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Sample records for culex pipiens aedes

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

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

    2002-09-01

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

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

    OpenAIRE

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

    2009-01-01

    Copepods from La Plata, Argentina were investigated to characterize the local community of larvivorous copepods inhabiting mosquito breeding sites and to identify new predator species of the mosquitoes which occur in artificial containers, Aedes aegypti and Culex pipiens. Diversity of larvivorous cyclopoids was highest in permanent pools. Predation by sex and age, selectivity on mosquito species, and daily predation rate during five days were studied for Acanthocyclops robustus, Diacyclops ur...

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

    OpenAIRE

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

    2008-01-01

    Copepods from La Plata, Argentina were investigated to characterize the local community of larvivorous copepods inhabiting mosquito breeding sites and to identify new predator species of the mosquitoes which occur in artificial containers, Aedes aegypti and Culex pipiens. Diversity of larvivorous cyclopoids was highest in permanent pools. Predation by sex and age, selectivity on mosquito species, and daily predation rate during five days were studied for Acanthocyclops robustus, Diacyclops ur...

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

    Science.gov (United States)

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

    2009-12-01

    Copepods from La Plata, Argentina were investigated to characterize the local community of larvivorous copepods inhabiting mosquito breeding sites and to identify new predator species of the mosquitoes which occur in artificial containers, Aedes aegypti and Culex pipiens. Diversity of larvivorous cyclopoids was highest in permanent pools. Predation by sex and age, selectivity on mosquito species, and daily predation rate during five days were studied for Acanthocyclops robustus, Diacyclops uruguayensis, Macrocyclops albidus and Mesocyclops longisetus. Female copepods presented the highest predatory capacity. No predatory preference for mosquito species was found. According to overall predation potential, copepods were ranked as follows: D. uruguayensis biological control agents for mosquitoes.

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

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    Desprès, Philippe

    2017-01-01

    Background Japanese encephalitis virus (JEV) is the causative agent of Japanese encephalitis, the leading cause of viral encephalitis in Asia. JEV transmission cycle involves mosquitoes and vertebrate hosts. The detection of JEV RNA in a pool of Culex pipiens caught in 2010 in Italy raised the concern of a putative emergence of the virus in Europe. We aimed to study the vector competence of European mosquito populations, such as Cx. pipiens and Aedes albopictus for JEV genotypes 3 and 5. Findings After oral feeding on an infectious blood meal, mosquitoes were dissected at various times post-virus exposure. We found that the peak for JEV infection and transmission was between 11 and 13 days post-virus exposure. We observed a faster dissemination of both JEV genotypes in Ae. albopictus mosquitoes, when compared with Cx. pipiens mosquitoes. We also dissected salivary glands and collected saliva from infected mosquitoes and showed that Ae. albopictus mosquitoes transmitted JEV earlier than Cx. pipiens. The virus collected from Ae. albopictus and Cx. pipiens saliva was competent at causing pathogenesis in a mouse model for JEV infection. Using this model, we found that mosquito saliva or salivary glands did not enhance the severity of the disease. Conclusions In this study, we demonstrated that European populations of Ae. albopictus and Cx. pipiens were efficient vectors for JEV transmission. Susceptible vertebrate species that develop high viremia are an obligatory part of the JEV transmission cycle. This study highlights the need to investigate the susceptibility of potential JEV reservoir hosts in Europe, notably amongst swine populations and local water birds. PMID:28085881

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

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

    2017-01-01

    Japanese encephalitis virus (JEV) is the causative agent of Japanese encephalitis, the leading cause of viral encephalitis in Asia. JEV transmission cycle involves mosquitoes and vertebrate hosts. The detection of JEV RNA in a pool of Culex pipiens caught in 2010 in Italy raised the concern of a putative emergence of the virus in Europe. We aimed to study the vector competence of European mosquito populations, such as Cx. pipiens and Aedes albopictus for JEV genotypes 3 and 5. After oral feeding on an infectious blood meal, mosquitoes were dissected at various times post-virus exposure. We found that the peak for JEV infection and transmission was between 11 and 13 days post-virus exposure. We observed a faster dissemination of both JEV genotypes in Ae. albopictus mosquitoes, when compared with Cx. pipiens mosquitoes. We also dissected salivary glands and collected saliva from infected mosquitoes and showed that Ae. albopictus mosquitoes transmitted JEV earlier than Cx. pipiens. The virus collected from Ae. albopictus and Cx. pipiens saliva was competent at causing pathogenesis in a mouse model for JEV infection. Using this model, we found that mosquito saliva or salivary glands did not enhance the severity of the disease. In this study, we demonstrated that European populations of Ae. albopictus and Cx. pipiens were efficient vectors for JEV transmission. Susceptible vertebrate species that develop high viremia are an obligatory part of the JEV transmission cycle. This study highlights the need to investigate the susceptibility of potential JEV reservoir hosts in Europe, notably amongst swine populations and local water birds.

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

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    Amrul Munif

    2012-09-01

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

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

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    María C Tranchida

    2009-12-01

    Full Text Available Copepods from La Plata, Argentina were investigated to characterize the local community of larvivorous copepods inhabiting mosquito breeding sites and to identify new predator species of the mosquitoes which occur in artificial containers, Aedes aegypti and Culex pipiens. Diversity of larvivorous cyclopoids was highest in permanent pools. Predation by sex and age, selectivity on mosquito species, and daily predation rate during five days were studied for Acanthocyclops robustus, Diacyclops uruguayensis, Macrocyclops albidus and Mesocyclops longisetus. Female copepods presented the highest predatory capacity. No predatory preference for mosquito species was found. According to overall predation potential, copepods were ranked as follows: D. uruguayensis Se hizo una prospección de copépodos en La Plata, Argentina, con los objetivos de caracterizar la comunidad local de copépodos larvívoros en sitios de cría de mosquitos, e identificar nuevas especies depredadoras de los mosquitos de contenedores artificiales Aedes aegypti y Culex pipiens. La diversidad de ciclopoides larvívoros fue máxima en charcos permanentes. Se examinó la depredación por sexos y edad, la selectividad por especies de mosquito, y la tasa de depredación diaria durante cinco días en Acanthocyclops robustus, Diacyclops uruguayensis, Macrocyclops albidus y Mesocyclops longisetus. Los copépodos hembra presentaron la capacidad depredadora más alta. No se encontró preferencia por alguna especie de mosquito. De acuerdo al potencial de depredación en general, los copépodos se ordenan así: D. uruguayensis < A. robustus < M. albidus < M. longisetus. También se evaluó la tolerancia a la desecación del hábitat y la capacidad de resistir en agua de contenedores artificiales. D. uruguayensis y A. robustus sobrevivieron en condiciones de sequía, pero D. uruguayensis presentó menor supervivencia en agua de floreros de cementerio. M. albidus no sobrevivió condiciones de

  9. Macrocyclops albidus (Copepoda: cyclopidae) for the Biocontrol of Aedes albopictus and Culex pipiens in Italy.

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    Veronesi, Rodolfo; Carrieri, Marco; Maccagnani, Bettina; Maini, Stefano; Bellini, Romeo

    2015-03-01

    The aim of our study was to assess the potential of Macrocyclops albidus as a biological control agent against the 1st and 2nd instars of Culex pipiens and Aedes albopictus. Under laboratory conditions of prey saturation (50 1st instars/copepod), an average of 58.98% of Cx. pipiens and 54.99% of Ae. albopictus larvae were killed by 1 copepod in 24 h. Trials run in big drums containing 200 liters of water showed that the M. albidus population, inoculated in April, efficiently controlled the mosquito population for the entire season. The predator was particularly effective against Ae. albopictus, as only 2 larvae of this species were found in the treated drums, compared to 814 larvae in untreated control drums throughout the study period. No difference was observed in the control efficacy between the 2 initial densities of copepods used. The reduction in Ae. albopictus density in the drums with 100 and 500 M. albidus with respect to the control drums was 99.90 ± 0.35% and 100.0 ± 0.0%, respectively. For Cx. pipiens, the reduction in density was 88.69 ± 13.51% and 84.65% in drums inoculated with 100 and 500 copepods, respectively. Macrocyclops albidus populations survived through the winter and continued to keep the mosquito population under control during the 2008 season. The M. albidus population developed very well both in drums placed in sunny and shaded areas and proved to be tolerant to both high (summer) and low (winter) temperatures. Trials performed on M. albidus survival in catch basins showed that after a few weeks, the copepod population dramatically decreased and subsequently disappeared. The main problem for copepod survival in catch basins seemed to be the low oxygen tension and accumulation of toxic substances, rather than copepods being flushed out in heavy rainfall episodes. During the period when copepods were present, they maintained the mosquito population under control; their partial disappearance from the catch basins, however, would

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

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    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/♀.

  11. Efectos de la competencia larval en los mosquitos de contenedores artificiales, Aedes aegypti y Culex pipiens (Diptera: Culicidae en condiciones semi-controladas

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    Analía FRANCIA

    2011-01-01

    Full Text Available Las larvas de los mosquitos Aedes aegypti (Linneo y Culex pipiens Linneo pueden criar conjuntamente en pequeños contenedores artificiales de agua, se genera así una competencia interespecífica y/o intraespecífica. El objetivo de este trabajo fue comparar la magnitud relativa de la competencia intra e interespecífica en A. aegypti y C. pipiens, generada durante el desarrollo larval en contenedores artificiales. Las variables medidas como respuesta fueron la supervivencia y el tiempo de desarrollo larval, y la biomasa total producida en estado de pupa. Se criaron larvas de ambos mosquitos en neumáticos de automóvil con agua declorinada y hojarasca. Se introdujeron larvas recién eclosionadas de acuerdo a la densidad (δ estimada según un censo previo de A. aegypti y C. pipiens. Se realizaron los siguientes tratamientos agregando larvas de: (1 A. aegypti hasta alcanzar δ A. aegypti determinada según el censo previo, (2 C. pipiens hasta δ C. pipiens del censo previo, (3 A. aegypti hasta alcanzar la suma de δ A. aegypti y δ C. pipiens del censo previo, (4 C. pipiens hasta alcanzar la suma de δ A. aegypti y δ C. pipiens del censo previo y (5 A. aegypti y C. pipiens hasta δ A. aegypti y δ C. pipiens del censo previo. Las tres variables medidas fueron afectadas por los tratamientos, excepto la supervivencia y la biomasa producida por C. pipiens. Aedes aegypti fue más alterada por la competencia intraespecífica que por la competencia interespecífica. En C. pipiens, la competencia interespecífica superó en sus efectos a la competencia intraespecífica. Existió asimetría competitiva, ya que C. pipiens fue más afectada por A. aegypti que lo contrario.

  12. Efectos de la competencia larval en los mosquitos de contenedores artificiales, Aedes aegypti y Culex pipiens (Diptera: Culicidae en condiciones semi-controladas Effects of larval competition between the container mosquitoes, Aedes aegypti and Culex pipiens (Diptera: Culicidae in semi-controlled conditions

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    Analía Francia

    2011-12-01

    Full Text Available Las larvas de los mosquitos Aedes aegypti (Linneo y Culex pipiens Linneo pueden criar conjuntamente en pequeños contenedores artificiales de agua, se genera así una competencia interespecífica y/o intraespecífica. El objetivo de este trabajo fue comparar la magnitud relativa de la competencia intra e interespecífica en A. aegypti y C. pipiens, generada durante el desarrollo larval en contenedores artifi ciales. Las variables medidas como respuesta fueron la supervivencia y el tiempo de desarrollo larval, y la biomasa total producida en estado de pupa. Se criaron larvas de ambos mosquitos en neumáticos de automóvil con agua declorinada y hojarasca. Se introdujeron larvas recién eclosionadas de acuerdo a la densidad (5 estimada según un censo previo de A. aegypti y C. pipiens. Serealizaron los siguientes tratamientos agregando larvas de: (1 A. aegypti hasta alcanzar δ A. aegypti determinada según el censo previo, (2 C. pipiens hasta δ C. pipiens del censo previo, (3 A. aegypti hasta alcanzar la suma de δ A. aegypti y δ C. pipiens del censo previo, (4 C. pipiens hasta alcanzar la suma de δ A. aegypti y δ C. pipiens del censo previo y (5 A. aegypti y C. pipiens hasta δ A. aegypti y δ C. pipiens del censo previo. Las tres variables medidas fueron afectadas por los tratamientos, excepto la supervivencia y la biomasa producida por C. pipiens. Aedes aegypti fue más alterada por la competencia intraespecífica que por la competencia interespecífica. En C. pipiens, la competencia interespecífica superó en sus efectos a la competencia intraespecífica. Existió asimetría competitiva, ya que C. pipiens fue más afectada por A. aegypti que lo contrario.Larvae of Aedes aegypti (Linneo and Culex pipiens Linneo may develop together in small artificial water containers, promoting inter- and/or intra-specific competition. Our aim was to compare the relative importance of interspecific and intraspecific competition in both species during

  13. The effect of shade on the container index and pupal productivity of the mosquitoes Aedes aegypti and Culex pipiens breeding in artificial containers.

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    Vezzani, D; Albicócco, A P

    2009-03-01

    The aim of this study was to assess whether certain attributes of larval breeding sites are correlated with pupal productivity (i.e. numbers of pupae collected per sampling period), so that these could be used as the focus for control measures to enhance control efficiency. Therefore, the objectives were to identify the months of highest pupal productivity of Aedes aegypti (L.) and Culex pipiens L. (Diptera: Culicidae) in an urban temperate cemetery in Argentina where artificial containers of containers and to determine whether the composition of the containers affected pupal productivity. Over a period of 9 months, 200 randomly chosen water-filled containers (100 sunlit and 100 shaded), out of approximately 3738 containers present (approximately 54% in shade), were examined each month within a cemetery (5 ha) in Buenos Aires (October 2006 to June 2007). In total, 3440 immatures of Cx pipiens and 1974 of Ae. aegypti were collected. The larvae : pupae ratio was 10 times greater for the former, indicating that larval mortality was greater for Cx pipiens. Both mosquito species showed a higher container index (CI) in shaded than in sunlit containers (Ae. aegypti: 12.8% vs. 6.9% [chi(2) = 17.6, P container and the number of pupae per pupa-positive container did not differ significantly between sunlit and shaded containers for either species. Therefore, the overall relative productivity of pupae per ha of Ae. aegypti and Cx pipiens was 2.3 and 1.8 times greater, respectively, in shaded than in sunlit areas as a result of the greater CIs of containers in shaded areas. Neither the CI nor the number of immatures per infested container differed significantly among container types of different materials in either lighting condition. The maximum CI and total pupal counts occurred in March for Ae. aegypti and in January and February for Cx pipiens. The estimated peak abundance of pupae in the whole cemetery reached a total of approximately 4388 in the middle of March for Ae

  14. Predicting distribution of Aedes aegypti and Culex pipiens complex, potential vectors of Rift Valley fever virus in relation to disease epidemics in East Africa

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    Clement Nyamunura Mweya

    2013-10-01

    Full Text Available Background: The East African region has experienced several Rift Valley fever (RVF outbreaks since the 1930s. The objective of this study was to identify distributions of potential disease vectors in relation to disease epidemics. Understanding disease vector potential distributions is a major concern for disease transmission dynamics. Methods: Diverse ecological niche modelling techniques have been developed for this purpose: we present a maximum entropy (Maxent approach for estimating distributions of potential RVF vectors in un-sampled areas in East Africa. We modelled the distribution of two species of mosquitoes (Aedes aegypti and Culex pipiens complex responsible for potential maintenance and amplification of the virus, respectively. Predicted distributions of environmentally suitable areas in East Africa were based on the presence-only occurrence data derived from our entomological study in Ngorongoro District in northern Tanzania. Results: Our model predicted potential suitable areas with high success rates of 90.9% for A. aegypti and 91.6% for C. pipiens complex. Model performance was statistically significantly better than random for both species. Most suitable sites for the two vectors were predicted in central and northwestern Tanzania with previous disease epidemics. Other important risk areas include western Lake Victoria, northern parts of Lake Malawi, and the Rift Valley region of Kenya. Conclusion: Findings from this study show distributions of vectors had biological and epidemiological significance in relation to disease outbreak hotspots, and hence provide guidance for the selection of sampling areas for RVF vectors during inter-epidemic periods.

  15. Controlling Aedes albopictus and Culex pipiens pallens using silver nanoparticles synthesized from aqueous extract of Cassia fistula fruit pulp and its mode of action.

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    Fouad, Hatem; Hongjie, Li; Hosni, Dawood; Wei, Jiqian; Abbas, Ghulam; Ga'al, Hassan; Jianchu, Mo

    2017-05-25

    Mosquitoes act as key vector for transmission of devastating parasites and pathogens which affect millions of people globally. In this research, the green synthesis of silver nanoparticles of Cassia fistula fruit pulp as an innovative and operative tool against vector mosquitoes is presented. Silver nanoparticles were characterized by a series of techniques including Fourier transform infrared spectroscopy, Transmission Electron Microscope and confirmed by Scanning Electron Microscope, UV-Vis spectrophotometry and X-ray diffraction. Silver nanoparticles were highly effective against the larvae (I-IV instar) and pupae of Aedes albopictus and Culex pipiens pallens after 24, 48 and 72 h of treatment. Ae. albopictus had LC50 values ranging from 8.3 mg/L (I instar) to 17.3 mg/L (pupae) and LC50 ranging from 1.1 mg/L (I instar) to 19.0 mg/L (pupae) against Cx. pipiens pallens. The systemic effect of AgNPs was further assessed in the fourth instar larvae of Ae. albopictus and Cx. pipiens pallens by measuring the levels of total proteins and activity of two important marker enzymes: Acetylcholinesterase and α- and β-carboxylesterase. Overall, the findings of the study suggest that the use of Cassia fistula-fruit pulp extract mediated synthesis of silver nanoparticles can be used for controlling vector mosquitoes. This is the first report on the mosquito larvicidal and pupicidal activity of AgNPs synthesized by Cassia fistula fruit pulp and its possible mechanism of action.

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

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    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.

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

    Science.gov (United States)

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

    2016-01-01

    We investigated the susceptibility of an Italian population of Culex pipiens mosquitoes to Zika virus (ZIKV) infection, tested in parallel with Aedes aegypti, as a positive control. We analysed mosquitoes at 0, 3, 7, 10, 14, 20 and 24 days after an infectious blood meal. Viral RNA was detected in the body of Cx. pipiens up to three days post-infection, but not at later time points. Our results indicate that Cx. pipiens is not susceptible to ZIKV infection. PMID:27605056

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

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    Diaz-Perez Alfonso

    2011-05-01

    Full Text Available Abstract Background Culex spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV detected in at least 34 species of mosquitoes in the United States. In North America, Culex pipiens pipiens, Culex pipiens quinquefasciatus, and Culex tarsalis are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of Culex pipiens complex mosquitoes and hybrids in Mexico City. Culex pipiens pipiens preferentially feed on avian hosts; Culex pipiens quinquefasciatus have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of Culex pipiens complex mosquitoes and their hybrids. Results Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as Culex, Culiseta or Ochlerotatus by morphological analysis. Within the genus Culex, specimens were further identified as Culex tarsalis or as belonging to the Culex pipiens complex. Members of the Culex pipiens complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio of the male genitalia and also by using diagnostic primers designed for the Ace.2 gene. Culex pipiens quinquefasciatus was the most abundant form collected. Conclusions Important WNV vectors species, Cx. p. pipiens, Cx. p. quinquefasciatus and Cx. tarsalis, are all present in Mexico City. Hybrids of Cx. p. pipiens and Cx. p

  19. 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

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    Young-Joon Ahn

    2013-05-01

    Full Text Available 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.

  20. 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.

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    Lee, Dong Chan; Ahn, Young-Joon

    2013-05-30

    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.

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

    Science.gov (United States)

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

    2016-09-07

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

  2. Evaluation préliminaire de l'activité larvicide des extraits aqueux des feuilles du ricin (Ricinus communis L. et du bois de thuya (Tetraclinis articulata (Vahl Mast. sur les larves de quatre moustiques culicidés : Culex pipiens (Linné, Aedes caspius (Pallas, Culiseta longiareolata (Aitken et Anopheles maculipennis (Meigen

    Directory of Open Access Journals (Sweden)

    Mahari S.

    2006-01-01

    Full Text Available Preliminary evaluation of larvicidal activity of aqueous extracts from leaves of Ricinus communis L. and from wood of Tetraclinis articulata (Vahl Mast. on the larvae of four mosquito species: Culex pipiens (Linné, Aedes caspius (Pallas, Culiseta longiareolata (Aitken and Anopheles maculipennis (Meigen. Aqueous extracts of Ricinus communis leaves and Tetraclinis articulata wood showed strong toxic activity against larvae of several mosquitoes. In this study, insecticide effects of these plant extracts have been investigated on 2nd and 4th instars larvae of Culicidae insects, Culex pipiens (Linné, Aedes caspius (Pallas, Culiseta longiareolata (Aitken and Anopheles maculipennis (Meigen. After 24 hours of exposition, bioassays revealed low lethal concentrations LC50. To control mosquitoes, these plant extracts might be used as natural biocides.

  3. Evaluation préliminaire de l'activité larvicide des extraits aqueux des feuilles du ricin (Ricinus communis L.) et du bois de thuya (Tetraclinis articulata (Vahl) Mast.) sur les larves de quatre moustiques culicidés : Culex pipiens (Linné), Aedes caspius (Pallas), Culiseta longiareolata (Aitken) et Anopheles maculipennis (Meigen)

    OpenAIRE

    Mahari S.; Mellouki F.; Oufara S.; Aouinty B.

    2006-01-01

    Preliminary evaluation of larvicidal activity of aqueous extracts from leaves of Ricinus communis L. and from wood of Tetraclinis articulata (Vahl) Mast. on the larvae of four mosquito species: Culex pipiens (Linné), Aedes caspius (Pallas), Culiseta longiareolata (Aitken) and Anopheles maculipennis (Meigen). Aqueous extracts of Ricinus communis leaves and Tetraclinis articulata wood showed strong toxic activity against larvae of several mosquitoes. In this study, insecticide effects of these ...

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

    Science.gov (United States)

    Erler, F; Ulug, I; Yalcinkaya, B

    2006-12-01

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

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

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    Michelle L Michalski

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

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

    Science.gov (United States)

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

    2014-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Jennifer E Simpson

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2015-03-01

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

  10. Lectin Activity in Gut Extract of Culex pipiens.

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    Mona Koosha

    2013-06-01

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

  11. Lectin Activity in Gut Extract of Culex pipiens

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2016-01-13

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

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

    Science.gov (United States)

    Savage, Harry M; Kothera, Linda

    2012-12-01

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

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

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    Osta Mike A

    2012-07-01

    Full Text Available Abstract Background Analysis of Culex pipiens mosquitoes collected from a single site in Lebanon in 2005, revealed an alarming frequency of ace-1 alleles conferring resistance to organophosphate insecticides. Following this, in 2006 the majority of municipalities switched to pyrethroids after a long history of organophosphate usage in the country; however, since then no studies have assessed the impact of changing insecticide class on the frequency of resistant ace-1 alleles in C. pipiens. Methods C. pipiens mosquitoes were captured indoors from 25 villages across the country and subjected to established methods for the analysis of gene amplification at the Ester locus and target site mutations in ace-1 gene that confer resistance to organophosphates. Results We conducted the first large-scale screen for resistance to organosphosphates in C. pipiens mosquitoes collected from Lebanon. The frequency of carboxylesterase (Ester and ace-1 alleles conferring resistance to organophosphates were assessed among C. pipiens mosquitoes collected from 25 different villages across the country between December 2008 and December 2009. Established enzymatic assay and PCR-based molecular tests, both diagnostic of the major target site mutations in ace-1 revealed the absence of the F290V mutation among sampled mosquitoes and significant reduction in the frequency of G119S mutation compared to that previously reported for mosquitoes collected from Beirut in 2005. We also identified a new duplicated ace-1 allele, named ace-1D13, exhibiting a resistant phenotype by associating a susceptible and a resistant copy of ace-1 in a mosquito line sampled from Beirut in 2005. Fisher’s exact test on ace-1 frequencies in the new sample sites, showed that some populations exhibited a significant excess of heterozygotes, suggesting that the duplicated allele is still present. Starch gel electrophoresis indicated that resistance at the Ester locus was mainly attributed to the

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

    Science.gov (United States)

    2012-01-01

    Background Analysis of Culex pipiens mosquitoes collected from a single site in Lebanon in 2005, revealed an alarming frequency of ace-1 alleles conferring resistance to organophosphate insecticides. Following this, in 2006 the majority of municipalities switched to pyrethroids after a long history of organophosphate usage in the country; however, since then no studies have assessed the impact of changing insecticide class on the frequency of resistant ace-1 alleles in C. pipiens. Methods C. pipiens mosquitoes were captured indoors from 25 villages across the country and subjected to established methods for the analysis of gene amplification at the Ester locus and target site mutations in ace-1 gene that confer resistance to organophosphates. Results We conducted the first large-scale screen for resistance to organosphosphates in C. pipiens mosquitoes collected from Lebanon. The frequency of carboxylesterase (Ester) and ace-1 alleles conferring resistance to organophosphates were assessed among C. pipiens mosquitoes collected from 25 different villages across the country between December 2008 and December 2009. Established enzymatic assay and PCR-based molecular tests, both diagnostic of the major target site mutations in ace-1 revealed the absence of the F290V mutation among sampled mosquitoes and significant reduction in the frequency of G119S mutation compared to that previously reported for mosquitoes collected from Beirut in 2005. We also identified a new duplicated ace-1 allele, named ace-1D13, exhibiting a resistant phenotype by associating a susceptible and a resistant copy of ace-1 in a mosquito line sampled from Beirut in 2005. Fisher’s exact test on ace-1 frequencies in the new sample sites, showed that some populations exhibited a significant excess of heterozygotes, suggesting that the duplicated allele is still present. Starch gel electrophoresis indicated that resistance at the Ester locus was mainly attributed to the Ester2 allele, which exhibits

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-10-01

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

  17. Dieldrin-resistance in Culex pipiens fatigans in Malaya

    Science.gov (United States)

    Wharton, R. H.

    1958-01-01

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

  18. Lectin Activity in Gut Extract of Culex Pipiens

    Directory of Open Access Journals (Sweden)

    Mona Koosha

    2013-03-01

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

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

    Science.gov (United States)

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

    2014-04-01

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

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

    Science.gov (United States)

    Osório, Hugo Costa; Zé-Zé, Líbia; Alves, Maria João

    2012-05-01

    The host blood-feeding patterns of mosquito vectors affects the likelihood of human exposure to zoonotic pathogens, including West Nile Virus (family Flaviviridae, genus Flavivirus, WNV). In Portugal, data are unavailable regarding the blood-feeding habits of common mosquito species, including Culex pipiens L., considered the primary vector of WNV to humans. The sources of bloodmeals in 203 blood-fed mosquitoes of nine species collected from June 2007 to November 2010 in 34 Portuguese counties were analyzed by sequencing cytochrome-b partial fragments. Cx. pipiens was the most common species collected and successfully analyzed (n = 135/78). In addition, blood-fed females of the following species were analyzed: Ochlerotatus caspius Pallas (n = 20), Culex theileri Theobald (n = 16), Anopheles maculipennis s.l. Meigen (n = 10), Culiseta longiareolata Macquart (n = 7), Aedes aegypti L. (n = 6), Culex perexiguus Theobald (n = 3), Culiseta annulata Schrank (n = 3), and Ochlerotatus detritus Haliday (n = 3). The Cx. pipiens mosquitoes fed predominantly on birds (n = 55/78, 70.5%), with a high diversity of avian species used as hosts, although human blood was identified in 18 specimens (18/78, 23.1%). No significant differences were found between the host-feeding patterns of blood-fed Cx. pipiens collected in residential and nonresidential habitats. The occurrence of human derived blood meals and the presence of a mix avian-human bloodmeal accordingly suggest this species as a potential vector of WNV. Therefore, in Portugal, Cx. pipiens may play a role both in the avian-to-avian enzootic WNV cycle and in the avian-to-mammal transmission. In this context, the identity of Cx. pipiens (considering the forms molestus and pipiens) and the potential consequence on feeding behavior and WNV transmission are discussed.

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

    Science.gov (United States)

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

    2016-12-08

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

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

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

    2011-05-01

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

  3. Asymmetric introgression between sympatric molestus and pipiens forms of Culex pipiens (Diptera: Culicidae in the Comporta region, Portugal

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    Côrte-Real Ana R

    2009-11-01

    Full Text Available Abstract Background Culex pipiens L. is the most widespread mosquito vector in temperate regions. This species consists of two forms, denoted molestus and pipiens, that exhibit important behavioural and physiological differences. The evolutionary relationships and taxonomic status of these forms remain unclear. In northern European latitudes molestus and pipiens populations occupy different habitats (underground vs. aboveground, a separation that most likely promotes genetic isolation between forms. However, the same does not hold in southern Europe where both forms occur aboveground in sympatry. In these southern habitats, the extent of hybridisation and its impact on the extent of genetic divergence between forms under sympatric conditions has not been clarified. For this purpose, we have used phenotypic and genetic data to characterise Cx. pipiens collected aboveground in Portugal. Our aims were to determine levels of genetic differentiation and the degree of hybridisation between forms occurring in sympatry, and to relate these with both evolutionary and epidemiological tenets of this biological group. Results Autogeny and stenogamy was evaluated in the F1 progeny of 145 individual Cx. pipiens females. Bayesian clustering analysis based on the genotypes of 13 microsatellites revealed two distinct genetic clusters that were highly correlated with the alternative traits that define pipiens and molestus. Admixture analysis yielded hybrid rate estimates of 8-10%. Higher proportions of admixture were observed in pipiens individuals suggesting that more molestus genes are being introgressed into the pipiens form than the opposite. Conclusion Both physiological/behavioural and genetic data provide evidence for the sympatric occurrence of molestus and pipiens forms of Cx. pipiens in the study area. In spite of the significant genetic differentiation between forms, hybridisation occurs at considerable levels. The observed pattern of asymmetric

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

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    Linthicum, Kenneth J

    2012-12-01

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

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

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    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

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

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    Fouad El-Akhal

    2015-01-01

    Full Text Available Background. Outbreaks of the West Nile virus infection were reported in Morocco in 1996, 2003, and 2010. Culex pipiens was strongly suspected as the vector responsible for transmission. In the North center of Morocco, this species has developed resistance to synthetic insecticides. There is an urgent need to find alternatives to the insecticides as natural biocides. Objective. In this work, the insecticidal activity of the extract of the local plant Nerium oleander, which has never been tested before in the North center of Morocco, was studied on larval stages 3 and 4 of Culex pipiens. Methods. Biological tests were realized according to a methodology inspired from standard World Health Organization protocol. The mortality values were determined after 24 h of exposure and LC50 and LC90 values were calculated. Results. The extract had toxic effects on the larvae of culicid mosquitoes. The ethanolic extract of Nerium oleander applied against the larvae of Culex pipiens has given the lethal concentrations LC50 and LC90 in the order of 57.57 mg/mL and 166.35 mg/mL, respectively. Conclusion. This investigation indicates that N. oleander could serve as a potential larvicidal, effective natural biocide against mosquito larvae, particularly Culex pipiens.

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

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

    2013-10-01

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

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

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

    2014-02-01

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

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

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    Hossein Dehghan

    2016-01-01

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

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

    Science.gov (United States)

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

    2005-12-01

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

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

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

    2012-12-01

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

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

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

    2005-06-01

    The insecticidal activities of essential oil extracts from leaves, flowers and roots of aromatic plants against fourth-instar larvae of the mosquito Culex pipiens molestus Forskal were determined. Extracts of Foeniculum vulgare Mill were the most toxic, followed by those of Ferula hermonis Boiss, Citrus sinensis Osbeck, Pinus pinea L, Laurus nobilis L and Eucalyptus spp with LC50 values of 24.5, 44.0, 60.0, 75.0, 117.0 and 120.0 mg litre(-1), respectively. Combination tests between the LC50 and the maximum sub-lethal concentration (MSLC) were determined. Over 20 major components were identified in extracts from each plant species tested. Five essential oils and nine pure components were studied for their repellency against mosquito bites. Terpineol and 1,8-cineole were the most effective against Culex pipiens molestus bites offering complete protection for 1.6 and 2 h, respectively.

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

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    H Dehghan

    2010-12-01

    Full Text Available "nAbstract "nBackground: Culex pipiens complex shows variations in morphological and biological characters including differ­ent biological forms and has medical and veterinary importance. Because of having morphological variations, some­times it is not easy to separate this species from Cx. quinquefasciatus and Cx. torrentium. The aim of this study was to  identify the  Culex pipiens complex species in order to use in control programs in the future. "nMethods: This study was carried out in two randomly selected rural villages in Yazd County, eastern Iran using dip­ping technique from April to October 2009. The data were analyzed using SPSS software version 16. "nResults: Average of siphon index in fourth-instrar larvae was 3.86±0.03, the minimum and maximum were calculated 2.43 and 5.14, respectively. Siphon/Saddle index was measured as average, minimum and maximum 3.2±0.2, 2.78, and 4.42 respectively. In our study, only 4 specimens had single seta 1 on segments III and VI (2.5% and the remaining beard double seta (97.5%. The maximum 3-6 branches seta 1a-S and 1b-S (95% were observed on siphon. "nConclusion: More populations of Culex pipiens from different areas of Iran need to be studied to gain complete informa­tion about the taxonomy and ecology of the species in the country. "n  "nKeywords: Culex pipiens complex, larvae, taxonomy, Iran

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

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

    2004-01-01

    The extracts from 7 species of bamboo were tested for larvicidal activity against Culex pipiens pallens. At the tested concentration, the extracts of selected bamboo had different degree of toxic effects on the fourth instar larvae of Culex pipiens pallens. Among them,the extracts of Pleioblastus juxianensis, Brachystachyum albostriatum, Phyllostachys platyglossa and Pleioblastus amarus were found to be effective with LC50values at 24h of 30.65mg/L,53.94mg/L, 41.21 mg/L and 54.49 mg/L respectively, against Culex pipiens pallens larvae. The extract of Pleioblastus juxianensis by Soxhlet method showed stronger activity than the extract obtained by interval-shaking, the LC50 of which were 30.65 mg/L and 48.34 mg/L, respectively.The diethyl ether extract of Pleioblastus juxianensis exhibited better larvicidal activity than the methanol extract and the petroleum ether extract. The results would help to provide the basis for the study of environment acceptable pesticide for mosquito control, and also help to comprehensively utilize the source of bamboo.

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

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

    2011-05-01

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

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

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    Robyn Manley

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

  17. 浙江省淡色库蚊和白纹伊蚊对常用化学杀虫剂的抗性调查%Resistance investigation of Culex pipiens pallens and Aedes albopictus to eight pesticides and resistance control strategy in Zhejiang province

    Institute of Scientific and Technical Information of China (English)

    龚震宇; 侯娟; 任樟尧; 凌锋; 郭颂

    2012-01-01

    目的 了解浙江省淡色库蚊和白纹伊蚊不同地理株对敌敌畏等8种常用杀虫剂的抗性动态,为指导灭蚊工作的深入开展提供科学依据.方法 采用浸渍法,测定4龄期幼虫的半数致死浓度(LC50).结果 金华市淡色库蚊对氯菊酯的抗性处于中抗水平,抗性倍数为11.5倍;绍兴市淡色库蚊对高效氯氰菊酯的抗性处于中抗水平,抗性倍数为11.2倍;各调查点淡色库蚊对其他一些化学杀虫剂均处于低抗水平;金华市白纹伊蚊对敌敌畏已产生高度抗性,抗性倍数为22.8倍,对氯菊酯和胺菊酯的抗性处于中抗水平,抗性倍数分别为13.4和11.4倍;宁波市白纹伊蚊对溴氰菊酯、高效氯氰菊酯的抗性处于中抗水平,抗性倍数分别为17.2和11.8倍;义乌市白纹伊蚊对高效氯氰菊酯已产生高度抗性,抗性倍数为28.8倍,对溴氰菊酯和氯菊酯的抗性处于中抗水平,抗性倍数分别为19.7和18.4倍;各调查点白纹伊蚊对其他一些化学杀虫剂均处于低抗水平.结论 淡色库蚊和白纹伊蚊各地理株对8种常用杀虫剂均产生了不同程度的抗性,以菊酯类最高,应加强对菊酯类杀虫剂的抗性监测及科学合理使用.%Objective To investigate the resistances of Culex pipiens pallens and Aedes albopictus to eight insecticides for making the dynamic mosquitoe control strategy in Zhejiang. Methods Immersion method of pesticide was used to assay the medium lethal concentration (LC50) for the fourth instar larvae of mosquitoes. Results The resistances of Cx. pipiens pallens in Jinhua city to permethrin was at medium level, the RR 11.5. The resistances of Cx. pipiens pallens in Shaoxing city to beta-cypermethrin was at medium level, the RR 11.2. The Cx. pipiens pallens showed low resistance to other types of insecticides in all cities. In Jinhua city, the resistances of Ae. albopictus to dichlorvos was at high level, the RR 22.8. The resistances of Ae. albopictus to

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

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    Badawy MEI

    2016-09-01

    Full Text Available Mohamed EI Badawy,1 Nehad EM Taktak,2 Osama M Awad,2 Souraya A Elfiki,2 Nadia E Abou El-Ela2 1Department of Pesticide Chemistry and Technology, Faculty of Agriculture, 2Department of Tropical Health, High Institute of Public Health, Alexandria University, Alexandria, Egypt Abstract: Efficacy of spinosad and malathion loaded in eco-friendly biodegradable formulations was evaluated for controlling Culex pipiens larvae. Malathion (organophosphorus larvicide and spinosad (naturally derived insecticide were loaded on chitosan/alginate/gelatin capsules. Capsules were characterized by size measurement, scanning electron microscopy, Fourier transform infrared spectroscopy, and water uptake. In vitro release kinetics of the larvicides was studied in the running and stagnant water. Biochemical studies on the larvae treated with technical and formulated insecticides were also demonstrated. The results indicated that the released spinosad was active for a long time up to 48 and 211 days in the running and stagnant water, respectively. However, the capsules loaded with malathion showed larvicidal activity for 20 and 27 days in the running and stagnant water, respectively. Technical and formulated malathion and spinosad had an inhibition effect on acetylcholinesterase, carboxylesterase, and glutathione S-transferase. The results proved that the prepared capsules consisting of biodegradable polymers containing larvicides could be effective as controlled-release formulation against C. pipiens larvae for a long period. Keywords: chitosan capsules, larvicide, controlled-release formulation, swelling, mosquitocidal activity, Culex pipiens, biochemical study

  19. Plasmodium relictum (lineages pSGS1 and pGRW11): complete synchronous sporogony in mosquitoes Culex pipiens pipiens.

    Science.gov (United States)

    Kazlauskienė, Rita; Bernotienė, Rasa; Palinauskas, Vaidas; Iezhova, Tatjana A; Valkiūnas, Gediminas

    2013-04-01

    Plasmodium relictum is a widespread invasive agent of avian malaria, responsible for acute, chronic and debilitating diseases in many species of birds. Recent PCR-based studies revealed astonishing genetic diversity of avian malaria parasites (genus Plasmodium), with numerous genetic lineages deposited in GenBank. Many studies addressed distribution and evolutionary relationships of avian Plasmodium lineages, but information about patterns of development of different lineages in mosquito vectors remains insufficient. Here we present data on sporogonic development of 2 widespread mitochondrial cytochrome b lineages (cyt b) of P. relictum (pSGS1 and pGRW11) in mosquito Culex pipiens pipiens. Genetic distance between these lineages is 0.2%; they fall in a well-supported clade in the phylogenetic tree. Three P. relictum strains were isolated from common crossbill (Loxia curvirostra, lineage pSGS1), domestic canary (Serinus canaria domestica, pSGS1) and house sparrow (Passer domesticus, pGRW11). These strains were multiplied in domestic canaries and used as donors of malarial gametocytes to infect C. p. pipiens. Mosquitoes were allowed to take blood meal on infected canaries and then dissected on intervals to study development of sporogonic stages. All 3 strains developed synchronously and completed sporogony in this vector, with infective sporozoites reported in the salivary glands on the day 14 after infection. Ookinetes, oocysts and sporozoites of all strains were indistinguishable morphologically. This study shows that patterns of sporogonic development of the closely related lineages pSGS1 and pGRW11 and different strains of the lineage pSGS1 of P. relictum are similar indicating that phylogenetic trees based on the cyt b gene likely can be used for predicting sporogonic development of genetically similar avian malaria lineages in mosquito vectors. Copyright © 2013 Elsevier Inc. All rights reserved.

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

    Institute of Scientific and Technical Information of China (English)

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

    2013-01-01

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

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

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    Yaser Salim-Abadi

    2016-10-01

    Full Text Available Background: During recent years transmission of Dirofilaria immitis (dog heart worm by Culex pipiens and West Nile virus have been reported from Iran. The present study was preformed for evaluating the susceptibility status of Cx. pipiens collected from capital city of Tehran, Iran.Methods: Four Insecticides including: DDT 4%, Lambdacyhalothrin 0.05%, Deltamethrin 0.05% and Cyfluthrin 0.15 % according to WHO standard  methods were used for evaluating the susceptibility status of Cx. pipiens from Tehran moreover  For comparison susceptibility status a Laboratory strain also was used.  Bioassay data were ana­lyzed using Probit program. The lethal time for 50% and 90% mortality (LT50 and LT90 values were calculated from regression line.Results: The susceptibility status of lab strain of Cx. pipiens revealed that it is susceptible to Lambdacyhalothrin, Deltamethrin, Cyfluthrin and resistant to DDT. Moreover cyfluthrin with LT50=36 seconds and DDT with LT50=3005 seconds had the least and most LT50s. Field population was resistance to all tested insecticides and DDT yielded no mortality.Conclusion: Highly resistance level against all WHO recommended imagicides were detected in field populations. We suggest more biochemical and molecular investigations to detect resistance mechanisms in the field population for further decision of vector control.

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

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    Jazem Abdullah Mahyoub

    2016-05-01

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

  3. LINKAGE OF KNOCKDOWN RESISTANCE AND THE SODIUM CHANNEL GENE MUTATION IN CULEX PIPIENS PALLENS *%淡色库蚊(Culex pipiens Pallens)与击倒抗性(kdr)相关的钠通道基因突变

    Institute of Scientific and Technical Information of China (English)

    宋锋林; 赵彤言; 董言德; 曹晓梅; 张晓龙

    2005-01-01

    本研究采用RT-PCR技术,使用简并引物分别从淡色库蚊(Culex pipiens pallens)敏感品系和抗溴氰菊酯品系中扩增出钠通道ⅡS4~ⅡS6区域的基因片段,长度为359bp.该基因片段所编码的氨基酸与黑尾果蝇(Drosophila melanogaster)、家蝇(Musca domestica)、埃及伊蚊(Aedes aegypti)、冈比亚按蚊(Anopheles gambiae)及德国小蠊(Blattella germanica)等昆虫相应区域的氨基酸序列具有较高的同源性,其同源性分别为95.8%,95.0%,100.0%,98.3%和95.0%.经序列比对,确认抗溴氰菊酯品系淡色库蚊钠通道基因在1014位点发生了突变:该位点的碱基"A"突变为"T",其对应氨基酸由亮氨酸(L)变为苯丙氨酸(F),该突变(L1014F型)在多种昆虫中较为常见.

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

    Science.gov (United States)

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

    2014-09-01

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

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

    OpenAIRE

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

    2010-01-01

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

  6. The Effect of West Nile Virus Infection on the Midgut Gene Expression of Culex pipiens quinquefasciatus Say (Diptera: Culicidae

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    Chelsea T. Smartt

    2016-12-01

    Full Text Available The interaction of the mosquito and the invading virus is complex and can result in physiological and gene expression alterations in the insect. The association of West Nile virus (WNV and Culex pipiens quinquefasciatus mosquitoes results in measurable changes in gene expression; 22 gene products were shown previously to have altered expression. Sequence analysis of one product, CQ G1A1, revealed 100% amino acid identity to gram negative bacteria binding proteins (CPQGBP in Cx. p. quinquefasciatus, Aedes aegypti (70% and Anopheles gambiae (63% that function in pathogen recognition. CQ G1A1 also was differentially expressed following WNV infection in two populations of Cx. p. quinquefasciatus colonized from Florida with known differences in vector competence for WNV and showed spatial and temporal gene expression differences in midgut, thorax, and carcass tissues. These data suggest gene expression of CQ G1A1 is influenced by WNV infection and the WNV infection-controlled expression differs between populations and tissues.

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

    Institute of Scientific and Technical Information of China (English)

    Hossein Dehghan; Javid Sadraei; Seyed Hassan Moosa-Kazemi

    2011-01-01

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

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

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    Jason L Rasgon

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

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2011-03-01

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

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

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    Mohsen Karami

    2016-01-01

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

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

    Science.gov (United States)

    Farajollahi, Ary; Fonseca, Dina M.; Kramer, Laura D.; Kilpatrick, A. Marm

    2011-01-01

    The transmission of vector-borne pathogens is greatly influenced by the ecology of their vector, which is in turn shaped by genetic ancestry, the environment, and the hosts it feeds on. One group of vectors, the mosquitoes in the Culex pipiens complex, play key roles in the transmission of a range of pathogens including several viruses such as West Nile and St. Louis encephalitis viruses, avian malaria (Plasmodium spp.), and filarial worms. The Cx. pipiens complex includes Cx. pipiens pipiens with two forms, pipiens and molestus, Cx. pipiens pallens, Cx. quinquefasciatus, Cx. australicus, and Cx. globocoxitus. While several members of the complex have limited geographic distributions, Cx. pipiens pipiens and Cx. quinquefasciatus are found in all known urban and sub-urban temperate and tropical regions, respectively, across the world, where they are often principal disease vectors. In addition, hybrids are common in areas of overlap. Although gaps in our knowledge still remain, the advent of genetic tools has greatly enhanced our understanding of the history of speciation, domestication, dispersal, and hybridization. We review the taxonomy, genetics, evolution, behavior, and ecology, of members of the Cx. pipiens complex and their role in the transmission of medically important pathogens. The adaptation of Cx. pipiens complex mosquitoes to human-altered environments led to their global distribution through dispersal via humans and, combined with their mixed feeding patterns on birds and mammals (including humans), increased the transmission of several avian pathogens to humans. We highlight several unanswered questions that will increase our ability to control diseases transmitted by these mosquitoes. PMID:21875691

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

    Science.gov (United States)

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

    2015-01-01

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

  14. Behavioural response of female Culex pipiens pallens to common host plant volatiles and synthetic blends.

    Science.gov (United States)

    Yu, Bao-Ting; Ding, Yan-Mei; Mo, Jian-Chu

    2015-11-17

    Most mosquito species need to obtain sugar from host plants. Little is known about the chemical cues that Culex pipiens pallens use during their orientation to nectar host plants. In this study, we investigated the behavioural responses of female Cx. pipiens pallens to common floral scent compounds and their blends. Behavioural responses of female Cx. pipiens pallens to 18 individual compounds at different concentrations were determined in the olfactometer bioassays. A synthetic blend composed of behaviourally active compounds was formulated, and its attractiveness to mosquitoes was tested. Several most attractive compounds constituted a reduced blend, and its attractiveness was tested against the solvent and the full blend, respectively. Mosquito response in the olfactometer was analyzed by comparing the percentages of mosquitoes caught in the two arms by χ(2) test (observed versus expected). Fifteen of the 18 compounds were attractive to female Cx. pipiens pallens in the dose-dependent bioassays, with the exception of β-pinene, acetophenone and nonanal. (68.00 ± 2.49) % mosquitoes responded to the full blend composed of these 15 compounds on their optimal doses when tested against the solvent, with the preference index at 46.11 ± 3.57. Six individual compounds whose preference indices were over 40 constituted the reduced blend, and it attracted (68.00 ± 1.33) % mosquitoes when tested against the solvent while its preference index was 42.00 ± 3.54. When tested against the full blend simultaneously in the olfactometer, the reduced blend could attract (45.00 ± 2.69) % of released mosquitoes, which was as attractive as the full blend. Our results demonstrate that female Cx. pipiens pallens is differentially attracted by a variety of compounds at different concentrations. Alteration of the concentration strongly affects the attractiveness of the synthetic blend. Several floral scent volatiles might be the universal olfactory cues for various

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

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    Liu Yangyang

    2011-12-01

    Full Text Available Abstract Background In China, large amounts of chemical insecticides are applied in fields or indoors every year, directly or indirectly bringing selection pressure on vector mosquitoes. Culex pipiens complex has evolved to be resistant to all types of chemical insecticides, especially organophosphates, through carboxylesterases. Six resistant carboxylesterase alleles (Ester were recorded previously and sometimes co-existed in one field population, representing a complex situation for the evolution of Ester genes. Results In order to explore the evolutionary scenario, we analyzed the data from an historical record in 2003 and a recent investigation on five Culex pipiens pallens populations sampled from north China in 2010. Insecticide bioassays showed that these five populations had high resistance to pyrethroids, medium resistance to organophosphates, and low resistance to carbamates. Six types of Ester alleles, EsterB1, Ester2, Ester8, Ester9, EsterB10, and Ester11 were identified, and the overall pattern of their frequencies in geographic distribution was consistent with the report seven years prior to this study. Statistical correlation analysis indicated that Ester8 and Ester9 positively correlated with resistance to four insecticides, and EsterB10 to one insecticide. The occurrences of these three alleles were positively correlated, while the occurrence of EsterB1 was negatively correlated with Ester8, indicating an allelic competition. Conclusion Our analysis suggests that one insecticide can select multiple Ester alleles and one Ester allele can work on multiple insecticides. The evolutionary scenario of carboxylesterases under insecticide selection is possibly "one to many".

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

    Science.gov (United States)

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

    2014-05-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

    El-Monairy, Olfat M

    2015-04-01

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

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

    Directory of Open Access Journals (Sweden)

    Linna Shi

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

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

    Science.gov (United States)

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

    2016-11-01

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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2016-05-01

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

  3. Molecular cloning and preliminary function study of iron responsive element binding protein 1 gene from cypermethrin-resistant Culex pipiens pallens

    Directory of Open Access Journals (Sweden)

    Tan Wenbin

    2011-11-01

    Full Text Available Abstract 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.

