Vector competence of Anopheles and Culex mosquitoes for Zika virus

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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.

Biological control of Anopheles darlingi, Aedes aegypti and Culex quinquefasciatus larvae using shrimps

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Willian Marinho Dourado Coelho

2017-08-01

Full Text Available Mosquitoes can act as vectors of important diseases such as malaria, dengue, Zika virus, yellow fever, Chikungunya and Mayaro fever, in addition to filariasis. The use of insecticides, larvicides, bed nets and repellents, besides the use of drugs as chemoprevention and the treatment of the sick are currently the pillars of the control of these vectors. We studied the biological control against of Anopheles darlingi, Aedes aegypti and Culex quinquefasciatus larvae using shrimps of the species M. pantanalense, M. amazonicum, M. brasiliense and M. jelskii. Larvae of mosquitoes were collected from the breeding environment and placed in a 500 and 1000 l tank containing 60 shrimps/m2. The predatory activity was evaluated for 30 days and, in all groups it was observed that 100% of the larvae were consumed in few minutes. In the environment, these same species of crustaceans were released in water bodies with the presence of larvae of these insects. In just 72 h there was a marked reduction of the larvae in the release sites of shrimps. Similarly, there was a reduction in the number of adult mosquitoes caught near the breeding sites, allowing to infer that, in places where the crustaceans were released, the predatory activity on the larvae of mosquitoes was sufficient to reduce the number of adult mosquitoes p ≤ 0,05. This is the first description of the predatory activity of M. pantanalense, M. amazonicum, M. brasiliense and M. jelskii on An. darlingi, A. aegypti and C. quinquefasciatus larvae, constituting an important tool of biological control of these parasites-vectors.

Male and mosquito larvae survey at the Arenal-Tempisque irrigation project, Guanacaste, Costa Rica

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Mario Vargas V

2003-09-01

Full Text Available A monitoring of male and larvae of mosquitoes was conducted during 1991-1994, at the Irrigation Project in Arenal-Tempisque, Guanacaste, Costa Rica. CDC CO2 -baited traps were used to collect adults of mosquitoes and dips were used for immatures of culicids. A total of 1 480 larvae and 1 129 males of culicids were identified resulting in, Aedes with 6 species, Anopheles, Mansonia and Psorophora with 2 species, Culex with 21 species and Haemagogus, Limatus, Toxorhynchites and Uranotaenia with only one species each. The results indicate that, as occurred in other countries, irrigation projects must be under strict monitoring programs to prevent and control possible health problems in which mosquitoes act as vectorsSe realizó un monitoreo de machos y larvas de mosquitos durante los años 1991 a 1994 en el Proyecto de Riego Arenal-Tempisque, Guanacaste, Costa Rica. Los especímenes fueron colectados en 32 giras de cuatro días cada una y cada 15 días. La colecta de adultos se hizo mediante trampas tipo CDC y la de larvas con la técnica estándar del cucharón. Se identificaron un total de 1 480 larvas y 1 129 machos de culícidos, correspondientes a 21 especies de Culex, 6 especies de Aedes, 2 especies de Anopheles, Mansonia, y Psorophora y una especie de Haemagogus, Limatus, Toxorhynchites y Uranotaenia. Los resultados indican que tal y como ha ocurrido en proyectos de riego en otros países, se deben mantener estrictos programas de monitoreo con el fin de prevenir y controlar posibles problemas de salud humana y animal, en los cuales los mosquitos actúen como vectores

Investigation of Bacillus thuringiensis var. israelensis (Bti endotoxin production and analysis of efficiency of Bti against mosquito larvae

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RASHMI GWAL

2015-04-01

Full Text Available Mosquitoes are dangerous to mankind and are threatening human life worldwide. Insect specific toxins, which are commonly produced by Bti, are becoming an important component of biological strategies to control mosquito's population that causes communicable or life threatening diseases. These insect specific toxins are commonly known as biolarvicides. Biolarvicides of strain Bti are highly effective against mosquito's larvae at very low doses and show no harmful effects to other non-target organisms. Therefore, Bti has been extensively used in mosquito control programs. No field resistance has been observed in mosquitoes populations treated with Bti. This suggests that Bti will be an effective biocontrol agent for years. In the present study, we evaluated the efficacy of Bti against mosquito larvae (Culex quinquefasciatus commonly found in central India, Bhopal, Madhya Pradesh. The formulation was effective in killing mosquito larvae and its international toxic unit was found to be 5200 ITU/mg.

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.

