding sites, without the presence of aquatic plants or other submerged plant tissue are reported. METHODS: A systematic scooping technique to collect specimens was used at the breeding site. RESULTS: Immature forms of Coquillettidia venezuelensis, Anopheles rangeli, An. evansae and Culex sp. were collected from areas of the hydroelectric power station of São Salvador, State of Goiás. CONCLUSIONS This is a novel finding relating to the bioecology of Cq. venezuelensis, a species of medical interest that has been found naturally infected with arboviruses, including Oropouche and West Nile virus.
Tejerina, Edmundo Fabricio; Almeida, Francisco Felipe Ludueña; Almirón, Walter Ricardo
Life statistics of four Aedes aegypti subpopulations from the subtropical province of Misiones were studied during autumn and winter, under semi-natural conditions, coming from the localities of Posadas (SW), San Javier (SE), Bernardo de Irigoyen (NE) and Puerto Libertad (NW). The eastern subpopulations are geographically separated by the central mountain system of the province from the western subpopulations. High percentages of larval and pupal survival (97-100%) were recorded, and no significant differences were detected among the four subpopulations. Larvae and pupae lasted approximately 8 days to complete their development, no significant differences being detected among the four subpopulations studied. Sex ratio recorded did not differ significantly from 1:1. Male longevity did not show difference among the different subpopulations, but female longevity was remarkably different among the four subpopulations (F=16.27; d.f.=(3;8); P=0.0009), ranging among 11.45 days for San Javier and 57.87 days for Posadas. Fecundity also varied considerably among subpopulations, the greatest number (307.44 eggs/female) being recorded for Posadas (F=4.13; d.f.=(3;8); P=0.04). Ae. aegypti females of the western subpopulations lived longer than the eastern subpopulations studied, therefore, the risk of dengue outbreak would be greater on the Misiones Province border with Paraguay.
Qualls, Whitney A; Xue, Rui De; Beier, John C; Müller, Günter C
The international trade of lucky bamboo (Dracaena sanderiana [Asparagaceae]) is responsible for certain introductions of the exotic species Aedes albopictus (Skuse) in California and the Netherlands. Understanding the association of this species with lucky bamboo and other ornamental plants is important from a public health standpoint. The aim of this study was to investigate the importance of indoor ornamental plants as sugar sources for adult A. albopictus. If exposed to D. sanderiana, bromeliad (Guzmania spp. hybrid [Bromeliaceae]), Moses-in-the-cradle (Rhoeo spathacea [Commelinaceae]), 10 % sucrose solution, and a negative water control as the only nutrient source, adult female A. albopictus mean survival time was 12, 7, 6, 15, and 4 days, respectively. Mean survival times for adult males were not significantly different (P > 0.05) from the females and were 10, 7, 6, 14, and 3 days, respectively. Combined male and female survival times were not significantly different on lucky bamboo compared to survival times on a 10 % sucrose control. Based on our findings, A. albopictus can readily survive long enough to complete a gonotrophic cycle and potentially complete the extrinsic incubation period for many arboviruses when only provided access to lucky bamboo plants or possibly other common ornamentals. Vector control professionals should be aware of potential in-home infestations and public health concerns associated with mosquito breeding and plant tissue feeding on ornamental plants.
Maria Anice Mureb Sallum
Full Text Available Anopheles galvaoi, a member of the subgenus Nyssorhynchus, is redescribed based on morphological characters of the adults male and female, fourth-instar larva and pupa. Female, male genitalia, larval and pupal stages are illustrated. Data about medical importance, bionomics, and distribution are given based on literature records. Adult female of An. galvaoi can be easily misidentified as An. benarrochi Gabaldón and An. aquasalis Curry. A few characters are indicated for identifying female and immatures of An. galvaoi. Phylogenetic relationships among An. galvaoi and six other species of the Oswaldoi Subgroup are estimated using COII mtDNA and ITS2 rDNA gene sequences. Lectotype of An. galvaoi, an adult female from Rio Branco, State of Acre, is invalidated.
Seidel, Bernhard; Silbermayr, Katja; Kolodziejek, Jolanta; Indra, Alexander; Nowotny, Norbert; Allerberger, Franz
On July 15, 2012, adult Anopheles hyrcanus (Pallas 1771) mosquitoes were caught next to a farm barn near Rust, Burgenland, close to Lake Neusiedl National Park in eastern Austria. Six weeks later, adults of this invasive species were also found in a sheep shelter outside the village of Oggau and another 2 weeks later, in a horse barn in Mörbisch. The morphological typing was confirmed genetically by amplification and sequencing of a 1,404-bp-long fragment within the 5.8S ribosomal RNA gene, the internal transcribed spacer 2, and the 28S ribosomal RNA gene. Out of two A. hyrcanus pools analyzed, one was found positive for Plasmodium sp. A 460-bp-long sequence within the mitochondrial cytochrome b region revealed 100 % identity to a sequence of a Plasmodium parasite identified in a New Zealand bellbird (Anthornis melanura). The Austrian finding sites are close to the Hungarian border. In Hungary, the occurrence of A. hyrcanus was already reported in 1963. A. hyrcanus is considered the most important potential vector of malaria in southern France today. In Austria, sporadic autochthonous malaria cases could emerge, caused by immigration from malaria-endemic countries and heavy tourism. However, the broad population coverage of the Austrian health care system makes the reestablishment of endemic areas for malaria unlikely.
Full Text Available In 2014, Guangzhou City, South China, suffered from its worst outbreak of dengue fever in decades. Larval mosquito habitat surveillance was carried out by using android mobile devices in four study sites in May 2015. The habitats with larval mosquitoes were recorded as photo waypoints in OruxMaps or in videos. The total number of potential mosquito habitats was 342, of which 166 (49% were found to have mosquito larvae or pupae. Small containers were the most abundant potential habitats, accounting for 26% of the total number. More mosquito larvae and pupae, were found in small containers than in other objects holding water, for example, potted or hydroponic plants (p < 0.05. Mosquito larvae were collected from all plastic road barriers, used tires, and underground water. Aedes albopictus larvae were found from small and large containers, stumps, among others. The overall route index (RI was 11.3, which was 14.2 times higher than the grade C criteria of the National Patriotic Health Campaign Committee (NPHCC, China. The higher RIs were found from the bird and flower markets, schools, and underground parking lots. The results indicated that Android mobile devices are a convenient and useful tool for surveillance of mosquito habitats, and the enhancement of source reduction may benefit the prevention and control of dengue vector mosquitoes.
Reegan, Appadurai Daniel; Paulraj, Michael Gabriel; Ignacimuthu, Savarimuthu
We show for the first time that the midgut of Culex quinquefasciatus (Say) mosquito larvae harbors halotolerant bacteria. The midgut from field collected Cx. quinquefasciatus larvae were dissected under aseptic conditions, homogenized and plated on LB agar medium with 2% (w/v) NaCl. Two different colonies were successfully isolated and bacterial isolates were identified by 16S rRNA sequences. The halotolerant bacterial isolates were: Halobacillus litoralis (CxH1) and Staphylococcus cohnii (CxH2). The gene sequence of these isolates has been deposited in GenBank (JN016804 and JN183986). These halotolerant bacteria grew in the absence of salt (0%) as well as in the presence of relatively high salt concentrations in culture medium (20%), and grew best in the presence of 8-10% (w/v) NaCl. H. litoralis and S. cohnii showed growth up to 18 and 20% (w/v) NaCl, respectively. Optimum growth temperatures for both the bacteria were between 30-37 degrees C. H. litoralis was resistant to the antibiotics oxacillin, penicillin, polymixin and S. cohnii was resistant to the antibiotic oxacillin.
Harry C Evans
Full Text Available Classical biological control has been used extensively for the management of exotic weeds and agricultural pests, but never for alien insect vectors of medical importance. This simple but elegant control strategy involves the introduction of coevolved natural enemies from the centre of origin of the target alien species. Aedes aegypti - the primary vector of the dengue, yellow fever and Zika flaviviruses - is just such an invasive alien in the Americas where it arrived accidentally from its West African home during the slave trade. Here, we introduce the concept of exploiting entomopathogenic fungi from Africa for the classical biological control of Ae. aegypti in the Americas. Fungal pathogens attacking arthropods are ubiquitous in tropical forests and are important components in the natural balance of arthropod populations. They can produce a range of specialised spore forms, as well as inducing a variety of bizarre behaviours in their hosts, in order to maximise infection. The fungal groups recorded as specialised pathogens of mosquito hosts worldwide are described and discussed. We opine that similar fungal pathogens will be found attacking and manipulating Ae. aegypti in African forests and that these could be employed for an economic, environmentally-safe and long-term solution to the flavivirus pandemics in the Americas.
Rosero-García, Doris; Rúa-Uribe, Guillermo; Correa, Margarita M; Conn, Jan E; Uribe-Soto, Sandra
Information about mosquito ecology in the high mountain ecosystems of the Neotropical region is sparse. In general, few genera and species have been reported in these ecosystems and there is no information available on habitats and the mosquitoes occupying them. In the present study, specimens collected from NW Colombia in HME were grouped using larval habitat data via an Operational Taxonomic Unit (OTU) determination. A total of 719 mosquitoes was analyzed belonging to 44 OTUs. The analysis considered habitat features and clustered the specimens into six groups from A-F. Five of these included species from different genera, suggesting common habitat requirements. Group E with four genera, seven subgenera, and six species occupied the highest areas (above 3,000 m), whereas three groups (B, D, F) were detected at lower altitudes (1,960-2,002 m). Bromeliads were the most common larval habitat, with 47% (335/719) of the specimens; five genera, six subgenera, and eight species were identified and classified into 66% (29/44) of the OTUs. This work showed some similarities to the habitat requirements and provides a grouping system that constitutes an important baseline for the classification of mosquito fauna from high mountain ecosystems according to altitude and larval habitat. © 2018 The Society for Vector Ecology.
Kramer, V L; Carper, E R; Beesley, C; Reisen, W K
Two mark-release-recapture studies were conducted along the Sacramento-San Joaquin River Delta in northern California to describe the population ecology and dispersal pattern of Aedes dorsalis (Meigen). Immature Ae. dorsalis were collected from saline tidal marshes, reared to adults, marked, and released. Recapture grids during the July and September studies were within 8.0 and 2.4 km of the release sites, and recapture rates were 0.1 and 1.2%, respectively. The longest recorded flight was 5.8 km, and mosquitoes were recaptured up to 15 d after release. In September, 84% of the marked mosquitoes were recaptured within 2.0 km of the release site, and the mean dispersal distance was 1.9 km. Marked mosquitoes flew predominantly downwind to the east. There was no evidence that Ae. dorsalis traversed the 1.6-km-wide river from Contra Costa to Solano County. Temporal and spatial recapture patterns indicated a possible short-range migration pattern from oviposition sites to upland host-seeking areas. Changes in the recapture rate with cohort age delineated a 7-d gonotrophic cycle during September.
Kho, Elise A; Hugo, Leon E; Lu, Guangjin; Smith, David D; Kay, Brian H
In order to assess the broad-scale applicability of field releases of Wolbachia for the biological control of insect-transmitted diseases, we determined the relationship between the larval diet of Aedes aegypti L. mosquitoes infected with Wolbachia strains and their susceptibility to dengue virus (DENV) infection via intrathoracic injection and oral inoculation. Larvae were reared on diets that varied in the quantity of food which had the effect of modifying development time and adult body size. Wolbachia wMel infection was associated with highly significant reductions in dengue serotype 2 (DENV-2) infection rates of between 80 and 97.5% following intrathoracic injection of adults emerging from three diet levels. Reductions were 100% in two diet level treatments following oral inoculation. Similarly, wMelPop infection was associated with highly significant reductions in DENV-2 infection rates of between 95 and 100% for intrathoracic injection and 97.5 and 100% for oral inoculation across diet level treatments. Larval diet level had no significant effect on DENV-2 infection rates in the presence of Wolbachia infection in mosquitoes that were intrathoracically injected with the virus. This indicates that the effectiveness of Wolbachia on vector competence disruption within Ae. aegypti is unlikely to be compromised by variable larval nutrition in field settings. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
In this study, chemical extracts of Jatropha curcas, Hyptis suaveolens, Abutilon indicum, and Leucas aspera were tested for toxicity to larvae of the filariasis vector Culex quinquefasciatus. Respective median lethal concentrations (LC50) for hexane, chloroform, ethyl acetate, and methanol extracts...
Bartlett-Healy, Kristen; Unlu, Isik; Obenauer, Peter; Hughes, Tony; Healy, Sean; Crepeau, Taryn; Farajollahi, Ary; Kesavaraju, Banu; Fonseca, Dina; Schoeler, George; Gaugler, Randy; Strickman, Daniel
Aedes albopictus (Skuse) and Ae. japonicus (Theobald) are important container-inhabiting mosquitoes that transmit disease agents, outcompete native species, and continue to expand their range in the United States. Both species deposit eggs in natural and artificial containers and thrive in peridomestic environments. The goal of our study was to examine the types and characteristics of containers that are most productive for these species in the northeastern United States. In total, 306 containers were sampled in urban, suburban, and rural areas of New Jersey. Multiple biotic and abiotic factors were recorded in an attempt to identify variables associated with the productivity of each species. Based on pupal abundance and density of container types, results showed that tires, trash cans, and planter dishes were the most important containers for Ae. albopictus, while planter dishes were the most important containers for Ae. japonicus. Container color (black and gray), material (rubber), and type (tires) were correlated with species presence for Ae. albopictus and Ae. japonicus. These factors may play a role in the selection of oviposition sites by female mosquitoes or in the survival of their progeny. Differences in species composition and abundance were detected between areas classified as urban, suburban, and rural. In urban and suburban areas, Ae. albopictus was more abundant in container habitats than Ae. japonicus; however, Ae. japonicus was more abundant in rural areas, and when water temperatures were below 14 degrees C. Our results suggest many variables can influence the presence of Ae. albopictus and Ae. japonicus in container habitats in northeastern United States.
Full Text Available The presence of Anopheles (Nyssorhynchus dunhami Causey in Colombia (Department of Amazonas is confirmed for the first time through direct comparison of mtDNA cytochrome c oxidase I (COI barcodes and nuclear rDNA second internal transcribed spacer (ITS2 sequences with topotypic specimens of An. dunhami from Tefé, Brazil. An. dunhami was identified through retrospective correlation of DNA sequences following misidentification as Anopheles nuneztovari s.l. using available morphological keys for Colombian mosquitoes. That An. dunhami occurs in Colombia and also possibly throughout the Amazon Basin, is of importance to vector control programs, as this non-vector species is morphologically similar to known malaria vectors including An. nuneztovari, Anopheles oswaldoi and Anopheles trinkae. Species identification of An. dunhami and differentiation from these closely related species are highly robust using either DNA ITS2 sequences or COI DNA barcode. DNA methods are advocated for future differentiation of these often sympatric taxa in South America.
Alemayehu, Eba; Asale, Abebe; Eba, Kasahun; Getahun, Kefelegn; Tushune, Kora; Bryon, Astrid; Morou, Evangelia; Vontas, John; Van Leeuwen, Thomas; Duchateau, Luc; Yewhalaw, Delenasaw
The emergence and spread of insecticide resistance in the major African malaria vectors Anopheles gambiae (s.s.) and An. arabiensis may compromise the current vector control interventions and threatens the global malaria control and elimination efforts. Insecticide resistance was monitored in several study sites in Ethiopia from 2013 to 2015 using papers impregnated with discriminating concentrations of DDT, deltamethrin, bendiocarb, propoxur, malathion, fenitrothion and pirimiphos-methyl, following the WHO insecticide susceptibility test procedure. Mosquitoes sampled from different localities for WHO bioassay were morphologically identified as An. gambiae (s.l.) using standard taxonomic keys. Samples were identified to species using species-specific polymerase chain reaction (PCR) and screened for the presence of target site mutations L1014F, L1014S and N1575Y in the voltage gated sodium channel (VGSC) gene and G119S in the acethylcholinesterase (AChE) gene using allele-specific PCR. Biochemical assays were performed to assess elevated levels of acetylcholinesterases, carboxylcholinesterases, glutathione-S-transferases (GSTs) and cytochrome P450s monooxygenases in wild populations of An. arabiensis, compared to the fully susceptible Sekoru An. arabiensis laboratory strain. Populations of An. arabiensis were resistant to DDT and deltamethrin but were susceptible to fenitrothion in all the study sites. Reduced susceptibility to malathion, pirimiphos-methyl, propoxur and bendiocarb was observed in some of the study sites. Knockdown resistance (kdr L1014F) was detected in all mosquito populations with allele frequency ranging from 42 to 91%. Elevated levels of glutathione-S-transferases (GSTs) were detected in some of the mosquito populations. However, no elevated levels of monooxygenases and esterases were detected in any of the populations assessed. Anopheles arabiensis populations from all surveyed sites in Ethiopia exhibited resistance against DDT and pyrethroids. Moreover, some mosquito populations exhibited resistance to propoxur and possible resistance to bendiocarb. Target site mutation kdr L1014F was detected in all mosquito populations while elevated levels of glutathione-S-transferases (GSTs) was detected in some mosquito populations. The reduced susceptibility of An. arabiensis to propoxur and bendiocarb, which are currently used for indoor residual spraying (IRS) in Ethiopia, calls for continuous resistance monitoring, in order to plan and implement evidence based insecticide resistance management.
Pavela, R.; Vrchotová, Naděžda; Tříska, Jan
Roč. 165, mar (2016), s. 51-57 ISSN 0014-4894 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : botanical larvicide * Furanochromenes * Visnagin * Khellin * Sublethal effect * Mosquito Subject RIV: GC - Agronomy Impact factor: 1.724, year: 2016
Fábio Saito Monteiro de Barros
Full Text Available We performed a longitudinal study of adult survival of Anopheles darlingi, the most important vector in the Amazon, in a malarigenous frontier zone of Brazil. Survival rates were determined from both parous rates and multiparous dissections. Anopheles darlingi human biting rates, daily survival rates and expectation of life where higher in the dry season, as compared to the rainy season, and were correlated with malaria incidence. The biting density of mosquitoes that had survived long enough for completing at least one sporogonic cycle was related with the number of malaria cases by linear regression. Survival rates were the limiting factor explaining longitudinal variations in Plasmodium vivax malaria incidence and the association between adult mosquito survival and malaria was statistically significant by logistic regression (P<0.05. Survival rates were better correlated with malaria incidence than adult mosquito biting density. Mathematical modeling showed that P. falciparum and P. malariae were more vulnerable to changes in mosquito survival rates because of longer sporogonic cycle duration, as compared to P. vivax, which could account for the low prevalence of the former parasites observed in the study area. Population modeling also showed that the observed decreases in human biting rates in the wet season could be entirely explained by decreases in survival rates, suggesting that decreased breeding did not occur in the wet season, at the sites where adult mosquitoes were collected. For the first time in the literature, multivariate methods detected a statistically significant inverse relation (P<0.05 between the number of rainy days per month and daily survival rates, suggesting that rainfall may cause adult mortality.
Oswaldo Paulo Forattini
Full Text Available Based on type examination, Culex (Melanoconion theobaldi (Lutz, 1904 is redescribed. The species Cx. (Mel. chrysonotum Dyar & Knab, 1908, was put back as synonym of theobaldi. Besides, examination of Cx. (Mel. chrysothorax (Newstead & Thomas, 1910 type, leads to retiring as synonym of theobaldi and considered it as "species inquirenda".
Full Text Available Irrigation schemes and dams have posed a great concern on public health systems of several countries, mainly in the tropics. The focus of the present review is to elucidate the different ways how these human interventions may have an effect on population dynamics of anopheline mosquitoes and hence, how local malaria transmission patterns may be changed. We discuss different studies within the three main tropical and sub-tropical regions (namely Africa, Asia and the Pacific and the Americas. Factors such as pre-human impact malaria epidemiological patterns, control measures, demographic movements, human behaviour and local Anopheles bionomics would determine if the implementation of an irrigation scheme or a dam will have negative effects on human health. Some examples of successful implementation of control measures in such settings are presented. The use of Geographic Information System as a powerful tool to assist on the study and control of malaria in these scenarios is also highlighted.
Full Text Available Background: The expansion of herbicide used in aquatic ecosystems as well as in terrestrial if is not properly controlled may produce harmful effects on freshwater fisheries. Residue limits of these agricultural chemicals in tropical fishery waters should be established. The aim of this study was to determine the acute toxicity of butachlor and pertilachlor as potential dangerous herbicides to assess mortality effects of these chemicals to the Mosquito Culex quinquefasciatus. Methods: This study was carried out in Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran at summer 2013. Culex samples were exposed to different concentrations of butachlor and pertilachlor (0-200ppm for butachlor and pertilachlor for 96 h. Results: The low toxicity of LC50s obtained for butachlor (23.81±0.04 and pertilachlor (27.97±0.05 indicate that butachlor and pertilachlor were lowly toxic to Mosquito Cu. quinquefasciatus. Conclusion: Although pretilachlor and butachlor are low toxic but pretilachlor is less toxic in field conditions, these data are useful to potential ecosystem risk assessment.
Loetti, V.; Schweigmann, N.J.; Burroni, N.E., E-mail: firstname.lastname@example.org [Universidad de Buenos Aires (Argentina). Facultad de Ciencias Exactas y Naturales. Grupo de Estudio de Mosquitos
The effect of constant temperatures on the development time from first instar to adult emergence was studied in Culex eduardoi Casal and Garcia reared at 7, 10, 15, 20, 25, 30 or 33 deg C. Data were adjusted to the linear degree-day model and the nonlinear Briere model. According to the linear model, the development time was inversely related to the rearing temperatures between 7 deg C and 25 deg C. Maximum mortality (100%) was recorded at temperatures > 30 deg C. According to the linear model, the development threshold temperature and thermal constant were 5.7 deg C and 188.8 degree days, respectively. The lower and upper threshold temperatures and the optimum temperature for the nonlinear model were -2.3, 30.0 and 28.1 deg C, respectively. (author)
Estep, Alden S; Sanscrainte, Neil D; Waits, Christy M; Louton, Jessica E; Becnel, James J
Puerto Rico (PR) has a long history of vector-borne disease and insecticide-resistant Aedes aegypti (L.). Defining contributing mechanisms behind phenotypic resistance is critical for effective vector control intervention. However, previous studies from PR have each focused on only one mechanism of pyrethroid resistance. This study examines the contribution of P450-mediated enzymatic detoxification and sodium channel target site changes to the overall resistance phenotype of Ae. aegypti collected from San Juan, PR, in 2012. Screening of a panel of toxicants found broad resistance relative to the lab susceptible Orlando (ORL1952) strain. We identified significant resistance to representative Type I, Type II, and nonester pyrethroids, a sodium channel blocker, and a sodium channel blocking inhibitor, all of which interact with the sodium channel. Testing of fipronil, a chloride channel agonist, also showed low but significant levels of resistance. In contrast, the PR and ORL1952 strains were equally susceptible to chlorfenapyr, which has been suggested as an alternative public health insecticide. Molecular characterization of the strain indicated that two common sodium channel mutations were fixed in the population. Topical bioassay with piperonyl butoxide (PBO) indicated cytochrome P450-mediated detoxification accounts for approximately half of the resistance profile. Transcript expression screening of cytochrome P450s and glutathione-S-transferases identified the presence of overexpressed transcripts. This study of Puerto Rican Ae. aegypti with significant contributions from both genetic changes and enzymatic detoxification highlights the necessity of monitoring for resistance but also defining the multiple resistance mechanisms to inform effective mosquito control. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by US Government employees and is in the public domain in the US.
Blosser, Erik M; Lord, Cynthia C; Stenn, Tanise; Acevedo, Carolina; Hassan, Hassan K; Reeves, Lawrence E; Unnasch, Thomas R; Burkett-Cadena, Nathan D
Field studies were carried out in four Florida counties to investigate winter and spring ecology of host use by Culiseta melanura (Coquillet), the primary vector of eastern equine encephalomyelitis virus (EEEV) in North America. Bloodmeal analysis by PCR was used to identify 233 host bloodmeals, which mainly originated from birds (78.5%) and reptiles (17.2%), primarily Anolis spp. lizards. Across counties, the percentage of bloodmeals from reptiles (7-37% depending upon county) increased with increasing day length and temperature in the spring. Multiple logistic regression revealed that differences in reptile host use across collection sites were largely explained by differences in average day length and temperature on the day of collection, and is probably owing to environment-driven behavioral patterns of ectothermic animals. Although past studies have demonstrated reptile biting by epizootic vectors of EEEV, including Culex (Melanoconion) spp., this is the first study to demonstrate widespread and common feeding upon ectothermic hosts by Cs. melanura. This work suggests that reptiles, particularly anole lizards, play a role in the ecology of EEEV in Florida either as amplifying hosts or as noncompetent hosts which dilute vector feedings thereby suppressing transmission. Detailed laboratory studies investigating impacts of environmental variables (temperature and photoperiod) on EEEV competence of anoles are needed to assess whether these animals support virus amplification. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
Oswaldo Paulo Forattini
Full Text Available New research concerning Anopheles bellator in the southeast of the State of São Paulo, Brazil, are reported. Adult females of this mosquito showed remarkable endophily and endophagy which was even greater than An. cruzii. The epidemiological role of this anopheline as a malaria vector is discussed.
2 pl. 1966. Mosquitos de Venezuela. Vol. 1. Galindo, P. 1973. Experiencias epidemiolo- Ministerio de Sanidad y Asistencia Social, gicas en el Proyecto ...Heinemann, S.J. and J.N. Belkin. 1977b. Col- Facultad de Ciencias Biologia. Universidad lection records of the project "Mosquitoes Nacional Autonoma de
guinea pig blood and a 10% sucrose solution to develop ovaries and lay eggs . After 24 h, those females in good condition and well-fed were separated for...each individual labeled to maintain the as- sociation between each female and the corresponding egg batch. Eggs from each female were kept separate...spot/length of the distal sector dark spot (DS-III2/Ta-III2, HP/PHD, SCP/DSD) approximately 5% of the adult females were misidentified as a species
Porretta, Daniele; Mastrantonio, Valentina; Crasta, Graziano; Bellini, Romeo; Comandatore, Francesco; Rossi, Paolo; Favia, Guido; Bandi, Claudio; Urbanelli, Sandra
Cannibalism has been observed in a wide range of animal taxa and its importance in persistence and stability of populations has been documented. In anopheline malaria vectors the inter-instar cannibalism between fourth- and first-instar larvae (L4-L1) has been shown in several species, while intra-instar cannibalism remains poorly investigated. In this study we tested the occurrence of intra-instar cannibalism within larvae of second-, third- and fourth-instar (L2, L3 and L4) of Anopheles gambiae (s.s.) and An. stephensi. Experiments were set up under laboratory conditions and the effects of larval density, duration of the contact period among larvae and the presence of an older larva (i.e. a potential cannibal of bigger size) on cannibalism rate were analysed. Cannibalism was assessed by computing the number of missing larvae after 24 and 48 h from the beginning of the experiments and further documented by records with a GoPro videocamera. Intra-instar cannibalism was observed in all larval instars of both species with higher frequency in An. gambiae (s.s.) than in An. stephensi. In both species the total number of cannibalistic events increased from 0-24 to 0-48 h. The density affected the cannibalism rate, but its effect was related to the larval instar and to the presence of older larvae. Interestingly, the lower cannibalism rate between L4 larvae was observed at the highest density and the cannibalism rate between L3 larvae decreased when one L4 was added. The present study provides experimental evidence of intra-instar cannibalism in the malaria vectors An. gambiae (s.s.) and An. stephensi and highlights the possible occurrence of complex interactions between all larval instars potentially present in the breeding sites. We hypothesize that the high density and the presence of a potential cannibal of bigger size could affect the readiness to attack conspecifics, resulting into low risk larval behavior and lower cannibalism rate. The understanding of cannibalistic behavior and the factors affecting it is of utmost importance for malaria vectors, as nutrition during larval development can strongly affect the fitness of adult female mosquitoes and ultimately their vector ability.
Full Text Available Abstract Background Cannibalism has been observed in a wide range of animal taxa and its importance in persistence and stability of populations has been documented. In anopheline malaria vectors the inter-instar cannibalism between fourth- and first-instar larvae (L4-L1 has been shown in several species, while intra-instar cannibalism remains poorly investigated. In this study we tested the occurrence of intra-instar cannibalism within larvae of second-, third- and fourth-instar (L2, L3 and L4 of Anopheles gambiae (s.s. and An. stephensi. Experiments were set up under laboratory conditions and the effects of larval density, duration of the contact period among larvae and the presence of an older larva (i.e. a potential cannibal of bigger size on cannibalism rate were analysed. Cannibalism was assessed by computing the number of missing larvae after 24 and 48 h from the beginning of the experiments and further documented by records with a GoPro videocamera. Results Intra-instar cannibalism was observed in all larval instars of both species with higher frequency in An. gambiae (s.s. than in An. stephensi. In both species the total number of cannibalistic events increased from 0–24 to 0–48 h. The density affected the cannibalism rate, but its effect was related to the larval instar and to the presence of older larvae. Interestingly, the lower cannibalism rate between L4 larvae was observed at the highest density and the cannibalism rate between L3 larvae decreased when one L4 was added. Conclusions The present study provides experimental evidence of intra-instar cannibalism in the malaria vectors An. gambiae (s.s. and An. stephensi and highlights the possible occurrence of complex interactions between all larval instars potentially present in the breeding sites. We hypothesize that the high density and the presence of a potential cannibal of bigger size could affect the readiness to attack conspecifics, resulting into low risk larval behavior and lower cannibalism rate. The understanding of cannibalistic behavior and the factors affecting it is of utmost importance for malaria vectors, as nutrition during larval development can strongly affect the fitness of adult female mosquitoes and ultimately their vector ability.
Full Text Available Objective: To evaluate immature mosquitocidal properties of Xanthium strumarium plant extracts against Culex mosquitoes at Entomology Laboratory, Maraki Campus, University of Gondar. Methods: The immature mosquitocidal activity of plant extracts was tested by following World Health Organization recommended protocol. Acetone, methanol and water extracts were prepared at 50, 100, 150, 200 and 250 mg/L concentrations and tested against third and fourth instar larvae and pupae of Culex mosquitoes. The mortality rate of immature mosquitoes was recorded after 24, 48 and 72 h exposure period continuously. Results: Third instar larvae after 24 h exposure period, maximum mortality of 77.80% was recorded at 250 mg/L concentration of acetone extract. After 48 h and 72 h exposure period, maximum mortality of 88.90% was recorded in acetone extract in all the tested concentration. The maximum mortality of fourth instar larvae was 88.90% in acetone extract at 200 and 250 mg/L concentrations. Pupal mortality was also greater in acetone extract. The percentage of mortality in all the stage of mosquitoes was higher in acetone extract followed by methanol and water extract. Conclusions: The percentage of mortality is associated with concentration of the extracts tested and exposure period. This laboratory study confirmed immature mosquitocidal activity of Xanthium strumarium leaf extracts against Culex mosquitoes. The aqueous leaf extract can be used by applying on small man-made breeding places to prevent adult emergence.