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

    OpenAIRE

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

  6. Insecticide susceptibility in larval populations of the West Nile vector Culex pipiens L.(Diptera: Culicidae) in Saudi Arabia

    Institute of Scientific and Technical Information of China (English)

    Al Thabiani Aziz; Jazem Abdullah Mahyoub; Hasibur Rehman; Shalini Saggu; Kadarkarai Murugan; Chellasamy Panneerselvam; Majed Salum S.Alrefaei; Marcello Nicoletti; Hui Wei; Angelo Canale; Giovanni Benelli

    2016-01-01

    Objective: To investigate the susceptibility to some conventional and non-conventional insecticides in laboratory and field larval populations of the West Nile vector Culex pipiens L.(Cx. pipiens), the dominant species in Jeddah Province, Saudi Arabia.Methods: The tested conventional insecticides were Actikil and Pesgard, while the nonconventional ones were Bacilod, Dudim and Baycidal. Probit analysis and photomicroscopical observations were carried out to shed light on acute toxicity in laboratory and field Cx. pipiens strains.Results: Cx. pipiens were more susceptible to Pesgard(LC50: 0.045 and 0.032 mg/L)than Actikil(0.052 and 0.038 mg/L) and Bacilod(0.129 and 0.104 mg/L), for the field and laboratory strains, respectively. Results showed that treatments with the chitin synthesis inhibitor Dudim and Baycidal evoked morphological effects similar to those induced by other insect growth regulators. According to IC50 values obtained(concentration which to inhibit the emergence of 50% of mosquito adults), the compound Dudim(0.000 3 and 0.000 1 mg/L) was more effective against Cx. pipiens L. mosquitoes than Baycidal(0.000 4 and 0.000 3 mg/L) for both the field and laboratory strains, respectively.Conclusions: Our results provide baseline data to enhance control programs and orient public health decisions on the selection of pesticides against mosquito vectors in Saudi Arabia.

  7. Insecticide susceptibility in larval populations of the West Nile vector Culex pipiens L. (Diptera:Culicidae) in Saudi Arabia

    Institute of Scientific and Technical Information of China (English)

    Al Thabiani Aziz; Angelo Canale; Giovanni Benelli; Jazem Abdullah Mahyoub; Hasibur Rehman; Shalini Saggu; Kadarkarai Murugan; Chellasamy Panneerselvam; Majed Salum S Alrefaei; Marcello Nicoletti; Hui Wei

    2016-01-01

    Objective: To investigate the susceptibility to some conventional and non-conventional insecticides in laboratory and field larval populations of the West Nile vector Culex pipiens L. (Cx. pipiens), the dominant species in Jeddah Province, Saudi Arabia. Methods: The tested conventional insecticides were Actikil and Pesgard, while the non-conventional ones were Bacilod, Dudim and Baycidal. Probit analysis and photo-microscopical observations were carried out to shed light on acute toxicity in laboratory and field Cx. pipiens strains. Results: Cx. pipiens were more susceptible to Pesgard (LC50: 0.045 and 0.032 mg/L) than Actikil (0.052 and 0.038 mg/L) and Bacilod (0.129 and 0.104 mg/L), for the field and laboratory strains, respectively. Results showed that treatments with the chitin syn-thesis inhibitor Dudim and Baycidal evoked morphological effects similar to those induced by other insect growth regulators. According to IC50 values obtained (concen-tration which to inhibit the emergence of 50%of mosquito adults), the compound Dudim (0.000 3 and 0.000 1 mg/L) was more effective against Cx. pipiens L. mosquitoes than Baycidal (0.000 4 and 0.000 3 mg/L) for both the field and laboratory strains, respectively. Conclusions: Our results provide baseline data to enhance control programs and orient public health decisions on the selection of pesticides against mosquito vectors in Saudi Arabia.

  8. Seasonal dynamics of insecticide resistance, multiple resistance, and morphometric variation in field populations of Culex pipiens.

    Science.gov (United States)

    Taskin, Belgin Gocmen; Dogaroglu, Taylan; Kilic, Sercan; Dogac, Ersin; Taskin, Vatan

    2016-05-01

    Resistance to insecticides that impairs nervous transmission has been widely investigated in mosquito populations as insecticides are crucial to effective insect control. The development of insecticide resistance is also of special interest to evolutionary biologists since it represents the opportunity to observe the genetic consequences of a well-characterized alteration in the environment. Although the frequencies of resistance alleles in Culex pipiens populations against different groups of insecticides have been reported, no detailed information is available on the relative change in these allele frequencies over time. In this study, we collected mosquitoes of the Cx. pipiens complex from six locations in three seasons in the Aegean region of Turkey and examined the i) seasonal variations in resistance to four different chemical classes of insecticides, ii) seasonal fluctuations in frequencies of resistance-associated target-site mutations of the three genes (ace-1, kdr, and Rdl), and iii) potential seasonal variations in wing morphometric characters that may be modified in resistant mosquitoes. Our bioassay results indicated the presence of different levels of resistance to all tested insecticides for all three seasons in all locations. The results of the PCR-based molecular analysis revealed low frequencies of mutations in ace-1 and Rdl that are associated with resistance to malathion, bendiocarb, and dieldrin and no obvious seasonal changes. In contrast, we detected high frequencies and striking seasonal changes for two kdr mutations associated with resistance to DDT and pyrethroids. In addition, the evaluation of the field populations from all seasons in terms of the combinations of polymorphisms at four resistance-associated mutations did not reveal the presence of insects that are resistant to all pesticides. Results from the morphological analysis displayed a similar pattern for both wings and did not show a clear separation among the samples from the

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

    Science.gov (United States)

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

    2016-11-01

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

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

    Directory of Open Access Journals (Sweden)

    Doug E Brackney

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

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

    Science.gov (United States)

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

    2015-03-01

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

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

    Science.gov (United States)

    Sim, Cheolho; Denlinger, David L

    2008-05-06

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

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

    Science.gov (United States)

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

    2015-09-01

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

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

    Directory of Open Access Journals (Sweden)

    H Dehghan

    2010-12-01

    Methods: This study was carried out in two randomly selected rural villages in Yazd County, eastern Iran using dip­ping technique from April to October 2009. The data were analyzed using SPSS software version 16. Results: Average of siphon index in fourth-instrar larvae was 3.86±0.03, the minimum and maximum were calculated 2.43 and 5.14, respectively. Siphon/Saddle index was measured as average, minimum and maximum 3.2±0.2, 2.78, and 4.42 respectively. In our study, only 4 specimens had single seta 1 on segments III and VI (2.5% and the remaining beard double seta (97.5%. The maximum 3-6 branches seta 1a-S and 1b-S (95% were observed on siphon. Conclusion: More populations of Culex pipiens from different areas of Iran need to be studied to gain complete informa­tion about the taxonomy and ecology of the species in the country.

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

    Science.gov (United States)

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

    2006-03-01

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

  16. Evolutionary genomics of Culex pipiens: global and local adaptations associated with climate, life-history traits and anthropogenic factors.

    Science.gov (United States)

    Asgharian, Hosseinali; Chang, Peter L; Lysenkov, Sergey; Scobeyeva, Victoria A; Reisen, William K; Nuzhdin, Sergey V

    2015-07-07

    We present the first genome-wide study of recent evolution in Culex pipiens species complex focusing on the genomic extent, functional targets and likely causes of global and local adaptations. We resequenced pooled samples of six populations of C. pipiens and two populations of the outgroup Culex torrentium. We used principal component analysis to systematically study differential natural selection across populations and developed a phylogenetic scanning method to analyse admixture without haplotype data. We found evidence for the prominent role of geographical distribution in shaping population structure and specifying patterns of genomic selection. Multiple adaptive events, involving genes implicated with autogeny, diapause and insecticide resistance were limited to specific populations. We estimate that about 5-20% of the genes (including several histone genes) and almost half of the annotated pathways were undergoing selective sweeps in each population. The high occurrence of sweeps in non-genic regions and in chromatin remodelling genes indicated the adaptive importance of gene expression changes. We hypothesize that global adaptive processes in the C. pipiens complex are potentially associated with South to North range expansion, requiring adjustments in chromatin conformation. Strong local signature of adaptation and emergence of hybrid bridge vectors necessitate genomic assessment of populations before specifying control agents.

  17. Effects of microcosm scaling and food resources on growth and survival of larval Culex pipiens

    Directory of Open Access Journals (Sweden)

    Paradise Christopher J

    2001-08-01

    Full Text Available Abstract Background We used a simple experimental design to test for the effects of microcosm scaling on the growth and survival of the mosquito, Culex pipiens. Microcosm and mesocosm studies are commonly used in ecology, and there is often an assumption that scaling doesn't affect experimental outcomes. The assumption is implicit in the design; choice of mesocosms may be arbitrary or based on convenience or cost. We tested the hypothesis that scale would influence larvae due to depth and surface area effects. Larvae were predicted to perform poorly in microcosms that were both deep and had small openings, due to buildup of waste products, less exchange with the environment, and increased competition. To determine if the choice of scale affected responses to other factors, we independently varied leaf litter quantity, whose effects on mosquitoes are well known. Results We found adverse effects of both a lower wall surface area and lower horizontal surface area, but microcosm scale interacted with resources such that C. pipiens is affected by habitat size only when food resources are scarce. At low resource levels mosquitoes were fewer, but larger, in microcosms with smaller horizontal surface area and greater depth than in microcosms with greater horizontal surface area and shallower depth. Microcosms with more vertical surface area/volume often produced larger mosquitoes; more food may have been available since mosquitoes browse on walls and other substrates for food. Conclusions The interaction between habitat size and food abundance is consequential to aquatic animals, and choice of scale in experiments may affect results. Varying surface area and depth causes the scale effect, with small horizontal surface area and large depth decreasing matter exchange with the surrounding environment. In addition, fewer resources leads to less leaf surface area, and the effects of varying surface area will be greater under conditions of limiting resources

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

    Directory of Open Access Journals (Sweden)

    Ji-Wen Zhang

    2013-12-01

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

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

    Science.gov (United States)

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

    2014-02-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2010-02-01

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

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

    Science.gov (United States)

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

    2009-12-01

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

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

    National Research Council Canada - National Science Library

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

    2014-01-01

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

  4. Evaluation of Some Plant Fruit Extracts for the Control of West Nile Virus Vector Culex pipiens (Diptera: Culicidae)

    Science.gov (United States)

    Koc, Samed; Evren, Ozay Hasan; Cetin, Huseyin

    2016-01-01

    Background: The extracts of different parts of plants were found very effective against various pests. The aim of this research was to determine the insecticidal activity of fruit methanol extracts obtained from Melia azedarach (Meliaceae), Phoenix theophrasti (Arecaceae), Styphnolobium japonicum (Fabaceae) and Pyracantha coccinea (Rosaceae) against the larvae of Culex pipiens (Diptera: Culicidae). Methods: The fruits of test plants were collected from the Campus of Akdeniz University, Antalya, Turkey in 2013. A series of concentrations of the extracts ranging from 62.5–1000 ppm were tested against second instar larvae. Results: Only the extracts of Me. azedarach and Ph. theoprasti showed significant larvicidal activity against Cx. pipiens and the LC50 values of these extracts were found to be 169.48 and 220.60 ppm, respectively. This is the first research investigating the insecticidal or larvicidal activity of Ph. theophrasti, St. japonicum and Py. coccinea extracts on mosquitoes. Conclusion: The methanol extract of fruits of Me. azedarach and Ph. theophrasti showed significantly higher larvicidal activity against Cx. pipiens. PMID:28032112

  5. Potential of biologically active plant oils to control mosquito larvae (Culex pipiens, Diptera: Culicidae) from an Egyptian locality.

    Science.gov (United States)

    Khater, Hanem Fathy; Shalaby, Afaf Abdel-Salam

    2008-01-01

    The insecticidal effect of six commercially available plant oils was tested against 4th larval instars of Culex pipiens. Larvae were originally collected from Meit El-Attar, Qalyubia Governorate, Egypt, and then reared in the laboratory until F1 generation. The LC50 values were 32.42, 47.17, 71.37, 83.36, 86.06, and 152.94 ppm for fenugreek (Trigonella foenum-grecum), earth almond (Cyperus esculentus), mustard (Brassica compestris), olibanum (Boswellia serrata), rocket (Eruca sativa), and parsley (Carum ptroselinum), respectively. The tested oils altered some biological aspects of C. pipiens, for instance, developmental periods, pupation rates, and adult emergences. The lowest concentrations of olibanum and fenugreek oils caused remarkable prolongation of larval and pupal durations. Data also showed that the increase of concentrations was directly proportional to reduction in pupation rates and adult emergences. Remarkable decrease in pupation rate was achieved by mustard oil at 1000 ppm. Adult emergence was suppressed by earth almond and fenugreek oils at 25 ppm. In addition, the tested plant oils exhibited various morphological abnormalities on larvae, pupae, and adult stages. Consequently, fenugreek was the most potent oil and the major cause of malformation of both larval and pupal stages. Potency of the applied plant oils provided an excellent potential for controlling C. pipiens.

  6. Identification of Culex pipiens complex mosquitoes in a hybrid zone of West Nile virus transmission in Fresno County, California.

    Science.gov (United States)

    McAbee, Rory D; Green, Emily N; Holeman, Jodie; Christiansen, Julie; Frye, Niki; Dealey, Katherine; Mulligan, F Steve; Brault, Aaron C; Cornel, Anthony J

    2008-02-01

    Culex pipiens sensu lato mosquitoes were collected from 24 gravid traps (mid-June to mid-October, 2005) in Fresno County, CA. Captured gravid females were allowed to oviposit before sibling species identification by Ace.2 PCR and detection of West Nile virus (WNV) RNA by RT-PCR were performed on the mother and her offspring. Of the 442 Cx. pipiens s.l. female mosquitoes collected, 88 were positive for WNV viral RNA (peaked in August) with no significant differences among complex members or habitat. Vertical transmission was detected in 4 out of 20 families originating from WNV-positive mothers, however, in only a small number of offspring from each family. Out of 101 families that had PCR-based maternal and offspring identifications, the offspring from 15 families produced inexplicable amplicon patterns, suggesting ambiguities in the PCR assay identifications. Male genitalia (DV/D ratio) and Ace.2 PCR identifications revealed numerous discrepancies in our ability to accurately determine the identity of Cx. pipiens complex members in the hybrid zone of Fresno County.

  7. Ankyrin repeat domain-encoding genes in the wPip strain of Wolbachia from the Culex pipiens group

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    Parkhill Julian

    2007-09-01

    Full Text Available Abstract Background Wolbachia are obligate endosymbiotic bacteria maternally transmitted through the egg cytoplasm that are responsible for several reproductive disorders in their insect hosts, such as cytoplasmic incompatibility (CI in infected mosquitoes. Species in the Culex pipiens complex display an unusually high number of Wolbachia-induced crossing types, and based on present data, only the wPip strain is present. Results The sequencing of the wPip strain of Wolbachia revealed the presence of 60 ankyrin repeat domain (ANK encoding genes and expression studies of these genes were carried out in adult mosquitoes. One of these ANK genes, pk2, is shown to be part of an operon of three prophage-associated genes with sex-specific expression, and is present in two identical copies in the genome. Another homolog of pk2 is also present that is differentially expressed in different Cx. pipiens group strains. A further two ANK genes showed sex-specific regulation in wPip-infected Cx. pipiens group adults. Conclusion The high number, variability and differential expression of ANK genes in wPip suggest an important role in Wolbachia biology, and the gene family provides both markers and promising candidates for the study of reproductive manipulation.

  8. Effects of a Red Marker Dye on Aedes and Culex Larvae: Are There Implications for Operational Mosquito Control?

    Science.gov (United States)

    Unlu, Isik; Leisnham, Paul T; Williams, Gregory M; Klingler, Kim; Dow, Garrett W; Kirchoff, Nicole; Jin, Sophie; Delisi, Nicholas; Montenegro, Katherine; Faraji, Ary

    2015-12-01

    Marker dyes are often mixed with liquid insecticide formulations prior to field applications to accurately determine the characteristics and penetration of droplets into targeted habitats. We have been using FD&C Red 40 Granular DM food dye at the rate of 20 g/liter in liquid solutions of Bacillus thuringiensis israelensis (Bti) for area-wide larvicide applications against the Asian tiger mosquito, Aedes albopictus. The Bti and dye mix ratio has been recommended by pesticide manufacturers for testing under operational conditions, but no data exist on the effects of the dye itself on mosquito larvae. We tested the effects of the FD&C Red 40 food dye in laboratory bioassays against different strains of Ae. albopictus (New Jersey and Maryland) and Culex pipiens pipiens (Utah) at rates of 0.039 to 80.0 g/liter. We also conducted field application trials to measure dye concentrations up to 100 m downwind when mixed and applied according to manufacturer instructions. In laboratory bioassays, we found that mean survival in cups with dye were significantly different from the controls beginning at 10.0 g/liter for New Jersey Ae. albopictus and at 20.0 g/liter for Maryland Ae. albopictus and Utah Cx. p. pipiens. In field application trials, we recorded a maximum volume density of 1,152.8 nl/cm(2) and calculated the maximum concentration of dye at 9.09 × 10(-3) g/liter. Our results showed that although we detected greater effects of dye on Ae. albopictus in New Jersey experiments than Ae. albopictus in Maryland and Cx. p. pipiens from Utah, concentrations of the dye during operational applications were at least 1,100 times below concentrations that exhibited toxic effects for either species in the laboratory, suggesting that the dye will not interfere with accuracy of field bioassays. Our results conclusively demonstrate that the addition of the FD&C Red 40 marker dye does not alter the efficacy of the pesticide formulation by skewing results, but rather provides a valuable

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

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    Gul Zamin Khan

    2016-06-01

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

  10. 浦东国际机场致倦库蚊和淡色库蚊的调查研究%An investigation of Culex pipiens quinquefasciatus and Culex pipiens pallens in Pudong International Airport

    Institute of Scientific and Technical Information of China (English)

    曹敏; 何宇平; 李平; 田桢干

    2011-01-01

    Objective To investigate the distribution, seasonal prevalence, diurnal rhythm, bitting and breeding ot Culex pipiens quinquefasciatus and Cx. pipiens pallens in Pudong International Airport. Methods Sample collection was done by means of bednet trap, lamp baited trap, human baited trap, larvae dipping and labor hour method. Results It was found that Cx. pipiens quinquefasciatus and Cx. pipiens pallens were the dominant species of mosquitoes in Pudong International Airport, which were harmful to human health from April to November. The findings from the lamp baited trap showed a slope-shaped curve for the seasonal fluctuation of the insects, beginning in April, peaking from May to June and declining gradually from October and disappearing at the end of November. The bednet trap revealed that the insects were active predominantly in the evening and at night, with peak activity seen 1-4 h after the sunset and little movement during the day. The human baited trap indicated that the peak time of bitting was at 21:00 o'clock, with a maximum frequency of 42 times/15 min). The number of mosquitos that entered each room was highest from 19:00 to 21:00 with the highest burglary rate being 9 mosquitos per 15 min. The larvae were mainly breeding in still sewage or clean water in ponds, pools, bottomlands, ditches and containers, etc. Conclusion Cx. pipiens quinquefasciatus and Cx. pipiens pallens are common human-biting species in Pudong International Airport. The data on the seasonal prevalence, diurnal rhythm, bitting and breeding of Cx. pipiens quinquefasciatus and Cx. pipiens pallens contribute to the prevention and control of the insects and related vector-borne diseases.%目的 了解致倦库蚊和淡色库蚊在浦东机场的分布与活动规律.方法 帐诱法、灯诱法、人诱法、捞勺法和人工小时法.结果 致倦库蚊和淡色库蚊是浦东国际机场的优势蚊种,4-11月均有危害;灯诱法调查,季节消长呈坡型,蚊虫于4月出现,5-6

  11. 竹提取物对淡色库蚊Culex pipiens pallens幼虫的活性评价%EVALUATION OF EXTRACTS FROM BAMBOO FOR BIOLOGICAL ACTIVITY AGAINST CULEX PIPIENS PALLENS

    Institute of Scientific and Technical Information of China (English)

    操海群; 岳永德; 彭镇华; 花日茂; 汤锋

    2004-01-01

    报道了竹提取物对淡色库蚊Culex pipiens pallens幼虫的毒杀作用.研究结果表明,巨县苦竹(Pleioblastusjuxianensis)、白纹短穗竹(Brachystachyum albostriatum)、灰水竹(Phyllostachysplatyglossa)和苦竹(Pleioblastus amarus)提取物对淡色库蚊幼虫的24h致死中浓度(LC50)分别为30.65 mg/L、53.94 mg/L、41.21 mg/L、54.49 mg/L.巨县苦竹索氏抽提物对淡色库蚊幼虫的毒杀作用明显强于间歇振荡提取物,前者对淡色库蚊幼虫的LC50为30.65 mg/L,95%置信限27.12~34.63 mg/L;后者的LC50为48.34 mg/L,95%置信限为40.37~59.62 mg/L.巨县苦竹乙醚浸提物对淡色库蚊幼虫的毒杀作用效果显著,125mg/L浓度时12h校正死亡率为56.67%,24h后达92.90%;石油醚浸提物及甲醇浸提物对淡色库蚊幼虫的毒杀作用则不明显,24h校正死亡率均不超过40%.研究结果将有助于综合利用竹类资源,开发新型环境友好农药.%The extracts from 7 species of bamboo were tested for larvicidal activity against Culex pipiens pallens. At the tested concentration, the extracts of selected bamboo had different degree of toxic effects on the fourth instar larvae of Culex pipiens pallens. Among them,the extracts of Pleioblastus juxianensis, Brachystachyum albostriatum, Phyllostachys platyglossa and Pleioblastus amarus were found to be effective with LC50values at 24h of 30.65 mg/L,53.94 mg/L, 41.21 mg/L and 54.49 mg/L respectively, against Culex pipiens pallens larvae. The extract of Pleioblastus juxianensis by Soxhlet method showed stronger activity than the extract obtained by interval-shaking, the LC50 of which were 30.65 mg/L and 48.34 mg/L, respectively.The diethyl ether extract of Pleioblastus juxianensis exhibited better larvicidal activity than the methanol extract and the petroleum ether extract. The results would help to provide the basis for the study of environment acceptable pesticide for mosquito control, and also help to comprehensively utilize the source of

  12. Efficacy of fipronil combined with permethrin commercial spot on (Effitix) preventing Culex pipiens from feeding on dogs.

    Science.gov (United States)

    Franc, Michel; Lienard, Emmanuel; Jacquiet, Philippe; Bonneau, Stephane; Bouhsira, Emilie

    2015-06-01

    A controlled clinical trial was carried out to assess the adulticidal and anti-feeding effectiveness of a spot-on combining fipronil and permethrin (Effitix, Virbac, Carros, France) in preventing Culex pipiens from feeding on dogs. Twelve dogs with equal sensitivity to mosquitoes were included in the study and divided into two groups of six dogs: an untreated control group and a group treated with Effitix. All dogs were challenged with 80 females C. pipiens for 90 ± 5 min on days -7, 1, 7, 14, 21, and 28 (day 0 being treatment day). The number of engorged, dead, and live mosquitoes was determined after each exposure to treated and untreated dogs. Dead mosquitoes were also counted 24 h after exposure. The anti-feeding effect of the spot-on formulation was 100, 99.5, 97.7, 98.3, and 96.7% on days 1, 7, 14, 21, and 28, respectively. The mortality effect was 66.6, 55.9, 38, 17.2, and 12.3% on days 1, 7, 14, 21, and 28, respectively. At each challenge point, the mortality and anti-feeding effects on mosquitoes were significantly different between the control and treated group (p < 0.05). The results indicate that a combination of permethrin and fipronil could be used as an effective mosquito control strategy in dogs and is therefore recommended for use in a dirofilariasis prevention program.

  13. Irritability Levels of Field and Laboratory Population of Culex pipiens Complex in Tehran to Different Groups of Insecticides

    Science.gov (United States)

    Rahimi, Sara; Vatandoost, Hassan; Abai, Mohammad Reza; Raeisi, Ahmad; Hanafi-Bojd, Ahmad Ali; Rafi, Fatemeh

    2016-01-01

    Background: The irritant effect of some insecticides can cause a proportion of mosquitoes to leave the sprayed rooms before acquiring a lethal dose, so the repeated contact al sub-lethal dose may lead to extent the resistance. Methods: Larvae and pupae of Culex pipiens complex were collected in mass from open canals of waste water in capital city Tehran and reared to obtain the first generation at laboratory. Sugar-fed 2–3 days female mosquitoes were used for the experiments and compared with laboratory strain. The irritability tests of insecticides impregnated papers were measured in plastic conical exposure chambers placed which implemented at controlled conditions according to the method described by WHO. Number of take-offs were counted during 15 minutes of exposure time. Results: DDT had the most irritancy effect against field population of Cx. pipiens. DDT, permethrin and deltamethrin was moderately irritable against laboratory strain, whereas, addition to three previous insecticides, malathion, cyfluthrin and propoxur should be also considered as moderately irritable insecticides for field population of. Irritability level of etofenprox, fenithrothion, bendiocarb, and lambdacyhalothrin did not differ from control group. Conclusion: The irritability response of mosquitoes may have a negative impact on control measures. Periodical execution of irritability tests with insecticides that routinely used in vector control program is highly recommended. PMID:27308276

  14. Preparation of Ecofriendly Formulations Containing Biologically Active Monoterpenes with Their Fumigant and Residual Toxicities against Adults of Culex pipiens

    Directory of Open Access Journals (Sweden)

    Mohamed E. I. Badawy

    2016-01-01

    Full Text Available Different mixtures of monoterpenes (ketone, alcohol, and alkene were loaded on paper discs and wax and their knockdown activities were evaluated against Culex pipiens adults. Some individual monoterpenes were also evaluated by residual toxicity technique. Citronella oil as a reference was also loaded separately or in combination with monoterpenes on paper discs and wax. The ketone monoterpenes mixture (camphor, menthone, carvone, and fenchone on paper discs was the most active (KT50 = 17.20 min followed by ketone monoterpenes with citronella oil (KT50 = 20.79 min and citronella oil alone (KT50 = 28.72 min. Wax formulations proved that the ketone and alcohol (geraniol, thymol, and menthol monoterpenes gave the most activity as knockdown (KT50 = 31.79 and 43.39 min, resp.. Alcohol monoterpenes formulation recorded KT50 = 43.39 min. Residual activity of tested individual monoterpenes reported that the menthol was more toxic than camphor and camphene. Generally, this study suggests that the monoterpenes have the properties, which make them used as eco-friendly compounds in the control programs of Cx. pipiens adult. The use of paper discs is more applicable than wax in the adulticidal formulations.

  15. High prevalence and lineage diversity of avian malaria in wild populations of great tits (Parus major and mosquitoes (Culex pipiens.

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    Olivier Glaizot

    Full Text Available Avian malaria studies have taken a prominent place in different aspects of evolutionary ecology. Despite a recent interest in the role of vectors within the complex interaction system of the malaria parasite, they have largely been ignored in most epidemiological studies. Epidemiology of the disease is however strongly related to the vector's ecology and behaviour, and there is a need for basic investigations to obtain a better picture of the natural associations between Plasmodium lineages, vector species and bird hosts. The aim of the present study was to identify the mosquito species involved in the transmission of the haemosporidian parasites Plasmodium spp. in two wild populations of breeding great tits (Parus major in western Switzerland. Additionally, we compared Plasmodium lineages, based on mitochondrial DNA cytochrome b sequences, between the vertebrate and dipteran hosts, and evaluated the prevalence of the parasite in the mosquito populations. Plasmodium spp. were detected in Culex pipiens only, with an overall 6.6% prevalence. Among the six cytochrome b lineages of Plasmodium identified in the mosquitoes, three were also present in great tits. The results provide evidence for the first time that C. pipiens can act as a natural vector of avian malaria in Europe and yield baseline data for future research on the epidemiology of avian malaria in European countries.

  16. High prevalence and lineage diversity of avian malaria in wild populations of great tits (Parus major) and mosquitoes (Culex pipiens).

    Science.gov (United States)

    Glaizot, Olivier; Fumagalli, Luca; Iritano, Katia; Lalubin, Fabrice; Van Rooyen, Juan; Christe, Philippe

    2012-01-01

    Avian malaria studies have taken a prominent place in different aspects of evolutionary ecology. Despite a recent interest in the role of vectors within the complex interaction system of the malaria parasite, they have largely been ignored in most epidemiological studies. Epidemiology of the disease is however strongly related to the vector's ecology and behaviour, and there is a need for basic investigations to obtain a better picture of the natural associations between Plasmodium lineages, vector species and bird hosts. The aim of the present study was to identify the mosquito species involved in the transmission of the haemosporidian parasites Plasmodium spp. in two wild populations of breeding great tits (Parus major) in western Switzerland. Additionally, we compared Plasmodium lineages, based on mitochondrial DNA cytochrome b sequences, between the vertebrate and dipteran hosts, and evaluated the prevalence of the parasite in the mosquito populations. Plasmodium spp. were detected in Culex pipiens only, with an overall 6.6% prevalence. Among the six cytochrome b lineages of Plasmodium identified in the mosquitoes, three were also present in great tits. The results provide evidence for the first time that C. pipiens can act as a natural vector of avian malaria in Europe and yield baseline data for future research on the epidemiology of avian malaria in European countries.

  17. Identification of differentially expressed microRNAs in Culex pipiens and their potential roles in pyrethroid resistance.

    Science.gov (United States)

    Hong, Shanchao; Guo, Qin; Wang, Weijie; Hu, Shengli; Fang, Fujin; Lv, Yuan; Yu, Jing; Zou, Feifei; Lei, Zhentao; Ma, Kai; Ma, Lei; Zhou, Dan; Sun, Yan; Zhang, Donghui; Shen, Bo; Zhu, Changliang

    2014-12-01

    Pyrethroids are the major class of insecticides used for mosquito control. Excessive and improper use of insecticides, however, has resulted in pyrethroid resistance, which has become a major obstacle for mosquito control. The development of pyrethroid resistance is a complex process involving many genes, and information on post-transcription regulation of pyrethroid resistance is lacking. In this study, we extracted RNA from mosquitoes in various life stages (fourth-instar larvae, pupae, male and female adult mosquitoes) from deltamethrin-sensitive (DS) and resistant (DR) strains. Using illumina sequencing, we obtained 13760296 and 12355472 reads for DS-strains and DR-strains, respectively. We identified 100 conserved miRNAs and 42 novel miRNAs derived from 21 miRNA precursors in Culex pipiens. After normalization, we identified 28 differentially expressed miRNAs between the two strains. Additionally, we found that cpp-miR-71 was significant down regulated in female adults from the DR-strain. Based on microinjection and CDC Bottle Bioassay data, we found that cpp-miR-71 may play a contributing role in deltamethrin resistance. The present study provides the firstly large-scale characterization of miRNAs in Cu. pipiens and provides evidence of post-transcription regulation. The differentially expressed miRNAs between the two strains are expected to contribute to the development of pyrethroid resistance. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Toxicity of Amorphigenin from the Seeds of Amorpha fruticosa against the Larvae of Culex pipiens pallens (Diptera: Culicidae

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    Yaping Liang

    2015-02-01

    Full Text Available The larvicidal activity of the crude petroleum ether, ethyl acetate, acetone, chloroform and ethanol extracts of Amorpha fruticosa seeds was individually assayed for toxicity against the early fourth-instar larva of the mosquito, Culex pipiens pallens after 24 h exposure. Of the tested extracts, the ethanol one exhibited the highest larvicidal activity (LC50 = 22.69 mg/L. Amorphigenin (8'-hydroxyrotenone, a rotenoid compound which exhibits a strong larvicidal activity with LC50 and LC90 values of 4.29 and 11.27 mg/L, respectively, was isolated from the ethanol extract by column chromatograpy. Its structure was elucidated by 1H-NMR, UV and IR spectral data. Furthermore, investigation of amorphigenin’s effects on mitochondrial complex I activity and protein synthesis in C. pipiens pallens larvae reveals that amorphigenin decreases mitochondrial complex I activities to 65.73% at 10.45 μmol/L, compared to the control, when NADH were used as the substrate. Meanwhile, amorphigenin at 10.45 μmol/L also caused a 1.98-fold decrease in protein content, compared to the control larvae treated with acetone only.

  19. Irritability Levels of Field and Laboratory Population of Culex pipiens Complex in Tehran to Different Groups of Insecticides

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    Sara Rahimi

    2016-01-01

    Full Text Available Background: The irritant effect of some insecticides can cause a proportion of mosquitoes to leave the sprayed rooms before acquiring a lethal dose, so the repeated contact al sub-lethal dose may lead to extent the resistance.Methods: Larvae and pupae of Culex pipiens complex were collected in mass from open canals of waste water in capital city Tehran and reared to obtain the first generation at laboratory. Sugar-fed 2–3 days female mosquitoes were used for the experiments and compared with laboratory strain. The irritability tests of insecticides impregnated pa­pers were measured in plastic conical exposure chambers placed which implemented at controlled conditions ac­cording  to  the  method  described  by WHO .Number of take-offs were counted during 15  minutes of exposure  time.Results: DDT had the most irritancy effect against field population of Cx. pipiens. DDT, permethrin and deltamethrin was moderately irritable against laboratory strain, whereas, addition to three previous insecticides, malathion, cyfluthrin and propoxur should be also considered as moderately irritable insecticides for field population of. Irritability level of etofenprox, fenithrothion, bendiocarb, and lambdacyhalothrin did not differ from control group.Conclusion: The irritability response of mosquitoes may have a negative impact on control measures. Periodical execution of irritability tests with insecticides that routinely used in vector control program is highly recommended.

  20. Culex pipiens, an experimental efficient vector of West Nile and Rift Valley fever viruses in the Maghreb region.

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    Fadila Amraoui

    Full Text Available West Nile fever (WNF and Rift Valley fever (RVF are emerging diseases causing epidemics outside their natural range of distribution. West Nile virus (WNV circulates widely and harmlessly in the old world among birds as amplifying hosts, and horses and humans as accidental dead-end hosts. Rift Valley fever virus (RVFV re-emerges periodically in Africa causing massive outbreaks. In the Maghreb, eco-climatic and entomologic conditions are favourable for WNV and RVFV emergence. Both viruses are transmitted by mosquitoes belonging to the Culex pipiens complex. We evaluated the ability of different populations of Cx. pipiens from North Africa to transmit WNV and the avirulent RVFV Clone 13 strain. Mosquitoes collected in Algeria, Morocco, and Tunisia during the summer 2010 were experimentally infected with WNV and RVFV Clone 13 strain at titers of 10(7.8 and 10(8.5 plaque forming units/mL, respectively. Disseminated infection and transmission rates were estimated 14-21 days following the exposure to the infectious blood-meal. We show that 14 days after exposure to WNV, all mosquito st developed a high disseminated infection and were able to excrete infectious saliva. However, only 69.2% of mosquito strains developed a disseminated infection with RVFV Clone 13 strain, and among them, 77.8% were able to deliver virus through saliva. Thus, Cx. pipiens from the Maghreb are efficient experimental vectors to transmit WNV and to a lesser extent, RVFV Clone 13 strain. The epidemiologic importance of our findings should be considered in the light of other parameters related to mosquito ecology and biology.

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

    Institute of Scientific and Technical Information of China (English)

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

    2016-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2016-01-01

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

  3. Asymmetric effects of native and exotic invasive shrubs on ecology of the West Nile virus vector Culex pipiens (Diptera: Culicidae).

    Science.gov (United States)

    Gardner, Allison M; Allan, Brian F; Frisbie, Lauren A; Muturi, Ephantus J

    2015-06-16

    Exotic invasive plants alter the structure and function of native ecosystems and may influence the distribution and abundance of arthropod disease vectors by modifying habitat quality. This study investigated how invasive plants alter the ecology of Culex pipiens, an important vector of West Nile virus (WNV) in northeastern and midwestern regions of the United States. Field and laboratory experiments were conducted to test the hypothesis that three native leaf species (Rubus allegheniensis, blackberry; Sambucus canadensis, elderberry; and Amelanchier laevis, serviceberry), and three exotic invasive leaf species (Lonicera maackii, Amur honeysuckle; Elaeagnus umbellata, autumn olive; and Rosa multiflora, multiflora rose) alter Cx. pipiens oviposition site selection, emergence rates, development time, and adult body size. The relative abundance of seven bacterial phyla in infusions of the six leaf species also was determined using quantitative real-time polymerase chain reaction to test the hypothesis that variation in emergence, development, and oviposition site selection is correlated to differences in the diversity and abundance of bacteria associated with different leaf species, important determinants of nutrient quality and availability for mosquito larvae. Leaf detritus from invasive honeysuckle and autumn olive yielded significantly higher adult emergence rates compared to detritus from the remaining leaf species and honeysuckle alleviated the negative effects of intraspecific competition on adult emergence. Conversely, leaves of native blackberry acted as an ecological trap, generating high oviposition but low emergence rates. Variation in bacterial flora associated with different leaf species may explain this asymmetrical production of mosquitoes: emergence rates and oviposition rates were positively correlated to bacterial abundance and diversity, respectively. We conclude that the displacement of native understory plant species by certain invasive shrubs

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

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    Duangkamon Sritabutra

    2013-08-01

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

  5. Larvicidal Activities of Indigenous Bacillus thuringiensis Isolates and Nematode Symbiotic Bacterial Toxins against the Mosquito Vector, Culex pipiens (Diptera: Culicidae

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    Ashraf M Ahmed

    2017-06-01

    Full Text Available Background: The incidence of mosquito-borne diseases and the resistance of mosquitoes to conventional pesticides have recently caused a panic to the authorities in the endemic countries. This study was conducted to identify native larvicidal biopesticides against Culex pipiens for utilization in the battle against mosquito-borne diseases.Methods: Larvicidal activities of new indigenous Bacillus thuringiensis isolates and crude toxin complexes (TCs of two nematode bacterial-symbionts, Photorhabdus luminescens akhurstii (HRM1 and Ph. luminescens akhurstii (HS1 that tested against Cx. pipiens. B. thuringiensis isolates were recovered from different environmental samples in Saudi Arabia, and the entomopathogenic nematodes, Heterorhabditis indica (HRM1 and He. sp (HS1 were iso­lated from Egypt. Larvicidal activities (LC50 and LC95 of the potentially active B. thuringiensis strains or TCs were then evaluated at 24 and 48h post-treatment.Results: Three B. thuringiensis isolates were almost as active as the reference B. thuringiensis israelensis (Bti-H14, and seven isolates were 1.6–5.4 times more toxic than Bti-H14. On the other hand, the TCs of the bacterial sym­bionts, HRM1 and HS1, showed promising larvicidal activities. HS1 showed LC50 of 2.54 folds that of HRM1 at 24h post-treatment. Moreover, histopathological examinations of the HS1-treated larvae showed deformations in midgut epithelial cells at 24h post-treatment.Conclusion: Synergistic activity and molecular characterization of these potentially active biocontrol agents are currently being investigated. These results may lead to the identification of eco-friend mosquito larvicidal product(s that could contribute to the battle against mosquito-borne diseases.

  6. Larvicidal activity of selected plant hydrodistillate extracts against the house mosquito, Culex pipiens, a West Nile virus vector.

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    Cetin, Huseyin; Yanikoglu, Atila; Cilek, James E

    2011-04-01

    The larvicidal activity of hydrodistillate extracts from Chrysanthemum coronarium L., Hypericum scabrum L., Pistacia terebinthus L. subsp. palaestina (Boiss.) Engler, and Vitex agnus castus L. was investigated against the West Nile vector, Culex pipiens L. (Diptera: Culicidae). Yield and identification of the major essential oils from each distillation was determined by GC-MS analyses. The major essential oil component for each plant species was as follows: α-pinene for P. terebinthus palaestina, and H. scabrum (45.3% and 42.3%, respectively), trans-β-caryophyllene for V. agnus castus (22.1%), and borneol for C. coronarium (20.9%). A series of distillate concentrations from these plants (that ranged from 1 ppm to 500 ppm, depending on plant species) were assessed against late third to early fourth C. pipiens larvae at 1, 6, and 24 h posttreatment. In general, larval mortality to water treated with a distillate increased as concentration and exposure time increased. H. scabrum and P. terebinthus palaestina were most effective against the mosquito larvae and both produced 100% mortality at 250 ppm at 24-h continuous exposure compared with the other plant species. Larval toxicity of the distillates at 24 h (LC(50) from most toxic to less toxic) was as follows: P. terebinthus palaestina (59.2 ppm) > H. scabrum (82.2 ppm) > V. agnus castus (83.3 ppm) > C. coronarium (311.2 ppm). But when LC(90) values were compared, relative toxicity ranking changed as follows: H. scabrum (185.9 ppm) > V. agnus castus (220.7 ppm) > P. terebinthus palaestina (260.7 ppm) > C. coronarium (496.3 ppm). Extracts of native Turkish plants continue to provide a wealth of potential sources for biologically active agents that may be applied against arthropod pests of man and animals.

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

    Science.gov (United States)

    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.

  8. Analysis of population structure and insecticide resistance in mosquitoes of the genus Culex, Anopheles and Aedes from different environments of Greece with a history of mosquito borne disease transmission.

    Science.gov (United States)

    Fotakis, Emmanouil A; Chaskopoulou, Alexandra; Grigoraki, Linda; Tsiamantas, Alexandros; Kounadi, Stella; Georgiou, Loukas; Vontas, John

    2017-10-01

    Greece has been recently affected by several mosquito borne diseases with the West Nile Virus (WNV) outbreak in 2010 being one of the largest reported in Europe. Currently at the epicenter of an economic and refugee crisis and visited by over 16 million tourists a year the integrated management of diseases transmitted by mosquitoes is a public health and economic priority. Vector control programs rely mainly on insecticides, however data on insecticide resistance and the mosquito fauna is essential for successful applications. We determined the mosquito species composition and population dynamics in areas of increased vulnerability to vector borne disease transmission, as well as investigated the resistance status of major nuisance and disease vectors to insecticides. High mosquito densities were recorded in Thessaloniki and Evros, with Aedes caspius, a nuisance species, Culex pipiens, a known vector of WNV and Anopheles hyrcanus a potential vector of malaria being among the most prevalent species. Both vector species populations reached their peak in late summer. Aedes albopictus was recorded at high densities in Thessaloniki, but not in Evros. Notably, Cx. pipiens hybrids, which show an opportunistic biting behavior and are suspected to be involved in the transmission of the WNV, were recorded in considerable numbers in Thessaloniki and Attica. Culex pipiens and An. hyrcanus, but not Ae. caspius mosquitoes, showed moderate levels of resistance to deltamethrin. The presence of resistance in areas not exposed to vector control indicates that other factors could be selecting for resistance, i.e. pesticide applications for agriculture. Both L1014F and L101C kdr mutations were detected in Cx. pipiens populations. Anopheles hyrcanus resistance was not associated with mutations at the L1014 site. The Ace-1 mutations conferring insensitivity to organophosphates and carbamates were detected at low frequencies in all Cx. pipiens populations. Increased activity of P450s and

  9. The diapause program impacts renal excretion and molecular expression of aquaporins in the northern house mosquito, Culex pipiens.

    Science.gov (United States)

    Yang, Liu; Denlinger, David L; Piermarini, Peter M

    2016-12-27

    Adult females of the mosquito Culex pipiens entering diapause increase sugar water ingestion and reduce evaporative water loss, but how these attributes of the diapause program impact activity of the renal excretory system remains unknown. Here we compared the renal excretory capacity of diapausing and non-diapausing females, as well as the molecular expression of aquaporin (AQP) genes that encode channels involved in transporting water and/or small metabolites. Baseline urine excretion rates in diapausing mosquitoes were higher than in those of their non-diapausing counterparts, possibly a consequence of the intense sugar feeding associated with diapause. But, diapausing mosquitoes exhibited a much lower capacity for diuresis than non-diapausing mosquitoes. The suppressed diuretic capacity likely reflects reduced investment in the energetically-expensive post-prandial diuresis, an event not observed in diapausing mosquitoes. The mRNA expression levels of two genes encoding AQPs, Eglp1 and Aqp12L, in diapausing mosquitoes were down-regulated (on day 14) and up-regulated (on both days 3 and 14), respectively, in whole body samples. These changes were not evident in the excretory system (i.e., Malpighian tubules and hindgut), which showed no differential expression of AQPs as a function of diapause. Several AQP mRNAs were, however, differentially expressed in the midgut, ovaries, and abdominal body wall of diapausing mosquitoes, suggesting that AQPs in these tissues may be playing important non-excretory roles that are unique to diapause physiology.

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

    Science.gov (United States)

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

    2012-01-01

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

  11. REPELLENT EFFECT OF OCIMUM BASILICUM AND GLYCYRRHIZA GLABRA EXTRACTS AGAINST THE MOSQUITO VECTOR, CULEX PIPIENS (DIPTERA: CULICIDAE).

    Science.gov (United States)

    Hassan, Mostafa I; Hammad, Kotb M; Saeed, Saeed M

    2015-08-01

    Essential or volatile oils of plants have been variously reported to have many medicinal applications. Methanol, acetone and petroleum ether extracts of Ocimum basilicum and Glycyrrhiza glabra were screened for their repellency effect against Culex pipiens mosquito. The repellent action of the present plants extracts were varied depending on the solvent used and dose of extract. Methanol extract of O. basilicum exhibited the lowest repellent activity as it recorded 77.4% at 6.7mg/cm2. The petroleum ether and acetone extract of 0. basilicum showed repellency of 98.1 & 84.6% respectively, at dose of 6.7mg/cm2, while methanolic extract of G. glabra recorded 73.8 & 50.3% at dose of 6.7 &1.7mg/cm2 respectively, the petroleum ether and acetone extract of G. glabra showed repellency of 76.3 & 81.6%, respectively at dose of 6.7mg/cm2, compared with the commercial formulation, N.N. diethyl toulamide (DEET) which exhibited 100% repellent action at dose of 1.8mg/cm2, respectively. The results may contribute to design an alternative way to control mosquitoes currently based on applications of synthetic insecticides. These extracts could be developed commercially as an effective personal protection meaure against mosquito bites and thus to control diseases caused by mosquito-borne pathogens.

  12. Effect of environmental temperature on the ability of Culex pipiens (Diptera: Culicidae) to transmit West Nile virus.

    Science.gov (United States)

    Dohm, David J; O'Guinn, Monica L; Turell, Michael J

    2002-01-01

    Environmental temperature can affect the ability of mosquitoes to transmit an arbovirus. However, results of various studies indicate that these effects are not consistent among viruses or mosquito species, and there is no information available on the effect of environmental temperature on the ability of North American mosquito species to transmit West Nile (WN) virus. We evaluated the effect of incubation temperature (18, 20, 26, or 30 degrees C) on the ability of Culex pipiens L. derived from specimens collected during the outbreak in New York in 1999 to transmit a strain of WN virus obtained from a crow that died during this outbreak. Although mosquitoes fed on the same viremic chickens, infection rates were directly related to subsequent incubation temperatures. In mosquitoes held at 30 degrees C, virus was recovered from nearly all mosquitoes tested, disseminated infections were detected as early as 4 d after the infectious blood meal, and >90% of all mosquitoes had a disseminated infection 12 or more days after the infectious blood meal. In contrast, for mosquitoes held at 18 degrees C, disseminated infections were not detected until 25 d after the infectious blood meal, and even after 28 d, <30% contained a disseminated infection. Results for mosquitoes held at 20 and 26 degrees C were intermediate for both infection and dissemination rates. The effect of environmental temperature should to be considered when evaluating the vector competence of these mosquitoes and modeling risk of WN virus transmission in nature.

  13. The role of miR-2∼13∼71 cluster in resistance to deltamethrin in Culex pipiens pallens.

    Science.gov (United States)

    Guo, Qin; Huang, Yun; Zou, Feifei; Liu, Bingqian; Tian, Mengmeng; Ye, Wenyun; Guo, Juxin; Sun, Xueli; Zhou, Dan; Sun, Yan; Ma, Lei; Shen, Bo; Zhu, Changliang

    2017-05-01

    Excessive and continuous application of deltamethrin has resulted in the development of deltamethrin resistance among mosquitoes, which becomes a major obstacle for mosquito control. In a previous study, differentially expressed miRNAs between deltamethrin-susceptible (DS) strain and deltamethrin-resistant (DR) strain using illumina sequencing in Culex pipiens pallens were identified. In this study, we applied RNAi and the Centers for Disease Control and Prevention (CDC) bottle bioassay to investigate the relationship between miR-2∼13∼71 cluster (miR-2, miR-13 and miR-71) and deltamethrin resistance. We used quantitative real-time PCR (qRT-PCR) to measure expression levels of miR-2∼13∼71 clusters. MiR-2∼13∼71 cluster was down regulated in adult female mosquitoes from the DR strain and played important roles in deltamethrin resistance through regulating target genes, CYP9J35 and CYP325BG3. Knocking down CYP9J35 and CYP325BG3 resulted in decreased mortality of DR mosquitoes. This study provides the first evidence that miRNA clusters are associated with deltamethrin resistance in mosquitoes. Moreover, we investigated the regulatory networks formed between miR-2∼13∼71 cluster and its target genes, which provide a better understanding of the mechanism involved in deltamethrin resistance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Evaluation of temephos and chlorpyrifos-methyl against Culex pipiens (Diptera: Culicidae) larvae in septic tanks in Antalya, Turkey.

    Science.gov (United States)

    Cetin, H; Yanikoglu, A; Kocak, O; Cilek, J E

    2006-11-01

    The larvicidal activity of chlorpyrifos-methyl and temephos was evaluated against Culex pipiens L. (Diptera: Culicidae) in septic tanks in Antalya, Turkey. Chlorpyrifos-methyl (Pyrifos MT 25 emulsifiable concentrate [EC] ) was evaluated at application rates of 0.04, 0.08, and 0.12 mg active ingredient (AI)/liter, and temephos (Temeguard 50 EC) was evaluated at 0.02, 0.04, and 0.06 mg (AI)/liter during a 21-d study. Generally, overall larval reduction in septic tanks from single- and multifamily dwellings treated with either larvicide was significantly greater than pretreatment levels and control tanks for the duration of the study. At 14 d posttreatment, duration of control was greatest in multifamily tanks treated with chlorpyrifos-methyl at the highest application rate with similar levels of control through 21 d for single-family dwellings (range 97-100%). Septic tanks from both types of family dwellings treated at the highest application rate of temephos resulted in >90% reduction through day 21 (range 91-100%). Laboratory bioassays of septic tank water treated at field application rates, without daily dilution, revealed that complete larval mortality was achieved for 21 d at each application rate and formulation. It is thought that daily addition of water and organic matter to the septic tanks in the single and multifamily dwellings influenced the duration of effectiveness of the larvicides.

  15. Chemical composition and larvicidal evaluation of Mentha, Salvia, and Melissa essential oils against the West Nile virus mosquito Culex pipiens.

