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Sample records for culex salinarius coquillett

  1. Redescription of the pupa of Culex salinarius Coquillett and comparison with Culex nigripalpus Theobald.

    Science.gov (United States)

    Darsie, Richard F; Day, Jonathan F

    2006-09-01

    The pupa of Culex salinarius is redescribed with updated chaetotaxal nomenclature and a full illustration. The pupal chaetotaxy of Cx. salinarius and the similar species Culex nigripalpus is compared.

  2. Studies of the genus Culex linnaeus in Florida. III. Redescription of the fourth-stage larva of Culex salinarius Coquillett and comparison with that of Cx. nigripalpus Theobald.

    Science.gov (United States)

    Darsie, Richard F; Almasi, James R; Day, Jonathan F

    2006-06-01

    The larva of Culex salinarius is completely described and illustrated, except for the mouth parts, and compared with morphologically similar larva of Cx. nigripalpus. At least 8 characters have been found to separate larvae of the two species of which 7 give 90% or higher divergence while the remaining character gives 87% separation.

  3. Salt marsh as Culex salinarius larval habitat in coastal New York.

    Science.gov (United States)

    Rochlin, Ilia; Dempsey, Mary E; Campbell, Scott R; Ninivaggi, Dominick V

    2008-09-01

    Culex salinarius is considered one of the most likely bridge vectors involved in the human transmission cycle of West Nile virus (WNV) and eastern equine encephalomyelitis virus (EEEV) in the northeastern USA. The larval habitats of this species in the coastal region of New York State are currently poorly known. Between 2005 and 2007, a larval survey was carried out to identify and characterize possible larval habitats in Suffolk County, encompassing natural and man-made freshwater wetlands, artificial containers, and salt marshes. Only relatively undisturbed salt marsh yielded Cx. salinarius larvae in considerable numbers from several sites over a period of 2 years. The immature stages of this species were found associated with Spartina patens and S. alterniflora of the upper marsh at salinities ranging from 4.3 to 18.8 parts per thousand. Both heavily impacted and relatively undisturbed salt marshes produced several hundreds of adult Cx. salinarius per Centers for Disease Control and Prevention (CDC) light trap per night, an order of magnitude higher than CDC light traps deployed at upland sites. The ability of Cx. salinarius to use both heavily impacted and relatively undisturbed salt marshes for reproduction has significant repercussions for marsh restoration and vector control practices.

  4. Host-feeding habits of Culex and other mosquitoes (Diptera: Culicidae) in the Borough of Queens in New York City, with characters and techniques for identification of Culex mosquitoes.

    Science.gov (United States)

    Apperson, Charles S; Harrison, Bruce A; Unnasch, Thomas R; Hassan, Hassan K; Irby, William S; Savage, Harry M; Aspen, Stephen E; Watson, D Wesley; Rueda, Leopoldo M; Engber, Barry R; Nasci, Roger S

    2002-09-01

    The host-feeding patterns of mosquitoes (n = 247) collected in the Borough of Queens in New York City in July and August 2000 were investigated using an indirect ELISA and a polymerase chain reaction (PCR)-heteroduplex assay. Culex pipiens L. and Cx. restuans Theobald fed primarily on birds, and their feeding habits support their implication as enzootic vectors of West Nile virus. Culex salinarius Coquillett and Coquillettidia perturbans (Walker) fed mainly on mammals, with fewer blood meals taken from birds, and these two species are potential bridge vectors of West Nile virus. Culex mosquitoes took blood meals (n = 54) from 11 different avian species. Only the northern cardinal (Cardinalis cardinalis), American robin (Turdus migratorius), and Brown-headed cow bird (MolIothrus ater) were fed upon by all three Culex species. Multiple blood feedings on avian hosts were detected in Cx. pipiens and Cx. restuans. Species identifications of Culex mosquitoes made using morphological characteristics were confirmed with a PCR assay that employed species-specific primers. All Cx. pipiens (n = 20) and Cx. salinarius (n = 10) specimens were correctly identified, but three (20%) of 15 Cx. restuans were misidentified as Cx. pipiens.

  5. Host feeding patterns of Culex mosquitoes (Diptera: Culicidae) in East Baton Rouge Parish, Louisiana.

    Science.gov (United States)

    Mackay, Andrew J; Kramer, Wayne L; Meece, Jennifer K; Brumfield, Robb T; Foil, Lane D

    2010-03-01

    Host feeding patterns were examined for four species of Culex mosquitoes collected from 18 sites in or adjacent to East Baton Rouge Parish, LA, from November 2002 to October 2004. Host DNA from 37 bloodfed Culex coronator Dyar and Knab, 67 bloodfed Cx. salinarius Coquillett, 112 bloodfed Cx. nigripalpus Theobald, and 684 bloodfed Cx. quinquefasciatus Say were identified. The percentages of bloodmeals containing mammalian DNA were 94.6% for Cx. coronator, 82.1% for Cx. salinarius, 66.1% for Cx. nigripalpus, and 40.1% for Cx. quinquefasciatus. Human DNA was detected in 7% of the bloodmeals from Cx. quinquefasciatus and 2.7% of the bloodmeals from Cx. nigripalpus. The northern cardinal was the most frequent avian host of Cx. quinquefasciatus and Cx. nigripalpus. In 2003 and 2004, there was no significant relationship from May through October between the proportion of Cx. quinquefasciatus feeding on mammalian hosts and the date of collection. Of the six avian species most frequently fed on by Cx. quinquefasciatus, the northern cardinal, northern mockingbird, common grackle, and brown thrasher were fed on more frequently than expected based on their abundance. House sparrows were fed on less frequently than expected based on their abundance. These data support the conclusions of previous studies that Cx. quinquefasciatus is the most important vector for both the enzootic amplification and transmission of West Nile virus to humans in southern Louisiana.

  6. Vector competence of selected North American Culex and Coquillettidia mosquitoes for West Nile virus.

    OpenAIRE

    Sardelis, M. R.; Turell, M.J.; Dohm, D. J.; O'Guinn, M. L.

    2001-01-01

    To control West Nile virus (WNV), it is necessary to know which mosquitoes are able to transmit this virus. Therefore, we evaluated the WNV vector potential of several North American mosquito species. Culex restuans and Cx. salinarius, two species from which WNV was isolated in New York in 2000, were efficient laboratory vectors. Cx. quinquefasciatus and Cx. nigripalpus from Florida were competent but only moderately efficient vectors. Coquillettidia perturbans was an inefficient laboratory v...

  7. Vector competence of selected North American Culex and Coquillettidia mosquitoes for West Nile virus.

    Science.gov (United States)

    Sardelis, M R; Turell, M J; Dohm, D J; O'Guinn, M L

    2001-01-01

    To control West Nile virus (WNV), it is necessary to know which mosquitoes are able to transmit this virus. Therefore, we evaluated the WNV vector potential of several North American mosquito species. Culex restuans and Cx. salinarius, two species from which WNV was isolated in New York in 2000, were efficient laboratory vectors. Cx. quinquefasciatus and Cx. nigripalpus from Florida were competent but only moderately efficient vectors. Coquillettidia perturbans was an inefficient laboratory vector. As WNV extends its range, exposure of additional mosquito species may alter its epidemiology.

  8. Redescription of larva, pupa and imago male of Chironomus (Chironomus) salinarius Kieffer from the saline rivers of the Lake Elton basin (Russia), its karyotype and ecology.

    Science.gov (United States)

    Orel Zorina, Oksana V; Istomina, Albina G; Kiknadze, Iya I; Zinchenko, Tatiana D; Golovatyuk, Larisa V

    2014-07-29

    Cytology and ecology of Chironomus (Chironomus) salinarius Kieffer, 1915 (Diptera, Chironomidae) was examined from material collected in the saline rivers of the Lake Elton basin (Volgograd region, Russia). Larvae of salinarius-type were identified as C. salinarius on the basis of their karyotype. The species is redescribed on the basis of all metamorphic stages. The reared imago and karyotype were obtained from larvae of the same population. The karyotype of C. salinarius, detailed mapping of the 5 chromosome arms A, C, D, E, F and characteristics of chromosome polymorphism are provided. Information on distribution and ecology of C. salinarius from the saline rivers (total mineralization 6.8-31.6 g l-1) of the Lake Elton basin is also given. Chironomus salinarius is a common in the saline rivers and occurs in sediments with high silt content. On the basis of recent samplings C. salinarius appears to be very abundant in saline, mesotrophic as well as in eutrophic rivers. Chironomus salinarius accounted for 49-66% of total abundance of zoobenthos in water with salinity up to 13-31.6 g l-1.

  9. Modeling/GIS, Risk Assessment, Economic Impact: Seasonal Patterns for Entomological Measures of Risk for Exposure to Culex Vectors and West Nile Virus in Relation to Human Disease Cases in Northeastern Colorado

    OpenAIRE

    Bolling, Bethany G.; Barker, Christopher M.; Moore, Chester G.; Pape, W. John; Eisen, Lars

    2009-01-01

    We examined seasonal patterns for entomological measures of risk for exposure to Culex vectors and West Nile virus (family Flaviviridae, genus Flavivirus, WNV) in relation to human WNV disease cases in a five-county area of northeastern Colorado during 2006–2007. Studies along habitat/elevation gradients in 2006 showed that the seasonal activity period is shortened and peak numbers occur later in the summer for Culex tarsalis Coquillett females in foothills-montane areas >1,600 m compared wit...

  10. Mitochondrial genomes and comparative analyses of Culex camposi, Culex coronator, Culex usquatus and Culex usquatissimus (Diptera:Culicidae), members of the coronator group

    National Research Council Canada - National Science Library

    Demari-Silva, Bruna; Foster, Peter G; de Oliveira, Tatiane M P; Bergo, Eduardo S; Sanabani, Sabri S; Pessôa, Rodrigo; Sallum, Maria Anice M

    2015-01-01

    The Coronator Group currently encompasses six morphologically similar species (Culex camposi Dyar, Culex coronator Dyar and Knab, Culex covagarciai Forattini, Culex usquatus Dyar, Culex usquatissimus Dyar, and Culex ousqua Dyar...

  11. New species of Metatrichia Coquillett (Diptera: Scenopinidae) from Australia and Venezuela

    Science.gov (United States)

    Two new species of the cosmopolitan genus Metatrichia Coquillett are described. Metatrichia dhimurru sp. nov. is described from Arnhem Land (Northern Territory), Australia and represents the third species of the genus to be described from the Australian-Papuan region. Metatrichia venezuelensis sp. n...

  12. Ovicidal activity of neem products (azadirachtin) against Culex tarsalis and Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Su, T; Mulla, M S

    1998-06-01

    Bioactive compounds contained in the seed kernel and other parts of the neem tree (Azadirachta indica A. Juss) have been found to show insecticidal activities and other effects in many species of insects. These activities include antifeedancy, growth regulation, fecundity suppression, male sterility, oviposition repellency, changes in biological fitness such as loss of flying ability, immunodepression, enzyme inhibition, splitting of biological rhythms, and so forth. We investigated the ovicidal effects of various formulations of azadrirachtin (AZ) against the mosquitoes Culex tarsalis Coquillett and Culex quinquefasciatus Say. The formulations tested were wettable powder Azad WP10, emulsifiable concentrate Azad EC4.5, and technically pure AZ. The ovicidal activity of the test neem products was influenced by concentration of AZ, age of the egg rafts, and age of the neem preparations. Other factors such as formulation and mosquito species were also involved in the degree of ovicidal activity. When the egg rafts were deposited directly in fresh neem suspension and left there for 4 h before transfer to untreated water, 1 ppm of AZ produced almost 100% mortality in eggs. When egg rafts aged for 0, 4, 8, 12, and 24 h were exposed to 10 ppm neem suspensions for 36 h, the ovicidal activity was only attained in the egg rafts deposited directly (0 h old) in the neem suspension, not in those with ages of 4-24 h. On aging, depending on the formulations and mosquito species, the neem suspensions at 1 ppm completely lost ovicidal activity within 7-20 days. The egg rafts of Cx. quinquefasciatus were more susceptible to the test neem products than those of Cx. tarsalis. The formulated neem products were more persistent and effective than the technical AZ. The wettable powder (WP) formulation was slightly more persistent and effective than the emulsifiable concentrate (EC). The ovicidal activity of the neem products against mosquitoes from the current research clearly demonstrated

  13. Experimental and natural vertical transmission of West Nile virus by California Culex (Diptera: Culicidae) mosquitoes.

    Science.gov (United States)

    Nelms, Brittany M; Fechter-Leggett, Ethan; Carroll, Brian D; Macedo, Paula; Kluh, Susanne; Reisen, William K

    2013-03-01

    Culex (Diptera: Culicidae) mosquitoes, the primary summer vectors of West Nile virus (family Flaviviridae, genus Flavivirus, WNV), also may serve as overwintering reservoir hosts. Detection of WN viral RNA from larvae hatched from eggs deposited by infected females during late summer and fall may provide evidence for the vertical passage of WNV to overwintering cohorts. To determine whether vertical transmission to the overwintering generation occurs in populations of Culex mosquitoes throughout California, larvae from naturally infected females were tested by family for WN viral RNA by real-time quantitative reverse transcription-polymerase chain reaction during August through October 2011. Viral RNA was detected in 34 of 934 Culex tarsalis Coquillett and Cx. pipiens complex females that laid viable egg rafts. From these egg rafts, first-instar larvae from nine families tested positive, yielding an overall field vertical transmission rate of 26% (n = 34). To determine whether the WNV may be lost transtadially during development to the adult stage, first-instar larvae and adult progeny from experimentally infected Cx. pipiens complex females were assessed for the presence and quantity of WN viral RNA. Most (approximately 75%) WNV infections were lost from positive families during larval development to the adult stage. In field and laboratory studies, only infected mothers with mean cycle threshold scores Culex mosquitoes collected throughout California during late summer and fall, with females having high titered infections capable of passing WNV onto their progeny destined for overwintering.

  14. The effect of predatory fish exudates on the ovipostional behaviour of three mosquito species: Culex quinquefasciatus, Aedes aegypti and Culex tarsalis.

    Science.gov (United States)

    Van Dam, A R; Walton, W E

    2008-12-01

    Three mosquito species, Culex tarsalis Coquillett, Culex quinquefasciatus Say and Aedes aegypti L. (Diptera: Culicidae), were examined in laboratory binary choice experiments to investigate whether fish exudates from the mosquitofish, Gambusia affinis (Baird & Girard) (Cyprinodontiformes: Poecilliidae), deter oviposition and whether the responses of these mosquito species to fish exudates in oviposition sites are consistent with the risk of predation from fish experienced by each species in their respective natural breeding habitats. Culex tarsalis was deterred significantly from egg laying by the presence of fish exudates in oviposition cups, consistent with high levels of predation by fish in natural breeding sites. Egg laying by Cx quinquefasciatus was slightly reduced in water with fish exudates, but was not consistently deterred by water conditioned by mosquitofish, consistent with the species' relatively low risk of fish predation in natural habitats. Oviposition by container-breeding Ae. aegypti was not deterred by the presence of fish exudates in oviposition cups, consistent with a low risk of predation by fish in natural habitats.

  15. Vector competence of Culex tarsalis from Orange County, California, for West Nile virus.

    Science.gov (United States)

    Turell, Michael J; O'Guinn, Monica L; Dohm, David J; Webb, James P; Sardelis, Michael R

    2002-01-01

    To evaluate the vector competence of Culex tarsalis Coquillett for West Nile virus (WN), females reared from larvae collected in Huntington Beach, Orange County, CA, were fed on 2-3-day-old chickens previously inoculated with a New York strain (Crow 397-99) of WN. The Cx. tarsalis mosquitoes were efficient laboratory vectors of WN, with estimated transmission rates of 81% and 91% for mosquitoes that ingested 10(6.5) or 10(7.3) plaque-forming units of WN/mL of blood, respectively. Based on efficiency of viral transmission and the role of this species in the transmission of the closely related St. Louis encephalitis virus, Cx. tarsalis should be considered a potentially important vector of WN in the western United States.

  16. Overwintering Biology of Culex (Diptera: Culicidae) Mosquitoes in the Sacramento Valley of California

    Science.gov (United States)

    NELMS, BRITTANY M.; MACEDO, PAULA A.; KOTHERA, LINDA; SAVAGE, HARRY M.; REISEN, WILLIAM K.

    2014-01-01

    At temperate latitudes, Culex (Diptera: Culicidae) mosquitoes typically overwinter as adult females in reproductive arrest and also may serve as reservoir hosts for arboviruses when cold temperatures arrest viral replication. To evaluate their role in the persistence of West Nile virus (WNV) in the Sacramento Valley of California, the induction and termination of diapause were investigated for members of the Culex pipiens (L.) complex, Culex tarsalis Coquillett, and Culex stigmatosoma Dyar under field, seminatural, and experimental conditions. All Culex spp. remained vagile throughout winter, enabling the collection of 3,174 females and 1,706 males from diverse habitats during the winters of 2010–2012. Overwintering strategies included both quiescence and diapause. In addition, Cx. pipiens form molestus Forskäl females remained reproductively active in both underground and aboveground habitats. Some blood-fed, gravid, and parous Cx. tarsalis and Cx. pipiens complex females were collected throughout the winter period. Under both field and experimental conditions, Cx. tarsalis and Cx. stigmatosoma females exposed to autumnal conditions arrested primary follicular maturation at previtellogenic stage I, with primary to secondary follicular ratios <1.5 (indicative of a hormonally induced diapause). In contrast, most Cx. pipiens complex females did not enter reproductive diapause and ovarian follicles matured to ≥stage I–II (host-seeking arrest) or were found in various stages of degeneration. Diapause was initiated in the majority of Cx. tarsalis and Cx. stigmatosoma females by mid-late October and was terminated after the winter solstice, but host-seeking seemed limited by temperature. An accrual of 97.52 ± 30.7 and 162.85 ± 79.3 degree-days after the winter solstice was estimated to be necessary for diapause termination in Cx. tarsalis under field and seminatural conditions, respectively. An increase in the proportion of blood-fed Culex females in resting

  17. New species and records of Pseudacteon Coquillett, 1907 (Diptera, Phoridae), parasitoids of the fire ant Solenopsis geminata group (Hymenoptera, Formicidae).

    Science.gov (United States)

    Pereira, Thalles Platiny Lavinscky; Delabie, Jacques Hubert Charles; Bravo, Freddy

    2015-09-29

    The genus Pseudacteon Coquillett (Diptera, Phoridae) has a worldwide distribution and comprises parasitic myrmecophilous species that decapitate host ants. Seventy one species are known in the genus, 41 of them occur in the Neotropical Region and are 25 from Brazil. In northeastern Brazil, there are only records for two species, Pseudacteon dentiger Borgmeier and Pseudacteon antiguensis Malloch. In this paper, two new species of the genus are described from female specimens, Pseudacteon pesqueroi new spec. and Pseudacteon plowesi new spec., and also, new records of three Pseudacteon species for the Brazilian Northeast are given.

  18. Relative incidence of Bactrocera cucurbitae (Coquillett) and Dacus ciliatus Loew on cucurbitaceous vegetables

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, N.K. Krishna; Verghese, Abraham; Shivakumara, B.; Krishnamoorthy, P.N.; Ranganath, H.R. [Indian Institute of Horticultural Research, Bangalore (India). Div. of Entomology and Nematology

    2006-07-01

    The melon fly, Bactrocera cucurbitae (Coquillett) is a major pest of cucurbitaceous vegetables and fruits in many parts of the world. Infestation of an another species, the lesser pumpkin fly, Dacus ciliatus Loew is reported on a few cucurbits in the Indian sub-continent and Africa. While extensive work on seasonality, infestation percent, host preference, attraction to para pheromone on B. cucurbitae has been reported, little is known of D. ciliatus. Field experiments were carried out at the Indian Institute of Horticultural Research (IIHR), Bangalore (12058'N; 77035'E) from June 2002- October 2003. Cucumber (Cucumis sativus L), ridge gourd (Luffa acutangula (L.) Roxb), bitter gourd (Momordica charantia L.) and pickling cucumbers [C. sativus L (variety. Ijax)] were raised at monthly interval. Cue lure baited bottle traps were hung to monitor B. cucurbitae and other related species. Bactrocera cucurbitae was present all through the year and maximum number of adults was trapped during August (14.14/trap/week). Dacus ciliatus was trapped only from May to October but in relatively less numbers ({approx} 1/week). Maximum fruit fly infestation was 77.03 % on bitter gourd (August 2003), 75.65 % on ridge gourd (Nov. 02), 73.83 % on cucumber (October, 02) and 63.31 % on pickling cucumber (October, 02). Trap catches of B. cucurbitae was significantly and positively correlated with relative humidity. Maximum and minimum temperature, RH (%), rainfall (mm), evaporation (mm) and wind speed (km/h) collectively determined 44 % of B. cucurbitae trap catches. Maximum fruit fly emergence of 494.64/ kg fruit was on bitter gourd (October, 2002) followed by cucumber (431.97, November, 2002), pickling cucumber (307.51, October 2002) and ridge gourd (210.74, October, 2003). Dacus ciliatus formed only 4.5% of the total number of fruit flies on bitter gourd and 0.2% on pickling cucumber. Its infestation was not observed on cucumber and ridge gourd. Parasitism by the larval

  19. West Nile virus infection decreases fecundity of Culex tarsalis females.

    Science.gov (United States)

    Styer, Linda M; Meola, Mark A; Kramer, Laura D

    2007-11-01

    West Nile virus (family Flaviviridae, genus Flavivirus, WNV) persistently infects many mosquito tissues, and it has been associated with cytopathological changes in midgut muscles and salivary glands. However, the effects of WNV infection on mosquito fitness (survival and reproduction) are not known. We conducted a life table study of individually housed female Culex tarsalis Coquillett. After an initial bloodmeal from a WNV-infected or uninfected chicken, mosquitoes were provided sucrose and offered weekly opportunities to feed on a hanging blood drop. WNV transmission status was determined by testing the remaining blood drop for virus after mosquito feeding. Dead mosquitoes and eggs were collected daily. Mosquito legs and bodies were tested for WNV, and eggs were counted and allowed to hatch. Two replicates of this experiment were performed, with a total of 62 mosquitoes that fed on a WNV-infected chicken (of which 21 became infected) and 43 mosquitoes that fed on an uninfected chicken. Fecundity of WNV-infected mosquitoes was significantly lower than that of uninfected mosquitoes, especially during the first oviposition. WNV infection was associated with smaller egg rafts, whereas increasing wing length and WNV titer in the legs had a positive effect on egg raft size. Additionally, infected mosquitoes had lower egg hatch rates than did uninfected mosquitoes. There were no significant differences in survival between infected and uninfected mosquitoes. Blood feeding rates were higher in infected mosquitoes than in uninfected mosquitoes. A small amount of virus (average, 378; range, 5-5000 plaque-forming units) was transmitted to the blood drops fed upon by infected mosquitoes. Although WNV infection negatively impacts mosquito reproduction, facets of mosquito biology that are critical to virus transmission success were either not affected (survival) or changed in such a way as to result in enhanced vectorial capacity (blood feeding).

  20. Multi-scale approach to the environmental factors effects on spatio-temporal variability of Chironomus salinarius (Diptera: Chironomidae) in a French coastal lagoon

    Science.gov (United States)

    Cartier, V.; Claret, C.; Garnier, R.; Fayolle, S.; Franquet, E.

    2010-03-01

    The complexity of the relationships between environmental factors and organisms can be revealed by sampling designs which consider the contribution to variability of different temporal and spatial scales, compared to total variability. From a management perspective, a multi-scale approach can lead to time-saving. Identifying environmental patterns that help maintain patchy distribution is fundamental in studying coastal lagoons, transition zones between continental and marine waters characterised by great environmental variability on spatial and temporal scales. They often present organic enrichment inducing decreased species richness and increased densities of opportunist species like C hironomus salinarius, a common species that tends to swarm and thus constitutes a nuisance for human populations. This species is dominant in the Bolmon lagoon, a French Mediterranean coastal lagoon under eutrophication. Our objective was to quantify variability due to both spatial and temporal scales and identify the contribution of different environmental factors to this variability. The population of C. salinarius was sampled from June 2007 to June 2008 every two months at 12 sites located in two areas of the Bolmon lagoon, at two different depths, with three sites per area-depth combination. Environmental factors (temperature, dissolved oxygen both in sediment and under water surface, sediment organic matter content and grain size) and microbial activities (i.e. hydrolase activities) were also considered as explanatory factors of chironomid densities and distribution. ANOVA analysis reveals significant spatial differences regarding the distribution of chironomid larvae for the area and the depth scales and their interaction. The spatial effect is also revealed for dissolved oxygen (water), salinity and fine particles (area scale), and for water column depth. All factors but water column depth show a temporal effect. Spearman's correlations highlight the seasonal effect

  1. Vector Competence and Capacity of Culex erraticus (Diptera: Culicidae) for Eastern Equine Encephalitis Virus in the Southeastern United States.

    Science.gov (United States)

    Bingham, Andrea M; Burkett-Cadena, Nathan D; Hassan, Hassan K; Unnasch, Thomas R

    2016-03-01

    Field studies of the ecology of eastern equine encephalitis virus (EEEV; family Togaviridae, genus Alphavirus) in the southeastern United States have demonstrated that Culex erraticus (Dyar and Knab) is the most common mosquito at many enzootic sites and is often infected with the virus. However, the competence of Cx. erraticus for EEEV has not been explored in detail. Culex erraticus females were collected from the field and fed upon EEEV-infected chicks. The infected mosquitoes were provided honey for nutrition and to monitor for time to infectiveness. Of the mosquitoes that survived the 14-d postfeeding period, 89% were infected and 84% had evidence of a disseminated infection, though titers were generally low. EEEV was first detected in honey 6 d postinfection and was detected in samples collected from 94% of the mosquitoes with a disseminated infection overall. These data and others were then employed to estimate the relative vectorial capacity of Cx. erraticus at an EEEV enzootic site in Alabama. The vectorial capacity of Cx. erraticus at this site was 44% of Culiseta melanura (Coquillett), the accepted enzootic vector, suggesting Cx. erraticus may play a role in transmitting EEEV in areas where it is abundant and Cs. melanura rare.

  2. Culex (Culex) declarator, a mosquito species new to Florida.

    Science.gov (United States)

    Darsie, Richard F; Shroyer, Donald A

    2004-09-01

    One specimen of a mosquito new to Florida, Culex declarator, was first found in 1998 in Indian River County. A 2nd specimen was collected in 2002. Beginning in September 2003, Cx. declarator adults were regularly encountered in routine mosquito surveillance sampling, with more than 300 specimens appearing in 45 collections. Prior to our find, the U.S. distrubution was thought to be restricted to south Texas. The full extent of this species' distribution in Florida has yet to be determined.

  3. Larvicidal activity of extracts of Ginkgo biloba exocarp for three different strains of Culex pipiens pallens.

    Science.gov (United States)

    Sun, Lixin; Dong, Huiqin; Guo, Chongxia; Qian, Jin; Sun, Jing; Ma, Lei; Zhu, Changliang

    2006-03-01

    Ethanolic extracts from the Ginkgo biloba L. exocarp from the Chinese ginkgo were assayed against larvae of three strains of Culex pipiens pallens Coquillett. The chemical compositions were detected using a Hewlett-Packard 6890/5973 mass spectrometric detector. The larvicidal bioassay was carried out according to the recommendations of the World Health Organization. The analysis of the essential oil of ginkgo exocarp showed that its major components are ginkgo acid (85.3%) and ginkgo phenolic (5.69%). The larvicidal bioassay showed that extracts of ginkgo exocarp have LC50 of 18.6, 12.7, and 25.0 mg/liter for deltamethrin-susceptible, deltamethrin-resistant, and field strains, respectively. The acute toxicity concentrations of the ginkgo extracts that killed 50% (LD50) of Wistar rats within 2 wk and young carp within 96 h were 4947.2 mg/kg and 557.9 mg/liter, respectively. These results are promising in creating new, effective, and affordable approaches to mosquito control.

  4. Seasonal patterns for entomological measures of risk for exposure to Culex vectors and West Nile virus in relation to human disease cases in northeastern Colorado.

    Science.gov (United States)

    Bolling, Bethany G; Barker, Christopher M; Moore, Chester G; Pape, W John; Eisen, Lars

    2009-11-01

    We examined seasonal patterns for entomological measures of risk for exposure to Culex vectors and West Nile virus (family Flaviviridae, genus Flavivirus, WNV) in relation to human WNV disease cases in a five-county area of northeastern Colorado during 2006-2007. Studies along habitat/elevation gradients in 2006 showed that the seasonal activity period is shortened and peak numbers occur later in the summer for Culex tarsalis Coquillett females in foothills-montane areas >1600 m compared with plains areas Studies in the plains of northeastern Colorado in 2007 showed that seasonal patterns of abundance for Cx. tarsalis and Culex pipiens L. females differed in that Cx. tarsalis reached peak abundance in early July (mean of 328.9 females per trap night for 18 plains sites), whereas the peak for Cx. pipiens did not occur until late August (mean of 16.4 females per trap night). During June-September in 2007, which was a year of intense WNV activity in Colorado with 578 reported WNV disease cases, we recorded WNV-infected Cx. tarsalis females from 16 of 18 sites in the plains. WNV infection rates in Cx. tarsalis females increased gradually from late June to peak in mid-August (overall maximum likelihood estimate for WNV infection rate of 8.29 per 1000 females for the plains sites in mid-August). No WNV-infected Culex mosquitoes were recorded from sites >1600 m. The vector index for abundance of WNV-infected Cx. tarsalis females for the plains sites combined exceeded 0.50 from mid-July to mid-August, with at least one site exceeding 1.00 from early July to late August. Finally, we found that abundance of Cx. tarsalis females and the vector index for infected females were strongly associated with weekly numbers of WNV disease cases with onset 4-7 wk later (female abundance) or 1-2 wk later (vector index).

  5. Isotherapic of Culex on the biological cycle of the mosquito Culex sp

    OpenAIRE

    Bruno Reis; Cintia Miranda dos Santos; Patrícia Aparecida Mançano Cavalca; Carlos Moacir Bonato

    2011-01-01

    Introduction: Culex is an insect of the family Culicidae. It occurs in tropical and subtropical regions. It is known as the domestic mosquito. Their larvae develop in stagnant and dirty water, with plenty of organic matter. Some species of the insect such as Culex quinquefasciatus transmit the worms (helminths) called Wuchereria bancrofti filariasis or Elephantiasis. Aims: Thus, the objective of this work was to evaluate the effect of isotherapic of Culex on the biological cycle of...

  6. Culex Species Mosquitoes and Zika Virus.

    Science.gov (United States)

    Huang, Yan-Jang S; Ayers, Victoria B; Lyons, Amy C; Unlu, Isik; Alto, Barry W; Cohnstaedt, Lee W; Higgs, Stephen; Vanlandingham, Dana L

    2016-10-01

    Recent reports of Zika virus (ZIKV) isolates from Culex species mosquitoes have resulted in concern regarding a lack of knowledge on the number of competent vector species for ZIKV transmission in the new world. Although observations in the field have demonstrated that ZIKV isolation can be made from Culex species mosquitoes, the detection of ZIKV in these mosquitoes is not proof of their involvement in a ZIKV transmission cycle. Detection may be due to recent feeding on a viremic vertebrate, and is not indicative of replication in the mosquito. In this study, susceptibility of recently colonized Culex species mosquitoes was investigated. The results showed a high degree of refractoriness among members of Culex pipiens complex to ZIKV even when exposed to high-titer bloodmeals. Our finding suggests that the likelihood of Culex species mosquitoes serving as secondary vectors for ZIKV is very low, therefore vector control strategies for ZIKV should remain focused on Aedes species mosquitoes. Our demonstration that Culex quinquefasciatus from Vero Beach, FL, is refractory to infection with ZIKV is especially important and timely. Based on our data, we would conclude that the autochthonous cases of Zika in Florida are not due to transmission by C. quinquefasciatus, and so control efforts should focus on other species, logically Aedes aegypti and Aedes albopictus.

  7. Enhanced toxicity of binary mixtures of larvicidal constituents from Asarum heterotropoides root to Culex pipiens pallens (Diptera: Culicidae).

    Science.gov (United States)

    Perumalsamy, Haribalan; Kim, Jun-Ran; Kim, Soon-Il; Kwon, Hyung Wook; Ahn, Young-Joon

    2012-01-01

    The toxicity of pellitorine alone or in combination with (-)-asarinin, alpha-asarone, methyleugenol, or pentadecane (1:1, 1:2, 1:3, 2:1, and 3:1 ratios) to third instars from an insecticide-susceptible KS-CP strain and -resistant DJ-CP colony of Culex pipiens pallens Coquillett was evaluated using a direct-contact mortality bioassay. The binary mixture of pellitorine and (-)-asarinin (3:1 ratio) was significantly more toxic against KS-CP larvae (0.95 mg/liter) and DJ-CP larvae (1.07 mg/liter) than either pellitorine (2.08 mg/liter for KS-CP and 2.33 mg/liter for DJ-CP) or (-)-asarinin (11.45 and 12.61 mg/liter) alone. The toxicity of the other binary mixtures (1:1, 1:2, 1:3, and 2:1 ratios) and pellitorine did not differ significantly from each other. Based on the co-toxicity coefficient (CC) and synergistic factor (SF), the three binary mixtures (1:3, 2:1, and 3:1) operated synergistically (CC, 250-390 and SF, 1.4-2.2 for KS-CP; CC, 257-279 and SF, 1.1-2.1 for DJ-CP). The binary mixtures of pellitorine and (-)-asarinin merit further study as potential larvicides for the control of insecticide-resistant mosquito populations.

  8. Predicting weekly variation of Culex tarsalis (Diptera: Culicidae) West Nile virus infection in a newly endemic region, the Canadian prairies.

    Science.gov (United States)

    Chen, Chen-Chih; Epp, Tasha; Jenkins, Emily; Waldner, Cheryl; Curry, Philip S; Soos, Catherine

    2012-09-01

    West Nile virus (WNV) spread across most of North America within a short time period after its incursion into the Western Hemisphere. The Canadian prairies had the highest human incidence of WNV disease in Canada, particularly in 2007. Statistical modeling and geographic information systems can be used to develop a predictive model and facilitate the mobilization of targeted disease management strategies. Using data collected between 2005 and 2008, we constructed models integrating abiotic and biotic factors to predict the WNV infection rate in female Culex tarsalis Coquillett, the primary vector of WNV in the Canadian prairies. During the study period, the highest mean Cx. tarsalis infection rate was during week 34 (late August). The Cx. tarsalis infection rate increased with increasing Cx. tarsalis abundance and mean temperature lagged from 1 to 8 wk, but decreased with increasing mean precipitation lagged from 2 to 6 wk. Furthermore, precipitation was a 'distorter variable' that altered the association between Cx. tarsalis abundance and the WNV infection rate. Our model clarified how weather influenced the Cx. tarsalis infection rate in the Canadian prairies, a newly and highly WNV endemic region of North America. An understanding of the role of lagged weather variables was essential for providing sufficient lead time to predict WNV occurrence, and for implementing disease control and prevention strategies. Furthermore, it is a useful tool for assessing the potential effects of future climate change on WNV in areas near its northern distributional limit.

  9. Modeling Monthly Variation of Culex tarsalis (Diptera: Culicidae Abundance and West Nile Virus Infection Rate in the Canadian Prairies

    Directory of Open Access Journals (Sweden)

    Philip S. Curry

    2013-07-01

    Full Text Available The Canadian prairie provinces of Alberta, Saskatchewan, and Manitoba have generally reported the highest human incidence of West Nile virus (WNV in Canada. In this study, environmental and biotic factors were used to predict numbers of Culex tarsalis Coquillett, which is the primary mosquito vector of WNV in this region, and prevalence of WNV infection in Cx. tarsalis in the Canadian prairies. The results showed that higher mean temperature and elevated time lagged mean temperature were associated with increased numbers of Cx. tarsalis and higher WNV infection rates. However, increasing precipitation was associated with higher abundance of Cx. tarsalis and lower WNV infection rate. In addition, this study found that increased temperature fluctuation and wetland land cover were associated with decreased infection rate in the Cx. tarsalis population. The resulting monthly models can be used to inform public health interventions by improving the predictions of population abundance of Cx. tarsalis and the transmission intensity of WNV in the Canadian prairies. Furthermore, these models can also be used to examine the potential effects of climate change on the vector population abundance and the distribution of WNV.

  10. Modeling monthly variation of Culex tarsalis (Diptera: Culicidae) abundance and West Nile Virus infection rate in the Canadian Prairies.

    Science.gov (United States)

    Chen, Chen-Chih; Epp, Tasha; Jenkins, Emily; Waldner, Cheryl; Curry, Philip S; Soos, Catherine

    2013-07-22

    The Canadian prairie provinces of Alberta, Saskatchewan, and Manitoba have generally reported the highest human incidence of West Nile virus (WNV) in Canada. In this study, environmental and biotic factors were used to predict numbers of Culex tarsalis Coquillett, which is the primary mosquito vector of WNV in this region, and prevalence of WNV infection in Cx. tarsalis in the Canadian prairies. The results showed that higher mean temperature and elevated time lagged mean temperature were associated with increased numbers of Cx. tarsalis and higher WNV infection rates. However, increasing precipitation was associated with higher abundance of Cx. tarsalis and lower WNV infection rate. In addition, this study found that increased temperature fluctuation and wetland land cover were associated with decreased infection rate in the Cx. tarsalis population. The resulting monthly models can be used to inform public health interventions by improving the predictions of population abundance of Cx. tarsalis and the transmission intensity of WNV in the Canadian prairies. Furthermore, these models can also be used to examine the potential effects of climate change on the vector population abundance and the distribution of WNV.

  11. Biological control of Culex (Culex) saltanensis Dyar, (Diptera, Culicidae) through Bacillus thuringiensis israelensis in laboratory and field conditions

    National Research Council Canada - National Science Library

    João A. C. Zequi; José Lopes

    2007-01-01

    .... thuringiensis israelensis is highly efficient in the control of this mosquito in natural environment with a high level of polluants using the concentration of 2 liters/hectare, with applications every 15 days. Culex (Culex...

  12. Studies of the genus Culex in Florida II. Redescription of the fourth instar of Culex nigripalpus.

    Science.gov (United States)

    Darsie, Richard F; Day, Jonathan F

    2004-06-01

    The fourth instar of Culex nigripalpus is described in detail and completely illustrated for the 1st time as compared with previous descriptions of the larva of Cx. nigripalpus. Certain important features are shown in the figure.

  13. Redescription of the pupa of Culex (Culex) declarator Dyar and Knab (Diptera, Culicidae), with amendments to key to the Culex pupae of the eastern United States.

    Science.gov (United States)

    Darsie, Richard F; Day, Jonathan F

    2005-06-01

    The pupa of Culex declarator was partially described and illustrated by Lane. This species was recently discovered in Florida for the first time and a series of individual rearings have resulted in a number of pupae and an opportunity to redescribe it fully, with a complete illustration. Amendment to the key to the Culex pupae of the eastern United States is provided.

  14. Development of the immature stages of Culex (Culex saltanensis Dyar (Diptera, Culicidae under laboratory conditions

    Directory of Open Access Journals (Sweden)

    João Antonio C. Zequi

    2012-03-01

    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.

  15. Culex mosquitoes are experimentally unable to transmit Zika virus

    Science.gov (United States)

    Amraoui, Fadila; Atyame-Nten, Célestine; Vega-Rúa, Anubis; Lourenço-de-Oliveira, Ricardo; Vazeille, Marie; Failloux, Anna Bella

    2016-01-01

    We report that two laboratory colonies of Culex quinquefasciatus and Culex pipiens mosquitoes were experimentally unable to transmit ZIKV either up to 21 days post an infectious blood meal or up to 14 days post intrathoracic inoculation. Infectious viral particles were detected in bodies, heads or saliva by a plaque forming unit assay on Vero cells. We therefore consider it unlikely that Culex mosquitoes are involved in the rapid spread of ZIKV. PMID:27605159

  16. Redescription of the pupa of Culex restuans and a comparison with Culex nigripalpus.

    Science.gov (United States)

    Darsie, Richard F; Day, Jonathan F

    2007-06-01

    The pupa of Culex restuans is redescribed in detail with a chaetotaxal table and a full illustration. The chaetotaxy of the pupa of Cx. restuans is compared with that of Cx. nigripalpus, the primary vector of St. Louis encephalitis and West Nile virus in Florida.

  17. The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae, in Mexico City

    Directory of Open Access Journals (Sweden)

    Diaz-Perez Alfonso

    2011-05-01

    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

  18. ANCAMAN DARI NYAMUK Culex sp YANG TERABAIKAN

    Directory of Open Access Journals (Sweden)

    Zumrotus Sholichah

    2012-11-01

    Full Text Available Nyamuk Culex sp lebih menyukai meletakkan telurnya pada genangan air berpolutan tinggi, berkembang biak di air keruh dan lebih menyukai genangan air yang sudah lama daripada genangan air yang baru. Aktif menggigit pada malam hari. Tempat yang gelap, sejuk dan lembab merupakan tempat yang disukai untuk beristirahat. Nyamuk betina dewasa menggigit dengan abdomen terletak sejajar dengan permukaan induk semang yang sedang digigit.Gangguan yang ditimbulkan oleh nyamuk selain dapat menularkan penyakit juga dapat sangat mengganggu dengan dengungan dan gigitannya sehingga bagi orang-orang tertentu dapat menimbulkan phobi (entomopobhia serta dapat menyebabkan dermatitis dan urticaria.

  19. Host plant oviposition preference of Bactrocera cucurbitae (Coquillett) (Diptera : Tephritidae)%瓜实蝇对寄主植物的产卵选择性

    Institute of Scientific and Technical Information of China (English)

    彭帅; 郑丽霞; 吴伟坚

    2013-01-01

    The melon fruit fly, Bactrocera cucurbitae ( Coquillett) has been reported to damage more than 100 host plants and is a major pest of cucurbitaceous vegetables. Choice oviposition experiments were conducted under laboratory conditions to help assess host plant specificity of the fruit fly. Six host species: Momordica charantiap, Luffa cylindrical, Cucumis sativus, Cucurbita moschata, Carica papaya and Cucurbita pepo were tested. Oviposition rates were highest on M. charantiap (56. 18% of eggs) and C. sativus (29. 00% ) , with low rates on C. papaya (1. 85% ) and C. moschata (0. 00% ) . In contrast, Oviposition rates were highest on C. sativus ( 34. 64% ) , C. pepo ( 30. 37% ) and C. moschata (18. 05% ) , with low rates on C. papaya (0. 60% ) when the fruit peel were pared. Oviposition rates of B. cucurbitae females on fruits with peel had a significant negative correlation with the hardness of peel, and the correlation coefficient was - 0. 8772. The results imply that in addition to the in - built chemical compounds, plants have physical barrier like hard fruit peel, which impact melon fruit fly oviposition.%瓜实蝇Bactrocera cucurbitae (Coquillett)可危害100多种寄主植物,是葫芦科蔬菜的重要害虫.为了探明瓜实蝇的寄主特异性,在实验室条件下研究了瓜实蝇对黄瓜Cucumis sativus、苦瓜Momordica charantiap、丝瓜Luffa cylindrica、南瓜Cucurbita moschata、番木瓜Carica papaya和西葫芦Cucurbita pepo的产卵选择性.瓜实蝇在苦瓜和黄瓜上的产卵比率较高,分别为56.18%和29.00%,在番木瓜和南瓜上产卵比率较低,分别为1.85%和0.00%,但是在去掉果皮后,黄瓜、西葫芦和南瓜的产卵比率较高,分别达到34.64%、30.37%和18.05%,在番木瓜上的产卵率较低仅为0.60%.瓜实蝇雌虫在带皮果实上的产卵比率与果皮硬度呈显著的负相关关系,相关系数为-0.8772结果表明除了自身的化合物之外,植物具有的物理屏障如坚硬的

  20. Decreased Flight Activity in Culex pipiens (Diptera: Culicidae) Naturally Infected With Culex flavivirus.

    Science.gov (United States)

    Newman, Christina M; Anderson, Tavis K; Goldberg, Tony L

    2016-01-01

    Insect-specific flaviviruses (ISFVs) commonly infect vectors of mosquito-borne arboviruses. To investigate whether infection with an ISFV might affect mosquito flight behavior, we quantified flight behavior in Culex pipiens L. naturally infected with Culex flavivirus (CxFV). We observed a significant reduction in the scotophase (dark hours) flight activity of CxFV-positive mosquitoes relative to CxFV-negative mosquitoes, but only a marginal reduction in photophase (light hours) flight activity, and no change in the circadian pattern of flight activity. These results suggest that CxFV infection alters the flight activity of naturally infected Cx. pipiens most dramatically when these vectors are likely to be host seeking and may therefore affect the transmission of medically important arboviruses.

  1. First report of Culex (Culex) tritaeniorhynchus Giles, 1901 (Diptera: Culicidae) in the Cape Verde Islands

    OpenAIRE

    Alves, Joana; Pina, Adilson de; Diallo, Mawlouth; Dia, Ibrahima

    2015-01-01

    During an entomological survey in Santiago Island, Cape Verde Islands, in November-December 2011 in order to study the bio-ecology and susceptibility to insecticides of Anopheles arabiensis Patton, 1905, Culex tritaeniorhynchus Giles, 1901 was found to be present in the Santa Cruz District. Both adult and immature specimens were collected and a description of both is given. Further confirmation of the taxonomic identity of the specimens was obtained from studying the male genitalia. This is t...

  2. Oviposition responses of gravid Culex quinquefasciatus and Culex tarsalis to bulrush (Schoenoplectus acutus) infusions.

    Science.gov (United States)

    Du, Y; Millar, J G

    1999-12-01

    Laboratory bioassays demonstrated that fermented infusions of dried bulrushes (Schoenoplectus acutus) strongly attracted and stimulated oviposition by gravid female Culex quinquefasciatus and Culex tarsalis. The responses of the 2 species varied with the concentration and method of preparation of the infusions, with responses generally increasing with increasing concentration. No major differences were found in the responses of either species to infusions prepared with bulrushes alone, or with bulrushes plus lactalbumin hydrolysate and brewer's yeast. Infusions remained more attractive than distilled water controls to both species for up to 8 wk. Field tests corroborated the results from the laboratory bioassays. Culex quinquefasciatus, Cx. tarsalis, and Cx. stigmatosoma egg rafts were collected from water pan traps baited with bulrush infusions. A few Culiseta incidens eggs also were collected. In multiple-choice tests using gravid female or egg traps, Cx. quinquefasciatus preferred the most concentrated bulrush infusions, whereas Cx. tarsalis preferred intermediate concentrations. Female Cx. stigmatosoma and Culiseta incidens also were attracted. Overall, these results may provide new leads towards developing synthetic chemical baits to attract bloodfed mosquitoes.

  3. Studies on mid gut microbiota of wild caught Culex (Culex quinquefasciatus mosquitoes from Barasat (North 24 Parganas of West Bengal.

    Directory of Open Access Journals (Sweden)

    Abhishek Pal

    2014-06-01

    Full Text Available Mosquitoes are haematophagous insects that serve as obligate intermediate host for numerous diseases like Filaria, Malaria, Dengue, etc. Mosquitoes can be considered as a holobiont units in which host (mosquitoes and its gut microbiota are involved in a complex reciprocal interaction. The naturally acquired microbiota can modulate mosquitos’ vectorial capacity by inhibiting the development of pathogens. But, enough care has not been taken in West Bengal to investigate on the midgut microbiota of Culex mosquitoes. Therefore, a preliminary attempt has been undertaken to study the morphology, growth pattern and antibiotic susceptibility of midgut microbiota of Culex (Culex quinquefasciatus mosquitoes collected from Barasat areas (North 24 Parganas of West Bengal..

  4. Pond dyes are Culex mosquito oviposition attractants

    Directory of Open Access Journals (Sweden)

    Natali Ortiz Perea

    2017-05-01

    Full Text Available Background British mosquito population distribution, abundance, species composition and potential for mosquito disease transmission are intimately linked to the physical environment. The presence of ponds and water storage can significantly increase the density of particular mosquito species in the garden. Culex pipiens is the mosquito most commonly found in UK gardens and a potential vector of West Nile Virus WNV, although the current risk of transmission is low. However any factors that significantly change the distribution and population of C. pipiens are likely to impact subsequent risk of disease transmission. Pond dyes are used to control algal growth and improve aesthetics of still water reflecting surrounding planting. However, it is well documented that females of some species of mosquito prefer to lay eggs in dark water and/or containers of different colours and we predict that dyed ponds will be attractive to Culex mosquitoes. Methods Black pond dye was used in oviposition choice tests using wild-caught gravid C. pipiens. Larvae from wild-caught C. pipiens were also reared in the pond dye to determine whether it had any impact on survival. An emergence trap caught any adults that emerged from the water. Water butts (80 L were positioned around university glasshouses and woodland and treated with black pond dye or left undyed. Weekly sampling over a six month period through summer and autumn was performed to quantified numbers of larvae and pupae in each treatment and habitat. Results Gravid female Culex mosquitoes preferred to lay eggs in dyed water. This was highly significant in tests conducted under laboratory conditions and in a semi-field choice test. Despite this, survivorship in black dyed water was significantly reduced compared to undyed water. Seasonal analysis of wild larval and pupal numbers in two habitats with and without dye showed no impact of dye but a significant impact of season and habitat. Mosquitoes were more

  5. Common Culex Mosquitoes Don't Transmit Zika Virus

    Science.gov (United States)

    ... 161186.html Common Culex Mosquitoes Don't Transmit Zika Virus: Study These widespread insects do spread West Nile ... t appear to be able to transmit the Zika virus to people, researchers report. The researchers at Kansas ...

  6. Description of immature stages of Culex ocossa Dyar & Knab, Culex delpontei Duret and Culex pereyrai Duret of the Melanoconion subgenus (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Maria Anice Mureb Sallum

    2001-10-01

    Full Text Available The larva and pupa of Culex (Melanoconion ocossa Dyar & Knab are redescribed and those of Culex (Melanoconion delpontei Duret and Culex (Melanoconion pereyrai Duret are described from specimens collected in the states of São Paulo and Paraná, Brazil. The pupa of Cx. ocossa differs from those of the other two species in having seta 5-IV-VI dark with strongly aciculated branches, and caudolateral angle of segment VIII produced into sharp point, and seta 1-P present; Cx. delpontei can be distinguished from Cx. pereyrai in possessing paddle lightly tanned, trumpet flared, and wing and leg cases lightly tanned, without pattern of dark spots; Cx. pereyrai can be recognized by having wing case with pattern of dark, discontinuously pigmented, longitudinal lines, and trumpet cylindrical, not flared. The larvae of the three species share the presence of seta 2-C placed medially to seta 1-C.

  7. Studies on mosquitoes (Diptera: Culicidae and anthropic environment: 10- survey of adult behaviour of Culex nigripalpus and other species of Culex (Culex in South-Eastern Brazil

    Directory of Open Access Journals (Sweden)

    Oswaldo Paulo Forattini

    1995-08-01

    Full Text Available A survey of adult behaviour of Culex (Culex species was carried out from August 1992 through December 1993 in a human modified (anthropic environment in the Ribeira Valley, S.Paulo State, Brazil. Culex nigripalpus dominated the catches at several sites and it's tendency to increase in the anthropic environment became quite clear. Nevertheless no high level of synanthropy was demonstrated. So it seems that the mosquito may have a restricted role in natural arbovirus cycles. Nonetheless, Cx. nigripalpus must be considered a potential vector of arboviruses, especially St. Louis encephalitis virus outside dwellings.São relatados os resultados obtidos mediante coletas regulares de adultos de Culex (Culex em ambientes antrópico do Vale do Ribeira, SP, Brasil, no período de agosto de 1992 a dezembro de 1993. Pôde-se evidenciar a dominancia de Culex nigripalpus nas várias coletas efetuadas. Revelou-se claramente a preferência por parte desse mosquito em aumentar sua densidade no ambiente antrópico. Todavia, sua freqüência ao domicílio mostrou-se baixa, revelando fraco grau de sinantropia. Assim sendo, seu papel vetor de arbovirus parece restringir-se à participação no ciclo natural desses agentes infecciosos. Contudo, pode-se considerá-lo como vetor potencial no meio extradomiciliar. Nesse particular, seu papel pode não ser negligenciável, especialmente no que tange à possibilidade de transmissão de encefalite de S.Luís, cujo agente já foi assinalado na região.

  8. The arbovirus vector Culex torrentium is more prevalent than Culex pipiens in northern and central Europe.

    Science.gov (United States)

    Hesson, J C; Rettich, F; Merdić, E; Vignjević, G; Ostman, O; Schäfer, M; Schaffner, F; Foussadier, R; Besnard, G; Medlock, J; Scholte, E-J; Lundström, J O

    2014-06-01

    Two species of arbovirus vector, Culex torrentium and Culex pipiens (Diptera: Culicidae), occur in several European countries, but difficulties in their accurate identification and discrimination have hampered both detailed and large-scale distribution and abundance studies. Using a molecular identification method, we identified to species 2559 larvae of Cx. pipiens/torrentium collected from 138 sites in 13 European countries ranging from Scandinavia to the Mediterranean coast. In addition, samples of 1712 males of Cx. pipiens/torrentium collected at several sites in the Czech Republic were identified to species based on the morphology of their hypopygia. We found that the two species occur together in large areas of Europe, and that Cx. torrentium dominates in northern Europe and Cx. pipiens dominates south of the Alps. The transition in dominance occurs in central Europe, where both species are roughly equally common. There was a strong correlation between the length of the growing season at different sites and occurrences of the two species. As the growing season increases, the proportion and detection of Cx. torrentium decrease, whereas those of Cx. pipiens increase. The present findings have important consequences for the interpretation of the results of studies on major enzootic and link-vectors of mosquito-borne bird-associated viruses (i.e. Sindbis, West Nile and Usutu viruses), especially in central Europe and Scandinavia.

  9. Mom Matters: Diapause Characteristics of Culex pipiens-Culex quinquefasciatus (Diptera: Culicidae) Hybrid Mosquitoes.

    Science.gov (United States)

    Meuti, Megan E; Short, Clancy A; Denlinger, David L

    2015-03-01

    Females of the northern house mosquito, Culex pipiens L., are capable of entering an adult overwintering diapause characterized by arrested ovarian development, enhanced stress tolerance, and elevated lipid stores. In contrast, the southern house mosquito, Culex quinquefasciatus Say, lacks this capacity and is therefore unable to survive the harsh winters found in northern regions of North America. These two species are capable of forming fertile hybrids in the United States, yet the diapause characteristics of these hybrids have not been extensively investigated. We crossed Cx. pipiens from Columbus, OH, with Cx. quinquefasciatus from Vero Beach, FL, and reared F1 hybrids from all mothers separately under diapause-inducing, short-day conditions (a photoperiod of 8:16 [L:D] h) at 18°C. Egg follicle length and lipid content were used to assess the diapause status of hybrids. Diapause incidence of hybrids varied widely for progeny from different mothers of the same species, but hybrids with Cx. pipiens mothers were consistently more prone to enter diapause than hybrids that had Cx. quinquefasciatus mothers. Our results suggest a strong maternal influence on the diapause phenotype and that a high percentage (45-75%) of Cx. pipiens-Cx. quinquefasciatus hybrids are capable of entering diapause. This implies that many hybrids can successfully overwinter, leading to a possible widening of the hybrid zone of these two species in North America.

  10. The contrasting bionomics of Culex mosquitoes in western North America.

    Science.gov (United States)

    Reisen, William K

    2012-12-01

    Mosquitoes in the genus Culex are the primary enzootic maintenance and bridge vectors of the North American encephalitides, now including West Nile virus. This review briefly summarizes the biology of three key vector species in western North America, Culex tarsalis, Cx. pipiens complex and Cx. stigmatosoma, focusing on the long history of research done in California. Topics reviewed include population genetic structure, larval ecology, autogeny, mating behavior, host-seeking behavior, host-selection patterns, and overwintering strategies. These attributes collectively have allowed the successful exploitation of anthropogenically altered ecosystems and enabled the role of these species as maintenance and bridge vectors of arboviruses.

  11. Larvicidal, repellent, and ovicidal activity of marine actinobacteria extracts against Culex tritaeniorhynchus and Culex gelidus.

    Science.gov (United States)

    Karthik, L; Gaurav, K; Rao, K V Bhaskara; Rajakumar, G; Rahuman, A Abdul

    2011-06-01

    The purpose of the present study was to assess the effect of crude extracts of marine actinobacteria on larvicidal, repellent, and ovicidal activities against Culex tritaeniorhynchus and Culex gelidus (Diptera: Culicidae). The early fourth instar larvae of C. tritaeniorhynchus and C. gelidus, reared in the laboratory, were used for larvicidal, ovicidal, and repellent assay with crude extracts of actinobacteria. Saccharomonospora spp. (LK-1), Streptomyces roseiscleroticus (LK-2), and Streptomyces gedanensis (LK-3) were identified as potential biocide producers. Based on the antimicrobial activity, three strains were chosen for larvicidal activity. The marine actinobacterial extracts showed moderate to high larvicidal effects after 24 h of exposure at 1,000 ppm and the highest larval mortality was found in extract of LK-3 (LC(50) = 108.08 ppm and LC(90) = 609.15 ppm) against the larvae of C. gelidus and (LC(50) = 146.24 ppm and LC(90) = 762.69 ppm) against the larvae of C. tritaeniorhynchus. Complete protections for 240 min were found in crude extract of LK-2 and LK-3 at 1,000 ppm, against mosquito bites of C. tritaeniorhynchus and C. gelidus, respectively. After 24-h treatment, mean percent hatchability of the ovicidal activity was observed. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. Crude extracts of LK-1 and LK-3 showed no hatchability at 1,000 ppm against C. tritaeniorhynchus and C. gelidus, respectively. This is an ideal ecofriendly approach for the control of Japanese encephalitis vectors, C. tritaeniorhynchus and C. gelidus.

  12. Transmission of West Nile virus by Culex quinquefasciatus say infected with Culex Flavivirus Izabal.

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    Rebekah J Kent

    Full Text Available BACKGROUND: The natural history and potential impact of mosquito-specific flaviviruses on the transmission efficiency of West Nile virus (WNV is unknown. The objective of this study was to determine whether or not prior infection with Culex flavivirus (CxFV Izabal altered the vector competence of Cx. quinquefasciatus Say for transmission of a co-circulating strain of West Nile virus (WNV from Guatemala. METHODS AND FINDINGS: CxFV-negative Culex quinquefasciatus and those infected with CxFV Izabal by intrathoracic inoculation were administered WNV-infectious blood meals. Infection, dissemination, and transmission of WNV were measured by plaque titration on Vero cells of individual mosquito bodies, legs, or saliva, respectively, two weeks following WNV exposure. Additional groups of Cx. quinquefasciatus were intrathoracically inoculated with WNV alone or WNV+CxFV Izabal simultaneously, and saliva collected nine days post inoculation. Growth of WNV in Aedes albopictus C6/36 cells or Cx. quinquefasciatus was not inhibited by prior infection with CxFV Izabal. There was no significant difference in the vector competence of Cx. quinquefasciatus for WNV between mosquitoes uninfected or infected with CxFV Izabal across multiple WNV blood meal titers and two colonies of Cx. quinquefasciatus (p>0.05. However, significantly more Cx. quinquefasciatus from Honduras that were co-inoculated simultaneously with both viruses transmitted WNV than those inoculated with WNV alone (p = 0.0014. Co-inoculated mosquitoes that transmitted WNV also contained CxFV in their saliva, whereas mosquitoes inoculated with CxFV alone did not contain virus in their saliva. CONCLUSIONS: In the sequential infection experiments, prior infection with CxFV Izabal had no significant impact on WNV replication, infection, dissemination, or transmission by Cx. quinquefasciatus, however WNV transmission was enhanced in the Honduras colony when mosquitoes were inoculated simultaneously with

  13. Vector competence of Anopheles and Culex mosquitoes for Zika virus

    Directory of Open Access Journals (Sweden)

    Brittany L. Dodson

    2017-03-01

    Full Text Available Zika virus is a newly emergent mosquito-borne flavivirus that has caused recent large outbreaks in the new world, leading to dramatic increases in serious disease pathology including Guillain-Barre syndrome, newborn microcephaly, and infant brain damage. Although Aedes mosquitoes are thought to be the primary mosquito species driving infection, the virus has been isolated from dozens of mosquito species, including Culex and Anopheles species, and we lack a thorough understanding of which mosquito species to target for vector control. We exposed Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes to blood meals supplemented with two Zika virus strains. Mosquito bodies, legs, and saliva were collected five, seven, and 14 days post blood meal and tested for infectious virus by plaque assay. Regardless of titer, virus strain, or timepoint, Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes were refractory to Zika virus infection. We conclude that Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes likely do not contribute significantly to Zika virus transmission to humans. However, future studies should continue to explore the potential for other novel potential vectors to transmit the virus.

  14. Vector competence of Anopheles and Culex mosquitoes for Zika virus

    Science.gov (United States)

    Dodson, Brittany L.

    2017-01-01

    Zika virus is a newly emergent mosquito-borne flavivirus that has caused recent large outbreaks in the new world, leading to dramatic increases in serious disease pathology including Guillain-Barre syndrome, newborn microcephaly, and infant brain damage. Although Aedes mosquitoes are thought to be the primary mosquito species driving infection, the virus has been isolated from dozens of mosquito species, including Culex and Anopheles species, and we lack a thorough understanding of which mosquito species to target for vector control. We exposed Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes to blood meals supplemented with two Zika virus strains. Mosquito bodies, legs, and saliva were collected five, seven, and 14 days post blood meal and tested for infectious virus by plaque assay. Regardless of titer, virus strain, or timepoint, Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes were refractory to Zika virus infection. We conclude that Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes likely do not contribute significantly to Zika virus transmission to humans. However, future studies should continue to explore the potential for other novel potential vectors to transmit the virus. PMID:28316896

  15. Repellent activity of five essential oils against Culex pipiens.

    Science.gov (United States)

    Erler, F; Ulug, I; Yalcinkaya, B

    2006-12-01

    Essential oils extracted from the seeds of anise (Pimpinella anisum), dried fruits of eucalyptus (Eucalyptus camaldulensis), dried foliage of mint (Mentha piperita) and basil (Ocimum basilicum) and fresh foliage of laurel (Laurus nobilis) were tested for their repellency against the adult females of Culex pipiens. All essential oils showed repellency in varying degrees, eucalyptus, basil and anise being the most active.

  16. Discovery of Culex (Neoculex) arizonensis in Texas (Diptera, Culicidae).

    Science.gov (United States)

    Reeves, Will K; Darsie, Richard F

    2003-03-01

    A population of Culex arizonensis was found in Guadalupe Mountains National Park, Culberson County, TX. A new state record, this extends the range of this species eastward by 828 km. The essential diagnostic characters of the 4th-stage larva are given.

  17. Vector competence of Anopheles and Culex mosquitoes for Zika virus.

    Science.gov (United States)

    Dodson, Brittany L; Rasgon, Jason L

    2017-01-01

    Zika virus is a newly emergent mosquito-borne flavivirus that has caused recent large outbreaks in the new world, leading to dramatic increases in serious disease pathology including Guillain-Barre syndrome, newborn microcephaly, and infant brain damage. Although Aedes mosquitoes are thought to be the primary mosquito species driving infection, the virus has been isolated from dozens of mosquito species, including Culex and Anopheles species, and we lack a thorough understanding of which mosquito species to target for vector control. We exposed Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes to blood meals supplemented with two Zika virus strains. Mosquito bodies, legs, and saliva were collected five, seven, and 14 days post blood meal and tested for infectious virus by plaque assay. Regardless of titer, virus strain, or timepoint, Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes were refractory to Zika virus infection. We conclude that Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes likely do not contribute significantly to Zika virus transmission to humans. However, future studies should continue to explore the potential for other novel potential vectors to transmit the virus.

  18. Oviposition Preferences for Infusion-Baited Traps and Seasonal Abundance of Culex Mosquitoes in Southwestern Virginia

    OpenAIRE

    Jackson, Bryan Tyler

    2004-01-01

    Field studies were conducted in southwestern Virginia to determine the bionomics and ovipositional preferences of Culex restuans Theobald and Culex pipiens Linnaeus using ovitraps and gravid traps. Both species have been implicated as enzootic and epizootic vectors of West Nile virus (WNV) and these studies provide information on the relative abundance of gravid mosquitoes. Ovitraps were used in the summers of 2002 and 2003 to measure the oviposition activity of Culex mosquitoes, main...

  19. Vector competence of Kenyan Culex zombaensis and Culex quinquefasciatus mosquitoes for Rift Valley fever virus.

    Science.gov (United States)

    Turell, M J; Lee, J S; Richardson, J H; Sang, R C; Kioko, E N; Agawo, M O; Pecor, J; O'Guinn, M L

    2007-12-01

    Rift Valley fever (RVF) continues to be a significant problem in Kenya as well as in Egypt, Yemen, and Saudi Arabia. In order to determine the ability of Kenyan mosquitoes to transmit RVF virus (RVFV), we collected mosquitoes in the Lake Naivasha region of Kenya and evaluated them for their potential to transmit RVFV under laboratory conditions. After feeding on a hamster (Mesocricetus auratus) with a viremia of 10(9.7) plaque-forming units of virus/ml of blood, Culex zombaensis were highly susceptible to infection with RVFV, with 89% becoming infected. In contrast, Cx. quinquefasciatus that were fed on the same hamsters were marginally susceptible, with only 20% becoming infected. Differences in percentages of mosquitoes that developed a disseminated infection were equally disparate, with 55% and 8%, for Cx. zombaensis and Cx. quinquefasciatus, respectively. Forty-eight percent of the Cx. zombaensis with a disseminated infection that fed on a susceptible hamster transmitted virus by bite, indicating a moderate salivary gland barrier. However, the presence of a salivary gland barrier could not be determined for Cx. quinquefasciatus because none of the 18 mosquitoes that took a 2nd blood meal had a disseminated infection. These studies illustrate the need to identify the ability of individual mosquito species to transmit RVFV so that correct decisions can be made concerning the application of appropriate control measures during an outbreak.

  20. Culex pipiens and Culex restuans mosquitoes harbor distinct microbiota dominated by few bacterial taxa.

    Science.gov (United States)

    Muturi, Ephantus J; Kim, Chang-Hyun; Bara, Jeffrey; Bach, Elizabeth M; Siddappaji, Madhura H

    2016-01-13

    Mosquitoes host diverse microbial communities that influence many aspects of their biology including reproduction, digestion, and ability to transmit pathogens. Unraveling the composition, structure, and function of these microbiota can provide new opportunities for exploiting microbial function for mosquito-borne disease control. MiSeq® sequencing of 16S rRNA gene amplicons was used to characterize the microbiota of adult females of Culex pipiens L. and Cx. restuans Theobald collected from nine study sites in central Illinois. Out of 195 bacterial OTUs that were identified, 86 were shared between the two mosquito species while 16 and 93 OTUs were unique to Cx. pipiens and Cx. restuans, respectively. The composition and structure of microbial communities differed significantly between the two mosquito species with Cx. restuans hosting a more diverse bacterial community compared to Cx. pipiens. Wolbachia (OTU836919) was the dominant bacterial species in Cx. pipiens accounting for 91% of total microbiota while Sphingomonas (OTU817982) was the dominant bacterial species in Cx. restuans accounting for 31% of total microbiota. Only 3 and 6 OTUs occurred in over 60% of individuals in Cx. pipiens and Cx. restuans, respectively. There was little effect of study site on bacterial community structure of either mosquito species. These results suggest that the two mosquito species support distinct microbial communities that are sparsely distributed between individuals. These findings will allow investigations of the role of identified microbiota on the spatial and temporal heterogeneity in WNV transmission and their potential application in disease control.

  1. Lead levels of Culex mosquito larvae inhabiting lead utilizing factory

    Institute of Scientific and Technical Information of China (English)

    Kitvatanachai S; Apiwathnasorn C; Leemingsawat S; Wongwit W; Overgaard HJ

    2011-01-01

    Objective: To determine lead level primarily in Culex quinquefasciatus (Cx. quinquefasciatus), and Culex gelidus (Cx. gelidus) larvae inhabiting lead consuming factories, and to putatively estimate eco-toxicological impact of effluents from the firms. Methods: Third instars larvae were sampled by standard dipping method and lead concentrations in the larvae and their respective surrounding factory aquatic environments were determined through standard atomic absorption spectrophotometry (AAS). Results: Cx. quinquefasciatus was the most abundant species followed by Cx. gelidus. The levels of lead were higher in the Cx. quinquefasciatus (1.08-47.47 μg/g), than in the wastewaters surface (0.01-0.78 μg/mL) from the factories or closer areas around factories. Other species were not reaching the criteria for lead determination. Conclusions: The Cx.quinquefasciatus larvae can bio-accumulate the metal and can potentially serve as a biomarker of lead contamination, to complemente conventional techniques.

  2. Culex coronator Dyar and Knab: a new Florida species record.

    Science.gov (United States)

    Smith, John P; Walsh, Jimmy D; Cope, Eric H; Tennant, Richard A; Kozak, John A; Darsie, Richard F

    2006-06-01

    We report the first finding of Culex coronator Dyar and Knab in Florida, based on multiple adult collections from several locations in the western panhandle of Florida. GPS coordinates and habitat descriptions are given and disease implications are discussed. These records extend the known distribution of Cx. coronator from six other states (Arizona, Louisiana, Mississippi, New Mexico, Oklahoma, and Texas), and from Mexico to Argentina.

  3. Culex pipiens quinquefasciatus: a potential vector to transmit Zika virus.

    Science.gov (United States)

    Guo, Xiao-Xia; Li, Chun-Xiao; Deng, Yong-Qiang; Xing, Dan; Liu, Qin-Mei; Wu, Qun; Sun, Ai-Juan; Dong, Yan-de; Cao, Wu-Chun; Qin, Cheng-Feng; Zhao, Tong-Yan

    2016-09-07

    Zika virus (ZIKV) has become a threat to global health since the outbreak in Brazil in 2015. Although ZIKV is generally considered an Aedes-transmitted pathogen, new evidence has shown that parts of the virus closely resemble Culex-transmitted viruses. Therefore, it is important to evaluate the competence of Culex species for ZIKV to understand their potential as vectors. In this study, female Culex pipiens quinquefasciatus were orally exposed to ZIKV. Mosquito midguts, salivary glands and ovaries were tested for ZIKV to measure infection and dissemination at 2, 4, 6, 8, 12, 16 and 18 days post exposure (pe). In addition, saliva was collected from mosquitoes after infection and infant mice were bitten by infected mosquitoes to measure the transmission ability of Cx. p. quinquefasciatus. The results showed that the peak time of virus appearance in the salivary glands was day 8 pe, with 90% infection rate and an estimated virus titer of 3.92±0.49 lg RNA copies/mL. Eight of the nine infant mice had positive brains after being bitten by infected mosquitoes, which meant that Cx. p. quinquefasciatus could be infected with and transmit ZIKV following oral infection. These laboratory results clearly demonstrate the potential role of Cx. p. quinquefasciatus as a vector of ZIKV in China. Because there are quite different vector management strategies required to control Aedes (Stegomyia) species and Cx. p. quinquefasciatus, an integrated approach may be required should a Zika epidemic occur.

  4. Observações sobre os mosquitos Culex da cidade de São Paulo, Brasil Observations on Culex mosquitoes of S. Paulo City, Brazil

    Directory of Open Access Journals (Sweden)

    Oswaldo Paulo Forattini

    1973-12-01

    Full Text Available São apresentados os resultados obtidos na coleta de mosquitos do gênero Culex na área urbana da cidade de São Paulo, Brasil. Foram empregadas armadilhas luminosas automáticas tipo "New Jersey 50". Os resultados revelaram a presença de outras populações representadas principalmente por Culex chidesteri, C. dolosus e C. bidens as quais, em conjunto, chegaram algumas vezes a sobrepujar a de Culex pipiens fatigans. O maior rendimento foi obtido em áreas com abastecimento de água mas sem rede de esgotos. As coletas intradomiciliares revelaram franca predominância de C. pipiens fatigans.With the use of New Jersey-50 light traps, a survey of Culex mosquitoes was made in the urban área of São Paulo City, Brazil. Beside Culex pipiens fatigans several other species were found, mainly represented by Culex chidesteri, C. dolosus and C. bidens. The combined incidence of these three populations follows nearly the fatigans one and frequently exceeding it. The most high levels of density were found at areas with water treatment but without sewage disposal. Domiciliary collections showed great Culex pipiens fatigans predominancy.

  5. Molecular identification of two Culex (Culex) species of the neotropical region (Diptera: Culicidae)

    Science.gov (United States)

    Almirón, Walter R.; Gardenal, Cristina N.

    2017-01-01

    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. PMID:28235083

  6. Variation in Mitochondrial Cytochrome c Oxidase I DNA Can Successfully Identify Culex (Melanoconion) pedroi (Diptera: Culicidae) and Culex (Melanoconion) ribeirensis (Diptera: Culicidae).

    Science.gov (United States)

    Araki, A S; Maia, D A; Gil-Santana, H R; de Mello, C F; Martins, A de J; Alencar, J

    2016-12-22

    Culex (Melanoconion) pedroi Sirivanakarn & Belkin 1980 and Culex (Melanoconion) ribeirensis Forattini & Sallum 1985 are two morphologically very similar species of the Pedroi subgroup of mosquitoes in the Spissipes section of the subgenus Melanoconion of the genus Culex L. 1758. We carried out an analysis of the mitochondrial cytochrome c oxidase I (COI) DNA variation between these two species. The recent observation of sympatric coexistence in a forested area of Rio de Janeiro State (Brazil) triggered the need to validate these two species previously identified based on morphology. We concluded that the COI is a useful tool for identification of Cx. pedroi and Cx. ribeirensis.

  7. Age-stage, two-sex life tables of Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae) with a discussion on the problem of applying female age-specific life tables to insect populations

    Institute of Scientific and Technical Information of China (English)

    Yu-Bing Huang; Hsin Chi

    2012-01-01

    Age-stage,two-sex life tables of the melon fly,Bactrocera cucurbitae ( Coquillett) (Diptera:Tephritidae),reared on cucumber (Cucumis sativus L.),sponge gourd (Luffa cylindrica Roem) and a carrot medium (mashed Daucus carota L.mixed with sucrose and yeast hydrolysate) were constructed under laboratory conditions at 25 ± 1 ℃,65% ± 0.5%relative humidity,and a photoperiod 12 ∶ 12h (L ∶ D).The intrinsic rates of increase of B.cucurbitae were 0.144 6,0.141 2 and 0.068 8 days on cucumber,sponge gourd,and carrot medium,respectively.The highest net reproduction rate was 172 offspring per fly reared on sponge gourd.The mean generation times of B.cucurbitae ranged from 34 days reared on cucumber to 56 days reared on carrot medium.The life history raw data was analyzed using the traditional female age-specific life table and compared to results obtained using the age-stage,two-sex life table.When the age-specific female life table is applied to an age-stage-structured two-sex population,survival and fecundity curves will be improperly manipulated due to an inability to include variation in preadult development time.We discussed different interpretations of the relationship between the net reproductive rate and the intrinsic rate of increase to clarify possible misunderstanding in the literature.

  8. Distribuição sazonal de Culex (Culex eduardoi Casal & Garcia (Diptera, Culicidae em criadouros antrópicos introduzidos em mata residual degradada, área urbana de Curitiba, Paraná,Brasil Seazonal distribution of Culex (Culex eduardoi Casal & Garcia (Diptera, Culicidae in artificial receptacles in disturbed patch of forest degraded inurban area of Curitiba, Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Magda Clara Vieira da Costa Ribeiro

    2002-07-01

    Full Text Available The utilization of artificial receptacles to oviposition by mosquitoes in forest environment may indicate a sinantropic tendency or behaviour. Our data revealed that tires were as the most acceptable breeding for Culex (Culex eduardoi Casal & Garcia 1968.The population density of this species was higher and summer seasons.

