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Sample records for aegypti culex quinquefasciatus

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

    PubMed

    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.

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

    PubMed Central

    Sritabutra, Duangkamon; Soonwera, Mayura

    2013-01-01

    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×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.

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

    PubMed

    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. Stormwater Drains and Catch Basins as Sources for Production of Aedes aegypti and Culex quinquefasciatus

    PubMed Central

    Arana-Guardia, Roger; Baak-Baak, Carlos M.; Loroño-Pino, María Alba; Machain-Williams, Carlos; Beaty, Barry J.; Eisen, Lars; García-Rejón, Julián E.

    2014-01-01

    We present data showing that structures serving as drains and catch basins for stormwater are important sources for production of the mosquito arbovirus vectors Aedes aegypti and Culex quinquefasciatus in Mérida City, México. We examined 1,761 stormwater drains – located in 45 different neighborhoods spread across the city – over dry and wet seasons from March 2012–March 2013. Of the examined stormwater drains, 262 (14.9%) held water at the time they were examined and 123 yielded mosquito immatures. In total, we collected 64,560 immatures representing nine species. The most commonly encountered species were Cx. quinquefasciatus (n=39,269) and Ae. aegypti (n=23,313). Ae. aegypti and Cx. quinquefasciatus were collected during all 11 months when we found water-filled stormwater drains, and both were found in stormwater drains located throughout Mérida City. We also present data for associations between structural characteristics of stormwater drains or water-related characteristics and the abundance of mosquito immatures. In conclusion, stormwater drains produce massive numbers of Ae. aegypti and Cx. quinquefasciatus across Mérida City, both in the wet and dry seasons, and represent non-residential development sites that should be strongly considered for inclusion in the local mosquito surveillance and control program. PMID:24582840

  5. Stormwater drains and catch basins as sources for production of Aedes aegypti and Culex quinquefasciatus.

    PubMed

    Arana-Guardia, Roger; Baak-Baak, Carlos M; Loroño-Pino, María Alba; Machain-Williams, Carlos; Beaty, Barry J; Eisen, Lars; García-Rejón, Julián E

    2014-06-01

    We present data showing that structures serving as drains and catch basins for stormwater are important sources for production of the mosquito arbovirus vectors Aedes aegypti and Culex quinquefasciatus in Mérida City, México. We examined 1761 stormwater drains - located in 45 different neighborhoods spread across the city - over dry and wet seasons from March 2012 to March 2013. Of the examined stormwater drains, 262 (14.9%) held water at the time they were examined and 123 yielded mosquito immatures. In total, we collected 64,560 immatures representing nine species. The most commonly encountered species were Cx. quinquefasciatus (n=39,269) and Ae. aegypti (n=23,313). Ae. aegypti and Cx. quinquefasciatus were collected during all 11 months when we found water-filled stormwater drains, and both were found in stormwater drains located throughout Mérida City. We also present data for associations between structural characteristics of stormwater drains or water-related characteristics and the abundance of mosquito immatures. In conclusion, stormwater drains produce massive numbers of Ae. aegypti and Cx. quinquefasciatus across Mérida City, both in the wet and dry seasons, and represent non-residential development sites that should be strongly considered for inclusion in the local mosquito surveillance and control program.

  6. Field evaluations of disposable sticky lures for surveillance of Aedes aegypti (Stegomyia aegypti) and Culex quinquefasciatus in Jakarta.

    PubMed

    Kay, B H; Brown, M D; Siti, Z; Bangs, M J

    2013-09-01

    From December 1997 to April 1998, disposable sticky lures (1608 lure days) were trialled in homes in north Jakarta, Indonesia as surveillance tools for Aedes aegypti (Stegomyia aegypti) (Diptera: Culicidae) and Culex quinquefasciatus (Diptera: Culicidae), referenced to indoor resting adult collections (92 × 10 min). The lures collected 89.4% of the total of 1339 Ae. aegypti and 92.1% of the total of 1272 Cx. quinquefasciatus collected by all methods. Because there were no significant differences with respect to numbers collected in bedrooms, living rooms and kitchens, bedrooms were selected for subsequent trials for reasons of convenience. The main trials involved a replicated complete block design with L-lysine and sodium carbonate. Lures without attractant or with four different dilutions of L-lysine collected 3.4-8.5 times more Ae. aegypti and 4.2-8.1 times more Cx. quinquefasciatus than were collected by mouth aspirator. Lures with or without dilutions of sodium carbonate collected 2.7-5.0 times more Ae. aegypti and 1.8-4.2 times more Cx. quinquefasciatus than aspirator collections. The precision associated with catches of sticky lures was better than that for aspirator collections. Although olfactants generally improved the numbers of mosquitoes collected, the differences in catch between lures with and without attractants were usually non-significant. Any deficit in catch may be offset by increasing the surveillance period to ≥30 days to detect all four dengue serotypes from infected mosquitoes.

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

    PubMed

    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.

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

    PubMed

    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. PMID:25646797

  9. Insecticidal and Repellent Activity of Siparuna guianensis Aubl. (Negramina) against Aedes aegypti and Culex quinquefasciatus

    PubMed Central

    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. PMID:25646797

  10. Susceptibility of Aedes aegypti and Culex quinquefasciatus Larvae to gedunin-related limonoids.

    PubMed

    Gurulingappa, Hallur; Tare, Vrushali; Pawar, Pushpa; Tungikar, Vijay; Jorapur, Yogesh R; Madhavi, Sriram; Bhat, Sujata V

    2009-06-01

    The major non-azadirachtin limonoids such as gedunin (1), epoxyazadiradione (3), nimbocinol (4), and nimolicinol (5) from Azadirachta indica A. Juss ('neem') and their derivatives were evaluated for their toxic action against fourth instar larvae of Aedes aegypti L. and Culex quinquefasciatus Say. Gedunin exhibited 100% toxic action against both the mosquito larvae at 50 and 10 ppm. Epoxyazadiradione and epoxynimolicinol also showed significant toxicities (> or =50%) against larvae of both mosquito species at 50 ppm. These neem limonoids can have benefits in mosquito-control programs. PMID:19551731

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

    PubMed

    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.

  12. Mosquito larvicidal activity of seaweeds extracts against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus

    PubMed Central

    Ali, Mohamed Yacoob Syed; Ravikumar, Sundaram; Beula, Johanson Margaret

    2013-01-01

    Objective To identify the larvicidal activity of the seaweed extracts against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus Methods Seaweed extracts of Ulva lactuca, Caulerpa racemosa (C. racemosa), Sargassum microystum, Caulerpa scalpelliformis, Gracilaria corticata, Turbinaria decurrens, Turbinaria conoides and Caulerpa toxifolia were dissolved in DMSO to prepare a graded series of concentration. The test for the larvicidal effect of seaweeds against mosquitos larvae was conducted in accordance with the WHO standard method. Batches of 25 early 4th instar larvae of three mosquitoes were transferred to 250 mL enamel bowl containing 199 mL of distilled water and 1 mL of plant extracts (10-100 µg). Each experiment was conducted with triplicate with concurrent a control group. Results Among the seaweeds extract, C. racemosa showed toxicity against 4th instar larvae of Aedes aegypti, Culex quinquefasciatus, Anopheles stephensi with equivalent LC50 value (0.055 6±0.010 3) µg/mL, (0.067 5±0.136 0) µg/mL and (0.066 1±0.007 6) µg/mL, respectively. Conclusions The present study concluded that, the mosquito larvicidal property of C. racemosa might be the prospective alternative source to control the mosquitoes.

  13. Ovicidal and repellent activities of botanical extracts against Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi (Diptera: Culicidae)

    PubMed Central

    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 of Ervatamia 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. PMID:23569723

  14. Mosquito larvicidal properties of Orthisiphon thymiflorus (Roth) Sleesen. (Family: Labiatae) against mosquito vectors, Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: To determine the larvicidal activity of hexane, chloroform, ethyl acetate, acetone, and methanol extracts of Orthosiphon thymiflorus leaves against Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti. Methods: Larvicidal activity was determined in laboratory bioassays using var...

  15. Larvicidal and pupicidal activities of essential oils from Zingiberaceae plants against Aedes aegypti (Linn.) and Culex quinquefasciatus say mosquitoes.

    PubMed

    Phukerd, Ubol; Soonwera, Mayura

    2013-09-01

    We conducted this study to investigate the efficacy of herbal essential oils from 12 species of Zingiberaceae plants to determine their larvicidal and pupicidal activity against fourth instar larvae and pupae of Aedes aegypti and Culex quinquefasciatus mosquitoes. Probit analysis was used to analyze the data. Larval mortality was recorded at 1, 5, 10, 15, 30 and 60 minutes and 24 hours. Pupal mortality was recorded at 15 and 30 minutes and 1, 3, 6, 12, 24 and 48 hours. All the essential oils tested showed larvicidal activity. Zingiber cassumunar and Amomum biflorum oils proved to have the greatest activity against Ae. aegypti larvae with LT50 of 1.4 minutes and 100% mortality at 5 and 10 minutes, respectively. Boesenbergia rotunda, Curcuma zedoaria and Hedychium coronarium essential oils had activity against Cx. quinquefasciatus larvae with LT50 of 1.7 minutes and 100% mortality at 10 minutes, 5 minutes and 15 minutes, respectively. All the herbal essential oils tested resulted in 100% mortality against Ae. aegypti and Cx. quinquefasciatus larvae at 60 minutes and 30 minutes, respectively. Ae. aegypti and Cx. quinquefasciatus pupae were susceptible to Z. ottensii oil (LT50 of 0.2 hour) and Z. zerumbet oil (LT50 of 0.6 hour) and had pupicidal activity with 100% mortality at 6 and 3 hours, respectively. All the essential oils test had pupicidal activity against Ae. aegypti and Cx. quinquefasciatus by inducing 100% mortality at 48 hours. PMID:24437311

  16. Adulticidal and repellent properties of indigenous plant extracts against Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae).

    PubMed

    Govindarajan, Marimuthu; Sivakumar, Rajamohan

    2012-05-01

    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, chikunguniya fever, West Nile virus, and yellow fever. These diseases produce significant morbidity and mortality in humans and livestock around the world. The adulticidal and repellent activities of crude hexane, ethyl acetate, benzene, chloroform, and methanol extracts of leaf of Eclipta alba and Andrographis paniculata were assayed for their toxicity against two important vector mosquitoes, viz., Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae). The adult mortality was observed after 24 h of exposure. All extracts showed moderate adulticide effects; however, the highest adult mortality was found in methanol extract of A. paniculata against the adults of C. quinquefasciatus and A. aegypti with the LC(50) and LC(90) values were 149.81, 172.37 ppm and 288.12, 321.01 ppm, respectively. The results of the repellent activity of hexane, ethyl acetate, benzene, chloroform, and methanol extract of E. alba and A. paniculata plants at three different concentrations of 1.0, 2.5, and 5.0 mg/cm(2) were applied on skin of forearm 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 repellent activity is dependent on the strength of the plant extracts. These results suggest that the leaf solvent plant extracts have the potential to be used as an ideal ecofriendly approach for the control of mosquitoes. This is the first report on the mosquito adulticidal and repellent activities of the reported E. alba and A. paniculata plants.

  17. Efficacy of herbal essential oils as insecticide against Aedes aegypti (Linn.), Culex quinquefasciatus (Say) and Anopheles dirus (Peyton and Harrison).

    PubMed

    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. PMID:22299433

  18. Septic tanks as larval habitats for the mosquitoes Aedes aegypti and Culex quinquefasciatus in Playa-Playita, Puerto Rico.

    PubMed

    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

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

    PubMed

    Phukerd, Ubol; Soonwera, Mayura

    2014-09-01

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

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

    PubMed

    Phukerd, Ubol; Soonwera, Mayura

    2014-09-01

    Repellent activity of essential oils derived from 10 Thai native plants, belonging to three families were evaluated against female Aedes aegypti and Culex quinquefasciatus and to compare them with a commercial chemical repellents (DEET; N,N-diethyl-3-methylbenzamide 20% w/w; Sketolene Shield). Each test repellent was applied at 1, 5, and 10% concentrations for testing by arm in cage method. The results showed significant differences in repellency among the repellents by mosquito species. The protection time of the essential oils against Ae. aegypti ranged from 3 to 30 min. According to the Culex mosquito, it showed the protection time ranged from 3 to 260 min. 10 % Boesenbergia rotunda essential oil provided the best efficiency, in which protection time was 4.3 h as equal as DEET. The essential oils which exhibited protection time more than 2 h were those of 10% Zingiber zerumbet, Litsea petiolata, Curcuma zedoaria, and Zingiber cassumunar essential oils (3.1, 2.8, 2.6, and 2.3 h, respectively). The biting percentage ranged from 0.9 to 18.0% and 0.8 to 3.6% against Ae. aegypti and Cx. quinquefasciatus, respectively. The results revealed that the potential of essential oil extracted from B. rotunda, Z. zerumbet, L. petiolata, C. zedoaria, and Z. cassumunar had attributes of good repellent and deterred biting. We recommend the five essential oils for further study to develop as commercial repellents. PMID:25088471

  1. Insecticidal and repellent activity of Clausena dentata (Rutaceae) plant extracts against Aedes aegypti and Culex quinquefasciatus mosquitoes (Diptera: Culicidae).

    PubMed

    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.

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

    PubMed Central

    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 million (ppm), 125 ppm, 250 ppm, and 500 ppm—were prepared using acetone and tested for ovicidal and oviposition deterrent activities. One-way analysis of variance (ANOVA) was used to determine the significance of the treatments and means were separated by Tukey's test of comparison. Results Among the different extracts of the five plants screened, the hexane extract of L. acidissima recorded the highest ovicidal activity of 79.2% and 60% at 500 ppm concentration against the eggs of Cx. quinquefasciatus and Ae. aegypti, respectively. Similarly, the same hexane extract of L. acidissima showed 100% oviposition deterrent activity at all the tested concentrations against Cx. quinquefasciatus and Ae. aegypti adult females. Conclusion It is concluded that the hexane extract of L. acidissima could be used in an integrated mosquito management program. PMID:25737834

  3. Evaluation of some aromatic plant extracts for mosquito larvicidal potential against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi.

    PubMed

    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. PMID:25630696

  4. Evaluation of some aromatic plant extracts for mosquito larvicidal potential against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi.

    PubMed

    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.

  5. Behavioral responses of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus against various synthetic and natural repellent compounds.

    PubMed

    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.

  6. Behavioral responses of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus against various synthetic and natural repellent compounds.

    PubMed

    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. PMID:25424262

  7. Adulticidal and smoke toxicity of Cipadessa baccifera (Roth) plant extracts against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus.

    PubMed

    Ramkumar, Govindaraju; Karthi, Sengodan; Muthusamy, Ranganathan; Natarajan, Devarajan; Shivakumar, Muthugounder S

    2015-01-01

    Mosquito vectors are responsible for the transmission of parasitic and viral infections, including loss in commercial and labor outputs, particularly in developing countries with tropical and subtropical climates. The aim of the present study is to evaluate the adulticidal and smoke toxicity of Cipadessa baccifera (Roth) against three important mosquitoes vectors, Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae). 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 acetone extract against An. stephensi followed by Ae. aegypti and Cx. quinquefasciatus with the LD50 and LD90 values 16.021 (14.080-18.345), 29.095 (25.118-34.089); 23.581 (22.100-28.315), 38.636 (35.321-41.021); and 13.560 (9.479-17.391), 248.35 (203.47-344.43) mg/ml, respectively. No mortality was recorded in the control. Smoke toxicity was observed at 10-min interval for 40 min and the mortality data were recorded. Among the C. baccifera plant powder tested. Smoke toxicity results show that Cx. quinquefasciatus, An. stephensi, and Ae. aegypti shows 88.6 ± 1.8, 78.2 ± 0.5, and 77 ± 1, respectively. One hundred percent mortality was recorded in the commercial mosquito control. The present study shows that C. baccifera leaf powder can be used as an efficient toxicity against mosquitoes. These results suggest that the leaf extracts of C. baccifera have a potential to be used as an ideal eco-friendly approach for the control of mosquitoes. PMID:25320044

  8. Larvicidal activity of Morinda citrifolia L. (Noni) (Family: Rubiaceae) leaf extract against Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti.

    PubMed

    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

  9. Effect of triflumuron, a chitin synthesis inhibitor, on Aedes aegypti, Aedes albopictus and Culex quinquefasciatus under laboratory conditions

    PubMed Central

    2013-01-01

    Background Resistance to traditional insecticides represents a threat to the control of disease vectors. The insect growth regulators (IGR) are a potential alternative to control mosquitoes, including resistant populations. The chitin synthesis inhibitors (CSI) are IGRs, which interfere with the insect molting process and represent one major class of compounds against Aedes aegypti populations resistant to the larvicide organophosphate temephos. In the present study, we evaluated the efficacy of the CSI triflumuron on Culex quinquefasciatus, Aedes albopictus and against several Ae. aegypti field populations. Methods The efficacy of triflumuron, against Cx. quinquefasciatus and Ae. albopictus was evaluated with laboratory strains through dose–response assays. Additionaly, this CSI was tested against seven Ae. aegypti field populations exhibiting distinct resistance levels to both temephos and the pyrethroid deltamethrin. Aedes aegypti populations were exposed to both a dose that inhibits 99% of the adult emergence of mosquitoes from the susceptible reference strain, Rockefeller, (EI99 = 3.95 μg/L) and the diagnostic dose (DD), corresponding to twice the EI99. Results Our results indicate that triflumuron was effective in emergence inhibition (EI) of Cx. quinquefasciatus (EI50= 5.28 μg/L; EI90= 12.47 μg/L) and Ae. albopictus (EI50= 1.59 μg/L; EI90= 2.63 μg/L). Triflumuron was also effective against seven Ae. aegypti Brazilian populations resistant to both temephos and deltamethrin. Exposure of all the Ae. aegypti populations to the triflumuron EI99 of the susceptible reference strain, Rockefeller, resulted in complete inhibition of adult emergence, suggesting no cross-resistance among traditional insecticides and this CSI. However, a positive correlation between temephos resistance and tolerance to triflumuron was observed. Conclusion The results suggest that triflumuron represents a potential tool for the control of disease vectors in public

  10. Influence of Time of Assay on Behavioral Responses of Laboratory and Field Populations Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae) to DEET.

    PubMed

    Tainchum, Krajana; Ritthison, Wanapa; Sathantriphop, Sunaiyana; Tanasilchayakul, Somchai; Manguin, Sylvie; Bangs, Michael J; Chareonviriyaphap, Theeraphap

    2014-11-01

    Knowledge on test conditions that may influence behavioral responses of mosquitoes is critical when excito-repellency tests are conducted. The objective of this study was to investigate the effect of test time differences on normal circadian activity and behavioral responses of field and colonized Aedes aegypti (L.) (=Stegomyia aegypti) and Culex quinquefasciatus Say to DEET, one of the most common synthetic repellent active ingredients available. Two field populations of Ae. aegypti and Cx. quinquefasciatus from Kanchanaburi and Nonthaburi provinces, respectively, and two long-standing laboratory populations, Ae. aegypti obtained from the U.S. Department of Agriculture, and Cx. quinquefasciatus from the Ministry of Public Health, Thailand, were used. Each population was exposed to DEET during two different periods of time (0900-1500 hours) and (2100-0300 hours). Both field and laboratory Cx. quinquefasciatus showed marked differences in spatial repellent escape responses between day and nighttime periods but none in direct contact tests. No significant differences between day and nighttime testing periods were observed with field or laboratory Ae. aegypti, except a higher daytime escape response from noncontact DEET treatment. This study indicates that test time may influence the behavioral avoidance responses and is a potential confounder of excito-repellency evaluations. PMID:26309311

  11. Larvicidal and Pupicidal Activities of Alizarin Isolated from Roots of Rubia cordifolia Against Culex quinquefasciatus Say and Aedes aegypti (L.) (Diptera: Culicidae).

    PubMed

    Gandhi, M R; Reegan, A D; Ganesan, P; Sivasankaran, K; Paulraj, M G; Balakrishna, K; Ignacimuthu, S; Al-Dhabi, N A

    2016-08-01

    The mosquitocidal activities of different fractions and a compound alizarin from the methanol extract of Rubia cordifolia roots were evaluated on larvae and pupae of Culex quinquefasciatus Say and Aedes aegypti (L.) (Diptera: Culicidae). Larvae and pupae were exposed to concentrations of 2.5, 5.0, 7.5 and 10 ppm for fractions and 0.5, 1.0, 1.5 and 2.0 ppm for compound. After 24 h, the mortality was assessed and the LC50 and LC90 values were estimated for larvae and pupae. Among the 23 fractions screened, fraction 2 from the methanol extract of R. cordifolia showed good mosquitocidal activity against C. quinquefasciatus and A. aegypti. LC50 and LC90 values of fraction 2 were 3.53 and 7.26 ppm for C. quinquefasciatus and 3.86 and 8.28 ppm for A. aegypti larvae, and 3.76 and 7.50 ppm for C. quinquefasciatus and 3.92 and 8.05 ppm for A. aegypti pupae, respectively. Further, the isolated compound alizarin presented good larvicidal and pupicidal activities. LC50 and LC90 values of alizarin for larvae were 0.81 and 3.86 ppm against C. quinquefasciatus and 1.31 and 6.04 ppm for A. aegypti larvae, respectively. Similarly, the LC50 and LC90 values of alizarin for pupae were 1.97 and 4.79 ppm for C. quinquefasciatus and 2.05 and 5.59 ppm for A. aegypti pupae, respectively. The structure of the isolated compound was identified on the basis of spectroscopic analysis and compared with reported spectral data. The results indicated that alizarin could be used as a potential larvicide and pupicide.

  12. Mukia maderaspatana (Cucurbitaceae) extract-mediated synthesis of silver nanoparticles to control Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae).

    PubMed

    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.

  13. Chemical constituents and larvicidal potential of Feronia limonia leaf essential oil against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus.

    PubMed

    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.

  14. The effects of herbal essential oils on the oviposition-deterrent and ovicidal activities of Aedes aegypti (Linn.), Anopheles dirus (Peyton and Harrison) and Culex quinquefasciatus (Say).

    PubMed

    Siriporn, P; Mayura, S

    2012-03-01

    The effect of oviposition-deterrent and ovicidal of seven essential oils were evaluated towards three mosquito vectors, Aedes aegypti, Anopheles dirus and Culex quinquefasciatus. The oviposition activity index (OAI) values of six essential oils namely Cananga odorata, Cymbopogon citratus, Cymbopogon nardus, Eucalyptus citriodora, Ocimum basilicum and Syzygium aromaticum indicated that there were more deterrent than the control whereas Citrus sinensis oil acted as oviposition attractant. At higher concentration (10%) of Ca. odorata (ylang ylang flowers) showed high percent effective repellency (ER) against oviposition at 99.4% to Ae. aegypti, 97.1% to An. dirus and 100% to Cx. quinquefasciatus, respectively. The results showed that mean numbers of eggs were lower in treated than in untreated water. In addition, there was an inverse relationship between essential oil concentrations and ovicidal activity. As the concentration of essential oil increased from 1%, 5% and up to 10% conc., the hatching rate decreased. The essential oil of Ca. odorata at 10% conc. gave minimum egg hatch of 10.4% (for Ae. aegypti), 0.8% (for An. dirus) and 1.1% (for Cx. quinquefasciatus) respectively. These results clearly revealed that the essential oil of Ca. odorata served as a potential oviposition-deterrent and ovicidal activity against Ae. aegypti, An. dirus and Cx. quinquefasciatus. PMID:22543614

  15. Serosal cuticle formation and distinct degrees of desiccation resistance in embryos of the mosquito vectors Aedes aegypti, Anopheles aquasalis and Culex quinquefasciatus.

    PubMed

    Vargas, Helena Carolina Martins; Farnesi, Luana Cristina; Martins, Ademir Jesus; Valle, Denise; Rezende, Gustavo Lazzaro

    2014-03-01

    Given their medical importance, mosquitoes have been studied as vectors of parasites since the late 1800's. However, there are still many gaps concerning some aspects of their biology, such as embryogenesis. The embryonic desiccation resistance (EDR), already described in Aedes and Anopheles gambiae mosquitoes, is a peculiar trait. Freshly laid eggs are susceptible to water loss, a condition that can impair their viability. EDR is acquired during embryogenesis through the formation of the serosal cuticle (SC), protecting eggs from desiccation. Nevertheless, conservation of both traits (SC presence and EDR acquisition) throughout mosquito evolution is unknown. Comparative physiological studies with mosquito embryos from different genera, exhibiting distinct evolutionary histories and habits is a feasible approach. In this sense, the process of EDR acquisition of Aedes aegypti, Anopheles aquasalis and Culex quinquefasciatus at 25°C was evaluated. Completion of embryogenesis occurs in Ae. aegypti, An. aquasalis and Cx. quinquefasciatus at, respectively 77.4, 51.3 and 34.3hours after egg laying, Cx. quinquefasciatus embryonic development taking less than half the time of Ae. aegypti. In all cases, EDR is acquired in correlation with SC formation. For both Ae. aegypti and An. aquasalis, EDR and SC appear at 21% of total embryonic development, corresponding to the morphological stage of complete germ band elongation/beginning of germ band retraction. Although phylogenetically closer to Ae. aegypti than to An. aquasalis, Cx. quinquefasciatus acquires both EDR and serosal cuticle later, with 35% of total development, when the embryo already progresses to the middle of germ band retraction. EDR confers distinct egg viability in these species. While Ae. aegypti eggs demonstrated high viability when left up to 72hours in a dry environment, those of An. aquasalis and Cx. quinquefasciatus supported these conditions for only 24 and 5hours, respectively. Our data suggest that

  16. Identification of chemical constituents and larvicidal activity of essential oil from Murraya exotica L. (Rutaceae) against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Krishnamoorthy, Shanmugam; Chandrasekaran, Manivachagam; Raj, Gnanaprakasam Adaikala; Jayaraman, Mahalingam; Venkatesalu, Venugopalan

    2015-05-01

    This study was conducted to evaluate the phytochemical composition and larvicidal effect of leaf essential oil from Murraya exotica against early fourth-instar larvae of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. Gas chromatography (GC) and gas chromatography mass spectrometry (GC-MS) analyses revealed that the essential oil contained 27 components. The major chemical components identified were β-humulene (40.62%), benzyl benzoate (23.96%), β-caryophyllene (7.05%) and α-terpinene (5.66%). The larval mortality was observed after 12 and 24 h of exposure period. The results revealed that essential oil showed varied levels of larvicidal activity against A. aegypti, A. stephensi and C. quinquefasciatus. After 12 h of exposure period, the larvicidal activities were LC₅₀ = 74.7 and LC₉₀ = 152.7 ppm (A. aegypti), LC₅₀ = 56.3 and LC₉₀ = 107.8 ppm (A. stephensi ), and LC₅₀ = 74.4 and LC₉₀ = 136.9 ppm (C. quinquefasciatus) and the larvicidal activities after 24 h of exposure period were LC₅₀ = 35.8 and LC₉₀ = 85.4 ppm (A. aegypti), LC₅₀ = 31.3 and LC₉₀ = 75.1 ppm (A. stephensi), and LC₅₀ = 43.2 and LC₉₀ = 103.2 ppm (C. quinquefasciatus). These results suggest that leaf essential oil from M. exotica is a promising and eco-friendly source of natural larvicidal agent against A. aegypti, A. stephensi and C. quinquefasciatus. PMID:25697880

  17. Identification of chemical constituents and larvicidal activity of essential oil from Murraya exotica L. (Rutaceae) against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Krishnamoorthy, Shanmugam; Chandrasekaran, Manivachagam; Raj, Gnanaprakasam Adaikala; Jayaraman, Mahalingam; Venkatesalu, Venugopalan

    2015-05-01

    This study was conducted to evaluate the phytochemical composition and larvicidal effect of leaf essential oil from Murraya exotica against early fourth-instar larvae of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. Gas chromatography (GC) and gas chromatography mass spectrometry (GC-MS) analyses revealed that the essential oil contained 27 components. The major chemical components identified were β-humulene (40.62%), benzyl benzoate (23.96%), β-caryophyllene (7.05%) and α-terpinene (5.66%). The larval mortality was observed after 12 and 24 h of exposure period. The results revealed that essential oil showed varied levels of larvicidal activity against A. aegypti, A. stephensi and C. quinquefasciatus. After 12 h of exposure period, the larvicidal activities were LC₅₀ = 74.7 and LC₉₀ = 152.7 ppm (A. aegypti), LC₅₀ = 56.3 and LC₉₀ = 107.8 ppm (A. stephensi ), and LC₅₀ = 74.4 and LC₉₀ = 136.9 ppm (C. quinquefasciatus) and the larvicidal activities after 24 h of exposure period were LC₅₀ = 35.8 and LC₉₀ = 85.4 ppm (A. aegypti), LC₅₀ = 31.3 and LC₉₀ = 75.1 ppm (A. stephensi), and LC₅₀ = 43.2 and LC₉₀ = 103.2 ppm (C. quinquefasciatus). These results suggest that leaf essential oil from M. exotica is a promising and eco-friendly source of natural larvicidal agent against A. aegypti, A. stephensi and C. quinquefasciatus.

  18. Mosquito larvicidal properties of silver nanoparticles synthesized using Heliotropium indicum (Boraginaceae) against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Veerakumar, Kaliyan; Govindarajan, Marimuthu; Rajeswary, Mohan; Muthukumaran, Udaiyan

    2014-06-01

    Mosquitoes transmit dreadful diseases to human beings wherein biological control of these vectors using plant-derived molecules would be an alternative to reduce mosquito population. In the present study activity of aqueous leaf extract and silver nanoparticles (AgNPs) synthesized using Helitropium indicum plant leaves against late third instar larvae of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. The range of varying concentrations of synthesized AgNPs (8, 16, 24, 32, and 40 μg/mL) and aqueous leaf extract (30, 60, 90, 120, and 150 μg/mL) were tested against the larvae of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. The synthesized AgNPs from H. indicum were highly toxic than crude leaf aqueous extract in three important vector mosquito species. The results were recorded from UV-Vis spectrum, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy analysis, transmission electron microscopy, and histogram. The synthesized AgNPs showed larvicidal effects after 24 h of exposure. Considerable mortality was evident after the treatment of H. indicum for all three important vector mosquitoes. The LC50 and LC90 values of H. indicum aqueous leaf extract appeared to be effective against A. stephensi (LC50, 68.73 μg/mL; LC90, 121.07 μg/mL) followed by A. aegypti (LC50, 72.72 μg/mL; LC90, 126.86 μg/mL) and C. quinquefasciatus (LC50, 78.74 μg/mL; LC90, 134.39 μg/mL). Synthesized AgNPs against the vector mosquitoes of A. stephensi, A. aegypti, and C. quinquefasciatus had the following LC50 and LC90 values: A. stephensi had LC50 and LC90 values of 18.40 and 32.45 μg/mL, A. aegypti had LC50 and LC90 values of 20.10 and 35.97 μg/mL, and C. quinquefasciatus had LC50 and LC90 values of 21.84 and 38.10 μg/mL. No mortality was observed in the control. These results suggest that the leaf aqueous extracts of H. indicum and green synthesis of silver nanoparticles have the

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

    PubMed

    Phasomkusolsil, Siriporn; Soonwera, Mayura

    2010-07-01

    This study investigated insect bite protection and length of the protection with 30 repellents which were divided into 3 categories: plant oil, essential oil and essential oil with ethyl alcohol, tested against three mosquito species, Aedes aegypti, Anopheles minimus and Culex quinquefasciatus, under laboratory conditions. The plant oil group was comprised of Phlai (Zingiber cassumunar) and Sweet basil (Ocimum basilicum). Both substances were effective as repellents and feeding deterrents against An. minimus (205 minutes protection time and a biting rate of 0.9%), Cx. quinquefasciatus (165 minutes protection time and 0.9% biting rate) and Ae. aegypti (90 minutes protection time and 0.8% biting rate). Essential oil from citronella grass (Cymbopogon nardus) exhibited protection against biting from all 3 mosquito species: for An. minimus, Cx. quinquefasciatus and Ae. aegypti, the results were 130 minutes and 0.9%, 140 minutes and 0.8%, and 115 minutes and 0.8%, respectively. The period of protection time against Ae. aegypti for all repellent candidates tested was lower than the Thai Industrial Standards Institute (TISI) determined time of greater than 2 hours. PMID:21073057

  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.

    PubMed

    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

  1. Insecticidal potency of Aspergillus terreus against larvae and pupae of three mosquito species Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti.

    PubMed

    Ragavendran, Chinnasamy; Natarajan, Devarajan

    2015-11-01

    Microbial control agents offer alternatives to chemical pest control, as they can be more selective than chemical insecticides. The present study evaluates the mosquito larvicidal and pupicidal potential of fungus mycelia using ethyl acetate and methanol solvent extracts produced by Aspergillus terreus against Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti. The A. terreus mycelia were extracted after 15 days from Sabouraud dextrose broth medium. The ethyl acetate extracts showed lethal concentration that kills 50% of the exposed larvae (LC50) and lethal concentration that kills 90% of the exposed larvae (LC90) values of the first, second, third, and fourth instar larvae of An. stephensi (LC50 = 97.410, 102.551, 29.802, and 8.907; LC90 = 767.957, 552.546, 535.474, and 195.677 μg/ml), Cx. quinquefasciatus (LC50 = 89.584, 74.689, 68.265, and 67.40; LC90 = 449.091, 337.355, 518.793, and 237.347 μg/ml), and Ae. aegypti (LC50 = 83.541, 84.418, 80.407, and 95.926; LC90 = 515.464, 443.167, 387.910, and 473.998 μg/ml). Pupicidal activity of mycelium extracts was tested against An. stephensi (LC50 = 25.228, LC90 = 140.487), Cx. quinquefasciatus (LC50 = 54.525, LC90 = 145.366), and Ae. aegypti (LC50 = 10.536, LC90 = 63.762 μg/ml). At higher concentration (500 μg/ml), mortality starts within the first 6 h of exposure. One hundred percent mortality occurs at 24-h exposure. The overall result observed that effective activity against selected mosquito larvae and pupae after 24 h was a dose and time-dependent activity. These ensure that the resultant mosquito population reduction is substantial even where the larvicidal and pupicidal potential is minimal. The FTIR spectra of ethyl acetate extract reflect prominent peaks (3448.32, 3000.36, 2914.59, 2118.73, 1668.21, 1436.87, 1409.02, 954.33, 901.13, and 704.67 cm(-1)). The spectra showed a sharp absorption band at 1314.66 cm(-1) assigned to wagging vibration of

  2. Insecticidal potency of Aspergillus terreus against larvae and pupae of three mosquito species Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti.

    PubMed

    Ragavendran, Chinnasamy; Natarajan, Devarajan

    2015-11-01

    Microbial control agents offer alternatives to chemical pest control, as they can be more selective than chemical insecticides. The present study evaluates the mosquito larvicidal and pupicidal potential of fungus mycelia using ethyl acetate and methanol solvent extracts produced by Aspergillus terreus against Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti. The A. terreus mycelia were extracted after 15 days from Sabouraud dextrose broth medium. The ethyl acetate extracts showed lethal concentration that kills 50% of the exposed larvae (LC50) and lethal concentration that kills 90% of the exposed larvae (LC90) values of the first, second, third, and fourth instar larvae of An. stephensi (LC50 = 97.410, 102.551, 29.802, and 8.907; LC90 = 767.957, 552.546, 535.474, and 195.677 μg/ml), Cx. quinquefasciatus (LC50 = 89.584, 74.689, 68.265, and 67.40; LC90 = 449.091, 337.355, 518.793, and 237.347 μg/ml), and Ae. aegypti (LC50 = 83.541, 84.418, 80.407, and 95.926; LC90 = 515.464, 443.167, 387.910, and 473.998 μg/ml). Pupicidal activity of mycelium extracts was tested against An. stephensi (LC50 = 25.228, LC90 = 140.487), Cx. quinquefasciatus (LC50 = 54.525, LC90 = 145.366), and Ae. aegypti (LC50 = 10.536, LC90 = 63.762 μg/ml). At higher concentration (500 μg/ml), mortality starts within the first 6 h of exposure. One hundred percent mortality occurs at 24-h exposure. The overall result observed that effective activity against selected mosquito larvae and pupae after 24 h was a dose and time-dependent activity. These ensure that the resultant mosquito population reduction is substantial even where the larvicidal and pupicidal potential is minimal. The FTIR spectra of ethyl acetate extract reflect prominent peaks (3448.32, 3000.36, 2914.59, 2118.73, 1668.21, 1436.87, 1409.02, 954.33, 901.13, and 704.67 cm(-1)). The spectra showed a sharp absorption band at 1314.66 cm(-1) assigned to wagging vibration of

  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).

    PubMed

    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. Phytochemical profile and larvicidal properties of seed essential oil from Nigella sativa L. (Ranunculaceae), against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Raj, Gnanaprakasam Adaikala; Chandrasekaran, Manivachagam; Krishnamoorthy, Shanmugam; Jayaraman, Mahalingam; Venkatesalu, Venugopalan

    2015-09-01

    The present study deals with investigation of larvicidal activity and their chemical constituents of the essential oil from the seeds of Nigella sativa L. (Ranunculaceae). Totally, 18 chemical compounds were identified by GC and GC-MS analysis. Thymol (19.13 %) and α-phellandrene (14.9 %) were identified as major chemical components followed by camphor (12.14 %), borneol (11.31 %), and carvacrol (8.65 %). The larval mortality was observed after 12 and 24 h of exposure period. The results revealed that the essential oil were evaluated against the fourth instar larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. After 12 h of exposure period, the larvicidal activities were LC50 = 196.9 and LC90 = 523.5 ppm (A. aegypti), LC50 = 88.1 and LC90 = 272.4 ppm (A.stephensi), and LC50 = 241.6 and LC90 = 545.4 ppm (C. quinquefasciatus), and the larvicidal activities after 24 h of exposure period were LC50 = 99.9 and LC90 = 300.8 ppm (A. aegypti), LC50 = 53.9 and LC90 = 172.6 ppm (A. stephensi), and LC50 = 141.7 and LC90 = 364.0 ppm (C. quinquefasciatus). The results of the present study showed that the essential oil from seeds of N. sativa is inexpensive food formulation and new source of natural larvicidal agent. PMID:26091760

  5. Phytochemical profile and larvicidal properties of seed essential oil from Nigella sativa L. (Ranunculaceae), against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Raj, Gnanaprakasam Adaikala; Chandrasekaran, Manivachagam; Krishnamoorthy, Shanmugam; Jayaraman, Mahalingam; Venkatesalu, Venugopalan

    2015-09-01

    The present study deals with investigation of larvicidal activity and their chemical constituents of the essential oil from the seeds of Nigella sativa L. (Ranunculaceae). Totally, 18 chemical compounds were identified by GC and GC-MS analysis. Thymol (19.13 %) and α-phellandrene (14.9 %) were identified as major chemical components followed by camphor (12.14 %), borneol (11.31 %), and carvacrol (8.65 %). The larval mortality was observed after 12 and 24 h of exposure period. The results revealed that the essential oil were evaluated against the fourth instar larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. After 12 h of exposure period, the larvicidal activities were LC50 = 196.9 and LC90 = 523.5 ppm (A. aegypti), LC50 = 88.1 and LC90 = 272.4 ppm (A.stephensi), and LC50 = 241.6 and LC90 = 545.4 ppm (C. quinquefasciatus), and the larvicidal activities after 24 h of exposure period were LC50 = 99.9 and LC90 = 300.8 ppm (A. aegypti), LC50 = 53.9 and LC90 = 172.6 ppm (A. stephensi), and LC50 = 141.7 and LC90 = 364.0 ppm (C. quinquefasciatus). The results of the present study showed that the essential oil from seeds of N. sativa is inexpensive food formulation and new source of natural larvicidal agent.

  6. Insecticidal potential of Ocimum canum plant extracts against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus larval and adult mosquitoes (Diptera: Culicidae).

    PubMed

    Murugan, Jimmantiyur Madhappan; Ramkumar, Govindaraju; Shivakumar, Muthugoundar Subramanian

    2016-01-01

    Mosquitoes have developed resistance to various synthetic insecticides, making their control increasingly difficult. Insecticides of botanical origin may serve as suitable natural control. This study evaluates the toxic potential of Ocimum canum (Sims) leaf extract and powder against Anopheles stephensi (Liston), Aedes aegypti (Lin) and Culex quinquefasciatus (Say) larval and adult mosquitoes. Larval mortality was observed after 24 h recovery period and adult smoke toxicity observed for 40 min duration at 10 min interval. Methanol extract of O. canum showed highest larval mortality against the larvae of C. quinquefasciatus LC50 = 28.3225, LC90 = 44.1150; Ae. aegypti LC50 = 43.327, LC90 = 61.249; and An. stephensi LC50 = 30.2001, LC90 = 48.2866 ppm. The smoke toxicities were 93% mortality in C. quinquefasciatus, 74% in Ae. aegypti and 79% in An. stephensi adults, respectively, whereas 100% mortality was recorded in the commercial mosquito control. Our results suggest that O. canum leaf extract and powder are natural insecticide, and ideal eco friendly approach for mosquito control.

  7. Effect of temperature on life history traits during immature development of Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae) from Córdoba city, Argentina.

    PubMed

    Grech, Marta G; Sartor, Paolo D; Almirón, Walter R; Ludueña-Almeida, Francisco F

    2015-06-01

    We investigated how ambient temperature under fluctuating conditions affects the larval-pupal immature traits of Aedes aegypti and Culex quinquefasciatus mosquitoes from Córdoba city, Argentina, and established each species development threshold and physiological time. Based on life tables, three cohorts of each mosquito species were reared in the laboratory under small fluctuating temperatures conditions of 15.2±1.7°C, 17.9±1.6°C, 21.6±0.7°C and 25.3±0.4°C for Ae. aegypti, and 16.6±1.7°C, 18.7±1.7°C and 25.2±0.3°C for Cx. quinquefasciatus. Immature development time and survival values, and also thermal development threshold and physiological time were estimated. Development times of all larval and pupal stages of Ae. aegypti and Cx. quinquefasciatus were significantly affected by the rearing temperatures, decreasing when temperature increased. Mean Ae. aegypti total (larva+pupa) development time ranged from 21.9 to 8.6 days, at 15.2 and 25.3°C, whereas, for Cx. quinquefasciatus varied between 23.5 to 9.2 days at 16.6 and 25.2°C, respectively. Larval and pupal survival of both species was affected by different rearing temperatures, increasing in general as temperature increased. For Ae. aegypti the total immature survival ranged from 26% at 15.2°C to 92% at 21.6°C; however, temperature did not have significant effect on this variable. The total immature survival of Cx. quinquefasciatus was significantly and positively affected by temperatures, ranging from 32 to 88%, at 16.6 and 25.2°C. The temperature development threshold and the physiological time estimated for Ae. aegypti and Cx. quinquefasciatus were 11.11°C and 93.74 degree-days, and 10.96°C and 136.87 degree-days, respectively. The results of the present study showed that temperature significantly affects the larval-pupal immature traits of these mosquito species of sanitary importance, from the central region of Argentina. All the parameters recorded are useful for the development of

  8. Larvicidal, ovicidal, and adulticidal efficacy of Erythrina indica (Lam.) (Family: Fabaceae) against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Govindarajan, Marimuthu; Sivakumar, Rajamohan

    2014-02-01

    Mosquitoes are the major vector for the transmission of malaria, dengue fever, yellow fever, filariasis, schistosomiasis, and Japanese encephalitis. Mosquito control is facing a threat because of the emergence of resistance to synthetic insecticides. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticide, this study was undertaken to assess the larvicidal, ovicidal, and adulticidal potential of the crude hexane, benzene, chloroform, ethyl acetate, and methanol solvent extracts from the medicinal plant Erythrina indica against the medically important mosquito vectors, 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 methanol extract of leaf of E. indica against the larvae of A. stephensi, A. aegypti, and C. quinquefasciatus with the LC50 and LC90 values of 69.43, 75.13, and 91.41 ppm and 125.49, 134.31, and 167.14 ppm, respectively. 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 E. indica against A. stephensi, A. aegypti, and C. quinquefasciatus exerted 100 % mortality (zero hatchability) at 150, 200, and 250 ppm, respectively. Control eggs showed above 99.3-100 % hatchability. 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

  9. Low-cost and eco-friendly green synthesis of silver nanoparticles using Feronia elephantum (Rutaceae) against Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti (Diptera: Culicidae).

    PubMed

    Veerakumar, Kaliyan; Govindarajan, Marimuthu; Rajeswary, Mohan; Muthukumaran, Udaiyan

    2014-05-01

    Mosquitoes transmit serious human diseases, causing millions of deaths every year. The use of synthetic insecticides to control vector mosquitoes has caused physiological resistance and adverse environmental effects in addition to high operational cost. Insecticides of synthesized natural products for vector control have been a priority in this area. In the present study, the larvicidal activity of silver nanoparticles (AgNPs) synthesized using Feronia elephantum plant leaf extract against late third-instar larvae of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus was determined. The range of concentrations of synthesized AgNPs (5, 10, 15, 20, and 25 μg mL(-1)) and aqueous leaf extract (25, 50, 75, 100, and 125 μg mL(-1)) were tested against the larvae of A. stephensi, A. aegypti, and C. quinquefasciatus. Larvae were exposed to varying concentrations of aqueous crude extract and synthesized AgNPs for 24 h. Considerable mortality was evident after the treatment of F. elephantum for all three important vector mosquitoes. The synthesized AgNPs from F. elephantum were highly toxic than crude leaf aqueous extract to three important vector mosquito species. The results were recorded from UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy analysis (EDX). Synthesized AgNPs against the vector mosquitoes A. stephensi, A. aegypti, and C. quinquefasciatus had the following LC50 and LC90 values: A. stephensi had LC50 and LC90 values of 11.56 and 20.56 μg mL(-1); A. aegypti had LC50 and LC90 values of 13.13 and 23.12 μg mL(-1); and C. quinquefasciatus had LC50 and LC90 values of 14.19 and 24.30 μg mL(-1). No mortality was observed in the control. These results suggest that the green synthesis of silver nanoparticles using F. elephantum has the potential to be used as an ideal eco-friendly approach for the control of A. stephensi, A. aegypti, and C

  10. Ovicidal and adulticidal potential of leaf and seed extract of Albizia lebbeck (L.) Benth. (Family: Fabaceae) against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi (Diptera: Culicidae).

    PubMed

    Govindarajan, Marimuthu; Rajeswary, Mohan

    2015-05-01

    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. In the present study, hexane, benzene, chloroform, ethyl acetate, and methanol extracts of leaf and seed of Albizia lebbeck were assayed for their toxicity against three important vector mosquitoes, viz., Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. 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. One hundred percent mortality was observed at 250, 200, and 150 ppm for leaf methanol extract and 375, 300, and 225 ppm for seed methanol extract of A. lebbeck against C. quinquefasciatus, Ae. aegypti, and An. stephensi, respectively. The adulticidal activity of plant leaf and seed extracts showed moderate toxic effect on the adult mosquitoes after 24 h of exposure period. However, the highest adulticidal activity was observed in the leaf methanol extract of A. lebbeck against An. stephensi where the LC₅₀ and LC₉₀ values were 65.12 and 117.70 ppm, respectively. Compared to leaf extracts, seeds have low potency against three mosquito species. No mortality was recorded in the control. Our data suggest that the crude hexane, benzene, chloroform, ethyl acetate, and methanol solvent extracts of A. lebbeck have the potential to be used as an eco-friendly approach for the control of the An. stephensi, Ae. aegypti, and C. quinquefasciatus. These results suggest that the leaf and seed extracts have the potential to be used as an ideal

  11. Ovicidal and adulticidal potential of leaf and seed extract of Albizia lebbeck (L.) Benth. (Family: Fabaceae) against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi (Diptera: Culicidae).

    PubMed

    Govindarajan, Marimuthu; Rajeswary, Mohan

    2015-05-01

    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. In the present study, hexane, benzene, chloroform, ethyl acetate, and methanol extracts of leaf and seed of Albizia lebbeck were assayed for their toxicity against three important vector mosquitoes, viz., Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. 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. One hundred percent mortality was observed at 250, 200, and 150 ppm for leaf methanol extract and 375, 300, and 225 ppm for seed methanol extract of A. lebbeck against C. quinquefasciatus, Ae. aegypti, and An. stephensi, respectively. The adulticidal activity of plant leaf and seed extracts showed moderate toxic effect on the adult mosquitoes after 24 h of exposure period. However, the highest adulticidal activity was observed in the leaf methanol extract of A. lebbeck against An. stephensi where the LC₅₀ and LC₉₀ values were 65.12 and 117.70 ppm, respectively. Compared to leaf extracts, seeds have low potency against three mosquito species. No mortality was recorded in the control. Our data suggest that the crude hexane, benzene, chloroform, ethyl acetate, and methanol solvent extracts of A. lebbeck have the potential to be used as an eco-friendly approach for the control of the An. stephensi, Ae. aegypti, and C. quinquefasciatus. These results suggest that the leaf and seed extracts have the potential to be used as an ideal

  12. Larvicidal and repellent properties of Streptomyces sp. VITJS4 crude extract against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Naine, S Jemimah; Devi, C Subathra

    2014-01-01

    The aim of the present study was to assess the larvicidal and repellent properties of marine Streptomyces sp. VITJS4 crude extracts. The marine soil samples were collected from the Puducherry coast, Tamil Nadu, India. The isolate Streptomyces sp. VITJS4 was taxonomically characterized and identified. The ethyl acetate crude extract tested for larvicidal property showed 100% mortality for all the 3 species after 24 h exposure against the early fourth instar larvae of malarial vector--Anopheles stephensi at 50% and 90% lethal concentration (LC50 = 132.86, LC90 396.14 ppm); dengue vector--Aedes aegypti (LC50 = 112.78, LC90 336.42 ppm) and filariasis vector--Culex quinquefasciatus (LC50 = 156.53, LC90 468.37 ppm). The Streptomyces sp. VITJS4 solvent extracts of hexane, ethyl acetate, benzene, chloroform and methanol were tested for repellent activity against A. stephensi, A. aegypti and C. quinquefasciatus. The ethyl acetate extract showed complete protection for 210 min at 6 mg/cm2 against these mosquito bites. The crude extract was analyzed further for Fourier Transform-infrared spectroscopy (FT-IR) analysis. In addition to the importance of bioactive compounds, the utilization of Streptomyces sp. VITJS4 crude extracts revealed effective larvicidal and repellent activity against the vectors, which perhaps represents a promising tool in the management of mosquito control. PMID:25546945

  13. Larvicidal activity of neem and karanja oil cakes against mosquito vectors, Culex quinquefasciatus (say), Aedes aegypti (L.) and Anopheles stephensi (L.).

    PubMed

    Shanmugasundaram, R; Jeyalakshmi, T; Dutt, M Sunil; Murthy, P Balakrishna

    2008-01-01

    Larvicidal effect of neem (Azadirachta indica) and karanja (Pongamia glabra) oil cakes (individuals and combination) was studied against mosquito species. Both the oil cakes showed larvicidal activity against the mosquito species tested. The combination of neem and karanja oil cakes in equal proportion proved to have better effect than the individual treatments. The combination of the two oil cakes recorded an LC95 of 0.93, 0.54 and 0.77% against the mosquitoes, Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi respectively The increase in efficacy of the combination treatment over individuals in all the mosquito larvae tested was found to range about 4 to 10 fold in terms of LC50 and 2 to 6 fold in terms of LC95.

  14. Larvicidal, pupicidal, repellent and adulticidal activity of Citrus sinensis orange peel extract against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Murugan, Kadarkarai; Mahesh Kumar, Palanisamy; Kovendan, Kalimuthu; Amerasan, Duraisamy; Subrmaniam, Jayapal; Hwang, Jiang-Shiou

    2012-10-01

    Mosquitoes are the carriers of severe and well-known illnesses such as malaria, arboviral encephalitis, dengue fever, chikunguniya fever, West Nile virus and yellow fever. These diseases produce significant morbidity and mortality in humans and livestock around the world. The present study explored the effects of orange peel ethanol extract of Citrus sinensis on larvicidal, pupicidal, repellent and adulticidal activity against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. The orange peel material was shade dried at room temperature and powdered coarsely. From orange peel, 300 g powdered was macerated with 1 L of ethanol sequentially for a period of 72 h each and filtered. The yields of the orange peel ethanol crude extract of C. sinensis 13.86 g, respectively. The extracts were concentrated at reduced temperature on a rotary vacuum evaporator and stored at a temperature of 4 °C. The larvicidal, pupicidal and adult mortality was observed after 24 h of exposure; no mortality was observed in the control group. For C. sinensis, the median lethal concentration values (LC(50)) observed for the larvicidal and pupicidal activities against mosquito vector species A. stephensi first to fourth larval instars and pupae were 182.24, 227.93, 291.69, 398.00 and 490.84 ppm; A. aegypti values were 92.27, 106.60, 204.87, 264.26, 342.45, 436.93 and 497.41 ppm; and C. quinquefasciatus values were 244.70, 324.04, 385.32, 452.78 and 530.97 ppm, respectively. The results of maximum repellent activity were observed at 450 ppm in ethanol extracts of C. sinensis and the mean complete protection time ranged from 150 to 180 min was tested. The ethanol extract of C. sinensis showed 100% repellency in 150 min and showed complete protection in 90 min at 350 ppm against A. stephensi, A. aegypti and C. quinquefasciatus, respectively. The adult mortality was found in ethanol extract of C. sinensis with the LC(50) and LC(90) values of 272.19 and 457.14 ppm, A. stephensi; 289.62 and

  15. Green synthesis of silver nanoparticles using Sida acuta (Malvaceae) leaf extract against Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti (Diptera: Culicidae).

    PubMed

    Veerakumar, Kaliyan; Govindarajan, Marimuthu; Rajeswary, Mohan

    2013-12-01

    Mosquitoes act as a vector for most of the life-threatening diseases like malaria, yellow fever, dengue fever, chikungunya fever, filariasis, encephalitis, West Nile Virus infection, etc. Under the Integrated Mosquito Management, emphasis was given on the application of alternative strategies in mosquito control. The continuous application of synthetic insecticides causes development of resistance in vector species, biological magnification of toxic substances through the food chain, and adverse effects on environmental quality and nontarget organisms including human health. Application of active toxic agents from plant extracts as an alternative mosquito control strategy was available from ancient times. These are nontoxic, easily available at affordable prices, biodegradable, and show broad-spectrum target-specific activities against different species of vector mosquitoes. In the present study, the larvicidal activity of silver nanoparticles (AgNPs) synthesized using Sida acuta plant leaf extract against late third instar larvae of Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti was determined. Range of concentrations of synthesized AgNPs (10, 20, 30, 40, and 50 μg/mL) and aqueous leaf extract (50, 100, 150, 200, and 250 μg/mL) were tested against the larvae of C. quinquefasciatus, A. stephensi and A. aegypti. The synthesized AgNPs from S. acuta leaf were highly toxic than crude leaf aqueous extract in three important vector mosquito species. The results were recorded from UV-Vis spectrum, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy analysis. Larvae were exposed to varying concentrations of aqueous crude extract and synthesized AgNPs for 24 h. Considerable mortality was evident after the treatment of S. acuta for all three important vector mosquitoes. The LC50 and LC90 values of S. acuta aqueous leaf extract appeared to be most effective

  16. Cyt1Ab1 and Cyt2Ba1 from Bacillus thuringiensis subsp. medellin and B. thuringiensis subsp. israelensis Synergize Bacillus sphaericus against Aedes aegypti and Resistant Culex quinquefasciatus (Diptera: Culicidae)

    PubMed Central

    Wirth, Margaret C.; Delécluse, Armelle; Walton, William E.

    2001-01-01

    The interaction of two cytolytic toxins, Cyt1Ab from Bacillus thuringiensis subsp. medellin and Cyt2Ba from Bacillus thuringiensis subsp. israelensis, with Bacillus sphaericus was evaluated against susceptible and resistant Culex quinquefasciatus and the nonsensitive species Aedes aegypti. Mixtures of B. sphaericus with either cytolytic toxin were synergistic, and B. sphaericus resistance in C. quinquefasciatus was suppressed from >17,000- to 2-fold with a 3:1 mixture of B. sphaericus and Cyt1Ab. This trait may prove useful for combating insecticide resistance and for improving the activity of microbial insecticides. PMID:11425753

  17. Physical features and chitin content of eggs from the mosquito vectors Aedes aegypti, Anopheles aquasalis and Culex quinquefasciatus: Connection with distinct levels of resistance to desiccation.

    PubMed

    Farnesi, Luana Cristina; Menna-Barreto, Rubem Figueiredo Sadok; Martins, Ademir Jesus; Valle, Denise; Rezende, Gustavo Lazzaro

    2015-12-01

    Mosquito eggs are laid in water but freshly laid eggs are susceptible to dehydration, if their surroundings dry out at the first hours of development. During embryogenesis of different mosquito vectors the serosal cuticle, an extracellular matrix, is produced; it wraps the whole embryo and becomes part of the eggshell. This cuticle is an essential component of the egg resistance to desiccation (ERD). However, ERD is variable among species, sustaining egg viability for different periods of time. While Aedes aegypti eggs can survive for months in a dry environment (high ERD), those of Anopheles aquasalis and Culex quinquefasciatus in the same condition last, respectively, for one day (medium ERD) or a few hours (low ERD). Resistance to desiccation is determined by the rate of water loss, dehydration tolerance and total amount of water of a given organism. The ERD variability observed among mosquitoes probably derives from diverse traits. We quantified several attributes of whole eggs, potentially correlated with the rate of water loss: length, width, area, volume, area/volume ratio and weight. In addition, some eggshell aspects were also evaluated, such as absolute and relative weight, weight/area relationship (herein called surface density) and chitin content. Presence of chitin specifically in the serosal cuticle as well as aspects of endochorion external surface were also investigated. Three features could be related to differences on ERD levels: chitin content, directly related to ERD, the increase in the egg volume during embryogenesis and the eggshell surface density, which were both inversely related to ERD. Although data suggest that the amount of chitin in the eggshell is relevant for egg impermeability, the participation of other yet unidentified eggshell attributes must be considered in order to account for the differences in the ERD levels observed among Ae. aegypti, An. aquasalis and Cx. quinquefasciatus. PMID:26514070

  18. Genetic Characterization of Spondweni and Zika Viruses and Susceptibility of Geographically Distinct Strains of Aedes aegypti, Aedes albopictus and Culex quinquefasciatus (Diptera: Culicidae) to Spondweni Virus

    PubMed Central

    Haddow, Andrew D.; Nasar, Farooq; Guzman, Hilda; Ponlawat, Alongkot; Jarman, Richard G.; Tesh, Robert B.; Weaver, Scott C.

    2016-01-01

    Background Zika virus (ZIKV) has extended its known geographic distribution to the New World and is now responsible for severe clinical complications in a subset of patients. While substantial genetic and vector susceptibility data exist for ZIKV, less is known for the closest related flavivirus, Spondweni virus (SPONV). Both ZIKV and SPONV have been known to circulate in Africa since the mid-1900s, but neither has been genetically characterized by gene and compared in parallel. Furthermore, the susceptibility of peridomestic mosquito species incriminated or suspected in the transmission of ZIKV to SPONV was unknown. Methodology/Principal Findings In this study, two geographically distinct strains of SPONV were genetically characterized and compared to nine genetically and geographically distinct ZIKV strains. Additionally, the susceptibility of both SPONV strains was determined in three mosquito species. The open reading frame (ORF) of the SPONV 1952 Nigerian Chuku strain, exhibited a nucleotide and amino acid identity of 97.8% and 99.2%, respectively, when compared to the SPONV 1954 prototype South African SA Ar 94 strain. The ORF of the SPONV Chuku strain exhibited a nucleotide and amino acid identity that ranged from 68.3% to 69.0% and 74.6% to 75.0%, respectively, when compared to nine geographically and genetically distinct strains of ZIKV. The ORF of the nine African and Asian lineage ZIKV strains exhibited limited nucleotide divergence. Aedes aegypti, Ae. albopictus and Culex quinquefasciatus susceptibility and dissemination was low or non-existent following artificial infectious blood feeding of moderate doses of both SPONV strains. Conclusions/Significance SPONV and ZIKV nucleotide and amino acid divergence coupled with differences in geographic distribution, ecology and vector species support previous reports that these viruses are separate species. Furthermore, the low degree of SPONV infection or dissemination in Ae. albopictus, Ae. aegypti and Cx

  19. Efficacy of essential oil from Cananga odorata (Lamk.) Hook.f. & Thomson (Annonaceae) against three mosquito species Aedes aegypti (L.), Anopheles dirus (Peyton and Harrison), and Culex quinquefasciatus (Say).

    PubMed

    Soonwera, Mayura

    2015-12-01

    The essential oil of Cananga odorata flowers was evaluated for oviposition-deterrent, ovicidal, insecticidal, and repellent activities toward three mosquito species: Aedes aegypti, Anopheles dirus, and Culex quinquefasciatus. Oviposition deterrence of the oil was evaluated on gravid females using oviposition deterrence bioassay. The results showed that 10 % Ca. odorata exhibited high percent effective repellency against oviposition at 99.4 % to Ae. aegypti, 97.1 % to An. dirus, and 100 % to Cx. quinquefasciatus. Ca. odorata oil was tested for ovicidal activity. Regression equations revealed that the ovicidal rates were positively correlated with the concentrations of the essential oil. As the concentration of essential oil increased from 1, 5, and up to 10 % concentration, the ovicidal rate increased accordingly. Larvicidal activity of the oils was used on immature stages (third and fourth instar lavae and pupae). The maximum larval mortality was found with 10 % Ca. odorata against immature stages, and there were LC50 values ranged from 10.4 to 10.5 % (for Ae. aegypti), <1 % (for An. dirus), and <1 % (for Cx. quinquefasciatus). Adulticidal properties were evaluated with unfed females. Ten percent Ca. odorata oil had high knockdown rates against the three mosquito species at 96 % (for Ae. aegypti), 98.4 % (for An. dirus), and 100 % (for Cx. quinquefasciatus), with EC50 values of 6.2, 4.7, and 5.4 %, respectively. It gave moderate mortality rates after 24 and 48 h of exposure. Ca. odorata oil was assessed for repellency to females by using the modified K&D module. Ten percent Ca. odorata oil gave the strongest value against Ae. aegypti, An. dirus, and Cx. quinquefasciatus, with percentage repellency of 66, 92, and 90 %, respectively. This study demonstrates the potential for the essential oil of Ca. odorata essential oil to be used as a botanical insecticide against three mosquito species.

  20. Efficacy of essential oil from Cananga odorata (Lamk.) Hook.f. & Thomson (Annonaceae) against three mosquito species Aedes aegypti (L.), Anopheles dirus (Peyton and Harrison), and Culex quinquefasciatus (Say).