    Science.gov (United States)

    Koliopoulos, George; Pitarokili, Danae; Kioulos, Elias; Michaelakis, Antonios; Tzakou, Olga

    2010-07-01

    The volatile metabolites of wild-growing Mentha spicata, M. longifolia, M. suaveolens, Melissa officinalis, Salvia fruticosa, S. pomifera subsp. calycina, and S. pomifera subsp. pomifera from Greece were determined by gas chromatography and gas chromatography-mass spectrometry. The insecticidal properties of the analyzed essential oils were screened on Culex pipiens larvae. Additionally two of the main components of the essential oils, piperitenone oxide and 1,8-cineole were assayed against C. pipiens in order to define the affiliation between them and the larvicidal properties of the oils. The most effective oils were M. suaveolens (major constituent piperitenone oxide, 62.4%), M. spicata (piperitenone oxide, 35.7% and 1,8-cineole, 14.5%) and M. longifolia--Central Greece (piperitenone oxide, 33.4%; 1,8-cineole, 24.5% and trans-piperitone epoxide, 17.4%), which exhibited LC(50) values ranging from 47.88 to 59.33 mg l(-1). Medium activity revealed the oils of M. officinalis (terpin-4-ol, 15.8%; caryophyllene oxide, 13.2%; sabinene, 12.9%; beta-pinene, 12.1%; and trans-caryophyllene, 10.2%), M. longifolia--Southern Greece (carvone, 54.7% and limonene 20.0%), S. pomifera subsp. pomifera (trans-caryophyllene, 22.5% and trans-thujone, 21.0%), S. pomifera subsp. calycina--West Southern Greece (trans-thujone, 56.1% and 1,8-cineole, 10.4%), and S. fruticosa--population 2 (camphor, 23.1%; alpha-pinene, 12.7%; and borneol, 12.6%), with LC(50) values ranging from 78.28 to 91.45 mg l(-1). S. pomifera subsp. calycina (Central Greece) essential oil (trans-thujone, 26.5% and cis-thujone, 12.0%) presented rather low activity (LC(50) values 140.42 mg l(-1)), while S. fruticosa--population 1 (1,8-cineole, 31.4% and camphor, 22.6%) was the only inactive oil. Additionally, the constituent piperitenone oxide was found to be highly active (LC(50) values 9.95 mg l(-1)), whereas 1,8-cineole revealed no toxicity.

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

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    Suzane Alves dos Santos

    2014-12-01

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

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

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    Raimundo Wagner Souza Aguiar

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

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

    Science.gov (United States)

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

    2015-01-01

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

  19. Effects of gamma radiation on the activity of the mosquito culex pipiens L. II. Effects on the sexual vitality of the mosquito

    OpenAIRE

    El Banby, M. A. [محمد البنبي; Wakid, A. M.; Shoman, A. A.

    1988-01-01

    The effects of 3 gamma doses on the sex vitality of the mosquito Culex pipiens L. were studied after irradiation of the larvae, pupae or newly emerged adults. No significant effect on the sex attraction was obseived when irradiation was done at the larval or adult stages with 40 Gray. However, there was a clear effect of radiation at all doses tested on the attraction of males to females when they were irradiated in the pupal stage. At 80 and 120 Gray, there was a significant decrease, whe...

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

    Science.gov (United States)

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

    2013-09-01

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

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

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    Minghui Zhao

    Full Text Available Acetylcholinesterase resistance has been well documented in many insects, including several mosquito species. We tested the resistance of five wild, Chinese strains of the mosquito Culex pipiens quinquefasciatus to two kinds of pesticides, dichlorvos and propoxur. An acetylcholinesterase gene (ace1 was cloned and sequenced from a pooled sample of mosquitoes from these five strains and the amino acids of five positions were found to vary (V185M, G247S, A328S, A391T, and T682A. Analysis of the correlation between mutation frequencies and resistance levels (LC50 suggests that two point mutations, G247S (r2 = 0.732, P = 0.065 and A328S (r2 = 0.891, P = 0.016, are associated with resistance to propoxur but not to dichlorvos. Although the V185M mutation was not associated with either dichlorvos or propoxur resistance, its RS genotype frequency was correlated with propoxur resistance (r2 = 0.815, P = 0.036. And the HWE test showed the A328S mutation is linked with V185M, also with G247S mutation. This suggested that these three mutations may contribute synergistically to propoxur resistance. The T682A mutation was negatively correlated with propoxur (r2 = 0.788, P = 0.045 resistance. Knowledge of these mutations may help design strategies for managing pesticide resistance in wild mosquito populations.

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

    Science.gov (United States)

    Zhao, Minghui; Dong, Yande; Ran, Xin; Wu, Zhiming; Guo, Xiaoxia; Zhang, Yingmei; Xing, Dan; Yan, Ting; Wang, Gang; Zhu, Xiaojuan; Zhang, Hengduan; Li, Chunxiao; Zhao, Tongyan

    2014-01-01

    Acetylcholinesterase resistance has been well documented in many insects, including several mosquito species. We tested the resistance of five wild, Chinese strains of the mosquito Culex pipiens quinquefasciatus to two kinds of pesticides, dichlorvos and propoxur. An acetylcholinesterase gene (ace1) was cloned and sequenced from a pooled sample of mosquitoes from these five strains and the amino acids of five positions were found to vary (V185M, G247S, A328S, A391T, and T682A). Analysis of the correlation between mutation frequencies and resistance levels (LC50) suggests that two point mutations, G247S (r2 = 0.732, P = 0.065) and A328S (r2 = 0.891, P = 0.016), are associated with resistance to propoxur but not to dichlorvos. Although the V185M mutation was not associated with either dichlorvos or propoxur resistance, its RS genotype frequency was correlated with propoxur resistance (r2 = 0.815, P = 0.036). And the HWE test showed the A328S mutation is linked with V185M, also with G247S mutation. This suggested that these three mutations may contribute synergistically to propoxur resistance. The T682A mutation was negatively correlated with propoxur (r2 = 0.788, P = 0.045) resistance. Knowledge of these mutations may help design strategies for managing pesticide resistance in wild mosquito populations.

  3. Culex Species Mosquitoes and Zika Virus.

    Science.gov (United States)

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

    2016-10-01

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

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

    Directory of Open Access Journals (Sweden)

    M. Deepa

    2014-12-01

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

  5. A shut-down in expression of an insulin-like peptide, ILP-1, halts ovarian maturation during the overwintering diapause of the mosquito Culex pipiens.

    Science.gov (United States)

    Sim, C; Denlinger, D L

    2009-06-01

    Short day-length is used to programme adult diapause in the mosquito, Culex pipiens. The downstream endocrine event that halts ovarian maturation is a shut-down in juvenile hormone (JH) production, and recent evidence suggests that the insulin signalling pathway may be a key upstream player in executing this developmental arrest. Genes encoding insulin-like peptides-1, -2 and -5 were identified in C. pipiens, and we report that transcript levels of insulin-like peptides-1 and -5 were significantly lower in diapausing females than in their nondiapausing counterparts. Genes encoding both insulin-like peptides-1 and -5 were suppressed using RNA interference in mosquitoes programmed for nondiapause, and ovarian maturation was monitored. Knocking down insulin-like peptide-1 with RNAi in nondiapausing mosquitoes resulted in a cessation of ovarian development akin to diapause, and this arrest in development could be reversed with an application of JH. Knocking down insulin-like peptide-5 did not alter ovarian development. These results are consistent with a role for insulin-like peptide-1 in the signalling pathway leading from the perception of short day-lengths to the shut-down in JH production that characterizes adult diapause in C. pipiens.

  6. Experimental transmission of Hepatozoon gracilis (Wenyon, 1909) com. nov., in its natural host the bean skink lizard (Mabuya quinquetaeniata quinquetaeniata) and vector Culex (C.) pipiens (Diptera: Culicidae).

    Science.gov (United States)

    Adham, Fatma K; Gabre, Refaat M; Ayaad, Tahany A; Galal, Fatma H

    2007-12-01

    The bean skink lizard Mabuya quinquetaeniata quinquetaeniata (Family: Scincidae) collected from Abu-Rawash, Giza was infected with the protozoon Hepatozoon gracilis. The mean percent of infection rate all over the year was 12.57% with the highest peak was in October (33%), meanwhile the lowest infection rate was detected in June (2.1%) and no infection was detected in February. Microscopical examination of experimentally infected Culex (C.) pipiens L smears revealed the presence of gamogony and sporogony stages of H. gracilis in their haemoceal. Cx. pipiens was capable to transmit H. gracilis to non-infected M. q. quinquetaeniata under laboratory conditions (21 +/- 1 & 60-70% R.H) after a prepatent period of 32 +/- 1 days from the infective bite. Various developmental schizogony stages were detected both in the lung endothelial cells and liver parenchymal cells. Developmental stages of H. gracilis in both vector or vertebrate host were described. Cx. pipiens was unable to transmit H. gracilis to snake, Psammophis schokari present in the same area of the bean skink lizard.

  7. Cloning and expression of cry2Aa from native Bacillus thuringiensis strain SY49-1 and its insecticidal activity against Culex pipiens (Diptera: Culicidae).

    Science.gov (United States)

    Yilmaz, Semih; Azizoglu, Ugur; Ayvaz, Abdurrahman; Temizgul, Ridvan; Atciyurt, Zehra Büşra; Karabörklü, Salih

    2017-04-01

    Bacillus thuringiensis (Berliner) (Bt) is well known for having toxicity against pest insects because of their ability to form endospores and broad-range activity of their parasporal inclusions. In this study, a new member of cry2A gene from previously characterized native B. thuringiensis SY49-1 strain was cloned, expressed and used for its activity against Culex pipiens (Diptera: Culicidae) larvae. The sequence analysis of the cloned cry2A gene revealed that it encodes a polypeptide of 633 aa residues with 99% identity to Cry2Aa protein with expected molecular weight of 70.7 kDa. Bacillus thuringiensis delta-endotoxin nomenclature committee designed our sequence as Cry2Aa18 being a new member of Bt toxins. Bioassays against last instar larvae of C. pipiens indicated that Cry2Aa18 has considerable toxicity with LC50 of 630 μg ml(-1). In order to prevent the spread of infectious diseases mediated by C. pipiens, this newly characterized cry2Aa18 gene could constitute as an important biological control tool for controlling mosquito larvae living in freshwater systems and can be used as a good alternative for minimizing the use of chemicals. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    Sathantriphop, Sunaiyana; White, Sabrina A; Achee, Nicole L; Sanguanpong, Unchalee; Chareonviriyaphap, Theeraphap

    2014-12-01

    The behavioral responses of colony populations of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus to four essential oils (citronella, hairy basil, catnip, and vetiver), two standard repellents (DEET and picaridin), and two synthetic pyrethroids (deltamethrin and permethrin) were conducted in the laboratory using an excito-repellency test system. Results revealed that Cx. quinquefasciatus and An. minimus exhibited much stronger behavioral responses to all test compounds (65-98% escape for contact, 21.4-94.4% escape for non-contact) compared to Ae. aegypti (3.7-72.2% escape (contact), 0-31.7% (non-contact)) and Ae. albopictus (3.5-94.4% escape (contact), 11.2-63.7% (non-contact)). In brief, essential oil from vetiver elicited the greatest irritant responses in Cx. quinquefasciatus (96.6%) and An. minimus (96.5%) compared to the other compounds tested. The synthetic pyrethroids caused a stronger contact irritant response (65-97.8% escape) than non-contact repellents (0-50.8% escape for non-contact) across all four mosquito species. Picaridin had the least effect on all mosquito species. Findings from the current study continue to support the screening of essential oils from various plant sources for protective properties against field mosquitoes. © 2014 The Society for Vector Ecology.

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

    Science.gov (United States)

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

    2017-01-01

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

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

    Science.gov (United States)

    Amer, Abdelkrim; Mehlhorn, Heinz

    2006-09-01

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

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

    Science.gov (United States)

    Lupi, Eleonora; Hatz, Christoph; Schlagenhauf, Patricia

    2013-01-01

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

  12. Modeling the distribution of the West Nile and Rift Valley Fever vector Culex pipiens in arid and semi-arid regions of the Middle East and North Africa.

    Science.gov (United States)

    Conley, Amy K; Fuller, Douglas O; Haddad, Nabil; Hassan, Ali N; Gad, Adel M; Beier, John C

    2014-06-24

    The Middle East North Africa (MENA) region is under continuous threat of the re-emergence of West Nile virus (WNV) and Rift Valley Fever virus (RVF), two pathogens transmitted by the vector species Culex pipiens. Predicting areas at high risk for disease transmission requires an accurate model of vector distribution, however, most Cx. pipiens distribution modeling has been confined to temperate, forested habitats. Modeling species distributions across a heterogeneous landscape structure requires a flexible modeling method to capture variation in mosquito response to predictors as well as occurrence data points taken from a sufficient range of habitat types. We used presence-only data from Egypt and Lebanon to model the population distribution of Cx. pipiens across a portion of the MENA that also encompasses Jordan, Syria, and Israel. Models were created with a set of environmental predictors including bioclimatic data, human population density, hydrological data, and vegetation indices, and built using maximum entropy (Maxent) and boosted regression tree (BRT) methods. Models were created with and without the inclusion of human population density. Predictions of Maxent and BRT models were strongly correlated in habitats with high probability of occurrence (Pearson's r=0.774, r=0.734), and more moderately correlated when predicting into regions that exceeded the range of the training data (r=0.666,r=0.558). All models agreed in predicting high probability of occupancy around major urban areas, along the banks of the Nile, the valleys of Israel, Lebanon, and Jordan, and southwestern Saudi Arabia. The most powerful predictors of Cx. pipiens habitat were human population density (60.6% Maxent models, 34.9% BRT models) and the seasonality of the enhanced vegetation index (EVI) (44.7% Maxent, 16.3% BRT). Maxent models tended to be dominated by a single predictor. Areas of high probability corresponded with sites of independent surveys or previous disease outbreaks. Cx

  13. Chemical composition and larvicidal activity of essential oil of Origanum majorana (Lamiaceae) cultivated in Morocco against Culex pipiens (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

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

    2014-01-01

    Objective:To evaluate the larvicidal activity of essential oil of Origanum majorana (Lamiaceae) cultivated in Morocco against Culex pipiens (Diptera:Culicidae). Methods: The analysis and the identification of the various constituents of essential oil were carried out by gas chromatography coupled with mass spectrometry. Biological test was performed according to a standard methodology inspired by the World Health Organization protocol with slight modification. Results:This oil mainly consisted of monoterpene and sesquiterpenes. The majority compounds are 4-terpinene (28.96%), γ-terpinene (18.57%), α-terpinene (12.72%) and sabinene (8.02%). The lethal concentrations (LC50 and LC90) measured for the essential oil Origanum majorana, were respectively of the order of 258.71 mg/L and 580.49 mg/L.

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

    OpenAIRE

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

    2014-01-01

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

  15. Whole transcriptome responses among females of the filariasis and arbovirus vector mosquito Culex pipiens implicate TGF-β signaling and chromatin modification as key drivers of diapause induction.

    Science.gov (United States)

    Hickner, Paul V; Mori, Akio; Zeng, Erliang; Tan, John C; Severson, David W

    2015-07-01

    Culex pipiens mosquitoes are important disease vectors inhabiting temperate zones, worldwide. The seasonal reduction in temperature and photoperiod accompanying late summer and early fall prompts female mosquitoes to enter diapause, a stage of developmental arrest and physiological conditioning that enhances survival during the winter months. To investigate the molecular mechanisms underlying diapause induction, we used custom whole transcriptome microarrays to identify differences in gene expression following exposure to nondiapause (long days, 25 °C) and diapause-inducing (short days, 18 °C) environmental conditions. Using a two-way ANOVA, we identified 1130 genes that were differentially expressed. We used the expression of these genes across three time points to construct a gene co-expression network comprising five modules. Genes in modules 1, 2, and 3 were largely up-regulated, while genes in modules 4 and 5 were down-regulated when compared to nondiapause conditions. Pathway enrichment analysis of the network modules revealed some potential regulatory mechanisms driving diapause induction. Module 1 was enriched for genes in the TGF-ß and Wnt signaling pathways; module 2 was enriched for genes involved in insect hormone biosynthesis, specifically, ecdysone synthesis; module 3 was enriched for genes involved in chromatin modification; and module 5 was enriched for genes in the circadian rhythm pathway. Our results suggest that TGF-β signaling and chromatin modification are key drivers for the integration of environmental signals into the diapause induction phase in C. pipiens mosquitoes.

  16. Evaluación de palaemonetes argentinus (Decapoda, Natantia en el control biológico de larvas de Culex pipiens (Diptera, Culicidae en condiciones de laboratorio

    Directory of Open Access Journals (Sweden)

    Giri Federico

    2003-01-01

    Full Text Available The predator-prey relationship of Palaemonetes argentinus Nobili, 1901 and Culex pipiens s.l. larvae was studied under laboratory conditions. The prawns were separated in two groups, isolated and grouped ones. Mosquitoe larvae were offered to prawns in two forms, limited and unlimited offer to both groups. In the first analysis, values of predation did not differ significantly between males and females of P. argentinus. Predation in 24 h was 14,9 ± 4,2 larvae/prawn. A reduction of predation was observed with unlimited offer for the same hour, during all the experiment. Predation with unlimited offer was higher on the first day than on the second, but returned to high values on the third day, for both groups. In the grouped experiment, predation with limited offer was total on the first days, decreasing to the last day. As a result, P. argentinus was considered an efficient predator of C. pipiens s.l. larvae under laboratory conditions.

  17. Essential oils of indigenous in Greece six Juniperus taxa: chemical composition and larvicidal activity against the West Nile virus vector Culex pipiens.

    Science.gov (United States)

    Vourlioti-Arapi, F; Michaelakis, A; Evergetis, E; Koliopoulos, G; Haroutounian, S A

    2012-05-01

    The chemical composition of 14 essential oils (EOs), obtained from various parts (leaves, fruits, wood) of the six indigenous in Greece Juniperus family taxa, was determined by GC and GC/MS analysis. The insecticidal properties of these EOs were evaluated against Culex pipiens L. larvae of 3rd and early 4th instars, in order to delineate the relationship between the phytochemical content of the EOs and their larvicidal activities. The analytical data indicated that the EOs mainly consisted of monoterpenes, mostly cyclic and only occasionally aliphatic, and to a lesser percent, of diterpenes. The larvicidal bioassays against C. pipiens larvae revealed that the most active EO was derived from the wood of Juniperus drupacea and contains mainly non-oxygenated monoterpenes and a significant amount of diterpenes, displaying the highest chemodiversity. Its initial LC(50) value was 26.47 mg L(-1). On the contrary, the EO isolated from J. phoenicea berries, which consisted of monoterpenes (non-oxygenated, cyclic), was the less active displaying an LC(50) value of 96.69 mg L(-1). In respect to the contained phytochemicals, myrcene was assayed as the most toxic, displaying an LC(50) value of 33.83 mg L(-1), while the four isomers of pinene abundant in all EOs were less active exhibiting LC(50) values ranging from 70.40 to 94.88 mg L(-1). Results herein reveal that the EOs isolated from the studied Juniperus family taxa represent an inexpensive source of natural mosquito control mixtures.

  18. Evaluation of halofenozide against prey mosquito larvae Culex pipiens and the predator fish Gambusia affinis: impact on growth and enzymatic activities.

    Science.gov (United States)

    Soltani, N; Chouahda, S; Smagghe, G

    2008-01-01

    Culex pipiens (Diptera: Culicidae) is the most widely distributed mosquito species in Algeria and many other countries in the world. Mosquitoes are generally controlled by conventional insecticides but these may pose strong secondary effects on the environment. In this context, the insect growth regulators (IGRs) have shown promise in controlling pest insects. Halofenozide (23% EC) is a novel IGRs belonging to the class of non-steroidal ecdysone agonists, and it was found toxic for larvae of C. pipiens. In addition biological methods constitute an alternative to chemical control. Several fish species have been tested against mosquitoes, and Gambusia affinis was found very efficient. In the present study we evaluated the impact of this new potent insecticide (halofenozide) on growth and metric indexes in the larvivorous fish G. affinis under laboratory conditions. In addition, the effects were evaluated on the enzymatic activities of acetyl cholinesterase (AChE) and glutathione S-transferase (GST). The insecticide was added in water at two concentrations (12.6 and 28.6 microg/L) corresponding to the LC50 and LC90 obtained against fourth instar larvae of C. pipiens, and adult females of G. affinis were exposed to halofenozide for 30 days. At different exposure times we measured the length and weight of fishes, the index of condition (K), the gonado-somatic ratio (GSR) and the hepato-somatic ratio (HSR). The results showed that halofenozide had no significant (p>0.05) effects on growth, metric indexes and AChE activities. However, treatment caused a significant induction (p<0.05) in GST activities at days 15 and 30 with the highest dose. Our results indicate that this ecdysteroid agonist presented only minor secondary effects on the non-target fish species, and so it has potential for controlling of mosquitoes in an integrated manner.

  19. Cloning and Overexpression of CYP6F1, a Cytochrome P450 Gene,from Deltamethrin-resistant Culex pipiens pallens

    Institute of Scientific and Technical Information of China (English)

    Mao-Qing GONG; Chang-Liang ZHU; Yan GU; Xiao-Bang HU; Yan SUN; Lei MA; Xiu-Lan LI; Li-Xin SUN; Jing SUN; Jin QIAN

    2005-01-01

    CYP6F1 (GenBank/EMBL accession No. AY662654), a novel gene with a complete encoding sequence in the cytochrome P450 family 6, was cloned and sequenced from deltamethrin-resistant 4th instar larvae of Culex pipiens pallens. The cDNA sequence of CYP6F1 has an open reading frame of 1527bp, which encodes a putative protein of 508 amino acid residues. The deduced amino acid sequence of CYP6F1 indicated that the encoded P450 has conserved domains of a putative membrane-anchoring signal,putative reductase-binding sites, a typical heme-binding site, an ETLR motif and substrate recognition sites.Semi-quantitative RT-PCR analysis indicated that the CYP6F1 gene was expressed to a greater extent in the deltamethrin-resistant strain than in the susceptible strain of Cx. pipiens pallens. The expression levels of the CYP6F1 gene in the deltamethrin-resistant 1 st, 2nd, 3rd, 4th instar larvae and adult female mosquitoes differed, with highest expression levels in the 4th instar larvae. In addition, the CYP6F1 gene was stably expressed in mosquito C6/36 cells, and the expected 61.2 kDa band was identified by Western blotting. The cells transfected with CYP6F1 had an increased resistance to deltamethrin as compared with control cells.These results indicate that CYP6F1 is expressed at higher levels in the deltamethrin-resistant strain, and may confer some insecticide resistance in Cx. pipiens pallens.

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

    Science.gov (United States)

    Van Dam, A R; Walton, W E

    2008-12-01

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

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

    Science.gov (United States)

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

    2008-04-01

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

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

    Science.gov (United States)

    Amer, Abdelkrim; Mehlhorn, Heinz

    2006-09-01

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

  3. Cytoplasmic Incompatibility as a Means of Controlling Culex pipiens quinquefasciatus Mosquito in the Islands of the South-Western Indian Ocean

    Science.gov (United States)

    Atyame, Célestine M.; Pasteur, Nicole; Dumas, Emilie; Tortosa, Pablo; Tantely, Michaël Luciano; Pocquet, Nicolas; Licciardi, Séverine; Bheecarry, Ambicadutt; Zumbo, Betty; Weill, Mylène; Duron, Olivier

    2011-01-01

    The use of the bacterium Wolbachia is an attractive alternative method to control vector populations. In mosquitoes, as in members of the Culex pipiens complex, Wolbachia induces a form of embryonic lethality called cytoplasmic incompatibility, a sperm-egg incompatibility occurring when infected males mate either with uninfected females or with females infected with incompatible Wolbachia strain(s). Here we explore the feasibility of the Incompatible Insect Technique (IIT), a species-specific control approach in which field females are sterilized by inundative releases of incompatible males. We show that the Wolbachia wPip(Is) strain, naturally infecting Cx. p. pipiens mosquitoes from Turkey, is a good candidate to control Cx. p. quinquefasciatus populations on four islands of the south-western Indian Ocean (La Réunion, Mauritius, Grande Glorieuse and Mayotte). The wPip(Is) strain was introduced into the nuclear background of Cx. p. quinquefasciatus mosquitoes from La Réunion, leading to the LR[wPip(Is)] line. Total embryonic lethality was observed in crosses between LR[wPip(Is)] males and all tested field females from the four islands. Interestingly, most crosses involving LR[wPip(Is)] females and field males were also incompatible, which is expected to reduce the impact of any accidental release of LR[wPip(Is)] females. Cage experiments demonstrate that LR[wPip(Is)] males are equally competitive with La Réunion males resulting in demographic crash when LR[wPip(Is)] males were introduced into La Réunion laboratory cages. These results, together with the geographic isolation of the four south-western Indian Ocean islands and their limited land area, support the feasibility of an IIT program using LR[wPip(Is)] males and stimulate the implementation of field tests for a Cx. p. quinquefasciatus control strategy on these islands. PMID:22206033

  4. Larvicidal, Biological and Genotoxic Effects, and Temperature-Toxicity Relationship of Some Leaf Extracts of Nerium oleander (Apocynaceae on Culex pipiens (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Shaurub H El-Sayed

    2015-10-01

    Full Text Available  Background: The present study was undertaken to study the larvicidal activity of different extracts of Nerium ole­ander leaves, and post-treatment temperature- toxicity relationship of these extracts against Culex pipiens. Further, the most potent extract was used to evaluate its biological and genotoxic activities. Methods: Crude extracts of N. oleander leaves were prepared using water, chloroform, acetone and diethyl ether as solvents. Extraction was carried out using soxhlet apparatus. Bioassay test was carried out on the larvae, and the LC50 of each extract was determined. Thus, newly hatched first instar larvae were treated, and the mortality count was recorded daily till pupation (accumulated mortality. The LC50 of diethyl ether extract, as the most potent ex­tract, was used for the further biological and genotoxic studies. Results: The results obtained indicated that diethyl ether extract of N. oleander leaves was the most potent extract, with LC50 of 10500 mg/l. The toxicity of the four extracts, using the LC50, at 10 °C was higher than that at 35 °C. The LC50 of diethyl ether extract significantly decreased the larval duration, pupal duration, percentage of pupation, percentage of adult emergence, longevity of females, fecundity, and oviposition activity index, whereas the growth index and the percentage of development per day of larvae and pupae were significantly increased compared to non-treated insects. Moreover, treatment with this extract induced significant dominant lethality in both male and female adults.  Conclusion: It appears that diethyl ether extract of N. oleander leaves is potential control agent to Cx. pipiens

  5. Early warning of West Nile virus mosquito vector: climate and land use models successfully explain phenology and abundance of Culex pipiens mosquitoes in north-western Italy.

    Science.gov (United States)

    Rosà, Roberto; Marini, Giovanni; Bolzoni, Luca; Neteler, Markus; Metz, Markus; Delucchi, Luca; Chadwick, Elizabeth A; Balbo, Luca; Mosca, Andrea; Giacobini, Mario; Bertolotti, Luigi; Rizzoli, Annapaola

    2014-06-12

    West Nile Virus (WNV) is an emerging global health threat. Transmission risk is strongly related to the abundance of mosquito vectors, typically Culex pipiens in Europe. Early-warning predictors of mosquito population dynamics would therefore help guide entomological surveillance and thereby facilitate early warnings of transmission risk. We analysed an 11-year time series (2001 to 2011) of Cx. pipiens mosquito captures from the Piedmont region of north-western Italy to determine the principal drivers of mosquito population dynamics. Linear mixed models were implemented to examine the relationship between Cx. pipiens population dynamics and environmental predictors including temperature, precipitation, Normalized Difference Water Index (NDWI) and the proximity of mosquito traps to urban areas and rice fields. Warm temperatures early in the year were associated with an earlier start to the mosquito season and increased season length, and later in the year, with decreased abundance. Early precipitation delayed the start and shortened the length of the mosquito season, but increased total abundance. Conversely, precipitation later in the year was associated with a longer season. Finally, higher NDWI early in the year was associated with an earlier start to the season and increased season length, but was not associated with abundance. Proximity to rice fields predicted higher total abundance when included in some models, but was not a significant predictor of phenology. Proximity to urban areas was not a significant predictor in any of our models. Predicted variations in start of the season and season length ranged from one to three weeks, across the measured range of variables. Predicted mosquito abundance was highly variable, with numbers in excess of 1000 per trap per year when late season temperatures were low (average 21°C) to only 150 when late season temperatures were high (average 30°C). Climate data collected early in the year, in conjunction with local land

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

    Science.gov (United States)

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

    2010-10-01

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

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

    Directory of Open Access Journals (Sweden)

    S Swathi

    2010-01-01

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

  8. Potential of biologically active plant oils to control mosquito larvae (Culex pipiens, Diptera: Culicidae from an egyptian locality Potencial de óleos de plantas biologicamente ativos para o controle da larva do mosquito Culex pipiens (Diptera: Culicidae de localidade egípcia

    Directory of Open Access Journals (Sweden)

    Hanem Fathy Khater

    2008-04-01

    Full Text Available The insecticidal effect of six commercially available plant oils was tested against 4th larval instars of Culex pipiens. Larvae were originally collected from Meit El-Attar, Qalyubia Governorate, Egypt, and then reared in the laboratory until F1 generation. The LC50 values were 32.42, 47.17, 71.37, 83.36, 86.06, and 152.94 ppm for fenugreek (Trigonella foenum-grecum, earth almond (Cyperus esculentus, mustard (Brassica compestris, olibanum (Boswellia serrata, rocket (Eruca sativa, and parsley (Carum ptroselinum, respectively. The tested oils altered some biological aspects of C. pipiens, for instance, developmental periods, pupation rates, and adult emergences. The lowest concentrations of olibanum and fenugreek oils caused remarkable prolongation of larval and pupal durations. Data also showed that the increase of concentrations was directly proportional to reduction in pupation rates and adult emergences. Remarkable decrease in pupation rate was achieved by mustard oil at 1000 ppm. Adult emergence was suppressed by earth almond and fenugreek oils at 25 ppm. In addition, the tested plant oils exhibited various morphological abnormalities on larvae, pupae, and adult stages. Consequently, fenugreek was the most potent oil and the major cause of malformation of both larval and pupal stages. Potency of the applied plant oils provided an excellent potential for controlling C. pipiens.O efeito inseticida de seis óleos de plantas comercialmente disponíveis foi testado contra larvas de 4ºinstar de Culex pipiens. Larvas foram coletadas originalmente de Meit El-Attar, Qalyubia Governorate, Egito e então cultivadas no laboratório até a geração F1. Os valores LC50 foram 32,42, 47,17, 71,37, 83,36, 86,06 e 152,94 ppm para o feno grego (Trigonella foenum-grecum, amêndoa da terra (Cyperus esculentus, mostarda (Brassica compestris, olíbano (Boswellia serrata, rocket (Eruca sativa e salsa (Carum ptroselium, respectivamente. Os óleos testados alteraram

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

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    Hasan Boesri

    2009-12-01

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

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

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    Mithilesh eKajla

    2016-01-01

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

  11. Influence of warming tendency on Culex pipiens population abundance and on the probability of West Nile fever outbreaks (Israeli Case Study: 2001-2005).

    Science.gov (United States)

    Paz, Shlomit; Albersheim, Iris

    2008-03-01

    Climate change and West Nile fever (WNV) are both subjects of global importance. Many mosquitoes and the diseases they carry, including West Nile virus (WNV), are sensitive to temperature increase. The current study analyzes the lag correlations between weather conditions (especially air temperature) and 1) Culex pipiens mosquito population abundance, and 2) WNF frequency in humans, between 2001 and 2005 in Israel. These 5 years follow a long period with a documented tendency for temperature increase in the hot season in the country. Monthly anomalies of minimum and maximum temperatures, relative seasonal rainfall contribution, mosquito samplings (hazard level), and WNF cases (hospital admission dates and patients' addresses) were analyzed. Logistic regression was calculated between the climatic data and the mosquito samples, as Spearman correlations and Pearson cross-correlations were calculated between daily temperature values (or daily precipitation amounts) and the hospital admission dates. It was found that the disease appearance reflects the population distribution, while the risk tends to escalate around the metropolis characterized by an urban heat island. Positive anomalies of the temperature during the study period appear to have facilitated the mosquito abundance and, consequently, the disease emergence in humans. An important finding is the potential influence of extreme heat in the early spring on the vector population increase and on the disease's appearance weeks later. Awareness of such situations at the beginning of the spring may help authorities to reduce the disease risk before it becomes a real danger.

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

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    Jairo Campos

    2003-08-01

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

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

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    Arshed Iqbal Dar

    2013-02-01

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

  14. Report on the surveillance of insecticidal resistance of Culex pipiens pallens in Hanzhuang%微山湖区韩庄镇淡色库蚊抗药性现状监测报告

    Institute of Scientific and Technical Information of China (English)

    赵方明; 杨秋兰

    2011-01-01

    Culex pipiens pallens was collected from the Weishan Lake district and its insecticidal resistance was measured using a standard WHO bioassay. Cx. Pipiens pallens of Hanzhuang was resistant to five insecticides to some degree. The LC50 of Cx. Pipiens pallens to propoxur, DDVP, acetofenate, deltamethrin, and cypermethrin was 0. 474 1, 1. 401 2, 0. 242 0, 0. 003 4, and 0. 004 1 mg · L-1 , respectively. Cx. Pipiens pallens was most resistant to synthetic py-rethroid pesticides.%采用WHO生物测试法,测定了微山湖区韩庄镇淡色库蚊幼虫对常用杀虫剂的抗性水平.结果 显示韩庄镇淡色库蚊幼虫对残杀威、DDVP、三氯杀虫酯、溴氰菊酯、氯氰菊酯等5种常用杀虫剂的LC5.分别为0.474 1、1.401 2、0.242 0、0.003 4和0.004 1 mg· L-1,以菊酯类杀虫剂抗性最高.

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

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    Campos Jairo

    2003-01-01

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

  16. Molecular structure of the prothoracicotropic hormone gene in the northern house mosquito, Culex pipiens, and its expression analysis in association with diapause and blood feeding.

    Science.gov (United States)

    Zhang, Q; Denlinger, D L

    2011-04-01

    We cloned the gene that encodes prothoracicotropic hormone (PTTH) in the northern house mosquito, Culex pipiens, and investigated its expression profile in short-day (diapause-destined) and long-day (nondiapause-destined) individuals from the fourth-instar larval stage to 2 months of adulthood, as well as after a blood meal. The deduced C. pipiens PTTH (Cupip-PTTH) amino acid sequence contains seven cysteines with a specific spacing pattern. Sequence alignment suggests that Cupip-PTTH is 23% identical to Drosophila melanogaster PTTH, but is ≥59% identical to the PTTHs of other mosquitoes. Cupip-PTTH has structural characteristics similar to those of Bombyx mori PTTH and some vertebrate nerve growth factors with cysteine-knot motifs. PTTH transcripts exhibit a daily cycling profile during the final (fourth) larval instar, with peak abundance occurring late in the scotophase. The fourth-larval instar stage is one day longer in short-day larvae than in long-day larvae, resulting in larger larvae and adults. This additional day of larval development is associated with one extra PTTH cycle. No cycling was observed in pupae, but PTTH transcripts were slightly higher in short-day pupae than in long-day pupae throughout much of the pupal stage. PTTH expression persisted at a nearly constant level in diapausing adult females for the first month but then dropped by ∼50%, while expression decreased at the beginning of adulthood in nondiapausing females and then remained at a low level as long as the females were denied a blood meal. However, when nondiapausing females were offered a blood meal, PTTH transcripts rose approximately 7 fold in 2 h and remained elevated for 24 h. A few diapausing females (∼10%) will take a blood meal when placed in close proximity to a host, but much of the blood is ejected and such meals do not result in mature eggs. Yet, elevated PTTH mRNA expression was also observed in diapausing females that were force fed. Our results thus point to

  17. Vector competence of Aedes aegypti (L.) and Culex quinquefasciatus (Say) for Dirofilaria immitis (Leidy).

    Science.gov (United States)

    Tiawsirisup, Sonthaya; Nithiuthai, Suwannee

    2006-01-01

    This study was performed to examine the vector competence of Aedes aegypti and Culex quinquefasciatus for Dirofilaria immitis. Eleven individual experiments were conducted in this study. Nonthaburi and Udon Thani strains of Ae. aegypti were allowed to feed on infected dogs that had 5,750 and 4,600 microfilariae (mW) per ml of blood, respectively. Three groups of Bangkok-strain Cx. quinquefasciatus were allowed to feed on dogs that had 4,800, 5,200, and 5,850 mf per ml of blood. Six groups of Liverpool-strain Ae. aegypti were allowed to feed on dogs with 1,650, 1,950, 3,350, 9,000, 9,250, and 11,550 mf per ml of blood. Three to 4% of Nonthaburi-strain, and 0-6% of Udon Thani-strain Ae. aegypti became infected and had infective-stage larvae (L3) of D. immitis in their probosces. Zero to 1 and 7% of Bangkok-strain Cx. quinquefasciatus had L3 in their probosces after taking blood meals with 4,800 and 5,850 mf per ml of blood, respectively. The percent-infected Liverpool-strain Ae. aegypti with L3 in their probosces were 3-12, 0-12, 10, 16, 7-19, and 0-21 after taking blood meals with 1,650, 1,950, 3,350, 9,000, 9,250, and 11,550 mf per ml of blood, respectively, when tested at different post-blood-feeding days. This study showed both Ae. aegypti and Cx. quinquefasciatus from Thailand can become vectors for D. immitis; however, Liverpool-strain Ae. aegypti are more likely to be competent vectors for D. immitis than Ae. aegypti and Cx. quinquefasciatus from Thailand. The percent infection rates of Ae. aegypti and Cx. quinquefasciatus with D. immitis in the field in Thailand need to be investigated, to confirm the role of these mosquitoes in the life cycle of D. immitis in nature.

  18. Noncoding Subgenomic Flavivirus RNA Is Processed by the Mosquito RNA Interference Machinery and Determines West Nile Virus Transmission by Culex pipiens Mosquitoes.

    Science.gov (United States)

    Göertz, G P; Fros, J J; Miesen, P; Vogels, C B F; van der Bent, M L; Geertsema, C; Koenraadt, C J M; van Rij, R P; van Oers, M M; Pijlman, G P

    2016-11-15

    Flaviviruses, such as Zika virus, yellow fever virus, dengue virus, and West Nile virus (WNV), are a serious concern for human health. Flaviviruses produce an abundant noncoding subgenomic flavivirus RNA (sfRNA) in infected cells. sfRNA results from stalling of the host 5'-3' exoribonuclease XRN1/Pacman on conserved RNA structures in the 3' untranslated region (UTR) of the viral genomic RNA. sfRNA production is conserved in insect-specific, mosquito-borne, and tick-borne flaviviruses and flaviviruses with no known vector, suggesting a pivotal role for sfRNA in the flavivirus life cycle. Here, we investigated the function of sfRNA during WNV infection of Culex pipiens mosquitoes and evaluated its role in determining vector competence. An sfRNA1-deficient WNV was generated that displayed growth kinetics similar to those of wild-type WNV in both RNA interference (RNAi)-competent and -compromised mosquito cell lines. Small-RNA deep sequencing of WNV-infected mosquitoes indicated an active small interfering RNA (siRNA)-based antiviral response for both the wild-type and sfRNA1-deficient viruses. Additionally, we provide the first evidence that sfRNA is an RNAi substrate in vivo Two reproducible small-RNA hot spots within the 3' UTR/sfRNA of the wild-type virus mapped to RNA stem-loops SL-III and 3' SL, which stick out of the three-dimensional (3D) sfRNA structure model. Importantly, we demonstrate that sfRNA-deficient WNV displays significantly decreased infection and transmission rates in vivo when administered via the blood meal. Finally, we show that transmission and infection rates are not affected by sfRNA after intrathoracic injection, thereby identifying sfRNA as a key driver to overcome the mosquito midgut infection barrier. This is the first report to describe a key biological function of sfRNA for flavivirus infection of the arthropod vector, providing an explanation for the strict conservation of sfRNA production. Understanding the flavivirus transmission

  19. Bioactivity of Dianthus caryophyllus, Lepidium sativum, Pimpinella anisum, and Illicium verum essential oils and their major components against the West Nile vector Culex pipiens.

    Science.gov (United States)

    Kimbaris, Athanasios C; Koliopoulos, George; Michaelakis, Antonios; Konstantopoulou, Maria A

    2012-12-01

    Mosquitoes constitute a severe health problem in many areas all over the world. There are many regions of the tropics and subtropics where mosquitoes are one of the main reasons for inhibiting the economic upgrade. Except nuisance, their medical importance is another matter of attention since mosquitoes are vectors for a wide variety of vector-borne diseases. Due to disadvantages of currently used chemical control methods, it is unavoidable to search for eco-friendly new molecules. We report herein the evaluation of the larvicidal effect exhibited by essential oils of Dianthus caryophyllus, Lepidium sativum, Pimpinella anisum, and Illicium verum against late third to early fourth instar mosquito larvae of Culex pipiens. Furthermore, phytochemical analysis of plant samples revealed their major compounds to be β-caryophyllene, eugenol, eucalyptol, α-terpinyl acetate, and (E)-anethole which were also tested for their potential larvicidal activity. For D. caryophyllus and L. sativum, this was the first report on the chemical composition of their essential oils. The essential oils of I. verum and P. anisum demonstrated high larvicidal activity with a LC(50) <18 mg L(-1). The other two essential oils of D. caryophyllus and L. sativum revealed moderate larvicidal activity, displaying a LC(50) value above 50 mg L(-1). Among the pure components, the most toxic were eugenol, (E)-anethole, and α-terpinyl acetate, with LC(50) values 18.28, 16.56, and 23.03 mg L(-1), respectively. Eucalyptol (1,8 cineole) and β-caryophyllene were inactive at concentrations even as high as 100 mg L(-1), showing the least significant activity against mosquito larvae. Results allow some rationalization on the relative importance of the major compounds regarding the larvicidal activity of selected essential oils and their potential use as vector control agents.

  20. Predation and control efficacies of Misgurnus mizolepis (Cypriniformes: Cobitidae) toward Culex pipiens molestus (Diptera: Culicidae) and fish toxicity of temephos in laboratory and septic tank conditions.

    Science.gov (United States)

    Chae, Seong Chun; Kwon, Young Hyun; Min, Kyung Il; Kim, Hyung Soo; Kim, Nam-Jin; Kim, Jun-Ran; Son, Bong Gi; Ahn, Young-Joon

    2014-07-01

    Culex pipiens molestus Forskal (Diptera: Culicidae) is the dominant mosquito species in septic tanks in South Korea. An assessment was made of the biological control potential of mud loaches, Misgurnus mizolepis Günther (Cypriniformes: Cobitidae), toward Cx. p. molestus larvae in laboratory and septic tanks. Results were compared with those of temephos 20% emulsifiable concentrate. In laboratory tests, all mud loaches survived on sedimentation chamber- and effluent chamber-collected water of aerobic septic tanks (ASTs), whereas all mud loaches died within 3-12 h after introduction into sedimentation chamber- and effluent chamber-collected water of anaerobic septic tanks, Gill hyperplasia and hemorrhages at the bases of pectoral fins were detected in all dead mud loaches. These appeared to have been caused by bacterial disease, rather than the physical and chemical characteristics of the septic tank water. A mud loach consumed an average range of 1,072-1,058 larvae of Cx. p. molestus in the AST water at 24 h. At the manufacturer's recommended rate (10 ml/ton) in the AST water, the temephos formulation did not cause fish mortality. In the AST experiment, predation of mosquito larvae by mud loaches at a release rate of one fish per 900 mosquito larvae resulted in complete mosquito control from the third day after treatment throughout the 18-wk survey period, compared with temephos 20% emulsifiable concentrate-treated AST water (reduction rate, 40% at 28 days after treatment). Reasonable mosquito control in aerobic septic tanks can be achieved by mosquito breeding season stocking of a rate of one mud loach per 900 mosquito larvae.

  1. Pyrethroid-resistance is modulated by miR-92a by targeting CpCPR4 in Culex pipiens pallens.

    Science.gov (United States)

    Ma, Kai; Li, Xixi; Hu, Hongxia; Zhou, Dan; Sun, Yan; Ma, Lei; Zhu, Changliang; Shen, Bo

    2017-01-01

    The wide use of pyrethroids has resulted in the emergence and spread of resistance in mosquito populations, which represent a major obstacle in the struggle against vector-borne diseases. Resistance to pyrethroids is a complex genetic phenomenon attributed by polygenetic inheritance. We previously have sequenced and analyzed the miRNA profiles of Culex pipiens pallens. MiR-92a was found to be overexpressed in a deltamethrin-resistant (DR) strain. The association of miR-92a with pyrethroid-resistance was investigated by quantitative reverse transcription PCR (qRT-PCR). Expression levels of miR-92a were 2.72-fold higher in the DR strain than in the deltamethrin-susceptible (DS) strain. Bioinformatic analysis suggested that CpCPR4, a mosquito cuticle gene, is the target of miR-92a. Dual luciferase reporter assays further confirmed that CpCPR4 is modulated by miR-92a through binding to a specific target site in the 3' untranslated region (3' UTR). Microinjection of the miR-92a inhibitor upregulated CpCPR4 expression levels, leading to an increase in the susceptibility of the DR strain in the Centers for Disease Control and Prevention (CDC) bottle bioassay (a surveillance tool for detecting resistance to insecticides in vector populations). Taken together, our findings indicate that miR-92a regulates pyrethroid-resistance through its interaction with CpCPR4. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Mosquito larvicidal, ovicidal, and repellent properties of botanical extracts against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Govindarajan, M; Mathivanan, T; Elumalai, K; Krishnappa, K; Anandan, A

    2011-08-01

    Mosquito-borne diseases have an economic impact, including loss in commercial and labor outputs, particularly in countries with tropical and subtropical climates; however, no part of the world is free from vector-borne diseases. In mosquito control programs, botanical origin may have the potential to be used successfully as eggs, larvae, and adult. The larvicidal, ovicidal, and repellent activities of crude benzene and ethyl acetate extracts of leaf of Ervatamia coronaria and Caesalpinia pulcherrima were assayed for their toxicity against three important vector mosquitoes, viz., Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae). The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in benzene extract of E. coronaria against the larvae of Anopheles Stephensi, Aedes aegypti, and Culex quinquefasciatus with the LC(50) and LC(90) values were 79.08, 89.59, and 96.15 ppm and 150.47, 166.04, and 174.10 ppm, respectively. Mean percent hatchability of the ovicidal activity was observed 48 h posttreatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. The leaf extract of E. coronaria was found to be most effective than Caesalpinia pulcherrima against eggs/egg rafts of three vector mosquitoes. For E. coronaria, the benzene extract exerted 300, 250, and 200 ppm against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus, respectively. The results of the repellent activity of benzene and ethyl acetate extract of E. coronaria and Caesalpinia pulcherrima plants at three different concentrations of 1.0, 2.5, and 5.0 mg/cm(2) were applied on skin of fore arm in man and exposed against adult female mosquitoes. In this observation, these two plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person, and also, the

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

    Science.gov (United States)

    Kovendan, Kalimuthu; Murugan, Kadarkarai; Shanthakumar, Shanmugam Perumal; Vincent, Savariar; Hwang, Jiang-Shiou

    2012-10-01

    Morinda citrifolia leaf extract was tested for larvicidal activity against three medically important mosquito vectors such as malarial vector Anopheles stephensi, dengue vector Aedes aegypti, and filarial vector Culex quinquefasciatus. The plant material was shade dried at room temperature and powdered coarsely. From the leaf, 1-kg powder was macerated with 3.0 L of hexane, chloroform, acetone, methanol, and water sequentially for a period of 72 h each and filtered. The yield of extracts was hexane (13.56 g), chloroform (15.21 g), acetone (12.85 g), methanol (14.76 g), and water (12.92 g), respectively. The extracts were concentrated at reduced temperature on a rotary vacuum evaporator and stored at a temperature of 4°C. The M. citrifolia leaf extract at 200, 300, 400, 500, and 600 ppm caused a significant mortality of three mosquito species. Hexane, chloroform, acetone, and water caused moderate considerable mortality; however, the highest larval mortality was methanolic extract, observed in three mosquito vectors. The larval mortality was observed after 24-h exposure. No mortality was observed in the control. The third larvae of Anopheles stephensi had values of LC(50) = 345.10, 324.26, 299.97, 261.96, and 284.59 ppm and LC(90) = 653.00, 626.58, 571.89, 505.06, and 549.51 ppm, respectively. The Aedes aegypti had values of LC(50) = 361.75, 343.22, 315.40, 277.92, and 306.98 ppm and LC(90) = 687.39, 659.02, 611.35, 568.18, and 613.25 ppm, respectively. The Culex quinquefasciatus had values of LC(50) = 382.96, 369.85, 344.34, 330.42, and 324.64 ppm and LC(90) = 726.18, 706.57, 669.28, 619.63, and 644.47 ppm, respectively. The results of the leaf extract of M. citrifolia are promising as good larvicidal activity against the mosquito vector Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. This is a new eco-friendly approach for the control of vector control programs. Therefore, this study provides first report on the larvicidal activities against three

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

    Science.gov (United States)

    Burke, R; Barrera, R; Lewis, M; Kluchinsky, T; Claborn, D

    2010-06-01

    Adult Aedes aegypti (Linnaeus) (Diptera: Culicidae) were previously recovered from emergence traps on septic tanks in southeastern Puerto Rico. In this study we quantified immature mosquito abundance and its relationship with structural variables of the septic tanks and chemical properties of the water containing raw sewage. A miniaturized floating funnel trap was used to sample 89 septic tanks for larvae in the Puerto Rican community of Playa-Playita. Aedes aegypti larvae were recovered from 18% of the sampled tanks (10.3 larvae per septic tank per day). Larval presence was positively associated with cracking of the septic tank walls and uncovered access ports. Larval abundance was positively associated with cracking of the septic tank walls and larger tank surface areas, and inversely associated with the total dissolved solids (TDS). Culex quinquefasciatus (Say) larvae were also recovered from 74% of the septic tanks (129.6 larvae per septic tank per day). Larval presence was negatively associated with TDS in the water and larval abundance was positively associated with cracking of the septic tank walls. A screened, plastic emergence trap was used to sample 93 septic tanks within the community for Ae. aegypti and Cx. quinquefasciatus adults. Aedes aegypti adults were recovered from 49% of the sampled tanks (8.7 adults per septic tank per day) and Cx. quinquefasciatus adults were recovered from 97% of the sampled tanks (155.5 adults per septic tank per day). Aedes aegypti adult presence was positively associated with cracking, uncapped openings and septic water pH. The Ae. aegypti adult counts were positively associated with cracking and inversely associated with TDS and conductivity. This study marks the first published record of the recovery of Ae. aegypti larvae from holding tanks containing raw sewage in the Caribbean region. Our study indicates that Ae. aegypti larvae are present in sewage water and that septic tanks have at least the potential to maintain

  5. Insecticidal, repellent and oviposition-deterrent activity of selected essential oils against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus.