  9. The Female Cibarial Armature of New World Culex, Subgenus Melanoconion and Related Subgenera with Notes on this Character in Subgenera Culex, Lutzia and Neoculex and Genera Galindomyia and Deinocerites (Diptera: Culicidae)

    Science.gov (United States)

    1978-01-01

    Subgenus Mieraedes: antiZ&mmagnorum Dyar ( Puerto Rico), bisuzcatus (Coquillett) (Dominican Republic). Subgenus MicrocuZex: eonsozator Dyar and...in the spissipes subtype (spissipes, eprmastasis, opisthopus, por- tesi , taeniopus and vomerifer) based on the cibarial armature as shown here and

  10. Original article. Biting behavior of Malaysian mosquitoes, Aedes albopictus Skuse, Armigeres kesseli Ramalingam, Culex quinquefasciatus Say, and Culex vishnui Theobald obtained from urban residential areas in Kuala Lumpur

    National Research Council Canada - National Science Library

    Chee Dhang Chen; Han Lim Lee; Koon Weng Lau; Abdul Ghani Abdullah; Swee Beng Tan; Ibrahim Sa’diyah; Yusoff Norma-Rashid; Pei Fen Oh; Chi Kian Chan; Mohd Sofian-Azirun

    2014-01-01

    .... The mosquitoes of major concern in Malaysia belong to the genera Culex, Aedes, and Armigeres. Objective: To study the host-seeking behavior of four Malaysian mosquitoes commonly found in urban residential areas in Kuala Lumpur...

  11. Isolation and Biochemical Characterizations of Mid Gut Microbiota of Culex (Culex quinquefasciatus Mosquitoes in Some Urban Sub Urban & Rural Areas of West Bengal.

    Directory of Open Access Journals (Sweden)

    Rahul Kumar

    2013-06-01

    Full Text Available Mosquitoes, in general are medically important vectors of many diseases like Malaria, Dengue and Filariasis, which are a great challenge for public health in many countries. All animals and plants establish symbiotic relationship with microbes. Mosquitoes can be considered as an holobiont units in which the host (mosquito and its microbiota are involved in complex reciprocal multipartite interaction such as host reproduction and survival, protection against natural enemies. This naturally acquired microbial flora can modulate the mosquitos’ vectorial capacity by inhibiting the development of pathogen. But enough care has not been under taken regarding the biochemical characterization of Culex mosquitoes (Culex quinquefasciatus in West Bengal. Therefore a preliminary investigation have been undertaken for the determination of biochemical characterization such as gram staining, pattern of growth, detection of economically important enzyme as well as antibiotic susceptibility assay of midgut bacterial isolates of Culex (Culex quinquefasciatus in some urban, sub-urban and rural areas of West Bengal.

  12. Catepsinas B vitelolíticas de Culex quinquefasciatus.

    OpenAIRE

    Alexandre Santos de Moura

    2014-01-01

    Apesar de Culex quinquefasciatus ser um eficiente vetor de doenças tais como a filariose linfática, febre do Nilo Ocidental e outras várias neuroviroses, poucas pesquisas sobre sua fisiologia têm sido conduzidas. Como em todos os animais ovíparos, o desenvolvimento embrionário dos mosquitos depende da degradação dos nutrientes armazenados no ovo, sendo a catepsina B uma protease que tem sido identificada e caracterizada em vários insetos como envolvida nesta função. Neste trabalho identificam...

  13. Culex mosquitoes in temporary urban rain pools: seasonal dynamics and relation to environmental variables.

    Science.gov (United States)

    Fischer, Sylvia; Schweigmann, Nicolás

    2004-12-01

    The study was conducted in a park of Buenos Aires City, where a total of 89 rain pools were sampled weekly for mosquito immature stages over a one-year period. The aim of the present paper was to investigate the seasonal dynamics of three Culex species breeding in temporary rain pools and to analyze the relationships of the presence of these species to pool dimensions, pool age, vegetation, and insolation degree. The three species showed differences in their seasonal patterns, Culex dolosus being present during the whole year, Culex pipiens mainly in the summer season, and Culex maxi almost exclusively during the fall. The variable explaining most of the variation among sampling dates in species composition was weekly mean temperature. A significant positive association was detected among mosquito species, as they were recorded together more frequently than expected by chance. The statistical analyses performed revealed significant positive relationships of all three mosquito species to increasing surface area, whereas no relationship to insolation degree was detected in the studied pools. Culex pipiens and Culex dolosus showed positive relationships to increasing vegetation cover, whereas the presence of Culex dolosus was also related to pool age.

  14. Lectin Activity in Gut Extract of Culex pipiens.

    Directory of Open Access Journals (Sweden)

    Mona Koosha

    2013-06-01

    Full Text Available The role of lectins is important in interaction between pathogens and mosquito vectors. This study was performed to identify agglutinin activities of protein molecules on the midgut of Culex pipiens.Culex pipiens was reared in insectray condition and the midguts of males and females (blood fed and unfed were dissected separately in Tris-HCl buffer. The extracts of midguts were applied for hemagglutinin assay against red blood cells of rabbit, mouse, rat, dog, horse, sheep, guinea pig, cow, human (A, B, AB, O groups. Then, the RBCs with relatively high agglutinin activity were chosen for carbohydrate inhibition assay. D (+ glucose, D (+ galactose, D (+ mannose, D (- fructose, D (- arabinose, L (- fucose, lactose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, sialic acid were used to specify carbohydrate binding lectin.The highest agglutinin activities were found against sheep and rabbits RBCs. Sexual diversity of agglutinin activities was observed among midgut extraction of males and females. In addition, variation in agglutinin activity of blood fed and unfed female mosquitoes were detected. The lectin activity was inhibited highly with glucose, galactose, fucose and fructose but less inhibitor activities was observed by arabinose, N-acetyl-D-galactosamine, n-acetyl-d-glucosamine, lactose and mannose.The secretion of hemagglutinins (lectins or lectin-like molecules in the digestive system depends on the type of food in the gut. This suggests that emptying of the gut in preparation for protein rich food probably starts the secretion of hemagglutinins.

  15. Synergism between permethrin and propoxur against Culex quinquefasciatus mosquito larvae.

    Science.gov (United States)

    Corbel, V; Chandre, F; Darriet, F; Lardeux, F; Hougard, J-M

    2003-06-01

    To see if synergism occurs between carbamate and pyrethroid insecticides, we tested permethrin and propoxur as representatives of these two classes of compounds used for mosquito control. Larvicidal activity of both insecticides was assessed separately and together on a susceptible strain of the mosquito Culex quinquefasciatus (Diptera: Culicidae) by two methods. When mixed at a constant ratio (permethrin : propoxur 1 : 60 based on LC50) and tested at serial concentrations to plot dose/mortality regression, significant synergy occurred between them (co-toxicity coefficient = 2.2), not just an additive effect. For example, when the mixture gave 50% mortality, the same concentrations of permethrin and propoxur alone would have given merely 2 x 1% mortality. When a sublethal dose (LC0) of permethrin or propoxur was added to the other (range LC10-LC95), synergism occurred up to the LC80 level. Synergistic effects were attributed to the complementary modes of action by these two insecticide classes acting on different components of nerve impulse transmission. Apart from raising new possibilities for Culex control, it seems appropriate to consider using such mixtures or combinations for insecticide-treated mosquito nets in situations with insecticide-resistant Anopheles malaria vectors.

  16. RNA splicing in a new rhabdovirus from Culex mosquitoes.

    Science.gov (United States)

    Kuwata, Ryusei; Isawa, Haruhiko; Hoshino, Keita; Tsuda, Yoshio; Yanase, Tohru; Sasaki, Toshinori; Kobayashi, Mutsuo; Sawabe, Kyoko

    2011-07-01

    Among members of the order Mononegavirales, RNA splicing events have been found only in the family Bornaviridae. Here, we report that a new rhabdovirus isolated from the mosquito Culex tritaeniorhynchus replicates in the nuclei of infected cells and requires RNA splicing for viral mRNA maturation. The virus, designated Culex tritaeniorhynchus rhabdovirus (CTRV), shares a similar genome organization with other rhabdoviruses, except for the presence of a putative intron in the coding region for the L protein. Molecular phylogenetic studies indicated that CTRV belongs to the family Rhabdoviridae, but it is yet to be assigned a genus. Electron microscopic analysis revealed that the CTRV virion is extremely elongated, unlike virions of rhabdoviruses, which are generally bullet shaped. Northern hybridization confirmed that a large transcript (approximately 6,500 nucleotides [nt]) from the CTRV L gene was present in the infected cells. Strand-specific reverse transcription-PCR (RT-PCR) analyses identified the intron-exon boundaries and the 76-nt intron sequence, which contains the typical motif for eukaryotic spliceosomal intron-splice donor/acceptor sites (GU-AG), a predicted branch point, and a polypyrimidine tract. In situ hybridization exhibited that viral RNAs are primarily localized in the nucleus of infected cells, indicating that CTRV replicates in the nucleus and is allowed to utilize the host's nuclear splicing machinery. This is the first report of RNA splicing among the members of the family Rhabdoviridae.

  17. Lectin Activity in Gut Extract of Culex pipiens

    Science.gov (United States)

    Koosha, Mona; Abai, Mohammad Reza; Abolhasani, Mandan; Charedar, Soroor; Basseri, Hamid Reza

    2013-01-01

    Background: The role of lectins is important in interaction between pathogens and mosquito vectors. This study was performed to identify agglutinin activities of protein molecules on the midgut of Culex pipiens. Methods: Culex pipiens was reared in insectray condition and the midguts of males and females (blood fed and unfed) were dissected separately in Tris-HCl buffer. The extracts of midguts were applied for hemagglutinin assay against red blood cells of rabbit, mouse, rat, dog, horse, sheep, guinea pig, cow, human (A, B, AB, O groups). Then, the RBCs with relatively high agglutinin activity were chosen for carbohydrate inhibition assay. D (+) glucose, D (+) galactose, D (+) mannose, D (−) fructose, D (−) arabinose, L (−) fucose, lactose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, sialic acid were used to specify carbohydrate binding lectin. Results: The highest agglutinin activities were found against sheep and rabbits RBCs. Sexual diversity of agglutinin activities was observed among midgut extraction of males and females. In addition, variation in agglutinin activity of blood fed and unfed female mosquitoes were detected. The lectin activity was inhibited highly with glucose, galactose, fucose and fructose but less inhibitor activities was observed by arabinose, N-acetyl-D-galactosamine, n-acetyl-d-glucosamine, lactose and mannose. Conclusion: The secretion of hemagglutinins (lectins or lectin-like molecules) in the digestive system depends on the type of food in the gut. This suggests that emptying of the gut in preparation for protein rich food probably starts the secretion of hemagglutinins. PMID:23785692

  18. Lead levels of Culex mosquito larvae inhabiting lead utilizing factory

    Institute of Scientific and Technical Information of China (English)

    Kitvatanachai; S; Apiwathnasorn; C; Leemingsawat; S; Wongwit; W; Overgaard; HJ

    2011-01-01

    Objective:To determine lead level primarily in Culex quinquefasciatus(Cx.quinquefasciatus), and Culex gelidus(Cx.gelidus) larvae inhabiting lead consuming factories,and to putatively estimate eco-toxicological impact of effluents from the firms.Methods:Third instars larvae were sampled by standard dipping method and lead concentrations in the larvae and their respective surrounding factory aquatic environments were determined through standard atomic absorption spectrophotometry(AAS).Results:Cx.quinquefasciatus was the most abundant species followed by Cx.gelidus.The levels of lead were higher in the Cx.quinquefasciatus(1.08-47.47μg/g),than in the wastewaters surface(0.01-0.78 μg/mL) from the factories or closer areas around factories. Other species were not reaching the.criteria for lead determination.Conclusions:The Cx. quinquefasciatus larvae can bio-accumulate the metal and can potentially serve as a biomarker of lead contamination,to complemente conventional techniques.

  19. West Nile virus vector Culex modestus established in southern England

    Directory of Open Access Journals (Sweden)

    Golding Nick

    2012-02-01

    Full Text Available Abstract Background The risk posed to the United Kingdom by West Nile virus (WNV has previously been considered low, due to the absence or scarcity of the main Culex sp. bridge vectors. The mosquito Culex modestus is widespread in southern Europe, where it acts as the principle bridge vector of WNV. This species was not previously thought to be present in the United Kingdom. Findings Mosquito larval surveys carried out in 2010 identified substantial populations of Cx. modestus at two sites in marshland in southeast England. Host-seeking-adult traps placed at a third site indicate that the relative seasonal abundance of Cx. modestus peaks in early August. DNA barcoding of these specimens from the United Kingdom and material from southern France confirmed the morphological identification. Conclusions Cx. modestus appears to be established in the North Kent Marshes, possibly as the result of a recent introduction. The addition of this species to the United Kingdom's mosquito fauna may increase the risk posed to the United Kingdom by WNV.

  20. Toxicity Determination of Several Insecticides and Their Mixtures to Bactrocera (Zeugodacus) cucurbitae ( Coquillett)%几种杀虫剂及其混配对瓜实蝇成虫的毒力测定

    Institute of Scientific and Technical Information of China (English)

    刘奎; 付步礼; 邱海燕; 符悦冠

    2011-01-01

    采用微量点滴法,测定了毒死蜱、甲维盐、敌敌畏、顺式氯氰菊酯等4种杀虫剂对瓜实蝇成虫的毒力和二元混配的联合毒力.结果表明:80%敌敌畏乳油(EC)的LD50最小,为1.683 9μg·g-1;100g·L-1顺式氯氰菊酯EC的LD50最大,为8.877 0μ g·g-1.供试杀虫剂毒性大小依次为:80%敌敌畏EC>5%甲维盐微乳剂(ME) >480g·L-1毒死蜱EC> 100 g·L-1顺式氯氰菊酯EC.敌敌畏与甲维盐(1∶1)混配的增效作用最强,共毒系数为426.%Four insecticides toxicities to adult of Bactrocera (Zeugodacus ) cucurbitae ( Coquillett) and their co-efficient ratio were determined by micro drop method. The results showed that LD50 of 80 % dichlorvos EC was minimum for 1.683 9 μg ? G-1 and alpha-cypermethrin EC was the largest for 8.877 0 μg ? G-1. The toxicity order was 80 % dichlorvos EC>5 % emamectin-benzoate ME > 480 g ? L-1 chlorpyrifos EC> 100 g ? L-1 alpha-cypermethrin EC. The co-efficient ratio of the mixture of dichlorvos and emamectin-benzoate (1:1) was 426.

  1. The impact of weather conditions on Culex pipiens and Culex restuans (Diptera: Culicidae) abundance: a case study in Peel Region.

    Science.gov (United States)

    Wang, Jiafeng; Ogden, Nick H; Zhu, Huaiping

    2011-03-01

    Mosquito populations are sensitive to long-term variations in climate and short-term variations in weather. Mosquito abundance is a key determinant of outbreaks of mosquito-borne diseases, such as West Nile virus (WNV). In this work, the short-term impact of weather conditions (temperature and precipitation) on Culex pipiens L.-Culex restuans Theobald mosquito abundance in Peel Region, Ontario, Canada, was investigated using the 2002-2009 mosquito data collected from the WNV surveillance program managed by Ontario Ministry of Health and Long-Term Care and a gamma-generalized linear model. There was a clear association between weather conditions (temperature and precipitation) and mosquito abundance, which allowed the definition of threshold criteria for temperature and precipitation conditions for mosquito population growth. A predictive statistical model for mosquito population based on weather conditions was calibrated using real weather and mosquito surveillance data, and validated using a subset of surveillance data. Results showed that WNV vector abundance on any one day could be predicted with reasonable accuracy from relationships with mean degree-days >9 degrees C over the 11 preceding days, and precipitation 35 d previously. This finding provides optimism for the development of weather-generated forecasting for WNV risk that could be used in decision support systems for interventions such as mosquito control.

  2. Evaluation of larvicidal activity of biogenic nanoparticles against filariasis causing Culex mosquito vector

    Science.gov (United States)

    Dhanasekaran, Dharumadurai; Thangaraj, Ramasamy

    2013-01-01

    Objective To evaluate the larvicidal activity of biogenic nanoparticles against filariasis causing Culex mosquito vector. Methods The synthesized AgNPs were characterized by UV-vis. spectrum, Fourier transform infrared and X-ray diffraction. Larvae were exposed to varying concentrations of aqueous extract of synthesized AgNPs for 10 min. The different concentrations of 5, 2.5, 1.25, 0.625 and 0.312 mg/L silver nanoparticles were tested against the Culex larvae. Results The mortality rate of Agaricus bisporus biogenic nanoparticles against Culex larvae are 5 mg/L (100%), 2.5 mg/L (81%), 1.25 mg/L (62%), 0.625 mg/L (28%) and 0.312 mg/L (11%). Conclusions These results suggest that the synthesized biogenic AgNPs have the potential to be used as an ideal eco-friendly approach for controlling Culex larvae.

  3. Evaluation of larvicidal activity of biogenic nanoparticles against filariasis causing Culex mosquito vector

    Directory of Open Access Journals (Sweden)

    Dharumadurai Dhanasekaran

    2013-06-01

    Full Text Available Objective: To evaluate the larvicidal activity of biogenic nanoparticles against filariasis causing Culex mosquito vector. Methods: The synthesized AgNPs were characterized by UVvis. spectrum, Fourier transform infrared and X-ray diffraction. Larvae were exposed to varying concentrations of aqueous extract of synthesized AgNPs for 10 min. The different concentrations of 5, 2.5, 1.25, 0.625 and 0.312 mg/L silver nanoparticles were tested against the Culex larvae. Results: The mortality rate of Agaricus bisporus biogenic nanoparticles against Culex larvae are 5 mg/L (100%, 2.5 mg/L (81%, 1.25 mg/L (62%, 0.625 mg/L (28% and 0.312 mg/L (11%. Conclusions: These results suggest that the synthesized biogenic AgNPs have the potential to be used as an ideal eco-friendly approach for controlling Culex larvae.

  4. Climate-based models for West Nile Culex mosquito vectors in the Northeastern US

    Science.gov (United States)

    Gong, Hongfei; Degaetano, Arthur T.; Harrington, Laura C.

    2011-05-01

    Climate-based models simulating Culex mosquito population abundance in the Northeastern US were developed. Two West Nile vector species, Culex pipiens and Culex restuans, were included in model simulations. The model was optimized by a parameter-space search within biological bounds. Mosquito population dynamics were driven by major environmental factors including temperature, rainfall, evaporation rate and photoperiod. The results show a strong correlation between the timing of early population increases (as early warning of West Nile virus risk) and decreases in late summer. Simulated abundance was highly correlated with actual mosquito capture in New Jersey light traps and validated with field data. This climate-based model simulates the population dynamics of both the adult and immature mosquito life stage of Culex arbovirus vectors in the Northeastern US. It is expected to have direct and practical application for mosquito control and West Nile prevention programs.

  5. Lysinibacillus sphaericus S-layer protein toxicity against Culex quinquefasciatus.

    Science.gov (United States)

    Lozano, Lucía C; Ayala, Juan A; Dussán, Jenny

    2011-10-01

    The main toxicity mechanism of Lysinibacillus sphaericus, which is used in the control of mosquitoes, is its binary toxin produced during sporulation; additionally the Mtx1, Mtx2 and Mtx 3 toxins are expressed in vegetative cells. Mosquito larvicidal potency of the S-layer protein that is expressed in vegetative cells has been determined. The protein is similar to other S-layer proteins of mosquitocidal L. sphaericus strains. The LC50 values of the S-layer protein of the L. sphaericus OT4b25, OT4b26, and III(3)7 strains against third-instar larvae of Culex quinquefasciatus were 8.7, 24 and 0.68 μg/ml, respectively. To our knowledge this is the first study showing the mosquito larvicidal potency of the S-layer protein from Lysinibacillus sphaericus.

  6. Dieldrin-resistance in Culex pipiens fatigans in Malaya

    Science.gov (United States)

    Wharton, R. H.

    1958-01-01

    Resistance to insecticides in Culex pipiens fatigans has already been reported from two areas in Malaya. In Penang two years' use of BHC as a larvicide resulted in the development of a strain which was found to have acquired a tenfold resistance to BHC, and also to dieldrin to which it had not been exposed. In Singapore, when larval control became unsatisfactory after 6 months' use of a dieldrin emulsion, laboratory experiments confirmed that active resistance to dieldrin had developed. The present observations report the finding of two further dieldrin-BHC resistant strains of C. p. fatigans in Malaya, but differ from the previous reports in that resistance, in one strain at least, was developed as a result of house-spraying with dieldrin against adult mosquitos. In this strain resistance to dieldrin was about 100 times in both adults and larvae, resistance to gamma-BHC in larvae was about 20 times, while resistance to DDT was slight. PMID:13536808

  7. Evaluation of different formulations of IGRs against Aedes albopictus and Culex quinquefasciatus (Diptera: Culicidae)

    OpenAIRE

    Gul Zamin Khan; Inamullah Khan; Imtiaz Ali Khan; Alamzeb; Muhammad Salman; Kalim Ullah

    2016-01-01

    Objective: To test the relative efficacy of pyriproxyfen and methoprene on mortality, deformity, inhibition and emergence to adult stages of Culex quinquefasciatus and Aedes albopictus. Methods: Serial dilutions (0.01–0.05 mg/L) of methoprene, pyriproxyfen 0.5 water dispersible granules (WDG) and pyriproxyfen 1.0 WDG were used to assess mortality and inhibition of 3rd instar larvae of Aedes albopictus and Culex quinquefasciatus. Each concentration and control was replicated four times in c...

  8. The Genus Culex, Subgenus Eumelanomyia Theobald in Southeast Asia and Adjacent Areas

    Science.gov (United States)

    1972-01-01

    Bore1 1930, Mon. Coil. Sot. Path. exot. 3: 365 (d*, ?, L*). Culex macropus Blanchard 1905, Les Moustiques :327. New name for Culex Zongifies Theobald...Spec. Pub. 111, 147 pp. BOREL, E. 1926. Les Moustiques de la Cochinchine et du Sud-Annam. (I), Arch. Inst. Pasteur d’Indochine. 47 pp. 1930. Les... Moustiques de la Cochinchine et du Sud-Annam. Mon. Coll. Sot. Pat. exot. 3, 423 pp. BRAM, R A. 1967. Contributions to the mosquitoes of Southeast Asia

  9. Acute toxicity of furazolidone on Artemia salina, Daphnia magna, and Culex pipiens molestus larvae

    Energy Technology Data Exchange (ETDEWEB)

    Macri, A.; Stazi, A.V.; Dojmi di Delupis, G.

    1988-10-01

    As a result of evidence of the ecotoxicity of nitrofurans, the acute toxicity of furazolidone was tested in vivo on two aquatic organisms, Artemia salina and Daphnia magna, which are both crustaceans. Toxicity studies were also performed on larvae of Culex pipiens molestus. Results indicated a significant toxicity of the compound on Culex pipiens and Daphnia magna, while Artemia salina proved to be the least sensitive.

  10. RNA Splicing in a New Rhabdovirus from Culex Mosquitoes▿†

    OpenAIRE

    KUWATA, Ryusei; Isawa, Haruhiko; Hoshino, Keita; Tsuda, Yoshio; Yanase, Tohru; Sasaki, Toshinori; Kobayashi, Mutsuo; Sawabe, Kyoko

    2011-01-01

    Among members of the order Mononegavirales, RNA splicing events have been found only in the family Bornaviridae. Here, we report that a new rhabdovirus isolated from the mosquito Culex tritaeniorhynchus replicates in the nuclei of infected cells and requires RNA splicing for viral mRNA maturation. The virus, designated Culex tritaeniorhynchus rhabdovirus (CTRV), shares a similar genome organization with other rhabdoviruses, except for the presence of a putative intron in the coding region for...

  11. Biological control of Culex (Culex) saltanensis Dyar, (Diptera, Culicidae) through Bacillus thuringiensis israelensis in laboratory and field conditions Controle biológico de Culex (Culex) saltanensis Dyar, (Diptera, Culicidae) através de Bacillus thuringiensis israelensis em condições de laboratório e campo

    OpenAIRE

    Zequi,João A. C.; José Lopes

    2007-01-01

    Culex (Culex) saltanensis Dyar, 1928 can become a problem in urban centers because they reproduce abundantly in ponds organically enriched. It is vector of the Plasmodium spp. and Crithidia ricadoi Sibajev et al. 1993. This research verifies the efficacy of Bacillus thuringiensis israelensis on C. saltanensis in two temperature situations, both in laboratory and field conditions. LC50 for C. saltanensis immatures fourth instar, was 0.154 ppm and the LC95 was 0.248 ppm an average temperature o...

  12. Lectin Activity in Gut Extract of Culex Pipiens

    Directory of Open Access Journals (Sweden)

    Mona Koosha

    2013-03-01

    Full Text Available Background: The role of lectins is important in interaction between pathogens and mosquito vectors. This study was performed to identify agglutinin activities of protein molecules on the midgut of Culex pipiens. Methods: Culex pipiens was reared in insectray condition and the midguts of males and females (blood fed and un­fed were dissected separately in Tris-HCl buffer. The extracts of midguts were applied for hemagglutinin assay against red blood cells of rabbit, mouse, rat, dog, horse, sheep, guinea pig, cow, human (A, B, AB, O groups. Then, the RBCs with relatively high agglutinin activity were chosen for carbohydrate inhibition assay. D (+ glucose, D (+ galactose, D (+ mannose, D (- fructose, D (- arabinose, L (- fucose, lactose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, sialic acid were used to specify carbohydrate binding lectin.Results: The highest agglutinin activities were found against sheep and rabbits RBCs. Sexual diversity of agglutinin activities was observed among midgut extraction of males and females. In addition, variation in agglutinin activity of blood fed and unfed female mosquitoes were detected. The lectin activity was inhibited highly with glucose, galactose, fucose and fructose but less inhibitor activities was observed by arabinose, N-acetyl-D-galactosamine, n-acetyl-d-glucosamine, lactose and mannose.Conclusion: The secretion of hemagglutinins (lectins or lectin-like molecules in the digestive system depends on the type of food in the gut. This suggests that emptying of the gut in preparation for protein rich food probably starts the secretion of hemagglutinins.

  13. Phytochemical composition, mosquito larvicidal, ovicidal and repellent activity of Calotropis procera against Culex tritaeniorhynchus and Culex gelidus

    Directory of Open Access Journals (Sweden)

    Gaurav Kumar

    2012-03-01

    Full Text Available Focus of this study was to determine the phytochemical composition and mosquito controlling potential of aqueous extract of Calotropis procera (Ait. R.Br. leaves using in vitro methods. Preliminary phytochemical analysis of the extract showed the presence of phenolic compounds, flavonoids, alkaloids, tannins, saponins, glycosides and phytosterols as major phytochemical groups. Aqueous extract of C. procera leaves (1,000 ppm exhibited 100% larvicidal activity against fourth instar larvae of Culex tritaeniorhynchus and Cx. gelidus. Extract treatment (1,000 ppm of both mosquitoes’ eggs resulted in to 100% ovicidal activity. At 1,000 ppm, extract provided complete protection from mosquito bite for 240 min against both mosquitoes; however at lower doses the protection time was less. The findings of the current study emphasise the potentiality of C. procera leaves for controlling the mosquito population and their possible way in the developing the natural insecticide for the control of Cx. tritaeniorhynchus and Cx. gelidus mosquitoes.

  14. Oviposition preferences of Culex restuans and Culex pipiens (Diptera: Culicidae) for selected infusions in oviposition traps and gravid traps.

    Science.gov (United States)

    Jackson, Bryan T; Paulson, Sally L; Youngman, Roger R; Scheffel, Sabra L; Hawkins, Belinda

    2005-12-01

    Field studies were conducted in southwestern Virginia to determine the ovipositional preferences of Culex restuans and Culex pipiens by using ovitraps and gravid traps baited with selected infusions. For the ovitrap collections, 4 different infusions (manure, hay, grass, and rabbit chow) were used. Significant differences among infusions were detected on most sample dates for both species. For 3 of the first 4 wk of collections, the manure infusion collected significantly more Cx. restuans than all the other infusions. The hay and grass infusions collected the majority of the egg rafts during weeks 5-9. Cx. pipiens egg rafts were absent from the first 3 wk of collections. Of the remaining 6 wk, 4 showed significant differences in attractiveness of infusions, with the hay and grass infusions preferred by Cx. pipiens. Two infusions, manure and hay, were used for the gravid trap experiment and both Cx. restuans and Cx. pipiens data were combined for analysis. Only the first 2 wk showed significance, with manure being preferred over hay in both weeks. In later collections, the relative attractiveness of the hay infusion increased. A seasonal shift in infusion preference may be related to incubation temperature during preparation of the infusions. New infusions were prepared each week and incubation was done outside. Increased attractiveness of the hay infusion coincided with higher average temperatures in July and August. Hay infusion was very effective for trapping both Cx. pipiens and Cx. restuans in southwestern Virginia and is more convenient to use than manure. However, cool outside temperatures in the early season may interfere with the fermentation process and thus incubation should be done for a longer time or brought indoors.

  15. Development of a Bacillus sphaericus tablet formulation and its evaluation as a larvicide in the biological control of Culex quinquefasciatus

    National Research Council Canada - National Science Library

    Flávia P. Morais de Medeiros; Maria Alice Varjal de Melo Santos; Leda Regis; Eugênia M. Maranhão Rios; Pedro J. Rolim Neto

    2005-01-01

    ...; physical, chemical, and biological analysis of the active powder (solubility, residual humidity, particle size, resting angle, flowing off time, compacted density, and biological activity against Culex quinquefasciatus larvae...

  16. Culex pipiens s.l. and Culex torrentium (Culicidae) in Wrocław area (Poland): occurrence and breeding site preferences of mosquito vectors.

    Science.gov (United States)

    Weitzel, Thomas; Jawień, Piotr; Rydzanicz, Katarzyna; Lonc, Elzbieta; Becker, Norbert

    2015-01-01

    Both ornithophilic mosquito species, Culex pipiens s.l. (L.) and Culex torrentium (Martini, 1925), occur sympatric in temperate Europe. They are presumed to be primary vectors of West Nile and Sindbis viruses. Differentiation of these morphologically similar Culex species is essential for evaluation of different vector roles, for mosquito surveillance and integrated control strategies. Cx. torrentium has been neglected or erroneously determined as Cx. pipiens s.l. in some previous studies, because only males of both species can be diagnosed reliably by morphology. Thus, knowledge about species abundance, geographical distribution, breeding site preferences and the zoonotic risk assessment is incomplete also in Poland. In Wrocław area (Silesian Lowland), besides typical urban breeding sites, huge sewage irrigation fields provide suitable breeding conditions for Culex species. They are also inhabited by 180 resident and migratory bird species serving as potential virus reservoirs. In this study, morphology of larvae and males as well as species diagnostic enzyme markers, namely adenylate kinase (AK) and 2-hydroxybutyrate dehydrogenase (HBDH), were used to discriminate Cx. pipiens s.l. and Cx. torrentium. In a total of 650 Culex larvae from 24 natural and artificial breeding sites, Cx. pipiens s.l. had a proportion of 94.0% and Cx. torrentium only 6.0%. It could be shown that both species are well adapted to various breeding site types like ditches, catch basins, flower pots and buckets with diverse water quality. Cx. torrentium preferred more artificial water containers in urban surrounding (12% species proportion), whereas in semi-natural breeding sites, Cx. torrentium was rare (3%). In 12 of 24 breeding sites, larvae of both species have been found associated.

  17. Dynamics of Aedes aegypti and Culex quinquefasciatus in septic tanks.

    Science.gov (United States)

    Mackay, Andrew J; Amador, Manuel; Diaz, Annette; Smith, Josh; Barrera, Roberto

    2009-12-01

    Aedes aegypti and Culex quinquefasciatus were found in large numbers emerging from septic tanks in southern Puerto Rico during the dry season. Previous studies suggested that Ae. aegypti uses subterranean aquatic habitats only during dry periods when surface containers do not have water. This research investigated whether septic tanks are alternative aquatic habitats that this mosquito uses during unfavorable times of the year, or whether Ae. aegypti uses this aquatic habitat throughout the year. To assess temporal change, exit traps were used to collect mosquitoes emerging from septic tanks in Playa/Playita, southern Puerto Rico, from November 2006 to October 2007. We also investigated the hypotheses that (1) the production of Ae. aegypti in septic tanks was larger than in surface containers and (2) adult mosquitoes emerging from septic tanks were larger than those emerging from surface containers. This study demonstrated that unsealed septic tanks produced large numbers of Ae. aegypti and Cx. quinquefasciatus throughout the year, without any significant relationship with rainfall. The number of adult Ae. aegypti emerging per day from septic tanks in each community was 3 to 9 times larger than those produced in surface containers. It was also demonstrated that Ae. aegypti emerging from septic tanks were significantly larger than those emerging from surface container habitats. It is recommended that dengue prevention programs include regular inspection and maintenance of septic tanks in communities lacking sewerage.

  18. West Nile Virus lineage-2 in Culex specimens from Iran.

    Science.gov (United States)

    Shahhosseini, Nariman; Chinikar, Sadegh; Moosa-Kazemi, Seyed Hassan; Sedaghat, Mohammad Mehdi; Kayedi, Mohammad Hassan; Lühken, Renke; Schmidt-Chanasit, Jonas

    2017-10-01

    Screening of mosquitoes for viruses is an important forecasting tool for emerging and re-emerging arboviruses. Iran has been known to harbour medically important arboviruses such as West Nile virus (WNV) and dengue virus (DENV) based on seroepidemiological data. However, there are no data about the potential mosquito vectors for arboviruses in Iran. This study was performed to provide mosquito and arbovirus data from Iran. A total of 32 317 mosquitos were collected at 16 sites in five provinces of Iran in 2015 and 2016. RT-PCR for detection of flaviviruses was performed. The PCR amplicons were sequenced, and 109 WNV sequences, including one obtained in this study, were used for phylogenetic analyses. The 32 317 mosquito specimens belonging to 25 species were morphologically distinguished and distributed into 1222 pools. Culex pipiens s.l. comprised 56.429%. One mosquito pool (0.08%), containing 46 unfed Cx. pipiens pipiens form pipiens (Cpp) captured in August 2015, was positive for flavivirus RNA. Subsequent sequencing and phylogenetic analyses revealed that the detected Iranian WNV strain belongs to lineage 2 and clusters with a strain recently detected in humans. No flaviviruses other than WNV were detected in the mosquito pools. Cpp could be a vector for WNV in Iran. Our findings indicate recent circulation of WNV lineage-2 strain in Iran and provide a solid base for more targeted arbovirus surveillance programs. © 2017 John Wiley & Sons Ltd.

  19. Efficacy of female Culex quinquefasciatus with entomopathogenic fungus Fusarium pallidoroseum.

    Science.gov (United States)

    Mohanty, Suman Sundar; Raghavendra, Kamaraju; Rai, Usha; Dash, Aditya Prasad

    2008-06-01

    This study was conducted to isolate and identify natural entomopathogenic fungi from female Culex quinquefasciatus and to test their adulticidal activity. Field-collected female C. quinquefasciatus died early and were placed on a Saboraud's dextrose agar plates for growth and isolation of natural entomopathogenic fungi. The plates were maintained in an incubator at 24+/-2 degrees C for 3 days. Four fungal species were isolated in two genera namely, Aspergillus and Fusarium. The identified fungal species were A. niger, A. flavus, A. nidulans var acristatus (ITCC-6327.04), and F. pallidoroseum (ITCC-6324.06). Adult bioassays were carried out using spore-impregnated paper in WHO-holding tubes. F. pallidoroseum was found to be more effective than the others. Exposure of C. quinquefasciatus to spores of A. flavus and A. niger for 4 h caused 5.53% and 5.51% mortality in the mosquitoes within a week, respectively. All the female C. quinquefasciatus were killed within 4 days of exposure to F. pallidoroseum at a concentration of 1.11 x 10(10) conidia per m2. Significant difference of longevity was observed between the F. pallidoroseum-treated C. quinquefasciatus and control mosquitoes. The LT50 of F. pallidoroseum was 2.08 days for 4 h exposure to C. quinquefasciatus. Results of the present study confirm that F. pallidoroseum is one of the alternative biological control agents of adult mosquitoes.

  20. Avian host-selection by Culex pipiens in experimental trials.

    Directory of Open Access Journals (Sweden)

    Jennifer E Simpson

    Full Text Available Evidence from field studies suggests that Culex pipiens, the primary mosquito vector of West Nile virus (WNV in the northeastern and north central United States, feeds preferentially on American robins (Turdus migratorius. To determine the contribution of innate preferences to observed preference patterns in the field, we conducted host preference trials with a known number of adult female C. pipiens in outdoor cages comparing the relative attractiveness of American robins with two common sympatric bird species, European starling, Sternus vulgaris and house sparrow, Passer domesticus. Host seeking C. pipiens were three times more likely to enter robin-baited traps when with the alternate host was a European starling (n = 4 trials; OR = 3.06; CI [1.42-6.46] and almost twice more likely when the alternative was a house sparrow (n = 8 trials; OR = 1.80; CI = [1.22-2.90]. There was no difference in the probability of trap entry when two robins were offered (n = 8 trials. Logistic regression analysis determined that the age, sex and weight of the birds, the date of the trial, starting-time, temperature, humidity, wind-speed and age of the mosquitoes had no effect on the probability of a choosing a robin over an alternate bird. Findings indicate that preferential feeding by C. pipiens mosquitoes on certain avian hosts is likely to be inherent, and we discuss the implications innate host preferences may have on enzootic WNV transmission.

  1. Oviposition Attractancy of Bacterial Culture Filtrates: response of Culex quinquefasciatus

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    S Poonam

    2002-04-01

    Full Text Available Oviposition attractants could be used for monitoring as well as controlling mosquitoes by attracting them to lay eggs at chosen sites. In the present study, culture filtrates of seven bacterial species were tested for their attractancy against gravid females of Culex quinquefasciatus. When their oviposition active indices (OAI were studied, the culture filtrates of Bacillus cereus and Pseudomonas fluorescens exhibited oviposition attractancy (OAI = >0.3 at 100 ppm and the OAI were respectively 0.70 and 0.47. Culture filtrates of B. thuringiensis var. israelensis (wild type, B. t. var. israelensis (mutant and B. sphaericus showed attractancy at 2000 ppm with OAI of respectively 0.71, 0.59 and 0.68. However, the OAI of B. megaterium as well as Azospirillum brasilense was 0.13 (at 2000 ppm, which was less than 0.3 required to be considered them as attractants. When the oviposition attractancy of the bacterial culture filtrates were compared with that of a known oviposition attractant, p-cresol (at 10 ppm, the culture filtrates of B. t. var. israelensis (wild type and B. cereus were found to be more active than p-cresol, respectively with 64.2 and 54.3% oviposition.

  2. Repellent effect of Lagenaria siceraria extracts against Culex pipiens.

    Science.gov (United States)

    Hassan, Mostafa I; Fouda, Mohamad A; Hammad, Kotb M; Tanani, Mohamad A; Shehata, Ahmed Z

    2014-04-01

    Ethanolic, acetone and petroleum ether extracts from leaves and stems of Lagenaria siceraria (Cucurbitaceae) were screened for their repellency effect against Culex pipiens L. mosquito. The repellent action of the present plant extracts were varied depending on the plant parts and the dose of extract. The petroleum ether extract of leaves showed the same repellency percent (100%) of commercial formulation, N. N.diethyl toulamide (DEET) at the higher dose (3.33 mg/cm2), while petroleum ether extract from stems exhibiting the repellent action (89.6%) at the same dose, respectively. Ethanolic extracts of leaves and stems exhibited the lowest repellent activity as it recorded (81.3% and 69.1%) at (6.67 mg/cm2), respectively. Results of this study may contribute to design an alternative way to control mosquitoes currently based on applications of synthetic insecticides. These extracts could be developed commercially as an effective personal protection measure against mosquito bites and thus to control diseases caused by mosquito-borne pathogens.

  3. Evaluation of Bacillus sphaericus bioinsecticide produced with white soybean meal as culture medium for the control of Culex (Culex) quinquefasciatus.

    Science.gov (United States)

    Melo, André L A; Soccol, Carlos R; Thomaz-Soccol, Vanete; Nogueira, Miodeli

    2009-03-01

    Bioinsecticides are shown to be useful in control programs to prevent several diseases, based on their specificity and efficiency against insect vectors. In the current study a bioinsecticide based on Bacillus sphaericus was produced using a white soybean culture medium and applied to larvae of Culex quinquefasciatus, the susceptible species, and Aedes aegypti, the refractory species used as the negative control. Efficacy was compared with that of the product fermented with the Luria Bertani (LB) reference medium. The experiments showed that C. quinquefasciatus was highly susceptible to the product prepared with white soybean meal, reaching 100% larval mortality even at 10mg/L, while A. aegypti failed to reach 70% mortality at a concentration of 1g/L. By comparison with the reference medium, the proposed culture medium showed high larvicidal power, reaching a LD90 of 2.26 mg/L, while 4.37 mg/L was needed for the LB medium to achieve the same mortality rate. Cost comparison between the formulations favored the use of the bioinsecticide produced with white soybean meal. After factoring in the LD90 value, the cost ratio favored the new raw material by nearly 1:220.

  4. Bionomics of Culex quinquefasciatus within urban areas of Rio de Janeiro, Southeastern Brazil

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    Mariana Rocha David

    2012-10-01

    Full Text Available OBJECTIVE: To evaluate density, parity rates, daily survival and longevity of natural populations of Culex quinquefasciatus in three neighborhoods with distinct socio-economic and infrastructure profiles. METHODS: Mosquito collections of the Culex quinquefasciatus species were performed weekly during two four month periods, from August to November 2008 (spring and March to June 2009 (fall, in a favela (slum, a suburban area and a middle class area of Rio de Janeiro, Southeastern Brazil. Collections were performed with backpack aspirators, in 20 randomly selected houses in each area per week, during 15-20 minutes per house. Ovaries were removed from captured females and classified as initial, intermediary or final stage. Furthermore, females were dissected for determination of parity based on the condition of the tracheal system. Mosquito survival rate and longevity were estimated on a per month basis for each neighborhood. RESULTS: We collected a total of 2,062 Culex quinquefasciatus, but monthly vector density was not correlated with temperature and rainfall. We dissected the ovaries of 625 Culex quinquefasciatus, and overall, there was a higher proportion of nulliparous females during the dryer months, while gravid females were more frequent in rainy months. In the middle class neighborhood, the parity rate reached up to 93.75% with survivorship of 0.979. Lower parity and survival rates were obtained in the suburban area (as low as 36.4% parity and 0.711 daily survival. Up to 84.7% of Culex quinquefasciatus females could survive the eight day period needed to complete West Nile Virus incubation. CONCLUSIONS: The survival rate of Culex quinquefasciatus varied significantly between the neighborhoods. This suggests that vectorial capacity and disease transmission risk may vary greatly between different urban areas, which is potentially useful information for vector control programs.

  5. Larval habitat dynamics and diversity of Culex mosquitoes in rice agro-ecosystem in Mwea, Kenya.

    Science.gov (United States)

    Muturi, Ephantus J; Shililu, Josephat I; Gu, Weidong; Jacob, Benjamin G; Githure, John I; Novak, Robert J

    2007-01-01

    Introduction of irrigation projects in developing nations has often been blamed for aggravating the problem of mosquito-borne diseases by creating ideal larval habitats for vector mosquitoes. However, whereas several studies have demonstrated the relationship between malaria vectors and irrigation, little work has been done on culicine mosquitoes despite their potential in transmission of filariasis and arboviruses and their significant biting nuisance in these areas. This study examined the diversity of Culex mosquito fauna and their larval habitats at two sites (Murinduko and Kiamachiri) in Mwea, Kenya over a 12-month period. The habitat types present at each site within a 200-meter radius around the study village, including randomly selected paddies and canals, were sampled every two weeks to examine the relationship between vegetation cover, water depth, turbidity, and Culex larval counts. Ten culicine species belonging to four genera were identified, with 73.1% of the total collection comprising of Culex duttoni and Cx. quinquefasciatus. Other species collected included Cx. annulioris, Cx. poicilipes, Cx. cinereus, Cx. tigripes, Cx. trifilatus, Aedes spp., Coquilettidia fuscopennata, and Ficalbia splendens. Murinduko was more diverse than Kiamachiri in terms of species richness (10 versus 7 species) and larval habitat diversity (11 versus 8 habitat types). Paddies, canals, and rain pools were the most diverse habitats in terms of species richness, and ditches, rock pools, and tree holes were the least diverse. Principal component and correlation analyses showed a strong association between three Culex species and the measured habitat characteristics. Culex poicilipes was strongly associated with floating vegetation, Cx. annulioris with clean water containing emergent vegetation, and Cx. quinquefasciatus was associated with turbid water. Seasonal changes in larval counts in water reservoirs and pool and ditch habitats were closely associated with rainfall

  6. Toksisitas Bacillus sphaericus H-5a5b (VCRC B42) terhadap larva Culex quiquefascitus

    OpenAIRE

    Salamun Salamun; Rosmaida Rosmaida; Ni'matuzzahroh Ni'matuzzahroh; R.A Samsumaharto

    1996-01-01

    Bacillus sphaericus H-5a5b is an entomoathogenic agent which showing high potency for vector control, highly specific to insect target, and do not produce any adverse environmental impact. Such agent would be promising for vector control in Indonesia. The present studies is aimed to observing the toxicity status of Bacillus sphaericus H-5a5b (VCRC B42) against Culex quiquefascitus larvae. The larvae of Culex quiquefascitus were reared under the laboratory conditions. The powder of VCRC B42 we...

  7. Identification of Culex (Melanoconion) species of the United States using female cibarial armature (Diptera: Culicidae).

    Science.gov (United States)

    Williams, Martin R; Savage, Harry M

    2009-07-01

    Species within the subgenus Culex (Melanoconion) Theobald are the primary enzootic vectors of viruses in the Venezuelan equine encephalitis complex including Everglades virus, and probable enzootic vectors of eastern equine encephalitis and West Nile viruses. Adult females of this subgenus are often difficult or impossible to identify to species based on external morphological characters. The use of female cibarial armature allows for the identification of field-collected adult female specimens of Culex (Melanoconion). The cibarial armatures are described and illustrated for all species from the United States and a key to species using this character is presented.

  8. Midgut Microbial Community of Culex quinquefasciatus Mosquito Populations from India

    Science.gov (United States)

    Chandel, Kshitij; Mendki, Murlidhar J.; Parikh, Rasesh Y.; Kulkarni, Girish; Tikar, Sachin N.; Sukumaran, Devanathan; Prakash, Shri; Parashar, Brahma D.; Shouche, Yogesh S.; Veer, Vijay

    2013-01-01

    The mosquito Culex quinquefasciatus is a ubiquitous species that serves as a major vector for west nile virus and lymphatic filariasis. Ingestion of bloodmeal by females triggers a series of physiological processes in the midgut and also exposes them to infection by these pathogens. The bacteria normally harbored in the midgut are known to influence physiology and can also alter the response to various pathogens. The midgut bacteria in female Cx. quinquefasciatus mosquitoes collected over a large geographical area from India was studied. Examination of 16S ribosomal DNA amplicons from culturable microflora revealed the presence of 83 bacterial species belonging to 31 bacterial genera. All of these species belong to three phyla i.e. Proteobacteria, Firmicutes and Actinobacteria. Phylum Proteobacteria was the most dominant phylum (37 species), followed by Firmicutes (33 species) and Actinobacteria (13 species). Phylum Proteobacteria, was dominated by members of γ-proteobacteria class. The genus Staphylococcus was the largest genus represented by 11 species whereas Enterobacter was the most prevalent genus and recovered from all the field stations except Leh. Highest bacterial prevalence was observed from Bhuj (22 species) followed by Nagrota (18 species), Masimpur (18 species) and Hathigarh (16 species). Whereas, least species were observed from Leh (8 species). It has been observed that individual mosquito harbor extremely diverse gut bacteria and have very small overlap bacterial taxa in their gut. This variation in midgut microbiota may be one of the factors responsible for variation in disease transmission rates or vector competence within mosquito population. The present data strongly encourage further investigations to verify the potential role of the detected bacteria in mosquito for the transmission of lymphatic filariasis and west nile virus. To the best of our knowledge this is the first study on midgut microbiota of wild Cx. quinquefasciatus from over a

  9. Energetic cost of insecticide resistance in Culex pipiens mosquitoes.

    Science.gov (United States)

    Rivero, A; Magaud, A; Nicot, A; Vézilier, J

    2011-05-01

    The extensive use of insecticides to control vector populations has lead to the widespread development of different mechanisms of insecticide resistance. Mutations that confer insecticide resistance are often associated to fitness costs that prevent them from spreading to fixation. In vectors, such fitness costs include reductions in preimaginal survival, adult size, longevity, and fecundity. The most commonly invoked explanation for the nature of such pleiotropic effects of insecticide resistance is the existence of resource-based trade-offs. According to this hypothesis, insecticide resistance would deplete the energetic stores of vectors, reducing the energy available for other biological functions and generating trade-offs between insecticide resistance and key life history traits. Here we test this hypothesis by quantifying the energetic resources (lipids, glycogen, and glucose) of larvae and adult females of the mosquito Culex pipiens L. resistant to insecticides through two different mechanisms: esterase overproduction and acetylcholinesterase modification. We find that, as expected from trade-off theory, insecticide resistant mosquitoes through the overproduction of esterases contain on average 30% less energetic reserves than their susceptible counterparts. Acetylcholinesterase-modified mosquitoes, however, also showed a significant reduction in energetic resources (20% less). We suggest that, in acetylcholinesterase-modified mosquitoes, resource depletion may not be the result of resource-based trade-offs but a consequence of the hyperactivation of the nervous system. We argue that these results not only provide a mechanistic explanation for the negative pleiotropic effects of insecticide resistance on mosquito life history traits but also can have a direct effect on the development of parasites that depend on the vector's energetic reserves to fulfil their own metabolic needs.

  10. Evaluation of different formulations of IGRs against Aedes albopictus and Culex quinquefasciatus (Diptera: Culicidae

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    Gul Zamin Khan

    2016-06-01

    Conclusions: It is thus concluded that IGRs can be utilized as environment friendly control measures for Culex and Aedes spp. of mosquitoes on small and large scale. This will reduce the use of conventional insecticides by the public health authorities and help in reducing selection pressure of insecticides.

  11. Control of pyrethroid-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes with chlorfenapyr in Benin

    NARCIS (Netherlands)

    N'Guessan, R.; Boko, P.; Odjo, A.; Knols, B.G.J.; Akogbeto, M.; Rowland, M.

    2009-01-01

    Objective To compare the efficacy of chlorfenapyr applied on mosquito nets and as an indoor residual spray against populations of Anopheles gambiae and Culex quinquefasciatus in an area of Benin that shows problematic levels of pyrethroid resistance. Method Eight-week trial conducted in experimental

  12. Chemical ecology of the behaviour of the filariasis mosquito Culex quinquefasciatus Say

    NARCIS (Netherlands)

    Mboera, L.E.G.

    1999-01-01

    Culex quinquefasciatus is an important vector of urban bancroftian filariasis in the tropical world. Despite its public health importance, much of its olfactory mediated behaviour is poorly understood. Studies on resource-location behaviour, in particular the role of semiochemicals in its behaviour,

  13. Considerations for accurate identification of adult Culex restuans (Diptera: Culicidae) in field studies.

    Science.gov (United States)

    Harrington, Laura C; Poulson, Rebecca L

    2008-01-01

    Understanding the ecology and behavior of different mosquito species (Diptera: Culicidae) is essential for identifying their role in disease transmission cycles and public health risk. Two species of Culex mosquitoes in the northeastern United States, Culex pipiens L. and Culex restuans Theobald, have been implicated in enzootic transmission of West Nile virus (family Flaviviridae, genus Flavivirus, WNV). Despite the difficulty of differentiating these two species as adults, many public health workers and vector biologists collecting adults in the field separate these species based on external morphology. This approach is often used rather than examination of dissected male genitalia or polymerase chain reaction (PCR)-based diagnostics due to time or cost constraints. We evaluated the reliability of seven published morphological characters to differentiate adults of these species by comparing blindly scored morphology with PCR-based confirmations. Our study demonstrates that morphological identification of Cx. pipiens is marginal and often not reliable for Cx. restuans. We also examined error rates with molecular-based approaches. DNA samples were contaminated with as little as one leg from another species. We conclude that to fully understand the respective roles of Culex species in the epidemiology of WNV and other pathogens, more attention should be paid to these considerations for accurate species identification.

  14. Susceptibility of a North American Culex quinquefasciatus to Japanese encephalitis virus

    Science.gov (United States)

    Japanese encephalitis virus (JEV) is a flavivirus that is transmitted by Culex (Cx.) tritaeniorhynchus in tropical and subtropical regions of Asia. The endemic transmission cycle involves domestic pigs and avian species that serve as amplification hosts; humans are incidental hosts that cannot devel...

  15. Larvicidal Activity of Nerium oleander against Larvae West Nile Vector Mosquito Culex pipiens (Diptera: Culicidae)

    Science.gov (United States)

    El-Akhal, Fouad; Guemmouh, Raja; Ez Zoubi, Yassine; El Ouali Lalami, Abdelhakim

    2015-01-01

    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. PMID:26640701

  16. Control of pyrethroid-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes with chlorfenapyr in Benin

    NARCIS (Netherlands)

    N'Guessan, R.; Boko, P.; Odjo, A.; Knols, B.G.J.; Akogbeto, M.; Rowland, M.

    2009-01-01

    Objective To compare the efficacy of chlorfenapyr applied on mosquito nets and as an indoor residual spray against populations of Anopheles gambiae and Culex quinquefasciatus in an area of Benin that shows problematic levels of pyrethroid resistance. Method Eight-week trial conducted in experimental

  17. Toksisitas Bacillus sphaericus H-5a5b (VCRC B42 terhadap larva Culex quiquefascitus

    Directory of Open Access Journals (Sweden)

    Salamun Salamun

    1996-12-01

    Full Text Available Bacillus sphaericus H-5a5b is an entomoathogenic agent which showing high potency for vector control, highly specific to insect target, and do not produce any adverse environmental impact. Such agent would be promising for vector control in Indonesia. The present studies is aimed to observing the toxicity status of Bacillus sphaericus H-5a5b (VCRC B42 against Culex quiquefascitus larvae. The larvae of Culex quiquefascitus were reared under the laboratory conditions. The powder of VCRC B42 were prepared by Vector Control Research Centre (VCRC, India. Bioassays on VCRC B42 agains larvae of Culex quiquefascitus were also carried out under the laboratory conditions. The value of LD50 and LT50 for VCRC B42 were decided using probit analysis. The toxicity status was compared with standart of VCRC India. The result of the bioassays showed that the VCRC B42 was moderately toxic agains larvae of the Culex quiquefascitus. The value of LD50 for VCRC B42 was 0.058 mg/l and LT50 about 27 hours.

  18. Chemical ecology of the behaviour of the filariasis mosquito Culex quinquefasciatus Say

    NARCIS (Netherlands)

    Mboera, L.E.G.

    1999-01-01

    Culex quinquefasciatus is an important vector of urban bancroftian filariasis in the tropical world. Despite its public health importance, much of its olfactory mediated behaviour is poorly understood. Studies on resource-location behaviour, in particular the role of

  19. Laboratory evaluation of lactic acid on attraction of Culex spp. (Diptera: Culicidae).

    Science.gov (United States)

    Allan, Sandra A; Bernier, Ulrich R; Kline, Daniel L

    2010-12-01

    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.

  20. SR450 and Superhawk XP applications of Bacillus thuringiensis israelensis de Barjac against Culex quinquefasciatus Say

    Science.gov (United States)

    Sprayer comparisons and larval morality assays were conducted following SR450 backpack mist blower and Superhawk XP thermal fogger applications of Vectobac® WDG Bacillus thuringiensis israelensis (Bti) de Barjac against Culex quinquefasciatus Say. Bacillus thuringiensis israelensis was applied at m...

  1. Larvicidal Activity of Nerium oleander against Larvae West Nile Vector Mosquito Culex pipiens (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Fouad El-Akhal

    2015-01-01

    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.

  2. Application site and mosquito age influences malathion- and permethrin-induced mortality in Culex quinquefasciatus

    Science.gov (United States)

    Concentrations of malathion and permethrin typical in droplets generated from ultra-low volume and low volume applications were evaluated for efficacy against multiple-aged Culex quinquefasciatus Say, using a topical bioassay. Although during mosquito control operations insecticide droplets will imp...

  3. Taxonomic study and redescription of Culex (Melanoconion theobaldi (Lutz, 1904 (Diptera: Culicidae

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    Oswaldo Paulo Forattini

    1989-01-01

    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".

  4. Insecticide resistance to organophosphates in Culex pipiens complex from Lebanon

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    Osta Mike A

    2012-07-01

    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

  5. Insecticide resistance to organophosphates in Culex pipiens complex from Lebanon

    Science.gov (United States)

    2012-01-01

    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 Ester2 allele, which exhibits

  6. Effects of Forced Egg Retention on the Temporal Progression of West Nile Virus Infection in Culex pipiens quinquefasciatus (Diptera: Culicidae)

    OpenAIRE

    SMARTT, CHELSEA T.; RICHARDS, STEPHANIE L.; Anderson, Sheri L.; Vitek, Christopher J.

    2010-01-01

    Environmental factors that impact the biology of mosquito vectors can have epidemiological implications. Lack of oviposition sites facilitated by environmental factors such as temperature and drought can often force Culex spp. mosquitoes to retain their eggs. Culex pipiens quinquefasciatus Say were fed blood meals containing West Nile virus (WNV; family Flaviviridae, genus Flavivirus) and either allowed to oviposit or forced to retain their eggs through different time points postinfection (9,...

  7. Evaluation of different formulations of IGRs against Aedes albopictus and Culex quinquefasciatus(Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Gul Zamin Khan; Inamullah Khan; Imtiaz Ali Khan; Alamzeb; Muhammad Salman; Kalim Ullah

    2016-01-01

    Objective: To test the relative efficacy of pyriproxyfen and methoprene on mortality,deformity, inhibition and emergence to adult stages of Culex quinquefasciatus and Aedes albopictus.Methods: Serial dilutions(0.01–0.05 mg/L) of methoprene, pyriproxyfen 0.5 water dispersible granules(WDG) and pyriproxyfen 1.0 WDG were used to assess mortality and inhibition of 3rd instar larvae of Aedes albopictus and Culex quinquefasciatus. Each concentration and control was replicated four times in completely randomized design.Data on larval mortality, growth inhibition, deformities and adult’s emergence was recorded weekly. On the basis of best comparative performance, the efficacy of pyriproxyfen 1.0 WDG at 0.1 g/m3 was also tested in the field by collecting treated water samples monthly for 1–6 months after field application. Twenty five 3rd instar larvae of Aedes and Culex spp. of the same cohorts were used for bioassays and compared with larvae in control cups containing 1 L of untreated tap water.Results: Results revealed variations in fatality of different insect growth regulators(IGRs) to the 3rd instar larvae of Culex and Aedes mosquitoes. Among the IGRs, pyriproxyfen 1.0 WDG was found best that exhibited significantly high emergence inhibition against Culex and Aedes spp. Based on the results, the IGRs were classified in terms of the tested parameters in order of pyriproxyfen 1.0 WDG > pyriproxyfen 0.5WDG > methoprene. In case of field studies, pyriproxyfen 1.0 WDG, pool data of the entire target treated sites showed minimum adult emergence from water sampled of habitats treated with 0.1 g/m3 of pyriproxyfen 1.0 WDG.Conclusions: It is thus concluded that IGRs can be utilized as environment friendly control measures for Culex and Aedes spp. of mosquitoes on small and large scale. This will reduce the use of conventional insecticides by the public health authorities and help in reducing selection pressure of insecticides.

  8. Evaluation of different formulations of IGRs against Aedes albopictus and Culex quinquefasciatus (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Gul Zamin Khan; Inamullah Khan; Imtiaz Ali Khan; Alamzeb; Muhammad Salman; Kalim Ullah

    2016-01-01

    Objective: To test the relative efficacy of pyriproxyfen and methoprene on mortality, deformity, inhibition and emergence to adult stages of Culex quinquefasciatus and Aedes albopictus. Methods: Serial dilutions (0.01–0.05 mg/L) of methoprene, pyriproxyfen 0.5 water dispersible granules (WDG) and pyriproxyfen 1.0 WDG were used to assess mortality and inhibition of 3rd instar larvae of Aedes albopictus and Culex quinquefasciatus. Each concentration and control was replicated four times in completely randomized design. Data on larval mortality, growth inhibition, deformities and adult's emergence was recorded weekly. On the basis of best comparative performance, the efficacy of pyr-iproxyfen 1.0 WDG at 0.1 g/m3 was also tested in the field by collecting treated water samples monthly for 1–6 months after field application. Twenty five 3rd instar larvae of Aedes and Culex spp. of the same cohorts were used for bioassays and compared with larvae in control cups containing 1 L of untreated tap water. Results: Results revealed variations in fatality of different insect growth regulators (IGRs) to the 3rd instar larvae of Culex and Aedes mosquitoes. Among the IGRs, pyr-iproxyfen 1.0 WDG was found best that exhibited significantly high emergence inhibition against Culex and Aedes spp. Based on the results, the IGRs were classified in terms of the tested parameters in order of pyriproxyfen 1.0 WDG > pyriproxyfen 0.5 WDG > methoprene. In case of field studies, pyriproxyfen 1.0 WDG, pool data of the entire target treated sites showed minimum adult emergence from water sampled of habitats treated with 0.1 g/m3 of pyriproxyfen 1.0 WDG. Conclusions: It is thus concluded that IGRs can be utilized as environment friendly control measures for Culex and Aedes spp. of mosquitoes on small and large scale. This will reduce the use of conventional insecticides by the public health authorities and help in reducing selection pressure of insecticides.

  9. Potential topical natural repellent against Ae. aegypti, Culex sp. and Anopheles sp. mosquitoes

    Directory of Open Access Journals (Sweden)

    Dewi Nur Hodijah

    2014-08-01

    Full Text Available AbstrakLatar belakang:Minyak atsiri daun sirih diketahui mempunyai daya proteksi. Dibuatkan losion berdasarkan pengantar sediaan farmasi yang ditambahkan minyak atsiri daun nilam. Sediaan losion dipilih agar dapat menempel lebih lama di permukaan kulit. Tujuan penelitian ini untuk membandingkan daya proteksi antara losion dengan penambahan minyak nilam dan losion tanpa penambahan minyak nilam dibandingkan daya proteksi dengan DEET. Metode: Penelitian ini merupakan penelitian eksperimental laboratorium. Semua nyamuk uji berasal dari insektarium laboratorium penelitian kesehatan Loka litbang P2B2 Ciamis. Konsentrasi minyak atsiri daun sirih dalam losion adalah 4%; konsentrasi minyak nilam sebagai zat pengikat adalah 0,4%. Formula yang digunakan yaitu formula dasar yang ada pada pengantar sediaan farmasi. Uji repelensi dilakukan dengan menggunakan metoda yang direkomendasikan oleh Komisi pestisida.Hasil: Dihasilkan formulasi losion yang stabil dan masih memenuhi standar formulasi sediaan. Berdasarkan hasil, diperoleh data bahwa DEET dan losion hasil modifikasi memiliki rata-rata daya proteksi di atas 90% selama 6 jam terhadap nyamuk Ae.aegypti dan Culex sp. Kesimpulan: Penambahan minyak nilam pada losion sirih dapat meningkatkan daya proteksi terhadap hinggapan nyamuk Ae. aegypti dan Culex sp. (Health Science Indones 2014;1:44-8Kata kunci:repelen alamiah, minyak atsiri, daun sirih, daun nilam, Ae. aegypti, Culex sp.AbstractBackground: Betel leaf essential oil lotion has been known to have insect repellent properties. A lotion was made based on a pharmaceutical formula from a monograph where patchouli leaf essential oil was added. A lotion preparation was intended to enhance adherence of the formula on the surface of the skin. The purpose of this study was to compare protection percentage of lotion with patchouli oil and without patchouli oil lotion compared to DEET.Methods: This study is an experimental laboratory-based research. All mosquitoes

  10. Genetic diversity and population genetics of mosquitoes (Diptera: Culicidae: Culex spp.) from the Sonoran Desert of North America.

    Science.gov (United States)

    Pfeiler, Edward; Flores-López, Carlos A; Mada-Vélez, Jesús Gerardo; Escalante-Verdugo, Juan; Markow, Therese A

    2013-01-01

    The population genetics and phylogenetic relationships of Culex mosquitoes inhabiting the Sonoran Desert region of North America were studied using mitochondrial DNA and microsatellite molecular markers. Phylogenetic analyses of mitochondrial cytochrome c oxidase subunit I (COI) from mosquitoes collected over a wide geographic area, including the Baja California peninsula, and mainland localities in southern Arizona, USA and Sonora, Mexico, showed several well-supported partitions corresponding to Cx. quinquefasciatus, Cx. tarsalis, and two unidentified species, Culex sp. 1 and sp. 2. Culex quinquefasciatus was found at all localities and was the most abundant species collected. Culex tarsalis was collected only at Tucson, Arizona and Guaymas, Sonora. The two unidentified species of Culex were most abundant at Navojoa in southern Sonora. Haplotype and nucleotide diversities in the COI gene segment were substantially lower in Cx. quinquefasciatus compared with the other three species. Analysis of molecular variance revealed little structure among seven populations of Cx. quinquefasciatus, whereas significant structure was found between the two populations of Cx. tarsalis. Evidence for an historical population expansion beginning in the Pleistocene was found for Cx. tarsalis. Possible explanations for the large differences in genetic diversity between Cx. quinquefasciatus and the other species of Culex are presented.

  11. Genetic Diversity and Population Genetics of Mosquitoes (Diptera: Culicidae: Culex spp. from the Sonoran Desert of North America

    Directory of Open Access Journals (Sweden)

    Edward Pfeiler

    2013-01-01

    Full Text Available The population genetics and phylogenetic relationships of Culex mosquitoes inhabiting the Sonoran Desert region of North America were studied using mitochondrial DNA and microsatellite molecular markers. Phylogenetic analyses of mitochondrial cytochrome c oxidase subunit I (COI from mosquitoes collected over a wide geographic area, including the Baja California peninsula, and mainland localities in southern Arizona, USA and Sonora, Mexico, showed several well-supported partitions corresponding to Cx. quinquefasciatus, Cx. tarsalis, and two unidentified species, Culex sp. 1 and sp. 2. Culex quinquefasciatus was found at all localities and was the most abundant species collected. Culex tarsalis was collected only at Tucson, Arizona and Guaymas, Sonora. The two unidentified species of Culex were most abundant at Navojoa in southern Sonora. Haplotype and nucleotide diversities in the COI gene segment were substantially lower in Cx. quinquefasciatus compared with the other three species. Analysis of molecular variance revealed little structure among seven populations of Cx. quinquefasciatus, whereas significant structure was found between the two populations of Cx. tarsalis. Evidence for an historical population expansion beginning in the Pleistocene was found for Cx. tarsalis. Possible explanations for the large differences in genetic diversity between Cx. quinquefasciatus and the other species of Culex are presented.

  12. Genetic Diversity and Population Genetics of Mosquitoes (Diptera: Culicidae: Culex spp.) from the Sonoran Desert of North America

    Science.gov (United States)

    Pfeiler, Edward; Flores-López, Carlos A.; Mada-Vélez, Jesús Gerardo; Escalante-Verdugo, Juan; Markow, Therese A.

    2013-01-01

    The population genetics and phylogenetic relationships of Culex mosquitoes inhabiting the Sonoran Desert region of North America were studied using mitochondrial DNA and microsatellite molecular markers. Phylogenetic analyses of mitochondrial cytochrome c oxidase subunit I (COI) from mosquitoes collected over a wide geographic area, including the Baja California peninsula, and mainland localities in southern Arizona, USA and Sonora, Mexico, showed several well-supported partitions corresponding to Cx. quinquefasciatus, Cx. tarsalis, and two unidentified species, Culex sp. 1 and sp. 2. Culex quinquefasciatus was found at all localities and was the most abundant species collected. Culex tarsalis was collected only at Tucson, Arizona and Guaymas, Sonora. The two unidentified species of Culex were most abundant at Navojoa in southern Sonora. Haplotype and nucleotide diversities in the COI gene segment were substantially lower in Cx. quinquefasciatus compared with the other three species. Analysis of molecular variance revealed little structure among seven populations of Cx. quinquefasciatus, whereas significant structure was found between the two populations of Cx. tarsalis. Evidence for an historical population expansion beginning in the Pleistocene was found for Cx. tarsalis. Possible explanations for the large differences in genetic diversity between Cx. quinquefasciatus and the other species of Culex are presented. PMID:24302868

  13. Phytochemical, Toxicological and Pharmacological Studies of ...

    African Journals Online (AJOL)

    Phytochemical, Toxicological and Pharmacological Studies of Asiasari Radix et ... three species of the genus Asarum: A. heterotropoides Fr. Schmidt var. mandshuricum (Maxim.) Kitag., ..... third-instar larvae of Culex pipiens pallens. Coquillett ...

  14. Intragenomic variation in the second internal transcribed spacer of the ribosomal DNA of species of the genera Culex and Lutzia (Diptera: Culicidae)

    OpenAIRE

    Fabiana Tavares Vesgueiro; Bruna Demari-Silva; Rosely dos Santos Malafronte; Maria Anice Mureb Sallum; Mauro Toledo Marrelli

    2011-01-01

    Culex is the largest genus of Culicini and includes vectors of several arboviruses and filarial worms. Many species of Culex are morphologically similar, which makes their identification difficult, particularly when using female specimens. To aid evolutionary studies and species distinction, molecular techniques are often used. Sequences of the second internal transcribed spacer (ITS2) of ribosomal DNA (rDNA) from 16 species of the genus Culex and one of Lutzia were used to assess their genom...

  15. Natural infection of Culex theileri (Diptera: Culicidae) with Dirofilaria immitis (Nematoda: Filarioidea) on Madeira Island, Portugal.

    Science.gov (United States)

    Santa-Ana, Marta; Khadem, Manhaz; Capela, Ruben

    2006-01-01

    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.

  16. Multiple mutations and mutation combinations in the sodium channel of permethrin resistant mosquitoes, Culex quinquefasciatus

    Science.gov (United States)

    Li, Ting; Zhang, Lee; Reid, William R.; Xu, Qiang; Dong, Ke; Liu, Nannan

    2012-10-01

    A previous study identified 3 nonsynonymous and 6 synonymous mutations in the entire mosquito sodium channel of Culex quinquefasciatus, the prevalence of which were strongly correlated with levels of resistance and increased dramatically following insecticide selection. However, it is unclear whether this is unique to this specific resistant population or is a common mechanism in field mosquito populations in response to insecticide pressure. The current study therefore further characterized these mutations and their combinations in other field and permethrin selected Culex mosquitoes, finding that the co-existence of all 9 mutations was indeed correlated with the high levels of permethrin resistance in mosquitoes. Comparison of mutation combinations revealed several common mutation combinations presented across different field and permethrin selected populations in response to high levels of insecticide resistance, demonstrating that the co-existence of multiple mutations is a common event in response to insecticide resistance across different Cx. quinquefasciatus mosquito populations.

  17. Repellency and toxicity of aromatic plant extracts against the mosquito Culex pipiens molestus (Diptera: Culicidae).

    Science.gov (United States)

    Traboulsi, Abdallah F; El-Haj, Samih; Tueni, Marie; Taoubi, Khalil; Nader, Natalie Abi; Mrad, Abir

    2005-06-01

    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.

  18. Repellent activity of herbal essential oils against Aedes aegypti (Linn. and Culex quinquefasciatus (Say.

    Directory of Open Access Journals (Sweden)

    Duangkamon Sritabutra

    2013-08-01

    Full Text Available Objective: To determine the mosquito repellent activity of herbal essential oils against female Aedes aegypti and Culex quinquefasciatus. Methods: On a volunteer’s forearm, 0.1 mL of each essential oil was applied to 3 cm伊10 cm of exposed skin. The protection time was recorded for 3 min after every 30 min. Results: Essential oil from clove oil in olive oil and in coconut oil gave the longest lasting period of 76.50 min and 96.00 min respectively against Aedes aegypti. The citronella grass oil in olive oil, citronella grass oil in coconut oil and lemongrass oil in coconut oil exhibited protection against Culex quinquefasciatus at 165.00, 105.00, and 112.50 min respectively. Conclusions: The results clearly indicated that clove, citronella and lemongrass oil were the most promising for repellency against mosquito species. These oils could be used to develop a new formulation to control mosquitoes.

  19. Culex nigripalpus: a natural vector of wild turkey malaria (Plasmodium hermani) in Florida.

    Science.gov (United States)

    Forrester, D J; Nayar, J K; Foster, G W

    1980-07-01

    Durking 1977 and 1978, more than 21,000 female mosquitoes of 15 species were live-trapped in south Florida where high numbers of wild turkeys (Meleagris gallopavo) are known to harbor malarial infections. By inoculation of mosquito extracts into uninfected domestic poults, the presence of sporozoites of Plasmodium hermani was demonstrated in Culex nigrapalpus. This mosquito, previously shown to be a competent experimental vector, is believed to be the primary natural vector of wild turkey malaria in Florida.

  20. Experimental investigation of the susceptibility of Italian Culex pipiens mosquitoes to Zika virus infection.

    Science.gov (United States)

    Boccolini, Daniela; Toma, Luciano; Di Luca, Marco; Severini, Francesco; Romi, R; Remoli, Maria Elena; Sabbatucci, Michela; Venturi, Giulietta; Rezza, Giovanni; Fortuna, Claudia

    2016-09-01

    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.

  1. Toxicities of Organophosphate and Carbamat Insecticide Against Culex quinquefasciatus Mosquito Larvae

    OpenAIRE

    Endang Puji Astuti; Yuneu Yuliasih; Titin Delia; Marliah Santi

    2009-01-01

    Culex quinquefasciatus mosquito is increasing problem of public health, being the vector responsible for West Nile Virus and Filariasis. Chlorpirifos (Organofosfat) and Metonil (Carbamat) were known to posses insecticide activity against insect. The study was aimed to examine effectiveness of Klorpirifos and Metonil as larvicide against C. quinquefasciatus larval. Chlorpirifos a significantly higher larvicidal activity against 3th-4th instar larvae of C. quinquefasciatus than Metonil. The lar...

  2. Larvicidal activity of Dregea volubilis and Bombax malabaricum leaf extracts against the filarial vector Culex quinquefasciatus

    Institute of Scientific and Technical Information of China (English)

    Emdad Hossain; Anjali Rawani; Goutam Chandra; Subhash C Mandal; Jayanta Kumar Gupta

    2011-01-01

    Objective: To analyze the larvicidal activity of two plant leaf powder and leaf-extracts, Dregea volubilis and Bombax malabaricum against Culex quinquefasciatus. Methods: The larvicidal bioassay was done for powdered leaves of Dregea volubilis and Bombax malabaricum individually and their methanol extracts against first-, second-, third-and fourth-instar larval forms of Culex quinquefasciatus. Mortality rate was recorded after 24, 48 and 72 h of post-exposure. LC50 and LC90 values were calculated at different time intervals for third instar larvae. Results:All the graded concentration (0.1%, 0.2%, 0.3%, 0.4%, 0.5%) of powdered leaves showed significant (P<0.05) larval mortality. The mortality rate was higher in 50 ppm doses of methanolic extracts of both the plants against Culex quinquefaciatus. The corresponding LC50 values were 56.97 ppm and 48.85 ppm, respectively after 24 h of exposure. There is no mortality of non-target organism such as Chironomous circumdatus, Oreochromis niloticus niloticus and Diplonichus annulatum within 72 h of post exposure to 0.1%, 0.2%, 0.3%crude powdered leaves and methanolic extracts of both the two individual plants under the laboratory condition. The results of preliminary qualitative phytochemical analysis of both the plants revealed the presence of many bioactive principles such as steroids, tannins, flavonoids, triterpenoids, saponins, etc. that may be responsible for their bio-control potentiality. Conclusions:The results have shown potential and eco-friendly use of both plant extracts against larva of Culex quinquefasciatus for the first time.

  3. Experimental investigation of the susceptibility of Italian Culex pipiens mosquitoes to Zika virus infection

    Science.gov (United States)

    Boccolini, Daniela; Toma, Luciano; Di Luca, Marco; Severini, Francesco; Romi, R; Remoli, Maria Elena; Sabbatucci, Michela; Venturi, Giulietta; Rezza, Giovanni; Fortuna, Claudia

    2016-01-01

    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. PMID:27605056

  4. Native Argentinean cyclopoids (Crustacea: Copepoda) as predators of Aedes aegypti and Culex pipiens (Diptera: Culicidae) mosquitoes

    OpenAIRE

    Tranchida, María C.; Micieli, María V.; Arnaldo Maciá; García, Juan J.