    PubMed

    Soonwera, Mayura

    2015-12-01

    The essential oil of Cananga odorata flowers was evaluated for oviposition-deterrent, ovicidal, insecticidal, and repellent activities toward three mosquito species: Aedes aegypti, Anopheles dirus, and Culex quinquefasciatus. Oviposition deterrence of the oil was evaluated on gravid females using oviposition deterrence bioassay. The results showed that 10 % Ca. odorata exhibited high percent effective repellency against oviposition at 99.4 % to Ae. aegypti, 97.1 % to An. dirus, and 100 % to Cx. quinquefasciatus. Ca. odorata oil was tested for ovicidal activity. Regression equations revealed that the ovicidal rates were positively correlated with the concentrations of the essential oil. As the concentration of essential oil increased from 1, 5, and up to 10 % concentration, the ovicidal rate increased accordingly. Larvicidal activity of the oils was used on immature stages (third and fourth instar lavae and pupae). The maximum larval mortality was found with 10 % Ca. odorata against immature stages, and there were LC50 values ranged from 10.4 to 10.5 % (for Ae. aegypti), <1 % (for An. dirus), and <1 % (for Cx. quinquefasciatus). Adulticidal properties were evaluated with unfed females. Ten percent Ca. odorata oil had high knockdown rates against the three mosquito species at 96 % (for Ae. aegypti), 98.4 % (for An. dirus), and 100 % (for Cx. quinquefasciatus), with EC50 values of 6.2, 4.7, and 5.4 %, respectively. It gave moderate mortality rates after 24 and 48 h of exposure. Ca. odorata oil was assessed for repellency to females by using the modified K&D module. Ten percent Ca. odorata oil gave the strongest value against Ae. aegypti, An. dirus, and Cx. quinquefasciatus, with percentage repellency of 66, 92, and 90 %, respectively. This study demonstrates the potential for the essential oil of Ca. odorata essential oil to be used as a botanical insecticide against three mosquito species. PMID:26337270

  1. Spectral and HRTEM analyses of Annona muricata leaf extract mediated silver nanoparticles and its Larvicidal efficacy against three mosquito vectors Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti.

    PubMed

    Santhosh, Shanthi Bhupathi; Ragavendran, Chinnasamy; Natarajan, Devarajan

    2015-12-01

    Mosquitoes transmit various diseases which mainly affect the human beings and every year cause millions of deaths globally. Currently available chemical and synthetic mosquitocidal agents pose severe side effects, pollute the environment vigorously, and become resistance. There is an urgent need to identify and develop the cost effective, compatible and eco-friendly product for mosquito control. The present study was aimed to find out the larvicidal potential of aqueous crude extract and green synthesized silver nanoparticles (AgNPs) from Annona muricata leaves were tested against fourth instar larvae of three important mosquitoes i.e. Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti using different concentrations of AgNPs (10, 20, 30, 40 and 50 ppm) and the aqueous leaf extract (100, 200, 300, 400, and 500 ppm) for 24 and 48 h. The maximum mortality was noticed in AgNPs than aqueous leaf extract of A. muricata against tested mosquitoes with least LC50 values of 37.70, 31.29, and 20.65 ppm (24h) and 546.7, 516.2, and 618.4 ppm (48 h), respectively. All tested concentrations of AgNps exhibited 100% mortality in A. aegypti larvae at 48 hour observation. In addition, the plant mediated AgNPs were characterized by UV-vis spectrum, Fourier transform infrared spectroscopy, particle size analyser, X-ray diffraction, high resonance transmission electron microscopy, and energy-dispersive X-ray spectroscopy analysis for confirmation of nanoparticle synthesis. Based on the findings of the study suggests that the use of A. muricata plant mediated AgNPs can act as an alternate insecticidal agents for controlling target mosquitoes.

  2. Spectral and HRTEM analyses of Annona muricata leaf extract mediated silver nanoparticles and its Larvicidal efficacy against three mosquito vectors Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti.

    PubMed

    Santhosh, Shanthi Bhupathi; Ragavendran, Chinnasamy; Natarajan, Devarajan

    2015-12-01

    Mosquitoes transmit various diseases which mainly affect the human beings and every year cause millions of deaths globally. Currently available chemical and synthetic mosquitocidal agents pose severe side effects, pollute the environment vigorously, and become resistance. There is an urgent need to identify and develop the cost effective, compatible and eco-friendly product for mosquito control. The present study was aimed to find out the larvicidal potential of aqueous crude extract and green synthesized silver nanoparticles (AgNPs) from Annona muricata leaves were tested against fourth instar larvae of three important mosquitoes i.e. Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti using different concentrations of AgNPs (10, 20, 30, 40 and 50 ppm) and the aqueous leaf extract (100, 200, 300, 400, and 500 ppm) for 24 and 48 h. The maximum mortality was noticed in AgNPs than aqueous leaf extract of A. muricata against tested mosquitoes with least LC50 values of 37.70, 31.29, and 20.65 ppm (24h) and 546.7, 516.2, and 618.4 ppm (48 h), respectively. All tested concentrations of AgNps exhibited 100% mortality in A. aegypti larvae at 48 hour observation. In addition, the plant mediated AgNPs were characterized by UV-vis spectrum, Fourier transform infrared spectroscopy, particle size analyser, X-ray diffraction, high resonance transmission electron microscopy, and energy-dispersive X-ray spectroscopy analysis for confirmation of nanoparticle synthesis. Based on the findings of the study suggests that the use of A. muricata plant mediated AgNPs can act as an alternate insecticidal agents for controlling target mosquitoes. PMID:26410042

  3. Effect of Novaluron (Rimon 10 EC) on the mosquitoes Anopheles albimanus, Anopheles pseudopunctipennis, Aedes aegypti, Aedes albopictus and Culex quinquefasciatus from Chiapas, Mexico.

    PubMed

    Arredondo-Jiménez, J I; Valdez-Delgado, K M

    2006-12-01

    Dengue fever is a serious problem in Mexico and vector control has not been effective enough at preventing outbreaks. Malaria is largely under control, but it is important that new control measures continue to be developed. Novaluron, a novel host-specific insect growth regulator and chitin synthesis inhibitor, has proved to be effective against agricultural pests, but its efficacy against larval mosquito vectors under field conditions remains unknown. In accordance with the World Health Organization Pesticide Evaluation Scheme, phase I, II and III studies were conducted to evaluate the efficacy and residual effect of Novaluron (Rimon 10 EC, Makhteshim, Beer-Sheva, Israel) on the malaria vectors Anopheles albimanus Wiedemann (Diptera: Culicidae) and Anopheles pseudopunctipennis Theobald, the dengue vectors Aedes aegypti (L) and Aedes albopictus Skuse and the nuisance mosquito Culex quinquefasciatus Say. Laboratory susceptibility tests yielded diagnostic concentrations for all five target species. Field trials to identify the optimum field dosage of Novaluron against Anopheles mosquitoes were carried out under semi-natural conditions in artificial plots and in vessels with wild mosquitoes. Efficacy was measured by monitoring mortality of larvae and pupae and the percentage of inhibition of emergence from floating cages. Dosages of Novaluron for field tests were based on pupal LC(99) (lethal concentration 99%) of An. pseudopunctipennis (0.166 mg/L) in plots and average pupal LC(99) of Ae. aegypti and Ae. albopictus (0.55 mg/L). At all dosages tested, Novaluron significantly reduced larval populations of An. albimanus, Culex coronator Dyar & Knab, Ae. albopictus and Cx. quinquefasciatus by approximately 90%, inhibited adult emergence of An. albimanus and An. pseudopunctipennis by approximately 97% for almost 4 months in experimental plots, and inhibited adult emergence of Ae. aegypti and Ae. albopictus by approximately 97% for up to 14 weeks. Recommended dosages of

  4. Mosquito larvicidal potential of silver nanoparticles synthesized using Chomelia asiatica (Rubiaceae) against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Muthukumaran, Udaiyan; Govindarajan, Marimuthu; Rajeswary, Mohan

    2015-03-01

    Mosquitoes transmit serious human diseases, causing millions of deaths every 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 a serious concern in developing countries like India due to the lack of general awareness, development of resistance, and socioeconomic reasons. Today, nanotechnology is a promising research domain which has a wide ranging application in vector control programs. These are nontoxic, easily available at affordable prices, biodegradable, and show broad-spectrum target-specific activities against different species of vector mosquitoes. In the present study, larvicidal activity of aqueous leaf extract and silver nanoparticles (AgNPs) synthesized using C. asiatica plant leaves against late third instar larvae of Anopheles stephensi, Aedes aegypti, and Cx. quinquefasciatus. The range of varying concentrations of synthesized AgNPs (8, 16, 24, 32, and 40 μg/mL) and aqueous leaf extract (40, 80, 120, 160, and 200 μg/mL) were tested against the larvae of An. stephensi, Ae. aegypti, and Cx. quinquefasciatus. The synthesized AgNPs from C. asiatica were highly toxic than crude leaf aqueous extract in three important vector mosquito species. The results were recorded from UV-Vis spectrum, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy analysis (EDX). Considerable mortality was evident after the treatment of C. asiatica for all three important vector mosquitoes. The LC50 and LC90 values of C. asiatica aqueous leaf extract appeared to be effective against An. stephensi (LC50, 90.17 μg/mL; LC90, 165.18 μg/mL) followed by Ae. aegypti (LC50, 96.59 μg/mL; LC90, 173.83 μg/mL) and Cx. quinquefasciatus (LC50, 103.08 μg/mL; LC90, 183.16 μg/mL). Synthesized AgNPs against the vector mosquitoes of An. stephensi, Ae. aegypti, and Cx. quinquefasciatus had the following LC50 and LC90

  5. Mosquito larvicidal potential of silver nanoparticles synthesized using Chomelia asiatica (Rubiaceae) against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Muthukumaran, Udaiyan; Govindarajan, Marimuthu; Rajeswary, Mohan

    2015-03-01

    Mosquitoes transmit serious human diseases, causing millions of deaths every 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 a serious concern in developing countries like India due to the lack of general awareness, development of resistance, and socioeconomic reasons. Today, nanotechnology is a promising research domain which has a wide ranging application in vector control programs. These are nontoxic, easily available at affordable prices, biodegradable, and show broad-spectrum target-specific activities against different species of vector mosquitoes. In the present study, larvicidal activity of aqueous leaf extract and silver nanoparticles (AgNPs) synthesized using C. asiatica plant leaves against late third instar larvae of Anopheles stephensi, Aedes aegypti, and Cx. quinquefasciatus. The range of varying concentrations of synthesized AgNPs (8, 16, 24, 32, and 40 μg/mL) and aqueous leaf extract (40, 80, 120, 160, and 200 μg/mL) were tested against the larvae of An. stephensi, Ae. aegypti, and Cx. quinquefasciatus. The synthesized AgNPs from C. asiatica were highly toxic than crude leaf aqueous extract in three important vector mosquito species. The results were recorded from UV-Vis spectrum, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy analysis (EDX). Considerable mortality was evident after the treatment of C. asiatica for all three important vector mosquitoes. The LC50 and LC90 values of C. asiatica aqueous leaf extract appeared to be effective against An. stephensi (LC50, 90.17 μg/mL; LC90, 165.18 μg/mL) followed by Ae. aegypti (LC50, 96.59 μg/mL; LC90, 173.83 μg/mL) and Cx. quinquefasciatus (LC50, 103.08 μg/mL; LC90, 183.16 μg/mL). Synthesized AgNPs against the vector mosquitoes of An. stephensi, Ae. aegypti, and Cx. quinquefasciatus had the following LC50 and LC90

  6. The impact of CO2 on collection of Aedes aegypti (Linnaeus) and Culex quinquefasciatus Say by BG-Sentinel(r) traps in Manaus, Brazil

    PubMed Central

    de Ázara, Tatiana Mingote Ferreira; Degener, Carolin Marlen; Roque, Rosemary Aparecida; Ohly, Jörg Johannes; Geier, Martin; Eiras, Álvaro Eduardo

    2013-01-01

    Carbon dioxide (CO2) is an important component for activating and attracting host-seeking mosquitoes. The BG-Sentinel(r) trap is a well-established monitoring tool for capturing Culicidae, but CO2 role for the trap effectiveness has not been evaluated in highly urbanised areas. The objective was to evaluate the effectiveness of BG-Sentinel traps baited with and without CO2 for capturing urban mosquitoes. Fifteen areas were selected within the city of Manaus, Brazil, where four BG-Sentinels were operated for 24 h, two of them with CO2 and two without CO2. Captured Aedes aegypti females were dissected for the determination of their parity status. A significantly higher proportion of traps (from 32-79%) were positive for female Ae. aegypti when using the BG-Sentinel with CO2 (χ2 = 11.0271, p ≤ 0.001). Catches of female Culex spp were six times higher in CO2 traps (Mann-Whitney U test = 190.5; p = 0.001). Parity rates were similar for both traps. This study showed that CO2 has primarily an enhancing effect on the efficacy of BG-Sentinel for capturing Culex spp in Manaus. For Ae. aegypti, the positivity rate of the trap was increased, when CO2 was added. PMID:23579804

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

    PubMed Central

    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

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

    PubMed

    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.

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

    PubMed

    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

    2016-01-01

    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. PMID:27599470

  10. Spectral sensitivity of the nocturnal mosquito, Culex quinquefasciatus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The nocturnal mosquito, Culex quinquefasciatus,as a vector of West Nile virus is the target of many surveillance and control efforts. Surveillance of this species primarily consists of light traps baited with a variety of chemical lures. While much research has focused on optimization of the olfa...

  11. Tagetes erecta Linn. and its mosquitocidal potency against Culex quinquefasciatus

    PubMed Central

    Nikkon, Farjana; Habib, M Rowshanul; Saud, Zahangir Alam; Karim, M Rezaul

    2011-01-01

    Objective To investigate mosquitocidal effects of ethanolic extract of flowers of Tagetes erecta (T. erecta) and its chloroform and petroleum ether soluble fractions against the larvae of Culex quinquefasciatus (Cx. quinquefasciatus). Methods The fresh flowers of T. erecta were extracted in cold with ethanol (5.0 L) and after concentration, the ethanol extract was fractionated with chloroform and petroleum ether to afford a brownish syrupy suspension of ethanol extract (50.0 g), petroleum ether soluble fraction (18.6 g) and chloroform soluble fraction (23.8 g). The larvicidal effect of ethanol extract and their solvent fractions were determined by the standard procedure of WHO against different instars of Cx. quinquefasciatus. Results Among the tested samples the chloroform soluble fractions showed the highest toxicity and consequently, the lowest LC50 values (14.14 µg/mL, 17.06 µg/mL, 36.88 µg/mL and 75.48 µg/mL) for all the instars larvae of Cx. quinquefasciatus. The larvae showed comparative tolerance in the course of increasing age and time. Conclusions It can be concluded that the flowers of T. erecta are very effective natural larvicide and could be useful against Cx. quinquefasciatus. PMID:23569756

  12. Cross resistances in spinosad-resistant Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Su, Tianyun; Cheng, Min-Lee

    2014-03-01

    A Culex quinquefasciatus Say colony was selected for 45 generations at LC70-90 levels using Natular XRG, a granular formulation of 2.5% spinosad for induction of spinosad resistance. Resistance to spinosad was noticed in early generations (F1-F9). Resistance levels increased gradually from generations F11-F35, and elevated significantly from generation F37 through F47, when resistance ratios reached 2,845-2,907-fold at LC50 and 11,948-22,928-fold at LC90 The spinosad-resistant Cx. quinquefasciatus colony was found not to be cross-resistant to Bacillus thuringiensis israelensis (Bti), a combination of Bti and Bacillus sphaericus, methoprene, pyriproxyfen, diflubenzuron, novaluron, temephos, or imidacloprid. However, it showed various levels of cross-resistance to B. sphaericus, spinetoram, abamectin, and fipronil. Conversely, a laboratory colony of Cx. quinquefasciatus that is highly resistant to B. sphaericus did not show cross-resistance to spinosad and spinetoram. Field-collected and laboratory-selected Cx. quinquefasciatus that showed low to moderate resistance to methoprene did not show cross-resistance to spinosad and spinetoram. Mechanisms of cross-resistance among several biorational pesticides were discussed according to their modes of actions.

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

    PubMed

    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.

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

    PubMed Central

    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

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

    PubMed

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

    PubMed Central

    2011-01-01

    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. quinquefasciatus were also

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

    PubMed

    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.

  18. Genetic-morphometric variation in Culex quinquefasciatus from Brazil and La Plata, Argentina.

    PubMed

    Morais, Sirlei Antunes de; Moratore, Camila; Suesdek, Lincoln; Marrelli, Mauro Toledo

    2010-08-01

    Variation among natural populations of Culex (Culex) quinquefasciatus Say is associated with different vectorial capacities. The species Cx. quinquefasciatus is present in the equatorial, tropical and subtropical zones in the Brazilian territory, with intermediate forms between Cx. quinquefasciatus and Culex pipiens occurring in regions of latitudes around 33°-35° S. Herein, we studied geographically distinct populations of Cx. quinquefasciatus by genetic characterization and analysis of intra-specific wing morphometrics. After morphological analysis, molecular characterization of Cx. quinquefasciatus and intermediate forms was performed by polymerase chain reaction of the polymorphic nuclear region of the second intron of the acetylcholinesterase locus. Additionally, the morphology of adult female wings collected from six locations was analyzed. Wing centroid sizes were significantly different between some geographical pairs. Mean values of R2/R2+3 differed significantly after pairwise comparisons. The overall wing shape represented by morphometric characters could be divided into two main groupings. Our data suggest that Brazilian samples are morphologically and genetically distinct from the Argentinean samples and also indicated a morphological distinction between northern and southern populations of Brazilian Cx. quinquefasciatus. We suggest that wing morphology may be used for preliminary assessment of population structure of Cx. quinquefasciatusin Brazil. PMID:20835615

  19. Laboratory and field evaluation of medicinal plant extracts against filarial vector, Culex quinquefasciatus Say (Diptera: Culicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, chemical extracts of Jatropha curcas, Hyptis suaveolens, Abutilon indicum, and Leucas aspera were tested for toxicity to larvae of the filariasis vector Culex quinquefasciatus. Respective median lethal concentrations (LC50) for hexane, chloroform, ethyl acetate, and methanol extracts...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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. Age modifies effect of body size on fecundity in Culex quinquefasciatus Say (Diptera: Culicidae).

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fecundity of mosquitoes can vary with many factors, and can have a strong effect on population growth. This study reports the effects of body size, blood meal size and age on reproductive output of nulliparous Culex quinquefasciatus, a vector of arboviruses and other pathogens. Mated adult female m...

  2. Pedilanthus tithymaloides (Euphorbiaceae) leaf extract phytochemicals: Toxicity to the filariasis vector, Culex quinquefasciatus (Diptera: Culicidae).

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ethanolic extract of Pedilanthus tithymaloides (Euphorbiaceae) leaves was tested for biological activiity against the eggs, larvae, and pupae of Culex quinquefasciatus. Significant (P <0.0001) mortality effects were observed in each life stage. In eggs, these effects ranged from 7 to 14% at the 2 ...

  3. Genome-Based Microsatellite Development in the Culex pipiens Complex and Comparative Microsatellite Frequency with Aedes aegypti and Anopheles gambiae

    PubMed Central

    Hickner, Paul V.; deBruyn, Becky; Lovin, Diane D.; Mori, Akio; Behura, Susanta K.; Pinger, Robert; Severson, David W.

    2010-01-01

    Background Mosquitoes in the Culex pipiens complex are among the most medically important vectors for human disease worldwide and include major vectors for lymphatic filariasis and West Nile virus transmission. However, detailed genetic studies in the complex are limited by the number of genetic markers available. Here, we describe methods for the rapid and efficient identification and development of single locus, highly polymorphic microsatellite markers for Cx. pipiens complex mosquitoes via in silico screening of the Cx. quinquefasciatus genome sequence. Methodology/Principal Findings Six lab colonies representing four Cx. pipiens and two Cx. quinquefasciatus populations were utilized for preliminary assessment of 38 putative loci identified within 16 Cx. quinquefasciatus supercontig assemblies (CpipJ1) containing previously mapped genetic marker sequences. We identified and validated 12 new microsatellite markers distributed across all three linkage groups that amplify consistently among strains representing the complex. We also developed four groups of 3–5 microsatellite loci each for multiplex-ready PCR. Field collections from three cities in Indiana were used to assess the multiplex groups for their application to natural populations. All were highly polymorphic (Mean  = 13.0 alleles) per locus and reflected high polymorphism information content (PIC) (Mean  = 0.701). Pairwise FST indicated population structuring between Terre Haute and Fort Wayne and between Terre Haute and Indianapolis, but not between Fort Wayne and Indianapolis. In addition, we performed whole genome comparisons of microsatellite motifs and abundance between Cx. quinquefasciatus and the primary vectors for dengue virus and malaria parasites, Aedes aegypti and Anopheles gambiae, respectively. Conclusions/Significance We demonstrate a systematic approach for isolation and validation of microsatellites for the Cx. pipiens complex by direct screen of the Cx. quinquefasciatus genome

  4. Impact of application site on the efficacy of two topically-applied insecticides to Culex quinquefasciatus Say

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ultra-low volume and low volume insecticide treatments commonly used to control mosquito populations were evaluated for efficacy against Culex quinquefasciatus using a topical bioassay technique. Traditional topical bioassays focus pesticide application to the mesothoracic pleural area. Although, in...

  5. The Native Wolbachia Endosymbionts of Drosophila melanogaster and Culex quinquefasciatus Increase Host Resistance to West Nile Virus Infection

    PubMed Central

    Glaser, Robert L.; Meola, Mark A.

    2010-01-01

    Background The bacterial endosymbiont Wolbachia pipientis has been shown to increase host resistance to viral infection in native Drosophila hosts and in the normally Wolbachia-free heterologous host Aedes aegypti when infected by Wolbachia from Drosophila melanogaster or Aedes albopictus. Wolbachia infection has not yet been demonstrated to increase viral resistance in a native Wolbachia-mosquito host system. Methodology/Principal Findings In this study, we investigated Wolbachia-induced resistance to West Nile virus (WNV; Flaviviridae) by measuring infection susceptibility in Wolbachia-infected and Wolbachia-free D. melanogaster and Culex quinquefasciatus, a natural mosquito vector of WNV. Wolbachia infection of D. melanogaster induces strong resistance to WNV infection. Wolbachia-infected flies had a 500-fold higher ID50 for WNV and produced 100,000-fold lower virus titers compared to flies lacking Wolbachia. The resistance phenotype was transmitted as a maternal, cytoplasmic factor and was fully reverted in flies cured of Wolbachia. Wolbachia infection had much less effect on the susceptibility of D. melanogaster to Chikungunya (Togaviridae) and La Crosse (Bunyaviridae) viruses. Wolbachia also induces resistance to WNV infection in Cx. quinquefasciatus. While Wolbachia had no effect on the overall rate of peroral infection by WNV, Wolbachia-infected mosquitoes produced lower virus titers and had 2 to 3-fold lower rates of virus transmission compared to mosquitoes lacking Wolbachia. Conclusions/Significance This is the first demonstration that Wolbachia can increase resistance to arbovirus infection resulting in decreased virus transmission in a native Wolbachia-mosquito system. The results suggest that Wolbachia reduces vector competence in Cx. quinquefasciatus, and potentially in other Wolbachia-infected mosquito vectors. PMID:20700535

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Identification of Blood Meal Sources in Aedes vexans and Culex quinquefasciatus in Bernalillo County, New Mexico

    PubMed Central

    Greenberg, Jacob A.; Lujan, Daniel A.; DiMenna, Mark A.; Wearing, Helen J.; Hofkin, Bruce V.

    2013-01-01

    Culex quinquefasciatus Say (Diptera: Culicidae) and Aedes vexans Meigen are two of the most abundant mosquitoes in Bernalillo County, New Mexico, USA. In this study, a polymerase chain reaction based methodology was used to identify the sources of blood meals taken by these two species. Ae. vexans was found to take a large proportion of its meals from mammals. Although less specific in terms of its blood meal preferences, Cx. quinquefasciatus was found to feed more commonly on birds. The results for Ae. vexans are similar to those reported for this species in other parts of their geographic range. Cx. quinquefasciatus appears to be more variable in terms of its host feeding under different environmental or seasonal circumstances. The implications of these results for arbovirus transmission are discussed. PMID:24224615

  8. Protein hydrolysates and associated bacterial contaminants as oviposition attractants for the mosquito Culex quinquefasciatus.

    PubMed

    Beehler, J W; Millar, J G; Mulla, M S

    1994-10-01

    Six protein or protein hydrolysate solutions were tested for activity as attractants for ovipositing Culex quinquefasciatus mosquitoes in the laboratory. Four of these solutions (egg albumin, lactalbumin hydrolysate, casein hydrolysate and yeast hydrolysate) were attractive to ovipositing females at varying concentrations, when compared to distilled water controls. Soy hydrolysate was repellent at 1%, but not significantly attractive or repellent at lower concentrations. 'Nulure', a tephritid fly bait containing protein hydrolysate, also had no significant effect on oviposition behaviour. Gravid females mostly oviposited within the first 4 h of the scotophase, regardless of the presence or absence of an oviposition attractant. Lactalbumin hydrolysate 1% solution, with or without 0.1% neomycin antibiotic, was attractive to Cx quinquefasciatus. This effect was reduced by the presence of neomycin which, alone, had no effect on oviposition. Hence both lactalbumin hydrolysate and bacterial contaminants were shown to be attractive to gravid Cx quinquefasciatus.

  9. Insecticide resistance in Culex quinquefasciatus from Zanzibar: implications for vector control programmes

    PubMed Central

    2012-01-01

    Background Zanzibar has a long history of lymphatic filariasis (LF) caused by the filarial parasite Wuchereria bancrofti, and transmitted by the mosquito Culex quinquefasciatus Say. The LF Programme in Zanzibar has successfully implemented mass drug administration (MDA) to interrupt transmission, and is now in the elimination phase. Monitoring infections in mosquitoes, and assessing the potential role of interventions such as vector control, is important in case the disease re-emerges as a public health problem. Here, we examine Culex mosquito species from the two main islands to detect W. bancrofti infection and to determine levels of susceptibility to the insecticides used for vector control. Methods Culex mosquitoes collected during routine catches in Vitongoji, Pemba Island, and Makadara, Unguja Island were tested for W. bancrofti infection using PCR. Insecticide bioassays on Culex mosquitoes were performed to determine susceptibility to permethrin, deltamethrin, lambda-cyhalothrin, DDT and bendiocarb. Additional synergism assays with piperonyl butoxide (PBO) were used for lambda-cyhalothrin. Pyrosequencing was used to determine the kdr genotype and sequencing of the mitochondrial cytochrome oxidase I (mtCOI) subunit performed to identify ambiguous Culex species. Results None of the wild-caught Culex mosquitoes analysed were found to be positive for W. bancrofti. High frequencies of resistance to all insecticides were found in Wete, Pemba Island, whereas Culex from the nearby site of Tibirinzi (Pemba) and in Kilimani, Unguja Island remained relatively susceptible. Species identification confirmed that mosquitoes from Wete were Culex quinquefasciatus. The majority of the Culex collected from Tibirinzi and all from Kilimani could not be identified to species by molecular assays. Two alternative kdr alleles, both resulting in a L1014F substitution were detected in Cx. quinquefasciatus from Wete with no homozygote susceptible detected. Metabolic resistance to

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

    PubMed

    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.

  11. Enhancing genome investigations in the mosquito Culex quinquefasciatus via BAC library construction and characterization

    PubMed Central

    2011-01-01

    Background Culex quinquefasciatus (Say) is a major species in the Culex pipiens complex and an important vector for several human pathogens including West Nile virus and parasitic filarial nematodes causing lymphatic filariasis. It is common throughout tropical and subtropical regions and is among the most geographically widespread mosquito species. Although the complete genome sequence is now available, additional genomic tools are needed to improve the sequence assembly. Findings We constructed a bacterial artificial chromosome (BAC) library using the pIndigoBAC536 vector and HindIII partially digested DNA isolated from Cx. quinquefasciatus pupae, Johannesburg strain (NDJ). Insert size was estimated by NotI digestion and pulsed-field gel electrophoresis of 82 randomly selected clones. To estimate genome coverage, each 384-well plate was pooled for screening with 29 simple sequence repeat (SSR) and five gene markers. The NDJ library consists of 55,296 clones arrayed in 144 384-well microplates. Fragment insert size ranged from 50 to 190 kb in length (mean = 106 kb). Based on a mean insert size of 106 kb and a genome size of 579 Mbp, the BAC library provides ~10.1-fold coverage of the Cx. quinquefasciatus genome. PCR screening of BAC DNA plate pools for SSR loci from the genetic linkage map and for four genes associated with reproductive diapause in Culex pipiens resulted in a mean of 9.0 positive plate pools per locus. Conclusion The NDJ library represents an excellent resource for genome assembly enhancement and characterization in Culex pipiens complex mosquitoes. PMID:21914202

  12. Bioefficacy of essential oil from Polygonum hydropiper L. against mosquitoes, Anopheles stephensi and Culex quinquefasciatus.

    PubMed

    Maheswaran, Rajan; Ignacimuthu, Savarimuthu

    2013-11-01

    The biological activity of essential oil extracted from the leaves of Polygonum hydropiper and a compound, confertifolin, isolated from this plant was bioassayed against larva of mosquitoes, Anopheles stephensi and Culex quinquefasciatus. The essential oil showed the LC50 values of 189 and 243ppm; 217 and 242ppm, confertifolin (6,6,9a-trimethyl-4,5,5a,6,7,8,9,9a-octahydronaphtho[1,2-c]furan-3(1H)-one) showed the LC50 values of 2.40 and 3.09ppm; 4.07 and 4.18ppm against the second and fourth instar larvae of An. stephensi and Cx. quinquefasciatus, respectively. At 10ppm confertifolin showed ovicidal activity of 100, 98.6 and 86.4% against An. stephensi and 100, 100 and 75.2% against Cx. quinquefasciatus on 0-6, 6-12 and 12-18h old eggs; the repellent activity persisted for 314.6 and 319.0min; oviposition deterrent activity was 97.2 and 99% and adulticidal activity was 100 and 100% against An. stephensi and Cx. quinquefasciatus, respectively. The results were statistically significant. Confertifolin could be considered for use in the control of human vector mosquitoes. PMID:23942240

  13. Determination of homozygous susceptible strain in Culex quinquefasciatus (Say), using single raft sib-selection method.

    PubMed

    Hidayati, H; Nazni, W A; Mohd, S A

    2008-04-01

    The standard laboratory strain was found to be heterozygous for susceptibility. Hence, an attempt was made to obtain a homozygous susceptible strain in Culex quinquefasciatus (Say) using single raft sib-selection method. Lab-bred females of Cx. quinquefasciatus from insectariums, Unit of Medical Entomology were used in the experiment. After blood feeding Cx. quinquefasciatus mosquitoes laid eggs in raft form, ten rafts selected randomly for the test. Each egg raft was introduced into a plastic tray from number one to number ten. Twenty-five third stage larvae from each tray were exposed to 17.5 microl from 500mg/l malathion in a paper cup label number 1 to number ten. In the bioassay, which had 100% mortality, the respective larva in that particular tray was bred to adult stage for the following generation. Less than 7days old female mosquitoes that emerged from F(0) were used in the test. The F(0) and the subsequent adult and larval stage generations were subjected to adult and larval bioassay. After selection for about 10 generations, a homozygous susceptible strain in Cx. quinquefasciatus was obtained.

  14. Differential protein expression in the midgut of Culex quinquefasciatus mosquitoes induced by the insecticide temephos.

    PubMed

    Games, P D; Alves, S N; Katz, B B; Tomich, J M; Serrão, J E

    2016-09-01

    Mosquitoes are vectors for pathogens of malaria, lymphatic filariasis, dengue, chikungunya, yellow fever and Japanese encephalitis. Culex quinquefasciatus Say, 1823 (Diptera: Culicidae) is a known vector of lymphatic filariasis. Its control in Brazil has been managed using the organophosphate temephos. Studies examining the proteins of Cx. quinquefasciatus that are differentially expressed in response to temephos further understanding of the modes of action of the insecticide and may potentially identify resistance factors in the mosquito. In the present study, a comparative proteomic analysis, using 2-dimensional electrophoresis coupled with matrix-assisted laser desorption/ionization (MALDI) time of flight (TOF)/TOF mass spectrometry, and bioinformatics analyses were performed to identify midgut proteins in Cx. quinquefasciatus larvae that were differentially expressed in response to exposure to temephos relative to those in untreated controls. A total of 91 protein spots were differentially expressed; 40 were upregulated and 51 were downregulated by temephos. A total of 22 proteins, predominantly upregulated, were identified as known to play a role in the immune response, whereas the downregulated proteins were involved in energy and protein catabolism. This is the first proteome study of the midgut of Cx. quinquefasciatus and it provides insights into the molecular mechanisms of insecticide-induced responses in the mosquito.

  15. Bioefficacy of essential oil from Polygonum hydropiper L. against mosquitoes, Anopheles stephensi and Culex quinquefasciatus.

    PubMed

    Maheswaran, Rajan; Ignacimuthu, Savarimuthu

    2013-11-01

    The biological activity of essential oil extracted from the leaves of Polygonum hydropiper and a compound, confertifolin, isolated from this plant was bioassayed against larva of mosquitoes, Anopheles stephensi and Culex quinquefasciatus. The essential oil showed the LC50 values of 189 and 243ppm; 217 and 242ppm, confertifolin (6,6,9a-trimethyl-4,5,5a,6,7,8,9,9a-octahydronaphtho[1,2-c]furan-3(1H)-one) showed the LC50 values of 2.40 and 3.09ppm; 4.07 and 4.18ppm against the second and fourth instar larvae of An. stephensi and Cx. quinquefasciatus, respectively. At 10ppm confertifolin showed ovicidal activity of 100, 98.6 and 86.4% against An. stephensi and 100, 100 and 75.2% against Cx. quinquefasciatus on 0-6, 6-12 and 12-18h old eggs; the repellent activity persisted for 314.6 and 319.0min; oviposition deterrent activity was 97.2 and 99% and adulticidal activity was 100 and 100% against An. stephensi and Cx. quinquefasciatus, respectively. The results were statistically significant. Confertifolin could be considered for use in the control of human vector mosquitoes.

  16. Genetic Variations in Bionomics of Culex quinquefasciatus (Diptera: Culicidae) Mosquito Population in Minna, North Central Nigeria.

    PubMed

    Ukubuiwe, Azubuike C; Olayemi, Israel K; Jibrin, Aisha I

    2016-01-01

    The need to have an improved knowledge on the bioecology of Culex quinquefasciatus, a prerequisite in the development of cost-effective control strategies, has informed the present preliminary investigation to put in better perspective variations that exist in the egg rafts of the species. Freshly laid egg rafts were collected and incubated at ambient temperature in well-labeled plastic trays. The results showed overall inconsistency in all indices monitored for the egg rafts. Generally, survivorship was high for the species. All immature stage and adult parameters measured varied significantly among the egg rafts and between/within sexes of the species. Therefore, this study suggests the presence of inherent variation in the bionomics of egg rafts of C. quinquefasciatus, probably influenced by the environment and hence underscores the need for additional studies to further elucidate the roles of genetics and environment in vectorial competence of the species, in order to develop robust sustainable mosquito vector control protocols.

  17. Genetic Variations in Bionomics of Culex quinquefasciatus (Diptera: Culicidae) Mosquito Population in Minna, North Central Nigeria

    PubMed Central

    Ukubuiwe, Azubuike C.; Olayemi, Israel K.; Jibrin, Aisha I.

    2016-01-01

    The need to have an improved knowledge on the bioecology of Culex quinquefasciatus, a prerequisite in the development of cost-effective control strategies, has informed the present preliminary investigation to put in better perspective variations that exist in the egg rafts of the species. Freshly laid egg rafts were collected and incubated at ambient temperature in well-labeled plastic trays. The results showed overall inconsistency in all indices monitored for the egg rafts. Generally, survivorship was high for the species. All immature stage and adult parameters measured varied significantly among the egg rafts and between/within sexes of the species. Therefore, this study suggests the presence of inherent variation in the bionomics of egg rafts of C. quinquefasciatus, probably influenced by the environment and hence underscores the need for additional studies to further elucidate the roles of genetics and environment in vectorial competence of the species, in order to develop robust sustainable mosquito vector control protocols. PMID:27013900

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

    PubMed

    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.

  19. Larval development of Culex quinquefasciatus in water with low to moderate.

    PubMed

    Noori, Navideh; Lockaby, B Graeme; Kalin, Latif

    2015-12-01

    Population growth and urbanization have increased the potential habitats, and consequently the abundance of Culex quinquefasciatus, the southern house mosquito, a vector of West Nile Virus in urban areas. Water quality is critical in larval habitat distribution and in providing microbial food resources for larvae. A mesocosm experiment was designed to demonstrate which specific components of water chemistry are conducive to larval Culex mosquitoes. Dose-response relationships between larval development and NO3 , NH4 , and PO4 concentrations in stream water were developed through this experiment to describe the isolated effects of each nutrient on pre-adult development. The emergence pattern of Culex mosquitoes was found to be strongly related to certain nutrients, and results showed that breeding sites with higher PO4 or NO3 concentrations had higher larval survival rates. High NO3 concentrations favor the development of male mosquitoes and suppress the development of female mosquitoes, but those adult females that do emerge develop faster in containers with high NO3 levels compared to the reference group. The addition of PO4 in the absence of nitrogen sources to the larval habitat slowed larval development, however, it took fewer days for larvae to reach the pupal stage in containers with combinations of NO3 and PO4 or NH4 and PO4 nutrients. Results from this study may bolster efforts to control WNV in urban landscapes by exploring water quality conditions of Culex larval habitats that produce adult mosquitoes. PMID:26611953

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

    PubMed Central

    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

  1. Development of permethrin resistance in Culex quinquefasciatus Say in Kuala Lumpur, Malaysia.

    PubMed

    Wan-Norafikah, Othman; Nazni, Wasi Ahmad; Lee, Han Lim; Zainol-Ariffin, Pawanchee; Sofian-Azirun, Mohd

    2013-07-01

    The resistance status towards permethrin among the laboratory strain, the permethrin-selected strain and four field strains of Culex quinquefasciatus collected in Kuala Lumpur, Malaysia was determined using three standard laboratory methods: WHO larval bioassay, WHO adult bioassay and biochemical microplate assay. Cx. quinquefasciatus permethrin-selected strain larvae were the least susceptible to permethrin with a resistance ratio of 47.28-folds, whereas all field strain larvae of the same species were tolerant to permethrin with resistance ratios of more than 3-folds. In contrast, in adult stage, the permethrin exposed permethrin-selected strain (resistance ratio = 1.27) was found to be more susceptible to permethrin than all permethrin-exposed field strains (resistance ratios = 2.23-2.48). Complete mortalities for all strains of Cx. quinquefasciatus adults proved the effectiveness of the synergist; piperonyl butoxide (PBO). For the biochemical microplate assay, the reduction of the mean optical density of elevated oxidase activity of three field strains upon exposure to PBO confirmed the association between oxidase activity and permethrin tolerance. On the other hand, irregular patterns of the mean optical density of elevated oxidase activity in the laboratory strain, permethrin-selected strain and Jalan Fletcher strain illustrated the gene variation within these mosquito colonies as well as the involvement of other enzyme activities in the permethrin resistance occurred.

  2. Larvicidal efficacy of medicinal plant extracts against Anopheles stephensi and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Kamaraj, C; Abdul Rahman, A; Bagavan, A; Abduz Zahir, A; Elango, G; Kandan, P; Rajakumar, G; Marimuthu, S; Santhoshkumar, T

    2010-08-01

    Mosquitoes transmit serious human diseases, causing millions of deaths every year. Natural products of plant origin with insecticidal properties have been used in recent years for control of a variety of pest insects and vectors. The present study was based on assessments of the larvicidal activity to determine the efficacies of hexane, chloroform, ethyl acetate, acetone and methanol extracts of ten medicinal plants tested against fourth instar larvae of malaria vector, Anopheles stephensi Liston and lymphatic filariasis vector, Culex quinquefasciatus Say (Diptera: Culicidae). The larvicidal activity was assessed by the procedure of WHO with some modification. The highest larval mortality was found in leaf acetone of Adhatoda vasica, bark ethyl acetate of Annona squamosa, methanol leaf and flower of Cassia auriculata, leaf ethyl acetate of Hydrocotyle javanica, methanol leaf and seed of Solanum torvum and leaf hexane extracts of Vitex negundo against the fourth instar larvae of An. stephensi and Cx. quinquefasciatus. The calculated LC90 for acetone, ethyl acetate, methanol and hexane extracts of dried leaf and bark of A. vasica, A. squamosa, S. torvum, and V. negundo were in the range of 70.38-210.68 ppm. Our results suggest that the leaf methanol extract of S.torvum and bark ethyl acetate extract of A. squamosa from Southern India have the potential for use to control mosquitoes. Therefore, this study provides the larvicidal activity against An. stephensi and Cx. quinquefasciatus of plant extracts. PMID:20962718

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

    PubMed

    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.

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

    PubMed

    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.

  5. Occurrence and phylogenetic characterization of a baculovirus isolated from Culex quinquefasciatus in São Paulo State, Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this study was to assess the occurrence of baculovirus infections in mosquitoes and characterize them by using molecular tools. Fortnightly collections were made of mosquito larvae in the city of Caraguatatuba. Six larvae of Culex quinquefasciatus were isolated that had white cysts (nodul...

  6. Bagaza virus inhibits Japanese encephalitis & West Nile virus replication in Culex tritaeniorhynchus & Cx. quinquefasciatus mosquitoes

    PubMed Central

    Sudeep, A.B.; Bondre, V.P.; George, R.; Ghodke, Y.S.; Aher, R.V.; Gokhale, M.D.

    2015-01-01

    Background & objectives: Studies have shown that certain flaviviruses influence susceptibility of mosquitoes by inhibiting/enhancing replication of important flaviviruses. Hence, a study was designed to determine whether Bagaza virus (BAGV), a flavivirus isolated from Culex tritaeniorhynchus mosquitoes in India, alters susceptibility of Cx. tritaeniorhynchus and Cx. quinquefasciatus mosquitoes to Japanese encephalitis (JEV) and West Nile viruses (WNV). Methods: JEV and WNV infection in Cx. tritaeniorhynchus and Cx. quinquefasciatus mosquitoes in the presence of BAGV was carried out by intrathoracic (IT) inoculation and oral feeding methods. Mosquitoes were infected with BAGV and WNV/JEV either simultaneously or in a phased manner, in which mosquitoes were infected with BAGV by IT inoculation followed by super-infection with JEV/WNV after eight days post-infection (PI). JEV and WNV yield on 7th and 14th day PI after super-infection was determined by 50 per cent tissue culture infective dose (TCID50) method. Results: In Cx. tritaeniorhynchus mosquitoes, prior infection with BAGV significantly reduced JEV and WNV replication while in Cx. quinquefasciatus, BAGV influence was only seen with WNV. Reduction in virus titre was observed in IT inoculated and oral fed mosquitoes irrespective of the infection mode. JEV replication was also found reduced in Cx. tritaeniorhynchus mosquitoes persistently infected with BAGV at passage four. Interpretation & conclusions: BAGV infection in Cx. tritaeniorhynchus and Cx. quinquefasciatus mosquitoes altered their susceptibility to JEV and WNV producing low virus yield. However, the role of BAGV in inhibiting JEV/WNV replication in field mosquitoes needs further investigations. PMID:26905241

  7. Vector Competence of Culex neavei and Culex quinquefasciatus (Diptera: Culicidae) from Senegal for Lineages 1, 2, Koutango and a Putative New Lineage of West Nile virus

    PubMed Central

    Fall, Gamou; Diallo, Mawlouth; Loucoubar, Cheikh; Faye, Ousmane; Sall, Amadou Alpha

    2014-01-01

    West Nile virus (WN virus) is one of the most widespread arbovirus and exhibits a great genetic diversity with 8 lineages, at least 4 (1, 2, Koutango, and putative new) are present in Africa. In West Africa, Culex neavei and Culex quinquefasciatus are considered as potential vectors for WN virus transmission in sylvatic or urban context. We analyzed the vector competence of these Culex species from Senegal for African lineages and envelope proteins sequences of viral strains used. We showed that lineage 1 is transmitted by both Culex mosquitoes, whereas the putative new lineage 8 is transmitted only by Cx. neavei. Our findings suggest that genetic variability can affect vector competence and depend on mosquito. However, when considering the infective life rate, the mosquito population seems to be inefficient for WN virus transmission in the field and could explain the low impact of WN virus in Africa. PMID:24567319

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

    PubMed

    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.

  9. Larvicidal and Histopathological Effects of Cassia siamea Leaf Extract against Culex quinquefasciatus

    PubMed Central

    Jiraungkoorskul, Kanitta; Jiraungkoorskul, Wannee

    2015-01-01

    A traditional Thai medicinal extract from Cassia siamea was evaluated with respect to its larvicidal properties by determining the median lethal concentration (LC50) at 24, 48, 72 and 96 h against the fourth instar larvae of Culex quinquefasciatus, which is a carrier of mosquito-borne diseases, by studying the histopathological alterations. The 24, 48, 72 and 96 h LC50 values were 394.29, 350.24, 319.17 and 272.42 ppm, respectively. The histopathological lesions after exposure to 25% of the 24-h LC50 were observed primarily in the midgut of the larva. Lesions with edema, swelling, and deformation or elongation of the epithelial cells were observed. Moreover, cells protruding into the lumen and absent microvilli were also found in some areas. The present study reveals that aqueous C. siamea leaf extracts have natural biopesticide properties. PMID:26868707

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

    PubMed

    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. PMID:23427662

  11. Associative learning of odor with food- or blood-meal by Culex quinquefasciatus Say (Diptera: Culicidae)

    NASA Astrophysics Data System (ADS)

    Tomberlin, Jeffery K.; Rains, Glen C.; Allan, Sandy A.; Sanford, Michelle R.; Lewis, W. Joe

    2006-11-01

    The ability of many insects to learn has been documented. However, a limited number of studies examining associative learning in medically important arthropods has been published. Investigations into the associative learning capabilities of Culex quinquefasciatus Say were conducted by adapting methods commonly used in experiments involving Hymenoptera. Male and female mosquitoes were able to learn a conditioned stimulus that consisted of an odor not normally encountered in nature (synthetic strawberry or vanilla extracts) in association with an unconditioned stimulus consisting of either a sugar (males and females) or blood (females) meal. Such information could lead to a better understanding of the ability of mosquitoes to locate and select host and food resources in nature.

  12. Insecticides resistance in the Culex quinquefasciatus populations from northern Thailand and possible resistance mechanisms.

    PubMed

    Yanola, Jintana; Chamnanya, Saowanee; Lumjuan, Nongkran; Somboon, Pradya

    2015-09-01

    The mosquito vector Culex quinquefasciatus is known to be resistant to insecticides worldwide, including Thailand. This study was the first investigation of the insecticide resistance mechanisms, involving metabolic detoxification and target site insensitivity in C. quinquefasciatus from Thailand. Adult females reared from field-caught larvae from six provinces of northern Thailand were determined for resistant status by exposing to 0.05% deltamethrin, 0.75% permethrin and 5% malathion papers using the standard WHO susceptibility test. The overall mortality rates were 45.8%, 11.4% and 80.2%, respectively. A fragment of voltage-gated sodium channel gene was amplified and sequenced to identify the knock down resistance (kdr) mutation. The ace-1 gene mutation was determined by using PCR-RFLP. The L1014F kdr mutation was observed in all populations, but the homozygous mutant F/F1014 genotype was found only in two of the six provinces where the kdr mutation was significantly correlated with deltamethrin resistance. However, none of mosquitoes had the G119S mutation in the ace-1 gene. A laboratory deltamethrin resistant strain, Cq_CM_R, has been established showing a highly resistant level after selection for a few generations. The mutant F1014 allele frequency was significantly increased after one generation of selection. A synergist assay was performed to assess the metabolic detoxifying enzymes. Addition of bis(4-nitrophenyl)-phosphate (BNPP) and diethyl maleate (DEM), inhibitors of esterases and glutathione S-transferases (GST), respectively, into the larval bioassay of the Cq_CM strain with deltamethrin showed no significant reduction. By contrast, addition of piperonyl butoxide (PBO), an inhibitor of cytochrome P450 monooxygenases, showed a 9-fold reduction of resistance. Resistance to pyrethroids in C. quinquefasciatus is widely distributed in northern Thailand. This study reports for the first time for the detection of the L1014F kdr mutation in wild populations

  13. Insecticidal and genotoxic activity of Psoralea corylifolia Linn. (Fabaceae) against Culex quinquefasciatus Say, 1823

    PubMed Central

    2013-01-01

    Background 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. Methods 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. Results 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%). Conclusion 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. PMID:23379981

  14. Culex quinquefasciatus larval microbiomes vary with instar and exposure to common wastewater contaminants

    PubMed Central

    Pennington, Marcus J.; Prager, Sean M.; Walton, William E.; Trumble, John T.

    2016-01-01

    Like many insects, mosquitoes, rely on endosymbionts to grow and develop. These can be acquired from the environment. We used next generation 454 pyrosequencing to discern the whole-body microbiome of the mosquito species Culex quinquefasciatus in various larval stadia and following exposure to common pharmaceutical and personal care products (PPCPs) found in wastewater. PPCP treatments included environmentally-relevant concentrations; 1) a combination of common antibiotics, 2) a combination of mammalian hormones, 3) a mixture of the antibiotic and hormone treatments plus acetaminophen and caffeine and, 4) an untreated control. Within control groups, the predominant families of bacterial symbionts change with each larval instar despite consistent diets and rearing conditions. This trend was also seen in hormone treatments but not in the antibiotic or the mixture treatments. Richness and evenness were reduced in both antibiotic and mixture treatments, suggesting that antibiotics remove certain bacteria or inhibit them from increasing to proportions seen in the control treatment. Interestingly, the mixture treatments had greater richness and evenness compared to antibiotic alone treatments, possibly due to the other contaminants facilitating growth of different bacteria. These findings illuminate the complexity of the microbiome of C. quinquefasciatus and may have implications for more effective control strategies. PMID:26912375

  15. Host-Feeding Preference of the Mosquito, Culex quinquefasciatus, in Yucatan State, Mexico

    PubMed Central

    Garcia-Rejon, Julian E.; Blitvich, Bradley J.; Farfan-Ale, Jose A.; Loroño-Pino, Maria A.; Chi Chim, Wilberth A.; Flores-Flores, Luis F.; Rosado-Paredes, Elsy; Baak-Baak, Carlos; Perez-Mutul, Jose; Suarez-Solis, Victor; Fernandez-Salas, Ildefonso; Beaty, Barry J.

    2010-01-01

    Studies were conducted to determine the host-feeding preference of Culex quinquefasciatus Say (Diptera: Culicidae) in relation to the availability of human and domestic animals in the city of Merida, Yucatan State, Mexico. Mosquitoes were collected in the backyards of houses using resting wooden boxes. Collections were made five times per week from January to December 2005. DNA was extracted from engorged females and tested by PCR using universal avian- and mammalian-specific primers. DNA extracted from avian-derived blood was further analyzed by PCR using primers that differentiate among the birds of three avian orders: Passeriformes, Columbiformes and Galliformes. PCR products obtained from mammalian-derived blood were subjected to restriction enzyme digestion to differentiate between human-, dog-, cat-, pig-, and horse-derived blood meals. Overall, 82% of engorged mosquitoes had fed on birds, and 18% had fed on mammals. The most frequent vertebrate hosts were Galliformes (47.1%), Passeriformes (23.8%), Columbiformes (11.2%) birds, and dogs (8.8%). The overall human blood index was 6.7%. The overall forage ratio for humans was 0.1, indicating that humans were not a preferred host for Cx. quinquefasciatus in Merida. PMID:20578953

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

    PubMed

    Barbosa, Rosângela M R; Souto, Antonio; Eiras, Alvaro E; Regis, Lêda

    2007-06-01

    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. PMID:17612774

  17. Resistance to organophosphorous insecticides in Culex pipiens quinquefasciatus (Diptera: Culicidae) from Martinique.

    PubMed

    Yébakima, A; Raymond, M; Marquine, M; Pasteur, N

    1995-03-01

    Before beginning a widespread control program against Culex pipiens quinquefasciatus in Martinique, resistance to temephos, chlorpyrifos, and two organophosphorous insecticides, was investigated at seven breeding sites. At LC95, populations exhibited resistance ratios between 6.9 and 11.6 for temephos and between 6.4 and 51.4 for chlorpyrifos. Overproduced esterases A2-B2 and B1, known to be involved in organophosphorous-resistance, were present at all breeding sites; esterases A2-B2 frequency was > 50% at all sites but one; and esterase B1 frequency was < 7%. Experimental treatment of three breeding sites with temephos induced no significant increase in resistance, but our esterase studies indicated a significant increase in the frequencies of esterase B1 and of a new highly active esterase C2. These results indicate that a large-scale C. p. quinquefasciatus control program with organophosphorous insecticides will induce a rapid increase of these resistance genes throughout Martinique. However, this may not necessarily result in high levels of resistance, because, at present, the level of gene amplification of esterase B still appears to be low.

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

    PubMed

    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.

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

    PubMed

    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.

  20. The effects of spinosad on Culex quinquefasciatus and three nontarget insect species.

    PubMed

    Jones, Owen M; Ottea, James

    2013-12-01

    Spinosad is a relatively new insecticide with a unique mode of action that is being evaluated for control of larval mosquitoes. Whereas a number of toxicological studies have measured effects of spinosad on various animals, few have been conducted on the effects of spinosad on nontarget, aquatic insect species. Such studies are important as these species might be found in the same environments as mosquito larvae targeted for control. A neighborhood pond was surveyed to find a representative species of mosquito as well as other common aquatic insects with which to examine susceptibility to spinosad and nontarget effects. The mosquito species chosen was Culex quinquefasciatus and the most common nontarget taxa were immature stages of a mayfly (Caenis sp., Ephemeroptera: Caenidae), a damselfly (Ischnura sp., Odonata: Coenagrionidae), and a dragonfly (Pachydiplax longipennis, Odonata: Libellulidae). Bioassays of mosquitoes from a reference susceptible strain (Sebring-S) and field collections of Cx. quinquefasciatus were used to determine susceptibility to spinosad. In addition, susceptibility was examined in nontarget taxa using spinosad concentrations corresponding to the LC50 of field-collected mosquitoes (0.031 ppm) and the maximum label rate (1.6 ppm) of spinosad (Natular EC). Susceptibility to spinosad did not differ between Sebring-S and field-collected mosquitoes. However, there was a marked difference in susceptibility among nontarget taxa. Susceptibility was greatest in Caenis sp., followed by Ischnura sp., and then P. longipennis. PMID:24551967

  1. West Nile Virus Vector Competency of Culex quinquefasciatus Mosquitoes in the Galápagos Islands

    PubMed Central

    Eastwood, Gillian; Kramer, Laura D.; Goodman, Simon J.; Cunningham, Andrew A.

    2011-01-01

    The mosquito-transmitted pathogen West Nile virus (WNV) is not yet present in the Galápagos Archipelago of Ecuador. However, concern exists for fragile endemic island fauna after population decreases in several North American bird species and pathology in certain reptiles. We examined WNV vector competency of a Galápagos strain of mosquito (Culex quinquefasciatus Say). Field specimens were tested for their capacity to transmit the WN02-1956 strain of WNV after incubation at 27°C or 30°C. Rates of infection, dissemination, and transmission all increased with days post-exposure to WNV, and the highest rates were observed at 28 days. Infection rates peaked at 59% and transmission rates peaked at 44% (of mosquitoes tested). Vector efficiency increased after day 14. Rates of infection but not of transmission were significantly influence by temperature. No vertical transmission was detectable. We demonstrate that Galápagos Cx. quinquefasciatus are competent WNV vectors, and therefore should be considered an animal and public health risk for the islands and controlled wherever possible. PMID:21896799

  2. Control of Culex quinquefasciatus in pit latrines, using shredded, waste polystyrene.

    PubMed

    Nathan, M B; Toney, S; Bramble, S; Reid, V

    1996-04-01

    As an alternative to the use of commercially available, expanded-polystyrene beads, a study was made of the effectiveness of shredded, waste polystyrene (SWAP) for the control of Culex quinquefasciatus. The relevant physical properties of the SWAP were first investigated in the laboratory. Then, under field conditions in wet pit latrines, mosquito emergence rates were measured before and after application of the material. In the laboratory, when compared with the commercial product, the irregular shape of the SWAP particles greatly reduced their capacity to spread over the water surface and the interstitial air spaces also permitted respiration and development of mosquito larvae. Nevertheless, under field conditions, with careful application of the SWAP over the water surfaces in wet pit latrines, almost complete control of mosquito breeding was observed within a few days. This was sustained for 60 days, at which time observations were discontinued. SWAP appears to offer an effective, cheap and readily available alternative to the commercial product for the control of C. quinquefasciatus. The practicality of using it in community-based, mosquito-control programmes warrants further study. PMID:8762412

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

    PubMed Central

    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

  4. Purification and properties of an esterase from organophosphate-resistant strain of the mosquito Culex quinquefasciatus.

    PubMed Central

    Merryweather, A T; Crampton, J M; Townson, H

    1990-01-01

    Organophosphate-resistant and -susceptible strains of Culex quinquefasciatus (mosquito) have been compared on the basis of their esterase activities. The homozygous resistant strain (Dar) shows two highly active esterases after starch-gel electrophoresis, of Rm 0.2 and 0.4, which are absent from susceptible strains (Apo, Mon), and which previous selection studies have shown to be inseparable from organophosphate resistance. After SDS/polyacrylamide-gel electrophoresis and silver staining of total C. quinquefasciatus proteins, a 62 kDa band is observed in strain Dar at high concentrations, and in susceptible strains in trace amounts. After Western blotting, this 62 kDa protein is recognized by antisera raised against the two esterases eluted from starch gels. After chromatofocusing of Dar proteins, the 62 kDa protein is seen to be associated with esterase activity, and of a similar pI to that observed for esterases after isoelectric focusing. Post-translational modification is not required for recognition of the 62 kDa putative esterase, since the protein is immunoprecipitated by the anti-esterase serum from products of translation of Dar mRNA in vitro. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 6. Fig. 7. PMID:2178604

  5. Association of esterases with insecticide resistance in Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Gordon, Jennifer R; Ottea, James

    2012-06-01

    The southern house mosquito, Culex quinquefasciatus Say, is a competent vector of human disease and an important target of mosquito abatement programs. However, these management programs have been compromised by development of insecticide resistance. In the current study, susceptibilities to naled and resmethrin, two adulticides used in mosquito abatement, were monitored using a topical and contact bioassay, respectively, in five field- collected populations of C. quinquefasciatus (MARC, HOOD1, HOOD2, MINLOVE, and THIB). Frequencies of resistance, measured as survival after treatment with discriminating concentrations (i.e., sufficient to kill > 90% of a reference susceptible strain) were high (88.0-96.8%) in all field collections treated with naled, but were variable (3.3-94.2%) with resmethrin. In addition, esterase activities in mosquitoes from these collections were quantified using alpha-naphthyl acetate and ranged from 1.08 to 3.39 micromol alpha-naphthol produced min(-1) mg prot(-1). Heightened activities were associated with decreased insecticide susceptibility in HOOD1, THIB, and MINLOVE but not HOOD2. Esterases were visualized using native polyacrylamide gel electrophoresis, and intra- and interstrain differences in banding patterns were detected. In addition, esterases from MINLOVE mosquitoes were more numerous and intensely staining when compared with those from a laboratory-susceptible strain. Finally, naled synergized the toxicity of resmethrin in populations with decreased insecticide susceptibility and increased esterase activity by 2.5-(MINLOVE) to three-fold (THIB). Results from this study will allow management strategies for populations of C. quinquefasciatus to be optimized, and provide a foundation for further studies exploring use of esterase inhibitors as synergists of pyrethroid toxicity. PMID:22812138

  6. Modeling the population dynamics of Culex quinquefasciatus (Diptera: Culcidae), along an elevational gradient in Hawaii

    USGS Publications Warehouse

    Ahumada, Jorge A.; LaPointe, Dennis; Samuel, Michael D.

    2004-01-01

    We present a population model to understand the effects of temperature and rainfall on the population dynamics of the southern house mosquito, Culex quinquefasciatus Say, along an elevational gradient in Hawaii. We use a novel approach to model the effects of temperature on population growth by dynamically incorporating developmental rate into the transition matrix, by using physiological ages of immatures instead of chronological age or stages. We also model the effects of rainfall on survival of immatures as the cumulative number of days below a certain rain threshold. Finally, we incorporate density dependence into the model as competition between immatures within breeding sites. Our model predicts the upper altitudinal distributions of Cx. quinquefasciatus on the Big Island of Hawaii for self-sustaining mosquito and migrating summer sink populations at 1,475 and 1,715 m above sea level, respectively. Our model predicts that mosquitoes at lower elevations can grow under a broader range of rainfall parameters than middle and high elevation populations. Density dependence in conjunction with the seasonal forcing imposed by temperature and rain creates cycles in the dynamics of the population that peak in the summer and early fall. The model provides a reasonable fit to the available data on mosquito abundance for the east side of Mauna Loa, Hawaii. The predictions of our model indicate the importance of abiotic conditions on mosquito dynamics and have important implications for the management of diseases transmitted by Cx. quinquefasciatus in Hawaii and elsewhere.

  7. Laboratory and field evaluation of medicinal plant extracts against filarial vector, Culex quinquefasciatus Say (Diptera: Culicidae).

    PubMed

    Kovendan, Kalimuthu; Murugan, Kadarkarai; Panneerselvam, Chellasamy; Mahesh Kumar, Palanisamy; Amerasan, Duraisamy; Subramaniam, Jayapal; Vincent, Savariar; Barnard, Donald R

    2012-06-01

    The present study explored the effects of Jatropha curcas, Hyptis suaveolens, Abutilon indicum, and Leucas aspera tested against third instar larvae of filarial vector, Culex quinquefasciatus. The dried plant materials were powdered by an electrical blender. From each sample, 500 g powder was macerated with 1.5 L of hexane, chloroform, ethyl acetate, and methanol 8h, using Soxhlet apparatus, and filtered. The extracts were concentrated at reduced temperature on a rotary evaporator and stored at a temperature of 4°C. The yield of crude extract was 11.4, 12.2, 10.6, and 13.5 g in hexane, chloroform, ethyl acetate, and methanol, respectively. The hexane, chloroform, ethyl acetate, and methanol extract of J. curcas with LC(50) values of 230.32, 212.85, 192.07, and 113.23 ppm; H. suaveolens with LC(50) values of 213.09, 217.64, 167.59, and 86.93 ppm; A. indicum with LC(50) values of 204.18, 155.53, 166.32, and 111.58 ppm; and L. aspera with LC(50) values of 152.18, 118.29, 111.43, and 107.73 ppm, respectively, against third instar larvae of C. quinquefasciatus. The larval mortality was observed after 24 h of exposure. Maximum larvicidal activity was observed in the methanolic extract followed by ethyl acetate, chloroform, and hexane extract. No mortality was observed in the control. The observed mortality were statistically significant at P < 0.05 level. L. aspera showed the highest mortality rate against the mosquito larvae in laboratory and field. The larval density was decreased after the treatment of plant extracts at the breeding sites (sewage water), and hence, these plant extracts of the suitable alternatives of synthetic insecticides for the mosquito vector management. The present results suggest that the medicinal plants extract was an excellent potential for controlling filarial vector, C. quinquefasciatus. PMID:22146997

  8. DDT and pyrethroid resistance status and laboratory evaluation of bio-efficacy of long lasting insecticide treated nets against Culex quinquefasciatus and Culex decens in Ghana.