Background Anopheles sinensis is the major malaria vector in China and Southeast Asia. Vector control is one of the most effective measures to prevent malaria transmission. However, there is little transcriptome information available for the malaria vector. To better understand the biological basis of malaria transmission and to develop novel and effective means of vector control, there is a need to build a transcriptome dataset for functional genomics analysis by large-scale RNA sequencing (RNA-seq). Methods To provide a more comprehensive and complete transcriptome of An. sinensis, eggs, larvae, pupae, male adults and female adults RNA were pooled together for cDNA preparation, sequenced using the Illumina paired-end sequencing technology and assembled into unigenes. These unigenes were then analyzed in their genome mapping, functional annotation, homology, codon usage bias and simple sequence repeats (SSRs). Results Approximately 51.6 million clean reads were obtained, trimmed, and assembled into 38,504 unigenes with an average length of 571 bp, an N50 of 711 bp, and an average GC content 51.26%. Among them, 98.4% of unigenes could be mapped onto the reference genome, and 69% of unigenes could be annotated with known biological functions. Homology analysis identified certain numbers of An. sinensis unigenes that showed homology or being putative 1:1 orthologues with genomes of other Dipteran species. Codon usage bias was analyzed and 1,904 SSRs were detected, which will provide effective molecular markers for the population genetics of this species. Conclusions Our data and analysis provide the most comprehensive transcriptomic resource and characteristics currently available for An. sinensis, and will facilitate genetic, genomic studies, and further vector control of An. sinensis. PMID:25000941
Full Text Available Objective: To examine Beauveria bassiana (B. bassiana fungus bioassay against the larval stages of Anopheles stephensi in Iran. Methods: The fungal suspension by the concentrations of 1伊1 09, 5伊1 08, 1 08, 5伊1 07 and 1伊 107 conidia per milliliter have been prepared in different volumes (2, 4 and 6 mL and each concentration were added to containers containing 25 Anopheles larva instars 1 and 2. The mortality of the dead larvae with abnormal symptoms was recorded as a result of the fungal infection after 24, 48 and 72 h. Results: Comparison between the mean mortality rate of Anopheles stephensi larva at different concentrations of B. bassiana strain Iran 429C at 2, 4 and 6 mL showed that there was no significant relation of the mean mortality rate of larvae at concentrations of 1伊109 and 5伊108, and after 48 h resulted in 100% mortality rate of the larvae populations. In addition, there is no significant differences in the amounts of lethal times (LT (LT50 and LT90 as LT90 values calculated at a concentration of 5伊108 and in volumes 2, 4 and 6 mL were 1.46, 1.36 and 1.08 d, respectively. Conclusions: B. bassiana strain Iran 429C in 2 mL of 5伊108 concentration or the concentration of a 1伊109 mL per 100 mL of water is recommended as the optimal concentration for the control of Anopheles larvae. The development of suitable formulations of entomopathogenic fungi may be a promising prospect in the mosquito control programs.
Vivekanandhan, Perumal; Kavitha, Thangaraj; Karthi, Sengodan; Senthil-Nathan, Sengottayan; Shivakumar, Muthugoundar Subramanian
Microbial-based pest control is an attractive alternative to chemical insecticides. The present study sought to evaluate the toxicity of the entomopathogenic fungus Beauveria bassiana -28 ethyl acetate extracts on different larval stages and pupae of Culex quinquefasciatus mosquitoes. B. bassiana -28 ethyl acetate mycelial extracts produced mosquitocidal activity against larvae and pupae which was comparable to that of the commercial insecticide B. bassiana -22 extract. The LC 50 (lethal concentration that kills 50% of the exposed larvae) values of B. bassiana -28 extracts for 1st to 4th instar larvae and pupae were 11.538, 6.953, 5.841, 3.581 and 9.041 mg/L respectively. Our results show that B. bassiana -28 ethyl acetate mycelial extract has strong insecticidal activity against larval and pupal stages of Cx. quinquefasciatus . Fourier transform infrared spectrum study of B. bassiana -28 extract shows peaks at 3226.91; 2927.94; 1593.13; 1404.18; 1224.18; 1247.94; 1078.21; 1018.41; 229.69; and 871.82 cm -1 . Major spectral peaks were observed at 3226.91 cm -1, assigned to N-H stretching, 2927.94 cm -1 assigned to C-H bonding and 1595.13 cm -1 assigned to C-O stretching. Gas Chromatography-Mass Spectrometry studies of B. bassiana -28 ethyl acetate crude extract showed presence of six major compounds viz. N -hexadecanoic acids (13.6040%); Z,Z -9,12 octadecadienic acid (33.74%); 9-eicosyne (10.832%); heptacosane (5.148%); tetrateracontane (5.801%); and 7 hexyleicosane (5.723%). Histology of mosquito midgut tissue shows tissue lysis as a result of B.bassiana -28 extract exposure. The study shows that bioactive molecules obtained from B. bassiana -28 mycelial extract has insecticidal properties and can be used as alternative for mosquito control.
Full Text Available Microbial-based pest control is an attractive alternative to chemical insecticides. The present study sought to evaluate the toxicity of the entomopathogenic fungus Beauveria bassiana-28 ethyl acetate extracts on different larval stages and pupae of Culex quinquefasciatus mosquitoes. B. bassiana-28 ethyl acetate mycelial extracts produced mosquitocidal activity against larvae and pupae which was comparable to that of the commercial insecticide B. bassiana-22 extract. The LC50 (lethal concentration that kills 50% of the exposed larvae values of B. bassiana-28 extracts for 1st to 4th instar larvae and pupae were 11.538, 6.953, 5.841, 3.581 and 9.041 mg/L respectively. Our results show that B. bassiana-28 ethyl acetate mycelial extract has strong insecticidal activity against larval and pupal stages of Cx. quinquefasciatus. Fourier transform infrared spectrum study of B. bassiana-28 extract shows peaks at 3226.91; 2927.94; 1593.13; 1404.18; 1224.18; 1247.94; 1078.21; 1018.41; 229.69; and 871.82 cm−1. Major spectral peaks were observed at 3226.91 cm−1, assigned to N–H stretching, 2927.94 cm−1 assigned to C–H bonding and 1595.13 cm−1 assigned to C–O stretching. Gas Chromatography-Mass Spectrometry studies of B. bassiana-28 ethyl acetate crude extract showed presence of six major compounds viz. N-hexadecanoic acids (13.6040%; Z,Z-9,12 octadecadienic acid (33.74%; 9-eicosyne (10.832%; heptacosane (5.148%; tetrateracontane (5.801%; and 7 hexyleicosane (5.723%. Histology of mosquito midgut tissue shows tissue lysis as a result of B.bassiana-28 extract exposure. The study shows that bioactive molecules obtained from B. bassiana-28 mycelial extract has insecticidal properties and can be used as alternative for mosquito control.
Cianci, D.; Hartemink, N.; Zeimes, C.B.; Vanwambeke, S.O.; Ienco, A.; Caputo, B.
Over the past decades, the Asian tiger mosquito (Aedes albopictus (Skuse, 1895)) has emerged in many countries, and it has colonized new environments, including urban areas. The species is a nuisance and a potential vector of several human pathogens, and a better understanding of the habitat
.... Experiments using Venezuelan equine encephalitis viral replicon particles, which express the green fluorescent protein gene in cells, indicate the operation of tissue conduits, possibly involving...
Andrés G. Rueda
Full Text Available Aedes aegypti is the principal vector of arboviral pathogens that may cause diseases as dengue fever, chikungunya and zika. The harmful environmental effects of commercial pesticides coalesced with the development of insecticide-resistant populations encourage the discovery and generation of new alternative products as a tool to reduce the incidence of vector-borne diseases. In this work, through the classic three component Strecker reaction of commercial benzaldehydes, cyclic secondary amines and KCN, a new series of nine α-amino nitriles, girgensohnine analogs, has been synthetized and screened for larvicide and adulticide properties against A. aegypti, one of the dominant vectors of dengue, chikungunya and zika in tropical and subtropical areas all over the world. Molecules 3 and 4 were identified as potential larvicidal agents with LC50 values of 50.55 and 69.59 ppm, respectively. Molecule 3 showed 100% of mortality after 2 h of treatment when a concentration of 30 ppm in adulticidal assays was evaluated. Additionally, in order to elucidate the mode of action of these molecules, their acetylcholinesterase (AChE inhibitory properties were evaluated using the Ellman assay. It was found that the molecules possess a weak AChE inhibitory activity with IC50 values between 148.80 and 259.40 μM, indicating that AChE could not be a principal target for insecticide activity. Keywords: Arthropod-borne diseases, Girgensohnine analogs, Strecker reaction, Insecticidal activity, Vector control
Full Text Available The search for new insecticides to control dengue fever, chikungunya, and Zika vectors has gained relevance in the past decades. The aim of the present study was to evaluate the larvicidal action of essential oils (EOs from Thymus vulgaris, Salvia officinalis, Lippia origanoides, Eucalyptus globulus, Cymbopogon nardus, Cymbopogon martinii, Lippia alba, Pelargonium graveolens, Turnera diffusa, and Swinglea glutinosa on Aedes (Stegomyia aegypti. The EOs were extracted by microwave-assisted hydrodistillation and characterized by gas chromatography/mass spectrometry (GC/MS. The chemical components of the EOs were identified by linear retention indices and mass spectra. Lethal concentrations (LC50 and LC95 were determined by probit analysis using larvae of Ae. aegypti between the third and the fourth instars. All EOs achieved larvicidal activity at LC50 values lower than 115 mg/L. The lowest LC50 value (45.73 mg/L corresponded to T. vulgaris EO, whereas C. martinii EO showed the highest LC50 (LC50 = 114.65 mg/L. Some EO mixtures showed lower LC50 than oils used individually, such as the mixtures of L. origanoides + S. glutinosa (LC50 = 38.40 mg/L, T. diffusa + S. glutinosa (LC50 = 63.71 mg/L, and L. alba + S. glutinosa (LC50 = 48.87 mg/L. The main compounds of the EOs with highest larvicidal activity were thymol (42% and p-cymene (26.4%. Keywords: Essential oil, Larvicidal activity, Mosquito control
Alvarez, Leslie C; Ponce, Gustavo; Oviedo, Milagros; Lopez, Beatriz; Flores, Adriana E
Temephos is an insecticide widely used in Venezuela to control the proliferation of the larvae of Aedes aegypti (L.), the principal vector of dengue virus. The aim of this study was to identify the susceptibility to temephos of Ae. aegypti in four locations in western Venezuela: Lara, Tres Esquinas, Ureña and Pampanito. Larval bioassays were conducted on samples collected in 2008 and 2010, and the levels of α- and β-esterases, mixed-function oxidases, glutathione-S-transferase and insensitive acethyl cholinesterase were determined. Larval populations from western Venezuela obtained during 2008 and 2010 were found to be susceptible to temephos, with low resistance ratios and without overexpression of enzymes. The low RR values reveal the effectiveness of temephos in controlling the larval populations of Ae. aegypti. Control strategies must be vigorously monitored to maintain the susceptibility to temephos of these populations of Ae. aegypti. © 2013 Society of Chemical Industry.
Full Text Available Se describen los síntomas en larvas de A. aquasalis infectadas naturalmente con un microsporidio parasítico, y la ultraestructura de las esporas del mismo. Las larvas fueron criadas bajo condiciones de laboratorio en concentraciones de salinidad de 10 g/l y 20 g/l, registrándose diariamente la mortalidad y la fecha del cambio de estadío de las mismas. Las larvas infectadas fueron procesadas por rnicroscopía electrónica de transmisión usando métodos convencionales con pH 7.2 y 260 mOsm/I. El incremento de la infección por los microsporidios estuvo correlacionado positivamente con un aumento en la duración promedio del cuarto estadío de 2.88 a 6.33 días en 10 g/l de sal y de 2.47 a 6.14 días en 20 g/l. La mortalidad de las larvas también aumentó en aproximadamente 50% durante este estadío a ambas concentraciones de salinidad. No se observaron estas alteraciones en los otros estadíos. Las esporas maduras de los microsporidios fueron encontradas en el intestino de las larvas. Estas esporas mostraron forma de barril y dimensiones de 2.6 x 2.4 µm aproximadamente. La reducción en la supervivencia de las larvas de A. aquasalis infectadas con los microsporidios, y el aumento del tiempo de su desarrollo sugiere que este parásito podría ser un posible controlador biológico de esta plaga. El microsporidio descrito presenta características similares a las del género Parathelohania. Se sugiere que el microsporidio encontrado en las larvas de A. aquasalis es una especie nueva y se propone nombrarla Parathelohania aquasalensis. Este trabajo representa el primer reporte de un microsporidio encontrado en un díptero en Venezuela.The symptoms of Anopheles aquasalis larvae naturally infected by a microsporidium, and the ultrastructure of the infecting spores is describes. The larvae were maintained under laboratory conditions in salt concentrations of 10 g/l and 20 g/l of water. Daily recordings of the mortality of the larvae were made and the dates of change of instar were noted. Infected larvas were processed for transmission electronic microscopy using conventional methods at pH 7.2 and 260 mOsm/l. The infection by the microsporidia was positively correlated with an increase in the mean duration of the fourth instar of 2.88 to 6.33 days in 10 g/l of salt and of 2.47 to 6.14 days in 20 g/l of salt. Larval mortality also increased by approximately 50% during this instar in both salt concentrations. Development time and survival were not affected during the other immature stages. The mature spores found in the intestines of infected larvae were barrel shaped and measured approximately 2.6 x 2.4 mm. The exospore has a collar shaped prolongation at the posterior end of the spore. The spores are uninuclear with a posterior vacuole. The polar filament is anisofilar with nine rings, five with a diameter of 58 nm each and four with a diameter of 23 nm each. The polarplast is lamellate, and more tightly packed in the apical region. The reduction of the survival of A. aquasalis larvae infected with the microsporidia, and the increase in the development time suggest that this parasite might have a potential as a biological control of this pest. The microsporidium describes here has similar characteristics to that of the genus Parathelohania. I suggest that the rnicrosporidium found in A. aquasalis represents a new species and I propose the name Parathelohania aquasalensis. This is the first report of a microsporidium from a dipteran in Venezuela.
McPhatter, Lee P; Su, Tianyun; Williams, Greg; Cheng, Min-Lee; Dhillon, Major; Gerry, Alec C
Knowledge of the blood-feeding patterns exhibited by arthropod vectors is essential for understanding the complex dynamics of vector-borne disease transmission. Some species of mosquitoes belonging to the genus Culex have been implicated as having major roles in the transmission of arboviruses such as West Nile virus, Saint Louis encephalitis virus, and Western equine encephalitis virus. Although the host-feeding patterns for many of these Culex species are well studied, the host-feeding patterns of Culex stigmatosoma Dyar are relatively poorly studied, even though this species is suspected to be an important maintenance vector for West Nile virus and other arboviruses. In the current study, bloodmeals from 976 blood-engorged Cx. stigmatosoma, collected from 30 sites in southern California from 2009-2012, were processed for vertebrate host identification by nucleotide sequencing following polymerase chain reaction to amplify portions of the cytochrome oxidase I and cytochrome b genes of vertebrate animals. Vertebrate DNA was amplified, sequenced, and identified from a total of 647 Cx. stigmatosoma bloodmeals, revealing that 98.6% of bloodmeals were from birds, 1.2% from three mammal species, and a single bloodmeal was from a reptile species. In total, 40 different host species were identified. The greatest number of bloodmeals identified was from domestic chicken (Gallus gallus domesticus L.) (38% of bloodmeals), house sparrow (Passer domesticus L.) (23%), house finch (Haemorhous mexicanus Müller) (17%), American crow (Corvus brachyrhynchos L.) (4%), and mourning dove (Zenaida macroura L.) (3%). However, chicken bloodmeals were identified almost entirely from a single site where mosquito collection devices were placed in the near vicinity of confined domestic chickens. The strongly ornithophilic feeding behavior shown in this study for Cx. stigmatosoma supports the hypothesis that this mosquito species may be an important maintenance (or endemic) vector for arboviruses that circulate among susceptible birds. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: firstname.lastname@example.org.
Kamgang, Basile; Nchoutpouen, Elysée; Simard, Frédéric; Paupy, Christophe
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 ...
Jackson, Bryan T; Brewster, Carlyle C; Paulson, Sally L
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.
Farjana, Thahsin; Tuno, Nobuko
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.
Chareonviriyaphap, Theeraphap; Prabaripai, Atchariya; Bangs, Michael J; Aum-Aung, Boonserm
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.
Hall-Mendelin, Sonja; Jansen, Cassie C; Cheah, Wai Yuen; Montgomery, Brian L; Hall, Roy A; Ritchie, Scott A; Van den Hurk, Andrew F
Japanese encephalitis virus (JEV) transmission in northern Australia has, in the past, been facilitated by Culex annulirostris Skuse feeding on domestic pigs, the primary amplifying hosts of the virus. To further characterize mosquito feeding behavior in northern Australia, 1,128 bloodmeals from Cx. annulirostris were analyzed using a double-antibody enzyme-linked immunosorbent assay. Overall, Cx. annulirostris obtained > 94% of blood meals from mammals, comprising marsupials (37%), pigs (20%), dogs (16%), and cows (11%), although the proportion feeding on each of these host types varied between study locations. Where JEV activity was detected, feeding rates on pigs were relatively high. At the location that yielded the first Australian mainland isolate of JEV from mosquitoes, feral pigs (in the absence of domestic pigs) accounted for 82% of bloodmeals identified, representing the first occasion that feeding on feral pigs has been associated with JEV transmission in Australia. Interestingly, blood meals identified, or infected mosquitoes immigrating from areas where domestic pigs are housed, may have contributed to transmission at this location. Because Cx. annulirostris is both an opportunistic feeder and the primary JEV vector in the region, environmental characteristics and host presence can determine JEV transmission dynamics in northern Australia.
Finlayson, Catherine; Saingamsook, Jassada; Somboon, Pradya
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.
Su, T; Mulla, M S
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.
Alencar, Jeronimo; Mello, Cecília Ferreira de; Gil-Santana, Hélcio R; Giupponi, Alessandro Ponce de Leão; Araújo, Andressa Nunes; Lorosa, Elias Seixas; Guimarães, Anthony Érico; Silva, Júlia Dos Santos
The stomach contents of culicids from the Atlantic Forest in Rio de Janeiro state, Brazil, were analyzed using the precipitin technique to evaluate the feeding patterns of the species. Sampling was performed from February 2012 to December 2013, using CO2-baited Centers for Disease Control and Prevention traps to catch mosquitoes from 15 00 to 07 00 hours. The following antisera were used: bird, rodent, opossum, human, horse, capybara, lizard, and frog. Of the 325 adult bloodfed females caught and analyzed, 273 (84.0%) reacted in the precipitin test. The percentage of specimens with a positive reaction to a single antiserum included bird (39.2%), rodent (22.5%), opossum (13.2%), capybara (6.6%), horse (5.7%), frog (6.2%), human (4.0%), and lizard (2.6%). The specimens that reacted positively against more than one blood source (46) most frequently presented the following combinations: bird + rodent and bird + frog (17.4%), followed by bird + human (13.0%). The predominance of positive results for birds suggested that the avian-rich environment might have influenced the feeding behavior of the culicids. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
Kent, Rebekah; Juliusson, Lara; Weissmann, Michael; Evans, Sara; Komar, Nicholas
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.
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.
Godoy, Raquel S M; Fernandes, Kenner M; Martins, Gustavo F
In most mosquito species, the females require a blood-feeding for complete egg development. However, in Toxorhynchites mosquitoes, the eggs develop without blood-feeding, and both females and males exclusively feed on sugary diets. The midgut is a well-understood organ in blood-feeding mosquitoes, but little is known about it in non-blood-feeding ones. In the present study, the detailed morphology of the midgut of Toxorhynchites theobaldi were investigated using histochemical and ultrastructural methods. The midgut of female and male T. theobaldi adults consists of a long, slender anterior midgut (AMG), and a short, dilated posterior midgut (PMG). The AMG is subdivided into AMG1 (short, with folds) and AMG2 (long, without folds). Nerve branches and enteroendocrine cells are present in AMG and PMG, respectively. Compared with the PMG of blood-feeding female mosquitoes, the PMG of T. theobaldi is smaller; however, in both mosquitoes, PMG seems be the main region of food digestion and absorption, and protein secretion. The epithelial folds present in the AMG of T. theobaldi have not been reported in other mosquitoes; however, the midgut muscle organization and endocrine control of the digestion process are conserved in both T. theobaldi and blood-feeding mosquitoes.
Rotraut A. G. B. Cônsoli
Full Text Available Observations were made on 100 female Aedes fluviatilis (Lutz maintained individually from the first blood meal onwards and allowed one blood meal during each oviposition cycle, 5% dextrose solution been supplied throughout life. The average length of live was 49.9 ± 17.8 days; the logarithm of the mortality rate increased proportionately to physiological age. The insects took an average of 7.3 ± 3.2 blood meals and produced a mean of 7.9 ± 3.7 clutches of eggs. There was a progressive decrease, proportional to advancing physiological age, in the mean numbers of eggs laid in successive oviposition cycles, in the intervals between blood feeding oviposition, and in the numbers of larvae that hatched. Delayed oviposition, transient sterility and a total loss of fertility were also recorded.De 100 fêmeas de Aedese fluviatilis (Lutz, 1904 individualmente observadas foram obtidos 45.475 ovos em um total de 790 posturas. As médias de desovas produzidas e de repastos sangüíneos ingeridos por fêmea, foram respectivamente 7,9 ± 3,7 e 7,3 ± 3,2 e a longevidade média foi de 49,9 ± 17,8 dias. Em análise de regressão linear, foi observado um progressivo decréscimo das médias de ovos por postura, larvas eclodidas e número de dias entre repasto sangüíneo e postura, proporcional ao aumento da idade fisiológica. Foram ainda observadas ocorrências de ingestão de sangue durante o desenvolvimento dos ovos, recusa de alimentação sangüínea entre desovas sucessivas, retenção espontânea de ovos por períodos apreciáveis, esterilidade transitória e esgotamento de fecundidade.
Kamgang, Basile; Nchoutpouen, Elysée; Simard, Frédéric; Paupy, Christophe
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.
Godoy, Raquel S. M.; Fernandes, Kenner M.; Martins, Gustavo F.
In most mosquito species, the females require a blood-feeding for complete egg development. However, in Toxorhynchites mosquitoes, the eggs develop without blood-feeding, and both females and males exclusively feed on sugary diets. The midgut is a well-understood organ in blood-feeding mosquitoes, but little is known about it in non-blood-feeding ones. In the present study, the detailed morphology of the midgut of Toxorhynchites theobaldi were investigated using histochemical and ultrastructu...
Damiens, D; Soliban, S M; Balestrino, F; Alsir, R; Vreysen, M J B; Gilles, J R L
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.
Kipyab Pamela C
Full Text Available Abstract Background Anopheles merus, a sibling species of the Anopheles gambiae complex occurs along the East African coast but its biology and role in malaria transmission in this region is poorly understood. We evaluated the blood feeding pattern and the role of this species in malaria transmission in Malindi district, Coastal Kenya. Methods Adult mosquitoes were collected indoors by CDC light traps and Pyrethrum Spray Catch and outdoors by CDC light traps. Anopheles females were identified to species by morphological characteristics and sibling species of An. gambiae complex distinguished by rDNA polymerase chain reaction (PCR. Screening for host blood meal sources and presence or absence of Plasmodium falciparum circumsporozoite proteins was achieved by Enzyme Linked Immunosorbent Assays (ELISA. Results Anopheles merus comprised 77.8% of the 387 Anopheles gambiae s.l adults that were collected. Other sibling species of Anopheles gambiae s.l identified in the study site included An. arabiensis(3.6%, and An. gambiae s.s. (8%. The human blood index for An. merus was 0.12, while the sporozoite rate was 0.3%. Conclusion These findings suggest that An. merus can play a minor role in malaria transmission along the Kenyan Coast and should be a target for vector control which in turn could be applied in designing and implementing mosquito control programmes targeting marsh-breeding mosquitoes; with the ultimate goal being to reduce the transmission of malaria associated with these vectors.
dos Santos Silva, Júlia; Alencar, Jeronimo; Costa, Janira Martins; Seixas-Lorosa, Elias; Guimarães, Anthony Érico
Feeding patterns of mosquitoes in six Brazilian environmental preservation areas were analyzed by the precipitin technique. The mosquito populations were captured using Shannon traps during different time periods. Bird, cow, dog, horse, opossum, human, and rodent antisera diagnostic tests were employed and results were analyzed by calculating the Sørensen similarity index and using the null-model test. Of the 647 analyzed specimens, 443 reacted to the utilized antisera, of which 331 reacted to one blood source, with the most frequent being birds (49.4%); and 112 specimens reacted to two blood sources, with the most frequent combination from birds + rodents (14.3%). The feed profiles demonstrated that Anopheles albitarsis, An. evansae, Aedes fulvus, Psorophora albigenu, Ps. albipes, Ps. ferox, and Mansonia titillans fed predominantly on birds. The similarity index showed that in some localities An. cruzii, Chagasia fajardi, Ae. scapularis, Ae. serratus, Haemagogus leucocelaenus, Ps. albigenu, and Ps. ferox presented similar dietary habits. The null-models test indicated that species from SMSP, INP, CGNP, and THP demonstrated an aggregate pattern, while species from SONP and SBNP showed a random pattern. The mosquitoes fed predominantly on birds, but from an epidemiological standpoint, the eclectic feeding habits were found to be constant among the mosquitoes analyzed. © 2012 The Society for Vector Ecology.
Philip Samuel, P; Arunachalam, N; Hiriyan, J; Tyagi, B K
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.
Jonny E. Duque L.
Full Text Available Presentamos la construcción y la simulación de un modelo matemático, del tipo SIRS (SusceptibleInfeccioso Removido-Susceptible. Se utilizaron cuatro ecuaciones diferenciales para mostrar los parámetros más relevantes que deben ser seguidos en lucha contra vectores del dengue: θ (tasa de control cultural y ϕ (tasa de protección de los criaderos con la aplicación de tratamiento biológico o químico por un tiempo determinado, dentro del control de criaderos que influencian directamente el número de mosquitos que está relacionado con los aspectos ambientales representados por la función Sen2. Intengrando el control cultural y el tratamiento convencional, se puede mantener el número de criaderos en niveles bajos y con ello, la población de mosquitos. Debe utilizarse un control integrado para disminuir el número de criaderos de mosquitos y así reducir la cantidad de los mismos
Raúl Ernesto Campos
Full Text Available Egg hatching of winter-collected Ochlerotatus albifasciatus was studied for six months. Batches of eggs were divided into two groups, one of them was stored in the laboratory at 23°C and 12:12 photoperiod, and the other in the field under dead leaves. Every month, from July to December, eggs from the two groups were flooded under both laboratory and field conditions. Unhatched eggs were returned to the original condition and flooded two more times separated by ten-day intervals. Results show that egg diapause is expressed in different intensities, not only on eggs exposed to different conditions but also in those exposed to the same condition, even when they were laid by the same female. Successive inundations yielded incomplete hatches of eggs, and favored the hatching response in the next flooding. Low environmental temperatures before and during the flooding depressed hatching response. This shows that eggs need a warm period before flooding as well as warm temperatures during flooding, to hatch. As drought period was longer hatching response increased, but this was also accompanied by warmer environmental conditions. The experiment performed in laboratory did not show that increment. Field studies showed that a layer of dead leaves protected eggs from extreme temperatures.
Braima, Kamil A; Muslimin, M; M Ghazali, Amir-Ridhwan; Wan-Nor, F; Wilson, J J; Jeffery, J; Abdul-Aziz, N M
Mosquitoes are vectors of various human diseases in the tropics including yellow fever, dengue, malaria and West Nile virus. Mosquitoes can act as vectors between wildlife and humans, which is particularly important for diseases where wild animals serve as reservoirs of parasites in the absence of human infections. Research has mainly focused on the medical impacts of Anopheles, Aedes, Mansonia and Culex, however, very little attention has been directed towards other mosquito genera, especially those which act as vectors of diseases of wildlife. We have observed adults of Mimomyia (Etorleptiomyia) luzonensis (Ludlow, 1905) feeding on a toad, Ingerophrynus parvus, near an oil palm plantation settlement in Setia Alam, Selangor state, Peninsular Malaysia. Mimomyia is known to feed on reptiles and amphibians, and is a documented vector of several arboviruses, including West Nile virus. The observation of Mimomyia feeding on a common toad near a human settlement highlights a need to understand the relationships between mosquitoes, toads and humans from an ecological perspective. We report on-site observations of the feeding habit of Mimomyia; the first records from Malaysia. Copyright © 2017 Elsevier B.V. All rights reserved.
Mathew, G; Rai, K S
An ultrastructural study of mosquito ovarioles reveals that both the vitelline membrane and the endochorion are secreted by the follicular epithelium. The presecretory phase is characterized by the hypertrophy of endoplasmic reticulum and Golgi complex in the follicle cells. Synthesis of vitelline membrane precursors begins immediately after yolk protein uptake by micropinocytosis. Secretory droplets are budded off Golgi cisternae and released into the follicle cell--oocyte interface by exocytosis. The vitelline membrane first appears as dense plaques which eventually fuse to form a single homogeneous layer. Two types of secretory material are identified in the follicle cells prior to the formation of the endochorion. Golgi cisternae bud off small droplets similar in size and appearance to the precursors of the vitelline membrane. These migrate to the apical surface and accumulate between surface folds in the plasma membrane. The second type is a fibrous material formed in endoplasmic reticulum. When fully secreted, the endochorion is a 2-layered structure. The lower layer is comprised of pillar-like structures alternating with fibrous mesh-like areas. The pillars are formed by the coalescence of droplets released from Golgi, while the mesh-like areas presumably arise from the fibrous material. The outer layer is also fibrous. The follicle cells degenerate once the endochorion is laid down. endochorion is laid down.
Koutsaviti, Katerina; Giatropoulos, Athanassios; Pitarokili, Danae; Papachristos, Dimitrios; Michaelakis, Antonios; Tzakou, Olga
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.
Gaye, Alioune; Faye, Oumar; Diagne, Cheikh T; Faye, Ousmane; Diallo, Diawo; Weaver, Scott C; Sall, Amadou A; Diallo, Mawlouth
To investigate the potential for domestic and wild populations of Aedes aegypti from Dakar and Kedougou to develop a disseminated infection after exposure to DENV-3 and DENV-1. We have exposed sylvatic and urban population of Ae. aegypti from Senegal to bloomeals containing dengue serotype 1 and 3. At different incubation period, individual mosquito legs/wings and bodies were tested for virus presence using real time RT-PCR to estimate the infection and dissemination rates. The data indicated low susceptibility to DENV-3 (infection: 2.4-15.2%, and dissemination rates: 0-8.3%) and higher susceptibility to DENV-1 (infection and dissemination rates up to 50%). Aedes aegypti from Senegal seem able to develop a disseminated infection of DENV-1 and DENV-3. Further studies are needed to test their ability to transmit the two serotypes. © 2014 John Wiley & Sons Ltd.
Full Text Available Culex bidens and C. interfor, implicated in arbovirus transmission in Argentina, are sister species, only distinguishable by feature of the male genitalia; however, intermediate specimens of the species in sympatry have been found. Fourth-instar larvae and females of both species share apomorphic features, and this lack of clear distinction creates problems for specific identification. Geometric morphometric traits of these life stages also do not distinguish the species. The aim of the present study was to assess the taxonomic status of C. bidens and C. interfor using two mitochondrial genes and to determine the degree of their reproductive isolation using microsatellite loci. Sequences of the ND4 and COI genes were concatenated in a matrix of 993 nucleotides and used for phylogenetic and distance analyses. Bayesian and maximum parsimony inferences showed a well resolved and supported topology, enclosing sequences of individuals of C. bidens (0.83 BPP, 73 BSV and C. interfor (0.98 BPP, 97 BSV in a strong sister relationship. The mean K2P distance within C. bidens and C. interfor was 0.3% and 0.2%, respectively, and the interspecific variation was 2.3%. Bayesian clustering also showed two distinct mitochondrial lineages. All sequenced mosquitoes were successfully identified in accordance with the best close match algorithm. The low genetic distance values obtained indicate that the species diverged quite recently. Most morphologically intermediate specimens of C. bidens from Córdoba were heterozygous for the microsatellite locus GT51; the significant heterozygote excess observed suggests incomplete reproductive isolation. However, C. bidens and C. interfor should be considered good species: the ventral arm of the phallosome of the male genitalia and the ND4 and COI sequences are diagnostic characters.