    2009-01-01

    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 ur...

  5. Native Argentinean cyclopoids (Crustacea: Copepoda) as predators of Aedes aegypti and Culex pipiens (Diptera: Culicidae) mosquitoes

    OpenAIRE

    C. Tranchida, María; V. Micieli, María; Maciá, Arnaldo; J. García, Juan

    2008-01-01

    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 ur...

  6. Comparison of Biological Attributes of Culex quinquefasciatus (Diptera: Culicidae) Populations from India

    OpenAIRE

    Gokhale, Mangesh D.; Mandar S Paingankar; Dhaigude, Sachin D.

    2013-01-01

    Understanding the population dynamics of mosquito populations through life table analysis and insecticide susceptibility is important to assess the likely impact of vector control strategies as well as to aid the design of novel interventions. Variation in the life tables and other biological data was compared for two populations of Culex quinquefasciatus Say 1823 from geographically isolated regions, Gorakhpur and Pune from India. Under a standardized rearing regime and constant laboratory c...

  7. [Experimental observation of toxic effect of Bacillus thuringiensis var. israelensis against Aedes, Culex and Anopheles larvae].

    Science.gov (United States)

    Li, Ju-Lin; Zhu, Guo-Ding; Zhou, Hua-Yun; Tang, Jian-Xia; Cao, Jun

    2014-02-01

    To evaluate the toxic effect of Bacillus thuringiensis var. israelensis (Bti) wettable powder against Aedes, Culex and Anopheles larvae. The biological assay was applied to test the lethal concentration of 50% (LC50) of Bti wettable powder against Aedes, Culex and Anopheles larvae. The LC50(s) of Bti wettable powder against Aedes albopictus, Culex pipiens pallens and Anopheles sinensis larvae were 0.104, 0.160 microg/ml and 0.324 microg/ml, respectively; its biological potencies against them were 0.125, 0.192 IU/ml and 0.389 IU/ml, respectively. The LC50(s) of continuous contact of Bti wettable powder with An. sinensis stage III larvae for 1, 2 d and 3 d were 0.324, 0.092 microg/ml and 0.032 microg/ml, respectively, and its biological potencies were 0.389, 0.110 IU/ml and 0.038 IU/ml, respectively. The LC50(s) of the bacteria against An. sinensis stage I , II, III, IV were 0.024, 0.137, 0.324 microg/ml and 0.450 microg/ml, respectively, and the biological potencies were 0.029, 0.164, 0.389 IU/ml and 0.540 IU/ml, respectively. Bti wettable powder has a good toxicity to Aedes, Culex and Anopheles larvae, especially for the latter two. It is better to apply the bacteria at the early stage of mosquito larvae.

  8. Functional response analysis of Anisops sardea (Hemiptera: Notonectidae) against Culex quinquefasciatus in laboratory condition

    OpenAIRE

    Rajendra Prasad Mondal; Anupam Ghosh; Subhasis Bandyopadhyay; Goutam Chandra

    2014-01-01

    Background & objectives: Culex quinquefasciatus is the principal vector of lymphatic filariasis (LF). Application of alternative vector control methodologies are aimed at reduction of mosquito breeding sites and biting activity through the use of biological control methods. In the present study, functional response of aquatic Hemipteran backswimmer, Anisops sardea was assessed against Cx. quinquefasciatus larvae in laboratory bioassay. Methods: The functional respons of A. sardea was ass...

  9. The Morphological Variations of Culex pipiens Larvae (Diptera: Culicidae in Yazd Province, Central Iran

    Directory of Open Access Journals (Sweden)

    H Dehghan

    2010-12-01

    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

  10. Contributions to the Mosquito Fauna of Southeast Asia - II. The Genus Culex in Thailand (Diptera: Culicidae)

    Science.gov (United States)

    1967-01-01

    Pui Doi Mountain, Chiang Mai, Thailand. Iyengar (1938) reported pallidothorax as a carrier of Wuchereria maluyi. Hu ( 1940 ) induced starved females to...Dyar and Knab 1914, Inset. Inscit. menst. 2: 58. Type species: Phalangomyiu debilis Dyar and Knab. Laiomyia Izquierdo 1916, Tesis. Col. Est. Puebla ...M. K. 1940 . HU, S. M. K. 1958. Culex pallidothorax Theobald as a carrier of Wuchereriu bancrofti Cobbold. Lingnan Sci. J. 19: 543-547. Progress

  11. MODELO BIOGEOGRÁFICO DE LOS MOSQUITOS CULEX SPP. (DIPTERA: CULICIDAE EN MÉXICO

    Directory of Open Access Journals (Sweden)

    Maria Torres Olave

    2015-12-01

    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.

  12. Occurrence of avian Plasmodium and West Nile virus in culex species in Wisconsin

    Science.gov (United States)

    Hughes, T.; Irwin, P.; Hofmeister, E.; Paskewitz, S.M.

    2010-01-01

    The occurrence of multiple pathogens in mosquitoes and birds could affect the dynamics of disease transmission. We collected adult Culex pipiens and Cx. restuans (Cx. pipiens/restuans hereafter) from sites in Wisconsin and tested them for West Nile virus (WNV) and for avian malaria (Plasmodium). Gravid Cx. pipiens/restuans were tested for WNV using a commercial immunoassay, the RAMP?? WNV test, and positive results were verified by reverse transcriptasepolymerase chain reaction. There were 2 WNV-positive pools of Cx. pipiens/restuans in 2006 and 1 in 2007. Using a bias-corrected maximum likelihood estimation, the WNV infection rate for Cx. pipiens/restuans was 5.48/1,000 mosquitoes in 2006 and 1.08/1,000 mosquitoes in 2007. Gravid Cx. pipiens or Cx. restuans were tested individually for avian Plasmodium by a restriction enzymebased assay. Twelve mosquitoes were positive for avian Plasmodium (10.0), 2 were positive for Haemoproteus, and 3 were positive for Leucocytozoon. There were 4 mixed infections, with mosquitoes positive for >1 of the hemosporidian parasites. This work documents a high rate of hemosporidian infection in Culex spp. and illustrates the potential for co-infections with other arboviruses in bird-feeding mosquitoes and their avian hosts. In addition, hemosporidian infection rates may be a useful tool for investigating the ecological dynamics of Culex/avian interactions. ?? 2010 by The American Mosquito Control Association, Inc.

  13. Evaluation of immature mosquitocidal properties of Xanthium strumarium Linn. plant extracts against Culex mosquitoes (Diptera: Culicidae

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    Kasim Roba

    2015-11-01

    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.

  14. EVALUATION OF EXTRACTS FROM BAMBOO FOR BIOLOGICAL ACTIVITY AGAINST CULEX PIPIENS PALLENS

    Institute of Scientific and Technical Information of China (English)

    Hai-qunCao; Yong-deYue; Zhen-huaPeng; Ri-maoHua; FengTang

    2004-01-01

    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.

  15. Trypanosoma culicavium sp. nov., an avian trypanosome transmitted by Culex mosquitoes.

    Science.gov (United States)

    Votýpka, Jan; Szabová, Jana; Rádrová, Jana; Zídková, Lenka; Svobodová, Milena

    2012-03-01

    A novel avian trypanosome, Trypanosoma culicavium sp. nov., isolated from Culex mosquitoes, is described on the basis of naturally and experimentally infected vectors and bird hosts, localization in the vector, morphological characters and molecular data. This study provides the first comprehensive description of a trypanosome species transmitted by mosquitoes, in which parasites form plugs and rosettes on the stomodeal valve. Trypanosomes occurred as long epimastigotes and short trypomastigotes in vectors and culture and as long trypomastigotes in birds. Transmission of parasites to bird hosts was achieved exclusively by ingestion of experimentally infected Culex mosquito females by canaries (Serinus canaria), but not by Japanese quails (Coturnix japonica), nor by the bite of infected vectors, nor by ingestion of parasites from laboratory cultures. Transmission experiments and the identity of isolates from collared flycatchers (Ficedula albicollis) and Culex mosquitoes suggests that the natural hosts of T. culicavium are insectivorous songbirds (Passeriformes). Phylogenetic analyses of small-subunit rRNA and glycosomal glyceraldehyde-3-phosphate dehydrogenase gene sequences demonstrated that T. culicavium sp. nov. is more related to Trypanosoma corvi than to other avian trypanosomes (e.g. Trypanosoma avium and Trypanosoma bennetti).

  16. Resistência a inseticidas organofosforados e carbamatos em população de Culex quinquefasciatus Organophosphorous and carbamate resistence in a population of Culex quinquefasciatus

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    José Eduardo Bracco

    1997-04-01

    Full Text Available Relata-se a ocorrência, na população de Culex quinquefasciatus, de resistência a pelo menos dois organofosforados e a um carbamato (malathion, fenitrothion e propoxur, respectivamente, mostrando a necessidade de haver programa de manejo de inseticidas. A suscetibilidade dessa população ao piretróide permetrina indica essa classe como de escolha numa eventual necessidade de substituição dos organofosforados.The population of Culex quinquefasciatus breeding in the Pinheiros River (S. Paulo, Brazil has been controlled with organophosphates since 1980. However, the biting has constituted a continual nuisance to the human population who live in the vicinity of the river. The occurrence of insecticide resistance to at least two organophosphates and one carbamate (malathion, fenitrothion and propoxur, respectively to this insect population is reported. The results show the need to develop an insecticide management program. The suscetibility to permethrin (pyretroid suggests the possibility of using this class of insecticide shoul the need for replacement of the insecticide in use arise.

  17. Larvicidal activity of Cyclamen (Myrsinaceae) extracts against the larvae of West Nile virus vector Culex pipiens L. (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Emre Oz; Samed Koc; Olcay Dinc Dusen; Ramazan Mammadov; Huseyin Cetin

    2013-01-01

    Objective: To evaluate the larvicidal activity of the tuber extracts isolated from two species of Cyclamen (Cyclamen mirabile Hildebr. and Cyclamen alpinum Dammann ex. Sprenger) against Culex pipiens L. (Diptera: Culicidae). Methods: Twenty young (first-second) or older (third-fourth) instars of the Culex pipiens were exposed to various concentrations (100 to 1 000 ppm) of the extracts. Mortality was recorded after 12-, 24-, 48-, 72- and 96-h of exposure. Results: We determined that the young larval stages were more susceptible to the extracts in comparison with the older larval stages. A comparison of LC50 and LC90 values has shown that Cyclamen mirabile was more active than Cyclamen alpinum. Conclusions: This study is the first to report on the larvicidal activity of the extracts of Cyclamen species against Culex pipiens. More studies are needed to isolate and identify the active components involved, their mode of action, and effects on other mosquito and pest species.

  18. Summary of the symposium Global Perspective on the Culex pipiens Complex in the 21st Century: The Interrelationship of Culex pipiens, quinquefasciatus, molestus and others.

    Science.gov (United States)

    Linthicum, Kenneth J

    2012-12-01

    A symposium on the mosquitoes in the Culex pipiens Complex (Pipiens Complex), including Cx. pipiens, Cx. quinquefasciatus, and Cx. molestus, invited 17 of the world's experts on this species Complex to explore the current state of knowledge on the systematic status, speciation, ecology, biology, vector competence, population genetics, endosymbionts, and role in disease transmission of these species in various parts of the world. A Foreword, Introduction, 14 full papers, 3 abstracts and this Summary are published in this special issue of the Journal of the American Mosquito Control Association. A summary of findings, overall conclusions, and research needs will be discussed in relation to mosquito control and interrupting disease transmission caused by these species.

  19. Larvicidal activity of green synthesized silver nanoparticles using bark aqueous extract of Ficus racemosa against Culex quinquefasciatus andCulex gelidus

    Institute of Scientific and Technical Information of China (English)

    Kanayairam Velayutham; Chinnadurai Siva; Abdul Abdul Rahuman; Govindasamy Rajakumar; Selvaraj Mohana Roopan; Gandhi Elango; Chinnaperumal Kamaraj; Sampath Marimuthu; Thirunavukkarasu Santhoshkumar; Moorthy Iyappan

    2013-01-01

    Objective:To investigate the larvicidal activity of synthesized silver nanoparticles (AgNPs) utilizing aqueous bark extract ofFicus racemosa (F. racemosa) was tested against fourth instar larvae of filariasis vector,Culex quinquefasciatus (Cx. quinquefasciatus) and japanese encephalitis vectors,Culex gelidus (Cx. gelidus).Methods:The synthesizedAgNPs was characterized byUV-vis spectrum,X-ray diffraction (XRD),Scanning electron microscopy (SEM) andFourier transform infrared (FTIR).The larvicidal activities were assessed for24 h against the larvae ofCx. quinquefasciatus andCx. gelidus with varying concentrations of aqueous bark extract ofF. racemosa and synthesizedAgNPs.LC50 andr2 values were calculated.Results:The maximum efficacy was observed in crude aqueous extract ofF. racemosa against the larvae of Cx. quinquefasciatus andCx. gelidus (LC50=67.72 and63.70 mg/L;r2=0.995 and0.985) and the synthesizedAgNPs (LC50=12.00 and11.21 mg/L;r2=0.997 and0.990), respectively.SynthesizedAg NPs showed theXRD peaks at2θ values of27.61,29.60,35.48,43.48 and79.68were identified as (210), (121), (220), (200) and (311) reflections, respectively.TheFTIR spectra ofAgNPs exhibited prominent peaks at3425,2878,1627 and1382 in the region500-3000 cm-1.The peaks correspond to the presence of a stretching vibration of (NH)C=O group.SEM analysis showed shape in cylindrical, uniform and rod with the average size of250.60 nm.Conclusions:The biosynthesis of silver nanoparticles using bark aqueous extract ofF. racemosa and its larvicidal activity against the larvae of disease spreading vectors.The maximum larvicidal efficacy was observed in the synthesizedAgNPs.

  20. PENGARUH RADIASI SINAR GAMMA Co-60 TERHADAP STERILITAS DAN PERKEMBANGAN EMBRIO CULEX QUINQUEFASCIATUS

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    Riyani Setiyaningsih

    2015-05-01

    Full Text Available AbstrakTeknik Serangga Mandul merupakan teknik pengendalian vektor yang ramah lingkungan dan spesifi target. Aplikasi Teknik Serangga Mandul dalam pengendalian Cx quinquefasciatus belum pernah dilakukan di Indonesia, sehingga perlu uji pendahuluan sebelum aplikasi ke alam. Penelitian bertujuanmenentukan dosis optimal iradiasi sinar gamma Co-60 yang dapat mensterilkan dan berpengaruh terhadap perkembangan embrio Culex quinquefasciatus. Pupa jantan diradiasi dengan sinar gamma pada dosis 50 Gy, 50 Gy, 60 Gy, dan 70 Gy. Radiasi di lakukan di BATAN Jakarta. Nyamuk jantan yang muncul dari pupa kemudian di kawinkan dengan betina normal. Hasil perkawinan diamati sterilitas telur dan perkembangan embrio. Hasil penelitian menunjukkan sinar gamma Co-60 dosis 40 Gy, 50 Gy, 60 Gy, dan 70 Gy menyebabkan sterilitas telur yang dihasilkan 20,919%, 48,995%, 89,48%, dan 100%.Perlakuan dosis 40 Gy menghasilkan telur steril dengan 29,39% mengandung embrio dan 70,66% tidak mengandung embrio. Perlakuan dosis 50 Gy menghasilkan telur steril dengan 16,71% mengandung embrio dan 86,56% tidak mengandung embrio. Perlakuan dosis 60 Gy 9,35% telur steril mengandungembrio dan 90,64% tidak mengandung embrio. Perlakukan dosis 70 Gy 100 % telur yang dihasilkan steril dan tidak mengandung embrio. Dosis optimal yang dapat mensterilkan dan berpengaruh terhadap perkembangan embrio Culex quinquefasciatus adalah dosis 70 Gy.Kata kunci : Teknik Serangga Mandul, Culex quinquefasciatus dan sterilitasAbstractSterile Insect Tecnique is a vector control techniques that are environmentally safe and specifi targets. SIT application in the control of Cx quinquefasciatus has never been done in Indonesia, so we need a preliminary test before application to the nature. The aim of the study are to determine the optimal dose of gamma Co-60 radiation to sterilize and effect develop of embrio Culex quinquefasciatus. Male pupae radiated with gamma rays at a dose of 50 Gy, 50 Gy, 60 Gy, and 70 Gy

  1. Larvicidal, oviposition, and ovicidal effects of Artemisia annua (Asterales: Asteraceae) against Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Cheah, Shao-Xiong; Tay, Jia-Wei; Chan, Lai-Keng; Jaal, Zairi

    2013-09-01

    This study focuses on the larvicidal, oviposition, and ovicidal effects of a crude extract of Artemisia annua against Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus. Dried cells of Artemisia annua from cell suspension cultures were extracted using hexane. The extract showed moderate larvicidal effects against mosquitoes. At 24-h post treatment, the LC50 values for Anopheles sinensis, Aedes aegypti, and Culex quinquefasciatus were recorded as 244.55, 276.14, and 374.99 ppm, respectively. The percentage mortality of larvae was directly proportional to the tested concentration. Anopheles sinensis was found to be the most susceptible species, whereas Culex quinquefasciatus was the most tolerant to the Artemisia annua extract. The results indicated that the Artemisia annua extract showed concentration-dependent oviposition deterrent activity and had a strong deterrent effect. At 500 ppm, the percentage effective repellency was more than 85% compared with the control group for all the species, with oviposition activity index values of -0.94, -0.95, and -0.78 for Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus, respectively. In the ovicidal assay, the percentage hatchability of eggs after treatment with 500 ppm of Artemisia annua extract was significantly lower than the control, with values of 48.84 ± 4.08, 38.42 ± 3.67, and 79.35 ± 2.09% for Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus, respectively. Artemisia annua was found to be more effective against Aedes aegypti and Anopheles sinensis compared with Culex quinquefasciatus. This study indicated that crude extract of A. annua could be a potential alternative for use in vector management programs.

  2. Identification of genes involved in pyrethroid-, propoxur-, and dichlorvos- insecticides resistance in the mosquitoes, Culex pipiens complex (Diptera: Culicidae).

    Science.gov (United States)

    Li, Chun-xiao; Guo, Xiao-xia; Zhang, Ying-mei; Dong, Yan-de; Xing, Dan; Yan, Ting; Wang, Gang; Zhang, Heng-duan; Zhao, Tong-yan

    2016-05-01

    Culex pipiens pallens and Cx. p. quinquefasciatus are important vectors of many diseases, such as West Nile fever and lymphatic filariasis. The widespread use of insecticides to control these disease vectors and other insect pests has led to insecticide resistance becoming common in these species. In this study, high throughout Illumina sequencing was used to identify hundreds of Cx. p. pallens and Cx. p. quinquefasciatus genes that were differentially expressed in response to insecticide exposure. The identification of these genes is a vital first step for more detailed investigation of the molecular mechanisms involved in insecticide resistance in Culex mosquitoes.

  3. Flight muscle-specific expression of act88F: GFP in transgenic Culex quinquefasciatus Say (Diptera: Culicidae).

    Science.gov (United States)

    Allen, Margaret L; Christensen, Bruce M

    2004-12-01

    A strategy to engineer a strain of Culex mosquitoes refractory to filarial transmission is described. A requirement for success of the strategy is identification of a flight muscle-specific promoter that functions in the mosquito. A GFP marker gene under the control of the promoter region of the Drosophila melanogaster act88F gene was inserted into the genome of Culex quinquefasciatus. Transformation was confirmed by Mendelian genetics. Hybridization of a genomic Southern blot to a radiolabeled probe verified that the entire donor plasmid integrated into the mosquito genome. GFP expression in the transgenic mosquitoes was restricted to the flight muscles.

  4. Current susceptibility status of Malaysian Culex quinquefasciatus (Diptera: Culicidae) against DDT, propoxur, malathion, and permethrin.

    Science.gov (United States)

    Low, V L; Chen, C D; Lee, H L; Lim, P E; Leong, C S; Sofian-Azirun, M

    2013-01-01

    A nationwide investigation was carried out to determine the current susceptibility status of Culex quinquefasciatus Say populations against four active ingredients representing four major insecticide classes: DDT, propoxur, malathion, and permethrin. Across 14 study sites, both larval and adult bioassays exhibited dissimilar trends in susceptibility. A correlation between propoxur and malathion resistance and between propoxur and permethrin resistance in larval bioassays was found. The results obtained from this study provide baseline information for vector control programs conducted by local authorities. The susceptibility status of this mosquito should be monitored from time to time to ensure the effectiveness of current vector control operations in Malaysia.

  5. Natural vertical transmission of ndumu virus in Culex pipiens (Diptera: Culicidae) mosquitoes collected as larvae.

    Science.gov (United States)

    Lutomiah, Joel; Ongus, Juliette; Linthicum, Kenneth J; Sang, Rosemary

    2014-09-01

    Ndumu virus (NDUV) is a member of the family Togaviridae and genus Alphavirus. In Kenya, the virus has been isolated from a range of mosquito species but has not been associated with human or animal morbidity. Little is know about the transmission dynamics or vertebrate reservoirs of this virus. NDUV was isolated from two pools of female Culex pipiens mosquitoes, IJR37 (n = 18) and IJR73 (n = 3), which were collected as larvae on 15 April 2013 from two dambos near the village of Marey, Ijara District, Garissa County, Kenya, and reared to adults and identified to species. These results represent the first field evidence of vertical transmission of NDUV among mosquitoes.

  6. Native Argentinean cyclopoids (Crustacea: Copepoda) as predators of Aedes aegypti and Culex pipiens (Diptera: Culicidae) mosquitoes.

    Science.gov (United States)

    Tranchida, María C; Micieli, María V; Maciá, Arnaldo; García, Juan J

    2009-12-01

    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 biological control agents for mosquitoes.

  7. Biological control of Culex (Culex saltanensis Dyar, (Diptera, Culicidae through Bacillus thuringiensis israelensis in laboratory and field conditions Controle biológico de Culex (Culex saltanensis Dyar, (Diptera, Culicidae através de Bacillus thuringiensis israelensis em condições de laboratório e campo

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    João A. C. Zequi

    2007-03-01

    Full Text Available Culex (Culex saltanensis Dyar, 1928 can become a problem in urban centers because they reproduce abundantly in ponds organically enriched. It is vector of the Plasmodium spp. and Crithidia ricadoi Sibajev et al. 1993. This research verifies the efficacy of Bacillus thuringiensis israelensis on C. saltanensis in two temperature situations, both in laboratory and field conditions. LC50 for C. saltanensis immatures fourth instar, was 0.154 ppm and the LC95 was 0.248 ppm an average temperature of 25.7ºC. When exposed at a constant temperature of 12±1ºC and a photoperiod of 14L:10D, had its susceptibity decreased in 1.50 times in reation to LC50, when compared to room temperature. B. thuringiensis israelensis is highly efficient in the control of this mosquito in natural environment with a high level of polluants using the concentration of 2 liters/hectare, with applications every 15 days.Culex (Culex saltanensis Dyar, 1928 pode se tornar um problema nos centros urbanos, porque reproduz abundantemente em lagoas de tratamento de efluentes. Esse mosquito é vetor de Plasmodium spp. e Crithidia ricadoi Sibajev et al. 1993. O objetivo dessa pesquisa foi verificar a eficácia de Bacillus thuringiensis israelensis sobre C. saltanensis em condições de temperatura no laboratório e campo. A CL50 para imaturos de quarto ínstar de C. saltanensis foi 0,154 ppm e a C19(5 foi 0,248 ppm em temperatura ambiente média de 25,7ºC. Quando o bioensaio foi conduzido à temperatura constante de 12±1ºC e fotoperíodo de 14L:10E, a suscetibilidade da larva diminui em 1,50 vezes em relação a CL50, quando comparado a temperatura ambiente. B. thuringiensis israelensis é eficiente no controle desse mosquito em seu ambiente natural com altos índices de matéria orgânica, usando 2 litros/hectare com aplicações a cada 15 dias.

  8. Effect of ivermectin on the larvae of Anopheles gambiae and Culex quinquefasciatus

    DEFF Research Database (Denmark)

    Derua, Yahya A.; Malongo, Bernard B.; Simonsen, Paul E.

    2016-01-01

    Background: Ivermectin is used extensively globally for treatment of helminthic and ectoparasitic infections in animals and humans. The effect of excreted ivermectin on non-target organisms in aquatic and terrestrial environments has been increasingly reported. Due to its low water solubility...... and adsorption to sediments, the ivermectin exposure-risk to aquatic organisms dwelling in different strata of water bodies varies. This study assessed the survival of larvae of Anopheles gambiae Giles and Culex quinquefasciatus Say, when exposed to low concentrations of ivermectin under laboratory conditions...

  9. Larvicidal Activity of Cassia occidentalis (Linn. against the Larvae of Bancroftian Filariasis Vector Mosquito Culex quinquefasciatus

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    Deepak Kumar

    2014-01-01

    Full Text Available Background & Objectives. The plan of this work was to study the larvicidal activity of Cassia occidentalis (Linn. against the larvae of Culex quinquefasciatus. These larvae are the most significant vectors. They transmit the parasites and pathogens which cause a deadly disease like filariasis, dengue, yellow fever, malaria, Japanese encephalitis, chikungunya, and so forth, which are considered harmful towards the population in tropic and subtropical regions. Methods. The preliminary laboratory trail was undertaken to determine the efficacy of petroleum ether and N-butanol extract of dried whole plant of Cassia occidentalis (Linn. belonging to the family Caesalpiniaceae at various concentrations against the late third instar larvae of Culex quinquefasciatus by following the WHO guidelines. Results. The results suggest that 100% mortality effect of petroleum ether and N-butanol extract of Cassia occidentalis (Linn. was observed at 200 and 300 ppm (parts per million. The results obviously showed use of plants in insect control as an alternative method for minimizing the noxious effect of some pesticide compounds on the environment. Thus the extract of Cassia occidentalis (Linn. is claimed as more selective and biodegradable agent. Conclusion. This study justified that plant Cassia occidentalis (Linn. has a realistic mortality result for larvae of filarial vector. This is safe to individual and communities against mosquitoes. It is a natural weapon for mosquito control.

  10. An impossible journey? The development of Plasmodium falciparum NF54 in Culex quinquefasciatus.

    Science.gov (United States)

    Knöckel, Julia; Molina-Cruz, Alvaro; Fischer, Elizabeth; Muratova, Olga; Haile, Ashley; Barillas-Mury, Carolina; Miller, Louis H

    2013-01-01

    Although Anopheles mosquitoes are the vectors for human Plasmodium spp., there are also other mosquito species-among them culicines (Culex spp., Aedes spp.)-present in malaria-endemic areas. Culicine mosquitoes transmit arboviruses and filarial worms to humans and are vectors for avian Plasmodium spp., but have never been observed to transmit human Plasmodium spp. When ingested by a culicine mosquito, parasites could either face an environment that does not allow development due to biologic incompatibility or be actively killed by the mosquito's immune system. In the latter case, the molecular mechanism of killing must be sufficiently powerful that Plasmodium is not able to overcome it. To investigate how human malaria parasites develop in culicine mosquitoes, we infected Culex quinquefasciatus with Plasmodium falciparum NF54 and monitored development of parasites in the blood bolus and midgut epithelium at different time points. Our results reveal that ookinetes develop in the midgut lumen of C. quinquefasciatus in slightly lower numbers than in Anopheles gambiae G3. After 30 hours, parasites have invaded the midgut and can be observed on the basal side of the midgut epithelium by confocal and transmission electron microscopy. Very few of the parasites in C. quinquefasciatus are alive, most of them are lysed. Eight days after the mosquito's blood meal, no oocysts can be found in C. quinquefasciatus. Our results suggest that the mosquito immune system could be involved in parasite killing early in development after ookinetes have crossed the midgut epithelium and come in contact with the mosquito hemolymph.

  11. Orientation of Culex mosquitoes to carbon dioxide-baited traps: flight manoeuvres and trapping efficiency.

    Science.gov (United States)

    Cooperband, M F; Cardé, R T

    2006-03-01

    Females of Culex quinquefasciatus Say and Culex tarsalis Coquillet (Diptera: Culicidae) in the host-seeking stage were released and video recorded in three dimensions in a large field wind tunnel as they flew to four kinds of CO2-baited mosquito traps. The trapping efficiency (number of mosquitoes approaching compared to the number caught) was determined for each trap type. The Encephalitis Virus Surveillance (EVS), Mosquito Magnet Freedom (MMF) and Mosquito Magnet Liberty (MML) traps captured only 13-16% of approaching Cx. quinquefasciatus females, whereas the Mosquito Magnet-X (MMX) trap captured 58%. Similar results were obtained for Cx. tarsalis. Orientation behaviour and flight parameters of mosquitoes approaching the four traps were compared. Mosquitoes spent the most time orienting to the EVS trap. Flight speed decreased as mosquitoes entered the vicinity of each trap and a large portion of their time was spent within 30 cm downwind of the traps. Flights became highly tortuous downwind of the poorly performing traps and just upwind of the MMX trap. Differences between traps and possible explanations for the superior performance of the MMX trap are considered.

  12. Enzymatic characterization of insecticide resistance mechanisms in field populations of Malaysian Culex quinquefasciatus say (Diptera: Culicidae.

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    Van Lun Low

    Full Text Available BACKGROUND: There has been no comprehensive study on biochemical characterization of insecticide resistance mechanisms in field populations of Malaysian Culex quinquefasciatus. To fill this void in the literature, a nationwide investigation was performed to quantify the enzyme activities, thereby attempting to characterize the potential resistance mechanisms in Cx. quinquefasciatus in residential areas in Malaysia. METHODOLOGY/PRINCIPAL FINDINGS: Culex quinquefasciatus from 14 residential areas across 13 states and one federal territory were subjected to esterases, mixed function oxidases, glutathione-S-transferase and insensitive acetylcholinesterase assays. Enzyme assays revealed that α-esterases and β-esterases were elevated in 13 populations and 12 populations, respectively. Nine populations demonstrated elevated levels of mixed function oxidases and glutathione-S-transferase. Acetylcholinesterase was insensitive to propoxur in all 14 populations. Activity of α-esterases associated with malathion resistance was found in the present study. In addition, an association between the activity of α-esterases and β-esterases was also demonstrated. CONCLUSIONS/SIGNIFICANCE: The present study has characterized the potential biochemical mechanisms in contributing towards insecticide resistance in Cx. quinquefasciatus field populations in Malaysia. Identification of mechanisms underlying the insecticide resistance will be beneficial in developing effective mosquito control programs in Malaysia.

  13. The Culex pipiens complex in the Mississippi River basin: identification, distribution, and bloodmeal hosts.

    Science.gov (United States)

    Savage, Harry M; Kothera, Linda

    2012-12-01

    Members of the Culex pipiens complex are the primary vectors of St. Louis encephalitis virus and West Nile virus in the Mississippi River basin (MRB). The Cx. pipiens complex in the MRB is composed of 4 taxa: Cx. p. pipiens form pipiens, Cx. p. quinquefasciatus, hybrids between Cx. p. pipiens f. pipiens and Cx. p. quinquefasciatus, and Cx. p. pipiens form molestus. Three studies on bloodmeal hosts with large sample sizes have been conducted on members of the Cx. pipiens complex in the MRB including 1 each on Cx. p. quinquefasciatus from Louisiana, Cx. p. pipiens-quinquefasciatus hybrids from Tennessee, and Cx. p. pipiens from Illinois. The top 8 bloodmeal hosts from each of the 3 sites accounted for 68-92% of bloodmeals. Only 14 species accounted for the top 8 bloodmeal hosts at each of the 3 sites. The most often utilized bloodmeal hosts for members of the Culex pipiens complex within the MRB are the American robin, Northern cardinal, human, raccoon, common grackle, house sparrow, mourning dove, dog, Northern mockingbird, blue jay, opossum, domestic horse, house finch and European starling. Human feeding varied widely among sites from 1% to 15.7% of bloodmeals. The proportion of bloodmeals taken on humans is an important epidemiological variable and future studies are needed to define the primary genetic and environmental factors that influence host utilization by members of the Cx. pipiens complex.

  14. Larval Habitat Characteristics of Mosquitoes of the Genus Culex (Diptera: Culicidae in Guilan Province, Iran

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    S Azari-Hamidian

    2007-05-01

    Full Text Available An investigation was carried out during April to December 2000 to study mosquito fauna and ecology in Guilan Prov¬ince of northern Iran. The mosquito larvae were collected by dipping method and larval habitat characteristics recorded ac¬cording to hydro-ecological features. In total, 3937 larvae of the genus Culex from 92 larval breeding sites were collected. Six spe¬cies of the genus Culex; Cx. mimeticus, Cx. pipiens, Cx. theileri, Cx. tritaeniorhynchus, Cx. hortensis, and Cx. terri¬tans were identified in the province and respectively comprised 10.3%, 47.2%, 2.2%, 31%, 6.5%, and 2.8% of the samples. Most of the larvae were collected from the natural habitats (75.6% such as river edges (6.5%, riverbed pools (28.2%, rain pools (47.8%, stream edges (9.4%, grasslands (1.9%, marshes (2.8%, and hoof-prints (3.4% and others from artificial habitats (24.4% including rice fields (32.1%, irrigation channels (7.1%, wells (16.4%, discarded concrete tubes (33.1%, dis¬carded tires (11.0%, and agricultural water-storage pools (0.3%. The ecology of Cx. pipiens and Cx. tritaeniorhynchus, which are the most prevalent species and potentially involved in the transmission of many pathogens to humans and domes¬ticated animals, must be extensively studied.

  15. RNA Splicing in a New Rhabdovirus from Culex Mosquitoes▿†

    Science.gov (United States)

    Kuwata, Ryusei; Isawa, Haruhiko; Hoshino, Keita; Tsuda, Yoshio; Yanase, Tohru; Sasaki, Toshinori; Kobayashi, Mutsuo; Sawabe, Kyoko

    2011-01-01

    Among members of the order Mononegavirales, RNA splicing events have been found only in the family Bornaviridae. Here, we report that a new rhabdovirus isolated from the mosquito Culex tritaeniorhynchus replicates in the nuclei of infected cells and requires RNA splicing for viral mRNA maturation. The virus, designated Culex tritaeniorhynchus rhabdovirus (CTRV), shares a similar genome organization with other rhabdoviruses, except for the presence of a putative intron in the coding region for the L protein. Molecular phylogenetic studies indicated that CTRV belongs to the family Rhabdoviridae, but it is yet to be assigned a genus. Electron microscopic analysis revealed that the CTRV virion is extremely elongated, unlike virions of rhabdoviruses, which are generally bullet shaped. Northern hybridization confirmed that a large transcript (approximately 6,500 nucleotides [nt]) from the CTRV L gene was present in the infected cells. Strand-specific reverse transcription-PCR (RT-PCR) analyses identified the intron-exon boundaries and the 76-nt intron sequence, which contains the typical motif for eukaryotic spliceosomal intron-splice donor/acceptor sites (GU-AG), a predicted branch point, and a polypyrimidine tract. In situ hybridization exhibited that viral RNAs are primarily localized in the nucleus of infected cells, indicating that CTRV replicates in the nucleus and is allowed to utilize the host's nuclear splicing machinery. This is the first report of RNA splicing among the members of the family Rhabdoviridae. PMID:21507977

  16. Detection and isolation of the α-proteobacterium Asaia in Culex mosquitoes.

    Science.gov (United States)

    De Freece, C; Damiani, C; Valzano, M; D'Amelio, S; Cappelli, A; Ricci, I; Favia, G

    2014-12-01

    Investigations of microbiota within mosquitoes continue to widen the spectrum of possible symbiont-based applications against vector-borne diseases. In this context, α-proteobacteria of the genus Asaia (Rhodospirillales: Acetobacteraceae) are emerging as possible endosymbiotic candidates, particularly in paratransgenic approaches aimed at interrupting pathogen transmission. Previous studies have shown that Asaia spp. distribution among Anopheles gambiae and Anopheles stephensi (Diptera: Culicidae) mosquitoes displayed positive rates of infection in isolated midguts, salivary glands and reproductive tissues. Similarly, Asaia has been detected in Aedes albopictus (Stegomyia albopicta) and Aedes aegypti (Stegomyia aegypti) (Diptera: Culicidae) populations. Within the Culex pipiens complex (Diptera: Culicidae), Asaia infection is still largely unexplored. Here, we summarize a preliminary survey of laboratory-reared Cx. pipiens complex and field-collected Culex quinquefasciatus for the presence of Asaia spp., and present the first identification of Asaia in some of the members of the Cx. pipiens complex and the first description in West African populations of Cx. quinquefasciatus. © 2013 The Royal Entomological Society.

  17. A Pictorial Key for Culex pipiens Complex (Diptera: Culicidae In Iran

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    Hossein Dehghan

    2016-01-01

    Full Text Available Background: The aim of this study was to design pictorial key and taxonomic literature of Culex pipiens complex in Iran.Methods: Larvae were collected using standard dipping methods in 13 randomly selected areas of Bushehr, Hame­dan, Kerman, Khorasan-e-Razavi, Khuzistan, Mazandaran, Tehran, Sistan and Baluchistan and Yazd Provinces from April 2009 to October 2010. The data were analyzed using SPSS Ver. 11.5.Results: Culex pipiens larvae were identified based on the Seta 1 of the abdominal segments III–IV in north and central parts of Iran. This diagnostic character had some variation among the Cx. quinquefasciatus collected from south of the country. The identification value of intersection of costa, subcosta and bifurcation of R2+3 of female veins, was calculated as 90–100 % for Cx. pipiens. This diagnostic character was varied among the Cx. quinquefas­ciatus specimens. The male genitalia found as the main characters to distinguish of Cx. quinquefasciatus from Cx. pipiens.Conclusion: It is necessary more studies on the behavior and genetic variations of Cx. pipiens complex in Iran.

  18. Culex saltanensis Dyar, 1928: natural vector of Plasmodium juxtanucleare in Rio de Janeiro, Brazil

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    Ricardo Lourenço-de-Oliveira

    1991-03-01

    Full Text Available Searching for the natural vector of Plasmodium juxtanucleare in an enzootic locality: Granjas Calábria (33% of the chickens infected, Jacarepaguá, in Rio de Janeiro, Brazil, 13 comparative captures of mosquitoes were carried out, simultaneously on man (out-doors and on chiken (in a poultry-yard, between 6 and 9 p.m., from September to March 1989. Culex saltanensis was the most frequent species in captures on chicken, accounting for 41.7% of the mosquitoes collected on this bait, showing to be highly ornithophilic (90% captured on chicken versus 10% on man. Seven specimens of Cx. saltanensis were found naturally infected in granjas Calábria: five with mature pedunculate oocysts and two with sporozoites (on in the haemocoele and one in the salivary glands. These sporozoites porudced an infection by P. juxtanucleare in a chick, which had parasitemia on day 41 after inoculation. One Cx. coronator was found with mature pedunculate oocysts. Culex saltanensis was regarded as primary vector of P. juxtanucleare in Rio de Janeiro for being highly ornithophilic and in enough density to maintain the transmission, having been found with infective sporozoites in its salivary glands, and being susceptible to the parasite and able to transmit experimentally it by the bite.

  19. Larvicidal Activity of Cassia occidentalis (Linn.) against the Larvae of Bancroftian Filariasis Vector Mosquito Culex quinquefasciatus

    Science.gov (United States)

    Kumar, Deepak; Chawla, Rakesh; Dhamodaram, P.; Balakrishnan, N.

    2014-01-01

    Background & Objectives. The plan of this work was to study the larvicidal activity of Cassia occidentalis (Linn.) against the larvae of Culex quinquefasciatus. These larvae are the most significant vectors. They transmit the parasites and pathogens which cause a deadly disease like filariasis, dengue, yellow fever, malaria, Japanese encephalitis, chikungunya, and so forth, which are considered harmful towards the population in tropic and subtropical regions. Methods. The preliminary laboratory trail was undertaken to determine the efficacy of petroleum ether and N-butanol extract of dried whole plant of Cassia occidentalis (Linn.) belonging to the family Caesalpiniaceae at various concentrations against the late third instar larvae of Culex quinquefasciatus by following the WHO guidelines. Results. The results suggest that 100% mortality effect of petroleum ether and N-butanol extract of Cassia occidentalis (Linn.) was observed at 200 and 300 ppm (parts per million). The results obviously showed use of plants in insect control as an alternative method for minimizing the noxious effect of some pesticide compounds on the environment. Thus the extract of Cassia occidentalis (Linn.) is claimed as more selective and biodegradable agent. Conclusion. This study justified that plant Cassia occidentalis (Linn.) has a realistic mortality result for larvae of filarial vector. This is safe to individual and communities against mosquitoes. It is a natural weapon for mosquito control. PMID:24688786

  20. The morphological variations of Culex pipiens (Diptera:Culicidae) in central Iran

    Institute of Scientific and Technical Information of China (English)

    Hossein Dehghan; Javid Sadraei; Seyed Hassan Moosa-Kazemi

    2011-01-01

    Objective:To determine the variations in morphological characters of Culex pipiens complex and identify the species complex. Methods:A study was carried out from April to October 2009 in Yazd Province, Iran. This study was performed in two randomly selected rural villages in Yazd County using different sampling methods such as larval collection, hand catch, pyrethrum space spray, light trap, and pit shelter collections. The data were analyzed using SPSS software Ver. 16. ANOVA and Tukey's post-hoc test was used to compare the ratios of the samples. Results:The average of the DV/D ration was 0.090±0.007 and the range was 0-0.33. The average D/V ratio was 1.07±0.02, with maximum 1.6 and minimum 0.6. The costa and subcosta intersection were observed beyond the bifurcation of R2+3 in most of the specimens. The bifurcations of R2+3 and M1+3 veins were not on one direction in all samples. The range of the R-Cell/R2+3 ratio was 2.42-7.91. The average ratio of cross wing was 2.25±0.04 with a range of 1.36-3.70. Conclusions: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.

  1. Wolbachia infection and mitochondrial DNA comparisons among Culex mosquitoes in South West Iran.

    Science.gov (United States)

    Behbahani, A

    2012-01-01

    The control of mosquito borne diseases needs new methods given widespread insecticide resistance in many mosquito species. The inherited endosymbiont Wolbachia, found in many arthropods, provides a biological system to reduce the transmission of these diseases and replace the population of vectors with non-vectors using cytoplasmic incompatibility. The aim of this study was to understand the rate of Wolbachia infection among Culex species in the region and to see the effect of Wolbachia infection on mitochondrial genome. In this study three species of Culex mosquitoes were collected from Shoushtar in south west of Iran and examined for Wolbachia infection by Polymerase Chain Reaction (PCR). All of the C. quinquefasciatus specimens were infected with Wolbachia, while C. tritaeniorynchus and C. theileri showed no infection with Wolbachia. The 340 bp of AT rich of mtDNA was sequenced from 30 individuals, 10 individuals of each species. Three sequence haplotypes were found in C. tritaeniorynchus and C. theileri while there was only one haplotype in C. quinquefasciatus. The reduction of haplotypes diversity may be result of a sweep of Wolbachia in this species.

  2. Evaluation of oviposition substrates and organic infusions on collection of Culex in Florida.

    Science.gov (United States)

    Allan, Sandra A; Bernier, Ulrich R; Kline, Daniel L

    2005-09-01

    Gravid mosquito traps are commonly used for both arbovirus surveillance and population surveillance of mosquitoes of the genus Culex. Oviposition substrates, used as baits in these traps, were tested against Culex under laboratory and field conditions. In the laboratory all substrates tested as 1% and 10% dilutions in 2-choice bioassays against female Cx. quinquefasciatus were significantly more effective than well water controls in eliciting oviposition. Strongest responses were to dilutions of dairy effluent, followed by larval water and infusions of alfalfa hay, alfalfa pellets, Bermuda hay, oak leaves, and Typha leaves, with lowest responses to cow manure infusion. In the field, few significant differences in collections were obtained between traps baited with different infusions. Significantly more Cx. quinquefasciatus and Cx. nigripalpus were collected in traps baited with cow manure infusion (highest) compared to alfalfa hay infusion (lowest). Responses of Cx. quinquefasciatus to dairy effluent and infusions of Bermuda hay, oak leaves, and Typha leaves were not significantly different from either cow manure infusion or alfalfa hay infusion. Responses of Cx. nigripalpus were highest to cow manure infusion and equally low to infusions of alfalfa hay and Typha leaves; moderate responses were observed to dairy effluent and infusions of Bermuda hay and oak leaves. Gravid females comprised 66.7-81.9% of the collections for each infusion type, with no significant difference among infusions in the proportion of gravid females collected.

  3. Diversity of Culex torrentium Martini, 1925 - a potential vector of arboviruses and filaria in Europe.

    Science.gov (United States)

    Werblow, Antje; Bolius, Sarah; Dorresteijn, Adriaan W C; Melaun, Christian; Klimpel, Sven

    2013-07-01

    Culex torrentium is one of the most common mosquito species in Germany. Due to its sympatric occurrence as well as its similar morphological and ecological characteristics, it has often been confused with another common species, Culex pipiens. Both species are known to be potential vectors for different arboviruses (not only in Germany) with C. torrentium being a possible vector for Sindbis or Ockelbo virus. In our study, we analyzed the genetic variability in a 658 bp fragment of the cytochrome c oxidase subunit I gene (coxI) of C. torrentium, from nine localities in the Frankfurt/Rhine-Main Metropolitan Region. The results of our genetic survey indicate a higher genetic diversity in this gene region for C. torrentium than for the morphologically similar C. pipiens. Our findings may explain the difficulties in the past to find morphological characteristics that apply to all populations of C. torrentium, when attempting to separate them clearly from C. pipiens, by any other criteria than male genitalia. Being ornithophilic, possible hybrids between C. torrentium and the humanophilic C. pipiens biotype molestus, could potentially serve as important vectors for zoonotic diseases. Therefore, we recommend that greater emphasis is placed on the ecological characteristics, population structure, and the taxonomy of this often neglected species, in the future.

  4. Evaluation of released malathion and spinosad from chitosan/alginate/gelatin capsules against Culex pipiens larvae

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    Badawy MEI

    2016-09-01

    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

  5. Laboratory and field evaluation of spinosad formulation Natular T30 against immature Culex mosquitoes (Diptera: Culicidae).

    Science.gov (United States)

    Su, Tianyun; Cheng, Min-Lee; Thieme, Jennifer

    2014-07-01

    Spinosad consisting of spinosyn A and D is derived from a naturally occurring, soil-dwelling bacterium, Saccharopolyspora spinosa. Spinosyns are neurotoxins that activate postsynaptic nicotinic acetylcholine and gamma-aminobutyric acid receptors and cause rapid excitation of the insect nervous system and ultimately exhaustion and death of the targets. During the past 30 yr, numerous spinosad-based formulations have been developed and applied to control various arthropod pests of agricultural importance. Natular T-30 is a new slow-release formulation containing 8.33% spinosad for use in mosquito larval control programs. High-level larvicidal activity, as indicated by low LC50 and LC90 levels, was demonstrated against Culex quinquefasciatus Say in the laboratory. Larvicidal efficacy was evaluated in semifield microcosms, field mesocosms, and underground storm drains. Fair performance against larval populations of Culex spp. and other mosquito species was achieved, although low efficacy during the initial few days posttreatment was encountered. This slow-release formulation will play an important role in controlling mosquitoes in persistent breeding sources.

  6. An insight into the sialotranscriptome of the West Nile mosquito vector, Culex tarsalis

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    Olson Kenneth E

    2010-01-01

    Full Text Available Abstract Background Saliva of adult female mosquitoes help sugar and blood feeding by providing enzymes and polypeptides that help sugar digestion, control microbial growth and counteract their vertebrate host hemostasis and inflammation. Mosquito saliva also potentiates the transmission of vector borne pathogens, including arboviruses. Culex tarsalis is a bird feeding mosquito vector of West Nile Virus closely related to C. quinquefasciatus, a mosquito relatively recently adapted to feed on humans, and the only mosquito of the genus Culex to have its sialotranscriptome so far described. Results A total of 1,753 clones randomly selected from an adult female C. tarsalis salivary glands (SG cDNA library were sequenced and used to assemble a database that yielded 809 clusters of related sequences, 675 of which were singletons. Primer extension experiments were performed in selected clones to further extend sequence coverage, allowing for the identification of 283 protein sequences, 80 of which code for putative secreted proteins. Conclusion Comparison of the C. tarsalis sialotranscriptome with that of C. quinquefasciatus reveals accelerated evolution of salivary proteins as compared to housekeeping proteins. The average amino acid identity among salivary proteins is 70.1%, while that for housekeeping proteins is 91.2% (P Aedes genus have been identified in C. tarsalis. Interestingly, a protein family so far unique to C. quinquefasciatus, with 30 genes, is also found in C. tarsalis, indicating it was not a specific C. quinquefasciatus acquisition in its evolution to optimize mammal blood feeding.

  7. Wolbachia induces male-specific mortality in the mosquito Culex pipiens (LIN strain.

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    Jason L Rasgon

    Full Text Available BACKGROUND: Wolbachia are maternally inherited endosymbionts that infect a diverse range of invertebrates, including insects, arachnids, crustaceans and filarial nematodes. Wolbachia are responsible for causing diverse reproductive alterations in their invertebrate hosts that maximize their transmission to the next generation. Evolutionary theory suggests that due to maternal inheritance, Wolbachia should evolve toward mutualism in infected females, but strict maternal inheritance means there is no corresponding force to select for Wolbachia strains that are mutualistic in males. METHODOLOGY/PRINCIPAL FINDINGS: Using cohort life-table analysis, we demonstrate that in the mosquito Culex pipiens (LIN strain, Wolbachia-infected females show no fitness costs due to infection. However, Wolbachia induces up to a 30% reduction in male lifespan. CONCLUSIONS/SIGNIFICANCE: These results indicate that the Wolbachia infection of the Culex pipiens LIN strain is virulent in a sex-specific manner. Under laboratory situations where mosquitoes generally mate at young ages, Wolbachia strains that reduce male survival could evolve by drift because increased mortality in older males is not a significant selective force.

  8. Sampling gravid Culex quinquefasciatus (Diptera: Culicidae) in Tanzania with traps baited with synthetic oviposition pheromone and grass infusions

    NARCIS (Netherlands)

    Mboera, L.E.G.; Takken, W.; Mdira, K.Y.; Pickett, J.A.

    2000-01-01

    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 s

  9. Variation in the number and position of siphonal setae in Culex quinquefasciatus from Key West and Vero Beach, Florida, USA.

    Science.gov (United States)

    Rey, Jorge R; O'Meara, George F; O'Oonnell, Sheila M; Darsie, Richard F

    2006-09-01

    Variations in diagnostic siphonal characters of Culex quinquefasciatus larvae collected in Key West and Vero Beach, FL, are described. We observed specimens with 3, 4, and 5 sets of siphonal setae and also observed frequent variation in the insertion point of the proximal and subapical setae.

  10. Efficacy of a Mosaic Long-Lasting Insecticide Net, PermaNet 3.0, against Wild Populations of Culex quinquefasciatus in Experimental Huts in Togo

    OpenAIRE

    Dery, Dominic B; Ketoh, Guillaume K.; Chabi, Joseph; Apetogbo, George; Glitho, Isabelle A.; Baldet, Thierry; Hougard, Jean-Marc

    2013-01-01

    PermaNet 3.0 was evaluated against Culex quinquefasciatus in experimental huts in Lomé. Endpoints were deterrence, exophily, blood feeding inhibition, and mortality. Insecticide susceptibility of Culex quinquefasciatus was assessed with permethrin (1%), DDT (4%), bendiocarb (0.1%), deltamethrin (0.5%, 0.05%), carbosulfan (0.4%), and chlorpyrifos methyl (0.4%). Total of 1,223 Cx. quinquefasciatus females were collected. PermaNet 3.0 unwashed deterred 16.84% Culex mosquitoes. After 20 washes, i...

  11. Controle de Aedes (Stegomyia aegypti (Linnaeus, 1762 e Culex (Culex quinquefasciatus Say, 1823 através de formulados contendo Bacillus thuringiensis israelensis em temperaturas controladas

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    João Zequi

    2011-11-01

    Abstract. Aedes (Stegomyia aegypti (Linnaeus and Culex (Culex quinquefasciatus Say are important pathogen vectors in urban environments. This study was designed to evaluate commercial formulations containing Bacillus thuringiensis israelensis de Barjac for the control of Ae. aegypti and Cx. quinquefasciatus and to assess their efficiency as compared to manufacturers´ claims. The tested products were the liquid formulation of Aquabac® XT 1200 ITU/mg, Teknar® 3000AAU/mg, and Vectobac® AS 1200 ITU/mg, and the solid products Vectobac® WDG 3000 ITU/mg, Vectobac® Tablet 2200 ITU/mg, and the trial formulation of Biouel 500 ITU/mg. All products were tested at 25±2°C temperature and the liquid formulations were also tested at 15±2°C, 35±2°C, and at room temperature (25.37 to 28.73ºC. The experiments were conducted with 25 larvae at the early 4th stage, in 150 mL of distilled water; the dead larvae were counted 24 hours after product application. Results were analyzed using Probit to calculate CL50. The 25±2°C temperature, Vectobac WDG, and Vectobac Tablet were the most efficient in controlling Ae. aegypti, with CL50 of 0.10 (0.08 – 0.11 mg/L and 0.10 (0.09 – 0.11 mg/L, respectively. The most efficient products for Cx. quinquefasciatus were Vectobac WDG, Vectobac AS, Biouel, and Vectobac T. When the potency claimed by manufacturers was compared to our laboratory results, Biouel had the best performance for both species. Vectobac AS was the most efficient for both species of Culicidae tested at 15±2°C, 35±2°C and at room temperature (25.37 to 28.37°C. Lower product concentrations were required at 35±2°C room temperature to control Cx. quinquefasciatus than for Ae. aegypti.

  12. Mosquitocidal activity of Polygala arvensis Willd against Aedes aegypti (Linn., Anopheles stephensi (Liston. and Culex quinquefasciatus (Say. (Diptera: Culicidae

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    M. Deepa

    2014-12-01

    Full Text Available To determine the larvicidal, ovicidal and repellent activities of benzene and methanol extract of Polygala arvensis against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus Twenty five 3rd instar larvae of selected mosquitoes species were exposed to various concentrations (60-300 ppm and were assayed in the laboratory by using the protocol of WHO 2005; the 24 h LC50 values of the P. Arvensis leaf extract was determined following Probit analysis. The ovicidal activity was determined against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus exposed to variousconcentrations were tested under laboratory conditions and the hatch rates were assessed 120hrs post treatment. The repellent efficacy was determined against selected mosquitoes at three concentrations viz., 1.0, 2.0 and 3.0 mg/cm2 under the laboratory conditions. The LC50 and LC90 values of benzene and methanol extract of P. arvensis against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus larvae in 24 h were 75.32, 88.26, 82.46, 58.21, 46.37, 42.68 and 260.48, 275.26, 251.39, 208.45, 189.82 and 130.44 ppm, respectively. It has been noticed that the higher concentrations of P. arvensis extractspossesses strong ovicidal activity at 200 ppm concentration against Ae. aegypti, An. stephensi and C. quinquefasciatus, no egg hatchability was recorded. In the same way, methanol extracts showed maximum ovicidal activity followed by benzene extract against selected vector mosquitoes. In repellent activity, among two extracts tested P. arvensis methanol extract had strong repellent action against selected mosquitoes as it provided 100% protection against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus for 280min. From the results it can be concluded the P. arvensis extract was an excellent potential for controlling Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus mosquitoes.

  13. Genetic diversity of Wolbachia endosymbionts in Culex quinquefasciatus from Hawai`i, Midway Atoll, and Samoa

    Science.gov (United States)

    Atkinson, Carter T.; Watcher-Weatherwax, William; Lapointe, Dennis

    2016-01-01

    Incompatible insect techniques are potential methods for controlling Culex quinquefasciatus and avian disease transmission in Hawai‘i without the use of pesticides or genetically modified organisms. The approach is based on naturally occurring sperm-egg incompatibilities within the Culex pipiens complex that are controlled by different strains of the bacterial endosymbiont Wolbachia pipientis (wPip). Incompatibilities can be unidirectional (crosses between males infected with strain A and females infected with strain B are fertile, while reciprocal crosses are not) or bidirectional (reciprocal crosses between sexes with different wPip strains are infertile). The technique depends on release of sufficient numbers of male mosquitoes infected with an incompatible wPip strain to suppress mosquito populations and reduce transmission of introduced avian malaria (Plasmodium relictum) and Avipoxvirus in native forest bird habitats. Both diseases are difficult to manage using more traditional methods based on removal and treatment of larval habitats and coordination of multiple approaches may be needed to control this vector. We characterized the diversity of Wolbachia strains in C. quinquefasciatus from Hawai‘i, Kaua‘i, Midway Atoll, and American Samoa with a variety of genetic markers to identify compatibility groups and their distribution within and between islands. We confirmed the presence of wPip with multilocus sequence typing, tested for local genetic variability using 16 WO prophage genes, and identified similarities to strains from other parts of the world with a transposable element (tr1). We also tested for genetic differences in ankyrin motifs (ank2 and pk1) which have been used to classify wPip strains into five worldwide groups (wPip1–wPip5) that vary in compatibility with each other based on experimental crosses. We found a mixture of both widely distributed and site specific genotypes based on presence or absence of WO prophage and transposable

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

    Science.gov (United States)

    Lupi, Eleonora; Hatz, Christoph; Schlagenhauf, Patricia

    2013-01-01

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

  15. Competence of Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus Mosquitoes as Zika Virus Vectors, China

    Science.gov (United States)

    Liu, Zhuanzhuan; Zhou, Tengfei; Lai, Zetian; Zhang, Zhenhong; Jia, Zhirong; Zhou, Guofa; Williams, Tricia; Xu, Jiabao; Gu, Jinbao; Zhou, Xiaohong; Lin, Lifeng; Yan, Guiyun

    2017-01-01

    In China, the prevention and control of Zika virus disease has been a public health threat since the first imported case was reported in February 2016. To determine the vector competence of potential vector mosquito species, we experimentally infected Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus mosquitoes and determined infection rates, dissemination rates, and transmission rates. We found the highest vector competence for the imported Zika virus in Ae. aegypti mosquitoes, some susceptibility of Ae. albopictus mosquitoes, but no transmission ability for Cx. quinquefasciatus mosquitoes. Considering that, in China, Ae. albopictus mosquitoes are widely distributed but Ae. aegypti mosquito distribution is limited, Ae. albopictus mosquitoes are a potential primary vector for Zika virus and should be targeted in vector control strategies. PMID:28430562

  16. Larvicidal activity of leguminous seeds and grains against Aedes aegypti and Culex pipiens pallens.

    Science.gov (United States)

    Jang, Young-Su; Baek, Bong-Rae; Yang, Young-Cheol; Kim, Moo-Key; Lee, Hoi-Seon

    2002-09-01

    Larvicidal activity of methanol extracts of 26 leguminous seeds and 20 grains against early 4th-stage larvae of Aedes aegypti and Culex pipiens pallens was examined. At 200 ppm of the extracts from Cassia obtusifolia, Cassia tora, and Vicia tetrasperma, more than 90% mortality was obtained in larvae of Ae. aegypti and Cx. pipiens pallens. Extract of C. tora gave 86.7 and 100% mortality in the larvae of Ae. aegypti and Cx. pipiens pallens at 40 ppm but 59.2 and 78.3% mortality against larvae of Ae. aegypti and Cx. pipiens pallens at 20 ppm, respectively. At 40 ppm, extract of C. obtusifolia caused 51.4 and 68.5% mortality of the 4th-stage larvae of Ae. aegypti and Cx. pipiens pallens, respectively. Larvicidal activity of extract of C obtusifolia was significantly reduced when used at 20 ppm. Further studies of these plants as possible agents for mosquito control are warranted.

  17. Insecticidal and repellent activity of Siparuna guianensis Aubl. (Negramina against Aedes aegypti and Culex quinquefasciatus.

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    Raimundo Wagner Souza Aguiar

    Full Text Available This study investigated the toxic effects of essential oils isolated from Siparuna guianensis against Aedes aegypti, Culex quinquefasciatus (eggs, larvae, pupae, and adult and Aedes albopictus (C6/36 cells. The oviposition-deterring activity, egg viability, and repellence activity in the presence of different essential oils concentrations were determined. The essential oils showed high toxicity to all developmental stages of A. aegypti and C. quinquefasciatus. Furthermore, the oils also showed high repellent activity towards the adult stage of mosquitoes (0.025 to 0.550 μg/cm2 skin conferred 100% repellence up to 120 min and in contact with cultured insect cells (C6/36 induced death possibly by necrosis. The results presented in this work show the potential of S. guianensis essential oils for the development of an alternative and effective method for the natural control of mosquitoes in homes and urban areas.

  18. Insecticidal and repellent activity of Siparuna guianensis Aubl. (Negramina) against Aedes aegypti and Culex quinquefasciatus.

    Science.gov (United States)

    Aguiar, Raimundo Wagner Souza; dos Santos, Suetonio Fernandes; da Silva Morgado, Fabricio; Ascencio, Sergio Donizeti; de Mendonça Lopes, Magnólia; Viana, Kelvinson Fernandes; Didonet, Julcemar; Ribeiro, Bergmann Morais

    2015-01-01

    This study investigated the toxic effects of essential oils isolated from Siparuna guianensis against Aedes aegypti, Culex quinquefasciatus (eggs, larvae, pupae, and adult) and Aedes albopictus (C6/36) cells. The oviposition-deterring activity, egg viability, and repellence activity in the presence of different essential oils concentrations were determined. The essential oils showed high toxicity to all developmental stages of A. aegypti and C. quinquefasciatus. Furthermore, the oils also showed high repellent activity towards the adult stage of mosquitoes (0.025 to 0.550 μg/cm2 skin conferred 100% repellence up to 120 min) and in contact with cultured insect cells (C6/36) induced death possibly by necrosis. The results presented in this work show the potential of S. guianensis essential oils for the development of an alternative and effective method for the natural control of mosquitoes in homes and urban areas.

  19. Evaluation of factors for rapid development of Culex quinquefasciatus in belowground stormwater treatment devices.

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    Harbison, Justin E; Metzger, Marco E; Walton, William E; Hu, Renjie

    2009-12-01

    Water samples from 11 belowground stormwater treatment Best Management Practices (BMPs) were evaluated for their capacity to support rapid development of the West Nile virus (WNV) mosquito vector, Culex quinquefasciatus. The observed minimum development time from egg to pupa ranged from six to over 30 days. Concentrations of potential food resources (total suspended solids and the particulate organic matter in water samples) were significantly correlated to development times. In addition, the rate of immature mosquito development was both site-dependent and variable in time, suggesting that factors favorable to rapid development were strongly influenced by watershed characteristics and seasonal changes in temperature. Measured temperatures in belowground BMPs suggest that these structures may remain amenable to WNV virus activity longer each year than sites aboveground.

  20. PATOGENITAS CENDAWAN BEAUVERIA BASSIANA TERHADAP LARVA NYAMUK AEDES AEGYPTI DAN CULEX PIPIENS QUINQUEFASCIATUS DI LABORATORIUM

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    Amrul Munif

    2012-09-01

    Full Text Available The capability of Beauveria bassiana fungus to kill mosquito larvae was challenged with Aedes aegypti and Culex pipiens quinquefasciatus in a study conducted at the entomology laboratory of the Health Ecology Research Centre. Cx. p. quinquefeasciatus was more sensitive compared to Ae. aegypti to the B. bassiana strain from Sukamandi (West Java, which is probably due to the mosquitoes behaviour and conidiospore larvacidal effect. Conidia dust application, with a dosage of 2.2 mglliter, to water surface, within 48 hours was able to kill almost all the Cx. p. quinquefasciatus. However a dosage of 4 mglliter was required to kill all the Ae.aegypti. And a dosage of 1.3 mg conidiospore I liter is able to kill 50% Cx. p. quinquefasciatus. It seems that B. bassiana has greater capability to eradicate Cx. p. quinquefasciatus compared to Ae. aegypti

  1. Toxicities of Organophosphate and Carbamat Insecticide Against Culex quinquefasciatus Mosquito Larvae

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    Endang Puji Astuti

    2009-06-01

    Full Text Available Culex quinquefasciatus mosquito is increasing problem of public health, being the vector responsible for West Nile Virus and Filariasis. Chlorpirifos (Organofosfat and Metonil (Carbamat were known to posses insecticide activity against insect. The study was aimed to examine effectiveness of Klorpirifos and Metonil as larvicide against C. quinquefasciatus larval. Chlorpirifos a significantly higher larvicidal activity against 3th-4th instar larvae of C. quinquefasciatus than Metonil. The larval mortality was observed after 24-h exposure. The LC95 value of Chlorpirifos and Metonil were 3,139 mg/lt and 9,045 mg/lt, against C. quinquefasciatus. The mixed of both insecticide was LC95 value 2,823 mg/lt. The result of this study suggested that Chlorpirifos more effective larvicide against C. quinquefasciatus than Metonil.

  2. Characterization of Dak Nong virus, an insect nidovirus isolated from Culex mosquitoes in Vietnam.

    Science.gov (United States)

    Kuwata, Ryusei; Satho, Tomomitsu; Isawa, Haruhiko; Yen, Nguyen Thi; Phong, Tran Vu; Nga, Phan Thi; Kurashige, Tomokazu; Hiramatsu, Yukihiro; Fukumitsu, Yuki; Hoshino, Keita; Sasaki, Toshinori; Kobayashi, Mutsuo; Mizutani, Tetsuya; Sawabe, Kyoko

    2013-11-01

    In this study, we isolated and characterized an insect nidovirus from the mosquito Culex tritaeniorhynchus Giles (Diptera: Culicidae) in Vietnam, as an additional member of the new family Mesoniviridae in the order Nidovirales. The virus, designated "Dak Nong virus (DKNV)," shared many characteristics with Cavally virus and Nam Dinh virus, which have also been discovered recently in mosquitoes, and these viruses should be considered members of a single virus species, Alphamesonivirus 1. DKNV grew in cultured mosquito cells but could not replicate in the cultured vertebrate cells tested. N-terminal sequencing of the DKNV structural proteins revealed two posttranslational cleavage sites in the spike glycoprotein precursor. DKNV is assumed to be a new member of the species Alphamesonivirus 1, and the current study provides further understanding of viruses belonging to the new family Mesoniviridae.

  3. Temperature effects on the immature development time of Culex eduardoi Casal and Garcia (Diptera: Culicidae)

    Energy Technology Data Exchange (ETDEWEB)

    Loetti, V.; Schweigmann, N.J.; Burroni, N.E., E-mail: nburroni@ege.fcen.uba.a [Universidad de Buenos Aires (Argentina). Facultad de Ciencias Exactas y Naturales. Grupo de Estudio de Mosquitos

    2011-01-15

    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)

  4. Screening of twenty five plant extracts for larvicidal activity against Culex quinquefasciatus Say (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Samuel Tennyson; K John Ravindran; S Arivoli

    2012-01-01

    Objective: To determine the larvicidal activity of twenty five plant extracts against Culex quinquefasciatus (Cx. quinquefasciatus). Methods: The larvicidal activity was determined against the third instar larvae of Cx. quinquefasciatus at 1 000 ppm concentration. Larval mortality was assessed after 24 and 48 h. Results: The hexane extracts of Cleistanthus collinus (C. collinus) and Murraya koeingii (M. koeingii) plants showed 100 percent mortality at 24 h bioassay followed by diethyl ether, dichloromethane and ethyl acetate extracts of C. collinus, Leucas aspera (L. aspera), Hydrocotyle javanica (H. javanica), M. koeingii, Sphaeranthus indicus (S. indicus) and Zanthoxylum limonella (Z. limonella) after 48 h exposure. Conclusions: The results indicate larvicidal activity against Cx. quinquefasciatus and further investigations are needed to elucidate this activity against a wide range of all stages of mosquito species and also the active ingredients of the extract responsible for larvicidal activity should be identified.

  5. Larvicidal activity of synthetic disinfectants and antibacterial soaps against mosquito, Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Xue, Rui-De; Qualls, Whitney A

    2013-01-01

    Seven commercial synthetic disinfectant and antibacterial soap products were evaluated as mosquito larvicides against Culex quinquefasciatus Say in the laboratory. Three aerosol disinfectant products, at 0.01% concentration resulted in 58-76% mortality of laboratory-reared fourth instar mosquito larvae at 24 h posttreatment. Four antibacterial soap products at 0.0001% concentration resulted in 88-100% larval mortality at 24 h posttreatment. The active ingredient of the antibacterial soap products, triclosan (0.1%) resulted in 74% larval mortality. One of the antibacterial soap products, Equate caused the highest mosquito larval mortality in the laboratory. Equate antibacterial soap at the application rate of 0.000053 ppm resulted in 90% mortality of the introduced fourth instar larvae of Cx. quinquesfasicatus in the outdoor pools. In laboratory and field bioassays, the antibacterial soap resulted in significant larval mosquito mortality.

  6. Repellency effect of forty-one essential oils against Aedes, Anopheles, and Culex mosquitoes.

    Science.gov (United States)

    Amer, Abdelkrim; Mehlhorn, Heinz

    2006-09-01

    Since ancient times, plant products were used in various aspects. However, their use against pests decreased when chemical products became developed. Recently, concerns increased with respect to public health and environmental security requiring detection of natural products that may be used against insect pests. In this study, 41 plant extracts and 11 oil mixtures were evaluated against the yellow fever mosquito, Aedes aegypti (Linnaeus), the malaria vector, Anopheles stephensi (Liston), and the filariasis and encephalitis vector, Culex quinquefasciatus (Say) (Diptera: Culicidae) using the skin of human volunteers to find out the protection time and repellency. The five most effective oils were those of Litsea (Litsea cubeba), Cajeput (Melaleuca leucadendron), Niaouli (Melaleuca quinquenervia), Violet (Viola odorata), and Catnip (Nepeta cataria), which induced a protection time of 8 h at the maximum and a 100% repellency against all three species. This effect needs, however, a peculiar formulation to fix them on the human skin.

  7. Bionomics of Culex epidesmus associated with Japanese encephalitis virus in India.

    Science.gov (United States)

    Kanojia, P C

    2003-06-01

    Various biological characteristics, including seasonal abundance, diurnal resting habits, feeding behavior, larval habitats, and oviposition, of Culex epidesmus were studied in Gorakhpur District, Uttar Pradesh, India, from 1990 to 1999. Prevalence of adults was recorded between June and October, with a peak in August. The bushy undergrowth of mango and teakwood plantations served as diurnal resting habitat. Blood-meal analysis of wild-caught females showed that the most of them had fed on bovines. Temporary pools of rainwater and paddy fields containing freshwater and filamentous green algae were found to be suitable larval habitats. Gravid females laid eggs and immature stages grew well in the presence of green algae. Freshly laid egg rafts were found to be boat shaped and individual eggs were a white-cream color. The number of eggs per raft deposited by individual Cx. epidesmus varied from 118 to 288, with an average of 199 eggs per specimen.

  8. A first note on Japanese encephalitis virus isolation from Culex quinquefasciatus Say in Northern West Bengal.

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    V. Thenmozhi

    2014-03-01

    Full Text Available Japanese encephalitis (JE is endemic in many parts of India including the state of West Bengal. In West Bengal, the first major outbreaks of JE occurred in the districts of Bankura and Burdwan in 1973. The Culex vishnui subgroup of mosquitoes has been implicated as major vectors of JE. However in India, JE virus (JEV has been isolated from 16 species of mosquitoes. During September 2011, JE cases were reported from four districts -Jalpaiguri, Darjeeling, Dinajpur and Cooch Behar of West Bengal (North. Adult mosquitoes were collected, identified, pooled and screened for JEV using antigen capture ELISA. Out of 279 mosquito pools tested, one pool of Cx. pseudovishnui and three pools of Cx. quinquefasciatus were found positive for JEV. The ELISA positive pools were further confirmed as JEV by insect bioassay (Toxo-IFA. Two pools of Cx. quinquefasciatus were confirmed as JEV. This represents the first report of JEV isolation from Cx. quinquefasciatus in West Bengal.

  9. Larvicidal activity of Lawsonia inermis and Murraya exotica leaves extract on filarial vector, Culex quinquefasciatus.

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    K. Dass

    2014-06-01

    Full Text Available Extensive use of synthetic and chemical insecticides to control mosquitoes result in environment hazards and development of resistance in vector species. This research work is about an alternative mosquito control method that is considered as safe to environment and non-target species and also bio-degradable. Hence an attempt was made to study the larvicidal effect of the extract of Lawsonia inermis and Murraya exotica leaves on III and IV instar larva and pupa of Culex quinquefasciatus. The LC50 value of Murraya exotica for III and IV instar larvae and pupae is 135.539 ppm, 154.361 ppm and 178.571 ppm respectively. Likewise for Lawsonia inermis it is 139.057 for III instar, 163.630 for IV instar and 188.151 for the pupa. Of these, two plants Murraya exotica plant extract is more effective than the Lawsonia inermis.

  10. Evaluation of Water and Ethanol Extract of Eucalyptus globulus Labillardiere (Myrtaceae) Leaves against Immature Stages of Filarial Vector Culex quinquefasciatus Say (Diptera: Culicidae)

    OpenAIRE

    Angesom Tesfay; Azmera W/Yowhanns; Endahafit Niguse; Guesh Brhane; Selamawit Brhane; Raja Nagappan

    2012-01-01

    Aim of the present study was to evaluate larvicidal and pupicidal effect of aqueous and ethanol extract of Eucalyptus globulus leaves against immature stages of Culex mosquitoes. The experiment was conducted in the Botany Laboratory, University of Gondar, Gondar from February 2011 to May 2011. The standard WHO protocol was used to check five concentrations such as 100, 250, 500, 750 and 1000 ppm against II, III, IVth instar larvae and pupae of Culex mosquitoes, respectively. Irrespective of t...

  11. Correlation between carboxylesterase alleles and insecticide resistance in Culex pipiens complex from China

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    Liu Yangyang

    2011-12-01

    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".

  12. Culex quinquefasciatus from Rio de Janeiro Is Not Competent to Transmit the Local Zika Virus.

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    Rosilainy Surubi Fernandes

    2016-09-01

    Full Text Available The Americas have suffered a dramatic epidemic of Zika since May in 2015, when Zika virus (ZIKV was first detected in Brazil. Mosquitoes belonging to subgenus Stegomyia of Aedes, particularly Aedes aegypti, are considered the primary vectors of ZIKV. However, the rapid spread of the virus across the continent raised several concerns about the transmission dynamics, especially about potential mosquito vectors. The purpose of this work was to assess the vector competence of the house mosquito Culex quinquefasciatus from an epidemic Zika area, Rio de Janeiro, Brazil, for local circulating ZIKV isolates.Culex quinquefasciatus and Ae. aegypti (positive control of ZIKV infection from Rio de Janeiro were orally exposed to two ZIKV strains isolated from human cases from Rio de Janeiro (Rio-U1 and Rio-S1. Fully engorged mosquitoes were held in incubators at 26 ± 1°C, 12 h:12 h light:dark cycle and 70 ± 10% humidity. For each combination mosquito population-ZIKV strain, 30 specimens were examined for infection, dissemination and transmission rates, at 7, 14 and 21 days after virus exposure by analyzing body (thorax plus abdomen, head and saliva respectively. Infection rates were minimal to completely absent in all Cx. quinquefasciatus-virus combinations and were significantly high for Ae. aegypti. Moreover, dissemination and transmission were not detected in any Cx. quinquefasciatus mosquitoes whatever the incubation period and the ZIKV isolate. In contrast, Ae. aegypti ensured high viral dissemination and moderate to very high transmission.The southern house mosquito Cx. quinquefasciatus from Rio de Janeiro was not competent to transmit local strains of ZIKV. Thus, there is no experimental evidence that Cx. quinquefasciatus likely plays a role in the ZIKV transmission. Consequently, at least in Rio, mosquito control to reduce ZIKV transmission should remain focused on Ae. aegypti.