    PubMed

    Kudom, Andreas A; Mensah, Ben A; Froeschl, Guenter; Rinder, Heinz; Boakye, Daniel

    2015-10-01

    Nuisance from Culex mosquitoes in Ghana has a serious negative impact on the standard of living in many urban communities. In addition, a perceived lack of efficacy of long lasting insecticide treated nets (LLINs) against nuisance mosquitoes contributes to their discontinued use. This again compromises malaria control, even if Anopheles species themselves would still be susceptible to the insecticides used. Control strategies involve pyrethroid insecticides but information on Culex mosquito susceptibility to these insecticides is limited. A nationwide survey was conducted to address this problem. In adults, susceptibility to permethrin, deltamethrin and DDT as well as enzyme activity and kdr mutation were determined. Cone and tunnel bioassay were also carried out to determine the efficacy of LLINs against the mosquitoes. Culex quinquefasciatus and Culex decens were identified in the study area. Higher deltamethrin and DDT resistance and relatively low permethrin resistance were observed in both species. High enzyme activities and kdr mutations were observed in C. quinquefasciatus but not in C. decens. However, reduced efficacy of LLINs was observed in both mosquito species. This adds up to the evidence of the spread of pyrethroid resistance in mosquitoes and its negative impact on control strategies.

  9. Temporal Gene Expression Profiles of Pre Blood-Fed Adult Females Immediately Following Eclosion in the Southern House Mosquito Culex quinquefasciatus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prior to acquisition of the first host blood meal, the anautogenous mosquito Culex quinquefasciatus requires a period of time in order to prepare for the blood feeding and, later, vitellogenesis. In the current study, we conducted whole transcriptome analyses of adult female Culex mosquitoes to iden...

  10. Chemical constituents and larvicidal property of the essential oil of Blumea mollis (D. Don) Merr. against Culex quinquefasciatus.

    PubMed

    Senthilkumar, Annadurai; Kannathasan, Krishnan; Venkatesalu, Venugopalan

    2008-09-01

    The essential oil from the leaves of Blumea mollis was extracted and the chemical constituents and the larvicidal against Culex quinquefasciatus effects studied. The analyses of gas chromatography (GC) and GC-mass spectroscopy (GC-MS) revealed that the leaf essential oil of B. mollis contained 39 compounds, and the major chemical compounds identified were linalool (19.43%), gamma-elemene (12.19%), copaene (10.93%), estragole (10.81%), Allo-ocimene (10.03%), gamma-terpinene (8.28%) and Allo-aromadendrene (7.44%). The essential oil had significant toxic effect against early fourth-instar larvae of C. quinquefasciatus with LC50=71.71 and LC90=143.41 ppm. The results could be useful in search of newer, safer and more effective natural larvicidal agent against C. quinquefasciatus. PMID:18566831

  11. Reappearance of Aedes aegypti (Diptera: Culicidae) in Lima, Peru.

    PubMed

    Andrade, C S; Cáceres, A G; Vaquerizo, A; Ibañez-Bernal, S; Cachay, L S

    2001-07-01

    We report here the reappearance of Aedes aegypti in the Rimac district, and summarize the history of this mosquito species in Peru since its first detection in 1852. On March 17 2000 were found Ae. aegypti and Culex quinquefasciatus in Mariscal Castilla town, Flor de Amancaes, San Juan de Amancaes, El Altillo and Santa Rosa in the Rimac district, Lima Province. PMID:11500764

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

    USGS Publications Warehouse

    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

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

    USGS Publications Warehouse

    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. Multiple insecticide resistances in the disease vector Culex p. quinquefasciatus from Western Indian Ocean.

    PubMed

    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

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

    PubMed Central

    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

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

    PubMed

    Lapointe, D A

    2008-07-01

    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.

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

    USGS Publications Warehouse

    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.

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

    PubMed

    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.

  19. Larvicidal activity of extracts from Ammi visnaga Linn. (Apiaceae) seeds against Culex quinquefasciatus Say. (Diptera: Culicidae).

    PubMed

    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.

  20. Ultrastructural analysis of midgut cells from Culex quinquefasciatus (Diptera: Culicidae) larvae resistant to Bacillus sphaericus.

    PubMed

    de Melo, Janaina Viana; Vasconcelos, Romero Henrique Teixeira; Furtado, André Freire; Peixoto, Christina Alves; Silva-Filha, Maria Helena Neves Lobo

    2008-12-01

    The larvicidal action of the entomopathogen Bacillus sphaericus towards Culex quinquefasciatus is due to the binary (Bin) toxin present in crystals, which are produced during bacterial sporulation. The Bin toxin needs to recognize and bind specifically to a single class of receptors, named Cqm1, which are 60-kDa alpha-glucosidases attached to the apical membrane of midgut cells by a glycosylphosphatidylinositol anchor. C. quinquefasciatus resistance to B. sphaericus has been often associated with the absence of the alpha-glucosidase Cqm1 in larvae midgut microvilli. In this work, we aimed to investigate, at the ultrastructural level, the midgut cells from C. quinquefasciatus larvae whose resistance relies on the lack of the Cqm1 receptor. The morphological analysis showed that midgut columnar cells from the resistant larvae are characterized by a pronounced production of lipid inclusions, throughout the 4th instar. At the end of this stage, resistant larvae had an increased size and number of these inclusions in the midgut cells, while only a small number were observed in the cells from susceptible larvae. The morphological differences in the midgut cells of resistant larvae found in this work suggested that the lack of the Cqm1 receptor, which also has a physiological role as being an alpha-glucosidase, can be related to changes in the cell metabolism. The ultrastructural effects of Bin toxin on midgut epithelial cells from susceptible and resistant larvae were also investigated. The cytopathological alterations observed in susceptible larvae treated with a lethal concentration of toxin included breakdown of the endoplasmic reticulum, mitochondrial swelling, microvillar disruption and vacuolization. Some effects were observed in cells from resistant larvae, although those alterations did not lead to larval death, indicating that the receptor Cqm1 is essential to mediate the larvicidal action of the toxin. This is the first ultrastructural study to show differences

  1. Nanoemulsion of eucalyptus oil and its larvicidal activity against Culex quinquefasciatus.

    PubMed

    Sugumar, S; Clarke, S K; Nirmala, M J; Tyagi, B K; Mukherjee, A; Chandrasekaran, N

    2014-06-01

    Filariasis is a mosquito-borne disease that causes lymphedema and the main vector is Culex quinquefasciatus. A simple measure was taken to eradicate the vector using nanoemulsion. Eucalyptus oil nanoemulsion was formulated in various ratios comprising of eucalyptus oil, tween 80 and water by ultrasonication. The stability of nanoemulsion was observed over a period of time and 1:2 ratios of eucalyptus oil (6%) and surfactant (12%) was found to be stable. The formulated eucalyptus oil nanoemulsion was characterized by transmission electron microscopy and dynamic light scattering. The nanoemulsion droplets were found to have a Z-average diameter of 9.4 nm and were spherical in shape. The larvicidal activity of eucalyptus oil nanoemulsion and bulk emulsion was tested and compared. Our nanoemulsion showed higher activity when compared to bulk emulsion. The histopathology of larvae-treated and untreated nanoemulsion was analyzed. Furthermore, biochemical assays were carried out to examine the effect of nanoemulsion on biochemical characteristics of larvae. The treated larval homogenate showed decrease in total protein content and a significant reduction in the levels of acetylcholinesterase. The levels of acid and alkaline phosphatase also showed reduction as compared to control larval homogenate.

  2. Association between Culex quinquefasciatus (Diptera: Culicidae) oviposition and structural features of belowground stormwater treatment devices.

    PubMed

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

    2010-01-01

    Belowground stormwater treatment devices referred to as Best Management Practices (BMPs) can be persistent sources of Culex quinquefasciatus Say (Diptera: Culicidae) mosquitoes and in urban environments necessitate routine monitoring and insecticide treatment for control. The design of certain structural features of BMPs may discourage mosquito entry and oviposition, potentially reducing the need for control measures. From August 2007 to November 2008, 29 BMPs were intermittently monitored for the presence of mosquitoes and compared against selected structural features. A bucket ovitrap was developed to estimate entry of oviposition-site-seeking females into BMPs via egg raft counts. The number of egg rafts collected was positively associated with larger diameters and shorter lengths of conveyance pipe from the nearest inlet or outlet and with increasing number of pickholes in BMP manhole covers. In contrast, the number of days pickholes were sealed against adult mosquito entry was negatively associated with eggs rafts. Findings suggest that the design of belowground BMPs and their conveyance systems can influence mosquito oviposition inside these structures. Specific design criteria with the greatest potential to minimize mosquito production and provide safe access for monitoring and control activities are discussed. PMID:20180310

  3. Nanoemulsion of eucalyptus oil and its larvicidal activity against Culex quinquefasciatus.

    PubMed

    Sugumar, S; Clarke, S K; Nirmala, M J; Tyagi, B K; Mukherjee, A; Chandrasekaran, N

    2014-06-01

    Filariasis is a mosquito-borne disease that causes lymphedema and the main vector is Culex quinquefasciatus. A simple measure was taken to eradicate the vector using nanoemulsion. Eucalyptus oil nanoemulsion was formulated in various ratios comprising of eucalyptus oil, tween 80 and water by ultrasonication. The stability of nanoemulsion was observed over a period of time and 1:2 ratios of eucalyptus oil (6%) and surfactant (12%) was found to be stable. The formulated eucalyptus oil nanoemulsion was characterized by transmission electron microscopy and dynamic light scattering. The nanoemulsion droplets were found to have a Z-average diameter of 9.4 nm and were spherical in shape. The larvicidal activity of eucalyptus oil nanoemulsion and bulk emulsion was tested and compared. Our nanoemulsion showed higher activity when compared to bulk emulsion. The histopathology of larvae-treated and untreated nanoemulsion was analyzed. Furthermore, biochemical assays were carried out to examine the effect of nanoemulsion on biochemical characteristics of larvae. The treated larval homogenate showed decrease in total protein content and a significant reduction in the levels of acetylcholinesterase. The levels of acid and alkaline phosphatase also showed reduction as compared to control larval homogenate. PMID:24401169

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

    PubMed

    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 < 0.05) among the 5 rows, with mortality continuously decreasing with increasing distance from sprayer. Both sprayers provided on average >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. PMID:25843094

  5. Stability of Culex quinquefasciatus resistance to Bacillus sphaericus evaluated by molecular tools.

    PubMed

    Amorim, Liliane Barbosa; de Barros, Rosineide Arruda; Chalegre, Karlos Diogo de Melo; de Oliveira, Cláudia Maria Fontes; Regis, Lêda Narcisa; Silva-Filha, Maria Helena Neves Lobo

    2010-04-01

    Bacillus sphaericus binary toxin action on Culex quinquefasciatus larvae relies on the binding to Cqm1alpha-glucosidases, which act as midgut receptors. Resistance of two laboratory-selected colonies is associated with the allele cqm1(REC) that prevents Cqm1 expression as membrane-bound molecules. This study evaluated stability of resistance after the interruption of selection pressure and introduction of susceptible individuals in these colonies. Bioassays showed that frequency of resistant larvae did not decrease throughout 11 generations, under these conditions, and it was associated to a similar frequency of larvae lacking the Cqm1alpha-glucosidase receptor, detected by in gel enzymatic assays. Direct screening of the cqm1(REC) allele, by specific PCR, showed that its frequency remained stable throughout 11 generations. Parental resistant colony did not display biological costs regarding fecundity, fertility and pupal weight and data from susceptibility assays, enzymatic assays and PCR screening showed that cqm1(REC) was not disfavored in competition with the susceptible allele and persisted in the progenies, in the lack of selection pressure. Characterization of molecular basis of resistance is essential for developing diagnostic tools and data have relevant implication for the establishment of strategies for resistance management. PMID:20211258

  6. Laboratory selection of resistance to spinosad in Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Su, Tianyun; Cheng, Min-Lee

    2014-03-01

    A southern house mosquito Culex quinquefasciatus Say colony was established from surviving late instars and pupae from a semifield evaluation on Natular XRG (a granular formulation containing 2.5% spinosad). The initial lethal levels ofNatular XRG against this colony were determined in the laboratory for the first-generation progeny (designated as F1). Selection pressure was applied at LC70-90 levels to 10,000-15,000 late third- and early fourth-instar larvae of each generation with Natular XRG. Susceptibility changes in response to selection were determined every other generation, where a gradual and steady decline in susceptibility occurred from generation F1 to F35, followed by significant decline from generations F37 to F45 For reference purposes, susceptibility of freshly collected wild populations as well as a laboratory colony of the same species was also determined concurrently, which fluctuated within a slightly wider range for the wild populations and a tighter range for the laboratory colony. By comparing with wild populations and laboratory reference colony, tolerance to spinosad was observed from generations up to F9 in the selected population. Resistance levels increased gradually from generation F11 to F35, and elevated significantly from generations F37 to F45, when resistance ratios reached 1,415.3- to 2,229.9-fold at LC50 and 9,613.1- to 17,062.6-fold at LC90. Possible mechanisms of resistance development to spinosad were discussed.

  7. [Role of Culex quinquefasciatus in the transmission of bancroftian filariasis in the Federal Islamic Republic of Comoros (Indian Ocean)].

    PubMed

    Sabatinelli, G; Ranieri, E; Gianzi, F P; Papakay, M; Cancrini, G

    1994-03-01

    In October 1988-January 1989, as a part of a malaria and filariasis control programme in Federal Islamic Republic of Comoros an entomological survey was carried out in 19 rural and urban localities of Grande Comore. Anjouan and Moheli Islands. The potential breeding places were examined and pyrethrum spray catches were made to evaluate the indoor resting densities of mosquitos. A total of 14.578 adult mosquitos potential vectors of filariasis was collected: 94.5% Culex quinquefasciatus, 3.5% Anopheles gambiae s. str. 1.9% A. funestus and 0.1% other anopheline species. A. funestus, uniformly spread in Moheli, was present only in the south-west coast of Anjouan and absent in Grande Comore. A. gambiae and Cx quinquefasciatus were present in Grande Comore. A. gambiae and Cx quinquefasciatus were present in the three islands with different densities in the villages. Only Cx quinquefasciatus specimens la maximum of 150 for each locality) were dissected to search filaria larvae being the Anopheles specimens used to evaluate the malaria transmission. The global infection rate (9.4%) and the infectivity rate (0.9%) observed in Cx quinquefasciatus are higher than indices reported in previous surveys. All the larvae in the third development instar (L3) were identified as Wuchereria bancrofti. The results suggest that in FIR of Comoros W. bancrofti is well adopted to local Cx quinquefasciatus population. Because of the presence of high mosquito density this species plays a prominent role in the transmission of lymphatic filariasis in that area. The high transmission levels calls for the implementation of a specific control program.

  8. Synthesis of eco-friendly silver nanoparticles from Morinda tinctoria leaf extract and its larvicidal activity against Culex quinquefasciatus.

    PubMed

    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.

  9. Mosquito larvicidal and biting deterrency activity of bud of Polianthes tuberosa plants extract against Anopheles stephensi and Culex quinquefasciatus.

    PubMed

    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 < 0.05) mortality was recorded at a concentration of 60 ppm. The chloroform: methanol (1:1, v/v) solvent extract provide 4h protection against Cx. quinquefasciatus and 5h against An. stephensi from biting. Both crude and chloroform: methanol (1:1, v/v) extract showed good result against Cx. quinquefasciatus, so it could be used as a mosquito larvicide agent. There is no changes in the activity non-target organism so, it is safe to use.

  10. Predatory efficiency of the water bug Sphaerodema annulatum on mosquito larvae (Culex quinquefasciatus) and its effect on the adult emergence.

    PubMed

    Aditya, G; Bhattacharyya, S; Kundu, N; Saha, G K; Raut, S K

    2004-11-01

    The daily number of IV instar larva of Culex quinquefasciatus killed, rate of pupation and adult emergence was noted in presence of the predatory water bug Sphaerodema annulatum for a period of seven consecutive days, experimentally, in the laboratory. The rate of IV instar larva killed by the water bugs on an average was 65.17 per day. The rate of pupation ranged between 7.6 and 48 in control while in presence of water bugs it ranged between 6 and 35. The rate of adult emergence in control experiments varied between 1.4 and 4.8 per day, which was reduced to only 0.4-28.8 per day in case of the water bugs. The results clearly indicate that the water bugs on its way of predation reduces the rate of pupation and adult emergence of Cx. quinquefasciatus significantly which calls for an extensive field trials.

  11. Vertical transmission of St. Louis encephalitis virus in Culex quinquefasciatus (Diptera: Culicidae) in Córdoba, Argentina.

    PubMed

    Flores, Fernando Sebastián; Diaz, Luis Adrián; Batallán, Gonzalo Pedro; Almirón, Walter Ricardo; Contigiani, Marta Silvia

    2010-12-01

    Arbovirus vector transmission is interrupted when vector abundance decreases or disappears in temperate regions during the winter season. Although the primary overwintering mechanism for many arboviruses in nature remains unknown, vertical transmission is one potential mechanism. Vertical transmission functions as an overwintering mechanism for St. Louis encephalitis virus (SLEV) in temperate areas of Argentina, where SLEV is endemic. The aim of this project was to detect vertical transmission of SLEV in Culex quinquefasciatus mosquitoes. Under laboratory conditions, SLEV vertical transmission (3.4 minimum infection rates) was detected in larvae (1:256) and adults F₁ (1:406). There were no positive larvae for SLEV among over 2011 analyzed individuals collected in nature. This is the first study to confirm experimental vertical transmission of SLEV in Cx. quinquefasciatus populations from Argentina, though additional overwintering mechanisms (e.g., nontraditional vectors such as ticks and nondiapausing female mosquitoes) should be considered. PMID:20426683

  12. Temporal variations in biting density and rhythm of Culex quinquefasciatus in tea agro-ecosystem of Assam, India.

    PubMed

    Mahanta, B; Handique, R; Dutta, P; Narain, K; Mahanta, J

    1999-12-01

    Temporal changes in the biting density and host-seeking periodicity of Culex quinquefasciatus, the vector of bancroftian filariasis, were studied for two years in the tea agro-ecosystem of Assam, India. Average biting density of the vector varied from 0.8/hour in December to 13.3/hour in March. Minimum temperature was found to have a limiting effect on the biting density of the vector mosquitos. Multiple regression analysis showed that the rainfall and minimum temperature were significant factors influencing biting density of this vector mosquito. The biting rhythm of Cx. quinquefasciatus was found to be nocturnal with two distinct peak periods of biting activity. The first peak was around 19.00 to 20.00 hours and the second peak period was around 22.00 to 23.00 hours. Biting activity however was seen throughout the night with declining trend as the night proceeded. PMID:10928380

  13. Mosquito larvicidal activity of aromatic medicinal plant oils against Aedes aegypti and Culex pipiens pallens.

    PubMed

    Lee, Hoi-Seon

    2006-06-01

    Larvicidal activity of essential oils derived from 11 aromatic medicinal plants against early 4th-stage larvae of Aedes aegypti and Culex pipiens pallens was tested in the laboratory. At 100 ppm, the essential oils of all plants caused 100% mortality against Ae. aegypti and Cx. pipiens pallens. At 25 ppm, the essential oils of Citrus bergamia, Cuminum myrrha, and Pimenta racemosa caused 100% mortality against larvae of Ae. aegypti and Cx. pipiens pallens. The oil of C. begamia caused 32.5% and 24.5% mortality against Ae. aegypti and Cx. pipiens pallens at 12.5 ppm, but 24.2% and 0% mortality against Ae. aegypti and Cx. pipiens pallens at 6.25 ppm, respectively. The oil of P. racemosa caused 52.3% and 38.5% mortality against Ae. aegypti and Cx. pipiens pallens at 12.5 ppm, but 32.2% and 0% mortality against Ae. aegypti and Cx. pipiens pallens at 6.25 ppm, respectively. The larvicidal activity of oils of C. bergamia, C. myrrha, and P. racemosa was significantly reduced when used at 6.25 ppm. These plants warrant further studies as possible agents for mosquito control.

  14. Distribution of organophosphate and carbamate resistance in Culex pipiens quinquefasciatus (Diptera: Culicidae) in West Africa.

    PubMed

    Chandre, F; Darriet, F; Doannio, J M; Rivière, F; Pasteur, N; Guillet, P

    1997-11-01

    The distribution of organophosphate and carbamate resistance was investigated in 33 samples of Culex pipiens quinquefasciatus Say from 25 cities in Côte d'Ivoire and Burkina Faso. Organophosphate resistance levels were higher in Côte d'Ivoire than in Burkina Faso. Chlorpyrifos resistance ratios at LC95 ranged from 4 to 30 times in Côte d'Ivoire and from 3 to 6 times in Burkina Faso. For temephos, ratios ranged from 3 to 18 and from 1 to 2, respectively. Of 27 samples from Côte d'Ivoire, 25 also displayed cross resistance to carbamates as shown by a mortality plateau in bioassays with propoxur and carbosulfan (similar to chlorpyrifos). Cross resistance to organophosphates and carbamates was caused by an insensitive acetylcholinesterase allele (AceR). This gene was absent from Burkina Faso, except in Niangoloko near the Côte d'Ivoire border. Organophosphate resistance also was associated with the presence of A2-B2 overproduced esterases which had higher frequencies in Côte d'Ivoire (75-100%) than in Burkina Faso (40-50%). Two other esterases with the same electrophoretic mobility as C2 from Puerto Rico and B1 from California were identified for the 1st time in West Africa. "C2" was widespread, whereas "B1" was present in only a few mosquitoes from Côte d'Ivoire. These differences in resistance patterns should be taken into consideration in planning urban mosquito control strategies within 2 countries.

  15. Aqueous Neem Extract Versus Neem Powder on Culex quinquefasciatus: Implications for Control in Anthropogenic Habitats

    PubMed Central

    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 (χ2 = 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. PMID:22233153

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

    PubMed

    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.

  17. Co-selection and replacement of resistance alleles to Lysinibacillus sphaericus in a Culex quinquefasciatus colony.

    PubMed

    Chalegre, Karlos Diogo de Melo; Tavares, Daniella A; Romão, Tatiany P; de Menezes, Heverly Suzany G; Nascimento, Nathaly A; de Oliveira, Cláudia Maria F; de-Melo-Neto, Osvaldo P; Silva-Filha, Maria Helena N L

    2015-09-01

    The Cqm1 α-glucosidase, expressed within the midgut of Culex quinquefasciatus mosquito larvae, is the receptor for the Binary toxin (Bin) from the entomopathogen Lysinibacillus sphaericus. Mutations of the Cqm1 α-glucosidase gene cause high resistance levels to this bacterium in both field and laboratory populations, and a previously described allele, cqm1REC, was found to be associated with a laboratory-resistant colony (R2362). This study described the identification of a novel resistance allele, cqm1REC-2, that was co-selected with cqm1REC within the R2362 colony. The two alleles display distinct mutations but both generate premature stop codons that prevent the expression of midgut-bound Cqm1 proteins. Using a PCR-based assay to monitor the frequency of each allele during long-term maintenance of the resistant colony, cqm1REC was found to predominate early on but later was replaced by cqm1REC-2 as the most abundant resistance allele. Homozygous larvae for each allele were then generated that displayed similar high-resistance phenotypes with equivalent low levels of transcript and lack of protein expression for both cqm1REC and cqm1REC-2. In progeny from a cross of homozygous individuals for each allele at a 1 : 1 ratio, analyzed for ten subsequent generations, cqm1REC showed a higher frequency than cqm1REC-2. The replacement of cqm1REC by cqm1REC -2 observed in the R2362 colony, kept for 210 generations, indicates changes in fitness related to traits that are unknown but linked to these two alleles, and constitutes a unique example of evolution of resistance within a controlled laboratory environment. PMID:26131741

  18. Comparative efficacies of permethrin-, deltamethrin- and alpha-cypermethrin-treated nets, against Anopheles arabiensis and Culex quinquefasciatus in northern Tanzania.

    PubMed

    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.

  19. Monitoring temporal fluctuations of Culex quinquefasciatus using oviposition traps containing attractant and larvicide in an urban environment in Recife, Brazil.

    PubMed

    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.

  20. Toxicity of Boswellia dalzielii (Burseraceae) Leaf Fractions Against Immature Stages of Anopheles gambiae (Giles) and Culex quinquefasciatus (Say) (Diptera: Culicidae)

    PubMed Central

    Younoussa, Lame; Nukenine, Elias Nchiwan; Esimone, Charles Okechukwu

    2016-01-01

    Mosquitoes are vectors of several human pathogens, and great attention has recently been placed on insecticides from plant-derived products, in search for mosquito control agents. This study, thus, investigated the potency of Boswellia dalzielii methanol leaf extract and its four fractions as mosquito ovicide, larvicide, and pupicide against Anopheles gambiae and Culex quinquefasciatus. The plant products were tested at the following concentrations: 125, 250, 500, 1000, and 2000 ppm on eggs and 312.5, 625, 1250, and 2500 ppm on the larvae and pupae of the mosquitoes. For results, hatchability of A. gambiae eggs was reduced to 5% with n-hexane fraction at 2000 ppm. Among the plant products tested, n-hexane fraction was most toxic against A. gambiae (LC50 = 385.9 ppm) and C. quinquefasciatus (LC50 = 3394.9 ppm). The n-hexane fraction of B. dalzielii might be used as a mosquitocidal agent in the breeding sites of A. gambiae and C. quinquefasciatus. PMID:27279752

  1. Toxicity of Boswellia dalzielii (Burseraceae) Leaf Fractions Against Immature Stages of Anopheles gambiae (Giles) and Culex quinquefasciatus (Say) (Diptera: Culicidae).

    PubMed

    Younoussa, Lame; Nukenine, Elias Nchiwan; Esimone, Charles Okechukwu

    2016-01-01

    Mosquitoes are vectors of several human pathogens, and great attention has recently been placed on insecticides from plant-derived products, in search for mosquito control agents. This study, thus, investigated the potency of Boswellia dalzielii methanol leaf extract and its four fractions as mosquito ovicide, larvicide, and pupicide against Anopheles gambiae and Culex quinquefasciatus. The plant products were tested at the following concentrations: 125, 250, 500, 1000, and 2000 ppm on eggs and 312.5, 625, 1250, and 2500 ppm on the larvae and pupae of the mosquitoes. For results, hatchability of A. gambiae eggs was reduced to 5% with n-hexane fraction at 2000 ppm. Among the plant products tested, n-hexane fraction was most toxic against A. gambiae (LC50 = 385.9 ppm) and C. quinquefasciatus (LC50 = 3394.9 ppm). The n-hexane fraction of B. dalzielii might be used as a mosquitocidal agent in the breeding sites of A. gambiae and C. quinquefasciatus. PMID:27279752

  2. Colour Cues: Effects of Ipomoea Plant Extract on Culex quinquefasciatus Say Gravid Females in Choosing Oviposition Site

    PubMed Central

    Zuharah, Wan Fatma; Thiagaletchumi, Maniam; Fadzly, Nik

    2016-01-01

    The interaction between plants and insects is dynamic, and may favour either the plant or the insect. Plant chemicals are deeply implicated in this relationship and influence insect behaviour. Here, we investigated the oviposition behaviour response of Culex quinquefasciatus mosquitoes based on the colour cues produced by Ipomoea cairica leaves extract. In this study, two sets of oviposition choice experiments were conducted: (1) single solution in a cage; and (2) multiple concentration solutions in a cage. In the single solution experiment, only 1 available oviposition site was offered to 5 gravid females and in the multiple concentration tests, 4 available oviposition sites were offered to 20 gravid females. The tested concentrations were set up at 100 mL of: (1) control (distilled water only); (2) 50 ppm; (3) 150 ppm; and (4) 300 ppm of I. cairica plant extracts. The highest concentration of 300 ppm appeared to show the highest intensity with the darkest colour followed by 150 ppm and 50 ppm concentrations. More gravid females were found drowned in the highest concentration, 300 ppm of acethonilic leaves extract, compared to 150 ppm and 50 ppm of the tested extract. No eggs were found in all tested solutions. The studied extract was found to effectively attract gravid Cx. quinquefasciatus females and subsequently cause mortality and inhibit egg deposition. The interference caused by the acethonilic extract of I. cairica on the oviposition activity of Cx. quinquefasciatus can result in better control of the vector insect. PMID:27688853

  3. Detection of Oropouche virus segment S in patients and inCulex quinquefasciatus in the state of Mato Grosso, Brazil

    PubMed Central

    Cardoso, Belgath Fernandes; Serra, Otacília Pereira; Heinen, Letícia Borges da Silva; Zuchi, Nayara; de Souza, Victor Costa; Naveca, Felipe Gomes; dos Santos, Marcelo Adriano Mendes; Slhessarenko, Renata Dezengrini

    2015-01-01

    This study aimed to investigate the circulation of Orthobunyavirus species in the state of Mato Grosso (MT) Brazil. During a dengue outbreak in 2011/2012, 529 serum samples were collected from patients with acute febrile illness with symptoms for up to five days and 387 pools of female Culex quinquefasciatus captured in 2013 were subjected to nested-reverse transcription-polymerase chain reaction for segment S of the Simbu serogroup followed by nucleotide sequencing and virus isolation in Vero cells. Patients (5/529; 0.9%) from Cuiabá (n = 3), Várzea Grande (n = 1) and Nova Mutum (n = 1) municipalities were positive for the S segment of Oropouche virus (OROV). Additionally, eight/387 Cx. quinquefasciatus pools were positive for the segment, with a minimum infection rate of 2.3. Phylogenetic analysis indicated that all the samples belong to the subgenotype Ia, presenting high homology with OROV strains obtained from humans and animals in the Brazilian Amazon. The present paper reports the first detection of an Orthobunyavirus, possibly OROV, in patients and in Cx. quinquefasciatus mosquitoes in MT. This finding reinforces the notion that arboviruses frequently reported in the Amazon Region circulate sporadically in MT during dengue outbreaks. PMID:26517653

  4. Ability of newly emerged adult Culex quinquefasciatus (Diptera: Culicidae) mosquitoes to exit belowground stormwater treatment systems via lateral conveyance pipes.

    PubMed

    Metzger, Marco E; Harbison, Justin E; Burns, Joseph E; Hu, Renjie

    2012-03-01

    Culex quinquefasciatus Say mosquitoes flourish in belowground stormwater systems in the southern United States. Recent evidence suggests that oviposition-site-seeking females may have difficulties locating, entering, and ovipositing inside permanent water chambers when surface entry through pickholes in manhole covers are sealed. It remains unknown, however, if newly emerged adults are able to detect cues necessary to exit these partly sealed systems via lateral conveyance pipes or if they perish belowground. Fourth instar Cx. quinquefasciatus were placed within proprietary belowground stormwater treatment systems to determine the percentage of newly emerged adults able to escape treatment chambers via a single lateral conveyance pipe. Overall, 56% of deployed mosquitoes were captured in adult exit traps with an 1:1 male:female ratio. The percentage of adults captured varied significantly among chambers, but was not associated with structural site characteristics such as the chamber depth or the length and course of conveyance pipe to the exit trap. Empirical observations suggested that longbodied cellar spiders, Pholcus phalangioides (Fuesslin), ubiquitous in these structures, may have reduced adult trap capture. Findings demonstrate that newly emerged Cx. quinquefasciatus can exit subterranean chambers under potentially difficult structural conditions but suggest that a portion may perish in the absence of surface exit points in manhole shafts.

  5. Colour Cues: Effects of Ipomoea Plant Extract on Culex quinquefasciatus Say Gravid Females in Choosing Oviposition Site.

    PubMed

    Zuharah, Wan Fatma; Thiagaletchumi, Maniam; Fadzly, Nik

    2016-08-01

    The interaction between plants and insects is dynamic, and may favour either the plant or the insect. Plant chemicals are deeply implicated in this relationship and influence insect behaviour. Here, we investigated the oviposition behaviour response of Culex quinquefasciatus mosquitoes based on the colour cues produced by Ipomoea cairica leaves extract. In this study, two sets of oviposition choice experiments were conducted: (1) single solution in a cage; and (2) multiple concentration solutions in a cage. In the single solution experiment, only 1 available oviposition site was offered to 5 gravid females and in the multiple concentration tests, 4 available oviposition sites were offered to 20 gravid females. The tested concentrations were set up at 100 mL of: (1) control (distilled water only); (2) 50 ppm; (3) 150 ppm; and (4) 300 ppm of I. cairica plant extracts. The highest concentration of 300 ppm appeared to show the highest intensity with the darkest colour followed by 150 ppm and 50 ppm concentrations. More gravid females were found drowned in the highest concentration, 300 ppm of acethonilic leaves extract, compared to 150 ppm and 50 ppm of the tested extract. No eggs were found in all tested solutions. The studied extract was found to effectively attract gravid Cx. quinquefasciatus females and subsequently cause mortality and inhibit egg deposition. The interference caused by the acethonilic extract of I. cairica on the oviposition activity of Cx. quinquefasciatus can result in better control of the vector insect. PMID:27688853

  6. Colour Cues: Effects of Ipomoea Plant Extract on Culex quinquefasciatus Say Gravid Females in Choosing Oviposition Site

    PubMed Central

    Zuharah, Wan Fatma; Thiagaletchumi, Maniam; Fadzly, Nik

    2016-01-01

    The interaction between plants and insects is dynamic, and may favour either the plant or the insect. Plant chemicals are deeply implicated in this relationship and influence insect behaviour. Here, we investigated the oviposition behaviour response of Culex quinquefasciatus mosquitoes based on the colour cues produced by Ipomoea cairica leaves extract. In this study, two sets of oviposition choice experiments were conducted: (1) single solution in a cage; and (2) multiple concentration solutions in a cage. In the single solution experiment, only 1 available oviposition site was offered to 5 gravid females and in the multiple concentration tests, 4 available oviposition sites were offered to 20 gravid females. The tested concentrations were set up at 100 mL of: (1) control (distilled water only); (2) 50 ppm; (3) 150 ppm; and (4) 300 ppm of I. cairica plant extracts. The highest concentration of 300 ppm appeared to show the highest intensity with the darkest colour followed by 150 ppm and 50 ppm concentrations. More gravid females were found drowned in the highest concentration, 300 ppm of acethonilic leaves extract, compared to 150 ppm and 50 ppm of the tested extract. No eggs were found in all tested solutions. The studied extract was found to effectively attract gravid Cx. quinquefasciatus females and subsequently cause mortality and inhibit egg deposition. The interference caused by the acethonilic extract of I. cairica on the oviposition activity of Cx. quinquefasciatus can result in better control of the vector insect.

  7. Detection of Oropouche virus segment S in patients and inCulex quinquefasciatus in the state of Mato Grosso, Brazil.

    PubMed

    Cardoso, Belgath Fernandes; Serra, Otacília Pereira; Heinen, Letícia Borges da Silva; Zuchi, Nayara; Souza, Victor Costa de; Naveca, Felipe Gomes; Santos, Marcelo Adriano Mendes dos; Slhessarenko, Renata Dezengrini

    2015-09-01

    This study aimed to investigate the circulation of Orthobunyavirus species in the state of Mato Grosso (MT) Brazil. During a dengue outbreak in 2011/2012, 529 serum samples were collected from patients with acute febrile illness with symptoms for up to five days and 387 pools of female Culex quinquefasciatus captured in 2013 were subjected to nested-reverse transcription-polymerase chain reaction for segment S of the Simbu serogroup followed by nucleotide sequencing and virus isolation in Vero cells. Patients (5/529; 0.9%) from Cuiabá (n = 3), Várzea Grande (n = 1) and Nova Mutum (n = 1) municipalities were positive for the S segment of Oropouche virus (OROV). Additionally, eight/387 Cx. quinquefasciatus pools were positive for the segment, with a minimum infection rate of 2.3. Phylogenetic analysis indicated that all the samples belong to the subgenotype Ia, presenting high homology with OROV strains obtained from humans and animals in the Brazilian Amazon. The present paper reports the first detection of an Orthobunyavirus, possibly OROV, in patients and in Cx. quinquefasciatus mosquitoes in MT. This finding reinforces the notion that arboviruses frequently reported in the Amazon Region circulate sporadically in MT during dengue outbreaks.

  8. 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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  9. Efficacy of larvividal and pupicidal properties of Acalypha alnifolia Klen ex Willd. (Euphorbiaceae) leaf extract and Metarhisium anisopilae (Metsch.) against Culex quinquefasciatus Say. (Diptera: Cuclicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was made to determine the lethal effects of Acalypha alnifolia leaf extract and the microbial insecticide Metarizhium anisopliae against larvae and pupae of the filariasis vector Culex quinquefasciatus. Methanol extracts of A. alnifolia were most effective in this regard with LC50 values...

  10. 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..

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  11. Single nucleotide deletion of cqm1 gene results in the development of resistance to Bacillus sphaericus in Culex quinquefasciatus.

    PubMed

    Guo, Qing-yun; Cai, Quan-xin; Yan, Jian-ping; Hu, Xiao-min; Zheng, Da-sheng; Yuan, Zhi-ming

    2013-09-01

    The entomopathogen Bacillus sphaericus is one of the most effective biolarvicides used to control the Culex species of mosquito. The appearance of resistance in mosquitoes to this bacterium, however, remains a threat to its continuous use in integrated mosquito control programs. Previous work showed that the resistance to B. sphaericus in Culex colonies was associated with the absence of the 60-kDa binary toxin receptor (Cpm1/Cqm1), an alpha-glucosidase present in the larval midgut microvilli. In this work, we studied the molecular basis of the resistance developed by Culex quinquefasciatus to B. sphaericus C3-41. The cqm1 genes were cloned from susceptible (CqSL) and resistant (CqRL/C3-41) colonies, respectively. The sequence of the cDNA and genomic DNA derived from CqRL/C3-41 colony differed from that of CqSL one by a one-nucleotide deletion which resulted in a premature stop codon, leading to production of a truncated protein. Recombinant Cqm1S from the CqSL colony expressed in Escherichia coli specifically bound to the Bin toxin and had α-glucosidase activity, whereas the Cqm1R from the CqRL/C3-41 colony, with a deletion of three quarters of the receptor's C-terminal lost its α-glucosidase activity and could not bind to the binary toxin. Immunoblotting experiments showed that Cqm1 was undetectable in CqRL/C3-41 larvae, although the gene was correctly transcribed. Thus, the cqm1R represents a new allele in C. quinquefasciatus that confers resistance to B. sphaericus. PMID:23871751

  12. Efficacy of leaves extract of Calotropis procera Ait. (Asclepiadaceae) in controlling Anopheles arabiensis and Culex quinquefasciatus mosquitoes.

    PubMed

    Elimam, Abdalla M; Elmalik, Khitma H; Ali, Faysal S

    2009-10-01

    The present study aimed to investigate, the larvicidal, adult emergence inhibition and oviposition deterrent activity of aqueous leaves extract of Calotropis procera against Anopheles arabiensis and Culex quinquefasciatus as natural mosquito larvicide. The larvicidal activity was monitored against 2nd, 3rd and 4th instar larvae of each mosquito species 24 h post-treatment. Adult emergence inhibition activity was tested by exposing 3rd instar larvae of each mosquito species to different concentrations of extracts (200, 400, 600, 800 and 1000 ppm for An. arabiensis and 100, 200, 300, 400, 500 and 600 ppm for Cx. quinquefasciatus). Probit analysis was used to analyze data from bioassay experiments. The oviposition deterrent activity was tested by using three different concentrations of extracts (1000, 500 and 200 for An. arabiensis, and 1000, 500 and 100 for Cx. quinquefasciatus) that caused high, moderate and low larval mortality in the larvicidal experiment against 3rd instar larvae. It was found that, LC50-LC90 values calculated were 273.53-783.43, 366.44-1018.59 and 454.99-1224.62 ppm for 2nd, 3rd and 4th larval instars, respectively, of An. arabiensis and 187.93-433.51, 218.27-538.27 and 264.85-769.13 ppm for 2nd, 3rd and 4th larval instars, respectively, of Cx. quinquefasciatus. Fifty percent of adult emergence inhibition (EI50) was shown at 277.90 and 183.65 ppm for An. arabiensis and Cx. quinquefasciatus, respectively. The pupal stage was not affected till a concentration of 5000 ppm. The extract showed oviposition deterrence and effective repellence against both mosquito species at different concentrations, with the observation on that maximal eggs were laid in low concentration of extract. These results suggest that the leaves extract of C. procera possess remarkable larvicidal, adult emergence inhibitor, repellent and oviposition deterrent effect against both An. arabiensis and Cx. quinquefasciatus, and might be used as natural biocides for mosquito

  13. Larvicidal potential of carvacrol and terpinen-4-ol from the essential oil of Origanum vulgare (Lamiaceae) against Anopheles stephensi, Anopheles subpictus, Culex quinquefasciatus and Culex tritaeniorhynchus (Diptera: Culicidae).

    PubMed

    Govindarajan, Marimuthu; Rajeswary, Mohan; Hoti, S L; Benelli, Giovanni

    2016-02-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. However, the use of synthetic insecticides to control Culicidae may lead to resistance, high operational costs and adverse non-target effects. Nowadays, plant-borne mosquitocides may serve as suitable alternative in the fight against mosquito vectors. In this study, the mosquito larvicidal activity of Origanum vulgare (Lamiaceae) leaf essential oil (EO) and its major chemical constituents was evaluated against the malaria vectors Anopheles stephensi and An. subpictus, the filariasis vector Culex quinquefasciatus and the Japanese encephalitis vector Cx. tritaeniorhynchus. The chemical composition of the EO was analyzed by gas chromatography-mass spectroscopy. GC-MS revealed that the essential oil of O. vulgare contained 17 compounds. The major chemical components were carvacrol (38.30%) and terpinen-4-ol (28.70%). EO had a significant toxic effect against early third-stage larvae of An. stephensi, An. subpictus, Cx. quinquefasciatus and Cx. tritaeniorhynchus, with LC50 values of 67.00, 74.14, 80.35 and 84.93 μg/ml. The two major constituents extracted from the O. vulgare EO were tested individually for acute toxicity against larvae of the four mosquito vectors. Carvacrol and terpinen-4-ol appeared to be most effective against An. stephensi (LC50=21.15 and 43.27 μg/ml, respectively) followed by An. subpictus (LC50=24.06 and 47.73 μg/ml), Cx. quinquefasciatus (LC50=26.08 and 52.19 μg/ml) and Cx. tritaeniorhynchus (LC50=27.95 and 54.87 μg/ml). Overall, this research adds knowledge to develop newer and safer natural larvicides against malaria, filariasis and Japanese encephalitis mosquito vectors. PMID:26850541

  14. Mtx toxins from Lysinibacillus sphaericus enhance mosquitocidal cry-toxin activity and suppress cry-resistance in Culex quinquefasciatus

    PubMed Central

    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. PMID:24144574

  15. Mtx toxins from Lysinibacillus sphaericus enhance mosquitocidal cry-toxin activity and suppress cry-resistance in Culex quinquefasciatus.

    PubMed

    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.

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

    PubMed

    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.

  17. Gene structure and expression of nanos (nos) and oskar (osk) orthologues of the vector mosquito, Culex quinquefasciatus.

    PubMed

    Juhn, J; Marinotti, O; Calvo, E; James, A A

    2008-09-01

    The products of the maternal-effect genes, nanos (nos) and oskar (osk), are important for the development of germ cells in insects. Furthermore, these genes have been proposed as candidates for donating functional DNA regulatory sequences for use in gene drive systems to control transmission of mosquito-borne pathogens. The nos and osk genes of the cosmopolitan vector mosquito, Culex quinquefasciatus, encode proteins with domains common to orthologues found in other mosquitoes. Expression analyses support the conclusion that the role of these genes is conserved generally among members of the nematocera. Hybridization in situ analyses reveal differences in mRNA distribution in early embryos in comparison with the cyclorraphan, Drosophila melanogaster, highlighting a possible feature in the divergence of the clades each insect represents.

  18. Emergence of resistance and resistance management in field populations of tropical Culex quinquefasciatus to the microbial control agent Bacillus sphaericus.

    PubMed

    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. A second independent resistance mechanism to Bacillus sphaericus binary toxin targets its alpha-glucosidase receptor in Culex quinquefasciatus.

    PubMed

    Romão, Tatiany Patrícia; de Melo Chalegre, Karlos Diogo; Key, Shana; Ayres, Constância Flávia Junqueira; Fontes de Oliveira, Cláudia Maria; de-Melo-Neto, Osvaldo Pompílio; Silva-Filha, Maria Helena Neves Lobo

    2006-04-01

    The entomopathogen Bacillus sphaericus is an important tool for the vector control of Culex sp., and its effectiveness has been validated in field trials. The appearance of resistance to this bacterium, however, remains a threat to its use, and attempts have been made to understand the resistance mechanisms. Previous work showed that the resistance to B. sphaericus in a Culex quinquefasciatus colony is associated with the absence of the approximately 60-kDa binary toxin receptor in larvae midgut microvilli. Here, the gene encoding the C. quinquefasciatus toxin receptor, Cqm1, was cloned and sequenced from a susceptible colony. The deduced amino-acid sequence confirmed its identity as an alpha-glucosidase, and analysis of the corresponding gene sequence from resistant larvae implicated a 19-nucleotide deletion as the basis for resistance. This deletion changes the ORF and originates a premature stop codon, which prevents the synthesis of the full-length Cqm1. Expression of the truncated protein, however, was not detected when whole larvae extracts were probed with antibodies raised against an N-terminal 45-kDa recombinant fragment of Cqm1. It seems that the premature stop codon directs the mutated cqm1 to the nonsense-mediated decay pathway of mRNA degradation. In-gel assays confirmed that a single alpha-glucosidase protein is missing from the resistant colony. Further in vitro affinity assays showed that the recombinant fragment binds to the toxin, and mapped the binding site to the N-terminus of the receptor. PMID:16689941

  20. Mtx Toxins Synergize Bacillus sphaericus and Cry11Aa against Susceptible and Insecticide-Resistant Culex quinquefasciatus Larvae▿

    PubMed Central

    Wirth, Margaret C.; Yang, Yangkun; Walton, William E.; Federici, Brian A.; Berry, Colin

    2007-01-01

    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 (LC50) of Mtx-1 and Mtx-2 of 0.246 and 4.13 μg/ml, respectively. The LC50s were 0.406 to 0.430 μg/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. PMID:17704274

  1. Bioefficacy of plant-mediated gold nanoparticles and Anthocepholus cadamba on filarial vector, Culex quinquefasciatus (Insecta: Diptera: Culicidae).

    PubMed

    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.

  2. Relative toxicity of neem fruit, bitter gourd, and castor seed extracts against the larvae of filaria vector, Culex quinquefasciatus (Say).

    PubMed

    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.

  3. Relative toxicity of neem fruit, bitter gourd, and castor seed extracts against the larvae of filaria vector, Culex quinquefasciatus (Say).

    PubMed

    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. PMID:19562373

  4. Intermolecular interaction between Cry2Aa and Cyt1Aa and its effect on larvicidal activity against Culex quinquefasciatus.

    PubMed

    Bideshi, Dennis K; Waldrop, Greer; Fernandez-Luna, Maria Teresa; Diaz-Mendoza, Mercedes; Wirth, Margaret C; Johnson, Jeffrey J; Park, Hyun-Woo; Federici, Brian A

    2013-08-01

    The Cyt1Aa protein of Bacillus thuringiensis susbp. israelensis elaborates demonstrable toxicity to mosquito larvae, but more importantly, it enhances the larvicidal activity of this species Cry proteins (Cry11Aa, Cry4Aa, and Cry4Ba) and delays the phenotypic expression of resistance to these that has evolved in Culex quinquefasciatus. It is also known that Cyt1Aa, which is highly lipophilic, synergizes Cry11Aa by functioning as a surrogate membrane-bound receptor for the latter protein. Little is known, however, about whether Cyt1Aa can interact similarly with other Cry proteins not primarily mosquitocidal; for example, Cry2Aa, which is active against lepidopteran larvae, but essentially inactive or has very low toxicity to mosquito larvae. Here we demonstrate by ligand binding and enzyme-linked immunosorbent assays that Cyt1Aa and Cry2Aa form intermolecular complexes in vitro, and in addition show that Cyt1Aa facilitates binding of Cry2Aa throughout the midgut of C. quinquefasciatus larvae. As Cry2Aa and Cry11Aa share structural similarity in domain II, the interaction between Cyt1Aa and Cry2Aa could be a result of a similar mechanism previously proposed for Cry11Aa and Cyt1Aa. Finally, despite the observed interaction between Cry2Aa and Cyt1Aa, only a 2-fold enhancement in toxicity resulted against C. quinquefasciatus. Regardless, our results suggest that Cry2Aa could be a useful component of mosquitocidal endotoxin complements being developed for recombinant strains of B. thuringiensis subsp. israelensis and B. sphaericus aimed at improving the efficacy of commercial products and avoiding resistance. PMID:23727800

  5. Density and survival rate of Culex quinquefasciatus at Parque Ecológico do Tietê, São Paulo, Brazil.

    PubMed

    Laporta, Gabriel Z; Sallum, Maria Anice M

    2008-03-01

    Parity rate, gonotrophic cycle length, and density of a Culex quinquefasciatus female population was estimated at the Parque Ecológico do Tietê (PET), São Paulo, Brazil. Adult Cx. quinquefasciatus females were collected from vegetation along the edges of a polluted drainage canal with the use of a battery-powered backpack aspirator from September to November 2005 and from February to April 2006. We examined 255 Cx. quinquefasciatus ovaries to establish the parity rate of 0.22 and determined the gonotrophic cycle length under laboratory conditions to be 3 and 4 days. From these data, we calculated the Cx. quinquefasciatus survival rate to be 0.60 and 0.68 per day. Density of the Cx. quinquefasciatus female (5.71 females per m2) was estimated based on a population size of 28,810 individuals divided by the sampled area of 5,040 m2. Results of all experiments indicate medium survivorship and high density of the Cx. quinquefasciatus female population. This species is epidemiologically relevant in the PET area and should be a target of the vector control program of São Paulo municipality.

  6. Field evaluation of a dyed food marking technique for Culex quinquefasciatus (Diptera: Culicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method of marking adult Cx. quinquefasciatus Say by feeding the larvae commercial hog chow dyed with methylene blue, Giemsa, and crystal violet was evaluated under field conditions. Larvae were offered the dyed food in outdoor basins containg a mixture of dairy effluent and fresh water. Newly emer...

  7. Flushing effect of rain on container-inhabiting mosquitoes Aedes aegypti and Culex pipiens (Diptera: Culicidae).

    PubMed

    Koenraadt, C J M; Harrington, L C

    2008-01-01

    We investigated the role of heavy rain on container-inhabiting mosquito (Diptera: Culicidae) populations, and how different species may have adapted to such conditions. Rains were created with a rain simulator calibrated to natural rain intensities in the habitats of two important vector species: Aedes aegypti (L.) from northern Thailand and Culex pipiens L. from New York state, USA. Immature stages of Ae. aegypti were able to resist the flushing effect of rain better than Cx. pipiens. This difference was most dramatic during the pupal stage. Fourth instars of Ae. aegypti were not affected by flushing when exposed for longer rain intervals (30 versus 60 min) or at a colder water temperature (24 versus 16 degrees C). In contrast, significantly more Cx. pipiens larvae flushed out with longer rain exposure. Warmer water temperatures also increased the proportion of Cx. pipiens flushed out, but mostly at the longest exposure time. Container position (tilted at a 7 degrees angle or level) did not affect proportions of fourth instars flushed out for both species. More accurate models of vector-borne diseases can be developed by incorporating the described effects of rain on container-breeding mosquito populations. Such models may provide more realistic assessments of disease risk and ensure optimal use of limited financial resources of mosquito control agencies.

  8. Mitotic-Chromosome-Based Physical Mapping of the Culex quinquefasciatus Genome

    PubMed Central

    Naumenko, Anastasia N.; Timoshevskiy, Vladimir A.; Kinney, Nicholas A.; Kokhanenko, Alina A.; deBruyn, Becky S.; Lovin, Diane D.; Stegniy, Vladimir N.; Severson, David W.; Sharakhov, Igor V.; Sharakhova, Maria V.

    2015-01-01

    The genome assembly of southern house mosquito Cx. quinquefasciatus is represented by a high number of supercontigs with no order or orientation on the chromosomes. Although cytogenetic maps for the polytene chromosomes of this mosquito have been developed, their utilization for the genome mapping remains difficult because of the low number of high-quality spreads in chromosome preparations. Therefore, a simple and robust mitotic-chromosome-based approach for the genome mapping of Cx. quinquefasciatus still needs to be developed. In this study, we performed physical mapping of 37 genomic supercontigs using fluorescent in situ hybridization on mitotic chromosomes from imaginal discs of 4th instar larvae. The genetic linkage map nomenclature was adopted for the chromosome numbering based on the direct positioning of 58 markers that were previously genetically mapped. The smallest, largest, and intermediate chromosomes were numbered as 1, 2, and 3, respectively. For idiogram development, we analyzed and described in detail the morphology and proportions of the mitotic chromosomes. Chromosomes were subdivided into 19 divisions and 72 bands of four different intensities. These idiograms were used for mapping the genomic supercontigs/genetic markers. We also determined the presence of length polymorphism in the q arm of sex-determining chromosome 1 in Cx. quinquefasciatus related to the size of ribosomal locus. Our physical mapping and previous genetic linkage mapping resulted in the chromosomal assignment of 13% of the total genome assembly to the chromosome bands. We provided the first detailed description, nomenclature, and idiograms for the mitotic chromosomes of Cx. quinquefasciatus. Further application of the approach developed in this study will help to improve the quality of the southern house mosquito genome. PMID:25768920

  9. Mitotic-chromosome-based physical mapping of the Culex quinquefasciatus genome.

    PubMed

    Naumenko, Anastasia N; Timoshevskiy, Vladimir A; Kinney, Nicholas A; Kokhanenko, Alina A; deBruyn, Becky S; Lovin, Diane D; Stegniy, Vladimir N; Severson, David W; Sharakhov, Igor V; Sharakhova, Maria V

    2015-01-01

    The genome assembly of southern house mosquito Cx. quinquefasciatus is represented by a high number of supercontigs with no order or orientation on the chromosomes. Although cytogenetic maps for the polytene chromosomes of this mosquito have been developed, their utilization for the genome mapping remains difficult because of the low number of high-quality spreads in chromosome preparations. Therefore, a simple and robust mitotic-chromosome-based approach for the genome mapping of Cx. quinquefasciatus still needs to be developed. In this study, we performed physical mapping of 37 genomic supercontigs using fluorescent in situ hybridization on mitotic chromosomes from imaginal discs of 4th instar larvae. The genetic linkage map nomenclature was adopted for the chromosome numbering based on the direct positioning of 58 markers that were previously genetically mapped. The smallest, largest, and intermediate chromosomes were numbered as 1, 2, and 3, respectively. For idiogram development, we analyzed and described in detail the morphology and proportions of the mitotic chromosomes. Chromosomes were subdivided into 19 divisions and 72 bands of four different intensities. These idiograms were used for mapping the genomic supercontigs/genetic markers. We also determined the presence of length polymorphism in the q arm of sex-determining chromosome 1 in Cx. quinquefasciatus related to the size of ribosomal locus. Our physical mapping and previous genetic linkage mapping resulted in the chromosomal assignment of 13% of the total genome assembly to the chromosome bands. We provided the first detailed description, nomenclature, and idiograms for the mitotic chromosomes of Cx. quinquefasciatus. Further application of the approach developed in this study will help to improve the quality of the southern house mosquito genome.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  11. Cyt1A of Bacillus thuringiensis Delays Evolution of Resistance to Cry11A in the Mosquito Culex quinquefasciatus

    PubMed Central

    Wirth, Margaret C.; Park, Hyun-Woo; Walton, William E.; Federici, Brian A.

    2005-01-01

    Insecticides based on Bacillus thuringiensis subsp. israelensis have been used for mosquito and blackfly control for more than 20 years, yet no resistance to this bacterium has been reported. Moreover, in contrast to B. thuringiensis subspecies toxic to coleopteran or lepidopteran larvae, only low levels of resistance to B. thuringiensis subsp. israelensis have been obtained in laboratory experiments where mosquito larvae were placed under heavy selection pressure for more than 30 generations. Selection of Culex quinquefasciatus with mutants of B. thuringiensis subsp. israelensis that contained different combinations of its Cry proteins and Cyt1Aa suggested that the latter protein delayed resistance. This hypothesis, however, has not been tested experimentally. Here we report experiments in which separate C. quinquefasciatus populations were selected for 20 generations to recombinant strains of B. thuringiensis that produced either Cyt1Aa, Cry11Aa, or a 1:3 mixture of these strains. At the end of selection, the resistance ratio was 1,237 in the Cry11Aa-selected population and 242 in the Cyt1Aa-selected population. The resistance ratio, however, was only 8 in the population selected with the 1:3 ratio of Cyt1Aa and Cry11Aa strains. When the resistant mosquito strain developed by selection to the Cyt1Aa-Cry11Aa combination was assayed against Cry11Aa after 48 generations, resistance to this protein was 9.3-fold. This indicates that in the presence of Cyt1Aa, resistance to Cry11Aa evolved, but at a much lower rate than when Cyt1Aa was absent. These results indicate that Cyt1Aa is the principal factor responsible for delaying the evolution and expression of resistance to mosquitocidal Cry proteins. PMID:15640186

  12. Modeled response of the West Nile virus vector Culex quinquefasciatus to changing climate using the dynamic mosquito simulation model

    NASA Astrophysics Data System (ADS)

    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 < 0.0001). Dry environments in southern California produce different mosquito population trends than moist locations in Florida. Florida and California mosquito populations are generally temperature-limited in winter. In California, locations are water-limited through much of the year. Using future 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.

  13. Detection of an allele conferring resistance to Bacillus sphaericus binary toxin in Culex quinquefasciatus populations by molecular screening.

    PubMed

    Chalegre, Karlos Diogo de Melo; Romão, Tatiany Patrícia; Amorim, Liliane Barbosa; Anastacio, Daniela Bandeira; de Barros, Rosineide Arruda; de Oliveira, Cláudia Maria Fontes; Regis, Lêda; de-Melo-Neto, Osvaldo Pompílio; Silva-Filha, Maria Helena Neves Lobo

    2009-02-01

    The activity of the Bacillus sphaericus binary (Bin) toxin on Culex quinquefasciatus larvae depends on its specific binding to the Cqm1 receptor, a midgut membrane-bound alpha-glucosidase. A 19-nucleotide deletion in the cqm1 gene (cqm1(REC)) mediates high-level resistance to Bin toxin. Here, resistance in nontreated and B. sphaericus-treated field populations of C. quinquefasciatus was assessed through bioassays as well as a specific PCR assay designed to detect the cqm1(REC) allele in individual larvae. Resistance ratios at 90% lethal concentration, gathered through bioassays, were close to 1 and indicate that the selected populations had similar levels of susceptibility to B. sphaericus, comparable to that of a laboratory colony. A diagnostic PCR assay detected the cqm1(REC) allele in all populations investigated, and its frequency in two nontreated areas was 0.006 and 0.003, while the frequency in the B. sphaericus-treated population was significantly higher. Values of 0.053 and 0.055 were detected for two distinct sets of samples, and homozygote resistant larvae were found. Evaluation of Cqm1 expression in individual larvae through alpha-glucosidase assays corroborated the allelic frequency revealed by PCR. The data from this study indicate that the cqm1(REC) allele was present at a detectable frequency in nontreated populations, while the higher frequency in samples from the treated area is, perhaps, correlated with the exposure to B. sphaericus. This is the first report of the molecular detection of a biolarvicide resistance allele in mosquito populations, and it confirms that the PCR-based approach is suitable to track such alleles in target populations. PMID:19098223

  14. Proteolytic profiling and comparative analyses of active trypsin-like serine peptidases in preimaginal stages of Culex quinquefasciatus

    PubMed Central

    2012-01-01

    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 repertoire of proteolytic

  15. Control of human filarial vector, Culex quinquefasciatus Say 1823 (Diptera: Culicidae) through bioactive fraction of Cayratia trifolia leaf

    PubMed Central

    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

  16. Pyriproxyfen for mosquito control: female sterilization or horizontal transfer to oviposition substrates by Anopheles gambiae sensu stricto and Culex quinquefasciatus

    PubMed Central

    2014-01-01

    Background The use of gravid mosquitoes as vehicles to auto-disseminate larvicides was recently demonstrated for the transfer of pyriproxyfen (PPF) by container-breeding Aedes mosquitoes and presents an appealing idea to explore for other disease vectors. The success of this approach depends on the female’s behaviour, the time of exposure and the amount of PPF that can be carried by an individual. We explore the effect of PPF exposure at seven time points around blood feeding on individual Anopheles gambiae sensu stricto and Culex quinquefasciatus fecundity and ability to transfer in laboratory assays. Method Mosquitoes were exposed to 2.6 mg PPF per m2 at 48, 24 and 0.5 hours before and after a blood meal and on the day of egg-laying. The proportion of exposed females (N = 80-100) laying eggs, the number of eggs laid and hatched was studied. Transfer of PPF to oviposition cups was assessed by introducing 10 late instar insectary-reared An. gambiae s.s. larvae into all the cups and monitored for adult emergence inhibition. Results Exposure to PPF between 24 hours before and after a blood meal had significant sterilizing effects: females of both species were 6 times less likely (Odds ratio (OR) 0.16, 95% confidence interval (CI) 0.10-0.26) to lay eggs than unexposed females. Of the few eggs laid, the odds of an egg hatching was reduced 17 times (OR 0.06, 95% CI 0.04-0.08) in Anopheles but only 1.2 times (OR 0.82, 95% CI 0.73-0.93) in Culex. Adult emergence inhibition from larvae introduced in the oviposition cups was observed only from cups in which eggs were laid. When females were exposed to PPF close to egg laying they transferred enough PPF to reduce emergence by 65-71% (95% CI 62-74%). Conclusion PPF exposure within a day before and after blood feeding affects egg-development in An. gambiae s.s. and Cx. quinquefasciatus and presents a promising opportunity for integrated control of vectors and nuisance mosquitoes. However, sterilized females are

  17. Influence of resource levels, organic compounds, and laboratory colonization on interspecific competition between the Asian tiger mosquito (Aedes albopictus) and the southern house mosquito (Culex quinquefasciatus)

    PubMed Central

    Allgood, David W.; Yee, Donald A.