Abrigos de mosquitos Culex (Culex em zona rural (Diptera: Culicidae Resting places of mosquitoes Culex (Culex in rural zones (Diptera: Culicidae

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Almério de Castro Gomes

1990-10-01

Full Text Available As atividades antrópicas levadas a cabo em zona rural têm afetado o comportamento de mosquitos Culex (Culex, motivo pelo qual foi realizada investigação para observar seus abrigos naturais em área de pastagem, margem e interior de matas primitivas ou residuais. Foram escolhidas três localidades com características mesológicas diferenciadas pelo tipo de atividade humana, todas situadas na região do Vale do Ribeira, Estado de São Paulo, Brasil. As espécies mais abundantes foram Cx. mollis (28,0%, Cx. declarator (25,0%, Cx. lygrus (13,0% e Cx. coronator (9,6%. O conjunto Cx. Bidens + Cx. dolosus + Cx. chidesteri, de hábito mais urbanizado, foi capturado em número muito reduzido. Com relação aos ambientes pesquisados, a mata contribuiu com 2.281 indivíduos (71,4%, sugerindo ser local de abrigo preferido pelo grupo, exceto para Cx. quinquefasciatus. Avaliou-se o potencial de domiciliação de cada espécie e suas conseqüências para a população humana.The human activities carried out in rural zones have been affeecting the behavior of mosquitoes of the Culex (Culex subgenera, which was the reason for undertaking this investigation with a view to registering data on the natural resting places in pastures and on the edge of or within primitive and residual forest areas. Three localities with different mesological conditions, as to type of human activity, all them situated in the Ribeira Valley region of S. Paulo State, Brazil, were chosen. The species most abundantly found were Cx. mollis (28.0%, Cx. declarator (25.0%, Cx. lygrus (13.0% and Cx. coronator (9.6%. The collection of mosquitoes Cx. bidens + Cx. dolosus + Cx. chidesteri, known to be more urban, was much smaller than that of any other species of the group. With reference to outdoor environments, woodland contributed with 2,281 individuals (71.4% suggesting their preference for this resting place, except for Cx. quinquefasciatus. Results are evaluated for the determination

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

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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.

EFEKTIVITAS Bacillus thuringiensis H-14 STRAIN LOKAL DALAM BUAH KELAPA TERHADAP LARVA Anopheles sp dan Culex sp di KAMPUNG LAUT KABUPATEN CILACAP

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Blondine Ch. P

2013-07-01

Full Text Available Abstrak Bacillus thuringiensis serotipe H-14 strain lokal adalah bakteri patogen bersifat target spesifiknya larva nyamuk, aman bagi mamalia dan lingkungan. Penelitian bertujuan menentukan efektivitas B. thuringiensis H-14 strain lokal yang dikembangbiakkan dalam buah kelapa untuk pengendalian larva Anopheles sp dan Culex sp. Rancangan eksperimental semu, terdiri dari kelompok perlakuan dan kontrol. Bacillus thuringiensis H-14 strain lokal dikembangbiakan dalam10 buah kelapa umur 6–8 bulan, dengan berat kira-kira 1 kg, telah berisi air kelapa sekitar 400-500 ml/buah kelapa yang diperoleh dari Desa Klaces, Kampung Laut, Kabupaten Cilacap. Diinkubasi selama 14 hari pada temperatur kamar dan ditebarkan di 6 kolam yang menjadi habitat perkembangbiakan larva nyamuk dengan luas berkisar 3–100 m2.Hasil yang diperoleh menunjukkan efektivitas B. thuringiensis H-14 strain lokal terhadap larva Anopheles sp dan Culex sp selama 1 hari sesudah penebaran kematian larva berturut-turut sebesar 80–100% dan 79,31–100%. Sedangkan pada hari ke-14 sebesar 69,30–76,71% dan 67,69–86,04%. Buah kelapa dapat digunakan sebagai media lokal alternatif untuk pengembangbiakan B. thuringiensis H-14 strain lokal Kata kunci: B. thuringiensis H-14,  strain  lokal, buah kelapa, pengendalian larva Abstract Bacillus thuringiensis serotype H-14 local strain is pathogenic bacteria which specific  target to mosquito larvae. It is safe for mammals and enviroment. The aims of this study was to determine the effectivity of B. thuringiensis H-14 local strain which culturing in thecoconut wates against Anopheles sp and Culex sp mosquito larvae. This research is quasi experiment which consist of treated  and control groups. Bacillus thuringiensis H-14 local strain was cultured in 10 coconuts with 6–8 months age with weight around 1 kg that contained were approximately 400-500 ml/coconut were taken from Klaces village, Kampung Laut. After that the coconuts incubated for 14

Mosquitoes of the rice agroecosystem of Malaysia: species composition and their abundance in relation to rice farming

International Nuclear Information System (INIS)

Abu Hassan Ahmad; Che Salmah Md Rawi

2002-01-01

Mosquito abundance in relation to rice farming was studied in the Muda and the Kerian Irrigation Schemes. Mosquito larvae were collected using dippers for several growing seasons. Adult mosquitoes were collected by using human bait and cow bait and net trap at nights. Culex, Mansonia and Anopheles were the three genera of mosquito found in the rice agroecosystem. Four species of Mansonia were found biting on human bait. Culex mosquitoes were caught biting on human and cow baits. Culex tritaeniorhynchus, C pseudovishnui, C vishnui, C gelidus and C bitaeniorhynchus were the most common Culex mosquitoes found. Anoheles sinensis and A. peditaeniatus were the most dominant panopheline mosquitoes. High abundance of larvae and adult mosquitoes were observed during ploughing, planting, and tillering stages of rice farming. (Author)