  13. An impossible journey? The development of Plasmodium falciparum NF54 in Culex quinquefasciatus.

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    Julia Knöckel

    Full Text Available Although Anopheles mosquitoes are the vectors for human Plasmodium spp., there are also other mosquito species-among them culicines (Culex spp., Aedes spp.-present in malaria-endemic areas. Culicine mosquitoes transmit arboviruses and filarial worms to humans and are vectors for avian Plasmodium spp., but have never been observed to transmit human Plasmodium spp. When ingested by a culicine mosquito, parasites could either face an environment that does not allow development due to biologic incompatibility or be actively killed by the mosquito's immune system. In the latter case, the molecular mechanism of killing must be sufficiently powerful that Plasmodium is not able to overcome it. To investigate how human malaria parasites develop in culicine mosquitoes, we infected Culex quinquefasciatus with Plasmodium falciparum NF54 and monitored development of parasites in the blood bolus and midgut epithelium at different time points. Our results reveal that ookinetes develop in the midgut lumen of C. quinquefasciatus in slightly lower numbers than in Anopheles gambiae G3. After 30 hours, parasites have invaded the midgut and can be observed on the basal side of the midgut epithelium by confocal and transmission electron microscopy. Very few of the parasites in C. quinquefasciatus are alive, most of them are lysed. Eight days after the mosquito's blood meal, no oocysts can be found in C. quinquefasciatus. Our results suggest that the mosquito immune system could be involved in parasite killing early in development after ookinetes have crossed the midgut epithelium and come in contact with the mosquito hemolymph.

  14. Culex quinquefasciatus from Rio de Janeiro Is Not Competent to Transmit the Local Zika Virus

    Science.gov (United States)

    Ferreira-de-Brito, Anielly; de Miranda, Rafaella Moraes; Barbosa da Silva, Keli Antunes; de Castro, Marcia Gonçalves; Raphael, Lidiane M. S.; Failloux, Anna-Bella; Bonaldo, Myrna C.; Lourenço-de-Oliveira, Ricardo

    2016-01-01

    Background The Americas have suffered a dramatic epidemic of Zika since May in 2015, when Zika virus (ZIKV) was first detected in Brazil. Mosquitoes belonging to subgenus Stegomyia of Aedes, particularly Aedes aegypti, are considered the primary vectors of ZIKV. However, the rapid spread of the virus across the continent raised several concerns about the transmission dynamics, especially about potential mosquito vectors. The purpose of this work was to assess the vector competence of the house mosquito Culex quinquefasciatus from an epidemic Zika area, Rio de Janeiro, Brazil, for local circulating ZIKV isolates. Methodology/Principal Findings Culex quinquefasciatus and Ae. aegypti (positive control of ZIKV infection) from Rio de Janeiro were orally exposed to two ZIKV strains isolated from human cases from Rio de Janeiro (Rio-U1 and Rio-S1). Fully engorged mosquitoes were held in incubators at 26 ± 1°C, 12 h:12 h light:dark cycle and 70 ± 10% humidity. For each combination mosquito population—ZIKV strain, 30 specimens were examined for infection, dissemination and transmission rates, at 7, 14 and 21 days after virus exposure by analyzing body (thorax plus abdomen), head and saliva respectively. Infection rates were minimal to completely absent in all Cx. quinquefasciatus-virus combinations and were significantly high for Ae. aegypti. Moreover, dissemination and transmission were not detected in any Cx. quinquefasciatus mosquitoes whatever the incubation period and the ZIKV isolate. In contrast, Ae. aegypti ensured high viral dissemination and moderate to very high transmission. Conclusions/Significance The southern house mosquito Cx. quinquefasciatus from Rio de Janeiro was not competent to transmit local strains of ZIKV. Thus, there is no experimental evidence that Cx. quinquefasciatus likely plays a role in the ZIKV transmission. Consequently, at least in Rio, mosquito control to reduce ZIKV transmission should remain focused on Ae. aegypti. PMID

  15. Reproductive biology and susceptibility of Florida Culex coronator to infection with West Nile virus.

    Science.gov (United States)

    Alto, Barry W; Connelly, C Roxanne; O'Meara, George F; Hickman, Dustin; Karr, Nicholas

    2014-08-01

    Abstract Ornithophilic Culex species are considered the primary amplification vectors of West Nile virus (WNV) in bird hosts as well as vectors responsible for epidemic transmission. Culex coronator was first collected from Okaloosa, Santa Rosa, Walton, and Washington Counties in Florida in 2005 and has since spread throughout the state. The vector competence of Cx. coronator for WNV, known to be infected in nature, has not been assessed. Without this knowledge, we are unable to assess this species' potential as an enzootic and epidemic vector of WNV in Florida. In the current study, we investigate the reproductive biology and susceptibility to WNV infection, dissemination, and transmission by Cx. coronator. We show that Cx. coronator is capable of delaying oviposition for several weeks after blood feeding and that the number of eggs laid is greater for avian than mammalian hosts. Cx. coronator were highly susceptible to infection (∼80-100%) and dissemination (∼65-85% by 18 days since exposure) with lower rates of transmission (0-17% at 25°C and 28-67% at 28°C), suggesting that it is a competent vector of WNV under some conditions. The proportion of mosquitoes with disseminated infections related to the time since exposure and was higher at 28°C than at 25°C. The rapid and statewide distribution of Cx. coronator throughout Florida poses as a potential public health risk. This baseline knowledge is essential information for mosquito control and public health agencies to assess current and future disease risk to Southeastern United States.

  16. 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

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    Susana R. Cagnolo

    2010-06-01

    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.

  17. Avaliação da sensibilidade de adultos de Culex quinquefasciatus Say a inseticidas químicos de contato Evaluation of the sensitivity of the adult Culex quinquefasciatus Say to chemical insecticides

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    Carlos Fernando S. de Andrade

    1990-08-01

    Full Text Available A sensibilidade de adultos do pernilongo doméstico Culex quinquefasciatus a 5 inseticidas químicos foi avaliada sob condições de laboratório pelo critério de Tempo Letal Mediano (TL50. Foram utilizados o organofosforado Malathion e quatro piretróides: Bifenthrin, Deltamethrin, Esfenvalerate e Alfamethrin. Foi sugerida uma técnica simples e eficiente para se avaliar adultos de um dia de idade incluindo 5 repetições para cada tratamento. Os resultados obtidos mostraram ser o método bastante adequado para avaliações rotineiras. Não ocorreu resistência a esses 5 princípios ativos, na população natural de Culex quinquefasciatus estudada.The sensitivity of the adult house mosquito Culex quinquefasciatus to 5 chemical insecticides was evaluated under laboratory condictions, based on the Median Lethal Time (LT50 criterion. The organophosphorous Malathion and four pyrethroids: Bifenthrin, Deltamethrin, Esfenvalerate and Alfamethrin were utilized. An easy and efficient technique was suggested for the testing of one-day-old adults, including five repetitions for each treatment. The results revealed the full adequacy of this method for routine use. Further, no resistance to the 5 chemical compounds was detected among this natural population of Cx. quinquefasciatus.

  18. Efficacy ofLimonia acidissima L. (Rutaceae) leaf extract on larval immatures of Culex quinquefasciatus Say 1823

    Institute of Scientific and Technical Information of China (English)

    Siddharthasankar Banerjee; Someshwar Singha; Subrata Laskar; Goutam Chandra

    2011-01-01

    Objective:To investigate the role of leaf extract ofLimonia acidissimaL. (Rutaceae) as a biocontrol agent against the larval form ofCulex quinquefasciatus, and characterization of bioactive component responsible for larvicidal activity.Methods:Larval mortality of mosquito species was observed after24, 48and72 hours of exposure to different concentrations of aqueous extract, solvent extract and subsequently bioactive compound. The bioactive compound was subjected toIR andGC-MS analysis.Results:Mortality rate at 3% concentration of crude extract were highest(90%) amongst all concentrations tested and subsequently highest(95%) mortality was achieved in chloroform: methanol extract at100 ppm concentrations. IRandGC-MS analysis of bioactive compound revealed the presence of steroid compound which may act as larvicide. Conclusions:The chloroform: methanol extract of mature leaves of Limonia acidissima was found to exhibit considerable mosquito larvicidal activity against Culex quinquefasciatus.

  19. Immature Aedes mosquitoes colonize Culex quinquefasciatus breeding sites in neighborhoods in the municipality of Olinda, State of Pernambuco

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    Suzane Alves dos Santos

    2014-12-01

    Full Text Available Introduction The present study shows the colonization of Aedes mosquitoes in breeding sites specific for Culex quinquefasciatus in neighborhoods in the municipality of Olinda. Methods Samples were collected between May 2011 and June 2012 from breeding sites positive for Cx. quinquefasciatus by using a ladle and manual suction pump. Results Aedes aegypti (0.12%, Aedes albopictus (0.03%, and Cx. quinquefasciatus (99.8% were found across the breeding sites. Conclusions The presence of Aedes ssp. in several Cx. quinquefasciatus breeding sites with a heavy load of organic material demonstrates the need to review the concepts and methods used for treatment, as the use of specific larvicide for breeding sites of Culex.

  20. Taxonomic studies on Culex (Melanoconion coppenamensis Bonne-Wepster & Bonne (Diptera: Culicidae, and description of two new species from Brazil

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    Maria Anice Mureb Sallum

    2003-07-01

    Full Text Available Two new species,Culex (Melanoconion alinkios and Culex (Melanoconion symbletos are described and defined based on morphological features of the male genitalia. The former is from Vale do Ribeira, Atlantic Forest, southeastern of the state of São Paulo, Brazil, and belongs to the Bastagarius subgroup. The latter is from the Parque Nacional do Jaú, state of Amazonas, Brazil, and belongs to the Inhibitator subgroup and is similar to Cx. mesodenticulatus Galindo and Mendez. Diagnostic characters for the identification of the adult males of the species are provided. Two morphological forms (Form 1 and 2, which are similar to Cx. coppenamensis, were also found in the Parque Nacional do Jaú. Form 1 is described and compared with the new species from Vale do Ribeira and Form 2.

  1. Effects of forced egg retention on the temporal progression of West Nile virus infection in Culex pipiens quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Smartt, Chelsea T; Richards, Stephanie L; Anderson, Sheri L; Vitek, Christopher J

    2010-02-01

    Environmental factors that impact the biology of mosquito vectors can have epidemiological implications. Lack of oviposition sites facilitated by environmental factors such as temperature and drought can often force Culex spp. mosquitoes to retain their eggs. Culex pipiens quinquefasciatus Say were fed blood meals containing West Nile virus (WNV; family Flaviviridae, genus Flavivirus) and either allowed to oviposit or forced to retain their eggs through different time points postinfection (9, 13, 20, 27 d) at 28 degrees C. Oviposition status did not significantly affect rates of WNV infection (% with virus-positive bodies), dissemination (% with virus-positive legs), or transmission (% with virus-positive saliva) for any of the tested time points. As expected, WNV titers in bodies and legs were significantly (P studies are needed to assess the effects of drought on virus transmission risk and how these interactions affect our interpretation of field data.

  2. Multiple resistance of Culex vishnui Theobald against four major classes of insecticides in an agricultural area in Sekinchan, Selangor, Malaysia.

    Science.gov (United States)

    Leong, C S; Chen, C D; Low, V L; Karen-Chia, H M; Azidah, A A; Sofian-Azirun, M

    2014-06-01

    The resistance status of riceland Culex vishnui against four major groups of insecticides (i.e., organochlorines, carbamates, organophosphates and pyrethroids) was investigated. Biochemical assays (ESTα, ESTβ, MFO and GST) were also conducted to detect the resistance levels. Throughout a 12-month study period, multiple insecticide resistance was observed in both larvae and adult Cx vishnui. Culex vishnui larvae exhibited low resistance against malathion, temephos and permethrin with resistance ratio (RR) values GST. Spearman rank-order analysis showed that ESTα, ESTβ and GST were involved in multiple resistances in Cx. vishnui. The findings of this study established a baseline of insecticide susceptibility and revealed the effects of agricultural insecticide pressure on the vectors of Japanese encephalitis in Malaysia.

  3. Effects of larval rearing temperature on immature development and West Nile virus vector competence of Culex tarsalis

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    Dodson Brittany L

    2012-09-01

    Full Text Available Abstract Background Temperature is known to induce changes in mosquito physiology, development, ecology, and in some species, vector competence for arboviruses. Since colonized mosquitoes are reared under laboratory conditions that can be significantly different from their field counterparts, laboratory vector competence experiments may not accurately reflect natural vector-virus interactions. Methods We evaluated the effects of larval rearing temperature on immature development parameters and vector competence of two Culex tarsalis strains for West Nile virus (WNV. Results Rearing temperature had a significant effect on mosquito developmental parameters, including shorter time to pupation and emergence and smaller female body size as temperature increased. However, infection, dissemination, and transmission rates for WNV at 5, 7, and 14 days post infectious feeding were not consistently affected. Conclusions These results suggest that varying constant larval rearing temperature does not significantly affect laboratory estimates of vector competence for WNV in Culex tarsalis mosquitoes.

  4. [The effect of insecticide resistance on the demographic parameters of 3 strains of Culex quinquefasciatus (Diptera: Culicidae) under laboratory conditions].

    Science.gov (United States)

    Suárez, S; Montada, D; Fuentes, O; Castex, M; Leyva, M

    1998-01-01

    The life tables of 3 strains of Culex quinquefasciatus were studied under laboratory conditions: Slab, susceptible to reference; Old Havana, treated with cypermethrin until its fourth generation; and Cotorro, from the field. It was found that the different levels of resistance to organophosphate insecticides and pyrethroids present in the Cotorro and Old Havana strains did not influence either on the duration of the period of development of the immature stages or in the sexual proportion of the emerged adults, but they had a favorable and directly proportional effect on the survival and longevity of the adults. However, they exerted a negative and inversely proportional influence on the reproduction and population growth of these strains. Useful data for the use and management of insecticides within the strategies of control of Culex quinquefasciatus, an important vector of lymphatic filariasis, are provided.

  5. Rotational application of bioinsecticide with deltamethrin-An antilarval measure for the control of filarial vector, Culex quinquefasciatus (Culicidae: Diptera).

    Science.gov (United States)

    Gayathri, V; Jeyalakshmi, T; Shanmugasundaram, R; Murthy, P Balakrishna

    2004-10-01

    A laboratory investigation was undertaken to study the cyclic usage of field recommended doses of Bacillus thuringiensis israelensis (Bti), Bacillus sphaericus (Bsp) and combination of Bti and Bsp (half the recommended dose of each) with deltamethrin 2.8 EC to attain better control of mosquito larvae. To understand the susceptibility status of the Culex quinquefasciatus larvae in the field, early fourth instar field collected larvae were exposed to the above treatments of biopesticides and were monitored for their persistency till 50% mortality was obtained. The larvae those survived in each treatment were transferred to the concentration of deltamethrin that gave 50% mortality. Observations on larval mortality after the treatment with deltamethrin were recorded after 24 h. The results revealed that Bti excels Bsp, as it recorded 54% mortality only on 17th day after application. The other salient finding of this study is LC50 of deltamethrin is sufficient to follow the biopesticides application for an effective control of Culex larvae.

  6. Ovicidal and Oviposition Deterrent Activities of Medicinal Plant Extracts Against Aedes aegypti L. and Culex quinquefasciatus Say Mosquitoes (Diptera: Culicidae)

    OpenAIRE

    Reegan, Appadurai Daniel; Gandhi, Munusamy Rajiv; Paulraj, Micheal Gabriel; Ignacimuthu,Savarimuthu

    2014-01-01

    Objectives To evaluate the ovicidal and oviposition deterrent activities of five medicinal plant extracts namely Aegle marmelos (Linn.), Limonia acidissima (Linn.), Sphaeranthus indicus (Linn.), Sphaeranthus amaranthoides (burm.f), and Chromolaena odorata (Linn.) against Culex quinquefasciatus and Aedes aegypti mosquitoes. Three solvents, namely hexane, ethyl acetate, and methanol, were used for the preparation of extracts from each plant. Methods Four different concentrations—62.5 parts per ...

  7. EFIKASI LARVASIDA BERBAHAN AKTIF BENZOYL PHENIL UREA SEBAGAI INSECT GROWTH REGULATOR TERHADAP LARVA Culex quinquefasciatus DI LABORATORIUM

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    Siti Alfiah

    2014-06-01

    Full Text Available This study was conducted to determine the efficacy of an insect growth regulator (IGRbenzoyl phenil urea against Culex quinquefasciatus larvae, laboratory scale trial. The researchused seven concentrations of IGR, were evaluated 0,5 ; 1 ; 2 ; 2,5 ; 3 and 5 ppm and untreatedcontrol, using 4 replications (20 larvae each. The result showed that 0,5 ppm of the benzoylphenil urea could kill more 90% of Cx. quinquefasciatus larvae in 5 days, while concentrations 1; 2 ; 2,5 and 3 ppm in 4 days, and concentration 5 ppm in 3 days. The result was also revealedthat LC50 and LC90 0,57 and 23,2 ppm. Mosquito larvae mortalities were showed statisticallydifferent among concentrations (p < 0,05.Key words : Efficacy, benzoyl phenil urea, Culex quinquefasciatus Penelitian untuk mengetahui efikasi insect growth regulator (IGR benzoyl phenil ureaterhadap larva Culex quinquefasciatus telah dilakukan. Penelitian menggunakan 7 konsentrasipengujian yaitu 0,5 ppm, 1 ppm, 2 ppm, 2,5 ppm, 3 ppm, 5 ppm dan kontrol. Setiap konsentrasimenggunakan 4 kali pengulangan. Hasil menunjukkan bahwa larvasida benzoyl phenil ureamembunuh lebih dari 90% larva Cx. quinquefasciatus dengan konsentrasi 0,5 ppm dalam 5 hari,konsentrasi 1 ; 2 ; 2,5 dan 3 ppm dalam waktu 4 hari dan konsentrasi 5 ppm dalam waktu 3 hari.Konsentrasi yang diperlukan untuk membunuh 50% (LC50 dan 90% (LC90 larva uji adalah 0,57ppm dan 23,2 ppm. Uji analisis varian memberikan hasil bahwa ada perbedaan bermaknakematian larva antar konsentrasi pada taraf nyata 5%.Kata kunci : Efikasi, benzoyl phenil urea, Culex quinquefasciatus

  8. Development of a Bacillus sphaericus tablet formulation and its evaluation as a larvicide in the biological control of Culex quinquefasciatus

    OpenAIRE

    Flávia P Morais de Medeiros; Maria Alice Varjal de Melo Santos; Leda Regis; Eugênia M Maranhão Rios; Pedro J. Rolim Neto

    2005-01-01

    This study aimed to analyze the final fermentation culture of Bacillus sphaericus 2362, standardize it and develop an active tablet formulation for use in urban mosquito breeding sites. It was performed in three phases: analysis and standardization of a B. sphaericus fermented culture; physical, chemical, and biological analysis of the active powder (solubility, residual humidity, particle size, resting angle, flowing off time, compacted density, and biological activity against Culex quinquef...

  9. Development of a Bacillus sphaericus tablet formulation and its evaluation as a larvicide in the biological control of Culex quinquefasciatus

    OpenAIRE

    Flávia P. Morais de Medeiros; Maria Alice Varjal de Melo Santos; Leda Regis; Eugênia M Maranhão Rios; Rolim Neto,Pedro J

    2005-01-01

    This study aimed to analyze the final fermentation culture of Bacillus sphaericus 2362, standardize it and develop an active tablet formulation for use in urban mosquito breeding sites. It was performed in three phases: analysis and standardization of a B. sphaericus fermented culture; physical, chemical, and biological analysis of the active powder (solubility, residual humidity, particle size, resting angle, flowing off time, compacted density, and biological activity against Culex quinquef...

  10. Resistência a inseticidas organofosforados e carbamatos em população de Culex quinquefasciatus

    OpenAIRE

    Bracco José Eduardo; Dalbon Moacyr; Marinotti Osvaldo; Barata José Maria Soares

    1997-01-01

    Relata-se a ocorrência, na população de Culex quinquefasciatus, de resistência a pelo menos dois organofosforados e a um carbamato (malathion, fenitrothion e propoxur, respectivamente), mostrando a necessidade de haver programa de manejo de inseticidas. A suscetibilidade dessa população ao piretróide permetrina indica essa classe como de escolha numa eventual necessidade de substituição dos organofosforados.

  11. Resistência a inseticidas organofosforados e carbamatos em população de Culex quinquefasciatus

    Directory of Open Access Journals (Sweden)

    Bracco José Eduardo

    1997-01-01

    Full Text Available Relata-se a ocorrência, na população de Culex quinquefasciatus, de resistência a pelo menos dois organofosforados e a um carbamato (malathion, fenitrothion e propoxur, respectivamente, mostrando a necessidade de haver programa de manejo de inseticidas. A suscetibilidade dessa população ao piretróide permetrina indica essa classe como de escolha numa eventual necessidade de substituição dos organofosforados.

  12. Barcoding Turkish Culex mosquitoes to facilitate arbovirus vector incrimination studies reveals hidden diversity and new potential vectors.

    Science.gov (United States)

    Gunay, Filiz; Alten, Bulent; Simsek, Fatih; Aldemir, Adnan; Linton, Yvonne-Marie

    2015-03-01

    As a precursor to planned arboviral vector incrimination studies, an integrated systematics approach was adopted using morphology and DNA barcoding to examine the Culex fauna present in Turkey. The mitochondrial COI gene (658bp) were sequenced from 185 specimens collected across 11 Turkish provinces, as well as from colony material. Although by morphology only 9 species were recognised, DNA barcoding recovered 13 distinct species including: Cx. (Barraudius) modestus, Cx. (Culex) laticinctus, Cx. (Cux.) mimeticus, Cx. (Cux.) perexiguus, Cx. (Cux.) pipiens, Cx. (Cux.) pipiens form molestus, Cx. (Cux.) quinquefasciatus, Cx. (Cux.) theileri, Cx. (Cux.) torrentium, Cx. (Cux.) tritaeniorhynchus and Cx. (Maillotia) hortensis. The taxon formerly identified as Cx. (Neoculex) territans was shown to comprise two distinct species, neither of which correspond to Cx. territans s.s. These include Cx. (Neo.) impudicus and another uncertain species, which may be Cx. (Neo.) europaeus or Cx. (Neo.) martinii (herein=Cx. (Neo.) sp. 1). Detailed examination of the Pipiens Group revealed Cx. pipiens, Cx. pipiens f. molestus and the widespread presence of the highly efficient West Nile virus vector Cx. quinquefasciatus for the first time. Four new country records are reported, increasing the Culex of Turkey to 15 recognised species and Cx. pipiens f. molestus. A new taxonomic checklist is provided, annotated with respective vector competencies for transmission of arboviruses.

  13. Evaluation of four sampling techniques for surveillance of Culex quinquefasciatus (Diptera: Culicidae) and other mosquitoes in African rice agroecosystems.

    Science.gov (United States)

    Muturi, Ephantus J; Mwangangi, Joseph; Shililu, Josephat; Muriu, Simon; Jacob, Benjamin; Mbogo, Charles M; John, Githure; Novak, Robert

    2007-05-01

    Field studies were conducted in a rice, Oryza sativa L., agroecosystem in Mwea Kenya to compare the efficiency of CO2-baited Centers for Disease Control (CDC) light traps against nonbaited CDC light traps and gravid traps against oviposition traps in outdoor collection of Culex quinquefasciatus Say (Diptera: Culicidae) and other mosquitoes. Collectively, 21 mosquito species from the genera Culex, Anopheles, Mansonia, Ficalbia, and Aedes were captured during the 10-wk study period. Cx. quinquefasciatus was the predominant species in all trap types with proportions ranging from 57% in the nonbaited CDC light traps to 95% in the gravid traps. Significantly higher numbers of Cx. quinquefasciatus and Culex annulioris Theobald were collected in the CO2-baited CDC light traps than in the nonbaited CDC light traps, but the numbers of other mosquito species, including malaria vectors Anopheles arabiensis Patton and Anopheles funestus Giles did not differ significantly between the two trap types. More Cx. quinquefasciatus females were collected in grass infusion-baited gravid traps than egg rafts of this species in oviposition traps containing the same infusion. Although most mosquitoes captured in CO,-baited and nonbaited CDC light traps were unfed, most of those collected in gravid traps were gravid. From these findings, it is concluded that at least in the rice-growing area of Mwea Kenya, CO2-baited CDC light traps in conjunction with gravid traps can be used in monitoring of Cx. quinquefasciatus both for control and disease surveillance.

  14. Investigation of fathead minnows (Pimephales promelas) as a biological control agent of Culex mosquitoes under laboratory and field conditions.

    Science.gov (United States)

    Irwin, Patrick; Paskewitz, Susan

    2009-09-01

    Many urban areas have engineered storm-water runoff control structures such as ditches and detention ponds. These often serve as excellent habitats for Culex pipiens and Culex restuans, the primary enzootic vectors of West Nile virus in the Midwest. We evaluated predation and control of these species by a fish species native to Wisconsin, the fathead minnow (Pimephales promelas). In the lab, a single minnow consumed an average of 74 Cx. pipiens larvae in a 24-h period. Minnow gender and age had minimal effect on predation of 2nd and 4th instars. In the field, fathead minnows (1,000 fish/ha) were introduced 1 time into 3 storm-water ditches with an additional 9 sites serving as controls. Sites where fish were introduced required no Bacillus sphaericus (VectoLex) treatments during the 10-week experiment. The control sites required 19 VectoLex treatments during the same 10-week time span. Survival analysis revealed a statistically significant difference in time to first VectoLex treatment between fish sites and control sites. Our results suggest fathead minnows may provide a long-lasting and ecologically and economically feasible alternative to the use of VectoLex for Culex larval control.

  15. Evaluation of immature mosquitocidal properties ofXanthium strumarium Linn. plant extracts against Culex mosquitoes (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Kasim Roba; Getinet Masresha; Wondmeneh Jemberie; Raja Nagappan

    2015-01-01

    Objective:To evaluate immature mosquitocidal properties ofXanthium strumarium plant extracts againstCulex 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 ofCulex 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 againstCulex mosquitoes. The aqueous leaf extract can be used by applying on small man-made breeding places to prevent adult emergence.

  16. Laboratory and Field Evaluations of Mosquiron® 0.12CRD, a New Formulation of Novaluron, Against Culex Mosquitoes.

    Science.gov (United States)

    Su, Tianyun; Cheng, Min-Lee; Melgoza, Alfonso; Thieme, Jennifer

    2014-12-01

    Laboratory and field evaluations were conducted to assess the activity and efficacy of Mosquiron® 0.12CRD, a new formulation containing 0.12% novaluron, against immature Culex mosquitoes. In laboratory bioassays, this formulation was highly active against Culex quinquefasciatus as indicated by low inhibition of emergence (IE) values (IE50 and IE90). When Mosquiron 0.12CRD was applied at 1 briquet per underground stormwater vault, counts of late instars showed a significant reduction on day 28 posttreatment. When the late instars and pupae collected from Mosquiron-treated water were brought back to the laboratory for posttreatment observation, emergence inhibition was >90% on day 7. When the late instars from a laboratory colony of Cx. quinquefasciatus were exposed to the Mosquiron-treated water, 99% and 95% emergence inhibition was noted on day 7 and day 14, respectively. When Mosquiron 0.12CRD was applied at 11 briquets per vault, significant reductions of larval populations were encountered on days 7 and 35 posttreatment for early instars, and on days 14, 21, and 35 posttreatment for late instars. Laboratory observation of late instars and pupae sampled from the treated vault water showed nearly complete emergence inhibition from day 7 to day 28 posttreatment. A similar trend was observed in laboratory-reared late instars of Cx. quinquefasciatus when exposed to the treated water. Preliminary evaluations indicated that Mosquiron 0.12CRD is a useful new tool to control Culex mosquitoes breeding in persistent sources.

  17. [Sensitivity and specificity of prick skin test with two concentrations of standardized extract of Culex quinquefasciatus in allergic children].

    Science.gov (United States)

    Castro-Almarales, Raúl Lázaro; Álvarez-Castelló, Mirta; Ronquillo-Díaz, Mercedes; Rodríguez-Canosa, José S; González-León, Mayda; Navarro-Viltre, Bárbara I; Betancourt-Mesia, Daniel; Enríquez-Domínguez, Irene; Reyes-Zamora, Mary Carmen; Oliva-Díaz, Yunia; Mateo-Morejón, Maytee; Labrada-Rosado, Alexis

    2016-01-01

    Antecedentes: las opciones diagnósticas de las reacciones inmunológicas a la picadura del mosquito son limitadas. En Cuba, las reacciones mediadas por IgE más frecuentes son por picadura de Culex quinquefasciatus. Objetivo: determinar la sensibilidad y especificidad de la prueba cutánea por punción con dos dosis del extracto estandarizado en unidades de nitrógeno proteico (UNP) de Culex quinquefasciatus (BIOCEN, Cuba). Material y método: estudio analítico efectuado en 100 niños entre 2 y 15 años de edad: 50 pacientes atópicos con antecedentes de alergia a la picadura de mosquito e IgE sérica específica positiva a Culex quinquefasciatus y 50 pacientes atópicos sin antecedentes de alergia a la picadura de mosquito e IgE sérica específica negativa a Culex quinquefasciatus. La prueba cutánea por punción se realizó por duplicado en los antebrazos de los pacientes. Las dosis investigadas fueron 100 y 10 UNP/mL. Resultados: en la prueba cutánea por punción con el extracto de mayor concentración se obtuvo un tamaño del área del habón de 22.09 mm2 y con la menor concentración de 8.19 mm2; una diferencia estadísticamente significativa (p=0.001, prueba t de Student). La prueba cutánea positiva se correlacionó en el 100% de los pacientes con la existencia de IgE específica. La prueba con ambas dosis mostró 94% de especificidad y 88% de sensibilidad. Conclusión: la alta coincidencia en el resultado de la prueba cutánea nos muestra que puede sustituirse la concentración del extracto a 100 UNP/mL por la de menor concentración, sin perder confiabilidad en el diagnóstico de sensibilización al mosquito Culex quinquefasciatus, utilizando ese método in vivo.

  18. Aspectos ecológicos de Anopheles cruzii e Culex ribeirensis (Diptera, Culicidae da Mata Atlântica de Morretes, Paraná, Brasil Ecological aspects of Anopheles cruzii and Culex ribeirensis (Diptera, Culicidae in Atlantic Forest of Morretes, Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Luiz Gonzaga dos Santos-Neto

    2008-01-01

    Full Text Available Um estudo foi realizado sobre mosquitos adultos de abril 1995 a março 1996 na Mata Atlântica do município de Morretes, Paraná, Brasil. A investigação foi procedida com auxílio de duas armadilhas luminosas CDC-M instaladas em estratos verticais diferentes. Os mosquitos foram capturados mensalmente durante um ano, com início às 18 horas e término às 6 horas do dia seguinte, totalizando 144 horas de trabalho de campo. Obteve-se 1.408 exemplares de mosquitos (409 na copa e 999 próximo ao solo, pertencentes a 10 gêneros e 31 espécies. Anopheles cruzii e Culex ribeirensis foram predominantes e são objetos do presente estudo. Não foi observada diferença entre as armadilhas para Anopheles cruzii. Mas Culex ribeirensis foi coletado em maior número pela CDC-M/solo. Anopheles cruzii, quanto à freqüência horária, apresentou picos nas primeiras horas da noite, depois a sua atividade decresceu progressivamente até o crepúsculo matutino, sem apresentar um pico secundário. Em referência a distribuição mensal, Anopheles cruzii foi mais freqüente nos meses de abril e maio de 1995 e março de 1996. Não houve correlação do número de exemplares com a temperatura ou precipitações pluviométricas. Culex ribeirensis apresentou maior atividade de vôo de 22h às 4h, mas não houve picos significativos. Nas coletas obtidas por mês, Culex ribeirensis teve picos em dezembro e janeiro. Houve correlação do número de espécimes deste culicíneo com a temperatura e precipitações pluviométricas. Constituem os primeiros registros para o Estado do Paraná: Ochlerotatus rhyacophilus, Culex misionensis, Culex pedroi, Culex ribeirensis e Culex zeteki.A study of adult mosquitoes was performed from April 1995 to March 1996 in the Atlantic Forest near to Morretes city, Paraná, Brazil. The research was carried out by using two CDC-M light traps installed in different vertical stratification levels. Mosquitoes were collected monthly throughout

  19. Midgut barrier imparts selective resistance to filarial worm infection in Culex pipiens pipiens.

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    Michelle L Michalski

    Full Text Available Mosquitoes in the Culex pipiens complex thrive in temperate and tropical regions worldwide, and serve as efficient vectors of Bancroftian lymphatic filariasis (LF caused by Wuchereria bancrofti in Asia, Africa, the West Indies, South America, and Micronesia. However, members of this mosquito complex do not act as natural vectors for Brugian LF caused by Brugia malayi, or for the cat parasite B. pahangi, despite their presence in South Asia where these parasites are endemic. Previous work with the Iowa strain of Culex pipiens pipiens demonstrates that it is equally susceptible to W. bancrofti as is the natural Cx. p. pipiens vector in the Nile Delta, however it is refractory to infection with Brugia spp. Here we report that the infectivity barrier for Brugia spp. in Cx. p. pipiens is the mosquito midgut, which inflicts internal and lethal damage to ingested microfilariae. Following per os Brugia exposures, the prevalence of infection is significantly lower in Cx. p. pipiens compared to susceptible mosquito controls, and differs between parasite species with <50% and <5% of Cx. p. pipiens becoming infected with B. pahangi and B. malayi, respectively. When Brugia spp. mf were inoculated intrathoracically to bypass the midgut, larvae developed equally well as in controls, indicating that, beyond the midgut, Cx. p. pipiens is physiologically compatible with Brugia spp. Mf isolated from Cx. p. pipiens midguts exhibited compromised motility, and unlike mf derived from blood or isolated from the midguts of Ae. aegypti, failed to develop when inoculated intrathoracically into susceptible mosquitoes. Together these data strongly support the role of the midgut as the primary infection barrier for Brugia spp. in Cx. p. pipiens. Examination of parasites recovered from the Cx. p. pipiens midgut by vital staining, and those exsheathed with papain, suggest that the damage inflicted by the midgut is subcuticular and disrupts internal tissues. Microscopic studies

  20. Native Argentinean cyclopoids (Crustacea: Copepoda as predators of Aedes aegypti and Culex pipiens (Diptera: Culicidae mosquitoes

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    María C Tranchida

    2009-12-01

    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

  1. Culex tarsalis vitellogenin gene promoters investigated in silico and in vivo using transgenic Drosophila melanogaster.

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    Song Chen

    Full Text Available INTRODUCTION: Genetic modification, or transgenesis, is a powerful technique to investigate the molecular interactions between vector-borne pathogens and their arthropod hosts, as well as a potential novel approach for vector-borne disease control. Transgenesis requires the use of specific regulatory regions, or promoters, to drive expression of genes of interest in desired target tissues. In mosquitoes, the vast majority of described promoters are from Anopheles and Aedes mosquitoes. RESULTS: Culex tarsalis is one of the most important vectors of arboviruses (including West Nile virus in North America, yet it has not been the subject of molecular genetic study. In order to facilitate molecular genetic work in this important vector species, we isolated four fat body-specific promoter sequences located upstream of the Cx. tarsalis vitellogenin genes (Vg1a, Vg1b, Vg2a and Vg2b. Sequences were analyzed in silico to identify requisite cis-acting elements. The ability for promoter sequences to drive expression of green fluorescent protein (GFP in vivo was investigated using transgenic Drosophila melanogaster. All four promoters were able to drive GFP expression but there was dramatic variation between promoters and between individual Drosophila lines, indicating significant position effects. The highest expression was observed in line Vg2bL3, which was >300-fold higher than the lowest line Vg1aL2. CONCLUSIONS: These new promoters will be useful for driving expression of genes of interest in transgenic Cx. tarsalis and perhaps other insects.

  2. Solid-state NMR reveals differential carbohydrate utilization in diapausing Culex pipiens

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    Chang, James; Singh, Jugeshwar; Kim, Sungshil; Hockaday, William C.; Sim, Cheolho; Kim, Sung Joon

    2016-11-01

    Culex pipiens is the mosquito that vectors West Nile Virus and other human-pathogenic flavivruses in North America. In response to shortened day length and lower temperatures, female Cx. pipiense prepares for the diapause by actively feeding on carbohydrates to increase the biosynthesis of glycogen and lipid to store energy for overwintering. The effect of feeding different carbohydrates on glycogen and lipid biosynthesis in diapausing mosquitoes was investigated in vivo using 13C solid-state NMR. Diapause-destined adult females and nondiapausing counterparts after adult eclosion were fed with three different carbohydrate sources for 7 days: 1) 10% sucrose, 2) 10% D-[13C6]glucose, and 3) 1% D-[13C6]glucose co-provisioned with 10% sucrose. NMR measurements show that sucrose and glucose are metabolized differently in diapausing mosquitoes. Mosquitoes fed on sucrose primarily accumulate glycogen with increased branching structures, but less of lipids. In contrast, mosquitoes fed exclusively on glucose show accumulation of both glycogen and lipid with increased aliphatic chain length. Glucose is exclusively metabolized for the biosynthesis of triacylglyceride when mosquitoes were co-fed with sucrose. Our findings provide novel insights into the insect carbohydrate metabolism that governs glycogen and lipid biosynthesis during diapause, which is fundamental for the insect survival during inimical environments.

  3. West Nile virus genetic diversity is maintained during transmission by Culex pipiens quinquefasciatus mosquitoes.

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    Doug E Brackney

    Full Text Available Due to error-prone replication, RNA viruses exist within hosts as a heterogeneous population of non-identical, but related viral variants. These populations may undergo bottlenecks during transmission that stochastically reduce variability leading to fitness declines. Such bottlenecks have been documented for several single-host RNA viruses, but their role in the population biology of obligate two-host viruses such as arthropod-borne viruses (arboviruses in vivo is unclear, but of central importance in understanding arbovirus persistence and emergence. Therefore, we tracked the composition of West Nile virus (WNV; Flaviviridae, Flavivirus populations during infection of the vector mosquito, Culex pipiens quinquefasciatus to determine whether WNV populations undergo bottlenecks during transmission by this host. Quantitative, qualitative and phylogenetic analyses of WNV sequences in mosquito midguts, hemolymph and saliva failed to document reductions in genetic diversity during mosquito infection. Further, migration analysis of individual viral variants revealed that while there was some evidence of compartmentalization, anatomical barriers do not impose genetic bottlenecks on WNV populations. Together, these data suggest that the complexity of WNV populations are not significantly diminished during the extrinsic incubation period of mosquitoes.

  4. The potential of cladocerans as controphic competitors of the mosquito Culex pipiens.

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    Duquesne, Sabine; Kroeger, Iris; Kutyniok, Magdalene; Liess, Matthias

    2011-05-01

    This study assesses the potential of cladocerans as competitors for controlling the oviposition and larval abundances of mosquitoes. Control of mosquito larvae involving the use of antagonists has focused mostly on predators. We hypothesized that cladoceran competitors have a strong potential to control larval populations of some species of mosquitoes that can be early colonizers of newly-filled waterbodies, and should be less efficient competitors. To test this hypothesis, the establishment and development of larval populations of wild Culex pipiens were investigated in outdoor microcosms varying in terms of Daphnia magna populations. When the population was well established (i.e., high densities of D. magna), oviposition was fully inhibited and there was consequently no mosquito larvae. When the population was more recently established (i.e., lower densities of D. magna), oviposition and larval development of Cx. pipiens occurred. In the absence of D. magna, oviposition, larval biomass, and abundance of Cx. pipiens reached high values. In this situation, conspecifics were inhibiting further oviposition of Cx. pipiens. Based on these results, we suggest that competing zooplankton species, such as D. magna, could be used for the control of mosquito species such as Cx. pipiens. This approach could be beneficial for the management of wetlands.

  5. Toxicity of 25 synthetic insecticides to the field population of Culex quinquefasciatus Say.

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    Shah, Rizwan Mustafa; Alam, Mahbob; Ahmad, Daniyal; Waqas, Muhammad; Ali, Qasim; Binyamin, Muhammad; Shad, Sarfraz Ali

    2016-11-01

    The Culex quinquefaciatus Say, commonly known as the southern house mosquito, is well known for biting nuisance and vectoring of some fatal diseases. Synthetic chemicals have been relied upon as the major control measure to control mosquitoes. Therefore, we have evaluated 21 insecticides belonging to different chemical classes for their toxicity to C. quinquefaciatus females. Chlorfenapyr was the most toxic adulticide among all the tested insecticides. Among pyrethroids, deltamethrin was the least toxic adulticide, and all other have same toxicity. In case of organophosphates, the chlorpyrifos was the most toxic insecticide. Neonicotinoids such as acetamiprid, nitenpyram, and clothianidin have similar toxicity based on overlapping of 95 % confidence intervals (CI) and were more toxic when compared with the imidacloprid. The spinetoram was more toxic as compared with the spinosad (based on non-overlapping 95 % Cl). In case of ketoenoles, spirotetrament was more toxic as compared with the spiromesifen. Emamectin benzoate was the most toxic insecticide when compared with fipronil and indoxacarb. We also have tested four insect growth regulators (IGRS) including lufenuron, methoxyfenozide, pyriproxyfen, and cyromazine as larvicides. The lufenuron and pyriproxyfen have similar toxicity based upon their overlapping 95 % CI and were more toxic as compared with the methoxyfenozide and cyromazine. The methoxyfenozide was the moderately toxic among all the tested IGRS, and cyromazine was the least toxic among all the tested IGRS. These results will prove helpful in effectuating an effective integrated vector management program for C. quinquefaciatus.

  6. Control of pyrethroid-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes with chlorfenapyr in Benin.

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    N'Guessan, Raphael; Boko, Pelagie; Odjo, Abiba; Knols, Bart; Akogbeto, Martin; Rowland, Mark

    2009-04-01

    To compare the efficacy of chlorfenapyr applied on mosquito nets and as an indoor residual spray against populations of Anopheles gambiae and Culex quinquefasciatus in an area of Benin that shows problematic levels of pyrethroid resistance. Eight-week trial conducted in experimental huts. Indoor residual spraying killed 82.9% of An. gambiae overall (mean mortality: 79.5%) compared to 53.5% overall (mean mortality: 61.7%) in the hut containing the lower dosed ITN. Analysis of data on a fortnightly basis showed high levels of mosquito mortality and blood-feeding inhibition during the first few weeks after treatment. Control of C. quinquefasciatus by the IRS and ITN interventions showed a similar trend to that of An. gambiae and though the average level of mortality was lower it was still much higher than with pyrethroid treatments against this population. Chlorfenapyr's reputation for being rather slow acting was evident particularly at lower dosages. The treatments showed no evidence of excito-repellent activity in this trial. Chlorfenapyr has the potential to control pyrethroid resistant populations of A. gambiae. There is a need to develop long-lasting formulations of chlorfenapyr to prolong its residual life on nets and sprayed surfaces. On nets it could be combined with a contact irritant pyrethroid to give improved protection against mosquito biting while killing pyrethroid-resistant mosquitoes that come into contact with the net.

  7. Effect of chlorfenapyr on cypermethrin-resistant Culex pipiens pallens Coq mosquitoes.

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    Yuan, J Z; Li, Q F; Huang, J B; Gao, J F

    2015-03-01

    Chlorfenapyr is a promising pyrrole insecticide with a unique mechanism of action that does not confer cross-resistance to neurotoxic insecticides. The effect of chlorfenapyr on pyrethorid-resistant Culex pipiens pallens Coq (Diptera: Culicidae) has not been fully investigated under laboratory conditions. In this study, cypermethrin-resistant C. p. pallens exhibited 376.79-fold and 395.40-fold increase in resistance to cypermethrin compared with susceptible strains after exposure for 24 and 48h, respectively. Larvae and adults were tested for susceptibility using dipping, topical, and impregnated paper methods as recommended by the WHO. No cross-resistance to chlorfenapyr was found. Increased mortality was apparent between 48 and 72h, indicating a slow rate of toxic activity. Synergism experiments with piperonyl butoxide (PBO) showed an antagonistic effect on chlorfenapyr toxicity. Mixtures of chlorfenapyr and cypermethrin could therefore provide additional benefits over either insecticide used alone. Mixtures of 5ng/ml chlorfenapyr and 500ng/ml cypermethrin exhibited a slight synergistic effect on cypermethrin-resistant mosquitoes (3.33, 6.84 and 2.34% after 24, 48 and 72h exposure, respectively. This activity was lost when the chlorfenapyr concentration was increased to 10 or 20ng/ml. Chlorfenapyr showed quite good results for pyrethroid-resistant C. p. pallens, and could improve public health by reducing the occurrence of mosquito bites and subsequently protecting against transmission of lymphatic filariasis and Japanese encephalitis. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Neem oil (Azadirachta indica) nanoemulsion--a potent larvicidal agent against Culex quinquefasciatus.

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    Anjali, C H; Sharma, Yamini; Mukherjee, Amitava; Chandrasekaran, Natarajan

    2012-02-01

    Nanoemulsion composed of neem oil and non-ionic surfactant Tween 20, with a mean droplet size ranging from 31.03 to 251.43 nm, was formulated for various concentrations of the oil and surfactant. The larvicidal effect of the formulated neem oil nanoemulsion was checked against Culex quinquefasciatus. O/W emulsion was prepared using neem oil, Tween 20 and water. Nanoemulsion of 31.03 nm size was obtained at a 1:3 ratio of oil and surfactant, and it was found to be stable. The larger droplet size (251.43 nm) shifted to a smaller size of 31.03 nm with increase in the concentration of Tween 20. The viscosity of the nanoemulsion increased with increasing concentration of Tween 20. The lethal concentration (LC50) of the nanoemulsion against Cx. quinquefasciatus was checked for 1:0.30, 1:1.5 and 1:3 ratios of oil and surfactant respectively. The LC50 decreased with droplet size. The LC50 for the ratio 1:3 nanoemulsions was 11.75 mg L(-1). The formulated nanoemulsion of 31.03 nm size was found to be an effective larvicidal agent. This is the first time that a neem oil nanoemulsion of this droplet size has been reported. It may be a good choice as a potent and selective larvicide for Cx. quinquefasciatus. Copyright © 2011 Society of Chemical Industry.

  9. Culex pipiens forms and urbanization: effects on blood feeding sources and transmission of avian Plasmodium.

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    Martínez-de la Puente, Josué; Ferraguti, Martina; Ruiz, Santiago; Roiz, David; Soriguer, Ramón C; Figuerola, Jordi

    2016-12-08

    The wide spread mosquito Culex pipiens pipiens have two forms molestus and pipiens which frequently hybridize. The two forms have behavioural and physiological differences affecting habitat requirements and host selection, which may affect the transmission dynamic of Cx. p. pipiens-borne diseases. During 2013, blood engorged Cx. p. pipiens mosquitoes were captured in urban, rural and natural areas from Southern Spain. In 120 mosquitoes, we identified the blood meal origin at vertebrate species/genus level and the mosquito form. The presence and molecular lineage identity of avian malaria parasites in the head-thorax of each mosquito was also analysed. Mosquitoes of the form pipiens were more frequently found in natural than in urban areas. The proportion of Cx. pipiens form molestus and hybrids of the two forms did not differ between habitat categories. Any significant difference in the proportion of blood meals on birds between forms was found. Birds were the most common feeding source for the two forms and their hybrids. Among mammals, dogs and humans were the most common hosts. Two Plasmodium and one Haemoproteus lineages were found in mosquitoes, with non-significant differences between forms. This study supports a differential distribution of Cx. p. pipiens form pipiens between urban and natural areas. Probably due to the similar feeding sources of both mosquito forms and their hybrids here, all of them may frequently interact with avian malaria parasites playing a role in the transmission of Plasmodium.

  10. Diel biting activity of Culex (Melanoconion) caudelli in Trinidad, West Indies.

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    Chadee, D D; Tikasingh, E S

    1989-07-01

    The diel biting periodicity of the arbovirus vector Culex (Melanoconion) caudelli Dyar and Knab (Diptera; Culicidae) in the Aripo-Wallerfield forest, Trinidad, was studied by collecting mosquitoes attracted to mouse-baited traps at 2-hourly intervals during eight 24 h periods. Biting females of Cx caudelli were collected during all night-time hours, 18.00-06.00 hours, with an overall unimodal pattern, i.e. one well-defined peak between 22.00 and 04.00 hours. This contrasts with previous reports that Cx caudelli is diurnally active. During the four moon phases, the period of peak biting activity varied from 22.00 to 24.00 hours at fullmoon, from 22.00 to 04.00 hours at first quarter, and from 24.00 to 02.00 hours at new moon and last quarter phases. The number of mosquitoes collected varied significantly with moon phases, the highest (152/24 h) being collected in the first lunar quarter and the lowest (71/24 h) in the last lunar quarter. Cloud cover and rainfall had no significant effect on the diel biting periodicity of Cx caudelli.

  11. A rapid knockdown effect of Penicillium citrinum for control of the mosquito Culex quinquefasciatus in Thailand.

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    Maketon, Monchan; Amnuaykanjanasin, Alongkorn; Kaysorngup, Achirayar

    2014-02-01

    Twenty local isolates of entomopathogenic fungi were determined for control of the larvae and adults of Culex quinquefasciatus. In a laboratory experiment, a Penicillium sp. CM-010 caused 100% mortality of third-instar larvae within 2 h using a conidial suspension of 1 × 10⁶ conidia ml⁻¹. Its LC₅₀ was 3 × 10⁵ conidia ml⁻¹, and the lethal time (LT₅₀) was 1.06 h. Cloning and sequencing of its internal transcribed spacer region indicated that this Penicillium species is Penicillium citrinum (100% identity in 434 bp). Mortality of the adult was highest with Aspergillus flavus CM-011 followed with Metarhizium anisopliae CKM-048 from 1 × 10⁹ conidia ml⁻¹. P. citrinum CM-010 at 1 × 10⁶ conidia ml⁻¹ killed 100% larvae within 2 h while Bacillus thuringiensis var. israelensis at 5 ITU ml⁻¹ required 24 h. This P. citrinum CM-010 also greatly reduced survival of C. quinquefasciatus larvae in an unreplicated field test. Light and transmission electron micrographs showed that the fungal conidia were ingested by the larvae and deposited in the gut. The metabolite patulin was produced by P. citrinum CM-010 instead of citrinin.

  12. Molecular ecological analysis of planktonic bacterial communities in constructed wetlands invaded by Culex (Diptera: Culicidae) mosquitoes.

    Science.gov (United States)

    Popko, David A; Han, Suk-Kyun; Lanoil, Brian; Walton, William E

    2006-11-01

    The succession of the planktonic bacterial community during the colonization by Culex (Diptera: Culicidae) mosquitoes of 0.1-ha treatment wetlands was studied using denaturing gradient gel electrophoresis (DGGE) methodology. Relationships between apparent bacterial diversity and ecological factors (water quality, total bacterial counts, and immature mosquito abundance) were determined during a 1-mo flooding period. Analysis of DGGE banding patterns indicated that days postflooding and temporal changes in water quality were the primary and secondary determinants, respectively, of diversity in bacterial communities. Lower levels of diversity were associated with later postflood stages and increases in ammoniacal nitrogen concentration and total bacterial counts. Diversity was therefore most similar for bacteria present on the same sampling date at wetland locations with similar flooding regimes and water quality, suggesting that wastewater input was the driving force shaping bacterial communities. Comparatively small changes in bacterial diversity were connected to natural processes as water flowed through the wetlands. Greater immature mosquito abundance coincided with less diverse communities composed of greater total numbers of bacteria. Five individual DGGE bands were directly associated with fluctuations in mosquito production, and an additional 16 bands were associated with hydrological aspects of the environment during the rise and fall of mosquito populations. A marked decline in mosquito numbers 21 d after inundation may have masked associations of bacterial communities and mosquito recruitment into the sparsely vegetated wetlands. DGGE was an effective tool for the characterization of bacteria in mosquito habitat in our study, and its potential application in mosquito ecology is discussed.

  13. Cytonuclear Epistasis Controls the Density of Symbiont Wolbachia pipientis in Nongonadal Tissues of Mosquito Culex quinquefasciatus.

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    Emerson, Kevin J; Glaser, Robert L

    2017-08-07

    Wolbachia pipientis, a bacterial symbiont infecting arthropods and nematodes, is vertically transmitted through the female germline and manipulates its host's reproduction to favor infected females. Wolbachia also infects somatic tissues where it can cause nonreproductive phenotypes in its host, including resistance to viral pathogens. Wolbachia-mediated phenotypes are strongly associated with the density of Wolbachia in host tissues. Little is known, however, about how Wolbachia density is regulated in native or heterologous hosts. Here, we measure the broad-sense heritability of Wolbachia density among families in field populations of the mosquito Culex pipiens, and show that densities in ovary and nongonadal tissues of females in the same family are not correlated, suggesting that Wolbachia density is determined by distinct mechanisms in the two tissues. Using introgression analysis between two different strains of the closely related species C. quinquefasciatus, we show that Wolbachia densities in ovary tissues are determined primarily by cytoplasmic genotype, while densities in nongonadal tissues are determined by both cytoplasmic and nuclear genotypes and their epistatic interactions. Quantitative-trait-locus mapping identified two major-effect quantitative-trait loci in the C. quinquefasciatus genome explaining a combined 23% of variance in Wolbachia density, specifically in nongonadal tissues. A better understanding of how Wolbachia density is regulated will provide insights into how Wolbachia density can vary spatiotemporally in insect populations, leading to changes in Wolbachia-mediated phenotypes such as viral pathogen resistance. Copyright © 2017 Emerson, Glaser.

  14. Modeling the distribution of Culex tritaeniorhynchus to predict Japanese encephalitis distribution in the Republic of Korea

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    Penny Masuoka

    2010-11-01

    Full Text Available Over 35,000 cases of Japanese encephalitis (JE are reported worldwide each year. Culex tritaeniorhynchus is the primary vector of the JE virus, while wading birds are natural reservoirs and swine amplifying hosts. As part of a JE risk analysis, the ecological niche modeling programme, Maxent, was used to develop a predictive model for the distribution of Cx. tritaeniorhynchus in the Republic of Korea, using mosquito collection data, temperature, precipitation, elevation, land cover and the normalized difference vegetation index (NDVI. The resulting probability maps from the model were consistent with the known environmental limitations of the mosquito with low probabilities predicted for forest covered mountains. July minimum temperature and land cover were the most important variables in the model. Elevation, summer NDVI (July-September, precipitation in July, summer minimum temperature (May-August and maximum temperature for fall and winter months also contributed to the model. Comparison of the Cx. tritaeniorhynchus model to the distribution of JE cases in the Republic of Korea from 2001 to 2009 showed that cases among a highly vaccinated Korean population were located in high-probability areas for Cx. tritaeniorhynchus. No recent JE cases were reported from the eastern coastline, where higher probabilities of mosquitoes were predicted, but where only small numbers of pigs are raised. The geographical distribution of reported JE cases corresponded closely with the predicted high-probability areas for Cx. tritaeniorhynchus, making the map a useful tool for health risk analysis that could be used for planning preventive public health measures.

  15. Mitochondrial DNA analyses reveal low genetic diversity in Culex quinquefasciatus from residential areas in Malaysia.

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    Low, V L; Lim, P E; Chen, C D; Lim, Y A L; Tan, T K; Norma-Rashid, Y; Lee, H L; Sofian-Azirun, M

    2014-06-01

    The present study explored the intraspecific genetic diversity, dispersal patterns and phylogeographic relationships of Culex quinquefasciatus Say (Diptera: Culicidae) in Malaysia using reference data available in GenBank in order to reveal this species' phylogenetic relationships. A statistical parsimony network of 70 taxa aligned as 624 characters of the cytochrome c oxidase subunit I (COI) gene and 685 characters of the cytochrome c oxidase subunit II (COII) gene revealed three haplotypes (A1-A3) and four haplotypes (B1-B4), respectively. The concatenated sequences of both COI and COII genes with a total of 1309 characters revealed seven haplotypes (AB1-AB7). Analysis using tcs indicated that haplotype AB1 was the common ancestor and the most widespread haplotype in Malaysia. The genetic distance based on concatenated sequences of both COI and COII genes ranged from 0.00076 to 0.00229. Sequence alignment of Cx. quinquefasciatus from Malaysia and other countries revealed four haplotypes (AA1-AA4) by the COI gene and nine haplotypes (BB1-BB9) by the COII gene. Phylogenetic analyses demonstrated that Malaysian Cx. quinquefasciatus share the same genetic lineage as East African and Asian Cx. quinquefasciatus. This study has inferred the genetic lineages, dispersal patterns and hypothetical ancestral genotypes of Cx. quinquefasciatus.

  16. Suppression of allatotropin simulates reproductive diapause in the mosquito Culex pipiens.

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    Kang, David S; Denlinger, David L; Sim, Cheolho

    2014-05-01

    The cessation of juvenile hormone (JH) production is a key endocrine event that halts ovarian development and hence initiates diapause in females of the mosquito, Culex pipiens. The shutdown in endocrine activity of the corpora allata (CA), the source of JH, was manifested in the smaller size of CA in females reared under short daylengths (diapause) compared to those reared under long daylengths (nondiapause), as well as in low expression of the mRNA encoding allatotropin, the neuropeptide that promotes JH biosynthesis in the CA. Genes encoding both allatotropin and allatostatin were identified in C. pipiens, but only expression levels of allatotropin differed in the two types of females. Knockdown of allatotropin mRNA using RNA interference in females programmed for nondiapause resulted in a cessation of ovarian development akin to diapause. This arrest in development could be reversed with an application of JH. Our results thus suggest that suppression of allatotropin is a critical link in regulating the shutdown of the CA during diapause.

  17. Insulin signaling and FOXO regulate the overwintering diapause of the mosquito Culex pipiens.

    Science.gov (United States)

    Sim, Cheolho; Denlinger, David L

    2008-05-06

    The short day lengths of late summer program the mosquito Culex pipiens to enter a reproductive diapause characterized by an arrest in ovarian development and the sequestration of huge fat reserves. We suggest that insulin signaling and FOXO (forkhead transcription factor), a downstream molecule in the insulin signaling pathway, mediate the diapause response. When we used RNAi to knock down expression of the insulin receptor in nondiapausing mosquitoes (those reared under long day lengths) the primary follicles were arrested in a stage comparable to diapause. The mosquitoes could be rescued from this developmental arrest with an application of juvenile hormone, an endocrine trigger known to terminate diapause in this species. When dsRNA directed against FOXO was injected into mosquitoes programmed for diapause (reared under short day lengths) fat storage was dramatically reduced and the mosquito's lifespan was shortened, results suggesting that a shutdown of insulin signaling prompts activation of the downstream gene FOXO, leading to the diapause phenotype. Thus, the results are consistent with a role for insulin signaling in the short-day response that ultimately leads to a cessation of juvenile hormone production. The similarity of this response to that observed in the diapause of Drosophila melanogaster and in dauer formation of Caenorhabditis elegans suggests a conserved mechanism regulating dormancy in insects and nematodes.

  18. Isolation and identification of α-proteobacteria from Culex pipiens (Diptera Culicidae) larvae.

    Science.gov (United States)

    Tranchida, M C; Riccillo, P M; Rodriguero, M S; García, J J; Micieli, M V

    2012-01-01

    A survey of drainage ditches in suburban areas of La Plata, Buenos Aires province, Argentina for pathogens of Culex pipiens larvae was conducted from 2003 to 2006. C. pipiens larvae of opaque, white color were found in several of those field collections. When the white larvae were dissected and observed by phase-contrast microscopy in wet-mount preparations, the presence of bacteria, located in the hemocoel, was recorded. Laboratory experiments were performed to elucidate the pathway for transmission of this pathogen. Although approaches involving traditional culturing had failed to reveal the identity of the new microorganism present, molecular techniques to identify the pathogen in the studies reported here were successful. The partial sequence of the 16S-rRNA gene constitutes a powerful tool for the detection of new isolates from the hemocoele of C. pipiens larvae. These bacteria were characterized as belonging to the genus Novispirillum. In spite of the genus's wide distribution in different aquatic environments, information related to the parasitic relationship of Novispirillum spp. to aquatic insects is scarce, and this association has not been described in other mosquito species. This report constitutes the first documentation of Novispirillum spp. as a pathogen for mosquito larvae. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Development of Resistance to Pyrethroid in Culex pipiens pallens Population under Different Insecticide Selection Pressures.

    Science.gov (United States)

    Shi, Linna; Hu, Hongxia; Ma, Kai; Zhou, Dan; Yu, Jing; Zhong, Daibin; Fang, Fujin; Chang, Xuelian; Hu, Shengli; Zou, Feifei; Wang, Weijie; Sun, Yan; Shen, Bo; Zhang, Donghui; Ma, Lei; Zhou, Guofa; Yan, Guiyun; Zhu, Changliang

    2015-01-01

    Current vector control programs are largely dependent on pyrethroids, which are the most commonly used and only insecticides recommended by the World Health Organization for insecticide-treated nets (ITNs). However, the rapid spread of pyrethroid resistance worldwide compromises the effectiveness of control programs and threatens public health. Since few new insecticide classes for vector control are anticipated, limiting the development of resistance is crucial for prolonging efficacy of pyrethroids. In this study, we exposed a field-collected population of Culex pipiens pallens to different insecticide selection intensities to dynamically monitor the development of resistance. Moreover, we detected kdr mutations and three detoxification enzyme activities in order to explore the evolutionary mechanism of pyrethroid resistance. Our results revealed that the level of pyrethroid resistance was proportional to the insecticide selection pressure. The kdr and metabolic resistance both contributed to pyrethroid resistance in the Cx. pipiens pallens populations, but they had different roles under different selection pressures. We have provided important evidence for better understanding of the development and mechanisms of pyrethroid resistance which may guide future insecticide use and vector management in order to avoid or delay resistance.

  20. Differential Infectivities among Different Japanese Encephalitis Virus Genotypes in Culex quinquefasciatus Mosquitoes.

    Science.gov (United States)

    Huang, Yan-Jang S; Hettenbach, Susan M; Park, So Lee; Higgs, Stephen; Barrett, Alan D T; Hsu, Wei-Wen; Harbin, Julie N; Cohnstaedt, Lee W; Vanlandingham, Dana L

    2016-10-01

    During the last 20 years, the epidemiology of Japanese encephalitis virus (JEV) has changed significantly in its endemic regions due to the gradual displacement of the previously dominant genotype III (GIII) with clade b of GI (GI-b). Whilst there is only limited genetic difference distinguishing the two GI clades (GI-a and GI-b), GI-b has shown a significantly wider and more rapid dispersal pattern in several regions in Asia than the GI-a clade, which remains restricted in its geographic distribution since its emergence. Although previously published molecular epidemiological evidence has shown distinct phylodynamic patterns, characterization of the two GI clades has only been limited to in vitro studies. In this study, Culex quinquefasciatus, a known competent JEV mosquito vector species, was orally challenged with three JEV strains each representing GI-a, GI-b, and GIII, respectively. Infection and dissemination were determined based on the detection of infectious viruses in homogenized mosquitoes. Detection of JEV RNA in mosquito saliva at 14 days post infection indicated that Cx. quinquefasciatus can be a competent vector species for both GI and GIII strains. Significantly higher infection rates in mosquitoes exposed to the GI-b and GIII strains than the GI-a strain suggest infectivity in arthropod vectors may lead to the selective advantage of previously and currently dominant genotypes. It could thus play a role in enzootic transmission cycles for the maintenance of JEV if this virus were ever to be introduced into North America.

  1. Bacillus thuringiensis isolates entomopathogenic for Culex quinquefasciatus (Diptera: Culicidae and Anticarsia gemmatalis (Lepidoptera: Noctuidae

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    V. Gobatto

    Full Text Available Samples of the Bacillus thuringiensis (Bt were collected from soil and insects. Eight isolates were selected from rural soil, 15 from urban soil and 11 from insects. These were evaluated for entomopathogenicity against larvae of Anticarsia gemmatalis and Culex quinquefasciatus. The pathogenicity tests showed that a higher percentage of isolates were active against A. gemmatalis (60% compared to C. quinquefasciatus (31%. Probit analysis (LC50 indicated that against A. gemmatalis four of the isolates presented values similar to the reference strain against A. gemmatalis, while against C. quinquefasciatus one isolate showed an LC50 similar to the reference strain (IPS-82. SDS-PAGE characterisation of two isolates showed a 27 kDa protein fraction related to the Bt subspecies israelensis cytolytic toxin (cyt gene. One 130 kDa protein, possibly related to the Bt crystal inclusions (cry1 gene, was identified in the other two isolates, which were more toxic for lepidoptera; another isolate presented a protein of 100 kDa. Some new local Bt isolates had similar LC50 probit values to the reference strains.

  2. Dicer-2-dependent activation of Culex Vago occurs via the TRAF-Rel2 signaling pathway.

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    Prasad N Paradkar

    2014-04-01

    Full Text Available Despite their importance as vectors of human and livestock diseases, relatively little is known about innate antiviral immune pathways in mosquitoes and other insects. Previous work has shown that Culex Vago (CxVago, which is induced and secreted from West Nile virus (WNV-infected mosquito cells, acts as a functional homolog of interferon, by activating Jak-STAT pathway and limiting virus replication in neighbouring cells. Here we describe the Dicer-2-dependent pathway leading to WNV-induced CxVago activation. Using a luciferase reporter assay, we show that a NF-κB-like binding site in CxVago promoter region is conserved in mosquito species and is responsible for induction of CxVago expression following WNV infection. Using dsRNA-based gene knockdown, we show that the NF-κB ortholog, Rel2, plays significant role in the signaling pathway that activates CxVago in mosquito cells in vitro and in vivo. Using similar approaches, we also show that TRAF, but not TRAF-3, is involved in activation of Rel2 after viral infection. Overall the study shows that a conserved signaling pathway, which is similar to mammalian interferon activation pathway, is responsible for the induction and antiviral activity of CxVago.

  3. Larvicidal activity of some Euphorbiaceae plant extracts against Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Rahuman, A Abdul; Gopalakrishnan, Geetha; Venkatesan, P; Geetha, Kannappan

    2008-04-01

    Larvicidal activity of ethyl acetate, butanol, and petroleum ether extracts of five species of Euphorbiaceae plants, Jatropha curcas, Pedilanthus tithymaloides, Phyllanthus amarus, Euphorbia hirta, and Euphorbia tirucalli, were tested against the early fourth instar larvae of Aedes aegypti L. and Culex quinquefasciatus (Say). The larval mortality was observed after 24 h of exposure. All extracts showed low larvicidal effects; however, the highest larval mortality was found in petroleum ether extract. The LC50 value of petroleum ether extracts of J. curcas, P. tithymaloides, P. amarus, E. hirta, and E. tirucalli were 8.79, 55.26, 90.92, 272.36, and 4.25 ppm, respectively, against A. aegypti and 11.34, 76.61, 113.40, 424.94, and 5.52 ppm, respectively, against C quinquefasciatus. Of the various ratios tested, the petroleum ether extracts of J. curcas and E. tirucalli were observed to be more efficient than the other plant extracts. It is, therefore, suggested that E. tirucalli can be applied as an ideal potential larvicide against A. aegypti and C. quinquefasciatus. This is an ideal ecofriendly approach for the control of the dengue vector, A. aegypti, and the lymphatic filariasis vector, C. quinquefasciatus.

  4. High Insecticides Resistance in Culex pipiens (Diptera: Culicidae from Tehran, Capital of Iran

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    Yaser Salim-Abadi

    2016-10-01

    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.

  5. Actividad de picadura de Culex quinquefasciatus (SAY, 1863 en Bogotá, Colombia

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    Marco Andrés Rojas-Mogollón

    2013-09-01

    Full Text Available Resumen Antecedentes. La presencia de mosquitos en el sur de Bogotá se constituye en una molestia sanitaria debido a sus altas densidades. Objetivo. Caracterizar la abundancia mensual y la actividad de picadura de los mosquitos. Materiales y métodos. Se recolectaron mosquitos utilizando trampas Shannon, durante una noche por mes y por un periodo de seis meses, en dos sitios aledaños a fosos de excavación minera, inundadas por el río Tunjuelito. Resultados. Se recolectaron un total de 18891 mosquitos. 99,93% se determinaron como culex quinquefasciatus. Los meses de mayor abundancia de mosquitos fueron marzo y abril, los cuales presentan mayor precipitación. Se encontraron dos patrones de actividad nocturna, uno con un solo pico hacia la media noche en el sitio más cercano a las minas de excavación y otro con dos picos definidos en el sitio más cercano a las viviendas. La tasa de paridad fue de 64,4%. Conclusión. Este comportamiento diferente posiblemente esté asociado a las condiciones microambientales, como luz y actividad minera de la zona durante las 24 horas del día, pero no se encontró que estuviera relacionado con la presencia o ausencia de lluvia.

  6. Efficiency of Colocasia esculenta leaves extract and histopathological effects on Culex pipiens (Diptera: Culicidae).

    Science.gov (United States)

    El-Monairy, Olfat M

    2015-04-01

    This study evaluated the toxicity of Colocasia esculenta leaves extract on 3rd, 4th instars larvae and pupae of Culex pipiens. Bioassays showed that the 3rd instar larvae was the most susceptible to the different concentrations of extract, where the LC50 after 48 hr. post-exposure was 79.41, 109.65 & 141.25 for the 3rd, 4th instars larvae and pupal stage respectively. The histo-pathological effects of C. esculenta leaves extract on midgut regions and gastric caeca of the 3rd instar larvae were studied. When larvae were treated with 100 ppm of C. esculenta extract, all larvae developed dramatic pathological lesions especially Malpighian tubules were extensively affected. The midgut cells showed morphological deviation from normal ones, through slightly apical degenerated (lysis) of epithelial cells. The epithelial cells with extensive cellular microvilli were shrinkage, the nuclei showed pyknotic characteristic and the peritrophic membrane was appeared discontinuation in compared to control. When the 3rd larval instar was exposed to extract 400 ppm, the epithelial cells, adipose fabric and muscles were extensively affected. Also, the gastric caeca was affected obviously. These observation and alterations in cells of Cx. pipiens larvae are related to the dangerous effect of C. esculent leaves extract.

  7. SR450 And Superhawk XP Applications Of Bacillus thuringiensis israelensis Against Culex quinquefasciatus.

    Science.gov (United States)

    Dunford, James C; Stoops, Craig A; Estep, Alden S; Britch, Seth C; Richardson, Alec G; Walker, Todd W; Farooq, Muhammad; Hoel, David F; Platt, Raymond R; Smith, Vincent L; Wirtz, Robert A; Kerce, Jerry D

    2014-09-01

    Sprayer comparisons and larval morality assays were conducted following SR450 backpack mist blower and Superhawk XP thermal fogger applications of Vectobac® WDG Bacillus thuringiensis israelensis (Bti) against Culex quinquefasciatus. Bacillus thuringiensis israelensis was applied at maximum label rate in a 232.26-m(2) field plot located in north-central Florida with containers placed at 2 heights (ground level and 1.52 m above ground) on stakes positioned 3.04, 6.09, 9.14, 12.19, and 15.24 m from the spray line. Results indicated that there was no significant (P > 0.05) difference in 24- and 48-h larval mortality between the 2 sprayers or between the 2 heights. There was significant difference (P 70% larval mortality 3.04-9.14 m from the spray line, and <60% mortality at 12.19 and 15.24 m. The data suggest that the SR450 and Superhawk XP may be comparable sprayers for use with Bti to control mosquito larvae.

  8. Alterations in the fat body and midgut of Culex quinquefasciatus larvae following exposure to different insecticides.

    Science.gov (United States)

    Alves, Stênio Nunes; Serrão, José Eduardo; Melo, Alan Lane

    2010-08-01

    This study describes morphological alterations in the fat body and midgut of Culex quinquefasciatus larvae following exposure to different insecticides. To this end, both third and fourth instars of C. quinquefasciatus larvae were exposed for 30 and 60 min to organophosphate (50 ppb), pyrethroids (20 and 30 ppb), and avermectin derivates (1.5 and 54 ppb). Following incubation, pH measurements of the larvae gut were recorded. The fat body and midgut were also analyzed by light and transmission electron microscopy. These studies demonstrate a decrease in the pH of the larvae anterior midgut following exposure to all of the tested insecticides. Histochemical tests revealed a strong reaction for neutral lipids in the control group and a marked decrease in the group exposed to cypermethrin. Furthermore, a weak reaction with acidic lipids in larvae exposed to deltamethrin, temephos, ivermectin and abamectin was also observed. Insecticide-exposed larvae also exhibited cytoplasm granule differences, relative to control larvae. Finally, we noted a small reduction in microvilli size in the apex of digestive cells, although vesicles were found to be present. The destructive changes in the larvae were very similar regardless of the type of insecticide analyzed. These data suggest that alterations in the fat body and midgut are a common response to cellular intoxication.

  9. Modeling the distribution of Culex tritaeniorhynchus to predict Japanese encephalitis distribution in the Republic of Korea.

    Science.gov (United States)

    Masuoka, Penny; Klein, Terry A; Kim, Heung-Chul; Claborn, David M; Achee, Nicole; Andre, Richard; Chamberlin, Judith; Small, Jennifer; Anyamba, Assaf; Lee, Dong-Kyu; Yi, Suk H; Sardelis, Michael; Ju, Young-Ran; Grieco, John

    2010-11-01

    Over 35,000 cases of Japanese encephalitis (JE) are reported worldwide each year. Culex tritaeniorhynchus is the primary vector of the JE virus, while wading birds are natural reservoirs and swine amplifying hosts. As part of a JE risk analysis, the ecological niche modeling programme, Maxent, was used to develop a predictive model for the distribution of Cx. tritaeniorhynchus in the Republic of Korea, using mosquito collection data, temperature, precipitation, elevation, land cover and the normalized difference vegetation index (NDVI). The resulting probability maps from the model were consistent with the known environmental limitations of the mosquito with low probabilities predicted for forest covered mountains. July minimum temperature and land cover were the most important variables in the model. Elevation, summer NDVI (July-September), precipitation in July, summer minimum temperature (May-August) and maximum temperature for fall and winter months also contributed to the model. Comparison of the Cx. tritaeniorhynchus model to the distribution of JE cases in the Republic of Korea from 2001 to 2009 showed that cases among a highly vaccinated Korean population were located in high-probability areas for Cx. tritaeniorhynchus. No recent JE cases were reported from the eastern coastline, where higher probabilities of mosquitoes were predicted, but where only small numbers of pigs are raised. The geographical distribution of reported JE cases corresponded closely with the predicted high-probability areas for Cx. tritaeniorhynchus, making the map a useful tool for health risk analysis that could be used for planning preventive public health measures.

  10. Artificial Selection for Different Host Preferences in Culex pipiens pallens (Diptera: Culicidae) Mosquitoes.

    Science.gov (United States)

    Yu, Jing; Li, Chun-Xiao; Dong, Yan-De; Xue, Rui-De; Zhao, Tong-Yan

    2015-09-01

    Most mosquito species display host preferences that are a crucial determinant of the transmission rate of mosquito-borne pathogens. Although a transgenic approach, based on driving genes for zoophily into vector populations, has been advocated as a malaria control strategy by the World Health Organization since 1982, the genes involved in mosquito host choice remain poorly understood. Culex pipiens pallens Coquillet mosquitoes were artificially selected for two different host preferences in a specially designed experimental enclosure. Of 3,035 mosquitoes obtained from larvae and pupae collected from the wild (the F0 generation), 27% preferentially fed on pigeons and 16% fed on mice. Following artificial selection for these host preferences over successive generations, the percentage of mosquitoes that preferred to feed on pigeons or mice gradually increased, eventually stabilizing at ∼55 and 34%, respectively, after the sixth generation. Intergenerational differences in host preferences were significant (P mosquitoes selected to prefer pigeons and those selected to prefer mice were both significant and consistent over almost six generations.