    2013-01-01

    The mosquitoes Aedes albopictus (Skuse) and Culex quinquefasciatus (Say) (Diptera:Culicidae) are common inhabitants of tyres and other artificial containers, which constitute important peridomestic mosquito breeding habitats. We tested the hypotheses that interspecific resource competition between the larvae of these species is asymmetrical, that the concentration of chemicals associated with decomposing detritus affects their competitive outcome, and that wild and colonized strains of Cx. quinquefasciatus are affected differently by competition with Ae. albopictus. We conducted two laboratory competition experiments wherein we measured survivorship and estimated population growth (λ’) of both species under multiple mixed-species densities. Under varying resource levels, competition was asymmetrical with Ae. albopictus causing competitive reductions or exclusions of Cx. quinquefasciatus under limited resources. In a second experiment, which used both wild and colonized strains of Cx. quinquefasciatus, organic chemical compounds associated with decomposing detritus did not affect the competitive outcome. The colonized strain of Cx. quinquefasciatus had greater survivorship, adult mass, and faster development times than the wild strain, but both strains were similarly affected by competition with Ae. albopictus. Competition between these species may have important consequences for vector population dynamics, especially in areas where tyres and artificial containers constitute the majority of mosquito breeding habitats. PMID:24444185

  18. Interspecific competition of a new invasive mosquito, Culex coronator, and two container mosquitoes, Aedes albopictus and Cx. quinquefasciatus (Diptera: Culicidae), across different detritus environments.

    PubMed

    Yee, D A; Skiff, J F

    2014-01-01

    The mosquito Culex coronator (Dyar and Knab) (Diptera: Culicidae) has undergone rapid range expansion in the United States since 2003, with its historical distribution in the southwest expanding eastward to the Atlantic coast. Although Cx. coronator nominally use small natural aquatic habitats for development, the use of containers (e.g., tires) makes it potentially important as container invasive. To determine the potential ecological effects of Cx. coronator on resident container species, we conducted a laboratory experiment to assess its competitive ability with two common tire-inhabiting species, Aedes albopictus (Skuse) and Culex quinquefasciatus (Say) (Diptera: Culicidae). Larvae were reared under a factorial design with each species alone and in combination (Cx. coronator + Ae. albopictus, Cx. coronator + Cx. quinquefasciatus) across three different resource environments (leaf detritus only, animal detritus only, animal + leaf). Mosquito performance (survival, adult male and female mass, and development time) was measured for each species across treatments. Female Cx. coronator developed slowest when grown with Ae. albopictus, or when grown with leaves only regardless of species combinations; similar patterns emerged for males although species effects were restricted to mass. Few differences were evident in performance for male and female Cx. coronator across detritus environments when grown with Cx. quinquefasciatus. Cx. quinquefasciatus did not vary in mass or development time in the presence of Cx. coronator compared with when grown alone. Ae. albopictus female mass was 15% lower in the presence of Cx. coronator. Survival of Cx. coronator was highest in animal and leaf detritus containers, although survival was generally lower when larvae were grown with Ae. albopictus. These findings suggest that the performance of Cx. coronator is similar to that of Cx. quinquefasciatus but it suffers in the presence of Ae. albopictus under some resource environments.

  19. Histopathological effects of Aspergillus clavatus (Ascomycota: Trichocomaceae) on larvae of the southern house mosquito, Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Bawin, Thomas; Seye, Fawrou; Boukraa, Slimane; Zimmer, Jean-Yves; Raharimalala, Fara Nantenaina; Ndiaye, Mady; Compere, Philippe; Delvigne, Frank; Francis, Frédéric

    2016-04-01

    Aspergillus clavatus (Ascomycota: Trichocomaceae) was previously found to be an opportunistic pathogen of mosquitoes (Diptera: Culicidae). In the present study, the mechanism leading to its insecticidal activity was investigated regarding histological damages on Culex quinquefasciatus larvae exposed to A. clavatus spores. Multiple concentration assays using spore suspensions (0.5-2.5 × 10(8) spores ml(-1)) revealed 17.0-74.3 % corrected mortalities after 48 h exposure. Heat-deactivated spores induced a lower mortality compared to nonheated spores suggesting that insecticidal effects are actively exerted. Spore-treated and untreated larvae were prepared for light microscopy as well as for scanning and transmission electron microscopy. Spores failed to adhere to the external body surface (except the mouth parts) of these aquatic immature stages but progressively filled the digestive tract where their metabolism seemed to activate. In parallel, the internal tissues of the larvae, i.e. the midgut wall, the skeletal muscles, and the cuticle-secreting epidermis, were progressively destroyed between 8 and 24 h of exposure. These observations suggest that toxins secreted by active germinating spores of A. clavatus in the digestive tract altered the larval tissues, leading to their necrosis and causing larval death. Fungal proliferation and sporulation then occurred during a saprophytic phase. A. clavatus enzymes or toxins responsible for these pathogenic effects need to be identified in further studies before any use of this fungus in mosquito control. PMID:27020151

  20. Location of and landing on a source of human body odour by female Culex quinquefasciatus in still and moving air

    PubMed Central

    LACEY, EMERSON S.; CARDÉ, RING T.

    2014-01-01

    The orientation to and landing on a source of human odour by female Culex quinquefasciatus Say (Diptera: Culicidae) is observed in a wind tunnel without an airflow or with a laminar airflow of 0.2 m s-1. Odours from human feet are collected by ‘wearing’ clean glass beads inside a stocking and presenting beads in a Petri dish in a wind tunnel. Mosquitoes are activated by brief exposure to a 1 L min-1 jet of 4% CO2 positioned 10 cm from the release cage. In moving air at 0.2 m s-1, a mean of 3.45 ± 0.49 landings are observed in 10 min trials (5 mosquitoes per trial), whereas 6.50 ± 0.96 landings are recorded in still air. Furthermore, 1.45 ± 0.31mosquitoes are recorded on beads at any one time in moving air (a measure of individuals landing versus one landing multiple times) compared to 3.10 ± 0.31 in still air. Upwind flight to beads in moving air is demonstrated by angular headings of flight immediately prior to landing, whereas approaches to beads in still air are oriented randomly. The mean latency until first landing is 226.7 ± 17.98 s in moving air compared to 122.5 ± 24.18 in still air. Strategies used to locate a prospective host at close range in still air are considered. PMID:26472918

  1. Some observations on overwintering sites of adult Culex quinquefasciatus (Diptera: Culicidae) and strategies followed under natural and seminatural conditions.

    PubMed

    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.

  2. Histopathological effects of Aspergillus clavatus (Ascomycota: Trichocomaceae) on larvae of the southern house mosquito, Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Bawin, Thomas; Seye, Fawrou; Boukraa, Slimane; Zimmer, Jean-Yves; Raharimalala, Fara Nantenaina; Ndiaye, Mady; Compere, Philippe; Delvigne, Frank; Francis, Frédéric

    2016-04-01

    Aspergillus clavatus (Ascomycota: Trichocomaceae) was previously found to be an opportunistic pathogen of mosquitoes (Diptera: Culicidae). In the present study, the mechanism leading to its insecticidal activity was investigated regarding histological damages on Culex quinquefasciatus larvae exposed to A. clavatus spores. Multiple concentration assays using spore suspensions (0.5-2.5 × 10(8) spores ml(-1)) revealed 17.0-74.3 % corrected mortalities after 48 h exposure. Heat-deactivated spores induced a lower mortality compared to nonheated spores suggesting that insecticidal effects are actively exerted. Spore-treated and untreated larvae were prepared for light microscopy as well as for scanning and transmission electron microscopy. Spores failed to adhere to the external body surface (except the mouth parts) of these aquatic immature stages but progressively filled the digestive tract where their metabolism seemed to activate. In parallel, the internal tissues of the larvae, i.e. the midgut wall, the skeletal muscles, and the cuticle-secreting epidermis, were progressively destroyed between 8 and 24 h of exposure. These observations suggest that toxins secreted by active germinating spores of A. clavatus in the digestive tract altered the larval tissues, leading to their necrosis and causing larval death. Fungal proliferation and sporulation then occurred during a saprophytic phase. A. clavatus enzymes or toxins responsible for these pathogenic effects need to be identified in further studies before any use of this fungus in mosquito control.

  3. Inheritance and mechanism of resistance to Bacillus sphaericus in Culex quinquefasciatus (Diptera: Culicidae) from China and Brazil.

    PubMed

    Oliveira, Cláudia M F; Silva-Filha, Maria Helena; Nielsen-Leroux, Christina; Pei, Guofeng; Yuan, Zhiming; Regis, Lêda

    2004-01-01

    Investigations on the inheritance and mechanism of resistance to Bacillus sphaericus Neide in Culex quinquefasciatus Say colonies, selected with strains C3-41 (RLCq1/C3-41) and 2362 (CqRL1/2362), were performed in China and Brazil, respectively. The progeny of reciprocal F1 crosses (susceptible female x resistant male and vice versa) from both resistant colonies responded alike in bioassays, indicating recessive inheritance. Data on larvae susceptibility from the backcross offspring between F1 and their respective susceptible and resistant parental colonies are consistent with a monofactorial and autosomal mode of inheritance. In vitro binding assays between 125I binary (Bin2) toxin and the brush border membrane fractions (BBMF) from CqRL1/2362 and RLCq1/C3-41 larvae showed that resistance, in both colonies, is caused by a failure in the binding step of the B. sphaericus Bin2 toxin to its specific midgut receptor. The specific and saturable binding of Bin2 toxin to BBMF from F1 larvae (CqRL1/2362 X susceptible counterpart) confirms the recessive inheritance of the resistance gene. Further studies are needed to advance understanding of B. sphaericus resistance. PMID:14989346

  4. Novel mutations associated with resistance to Bacillus sphaericus in a polymorphic region of the Culex quinquefasciatus cqm1 gene.

    PubMed

    Chalegre, Karlos Diogo de Melo; Romão, Tatiany Patrícia; Tavares, Daniella Aliny; Santos, Eloína Mendonça; Ferreira, Lígia Maria; Oliveira, Cláudia Maria Fontes; de-Melo-Neto, Osvaldo Pompílio; Silva-Filha, Maria Helena Neves Lobo

    2012-09-01

    Bin toxin from Bacillus sphaericus acts on Culex quinquefasciatus larvae by binding to Cqm1 midgut-bound receptors, and disruption of the cqm1 gene is the major cause of resistance. The goal of this work was to screen for a laboratory-selected resistance cqm1(REC) allele in field populations in the city of Recife, Brazil, and to describe other resistance-associated polymorphisms in the cqm1 gene. The cqm1(REC) allele was detected in the four nontreated populations surveyed at frequencies from 0.001 to 0.017, and sequence analysis from these samples revealed a novel resistant allele (cqm1(REC-D16)) displaying a 16-nucletotide (nt) deletion which is distinct from the 19-nt deletion associated with cqm1(REC). Yet a third resistant allele (cqm1(REC-D25)), displaying a 25-nt deletion, was identified in samples from a treated area exposed to B. sphaericus. A comparison of the three deletion events revealed that all are located within the same 208-nt region amplified during the screening procedure. They also introduce equivalent frameshifts in the sequence and generate the same premature stop codon, leading to putative transcripts encoding truncated proteins which are unable to locate to the midgut epithelium. The populations analyzed in this study contained a variety of alleles with mutations disrupting the function of the corresponding Bin toxin receptor. Their locations reveal a hot spot that can be exploited to assess the resistance risk through DNA screening. PMID:22773633

  5. Culex Species Mosquitoes and Zika Virus.

    PubMed

    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.

  6. Culex Species Mosquitoes and Zika Virus.

    PubMed

    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. PMID:27556838

  7. Study of the effect of the midgut bacterial flora of Culex quinquefasciatus on the susceptibility of mosquitoes to Japanese encephalitis virus.

    PubMed

    Mourya, D T; Gokhale, M D; Pidiyar, V; Barde, P V; Patole, M; Mishra, A C; Shouche, Y

    2002-01-01

    Culex quinquefasciatus mosquitoes were collected from the field and microbial flora was isolated from their midgut. Isolates belonging to 13 different genera were obtained. Four most abundant isolates viz. Pseudomonas sp., Acinetobacterjunii, Staphylococcus epidermis and Aeromonas culicicola were used to study their effect on the susceptibility of mosquitoes to Japanese encephalitis virus (JEV). Incorporation of individual isolates in the mosquito bloodmeal resulted in an increased susceptibility of mosquitoes to the virus. However, only the effects of Pseudomonas sp. and Acinetobacterjunii could be statistically evaluated but they were found insignificant. PMID:12693864

  8. [Aedes (Stegomyia) aegypti L. and associated culicidae fauna in a urban area of southern Brazil].

    PubMed

    Lopes, J; da Silva, M A; Borsato, A M; de Oliveira, V D; Oliveira, F J

    1993-10-01

    Some aspects of the ecology of eleven species of Culicidae that were found breeding in recipients in an urban area of Southern Brazil are presented. A great variety of recipients were listed as efficient breeding sites. Apparently Aedes aegypti has been recently introduced into the region and was limited to two areas of the city. Culex quinquefasciatus, Cx. coronator, Ae. aegypti, Ae. fluviatilis e Limatus durhamii were the predominant species.

  9. Larvicidal efficacy of various formulations of Bacillus sphaericus against the resistant strain of Culex quinquefasciatus (Diptera: Culicidae) from southern India.

    PubMed

    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.

  10. Point mutations associated with organophosphate and carbamate resistance in Chinese strains of Culex pipiens quinquefasciatus (Diptera: Culicidae).

    PubMed

    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.

  11. Toxicity of seaweed-synthesized silver nanoparticles against the filariasis vector Culex quinquefasciatus and its impact on predation efficiency of the cyclopoid crustacean Mesocyclops longisetus.

    PubMed

    Murugan, Kadarkarai; Benelli, Giovanni; Ayyappan, Suganya; Dinesh, Devakumar; Panneerselvam, Chellasamy; Nicoletti, Marcello; Hwang, Jiang-Shiou; Kumar, Palanisamy Mahesh; Subramaniam, Jayapal; Suresh, Udaiyan

    2015-06-01

    Nearly 1.4 billion people in 73 countries worldwide are threatened by lymphatic filariasis, a parasitic infection that leads to a disease commonly known as elephantiasis. Filariasis is vectored by mosquitoes, with special reference to the genus Culex. The main control tool against mosquito larvae is represented by treatments with organophosphates and insect growth regulators, with negative effects on human health and the environment. Recently, green-synthesized nanoparticles have been proposed as highly effective larvicidals against mosquito vectors. In this research, we attempted a reply to the following question: do green-synthesized nanoparticles affect predation rates of copepods against mosquito larvae? We proposed a novel method of seaweed-mediated synthesis of silver nanoparticles using the frond extract of Caulerpa scalpelliformis. The toxicity of the seaweed extract and silver nanoparticles was assessed against the filarial vector Culex quinquefasciatus. Then, we evaluated the predatory efficiency of the cyclopoid crustacean Mesocyclops longisetus against larval instars of C. quinquefasciatus in a nanoparticle-contaminated water environment. Green-synthesized silver nanoparticles were characterized by UV-vis spectrum, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). In mosquitocidal assays, the LC₅₀ values of the C. scalpelliformis extract against C. quinquefasciatus were 31.38 ppm (I), 46.49 ppm (II), 75.79 ppm (III), 102.26 ppm (IV), and 138.89 ppm (pupa), while LC₅₀ of silver nanoparticles were 3.08 ppm, (I), 3.49 ppm (II), 4.64 ppm (III), 5.86 ppm (IV), and 7.33 ppm (pupa). The predatory efficiency of the copepod M. longisetus in the control treatment was 78 and 59% against I and II instar larvae of C. quinquefasciatus. In a nanoparticle-contaminated environment, predation efficiency was 84 and 63%, respectively. Predation was higher against first instar larvae over other instars

  12. Climate Change Influences on the Global Potential Distribution of the Mosquito Culex quinquefasciatus, Vector of West Nile Virus and Lymphatic Filariasis

    PubMed Central

    Elaagip, Arwa H.; Kenawy, Mohamed A.; Ayres, Constância F. J.; Peterson, A. Townsend; Soliman, Doaa E.

    2016-01-01

    Rapid emergence of most vector-borne diseases (VBDs) may be associated with range expansion of vector populations. Culex quinquefasciatus Say 1823 is a potential vector of West Nile virus, Saint Louis encephalitis virus, and lymphatic filariasis. We estimated the potential distribution of Cx. quinquefasciatus under both current and future climate conditions. The present potential distribution of Cx. quinquefasciatus showed high suitability across low-latitude parts of the world, reflecting the current distribution of the species. Suitable conditions were identified also in narrow zones of North Africa and Western Europe. Model transfers to future conditions showed a potential distribution similar to that under present-day conditions, although with higher suitability in southern Australia. Highest stability with changing climate was between 30°S and 30°N. The areas present high agreement among diverse climate models as regards distributional potential in the future, but differed in anticipating potential for distribution in North and Central Africa, southern Asia, central USA, and southeastern Europe. Highest disparity in model predictions across representative concentration pathways (RCPs) was in Saudi Arabia and Europe. The model predictions allow anticipation of changing distributional potential of the species in coming decades. PMID:27695107

  13. Characterisation of Culex quinquefasciatus (Diptera: Culicidae) larval habitats at ground level and temporal fluctuations of larval abundance in Córdoba, Argentina.

    PubMed

    Grech, Marta; Sartor, Paolo; Estallo, Elizabet; Ludueña-Almeida, Francisco; Almirón, Walter

    2013-09-01

    The aims of this study were to characterise the ground-level larval habitats of the mosquito Culex quinquefasciatus, to determine the relationships between habitat characteristics and larval abundance and to examine seasonal larval-stage variations in Córdoba city. Every two weeks for two years, 15 larval habitats (natural and artificial water bodies, including shallow wells, drains, retention ponds, canals and ditches) were visited and sampled for larval mosquitoes. Data regarding the water depth, temperature and pH, permanence, the presence of aquatic vegetation and the density of collected mosquito larvae were recorded. Data on the average air temperatures and accumulated precipitation during the 15 days prior to each sampling date were also obtained. Cx. quinquefasciatus larvae were collected throughout the study period and were generally most abundant in the summer season. Generalised linear mixed models indicated the average air temperature and presence of dicotyledonous aquatic vegetation as variables that served as important predictors of larval densities. Additionally, permanent breeding sites supported high larval densities. In Córdoba city and possibly in other highly populated cities at the same latitude with the same environmental conditions, control programs should focus on permanent larval habitats with aquatic vegetation during the early spring, when the Cx. quinquefasciatus population begins to increase. PMID:24037200

  14. Carbon and silver nanoparticles in the fight against the filariasis vector Culex quinquefasciatus: genotoxicity and impact on behavioral traits of non-target aquatic organisms.

    PubMed

    Murugan, Kadarkarai; Nataraj, Devaraj; Madhiyazhagan, Pari; Sujitha, Vasu; Chandramohan, Balamurugan; Panneerselvam, Chellasamy; Dinesh, Devakumar; Chandirasekar, Ramachandran; Kovendan, Kalimuthu; Suresh, Udaiyan; Subramaniam, Jayapal; Paulpandi, Manickam; Vadivalagan, Chithravel; Rajaganesh, Rajapandian; Wei, Hui; Syuhei, Ban; Aziz, Al Thabiani; Alsalhi, Mohamad Saleh; Devanesan, Sandhanasamy; Nicoletti, Marcello; Canale, Angelo; Benelli, Giovanni

    2016-03-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. The Culex genus, with special reference to Culex quinquefasciatus, comprises the most common vectors of filariasis across urban and semi-urban areas of Asia. In recent years, important efforts have been conducted to propose green-synthesized nanoparticles as a valuable alternative to synthetic insecticides. However, the mosquitocidal potential of carbon nanoparticles has been scarcely investigated. In this study, the larvicidal and pupicidal activity of carbon nanoparticle (CNP) and silver nanoparticle (AgNP) was tested against Cx. quinquefasciatus. UV-Vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, and Raman analysis confirmed the rapid and cheap synthesis of carbon and silver nanoparticles. In laboratory assays, LC50 (lethal concentration that kills 50 % of the exposed organisms) values ranged from 8.752 ppm (first-instar larvae) to 18.676 ppm (pupae) for silver nanoparticles and from 6.373 ppm (first-instar larvae) to 14.849 ppm (pupae) for carbon nanoparticles. The predation efficiency of the water bug Lethocerus indicus after a single treatment with low doses of silver and carbon nanoparticles was not reduced. Moderate evidence of genotoxic effects induced by exposure to carbon nanoparticles was found on non-target goldfish, Carassius auratus. Lastly, the plant extract used for silver nanosynthesis was tested for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity. Overall, our results pointed out that AgNP and CNP can be a candidate for effective tools to reduce larval and pupal populations of filariasis vectors, with reduced genotoxicity and impact on behavioral traits of other aquatic organisms sharing the same ecological

  15. Carbon and silver nanoparticles in the fight against the filariasis vector Culex quinquefasciatus: genotoxicity and impact on behavioral traits of non-target aquatic organisms.

    PubMed

    Murugan, Kadarkarai; Nataraj, Devaraj; Madhiyazhagan, Pari; Sujitha, Vasu; Chandramohan, Balamurugan; Panneerselvam, Chellasamy; Dinesh, Devakumar; Chandirasekar, Ramachandran; Kovendan, Kalimuthu; Suresh, Udaiyan; Subramaniam, Jayapal; Paulpandi, Manickam; Vadivalagan, Chithravel; Rajaganesh, Rajapandian; Wei, Hui; Syuhei, Ban; Aziz, Al Thabiani; Alsalhi, Mohamad Saleh; Devanesan, Sandhanasamy; Nicoletti, Marcello; Canale, Angelo; Benelli, Giovanni

    2016-03-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. The Culex genus, with special reference to Culex quinquefasciatus, comprises the most common vectors of filariasis across urban and semi-urban areas of Asia. In recent years, important efforts have been conducted to propose green-synthesized nanoparticles as a valuable alternative to synthetic insecticides. However, the mosquitocidal potential of carbon nanoparticles has been scarcely investigated. In this study, the larvicidal and pupicidal activity of carbon nanoparticle (CNP) and silver nanoparticle (AgNP) was tested against Cx. quinquefasciatus. UV-Vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, and Raman analysis confirmed the rapid and cheap synthesis of carbon and silver nanoparticles. In laboratory assays, LC50 (lethal concentration that kills 50 % of the exposed organisms) values ranged from 8.752 ppm (first-instar larvae) to 18.676 ppm (pupae) for silver nanoparticles and from 6.373 ppm (first-instar larvae) to 14.849 ppm (pupae) for carbon nanoparticles. The predation efficiency of the water bug Lethocerus indicus after a single treatment with low doses of silver and carbon nanoparticles was not reduced. Moderate evidence of genotoxic effects induced by exposure to carbon nanoparticles was found on non-target goldfish, Carassius auratus. Lastly, the plant extract used for silver nanosynthesis was tested for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity. Overall, our results pointed out that AgNP and CNP can be a candidate for effective tools to reduce larval and pupal populations of filariasis vectors, with reduced genotoxicity and impact on behavioral traits of other aquatic organisms sharing the same ecological

  16. Acute toxicity and synergistic and antagonistic effects of the aromatic compounds of some essential oils against Culex quinquefasciatus Say larvae.

    PubMed

    Pavela, Roman

    2015-10-01

    The efficacy of 30 aromatic compounds and their mutual binary combinations was assessed for acute toxicity against the larvae Culex quinquefasciatus. Based on comparison of the lethal doses, thymol and p-cymene were selected as the most effective (LD50 = 18 and 21 mg L(-1), respectively, and LD90 = 25 and 30 mg L(-1), respectively). Although the LD50 for terpinolene and trans-anethole was also estimated at 21 mg L(-1), their LD90 was significantly higher compared to the substances above (245 and 34 mg L(-1), respectively). In total, 435 binary combinations were tested, of which 249 combinations showed a significant synergistic effect, while 74 combinations showed a significant antagonistic effect on mortality. Only nine substances were identified as being able to create a synergistic effect with more than 20 substances: limonene, trans-anethole, 4-allylanisole, carvacrol, isoeugenol, menthone, carvone, borneol, and camphor. The highest synergistic effect on larval mortality was achieved for the combinations: eugenol and isoeugenol, carvone and carvacrol, carvone and 4-allylanisole, carvone and α-terpineol, carvone and menthone, limonene and trans-anethole, limonene and menthone, α-pinene and menthone, β-citronellol and menthone, carvacrol and 4-allylanisole, carvacrol and terpineol, α-terpinene and trans-anethole, camphor and menthone, camphene and menthone, and 4-allylanisole and menthone. Significant differences between achieved mortality and the mutual mixing ratio were found for the five selected binary mixtures that had shown the most significant synergistic effect in the previous tests. The mixture of limonene and trans-anethole showed the highest mortality, with the mixing ratio 1:1; the mixture of eugenol and isoeugenol caused 90.2% mortality, with the mixing ratio 1:3. One hundred percent mortality was achieved if carvacrol was contained in a mixture with carvone in a ratio >2. After a comparison of all our results, based on our experiments, we

  17. Insecticidal activity of isobutylamides derived from Piper nigrum against adult of two mosquito species, Culex pipiens pallens and Aedes aegypti.

    PubMed

    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/♀.

  18. Mosquito control in Dar es Salaam. II. Impact of expanded polystyrene beads and pyriproxyfen treatment of breeding sites on Culex quinquefasciatus densities.

    PubMed

    Chavasse, D C; Lines, J D; Ichimori, K; Majala, A R; Minjas, J N; Marijani, J

    1995-04-01

    In two contrasting areas of Dar es Salaam (Ilala and Mikocheni) all enclosed breeding sites of Culex quinquefasciatus, such as latrines and septic tanks, were treated with a floating layer of expanded polystyrene beads. 7 months later checks in both study areas revealed only one site (from which the polystyrene had been removed during emptying) containing immature stages of Cx quinquefasciatus. Open breeding sites such as areas of flooded land and blocked drains were treated with pyriproxyfen (an insect growth regulator) at a concentration of 0.1 ppm. Emergence of Cx quinquefasciatus adults from these sites was inhibited for 4 weeks during the rainy season and for up to 11 weeks during the dry season. The problem of mosquito breeding sites caused by bathroom sullage water was addressed through a combination of health education and indirect pressure from the Urban Malaria Control Project (UMCP) via local community leaders. Households responsible for these sites were encouraged to eliminate them by diverting the water into an enclosed drainage structure, usually a pit latrine. After two weekly visits 64.7% of households had complied and 93.4% had complied after five visits. 5 months later, only 15.7% had reverted to allowing sullage water to collect into puddles. Densities of Cx quinquefasciatus adults dropped by 76.7% in Mikocheni and by 46.2% in Ilala following intervention, but increased by 84.9% and 25.6% in two untreated comparison areas. The reasons for differential success of the combined interventions in the two treated areas are discussed.

  19. Larval habitat for the avian malaria vector culex quinquefasciatus (Diptera: Culicidae) in altered mid-elevation mesic-dry forests in Hawai'i

    USGS Publications Warehouse

    Reiter, M.E.; Lapointe, D.A.

    2009-01-01

    Effective management of avian malaria (Plasmodium relictum) in Hawai'i's endemic honeycreepers (Drepanidinae) requires the identification and subsequent reduction or treatment of larval habitat for the mosquito vector, Culex quinquefasciatus (Diptera: Culicidae). We conducted ground surveys, treehole surveys, and helicopter aerial surveys from 20012003 to identify all potential larval mosquito habitat within two 100+ ha mesic-dry forest study sites in Hawai'i Volcanoes National Park, Hawai'i; 'Ainahou Ranch and Mauna Loa Strip Road. At 'Ainahou Ranch, anthropogenic sites (43%) were more likely to contain mosquitoes than naturally occurring (8%) sites. Larvae of Cx. quinquefasciatus were predominately found in anthropogenic sites while Aedes albopictus larvae occurred less frequently in both anthropogenic sites and naturally-occurring sites. Additionally, moderate-size (???20-22,000 liters) anthropogenic potential larval habitat had >50% probability of mosquito presence compared to larger- and smaller-volume habitat (<50%). Less than 20% of trees surveyed at ' Ainahou Ranch had treeholes and few mosquito larvae were detected. Aerial surveys at 'Ainahou Ranch detected 56% (95% CI: 42-68%) of the potential larval habitat identified in ground surveys. At Mauna Loa Strip Road, Cx. quinquefasciatus larvae were only found in the rock holes of small intermittent stream drainages that made up 20% (5 of 25) of the total potential larval habitat. The volume of the potential larval habitat did not influence the probability of mosquito occurrence at Mauna Loa Strip Road. Our results suggest that Cx. quinquefasciatus abundance, and subsequently avian malaria, may be controlled by larval habitat reduction in the mesic-dry landscapes of Hawai'i where anthropogenic sources predominate.

  20. Bioefficacy of a long-lasting insecticide impregnated net on blood feeding inhibition of Anopheles maculatus Theobald and Culex quinquefasciatus Say.

    PubMed

    Beng, Tan Swee; Vythilingam, Indra; Lim, Lee Han

    2014-05-01

    This study aimed to evaluate the bioefficacy and blood feeding inhibition of mosquitoes under laboratory conditions using the WHO tunnel test method on unwashed and washed long-lasting insecticide impregnated net with extrinsic heat treatment of 30 degrees C followed by 80 degrees C on the same net during washing. PermaNet exhibited fairy high durability to washing (5 washes) and had fairy long-lasting bioefficacy against Anopheles maculatus for blood feeding inhibition on both unwashed (39 months) and washed (26 months) nets. However, Perma-Net exhibited lower bioefficacy against Culex quinquefasciatus. This study also suggested that the application of extrinsic heat treatment of 30 degrees C followed by an increased heat at 80 degrees C on the same net exerted significant differences (p < 0.05) in mortality of both An. maculatus and Cx. quinquefasciatus. However, extrinsic heat treatment did not enhance any significant increase in blood feeding inhibition of both An. maculatus and Cx. quinquefasciatus (p > 0.05). An. maculatus exhibited significant differences in resting preference after a successful blood meal, as more blood-fed and live females preferred to rest and stay near the bait in the mouse cage, and more dead and unfed females were found in the outer cage of both the unwashed and washed nets (p < 0.05). Conversely, fully blood-fed and live Cx. quinquefasciatus females did not show any resting preference between the mouse cage and outer cage, but there were more dead and unfed females in the mouse cage of both the unwashed and washed nets (p < 0.05).

  1. Inheritance, stability, and dominance of cry resistance in Culex quinquefasciatus (Diptera: Culicidae) selected with the three cry toxins of Bacillus thuringiensis subsp. israelensis.

    PubMed

    Wirth, Margaret C; Walton, William E; Federici, Brian A

    2012-07-01

    Mendelian crosses were used to study the mode of inheritance of Cry toxin resistance in a Culex quinquefasciatus Say (Diptera: Culicidae) colony (CqAB11A) that evolved insecticide resistance under laboratory selection with a deletion mutant of Bacillus thuringiensis subsp. israelensis de Barjac lacking the Cyt1Aa toxin component but containing its three major Cry toxins, Cry4Aa, Cry4Ba, and Cry11Aa. High levels of resistance were observed to Cry toxins. F1 offspring of reciprocal crosses to a sensitive colony showed intermediate levels of resistance with no maternal effect, indicating autosomal inheritance. Dose-response data for backcross offspring deviated significantly from the monofactorial model when tested with Cry4Aa + Cry4Ba + Cry11Aa, Cry4Aa + Cry4Ba, or Cry11Aa. However, tests with Cry11Ba from B. thuringiensis subsp. jegathesan (Seleena, Lee, Lecadet) fit the monofactorial model. Dominance of F1 offspring was calculated at different concentrations of Cry-toxin suspensions and, as reported for other Cry-resistant Culex, generally decreased as concentration increased. A subset of colony CqAB11A was reared without selection pressure for 18 generations with little change in susceptibility, indicating a highly homozygous population. Consistent with reports for other Cry-resistant Culex, the data show these mosquitoes evolved resistance to B. thuringiensis Cry toxins at multiple loci in response to selection pressure and that cross-resistance to Cry11Ba was conferred by one of those loci.

  2. A study of population changes in adult Culex quinquefasciatus Say (Diptera: Culicidae) during a mosquito control programme in Dubai, United Arab Emirates.

    PubMed

    Holmes, P R

    1986-02-01

    The effectiveness of insecticidal control measures on adult Culex quinquefasciatus Say in Dubai, United Arab Emirates, was examined. Direct treatment of the study site with cypermethrin applied as a fog caused a temporary reduction both in total numbers (males and females) and in the proportion of older females. When cypermethrin was applied as an ultra low volume formulation at dusk and dawn numbers of males were greatly reduced, but numbers of females were not affected. It appears that the adulticiding operations had little overall effect on the total numbers or survival rate of females, or breeding success. The oviposition cycle duration was estimated to be two days, with the survival rate per oviposition cycle calculated as 30%. With these values it is thought unlikely that filariasis would be transmitted in Dubai.

  3. Evaluation of aqueous and ethanol extract of bioactive medicinal plant, Cassia didymobotrya (Fresenius) Irwin & Barneby against immature stages of filarial vector, Culex quinquefasciatus Say (Diptera: Culicidae)

    PubMed Central

    Nagappan, Raja

    2012-01-01

    Objective To evaluate aqueous and ethanol extract of Cassia didymobotrya leaves against immature stages of Culex quinquefasciatus. Methods The mortality rate of immature mosquitoes was tested in wide and narrow range concentration of the plant extract based on WHO standard protocol. The wide range concentration tested in the present study was 10 000, 1 000, 100, 10 and 1 mg/L and narrow range concentration was 50, 100, 150, 200 and 250 mg/L. Results 2nd instar larvae exposed to 100 mg/L and above concentration of ethanol extract showed 100% mortality. Remaining stages such as 3rd, 4th and pupa, 100% mortality was observed at 1 000 mg/L and above concentration after 24 h exposure period. In aqueous extract all the stages 100% mortality was recorded at 1 000 mg/L and above concentration. In narrow range concentration 2nd instar larvae 100% mortality was observed at 150 mg/L and above concentration of ethanol extract. The remaining stages 100% mortality was recorded at 250 mg/L. In aqueous extract all the tested immature stages 100% mortality was observed at 250 mg/L concentration after 24 h exposure period. The results clearly indicate that the rate of mortality was based dose of the plant extract and stage of the mosquitoes. Conclusions From this study it is confirmed and concluded that Cassia didymobotrya is having active principle which is responsible for controlling Culex quinquefasciatus. The isolation of bioactive molecules and development of simple formulation technique is important for large scale implementation. PMID:23569999

  4. Evolution of resistance toward Bacillus sphaericus or a mixture of B. sphaericus+Cyt1A from Bacillus thuringiensis, in the mosquito, Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Wirth, Margaret C; Jiannino, Joshua A; Federici, Brian A; Walton, William E

    2005-02-01

    The 2362 strain of Bacillus sphaericus (Bs) Neide is a highly mosquitocidal bacterium used in commercial bacterial larvicides primarily to control mosquitoes of the genus Culex. Unfortunately, Bs is at high risk for selecting resistance in mosquito populations, because its binary toxin apparently only binds to a single receptor type on midgut microvilli. A potential key strategy for delaying resistance to insecticidal proteins is to use mixtures of toxins that act at different targets within the insect, especially mixtures that interact synergistically. We tested this hypothesis for delaying the phenotypic expression of resistance by exposing Culex quinquefasciatus Say larvae to Bs alone or in combination with Cyt1A from Bacillus thuringiensis subsp. israelensis. Two laboratory lines of Cx. quinquefasciatus, one sensitive to Bs and the other containing Bs resistance alleles, were subjected to intensive selection pressure for 20 generations with either Bs 2362 or a 3:1 mixture of Bs 2362+Cyt1A. At the end of the study, the sensitive line had evolved >1000-fold resistance when selected with Bs alone, whereas the parallel line selected with Bs+Cyt1A exhibited only low resistance toward this mixture (RR95, 1.4). Similar results were observed in the lines containing Bs resistance alleles. Both lines selected with Bs+Cyt1A exhibited substantial resistance to Bs in the absence of Cyt1A. Although selection with Bs+Cyt1A did not prevent the underlying evolution of resistance to Bs, these results suggest that a mixture of Bs with other endotoxins, particularly one like Bs+Cyt1A in which the components interact synergistically, will provide longer lasting and more effective mosquito control than Bs alone. PMID:15766932

  5. Anti-juvenile activity of Azadirachta indica extract on the development and morphometry of filaria vector, Culex quinquefasciatus (Diptera: Culicidae) Say.

    PubMed

    Sharma, Preeti; Mohan, Lalit; Srivastava, Chand N

    2009-10-01

    Efficacy of extracts of Ageratum conyzoides, Argemone mexicana, and Azadirachta indica were tested against Culex quinquefasciatus larvae. Petroleum ether extracts of A. conyzoides and A. mexicana with LC(50) values 425.60 and 267.90 ppm and 140.15 and 137.70 ppm after a period of 24 and 48 h, respectively, were found effective. However, the methanol extract of A. indica with LC(50) values 21.95 and 11.30 ppm after 24 and 48 h of exposure, respectively, was the most competent larvicide. The methanol extract of A. indica, being the most potent extract was therefore studied for its impact on the developmental scenario of the mosquito. It had a significant effect on the life cycle of the vector, C. quinquefasciatus. Hatching was delayed and its rate was reduced compared to control. Larval and pupal development was arrested resulting in decreased pupal transformation and adult emergence. Larval and pupal periods were prolonged with appearance of larval-pupal and pupal-adult intermediates, with an overall increase in the developmental period. Disrupted egg shells, dechitinized body walls, and distorted intestines were observed, indicating clearly the anti-juvenile potential of the extract. The growth index was considerably reduced.

  6. Effects of ultra-low volume and thermal fog malathion, Scourge and naled applied against caged adult Culicoides furens and Culex quinquefasciatus in open and vegetated terrain.

    PubMed

    Linley, J R; Jordan, S

    1992-03-01

    The adulticidal effect of ULV and thermal fog malathion, Scourge and naled was tested at 2x label dosage (1.42, 0.22, 0.39 oz/acre, respectively) against caged Culicoides furens and Culex quinquefasciatus in open and vegetated (orange grove) terrain. Cages were at 122 cm elevation and positioned at 15.2, 45.7, 76.2, 106.7, 137.2 and 167.6 m from the line of insecticide release. Ultra-low volume applications of all 3 insecticides were markedly more effective than thermal fog under all conditions, especially in vegetated terrain. Of the 3 insecticides, malathion performed the poorest, especially against Cx. quinquefasciatus (in which there was some resistance) and particularly when applied as thermal fog. Scourge and naled were about equally effective. The best adulticide against C. furens was naled, which was clearly superior applied as ULV. It yielded 75% mortality out to 283 m in the open, and to 38 m in the presence of dense vegetation. PMID:1583493

  7. Toxicity of pirimiphos methyl (Actellic 25EC) on Anopheles gambiae s.s., Culex quinquefasciatus (Diptera: Culicidae), and potential biocontrol agent, Poecilia reticulata (Pisces: Poeciliidae).

    PubMed

    Anogwih, Joy A

    2014-08-01

    The toxicity of an emulsifiable formulation of pirimiphos methyl (Actellic 25EC) on Anopheles gambiae s.s. Giles, Culex quinquefasciatus Say (Diptera: Culicidae), and predator fish Poecilia reticulata Peters (Pisces: Poeciliidae) was investigated. Acute toxicity tests were carried out to determine the effect of the larvicide on mosquito larvae and fish species. To investigate the nontarget effects on P. reticulata, fish of similar size (3.5 +/- 0.2 cm) were randomly selected and exposed for 28 d, under static renewal bioassay, to sublethal concentrations of the larvicide capable of killing 30 and 70% of Cx. quinquefasciatus. The 24 h LC50 value of pirimiphos methyl on the test organisms ranged between 20.44 and 697.30 microg liter(-1). The ultrastructural changes observed in the intestinal cells of P. reticulata were characterized by degenerating cell membranes with gradual loss of gray area in pycnotic nucleus at lower concentration. Marked damage was found at higher concentration including distinct loss of gray areas in cytosol, absence of cristae, numerous ruptures, and several dead cells. Pirimiphos methyl was toxic to a predatory fish species, and for its relevance in vector control and crop protection, warrants cumulative assessment to establish its comprehensive ecological risk, and the dosage required for field larviciding.

  8. Synthesis of silver and gold nanoparticles using Jasminum nervosum leaf extract and its larvicidal activity against filarial and arboviral vector Culex quinquefasciatus Say (Diptera: Culicidae).

    PubMed

    Lallawmawma, H; Sathishkumar, Gnanasekar; Sarathbabu, Subburayan; Ghatak, Souvik; Sivaramakrishnan, Sivaperumal; Gurusubramanian, Guruswami; Kumar, Nachimuthu Senthil

    2015-11-01

    Silver and gold nanoparticles of Jasminum nervosum L. had unique optical properties such as broad absorbance band in the visible region of the electromagnetic spectrum. Characterization of the nanoparticles using UV spectrophotometer, Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy confirmed that the particles were silver (AgNPs) and gold (AuNPs) ranging between 4-22 and 2-20 nm with an average particles size of 9.4 and 10 nm, respectively. AgNPs and AuNPs of J. nervosum had high larvicidal activity on the filarial and arboviral vector, Culex quinquefasciatus, than the leaf aqueous extract. Observed lethal concentrations (LC50 and LC95) against the third instar larvae were 57.40 and 144.36 μg/ml for AgNPs and 82.62 and 254.68 μg/ml for AuNPs after 24 h treatment, respectively. The lethal time to kill 50% of C. quinquefasciatus larvae were 2.24 and 4.51 h at 150 μg/ml of AgNPs and AuNPs, respectively, while in the case of aqueous leaf extract of J. nervosum it was 9.44 h at 500 μg/ml (F 2,14 = 397.51, P < 0.0001). The principal component analysis plot presented differential clustering of the aqueous leaf extract, AgNP and AuNPs in relation to lethal dose and lethal time. It is concluded from the present findings that the biosynthesised AgNPs and AuNPs using leaf aqueous extract of J. nervosum could be an environmentally safer nanobiopesticide, and provided potential larvicidal effect on C. quinquefasciatus larvae which could be used for prevention of several dreadful diseases.

  9. The Influence of Fatty Acid Methyl Esters (FAMEs) in the Biochemistry and the Na(+)/K(+)-ATPase Activity of Culex quinquefasciatus Larvae.

    PubMed

    Silva, Lilian N D; Ribeiro-Neto, José A; Valadares, Jéssica M M; Costa, Mariana M; Lima, Luciana A R S; Grillo, Luciano A M; Cortes, Vanessa F; Santos, Herica L; Alves, Stênio N; Barbosa, Leandro A

    2016-08-01

    Culex quinquefasciatus is the main vector of lymphatic filariasis and combating this insect is of great importance to public health. There are reports of insects that are resistant to the products currently used to control this vector, and therefore, the search for new products has increased. In the present study, we have evaluated the effects of fatty acid methyl esters (FAMEs) that showed larvicidal activity against C. quinquefasciatus, on glucose, total protein, and triacylglycerol contents and Na(+)/K(+)-ATPase activity in mosquito larvae. The exposure of the fourth instar larvae to the compounds caused a decrease in the total protein content and an increase in the activity of the Na(+)/K(+)-ATPase. Furthermore, the direct effect of FAMEs on cell membrane was assessed on purified pig kidney Na(+)/K(+)-ATPase membranes, erythrocyte ghost membranes, and larvae membrane preparation. No modifications on total phospholipids and cholesterol content were found after FAMEs 20 min treatment on larvae membrane preparation, but only 360 µg/mL FAME 2 was able to decrease total phospholipid of erythrocyte ghost membrane. Moreover, only 60 and 360 µg/mL FAME 3 caused an activation of purified Na(+)/K(+)-ATPase, that was an opposite effect of FAMEs treatment in larvae membrane preparation, and caused an inhibition of the pump activity. These data together suggest that maybe FAMEs can modulate the Na(+)/K(+)-ATPase on intact larvae for such mechanisms and not for a direct effect, one time that the direct effect of FAMEs in membrane preparation decreased the activity of Na(+)/K(+)-ATPase. The biochemical changes caused by the compounds were significant and may negatively influence the development and survival of C. quinquefasciatus larvae.

  10. Geomapping generalized eigenvalue frequency distributions for predicting prolific Aedes albopictus and Culex quinquefasciatus habitats based on spatiotemporal field-sampled count data.

    PubMed

    Jacob, Benjamin G; Morris, Joel A; Caamano, Erick X; Griffith, Daniel A; Novak, Robert J

    2011-02-01

    Marked spatiotemporal variabilities in mosquito infection of arboviruses require adaptive strategies for determining optimal field-sampling timeframes, pool screening, and data analyses. In particular, the error distribution and aggregation patterns of adult arboviral mosquitoes can vary significantly by species, which can statistically bias analyses of spatiotemporal-sampled predictor variables generating misinterpretation of prolific habitat surveillance locations. Currently, there is a lack of reliable and consistent measures of risk exposure based on field-sampled georeferenced explanatory covariates which can compromise quantitative predictions generated from arboviral mosquito surveillance models for implementing larval control strategies targeting productive habitats. In this research we used spatial statistics and QuickBird visible and near-infra-red data for determining trapping sites that were related to Culex quinquefasciatus and Aedes albopictus species abundance and distribution in Birmingham, Alabama. Initially, a Land Use Land Cover (LULC) model was constructed from multiple spatiotemporal-sampled georeferenced predictors and the QuickBird data. A Poisson regression model with a non-homogenous, gamma-distributed mean then decomposed the data into positive and negative spatial filter eigenvectors. An autoregressive process in the error term then was used to derive the sample distribution of the Moran's I statistic for determining latent autocorrelation components in the model. Spatial filter algorithms established means, variances, distributional functions, and pairwise correlations for the predictor variables. In doing so, the eigenfunction spatial filter quantified the residual autocorrelation error in the mean response term of the model as a linear combination of various distinct Cx. quinquefasciatus and Ae. albopictus habitat map patterns. The analyses revealed 18-27% redundant information in the data. Prolific habitats of Cx. quinquefasciatus and

  11. Interaction of Lysinibacillus sphaericus Cry48Aa/Cry49Aa toxin with midgut brush-border membrane fractions from Culex quinquefasciatus larvae.

    PubMed

    Guo, Q-Y; Hu, X-M; Cai, Q-X; Yan, J-P; Yuan, Z-M

    2016-04-01

    The Cry48Aa/Cry49Aa mosquitocidal toxin from Lysinibacillus sphaericus was uniquely composed of a three-domain (Cry) toxin and binary (Bin) toxin-like protein, with high toxicity against Culex spp. However, its mode of action against the target mosquitoes is still unknown. In this study, Cry48Aa, Cry49Aa and its N- and C-terminal truncated proteins were expressed and purified, and the binding affinities of the purified proteins with midgut brush-border membrane fractions (BBMFs) from Culex quin-quefasciatus larvae were performed. The results showed that both Cry48Aa and Cry49Aa have specific and high binding affinity to BBMFs, with dissociation constants of 9.5 ± 1.8 and 25.4 ± 3.8 nM, respectively. Competition assays demonstrated that Cry49Aa C-terminal derivatives were able to bind to the BBMFs, whereas Far-Western dot blot analysis revealed that its N-terminal constructs interacted with Cry48Aa. Nevertheless, larvicidal activity was almost lost when Cry49Aa truncated proteins, either individually or in pairs, combined with Cry48Aa. It is concluded that Cry49Aa is responsible for receptor binding and interaction with Cry48Aa and plays an important role in the mechanism of action of these two-component toxins. PMID:26748768

  12. Larvicidal activity of Ipomoea cairica (L.) Sweet and Ageratina adenophora (Spreng.) King & H. Rob. plant extracts against arboviral and filarial vector, Culex quinquefasciatus Say (Diptera: Culicidae).

    PubMed

    Samuel, Lallianrawna; Lalrotluanga; Muthukumaran, Rajendra Bose; Gurusubramanian, Guruswami; Senthilkumar, Nachimuthu

    2014-06-01

    Culex quinquefasciatus Say, an arboviral and filarial vector, is one of the most widespread mosquitoes in the world, and insecticide-resistant populations have been reported worldwide. Due to the emergence of resistance in C. quinquefasciatus plant based products or plant extracts may be alternative sources in integrated vector management program. The present study was carried out to establish the larvicidal activities of crude solvent extracts prepared from flowers and leaves of Ipomoea cairica and Ageratina adenophora against third instar larvae of C. quinquefasciatus as target species. The plant extracts were prepared with petroleum ether, chloroform and methanol solvents using sequential extraction method to determine the best extractant for subsequent isolation and characterization of active ingredient. The total yield of plant extract in the Soxhlet extraction ranged between 0.79% and 19.35%. The qualitative phytochemical study of the plant extracts from different solvents showed the presence of alkaloids, flavonoids, phenols, terpenes, saponins and tannins in different combinations. I. cairica and A. adenophora plant extracts were found to be effective against third instar larvae of C. quinquefasciatus causing 77-100% mortality at 48h. Highest mortality was observed at 500ppm and the order of larvicidal action was observed to be of methanol extract of I. cairica flower>petroleum ether extract of A. adenophora leaf>chloroform extract of I. cairica leaf. High mortality (100%) with low LC50 and LT50 were observed in methanolic flower extract (LC50 - 8.43ppm; LT50 - 2.51h at 48h) of I. cairica, and petroleum ether (LC50 - 133.56ppm; LT50 - 9.45h at 48h) leaf extract of A. adenophora. Lethal concentration (LC50 and LC90) values gradually decreased with the exposure periods, lethal time (LT50 and LT90) decreased with the concentration in bioassay experiment with the crude plant extracts. There was a significant correlation (three-way factorial ANOVA) was noticed

  13. Ultrastructural studies on the sporogony of Hepatozoon spp. in Culex quinquefasciatus say, 1823 fed on infected Caiman crocodilus and Boa constrictor from northern Brazil.

    PubMed

    Paperna, I; Lainson, R

    2003-08-01

    Laboratory reared Culex quinquefasciatus Say, 1823 originating from the vicinity of Belem, in northern Brazil, were allowed to engorge on caimans (Caiman c. crocodilus) infected with Hepatozoon caimani (Carini, 1909) and boas (Boa constrictor) infected with H. cf. terzii (Sambon and Seligmann, 1907) both from Para State. Engorged mosquitoes killed on successive days post-feeding (p.f.) were studied by transmission electron microscopy. Images of oocysts from 13 days p.f., caiman-fed mosquitoes were also examined by scanning electron microscopy. The Hepatozoon spp. from the respective hosts differed in their ability to develop in C. quinquefasciatus. Most female mosquitoes fed on caimans, became fully engorged, and survived beyond 22 days p.f., whereas those engorged on boa became debilitated and did not survive beyond 9 days p.f. In boa-fed mosquitoes oocysts were found on the 6th day p.f. The few mosquitoes surviving to the 9th day p.f. contained either undivided oocysts or those that had already commenced sporogenic division. By 8-10 days p.f. caiman-fed mosquitoes contained uninucleate oocysts. Sporogonic divisions were observed from day 12 p.f. onwards. Although sporogenic development conformed in general with the previously reported accounts, the study allowed a more detailed examination of the plasmalemmal endocytotic system, and the consolidation of the crystalline body in specialized 'factories' of cystalline material. Sporozoite differentiation occasionally started on the 18th day p.f., but otherwise was observed only on day 22 p.f.

  14. Landscape factors influencing the spatial distribution and abundance of mosquito vector Culex quinquefasciatus (Diptera: Culicidae) in a mixed residential-agricultural community in Hawai'i

    USGS Publications Warehouse

    Reiter, M.E.; Lapointe, D.A.

    2007-01-01

    Mosquito-borne avian diseases, principally avian malaria (Plasmodium relictum Grassi and Feletti) and avian pox (Avipoxvirus sp.) have been implicated as the key limiting factor associated with recent declines of endemic avifauna in the Hawaiian Island archipelago. We present data on the relative abundance, infection status, and spatial distribution of the primary mosquito vector Culex quinquefasciatus Say (Diptera: Culicidae) across a mixed, residential-agricultural community adjacent to Hawai'i Volcanoes National Park on Hawai'i Island. We modeled the effect of agriculture and forest fragmentation in determining relative abundance of adult Cx. quinquefasciatus in Volcano Village, and we implement our statistical model in a geographic information system to generate a probability of mosquito capture prediction surface for the study area. Our model was based on biweekly captures of adult mosquitoes from 20 locations within Volcano Village from October 2001 to April 2003. We used mixed effects logistic regression to model the probability of capturing a mosquito, and we developed a set of 17 competing models a priori to specifically evaluate the effect of agriculture and fragmentation (i.e., residential landscapes) at two spatial scales. In total, 2,126 mosquitoes were captured in CO 2-baited traps with an average probability of 0.27 (SE = 0.10) of capturing one or more mosquitoes per trap night. Twelve percent of mosquitoes captured were infected with P. relictum. Our data indicate that agricultural lands and forest fragmentation significantly increase the probability of mosquito capture. The prediction surface identified areas along the Hawai'i Volcanoes National Park boundary that may have high relative abundance of the vector. Our data document the potential of avian malaria transmission in residential-agricultural landscapes and support the need for vector management that extends beyond reserve boundaries and considers a reserve's spatial position in a highly

  15. Development of a controlled release formulation of an indigenous insect growth regulator, DPE-28, a substituted diphenylether, for controlling the breeding of Culex quinquefasciatus

    PubMed Central

    Kalyanasundaram, M.; Mathew, Nisha; Elango, A.; Padmanabhan, V.

    2011-01-01

    Background & objectives: DPE-28, a substituted diphenyl ether (2,6-ditertiarybutyl phenyl-2’,4’-dinitro phenyl ether) was reported to exhibit promising insect growth regulating activity against Culex quinquefasciatus, the vector of lymphatic filariasis. A controlled release formulation (CRF) of DPE-28 has been developed to control Cx. quinquefasciatus in its breeding habitats. Toxicity of DPE-28, safety to non-target mosquito predators and the release profile of the CRF of DPE-28 are studied and discussed. Methods: The acute oral and dermal toxicity was tested in male and female Wistar rats as per the Organization for Economic Cooperation and Development (OECD) guidelines 425 and 402 respectively. The toxicity of DPE-28 to non-target predators was tested as per the reported procedure from this laboratory. The CRF of DPE-28 was prepared by following the reported procedure developed at this laboratory earlier. The concentration of DPE-28 released from the CRF was monitored by HPLC by constructing a calibration graph by plotting the peak area in the Y-axis and the concentration of DPE-28 in the X-axis. Results: DPE-28 has been tested for acute oral toxicity and found to be moderately toxic with LD50 value of 1098 mg/kg body weight (b.w). The results of the acute dermal toxicity and skin irritation studies reveal that DPE-28 is safe and non-irritant. DPE-28 when tested at 0.4 mg/litre against non-target mosquito predators did not produce any mortality. The release profile of the active ingredient DPE-28 from the CRF by HPLC technique showed that the average daily release (ADR) of DPE-28 ranged from 0.07 to 5.0 mg/litre during first four weeks. Thereafter the matrix started eroding and the ADR ranged from 5 to 11 mg/litre during the remaining 5 wk. The cumulative release of active ingredient showed that > 90 per cent of the active ingredient was released from the matrix. Interpretation & conclusions: The controlled release matrix of DPE-28 was thus found to inhibit

  16. Efficacy of several commercially formulated essential oils against caged female Aedes albopictus and Culex quinquefasciatus when operationally applied via an automatic-timed insecticide application system.

    PubMed

    Cilek, J E; Hallmon, C F; Johnson, R

    2011-09-01

    The effectiveness of several commercially available products containing plant essential oils against caged female Aedes albopictus and Culex quinquefasciatus was studied. Products operationally applied via an automatic-timed insecticide application system (MistAway) at maximum label rates were EcoExempt MC (9.0 ml/liter, rosemary oil [18% AI], cinnamon oil [2% AI], lemongrass oil [2% AI], plus 78% "other ingredients" in wintergreen oil). Misting System Concentrate (4 ml/liter, oil of Juniperus virginiana [85% AI]), Mosquito Barrier (31.1 ml/liter, garlic oil [99.3% AI], and citric acid [0.5% AI]), and No-See-Um Organic Repellent (99.5 ml/liter, lemongrass [4% AI], citronella [3% AI], castor oil [3% AI], sodium laurate [3%], and garlic oil [1% AI] in an 86% [AI] mixture of wintergreen oil, lecithin, and water). All products were compared with a commercial formulation of synergized pyrethrins, Riptide (9.0 ml/liter, pyrethrins [5% AI], piperonyl butoxide [25% AI]), as a standard. Mortality was the greatest for Riptide to both mosquito species with effectiveness influenced by distance from the nozzle (ranging from > 80% at 3 m to > 10% at 20 m). The essential oil products resulted in < 10% mortality for each species regardless of application exposure distance with the exception of EcoExempt, which gave approximately 13% mortality of caged female Ae. albopictus 6 m from the nozzles.

  17. Activation, orientation and landing of female Culex quinquefasciatus in response to carbon dioxide and odour from human feet: 3-D flight analysis in a wind tunnel.

    PubMed

    Lacey, E S; Cardé, R T

    2011-03-01

    This study investigated the interaction between carbon dioxide (CO(2) ) and human foot odour on activation, upwind orientation and landing of host-seeking female Culex quinquefasciatus (Say) (Diptera: Culicidae) in a wind tunnel. More mosquitoes landed on warmed glass beads coated with foot odour than on clean beads; adding a plume of 4% CO(2) did not influence the proportion of mosquitoes landing. A second experiment used 3-dimensional video tracking to assess flight performance. Activation was more rapid with CO(2) and with CO(2) + foot odour than with clean air or with foot odour alone. Upwind flights were fastest with CO(2) and with clean air, and slowest with foot odour; the CO(2) + foot odour treatment overlapped the previous three treatments in significance. Flight headings tended more towards due upwind with CO(2) and with clean air than with CO(2) + foot odour or with foot odour alone. In both experiments, many mosquitoes flew upwind in clean air. There was little evidence of females changing course upon entering or exiting the CO(2) plume or reacting to foot odour during flight.

  18. Assessment of long-range correlation in animal behavior time series: The temporal pattern of locomotor activity of Japanese quail (Coturnix coturnix) and mosquito larva (Culex quinquefasciatus)

    NASA Astrophysics Data System (ADS)

    Kembro, Jackelyn M.; Flesia, Ana Georgina; Gleiser, Raquel M.; Perillo, María A.; Marin, Raul H.

    2013-12-01

    Detrended Fluctuation Analysis (DFA) is a method that has been frequently used to determine the presence of long-range correlations in human and animal behaviors. However, according to previous authors using statistical model systems, in order to correctly use DFA different aspects should be taken into account such as: (1) the establishment by hypothesis testing of the absence of short term correlation, (2) an accurate estimation of a straight line in the log-log plot of the fluctuation function, (3) the elimination of artificial crossovers in the fluctuation function, and (4) the length of the time series. Taking into consideration these factors, herein we evaluated the presence of long-range correlation in the temporal pattern of locomotor activity of Japanese quail (Coturnix coturnix) and mosquito larva (Culex quinquefasciatus). In our study, modeling the data with the general autoregressive integrated moving average (ARFIMA) model, we rejected the hypothesis of short-range correlations (d=0) in all cases. We also observed that DFA was able to distinguish between the artificial crossover observed in the temporal pattern of locomotion of Japanese quail and the crossovers in the correlation behavior observed in mosquito larvae locomotion. Although the test duration can slightly influence the parameter estimation, no qualitative differences were observed between different test durations.

  19. Lack of Cross-Resistance to Cry19A from Bacillus thuringiensis subsp. jegathesan in Culex quinquefasciatus (Diptera: Culicidae) Resistant to Cry Toxins from Bacillus thuringiensis subsp. israelensis

    PubMed Central

    Wirth, Margaret C.; Delécluse, Armelle; Walton, William E.

    2001-01-01

    Culex quinquefasciatus mosquitoes with high levels of resistance to single or multiple toxins from Bacillus thuringiensis subsp. israelensis were tested for cross-resistance to the Bacillus thuringiensis subsp. jegathesan polypeptide Cry19A. No cross-resistance was detected in mosquitoes that had been selected with the Cry11A, Cry4A and Cry4B, or Cry4A, Cry4B, Cry11A, and CytA toxins. A low but statistically significant level of cross-resistance, three to fourfold, was detected in the colony selected with Cry4A, Cry4B, and Cry11A. This cross-resistance was similar to that previously detected with B. thuringiensis subsp. jegathesan in the same colony. These data help explain the toxicity of B. thuringiensis subsp. jegathesan against the resistant colonies and indicate that the Cry19A polypeptide might be useful in managing resistance and/or as a component of synthetic combinations of mosquitocidal toxins. PMID:11282656

  20. Effects of the essential oils of Lippia turbinata and Lippia polystachya (Verbenaceae) on the temporal pattern of locomotion of the mosquito Culex quinquefasciatus (Diptera: Culicidae) larvae.

    PubMed

    Kembro, Jackelyn M; Marin, Raúl H; Zygadlo, Julio A; Gleiser, Raquel M

    2009-04-01

    The essential oils (EO) of Lippia turbinata (TUR) and Lippia polystachya (POL) have shown lethal effects against mosquito larvae. The present work evaluated whether these EO at doses ranging from sublethal to lethal (20, 40 and 80 ppm) modify the temporal pattern of locomotion of Culex quinquefasciatus larvae. Larvae were individually placed in glass boxes, and their activity recorded at 0.3 s intervals during 40 min. Individuals treated with doses >40 ppm of either EO significantly decreased their ambulation speed and the percentage of total time ambulating compared to controls. TUR 80 ppm decreased their ambulation even sooner than POL 80 ppm, when compared to their respective controls. These findings are consistent with the neurotoxic effect against insects attributed to alpha-Thujone, a main component of both EO. A detrended fluctuation fractal analysis evaluating the complexity and organisation of the temporal pattern of locomotion showed fractal patterns in all animals. Both sublethal and lethal doses of TUR and POL increased the complexity of ambulation. Interestingly, for POL 20 ppm, an increase in complexity was observed, while no changes in general activity were detected, suggesting that fractal analysis may be more sensitive to detect behavioural changes than general activity evaluation. PMID:19085007

  1. A single nucleotide change in a core promoter is involved in the progressive overexpression of the duplicated CYP9M10 haplotype lineage in Culex quinquefasciatus.