Mosquito larvicidal and ovicidal properties of Pithecellobium dulce (Roxb.) Benth. (Fabaceae) against Culex quinquefasciatus Say (Diptera: Culicidae)

OpenAIRE

Govindarajan Marimuthu; Rajeswary Mohan

2014-01-01

Objective: To assess the larvicidal and ovicidal potential of the crude hexane, benzene, chloroform, ethyl acetate and methanol solvent extracts from the medicinal plant, Pithecellobium dulce (P. dulce) against filariasis vector mosquito, Culex quinquefasciatus (Cx. quinquefasciatus). Methods: Twenty five early third instar larvae of Cx. quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using the protocol of WHO (2005). The larval mor...

Bacterial communities associated with culex mosquito larvae and two emergent aquatic plants of bioremediation importance.

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Dagne Duguma

Full Text Available Microbes are important for mosquito nutrition, growth, reproduction and control. In this study, we examined bacterial communities associated with larval mosquitoes and their habitats. Specifically, we characterized bacterial communities associated with late larval instars of the western encephalitis mosquito (Culextarsalis, the submerged portions of two emergent macrophytes (California bulrush, Schoenoplectuscalifornicus and alkali bulrush, Schoenoplectusmaritimus, and the associated water columns to investigate potential differential use of resources by mosquitoes in different wetland habitats. Using next-generation sequence data from 16S rRNA gene hypervariable regions, the alpha diversity of mosquito gut microbial communities did not differ between pond mesocosms containing distinct monotypic plants. Proteobacteria, dominated by the genus Thorsellia (Enterobacteriaceae, was the most abundant phylum recovered from C. tarsalis larvae. Approximately 49% of bacterial OTUs found in larval mosquitoes were identical to OTUs recovered from the water column and submerged portions of the two bulrushes. Plant and water samples were similar to one another, both being dominated by Actinobacteria, Bacteroidetes, Cyanobacteria, Proteobacteria and Verrucomicrobia phyla. Overall, the bacterial communities within C. tarsalis larvae were conserved and did not change across sampling dates and between two distinct plant habitats. Although Thorsellia spp. dominated mosquito gut communities, overlap of mosquito gut, plant and water-column OTUs likely reveal the effects of larval feeding. Future research will investigate the role of the key indicator groups of bacteria across the different developmental stages of this mosquito species.

Importance of waste stabilization ponds and wastewater irrigation in the generation of vector mosquitoes in Pakistan

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Mukhtar, Muhammad; Ensink, Jeroen; Van der Hoek, Wim

2006-01-01

The objective of the current study was to investigate the role of waste stabilization ponds (WSP) and wastewater-irrigated sites for the production of mosquitoes of medical importance. Mosquito larvae were collected fortnightly from July 2001 to June 2002 in Faisalabad, Pakistan. In total, 3......,132 water samples from WSP and irrigated areas yielded 606,053 Culex larvae of five species. In addition, 107,113 anophelines, representing eight species were collected. Anopheles subpictus (Grassi) and Culex mosquitoes, especially Culex quinquefasciatus (Say) and Culex tritaeniorhynchus (Giles), showed...... an overwhelming preference for anaerobic ponds, which receive untreated wastewater. Facultative ponds generated lower numbers of both Anopheles and Culex mosquitoes, whereas the last ponds in the series, the maturation ponds, were the least productive for both mosquito genera. An. subpictus and Anopheles...

Comparative efficacy and pathogenicity of keratinophilic soil fungi against Culex quinquefasciatus larvae.

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Mohanty, Suman Sundar; Prakash, Soam

2010-09-01

Out of seven fungal species belonging to four genera isolated from pond and wallow soils using feathers of Pavo cristatus as bait, four species viz., Aspergillus flavus, Aspergillus niger, Chrysosporium pseudomerdarium and Trichophyton ajelloi were most frequent. Chrysosporium and Trichophyton spp. were more pathogenic on Culex quinquefasciatus larvae than Aspergillus and Penicillium. The bioefficacy tests conducted as per the protocol of World Health Organization and the LC(50) values calculated by the Probit analysis showed that 3(rd)-instar C. quinquefasciatus were more susceptible to the conidia of above fungi. Highest mortality was observed in the larvae of C. quinquefasciatus when exposed to T. ajelloi. The density of fungal conidia was greatest on the ventral brush, palmate hair and anal region of the mosquito larvae after exposing for 72 hours. The potentiality of these fungi for use in the control of C. quinquefasciatus is discussed which can be exploited as a suitable biocontrol agent in the tropics.