  11. Effectiveness of seven mosquito larvicides against the West Nile vector Culex pipiens (L. in Saudi Arabia

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    Jazem Abdullah Mahyoub

    2016-05-01

    Full Text Available Objective: To explore the effects of different chemical larvicides, bioinsecticides and insect growth regulators against the West Nile vector Culex pipiens (Diptera: Culicidae (Cx. pipiens in Saudi Arabia. Methods: We tested seven commercial mosquito larvicides, including classic cyfluthrin, diazinon and propoxur, bioinsecticides Bactilarvae and Tracer 24%, and insect growth regulators Baycidal and Sumilarv. LC50 and LC90 values were calculated in laboratory conditions using probit analysis. Results: Concerning chemical insecticides, the highest larval mortality was observed for diazinon, with LC50 = 0.352 3 mg/L, followed by propoxur and cyfluthrin. The bacterial insecticide Tracer was more effective than Bactilarvae (LC50 = 0.008 7 mg/L and 0.011 7 mg/L, respectively by 1.37 folds. Furthermore, Cx. pipiens larvae were more susceptible to insect growth regulators Baycidal (IC50 = 0.0004 mg/L if compared to Sumilarv (IC50 = 0.0029 mg/L by 7.25 folds. Conclusions: Overall, this research added basic knowledge about the effectiveness of seven mosquito larvicides with different mechanisms of action as potential candidates for the control programs of Cx. pipiens mosquito populations in Saudi Arabia.

  12. Adulticidal efficacy of Delonix elata against filariasis vector mosquito, Culex quinquefasciatus (Diptera: Culicidae

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    Mohan Rajeswary

    2014-09-01

    Full Text Available Objective: To evaluate the adulticidal activity and toxicity of different solvent crude extracts of Delonix elata (D. elata against filariasis vector mosquito Culex quinquefasciatus (Cx. quinquefasciatus. Methods: The adulticidal activities of crude hexane, benzene, ethyl acetate, chloroform and methanol leaf and seed extracts of D. elata were assayed for their toxicity against vector mosquito Cx. quinquefasciatus. Bioassay was carried out by WHO method for determination of adulticidal activity against mosquitoes. The adult mortality was observed after 24 h of exposure. Results: All extracts showed moderate adulticidal effects; however, the highest adult mortality was found in methanol extract of D. elata leaf against the adults of Cx. quinquefasciatus with the LC50 and LC90 values at 197.28 and 347.45mg/L, respectively. Conclusions: These results suggest that the leaf solvent plant extracts have the potential to be used as an ideal eco-friendly approach for the control of mosquitoes. This study provides first report on the mosquito adulticidal activity of D. elata plant extracts against filariasis vector mosquito, Cx. quinquefasciatus.

  13. Functional response analysis of Anisops sardea (Hemiptera: Notonectidae) against Culex quinquefasciatus in laboratory condition.

    Science.gov (United States)

    Mondal, Rajendra Prasad; Ghosh, Anupam; Bandyopadhyay, Subhasis; Chandra, Goutam

    2014-10-01

    Culex quinquefasciatus is the principal vector of lymphatic filariasis (LF). Application of alternative vector control methodologies are aimed at reduction of mosquito breeding sites and biting activity through the use of biological control methods. In the present study, functional response of aquatic Hemipteran backswimmer, Anisops sardea was assessed against Cx. quinquefasciatus larvae in laboratory bioassay. The functional respons of A. sardea was assessed against III(rd) instar larvae of Cx. quinquefasciatus. Respective handling times and coefficient of attack rates were determined by a non linear polynomeal regression equation. The results of rates of predation in variable prey densities exhibited a 'linear rise to plateau curve', associated with 'Type -II' functional response. The logistic regression estimated a significant negative linear parameter (P(1) <0) which also supported the same observation. Associated 'attack rates' and 'handling times' were also calculated using the Holling Disc Equation. The results of present experiments indicate that A. sardea can be used as a biocontrol agent against the larval forms of Cx. quinquefasciatus in temporarily available breeding places of mosquito with relatively clear water. However, a detailed field study has to be done to confirm these findings.

  14. The Morphological Variations of Culex pipiens Larvae (Diptera: Culicidae in Yazd Province, Central Iran

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    H Dehghan

    2010-12-01

    Methods: 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. Results: 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. Conclusion: 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.

  15. The Culex pipiens complex in continental Portugal: distribution and genetic structure.

    Science.gov (United States)

    Gomes, Bruno; Parreira, Ricardo; Sousa, Carla A; Novo, Maria T; Almeida, António P G; Donnelly, Martin J; Pinto, João

    2012-12-01

    Portugal is a southern European country that displays favorable ecological conditions for the establishment of West Nile virus (WNV) transmission cycles. Competent mosquito vector species are present throughout the country. Among the species with reported cases of WNV isolation in Portugal, Culex pipiens is the most ubiquitous and abundant mosquito. This species exhibits two biological forms with differences in host preferences. The molestus form has a greater tendency to feed upon humans and other mammals whereas the pipiens form prefers avian hosts. In northern latitudes, both forms are physically separated, with molestus occupying underground habitats and pipiens being found aboveground. However, the warmer climatic conditions of southern regions such as Portugal may favor the sympatric occurrence of both forms hence promoting interform hybridization. Genetic introgression between molestus and pipiens forms may result in a higher propensity for admixed populations to serve as bridge-vectors of WNV between humans and birds. Here we revise our present knowledge on the distribution, role in WNV transmission and genetic structure of the Cx. pipiens complex in continental Portugal. We focus on recent findings of sympatric molestus and pipiens populations that display considerable levels of hybridization and discuss the epidemiological repercussions of this occurrence.

  16. Larvicidal effects of various essential oils against Aedes, Anopheles, and Culex larvae (Diptera, Culicidae).

    Science.gov (United States)

    Amer, Abdelkrim; Mehlhorn, Heinz

    2006-09-01

    Mosquitoes in the larval stage are attractive targets for pesticides because mosquitoes breed in water, and thus, it is easy to deal with them in this habitat. The use of conventional pesticides in the water sources, however, introduces many risks to people and/or the environment. Natural pesticides, especially those derived from plants, are more promising in this aspect. Aromatic plants and their essential oils are very important sources of many compounds that are used in different respects. In this study, the oils of 41 plants were evaluated for their effects against third-instar larvae of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. At first, the oils were surveyed against A. aegypti using a 50-ppm solution. Thirteen oils from 41 plants (camphor, thyme, amyris, lemon, cedarwood, frankincense, dill, myrtle, juniper, black pepper, verbena, helichrysum and sandalwood) induced 100% mortality after 24 h, or even after shorter periods. The best oils were tested against third-instar larvae of the three mosquito species in concentrations of 1, 10, 50, 100 and 500 ppm. The lethal concentration 50 values of these oils ranged between 1 and 101.3 ppm against A. aegypti, between 9.7 and 101.4 ppm for A. stephensi and between 1 and 50.2 ppm for C. quinquefasciatus.

  17. Adulticidal efficacy of Delonix elata against filariasis vector mosquito, Culex quinquefasciatus (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Mohan Rajeswary; Marimuthu Govindarajan

    2014-01-01

    Objective: To evaluate the adulticidal activity and toxicity of different solvent crude extracts of Delonix elata (D. elata) against filariasis vector mosquito Culex quinquefasciatus (Cx. quinquefasciatus). Methods: The adulticidal activities of crude hexane, benzene, ethyl acetate, chloroform and methanol leaf and seed extracts of D. elata were assayed for their toxicity against vector mosquitoCx. quinquefasciatus. Bioassay was carried out by WHO method for determination of adulticidal activity against mosquitoes. The adult mortality was observed after 24 h of exposure. Results: All extracts showed moderate adulticidal effects; however, the highest adult mortality was found in methanol extract of D. elata leaf against the adults of Cx. quinquefasciatus with the LC50 and LC90 values at 197.28 and 347.45mg/L, respectively.Conclusions:These results suggest that the leaf solvent plant extracts have the potential to be used as an ideal eco-friendly approach for the control of mosquitoes. This study provides first report on the mosquito adulticidal activity of D. elata plant extracts against filariasis vector mosquito, Cx. quinquefasciatus.

  18. Differential Infectivities among Different Japanese Encephalitis Virus Genotypes in Culex quinquefasciatus Mosquitoes

    Science.gov (United States)

    Huang, Yan-Jang S.; Park, So Lee; Higgs, Stephen; Barrett, Alan D. T.; Hsu, Wei-Wen; Harbin, Julie N.; Cohnstaedt, Lee W.; Vanlandingham, Dana L.

    2016-01-01

    During the last 20 years, the epidemiology of Japanese encephalitis virus (JEV) has changed significantly in its endemic regions due to the gradual displacement of the previously dominant genotype III (GIII) with clade b of GI (GI-b). Whilst there is only limited genetic difference distinguishing the two GI clades (GI-a and GI-b), GI-b has shown a significantly wider and more rapid dispersal pattern in several regions in Asia than the GI-a clade, which remains restricted in its geographic distribution since its emergence. Although previously published molecular epidemiological evidence has shown distinct phylodynamic patterns, characterization of the two GI clades has only been limited to in vitro studies. In this study, Culex quinquefasciatus, a known competent JEV mosquito vector species, was orally challenged with three JEV strains each representing GI-a, GI-b, and GIII, respectively. Infection and dissemination were determined based on the detection of infectious viruses in homogenized mosquitoes. Detection of JEV RNA in mosquito saliva at 14 days post infection indicated that Cx. quinquefasciatus can be a competent vector species for both GI and GIII strains. Significantly higher infection rates in mosquitoes exposed to the GI-b and GIII strains than the GI-a strain suggest infectivity in arthropod vectors may lead to the selective advantage of previously and currently dominant genotypes. It could thus play a role in enzootic transmission cycles for the maintenance of JEV if this virus were ever to be introduced into North America. PMID:27706157

  19. Synergistic effect of Croton caudatus (fruits) and Tiliacora acuminata (flowers) extracts against filarial vector Culex quinquefasciatus

    Institute of Scientific and Technical Information of China (English)

    Someshwar Singha; Siddharthasankar Banerjee; Goutam Chandra

    2011-01-01

    Objective:To investigate the synergistic effect of crude and solvent extract of Croton caudatus (C. caudatus ) (fruits) and Tiliacora acuminata (T. acuminata) (flowers) against the larval form of Culex quinquefasciatus (Cx. quinquefasciatus). Methods: Crude and solvent [chloroform:methanol (1:1 v/v), benzene and ethyl acetate] extracts of two plants, C. caudatus (fruits) and T. acuminata (flowers) were examined separately against filarial vector Cx. quinquefasciatus larvae with gradually increasing concentration i.e. from 0.1%to 0.5%of crude extract and 25 ppm to 75 ppm of solvent extracts. To observe the synergistic effect, if any, extracts of these two plant parts were mixed at different concentrations and treated against mosquito larvae. Phytochemical analyses of extracts of both the plant parts were carried out. Results: In a 72-h bioassay experiment with plant extracts, highest mortalities were recorded at 0.5% (crude) and 75 ppm (solvent) concentration for fruits of C. caudatus and flowers of T. acuminata individually. For synergistic effect, only 0.2%of the mixture of these two crude extracts and 75 ppm concentration of chloroform:methanol (1:1 v/v) and ethyl acetate extracts showed 100%mortality after 24 h and 48 h of exposure respectively. Conclusions:In the field of mosquito control, insecticides of plant origin may serve as suitable alternative to the toxic chemicals. Some secondary metabolites in combination may be responsible for better larvicidal activity.

  20. KOMPOSISI SPESIES DAN DOMINASI NYAMUK CULEX DI DAERAH ENDEMIS FILARIASIS LIMFATIK DI KELURAHAN PABEAN KOTA PEKALONGAN

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    Tri Ramadhani

    2012-11-01

    Full Text Available Filariasis is one of the communicable disease which is caused by infestation of Filaria wonn. The disease is transmitted by various mosquitoes. Pabean village was one of the endemic area in Pekalongan city with lymphatic filariasis problem (microfilariae rate >1 %. The research aimed to get species and dominan potencial vector filariasis and breeding place.The reseach was an observational study which used cross sectional design. The activity were mosquitoes, larve dipper and pupa collection from August until December 2007. The mosquitoes collection was done twice a week by landing collection and light trap with dry ice.The result showed that the species culex mosquitoes found 19.229, consisted of four species that is Cx.quinquefasciatus, Cx.bitaeniorhynchus, Cx. tritaeniorhynchus, and Cx. vishnui. Mosquito of Cx.quinquefasciatus most dominantly found at all of way of arrest and known as mosquito of vector potential of lymphatic filariasis in Pabean village. Especial breeding place of Cx.quinquefasciatus is water polution and very bad sanitation. The larval density was more than 100 of dipper.

  1. Use of floating layers of polystyrene beads to control populations of the filaria vector Culex quinquefasciatus.

    Science.gov (United States)

    Curtis, C F; Malecela-Lazaro, M; Reuben, R; Maxwell, C A

    2002-12-01

    Floating layers of polystyrene beads suffocate mosquito larvae and pupae and inhibit egg laying. The layers are very durable in breeding sites with water contained within walls, as in wet pit latrines and soakage pits. In some areas such pits constitute an important breeding site for Culex quinquefasciatus. Trials have been conducted in communities in Zanzibar, Tanzania, and in Tamil Nadu, India, where such mosquito populations were the vectors of Wuchereria bancrofti. In each case, treatment of all the pits with polystyrene beads was integrated with mass treatment of the people with antifilarial drugs-in Zanzibar in 1988 with diethylcarbamazine (DEC) and in India in the 1990s with DEC plus ivermectin. The results were compared with those in communities with the mass drug treatment alone and with control communities with neither treatment. The polystyrene-bead treatments greatly and sustainably reduced the vector populations. Comparison of the communities after drug treatment ceased showed that this form of vector control contributed markedly to the prevention of a resurgence of filarial infection. Where Cx. quinquefasciatus breeding in pits form a major component of the vector population, use of polystyrene-bead layers could assist considerably in the process of eliminating lymphatic filariasis by mass drug administration.

  2. Population dynamics of Culex quinquefasciatus filaria vector in Raipur City of Chhattisgarh State.

    Science.gov (United States)

    Dixit, Vandana; Gupta, A K; Kataria, Om; Prasad, G B K S

    2002-09-01

    Indoor resting Culex quinquefasciatus were collected from 17 localities of Raipur City using aspirator tube between 06.00 and 08.00 hrs. at monthly intervals for over a period of 12 months. Mosquitoes were also collected using animal and human baits. A total of 4973 C. quinquefasciatus were collected in 176 man hours from different locations of Raipur City with a mean density of 28.26 pmh. The vector was recorded throughout the year with higher densities during the months of March (44.29 pmh), February (41.29 pmh), August (38.58 pmh) and April (37.17 pmh). The lower densities were recorded during July (17.05 pmh), September (16.82 pmh) and November (16.64 pmh). The Gudhyari and Amanaka localities recorded the highest and lowest densities of C. quinquefasciatus respectively. No significant relationship was observed between the density variation of the vector and variation in temperature and/or humidity in the study region.

  3. Larvicidal activity of essential extract of Rosmarinus officinalis against Culex quinquefasciatus.

    Science.gov (United States)

    Yu, Jing; Liu, Xiang-Yi; Yang, Bin; Wang, Jie; Zhang, Fu-Qiang; Feng, Zi-Liang; Wang, Chen-Zhu; Fan, Quan-Shui

    2013-03-01

    Constituents in rosemary (Rosmarinus officinalis) have been shown to have larvicidal activity against invertebrates. In order to explore the properties of crude extract of rosemary further, we studied the chemical composition and its activity against dichlorodiphenyltrichloroethane (DDT)-susceptible, DDT-resistant, and field strains of Culex quinquefasciatus larvae. The major components of R. officinalis were found to be eucalyptol and camphor, with relative percentages of 10.93% and 5.51%, respectively. Minor constituents included limonene, (+)-4-carene, isoborneol, 1-methyl-4-(1-methylethylidene)-cyclohexene, and pinene. The median lethal concentration (LC50) values of the essential oil of R. officinalis against DDT-susceptible, DDT-resistant, and field strains of larvae of Cx. quinquefasciatus were 30.6, 26.4, and 38.3 mg/liter, respectively. The single median lethal dose (LD50) in Kunming mice was 4752 mg/kg. Essential oils from R. officinalis may, therefore, provide an effective natural plant product for use in mosquito prevention and control.

  4. Laboratory development of permethrin resistance and cross-resistance pattern of Culex quinquefasciatus to other insecticides.

    Science.gov (United States)

    Ramkumar, Govindaraju; Shivakumar, Muthugoundar S

    2015-07-01

    Resistance of mosquitoes to insecticides is a growing concern in India. Since only a few insecticides are used for public health and limited development of new molecules is expected in the next decade, maintaining the efficacy of control programs mostly relies on resistance management strategies. Developing such strategies requires a deep understanding of factors influencing resistance together with characterizing the mechanisms involved. Among factors likely to influence insecticide resistance in mosquitoes, agriculture and urbanization have been implicated but rarely studied in detail. In the present study, we evaluate the permethrin resistance and cross-resistance pattern of several insecticides in Culex quinquefasciatus mosquitoes. After 10 generation of selection with permethrin, the LC50 value for both larvae and adult Cx. quinquefasciatus was increased by 17.3- and 17.1-folds compared with susceptible strain. Detoxification enzyme profiles and native PAGE electrophoresis of esterase isoenzyme further revealed that esterase and CytP450 may be involved in permethrin resistance (PerRes) strain compared with susceptible strain. In addition to cross-resistance, study revealed that high resistance to cypermethrin (RR = 6.3, 8.8-folds). This study provided important information for understanding permethrin resistance and facilitating a better strategy for the management of resistance. These studies conclude that a strong foundation for further study of permethrin resistance mechanisms observed in Cx. quinquefasciatus mosquitoes.

  5. Development of Resistance to Pyrethroid in Culex pipiens pallens Population under Different Insecticide Selection Pressures.

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    Linna Shi

    Full Text Available Current vector control programs are largely dependent on pyrethroids, which are the most commonly used and only insecticides recommended by the World Health Organization for insecticide-treated nets (ITNs. However, the rapid spread of pyrethroid resistance worldwide compromises the effectiveness of control programs and threatens public health. Since few new insecticide classes for vector control are anticipated, limiting the development of resistance is crucial for prolonging efficacy of pyrethroids. In this study, we exposed a field-collected population of Culex pipiens pallens to different insecticide selection intensities to dynamically monitor the development of resistance. Moreover, we detected kdr mutations and three detoxification enzyme activities in order to explore the evolutionary mechanism of pyrethroid resistance. Our results revealed that the level of pyrethroid resistance was proportional to the insecticide selection pressure. The kdr and metabolic resistance both contributed to pyrethroid resistance in the Cx. pipiens pallens populations, but they had different roles under different selection pressures. We have provided important evidence for better understanding of the development and mechanisms of pyrethroid resistance which may guide future insecticide use and vector management in order to avoid or delay resistance.

  6. Dicer-2-dependent activation of Culex Vago occurs via the TRAF-Rel2 signaling pathway.

    Science.gov (United States)

    Paradkar, Prasad N; Duchemin, Jean-Bernard; Voysey, Rhonda; Walker, Peter J

    2014-04-01

    Despite their importance as vectors of human and livestock diseases, relatively little is known about innate antiviral immune pathways in mosquitoes and other insects. Previous work has shown that Culex Vago (CxVago), which is induced and secreted from West Nile virus (WNV)-infected mosquito cells, acts as a functional homolog of interferon, by activating Jak-STAT pathway and limiting virus replication in neighbouring cells. Here we describe the Dicer-2-dependent pathway leading to WNV-induced CxVago activation. Using a luciferase reporter assay, we show that a NF-κB-like binding site in CxVago promoter region is conserved in mosquito species and is responsible for induction of CxVago expression following WNV infection. Using dsRNA-based gene knockdown, we show that the NF-κB ortholog, Rel2, plays significant role in the signaling pathway that activates CxVago in mosquito cells in vitro and in vivo. Using similar approaches, we also show that TRAF, but not TRAF-3, is involved in activation of Rel2 after viral infection. Overall the study shows that a conserved signaling pathway, which is similar to mammalian interferon activation pathway, is responsible for the induction and antiviral activity of CxVago.

  7. Laboratory and field evaluation of an oviposition trap for Culex quinquefasciatus(Diptera: Culicidae

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    Rosângela MR Barbosa

    2007-06-01

    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.

  8. Larvicidal activities of three plants against filarial vector Culex quinquefasciatus Say (Diptera: Culicidae).

    Science.gov (United States)

    Rawani, Anjali; Haldar, Koyel Mallick; Ghosh, Anupam; Chandra, Goutam

    2009-10-01

    The present study was carried out to establish the larvicidal properties of crude extracts of three plants, viz. Carica papaya, Murraya paniculata and Cleistanthus collinus against Culex quinquefasciatus as target species. The relative efficacy of the plant extracts in vector control was as follows: C. papaya seed extract > M. paniculata fruit extract > M. paniculata leaf extract > C. collinus leaf extract. Result of log-probit analysis (at 95% confidence level) revealed that LC(50) and LC(95) values gradually decreased with the exposure periods similar to the result in bioassay experiment for each of the plant extract. The results of preliminary qualitative phytochemical analysis of all the plants revealed the presence of many bioactive principles such as steroids, alkaloids, terpenes, saponins, etc. that may be responsible for their biocontrol potentiality. The appropriate lethal concentrations at 24 h for each of the extracts were also studied on non-target organisms such as Diplonychus annulatum and Chironomus circumdatus, and no change in the swimming behaviour and survivality was noticed, which indicates that all the extracts are safe for the aquatic ecosystem.

  9. Entomopathogenic fungus generated Nanoparticles for enhancement of efficacy in Culex quinquefasciatus and Anopheles stephensi

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    N. SONI, S. PRAKASH

    2012-05-01

    Full Text Available Objective: To evaluate to efficacy of silver and gold generated larvicide with the help of entomopathogenic fungus Chrysosporium tropicum against the Culex quinquefasciatus and Anopheles stephensi larvae. Methods: The silver and gold nanoparticles were quantified and observed by the Micro-scan reader and X-ray diffraction technique. The micrographs of silver and gold nanoparticles were obtained by the Transmission electron microscope and Scanning electron microscope. The larvicidal efficacy was then performed at six different log concentrations by the probit analysis. Results: The characterization study confirmed the spherical shaped and sized (20-50 and 2-15 nm of silver and gold nanoparticles. The all larval stages of Cx. quinquefasciatus were found more susceptible to the synthesized silver nanoparticles. Whereas, the larvae of An. stephensi were found more susceptible to larvicide synthesized with gold nanoparticles. Conclusions: The results suggested that the silver and gold nanoparticles generated by the entomopathogenic fungus C. tropicum is an environmentally safer and greener approach for mosquito control and new possibility in vector control strategy.

  10. The Arrival of the Northern House Mosquito Culex pipiens (Diptera: Culicidae) on Newfoundland's Avalon Peninsula.

    Science.gov (United States)

    Chaulk, Andrew C; Carson, Kate P; Whitney, Hugh G; Fonseca, Dina M; Chapman, Thomas W

    2016-11-01

    Culex pipiens L., the northern house mosquito, is the primary vector of West Nile virus to humans along the east coast of North America and thus the focus of much study. This species is an urban container-breeding mosquito whose close contact with humans and flexibility in host choice has led to its classification as a "bridge vector"; that is, it is thought to move zoonotic diseases to humans from vertebrate reservoirs. While this invasive species is now well documented in its established range, which expanded in 2001 to include Canada, the existence of populations of this species along the fringes of its range are less well known. Here we report, using morphological and genetic techniques, the existence of two locations where Cx. pipiens exists in Newfoundland in both expected and unexpected sites based on projected habitat suitability on the island. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Mosquito larvicidal activity of Rauvolfia serpentina L. seeds against Culex quinquefasciatus Say

    Institute of Scientific and Technical Information of China (English)

    Dipanwita Das; Goutam Chandra

    2012-01-01

    Objective:To establish the larvicidal activities, if any of solvent extracts of Rauvolfia serpentina (R. serpentina) L. seeds against Culex quinquefasciatus (Cx. quinquefasciatus) Say, 1823 as target species. Methods:Seeds of R. serpentina were extracted with five solvents graded according to the polarity [viz. petroleum ether, benzene, ethyl acetate, acetone and absolute alcohol] continuing one after another with the same seeds. Results:Mortality rate with petroleum ether extract was significantly higher than other extracts. The mortality rates of late 3rd instar larvae were 50.33±5.51, 10.00±1.00, 0.00±0.00, 21.33±1.53 and 0.00±0.00 in 100 ppm concentration of petroleum ether, benzene, ethyl acetate, acetone and absolute alcohol respectively, after 24 h of exposure period. Conclusions:Results of this study show that petroleum ether extract of R. serpentina seed may be considered as a potent source of mosquito larvicidal agent.

  12. Vector competence of Culex quinquefasciatus say from different regions of Brazil to Dirofilaria immitis

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    Ahid Silvia Maria Mendes

    2000-01-01

    Full Text Available The vector competence of Culex quinquefasciatus from five localities in Brazil to Dirofilaria immitis was evaluated experimentally. Females from each locality were fed on an infected dog (~ 6 microfilariae/µl blood. A sample of blood fed mosquitoes were dissected approximately 1 h after blood meal. These results demonstrated that all had ingested microfilariae (mean, 4.8 to 24.6 microfilariae/mosquito. Fifteen days after the infected blood meal, the infection and infective rates were low in all populations of Cx. quinquefasciatus. The mean number of infective larvae detected in the head and proboscis of these mosquitoes was 1-1.5. The vector efficiency, the number of microfilariae ingested/number of infective larvae, was low for all populations of Cx. quinquefasciatus. However, the survival rate for all populations was high (range 50-75%. The survival rate of Aedes aegypti assayed simultaneously for comparison was low (24.7%, while the vector efficiency was much higher than for Cx. quinquefasciatus. These data suggest that the vector competence of all assayed populations of Cx. quinquefasciatus to D. immitis in Brazil is similar and that this species is a secondary vector due to its low susceptibility. Nevertheless, vector capacity may vary between populations due to differences in biting frequency on dogs that has been reported in Brazil.

  13. Susceptibilidade larval de populações de Aedes aegypti e Culex quinquefasciatus a inseticidas químicos Larval susceptibility of Aedes aegypti and Culex quinquefasciatus populations to chemical insecticides

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    Jairo Campos

    2003-08-01

    Full Text Available OBJETIVO: Avaliar a susceptibilidade a inseticidas químicos de larvas de Culex quinquefasciatus e Aedes aegypti, provenientes de áreas sujeitas ou não a tratamentos de controle. MÉTODOS: Foram coletadas larvas de mosquitos em uma área não sujeita a tratamentos com inseticidas (Campinas, SP e em áreas sujeitas a esses tratamentos (Campo Grande, MS e Cuiabá, MT. Foram usados bioensaios com concentrações diagnóstico e concentrações múltipla de inseticidas organofosforados e piretróides, segundo padrão da Organização Mundial de Saúde, para avaliar a susceptibilidade dessas larvas. RESULTADOS: Ensaios com larvas de Culex quinquefasciatus de Campinas, SP, permitiram a suspeita de resistência à cipermetrina e evidenciaram resistência à ciflutrina. Larvas dessa espécie coletadas em Campo Grande, MS, e Campinas, SP, apresentaram resistência ao temephos. Para a colônia campineira desta espécie, foram estabelecidas as razões de resistência: RR50=6,36 e RR95=4,94, com base em linhagem susceptível padrão. Adicionalmente, os testes com Aedes aegypti mostraram susceptibilidade similar ao temephos em uma população de campo (Cuiabá, MT e uma de laboratório. CONCLUSÕES: Os resultados indicam resistência a organofosforado e piretróides em Culex quinquefasciatus, evidenciando a necessidade de avaliações e monitoramento da efetividade dos inseticidas a serem usados nos programas de controle de mosquitos.OBJECTIVE: To evaluate the susceptibility to chemical insecticides of Culex quinquefasciatus and Aedes aegypt larvae from areas subjected to control treatments or not. METHODS: Bioassays for diagnostic concentration and multiple concentration were performed for organophosphate and pyrethroid insecticides according to World Health Organization parameters. The susceptibility was assessed for mosquito larvae collected from an area not subjected to chemical control (Campinas, State of São Paulo, SP and from other areas (Campo

  14. Effect of temperature on the development time and survival of preimaginal Culex hepperi (Diptera: Culicidae Efecto de la temperatura sobre el tiempo de desarrollo y la supervivencia preimaginal de Culex hepperi (Diptera: Culicidae

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    María Verónica Loetti

    2008-12-01

    Full Text Available The aim of this research was to evaluate the effect of temperature on the development time and survival of Culex (Culex hepperi Casal and García, 1967. Individuals were reared in the laboratory, from the first larval stage to adult emergence, at five constant temperatures: 15, 20, 25, 30, and 33°C. The total development time was inversely related to temperature between 15 and 25°C. No differences were observed in the development time between sexes and no adults emerged at 33°C. In the larval stages III and IV, the time required for molting to the next stage increased at 30°C. The highest survival was recorded at 20°C. The more developed stages were less resistant to temperatures above and below 20°C. According to the nonlinear model of Briére, the lower and upper development thresholds were 2.6 and 33°C, respectively. Our results suggest that the effect of temperature depends upon the stage of development of C. hepperi.El objetivo de este trabajo fue analizar el efecto de la temperatura sobre el tiempo de desarrollo y la supervivencia preimaginal de Culex (Culex hepperi Casal y García, 1967. Los individuos fueron criados en laboratorio, desde el primer estadio larval hasta la emergencia del adulto, a cinco temperaturas constantes: 15, 20, 25, 30 y 33°C. El tiempo total de desarrollo se relacionó de manera inversa con la temperatura entre 15 y 25°C. No se detectaron diferencias entre sexos en el tiempo de desarrollo y ningún individuo alcanzó el estado adulto a 33°C. En los estadios larvales III y IV, el tiempo requerido para mudar al siguiente estadio fue mayor a 30°C. La supervivencia más alta se registró a 20°C. Los estadios más avanzados fueron menos resistentes a las temperaturas por encima y por debajo de los 20°C. De acuerdo con el modelo no lineal de Briére, los umbrales de desarrollo inferior y superior fueron 2.6 y 33°C, respectivamente. Nuestros resultados sugieren que el efecto de la temperatura depende del

  15. Assessment of anti mosquito measures in households and resistance status ofCulex species in urban areas in southern Ghana:Implications for the sustainability of ITN use

    Institute of Scientific and Technical Information of China (English)

    Andreas A Kudom; Ben A Mensah; Jacob Nunoo

    2013-01-01

    Objective:To determine resistance status ofCulex species to different class of insecticides and assess the major anti-mosquito strategies employed by urban households and their possible effects on malaria acquisition. Methods:Structured questionnaires were randomly administered to obtain information on demographic characteristics, measures that people use to prevent mosquito bites and their perception of where mosquitoes breed in their communities.Adult susceptibility assays were also carried out usingWHO discriminating dosages of four insecticides from different chemical classes againstCulex species.Results:Majority of respondents(54.75%) preferred the use of domestic insecticides in the form of aerosols and coils.Among households that used domestic insecticides, the use of coil was most frequent(62.9%) with a mean(95%CI) of9.18(8.99,9.37) coils per week.Strong level of pyrethroid-resistance and multiple insecticide resistance inCulex species were also detected in some of the study sites.Conclusions:The excessive use of domestic insecticides and high level of resistance inCulex species observed in the study area has implications for theITN component of the nation’s malaria control program in more subtle ways.People will lose interest in the use ofITN when it fails to protect users from bites of resistantCulex species.Excessive use of domestic insecticides may also select resistance in both malaria vectors andCulex species.On this account we recommend that nuisance mosquitoes must be controlled as part of malaria control programs to improve acceptance and utilization ofITN.

  16. Assessment of anti mosquito measures in households and resistance status of Culex species in urban areas in southern Ghana: implications for the sustainability of ITN use.

    Science.gov (United States)

    Kudom, Andreas A; Mensah, Ben A; Nunoo, Jacob

    2013-11-01

    To determine resistance status of Culex species to different class of insecticides and assess the major anti-mosquito strategies employed by urban households and their possible effects on malaria acquisition. Structured questionnaires were randomly administered to obtain information on demographic characteristics, measures that people use to prevent mosquito bites and their perception of where mosquitoes breed in their communities. Adult susceptibility assays were also carried out using WHO discriminating dosages of four insecticides from different chemical classes against Culex species. Majority of respondents (54.75%) preferred the use of domestic insecticides in the form of aerosols and coils. Among households that used domestic insecticides, the use of coil was most frequent (62.9%) with a mean (95% CI) of 9.18 (8.99, 9.37) coils per week. Strong level of pyrethroid-resistance and multiple insecticide resistance in Culex species were also detected in some of the study sites. The excessive use of domestic insecticides and high level of resistance in Culex species observed in the study area has implications for the ITN component of the nation's malaria control program in more subtle ways. People will lose interest in the use of ITN when it fails to protect users from bites of resistant Culex species. Excessive use of domestic insecticides may also select resistance in both malaria vectors and Culex species. On this account we recommend that nuisance mosquitoes must be controlled as part of malaria control programs to improve acceptance and utilization of ITN. Copyright © 2013 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  17. Tolerance to individual and joint effects of arsenic and Bacillus thuringiensis subsp. israelensis or Lysinibacillus sphaericus in Culex mosquitoes.

    Science.gov (United States)

    Mogren, Christina L; Walton, William E; Trumble, John T

    2014-08-01

    Arsenic contamination of global water supplies has come to the forefront in policy decisions in recent decades. However, the effects of arsenic on lower trophic levels of insects inhabiting contaminated ecosystems are not well understood. One approach to document both acute and sublethal effects of toxicants like arsenic is to assay them in combination with microbial pathogens to evaluate shifts in survival curves of the test organisms. Larvae of Culex quinquefasciatus and Culex tarsalis were reared in water containing 0 or 1 000 μg/L of arsenate or arsenite. Fourth instars were then exposed to a range of doses of Bacillus thuringiensis subsp. israelensis (Bti) or Lysinibacillus sphaericus (Ls), with shifts in lethal concentrations determined. Arsenic accumulation in 4th instars was also quantified, and a relative growth index (RGI) calculated for the treatments and compared to controls. Larvae of both species accumulated between 4 447 ± 169 ng As/g and 6 983 ± 367 ng As/g, though RGI values indicated accumulation did not affect growth and development. In all cases, the LC50 's and LC90 's of Cx. quinquefasciatus exposed jointly with arsenic and Bti/Ls were higher than Cx. tarsalis. Cx. tarsalis reared in arsenite showed a significant reduction in their Bti LC90 values compared to the control, indicating a sublethal effect of Bti. When exposed jointly with Ls, arsenite was more toxic than arsenate in Cx. tarsalis. Overall, these results indicate tolerance of these Culex species to arsenic exposures, and why this may occur is discussed.

  18. Susceptibilidade larval de populações de Aedes aegypti e Culex quinquefasciatus a inseticidas químicos

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    Campos Jairo

    2003-01-01

    Full Text Available OBJETIVO: Avaliar a susceptibilidade a inseticidas químicos de larvas de Culex quinquefasciatus e Aedes aegypti, provenientes de áreas sujeitas ou não a tratamentos de controle. MÉTODOS: Foram coletadas larvas de mosquitos em uma área não sujeita a tratamentos com inseticidas (Campinas, SP e em áreas sujeitas a esses tratamentos (Campo Grande, MS e Cuiabá, MT. Foram usados bioensaios com concentrações diagnóstico e concentrações múltipla de inseticidas organofosforados e piretróides, segundo padrão da Organização Mundial de Saúde, para avaliar a susceptibilidade dessas larvas. RESULTADOS: Ensaios com larvas de Culex quinquefasciatus de Campinas, SP, permitiram a suspeita de resistência à cipermetrina e evidenciaram resistência à ciflutrina. Larvas dessa espécie coletadas em Campo Grande, MS, e Campinas, SP, apresentaram resistência ao temephos. Para a colônia campineira desta espécie, foram estabelecidas as razões de resistência: RR50=6,36 e RR95=4,94, com base em linhagem susceptível padrão. Adicionalmente, os testes com Aedes aegypti mostraram susceptibilidade similar ao temephos em uma população de campo (Cuiabá, MT e uma de laboratório. CONCLUSÕES: Os resultados indicam resistência a organofosforado e piretróides em Culex quinquefasciatus, evidenciando a necessidade de avaliações e monitoramento da efetividade dos inseticidas a serem usados nos programas de controle de mosquitos.

  19. Oviposition deterrent activity from the ethanolic extract of Pongamia pinnata, Coleus forskohlii, and Datura stramonium leaves against Aedes aegypti and Culex quinquefaciatus.

    Science.gov (United States)

    Swathi, S; Murugananthan, G; Ghosh, S K

    2010-10-01

    Mosquitoes are responsible for spread of many diseases than any other group of arthropods. Diseases such as malaria, filariasis, dengue hemorrhagic fever (DHF), and chikunguinya are real threat to mankind. In the present study, ethanolic extracts of leaves of Pongamia pinnata, Coleus forskohlii, and Datura stramonium were evaluated for oviposition deterrent activity against Aedes aegypti and Culex quinquefasciatus. The oviposition deterrent tests of ethanolic extract of Pongamia pinnata, Coleus forskohlii, and Datura stramonium leaves reduced egg laying by 97.62%, 77.3%, 100% against Aedes aegypti and 59.10%, 39.22%, 82% against Culex quinquefasciatus at higher concentration (0.1%).

  20. Oviposition deterrent activity from the ethanolic extract of Pongamia pinnata, Coleus forskohlii, and Datura stramonium leaves against Aedes aegypti and Culex quinquefaciatus

    Directory of Open Access Journals (Sweden)

    S Swathi

    2010-01-01

    Full Text Available Mosquitoes are responsible for spread of many diseases than any other group of arthropods. Diseases such as malaria, filariasis, dengue hemorrhagic fever (DHF, and chikunguinya are real threat to mankind. In the present study, ethanolic extracts of leaves of Pongamia pinnata, Coleus forskohlii, and Datura stramonium were evaluated for oviposition deterrent activity against Aedes aegypti and Culex quinquefasciatus. The oviposition deterrent tests of ethanolic extract of Pongamia pinnata, Coleus forskohlii, and Datura stramonium leaves reduced egg laying by 97.62%, 77.3%, 100% against Aedes aegypti and 59.10%, 39.22%, 82% against Culex quinquefasciatus at higher concentration (0.1%.

  1. PERBANDINGAN PENGARUH BIOSIDA SANDOZ DENGAN BACTIMOS TERHADAP PENCEMAR BIOLOGIS, CULEX QUINQUEFASCIATUS DALAM SATU UJI COBA LAPANGAN DI JAKARTA, INDONESIA

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    I. G. Seregeg

    2012-09-01

    Full Text Available A field trial of Bacillus thuringiensis serotype H-14 has been done in Rawasari, Jakarta. Bacillus thuringiensis serotype H-14 under the trade-name of Sandoz 402 I in wde formulation and under the trade-name of Bactimos in wdp formulation is a specific agent against mosquito larvae (WHO mimeo. series, 1980. The result of the trial showed that both formulations have a short killing ef­fect, not more than one day against the larvae of Culex quinquefasciatus in Jakarta, Indonesia. Bactimos wdp has a better killing effect against early instar larvae as compared to Sandoz wdc.

  2. Pengaruh Pengasapan (Thermal Fogging Insektisida Piretroid (Malation 95% Terhadap Nyamuk Aedes aegypti dan Culex quinquefasciatus di Pemukiman

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    Hasan Boesri

    2009-12-01

    Full Text Available The evaluation of piretroid insecticide (active ingredient Malation 95% was con-ducted in Sub district Tengarang, Semarang Segency, Central Java Province. The insecti-cide was applied using thermal fogging method for dosages of 125, 250, 375, 500 and 625 ml/ha (diluted in diesel to 10 litters. The evaluation of the efficacy was conducted against two mosquito species, Aedes aegypti (the main dengue haemorrhagic fever and Culex quinquefasciatus (the urban lymphatic fil-ariasis vector. Result of the evaluation was revealed that dosages of 500 and 625 ml/ha were effective against both tested mosquito species indoor and outdoor.

  3. Synthesis and Larvicidal Activity against Culex pipiens pallens of New Triazole Derivatives of Phrymarolin from Phryma leptostachya L.

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    Ji-Wen Zhang

    2013-12-01

    Full Text Available Twelve new triazole derivatives of Phrymarolin were prepared from Phrymarolin I and the structures of all the derivatives were fully characterized by 1H-NMR, 13C-NMR and MS spectral data analyses. Larvicidal activities against 4rd instar larvae of Culex pipiens pallens of these Phrymarolin analogues were assayed. Although the triazole derivatives of Phrymarolin showed certain larvicidal activity, they showed lower activity than Phrymarolin I. The typical non-natural groups triazole substituents reduced the larvicidal activity of Phrymarolin derivatives.

  4. Aspectos da distribuição de Culex (Culex quinquefasciatus Say (Diptera, Culicidae na região do rio Pinheiros, na cidade de São Paulo, Estado de São Paulo, Brasil Aspects of the distribution of Culex (Culex quinquefasciatus Say (Diptera, Culicidae in the region of the Pinheiros River, in the city of São Paulo, State of São Paulo, Brazil

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    Sirlei Antunes de Morais

    2006-09-01

    Full Text Available A distribuição de Culex (Culex quinquefasciatus Say (1823 ao longo das margens do rio Pinheiros e os principais fatores que levam à proliferação da espécie foram estudados efetuando-se coletas semanais de mosquitos adultos, no período de um ano, em três pontos eqüidistantes às margens do rio. Para as coletas de mosquitos utilizou-se aspirador à bateria, por um período de cinco minutos. Os mosquitos foram identificados, diferenciados segundo o sexo e contados. Para verificação do estado fisiológico, as fêmeas foram separadas em vazias, com sangue e com ovos. Foram coletados 35.684 mosquitos, todos identificados como Cx. quinquefasciatus, sendo 39,4% fêmeas e 60,6% machos. As freqüências tomaram proporções diferentes entre os pontos de coletas e, em uma série temporal. O ambiente impactado do rio Pinheiros representa um excelente criadouro de Cx. quinquefasciatus, confirmado pela ocorrência de picos acentuados na freqüência de mosquitos, com desenvolvimento de forma explosiva e sobreposições entre as gerações, após as chuvas e em épocas de verão.The distribution of Culex (Culex quinquefasciatus Say (1823 along of the margins of the Pinheiros river and the main factors that lead to the proliferation of the species were studied doing weekly collections of adult mosquitoes, in the period of one year, in three equidistant points in the margins of the river. For the collections of mosquitoes battery vacuum cleaner was used, for a period of five minutes. The mosquitoes were identified, differentiated according to the sex and counted. For verification of the physiological state, the females were differentiated in empty, with blood or eggs. A total of 35.684 mosquitoes were captured, all of them were identified as Cx. quinquefasciatus, being 39.4% females and 60.6% males. The frequencies took different proportions between the points of collections and in a temporary series. The damaged environment of the Pinheiros river

  5. Evaluation of Bacillus sphaericus bioinsecticide produced with white soybean meal as culture medium for the control of Culex (Culex quinquefasciatus Avaliação do bioinseticida de Bacillus sphaericus, produzido com meio de cultivo de farelo branco de soja no controle de Culex (Culex quinquefasciatus

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    André L. A. Melo

    2009-03-01

    Full Text Available Bioinsecticides are shown to be useful in control programs to prevent several diseases, based on their specificity and efficiency against insect vectors. In the current study a bioinsecticide based on Bacillus sphaericus was produced using a white soybean culture medium and applied to larvae of Culex quinquefasciatus, the susceptible species, and Aedes aegypti, the refractory species used as the negative control. Efficacy was compared with that of the product fermented with the Luria Bertani (LB reference medium. The experiments showed that C. quinquefasciatus was highly susceptible to the product prepared with white soybean meal, reaching 100% larval mortality even at 10mg/L, while A. aegypti failed to reach 70% mortality at a concentration of 1g/L. By comparison with the reference medium, the proposed culture medium showed high larvicidal power, reaching a LD90 of 2.26mg/L, while 4.37mg/L was needed for the LB medium to achieve the same mortality rate. Cost comparison between the formulations favored the use of the bioinsecticide produced with white soybean meal. After factoring in the LD90 value, the cost ratio favored the new raw material by nearly 1:220.A utilização de bioinseticidas tem se mostrado útil aos programas de prevenção de diversas enfermidades devido a sua especificidade e eficiência contra insetos vetores. No presente trabalho, o bioinseticida de Bacillus sphaericus foi produzido com um meio de cultivo composto de farelo branco de soja e aplicado em larvas de Culex quinquefasciatus, espécie susce-tível, e Aedes aegypti, espécie refratária, usada como controle negativo. O desempenho foi comparado com o do produto fermentado com o meio referência Luria Bertani (LB. Os experimentos constataram que C. quinquefasciatus apresentou uma alta suscetibilidade ao produto produzido com farelo branco de soja, alcançando mortalidade de 100% mesmo na diluição de 10mg/L, enquanto A. aegypti não atingiu 70% na concentração de 1

  6. Wolbachia Endobacteria in Natural Populations of Culex pipiens of Iran and its Phylogenetic Congruence

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    Mohsen Karami

    2016-01-01

    Full Text Available Background: Wolbachia are common intracellular bacteria that infect different groups of arthropods including mos­quitoes. These bacteria modify host biology and may induce feminization, parthenogenesis, male killing and cyto­plasmic incompatibility (CI. Recently Wolbachia is being nominated as a bio-agent and paratransgenic candidate to control mosquito borne diseases.Methods: Here we report the results of a survey for presence, frequency, and phylogenetic congruence of these en­dosymbiont bacteria in Culex pipiens populations in Northern, Central, and Southern parts of Iran using nested-PCR amplification of wsp gene.Results: Wolbachia DNA were found in 227 (87.3% out of 260 wild-caught mosquitoes. The rate of infection in adult females ranged from 61.5% to 100%, while in males were from 80% to 100%. The Blast search and phyloge­netic analysis of the wsp gene sequence revealed that the Wolbachia strain from Iranian Cx. pipiens was identical to the Wolbachia strains of supergroup B previously reported in members of the Cx. pipiens complex. They had also identical sequence homology with the Wolbachia strains from a group of distinct arthropods including lepidopteran, wasps, flies, damselfly, thrips, and mites from remote geographical areas of the world.Conclusion: It is suggested that Wolbachia strains horizontally transfer between unrelated host organisms over evo­lutionary time. Also results of this study indicates that Wolbachia infections were highly prevalent infecting all Cx. pipiens populations throughout the country, however further study needs to define Wolbachia inter-population repro­ductive incompatibility pattern and its usefulness as a bio-agent control measure.

  7. Ovicidal activity of three insect growth regulators against Aedes and Culex mosquitoes.

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    Suman, Devi S; Wang, Yi; Bilgrami, Anwar L; Gaugler, Randy

    2013-10-01

    Interspecific variations in the susceptibility of freshly and embryonated eggs of Aedes albopictus, Ae. aegypti, Ae. atropalpus and Culex pipiens were tested against three classes of insect growth regulators (IGRs) including ecdysone agonist (azadirachtin), chitin synthesis inhibitor (diflubenzuron) and juvenile hormone analog (pyriproxyfen) at 0.001, 0.01, 0.1 and 1.0ppm concentrations. Egg hatching inhibition was dose dependent, the highest being at 1.0ppm concentration for freshly laid eggs of Ae. albopictus (pyriproxyfen: 80.6%, azadirachtin: 42.9% and diflubenzuron: 35.8%). Aedes aegypti showed lower egg hatching inhibition when exposed to pyriproxyfen (47.3%), azadirachtin (15.7%) and diflubenzuron (25.5%). Freshly laid eggs of Cx. pipiens were most susceptible to diflubenzuron. Aedes atropalpus eggs were tolerant to all three classes of IGRs. Embryonated eggs of Ae. albopictus, Ae. aegypti, Ae. atropalpus and Cx. pipiens were resistant to pyriproxyfen, azadirachtin and diflubenzuron than freshly laid eggs. The median desiccation time (DT50) of Ae. atropalpus eggs was maximum (5.1h) as compared to Ae. aegypti (4.9h), Ae. albopictus (3.9h) or Cx. pipiens (1.7h) eggs. Insignificant relationship between the rates of desiccation and egg hatching inhibition suggests other factors than physical providing eggs the ability to tolerate exposures to various IGRs. Egg hatching inhibition was due to the alteration in embryonic development caused by IGRs. Changes in the egg shell morphology and abnormal egg hatching from the side of the egg wall instead of operculum, was observed at higher concentrations of diflubenzuron. Morphological and physiological variations in eggs may be the key factor to influence the ovicidal efficacy of IGRs. The present data provide a base line for the improvement of the ovicidal efficacy of the insecticide and its formulation.

  8. Differential expression of salivary proteins between susceptible and insecticide-resistant mosquitoes of Culex quinquefasciatus.

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    Innocent Djegbe

    Full Text Available BACKGROUND: The Culex quinquefasciatus mosquito, a major pest and vector of filariasis and arboviruses in the tropics, has developed multiple resistance mechanisms to the main insecticide classes currently available in public health. Among them, the insensitive acetylcholinesterase (ace-1(R allele is widespread worldwide and confers cross-resistance to organophosphates and carbamates. Fortunately, in an insecticide-free environment, this mutation is associated with a severe genetic cost that can affect various life history traits. Salivary proteins are directly involved in human-vector contact during biting and therefore play a key role in pathogen transmission. METHODS AND RESULTS: An original proteomic approach combining 2D-electrophoresis and mass spectrometry was adopted to compare the salivary expression profiles of two strains of C. quinquefasciatus with the same genetic background but carrying either the ace-1(R resistance allele or not (wild type. Four salivary proteins were differentially expressed (>2 fold, P<0.05 in susceptible (SLAB and resistant (SR mosquito strains. Protein identification indicated that the D7 long form, a major salivary protein involved in blood feeding success, presented lower expression in the resistant strain than the susceptible strain. In contrast, three other proteins, including metabolic enzymes (endoplasmin, triosephosphate isomerase were significantly over-expressed in the salivary gland of ace-1(R resistant mosquitoes. A catalogue of 67 salivary proteins of C. quinquefasciatus sialotranscriptome was also identified and described. CONCLUSION: The "resistance"-dependent expression of salivary proteins in mosquitoes may have considerable impact on biting behaviour and hence on the capacity to transmit parasites/viruses to humans. The behaviour of susceptible and insecticide-resistant mosquitoes in the presence of vertebrate hosts and its impact on pathogen transmission urgently requires further

  9. Differential expression of salivary proteins between susceptible and insecticide-resistant mosquitoes of Culex quinquefasciatus.

    Science.gov (United States)

    Djegbe, Innocent; Cornelie, Sylvie; Rossignol, Marie; Demettre, Edith; Seveno, Martial; Remoue, Franck; Corbel, Vincent

    2011-03-23

    The Culex quinquefasciatus mosquito, a major pest and vector of filariasis and arboviruses in the tropics, has developed multiple resistance mechanisms to the main insecticide classes currently available in public health. Among them, the insensitive acetylcholinesterase (ace-1(R) allele) is widespread worldwide and confers cross-resistance to organophosphates and carbamates. Fortunately, in an insecticide-free environment, this mutation is associated with a severe genetic cost that can affect various life history traits. Salivary proteins are directly involved in human-vector contact during biting and therefore play a key role in pathogen transmission. An original proteomic approach combining 2D-electrophoresis and mass spectrometry was adopted to compare the salivary expression profiles of two strains of C. quinquefasciatus with the same genetic background but carrying either the ace-1(R) resistance allele or not (wild type). Four salivary proteins were differentially expressed (>2 fold, Pmosquito strains. Protein identification indicated that the D7 long form, a major salivary protein involved in blood feeding success, presented lower expression in the resistant strain than the susceptible strain. In contrast, three other proteins, including metabolic enzymes (endoplasmin, triosephosphate isomerase) were significantly over-expressed in the salivary gland of ace-1(R) resistant mosquitoes. A catalogue of 67 salivary proteins of C. quinquefasciatus sialotranscriptome was also identified and described. The "resistance"-dependent expression of salivary proteins in mosquitoes may have considerable impact on biting behaviour and hence on the capacity to transmit parasites/viruses to humans. The behaviour of susceptible and insecticide-resistant mosquitoes in the presence of vertebrate hosts and its impact on pathogen transmission urgently requires further investigation. All proteomic data will be deposited at PRIDE (http://www.ebi.ac.uk/pride/).

  10. Insecticide Susceptibility of Field-Collected Populations of Culex tritaeniorhynchus in the Republic of Korea

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    Yoo, Dae-Hyun; Shin, E-Hyun; Lee, Dong-Kyu; Ahn, Young Joon; Kim, Hyun-Kyung; Kim, Seong-Yoon; Park, Chan

    2013-01-01

    The toxicities of 10 insecticides were examined against late third instar Culex tritaeniorhynchus Giles (Diptera: Culicidae) using the direct-contact mortality bioassay. Six geospatially-distant field mosquitoes were collected from Chuncheon-si, Hwaseong, Seosan. Jeonju, Daegu, and Busan in the Republic of Korea. Marked regional variations of insecticide susceptibility were observed. Field populations of Seosan, Jeonju, and Daegu from agricultural areas showed higher to extremely higher insecticide susceptibility to pyrethroids than those of Chuncheon-si, Hwaseong, and Busan strains from non-agricultural areas. Extremely high to low levels of susceptibility were measured: bifenthrin, susceptible ratio (SR) = 2.7–896.3; β-cyfluthrin, SR = 1.8–633.3; α-cypermethrin, SR = 1.2–1,051.9; deltamethrin, SR = 1.3–711.1; permethrin, SR = 1.5–1,053.4; etofenprox, SR = 2.2–29.3; chlorfenapyr, SR = 5.1–103.6; chlorpyrifos, SR = 2.3– 337.0; fenitrothion, SR = 2.0–142.3; and fenthion, SR = 1.4–186.2. Cx. tritaeniorhynchus populations from rice paddies had been under heavy selection pressure due to the agricultural insecticides, and that's why the mosquito species demonstrated high resistance to pyrethroids, which were used for a long time to control agricultural pests in the localities. These results indicate that careful selection and rotational use of these insecticides may result in continued satisfactory control against field populations of Japanese encephalitis vector mosquitoes. PMID:23879898

  11. Testing of UK Populations of Culex pipiens L. for Schmallenberg Virus Vector Competence and Their Colonization.

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    Robyn Manley

    Full Text Available Schmallenberg virus (SBV, an arboviral pathogen of ruminants, emerged in northern Europe during 2011 and has subsequently spread across a vast geographic area. While Culicoides biting midges (Diptera: Ceratopogonidae have been identified as a biological transmission agent of SBV, the role of mosquitoes (Diptera: Culicidae as potential vectors has not been defined beyond small-scale field collections in affected areas. Culex pipiens L. are one of the most widespread mosquitoes in northern Europe; they are present on farms across the region and have previously been implicated as vectors of several other arboviruses. We assessed the ability of three colony lines of Cx. pipiens, originating from geographically diverse field populations, to become fully infected by SBV using semi-quantitative real-time RT-PCR (sqPCR.Two colony lines of Cx. pipiens were created in the UK ('Brookwood' and 'Caldbeck' from field collections of larvae and pupae and characterised using genetic markers. A third strain of Cx. pipiens from CVI Wageningen, The Netherlands, was also screened during experiments. Intrathoracic inoculation of the Brookwood line resulted in infections after 14 days that were characterised by high levels of RNA throughout individuals, but which demonstrated indirect evidence of salivary gland barriers. Feeding of 322 individuals across the three colony lines on a membrane based infection system resulted in no evidence of full dissemination of SBV, although infections did occur in a small proportion of Cx. pipiens from each line.This study established two novel lines of Cx. pipiens mosquitoes of UK origin in the laboratory and subsequently tested their competence for SBV. Schmallenberg virus replication and dissemination was restricted, demonstrating that Cx. pipiens is unlikely to be an epidemiologically important vector of the virus in northern Europe.

  12. Evaluation of the pyrrole insecticide chlorfenapyr for the control of Culex quinquefasciatus Say.

    Science.gov (United States)

    Raghavendra, K; Barik, T K; Bhatt, R M; Srivastava, H C; Sreehari, U; Dash, A P

    2011-04-01

    Culex quinquefasciatus Say (Diptera: Culicidae) is a widely distributed mosquito vector species in India and also in other tropical regions of the world. This species is implicated in the transmission of lymphatic filariasis in many countries. This species is reported to be widely resistant to insecticides of different classes in current use. In the present study, bio-efficacy of chlorfenapyr, an insecticide of pyrrole class with a novel mode of action was tested for the control of Cx. quinquefasciatus. Studies were performed to determine the diagnostic dosage; residual efficacy on different artificially fabricated substrates, namely wood, mud, mud+lime, cement and cement+distemper; to assess cross-resistance with different insecticides; and synergism/antagonism using piperonyl butoxide (PBO). A dosage of 5.0% chlorfenapyr was determined as diagnostic dosage with 2 h exposure and 48 h holding period for assessing the susceptibility of mosquitoes. The residual efficacy was observed up to 34 weeks on wood and mud+lime substrates while on other substrates, it was about 15 weeks at a dosage of 400mg a.i./m(2). Laboratory-reared strains of Cx. quinquefasciatus showed cross-resistance, whereas field-collected mosquitoes showed absence of cross-resistance to chlorfenapyr. Potentiation bioassays showed antagonistic effect of PBO to chlorfenapyr toxicity owing to the involvement of oxidases in the initial step of a conversion of pro-insecticide chlorfenapyr to toxic form CL 303268. The present study results have shown that chlorfenapyr can be a potential insecticide for the control of multiple insecticide resistant strains of Cx. quinquefasciatus. However, in countries where indoor residual spray (IRS) is not targeted for the control of this species, like in India, chlorfenapyr used in IRS for the control of malaria vectors in rural and peri-urban areas can additionally provide control of Cx. quinquefasciatus also. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Dispersal of Culex quinquefasciatus (Diptera: Culicidae) in a Hawaiian rain forest

    Science.gov (United States)

    Lapointe, D.A.

    2008-01-01

    Introduced mosquito-borne pathogens avian malaria (Plasmodium relictum Grassi and Feletti) and avian pox virus (Avipoxvirus) have been implicated in the past extinctions and declines of Hawaiian avifauna and remain significant obstacles to the recovery and restoration of endemic Hawaiian birds. Effective management of avian disease will require extensive mosquito control efforts that are guided by the local ecology of the vector Culex quinquefasciatus Say (Diptera: Culicidae). During October and November 1997 and September through November 1998 five mark-release-recapture experiments with laboratory-reared Cx. quinquefasciatus were conducted in a native rain forest on Hawaii Island. Of the overall 66,047 fluorescent dye-marked and released females, 1,192 (1.8%) were recaptured in 43-52 CO2-baited traps operated for 10-12-d trapping periods. Recaptured mosquitoes were trapped in all directions and at distances up to 3 km from the release site. The cumulative mean distance traveled (MDTs) over the trapping period ranged from a high of 1.89 km after 11 d (September 1998) to a low of 0.81 km after 11 d (November 1998). Released mosquitoes moved predominately in a downwind direction and they seemed to use forestry roads as dispersal corridors. Applying an estimated MDT of 1.6 km to a geographical information system-generated map of the Hakalau Forest National Wildlife Refuge clearly demonstrated that the effective refuge area could be reduced 60% by mosquitoes infiltrating into managed refuge lands. These findings should have significant implications for the design of future refuges and development of effective mosquito-borne avian disease control strategies.

  14. Multiple-Insecticide Resistance and Classic Gene Mutations to Japanese Encephalitis Vector Culex tritaeniorhynchus from China.

    Science.gov (United States)

    Wu, Zhi-Ming; Chu, Hong-Liang; Wang, Gang; Zhu, Xiao-Juan; Guo, Xiao-Xia; Zhang, Ying-Mei; Xing, Dan; Yan, Ting; Zhao, Ming-Hui; Dong, Yan-De; Li, Chun-Xiao; Zhao, Tong-Yan

    2016-06-01

    Widespread resistance of insect pests to insecticides has been widely reported in China and there is consequently an urgent need to adjust pest management strategies appropriately. This requires detailed information on the extent and causes of resistance. The aim of the present study was to investigate levels of resistance to 5 insecticides among 12 strains of Culex tritaeniorhynchus, a major vector of Japanese encephalitis in China. Resistance to deltamethrin, beta-cypermethrin, permethrin, dichlorvos, and propoxur were measured using larval bioassays. The allelic frequency of knockdown resistance (kdr) and acetylcholinesterase (AChE) mutations were determined in all strains. Larval bioassay results indicated that the field strains collected from different sites were resistant to deltamethrin, beta-cypermethrin, permethrin, dichlorvos, and propoxur, with resistance ratio values ranging from 1.70- to 71.98-fold, 7.83- to 43.07-fold, 3.54- to 40.03-fold, 291.85- to 530.89-fold, and 51.32- to 108.83-fold, respectively. A polymerase chain reaction amplification of specific alleles method for individual was developed to detect genotypes of the AChE gene mutation F455W in Cx. tritaeniorhynchus. The frequency of the AChE gene mutation F455W was 100.00% in all strains, making this mutation of no value as a marker of resistance to organophosphorous and carbamate pesticides in Cx. tritaeniorhynchus in China. The kdr allele was present in all strains at frequencies of 10.00-29.55%. Regression analysis indicated a significant correlation between kdr allele frequencies and levels of resistance to deltamethrin, beta-cypermethrin, and permethrin. These results highlight the need to monitor and map insecticide resistance in Cx. tritaeniorhynchus and to adjust pesticide use to minimize the development of resistance in these mosquitoes.

  15. Cloning and characterization of two glutathione S-transferases from pyrethroid resistant Culex pipiens

    Science.gov (United States)

    Samra, Aman I; Kamita, Shizuo G; Yao, Hong-Wei; Cornel, Anthony J; Hammock, Bruce D

    2013-01-01

    BACKGROUND The Marin strain of Culex pipiens Say is a pyrethroid-resistant population that was collected in Marin County, California, in 2001 and subsequently maintained in the laboratory under regular permethrin exposure. RESULTS In this study, two genes, CpGSTd1 and CpGSTd2, encoding glutathione S-transferase (GST) were cloned from Cx. pipiens Marin. Phylogenetic analysis of the deduced amino acid sequences, CpGSTD1 and CpGSTD2, of these genes indicated that they belong to the Delta class of insect GSTs. The nucleotide and deduced amino acid sequences of CpGSTd1 and CpGSTd2 were 59% and 48% identical, respectively. CpGSTD1 and CpGSTD2 were expressed in Escherichia coli and purified by affinity chromatography. The recombinant GSTs exhibited unique selectivity towards the general GST substrates CDNB and DCNB, and also differed in their sensitivity to known inhibitors of GSTs. CpGSTD1 exhibited peroxidase activity with cumene hydroperoxide, while CpGSTD2 appeared to lack this activity. CpGSTD1 was able to metabolize DDT, while DDT metabolism by CpGSTD2 was not detectable. CpGSTD1 and CpGSTD2 showed no detectable metabolism of permethrin. Gene expression of CpGSTd1 and CpGSTd2 in Marin mosquitoes was elevated by about 2-fold in comparison to that found in a pyrethroid-sensitive mosquito strain. CONCLUSION Our results indicated that CpGSTD1 and CpGSTD2 have unique biochemical characteristics but they did not appear to play major roles in permethrin resistance in Marin mosquitoes. PMID:22290868

  16. European Aedes albopictus and Culex pipiens Are Competent Vectors for Japanese Encephalitis Virus

    Science.gov (United States)

    Desprès, Philippe

    2017-01-01

    Background 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. Findings 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. Conclusions 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. PMID:28085881

  17. Reverse and conventional chemical ecology approaches for the development of oviposition attractants for Culex mosquitoes.

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    Walter S Leal

    Full Text Available Synthetic mosquito oviposition attractants are sorely needed for surveillance and control programs for Culex species, which are major vectors of pathogens causing various human diseases, including filariasis, encephalitis, and West Nile encephalomyelitis. We employed novel and conventional chemical ecology approaches to identify potential attractants, which were demonstrated in field tests to be effective for monitoring populations of Cx. p. quinquefasciatus in human dwellings. Immunohistochemistry studies showed that an odorant-binding protein from this species, CquiOBP1, is expressed in trichoid sensilla on the antennae, including short, sharp-tipped trichoid sensilla type, which house an olfactory receptor neuron sensitive to a previously identified mosquito oviposition pheromone (MOP, 6-acetoxy-5-hexadecanolide. CquiOBP1 exists in monomeric and dimeric forms. Monomeric CquiOBP1 bound MOP in a pH-dependent manner, with a change in secondary structure apparently related to the loss of binding at low pH. The pheromone antipode showed higher affinity than the natural stereoisomer. By using both CquiOBP1 as a molecular target in binding assays and gas chromatography-electroantennographic detection (GC-EAD, we identified nonanal, trimethylamine (TMA, and skatole as test compounds. Extensive field evaluations in Recife, Brazil, a region with high populations of Cx. p. quinquefasciatus, showed that a combination of TMA (0.9 microg/l and nonanal (0.15 ng/microl is equivalent in attraction to the currently used infusion-based lure, and superior in that the offensive smell of infusions was eliminated in the newly developed synthetic mixture.

  18. Aqueous neem extract versus neem powder on Culex quinquefasciatus: implications for control in anthropogenic habitats.

    Science.gov (United States)

    Kudom, Andreas A; Mensah, Ben A; Botchey, Mary A

    2011-01-01

    Control programs using conventional insecticides to target anthropogenic mosquito habitats are very expensive because these habitats are widespread, particularly in cities of most African countries. Additionally, there are serious environmental concerns regarding large-scale application of most conventional insecticides. Clearly there is a need for alternative methods that are more effective, less expensive, and environmentally friendly. One such method would be the application of preparations made from parts of the neem tree, Azadirachta indica A. Jussieu (Sapindales: Meliaceae). In this study, aqueous crude extracts and crude powder were prepared from different parts of neem, and the efficacies of the preparations on juvenile stages of Culex quinquefasciatus Say (Diptera: Culicidae) were evaluated in the laboratory. When larvae were exposed to a concentration of 0.1 g/mL extract for 24 hours, percent mean mortality (± SE) was 72.7 plusmn; 1.8 for the bark, 68.7 ± 1.6 for fruits and 60 ± 1.6 for leaves. These means were not significantly different (χ(2) = 4.12; df = 2; p = 0.127). At a concentration of 0.01 g/mL, > 95% of the larvae died within 24 hours of exposure to powdered neem leaf, but it took 120 hours to reach the same level of larval mortality in aqueous leaf extract. The crude extract slowly inhibited the growth and development of mosquitoes while the crude powder acted more as a barrier; the mosquitoes probably died from suffocation. However, both types of preparations can be made and used by local people to control mosquito breeding in anthropogenic habitats, especially in urbanized areas.

  19. European Aedes albopictus and Culex pipiens Are Competent Vectors for Japanese Encephalitis Virus.

    Science.gov (United States)

    de Wispelaere, Mélissanne; Desprès, Philippe; Choumet, Valérie

    2017-01-01

    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.

  20. Differential Infectivities among Different Japanese Encephalitis Virus Genotypes in Culex quinquefasciatus Mosquitoes.

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    Yan-Jang S Huang

    2016-10-01

    Full Text Available During the last 20 years, the epidemiology of Japanese encephalitis virus (JEV has changed significantly in its endemic regions due to the gradual displacement of the previously dominant genotype III (GIII with clade b of GI (GI-b. Whilst there is only limited genetic difference distinguishing the two GI clades (GI-a and GI-b, GI-b has shown a significantly wider and more rapid dispersal pattern in several regions in Asia than the GI-a clade, which remains restricted in its geographic distribution since its emergence. Although previously published molecular epidemiological evidence has shown distinct phylodynamic patterns, characterization of the two GI clades has only been limited to in vitro studies. In this study, Culex quinquefasciatus, a known competent JEV mosquito vector species, was orally challenged with three JEV strains each representing GI-a, GI-b, and GIII, respectively. Infection and dissemination were determined based on the detection of infectious viruses in homogenized mosquitoes. Detection of JEV RNA in mosquito saliva at 14 days post infection indicated that Cx. quinquefasciatus can be a competent vector species for both GI and GIII strains. Significantly higher infection rates in mosquitoes exposed to the GI-b and GIII strains than the GI-a strain suggest infectivity in arthropod vectors may lead to the selective advantage of previously and currently dominant genotypes. It could thus play a role in enzootic transmission cycles for the maintenance of JEV if this virus were ever to be introduced into North America.

  1. Bioefficacy of acyclic monoterpenes and their saturated derivatives against the West Nile vector Culex pipiens.

    Science.gov (United States)

    Michaelakis, Antonios; Vidali, Veroniki P; Papachristos, Dimitrios P; Pitsinos, Emmanuel N; Koliopoulos, George; Couladouros, Elias A; Polissiou, Moschos G; Kimbaris, Athanasios C

    2014-02-01

    Twenty acyclic monoterpenes with different functional groups (acetoxy, hydroxyl, carbonyl and carboxyl) bearing a variable number of carbon double bonds were assayed as repellent and larvicidal agents against the West Nile vector Culex pipiens. Seven of them were derivatives that were synthesized through either hydrogenation or oxidation procedures. All repellent compounds were tested at the dose of 1mgcm(-2) and only neral and geranial were also tested at a 4-fold lower dose (0.25mgcm(-2)). Repellency results revealed that geranial, neral, nerol, citronellol, geranyl acetate and three more derivatives dihydrolinalool (3), dihydrocitronellol (5) and dihydrocitronellyl acetate (6) resulted in no landings. Based on the LC50 values the derivative dihydrocitronellyl acetate (6) was the most active of all, resulting in an LC50 value of 17.9mgL(-1). Linalyl acetate, citronellyl acetate, neryl acetate, geranyl acetate, dihydrocitronellol (5), dihydrocitronellal (7), citronellol, dihydrolinalyl acetate (2), citronellic acid and tetrahydrolinalyl acetate (1) were also toxic with LC50 values ranging from 23 to 45mgL(-1). Factors modulating toxicity have been identified, thus providing information on structural requirements for the selected acyclic monoterpenes. The acetoxy group enhanced toxicity, without being significantly affected by the unsaturation degree. Within esters, reduction of the vinyl group appears to decrease potency. Presence of a hydroxyl or carbonyl group resulted in increased activity but only in correlation to saturation degree. Branched alcohols proved ineffective compared to the corresponding linear isomers. Finally, as it concerns acids, data do not allow generalizations or correlations to be made.

  2. Larvicidal activity of medicinal plant extracts against Anopheles subpictus & Culex tritaeniorhynchus

    Science.gov (United States)

    Kamaraj, C.; Bagavan, A.; Elango, G.; Zahir, A. Abduz; Rajakumar, G.; Marimuthu, S.; Santhoshkumar, T.; Rahuman, A. Abdul

    2011-01-01

    Background & objectives: Mosquitoes transmit serious human diseases, causing millions of deaths every year and the development of resistance to chemical insecticides resulting in rebounding vectorial capacity. Plants may be alternative sources of mosquito control agents. The present study assessed the role of larvicidal activities of hexane, chloroform, ethyl acetate, acetone, and methanol dried leaf and bark extracts of Annona squamosa L., Chrysanthemum indicum L., and Tridax procumbens L. against the fourth instar larvae of malaria vector, Anopheles subpictus Grassi and Japanese encephalitis vector, Culex tritaeniorhynchus Giles (Diptera: Culicidae). Methods: Larvicidal activities of three medicinal plant extracts were studied in the range of 4.69 to 1000 mg/l in the laboratory bioassays against early 4th instar larvae of An. subpictus and Cx. tritaeniorhynchus. The mortality data were subjected to probit analysis to determine the lethal concentrations (LC50 and LC90) to kill 50 and 90 per cent of the treated larvae of the respective species. Results: All plant extracts showed moderate effects after 24 h of exposure; however, the highest toxic effect of bark methanol extract of A. squamosa, leaf ethyl acetate extract of C. indicum and leaf acetone extract of T. procumbens against the larvae of An. subpictus (LC50 = 93.80, 39.98 and 51.57 mg/l) and bark methanol extract of A. squamosa, leaf methanol extract of C. indicum and leaf ethyl acetate extract of T. procumbens against the larvae of Cx. tritaeniorhynchus (LC50 =104.94, 42.29 and 69.16 mg/l) respectively. Interpretation & Conclusions: Our data suggest that the bark ethyl acetate and methanol extract of A. squamosa, leaf ethyl acetate and methanol extract of C. indicum, acetone and ethyl acetate extract of T. procumbens have the potential to be used as an ecofriendly approach for the control of the An. subpictus, and Cx. tritaeniorhynchus. PMID:21808141

  3. Identification of the temperature- induced larvicidal efficacy of Agave angustifolia against Aedes, Culex and Anopheles larvae

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    Mithilesh eKajla

    2016-01-01

    Full Text Available Synthetic insecticides are generally employed to control the mosquito population. However, their injudicious over usage and non-biodegradability are associated with many adverse effects on the environment and mosquitoes. The application of environment-friendly mosquitocidals might be an alternate to overcome these issues. In this study, we found that organic or aqueous extracts of Agave angustifolia leaves exhibited a strong larvicidal activity (LD50 28.27 µg/ml against Aedes aegypti, Culex quinquefasciatus and Anopheles stephensi larvae within a short exposure of 12h. The larvicidal activity of Agave angustifolia is inherited and independent of the plants vegetative growth. Interestingly, the plant larvicidal activity was observed exclusively during the summer season (April-August, when outside temperature is between 30oC to 50oC and it was significantly reduced during winter season (December-February, when the outside temperature falls to ~4oC or lower. Thus, we hypothesized that the larvicidal components of Agave angustifolia might be induced by the manipulation of environmental temperature and should be resistant to the hot conditions. We found that the larvicidal activity of Agave angustifolia was induced when plants were maintained at 37oC in a semi-natural environment against the controls that were growing outside in cold weather. Pre-incubation of Agave angustifolia extract at 100oC for 1h killed 60% larvae in 12h, which gradually increased to 100% mortality after 24h. In addition, the dry powder formulation of Agave angustifolia, also displayed a strong larvicidal activity after a long shelf life. Together, these findings revealed that Agave angustifolia is an excellent source of temperature induced bioactive metabolites that may assist the preparedness for vector control programs competently.

  4. Pterodon emarginatus oleoresin-based nanoemulsion as a promising tool for Culex quinquefasciatus (Diptera: Culicidae) control.

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    Oliveira, Anna E M F M; Duarte, Jonatas L; Cruz, Rodrigo A S; Souto, Raimundo N P; Ferreira, Ricardo M A; Peniche, Taires; da Conceição, Edemilson C; de Oliveira, Leandra A R; Faustino, Silvia M M; Florentino, Alexandro C; Carvalho, José C T; Fernandes, Caio P

    2017-01-03

    Preparation of nanoformulations using natural products as bioactive substances is considered very promising for innovative larvicidal agents. On this context, oil in water nanoemulsions develop a main role, since they satisfactorily disperse poor-water soluble substances, such as herbal oils, in aqueous media. Pterodon emarginatus, popularly known as sucupira, has a promising bioactive oleoresin. However, to our knowledge, no previous studies were carried out to evaluate its potential against Culex quinquefasciatus, the main vector of the tropical neglected disease called lymphatic filariasis or elephantiasis. Thus, we aimed to investigate influence of different pairs of surfactants in nanoemulsion formation and investigate if a sucupira oleoresin-based nanoemulsion has promising larvicidal activity against this C. quinquefasciatus. We also evaluated morphological alteration, possible mechanism of insecticidal action and ecotoxicity of the nanoemulsion against a non-target organism. Among the different pairs of surfactants that were tested, nanoemulsions obtained with polysorbate 80/sorbitan monooleate and polysorbate 80/sorbitan trioleate presented smallest mean droplet size just afterwards preparation, respectively 151.0 ± 2.252 and 160.7 ± 1.493 nm. They presented high negative zeta potential values, low polydispersity index (algae Chlorella vulgaris at low concentration (25 mg/L). Our results suggest that optimal nanoemulsions may be prepared with different surfactants using a low cost and low energy simple method. Moreover, this prototype proved to be effective against C. quinquefasciatus, being considered an ecofriendly novel nanoproduct that can be useful in integrated control programs of vector control.