A list of mosquito species of the Brazilian State of Pernambuco, including the first report of Haemagogus janthinomys (Diptera: Culicidae, yellow fever vector and 14 other species (Diptera: Culicidae Lista de espécies de mosquitos do Estado de Pernambuco e primeiro relato de Haemagogus janthinomys (Diptera: Culicidae vetor de febre amarela silvestre e outras 14 espécies (Diptera: Culicidae
Nádia Consuelo Aragão
Full Text Available INTRODUCTION: Besides mosquito species adapted to urban environments (Culex quinquefasciatus, Aedes aegypti and Aedes albopictus, only 15 species of Anopheles had been recorded in the State of Pernambuco. METHODS: Human-landing mosquitoes were collected in Dois Irmãos Park, in Recife. RESULTS: The first report for the state of Haemagogus janthinomys, an important vector of yellow fever virus, and 14 other species, including Trichoprosopon lampropus, a first reported for Brazil. CONCLUSIONS: The mosquito fauna in the area is diversified and has potential medical and veterinary importance.INTRODUÇÃO: Além de mosquitos adaptados ao ambiente urbano (Culex quinquefasciatus, Aedes aegypti e Ae. albopictus, apenas 15 espécies de Anopheles haviam sido relatadas no Estado de Pernambuco. MÉTODOS: Mosquitos que pousavam em humanos no Parque Dois Irmãos, em Recife foram coletados. RESULTADOS: Haemagogus janthinomys, importante vetor de vírus de febre amarela, e outras 14 espécies são relatadas pela primeira vez no estado, incluindo Trichoprosopon lampropus, relatado pela primeira vez no Brasil. CONCLUSÕES: A fauna de mosquitos na área é muito diversificada e tem potencial importância médica e veterinária.
Jéssica Barreto Lopes Silva
Full Text Available Dengue represents a serious threat to human health, with billions of people living at risk of the disease. Wolbachia pipientis is a bacterial endosymbiont common to many insect species. Wolbachia transinfections in mosquito disease vectors have great value for disease control given the bacterium's ability to spread into wild mosquito populations, and to interfere with infections of pathogens, such as dengue virus. Aedes fluviatilis is a mosquito with a widespread distribution in Latin America, but its status as a dengue vector has not been clarified. Ae. fluviatilis is also naturally infected by the wFlu Wolbachia strain, which has been demonstrated to enhance infection with the avian malarial parasite Plasmodium gallinaceum. We performed experimental infections of Ae. fluviatilis with DENV-2 and DENV-3 isolates from Brazil via injection or oral feeding to provide insight into its competence for the virus. We also examined the effect of the native Wolbachia infection on the virus using a mosquito line where the wFlu infection had been cleared by antibiotic treatment. Through RT-qPCR, we observed that Ae. fluviatilis could become infected with both viruses via either method of infection, although at a lower rate than Aedes aegypti, the primary dengue vector. We then detected DENV-2 and DENV-3 in the saliva of injected mosquitoes, and observed that injection of DENV-3-infected saliva produced subsequent infections in naïve Ae. aegypti. However, across our data we observed no difference in prevalence of infection and viral load between Wolbachia-infected and -uninfected mosquitoes, suggesting that there is no effect of wFlu on dengue virus. Our results highlight that Ae. fluviatilis could potentially serve as a dengue vector under the right circumstances, although further testing is required to determine if this occurs in the field.
Rotraut A. G. B. Consoli
Full Text Available Several larval and pupal products of Aedes fluviatilis (Lutz were tested for their influence on the oviposition behaviour of females of the same species. Significant (alfa = 0,05 atractiveness was shown by: larval water, previously containing 5 to 15 larvae/1,5 ml; larval water, preserved up to 38 days; evaporate and reconstructed larval water extracts up to 2 years after production and water filtered through fresh or dried ground larvae. hexanic larval water extracts and water filtered through fresh or dired ground pupae did not influence oviposition.Estudou-se a influência sobre o comportamento de oviposição das fêmeas de Aedes fluviatilis (Lutz de produtos derivados das formas imaturas da mesma espécie. As fêmeas foram atraídas significativamente (x=0,05 por ocasião da ovoposição por: água destilada que contivera 5 ou 15 larvas/1,5 ml, a mesma água (5 larvas/1,5 mlapós sua preservação por 38 dias; extratos evaporados e reconstituídos de água que conteve larvas, por até dois anos a sua produção, e filtrados de macerados frescos e secos de larvas. Extratos hexânicos de água que conteve larvas e filtrados de macerados descos e secos de pupas não atraíram a ovoposição das fêmeas.
Background Development rates of Aedes aegypti are known to vary with respect to many abiotic and biotic factors including temperature, resource availability, and intraspecific competition. The relative importance of these factors and their interactions are not well established across populations. We performed meta-analysis on a dataset of development rate estimates from 49 studies. Results Meta-analytic results indicated that the environmental factor of temperature is sufficient to explain development rate variability in Ae. aegypti. While diet and density may greatly impact other developmental phenotypes, these results suggest that for development rate these factors should never be considered to the exclusion of temperature. The effect of temperature on development rate is not homogenous or constant. The sources of heterogeneity of the effect of temperature are difficult to analyze due to lack of consistent reporting of larval rearing methods. Conclusions Temperature is the most important ecological determinant of development rate in Ae. aegypti, but its effect is heterogeneous. Ignoring this heterogeneity is problematic for models of vector population and vector-borne disease transmission. PMID:24495345
Chou, Lee Yiung; Dykes, Gary A; Wilson, Robyn F; Clarke, Charles M
Nepenthes pitcher plants are colonized by a variety of specialized arthropods. As Aedes mosquitoes are container breeders, Nepenthes pitchers are a potential candidate oviposition site for vector species, such as Aedes aegypti (L.) and Aedes albopictus (Skuse). However, Aedes spp. are not commonly encountered in Nepenthes pitchers, and the environment inside the pitchers of some species is lethal to them. One exception is Nepenthes ampullaria Jack, whose pitchers are known to be colonized by Ae. albopictus on very rare occasions. Given that Ae. albopictus larvae can survive in N. ampullaria pitcher fluids, we sought to determine why pitcher colonization is rare, testing the hypothesis that gravid Aedes mosquitoes are deterred from ovipositing into container habitats that have similar characteristics to N. ampullaria pitchers. Using plastic ovitraps of different sizes, colors, and with different types of fluids (based on the characteristics of N. ampullaria pitchers), we compared oviposition rates by Aedes mosquitoes in urban and rural areas within the geographical range of N. ampullaria near Kuala Lumpur, Malaysia. Ovitraps that were black and large (>250-ml capacity) accumulated significantly more eggs than ovitraps that were smaller, or green in color. In terms of size and color, small, green ovitraps are analogous to N. ampullaria pitchers, indicating that these pitchers are not particularly attractive to gravid Ae. albopictus. Although Aedes spp. are capable of colonizing N. ampullaria pitchers, the pitchers are relatively unattractive to gravid females and do not represent a significant habitat for larvae of dengue vectors at present. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Essential oils are potential alternatives to synthetic insecticides because they have low mammalian toxicity, degrade rapidly in the environment, and possess complex mixtures of bioactive constituents with multi-modal activity against the target insect populations. Twenty one essential oils were ini...
Recent research in mosquito population genetics suggests that interpopulation hybridization has likely contributed to the rapid spread of the container-breeding mosquitoes. Here, I used laboratory experiments to investigate whether interpopulation Aedes (Stegomyia) albopictus (Skuse) F1 and F2 hybrids exhibit higher fitness than parental populations, and whether hybrid mosquito performance is related to infection by the coevolved protozoan parasite Ascogregarina taiwanensis (Lien and Levine). Overall, there were significant differences in development time, wing length, and survival between the two parental mosquito populations, but no difference in per capita growth rate r. Hybrid mosquitoes were generally intermediate in phenotype to the parentals, except that F2 females were significantly larger than the midparent average. In addition, As. taiwanensis parasites produced fewest oocysts when they were reared in hosts of hybrid origin. These data suggest that hybridization between previously isolated mosquito populations can result in slight increases in potential mosquito reproductive success, via increased hybrid body size, and via the temporary escape from coevolved parasites. These findings are significant because studies have shown that even slight hybrid vigor can have positive fitness consequences for population persistence. Although this was a laboratory experiment extending only to the F2 generation, many other invasive insects also carry coevolved parasites, and thus the patterns seen in this mosquito system may be broadly relevant. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
O'Donnell, Kyle L; Bixby, Mckenzie A; Morin, Kelsey J; Bradley, David S; Vaughan, Jefferson A
Zika virus is an emerging arbovirus of humans in the western hemisphere. With its potential spread into new geographical areas, it is important to define the vector competence of native mosquito species. We tested the vector competency of Aedes vexans (Meigen) from the Lake Agassiz Plain of northwestern Minnesota and northeastern North Dakota. Aedes aegypti (L.) was used as a positive control for comparison. Mosquitoes were fed blood containing Zika virus and 2 wk later were tested for viral infection and dissemination. Aedes vexans (n = 60) were susceptible to midgut infection (28% infection rate) but displayed a fairly restrictive midgut escape barrier (3% dissemination rate). Cofed Ae. aegypti (n = 22) displayed significantly higher rates of midgut infection (61%) and dissemination (22%). To test virus transmission, mosquitoes were inoculated with virus and 16-17 d later, tested for their ability to transmit virus into fluid-filled capillary tubes. Unexpectedly, the transmission rate was significantly higher for Ae. vexans (34%, n = 47) than for Ae. aegypti (5%, n = 22). The overall transmission potential for Ae. vexans to transmit Zika virus was 1%. Because of its wide geographic distribution, often extreme abundance, and aggressive human biting activity, Ae. vexans could serve as a potential vector for Zika virus in northern latitudes where the conventional vectors, Ae. aegypti and Ae. albopictus Skuse, cannot survive. However, Zika virus is a primate virus and humans are the only amplifying host species in northern latitudes. To serve as a vector of Zika virus, Ae. vexans must feed repeatedly on humans. Defining the propensity of Ae. vexans to feed repeatedly on humans will be key to understanding its role as a potential vector of Zika virus. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Faull, Katherine J; Williams, Craig R
Aedes notoscriptus and Aedes aegypti are both peri-domestic, invasive container-breeding mosquitoes. While the two potential arboviral vectors are bionomically similar, their sympatric distribution in Australia is limited. In this study, analyses of Ae. aegypti and Ae. notoscriptus eggs were enabled using scanning electron microscopy. Significant variations in egg length to width ratio and outer chorionic cell field morphology between Ae. aegypti and Ae. notoscriptus enabled distinction of the two species. Intraspecific variations in cell field morphology also enabled differentiation of the separate populations of both species, highlighting regional and global variation. Our study provides a comprehensive comparative analysis of inter- and intraspecific egg morphological and morphometric variation between two invasive container-breeding mosquitoes. The results indicate a high degree of intraspecific variation in Ae. notoscriptus egg morphology when compared to the eggs of Ae. aegypti. Comparative morphological analyses of Ae. aegypti and Ae. notoscriptus egg attributes using SEM allows differentiation of the species and may be helpful in understanding egg biology in relation to biotope of origin. Copyright © 2016 Elsevier Ltd. All rights reserved.
Bargielowski, I E; Lounibos, L P; Shin, D; Smartt, C T; Carrasquilla, M C; Henry, A; Navarro, J C; Paupy, C; Dennett, J A
Aedes aegypti and Aedes albopictus, two important vectors of the dengue and chikungunya viruses to humans, often come in contact in their invasive ranges. In these circumstances, a number of factors are thought to influence their population dynamics, including resource competition among the larval stages, prevailing environmental conditions and reproductive interference in the form of satyrization. As the distribution and abundance of Ae. aegypti and Ae. albopictus have profound epidemiological implications, understanding the competitive interactions that influence these patterns in nature is important. While evidence for resource competition and environmental factors had been gathered from the field, the evidence for reproductive interference, though strongly inferred through laboratory trials, remained sparse (one small-scale field trial). In this paper we demonstrate that low rates (1.12-3.73%) of interspecific mating occur in nature among populations of these species that have co-existed sympatrically from 3 to 150yrs. Finally this report contributes a new species-specific primer set for identifying the paternity of sperm extracted from field collected specimens. Copyright © 2015 Elsevier B.V. All rights reserved.
Calvez, Elodie; Guillaumot, Laurent; Girault, Dominique; Richard, Vaea; O'Connor, Olivia; Paoaafaite, Tuterarii; Teurlai, Magali; Pocquet, Nicolas; Cao-Lormeau, Van-Mai; Dupont-Rouzeyrol, Myrielle
Dengue virus (DENV) is the arbovirus with the highest incidence in New Caledonia and in the South Pacific region. In 2012-2014, a major DENV-1 outbreak occurred in New Caledonia. The only known vector of DENV in New Caledonia is Aedes aegypti but no study has yet evaluated the competence of New Caledonia Ae. aegypti populations to transmit DENV. This study compared the ability of field-collected Ae. aegypti from different locations in New Caledonia to transmit the DENV-1 responsible for the 2012-2014 outbreak. This study also aimed to compare the New Caledonia results with the vector competence of Ae. aegypti from French Polynesia as these two French countries have close links, including arbovirus circulation. Three wild Ae. aegypti populations were collected in New Caledonia and one in French Polynesia. Female mosquitoes were orally exposed to DENV-1 (10 6 FFU/ml). Mosquito bodies (thorax and abdomen), heads and saliva were analyzed to measure infection, dissemination, transmission rates and transmission efficiency, at 7, 14 and 21 days post-infection (dpi), respectively. DENV-1 infection rates were heterogeneous, but dissemination rates were high and homogenous among the three Ae. aegypti populations from New Caledonia. Despite this high DENV-1 dissemination rate, the transmission rate, and therefore the transmission efficiency, observed were low. Aedes aegypti population from New Caledonia was less susceptible to infection and had lower ability to transmit DENV-1 than Ae. aegypti populations from French Polynesia. This study suggests that even if susceptible to infection, the New Caledonian Ae. aegypti populations were moderately competent vectors for DENV-1 strain from the 2012-2014 outbreak. These results strongly suggest that other factors might have contributed to the spread of this DENV-1 strain in New Caledonia and in the Pacific region.
Honorio, Nildimar A.
Toxorhynchites guadeloupensis (Dyar and Knab), a poorly known mosquito species, was observed preying upon Aedes aegypti (L.) larvae, in an oviposition trap placed for routine dengue entomological surveillance, during 2003-2004 in the urban area of Boa Vista, Roraima, Brazil. This is the first report for Tx. guadeloupensis using Ae. aegypti oviposition traps as breeding places. This finding may have important consequences in the epidemiology and local dengue control since Ae. aegypti density is a basic variable in dengue prediction. Whether predation of Ae aegypti by Tx. guadeloupensis in the Amazon is of significance, is a question to be examined. Also, larval predation may be a cause for underestimation of the actual Ae aegypti numbers. Together these hypotheses need to be better investigated as they are directly related to dengue epidemiology, to the success of any outbreak prediction and surveillance program. (author)
The invasion and range expansion of Aedes albopictus (Skuse) in North America represents an outstanding opportunity to study processes of invasion, range expansion, and climatic adaptation. Furthermore, knowledge obtained from such research is relevant to developing novel strategies to control this important vector species. Substantial evidence indicates that the photoperiodic diapause response is an important adaptation to climatic variation across the range of Ae. albopictus in North America. Photoperiodic diapause is a key determinant of abundance in both space and time, and the timing of entry into and exit out of diapause strongly affects seasonal population dynamics and thus the potential for arbovirus transmission. Emerging genomic technologies are making it possible to develop high-resolution, genome-wide genetic markers that can be used for genetic mapping of traits relevant to disease transmission and phylogeographic studies to elucidate invasion history. Recent work using next-generation sequencing technologies (e.g., RNA-seq), combined with physiological experiments, has provided extensive insight into the transcriptional basis of the diapause response in Ae. albopictus. Applying this knowledge to identify novel targets for vector control represents an important future challenge. Finally, recent studies have begun to identify traits other than diapause that are affected by photoperiodism. Extending this work to identify additional traits influenced by photoperiod should produce important insights into the seasonal biology of Ae. albopictus. PMID:27354438
Combinations of female wingbeat acoustic cues and visual cues were evaluated to determine their potential for use in male Aedes aegypti (L.) traps in peridomestic environments. A modified Centers for Disease control (CDC) light trap using a 350-500 Hz frequency-sweep broadcast from a speaker as an a...
Monteiro, Laura C.C.; Souza, Jose R.B. de; Albuquerque, Cleide M.R. de
In tropical areas, where vector insects populations are particularly numerous, temperature usually range between 25 de C and 35 deg C. Considering the importance of such temperature variation in determining mosquitoes population dynamics, in this work the developmental, eclosion and survival rates of the immature stages of Aedes albopictus (Skuse) were compared under constant 25, 30 and 35 deg C (using acclimatized chambers) and environmental (25 deg C to 29 deg C) temperatures. The hatching rate was considered as total number of larvae recovered after 24h. The development period as well as larval and pupal survival rate were evaluated daily. Eclosion rate was significantly higher under environmental temperature than under the studied constant temperatures, suggesting that temperature variation may be an eclosion-stimulating factor. The mean eclosion time increased with the temperature, ranging from 2.8 h (25 deg C) to 5.2 h (35 deg C). The larval period was greatly variable inside each group, although it did not differ significantly amongst groups (11.0 +- 4.19 days), with individuals showing longer larval stages in water at 35 deg C (12.0 +- 4.95 days) and environmental temperature (13.6 +- 5.98 days). Oppositely, survival was strongly affected by the higher temperature, where only one individual lived through to adult phase. The results suggest that population of Ae. albopictus from Recife may be adapting to increasing of environmental temperatures and that the limiting temperature to larval development is around 35 deg C. (author)
Baldacchino, Frédéric; Arnoldi, Daniele; Lapère, Charlotte; Rosà, Roberto; Montarsi, Fabrizio; Capelli, Gioia; Rizzoli, Annapaola
Aedes (Hulecoeteomyia) koreicus (Edwards) and Aedes (Stegomyia) albopictus (Skuse) are two invasive mosquito species well established in northeastern Italy, and these two species may co-occur in artificial larval habitats such as tires, buckets, drums, and catch basins. Because Ae. albopictus has been shown experimentally to be a superior competitor to several mosquito species, we investigated larval competition between Ae. koreicus and Ae. albopictus using two diet levels (low level and high level) and 10 Ae. albopictus: Ae. koreicus density combination levels (30:0, 60:0, 15:15, 30:30, 10:20, 20:10, 20:40, 40:20, 0:60, and 0:30). A multivariate analysis (MANOVA) demonstrated a significant effect of the density combination on Ae. koreicus survivorship, female development time, and female wing length considered simultaneously in low-level diet and high-level diet treatments. Pairwise comparisons across low-level diet treatments showed a significant reduction of Ae. koreicus survivorship in 20:10 combination treatments (i.e. 20 Ae. albopictus and 10 Ae. koreicus larvae) compared to 10:20, 20:40, and 30:30 combination treatments, while no difference was detected for Ae. albopictus between density combination treatments. Furthermore, Ae. albopictus developed faster than Ae. koreicus regardless of diet and density combination treatments. Our results show weak larval competition between Ae. koreicus and Ae. albopictus with a slight advantage of the latter species. On the other hand, the presence of Ae. albopictus seems to favor the emergence of larger Ae. koreicus females. We suggest that factors such as habitats preferences or seasonal distributions may be determinant for the invasion success of Ae. koreicus. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
virus , chikungunya, Zika and Bouboui viruses have been isolated from Ae. africanus and Ae. opok in the Central African Republic (Germain et al., 1978...J., M. C. Williams, J. P. Woodall, D. I. H. Simpson, and L. K. H. Goma. 1964. Twelve isolations of Zika virus from Aedes (Stegomyiu) africanus...du Banco), Abidjan, Ivory Coast. Medical importance. -Unknown. However, Aedes africanus has been recog- nized as one of the most important virus
Full Text Available Culex quinquefasciatus is the vector responsible for serious disease filariasis among human beings. Plant derived products have received increased attention from scientists as they serve as a rich source for novel natural substances possessing insecticidal properties which are safe to human and ecosystem. During the last decade, various studies on natural plant products against vector mosquito indicate them as possible alternatives to chemical and synthetic insecticides for mosquito control. In the present study, the crude hexane and aqueous extract of Nerium oleander flowers were reported for larvicidal activity against the filarial vector, Culex quinquefasciatus. Mortality was observed for 24 and 48 hours. Hexane flower extract exhibited highest larvicidal activity with a LC50 value of 102.54 ppm and 61.11ppm after 24 and 48 hours respectively. Further investigations are needed to elucidate this activity against a wide range of all stages of mosquito species and also the active ingredient(s of the extract responsible for larvicidal activity should be identified.
To determine the ovicidal efficacy of different solvent leaf extracts of Ageratina adenophora against dengue vector Aedes aegypti . Methods: The ovicidal efficacy of the crude leaf extracts of A. adenophora with five different solvents (hexane, benzene, chloroform, ethyl acetate, methanol) and was ...
Mosquitoes are blood-feeding insects and serve as the most important vectors for spreading human diseases such as malaria, yellow fever, dengue fever, and filariasis. The continued use of synthetic insecticides has resulted in resistance in mosquitoes. Synthetic insecticides are toxic and affect the...
Six known thiophenes, 5-(3,4-diacetoxybut-1-ynyl)-2,2'-bithiophene (3), 2-(penta-1,3-diynyl)-5-(3,4-diacetoxybut-1-ynyl)thiophene (4), 5-(4-acetoxy-3-hydroxybut-1-ynyl)-2,2'-bithiophene (5), 2-(penta-1,3-diynyl)-5-(4-acetoxy-3-hydroxybut-1-ynyl)thiophene (6), 2-(penta-1,3-diynyl)-5-(3-acetoxy-4-hydr...
Mosquito-borne diseases with an economic impact create loss in commercial and labor outputs, particularly in countries with tropical and subtropical climates. Mosquito control is facing a threat because of the emergence of resistance to synthetic insecticides. Extracts from plants may be alternativ...
Al Thbiani Aziz
Full Text Available Objective: To examine the insecticide susceptibility of Aedes aegypti (Ae. aegypti from various sites in Makkah City, Saudi Arabia. Methods: This was examined based on WHO standard procedures. Results: The larvae of Ae. aegypti were susceptible to all larvicides examined, but this susceptibility was more pronounced in wild populations, which tended to show tolerance to icon. Icon was the most effective larvicide with LC 50 values of 0.007 ppm and 0.012 ppm for the laboratory and field strains, respectively. Ae. aegypti adults exposed to lambda-cyhalothrin showed a low mortality rate in comparison with those exposed to deltamethrin and cyfluthrin. Conclusions: The results of the present study indicate differential susceptibility between field and laboratory larval populations. Wild larvae are less susceptible to insecticide treatments than their laboratory-bred counterparts. Taken together, these results suggest that tolerance and the tendency toward resistance to commonly used insecticides are present in Ae. aegypti populations throughout Makkah City, Saudi Arabia.
Full Text Available The objective of the present work was to determine the resistance levels to deltamethrine in two populations of Aedes aegypti from Peru. Bioassays in adults were carried out following the methodology of the World Health Organization. We met resistance in the Sullana population with 70% of mortality and susceptibility in the population The Future El Porvenir with 99% of mortality.
Carmen Elisa Posso
Full Text Available Random amplified polymorphic DNA (RAPD markers were used to analyze 119 DNA samples of three Colombian Anopheles nuneztovari populations to study genetic variation and structure. Genetic diversity, estimated from heterozygosity, averaged 0.34. Genetic flow was greater between the two populations located in Western Colombia (F ST: 0.035; Nm: 6.8 but lower between these two and the northeastern population (F ST: 0.08; Nm: 2.8. According to molecular variance analysis, the genetic distance between populations was significant (phiST 0.1131, P < 0.001. The variation among individuals within populations (phiST 0.8869, P < 0.001was also significant, suggesting a greater degree of population subdivision, not considered in this study. Both the parameters evaluated and the genetic flow suggest that Colombian An. nuneztovari populations are co-specific.
Šebesta, Oldřich; Halouzka, Jiří; Hubálek, Zdeněk; Juřicová, Zina; Rudolf, Ivo; Šikutová, Silvie; Svobodová, Petra; Reiter, P.
Roč. 35, č. 1 (2010), s. 156-162 ISSN 1081-1710 EU Projects: European Commission(XE) 10284 - EDEN Institutional research plan: CEZ:AV0Z60930519 Keywords : mosquito es * Anopheles * Aedes * Culex * climate * ecology Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology Impact factor: 1.256, year: 2010
Somers, Gerard; Brown, Julia E; Barrera, Roberto; Powell, Jeffrey R
Dengue viruses, primarily transmitted by the mosquito Aedes aegypti (L.), affect an estimated 50-100 million people yearly. Traditional approaches to control mosquito population numbers, such as the use of pesticides, have had only limited success. Atypical mosquito behavior may be one reason why current vector control efforts have been less efficacious than expected. In Puerto Rico, for example, adult Ae. aegypti have been observed emerging from septic tanks. Interestingly, adults emerging from septic tanks are larger on average than adults collected from surface containers. To determine whether adults colonizing septic tanks constitute a separate Ae. aegypti population, we used 12 previously validated microsatellite loci to examine adult mosquitoes collected from both septic tanks and surface containers, but found no evidence to suggest genetic differentiation. Size differences between septic tank and surface mosquitoes were reduced when nutrient levels were held constant across experimental groups. Despite the absence of evidence suggesting a genetic difference between experimental groups in this study, Ae. aegypti emerging from septic tanks may still represent a more dangerous phenotype and should be given special consideration when developing vector control programs and designing public health interventions in the future.
Smallegange, R.C.; Knols, B.G.J.; Takken, W.
Females of the African malaria vector, Anopheles gambiae Giles sensu stricto, use human volatiles to find their blood-host. Previous work has shown that ammonia, lactic acid, and aliphatic carboxylic acids significantly affect host orientation and attraction of this species, In the current study,
A field survey, three outdoor cage enclosure experiments, and laboratory studies were conducted to elucidate the impact of the invasive aquatic weeds Eichhornia crassipes (floating water hyacinth), Ludwigia hexapetala (emergent water yellow-primrose), and Egeria densa (submersed Brazilian waterweed)...
Full Text Available A preliminary study on larvicidal activity against laboratory-colonized Anopheles cracens mosquitos revealed that five of ten plant oils at concentration of 100 ppm showed 95–100% larval mortality. The essential oils of five plants, including Piper sarmentosum, Foeniculum vulgare, Curcuma longa, Myristica fragrans, and Zanthoxylum piperitum, were then selected for chemical analysis, dose-response larvicidal experiments, and combination-based bioassays. Chemical compositions analyzed by gas chromatography coupled to mass spectrometry demonstrated that the main component in the oil derived from P. sarmentosum, F. vulgare, C. longa, M. fragrans, and Z. piperitum was croweacin (71.01%, anethole (63.00%, ar-turmerone (30.19%, safrole (46.60%, and 1,8-cineole (21.27%, respectively. For larvicidal bioassay, all five essential oils exerted promising efficacy in a dose-dependent manner and different performances on A. cracens after 24 hours of exposure. The strongest larvicidal potential was established from P. sarmentosum, followed by F. vulgare, C. longa, M. fragrans, and Z. piperitum, with LC50 values of 16.03, 32.77, 33.61, 40.00, and 63.17 ppm, respectively. Binary mixtures between P. sarmentosum, the most effective oil, and the others at the highest ratio were proved to be highly efficacious with a cotoxicity coefficient value greater than 100, indicating synergistic activity. Results of mixed formulations of different essential oils generating synergistic effects may prove helpful in developing effective, economical, and ecofriendly larvicides, as favorable alternatives for mosquito management.
Barnard, D R
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.
Carvajal, José Joaquín; Honorio, Nildimar Alves; Díaz, Silvia Patricia; Ruiz, Edinso Rafael; Asprilla, Jimmy; Ardila, Susanne; Parra-Henao, Gabriel
Aedes albopictus is widely distributed around the world. Its introduction to the Americas occurred in 1985 and it is considered a potential vector of dengue viruses and one of the principal vectors of chikungunya virus. In Colombia, this species was reported for the first time in Leticia (Amazonas) in 1998, followed by Buenaventura (Valle del Cauca) in 2001, Barrancabermeja (Santander) in 2010, and Medellín (Antioquia) in 2011. So far, this species has been reported in ten departments of the country. Objective: To report the finding of A. albopictus in the city of Istmina, Chocó, and its implications for public health. Materials and methods: In January 2015, we conducted an inspection of immature stages of Aedes spp. in breeding sites in the neighborhoods of San Agustín, Santa Genoveva and Subestación in Istmina, Chocó. The immature stages collected in this municipality were identified at the Unidad de Entomología of the Laboratorio de Salud Pública Departamental de Chocó, and confirmed by the Laboratorio de Entomología, Red Nacional de Laboratorios, Instituto Nacional de Salud, in Bogotá. In January 2015, twelve A. albopictus larvae were found in the breeding sites located in Subestación and San Agustín neighborhoods. The occurrence of A. albopictus in the municipality of Istmina underlines the importance of strengthening continuous entomological surveillance strategies at national and local levels in the country, especially in Istmina and its surrounding municipalities.
Cuéllar-Jiménez, María Elena; Velásquez-Escobar, Olga Lucía; González-Obando, Ranulfo; Morales-Reichmann, Carlos Andrés
Aedes albopictus is the second most important dengue virus vector in the Asian southeast after Aedes aegypti. Its entrance into the Americas occurred in 1985, and laboratory studies performed show its potential as a vector in this continent as well. In Colombia, this species has been reported in Leticia (Amazonas) in 1998 and Buenaventura (Valle del Cauca) in 2001. The latest discoveries show that this mosquito continues to advance toward the country's interior. To inform that the presence of A. albopictus is documented in the city of Cali, Valle del Cauca, Colombia. Since 2002, weekly sampling has been performed using larval traps located at seventeen stations. The identification of the A. albopictus species, was carried out in the Unidad de Entomología, Laboratorio de Salud Pública Departamental. These identifications were confirmed in the Entomology Laboratory at Universidad del Valle and the National Institute of Health in Bogotá. From April to June of 2006, larvae of A. albopictus were found in six sampling stations located between northwest and northeast of Cali, one of them in the suburban area of the Yumbo city. The control of A. aegypti and A. albopictus must be integrated into a single program. The surveillance in the cities and nearest departments must be intensified with the objective of limiting the advancement of A. albopictus.