Resistance Level of Mosquito Species (Diptera: Culicidae from Shandong Province, China

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Hong-Mei Liu

2015-01-01

Full Text Available This study describes the aquatic habitats, species composition, and the insecticide resistance level of the mosquito Culex pipiens pallens in Shandong Province, China. A cross-sectional survey of mosquito larval habitats was conducted from May to November 2014 to determine the species composition and larval abundance. Larvae were collected using the standard dipping technique, and a total of four habitat types were sampled. The fourth instar larvae of Cx. pipiens pallens collected in each habitat type were tested for resistance to five insecticides according to a WHO bioassay. A total of 7,281 mosquito larvae were collected, of which 399 (5.48% were categorized as Anopheles mosquito larvae ( An. sinensis , 6636 (91.14% as culicine larvae ( Cx. pipiens pallens, Cx. tritaeniorhynchus, Cx. halifaxii, and Cx. bitaeniorhynchus , 213 (2.93% as Armigeres larvae, and 33 (0.45% as Aedes larvae ( Aedes albopictus . In addition, a total of 1,149 mosquito pupae were collected. Culex larvae were distributed in all habitats investigated. Tukeys HSD analysis showed that roadside drainages were the most productive habitat type for Culex larvae. Armigeres species were found only in drains, Aedes only in water tanks, and Anopheles in water that was comparatively clear and rich in emergent plants. Bioassay showed that the maximum resistance level of Cx. pipiens pallens was to deltamethrin, while it was lowest to plifenate. The productivity of various mosquitoes in different habitat types is very heterogeneous. It is particularly important to modify human activity and the environment to achieve effective mosquito vector control. For effective larval control, the type of habitat should be considered, and the most productive habitat type should be given priority in mosquito abatement programs.

Larvacidal Effect of Imperata Cylindrical Root Decoction against Culex sp. Larvae

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Afini Tiara Resi

2014-08-01

Full Text Available Background: Filariasis is one of the neglected tropical diseases. About 337 of 401 districts in Indonesia are endemic areas for filariasis, especially in Sumatera, Kalimantan, and Papua. Culex sp. is one of the lymphatic filariasis vectors which can be controlled by insecticide, including larvacide. This study was conducted to determine the larvacidal effect of Imperata cylindrical root decoction against Culex sp. larvae. Methods: This study was conducted at the Laboratory of Parasitology, Faculty of Medicine, Universitas Padjadjaran during the period of September to November 2012. The study object was Culex sp. larvae III/IV instars. The design of this study was experimental laboratory using true experimental approach. The larvae were divided into three groups: negative control (distilled water, reference (Abate®, and decoction. The number of larvae in each group was 25 larvae, and the effects were evaluated by the total number of dead larvae in 48 hours under observation. The data were then analyzed by Mann-Whitney test and Probit test. Results: The result of the Mann-Whitney test to compare Imperata cylindrica root decoction treatment to distilled water as control was significant (p<0.05. However, Abate® gave a better result. The Probit test resultwas LC50: 63% and LC90: 489%. Conclusions: Imperata cylindrical root decoction has a larvacidal effect against Culex sp. larvae.

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-Badillo, Alvaro; Bolling, Bethany G; Perez-Ramirez, Gerardo; Moore, Chester G; Martinez-Munoz, Jorge P; Padilla-Viveros, America A; Camacho-Nuez, Minerva; Diaz-Perez, Alfonso; Beaty, Barry J; Munoz, Maria de Lourdes

2011-05-09

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

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

Efectividad y supervivencia de Romanomermis culicivorax en criaderos naturales de larvas de mosquitos

OpenAIRE

Pérez-Pacheco, Rafael; Santamarina-Mijares, Alberto; Vásquez-López, Alfonso; Martínez-Tomás, Sabino H.; Suárez-Espinosa, Javier

2009-01-01

Los mosquitos (Díptera: Culicidae) son transmisores de agentes causales de paludismo, dengue y encefalitis del Nilo occidental y causan fuertes molestias a los humanos. El objetivo del presente estudio fue determinar el efecto de aplicar 500 y 1000 nemátodos, Romanomermis culicivorax Ross y Smith, por metro cuadrado en poblaciones de larvas de Anopheles albimanus Wiedeman, Culex nigipalpus Theobald y Uranotaenia sapphirina Oster-Sacken, para su control en 13 criaderos naturales. El diseño exp...