  5. Multiple Insecticide Resistances in the Disease Vector Culex p. Quinquefasciatus from Western Indian Ocean

    Science.gov (United States)

    Pocquet, Nicolas; Milesi, Pascal; Makoundou, Patrick; Unal, Sandra; Zumbo, Betty; Atyame, Célestine; Darriet, Frédéric; Dehecq, Jean-Sébastien; Thiria, Julien; Bheecarry, Ambicadutt; Iyaloo, Diana P.; Weill, Mylène; Chandre, Fabrice; Labbé, Pierrick

    2013-01-01

    Several mosquito-borne diseases affect the Western Indian Ocean islands. Culex pipiens quinquefasciatus is one of these vectors and transmits filariasis, Rift Valley and West Nile viruses and the Japanese encephalitis. To limit the impact of these diseases on public health, considerable vector control efforts have been implemented since the 50s, mainly through the use of neurotoxic insecticides belonging to Organochlorines (OC), Organophosphates (OP) and pyrethroids (PYR) families. However, mosquito control failures have been reported on site, and they were probably due to the selection of resistant individuals in response to insecticide exposure. In this study, we used different approaches to establish a first regional assessment of the levels and mechanisms of resistance to various insecticides. Bioassays were used to evaluate resistance to various insecticides, enzyme activity was measured to assess the presence of metabolic resistances through elevated detoxification, and molecular identification of known resistance alleles was investigated to determine the frequency of target-site mutations. These complementary approaches showed that resistance to the most used insecticides families (OC, OP and PYR) is widespread at a regional scale. However, the distribution of the different resistance genes is quite heterogeneous among the islands, some being found at high frequencies everywhere, others being frequent in some islands and absent in others. Moreover, two resistance alleles displayed clinal distributions in Mayotte and La Réunion, probably as a result of a heterogeneous selection due to local treatment practices. These widespread and diverse resistance mechanisms reduce the capacity of resistance management through classical strategies (e.g. insecticide rotation). In case of a disease outbreak, it could undermine the efforts of the vector control services, as only few compounds could be used. It thus becomes urgent to find alternatives to control populations

  6. Characterization of Culex pipiens Complex (Diptera: Culicidae) Populations in Colorado, USA Using Microsatellites

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    Kothera, Linda; Godsey, Marvin S.; Doyle, Michael S.; Savage, Harry M.

    2012-01-01

    Mosquitoes such as those in the Culex pipiens complex are important vectors of disease. This study was conducted to genetically characterize Cx. pipiens complex populations in the state of Colorado, USA, and to determine the number of genetic clusters represented by the data. Thirteen populations located among four major river basins were sampled (n = 597 individuals) using a panel of 14 microsatellites. The lowest-elevation sites had the highest Expected Heterozygosity (HE) values (range 0.54–0.65). AMOVA results indicated the presence of statistically significant amounts of variation within each level when populations were analyzed as one group or when they were grouped either by river basin or by their position on the east or west side of the Rocky Mountains. Most pairwise FST values were significant via permutation test (range 0–0.10), with the highest values from comparisons with Lamar, in southeast CO. A neighbor joining tree based on Cavalli–Sforza and Edwards’s chord distances was consistent with the geographic locations of populations, as well as with the AMOVA results. There was a significant isolation by distance effect, and the cluster analysis resolved five groups. Individuals were also assayed with an additional microsatellite marker, Cxpq78, proposed to be monomorphic in Cx. pipiens but polymorphic in the closely related but biologically distinct species Cx. quinquefasciatus. Low frequencies (≤3%) of Cx. quinquefasciatus alleles for this marker were noted, and mostly confined to populations along the Interstate 25 corridor. Pueblo was distinct in that it had 10% Cx. quinquefasciatus alleles, mostly of one allele size. The degree of population genetic structure observed in this study is in contrast with that of Cx. tarsalis, the other major vector of WNV in the western U.S., and likely reflects the two species’ different dispersal strategies. PMID:23094068

  7. "Singing in the Tube"--audiovisual assay of plant oil repellent activity against mosquitoes (Culex pipiens).

    Science.gov (United States)

    Adams, Temitope F; Wongchai, Chatchawal; Chaidee, Anchalee; Pfeiffer, Wolfgang

    2016-01-01

    Plant essential oils have been suggested as a promising alternative to the established mosquito repellent DEET (N,N-diethyl-meta-toluamide). Searching for an assay with generally available equipment, we designed a new audiovisual assay of repellent activity against mosquitoes "Singing in the Tube," testing single mosquitoes in Drosophila cultivation tubes. Statistics with regression analysis should compensate for limitations of simple hardware. The assay was established with female Culex pipiens mosquitoes in 60 experiments, 120-h audio recording, and 2580 estimations of the distance between mosquito sitting position and the chemical. Correlations between parameters of sitting position, flight activity pattern, and flight tone spectrum were analyzed. Regression analysis of psycho-acoustic data of audio files (dB[A]) used a squared and modified sinus function determining wing beat frequency WBF ± SD (357 ± 47 Hz). Application of logistic regression defined the repelling velocity constant. The repelling velocity constant showed a decreasing order of efficiency of plant essential oils: rosemary (Rosmarinus officinalis), eucalyptus (Eucalyptus globulus), lavender (Lavandula angustifolia), citronella (Cymbopogon nardus), tea tree (Melaleuca alternifolia), clove (Syzygium aromaticum), lemon (Citrus limon), patchouli (Pogostemon cablin), DEET, cedar wood (Cedrus atlantica). In conclusion, we suggest (1) disease vector control (e.g., impregnation of bed nets) by eight plant essential oils with repelling velocity superior to DEET, (2) simple mosquito repellency testing in Drosophila cultivation tubes, (3) automated approaches and room surveillance by generally available audio equipment (dB[A]: ISO standard 226), and (4) quantification of repellent activity by parameters of the audiovisual assay defined by correlation and regression analyses.

  8. Resistance in the mosquito, Culex quinquefasciatus, and possible mechanisms for resistance.

    Science.gov (United States)

    Xu, Qiang; Liu, Huqi; Zhang, Lee; Liu, Nannan

    2005-11-01

    Two mosquito strains of Culex quinquefasciatus (Say), MAmCq(G0) and HAmCq(G0), were collected from Mobile and Huntsville, Alabama, respectively. MAmCq(G0) and HAmCq(G0) were further selected in the laboratory with permethrin for one and three generations, respectively. The levels of resistance to permethrin in MAmCq(G1) (after one-generation selection) and HAmCq(G3) (after three-generation selection) increased rapidly. Resistance to permethrin in MAmCq(G1) and HAmCq(G3) was partially suppressed by piperonyl butoxide (PBO), S,S,S-tributylphosphorotrithioate (DEF) and diethyl maleate (DEM), inhibitors of cytochrome P450 monooxygenases, hydrolases and glutathione S-transferases (GST), respectively, suggesting these three enzyme families are important in conferring permethrin resistance in both strains. A substitution of leucine to phenylalanine (L to F) resulting from a single nucleotide polymorphism (SNP), termed the kdr mutation, in the para-homologous sodium channel gene has been reported as a very common mutation associated with pyrethroid resistance of insects. A 341-bp sodium channel gene fragment, where the kdr mutation resides, was generated by PCR from genomic DNAs of Cx. quinquefasciatus strains. We found that the kdr mutation was present in both permethrin-selected and unselected HAmCq and MAmCq mosquito populations, suggesting that the kdr mutation plays the role in permethrin resistance. There was no significant change in the frequency and heterozygosity of the A to T SNP for the kdr allele between permethrin-selected and unselected MAmCq and HAmCq mosquitoes, indicating that other mechanisms are involved in the evolution of resistance in mosquitoes selected by permethrin in the laboratory. Copyright 2005 Society of Chemical Industry.

  9. Olfactory responses of the antennal trichoid sensilla to chemical repellents in the mosquito, Culex quinquefasciatus.

    Science.gov (United States)

    Liu, Feng; Chen, Li; Appel, Arthur G; Liu, Nannan

    2013-11-01

    Insect repellents are widely used to protect against insect bites and thus prevent allergic reaction and the spread of disease. To gain insight into the mosquito's response to chemicals repellents, we investigated the interaction between the olfactory system of the mosquito Culex quinquefasciatus Say and chemical repellents using single sensillum recording. The interactions of 50 repellent chemicals with olfactory receptor neurons were measured in six different types of mosquito sensilla: long sharp trichoid (LST), short sharp trichoid (SST), short blunt trichoid I (SBT-I), short blunt trichoid II (SBT-II), short blunt trichoid-curved (SBT-C), and grooved peg (GP). A single olfactory neuron reacted to the chemical repellents in each of the sensilla except for SBT-I and SBT-II, where two neurons were involved. Other than LST and GP, which showed no or very weak responses to the repellents tested, all the sensilla showed significant excitatory responses to certain types of repellents. Terpene-derived chemicals such as eucalyptol, α-pinene, and camphor, stimulated olfactory receptor neurons in a dose-dependent manner and mosquitoes responded more strongly to terpene-derived chemical repellents than to non-terpene-derived chemicals such as dimethyl phthalate. Mosquitoes also exhibited a similar response to stereoisomers of chemicals such as (-)-β-pinene versus (+)-β-pinene, and (-)-menthone versus (+)-menthone. This study not only demonstrates the effects of chemical repellents on the mosquito olfactory system but also provides important information that will assist those screening new mosquito repellents and designing new mosquito control agents.

  10. Profiles of Amino Acids and Acylcarnitines Related with Insecticide Exposure in Culex quinquefasciatus (Say)

    Science.gov (United States)

    Martin-Park, Abdiel; Gomez-Govea, Mayra A.; Lopez-Monroy, Beatriz; Treviño-Alvarado, Víctor Manuel; Torres-Sepúlveda, María del Rosario; López-Uriarte, Graciela Arelí; Villanueva-Segura, Olga Karina; Ruiz-Herrera, María del Consuelo; Martinez-Fierro, Margarita de la Luz; Delgado-Enciso, Ivan; Flores-Suárez, Adriana E.; White, Gregory S.; Martínez de Villarreal, Laura E.; Ponce-Garcia, Gustavo; Black, William C.; Rodríguez-Sanchez, Irám Pablo

    2017-01-01

    Culex quinquefasciatus Say is a vector of many pathogens of humans, and both domestic and wild animals. Personal protection, reduction of larval habitats, and chemical control are the best ways to reduce mosquito bites and, therefore, the transmission of mosquito-borne pathogens. Currently, to reduce the risk of transmission, the pyrethroids, and other insecticide groups have been extensively used to control both larvae and adult mosquitoes. In this context, amino acids and acylcarnitines have never been associated with insecticide exposure and or insecticide resistance. It has been suggested that changes in acylcarnitines and amino acids profiles could be a powerful diagnostic tool for metabolic alterations. Monitoring these changes could help to better understand the mechanisms involved in insecticide resistance, complementing the strategies for managing this phenomenon in the integrated resistance management. The purpose of the study was to determine the amino acids and acylcarnitines profiles in larvae of Cx. quinquefasciatus after the exposure to different insecticides. Bioassays were performed on Cx. quinquefasciatus larvae exposed to the diagnostic doses (DD) of the insecticides chlorpyrifos (0.001 μg/mL), temephos (0.002 μg/mL) and permethrin (0.01 μg/mL). In each sample, we analyzed the profile of 12 amino acids and 31 acylcarnitines by LC-MS/MS. A t-test was used to determine statistically significant differences between groups and corrections of q-values. Results indicates three changes, the amino acids arginine (ARG), free carnitine (C0) and acetyl-carnitine (C2) that could be involved in energy production and insecticide detoxification. We confirmed that concentrations of amino acids and acylcarnitines in Cx. quinquefasciatus vary with respect to different insecticides. The information generated contributes to understand the possible mechanisms and metabolic changes occurring during insecticide exposure. PMID:28085898

  11. Efficacy of two formulations of the bioinsecticide spinosad against Culex quinquefasciatus in India.

    Science.gov (United States)

    Sadanandane, C; Boopathi Doss, P S; Jambulingam, P; Zaim, M

    2009-03-01

    Spinosad 12% suspension concentrate (SC) and 0.5% granular (G) formulations were tested against Culex quinquefasciatus immatures at 3 dosages--50, 100, and 150 mg active ingredient (AI)/m2--in cesspits, street drains, and disused wells in comparison with temephos 1% G at 1 part per million. The 2 formulations reduced the density of pupae of Cx. quinquefasciatus by 80-100% for 7-14 days in cesspits, 7-18 days in drains, and 33-69 days in disused wells at the 3 dosages tested. The 12% SC and 0.5% G formulations were equally effective in suppressing the larval and pupal populations of Cx. quinquefasciatus in all the habitats treated. At 100 mg AI/m2 in drains and cesspits, the efficacy of spinosad 0.5% G was greater than that of temephos (1% G) and that of spinosad 12% SC was comparable to that of temephos (1% G) applied to the 2 habitats. In disused wells, both the formulations lasted longer than temephos. Based on the small-scale trial, the rate of 150 mg AI/m2 of spinosad was selected for field application to cesspits and drains and 50 mg AI/m2 for application to disused wells. The efficacy observed in medium-scale trials was in agreement with that of small-scale trials. The trial showed that the 2 formulations of spinosad can be used for larval control of Cx. quinquefasciatus, at 50 mg AI/m2, applied at weekly intervals to cesspits and street drains and at monthly intervals to disused wells. At the higher dose of 150 mg AI/m2, the 2 formulations were effective in suppressing the pupal population for 2 wk in cesspits and street drains and for 2 months in disused wells.

  12. Residential characteristics aggravating infestation by Culex quinquefasciatus in a region of Northeastern Brazil

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    Juliana Cavalcanti Correia

    2012-12-01

    Full Text Available OBJECTIVE: Analyse how basic sanitation conditions, water supply and housing conditions affect the concentration of Culex quinquefasciatus METHODS: Populations of C. quinquefasciatus in 61 houses in the municipality of Olinda, PE, were monitored between October 2009 and October 2010. Observations were carried out in homes without the presence of preferred breeding sites in order to identify characteristics that may be aggravating factors for the development of the mosquito. Five aggravating factors were analysed: vegetation cover surrounding the home, number of residents/home, water storage, sewage drainage and water drainage. These characteristics were analysed in terms of presence or absence and as indicators of the degree of infestation, which was estimated through monitoring the concentration of eggs (oviposition traps - BR-OVT and adults (CDC light traps. RESULTS: Sewage drainage to a rudimentary septic tank or to the open air was the most frequent aggravating factor in the homes (91.8%, although the presence of vegetation was the only characteristic that significantly influenced the increase in the number of egg rafts (p = 0.02. The BR-OVT achieved positive results in 95.1% of the evaluations, with the presence of at least one egg raft per month. A total of 2,366 adults were caught, with a mosquito/room/night ratio of 32.9. No significant difference was found in the number of mosquitoes caught in the homes. CONCLUSIONS: Although the sanitation and water supply influence the population density of C. quinquefasciatus, residence features that are not usually considered in control measures can be aggravating factors in sustaining the mosquito population.

  13. Larval Habitat Substrates Could Affect the Biology and Vectorial Capacity of Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Shah, Rizwan Mustafa; Ali, Qasim; Alam, Mehboob; Shad, Sarfraz Ali; Majeed, Shahid; Riaz, Muhammad; Binyameen, Muhammad

    2017-05-01

    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: journals.permissions@oup.com.

  14. TOXICITY OF EUPATORIUM CANNABINUM L. AGAINST SECOND AND FOURTH INSTAR LARVAE OF CULEX QUINQUEFASCIATUS AND AEDES AEGYPTI

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    Arshed Iqbal Dar

    2013-02-01

    Full Text Available The aim of the study was to demonstrate the toxicity of Eupatorium cannabinum L. against 2nd and 4th instar larvae of Culex quinquefasciatus and Aedes aegypti. For growth inhibitory activities early 2nd instar and 4th instar of Culex were taken in 500 ml capacitor glass beakers each beaker containing 25 larvae of 2nd and 4th instar separately. The beaker contains 240 ml water and 1 ml of test concentration of Eupatorium extract. Four different concentration regions from 20 to 50 ppm concentration were used. Each concentration has three replicates with one control and one untreated group. The following observations were recorded and growth inhibitory activities were photographed. Toxicity of acetone extract of Eupatorium cannabinum L. was observed against 2nd and 4th instar larvae of Aedes aegypti when four different concentrations were taken along with a control and uncontrolled group in three replicates, it was noticed that larval motility was dose dependent; as the dose concentration increases the mortality also increases. With the view to discourage further aggravation of environmental pollution through the use of synthetic insecticides, it is imperative to explore the abundant natural plant resources and replace the intrinsically hazardous chemicals through natural plant products not only to combat malaria but also precious human life from the ill effects of the synthetic chemicals.

  15. Synergistic Activity Between S-Layer Protein and Spore-Crystal Preparations from Lysinibacillus sphaericus Against Culex quinquefasciatus Larvae.

    Science.gov (United States)

    Lozano, Lucía C; Dussán, Jenny

    2017-03-01

    Lysinibacillus sphaericus is used for the biological control of mosquitoes. The main toxicity mechanism of pathogenic strains is a binary toxin produced during sporulation. S-layer is a proteinaceous structure on the surface of bacteria; its functions have been involved in the interaction between bacterial cells and the environment, for example, as protective coats, surface recognition, and biological control. In L. sphaericus, S-layer protein (SlpC) is expressed in vegetative cells, and is also found in spore-crystal preparations; it has larvicidal activity in Culex spp. In this study, partial and completed sporulated culture toxicities were compared; also, S-layer protein and spore-crystal proteins were tested against Culex quinquefasciatus larvae for possible interactions. Larvicidal activity obtained with a combination of SlpC and spore-crystal proteins from strain III(3)7 showed no significant interaction, whereas, combinations of both preparations from strain 2362 showed synergistic effect. The highest synergistic activity observed was between spore protein complex from strain 2362 and SlpC from III(3)7. S-layer protein could be considered a good alternative in formulation improvement, for biological control of mosquitoes.

  16. Monitoring temporal fluctuations of Culex quinquefasciatus using oviposition traps containing attractant and larvicide in an urban environment in Recife, Brazil.

    Science.gov (United States)

    Barbosa, Rosângela Maria Rodrigues; Regis, Lêda Narcisa

    2011-06-01

    The use of attractants and larvicides in oviposition traps is of practical interest for the surveillance and control of urban mosquitoes. In addition to increasing the safety of the traps, this combination is essential for an attract-and-kill control strategy based on trapping mosquito eggs. The combination of Bacillus thuringiensis var. israelensis (Bti) and grass infusion (GI) vs. GI alone were tested for their ability to attract in paired BR-OVT traps in the backyards of 10 houses in Recife, Brazil, for a period of 45 days. Results show that females prefer to oviposit in traps containing Bti (363 compared with 251 egg rafts over 45 days). Results from a one-year trial on the efficacy of BR-OVT traps loaded with GI and Bti as a sampling tool to monitor temporal fluctuations in the population densities of Culex quinquefasciatus in an urban environment are also reported. From December 2006-January 2007, one trap per home was installed and maintained for 348 consecutive days in 134-151 houses located in three urban blocks. Throughout the one-year field trial a total of 43,151 Culex egg rafts were collected in the traps. The data show that BR-OVT loaded with GI and Bti is sensitive enough to demonstrate continuous reproductive activity of Cux. quinquefasciatus in the study area throughout the year and to monitor temporal fluctuations in population density.

  17. Monitoring temporal fluctuations of Culex quinquefasciatus using oviposition traps containing attractant and larvicide in an urban environment in Recife, Brazil

    Directory of Open Access Journals (Sweden)

    Rosângela Maria Rodrigues Barbosa

    2011-06-01

    Full Text Available The use of attractants and larvicides in oviposition traps is of practical interest for the surveillance and control of urban mosquitoes. In addition to increasing the safety of the traps, this combination is essential for an attract-and-kill control strategy based on trapping mosquito eggs. The combination of Bacillus thuringiensis var. israelensis (Bti and grass infusion (GI vs. GI alone were tested for their ability to attract in paired BR-OVT traps in the backyards of 10 houses in Recife, Brazil, for a period of 45 days. Results show that females prefer to oviposit in traps containing Bti (363 compared with 251 egg rafts over 45 days. Results from a one-year trial on the efficacy of BR-OVT traps loaded with GI and Bti as a sampling tool to monitor temporal fluctuations in the population densities of Culex quinquefasciatus in an urban environment are also reported. From December 2006-January 2007, one trap per home was installed and maintained for 348 consecutive days in 134-151 houses located in three urban blocks. Throughout the one-year field trial a total of 43,151 Culex egg rafts were collected in the traps. The data show that BR-OVT loaded with GI and Bti is sensitive enough to demonstrate continuous reproductive activity of Cux. quinquefasciatus in the study area throughout the year and to monitor temporal fluctuations in population density.

  18. Effects of heavy metals on population growth and metallothionein gene expression in the mosquito Culex quinquefasciatus, from Calcutta, India

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Sagartirtha; Duttagupta, Asish K.; Mal, Tarun K

    2004-01-01

    Major water bodies in and around the city of Calcutta (India) receive heavy metal contaminated effluents from industries, households, and vehicular traffic through sewage or drainage. We quantified concentrations of Cu, Zn, and Cd from three water bodies at Kalighat, Tangra, and VIP Road, respectively. The concentrations of these heavy metals were significantly greater in the summer than in monsoon when heavy downpours resulted in reduced metal concentrations. Concentrations of metals in the mosquito Culex quinquefasciatus also reflected such seasonal fluctuations. Hatchability and survivorship of C. quinquefasciatus significantly differed among the sites and were reduced significantly from the control. Exposure to heavy metals also induced MT-gene expression in C. quinquefasciatus, likely helping them to survive in the water bodies stressed with heavy metals. MT-gene activity demonstrated significant variation among sites and seasons with the highest activity in the summer in the VIP Road population. This study suggests that C. quinquefasciatus could be used as an ecological indicator of heavy metal pollution by monitoring its MT-gene expression. - The mosquito, Culex quinquefasciatus, might be useful as an indicator of trace metals.

  19. Evolutionary genomics of Culex pipiens: global and local adaptations associated with climate, life-history traits and anthropogenic factors.

    Science.gov (United States)

    Asgharian, Hosseinali; Chang, Peter L; Lysenkov, Sergey; Scobeyeva, Victoria A; Reisen, William K; Nuzhdin, Sergey V

    2015-07-07

    We present the first genome-wide study of recent evolution in Culex pipiens species complex focusing on the genomic extent, functional targets and likely causes of global and local adaptations. We resequenced pooled samples of six populations of C. pipiens and two populations of the outgroup Culex torrentium. We used principal component analysis to systematically study differential natural selection across populations and developed a phylogenetic scanning method to analyse admixture without haplotype data. We found evidence for the prominent role of geographical distribution in shaping population structure and specifying patterns of genomic selection. Multiple adaptive events, involving genes implicated with autogeny, diapause and insecticide resistance were limited to specific populations. We estimate that about 5-20% of the genes (including several histone genes) and almost half of the annotated pathways were undergoing selective sweeps in each population. The high occurrence of sweeps in non-genic regions and in chromatin remodelling genes indicated the adaptive importance of gene expression changes. We hypothesize that global adaptive processes in the C. pipiens complex are potentially associated with South to North range expansion, requiring adjustments in chromatin conformation. Strong local signature of adaptation and emergence of hybrid bridge vectors necessitate genomic assessment of populations before specifying control agents.

  20. Efficacy of agnique (mmf) monomolecular surface film against immature stages of Anopheles arabiensis patton and Culex spp (diptera: culicidae) in Khartoum, Sudan.

    Science.gov (United States)

    Bashir, Al; Hassan, A Abu; Salmah, M R Che; Rahman, W A

    2008-03-01

    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.

  1. Larvicidal and pupicidal properties of Acalypha alnifolia Klein ex Willd. (Euphorbiaceae) leaf extract and the microbial insecticide Metarhizium anisopliae (Metsch.) against lymphatic filarial vector, Culex quinquefasciatus..

    Science.gov (United States)

    This study was made to determine the mosquitocidal properties of Acalypha alnifolia leaf extract combined with the use of Metarizhium anisopliae spores for control of the lymphatic filariasis vector Culex quinquefasciatus. The methanolic leaf extract showed larvicidal and pupicidal effects after 24...

  2. Larvicidal and pupicidal properties of Acalypha alnifolia Klein ex willd.(Euphorbiaceae) leaf extract and the microbial insecticide Metarhizium anisopliae (Metsch.) against lymphatic filarial vector, Culex quinquefasciatus Sa

    Science.gov (United States)

    This study was made to determine the mosquitocidal properties of Acalypha alnifolia leaf extract combined with the use of Metarizhium anisopliae spores for control of the lymphatic filariasis vector Culex quinquefasciatus. The methanolic leaf extract showed larvicidal and pupicidal effects after 24...

  3. Laboratory Transmission of Japanese Encephalitis and West Nile Viruses by Molestus Form of Culex pipiens (Diptera: Culicidae) Collected in Uzbekistan in 2004

    Science.gov (United States)

    2006-02-01

    variety of incubation periods, the dissemination rate increased after 14-d extrinsic incubation and was 80% for those Cx. pipi - ens held for 16Ð25 d at...1983. The effect of laboratory colonization on the vector pathogen interactions of Egyptian Culex pipi - ens and Rift Valley fever virus. Am. J. Trop.Med

  4. Intragenomic variation in the second internal transcribed spacer of the ribosomal DNA of species of the genera Culex and Lutzia (Diptera: Culicidae).

    Science.gov (United States)

    Vesgueiro, Fabiana Tavares; Demari-Silva, Bruna; Malafronte, Rosely dos Santos; Sallum, Maria Anice Mureb; Marrelli, Mauro Toledo

    2011-02-01

    Culex is the largest genus of Culicini and includes vectors of several arboviruses and filarial worms. Many species of Culex are morphologically similar, which makes their identification difficult, particularly when using female specimens. To aid evolutionary studies and species distinction, molecular techniques are often used. Sequences of the second internal transcribed spacer (ITS2) of ribosomal DNA (rDNA) from 16 species of the genus Culex and one of Lutzia were used to assess their genomic variability and to verify their applicability in the phylogenetic analysis of the group. The distance matrix (uncorrected p-distance) that was obtained revealed intragenomic and intraspecific variation. Because of the intragenomic variability, we selected ITS2 copies for use in distance analyses based on their secondary structures. Neighbour-joining topology was obtained with an uncorrected p-distance. Despite the heterogeneity observed, individuals of the same species were grouped together and correlated with the current, morphology-based classification, thereby showing that ITS2 is an appropriate marker to be used in the taxonomy of Culex.

  5. Intragenomic variation in the second internal transcribed spacer of the ribosomal DNA of species of the genera Culex and Lutzia (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Fabiana Tavares Vesgueiro

    2011-02-01

    Full Text Available Culex is the largest genus of Culicini and includes vectors of several arboviruses and filarial worms. Many species of Culex are morphologically similar, which makes their identification difficult, particularly when using female specimens. To aid evolutionary studies and species distinction, molecular techniques are often used. Sequences of the second internal transcribed spacer (ITS2 of ribosomal DNA (rDNA from 16 species of the genus Culex and one of Lutzia were used to assess their genomic variability and to verify their applicability in the phylogenetic analysis of the group. The distance matrix (uncorrected p-distance that was obtained revealed intragenomic and intraspecific variation. Because of the intragenomic variability, we selected ITS2 copies for use in distance analyses based on their secondary structures. Neighbour-joining topology was obtained with an uncorrected p-distance. Despite the heterogeneity observed, individuals of the same species were grouped together and correlated with the current, morphology-based classification, thereby showing that ITS2 is an appropriate marker to be used in the taxonomy of Culex.

  6. Trial of spatial repellency of metofluthrin-impregnated paper strip against Anopheles and Culex in shelters without walls in Lombok, Indonesia.

    Science.gov (United States)

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

    2004-12-01

    Trials of metofluthrin-impregnated multilayer paper strips against mosquitoes in shelters with no walls were carried out at 3 sites in Lombok, Indonesia. Major reductions in human biting by Culex quinquefasciatus, Anopheles balabacensis, and An. sundaicus were achieved. The device is a very practical measure of preventing outdoor mosquito biting, with no need for electricity or heating to evaporate its active ingredient.

  7. Behavioural response of female Culex pipiens pallens to common host plant volatiles and synthetic blends.

    Science.gov (United States)

    Yu, Bao-Ting; Ding, Yan-Mei; Mo, Jian-Chu

    2015-11-17

    Most mosquito species need to obtain sugar from host plants. Little is known about the chemical cues that Culex pipiens pallens use during their orientation to nectar host plants. In this study, we investigated the behavioural responses of female Cx. pipiens pallens to common floral scent compounds and their blends. Behavioural responses of female Cx. pipiens pallens to 18 individual compounds at different concentrations were determined in the olfactometer bioassays. A synthetic blend composed of behaviourally active compounds was formulated, and its attractiveness to mosquitoes was tested. Several most attractive compounds constituted a reduced blend, and its attractiveness was tested against the solvent and the full blend, respectively. Mosquito response in the olfactometer was analyzed by comparing the percentages of mosquitoes caught in the two arms by χ(2) test (observed versus expected). Fifteen of the 18 compounds were attractive to female Cx. pipiens pallens in the dose-dependent bioassays, with the exception of β-pinene, acetophenone and nonanal. (68.00 ± 2.49) % mosquitoes responded to the full blend composed of these 15 compounds on their optimal doses when tested against the solvent, with the preference index at 46.11 ± 3.57. Six individual compounds whose preference indices were over 40 constituted the reduced blend, and it attracted (68.00 ± 1.33) % mosquitoes when tested against the solvent while its preference index was 42.00 ± 3.54. When tested against the full blend simultaneously in the olfactometer, the reduced blend could attract (45.00 ± 2.69) % of released mosquitoes, which was as attractive as the full blend. Our results demonstrate that female Cx. pipiens pallens is differentially attracted by a variety of compounds at different concentrations. Alteration of the concentration strongly affects the attractiveness of the synthetic blend. Several floral scent volatiles might be the universal olfactory cues for various

  8. Insecticidal and genotoxic activity of Psoralea corylifolia Linn. (Fabaceae) against Culex quinquefasciatus Say, 1823.

    Science.gov (United States)

    Dua, Virendra K; Kumar, Arvind; Pandey, Akhilesh C; Kumar, Sandeep

    2013-02-04

    Indiscriminate use of synthetic insecticides to eradicate mosquitoes has caused physiological resistance. Plants provide a reservoir of biochemical compounds; among these compounds some have inhibitory effect on mosquitoes. In the present study the larvicidal, adulticidal and genotoxic activity of essential oil of Psoralea corylifolia Linn. against Culex quinquefasciatus Say was explored. Essential oil was isolated from the seeds of P. corylifolia Linn. Larvicidal and adulticidal bioassay of Cx. quinquefasciatus was carried out by WHO method. Genotoxic activity of samples was determined by comet assay. Identification of different compounds was carried out by gas chromatography- mass spectrometry analysis. LC50 and LC90 values of essential oil were 63.38±6.30 and 99.02±16.63 ppm, respectively against Cx. quinquefasciatus larvae. The LD50 and LD90 values were 0.057±0.007 and 0.109±0.014 mg/cm2 respectively against adult Cx. quinquefasciatus,. Genotoxicity of adults was determined at 0.034 and 0.069 mg/cm2. The mean comet tail length was 6.2548±0.754 μm and 8.47±0.931 μm and the respective DNA damage was significant i.e. 6.713% and 8.864% in comparison to controls. GCMS analysis of essential oil revealed 20 compounds. The major eight compounds were caryophyllene oxide (40.79%), phenol,4-(3,7-dimethyl-3-ethenylocta-1,6-dienyl) (20.78%), caryophyllene (17.84%), α-humulene (2.15%), (+)- aromadendrene (1.57%), naphthalene, 1,2,3,4-tetra hydro-1,6-dimethyle-4-(1-methyl)-, (1S-cis) (1.53%), trans- caryophyllene (0.75%), and methyl hexadecanoate (0.67%). Essential oil obtained from the seeds of P. corylifolia showed potent toxicity against larvae and adult Cx. quinquefasciatus. The present work revealed that the essential oil of P. corylifolia could be used as environmentally sound larvicidal and adulticidal agent for mosquito control.

  9. Effects of microcosm scaling and food resources on growth and survival of larval Culex pipiens

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    Paradise Christopher J

    2001-08-01

    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

  10. Macrocyclops albidus (Copepoda: cyclopidae) for the Biocontrol of Aedes albopictus and Culex pipiens in Italy.

    Science.gov (United States)

    Veronesi, Rodolfo; Carrieri, Marco; Maccagnani, Bettina; Maini, Stefano; Bellini, Romeo

    2015-03-01

    The aim of our study was to assess the potential of Macrocyclops albidus as a biological control agent against the 1st and 2nd instars of Culex pipiens and Aedes albopictus. Under laboratory conditions of prey saturation (50 1st instars/copepod), an average of 58.98% of Cx. pipiens and 54.99% of Ae. albopictus larvae were killed by 1 copepod in 24 h. Trials run in big drums containing 200 liters of water showed that the M. albidus population, inoculated in April, efficiently controlled the mosquito population for the entire season. The predator was particularly effective against Ae. albopictus, as only 2 larvae of this species were found in the treated drums, compared to 814 larvae in untreated control drums throughout the study period. No difference was observed in the control efficacy between the 2 initial densities of copepods used. The reduction in Ae. albopictus density in the drums with 100 and 500 M. albidus with respect to the control drums was 99.90 ± 0.35% and 100.0 ± 0.0%, respectively. For Cx. pipiens, the reduction in density was 88.69 ± 13.51% and 84.65% in drums inoculated with 100 and 500 copepods, respectively. Macrocyclops albidus populations survived through the winter and continued to keep the mosquito population under control during the 2008 season. The M. albidus population developed very well both in drums placed in sunny and shaded areas and proved to be tolerant to both high (summer) and low (winter) temperatures. Trials performed on M. albidus survival in catch basins showed that after a few weeks, the copepod population dramatically decreased and subsequently disappeared. The main problem for copepod survival in catch basins seemed to be the low oxygen tension and accumulation of toxic substances, rather than copepods being flushed out in heavy rainfall episodes. During the period when copepods were present, they maintained the mosquito population under control; their partial disappearance from the catch basins, however, would

  11. Larvicidal activity of extracts from Ammi visnaga Linn. (Apiaceae) seeds against Culex quinquefasciatus Say. (Diptera: Culicidae).

    Science.gov (United States)

    Pavela, Roman; Vrchotová, Naděžda; Tříska, Jan

    2016-06-01

    Efficacies of the Ammi visnaga seeds extract and a majority of substances on larval Culex quinquefasciatus mortality in various development stages including pupae were studied. The effect of exposure time on larval mortality was also studied. The effect of sublethal concentrations or short exposure times on further larval development and subsequent fecundity in adults were studied as well. Lethal doses of the extract were estimated for the 2nd, 3rd and 4th instar of C. quinquefasciatus (LC50 for 18, 23 and 180 mg L(-1), respectively). The majority of furanochromenes, khellin and visnagin, were identified by analysing the extract. Khellin was significantly more effective compared to visnagin, whose LC50 was estimated at 8, 10 and 41 mg L(-1) for the 2nd, 3rd and 4th instar larvae. Khellin showed very fast efficacy on mortality for the 3rd instar larvae in a concentration of 100 mg L(-1). Fifty percent mortality was determined 30 min after application, a time which was considerably shorter compared to the extract (113 min) or visnagin (169 min). The effect of the application of lethal concentrations on C. quinquefasciatus larval mortality was studied. The least number of adults were hatched after application of the extract and khellin (41.8% and 37.9%, respectively), less than after visnagin application (46.7%) or in the control (94.2%). LC50 application caused lower fecundity in the hatched adults, lower hatchability of the eggs, and also very low natality, more than 77% lower for khellin compared to the control. A short exposure, corresponding to our estimated LT30, caused no significant acute toxicity in the larvae (until 24 h) for the extract or visnagin (4.3% and 11.5%, respectively); however, 18 min of action from khellin caused a 54.3% mortality rate of the larvae within 24 h.

  12. Seasonal dynamics of insecticide resistance, multiple resistance, and morphometric variation in field populations of Culex pipiens.

    Science.gov (United States)

    Taskin, Belgin Gocmen; Dogaroglu, Taylan; Kilic, Sercan; Dogac, Ersin; Taskin, Vatan

    2016-05-01

    Resistance to insecticides that impairs nervous transmission has been widely investigated in mosquito populations as insecticides are crucial to effective insect control. The development of insecticide resistance is also of special interest to evolutionary biologists since it represents the opportunity to observe the genetic consequences of a well-characterized alteration in the environment. Although the frequencies of resistance alleles in Culex pipiens populations against different groups of insecticides have been reported, no detailed information is available on the relative change in these allele frequencies over time. In this study, we collected mosquitoes of the Cx. pipiens complex from six locations in three seasons in the Aegean region of Turkey and examined the i) seasonal variations in resistance to four different chemical classes of insecticides, ii) seasonal fluctuations in frequencies of resistance-associated target-site mutations of the three genes (ace-1, kdr, and Rdl), and iii) potential seasonal variations in wing morphometric characters that may be modified in resistant mosquitoes. Our bioassay results indicated the presence of different levels of resistance to all tested insecticides for all three seasons in all locations. The results of the PCR-based molecular analysis revealed low frequencies of mutations in ace-1 and Rdl that are associated with resistance to malathion, bendiocarb, and dieldrin and no obvious seasonal changes. In contrast, we detected high frequencies and striking seasonal changes for two kdr mutations associated with resistance to DDT and pyrethroids. In addition, the evaluation of the field populations from all seasons in terms of the combinations of polymorphisms at four resistance-associated mutations did not reveal the presence of insects that are resistant to all pesticides. Results from the morphological analysis displayed a similar pattern for both wings and did not show a clear separation among the samples from the

  13. Vector competence of Aedes aegypti (L.) and Culex quinquefasciatus (Say) for Dirofilaria immitis (Leidy).

    Science.gov (United States)

    Tiawsirisup, Sonthaya; Nithiuthai, Suwannee

    2006-01-01

    This study was performed to examine the vector competence of Aedes aegypti and Culex quinquefasciatus for Dirofilaria immitis. Eleven individual experiments were conducted in this study. Nonthaburi and Udon Thani strains of Ae. aegypti were allowed to feed on infected dogs that had 5,750 and 4,600 microfilariae (mW) per ml of blood, respectively. Three groups of Bangkok-strain Cx. quinquefasciatus were allowed to feed on dogs that had 4,800, 5,200, and 5,850 mf per ml of blood. Six groups of Liverpool-strain Ae. aegypti were allowed to feed on dogs with 1,650, 1,950, 3,350, 9,000, 9,250, and 11,550 mf per ml of blood. Three to 4% of Nonthaburi-strain, and 0-6% of Udon Thani-strain Ae. aegypti became infected and had infective-stage larvae (L3) of D. immitis in their probosces. Zero to 1 and 7% of Bangkok-strain Cx. quinquefasciatus had L3 in their probosces after taking blood meals with 4,800 and 5,850 mf per ml of blood, respectively. The percent-infected Liverpool-strain Ae. aegypti with L3 in their probosces were 3-12, 0-12, 10, 16, 7-19, and 0-21 after taking blood meals with 1,650, 1,950, 3,350, 9,000, 9,250, and 11,550 mf per ml of blood, respectively, when tested at different post-blood-feeding days. This study showed both Ae. aegypti and Cx. quinquefasciatus from Thailand can become vectors for D. immitis; however, Liverpool-strain Ae. aegypti are more likely to be competent vectors for D. immitis than Ae. aegypti and Cx. quinquefasciatus from Thailand. The percent infection rates of Ae. aegypti and Cx. quinquefasciatus with D. immitis in the field in Thailand need to be investigated, to confirm the role of these mosquitoes in the life cycle of D. immitis in nature.

  14. Preliminary assessment of the potential role of urbanization in the distribution of carbamate and organophosphate resistant populations of Culex species in Ghana.

    Science.gov (United States)

    Kudom, Andreas A; Mensah, Ben A; Froeschl, Guenter; Boakye, Daniel; Rinder, Heinz

    2015-01-08

    Besides its role as a pathogen vector, Culex species also indirectly promotes the transmission of malaria if the use of bed nets or indoor residual spraying is discontinued due to a lack of insecticide efficacy against it. A recent survey revealed widespread occurrence of pyrethroid resistance among urban populations of this mosquito in Ghana. In order to plan and implement insecticide-based resistance management strategies, this study was carried out to assess resistance status of Culex species to organophosphate and carbamate in urban areas in Ghana and the possible mechanisms involved as well as environmental factors associated with its distribution. Mosquito larvae were sampled from various land use and ecological settings and in different seasons. In adults, susceptibility to organophosphates (fenitrothion, malathion) and carbamates (propoxur, bendiocarb) were determined. Mixed function oxidase (MFO) and α- and β-esterase assays, as well as a PCR diagnostic assay to determine ace1 mutation were performed in individual mosquitoes. Culex quinquefasciatus as well as C. decens and other unidentified Culex species were found breeding in polluted water bodies in the study sites. Across all sites and seasons, carbamate induced mortality was 94.1% ± 15.4 whereas mortality caused by organophosphate was 99.5% ± 2.2. In addition, ace1 mutation and high levels of esterases were detected in some of the mosquito populations. There was a strong correlation between susceptibility status of the mosquitoes and the level of absorbance of β-esterase (Pearson r=- 0.841, p=0.004). The study found low prevalence of resistance to carbamate and organophosphate insecticides among Culex species from Ghana. However, there were populations with ace1 mutations and high levels of esterases, which can confer high resistance to these classes of insecticides. Thus, it is important to monitor activities or behaviour that has the potential to select for carbamate and organophosphate

  15. Mosquito larvicidal, ovicidal, and repellent properties of botanical extracts against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Govindarajan, M; Mathivanan, T; Elumalai, K; Krishnappa, K; Anandan, A

    2011-08-01

    Mosquito-borne diseases have an economic impact, including loss in commercial and labor outputs, particularly in countries with tropical and subtropical climates; however, no part of the world is free from vector-borne diseases. In mosquito control programs, botanical origin may have the potential to be used successfully as eggs, larvae, and adult. The larvicidal, ovicidal, and repellent activities of crude benzene and ethyl acetate extracts of leaf of Ervatamia coronaria and Caesalpinia pulcherrima were assayed for their toxicity against three important vector mosquitoes, viz., Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae). The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in benzene extract of E. coronaria against the larvae of Anopheles Stephensi, Aedes aegypti, and Culex quinquefasciatus with the LC(50) and LC(90) values were 79.08, 89.59, and 96.15 ppm and 150.47, 166.04, and 174.10 ppm, respectively. Mean percent hatchability of the ovicidal activity was observed 48 h posttreatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. The leaf extract of E. coronaria was found to be most effective than Caesalpinia pulcherrima against eggs/egg rafts of three vector mosquitoes. For E. coronaria, the benzene extract exerted 300, 250, and 200 ppm against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus, respectively. The results of the repellent activity of benzene and ethyl acetate extract of E. coronaria and Caesalpinia pulcherrima plants at three different concentrations of 1.0, 2.5, and 5.0 mg/cm(2) were applied on skin of fore arm in man and exposed against adult female mosquitoes. In this observation, these two plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person, and also, the

  16. Role of Culex and Anopheles mosquito species as potential vectors of rift valley fever virus in Sudan outbreak, 2007

    Directory of Open Access Journals (Sweden)

    Galal Fatma H

    2010-03-01

    Full Text Available Abstract Background Rift Valley fever (RVF is an acute febrile arthropod-borne viral disease of man and animals caused by a member of the Phlebovirus genus, one of the five genera in the family Bunyaviridae. RVF virus (RVFV is transmitted between animals and human by mosquitoes, particularly those belonging to the Culex, Anopheles and Aedes genera. Methods Experiments were designed during RVF outbreak, 2007 in Sudan to provide an answer about many raised questions about the estimated role of vector in RVFV epidemiology. During this study, adult and immature mosquito species were collected from Khartoum and White Nile states, identified and species abundance was calculated. All samples were frozen individually for further virus detection. Total RNA was extracted from individual insects and RVF virus was detected from Culex, Anopheles and Aedes species using RT-PCR. In addition, data were collected about human cases up to November 24th, 2007 to asses the situation of the disease in affected states. Furthermore, a historical background of the RVF outbreaks was discussed in relation to global climatic anomalies and incriminated vector species. Results A total of 978 mosquitoes, belonging to 3 genera and 7 species, were collected during Sudan outbreak, 2007. Anopheles gambiae arabiensis was the most frequent species (80.7% in White Nile state. Meanwhile, Cx. pipiens complex was the most abundant species (91.2% in Khartoum state. RT-PCR was used and successfully amplified 551 bp within the M segment of the tripartite negative-sense single stranded RNA genome of RVFV. The virus was detected in female, male and larval stages of Culex and Anopheles species. The most affected human age interval was 15-29 years old followed by ≥ 45 years old, 30-44 years old, and then 5-14 years old. Regarding to the profession, housewives followed by farmers, students, shepherd, workers and the free were more vulnerable to the infection. Furthermore, connection between

  17. Role of Culex and Anopheles mosquito species as potential vectors of rift valley fever virus in Sudan outbreak, 2007.

    Science.gov (United States)

    Seufi, Alaaeddeen M; Galal, Fatma H

    2010-03-11

    Rift Valley fever (RVF) is an acute febrile arthropod-borne viral disease of man and animals caused by a member of the Phlebovirus genus, one of the five genera in the family Bunyaviridae. RVF virus (RVFV) is transmitted between animals and human by mosquitoes, particularly those belonging to the Culex, Anopheles and Aedes genera. Experiments were designed during RVF outbreak, 2007 in Sudan to provide an answer about many raised questions about the estimated role of vector in RVFV epidemiology. During this study, adult and immature mosquito species were collected from Khartoum and White Nile states, identified and species abundance was calculated. All samples were frozen individually for further virus detection. Total RNA was extracted from individual insects and RVF virus was detected from Culex, Anopheles and Aedes species using RT-PCR. In addition, data were collected about human cases up to November 24th, 2007 to asses the situation of the disease in affected states. Furthermore, a historical background of the RVF outbreaks was discussed in relation to global climatic anomalies and incriminated vector species. A total of 978 mosquitoes, belonging to 3 genera and 7 species, were collected during Sudan outbreak, 2007. Anopheles gambiae arabiensis was the most frequent species (80.7%) in White Nile state. Meanwhile, Cx. pipiens complex was the most abundant species (91.2%) in Khartoum state. RT-PCR was used and successfully amplified 551 bp within the M segment of the tripartite negative-sense single stranded RNA genome of RVFV. The virus was detected in female, male and larval stages of Culex and Anopheles species. The most affected human age interval was 15-29 years old followed by > or = 45 years old, 30-44 years old, and then 5-14 years old. Regarding to the profession, housewives followed by farmers, students, shepherd, workers and the free were more vulnerable to the infection. Furthermore, connection between human and entomological studies results in

  18. Blood-feeding patterns of Culex quinquefasciatus and other culicines and implications for disease transmission in Mwea rice scheme, Kenya.

    Science.gov (United States)

    Muturi, Ephantus J; Muriu, Simon; Shililu, Josephat; Mwangangi, Joseph M; Jacob, Benjamin G; Mbogo, Charles; Githure, John; Novak, Robert J

    2008-05-01

    Studies were conducted in Mwea Rice Scheme, Kenya during the period April 2005 and January 2007 to determine the host-feeding pattern of culicine mosquitoes. Mosquitoes were collected indoors and outdoors and tested for human, bovine, goat, and donkey blood meals by an Enzyme-Linked Immunosorbent Assay. A total of 1,714 blood-engorged samples comprising Culex quinquefasciatus Say (96.1%), Culex annulioris Theobald (1.8%), Culex poicilipes Theobald (0.9%), Aedes cuminsi Theobald (1.0%), Aedes taylori Edwards (0.1%), and Mansonia africana Theobald (0.1%) were tested. Except for A. taylori, in which the single blood meal tested was of bovine origin, the other species fed mostly on both bovine (range 73.3-100%) and goats (range 50-100%). Donkeys were also common hosts for all species (range 19.4-23.5%) except A. taylori and M. africana. C. quinquefasciatus was the only species containing human blood meals (0.04), and indoor collected populations of this species had significantly higher frequency of human blood meals (9.8%) compared with outdoor-collected populations (3.0%). Mixed blood feeding was dominant among culicine species comprising 50.0%, 73.3%, 73.5%, 80.6%, and 94.1% of the samples for M. africana, C. poicilipes, C. quinquefasciatus, C. annulioris, and A. cuminsi, respectively. Ten mixed blood meal combinations including a mixture of all the four hosts were observed in C. quinquefasciatus, compared to one blood meal combination for M. Africana, and two combinations for C. poicilipes, C. annulioris, and A. cuminsi. Mixed bovine and goat blood meal was the most common combination among the five culicine species followed by a mixture of donkey, bovine, and goat blood meals. We conclude that culicine species in Mwea are least likely to be vectors of lymphatic filariasis due to their high "preference" for livestock over human hosts, but they present an increased risk for arbovirus transmission particularly Rift Valley Fever virus, in which domestic animals serve

  19. Local impact of temperature and precipitation on West Nile virus infection in Culex species mosquitoes in northeast Illinois, USA

    Directory of Open Access Journals (Sweden)

    Haramis Linn

    2010-03-01

    Full Text Available Abstract Background Models of the effects of environmental factors on West Nile virus disease risk have yielded conflicting outcomes. The role of precipitation has been especially difficult to discern from existing studies, due in part to habitat and behavior characteristics of specific vector species and because of differences in the temporal and spatial scales of the published studies. We used spatial and statistical modeling techniques to analyze and forecast fine scale spatial (2000 m grid and temporal (weekly patterns of West Nile virus mosquito infection relative to changing weather conditions in the urban landscape of the greater Chicago, Illinois, region for the years from 2004 to 2008. Results Increased air temperature was the strongest temporal predictor of increased infection in Culex pipiens and Culex restuans mosquitoes, with cumulative high temperature differences being a key factor distinguishing years with higher mosquito infection and higher human illness rates from those with lower rates. Drier conditions in the spring followed by wetter conditions just prior to an increase in infection were factors in some but not all years. Overall, 80% of the weekly variation in mosquito infection was explained by prior weather conditions. Spatially, lower precipitation was the most important variable predicting stronger mosquito infection; precipitation and temperature alone could explain the pattern of spatial variability better than could other environmental variables (79% explained in the best model. Variables related to impervious surfaces and elevation differences were of modest importance in the spatial model. Conclusion Finely grained temporal and spatial patterns of precipitation and air temperature have a consistent and significant impact on the timing and location of increased mosquito infection in the northeastern Illinois study area. The use of local weather data at multiple monitoring locations and the integration of mosquito

  20. Larvicidal activity of Morinda citrifolia L. (Noni) (Family: Rubiaceae) leaf extract against Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti.

    Science.gov (United States)

    Kovendan, Kalimuthu; Murugan, Kadarkarai; Shanthakumar, Shanmugam Perumal; Vincent, Savariar; Hwang, Jiang-Shiou

    2012-10-01

    Morinda citrifolia leaf extract was tested for larvicidal activity against three medically important mosquito vectors such as malarial vector Anopheles stephensi, dengue vector Aedes aegypti, and filarial vector Culex quinquefasciatus. The plant material was shade dried at room temperature and powdered coarsely. From the leaf, 1-kg powder was macerated with 3.0 L of hexane, chloroform, acetone, methanol, and water sequentially for a period of 72 h each and filtered. The yield of extracts was hexane (13.56 g), chloroform (15.21 g), acetone (12.85 g), methanol (14.76 g), and water (12.92 g), respectively. The extracts were concentrated at reduced temperature on a rotary vacuum evaporator and stored at a temperature of 4°C. The M. citrifolia leaf extract at 200, 300, 400, 500, and 600 ppm caused a significant mortality of three mosquito species. Hexane, chloroform, acetone, and water caused moderate considerable mortality; however, the highest larval mortality was methanolic extract, observed in three mosquito vectors. The larval mortality was observed after 24-h exposure. No mortality was observed in the control. The third larvae of Anopheles stephensi had values of LC(50) = 345.10, 324.26, 299.97, 261.96, and 284.59 ppm and LC(90) = 653.00, 626.58, 571.89, 505.06, and 549.51 ppm, respectively. The Aedes aegypti had values of LC(50) = 361.75, 343.22, 315.40, 277.92, and 306.98 ppm and LC(90) = 687.39, 659.02, 611.35, 568.18, and 613.25 ppm, respectively. The Culex quinquefasciatus had values of LC(50) = 382.96, 369.85, 344.34, 330.42, and 324.64 ppm and LC(90) = 726.18, 706.57, 669.28, 619.63, and 644.47 ppm, respectively. The results of the leaf extract of M. citrifolia are promising as good larvicidal activity against the mosquito vector Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. This is a new eco-friendly approach for the control of vector control programs. Therefore, this study provides first report on the larvicidal activities against three

  1. 竹提取物对淡色库蚊Culex pipiens pallens幼虫的活性评价%EVALUATION OF EXTRACTS FROM BAMBOO FOR BIOLOGICAL ACTIVITY AGAINST CULEX PIPIENS PALLENS

    Institute of Scientific and Technical Information of China (English)

    操海群; 岳永德; 彭镇华; 花日茂; 汤锋

    2004-01-01

    报道了竹提取物对淡色库蚊Culex pipiens pallens幼虫的毒杀作用.研究结果表明,巨县苦竹(Pleioblastusjuxianensis)、白纹短穗竹(Brachystachyum albostriatum)、灰水竹(Phyllostachysplatyglossa)和苦竹(Pleioblastus amarus)提取物对淡色库蚊幼虫的24h致死中浓度(LC50)分别为30.65 mg/L、53.94 mg/L、41.21 mg/L、54.49 mg/L.巨县苦竹索氏抽提物对淡色库蚊幼虫的毒杀作用明显强于间歇振荡提取物,前者对淡色库蚊幼虫的LC50为30.65 mg/L,95%置信限27.12~34.63 mg/L;后者的LC50为48.34 mg/L,95%置信限为40.37~59.62 mg/L.巨县苦竹乙醚浸提物对淡色库蚊幼虫的毒杀作用效果显著,125mg/L浓度时12h校正死亡率为56.67%,24h后达92.90%;石油醚浸提物及甲醇浸提物对淡色库蚊幼虫的毒杀作用则不明显,24h校正死亡率均不超过40%.研究结果将有助于综合利用竹类资源,开发新型环境友好农药.%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 30.65 mg/L,53.94 mg/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

  2. Insecticidal, repellent and oviposition-deterrent activity of selected essential oils against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus.

    Science.gov (United States)

    Prajapati, Veena; Tripathi, A K; Aggarwal, K K; Khanuja, S P S

    2005-11-01

    Essential oils extracted from 10 medicinal plants were evaluated for larvicidal, adulticidal, ovicidal, oviposition-deterrent and repellent activities towards three mosquito species; Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. The essential oils of Juniperus macropoda and Pimpinella anisum were highly effective as both larvicidal and ovicidal. The essential oil of P. anisum showed toxicity against 4th instar larvae of A. stephensi and A. aegypti with equivalent LD95 values of 115.7 microg/ml, whereas it was 149.7 microg/ml against C. quinquefasciatus larvae. Essential oils of Zingiber officinale and Rosmarinus officinalis were found to be ovicidal and repellent, respectively towards the three mosquito species. The essential oil of Cinnamomum zeylanicum resulted into highest repellent (RD95) values of 49.6, 53.9 and 44.2 mg/mat against A. stephensi, A. aegypti and C. quinquefasciatus, respectively apart from oviposition-deterrent potential.

  3. A laboratory study of cyromazine on Aedes aegypti and Culex quinquefasciatus and its activity on selected predators of mosquito larvae.

    Science.gov (United States)

    Nelson, F R; Holloway, D; Mohamed, A K

    1986-09-01

    In a laboratory study, the insect growth regulator, cyromazine, exerted a high level of biological activity on Aedes aegypti and Culex quinquefasciatus treated in the 4th larval instar. At 1.5 and 1.0 ppm this IGR produced 97 and 99% inhibition of emergence in adult Ae. aegypti, respectively. In Cx. quinquefasciatus, there was 99% inhibition at 1 ppm and complete inhibition at 1.5 ppm. The overall pupal mortality was higher than larval or adult stages of both species. This material induced different types of morphogenetic abnormalities in pupae and adults of the 2 species similar to those induced by other IGRs. However, most abnormalities were observed in the pupal stage. Adverse effects were not detected on the 4 mosquito predator species during the acute or posttreatment tests.

  4. First Record of Culex Coronator in Virginia, with Notes on Its Rapid Dispersal, Trapping Methods, and Biology.

    Science.gov (United States)

    Akaratovic, Karen I; Kiser, Jay P

    2017-09-01

    Culex coronator is a Neotropical mosquito species that was first described in Trinidad in the early 20th century. Since then, the species has been discovered from Patagonia to the southern USA. A single adult female Cx. coronator was collected on November 1, 2016, in Suffolk, VA, in a BG-Sentinel 2® trap during routine mosquito surveillance. This represents the 1st record of this species in the state of Virginia and the northernmost record in the USA. Based on male specimens examined from Texas and Mississippi, Cx. coronator sensu stricto seems to be the only species from the complex expanding into the southeastern USA. A comprehensive review of the available literature from the southern and southeastern USA is provided describing trapping methods, ecological, and biological information.

  5. Larvicidal, adulticidal, repellency and smoke toxic efficacy of Ficus krishnae against Anopheles stephensi Liston and Culex vishnui group mosquitoes

    Directory of Open Access Journals (Sweden)

    Koyel Mallick Haldar

    2014-02-01

    Full Text Available Objective: To establish the plant Ficus krishnae as potential antimosquito agent. Methods: Larvicidal and adulticidal efficacy of ethyl acetate and methanol extracts of leaves of Ficus krishnae were evaluated against 3rd instar larvae and adults of Anopheles stephensi and Culex vishnui group mosquito for 24 h. Smoke toxicity test along with test for repellency on adult forms of the two mosquitoes were performed by the methanol extract. Results: The mortality rate varies in a dose dependent characteristic. The tests for larvicidal and adulticidal activity with both the solvent extracts showed significant efficiencies against the mosquitoes studied. The outcome of smoke toxicity test and repellency test were impressive. Conclusion: The study reveals that the solvent extracts of Ficus krishnae could be an effective natural alternative to get control over the mosquito population.

  6. Morphological studies of the mimeticus group of Genus Culex (Diptera : Culicidae) : I. Pale spots on wing and wing venation

    National Research Council Canada - National Science Library

    松尾, 喜久男; 連, 日清; 久納, 巌; 伊藤, 寿美代

    1974-01-01

    ハマダライエカ群成虫の翅の斑紋は, 種により特異的であり, また観察が簡単なため本群成虫の同定にはもっぱらこの斑紋が利用されるが, この形質の個体変異については明らかではない。そこで本群の蚊種のうち日本産Culex orientalis, C. mimeticusおよび台湾産C. neomimulus 3種の斑紋に...

  7. Mtx toxins from Lysinibacillus sphaericus enhance mosquitocidal cry-toxin activity and suppress cry-resistance in Culex quinquefasciatus.

    Science.gov (United States)

    Wirth, Margaret C; Berry, Colin; Walton, William E; Federici, Brian A

    2014-01-01

    The interaction of Mtx toxins from Lysinibacillus sphaericus (formerly Bacillus sphaericus) with Bacillus thuringiensis subsp. israelensis Cry toxins and the influence of such interactions on Cry-resistance were evaluated in susceptible and Cry-resistant Culex quinquefasciatus larvae. Mtx-1 and Mtx-2 were observed to be active against both susceptible and resistant mosquitoes; however varying levels of cross-resistance toward Mtx toxins were observed in the resistant mosquitoes. A 1:1 mixture of either Mtx-1 or Mtx-2 with different Cry toxins generally showed moderate synergism, but some combinations were highly toxic to resistant larvae and suppressed resistance. Toxin synergy has been demonstrated to be a powerful tool for enhancing activity and managing Cry-resistance in mosquitoes, thus Mtx toxins may be useful as components of engineered bacterial larvicides. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Efficacy of herbal essential oils as insecticide against Aedes aegypti (Linn.), Culex quinquefasciatus (Say) and Anopheles dirus (Peyton and Harrison).

    Science.gov (United States)

    Phasomkusolsil, Siriporn; Soonwera, Mayura

    2011-09-01

    The essential oils of Cananga odorata (ylang ylang), Citrus sinensis (orange), Cymbopogon citratus (lemongrass), Cymbopogon nardus (citronella grass), Eucalyptus citriodora (eucalyptus), Ocimum basilicum (sweet basil) and Syzygium aromaticum (clove), were tested for their insecticide activity against Aedes aegypti, Culex quinquefasciatus and Anopheles dirus using the WHO standard susceptibility test. These were applied in soybean oil at dose of 1%, 5% and 10% (w/v). C. citratus had the KT, values against the three mosquito species tested but the knockdown rates (at 10, 30 and 60 minutes) were lower than some essential oils. C. citratus oil had high insecticidal activity against Ae. aegypti, Cx. quinquefasciatus and An. dirus, with LC50 values of < 0.1, 2.22 and < 0.1%, respectively. Ten percent C. citratus gave the highest mortality rates (100%) 24 hours after application. This study demonstrates the potential for the essential oil of C. citratus to be used as an insecticide against 3 species of mosquitoes.

  9. Development of a Bacillus sphaericus tablet formulation and its evaluation as a larvicide in the biological control of Culex quinquefasciatus

    Directory of Open Access Journals (Sweden)

    Flávia P Morais de Medeiros

    2005-07-01

    Full Text Available This study aimed to analyze the final fermentation culture of Bacillus sphaericus 2362, standardize it and develop an active tablet formulation for use in urban mosquito breeding sites. It was performed in three phases: analysis and standardization of a B. sphaericus fermented culture; physical, chemical, and biological analysis of the active powder (solubility, residual humidity, particle size, resting angle, flowing off time, compacted density, and biological activity against Culex quinquefasciatus larvae; and the development of fast-disintegrating tablets. Five formulations with differing compositions were developed and a UV protector was added to the selected formulation. The formulation products with or without UV protector, as well as the active powder caused 100% larval mortality from 1 day to 2 months after a single treatment under simulated field conditions. These results show that the UV protector does not affect the initial larvicide activity of B. sphaericus, nor its persistence over a period of two months.

  10. Development of a Bacillus sphaericus tablet formulation and its evaluation as a larvicide in the biological control of Culex quinquefasciatus.

    Science.gov (United States)

    Medeiros, Flávia P Morais de; Santos, Maria Alice Varjal de Melo; Regis, Leda; Rios, Eugênia M Maranhão; Rolim Neto, Pedro J

    2005-07-01

    This study aimed to analyze the final fermentation culture of Bacillus sphaericus 2362, standardize it and develop an active tablet formulation for use in urban mosquito breeding sites. It was performed in three phases: analysis and standardization of a B. sphaericus fermented culture; physical, chemical, and biological analysis of the active powder (solubility, residual humidity, particle size, resting angle, flowing off time, compacted density, and biological activity against Culex quinquefasciatus larvae); and the development of fast-disintegrating tablets. Five formulations with differing compositions were developed and a UV protector was added to the selected formulation. The formulation products with or without UV protector, as well as the active powder caused 100% larval mortality from 1 day to 2 months after a single treatment under simulated field conditions. These results show that the UV protector does not affect the initial larvicide activity of B. sphaericus, nor its persistence over a period of two months.

  11. Efficacy of indigenous larvivorous fishes against Culex quinquefasciatus in the presence of alternative prey: implications for biological control.

    Science.gov (United States)

    Aditya, Gautam; Pal, Santanu; Saha, Nabaneeta; Saha, Goutam

    2012-12-01

    Indigenous larvivorous fishes bear potential for regulating vector mosquitoes through trophic interactions. The mosquito prey preference of five indigenous larvivorous fishes in the presence of alternative food items was assessed to highlight their use in mosquito vector management. Laboratory experiments were carried out using the larvivorous fishes Ambassis (=Chanda) nama, Parambassis (=Chanda) ranga, Colisa fasciatus, Esomus danricus and Aplocheilus panchax, as predators and IV instar Culex quinquefasciatus larvae as target prey. Mosquito prey preference of these fishes in the presence of chironomid larvae, tubificid worms and artificial fish foods, in varied proportions, were assessed using preference index. The fishes consumed considerable amount of mosquito larvae both in absence and presence of alternative food items. However, the positive selectivity for mosquito larvae at all densities were significantly (p control by these fishes.

  12. Insecticidal activity of isobutylamides derived from Piper nigrum against adult of two mosquito species, Culex pipiens pallens and Aedes aegypti.

    Science.gov (United States)

    Park, Il-Kwon

    2012-01-01

    The insecticidal activity of Piper nigrum fruit-derived piperidine alkaloid (piperine) and N-isobutylamide alkaloids (pellitorine, guineensine, pipercide and retrofractamide A) against female adults of Culex pipiens pallens and Aedes aegypti was examined. On the basis of 24-h LD(50) values, the compound most toxic to female C. pipiens pallens was pellitorine (0.4 µg/♀) followed by guineensine (1.9 µg/♀), retrofractamide A (2.4 µg/♀) and pipercide (3.2 µg/♀). LD(50) value of chlorpyrifos was 0.03 µg/♀. Against female A. aegypti, the insecticidal activity was more pronounced in pellitorine (0.17 µg/♀) than in retrofractamide A (1.5 µg/♀), guineensine (1.7 µg/♀), and pipercide (2.0 µg/♀). LD(50) value of chlorpyrifos was 0.0014 µg/♀.

  13. Secreted Vago restricts West Nile virus infection in Culex mosquito cells by activating the Jak-STAT pathway.

    Science.gov (United States)

    Paradkar, Prasad N; Trinidad, Lee; Voysey, Rhonda; Duchemin, Jean-Bernard; Walker, Peter J

    2012-11-13

    Although West Nile virus (WNV) and other arthropod-borne viruses are a major public health problem, the mechanisms of antiviral immunity in mosquitoes are poorly understood. Dicer-2, responsible for the RNAi-mediated response through the C-terminal RNase-III domain, also contains an N-terminal DExD/H-box helicase domain similar to mammalian RIG-I/MDA5 which, in Drosophila, was found to be required for activation of an antiviral gene, Vago. Here we show that the Culex orthologue of Vago (CxVago) is up-regulated in response to WNV infection in a Dicer-2-dependent manner. Further, our data show that CxVago is a secreted peptide that restricts WNV infection by activation of the Jak-STAT pathway. Thus, Vago appears to function as an IFN-like antiviral cytokine in mosquitoes.

  14. Larvivorous activity of Poecilia reticulata against Culex quinquefasciatus larvae in a polluted water drain in Hardwar, India.

    Science.gov (United States)

    Dua, Virendra K; Pandey, A C; Rai, Swapnil; Dash, A P

    2007-12-01

    The efficacy of the larvivorous fish Poecilia reticulata against mosquito larvae was monitored in a drain at Bharat Heavy Electricals Limited, Hardwar, India. The water was polluted and the water flow was in some way impeded. Poecilia reticulata failed to feed on Culex quinquefasciatus larvae in this drain. Laboratory experiments also confirmed the inefficacy of P. reticulata as a predator of Cx. quinquefasciatus larvae during the first 24 h. Significant differences in the efficacy of P. reticulata against Cx. quinquefasciatus were recorded between polluted water and drinking water. Poecilia reticulata preferred to feed on other available food present in the polluted water rather than on Cx. quinquefasciatus larvae. This was verified by the identification of plankton in the gut content of the fish and by the high density of plankton present in the polluted water.

  15. Sampling Design Influences the Observed Dominance of Culex tritaeniorhynchus: Considerations for Future Studies of Japanese Encephalitis Virus Transmission.

    Science.gov (United States)

    Lord, Jennifer S; Al-Amin, Hasan Mohammad; Chakma, Sumit; Alam, Mohammad Shafiul; Gurley, Emily S; Pulliam, Juliet R C

    2016-01-01

    Mosquito sampling during Japanese encephalitis virus (JEV)-associated studies, particularly in India, has usually been conducted via aspirators or light traps to catch mosquitoes around cattle, which are dead-end hosts for JEV. High numbers of Culex tritaeniorhynchus, relative to other species, have often been caught during these studies. Less frequently, studies have involved sampling outdoor resting mosquitoes. We aimed to compare the relative abundance of mosquito species between these two previously used mosquito sampling methods. From September to December 2013 entomological surveys were undertaken in eight villages in a Japanese encephalitis (JE) endemic area of Bangladesh. Light traps were used to collect active mosquitoes in households, and resting boxes and a Bina Pani Das hop cage were used near oviposition sites to collect resting mosquitoes. Numbers of humans and domestic animals present in households where light traps were set were recorded. In five villages Cx. tritaeniorhynchus was more likely to be selected from light trap samples near hosts than resting collection samples near oviposition sites, according to log odds ratio tests. The opposite was true for Cx. pseudovishnui and Armigeres subalbatus, which can also transmit JEV. Culex tritaeniorhynchus constituted 59% of the mosquitoes sampled from households with cattle, 28% from households without cattle and 17% in resting collections. In contrast Cx. pseudovishnui constituted 5.4% of the sample from households with cattle, 16% from households with no cattle and 27% from resting collections, while Ar. subalbatus constituted 0.15%, 0.38%, and 8.4% of these samples respectively. These observations may be due to differences in timing of biting activity, host preference and host-seeking strategy rather than differences in population density. We suggest that future studies aiming to implicate vector species in transmission of JEV should consider focusing catches around hosts able to transmit JEV.

  16. Infection of malaria (Anopheles gambiae s.s.) and filariasis (Culex quinquefasciatus) vectors with the entomopathogenic fungus Metarhizium anisopliae.

    Science.gov (United States)

    Scholte, Ernst-Jan; Njiru, Basilio N; Smallegange, Renate C; Takken, Willem; Knols, Bart G J

    2003-09-15

    Current intra-domiciliary vector control depends on the application of residual insecticides and/or repellents. Although biological control agents have been developed against aquatic mosquito stages, none are available for adults. Following successful use of an entomopathogenic fungus against tsetse flies (Diptera: Glossinidae) we investigated the potency of this fungus as a biological control agent for adult malaria and filariasis vector mosquitoes. In the laboratory, both sexes of Anopheles gambiae sensu stricto and Culex quinquefasciatus were passively contaminated with dry conidia of Metarhizium anisopliae. Pathogenicity of this fungus for An. gambiae was further tested for varying exposure times and different doses of oil-formulated conidia. Comparison of Gompertz survival curves and LT50 values for treated and untreated specimens showed that, for both species, infected mosquitoes died significantly earlier (p control groups. No differences in LT50 values were found for different exposure times (24, 48 hrs or continuous exposure) of An. gambiae to dry conidia. Exposure to oil-formulated conidia (doses ranging from 1.6 x 10(7) to 1.6 x 10(10) conidia/m2) gave LT50 values of 9.69 +/- 1.24 (lowest dose) to 5.89 +/- 0.35 days (highest dose), with infection percentages ranging from 4.4-83.7%. Our study marks the first to use an entomopathogenic fungus against adult Afrotropical disease vectors. Given its high pathogenicity for both adult Anopheles and Culex mosquitoes we recommend development of novel targeted indoor application methods for the control of endophagic host-seeking females.

  17. Infection of malaria (Anopheles gambiae s.s. and filariasis (Culex quinquefasciatus vectors with the entomopathogenic fungus Metarhizium anisopliae

    Directory of Open Access Journals (Sweden)

    Smallegange Renate C

    2003-09-01

    Full Text Available Abstract Background Current intra-domiciliary vector control depends on the application of residual insecticides and/or repellents. Although biological control agents have been developed against aquatic mosquito stages, none are available for adults. Following successful use of an entomopathogenic fungus against tsetse flies (Diptera: Glossinidae we investigated the potency of this fungus as a biological control agent for adult malaria and filariasis vector mosquitoes. Methods In the laboratory, both sexes of Anopheles gambiae sensu stricto and Culex quinquefasciatus were passively contaminated with dry conidia of Metarhizium anisopliae. Pathogenicity of this fungus for An. gambiae was further tested for varying exposure times and different doses of oil-formulated conidia. Results Comparison of Gompertz survival curves and LT50 values for treated and untreated specimens showed that, for both species, infected mosquitoes died significantly earlier (p 50 values were found for different exposure times (24, 48 hrs or continuous exposure of An. gambiae to dry conidia. Exposure to oil-formulated conidia (doses ranging from 1.6 × 107 to 1.6 × 1010 conidia/m2 gave LT50 values of 9.69 ± 1.24 (lowest dose to 5.89 ± 0.35 days (highest dose, with infection percentages ranging from 4.4–83.7%. Conclusion Our study marks the first to use an entomopathogenic fungus against adult Afrotropical disease vectors. Given its high pathogenicity for both adult Anopheles and Culex mosquitoes we recommend development of novel targeted indoor application methods for the control of endophagic host-seeking females.

  18. Emergence of resistance and resistance management in field populations of tropical Culex quinquefasciatus to the microbial control agent Bacillus sphaericus.

    Science.gov (United States)

    Mulla, Mir S; Thavara, Usavadee; Tawatsin, Apiwat; Chomposri, Jakkrawarn; Su, Tianyun

    2003-03-01

    In recent years, highly potent mosquitocidal strains of the microbial agent Bacillus sphaericus (Bsph) have been isolated and developed for the control of mosquito larvae around the world. Laboratory selection experiments with the most active strains and their use in large-scale operational mosquito control programs resulted in the emergence of resistance in larvae of the Culex pipiens complex. This generated great concern among vector control agencies around the world, who feared reduced efficacy of this highly active larvicidal agent. To address this issue, the current studies were started to find practical strategies for controlling resistant mosquitoes and more importantly to develop resistance management strategies that would prevent or delay development of resistance. We initiated field studies in 3 low-income communities in Nonthaburi Province, Thailand. In 1 of the communities, larvae of Culex quinquefasciatus that were highly resistant (>125,000-fold) to Bsph strain 2362 were successfully controlled with applications of Bacillus thuringiensis var. israelensis (Bti) alone or in combination with Bsph. To prevent or delay resistance to Bsph, 2 other sites were selected, 1 treated with Bsph 2362 alone and the other treated with a mixture of Bsph 2362 and Bti. Mosquitoes treated with Bsph 2362 alone showed some resistance by the 9th treatment and almost complete failure of control occurred by the 17th treatment. After 9 treatments with the mixture over a 9-month period at another site, no noticeable change in susceptibility to Bsph was detected. During this period, the site treated with Bsph alone required 19 treatments, whereas the site treated with mixtures took only 9 treatments because of slower resurgence of larvae at the site treated with the mixture than at the site treated with Bsph alone. This is the 1st field evidence for delay or prevention of resistance to microbial agents in larval Cx. quinquefasciatus by using mixtures of Bti and Bsph. Further

  19. Field detection of Tembusu virus in western Thailand by rt-PCR and vector competence determination of select culex mosquitoes for transmission of the virus.

    Science.gov (United States)

    O'Guinn, Monica L; Turell, Michael J; Kengluecha, Ampornpan; Jaichapor, Boonsong; Kankaew, Prasan; Miller, R Scott; Endy, Timothy P; Jones, James W; Coleman, Russell E; Lee, John S

    2013-11-01

    Tembusu virus (TMUV; Ntaya serocomplex) was detected in two pools of mosquitoes captured near Sangkhlaburi, Thailand, as well as from sera from sentinel ducks from the same area. Although TMUV has been isolated from several mosquito species in Asia, no studies have ever shown competent vectors for this virus. Therefore, we allowed mosquitoes captured near Sangkhlaburi to feed on young chickens that had been infected with TMUV. These mosquitoes were tested approximately 2 weeks later to determine infection, dissemination, and transmission rates. Culex vishnui developed high viral titers after feeding on TMUV-infected chicks and readily transmitted virus to naïve chickens. In contrast, Cx. fuscocephala seemed less susceptible to infection, and more importantly, zero of five fuscocephala with a disseminated infection transmitted virus by bite, indicating a salivary gland barrier. These results provide evidence for the involvement of Culex mosquitoes in the transmission of TMUV in the environment.

  20. Temperature and water quality effects in simulated woodland pools on the infection of Culex mosquito larvae by Lagenidium giganteum (Oomycetes: Lagenidiales) in North Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, D.R.; Axtell, R.C.