    PubMed

    Itokawa, Kentaro; Komagata, Osamu; Kasai, Shinji; Tomita, Takashi

    2015-11-01

    Although the importance of cis-acting mutations on detoxification enzyme genes for insecticide resistance is widely accepted, only a few of them have been determined as concrete mutations present in genomic DNA till date. The overexpression of a cytochrome P450 gene, CYP9M10, is associated with pyrethroid resistance in the southern house mosquito Culex quinquefasciatus. The haplotypes of CYP9M10 exhibiting overexpression (resistant haplotypes) belong to one specific phylogenetic lineage that shares high nucleotide sequence homology and the same insertion of a transposable element. Among the resistant haplotypes, allelic progression involving an additional cis-acting mutation and gene duplication evolved a CYP9M10 haplotype associated with extremely high transcription and strong pyrethroid resistance. Here we show that a single nucleotide substitution G-27A, which is located near the transcription start site of CYP9M10, is involved in the progression of the duplicated haplotype lineage. The deletion of a 7-bp AT-rich sequence that includes nucleotide -27 inhibited the initiation of transcription from the original transcriptional initiation site. The mutation was suspected to reside within a core promoter, TATA-box, of CYP9M10. PMID:26494013

  2. Insecticide resistance status, esterase activity, and electromorphs from mosquito populations of Culex quinquefasciatus Say (Diptera: Culicidae), in Houston (Harris County), Texas.

    PubMed

    Pietrantonio, P V; Gibson, G; Nawrocki, S; Carrier, F; Knight, W P

    2000-06-01

    Culex quinquefasciatus Say is a vector of St. Louis encephalitis (SLE) in Texas. This disease is endemic and prevalent in the Houston area. Disease prevention through mosquito control is mainly targeted against adults by application of a resmethrin-piperonyl butoxide formulation (Scourge). Immature mosquitoes were collected from eight areas in Harris County during 1998. The susceptibility status of these populations to Scourge, malathion, and resmethrin, the latter alone or with an esterase inhibitor as a synergist, was determined using a bottle assay with females. The population structure was investigated by electrophoretic analysis of esterases and their activity. Individual females were also analyzed for esterase activity by plate assay and for isoenzyme pattern by native PAGE. Bioassays indicated high levels of resistance to malathion in all areas. In addition, the effectiveness of Scourge in mosquitoes from area 51 deteriorated throughout the season. A localized, distinctive esterase pattern and activity level was observed in mosquitoes from different areas. Overall, the frequency of esterases Est alpha 2 (A2)/Est beta 2 (B2) was higher than that of Est beta 1 (B1). Altogether, these results indicate the onset of a fragile situation for mosquito control that should be further analyzed to effectively maintain the SLE prevention program for Harris County.

  3. Resistance in a laboratory population of Culex quinquefasciatus (Diptera: Culicidae) to Bacillus sphaericus binary toxin is due to a change in the receptor on midgut brush-border membranes.

    PubMed

    Nielsen-Leroux, C; Charles, J F; Thiéry, I; Georghiou, G P

    1995-02-15

    Direct binding experiments with isolated brush border membrane fractions (BBMF) from larvae of a susceptible laboratory strain of Culex quinquefasciatus Say, indicated the presence of a single class of Bacillus sphaericus binary toxin receptors. The dissociation constant (Kd) was approximately 11 nM and the maximum binding capacity (Bmax) approximately 8 pmol/mg BBMF protein. Similar binding experiments with a field population of C. quinquefasciatus that had been selected in the laboratory to more than 100,000-fold resistance to B. sphaericus binary toxin failed to reveal the presence of any specific binding. Thus this resistant strain had lost the functional receptor for B. sphaericus toxin. The binding characteristics of BBMF from the F1 larval progeny (susceptible females x resistant males) were very close to those of the parental susceptible strain, consistent with the resistance being recessive. PMID:7883005

  4. Nectar protein content and attractiveness to Aedes aegypti and Culex pipiens in plants with nectar/insect associations.

    PubMed

    Chen, Zhongyuan; Kearney, Christopher M

    2015-06-01

    We chose five easily propagated garden plants previously shown to be attractive to mosquitoes, ants or other insects and tested them for attractiveness to Culex pipiens and Aedes aegypti. Long term imbibition was tested by survival on each plant species. Both mosquito species survived best on Impatiens walleriana, the common garden impatiens, followed by Asclepias curassavica, Campsis radicans and Passiflora edulis, which sponsored survival as well as the 10% sucrose control. Immediate preference for imbibition was tested with nectar dyed in situ on each plant. In addition, competition studies were performed with one dyed plant species in the presence of five undyed plant species to simulate a garden setting. In both preference studies I. walleriana proved superior. Nectar from all plants was then screened for nectar protein content by SDS-PAGE, with great variability being found between species, but with I. walleriana producing the highest levels. The data suggest that I. walleriana may have value as a model plant for subsequent studies exploring nectar delivery of transgenic mosquitocidal proteins. PMID:25792420

  5. CytA enables CryIV endotoxins of Bacillus thuringiensis to overcome high levels of CryIV resistance in the mosquito, Culex quinquefasciatus.

    PubMed

    Wirth, M C; Georghiou, G P; Federici, B A

    1997-09-30

    Cry proteins produced by Bacillus thuringiensis are selective biodegradable insecticides used increasingly in bacterial insecticides and transgenic plants as alternatives to synthetic chemical insecticides. However, the potential for development of resistance and cross-resistance in target insect populations to Cry proteins used alone or in combination threatens the more widespread use of this novel pest control technology. Here we show that high levels of resistance to CryIV proteins in larvae of the mosquito, Culex quinquefasciatus, can be suppressed or reduced markedly by combining these proteins with sublethal quantities of CytA, a cytolytic endotoxin of B. thuringiensis. Resistance at the LC95 level of 127-fold for a combination of three CryIV toxins (CryIVA, B, and D), resulting from 60 generations of continuous selection, was completely suppressed by combining sporulated powders of CytA in a 1:3 ratio with sporulated powders of a CryIVA, CryIVB, and CryIVD strain. Combining the CytA strain with a CryIVA and CryIVB strain also completely suppressed mosquito resistance of 217-fold to the latter toxins at the LC95 level, whereas combination of CytA with CryIVD reduced resistance in a CryIVD-selected mosquito strain from greater than 1,000-fold to less than 8-fold. The CytA/CryIV model provides a potential molecular genetic strategy for engineering resistance management for Cry proteins directly into bacterial insecticides and transgenic plants.

  6. Influence of Exposure to Single versus Multiple Toxins of Bacillus thuringiensis subsp. israelensis on Development of Resistance in the Mosquito Culex quinquefasciatus (Diptera: Culicidae)

    PubMed Central

    Georghiou, G. P.; Wirth, M. C.

    1997-01-01

    The impending widespread use of transgenic crop plants encoding a single insecticidal toxin protein of Bacillus thuringiensis has focused attention on the perceived risk of rapid selection of resistance in target insects. We have used Bacillus thuringiensis subsp. israelensis toxins as a model system and determined the speed and magnitude of evolution of resistance in colonies of the mosquito Culex quinquefasciatus during selection for 28 consecutive generations with single or multiple toxins. The parental strain was synthesized by combining approximately 500 larvae from each of 19 field collections obtained from the states of California, Oregon, Louisiana, and Tennessee. At least 10,000 larvae were selected in each generation of each line at an average mortality level of 84%. The susceptibilities of the parental and selected lines were compared in parallel tests in every third generation by using fresh suspensions of toxin powders. The normal toxin complement of B. thuringiensis subsp. israelensis consists of four toxins, CryIVA, CryIVB, CryIVD, and CytA. Resistance became evident first in the line that was selected with a single toxin (CryIVD), attaining the highest level (resistance ratio [RR], >913 at 95% lethal concentration) by generation F(inf28) when the study was completed. Resistance evolved more slowly and to a lower level (RR, >122 by F(inf25)) in the line selected with two toxins (CryIVA+CryIVB) and lower still (RR, 91 by F(inf28)) in the line selected with three toxins (CryIVA+CryIVB+ CryIVD). Resistance was remarkably low (RR, 3.2) in the line selected with all four toxins. The results reveal the importance of the full complement of toxins found in natural populations of B. thuringiensis subsp. israelensis as an effective approach to resistance management. PMID:16535542

  7. Hepatozoon cf. terzii (Sambon & Seligman, 1907) infection in the snake boa constrictor constrictor from north Brazil: transmission to the mosquito Culex quinquefasciatus and the lizard Tropidurus torquatus.

    PubMed

    Paperna, I; Lainson, R

    2004-06-01

    Specimens of Hepatozoon-infected Boa constrictor constrictor were obtained from localities in Pará State, north Brazil. Gametocytes in erythrocytes of the peripheral blood measured 10 x 2.5-16.2 x 3.7 microns. They were similar to those described as Haemogregarina terzii by Sambon & Seligmann (1907) in B. c. constrictor, in that they did not distort the infected erythrocyte, and their dimensions approximated those given by Carini (1947). Lungs and liver of infected snakes contained actively dividing meronts of a single type, and cysts containing two to six cystozoites were also present in the liver. Our initial feeding of Culex quinquefasciatus on infected snakes consistently resulted in a heavy death-rate of the engorged mosquitoes, with only a few surviving till the 9th day post feeding. These contained numerous oocysts which were undivided or in early stages of division. A fifth and final experiment, however, provided a few mosquitoes surviving up to 21 days post infection (dpi), and these contained fully sporulated oocysts measuring 190-200 microns in diameter and containing over 60 sporocysts of 19-30 microns in diameter. The number of sporozoites in each sporocyst was estimated as approximately 50. The nature of the parasite's sporogonic cycle in the mosquito thus justifies inclusion of this haemogregarine in the genus Hepatozoon. Two wild-caught specimens of the lizard Tropidurus torquatus were fed with mosquitoes containing fully developed oocysts (21 dpi). When sacrificed, three months later, large numbers of dizoic, tetrazoic and hexazoic cysts were demonstrated in their livers. Cystozoites released from these cysts were shown to possess a conspicuous refractile body.

  8. Biosynthesis, mosquitocidal and antibacterial properties of Toddalia asiatica-synthesized silver nanoparticles: do they impact predation of guppy Poecilia reticulata against the filariasis mosquito Culex quinquefasciatus?

    PubMed

    Murugan, Kadarkarai; Venus, Joseph Selvaraj Eugine; Panneerselvam, Chellasamy; Bedini, Stefano; Conti, Barbara; Nicoletti, Marcello; Sarkar, Santosh Kumar; Hwang, Jiang-Shiou; Subramaniam, Jayapal; Madhiyazhagan, Pari; Kumar, Palanisamy Mahesh; Dinesh, Devakumar; Suresh, Udaiyan; Benelli, Giovanni

    2015-11-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. Furthermore, pathogens and parasites polluting water also constitute a severe plague for populations of developing countries. In this study, silver nanoparticles (AgN) were biosynthesized a cheap aqueous extract of T. asiatica leaves as reducing and stabilizing agent. The formation of nanoparticle was confirmed by surface Plasmon resonance band illustrated in UV-vis spectrophotometer. AgN were characterized by FTIR, SEM, EDX, and XRD analyses. AgN were mostly spherical in shape, crystalline in nature, with face-centered cubic geometry, and their mean size was 25-30 nm. T. asiatica aqueous extract and green-synthesized AgN showed excellent larvicidal and pupicidal toxicity against the filariasis vector Culex quinqufasciatus, both in laboratory and field experiments. AgN LC50 ranged from 16.48 (I instar larvae) to 31.83 ppm (pupae). T. asiatica-synthesized were also highly effective in inhibiting growth of Bacillus subtilis, Klebsiella pneumoniae, and Salmonella typhi using the agar disk diffusion and minimum inhibitory concentration protocol. Lastly, we evaluated if sublethal doses of nanoparticles affect predation rates of fishes, Poecilia reticulata, against C. quinquefasciatus. In AgN-contaminated environment, predation of guppies against mosquito larvae was slightly higher over normal laboratory conditions. Overall, this study highlighted that T. asiatica-synthesized AgN are easy to produce, stable over time, and may be employed at low dosages to reduce populations of filariasis vectors, without detrimental effects on predation rates of mosquito natural enemies.

  9. Biosynthesis, mosquitocidal and antibacterial properties of Toddalia asiatica-synthesized silver nanoparticles: do they impact predation of guppy Poecilia reticulata against the filariasis mosquito Culex quinquefasciatus?

    PubMed

    Murugan, Kadarkarai; Venus, Joseph Selvaraj Eugine; Panneerselvam, Chellasamy; Bedini, Stefano; Conti, Barbara; Nicoletti, Marcello; Sarkar, Santosh Kumar; Hwang, Jiang-Shiou; Subramaniam, Jayapal; Madhiyazhagan, Pari; Kumar, Palanisamy Mahesh; Dinesh, Devakumar; Suresh, Udaiyan; Benelli, Giovanni

    2015-11-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. Furthermore, pathogens and parasites polluting water also constitute a severe plague for populations of developing countries. In this study, silver nanoparticles (AgN) were biosynthesized a cheap aqueous extract of T. asiatica leaves as reducing and stabilizing agent. The formation of nanoparticle was confirmed by surface Plasmon resonance band illustrated in UV-vis spectrophotometer. AgN were characterized by FTIR, SEM, EDX, and XRD analyses. AgN were mostly spherical in shape, crystalline in nature, with face-centered cubic geometry, and their mean size was 25-30 nm. T. asiatica aqueous extract and green-synthesized AgN showed excellent larvicidal and pupicidal toxicity against the filariasis vector Culex quinqufasciatus, both in laboratory and field experiments. AgN LC50 ranged from 16.48 (I instar larvae) to 31.83 ppm (pupae). T. asiatica-synthesized were also highly effective in inhibiting growth of Bacillus subtilis, Klebsiella pneumoniae, and Salmonella typhi using the agar disk diffusion and minimum inhibitory concentration protocol. Lastly, we evaluated if sublethal doses of nanoparticles affect predation rates of fishes, Poecilia reticulata, against C. quinquefasciatus. In AgN-contaminated environment, predation of guppies against mosquito larvae was slightly higher over normal laboratory conditions. Overall, this study highlighted that T. asiatica-synthesized AgN are easy to produce, stable over time, and may be employed at low dosages to reduce populations of filariasis vectors, without detrimental effects on predation rates of mosquito natural enemies. PMID:26122577

  10. A G-protein-coupled receptor regulation pathway in cytochrome P450-mediated permethrin-resistance in mosquitoes, Culex quinquefasciatus

    PubMed Central

    Li, Ting; Cao, Chuanwang; Yang, Ting; Zhang, Lee; He, Lin; Xi, Zhiyong; Bian, Guowu; Liu, Nannan

    2015-01-01

    Rhodopsin-like G protein-coupled receptors (GPCRs) are known to be involved in the GPCR signal transduction system and regulate many essential physiological processes in organisms. This study, for the first time, revealed that knockdown of the rhodopsin-like GPCR gene in resistant mosquitoes resulted in a reduction of mosquitoes’ resistance to permethrin, simultaneously reducing the expression of two cAMP-dependent protein kinase A genes (PKAs) and four resistance related cytochrome P450 genes. The function of rhodopsin-like GPCR was further confirmed using transgenic lines of Drosophila melanogaster, in which the tolerance to permethrin and the expression of Drosophila resistance P450 genes were both increased. The roles of GPCR signaling pathway second messenger cyclic adenosine monophosphate (cAMP) and downstream effectors PKAs in resistance were investigated using cAMP production inhibitor Bupivacaine HCl and the RNAi technique. Inhibition of cAMP production led to significant decreases in both the expression of four resistance P450 genes and two PKA genes and mosquito resistance to permethrin. Knockdown of the PKA genes had shown the similar effects on permethrin resistance and P450 gene expression. Taken together, our studies revealed, for the first time, the role of the GPCR/cAMP/PKA-mediated regulatory pathway governing P450 gene expression and P450-mediated resistance in Culex mosquitoes. PMID:26656663

  11. Ecology of Potential West Nile Virus Vectors in Southeastern Louisiana: Enzootic Transmission in the Relative Absence of Culex quinquefasciatus

    PubMed Central

    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. PMID:23478575

  12. Ecology of potential West Nile virus vectors in southeastern Louisiana: enzootic transmission in the relative absence of Culex quinquefasciatus

    USGS Publications Warehouse

    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.

  13. Experimental infection of Hawai'i 'Amakihi (hemignathus virens) with West Nile virus and competence of a co-occurring vector, culex quinquefasciatus: potential impacts on endemic Hawaiian avifauna.

    USGS Publications Warehouse

    Lapointe, D.A.; Hofmeister, E.K.; Atkinson, C.T.; Porter, R.E.; Dusek, R.J.

    2009-01-01

    Introduced mosquito-borne avian disease is a major limiting factor in the recovery and restoration of native Hawaiian forest birds. Annual epizootics of avian pox (Avipoxvirus) and avian malaria (Plasmodium relictum) likely led to the extinction of some species and continue to impact populations of susceptible Hawaiian honeycreepers (Drepanidinae). The introduction of a novel pathogen, such as West Nile virus (WNV), could result in further population declines and extinctions. During September and October 2004, we infected Hawai'i' Amakihi (Hemignathus virens) with a North American isolate of WNV by needle inoculation and mosquito bite to observe susceptibility, mortality, and illness in this endemic passerine, and to determine the vector competence of the co-occurring, introduced mosquito Culex quinquefasciatus. All experimentally infected Hawai'i ;Amakihi became viremic, with a mean titer >10(5) plaque-forming units (PFU)/ml, and they experienced clinical signs ranging from anorexia and lethargy to ataxia. The fatality rate among needle-inoculated Hawai'i' Amakihi (n=16) was 31.3%, but mortality in free-ranging birds is likely to increase due to predation, starvation, thermal stress, and concomitant infections of avian malaria and pox. Surviving Hawai'i' Amakihi seem to clear WNV from the peripheral blood by 7-10 days postinfection (DPI), and neutralizing antibodies were detected from 9 to 46 DPI. In transmission trials, Hawaiian Cx. quinquefasciatus proved to be a competent vector and Hawai'i Amakihi an adequate amplification host of WNV, suggesting that epizootic WNV could readily become an additional limiting factor of some native Hawaiian bird populations.

  14. First detection of natural infection of Aedes aegypti with Zika virus in Brazil and throughout South America

    PubMed Central

    Ferreira-de-Brito, Anielly; Ribeiro, Ieda P; de Miranda, Rafaella Moraes; Fernandes, Rosilainy Surubi; Campos, Stéphanie Silva; da Silva, Keli Antunes Barbosa; de Castro, Marcia Gonçalves; Bonaldo, Myrna C; Brasil, Patrícia; Lourenço-de-Oliveira, Ricardo

    2016-01-01

    Zika virus (ZIKV) has caused a major epidemic in Brazil and several other American countries. ZIKV is an arbovirus whose natural vectors during epidemics have been poorly determined. In this study, 1,683 mosquitoes collected in the vicinity of ZIKV suspected cases in Rio de Janeiro, Brazil, from June 2015 to May 2016 were screened for natural infection by using molecular methods. Three pools of Aedes aegypti were found with the ZIKV genome, one of which had only one male. This finding supports the occurrence of vertical and/or venereal transmission of ZIKV in Ae. aegypti in nature. None of the examined Ae. albopictus and Culex quinquefasciatus was positive. This is the first report of natural infection by ZIKV in mosquitoes in Brazil and other South American countries. So far, Ae. aegypti is the only confirmed vector of ZIKV during the ongoing Pan-American epidemics. PMID:27706382

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

    PubMed

    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.

  16. Evolution of Resistance in Culex quinquefasciatus (Say) Selected With a Recombinant Bacillus thuringiensis Strain-Producing Cyt1Aa and Cry11Ba, and the Binary Toxin, Bin, From Lysinibacillus sphaericus

    PubMed Central

    Wirth, Margaret C.; Walton, William E.; Federici, Brian A.

    2015-01-01

    Fourth instars of Culex quinquefasciatus (Say) (Diptera: Culicidae) were selected with a recombinant bacterial strain synthesizing the mosquitocidal proteins from Lysinibacillus sphaericus (Bin) and Cry11Ba and Cyt1Aa from Bacillus thuringiensis. Selection was initiated in Generation 1 with a concentration of 0.04 μg/ml, which rose to a maximum selection concentration of 8.0 μg/ml in Generation 14, followed by an unexpected, rapid increase in mortality in Generation 15. Subsequently, a selection concentration of 0.8 μg/ml was determined to be survivable. During this same period, resistance rose to nearly 1,000-fold (by Generation 12) and declined to 18.8-fold in Generation 19. Resistance remained low and fluctuated between 5.3 and 7.3 up to Generation 66. The cross-resistance patterns and interactions among the component proteins were analyzed to identify possible causes of this unusual pattern of evolution. Poor activity in the mid-range concentrations and lower-than-expected synergistic interactions were identified as potential sources of the early resistance. These findings should be considered in the development of genetically engineered strains intended to control nuisance and vector mosquitoes. PMID:26336254

  17. Strong larvicidal activity of three species of Spilanthes (Akarkara) against malaria (Anopheles stephensi Liston, Anopheles culicifacies, species C) and filaria vector (Culex quinquefasciatus Say).

    PubMed

    Pandey, Vibha; Agrawal, Veena; Raghavendra, K; Dash, A P

    2007-12-01

    A system for biocontrol of malaria and filarial mosquito vectors has been developed using herbal extracts of three Spilanthes species, S. acmella L.var oleraceae Clarke, S. calva L. and S. paniculata Wall ex DC. Cent percent mortalities was achieved against the late third/early fourth instar larvae of A. stephensi Liston, A. culicifacies species C and C. quinquefasciatus Say using crude hexane extract obtained from flower heads of Spilanthes spp. Of the three plant species, S. acmella extract proved to be the most effective in inducing complete lethality at minimum doses, the respective LC50 and LC90 values being 4.57 and 7.83 (A. stephensi), 0.87 and 1.92 (A. culicifacies) and 3.11 and 8.89 ppm (C. quinquefasciatus). This was followed by S. calva and S. paniculata extracts, respectively. This is the first report of achieving cent percent lethality against these mosquito larvae using minimal doses of plant extracts from this or any other plant species. PMID:17922235

  18. Studies on the impact of biosynthesized silver nanoparticles (AgNPs) in relation to malaria and filariasis vector control against Anopheles stephensi Liston and Culex quinquefasciatus Say (Diptera: Culicidae).

    PubMed

    Subarani, Selladurai; Sabhanayakam, Selvi; Kamaraj, Chinnaperumal

    2013-02-01

    Biosynthesized nanoparticles have been achieved using environmentally acceptable plant extract and eco-friendly reducing and capping agents. The present study was based on assessments of the larvicidal activities to determine the efficacies of synthesized silver nanoparticles (AgNPs) using aqueous leaf extract of Vinca rosea (L.) (Apocynaceae) against the larvae of malaria vector Anopheles stephensi Liston and filariasis vector Culex quinquefasciatus Say (Diptera: Culicidae). Larvae were exposed to varying concentrations of aqueous extract of V. rosea and synthesized AgNPs for 24, 48, and 72 h. AgNPs were rapidly synthesized using the leaf extract of V. rosea, and the formation of nanoparticles was observed within 15 min. The results recorded from UV-Vis spectrum, Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) support the biosynthesis and characterization of AgNPs. The formation of the AgNPs synthesized from the XRD spectrum compared with the Bragg reflections at 2θ = 29.36, 38.26, 44.51, 63.54, and 77.13° which can be indexed to the (121), (111), (200), (220), and (311) orientations, respectively, confirmed the presence of AgNPs. The FTIR spectra of AgNPs exhibited prominent peaks at the spectra showed sharp and strong absorption band at 3,406.71 to 3,431.90 cm(-1) double in case of NH(2) group of a primary amine (N-H stretch). The presence of the sharp peak at 2,926.54 to 2,925.80 cm(-1) very broad often looks like distorted baseline (O-H carboxylic acids). The band 1,633.26 to 1,625.81 cm(-1) was assigned to C = C alkenes, aromatic ring stretching vibration, respectively. SEM analysis of the synthesized AgNPs clearly showed the clustered and irregular shapes, mostly aggregated and having the size of 120 nm. TEM reveals spherical shape of synthesized AgNPs. Particle size analysis revealed that the size of particles ranges from 25 to 47 nm with average size of 34.61 nm

  19. Variable cross-resistance to Cry11B from Bacillus thuringiensis subsp. jegathesan in Culex quinquefasciatus (Diptera: Culicidae) resistant to single or multiple toxins of Bacillus thuringiensis subsp. israelensis.

    PubMed

    Wirth, M C; Delécluse, A; Federici, B A; Walton, W E

    1998-11-01

    A novel mosquitocidal bacterium, Bacillus thuringiensis subsp. jegathesan, and one of its toxins, Cry11B, in a recombinant B. thuringiensis strain were evaluated for cross-resistance with strains of the mosquito Culex quinquefasciatus that are resistant to single and multiple toxins of Bacillus thuringiensis subsp. israelensis. The levels of cross-resistance (resistance ratios [RR]) at concentrations which caused 95% mortality (LC95) between B. thuringiensis subsp. jegathesan and the different B. thuringiensis subsp. israelensis-resistant mosquito strains were low, ranging from 2.3 to 5.1. However, the levels of cross-resistance to Cry11B were much higher and were directly related to the complexity of the B. thuringiensis subsp. israelensis Cry toxin mixtures used to select the resistant mosquito strains. The LC95 RR obtained with the mosquito strains were as follows: 53.1 against Cq4D, which was resistant to Cry11A; 80.7 against Cq4AB, which was resistant to Cry4A plus Cry4B; and 347 against Cq4ABD, which was resistant to Cry4A plus Cry4B plus Cry11A. Combining Cyt1A with Cry11B at a 1:3 ratio had little effect on suppressing Cry11A resistance in Cq4D but resulted in synergism factors of 4.8 and 11.2 against strains Cq4AB and Cq4ABD, respectively; this procedure eliminated cross-resistance in the former mosquito strain and reduced it markedly in the latter strain. The high levels of activity of B. thuringiensis subsp. jegathesan and B. thuringiensis subsp. israelensis, both of which contain a complex mixture of Cry and Cyt proteins, against Cry4- and Cry11-resistant mosquitoes suggest that novel bacterial strains with multiple Cry and Cyt proteins may be useful in managing resistance to bacterial insecticides in mosquito populations.

  20. Variable Cross-Resistance to Cry11B from Bacillus thuringiensis subsp. jegathesan in Culex quinquefasciatus (Diptera: Culicidae) Resistant to Single or Multiple Toxins of Bacillus thuringienisis subsp. israelensis

    PubMed Central

    Wirth, Margaret C.; Delécluse, Armelle; Federici, Brian A.; Walton, William E.

    1998-01-01

    A novel mosquitocidal bacterium, Bacillus thuringiensis subsp. jegathesan, and one of its toxins, Cry11B, in a recombinant B. thuringiensis strain were evaluated for cross-resistance with strains of the mosquito Culex quinquefasciatus that are resistant to single and multiple toxins of Bacillus thuringiensis subsp. israelensis. The levels of cross-resistance (resistance ratios [RR]) at concentrations which caused 95% mortality (LC95) between B. thuringiensis subsp. jegathesan and the different B. thuringiensis subsp. israelensis-resistant mosquito strains were low, ranging from 2.3 to 5.1. However, the levels of cross-resistance to Cry11B were much higher and were directly related to the complexity of the B. thuringiensis subsp. israelensis Cry toxin mixtures used to select the resistant mosquito strains. The LC95 RR obtained with the mosquito strains were as follows: 53.1 against Cq4D, which was resistant to Cry11A; 80.7 against Cq4AB, which was resistant to Cry4A plus Cry4B; and 347 against Cq4ABD, which was resistant to Cry4A plus Cry4B plus Cry11A. Combining Cyt1A with Cry11B at a 1:3 ratio had little effect on suppressing Cry11A resistance in Cq4D but resulted in synergism factors of 4.8 and 11.2 against strains Cq4AB and Cq4ABD, respectively; this procedure eliminated cross-resistance in the former mosquito strain and reduced it markedly in the latter strain. The high levels of activity of B. thuringiensis subsp. jegathesan and B. thuringiensis subsp. israelensis, both of which contain a complex mixture of Cry and Cyt proteins, against Cry4- and Cry11-resistant mosquitoes suggest that novel bacterial strains with multiple Cry and Cyt proteins may be useful in managing resistance to bacterial insecticides in mosquito populations. PMID:9797262

  1. Mosquito Infestation and Dengue Virus Infection in Aedes aegypti Females in Schools in Mérida, México

    PubMed Central

    García-Rejón, Julián E.; Loroño-Pino, María Alba; Farfán-Ale, José Arturo; Flores-Flores, Luis F.; López-Uribe, Mildred P.; del Rosario Najera-Vazquez, Maria; Nuñez-Ayala, Guadalupe; Beaty, Barry J.; Eisen, Lars

    2011-01-01

    We determined abundance of Aedes aegypti mosquitoes and presence of dengue virus (DENV) in females collected from schools in Mérida, México, during 2008 and 2009. Backpack aspiration from 24 schools produced 468 females of Ae. aegypti and 1,676 females of another human biter, Culex quinquefasciatus. Ae. aegypti females were collected most commonly from classrooms followed by offices and bathrooms. Of these females, 24.7% were freshly fed. Examination of 118 pools of Ae. aegypti females (total of 415 females) for presence of DENV RNA produced 19 positive pools (16.1%). DENV-infected pools were detected from 11 (45.8%) of 24 schools and came from different room types, including classrooms, offices, and bathrooms. The overall rate of DENV infection per 100 Ae. aegypti females was 4.8. We conclude that schools in Mérida present a risk environment for students, teachers, and other personnel to be exposed to mosquitoes and bites of DENV-infected Ae. aegypti females. PMID:21363990

  2. Laboratory and Simulated Field Bioassays to Evaluate Larvicidal Activity of Pinus densiflora Hydrodistillate, Its Constituents and Structurally Related Compounds against Aedes albopictus, Aedes aegypti and Culex pipiens pallens in Relation to Their Inhibitory Effects on Acetylcholinesterase Activity.

    PubMed

    Lee, Dong Chan; Ahn, Young-Joon

    2013-01-01

    The toxicity of Pinus densiflora (red pine) hydrodistillate, its 19 constituents and 28 structurally related compounds against early third-instar larvae of Aedes albopictus (Ae. albopictus), Aedes aegypti (Ae. aegypti) and Culex pipiens palles (Cx. p. pallens) was examined using direct-contact bioassays. The efficacy of active compounds was further evaluated in semi-field bioassays using field-collected larval Cx. p. pallens. Results were compared with those of two synthetic larvicides, temephos and fenthion. In laboratory bioassays, Pinus densiflora hydrodistillate was found to have 24 h LC50 values of 20.33, 21.01 and 22.36 mg/L against larval Ae. albopictus, Ae. aegypti and Cx. p. pallens respectively. Among the identified compounds, thymol, δ-3-carene and (+)-limonene exhibited the highest toxicity against all three mosquito species. These active compounds were found to be nearly equally effective in field trials as well. In vitro bioassays were conducted to examine the acetylcholinesterase (AChE) inhibitory activity of 10 selected compounds. Results showed that there is a noticeable correlation between larvicidal activity and AChE inhibitory activity. In light of global efforts to find alternatives for currently used insecticides against disease vector mosquitoes, Pinus densiflora hydrodistillate and its constituents merit further research as potential mosquito larvicides.

  3. Laboratory and Simulated Field Bioassays to Evaluate Larvicidal Activity of Pinus densiflora Hydrodistillate, Its Constituents and Structurally Related Compounds against Aedes albopictus, Aedes aegypti and Culex pipiens pallens in Relation to Their Inhibitory Effects on Acetylcholinesterase Activity

    PubMed Central

    Lee, Dong Chan; Ahn, Young-Joon

    2013-01-01

    The toxicity of Pinus densiflora (red pine) hydrodistillate, its 19 constituents and 28 structurally related compounds against early third-instar larvae of Aedes albopictus (Ae. albopictus), Aedes aegypti (Ae. aegypti) and Culex pipiens palles (Cx. p. pallens) was examined using direct-contact bioassays. The efficacy of active compounds was further evaluated in semi-field bioassays using field-collected larval Cx. p. pallens. Results were compared with those of two synthetic larvicides, temephos and fenthion. In laboratory bioassays, Pinus densiflora hydrodistillate was found to have 24 h LC50 values of 20.33, 21.01 and 22.36 mg/L against larval Ae. albopictus, Ae. aegypti and Cx. p. pallens respectively. Among the identified compounds, thymol, δ-3-carene and (+)-limonene exhibited the highest toxicity against all three mosquito species. These active compounds were found to be nearly equally effective in field trials as well. In vitro bioassays were conducted to examine the acetylcholinesterase (AChE) inhibitory activity of 10 selected compounds. Results showed that there is a noticeable correlation between larvicidal activity and AChE inhibitory activity. In light of global efforts to find alternatives for currently used insecticides against disease vector mosquitoes, Pinus densiflora hydrodistillate and its constituents merit further research as potential mosquito larvicides. PMID:26464387

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

    PubMed

    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. PMID:16642384

  5. Culex mosquitoes are experimentally unable to transmit Zika virus

    PubMed Central

    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

  6. Culex mosquitoes are experimentally unable to transmit Zika virus.

    PubMed

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

    2016-09-01

    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

  7. Culex mosquitoes are experimentally unable to transmit Zika virus.

    PubMed

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

    2016-09-01

    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.

  8. Vacant Lots: Productive Sites for Aedes (Stegomyia) aegypti (Diptera: Culicidae) in Mérida City, México

    PubMed Central

    BAAK-BAAK, CARLOS M.; ARANA-GUARDIA, ROGER; CIGARROA-TOLEDO, NOHEMI; LOROÑO-PINO, MARÍA ALBA; REYES-SOLIS, GUADALUPE; MACHAIN-WILLIAMS, CARLOS; BEATY, BARRY J.; EISEN, LARS; GARCÍA-REJÓN, JULIÁN E.

    2014-01-01

    We assessed the potential for vacant lots and other non-residential settings to serve as source environments for Aedes (Stegomyia) aegypti (L.) in Mérida City, México. Mosquito immatures were collected, during November 2011 – June 2013, from residential premises (n = 156 site visits) and non-residential settings represented by vacant lots (50), parking lots (18), and streets/sidewalks (28). Collections totaled 46,025 mosquito immatures of 13 species. Ae. aegypti was the most commonly encountered species accounting for 81.0% of total immatures, followed by Culex quinquefasciatus Say (12.1%). Site visits to vacant lots (74.0%) were more likely to result in collection of Ae. aegypti immatures that residential premises (35.9%). Tires accounted for 75.5% of Ae. aegypti immatures collected from vacant lots. Our data suggest that vacant lots should be considered for inclusion in mosquito surveillance and control efforts in Mérida City, as they often are located near homes, commonly have abundant vegetation, and frequently harbor accumulations of small and large discarded water-holding containers that we now have demonstrated to serve as development sites for immature mosquitoes. Additionally, we present data for associations of immature production with various container characteristics, such as storage capacity, water quality and physical location in the environment. PMID:24724299

  9. Silencing of P-glycoprotein increases mortality in temephos-treated Aedes aegypti larvae.

    PubMed

    Figueira-Mansur, J; Ferreira-Pereira, A; Mansur, J F; Franco, T A; Alvarenga, E S L; Sorgine, M H F; Neves, B C; Melo, A C A; Leal, W S; Masuda, H; Moreira, M F

    2013-12-01

    Re-emergence of vector-borne diseases such as dengue and yellow fever, which are both transmitted by the Aedes aegypti mosquito, has been correlated with insecticide resistance. P-glycoproteins (P-gps) are ATP-dependent efflux pumps that are involved in the transport of substrates across membranes. Some of these proteins have been implicated in multidrug resistance (MDR). In this study, we identified a putative P-glycoprotein in the Ae. aegypti database based on its significantly high identity with Anopheles gambiae, Culex quinquefasciatus, Drosophila melanogaster and human P-gps. The basal ATPase activity of ATP-binding cassette transporters in larvae was significantly increased in the presence of MDR modulators (verapamil and quinidine). An eightfold increase in Ae. aegypti P-gp (AaegP-gp) gene expression was detected in temephos-treated larvae as determined by quantitative PCR. To analyse the potential role of AaegP-gp in insecticide efflux, a temephos larvicide assay was performed in the presence of verapamil. The results showed an increase of 24% in temephos toxicity, which is in agreement with the efflux reversing effect. RNA interference (RNAi)-mediated silencing of the AaegP-gp gene caused a significant increase in temephos toxicity (57%). In conclusion, we have demonstrated for the first time in insects that insecticide-induced P-gp expression can be involved in the modulation of insecticide efflux. PMID:23980723

  10. Silencing of P-glycoprotein increases mortality in temephos-treated Aedes aegypti larvae.

    PubMed

    Figueira-Mansur, J; Ferreira-Pereira, A; Mansur, J F; Franco, T A; Alvarenga, E S L; Sorgine, M H F; Neves, B C; Melo, A C A; Leal, W S; Masuda, H; Moreira, M F

    2013-12-01

    Re-emergence of vector-borne diseases such as dengue and yellow fever, which are both transmitted by the Aedes aegypti mosquito, has been correlated with insecticide resistance. P-glycoproteins (P-gps) are ATP-dependent efflux pumps that are involved in the transport of substrates across membranes. Some of these proteins have been implicated in multidrug resistance (MDR). In this study, we identified a putative P-glycoprotein in the Ae. aegypti database based on its significantly high identity with Anopheles gambiae, Culex quinquefasciatus, Drosophila melanogaster and human P-gps. The basal ATPase activity of ATP-binding cassette transporters in larvae was significantly increased in the presence of MDR modulators (verapamil and quinidine). An eightfold increase in Ae. aegypti P-gp (AaegP-gp) gene expression was detected in temephos-treated larvae as determined by quantitative PCR. To analyse the potential role of AaegP-gp in insecticide efflux, a temephos larvicide assay was performed in the presence of verapamil. The results showed an increase of 24% in temephos toxicity, which is in agreement with the efflux reversing effect. RNA interference (RNAi)-mediated silencing of the AaegP-gp gene caused a significant increase in temephos toxicity (57%). In conclusion, we have demonstrated for the first time in insects that insecticide-induced P-gp expression can be involved in the modulation of insecticide efflux.

  11. Global Perspective on the Culex pipiens Complex in the 21st Century I

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Culex pipiens complex, including Culex pipiens, Cx. quinquefasciatus, and Cx. molestus are important pest species and vectors of human and animal diseases throughout the world's tropical, temperate, and Holarctic regions. Diseases transmitted by member of the complex include: St. Louis encephali...

  12. Assessment of Local Mosquito Species Incriminates Aedes aegypti as the Potential Vector of Zika Virus in Australia

    PubMed Central

    Hall-Mendelin, Sonja; Pyke, Alyssa T.; Moore, Peter R.; Mackay, Ian M.; McMahon, Jamie L.; Ritchie, Scott A.; Taylor, Carmel T.; Moore, Frederick A.J.; van den Hurk, Andrew F.

    2016-01-01

    Background Within the last 10 years Zika virus (ZIKV) has caused unprecedented epidemics of human disease in the nations and territories of the western Pacific and South America, and continues to escalate in both endemic and non-endemic regions. We evaluated the vector competence of Australian mosquitoes for ZIKV to assess their potential role in virus transmission. Methodology/Principal Findings Mosquitoes were exposed to infectious blood meals containing the prototype African ZIKV strain. After 14 days incubation at 28°C and high relative humidity, infection, dissemination and transmission rates were assessed. Infection in Culex annulirostris and Cx. sitiens could not be detected. 8% of Cx. quinquefasciatus were infected, but the virus did not disseminate in this species. Despite having infection rates > 50%, Aedes notoscriptus and Ae. vigilax did not transmit ZIKV. In contrast, Ae. aegypti had infection and transmission rates of 57% and 27%, respectively. In susceptibility trials, the virus dose required to infect 50% (ID50) of Ae. aegypti was106.4 tissue culture infectious dose50 (TCID50)/mL. Additionally, a threshold viral load within the mosquito of at least 105.1 TCID50 equivalents/mL had to be reached before virus transmission occurred. Conclusions/Significance We confirmed Ae. aegypti to be the most likely mosquito vector of ZIKV in Australia, although the restricted distribution of this species will limit the receptive zone to northern Queensland where this species occurs. Importantly, the role in ZIKV transmission of Culex and other Aedes spp. tested will be negligible. Despite being the implicated vector, the relatively high ID50 and need for a high titer disseminated infection in Ae. aegypti suggest that high mosquito population densities will be required to facilitate epidemic ZIKV transmission among the currently immunologically naïve human population in Australia. PMID:27643685

  13. Effects of α,β-unsaturated lactones on larval survival and gut trypsin as well as oviposition response of Aedes aegypti.

    PubMed

    Barros, Maria Ester S B; Freitas, Juliano C R; Santos, Geanne K N; da Silva, Rayane Cristine Santos; Pontual, Emmanuel V; Paiva, Patrícia M G; Napoleão, Thiago H; Navarro, Daniela M A F; Menezes, Paulo H

    2015-09-01

    Lactones are organic cyclic esters that have been described as larvicides against Aedes aegypti and as components of oviposition pheromone of Culex quinquefasciatus. This work describes the effect of six α,β-unsaturated lactones (5a-5f) on survival of A. aegypti fourth instar larvae (L4). It is also reported the effects of the lactones on L4 gut trypsin activity and oviposition behavior of A. aegypti females. Five lactones were able to kill L4 being the lactones 5a (LC50 of 39.05 ppm), 5e (LC50 of 36.30 ppm) and 5f (LC50 of 40.46 ppm) the most promising larvicides. Only the lactone 5a inhibited L4 gut trypsin activity, with an IC50 of 115.15 µg/mL. Lactones 5a, 5c, 5d and 5e did not exert deterrent or stimulatory effects on oviposition, whereas lactone 5b exhibited a strong deterrent oviposition activity. In conclusion, this work introduces new α,β-unsaturated lactones as promising alternatives to control A. aegypti dissemination. The larvicidal mechanism of the lactone 5a can involve the disruption of proteolysis at larval gut.

  14. Field validation of the gravid Aedes trap (GAT) for collection of Aedes aegypti (Diptera: Culicidae).

    PubMed

    Ritchie, Scott A; Buhagiar, Tamara S; Townsend, Michael; Hoffmann, Ary; Van Den Hurk, Andrew F; McMahon, Jamie L; Eiras, Alvaro E

    2014-01-01

    Current surveillance methods for adult Aedes aegypti (L.) are expensive, require electrical power (e.g., the BG-Sentinel trap, BGS), are labor intensive (aspirators), or require difficult to use and costly adhesives (sticky ovitraps). Field trials were conducted in Cairns (Australia) to compare the efficacy of the newly designed Gravid Aedes Trap (GAT) against existing sticky ovitraps (MosquiTRAP and double sticky ovitrap) and the BGS. Latin square design trials confirmed that alarge GAT using a 9.2-liters bucket treated with Mortein Barrier Outdoor Surface Spray ([AI] 0.3 g/kg imiprothrin and 0.6 g/kg deltamethrin) outperformed a smaller 1.2-liters GAT and collected, on average, 3.7x and 2.4X more female Ae. aegypti than the MosquiTRAP and double sticky ovitrap, respectively. Field trials showed that the GAT collected 10-50% less female Ae. aegypti than the BGS trap but 30% more gravid mosquitoes than the BGS. Trials using the BGS and the GAT indicated that there was no difference in capture rates between female Ae. aegypti uninfected and infected with the wMel strain of Wolbachia, and wMel infection rates were nearly identical at >90% to field captured Ae. aegypti. The potential for the GAT to be used for dengue virus surveillance was also demonstrated with dengue virus type 3 RNA detected in five-sixths and six-sixths pools ofAe. aegypti stored in a GAT held at 28 degreeC and 60% relative humidity for 7 and 14 d, respectively. Mosquito knock down in GATs treated with Mortein surface spray set in 30, 70, and 99% shade was comparable for up to 2 mo, with only approximately 10% of adults escaping. The GAT is therefore a useful tool for capturing adult Ae. aegypti and may be suitable for other container-inhabiting species such as Aedes albopictus (Skuse) and Culex quinquefasciatus Say. The low cost and practicality of operation make the GAT suitable for vector surveillance and projects requiring monitoring of mosquitoes for Wolbachia and arboviruses, especially in

  15. Field validation of the gravid Aedes trap (GAT) for collection of Aedes aegypti (Diptera: Culicidae).

    PubMed

    Ritchie, Scott A; Buhagiar, Tamara S; Townsend, Michael; Hoffmann, Ary; Van Den Hurk, Andrew F; McMahon, Jamie L; Eiras, Alvaro E

    2014-01-01

    Current surveillance methods for adult Aedes aegypti (L.) are expensive, require electrical power (e.g., the BG-Sentinel trap, BGS), are labor intensive (aspirators), or require difficult to use and costly adhesives (sticky ovitraps). Field trials were conducted in Cairns (Australia) to compare the efficacy of the newly designed Gravid Aedes Trap (GAT) against existing sticky ovitraps (MosquiTRAP and double sticky ovitrap) and the BGS. Latin square design trials confirmed that alarge GAT using a 9.2-liters bucket treated with Mortein Barrier Outdoor Surface Spray ([AI] 0.3 g/kg imiprothrin and 0.6 g/kg deltamethrin) outperformed a smaller 1.2-liters GAT and collected, on average, 3.7x and 2.4X more female Ae. aegypti than the MosquiTRAP and double sticky ovitrap, respectively. Field trials showed that the GAT collected 10-50% less female Ae. aegypti than the BGS trap but 30% more gravid mosquitoes than the BGS. Trials using the BGS and the GAT indicated that there was no difference in capture rates between female Ae. aegypti uninfected and infected with the wMel strain of Wolbachia, and wMel infection rates were nearly identical at >90% to field captured Ae. aegypti. The potential for the GAT to be used for dengue virus surveillance was also demonstrated with dengue virus type 3 RNA detected in five-sixths and six-sixths pools ofAe. aegypti stored in a GAT held at 28 degreeC and 60% relative humidity for 7 and 14 d, respectively. Mosquito knock down in GATs treated with Mortein surface spray set in 30, 70, and 99% shade was comparable for up to 2 mo, with only approximately 10% of adults escaping. The GAT is therefore a useful tool for capturing adult Ae. aegypti and may be suitable for other container-inhabiting species such as Aedes albopictus (Skuse) and Culex quinquefasciatus Say. The low cost and practicality of operation make the GAT suitable for vector surveillance and projects requiring monitoring of mosquitoes for Wolbachia and arboviruses, especially in

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

    PubMed

    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.

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

    PubMed Central

    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

  18. Identification of Aedes aegypti Long Intergenic Non-coding RNAs and Their Association with Wolbachia and Dengue Virus Infection

    PubMed Central

    Etebari, Kayvan; Asad, Sultan; Zhang, Guangmei; Asgari, Sassan

    2016-01-01

    Long intergenic non-coding RNAs (lincRNAs) are appearing as an important class of regulatory RNAs with a variety of biological functions. The aim of this study was to identify the lincRNA profile in the dengue vector Aedes aegypti and evaluate their potential role in host-pathogen interaction. The majority of previous RNA-Seq transcriptome studies in Ae. aegypti have focused on the expression pattern of annotated protein coding genes under different biological conditions. Here, we used 35 publically available RNA-Seq datasets with relatively high depth to screen the Ae. aegypti genome for lincRNA discovery. This led to the identification of 3,482 putative lincRNAs. These lincRNA genes displayed a slightly lower GC content and shorter transcript lengths compared to protein-encoding genes. Ae. aegypti lincRNAs also demonstrate low evolutionary sequence conservation even among closely related species such as Culex quinquefasciatus and Anopheles gambiae. We examined their expression in dengue virus serotype 2 (DENV-2) and Wolbachia infected and non-infected adult mosquitoes and Aa20 cells. The results revealed that DENV-2 infection increased the abundance of a number of host lincRNAs, from which some suppress viral replication in mosquito cells. RNAi-mediated silencing of lincRNA_1317 led to enhancement in viral replication, which possibly indicates its potential involvement in the host anti-viral defense. A number of lincRNAs were also differentially expressed in Wolbachia-infected mosquitoes. The results will facilitate future studies to unravel the function of lncRNAs in insects and may prove to be beneficial in developing new ways to control vectors or inhibit replication of viruses in them. PMID:27760142

  19. Expression Profiles and RNAi Silencing of Inhibitor of Apoptosis Transcripts in Aedes, Anopheles, and Culex Mosquitoes (Diptera: Culicidae).

    PubMed

    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. PMID:26659858

  20. Expression Profiles and RNAi Silencing of Inhibitor of Apoptosis Transcripts in Aedes, Anopheles, and Culex Mosquitoes (Diptera: Culicidae).

    PubMed

    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.

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

    PubMed

    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.

  2. Culex flavivirus isolates from mosquitoes in Guatemala.

    PubMed

    Morales-Betoulle, M E; Monzón Pineda, M L; Sosa, S M; Panella, N; López, M R B; Cordón-Rosales, C; Komar, N; Powers, A; Johnson, B W

    2008-11-01

    A new strain of Culex flavivirus (family Flaviviridae, genus Flavivirus, CxFV), an insect virus first described in Japan, was isolated from adult Culex quinquefasciatus Say (Diptera: Culicidae) collected in 2006 from Izabal Department on the Caribbean coast of Guatemala. Mosquito pools were assayed for flavivirus RNA by using flavivirus group-specific primers that amplified a 720-bp region of the nonstructural (NS) 5 gene by standard reverse transcriptase-polymerase chain reaction. From 210 pools (1,699 mosquitoes), eight tested positive, and six of these mosquito pools produced virus isolates in Aedes albopictus Skuse C6/36 cells. Nucleotide sequence comparison of the eight flavivirus RNA-positive pools showed that there was 100% identity among them, and phylogenetic analysis of the NS5 and envelope gene regions indicated that they represent a strain of the recently described CxFV from Japan. This is the first report of an insect flavivirus from Central America.

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

    PubMed

    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.

  4. Identification of the Temperature Induced Larvicidal Efficacy of Agave angustifolia against Aedes, Culex, and Anopheles Larvae.

    PubMed

    Kajla, Mithilesh; Bhattacharya, Kurchi; Gupta, Kuldeep; Banerjee, Ujjwal; Kakani, Parik; Gupta, Lalita; Kumar, Sanjeev

    2015-01-01

    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 12 h. The larvicidal activity of A. 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 30 and 50°C) and it was significantly reduced during winter season (December-February, when the outside temperature falls to ~4°C or lower). Thus, we hypothesized that the larvicidal components of A. 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 A. angustifolia was induced when plants were maintained at 37°C in a semi-natural environment against the controls that were growing outside in cold weather. Pre-incubation of A. angustifolia extract at 100°C for 1 h killed 60% larvae in 12 h, which gradually increased to 100% mortality after 24 h. In addition, the dry powder formulation of A. angustifolia, also displayed a strong larvicidal activity after a long shelf life. Together, these findings revealed that A. angustifolia is an excellent source of temperature induced bioactive metabolites that may assist the preparedness for vector control programs competently. PMID:26793700

  5. Identification of the Temperature Induced Larvicidal Efficacy of Agave angustifolia against Aedes, Culex, and Anopheles Larvae

    PubMed Central

    Kajla, Mithilesh; Bhattacharya, Kurchi; Gupta, Kuldeep; Banerjee, Ujjwal; Kakani, Parik; Gupta, Lalita; Kumar, Sanjeev

    2016-01-01

    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 12 h. The larvicidal activity of A. 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 30 and 50°C) and it was significantly reduced during winter season (December–February, when the outside temperature falls to ~4°C or lower). Thus, we hypothesized that the larvicidal components of A. 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 A. angustifolia was induced when plants were maintained at 37°C in a semi-natural environment against the controls that were growing outside in cold weather. Pre-incubation of A. angustifolia extract at 100°C for 1 h killed 60% larvae in 12 h, which gradually increased to 100% mortality after 24 h. In addition, the dry powder formulation of A. angustifolia, also displayed a strong larvicidal activity after a long shelf life. Together, these findings revealed that A. angustifolia is an excellent source of temperature induced bioactive metabolites that may assist the preparedness for vector control programs competently. PMID:26793700

  6. Risk Factors for the Presence of Chikungunya and Dengue Vectors (Aedes aegypti and Aedes albopictus), Their Altitudinal Distribution and Climatic Determinants of Their Abundance in Central Nepal

    PubMed Central

    Dhimal, Meghnath; Gautam, Ishan; Joshi, Hari Datt; O’Hara, Robert B.; Ahrens, Bodo; Kuch, Ulrich

    2015-01-01

    Background The presence of the recently introduced primary dengue virus vector mosquito Aedes aegypti in Nepal, in association with the likely indigenous secondary vector Aedes albopictus, raises public health concerns. Chikungunya fever cases have also been reported in Nepal, and the virus causing this disease is also transmitted by these mosquito species. Here we report the results of a study on the risk factors for the presence of chikungunya and dengue virus vectors, their elevational ceiling of distribution, and climatic determinants of their abundance in central Nepal. Methodology/Principal Findings We collected immature stages of mosquitoes during six monthly cross-sectional surveys covering six administrative districts along an altitudinal transect in central Nepal that extended from Birgunj (80 m above sea level [asl]) to Dhunche (highest altitude sampled: 2,100 m asl). The dengue vectors Ae. aegypti and Ae. albopictus were commonly found up to 1,350 m asl in Kathmandu valley and were present but rarely found from 1,750 to 2,100 m asl in Dhunche. The lymphatic filariasis vector Culex quinquefasciatus was commonly found throughout the study transect. Physiographic region, month of collection, collection station and container type were significant predictors of the occurrence and co-occurrence of Ae. aegypti and Ae. albopictus. The climatic variables rainfall, temperature, and relative humidity were significant predictors of chikungunya and dengue virus vectors abundance. Conclusions/Significance We conclude that chikungunya and dengue virus vectors have already established their populations up to the High Mountain region of Nepal and that this may be attributed to the environmental and climate change that has been observed over the decades in Nepal. The rapid expansion of the distribution of these important disease vectors in the High Mountain region, previously considered to be non-endemic for dengue and chikungunya fever, calls for urgent actions to

  7. Effects of extract of soapnut Sapindus emarginatus on esterases and phosphatases of the vector mosquito, Aedes aegypti (Diptera: Culicidae).

    PubMed

    Koodalingam, Arunagirinathan; Mullainadhan, Periasamy; Arumugam, Munusamy

    2011-04-01

    Our earlier investigations with kernels from the soapnut Sapindus emarginatus revealed it as a new source of botanical biocide with potent antimosquito activity, as evident from the proven unique ability of the aqueous kernel extract to kill all the developmental stages of three important vector mosquito species, Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. This extract was also found to be safe for two non-target aquatic insects. As a sequel to these findings, we have further examined quantitative and qualitative changes in total proteins, esterases, and phosphatases in whole body homogenates of fourth instar larvae and pupae of A. aegypti exposed to this extract at an appropriate threshold time for its lethal effect to gain insights into the impact of the botanical biocide on biochemical characteristics of the target vector mosquito at two distinct developmental stages. The profiles of proteins, esterases (acetylcholinesterse, α- and β-carboxylesterases), and phosphatases (acid and alkaline) exhibited distinct patterns of variation during normal development of fourth instar larvae and pupae, indicating intrinsic difference in biochemical features between these two developmental stages of A. aegypti. Upon exposure of the larvae to the extract, significant reduction in the activities of acetylcholinesterse, β-carboxylesterase, and acid phosphatases were recorded, whereas the total proteins, α-carboxylesterase and alkaline phosphatase activities were unaffected. By contrast, only alkaline phosphatase activity was significantly affected in pupae exposed to the extract. Analysis of these enzymes in native PAGE revealed that they exist in isoforms in both the larvae and pupae. The alterations in the levels of enzymatic activities observed from the quantitative assays of various enzymes were reflected by the respective zymograms with perceptible differences in the intensity and the number of bands detected especially with β-carboxylesterase, acid

  8. Field evaluation of synthetic compounds mediating oviposition inCulex mosquitoes (Diptera: Culicidae).

    PubMed

    Beehler, J W; Millar, J G; Mulla, M S

    1994-02-01

    3-Methylindole (skatole), a compound shown to be an oviposition attractant/stimulant forCulex quinquefasciatus in laboratory tests, was evaluated against natural populations of mosquitoes in the field. In experiments using paired black plastic tubs that contained water treated with an attractant solution containing a mixture of 3-methylindole, 4-methylphenol, 4-ethylphenol, phenol, and indole or that contained only tap water, the attractantbaited traps received significantly moreCx. quinquefasciatus egg rafts than did the untreated tap water. Gravid female traps that were baited with attractant solution collected significantly moreCx. quinquefasciatus females than did traps containing only tap water. There was no significant difference in number ofCx. quinquefasciatus collected in the traps baited with the attractant solution compared to the traps that contained water with 3-methylindole alone, indicating that 3-methylindole was solely responsible for the attraction. In replicated experiments conducted in experimental ponds, ponds that were treated with 3-methylindole received significantly moreCx. quinquefasciatus, Cx. tarsalis, andCx. stigmatosoma egg rafts than did untreated ponds. Experimental ponds treated with 3-methylindole at two levels (0.12 and 0.6 mg/liter) were equally attractive to ovipositingCx. quinquefasciatus. This is the first record of 3-methylindole showing attractancy/stimulation to ovipositingCx. stigmatosoma andCx. tarsalis under field or laboratory conditions.

  9. Population Genetic and Admixture Analyses of Culex pipiens Complex (Diptera: Culicidae) Populations in California, United States

    PubMed Central

    Kothera, Linda; Nelms, Brittany M.; Reisen, William K.; Savage, Harry M.

    2013-01-01

    Microsatellite markers were used to genetically characterize 19 Culex pipiens complex populations from California. Two populations showed characteristics of earlier genetic bottlenecks. The overall FST value and a neighbor-joining tree suggested moderate amounts of genetic differentiation. Analyses using Structure indicated K = 4 genetic clusters: Cx. pipiens form pipiens L., Cx. quinquefasciatus Say, Cx. pipiens form molestus Forskäl, and a group of genetically similar individuals of hybrid origin. A Discriminant Analysis of Principal Components indicated that the latter group is a mixture of the other three taxa, with form pipiens and form molestus contributing somewhat more ancestry than Cx. quinquefasciatus. Characterization of 56 morphologically autogenous individuals classified most as Cx. pipiens form molestus, and none as Cx. pipiens form pipiens or Cx. quinquefasciatus. Comparison of California microsatellite data with those of Cx. pipiens pallens Coquillett from Japan indicated the latter does not contribute significantly to genotypes in California. PMID:23958909

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

    PubMed

    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.

  11. Vertical transmission of West Nile Virus by three California Culex (Diptera: Culicidae) species.

    PubMed

    Goddard, Laura B; Roth, Amy E; Reisen, William K; Scott, Thomas W

    2003-11-01

    Three California Culex species previously identified as efficient laboratory vectors of West Nile (WN) virus were tested for their capability to vertically transmit WN virus. Wild-caught Culex pipiens pipiens L., Culex pipiens quinquefasciatus Say, and two populations of Culex tarsalis Coquillett females were inoculated intrathoracically with 10(2.7 +/- 0.1) plaque-forming units of WN virus. F1 progeny were reared at 18 degrees C and subsequently tested as adults for infectious virus on Vero cell culture. Virus was not detected in 197 pools comprising 4,884 Cx. p. pipiens. The minimum filial infection rate (MFIR) for Cx. p. quinquefasciatus was approximately 3.0/1,000 for 665 progeny tested in 28 pools. There was no virus detected in 102 pools of 2,453 progeny from Cx. tarsalis collected in Riverside County. The MFIR for Cx. tarsalis collected in Yolo County was approximately 6.9/1,000 for 2,165 progeny tested in 86 pools. Mosquito progeny infected vertically during the fall could potentially serve as a mechanism for WN virus to overwinter and initiate horizontal transmission the following spring. PMID:14765647

  12. COI barcode versus morphological identification of Culex (Culex) (Diptera: Culicidae) species: a case study using samples from Argentina and Brazil.

    PubMed

    Laurito, Magdalena; Oliveira, Tatiane M P de; Almirón, Walter Ricardo; Sallum, Maria Anice Mureb

    2013-01-01

    Sequences of the cytochrome c oxidase subunit I (COI) mitochondrial gene from adults of 22 Culex (Culex) species from Argentina and Brazil were employed to assess species identification and to test the usefulness of COI for barcoding using the best close match (BCM) algorithm. A pairwise Kimura two-parameter distance matrix including the mean intra and interspecific distances for 71 COI barcode sequences was constructed. Of the 12 COI lineages recovered in the Neighbour-joining topology, five confirmed recognised morphological species (Cx. acharistus, Cx. chidesteri, Cx. dolosus, Cx. lygrus and Cx. saltanensis) with intraspecific divergences lower than 1.75%. Cx. bilineatus is formally resurrected from the synonymy of Cx. dolosus. Cx. maxi , Cx. surinamensis and the Coronator group species included were clustered into an unresolved lineage. The intraspecific distance of Cx. pipiens (3%) was almost twice the interspecific between it and Cx. quinquefasciatus (1.6%). Regarding the BCM criteria, the COI barcode successfully identified 69% of all species. The rest of the sequences, approximately 10%, 18% and 3%, remained as ambiguously, mis and unidentified, respectively. The COI barcode does not contain enough information to distinguish Culex (Cux.) species. PMID:24473810

  13. COI barcode versus morphological identification of Culex ( Culex ) (Diptera: Culicidae) species: a case study using samples from Argentina and Brazil

    PubMed Central

    Laurito, Magdalena; de Oliveira, Tatiane MP; Almirón, Walter Ricardo; Sallum, Maria Anice Mureb

    2013-01-01

    Sequences of the cytochrome c oxidase subunit I (COI) mitochondrial gene from adults of 22 Culex ( Culex ) species from Argentina and Brazil were employed to assess species identification and to test the usefulness of COI for barcoding using the best close match (BCM) algorithm. A pairwise Kimura two-parameter distance matrix including the mean intra and interspecific distances for 71 COI barcode sequences was constructed. Of the 12 COI lineages recovered in the Neighbour-joining topology, five confirmed recognised morphological species ( Cx. acharistus , Cx. chidesteri , Cx. dolosus , Cx. lygrus and Cx. saltanensis ) with intraspecific divergences lower than 1.75%. Cx. bilineatus is formally resurrected from the synonymy of Cx. dolosus . Cx. maxi , Cx. surinamensis and the Coronator group species included were clustered into an unresolved lineage. The intraspecific distance of Cx. pipiens (3%) was almost twice the interspecific between it and Cx. quinquefasciatus (1.6%). Regarding the BCM criteria, the COI barcode successfully identified 69% of all species. The rest of the sequences, approximately 10%, 18% and 3%, remained as ambiguously, mis and unidentified, respectively. The COI barcode does not contain enough information to distinguish Culex ( Cux. ) species. PMID:24473810

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

    PubMed Central

    Dehghan, Hossein; Sadraei, Javid; Moosa-Kazemi, Seyed Hassan; Abolghasemi, Esmail; Solimani, Hassan; Jaffari Nodoshan, Ahmad; Najafi, Mohammad Hassan

    2016-01-01

    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. PMID:27308288

  15. Identification of QTLs Conferring Resistance to Deltamethrin in Culex pipiens pallens

    PubMed Central

    Zhong, Daibin; Shen, Bo; Zhang, Donghui; Guo, Qin; Wang, Weijie; Yu, Jing; Lv, Yuan; Lei, Zhentao; Ma, Kai; Ma, Lei; Zhu, Changliang; Yan, Guiyun

    2015-01-01

    Culex pipiens pallens is the most abundant Culex mosquito species in northern China and is an important vector of bancroftian filariasis and West Nile virus. Deltamethrin is an insecticide that is widely used for mosquito control, however resistance to this and other insecticides has become a major challenge in the control of vector-borne diseases that appear to be inherited quantitatively. Furthermore, the genetic basis of insecticide resistance remains poorly understood. In this study, quantitative trait loci (QTL) mapping of resistance to deltamethrin was conducted in F2 intercross segregation populations using bulked segregation analysis (BSA) and amplified fragment length polymorphism markers (AFLP) in Culex pipiens pallens. A genetic linkage map covering 381 cM was constructed and a total of seven QTL responsible for resistance to deltamethrin were detected by composite interval mapping (CIM), which explained 95% of the phenotypic variance. The major QTL in linkage group 2 accounted for 62% of the variance and is worthy of further study. 12 AFLP markers in the map were cloned and the genomic locations of these marker sequences were determined by applying the Basic Local Alignment Search Tool (BLAST) tool to the genome sequence of the closely related Culex quinquefasciatus. Our results suggest that resistance to deltamethrin is a quantitative trait under the control of a major QTL in Culex pipiens pallens. Cloning of related AFLP markers confirm the potential utility for anchoring the genetic map to the physical map. The results provide insight into the genetic architecture of the trait. PMID:26484540

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

    PubMed Central

    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

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

    PubMed

    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.