Full Text Available Variations in the biology and ecology and the high level of genetic polymorphism of malaria vectors in Africa highlight the value of mapping their spatial distribution to enhance successful implementation of integrated vector management. The objective of this study was to collate data on the relative frequencies of Anopheles gambiae s.s. and An. arabiensis mosquitoes in Mali, to assess their association with climate and environmental covariates, and to produce maps of their spatial distribution. Bayesian geostatistical logistic regression models were fitted to identify environmental determinants of the relative frequencies of An. gambiae s.s. and An. arabiensis species and to produce smooth maps of their geographical distribution. The frequency of An. arabiensis was positively associated with the normalized difference vegetation index, the soil water storage index, the maximum temperature and the distance to water bodies. It was negatively associated with the minimum temperature and rainfall. The predicted map suggests that, in West Africa, An. arabiensis is concentrated in the drier savannah areas, while An. gambiae s.s. prefers the southern savannah and land along the rivers, particularly the inner delta of Niger. Because the insecticide knockdown resistance (kdr gene is reported only in An. gambiae s.s. in Mali, the maps provide valuable information for vector control. They may also be useful for planning future implementation of malaria control by genetically manipulated mosquitoes.
of elephantiasis , with 83 Americans and 28 natives admitted during the year with dengue fever, No cases of malaria were known to have originated on...group, p. 109. Mosquito Systematics Vol. 8(4) 1976 -3e *South Pacific Conmission. 1951. Conference of experts on filariasis and elephantiasis . So
Eduardo S Bergo
Full Text Available Identification of Anopheles nuneztovari Gabaldón and An. goeldii Rozeboom and Gabaldón based on the male genitalia traits is discussed. An. goeldii is in the synonymy of An. nuneztovari, however, characters of the aedeagus of male genitalia distinguish both species. We hypothesize that An. goeldii may be a valid species, however, further studies using molecular characters, especially ITS2 rDNA sequences will be necessary to elucidate the taxonomic status of the species. An. konderi Galvão and Damasceno and An. forattinii Wilkerson and Sallum are registered for the first time in the state of Amapá.
condition . Both Y, and Y, are associated with species B and forms E and F; however, they show geographic variation. Chromosome Y, does not occur (or is...Heterochromatin and karyotypic differentiation of some Neotropical cactus-breeding species of the Drosophila replctu group. Genetica 60: 81-92
Allan, Sandra A; Bernier, Ulrich R; Kline, Daniel L
The role of lactic acid was evaluated for attraction of Culex nigripalpus, Culex quinquefasciatus, Culex tarsalis, and Aedes aegypti in the laboratory using a dual-port olfactometer. When lactic acid was combined with chicken odor, attraction was increased for Cx. quinquefasciatus compared to chicken odor alone but not for Cx. nigripalpus, Cx. tarsalis, and Ae. aegypti. Lactic acid combined with hand odor did not change attraction of Cx. tarsalis and Ae. aegypti but decreased attraction of Cx. nigripalpus and Cx. quinquefasciatus. The addition of lactic acid to CO(2) increased attraction of Ae. aegypti and Cx. quinquefasciatus but reduced attraction of Cx. nigripalpus and Cx. tarsalis. Use of commercial lactic acid baits with CO(2) resulted in a similar trend except for Cx. nigripalpus which showed no difference. A blend of lactic acid, acetone, and dimethyl disulfide was attractive to Ae. aegypti (63.4%) but elicited low responses by all Culex spp. (1.3-26.8%). Addition of the blend to CO(2) increased attraction of Ae. aegypti and Cx. quinquefasciatus but reduced attraction of Cx. nigripalpus and Cx. tarsalis. The mixture of compounds plus CO(2) was as attractive as a hand for Cx. quinquefasciatus, Cx. tarsalis, and Ae. aegypti. © 2010 The Society for Vector Ecology.
Ibañez-Justicia, Adolfo; Cianci, Daniela
Landscape modifications, urbanization or changes of use of rural-agricultural areas can create more favourable conditions for certain mosquito species and therefore indirectly cause nuisance problems for humans. This could potentially result in mosquito-borne disease outbreaks when the nuisance is caused by mosquito species that can transmit pathogens. Anopheles plumbeus is a nuisance mosquito species and a potential malaria vector. It is one of the most frequently observed species in the Netherlands. Information on the distribution of this species is essential for risk assessments. The purpose of the study was to investigate the potential spatial distribution of An. plumbeus in the Netherlands. Random forest models were used to link the occurrence and the abundance of An. plumbeus with environmental features and to produce distribution maps in the Netherlands. Mosquito data were collected using a cross-sectional study design in the Netherlands, from April to October 2010-2013. The environmental data were obtained from satellite imagery and weather stations. Statistical measures (accuracy for the occurrence model and mean squared error for the abundance model) were used to evaluate the models performance. The models were externally validated. The maps show that forested areas (centre of the Netherlands) and the east of the country were predicted as suitable for An. plumbeus. In particular high suitability and high abundance was predicted in the south-eastern provinces Limburg and North Brabant. Elevation, precipitation, day and night temperature and vegetation indices were important predictors for calculating the probability of occurrence for An. plumbeus. The probability of occurrence, vegetation indices and precipitation were important for predicting its abundance. The AUC value was 0.73 and the error in the validation was 0.29; the mean squared error value was 0.12. The areas identified by the model as suitable and with high abundance of An. plumbeus, are consistent with the areas from which nuisance was reported. Our results can be helpful in the assessment of vector-borne disease risk.
Ruiling, Zhang; Tongkai, Liu; Zhendong, Huang; Guifen, Zhuang; Dezhen, Ma; Zhong, Zhang
Aedes albopictus has been described as one of the 100 worst invasive species in the world. This mosquito originated from southeastern Asia and currently has a widespread presence in every continent except Antarctica. The rapid global expansion of Ae. albopictus has increased public health concerns about arbovirus-related disease threats. Adaptation, adaption to novel areas is a biological challenge for invasive species, and the underlying processes can be studied at the molecular level. In this study, genetic analysis was performed using mitochondrial gene NADH dehydrogenase subunit 5 (ND5), based on both native and invasive populations. Altogether, 38 haplotypes were detected with H1 being the dominant and widely distributed in 21 countries. Both phylogenetic and network analyses supported the existence of five clades, with only clade I being involved in the subsequent global spread of Asian tiger mosquito. The other four clades (II, III, IV and V) were restricted to their original regions, which could be ancestral populations that had diverged from clade I in the early stages of evolution. Neutrality tests suggested that most of the populations had experienced recent expansion. Analysis of molecular variance and the population-pair statistic F ST revealed that most populations lacked genetic structure, while high variability was detected within populations. Multiple and independent human-mediated introductions may explain the present results. Copyright © 2018 Elsevier B.V. All rights reserved.
Ruiling, Zhang; Peien, Leng; Xuejun, Wang; Zhong, Zhang
Aedes albopictus is one of the most invasive species, which can carry Dengue virus, Yellow fever virus and more than twenty arboviruses. Based on mitochondrial gene cytochrome c oxidase I (COI) and samples collected from 17 populations, we investigated the molecular character and genetic diversity of Ae. albopictus from China. Altogether, 25 haplotypes were detected, including 10 shared haplotypes and 15 private haplotypes. H1 was the dominant haplotype, which is widely distributed in 13 populations. Tajima'D value of most populations was significantly negative, demonstrating that populations experienced rapid range expansion recently. Most haplotypes clustered together both in phylogenetic and median-joining network analysis without clear phylogeographic patterns. However, neutrality tests revealed shallow divergences among Hainan and Guangxi with other populations (0.15599 ≤ F ST ≤ 0.75858), which probably due to interrupted gene flow, caused by geographical isolations. In conclusion, Ae. albopictus populations showed low genetic diversity in China.
Blažejová, Hana; Šebesta, Oldřich; Rettich, F.; Mendel, Jan; Čabanová, V.; Miterpáková, M.; Betášová, Lenka; Peško, Juraj; Hubálek, Zdeněk; Kampen, H.; Rudolf, Ivo
Roč. 117, č. 1 (2018), s. 315-321 ISSN 0932-0113 R&D Projects: GA ČR(CZ) GA16-20054S Institutional support: RVO:68081766 Keywords : Anophelinae * Maculipennis complex * Anopheles daciae * Mosquitoes * Cryptic species * Vector-borne diseases Subject RIV: EG - Zoology Impact factor: 2.329, year: 2016
Calderón-Arguedas, Olger; Troyo, Adriana; Solano, Mayra E; Avendaño, Adrián; Beier, John C
Field studies were conducted to determine the mosquito species richness in the urban area of Greater Puntarenas in Costa Rica. Two cross-sectional entomological surveys were performed in seven localities of Puntarenas: one survey was performed during the wet season and the other during the dry season. The sections evaluated were determined by applying a stratified cluster sampling method using satellite imagery, and a sample of 26 cells (100 x 100m) was selected for the study. The number of cells per locality was proportional to the area of each locality. The presence of mosquito larvae and pupae in water-filled artificial and natural containers was determined in each cell. Infestation was expressed as a diversity index per type of container (Ii). Eight types of larvae were identified (Aedes aegypti, Culex quinquefasciatus, Culex interrogator, Culex nigripalpus, Culex corniger, Culex tarsalis, Limatus durhamii and Toxorhynchites theobaldi) and in two cases it was only possible to identify the genus (Culex sp. and Uranotaenia sp.). A. aegypti was the most common species followed by C. quinquefascitus. Diversity of wet environments can explain the co-occurrence of various culicid species in some localities. Although A. aegypti is the only documented disease vector in the area, C quinquefasciatus, C nigripalpus, and the other species of Culex could be considered potential vectors of other pathogens. The presence and ecology of all mosquito species should be studied to optimize surveillance and prevention of dengue and to prevent the emergence of other mosquito-transmitted diseases.
Endersby-Harshman, Nancy M; Wuliandari, Juli Rochmijati; Harshman, Lawrence G; Frohn, Verena; Johnson, Brian J; Ritchie, Scott A; Hoffmann, Ary A
Although pesticide resistance is common in insect vectors of human diseases, the evolution of resistance might be delayed if management practices are adopted that limit selection of resistance alleles. Outbreaks of dengue fever have occurred in Queensland, Australia, since the late 1800s, leading to ongoing attempts to control the mosquito vector, Aedes aegypti (L.). Since the 1990s, pyrethroid insecticides have been used for this purpose, but have been applied in a strategic manner with a variety of delivery methods including indoor residual spraying, lethal ovitraps, and use of insect growth regulators as larvicides. Separate selection experiments on mosquitoes from Queensland using Type I and Type II pyrethroids did not produce resistant lines of Ae. aegypti, and bioassays of field material from Queensland showed only weak tolerance in comparison with a susceptible line. There was no evidence of knockdown resistance (kdr) mutations in Ae. aegypti from Queensland, in stark contrast to the situation in nearby southeast Asia. We suspect that careful management of pyrethroid insecticide use combined with surveillance and interception of exotic incursions has helped to maintain pyrethroid (and particularly kdr-based) susceptibility in Ae. aegypti in Australia. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Gunathilaka, P A D H N; Uduwawala, U M H U; Udayanga, N W B A L; Ranathunge, R M T B; Amarasinghe, L D; Abeyewickreme, W
Larval diet quality and rearing conditions have a direct and irreversible effect on adult traits. Therefore, the current study was carried out to optimize the larval diet for mass rearing of Aedes aegypti, for Sterile Insect Technique (SIT)-based applications in Sri Lanka. Five batches of 750 first instar larvae (L 1) of Ae. aegypti were exposed to five different concentrations (2-10%) of International Atomic Energy Agency (IAEA) recommended the larval diet. Morphological development parameters of larva, pupa, and adult were detected at 24 h intervals along with selected growth parameters. Each experiment was replicated five times. General Linear Modeling along with Pearson's correlation analysis were used for statistical treatments. Significant differences (P rate and success, sex ratio, adult success, fecundity and hatching rate of Ae. aegypti. The best quality adults can be produced at larval diet concentration of 10%. However, the 8% larval diet concentration was most suitable for adult male survival.
Sarah Susanne Übleis
Full Text Available Information on mosquito-borne filarioid helminths in Austria is scarce, but recent discoveries of Dirofilaria repens indicate autochthonous distribution of this parasite in Eastern Austria. In the current xenomonitoring study, more than 48,000 mosquitoes were collected in Eastern Austria between 2013 and 2015, using different sampling techniques and storage conditions, and were analysed in pools with molecular tools for the presence of filarioid helminth DNA. Overall, DNA of D. repens, Setaria tundra, and two unknown filarioid helminths were documented in twenty mosquito pools within the mitochondrial cox1 gene (barcode region. These results indicate that S. tundra, with roe deer as definite hosts, is common in Eastern Austria, with most occurrences in floodplain mosquitoes (e.g., Aedes vexans. Moreover, DNA of D. repens was found in an Anopheles plumbeus mosquito close to the Slovakian border, indicating that D. repens is endemic in low prevalence in Eastern Austria. This study shows that xenomonitoring is an adequate tool to analyse the presence of filarioid helminths, but results are influenced by mosquito sampling techniques, storage conditions, and molecular protocols.
Full Text Available Abstract The search for new insecticides to control dengue fever, chikungunya, and Zika vectors has gained relevance in the past decades. The aim of the present study was to evaluate the larvicidal action of essential oils (EOs from Thymus vulgaris, Salvia officinalis, Lippia origanoides, Eucalyptus globulus, Cymbopogon nardus, Cymbopogon martinii, Lippia alba, Pelargonium graveolens, Turnera diffusa, and Swinglea glutinosa on Aedes (Stegomyia aegypti. The EOs were extracted by microwave-assisted hydrodistillation and characterized by gas chromatography/mass spectrometry (GC/MS. The chemical components of the EOs were identified by linear retention indices and mass spectra. Lethal concentrations (LC50 and LC95 were determined by probit analysis using larvae of Ae. aegypti between the third and the fourth instars. All EOs achieved larvicidal activity at LC50 values lower than 115 mg/L. The lowest LC50 value (45.73 mg/L corresponded to T. vulgaris EO, whereas C. martinii EO showed the highest LC50 (LC50 = 114.65 mg/L. Some EO mixtures showed lower LC50 than oils used individually, such as the mixtures of L. origanoides + S. glutinosa (LC50 = 38.40 mg/L, T. diffusa + S. glutinosa (LC50 = 63.71 mg/L, and L. alba + S. glutinosa (LC50 = 48.87 mg/L. The main compounds of the EOs with highest larvicidal activity were thymol (42% and p-cymene (26.4%.
Ebrahimi, Babak; Shakibi, Sanam; Foster, Woodbridge A
Mosquito eggs laid on water surfaces typically hatch spontaneously soon after the embryos within them become fully formed first-instar larvae. However, we have found that Anopheles gambiae Giles, an important vector of malaria in Africa, exhibits delayed hatching until the water surface is agitated, a feature overlooked in most laboratory colonies. Agitation within 24 h postoviposition, before embryonation was complete, failed to stimulate delayed postembryonic hatching of isolated eggs on the following day (day 2), when < 1% had hatched spontaneously. However, 5 min of water agitation of these dormant pharate first-instar larvae on day 2 resulted in an almost immediate hatch of 63.3 versus 0% of nonagitated controls, plus another 3.9 versus 0.3%, respectively, during the following 24 h. With daily agitation, installment hatching occurred mainly during 2-6 d postoviposition. The mean cumulative hatch after 7 d of daily agitation was 83.1 versus 1.1% of nonagitated eggs. Experiments with eggs in groups demonstrated that egg density and activity of already-hatched larvae had no stimulatory effect. Eggs stored 1-4 wk at 25.5 or at 15.5 degrees C, and then agitated daily for 6 d at 25.5 degrees C, showed a gradual decline in viability. Viability was sustained longer at the lower temperature. Implications of agitation-induced egg hatching for rainy-season and dry-season ecology of An. gambiae are discussed. Suspended hatching and cool storage already are proving convenient for efficient mass rearing and accurate modeling of weather-based population dynamics.
Tomberlin, Jeffery K.; Rains, Glen C.; Allan, Sandy A.; Sanford, Michelle R.; Lewis, W. Joe
The ability of many insects to learn has been documented. However, a limited number of studies examining associative learning in medically important arthropods has been published. Investigations into the associative learning capabilities of Culex quinquefasciatus Say were conducted by adapting methods commonly used in experiments involving Hymenoptera. Male and female mosquitoes were able to learn a conditioned stimulus that consisted of an odor not normally encountered in nature (synthetic strawberry or vanilla extracts) in association with an unconditioned stimulus consisting of either a sugar (males and females) or blood (females) meal. Such information could lead to a better understanding of the ability of mosquitoes to locate and select host and food resources in nature.
Gouagna, Louis-Clément; Poueme, Rodrigue S; Dabiré, Kounbobr Roch; Ouédraogo, Jean-Bosco; Fontenille, Didier; Simard, Frédéric
Sugar feeding by male mosquitoes is critical for their success in mating competition. However, the facets of sugar source finding under natural conditions remain unknown. Here, evidence obtained in Western Burkina Faso indicated that the distribution of An. gambiae s.s. (M and S molecular forms) males across different peri-domestic habitats is dependent on the availability of potential sugar sources from which they obtain more favorable sites for feeding or resting. Among field-collected anophelines, a higher proportion of specimens containing fructose were found on flowering Mangifera indica (Anacardiaceae), Dolonix regia (Fabaceae), Thevetia neriifolia (Apocynaceae), Senna siamea, and Cassia sieberiana (both Fabaceae) compared to that recorded on other nearby plants, suggesting that some plants are favored for use as a sugar source over others. Y-tube olfactometer assays with newly-emerged An. gambiae s.s. exposed to odors from individual plants and some combinations thereof showed that males use odor cues to guide their preference. The number of sugar-positive males was variable in a no-choice cage assay, consistent with the olfactory response patterns towards corresponding odor stimuli. These experiments provide the first evidence both in field and laboratory conditions for previously unstudied interactions between males of An. gambiae and natural sugar sources. © 2010 The Society for Vector Ecology.
Amal Elsayed Edriss
Full Text Available Certain mosquito species are important vectors of fatal human diseases, among which Anopheles arabiensis is known to be associated with malaria transmission in different tropical and subtropical areas. Since chemical control of mosquitoes was linked with numerous drawbacks, like resistance development, the search for effective environmentally sound alternatives is urgently needed. Therefore, it was aimed by this study to evaluate some extracts prepared from two asclepiadaceous plants, viz., Solenostemma argel “Hargel” (seeds and leaves and Calotropis procera “Usher” (leaves and flowers, as natural larvicides against An. arabiensis. The main parameters included bioassays of treatments for knockdown and residual effects, besides phytochemical analysis of the tested extracts. The results revealed variable groups of secondary metabolites in the two plants, with S. argel seemed to be the richest one. Hence, S. argel extracts caused higher larval mortalities than those of C. procera. This could be ascribed to some potent secondary metabolites in the former plant, which needs further studies. Almost all the high concentrations of S. argel extracts exerted the highest knockdown effect (90% mortality after 24 h, which were comparable with those obtained by two standard insecticides. The highest doses of petroleum ether and water extracts of this plant also manifested significantly higher residual effects than the other extracts after three days following treatments, but were surpassed by the chemical insecticides thereafter. However, S. argel seed petroleum ether extract at 0.5% was the most effective of all botanicals up to three weeks of exposure. This extract needs to be evaluated under field conditions for proper exploitation as mosquito larvicide.
Osório, Hugo Costa; Zé-Zé, Líbia; Neto, Maria; Silva, Sílvia; Marques, Fátima; Silva, Ana Sofia; Alves, Maria João
The Asian tiger mosquito Aedes albopictus is an invasive mosquito originating from the Asia-Pacific region. This species is of major concern to public and veterinary health because of its vector role in the transmission of several pathogens, such as chikungunya, dengue, and Zika viruses. In Portugal, a National Vector Surveillance Network (REde de VIgilância de VEctores—REVIVE) is responsible for the surveillance of autochthonous, but also invasive, mosquito species at points of entry, such as airports, ports, storage areas, and specific border regions with Spain. At these locations, networks of mosquito traps are set and maintained under surveillance throughout the year. In September 2017, Ae. albopictus was detected for the first time in a tyre company located in the North of Portugal. Molecular typing was performed, and a preliminary phylogenetic analysis indicated a high similarity with sequences of Ae. albopictus collected in Europe. A prompt surveillance response was locally implemented to determine its dispersal and abundance, and adult mosquitoes were screened for the presence of arboviral RNA. A total of 103 specimens, 52 immatures and 51 adults, were collected. No pathogenic viruses were detected. Despite the obtained results suggest low abundance of the population locally introduced, the risk of dispersal and potential establishment of Ae. albopictus in Portugal has raised concern for autochthonous mosquito-borne disease outbreaks. PMID:29690531
Rita de Cássia Sousa-Polezzi
Full Text Available The effect of phenobarbital (PB on the induction of tolerance to the organophosphorous insecticide temephos (TE was investigated in Aedes aegypti L4 larvae submitted to two different PB-treatments:(1 continuous treatment from the egg to the larval L4 stage and (2 discontinuous treatment in which L4 larvae were exposed for 30 h. Mosquitoes from two Brazilian cities were studied: São José do Rio Preto (SJ in São Paulo State and Goiânia (GO in Goiás State. According to criterions established by World Health Organization (WHO mosquitoes from SJ are organophosphate-susceptible while mosquitoes from GO are organophosphate-resistant. For both SJ and GO larvae the two different PB-treatments resulted in significantly increased tolerance (measured by reduced mortality to 0.01mg/L TE while for larvae exposed to 0.02 mg/L TE only continuous PB-treatment resulted in significantly increased TE-tolerance. The reduction of mortality rate was greater in SJ larvae than in GO larvae, confirming data from other organisms indicating that the effect of PB is more pronounced in susceptible strains. To test if oxidase enzymes were involved in PB-induced tolerance we treated PB-pretreated SJ and GO larvae with the oxidase inhibitor piperonyl butoxide (PBO before exposure to TE and observed increased (rather than decreased tolerance, suggesting that oxidases are not involved in the tolerance process and that PB and PBO can act in concert or synergistically. Esterase patterns of PB-pretreated larvae indicated that the cholinesterases EST-13 and EST-14 are involved in the PB-induced TE- tolerance, reinforcing a previous study carried out in our laboratory which suggested that increased esterase synthesis is the mechanism responsible for the development of insecticide resistance in Aedes aegypti.
and Green 1987:256). maculosa James and Liston. 19I 1. Rattanarithikul and Green 1987:256 (lectotype 9 desig.- BM). Subgenus Nyssorhynchus Blanchard...1990:39 (2 syntypes, BM). campiorhynchus (Thomson) annulipes Taylor, 1914. Townsend 1990:42 (?3 syntypes; BM). detritus (Haliday) maculosa Theobald, 1905...Skuse, 195 misionensis Duret. 199 macu/at us Theobald. 181 moenensis Iyengar, 2 10 maculosa James and Liston, 183 mojuensis Duret and Damasceno. 200
Francisco F. Ludueña Almeida
Full Text Available Aedes albifasciatus is a flood water mosquito ocurring in the southern countries of South America. It is a competent vector of the Western Equine Encephalitis (WEE and causes important losses on milk and beef production in central Argentina. Field work was carried out from December 1990 to March 1993, on a monthly basis during the dry season and biweekly during the rainy season. Larvae were collected using the 'dipping' technique and females with CDC traps baited with CO2. Field collected larvae were used to build laboratory cohorts, from which basic population parameters were estimated. Eggs survived up to six months on dry soil, although there was a linear decrease of viability with time. At 23ºC, larval development time was around nine days, and all adults emerged within one week. The estimation of larval development in the laboratory seems to be very near the development on the field, as larvae have been collected on average eight days after a rainfall. Egg to adult survival was 83%, with the highest mortality on fourth larval instar (6%. In the laboratory studies, sex proportion among the adults was 1:1, females lived longer than males (median 13 and five days, respectively, and adult survival pattern showed a constant number of individuals dying per unit time. Field collected females layed an average of 84 eggs per batch, and completing up to five gonotrophic cycles, suggesting an estimated survival of up to 35-50 days.
Blažejová, Hana; Šebesta, Oldřich; Rettich, František; Mendel, Jan; Čabanová, Viktória; Miterpáková, Martina; Betášová, Lenka; Peško, Juraj; Hubálek, Zdeněk; Kampen, Helge; Rudolf, Ivo
We report the distribution of mosquitoes of the maculipennis complex in two distinct areas of the Czech Republic (Bohemia and South Moravia) and in one locality of neighbouring Slovakia with emphasis on the detection of the newly described cryptic species Anopheles daciae (Linton, Nicolescu & Harbach, 2004). A total of 691 mosquitoes were analysed using a species-specific multiplex PCR assay to differentiate between the members of the maculipennis complex. In the Czech Republic, we found Anopheles maculipennis (with a prevalence rate of 1.4%), Anopheles messeae (49.0%) and Anopheles daciae (49.6%). In Slovakia, only An. messeae (52.1%) and An. daciae (47.9%) were detected. In this study, An. daciae was documented for the first time in the two countries where it represented a markedly higher proportion of maculipennis complex species (with an overall prevalence almost reaching 50%) in comparison to previous reports from Germany, Romania and Poland. The determination of the differential distribution of maculipennis complex species will contribute to assessing risks of mosquito-borne diseases such as malaria or dirofilariasis.
Davis, Timothy J; Kline, Daniel L; Kaufman, Phillip E
Aedes albopictus (Skuse) is a container-breeding mosquito commonly found in residential areas of its range in the United States. Mosquitoes are known to utilize flowering plants for sugar acquisition. Limited information is known about the influences on oviposition site selection, outside of container size. Residential areas are often landscaped with a variety of flowering plants and are known to provide numerous sizes of potential larval developmental sites for container-breeding mosqutioes. Through screened enclosure and field studies, the oviposition preference of Ae. albopictus for containers of three selected sizes (473, 946 and 1,892 ml) and the influence of flowering butterfly bush (Buddleja davidii Franchett cultivar 'Guinevere') plants were examined. Our results document that significantly more eggs were oviposited in the largest containers. Additionally, significantly more eggs were oviposited in containers adjacent to flowering butterfly bushes than in those without a flowering butterfly bush. Finally, our results document that flowering butterfly bushes exerted greater influence over Ae. albopictus oviposition decisions than did container size. Our findings can be applied to several aspects of Ae. albopictus surveillance and control.
termi- nalia and legs mounted; #NY 123-11 from Khaoyai. Five specimens came from Chiang Mai : #T-2195-10L and #T-2123-1P from Doi Sutep; #T-2413-lP...examined. The Thailand material contained 1 whole larva and 17 males with 9 associated larval and pupal skins from Chiang Mai ; 3 males, 2 with
genero Nyssorhynchus, corn especial referencia a morfologia dos ovos. Rev. Biol. Hyg. 9:51- 60. 1938b. Observacoes sobre o ciclo evolutivo de Anopheles...Vale do Paraiba. Nova variedade e ciclo evolutivo do Anofeles (Nyssorhynchus) osvaldoi var. ayrozai n. var. Ann. Paul. Med. Cir. 40:377-392. 1940b
Nyssorhynchus, corn especial referencia a morfologia dos ovos. Rev. Biol. Hyg. 9:51- 60. 1938b. Observacoes sobre o ciclo evolutivo de Anopheles oswaldoi...Anofelinos do Vale do Paraiba. Nova variedade e ciclo evolutivo do Anofeles (Nyssorhynchus) osvaldoi var. ayrozai n. var. Ann. Paul. Med. Cir. 40:377
signiÞcant disease and economic disruption. Rift Valley fever virus (RVFV), whichhasbeen responsible fornumerousoutbreaksof severe disease in ruminants and...is predominately a disease of domestic ruminants (cattle, goats, and sheep), where infection in pregnant animals usually results in abortion, and...www.cdc.gov/EID/ content /13/8/e1.htm). Britch, S.C.,K. J.Linthicum,A.Anyamba,C. J.Tucker,E.W. Pak, F. A. Maloney, K. Cobb, E. Stanwix, J. Humphries, A
Little, E; Biehler, D; Leisnham, P T; Jordan, R; Wilson, S; LaDeau, S L
Social, ecological, and climatic factors interact creating a heterogeneous matrix that determines the spatiotemporal distribution of mosquitoes and human risks of exposure to the diseases they transmit. We explore linkages between the social and institutional processes behind residential abandonment, urban ecology, and the interactions of socio-ecological processes with abiotic drivers of mosquito production. Specifically, we test the relative roles of infrastructure degradation and vegetation for explaining the presence of Aedes albopictus Skuse 1894 to better predict spatial heterogeneity in mosquito exposure risk within urban environments. We further examine how precipitation interacts with these socially underpinned biophysical variables. We use a hierarchical statistical modeling approach to assess how environmental and climatic conditions over 3 years influence mosquito ecology across a socioeconomic gradient in Baltimore, MD. We show that decaying infrastructure and vegetation are important determinants of Ae. albopictus infestation. We demonstrate that both precipitation and vegetation influence mosquito production in ways that are mediated by the level of infrastructural decay on a given block. Mosquitoes were more common on blocks with greater abandonment, but when precipitation was low, mosquitoes were more likely to be found in higher-income neighborhoods with managed container habitat. Likewise, although increased vegetation was a negative predictor of mosquito infestation, more vegetation on blocks with high abandonment was associated with the largest mosquito populations. These findings indicate that fine spatial scale modeling of mosquito habitat within urban areas is needed to more accurately target vector control. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
clans specimens in the Del -Mar-Va Peninsula (Buescher et al. J-920). The sig- nificance of these arbovirus isolations is discussed later. SYSTEMATIC...34EAH45", 5-VIII-1972, Rogers, 1L (UCLA), Belize: Sierra de Agua , IV-T.946, A. J. Walker, 29 (IJCLA). "BHA138", 1967, Mosq. Mid. Amer. 19 (UCLA), "BH366...highly acid Alabama swamp. The water had a high concentration of sulfate, sodium, potassium and ferrous ions as a result of contamination by a
Almirón Walter R.
Full Text Available Con el propósito de estudiar la preferencia de hospedadores vertebrados por mosquitos hembras, durante 2 períodos octubre-abril (primavera-verano, se realizaron muestreos cada 15 días en Córdoba y Cosquín (Argentina. Se utilizaron trampas de latón con cebo animal: anfibios (sapos, aves (pollos, mamíferos (conejos y reptiles (tortugas. El 92,9% de los especímenes recolectados pertenecen al género Culex, mientras que un 7,0% corresponde a Aedes y el 0,02% restante a Psorophora ciliata, única especie que se capturó de ese género. En trampas con pollo se recolectó el mayor número de hembras (68,7%, siguiendo en orden las trampas con conejos (29,9%, con tortugas (0,8% y con sapos (0,5%, por lo tanto, la mayoría de los mosquitos entraron en las trampas con hospedadores homeotermos. Culex dolosus se alimentó sobre todos los cebos, mientras que Cx. acharistus, Cx. chidesteri y Cx. quinquefasciatus se alimentaron sobre pollos, conejos y tortugas; Ae. albifasciatus, Ae. scapularis, Cx. bidens y Cx. coronator lo hicieron sobre ambos hospedadores homeotermos; Cx. apicinus, Cx. maxi, Cx. saltanensis y Cx. spinosus se alimentaron solamente sobre pollos y Ps. ciliata sobre conejos.
Miguel Alfonso Pacheco
Conclusions. We registered 11 new wing spot patterns in the costal vein and the dominance of the patterns I and VI for populations of An. darlingi from Colombia. We confirmed DSIII2/TaIII2 ratio as a robust diagnostic character for the taxonomy of this species. We found differences between the size and shape of the wings of An. darlingi populations in accordance to their geographical distribution, which constitute important bionomic aspects for this malaria vector.
Ondiaka, S.N.; Masinde, E.W.; Koenraadt, C.J.M.; Takken, W.; Mukabana, W.R.
Background The entomopathogenic fungus Metarhizium anisopliae shows great promise for the control of adult malaria vectors. A promising strategy for infection of mosquitoes is supplying the fungus at plant feeding sites. Methods We evaluated the survival of fungus-exposed Anopheles gambiae
The potential for gut microbiota to impede or enhance pathogen transmission is well-documented but the factors that shape this microbiota in mosquito vectors are poorly understood. We characterized and compared the gut microbiota of adult females of Culex restuans Theobald from different parents. Cu...
Pimenta Paulo FP
Full Text Available Abstract Background The insect gut harbors a variety of microorganisms that probably exceed the number of cells in insects themselves. These microorganisms can live and multiply in the insect, contributing to digestion, nutrition, and development of their host. Recent studies have shown that midgut bacteria appear to strengthen the mosquito's immune system and indirectly enhance protection from invading pathogens. Nevertheless, the physiological significance of these bacteria for mosquitoes has not been established to date. In this study, oral administration of antibiotics was employed in order to examine the contribution of gut bacteria to blood digestion and fecundity in Aedes aegypti. Results The antibiotics carbenicillin, tetracycline, spectinomycin, gentamycin and kanamycin, were individually offered to female mosquitoes. Treatment of female mosquitoes with antibiotics affected the lysis of red blood cells (RBCs, retarded the digestion of blood proteins and reduced egg production. In addition, antibiotics did not affect the survival of mosquitoes. Mosquito fertility was restored in the second gonotrophic cycle after suspension of the antibiotic treatment, showing that the negative effects of antibiotics in blood digestion and egg production in the first gonotrophic cycle were reversible. Conclusions The reduction of bacteria affected RBC lysis, subsequently retarded protein digestion, deprived mosquito from essential nutrients and, finally, oocyte maturation was affected, resulting in the production of fewer viable eggs. These results indicate that Ae. aegypti and its midgut bacteria work in synergism to digest a blood meal. Our findings open new possibilities to investigate Ae. aegypti-associated bacteria as targets for mosquito control strategies.