    1987-06-01

    Asexual stages of the California (CA) isolate of Lagenidium giganteum cultured on sunflower seed extract (SFE)-agar, were applied to outdoor pools containing Culex larvae near Raleigh, NC in August and September 1984. Infection rates among the larvae ranged from 19 to 74% at 2-4 days posttreatment and subsequent epizootics eliminated most of the newly hatched larvae for at least 10 days posttreatment. Substantial reductions in numbers of larvae and adult emergence were achieved from a single application of the fungus. Water quality and temperature data are presented. From laboratory assays of organically polluted water, the percent infection of Culex quinquefasciatus by the fungus was correlated with water quality and temperature. A logistic model of water quality (COD and NH/sub 3/-N) effects on infectivity rates by the CA isolate is described.

  1. PENGARUH VARIASI DOSIS LARUTAN BUAH BELIMBING WULUH (Averrhoa bilimbi L.TERHADAP MORTALITAS LARVA NYAMUK Culex sp. SEBAGAI SUMBER BELAJAR BIOLOGI PADA MATERI INSEKTA

    Directory of Open Access Journals (Sweden)

    Bagas Rasid Sidik

    2015-11-01

    Full Text Available Control of larvae of Culex sp. can be done with larvicides. Larvicides used in an attempt to reduce the population of larvae in a breeding place or for termination of the chain of mosquito breeding. Insect repellent effective to kill mosquitoes, but that has not been come mosquito larvae will develop into mosquitoes. Insect repellent made from synthetic chemicals if used excessively will cause adverse effects to humans such as respiratory disorders, digestive, and the environment. The purpose of this study was to determine (1 Whether or not the effect of giving a solution of fruit starfruit (Averrhoa bilimbi, L. against Culex sp. mosquito larvae mortality, (2 determine the most appropriate dosage on mortality of larvae of mosquito Culex sp., (3 Compile the results of the research as a high school biology class X LKPS semester two. This study uses the method of experiment, the draft design used was completely randomized design Variety (CRD with the control (P0 and 4 treatments, namely P1: a dose of1/99 ml, P2: dose2/98 ml, P3: dose3/97 ml, and P4: a dose4/96 ml with 6 replicates each, the number of larvae 150 animals. Larva l sampling and testing conducted at Flores Street No. 19 Ganjar Supreme 14/2 City Metro. The test was analyzed using one-way Anava non-parametric Kruskall-Wallis test. The results of the analysis are obtained as follows: (1 There is a very significant influence on the administration of a solution of fruit starfruit (Averrhoa bilimbi, L. against Culex mosquito larvae mortality due to the α sp 0.05,   at α 0.01 in Chi-square table, (2 the mortality of larvae of Culex for 24 consecutive hour sare from lowest to highest mortality percentage is P0=0%, P1=60%, P2=83.33%, 83.33% =P3, andP4=86,66%. Based on the results of research and discussion we concluded that: (1 There is the effect of star fruit solution on mortality of larvae of Culex sp mosquitoes, with coefficientH=17.73>Chi-square value of7.81at α level of 0.05, 11, 3

  2. Ecological Niche Modeling of Potential West Nile Virus Vector Mosquito Species in Iowa

    OpenAIRE

    2010-01-01

    Ecological niche modeling (ENM) algorithms, Maximum Entropy Species Distribution Modeling (Maxent) and Genetic Algorithm for Rule-set Prediction (GARP), were used to develop models in Iowa for three species of mosquito — two significant, extant West Nile virus (WNV) vectors (Culex pipiens L and Culex tarsalis Coquillett (Diptera: Culicidae)), and the nuisance mosquito, Aedes vexans Meigen (Diptera: Culicidae), a potential WNV bridge vector. Occurrence data for the three mosquito species from ...

  3. Efficacy of three formulations of diflubenzuron, an insect growth regulator, against Culex quinquefasciatus Say, the vector of Bancroftian filariasis in India

    OpenAIRE

    C Sadanandane; Doss, P. S. Boopathi; Jambulingam, P.

    2012-01-01

    Background & objectives: Insect growth regulators (IGRs) offer alternatives to conventional chemical larvicides that pose problem of resistance and environmental safety. However, only a limited number of IGRs have been approved for use in mosquito control. In the present study, two new formulations of the IGR diflubenzuron, 2 per cent granular (GR) and 2 per cent tablet (DT) were tested for its efficacy against Culex quinquefasciatus, in comparison to its 25 per cent wettable powder (WP) form...

  4. The Mosquitoes of the Subgenus Culex in Southwestern Asia and Egypt (Diptera: Culicidae) (Contributions of the American Entomological Institute. Volume 24, Number 1, 1988)

    Science.gov (United States)

    1988-01-01

    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

  5. Larvicidal, Ovicidal, and Repellent Activities of Marine Sponge Cliona celata (Grant) Extracts against Culex quinquefasciatus Say and Aedes aegypti L. (Diptera: Culicidae)

    OpenAIRE

    Reegan, Appadurai Daniel; Kinsalin, Arokia Valan; Paulraj, Michael Gabriel; Ignacimuthu,Savarimuthu

    2013-01-01

    Solvent extracts of marine sponge Cliona celata (Grant) were screened for larvicidal, ovicidal, and repellent properties against the filarial vector Culex quinquefasciatus Say and dengue vector Aedes aegypti L. Larvicidal and ovicidal activities of hexane, ethyl acetate, and methanol extracts were tested in four different concentrations ranging as 62.5, 125, 250, and 500 ppm. Among the three solvent extracts of C. celata, methanol extract showed the highest larvicidal activity at 500 ppm agai...

  6. Differential effect of human ivermectin treatment on blood feeding Anopheles gambiae and Culex quinquefasciatus

    OpenAIRE

    Derua, Yahya A; Kisinza, William N; Simonsen, Paul Erik

    2015-01-01

    BACKGROUND: Widespread and large scale use of ivermectin in humans and domestic animals can have unexpected effects on non-target organisms. As a search for a possible explanation for an observed longitudinal decline in density of anopheline vector mosquitoes, but not in Culex quinquefasciatus, in an area of north-eastern Tanzania which has been exposed to ivermectin mass drug administration, this study assessed and compared the effect of human ivermectin treatment on blood feeding Anopheles ...

  7. Medical Entomology Studies - III. A Revision of the Subgenus Culex in the Oriental Region (Diptera: Culicidae) (Contributions of the American Entomological Institute. Volume 12, Number 2)

    Science.gov (United States)

    1976-01-01

    Subgroup with quinquefasciatus which is widespread throughout tropical parts of the world, (2) TrifiZatus Subgroup with vegans and hutchinsoni, both...region; torrentium Martini 1925 from the western Palearctic; vegans Wiedemann 1828 from the eastern Pale- arctic; pervigiluns Bergroth 1889, pacificus...discovered when the fauna is thoroughly examined. 2. C ULEX (C ULEX) VAGANS WIEDEMANN (Figs. 4, 5, 14) Culex vegans Wiedemann 1828: 545 (d, 0

  8. Oviposition deterrent activity from the ethanolic extract of Pongamia pinnata, Coleus forskohlii, and Datura stramonium leaves against Aedes aegypti and Culex quinquefaciatus

    OpenAIRE

    Swathi, S.; Murugananthan, G.; Ghosh, S. K.

    2010-01-01

    Mosquitoes are responsible for spread of many diseases than any other group of arthropods. Diseases such as malaria, filariasis, dengue hemorrhagic fever (DHF), and chikunguinya are real threat to mankind. In the present study, ethanolic extracts of leaves of Pongamia pinnata, Coleus forskohlii, and Datura stramonium were evaluated for oviposition deterrent activity against Aedes aegypti and Culex quinquefasciatus. The oviposition deterrent tests of ethanolic extract of Pongamia pinnata, Cole...

  9. Larvivorous Potential of Different Stages of Culex tigripes (Diptera, Culicidae) in the Prospective of its Use in Biological Control of Malaria Vectors

    OpenAIRE

    Basabose, K.

    1996-01-01

    Carried out in the laboratory, the present study tends to assess the larvivorous potential of different stages of Culex tigripes against malaria vectors. The four stages of C. tigripes have effectively a larvivorous activity and may be used in the biological control of mosquito larvae, vector of malaria. Neither lower or higher larval density, large or small size of larvae nor any position pattern of prey larvae from the water surface do inhibit the larvivorous behaviour of C. tigripes.

  10. Larvivorous Potential of Different Stages of Culex tigripes (Diptera, Culicidae in the Prospective of its Use in Biological Control of Malaria Vectors

    Directory of Open Access Journals (Sweden)

    Basabose, K.

    1996-01-01

    Full Text Available Carried out in the laboratory, the present study tends to assess the larvivorous potential of different stages of Culex tigripes against malaria vectors. The four stages of C. tigripes have effectively a larvivorous activity and may be used in the biological control of mosquito larvae, vector of malaria. Neither lower or higher larval density, large or small size of larvae nor any position pattern of prey larvae from the water surface do inhibit the larvivorous behaviour of C. tigripes.

  11. Larvicidal potentiality, longevity and fecundity inhibitory activities of Bacillus sphaericus (Bs G3-IV on vector mosquitoes, Aedes aegypti and Culex quinquefasciatus

    Directory of Open Access Journals (Sweden)

    Arjunan Nareshkumar

    2012-12-01

    Full Text Available Intervention measures to control the transmission of vector-borne diseases include control of the vector population. In mosquito control, synthetic insecticides used against both the larvae (larvicides and adults (adulticides create numerous problems, such as environmental pollution, insecticide resistance and toxic hazards to humans. In the present study, a bacterial pesticide, Bacillus sphaericus (Bs G3-IV, was used to control the dengue and filarial vectors, Aedes aegypti and Culex quinquefasciatus. Bacillus sphaericus (Bs G3-IV was very effective against Aedes aegypti and Culex quinquefasciatus, showing significant larval mortality. Evaluated lethal concentrations (LC50 and LC90 were age-dependent, with early instars requiring a lower concentration compared with later stages of mosquitoes. Culex quinquefasciatus was more susceptible to Bacillus sphaericus (Bs G3-IV than was Aedes aegypti. Fecundity rate was highly reduced after treatment with different concentrations of Bacillus sphaericus (Bs G3-IV. Larval and pupal longevity both decreased after treatment with Bacillus sphaericus (Bs G3-IV, total number of days was lower in the B. sphaericus treatments compared with the control. Our results show the bacterial pesticide Bacillus sphaericus (Bs G3-IV to be an effective mosquito control agent that can be used for more integrated pest management programs.

  12. A checklist of the 67 mosquito species of Ontario, Canada.

    Science.gov (United States)

    Giordano, Bryan V; Gasparotto, Alessio; Hunter, Fiona F

    2015-03-01

    We provide an updated checklist of 67 endemic mosquito species known from Ontario, Canada. Nine endemic species are added to the checklist found in Darsie and Ward (2005) : Aedes cantator, Ae. churchillensis, Ae. nigripes, Ae. pullatus, Anopheles perplexens, An. crucians, An. smaragdinus, Culex erraticus, and Cx. salinarius. Only 4 specimens of Ae. albopictus have been recorded in Ontario since 2001 despite concerted efforts to find this species; therefore, it is considered an "accidental" species and is excluded from the checklist.

  13. Spatially targeting Culex quinquefasciatus aquatic habitats on modified land cover for implementing an Integrated Vector Management (IVM program in three villages within the Mwea Rice Scheme, Kenya

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    Githure John

    2006-05-01

    Full Text Available Abstract Background Continuous land cover modification is an important part of spatial epidemiology because it can help identify environmental factors and Culex mosquitoes associated with arbovirus transmission and thus guide control intervention. The aim of this study was to determine whether remotely sensed data could be used to identify rice-related Culex quinquefasciatus breeding habitats in three rice-villages within the Mwea Rice Scheme, Kenya. We examined whether a land use land cover (LULC classification based on two scenes, IKONOS at 4 m and Landsat Thematic Mapper at 30 m could be used to map different land uses and rice planted at different times (cohorts, and to infer which LULC change were correlated to high density Cx. quinquefasciatus aquatic habitats. We performed a maximum likelihood unsupervised classification in Erdas Imagine V8.7® and generated three land cover classifications, rice field, fallow and built environment. Differentially corrected global positioning systems (DGPS ground coordinates of Cx. quinquefasciatus aquatic habitats were overlaid onto the LULC maps generated in ArcInfo 9.1®. Grid cells were stratified by levels of irrigation (well-irrigated and poorly-irrigated and varied according to size of the paddy. Results Total LULC change between 1988–2005 was 42.1 % in Kangichiri, 52.8 % in Kiuria and and 50.6 % Rurumi. The most frequent LULC changes was rice field to fallow and fallow to rice field. The proportion of aquatic habitats positive for Culex larvae in LULC change sites was 77.5% in Kangichiri, 72.9% in Kiuria and 73.7% in Rurumi. Poorly – irrigated grid cells displayed 63.3% of aquatic habitats among all LULC change sites. Conclusion We demonstrate that optical remote sensing can identify rice cultivation LULC sites associated with high Culex oviposition. We argue that the regions of higher Culex abundance based on oviposition surveillance sites reflect underlying differences in abundance of larval

  14. Proteolytic profiling and comparative analyses of active trypsin-like serine peptidases in preimaginal stages of Culex quinquefasciatus

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    Borges-Veloso Andre

    2012-06-01

    Full Text Available Abstract Background The mosquito Culex quinquefasciatu s, a widespread insect in tropical and sub-tropical regions of the world, is a vector of multiple arboviruses and parasites, and is considered an important risk to human and veterinary health. Proteolytic enzymes play crucial roles in the insect physiology including the modulation of embryonic development and food digestion. Therefore, these enzymes represent important targets for the development of new control strategies. This study presents zymographic characterization and comparative analysis of the proteolytic activity found in eggs, larval instars and pupae of Culex quinquefasciatus. Methods The proteolytic profiles of eggs, larvae and pupa of Cx. quinquefasciatus were characterized by SDS-PAGE co-polymerized with 0.1% gelatin, according to the pH, temperature and peptidase inhibitor sensitivity. In addition, the proteolytic activities were characterized in solution using 100 μM of the fluorogenic substrate Z-Phe-Arg-AMC. Results Comparison of the proteolytic profiles by substrate-SDS-PAGE from all preimaginal stages of the insect revealed qualitative and quantitative differences in the peptidase expression among eggs, larvae and pupae. Use of specific inhibitors revealed that the proteolytic activity from preimaginal stages is mostly due to trypsin-like serine peptidases that display optimal activity at alkaline pH. In-solution, proteolytic assays of the four larval instars using the fluorogenic substrate Z-Phe-Arg-AMC in the presence or absence of a trypsin-like serine peptidase inhibitor confirmed the results obtained by substrate-SDS-PAGE analysis. The trypsin-like serine peptidases of the four larval instars were functional over a wide range of temperatures, showing activities at 25°C and 65°C, with an optimal activity between 37°C and 50°C. Conclusion The combined use of zymography and in-solution assays, as performed in this study, allowed for a more detailed analysis of the

  15. Control of human filarial vector, Culex quinquefasciatus Say 1823 (Diptera:Culicidae) through bioactive fraction of Cayratia trifolia leaf

    Institute of Scientific and Technical Information of China (English)

    Sumanta Chakraborty; Someshwar Singha; Kuntal Bhattacharya; Goutam Chandra

    2013-01-01

    Objective:To investigate the mosquito larvicidal activity of Cayratia trifolia (L.) Domin (Vitaceae:Vitales) (C. trifolia) which is distributed in many parts of India with medicinal properties as vector control is facing threat due to the emergence of resistance to synthetic insecticides. Methods:Young and mature leaves of C. trifolia were investigated for larvicidal activity against 3rd instars larvae of Culex quinquefasciatus in different seasons throughout the year. The active fractions were extracted using six different solvents in a non-polar to polar fashion viz petroleum-ether, benzene, chloroform:methanol (1:1 v/v), acetone, absolute alcohol and distilled water. Dose dependent mortality was recorded against each solvent extract. Determination of LD50 and LD90 were executed through log-probit analysis using the most bioactive fraction. The fluctuations in mortality were statistically co-related through ANOVA analyses concerning different seasons and types of leaves as random variables. Justification of larvicidal activity was established through student’s t-test. Costing effects were evaluated on the non-target water fauna under laboratory conditions. Thin layer chromatographic techniques were performed for phytochemical analysis and categorization of chemical personality of the active fractions using the most effective solvent extract following standard methods. Results:Significant variations in mortality rate were noted with respect to the type of leaves (mature and senescence), concentration of leaf extract and between seasons. The water extract among all the solvent extracts was found to induce cent percent mortality at 50 mg/L in test mosquito species within 24 h with a LD50 and LD90 value of 10.70 mg/L and 27.64 mg/L respectively. No significant mortality was recorded in non-target water population. Chromatographic analyses of the water extract revealed the presence of steroids, triterpene glycosides, essential oil, phenolics and diterpenes as

  16. Control of human filarial vector, Culex quinquefasciatus Say 1823 (Diptera: Culicidae) through bioactive fraction of Cayratia trifolia leaf

    Science.gov (United States)

    Chakraborty, Sumanta; Singha, Someshwar; Bhattacharya, Kuntal; Chandra, Goutam

    2013-01-01

    Objective To investigate the mosquito larvicidal activity of Cayratia trifolia (L.) Domin (Vitaceae: Vitales) (C. trifolia) which is distributed in many parts of India with medicinal properties as vector control is facing threat due to the emergence of resistance to synthetic insecticides. Methods Young and mature leaves of C. trifolia were investigated for larvicidal activity against 3rd instars larvae of Culex quinquefasciatus in different seasons throughout the year. The active fractions were extracted using six different solvents in a non-polar to polar fashion viz petroleum-ether, benzene, chloroform: methanol (1:1 v/v), acetone, absolute alcohol and distilled water. Dose dependent mortality was recorded against each solvent extract. Determination of LD50 and LD90 were executed through log-probit analysis using the most bioactive fraction. The fluctuations in mortality were statistically co-related through ANOVA analyses concerning different seasons and types of leaves as random variables. Justification of larvicidal activity was established through student's t-test. Costing effects were evaluated on the non-target water fauna under laboratory conditions. Thin layer chromatographic techniques were performed for phytochemical analysis and categorization of chemical personality of the active fractions using the most effective solvent extract following standard methods. Results Significant variations in mortality rate were noted with respect to the type of leaves (mature and senescence), concentration of leaf extract and between seasons. The water extract among all the solvent extracts was found to induce cent percent mortality at 50 mg/L in test mosquito species within 24 h with a LD50 and LD90 value of 10.70 mg/L and 27.64 mg/L respectively. No significant mortality was recorded in non-target water population. Chromatographic analyses of the water extract revealed the presence of steroids, triterpene glycosides, essential oil, phenolics and diterpenes as

  17. LINKAGE OF KNOCKDOWN RESISTANCE AND THE SODIUM CHANNEL GENE MUTATION IN CULEX PIPIENS PALLENS *%淡色库蚊(Culex pipiens Pallens)与击倒抗性(kdr)相关的钠通道基因突变

    Institute of Scientific and Technical Information of China (English)

    宋锋林; 赵彤言; 董言德; 曹晓梅; 张晓龙

    2005-01-01

    本研究采用RT-PCR技术,使用简并引物分别从淡色库蚊(Culex pipiens pallens)敏感品系和抗溴氰菊酯品系中扩增出钠通道ⅡS4~ⅡS6区域的基因片段,长度为359bp.该基因片段所编码的氨基酸与黑尾果蝇(Drosophila melanogaster)、家蝇(Musca domestica)、埃及伊蚊(Aedes aegypti)、冈比亚按蚊(Anopheles gambiae)及德国小蠊(Blattella germanica)等昆虫相应区域的氨基酸序列具有较高的同源性,其同源性分别为95.8%,95.0%,100.0%,98.3%和95.0%.经序列比对,确认抗溴氰菊酯品系淡色库蚊钠通道基因在1014位点发生了突变:该位点的碱基"A"突变为"T",其对应氨基酸由亮氨酸(L)变为苯丙氨酸(F),该突变(L1014F型)在多种昆虫中较为常见.

  18. Single-reversal charge in the β10-β11 receptor-binding loop of Bacillus thuringiensis Cry4Aa and Cry4Ba toxins reflects their different toxicity against Culex spp. larvae.

    Science.gov (United States)

    Visitsattapongse, Sarinporn; Sakdee, Somsri; Leetacheewa, Somphob; Angsuthanasombat, Chanan

    2014-07-25

    Bacillus thuringiensis Cry4Aa toxin was previously shown to be much more toxic to Culex mosquito-larvae than its closely related toxin - Cry4Ba, conceivably due to their sequence differences within the β10-β11 receptor-binding loop. Here, single-Ala substitutions of five residues (Pro(510), Thr(512), Tyr(513), Lys(514) and Thr(515)) within the Cry4Aa β10-β11 loop revealed that only Lys(514) corresponding to the relative position of Cry4Ba-Asp(454) is crucial for toxicity against Culex quinquefasciatus larvae. Interestingly, charge-reversal mutations at Cry4Ba-Asp(454) (D454R and D454K) revealed a marked increase in toxicity against such less-susceptible larvae. In situ binding analyses revealed that both Cry4Ba-D454R and D454K mutants exhibited a significant increase in binding to apical microvilli of Culex larval midguts, albeit at lower-binding activity when compared with Cry4Aa. Altogether, our present data suggest that a positively charged side-chain near the tip of the β10-β11 loop plays a critical role in determining target specificity of Cry4Aa against Culex spp., and hence a great increase in the Culex larval toxicity of Cry4Ba was obtained toward an opposite-charge conversion of the corresponding Asp(454).

  19. The diapause program impacts renal excretion and molecular expression of aquaporins in the northern house mosquito, Culex pipiens.

    Science.gov (United States)

    Yang, Liu; Denlinger, David L; Piermarini, Peter M

    2016-12-27

    Adult females of the mosquito Culex pipiens entering diapause increase sugar water ingestion and reduce evaporative water loss, but how these attributes of the diapause program impact activity of the renal excretory system remains unknown. Here we compared the renal excretory capacity of diapausing and non-diapausing females, as well as the molecular expression of aquaporin (AQP) genes that encode channels involved in transporting water and/or small metabolites. Baseline urine excretion rates in diapausing mosquitoes were higher than in those of their non-diapausing counterparts, possibly a consequence of the intense sugar feeding associated with diapause. But, diapausing mosquitoes exhibited a much lower capacity for diuresis than non-diapausing mosquitoes. The suppressed diuretic capacity likely reflects reduced investment in the energetically-expensive post-prandial diuresis, an event not observed in diapausing mosquitoes. The mRNA expression levels of two genes encoding AQPs, Eglp1 and Aqp12L, in diapausing mosquitoes were down-regulated (on day 14) and up-regulated (on both days 3 and 14), respectively, in whole body samples. These changes were not evident in the excretory system (i.e., Malpighian tubules and hindgut), which showed no differential expression of AQPs as a function of diapause. Several AQP mRNAs were, however, differentially expressed in the midgut, ovaries, and abdominal body wall of diapausing mosquitoes, suggesting that AQPs in these tissues may be playing important non-excretory roles that are unique to diapause physiology.

  20. Insecticide susceptibility in larval populations of the West Nile vector Culex pipiens L.(Diptera: Culicidae) in Saudi Arabia

    Institute of Scientific and Technical Information of China (English)

    Al Thabiani Aziz; Jazem Abdullah Mahyoub; Hasibur Rehman; Shalini Saggu; Kadarkarai Murugan; Chellasamy Panneerselvam; Majed Salum S.Alrefaei; Marcello Nicoletti; Hui Wei; Angelo Canale; Giovanni Benelli

    2016-01-01

    Objective: To investigate the susceptibility to some conventional and non-conventional insecticides in laboratory and field larval populations of the West Nile vector Culex pipiens L.(Cx. pipiens), the dominant species in Jeddah Province, Saudi Arabia.Methods: The tested conventional insecticides were Actikil and Pesgard, while the nonconventional ones were Bacilod, Dudim and Baycidal. Probit analysis and photomicroscopical observations were carried out to shed light on acute toxicity in laboratory and field Cx. pipiens strains.Results: Cx. pipiens were more susceptible to Pesgard(LC50: 0.045 and 0.032 mg/L)than Actikil(0.052 and 0.038 mg/L) and Bacilod(0.129 and 0.104 mg/L), for the field and laboratory strains, respectively. Results showed that treatments with the chitin synthesis inhibitor Dudim and Baycidal evoked morphological effects similar to those induced by other insect growth regulators. According to IC50 values obtained(concentration which to inhibit the emergence of 50% of mosquito adults), the compound Dudim(0.000 3 and 0.000 1 mg/L) was more effective against Cx. pipiens L. mosquitoes than Baycidal(0.000 4 and 0.000 3 mg/L) for both the field and laboratory strains, respectively.Conclusions: Our results provide baseline data to enhance control programs and orient public health decisions on the selection of pesticides against mosquito vectors in Saudi Arabia.

  1. Efficacy of fipronil combined with permethrin commercial spot on (Effitix) preventing Culex pipiens from feeding on dogs.

    Science.gov (United States)

    Franc, Michel; Lienard, Emmanuel; Jacquiet, Philippe; Bonneau, Stephane; Bouhsira, Emilie

    2015-06-01

    A controlled clinical trial was carried out to assess the adulticidal and anti-feeding effectiveness of a spot-on combining fipronil and permethrin (Effitix, Virbac, Carros, France) in preventing Culex pipiens from feeding on dogs. Twelve dogs with equal sensitivity to mosquitoes were included in the study and divided into two groups of six dogs: an untreated control group and a group treated with Effitix. All dogs were challenged with 80 females C. pipiens for 90 ± 5 min on days -7, 1, 7, 14, 21, and 28 (day 0 being treatment day). The number of engorged, dead, and live mosquitoes was determined after each exposure to treated and untreated dogs. Dead mosquitoes were also counted 24 h after exposure. The anti-feeding effect of the spot-on formulation was 100, 99.5, 97.7, 98.3, and 96.7% on days 1, 7, 14, 21, and 28, respectively. The mortality effect was 66.6, 55.9, 38, 17.2, and 12.3% on days 1, 7, 14, 21, and 28, respectively. At each challenge point, the mortality and anti-feeding effects on mosquitoes were significantly different between the control and treated group (p < 0.05). The results indicate that a combination of permethrin and fipronil could be used as an effective mosquito control strategy in dogs and is therefore recommended for use in a dirofilariasis prevention program.

  2. Laboratory evaluation of selected larvicides and insect growth regulators against field-collected Culex quinquefasciatus larvae from urban Dhaka, Bangladesh.

    Science.gov (United States)

    Ali, A; Chowdhury, M A; Hossain, M I; Mahmud-Ul-Ameen; Habiba, D B; Aslam, A F

    1999-03-01

    Five organophosphates (OPs) (chlorpyrifos, chlorpyrifos methyl, fenthion, malathion, and temephos), 3 pyrethroids (bifenthrin, cypermethrin, and permethrin), 1 phenyl pyrazole (fipronil), 2 microbial pesticides (Bacillus thuringiensis serovar. israelensis [B.t.i.] and Bacillus sphaericus), and 3 insect growth regulators (IGRs) (diflubenzuron, methoprene, and pyriproxyfen) were evaluated against field-collected Culex quinquefasciatus larvae from urban Dhaka, Bangladesh. The LC90 values of all OPs, except for temephos (LC90 = 0.0096 ppm), were high, ranging from 0.13 ppm (fenthion) to 2.882 ppm (chlorpyrifos methyl). Pyrethroid LC90 values were 0.021 ppm (bifenthrin), 0.00061 (cypermethrin), and 0.017 ppm (permethrin). Fipronil exhibited a superior activity with LC90 value of 0.000896 ppm. Technical powders of B.t.i. and B. sphaericus (VectoBac TP and VectoLex TP) were considered highly effective against the Cx. quinquefasciatus larvae. The IGRs also were effective with pyriproxyfen (LC90 = 0.0011 ppm), being 3 times and 47 times more active than diflubenzuron (LC90 = 0.0034 ppm) and methoprene (LC90 = 0.052 ppm), respectively. In general, toxicity ranking of chemicals and microbials tested was phenyl pyrazole > IGRs > pyrethroids > microbials > OPs.

  3. Immunization with Culex tarsalis mosquito salivary gland extract modulates West Nile virus infection and disease in mice.

    Science.gov (United States)

    Machain-Williams, Carlos; Reagan, Krystle; Wang, Tian; Zeidner, Nordin S; Blair, Carol D

    2013-02-01

    Mosquito salivary proteins inoculated during blood feeding modulate the host immune response, which can contribute to the pathogenesis of viruses transmitted by mosquito bites. Previous studies with mosquito bite-naïve mice indicated that exposure to arthropod salivary proteins resulted in a shift toward a Th2-type immune response in flavivirus-susceptible mice but not flavivirus-resistant animals. In the study presented here, we tested the hypothesis that immunization with high doses of Culex tarsalis salivary gland extracts (SGE) with an adjuvant would prevent Th2 polarization after mosquito bite and enhance resistance to mosquito-transmitted West Nile virus (WNV). Our results indicate that mice immunized with Cx. tarsalis SGE produced increased levels of Th1-type cytokines (IFNγ and TNFα) after challenge with mosquito-transmitted WNV and exhibited both a delay in infection of the central nervous system (CNS) and significantly lower WNV brain titers compared to mock-immunized mice. Moreover, mortality was significantly reduced in the SGE-immunized mice, as none of these mice died, compared to mortality of 37.5% of mock-vaccinated mice by 8 days after infected mosquito bite. These results suggest that development of a mosquito salivary protein vaccine might be a strategy to control arthropod-borne viral pathogens such as WNV.

  4. Behavioral responses of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus against various synthetic and natural repellent compounds.

    Science.gov (United States)

    Sathantriphop, Sunaiyana; White, Sabrina A; Achee, Nicole L; Sanguanpong, Unchalee; Chareonviriyaphap, Theeraphap

    2014-12-01

    The behavioral responses of colony populations of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus to four essential oils (citronella, hairy basil, catnip, and vetiver), two standard repellents (DEET and picaridin), and two synthetic pyrethroids (deltamethrin and permethrin) were conducted in the laboratory using an excito-repellency test system. Results revealed that Cx. quinquefasciatus and An. minimus exhibited much stronger behavioral responses to all test compounds (65-98% escape for contact, 21.4-94.4% escape for non-contact) compared to Ae. aegypti (3.7-72.2% escape (contact), 0-31.7% (non-contact)) and Ae. albopictus (3.5-94.4% escape (contact), 11.2-63.7% (non-contact)). In brief, essential oil from vetiver elicited the greatest irritant responses in Cx. quinquefasciatus (96.6%) and An. minimus (96.5%) compared to the other compounds tested. The synthetic pyrethroids caused a stronger contact irritant response (65-97.8% escape) than non-contact repellents (0-50.8% escape for non-contact) across all four mosquito species. Picaridin had the least effect on all mosquito species. Findings from the current study continue to support the screening of essential oils from various plant sources for protective properties against field mosquitoes. © 2014 The Society for Vector Ecology.

  5. Merida virus, a putative novel rhabdovirus discovered in Culex and Ochlerotatus spp. mosquitoes in the Yucatan Peninsula of Mexico.

    Science.gov (United States)

    Charles, Jermilia; Firth, Andrew E; Loroño-Pino, Maria A; Garcia-Rejon, Julian E; Farfan-Ale, Jose A; Lipkin, W Ian; Blitvich, Bradley J; Briese, Thomas

    2016-04-01

    Sequences corresponding to a putative, novel rhabdovirus [designated Merida virus (MERDV)] were initially detected in a pool of Culex quinquefasciatus collected in the Yucatan Peninsula of Mexico. The entire genome was sequenced, revealing 11 798 nt and five major ORFs, which encode the nucleoprotein (N), phosphoprotein (P), matrix protein (M), glycoprotein (G) and RNA-dependent RNA polymerase (L). The deduced amino acid sequences of the N, G and L proteins have no more than 24, 38 and 43 % identity, respectively, to the corresponding sequences of all other known rhabdoviruses, whereas those of the P and M proteins have no significant identity with any sequences in GenBank and their identity is only suggested based on their genome position. Using specific reverse transcription-PCR assays established from the genome sequence, 27 571 C. quinquefasciatus which had been sorted in 728 pools were screened to assess the prevalence of MERDV in nature and 25 pools were found positive. The minimal infection rate (calculated as the number of positive mosquito pools per 1000 mosquitoes tested) was 0.9, and similar for both females and males. Screening another 140 pools of 5484 mosquitoes belonging to four other genera identified positive pools of Ochlerotatus spp. mosquitoes, indicating that the host range is not restricted to C. quinquefasciatus. Attempts to isolate MERDV in C6/36 and Vero cells were unsuccessful. In summary, we provide evidence that a previously undescribed rhabdovirus occurs in mosquitoes in Mexico.

  6. Experimental hut evaluation of the pyrrole insecticide chlorfenapyr on bed nets for the control of Anopheles arabiensis and Culex quinquefasciatus.

    Science.gov (United States)

    Mosha, F W; Lyimo, I N; Oxborough, R M; Malima, R; Tenu, F; Matowo, J; Feston, E; Mndeme, R; Magesa, S M; Rowland, M

    2008-05-01

    To determine the efficacy of chlorfenapyr against Anopheles arabiensis and Culex quinquefasciatus in East Africa and to identify effective dosages for net treatment in comparison with the commonly used pyrethroid deltamethrin. Chlorfenapyr was evaluated on bed nets in experimental huts against A. arabiensis and C. quinquefasciatus in Northern Tanzania, at application rates of 100-500 mg/m(2). In experimental huts, mortality rates in A. arabiensis were high (46.0-63.9%) for all dosages of chlorfenapyr and were similar to that of deltamethrin-treated nets. Mortality rates in C. quinquefasciatus were higher for chlorfenapyr than for deltamethrin. Despite a reputation for being slow acting, >90% of insecticide-induced mortality in laboratory tunnel tests and experimental huts occurred within 24 h, and the speed of killing was no slower than for deltamethrin-treated nets. Chlorfenapyr induced low irritability and knockdown, which explains the relatively small reduction in blood-feeding rate. Combining chlorfenapyr with a more excito-repellent pyrethroid on bed nets for improved personal protection, control of pyrethroid-resistant mosquitoes and pyrethroid resistance management would be advantageous.

  7. Mosquito larvicidal and ovicidal properties of Pithecellobium dulce (Roxb. Benth. (Fabaceae against Culex quinquefasciatus Say (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Govindarajan Marimuthu

    2014-04-01

    Full Text Available Objective: 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 (P. dulce against filariasis vector mosquito, Culex quinquefasciatus (Cx. quinquefasciatus. Methods: Twenty five early third instar larvae of Cx. quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using the protocol of WHO (2005. The larval mortality was observed after 24 h of treatment. The ovicidal activity was determined against Cx. quinquefasciatus mosquito eggs to various concentrations ranging from 100-750 mg/L under the laboratory conditions. Results: The methanol extract of the leaves and seed of P. dulce was the most effective against the larvae with LC 50 and LC90 values 164.12 mg/L, 214.29 mg/L, 289.34 mg/L and 410.18 mg/L being observed after 24 h of exposure. The efficacy of methanol was followed by that of the ethyl acetate, chloroform, benzene and hexane extracts. The mean percent hatchability of the egg rafts were observed after 48 h of treatment. About 100% mortality was observed at 500 mg/L for leaf and 750 mg/L for seed methanol extracts of P. dulce. Conclusions: From the results, it can be concluded that the larvicidal and ovicidal effect of P. dulce against Cx. quinquefasciatus make this plant product promising as an alternative to synthetic insecticide in mosquito control programs.

  8. Mosquito larvicidal properties of Impatiens balsamina (Balsaminaceae against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Marimuthu Govindarajan

    2014-03-01

    Full Text Available Objective: To assess the larvicidal potential of the crude benzene, chloroform, ethyl acetate and methanol solvent extracts of the medicinal plant Impatiens balsamina against Anopheles stephensi (An. stephensi, Aedes aegypti (Ae. aegypti and Culex quinquefasciatus (Cx. quinquefasciatus. Methods: Twenty five third instar larvae of An. stephensi, Ae. aegypti and Cx. quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using the protocol recommended by WHO. The larval mortality was observed after 24 h of treatment. Results: Among extracts tested, the highest larvicidal activity was observed in leaf methanol extract of Impatiens balsamina against An. stephensi, Ae. aegypti and Cx. quinquefasciatus with the LC50 and LC90 values 98.04, 119.68, 125.06 and 172.93, 210.14, 220.60 mg/L, respectively. Conclusions: From the results it can be concluded that the larvicidal effect of Impatiens balsamina against An. stephensi, Ae. aegypti and Cx. quinquefasciatus make this plant product promising as an alternative to synthetic insecticide in mosquito control programs.

  9. Bioinsecticide and leaf litter combination increases oviposition and reduces adult recruitment to create an effective ovitrap for Culex mosquitoes.

    Science.gov (United States)

    Bellile, Katie G; Vonesh, James R

    2016-06-01

    Mosquito egg traps, aquatic habitats baited with oviposition attractant and insecticide, are important tools for surveillance and control efforts in integrated vector management programs. The bioinsecticide Bacillus thuringiensis subsp. israelensis (Bti) is increasingly used as an environmentally friendly alternative to chemical insecticides and the combination of Bti with a simple oviposition attractant like leaf litter to create an effective egg trap seems appealing. However, previous research suggests that Bti may itself alter oviposition, and that leaf litter may dramatically reduce Bti toxicity. Here we present results from field experiment designed to link the effects of litter and Bti on mosquito oviposition habitat selection and post-colonization survival to production of adult mosquitoes. Tripling litter increased Culex spp. oviposition nearly nine-fold, while Bti had no effect on oviposition. Neither factor altered egg survival, thus larval abundance reflected the effects of litter on oviposition. Both Bti and litter reduced larval survival by ∼60%. We found no evidence that increased litter reduced Bti toxicity. Adult production was dependent upon both litter and Bti. In the absence of Bti, effects of litter on oviposition translated into three-fold more adults. However, in the presence of Bti, initial increases in oviposition were erased by the combined negative effects of Bti and litter on post-colonization survival. Thus, our study provides field evidence that combined litter and Bti application creates an effective ovitrap. This combined treatment had the highest oviposition and the lowest survival, and thus removed the greatest number of mosquitoes from the landscape.

  10. Larvicidal activity of a toxin from the seeds of Jatropha curcas Linn. against Aedes aegypti Linn. and Culex quinquefasciatus Say.

    Science.gov (United States)

    Chanthakan, Nuchsuk; Nuanchawee, Wetprasit; Sittiruk, Roytrakul; Sunanta, Ratanapo

    2012-06-01

    The larvicidal effects of the crude protein extract and purified toxin, Jc-SCRIP, from the seed coat of Jatropha curcas Linn. against the third instar larvae of mosquitoes, Aedes aegypti Linn. and Culex quinquefasciatus Say, were investigated. This test compared the effects of the purified toxin with crude protein extracts from seed kernels of J. curcas and Ricinus communis. At various concentrations of purified toxin and crude protein extract, the larval mortality of both Ae. aegypti and Cx. quinquefasciatus were positively correlated with increased exposure time. The larvae of Cx. quinquefasciatus were more susceptible to the toxin and both extracts than the larvae of Ae. aegypti. After 24 hours of exposure, the extract showed larvicidal activity against Ae. aegypti and Cx. quinquefasciatus with (LC50) values of 3.89 mg/ml and 0.0575 mg/ml, respectively. The toxin, Jc-SCRIP, showed larvicidal activity against Ae. aegypti and Cx. quinquefasciatus with (LC50) values of 1.44 mg/ml and 0.0303 mg/ ml, respectively. These results indicated that the crude protein extract and Jc-SCRIP were more toxic to the third instar larvae of Cx. quinquefasciatus than that of Ae. aegypti. The potent larvicidal activities of the seed coat extract and the Jc-SCRIP toxin from J. curcas suggest that they may be used as bioactive agents to control the mosquito population.

  11. Insecticidal and repellent activity of Clausena dentata (Rutaceae) plant extracts against Aedes aegypti and Culex quinquefasciatus mosquitoes (Diptera: Culicidae).

    Science.gov (United States)

    Ramkumar, Govindaraju; Karthi, Sengodan; Muthusamy, Ranganathan; Natarajan, Devarajan; Shivakumar, Muthugounder Subramanian

    2015-03-01

    Mosquito control is facing a threat due to the emergence of resistance to synthetic insecticides. Insecticides of botanical origin may serve as suitable alternative biocontrol agents. The present study is to evaluate adulticidal activity of Clausena dentata plant extract against Aedes aegypti and Culex quinquefasciatus mosquitoes. The adult mortality was observed after 24 h of exposure. The highest mortality was found in acetone extracts against Ae. aegypti and Cx. quinquefasciatus with the LC50 and LC90 4.1783 mg/ml (3.8201-7.1026), 9.3884 mg/ml (7. 8258-13.1820) and 4.2451 mg/ml (3.8547-8.0254), 12.3214 mg/ml (10.9287-16.2220), respectively. Smoke toxicity was observed at 10-min interval for 40 min, and the mortality data were recorded. Result shows that Ae. aegypti and Cx. quinquefasciatus are 85 ± 2 and 89 ± 1.5, respectively. A mortality of 100 % was recorded in the commercial mosquito control. These results suggest that the leaf extracts of C. dentata have a potential to be used as an ideal eco-friendly approach for the control of mosquitoes.

  12. Mosquito larvicidal and ovicidal properties of Pithecellobium dulce (Roxb.) Benth. (Fabaceae) against Culex quinquefasciatus Say (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Govindarajan Marimuthu; Rajeswary Mohan

    2014-01-01

    Objective: To assess the larvicidal and ovicidal potential of the crude hexane, benzene, chloroform, ethyl acetate and methanol solvent extracts from the medicinal plant, Pithecellobiumdulce (P. dulce) against filariasis vector mosquito, Culex quinquefasciatus (Cx. quinquefasciatus). Methods: Twenty five early third instar larvae of Cx. quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using the protocol of WHO (2005). The larval mortality was observed after 24 h of treatment. The ovicidal activity was determined against Cx.quinquefasciatus mosquito eggs to various concentrations ranging from 100-750 mg/L under the laboratory conditions.Results:The methanol extract of the leaves and seed of P. dulce was the most effective against the larvae with LC50 and LC90 values 164.12 mg/L, 214.29 mg/L, 289.34 mg/L and 410.18 mg/L being observed after 24 h of exposure. The efficacy of methanol was followed by that of the ethyl acetate, chloroform, benzene and hexane extracts. The mean percent hatchability of the egg rafts were observed after 48 h of treatment. About 100% mortality was observed at 500 mg/L for leaf and 750 mg/L for seed methanol extracts of P. dulce.Conclusions:From the results, it can be concluded that the larvicidal and ovicidal effect of P. dulce against Cx. quinquefasciatus make this plant product promising as an alternative to synthetic insecticide in mosquito control programs.

  13. Influence of light and habitat on predation of Culex quinquefasciatus (Diptera: Culicidae) larvae by the waterbugs(Hemiptera: Heteroptera)

    Institute of Scientific and Technical Information of China (English)

    Nabaneeta Saha; Gautam Aditya; Animesh Bal; Goutam K. Saha

    2008-01-01

    The influence of light and habitat structure on the predation of Culex quinquefasciatus larvae by the common heteropteran water bug, Diplonychus (= Sphaerodema)annulatus, D. rusticus and Anisops bouvieri was assessed in the laboratory. It was revealed that water bugs predate more in presence of light than in dark conditions. While A. bouvieri consumed more prey in structured conditions, D. annulatus and D. rusticus consumed more prey in open conditions. The selection of prey size as well as the respective numbers varied between predators and treatments significantly. Prey vulnerability (PV), an indicator of predatory efficiency, was highest for D. annulatus, moderate for D. rusticus and low forA.bouvieri. Prey consumption and PV values under different treatment conditions indicate that for belostomatid water bugs D. annulatus and D. rusticus, the order of prey consumption under different habitat and light/dark combinations is light open > dark open > light vegetated > dark vegetated. In the case of the backswimmer, A. bouvieri, the order of prey consumption appeared to be light structured > dark structured > light open > dark open. These findings were consistent with resource-partitioning by water bug species sharing the same guild. If the observed results are extended to natural settings the efficiency of these predators in controlling mosquito populations will vary with the structural complexity of habitats and the intensity of light.

  14. REPELLENT EFFECT OF OCIMUM BASILICUM AND GLYCYRRHIZA GLABRA EXTRACTS AGAINST THE MOSQUITO VECTOR, CULEX PIPIENS (DIPTERA: CULICIDAE).

    Science.gov (United States)

    Hassan, Mostafa I; Hammad, Kotb M; Saeed, Saeed M

    2015-08-01

    Essential or volatile oils of plants have been variously reported to have many medicinal applications. Methanol, acetone and petroleum ether extracts of Ocimum basilicum and Glycyrrhiza glabra were screened for their repellency effect against Culex pipiens mosquito. The repellent action of the present plants extracts were varied depending on the solvent used and dose of extract. Methanol extract of O. basilicum exhibited the lowest repellent activity as it recorded 77.4% at 6.7mg/cm2. The petroleum ether and acetone extract of 0. basilicum showed repellency of 98.1 & 84.6% respectively, at dose of 6.7mg/cm2, while methanolic extract of G. glabra recorded 73.8 & 50.3% at dose of 6.7 &1.7mg/cm2 respectively, the petroleum ether and acetone extract of G. glabra showed repellency of 76.3 & 81.6%, respectively at dose of 6.7mg/cm2, compared with the commercial formulation, N.N. diethyl toulamide (DEET) which exhibited 100% repellent action at dose of 1.8mg/cm2, respectively. The results may contribute to design an alternative way to control mosquitoes currently based on applications of synthetic insecticides. These extracts could be developed commercially as an effective personal protection meaure against mosquito bites and thus to control diseases caused by mosquito-borne pathogens.

  15. Synthesis of eco-friendly silver nanoparticles from Morinda tinctoria leaf extract and its larvicidal activity against Culex quinquefasciatus.

    Science.gov (United States)

    Kumar, K Ramesh; Nattuthurai, N; Gopinath, Ponraj; Mariappan, Tirupathi

    2015-02-01

    Mosquitoes are the major vector for the transmission of malaria, dengue fever, yellow fever, filariasis, chikungunya and Japanese encephalitis, and they accounted for global mortality and morbidity with increased resistance to common insecticides. The aim of this study was to investigate the larvicidal potential of the acetone leaf extracts of Morinda tinctoria and synthesized silver nanoparticles against third instar larvae of Culex quinquefasciatus Say (Diptera: Culicidae). Nanoparticles are being used in many commercial applications. It was found that aqueous silver ions can be reduced by aqueous extract of plant parts to generate extremely stable silver nanoparticles in water. Synthesized AgNPs were characterized by ultraviolet-visible (UV-vis) spectroscopy, Atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FT-IR) analysis. The synthesized silver nanoparticles have also been tested against the third instar larvae of C. quinquefasciatus. The leaf extract and the AgNPs high mortality values were 50 % lethal concentration (LC50) = 8.088 and 1.442 ppm against C. quinquefasciatus, respectively. The results recorded from ultraviolet-visible spectroscopy, atomic force microscopy and Fourier transform infrared spectroscopy support the biosynthesis and characterization of silver nanoparticles. These results suggest that the leaf extract of M. tinctoria and synthesis of AgNPs have the potential to be used as an ideal eco-friendly approach for the control of C. quinquefasciatus. By this approach, it is suggestive that this rapid synthesis of nanoparticles would be proper for developing a biological process for mosquito control.

  16. Irritability Levels of Field and Laboratory Population of Culex pipiens Complex in Tehran to Different Groups of Insecticides

    Science.gov (United States)

    Rahimi, Sara; Vatandoost, Hassan; Abai, Mohammad Reza; Raeisi, Ahmad; Hanafi-Bojd, Ahmad Ali; Rafi, Fatemeh

    2016-01-01

    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. PMID:27308276

  17. Mosquito larvicidal and ovicidal activity of puffer fish extracts against Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Samidurai, Kaliyaperumal; Mathew, Nisha

    2013-03-01

    The extracts of liver (LE), ovary (OE), skin (SE) and muscle (ME) tissues of four species of puffer fishes viz., Arothron hispidus, Lagocephalus inermis, Lagocephalus scleratus and Chelonodon patoca were evaluated against larvae and eggs of three mosquito vectors, Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti. The LC50 values were 1194.26, 1382.73 (LE); 1421.42, 1982.73 (OE); 7116.86, 15038.98 (ME) and 10817.8 ppm (SE) for An. stephensi and Cx. quinquefasciatus respectively for A. hispidus. In the case of L. inermis, the LC50 values were 1163.83, 1556.1 and 2426.38 (LE); 1653.53, 2734.74 (OE); 6067.47 (ME) and 10283.04 ppm (SE) for An. stephensi, Cx. quinquefasciatus and Ae. aegypti respectively. The LC50 values were 1509.98, 1608.69 (LE) and 1414.9, 2278.69 ppm (OE) for An. stephensi and Cx. quinquefasciatus respectively for the extracts of L. scleratus. In the case C. patoca extracts the LC50 values were 1182.29, 1543.00, 2441.03 (LE) and 1076.13, 2582.11 ppm (OE) for An. stephensi, Cx. quinquefasciatus and Ae. aegypti respectively. OE and LE of all puffer fishes exhibited zero percent egg hatchability from 600 to 1000 ppm against eggs of An. stephensi and Cx. quinquefasciatus. This study shows that puffer toxins are effective in killing the larvae and eggs of mosquitoes.

  18. Mosquito larvicidal and biting deterrency activity of bud of Polianthes tuberosa plants extract against Anopheles stephensi and Culex quinquefasciatus

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    Anjali Rawani

    2012-06-01

    Full Text Available Objective: To evaluate the larvicide and biting deterrency activity of bud of Polianthes tuberosa (P. tuberosa against Culex quinquefasciatus (Cx. quinquefasciatus and Anopheles stephensi (An. stephensi. Methods: Crude and solvent extract [ethyl acetate, chloroform: methanol (1:1, v/v, acetone] of fresh, mature, bud of P. tuberosa was tested against Cx. quinquefasciatus and An. stephensi. The repellent activity tested by chloroform: methanol (1:1, v/v solvent extract against both mosquito species. The appropriate lethal concentrations at 24 h for chloroform: methanol (1:1, v/v extract was also studied on non target organisms such as Toxorhynchites larvae, Diplonychus annulatum and Chironomus circumdatus. Results: In a 72 h bioassay experiment, 0.5 % crude extract showed the highest mortality and chloroform: methanol (1:1, v/v solvent extract showed the highest mortality, the maximum (P < 0.05 mortality was recorded at a concentration of 60 mg/L. The chloroform: methanol (1:1, v/v solvent extract provide 4 h protection against Cx. quinquefasciatus and 5 h against An. stephensi from biting. Conclusions: Both crude and chloroform: methanol (1:1, v/v extract showed efficient activity against Cx. quinquefasciatus, so it could be used as a mosquito larvicide agent. There is no change in the activity of non-target organism so, it is safe to use.

  19. Bioefficacy of plant-mediated gold nanoparticles and Anthocepholus cadamba on filarial vector, Culex quinquefasciatus (Insecta: Diptera: Culicidae).

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    Kumar, A Naresh; Jeyalalitha, T; Murugan, K; Madhiyazhagan, P

    2013-03-01

    Mosquito-borne diseases in India, e.g., malaria, dengue, chikungunya, filariasis, and Japanese encephalitis cause thousands of deaths per year. Mosquito control is to enhance the health and quality of life of county residents and visitors through the reduction of mosquito populations. Mosquito control is of serious concern in developing countries like India due to the lack of general awareness, development of resistance, and socioeconomic reasons. Noble metal nanoparticles have been used because of their unique optical properties; especially gold and silver have a broad absorption band in the visible region of electromagnetic spectrum. Synthesis of gold nanoparticles using Cymbopogan citratus is an ecofriendly approach for safer environment. C. citratus leaf broth was a good reducing agent that converted chloroauric acid (HAuCl(4)) to metal gold and further heating converted it into nanoparticles. Characterization using UV spectrophotometer, X-ray diffraction, Fourier transform infrared spectroscopy, particle size analyzer, and transmission electron microscopy confirmed that the particles are gold nanoparticles ranging between 10 and 110 nm with an average particles size of 20 nm. Further biosynthesized gold nanoparticles and Anthocephalus cadamba were experimented for the larvicidal effect on the filarial vector, Culex quinquefasciatus. Results showed that the gold nanoparticles are much toxic than the plant extract. Observed lethal concentrations (LC(50) and LC(90)) were 1.08 and 2.76 ppm for gold nanoparticles and 21.82 and 79.52 ppm for the third instar of C. quinquefasciatus.

  20. Preparation of Ecofriendly Formulations Containing Biologically Active Monoterpenes with Their Fumigant and Residual Toxicities against Adults of Culex pipiens

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    Mohamed E. I. Badawy

    2016-01-01

    Full Text Available Different mixtures of monoterpenes (ketone, alcohol, and alkene were loaded on paper discs and wax and their knockdown activities were evaluated against Culex pipiens adults. Some individual monoterpenes were also evaluated by residual toxicity technique. Citronella oil as a reference was also loaded separately or in combination with monoterpenes on paper discs and wax. The ketone monoterpenes mixture (camphor, menthone, carvone, and fenchone on paper discs was the most active (KT50 = 17.20 min followed by ketone monoterpenes with citronella oil (KT50 = 20.79 min and citronella oil alone (KT50 = 28.72 min. Wax formulations proved that the ketone and alcohol (geraniol, thymol, and menthol monoterpenes gave the most activity as knockdown (KT50 = 31.79 and 43.39 min, resp.. Alcohol monoterpenes formulation recorded KT50 = 43.39 min. Residual activity of tested individual monoterpenes reported that the menthol was more toxic than camphor and camphene. Generally, this study suggests that the monoterpenes have the properties, which make them used as eco-friendly compounds in the control programs of Cx. pipiens adult. The use of paper discs is more applicable than wax in the adulticidal formulations.

  1. Effect of environmental temperature on the ability of Culex pipiens (Diptera: Culicidae) to transmit West Nile virus.

    Science.gov (United States)

    Dohm, David J; O'Guinn, Monica L; Turell, Michael J

    2002-01-01

    Environmental temperature can affect the ability of mosquitoes to transmit an arbovirus. However, results of various studies indicate that these effects are not consistent among viruses or mosquito species, and there is no information available on the effect of environmental temperature on the ability of North American mosquito species to transmit West Nile (WN) virus. We evaluated the effect of incubation temperature (18, 20, 26, or 30 degrees C) on the ability of Culex pipiens L. derived from specimens collected during the outbreak in New York in 1999 to transmit a strain of WN virus obtained from a crow that died during this outbreak. Although mosquitoes fed on the same viremic chickens, infection rates were directly related to subsequent incubation temperatures. In mosquitoes held at 30 degrees C, virus was recovered from nearly all mosquitoes tested, disseminated infections were detected as early as 4 d after the infectious blood meal, and >90% of all mosquitoes had a disseminated infection 12 or more days after the infectious blood meal. In contrast, for mosquitoes held at 18 degrees C, disseminated infections were not detected until 25 d after the infectious blood meal, and even after 28 d, <30% contained a disseminated infection. Results for mosquitoes held at 20 and 26 degrees C were intermediate for both infection and dissemination rates. The effect of environmental temperature should to be considered when evaluating the vector competence of these mosquitoes and modeling risk of WN virus transmission in nature.

  2. Potential larvicidal and pupacidal activities of herbal essential oils against Culex quinquefasciatus say and Anopheles minimus (Theobald).

    Science.gov (United States)

    Phasomkusolsil, Siriporn; Soonwera, Mayura

    2010-11-01

    The larvicidal and pupacidal effects of eight herbal essential oils were tested against third instar (L3), fourth instar (L4), and pupal stages of Culex quinquefasciatus and Anopheles minimus. Probit analysis was used to analyze the data. The larval mortality was recorded at 1, 5, 10, 30, and 60 minutes, and 24 hours. Pupal mortality was also recorded at 24 hours intervals for 96 hours when completed mortality was achieved. Citronella grass oil #2 (Cymbopogon nardus) proved to have the greatest toxicity against 3rd instar Cx. quinquefasciatus and An. minimus with LT50 at 1.2 and <0.2 minute, respectively. It exhibited a high level of effectiveness against 4th instar Cx. quinquefasciatus (LT50 at 5.1 minutes) and An. minimus (LT50 at 0.9 minute). Regarding pupacidal activity, Cx. quinquefasciatus and An. minimus pupae were susceptible to Lemon grass oil (LT50 at 1.2 hours) and Citronella grass oil #1 (LT50 at 0.6 hour), respectively. These oils had larvicidal and pupacidal activities with 100% mortality against L3, L4 and pupal stage Cx. quinquefasciatus at 10 minutes, 30 minutes and 24 hours. They also caused 100% mortality of An. minimus at 5 minutes (L3, L4), and 24 hours (pupal stage).

  3. High prevalence and lineage diversity of avian malaria in wild populations of great tits (Parus major and mosquitoes (Culex pipiens.

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    Olivier Glaizot

    Full Text Available Avian malaria studies have taken a prominent place in different aspects of evolutionary ecology. Despite a recent interest in the role of vectors within the complex interaction system of the malaria parasite, they have largely been ignored in most epidemiological studies. Epidemiology of the disease is however strongly related to the vector's ecology and behaviour, and there is a need for basic investigations to obtain a better picture of the natural associations between Plasmodium lineages, vector species and bird hosts. The aim of the present study was to identify the mosquito species involved in the transmission of the haemosporidian parasites Plasmodium spp. in two wild populations of breeding great tits (Parus major in western Switzerland. Additionally, we compared Plasmodium lineages, based on mitochondrial DNA cytochrome b sequences, between the vertebrate and dipteran hosts, and evaluated the prevalence of the parasite in the mosquito populations. Plasmodium spp. were detected in Culex pipiens only, with an overall 6.6% prevalence. Among the six cytochrome b lineages of Plasmodium identified in the mosquitoes, three were also present in great tits. The results provide evidence for the first time that C. pipiens can act as a natural vector of avian malaria in Europe and yield baseline data for future research on the epidemiology of avian malaria in European countries.

  4. High prevalence and lineage diversity of avian malaria in wild populations of great tits (Parus major) and mosquitoes (Culex pipiens).

    Science.gov (United States)

    Glaizot, Olivier; Fumagalli, Luca; Iritano, Katia; Lalubin, Fabrice; Van Rooyen, Juan; Christe, Philippe

    2012-01-01

    Avian malaria studies have taken a prominent place in different aspects of evolutionary ecology. Despite a recent interest in the role of vectors within the complex interaction system of the malaria parasite, they have largely been ignored in most epidemiological studies. Epidemiology of the disease is however strongly related to the vector's ecology and behaviour, and there is a need for basic investigations to obtain a better picture of the natural associations between Plasmodium lineages, vector species and bird hosts. The aim of the present study was to identify the mosquito species involved in the transmission of the haemosporidian parasites Plasmodium spp. in two wild populations of breeding great tits (Parus major) in western Switzerland. Additionally, we compared Plasmodium lineages, based on mitochondrial DNA cytochrome b sequences, between the vertebrate and dipteran hosts, and evaluated the prevalence of the parasite in the mosquito populations. Plasmodium spp. were detected in Culex pipiens only, with an overall 6.6% prevalence. Among the six cytochrome b lineages of Plasmodium identified in the mosquitoes, three were also present in great tits. The results provide evidence for the first time that C. pipiens can act as a natural vector of avian malaria in Europe and yield baseline data for future research on the epidemiology of avian malaria in European countries.

  5. Evaluation of Some Plant Fruit Extracts for the Control of West Nile Virus Vector Culex pipiens (Diptera: Culicidae)

    Science.gov (United States)

    Koc, Samed; Evren, Ozay Hasan; Cetin, Huseyin

    2016-01-01

    Background: The extracts of different parts of plants were found very effective against various pests. The aim of this research was to determine the insecticidal activity of fruit methanol extracts obtained from Melia azedarach (Meliaceae), Phoenix theophrasti (Arecaceae), Styphnolobium japonicum (Fabaceae) and Pyracantha coccinea (Rosaceae) against the larvae of Culex pipiens (Diptera: Culicidae). Methods: The fruits of test plants were collected from the Campus of Akdeniz University, Antalya, Turkey in 2013. A series of concentrations of the extracts ranging from 62.5–1000 ppm were tested against second instar larvae. Results: Only the extracts of Me. azedarach and Ph. theoprasti showed significant larvicidal activity against Cx. pipiens and the LC50 values of these extracts were found to be 169.48 and 220.60 ppm, respectively. This is the first research investigating the insecticidal or larvicidal activity of Ph. theophrasti, St. japonicum and Py. coccinea extracts on mosquitoes. Conclusion: The methanol extract of fruits of Me. azedarach and Ph. theophrasti showed significantly higher larvicidal activity against Cx. pipiens. PMID:28032112

  6. CONTROL OF THE BREEDING OF CULEX LARVAE IN SEWAGE WELLS BY THE USE OF ABATE, 5c

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    P.Sanajian

    1973-09-01

    Full Text Available In order to determine the control of breeding sources of Culex larvae in sewage wells by the larvicide Abate, some studies were performed in the summer and autumn of 1972. In general, it was noticed in these studies that:1. The wells chosen as a control (5 wells were active throughout the study periods and adult mosquitoes were captured plentifully. 2 In 4 sewage wells which were controlled by kerosene, after the distribution of kerosene the number of adults diminished and in some cases reached zero or near zero. These studies showed that the use of kerosene at ½ to one liter for each well is able to control the production source of mosquitoes for 10 to 12 days.3. Abate capsules were investigated at various quantities. In a number of wells, one capsule was used at the beginning; it was observed that, in some cases, there were not many effects on the mosquito population. The next time, 2 capsules were used and it was noticed that the density of adult mosquitoes decreased considerably and reached zero. In some cases, some of these wells had no activity for mosquito production for 30 days. In some of the other wells, 2 capsules were used initially and it was observed that the density reached zero after 6-7 days, and they then remain zero for 20 to 22 days. In general, these studies showed that the Abate capsule is a larvicide in sewage wells and that can control larvae.

  7. Mosquito larvicidal and biting deterrency activity of bud of Polianthes tuberosa plants extract against Anopheles stephensi and Culex quinquefasciatus.

    Science.gov (United States)

    Anjali, Rawani; Atanu, Banerjee; Goutam, Chandra

    2012-06-01

    Mosquito control by phytochemicals is an alternative method to synthetic insecticides, as it is biodegradable and non resistant to vector mosquito. Polianthes tuberosa is a perennial plant distributed in many parts of India. The present study was undertaken to scientifically evaluate the larvicide and biting deterrency activity of bud of Polianthes tuberosa against Culex quinquefasciatus and Anopheles stephensi. Crude and solvent extract [ethyl acetate, chloroform: methanol (1:1, v/v), acetone] of fresh, mature, bud of P. tuberosa was tested against (ex. quinquefasciatus and An. stephensi. The repellent activity tested by chloroform: methanol (1:1, v/v) solvent extract against both mosquito species. The appropriate lethal concentrations at 24h for chloroform: methanol (1:1, v/v) extract was also studied on non target organisms such as Toxorhynchites larvae, Diplonychus annulatum and Chironomus circumdatus. In a 72 hour bioassay experiment, 0.5% crude extract showed the highest mortality and chloroform: methanol (1:1, v/v) solvent extract showed the highest mortality, the maximum (p larvicide agent. There is no changes in the activity non-target organism so, it is safe to use.

  8. Ovicidal and larvicidal activities of some plant extracts against Aedes aegypti L. and Culex quinquefasciatus Say (Diptera: Culicidae

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    Rajiv Gandhi Munusamy

    2016-06-01

    Full Text Available Objective: To evaluate the ovicidal and larvicidal activities of hexane, chloroform and methanol extracts of Gymnema sylvestre, Scilla peruvina, Rubia cordifolia (R. cordifolia and Elytraria acaulis roots against the eggs and larvae of Aedes aegypti L. (Ae. aegypti and Culex quinquefasciatus Say (Cx. quinquefasciatus at different concentrations of 62.5, 125, 250 and 500 mg/L. Methods: The plant materials were shade dried in the laboratory for one week and then coarsely powdered. The root powder of each plant (500 g was sequentially soaked in hexane, chloroform and methanol for 96 h with intermittent shaking. After 96 h, the solution was filtered and the filtrate was concentrated under reduced pressure by using rotary vacuum evaporator. All the crude extracts thus obtained were stored in air tight glass vials and Petri dishes. Results: The ovicidal activity results showed that the methanol extract of R. cordifolia root was the most potent compared to other with 82.40% and 70.40% activity against the eggs of Cx. quinquefasciatus and Ae. aegypti, respectively, at 500 mg/L concentration similarly, methanol extract of R. cordifolia root also recorded the highest larvicidal activity with LC50 and LC90 values of 95.69, 347.96 mg/L against Cx. quinquefasciatus and 102.23, 350.20 mg/L against Ae. aegypti larvae, respectively. Conculsions: Hence, methanol extract of R. cordifolia root can be probed further for effective biological control of mosquitoes.

  9. Some observations on overwintering sites of adult Culex quinquefasciatus (Diptera: Culicidae) and strategies followed under natural and seminatural conditions.

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    Thareja, V; Singh, Rangoli; Singha Naorem, Anjana

    2016-01-01

    Field population of adult Culex quinquefasciatus Say, landed in December, congregated and overwintered in indoor artificial sites in Delhi. Repeated sampling strategy by individually collecting the adults was adopted to study their overwintering strategies for 4 years (December to April). They remained vagile and readily repopulated the resting sites after the removal of samples. A large percentage of females was fertile, unfed and nulliparous indicating that reproduction ceased in them. Adult survival was significantly prolonged to a maximum of 3 months under natural conditions. Gonotrophic cycle also got prolonged. Close to quitting, they became gravid and left in April without oviposition. No adults were observed on the sites for the rest of the year. Oviposition was induced in the blood-engorged females when provided with food, water and outdoor conditions. Oviposition might have been induced directly by water and food provided them energy under seminatural conditions. Eggs were laid singly or in the form of rafts, and the number in both the cases was low. Singly laid eggs did not hatch, and in rafts, hatching was ~80 %. Winter conditions seemed to strongly impact fertility, blood feeding, fecundity, oviposition behaviour, egg hatchability and longevity. Use of the overwintering sites as biological tool, as a part of environmental control in IPM, is suggested for organising antivector measures during winter. There is a need of exploring and creating more sites of this kind.

  10. The role of miR-2∼13∼71 cluster in resistance to deltamethrin in Culex pipiens pallens.

    Science.gov (United States)

    Guo, Qin; Huang, Yun; Zou, Feifei; Liu, Bingqian; Tian, Mengmeng; Ye, Wenyun; Guo, Juxin; Sun, Xueli; Zhou, Dan; Sun, Yan; Ma, Lei; Shen, Bo; Zhu, Changliang

    2017-05-01

    Excessive and continuous application of deltamethrin has resulted in the development of deltamethrin resistance among mosquitoes, which becomes a major obstacle for mosquito control. In a previous study, differentially expressed miRNAs between deltamethrin-susceptible (DS) strain and deltamethrin-resistant (DR) strain using illumina sequencing in Culex pipiens pallens were identified. In this study, we applied RNAi and the Centers for Disease Control and Prevention (CDC) bottle bioassay to investigate the relationship between miR-2∼13∼71 cluster (miR-2, miR-13 and miR-71) and deltamethrin resistance. We used quantitative real-time PCR (qRT-PCR) to measure expression levels of miR-2∼13∼71 clusters. MiR-2∼13∼71 cluster was down regulated in adult female mosquitoes from the DR strain and played important roles in deltamethrin resistance through regulating target genes, CYP9J35 and CYP325BG3. Knocking down CYP9J35 and CYP325BG3 resulted in decreased mortality of DR mosquitoes. This study provides the first evidence that miRNA clusters are associated with deltamethrin resistance in mosquitoes. Moreover, we investigated the regulatory networks formed between miR-2∼13∼71 cluster and its target genes, which provide a better understanding of the mechanism involved in deltamethrin resistance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Juvenile hormone (JH esterase of the mosquito Culex quinquefasciatus is not a target of the JH analog insecticide methoprene.

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    Shizuo G Kamita

    Full Text Available Juvenile hormones (JHs are essential sesquiterpenes that control insect development and reproduction. JH analog (JHA insecticides such as methoprene are compounds that mimic the structure and/or biological activity of JH. In this study we obtained a full-length cDNA, cqjhe, from the southern house mosquito Culex quinquefasciatus that encodes CqJHE, an esterase that selectively metabolizes JH. Unlike other recombinant esterases that have been identified from dipteran insects, CqJHE hydrolyzed JH with specificity constant (k(cat/K(M ratio and V(max values that are common among JH esterases (JHEs. CqJHE showed picomolar sensitivity to OTFP, a JHE-selective inhibitor, but more than 1000-fold lower sensitivity to DFP, a general esterase inhibitor. To our surprise, CqJHE did not metabolize the isopropyl ester of methoprene even when 25 pmol of methoprene was incubated with an amount of CqJHE that was sufficient to hydrolyze 7,200 pmol of JH to JH acid under the same assay conditions. In competition assays in which both JH and methoprene were available to CqJHE, methoprene did not show any inhibitory effects on the JH hydrolysis rate even when methoprene was present in the assay at a 10-fold higher concentration relative to JH. Our findings indicated that JHE is not a molecular target of methoprene. Our findings also do not support the hypothesis that methoprene functions in part by inhibiting the action of JHE.

  12. Identification of differentially expressed microRNAs in Culex pipiens and their potential roles in pyrethroid resistance.

    Science.gov (United States)

    Hong, Shanchao; Guo, Qin; Wang, Weijie; Hu, Shengli; Fang, Fujin; Lv, Yuan; Yu, Jing; Zou, Feifei; Lei, Zhentao; Ma, Kai; Ma, Lei; Zhou, Dan; Sun, Yan; Zhang, Donghui; Shen, Bo; Zhu, Changliang

    2014-12-01

    Pyrethroids are the major class of insecticides used for mosquito control. Excessive and improper use of insecticides, however, has resulted in pyrethroid resistance, which has become a major obstacle for mosquito control. The development of pyrethroid resistance is a complex process involving many genes, and information on post-transcription regulation of pyrethroid resistance is lacking. In this study, we extracted RNA from mosquitoes in various life stages (fourth-instar larvae, pupae, male and female adult mosquitoes) from deltamethrin-sensitive (DS) and resistant (DR) strains. Using illumina sequencing, we obtained 13760296 and 12355472 reads for DS-strains and DR-strains, respectively. We identified 100 conserved miRNAs and 42 novel miRNAs derived from 21 miRNA precursors in Culex pipiens. After normalization, we identified 28 differentially expressed miRNAs between the two strains. Additionally, we found that cpp-miR-71 was significant down regulated in female adults from the DR-strain. Based on microinjection and CDC Bottle Bioassay data, we found that cpp-miR-71 may play a contributing role in deltamethrin resistance. The present study provides the firstly large-scale characterization of miRNAs in Cu. pipiens and provides evidence of post-transcription regulation. The differentially expressed miRNAs between the two strains are expected to contribute to the development of pyrethroid resistance. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Selection, Realized Heritability, and Fitness Cost Associated With Dimethoate Resistance in a Field Population of Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Alam, Mehboob; Waqas Sumra, Muhammad; Ahmad, Daniyal; Shah, Rizwan Mustafa; Binyameen, Muhammad; Ali Shad, Sarfraz

    2017-06-01

    Mosquitoes are known to be vectors of numerous diseases leading to human morbidity and mortality at large scale in the world. Insecticide resistance has become a serious concern in controlling the insect vectors of public health importance. Dimethoate is an organophosphate insecticide used to control different insect pests including mosquitoes. Biological parameters of susceptible, unselected, and dimethoate-selected strains of Culex quinquefasciatus Say were studied in the laboratory to recognize resistance development potential and associated fitness cost. The dimethoate-selected strain showed 66.48-fold resistance to dimethoate compared with the susceptible strain after three continuous selections of generations. Realized heritability estimates of dimethoate resistance in Cx. quinquefasciatus yielded a value of 0.19. In dimethoate-selected strain, the biological traits including larval weight, survival from first instar to pupae, fecundity, number of next-generation larvae, relative fitness, net reproductive rate, intrinsic rate of natural increase, and biotic potential were significantly reduced as compared with the unselected strain. However, adult longevity, mean relative growth rate, weight of egg raft, female ratio, pupal duration, and emergence rate of the dimethoate-selected strain did not differ significantly compared with that of the unselected strain. This study provides useful information to devise retrospective management strategy for dimethoate resistance in Cx. quinquefasciatus. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Oviposition responses of gravid female Culex quinquefasciatus to egg rafts and low doses of oviposition pheromone under semifield conditions.

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    Braks, Marieta A; Leal, Walter S; Cardé, Ring T

    2007-03-01

    Semifield experiments were conducted to study the oviposition of gravid Culex quinquefasciatus females in response to one or 10 egg rafts, or 3.0 microg of synthetic oviposition pheromone, (-)-(5R, 6S)-6-acetoxy-5-hexadecanolide, a dose equivalent to 10 egg rafts. These treatments were added to the small bowls filled with either hay infusion or water in a small (0.3-m spacing) or a large-square design (3.4-m spacing). Oviposition choice was more pronounced in the "small square" assays. Mean number of egg rafts laid in response to a single egg raft in an oviposition jar filled with hay infusion was significantly greater than with all other treatments. When the oviposition pheromone dose was increased from one to 10 rafts or when 3.0 microg synthetic oviposition pheromone were dispensed on a floating receptacle, synergistic effects were observed between the oviposition pheromone and the hay infusion at both distances. This study is the first demonstration that the amount in a single raft induces oviposition of gravid Cx. quinquefasciatus females under semi-natural conditions.

  15. Modeled response of the West Nile virus vector Culex quinquefasciatus to changing climate using the dynamic mosquito simulation model

    Science.gov (United States)

    Morin, Cory W.; Comrie, Andrew C.

    2010-09-01

    Climate can strongly influence the population dynamics of disease vectors and is consequently a key component of disease ecology. Future climate change and variability may alter the location and seasonality of many disease vectors, possibly increasing the risk of disease transmission to humans. The mosquito species Culex quinquefasciatus is a concern across the southern United States because of its role as a West Nile virus vector and its affinity for urban environments. Using established relationships between atmospheric variables (temperature and precipitation) and mosquito development, we have created the Dynamic Mosquito Simulation Model (DyMSiM) to simulate Cx. quinquefasciatus population dynamics. The model is driven with climate data and validated against mosquito count data from Pasco County, Florida and Coachella Valley, California. Using 1-week and 2-week filters, mosquito trap data are reproduced well by the model ( P climate projection data generated by the National Center for Atmospheric Research CCSM3 general circulation model, we applied temperature and precipitation offsets to the climate data at each location to evaluate mosquito population sensitivity to possible future climate conditions. We found that temperature and precipitation shifts act interdependently to cause remarkable changes in modeled mosquito population dynamics. Impacts include a summer population decline from drying in California due to loss of immature mosquito habitats, and in Florida a decrease in late-season mosquito populations due to drier late summer conditions.

  16. Evaluation of target specific larvicidal activity of the leaf extract of Typhonium trilobatum against Culex quinquefasciatus Say

    Institute of Scientific and Technical Information of China (English)

    Koyel Mallick Haldar; Papiya Ghosh; Goutam Chandra

    2011-01-01

    Objective: To investigate the target specific larvicidal potential of an edible herb Typhonium trilobatum (T. trilobatum) (L.) Schott against mosquito Culex quinquefasciatus (Cx. quinquefasciatus) Say. Methods: Different concentrations of crude and methanol extract of T. trilobatum mature leaves were treated against Cx. quinquefasciatus larvae. LC50 concentration of crude extract on mosquito 3rd instar larvae was tested on Chironomus circumdatus and Diplonychus annulatum larvae. Preliminary phytochemical analysis was performed in search of plant’s secondary metabolites. Results:100%mortality of 1st instar mosquito larvae was recorded at 0.4%concentration after 72 h of exposure of crude extract. At 72 h 0.5%concentration produced 100%, 89.99%and 79.99%mortality of 2nd, 3rd and 4th instar larvae respectively. 50 ppm methanol extract showed 73.67%mortality of 3rd instar mosquito larvae at 72 h. 400 ppm concentration was responsible for 100%mortality in 24 h. Application of LC50 concentration (of 3rd instar mosquito larva) against non target organisms like C. circumdatus and D. annulatum larvae produced no significant mortality among them. Secondary metabolites like terpenoids and free glycoside bound anthraquinones were found. Conclusions:This experimental study was a pioneer attempt to establish T. trilobatum as a valuable resource of effective target specific mosquito larvicide.