    Science.gov (United States)

    Prajapati, Veena; Tripathi, A K; Aggarwal, K K; Khanuja, S P S

    2005-11-01

    Essential oils extracted from 10 medicinal plants were evaluated for larvicidal, adulticidal, ovicidal, oviposition-deterrent and repellent activities towards three mosquito species; Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. The essential oils of Juniperus macropoda and Pimpinella anisum were highly effective as both larvicidal and ovicidal. The essential oil of P. anisum showed toxicity against 4th instar larvae of A. stephensi and A. aegypti with equivalent LD95 values of 115.7 microg/ml, whereas it was 149.7 microg/ml against C. quinquefasciatus larvae. Essential oils of Zingiber officinale and Rosmarinus officinalis were found to be ovicidal and repellent, respectively towards the three mosquito species. The essential oil of Cinnamomum zeylanicum resulted into highest repellent (RD95) values of 49.6, 53.9 and 44.2 mg/mat against A. stephensi, A. aegypti and C. quinquefasciatus, respectively apart from oviposition-deterrent potential.

  6. A laboratory study of cyromazine on Aedes aegypti and Culex quinquefasciatus and its activity on selected predators of mosquito larvae.

    Science.gov (United States)

    Nelson, F R; Holloway, D; Mohamed, A K

    1986-09-01

    In a laboratory study, the insect growth regulator, cyromazine, exerted a high level of biological activity on Aedes aegypti and Culex quinquefasciatus treated in the 4th larval instar. At 1.5 and 1.0 ppm this IGR produced 97 and 99% inhibition of emergence in adult Ae. aegypti, respectively. In Cx. quinquefasciatus, there was 99% inhibition at 1 ppm and complete inhibition at 1.5 ppm. The overall pupal mortality was higher than larval or adult stages of both species. This material induced different types of morphogenetic abnormalities in pupae and adults of the 2 species similar to those induced by other IGRs. However, most abnormalities were observed in the pupal stage. Adverse effects were not detected on the 4 mosquito predator species during the acute or posttreatment tests.

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

    Science.gov (United States)

    Phasomkusolsil, Siriporn; Soonwera, Mayura

    2011-09-01

    The essential oils of Cananga odorata (ylang ylang), Citrus sinensis (orange), Cymbopogon citratus (lemongrass), Cymbopogon nardus (citronella grass), Eucalyptus citriodora (eucalyptus), Ocimum basilicum (sweet basil) and Syzygium aromaticum (clove), were tested for their insecticide activity against Aedes aegypti, Culex quinquefasciatus and Anopheles dirus using the WHO standard susceptibility test. These were applied in soybean oil at dose of 1%, 5% and 10% (w/v). C. citratus had the KT, values against the three mosquito species tested but the knockdown rates (at 10, 30 and 60 minutes) were lower than some essential oils. C. citratus oil had high insecticidal activity against Ae. aegypti, Cx. quinquefasciatus and An. dirus, with LC50 values of < 0.1, 2.22 and < 0.1%, respectively. Ten percent C. citratus gave the highest mortality rates (100%) 24 hours after application. This study demonstrates the potential for the essential oil of C. citratus to be used as an insecticide against 3 species of mosquitoes.

  8. 3种仿生电子驱蚊器对淡色库蚊的驱蚊效果观察%Effect of three kinds of electronic mosquito repellents against Culex pipiens pallens

    Institute of Scientific and Technical Information of China (English)

    石华; 钟心霈; 杨振洲

    2012-01-01

    目的 研究市面上流行的3种声波驱蚊器(EMRs)对淡色库蚊的驱散效果.方法 以刺叮率和驱散距离为评定标准.比较是否开启驱蚊器对淡色库蚊刺叮率的影响,以及驱散距离的比较,将结果进行卡方检验,比较均值的差异(P<0.05).结果 是否打开驱蚊器,对淡色库蚊的刺叮率和驱散距离均无统计学差异.结论 市面流行的3种声波驱蚊器对淡色库蚊没有实际驱散效果.%Objective To study the popular three kinds of electronic mosquito repellents ( EMRs ) against Culex pipiens pallens. Methods Taking the biting rate and disperse the distance as the evaluation standard. Comparison of biting rate and disperse the distance whether to open the EMRs. Comparison of many experiments as chi-square test (P<0.05). Results Whether to open the EMRs, the biting rate and disperse the distance showd no statistical difference. Conclusion The popular three kinds of EMRs have no actually disperse effect against Culex pipiens pallens .

  9. How Diverse Detrital Environments Influence Nutrient Stoichiometry between Males and Females of the Co-Occurring Container Mosquitoes Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus

    Science.gov (United States)

    Yee, Donald A.; Kaufman, Michael G.; Ezeakacha, Nnaemeka F.

    2015-01-01

    Allocation patterns of carbon and nitrogen in animals are influenced by food quality and quantity, as well as by inherent metabolic and physiological constraints within organisms. Whole body stoichiometry also may vary between the sexes who differ in development rates and reproductive allocation patterns. In aquatic containers, such as tree holes and tires, detrital inputs, which vary in amounts of carbon and nitrogen, form the basis of the mosquito-dominated food web. Differences in development times and mass between male and female mosquitoes may be the result of different reproductive constraints, which could also influence patterns of nutrient allocation. We examined development time, survival, and adult mass for males and females of three co-occurring species, Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus, across environments with different ratios of animal and leaf detritus. We quantified the contribution of detritus to biomass using stable isotope analysis and measured tissue carbon and nitrogen concentrations among species and between the sexes. Development times were shorter and adults were heavier for Aedes in animal versus leaf-only environments, whereas Culex development times were invariant across detritus types. Aedes displayed similar survival across detritus types whereas C. quinquefasciatus showed decreased survival with increasing leaf detritus. All species had lower values of 15N and 13C in leaf-only detritus compared to animal, however, Aedes generally had lower tissue nitrogen compared to C. quinquefasciatus. There were no differences in the C:N ratio between male and female Aedes, however, Aedes were different than C. quinquefasciatus adults, with male C. quinquefasciatus significantly higher than females. Culex quinquefasciatus was homeostatic across detrital environments. These results allow us to hypothesize an underlying stoichiometric explanation for the variation in performance of different container species under similar

  10. How Diverse Detrital Environments Influence Nutrient Stoichiometry between Males and Females of the Co-Occurring Container Mosquitoes Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus.

    Directory of Open Access Journals (Sweden)

    Donald A Yee

    Full Text Available Allocation patterns of carbon and nitrogen in animals are influenced by food quality and quantity, as well as by inherent metabolic and physiological constraints within organisms. Whole body stoichiometry also may vary between the sexes who differ in development rates and reproductive allocation patterns. In aquatic containers, such as tree holes and tires, detrital inputs, which vary in amounts of carbon and nitrogen, form the basis of the mosquito-dominated food web. Differences in development times and mass between male and female mosquitoes may be the result of different reproductive constraints, which could also influence patterns of nutrient allocation. We examined development time, survival, and adult mass for males and females of three co-occurring species, Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus, across environments with different ratios of animal and leaf detritus. We quantified the contribution of detritus to biomass using stable isotope analysis and measured tissue carbon and nitrogen concentrations among species and between the sexes. Development times were shorter and adults were heavier for Aedes in animal versus leaf-only environments, whereas Culex development times were invariant across detritus types. Aedes displayed similar survival across detritus types whereas C. quinquefasciatus showed decreased survival with increasing leaf detritus. All species had lower values of 15N and 13C in leaf-only detritus compared to animal, however, Aedes generally had lower tissue nitrogen compared to C. quinquefasciatus. There were no differences in the C:N ratio between male and female Aedes, however, Aedes were different than C. quinquefasciatus adults, with male C. quinquefasciatus significantly higher than females. Culex quinquefasciatus was homeostatic across detrital environments. These results allow us to hypothesize an underlying stoichiometric explanation for the variation in performance of different container

  11. How Diverse Detrital Environments Influence Nutrient Stoichiometry between Males and Females of the Co-Occurring Container Mosquitoes Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus.

    Science.gov (United States)

    Yee, Donald A; Kaufman, Michael G; Ezeakacha, Nnaemeka F

    2015-01-01

    Allocation patterns of carbon and nitrogen in animals are influenced by food quality and quantity, as well as by inherent metabolic and physiological constraints within organisms. Whole body stoichiometry also may vary between the sexes who differ in development rates and reproductive allocation patterns. In aquatic containers, such as tree holes and tires, detrital inputs, which vary in amounts of carbon and nitrogen, form the basis of the mosquito-dominated food web. Differences in development times and mass between male and female mosquitoes may be the result of different reproductive constraints, which could also influence patterns of nutrient allocation. We examined development time, survival, and adult mass for males and females of three co-occurring species, Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus, across environments with different ratios of animal and leaf detritus. We quantified the contribution of detritus to biomass using stable isotope analysis and measured tissue carbon and nitrogen concentrations among species and between the sexes. Development times were shorter and adults were heavier for Aedes in animal versus leaf-only environments, whereas Culex development times were invariant across detritus types. Aedes displayed similar survival across detritus types whereas C. quinquefasciatus showed decreased survival with increasing leaf detritus. All species had lower values of 15N and 13C in leaf-only detritus compared to animal, however, Aedes generally had lower tissue nitrogen compared to C. quinquefasciatus. There were no differences in the C:N ratio between male and female Aedes, however, Aedes were different than C. quinquefasciatus adults, with male C. quinquefasciatus significantly higher than females. Culex quinquefasciatus was homeostatic across detrital environments. These results allow us to hypothesize an underlying stoichiometric explanation for the variation in performance of different container species under similar

  12. Host choice and West Nile virus infection rates in blood-fed mosquitoes, including members of the Culex pipiens complex, from Memphis and Shelby County, Tennessee, 2002-2003.

    Science.gov (United States)

    Savage, Harry M; Aggarwal, Deepak; Apperson, Charles S; Katholi, Charles R; Gordon, Emily; Hassan, Hassan K; Anderson, Michael; Charnetzky, Dawn; McMillen, Larry; Unnasch, Emily A; Unnasch, Thomas R

    2007-01-01

    The source of bloodmeals in 2,082 blood-fed mosquitoes collected from February 2002 through December 2003 in Memphis and surrounding areas of Shelby County, Tennessee were determined. Members of the genus Culex and Anopheles quadrimaculatus predominated in the collections. Members of the Cx. pipiens complex and Cx. restuans were found to feed predominately upon avian hosts, though mammalian hosts made up a substantial proportion of the bloodmeals in these species. No significant difference was seen in the host class of bloodmeals in mosquitoes identified as Cx. pipiens pipiens, Cx. p. quinquefasciatus, or hybrids between these two taxa. Anopheles quadrimaculatus and Cx. erraticus fed primarily upon mammalian hosts. Three avian species (the American Robin, the Common Grackle, and the Northern Cardinal) made up the majority of avian-derived bloodmeals, with the American Robin representing the most frequently fed upon avian host. An analysis of these host feeding data using a modification of a transmission model for Eastern Equine encephalitis virus suggested that the American Robin and Common Grackle represented the most important reservoir hosts for West Nile virus. A temporal analysis of the feeding patterns of the dominant Culex species did not support a shift in feeding behavior away from robins to mammals late in the summer. However, a significant degree of temporal variation was noted in the proportion of robin-derived bloodmeals when the data were analyzed by semi-monthly periods throughout the summers of 2002 and 2003. This pattern was consistent with the hypothesis that the mosquitoes were preferentially feeding upon nesting birds.

  13. Culex pipiens pallens resistance to eight insecticides in Shaanxi province%陕西省淡色库蚊抗药性研究

    Institute of Scientific and Technical Information of China (English)

    孙养信; 吕文; 佘建军; 霍丽霞

    2011-01-01

    目的 了解陕西省不同地区淡色库蚊对常用杀虫剂的抗性水平.方法 采用区分剂量法测定淡色库蚊幼虫对4种杀虫剂的24h死亡率;采用半数致死浓度(LC50)法测定淡色库蚊幼虫对8种杀虫剂的LC50.结果 区分剂量法测定结果显示,除榆林市淡色库蚊对氯菊酯属初步抗性群体外,其余均为抗性群体;LC50测定结果显示,5个市的淡色库蚊对高效氯氰菊酯、氯菊酯、溴氰菊酯、氯氰菊酯、DDT、DDVP、双硫磷、残杀威的LC5o分别为0.001 82~0.012 24、0.008 16~0.094 19、0.000 58~0.005 59、0.002 76~0.020 17、0.100 96~1.296 86、0.144 11~0.512 40、0.001 47~0.007 06、0.234 60~1.182 37 mg/L.宝鸡市淡色库蚊的抗药性普遍较高,除溴氰菊酯、氯氰菊酯、双硫磷3种药剂外,其余抗性倍数均在全省最高,而榆林市淡色库蚊的抗药性则普遍较低,除双硫磷和残杀威外,其余各药抗性倍数均为全省最低.结论 蚊虫抗药性的产生与杀虫剂的使用密切相关,在创建卫生城市、卫生县城工作中要科学合理用药,开展抗药性监测,以减缓蚊虫抗药性的产生.%Objective To evaluate the resistance in Culex pipiens pollens to commonly used insecticides in different areas of Shaanxi province. Methods Larval mortality for 4 insecticides and LC? Of 8 insecticides determined via the dosing method and median lethal dose method, respectively. Results The resistance level of Cx. Pipiens pollens in all five areas was high except the population in Yulin city, which had elementary resistance to permethrin. The LC? Values for larvae to p - cypermethrin, permethrin, deltamethrin, cypermethrin, DDT, DDVP, parathion and propoxur were 0.001 82-0.012 24, 0.008 16-0.094 19, 0.000 58-0.005 59, 0.002 76-0.020 17, 0.100 96-1.296 86, 0.144 11-0.512 40, 0.001 47-0.007 06, and 0.234 60-1.182 37 mg/L, respectively. The highest resistance level to all pesticides was found in Baoji city, except for

  14. Cloning and Bioinformatic Analysis of Full-length actin Gene of Culex pipiens pallens%淡色库蚊肌动蛋白全长基因的克隆及生物信息学分析

    Institute of Scientific and Technical Information of China (English)

    王晓宇; 刘虎岐

    2012-01-01

    Culex pipiens pallens is the main carrier of multiple viruses and parasites,and there is close relationship between actin protein and pesticide resistance. Based on gene fragments obtained by resistance-related design reverse transcription and amplification primers, using rapid amplification of cD-NA ends method (RACE), the full length of the gene was amplified from a resistant strain of Culex to analyze their bioinformatic characteristics. The actin gene obtained in Culex pipiens has 1 708 bp coding 377 amino acids. The bioinformatic analysis showed that actin gene was a membrane protein with one helix, one signal peptide cleavage point and twenty-seven phosphorylation sites. The full-length actin gene and biological information lay the foundation for clarifying the resistance mechanism of the actin gene and development of new pesticides.%为阐明肌动蛋白抗药性相关机制及研制新型卫生杀虫剂奠定基础,根据库蚊抗性与敏感品系差异表达的EST片段,设计特异扩增引物,运用RACE技术从淡色库蚊抗性品系中扩增出该抗性相关基因的全长cDNA序列,分析其生物信息学特性.结果表明,获得淡色库蚊肌动蛋白基因cDNA全长1708 bp序列,其编码377个氨基酸;该基因编码的蛋白为膜蛋白,具有27个跨膜螺旋、1个信号肽切割位点、27个磷酸化位点.

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

    OpenAIRE

    Belinato,Thiago Affonso; Martins,Ademir Jesus; Lima, José Bento Pereira; Valle,Denise

    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...

  16. Larvicidal, Ovicidal, and Repellent Activities of Marine Sponge Cliona celata (Grant) Extracts against Culex quinquefasciatus Say and Aedes aegypti L. (Diptera: Culicidae)

    OpenAIRE

    Reegan, Appadurai Daniel; Kinsalin, Arokia Valan; Paulraj, Michael Gabriel; Ignacimuthu,Savarimuthu

    2013-01-01

    Solvent extracts of marine sponge Cliona celata (Grant) were screened for larvicidal, ovicidal, and repellent properties against the filarial vector Culex quinquefasciatus Say and dengue vector Aedes aegypti L. Larvicidal and ovicidal activities of hexane, ethyl acetate, and methanol extracts were tested in four different concentrations ranging as 62.5, 125, 250, and 500 ppm. Among the three solvent extracts of C. celata, methanol extract showed the highest larvicidal activity at 500 ppm agai...

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

    OpenAIRE

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

    2010-01-01

    Mosquitoes are responsible for spread of many diseases than any other group of arthropods. Diseases such as malaria, filariasis, dengue hemorrhagic fever (DHF), and chikunguinya are real threat to mankind. In the present study, ethanolic extracts of leaves of Pongamia pinnata, Coleus forskohlii, and Datura stramonium were evaluated for oviposition deterrent activity against Aedes aegypti and Culex quinquefasciatus. The oviposition deterrent tests of ethanolic extract of Pongamia pinnata, Cole...

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

    Directory of Open Access Journals (Sweden)

    João Zequi

    2011-11-01

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

  19. Larvicidal potentiality, longevity and fecundity inhibitory activities of Bacillus sphaericus (Bs G3-IV on vector mosquitoes, Aedes aegypti and Culex quinquefasciatus

    Directory of Open Access Journals (Sweden)

    Arjunan Nareshkumar

    2012-12-01

    Full Text Available Intervention measures to control the transmission of vector-borne diseases include control of the vector population. In mosquito control, synthetic insecticides used against both the larvae (larvicides and adults (adulticides create numerous problems, such as environmental pollution, insecticide resistance and toxic hazards to humans. In the present study, a bacterial pesticide, Bacillus sphaericus (Bs G3-IV, was used to control the dengue and filarial vectors, Aedes aegypti and Culex quinquefasciatus. Bacillus sphaericus (Bs G3-IV was very effective against Aedes aegypti and Culex quinquefasciatus, showing significant larval mortality. Evaluated lethal concentrations (LC50 and LC90 were age-dependent, with early instars requiring a lower concentration compared with later stages of mosquitoes. Culex quinquefasciatus was more susceptible to Bacillus sphaericus (Bs G3-IV than was Aedes aegypti. Fecundity rate was highly reduced after treatment with different concentrations of Bacillus sphaericus (Bs G3-IV. Larval and pupal longevity both decreased after treatment with Bacillus sphaericus (Bs G3-IV, total number of days was lower in the B. sphaericus treatments compared with the control. Our results show the bacterial pesticide Bacillus sphaericus (Bs G3-IV to be an effective mosquito control agent that can be used for more integrated pest management programs.

  20. Development of Wuchereria bancrofti in Culex pipiens L. (Diptera: Culicidae) exposed in the larval instar to sublethal dosages of insecticides and one insect growth regulator and their influence on reproduction of filaria-infected mosquitoes.

    Science.gov (United States)

    Seif, A I; Husseiny, I M; Soliman, B A; Soliman, M A; el-Kady, M A

    1997-12-01

    The effects of exposure of Culex pipiens larvae to sublethel concentrations of larvicides on uptake, development of Wuchereria bancrofti, survival rate and reproduction of filaria-infected mosquitoes were investigated. Fourth instar larvae of Cx. pipiens were exposed to LC40 of the surfactant Triton X-100, the insect growth regulator DPX alone or combined with LC10 of the surfactant and permethrin alone or combined with LC10 of the surfactant. Adults that survived insecticide treatments and controls were infected by allowing them to feed on microfilaremic volunteers. Significant reduction in the uptake of microfilaria was observed in groups treated with Triton X-100 alone or combined either with permethrin or DPX when compared to control. The overall infection and infective rates were significantly reduced in mosquitoes treated with Triton X-100 either alone or combined with permethrin. Treatment with Triton X-100 and DPX prolonged the extrinsic incubation period (EIP) and retarded the development of filarial larvae, while permethrin either alone or combined with Triton X-100 and DPX combined with Triton X-100 shortened the EIP. All larvicides reduced the number of infective larvae (L3)/mosquito and induced deformities among he different parasite stages, especially in mosquitoes treated with combination of permethrin and Triton X-100 or mixture of DPX and Triton X-100 where 36% and 54.9% respectively of L3S were deformed. In treated mosquitoes, a low percentage of L3S was detected in the head and proboscis region while the majority was trapped in the thoracic region. The survival rates of mosquitoes were reduced in cases treated with permethrin, DPX and Triton X-100 while treatment with mixture of DPX and Triton X-100 induced higher rate of mortalities when compared to control. Egg production of filaria- infected Cx. pipiens was significantly reduced in mosquitoes treated with DPX and Triton X-100. It was observed that the addition of Triton X-100 to DPX or to

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

    Science.gov (United States)

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

    2014-12-01

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

  2. 杀虫剂复配杀灭微山湖区淡色库蚊幼虫效果观察%Effects of compound insecticide on Culex pipiens pallens larvae in Weishan Lake Area

    Institute of Scientific and Technical Information of China (English)

    殷允洪; 程鹏; 王海防

    2011-01-01

    目的 为了延缓和克服蚊虫抗性的发生和发展,更好地选用卫生杀虫剂控制蚊虫,测定了常用杀虫剂复配对微山湖区韩庄镇淡色库蚊幼虫的杀灭作用.方法 采用WHO生物测试法,计算LC50回归方程、增效系数.结果 DDVP+三氯杀虫酯、残杀威+三氯杀虫酯复配共毒系数,分别为164.39~171.08和188.28~221.84,显示出较好的增效作用.DDVP+残杀威复配效果较差.结论 当淡色库蚊产生抗药性后,采用有机磷或氨基甲酸酯类杀虫剂与有机氯类杀虫剂混用的方法,能取得较好效果.%Aim The efficacy of compound insecticides in killing Culex pipiens pallens larvae in Weishan Lake area were bioassayed. Methods WHO standard bioaasay was employed to calculate LC50,regression equation and synertic coefficients of compound insecticides in killing Culex pipiens pallens larvae. Results The synergistic coefficients of DDVP + Acetofenate,propoxur + Acetofenate against mosquitoes were 164.39~171.08 and 188.28~221.84,respectively,showing significant synergism,but the synergism of DDVP + propoxur was low. Conclusion The mixtures of orgnaophosphorus or carbamate insecticides with organochlorine ones may have better control efficacy after the resistance of mosquitoes occurred to insecticides.

  3. Mosquito larvicidal properties of Impatiens balsamina (Balsaminaceae against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Marimuthu Govindarajan

    2014-03-01

    Full Text Available Objective: To assess the larvicidal potential of the crude benzene, chloroform, ethyl acetate and methanol solvent extracts of the medicinal plant Impatiens balsamina against Anopheles stephensi (An. stephensi, Aedes aegypti (Ae. aegypti and Culex quinquefasciatus (Cx. quinquefasciatus. Methods: Twenty five third instar larvae of An. stephensi, Ae. aegypti and Cx. quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using the protocol recommended by WHO. The larval mortality was observed after 24 h of treatment. Results: Among extracts tested, the highest larvicidal activity was observed in leaf methanol extract of Impatiens balsamina against An. stephensi, Ae. aegypti and Cx. quinquefasciatus with the LC50 and LC90 values 98.04, 119.68, 125.06 and 172.93, 210.14, 220.60 mg/L, respectively. Conclusions: From the results it can be concluded that the larvicidal effect of Impatiens balsamina against An. stephensi, Ae. aegypti and Cx. quinquefasciatus make this plant product promising as an alternative to synthetic insecticide in mosquito control programs.

  4. Larvicidal activity of a toxin from the seeds of Jatropha curcas Linn. against Aedes aegypti Linn. and Culex quinquefasciatus Say.

    Science.gov (United States)

    Chanthakan, Nuchsuk; Nuanchawee, Wetprasit; Sittiruk, Roytrakul; Sunanta, Ratanapo

    2012-06-01

    The larvicidal effects of the crude protein extract and purified toxin, Jc-SCRIP, from the seed coat of Jatropha curcas Linn. against the third instar larvae of mosquitoes, Aedes aegypti Linn. and Culex quinquefasciatus Say, were investigated. This test compared the effects of the purified toxin with crude protein extracts from seed kernels of J. curcas and Ricinus communis. At various concentrations of purified toxin and crude protein extract, the larval mortality of both Ae. aegypti and Cx. quinquefasciatus were positively correlated with increased exposure time. The larvae of Cx. quinquefasciatus were more susceptible to the toxin and both extracts than the larvae of Ae. aegypti. After 24 hours of exposure, the extract showed larvicidal activity against Ae. aegypti and Cx. quinquefasciatus with (LC50) values of 3.89 mg/ml and 0.0575 mg/ml, respectively. The toxin, Jc-SCRIP, showed larvicidal activity against Ae. aegypti and Cx. quinquefasciatus with (LC50) values of 1.44 mg/ml and 0.0303 mg/ ml, respectively. These results indicated that the crude protein extract and Jc-SCRIP were more toxic to the third instar larvae of Cx. quinquefasciatus than that of Ae. aegypti. The potent larvicidal activities of the seed coat extract and the Jc-SCRIP toxin from J. curcas suggest that they may be used as bioactive agents to control the mosquito population.

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

    Science.gov (United States)

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

    2015-03-01

    Mosquito control is facing a threat due to the emergence of resistance to synthetic insecticides. Insecticides of botanical origin may serve as suitable alternative biocontrol agents. The present study is to evaluate adulticidal activity of Clausena dentata plant extract against Aedes aegypti and Culex quinquefasciatus mosquitoes. The adult mortality was observed after 24 h of exposure. The highest mortality was found in acetone extracts against Ae. aegypti and Cx. quinquefasciatus with the LC50 and LC90 4.1783 mg/ml (3.8201-7.1026), 9.3884 mg/ml (7. 8258-13.1820) and 4.2451 mg/ml (3.8547-8.0254), 12.3214 mg/ml (10.9287-16.2220), respectively. Smoke toxicity was observed at 10-min interval for 40 min, and the mortality data were recorded. Result shows that Ae. aegypti and Cx. quinquefasciatus are 85 ± 2 and 89 ± 1.5, respectively. A mortality of 100 % was recorded in the commercial mosquito control. These results suggest that the leaf extracts of C. dentata have a potential to be used as an ideal eco-friendly approach for the control of mosquitoes.

  6. Mosquito larvicidal and ovicidal activity of puffer fish extracts against Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Samidurai, Kaliyaperumal; Mathew, Nisha

    2013-03-01

    The extracts of liver (LE), ovary (OE), skin (SE) and muscle (ME) tissues of four species of puffer fishes viz., Arothron hispidus, Lagocephalus inermis, Lagocephalus scleratus and Chelonodon patoca were evaluated against larvae and eggs of three mosquito vectors, Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti. The LC50 values were 1194.26, 1382.73 (LE); 1421.42, 1982.73 (OE); 7116.86, 15038.98 (ME) and 10817.8 ppm (SE) for An. stephensi and Cx. quinquefasciatus respectively for A. hispidus. In the case of L. inermis, the LC50 values were 1163.83, 1556.1 and 2426.38 (LE); 1653.53, 2734.74 (OE); 6067.47 (ME) and 10283.04 ppm (SE) for An. stephensi, Cx. quinquefasciatus and Ae. aegypti respectively. The LC50 values were 1509.98, 1608.69 (LE) and 1414.9, 2278.69 ppm (OE) for An. stephensi and Cx. quinquefasciatus respectively for the extracts of L. scleratus. In the case C. patoca extracts the LC50 values were 1182.29, 1543.00, 2441.03 (LE) and 1076.13, 2582.11 ppm (OE) for An. stephensi, Cx. quinquefasciatus and Ae. aegypti respectively. OE and LE of all puffer fishes exhibited zero percent egg hatchability from 600 to 1000 ppm against eggs of An. stephensi and Cx. quinquefasciatus. This study shows that puffer toxins are effective in killing the larvae and eggs of mosquitoes.

  7. Ovicidal and larvicidal activities of some plant extracts against Aedes aegypti L. and Culex quinquefasciatus Say (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Rajiv Gandhi Munusamy

    2016-06-01

    Full Text Available Objective: To evaluate the ovicidal and larvicidal activities of hexane, chloroform and methanol extracts of Gymnema sylvestre, Scilla peruvina, Rubia cordifolia (R. cordifolia and Elytraria acaulis roots against the eggs and larvae of Aedes aegypti L. (Ae. aegypti and Culex quinquefasciatus Say (Cx. quinquefasciatus at different concentrations of 62.5, 125, 250 and 500 mg/L. Methods: The plant materials were shade dried in the laboratory for one week and then coarsely powdered. The root powder of each plant (500 g was sequentially soaked in hexane, chloroform and methanol for 96 h with intermittent shaking. After 96 h, the solution was filtered and the filtrate was concentrated under reduced pressure by using rotary vacuum evaporator. All the crude extracts thus obtained were stored in air tight glass vials and Petri dishes. Results: The ovicidal activity results showed that the methanol extract of R. cordifolia root was the most potent compared to other with 82.40% and 70.40% activity against the eggs of Cx. quinquefasciatus and Ae. aegypti, respectively, at 500 mg/L concentration similarly, methanol extract of R. cordifolia root also recorded the highest larvicidal activity with LC50 and LC90 values of 95.69, 347.96 mg/L against Cx. quinquefasciatus and 102.23, 350.20 mg/L against Ae. aegypti larvae, respectively. Conculsions: Hence, methanol extract of R. cordifolia root can be probed further for effective biological control of mosquitoes.

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

    Institute of Scientific and Technical Information of China (English)

    Govindarajan M; Mathivanan T; Elumalai K; Krishnappa K; Anandan A

    2011-01-01

    Objective: To determine the ovicidal and repellent activities of methanol leaf extract ofErvatamia coronaria (E. coronaria) and Caesalpinia pulcherrima (C. pulcherrima) against Culex quinquefasciatus (Cx. quinquefasciatus), Aedes aegypti (Ae. aegypti) and Anopheles stephensi (An. stephensi). Methods: The ovicidal activity was determined against three mosquito species at various concentrations ranging from 50-450 ppm under the laboratory conditions. The hatch rates were assessed 48 h after treatment. The repellent efficacy was determined against three mosquito species at three concentrations viz., 1.0, 2.5 and 5.0 mg/cm2 under the laboratory conditions.Results:The crude extract of E. coronaria exerted zero hatchability (100% mortality) at 250, 200 and 150 ppm for Cx. quinquefasciatus, Ae. aegypti and An. stephensi, respectively. The crude extract of C. pulcherrima exerted zero hatchability (100% mortality) at 375, 300 and 225 ppm for Cx. quinquefasciatus, Ae. aegypti and An. Stephensi, respectively. The methanol extract of E. coronaria found to be more repellenct than C. pulcherrima extract. A higher concentration of 5.0 mg/cm2 provided 100% protection up to 150, 180 and 210 min against Cx. quinquefasciatus, Ae.aegypti and An. stephensi, respectively. The results clearly showed that repellent activity was dose dependent. Conclusions: From the results it can be concluded the crude extracts of E. coronaria and C. pulcherrima are an excellent potential for controlling Cx. quinquefasciatus, Ae. aegypti and An. stephensi mosquitoes.

  9. Larvicidal and repellent activity of tetradecanoic acid againstAedes aegypti (Linn.) andCulex quinquefasciatus (Say.) (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Sivakumar R; Jebanesan A; Govindarajan M; Rajasekar P

    2011-01-01

    Objective:To investigate the larvicidal and repellent efficacy of tetradecanoic acid against Aedes aegypti (Ae. aegypti) L. andCulex quinquefasciatus (Cx. quinquefasciatus) Say (Diptera: Culicidae).Methods: Larvicidal efficacy of tetradecanoic acid was tested at various concentrations against the early third instar larvae of Ae. aegypti andCx. quinquefasciatus. The repellent activity was determined against two mosquito species at three concentrations viz.,1.0,2.5 and5.0 ppm under the laboratory conditions.Results: The tetradecanoic acid was found to be more effective againstCx. quinquefasciatus thanAe. aegypti larvae. TheLC50values were14.08 ppm and25.10 ppm, respectively. Tetradecanoic acid showed lesser repellency againstAe. aegypti andCx. quinquefasciatus. The highest repellency was observed in higher concentration of5.0 mg/cm2provided100% protection up to60 and 90 min againstAe. aegypti andCx. quinquefasciatusrespectively.Conclusions: From the results it can be concluded the tetradecanoic acid is a potential for controlling Cx. quinquefasciatus andAe. aegypti mosquitoes.

  10. Mosquito larvicidal properties of Impatiens balsamina (Balsaminaceae) against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Marimuthu Govindarajan; Mohan Rajeswary

    2014-01-01

    Objective: To assess the larvicidal potential of the crude benzene, chloroform, ethyl acetate and methanol solvent extracts of the medicinal plant Impatiens balsamina against Anopheles stephensi(An. stephensi), Aedes aegypti (Ae. aegypti) and Culex quinquefasciatus (Cx. quinquefasciatus). Methods: Twenty five third instar larvae of An. stephensi, Ae. aegypti and Cx. quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using the protocol recommended by WHO. The larval mortality was observed after 24 h of treatment. Results: Among extracts tested, the highest larvicidal activity was observed in leaf methanol extract of Impatiens balsamina against An. stephensi, Ae. aegypti and Cx. quinquefasciatus with the LC50 and LC90 values 98.04, 119.68, 125.06 and 172.93, 210.14, 220.60 mg/L, respectively. Conclusions:From the results it can be concluded that the larvicidal effect of Impatiens balsamina against An. stephensi, Ae. aegypti and Cx. quinquefasciatus make this plant product promising as an alternative to synthetic insecticide in mosquito control programs.

  11. Measurement of the susceptibility of Culex pipiens pallens and Musca domestica to common insecticides in urban Henan province%河南省两市区蚊蝇对常用杀虫剂敏感性测定

    Institute of Scientific and Technical Information of China (English)

    刘吉起; 张玉勤; 唐振强; 郭祥树; 赵旭东

    2011-01-01

    Objective To determine the susceptibility of Culex pipiens pollens and Musca domestica to common insecticides in Henan province. Methods The dipping method and the topical application method were used to measure the susceptibility of Cx. Pipiens pollens and M. Domestica to commonly used insecticides. Results In Zhumadian city, the resistance ratio of Cx. Pipiens pollens to common insecticides was 1.36-67.37, and Cx. Pipiens pollens had the highest resistance to deltamethrin. The resistance ratio of M. Domestica was 6.36 to greater than 443.39, and M. Domestica had the highest resistance to propoxur. In Nanyang city, the resistance ratio of Cx. Pipiens pollens was 1.33-40.26, and Cx. Pipiens pollens had the highest resistance to beta-cypermethrin. The resistance ratio of M. Domestica was 6.34 to greater than 443.39, and M. Domestica had the highest resistance to propoxur. Conclusion Cx. Pipiens pollens populations in investigated cities were still sensitive to temephos and fenobucarb but resistant to deltamethrin and beta-cypermethrin. M. Domastica had developed different resistances to all insecticides. It is important to use insecticides appropriately to prevent the development of resistance in mosquitoes and houseflies.%目的 了解河南省淡色库蚊和家蝇对常用卫生杀虫剂的敏感性.方法 淡色库蚊采用幼虫浸渍法,家蝇采用点滴法进行测定.结果 驻马店市城区淡色库蚊对供试杀虫剂相对抗性倍数为1.36~67.37倍,其中溴氰菊酯的抗性倍数最高;家蝇对供试杀虫剂相对抗性倍数为6.36~>443.39倍,其中残杀威的抗性倍数最高.南阳市城区淡色库蚊对供试杀虫剂相对抗性倍数为1.33~40.26倍,其中高效氯氰菊酯的抗性倍数最高;家蝇对供试杀虫剂相对抗性倍数为6.34~>443.39倍,其中残杀威的抗性倍数最高.结论驻马店和南阳市城区的淡色库蚊对双硫磷和仲丁威保持相对敏感,对溴氰菊酯和高效氯氰菊酯产生

  12. 天津市2010年蚊蝇抗药性监测%Surveillance of the resistance of Culex pipiens pallens and Musca domestica to insecticides in Tianjin in 2010

    Institute of Scientific and Technical Information of China (English)

    吴彤宇; 张咏梅; 张静; 秦娜; 王伟; 李培羽; 李今越; 郝连义

    2012-01-01

    目的 了解天津市蚊、蝇对常用杀虫剂的抗药性,为科学合理使用杀虫剂提供依据.方法 选择6个区(县)作为监测点,分别用浸渍法和点滴法测定淡色库蚊和家蝇的抗药性.结果 天津市蚊、蝇对常用杀虫剂均产生了一定的抗性,淡色库蚊对DDVP、溴氰菊酯、高效氯氰菊酯、双硫磷和仲丁威的平均相对抗性分别为61.49、13.08、3.72、5.03和17.84倍;家蝇对DDVP、高效氯氰菊酯、溴氰菊酯、残杀威、氯菊酯的平均抗性分别为9.49、58.44、11.24、2.66和2.95倍.结论 各地应根据抗药性监测结果,合理应用杀虫剂,积极提倡综合防制,有效开展灭蚊、蝇工作.%Objective To study the resistance of Culex pipiens pollens and Musca domestica to insecticides in Tianjin in order to provide the basis for better use of insecticides. Methods Six districts(counties) of Tianjin were selected as the surveillance sites. The resistance of mosquitoes to insecticides was evaluated by dipping method, with the topical application method used for the detection of the resistance of houseflies. Results It was found that Cx. Pipiens pattens and M. Domestica in Tianjin were resistant to insecticides to a certain extent. The mean relative resistance of Cx. Pipiens pallens to DDVP, deltaMethri, (3 -Cypermethrin, parathion and fenobucarb were 61.49, 13.08, 3.72, 5.03 and 17.84, respectively, and that of M. Domestica to DDVP, (3-Cypermethrin, deltamethri, propoxur and permethin were 9.49, 58.44, 11.24, 2.66 and 2.95, respectively. Conclusion The resistance of Cx. Pipiens pallens and M. Domestica to different insecticides varies and the surveillance results should be a guidance for the reasonable use of the insecticides for better control of the insects.

  13. Ovicidal, larvicidal and adulticidal properties of Asparagus racemosus (Willd.) (Family: Asparagaceae) root extracts against filariasis (Culex quinquefasciatus), dengue (Aedes aegypti) and malaria (Anopheles stephensi) vector mosquitoes (Diptera: Culicidae).

    Science.gov (United States)

    Govindarajan, Marimuthu; Sivakumar, Rajamohan

    2014-04-01

    Several diseases are associated to the mosquito-human interaction. Mosquitoes are the carriers of severe and well-known illnesses such as malaria, arboviral encephalitis, dengue fever, chikungunya fever, West Nile virus and yellow fever. These diseases produce significant morbidity and mortality in humans and livestock around the world. The present investigation was undertaken to study the ovicidal, larvicidal and adulticidal activities of crude hexane, ethyl acetate, benzene, chloroform and methanol extracts of root of Asparagus racemosus were assayed for their toxicity against three important vector mosquitoes, viz., Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi (Diptera: Culicidae). The mean percent hatchability of the eggs was observed after 48 h post-treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. All the five solvent extracts showed moderate ovicidal activity; however, the methanol extract showed the highest ovicidal activity. The methanol extract of Asparagus racemosus against Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi exerted 100% mortality (zero hatchability) at 375, 300 and 225 ppm, respectively. Control eggs showed 99-100% hatchability. The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in methanol extract of root of Asparagus racemosus against the larvae of Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi with the LC50 and LC90 values were 115.13, 97.71 and 90.97 ppm and 210.96, 179.92, and 168.82 ppm, respectively. The adult mortality was observed after 24 h recovery period. The plant crude extracts showed dose-dependent mortality. At higher concentrations, the adult showed restless movement for some times with abnormal wagging and then died. Among the extracts tested, the highest adulticidal activity was observed in

  14. Evaluation of Pioneer eco-backpack sprayer and Twister XL backpack sprayer using Aqualuer against caged adult Aedes albopictus and Culex quinquefasciatus.

    Science.gov (United States)

    Xue, Rui-De; Qualls, Whitney A; Smith, Mike L; Zhao, Tong-Yan; Brown, James R

    2012-12-01

    A Pioneer Eco-Backpack electric cold ultra-low volume (ULV) sprayer and a gas-powered Twister XL 3950 series 2 motorized knapsack ULV sprayer with Aqualuer (20.6% permethrin AI) were evaluated against caged adult Aedes albopictus and Culex quinquefasciatus in St. Augustine, FL. The Pioneer Eco-Backpack sprayer provided 100% knockdown of both species of mosquitoes at 15 min; the Twister XL backpack sprayer resulted in 17-23% knockdown at 15 min. Both backpack sprayers with Aqualuer resulted in 100% mortality of both species at 24 h. The new Pioneer Eco-Backpack sprayer powered by electricity could be a potential tool for mosquito control.

  15. Detection of Culex flavivirus and Aedes flavivirus nucleotide sequences in mosquitoes from parks in the city of São Paulo, Brazil.

    Science.gov (United States)

    Fernandes, Licia Natal; de Paula, Marcia Bicudo; Araújo, Alessandra Bergamo; Gonçalves, Elisabeth Fernandes Bertoletti; Romano, Camila Malta; Natal, Delsio; Malafronte, Rosely dos Santos; Marrelli, Mauro Toledo; Levi, José Eduardo

    2016-05-01

    The dengue viruses are widespread in Brazil and are a major public health concern. Other flaviviruses also cause diseases in humans, although on a smaller scale. The city of São Paulo is in a highly urbanized area with few green spaces apart from its parks, which are used for recreation and where potential vertebrate hosts and mosquito vectors of pathogenic Flavivirus species can be found. Although this scenario can contribute to the transmission of Flavivirus to humans, little is known about the circulation of members of this genus in these areas. In light of this, the present study sought to identify Flavivirus infection in mosquitoes (Diptera: Culicidae) collected in parks in the city of São Paulo. Seven parks in different sectors of the city were selected. Monthly mosquito collections were carried out in each park from March 2011 to February 2012 using aspiration and traps (Shannon and CD C-CO2). Nucleic acids were extracted from the mosquitoes collected and used for reverse-transcriptase and real-time polymerase chain reactions with genus-specific primers targeting a 200-nucleotide region in the Flavivirus NS5 gene. Positive samples were sequenced, and phylogenetic analyses were performed. Culex and Aedes were the most frequent genera of Culicidae collected. Culex flavivirus (CxFV)-related and Aedes flavivirus (AEFV)- related nucleotide sequences were detected in 17 pools of Culex and two pools of Aedes mosquitoes, respectively, among the 818 pools of non-engorged females analyzed. To the best of our knowledge, this is the first report of CxFV and AEFV in the city of São Paulo and Latin America, respectively. Both viruses are insect- specific flaviviruses, a group known to replicate only in mosquito cells and induce a cytopathic effect in some situations. Hence, our data suggests that CxFV and AEFV are present in Culex and Aedes mosquitoes, respectively, in parks in the city of São Paulo. Even though Flavivirus species of medical importance were not

  16. Influence of some plant extracts on the ovi-position behavior of Aedes fluviatilis and Culex quinquifasciatus

    Directory of Open Access Journals (Sweden)

    Abdulhakim A. El Maghrbi

    2014-06-01

    Full Text Available Alcoholic/acetone extracts of nine species of plants (Allium tuberosum, Apium leptophylum, Carica papaya, Cymbopogon citratus, Euphorbia cotinofolia, Melia azedarach, Ocimum canum, Ricinus communis and Tagetes erecta were tested in respect to their influence on the ovi-position behavior of the mosquito, Aedes fluviatilis and Culex quinquifasciatus in concentrations of 100, 10 and 1 mg/L. Three days after mosquito females had fed on blood of anesthetized mice and pigeon respectively, experimental and control dishes were placed into cages for 24 h then number of eggs laid in each dish was counted. Alcoholic/acetone extracts of C. papaya, C. citratus and T. erecta at 100 mg/L; E. cotinofolia and O. canum at 100 and 10 mg/L were proved to be repulsive for ovi-position of Ae. fluviatilis. On the other hand, acetone extracts of A. tuberosum and M. azederach at 100 and 10 mg/L; A. leptophyllum, O. canum, E. cotinofolia and R. communis at 100 mg/L produced same effect on ovi-position behavior of Ae. fluviatilis. Alcoholic extracts E. cotinofolia, R. communis (100 mg/L and M. azedarach (100 and 10 mg/L were attractive to Cx. quinquifasciatus. Five acetone extracts (A. tuberosum, A. leptophylum, C. papaya, C. Citrates and M. azedarach were repulsive for ovi-position at 100 mg/L. Acetone extract of A. tuberosum and M. azedarach at 10 and 1 mg/L and C. citratus at 10 mg/L maintained the same properties. Our results concluded that each plant extract has the potential to control ovi-position behavior of mosquito. The differences in obtained responses necessitate the adoption of deeper research to isolate the active principle of such plants for potential use in mosquito control program.

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

    Science.gov (United States)

    Jayaraman, M; Senthilkumar, A; Venkatesalu, V

    2015-04-01

    In the present investigation, larvicidal potential of hexane, choloroform, ethyl acetate, acetone, and methanol extracts of seven aromatic plants, viz., Blumea mollis, Chloroxylon swietenia, Clausena anisata, Feronia limnonia, Lantana camera, Plectranthus amboinicus, and Tagetes erecta were screened against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. The larval mortality was observed after 12 and 24 h of exposure period. The results revealed that all the extracts showed varied levels of larvicidal activity against the mosquito species tested. However, the ethyl acetate extract of Chloroxylon swietenia showed the remarkable larvicidal activity against C. quinquefasciatus, Ae. aegypti, and An. stephensi. After 12 h of exposure period, the larvicidal activity was LC50 = 194.22 and LC90 = 458.83 ppm (C. quinquefasciatus), LC50 = 173.04 and LC90 = 442.73 ppm (Ae. aegypti), and LC50 = 167.28 and LC90 = 433.07 ppm (An. stephensi), and the larvicidal activity after 24-h exposure period was LC50 = 94.12 and LC90 = 249.83 ppm (C. quinquefasciatus), LC50 = 80.58 and LC90 = 200.96 ppm (Ae. aegypti), and LC50 = 76.24 and LC90 = 194.51 ppm (An. stephensi). The larvicidal potential of other plant extracts were in order of ethyl acetate extract of Clausena anisata > methanol extract of P. amboinicus > acetone extract of F. limonia > methanol extract of T. erecta > methanol extract of B. mollis > and methanol extract of L. camera. The results of the present study offer a possible way for further investigations to find out the active molecule responsible for the activity.

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

    Science.gov (United States)

    Chitra, Govindaraj; Balasubramani, Govindasamy; Ramkumar, Rajendiran; Sowmiya, Rajamani; Perumal, Pachiappan

    2015-04-01

    Mosquitoes and mosquito-borne diseases are prone to raise health and economic impacts. Synthetic insecticide-based interventions are indeed in situations of epidemic outbreak and sudden increases of adult mosquitoes. Nanoparticles are being used in many commercial applications and were found that aqueous silver ions can be reduced by an aqueous extract of plant parts to generate extremely stable silver nanoparticles in water. Based on this, silver nanoparticles (SNPs) were synthesized using leaf aqueous extract (LAE) of Mukia maderaspatana. Further, the synthesized SNPs were characterized by UV-visible spectrum, which indicated a strong plasmon resonance at 427 nm. X-ray diffraction (XRD) analysis revealed the average crystalline size of the synthesized SNPs was approximately 64 nm by Debye-Scherrer formulae. Fourier transform infrared (FTIR) spectroscopy analysis revealed the presence of different functional groups like amines, halides, alkanes, alkynes, amides, and esters with respective stretches, which are responsible for the bio-reduction of silver ions. Field emission scanning electron microscopy (FESEM) depicted the spherical morphology of SNPs with size range of 13-34 nm. The larvicidal activity of LAE and SNPs exhibited an effective mortality to Aedes aegypti and Culex quinquefasciatus. The lethal concentration (LC50; LC90) of LAE and SNPs were found to be 0.506; 1.082, 0.392; 0.870 ppm and 0.211; 0.703, 0.094; 0.482 ppm, respectively on A. aegypti and C. quinquefasciatus. Thus, the synthesized SNPs have shown preponderant larvicidal activity, but further studies are needed to formulate the potential larvicidal agents.

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

    Science.gov (United States)

    Senthilkumar, A; Jayaraman, M; Venkatesalu, V

    2013-03-01

    In the present investigation, the leaf essential oil of Feronia limonia was evaluated for chemical constituents and mosquito larvicidal activity against the larvae of Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. GC and GC-MS analyses revealed that the essential oil contain 51 compounds. Estragole (34.69 %) and β-pinene(23.59 %) were identified as the major constituents followed by methyl (Z)-caryophyllene (11.05 %), eugenol (6.50 %), linalool (3.97 %), phytol (3.27 %), sabinene (2.41 %) and limonene (2.27 %). Larval mortality was observed after 12 and 24 h of exposure period. The oil showed remarkable larvicidal activity against A. stephensi (LC(50) = 38.93 and LC(90) = 108.64 ppm (after 12 h); LC(50) = 15.03 and LC(90) = 36.69 ppm (after 24 h)), A. aegypti (LC(50) = 37.60 and LC(90) = 104.69 ppm (after 12 h); LC(50) = 11.59 and LC(90) = 42.95 ppm (after 24 h)) and C. quinquefasciatus (LC(50) = 52.08 and LC(90) = 124.33 ppm (after 12 h); LC(50) = 22.49 and LC(90) = 60.90 ppm (after 24 h)). Based on the results, the essential oil of F. limonia can be considered as a new source of larvicide for the control of vector mosquitoes.

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

    Science.gov (United States)

    Puglise, Jason M; Estep, Alden S; Becnel, James J

    2016-03-01

    Effective mosquito control is vital to curtail the devastating health effects of many vectored diseases. RNA interference (RNAi)-mediated control of mosquitoes is an attractive alternative to conventional chemical pesticides. Previous studies have suggested that transcripts for inhibitors of apoptosis (IAPs) may be good RNAi targets. To revisit and extend previous reports, we examined the expression of Aedes aegypti (L.) IAPs (AaeIAPs) 1, 2, 5, 6, 9, and a viral IAP-associated factor (vIAF) as well as Anopheles quadrimaculatus Say and Culex quinquefasciatus Say IAP1 homologs (AquIAP1 and CquIAP1) in adult females. Expression profiles of IAPs suggested that some older female mosquitoes had significantly higher IAP mRNA levels when compared to the youngest ones. Minor differences in expression of AaeIAPs were observed in mosquitoes that imbibed a bloodmeal, but the majority of the time points (up to 48 h) were not significantly different. Although in vitro experiments with the Ae. aegypti Aag-2 cell line demonstrated that the various AaeIAPs could be effectively knocked down within one day after dsRNA treatment, only Aag-2 cells treated with dsIAP1 displayed apoptotic morphology. Gene silencing and mortality were also evaluated after topical application and microinjection of the same dsRNAs into female Ae. aegypti. In contrast to previous reports, topical administration of dsRNA against AaeIAP1 did not yield a significant reduction in gene expression or increased mortality. Knockdown of IAP1 and other IAPs by microinjection did not result in significant mortality. In toto, our findings suggest that IAPs may not be suitable RNAi targets for controlling adult mosquito populations.