Mosquitoes of medical importance. U.S. Dep. Agric. Agric. Handb. 152. Forattini, O.P. 1962. Entomologia medica vol. I. Faculdade de Higiene e Saude Publica...meridional do Brasil. Rev. Saude Publ., S. Paulo. 21: 291-304. Forattini, O.P. 1962. Entomologia medica vol. I. Faculdade de Higiene e Saude...152. Forattini, O.P. 1962. Entomologia medica vol. I. Faculdade de Higiene e Saude Publica, Sao Paulo, Brazil. 662 pp. Grieco, J.P. 2001. The
Shah, Rizwan Mustafa; Ali, Qasim; Alam, Mehboob; Shad, Sarfraz Ali; Majeed, Shahid; Riaz, Muhammad; Binyameen, Muhammad
Culex quinquefasciatus Say is an important disease vector throughout much of the world. Experiments were conducted to determine the effects of different larval habitat substrates on the fitness and biting efficiency of Cx. quinquefasciatus adults. Our findings indicate that the development time (egg to adult) of larvae reared in irrigation water was 8.63 d while that of larvae reared in distilled water was 17.10 d (Effect size = 0.95). However, the rate of adult emergence was similar for all the tested treatments. Furthermore, the mean weight of an egg raft varied between larval habitats: distilled water (1.83 mg), rainfall water (1.25 mg), irrigation water (1.52 mg), and sewerage water (2.52 mg) (Effect size = 0.91). But, the fecundity (eggs per female) and hatchability (%) were statistically similar in all the rearing mediums (Effect size = 0.79). Longevity of females in all the tested populations did not differ significantly (Effect size = 0.91). The mean relative growth rates of larvae reared in tap water (0.80) and distilled water (0.86) habitats were lower than growth rates in all other rearing habitats (Effect size = 0.96). The intrinsic rate of natural increase in tap water (0.27) and irrigation water (0.35) was significantly higher than that in distilled water (0.09) and sewerage water (0.16) (Effect size = 0.84). Adults reared in rain water had the highest biting efficiency among all the tested populations. These results provide useful information for the management of Cx. quinquefasciatus. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Chitolina, R F; Anjos, F A; Lima, T S; Castro, E A; Costa-Ribeiro, M C V
The selection of oviposition sites by females of Aedes (Stegomyia) aegypti is a key factor for the larval survival and egg dispersion and has a direct influence in vector control programs. In this study, we evaluated the aspects of reproductive physiology of Ae. aegypti mosquitoes tested in the presence of raw sewage. Ae. aegypti females were used in oviposition bioassays according to two methodologies: (i) choice assay, in which three oviposition substrates were offered in the same cage: treatment (raw sewage), positive control (distilled water) and negative control (1% sodium hypochlorite) and; (ii) no choice assay, in which only one substrate was available. The physicochemical and microbiological analysis of the raw sewage used in this study indicated virtually no levels of chlorine, low levels of dissolved oxygen and high levels of nitrogenous compounds as well as the presence of Escherichia coli and total fecal coliforms. After 72h of oviposition, the eggs were counted and there was no statistically significant difference (p>0.05) in the oviposition rate between raw sewage and positive control in both methodologies. In addition, females were dissected to evaluate egg-retention and also there were no appreciable differences in egg retention even when raw sewage was the only substrate offered. The data also showed that egg hatching and larvae development occurred normally in the raw sewage. Therefore, the present study suggests that Ae. aegypti can adapt to new sites and lay eggs in polluted water, such as the raw sewage. These findings are of particular importance for the control and surveillance programs against Ae. aegypti in countries where the conditions of poor infrastructure and lack of basic sanitation are still an issue. Copyright © 2016 Elsevier B.V. All rights reserved.
Full Text Available Objective: To determine the adulticidal activity of hexane, benzene, chloroform, ethyl acetate and methanol leaf and seed extracts of Delonix elata (D. elata against Aedes aegypti (Ae. aegypti. Methods: The bioassay was conducted in an experimental kit consisting of two cylindrical plastic tubes both measuring 125 mm×44 mm following the WHO method; mortality of the mosquitoes was recorded after 24 h. Results: The adulticidal activity of plant leaf and seed extracts showed moderate toxic effect on the adult mosquitoes after 24 h of exposure period. However, the highest adulticidal activity was observed in the leaf methanol extract of D. elata against Ae. aegypti with the LC50 and LC90 values 162.87 and 309.32 mg/L, respectively. Conclusions: From this result, it can be concluded the crude extract of D. elata was an excellent potential for controlling Ae. aegypti mosquitoes.
Full Text Available Many environmental factors, biotic and abiotic interact to influence organismal development. Given the importance of Aedes aegypti as a vector of human pathogens including dengue and yellow fever, understanding the impact of environmental factors such as temperature, resource availability, and intraspecific competition during development is critical for population control purposes. Despite known associations between developmental traits and factors of diet and density, temperature has been considered the primary driver of development rate and survival. To determine the relative importance of these critical factors, wide gradients of conditions must be considered. We hypothesize that 1 diet and density, as well as temperature influence the variation in development rate and survival, 2 that these factors interact, and this interaction is also necessary to understand variation in developmental traits. Temperature, diet, density, and their two-way interactions are significant factors in explaining development rate variation of the larval stages of Ae. aegypti mosquitoes. These factors as well as two and three-way interactions are significantly associated with the development rate from hatch to emergence. Temperature, but not diet or density, significantly impacted juvenile mortality. Development time was heteroskedastic with the highest variation occurring at the extremes of diet and density conditions. All three factors significantly impacted survival curves of experimental larvae that died during development. Complex interactions may contribute to variation in development rate. To better predict variation in development rate and survival in Ae. aegypti, factors of resource availability and intraspecific density must be considered in addition, but never to the exclusion of temperature.
Full Text Available Background: Application of plant extracts as mosquito control strategy was practiced from centuries. These are easily available, non-toxic, biodegradable and exhibit broad-spectrum target specific activities against larval stages of mosquitoes.Method: Different potential parts of locally grown plants, seeds of nutmeg (Myristica fragrans, peel of musambi (Citrus sinensis, leaves of babuna (Matricaria chamomilla, mint (Mentha spicata and ginger rhizome (Zingiber officinale selected and evaluated for their larvicidal properties against Aedes (Stegomyis albopictus. Oils were extracted through steam distillation process and extracts were evaluated as per WHO 2005 guidelines for testing of insecticides against larvae of mosquitoes.Result: Among the five plant extracts, C. sinensis had the lowest LC50 (400.81ppm while M. fragrans had the highest LC50 value (710.30ppm respectively after 24h of exposure. In terms of % age mortality, a series of concentrations (300–800ppm gave high % mortality in case of C. sinensis while M. fragrans gave low % age mortality.Conclusion: All the five plant species have larvicidal effects to certain extant and C. sinensis had great potential. Further small-scale field trials with the extracts of the most promising one (C. sinensis shall be conducted to determine operational feasibility.
Soltani, Aboozar; Vatandoost, Hassan; Oshaghi, Mohammad Ali; Enayati, Ahmad Ali; Chavshin, Ali Reza
In the current study, the effects of the presence of symbiotic bacteria on the activity of the enzymes involved in An. stephensi resistance to temephos are evaluated for the first time. Four different strains (I. susceptible strain, II. resistant strain, III. resistant strain + antibiotic, and IV. resistant strain + bacteria) were considered in order to determine the possible effects of the symbiotic bacteria on their hosts' resistance to temephos. The median values of all enzymes of susceptible strain were compared with those of other resistant strains. The results of this study indicated a direct relationship between the presence of bacteria in the symbiotic organs of An. stephensi and resistance to temephos. The profile of enzymatic activities in the resistant strain changed to a susceptible status after adding antibiotic. The resistance of An. stephensi to temephos could be completely broken artificially by removing their bacterial symbionts in a resistant population.
Marcial Corrêa Cárcamo
Full Text Available Abstract: INTRODUCTION: We report the larvicidal activity of two formulations from Amanita muscariaagainst Culex quinquefasciatus, as well as the viability of the aqueous extract after storage. METHODS The larvicidal activity of aqueous extract and powder from A. muscaria, and the viability of the aqueous extract after storage, were evaluated. RESULTS The aqueous extract caused larval deaths, which varied from 16.4% to 88.4%. The efficiency of the powder varied from 29.2% to 82.8%. Storage did not interfere with the larvicidal efficiency of the aqueous extract of A. muscaria. CONCLUSIONS These results show the potential of A. muscariato control C. quinquefasciatus.
Honorio, Nildimar A. [Instituto Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ (Brazil). Dept. de Entomologia. Lab. de Transmissores de Hematozoarios; Barros, Fabio S.M. de [Universidade Federal de Roraima (UFRR), Boa Vista, RR (Brazil). Centro de Ciencias Biologicas e da Saude. Nucleo Avancado de Vetores; Tsouris, Pantelis; Rosa-Freitas, Maria G. [Freitas and Tsouris Consultants, Spata-Attikis (Greece)]. E-mail: email@example.com
Toxorhynchites guadeloupensis (Dyar and Knab), a poorly known mosquito species, was observed preying upon Aedes aegypti (L.) larvae, in an oviposition trap placed for routine dengue entomological surveillance, during 2003-2004 in the urban area of Boa Vista, Roraima, Brazil. This is the first report for Tx. guadeloupensis using Ae. aegypti oviposition traps as breeding places. This finding may have important consequences in the epidemiology and local dengue control since Ae. aegypti density is a basic variable in dengue prediction. Whether predation of Ae aegypti by Tx. guadeloupensis in the Amazon is of significance, is a question to be examined. Also, larval predation may be a cause for underestimation of the actual Ae aegypti numbers. Together these hypotheses need to be better investigated as they are directly related to dengue epidemiology, to the success of any outbreak prediction and surveillance program. (author)
Turell, Michael J; Dohm, David J; Sardelis, Michael R; O 'Guinn, Monica L; Andreadis, Theodore G; Blow, Jamie A
.... To develop appropriate surveillance and control strategies, the identification of which mosquito species are competent vectors and how various factors influence their ability to transmit this virus must be determined...
species , but see Bourke et al . Genealogical analyses of complete mtDNA COI (Cyto- chrome oxidase I) sequences found that A. marajoara is...darlingi in human malaria transmission in Boa Vista, state of Roraima, Brazil. Mem Inst Oswaldo Cruz 2006, 101:163-168. 17. Bourke BP, Foster PG
Ngoagouni, Carine; Kamgang, Basile; Nakoun?, Emmanuel; Paupy, Chistophe; Kazanji, Mirdad
Aedes albopictus, a mosquito native to Asia, has invaded all five continents during the past three decades. It was reported in central Africa in the 2000s, first in Cameroon, and, since then, has colonised almost all countries of the region. The species, originally considered a secondary vector of dengue viruses, has been showed to play a major role in transmission of chikungunya virus in numerous countries, including in the central African region. We review the current spread of Ae. albopict...
Ngoagouni, Carine; Kamgang, Basile; Nakouné, Emmanuel; Paupy, Chistophe; Kazanji, Mirdad
Aedes albopictus, a mosquito native to Asia, has invaded all five continents during the past three decades. It was reported in central Africa in the 2000s, first in Cameroon, and, since then, has colonised almost all countries of the region. The species, originally considered a secondary vector of dengue viruses, has been showed to play a major role in transmission of chikungunya virus in numerous countries, including in the central African region. We review the current spread of Ae. albopictus in central Africa, its larval ecology and its impact on indigenous species such as Ae. aegypti. We explore the potential of Ae. albopictus to affect the epidemiology of emerging or re-emerging arboviruses and discuss the conventional means for its control, while emphasizing the importance of data on its susceptibility to insecticides to cope with potential outbreaks.
Hugo Costa Osório
Full Text Available The Asian tiger mosquito Aedes albopictus is an invasive mosquito originating from the Asia-Pacific region. This species is of major concern to public and veterinary health because of its vector role in the transmission of several pathogens, such as chikungunya, dengue, and Zika viruses. In Portugal, a National Vector Surveillance Network (REde de VIgilância de VEctores—REVIVE is responsible for the surveillance of autochthonous, but also invasive, mosquito species at points of entry, such as airports, ports, storage areas, and specific border regions with Spain. At these locations, networks of mosquito traps are set and maintained under surveillance throughout the year. In September 2017, Ae. albopictus was detected for the first time in a tyre company located in the North of Portugal. Molecular typing was performed, and a preliminary phylogenetic analysis indicated a high similarity with sequences of Ae. albopictus collected in Europe. A prompt surveillance response was locally implemented to determine its dispersal and abundance, and adult mosquitoes were screened for the presence of arboviral RNA. A total of 103 specimens, 52 immatures and 51 adults, were collected. No pathogenic viruses were detected. Despite the obtained results suggest low abundance of the population locally introduced, the risk of dispersal and potential establishment of Ae. albopictus in Portugal has raised concern for autochthonous mosquito-borne disease outbreaks.
Full Text Available Mosquitoes are vectors of several human pathogens, and great attention has recently been placed on insecticides from plant-derived products, in search for mosquito control agents. This study, thus, investigated the potency of Boswellia dalzielii methanol leaf extract and its four fractions as mosquito ovicide, larvicide, and pupicide against Anopheles gambiae and Culex quinquefasciatus . The plant products were tested at the following concentrations: 125, 250, 500, 1000, and 2000 ppm on eggs and 312.5, 625, 1250, and 2500 ppm on the larvae and pupae of the mosquitoes. For results, hatchability of A. gambiae eggs was reduced to 5% with n -hexane fraction at 2000 ppm. Among the plant products tested, n -hexane fraction was most toxic against A. gambiae (LC 50 = 385.9 ppm and C. quinquefasciatus (LC 50 = 3394.9 ppm. The n -hexane fraction of B. dalzielii might be used as a mosquitocidal agent in the breeding sites of A. gambiae and C. quinquefasciatus .
Maria Torres Olave
Full Text Available The mosquitoes distribution and the presence of arboviruses are determined by temperature, rainfall, geographic barriers, and other factors that determine the distribution of Culex spp. and can influence the human arboviral. The objective of this study was to identify potential spatial distribution of Culex spp. The ecological niche modeling was performed using MaxEnt Ecological niche modeling was performed using MaxEnt, bioclimatic variables (WorldClim used for this process are derived from the monthly values of temperature and precipitation to generate biologically significant variables (representing annual trends and limiting factors for the distribution of species. The resulting maps can be interpreted as relative suitability areas, these areas are presented on the east coast of Mexico, mainly in the states of Veracruz and Tabasco. The results show that Bio 2 (mean monthly temperature range, Bio 7 (annual range of temperature and Bio 11 (mean temperature of the coldest quarter, determine the highest percentage range. Distribution modeling Culex spp. It is an approach to identify the most vulnerable areas in Mexico. It is necessary to strengthen and establish multidisciplinary programs for the prevention ofCulexspp transmitted diseases.
1986. However, there have been few laboratory studies Container Volume. Eggs of Tx. amboinensis of the phenomenon. Rubio & Avesta (1984) sug- were...predator ratio and frequency of cannibalism, as competition for food may limit growth. Alterna- proposed by Rubio & Avesta (1984). A careful ex- tively, the
Heringer, Laila; Johnson, Brian J; Fikrig, Kara; Oliveira, Bruna A; Silva, Richard D; Townsend, Michael; Barrera, Roberto; Eiras, Álvaro E; Ritchie, Scott A
The Gravid Aedes Trap (GAT) uses visual and olfactory cues to attract gravid Aedes aegypti (L.) that are then captured when knocked down by a residual pyrethroid surface spray. However, the use of surface sprays can be compromised by poor availability of the spray and pesticide resistance in the target mosquito. We investigated several "alternative" insecticide and insecticide-free killing agents for use in the GAT. This included long-lasting insecticide-impregnated nets (LLINs), vapor-active synthetic pyrethroids (metofluthrin), canola oil, and two types of dry adhesive sticky card. During bench top assays LLINs, metofluthrin, and dry sticky cards had 24-h knockdown (KD) percentages >80% (91.2 ± 7.2%, 84.2 ± 6.8%, and 83.4 ± 6.1%, respectively), whereas the 24-h KD for canola oil was 70 ± 7.7%, which improved to 90.0 ± 3.7% over 48 h. Importantly, there were no significant differences in the number of Ae. aegypti collected per week or the number of traps positive for Ae. aegypti between the sticky card and canola oil treatments compared with the surface spray and LLIN treatments in semifield and field trials. These results demonstrate that the use of inexpensive and widely available insecticide-free agents such as those described in this study are effective alternatives to pyrethroids in regions with insecticide-resistant populations. The use of such environmentally friendly insecticide-free alternatives will also be attractive in areas where there is substantial resistance to insecticide use due to environmental and public health concerns. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Chin, A C; Chen, C D; Low, V L; Lee, H L; Azidah, A A; Lau, K W; Sofian-Azirun, M
This study was conducted using the glass chamber method to determine the susceptibility status of the dengue vector, Aedes aegypti (L.) from 11 states in Malaysia to commercial mosquito coils containing four different active ingredients, namely metofluthrin, d-allethrin, d-trans allethrin, and prallethrin. Aedes aegypti exhibited various knockdown rates, ranging from 14.44% to 100.00%, 0.00% to 61.67%, 0.00% to 90.00%, and 0.00% to 13.33% for metofluthrin, d-allethrin, d-trans allethrin, and prallethrin, respectively. Overall, mortality rates ranging from 0.00% to 78.33% were also observed among all populations. Additionally, significant associations were detected between the knockdown rates of metofluthrin and d-allethrin, and between metofluthrin and d-trans allethrin, suggesting the occurrence of cross-resistance within pyrethroid insecticides. Overall, this study revealed low insecticidal activity of mosquito coils against Ae. aegypti populations in Malaysia, and consequently may provide minimal personal protection against mosquito bites. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
Juan C. Santana-Martínez
Full Text Available Aedes aegypti and Culex quinquefasciatus are mosquito vectors for several tropical diseases that represent a current public health problem. The ecological requirements for each species are different, however, both species show high biological adaptability, which promotes their coexistence in the same breeding sites. The purpose of this study was to assess the effect of larval association between Ae. aegypti and Cx. quinquefasciatus under different laboratory conditions of food supply and temperature, and under field simulated conditions like peridomestic containers. Our findings showed that under field simulated conditions there was no asymmetrical competition in mixed cultures with the different Cx. quinquefasciatus/Ae. aegypti ratios tested. However, under laboratory conditions in which different doses of food supply were evaluated, it was observed that competition between the two species takes place. Larval coexistence under food scarcity conditions (0.95 mg/larva showed that Ae. aegypti had a greater adult emergence than Cx. quinquefasciatus and was capable of depriving Cx. quinquefasciatus of the food needed to complete metamorphosis. In an intermediate dose of food (1.9 mg/larva, the dry weight of Cx. quinquefasciatus adults decreased, and their larval development time increased when Cx. quinquefasciatus/Ae. aegypti ratio was low. Also, a temperature effect was assessed demonstrating that Cx. quinquefasciatus was more vulnerable to changes in temperature. We suggest that Ae. aegypti is more successful in exploiting microhabitats when food is scarce, due to its scrape active feeding habitats and fast larval development times. Therefore, in conditions of food paucity both species will compete, and Ae. aegypti larvae will prevail.
Fang, Yuan; Shi, Wen-Qi; Zhang, Yi
The Anopheles hyrcanus group, which includes at least 25 species, is widely distributed in the Oriental and Palearctic regions. Some group members have been incriminated as vectors of malaria and other mosquito-borne diseases. It is difficult to identify Hyrcanus Group members by morphological features. Thus, molecular phylogeny has been proposed as an important complementary method to traditional morphological taxonomy. Based on the GenBank database and our original study data, we used 466 mitochondrial DNA COI sequences belonging to 18 species to reconstruct the molecular phylogeny of the Hyrcanus Group across its worldwide geographic range. The results are as follows. 1) The average conspecific K2P divergence was 0.008 (range 0.002-0.017), whereas sequence divergence between congroup species averaged 0.064 (range 0.026-0.108). 2) The topology of COI tree of the Hyrcanus Group was generally consistent with classical morphological taxonomy in terms of species classification, but disagreed in subgroup division. In the COI tree, the group was divided into at least three main clusters. The first cluster contained An. nimpe; the second was composed of the Nigerrimus Subgroup and An. argyropus; and the third cluster was comprised of the Lesteri Subgroup and other unassociated species. 3) Phylogenetic analysis of COI indicated that ancient hybridizations probably occurred among the three closely related species, An. sinensis, An. belenrae, and An. kleini. 4) The results supported An. paraliae as a probable synonym of An. lesteri, and it was possible that An. pseudopictus and An. hyrcanus were the same species, as evident from their extremely low interspecific genetic divergence (0.020 and 0.007, respectively) and their phylogenetic positions. In summary, we reconstructed the molecular phylogeny and analysed genetic divergence of the Hyrcanus Group using mitochondrial COI sequences. Our results suggest that in the future of malaria surveillance, we should not only pay much attention to those known vectors of malaria, but also their closely related species.
Faraj, C; Ouahabi, S; Adlaoui, E; Elaouad, R
This bibliographical study, based on published works, ministry of Health Reports, exploitation of the database relative to the entomological surveillance conducted in the framework of the National Malaria Control Program, as well as unpublished results obtained within the framework of the European project "Emerging disease in a changing European environment", summarizes and completes with new data current knowledge on the systematics, the distribution and the vectorial competence of moroccan anophelines. Copyright © 2010 Elsevier Masson SAS. All rights reserved.
Azubuike C. Ukubuiwe
Full Text Available The need to have an improved knowledge on the bioecology of Culex quinquefasciatus , a prerequisite in the development of cost-effective control strategies, has informed the present preliminary investigation to put in better perspective variations that exist in the egg rafts of the species. Freshly laid egg rafts were collected and incubated at ambient temperature in well-labeled plastic trays. The results showed overall inconsistency in all indices monitored for the egg rafts. Generally, survivorship was high for the species. All immature stage and adult parameters measured varied significantly among the egg rafts and between/within sexes of the species. Therefore, this study suggests the presence of inherent variation in the bionomics of egg rafts of C. quinquefasciatus , probably influenced by the environment and hence underscores the need for additional studies to further elucidate the roles of genetics and environment in vectorial competence of the species, in order to develop robust sustainable mosquito vector control protocols.
Wu, Tai-Ping; Tian, Jun-Hua; Xue, Rui-De; Fang, Yi-Liang; Zheng, Ai-Hua
In 2014, Guangzhou City, South China, suffered from its worst outbreak of dengue fever in decades. Larval mosquito habitat surveillance was carried out by using android mobile devices in four study sites in May 2015. The habitats with larval mosquitoes were recorded as photo waypoints in OruxMaps or in videos. The total number of potential mosquito habitats was 342, of which 166 (49%) were found to have mosquito larvae or pupae. Small containers were the most abundant potential habitats, accounting for 26% of the total number. More mosquito larvae and pupae, were found in small containers than in other objects holding water, for example, potted or hydroponic plants ( p Android mobile devices are a convenient and useful tool for surveillance of mosquito habitats, and the enhancement of source reduction may benefit the prevention and control of dengue vector mosquitoes.
Muturi, Ephantus J; Ramirez, Jose L; Doll, Kenneth M; Bowman, Michael J
Essential oils are potential alternatives to synthetic insecticides because they have low mammalian toxicity, degrade rapidly in the environment, and possess complex mixtures of bioactive constituents with multi-modal activity against the target insect populations. Twenty-one essential oils were initially screened for their toxicity against Aedes aegypti (L.) larvae and three out of the seven most toxic essential oils (Manuka, oregano, and clove bud essential oils) were examined for their chemical composition and combined toxicity against Ae. aegypti larvae. Manuka essential oil interacted synergistically with oregano essential oil and antagonistically with clove bud essential oil. GC-MS analysis revealed the presence of 21 components in Manuka essential oil and three components each in oregano and clove bud essential oils. Eugenol (84.9%) and eugenol acetate (9.6%) were the principal constituents in clove bud essential oil while carvacrol (75.8%) and m-isopropyltoluene (15.5%) were the major constituents in oregano essential oil. The major constituents in Manuka essential oil were calamenene (20%) and 3-dodecyl-furandione (11.4%). Manuka essential oil interacted synergistically with eugenol acetate and antagonistically with eugenol, suggesting that eugenol was a major contributor to the antagonistic interaction between Manuka and clove bud essential oils. In addition, Manuka interacted synergistically with carvacrol suggesting its contribution to the synergistic interaction between Manuka and oregano essential oils. These findings provide novel insights that can be used to develop new and safer alternatives to synthetic insecticides. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.
Gnankiné, Olivier; Bassolé, Imaël Henri Nestor
Widespread resistance of Anopheles sp. populations to pyrethroid insecticides has led to the search for sustainable alternatives in the plant kingdom. Among many botanicals, there is great interest in essential oils and their constituents. Many researchers have explored essential oils (EOs) to determine their toxicity and identify repellent molecules that are effective against Anopheles populations. Essential oils are volatile and fragrant substances with an oily consistency typically produced by plants. They contain a variety of volatile molecules such as terpenes and terpenoids, phenol-derived aromatic components and aliphatic components at quite different concentrations with a significant insecticide potential, essentially as ovicidal, larvicidal, adulticidal, repellency, antifeedant, growth and reproduction inhibitors. The current review provides a summary of chemical composition of EOs, their toxicity at different developmental stages (eggs, larvae and adults), their repellent effects against Anopheles populations, for which there is little information available until now. An overview of antagonist and synergistic phenomena between secondary metabolites, the mode of action as well as microencapsulation technologies are also given in this review. Finally, the potential use of EOs as an alternative to current insecticides has been discussed.
Full Text Available The purpose of the present study was to evaluate the larvicidal activity of leaf fractions of Annona senegalensis and Boswellia dalzielii against fourth instar larvae of Aedes aegypti. Fourth instar larvae of Ae. aegypti were exposed for 24 hours to various concentrations (312.5-2500 mg/L of methanolic crude extract and its fractions obtained with n-hexane, chloroform, ethyl-acetate and methanol solvents, following WHO method. The mortalities recorded were subjected to ANOVA test for mean comparison and Probit analysis to determine LC50. Preliminary phytochemical screening test for some components of the plants assessed were also evaluated. The phytochemical screening of the two plants revealed the presence of alkaloids, steroids, phenolic compounds, terpenoids, fats and oils in the crude extracts which, after splitting were most distributed in n-hexane and chloroform fractions. Apart from methanol fraction, all products used showed a significant (P<0.001 concentration-dependent toxicity against Ae. aegypti larvae. The LC50 recorded with crude extract were 759.6 and 830.4 mg/L for A. senegalensis and B. dalzielli respectively. After fractionation, n-hexane and chloroform fractions of A. senegalensis revealed more effective activity than others with CL50 values of 379.3 and 595.2 mg/L respectively. As for B. dalzielli, n-hexane (LC50=537.1 mg/L and chloroform (LC50=585.5 mg/L fractions were also the most effective. These results suggest that the n-hexane and chloroform fractions of these plants as a promising larvicide against Ae. aegypti and can constitute the best basic and vital step in the development of a botanical insecticide source.
specimens. bRange (Mode). TNTC-Too numerous to count. Table 3. Number of branches for setae of the fourth-instar larva of Aedes (Finlaya...2) 1,2(l) 1,2(2) 1,2(l) 1 2-4(2) 2,3(2) 7-ll(7) 1 1 1,2(l) aBased on counts from at least 10 setae on the holotype and 8 other specimens. bRange
Conn, Jan E.; Moreno, Marta; Saavedra, Marlon; Bickersmith, Sara A.; Knoll, Elisabeth; Fernandez, Roberto; Vera, Hubert; Burrus, Roxanne G.; Lescano, Andres G.; Sanchez, Juan Francisco; Rivera, Esteban; Vinetz, Joseph M.
Anopheline specimens were collected in 2011 by human landing catch, Shannon and CDC traps from the malaria endemic localities of Santa Rosa and San Pedro in Madre de Dios Department, Peru. Most specimens were either Anopheles (Nyssorhynchus) benarrochi B or An. (Nys.) rangeli, confirmed by polymerase chain reaction-restriction fragment length polymorphism-internal transcribed spacer 2 (PCR-RFLP-ITS2) and, for selected individuals, ITS2 sequences. A few specimens from Lupuna, Loreto Department, northern Amazonian Peru, were also identified as An. benarrochi B. A statistical parsimony network using ITS2 sequences confirmed that all Peruvian An. benarrochi B analyzed were identical to those in GenBank from Putumayo, southern Colombia. Sequences of the mtDNA COI BOLD region of specimens from all three Peruvian localities were connected using a statistical parsimony network, although there were multiple mutation steps between northern and southern Peruvian sequences. A Bayesian inference of concatenated Peruvian sequences of ITS2+COI detected a single clade with very high support for all An. benarrochi B except one individual from Lupuna that was excluded. No samples were positive for Plasmodium by CytB-PCR. PMID:23243107
Smithsonian Institution, Washington, DC 20560. ’ Ndcleo de Pesquisa Taxon6mica e Sistematica em Entomologia MBdica (NUPTEM), Departamento de Epidemiologia...anofelinos das regioes nordestinas e amazonica do Brasil. Rev. Serv. Esp. I: 827-965. Forattini, 0. P. 1962. Entomologia medica. vol. I. Parte Geral
Cetin, H; Yanikoglu, A; Cilek, J E
The mosquito Culex pipiens L. is an important pest in urban and suburban areas in many parts of the world. Septic tanks are the most important habitats supporting the production of this species in the city of Antalya, southwestern Turkey. Diflubenzuron, in a 25% wettable powder (Du-dim 25 WP), and a 4% granular formulation (Du-dim 4 G) was evaluated against late 2nd to early 3rd instars of Cx. pipiens in single-family septic tanks. Both formulations were tested at 0.01, 0.02, and 0.03 mg (AI)/liter. The results indicated that both formulations applied at the rate of 0.02 and 0.03 mg (AI)/liter achieved 100% adult inhibition, at intervals of 7, 14, 21, and 28 days after treatment. Septic tanks treated with 0.01 mg (AI)/liter WP formulation resulted in complete (100%) adult inhibition through 14 days, whereas the G formulation gave the same effect through 21 days posttreatment at this rate.
Christin, M.S.; Menard, L.; Gendron, A.D.; Ruby, S.; Cyr, D.; Marcogliese, D.J.; Rollins-Smith, L.; Fournier, M.
Over the last 30 years, there have been mass declines in diverse geographic locations among amphibian populations. Multiple causes have been suggested to explain this decline. Among these, environmental pollution is gaining attention. Indeed, some chemicals of environmental concern are known to alter the immune system. Given that amphibians are frequently exposed to agricultural pesticides, it is possible that these pollutants alter their immune system and render them more susceptible to different pathogens. In this study, we exposed two frog species, Xenopus laevis and Rana pipiens, for a short period of time to a mixture of pesticides (atrazine, metribuzine, endosulfan, lindane, aldicarb and dieldrin) representative in terms of composition and concentrations to what it is found in the environment of the southwest region of the province of Quebec. The pesticides were known to be present in surface water of many tributaries of the St. Lawrence River (Quebec, Canada). Our results demonstrate that the mixture of pesticides could alter the cellularity and phagocytic activity of X. laevis and the lymphocyte proliferation of R. pipiens. Taken together, these results indicate that agricultural pesticides can alter some aspects of the immune response in frogs and could contribute to their global decline by rendering them more susceptible to certain infections
Christin, M.S.; Menard, L.; Gendron, A.D.; Ruby, S.; Cyr, D.; Marcogliese, D.J.; Rollins-Smith, L.; Fournier, M
Over the last 30 years, there have been mass declines in diverse geographic locations among amphibian populations. Multiple causes have been suggested to explain this decline. Among these, environmental pollution is gaining attention. Indeed, some chemicals of environmental concern are known to alter the immune system. Given that amphibians are frequently exposed to agricultural pesticides, it is possible that these pollutants alter their immune system and render them more susceptible to different pathogens. In this study, we exposed two frog species, Xenopus laevis and Rana pipiens, for a short period of time to a mixture of pesticides (atrazine, metribuzine, endosulfan, lindane, aldicarb and dieldrin) representative in terms of composition and concentrations to what it is found in the environment of the southwest region of the province of Quebec. The pesticides were known to be present in surface water of many tributaries of the St. Lawrence River (Quebec, Canada). Our results demonstrate that the mixture of pesticides could alter the cellularity and phagocytic activity of X. laevis and the lymphocyte proliferation of R. pipiens. Taken together, these results indicate that agricultural pesticides can alter some aspects of the immune response in frogs and could contribute to their global decline by rendering them more susceptible to certain infections.