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

Science.gov (United States)

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

2013-12-01

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

Avian phenotypic traits related to feeding preferences in two Culex mosquitoes

Science.gov (United States)

Yan, Jiayue; Gangoso, Laura; Martínez-de la Puente, Josué; Soriguer, Ramón; Figuerola, Jordi

2017-10-01

Host choice by mosquitoes affects the transmission dynamics of vector-borne infectious diseases. Although asymmetries in mosquito attraction to vertebrate species have been reported, the relative importance of host characteristics in mosquito blood-feeding behavior is still poorly studied. Here, we investigate the relationship between avian phenotypic traits—in particular, morphometry, plumage coloration, and nesting and roosting behavior—and the blood-feeding patterns in two common Culex mosquito species on a North American avian community. Forage ratios of the mosquito species were unrelated to the phylogenetic relationships among bird species. Culex pipiens fed preferably on birds with lighter-colored plumage and longer tarsi; furthermore, solitary roosting avian species were both bitten by Cx. pipiens and Cx. restuans more often than expected. These associations may be explained by greater mosquito attraction towards larger birds with a greater color contrast against the background. Although communally roosting birds may release more cues and attract more mosquitoes, individuals may in fact receive fewer bites due to the encounter-dilution effect. Mosquito feeding behavior is a highly complex phenomenon, and our results may improve understanding of the non-random interaction between birds and mosquitoes in natural communities.

Monthly prevalence and diversity of mosquitoes (Diptera: Culicidae in Fars Province, Southern Iran

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Davood Keshavarzi

2017-02-01

Full Text Available Objective: To get new data about the ecology of mosquitoes, which would be valuable to develop programs for future provision of mosquito controls in the study area. Methods: During April to September 2012, larvae of mosquitoes were collected from six counties in south of Fars Province using dipping method. Characteristics of larval breeding places were considered based on water conditions. Species diversity was examined in terms of alpha and beta measures, with the intent of comparing mosquito diversity according to the typology of regions. Results: During this investigation, totally, 5 057 larvae of mosquitoes belonging to 5 genera and 17 different mosquito species were recognized, namely, Anopheles dthali, Anopheles fluviatilis, Anopheles stephensi, Anopheles superpictus, Culex quinquefasciatus (Cx. quinquefasciatus, Culex mimeticus, Culex perexiguus, Culex pipiens (Cx. pipiens, Culex tritaeniorhynchus, Culex theileri (Cx. theileri, Culex tritaeniorhynchus, Culex sinaiticus, Culex torrentium, Culex modestus, Ochlerotatus caspius, Culiseta longiareolata and Aedes vexans (Ae. vexans. This is the first record of Ae. vexans, Culex perexiguus and Culex modestus in the Province. Cx. pipiens (27.3%, Cx. theileri (15.9% and Cx. quinquefasciatus (9.4% were the most abundant species found respectively. Cx. pipiens reached the highest density in August and July, while Cx. theileri, Cx. quinquefasciatus and Ae. vexans were found in high numbers in June. Diversity analysis indicated the highest species diversity in the Mohr County (Margalef index of 1.41 and Shannon index of 1.7 and the lowest species diversity in the Lamerd County (Margalef index of 0.33 and Shannon index of 0.38. Conclusions: Regarding to this research, there are some potential vectors of medical and veterinary importance in Fars Province. Results of the present study may serve as a basis for risk assessment of emerging mosquito-borne diseases.

Genome analysis of cytochrome P450s and their expression profiles in insecticide resistant mosquitoes, Culex quinquefasciatus.

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Ting Yang

Full Text Available Here we report a study of the 204 P450 genes in the whole genome sequence of larvae and adult Culex quinquefasciatus mosquitoes. The expression profiles of the P450 genes were compared for susceptible (S-Lab and resistant mosquito populations, two different field populations of mosquitoes (HAmCq and MAmCq, and field parental mosquitoes (HAmCq(G0 and MAmCq(G0 and their permethrin selected offspring (HAmCq(G8 and MAmCq(G6. While the majority of the P450 genes were expressed at a similar level between the field parental strains and their permethrin selected offspring, an up- or down-regulation feature in the P450 gene expression was observed following permethrin selection. Compared to their parental strains and the susceptible S-Lab strain, HAmCq(G8 and MAmCq(G6 were found to up-regulate 11 and 6% of total P450 genes in larvae and 7 and 4% in adults, respectively, while 5 and 11% were down-regulated in larvae and 4 and 2% in adults. Although the majority of these up- and down-regulated P450 genes appeared to be developmentally controlled, a few were either up- or down-regulated in both the larvae and adult stages. Interestingly, a different gene set was found to be up- or down-regulated in the HAmCq(G8 and MAmCq(G6 mosquito populations in response to insecticide selection. Several genes were identified as being up- or down-regulated in either the larvae or adults for both HAmCq(G8 and MAmCq(G6; of these, CYP6AA7 and CYP4C52v1 were up-regulated and CYP6BY3 was down-regulated across the life stages and populations of mosquitoes, suggesting a link with the permethrin selection in these mosquitoes. Taken together, the findings from this study indicate that not only are multiple P450 genes involved in insecticide resistance but up- or down-regulation of P450 genes may also be co-responsible for detoxification of insecticides, insecticide selection, and the homeostatic response of mosquitoes to changes in cellular environment.