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

    PubMed

    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. PMID:27605056

  19. Rapid assay to identify the two genetic forms of Culex (Culex) pipiens L. (Diptera: Culicidae) and hybrid populations.

    PubMed

    Bahnck, Carolyn M; Fonseca, Dina M

    2006-08-01

    A previously developed method to identify members of the Culex pipiens complex exploiting polymorphisms in a nuclear intron (acetylcholinesterase [ACE] based-assay) cannot differentiate the two forms of Cx. pipiens: form pipiens and form molestus. Notably, the two forms seem to differ extensively in behavior and physiology and likely have very different epidemiologic importance. Because they are morphologically indistinguishable, molecular methods are critical for the evaluation of their relative importance. Although the two forms of Cx. pipiens have been distinguished using a panel of microsatellite loci, such a protocol is laborious and expensive. We developed a rapid assay based on polymorphisms in the flanking region of a microsatellite locus. Used in conjunction with the ACE-assay, this new assay allows the identification of pure and hybrid populations of the two Cx. pipiens forms as well as those including Cx. quinquefasciatus. We discuss the usefulness of the method as well as limitations to its application. PMID:16896127

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

    PubMed

    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.

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

    PubMed Central

    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. PMID:11747732

  2. Large-Volume Gravid Traps Enhance Collection of Culex Vectors.

    PubMed

    Popko, David A; Walton, William E

    2016-06-01

    Gravid mosquito collections were compared among several large-volume (infusion volume ≥35 liters) gravid trap designs and the small-volume (infusion volume  =  6 liters) Centers for Disease Control and Prevention (CDC) gravid trap used routinely by vector control districts for vector and pathogen surveillance. The numbers of gravid Culex quinquefasciatus, Cx. tarsalis, and Cx. stigmatosoma collected by large gravid traps were greater than by the CDC gravid trap during nearly all overnight trials. Large-volume gravid traps collected on average 6.6-fold more adult female Culex mosquitoes compared to small-volume CDC gravid traps across 3 seasons during the 3 years of the studies. The differences in gravid mosquito collections between large-versus small-volume gravid traps were greatest during spring, when 8- to 56-fold more Culex individuals were collected using large-volume gravid traps. The proportion of gravid females in collections did not differ appreciably among the more effective trap designs tested. Important determinants of gravid trap performance were infusion container size and type as well as infusion volume, which determined the distance between the suction trap and the infusion surface. Of lesser importance for gravid trap performance were the number of suction traps, method of suction trap mounting, and infusion concentration. Fermentation of infusions between 1 and 4 wk weakly affected total mosquito collections, with Cx. stigmatosoma collections moderately enhanced by comparatively young and organically enriched infusions. A suction trap mounted above 100 liters of organic infusion housed in a 121-liter black plastic container collected the most gravid mosquitoes over the greatest range of experimental conditions, and a 35-liter infusion with side-mounted suction traps was a promising lesser-volume alternative design. PMID:27280347

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

    PubMed

    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.

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

    PubMed

    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.

  5. Genetic basis for reproductive diapause is correlated with life history traits within the Culex pipiens complex.

    PubMed

    Mori, A; Romero-Severson, J; Severson, D W

    2007-10-01

    The evolution of late season reproductive arrest (diapause) among female Culex pipiens mosquitoes allows them to overwinter in temperate climates, while females of the sibling species Culex quinquefasciatus do not exhibit the diapause phenotype. We present results for quantitative trait loci (QTL) analyses of two independent segregating populations derived from crosses between C. pipiens and C. quinquefasciatus. QTL for diapause and three life history traits were identified and compared for genome positions and gene effects. Using a combination of composite interval mapping, single-marker analysis and all possible subsets regression, we identified multiple QTL for each trait, totalling 14 and 17 QTL for each population, respectively. Individual QTL across traits often mapped to similar genome locations, suggesting these traits may be controlled in part by genes with pleiotropic effects or multiple tightly linked genes. The majority of QTL were intermediate in magnitude in that they explained 10-25% of the phenotypic variation. The majority of QTL showed overdominance effects. We suggest that this could impact natural populations, as increased heterosis across hybrid zones may allow populations to adapt to environmental conditions via stabilizing selection, and yet maintain species identity outside these regions because of strong morphological integration, wherein related traits evolve as an integrated unit.

  6. Analysis of Culex and Aedes mosquitoes in southwestern Nigeria revealed no West Nile virus activity

    PubMed Central

    Sule, Waidi Folorunso; Oluwayelu, Daniel Oladimeji

    2016-01-01

    Introduction Amplification and transmission of West Nile virus (WNV) by mosquitoes are driven by presence and number of viraemic/susceptible avian hosts. Methods In order to predict risk of WNV infection to humans, we collected mosquitoes from horse stables in Lagos and Ibadan, southwestern Nigeria. The mosquitoes were sorted and tested in pools with real-time RT-PCR to detect WNV (or flavivirus) RNA using WNV-specific primers and probes, as well as, pan-flavivirus-specific primers in two-step real-time RT-PCR. Minimum infection rate (MIR) was used to estimate mosquito infection rate. Results Only two genera of mosquitoes were caught (Culex, 98.9% and Aedes, 1.0%) totalling 4,112 females. None of the 424 mosquito pools tested was positive for WNV RNA; consequently the MIR was zero. Sequencing and BLAST analysis of amplicons detected in pan-flavivirus primer-mediated RT-PCR gave a consensus sequence of 28S rRNA of Culex quinquefasciatus suggesting integration of flaviviral RNA into mosquito genome. Conclusion While the latter finding requires further investigation, we conclude there was little or no risk of human infection with WNV in the study areas during sampling. There was predominance of Culex mosquito, a competent WNV vector, around horse stables in the study areas. However, mosquito surveillance needs to continue for prompt detection of WNV activity in mosquitoes. PMID:27279943

  7. Cyt1A from Bacillus thuringiensis Synergizes Activity of Bacillus sphaericus against Aedes aegypti (Diptera: Culicidae)

    PubMed Central

    Wirth, Margaret C.; Federici, Brian A.; Walton, William E.

    2000-01-01

    Bacillus sphaericus is a mosquitocidal bacterium recently developed as a commercial larvicide that is used worldwide to control pestiferous and vector mosquitoes. Whereas B. sphaericus is highly active against larvae of Culex and Anopheles mosquitoes, it is virtually nontoxic to Aedes aegypti, an important vector species. In the present study, we evaluated the capacity of the cytolytic protein Cyt1A from Bacillus thuringiensis subsp. israelensis to enhance the toxicity of B. sphaericus toward A. aegypti. Various combinations of these two materials were evaluated, and all were highly toxic. A ratio of 10:1 of B. sphaericus to Cyt1A was 3,600-fold more toxic to A. aegypti than B. sphaericus alone. Statistical analysis showed this high activity was due to synergism between the Cyt1A toxin and B. sphaericus. These results suggest that Cyt1A could be useful in expanding the host range of B. sphaericus. PMID:10698776

  8. Mosquito ovicidal properties of Ageratina adenophora (Family: Asteraceae) against filariasis vector, Culex quinquefasciatus (Diptera: Culicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mosquito-borne diseases with an economic impact create loss in commercial and labor outputs, particularly in countries with tropical and subtropical climates. Mosquito control is facing a threat because of the emergence of resistance to synthetic insecticides. Extracts from plants may be alternativ...

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

    PubMed

    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.

  10. Genetic Determinants of Differential Oral Infection Phenotypes of West Nile and St. Louis Encephalitis Viruses in Culex spp. Mosquitoes

    PubMed Central

    Maharaj, Payal D.; Bolling, Bethany G.; Anishchenko, Michael; Reisen, William K.; Brault, Aaron C.

    2014-01-01

    St. Louis encephalitis virus (SLEV) has shown greater susceptibility to oral infectivity than West Nile virus (WNV) in Culex mosquitoes. To identify the viral genetic elements that modulate these disparate phenotypes, structural chimeras (WNV–pre-membrane [prM] and envelope [E] proteins [prME]/SLEV.IC (infectious clone) and SLEV-prME/WNV.IC) were constructed in which two of the structural proteins, the prM and E, were interchanged between viruses. Oral dose–response assessment with the chimeric/parental WNV and SLEV was performed to characterize the infection phenotypes in Culex mosquitoes by artificial blood meals. The median infectious dose required to infect 50% of Cx. quinquefasciatus with WNV was indistinguishable from that of the SLEV-prME/WNV.IC chimeric virus. Similarly, SLEV and WNV-prME/SLEV.IC virus exhibited an indistinguishable oral dose–response relationship in Cx. quinquefasciatus. Infection rates for WNV.IC and SLEV-prME/WNV.IC were significantly lower than SLEV.IC and WNV-prME/SLEV.IC infection rates. These results indicated that WNV and SLEV oral infectivities are not mediated by genetic differences within the prM and E proteins. PMID:25157120

  11. Microevolution of Aedes aegypti

    PubMed Central

    Louise, Caroline; Vidal, Paloma Oliveira; Suesdek, Lincoln

    2015-01-01

    Scientific research into the epidemiology of dengue frequently focuses on the microevolution and dispersion of the mosquito Aedes aegypti. One of the world’s largest urban agglomerations infested by Ae. aegypti is the Brazilian megalopolis of Sao Paulo, where >26,900 cases of dengue were reported until June 2015. Unfortunately, the dynamics of the genetic variability of Ae. aegypti in the Sao Paulo area have not been well studied. To reduce this knowledge gap, we assessed the morphogenetic variability of a population of Ae. aegypti from a densely urbanised neighbourhood of Sao Paulo. We tested if allelic patterns could vary over a short term and if wing shape could be a predictor of the genetic variation. Over a period of 14 months, we examined the variation of genetic (microsatellites loci) and morphological (wing geometry) markers in Ae. aegypti. Polymorphisms were detected, as revealed by the variability of 20 microsatellite loci (115 alleles combined; overall Fst = 0.0358) and 18 wing landmarks (quantitative estimator Qst = 0.4732). These levels of polymorphism are higher than typically expected to an exotic species. Allelic frequencies of the loci changed over time and temporal variation in the wing shape was even more pronounced, permitting high reclassification levels of chronological samples. In spite of the fact that both markers underwent temporal variation, no correlation was detected between their dynamics. We concluded that microevolution was detected despite the short observational period, but the intensities of change of the markers were discrepant. Wing shape failed from predicting allelic temporal variation. Possibly, natural selection (Qst>Fst) or variance of expressivity of wing phenotype are involved in this discrepancy. Other possibly influential factors on microevolution of Ae. aegypti are worth searching. Additionally, the implications of the rapid evolution and high polymorphism of this mosquito vector on the efficacy of control methods

  12. Microevolution of Aedes aegypti.

    PubMed

    Louise, Caroline; Vidal, Paloma Oliveira; Suesdek, Lincoln

    2015-01-01

    Scientific research into the epidemiology of dengue frequently focuses on the microevolution and dispersion of the mosquito Aedes aegypti. One of the world's largest urban agglomerations infested by Ae. aegypti is the Brazilian megalopolis of Sao Paulo, where >26,900 cases of dengue were reported until June 2015. Unfortunately, the dynamics of the genetic variability of Ae. aegypti in the Sao Paulo area have not been well studied. To reduce this knowledge gap, we assessed the morphogenetic variability of a population of Ae. aegypti from a densely urbanised neighbourhood of Sao Paulo. We tested if allelic patterns could vary over a short term and if wing shape could be a predictor of the genetic variation. Over a period of 14 months, we examined the variation of genetic (microsatellites loci) and morphological (wing geometry) markers in Ae. aegypti. Polymorphisms were detected, as revealed by the variability of 20 microsatellite loci (115 alleles combined; overall Fst = 0.0358) and 18 wing landmarks (quantitative estimator Qst = 0.4732). These levels of polymorphism are higher than typically expected to an exotic species. Allelic frequencies of the loci changed over time and temporal variation in the wing shape was even more pronounced, permitting high reclassification levels of chronological samples. In spite of the fact that both markers underwent temporal variation, no correlation was detected between their dynamics. We concluded that microevolution was detected despite the short observational period, but the intensities of change of the markers were discrepant. Wing shape failed from predicting allelic temporal variation. Possibly, natural selection (Qst>Fst) or variance of expressivity of wing phenotype are involved in this discrepancy. Other possibly influential factors on microevolution of Ae. aegypti are worth searching. Additionally, the implications of the rapid evolution and high polymorphism of this mosquito vector on the efficacy of control methods have

  13. Merida virus, a putative novel rhabdovirus discovered in Culex and Ochlerotatus spp. mosquitoes in the Yucatan Peninsula of Mexico.

    PubMed

    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.

  14. The physiology of salinity tolerance in larvae of two species of Culex mosquitoes: the role of compatible solutes.

    PubMed

    Patrick, M L; Bradley, T J

    2000-02-01

    We investigated the physiological basis for differences in salinity tolerance ranges in mosquito larvae of the genus Culex. We examined the response of larvae of C. quinquefasciatus, a freshwater obligate, and C. tarsalis, a euryhaline osmoconformer, following transfer from fresh water to 34% sea water. Hemolymph Na(+) and Cl(-) levels increased similarly in both species, indicating that ion regulation does not differ under these conditions. C. quinquefasciatus responded to increased environmental salinity with increased hemolymph levels of serine, but suffered a significant reduction in levels of trehalose. C. tarsalis responded to increased environmental salinity with increased hemolymph levels of both proline and trehalose. When C. tarsalis larvae were held in 64% sea water, which C. quinquefasciatus larvae cannot tolerate, hemolymph proline and trehalose were accumulated approximately 50-fold and twofold, respectively, relative to freshwater values. We found that proline serves as both an intra- and extracellular compatible solute in C. tarsalis, the first such circumstance documented in an animal in response to increased environmental salinity. Analyses of the acute responses of the two species to an increase in salinity (from 30% to 50% sea water) indicate that larvae of C. tarsalis are able to volume-regulate via drinking and to attenuate increases in hemolymph NaCl concentration using unknown mechanisms during large, rapid increases in salinity. PMID:10648224

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

    PubMed

    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.

  16. Hybridization and population structure of the Culex pipiens complex in the islands of Macaronesia

    PubMed Central

    Gomes, Bruno; Alves, Joana; Sousa, Carla A; Santa-Ana, Marta; Vieira, Inês; Silva, Teresa L; Almeida, António PG; Donnelly, Martin J; Pinto, João

    2012-01-01

    The Culex pipiens complex includes two widespread mosquito vector species, Cx. pipiens and Cx. quinquefasciatus. The distribution of these species varies in latitude, with the former being present in temperate regions and the latter in tropical and subtropical regions. However, their distribution range overlaps in certain areas and interspecific hybridization has been documented. Genetic introgression between these species may have epidemiological repercussions for West Nile virus (WNV) transmission. Bayesian clustering analysis based on multilocus genotypes of 12 microsatellites was used to determine levels of hybridization between these two species in Macaronesian islands, the only contact zone described in West Africa. The distribution of the two species reflects both the islands' biogeography and historical aspects of human colonization. Madeira Island displayed a homogenous population of Cx. pipiens, whereas Cape Verde showed a more intriguing scenario with extensive hybridization. In the islands of Brava and Santiago, only Cx. quinquefasciatus was found, while in Fogo and Maio high hybrid rates (∼40%) between the two species were detected. Within the admixed populations, second-generation hybrids (∼50%) were identified suggesting a lack of isolation mechanisms. The observed levels of hybridization may locally potentiate the transmission to humans of zoonotic arboviruses such as WNV. PMID:22957190

  17. Characterization of Culex pipiens complex (Diptera: Culicidae) populations in Colorado, USA using microsatellites.

    PubMed

    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 (H(E)) 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 F(ST) 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.

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

    PubMed Central

    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

  19. Temperature and water quality effects in simulated woodland pools on the infection of Culex mosquito larvae by Lagenidium giganteum (Oomycetes: Lagenidiales) in North Carolina

    SciTech Connect

    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.

  20. Effects of warm winter temperature on the abundance and gonotrophic activity of Culex (Diptera: Culicidae) in California.

    PubMed

    Reisen, William K; Thiemann, Tara; Barker, Christopher M; Lu, Helen; Carroll, Brian; Fang, Ying; Lothrop, Hugh D

    2010-03-01

    Culex tarsalis Coquillett, Cx. quinquefasciatus Say, and Cx. pipiens L. were collected during the warm winter of 2009 using dry ice-baited and gravid traps and walk-in red boxes positioned in desert, urban, and agricultural habitats in Riverside, Los Angeles, Kern, and Yolo Counties. Temperatures exceeded the preceding 50 yr averages in all locations for most of January, whereas rainfall was absent or below average. Abundance of Culex species in traps during January ranged from 83 to 671% of the prior 5 yr average in all locations. Few females collected resting were in diapause during January based on follicular measurements. Evidence for early season gonotrophic activity included the detection of freshly bloodfed, gravid, and parous females in resting collections, gravid oviposition site-seeking females in gravid female traps, and nulliparous and parous host-seeking females at dry ice-baited traps. Female Culex seemed to employ multiple overwintering strategies in California, including larval and adult quiescence, adult female diapause, and an intermediate situation with adult females collected with enlarged follicles, but without evident vitellogenesis. West Nile, St. Louis, or western equine encephalitis viruses were not detected in 198 pools of adults or 56 pools of adults reared from field-collected immatures collected during January and February 2009. Our preliminary data may provide insight into how climate change may extend the mosquito season in California. PMID:20380305

  1. Bromeliad-inhabiting mosquitoes in an urban botanical garden of dengue endemic Rio de Janeiro. Are bromeliads productive habitats for the invasive vectors Aedes aegypti and Aedes albopictus?

    PubMed Central

    Mocellin, Márcio Goulart; Simões, Taynãna César; do Nascimento, Teresa Fernandes Silva; Teixeira, Maria Lucia França; Lounibos, Leon Philip; de Oliveira, Ricardo Lourenço

    2012-01-01

    Immatures of both Aedes aegypti and Aedes albopictus have been found in water-holding bromeliad axils in Brazil. Removal of these plants or their treatment with insecticides in public and private gardens have been undertaken during dengue outbreaks in Brazil despite uncertainty as to their importance as productive habitats for dengue vectors. From March 2005-February 2006, we sampled 120 randomly selected bromeliads belonging to 10 species in a public garden less than 200 m from houses in a dengue-endemic neighborhood in Rio de Janeiro. A total of 2,816 mosquito larvae and pupae was collected, with an average of 5.87 immatures per plant per collection. Culex (Microculex) pleuristriatus and Culex spp of the Ocellatus Group were the most abundant culicid species, found in all species of bromeliads; next in relative abundance were species of the genus Wyeomyia. Only two individuals of Ae. aegypti (0.07%) and five of Ae. albopictus (0.18%) were collected from bromeliads. By contrast, immatures of Ae. aegypti were found in manmade containers in nearly 5% of nearby houses. These results demonstrate that bromeliads are not important producers of Ae. aegypti and Ae. albopictus and, hence, should not be a focus for dengue control. However, the results of this study of only one year in a single area may not represent outcomes in other urban localities where bromeliads, Ae. aegypti and dengue coincide in more disturbed habitats. PMID:20140379

  2. Comparative transcriptome analyses of deltamethrin-susceptible and -resistant Culex pipiens pallens by RNA-seq.

    PubMed

    Lv, Yuan; Wang, Weijie; Hong, Shanchao; Lei, Zhentao; Fang, Fujin; Guo, Qin; Hu, Shengli; Tian, Mengmeng; Liu, Bingqian; Zhang, Donghui; Sun, Yan; Ma, Lei; Shen, Bo; Zhou, Dan; Zhu, Changliang

    2016-02-01

    The widespread and improper use of pyrethroid insecticides, such as deltamethrin, has resulted in the evolution of resistance in many mosquito species, including Culex pipiens pallens. With the development of high-throughput sequencing, it is possible to massively screen pyrethroid resistance-associated gene. In this study, we used Illumina-Solexa transcriptome sequencing to identify genes that are expressed differently in deltamethrin-susceptible and -resistant strains of Culex pipiens pallens as a critical knowledge base for further studies. A total of 4,961,197,620 base pairs and 55,124,418 reads were sequenced, mapped to the Culex quinquefasciatus genome and assembled into 17,679 known genes. We recorded 1826 significantly differentially expressed genes (DEGs). Among them, 1078 genes were up-regulated and 748 genes were down-regulated in the deltamethrin-resistant strain compared to -susceptible strain. These DEGs contained cytochrome P450 s, cuticle proteins, UDP-glucuronosyltransferases, lipases, serine proteases, heat shock proteins, esterases and others. Among the 1826 DEGs, we found that the transcriptional levels of CYP6AA9 in the laboratory populations was elevated as the levels of deltamethrin resistance increased. Moreover, the expression levels of the CYP6AA9 were significantly higher in the resistant strains than the susceptible strains in three different field populations. We further confirmed the association between the CYP6AA9 gene and deltamethrin resistance in mosquitoes by RNA interfering (RNAi). Altogether, we explored massive potential pyrethroid resistance-associated genes and demonstrated that CYP6AA9 participated in the pyrethroid resistance in mosquitoes.

  3. Aedes aegypti genomics.

    PubMed

    Severson, David W; Knudson, Dennis L; Soares, Marcelo B; Loftus, Brendan J

    2004-07-01

    The mosquito, Aedes aegypti, is the primary, worldwide arthropod vector for the yellow fever and dengue viruses. As it is also one of the most tractable mosquito species for laboratory studies, it has been and remains one of the most intensively studied arthropod species. This has resulted in the development of detailed genetic and physical maps for Ae. aegypti and considerable insight into its genome organization. The research community is well-advanced in developing important molecular tools that will facilitate a whole genome sequencing effort. This includes generation of BAC clone end sequences, physical mapping of selected BAC clones and generation of EST sequences. Whole genome sequence information for Ae. aegypti will provide important insight into mosquito chromosome evolution and allow for the identification of genes and gene function. These functions may be common to all mosquitoes or perhaps unique to individual species, possibly specific to host-seeking and blood-feeding behaviors, as well as the innate immune response to pathogens encountered during blood-feeding. This information will be invaluable to the global effort to develop novel strategies for preventing arthropod-borne disease transmission.

  4. Flavivirus susceptibility in Aedes aegypti.

    PubMed

    Black, William C; Bennett, Kristine E; Gorrochótegui-Escalante, Norma; Barillas-Mury, Carolina V; Fernández-Salas, Ildefonso; de Lourdes Muñoz, María; Farfán-Alé, José A; Olson, Ken E; Beaty, Barry J

    2002-01-01

    Aedes aegypti is the primary vector of yellow fever (YF) and dengue fever (DF) flaviviruses worldwide. In this review we focus on past and present research on genetic components and environmental factors in Aedes aegypti that appear to control flavivirus transmission. We review genetic relationships among Ae. aegypti populations throughout the world and discuss how variation in vector competence is correlated with overall genetic differences among populations. We describe current research into how genetic and environmental factors jointly affect distribution of vector competence in natural populations. Based on this information, we propose a population genetic model for vector competence and discuss our recent progress in testing this model. We end with a discussion of approaches being taken to identify the genes that may control flavivirus susceptibility in Ae. aegypti.

  5. Reverse and Conventional Chemical Ecology Approaches for the Development of Oviposition Attractants for Culex Mosquitoes

    PubMed Central

    Leal, Walter S.; Barbosa, Rosângela M. R.; Xu, Wei; Ishida, Yuko; Syed, Zainulabeuddin; Latte, Nicolas; Chen, Angela M.; Morgan, Tania I.; Cornel, Anthony J.; Furtado, André

    2008-01-01

    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 µg/l) and nonanal (0.15 ng/µl) 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. PMID:18725946

  6. Bromeliad-inhabiting mosquitoes in an urban botanical garden of dengue endemic Rio de Janeiro--are bromeliads productive habitats for the invasive vectors Aedes aegypti and Aedes albopictus?

    PubMed

    Mocellin, Márcio Goulart; Simões, Taynãna César; Nascimento, Teresa Fernandes Silva do; Teixeira, Maria Lucia França; Lounibos, Leon Philip; Oliveira, Ricardo Lourenço de

    2009-12-01

    Immatures of both Aedes aegypti and Aedes albopictus have been found in water-holding bromeliad axils in Brazil. Removal of these plants or their treatment with insecticides in public and private gardens have been undertaken during dengue outbreaks in Brazil despite uncertainty as to their importance as productive habitats for dengue vectors. From March 2005-February 2006, we sampled 120 randomly selected bromeliads belonging to 10 species in a public garden less than 200 m from houses in a dengue-endemic neighborhood in Rio de Janeiro. A total of 2,816 mosquito larvae and pupae was collected, with an average of 5.87 immatures per plant per collection. Culex (Microculex) pleuristriatus and Culex spp of the Ocellatus Group were the most abundant culicid species, found in all species of bromeliads; next in relative abundance were species of the genus Wyeomyia. Only two individuals of Ae. aegypti (0.07%) and five of Ae. albopictus(0.18%) were collected from bromeliads. By contrast, immatures of Ae. aegypti were found in manmade containers in nearly 5% of nearby houses. These results demonstrate that bromeliads are not important producers of Ae. aegypti and Ae. albopictus and, hence, should not be a focus for dengue control. However, the results of this study of only one year in a single area may not represent outcomes in other urban localities where bromeliads, Ae. aegypti and dengue coincide in more disturbed habitats.

  7. Temporal genetic stability of Stegomyia aegypti (= Aedes aegypti) populations.

    PubMed

    Gloria-Soria, A; Kellner, D A; Brown, J E; Gonzalez-Acosta, C; Kamgang, B; Lutwama, J; Powell, J R

    2016-06-01

    The mosquito Stegomyia aegypti (= Aedes aegypti) (Diptera: Culicidae) is the primary vector of viruses that cause yellow fever, dengue and Chikungunya fever. In the absence of effective vaccines, the reduction of these diseases relies on vector control strategies. The success of these strategies is tightly linked to the population dynamics of target populations. In the present study, 14 collections from St. aegypti populations separated by periods of 1-13 years were analysed to determine their temporal genetic stability. Although temporal structure is discernible in most populations, the degree of temporal differentiation is dependent on the population and does not obscure the geographic structure of the various populations. The results suggest that performing detailed studies in the years prior to and after population reduction- or modification-based control interventions at each target field site may be useful in assessing the probability of success. PMID:26744174

  8. Temporal genetic stability of Stegomyia aegypti (= Aedes aegypti) populations.

    PubMed

    Gloria-Soria, A; Kellner, D A; Brown, J E; Gonzalez-Acosta, C; Kamgang, B; Lutwama, J; Powell, J R

    2016-06-01

    The mosquito Stegomyia aegypti (= Aedes aegypti) (Diptera: Culicidae) is the primary vector of viruses that cause yellow fever, dengue and Chikungunya fever. In the absence of effective vaccines, the reduction of these diseases relies on vector control strategies. The success of these strategies is tightly linked to the population dynamics of target populations. In the present study, 14 collections from St. aegypti populations separated by periods of 1-13 years were analysed to determine their temporal genetic stability. Although temporal structure is discernible in most populations, the degree of temporal differentiation is dependent on the population and does not obscure the geographic structure of the various populations. The results suggest that performing detailed studies in the years prior to and after population reduction- or modification-based control interventions at each target field site may be useful in assessing the probability of success.

  9. Occurrence and phylogenetic characterization of a baculovirus isolated from Culex quinquefasciatus in São Paulo State, Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Baculoviruses are microbial agents that affects mosquito and lepidoptera larvae. They are characterized by rod-shaped virions containing circular double-stranded DNA and are the most studied insect viruses, due to their role as biological pesticides. The aim of this study was to assess the occurrenc...

  10. Evaluation of several novel alkynols, alkenols, and selected host odor blends as attractants to female Aedes albopictus and Culex quinquefasciatus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The compound 1-octen-3-ol is a strong attractant for some mosquito species. Based on chemical structure, this may be due to a terminal site of unsaturation or high electron density, a structural capability for hydrogen bonding e.g. -OH, -NH2, NHR, NR2 etc., a saturated hydrocarbon chain of a cer...

  11. Ingestion of the epoxide hydrolase inhibitor AUDA modulates immune responses of the mosquito, Culex quinquefasciatus during blood feeding.

    PubMed

    Xu, Jiawen; Morisseau, Christophe; Yang, Jun; Lee, Kin Sing Stephen; Kamita, Shizuo G; Hammock, Bruce D

    2016-09-01

    Epoxide hydrolases (EHs) are enzymes that play roles in metabolizing xenobiotic epoxides from the environment, and in regulating lipid signaling molecules, such as juvenile hormones in insects and epoxy fatty acids in mammals. In this study we fed mosquitoes with an epoxide hydrolase inhibitor AUDA during artificial blood feeding, and we found the inhibitor increased the concentration of epoxy fatty acids in the midgut of female mosquitoes. We also observed ingestion of AUDA triggered early expression of defensin A, cecropin A and cecropin B2 at 6 h after blood feeding. The expression of cecropin B1 and gambicin were not changed more than two fold compared to controls. The changes in gene expression were transient possibly because more than 99% of the inhibitor was metabolized or excreted at 42 h after being ingested. The ingestion of AUDA also affected the growth of bacteria colonizing in the midgut, but did not affect mosquito longevity, fecundity and fertility in our laboratory conditions. When spiked into the blood, EpOMEs and DiHOMEs were as effective as the inhibitor AUDA in reducing the bacterial load in the midgut, while EETs rescued the effects of AUDA. Our data suggest that epoxy fatty acids from host blood are immune response regulators metabolized by epoxide hydrolases in the midgut of female mosquitoes, inhibition of which causes transient changes in immune responses, and affects growth of microbes in the midgut. PMID:27369469

  12. Application site and adult age impact on the efficacy of two topically-applied insecticides to Culex quinquefasciatus Say

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insecticide droplets will impact the mosquito body, but little is known about the interaction of these droplets to a mosquito as it is flying through the air. Droplets of insecticide were applied to the mosquito body in order to determine if a droplet of insecticide will kill a mosquito when it com...

  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.

    PubMed

    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. Identity and transfer of male reproductive gland proteins of the dengue vector mosquito, Aedes aegypti: potential tools for control of female feeding and reproduction.

    PubMed

    Sirot, Laura K; Poulson, Rebecca L; McKenna, M Caitlin; Girnary, Hussein; Wolfner, Mariana F; Harrington, Laura C

    2008-02-01

    Male reproductive gland proteins (mRGPs) impact the physiology and/or behavior of mated females in a broad range of organisms. We sought to identify mRGPs of the yellow fever mosquito, Aedes aegypti, the primary vector of dengue and yellow fever viruses. Earlier studies with Ae. aegypti demonstrated that "matrone" (a partially purified male reproductive accessory gland substance) or male accessory gland fluid injected into virgin female Ae. aegypti affect female sexual refractoriness, blood feeding and digestion, flight, ovarian development, and oviposition. Using bioinformatic comparisons to Drosophila melanogaster accessory gland proteins and mass spectrometry of proteins from Ae. aegypti male accessory glands and ejaculatory ducts (AG/ED) and female reproductive tracts, we identified 63 new putative Ae. aegypti mRGPs. Twenty-one of these proteins were found in the reproductive tract of mated females but not of virgin females suggesting that they are transferred from males to females during mating. Most of the putative mRGPs fall into the same protein classes as mRGPs in other organisms, although some appear to be evolving rapidly and lack identifiable homologs in Culex pipiens, Anopheles gambiae, and D. melanogaster. Our results identify candidate male-derived molecules that may have an important influence on behavior, survival, and reproduction of female mosquitoes.

  15. Green synthesis of silver nanoparticles for the control of mosquito disease vectors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A biological method was used to synthesize stable silver nanoparticles. The nanoparticles were tested as larvicides against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. Annona squamosa leaf broth (5%) reduced aqueous AgNO3 to stable silver nanoparticles with average particle siz...

  16. Mosquitocidal and water purification properties of Cynodon dactylon, Aloe vera, Hemidesmus indicus and Coleus amboinicus leaf extracts.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ethanolic extracts of Cynodon dactylon, Aloe vera, Hemidesmus indicus and Coleus amboinicus were tested for toxicity to 3rd instar Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti. Median lethal concentrations (LC50) were, respectively, 0.44%, 0.51%, 0.59% and 0.68%. Cynodon dactylon...

  17. Insecticide tolerance of Culex nigripalpus in Florida.

    PubMed

    Boike, A H; Rathburn, C B; Floore, T G; Rodriguez, H M; Coughlin, J S

    1989-12-01

    Larval susceptibility tests of Culex nigripalpus populations from various areas of Florida have shown resistance to several organophosphorus insecticides since 1984. Although the degree of resistance is low (2 to 7 times), it can be termed tolerance and appears to be the greatest for fenthion, followed by temephos, naled and malathion. It is suggested that pesticide runoff from lawns, golf courses and agricultural and urban areas may play a role in developing resistance in Florida mosquito populations. PMID:2614401

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

    PubMed

    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.

  19. “BIRD BITING” MOSQUITOES AND HUMAN DISEASE: A REVIEW OF THE ROLE OF CULEX PIPIENS COMPLEX MOSQUITOES IN EPIDEMIOLOGY

    PubMed Central

    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

  20. Workbook on Identification of Aedes Aegypti Larvae.

    ERIC Educational Resources Information Center

    Pratt, Harry D.; And Others

    This self-instructional booklet is designed to enable yellow fever control workers to identify the larvae of "Aedes aegypti." The morphological features of mosquito larvae are illustrated in this partially programed text, and the distinguishing features of "A. aegypti" indicated. A glossary is included. (AL)

  1. Sterculia guttata seeds extractives--an effective mosquito larvicide.

    PubMed

    Katade, Sushama R; Pawar, Pushpa V; Wakharkar, Radhika D; Deshpande, Nirmala R

    2006-08-01

    The larvicidal activity of ethanol, chloroform and hexane soxhlet extracts obtained from S. guttata seeds was investigated against the IVth instar larvae of Dengue fever vector, Aedes aegypti and filarial vector, Culex quinquefasciatus. All extracts including fractions of ethanol extract exhibited 100% larval kill within 24 hr exposure period at 500 ppm concentration. Fraction A1 of ethanol was found to be most promising; its LC50 was 21.552 and 35.520 ppm against C. quinquefasciatus and A. aegypti respectively. Naturally occurring S. guttata seed derived fractions merit further study as potential mosquito larval control agents or lead compounds.

  2. A Sequence of Flushing and Drying of Breeding Habitats of Aedes aegypti (L.) Prior to the Low Dengue Season in Singapore

    PubMed Central

    Seidahmed, Osama M. E.; Eltahir, Elfatih A. B.

    2016-01-01

    In dengue-endemic areas, transmission shows both a seasonal and interannual variability. To investigate how rainfall impacts dengue seasonality in Singapore, we carried out a longitudinal survey in the Geylang neighborhood from August 2014 to August 2015. The survey comprised of twice-weekly random inspections to outdoor breeding habitats and continuous monitoring for positive ones. In addition, observations of rainstorms were collected. Out of 6824 inspected habitats, 67 contained Aedes aegypti, 11 contained Aedes albopictus and 24 contained Culex spp. The main outdoors habitat of Aedes aegypti was storm drains (54/67). We found that 80% of breeding sites in drains (43/54) were lost after intense rainstorms related to the wet phase of the Northeast monsoon (NE) between November 2014 and early January 2015. Subsequently, 95% (41/43) of these flushed drains had dried out during the dry phase of the NE in late January-February 2015. A return in the outdoor breeding of Aedes aegypti was observed after the onset of Southwest monsoon (SW) between May and August 2015. There was also a reduction in productivity of breeding habitats for larvae and pupae after the onset of the NE. In wet equatorial regions like Singapore, rainfall varies with the monsoons. A monsoon-driven sequence of flushing and drying shapes the outdoor seasonal abundance of Aedes aegypti. This finding can be used to optimize vector control strategies and better understand dengue in the context of climate change. PMID:27459322

  3. A Sequence of Flushing and Drying of Breeding Habitats of Aedes aegypti (L.) Prior to the Low Dengue Season in Singapore.

    PubMed

    Seidahmed, Osama M E; Eltahir, Elfatih A B

    2016-07-01

    In dengue-endemic areas, transmission shows both a seasonal and interannual variability. To investigate how rainfall impacts dengue seasonality in Singapore, we carried out a longitudinal survey in the Geylang neighborhood from August 2014 to August 2015. The survey comprised of twice-weekly random inspections to outdoor breeding habitats and continuous monitoring for positive ones. In addition, observations of rainstorms were collected. Out of 6824 inspected habitats, 67 contained Aedes aegypti, 11 contained Aedes albopictus and 24 contained Culex spp. The main outdoors habitat of Aedes aegypti was storm drains (54/67). We found that 80% of breeding sites in drains (43/54) were lost after intense rainstorms related to the wet phase of the Northeast monsoon (NE) between November 2014 and early January 2015. Subsequently, 95% (41/43) of these flushed drains had dried out during the dry phase of the NE in late January-February 2015. A return in the outdoor breeding of Aedes aegypti was observed after the onset of Southwest monsoon (SW) between May and August 2015. There was also a reduction in productivity of breeding habitats for larvae and pupae after the onset of the NE. In wet equatorial regions like Singapore, rainfall varies with the monsoons. A monsoon-driven sequence of flushing and drying shapes the outdoor seasonal abundance of Aedes aegypti. This finding can be used to optimize vector control strategies and better understand dengue in the context of climate change.

  4. A Sequence of Flushing and Drying of Breeding Habitats of Aedes aegypti (L.) Prior to the Low Dengue Season in Singapore.

    PubMed

    Seidahmed, Osama M E; Eltahir, Elfatih A B

    2016-07-01

    In dengue-endemic areas, transmission shows both a seasonal and interannual variability. To investigate how rainfall impacts dengue seasonality in Singapore, we carried out a longitudinal survey in the Geylang neighborhood from August 2014 to August 2015. The survey comprised of twice-weekly random inspections to outdoor breeding habitats and continuous monitoring for positive ones. In addition, observations of rainstorms were collected. Out of 6824 inspected habitats, 67 contained Aedes aegypti, 11 contained Aedes albopictus and 24 contained Culex spp. The main outdoors habitat of Aedes aegypti was storm drains (54/67). We found that 80% of breeding sites in drains (43/54) were lost after intense rainstorms related to the wet phase of the Northeast monsoon (NE) between November 2014 and early January 2015. Subsequently, 95% (41/43) of these flushed drains had dried out during the dry phase of the NE in late January-February 2015. A return in the outdoor breeding of Aedes aegypti was observed after the onset of Southwest monsoon (SW) between May and August 2015. There was also a reduction in productivity of breeding habitats for larvae and pupae after the onset of the NE. In wet equatorial regions like Singapore, rainfall varies with the monsoons. A monsoon-driven sequence of flushing and drying shapes the outdoor seasonal abundance of Aedes aegypti. This finding can be used to optimize vector control strategies and better understand dengue in the context of climate change. PMID:27459322

  5. Urban mosquito species (Diptera: Culicidae) of dengue endemic communities in the Greater Puntarenas area, Costa Rica.

    PubMed

    Calderón-Arguedas, Olger; Troyo, Adriana; Solano, Mayra E; Avendaño, Adrián; Beier, John C

    2009-12-01

    Field studies were conducted to determine the mosquito species richness in the urban area of Greater Puntarenas in Costa Rica. Two cross-sectional entomological surveys were performed in seven localities of Puntarenas: one survey was performed during the wet season and the other during the dry season. The sections evaluated were determined by applying a stratified cluster sampling method using satellite imagery, and a sample of 26 cells (100 x 100m) was selected for the study. The number of cells per locality was proportional to the area of each locality. The presence of mosquito larvae and pupae in water-filled artificial and natural containers was determined in each cell. Infestation was expressed as a diversity index per type of container (Ii). Eight types of larvae were identified (Aedes aegypti, Culex quinquefasciatus, Culex interrogator, Culex nigripalpus, Culex corniger, Culex tarsalis, Limatus durhamii and Toxorhynchites theobaldi) and in two cases it was only possible to identify the genus (Culex sp. and Uranotaenia sp.). A. aegypti was the most common species followed by C. quinquefascitus. Diversity of wet environments can explain the co-occurrence of various culicid species in some localities. Although A. aegypti is the only documented disease vector in the area, C quinquefasciatus, C nigripalpus, and the other species of Culex could be considered potential vectors of other pathogens. The presence and ecology of all mosquito species should be studied to optimize surveillance and prevention of dengue and to prevent the emergence of other mosquito-transmitted diseases.

  6. Urban mosquito species (Diptera: Culicidae) of dengue endemic communities in the Greater Puntarenas area, Costa Rica

    PubMed Central

    Troyo, Adriana; Solano, Mayra E.; Avendaño, Adrián; Beier, John C.

    2010-01-01

    Field studies were conducted to determine the mosquito species richness in the urban area of Greater Puntarenas in Costa Rica. Two cross-sectional entomological surveys were performed in seven localities of Puntarenas: one survey was performed during the wet season and the other during the dry season. The sections evaluated were determined by applying a stratified cluster sampling method using satellite imagery, and a sample of 26 cells (100×100m) was selected for the study. The number of cells per locality was proportional to the area of each locality. The presence of mosquito larvae and pupae in water-filled artificial and natural containers was determined in each cell. Infestation was expressed as a diversity index per type of container (Ii). Eight types of larvae were identified (Aedes aegypti, Culex quinquefasciatus, Culex interrogator, Culex nigripalpus, Culex corniger, Culex tarsalis, Limatus durhamii and Toxorhynchites theobaldi) and in two cases it was only possible to identify the genus (Culex sp. and Uranotaenia sp.). A. aegypti was the most common species followed by C. quinquefascitus. Diversity of wet environments can explain the co-occurrence of various culicid species in some localities. Although A. aegypti is the only documented disease vector in the area, C quinquefasciatus, C. nigripalpus, and the other species of Culex could be considered potential vectors of other pathogens. The presence and ecology of all mosquito species should be studied to optimize surveillance and prevention of dengue and to prevent the emergence of other mosquito-transmitted diseases. PMID:20073347

  7. Urban mosquito species (Diptera: Culicidae) of dengue endemic communities in the Greater Puntarenas area, Costa Rica.

    PubMed

    Calderón-Arguedas, Olger; Troyo, Adriana; Solano, Mayra E; Avendaño, Adrián; Beier, John C

    2009-12-01

    Field studies were conducted to determine the mosquito species richness in the urban area of Greater Puntarenas in Costa Rica. Two cross-sectional entomological surveys were performed in seven localities of Puntarenas: one survey was performed during the wet season and the other during the dry season. The sections evaluated were determined by applying a stratified cluster sampling method using satellite imagery, and a sample of 26 cells (100 x 100m) was selected for the study. The number of cells per locality was proportional to the area of each locality. The presence of mosquito larvae and pupae in water-filled artificial and natural containers was determined in each cell. Infestation was expressed as a diversity index per type of container (Ii). Eight types of larvae were identified (Aedes aegypti, Culex quinquefasciatus, Culex interrogator, Culex nigripalpus, Culex corniger, Culex tarsalis, Limatus durhamii and Toxorhynchites theobaldi) and in two cases it was only possible to identify the genus (Culex sp. and Uranotaenia sp.). A. aegypti was the most common species followed by C. quinquefascitus. Diversity of wet environments can explain the co-occurrence of various culicid species in some localities. Although A. aegypti is the only documented disease vector in the area, C quinquefasciatus, C nigripalpus, and the other species of Culex could be considered potential vectors of other pathogens. The presence and ecology of all mosquito species should be studied to optimize surveillance and prevention of dengue and to prevent the emergence of other mosquito-transmitted diseases. PMID:20073347

  8. Breeding Sites of Aedes aegypti: Potential Dengue Vectors in Dire Dawa, East Ethiopia

    PubMed Central

    Getachew, Dejene; Tekie, Habte; Gebre-Michael, Teshome; Balkew, Meshesha; Mesfin, Akalu

    2015-01-01

    Background and Objectives. Entomological survey was carried out from May-June to September-October 2014 to investigate the presence of dengue vectors in discarded tires and artificial water containers in houses and peridomestic areas. Methods. A cross-sectional immature stage survey was done indoors and outdoors in 301 houses. Mosquito larval sampling was conducted using pipette or dipper depending on container types. Larvae were identified morphologically and larval indices were also calculated. Results. A total of 750 containers were inspected, and of these 405 were positive for mosquito larvae. A total of 1,873 larvae were collected and morphologically identified as Aedes aegypti (n = 1580: 84.4%) and Culex (n = 293: 15.6%). The larval indices, house index, container index, and breteau index, varied from 33.3 to 86.2, from 23.2 to 73.9, and from 56.5 to 188.9, respectively. Conclusion. Aedes aegypti is breeding in a wide range of artificial containers. To control these mosquitoes, the integration of different methods should be taken into consideration. PMID:26435712

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

    PubMed

    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.

  10. Functional characterization of an arrestin gene on insecticide resistance of Culex pipiens pallens

    PubMed Central

    2012-01-01

    Background Continuous and excessive application of insecticides has resulted in the rapid development of insecticide resistance in several mosquito species, including Culex pipiens pallens. Previous studies in our laboratory found that arrestin gene expression was higher in the deltamethrin-resistant (DR) strain than in the deltamethrin-susceptible (DS) strain of Cx. pipiens pallens. Similarly, other studies reported that arrestin was highly expressed in permethrin-resistant Cx. quinquefasciatus and in dichlorodiphenyltrichloroethane (DDT)-resistant Drosophila melanogaster. Methods Full-length cDNAs of an arrestin gene were cloned from Cx. pipiens pallens via polymerase chain reaction (PCR) and rapid amplification of cDNA end (RACE). The mRNA levels of the arrestin gene in the whole life cycle of DR and DS strains of Cx. pipiens pallens were investigated via quantitative real-time PCR. In addition, the relationship between arrestin and deltamethrin (DM) resistance were identified using genetic overexpression strategies and arrestin RNAi in mosquito cells. Cell viability was analyzed with cholecystokinin octapeptide after DM treatment. Moreover, the mRNA levels of cytochrome P450 6A1 (CYP6A1) and opsin in the transfected cells and controls were analyzed. Results Complete arrestin gene sequence was cloned and expressed throughout the life cycle of Cx. pipiens pallens. Moreover, arrestin was significantly upregulated in the DR strain, compared with that in the DS strain at the egg, pupae, and adult stages. Arrestin overexpression comparably increased the mosquito cell viability, whereas arrestin knockdown by siRNA decreased mosquito cell viability with deltamethrin (DM) treatment. Meanwhile, the mRNA levels of CYP6A1 and opsin were upregulated in mosquito cells transfected with arrestin and downregulated in mosquito cells with arrestin knockdown. Conclusion This study presented the first evidence that arrestin might be associated with insecticide resistance in Cx

  11. Common Culex Mosquitoes Don't Transmit Zika Virus

    MedlinePlus

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

  12. Thiosemicarbazones as Aedes aegypti larvicidal.

    PubMed

    da Silva, João Bosco P; Navarro, Daniela Maria do A F; da Silva, Aluizio G; Santos, Geanne K N; Dutra, Kamilla A; Moreira, Diogo Rodrigo; Ramos, Mozart N; Espíndola, José Wanderlan P; de Oliveira, Ana Daura T; Brondani, Dalci José; Leite, Ana Cristina L; Hernandes, Marcelo Zaldini; Pereira, Valéria R A; da Rocha, Lucas F; de Castro, Maria Carolina A B; de Oliveira, Beatriz C; Lan, Que; Merz, Kenneth M

    2015-07-15

    A set of aryl- and phenoxymethyl-(thio)semicarbazones were synthetized, characterized and biologically evaluated against the larvae of Aedes aegypti (A. aegypti), the vector responsible for diseases like Dengue and Yellow Fever. (Q)SAR studies were useful for predicting the activities of the compounds not included to create the QSAR model as well as to predict the features of a new compound with improved activity. Docking studies corroborated experimental evidence of AeSCP-2 as a potential target able to explain the larvicidal properties of its compounds. The trend observed between the in silico Docking scores and the in vitro pLC50 (equals -log LC50, at molar concentration) data indicated that the highest larvicidal compounds, or the compounds with the highest values for pLC50, are usually those with the higher docking scores (i.e., greater in silico affinity for the AeSCP-2 target). Determination of cytotoxicity for these compounds in mammal cells demonstrated that the top larvicide compounds are non-toxic.

  13. Thiosemicarbazones as Aedes aegypti larvicidal.

    PubMed

    da Silva, João Bosco P; Navarro, Daniela Maria do A F; da Silva, Aluizio G; Santos, Geanne K N; Dutra, Kamilla A; Moreira, Diogo Rodrigo; Ramos, Mozart N; Espíndola, José Wanderlan P; de Oliveira, Ana Daura T; Brondani, Dalci José; Leite, Ana Cristina L; Hernandes, Marcelo Zaldini; Pereira, Valéria R A; da Rocha, Lucas F; de Castro, Maria Carolina A B; de Oliveira, Beatriz C; Lan, Que; Merz, Kenneth M

    2015-07-15

    A set of aryl- and phenoxymethyl-(thio)semicarbazones were synthetized, characterized and biologically evaluated against the larvae of Aedes aegypti (A. aegypti), the vector responsible for diseases like Dengue and Yellow Fever. (Q)SAR studies were useful for predicting the activities of the compounds not included to create the QSAR model as well as to predict the features of a new compound with improved activity. Docking studies corroborated experimental evidence of AeSCP-2 as a potential target able to explain the larvicidal properties of its compounds. The trend observed between the in silico Docking scores and the in vitro pLC50 (equals -log LC50, at molar concentration) data indicated that the highest larvicidal compounds, or the compounds with the highest values for pLC50, are usually those with the higher docking scores (i.e., greater in silico affinity for the AeSCP-2 target). Determination of cytotoxicity for these compounds in mammal cells demonstrated that the top larvicide compounds are non-toxic. PMID:26087027

  14. Persistent natural infection of a Culex tritaeniorhynchus cell line with a novel Culex tritaeniorhynchus rhabdovirus strain.

    PubMed

    Gillich, Nadine; Kuwata, Ryusei; Isawa, Haruhiko; Horie, Masayuki

    2015-09-01

    Culex tritaeniorhynchus rhabdovirus (CTRV) is a mosquito virus that establishes persistent infection without any obvious cell death. Therefore, occult infection by CTRV can be present in mosquito cell lines. In this study, it is shown that NIID-CTR cells, which were derived from Cx. tritaeniorhynchus, are persistently infected with a novel strain of CTRV. Complete genome sequencing of the infecting strain revealed that it is genetically similar but distinct from the previously isolated CTRV strain, excluding the possibility of contamination. These findings raise the importance of further CTRV studies, such as screening of CTRV in other mosquito cell lines.

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

    PubMed

    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.

  16. Curcuma Raktakanda is a Potential Larvicide for Mosquito Control.

    PubMed

    Latha, C; Ammini, J

    2000-01-01

    The leaves and tuber of Curcuma raktakanda were investigated as a mosquito larvicide against the early fourth instar larvae of four mosquito species, viz., Culex quinquefasciatus , Culex sitiens , Aedes aegypti and Anopheles stephensi . The petroleum ether extract of the leaves and tuber exhibited toxicity towards all the test species. The LC 90 values of leaf extract for Cx. quinquefasciatus , Cx. sitiens , Ae. aegypti and An. stephensi were 46.77, 27.45, 58.75 and 45.81 mg/l,respectively. The LC 90 values of crude extract of tuber were 44.88, 29.11, 48.08 and 37.49 mg/l for Cx. quinquefasciatus , Cx. sitiens , Ae. aegypti and An. stephensi , respectively. The crude extract of the tuber was fractionated using column chromatography and the activity of the fractions was studied against the test species. The LC 90 values of the biologically active fraction for Cx. quinquefasciatus , Cx. sitiens , Ae. aegypti and An. stephensi were 18.50, 12.82, 19.95 and 18.19 mg/l, respectively. The extracts were active after storage for one year.

  17. Sentinel site-enhanced near-real time surveillance documenting West Nile virus circulation in two Culex mosquito species indicating different transmission characteristics, Djibouti City, Djibouti.

    PubMed

    Faulde, Michael K; Spiesberger, Michael; Abbas, Babiker

    2012-08-01

    The Horn of Africa represents a region formerly known to be highly susceptible to mosquito-borne infectious diseases. In order to investigate whether autochthonous WNV transmission occurs in the Djibouti City area, in how far, and which of, the endemic Culex mosquito species are involved in WNV circulation activity,and whether sentinel site-enhanced near-real time surveillance (SSE-NRTS) may increase WNV detection sensitivity, mosquito vector monitoring was conducted from January 2010 to June 2012. Six monitoring locations, including two identified sentinel sites, considered most probable for potential anthroponotic and zoonotic virus circulation activity, have been continuously employed. Among the 20431 mosquitoes collected, 19069 (93.4%) were Cx. quinquefasciatus, and 1345 (6.6%) Cx. pipiens ssp. torridus. WNV lineage 2 circulation activity was detected between December 20th, 2010 and January 7th, 2011. Overall, 19 WNV RNA-positive mosquito pools were detected. Generally, urban environment-specific WNV-RNA circulation took place in Cx. pipiens ssp. torridus, whereas periurban and rural area-linked circulation was detected only in Cx. quinquefasciatus. Serological investigation data from 10 volunteers employed at the dislocated zoonotic WNV transmission sentinel site suggest that six persons (60%) had an acute, or recent, WNV infection. Results show that WNV should be considered endemic for Djibouti and sentinel site-enhanced near-real time surveillance is an elegant and highly effective epidemiological tool. In Djibouti, the endemicity level, public health impact and transmission modes of vector-borne diseases in concordance with locally optimized monitoring and control regimen deserve further investigation. PMID:23214223

  18. Host-feeding patterns of Culex pipiens and other potential mosquito vectors (Diptera: Culicidae) of West Nile virus (Flaviviridae) collected in Portugal.

    PubMed

    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.

  19. Spatial Stability of Adult Aedes aegypti Populations

    PubMed Central

    Barrera, Roberto

    2011-01-01

    Vector control programs could be more efficient by identifying the location of highly productive sites of Aedes aegypti. This study explored if the number of female adults of Ae. aegypti in BG-Sentinel traps was clustered and if their spatial distribution changed in time in two neighborhoods in San Juan, Puerto Rico. Traps were uniformly distributed across each neighborhood (130 m from each other), and samples were taken every 3 weeks. Global and local spatial autocorrelations were explored. Spatial stability existed if the rank order of trap captures was kept in time. There was lack of global autocorrelation in both neighborhoods, precluding their stratification for control purposes. Hot and cold spots were identified, revealing the highly focal nature of Ae. aegypti. There was significant spatial stability throughout the study in both locations. The consistency in trap productivity in time could be used to increase the effectiveness of vector and dengue control programs. PMID:22144449

  20. Trapping biases of Culex torrentium and Culex pipiens revealed by comparison of captures in CDC traps, ovitraps, and gravid traps.

    PubMed

    Hesson, Jenny C; Ignell, Rickard; Hill, Sharon R; Östman, Örjan; Lundström, Jan O

    2015-06-01

    We evaluate three trapping methods for their effectiveness at capturing Culex pipiens and Culex torrentium, both enzootic vectors of bird-associated viruses in Europe. The comparisons, performed in two regions in Sweden, were among CDC traps baited with carbon dioxide, gravid traps, and ovitraps baited with hay infusion. The proportions of the two Culex species in a catch differed between trap types, with CDC traps catching a lower proportion of Cx. torrentium than both gravid traps and ovitraps. Between gravid traps and ovitraps, there was no difference in the proportions of the two species. The results indicate that Cx. torrentium may go undetected or underestimated compared to Cx. pipiens when using carbon dioxide baited CDC traps. The new insight of trap bias presented here adds an important dimension to consider when investigating these vectors of bird-associated viruses in the field.

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

    PubMed

    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. PMID:16890387

  2. Neuropeptidomics of the mosquito Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Neuropeptidomic data were collected on the mosquito Ae. aegypti which is considered the most tractable mosquito species for physiological and endocrine studies. The data were solely obtained by direct mass spectrometric profiling, including tandem fragmentation, of selected tissues from single speci...

  3. Inhibition and Larvicidal Activity of Phenylpropanoids from Piper sarmentosum on Acetylcholinesterase against Mosquito Vectors and Their Binding Mode of Interaction

    PubMed Central

    Hematpoor, Arshia; Liew, Sook Yee; Chong, Wei Lim; Azirun, Mohd Sofian; Lee, Vannajan Sanghiran; Awang, Khalijah

    2016-01-01

    Aedes aegypti, Aedes albopictus and Culex quinquefasciatus are vectors of dengue fever and West Nile virus diseases. This study was conducted to determine the toxicity, mechanism of action and the binding interaction of three active phenylpropanoids from Piper sarmentosum (Piperaceae) toward late 3rd or early 4th larvae of above vectors. A bioassay guided-fractionation on the hexane extract from the roots of Piper sarmentosum led to the isolation and identification of three active phenylpropanoids; asaricin 1, isoasarone 2 and trans-asarone 3. The current study involved evaluation of the toxicity and acetylcholinesterase (AChE) inhibition of these compounds against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus larvae. Asaricin 1 and isoasarone 2 were highly potent against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus larvae causing up to 100% mortality at ≤ 15 μg/mL concentration. The ovicidal activity of asaricin 1, isoasarone 2 and trans-asarone 3 were evaluated through egg hatching. Asaricin 1 and isoasarone 2 showed potent ovicidal activity. Ovicidal activity for both compounds was up to 95% at 25μg/mL. Asaricin 1 and isoasarone 2 showed strong inhibition on acetylcholinesterase with relative IC50 values of 0.73 to 1.87 μg/mL respectively. These findings coupled with the high AChE inhibition may suggest that asaricin 1 and isoasarone 2 are neuron toxic compounds toward Aedes aegypti, Aedes albopictus and Culex quinquefasciatus. Further computational docking with Autodock Vina elaborates the possible interaction of asaricin 1 and isoasarone 2 with three possible binding sites of AChE which includes catalytic triads (CAS: S238, E367, H480), the peripheral sites (PAS: E72, W271) and anionic binding site (W83). The binding affinity of asaricin 1 and isoasarone 2 were relatively strong with asaricin 1 showed a higher binding affinity in the anionic pocket. PMID:27152416

  4. Effects of latitude and longitude on the population structure of Culex pipiens s.l., vectors of West Nile virus in North America.

    PubMed

    Edillo, Frances; Kiszewski, Anthony; Manjourides, Justin; Pagano, Marcello; Hutchinson, Michael; Kyle, Andrew; Arias, Jorge; Gaines, David; Lampman, Richard; Novak, Robert; Foppa, Ivo; Lubelcyzk, Charles; Smith, Robert; Moncayo, Abelardo; Spielman, Andrew

    2009-11-01

    We assessed the structure and latitudinal selection that might result in sensitivities to critical day-lengths that trigger diapause between Culex pipiens populations distributed along North-South and East-West axes in eastern North America. Strong population structure between Cx. p. pipiens and Cx. p. quinquefasciatus existed. Among Cx. p. pipiens, a 100-km increase in the latitudinal change resulted in an increased square root of F(ST) by 0.002. A 100-km increase in the longitudinal change caused an increased square root of F(ST) by 0.035. A lack of latitudinal influence on the structure between Cx. p. pipiens populations suggests a uniform signal using the 12 microsatellite markers, which might increase the risk of West Nile virus (WNV) transmission toward northern areas because of longer breeding season, extend host-seeking period, and larger population size. Northern Cx. p. pipiens may have undergone additional generations before diapause is triggered, magnifying population size when WNV amplification is peaking.

  5. CytA enables CryIV endotoxins of Bacillus thuringiensis to overcome high levels of CryIV resistance in the mosquito, Culex quinquefasciatus

    PubMed Central

    Wirth, M. C.; Georghiou, G. P.; Federici, B. A.

    1997-01-01

    Cry proteins produced by Bacillus thuringiensis are selective biodegradable insecticides used increasingly in bacterial insecticides and transgenic plants as alternatives to synthetic chemical insecticides. However, the potential for development of resistance and cross-resistance in target insect populations to Cry proteins used alone or in combination threatens the more widespread use of this novel pest control technology. Here we show that high levels of resistance to CryIV proteins in larvae of the mosquito, Culex quinquefasciatus, can be suppressed or reduced markedly by combining these proteins with sublethal quantities of CytA, a cytolytic endotoxin of B. thuringiensis. Resistance at the LC95 level of 127-fold for a combination of three CryIV toxins (CryIVA, B, and D), resulting from 60 generations of continuous selection, was completely suppressed by combining sporulated powders of CytA in a 1:3 ratio with sporulated powders of a CryIVA, CryIVB, and CryIVD strain. Combining the CytA strain with a CryIVA and CryIVB strain also completely suppressed mosquito resistance of 217-fold to the latter toxins at the LC95 level, whereas combination of CytA with CryIVD reduced resistance in a CryIVD-selected mosquito strain from greater than 1,000-fold to less than 8-fold. The CytA/CryIV model provides a potential molecular genetic strategy for engineering resistance management for Cry proteins directly into bacterial insecticides and transgenic plants. PMID:9380670

  6. Spatial and Temporal Habitat Segregation of Mosquitoes in Urban Florida

    PubMed Central

    Juliano, Steven A.