  1. Comparative mosquito repellency of essential oils against Aedes aegypti (Linn.), Anopheles dirus (Peyton and Harrison) and Culex quinquefasciatus (Say)

    Institute of Scientific and Technical Information of China (English)

    Siriporn Phasomkusolsil; Mayura Soonwera

    2011-01-01

    Objective: To assess the repellency to female Aedes aegypti (Ae. aegypti), Anopheles dirus (An. dirus) and Culex quinquefasciatus (Cx. quinquefasciatus) of seven essential oils using two treatment methods. Methods: Topical applications of three dose concentrations (0.02, 0.10 and 0.21 mg/cm2) were made on the forearms of volunteers. Dose-response study and protection time study were employed in the experiment. Results: In the dose-response test, Cymbopogon citratus (C. citratus), Cymbopogon nardus (C. nardus), Syzygium aromaticum (S. aromaticum) and Ocimum basilicum (O. basilicum) exhibited a high repellency against Ae. aegypti with ED50 at < 0.045 mg/cm2, whereas C. citratus, C. nardus and S. aromaticum showed repellency against An. dirus with ED50 at <0.068 mg/cm2. Furthermore, the essential oils of C. citratus, C. nardus, S. aromaticum, O.basilicum and Cananga odorata gave strong effective dose (ED 50) values at <0.003 mg/cm2 when tested against Cx. quinquefasciatus. For testing by arm in cage method, at 0.21 mg/cm2, protection time of C. citratus gave the longest lasting period against three mosquito species, 72 min for Ae. aegypti, 132 min for An. dirus and 84 min for Cx. quinquefasciatus. In addition, the two essential oils exhibited moderate repellency against Ae. aegypti, An. dirus and Cx. quinquefasciatus, at 60, 90 and 78 min with C. nardus, and 54, 96 and 72 min with S. aromaticum, respectively. Conclusions: The percentage repellency increased when the concentration of essential oils increased. In contrast, biting rates decreased when the concentration of essential oils increased.C. citratus exhibited high efficiency for the protection time and the percentage of biting deterrent against all of 3 mosquito species.

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

    Institute of Scientific and Technical Information of China (English)

    Govindarajan; M; Mathivanan; T; Elumalai; K; Krishnappa; K; Anandan; A

    2011-01-01

    Objective:To determine the ovicidal and repellent activities of methanol leaf extract of Ervatamia coronaria(E.coronaria) and Caeslpinia pulckerrima(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/cm under the laboratory conditions. Results:The crude extract of E.coronaria exerted zero hatchability(100%mortality) at 250.200 and 150 ppm for Cx.quinqitefasciatus,Ae.aegypti and An.stephensi,respectively.The crude extract of C.pulchenima 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.pukherrima extract.A higher concentration of 5.0 mg/cm~2 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.pukherrima are an excellent potential for controlling Cx.quinquefasciatus,Ae.aegypti and An.stephensi mosquitoes.

  3. 不同区域淡色库蚊对杀虫剂的抗性检验研究%An inspection of Culex pipiens pallens to Sixe Pesticides in different regions

    Institute of Scientific and Technical Information of China (English)

    罗进斌; 吴位新; 施红喜; 傅桂明; 任樟尧

    2011-01-01

    Objective :To investigate the level of the resistance of Culex pipiens pallens to six insecticides in City, suburbs, rural and mountainons, providing the basis for the study of mosquito resistance produced mechanism and scientific and reasonable use of pesticides. Methods: Immersion method of pesticide was used to assay the medium lethal concentration( LC5o ) of the Ⅳ larvae. Results:The Culex pipiens pallens were most resistant to permethrin which the resistance ratios were all above 10 times in each area, there were higher than medium resistance. The resistances to fenobucarb and tetramethrin were lower than other usual pesticides, the mosquitoes showed the lower resistance (RR <4). The resistance of rural was the highest to all sorts of insecticides in different regions. No statistical difference was found in the resistance between the natural populations from different regions ( F = 0. 583,P = 0. 678). Analysis of variance showed statistical difference in the varied insecticidal resistance of the natural populations to different agents ( F = 9.136, P = 0. 000). Conclusion: The Culex pipiens pallens demonstrated varied resistance to the 6 pesticides, and were most resistant to permethrin. On the contrary, there were no insecticide resistance against fenobucarb and tetramethrin. The monitoring of its insecticide resistance should be strengthened in conjunction with proper application of insecticides in order to delay resistance evolution.%目的:了解金华市城区、郊区、农村和山区四个不同区域淡色库蚊对6种常用杀虫剂的抗药性水平,为研究蚊虫抗性产生机制及科学合理使用杀虫剂提供依据.方法:采用药液浸渍法,测定4龄期幼虫半数致死浓度(LC).结果:金华市各区域淡色库蚊对氯菊酯抗性倍数最高,均大于10倍,属中抗以上水平;对仲丁威和胺菊酯的抗性倍数较低,均小于4倍,属低抗水平.四个区域中,农村淡色库蚊对各种杀虫剂的抗性最高,其中

  4. Mediterranean essential oils as effective weapons against the West Nile vector Culex pipiens and the Echinostoma intermediate host Physella acuta: what happens around? An acute toxicity survey on non-target mayflies.

    Science.gov (United States)

    Benelli, Giovanni; Bedini, Stefano; Flamini, Guido; Cosci, Francesca; Cioni, Pier Luigi; Amira, Smain; Benchikh, Fatima; Laouer, Hocine; Di Giuseppe, Graziano; Conti, Barbara

    2015-03-01

    Mosquitoes (Diptera: Culicidae) represent a threat for millions of people worldwide, since they act as vectors for important pathogens, including malaria, yellow fever, dengue and West Nile. Second to malaria as the world's most widespread parasitic disease, infection by trematodes is a devastating public health problem. In this study, we proposed two essential oils from plants cultivated in Mediterranean regions as effective chemicals against mosquitoes and freshwater snails vectors of Echinostoma trematodes. Chemical composition of essential oils from Achillea millefolium (Asteraceae) and Haplophyllum tuberculatum (Rutaceae) was investigated. Acute toxicity was evaluated against larvae of the West Nile vector Culex pipiens (Diptera: Culicidae) and the invasive freshwater snail Physella acuta (Mollusca: Physidae), an important intermediate host of many parasites, including Echinostoma revolutum (Echinostomidae). Acute toxicity of essential oils was assessed also on a non-target aquatic organism, the mayfly Cloeon dipterum (Ephemeroptera: Baetidae). Achillea millefolium and H. tuberculatum essentials oils were mainly composed by oxygenated monoterpenes (59.3 and 71.0 % of the whole oil, respectively). Chrysanthenone and borneol were the two major constituents of Achillea millefolium essential oil (24.1 and 14.2 %, respectively). Major compounds of H. tuberculatum essential oil were cis-p-menth-2-en-1-ol and trans-p-menth-2-en-1-ol (22.9 and 16.1 %, respectively). In acute toxicity assays, C. pipiens LC50 was 154.190 and 175.268 ppm for Achillea millefolium and H. tuberculatum, respectively. P. acuta LC50 was 112.911 and 73.695 ppm for Achillea millefolium and H. tuberculatum, respectively, while the same values were 198.116 and 280.265 ppm for C. dipterum. Relative median potency analysis showed that both tested essential oils were more toxic to P. acuta over C. dipterum. This research adds knowledge on plant-borne chemicals toxic against invertebrates of medical

  5. Efficacy of seed extracts of Annona squamosa and Annona muricata (Annonaceae) for the control of Aedes albopictus and Culex quinquefasciatus (Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Fara Nantenaina Raharimalala; Beby Rasoahantaveloniaina; Pierre Herv Ravelonandro; Patrick Mavingui

    2014-01-01

    Objective: To evaluate the potential efficacy of seed extracts of Annona squamosa and Annona muricata used as natural insecticides to control adult and larvae of the vectors Aedes albopictus and Culex quinquefasciatus under laboratory conditions. Methods:Aqueous and oil extracts of the two plants were prepared from dried seeds. Preliminary identifications of the chemical components of each seed extracts were performed using micro-reactional and GCP techniques. Larvae and adults of Aedes albopictus and Culex quinquefasciatus were collected from the breeding sites in coastal and highlands regions of Madagascar. WHO standardized tests of susceptibility for larvae and imaginal stage of mosquitoes were realized to determine mortality and LC50 of mosquitoes. Results: Chemical identifications showed that these extracts contain alkaloids and flavonoids compounds that probably confer their biological insecticidal proprieties. CPG analysis showed also the presence of various fatty acids. On adult mosquitoes, significant insecticidal effects were observed with both aqueous and oil extracts of the two plant seeds compared to mortality induced by deltamethrin, an insecticide used as reference. Extracts of Annona muricata induced high mortality rate to both species of mosquito compared to extracts of Annona squamosa at all concentrations tested. The LC50 of seed extracts ranged from 1% to 5% for adults and 0.5% to 1% for larvae. Conclusions: The seed extracts of these two plants may be used as mosquito controlling agents and offer a new approach to a less costly, practical and environmentally friendly control of vector borne diseases.

  6. Laboratory Transmission of Japanese Encephalitis and West Nile Viruses by Molestus Form of Culex pipiens (Diptera: Culicidae) Collected in Uzbekistan in 2004

    Science.gov (United States)

    2006-02-01

    variety of incubation periods, the dissemination rate increased after 14-d extrinsic incubation and was 80% for those Cx. pipi - ens held for 16Ð25 d at...1983. The effect of laboratory colonization on the vector pathogen interactions of Egyptian Culex pipi - ens and Rift Valley fever virus. Am. J. Trop.Med

  7. Study on the pathogenicity of five strains of entomopathogenic fungi to Culex pipiens pallens larvae%5株虫生真菌对淡色库蚊幼虫的致病力研究

    Institute of Scientific and Technical Information of China (English)

    刘丽娟; 韦玮; 张本光; 代玉华; 王海防; 程鹏; 王怀位; 公茂庆

    2011-01-01

    Objective To test the pathogenicity of 5 strains of entomopathogenic fungi to Culex pipiens pallens larvae and select the highly pathogenic strain against Cx. pipiens pallens, providing a scientific basis for the prevention and control of the insect. Methods The five fungal strains that are commonly used in biological control were used for the detection of the cumulative motality rates of Cx. pipiens pallens larvae caused by different concentrations of fungal spore suspension, with the median lethal concentration (LC50) values worked out. Results Evaluated based on the growth rate and sporulation, all of the five strains showed different degrees of pathogenicity against Cx. pipiens pallens larvae. At 10 days, the five strains GIM3.428,GIM3.45,GIM3.431, GIM3.95 and GIM3.436 resulted in a cumulative mortality rate of 100%, 82%, 79%, 73% and 57%, with the LC50 being 2.98 × 102、 1.41 × 103、 1.26 × 104、 1.02 × 104、 2.07 × 105 conidia/ml, respectively. Conclusion The fungal strain GIM3.428, which is of the highest pathogenicity against Cx. pipiens pallens larvae, can be used for the control of the insect.%目的 测定菌株对淡色库蚊幼虫的致病力,筛选出高致病力菌株,为淡色库蚊的防治提供理论依据.方法 选择生物防治中常用的5株菌株,测定不同浓度的孢子悬浮液对淡色库蚊幼虫的累计死亡率,计算半数致死浓度(LC50).结果 菌株GIM3.428、GIM3.45、GIM3.431、GIM3.95以及GIM3.436对淡色库蚊幼虫均具有致病性,试验10d,淡色库蚊幼虫累计死亡率分别为100%、82%、79%、73%和57%,菌株对淡色库蚊幼虫的LC50分别为2.98×102、1.41×103、1.26×104、1.02×104、2.07×105孢子/ml.结论 菌株GIM3.428对淡色库蚊幼虫的致病力最高,可将其应用于淡色库蚊的防治.

  8. Adulticidal and repellent properties of Cassia tora Linn. (Family: Caesalpinaceae) against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi.

    Science.gov (United States)

    Amerasan, Duraisamy; Murugan, Kadarkarai; Kovendan, Kalimuthu; Mahesh Kumar, Palanisamy; Panneerselvam, Chellasamy; Subramaniam, Jayapal; John William, Samuel; Hwang, Jiang-Shiou

    2012-11-01

    Mosquitoes have developed resistance to various synthetic insecticides, making its control increasingly difficult. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. The adulticidal and repellent activities of crude hexane, chloroform, benzene, acetone, and methanol extracts of the leaf of Cassia tora were assayed for their toxicity against three important vector mosquitoes, viz., Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. The adult mortality was observed after 24 h of exposure. All extracts showed moderate adulticidal effects; however, the highest adult mortality observed was found in methanol extract. The LC(50) and LC(90) values of C. tora leaf extracts against adulticidal activity of (hexane, chloroform benzene, acetone, and methanol) C. quinquefasciatus, A. aegypti, and A. stephensi were the following: C. quinquefasciatus LC(50) values were 338.81, 315.73, 296.13, 279.23, and 261.03 ppm and LC(90) values were 575.77, 539.31, 513.99, 497.06, and 476.03 ppm; A. aegypti LC(50) values were 329.82, 307.31, 287.15, 269.57, and 252.03 ppm and LC(90) values were 563.24, 528.33, 496.92, 477.61, and 448.05 ppm; and A. stephensi LC(50) values were 317.28, 300.30, 277.51, 263.35, and 251.43 ppm and LC(90) values were 538.22, 512.90, 483.78, 461.08, and 430.70 ppm, respectively. The results of the repellent activity of hexane, chloroform, benzene, acetone, and methanol extracts of C. tora plant 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, this 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 eco-friendly approach for the control of

  9. 41种植物精油对淡色库蚊的熏蒸活性%Fumigation activity of 41 essential oils against Culex pipiens pallens (Diptera: Culicidae)

    Institute of Scientific and Technical Information of China (English)

    付臣臣; 万涛; 江志利; 吴华; 冯俊涛; 马志卿; 张兴

    2013-01-01

    为发现具有较高杀蚊活性的精油,推动植物精油类卫生杀虫剂的创制,本研究采用三角瓶熏蒸法测定了17科41种植物精油对淡色库蚊Culex pipiens pallens雌成蚊的熏蒸活性,并进一步采用密闭圆筒法验证其杀虫毒力大小.三角瓶熏蒸法测定表明,在12μL/L浓度下,留兰香油(spearmint oil)、薰衣草油(lavender oil)、山苍子油(Litsea cubeba oil)等26种精油均有较强的熏蒸作用,KT50小于15 min.该26种精油用密闭圆筒熏蒸法进一步测定表明,在浓度为10 μL/L时,冬青油(wintergreen oil)、艾叶油(blumea oil)、薄荷油(peppermint oil)、桉叶油(Eucalyptus robusta oil)和蓝桉油(E.globulus oil)等植物精油熏蒸活性较强,其KT50分别为16.91,21.20,22.57,18.43和19.48 min.结果证明冬青油、艾叶油、薄荷油、桉叶油和蓝桉油等5种精油对淡色库蚊具有较强的熏蒸活性,具备作为淡色库蚊防控剂开发的潜力,值得进一步研究.%To find the essential oils with high insecticidal activity and promote the development of hygienic insecticides,essential oils from 41 plants belonging to 17 families were evaluated for adulticidal activity against female adults of Culex pipiens pallens by airtight fumigation in conical flask and hermetic round canister method.The results showed that 26 essential oils (12 μL/L) including spearmint oil,lavender oil and Litsea cubeba oil were very toxic to the mosquito (KT50 < 15 min) by airtight fumigation in conical flask.Further assay using hermetic round canister method indicated that 5 essential oils (wintergreen oil,blumea oil,peppermint oil,Eucalyptus robusta oil and E.globulus oil) had high fumigation toxicity at the concentration of 10 μL/L,and their KT50 values were 16.91,21.20,22.57,18.43 and 19.48 min,respectively.The results demonstrate that wintergreen oil,blumea oil,peppermint oil,E.robusta oil and E.globulus oil all have high fumigation activity against C.pipiens pallens,with the

  10. Characterization of the doublesex gene within the Culex pipiens complex suggests regulatory plasticity at the base of the mosquito sex determination cascade

    OpenAIRE

    Price, Dana C.; Egizi, Andrea; Dina M Fonseca

    2015-01-01

    Background The doublesex gene controls somatic sexual differentiation of many metazoan species, including the malaria mosquito Anopheles gambiae and the dengue and yellow fever vector Aedes aegypti (Diptera: Culicidae). As in other studied dipteran dsx homologs, the gene maintains functionality via evolutionarily conserved protein domains and sex-specific alternative splicing. The upstream factors that regulate splicing of dsx and the manner in which they do so however remain variable even am...

  11. Chemical composition and larvicidal activity of essential oil from Ocimum basilicum (L.) against Culex tritaeniorhynchus, Aedes albopictus and Anopheles subpictus (Diptera: Culicidae).

    Science.gov (United States)

    Govindarajan, M; Sivakumar, R; Rajeswary, M; Yogalakshmi, K

    2013-05-01

    The toxicity of mosquito larvicidal activity of leaf essential oil and their major chemical constituents from Ocimum basilicum were evaluated against Culex tritaeniorhynchus, Aedes albopictus and Anopheles subpictus. The chemical composition of the leaf essential oil was analyzed using gas chromatography-mass spectroscopy. GC-MS revealed that the essential oil of O. basilicum contained 20 compounds. The major chemical components identified were linalool (52.42%), methyl eugenol (18.74%) and 1, 8-cineol (5.61%). The essential oil had a significant toxic effect against late third-stage larvae of Cx. tritaeniorhynchus, Ae. albopictus and An. subpictus with an LC(50) values of 14.01, 11.97 and 9.75 ppm and an LC(90) values of 23.44, 21.17 and 18.56 ppm, respectively. The results could be useful in search for newer, safer, and more effective natural larvicidal agents against Cx. tritaeniorhynchus, Ae. albopictus and An. subpictus.

  12. Ipomoea batatas (Convolvulaceae)-mediated synthesis of silver nanoparticles for controlling mosquito vectors of Aedes albopictus, Anopheles stephensi, and Culex quinquefasciatus (Diptera:Culicidae).

    Science.gov (United States)

    Pavithra Bharathi, V; Ragavendran, C; Murugan, N; Natarajan, D

    2016-12-08

    We proposed an effective and eco-friendly control of dengue, malaria, and filariasis-causing vectors. We tested Ipomoea batatas leaves-mediated silver nanoparticles (AgNPs) against first to fourth instar larvae and adults of Aedes albopictus, Anopheles stephensi, and Culex quinquefasciatus at different concentrations. The synthesized AgNPs showed broad spectrum of larvicidal and adulticidal effects after 48 h of exposure. The characterization of synthesized AgNPs was done using various spectral and microscopy analyses. The maximum efficacy was observed in synthesized AgNPs against the adult of Ae. albopictus with the LC50 and LC90 values were 10.069 and 15.657 μg/mL, respectively, followed by others.

  13. Efficacy of seed extracts of Annona squamosa and Annona muricata(Annonaceae) for the control of Aedes albopictus and Culex quinquefasciatus(Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Lala; Harivelo; Raveloson; Ravaomanarivo; Herisolo; Andrianiaina; Razafindraleva; Fara; Nantenaina; Raharimalala; Beby; Rasoahantaveloniaina; Pierre; Herv; Ravelonandro; Patrick; Mavingui

    2014-01-01

    Objective:To evaluate the potential efficacy of seed extracts of Annona squamosa and Annona muricata used as natural insecticides to control adult and larvae of the vectors Aedes albopictus and Culex quinquefasciatus under laboratory conditions.Methods:Aqueous and oil extracts of the two plants were prepared from dried seeds.Preliminary identifications of the chemical components of each seed extracts were performed using microreactional and GCP techniques.Larvae and adults of Aedes albopictus and Culex quinquefasciatus were collected from the breeding sites in coastal and highlands regions of Madagascar.WHO standardized tests of susceptibility for larvae and imaginal stage of mosquitoes were realized to determine mortality and LC50 of mosquitoes.Results:Chemical identifications showed that these extracts contain alkaloids and flavonoids compounds that probably confer their biological insecticidal proprieties.CPG analysis showed also the presence of various fatty acids.On adult mosquitoes,significant insecticidal effects were observed with both aqueous and oil extracts of the two plant seeds compared to mortality induced by deltamethrin,an insecticide used as reference.Extracts of Annona muricata induced high mortality rate to both species of mosquito compared to extracts of Annona squamosa at all concentrations tested.The LC50 of seed extracts ranged from 1%to 5%for adults and 0.5%to 1%for larvae.Conclusions:The seed extracts of these two plants may be used as mosquito controlling agents and offer a new approach to a less costly,practical and environmentally friendly control of vector borne diseases.

  14. Trap effects of different physical and chemical attractants on Culex pipiens quinquefasciatus%不同物理、化学因子对致倦库蚊的引诱效果研究

    Institute of Scientific and Technical Information of China (English)

    谷依露; 高小峰; 杨晓菁; 葛台明

    2012-01-01

    Objective To observe the trap effects of several different physical and chemical attractants on adult Culex pipiens quinquefasciatus, providing better designs of new mosquito trap devices. Methods The "Y" - tube olfactometer was used to measure the trap effects of seven chemicals (urea, lactic acid, glycerol, dodecanoic acid, tetradecanoic acid, hexadecanoic acid and nonyl aldehyde) and two physical attractants (sound and visible light) on adult Cx. Pipiens quinquefasciatus. The number of individuals attracted by the tested attractants was calculated and compared among the groups. Results Chemical attractants including urea (10 mg/L), lactic acid (1000 mg/L), hexadecanoic acid (10 mg/L), nonyl aldehyde (0.1 mg/L) and physical attractants including 150 Hz sinus tone and 380 nm visible light had better mosquito trap effects. Conclusion The chemical and physical attractants mentioned above can be introduced to the design of mosquito trap devices to improve the efficiency of mosquito control.%目的 研究不同物理、化学因子对致倦库蚊的引诱效果,以更好地设计改进新一代灭蚊器.方法 使用Y形嗅觉测试仪测定化学因子(尿素、乳酸、丙三醇、十二烷酸、十四烷酸、十六烷酸、壬醛)以及物理因子(声波和可见光)对致倦库蚊成虫的引诱作用;将致倦库蚊成虫逐只放入Y形嗅觉测试仪,统计飞入处理端的个体数,通过比较得出对致倦库蚊具有较好引诱效果的物理、化学因子.结果 对致倦库蚊具有较高引诱率的化学因子有尿素(10 mg/L)、乳酸(1000 mg/L)、十六烷酸(10 mg/L)和壬醛(0.1 mg/L);物理因子中150 Hz的正弦波和380 nm的可见光分别对致倦库蚊具有较高引诱率.结论 可将上述引诱效果较佳的物理、化学因子引入到灭蚊器的设计生产中,以提高灭蚊效率.

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

    Science.gov (United States)

    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

  16. Experimental observation of toxic effect of Bacillus thuringiensis var. israelen-sis against Aedes,Culex and Anopheles larvae%苏云金杆菌以色列变种对伊蚊库蚊和按蚊幼虫毒效的实验观察

    Institute of Scientific and Technical Information of China (English)

    李菊林; 朱国鼎; 周华云; 唐建霞; 曹俊

    2014-01-01

    目的:研究苏云金杆菌以色列变种(Bti)可湿性粉剂对伊蚊、库蚊和按蚊幼虫的毒杀效果。方法采用生物测定法,测定Bti可湿性粉剂对白纹伊蚊幼虫、淡色库蚊幼虫和中华按蚊幼虫的毒杀效果,计算半数致死浓度(LC50)。结果 Bti可湿性粉剂对Ⅲ龄白纹伊蚊幼虫、淡色库蚊幼虫和中华按蚊幼虫的LC50分别为0.104、0.160μg/ml和0.324μg/ml,效价分别为0.125、0.192 IU/ml和0.389 IU/ml;连续接触中华按蚊Ⅲ龄幼虫1、2 d和3 d的LC50分别为0.324、0.092μg/ml和0.032μg/ml,效价分别为0.389、0.110 IU/ml和0.038 IU/ml;对中华按蚊Ⅰ、Ⅱ、Ⅲ龄和Ⅳ龄幼虫的LC50分别为0.024、0.137、0.324μg/ml和0.450μg/ml,效价分别为0.029、0.164、0.389 IU/ml和0.540 IU/ml。结论 Bti对3种蚊虫幼虫均有较好的毒杀效果,但对伊蚊和库蚊幼虫效果更好,且幼虫虫龄越小,毒杀效果越好。%Objective To evaluate the toxic effect of Bacillus thuringiensis var. israelensis(Bti)wettable powder against Ae-des,Culex and Anopheles larvae. Methods The biological assay was applied to test the lethal concentration of 50%(LC50)of Bti wettable powder against Aedes,Culex and Anopheles larvae. Results The LC50(s) of Bti wettable powder against Aedes albopictus, Culex pipiens pallens and Anopheles sinensis larvae were 0.104,0.160μg/ml and 0.324μg/ml,respectively;its biological poten-cies against them were 0.125,0.192 IU/ml and 0.389 IU/ml,respectively. The LC50(s) of continuous contact of Bti wettable powder with An. sinensis stageⅢlarvae for 1,2 d and 3 d were 0.324,0.092μg/ml and 0.032μg/ml,respectively,and its biological po-tencies were 0.389,0.110 IU/ml and 0.038 IU/ml,respectively. The LC50(s) of the bacteria against An. sinensis stageⅠ,Ⅱ,Ⅲ,Ⅳwere 0.024,0.137,0.324 μg/ml and 0.450 μg/ml,respectively,and the biological potencies were 0.029,0.164,0.389 IU/ml and 0.540 IU/ml,respectively. Conclusion Bti wettable

  17. Chemical composition and larvicidal activity of essential oil of Origanum majorana(Lamiaceae) cultivated in Morocco against Culex pipiens(Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

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

    2014-01-01

    Objective:To evaluate the larvicidal activity of essential oil of Origanum mtijoruna(Lamiaceae)cultivated in Morocco against Culex pipiens(Diptera:Culicidae).Methods:The analysis and the identification of the various constituents of essential oil were carried out by gas chromatography coupled with mass spectrometry.Biological test was performed according to a standard methodology inspired by the World Health Organization protocol with slight modification.Results:This oil mainly consisted of monoterpene and sesquiterpenes.The majority compounds are 4-terpinene(28.96%),y-terpinene(18.57%),α-terpinene(12.72%) and sabinene(8.02%).The lethal concentrations(LC50 and LC90) measured for the essential oil Origanum majorana,were respectively of the order of 258.71 mg/L and 580.49 mg/L.Conclusions:The results could be useful in search for newer,safer,and more effective natural larvicidal agents.

  18. 淡色库蚊对3种化学杀虫剂交互抗性的实验研究%Experimental study on cross-resistance of Culex pipiens pallens to 3 kinds of chemical pesticides

    Institute of Scientific and Technical Information of China (English)

    蒋滨; 李士根; 全芯; 薛庆节; 谭文彬; 刘永春; 王新国; 王怀位

    2014-01-01

    目的:了解淡色库蚊对常用化学杀虫剂的交互抗性,为合理使用化学杀虫剂提供依据。方法采用WHO生物测定方法,检测淡色库蚊敏感品系和抗敌敌畏、抗残杀威、抗氯氰菊酯3种抗性品系IV龄幼虫分别对敌敌畏、残杀威和氯氰菊酯3种化学杀虫剂的抗性。结果淡色库蚊抗敌敌畏品系对敌敌畏、残杀威和氯氰菊酯3种化学杀虫剂的抗性系数分别为14.47、8.96和207.27,抗残杀威品系对上述3种杀虫剂的抗性系数分别为3.27、6.93和8.65,抗氯氰菊酯品系对3种杀虫剂的抗性系数分别为2.93、1.61和501.11。结论长期使用一种化学杀虫剂易产生抗性,并对其他化学杀虫剂产生不同程度的交互抗性。使用杀虫剂时应注意选择药物品种和剂量,以避免和延缓蚊虫抗药性的产生。%Objective To understand the cross-resistance of Culex pipiens pallens to common pesticides,so as to provide the evidence for improving the application of chemical pesticides. Methods The IV instar larvae of DDVP-resistant,propoxur-resistant and cypermethrin-resistant strains as well as the sensitive strain of Culex pipiens pallens were collected to detect the re-sistance to DDVP,propoxur and cypermethrin based on the WHO bioassay method. Results The resistance coefficients of DDVP-resistant strain to DDVP,propoxur and cypermethrin were 14.47,8.96 and 207.27 respectively. The resistance coeffi-cients of propoxur-resistant strain to DDVP,propoxur and cypermethrin were 3.27,6.93 and 8.65 respectively. The resistance coefficients of cypermethrin-resistant strain to DDVP,propoxur and cypermethrin were 2.93,1.61 and 501.11 respectively. Con-clusion The resistance and cross-resistance could be generated during the long-term application of a single kind of chemical pesticide,and we should pay more attention to the varieties and dosages of them.

  19. Mapping of zones potentially occupied by Aedes vexans and Culex poicilipes mosquitoes, the main vectors of Rift Valley fever in Senegal

    Directory of Open Access Journals (Sweden)

    Yves M. Tourre

    2008-11-01

    Full Text Available A necessary condition for Rift Valley fever (RVF emergence is the presence of Aedes (Aedimorphus vexans and Culex (Culex poicilipes mosquitoes carrying the arbovirus and responsible for the infection. This paper presents a detailed mapping in the Sahelian region of Senegal of zones potentially occupied by these mosquitoes (ZPOMs whose population density is directly linked to ecozones in the vicinity of small ponds. The vectors habitats and breeding sites have been characterized through an integrated approach combining remote sensing technology, geographical information systems, geographical positioning systems and field observations for proper geo-referencing. From five SPOT-5 images (~10 m spatial resolution with appropriate channels, a meridional composite transect of 290 x 60 km was first constructed at the height of the summer monsoon. Subsequent ZPOMs covered major ecozones from north to south with different hydrological environments and different patterns pond distributions. It was found that an overall area of 12,817 ha ± 10% (about 0.8% of the transect is occupied by ponds with an average ZPOM 17 times larger than this (212,813 ha ± 10% or about 14% of the transect. By comparing the very humid year of 2003 with 2006 which had just below normal rainfall, the ZPOMs inter-annual variability was analyzed in a sandy-clayey ecozone with an important hydrofossil riverbed within the Ferlo region of Senegal. Very probably contributing to an increased abundance of vectors by the end of August 2003, it was shown that the aggregate pond area was already about 22 times larger than in August 2006, corresponding to an approximately five times larger total ZPOM. The results show the importance of pin-pointing small ponds (sizes down to 0.1 ha and their geographical distribution in order to assess animal exposure to the RVF vectors.

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

    Science.gov (United States)

    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

  1. 淡色库蚊幼虫对7种杀虫剂的敏感性和抗性调查%Survey on the sensitivity and resistance of Culex pipiens pallens larva to seven kinds of insecticide

    Institute of Scientific and Technical Information of China (English)

    陈志龙; 陈东亚; 刘慧; 杨维芳; 褚宏亮; 刘大鹏; 张爱军; 徐燕; 孙俊

    2011-01-01

    Objective To investigate the resistance of Culex pipiens pallens larva to insecticides in Jiangsu Province and provide scientific evidence for control. Methods Larva immersion method. Results The lab population was the most susceptive with LC50 of 0.001 3 mg/L to deltamethrin, 0.003 8 mg/L to beta -cypermethrin, 0.027 7 mg/L to permethrin, 0. 181 3 mg/L to esbiothrin,0. 018 3 mg/L to DDVP, 0.096 8 mg/L to propoxur and 0. 000 4 mg/L to temephos. The highest resistance ratio of insecticide was 200 in Nanjing, Xuzhou, Lianyungang and Wuxi. Conclusion In Jiangsu Province C. pipens pallens have developed different resistance to DDVP, temephos, deltamethrin, beta - cypermethrin and propoxur. It is necessary to use the result of survey to prevent the resistance from developing.%目的 为了解江苏省淡色库蚊幼虫对卫生杀虫剂的敏感性和抗药性发生发展状况进行生物学抗性调查.方法 幼虫浸渍法.结果 实验室淡色库蚊幼虫对溴氰菊酯、高效氯氰菊酯、氯菊酯、生物丙烯菊酯、敌敌畏、残杀威和双硫磷幼虫敏感性LC50分别为0.001 3、0.003 8、0.027 7,0.181 3、0.018 3、0.096 8、0.000 4 mg/L.南京、徐州、连云港和无锡等地蚊虫幼虫抗性分别是敏感品系的数倍到200倍不等.结论 江苏省淡色库蚊幼虫对敌敌畏、双硫磷、溴氰菊酯、高效氯氰菊酯和残杀威等杀虫剂均产生不同程度的抗性.抗性调查的结果为指导江苏省蚊虫防治以及合理使用卫生杀虫剂提供科学依据.

  2. In vitro Mosquito Larvicidal Activity of Marine Algae Against the Human Vectors, Culex quinquefasciatus (Say and Aedes aegypti (Linnaeus (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Akbar Idhayadhulla

    2011-01-01

    Full Text Available A total of twenty marine algae were collected from the rocky intertidal and subtidal regions of the southwest coast of India and extracted in methanol. The extracts were evaluated for larvicidal activity against the second and third instar larvae of the human vector mosquito Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae. Analysis on the activity profile of the above marine algae indicated that the early stage larvae were very sensitive to seven seaweed extracts that had been tested. Among the seven marine algae, Lobophora variegata was highly potential, showing LD50 value of 70.38 and 79.43 g mL-1 on the 2nd instar larvae of A. aegypti and C. quinquefasciatus respectively. The rank of larvicidal potency in highly active algae in the descending order is as follows: Lobophora variegata (Dictyotaceae>Spatoglossum asperum (Dictyotaceae>Stoechospermum marginatum (Dictyotaceae>Sargassum wightii (Sargassaceae >Acrosiphonia orientalis (Acrosiphoniaceae>Centroceras clavulatum (Ceramiacea>Padina tetrastromatica (Dictyotaceae. This is the first report that envisaged the mosquito larvicidal efficacy of L. variegata from the Indian coast. Therefore, this marine alga could be recognized as a potential resource of natural insecticide and can be developed to replace synthetic insecticides in future.

  3. Pathogenicity of the Fungus, Aspergillus clavatus, isolated from the locust, Oedaleus senegalensis, against larvae of the mosquitoes Aedes aegypti, Anopheles gambiae and Culex quinquefasciatus.

    Science.gov (United States)

    Seye, Fawrou; Faye, Oumar; Ndiaye, Mady; Njie, Ebrima; Marie Afoutou, José

    2009-01-01

    The use of insect pathogenic fungi is a promising alternative to chemical control against mosquitoes. Among the Hyphomycetes isolated from insects for mosquito control, the genus Aspergillus remains the least studied. In September 2005, four fungi were isolated from the Senegalese locust, Oedaleus senegalensis Kraus (Orthoptera: Acrididae), collected in Dakar, Senegal. One of these fungi, identified as Aspergillus clavatus, Desmazières (Eurotiales: Trichocomaceae) was highly pathogenic against larvae of the mosquitoes Aedes aegypti L., Anopheles gambiae s.l. Giles and Culex quinquefasciatus Say (Diptera: Culicidae). An application of 1.2 mg/ml dry conidia yielded 100% mortality after 24 hours against both Ae. aegypti and Cx. quinquefasciatus while with An. gambiae it was 95%. With unidentified species in the genus Aspergillus, mortality after 24 h was studies revealed that A. clavatus penetrated the cuticle, invaded the gut and disintegrated its cells. Some Cx. quinquefasciatus larvae, treated with A. clavatus reached the pupal stage and produced infected adults. However, the infection was mainly located on the extremity of their abdomen. These results suggest that A. clavatus could be an effective tool to manage mosquito proliferation.

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

    Science.gov (United States)

    Phasomkusolsil, Siriporn; Soonwera, Mayura

    2010-07-01

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

  5. 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).

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. Evaluation of Andrographis paniculata Burm.f. (Family:Acanthaceae) extracts against Culex quinquefasciatus (Say.) and Aedes aegypti (Linn.) (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Marimuthu Govindarajan

    2011-01-01

    Objective:To investigate the larvicidal and ovicidal efficacy of different extracts of Andrographis paniculata (A. paniculata) against Culex quinquefasciatus (Cx. quinquefasciatus) Say and Aedes aegypti (Ae. aegypti ) L. (Diptera:Culicidae). Methods:Larvicidal efficacy of the crude leaf extracts of A. paniculata with five different solvents like benzene, hexane, ethyl acetate, methanol and chloroform was tested against the early third instar larvae of Cx. quinquefasciatus and Ae. aegypti. The ovicidal activity was determined against two mosquito species to various concentrations ranging from 50-300 ppm under the laboratory conditions. Results:The benzene, hexane, ethyl acetate, methanol and chloroform leaf extract of A. paniculata was found to be more effective against Cx. quinquefasciatus than Ae. aegypti. The LC50 values were 112.19, 137.48, 118.67, 102.05, 91.20 ppm and 119.58, 146.34, 124.24, 110.12, 99.54 ppm respectively. Among five tested solvent, methanol and ethyl acetate crude extract was found to be most effective for ovicidal activity against two mosquito species. The extract of methanol and ethyl acetate exerted 100%mortality at 200 ppm against Cx. quinquefasciatus and at 250 ppm against Ae. aegypti. Conclusions:From the results it can be concluded the crude extract of A. paniculata was a potential for controlling Cx. quinquefasciatus and Ae. aegypti mosquitoes.

  8. Study on the biological characteristics of Culex pipiens pallens resistance to cypermethrin and susceptibility of the species at different temperatures%温度对抗氯氰菊酯和敏感品系淡色库蚊生物学特性的影响

    Institute of Scientific and Technical Information of China (English)

    刘贵献; 代玉华; 杨秋兰; 程鹏; 王海防; 刘丽娟; 赵玉强; 王怀位; 公茂庆

    2011-01-01

    Objective To compare the biological characteristics of Culex pipiens pallens resistance to cypermethrin and susceptibility of the species at different temperatures in the laboratory.Methods The growth, reproduction, and life expectancy of two mosquito populations were observed under laboratory conditions at different temperatures (17 ℃, 25 ℃, and 28 ℃ ).Results Culex pipiens pallens had a longer life span at 17 ℃ than at 28 ℃.At the same temperature,adult mosquitoes that were resistant to cypermethrin had a shorter lifespan and quicker development of eggs, larvae, and pupae than did mosquitoes that were susceptible to cypermethrin; differences between resistant and susceptible populations were significant.Mosquito larvae that were susceptible to cypermethrin had a higher mortality rate; differences between resistant and susceptible populations were significant.Conclusion Culex pipiens pallens resistance to cypermethrin results in diminished ability to adapt to environments with different temperatures.%目的 比较实验室内不同温度下淡色库蚊氯氰菊酯抗性品系和敏感品系的生物学特性变化.方法 在17、25和28℃3个不同温度条件下饲养两品系蚊幼虫,观察蚊虫的繁殖、发育及平均寿命等生物学特性.结果 淡色库蚊在17℃条件下发育慢,历期长;在28℃条件下发育快,历期短.同一温度下抗性品系蚊卵、幼虫和蛹的发育历期及成虫寿命均低于敏感品系,卵期死亡率高于敏感品系.结论 淡色库蚊抗氯氰菊酯品系在不同温度下与敏感品系比较均表现出环境适应能力下降.

  9. Host-Feeding Patterns of Native Culex pipiens and Invasive Aedes albopictus Mosquitoes (Diptera: Culicidae) in Urban Zones From Barcelona, Spain

    DEFF Research Database (Denmark)

    Muñoz, Joaquin; Eritja, Roger; Alcaide, Miguel;

    2011-01-01

    The feeding patterns of haematophagous arthropods are of major importance in the ampliÞcation and transmission of infectious disease agents to vertebrate hosts, including humans. The establishment of new vector populations in nonnative range might alter transmission networks. The Asian tiger mosq...

  10. Culex mosquitoes are experimentally unable to transmit Zika virus

    Science.gov (United States)

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

    2016-01-01

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

  11. Evaluación del triflumurón y la mezcla de Bacillus thuringiensis más Bacillus sphaericus para el control de las formas immaduras de Aedes aegypti y culex quinquefasciatus en sumideros en Cali, Colombia

    OpenAIRE

    Pérez Flórez, Mauricio; Giraldo Calderón, Gloria I.; Morales, Carlos A.; Ocampo, Clara Beatriz

    2008-01-01

    Introducción. En Cali los sumideros son uno de los principales criaderos de Aedes aegypti y Culex quinquefasciatus que son controlados por la Secretaría de Salud Municipal utilizando el insecticida triflumurón desde 1999. Se sospecha falla al tratamiento. Objetivos. Evaluar la eficacia del Starycide® (triflumurón) y VectoMax® (mezcla bacteriana de Bacillus thuringiensis var. israelensis y Bacillus sphaericus) en el control de A. aegypti y C. quinquefasciatus en los sumideros y ...

  12. 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).

    Science.gov (United States)

    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.

  13. Toxicological effects of Sphaeranthus indicus Linn. (Asteraceae) leaf essential oil against human disease vectors, Culex quinquefasciatus Say and Aedes aegypti Linn., and impacts on a beneficial mosquito predator.

    Science.gov (United States)

    Chellappandian, Muthiah; Thanigaivel, Annamalai; Vasantha-Srinivasan, Prabhakaran; Edwin, Edward-Sam; Ponsankar, Athirstam; Selin-Rani, Selvaraj; Kalaivani, Kandaswamy; Senthil-Nathan, Sengottayan; Benelli, Giovanni

    2017-04-28

    Use of environmentally friendly, decomposable natural products for effective vector control has gained considerable momentum in modern society. In this study, essential oil of Sphaeranthus indicus (Si-EO) was extracted and further phytochemical screening revealed fourteen compounds with prominent peak area percentage of 24.9 and 22.54% in 3,5-di-tert-butyl-4-hydroxybenzaldehyde and benzene,2-(1,1-dimethylethyl)-1,4-dimethoxy, respectively. The Si-EO was further evaluated for their larvicidal response against Culex quinquefasciatus and Aedes aegypti at different dosages (62.5, 125, 250 and 500 ppm). The Si-EO displayed prominent larvicidal activity at higher concentration (500 ppm) against both species of mosquitoes. The LC50 and LC90 values of oils were observed at 130 and 350 ppm against C. quinquefasciatus larvae and at 140 and 350 ppm against A. aegypti larvae, respectively. Repellent bioassay established higher protection rate at 200 ppm up to 120 min against both the mosquitoes. However, adulticidal response displayed higher mortality rate only at 700 and 800 ppm against C. quinquefasciatus and A. aegypti, respectively. Toxicological screening against mosquito predator Toxorhynchites splendens revealed that the Si-EO was harmless even at the concentration of 1500 ppm. Overall, these results suggest that the Si-EO plays a significant role as a new bio-rational product against ecological burden mosquito vectors which provides an eco-friendly alternative to synthetic pesticides.

  14. 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.

    Science.gov (United States)

    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.

  15. Mosquito larvicidal activity of silver nanoparticles synthesised using actinobacterium, Streptomyces sp. M25 against Anopheles subpictus, Culex quinquefasciatus and Aedes aegypti.

    Science.gov (United States)

    Shanmugasundaram, T; Balagurunathan, R

    2015-12-01

    The present work reports the larvicidal potential of microbially synthesised silver nanoparticles (AgNPs) by using an actinobacterium, Streptomyces sp. M25 isolated from Western Ghats, Tamil Nadu, India. The biomass of Streptomyces sp. was exposed to 1 mM silver nitrate (AgNO3) solution. The synthesis of AgNPs was confirmed by visual inspection followed by instrumental analysis such as UV-vis spectroscopy, fourier transform infrared spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy, scanning electron microscopy, atomic force microscopy and transmission electron microscopy (TEM) with selected area electron diffraction. Based on the TEM and XRD analysis, the average size of the AgNPs was determined to be 10-35 nm. The biosynthesised AgNPs exhibited significant larvicidal activity against malarial vector, Anopheles subpictus (LC50 51.34 mg/L and χ (2) value of 8.228), filarial vector, Culex quinquefasciatus (LC50 48.98 mg/L and χ (2) value of 14.307) and dengue vector, Aedes aegypti (LC50 60.23 mg/L and χ (2) value of 4.042), respectively. Similarly, AgNO3 had larvicidal activity against malarial vector, A. subpictus (LC50 42.544 mg/L and χ (2) value of 2.561), filarial vector, C. quinquefasciatus (LC50 44.922 mg/L and χ (2) value of 1.693) and dengue vector, A. aegypti (LC50 39.664 mg/L and χ (2) value of 5.724), respectively. The current study is a rapid, cost effective, eco-friendly and single step approach. The Streptomyces sp. M25 is a newly added source for the synthesis of AgNPs with improved larvicidal activity.

  16. 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).

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    K Kovendan; K Murugan; S Vincent; Donald R Barnard

    2012-01-01

    ABSTRACT Objective:To determine the mosquito larvicidal activities of hexane, chloroform, ethyl acetate, acetone and methanol leaf extract ofOrthosiphon thymiflorus (O. thymiflorus) againstAnopheles stephensi (An. stephensi), Culex quinquefasciatus (Cx. quinquefasciatus) andAedes aegypti (Ae. aegypti).Methods: The larvicidal activity was assayed against three mosquito species at various concentrations ranging from (50-450 ppm) under the laboratory conditions. TheLC50and LC90value of theO. thymiflorus leaf extract was determined by Probit analysis.Results: The LC50values of hexane, chloroform, ethyl acetate, acetone and methanol extract ofO. thymiflorus third instar larvae ofAn. stephensiwereLC50= 201.39, 178.76, 158.06, 139.22 and118.74 ppm;Cx. quinquefasciatus were LC50=228.13, 209.72, 183.35, 163.55 and149.96 ppm andAe. aegyptiwere LC50=215.65, 197.91, 175.05, 154.80 and137.26 ppm, respectively. Maximum larvicidal activity was observed in the methanolic extract followed by acetone, ethyl acetate chloroform and hexane extract. The larval mortality was observed after24h exposure. No mortality was observed in control.Conclusions:The present results suggest that the effective plant crude extracts have potential to be used as an ideal eco-friendly approach for the control of mosquito vectors. This study provides the first report on the larvicidal activity of this plant crude solvent extract of againstAn. stephensi, Cx. quinquefasciatus andAe. aegyptimosquitoes.

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

    Science.gov (United States)

    Kovendan, K; Murugan, K; Vincent, S; Barnard, Donald R

    2012-04-01

    To determine the mosquito larvicidal activities of hexane, chloroform, ethyl acetate, acetone and methanol leaf extract of Orthosiphon thymiflorus (O. thymiflorus) against Anopheles stephensi (An. stephensi), Culex quinquefasciatus (Cx. quinquefasciatus) and Aedes aegypti (Ae. aegypti). The larvicidal activity was assayed against three mosquito species at various concentrations ranging from (50-450 ppm) under the laboratory conditions. The LC(50) and LC(90) value of the O. thymiflorus leaf extract was determined by Probit analysis. The LC(50) values of hexane, chloroform, ethyl acetate, acetone and methanol extract of O. thymiflorus third instar larvae of An. stephensi were LC(50)= 201.39, 178.76, 158.06, 139.22 and 118.74 ppm; Cx. quinquefasciatus were LC(50)=228.13, 209.72, 183.35, 163.55 and 149.96 ppm and Ae. aegypti were LC(50)=215.65, 197.91, 175.05, 154.80 and 137.26 ppm, respectively. Maximum larvicidal activity was observed in the methanolic extract followed by acetone, ethyl acetate chloroform and hexane extract. The larval mortality was observed after 24 h exposure. No mortality was observed in control. The present results suggest that the effective plant crude extracts have potential to be used as an ideal eco-friendly approach for the control of mosquito vectors. This study provides the first report on the larvicidal activity of this plant crude solvent extract of against An. stephensi, Cx. quinquefasciatus and Ae. aegypti mosquitoes. Copyright © 2012 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  20. Atividade predatória de Helobdella triserialis lineata (Hirudinea: Glossiphonidae sobre formas imaturas de Aedes fluviatilis e Culex quinquefasciatus (Diptera: Culicidae em laboratório Predatory activity of Helobdella triserialis lineata (Hirudinea: Glossiphonidae on immature forms of Aedes ftuviatilis and Culex quinquefasciatus (Diptera: Culicidae in the laboratory

    Directory of Open Access Journals (Sweden)

    Rotraut Anna Gertrud Bohlmann Cônsoli

    1984-10-01

    Full Text Available Foi avaliada a atividade predatória, em laboratório, de Helobdella triserialis lineata (Hirudinea: Glossiphonidae sobre ovos, larvas e pupas de Aedes fluviatilis e Culex quinquefasciatus (Diptera: Culicidae, bem como a influência da presença desses hirudíneos sobre o comportamento de oviposição das fêmeas das duas espécies de mosquitos. Experimentos adicionais foram feitos testando a influência da profundidade da água e da sua salinidade sobre a capacidade predatória dos hirudíneos. Nas condições do experimento, foi observada predação de larvas e pupas, porém não de ovos das duas espécies de dípteros. Número estatisticamente menor de desovas foi depositado por fêmeas de Cx. quinquefasciatus em recipientes que continham hirudíneos, não ocorrendo o mesmo com fêmeas de Ae. fluviatilis. As diferentes profundidades de água testadas não interferiram na atividade predatória de H. t. lineata e somente em concentrações acima de 3% de NaCl essa atividade mostrou-se bastante diminuída.Experiments were conducted to determine the predatory activity of Helobdella triserialis lineata (Hirudinea: Glossiphonidae on eggs, larvae and pupae of Aedes fluviatilis and Culex quinquefasciatus (Diptera: Culicidae in the laboratory, The influence of the leeches on selection, of ovipositing sites by the females of both species of mosquitoes, as well as the role of salinity and water depth in relation to predation were investigated. Larvae and pupae of both species of mosquitoes were efficiently predated, but eggs were not touched. A significantly lower number of eggmasses of Cx. quinquefasciatus were deposited on water containing leeches, but the same did not occur with Ae. fluviatilis. The different depths of water investigated did not interfere with predation and only at concentrations above 3% NaCl was predation considerably diminished.

  1. Emerging Vectors in the Culex pipiens Complex

    Science.gov (United States)

    2004-03-05

    tasks (6, 8–10). Departments of Molecular Cell Biology, Physics of Complex Systems, and Computer Science, Weizmann Institute of Science, Rehovot 76100...Israel. *To whom correspondence should be addressed at Department of Molecular Cell Biology, Weizmann In- stitute of Science, Rehovot 76100, Israel

  2. Growth characteristics of the chimeric Japanese encephalitis virus vaccine candidate, ChimeriVax-JE (YF/JE SA14--14--2), in Culex tritaeniorhynchus, Aedes albopictus, and Aedes aegypti mosquitoes.