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

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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.

Essential Oils of Satureja Species: Insecticidal Effect on Culex pipiens Larvae (Diptera: Culicidae

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Nikos G. Chorianopoulos

2007-12-01

Full Text Available The chemical composition of the essential oils of the wild growing plants of Greek S. spinosa L., S. parnassica subsp. parnassica Heldr.& Sart ex Boiss., S. thymbra and S. montana were determined by GC and GC/MS analysis. The larvicidal activities of the essential oils were assayed against Culex pipiens biotype molestus. The analytical data indicated that various monoterpene hydrocarbons and phenolic monoterpenes constitute the major constituents of the oils, but their concentration varied greatly among the oils examined. The bioassay results indicated that the oils possess significant larvicidal activities and represent an inexpensive source of natural substances mixture that exhibit potentials for use to control the mosquito larvae.

"Bird biting" mosquitoes and human disease: a review of the role of Culex pipiens complex mosquitoes in epidemiology.

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

2011-10-01

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 that are fed on. One group of vectors, the mosquitoes in the Culex pipiens complex, play key roles in the transmission of a range of pathogens including several viruses such as West Nile and St. Louis encephalitis viruses, avian malaria (Plasmodium spp.), and filarial worms. The Cx. pipiens complex includes Culex pipiens pipiens with two forms, pipiens and molestus, Culex pipiens pallens, Culex quinquefasciatus, Culex australicus, and Culex globocoxitus. While several members of the complex have limited geographic distributions, Cx. pipienspipiens and Cx. quinquefasciatus are found in all known urban and sub-urban temperate and tropical regions, respectively, across the world, where they are often principal disease vectors. In addition, hybrids are common in areas of overlap. Although gaps in our knowledge still remain, the advent of genetic tools has greatly enhanced our understanding of the history of speciation, domestication, dispersal, and hybridization. We review the taxonomy, genetics, evolution, behavior, and ecology of members of the Cx. pipiens complex and their role in the transmission of medically important pathogens. The adaptation of Cx. pipiens complex mosquitoes to human-altered environments led to their global distribution through dispersal via humans and, combined with their mixed feeding patterns on birds and mammals (including humans), increased the transmission of several avian pathogens to humans. We highlight several unanswered questions that will increase our ability to control diseases transmitted by these mosquitoes. Copyright © 2011 Elsevier B.V. All rights reserved.

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

ISOLASI BACILLUS THURINGIENSIS DARI LARVA DAN PENGUJIAN PATOGENISITASNYA TERHADAP LARVA NYAMUK VEKTOR

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Blondine Ch. P.

2012-09-01

Full Text Available A study to evaluate pathogenic organisms as cause of mosquito larvae death was conducted at Wonokerto and Pabelan villages, Salatiga Luar Kota subdistrict, Semarang regency in Central Java from May 1991 through December 1991. Bacterial isolation from dead larvae showed that 31 B. thuringicnsis isolates were obtained from 31 larvae samples collected from 2 location e.g Wonokerto village (3 samples, Pabelan village (28 samples. Nineteen isolates (61,3% showed a pathogenicity of more than 50% to third toward instar larvae of Aedes aegypti and Culex quinquefasciatus respectively 24 hours after exposure. This study shows the possible use of B. thuringiensis for biologic control of mosquitoes which can act as vectors for human diseases.

Species\\' identification of Anopheles and Culex mosquitoes and its ...

African Journals Online (AJOL)

Indoor and outdoor bites' collections of gravid Anopheles and Culex mosquitoes were made with plastic aspirator from residential areas within Jimeta-Yola metropolis for three years (between March and May; August and October 2003 to 2005). They were identified using standard morphological keys and polymerase chain ...

Efficacy of Bacillus thuringiensis var israelinsis (Bti) on Culex and ...

African Journals Online (AJOL)

dosage that can be used to control Culex mosquito larvae in Zomba after ... exposed to the same dosage of liquid formulation of Bti (0.001ml/L) there ... The objective of this study was to evaluate the efficacy of Bti on mosquito ...... In short Bti whether liquid or granular is very important as it significantly reduces the densities of ...

Olfactory memory in the mosquito Culex quinquefasciatus.

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McCall, P J; Eaton, G

2001-06-01

The cosmotropical urban mosquito Culex quinquefasciatus Say (Diptera: Culicidae) uses chemical cues to locate suitable water pools for oviposition. Although gravid females are innately attracted to or repelled by certain compounds, this study found that an individual mosquito's preferences for these odours could be altered greatly by prior experience. Mosquitoes reared in water containing skatole, at a level normally repellent to ovipositing females, preferred to oviposit in water containing that compound rather than in water with an otherwise attractive odour compound (P-cresol). This behaviour occurred regardless of whether mosquitoes were tested individually or in groups of up to 50 per cage. The F1 progeny of conditioned mosquitoes did not exhibit the parental preference, but were as susceptible to conditioning as their parents. Moreover, rearing mosquitoes in infusions of hay or animal (guinea-pig) faeces produced a similar although less dramatic change, such that the innate propensity for hay infusion could be cancelled by rearing in guinea-pig faeces infusion. The results demonstrated a change in odour preference by Cx. quinquefasciatus following exposure to the odour during development or pupal eclosion, suggesting that some form of larval conditioning or early adult imprinting occurred. Precisely when that conditioning occurred remains to be determined.