    2014-01-01

    Understanding mechanisms fostering coexistence between invasive and resident species is important in predicting ecological, economic, or health impacts of invasive species. The non-native mosquitoes Aedes aegypti and Culex quinquefasciatus have been resident in the southeastern United States for over a century. They coexist at some urban sites with the more recent invasive Aedes albopictus, which is usually superior in interspecific competition. We tested predictions of temporal and spatial habitat segregation that foster coexistence of these resident species with the superior invasive competitor. We measured spatial and temporal patterns of site occupancy and abundance for all three species among standard oviposition traps in metropolitan Tampa, Florida. Consistent with the condition-specific competition hypothesis, A. albopictus and A. aegypti abundances were greater and C. quinquefasciatus abundance was lower late (September) versus early (June) in the rainy season, and the proportional increase of A. albopictus abundance was greater than that of A. aegypti. These results are postulated to result from greater dry-season egg mortality and associated greater rainy-season competitive superiority of larvae of A. albopictus, followed by A. aegypti, and C. quinquefasciatus. Spatial partitioning among landscape variables was also evident among species, with A. albopictus more likely to oviposit across a range of open grass landscapes whereas A. aegypti were mostly restricted to cemeteries. Culex quinquefasciatus showed a shift in abundance from cemeteries early in the rainy season to developed areas characterized by built environments with large proportions of impervious surfaces late in the rainy season, where A. albopictus was not in its highest abundance. These results suggest that both temporal and spatial variation, and their interaction, may contribute to local coexistence between Aedes and Culex mosquito species in urban areas. PMID:24621592

  7. Population structure of the mosquito Aedes aegypti (Stegomyia aegypti) in Pakistan.

    PubMed

    Rasheed, S B; Boots, M; Frantz, A C; Butlin, R K

    2013-12-01

    Eleven microsatellite markers were used to determine the genetic population structure and spread of Aedes aegypti (Stegomyia aegypti) (Diptera: Culicidae) in Pakistan using mosquitoes collected from 13 different cities. There is a single genetic cluster of Ae. aegypti in Pakistan with a pattern of isolation by distance within the population. The low level of isolation by distance suggests the long-range passive dispersal of this mosquito, which may be facilitated by the tyre trade in Pakistan. A decrease in genetic diversity from south to north suggests a recent spread of this mosquito from Karachi. A strong negative correlation between genetic distance and the quality of road connections shows that populations in cities connected by better road networks are less differentiated, which suggests the human-aided passive dispersal of Ae. aegypti in Pakistan. Dispersal on a large spatial scale may facilitate the strategy of introducing transgenic Ae. aegypti or intracellular bacteria such as Wolbachia to control the spread of dengue disease in Pakistan, but it also emphasizes the need for simple measures to control container breeding sites.

  8. The use of morphometric wing characters to discriminate female Culex pipiens and Culex torrentium.

    PubMed

    Börstler, Jessica; Lühken, Renke; Rudolf, Martin; Steinke, Sonja; Melaun, Christian; Becker, Stefanie; Garms, Rolf; Krüger, Andreas

    2014-06-01

    The reliability of the length of wing radial vein r(2/3) as a character for the morphological discrimination of the two potential arbovirus vectors Culex pipiens s.s. and Cx. torrentium from Germany was reassessed, after this character had been neglected for more than 40 years. Additionally, multivariate morphometric analyses were applied to evaluate wing shape variation between both species. Although high-throughput molecular tools are now available to differentiate the two species, a simple, low-cost routine alternative may be useful in the absence of a molecular laboratory, such as under semi-field conditions. A thin-plate splines transformation confirmed that primarily the shrinkage of vein r(2/3) is responsible for the wing differences between the two species. In the bivariate analysis, the r(2/3)/r3 indices of Cx. pipiens s.s. and Cx. torrentium were 0.185 and 0.289, respectively, resulting in a correct classification of more than 91% of all tested specimens. Using the absolute length of vein r(2/3) alone still allowed for more than 90% accurate discrimination. Furthermore, classification accuracy of linear discriminant analysis exceeded 97%. PMID:24820574

  9. Effects of aqueous extract of deoiled neem (Azadirachta Indica A. juss) seed kernel and karanja (Pongamia Glabra vent) seed kernel against Culex quinquefasciatus.

    PubMed

    Sagar, S K; Sehgal, S S

    1996-12-01

    Aqueous extract obtained from deoiled neem and karanja seed kernels (ADNSD and ADKSK) were assessed for their toxic and growth regulating activities against Cx quinquefaciatus treated as first instar larvae. ADNSK at various concentrations was effective on the growth regulating mechanism, inducing prolonged larval stages. However, 100% larval mortality was observed, especially during the first and the second instars at all the tested concentrations. ADKSK caused 100% mortality in the fourth instar larvae and prepupae at the concentration of 100 ppm with no significant effect on the developmental period. The adults emerging from treated (50 ppm) larvae were smaller in size and malformed. We found ADNSK to be more effective than ADKSK. PMID:9057450

  10. Burchellin: study of bioactivity against Aedes aegypti

    PubMed Central

    2014-01-01

    Background The dengue mosquito Aedes aegypti Linnaeus, 1762 is a widespread insect pest of serious medical importance. Since no effective vaccine is available for treating dengue, the eradication or control of the main mosquito vector is regarded as essential. Since conventional insecticides have limited success, plants may be an alternative source of larvicidal agents, since they contain a rich source of bioactive chemicals. The aim of this study was to evaluate the larvicidal activity of the neolignan burchellin isolated from Ocotea cymbarum (Lauraceae), a plant from the Amazon region, against third instar larvae of A. aegypti. Methods Burchellin obtained from O. cymbarum was analyzed. The inhibitory activity against A. aegypti eggs and larvae and histological changes in the digestive system of treated L3 larvae were evaluated. In addition, nitric oxide synthase activity and nitric oxide levels were determined, and cytotoxicity bioassays performed. Results The data showed that burchellin interfered with the development cycle of the mosquito, where its strongest toxic effect was 100% mortality in larvae (L3) at concentrations ≥ 30 ppm. This compound did not show target cell toxicity in peritoneal macrophages from BALB/c mice, and proved to have molecular stability when dissolved in water. The L3 and L4 larvae treated with the compound showed cellular destruction and disorganization, cell spacing, and vacuolization of epithelial cells in small regions of the midgut. Conclusion The neolignan burchellin proved to be a strong candidate for a natural, safe and stable phytolarvicidal to be used in population control of A. aegypti. PMID:24713267

  11. Importance of ecology in Aedes aegypti control.

    PubMed

    Service, M W

    1992-12-01

    Aedes aegypti is one of the world's most widely distributed mosquitos and is of considerable medical importance as a vector of dengue and yellow fever. Not surprisingly therefore there has been more written on its biology than any other mosquito. The present paper summarizes ecological studies undertaken on this vector, including those on pre-adult mortalities, life-tables, adult dispersal and survival rates. In discussing surveillance techniques it is pointed out there are still no reliable methods for monitoring adult populations. The importance of the resting habits of adults and house construction in insecticidal control of Ae. aegypti is discussed. The question is, have ecological studies and population modeling resulted in any more understanding of the epidemiology of dengue, or helped formulate better control strategies? The answer seems to be not usually, possible because there have actually been relatively few good ecological studies on Ae. aegypti. Although mathematical modeling indicates that better control might be achieved if it were directed at the larvae, not adults, this has not usually been taken into consideration by those engaged in control. There is clearly need for greater collaboration between those practicing control, and ecologists and modelers.

  12. Spatial Variation in Host Feeding Patterns of Culex tarsalis and the Culex pipiens complex (Diptera: Culicidae) in California

    PubMed Central

    THIEMANN, T. C.; LEMENAGER, D. A.; KLUH, S.; CARROLL, B. D.; LOTHROP, H. D.; REISEN, W. K.

    2012-01-01

    West Nile virus (family Flaviviridae, genus Flavivirus, WNV) is now endemic in California across a variety of ecological regions that support a wide diversity of potential avian and mammalian host species. Because different avian hosts have varying competence for WNV, determining the blood-feeding patterns of Culex (Diptera: Culicidae) vectors is a key component in understanding the maintenance and amplification of the virus as well as tangential transmission to humans and horses. We investigated the blood-feeding patterns of Culex tarsalis Coquillett and members of the Culex pipiens L. complex from southern to northern California. Nearly 100 different host species were identified from 1,487 bloodmeals, by using the mitochondrial gene cytochrome c oxidase I (COI). Cx. tarsalis fed on a higher diversity of hosts and more frequently on nonhuman mammals than did the Cx. pipiens complex. Several WNV-competent host species, including house finch and house sparrow, were common bloodmeal sources for both vector species across several biomes and could account for WNV maintenance and amplification in these areas. Highly competent American crow, western scrub-jay and yellow-billed magpie also were fed upon often when available and are likely important as amplifying hosts for WNV in some areas. Neither species fed frequently on humans (Cx. pipiens complex [0.4%], Cx. tarsalis [0.2%]), but with high abundance, both species could serve as both enzootic and bridge vectors for WNV. PMID:22897051

  13. Productivity and population density estimates of the dengue vector mosquito Aedes aegypti (Stegomyia aegypti) in Australia.

    PubMed

    Williams, C R; Johnson, P H; Ball, T S; Ritchie, S A

    2013-09-01

    New mosquito control strategies centred on the modifying of populations require knowledge of existing population densities at release sites and an understanding of breeding site ecology. Using a quantitative pupal survey method, we investigated production of the dengue vector Aedes aegypti (L.) (Stegomyia aegypti) (Diptera: Culicidae) in Cairns, Queensland, Australia, and found that garden accoutrements represented the most common container type. Deliberately placed 'sentinel' containers were set at seven houses and sampled for pupae over 10 weeks during the wet season. Pupal production was approximately constant; tyres and buckets represented the most productive container types. Sentinel tyres produced the largest female mosquitoes, but were relatively rare in the field survey. We then used field-collected data to make estimates of per premises population density using three different approaches. Estimates of female Ae. aegypti abundance per premises made using the container-inhabiting mosquito simulation (CIMSiM) model [95% confidence interval (CI) 18.5-29.1 females] concorded reasonably well with estimates obtained using a standing crop calculation based on pupal collections (95% CI 8.8-22.5) and using BG-Sentinel traps and a sampling rate correction factor (95% CI 6.2-35.2). By first describing local Ae. aegypti productivity, we were able to compare three separate population density estimates which provided similar results. We anticipate that this will provide researchers and health officials with several tools with which to make estimates of population densities.

  14. [Diseases transmitted by mosquitoes and urbanization. Examples of urban vectors of dengue and filariasis].

    PubMed

    Rodhain, F

    1983-01-01

    Once located in time and place the beginning of urbanization process, the mechanisms of adaptation to urban ecosystem and of dissemination by human conveyances are studied for two domestic mosquitoes: Aedes aegypti and Culex pipiens fatigans (= quinque-fasciatus). Then epidemiological consequences are discussed. Ae. aegypti pullulation constitutes a potential risk of urban yellow fever outbreak and the main factor of dengue haemorrhagic fever appearance; the increase of C. p. fatigans populations involves a slow rise of bancroftian filariasis. Future prospects for these diseases are discussed with regards to data concerning recent evolution of their own epidemiological features.

  15. Evaluation of Tribulus terrestris Linn (Zygophyllaceae) acetone extract for larvicidal and repellence activity against mosquito vectors.

    PubMed

    Singh, S P; Raghavendra, K; Singh, R K; Mohanty, S S; Dash, A P

    2008-12-01

    Acetone extracts of leaves and seeds from the Tribulus terrestris (Zygophyllaceae) were tested against mature and immature different mosquito vectors under laboratory condition. The extract showed strong larvicidal, properties 100 per cent mortality in the 3rd-instar larvae was observed in the bioassays with An. culicifacies Giles species A, An. stephensi Liston, Culex quinquefasciatus Say and Aedes aegypti Linn, against 200 ppm of the leaf acetone extract and 100 ppm seed acetone extract. The LC50 values of leaf acetone extract estimated for 3rd-instars An. culicifacies species A, An. stephensi, Cx. quinquefasciatus and Ae. aegypti after 24 hour of exposure were 117, 124, 168 and 185 ppm respectively. The LC50 values of seed acetone extract estimated for 3rd-instars An. culicifacies species A, An. stephensi, Cx. quinquefasciatus and Ae. aegypti after 24 hour of exposure were 100, 72, 91 and 91 ppm respectively. It is confirmed from the LC50 values that the seed acetone extract of T. terrestris is more effective compared to leaf extracts. A significant (P<0.004) higher concentration of acetone extract leaf was required to kill equal number of larvae i.e. against acetone extract of seed. The seed acetone extract showed strong repellent activity against adults mosquitoes. Per cent protection obtained against Anopheles culicifacies species A 100% repellency in 1 h, 6 h; Anopheles stephensi 100% repellency in 0 h, 4 h, 6 h; and Culex quinquefasciatus 100% repellency in 0 h, 2 h, 4 h, at 10% concentration respectively. Against Deet- 2.5% An. culicifacies Giles species A has shown 100% repellency in 1 h, 2 h, 6 h, An. stephensi Liston 99% repellency in 4 h, and Culex quinquefasciatus Say has shown 100% repellency in 1 h, 2 h.

  16. Evaluation of Tribulus terrestris Linn (Zygophyllaceae) acetone extract for larvicidal and repellence activity against mosquito vectors.

    PubMed

    Singh, S P; Raghavendra, K; Singh, R K; Mohanty, S S; Dash, A P

    2008-12-01

    Acetone extracts of leaves and seeds from the Tribulus terrestris (Zygophyllaceae) were tested against mature and immature different mosquito vectors under laboratory condition. The extract showed strong larvicidal, properties 100 per cent mortality in the 3rd-instar larvae was observed in the bioassays with An. culicifacies Giles species A, An. stephensi Liston, Culex quinquefasciatus Say and Aedes aegypti Linn, against 200 ppm of the leaf acetone extract and 100 ppm seed acetone extract. The LC50 values of leaf acetone extract estimated for 3rd-instars An. culicifacies species A, An. stephensi, Cx. quinquefasciatus and Ae. aegypti after 24 hour of exposure were 117, 124, 168 and 185 ppm respectively. The LC50 values of seed acetone extract estimated for 3rd-instars An. culicifacies species A, An. stephensi, Cx. quinquefasciatus and Ae. aegypti after 24 hour of exposure were 100, 72, 91 and 91 ppm respectively. It is confirmed from the LC50 values that the seed acetone extract of T. terrestris is more effective compared to leaf extracts. A significant (P<0.004) higher concentration of acetone extract leaf was required to kill equal number of larvae i.e. against acetone extract of seed. The seed acetone extract showed strong repellent activity against adults mosquitoes. Per cent protection obtained against Anopheles culicifacies species A 100% repellency in 1 h, 6 h; Anopheles stephensi 100% repellency in 0 h, 4 h, 6 h; and Culex quinquefasciatus 100% repellency in 0 h, 2 h, 4 h, at 10% concentration respectively. Against Deet- 2.5% An. culicifacies Giles species A has shown 100% repellency in 1 h, 2 h, 6 h, An. stephensi Liston 99% repellency in 4 h, and Culex quinquefasciatus Say has shown 100% repellency in 1 h, 2 h. PMID:19579717

  17. Larvicidal efficacies and chemical composition of essential oils of Pinus sylvestris and Syzygium aromaticum against mosquitoes

    PubMed Central

    Fayemiwo, Kehinde Adenike; Adeleke, Monsuru Adebayo; Okoro, Ovie Princewill; Awojide, Shola Hezekiah; Awoniyi, Ilias Olufemi

    2014-01-01

    Objective To assess the chemical composition and mosquito larvicidal potentials of essential oils of locally sourced Pinus sylvestris (P. sylvestris) and Syzygium aromaticum (S. aromaticum) against Aedes aegypti (A. aegypti) and Culex quinquefasciatus (C. quinquefasciatus). Method The chemical composition of the essential oils of both plants was determined using GC-MS while the larvicidal bioassay was carried out using different concentrations of the oils against the larvae of A. aegypti and C. quinquefasciatus in accordance with the standard protocol. Results The results as determined by GC-MS showed that oil of S. aromaticum has eugenol (80.5%) as its principal constituent while P. sylvestris has 3-Cyclohexene-1-methanol, .alpha., .alpha.4-trimethyl (27.1%) as its dominant constituent. Both oils achieved over 85% larval mortality within 24 h. The larvae of A. aegypti were more susceptible to the oils [LC50 (S. aromaticum)=92.56 mg/L, LC50(P. sylvestris)=100.39 mg/L] than C. quinquefasciatus [LC50(S. aromaticum)=124.42 mg/L; LC50(P. sylvestris)=128.00 mg/L]. S. aromaticum oil was more toxic to the mosquito larvae than oil of P. sylvestris but the difference in lethal concentrations was insignificant (P>0.05). Conclusion The results justify the larvicidal potentials of both essential oils and the need to incorporate them in vector management and control. PMID:24144127

  18. Insecticide susceptibility in mosquitoes (Diptera: Culicidae) from French Polynesia.

    PubMed

    Failloux, A B; Ung, A; Raymond, M; Pasteur, N

    1994-09-01

    Susceptibility to six organophosphate (OP), two pyrethroid (PY), and one carbamate (C) insecticides was investigated in Culex pipiens quinquefasciatus Say, Aedes aegypti (L.), and Aedes polynesiensis Marks larvae from the island of Tahiti. Cx. p. quinquefasciatus and Ae. aegypti were compared with susceptible reference strains treated simultaneously. A low, but significant, resistance to bromophos (4.6x), chlorpyrifos (5.7x), fenthion (2.4x), fenitrothion (5.0x), temephos (4.3x) and permethrin (2.1x) was found in Cx. p. quinquefasciatus, and to malathion (1.5x), temephos (2.3x), permethrin (1.8x) and propoxur (1.7x) in Ae. aegypti. Cx. p. quinquefasciatus was shown to possess over-produced esterases A2 and B2, which are known to be involved in resistance to OPs in other countries. Ae. polynesiensis was less resistant than the Ae. aegypti reference strain to all insecticides except temephos (1.8x) and permethrin (6.7x). To determine whether Ae. polynesiensis had developed resistance to these insecticides in Tahiti, a geographical survey covering 12 islands of the Society, Tuamotu, Tubuai, Marquesas, and Gambier archipelagoes was undertaken with three insecticides (temephos, deltamethrin, and permethrin). Two- to threefold variations in LC50S were observed among collections. Results are discussed in relationship to the level of insecticide exposure on the different islands. PMID:7966164

  19. Insecticide susceptibility in mosquitoes (Diptera: Culicidae) from French Polynesia.

    PubMed

    Failloux, A B; Ung, A; Raymond, M; Pasteur, N

    1994-09-01

    Susceptibility to six organophosphate (OP), two pyrethroid (PY), and one carbamate (C) insecticides was investigated in Culex pipiens quinquefasciatus Say, Aedes aegypti (L.), and Aedes polynesiensis Marks larvae from the island of Tahiti. Cx. p. quinquefasciatus and Ae. aegypti were compared with susceptible reference strains treated simultaneously. A low, but significant, resistance to bromophos (4.6x), chlorpyrifos (5.7x), fenthion (2.4x), fenitrothion (5.0x), temephos (4.3x) and permethrin (2.1x) was found in Cx. p. quinquefasciatus, and to malathion (1.5x), temephos (2.3x), permethrin (1.8x) and propoxur (1.7x) in Ae. aegypti. Cx. p. quinquefasciatus was shown to possess over-produced esterases A2 and B2, which are known to be involved in resistance to OPs in other countries. Ae. polynesiensis was less resistant than the Ae. aegypti reference strain to all insecticides except temephos (1.8x) and permethrin (6.7x). To determine whether Ae. polynesiensis had developed resistance to these insecticides in Tahiti, a geographical survey covering 12 islands of the Society, Tuamotu, Tubuai, Marquesas, and Gambier archipelagoes was undertaken with three insecticides (temephos, deltamethrin, and permethrin). Two- to threefold variations in LC50S were observed among collections. Results are discussed in relationship to the level of insecticide exposure on the different islands.

  20. Guppies as predators of common mosquito larvae in Malaysia.

    PubMed

    Saleeza, S N R; Norma-Rashid, Y; Sofian-Azirun, M

    2014-03-01

    Observation on predation activities of guppies (Poecilia reticulata) on the larvae of three species of mosquito, namely Aedes albopictus, Aedes aegypti, and Culex quinquefasciatus was carried out under laboratory conditions. Male and female guppies were used as predators for predation experiments on the 4th instars of mosquito larvae. The daily feeding rates comparing male and female guppies on mosquito larvae were different; the female guppies consumed more mosquito larvae than male guppies did. The daily feeding rates of female guppies were 121.3 for Ae. aegypti, 105.6 for Ae. albopictus, and 72.3 for Cx. quinquefasciatus. The daily feeding rates of male guppies were 98.6 for Ae. aegypti, 73.6 for Ae. albopictus, and 47.6 for Cx. quinquefasciatus. In terms of prey preference, there was greater preference towards mosquito larvae of Ae. aegypti, followed by Ae. albopictus, and the least preferred was Cx. quinquefasciatus. Male and female guppies consumed more mosquito larvae during lights on (day time) compared with lights off (night time). The water volume, prey species, number of fish predators available, prey densities, and prey's sex also influenced the predation activities. PMID:24968669

  1. Mosquito blood-meal analysis for avian malaria study in wild bird communities: laboratory verification and application to Culex sasai (Diptera: Culicidae) collected in Tokyo, Japan.

    PubMed

    Kim, Kyeong Soon; Tsuda, Yoshio; Sasaki, Toshinori; Kobayashi, Mutsuo; Hirota, Yoshikazu

    2009-10-01

    We conducted laboratory experiments to verify molecular techniques of avian malaria parasite detection distinguishing between an infected mosquito (oocysts on midgut wall) and infective mosquito (sporozoites in salivary glands) in parallel with blood-meal identification from individual blood-fed mosquitoes prior to application to field survey for avian malaria. Domestic fowl infected with Plasmodium gallinaceum was exposed to a vector and non-vector mosquito species, Aedes aegypti and Culex pipiens pallens, respectively, to compare the time course of polymerase chain reaction (PCR) detection for parasite between competent and refractory mosquitoes. DNA of the domestic fowl was detectable for at least 3 days after blood feeding. The PCR-based detection of P. gallinaceum from the abdomen and thorax of A. aegypti corresponded to the microscopic observation of oocysts and sporozoites. Therefore, this PCR-based method was considered useful as one of the criteria to assess developmental stages of Plasmodium spp. in mosquito species collected in the field. We applied the same PCR-based method to 21 blood-fed C. sasai mosquitoes collected in Rinshi-no-mori Park in urban Tokyo, Japan. Of 15 blood meals of C. sasai successfully identified, 86.7% were avian-derived, 13.3% were bovine-derived. Plasmodium DNA was amplified from the abdomen of three C. sasai specimens having an avian blood meal from the Great Tit (Parus major), Pale Thrush (Turdus pallidus), and Jungle Crow (Corvus macrorhynchos). This is the first field study on host-feeding habits of C. sasai in relation to the potential role as a vector for avian malaria parasites transmitted in the Japanese wild bird community.

  2. Aedes aegypti resistance to temephos in Argentina.

    PubMed

    Seccacini, Emilia; Lucia, Alejandro; Zerba, Eduardo; Licastro, Susana; Masuh, Hector

    2008-12-01

    Monitoring of resistance of Aedes aegypti to temephos was implemented in the provinces of Formosa and Misiones, Argentina, as a response to the need to improve the vigilance for the dengue vector in areas of high risk of dengue. Eggs collected in each locality were reared, and susceptibility to temephos was assayed using larval bioassays. A weak decrease in susceptibility of larvae to temephos was observed in Clorinda and Puerto Iguazú, indicating an incipient resistance with a resistance ratio of 3. No control failures have been observed yet, and this program should allow the early detection of a real problem in our country.

  3. HISTOCHEMICAL EFFECTS OF SOME BIOLOGICAL AGENTS ON CULEX PIPIENS LARVAE.

    PubMed

    El Sobky, Mona M; Ismail, Howaida I H; Assar, Abada A

    2016-04-01

    The histochemical effects of the lethal concentration that kills 50% of larvae (LC50) of three biological agents, abamectin, Bacillus thuringiensis and spinosad on the carbohydrates (polysaccharides), proteins, nucleic acids and lipids content of the midgut and fat bodies of Culex pipiens 2nd instar larvae were studied. The results showed that the three tested compounds reduced the carbohydrates (polysaccharides), proteins, RNA synthesis and lipids content after 72 hours of treatment where abamectin was the most effective followed by Bacillus thuringiensis then spinosad. PMID:27363043

  4. The dengue vector Aedes aegypti: what comes next.

    PubMed

    Jansen, Cassie C; Beebe, Nigel W

    2010-04-01

    Aedes aegypti is the urban vector of dengue viruses worldwide. While climate influences the geographical distribution of this mosquito species, other factors also determine the suitability of the physical environment. Importantly, the close association of A. aegypti with humans and the domestic environment allows this species to persist in regions that may otherwise be unsuitable based on climatic factors alone. We highlight the need to incorporate the impact of the urban environment in attempts to model the potential distribution of A. aegypti and we briefly discuss the potential for future technology to aid management and control of this widespread vector species.

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

    PubMed

    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.

  6. Aedes aegypti D7 Saliva Protein Inhibits Dengue Virus Infection

    PubMed Central

    Conway, Michael J.; Londono-Renteria, Berlin; Troupin, Andrea; Watson, Alan M.; Klimstra, William B.; Fikrig, Erol; Colpitts, Tonya M.

    2016-01-01

    Aedes aegypti is the primary vector of several medically relevant arboviruses including dengue virus (DENV) types 1–4. Ae. aegypti transmits DENV by inoculating virus-infected saliva into host skin during probing and feeding. Ae. aegypti saliva contains over one hundred unique proteins and these proteins have diverse functions, including facilitating blood feeding. Previously, we showed that Ae. aegypti salivary gland extracts (SGEs) enhanced dissemination of DENV to draining lymph nodes. In contrast, HPLC-fractionation revealed that some SGE components inhibited infection. Here, we show that D7 proteins are enriched in HPLC fractions that are inhibitory to DENV infection, and that recombinant D7 protein can inhibit DENV infection in vitro and in vivo. Further, binding assays indicate that D7 protein can directly interact with DENV virions and recombinant DENV envelope protein. These data reveal a novel role for D7 proteins, which inhibits arbovirus transmission to vertebrates through a direct interaction with virions. PMID:27632170

  7. Microinjection of A. aegypti embryos to obtain transgenic mosquitoes.

    PubMed

    Jasinskiene, Nijole; Juhn, Jennifer; James, Anthony A

    2007-01-01

    In this video, Nijole Jasinskiene demonstrates the methodology employed to generate transgenic Aedes aegypti mosquitoes, which are vectors for dengue fever. The techniques for correctly preparing microinjection needles, desiccating embryos, and performing microinjection are demonstrated.

  8. Aedes aegypti D7 Saliva Protein Inhibits Dengue Virus Infection.

    PubMed

    Conway, Michael J; Londono-Renteria, Berlin; Troupin, Andrea; Watson, Alan M; Klimstra, William B; Fikrig, Erol; Colpitts, Tonya M

    2016-09-01

    Aedes aegypti is the primary vector of several medically relevant arboviruses including dengue virus (DENV) types 1-4. Ae. aegypti transmits DENV by inoculating virus-infected saliva into host skin during probing and feeding. Ae. aegypti saliva contains over one hundred unique proteins and these proteins have diverse functions, including facilitating blood feeding. Previously, we showed that Ae. aegypti salivary gland extracts (SGEs) enhanced dissemination of DENV to draining lymph nodes. In contrast, HPLC-fractionation revealed that some SGE components inhibited infection. Here, we show that D7 proteins are enriched in HPLC fractions that are inhibitory to DENV infection, and that recombinant D7 protein can inhibit DENV infection in vitro and in vivo. Further, binding assays indicate that D7 protein can directly interact with DENV virions and recombinant DENV envelope protein. These data reveal a novel role for D7 proteins, which inhibits arbovirus transmission to vertebrates through a direct interaction with virions. PMID:27632170

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

    PubMed

    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.

  10. Analysis of Mosquito-Borne Flavivirus Superinfection in Culex tritaeniorhynchus (Diptera: Culicidae) Cells Persistently Infected with Culex Flavivirus (Flaviviridae).

    PubMed

    Kuwata, Ryusei; Isawa, Haruhiko; Hoshino, Keita; Sasaki, Toshinori; Kobayashi, Mutsuo; Maeda, Ken; Sawabe, Kyoko

    2015-03-01

    Superinfection exclusion is generally defined as a phenomenon in which a pre-existing viral infection prevents a secondary viral infection; this has also been observed in infections with mosquito-borne viruses. In this study, we examined the superinfection exclusion of the vertebrate-infecting flaviviruses, Japanese encephalitis virus (JEV) and dengue virus (DENV), by stable and persistent infection with an insect-specific flavivirus, Culex flavivirus (CxFV), in a Culex tritaeniorhynchus Giles cell line (CTR cells). Our experimental system was designed based on the premise that wild Cx. tritaeniorhynchus mosquitoes naturally infected with CxFV are superinfected with JEV by feeding on JEV-infected animals. As a result, we found no evidence of the superinfection exclusion of both JEV and DENV by pre-existing CxFV infection at the cellular level. However, JEV superinfection induced severe cytopathic effects on persistently CxFV-infected CTR cells. These observations imply the possibility that JEV superinfection in CxFV-infected Cx. tritaeniorhynchus mosquitoes has an adverse effect on their fitness.

  11. Mosquito larvicidal properties of essential oil of an indigenous plant, Ipomoea cairica Linn.

    PubMed

    Thomas, Thekkevilayil George; Rao, Sunder; Lal, Shiv

    2004-08-01

    Laboratory bioassay of the essential oil extracted from an indigenous plant, Ipomoea cairica, commonly known as 'Railway creeper', was carried out against the larvae of four vector species of mosquitoes in order to evaluate its mosquito larvicidal effect. Bioassay test revealed that the essential oil of the plant possess remarkable larvicidal properties as it could induce 100% mortality in the larvae of Culex tritaeniorhynchus (100 ppm), Aedes aegypti (120 ppm), Anopheles stephensi (120 ppm), and Culex quinquefasciatus (170 ppm) mosquitoes at concentrations rangeing from 100 to 170 ppm. The LC(50) and LC(90) values estimated for Cx. tritaeniorhynchus, Ae. aegypti, An. stephensi, and Cx. quinquefasciatus were 14.8 and 78.3, 22.3 and 92.7, 14.9 and 109.9, and 58.9 and 161.6 ppm, respectively. The essential oil was found to be most highly toxic to the larvae of Cx. tritaeniorhynchus followed by Ae. aegypti, An. stephensi, and Cx. quinquefasciatus mosquitoes. PMID:15329451

  12. Morphological and genetic variability within Aedes aegypti in Niakhar, Senegal.

    PubMed

    Paupy, Christophe; Brengues, Cécile; Ndiath, Ousmane; Toty, Céline; Hervé, Jean-Pierre; Simard, Frédéric

    2010-05-01

    Aedes aegypti (Linné, 1762) is a major vector of arboviruses such as Yellow Fever, Dengue and Chikungunya. In Africa, where the species exhibits major variations in morphology, ecology, behavior and vector competence, two subspecies have been described: a light form, named Ae. aegypti aegypti (Aaa) with highly domestic and anthropophilic habits and a cosmotropical distribution; and a dark form, referred to as Ae. aegypti formosus (Aaf), which is endemic to Africa and thrives in sylvan environments. In East Africa, both forms were described to occur in sympatry whereas only Aaf was reported from Central/West Africa. However, recent findings suggest Aaa was also common in Senegal. Here, we report on a longitudinal survey of morphological and genetic variability of Ae. aegypti sampled in the rural environment of Niakhar, Senegal. In agreement with recent findings, most of specimens we analyzed were classified as Aaa suggesting typical Aaf was scarce in the studied area. Among Aaa, significant temporal variations in abdominal pale scales pattern were detected. Depending on the season and the nature of larval breeding places, the specimens (particularly females) tend to segregate in two main morphological groups. Microsatellite-based estimates of genetic differentiation did not provide any clear evidence that the two groups were genetically distinct. Overall, these results improve our understanding of the diversity of Ae. aegypti in West Africa, where data are crucially lacking.

  13. Lessons of Aedes aegypti control in Thailand.

    PubMed

    Gratz, N G

    1993-01-01

    The incidence of dengue haemorrhagic fever (DHF) in Thailand has increased cyclically since the first recognized outbreak in 1958. Without an effective vaccine against dengue, and considering the clinical difficulty of treating DHF cases, vector control is needed to prevent dengue transmission. Since the establishment of the WHO Aedes Research Unit in 1964, continued since 1973 as the WHO Collaborating Centre at the Department of Medical Research in Bangkok, much operational research has been carried out in Thailand on the bionomics and control of dengue vectors: Aedes aegypti and Ae. albopictus. This review shows that, as in most other countries, dengue vector control programmes in Thailand make little use of the procedures arising from research, nor have they reduced the upward trend of dengue or prevented DHF outbreaks. Implications of the reluctance to use results of operational research on vector control are considered and remedial suggestions made.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Insights into host-finding by Culex mosquitoes: New tools for surveillance?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Culex mosquitoes are important vectors of pathogens and parasites causing diseases such as West Nile virus, St. Louis encephalitis, Japanese encephalitis, Venezuelan equine encephalitis and bancroftian filariasis. Surveillance of these species is based on traps using conventional mosquito attractan...

  16. [Oral receptivity of Aedes aegypti formosus from Franceville (Gabon, central Africa) for type 2 dengue virus].

    PubMed

    Vazeille-Falcoz, M; Failloux, A B; Mousson, L; Elissa, N; Rodhain, F

    1999-12-01

    Dengue is widely distributed in the tropics but epidemic activity was rarely reported in Africa before the 1980's. In the past 15 years, increased epidemic dengue fever has been reported both in East and West Africa, raising concern about the ability of local populations of Aedes aegypti to transmit dengue viruses. Ae. aegypti is present in two forms in Africa: Ae. aegypti aegypti and Ae. aegypti formosus. This latter form, much darker, was not originally a local species but is now colonizing artificial breeding sites within cities. We have been able to demonstrate the oral susceptibility for dengue type 2 virus of Ae. aegypti formosus collected in Franceville, Gabon (Central Africa). However, these mosquitoes sampled exhibited lower infection rates than those of a control colony of Ae. aegypti aegypti originating from French Polynesia.

  17. Dieldrin resistance in Culex pipiens fatigans in Malaya.

    PubMed

    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.

  18. The pathogenesis of Japanese encephalitis virus in Culex tritaeniorhynchus mosquitoes.

    PubMed

    Leake, C J; Johnson, R T

    1987-01-01

    Culex tritaeniorhynchus were inoculated intrathoracically with mosquito and human strains of Japanese encephalitis virus and maintained at 26 degrees C or 32 degrees C. Virus titration and localization of viral antigen by avidin-biotin immunoperoxidase staining were done at intervals up to 21 days. Marked differences were noted in the tempo of organ involvement at the 2 temperatures; at both there was initial infection of fat body cells followed by selective infection of the central nervous system (CNS), with consistent infection of cells of the compound eye, patchy involvement of cephalic, thoracic and abdominal ganglia and no infection of Johnston's organ. CNS infection was always present 4 days after infection, when salivary gland involvement was first seen at 32 degrees C; at 26 degrees C CNS infection preceded salivary gland infection by 2 weeks. Late involvement of gut cells, pericardial cells and oviducts was also found, with no involvement of muscle.

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

    SciTech Connect

    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.

  20. Wing geometry of Culex coronator (Diptera: Culicidae) from South and Southeast Brazil

    PubMed Central

    2014-01-01

    Background The Coronator Group encompasses Culex coronator Dyar & Knab, Culex camposi Dyar, Culex covagarciai Forattini, Culex ousqua Dyar, Culex usquatissimus Dyar, Culex usquatus Dyar and Culex yojoae Strickman. Culex coronator has the largest geographic distribution, occurring in North, Central and South America. Moreover, it is a potential vector-borne mosquito species because females have been found naturally infected with several arboviruses, i.e., Saint Louis Encephalitis Virus, Venezuelan Equine Encephalitis Virus and West Nile Virus. Considering the epidemiological importance of Cx. coronator, we investigated the wing shape diversity of Cx. coronator from South and Southeast Brazil, a method to preliminarily estimate population diversity. Methods Field-collected immature stages of seven populations from a large geographical area in Brazil were maintained in the laboratory to obtain both females and males linked with pupal and/or larval exuviae. For each individual female, 18 landmarks of left wings were marked and digitalized. After Procrustes superimposition, discriminant analysis of shape was employed to quantify wing shape variation among populations. The isometric estimator centroid size was calculated to assess the overall wing size and allometry. Results Wing shape was polymorphic among populations of Cx. coronator. However, dissimilarities among populations were higher than those observed within each population, suggesting populational differentiation in Cx. coronator. Morphological distances between populations were not correlated to geographical distances, indicating that other factors may act on wing shape and thus, determining microevolutionary patterns in Cx. coronator. Despite the population differentiation, intrapopulational wing shape variability was equivalent among all seven populations. Conclusion The wing variability found in Cx. coronator populations brings to light a new biological problem to be investigated: the population genetics of

  1. Mayaro virus and dengue virus 1 and 4 natural infection in culicids from Cuiabá, state of Mato Grosso, Brazil

    PubMed Central

    Serra, Otacília Pereira; Cardoso, Belgath Fernandes; Ribeiro, Ana Lúcia Maria; dos Santos, Fábio Alexandre Leal; Slhessarenko, Renata Dezengrini

    2016-01-01

    This study aimed to verify the diversity of Culicidae species and their frequency of infection with flaviviruses and alphaviruses in Cuiabá, state of Mato Grosso, Brazil. Mosquitoes were captured with Nasci aspirators and hand net in 200 census tracts, identified alive at species level and pooled in one-20 (11,090 mosquitoes, 14 species). Female pools (n = 610) were subjected to multiplex seminested-reverse transcription-polymerase chain reaction (RT-PCR) for 11 flavivirus and five alphavirus. Positive pools were tested by single RT-PCR followed by nucleotide sequencing, by RT-PCR for E1 gene [Mayaro virus (MAYV)] and by inoculation in Vero cells (MAYV) or C6/36 cells (flaviviruses). One/171 Aedes aegypti was positive for dengue virus (DENV)-1, 12/403 Culex quinquefasciatus, and four/171Ae. aegypti for MAYV, which was isolated from two pools containing two nonengorged females of Ae. aegypti and two ofCx. quinquefasciatus. DENV-4 was detected in 58/171 pools of Ae. aegytpi, 105/403 Cx. quinquefasciatus, two/five Psorophora sp., two/11 Psorophora varipes/Psorophora albigenu, one/one Sabethes chloropterus, two/five Culex bidens/Culex interfor, and one/one Aedes sp. DENV-4 was isolated from two pools containing three and 16 nonengorged Cx. quinquefasciatus females. Phylogenetic analysis revealed MAYV belongs to genotype L, clustering with human samples of the virus previously identified in the city. Cuiabá has biodiversity and ecosystem favourable for vector proliferation, representing a risk for arbovirus outbreaks. PMID:26784852

  2. Is the extract from the plant catmint (Nepeta cataria) repellent to mosquitoes in Australia?

    PubMed

    Webb, Cameron E; Russell, Richard C

    2007-09-01

    The repellency of Nepeta cataria (catmint or catnip) was tested against Aedes aegypti, Ae. vigilax, Culex annulirostris, and Cx. quinquefasciatus, and compared with a blend of natural plant extracts and N,N-diethyl-3-methylbenzamide (deet) on human skin. The catmint and natural plant extract blend did not provide the same level of protection from biting mosquitoes as deet. There were significant differences in the level of protection provided by catmint to the 4 species of mosquito, with mean protection times ranging from 0 min for Ae. aegypti up to 240 +/- 60 min for Cx. quinquefasciatus. Significant differences in the mean landing rates of the 4 mosquito species on untreated forearms highlighted the difficulties in comparing laboratory tests of repellents between species.

  3. Mosquito larvicidal activity of isolated compounds from the rhizome of Zingiber officinale.

    PubMed

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

    2008-08-01

    The larvicidal activity of a petroleum ether extract of Zingiber officinale Roscoe (Zingiberaceae) was evaluated against Aedes aegypti L. and Culex quinquefasciatus Say (Diptera). Bioassay-guided fractionation led to the isolation of 4-gingerol (1), (6)-dehydrogingerdione (2) and (6)-dihydrogingerdione (3); the latter has not previously been reported from Z. officinale. The structures were established from infrared (IR), ultraviolet (UV), (1)H-nuclear magnetic resonance (NMR), (13)C-NMR and mass spectral data. Following a 24 h exposure, compounds 1-3 exhibited larvicidal activities against fourth instar larvae of A. aegypti (LC(50) 4.25, 9.80, 18.20 ppm) and C. quinquefasciatus (LC50 5.52, 7.66, 27.24 ppm), respectively. The results show that the most effective compound was 4-gingerol. PMID:18618523

  4. Dengue-2 virus carrying capacity of Thai Aedes aegypti strains with different susceptibility to deltamethrin.

    PubMed

    Phanpoowong, Theerawit; Lek-Uthai, Usa; Thongrungkiat, Supatra; Komalamisra, Narumon; Srisawat, Raweewan; Russell, Bruce; Renia, Laurent

    2012-05-01

    Deltamethrin-resistant Aedes aegypti currently threatens the effectiveness of dengue hemorrhagic fever control operations in Thailand. Although a previous study has suggested that insecticide resistance may increase Ae. aegypti susceptibility to dengue-2 virus infection, our experimental data showed no significant association between laboratory-induced deltamethrin-resistance in a Thai Ae. aegypti isolate and its susceptibility to dengue -2 infection.

  5. [Detection of Aedes (Stegomyia) Aegypti L. mosquitoes in Sochi city].

    PubMed

    Riabova, T E; Iunicheva, Iu V; Markovich, N Ia; Ganushkina, L A; Orabeĭ, V G; Sergiev, V P

    2005-01-01

    Few Aedes aegypti females were found when collecting the mosquitoes attacking human beings in the Central District of Sochi in August to September 2001-2004. Ae. aegypti, a vector of dangerous causative agents of diseases, such as yellow and Aden fevers, appeared on the Black Sea coast of the Caucasus is recorded after its long absence. By taking into account the potential epidemic value of Ae. aegypti, it is necessary to make a monitoring in the cities, towns, and settlements to establish the spread, number, and the breading sites of mosquitoes in the given area and to prevent their mass reproduction. The effectiveness of Ae. albopictus as a vector of Aden fever has been established in different regions of the world. Entomological surveys for Ae. albopictus should be made in the areas of Russia where Ae. aegypti mosquitoes were distributed early in the past century, particularly in the southern port towns and settlements of Russia. Ae. albopictus is potentially able to spread to the north further than is Ae. aegypti.

  6. Potential Effects of Climate Change on Ecological Interaction Outcomes Between Two Disease-Vector Mosquitoes: A Mesocosm Experimental Study.

    PubMed

    Leonel, B F; Koroiva, R; Hamada, N; Ferreira-Keppler, R L; Roque, F O

    2015-09-01

    The objective of this study was to experimentally assess the effects of different climate change scenarios on the outcomes of interactions between Aedes aegypti (L.) and Culex quinquefasciatus (Say) (Diptera: Culicidae) larvae. The experimental design maintained a constant density of specimens while the proportion of the species in different experimental climate change scenarios varied. Our results indicate that survival of the two species was not affected, but larval development and pupation times decreased under elevated atmospheric CO(2) concentration and high air temperature. In climate change scenarios with both species together, the survival of Ae. aegypti increased and its larval development time decreased with increasing density of Cx. quinquefasciatus. This may be attributed to the effects of intraspecific competition being more significant than interspecific competition in Ae. aegypti. Our study also reveals that climatic changes may affect the patterns of interactions between Cx. quinquefasciatus and Ae. aegypti. Alterations in climatic conditions changed the response of context-dependent competition, indicating the importance of studies on how ecological interactions will be affected by projected future climatic change.

  7. Potential Effects of Climate Change on Ecological Interaction Outcomes Between Two Disease-Vector Mosquitoes: A Mesocosm Experimental Study.

    PubMed

    Leonel, B F; Koroiva, R; Hamada, N; Ferreira-Keppler, R L; Roque, F O

    2015-09-01

    The objective of this study was to experimentally assess the effects of different climate change scenarios on the outcomes of interactions between Aedes aegypti (L.) and Culex quinquefasciatus (Say) (Diptera: Culicidae) larvae. The experimental design maintained a constant density of specimens while the proportion of the species in different experimental climate change scenarios varied. Our results indicate that survival of the two species was not affected, but larval development and pupation times decreased under elevated atmospheric CO(2) concentration and high air temperature. In climate change scenarios with both species together, the survival of Ae. aegypti increased and its larval development time decreased with increasing density of Cx. quinquefasciatus. This may be attributed to the effects of intraspecific competition being more significant than interspecific competition in Ae. aegypti. Our study also reveals that climatic changes may affect the patterns of interactions between Cx. quinquefasciatus and Ae. aegypti. Alterations in climatic conditions changed the response of context-dependent competition, indicating the importance of studies on how ecological interactions will be affected by projected future climatic change. PMID:26336208

  8. Schools as Potential Risk Sites for Vector-Borne Disease Transmission: Mosquito Vectors in Rural Schools in Two Municipalities in Colombia.

    PubMed

    Olano, Víctor Alberto; Matiz, María Inés; Lenhart, Audrey; Cabezas, Laura; Vargas, Sandra Lucía; Jaramillo, Juan Felipe; Sarmiento, Diana; Alexander, Neal; Stenström, Thor Axel; Overgaard, Hans J

    2015-09-01

    Dengue and other vector-borne diseases are of great public health importance in Colombia. Vector surveillance and control activities are often focused at the household level. Little is known about the importance of nonhousehold sites, including schools, in maintaining vector-borne disease transmission. The objectives of this paper were to determine the mosquito species composition in rural schools in 2 municipalities in Colombia and to assess the potential risk of vector-borne disease transmission in school settings. Entomological surveys were carried out in rural schools during the dry and rainy seasons of 2011. A total of 12 mosquito species were found: Aedes aegypti, Anopheles pseudopunctipennis, Culex coronator, Cx. quinquefasciatus, and Limatus durhamii in both immature and adult forms; Ae. fluviatilis, Cx. nigripalpus, Cx. corniger, and Psorophora ferox in immature forms only; and Ae. angustivittatus, Haemagogus equinus, and Trichoprosopon lampropus in adult forms only. The most common mosquito species was Cx. quinquefasciatus. Classrooms contained the greatest abundance of adult female Ae. aegypti and Cx. quinquefasciatus. The most common Ae. aegypti breeding sites were containers classified as "others" (e.g., cans), followed by containers used for water storage. A high level of Ae. aegypti infestation was found during the wet season. Our results suggest that rural schools are potentially important foci for the transmission of dengue and other mosquito-borne diseases. We propose that public health programs should be implemented in rural schools to prevent vector-borne diseases. PMID:26375902

  9. Schools as Potential Risk Sites for Vector-Borne Disease Transmission: Mosquito Vectors in Rural Schools in Two Municipalities in Colombia.

    PubMed

    Olano, Víctor Alberto; Matiz, María Inés; Lenhart, Audrey; Cabezas, Laura; Vargas, Sandra Lucía; Jaramillo, Juan Felipe; Sarmiento, Diana; Alexander, Neal; Stenström, Thor Axel; Overgaard, Hans J

    2015-09-01

    Dengue and other vector-borne diseases are of great public health importance in Colombia. Vector surveillance and control activities are often focused at the household level. Little is known about the importance of nonhousehold sites, including schools, in maintaining vector-borne disease transmission. The objectives of this paper were to determine the mosquito species composition in rural schools in 2 municipalities in Colombia and to assess the potential risk of vector-borne disease transmission in school settings. Entomological surveys were carried out in rural schools during the dry and rainy seasons of 2011. A total of 12 mosquito species were found: Aedes aegypti, Anopheles pseudopunctipennis, Culex coronator, Cx. quinquefasciatus, and Limatus durhamii in both immature and adult forms; Ae. fluviatilis, Cx. nigripalpus, Cx. corniger, and Psorophora ferox in immature forms only; and Ae. angustivittatus, Haemagogus equinus, and Trichoprosopon lampropus in adult forms only. The most common mosquito species was Cx. quinquefasciatus. Classrooms contained the greatest abundance of adult female Ae. aegypti and Cx. quinquefasciatus. The most common Ae. aegypti breeding sites were containers classified as "others" (e.g., cans), followed by containers used for water storage. A high level of Ae. aegypti infestation was found during the wet season. Our results suggest that rural schools are potentially important foci for the transmission of dengue and other mosquito-borne diseases. We propose that public health programs should be implemented in rural schools to prevent vector-borne diseases.

  10. The global compendium of Aedes aegypti and Ae. albopictus occurrence.

    PubMed

    Kraemer, Moritz U G; Sinka, Marianne E; Duda, Kirsten A; Mylne, Adrian; Shearer, Freya M; Brady, Oliver J; Messina, Jane P; Barker, Christopher M; Moore, Chester G; Carvalho, Roberta G; Coelho, Giovanini E; Van Bortel, Wim; Hendrickx, Guy; Schaffner, Francis; Wint, G R William; Elyazar, Iqbal R F; Teng, Hwa-Jen; Hay, Simon I

    2015-01-01

    Aedes aegypti and Ae. albopictus are the main vectors transmitting dengue and chikungunya viruses. Despite being pathogens of global public health importance, knowledge of their vectors' global distribution remains patchy and sparse. A global geographic database of known occurrences of Ae. aegypti and Ae. albopictus between 1960 and 2014 was compiled. Herein we present the database, which comprises occurrence data linked to point or polygon locations, derived from peer-reviewed literature and unpublished studies including national entomological surveys and expert networks. We describe all data collection processes, as well as geo-positioning methods, database management and quality-control procedures. This is the first comprehensive global database of Ae. aegypti and Ae. albopictus occurrence, consisting of 19,930 and 22,137 geo-positioned occurrence records respectively. Both datasets can be used for a variety of mapping and spatial analyses of the vectors and, by inference, the diseases they transmit.

  11. Mathematical model of temephos resistance in Aedes aegypti mosquito population

    NASA Astrophysics Data System (ADS)

    Aldila, D.; Nuraini, N.; Soewono, E.; Supriatna, A. K.

    2014-03-01

    Aedes aegypti is the main vector of dengue disease in many tropical and sub-tropical countries. Dengue became major public concern in these countries due to the unavailability of vaccine or drugs for dengue disease in the market. Hence, the only way to control the spread of DF and DHF is by controlling the vectors carrying the disease, for instance with fumigation, temephos or genetic manipulation. Many previous studies conclude that Aedes aegypti may develop resistance to many kind of insecticide, including temephos. Mathematical model for transmission of temephos resistance in Aedes aegypti population is discussed in this paper. Nontrivial equilibrium point of the system and the corresponding existence are shown analytically. The model analysis have shown epidemiological trends condition that permits the coexistence of nontrivial equilibrium is given analytically. Numerical results are given to show parameter sensitivity and some cases of worsening effect values for illustrating possible conditions in the field.

  12. Effect of temperature on the population dynamics of Aedes aegypti

    NASA Astrophysics Data System (ADS)

    Yusoff, Nuraini; Tokachil, Mohd Najir

    2015-10-01

    Aedes aegypti is one of the main vectors in the transmission of dengue fever. Its abundance may cause the spread of the disease to be more intense. In the study of its biological life cycle, temperature was found to increase the development rate of each stage of this species and thus, accelerate the process of the development from egg to adult. In this paper, a Lefkovitch matrix model will be used to study the stage-structured population dynamics of Aedes aegypti. In constructing the transition matrix, temperature will be taken into account. As a case study, temperature recorded at the Subang Meteorological Station for year 2006 until 2010 will be used. Population dynamics of Aedes aegypti at maximum, average and minimum temperature for each year will be simulated and compared. It is expected that the higher the temperature, the faster the mosquito will breed. The result will be compared to the number of dengue fever incidences to see their relationship.

  13. Stage-Structured Population Dynamics of AEDES AEGYPTI

    NASA Astrophysics Data System (ADS)

    Yusoff, Nuraini; Budin, Harun; Ismail, Salemah

    Aedes aegypti is the main vector in the transmission of dengue fever, a vector-borne disease affecting world population living in tropical and sub-tropical countries. Better understanding of the dynamics of its population growth will help in the efforts of controlling the spread of this disease. In looking at the population dynamics of Aedes aegypti, this paper explored the stage-structured modeling of the population growth of the mosquito using the matrix population model. The life cycle of the mosquito was divided into five stages: eggs, larvae, pupae, adult1 and adult2. Developmental rates were obtained for the average Malaysian temperature and these were used in constructing the transition matrix for the matrix model. The model, which was based only on temperature, projected that the population of Aedes aegypti will blow up with time, which is not realistic. For further work, other factors need to be taken into account to obtain a more realistic result.

  14. Evaluation of ultra-low-volume insecticide dispensing systems for use in single-engined aircraft and their effectiveness against Aedes aegypti populations in South-East Asia*

    PubMed Central

    Kilpatrick, John W.; Tonn, Robert J.; Jatanasen, Sujarti

    1970-01-01

    An evaluation study of ultra-low-volume (ULV) spraying of insecticide from aircraft was carried out in Thailand, to determine if this technique could be used for the emergency control of Aedes aegypti, the major vector of haemorrhagic fever. A small, single-engined aircraft, a Cessna-180, was used in the trials and 2 types of spraying equipment were tested; both were found to be equally effective. The aircraft was fitted with 6 spraying nozzles and flew at an altitude of 150 feet (46 m) at a speed of 100 miles/h (161 km/h). The insecticide used was 95% technical grade malathion and swaths 75 feet wide (22.8 m) were laid down; the rate of application was 3 US fl oz/acre (219 ml/ha). Trials were made in 3 villages near Bangkok and it became apparent that a small aircraft could not produce the required even distribution of insecticide; the rate of application was therefore increased to 6 US fl oz/acre (438 ml/ha). This increased rate appeared to compensate for the narrow width of the swath and produced very satisfactory mortalities in caged mosquitos as well as in natural populations. The size and distribution of droplets was monitored by the use of oil-sensitive red dye cards which showed that there was a good penetration of insecticide into dwellings, etc. Trial results were evaluated by biting counts, bioassays of Aedes and Culex adults and larvae, Culex dips and ovitraps. Biossays indicated that the 6 US fl oz/acre rate of application was almost 100% effective in the open and produced satisfactory mortalities inside markets and dwellings. It was concluded that larger aircraft would be required to treat areas of more than 1000 acres (405 ha) and congested city areas but that the rate of application of insecticide could be considerably lower. Nevertheless, small aircraft can be useful in smaller and less congested areas. PMID:5309517

  15. [Lethal effect of Cuban Myrtaceae on Aedes aegypti (Diptera Cuilicidae)].

    PubMed

    Aguilera, Lucita; Navarro, Agustín; Tacoronte, Juan E; Leyva, Maureen; Marquetti, María C

    2003-01-01

    The biological activity of the essential foliar oils from 2 Cuban endemic Myrtaceae: Eugenia melanadenia and Psidium rotundatum on A. aegypti larvae was evaluated for the first time at the laboratory level. The probit-log analysis of the results showed the larvicidal effect of both oils with values of CL50 = 0.0085% and CL95 = 0.0104% for E. melanadenia and CL50 = 0.0063% and CL95 = 0.0071% for O. rotundatum. Besides, the diagnostic concentration for both essential oils are given and the possible implications of these findings on field populations of A. aegypti are suggessted. PMID:15849965

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

    PubMed

    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. Vector Competence of Culex neavei (Diptera: Culicidae) for Usutu Virus

    PubMed Central

    Nikolay, Birgit; Diallo, Mawlouth; Faye, Ousmane; Boye, Cheikh S.; Sall, Amadou A.

    2012-01-01

    Usutu virus (USUV), a flavivirus belonging to the Japanese encephalitis serocomplex, was isolated for the first time from a Culex neavei mosquito in 1959 in South Africa. Despite multiple isolations of USUV from Cx. neavei in Africa, its vector competence remains unproven. Therefore, we infected Cx. neavei orally with the USUV reference strain and used reverse transcription–polymerase chain reaction and an indirect immunofluorescence assay to detect virus in bodies, legs, wings, and saliva of mosquitoes. We demonstrated the susceptibility of Cx. neavei mosquitoes for the USUV reference strain, its potential to be transmitted, and infection, dissemination, and transmission rates of 90.9%, 40.0%, and 81.3%, respectively. Also, we showed that infection rates are dependent on the virus titer of the blood meal. Given the bionomics of Cx. neavei, its role as enzootic vector for USUV in Africa in a mosquito-bird transmission cycle or as bridge vector for USUV transmission to humans is discussed. PMID:22665607

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

    PubMed

    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. PMID:24961030

  19. La Crosse Virus Field Detection and Vector Competence of Culex Mosquitoes

    PubMed Central

    Harris, M. Camille; Yang, Fan; Jackson, Dorian M.; Dotseth, Eric J.; Paulson, Sally L.; Hawley, Dana M.

    2015-01-01

    La Crosse virus (LACV), a leading cause of arboviral pediatric encephalitis in the United States, is emerging in Appalachia. Here, we report field and laboratory evidence that suggest LACV may be using Culex mosquitoes as additional vectors in this region. This bunyavirus was detected by reverse-transcriptase polymerase chain reaction in two pools of Culex mosquitoes in southwestern Virginia and in six pools in West Virginia. To assess vector competence, we offered LACV blood meals to field-collected Culex restuans Theobald, Cx. pipiens L., and Aedes triseriatus (Say). Both Culex species were susceptible to infection. LACV-positive salivary expectorate, indicative of the ability to transmit, was detected in a small proportion of Cx. restuans (9%) and Cx. pipiens (4%) compared with Ae. triseriatus (40%). In a companion study of Cx. restuans only, we found that adults derived from nutritionally stressed larvae were significantly more likely to disseminate and transmit LACV. Our results indicate a potential role of Culex spp. in LACV dynamics that should be explored further in endemic areas. PMID:26175029

  20. Molecular cloning and preliminary function study of iron responsive element binding protein 1 gene from cypermethrin-resistant Culex pipiens pallens

    PubMed Central

    2011-01-01

    Background Insecticide resistance jeopardizes the control of mosquito populations and mosquito-borne disease control, which creates a major public health concern. Two-dimensional electrophoresis identified one protein segment with high sequence homology to part of Aedes aegypti iron-responsive element binding protein (IRE-BP). Method RT-PCR and RACE (rapid amplification of cDNA end) were used to clone a cDNA encoding full length IRE-BP 1. Real-time quantitative RT-PCR was used to evaluate the transcriptional level changes in the Cr-IRE strain Aedes aegypti compared to the susceptible strain of Cx. pipiens pallens. The expression profile of the gene was established in the mosquito life cycle. Methyl tritiated thymidine (3H-TdR) was used to observe the cypermethrin resistance changes in C6/36 cells containing the stably transfected IRE-BP 1 gene of Cx. pipiens pallens. Results The complete sequence of iron responsive element binding protein 1 (IRE-BP 1) has been cloned from the cypermethrin-resistant strain of Culex pipiens pallens (Cr-IRE strain). Quantitative RT-PCR analysis indicated that the IRE-BP 1 transcription level was 6.7 times higher in the Cr-IRE strain than in the susceptible strain of 4th instar larvae. The IRE-BP 1 expression was also found to be consistently higher throughout the life cycle of the Cr-IRE strain. A protein of predicted size 109.4 kDa has been detected by Western blotting in IRE-BP 1-transfected mosquito C6/36 cells. These IRE-BP 1-transfected cells also showed enhanced cypermethrin resistance compared to null-transfected or plasmid vector-transfected cells as determined by 3H-TdR incorporation. Conclusion IRE-BP 1 is expressed at higher levels in the Cr-IRE strain, and may confer some insecticide resistance in Cx. pipiens pallens. PMID:22075242

  1. Laboratory study on the mosquito larvicidal properties of leaf and seed extract of the plant Agave americana.

    PubMed

    Dharmshaktu, N S; Prabhakaran, P K; Menon, P K

    1987-04-01

    Experiments on the leaf extract tested against three mosquito species led to 100% mortality of stage 4 Anopheles, Aedes and Culex larvae at a concentration of 0.08% within 24-48 h, whereas 100% mortality of stage 1 larvae occurred at lower concentrations: 0.0032% for Aedes aegypti, 0.016% for Culex quinquefasciatus and 0.08% for Anopheles stephensi, and was more rapid. At the end of 24 h, the highest dilution of the seed extract studied (1:200) produces a larval mortality of 100% for Anopheles and Aedes and 56% for Culex spp., when 4th instar larvae were exposed at room temperature. The comparative mortality in the control group was negligible. One hundred per cent mortality of Anopheles larvae took place by the end of 10 h, and of Aedes larvae by 17 h, at a dilution of 1:200 with water.

  2. [Comparative characteristics of intergenic spacers of ribosomal RNA gene cluster in mosquitoes of the genus Culex (Diptera: Culicidae)].

    PubMed

    Shaĭkevich, E V; Zagoskin, M V; Mukha, D V

    2013-01-01

    Nucleotide sequences of intergenic spacer of ribosomal RNA gene cluster (rIGS) were identified in mosquitoes Culex modestus, Culex torrentium and Culex pipiens pallens. The level of interpopulation variability of the rIGS in the subspecies C. pipiens pipiens (form pipiens--mosquitoes that inhabit the open waters, and form molestus--mosquitoes that inhabit basements) living in Russia was estimated. No extensive repetitive sequences characteristic of the rIGS of all previously described species of mosquitoes were found within the rIGS of Culex mosquitoes. At the same time, evolutionarily conserved motifs and relatively short degenerate sequences of different classes of transposable elements, as well as multiple blocks of variable microsatellite repeats were identified. Our data demonstrated that the rIGS of Culex mosquitoes can be considered as a promising molecular marker for the analysis of population and phylogenetic relationships within this group of insects.

  3. Dispersal of Culex Mosquitoes (Diptera: Culicidae) From a Wastewater Treatment Facility

    PubMed Central

    Ciota, Alexander T.; Drummond, Cori L.; Ruby, Meghan A.; Drobnack, Jason; Ebel, Gregory D.; Kramer, Laura D.