  17. A FIELD CONTROL TRIAL OF CULEX QUINQUEFASCIATUS LARVAE BY POLYMER FORMULATIONS OF OMS-786 AND OMS-971 IN JAKARTA

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    IG. Seregeg

    2012-09-01

    Full Text Available Suatu uji coba lapangan penggunaan larvisida OMS-971a (chlorpyrifos dan OMS-786b (temephos dalam formulasi lepas terkendali (controlled release formulation = CRF terhadap larva Culex quinquefasciatus telah dilakukan dalam selokan-selokan di Kampung Sunter, Jakarta Utara. Tidak ada penurunan yang nyata baik kerapatan larva maupun kerapatan pupa, segera setelah penebaran larvisida tersebut dalam dosis 1 ppm. Akan tetapi penurunan kerapatan larva baru terlihat selama satu sampai dua bulan sesudah penebaran. Pada penelitian ini chlorpyrifos terlihat sedikit lebih berpengaruh (effective dibandingkan dengan temephos. Pengaruh dari temephos" sa'nd granules" sebagai formulasi pem­banding hanya berlangsung paling lama satu minggu, pada penggunaan dosis sebesar lppm. Keadaan dasar selokan dengan endapan lumpur yang tebal diperkirakan telah melumpuhkan daya kerja temephos SG, yang langsung tenggelam ke dasar selokan setelah penebaran. Hal ini berbeda dengan formulasi chlorpyrifos dan temephos yang bersifat lepas terkendali (CRF, berada dalam suatu keadaan yang tetap mengapung di atas permukaan air. Chlorpyrifos dapat memberikan daya kendali terhadap larva sebesar 70 - 94% pada minggu ke 5-8 dan terhadap pupa sebesar 87% pada minggu ke 6 dan 92% pada minggu ke 7. Temephos CRF memberikan daya kendali terhadap larva sebesar 90-96 % pada minggu ke 4-8 dan menurun menjadi 75-96% pada minggu ke 8-9.

  18. Ovicidal and repellent activities of botanical extracts against Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Govindarajan M; Mathivanan T; Elumalai K; Krishnappa K; Anandan A

    2011-01-01

    Objective: To determine the ovicidal and repellent activities of methanol leaf extract ofErvatamia coronaria (E. coronaria) and Caesalpinia pulcherrima (C. pulcherrima) against Culex quinquefasciatus (Cx. quinquefasciatus), Aedes aegypti (Ae. aegypti) and Anopheles stephensi (An. stephensi). Methods: The ovicidal activity was determined against three mosquito species at various concentrations ranging from 50-450 ppm under the laboratory conditions. The hatch rates were assessed 48 h after treatment. The repellent efficacy was determined against three mosquito species at three concentrations viz., 1.0, 2.5 and 5.0 mg/cm2 under the laboratory conditions.Results:The crude extract of E. coronaria exerted zero hatchability (100% mortality) at 250, 200 and 150 ppm for Cx. quinquefasciatus, Ae. aegypti and An. stephensi, respectively. The crude extract of C. pulcherrima exerted zero hatchability (100% mortality) at 375, 300 and 225 ppm for Cx. quinquefasciatus, Ae. aegypti and An. Stephensi, respectively. The methanol extract of E. coronaria found to be more repellenct than C. pulcherrima extract. A higher concentration of 5.0 mg/cm2 provided 100% protection up to 150, 180 and 210 min against Cx. quinquefasciatus, Ae.aegypti and An. stephensi, respectively. The results clearly showed that repellent activity was dose dependent. Conclusions: From the results it can be concluded the crude extracts of E. coronaria and C. pulcherrima are an excellent potential for controlling Cx. quinquefasciatus, Ae. aegypti and An. stephensi mosquitoes.

  19. Larvicidal and repellent activity of tetradecanoic acid againstAedes aegypti (Linn.) andCulex quinquefasciatus (Say.) (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Sivakumar R; Jebanesan A; Govindarajan M; Rajasekar P

    2011-01-01

    Objective:To investigate the larvicidal and repellent efficacy of tetradecanoic acid against Aedes aegypti (Ae. aegypti) L. andCulex quinquefasciatus (Cx. quinquefasciatus) Say (Diptera: Culicidae).Methods: Larvicidal efficacy of tetradecanoic acid was tested at various concentrations against the early third instar larvae of Ae. aegypti andCx. quinquefasciatus. The repellent activity was determined against two mosquito species at three concentrations viz.,1.0,2.5 and5.0 ppm under the laboratory conditions.Results: The tetradecanoic acid was found to be more effective againstCx. quinquefasciatus thanAe. aegypti larvae. TheLC50values were14.08 ppm and25.10 ppm, respectively. Tetradecanoic acid showed lesser repellency againstAe. aegypti andCx. quinquefasciatus. The highest repellency was observed in higher concentration of5.0 mg/cm2provided100% protection up to60 and 90 min againstAe. aegypti andCx. quinquefasciatusrespectively.Conclusions: From the results it can be concluded the tetradecanoic acid is a potential for controlling Cx. quinquefasciatus andAe. aegypti mosquitoes.

  20. Mosquito larvicidal properties of Impatiens balsamina (Balsaminaceae) against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Marimuthu Govindarajan; Mohan Rajeswary

    2014-01-01

    Objective: To assess the larvicidal potential of the crude benzene, chloroform, ethyl acetate and methanol solvent extracts of the medicinal plant Impatiens balsamina against Anopheles stephensi(An. stephensi), Aedes aegypti (Ae. aegypti) and Culex quinquefasciatus (Cx. quinquefasciatus). Methods: Twenty five third instar larvae of An. stephensi, Ae. aegypti and Cx. quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using the protocol recommended by WHO. The larval mortality was observed after 24 h of treatment. Results: Among extracts tested, the highest larvicidal activity was observed in leaf methanol extract of Impatiens balsamina against An. stephensi, Ae. aegypti and Cx. quinquefasciatus with the LC50 and LC90 values 98.04, 119.68, 125.06 and 172.93, 210.14, 220.60 mg/L, respectively. Conclusions:From the results it can be concluded that the larvicidal effect of Impatiens balsamina against An. stephensi, Ae. aegypti and Cx. quinquefasciatus make this plant product promising as an alternative to synthetic insecticide in mosquito control programs.

  1. Relative toxicity of neem fruit, bitter gourd, and castor seed extracts against the larvae of filaria vector, Culex quinquefasciatus (Say).

    Science.gov (United States)

    Batabyal, Lata; Sharma, Preeti; Mohan, Lalit; Maurya, Prejwltta; Srivastava, C N

    2009-10-01

    In search of a natural larvicide, petroleum ether, carbon tetrachloride, and methanol extracts of Azadirachta indica fruits and seed extracts of bitter gourd (Momordica charantia) and castor (Ricinus communis) were tested for larvicidal activity against Culex quinquefasciatus. Among the extracts tested, the methanol extract of Az. indica was observed the most potent with LC(50) at 74.04 and 58.52 ppm and LC(-90) at 201.83 and 171.70 ppm as compared to methanol extract of M. charantia with LC(50) at 101.18 and 93.58 ppm and LC(90) at 322.81 and 302.62 ppm carbon tetrachloride extract of R. communis with LC(50) at 144.11 and 92.44 ppm and LC(90) at 432.42 and 352.89 ppm after 24 and 48 h, respectively. The methanol extract of Az. indica exhibited potential results and can be exploited as a preferred natural larvicide for the control of filarial vector, Cx. quinquefasciatus.

  2. Assessment of residual bio-efficacy and persistence of Ipomoea cairica plant extract against Culex quinquefasciatus Say mosquito.

    Science.gov (United States)

    Thiagaletchumi, Maniam; Zuharah, Wan Fatma; Ahbi Rami, Rattanam; Fadzly, Nik; Dieng, Hamady; Ahmad, Abu Hassan; AbuBakar, Sazaly

    2014-09-01

    Specification on residual action of a possible alternative insecticide derived from plant materials is important to determine minimum interval time between applications and the environmental persistence of the biopesticides. The objective of this study is to evaluate crude acethonilic extract of Ipomoea cairica leaves for its residual and persistence effects against Culex quinquefasciatus larvae. Wild strain of Cx. quinquefasciatus larvae were used for the purpose of the study. Two test designs, replenishment of water and without replenishment of water were carried out. For the first design, a total of 10 ml of test solution containing Ip. cairica extracts was replenished daily and replaced with 10 ml of distilled water. For the second design, treatment water was maintained at 1500 ml and only evaporated water was refilled. Larval mortality was recorded at 24 hours post-treatment after each introduction period and trials were terminated when mortality rate falls below 50%. Adult emergences from survived larvae were observed and number of survivals was recorded. For the non-replenishment design, mortality rate significantly reduced to below 50% after 28 days, meanwhile for replenishment of water declined significantly after 21 days (P water design. The short period of residual effectiveness of crude acethonilic extract of Ip. cairica leaves with high percentage of larval mortality on the first few days, endorses fewer concerns of having excess residues in the environment which may carry the risk of insecticide resistance and environmental pollution.

  3. Potential of biologically active plant oils to control mosquito larvae (Culex pipiens, Diptera: Culicidae) from an Egyptian locality.

    Science.gov (United States)

    Khater, Hanem Fathy; Shalaby, Afaf Abdel-Salam

    2008-01-01

    The insecticidal effect of six commercially available plant oils was tested against 4th larval instars of Culex pipiens. Larvae were originally collected from Meit El-Attar, Qalyubia Governorate, Egypt, and then reared in the laboratory until F1 generation. The LC50 values were 32.42, 47.17, 71.37, 83.36, 86.06, and 152.94 ppm for fenugreek (Trigonella foenum-grecum), earth almond (Cyperus esculentus), mustard (Brassica compestris), olibanum (Boswellia serrata), rocket (Eruca sativa), and parsley (Carum ptroselinum), respectively. The tested oils altered some biological aspects of C. pipiens, for instance, developmental periods, pupation rates, and adult emergences. The lowest concentrations of olibanum and fenugreek oils caused remarkable prolongation of larval and pupal durations. Data also showed that the increase of concentrations was directly proportional to reduction in pupation rates and adult emergences. Remarkable decrease in pupation rate was achieved by mustard oil at 1000 ppm. Adult emergence was suppressed by earth almond and fenugreek oils at 25 ppm. In addition, the tested plant oils exhibited various morphological abnormalities on larvae, pupae, and adult stages. Consequently, fenugreek was the most potent oil and the major cause of malformation of both larval and pupal stages. Potency of the applied plant oils provided an excellent potential for controlling C. pipiens.

  4. The Effect of West Nile Virus Infection on the Midgut Gene Expression of Culex pipiens quinquefasciatus Say (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Chelsea T. Smartt

    2016-12-01

    Full Text Available The interaction of the mosquito and the invading virus is complex and can result in physiological and gene expression alterations in the insect. The association of West Nile virus (WNV and Culex pipiens quinquefasciatus mosquitoes results in measurable changes in gene expression; 22 gene products were shown previously to have altered expression. Sequence analysis of one product, CQ G1A1, revealed 100% amino acid identity to gram negative bacteria binding proteins (CPQGBP in Cx. p. quinquefasciatus, Aedes aegypti (70% and Anopheles gambiae (63% that function in pathogen recognition. CQ G1A1 also was differentially expressed following WNV infection in two populations of Cx. p. quinquefasciatus colonized from Florida with known differences in vector competence for WNV and showed spatial and temporal gene expression differences in midgut, thorax, and carcass tissues. These data suggest gene expression of CQ G1A1 is influenced by WNV infection and the WNV infection-controlled expression differs between populations and tissues.

  5. Mtx toxins synergize Bacillus sphaericus and Cry11Aa against susceptible and insecticide-resistant Culex quinquefasciatus larvae.

    Science.gov (United States)

    Wirth, Margaret C; Yang, Yangkun; Walton, William E; Federici, Brian A; Berry, Colin

    2007-10-01

    Two mosquitocidal toxins (Mtx) of Bacillus sphaericus, which are produced during vegetative growth, were investigated for their potential to increase toxicity and reduce the expression of insecticide resistance through their interactions with other mosquitocidal proteins. Mtx-1 and Mtx-2 were fused with glutathione S-transferase and produced in Escherichia coli, after which lyophilized powders of these fusions were assayed against Culex quinquefasciatus larvae. Both Mtx proteins showed a high level of activity against susceptible C. quinquefasciatus mosquitoes, with 50% lethal concentrations (LC(50)) of Mtx-1 and Mtx-2 of 0.246 and 4.13 microg/ml, respectively. The LC(50)s were 0.406 to 0.430 microg/ml when Mtx-1 or Mtx-2 was mixed with B. sphaericus, and synergy improved activity and reduced resistance levels. When the proteins were combined with a recombinant Bacillus thuringiensis strain that produces Cry11Aa, the mixtures were highly active against Cry11A-resistant larvae and resistance was also reduced. The mixture of two Mtx toxins and B. sphaericus was 10 times more active against susceptible mosquitoes than B. sphaericus alone, demonstrating the influence of relatively low concentrations of these toxins. These results show that, similar to Cyt toxins from B. thuringiensis subsp. israelensis, Mtx toxins can increase the toxicity of other mosquitocidal proteins and may be useful for both increasing the activity of commercial bacterial larvicides and managing potential resistance to these substances among mosquito populations.

  6. Insecticide susceptibility in larval populations of the West Nile vector Culex pipiens L. (Diptera:Culicidae) in Saudi Arabia

    Institute of Scientific and Technical Information of China (English)

    Al Thabiani Aziz; Angelo Canale; Giovanni Benelli; Jazem Abdullah Mahyoub; Hasibur Rehman; Shalini Saggu; Kadarkarai Murugan; Chellasamy Panneerselvam; Majed Salum S Alrefaei; Marcello Nicoletti; Hui Wei

    2016-01-01

    Objective: To investigate the susceptibility to some conventional and non-conventional insecticides in laboratory and field larval populations of the West Nile vector Culex pipiens L. (Cx. pipiens), the dominant species in Jeddah Province, Saudi Arabia. Methods: The tested conventional insecticides were Actikil and Pesgard, while the non-conventional ones were Bacilod, Dudim and Baycidal. Probit analysis and photo-microscopical observations were carried out to shed light on acute toxicity in laboratory and field Cx. pipiens strains. Results: Cx. pipiens were more susceptible to Pesgard (LC50: 0.045 and 0.032 mg/L) than Actikil (0.052 and 0.038 mg/L) and Bacilod (0.129 and 0.104 mg/L), for the field and laboratory strains, respectively. Results showed that treatments with the chitin syn-thesis inhibitor Dudim and Baycidal evoked morphological effects similar to those induced by other insect growth regulators. According to IC50 values obtained (concen-tration which to inhibit the emergence of 50%of mosquito adults), the compound Dudim (0.000 3 and 0.000 1 mg/L) was more effective against Cx. pipiens L. mosquitoes than Baycidal (0.000 4 and 0.000 3 mg/L) for both the field and laboratory strains, respectively. Conclusions: Our results provide baseline data to enhance control programs and orient public health decisions on the selection of pesticides against mosquito vectors in Saudi Arabia.

  7. Larvicidal and pupicidal activity of extracts and fractionates of Eichhornia crassipes (Mart.) Solms against the filarial vector Culex quinquefasciatus Say.

    Science.gov (United States)

    Jayanthi, P; Lalitha, P; Aarthi, N

    2012-11-01

    Petroleum ether, acetone, ethyl acetate, aqueous extract, methanol and ethanol fractionate of Eichhornia crassipes (Mart.) Solms was tested for their larvicidal efficacy against the different instars (I, II, III and IV) and pupae of Culex quinquefasciatus Say. The larval mortality was observed after 24 h of the treatment. The extracts showed a dose-dependent toxicity to larvae. The toxicity of the extracts decreased with increase in larval stage. Ethanol fractionate of E. crassipes showed the highest larvicidal and pupicidal activity against C. quinquefasciatus compared to other solvent extracts and fractionates with LC(50) 71.43, 94.68,120.42, 152.15 and 173.35 ppm for I, II, III, IV and pupae, respectively. Presence of metabolites like flavonoids, alkaloids, anthroquinones and anthocyanins in the tested extracts might be the reason for the larvicidal and pupicidal activity of the plant extracts and fractionates of waterhyacinth. Mosquito-repellent activity was not exhibited by these extracts at the tested concentrations. The results demonstrated the potential of the aquatic plant E. crassipes in the successful control of the filarial vector C. quinquefasciatus.

  8. Identification of Culex pipiens complex mosquitoes in a hybrid zone of West Nile virus transmission in Fresno County, California.

    Science.gov (United States)

    McAbee, Rory D; Green, Emily N; Holeman, Jodie; Christiansen, Julie; Frye, Niki; Dealey, Katherine; Mulligan, F Steve; Brault, Aaron C; Cornel, Anthony J

    2008-02-01

    Culex pipiens sensu lato mosquitoes were collected from 24 gravid traps (mid-June to mid-October, 2005) in Fresno County, CA. Captured gravid females were allowed to oviposit before sibling species identification by Ace.2 PCR and detection of West Nile virus (WNV) RNA by RT-PCR were performed on the mother and her offspring. Of the 442 Cx. pipiens s.l. female mosquitoes collected, 88 were positive for WNV viral RNA (peaked in August) with no significant differences among complex members or habitat. Vertical transmission was detected in 4 out of 20 families originating from WNV-positive mothers, however, in only a small number of offspring from each family. Out of 101 families that had PCR-based maternal and offspring identifications, the offspring from 15 families produced inexplicable amplicon patterns, suggesting ambiguities in the PCR assay identifications. Male genitalia (DV/D ratio) and Ace.2 PCR identifications revealed numerous discrepancies in our ability to accurately determine the identity of Cx. pipiens complex members in the hybrid zone of Fresno County.

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

    Directory of Open Access Journals (Sweden)

    Marimuthu Govindarajan

    2014-02-01

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

  10. Application Site and Mosquito Age Influences Malathion- and Permethrin-Induced Mortality in Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Aldridge, Robert L; Kaufman, Phillip E; Bloomquist, Jeffrey R; Gezan, Salvador A; Linthicum, Kenneth J

    2017-09-06

    Concentrations of malathion and permethrin typical in droplets generated from ultra-low-volume and low-volume applications used to control mosquito populations were evaluated for efficacy against multiple-aged Culex quinquefasciatus Say (Diptera: Culicidae), using a topical bioassay. Although insecticide droplets will impinge on many exoskeletal body regions and a range of ages of mosquitoes in a population, traditional mosquito topical bioassays focus pesticide application to the mesothoracic pleural or dorsal regions across an average mosquito age (e.g., 3-7 d). Our results document nonuniform insecticide sensitivity across body regions at ages not previously assessed in mosquitoes (teneral and 14-d old). We expect our findings to influence the topical bioassay process, illustrating the difference in mosquito body regions and ages that ultimately may explain insecticide effectiveness wherever droplets impinge upon the mosquito body during field control applications. 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.

  11. Toxicity of Amorphigenin from the Seeds of Amorpha fruticosa against the Larvae of Culex pipiens pallens (Diptera: Culicidae

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    Yaping Liang

    2015-02-01

    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.

  12. Irritability Levels of Field and Laboratory Population of Culex pipiens Complex in Tehran to Different Groups of Insecticides

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    Sara Rahimi

    2016-01-01

    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.

  13. Ankyrin repeat domain-encoding genes in the wPip strain of Wolbachia from the Culex pipiens group

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    Parkhill Julian

    2007-09-01

    Full Text Available Abstract Background Wolbachia are obligate endosymbiotic bacteria maternally transmitted through the egg cytoplasm that are responsible for several reproductive disorders in their insect hosts, such as cytoplasmic incompatibility (CI in infected mosquitoes. Species in the Culex pipiens complex display an unusually high number of Wolbachia-induced crossing types, and based on present data, only the wPip strain is present. Results The sequencing of the wPip strain of Wolbachia revealed the presence of 60 ankyrin repeat domain (ANK encoding genes and expression studies of these genes were carried out in adult mosquitoes. One of these ANK genes, pk2, is shown to be part of an operon of three prophage-associated genes with sex-specific expression, and is present in two identical copies in the genome. Another homolog of pk2 is also present that is differentially expressed in different Cx. pipiens group strains. A further two ANK genes showed sex-specific regulation in wPip-infected Cx. pipiens group adults. Conclusion The high number, variability and differential expression of ANK genes in wPip suggest an important role in Wolbachia biology, and the gene family provides both markers and promising candidates for the study of reproductive manipulation.

  14. Evaluation of temephos and chlorpyrifos-methyl against Culex pipiens (Diptera: Culicidae) larvae in septic tanks in Antalya, Turkey.

    Science.gov (United States)

    Cetin, H; Yanikoglu, A; Kocak, O; Cilek, J E

    2006-11-01

    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.

  15. Observações sobre domiciliação de mosquitos Culex (Melanoconion, em ambiente com acentuadas modificações antrópicas Domiciliation of Culex (Melanoconion mosquitoes in man-made deeply modified environment

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    Oswaldo Paulo Forattini

    1991-08-01

    Full Text Available Estudam-se alguns aspectos do comportamento de espécies de Culex (Melanoconion em ambiente antrópico intensamente modificado. Foram realizadas coletas mensais de adultos, concomitantes e levadas a efeito no peridomicílio, em área aberta e em área coberta por vegetação de segunda formação. Foram focalizadas as espécies dominantes e representadas por Cx. delpontei, Cx. ocossa, Cx. ribeirensis, Cx. sacchettae e Cx. taeniopus. No peridomicílio, destacam-se pela regularidade de sua presença, Cx. ribeirensis e Cx. sacchettae, incluindo apreciável comparecimento às coletas com isca humana ali realizadas. A época de maior rendimento das capturas correspondeu ao primeiro trimestre, em especial modo, ao mês de março. Aliado a esse aspecto, Cx. ribeirensis e Cx. sacchettae revelaram apreciável freqüência à isca humana. Em relação a esta, o menor comparecimento foi apresentado por Cx. delpontei e Cx. ocossa. Quanto a Cx. taeniopus, compareceu de maneira um tanto irregular e em número geralmente inferior ao dos demais. As observações evidenciaram curva de atividade aumentando rapidamente por ocasião do início da noite e mantendo-se durante todo o período noturno, apresentada por Cx. ribeirensis, Cx. sacchettae e Cx. taeniopus. O outro tipo de curva foi observado com Cx. delpontei e Cx. ocossa, com aumento gradual na primeira metade da noite, alcançando o máximo ao redor da meia-noite, e declinando sensivelmente na segunda metade do período. As coletas de formas imaturas permitiram evidenciar criadouros de Cx. delpontei em cursos de água de porte médio ou grande, e associados à vegetação aquática flutuante. São feitas considerações de ordem ecológica passíveis de interpretar esses comportamentos de interesse epidemiológico.Some data on Culex (Melanoconion mosquito behavior in human environments are presented. Adults were collected simultaneously through peridomiciliary and extradomiciliary catches, with the use of

  16. How Diverse Detrital Environments Influence Nutrient Stoichiometry between Males and Females of the Co-Occurring Container Mosquitoes Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus

    Science.gov (United States)

    Yee, Donald A.; Kaufman, Michael G.; Ezeakacha, Nnaemeka F.

    2015-01-01

    Allocation patterns of carbon and nitrogen in animals are influenced by food quality and quantity, as well as by inherent metabolic and physiological constraints within organisms. Whole body stoichiometry also may vary between the sexes who differ in development rates and reproductive allocation patterns. In aquatic containers, such as tree holes and tires, detrital inputs, which vary in amounts of carbon and nitrogen, form the basis of the mosquito-dominated food web. Differences in development times and mass between male and female mosquitoes may be the result of different reproductive constraints, which could also influence patterns of nutrient allocation. We examined development time, survival, and adult mass for males and females of three co-occurring species, Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus, across environments with different ratios of animal and leaf detritus. We quantified the contribution of detritus to biomass using stable isotope analysis and measured tissue carbon and nitrogen concentrations among species and between the sexes. Development times were shorter and adults were heavier for Aedes in animal versus leaf-only environments, whereas Culex development times were invariant across detritus types. Aedes displayed similar survival across detritus types whereas C. quinquefasciatus showed decreased survival with increasing leaf detritus. All species had lower values of 15N and 13C in leaf-only detritus compared to animal, however, Aedes generally had lower tissue nitrogen compared to C. quinquefasciatus. There were no differences in the C:N ratio between male and female Aedes, however, Aedes were different than C. quinquefasciatus adults, with male C. quinquefasciatus significantly higher than females. Culex quinquefasciatus was homeostatic across detrital environments. These results allow us to hypothesize an underlying stoichiometric explanation for the variation in performance of different container species under similar

  17. Environmental factors associated with the distribution of Anopheles arabiensis and Culex quinquefasciatus in a rice agro-ecosystem in Mwea, Kenya.

    Science.gov (United States)

    Muturi, Ephantus J; Mwangangi, Joseph; Shililu, Josephat; Jacob, Benjamin G; Mbogo, Charles; Githure, John; Novak, Robert J

    2008-06-01

    Studies were conducted between May and June, 2006 to investigate the environmental factors affecting the distribution of An. arabiensis Patton and Culex quinquefasciatus Say in Mwea, Kenya. The sampling unit comprised all non-paddy aquatic habitats and ten randomly selected paddies and canals located within a 200 m radius from the periphery of the study site. Thirteen physico-chemical variables were recorded for each sampling site in each sampling occasion and a sample of mosquito larvae and other aquatic invertebrates collected. The non-paddy aquatic habitats identified included pools and marshes. Morphological identification of 1,974 mosquito larvae yielded four species dominated by Cx. quinquefasciatus (73.2%) and An. arabiensis (25.0%). Pools were associated with significantly higher Cx. quinquefasciatus larval abundance and less diversity of other aquatic invertebrates compared with other habitat types. In contrast, the abundance of An. arabiensis did not differ significantly among habitat types. Culex quinquefasciatus habitats had higher water conductivity and exhibited a higher abundance of other aquatic invertebrates than An. arabiensis habitats. Chi-square analysis indicated that the two species were more likely to coexist in the same habitats than would be expected by chance alone. Anopheles arabiensis larvae were positively associated with dissolved oxygen and adults of family Haliplidae and negatively associated with emergent vegetation and Heptageniidae larvae. Culex quinquefasciatus larvae were positively associated with dissolved oxygen, total dissolved solids, Chironomidae larvae, and Microvelidae adults and negatively associated with emergent vegetation. These findings suggest that both biotic and abiotic factors play a significant role in niche partitioning among Cx. quinquefasciatus and An. arabiensis, a factor that should be considered when designing an integrated vector control program.

  18. Aquatic microfauna alter larval food resources and affect development and biomass of West Nile and Saint Louis encephalitis vector Culex nigripalpus (Diptera: Culicidae).

    Science.gov (United States)

    Duguma, Dagne; Kaufman, Michael G; Simas Domingos, Arthur B

    2017-05-01

    Ciliate protists and rotifers are ubiquitous in aquatic habitats and can comprise a significant portion of the microbial food resources available to larval mosquitoes, often showing substantial declines in abundance in the presence of mosquito larvae. This top-down regulation of protists is reported to be strong for mosquitoes inhabiting small aquatic containers such as pitcher plants or tree holes, but the nature of these interactions with larval mosquitoes developing in other aquatic habitats is poorly understood. We examined the effects of these two microbial groups on lower trophic level microbial food resources, such as bacteria, small flagellates, and organic particles, in the water column, and on Culex larval development and adult production. In three independent laboratory experiments using two microeukaryote species (one ciliate protist and one rotifer) acquired from field larval mosquito habitats and cultured in the laboratory, we determined the effects of Culex nigripalpus larval grazing on water column microbial dynamics, while simultaneously monitoring larval growth and development. The results revealed previously unknown interactions that were different from the top-down regulation of microbial groups by mosquito larvae in other systems. Both ciliates and rotifers, singly or in combination, altered other microbial populations and inhibited mosquito growth. It is likely that these microeukaryotes, instead of serving as food resources, competed with early instar mosquito larvae for microbes such as small flagellates and bacteria in a density-dependent manner. These findings help our understanding of the basic larval biology of Culex mosquitoes, variation in mosquito production among various larval habitats, and may have implications for existing vector control strategies and for developing novel microbial-based control methods.

  19. Host-feeding patterns of Culex pipiens and other potential mosquito vectors (Diptera: Culicidae) of West Nile virus (Flaviviridae) collected in Portugal.

    Science.gov (United States)

    Osório, Hugo Costa; Zé-Zé, Líbia; Alves, Maria João

    2012-05-01

    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.

  20. How Diverse Detrital Environments Influence Nutrient Stoichiometry between Males and Females of the Co-Occurring Container Mosquitoes Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus.

    Directory of Open Access Journals (Sweden)

    Donald A Yee

    Full Text Available Allocation patterns of carbon and nitrogen in animals are influenced by food quality and quantity, as well as by inherent metabolic and physiological constraints within organisms. Whole body stoichiometry also may vary between the sexes who differ in development rates and reproductive allocation patterns. In aquatic containers, such as tree holes and tires, detrital inputs, which vary in amounts of carbon and nitrogen, form the basis of the mosquito-dominated food web. Differences in development times and mass between male and female mosquitoes may be the result of different reproductive constraints, which could also influence patterns of nutrient allocation. We examined development time, survival, and adult mass for males and females of three co-occurring species, Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus, across environments with different ratios of animal and leaf detritus. We quantified the contribution of detritus to biomass using stable isotope analysis and measured tissue carbon and nitrogen concentrations among species and between the sexes. Development times were shorter and adults were heavier for Aedes in animal versus leaf-only environments, whereas Culex development times were invariant across detritus types. Aedes displayed similar survival across detritus types whereas C. quinquefasciatus showed decreased survival with increasing leaf detritus. All species had lower values of 15N and 13C in leaf-only detritus compared to animal, however, Aedes generally had lower tissue nitrogen compared to C. quinquefasciatus. There were no differences in the C:N ratio between male and female Aedes, however, Aedes were different than C. quinquefasciatus adults, with male C. quinquefasciatus significantly higher than females. Culex quinquefasciatus was homeostatic across detrital environments. These results allow us to hypothesize an underlying stoichiometric explanation for the variation in performance of different container

  1. How Diverse Detrital Environments Influence Nutrient Stoichiometry between Males and Females of the Co-Occurring Container Mosquitoes Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus.

    Science.gov (United States)

    Yee, Donald A; Kaufman, Michael G; Ezeakacha, Nnaemeka F

    2015-01-01

    Allocation patterns of carbon and nitrogen in animals are influenced by food quality and quantity, as well as by inherent metabolic and physiological constraints within organisms. Whole body stoichiometry also may vary between the sexes who differ in development rates and reproductive allocation patterns. In aquatic containers, such as tree holes and tires, detrital inputs, which vary in amounts of carbon and nitrogen, form the basis of the mosquito-dominated food web. Differences in development times and mass between male and female mosquitoes may be the result of different reproductive constraints, which could also influence patterns of nutrient allocation. We examined development time, survival, and adult mass for males and females of three co-occurring species, Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus, across environments with different ratios of animal and leaf detritus. We quantified the contribution of detritus to biomass using stable isotope analysis and measured tissue carbon and nitrogen concentrations among species and between the sexes. Development times were shorter and adults were heavier for Aedes in animal versus leaf-only environments, whereas Culex development times were invariant across detritus types. Aedes displayed similar survival across detritus types whereas C. quinquefasciatus showed decreased survival with increasing leaf detritus. All species had lower values of 15N and 13C in leaf-only detritus compared to animal, however, Aedes generally had lower tissue nitrogen compared to C. quinquefasciatus. There were no differences in the C:N ratio between male and female Aedes, however, Aedes were different than C. quinquefasciatus adults, with male C. quinquefasciatus significantly higher than females. Culex quinquefasciatus was homeostatic across detrital environments. These results allow us to hypothesize an underlying stoichiometric explanation for the variation in performance of different container species under similar

  2. EFEKTIVITAS Bacillus thuringiensis H-14 STRAIN LOKAL DALAM BUAH KELAPA TERHADAP LARVA Anopheles sp dan Culex sp di KAMPUNG LAUT KABUPATEN CILACAP

    Directory of Open Access Journals (Sweden)

    Blondine Ch. P

    2013-07-01

    Full Text Available Abstrak Bacillus thuringiensis serotipe H-14 strain lokal adalah bakteri patogen bersifat target spesifiknya larva nyamuk, aman bagi mamalia dan lingkungan. Penelitian bertujuan menentukan efektivitas B. thuringiensis H-14 strain lokal yang dikembangbiakkan dalam buah kelapa untuk pengendalian larva Anopheles sp dan Culex sp. Rancangan eksperimental semu, terdiri dari kelompok perlakuan dan kontrol. Bacillus thuringiensis H-14 strain lokal dikembangbiakan dalam10 buah kelapa umur 6–8 bulan, dengan berat kira-kira 1 kg, telah berisi air kelapa sekitar 400-500 ml/buah kelapa yang diperoleh dari Desa Klaces, Kampung Laut, Kabupaten Cilacap. Diinkubasi selama 14 hari pada temperatur kamar dan ditebarkan di 6 kolam yang menjadi habitat perkembangbiakan larva nyamuk dengan luas berkisar 3–100 m2.Hasil yang diperoleh menunjukkan efektivitas B. thuringiensis H-14 strain lokal terhadap larva Anopheles sp dan Culex sp selama 1 hari sesudah penebaran kematian larva berturut-turut sebesar 80–100% dan 79,31–100%. Sedangkan pada hari ke-14 sebesar 69,30–76,71% dan 67,69–86,04%. Buah kelapa dapat digunakan sebagai media lokal alternatif untuk pengembangbiakan B. thuringiensis H-14 strain lokal Kata kunci: B. thuringiensis H-14,  strain  lokal, buah kelapa, pengendalian larva Abstract Bacillus thuringiensis serotype H-14 local strain is pathogenic bacteria which specific  target to mosquito larvae. It is safe for mammals and enviroment. The aims of this study was to determine the effectivity of B. thuringiensis H-14 local strain which culturing in thecoconut wates against Anopheles sp and Culex sp mosquito larvae. This research is quasi experiment which consist of treated  and control groups. Bacillus thuringiensis H-14 local strain was cultured in 10 coconuts with 6–8 months age with weight around 1 kg that contained were approximately 400-500 ml/coconut were taken from Klaces village, Kampung Laut. After that the coconuts incubated for 14

  3. 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).

    Science.gov (United States)

    Govindarajan, Marimuthu; Sivakumar, Rajamohan

    2014-04-01

    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

  4. Effects of gamma radiation on the activity of the mosquito culex pipiens L. II. Effects on the sexual vitality of the mosquito

    OpenAIRE

    El Banby, M. A. [محمد البنبي; Wakid, A. M.; Shoman, A. A.

    1988-01-01

    The effects of 3 gamma doses on the sex vitality of the mosquito Culex pipiens L. were studied after irradiation of the larvae, pupae or newly emerged adults. No significant effect on the sex attraction was obseived when irradiation was done at the larval or adult stages with 40 Gray. However, there was a clear effect of radiation at all doses tested on the attraction of males to females when they were irradiated in the pupal stage. At 80 and 120 Gray, there was a significant decrease, whe...

  5. Efficacy studies of Vectobac 12as and Teknar HP-D larvicides against 3rd-instar Ochlerotatus taeniorhynchus and Culex quinquefasciatus in small plot field studies.

    Science.gov (United States)

    Floore, T G; Petersen, J L; Shaffer, K R

    2004-12-01

    Efficacy studies were conducted with VectoBac 12AS and Teknar HP-D larvicides against 3rd-instar Ochlerotatus taeniorhynchus and Culex quinquefasciatus in small field test plots. The products were obtained off the shelf from distributors and had different lot numbers. They were evaluated over a 2-year period in spring 2002 and 2003. Application rates were 0.29, 0.58, and 1.10 liter/ha and evaluations were made 24 and 48 h after treatment. Both products performed well in these studies, with VectoBac 12AS being more effective at the 0.29 liter/ha rate.

  6. Evaluation of Pioneer eco-backpack sprayer and Twister XL backpack sprayer using Aqualuer against caged adult Aedes albopictus and Culex quinquefasciatus.

    Science.gov (United States)

    Xue, Rui-De; Qualls, Whitney A; Smith, Mike L; Zhao, Tong-Yan; Brown, James R

    2012-12-01

    A Pioneer Eco-Backpack electric cold ultra-low volume (ULV) sprayer and a gas-powered Twister XL 3950 series 2 motorized knapsack ULV sprayer with Aqualuer (20.6% permethrin AI) were evaluated against caged adult Aedes albopictus and Culex quinquefasciatus in St. Augustine, FL. The Pioneer Eco-Backpack sprayer provided 100% knockdown of both species of mosquitoes at 15 min; the Twister XL backpack sprayer resulted in 17-23% knockdown at 15 min. Both backpack sprayers with Aqualuer resulted in 100% mortality of both species at 24 h. The new Pioneer Eco-Backpack sprayer powered by electricity could be a potential tool for mosquito control.

  7. Differential effect of human ivermectin treatment on blood feeding Anopheles gambiae and Culex quinquefasciatus

    DEFF Research Database (Denmark)

    Derua, Yahya A.; Kisinza, William N.; Simonsen, Paul Erik

    2015-01-01

    BACKGROUND: Widespread and large scale use of ivermectin in humans and domestic animals can have unexpected effects on non-target organisms. As a search for a possible explanation for an observed longitudinal decline in density of anopheline vector mosquitoes, but not in Culex quinquefasciatus...... to receive either ivermectin or placebo. Twenty four hours after treatment, one volunteer from each group was concurrently exposed to 50 laboratory reared An. gambiae on one arm and 50 laboratory reared Cx. quinquefasciatus on the other arm for 15-30 minutes. Engorged mosquitoes were maintained on 10...

  8. Detection of Culex flavivirus and Aedes flavivirus nucleotide sequences in mosquitoes from parks in the city of São Paulo, Brazil.

    Science.gov (United States)

    Fernandes, Licia Natal; de Paula, Marcia Bicudo; Araújo, Alessandra Bergamo; Gonçalves, Elisabeth Fernandes Bertoletti; Romano, Camila Malta; Natal, Delsio; Malafronte, Rosely dos Santos; Marrelli, Mauro Toledo; Levi, José Eduardo

    2016-05-01

    The dengue viruses are widespread in Brazil and are a major public health concern. Other flaviviruses also cause diseases in humans, although on a smaller scale. The city of São Paulo is in a highly urbanized area with few green spaces apart from its parks, which are used for recreation and where potential vertebrate hosts and mosquito vectors of pathogenic Flavivirus species can be found. Although this scenario can contribute to the transmission of Flavivirus to humans, little is known about the circulation of members of this genus in these areas. In light of this, the present study sought to identify Flavivirus infection in mosquitoes (Diptera: Culicidae) collected in parks in the city of São Paulo. Seven parks in different sectors of the city were selected. Monthly mosquito collections were carried out in each park from March 2011 to February 2012 using aspiration and traps (Shannon and CD C-CO2). Nucleic acids were extracted from the mosquitoes collected and used for reverse-transcriptase and real-time polymerase chain reactions with genus-specific primers targeting a 200-nucleotide region in the Flavivirus NS5 gene. Positive samples were sequenced, and phylogenetic analyses were performed. Culex and Aedes were the most frequent genera of Culicidae collected. Culex flavivirus (CxFV)-related and Aedes flavivirus (AEFV)- related nucleotide sequences were detected in 17 pools of Culex and two pools of Aedes mosquitoes, respectively, among the 818 pools of non-engorged females analyzed. To the best of our knowledge, this is the first report of CxFV and AEFV in the city of São Paulo and Latin America, respectively. Both viruses are insect- specific flaviviruses, a group known to replicate only in mosquito cells and induce a cytopathic effect in some situations. Hence, our data suggests that CxFV and AEFV are present in Culex and Aedes mosquitoes, respectively, in parks in the city of São Paulo. Even though Flavivirus species of medical importance were not

  9. Differential effect of human ivermectin treatment on blood feeding Anopheles gambiae and Culex quinquefasciatus

    DEFF Research Database (Denmark)

    Derua, Yahya A.; Kisinza, William N.; Simonsen, Paul Erik

    2015-01-01

    BACKGROUND: Widespread and large scale use of ivermectin in humans and domestic animals can have unexpected effects on non-target organisms. As a search for a possible explanation for an observed longitudinal decline in density of anopheline vector mosquitoes, but not in Culex quinquefasciatus...... to receive either ivermectin or placebo. Twenty four hours after treatment, one volunteer from each group was concurrently exposed to 50 laboratory reared An. gambiae on one arm and 50 laboratory reared Cx. quinquefasciatus on the other arm for 15-30 minutes. Engorged mosquitoes were maintained on 10...

  10. Larvicidal and repellent properties of some essential oils against Culex tritaeniorhynchus Giles and Anopheles subpictus Grassi (Diptera: Culicidae).

    Science.gov (United States)

    Govindarajan, Marimuthu

    2011-02-01

    To investigate the larvicidal and repellent properties of essential oils from various parts of four plant species Cymbopogan citrates, Cinnamomum zeylanicum, Rosmarinus officinalis and Zingiber officinale against Culex tritaeniorhynchus (Cx. tritaeniorhynchus) and Anopheles subpictus (An. subpictus). Essential oils were obtained by hydro-distillation method. The mosquitoes were reared in the vector control laboratory and twenty five late third instar larvae of Cx. tritaeniorhynchus and An. subpictus were exposed to based on the wide range and narrow range test, essential oil tested at various concentrations ranging from 25 to 250 ppm. The larval mortality was observed after 24 h under the laboratory conditions. The repellent efficacy was determined against two mosquito species at three concentrations viz., 1.0, 2.5 and 5.0 mg/cm(2) under laboratory conditions. Results showed all the four plant essential oil produced significant larval mortality against two mosquito species. However, the highest larvicidal activity was observed in the essential oil from Zingiber officinale against Cx. tritaeniorhynchus and An. subpictus with the LC(50) and LC(90) values as 98.83, 57.98 ppm and 186.55, 104.23 ppm, respectively. All the four essential oil shows significant repellency against Cx. tritaeniorhynchus than An. subpictus. Among four essential oil tested the highest repellency was observed in Zingiber officinale, a higher concentration of 5.0 mg/cm(2) provided 100% protection up to 150 and 180 min against Cx. tritaeniorhynchus and An. subpictus, respectively. In this work, it can be concluded that four essential oils which were distilled from Cymbopogan citrates, Cinnamomum zeylanicum, Rosmarinus officinalis and Zingiber officinale showed promising larvicidal and repellent agent against Cx. tritaeniorhynchus and An. subpictus. Copyright © 2011 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  11. Influence of some plant extracts on the ovi-position behavior of Aedes fluviatilis and Culex quinquifasciatus

    Directory of Open Access Journals (Sweden)

    Abdulhakim A. El Maghrbi

    2014-06-01

    Full Text Available Alcoholic/acetone extracts of nine species of plants (Allium tuberosum, Apium leptophylum, Carica papaya, Cymbopogon citratus, Euphorbia cotinofolia, Melia azedarach, Ocimum canum, Ricinus communis and Tagetes erecta were tested in respect to their influence on the ovi-position behavior of the mosquito, Aedes fluviatilis and Culex quinquifasciatus in concentrations of 100, 10 and 1 mg/L. Three days after mosquito females had fed on blood of anesthetized mice and pigeon respectively, experimental and control dishes were placed into cages for 24 h then number of eggs laid in each dish was counted. Alcoholic/acetone extracts of C. papaya, C. citratus and T. erecta at 100 mg/L; E. cotinofolia and O. canum at 100 and 10 mg/L were proved to be repulsive for ovi-position of Ae. fluviatilis. On the other hand, acetone extracts of A. tuberosum and M. azederach at 100 and 10 mg/L; A. leptophyllum, O. canum, E. cotinofolia and R. communis at 100 mg/L produced same effect on ovi-position behavior of Ae. fluviatilis. Alcoholic extracts E. cotinofolia, R. communis (100 mg/L and M. azedarach (100 and 10 mg/L were attractive to Cx. quinquifasciatus. Five acetone extracts (A. tuberosum, A. leptophylum, C. papaya, C. Citrates and M. azedarach were repulsive for ovi-position at 100 mg/L. Acetone extract of A. tuberosum and M. azedarach at 10 and 1 mg/L and C. citratus at 10 mg/L maintained the same properties. Our results concluded that each plant extract has the potential to control ovi-position behavior of mosquito. The differences in obtained responses necessitate the adoption of deeper research to isolate the active principle of such plants for potential use in mosquito control program.

  12. Larvicidal efficacy of various formulations of Bacillus sphaericus against the resistant strain of Culex quinquefasciatus (Diptera: Culicidae) from southern India.

    Science.gov (United States)

    Subbiah, P; Ramesh, N; Sundaravadivelu, K; Samuel, P; Tyagi, B K

    2009-04-01

    Use of Bacillus sphaericus Neide (Bs) as potential biolarvicide in developing countries is limited due to development of resistance by target mosquitoes. Efforts are taken to look for appropriate formulations or combination of Bs to prevent or delay resistance problem. Here, we report the efficacy of a formulated Bs product to kill Bs resistant Culex quinquefasciatus Say larvae. The laboratory reared resistance colony was maintained by subjecting selection pressure with Bs (2362) toxin. Bioassays were conducted with lyophilized, standard formulated and Bs formulated by us (all belong to strain 2362, serotype H5a5b) against Bs resistant and susceptible colonies. The Bs resistant larvae showed a high level of resistance against lyophilized toxin with resistance ratio (RR) of 8375.2, 1055.6 and 11422.3 folds at LC(50), LC(90) and LC(95) levels, respectively, when compared with Bs susceptible larvae. With formulation of standard powder, the RR between Bs resistant and susceptible larvae were 1.01, 1.13 and 1.19 folds only at LC(50), LC(90) and LC(95) levels, respectively. This observation was comparable with our formulation prepared by a ground mixture of lyophilized Bs and a placebo (plaster of Paris). It is evident from our study, that the placebo present in our Bs 2362 formulation was responsible for increasing the efficacy of Bs lyophilized toxin against resistant larvae. The putative mechanism behind this toxicity phenomenon remains to be investigated to evolve new mosquito control strategies. A cross resistance to indigenous strain of Bs B42 (H5a5b) against Bs resistant larvae was also reported in this study.

  13. Septic tanks as larval habitats for the mosquitoes Aedes aegypti and Culex quinquefasciatus in Playa-Playita, Puerto Rico.

    Science.gov (United States)

    Burke, R; Barrera, R; Lewis, M; Kluchinsky, T; Claborn, D

    2010-06-01

    Adult Aedes aegypti (Linnaeus) (Diptera: Culicidae) were previously recovered from emergence traps on septic tanks in southeastern Puerto Rico. In this study we quantified immature mosquito abundance and its relationship with structural variables of the septic tanks and chemical properties of the water containing raw sewage. A miniaturized floating funnel trap was used to sample 89 septic tanks for larvae in the Puerto Rican community of Playa-Playita. Aedes aegypti larvae were recovered from 18% of the sampled tanks (10.3 larvae per septic tank per day). Larval presence was positively associated with cracking of the septic tank walls and uncovered access ports. Larval abundance was positively associated with cracking of the septic tank walls and larger tank surface areas, and inversely associated with the total dissolved solids (TDS). Culex quinquefasciatus (Say) larvae were also recovered from 74% of the septic tanks (129.6 larvae per septic tank per day). Larval presence was negatively associated with TDS in the water and larval abundance was positively associated with cracking of the septic tank walls. A screened, plastic emergence trap was used to sample 93 septic tanks within the community for Ae. aegypti and Cx. quinquefasciatus adults. Aedes aegypti adults were recovered from 49% of the sampled tanks (8.7 adults per septic tank per day) and Cx. quinquefasciatus adults were recovered from 97% of the sampled tanks (155.5 adults per septic tank per day). Aedes aegypti adult presence was positively associated with cracking, uncapped openings and septic water pH. The Ae. aegypti adult counts were positively associated with cracking and inversely associated with TDS and conductivity. This study marks the first published record of the recovery of Ae. aegypti larvae from holding tanks containing raw sewage in the Caribbean region. Our study indicates that Ae. aegypti larvae are present in sewage water and that septic tanks have at least the potential to maintain

  14. Comparative efficacies of permethrin-, deltamethrin- and alpha-cypermethrin-treated nets, against Anopheles arabiensis and Culex quinquefasciatus in northern Tanzania.

    Science.gov (United States)

    Mosha, F W; Lyimo, I N; Oxborough, R M; Matowo, J; Malima, R; Feston, E; Mndeme, R; Tenu, F; Kulkarni, M; Maxwell, C A; Magesa, S M; Rowland, M W

    2008-06-01

    Mosquito nets treated with permethrin, deltamethrin or alpha-cypermethrin at 25 mg/m(2) were evaluated in experimental huts in an area of rice irrigation near Moshi, in northern Tanzania. The nets were deliberately holed to resemble worn nets. The nets treated with permethrin offered the highest personal protection against Anopheles arabiensis (61.6% reduction in fed mosquitoes) and Culex quinquefasciatus (25.0%). Deltamethrin and alpha-cypermethrin provided lower personal protection against An. arabiensis (46.4% and 45.6%, respectively) and no such protection against Cx. quinquefasciatus. Permethrin performed poorly in terms of mosquito mortality, however, killing only 15.2% of the An. arabiensis and 9.2% of the Cx. quinquefasciatus exposed to the nets treated with this pyrethroid (after correcting for control mortality). The alpha-cypermethrin and deltamethrin performed marginally better, with respective mortalities of 32.8% and 33.0% for An. arabiensis and 19.4% and 18.9% for Cx quinquefasciatus. The poor killing effect of permethrin was confirmed in a second trial where a commercial, long-lasting insecticidal net based on this pyrethroid (Olyset) produced low mortalities in both An. arabiensis (11.8%) and Cx. quinquefasciatus (3.6%). Anopheles arabiensis survivors collected from the verandahs of the experimental huts and tested on 0.75%-permethrin and 0.05%-deltamethrin papers, in World Health Organization susceptibility kits, showed mortalities of 96% and 100%, respectively. The continued use of permethrin-treated nets is recommended for personal protection against An. arabiensis. In control programmes that aim to interrupt transmission of pathogens by mosquitoes and/or manage pyrethroid resistance in such vectors, a combination of a pyrethroid and another insecticide with greater killing effect should be considered.

  15. Ecology of potential West Nile virus vectors in southeastern Louisiana: enzootic transmission in the relative absence of Culex quinquefasciatus

    Science.gov (United States)

    Godsey, Marvin S.; King, Raymond J.; Burkhalter, Kristen; Delorey, Mark; Colton, Leah; Charnetzky, Dawn; Sutherland, Genevieve; Ezenwa, Vanessa O.; Wilson, Lawrence A.; Coffey, Michelle; Milheim, Lesley E.; Taylor, Viki G.; Palmisano, Charles; Wesson, Dawn M.; Guptill, Stephen C.

    2013-01-01

    A study of West Nile virus (WNV) ecology was conducted in St. Tammany Parish, Louisiana, from 2002 to 2004. Mosquitoes were collected weekly throughout the year using Centers for Disease Control and Prevention (CDC) light traps placed at 1.5 and 6 m above the ground and gravid traps. A total of 379,466 mosquitoes was collected. WNV was identified in 32 pools of mosquitoes comprising four species; 23 positive pools were from Culex nigripalpus collected during 2003. Significantly more positive pools were obtained from Cx. nigripalpus collected in traps placed at 6 m than 1.5 m that year, but abundance did not differ by trap height. In contrast, Cx. nigripalpus abundance was significantly greater in traps placed at 6 m in 2002 and 2004. Annual temporal variation in Cx. nigripalpus peak seasonal abundance has important implications for WNV transmission in Louisiana. One WNV-positive pool, from Cx. erraticus, was collected during the winter of 2004, showing year-round transmission. The potential roles of additional mosquito species in WNV transmission in southeastern Louisiana are discussed. Disclaimer: The opinions expressed in this article are the opinions of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention. This article has been peer reviewed and approved for publication consistent with U.S. Geological Survey Fundamental Science Practices (http//pubs.usgs.gov/circ/1367/). Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

  16. Evaluation of some aromatic plant extracts for mosquito larvicidal potential against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi.

    Science.gov (United States)

    Jayaraman, M; Senthilkumar, A; Venkatesalu, V

    2015-04-01

    In the present investigation, larvicidal potential of hexane, choloroform, ethyl acetate, acetone, and methanol extracts of seven aromatic plants, viz., Blumea mollis, Chloroxylon swietenia, Clausena anisata, Feronia limnonia, Lantana camera, Plectranthus amboinicus, and Tagetes erecta were screened against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. The larval mortality was observed after 12 and 24 h of exposure period. The results revealed that all the extracts showed varied levels of larvicidal activity against the mosquito species tested. However, the ethyl acetate extract of Chloroxylon swietenia showed the remarkable larvicidal activity against C. quinquefasciatus, Ae. aegypti, and An. stephensi. After 12 h of exposure period, the larvicidal activity was LC50 = 194.22 and LC90 = 458.83 ppm (C. quinquefasciatus), LC50 = 173.04 and LC90 = 442.73 ppm (Ae. aegypti), and LC50 = 167.28 and LC90 = 433.07 ppm (An. stephensi), and the larvicidal activity after 24-h exposure period was LC50 = 94.12 and LC90 = 249.83 ppm (C. quinquefasciatus), LC50 = 80.58 and LC90 = 200.96 ppm (Ae. aegypti), and LC50 = 76.24 and LC90 = 194.51 ppm (An. stephensi). The larvicidal potential of other plant extracts were in order of ethyl acetate extract of Clausena anisata > methanol extract of P. amboinicus > acetone extract of F. limonia > methanol extract of T. erecta > methanol extract of B. mollis > and methanol extract of L. camera. The results of the present study offer a possible way for further investigations to find out the active molecule responsible for the activity.

  17. Seasonal abundance & role of predominant Japanese encephalitis vectors Culex tritaeniorhynchus & Cx. gelidus Theobald in Cuddalore district, Tamil Nadu

    Science.gov (United States)

    Ramesh, D.; Muniaraj, M.; Samuel, P. Philip; Thenmozhi, V.; Venkatesh, A.; Nagaraj, J.; Tyagi, B.K.

    2015-01-01

    Background & objectives: Japanese encephalitis (JE) is the leading cause of viral encephalitis in Asia. The first major JE outbreak occurred in 1978 and since 1981 several outbreaks had been reported in the Cuddalore district (erstwhile South Arcot), Tamil Nadu, India. Entomological monitoring was carried out during January 2010 - March 2013, to determine the seasonal abundance and transmission dynamics of the vectors of JE virus, with emphasis on the role of Culex tritaeniorhynchus and Cx. gelidus. Methods: Mosquito collections were carried out fortnightly during dusk hours in three villages viz. Soundara Solapuram, Pennadam, Erappavur of Cuddalore district. Mosquitoes were collected during dusk for a period of one hour in and around the cattle sheds using oral aspirator and torch light. The collected mosquitoes were later identified and pooled to detect JE virus (JEV) infection by enzyme linked immunosorbent assay (ELISA). Results: A total of 46,343 mosquitoes comprising of 25 species and six genera were collected. Species composition included viz, Cx. tritaeniorhynchus (46.26%), Cx. gelidus (43.12%) and other species (10.62%). A total of 17,678 specimens (403 pools) of Cx. gelidus and 14,358 specimens (309 pools) of Cx. tritaeniorhynchus were tested, of which 12 pools of Cx. gelidus and 14 pools of Cx. tritaeniorhynchus were positive for JE virus antigen. The climatic factors were negatively correlated with minimum infection rate (MIR) for both the species, except mean temperature (P<0.05) for Cx. gelidus. Interpretation & conclusions: High abundance of Cx. tritaeniorhynchus and Cx. gelidus was observed compared to other mosquito species in the study area. Detection of JEV antigen in the two species confirmed the maintenance of virus. Appropriate vector control measures need to be taken to reduce the vector abundance. PMID:26905238

  18. Point mutations associated with organophosphate and carbamate resistance in Chinese strains of Culex pipiens quinquefasciatus (Diptera: Culicidae.

    Directory of Open Access Journals (Sweden)

    Minghui Zhao

    Full Text Available Acetylcholinesterase resistance has been well documented in many insects, including several mosquito species. We tested the resistance of five wild, Chinese strains of the mosquito Culex pipiens quinquefasciatus to two kinds of pesticides, dichlorvos and propoxur. An acetylcholinesterase gene (ace1 was cloned and sequenced from a pooled sample of mosquitoes from these five strains and the amino acids of five positions were found to vary (V185M, G247S, A328S, A391T, and T682A. Analysis of the correlation between mutation frequencies and resistance levels (LC50 suggests that two point mutations, G247S (r2 = 0.732, P = 0.065 and A328S (r2 = 0.891, P = 0.016, are associated with resistance to propoxur but not to dichlorvos. Although the V185M mutation was not associated with either dichlorvos or propoxur resistance, its RS genotype frequency was correlated with propoxur resistance (r2 = 0.815, P = 0.036. And the HWE test showed the A328S mutation is linked with V185M, also with G247S mutation. This suggested that these three mutations may contribute synergistically to propoxur resistance. The T682A mutation was negatively correlated with propoxur (r2 = 0.788, P = 0.045 resistance. Knowledge of these mutations may help design strategies for managing pesticide resistance in wild mosquito populations.

  19. Point mutations associated with organophosphate and carbamate resistance in Chinese strains of Culex pipiens quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Zhao, Minghui; Dong, Yande; Ran, Xin; Wu, Zhiming; Guo, Xiaoxia; Zhang, Yingmei; Xing, Dan; Yan, Ting; Wang, Gang; Zhu, Xiaojuan; Zhang, Hengduan; Li, Chunxiao; Zhao, Tongyan

    2014-01-01

    Acetylcholinesterase resistance has been well documented in many insects, including several mosquito species. We tested the resistance of five wild, Chinese strains of the mosquito Culex pipiens quinquefasciatus to two kinds of pesticides, dichlorvos and propoxur. An acetylcholinesterase gene (ace1) was cloned and sequenced from a pooled sample of mosquitoes from these five strains and the amino acids of five positions were found to vary (V185M, G247S, A328S, A391T, and T682A). Analysis of the correlation between mutation frequencies and resistance levels (LC50) suggests that two point mutations, G247S (r2 = 0.732, P = 0.065) and A328S (r2 = 0.891, P = 0.016), are associated with resistance to propoxur but not to dichlorvos. Although the V185M mutation was not associated with either dichlorvos or propoxur resistance, its RS genotype frequency was correlated with propoxur resistance (r2 = 0.815, P = 0.036). And the HWE test showed the A328S mutation is linked with V185M, also with G247S mutation. This suggested that these three mutations may contribute synergistically to propoxur resistance. The T682A mutation was negatively correlated with propoxur (r2 = 0.788, P = 0.045) resistance. Knowledge of these mutations may help design strategies for managing pesticide resistance in wild mosquito populations.

  20. Larvicidal activity of essential oil of Peumus boldus Molina and its ascaridole-enriched fraction against Culex quinquefasciatus.

    Science.gov (United States)

    de Castro, Débora Silva Borges; da Silva, Denise Brentan; Tibúrcio, Jacqueline Domingues; Sobral, Marcos Eduardo Guerra; Ferraz, Vany; Taranto, Alex Gutterres; Serrão, José Eduardo; de Siqueira, João Máximo; Alves, Stênio Nunes

    2016-12-01

    Culex quinquefasciatus (Say, 1823), known as the domestic mosquito, is a common and abundant species throughout the world, and a cosmopolitan species. The adults of this mosquito are important in terms of public and animal health since they display adaptability to different hosts. In humans, they are responsible for the transmission of various diseases. One manner of control of this vector is the use of insecticidal or larvicidal products, which may have the drawback of toxicity to mammals and can be harmful to the environment. The present work evaluated the larvicidal potential of the essential oil (EO) and ascaridole-enriched fraction (EF4-5) obtained from the leaves of Peumus boldus Molina (boldo). The EO, obtained by steam distillation, was analyzed by GC/MS and fractionated on silica gel. EO and EF4-5, containing 31.4% and 89.5% ascaridole, respectively, were evaluated against C. quinquefasciatus at concentrations of 100, 50 and 25 μg/ml on the third and fourth instars. They showed lethal concentrations (LC50) of 82.14 and 41.85 μg/ml, respectively. Larvae treated with the EF4-5 showed morphological changes in the midgut, with cells possessing a cytoplasm that contained small vacuole-like structures, as well as a nucleus with decondensed chromatin and a cell apex with a short brush border. The cells of the fat body showed larger protein granules, which were acidophilic relative to the larvae of the control group. Moreover, the enriched fraction at a dose of 50 μg/ml showed a residual larvicidal effect according to exposure time on C. quinquefasciatus. This residual effect deserves consideration, since a long-term larvicidal product may be a useful tool for vector control. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Mukia maderaspatana (Cucurbitaceae) extract-mediated synthesis of silver nanoparticles to control Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Chitra, Govindaraj; Balasubramani, Govindasamy; Ramkumar, Rajendiran; Sowmiya, Rajamani; Perumal, Pachiappan

    2015-04-01

    Mosquitoes and mosquito-borne diseases are prone to raise health and economic impacts. Synthetic insecticide-based interventions are indeed in situations of epidemic outbreak and sudden increases of adult mosquitoes. Nanoparticles are being used in many commercial applications and were found that aqueous silver ions can be reduced by an aqueous extract of plant parts to generate extremely stable silver nanoparticles in water. Based on this, silver nanoparticles (SNPs) were synthesized using leaf aqueous extract (LAE) of Mukia maderaspatana. Further, the synthesized SNPs were characterized by UV-visible spectrum, which indicated a strong plasmon resonance at 427 nm. X-ray diffraction (XRD) analysis revealed the average crystalline size of the synthesized SNPs was approximately 64 nm by Debye-Scherrer formulae. Fourier transform infrared (FTIR) spectroscopy analysis revealed the presence of different functional groups like amines, halides, alkanes, alkynes, amides, and esters with respective stretches, which are responsible for the bio-reduction of silver ions. Field emission scanning electron microscopy (FESEM) depicted the spherical morphology of SNPs with size range of 13-34 nm. The larvicidal activity of LAE and SNPs exhibited an effective mortality to Aedes aegypti and Culex quinquefasciatus. The lethal concentration (LC50; LC90) of LAE and SNPs were found to be 0.506; 1.082, 0.392; 0.870 ppm and 0.211; 0.703, 0.094; 0.482 ppm, respectively on A. aegypti and C. quinquefasciatus. Thus, the synthesized SNPs have shown preponderant larvicidal activity, but further studies are needed to formulate the potential larvicidal agents.

  2. Plasmodium relictum (lineages pSGS1 and pGRW11): complete synchronous sporogony in mosquitoes Culex pipiens pipiens.

    Science.gov (United States)

    Kazlauskienė, Rita; Bernotienė, Rasa; Palinauskas, Vaidas; Iezhova, Tatjana A; Valkiūnas, Gediminas

    2013-04-01

    Plasmodium relictum is a widespread invasive agent of avian malaria, responsible for acute, chronic and debilitating diseases in many species of birds. Recent PCR-based studies revealed astonishing genetic diversity of avian malaria parasites (genus Plasmodium), with numerous genetic lineages deposited in GenBank. Many studies addressed distribution and evolutionary relationships of avian Plasmodium lineages, but information about patterns of development of different lineages in mosquito vectors remains insufficient. Here we present data on sporogonic development of 2 widespread mitochondrial cytochrome b lineages (cyt b) of P. relictum (pSGS1 and pGRW11) in mosquito Culex pipiens pipiens. Genetic distance between these lineages is 0.2%; they fall in a well-supported clade in the phylogenetic tree. Three P. relictum strains were isolated from common crossbill (Loxia curvirostra, lineage pSGS1), domestic canary (Serinus canaria domestica, pSGS1) and house sparrow (Passer domesticus, pGRW11). These strains were multiplied in domestic canaries and used as donors of malarial gametocytes to infect C. p. pipiens. Mosquitoes were allowed to take blood meal on infected canaries and then dissected on intervals to study development of sporogonic stages. All 3 strains developed synchronously and completed sporogony in this vector, with infective sporozoites reported in the salivary glands on the day 14 after infection. Ookinetes, oocysts and sporozoites of all strains were indistinguishable morphologically. This study shows that patterns of sporogonic development of the closely related lineages pSGS1 and pGRW11 and different strains of the lineage pSGS1 of P. relictum are similar indicating that phylogenetic trees based on the cyt b gene likely can be used for predicting sporogonic development of genetically similar avian malaria lineages in mosquito vectors. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Chemical constituents and larvicidal potential of Feronia limonia leaf essential oil against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus.

    Science.gov (United States)

    Senthilkumar, A; Jayaraman, M; Venkatesalu, V

    2013-03-01

    In the present investigation, the leaf essential oil of Feronia limonia was evaluated for chemical constituents and mosquito larvicidal activity against the larvae of Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. GC and GC-MS analyses revealed that the essential oil contain 51 compounds. Estragole (34.69 %) and β-pinene(23.59 %) were identified as the major constituents followed by methyl (Z)-caryophyllene (11.05 %), eugenol (6.50 %), linalool (3.97 %), phytol (3.27 %), sabinene (2.41 %) and limonene (2.27 %). Larval mortality was observed after 12 and 24 h of exposure period. The oil showed remarkable larvicidal activity against A. stephensi (LC(50) = 38.93 and LC(90) = 108.64 ppm (after 12 h); LC(50) = 15.03 and LC(90) = 36.69 ppm (after 24 h)), A. aegypti (LC(50) = 37.60 and LC(90) = 104.69 ppm (after 12 h); LC(50) = 11.59 and LC(90) = 42.95 ppm (after 24 h)) and C. quinquefasciatus (LC(50) = 52.08 and LC(90) = 124.33 ppm (after 12 h); LC(50) = 22.49 and LC(90) = 60.90 ppm (after 24 h)). Based on the results, the essential oil of F. limonia can be considered as a new source of larvicide for the control of vector mosquitoes.

  4. Seasonal abundance & role of predominant Japanese encephalitis vectors Culex tritaeniorhynchus & Cx. gelidus Theobald in Cuddalore district, Tamil Nadu.

    Science.gov (United States)

    Ramesh, D; Muniaraj, M; Samuel, P Philip; Thenmozhi, V; Venkatesh, A; Nagaraj, J; Tyagi, B K

    2015-12-01

    Japanese encephalitis (JE) is the leading cause of viral encephalitis in Asia. The first major JE outbreak occurred in 1978 and since 1981 several outbreaks had been reported in the Cuddalore district (erstwhile South Arcot), Tamil Nadu, India. Entomological monitoring was carried out during January 2010 - March 2013, to determine the seasonal abundance and transmission dynamics of the vectors of JE virus, with emphasis on the role of Culex tritaeniorhynchus and Cx. gelidus. Mosquito collections were carried out fortnightly during dusk hours in three villages viz. Soundara Solapuram, Pennadam, Erappavur of Cuddalore district. Mosquitoes were collected during dusk for a period of one hour in and around the cattle sheds using oral aspirator and torch light. The collected mosquitoes were later identified and pooled to detect JE virus (JEV) infection by enzyme linked immunosorbent assay (ELISA). A total of 46,343 mosquitoes comprising of 25 species and six genera were collected. Species composition included viz, Cx. tritaeniorhynchus (46.26%), Cx. gelidus (43.12%) and other species (10.62%). A total of 17,678 specimens (403 pools) of Cx. gelidus and 14,358 specimens (309 pools) of Cx. tritaeniorhynchus were tested, of which 12 pools of Cx. gelidus and 14 pools of Cx. tritaeniorhynchus were positive for JE virus antigen. The climatic factors were negatively correlated with minimum infection rate (MIR) for both the species, except mean temperature (P<0.05) for Cx. gelidus. High abundance of Cx. tritaeniorhynchus and Cx. gelidus was observed compared to other mosquito species in the study area. Detection of JEV antigen in the two species confirmed the maintenance of virus. Appropriate vector control measures need to be taken to reduce the vector abundance.

  5. Larvicidal Activities of Indigenous Bacillus thuringiensis Isolates and Nematode Symbiotic Bacterial Toxins against the Mosquito Vector, Culex pipiens (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Ashraf M Ahmed

    2017-06-01

    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.

  6. Evaluation of water and ethanol extracts of Schinus molle Linn. against immature Culex quinquefasciatus Say (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Kidanemariam Girmay

    2014-06-01

    Full Text Available Objective: To evaluate larvicidal and pupicidal activities of aqueous and ethanol extract of different parts of Schinus molle against filarial vector, Culex quinquefasciatus (Cx. quinquefasciatus in the laboratory. Methods: The mortality rate of third, fourth instar larvae and pupal stages were tested at 20, 40, 60, 80 and 100 mg/L of plant extract using WHO standard protocol with modifications. The mortality rate was recorded continuously for 24, 48 and 72 h post exposure period and percentage mortality was calculated. Results: Maximum percentage mortality of third instar was 83.3% in ethanol extract of mature fruit at 100 mg/L after 24 h exposure period. After 48 h exposure period, 93.3% percentage mortality was recorded in ethanol extract of immature fruit at 100 mg/L. After 72 h exposure period, 100% mortality was recorded in water extract of leaf at 100 mg/L. In fourth instar larvae, maximum percentage mortality of 63.3% was recorded in water extract of mature fruit and ethanol extract of immature and mature fruit at 100 mg/L after 24 h exposure period. After 48 h exposure period 86.6% mortality was recorded in ethanol extract of mature fruit at 100 mg/L. After 72 h exposure period, 93.3% mortality was recorded in ethanol extract of mature fruit at 100 mg/L. In general immature Cx. quinquefasciatus, percentage mortality was increased with increase in exposure time and concentration of the plant extracts tested. Conclusions: From this laboratory study, Schinus molle plant parts were proved to have larvicidal and pupicidal activity against immature Cx. quinquefasciatus.

  7. Evaluation of water and ethanol extracts of Schinus molle Linn. against immature Culex quinquefasciatus Say (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Kidanemariam Girmay; Bemnet Fikre; Atsede Asmelash; Biskut Getachew; Emebet Tekle; Nagappan Raja

    2014-01-01

    Objective: To evaluate larvicidal and pupicidal activities of aqueous and ethanol extract of different parts of Schinus molle against filarial vector, Culex quinquefasciatus (Cx. quinquefasciatus) in the laboratory. Methods:The mortality rate of third, fourth instar larvae and pupal stages were tested at 20, 40, 60, 80 and 100 mg/L of plant extract using WHO standard protocol with modifications. The mortality rate was recorded continuously for 24, 48 and 72 h post exposure period and percentage mortality was calculated. Results: Maximum percentage mortality of third instar was 83.3%in ethanol extract of mature fruit at 100 mg/L after 24 h exposure period. After 48 h exposure period, 93.3%percentage mortality was recorded in ethanol extract of immature fruit at 100 mg/L. After 72 h exposure period, 100%mortality was recorded in water extract of leaf at 100 mg/L. In fourth instar larvae, maximum percentage mortality of 63.3%was recorded in water extract of mature fruit and ethanol extract of immature and mature fruit at 100 mg/L after 24 h exposure period. After 48 h exposure period 86.6%mortality was recorded in ethanol extract of mature fruit at 100 mg/L. After 72 h exposure period, 93.3%mortality was recorded in ethanol extract of mature fruit at 100 mg/L. In general immature Cx. quinquefasciatus, percentage mortality was increased with increase in exposure time and concentration of the plant extracts tested. Conclusions: From this laboratory study, Schinus molle plant parts were proved to have larvicidal and pupicidal activity against immature Cx. quinquefasciatus.

  8. Mosquito larvicidal activity of some common spices and vegetable waste onCulex quinquefasciatus andAnopheles stephensi

    Institute of Scientific and Technical Information of China (English)

    Someshwar Singha; Goutam Chandra

    2011-01-01

    Objective:To investigate the larvicidal activities of crude and chloroform: methanol (1:1 v/v) extracts of some common spices (Cuminum cyminum, Allium sativum, Zingiber offinale, Curcuma longa) and vegetable waste (Solanum tuberosum germinated tuber) againstAnopheles stephensiandCulex quinquefasciatus mosquito larvae.Methods:Larval mortality of above mosquito species were observed after 24, 48 and72 h of exposure to five concentrations of aqueous extract (0.1%, 0.2%, 0.3%, 0.4% and0.5%) and four concentrations (25, 50, 75 ppm) of chloroform: methanol (1:1 v/v) extract. The lethal concentration of individual spices or vegetable waste was determined by log-probit analysis (at95%confidence level) and effect of crude and chloroform: methanol (1:1 v/v) extracts were recorded on non target organisms.Results:Relative mortality rate of both larval mosquito species were recorded in the following sequences:Cuminum cyminum>Allium sativum>Zingiber offinale, Curcuma longa > Solanum tuberosum germinated tuber for crude extract, and efficacy of chloroform: methanol (1:1 v/v) extract were as follows:Curcuma longa > Zingiber offinale > Solanum tuberosum germinated tuber >Cuminum cyminum>Allium sativum.Conclusions: Crude and chloroform: methanol (1:1 v/v) extract of Cuminum cyminum, Allium sativum, Zingiber offinale, Curcuma longa andSolanum tuberosum germinated tuber can be recommended effectively in mosquito control programmes at very low concentrations. No mortality and other abnormalities were noticed on non target organisms and further studies are needed to investigate the chemical structure of active principal which are responsible for larvicidal activity.

  9. “BIRD BITING” MOSQUITOES AND HUMAN DISEASE: A REVIEW OF THE ROLE OF CULEX PIPIENS COMPLEX MOSQUITOES IN EPIDEMIOLOGY

    Science.gov (United States)

    Farajollahi, Ary; Fonseca, Dina M.; Kramer, Laura D.; Kilpatrick, A. Marm

    2011-01-01

    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 it feeds 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 Cx. pipiens pipiens with two forms, pipiens and molestus, Cx. pipiens pallens, Cx. quinquefasciatus, Cx. australicus, and Cx. globocoxitus. While several members of the complex have limited geographic distributions, Cx. pipiens pipiens 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. PMID:21875691

  10. Expression Profiles and RNAi Silencing of Inhibitor of Apoptosis Transcripts in Aedes, Anopheles, and Culex Mosquitoes (Diptera: Culicidae).

    Science.gov (United States)

    Puglise, Jason M; Estep, Alden S; Becnel, James J

    2016-03-01

    Effective mosquito control is vital to curtail the devastating health effects of many vectored diseases. RNA interference (RNAi)-mediated control of mosquitoes is an attractive alternative to conventional chemical pesticides. Previous studies have suggested that transcripts for inhibitors of apoptosis (IAPs) may be good RNAi targets. To revisit and extend previous reports, we examined the expression of Aedes aegypti (L.) IAPs (AaeIAPs) 1, 2, 5, 6, 9, and a viral IAP-associated factor (vIAF) as well as Anopheles quadrimaculatus Say and Culex quinquefasciatus Say IAP1 homologs (AquIAP1 and CquIAP1) in adult females. Expression profiles of IAPs suggested that some older female mosquitoes had significantly higher IAP mRNA levels when compared to the youngest ones. Minor differences in expression of AaeIAPs were observed in mosquitoes that imbibed a bloodmeal, but the majority of the time points (up to 48 h) were not significantly different. Although in vitro experiments with the Ae. aegypti Aag-2 cell line demonstrated that the various AaeIAPs could be effectively knocked down within one day after dsRNA treatment, only Aag-2 cells treated with dsIAP1 displayed apoptotic morphology. Gene silencing and mortality were also evaluated after topical application and microinjection of the same dsRNAs into female Ae. aegypti. In contrast to previous reports, topical administration of dsRNA against AaeIAP1 did not yield a significant reduction in gene expression or increased mortality. Knockdown of IAP1 and other IAPs by microinjection did not result in significant mortality. In toto, our findings suggest that IAPs may not be suitable RNAi targets for controlling adult mosquito populations.