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.

Influence of Hepatozoon parasites on host-seeking and host-choice behaviour of the mosquitoes Culex territans and Culex pipiens.

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Ferguson, Laura V; Kirk Hillier, N; Smith, Todd G

2013-12-01

Hepatozoon species are heteroxenous parasites that commonly infect the blood of vertebrates and various organs of arthropods. Despite their ubiquity, little is known about how these parasites affect host phenotype, including whether or not these parasites induce changes in hosts to increase transmission success. The objectives of this research were to investigate influences of the frog blood parasite Hepatozoon clamatae and the snake blood parasite Hepatozoon sipedon on host-seeking and host-choice behaviour of the mosquitoes Culex territans and Culex pipiens, respectively. During development of H. sipedon in C. pipiens, significantly fewer infected mosquitoes fed on uninfected snakes compared to uninfected mosquitoes. When H. sipedon was mature in C. pipiens, the number of infected and uninfected C. pipiens that fed on snakes was not significantly different. Higher numbers of mosquitoes fed on naturally infected snakes and frogs compared to laboratory-reared, uninfected control animals. However, experiments using only laboratory-raised frogs revealed that infection did not significantly affect host choice by C. territans. Behaviour of C. pipiens in the presence of H. sipedon may increase transmission success of the parasite and provide the first evidence of phenotypic changes in the invertebrate host of Hepatozoon parasites.

Influence of Hepatozoon parasites on host-seeking and host-choice behaviour of the mosquitoes Culex territans and Culex pipiens☆

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Ferguson, Laura V.; Kirk Hillier, N.; Smith, Todd G.

2012-01-01

Hepatozoon species are heteroxenous parasites that commonly infect the blood of vertebrates and various organs of arthropods. Despite their ubiquity, little is known about how these parasites affect host phenotype, including whether or not these parasites induce changes in hosts to increase transmission success. The objectives of this research were to investigate influences of the frog blood parasite Hepatozoon clamatae and the snake blood parasite Hepatozoon sipedon on host-seeking and host-choice behaviour of the mosquitoes Culex territans and Culex pipiens, respectively. During development of H. sipedon in C. pipiens, significantly fewer infected mosquitoes fed on uninfected snakes compared to uninfected mosquitoes. When H. sipedon was mature in C. pipiens, the number of infected and uninfected C. pipiens that fed on snakes was not significantly different. Higher numbers of mosquitoes fed on naturally infected snakes and frogs compared to laboratory-reared, uninfected control animals. However, experiments using only laboratory-raised frogs revealed that infection did not significantly affect host choice by C. territans. Behaviour of C. pipiens in the presence of H. sipedon may increase transmission success of the parasite and provide the first evidence of phenotypic changes in the invertebrate host of Hepatozoon parasites. PMID:24533317

Diversity of mosquitoes and larval breeding preference based on physico-chemical parameters in Western Ghats, Tamilnadu, India

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Periyasamy Senthamarai Selvan

2015-06-01

Full Text Available Objective: To study the diversity and distribution of mosquitoes in Western Ghats of Coimbatore and Nilgiris District, Tamilnadu, India. Methods: Random collections were carried out during August-2013 to July-2014 in cesspits, animal footprints, rock holes, tree holes, drainages at study areas of Marudhamalai, Valparai, Mettupalayam in Coimbatore District and Dhottapeta, Coonoor, Gudalur in Nilgiris District of Tamilnadu, India by using suction tube and kerosene pump. Mosquitoes were identified by standard entomological procedures. Results: A total of 1 018 mosquitoes (larvae and pupae were collected from all over the study areas comprising 6 genera and 23 species. They are, Culex mimulus, Culex pseudovishnui, Culex quinquefasciatus, Culex vishnui, Culex khazani, Culex uniformis, Heizmannia chandi, Heizmannia grenii, Heizmannia indica, Oclerotatus anureostriatus, Oclerotatus albotaeniatis, Oclerotatus deccanus, Oclerotatus gubernatoris, Aedes aegypti, Aedes albopictus, Aedes edwardsi, Aedes krombeini, Toxorhynchites minimus, Toxorhynchites splendens, Anopheles aitkenii, Anopheles barbirostris, Anopheles culiciformis and Anopheles maculatus. ShannonWeaver diversity index, Margalef’s index of richness and Simpsons dominance index was also studied. From 6 sites, the highest mosquitoes were collected from Marudhamalai (309 and the least mosquitoes were collected in Mettupalayam (68. The study determined whether physicochemical characteristics differ between habitats with high and low presence of mosquito larvae. Based on Margalef’s index of richness (Dmg, the highest values were present in Mettupalayam (5.214 study area and the lowest in Marudhamalai (3.837. It can be concluded from Shanon-Weaver index of diversity that, the highest values were present in Mettupalayam (2.947 and the least value were in Gudalur (2.410 during the study period. Conclusions: In areas with reservoirs of disease, mosquito abundance information can help to identify the