Werdin González, Jorge Omar; Jesser, Emiliano Nicolás; Yeguerman, Cristhian Alan; Ferrero, Adriana Alicia; Fernández Band, Beatriz
Mosquitoes (Diptera: Culicidae) are vectors of important parasites and pathogens causing death, poverty and social disability worldwide. The overuse of synthetic insecticides to control mosquito vectors lead to resistance, adverse environmental effects and high operational costs. Therefore, the development of eco-friendly control tools is an important public health challenge. In this study, two different essential oils (EO) (geranium, Geranium maculatum, and bergamot, Citrus bergamia) loaded polymeric nanoparticle (PN) were elaborated using polyethylene glycol (PEG) and chitosan (Qx) as the polymeric matrix/coating. In addition, the mosquito larvicidal acute and residual activity of the PN was evaluated on Culex pipiens pipiens. The physicochemical characterization of PN revealed that PEG-PN had sizes nanoparticles containing essential oil are a promising source of eco-friendly mosquito larvicidal products.
Full Text Available Andalin, a benzoylphenylurea (BPU derivative, was evaluated on Culex pipiens L. (Diptera: Culicidae. Treatment was made on newly 3rd- and 4th instar larvae for 24 h. The compound exhibited insecticidal activity and mortality occured after earlier inhibition of their development or by their inability to complete their ecdysis. Treatment resulted in a significant larvicidal effect and in a inhibition of adult emergence. Moreover, the compound disturbed growth and development since several morphological types and an increase in the duration of larval stage were observed. Histological study conducted on 4th instar larval integument, showed that Andalin caused a significant reduction in the thickness of cuticles secreted compared to controls. Thus, Andalin prevent molting in C. pipiens by interfering with cuticle deposition confirming the primary mode of action of this BPU insecticide.
Wakid, A M; Shoman, A A [Applied Biology Dept., NRC, Atomic Energy Authority. Cairo (Egypt); Amin, A H; Kansouh, A H [Plant Protection Dept., FaC. of Agriculture, Ain Shams Univ. Cairo (Egypt)
The mosquito, Culex Pipiens L. Was irradiated in the pupal stage with three gamma doses (40, 60 and 80 Gy). The effect of irradiation on the biology and ovarian development of the adult stage were assayed in comparison with a non-irradiated control group. The results showed that the gamma doses used decreased significantly adult emergence and increased malformations, while the sex ratio was not affected. fecundity of irradiated females was severely affected at 40 and 60 Gy, and 80 Gy produced in fecund females. Egg hatch ability was severely affected when males were irradiated at all doses. The gamma doses used decreased the number of ovarioles that reached the 5 th stage of christopher cycle. these ovarioles failed to produce mature eggs normally. The size of the irradiated female ovary was decreased either in length or in width at all doses used particularly at 80 Gy where the ovarian development was completely stopped on the first day of feeding. 6 figs.
Shoman, A. A.M.
The present work was carried out to investigate the effects of gamma radiation at three doses; 40,80 and 120 gray on the response of the adult mosquito culex pipiens complex when irradiated in the larval, pupal or adult stage, to the surrounding environmental factors as light, colour and host. The effects on the sexual activity of the mosquito as sex attraction , ability to inseminate and insemination frequency were also studied. Finally, the effect of 3 low dosages; 20,25 and 30 gray, applied in the pupal stage on the adult female capability to transmit filarial larvae, or in other words on the cycle development of the larvae inside the female body, was also investigated
Williams, J.J.; Wofford, H.W.
The increase in ultraviolet light intensity levels due to ozone depletion recently has been linked to the decline in amphibian population. In this experiment, eggs and larvae of Rana pipiens were subjected to differing amounts of ultraviolet radiation to determine the effects of ultraviolet light on the development of amphibian tadpoles. The total length, length of body without tail, and maximum width of each specimen was recorded for a month of the tadpoles' development, including several measurements after the ultraviolet exposures were concluded. It was found that ultraviolet exposure significantly reduced the size of the organisms in comparison with the control group in all three measured areas. Ultraviolet radiation altered the health and appearance of the exposed organisms and was lethal at large amounts. This experiment showed that ultraviolet radiation could cause many problems in developing amphibians. By slowing their development and physically weakening predation, thus contributing to a decline in overall population levels
Full Text Available Abstract Background In China, large amounts of chemical insecticides are applied in fields or indoors every year, directly or indirectly bringing selection pressure on vector mosquitoes. Culex pipiens complex has evolved to be resistant to all types of chemical insecticides, especially organophosphates, through carboxylesterases. Six resistant carboxylesterase alleles (Ester were recorded previously and sometimes co-existed in one field population, representing a complex situation for the evolution of Ester genes. Results In order to explore the evolutionary scenario, we analyzed the data from an historical record in 2003 and a recent investigation on five Culex pipiens pallens populations sampled from north China in 2010. Insecticide bioassays showed that these five populations had high resistance to pyrethroids, medium resistance to organophosphates, and low resistance to carbamates. Six types of Ester alleles, EsterB1, Ester2, Ester8, Ester9, EsterB10, and Ester11 were identified, and the overall pattern of their frequencies in geographic distribution was consistent with the report seven years prior to this study. Statistical correlation analysis indicated that Ester8 and Ester9 positively correlated with resistance to four insecticides, and EsterB10 to one insecticide. The occurrences of these three alleles were positively correlated, while the occurrence of EsterB1 was negatively correlated with Ester8, indicating an allelic competition. Conclusion Our analysis suggests that one insecticide can select multiple Ester alleles and one Ester allele can work on multiple insecticides. The evolutionary scenario of carboxylesterases under insecticide selection is possibly "one to many".
Trudeau, Vance L; Schueler, Frederick W; Navarro-Martin, Laia; Hamilton, Christine K; Bulaeva, Elizabeth; Bennett, Amanda; Fletcher, William; Taylor, Lisa
Background Amphibian declines are now recognized globally. It is also well known that many anurans do not reproduce easily in captivity, especially when held over long periods, or if they require hibernation before breeding. A simple method to induce spawning and subsequent development of large numbers of healthy tadpoles is therefore required to meet research and conservation goals. Methods The method is based on simultaneous injection of both female and male leopard frogs, Lithobates pipien...
Argueta, Tamara Belzabel Obispo; Kawada, Hitoshi; Shimabukuro, Kozue; Kubota, Shunichi; Shono, Yoshinori; Tsushima, Kazunori; Takagi, Masahiro
Comparative insecticidal efficacy of metofluthrin, a newly synthesized pyrethroid, and other pyrethroids against several colonies of Asian Culex quinquefas-ciatus (from Indonesia, Thailand, Vietnam and Malaysia) was evaluated by topical application. Metofluthrin was the most effective against the four colonies of Cx. quinquefasciatus. The LD50-based relative effective ratio of metofluthrin against d-allethrin was higher in Cx. quinquefasciatus (33.3 to 78.8) than in Cx. pipiens pallens (27.8)...
Trudeau, Vance L; Schueler, Frederick W; Navarro-Martin, Laia; Hamilton, Christine K; Bulaeva, Elizabeth; Bennett, Amanda; Fletcher, William; Taylor, Lisa
Amphibian declines are now recognized globally. It is also well known that many anurans do not reproduce easily in captivity, especially when held over long periods, or if they require hibernation before breeding. A simple method to induce spawning and subsequent development of large numbers of healthy tadpoles is therefore required to meet research and conservation goals. The method is based on simultaneous injection of both female and male leopard frogs, Lithobates pipiens (formerly called Rana pipiens) with a cocktail of a gonadotropin-releasing hormone agonist (GnRH-A) and a dopamine antagonist. We call this the AMPHIPLEX method, which is derived from the combination of the words amphibian and amplexus. Following injection, the animals are thereby induced, and perform amplexus and natural fertilization under captive conditions. We tested combinations of a GnRH agonist with 2 different dopamine antagonists in L. pipiens in the breeding season. The combination of des-Gly(10), D-Ala(6), Pro-NHEt(9)-GnRH (0.4 micrograms/g body weight; GnRH-A) with metoclopramide hydrochloride (10 micrograms/g body weight; MET) or domperidone (DOM) were equally effective, producing 89% and 88% successful spawning, respectively. This yielded more than 44,000 eggs for the 16/18 females that ovulated in the GnRH-A+MET group, and more than 39,000 eggs for the 15/17 females that ovulated in the GnRH-A+DOM group. We further tested the GnRH-A+MET in frogs collected in the wild in late autumn and hibernated for a short period under laboratory conditions, and report a low spawning success (43%). However, GnRH-A priming 24 hours prior to injections of the GnRH-A+MET cocktail in animals hibernated for 5-6 weeks produced out-of-season spawning (89%) and fertilization (85%) comparable to those we observed for in-season spawning. Assessment of age and weight at metamorphosis indicated that L. pipiens tadpoles resulting from out-of-season spawning grew normally and metamorphosed successfully. We
Paradise Christopher J
Full Text Available Abstract Background We used a simple experimental design to test for the effects of microcosm scaling on the growth and survival of the mosquito, Culex pipiens. Microcosm and mesocosm studies are commonly used in ecology, and there is often an assumption that scaling doesn't affect experimental outcomes. The assumption is implicit in the design; choice of mesocosms may be arbitrary or based on convenience or cost. We tested the hypothesis that scale would influence larvae due to depth and surface area effects. Larvae were predicted to perform poorly in microcosms that were both deep and had small openings, due to buildup of waste products, less exchange with the environment, and increased competition. To determine if the choice of scale affected responses to other factors, we independently varied leaf litter quantity, whose effects on mosquitoes are well known. Results We found adverse effects of both a lower wall surface area and lower horizontal surface area, but microcosm scale interacted with resources such that C. pipiens is affected by habitat size only when food resources are scarce. At low resource levels mosquitoes were fewer, but larger, in microcosms with smaller horizontal surface area and greater depth than in microcosms with greater horizontal surface area and shallower depth. Microcosms with more vertical surface area/volume often produced larger mosquitoes; more food may have been available since mosquitoes browse on walls and other substrates for food. Conclusions The interaction between habitat size and food abundance is consequential to aquatic animals, and choice of scale in experiments may affect results. Varying surface area and depth causes the scale effect, with small horizontal surface area and large depth decreasing matter exchange with the surrounding environment. In addition, fewer resources leads to less leaf surface area, and the effects of varying surface area will be greater under conditions of limiting resources
Ferguson, Laura V; Kirk Hillier, N; Smith, Todd G
Hepatozoon species are heteroxenous parasites that commonly infect the blood of vertebrates and various organs of arthropods. Despite their ubiquity, little is known about how these parasites affect host phenotype, including whether or not these parasites induce changes in hosts to increase transmission success. The objectives of this research were to investigate influences of the frog blood parasite Hepatozoon clamatae and the snake blood parasite Hepatozoon sipedon on host-seeking and host-choice behaviour of the mosquitoes Culex territans and Culex pipiens, respectively. During development of H. sipedon in C. pipiens, significantly fewer infected mosquitoes fed on uninfected snakes compared to uninfected mosquitoes. When H. sipedon was mature in C. pipiens, the number of infected and uninfected C. pipiens that fed on snakes was not significantly different. Higher numbers of mosquitoes fed on naturally infected snakes and frogs compared to laboratory-reared, uninfected control animals. However, experiments using only laboratory-raised frogs revealed that infection did not significantly affect host choice by C. territans. Behaviour of C. pipiens in the presence of H. sipedon may increase transmission success of the parasite and provide the first evidence of phenotypic changes in the invertebrate host of Hepatozoon parasites.
Pigeault, Romain; Villa, Manon
The transmission of Plasmodium within a vertebrate host population is strongly associated with the life history traits of its vector. Therefore the effect of malaria infection on mosquito fecundity and longevity has traditionally received a lot of attention. Several species of malaria parasites reduce mosquito fecundity, nevertheless almost all of the studies have focused only on the first gonotrophic cycle. Yet, during their lifetime, female mosquitoes go through several gonotrophic cycles, which raises the question of whether they are able to compensate the fecundity costs induced by the parasite. The impact of Plasmodium infection on female longevity is not so clear and has produced conflicting results. Here we measured the impact of Plasmodium relictum on its vector's longevity and fecundity during three consecutive gonotrophic cycles. In accordance with previous studies, we observed a negative impact of Plasmodium infection on mosquito (Culex pipiens) fecundity in the first gonotrophic cycle. Interestingly, despite having taken two subsequent uninfected blood meals, the negative impact of malaria parasite persisted. Nevertheless no impact of infection on mosquito longevity was observed. Our results are not in line with the hypothesis that the reduction of fecundity observed in infected mosquitoes is an adaptive strategy of Plasmodium to increase the longevity of its vector. We discuss the different underlying mechanisms that may explain our results.
Amin, A.H.; Kansouh, A.H.; Wakid, A.M.; Shoman, A.A.; Aly, M.A.S.
Three doses of gamma radiation (40, 60, and 80 Gy) were applied to pupae of Culex Pipiens L. An unirradiated control group was treated similarly. Newly emerged non-fed adults were assayed for carbohydrate, lipid, and protein contents in the whole body after three periods of 24,48, and 72 hours post emergence. The carbohydrate content of both sexes decreased significantly at lower doses of radiation. However, at 80 Gy, the males showed significant increase, while females showed significant decrease. Carbohydrates in both sexes were decreased with increasing the time after emergence. However, in females, carbohydrates were increased after 72 hours, at all doses tested, compared to control. The lipid content was reduced significantly with increasing gamma dose in both sexes. This content was also decreased significantly with time at all doses tested and in the controls. Irradiation decreased insignificantly protein content in the male whole body after 48 hours especially at higher doses. The reduction in female protein content at 80 Gy was very highly significant compared to control after 48 hours post emergence. Gamma irradiation with high doses reduced protein content in testes and ovaries. 9 figs
Amin, A H; Kansouh, A H [Plant Protection Dept., Fac. of Agriculture, Ain Shams Univ. Cairo (Egypt); Wakid, A M; Shoman, A A [Applied Biology Dept., NRC, Atomic Energy Authority Cairo, (Egypt); Aly, M A.S. [Radio Isotope Dept., NRC, Atomic Energy Authority Cairo (Egypt)
Three doses of gamma radiation (40, 60, and 80 Gy) were applied to pupae of Culex Pipiens L. An unirradiated control group was treated similarly. Newly emerged non-fed adults were assayed for carbohydrate, lipid, and protein contents in the whole body after three periods of 24,48, and 72 hours post emergence. The carbohydrate content of both sexes decreased significantly at lower doses of radiation. However, at 80 Gy, the males showed significant increase, while females showed significant decrease. Carbohydrates in both sexes were decreased with increasing the time after emergence. However, in females, carbohydrates were increased after 72 hours, at all doses tested, compared to control. The lipid content was reduced significantly with increasing gamma dose in both sexes. This content was also decreased significantly with time at all doses tested and in the controls. Irradiation decreased insignificantly protein content in the male whole body after 48 hours especially at higher doses. The reduction in female protein content at 80 Gy was very highly significant compared to control after 48 hours post emergence. Gamma irradiation with high doses reduced protein content in testes and ovaries. 9 figs.
Full Text Available One view of adaptation is that it proceeds by the slow and steady accumulation of beneficial mutations with small effects. It is difficult to test this model, since in most cases the genetic basis of adaptation can only be studied a posteriori with traits that have evolved for a long period of time through an unknown sequence of steps. In this paper, we show how ace-1, a gene involved in resistance to organophosphorous insecticide in the mosquito Culex pipiens, has evolved during 40 years of an insecticide control program. Initially, a major resistance allele with strong deleterious side effects spread through the population. Later, a duplication combining a susceptible and a resistance ace-1 allele began to spread but did not replace the original resistance allele, as it is sublethal when homozygous. Last, a second duplication, (also sublethal when homozygous began to spread because heterozygotes for the two duplications do not exhibit deleterious pleiotropic effects. Double overdominance now maintains these four alleles across treated and nontreated areas. Thus, ace-1 evolution does not proceed via the steady accumulation of beneficial mutations. Instead, resistance evolution has been an erratic combination of mutation, positive selection, and the rearrangement of existing variation leading to complex genetic architecture.
Full Text Available West Nile fever (WNF and Rift Valley fever (RVF are emerging diseases causing epidemics outside their natural range of distribution. West Nile virus (WNV circulates widely and harmlessly in the old world among birds as amplifying hosts, and horses and humans as accidental dead-end hosts. Rift Valley fever virus (RVFV re-emerges periodically in Africa causing massive outbreaks. In the Maghreb, eco-climatic and entomologic conditions are favourable for WNV and RVFV emergence. Both viruses are transmitted by mosquitoes belonging to the Culex pipiens complex. We evaluated the ability of different populations of Cx. pipiens from North Africa to transmit WNV and the avirulent RVFV Clone 13 strain. Mosquitoes collected in Algeria, Morocco, and Tunisia during the summer 2010 were experimentally infected with WNV and RVFV Clone 13 strain at titers of 10(7.8 and 10(8.5 plaque forming units/mL, respectively. Disseminated infection and transmission rates were estimated 14-21 days following the exposure to the infectious blood-meal. We show that 14 days after exposure to WNV, all mosquito st developed a high disseminated infection and were able to excrete infectious saliva. However, only 69.2% of mosquito strains developed a disseminated infection with RVFV Clone 13 strain, and among them, 77.8% were able to deliver virus through saliva. Thus, Cx. pipiens from the Maghreb are efficient experimental vectors to transmit WNV and to a lesser extent, RVFV Clone 13 strain. The epidemiologic importance of our findings should be considered in the light of other parameters related to mosquito ecology and biology.
Hogan, Natacha S; Lean, David R S; Trudeau, Vance L
Endocrine disrupting compounds (EDCs) are often detected in the aquatic environment and can negatively affect the health of wildlife populations. However, little is known about the sensitivity of native amphibians to EDCs. Wood frogs (Rana sylvatica) and Northern leopard frogs (Rana pipiens) were exposed to three estrogenic EDCs: estradiol (E2), ethinylestradiol (EE2), and 4-tert-octylphenol (OP). In addition, R. pipiens were exposed during two developmental stages (Gosner stages 26 and 36) to examine life-stage differences in sensitivity. Tadpoles were exposed for 2 wk to 8 nominal concentrations (0.25 microM-10 microM) of each compound. Individual mortality was recorded during the exposure period, while body weight was measured at the end of 2 wk. LC50 values were calculated, and differences in body weight between vehicle control and exposed groups were assessed. Rank order toxicity of the compounds for both R. pipiens stages and both species was OP > EE2 > E2. Gosner stage 26 tadpoles were more sensitive (LC50: E2 [5.57 microM], EE2 [3.01 microM], OP [1.36 microM]) to all three compounds when compared to stage 36 tadpoles (LC50: E2 [>10 microM], EE2 [4.17 microM], OP [2.80 microM]). Interspecies comparisons revealed R. sylvatica tadpoles (LC50: E2 [2.50 microM], EE2 [1.89 microM], OP [0.74 microM]) as being more sensitive to the three compounds than R. pipiens (LC50: E2 [4.56 microM], EE2 [2.75 microM], OP [1.42 microM]). Xenoestrogen exposure also affected tadpole body weight which may have long-term adverse effects on the rate of metamorphosis. These results provide toxicological data needed for assessing sublethal effects of estrogenic compounds on amphibian development and suggest that environmental levels of OP may pose a serious risk to the health of amphibian populations.
Huang, Y.-W.; Hoffman, D.J.; Karasov, W.H.
Northern leopard frogs Rana pipiens exposed to PCB 126 (3,3',4,4',5-pentachlorobiphenyl) were examined for hepatic oxidative stress. In a dose-response study, northern leopard frogs were injected intraperitoneally with either PCB 126 in corn oil (0.2, 0.7, 2.3, or 7.8 mg/kg body weight) or corn oil alone. In a time-course study, frogs received 7.8 mg/kg or corn oil alone, and were examined at 1, 2, 3, and 4 wk after dosing. Hepatic concentrations of reduced glutathione (GSH), thiobarbituric acid-reactive substances (TBARS), and total sulfhydryls (total SH), as well as activities of glutathione peroxidase (GSH-P), GSSG reductase (GSSG-R), glucose-6-phosphate dehydrogenase (G-6-PDH), and glutathione S-transferase (GSH-S-T) were measured. In the dose-response experiment, few effects were apparent 1 wk after dosing. In the time-course experiment, significant changes were observed in the 7.8-mg/kg group at 2 wk or more posttreatment. Hepatic concentrations of GSH and TBARS were higher than in corresponding controls at wk 3 and 4; the activities of GSSG-R and GSH-S-T were higher than in controls at wk 2 and 4; and the activity of G-6-PDH was increased at wk 2 and 4. These data collectively indicate that altered glutathione metabolism and oxidative stress occurred and were indicative of both toxicity and induction of protective mechanisms in frogs exposed to PCB. A similar delay in response was reported in fish and may relate to lower metabolic rate and physiological reactions in ectothermic vertebrates
Alout, H; Labbé, P; Berthomieu, A; Makoundou, P; Fort, P; Pasteur, N; Weill, M
We investigated the genetic determinism of high chlorpyrifos resistance (HCR), a phenotype first described in 1999 in Culex pipiens mosquitoes surviving chlorpyrifos doses ⩾1 mg l−1 and more recently found in field samples from Tunisia, Israel or Indian Ocean islands. Through chlorpyrifos selection, we selected several HCR strains that displayed over 10 000-fold resistance. All strains were homozygous for resistant alleles at two main loci: the ace-1 gene, with the resistant ace-1R allele expressing the insensitive G119S acetylcholinesterase, and a resistant allele of an unknown gene (named T) linked to the sex and ace-2 genes. We constructed a strain carrying only the T-resistant allele and studied its resistance characteristics. By crossing this strain with strains harboring different alleles at the ace-1 locus, we showed that the resistant ace-1R and the T alleles act in strong synergy, as they elicited a resistance 100 times higher than expected from a simple multiplicative effect. This effect was specific to chlorpyrifos and parathion and was not affected by synergists. We also examined how HCR was expressed in strains carrying other ace-1-resistant alleles, such as ace-1V or the duplicated ace-1D allele, currently spreading worldwide. We identified two major parameters that influenced the level of resistance: the number and the nature of the ace-1-resistant alleles and the number of T alleles. Our data fit a model that predicts that the T allele acts by decreasing chlorpyrifos concentration in the compartment targeted in insects. PMID:26463842
Schotthoefer, Anna M.; Rohr, Jason R.; Cole, Rebecca A.; Koehler, Anson V.; Johnson, Catherine M.; Johnson, Lucinda B.; Beasley, Val R.
The emergence of several diseases affecting amphibian populations worldwide has prompted investigations into determinants of the occurrence and abundance of parasites in frogs. To understand the spatial scales and identify specific environmental factors that determine risks of parasitism in frogs, helminth communities in metamorphic frogs of the northern leopard frog (Rana pipiens) were examined in relation to wetland and landscape factors at local (1 km) and regional (10 km) spatial extents in an agricultural region of Minnesota (USA) using regression analyses, ordination, and variance partitioning techniques. Greater amounts of forested and woody wetland habitats, shorter distances between woody wetlands, and smaller-sized open water patches in surrounding landscapes were the most consistently positive correlates with the abundances, richness, and diversity of helminths found in the frogs. Wetland and local landscape variables were suggested as most important for larval trematode abundances, whereas local and regional landscape variables appeared most important for adult helminths. As previously reported, the sum concentration of atrazine and its metabolite desethylatrazine, was the strongest predictor of larval trematode communities. In this report, we highlight the additional influences of landscape factors. In particular, our data suggest that anthropogenic activities that have resulted in the loss of the availability and connectivity of suitable habitats in the surrounding landscapes of wetlands are associated with declines in helminth richness and abundance, but that alteration of wetland water quality through eutrophication or pesticide contamination may facilitate the transmission of certain parasite taxa when they are present at wetlands. Although additional research is needed to quantify the negative effects of parasitism on frog populations, efforts to reduce inputs of agrochemicals into wetlands to limit larval trematode infections may be warranted
Huang, Yue-wern; Hoffman, David J; Karasov, William H
Northern leopard frogs Rana pipiens exposed to PCB 126 (3,3',4,4',5-pentachlorobiphenyl) were examined for hepatic oxidative stress. In a dose-response study, northern leopard frogs were injected intraperitoneally with either PCB 126 in corn oil (0.2, 0.7, 2.3, or 7.8 mg/kg body weight) or corn oil alone. In a time-course study, frogs received 7.8 mg/kg or corn oil alone, and were examined at 1, 2, 3, and 4 wk after dosing. Hepatic concentrations of reduced glutathione (GSH), thiobarbituric acid-reactive substances (TBARS), and total sulfhydryls (total SH), as well as activities of glutathione peroxidase (GSH-P), GSSG reductase (GSSG-R), glucose-6-phosphate dehydrogenase (G-6-PDH), and glutathione S-transferase (GSH-S-T) were measured. In the dose-response experiment, few effects were apparent 1 wk after dosing. In the time-course experiment, significant changes were observed in the 7.8-mg/kg group at 2 wk or more posttreatment. Hepatic concentrations of GSH and TBARS were higher than in corresponding controls at wk 3 and 4; the activities of GSSG-R and GSH-S-T were higher than in controls at wk 2 and 4; and the activity of G-6-PDH was increased at wk 2 and 4. These data collectively indicate that altered glutathione metabolism and oxidative stress occurred and were indicative of both toxicity and induction of protective mechanisms in frogs exposed to PCB. A similar delay in response was reported in fish and may relate to lower metabolic rate and physiological reactions in ectothermic vertebrates.
Full Text Available Background: The irritant effect of some insecticides can cause a proportion of mosquitoes to leave the sprayed rooms before acquiring a lethal dose, so the repeated contact al sub-lethal dose may lead to extent the resistance.Methods: Larvae and pupae of Culex pipiens complex were collected in mass from open canals of waste water in capital city Tehran and reared to obtain the first generation at laboratory. Sugar-fed 2–3 days female mosquitoes were used for the experiments and compared with laboratory strain. The irritability tests of insecticides impregnated papers were measured in plastic conical exposure chambers placed which implemented at controlled conditions according to the method described by WHO .Number of take-offs were counted during 15 minutes of exposure time.Results: DDT had the most irritancy effect against field population of Cx. pipiens. DDT, permethrin and deltamethrin was moderately irritable against laboratory strain, whereas, addition to three previous insecticides, malathion, cyfluthrin and propoxur should be also considered as moderately irritable insecticides for field population of. Irritability level of etofenprox, fenithrothion, bendiocarb, and lambdacyhalothrin did not differ from control group.Conclusion: The irritability response of mosquitoes may have a negative impact on control measures. Periodical execution of irritability tests with insecticides that routinely used in vector control program is highly recommended.
Alaa Sulaiman Alsobhi
Full Text Available Objective: To investigate the effectiveness of slow release formulations of Bacillus thuringiensis israelensis (AM 65-52 (B. thuringiensis israelensis and spinosyns against the West Nile vector Culex pipiens (Cx. pipiens in Saudi Arabia. Methods: We tested slow release insecticide formulations of Natular DT, Tap 60 and VectoBac granule against II instars of Cx. pipiens larvae in 50 L laboratory arenas. Results: Slow release formulations of B. thuringiensis israelensis and spinosyns gave continuous control against Cx. pipiens for several weeks. Natular DT was more effective over Tap 60 and VectoBac granule of about 1.3 and 5.8 times, respectively. Variations in the durations of effective control among the tested slow release formulations may reflect differences in their active ingredients and the mode of action. Conclusions: Our results highlighted the effectiveness of B. thuringiensis israelensis and spinosyns against an important West Nile vector, providing baseline data to develop ecofriendly mosquito control programs in Saudi Arabia.
Piwczyński, Marcin; Pape, Thomas; Deja-Sikora, Edyta
Miltogramminae is one of the phylogenetically most poorly studied taxa of the species-rich family Sarcophagidae (Diptera). Most species are kleptoparasites in nests of solitary aculeate wasps and bees, although parasitoids and saprophagous species are also known, and the ancestral miltogrammine l...
Full Text Available Abstract Background The genomes of three major mosquito vectors of human diseases, Anopheles gambiae, Aedes aegypti, and Culex pipiens quinquefasciatus, have been previously sequenced. C. p. quinquefasciatus has the largest number of predicted protein-coding genes, which partially results from the expansion of three detoxification gene families: cytochrome P450 monooxygenases (P450, glutathione S-transferases (GST, and carboxyl/cholinesterases (CCE. However, unlike An. gambiae and Ae. aegypti, which have large amounts of gene expression data, C. p. quinquefasciatus has limited transcriptomic resources. Knowledge of complete gene expression information is very important for the exploration of the functions of genes involved in specific biological processes. In the present study, the three detoxification gene families of C. p. quinquefasciatus were analyzed for phylogenetic classification and compared with those of three other dipteran insects. Gene expression during various developmental stages and the differential expression responsible for parathion resistance were profiled using the digital gene expression (DGE technique. Results A total of 302 detoxification genes were found in C. p. quinquefasciatus, including 71 CCE, 196 P450, and 35 cytosolic GST genes. Compared with three other dipteran species, gene expansion in Culex mainly occurred in the CCE and P450 families, where the genes of α-esterases, juvenile hormone esterases, and CYP325 of the CYP4 subfamily showed the most pronounced expansion on the genome. For the five DGE libraries, 3.5-3.8 million raw tags were generated and mapped to 13314 reference genes. Among 302 detoxification genes, 225 (75% were detected for expression in at least one DGE library. One fourth of the CCE and P450 genes were detected uniquely in one stage, indicating potential developmentally regulated expression. A total of 1511 genes showed different expression levels between a parathion-resistant and a
Oswaldo Paulo Forattini
Full Text Available OBJETIVO: Observar e comparar o comportamento das espécies de Aedes albopictus e de Ae. scapularis, na localidade de Pedrinhas, litoral sul do Estado de São Paulo, Brasil. MÉTODOS: As observações foram feitas de outubro de 1996 a janeiro de 2000. Foram realizadas coletas sistemáticas de formas adultas mediante a utilização de isca humana, aspirações ambientais e armadilha tipo Shannon. A domiciliação foi estimada pelo índice de Nuorteva e pela razão de sinantropia. RESULTADOS: Foram feitas 87 coletas diurnas, com a obtenção de 872 adultos fêmeas. As médias de Williams', multiplicadas por 100, foram de 118 e 21 para Ae. albopictus nos horários de 7h às 18h e de 18h às 20h, respectivamente. Quanto a Ae. scapularis, foram de 100 e 106 nos mesmos períodos. Esse último revelou pico de atividade crepuscular vespertina. Na aspiração de abrigos, obteve-se o total de 1.124 espécimens, dos quais 226 Ae. albopictus e 898 Ae. scapularis. O período de janeiro a maio correspondeu ao de maior rendimento para ambos os mosquitos. Quanto à armadilha de Shannon, as coletas realizadas na mata revelaram a ausência de Ae. albopictus. No que concerne à domiciliação, esse último mostrou os maiores valores de índices, enquanto Ae. scapularis revelou comportamento de tipo ubiquista. CONCLUSÕES: Os resultados confirmam outras observações, permitindo levantar hipóteses. Em relação a Ae. scapularis, sugere-se que possa existir fenômeno de diapausa das fêmeas no período verão-outono, a qual cessaria no inverno-primavera quando então a atividade seria retomada. Quanto a Ae. albopictus, os dados sugerem que se trata de população em processo adaptativo ao novo ambiente.OBJECTIVE: Aedes albopictus and Ae. scapularis were found living together in the Pedrinhas Village, Southeastern of São Paulo State, Brazil. This finding was a good opportunity to make observations about the mosquitoes' behavior. METHODS: From October 1996 to January 2000 observations were carried out through systematic collections with human bait, environment aspirations and Shannon trap utilization. Synanthropy was estimated by the Nuorteva index and synanthropic ratios. RESULTS: The 87 collections with human bait yield 872 females adults. Williams' means, multiplied by 100, were 118 and 21 for Ae. albopictus at the 7 AM-6PM and 6PM-8PM hours, respectively, 100 and 106 for Ae. scapularis at the same timetable but there was an evening peak. Through environmental aspirations, a total of 1,124 adults samples was collected, 226 Ae. albopictus samples and 898 Ae. scapularis samples. The period between the months of January-May was the one with higher yield for both mosquitoes. There was no Ae. albopictus in the Shannon trap operated inside the adjacent forest. Regarding the sinanthropy, that culicid showed the higher index values, while Ae. scapularis was ubiquitous. CONCLUSIONS: The data obtained allows to form the hypothesis that Ae. scapularis females may have a diapause phase in the resting places and after that period they will retake the hematophagy habit. That might explain the higher activity at the humen bait during the dry months, corresponding to the period of July-October.