    Science.gov (United States)

    Bhatt, T R; Crabtree, M B; Guirakhoo, F; Monath, T P; Miller, B R

    2000-04-01

    The Japanese encephalitis (JE) virus vaccine candidate, ChimeriVax-JE, which consists of a yellow fever (YF) 17D virus backbone containing the prM and E genes from the JE vaccine strain JE SA14--14--2, exhibits restricted replication in non-human primates, producing only a low-level viremia following peripheral inoculation. Although this reduces the likelihood that hematophagous insects could become infected by feeding on a vaccinated host, it is prudent to investigate the replication kinetics of the vaccine virus in mosquito species that are known to vector the viruses from which the chimera is derived. In this study ChimeriVax-JE virus was compared to its parent viruses, as well as to wild-type JE virus, for its ability to replicate in Culex tritaeniorhynchus, Aedes albopictus, and Aedes aegypti mosquitoes. Individual mosquitoes were exposed to the viruses by oral ingestion of a virus-laden blood meal or by intrathoracic (IT) virus inoculation. ChimeriVax-JE virus did not replicate following ingestion by any of the three mosquito species. Additionally, replication was not detected after IT inoculation of ChimeriVax-JE in the primary JE virus vector, Cx. tritaeniorhynchus. ChimeriVax-JE exhibited moderate growth following IT inoculation into Ae. aegypti and Ae. albopictus, reaching titers of 3.6-5.0 log(10) PFU/mosquito. There was no change in the virus genotype associated with replication in mosquitoes. Similar results were observed in mosquitoes of all three species that were IT inoculated or had orally ingested the YF 17D vaccine virus. In contrast, all mosquitoes either IT inoculated with or orally fed wild-type and vaccine JE viruses became infected, reaching maximum titers of 5.4-7.3 log(10) PFU/mosquito. These results indicate that ChimeriVax-JE virus is restricted in its ability to infect and replicate in these mosquito vectors. The low viremia caused by ChimeriVax-JE in primates and poor infectivity for mosquitoes are safeguards against secondary spread

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Oswaldo Paulo Forattini

    1973-12-01

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

  8. The research on the killing effect of insecticides mixed with synergist for Culex pipiens pallens larvae in field%杀虫剂与增效剂混用对现场淡色库蚊幼虫的杀灭效果

    Institute of Scientific and Technical Information of China (English)

    李士根

    2009-01-01

    目的 探讨杀虫剂与增效剂混用对现场淡色库蚊幼虫的杀灭效果,为合理有效地进行蚊虫化学防治提供依据. 方法 参照WHO生物测定方法和唐振华药物联合作用试验方法,将敌敌畏、残杀威、氯氰菊酯分别与氧化胡椒基丁醚(S1)、八氯二丙醚(S2)、增效胺(MGK264)混用,测试3个现场淡色库蚊种群幼虫死亡率,计算增效系数. 结果 敌敌畏与S1、S2和MGK264混用的增效系数依次为255.44~617.60、416.24~1 475.97和109.40~173.30,残杀威与S1、S2和MGK264混用的增效系数依次为335.27~487.95、329.56~948.79和122.08~187.23,氯氰菊酯与S1、S2和MGK264混用的增效系数依次为304.15~471.35、232.24~252.65和246.95~404.40. 结论 杀虫剂与增效剂混用可对现场淡色库蚊幼虫起到明显的杀虫增效作用,选择杀虫效力较强的配方可提高蚊虫防制效果.%Objective To study the effect of insecticide mixed with synergist to kill Calex pipiens pal-lens larvae in field and provide a scientific and rational basis for the chemical prevention and control of mosqui-to. Methods According to WHO bioassay method and Tang Zhenhua unification drug test method, diehlor-vos, propoxur and cypermethrin were mixed with oxidation piperonyl butoxide (S1), octachlorodipropyl ether (S2) and synergy amine (MGK264) respectively, then bioassay was tested on Culex pipiens pallens larvae at 3 spots in field and the synergism coefficients were calculated. Results The synergism coefficient of dich]orves mixed with S1, S2 and MGK264 were 255.44-617.60,416.24-1 475.97 and 109.40-173.30 respectively. The synergism coefficient of propoxur mixed with S1 , S2 and MGK264 were 335.27-487.95, 329.56-948.79 and 122.08-187.23 respectively. The synergism coefficient of cypermethrin mixed with S1 , S2 and MGK264 were 304.15-471.35,232.24-252.65 and 246.95-404.40 respectively. Conclusion The obvious synergy effects were observed in the mixture of pesticides and

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

    OpenAIRE

    Jackson, Bryan Tyler

    2004-01-01

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

  10. A 2-yr Mosquito Survey Focusing on Aedes koreicus (Diptera: Culicidae) in Northern Italy and Implications for Adult Trapping.

    Science.gov (United States)

    Baldacchino, F; Montarsi, F; Arnoldi, D; Barategui, C; Ferro Milone, N; Da Rold, G; Capelli, G; Rizzoli, A

    2017-05-01

    Aedes koreicus (Edwards) is an invasive mosquito species, like Aedes albopictus (Skuse) and Aedes japonicus japonicus (Theobald), that has already colonized a large part of northeastern Italy and other European countries. Despite its rapid expansion, information about adult distribution and trapping is lacking. Here, we conducted a 2-yr longitudinal survey using adult traps to investigate the spatiotemporal distribution of Ae. koreicus and evaluated the effectiveness of three trapping devices in Latin square experiments conducted in an urban site and a forested site. The following three different traps were compared: a CO2-baited Biogents (BG) Sentinel trap, a CO2-baited Centers for Disease Control and Prevention light trap (CDC trap), and a grass infusion-baited gravid trap.In northern Italy, Ae. koreicus was collected from late April to early November, with peak of abundance observed in August. Aedes koreicus was more abundant in 2015 than in 2014 because of higher temperatures during summer. Unlike Ae. albopictus, the abundance of Ae. koreicus was not related to the altitude of the sampling locations in the range 241-660 m above sea level. The BG Sentinel and gravid traps collected significantly more Ae. koreicus than the CDC trap in the urban site, whereas there was no significant difference between the three traps in the forested site. In the urban site, the BG Sentinel trap and the gravid trap were the most effective for collecting Ae. albopictus and Culex pipiens L., respectively. In the forested site, Cx. pipiens was primarily collected by the CDC trap. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Japanese encephalitis virus detected in Culex pipiens pallens for the first time in Tianjin%天津市首次从淡色库蚊检测出基因Ⅰ型流行性乙型脑炎病毒

    Institute of Scientific and Technical Information of China (English)

    吴彤宇; 李力; 秦娜; 杨东靖; 吕莉琨

    2012-01-01

    Objective To investigate the status of mosquitoes carrying Japanese encephalitis (JE) virus in some parts of Tianjin, providing the basis for the control and prevention of JE. Methods The light trap method was used to collect mosquitoes twice a month from July 2010 to September 2010 in Tianjin. Reverse transcription - polymerase chain reaction (RT-PCR) detection was done and the amplified target fragments were sequenced. The evolutionary tree was built with the Mega 4.0 software by the O-linked method. Results A total of 10 285 adult mosquitoes, which belonged to 2 generaes and 3 species (Culex pipiens pollens, Cx. tritaeniorhynchus, and Anopheles sinensis) were captured. Molecular identification showed that the Cx. pipiens pallens was infected with JE viruses, identified by genotyping as JE virus type I and named TJ01 (HQ718463). Conclusion There exists mosquito infection with JE virus type I in Tianjin, which is close to the JE viruses isolated in Shanghai in terms of their evolution.%目的 调查天津市部分地区蚊虫携带流行性乙型脑炎(乙脑)病毒状况,为乙脑防治提供依据.方法 2010年7-9月,使用灯诱法,每月在天津市5个区(县)采集蚊虫2次,用RT-PCR检测乙脑病毒核酸;扩增的目标片段进行序列测定;用Mega 4.0软件以邻位相连法构建进化树.结果 共捕获成蚊10285只,2属3种(淡色库蚊、三带喙库蚊、中华按蚊),一组淡色库蚊样品,经分子生物学鉴定呈乙脑病毒感染阳性,命名为TJ01( HQ718463),基因分型为Ⅰ型乙脑病毒.结论 天津市蚊虫中存在基因Ⅰ型乙脑病毒感染,与上海市乙脑病毒分离株进化关系较近.

  12. 咸阳市淡色库蚊对5种杀虫剂的抗药性研究及防制对策%Resistance of Culex pipiens pallens to five insecticides in Xianyang city and the corresponding control strategies

    Institute of Scientific and Technical Information of China (English)

    孙亮; 吕文; 孙养信

    2012-01-01

    Objective To identify the resistance of Culex pipiens pattens to five commonly used insecticides in Xianyang city so as to provide evidence for control strategy development. Methods The mortality of larvae exposed to five insecticides was determined by the distinguishing dosage method. Results The resistance level of Cx. Pipwns pattens was high under the diagnosis dose to DDT, DDVP, permethrin, and deltamethrin, and the mortality in 24 hours was 23.45%, 14.02%, 28.77%, 25.00%, respectively. The resistance to cypermethrin was moderate and the mortality was 58.63%. Conclusion The resistance of Cx. Pipiens pallens to five commonly used insecticides in Xianyang has reached middle to high levels. Different kinds of insecticides should be used for control of mosquitoes.%目的 了解咸阳市淡色库蚊对5种杀虫剂的抗药性现状,为制定防制对策提供科学依据.方法 采用区分剂量法测定淡色库蚊幼虫对5种杀虫剂的24 h死亡率.结果 咸阳市淡色库蚊对DDT、敌敌畏、氯菊酯和溴氰菊酯的抗性均达到高抗以上,24 h死亡率分别为23.45%、14.02%、28.77%和25.00%;对氯氰菊酯的抗性达到中抗以上,24 h死亡率为58.63%.结论 咸阳市淡色库蚊对5种杀虫剂均产生了不同程度的抗药性,今后在这些地区进行蚊虫防治时应考虑换用其他种类的杀虫剂.

  13. Multiple insecticide resistances and kdr mutation of Culex pipiens pallens in north-central Anhui Province%安徽省中北部淡色库蚊对多种杀虫剂抗性及其kdr基因突变研究

    Institute of Scientific and Technical Information of China (English)

    魏星; 杨小迪; 王小莉; 李江艳; 王媛媛; 夏惠; 常雪莲; 方强

    2016-01-01

    Objective To understand the status of resistance to multiple insecticides and the frequencies of kdr mutations in Culex pipiens pallens from north⁃central Anhui Province. Methods From July to September,2014,the C. pipiens pallens mosquito larvae were collected in Huaibei,Bengbu and Chuzhou cities of the north⁃central Anhui Province and reared to adults. The female adult mosquitoes at 3-5 days post emergence were tested for susceptibility to the four insecticides,namely 0.05%deltamethrin,5%malathion,0.1%bendiocarb and 4%DDT,by using the standard WHO resistance tube bioassay. The detec⁃tion of the point mutations of the kdr gene at codon 1014 was conducted by PCR and DNA sequencing in the deltamethrin⁃resis⁃tant and⁃susceptible mosquitoes. Results High levels of resistance to all the four insecticides were found in all the three tested populations,although mosquito mortality varied among populations and test insecticides. Among the test insecticides,DDT showed lowest mortality with no significant difference(F=1.027,P>0.05)in all test populations,whereas significantly differ⁃ent mortalities were observed among populations for the remained three insecticides tested(deltamethrin,malathion,and ben⁃diocarb)(F = 23.823,33.955,128.841;all P 0.05);但接触溴氰菊酯、马拉硫磷、噁虫威后的死亡率差异均有统计学意义(F=23.823、33.955、128.841,P均<0.01)。3地淡色库蚊种群的kdr基因1014位点均存在L1014F、L1014S这2种非同义突变;L1014F突变频率与溴氰菊酯抗性水平呈正相关(r2=0.718,P<0.01)。结论安徽省中北部地区淡色库蚊对溴氰菊酯、马拉硫磷、噁虫威、DDT均产生了较强的抗性,kdr基因L1014F突变频率与溴氰菊酯抗性水平呈正相关;各地区卫生部门需加强对媒介蚊虫抗性的动态监测。

  14. The cross-resistance of DDVP-resistant and cypermethrin-resistant strains of Culex pipiens pallens to the common chemical pesticides%淡色库蚊敌敌畏抗性和氯氰菊酯抗性品系对常用化学杀虫剂的交互抗性

    Institute of Scientific and Technical Information of China (English)

    李向东; 李士根; 章洪华; 刘永春; 王新国; 王怀位

    2015-01-01

    Objective To investigate the cross-resistance of Culex pipiens pallens to common pesticidesso as to provide a basis for the rational use of chemical pesticides.Methods The sensitivity of sensitive,dichlorvos (DDVP)-resistant and cypermethrin-resistant strains of Culex pipiens pallens Ⅳ instar larvae to six common chemical pesticides (acetofenate,DDVP,malathion,propoxur,cypermethrin and deltamethrin) was detected based on WHO bioassay method.Seven concentrations were set up for each experiment.Two groups were set up for each concentration and each group had 25 larvae.The dead larvae were detected after 24 h exposure.The median lethal concentration (LC50),regression equations and resistance indices were then calculated.Results The LC50 of DDVP-resistant strain of Culex pipiens pallens to acetofenate,DDVP,malathion,propoxur,eypermethrin and deltamethrin were 1.962 3 mg/L,1.160 7 mg/L 0.735 9 mg/L,0.900 2 mg/L,0.022 0 mg/L and 0.000 1 mg/L respectively.And the regression equations for them were Y=3.528 7+ 5.025 4X,Y=4.696 2+4.693 7X,Y=5.505 1+3.853 6X,Y=5.235 0+5.147 6X,Y=10.499 5+3.318 4X and Y=13.297 7+2.168 3Xrespectively.The resistance indices for them were 9.25,12.17,9.14,7.93,183.47 and 0.71respectively.The LC50 of cypermethrin-resistant strain of Culex pipiens pallens to acetofenate,DDVP,malathion,propoxur,cypermethrin and deltamethrin were 5.572 8 mg/L,0.246 4 mg/L,0.089 2 mg/L,0.202 7 mg/L,0.064 1 mg/L and 0.008 5 mg/Lrespectively.The regression equations for them were Y=2.772 8+2.985 2X,Y=7.205 4+3.626 0X,Y=9.475 1+4.263 5X,Y=6.810 6+2.612 5X,Y=8.740 4+3.135 2X and Y=14.695 1+4.685 3X respectively.The resistance indices for them were 26.27,2.58,1.10,1.79,534.31 and 40.60 respectively.Conclusion Mosquito will generate resistance when using one kind of chemical pesticide in a long time.It will also generate different levels of cross-resistance to other pesticides.So when using chemical pesticides,we should take measures such as rationally selecting chemical

  15. Pesticidal and Mosquitocidal Activities of Clausena excavata Burm. F. (Rutaceae against Spodoptera litura (Fab. (Noctuidae: Lepidoptera and Aedes aegypti L., Anopheles stephensi Liston, and Culex quinquefasciatus Say. (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Mathivanan Thangarasu

    2014-01-01

    Full Text Available The aim of this paper is to evaluate the larvicidal and ovicidal activities of hexane, diethyl ether, dichloromethane, ethyl acetate, and methanol extract of Indian medicinal plant, Clausena excavata, at different concentrations against lepidopteran agricultural field pest, Spodoptera litura (Lepidoptera: Noctuidae, and Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus (Diptera: Culicidae. Twenty-five early fourth instar larvae of S. litura and A. aegypti, An. stephensi and C. quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using specific protocols. The 24 h LC50 and LC90 values of the C. excavata leaf extract was determined by probit analysis. The ovicidal activity were determined against S. litura and A. aegypti, An. stephensi, and C. quinquefasciatus and was assessed 120 hrs after treatment. Results of this study show that the selected Indian medicinal plant C. excavata may be a potential source of natural larvicidal and ovicidal activities against selected pest and vector mosquitoes.

  16. Studies on effects ofAndrographis paniculata (Burm.f.) andAndrographis lineata nees (Family:Acanthaceae) extracts against two mosquitoesCulex quinquefasciatus (Say.) andAedes aegypti (Linn.)

    Institute of Scientific and Technical Information of China (English)

    Renugadevi G; Ramanathan T; Shanmuga priya R; Thirunavukkarasu P

    2013-01-01

    Objective:To investigate the studies on effects ofAndrographis paniculata(A. paniculata) (Burm.f.) andAndrographis lineata(A. lineata) nees(Family:Acanthaceae) extracts against two mosquitoesCulex quinquefasciatus(Cx. quinquefasciatus)(Say.) andAedes aegypti(Ae. aegypti) (Linn.).Methods:The aqueous and petroleum ether extracts of two plant species,A. paniculata andA. lineate were examined against the larvae ofA. aegypti(L.) andCx. quinquefasciatus with gradually increasing concentrationie. from50 to200 ppm of solvent extracts and to test their activity in combination with each other.Results:In a24 h bioassay experiment with plant extracts, highest mortalities were recorded at200 ppm of concentrations for leaves ofA. lineta andA. paniculata individually.For combination effect, only150 ppm of the mixture of solvent extracts of petroleum ether: aqueous(1:1) extracts showed100% mortality after24 h of exposure. Conclusions:The results show that, insecticides of plant combination is ecofriend and has better larvicidal activity compared to individual extracts.

  17. Evaluation of vector competence for West Nile virus in Italian Stegomyia albopicta (=Aedes albopictus) mosquitoes.

    Science.gov (United States)

    Fortuna, C; Remoli, M E; Severini, F; Di Luca, M; Toma, L; Fois, F; Bucci, P; Boccolini, D; Romi, R; Ciufolini, M G

    2015-12-01

    West Nile virus (WNV) is a zoonotic arboviral pathogen transmitted by mosquitoes in a cycle that involves wild birds as reservoir hosts. The virus is responsible for outbreaks of viral encephalitis in humans and horses. In Europe, Culex pipiens (Diptera: Culicidae) is considered to be the main vector of WNV, but other species such as Stegomyia albopicta (=Aedes albopictus) (Diptera: Culicidae) may also act as competent vectors of this virus. Since 2008 human cases of WNV disease have been reported in northeast Italy. In 2011, new areas of southern Italy became involved and a first outbreak of WNV lineage 1 occurred on the island of Sardinia. On the assumption that a potential involvement of St. albopicta in WNV transmission cannot be excluded, and in order to evaluate the competence of this species for the virus, an experimental infection of an St. albopicta laboratory colony, established from mosquitoes collected in Sardinia, was carried out. The results were compared with those obtained in a colony of the main vector Cx. pipiens. The study showed St. albopicta collected on Sardinia to be susceptible to WNV infection, which suggests this Italian mosquito species is able to act as a possible secondary vector, particularly in urban areas where the species reaches high levels of seasonal abundance.

  18. 致乏库蚊幼虫摄食和消化鱼腥藻的观察%THE OBSERVATION OF FEEDING ABILITY OF CULEX PIPIEN FATIGANS LARVAE ON ANABAENA

    Institute of Scientific and Technical Information of China (English)

    张世萍; 王方雨; 朱艳芳; 但丽; 喻子牛

    2005-01-01

    Under the laboratory condition, the larvae of Culex pipens fatigans may feed mainly on Anabaena sp and complete their life cycle. The retention time of Anabaena sp. in larval intestine is about 6 hours while that of Saccharomyces sp. is about 5hours, meaning that Anabaena sp. is not so digestible for the larvae. From hatching to pupation, the larvae fed with Anabaena sp. lasted 194 hours and those fed with Saccharomyces sp were 142 hours, showing that the duration for completing larval stage of the former is 52 hours, which is longer than those fed on Saccharomyces.%在实验室条件下,致乏库蚊幼虫可大量摄食鱼腥藻,并能消化利用,完成生活史.鱼腥藻在蚊幼虫肠道中滞留时间约6h,酵母约5h,鱼腥藻比酵母稍难消化.蚊幼虫至化蛹时期相比,饲喂鱼腥藻为194h,而饲喂酵母的为142h,饲喂鱼腥藻比饲喂酵母延缓了蚊幼虫期52h.

  19. Systematics of Aedes Mosquitoes Project.

    Science.gov (United States)

    1986-01-01

    97% of the total are Aedes, Anopheles, and Culex , and a good series of all stages (male, female, larva, and pupa ) were obtained for most species of...Is. SUPPLEMENTARY NOTES 19. KEY WORDS (Continue on reverse side If necessary and tdentify by block number) Mosquitoes Africa Aedes Culicidae...entomologists with keys , necessary literature, and other identification guides, to the loan of specialized .0 collecting and rearing equipment, which cannot be

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

    Science.gov (United States)

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

    2010-01-01

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

  1. STUDY ON THE ROLE OF NON-SPECIFIC ESTERASE OF CULEX PIPIENS PALLENS IN RESISTANCE AGAINST DIFFERENT INSECTICIDES%非特异性酯酶在淡色库蚊对不同杀虫剂抗性中的作用研究

    Institute of Scientific and Technical Information of China (English)

    李士根; 张昕; 甄天民; 郭永和; 刘永春; 刘凤梅

    2001-01-01

    Objective To explore the role of non-specific esterase (NSE) of Culex pipiens pallens in resistance against insecticides. Methods Laboratory detection of NSE was performed for 5 strains of the mosquito using β-Naphthyl acetate as the substrate and fast blue B salt solution as the color agent. Results NSE level was highest in anti-DDVP strain, followed by anti-DDVP degenerated strain and anti-propoxur strain, while the level of NSE of anti-cypermethrin was similar to that of susceptible strain. Conclusion NSE was showed to play important role in the mosquito resistance against organophosphorus insecticides and was one of important mechanism for the development of resistance towards carbamates, while it has little relation with the resistance against pyrethroids.%目的 探讨非特异性酯酶(Non-specific esterase,NSE)在淡色库蚊对不同杀虫剂抗性中的作用。 方法 以β-乙酸萘酯为底物,坚固蓝B盐为显色剂,测定室内5个品系淡色库蚊的NSE活力。 结果 5个品系淡色库蚊中以抗DDVP品系NSE活力水平最高,其次为抗DDVP降解品系和抗残杀威品系。抗氯氰菊酯品系较低,与敏感品系相近。 结论 NSE在淡色库蚊对有机磷类杀虫剂的抗性中起重要作用,也是对氨基甲酸酯类杀虫剂产生抗性的机制之一,与对拟除虫菊酯类杀虫剂的抗性关系不大。

  2. UJI COBA STRAIN LOKAL BACILLUS THURINGIENSIS H-14 YANG DITUMBUHKAN DALAM MEDIA AIR KELAPA TERHADAP JENTIK NYAMUK ANOPHELES ACONITUS DAN CULEX PIPIENS QUINQUEFASCIATUS PERANGKAP SENTINEL DI KOLAM KOTAMADIA SALATIGA

    Directory of Open Access Journals (Sweden)

    Blondie Ch. P.

    2012-09-01

    Full Text Available An investigation was conducted on Bacillus thuringiensis H-14 local strain grown in coconut water media and Tryptose Phosphate Broth (TPB. The two media were tested against Anopheles aconitus and Culex p. quinquefasciatus mosquito larvae in the Vector Control Research Station laboratory and in Sentinel traps village Kauman Kidul pool, Salatiga. The pathogenicity test on B. thuringiensis H-14 local strain grown in coconut water and TPB against An. aconitus and Cx. p. quinquefasciatus larvae in the laboratory was done according to WHO procedure. This was conducted to determine the LC50 and LC90 which is counted according to the probit analysis. The pathogenicity test result of B. thuringiensis H-14 local strain cultured in coconut water against An. aconitus and Cx. p. quinquefasciatus larvae at 24 hours of exposure, showed the LC50 were 0,04 ml/100ml and 0,10 ml/100ml with LC90 were 0,15 ml/100ml and 0,20 ml/100ml respectively. The pathogenicity test at 48 hours of exposure showed the LC50 were 0,01 ml/100ml and 0,02 ml/100ml with LC90 were 0,04 ml/100 ml and 0,13 ml/100 ml respectively. The pathogenicity test result o/B. thuringiensis H-14 local strain cultured in TPB media against An. aconitus and Cx. p. quinquefasciatus larvae at 24 hours exposure, showed the LC50 were 0,05 ml/100 ml and 0,06 ml/100 ml with LC90 were 0,20 ml/100 ml and 0,15 ml/100 ml respectively. The pathogenicity test at 48 hours of exposure showed the LC50 were 0,02 ml/100 ml and 0,03 ml/100ml with LC90 were 0,10 ml/100 ml and 0,08 ml/100ml respectively. The field trial showed the patogenicity test result of B. thuringiensis H-14 local strain cultured in coconut water media against An. aconitus larvae at Sentinel trap in r icefield pools, showed a mortality of more than 50% for 4 days at the 0,15 ml/100 ml (LC90 aplication dosage. The pathogenicity against Cx. p. quinquefasciatus larvae at Sentinel trap was more than 50% for 3 days at the 0,20 ml/100 ml (LC90 aplication

  3. 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).

    Science.gov (United States)

    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), 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.

  4. Crouching tiger, hidden trouble: urban sources of Aedes albopictus (Diptera: Culicidae refractory to source-reduction.

    Directory of Open Access Journals (Sweden)

    Isik Unlu

    Full Text Available Our ultimate objective is to design cost-effective control strategies for Aedes albopictus, the Asian tiger mosquito, an important urban nuisance and disease vector that expanded worldwide during the last 40 years. We conducted mosquito larval surveys from May through October 2009 in the City of Trenton, New Jersey, USA, while performing intensive monthly source-reduction campaigns that involved removing, emptying, or treating all accessible containers with larvicides and pupicides. We examined patterns of occurrence of Ae. albopictus and Culex pipiens, another urban mosquito, among different container types by comparing observed and expected number of positive containers of each type. Expected use was based on the relative frequency of each container type in the environment. Aedes albopictus larvae and pupae were found significantly more often than expected in medium volumes of water in buckets and plant saucers but were rarely collected in small volumes of water found in trash items such as discarded cups and cans. They were also absent from large volumes of water such as in abandoned swimming pools and catch basins, although we consistently collected Cx. pipiens from those habitats. The frequency of Ae. albopictus in tires indicated rapid and extensive use of these ubiquitous urban containers. Standard larval-based indices did not correlate with adult catches in BG-Sentinel traps, but when based only on Ae. albopictus key containers (buckets, plant saucers, equipment with pockets of water, and tires they did. Although we found that only 1.2% of the 20,039 water-holding containers examined contained immature Ae. albopictus (5.3% if only key containers were counted, adult populations were still above nuisance action thresholds six times during the 2009 mosquito season. We conclude that in urban New Jersey, effective source reduction for Ae. albopictus control will require scrupulous and repeated cleaning or treatment of everyday use containers

  5. Crouching tiger, hidden trouble: urban sources of Aedes albopictus (Diptera: Culicidae) refractory to source-reduction.

    Science.gov (United States)

    Unlu, Isik; Farajollahi, Ary; Strickman, Daniel; Fonseca, Dina M

    2013-01-01

    Our ultimate objective is to design cost-effective control strategies for Aedes albopictus, the Asian tiger mosquito, an important urban nuisance and disease vector that expanded worldwide during the last 40 years. We conducted mosquito larval surveys from May through October 2009 in the City of Trenton, New Jersey, USA, while performing intensive monthly source-reduction campaigns that involved removing, emptying, or treating all accessible containers with larvicides and pupicides. We examined patterns of occurrence of Ae. albopictus and Culex pipiens, another urban mosquito, among different container types by comparing observed and expected number of positive containers of each type. Expected use was based on the relative frequency of each container type in the environment. Aedes albopictus larvae and pupae were found significantly more often than expected in medium volumes of water in buckets and plant saucers but were rarely collected in small volumes of water found in trash items such as discarded cups and cans. They were also absent from large volumes of water such as in abandoned swimming pools and catch basins, although we consistently collected Cx. pipiens from those habitats. The frequency of Ae. albopictus in tires indicated rapid and extensive use of these ubiquitous urban containers. Standard larval-based indices did not correlate with adult catches in BG-Sentinel traps, but when based only on Ae. albopictus key containers (buckets, plant saucers, equipment with pockets of water, and tires) they did. Although we found that only 1.2% of the 20,039 water-holding containers examined contained immature Ae. albopictus (5.3% if only key containers were counted), adult populations were still above nuisance action thresholds six times during the 2009 mosquito season. We conclude that in urban New Jersey, effective source reduction for Ae. albopictus control will require scrupulous and repeated cleaning or treatment of everyday use containers and extensive

  6. Crouching Tiger, Hidden Trouble: Urban Sources of Aedes albopictus (Diptera: Culicidae) Refractory to Source-Reduction

    Science.gov (United States)

    Unlu, Isik; Farajollahi, Ary; Strickman, Daniel; Fonseca, Dina M.

    2013-01-01

    Our ultimate objective is to design cost-effective control strategies for Aedes albopictus, the Asian tiger mosquito, an important urban nuisance and disease vector that expanded worldwide during the last 40 years.  We conducted mosquito larval surveys from May through October 2009 in the City of Trenton, New Jersey, USA, while performing intensive monthly source-reduction campaigns that involved removing, emptying, or treating all accessible containers with larvicides and pupicides. We examined patterns of occurrence of Ae. albopictus and Culex pipiens, another urban mosquito, among different container types by comparing observed and expected number of positive containers of each type. Expected use was based on the relative frequency of each container type in the environment. Aedes albopictus larvae and pupae were found significantly more often than expected in medium volumes of water in buckets and plant saucers but were rarely collected in small volumes of water found in trash items such as discarded cups and cans. They were also absent from large volumes of water such as in abandoned swimming pools and catch basins, although we consistently collected Cx. pipiens from those habitats. The frequency of Ae. albopictus in tires indicated rapid and extensive use of these ubiquitous urban containers. Standard larval-based indices did not correlate with adult catches in BG-Sentinel traps, but when based only on Ae. albopictus key containers (buckets, plant saucers, equipment with pockets of water, and tires) they did. Although we found that only 1.2% of the 20,039 water-holding containers examined contained immature Ae. albopictus (5.3% if only key containers were counted), adult populations were still above nuisance action thresholds six times during the 2009 mosquito season. We conclude that in urban New Jersey, effective source reduction for Ae. albopictus control will require scrupulous and repeated cleaning or treatment of everyday use containers and extensive

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

    Science.gov (United States)

    Reisen, William K

    2012-12-01

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

  8. SUSCEPTIBILITY OF TWO DIFFERENT STRAINS OF CULEX PIPIENS PALLENS (DIPTERS: CULICIDAE) TO EIGHT PLANT EXTRACTS%8种植物提取物对2种不同品系淡色库蚊的敏感性研究

    Institute of Scientific and Technical Information of China (English)

    孙立新; 丁永健; 马磊; 孙艳; 董慧琴; 朱昌亮

    2009-01-01

    目的 研究开发有效的天然植物杀虫剂. 方法按照WHO推荐的蚊幼虫敏感性测定方法,用8种植物的叶、茎、果和皮等提取物,对野生和敏感2个品系淡色库蚊进行敏感性测定. 结果 银杏外果皮提取物对淡色库蚊2个品系杀虫效果最强,其次为三尖杉和水杉,其他5种植物(重阳木、乌桕、香椿、杜仲和山茱萸)杀虫效果较弱.随后用银杏外果皮提取物对淡色库蚊卵、幼虫、蛹进行毒力测定,结果表明,Ⅰ龄幼虫最敏感,其次为Ⅱ龄、Ⅲ龄和Ⅳ龄幼虫.银杏外果皮提取物对敏感品系Ⅰ龄、Ⅱ龄、Ⅲ龄和Ⅳ龄的LC50分别为2.52、8.62、3.3 和 18.6 mg/L;对野生品系Ⅰ龄、Ⅱ龄、Ⅲ龄和Ⅳ龄的LC50分别为7.4、15.2、19.2和 25.0 mg/L,明显高于敏感品系.银杏外果皮提取物在5~100 mg/L浓度范围内不影响卵的孵化,在100 mg/L以上时,影响蛹的羽化. 结论 8种植物提取物对淡色库蚊的敏感性各不相同,银杏外果皮提取物有明显的杀幼效果,值得进一步研究和开发.%Objective To study effective and affordable natural insecticides. Methods The insecticidal activities of essential oil extracts from leaves, barks, fruits and exocarps of eight plants against the susceptible and field strains of the fourth instar larvae of the mosquito Culex pipiens pallens were determined by following the standard World Health Organization larval susceptibility test methods. Results Extract of Ginkgo exocarps is the most toxic, followed by extracts of Cephalotaxaceae and Metasequoia. Other five plants (Chinese Bishopwood, China Tallowtree, China Toona, Eucommia and Fructus Corni) have limited effect against these two strains of Cx. pipiens pallens. Toxicity of extract of Ginkgo exocarps to the eggs, larvae and pupae of the two strains of Cx. pipiens pallens was studied in succession. The most susceptible developmental stage of mosquito is the 1st instar, followed by the 2nd, 3rd and 4th instar. The

  9. Experimental transmission of Zika virus by mosquitoes from central Europe.

    Science.gov (United States)

    Heitmann, Anna; Jansen, Stephanie; Lühken, Renke; Leggewie, Mayke; Badusche, Marlis; Pluskota, Björn; Becker, Norbert; Vapalahti, Olli; Schmidt-Chanasit, Jonas; Tannich, Egbert

    2017-01-12

    Mosquitoes collected in Germany in 2016, including Culex pipiens pipiens biotype pipiens, Culex torrentium and Aedes albopictus, as well as Culex pipiens pipiens biotype molestus (in colony since 2011) were experimentally infected with Zika virus (ZIKV) at 18 °C or 27 °C. None of the Culex taxa showed vector competence for ZIKV. In contrast, Aedes albopictus were susceptible for ZIKV but only at 27 °C, with transmission rates similar to an Aedes aegypti laboratory colony tested in parallel. This article is copyright of The Authors, 2017.

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

    Science.gov (United States)

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

    2015-03-01

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

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

    Science.gov (United States)

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

    2002-09-01

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

  12. Larvicidal activity of titanium dioxide nanoparticles synthesized using Morinda citrifolia root extract against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus and its other effect on non-target fish

    Directory of Open Access Journals (Sweden)

    Thodhal Yoganandham Suman

    2015-03-01

    Full Text Available Objective: To assess the larvicidal activity of titanium dioxide nanoparticles (TiO 2NPS synthesized from the root aqueous extract of Morinda citrifolia (M. citrifolia against the larvae of Anopheles stephensi (An. stephensi, Aedes aegypti (Ae. aegypti and Culex quinquefasciatus (Cx. quinquefasciatus. Methods: The M. citrifolia broth solution was prepared by taking 8 g of the powdered root of M. citrifolia in 250 mL Erlenmeyer flask along with 100 mL of distilled water and boiled for 5 min. About 20 mL of M. citrifolia root extract was added into the 80 mL of an aqueous solution of 5 mmol/L TiO(OH2 for the reduction under continuous stirring for 4 h at 50 °C. Synthesized TiO2NPS were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. X-ray diffraction confirmed the crystalline nature of the nanoparticles. Toxicity studies were carried out against non-target fish species Poecilia reticulata, the most common organism in the habitats of An. stephensi, Ae. aegypti and Cx. quinquefasciatus. Results: The Fourier transform infrared spectroscopy for TiO2NPS synthesized by M. citrifolia root extract showed band at 3 426 cm-1, 1 637 cm-1 and 714 cm-1. The 3 426 cm-1 showed O-H stretching due to alcoholic group; 1 637 cm-1 showed N-H bend due to alcoholic group. In particular, the 1 637 cm-1 indicated the presence of H bend bond for 1° for proteins. A peak was observed around 714 cm-1 due to Ti-O-O bond. Field emission scanning electron microscopy and transmission electron microscopy showed the spherical nature of the nanoparticles with a size of 20.46-39.20 nm. The biosynthesized TiO2NPS showed maximum activity against the larvae of An. stephensi, Ae. aegypti and Cx. quinquefasciatus when compared to the aqueous extract of M. citrifolia. Toxicity studies revealed no toxicity towards Poecilia reticulata at LC50 and LC90 doses of TiO 2NPS

  13. α-Humulene and β-elemene from Syzygium zeylanicum (Myrtaceae) essential oil: highly effective and eco-friendly larvicides against Anopheles subpictus, Aedes albopictus, and Culex tritaeniorhynchus (Diptera: Culicidae).

    Science.gov (United States)

    Govindarajan, Marimuthu; Benelli, Giovanni

    2016-07-01

    Mosquitoes transmit serious pathogens and parasites to humans and animals, including malaria, dengue, Japanese encephalitis and filariasis. The extensive use of chemical pesticides leads to the development of resistance in mosquito vector populations and serious non-target effects on human health and the environment. Myrtaceae plants can be a useful reservoir of natural products effective against Culicidae young instars. In this research, we evaluated the mosquitocidal potential of the essential oil (EO) from Syzygium zeylanicum leaves against larvae of three mosquitoes of medical and veterinary importance, the malaria vector Anopheles subpictus, the dengue vector Aedes albopictus, and the Japanese encephalitis vector Culex tritaeniorhynchus. The chemical composition of the EO was analyzed by gas chromatography-mass spectroscopy. GC-MS revealed that the S. zeylanicum EO contained at least 18 compounds. The major chemical components were α-humulene (37.8.5 %) and β-elemene (10.7 %). The EO had a significant toxic effect against early third-stage larvae of An. subpictus, Ae. albopictus, and Cx. tritaeniorhynchus, with LC50 values of 83.11, 90.45, and 97.96 μg/ml, respectively. The two major constituents extracted from the S. zeylanicum EO were tested individually for acute toxicity against larvae of the three mosquito vectors. α-Humulene and β-elemene appeared highly effective against An. subpictus (LC50 = 6.19 and 10.26 μg/ml, respectively), followed by Ae. albopictus (LC50 = 6.86 and 11.15 μg/ml) and Cx. tritaeniorhynchus (LC50 = 7.39 and 12.05 μg/ml). Furthermore, the EO and its major components was safe towards the non-target fish Gambusia affinis; LC50 values were 20374.26, 1024.95, and 2073.18 μg/ml, respectively for EO, α-humulene and β-elemene. Overall, this study highlighted that the acute toxicity of S. zeylanicum EO towards mosquito larvae was mainly due to the presence of α-humulene and β-elemene. Furthermore, we pointed

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

    Science.gov (United States)

    Fischer, Sylvia; Schweigmann, Nicolás

    2004-12-01

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

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

    Science.gov (United States)

    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

  16. Pond dyes are Culex mosquito oviposition attractants

    Directory of Open Access Journals (Sweden)

    Natali Ortiz Perea

    2017-05-01

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

  17. Role of Culex and Anopheles mosquito species as potential vectors of rift valley fever virus in Sudan outbreak, 2007

    Directory of Open Access Journals (Sweden)

    Galal Fatma H

    2010-03-01

    Full Text Available Abstract Background Rift Valley fever (RVF is an acute febrile arthropod-borne viral disease of man and animals caused by a member of the Phlebovirus genus, one of the five genera in the family Bunyaviridae. RVF virus (RVFV is transmitted between animals and human by mosquitoes, particularly those belonging to the Culex, Anopheles and Aedes genera. Methods Experiments were designed during RVF outbreak, 2007 in Sudan to provide an answer about many raised questions about the estimated role of vector in RVFV epidemiology. During this study, adult and immature mosquito species were collected from Khartoum and White Nile states, identified and species abundance was calculated. All samples were frozen individually for further virus detection. Total RNA was extracted from individual insects and RVF virus was detected from Culex, Anopheles and Aedes species using RT-PCR. In addition, data were collected about human cases up to November 24th, 2007 to asses the situation of the disease in affected states. Furthermore, a historical background of the RVF outbreaks was discussed in relation to global climatic anomalies and incriminated vector species. Results A total of 978 mosquitoes, belonging to 3 genera and 7 species, were collected during Sudan outbreak, 2007. Anopheles gambiae arabiensis was the most frequent species (80.7% in White Nile state. Meanwhile, Cx. pipiens complex was the most abundant species (91.2% in Khartoum state. RT-PCR was used and successfully amplified 551 bp within the M segment of the tripartite negative-sense single stranded RNA genome of RVFV. The virus was detected in female, male and larval stages of Culex and Anopheles species. The most affected human age interval was 15-29 years old followed by ≥ 45 years old, 30-44 years old, and then 5-14 years old. Regarding to the profession, housewives followed by farmers, students, shepherd, workers and the free were more vulnerable to the infection. Furthermore, connection between

  18. Role of Culex and Anopheles mosquito species as potential vectors of rift valley fever virus in Sudan outbreak, 2007.

    Science.gov (United States)

    Seufi, Alaaeddeen M; Galal, Fatma H

    2010-03-11

    Rift Valley fever (RVF) is an acute febrile arthropod-borne viral disease of man and animals caused by a member of the Phlebovirus genus, one of the five genera in the family Bunyaviridae. RVF virus (RVFV) is transmitted between animals and human by mosquitoes, particularly those belonging to the Culex, Anopheles and Aedes genera. Experiments were designed during RVF outbreak, 2007 in Sudan to provide an answer about many raised questions about the estimated role of vector in RVFV epidemiology. During this study, adult and immature mosquito species were collected from Khartoum and White Nile states, identified and species abundance was calculated. All samples were frozen individually for further virus detection. Total RNA was extracted from individual insects and RVF virus was detected from Culex, Anopheles and Aedes species using RT-PCR. In addition, data were collected about human cases up to November 24th, 2007 to asses the situation of the disease in affected states. Furthermore, a historical background of the RVF outbreaks was discussed in relation to global climatic anomalies and incriminated vector species. A total of 978 mosquitoes, belonging to 3 genera and 7 species, were collected during Sudan outbreak, 2007. Anopheles gambiae arabiensis was the most frequent species (80.7%) in White Nile state. Meanwhile, Cx. pipiens complex was the most abundant species (91.2%) in Khartoum state. RT-PCR was used and successfully amplified 551 bp within the M segment of the tripartite negative-sense single stranded RNA genome of RVFV. The virus was detected in female, male and larval stages of Culex and Anopheles species. The most affected human age interval was 15-29 years old followed by > or = 45 years old, 30-44 years old, and then 5-14 years old. Regarding to the profession, housewives followed by farmers, students, shepherd, workers and the free were more vulnerable to the infection. Furthermore, connection between human and entomological studies results in

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

    National Research Council Canada - National Science Library

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

    2015-01-01

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

  20. Characterization of an endogenous gene expressed in Aedes aegypti using an orally infectious recombinant sindbis virus

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    L.L. Cheng

    2001-10-01

    Full Text Available Sindbis virus expression vectors have been used successfully to express and silence genes of interest in vivo in several mosquito species, including Aedes aegypti, Ae. albopictus, Ae. triseriatus, Culex pipiens, Armigeres subalbatus and Anopheles gambiae. Here we describe the expression of an endogenous gene, defensin, in Ae. aegypti using the orally infectious Sindbis virus, MRE/3'2J expression vector. We optimized conditions to infect mosquito larvae per os using C6/36 Ae. albopictus cells infected with the recombinant virus to maximize virus infection and expression of defensin. Infection with the parental Sindbis virus (MRE/3'2J did not induce defensin expression. Mosquito larvae infected by ingestion of recombinant Sindbis virus-infected C6/36 cells expressed defensin when they emerged as adults. Defensin expression was observed by western analysis or indirect fluorescent assay in all developmental stages of mosquitoes infected with MRE/3'2J virus that contained the defensin insert. The multiplicity of infection of C6/36 cells and the quantity of infected cells consumed by larvae played an important role in defensin expression. Parental viruses, missing the defensin insert, and/or other defective interfering virus may have contributed to these observations.

  1. Cloning and sequence analysis of β-actin gene from Aedes albopictus (Diptera: Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Weijie Wang; Xiaobang Hu; Donghui Zhang; Jianhua Jiao; Yan Sun; Lei Ma; Changliang Zhu

    2007-01-01

    Objective: To obtain the complete β-actin gene from Aedes albopictus. Methods: Total RNA was extracted from C6/36 cells. Degenerate primers were designed based on the β-actin sequences of An. gambiae, Ae. aegypti, Cx. pipiens pallens and D.melanogaster. By RT-PCR, the product was amplified, purified, cloned into the pGT vector and sequenced. The β-actin sequence was aligned and phylogenetically analyzed by the BLAST program and the CLUSTAL W program. Results: A sequence of 1132 bp including an open reading frame of 1131 bp was obtained (GenBank DQ657949). The deduced protein had 376 amino acids.Aligned to SWISS-PROT, it exhibited a high level of identity with β-actins from Anopheles, Drosophila and Culex at the amino acid sequence level. Phylogenetic analysis indicated that Ae. albopictus β-actin was much more homologous with invertebrate β-actin than with vertebrate β-actin. Conclusion: The gene may be used as the internal control in the experiments of Ae. albopictus.

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

    Science.gov (United States)

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

    2017-10-01

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

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

    Science.gov (United States)

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

    2011-05-01

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

  4. Genomic and evolutionary analyses of Tango transposons in Aedes aegypti, Anopheles gambiae and other mosquito species.

    Science.gov (United States)

    Coy, M R; Tu, Z

    2007-08-01

    Tango is a transposon of the Tc1 family and was originally discovered in the African malaria mosquito, Anopheles gambiae. Here we report a systematic analysis of the genome sequence of the yellow fever mosquito, Aedes aegypti, which uncovered three distinct Tango transposons. We name the only An. gambiae Tango transposon AgTango1 and the three Ae. aegypti Tango elements AeTango1-3. Like AgTango1, AeTango1 and AeTango2 elements both have members that retain characteristics of autonomous elements such as intact open reading frames and terminal inverted repeats (TIRs). AeTango3 is a degenerate transposon with no full-length members. All full-length Tango transposons contain subterminal direct repeats within their TIRs. AgTango1 and AeTango1-3 form a single clade among other Tc1 transposons. Within this clade, AgTango1 and AeTango1 are closely related and share approximately 80% identity at the amino acid level, which exceeds the level of similarity of the majority of host genes in the two species. A survey of Tango in other mosquito species was carried out using degenerate PCR. Tango was isolated and sequenced in all members of the An. gambiae species complex, Aedes albopictus and Ochlerotatus atropalpus. Oc. atropalpus contains a rich diversity of Tango elements, while Tango elements in Ae. albopictus and the An. gambiae species complex all belong to Tango1. No Tango was detected in Culex pipiens quinquefasciatus, Anopheles stephensi, Anopheles dirus, Anopheles farauti or Anopheles albimanus using degenerate PCR. Bioinformatic searches of the Cx. p. quinquefasciatus (~10 x coverage) and An. stephensi (0.33 x coverage) databases also failed to uncover any Tango elements. Although other evolutionary scenarios cannot be ruled out, there are indications that Tango1 underwent horizontal transfer among divergent mosquito species.

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

    Science.gov (United States)

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

    2013-07-01

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

  6. Morphological studies on adult mosquitoes (Diptera: Culicidae) and first report of the potential Zika virus vector Aedes (Stegomyia) unilineatus (Theobald, 1906) in Iran.

    Science.gov (United States)

    Yaghoobi-Ershadi, M R; Doosti, S; Schaffner, F; Moosa-Kazemi, S H; Akbarzadeh, K; Yaghoobi-Ershadi, N

    2017-05-01

    Beside numerous extensive studies on Anophelinae mosquitoes of Iran, little is known on Aedes species in the country and existing reports are dispersed. The objective of this study was to identify adults of Culicinae species occurring in the Sistan and Baluchestan Province, southeast of Iran, during 2012-2014. Mosquito collections were carried out three times (May-June, September, October-November) in four counties by Centers for Diseases Control (CDC) light traps and human landing catches outdoors and under bed nets baited with carbon dioxide. These trapping were carried out two consecutive nights during the field studies. Several mosquito collections were also conducted with aspirator and pyrethrum spray space catches during the day. A total of 1885 mosquitoes were collected, belonging to 10 species of genus Culex including Cx. pipiens Complex, Cx. laticinctus, Cx. sinaiticus, and Cx. tritaeniorhynchus, one species of the genus Culiseta, Cs. longiareolata, and five species of the genus Aedes, Ae. caspius, Ae. vexans, Ae. detritus, Ae. albopictus, and Ae. unilineatus. Ae. vexans was the dominant species in the area (77.7%). During the study, seven Ae. unilineatus were collected in two villages near the city of Chabahar located in a coastal area; this is the first record for Iran and identification was confirmed by Cytochrome oxidase (COI) sequences analysis. Confirmation of the presence of Ae. unilineatus in the country raises the number of species of the genus Aedes to 12. The detection of this species reveals its probable establishment in the southeast of the country, which has implications for public health such as dengue and Zika infections and requires active entomological surveillance and implementation of adapted vector control measures in the area.

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2013-03-01

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

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

    Science.gov (United States)

    Harrington, Laura C; Poulson, Rebecca L

    2008-01-01

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

  10. Identification and Transcription Profiling of NDUFS8 in Aedes taeniorhynchus (Diptera: Culicidae): Developmental Regulation and Environmental Response

    Science.gov (United States)

    2014-12-18

    Laboratory in the Interdisciplinary Center for Biotechnology Research, University of Florida (Gainesville, FL, USA). The DNA sequence was analyzed using...to National Center for Biotechnology Information; GenBank Accession number: FJ458415. Permethrin experiments Five-day old adult female Ae...mitochondrial DNA and infection with symbiotic cytoplasmic bacterium Wolbachia pipientis in mosquitoes of the Culex pipiens complex from Russia

  11. Amostragem por larva-única na vigilância de Aedes aegypti Single-larva sampling for Aedes aegypti surveillance

    Directory of Open Access Journals (Sweden)

    José Eduardo Bracco

    1995-04-01

    Full Text Available Com a finalidade de testar a metodologia de amostragem por larva-única na vigilância entomológica do Aedes aegypti, foram pesquisados domicílios do Município de Araraquara, SP (Brasil. Nos criadouros que continham larvas de Aedes uma delas foi coletada. Como controle, após a coleta da larva-única, todas as larvas foram coletadas para identificação posterior. Esse processo foi repetido no laboratório. Dos 447 domicílios visitados, apenas 12 foram considerados positivos e 20 criadouros foram identificados; destes, 13 continham larvas de Aedes; 5, larvas de Aedes e Culex e 2, larvas de Culex. Os resultados mostram o reconhecimento correto, no campo, de todos os criadouros, evidenciando que o método poderia ser utilizado na vigilância entomológica de municípios sem infestação domiciliar ou infestados apenas com uma única espécie de Aedes.Buildings in Araraquara city, Southeastern Brazil, were searched during a year for the presence of Aedes larvae using single larva sampling in order to check the single-larva methodology. In those breeding places in wich Aedes larvae were found, one of them was collected. As a control, after the single larva had been collected, all the larvae from the breeding place were collected for later identification. This process was repeated in the laboratory. Of the 447 domiciles searched, 12 were considered positive and 20 breeding places were found. Of the breeding places, 13 contained Aedes larvae, 5 both Aedes and Culex larvae and 2 Culex larvae only. The results show that all the breeding places in the field were properly recognited showing the method may be used for Aedes surveillance in cities infested with one species only or without any domiciliary infestation.

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

    Science.gov (United States)

    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.

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

    OpenAIRE

    Carlos Sevilla Andrade; Cáceres,Abraham G; Aldo Vaquerizo; Sergio Ibañez-Bernal; Lourdes Sulca Cachay

    2001-01-01

    We report here the reappearence 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.