    2012-01-01

    A mark-recapture project examined dispersal and flight distances of Culex mosquitoes from a wastewater treatment plant in Albany, NY, during 2007 and 2008. A self-marking device was constructed to mark egressing mosquitoes with fluorescent marking powder. Mosquitoes were recaptured using 30 CDC miniature light traps located within a 2.0 km radius of the marking site. A total of 13 and 10 marked Culex mosquitoes were recaptured in 2007 and 2008, respectively. Culex mosquitoes traveled a minimum of 0.16 km, a maximum of 1.98 km and, following correction for decreasing trap density with distance, had a mean distance traveled of 1.33 km. Characterizing the dispersal patterns of these mosquitoes is important for understanding the distribution of West Nile virus and other pathogens. PMID:22308769

  4. Cytochromr b expression and RNAi knockdown in Aedes aegypti.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cytochrome b, coded by mitochondrial DNA, is one of the cytochromes involved in the electron transport in the respiratory chain of mitochondria. Cytochrome b is a critical intermediate in mitoptosis, i.e. a mitochondrial death pathway. To reveal whether cytochrome b of the mosquito Aedes aegypti (Ae...

  5. Pyrethroid resistance is widespread among Florida populations of Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aedes aegypti is an efficient vector of a number of diseases that affect man and is of increasing concern because of the reemergence of dengue and recent identification of locally acquired chikungunya in Florida. Pesticide resistance in this species has been demonstrated in several neighboring coun...

  6. USDA Research on New Strategies for Controlling Aedes aegypti.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    USDA researchers are currently studying new methods to control Aedes aegypti. One involves molecular pesticides which target critical genes/proteins (such as inhibitors of apoptosis proteins, IAPs) in mosquitoes using RNA interference (RNAi). RNAi constructs are evaluated in vivo in adult mosquito...

  7. Experimental Transmission of Mayaro Virus by Aedes aegypti

    PubMed Central

    Long, Kanya C.; Ziegler, Sarah A.; Thangamani, Saravanan; Hausser, Nicole L.; Kochel, Tadeusz J.; Higgs, Stephen; Tesh, Robert B.

    2011-01-01

    Outbreaks of Mayaro fever have been associated with a sylvatic cycle of Mayaro virus (MAYV) transmission in South America. To evaluate the potential for a common urban mosquito to transmit MAYV, laboratory vector competence studies were performed with Aedes aegypti from Iquitos, Peru. Oral infection in Ae. aegypti ranged from 0% (0/31) to 84% (31/37), with blood meal virus titers between 3.4 log10 and 7.3 log10 plaque-forming units (PFU)/mL. Transmission of MAYV by 70% (21/30) of infected mosquitoes was shown by saliva collection and exposure to suckling mice. Amount of viral RNA in febrile humans, determined by real-time polymerase chain reaction, ranged from 2.7 to 5.3 log10 PFU equivalents/mL. Oral susceptibility of Ae. aegypti to MAYV at titers encountered in viremic humans may limit opportunities to initiate an urban cycle; however, transmission of MAYV by Ae. aegypti shows the vector competence of this species and suggests potential for urban transmission. PMID:21976583

  8. A review on symmetries for certain Aedes aegypti models

    NASA Astrophysics Data System (ADS)

    Freire, Igor Leite; Torrisi, Mariano

    2015-04-01

    We summarize our results related with mathematical modeling of Aedes aegypti and its Lie symmetries. Moreover, some explicit, group-invariant solutions are also shown. Weak equivalence transformations of more general reaction diffusion systems are also considered. New classes of solutions are obtained.

  9. Integrated proteomic and transcriptomic analysis of the Aedes aegypti eggshell

    PubMed Central

    2014-01-01

    Background Mosquito eggshells show remarkable diversity in physical properties and structure consistent with adaptations to the wide variety of environments exploited by these insects. We applied proteomic, transcriptomic, and hybridization in situ techniques to identify gene products and pathways that participate in the assembly of the Aedes aegypti eggshell. Aedes aegypti population density is low during cold and dry seasons and increases immediately after rainfall. The survival of embryos through unfavorable periods is a key factor in the persistence of their populations. The work described here supports integrated vector control approaches that target eggshell formation and result in Ae. aegypti drought-intolerant phenotypes for public health initiatives directed to reduce mosquito-borne diseases. Results A total of 130 proteins were identified from the combined mass spectrometric analyses of eggshell preparations. Conclusions Classification of proteins according to their known and putative functions revealed the complexity of the eggshell structure. Three novel Ae. aegypti vitelline membrane proteins were discovered. Odorant-binding and cysteine-rich proteins that may be structural components of the eggshell were identified. Enzymes with peroxidase, laccase and phenoloxidase activities also were identified, and their likely involvements in cross-linking reactions that stabilize the eggshell structure are discussed. PMID:24707823

  10. Repellent activity of selected essential oils against Aedes aegypti.

    PubMed

    Choochote, W; Chaithong, U; Kamsuk, K; Jitpakdi, A; Tippawangkosol, P; Tuetun, B; Champakaew, D; Pitasawat, B

    2007-07-01

    Essential oils extracted from ten plant species were screened for repellency against Aedes aegypti mosquitoes. Three oils; Zanthoxylum piperitum, Anethum graveolens and Kaempferia galanga, exerted protection against A. aegypti, with median complete-protection times of 1, 0.5 and 0.25 h, respectively. The protection times were increased significantly by incorporating 10% vanillin. The highest potential was established from Z. piperitum oil +10% vanillin (2.5 h, range=1-2.5 h). Mixtures from pairs of the effective oils possessed slight repellency that ranged from 0-0.5 h. None of the oil combinations repelled A. aegypti for longer than their constituent oil alone. With vanillin added, however, each oil mixture provided improved protection, which was approximately equal to oil on its own. GC/MS analysis revealed that the main component of Z. piperitum fruit oil was limonene (37.99%), with minor amounts of sabinene (13.30%) and beta-myrcene (7.17%). Repellent testing of stored samples of Z. piperitum fruit oil against A. aegypti demonstrated that repellent activity of those kept at -20 degrees C or 4 degrees C was present for a period of at least 3 months. Therefore, the essential oil of Z. piperitum fruit may prove useful in the development of mosquito repellents as an effective personal protection measure against mosquito bites. PMID:17512681

  11. Experience- and age-mediated oviposition behaviour in the yellow fever mosquito Stegomyia aegypti (=Aedes aegypti).

    PubMed

    Ruktanonchai, N W; Lounibos, L P; Smith, D L; Allan, S A

    2015-09-01

    In repeated behaviours such as those of feeding and reproduction, past experiences can inform future behaviour. By altering their behaviour in response to environmental stimuli, insects in highly variable landscapes can tailor their behaviour to their particular environment. In particular, female mosquitoes may benefit from plasticity in their choice of egg-laying site as these sites are often temporally variable and clustered. The opportunity to adapt egg-laying behaviour to past experience also exists for mosquito populations as females typically lay eggs multiple times throughout their lives. Whether experience and age affect egg-laying (or oviposition) behaviour in the mosquito Stegomyia aegypti (=Aedes aegypti) (Diptera: Culicidae) was assessed using a wind tunnel. Initially, gravid mosquitoes were provided with a cup containing either repellent or well water. After ovipositing in these cups, the mosquitoes were blood-fed and introduced into a wind tunnel. In this wind tunnel, an oviposition cup containing repellent was placed in the immediate vicinity of the gravid mosquitoes. A cup containing well water was placed at the opposite end of the tunnel so that if the females flew across the chamber, they encountered the well water cup, in which they readily laid eggs. Mosquitoes previously exposed to repellent cups became significantly more likely to later lay eggs in repellent cups, suggesting that previous experience with suboptimal oviposition sites informs mosquitoes of the characteristics of nearby oviposition sites. These results provide further evidence that mosquitoes modify behaviour in response to environmental information and are demonstrated in a vector species in which behavioural plasticity may be ecologically and epidemiologically meaningful.

  12. Epidemiological significance of the breeding of mosquitoes in discarded automobile tyres in Zaria, Northern Nigeria.

    PubMed

    Adebote, D A; Kogi, E; Oniye, S J; Akoje, F

    2011-09-01

    Waste automobile tyres are suitable receptacles of rainwater thus capable of supporting the breeding of vector mosquito species in close proximity to humans and altering disease transmission risks. Bionomics of mosquitoes in carelessly discarded tyres was explored to unravel species composition and abundance, physicochemical parameters of microhabitats and epidemiological significance. Of the 1179 larvae isolated from 90/212 (42.45%) positive tyres were ten species belonging to Aedes and Culex genera, including Aedes aegypti (46.56%), Culex albiventris (0.25%), Cx. cinereus (0.25%), Cx. grahami (0.68%), Cx. ingrami (1.44%), Cx. nebulosus (2.37%), Cx. mirificus (0.08%), Cx. pipiens pipiens (0.17%), Cx. quinquefasciatus (47.07%) and Cx. tigripes (1.10%). Abundance of the dominant Ae. aegypti and Cx. quinquefasciatus did not differ significantly (P > 0.05), but was higher than those of the other eight species (P < 0.05). The microhabitat pH (range 5.20-9.50), total dissolved solids (range 15-802 ppm) and electrical conductivity (range 30-1603 microscm 1) were obtained in tyres. Abundance of Cx. quinquefasciatus correlated positively and significantly with EC and TDS of breeding water (P < 0.05). The study revealed high potential of the transmission of filariasis and arboviruses including dengue and yellow fever by mosquitoes domiciled in waste tyres.

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

    PubMed

    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.

  14. Diversification of Wolbachia endosymbiont in the Culex pipiens mosquito.

    PubMed

    Atyame, Célestine M; Delsuc, Frédéric; Pasteur, Nicole; Weill, Mylène; Duron, Olivier

    2011-10-01

    The α-proteobacteria Wolbachia are among the most common intracellular bacteria and have recently emerged as important drivers of arthropod biology. Wolbachia commonly act as reproductive parasites in arthropods by inducing cytoplasmic incompatibility (CI), a type of conditional sterility between hosts harboring incompatible infections. In this study, we examined the evolutionary histories of Wolbachia infections, known as wPip, in the common house mosquito Culex pipiens, which exhibits the greatest variation in CI crossing patterns observed in any insect. We first investigated a panel of 20 wPip strains for their genetic diversity through a multilocus scheme combining 13 Wolbachia genes. Because Wolbachia depend primarily on maternal transmission for spreading within arthropod populations, we also studied the variability in the coinherited Cx. pipiens mitochondria. In total, we identified 14 wPip haplotypes, which all share a monophyletic origin and clearly cluster into five distinct wPip groups. The diversity of Cx. pipiens mitochondria was extremely reduced, which is likely a consequence of cytoplasmic hitchhiking driven by a unique and recent Wolbachia invasion. Phylogenetic evidence indicates that wPip infections and mitochondrial DNA have codiverged through stable cotransmission within the cytoplasm and shows that a rapid diversification of wPip has occurred. The observed pattern demonstrates that a considerable degree of Wolbachia diversity can evolve within a single host species over short evolutionary periods. In addition, multiple signatures of recombination were found in most wPip genomic regions, leading us to conclude that the mosaic nature of wPip genomes may play a key role in their evolution.

  15. [Effect of lethal ovitrap on the longevity of females of Aedes aegypti (Diptera: Culicidae)].

    PubMed

    Gama, Renata Antonaci; Eiras, Alvaro Eduardo; Resende, Marcelo Carvalho de

    2007-01-01

    Oviposition traps with added insecticide may work as a new method for controlling the females of the Aedes aegypti mosquito. Females of Aedes aegypti were placed in contact with lethal ovitraps with aging. The mortality rate ranged from 60.3% to 100%. The effect of aging the slats impregnated with deltamethrin was significant in relation to the percentage mortality among Aedes aegypti females. PMID:18200416

  16. Patterns of Geographic Expansion of Aedes aegypti in the Peruvian Amazon

    PubMed Central

    Guagliardo, Sarah Anne; Barboza, José Luis; Morrison, Amy C.; Astete, Helvio; Vazquez-Prokopec, Gonzalo; Kitron, Uriel

    2014-01-01

    Background and Objectives In the Peruvian Amazon, the dengue vector Aedes aegypti is abundant in large urban centers such as Iquitos. In recent years, it has also been found in a number of neighboring rural communities with similar climatic and socioeconomic conditions. To better understand Ae. aegypti spread, we compared characteristics of communities, houses, and containers in infested and uninfested communities. Methods We conducted pupal-demographic surveys and deployed ovitraps in 34 communities surrounding the city of Iquitos. Communities surveyed were located along two transects: the Amazon River and a 95km highway. We calculated entomological indices, mapped Ae. aegypti presence, and developed univariable and multivariable logistic regression models to predict Ae. aegypti presence at the community, household, or container level. Results Large communities closer to Iquitos were more likely to be infested with Ae. aegypti. Within infested communities, houses with Ae. aegypti had more passively-filled containers and were more often infested with other mosquito genera than houses without Ae. aegypti. For containers, large water tanks/drums and containers with solar exposure were more likely to be infested with Ae. aegypti. Maps of Ae. aegypti presence revealed a linear pattern of infestation along the highway, and a scattered pattern along the Amazon River. We also identified the geographical limit of Ae. aegypti expansion along the highway at 19.3 km south of Iquitos. Conclusion In the Peruvian Amazon, Ae. aegypti geographic spread is driven by human transportation networks along rivers and highways. Our results suggest that urban development and oviposition site availability drive Ae. aegypti colonization along roads. Along rivers, boat traffic is likely to drive long-distance dispersal via unintentional transport of mosquitoes on boats. PMID:25101786

  17. Adulticidal & larvicidal efficacy of three neonicotinoids against insecticide susceptible & resistant mosquito strains

    PubMed Central

    Uragayala, Sreehari; Verma, Vaishali; Natarajan, Elamathi; Velamuri, Poonam Sharma; Kamaraju, Raghavendra

    2015-01-01

    Background & objectives: Due to ever growing insecticide resistance in mosquitoes to commonly used insecticides in many parts of the globe, there is always a need for introduction of new insecticides for the control of resistant vector mosquitoes. In this study, larvicidal and adulticidal efficacies of three neonicotinoids (imidacloprid, thiacloprid and thiamethoxam) were tested against resistant and susceptible populations of Anopheles stephensi Liston 1901, Aedes (Stegomyia) aegypti Linnaeus, and Culex quinquefasciatus Say (Diptera: Culicidae). Methods: Laboratory-reared mosquito species were used. Insecticide susceptibility tests were done using standard WHO procedures and using diagnostic dosages of insecticide test papers and larvicides. Adulticidal efficacy of candidate insecticides was assessed using topical application method and larval bioassays were conducted using standard WHO procedure. Results: The results of topical application on 3-5 day old female mosquitoes indicated that resistant strain of An. stephensi registered lower LC50 values than the susceptible strain. Among the three insecticides tested, thiacloprid was found more effective than the other two insecticides. Culex quinquefasciatus registered lowest LC50 for imidacloprid than the other two mosquito species tested. In larval bioassays, the LC50 values registered for imidacloprid were in the order of Cx. quinquefasciatus aegypti. In case of thiacloprid, the order of efficacy (LC50) was Cx. quinquefasciatus quinquefasciatus. Interpretation & conclusions: The present study indicated that insecticide resistant strains of mosquito species tested showed more susceptibility to the three neonicotinoids tested, and the possibility of using neonicotinoids for the control of resistant mosquitoes

  18. Comparative efficacy of existing surveillance tools for Aedes aegypti in Western Kenya.

    PubMed

    Yalwala, Sancto; Clark, Jeffrey; Oullo, David; Ngonga, Daniel; Abuom, David; Wanja, Elizabeth; Bast, Joshua

    2015-12-01

    All traditional surveillance techniques for Aedes aegypti have been developed for the cosmopolitan domestic subspecies Ae. aegypti aegypti, and not the sylvatic subspecies, Ae. aegypti formosus. The predominant form in Western Kenya is Ae. aegypti formosus that is rarely associated with human habitations but is linked to transmission of sylvatic dengue virus strains. We compared five surveillance methods for their effectiveness in sampling Ae. aegypti formosus with the goal of determining a sustainable surveillance strategy in Kenya. The methods included larval and pupal surveys, oviposition trapping, BG-Sentinel trapping, resting boxes, and backpack aspirations. Larval and pupal surveys collected the highest number of Ae. aegypti formosus (51.3%), followed by oviposition traps (45.7%), BG-Sentinel traps (3.0%), and zero collected with either backpack aspiration or resting box collections. No Ae. aegypti formosus larvae or pupae were found indoors. The results indicate that oviposition traps and outdoor larval and pupal surveys were better surveillance methods for Ae. aegypti formosus in Western Kenya. PMID:26611965

  19. Comparative efficacy of existing surveillance tools for Aedes aegypti in Western Kenya.

    PubMed

    Yalwala, Sancto; Clark, Jeffrey; Oullo, David; Ngonga, Daniel; Abuom, David; Wanja, Elizabeth; Bast, Joshua

    2015-12-01

    All traditional surveillance techniques for Aedes aegypti have been developed for the cosmopolitan domestic subspecies Ae. aegypti aegypti, and not the sylvatic subspecies, Ae. aegypti formosus. The predominant form in Western Kenya is Ae. aegypti formosus that is rarely associated with human habitations but is linked to transmission of sylvatic dengue virus strains. We compared five surveillance methods for their effectiveness in sampling Ae. aegypti formosus with the goal of determining a sustainable surveillance strategy in Kenya. The methods included larval and pupal surveys, oviposition trapping, BG-Sentinel trapping, resting boxes, and backpack aspirations. Larval and pupal surveys collected the highest number of Ae. aegypti formosus (51.3%), followed by oviposition traps (45.7%), BG-Sentinel traps (3.0%), and zero collected with either backpack aspiration or resting box collections. No Ae. aegypti formosus larvae or pupae were found indoors. The results indicate that oviposition traps and outdoor larval and pupal surveys were better surveillance methods for Ae. aegypti formosus in Western Kenya.

  20. Binding of a fluorescence reporter and a ligand to an odorant-binding protein of the yellow fever mosquito, Aedes aegypti

    PubMed Central

    Leal, Gabriel M.; Leal, Walter S.

    2015-01-01

    Odorant-binding proteins (OBPs), also named pheromone-binding proteins when the odorant is a pheromone, are essential for insect olfaction. They solubilize odorants that reach the port of entry of the olfactory system, the pore tubules in antennae and other olfactory appendages. Then, OBPs transport these hydrophobic compounds through an aqueous sensillar lymph to receptors embedded on dendritic membranes of olfactory receptor neurons. Structures of OBPs from mosquito species have shed new light on the mechanism of transport, although there is considerable debate on how they deliver odorant to receptors. An OBP from the southern house mosquito, Culex quinquefasciatus, binds the hydrophobic moiety of a mosquito oviposition pheromone (MOP) on the edge of its binding cavity. Likewise, it has been demonstrated that the orthologous protein from the malaria mosquito binds the insect repellent DEET on a similar edge of its binding pocket. A high school research project was aimed at testing whether the orthologous protein from the yellow fever mosquito, AaegOBP1, binds DEET and other insect repellents, and MOP was used as a positive control. Binding assays using the fluorescence reporter N-phenyl-1-naphtylamine (NPN) were inconclusive. However, titration of NPN fluorescence emission in AaegOBP1 solution with MOP led to unexpected and intriguing results. Quenching was observed in the initial phase of titration, but addition of higher doses of MOP led to a stepwise increase in fluorescence emission coupled with a blue shift, which can be explained at least in part by formation of MOP micelles to house stray NPN molecules. PMID:25671088

  1. Efficacy and persistence of Altosid pellets against Culex species in catch basins in Michigan.

    PubMed

    McCarry, M J

    1996-03-01

    Larvae of Culex pipiens and Cx. restuans in catch basins were exposed to Altosid pellets (4% active ingredient, [S]-methoprene) applied at a rate of 11.3 kg/ha (7 g of pellets per catch basin). Under field conditions, the pellets yielded an average 82% emergence inhibition of adult mosquitoes over the 15-wk trial period.

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

    PubMed

    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.

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

    PubMed Central

    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

  4. Improved high-throughput method for molecular identification of Culex mosquitoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Culex pipiens, Cx. restuans, and Cx. salinarius play important and most likely different roles in transmission of West Nile Virus (WNV) in the northeastern United Sates. While Cx. pipiens and Cx. restuans are considered the main enzootic vectors of WNV, Cx. salinarius may be involved in epizootic cy...

  5. Transcriptional Regulation of Culex pipiens Mosquitoes by Wolbachia Influences Cytoplasmic Incompatibility

    PubMed Central

    Harris, Simon; Kambris, Zakaria; Sutton, Elizabeth R.; Bonsall, Michael B.; Parkhill, Julian; Sinkins, Steven P.

    2013-01-01

    Cytoplasmic incompatibility (CI) induced by the endosymbiont Wolbachia pipientis causes complex patterns of crossing sterility between populations of the Culex pipiens group of mosquitoes. The molecular basis of the phenotype is yet to be defined. In order to investigate what host changes may underlie CI at the molecular level, we examined the transcription of a homolog of the Drosophila melanogaster gene grauzone that encodes a zinc finger protein and acts as a regulator of female meiosis, in which mutations can cause sterility. Upregulation was observed in Wolbachia-infected C. pipiens group individuals relative to Wolbachia-cured lines and the level of upregulation differed between lines that were reproductively incompatible. Knockdown analysis of this gene using RNAi showed an effect on hatch rates in a Wolbachia infected Culex molestus line. Furthermore, in later stages of development an effect on developmental progression in CI embryos occurs in bidirectionally incompatible crosses. The genome of a wPip Wolbachia strain variant from Culex molestus was sequenced and compared with the genome of a wPip variant with which it was incompatible. Three genes in inserted or deleted regions were newly identified in the C. molestus wPip genome, one of which is a transcriptional regulator labelled wtrM. When this gene was transfected into adult Culex mosquitoes, upregulation of the grauzone homolog was observed. These data suggest that Wolbachia-mediated regulation of host gene expression is a component of the mechanism of cytoplasmic incompatibility. PMID:24204251

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

    PubMed Central

    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

  7. Evaluation of Mosquito Repellent Activity of Isolated Oleic Acid, Eicosyl Ester from Thalictrum javanicum

    PubMed Central

    Gurunathan, Abinaya; Senguttuvan, Jamuna; Paulsamy, S.

    2016-01-01

    To evaluate the traditional use, the mosquito repellent property of Thalictrum javanicum and to confirm the predicted larvicidal activity of the isolated compound, oleic acid, eicosyl ester from its aerial parts by PASS software, the present study was carried out using 4th instar stage larvae of the mosquitoes, Aedes aegypti (dengue vector) and Culex quinquefasciatus (filarial vector). Insecticidal susceptibility tests were conducted and the mortality rate was observed after 24 h exposure. The chitinase activity of isolated compound was assessed by using purified β-N-acetyl glucosaminidase (chitinase). Ecdysone 20-monooxygenase assay (radioimmuno assay) was made using the same larval stage of A. aegyptiand C. quinquefasciatus. The results were compared with the crude methanol extract of the whole plant. The isolated compound, oleic acid, eicosyl ester was found to be the most effective larvicide against A. aegypti (LC50/24 h -8.51 ppm) and C. quinquefasciatus (LC50/24 h - 12.5 ppm) than the crude methanol extract (LC50/24 h - 257.03 ppm and LC50/24 h - 281.83 ppm, respectively). The impact of oleic acid, eicosyl ester on reducing the activity of chitinase and ecdysone 20-monooxygenase was most prominent in both the target species, A. aegyptiand C. quinquefasciatus than the control. The results therefore suggest that the compound, oleic acid, eicosyl ester from Thalictrum javanicum may be considered as a potent source of mosquito larvicidal property. PMID:27168688

  8. Evaluation of Mosquito Repellent Activity of Isolated Oleic Acid, Eicosyl Ester from Thalictrum javanicum.

    PubMed

    Gurunathan, Abinaya; Senguttuvan, Jamuna; Paulsamy, S

    2016-01-01

    To evaluate the traditional use, the mosquito repellent property of Thalictrum javanicum and to confirm the predicted larvicidal activity of the isolated compound, oleic acid, eicosyl ester from its aerial parts by PASS software, the present study was carried out using 4th instar stage larvae of the mosquitoes, Aedes aegypti (dengue vector) and Culex quinquefasciatus (filarial vector). Insecticidal susceptibility tests were conducted and the mortality rate was observed after 24 h exposure. The chitinase activity of isolated compound was assessed by using purified β-N-acetyl glucosaminidase (chitinase). Ecdysone 20-monooxygenase assay (radioimmuno assay) was made using the same larval stage of A. aegyptiand C. quinquefasciatus. The results were compared with the crude methanol extract of the whole plant. The isolated compound, oleic acid, eicosyl ester was found to be the most effective larvicide against A. aegypti (LC50/24 h -8.51 ppm) and C. quinquefasciatus (LC50/24 h - 12.5 ppm) than the crude methanol extract (LC50/24 h - 257.03 ppm and LC50/24 h - 281.83 ppm, respectively). The impact of oleic acid, eicosyl ester on reducing the activity of chitinase and ecdysone 20-monooxygenase was most prominent in both the target species, A. aegyptiand C. quinquefasciatus than the control. The results therefore suggest that the compound, oleic acid, eicosyl ester from Thalictrum javanicum may be considered as a potent source of mosquito larvicidal property.

  9. Evaluation of Mosquito Repellent Activity of Isolated Oleic Acid, Eicosyl Ester from Thalictrum javanicum.

    PubMed

    Gurunathan, Abinaya; Senguttuvan, Jamuna; Paulsamy, S

    2016-01-01

    To evaluate the traditional use, the mosquito repellent property of Thalictrum javanicum and to confirm the predicted larvicidal activity of the isolated compound, oleic acid, eicosyl ester from its aerial parts by PASS software, the present study was carried out using 4th instar stage larvae of the mosquitoes, Aedes aegypti (dengue vector) and Culex quinquefasciatus (filarial vector). Insecticidal susceptibility tests were conducted and the mortality rate was observed after 24 h exposure. The chitinase activity of isolated compound was assessed by using purified β-N-acetyl glucosaminidase (chitinase). Ecdysone 20-monooxygenase assay (radioimmuno assay) was made using the same larval stage of A. aegyptiand C. quinquefasciatus. The results were compared with the crude methanol extract of the whole plant. The isolated compound, oleic acid, eicosyl ester was found to be the most effective larvicide against A. aegypti (LC50/24 h -8.51 ppm) and C. quinquefasciatus (LC50/24 h - 12.5 ppm) than the crude methanol extract (LC50/24 h - 257.03 ppm and LC50/24 h - 281.83 ppm, respectively). The impact of oleic acid, eicosyl ester on reducing the activity of chitinase and ecdysone 20-monooxygenase was most prominent in both the target species, A. aegyptiand C. quinquefasciatus than the control. The results therefore suggest that the compound, oleic acid, eicosyl ester from Thalictrum javanicum may be considered as a potent source of mosquito larvicidal property. PMID:27168688

  10. Seasonal abundance of Aedes albopictus in selected urban and suburban areas in Penang, Malaysia.

    PubMed

    Rozilawati, H; Zairi, J; Adanan, C R

    2007-06-01

    Ovitrap surveillance was conducted in a selected urban area and suburban area, ie. Taman Permai Indah(TPI) and Kampung Pasir Gebu (KPG) in Penang for 14 months. It was found that Aedes albopictus was the most abundant Aedes species in both study areas, even though a small percentage of Aedes aegypti and Culex quinquefasciatus were found to breed simultaneously in the same ovitrap. This study indicated that the main dengue vector was Ae. albopictus. A strong correlation was found between rainfall and egg population in both of the study sites (r = 0.982 and r = 0.918). PMID:17568381

  11. Glutathion S-transferase activity and DDT-susceptibility of Malaysian mosquitos.

    PubMed

    Lee, H L; Chong, W L

    1995-03-01

    Comparative DDT-susceptibility status and glutathion s-transferase (GST) activity of Malaysian Anopheles maculatus, Culex quinquefasciatus and Aedes aegypti was investigated to ascertain the role of this enzyme in DDT resistance. The standardised WHO dose-mortality bioassay tests were used to determine DDT susceptibility in these mosquitos, whilst GST microassay (Brogdon and Barber, 1990) was conducted to measure the activity of this enzyme in mosquito homogenate. It appeared that DDT susceptibility status of Malaysian mosquitos was not correlated with GST activity.

  12. Seasonal abundance of Aedes albopictus in selected urban and suburban areas in Penang, Malaysia.

    PubMed

    Rozilawati, H; Zairi, J; Adanan, C R

    2007-06-01

    Ovitrap surveillance was conducted in a selected urban area and suburban area, ie. Taman Permai Indah(TPI) and Kampung Pasir Gebu (KPG) in Penang for 14 months. It was found that Aedes albopictus was the most abundant Aedes species in both study areas, even though a small percentage of Aedes aegypti and Culex quinquefasciatus were found to breed simultaneously in the same ovitrap. This study indicated that the main dengue vector was Ae. albopictus. A strong correlation was found between rainfall and egg population in both of the study sites (r = 0.982 and r = 0.918).

  13. Bioactive compound synthesis of Ag nanoparticles from leaves of Melia azedarach and its control for mosquito larvae.

    PubMed

    Ramanibai, R; Velayutham, K

    2015-02-01

    Larvicidal activity of synthesized Ag nanoparticles using 2,7.bis[2-[diethylamino]-ethoxy]fluorence isolate from the Melia azedarach leaves against Aedes aegypti and Culex quinquefasciatus. Six fractions were collected and concentrated, fraction three showed a single spot on TLC which was found to be a pure compound. The structures were elucidated by analyses of UV, MS, and NMR spectral data. The maximum mortality was fluorence against A. aegypti and C. quinquefasciatus (LC50 = 7.94, LC90 = 23.82 ppm and LC50 = 13.58 and LC90 = 40.03 ppm). The synthesized nanoparticles were characterized and confirmed as Ag nanoparticles by using UV-visible spectroscopy, XRD and HRTEM analysis. The maximum activity was observed in synthesized AgNPs against A. aegypti and C. quinquefasciatus (LC50 = 4.27 and 3.43 µg/mL; LC90 = 12.61 and 10.29 µg/mL). Rephrase test was studied to analyze the toxicological effects of Mesocyclops pehpeiensis for 24 h at synthesized AgNPs. This method is considered as an innovative alternative approach that can be used to control mosquitoes.

  14. Preliminary findings on Bagaza virus (Flavivirus: Flaviviridae) growth kinetics, transmission potential & transovarial transmission in three species of mosquitoes

    PubMed Central

    Sudeep, A.B.; Bondre, V.P.; Mavale, M.S.; Ghodke, Y.S.; George, R.P.; Aher, R.V.; Gokhale, M.D.

    2013-01-01

    Background & objectives: Bagaza virus (BAGV), a flavivirus synonymous with Israel turkey meningoencephalitis virus, has been found to circulate in India. BAGV has recently been held responsible for inducing febrile illness in humans and causing unusually high mortality to wild birds in Spain. A study was therefore, undertaken to determine its replication kinetics in certain mosquitoes and to determine vector competence and potential of the mosquitoes to transmit BAGV experimentally. Methods: Aedes aegypti, Culex tritaeniorhynchus and Cx quinquefasciatus mosquitoes were inoculated with BAGV; samples were harvested every day and titrated in BHK-21 cell line. Vector competence and experimental transmission were determined by examining the saliva of infected mosquitoes for virus and induction of sickness in suckling mice, respectively. Results: Cx. tritaeniorhynchus and Ae. aegypti mosquitoes yielded 5 log10 and 4.67 log10 TCID50/ml of virus on day 3 post-infection (PI), respectively while Cx. quinquefasciatus yielded a titre of 4 log10 TCID50/ml on day 4 PI. BAGV was detected in saliva of all the infected mosquitoes demonstrating their vector competence. Experimental transmission of BAGV to infant mice as well as transovarial transmission was demonstrated by Cx. tritaeniorhynchus but not by Ae. aegypti and Cx. quinquefasciatus mosquitoes. Interpretation & conclusions: Replication of BAGV to high titres and dissemination to saliva in three most prevalent mosquitoes in India is of immense public health importance. Though no major outbreak involving man has been reported yet, BAGV has a potential to cause outbreaks in future. PMID:24056604

  15. [Utilization of the waste of sisal industry in the control of mosquito larvae].

    PubMed

    Pizarro, A P; Oliveira Filho, A M; Parente, J P; Melo, M T; dos Santos, C E; Lima, P R

    1999-01-01

    The aim of this research was to utilize the waste residues of sisal fiber separation from Agave sisalana leaves to develop a larvicide for the combat of mosquito transmitting tropical diseases. Larvae of Aedes aegypti and Culex quinquefasciatus were exposed to different concentrations of the Agave extract for 24 hours to determine lethal concentrations. The LC50 for A. aegypti was 322 ppm and the LC50 for C. quinquefasciatus was 183 ppm. To detect the active substances, saponins were investigated. It was found that the various components of the extract were effective in eliminating the larvae. Under field conditions, this formulation can probably be used at 100 ppm, which causes 100% mortality of C. quinquefasciatus larvae after 3-4 days. The product is not recommended for use against A. aegypti due to the necessity for high concentrations and to the fact that the larvae of this species live frequently on drinking water. To avoid fermentation, Agave extract should be used in a dehydrated form which also represent a good formulation for practical use.

  16. Bioactive compound synthesis of Ag nanoparticles from leaves of Melia azedarach and its control for mosquito larvae.

    PubMed

    Ramanibai, R; Velayutham, K

    2015-02-01

    Larvicidal activity of synthesized Ag nanoparticles using 2,7.bis[2-[diethylamino]-ethoxy]fluorence isolate from the Melia azedarach leaves against Aedes aegypti and Culex quinquefasciatus. Six fractions were collected and concentrated, fraction three showed a single spot on TLC which was found to be a pure compound. The structures were elucidated by analyses of UV, MS, and NMR spectral data. The maximum mortality was fluorence against A. aegypti and C. quinquefasciatus (LC50 = 7.94, LC90 = 23.82 ppm and LC50 = 13.58 and LC90 = 40.03 ppm). The synthesized nanoparticles were characterized and confirmed as Ag nanoparticles by using UV-visible spectroscopy, XRD and HRTEM analysis. The maximum activity was observed in synthesized AgNPs against A. aegypti and C. quinquefasciatus (LC50 = 4.27 and 3.43 µg/mL; LC90 = 12.61 and 10.29 µg/mL). Rephrase test was studied to analyze the toxicological effects of Mesocyclops pehpeiensis for 24 h at synthesized AgNPs. This method is considered as an innovative alternative approach that can be used to control mosquitoes. PMID:25496834

  17. Evaluation of some adhesives for collecting Musca domestica and Chrysomya megacephala adults or mosquito larvae in sticky traps.

    PubMed

    Sulaiman, S; Yunus, H; Sohadi, R

    1987-07-01

    1. Seven types of water-insoluble adhesives were evaluated in sticky traps for collecting adults of Musca domestica L. and Chrysomya megacephala (Fabricius) or mosquito larvae (Aedes aegypti (L.) and Culex quinquefasciatus Say). 2. Adhesive viscosity affected the tackiness of the glues and this determined their trapping efficiency in air or water. 3. From the 'Hyvis' range of adhesives tested, 'Hyvis 200' was most effective for trapping adult flies. 4. With 24 h exposure to fourth instar Ae.aegypti larvae in tapwater, submerged plates coated with 'Hyvis 10', 'Hyvis 30' or 'Hyvis 200' formulations trapped the majority of larvae. In polluted water the highest rates of trapping were 17.3% of Ae.aegypti and 18.7% of Cx quinquefasciatus with 'Hyvis 200'. Floating traps were consistently less productive than submerged traps under laboratory conditions. 5. In a heavily polluted natural breeding-site of Cx quinquefasciatus, floating traps were more productive than submerged sticky traps with four of seven adhesives tested, the most efficient being 'Hyvis 200' (4.2 mosquitoes per hour) and Hyvis:polyethylene 90:10 (4.5/h). Despite the relative inefficiency of aquatic traps, emergent adults, pupae and second to fourth instars of larvae were collected quickly from the habitat. PMID:2979541

  18. Evaluation of some adhesives for collecting Musca domestica and Chrysomya megacephala adults or mosquito larvae in sticky traps.

    PubMed

    Sulaiman, S; Yunus, H; Sohadi, R

    1987-07-01

    1. Seven types of water-insoluble adhesives were evaluated in sticky traps for collecting adults of Musca domestica L. and Chrysomya megacephala (Fabricius) or mosquito larvae (Aedes aegypti (L.) and Culex quinquefasciatus Say). 2. Adhesive viscosity affected the tackiness of the glues and this determined their trapping efficiency in air or water. 3. From the 'Hyvis' range of adhesives tested, 'Hyvis 200' was most effective for trapping adult flies. 4. With 24 h exposure to fourth instar Ae.aegypti larvae in tapwater, submerged plates coated with 'Hyvis 10', 'Hyvis 30' or 'Hyvis 200' formulations trapped the majority of larvae. In polluted water the highest rates of trapping were 17.3% of Ae.aegypti and 18.7% of Cx quinquefasciatus with 'Hyvis 200'. Floating traps were consistently less productive than submerged traps under laboratory conditions. 5. In a heavily polluted natural breeding-site of Cx quinquefasciatus, floating traps were more productive than submerged sticky traps with four of seven adhesives tested, the most efficient being 'Hyvis 200' (4.2 mosquitoes per hour) and Hyvis:polyethylene 90:10 (4.5/h). Despite the relative inefficiency of aquatic traps, emergent adults, pupae and second to fourth instars of larvae were collected quickly from the habitat.

  19. Repellent properties of Cardiospermum halicacabum Linn. (Family: Sapindaceae) plant leaf extracts against three important vector mosquitoes

    PubMed Central

    Govindarajan, M; Sivakumar, R

    2012-01-01

    Objective To determine repellent activity of hexane, ethyl acetate, benzene, chloroform and methanol extract of Cardiospermum halicacabum (C. halicacabum) against Culex quinquefasciatus (Cx. quinquefasciatus), Aedes aegypti (Ae. aegypti) and Anopheles stephensi (An. stephensi). Methods Evaluation was carried out in a net cage (45 cm×30 cm×25 cm) containing 100 blood starved female mosquitoes of three mosquito species and were assayed in the laboratory condition by using the protocol of WHO 2005; The plant leaf crude extracts of C. halicacabum was applied at 1.0, 2.5, and 5.0 mg/cm2 separately in the exposed area of the fore arm. Only ethanol served as control. Results In this observation, the plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person, and also, the repellent activity was dependent on the strength of the plant extracts. The tested plant crude extracts had exerted promising repellent against all the three mosquitoes. Conclusions From the results it can be concluded the crude extract of C. halicacabum was potential for controlling Cx. quinquefasciatus, Ae. aegypti and An. stephensi mosquitoes. PMID:23569979

  20. Implications of saline concentrations for the performance and competitive interactions of the mosquitoes Aedes aegypti (Stegomyia aegypti) and Aedes albopictus (Stegomyia albopictus).

    PubMed

    Yee, D A; Himel, E; Reiskind, M H; Vamosi, S M

    2014-03-01

    Aedes albopictus (Stegomyia albopictus) (Diptera: Culicidae) has probably supplanted Aedes aegypti (Stegomyia aegypti) throughout most of its historical range in the U.S.A., although Ae. aegypti still exists in large coastal cities in southern Florida. We measured salt concentrations in field containers along an axis perpendicular to the coast and examined intraspecific outcomes in these species under different salt concentrations in a factorial study using varying intra- and interspecific densities in different conditions of salinity to order to determine if salt could mitigate the documented competitive superiority of Ae. albopictus. Salt in field containers declined away from the coast, with maximal values similar to our lower salt concentrations. Egg hatching and short-term survival of pupae and late instars were not affected by salt concentrations; survival of early instars of both species decreased at higher concentrations. In high salt conditions, Ae. aegypti achieved higher survival. In the longterm experiment, both species displayed longer development times. Salt did not affect interactions for either species; Ae. aegypti survived in the highest salt conditions, regardless of density. The tolerance of Ae. aegypti to high salt concentrations may allow it to use coastal containers, although because salt did not mediate interspecific interactions between Ae. aegypti and Ae. albopictus, the ultimate effects of salt on the coexistence of these species or exclusion of either species remain unknown. PMID:23607885

  1. Implications of saline concentrations for the performance and competitive interactions of the mosquitoes Aedes aegypti (Stegomyia aegypti) and Aedes albopictus (Stegomyia albopictus).

    PubMed

    Yee, D A; Himel, E; Reiskind, M H; Vamosi, S M

    2014-03-01

    Aedes albopictus (Stegomyia albopictus) (Diptera: Culicidae) has probably supplanted Aedes aegypti (Stegomyia aegypti) throughout most of its historical range in the U.S.A., although Ae. aegypti still exists in large coastal cities in southern Florida. We measured salt concentrations in field containers along an axis perpendicular to the coast and examined intraspecific outcomes in these species under different salt concentrations in a factorial study using varying intra- and interspecific densities in different conditions of salinity to order to determine if salt could mitigate the documented competitive superiority of Ae. albopictus. Salt in field containers declined away from the coast, with maximal values similar to our lower salt concentrations. Egg hatching and short-term survival of pupae and late instars were not affected by salt concentrations; survival of early instars of both species decreased at higher concentrations. In high salt conditions, Ae. aegypti achieved higher survival. In the longterm experiment, both species displayed longer development times. Salt did not affect interactions for either species; Ae. aegypti survived in the highest salt conditions, regardless of density. The tolerance of Ae. aegypti to high salt concentrations may allow it to use coastal containers, although because salt did not mediate interspecific interactions between Ae. aegypti and Ae. albopictus, the ultimate effects of salt on the coexistence of these species or exclusion of either species remain unknown.

  2. EFFICACY OF THAI NEEM OIL AGAINST AEDES AEGYPTI (L.) LARVAE.

    PubMed

    Silapanuntakul, Suthep; Keanjoom, Romnalin; Pandii, Wongdyan; Boonchuen, Supawadee; Sombatsiri, Kwanchai

    2016-05-01

    Trees with larvicidal activity may be found in Thailand. We conducted this study to evaluate the efficacy and length of efficacy of Thai neem (Azadirachta siamensis) oil emulsion and an alginate bead of Thai neem oil formulation against early fourth stage Aedes aegypti larvae using a dipping test. The Thai neem oil emulsion had significantly greater larvicidal activity than the alginate bead formulation at 12 to 60 hours post-exposure (p < 0.01). The Thai neem oil formulation resulted in 100% mortality among the early fourth stage Aedes aegypti larvae at 48 hours, while the alginate bead formulation resulted in 98% larval mortality at 84 hours and 100% mortality at 96 hours. The mean larval mortality using the Thai neem oil emulsion dropped to < 25% by 12 days and with the alginate beads dropped to < 25% by 15 days of exposure.

  3. Identification of germline transcriptional regulatory elements in Aedes aegypti

    NASA Astrophysics Data System (ADS)

    Akbari, Omar S.; Papathanos, Philippos A.; Sandler, Jeremy E.; Kennedy, Katie; Hay, Bruce A.

    2014-02-01

    The mosquito Aedes aegypti is the principal vector for the yellow fever and dengue viruses, and is also responsible for recent outbreaks of the alphavirus chikungunya. Vector control strategies utilizing engineered gene drive systems are being developed as a means of replacing wild, pathogen transmitting mosquitoes with individuals refractory to disease transmission, or bringing about population suppression. Several of these systems, including Medea, UDMEL, and site-specific nucleases, which can be used to drive genes into populations or bring about population suppression, utilize transcriptional regulatory elements that drive germline-specific expression. Here we report the identification of multiple regulatory elements able to drive gene expression specifically in the female germline, or in the male and female germline, in the mosquito Aedes aegypti. These elements can also be used as tools with which to probe the roles of specific genes in germline function and in the early embryo, through overexpression or RNA interference.

  4. Identification of germline transcriptional regulatory elements in Aedes aegypti.

    PubMed

    Akbari, Omar S; Papathanos, Philippos A; Sandler, Jeremy E; Kennedy, Katie; Hay, Bruce A

    2014-02-04

    The mosquito Aedes aegypti is the principal vector for the yellow fever and dengue viruses, and is also responsible for recent outbreaks of the alphavirus chikungunya. Vector control strategies utilizing engineered gene drive systems are being developed as a means of replacing wild, pathogen transmitting mosquitoes with individuals refractory to disease transmission, or bringing about population suppression. Several of these systems, including Medea, UD(MEL), and site-specific nucleases, which can be used to drive genes into populations or bring about population suppression, utilize transcriptional regulatory elements that drive germline-specific expression. Here we report the identification of multiple regulatory elements able to drive gene expression specifically in the female germline, or in the male and female germline, in the mosquito Aedes aegypti. These elements can also be used as tools with which to probe the roles of specific genes in germline function and in the early embryo, through overexpression or RNA interference.

  5. Oviposition and olfaction responses of Aedes aegypti mosquitoes to insecticides.

    PubMed

    Canyon, D V; Muller, R

    2013-12-01

    Insecticide applications are not particularly effective on Aedes aegypti mosquitoes which has been attributed to their 'closet' behaviour, or ability to rest in places that remain unexposed to insecticides. Some researchers have suggested that insecticides repel mosquitoes, which would result in less exposure and increased dispersal. If repellence due to insecticides is a fact, acquiring a vector-borne disease, such as dengue, could legitimately be attributed to local vector control efforts and this would lead to restitution claims. This study thus investigated the effect of insecticide presence on mosquito behaviour indirectly via oviposition and directly via olfactory response. In all experiments, oviposition in each insecticide compared to its water and ethanol controls was not significantly different. This indicates that Ae. aegypti mosquitoes are not affected by insecticide presence and that increased dispersal is unlikely to be caused by vector control spraying.

  6. EFFICACY OF THAI NEEM OIL AGAINST AEDES AEGYPTI (L.) LARVAE.

    PubMed

    Silapanuntakul, Suthep; Keanjoom, Romnalin; Pandii, Wongdyan; Boonchuen, Supawadee; Sombatsiri, Kwanchai

    2016-05-01

    Trees with larvicidal activity may be found in Thailand. We conducted this study to evaluate the efficacy and length of efficacy of Thai neem (Azadirachta siamensis) oil emulsion and an alginate bead of Thai neem oil formulation against early fourth stage Aedes aegypti larvae using a dipping test. The Thai neem oil emulsion had significantly greater larvicidal activity than the alginate bead formulation at 12 to 60 hours post-exposure (p < 0.01). The Thai neem oil formulation resulted in 100% mortality among the early fourth stage Aedes aegypti larvae at 48 hours, while the alginate bead formulation resulted in 98% larval mortality at 84 hours and 100% mortality at 96 hours. The mean larval mortality using the Thai neem oil emulsion dropped to < 25% by 12 days and with the alginate beads dropped to < 25% by 15 days of exposure. PMID:27405123

  7. Toxicity of VectoLex (Bacillus sphaericus) products to selected Australian mosquito and nontarget species.

    PubMed

    Brown, I D; Watson, T M; Carter, J; Purdie, D M; Kay, B H

    2004-02-01

    Laboratory and field bioassay studies were conducted in southeast Queensland, Australia, on the efficacy of VectoLex Control Granule (CG; active ingredient [AI]:50 Bacillus sphaericus [B.s.] International Toxic Units [ITU]/mg) and VectoLex Water Dispersible Granule (WDG) (AI: 650 B.s. ITU/mg) formulations against third-instar larvae of Culex annulirostris Skuse, Culex quinquefasciatus Say, Culex sitiens Wiedemann, Ochlerotatus rigilax (Skuse), Ochlerotatus. notoscriptus (Skuse), and Aedes aegypti (L.). The Gompertz model for log-linear mortality data were used to determine laboratory 48-h LC95 values. As with foreign evaluations, the B.s. formulations were most effective against Culex spp., with the WDG 10-100 times more effective than the CG on an ITU/mosquito basis. Consequently, Cx. annulirostris and Cx. quinquefasciatus were selected as target species for small-plot field evaluation of WDG efficacy over time. Weekly cohorts of caged third-instar Cx. annulirostris were exposed to replicated low (250 g/ha), medium (500 g/ha), and high (1,000 g/ha) dosages of WDG. Concurrent assessment of Cx. quinquefasciatus mortality outside the cages was also conducted. In water with high organic content, the low rate produced > 99% Cx. annulirostris mortality at 48 h, decreasing to 79% at week 3 and no control at week 4. The medium and high rates resulted in 100% Cx. annulirostris mortality for 2 wk posttreatment, decreasing to 95% at week 3, and no control at week 4. The WDG was equally effective against Cx. quinquefasciatus. Treatment did not affect water quality or nontarget shrimp and fish species survival.

  8. Understanding productivity, a key to Aedes aegypti surveillance.

    PubMed

    Tun-Lin, W; Kay, B H; Barnes, A

    1995-12-01

    The objective of this work was to define criteria that could be applied to achieve faster, more economical, and accurate assessment of vector populations for control of dengue viruses. During 1989-1990, 1,349 premises were surveyed in Townsville, Charters Towers and Mingela/Ravenswood, Queensland, Australia. In each locality, 1.9-8.4% of premises contained three or more containers with Aedes aegypti immature forms and were designated as key premises. Comparison of surveys in Townsville from 1989 to 1990 indicated that positive premises (i.e., those with at least one container with Ae. aegypti present) were 3.22 times more likely to remain positive than negative houses to become positive the following year. The Ae. aegypti population in Townsville was seen to be totally associated with garden receptacles, discarded household items, and trash but one well and one rainwater tank were responsible for 28% of all immature forms recorded in the 1,349 premises inspected. These breeding sites of high productivity were designated as key containers. At Charters Towers, Mingela, and Ravenswood, rainwater tanks were seen as the most important key container because although they constituted 13-29% of positive containers, they supported 60-63% of the immature forms. This study demonstrates that there is a certain degree of stability with regard to positive premises and that some of these, or some container types, contribute disproportionately to the Ae. aegypti population. Control programs could be made more efficient if efforts were concentrated on these sites of key vector productivity.

  9. Intraspecific Competition and Population Dynamics of Aedes aegypti

    NASA Astrophysics Data System (ADS)

    Paixão, C. A.; Charret, I. C.; Lima, R. R.

    2012-04-01

    We report computational simulations for the evolution of the population of the dengue vector, Aedes aegypti mosquitoes. The results suggest that controlling the mosquito population, on the basis of intraspecific competition at the larval stage, can be an efficient mechanism for controlling the spread of the epidemic. The results also show the presence of a kind of genetic evolution in vector population, which results mainly in increasing the average lifespan of individuals in adulthood.

  10. Similarity solutions for systems arising from an Aedes aegypti model

    NASA Astrophysics Data System (ADS)

    Freire, Igor Leite; Torrisi, Mariano

    2014-04-01

    In a recent paper a new model for the Aedes aegypti mosquito dispersal dynamics was proposed and its Lie point symmetries were investigated. According to the carried group classification, the maximal symmetry Lie algebra of the nonlinear cases is reached whenever the advection term vanishes. In this work we analyze the family of systems obtained when the wind effects on the proposed model are neglected. Wide new classes of solutions to the systems under consideration are obtained.

  11. Macroclimate determines the global range limit of Aedes aegypti.

    PubMed

    Capinha, César; Rocha, Jorge; Sousa, Carla A

    2014-09-01

    Aedes aegypti is the main vector of dengue and a number of other diseases worldwide. Because of the domestic nature of this mosquito, the relative importance of macroclimate in shaping its distribution has been a controversial issue. We have captured here the worldwide macroclimatic conditions occupied by A. aegypti in the last century. We assessed the ability of this information to predict the species' observed distribution using supra-continental spatially-uncorrelated data. We further projected the distribution of the colonized climates in the near future (2010-2039) under two climate-change scenarios. Our results indicate that the macroclimate is largely responsible for setting the maximum range limit of A. aegypti worldwide and that in the near future, relatively wide areas beyond this limit will receive macroclimates previously occupied by the species. By comparing our projections, with those from a previous model based strictly on species-climate relationships (i.e., excluding human influence), we also found support for the hypothesis that much of the species' range in temperate and subtropical regions is being sustained by artificial environments. Altogether, these findings suggest that, if the domestic environments commonly exploited by this species are available in the newly suitable areas, its distribution may expand considerably in the near future. PMID:24643859

  12. Germline excision of transgenes in Aedes aegypti by homing endonucleases.

    PubMed

    Aryan, Azadeh; Anderson, Michelle A E; Myles, Kevin M; Adelman, Zach N

    2013-01-01

    Aedes (Ae.) aegypti is the primary vector for dengue viruses (serotypes1-4) and chikungunya virus. Homing endonucleases (HEs) are ancient selfish elements that catalyze double-stranded DNA breaks (DSB) in a highly specific manner. In this report, we show that the HEs Y2-I-AniI, I-CreI and I-SceI are all capable of catalyzing the excision of genomic segments from the Ae. aegypti genome in a heritable manner. Y2-I-AniI demonstrated the highest efficiency at two independent genomic targets, with 20-40% of Y2-I-AniI-treated individuals producing offspring that had lost the target transgene. HE-induced DSBs were found to be repaired via the single-strand annealing (SSA) and non-homologous end-joining (NHEJ) pathways in a manner dependent on the availability of direct repeat sequences in the transgene. These results support the development of HE-based gene editing and gene drive strategies in Ae. aegypti, and confirm the utility of HEs in the manipulation and modification of transgenes in this important vector.

  13. Formulas of components of citronella oil against mosquitoes (Aedes aegypti).

    PubMed

    Hsu, Wey-Shin; Yen, Jui-Hung; Wang, Yei-Shung

    2013-01-01

    The mosquito Aedes aegypti is an epidemic vector of several diseases such as dengue fever and yellow fever. Several pesticides are used to control the mosquito population. Because of their frequent use, some mosquitoes have developed resistance. In this study, we used the Y-tube olfactometer to test essential oils of Cymbopogon species and screened specific formulas of components as repellents against Ae. aegypti. At 400 μL, the extracted oil of citronella grass (Cymbopogon nardus) and myrcene produced a low-active response by inhibiting mosquito host-seeking activity. Citronella grass, lemon grass (Cymbopogon citratus), citral and myrcene also produced a low-treatment response to repellents, for more potential to affect host-seeking behavior. Furthermore, the mixture of citral, myrcene, and citronellal oil (C:M:Ci = 6:4:1) greatly affected and inhibited host-seeking behavior (76% active response; 26% treatment response with 40 μL; 42.5%, 18% with 400 μL; and 19%, 23% with 1000 μL). As compared with the result for N,N-diethyl-3-methylbenzamide (DEET; 44%, 22% with 400 μL), adjusting the composition formulas of citronella oil had a synergistic effect, for more effective repellent against Ae. aegypti. PMID:23998314

  14. New Candidates for Plant-Based Repellents Against Aedes aegypti.

    PubMed

    Misni, Norashiqin; Nor, Zurainee Mohamed; Ahmad, Rohani

    2016-06-01

    Based on an ethnobotanical study on use for plant species against mosquito bites in the Kota Tinggi District, Johor State, Malaysia, 3 plants selected for study, Citrus aurantifolia (leaves), Citrus grandis (fruit peel), and Alpinia galanga (rhizome), were extracted using hydrodistillation to produce essential oils. These essential oils were then formulated as a lotion using a microencapsulation process and then tested for their repellent effect against Aedes aegypti. N,N-diethyl-m-toluamide (deet) was also prepared in the same formulation and tested for repellency as controls. Four commercial plant-based repellent (KAPS(®), MozAway(®), BioZ Natural(®), and Mosiquard(®)) also were incorporated in the bioassay for comparison purposes. Bioassays revealed that at 20% concentration all repellent formulations demonstrated complete protection for 2 h and >90% for 4 h post-application. The A. galanga-based formulation provided the greatest level of protection (98.91%), which extended for 4 h post-application and was not significantly different from deet at similar concentration. When compared with commercial plant-based repellents (KAPS(®), MozAway(®), and BioZ Natural(®)), the 3 lotion formulations showed significantly better protection against Ae. aegypti bites, providing >90% protection for 4 h. In conclusion, our 3 plant-based lotion formulations provided acceptable levels of protection against host-seeking Ae. aegypti and should be developed.

  15. New Candidates for Plant-Based Repellents Against Aedes aegypti.

    PubMed

    Misni, Norashiqin; Nor, Zurainee Mohamed; Ahmad, Rohani

    2016-06-01

    Based on an ethnobotanical study on use for plant species against mosquito bites in the Kota Tinggi District, Johor State, Malaysia, 3 plants selected for study, Citrus aurantifolia (leaves), Citrus grandis (fruit peel), and Alpinia galanga (rhizome), were extracted using hydrodistillation to produce essential oils. These essential oils were then formulated as a lotion using a microencapsulation process and then tested for their repellent effect against Aedes aegypti. N,N-diethyl-m-toluamide (deet) was also prepared in the same formulation and tested for repellency as controls. Four commercial plant-based repellent (KAPS(®), MozAway(®), BioZ Natural(®), and Mosiquard(®)) also were incorporated in the bioassay for comparison purposes. Bioassays revealed that at 20% concentration all repellent formulations demonstrated complete protection for 2 h and >90% for 4 h post-application. The A. galanga-based formulation provided the greatest level of protection (98.91%), which extended for 4 h post-application and was not significantly different from deet at similar concentration. When compared with commercial plant-based repellents (KAPS(®), MozAway(®), and BioZ Natural(®)), the 3 lotion formulations showed significantly better protection against Ae. aegypti bites, providing >90% protection for 4 h. In conclusion, our 3 plant-based lotion formulations provided acceptable levels of protection against host-seeking Ae. aegypti and should be developed. PMID:27280349

  16. [Anti-Aedes aegypti campaign in French Guiana].

    PubMed

    Cebret, A; Désiré, R

    1996-01-01

    The history of vector control in French Guiana started in 1947 when a small team was recruited for that purpose. In 1949, the first DDT treatments were implemented and Aedes aegypti could not be found until 1960. Between 1966 and 1972 an eradication campaign was carried out which resulted in the elimination of Ae. aegypti from all the department except the city of Cayenne. Malathion and orthodibrom were used as adulticides and temephos (Abate) was sprayed against the larvae. Nevertheless, in 1980, Ae. aegypti was still infesting Cayenne and its surroundings. The pilot project of the "Cité Grant" was developed, but never gave the expected results. In 1986, the vector control agency called "Service départmental de désinfection" was restructured and extended. During the 1990s, collaborations were developed between the different health participants of French Guiana, to improve disease control. Actually, the vector control activities include house inspections, mainly to detect, treat or eliminate the breeding-sources, and also to set up entomological indices. Furthermore, investigations are made on the laboratory confirmed dengue cases to find and treat the place of infection, spatial sprayings are made against the adults, and the community health education has being reinforced. The situation in French Guiana is not optimistic for climatic and logistical reasons, and the lack of participation from the community. The perspectives are to improve vector control through education, collaborations with local authorities, reorganisation of the control teams and regional exchanges.

  17. Imidacloprid impairs the post-embryonic development of the midgut in the yellow fever mosquito Stegomyia aegypti (=Aedes aegypti).

    PubMed

    Fernandes, K M; Gonzaga, W G; Pascini, T V; Miranda, F R; Tomé, H V V; Serrão, J E; Martins, G F

    2015-09-01

    The mosquito Stegomyia aegypti (=Aedes aegypti) (Diptera: Culicidae) is a vector for the dengue and yellow fever viruses. As blood digestion occurs in the midgut, this organ constitutes the route of entry of many pathogens. The effects of the insecticide imidacloprid on the survival of St. aegypti were investigated and the sub-lethal effects of the insecticide on midgut development were determined. Third instar larvae were exposed to different concentrations of imidacloprid (0.15, 1.5, 3.0, 6.0 and 15.0 p.p.m.) and survival was monitored every 24 h for 10 days. Midguts from imidacloprid-treated insects at different stages of development were dissected and processed for analyses by transmission electron microscopy, immunofluorescence microscopy and terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) assays. Imidacloprid concentrations of 3.0 and 15.0 p.p.m. were found to affect midgut development similarly. Digestive cells of the fourth instar larvae (L4) midgut exposed to imidacloprid had more multilamellar bodies, abundantly found in the cell apex, and more electron-lucent vacuoles in the basal region compared with those from untreated insects. Moreover, imidacloprid interfered with the differentiation of regenerative cells, dramatically reducing the number of digestive and endocrine cells and leading to malformation of the midgut epithelium in adults. The data demonstrate that imidacloprid can reduce the survival of mosquitoes and thus indicate its potentially high efficacy in the control of St. aegypti populations.

  18. Multiple factors contribute to anautogenous reproduction by the mosquito Aedes aegypti.

    PubMed

    Gulia-Nuss, Monika; Elliot, Anne; Brown, Mark R; Strand, Michael R

    2015-11-01

    Aedes aegypti is an anautogenous mosquito that must blood feed on a vertebrate host to produce and lay a clutch of eggs. The rockpool mosquito, Georgecraigius atropalpus, is related to A. aegypti but is a facultatively autogenous species that produces its first clutch of eggs shortly after emerging without blood feeding. Consumption of a blood meal by A. aegypti triggers the release of ovary ecdysteroidogenic hormone (OEH) and insulin-like peptide 3 (ILP3) from the brain, which stimulate egg formation. OEH and ILP3 also stimulate egg formation in G. atropalpus but are released at eclosion independently of blood feeding. These results collectively suggest that blood meal dependent release of OEH and ILP3 is one factor that prevents A. aegypti from reproducing autogenously. Here, we examined two other factors that potentially inhibit autogeny in A. aegypti: teneral nutrient reserves and the ability of OEH and ILP3 to stimulate egg formation in the absence of blood feeding. Measures of nutrient reserves showed that newly emerged A. aegypti females had similar wet weights but significantly lower protein and glycogen reserves than G. atropalpus females when larvae were reared under identical conditions. OEH stimulated non-blood fed A. aegypti females to produce ecdysteroid hormone and package yolk into oocytes more strongly than ILP3. OEH also reduced host seeking and blood feeding behavior, yet females produced few mature eggs. Overall, our results indicate that multiple factors prevent A. aegypti from reproducing autogenously.

  19. Occurrence of Toxorhynchites guadeloupensis (Dyar Knab) in oviposition trap of Aedes aegypti (L.) (Diptera: Culicidae).

    PubMed

    Honório, Nildimar A; de Barros, Fábio S M; Tsouris, Pantelis; Rosa-Freitas, Maria G

    2007-01-01

    Toxorhynchites guadeloupensis (Dyar Knab), a poorly known mosquito species, was observed preying upon Aedes aegypti (L.) larvae, in an oviposition trap placed for routine dengue entomological surveillance, during 2003-2004 in the urban area of Boa Vista, Roraima, Brazil. This is the first report for Tx. guadeloupensis using Ae. aegypti oviposition traps as breeding places. T