Capacity of the terrestrial entomopathogenic nematode Steinernema rarum (Rhabditida: Steinernematidae to parasite Culex apicinus larvae (Diptera: Culicidae Capacidad del nemátodo terrestre entomopatógeno Steinernema rarum (Rhabditida: Steinernematidae de parasitar larvas de Culex apicinus (Diptera: Culicidae
Susana R. Cagnolo
Full Text Available Entomopathogenic nematodes can be considered effective agents for biocontrol, resulting innocuous for humans. Larvaeof Culex apicinus Philippi were exposed to infective juveniles of Steinernema rarum (OLI strain under laboratory conditions, testing six doses (1:1, 5:1, 10:1, 15:1, 100:1, 400:1. An increasing percentage of mosquito larvae mortality was recorded with an increased dose. The highest percentage of mosquito larvae mortality (75% was obtained with the dose 400:1. This is the first report of parasitism of an isolated of S. rarum from Córdoba against larvae of C. apicinus, with promising results. Therefore, further studies must be carried out to determine if these nematodes would be effective as autochthonous agents for the control of Culex Linnaeus and other mosquitoes of sanitary interest in the country.Los nemátodos entomopatógenos son considerados eficientes agentes de control de insectos plaga e inocuos para los humanos. Larvas de Culex apicinus Philippi fueron expuestas a seis dosis (1:1, 5:1, 10:1, 15:1, 100:1, 400:1 de juveniles infectivos de Steinernema rarum (aislado OLI. Se registró un incremento en la mortalidad de las larvas del mosquito con el aumento de la dosis del nematodo. El mayor porcentaje de mortalidad de larvas del mosquito (75% se obtuvo con la dosis 400:1. Este es el primer reporte de parasitismo de un aislado de S. rarum de Córdoba, en larvas de C. apicinus con resultados promisorios. Por lo tanto, se debería profundizar su estudio para determinar si pueden resultar efectivos como agentes autóctonos para el control biológico de mosquitos Culex Linnaeus, y otros de interés sanitario en el país.
Biting activity of Aedes scapularis (Rondani and Haemagogus mosquitoes in Southern Brazil (Diptera: Culicidae Atividade hematófaga de mosquitos Aedes scapularis (Rondani e Haemagogus no sul do Brasil (Diptera: Culicidae
Oswaldo Paulo Forattini
Full Text Available The biting activity of a population of Aedes scapularis (Rondani, Haemagogus capricornii Lutz and Hg. leucocelaenus (Dyar and Shannon in Southern Brazil was studied between March 1980 and April 1983. Data were obtained with 25-hour human bait catches in three areas with patchy residual forests, named "Jacaré-Pepira", "Lupo" Farm, and "Sta. Helena" Farm, in the highland region of S. Paulo State (Brazil. Data obtained on Ae. scapularis were compared with those formerly gathered in the "Ribeira'' Valley lowlands, and were similar, except in the "Lupo" Farm study area, where a precrepuscular peak was observed, not recorded at the "Jacaré-Pepira" site or in the "Ribeira" Valley. In all the areas this mosquito showed diurnal and nocturnal activity, but was most active during the evening crepuscular period. These observations support the hypothesis about the successful adaptation of Ae. scapularis to man-made environments and have epidemiological implications that arise from it. As for Haemagogus, results obtained on the "Lupo" and "Sta. Helena" regions agree with previous data obtained in several other regions and show its diurnal activity. The proximity of "Lupo" Farm, where Hg. capricornii and Hg. leucocelaenus showed considerable activity, to "Araraquara" city where Aedes aegypti was recently found, raises some epidemiological considerations about the possibility of urban yellow fever resurgence.No período de março de 1980 a abril de 1983 foi estudada a atividade hematófaga de uma população de Aedes scapularis (Rondani, Haemagogus capricornii Lutz, Hg. leucocelaenus (Dyar e Shannon, na região sul do Brasil. Os dados foram obtidos com o emprego de isca humana, mediante captura de 25 horas de duração e correspondente a três áreas, contendo manchas de floresta residual, denominadas Jacaré-Pepira, Fazenda Lupo e Fazenda Santa Helena. Os resultados relativos a Ae. scapularis foram comparados com as coletas anteriormente feitas em áreas de planície da região do Vale do Ribeira e que revelaram comportamento semelhante, exceto na Fazenda Lupo, onde foi observado um pico pré-crepuscular que não foi registrado em Jacaré-Pepira ou no Vale do Ribeira. Em todas as áreas aquele mosquito demonstrou atividade diurna e noturna. Essas observações alicerçam a hipótese sobre a capacidade de adaptação de Ae. scapularis em ambiente alterado pelo homem e as implicações epidemiológicas daí decorrentes. Quanto a Haemagogus, os dados obtidos nas Fazendas Lupo e Santa Helena concordam com os primeiros resultados obtidos em diversas outras regiões, nas quais se revela o caráter diurno de sua atividade. Nas proximidades da Fazenda Lupo, onde Hg. capricornii e Hg. leucocelaenus mostraram considerável atividade, está a cidade de Araraquara, onde o Ae. aegypti foi recentemente encontrado, e assim cabem considerações epidemiológicas, sobre a possibilidade de ocorrência de febre amarela urbana.
David Pereira Neves
Full Text Available After the Aedees albopictus has been discoved by Neves & Espinola (1987 at Minas Gerais state, we begun studying some biologic aspects, such as breeding places, host preference, times of feeding and the preferred places for blood feeding.
Impact of small variations in temperature and humidity on the reproductive activity and survival of Aedes aegypti (Diptera, Culicidae); Impacto de pequenas variacoes de temperatura e umidade na atividade reprodutiva e sobrevivencia de Aedes aegypti (Diptera, Culicidae)
Costa, Ethiene Arruda Pedrosa de Almeida; Santos, Eloina Maria de Mendonca; Correia, Juliana Cavalcanti; Albuquerque, Cleide Maria Ribeiro de, E-mail: firstname.lastname@example.org [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Centro de Ciencias Biologicas. Dept. de Zoologia
In short space of time increase in temperature and rainfall can affect vector populations and, consequently, the diseases for them transmitted. The present study analyzed the effect of small temperature and humidity variations on the fecundity, fertility and survival of Aedes aegypti. These parameters were analyzed using individual females at temperatures ranging from 23 to 27 deg C (mean 25 deg C); 28 to 32 deg C (mean 30 deg C) and 33 to 37 deg C (mean 35 deg C) associated to 60 +- 8% and 80 +- 6% relative humidity. Females responded to an increase in temperature by reducing egg production, oviposition time and changing oviposition patterns. At 25 deg C and 80% relative humidity, females survived two-fold more and produced 40% more eggs when compared to those kept at 35 deg C and 80% relative humidity. However, in 45% of females kept at 35 deg C and 60% relative humidity oviposition was inhibited and only 15% females laid more than 100 eggs, suggesting that the intensity of the temperature effect was influenced by humidity. Gradual reductions in egg fertility at 60% relative humidity were observed with the increase in temperature, although such effect was not found in the 80% relative humidity at 25 deg C and 30 deg C. These results suggest that the reduction in population densities recorded in tropical areas during seasons when temperatures reach over 35 deg C is likely to be strongly influenced by temperature and humidity, with a negative effect on several aspects of mosquito biology. (author)
Microhabitats de mosquitos (Diptera, Culicidae em internódios de taquara na Mata Atlântica, Paraná, Brasil Mosquitoes microhabitats (Diptera, Culicidae in bamboo internodes in Atlantic forest, Paraná, Brazil
Ana Leuch Lozovei
Full Text Available During two consecutive years, from January 1985 to December 1986, a comparative study of mosquitoes preferences for breeding habitat was carried out in the Atlantic Forest of the Serra do Mar, Paraná State, Brazil. To achieve it, 1875 bamboo internodes aligned vertically in live green, bamboo plants Merostachys speciosa Munro and Merostachys sp. were used, in which metabolic water was exuded from the plant itself, and presenting different size/pattern holes at their lateral walls, bored by the local sylvan fauna. Another group of 1200 individual internode traps was used as comparative element, carved out with a transversal cut by a saw, filled with local stream water and held in branches at different heights in the vegetal strata nearby. At both microhabitat types, a total of 17 culicid species was registered. Culex (Microculex neglectus Lutz, 1904, Cx. (Carrollia soperi Antunes & Lane, 1937, Sabethes (Sabethes batesi Lane & Cerqueira, 1942 and Sa. (Sabethinus melanonymphe (Dyar, 1924colonized exclusively live plant internodes, while Culex (Microculex elongatus Rozeboom & Lane, 1950, Cx. (Carrollia iridescens (Lutz, 1905, Cx. (Carrollia kompi Valencia,1973and Trichoprosopon (Trichoprosopon soaresi Dyar & Knab, 1907 bred only in internode traps. The remaining nine species colonized both habitats indistinctly. Quantitatively, was detected the abundance of 60.1% at live green internodes, against 39.9% for internode traps. Concerning the different patterns of bored live internode holes, 40.3% of the total computed specimens were collected in square or rectangular holes, 31.9% in two hole internodes, one minute circular, the other wider, and the remaining 28.8% of specimens distributed in other pattern type internodes. The mosquitoes breeding at these microhabitats fall in the culicid entomofauna specialized at locating and detecting peculiar and propitious mesogen conditions for breeding purposes.
Effects of larval crowding on development time, survival and weight at metamorphosis in Aedes aegypti (Diptera: Culicidae Efectos del hacinamiento larval en el tiempo de desarrollo, la supervivencia y el peso en la metamorfosis de Aedes aegypti (Diptera: Culicidae
Full Text Available The effects of larval crowding on survival, weight at metamorphosis and development time were assessed in the dengue mosquito, Aedes aegypti L., under a controlled environment. Larval cohorts were bred at 7 different densities (4, 8, 16, 32, 64, 128 and 256 larvae / 175 ml pot, while keeping constant water volume and food amount and quality, under controlled temperature and photoperiod. Natural detritus, mainly leaves, obtained from containers naturally colonized by A. aegypti, were used as a source of nutrients for larvae. Development time, mortality, mass at metamorphosis, and total biomass were recorded for each density. Development time ranged from 4 to 23 days in males, and from 5 to 24 in females, whereby larvae took longer to develop at 64 (females and 128 (males larvae per recipient. At high densities there was a male-biased sex proportion. At densities equal to or higher than 0.4 larvae/ml (0.32 larvae/cm² there was an increase of mortality. An inverse relationship between larval density and pupal weight was detected. Biomass per individual reached asymptotic values of about 1 mg/individual at a density of 128 individuals/pot (0.64 larvae/cm². This experiment shows that this southern strain of A. aegypti is sensitive to crowding in small containers.Los efectos del hacinamiento larval sobre el tiempo de desarrollo, la supervivencia y el peso en la metamorfosis fueron estudiados en el mosquito del dengue, Aedes aegypti L., en el laboratorio. Se criaron cohortes de larvas en 7 densidades (4, 8, 16, 32, 64, 128 y 256 larvas/ recipiente de 175 ml mientras se mantuvo constante el volumen de agua y la calidad y cantidad de alimento, bajo fotoperíodo y temperatura controlados. Se usaron detritos naturales, principalmente hojas, obtenidos de contenedores colonizados naturalmente por A. aegypti como fuente de nutrientes para las larvas. En cada densidad se registraron el tiempo de desarrollo, la mortalidad, el peso en la metamorfosis y la biomasa total. El tiempo de desarrollo varió entre 4 y 23 días en los machos, y 5 a 24 días en hembras; fue más prolongado a la densidad de 64 (en las hembras y 128 (en los machos larvas por recipiente. En densidades altas la proporción de sexos favoreció los machos. Hubo un incremento en la mortalidad en densidades iguales o mayores que 0,4 larvas/ ml (0,32 larvas/cm². Se detectó una relación inversa entre la densidad larval y el peso de las pupas. La biomasa por individuo alcanzó un valor asintótico de aproximadamente 1 mg/individuo en una densidad de 128 individuos/ recipiente (0,64 larvas/cm². Las poblaciones de A. aegypti, cercanas a su extremo sur de distribución, serían sensibles al hacinamiento en pequeños contenedores de agua.
Ciclo de vida de Aedes (Stegomyia aegypti (Diptera, Culicidae em águas com diferentes características Life cycle of Aedes (Stegomyia aegypti (Diptera, Culicidae in water with different characteristics
Eduardo B. Beserra
Full Text Available O trabalho teve por objetivo avaliar o efeito da qualidade da água no desenvolvimento de Aedes aegypti (Linnaeus, 1762. O ciclo de vida desse vetor foi estudado em águas de esgoto bruto, efluente de reator UASB, efluente de lagoa de polimento, efluente de filtro anaeróbio, água de chuva e água desclorada. Diariamente avaliaram-se o período de desenvolvimento e as viabilidades de ovo, larva, pupa, longevidade e a fecundidade dos adultos. A duração do período larval variou de 5,6 a 9,1 dias, sendo a sobrevivência baixa em águas de esgoto bruto, efluente de reator UASB, efluente de lagoa de polimento e efluente de filtro anaeróbio. Não foram observadas diferenças nas durações e viabilidades das fases de ovo e pupa, longevidade e fecundidade dos adultos. Constatou-se que, apesar da baixa viabilidade larval, é possível o desenvolvimento do A. aegypti em águas com elevados graus de poluição e que todos os tratamentos permitiram o desenvolvimento desse vetor.The present work aimed to estimate the effect of water quality in the development of Aedes aegypti (Linnaeus, 1762. The life cycle of this vector was studied in raw sewage water, effluent of UASB reactor, effluent of polishing lagoon, effluent of anaerobic filter, rainwater and de-chlorinated water. The development period, egg viability and larval and pupal survival were evaluated daily as well as the adult longevity and fecundity. The duration of larval period showed a variation of 5.6 to 9.1 days. Survival was considered low in raw sewage water, effluent of UASB reactor, effluent of polishing lagoon and effluent of anaerobic filter. No difference in terms of the duration and egg and pupal viability nor in the adult longevity and fecundity was detected. It was verified that despite a reduction in larval viability, A. aegypti could accomplish total development in waters with high pollution degree and that all the treatments were suitable to the development of this vector.
Oswaldo Paulo Forattini
Full Text Available Apresenta-se sucinta revisão do relacionamento entre as chamadas infecções emergentes e o conceito de vetores emergentes. Estes são entendidos não apenas no que concerne aos que são descritos como tais, de forma nova, mas também aqueles com acentuadas mudanças de comportamento. Os fatores específicos que propiciam esse fenômeno identificam-se à poderosa influência humana sobre o ambiente. Assim, aquele construído pelo homem e conhecido como antrópico representa a função de pressão seletiva que induz as populações vetoras a se adaptarem às novas circunstâncias. Nelas inclui-se fatores ecológicos ambientais, ou demográficos, que incrementam o contato com os novos comportamentos vetoriais. Relata-se o encontro de criadouros anômalos de mosquitos Culicidae nas Américas. A interpretação desses encontros é feita visando à vigilância epidemiológica. O significado dessa emergência ou reemergência pode se traduzir no aparecimento de problemas epidemiológicos. Sugere-se que, em sendo assim, a vigilância epidemiológica deva ser feita em grau global.A review is presented of the relationships between the so-called emerging infectious diseases and what may be defined as emerging vectors. These include not only those that have recently appeared but also those that present remarkable behavioral changes. Specific factors leading to that emergence can be associated with the powerful human influence on the environment. So the man-made, i.e. anthropic environment, exercises a selective pressure inducing vector populations to adapt to new circumstances. These may arise from ecological, environmental, or demographic factors that increase contact with the new vector. With this in mind, data on anomalous Culicidae breeding places in the Americas are reported. An interpretation of these findings is offered in the light of epidemiological surveillance. The question is whether vector emergence or re-emergence may constitute an
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.
Harburguer, Laura; Beltrán, Gaston; Goldberg, Lucila; Goldberg, Laura; Zerba, Eduardo; Licastro, Susana; Masuh, Héctor
Dengue and dengue hemorrhagic fever are mosquito-borne viral diseases that coincide with the distribution of Aedes aegypti (L.), the primary vector in the tropical and semitropical world. With no available vaccine, controlling the dengue vector is essential to avoid epidemics. This study evaluates the efficacy of a new smoke-generating formulation containing pyriproxyfen and permethrin in Puerto Libertad, Misiones, Argentina. A fumigant tablet (FT) was applied inside the houses by the community members and compared with a professional application. A treatment combining the application of fumigant tablets indoors and ultralow volume fumigation outdoors was also assessed. The community perceptions and practices about dengue disease and the acceptance of this new nonprofessional FT were evaluated through surveys. Results show >90% adult emergence inhibition and 100% adult mortality with these treatments. More than 80% of the residents applied the FT and preferred participating in a vector control program by using a nonprofessional mosquito control tool, instead of attending meetings and workshops promoting cultural changes.
Tarek M.Y. El-Sheikh
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.
Francisco Augusto da Silva Ferreira
Full Text Available ABSTRACTWe analyzed the effects of Bacillus sphaericus on Anopheles larvae and on the associated insect fauna in fish farming ponds. Five breeding sites in the peri-urban area of the city of Manaus, AM, Brazil, were studied. Seven samples were collected from each breeding site and B. sphaericus was applied and reapplied after 15 days. The samples were made at 24 h before application, 24 h post-application and 5 and 15 days post-application. We determined abundance, larval reduction and larval density for Anopheles, and abundance, richness, Shannon diversity index and classified according to the functional trophic groups for associated insect fauna. A total of 904 Anopheles larvae were collected and distributed into five species. Density data and larval reduction demonstrated the rapid effect of the biolarvicide 24 h after application. A total of 4874 associated aquatic insects belonging to six orders and 23 families were collected. Regression analysis of diversity and richness indicated that the application of the biolarvicide had no influence on these indices and thus no effect on the associated insect fauna for a period of 30 days. B. sphaericus was found to be highly effective against the larvae of Anopheles, eliminating the larvae in the first days after application, with no effect on the associated insect fauna present in the fish ponds analyzed.
Luiz Herman Soares GIL
Full Text Available We conducted a survey of the malaria vectors in an area where a power line had been constructed, between the municipalities of Porto Velho and Rio Branco, in the states of Rondônia and Acre, respectively. The present paper relates to the results of the survey of Anopheles fauna conducted in the state of Rondônia. Mosquito field collections were performed in six villages along the federal highway BR 364 in the municipality of Porto Velho, namely Porto Velho, Jaci Paraná, Mutum Paraná, Vila Abunã, Vista Alegre do Abunã, and Extrema. Mosquito captures were performed at three distinct sites in each locality during the months of February, July, and October 2011 using a protected human-landing catch method; outdoor and indoor captures were conducted simultaneously at each site for six hours. In the six sampled areas, we captured 2,185 mosquitoes belonging to seven Anopheles species. Of these specimens, 95.1% consisted of Anopheles darlingi, 1.8% An. triannulatus l.s., 1.7% An. deaneorum, 0.8% An. konderi l.s., 0.4 An. braziliensis, 0.1% An. albitarsis l.s., and 0.1% An. benarrochi. An. darlingi was the only species found in all localities; the remaining species occurred in sites with specific characteristics.
Airleth Sofía Díaz
Conclusion: Anopheles albimanus was the only collected species found in water supply deposits in the villages Marbacella and El Horno. Given that the species is the main vector for malaria in the area, we suggest the implementation of a community-based entomological surveillance system which should respect Wayúu cosmology and routine activities such as fishing.
Full Text Available Abstract Background Aedes (Stegomyia albopictus is currently one of the most notorious globally invasive mosquito species. Its medical importance is well documented, and its fast expansion throughout most continents is being monitored with concern. It is generally assumed that its expansion through the Western Pacific island countries has not progressed since its establishment in Fiji in 1989. However, the current status of Ae. albopictus in the Pacific region is largely unknown. Findings According to data from the literature and our own observations, Ae. albopictus is currently present in the following countries of the southern Pacific region: Papua New Guinea, Solomon Islands, Fiji, and the Kingdom of Tonga, where it was first detected in July 2011. It is absent from New Caledonia and French Polynesia where routine entomological surveillance is carried out, and was not detected during entomological work in 2007, either on the Cook Islands or on the Wallis and Futuna Islands. The species was not reported from American Samoa in 2004, but it is mentioned as probably present in Vanuatu. This is the first report of Ae. albopictus in Tonga. Conclusions The introduction and establishment of Ae. albopictus in Tonga was expected due to the geographical proximity of this country to Fiji where the species is strongly established. The pathway of introduction is unknown. The expansion of Ae. albopictus in the Pacific region poses an increasing threat to public health given the role this mosquito plays as primary vector of emerging infectious diseases such as Chikungunya fever.
Nur Endah Wahyuningsih
Full Text Available The control of dengue hemorrhagic fever (DHF it is important to control the vector, i.e. Aedes aegypti (Linnaeus and Ae. albopictus (Skuse. Usually, controls of these vectors are done using chemical insecticides. Research on mosquito resistance has been done, but the impact of mosquitoes that survive after synthetic (chemical insecticides application has not been studied. The aim of this research was to analyze the differences of fecundity, fertility and vitality rate of mosquitoes that were exposed to natural insecticides i.e with burned breadnut flowers and mosquito coils containing transflutrin and d-aletrin. Mosquito samples were taken from field eggs which were exposed with synthetic and natural insecticides. Mosquitoes that remainder alive after 24 hours exposure were mated and each group were put in 2 cages, each repetition were repeated 3 times. The mosquito eggs were observed until adult mosquitoes die. Then, the fecundity, fertility and vitality rate were compared. Based on our analysis, there were no differences on fecundity rate, between control and mosquitoes that were exposed to natural insecticides, but there were significant differences between the control and the synthetic insecticides. Natural insecticides do not increase the rate of fecundity but synthetic insecticides may increase the rate of fecundity and number of mosquitoes and causes the mosquito lifespan longer than the control and natural insecticide treatment.
Gouagna Louis C
Full Text Available Abstract Background The origin of highly competent malaria vectors has been linked to productive larval habitats in the field, but there isn't solid quantitative or qualitative data to support it. To test this, the effect of larval habitat soil substrates on larval development time, pupation rates and vector competence of Anopheles gambiae to Plasmodium falciparum were examined. Methods Soils were collected from active larval habitats with sandy and clay substrates from field sites and their total organic matter estimated. An. gambiae larvae were reared on these soil substrates and the larval development time and pupation rates monitored. The emerging adult mosquitoes were then artificially fed blood with infectious P. falciparum gametocytes from human volunteers and their midguts examined for oocyst infection after seven days. The wing sizes of the mosquitoes were also measured. The effect of autoclaving the soil substrates was also evaluated. Results The total organic matter was significantly different between clay and sandy soils after autoclaving (P = 0.022. A generalized liner model (GLM analysis identified habitat type (clay soil, sandy soil, or lake water and autoclaving (that reduces presence of microbes as significant factors affecting larval development time and oocyst infection intensities in adults. Autoclaving the soils resulted in the production of significantly smaller sized mosquitoes (P = 0.008. Autoclaving clay soils resulted in a significant reduction in Plasmodium falciparum oocyst intensities (P = 0.041 in clay soils (unautoclaved clay soils (4.28 ± 0.18 oocysts/midgut; autoclaved clay soils = 1.17 ± 0.55 oocysts/midgut although no difference (P = 0.480 in infection rates was observed between clay soils (10.4%, sandy soils (5.3% or lake water (7.9%. Conclusion This study suggests an important nutritional role for organic matter and microbial fauna on mosquito fitness and vector competence. It shows that the quality of natural aquatic habitats of mosquito larvae may influence malaria parasite transmission potential by An. gambiae. This information can be important in targeting larval habitats for malaria control.
Chemicals can protect humans from the bites 30 of hemophagous arthropods through three different primary actions; irritancy (excitation), repellency, or toxicity; actions that can be evaluated using a laboratory-based assay system. In this study, the deterrent and toxic actions of three synthetic py...
Jesús Eduardo Escovar
Full Text Available Since 1984, Anopheles (Kerteszia lepidotus has been considered a mosquito species that is involved in the transmission of malaria in Colombia, after having been incriminated as such with epidemiological evidence from a malaria outbreak in Cunday-Villarrica, Tolima. Subsequent morphological analyses of females captured in the same place and at the time of the outbreak showed that the species responsible for the transmission was not An. lepidotus, but rather Anopheles pholidotus. However, the associated morphological stages and DNA sequences of An. pholidotus from the foci of Cunday-Villarrica had not been analysed. Using samples that were caught recently from the outbreak region, the purpose of this study was to provide updated and additional information by analysing the morphology of female mosquitoes, the genitalia of male mosquitoes and fourth instar larvae of An. pholidotus, which was confirmed with DNA sequences of cytochrome oxidase I and rDNA internal transcribed spacer. A total of 1,596 adult females were collected in addition to 37 larval collections in bromeliads. Furthermore, 141 adult females, which were captured from the same area in the years 1981-1982, were analysed morphologically. Ninety-five DNA sequences were analysed for this study. Morphological and molecular analyses showed that the species present in this region corresponds to An. pholidotus. Given the absence of An. lepidotus, even in recent years, we consider that the species of mosquitoes that was previously incriminated as the malaria vector during the outbreak was indeed An. pholidotus, thus ending the controversy.
Lauren F. Collins
Full Text Available The Asian tiger mosquito, Aedes albopictus, is a competent vector for arboviruses and recently was implicated as the vector of the first autochthonous cases of dengue and chikungunya in southern Europe. The objective of this study was to analyze the flight performance of female Ae. albopictus of different ages that were starved, sugar-fed, or sugar-fed and blood-fed, using flight mills. After three days of starvation post emergence, females flew an average distance of 0.7 ± 0.5 km in 1.9 ± 1.5 h during a 16 h trial period, whereas sugar- or sugar- and blood-fed females of this age covered a significantly higher distance of around 3 km with a mean total flight time of around 6 h. The age of females (up to four weeks had no effect on performance. The average of maximal continuous flight segments of sugar-fed (2.14 ± 0.69 h and blood-fed (3.17 ± 0.82 h females was distinctly higher than of starved females (0.38 ± 0.15 h of which most flyers (83% performed maximal flight segments that lasted no longer than 0.5 h. Overall, the results for the laboratory monitored flight performance of Ae. albopictus confirm their ability to disperse a few kilometres between breeding site and host.
rhesus, le premier indemne, le second infeste par Plasmodium cynomolgi. Vingt moustiques gorges de sang constituaient le groupe temoin non infest& et...60 autres moustiques infest& ont ete divises en trois groupes de 20 moustiques (groupes infest& 1, 2 et 3). On a evaI& le nombre moyen d’oocystes...port& par les moustiques en dissequant ceux du groupe 1 au septieme jour de I’etude; on a recherche la presence de sporozo’ites dans les glandes
V. C. Soares-Pinheiro
Full Text Available Abstract The viability of Aedes aegypti eggs was assessed in the Amazon region. The eggs were maintained under different conditions: indoors (insectarium and outdoors (natural environment, as well as in different storage types (plastic cup, paper envelope, plastic bag for different days. Egg viability was measured as the mean of hatchings observed from egg-bearing sheets of filter paper immersed in water, using three sheets randomly selected from each storage type and at both sites. There were significant differences in the viability of Ae. aegypti eggs with respect to the location (F=30.40; DF=1; P<0.0001, storage type (F=17.66; DF=2; P<0.0001, and time of storage (F=49.56; DF=9; P<0.0001. The interaction between storage site versus storage type was also significant (F=15.96; DF=2; P<0.0001. A higher hatching mean was observed for the eggs kept in the insectarium than for those outdoors (32.38 versus 7.46. Hatching rates of egg batches stored for 12 to 61 days ranged between 84 and 90%. A reduction was observed between 89 and 118 days, with values of 63 and 48%, respectively. With respect to type of storage, mean egg hatching was higher for the eggs in plastic cups (44.46. It was concluded that the viability of the eggs of Ae. aegypti in the Amazon region remains high up to 4 months, after which it declines drastically, although in this study hatching occurred for up to 8 months in very low percentages.
Full Text Available INTRODUCTION: Dengue is a serious public health problem worldwide, with cases reported annually in tropical and subtropical regions. Aedes aegypti (Linnaeus, 1762, the main vector of dengue, is a domiciliary species with high dispersal and survival capacities and can use various artificial containers as breeding sites. We assessed potential container breeding sites of A. aegypti in the municipality of Caxias, Maranhão, Brazil. METHODS: In the initial phase, we analyzed 900 properties in 3 neighborhoods during the dry and rainy seasons (August-October 2005 and February-April 2006, respectively. During the second sampling period, September 2006-August 2007, we used 5 assessment cycles for 300 properties in a single neighborhood. RESULTS: During the dry and rainy seasons, water-storage containers comprised 55.7% (n = 1,970 and 48.5% (n = 1,836 of the total containers inspected, and showed the highest productivity of immature A. aegypti; we found 23.7 and 106.1 individuals/container, respectively, in peridomicile sites. In intradomicile sites, water-storage containers were also the most important breeding sites with 86.4% (n = 973 and 85.6% (n = 900 of all containers and a mean of 7.9 and 108.3 individuals/container in the dry and rainy seaso-October 2006 (1,342. The highest number of positives (70 was recorded in May, mostly (94% in storage containers. CONCLUSIONS: Storage containers are the principal and most productive A. aegypti breeding sites and are a major contributing factor to the maintenance of this vector in Caxias.
Soares-da-Silva, Joelma; Ibiapina, Sebastiana Silva; Bezerra, Juliana Maria Trindade; Tadei, Wanderli Pedro; Pinheiro, Valéria Cristina Soares
Dengue is a serious public health problem worldwide, with cases reported annually in tropical and subtropical regions. Aedes aegypti (Linnaeus, 1762), the main vector of dengue, is a domiciliary species with high dispersal and survival capacities and can use various artificial containers as breeding sites. We assessed potential container breeding sites of A. aegypti in the municipality of Caxias, Maranhão, Brazil. In the initial phase, we analyzed 900 properties in 3 neighborhoods during the dry and rainy seasons (August-October 2005 and February-April 2006, respectively). During the second sampling period, September 2006-August 2007, we used 5 assessment cycles for 300 properties in a single neighborhood. During the dry and rainy seasons, water-storage containers comprised 55.7% (n = 1,970) and 48.5% (n = 1,836) of the total containers inspected, and showed the highest productivity of immature A. aegypti; we found 23.7 and 106.1 individuals/container, respectively, in peridomicile sites. In intradomicile sites, water-storage containers were also the most important breeding sites with 86.4% (n = 973) and 85.6% (n = 900) of all containers and a mean of 7.9 and 108.3 individuals/container in the dry and rainy seaso-October 2006 (1,342). The highest number of positives (70) was recorded in May, mostly (94%) in storage containers. Storage containers are the principal and most productive A. aegypti breeding sites and are a major contributing factor to the maintenance of this vector in Caxias.