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

    Directory of Open Access Journals (Sweden)

    Carlos Sevilla Andrade

    2001-07-01

    Full Text Available We report here the reappearence 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.

  15. Distribution of the members of the Pipiens Assemblage in the sympatric area from Argentina: which is where and when?

    Science.gov (United States)

    Cardo, María V; Rubio, Alejandra; Junges, Melania; Vezzani, Darío; Carbajo, Aníbal E

    2016-01-01

    Given their medical and veterinary relevance, the members of the Pipiens Assemblage are a worldwide target of ecological research. The distribution of Culex pipiens s.s. and Cx. quinquefasciatus converge in Buenos Aires, Argentina, where hybrids have been detected. Each member of the assemblage exhibits a distinct eco-physiological behaviour that can affect its efficiency in pathogen transmission. Our aim was to identify the environmental drivers for the spatio-temporal distribution of each member, focusing on latitudinal and urbanisation gradients. Immatures of mosquitoes were surveyed in artificial containers found within 11 public cemeteries, raised up to the adult stage and identified by their male genitalia. The distribution of each member was associated with the environment in a Generalized Linear Model. The variable accounting for most of the heterogeneity was latitude; Cx. quinquefasciatus was collected more frequently at northern cemeteries, whereas Cx. pipiens and hybrids were more likely at the southern extreme. The urbanisation gradient was also associated with the occurrence of Cx. quinquefasciatus and hybrids at the high and low end, respectively. Other relevant variables were cemetery total area, the proportion with graves and the presence of plastic flowers in the containers. The spatial distribution of the members of the Pipiens Assemblage within the sympatric region in South America is driven by environmental features. The information presented herein provides essential baseline data for surveillance programs and control activities. PMID:27783720

  16. Larvicidal activity and influence of Bacillus thuringiensis var. israelensis on Aedes albopictus oviposition in ovitraps during a two-week check interval protocol.

    Science.gov (United States)

    Carrieri, Marco; Masetti, Antonio; Albieri, Alessandro; Maccagnani, Bettina; Bellini, Romeo

    2009-06-01

    Toxicity persistence of Bacillus thuringiensis var. israelensis (Bti) was evaluated in laboratory and field trials to develop a new protocol for Aedes albopictus monitoring. In the laboratory, the residual toxicity of 5 Bti formulations was compared using the percentage mortality at days 4, 8, 12, and 16 of Culex pipiens larvae exposed for 24 h to Bti treatments. The results showed a good performance of all tested formulations (>97% mortality at day 14, for all the formulations), but only Vectobac 12AS at the concentration of 1 ml/liter showed an efficacy of 100% for 2 wk. A field study was designed to test the effect of Bti on the ovitrap check interval or influence of ovipositional response of gravid Ae. albopictus females. Three different ovitrap treatments were used: ovitraps with tap water checked weekly; ovitraps with tap water checked every 2 wk; ovitraps with Bti (Vectobac 12AS, dose of 1 ml/liter) checked every 2 wk. Our study demonstrated that in the ovitrap, the toxic action of a 1% solution of Bti was maintained for at least 14 days with mortality of 100% and that rainfall did not seem to negatively influence the residual action of Bti. Therefore the probability that the larvae may complete the developmental cycle in ovitraps with Bti seems to be very low. The oviposition activity index showed that Bti enhances the oviposition rate of Ae. albopictus by 17.4%.

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

    Directory of Open Access Journals (Sweden)

    Brittany L. Dodson

    2017-03-01

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

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

    Science.gov (United States)

    Dodson, Brittany L.

    2017-01-01

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

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

    Science.gov (United States)

    Dodson, Brittany L; Rasgon, Jason L

    2017-01-01

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

  20. 氯氰菊酯和残杀威亚致死剂量对致倦库蚊羧酸酯酶活性的影响%Effects of cypermethrin and propoxur at sublethal doses on the carboxylesterase activity in Culex pipiens quinqusfasciatus

    Institute of Scientific and Technical Information of China (English)

    柳小青; 刘仰青; 熊志伟; 马红梅

    2011-01-01

    Objective To determine the changes of carboxylesterase (CarE) activity in Cidex pipiens quinqusfasciatus treated with cypermethrin and propoxur at sublethal doses. Methods The enzyme activities were measured in vitro with an ultraviolet-visible spectrophotometer. Results After 24 h treatment, the enzymatic activity of resistant strains was 1.19 times that of sensitive strains. Significant inhibition was noted in all treatment groups after 48 h. Compared with the 24 h treatment group, the enzymatic activity of the control group, propoxur at LC20, propoxur at LC40, cypermethrin at LC20, and cypermethrin at LC40 decreased by 24.71%, 38.42%, 97.42%, 90.77% and 95.76%, respectively. The decreases in all treated groups were more significant than in the control group. Activities in resistant strains treated with cypermethrin and propoxur at sublethal doses for 48 h were significantly different from the control group, except for the group treated with LC20 propoxur. Compared with the control group, the specific activity was 11.6254 nmol/(mgpro · min) in the group treated with LC40 of propoxur, indicating significant inhibitory effect. In the groups treated with LC20 and LC40 of cypermethrin, the activity was 55.8868 and 54.5530 nmol/ (mgpro · min), respectively, suggesting significant inductive effects. No difference was noted between the two 24 h and 48 h treatment groups. Compared with the 24 h treatment group, the specific activity of the control group, propoxur (at LC20 and LC40) and cypermethrin (at LC40) treated groups decreased by 60.71%, 59.14%, 23.68% and 47.87%, respectively, whereas the cypermethrin LC20 group increased by 23.89%. The decrease in the control group was lower than those in the treatment groups. Conclusion Different levels of carboxylesterase activity were observed in sensitive and resistant Cx. Pipiens quinqusfasciatus when treated with sublethal doses of cypermethrin and propoxur. Thus, indicating their different inhibitory effects and that a

  1. against Spodoptera frugiperda (Lepidoptera: Noctuidae)

    African Journals Online (AJOL)

    STORAGESEVER

    2010-03-01

    Mar 1, 2010 ... Key words: Ricinus communis, Spodoptera frugiperda, insecticidal, insectistatic, castor oil, ricinine. ... (Tinzaara et al., 2006), Culex pipiens, Aedes caspius, .... of the pupae phase duration is termed “developing inhibition” and.

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

    Science.gov (United States)

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

    2006-01-01

    Field and laboratory studies were performed to verify whether Culex theileri Theobald functions as a natural vector of Dirofilaria immitis (Leidy) on Madeira Island, Portugal. CO2-baited light traps (EVS traps) were use to sample mosquitoes monthly basis between February 2002 and February 2003 in the area of Quebradas (Funchal). Three mosquito species were captured, including 58 Culex pipiens L., 790 Cx. theileri, and three Culiseta longiareolata (Macquart). Only C. theileri tested positive for D. immitis. The presence of this filarial worm was detected by direct observation, infectivity assay dissection technique, and polymerase chain reaction methods. Infected mosquitoes were recovered in October and December 2002 and January 2003. These data provide evidence that Cx. theileri could be the main vector of D. immitis in Funchal, Madeira.

  3. [Aedes aegypti and Aedes albopictus in bromeliads grown in the Bauru Municipal Botanical Gardens, São Paulo, Brazil].

    Science.gov (United States)

    Oliveira, Viviane Camila de; Almeida, Luiz Carlos de

    2017-01-23

    The aim of this study was to observe the occurrence of mosquito larvae, especially Aedes aegypti and Aedes albopictus, in the tanks and axillae of bromeliads at the Bauru Municipal Botanical Gardens, São Paulo, Brazil, highlighting the epidemiological implications for the use of these plants. The majority of the larvae belonged to mosquitos from genus Culex, with only occasional findings of A. aegypti and A. albopictus. The use of screens for protection of the plants, exposure to sunlight, and larger amounts of water in the tanks may have influenced the occurrence and grouping of larvae.

  4. Seasonal abundance of Aedes albopictus in selected urban and suburban areas in Penang, Malaysia.

    Science.gov (United States)

    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).

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

    Science.gov (United States)

    Irwin, Patrick; Paskewitz, Susan

    2009-09-01

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

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

    Directory of Open Access Journals (Sweden)

    S Azari-Hamidian

    2007-05-01

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

  7. Effect of Bacillus thuringiensis var.israelensis (Bti) on detoxification enzyme activity of larvae of Culex pipiens pallens and Aedes aegypti%苏云金杆菌以色列亚种对蚊幼虫体内解毒酶活性的影响

    Institute of Scientific and Technical Information of China (English)

    韩光杰; 李传明; 孙俊; 刘琴; 赵松; 祁建杭; 徐健

    2015-01-01

    目的 研究苏云金杆菌以色列亚种(Bacillus thuringrensis var.israelesis,Bti)对蚊幼虫体内3种解毒酶活性的影响.方法 采用室内生物测定的方法,分别测定淡色库蚊和埃及伊蚊幼虫取食Bti后体内谷胱甘肽转移酶、乙酰胆碱酯酶和羧酸酯酶的活性.结果 Bti对蚊幼虫体内3种解毒酶活性均产生影响.蚊幼虫在Bti处理后谷胱甘肽转移酶活性显著增强又迅速下降、后期持续抑制;羧酸酯酶活性上升后迅速下降并恢复到正常水平;乙酰胆碱酯酶活性受Bti影响较小,前期受到抑制后逐步回升至正常水平.3种酶活性与Bti浓度呈正相关.结论 Bti可显著影响蚊幼体内谷胱甘肽转移酶、乙酰胆碱酯酶和羧酸酯酶的活性.

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

    Directory of Open Access Journals (Sweden)

    Rebekah J Kent

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

  9. Winter biology of Culex pipiens quinquefasciatus say, (Diptera: Culicidae from Córdoba, Argentina

    Directory of Open Access Journals (Sweden)

    Walter R Almirón

    1996-10-01

    Full Text Available Adult cohorts and immature stages were kept under field conditions during the autumn and winter of three consecutive years. Survival, oviposition and development time from egg to adult were considered. The adult cohorts were studied under three experimental conditions: unfed cohorts, cohorts fed with sugar solution ansd cohorts fed with both sugar solution and blood (chicken. Female longevity showed significant differences among the three treatments. Females of unfed cohorts lived up to three weeks; females fed with sugar solution survived until six weeks, while those fed both with sugar and blood lived at most fourteen weeks; after the blood intake eggs were laid. In the immature stages, the highest relative mortality rates occurred during the egg and larval stages. Total pre-adult mortality varied between 59.09 and 89.71%. The developmental duration from egg to adult was between 43-62 days; there were no differences among results obtained for the three years.

  10. The vortex wake of the free-swimming larva and pupa of Culex pipiens (Diptera).

    Science.gov (United States)

    Brackenbury, J

    2001-06-01

    The kinematics and hydrodynamics of free-swimming pupal and larval (final-instar) culicids were investigated using videography and a simple wake-visualisation technique (dyes). In both cases, swimming is based on a technique of high-amplitude, side-to-side (larva) or up-and-down (pupa) bending of the body. The pupa possesses a pair of plate-like abdominal paddles; the larval abdominal paddle consists of a fan of closely spaced bristles which, at the Reynolds numbers involved, behaves like a continuous surface. Wake visualisation showed that each half-stroke of the swimming cycle produces a discrete ring vortex that is convected away from the body. Consecutive vortices are produced first to one side then to the other of the mean swimming path, the convection axis being inclined at approximately 25 degrees away from dead aft. Pupal and larval culicids therefore resemble fish in using the momentum injected into the water to generate thrust. Preliminary calculations for the pupa suggest that each vortex contains sufficient momentum to account for that added to the body with each half-stroke. The possibility is discussed that the side-to-side flexural technique may allow an interaction between body and tail flows in the production of vorticity.

  11. Natural vertical transmission of Ndumu virus in Culex pipiens (Diptera; Culicidae) mosquitoes collected as larvae

    Science.gov (United States)

    Ndumu virus (NDUV) is a member of the Family: Togaviridae and Genus: Alphavirus. In Kenya the virus has been isolated from a range of mosquito species but has not been associated with human or animal morbidity. Little is know about the transmission dynamics or vertebrate reservoirs of this virus. We...

  12. Sound and vibration sensitivity of VIIIth nerve fibers in the frogs Leptodactylus albilabris and Rana pipiens pipiens

    DEFF Research Database (Denmark)

    Christensen-Dalsgaard, J; Narins, P M

    1993-01-01

    1. Responses of 73 fibers to dorso-ventral vibration were recorded in the saccular and utricular branchlets of Rana pipiens pipiens using a ventral approach. The saccular branchlet contained nearly exclusively vibration-sensitive fibers (33 out of 36) with best frequencies (BFs) between 10 and 70...

  13. Enhancement of Cry19Aa Mosquitocidal Activity against Aedes aegypti by Mutations in the Putative Loop Regions of Domain II

    OpenAIRE

    Abdullah, Mohd Amir F.; Donald H Dean

    2004-01-01

    Improvements in the mosquitocidal activity of Bacillus thuringiensis Cry19Aa were achieved by protein engineering of putative surface loop residues in domain II through rational design. The improvement of Aedes toxicity in Cry19Aa was 42,000-fold and did not affect its toxicity against Anopheles or Culex.

  14. Efficacy of the vegetative cells of Lysinibacillus sphaericus for biological control of insecticide-resistant Aedes aegypti

    National Research Council Canada - National Science Library

    Paula Andrea Rojas-Pinzon; Jenny Dussan

    2017-01-01

    ... such as Culex spp., Anopheles spp. and Aedes spp., and thus, an endemic country for the diseases transmitted by these mosquitoes [2]. Since the re-invasion of Ae. aegypti in the 1960s, prevention against the diseases transmitted by this mosquito is based on the use of chemical insecticides [5]. Although biological control of Ae. aeg...

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

    Science.gov (United States)

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

    2007-01-01

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

  16. Oviposition ecology and species composition of Aedes spp. and Aedes aegypti dynamics in variously urbanized settings in arbovirus foci in southeastern Côte d'Ivoire.

    Science.gov (United States)

    Zahouli, Julien B Z; Utzinger, Jürg; Adja, Maurice A; Müller, Pie; Malone, David; Tano, Yao; Koudou, Benjamin G

    2016-09-29

    Aedes mosquito-transmitted outbreaks of dengue and yellow fever have been reported from rural and urban parts of Côte d'Ivoire. The present study aimed at assessing Aedes spp. oviposition ecology in variously urbanized settings within arbovirus foci in southeastern Côte d'Ivoire. Aedes spp. eggs were sampled using a standard ovitrap method from January 2013 to April 2014 in different ecosystems of rural, suburban and urban areas. Emerged larvae were reared until the adult stage for species identification. Aedes spp. oviposition ecology significantly varied from rural-to-urban areas and according to the ecozones and the seasons. Species richness of Aedes spp. gradually decreased from rural (eight species) to suburban (three species) and urban (one species) areas. Conversely, emerged adult Aedes spp. mean numbers were higher in the urban (1.97 Aedes/ovitrap/week), followed by the suburban (1.44 Aedes/ovitrap/week) and rural (0.89 Aedes/ovitrap/week) areas. Aedes aegypti was the only species in the urban setting (100 %), and was also the predominant species in suburban (85.5 %) and rural (63.3 %) areas. The highest Ae. aegypti mean number was observed in the urban (1.97 Ae. aegypti/ovitrap/week), followed by the suburban (1.20 Ae. aegypti/ovitrap/week) and rural (0.57 Ae. aegypti/ovitrap/week) areas. Aedes africanus (9.4 %), Ae. dendrophilus (8.0 %), Ae. metallicus (1.3 %) in the rural, and Ae. vittatus (6.5 %) and Ae. metallicus (1.2 %) in the suburban areas each represented more than 1 % of the total Aedes fauna. In all areas, Aedes species richness and abundance were higher in the peridomestic zones and during the rainy season, with stronger variations in species richness in the rural and in abundance in the urban areas. Besides, the highest Culex quinquefasciatus abundance was found in the urban areas, while Eretmapodites chrysogaster was restricted to the rural areas. Urbanization correlates with a substantially higher abundance in Aedes mosquitoes and

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

    Science.gov (United States)

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

    2010-12-01

    The role of lactic acid was evaluated for attraction of Culex nigripalpus, Culex quinquefasciatus, Culex tarsalis, and Aedes aegypti in the laboratory using a dual-port olfactometer. When lactic acid was combined with chicken odor, attraction was increased for Cx. quinquefasciatus compared to chicken odor alone but not for Cx. nigripalpus, Cx. tarsalis, and Ae. aegypti. Lactic acid combined with hand odor did not change attraction of Cx. tarsalis and Ae. aegypti but decreased attraction of Cx. nigripalpus and Cx. quinquefasciatus. The addition of lactic acid to CO(2) increased attraction of Ae. aegypti and Cx. quinquefasciatus but reduced attraction of Cx. nigripalpus and Cx. tarsalis. Use of commercial lactic acid baits with CO(2) resulted in a similar trend except for Cx. nigripalpus which showed no difference. A blend of lactic acid, acetone, and dimethyl disulfide was attractive to Ae. aegypti (63.4%) but elicited low responses by all Culex spp. (1.3-26.8%). Addition of the blend to CO(2) increased attraction of Ae. aegypti and Cx. quinquefasciatus but reduced attraction of Cx. nigripalpus and Cx. tarsalis. The mixture of compounds plus CO(2) was as attractive as a hand for Cx. quinquefasciatus, Cx. tarsalis, and Ae. aegypti.

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

    Science.gov (United States)

    Darsie, Richard F; Day, Jonathan F

    2006-09-01

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

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

    Science.gov (United States)

    Darsie, Richard F; Shroyer, Donald A

    2004-09-01

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

  20. The salivary purine nucleosidase of the mosquito, Aedes aegypti.

    Science.gov (United States)

    Ribeiro, José M C; Valenzuela, Jesus G

    2003-01-01

    A cDNA clone originating from adult female Aedes aegypti mosquitoes was found with substantial similarity to nucleosidases of the EC 3.2.2.1 enzyme class. Although this type of enzyme is unusual in animals, abundant enzyme activity was found in salivary homogenates of this mosquito, but not in salivary homogenates of the mosquitoes Anopheles gambiae and Culex quinquefasciatus, or the sand fly Lutzomyia longipalpis. Aedes salivary homogenate hydrolyses inosine and guanosine to hypoxanthine and xanthine plus the ribose moiety, but does not hydrolyse the pyrimidines uridine and cytidine, thus characterizing the presence of a purine nucleosidase activity. The enzyme is present in oil-induced saliva, indicating that it is secreted. Male Ae. aegypti salivary gland homogenates (SGH) have very low purine nucleosidase activity, suggesting that the enzyme plays a role in mosquito blood feeding. A novel isocratic HPLC method to separate nucleosides and their bases is described.

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

    Science.gov (United States)

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

    2009-11-01

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

  2. Evaluation of bifenthrin applications in tires to prevent Aedes mosquito breeding.

    Science.gov (United States)

    Nguyen, Huy T; Whelan, Peter I; Shortus, Matthew S; Jacups, Susan P

    2009-03-01

    The efficacy of maximum label rates of bifenthrin applications to dry tires to prevent Aedes mosquito breeding was investigated by field colonization and bioassay trials in shaded and unshaded locations. Aedes notoscriptus and Culex quinquefasciatus larvae were the most abundant species present in the field colonization trial. Colonization and survival of Ae. notoscriptus larvae to the late instar occurred significantly earlier in treated tires in shaded compared with unshaded locations (P = 0.002). Bifenthrin applications in shaded tires only prevented early instar survival for approximately 2.6 wk. Aedes notoscriptus late instars did not appear in the treated unshaded tires. Culex quinquefasciatus colonized treated tires from the 2nd wk in both shaded and unshaded treatments. In the bioassay, water from bifenthrin-treated tires, through extrapolation, was found to kill approximately 100% of late instar Ae. notoscriptus for only approximately 2.0-2.2 wk in shaded and unshaded tires. Under conditions optimal for Aedes breeding, such as shaded locations, high ambient temperatures, high relative humidity, and high amounts of leaf/organic matter accumulations, bifenthrin may not be effective as a larval control measure in tires for greater than 2.0-2.6 wk.

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

    OpenAIRE

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

    2011-01-01

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

  4. Wolbachia strain wPip yields a pattern of cytoplasmic incompatibility enhancing a Wolbachia-based suppression strategy against the disease vector Aedes albopictus

    Directory of Open Access Journals (Sweden)

    Calvitti Maurizio

    2012-11-01

    Full Text Available Abstract Background Cytoplasmic incompatibility (CI is induced in nature by Wolbachia bacteria, resulting in conditional male sterility. Previous research demonstrated that the two Wolbachia strains (wAlbA and wAlbB that naturally co-infect the disease vector mosquito Aedes albopictus (Asian tiger mosquito can be replaced with the wPip Wolbachia strain from Culex pipiens. Since Wolbachia-based vector control strategies depend upon the strength and consistency of CI, a greater understanding is needed on the CI relationships between wPip, wAlbA and wAlbB Wolbachia in Ae. albopictus. Methods This work consisted of a collaborative series of crosses carried out in Italy and in US to study the CI relationships between the “wPip” infected Ae. albopictus strain (ARwP and the superinfected SR strain. The Ae. albopictus strains used in Italian tests are the wPip infected ARwP strain (ARwPIT, the superinfected SR strain and the aposymbiotic AR strain. To understand the observed pattern of CI, crossing experiments carried out in USA focused on the study of the CI relationships between ARwP (ARwPUS and artificially-generated single infected lines, in specific HTA and HTB, harbouring only wAlbA and wAlbB Wolbachia respectively. Results The paper reports an unusual pattern of CI observed in crossing experiments between ARwP and SR lines. Specifically, ARwP males are able to induce full sterility in wild type females throughout most of their lifetime, while crosses between SR males and ARwP females become partially fertile with male aging. We demonstrated that the observed decrease in CI penetrance with SR male age, is related to the previously described decrease in Wolbachia density, in particular of the wAlbA strain, occurring in aged superinfected males. Conclusions The results here reported support the use of the ARwP Ae. albopictus line as source of “ready-made sterile males”, as an alternative to gamma radiation sterilized males, for autocidal

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

    Science.gov (United States)

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

    2009-03-01

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

  6. Efficacy of alpha-cypermethrin and lambda-cyhalothrin applications to prevent Aedes breeding in tires.

    Science.gov (United States)

    Pettit, William J; Whelan, Peter I; McDonnell, Joseph; Jacups, Susan P

    2010-12-01

    The efficacy of alpha-cypermethrin (Cyperthor) and lambda-cyhalothrin (Demand) to prevent mosquito larval colonization of water-containing receptacles was investigated using 2 differing applications in disused car tires in Darwin, Australia. Insecticide treatments were applied uniformly to the inside surfaces of 2 categories of tires: 1) dry tires that were partially filled with water 24 h after spraying and 2) wet tires partially filled with water prior to spraying. All mosquito larvae, pupae, and dead adults were collected from the treatment and control tires weekly over the 24-wk study period and were later identified to species in the laboratory. Control tires were colonized by Aedes notoscriptus in wk 2 and by Culex quinquefasciatus in wk 4. Aedes notoscriptus failed to colonize any alpha-cypermethrin-treated tires until wk 22 and did not colonize any lambda-cyhalothrin-treated tires during the 24-wk trial. Culex quinquefasciatus colonized alpha-cypermethrin and lambda-cyhalothrin-treated tires from wk 11 and wk 15, respectively. These results indicate both insecticides using either application method can prevent colonization of Ae. notoscriptus for at least 20 wk and demonstrate great potential for the prevention of breeding in receptacles for other receptacle-breeding Aedes species, such as the dengue vectors, Ae. aegypti and Ae. albopictus.

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

    National Research Council Canada - National Science Library

    João A. C. Zequi; José Lopes

    2007-01-01

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

  8. Mitotic activity in dorsal epidermis of Rana pipiens.

    Science.gov (United States)

    Garcia-Arce, H.; Mizell, S.

    1972-01-01

    Study of statistically significant rhythms of mitotic division in dorsal epidermis of frogs, Rana pipiens, exposed to a 12:12 light:dark environment for 14 days. The results include the findings that (1) male animals have a primary period of 22 hr in summer and 18 hr in winter, (2) female animals have an 18 hr period, and (3) parapinealectomy and blinding abolish the rhythm.

  9. Principales criaderos para Aedes aegypti y culícidos asociados, Argentina Main breeding-containers for Aedes aegypti and associated culicids, Argentina

    Directory of Open Access Journals (Sweden)

    Marina Stein

    2002-10-01

    Full Text Available Se identificaron criaderos de Aedes (Stegomyia aegypti en dos ciudades de la provincia del Chaco (Noreste de Argentina: Presidencia Roque Saenz Peña y Machagai. Los recipientes encontrados en los patios de las viviendas capaces de colectar agua se clasificaron según tipo y tamaño, se contaron y examinaron. Aedes aegypti y Culex quinquefasciatus fueron las especies mas abundantes, encontrándose además Cx. maxi, Cx. saltanensis y Ochlerotatus scapularis. Los neumáticos y cajas de baterías para autos fueron los recipientes que más aportaron a la producción de formas inmaduras de los culícidos colectados. Las lluvias fueron un factor importante para la proliferacion de Ae. aegypti, así como también el habito comun en la población de guardar recipientes en sus casas que permitan el desarrollo de estos culícidos.Breeding containers for Aedes (Stegomyia aegypti were identified in two cities of Chaco Province (northeast Argentina: Presidencia Roque Saenz Peña and Machagai. All water-retaining recipients found in house backyards capable to retain water were classified according to their type and size, counted and checked. Aedes aegypti and Culex quinquefasciatus were the most frequently collected species, being also found Cx. maxi, Cx. saltanensis and Ochlerotatus scapularis. Tires and car batteries represented the most important type of container where immature forms of culicids could be found. Rain was an important factor for Ae. aegypti proliferation, as well as the widespread habit of the population of keeping useless containers at home, which allows the development of culicids.

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

    Directory of Open Access Journals (Sweden)

    Rosilainy Surubi Fernandes

    2016-09-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2007-05-01

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

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

    Science.gov (United States)

    Darsie, Richard F; Day, Jonathan F

    2004-06-01

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

  14. Aedes albopictus (Skuse en la Región Huetar Atlántica de Costa Rica

    Directory of Open Access Journals (Sweden)

    Olger Calderón Arguedas

    2012-12-01

    Full Text Available Objetivo: Determinar las características de los hábitats larvales de Ae. albopictus y su culicidofauna asociada en la comunidad “La Primavera”. Métodos: Se realizó una encuesta larval en 20 de 28 casas ubicadas en un área de 10 000 m², en la cual se evaluaron los entornos intra y peridomiciliares para la ubicación de posibles criaderos de mosquitos. El material entomológico se fijó en etanol al 70 % y se procesó para su análisis por microscopía de luz. Resultados: En 15 viviendas los criaderos de mosquitos resultaron positivos. En dichas viviendas se encontraron 48 criaderos, de los cuales 31,2 % estuvieron positivos por larvas o pupas de mosquitos. Se encontró Aedes albopictus en cinco criaderos en coexistencia con otras especies como Culex coronator, Haemagogus regalis y Limatus durhamii. También fueron observados Culex quinquefasciatus, Culex corniger, Culex interrogator, Trichoprosopon compressum y Aedes motoecopus. No se observó Aedes aegypti en la muestra. Discusión: Los resultados preliminares muestran que Ae. albopictus tiene gran afinidad por compartir el hábitat con otros culícidos en entornos rurales y semi-rurales, donde los criaderos se encuentran preferencialmente en el peridomicilio. La ausencia de Ae. aegypti podría reflejar algún grado de exclusión competitiva que genera Ae. albopictus sobre esta última. Queda pendiente determinar el papel que podría jugar Ae. albopictus en la transmisión local del dengue en la región.

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

    Science.gov (United States)

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

    2013-01-01

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

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

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    Olson Kenneth E

    2010-01-01

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

  17. Trisomy in Aedes aegypti

    Energy Technology Data Exchange (ETDEWEB)

    Ved Brat, S.; Rai, K.S.

    1975-01-01

    A trisomic (2n = 6 + 1) pupa of the yellow fever mosquito Aedes aegypti has been found. The trisomy involved chromosome 3 which is intermediate in size between 1 and 2. The extra chromosome formed a univalent or a trivalent during meiosis.

  18. IDENTIFIKASI AEDES AEGYPTI DAN AEDES ALBOPICTUS

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    Diah Fitri Rahayu

    2013-09-01

    Full Text Available ABSTRAK. Demam Berdarah Dengue (DBD adalah penyakit yang disebabkan oleh virus Dengue yangditularkan oleh nyamuk . Kabupaten Banjarnegara merupakan daerah endemis reseptif DBD. Dari tahun ketahun kasus DBD cenderung meningkat, terutama di tahun 2009 - 2010. Vektor DBD di Kabupaten Banjarnegaraadalah Ae. aegypti dan Ae. albopictus. Ae. aegypti secara makroskopis terlihat sama seperti Ae. albopictus,namun perbedaannya terletak pada morfologi kepala (mesonotum di mana Ae. aegypti memiliki gambar garisseperti kepala kecapi berbentuk dengan dua garis lengkung dan dua garis lurus putih sementara Ae. albopictushanya memiliki satu garis putih di mesonotum tersebut.Kata kunci: identifikasi, Ae. aegypti, Ae. albopictusABSTRACT. Dengue hemorrhagic fever (DHF is a disease caused by the dengue virus transmitted by mosquito.Banjarnegara district is a Dengue receptive endemic area. From year to year the Dengue cases is likely toincrease, especially in 2009 - 2010. The main vector of dengue in Banjarnegara district is Aedes aegypti andAedes albopictus. Ae. aegypti morphologically look like with Ae. albopictus, but the difference lies in the headmorphology (mesonotum where A. aegypti has a picture of the line like a lyre-shaped head with two curved linesand two white straight line while A. albopictus has only one white stripe on the mesonotum.Key words:identification, Ae. aegypti, Ae. albopictus

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

    Science.gov (United States)

    Emerson, Kevin J; Glaser, Robert L

    2017-08-07

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

  20. The effects of climate change and globalization on mosquito vectors: evidence from Jeju Island, South Korea on the potential for Asian tiger mosquito (Aedes albopictus influxes and survival from Vietnam rather than Japan.

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    Su Hyun Lee

    Full Text Available BACKGROUND: Climate change affects the survival and transmission of arthropod vectors as well as the development rates of vector-borne pathogens. Increased international travel is also an important factor in the spread of vector-borne diseases (VBDs such as dengue, West Nile, yellow fever, chikungunya, and malaria. Dengue is the most important vector-borne viral disease. An estimated 2.5 billion people are at risk of infection in the world and there are approximately 50 million dengue infections and an estimated 500,000 individuals are hospitalized with dengue haemorrhagic fever annually. The Asian tiger mosquito (Aedes albopictus is one of the vectors of dengue virus, and populations already exist on Jeju Island, South Korea. Currently, colder winter temperatures kill off Asian tiger mosquito populations and there is no evidence of the mosquitos being vectors for the dengue virus in this location. However, dengue virus-bearing mosquito vectors can inflow to Jeju Island from endemic area such as Vietnam by increased international travel, and this mosquito vector's survival during colder winter months will likely occur due to the effects of climate change. METHODS AND RESULTS: In this section, we show the geographical distribution of medically important mosquito vectors such as Ae. albopictus, a vector of both dengue and chikungunya viruses; Culex pipiens, a vector of West Nile virus; and Anopheles sinensis, a vector of Plasmodium vivax, within Jeju Island, South Korea. We found a significant association between the mean temperature, amount of precipitation, and density of mosquitoes. The phylogenetic analyses show that an Ae. albopictus, collected in southern area of Jeju Island, was identical to specimens found in Ho Chi Minh, Vietnam, and not Nagasaki, Japan. CONCLUSION: Our results suggest that mosquito vectors or virus-bearing vectors can transmit from epidemic regions of Southeast Asia to Jeju Island and can survive during colder winter

  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?

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    Márcio Goulart Mocellin

    2009-12-01

    Full Text Available 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.

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

    Science.gov (United States)

    Darsie, Richard F; Day, Jonathan F

    2005-06-01

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

  3. Role of the repartition of wetland breeding sites on the spatial distribution of Anopheles and Culex, human disease vectors in Southern France

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    Fontenille Didier

    2011-05-01

    Full Text Available Abstract Background In this study, carried out in the Camargue region (France, we combined entomological data with geomatic and modelling tools to assess whether the location of breeding sites may explain the spatial distribution of adult mosquitoes. The species studied are important and competent disease vectors in Europe: Culex modestus Ficalbi and Cx. pipiens Linnaeus (West Nile virus, Anopheles atroparvus Van Thiel, a former Plasmodium vector, and An. melanoon Hackett, competent to transmit Plasmodium. Using a logistic regression model, we first evaluated which land cover variables determined the presence of Culex and Anopheles larva. The resulting probability map of larval presence then was used to project the average probability of finding adults in a buffer area. This was compared to the actual number of adults collected, providing a quantitative assessment of adult dispersal ability for each species. Results The distribution of Cx. modestus and An. melanoon is mainly driven by the repartition of irrigated farm fields and reed beds, their specific breeding habitats. The presence of breeding sites explained the distribution of adults of both species. The buffer size, reflecting the adult dispersal ability, was 700 m for Cx. modestus and 1000 m for An. melanoon. The comparatively stronger correlation observed for Cx. modestus suggested that other factors may affect the distribution of adult An. melanoon. We did not find any association between Cx. pipiens larval presence and the biotope due to the species' ubiquist character. Conclusion By applying the same method to different species, we highlighted different strengths of association between land cover (irrigated farm fields and reed beds, larval presence and adult population distribution. This paper demonstrates the power of geomatic tools to quantify the spatial organization of mosquito populations, and allows a better understanding of links between landcover, breeding habitats, presence

  4. Microevolution of Aedes aegypti

    OpenAIRE

    Caroline Louise; Paloma Oliveira Vidal; Lincoln Suesdek

    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 va...

  5. Acid exposure is an immune disruptor in adult Rana pipiens.

    Science.gov (United States)

    Vatnick, Itzick; Andrews, Jaime; Colombo, Matthew; Madhoun, Hareth; Rameswaran, Muthuramanan; Brodkin, Marc A

    2006-01-01

    Acidic environments are physiological stressors for amphibians. The objective of the present study was to document the effect of an acidic environment on innate immune system function under controlled experimental conditions in Rana pipiens. We developed an in vivo assay, by injecting a suspension of 1-microm fluorescent beads in fluid thioglycollate, to induce peritonitis. The number of peritoneal exudate leukocytes and their phagocytic activity did not increase with thioglycollate injection when frogs were exposed to pH 5.5 compared to when frogs were exposed to pH 7.0. An environment of pH 5.5 disrupted the inflammatory response of frogs compared to an environment of pH 7.0; at pH 5.5, more nonphagocytic leukocytes and fewer highly phagocytic leukocytes were found compared to those in frogs exposed to pH 7.0. Frogs stimulated by thioglycollate injection and exposed to pH 5.5 had a 50% increase in cells that did not exhibit phagocytosis and a 4- to 10-fold reduction in the number of highly phagocytic cells. This is evidence that acid exposure functions as an immune disruptor in adult R. pipiens under laboratory conditions.

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

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    João Antonio C. Zequi

    2012-03-01

    Full Text Available Development of the immature stages of Culex (Culex saltanensis Dyar (Diptera, Culicidae under laboratory conditions. Culex (Culex saltanensis Dyar, 1928 is becoming frequent and abundant in natural and artificial breeding sites in urban and rural areas of Brazil. This study contributes to the knowledge of the biology of a Brazilian strain of C. saltanensis. The development of specimens reared individually or grouped was observed. The study was conducted at a constant temperature of 27 ± 2°C, 14L:10D photoperiod and 80 ± 5% relative humidity. The immature stages were observed every 6 hours until adult emergence, which occurred in 12.29 days among individually reared specimens and in 13.12 days among group-reared specimens. Egg rafts for the experiment were obtained from the laboratory and field. Eggs hatched at a rate of 97.48 ± 2.32%. More eggs per egg raft were obtained from the field than from the laboratory. Males from individually reared specimens emerged in 12.29 ± 1.11 days and females in 13.12 ± 1.58 days. The male-female ratio was 1:1. Larval survival rate was higher than 85% for larvae reared isolated and higher than 95% for group-reared larvae. The Culex saltanensis life cycle was completed within 12 to 14 days, where larval instars I and IV took the most time to develop and the pupae, the shortest.

  7. Ecological Niche Modeling of Potential West Nile Virus Vector Mosquito Species in Iowa

    OpenAIRE

    2010-01-01

    Ecological niche modeling (ENM) algorithms, Maximum Entropy Species Distribution Modeling (Maxent) and Genetic Algorithm for Rule-set Prediction (GARP), were used to develop models in Iowa for three species of mosquito — two significant, extant West Nile virus (WNV) vectors (Culex pipiens L and Culex tarsalis Coquillett (Diptera: Culicidae)), and the nuisance mosquito, Aedes vexans Meigen (Diptera: Culicidae), a potential WNV bridge vector. Occurrence data for the three mosquito species from ...

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

    Science.gov (United States)

    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

  9. The Developmental Effects Of A Municipal Wastewater Effluent On The Northern Leopard Frog, Rana pipiens

    Science.gov (United States)

    Wastewater effluents are complex mixtures containing a variety of anthropogenic compounds, many of which are known endocrine disruptors. In order to characterize the development and behavorial effects of such a complex mixture, northern leopard frogs, Rana pipiens, were e...

  10. Species composition and population dynamics of Aedes mosquitoes, potential vectors of arboviruses, at the container terminal of the autonomous port of Abidjan, Côte d’Ivoire

    Science.gov (United States)

    Konan, Yao Lucien; Coulibaly, Zanakoungo Ibrahim; Koné, Atiuomounan Blaise; Ekra, Kouadio Daniel; Doannio, Julien Marie-Christian; Dosso, Mirielle; Odéhouri-Koudou, Paul

    2013-01-01

    An entomological survey of Aedes mosquitoes was initiated at the container terminal of the Autonomous Port of Abidjan in 2009 following the occurrence of two outbreaks of yellow fever in less than 10 years and dengue cases reported in 2008 among expatriates returning from Côte d’Ivoire (Ivory Coast). It was based on regular monitoring of ovitraps from July 2009 to June 2010. A total of 4,739 adult mosquitoes represented by four species of Aedes (97% of total) and one unexpected species of Culex (3%) were obtained. Aedes aegypti was dominant with 98% of total Aedes (n = 4,594). Its density variation was closely related to the amount of rainfall. The other species of Aedes were collected in the second half of the major rainy season including Ae. albopictus (1.17% of Aedes) and Ae. angustus (0.13%) whose presence was discovered for the first time in Côte d’Ivoire. PMID:23567057

  11. Movement of Aedes aegypti following a sugar meal and its implication in the development of control strategies in Durán, Ecuador.

    Science.gov (United States)

    Qualls, Whitney A; Naranjo, Diana P; Subía, Miguel Angel; Ramon, Giovanni; Cevallos, Varsovia; Grijalva, Isabel; Gómez, Eduardo; Arheart, Kristopher L; Fuller, Douglas O; Beier, John C

    2016-12-01

    We evaluated how the presence of sugar sources impacted the distribution of Aedes aegypti in different habitats in Durán, Ecuador. Land cover and normalized difference vegetation index maps were used to guide a random point sampling routine to select study grids (30 m × 30 m) in low vegetation (LV) and high vegetation (HV). Five individual plants, at one home in the LV and HV grid, were treated with a different colored, non-attractive, 60% sucrose solution to determine mosquito feeding and movement. Sugar alone is not attractive to mosquitoes, so spraying vegetation with a dyed sugar solution can be used for visual determination of sugar feeding. Outdoor collections using BG sentinel traps and indoor collections using aspirators were conducted at the treatment home and with collection points at 20, 40, and 60 m surrounding the treatment home for three consecutive days. A total of 3,245 mosquitoes in two genera, Aedes and Culex, was collected. The proportion of stained Ae. aegypti females was 56.8% (510/898) and 0% for males. For Culex, 63.9% (248/388) females and 36.1% (140/388) males were collected stained. Aedes aegypti and Culex spp. were found up to 60 m stained in both LV and HV grids. Significantly more stained females Ae. aegypti were found inside homes compared to females and males of Culex spp. in both habitats. This study identifies that outdoor sugar feeding is a common behavior of Ae. aegypti and can be targeted as a control strategy in urban habitats in Latin America.

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

    Science.gov (United States)

    Darsie, Richard F; Day, Jonathan F

    2007-06-01

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

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

    Science.gov (United States)

    Mulla, Mir S; Thavara, Usavadee; Tawatsin, Apiwat; Chomposri, Jakkrawarn; Su, Tianyun

    2003-03-01

    In recent years, highly potent mosquitocidal strains of the microbial agent Bacillus sphaericus (Bsph) have been isolated and developed for the control of mosquito larvae around the world. Laboratory selection experiments with the most active strains and their use in large-scale operational mosquito control programs resulted in the emergence of resistance in larvae of the Culex pipiens complex. This generated great concern among vector control agencies around the world, who feared reduced efficacy of this highly active larvicidal agent. To address this issue, the current studies were started to find practical strategies for controlling resistant mosquitoes and more importantly to develop resistance management strategies that would prevent or delay development of resistance. We initiated field studies in 3 low-income communities in Nonthaburi Province, Thailand. In 1 of the communities, larvae of Culex quinquefasciatus that were highly resistant (>125,000-fold) to Bsph strain 2362 were successfully controlled with applications of Bacillus thuringiensis var. israelensis (Bti) alone or in combination with Bsph. To prevent or delay resistance to Bsph, 2 other sites were selected, 1 treated with Bsph 2362 alone and the other treated with a mixture of Bsph 2362 and Bti. Mosquitoes treated with Bsph 2362 alone showed some resistance by the 9th treatment and almost complete failure of control occurred by the 17th treatment. After 9 treatments with the mixture over a 9-month period at another site, no noticeable change in susceptibility to Bsph was detected. During this period, the site treated with Bsph alone required 19 treatments, whereas the site treated with mixtures took only 9 treatments because of slower resurgence of larvae at the site treated with the mixture than at the site treated with Bsph alone. This is the 1st field evidence for delay or prevention of resistance to microbial agents in larval Cx. quinquefasciatus by using mixtures of Bti and Bsph. Further

  14. Comparative Efficiency of Biogents Gravid Aedes Trap, Cdc Autocidal Gravid Ovitrap, and CDC Gravid Trap in Northeastern Florida.

    Science.gov (United States)

    Cilek, James E; Knapp, Jennifer A; Richardson, Alec G

    2017-06-01

    We conducted a study to compare the effectiveness of the Biogents Gravid Aedes Trap (BG-GAT) and Centers for Disease Control and Prevention (CDC) Autocidal Gravid Ovitrap (AGO) with that of the CDC Gravid Trap (CDC-GT) (as a standard) for their proficiency to collect mosquitoes in an urban residential neighborhood in northeastern Florida. Aedes aegypti , Ae. albopictus, and Culex quinquefasciatus were collected from each trap, with the latter species being predominant. Significantly more Cx. quinquefasciatus were collected from CDC-GT traps compared with the other 2 traps. Pairwise comparison of the efficiency of the CDC-GT revealed that this trap collected 6.7- to 21.5-fold more mosquitoes than the BG-GAT, depending on species. The BG-GAT collected overall more mosquitoes (3- to 6-fold) than the AGO, with the exception of Ae. aegypti, where both traps were nearly equal in effectiveness.

  15. ANCAMAN DARI NYAMUK Culex sp YANG TERABAIKAN

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    Zumrotus Sholichah

    2012-11-01

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

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

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    Julia Knöckel

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

  17. Pathogenicity Tests on Nine Mosquito Species and Several Non-target Organisms with Strelkovimermis spiculatus (Nemata Mermithidae).

    Science.gov (United States)

    Becnel, J J; Johnson, M A

    1998-12-01

    Nine species of mosquitoes and several species of non-target aquatic organisms were tested for susceptibility to the mernaithid nematode, Strelkovimermis spiculatus. All species of Anopheles, Aedes, Culex, and Toxorhynchites exposed to S. spiculatus were susceptible. Of the nine mosquito species tested, C. pipiens quinquefasciatus had the greatest tolerance to initial invasion and the highest percent infection of those that survived. High levels of infection were also achieved with Aedes taeniorhynchus and A. albopictus, but these mosquitoes were significantly less tolerant to parasitism than C. pipiens quinquefasciatus. Strelkovimermis spiculatus did not infect or develop in any of the non-target hosts tested.

  18. FLAVIVIRUS SUSCPETIBILITY IN Aedes aegypti

    OpenAIRE

    FERNANDEZ, ILDEFONSO; muñoz, lourdes; farfan, jose arturo; beaty, barry; Black, William; gorrochotegi, norma

    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 difference among populations. We describe current researc...

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  1. Local impact of temperature and precipitation on West Nile virus infection in Culex species mosquitoes in northeast Illinois, USA

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    Haramis Linn

    2010-03-01

    Full Text Available Abstract Background Models of the effects of environmental factors on West Nile virus disease risk have yielded conflicting outcomes. The role of precipitation has been especially difficult to discern from existing studies, due in part to habitat and behavior characteristics of specific vector species and because of differences in the temporal and spatial scales of the published studies. We used spatial and statistical modeling techniques to analyze and forecast fine scale spatial (2000 m grid and temporal (weekly patterns of West Nile virus mosquito infection relative to changing weather conditions in the urban landscape of the greater Chicago, Illinois, region for the years from 2004 to 2008. Results Increased air temperature was the strongest temporal predictor of increased infection in Culex pipiens and Culex restuans mosquitoes, with cumulative high temperature differences being a key factor distinguishing years with higher mosquito infection and higher human illness rates from those with lower rates. Drier conditions in the spring followed by wetter conditions just prior to an increase in infection were factors in some but not all years. Overall, 80% of the weekly variation in mosquito infection was explained by prior weather conditions. Spatially, lower precipitation was the most important variable predicting stronger mosquito infection; precipitation and temperature alone could explain the pattern of spatial variability better than could other environmental variables (79% explained in the best model. Variables related to impervious surfaces and elevation differences were of modest importance in the spatial model. Conclusion Finely grained temporal and spatial patterns of precipitation and air temperature have a consistent and significant impact on the timing and location of increased mosquito infection in the northeastern Illinois study area. The use of local weather data at multiple monitoring locations and the integration of mosquito

  2. Comparative morphology of the pyloric armature of adult mosquitoes (Diptera: Culicidae).

    Science.gov (United States)

    Tuten, H C; Bridges, W C; Adler, P H

    2012-09-01

    The structure of the pyloric armature, hypothesized to aid in blood-meal digestion or parasite resistance, was compared quantitatively among the following 8 species in 5 genera of adult mosquitoes from the southeastern United States: Aedes albopictus, Aedes japonicus, Aedes triseriatus, Anopheles punctipennis, Culex pipiens s.l., Culex restuans, Orthopodomyia signifera, and Toxorhynchites rutilus. Females differed significantly among species in the structure of spines composing the armature, with Aedes spp. forming one general group, Culex spp. another, and An. punctipennis and Or. signifera a third. Relationships of species based on structural characters of the armature were consistent with recent culicid phylogenies. Although pyloric armature has been noted in mosquitoes and other insects, this is the first quantitative investigation of the mosquito pyloric armature.

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

    OpenAIRE

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

    2015-01-01

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

  4. Blood-feeding patterns of Culex quinquefasciatus and other culicines and implications for disease transmission in Mwea rice scheme, Kenya.

    Science.gov (United States)

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

    2008-05-01

    Studies were conducted in Mwea Rice Scheme, Kenya during the period April 2005 and January 2007 to determine the host-feeding pattern of culicine mosquitoes. Mosquitoes were collected indoors and outdoors and tested for human, bovine, goat, and donkey blood meals by an Enzyme-Linked Immunosorbent Assay. A total of 1,714 blood-engorged samples comprising Culex quinquefasciatus Say (96.1%), Culex annulioris Theobald (1.8%), Culex poicilipes Theobald (0.9%), Aedes cuminsi Theobald (1.0%), Aedes taylori Edwards (0.1%), and Mansonia africana Theobald (0.1%) were tested. Except for A. taylori, in which the single blood meal tested was of bovine origin, the other species fed mostly on both bovine (range 73.3-100%) and goats (range 50-100%). Donkeys were also common hosts for all species (range 19.4-23.5%) except A. taylori and M. africana. C. quinquefasciatus was the only species containing human blood meals (0.04), and indoor collected populations of this species had significantly higher frequency of human blood meals (9.8%) compared with outdoor-collected populations (3.0%). Mixed blood feeding was dominant among culicine species comprising 50.0%, 73.3%, 73.5%, 80.6%, and 94.1% of the samples for M. africana, C. poicilipes, C. quinquefasciatus, C. annulioris, and A. cuminsi, respectively. Ten mixed blood meal combinations including a mixture of all the four hosts were observed in C. quinquefasciatus, compared to one blood meal combination for M. Africana, and two combinations for C. poicilipes, C. annulioris, and A. cuminsi. Mixed bovine and goat blood meal was the most common combination among the five culicine species followed by a mixture of donkey, bovine, and goat blood meals. We conclude that culicine species in Mwea are least likely to be vectors of lymphatic filariasis due to their high "preference" for livestock over human hosts, but they present an increased risk for arbovirus transmission particularly Rift Valley Fever virus, in which domestic animals serve

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

    Science.gov (United States)

    Du, Y; Millar, J G

    1999-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Abhishek Pal

    2014-06-01

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

  7. Dispersion of Aedes aegypti (Linnaeus, 1762 and Aedes albopictus (Skuse, 1894 in the rural zone of north Paraná State

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    José Lopes

    2004-09-01

    Full Text Available Seventy-two tyres were placed in four transects (Northern, Southern, Eastern and Western, every 5 km, from the Londrina city limits to the rural areas, to verify the dispersion of Aedes aegypti and Ae. albopictus vectors. Mosquito larvae were collected fortnightly from August 1998 to August 1999. Data were organized according to the average number of larvae collected for each species in each collection site. A total of 62,517 mosquito larvae were collected and distributed into the following species: Aedes albopictus (21.71%; Ae. aegypti (5.54%; Ae. terrens (0.53%; Ae. fluviatilis (0.36%; Anopheles argyritarsi (0.01%; Culex quinquefasciatus (48.37%; Cx. mollis (8.88%; Cx. eduardoi (8.65%; Cx. corniger (0.61%; Cx. bigoti (0.24%; Cx. grupo coronator (0.12%; Limatus durhanii (4.61% e Toxorhynchites sp. (0.32%. There was a drastic decrease in the Ae. aegypti population from the city limits to the rural area (x1= 21.72 ± 4.71; x2=0.00 and an increase in the population of Ae. albopictus (x1 = 15.64 ± 2.73; x2 = 38.37 ± 8.87. Aedes aegypti was not present in the collection sites located 30 km away from the urban area; however, Ae. albopictus was found in all the sites. Although the frequency rate for the Aedes aegypti was low, both species were dispersed in the rural area studied. The redimensioning of these vectors’ control areas is recommended since rural areas can function as reservoirs for these species.Com o objetivo de avaliar a dispersão de Aedes aegypti e Ae. albopictus para a área rural, foram instalados pneus em quatro transectos (Norte, Sul, Leste e Oeste, a cada 5 Km, do limite da zona urbana de Londrina em direção a zona rural. Larvas de Culicidae foram coletadas quinzenalmente de agosto de 1998 a agosto de 1999. Um total de 62.517 larvas de Culicidae foram coletadas, distribuídas entre as seguintes espécies: Aedes albopictus (21.71%; Ae. aegypti (5.54%; Ae. terrens (0.53%; Ae. fluviatilis (0.36%; Anopheles argyritarsi (0

  8. Common Culex Mosquitoes Don't Transmit Zika Virus

    Science.gov (United States)

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

  9. 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?