Full Text Available The mosquito Aedes aegypti is the vector of the dengue virus, an endemic arbovirus from tropical and subtropical regions of the world. The increasing resistance of mosquitoes to commercial insecticides impairs regular control programs; therefore, chemical prospecting originating from the Amazonian flora is promising for potential new insecticides. Several Piper species are, notably, rich in phenylpropanoids and terpenoids, substances with proven insecticidal activity. The composition and the larvicidal activity of three Piper species against A. aegypti were evaluated. Essential oils were extracted by hydrodistillation in a modified Clevenger apparatus and analyzed by GC/MS. The major components found in Piper arboreum were germacrene D (31.83% and bicyclogermacrene (21.40%; in Piper marginatum: (E-methyl isoeugenol (27.08%, (E-anethole (23.98% and (Z-methyl isoeugenol (12.01%; and in Piper aduncum: (E-isocroweacin (29.52% and apiole (28.62% and elemicin (7.82%. Essential oils from the Piperaceae species studied resulted in Lethal Concentrations (LC50 of 34-55 ppm, while LC90 was higher than 100 ppm, except for P. marginatum (85 ppm.
WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Walter Reed Army Institute of Research,Division of Entomology,Silver Spring,MD...20910-7500 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S) 11...four, palpomere 5 absent or minute; (2) three, palpomere 4 absent or vestigial ; (3) two, palpomere 3 absent or vestigial . *13(158). Maxillary
Full Text Available The Asian tiger mosquito Aedes albopictus is the most dominant species of subgenus Stegomyia and is medically important from the standpoint of transmitting wide range of human pathogens of deadly diseases like dengue, yellow fever and chikungunya. During present investigations, it has been observed that IX tergum in the male genitalia of Aedes albopictus varies greatly. It shows variations with respect to the presence or absence of lateral projections on the IX tergum, as well as in the shape and size of median and lateral projections. The shape of IX tergum in the male genitalia of Aedes species is of great taxonomic importance as it is a diagnostic character of the species. These variations have been observed both in natural populations collected from various breeding sites as well as in the adults reared in laboratory. The observed differences have not been noticed by any of the previous workers.
Full Text Available Cemeteries with many water-filled containers, flowers, sources of human blood, and shade are favorable urban habitats for the proliferation of Aedes aegypti, a vector of yellow fever and dengue. A total of 22,956 containers was examined in the five cemeteries of the city of Buenos Aires, Argentina. The vector was found in four cemeteries that showed an average infestation level of 5.5% (617 positive out of 11,196 water-filled containers. The four cemeteries positive for Ae. aegypti showed significantly different (p<0.01 infestation levels. Vegetation cover and percentage of infestation were significantly correlated (p<0.01, but neither cemetery area nor number of available containers were significantly related to the proportion of positive vases. Our results suggest that the cemeteries of Buenos Aires represent a gradient of habitat favorableness for this vector species, some of which may act as foci for its proliferation and dispersal.
Mdoe, France P; Nkwengulila, Gamba; Chobu, Mariam; Lyaruu, Lucile; Gyunda, Israel L; Mbepera, Saada; Xue, Rui-De; Kweka, Eliningaya J
Mosquito larval control using chemicals and biological agents is of paramount importance in vector population and disease incidence reduction. A commercial synthetic disinfectant soap was evaluated against larvae of Anopheles gambiae s.s. in both laboratory and semi field conditions. Five concentrations of commercial synthetic disinfectant soap (0.0001, 0.001, 0.01, 0.1 and 1%) were prepared and evaluated against third instar larvae in laboratory and semi field environments. Mortality was scored at 12, 24, 48, and 72 hrs. Each dosage had 6 replicates, having twenty 3rd instar larvae of An.gambiae s.s. In the laboratory phase, all dosages had significantly higher larval mortalities than in controls, while in semi field conditions, the dosages of 0.0001, 0.001 and 0.01% had lower mortalities than laboratory trials. In the comparison between semi field and laboratory trials, only 0.1 and 1% dosage had significant difference with more mortality in semifield conditions. Proportions of larvae that died during mortality monitoring intervals in laboratory and semi field had significant differences only at 12 hrs and 72 hrs. The findings of this study have demonstrated that the mortality of larvae caused by commercial synthetic disinfectant soap is worth further studies in open water bodies. More studies are necessary to find out the effect of sunlight on the chemistry of the synthetic disinfectant and other variables in small scale full field trials.
Allan Kardec Ribeiro Galardo
Full Text Available Abstract: INTRODUCTION: This study aimed to evaluate the susceptibility of Anopheles darlingi Root (1926 and Anopheles marajoara Galvão & Damasceno (1942 to pyrethroids used by the National Malaria Control Program in Brazil. METHODS: Mosquitoes from Amapá, Brazilian Amazon, were assessed for resistance to cypermethrin, deltamethrin, and alpha-cypermethrin. Insecticide-impregnated bottles were used as suggested by the CDC/Atlanta. RESULTS: Diagnostic dose for Anopheles darlingi was 12.5µg/bottle during 30 min of exposure. Concentrations for Anopheles marajoara were 20µg/bottle of cypermethrin and deltamethrin and 12.5µg/bottle of alpha-cypermethrin. CONCLUSIONS : No resistance was recorded for Anopheles darlingi , but Anopheles marajoara requires attention.
Full Text Available In recent years, the development of new tools to gather field information about vector ecological parameters has increased. This report evaluated the BG-Sentinel Trap (BGS-Trap, a promising new attempt to improve collection of the dengue vector, Aedes aegypti. The efficacy of the BGS-Trap was compared with the CDC backpack aspirator, one of the commonest used methods for capturing adult mosquitoes. BGS-Traps captured significantly more Ae. aegypti males (chi2 = 21.774, df = 1, P < 0.05 and females (chi2 = 56.007, df = 1, P < 0.05 than CDC aspirator during all days of field collection. However, CDC aspirator was significantly more efficient to capture Culex quinquefasciatus males (chi2 = 5.681, df = 1, P < 0.05 and females (chi2 = 6.553, df = 1, P < 0.05. BGS-Traps captured host-seeking females (varying between 68.75 to 89.8% in detriment of females in other behavioral and physiological stages. BGS-Traps proved to be efficient and can be used for monitoring adult mosquito populations.
Maximum parsimony; Sibling species; Species complex; Myxomatosis ; DNA barcoding; Australia; Papua New Guinea; ITS2; COI; COII; EF-11. Introduction... myxomatosis to con- trol rabbits (Fenner and RatcliVe, 1965). Chris Green used data from cross-matings and the band- ing pattern of polytene chromosomes to... myxomatosis based on distribution but more sam- pling is required to conWrm this. Many of the sampling locations in this study and the allozyme study of
important vector of myxomatosis in many areas of Australia (Fenner & Ratcliffe. 1965; Parer & Korn, 1989), and a number of other arboviruses have been...Fenner & Ratcliffe, 1965). Although an epidemiological assessment of the role in myxomatosis transmission of the different sibling spe- cies will have to...tlats at Merbein, VIC predominantly fed on rab- bits despite the rabbit population having been deci- mated by myxomatosis . As Merbein is near Mildura, VIC
Margareth Regina Dibo
Full Text Available Introduction Here, we evaluated sweeping methods used to estimate the number of immature Aedes aegypti in large containers. Methods III/IV instars and pupae at a 9:1 ratio were placed in three types of containers with, each one with three different water levels. Two sweeping methods were tested: water-surface sweeping and five-sweep netting. The data were analyzed using linear regression. Results The five-sweep netting technique was more suitable for drums and water-tanks, while the water-surface sweeping method provided the best results for swimming pools. Conclusions Both sweeping methods are useful tools in epidemiological surveillance programs for the control of Aedes aegypti.
Knols, B.G.J.; Njiru, B.N.; Mathenge, E.M.; Mukabana, W.R.; Beier, J.C.; Killeen, G.F.
The development and implementation of innovative vector control strategies for malaria control in Africa requires in-depth ecological studies in contained semi-field environments. This particularly applies to the development and release of genetically-engineered vectors that are refractory to
Dorothee E Zielke
Full Text Available The mosquito Aedes japonicus japonicus, originally restricted to temperate East Asia, is now widespread in North America and more recently has become established in Europe. To ascertain the putative number of separate introductions to Europe and examine patterns of expansion we analyzed the genetic makeup of Ae. j. japonicus populations from five cemeteries in North Rhine-Westphalia and Rhineland-Palatinate, two western German federal states, as well as of specimens from populations in Belgium, Switzerland, and Austria/Slovenia. To do so, we genotyped individual specimens at seven pre-existing polymorphic microsatellite loci and sequenced part of the nad4 mitochondrial locus. We found evidence of two different genotypic signatures associated with different nad4 mitochondrial haplotypes, indicating at least two genetically differentiated populations of Ae. j. japonicus in Europe (i.e. two distinct genotypes. Belgian, Swiss, and Austrian/Slovenian populations all share the same genotypic signature although they have become differentiated since isolation. Contrary to expectations, the German Ae. j. japonicus are not closely related to those in Belgium which are geographically nearest but are also highly inbred. German populations have a unique genotype but also evidence of mixing between the two genotypes. Also unexpectedly, the populations closest to the center of the German infestation had the highest levels of admixture indicating that separate introductions did not expand and merge but instead their expansion was driven by punctuated human-mediated transport. Critically, the resulting admixed populations have higher genetic diversity and appear invasive as indicated by their increased abundance and recent spread across western Germany.
Giatropoulos, Athanassios; Pitarokili, Danae; Papaioannou, Fotini; Papachristos, Dimitrios P; Koliopoulos, George; Emmanouel, Nickolaos; Tzakou, Olga; Michaelakis, Antonios
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.
Ralph E. Harbach
Full Text Available We report the discovery of Aedes nigrinus (Eckstein, 1918 in the New Forest of southern England, bringing to 36 the number of mosquito species recorded in Britain. Because it seems that this species has been misidentified previously in Britain as the morphologically similar Aedes sticticus (Meigen, 1838, the two species are contrasted and distinguished based on distinctive differences exhibited in the adult and larval stages. The pupa of Ae. nigrinus is unknown, but the pupa of Ae. sticticus is distinguished from the pupae of other species of Aedes by modification of the most recent key to British mosquitoes. The history of the mosquito fauna recorded in the UK is summarized and bionomical information is provided for the two species.
aegypti females lay their eggs in many sites (Harrington and Ed- man, 2001; Reiter, 2007). This behavior im- proves likelihood of survival. Blood-fed Ae...coiled into skeins) or parous ( ovaries stretched and uncoiled) (Service, 1993). Blood-fed, gravid females were not dissected but classified as...deposition. Ishaaya and Horowitz (1992) found newly deposited eggs (0-1 day old) from female sweet- A PyriProxyfen TreATed device for Ae. Aegypti
Full Text Available Aedes aegypti is the main insect vector of Dengue fever and dengue hemorrhagic fever/dengue shock syndrome and represents the only vulnerable element in the control of this disease. Therefore, the identification and quantification of this mosquito is an important task; however, the majority of taxonomic keys are based on the 4th larval instar. For that reason, this study describes the four larval instars of A. aegypti using scanning electron microscopy. Morphological changes during larval development were observed at the pecten, comb scales and the ventral brush of the abdominal segment X; however, the 3rd and 4th instars showed similar structures with only a slight variation. The structures described in this study will be helpful in the identification of the four instars of A. aegypti, a fundamental task for comprehending the natural history of dengue mainly in new territories affected. Rev. Biol. Trop. 54 (3: 847-852. Epub 2006 Sept. 29.Aedes aegypti es el principal insecto vector de la fiebre del dengue y del dengue hemorrágico/síndrome del choque por dengue y es el único elemento atacable para el control de esta virosis. La identificación y cuantificación de éste es una tarea importante; no obstante, la mayoría de las llaves taxonómicas se basan en el cuarto estadio larval. Por esta razón, en este trabajo se describen los cuatro estadios larvales de A. aegypti los cuales fueron examinados mediante microscopia electrónica de rastreo. Los cambios morfológicos ocurridos durante el desarrollo larval fueron observados en el pecten, las escamas del peine, el cepillo ventral del décimo segmento. El 3ero y 4to estadios larvales mostraron estructuras similares con sólo ligeras variaciones. Las estructuras descritas en este artículo permiten identificar cualquiera de los cuatro estadios larvales de A. aegypti, lo cual representa una tarea importante en la comprensión de la historia natural del dengue en los nuevos territorios afectados.
Lather, Manila; Sharma, Divya; Dang, Amita S; Adak, Tridibes; Singh, Om P
Anopheles fluviatilis James is an important malaria vector in India, Pakistan, Nepal, and Iran. It has now been recognized as a complex of at least four sibling species-S, T, U, and V, among which species T is the most widely distributed species throughout India. The taxonomic status of these species is confusing owing to controversies prevailing in the literature. In addition, chromosomal inversion genotypes, which were considered species-diagnostic for An. fluviatilis species T, are unreliable due to the existence of polymorphism in some populations. To study the genetic diversity at population level, we isolated and characterized 20 microsatellite markers from microsatellite-enriched genomic DNA library of An. fluviatilis T, of which 18 were polymorphic while two were monomorphic. The number of alleles per locus among polymorphic markers ranged from 4 to 19, and values for observed and expected heterozygosities varied from 0.352 to 0.857 and from 0.575 to 0.933, respectively. Thirteen markers had cross-cryptic species transferability to species S and U of the Fluviatilis Complex. This study provides a promising genetic tool for the population genetic analyses of An. fluviatilis. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
Rutledge, C Roxanne; Day, Jonathan F; Lord, Cynthia C; Stark, Lillian M; Tabachnick, Walter J
We describe the first documented field transmission of West Nile (WN) virus by a North American mosquito. WN was first detected in northern Florida in 2001. An intensive mosquito trapping and surveillance program was conducted in this region for four nights to assess mosquito transmission of WN. Four mosquito traps, each with a single sentinel chicken, were placed at five different locations on each of four nights. A total of 11,948 mosquitoes was collected, and 14 mosquito pools were found to contain WN, giving a minimum infection rate between 1.08 and 7.54 per 1,000. Only one of the 80 sentinel chickens seroconverted to WN, demonstrating a single mosquito transmission event during the study and a mosquito transmission rate of between 0.8 and 1 per 1,000. Culex nigripalpus Theobald was responsible for WN transmission to the sentinel chicken, although both Cx. nigripalpus and Culex quinquefasciatus Say were found infected with WN. Mosquito transmission rates are reported in this study for the first time for a WN outbreak. This information is essential to determine risk of human and animal infection.
Richards, Stephanie L; Anderson, Sheri L; Lord, Cynthia C; Tabachnick, Walter J
Female Culex nigripalpus were fed blood containing a low dose (6.3±0.01 logs plaque-forming units (PFU)/mL) or high dose (7.3±0.1 logs PFU/mL) of West Nile virus (WNV) and maintained at 28°C for incubation periods (IPs) of 6 or 12 days. Vector competence was measured using rates of infection (% with WNV-positive bodies), dissemination (% infected with WNV-positive legs), and transmission (% infected with WNV-positive saliva). Infection rates were not influenced by dose or IP. Dissemination rates were significantly higher at the high dose, and this was dependent on IP. Despite 100% infection and 90% dissemination in the most permissive treatment of high dose and 12 days, only 11% transmission was observed. Virus titers in body and leg tissues were significantly lower at the low dose and the titers were not influenced by IP. We show that not all mosquitoes with infections and/or disseminated infections transmit WNV under the conditions of this test. Therefore, characterizing the transmission ability of a vector population using infection or dissemination as indicators of transmission may provide inaccurate information. The complex relationships between infection, dissemination, and transmission must be evaluated under a variety of biological and environmental conditions to begin to assess the epidemiological risk of natural mosquito populations.
Alarcón-Elbal, Pedro María; Estrella, Sarah Delacour; Arrondo, Ignacio Ruiz; Collantes, Francisco; Iniesta, Juan Antonio Delgado; Morales-Bueno, José; Sánchez-López, Pedro Francisco; Amela, Carmen; Sierra-Moros, María José; Molina, Ricardo; Lucientes, Javier
In 2004, Aedes (Stegomyia) albopictus (Skuse, 1894) was observed for the first time in Catalonia, northeastern Spain. A decade later, it has spread throughout the eastern Mediterranean region of the country and the Balearic Islands. Framed within a national surveillance project, we present the results of monitoring in 2013 in the autonomous communities of the mainland Levante. The current study reveals a remarkable increase in the spread of the invasive mosquito in relation to results from 2012; the species was present and well-established in 48 municipalities, most of which were along the Mediterranean coastline from the Valencian Community to the Region of Murcia. PMID:25317706
Neira Oviedo MV
Full Text Available Marco V Neira Oviedo1,2, William S Romoser1, Calvin BL James1, Farida Mahmood3, William K Reisen31Tropical Disease Institute, Department of Biomedical Sciences, College of Osteopathic Medicine, Ohio University, Athens, OH, USA; 2Oxitec Inc, Oxford, England; 3Center for Vectorborne Diseases, School of Veterinary Medicine, University of California, Davis, CA, USABackground: Vector competence describes the efficiency with which vector arthropods become infected with and transmit pathogens and depends on interactions between pathogen and arthropod genetics as well as environmental factors. For arbovirus transmission, the female mosquito ingests viremic blood, the virus infects and replicates in midgut cells, escapes from the midgut, and disseminates to other tissues, including the salivary glands. Virus-laden saliva is then injected into a new host. For transmission to occur, the virus must overcome several "barriers", including barriers to midgut infection and/or escape and salivary infection and/or escape. By examining the spatial/temporal infection dynamics of Culex tarsalis strains infected with western equine encephalomyelitis virus (WEEV, we identified tissue tropisms and potential tissue barriers, and evaluated the effects of viral dose and time postingestion.Methods: Using immuno-stained paraffin sections, WEEV antigens were tracked in four Cx. tarsalis strains: two recently colonized California field strains – Coachella Valley, Riverside County (COAV and Kern National Wildlife Refuge (KNWR; and two laboratory strains selected for WEEV susceptibility (high viremia producer, HVP, and WEEV resistance (WR.Results and conclusions: Tissues susceptible to WEEV infection included midgut epithelium, neural ganglia, trachea, chorionated eggs, and salivary glands. Neuroendocrine cells in the retrocerebral complex were occasionally infected, indicating the potential for behavioral effects. The HVP and COAV strains vigorously supported viral growth, whereas the WR and KNWR strains were less competent. Consistent with earlier studies, WEEV resistance appeared to be related to a dose-dependent midgut infection barrier, and a midgut escape barrier. The midgut escape barrier was not dependent upon the ingested viral dose. Consistent with midgut infection modulation, disseminated infections were less common in the WR and KNWR strains than in the HVP and COAV strains. Once the virus disseminated from the midgut, all strains were able to develop salivary gland infections. The possible roles of observed pathology will be discussed in a subsequent paper.Keywords: western equine encephalomyelitis virus, Culex tarsalis, vector competence, viral tropism, mosquito/virus interaction
Oviedo, Marco V Neira; Romoser, William S; James, Calvin Bl; Mahmood, Farida; Reisen, William K
BACKGROUND: Vector competence describes the efficiency with which vector arthropods become infected with and transmit pathogens and depends on interactions between pathogen and arthropod genetics as well as environmental factors. For arbovirus transmission, the female mosquito ingests viremic blood, the virus infects and replicates in midgut cells, escapes from the midgut, and disseminates to other tissues, including the salivary glands. Virus-laden saliva is then injected into a new host. For transmission to occur, the virus must overcome several "barriers", including barriers to midgut infection and/or escape and salivary infection and/or escape. By examining the spatial/temporal infection dynamics of Culex tarsalis strains infected with western equine encephalomyelitis virus (WEEV), we identified tissue tropisms and potential tissue barriers, and evaluated the effects of viral dose and time postingestion. METHODS: Using immunostained paraffin sections, WEEV antigens were tracked in four Cx. tarsalis strains: two recently colonized California field strains - Coachella Valley, Riverside County (COAV) and Kern National Wildlife Refuge (KNWR); and two laboratory strains selected for WEEV susceptibility (high viremia producer, HVP), and WEEV resistance (WR). RESULTS AND CONCLUSIONS: Tissues susceptible to WEEV infection included midgut epithelium, neural ganglia, trachea, chorionated eggs, and salivary glands. Neuroendocrine cells in the retrocerebral complex were occasionally infected, indicating the potential for behavioral effects. The HVP and COAV strains vigorously supported viral growth, whereas the WR and KNWR strains were less competent. Consistent with earlier studies, WEEV resistance appeared to be related to a dose-dependent midgut infection barrier, and a midgut escape barrier. The midgut escape barrier was not dependent upon the ingested viral dose. Consistent with midgut infection modulation, disseminated infections were less common in the WR and KNWR strains than in the HVP and COAV strains. Once the virus disseminated from the midgut, all strains were able to develop salivary gland infections. The possible roles of observed pathology will be discussed in a subsequent paper.
Full Text Available BACKGROUND: Anopheles sinensis is a competent malaria vector in China. An understanding of vector population structure is important to the vector-based malaria control programs. However, there is no adequate data of A. sinensis population genetics available yet. METHODOLOGY/PRINCIPAL FINDINGS: This study used 5 microsatellite loci to estimate population genetic diversity, genetic differentiation and demographic history of A. sinensis from 14 representative localities in China. All 5 microsatellite loci were highly polymorphic across populations, with high allelic richness and heterozygosity. Hardy-Weinberg disequilibrium was found in 12 populations associated with heterozygote deficits, which was likely caused by the presence of null allele and the Wahlund effect. Bayesian clustering analysis revealed two gene pools, grouping samples into two population clusters; one includes six and the other includes eight populations. Out of 14 samples, six samples were mixed with individuals from both gene pools, indicating the coexistence of two genetic units in the areas sampled. The overall differentiation between two genetic pools was moderate (F(ST = 0.156. Pairwise differentiation between populations were lower within clusters (F(ST = 0.008-0.028 in cluster I and F(ST = 0.004-0.048 in cluster II than between clusters (F(ST = 0.120-0.201. A reduced gene flow (Nm = 1-1.7 was detected between clusters. No evidence of isolation by distance was detected among populations neither within nor between the two clusters. There are differences in effective population size (Ne = 14.3-infinite across sampled populations. CONCLUSIONS/SIGNIFICANCE: Two genetic pools with moderate genetic differentiation were identified in the A. sinensis populations in China. The population divergence was not correlated with geographic distance or barrier in the range. Variable effective population size and other demographic effects of historical population perturbations could be the factors affecting the population differentiation. The structured populations may limit the migration of genes under pressures/selections, such as insecticides and immune genes against malaria.
The roots of Eleutherococcus senticosus, a well-known medicinal plant from Eastern Asia, are used worldwide for their known beneficial medicinal properties. Recently the leaves have been used as an alternative to the roots. The present study was aimed at exploring the leaf essential oil as a potenti...
Full Text Available Abstract Background Agrochemicals have been widely used in Pakistan for several years. This exposes mosquito populations, particularly those present around agricultural settings, to an intense selection pressure for insecticide resistance. The aim of the present study was to investigate the toxicity of representative agrochemicals against various populations of Aedes albopictus (Skuse collected from three different regions from 2008-2010. Results For organophosphates and pyrethroids, the resistance ratios compared with susceptible Lab-PK were in the range of 157-266 fold for chlorpyrifos, 24-52 fold for profenofos, 41-71 fold for triazofos, and 15-26 fold for cypermethrin, 15-53 fold for deltamethrin and 21-58 fold for lambdacyhalothrin. The resistance ratios for carbamates and new insecticides were in the range of 13-22 fold for methomyl, 24-30 fold for thiodicarb, and 41-101 fold for indoxacarb, 14-27 fold for emamectin benzoate and 23-50 fold for spinosad. Pair wise comparisons of the log LC50s of insecticides revealed correlation among several insecticides, suggesting a possible cross resistance mechanism. Moreover, resistance remained stable across 3 years, suggesting field selection for general fitness had also taken place for various populations of Ae. albopictus. Conclusion Moderate to high level of resistance to agrochemicals in Pakistani field populations of Ae. albopictus is reported here first time. The geographic extent of resistance is unknown but, if widespread, may lead to problems in future vector control.
Full Text Available Introducción. Los cultivos celulares de insectos son una metodología útil en estudios biomédicos y tecnológicos. Objetivo. El propósito principal del presente trabajo fue obtener y caracterizar cultivos celulares derivados de tejidos embrionarios de Aedes aegypti. Materiales y métodos. Se emplearon huevos embrionados para los explantes de tejidos en los medios de cultivos MM/VP12 y L-15/Grace, con suplemento de 20% de suero fetal bovino y una mezcla al 1% de antibiótico y antimicótico, con un rango de pH entre 6,8 y 7,0. Los cultivos se incubaron a una temperatura de 28oC sin atmósfera de CO . Resultados. El crecimiento celular se obtuvo en el medio L-15/Grace, 3 semanas después de haber sido sembrados los tejidos embrionarios; sin embargo, se necesitaron 6 meses para la formación de la monocapa confluente. Desde agosto de 2003 hasta junio de 2004, se habían realizado 28 subcultivos. Las células se caracterizaron morfológicamente; predominaron las formas epitelioides en subcultivos de pases altos. También se reconocieron las particularidades morfométricas del cariotipo y, además, se determinaron los perfiles isoenzimáticos y moleculares de los cultivos celulares, los cuales se compararon con muestras de adultos de la especie tomadas de la misma colonia y con líneas celulares derivadas de otros insectos. Discusión. Estas células representan, potencialmente, un importante sistema in vitro en investigaciones básicas y aplicadas.
Guedes, Duschinka R D; Gomes, Elisete T B; Paiva, Marcelo H S; Melo-Santos, Maria A V de; Alves, Joana; Gómez, Lara F; Ayres, Constância F J
Arthropod-borne viruses, such as Dengue (DENV), Chikungunya (CHIKV), and Zika (ZIKV), pose a challenge to public health, due to their worldwide distribution and large-scale outbreaks. Dengue fever is currently one of the most important diseases and it is caused by four serotypes of DENV and is mainly transmitted by the mosquito Aedes aegypti. It is estimated that 50-100 million cases are reported every year worldwide. More recently, CHIKV and ZIKV, which are also transmitted by Ae. aegypti, have caused epidemics in countries in the Caribbean region, the Pacific region, and Americas. Cabo Verde faced its first dengue outbreak in 2009, with more than 21,000 reported cases and four registered deaths. The epidemic was caused by DENV-3 transmitted by Ae. aegypti mosquitoes. In addition, the country faced a Zika outbreak with more than 7,500 notified cases from October 2015 to May 2016. In the present study, we conducted a survey in mosquito samples to detect arboviruses circulating in the local vector population. Collections were performed from November 2014 to January 2015, in the City of Praia, the capital of Cabo Verde, using aspirators and BG-sentinel traps. Samples were examined by multiplex Reverse Transcription-polymerase chain reaction. A total of 161 Ae. aegypti adult females were analyzed (34 pools) and from these samples, eight pools were found positive for DENV-2 and DENV-4. Our results revealed a very high natural infection rate in the vector population and showed two different serotypes co-circulating in the island that differ from the one detected in the 2009 outbreak in Cabo Verde. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.
Mboera, L.E.G.; Takken, W.; Mdira, K.Y.; Pickett, J.A.
The effectiveness of traps baited with (5R,6S)-6-acetoxy-5-hexadecanolide (the synthetic oviposition pheromone) and grass infusions in sampling a population of gravid Culex quinquefasciatus Say was conducted in Muheza, Northeast Tanzania. A counterflow geometry (CFG) trap baited with pheromone and
Mohamad, N; Zuharah, W F
Toxorhynchites splendens larvae are a natural predator of dengue vector mosquito larvae, Aedes albopictus. This study was carried out to evaluate the predation rate of Tx. splendens third instar larvae on Ae. albopictus larvae in 24 h. Each predator was offered prey at a density between 10 to 50 individuals. Predation rate of Tx. splendens were also tested with two manipulated factors; various types of container and different water volumes. The experiment was evaluated in man-made containers (tin cans, plastic drinking glasses and rubber tires) and natural container (bamboo stumps) which were filled with different water volumes (full, half full, 1/4 full, and 1/8 full). The prey density and the characteristics of the container were found as significant factors which influence the predation rate of Tx. splendens. The predator consumed significantly more prey at higher prey densities (40 and 50 preys) compared to the lowest density (10 preys) (F=3.935, df=4, p=0.008). The results showed significantly higher consumption in horizontal shaped container of rubber tire than in vertical shape of bamboo stumps (F=3.100, df=3, p=0.029). However, the water volume had no significant effect on predation rate of Tx. splendens (F=1.736, df=3, p=0.162). We generally suggest that Tx. splendens is best to be released in discarded tires or any other containers with horizontal shape design with wide opening since Tx. splendens can become more effective in searching prey in this type of container design. This predator is also a suitable biocontrol candidates to be introduced either in wet and dry seasons in Malaysia.
Mukabana Wolfgang R
Full Text Available Abstract Background The development and implementation of innovative vector control strategies for malaria control in Africa requires in-depth ecological studies in contained semi-field environments. This particularly applies to the development and release of genetically-engineered vectors that are refractory to Plasmodium infection. Here we describe a modified greenhouse, designed to simulate a natural Anopheles gambiae Giles ecosystem, and the first successful trials to complete the life-cycle of this mosquito vector therein. Methods We constructed a local house, planted crops and created breeding sites to simulate the natural ecosystem of this vector in a screen-walled greenhouse, exposed to ambient climate conditions, in western Kenya. Using three different starting points for release (blood-fed females, virgin females and males, or eggs, we allowed subsequent stages of the life-cycle to proceed under close observation until one cycle was completed. Results Completion of the life-cycle was observed in all three trials, indicating that the major life-history behaviours (mating, sugar feeding, oviposition and host seeking occurred successfully. Conclusion The system described can be used to study the behavioural ecology of laboratory-reared and wild mosquitoes, and lends itself to contained studies on the stability of transgenes, fitness effects and phenotypic characteristics of genetically-engineered disease vectors. The extension of this approach, to enable continuous maintenance of successive and overlapping insect generations, should be prioritised. Semi-field systems represent a promising means to significantly enhance our understanding of the behavioural and evolutionary ecology of African malaria vectors and our ability to develop and evaluate innovative control strategies. With regard to genetically-modified mosquitoes, development of such systems is an essential prerequisite to full field releases.
Neves, David Pereira; Silva, Rivany Fernandes da
After the Aedees albopictus has been discoved by Neves & Espinola (1987) at Minas Gerais state, we begun studying some biologic aspects, such as breeding places, host preference, times of feeding and the preferred places for blood feeding.
Knols Bart GJ
Full Text Available Abstract Background Anopheles gambiae Giles is the most important vector of human malaria in sub-Saharan Africa. Knowledge of the factors that influence its daily oviposition pattern is crucial if field interventions targeting gravid females are to be successful. This laboratory study investigated the effect of oviposition substrate and time of blood feeding on daily oviposition patterns of An. gambiae mosquitoes. Methods Greenhouse-reared gravid and hypergravid (delayed oviposition onset An. gambiae sensu stricto and wild-caught An. gambiae sensu lato were exposed to three types of substrates in choice and no-choice cage bioassays: water from a predominantly anopheline colonised ground pool (anopheline habitat water, swamp water mainly colonised by culicine larvae (culicine habitat water and distilled water. The daily oviposition pattern and the number of eggs oviposited on each substrate during the entire egg-laying perio