    Science.gov (United States)

    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.

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

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    Song Chen

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

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

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    Ahid Silvia Maria Mendes

    2000-01-01

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

  12. Rhamnolipids: solution against Aedes aegypti?

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    Vinicius Luiz Silva

    2015-02-01

    Full Text Available Aedes aegypti mosquitoes are the primary transmitters of dengue fever, urban yellow fever and chikungunya viruses. This mosquito has developed resistance to the insecticides currently used to control their populations. These chemical insecticides are harmful to the environment and can have negative effects on human health. Rhamnolipids are environmentally compatible biological surfactants, but their insecticidal activity has not been extensively studied. The present study evaluated the potential larvicidal, insecticidal and repellent activities of rhamnolipids against Aedes aegypti. At concentrations of 800, 900 and 1000 mg/L, rhamnolipids eliminated all mosquito larvae in 18 hours and killed 100% of adults at 1000 mg/L. According to the results it may be conclude that rhamnolipids should be applied to control larvae and mosquitos besides present the repellency activity against Aedes aegypti.

  13. Ontogeny and distribution of cells in B lineage in the American leopard frog, Rana pipiens.

    Science.gov (United States)

    Zettergren, L D

    1982-01-01

    Two-color immunofluorescence techniques were used in order to trace the development and distribution of cells expressing immunoglobulin in Rana pipiens. Evidence is provided which suggests that (i) embryo-larval urogenital tissues are sites of generation of cells in B lineage, (ii) during ontogeny, there is a sequential expression of immunoglobulin isotypes on B cell surfaces, (iii) larvae are able to produce the full range of immunoglobulin clases found in adults, and (iv) at least two subpopulations of lymphocytes exist in Rana pipiens, sIg+ and sIg-; thymocytes and presumably peripheral T cells lack conventional surface immunoglobulin. Some ontogenetic and phylogenetic implications are discussed.

  14. miRNA genes of an invasive vector mosquito, Aedes albopictus.

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    Jinbao Gu

    Full Text Available Aedes albopictus, a vector of Dengue and Chikungunya viruses, is a robust invasive species in both tropical and temperate environments. MicroRNAs (miRNAs regulate gene expression and biological processes including embryonic development, innate immunity and infection. While a number of miRNAs have been discovered in some mosquitoes, no comprehensive effort has been made to characterize them from different developmental stages from a single species. Systematic analysis of miRNAs in Ae. albopictus will improve our understanding of its basic biology and inform novel strategies to prevent virus transmission. Between 10-14 million Illumina sequencing reads per sample were obtained from embryos, larvae, pupae, adult males, sugar-fed and blood-fed adult females. A total of 119 miRNA genes represented by 215 miRNA or miRNA star (miRNA* sequences were identified, 15 of which are novel. Eleven, two, and two of the newly-discovered miRNA genes appear specific to Aedes, Culicinae, and Culicidae, respectively. A number of miRNAs accumulate predominantly in one or two developmental stages and the large number that showed differences in abundance following a blood meal likely are important in blood-induced mosquito biology. Gene Ontology (GO analysis of the targets of all Ae. albopictus miRNAs provides a useful starting point for the study of their functions in mosquitoes. This study is the first systematic analysis of miRNAs based on deep-sequencing of small RNA samples of all developmental stages of a mosquito species. A number of miRNAs are related to specific physiological states, most notably, pre- and post-blood feeding. The distribution of lineage-specific miRNAs is consistent with mosquito phylogeny and the presence of a number of Aedes-specific miRNAs likely reflects the divergence between the Aedes and Culex genera.

  15. miRNA genes of an invasive vector mosquito, Aedes albopictus.

    Science.gov (United States)

    Gu, Jinbao; Hu, Wanqi; Wu, Jinya; Zheng, Peiming; Chen, Maoshan; James, Anthony A; Chen, Xiaoguang; Tu, Zhijian

    2013-01-01

    Aedes albopictus, a vector of Dengue and Chikungunya viruses, is a robust invasive species in both tropical and temperate environments. MicroRNAs (miRNAs) regulate gene expression and biological processes including embryonic development, innate immunity and infection. While a number of miRNAs have been discovered in some mosquitoes, no comprehensive effort has been made to characterize them from different developmental stages from a single species. Systematic analysis of miRNAs in Ae. albopictus will improve our understanding of its basic biology and inform novel strategies to prevent virus transmission. Between 10-14 million Illumina sequencing reads per sample were obtained from embryos, larvae, pupae, adult males, sugar-fed and blood-fed adult females. A total of 119 miRNA genes represented by 215 miRNA or miRNA star (miRNA*) sequences were identified, 15 of which are novel. Eleven, two, and two of the newly-discovered miRNA genes appear specific to Aedes, Culicinae, and Culicidae, respectively. A number of miRNAs accumulate predominantly in one or two developmental stages and the large number that showed differences in abundance following a blood meal likely are important in blood-induced mosquito biology. Gene Ontology (GO) analysis of the targets of all Ae. albopictus miRNAs provides a useful starting point for the study of their functions in mosquitoes. This study is the first systematic analysis of miRNAs based on deep-sequencing of small RNA samples of all developmental stages of a mosquito species. A number of miRNAs are related to specific physiological states, most notably, pre- and post-blood feeding. The distribution of lineage-specific miRNAs is consistent with mosquito phylogeny and the presence of a number of Aedes-specific miRNAs likely reflects the divergence between the Aedes and Culex genera.

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

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    Maria Anice Mureb Sallum

    2001-10-01

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

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

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    Oswaldo Paulo Forattini

    1995-08-01

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

  18. Microevolution of Aedes aegypti.

    Science.gov (United States)

    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

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

    Science.gov (United States)

    Su, T; Mulla, M S

    1998-06-01

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

  20. Pattern formation in artificially activated ectoderm (Rana pipiens and Ambystoma punctatum)

    NARCIS (Netherlands)

    Nieuwkoop, P.D.

    1963-01-01

    Presumptive ectoneuroderm of late blastulae or early gastrulae of Rana pipiens was partially activated by short-lasting disaggregation in Ca-free Holtfreter or Niu-Twitty solutions and subsequent reaggregation in normal solutions. The explants usually became dumbbell shaped and consisted respectivel

  1. Urbanization is a main driver for the larval ecology of Aedes mosquitoes in arbovirus-endemic settings in south-eastern Côte d'Ivoire.

    Directory of Open Access Journals (Sweden)

    Julien B Z Zahouli

    2017-07-01

    species Culex tigripes was commonly sampled, while Toxorhynchites and Eretmapodites were mostly collected in rural areas.In Côte d'Ivoire, urbanization is associated with high abundance of Aedes larvae and a predominance of artificial containers as breeding sites, mostly colonized by Ae. aegypti in urban areas. Natural containers are still common in rural areas harboring several Aedes species and, therefore, limiting the impact of systematic removal of discarded containers on the control of arbovirus diseases.

  2. Urbanization is a main driver for the larval ecology of Aedes mosquitoes in arbovirus-endemic settings in south-eastern Côte d'Ivoire.

    Science.gov (United States)

    Zahouli, Julien B Z; Koudou, Benjamin G; Müller, Pie; Malone, David; Tano, Yao; Utzinger, Jürg

    2017-07-01

    Culex tigripes was commonly sampled, while Toxorhynchites and Eretmapodites were mostly collected in rural areas. In Côte d'Ivoire, urbanization is associated with high abundance of Aedes larvae and a predominance of artificial containers as breeding sites, mostly colonized by Ae. aegypti in urban areas. Natural containers are still common in rural areas harboring several Aedes species and, therefore, limiting the impact of systematic removal of discarded containers on the control of arbovirus diseases.

  3. Truck-mounted Area-wide Application of Pyriproxyfen Targeting Aedes aegypti and Aedes albopictus in Northeast Florida

    Science.gov (United States)

    2014-12-01

    larval control , Aedes aegypti , Aedes albopictus INTRODUCTION Aedes albopictus (Skuse) (Asian tiger mosquito) and Ae. aegypti (L.) (yellow fever...Bull Fla Mosq Control Assoc 9:48– 52. Seng CM, Setha T, Nealon J, Socheat D, Nathan MB. 2008. Six months of Aedes aegypti control with a novel...TRUCK-MOUNTED AREA-WIDE APPLICATION OF PYRIPROXYFEN TARGETING AEDES AEGYPTI AND AEDES ALBOPICTUS IN NORTHEAST FLORIDA1 CARL W. DOUD,2,3 ANTHONY M

  4. STATUS KERENTANAN NYAMUK Aedes aegypti TERHADAP MALATHION

    OpenAIRE

    Ratnasari; Ishak, Hasanuddin; Selomo, Makmur

    2016-01-01

    Metode yang digunakan dalam penanggulangan nyamuk Aedes aegypti dewasa adalah dengan menggunakan insektisida jenis organophospat, yaitu malathion melalui fogging (pengasapan). Penelitian ini bertujuan untuk melihat status kerentanan nyamuk Aedes aegypti terhadap malathion 0,8%, 4%, dan 5%.Jenis penelitian yang dilakukan adalah penelitian eksperimental murni dengan rancangan penelitian post-test only with control group design. Jumlah sampel yang digunakan sebesar 1000 nyamuk Aedes aegypti yang...

  5. Cubiertas de auto abandonadas como sitios de cría de Culex eduardoi (Diptera: Culicidae en el Parque Provincial Pereyra Iraola, Provincia de Buenos Aires Discarded car tires as breeding sites of Culex eduardoi (Diptera: Culicidae in the Pereyra Iraola Provincial Park, Buenos Aires Province

    Directory of Open Access Journals (Sweden)

    Alejandra Rubio

    2011-06-01

    Full Text Available El conocimiento sobre la fauna de mosquitos que se cría en cubiertas de auto es realmente escaso en Argentina. El objetivo de este estudio fue caracterizar una población de inmaduros de Culex eduardoi Casal & Garcia en una acumulación de cubiertas abandonadas en un bosque suburbano de la Provincia de Buenos Aires. Entre noviembre 2009 y mayo 2010, se recolectaron mensualmente larvas de mosquitos en 27 cubiertas de auto abandonadas en un sector boscoso del Parque Provincial Pereyra Iraola. Se recolectaron en total 1.009 larvas del tercer y cuarto estadio de Cx. eduardoi, y el índice de contenedores (IC global fue 66,3% (106/160. Culex eduardoi estuvo presente durante todos los meses, aunque el IC difirió significativamente (x²(6 = 15,11; p The knowledge about tire-breeding mosquitoes is truly scarce in Argentina. The objective of this study was to characterize a population of immatures of Culex eduardoi Casal & Garcia, from a pile of abandoned tires located in a suburban forest of Buenos Aires Province. Between November 2009 and May 2010, mosquito larvae were monthly collected in 27 abandoned tires within a woody area of the Parque Provincial Pereyra Iraola. A total of 1009 third and fourth instar larvae of Cx. eduardoi were collected, and the overall container index (CI was 66.3% (106/160. Culex eduardoi was collected every month but the CI differed significantly (x²(6 = 15.11; p < 0.05, reaching maximum values in November and December (76 and 92.5% respectively. In spring, the relative abundance of larvae was also the highest, and the mean number of larvae collected per habitat was 9.5 (min. 3.5 in March; max.15.1 in November. Other mosquito species such as Cx. pipiens Linneo and Toxorhynchites theobaldi Dyar & Knab were also found in the studied containers. The present findings contribute with novel knowledge on culicids of tires in Argentina.

  6. Detection of novel insect flavivirus sequences integrated in Aedes albopictus (Diptera: Culicidae in Northern Italy

    Directory of Open Access Journals (Sweden)

    Tenorio Antonio

    2009-07-01

    Full Text Available Abstract The presence of DNA sequences integrated from a new flavivirus related to Cell Fusing Agent and Kamiti River Virus was identified in wild Aedes albopictus mosquito populations from the provinces of Trentino and Padova, Northern Italy. Field work was developed during August–October 2007 with BG-traps, and mosquitoes were screened for flavivirus and alphavirus. No alphavirus was detected, indicating that Chikungunya virus is not present in these mosquitoes in Trentino and Padova area. However, 21% of the pools were positive for flavivirus, further recognised with BLAST as similar to Kamiti River Virus. Phylogenetical analysis with 708 nucleotides from the NS5 gene identified this virus as a new member of the insect flavivirus clade, together with others like Kamiti River Virus, Cell Fusing Agent or Culex flavivirus, and in the group of those transmitted by Aedes. Furthermore, the treatment with RNAse, indicated that this flavivirus should be integrated in the genome of Ae. albopictus. These results propose that these sequences are transmitted by both sexes, and with different prevalence in the studied populations, and support the idea of a widespread distribution of integrated genomes in several mosquitoes from different areas, as first demonstrated with Cell Silent Agent. Evolutionary implications of this discovery and application in flavivirus phylogeny are discussed.

  7. Principales criaderos para Aedes aegypti y culícidos asociados, Argentina

    Directory of Open Access Journals (Sweden)

    Stein Marina

    2002-01-01

    Full Text Available Se identificaron criaderos de Aedes (Stegomyia aegypti en dos ciudades de la provincia del Chaco (Noreste de Argentina: Presidencia Roque Saenz Peña y Machagai. Los recipientes encontrados en los patios de las viviendas capaces de colectar agua se clasificaron según tipo y tamaño, se contaron y examinaron. Aedes aegypti y Culex quinquefasciatus fueron las especies mas abundantes, encontrándose además Cx. maxi, Cx. saltanensis y Ochlerotatus scapularis. Los neumáticos y cajas de baterías para autos fueron los recipientes que más aportaron a la producción de formas inmaduras de los culícidos colectados. Las lluvias fueron un factor importante para la proliferacion de Ae. aegypti, así como también el habito comun en la población de guardar recipientes en sus casas que permitan el desarrollo de estos culícidos.

  8. Principales criaderos para Aedes aegypti y culícidos asociados, Argentina

    Directory of Open Access Journals (Sweden)

    Marina Stein

    2002-10-01

    Full Text Available Se identificaron criaderos de Aedes (Stegomyia aegypti en dos ciudades de la provincia del Chaco (Noreste de Argentina: Presidencia Roque Saenz Peña y Machagai. Los recipientes encontrados en los patios de las viviendas capaces de colectar agua se clasificaron según tipo y tamaño, se contaron y examinaron. Aedes aegypti y Culex quinquefasciatus fueron las especies mas abundantes, encontrándose además Cx. maxi, Cx. saltanensis y Ochlerotatus scapularis. Los neumáticos y cajas de baterías para autos fueron los recipientes que más aportaron a la producción de formas inmaduras de los culícidos colectados. Las lluvias fueron un factor importante para la proliferacion de Ae. aegypti, así como también el habito comun en la población de guardar recipientes en sus casas que permitan el desarrollo de estos culícidos.

  9. Rhamnolipids: solution against Aedes aegypti?

    OpenAIRE

    Silva, Vinicius L.; Lovagliol, Roberta B. [UNESP; Von Zuben,Claudio J.; Contierol, Jonas [UNESP

    2015-01-01

    Aedes aegypti mosquitoes are the primary transmitters of dengue fever, urban yellow fever, and chikungunya viruses. This mosquito has developed resistance to the insecticides currently used to control their populations. These chemical insecticides are harmful to the environment and can have negative effects on human health. Rhamnolipids are environmentally compatible biological surfactants, but their insecticidal activity has not been extensively studied. The present study evaluated the poten...

  10. Gene editing in Aedes aegypti

    OpenAIRE

    Aryan, Azadeh

    2013-01-01

    Aedes aegypti (Ae. aegypti) is one of the most important vectors of dengue, chikungunya and yellow fever viruses. The use of chemical control strategies such as insecticides is associated with problems including the development of insecticide resistance, side effects on animal and human health, and environmental concerns. Because current methods have not proven sufficient to control these diseases, developing novel, genetics-based, control strategies to limit the transmission of disease is ur...

  11. Trehalase inhibition in Aedes aegypti

    OpenAIRE

    Logan, Carolina Isabel

    2008-01-01

    Aedes aegypti is the principal vector of Dengue virus, the most important mosquito-borne viral disease affecting humans. Infection of Ae. aegypti larvae by the trematode Plagiorchis elegans leads to a disruption of carbohydrate metabolism by preventing the conversion of trehalose to glucose, and the production of an oviposition deterrent compound. This thesis examines the dose-dependent effects of a trehalase inhibitor, Validoxylamine A (VAA), on Ae. aegypti. VAA had no noticeable effect on l...

  12. Nanobiotechnology Solutions against Aedes aegypti

    OpenAIRE

    Durán, Nelson; Islan,German A.; Durán, Marcela; Castro, Guillermo R.

    2016-01-01

    United Nations Children's Fund (UNICEF)/United Nations Development Programme (UNDP)/World Bank/World Health Organization (WHO) implemented the Training in Tropical Diseases (TDR) program with excellent results; however, due to current challenges, this active program requires new and innovative solutions. Nowadays, Aedes aegyptis-borne diseases can be added among neglected diseases. Surveillance and control must be considered owing to a great risk of infection with dengue, chikungunya and zika...

  13. Rhamnolipids: solution against Aedes aegypti?

    OpenAIRE

    Vinicius Luiz Silva; Roberta Barros Lovaglio; Claudio José Von Zuben; Jonas eContiero

    2015-01-01

    Aedes aegypti mosquitoes are the primary transmitters of dengue fever, urban yellow fever and chikungunya viruses. This mosquito has developed resistance to the insecticides currently used to control their populations. These chemical insecticides are harmful to the environment and can have negative effects on human health. Rhamnolipids are environmentally compatible biological surfactants, but their insecticidal activity has not been extensively studied. The present study evaluated the potent...

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

    Science.gov (United States)

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

    2011-06-01

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

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

    Directory of Open Access Journals (Sweden)

    André L. A. Melo

    2009-03-01

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

  16. Globally invasive, withdrawing at home: Aedes albopictus and Aedes japonicus facing the rise of Aedes flavopictus

    Science.gov (United States)

    Chaves, Luis Fernando

    2016-11-01

    It has been suggested that climate change may have facilitated the global expansion of invasive disease vectors, since several species have expanded their range as temperatures have warmed. Here, we present results from observations on two major global invasive mosquito vectors (Diptera: Culicidae), Aedes albopictus (Skuse) and Aedes japonicus (Theobald), across the altitudinal range of Mt. Konpira, Nagasaki, Japan, a location within their native range, where Aedes flavopictus Yamada, formerly a rare species, has now become dominant. Spatial abundance patterns of the three species suggest that temperature is an important factor influencing their adult distribution across the altitudinal range of Mt. Konpira. Temporal abundance patterns, by contrast, were associated with rainfall and showed signals of density-dependent regulation in the three species. The spatial and temporal analysis of abundance patterns showed that Ae. flavopictus and Ae. albopictus were negatively associated, even when accounting for differential impacts of weather and other environmental factors in their co-occurrence patterns. Our results highlight a contingency in the expansion of invasive vectors, the potential emergence of changes in their interactions with species in their native communities, and raise the question of whether these changes might be useful to predict the emergence of future invasive vectors.

  17. Noncoding subgenomic flavivirus RNA is processed by the mosquito RNA interference machinery and determines West Nile virus transmission by Culex pipiens mosquitoes

    NARCIS (Netherlands)

    Göertz, G.P.; Fros, J.J.; Miesen, P.; Vogels, C.B.F.; Bent, van der M.L.; Geertsema, C.; Koenraadt, C.J.M.; Rij, van R.P.; Oers, van M.M.; Pijlman, G.P.

    2016-01-01

    Flaviviruses, such as Zika virus, yellow fever virus, dengue virus, and West Nile virus (WNV), are a serious concern for human health. Flaviviruses produce an abundant noncoding subgenomic flavivirus RNA (sfRNA) in infected cells. sfRNA results from stalling of the host 5=-3= exoribonuclease XRN1

  18. Noncoding Subgenomic Flavivirus RNA Is Processed by the Mosquito RNA Interference Machinery and Determines West Nile Virus Transmission by Culex pipiens Mosquitoes

    NARCIS (Netherlands)

    Goertz, G.P.; Fros, J.J.; Miesen, P.; Vogels, C.B.F.; Bent, M.L. van der; Geertsema, C.; Koenraadt, C.J.M.; Rij, R.P. van; Oers, M.M. van; Pijlman, G.P.

    2016-01-01

    Flaviviruses, such as Zika virus, yellow fever virus, dengue virus, and West Nile virus (WNV), are a serious concern for human health. Flaviviruses produce an abundant noncoding subgenomic flavivirus RNA (sfRNA) in infected cells. sfRNA results from stalling of the host 5'-3' exoribonuclease XRN1/Pa

  19. Noncoding subgenomic flavivirus RNA is processed by the mosquito RNA interference machinery and determines West Nile virus transmission by Culex pipiens mosquitoes

    NARCIS (Netherlands)

    Göertz, G.P.; Fros, J.J.; Miesen, P.; Vogels, C.B.F.; Bent, van der M.L.; Geertsema, C.; Koenraadt, C.J.M.; Rij, van R.P.; Oers, van M.M.; Pijlman, G.P.

    2016-01-01

    Flaviviruses, such as Zika virus, yellow fever virus, dengue virus, and West Nile virus (WNV), are a serious concern for human health. Flaviviruses produce an abundant noncoding subgenomic flavivirus RNA (sfRNA) in infected cells. sfRNA results from stalling of the host 5=-3= exoribonuclease XRN1

  20. Development of resistance of propoxur selected Culex pipiens pallens%残杀威选育淡色库蚊抗药性研究

    Institute of Scientific and Technical Information of China (English)

    张春华; 李新华; 戴伟; 徐强; 甄天民

    2005-01-01

    目的实验选育抗性品系的蚊虫,探讨抗药性的发生发展规律,为抗性媒蚊的防制研究提供依据.方法在实验室条件下,用残杀威以LC50的剂量处理Ⅳ龄幼虫,选育残杀威抗性品系.按照WHO生物测定法,测定抗残杀威品系对多种杀虫剂的敏感性. 结果选育到23代时,抗性比敏感品系增加11.12倍,之后抗性趋于稳定.通过测定发现残杀威抗性品系对其它化学杀虫剂有交互抗性.讨论使用杀虫剂可在短期内使蚊虫产生抗性,抗性水平增长较快,而且对作用机理相近的杀虫剂也产生交互抗性.

  1. Noncoding Subgenomic Flavivirus RNA Is Processed by the Mosquito RNA Interference Machinery and Determines West Nile Virus Transmission by Culex pipiens Mosquitoes

    NARCIS (Netherlands)

    Goertz, G.P.; Fros, J.J.; Miesen, P.; Vogels, C.B.F.; Bent, M.L. van der; Geertsema, C.; Koenraadt, C.J.M.; Rij, R.P. van; Oers, M.M. van; Pijlman, G.P.

    2016-01-01

    Flaviviruses, such as Zika virus, yellow fever virus, dengue virus, and West Nile virus (WNV), are a serious concern for human health. Flaviviruses produce an abundant noncoding subgenomic flavivirus RNA (sfRNA) in infected cells. sfRNA results from stalling of the host 5'-3' exoribonuclease

  2. Noncoding subgenomic flavivirus RNA is processed by the mosquito RNA interference machinery and determines West Nile virus transmission by Culex pipiens mosquitoes

    NARCIS (Netherlands)

    Göertz, G.P.; Fros, J.J.; Miesen, P.; Vogels, C.B.F.; Bent, van der M.L.; Geertsema, C.; Koenraadt, C.J.M.; Rij, van R.P.; Oers, van M.M.; Pijlman, G.P.

    2016-01-01

    Flaviviruses, such as Zika virus, yellow fever virus, dengue virus, and West Nile virus (WNV), are a serious concern for human health. Flaviviruses produce an abundant noncoding subgenomic flavivirus RNA (sfRNA) in infected cells. sfRNA results from stalling of the host 5=-3= exoribonuclease

  3. 四种盘式蚊香对淡色库蚊的药效实验研究%Efficacy of 4 Mosquitoes Coils against Culex Pipiens Pallens

    Institute of Scientific and Technical Information of China (English)

    张晓华; 陈超; 石华

    2003-01-01

    @@ 随着夏季的来临,蚊虫的相继出现,使得其传播的各种疾病也相继增加,这就迫使我们不得不做好蚊虫的防治工作.对于灭蚊人们使用频率最高的应该是蚊香.在广大的农村地区,绝大部分农户采用蚊香来防蚊,因为它价廉物美,使用方便.但是有时人们因为缺乏对蚊香基本常识的认识而一味追求便宜买一些劣质的,含有违禁药物或者有效成分较低的蚊香防蚊,从而达不到预期效果,甚至还会影响人们的身体健康.为此,我们选用4个生产单位提供的盘式蚊香进行了生物药效对比.现将实验结果报告如下:

  4. 三种蚊香对淡色库蚊的效果观察%The efficacy of three formulations of mosquito coil incense against Culex pipiens pallens

    Institute of Scientific and Technical Information of China (English)

    宋秀平; 刘起勇

    2003-01-01

    目的:3种蚊香对淡色库蚊的效果.方法:采用GB13917-1992和GB/T17322-1998规定的测试方法和评价标准进行.结果:在实验室3种蚊香对淡色库蚊KT50为2.27~4.98min,24h死亡率为91.4%~100%;在模拟现场2 h击倒率为100%,24h死亡率为96%~100%.结论:3种蚊香对蚊虫均能达到较好的杀灭效果.

  5. Summary of field trials in 1964-69 in Rangoon, Burma, of organophosphorus larvicides and oils against Culex pipiens fatigens larvae in polluted water.

    Science.gov (United States)

    Self, L S; Tun, M M

    1970-01-01

    In tests in Rangoon, Burma, of the larvicidal activity of various organophosphorus compounds against C. p. fatigans, it was found that the activity usually lasted much longer in septic tanks and pit latrines than in open drains. Dursban, Abate, fenthion and several other emulsifiable concentrates caused high larval mortality at a concentration of 0.05 ppm but 0.5 ppm was normally required to obtain a minimum of 1-2 weeks of complete larval control. For the desired residual activity, dosages about 40-400 times the laboratory LC(95) values were normally required, depending on the compound used.The most effective formulation was Dursban emulsifiable concentrate, which, at a concentration of 0.5 ppm, was effective for 3, 7 and 12 weeks in concrete drains, pit latrines and septic tanks, respectively. Petroleum oils applied at rates of 25-40 US gal/ac (approx. 237 l/ha-380 l/ha) and a pyrethrum derivative at a concentration of 1.0 ppm were toxic to larvae but not highly residual. Some emulsifiable-concentrate/oil mixtures appeared to be outstandingly effective, although inconsistent results also occurred. Granular formulations were normally less effective than the emulsifiable concentrates.

  6. ACTIVITY OF FREE AND CLAY-BOUND INSECTICIDAL PROTEINS FROM BACILLUS THURINGIENSIS SUBSP. ISRAELENSIS AGAINST THE MOSQUITO, CULEX PIPIENS. (R826107)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  7. Control of Culex pipiens fatigans(W) by the larvivorous fish Poecillia reticulata and by removal of debris from the breeding habitat.

    Science.gov (United States)

    Phan-Urai, P; Nelson, M J; Phanthumachinda, B

    1976-03-01

    Twice weekly removal of floating debris from two polluted ponds in Bangkok resulted in 75% reduction of immature populations of C.p. fatigans for seven weeks. Subsequent introduction of the guppy Poecilia reticulata at 10 fish per m2 further reduced the aquatic population to 2% of the pretreatment level during 12 weeks. When debris removal was discontinued, partial recovery of the larval density was observed. When fish were introduced in a plot without prior debris removal, there was no reduction of the mosquito population, and when only part of the debris was removed from one plot, the reduction was immediate.

  8. ACTIVITY OF FREE AND CLAY-BOUND INSECTICIDAL PROTEINS FROM BACILLUS THURINGIENSIS SUBSP. ISRAELENSIS AGAINST THE MOSQUITO, CULEX PIPIENS. (R826107)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

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

    Science.gov (United States)

    Reeves, Will K; Darsie, Richard F

    2003-03-01

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

  10. Complex spatial dynamics maintain northern leopard frog (Lithobates pipiens) genetic diversity in a temporally varying landscape

    Science.gov (United States)

    Mushet, David M.; Euliss, Ned H.; Chen, Yongjiu; Stockwell, Craig A.

    2013-01-01

    In contrast to most local amphibian populations, northeastern populations of the Northern Leopard Frog (Lithobates pipiens) have displayed uncharacteristically high levels of genetic diversity that have been attributed to large, stable populations. However, this widely distributed species also occurs in areas known for great climatic fluctuations that should be reflected in corresponding fluctuations in population sizes and reduced genetic diversity. To test our hypothesis that Northern Leopard Frog genetic diversity would be reduced in areas subjected to significant climate variability, we examined the genetic diversity of L. pipiens collected from 12 sites within the Prairie Pothole Region of North Dakota. Despite the region's fluctuating climate that includes periods of recurring drought and deluge, we found unexpectedly high levels of genetic diversity approaching that of northeastern populations. Further, genetic structure at a landscape scale was strikingly homogeneous; genetic differentiation estimates (Dest) averaged 0.10 (SD = 0.036) across the six microsatellite loci we studied, and two Bayesian assignment tests (STRUCTURE and BAPS) failed to reveal the development of significant population structure across the 68 km breadth of our study area. These results suggest that L. pipiens in the Prairie Pothole Region consists of a large, panmictic population capable of maintaining high genetic diversity in the face of marked climate variability.

  11. [BLOODSUCKING MOSQUITOES (DIPTERA: CULICIDAE) IN, THE TULA REGION ARE POTENTIAL VECTORS OF DIROFILARIAS].

    Science.gov (United States)

    Bogacheva, A S; Ganushkina, L A; Lopatina, Yu V

    2015-01-01

    Bloodsucking mosquitoes were collected in Tula and its Region in May to August 2013-2014. The fauna included 17 species from 5 genera in the subfamily Culicinae and Anopheles maculipennis complex in the subsystem Anophelinae. Ochlerotatus cantans was a dominant species in the collections. The dominant species also included Aedes einereus, Ae. vexans, Ae. geniculatus, Och. diantaeus, Och. intrudens, Och. Cataphylla, and Culex pipiens. The possible value of different mosquito species Dirofilaria repens and D. immitis as vectors of dirofilarasis was discussed.

  12. Pea Albumin 1 Subunit b (PA1b), a Promising Bioinsecticide of Plant Origin.

    OpenAIRE

    Corinne Royer; Vanessa Eyraud; Lamis Karaki; Frédéric Gressent; Pedro Da Silva

    2011-01-01

    International audience; PA1b (Pea Albumin 1, subunit b) is a peptide extract from pea seeds showing significant insecticidal activity against certain insects, such as cereal weevils (genus Sitophilus), the mosquitoes Culex pipiens and Aedes aegyptii, and certain species of aphids. PA1b has great potential for use on an industrial scale and for use in organic farming: it is extracted from a common plant; it is a peptide (and therefore suitable for transgenic applications); it can withstand man...

  13. ФАУНА КОМАРОВ (Diptera, Culicidae) ВОСТОЧНОГО ВЕРХНЕВОЛЖЬЯ РОССИЙСКОЙ ФЕДЕРАЦИИ

    OpenAIRE

    Смирнов, А.; Егоров, С.; Абарыкова, О.; Петров, Ю.

    2006-01-01

    As a result of the studies of the urban ecosystem of the city of Zhytomyr we have found out 21 species (5 genera) of mosquitoes. The Aedes genus is the most numerous (47 %, 15 species) with Ae. cinereus Mg. being dominant. Representatives of the Anopheles genus amount 37 %, 2 species, An. maculipennis Mg. being dominant. The Culex genus is less numerous (16 %, 2 species) with Cx. pipiens pipiens L. being dominant. Representatives of the Mansonia (M. richiardii Fic.) and Culiseta (Cs. аnnulata...

  14. Key characters for identifying Aedes bahamensis and Aedes albopictus in North America, north of Mexico.

    Science.gov (United States)

    Darsie, R F

    1992-09-01

    Aedes bahamensis, a species recently introduced into southern Florida represents the first member of the subgenus Howardina to be found in the United States. Its separation from all other Nearctic Aedes is the subject of this work, integrating it into the North American mosquito keys (Darsie and Ward 1981). The key revisions presented are expanded to include the other exotic species now found in the United States, Aedes albopictus.

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

    Directory of Open Access Journals (Sweden)

    Anielly Ferreira-de-Brito

    Full Text Available 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.

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

    Science.gov (United States)

    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

  17. De novo assembly of the Aedes aegypti genome using Hi-C yields chromosome-length scaffolds.

    Science.gov (United States)

    Dudchenko, Olga; Batra, Sanjit S; Omer, Arina D; Nyquist, Sarah K; Hoeger, Marie; Durand, Neva C; Shamim, Muhammad S; Machol, Ido; Lander, Eric S; Aiden, Aviva Presser; Aiden, Erez Lieberman

    2017-04-07

    The Zika outbreak, spread by the Aedes aegypti mosquito, highlights the need to create high-quality assemblies of large genomes in a rapid and cost-effective way. Here we combine Hi-C data with existing draft assemblies to generate chromosome-length scaffolds. We validate this method by assembling a human genome, de novo, from short reads alone (67× coverage). We then combine our method with draft sequences to create genome assemblies of the mosquito disease vectors Aeaegypti and Culex quinquefasciatus, each consisting of three scaffolds corresponding to the three chromosomes in each species. These assemblies indicate that almost all genomic rearrangements among these species occur within, rather than between, chromosome arms. The genome assembly procedure we describe is fast, inexpensive, and accurate, and can be applied to many species.

  18. Detection of Aedes aegypti, Aedes albopictus, and Aedes koreicus in the Area of Sochi, Russia.

    Science.gov (United States)

    Ganushkina, Ludmila A; Patraman, Ivan V; Rezza, Giovanni; Migliorini, Luigi; Litvinov, Serguei K; Sergiev, Vladimir P

    2016-01-01

    Following the identification of Aedes (Ae.) aegypti in the Sochi area in Russia at the beginning of 2000, entomological surveys were conducted during the summers of 2007, 2011, and 2012, leading to the identification of Ae. albopictus and Ae. koreicus. These findings highlight Russia as being the only country in the World Health Organization European Region with a documented presence of both Ae. aegypti and Ae. albopictus mosquitoes. Both mosquito species are found on the coasts of the Black Sea. Control measures are needed to reduce the possible risks of importing exotic vector-borne infections, such as dengue and chikungunya.

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

    Science.gov (United States)

    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

    2016-09-01

    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. 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. 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.

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

    Directory of Open Access Journals (Sweden)

    Sonja Hall-Mendelin

    2016-09-01

    Full Text Available 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.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.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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2007-12-01

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

  3. 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

    Science.gov (United States)

    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

  4. Household survey of container-breeding mosquitoes and climatic factors influencing the prevalence of Aedes aegypti (Diptera:Culicidae) in Makkah City, Saudi Arabia

    Institute of Scientific and Technical Information of China (English)

    Al Thabiany Aziz; Hamdan Ahmad; Wan Fatma Zuharah; Ahmad Saad Ramli; Fumio Miake; Hamady Dieng; Abu Hassan Ahmad; Jazem A Mahyoub; Abdulhafis M Turkistani; Hatabbi Mesed; Salah Koshike; Tomomitsu Satho; MR Che Salmah

    2012-01-01

    Objective: To investigate the prevalence of container breeding mosquitoes with emphasis on the seasonality and larval habitats of Aedes aegypti (Ae. aegypti) in Makkah City, adjoining an environmental monitoring and dengue incidence. Methods: Monthly visits were performed between April 2008 and March 2009 to randomly selected houses. During each visit, mosquito larvae were collected from indoors and outdoors containers by either dipping or pipetting. Mosquitoes were morphologically identified. Data on temperature, relative humidity, rain/precipitations during the survey period was retrieved from governmental sources and analyzed. Results: The city was warmer in dry season (DS) than wet season (WS). No rain occurred at all during DS and even precipitations did fall, wetting events were much greater during WS. Larval survey revealed the co-breeding of Aedes, Culex and Anopheles in a variety of artificial containers in and around homes. 32109 larvae representing 1st , 2nd, 3rd, and 4th stages were collected from 22618 container habitats. Culicines was far the commonest and Aedes genus was as numerous as the Culex population. Ae. aegypti larval abundance exhibited marked temporal variations, overall, being usually more abundant during WS. Ten types of artificial containers were found with developing larvae. 70% of these habitats were located indoors. 71.42% of indoor containers were permanent and 28.58% was semi-permanent during WS. Cement tanks was the only container type permanent during DS. Ae. aegypti larval indices (CI, HI, BI) recorded were greater during WS. Conclusions: Taken together, these results indicate a high risk of dengue transmission in the holy city.

  5. Aedes cadherin mediates the in vivo toxicity of the Cry11Aa toxin to Aedes aegypti.

    Science.gov (United States)

    Lee, Su-Bum; Chen, Jianwu; Aimanova, Karlygash G; Gill, Sarjeet S

    2015-06-01

    Cadherin plays an important role in the toxicity of Bacillus thuringiensis Cry proteins. We previously cloned a full-length cadherin from Aedes aegypti larvae and reported this protein binds Cry11Aa toxin from B. thuringiensis subsp. israelensis with high affinity, ≈16.7nM. Based on these results, we investigated if Aedes cadherin is involved in the in vivo toxicity of Cry11Aa toxin to Ae. aegypti. We established a mosquito cell line stably expressing the full-length Aedes cadherin and transgenic mosquitoes with silenced Aedes cadherin expression. Cells expressing the Aedes cadherin showed increased sensitivity to Cry11Aa toxin. Cry11Aa toxin at 400nM killed approximately 37% of the cells in 3h. Otherwise, transgenic mosquitoes with silenced Aedes cadherin expression showed increased tolerance to Cry11Aa toxin. Furthermore, cells expressing Aedes cadherin triggered Cry11Aa oligomerization. These results show the Aedes cadherin plays a pivotal role in Cry11Aa toxicity to Ae. aegypti larvae by mediating Cry11Aa oligomerization. However, since high toxicity was not obtained in cadherin-expressing cells, an additional receptor may be needed for manifestation of full toxicity. Moreover, cells expressing Aedes cadherin were sensitive to Cry4Aa and Cry11Ba, but not Cry4Ba. However transgenic mosquitoes with silenced Aedes cadherin expression showed no tolerance to Cry4Aa, Cry4Ba, and Cry11Ba toxins. These results suggest that while Aedes cadherin may mediate Cry4Aa and Cry11Ba toxicity, this cadherin but is not the main receptor of Cry4Aa, Cry4Ba and Cry11Ba toxin in Ae. aegypti.

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

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2006-06-01

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

  8. A survey of mosquitoes breeding in used tires in Spain for the detection of imported potential vector species.

    Science.gov (United States)

    Roiz, D; Eritja, R; Escosa, R; Lucientes, J; Marquès, E; Melero-Alcíbar, R; Ruiz, S; Molina, R

    2007-06-01

    The used tire trade has facilitated the introduction, spread, and establishment of the Asian tiger mosquito, Aedes albopictus, and other mosquito species in several countries of America, Africa, Oceania, and Europe. A strategy for detecting these imported mosquito vectors was developed in Spain during 2003-2004 by EVITAR (multidisciplinary network for the study of viruses transmitted by arthropods and rodents). A survey in 45 locations found no invasive species. Eight autochthonous species of mosquitoes were detected in used tires, including Culex pipiens, Cx. hortensis, Cx. modestus, Anopheles atroparvus, An. claviger, Culiseta longiareolata, Cs. annulata, and Aedes caspius. Dominant species were Cx. pipiens and Cs. longiareolata. Aedes caspius was found in only once, near its natural breeding habitat. Considering the recent discovery of an established population of Ae. albopictus in Catalonia, the increasing commerce of used tires in Spain for recycling, storage, and recapping might greatly contribute to the rapid spread of this species across the Iberian Peninsula.

  9. Prevalence of the pathogenic chytrid fungus, Batrachochytrium dendrobatidis, in an endangered population of northern leopard frogs, Rana pipiens

    Directory of Open Access Journals (Sweden)

    Govindarajulu Purnima

    2010-03-01

    Full Text Available Abstract Background Emerging infectious diseases threaten naïve host populations with extinction. Chytridiomycosis, an emerging infectious disease of amphibians, is caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd and has been linked to global declines in amphibians. Results We monitored the prevalence of Bd for four years in the Northern leopard frog, Rana pipiens, which is critically imperiled in British Columbia (BC, Canada. The prevalence of Bd initially increased and then remained constant over the last three years of the study. Young of the year emerging from breeding ponds in summer were rarely infected with Bd. Some individuals cleared their Bd infections and the return rate between infected and uninfected individuals was not significantly different. Conclusions The BC population of R. pipiens appears to have evolved a level of resistance that allows it to co-exist with Bd. However, this small population of R. pipiens remains vulnerable to extinction.

  10. Dispersal of Engineered Male Aedes aegypti Mosquitoes.

    Science.gov (United States)

    Winskill, Peter; Carvalho, Danilo O; Capurro, Margareth L; Alphey, Luke; Donnelly, Christl A; McKemey, Andrew R

    2015-11-01

    Aedes aegypti, the principal vector of dengue fever, have been genetically engineered for use in a sterile insect control programme. To improve our understanding of the dispersal ecology of mosquitoes and to inform appropriate release strategies of 'genetically sterile' male Aedes aegypti detailed knowledge of the dispersal ability of the released insects is needed. The dispersal ability of released 'genetically sterile' male Aedes aegypti at a field site in Brazil has been estimated. Dispersal kernels embedded within a generalized linear model framework were used to analyse data collected from three large scale mark release recapture studies. The methodology has been applied to previously published dispersal data to compare the dispersal ability of 'genetically sterile' male Aedes aegypti in contrasting environments. We parameterised dispersal kernels and estimated the mean distance travelled for insects in Brazil: 52.8 m (95% CI: 49.9 m, 56.8 m) and Malaysia: 58.0 m (95% CI: 51.1 m, 71.0 m). Our results provide specific, detailed estimates of the dispersal characteristics of released 'genetically sterile' male Aedes aegypti in the field. The comparative analysis indicates that despite differing environments and recapture rates, key features of the insects' dispersal kernels are conserved across the two studies. The results can be used to inform both risk assessments and release programmes using 'genetically sterile' male Aedes aegypti.

  11. Software for pattern recognition of the larvae of Aedes aegypti and Aedes albopictus

    Directory of Open Access Journals (Sweden)

    São Thiago André Iwersen de

    2002-01-01

    Full Text Available Software for pattern recognition of the larvae of mosquitoes Aedes aegypti and Aedes albopictus, biological vectors of dengue and yellow fever, has been developed. Rapid field identification of larva using a digital camera linked to a laptop computer equipped with this software may greatly help prevention campaigns.

  12. Software for pattern recognition of the larvae of Aedes aegypti and Aedes albopictus

    OpenAIRE

    São Thiago André Iwersen de; Kupek Emil; Ferreira Neto Joaquim Alves; São Thiago Paulo de Tarso

    2002-01-01

    Software for pattern recognition of the larvae of mosquitoes Aedes aegypti and Aedes albopictus, biological vectors of dengue and yellow fever, has been developed. Rapid field identification of larva using a digital camera linked to a laptop computer equipped with this software may greatly help prevention campaigns.

  13. Oviposition Substrate Selection by Florida Mosquitoes in Response to Pathogen-Infected Conspecific Larvae

    National Research Council Canada - National Science Library

    Catherine M. Zettel Nalen; Sandra A. Allan; James J. Becnel; Phillip E. Kaufman

    2013-01-01

    .... These included Aedes aegypti infected with Edhazardia aedis, Aedes albopictus infected with Vavraia culicis, and Culex quinquefasciatus infected with Culex nigripalpus nucleopolyhedrovirus (CuniNPV...

  14. Phylogenetic relationships of leopard frogs (Rana pipiens complex) from an isolated coastal mountain range in southern Sonora, Mexico.

    Science.gov (United States)

    Pfeiler, E; Markow, T A

    2008-10-01

    Mitochondrial DNA sequence data from the control region and 12S rRNA in leopard frogs from the Sierra El Aguaje of southern Sonora, Mexico, together with GenBank sequences, were used to infer taxonomic identity and provide phylogenetic hypotheses for relationships with other members of the Rana pipiens complex. We show that frogs from the Sierra El Aguaje belong to the Rana berlandieri subgroup, or Scurrilirana clade, of the R. pipiens group, and are most closely related to Rana magnaocularis from Nayarit, Mexico. We also provide further evidence that Rana magnaocularis and R. yavapaiensis are close relatives.

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

    Science.gov (United States)

    Almirón, Walter R.; Gardenal, Cristina N.

    2017-01-01

    Culex bidens and C. interfor, implicated in arbovirus transmission in Argentina, are sister species, only distinguishable by feature of the male genitalia; however, intermediate specimens of the species in sympatry have been found. Fourth-instar larvae and females of both species share apomorphic features, and this lack of clear distinction creates problems for specific identification. Geometric morphometric traits of these life stages also do not distinguish the species. The aim of the present study was to assess the taxonomic status of C. bidens and C. interfor using two mitochondrial genes and to determine the degree of their reproductive isolation using microsatellite loci. Sequences of the ND4 and COI genes were concatenated in a matrix of 993 nucleotides and used for phylogenetic and distance analyses. Bayesian and maximum parsimony inferences showed a well resolved and supported topology, enclosing sequences of individuals of C. bidens (0.83 BPP, 73 BSV) and C. interfor (0.98 BPP, 97 BSV) in a strong sister relationship. The mean K2P distance within C. bidens and C. interfor was 0.3% and 0.2%, respectively, and the interspecific variation was 2.3%. Bayesian clustering also showed two distinct mitochondrial lineages. All sequenced mosquitoes were successfully identified in accordance with the best close match algorithm. The low genetic distance values obtained indicate that the species diverged quite recently. Most morphologically intermediate specimens of C. bidens from Córdoba were heterozygous for the microsatellite locus GT51; the significant heterozygote excess observed suggests incomplete reproductive isolation. However, C. bidens and C. interfor should be considered good species: the ventral arm of the phallosome of the male genitalia and the ND4 and COI sequences are diagnostic characters. PMID:28235083

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

    Science.gov (United States)

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

    2016-12-22

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

  17. Functional Development of the Octenol Response in Aedes aegypti

    Science.gov (United States)

    2013-03-07

    ORIGINAL RESEARCH ARTICLE published: 07 March 2013 doi: 10.3389/fphys.2013.00039 Functional development of the octenol response in Aedes aegypti ...l’Insecte, Signalisation et Communication, Université Pierre et Marie Curie, UMR 1272, F-75252 Paris, France. Attraction of female Aedes aegypti ...mosquitoes. Keywords: odorant receptor, gustatory receptor, octenol, CO2, olfaction, Aedes aegypti , development INTRODUCTION Female Aedes aegypti

  18. Ecological interactions in Aedes species on Reunion Island

    OpenAIRE

    Bagny Beilhe, L.; Delatte, H.; Juliano, S. A.; Fontenille, Didier; Quilici, S.

    2013-01-01

    Two invasive, container-breeding mosquito species, Aedes aegypti (Stegomyia aegypti) and Aedes albopictus (Stegomyia albopicta) (Diptera: Culicidae), have different distribution patterns on Reunion Island. Aedes albopictus occurs in all areas and Ae. aegypti colonizes only some restricted areas already occupied by Ae. albopictus. This study investigates the abiotic and biotic ecological mechanisms that determine the distribution of Aedes species on Reunion Island. Life history traits (duratio...

  19. 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

    Science.gov (United States)

    2016-10-26

    propagation 111 Virus strains were obtained from the World Reference Center of Emerging Viruses and 112 Arboviruses Collection at the University of...probably limited emergence potential into urban 284 cycles characteristic of ZIKV, yellow fever virus , and dengue viruses . Nucleotide and 285 amino...arthropod-398 borne viruses of Tongaland. VIII. Spondweni virus , an agent previously unknown, 399 isolated from Taeniorhynchus (Mansonioides) uniformis

  20. Molecular and functional characterization of odorant-binding protein genes in an invasive vector mosquito, Aedes albopictus.

    Directory of Open Access Journals (Sweden)

    Yuhua Deng

    Full Text Available Aedes albopictus is a major vector of dengue and Chikungunya viruses. Olfaction plays a vital role in guiding mosquito behaviors and contributes to their ability to transmit pathogens. Odorant-binding proteins (OBPs are abundant in insect olfactory tissues and involved in the first step of odorant reception. While comprehensive descriptions are available of OBPs from Aedes aegypti, Culex quinquefasciatus and Anopheles gambiae, only a few genes from Ae. albopictus have been reported. In this study, twenty-one putative AalbOBP genes were cloned using their homologues in Ae. aegypti to query an Ae. albopictus partial genome sequence. Two antenna-specific OBPs, AalbOBP37 and AalbOBP39, display a remarkable similarity in their overall folding and binding pockets, according to molecular modeling. Binding affinity assays indicated that AalbOBP37 and AalbOBP39 had overlapping ligand affinities and are affected in different pH condition. Electroantennagrams (EAG and behavioral tests show that these two genes were involved in olfactory reception. An improved understanding of the Ae. albopictus OBPs is expected to contribute to the development of more efficient and environmentally-friendly mosquito control strategies.

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

    Directory of Open Access Journals (Sweden)

    Magda Clara Vieira da Costa Ribeiro

    2002-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Rahul Kumar

    2013-06-01

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

  3. Effects of agricultural pesticides on the immune system of Xenopus laevis and Rana pipiens

    Energy Technology Data Exchange (ETDEWEB)

    Christin, M.S.; Menard, L.; Gendron, A.D.; Ruby, S.; Cyr, D.; Marcogliese, D.J.; Rollins-Smith, L.; Fournier, M

    2004-03-30

    Over the last 30 years, there have been mass declines in diverse geographic locations among amp