Additional records of vector mosquito diversity collected from Al Khor district of North-eastern Qatar

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Mahmoud Mohammed Kardousha

2015-10-01

Full Text Available Objective: To survey mosquito diversity in the north-eastern area, which includes the most important gas industrial city in Qatar, and to investigate the potential mosquitoes for transmitting diseases. Methods: A study was performed from September 2009 until June 2011 in Al-Khor district of North-eastern Qatar. Five localities were selected for larval collection: Al Khor City (the main city, Al Dhakira, Ras Laffan (gas industrial city, Simsimah and Al Ghuwariyah. The survey was carried out by using different sampling methods and covering all expected natural breeding sites. The larvae were collected, preserved and transferred to the laboratory for identification. Results: Our findings revealed that 10 species of mosquito larvae had been detected from the area and five of them were new records in Qatar. The species encountered were: Ochlerotatus caspius (Pallas 1771, Anopheles stephensi (Liston 1901, Culex quinquefasciatus (Say 1823 (Cx. quinquefasciatus, Culex pipiens biotype molestus (Forskal 1775 (Cx. pipiens, Culex univittatus (Theobald 1901, Culex pusillus (Macquart 1850, Culex tritaeniorhynchus (Giles 1901 (Cx. tritaeniorhynchus, Culex laticinctus (Edwards 1913, Culex sitiens (Weidmann 1828 and Culex perexiguus (Theobald 1901. The new recorded species were Cx. quinquefasciatus, Cx. tritaeniorhynchus, Culex laticinctus, Culex sitiens and Culex perexiguus. The most prevalent type was Cx. pipiens molestus (31.29% and followed by Culex pusillus and Cx. quinquefasciatus which have relatively similar prevalence of 18.72% and 18.52% respectively. Anopheles stephensi was an established vector for malaria. Cx. pipiens molestus and Cx. quinquefasciatus were vectors of West Nile virus and filariasis. Cx. tritaeniorhynchus was established as a vector of Rift Valley virus and Culex univittatus was the main vector of Sindbis virus. Conclusions: The north-eastern area of Qatar harbors is the most important industrial city in the country, which has

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

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

2009-12-01

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

Seasonal and Topographical Factors Affecting Breeding Sites of Culex Larvae in Nakhon Si Thammarat, Thailand

OpenAIRE

Warabhorn PREECHAPORN; Mullica JAROENSUTASINEE; Krisanadej JAROENSUTASINEE; Jirawat SAETON

2007-01-01

This study investigated how the seasons affect the key breeding sites of Culex larvae in three topographical areas: mangrove, rice paddy and mountainous areas. We examined how the number of Culex larvae varied in different types of water containers. Water containers were categorised into the following groups: indoor/outdoor containers, artificial/natural containers, earthen/plastic containers, containers with/without lids and dark/light coloured containers. Samples were collected from 300 hou...

Development of lymphatic filarial parasite Wuchereria bancrofti (Spirurida: Onchocercidae) in mosquito species (Diptera: Culicidae) fed artificially on microfilaremic blood.

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Paily, K P; Hoti, S L; Balaraman, K

2006-11-01

The efficiency of laboratory colonies of mosquitoes such as Anopheles stephensi Liston, Aedes aegypti (L.) Liverpool strain, Ae. aegypti wild type, Aedes albopictus (Skuse), Culex tritaeniorhynchus Giles, Culex sitiens Wiedemann, and Armigeres subalbatus Coquillett in supporting the development of Wuchereria bancrofti (Cobbold) (Spirurida: Onchocercidae) microfilariae to infective larvae was investigated. The mosquitoes were fed on heparinized microfilaremic human blood by using a membrane-feeding unit with Parafilm as membrane. The rate of infection, parasite development, and parasite burden were compared with that in the known vector mosquito Culex quinquefasciatus Say. Cx. quinquefasciatus showed the highest percentage of infection, followed by Ae. aegypti Liverpool strain and An. stephensi. The rate of development of the parasite was more or less similar in all the three species, and infective larvae were found on day 13. When the larvae were harvested on day 17, Cx. quinquefasciatus yielded the highest numbers, followed by Ae. aegypti Liverpool strain and An. stephensi. The percentage of infection was low, and the development was slow in Cx. tritaeniorhynchus compared with the other susceptible species. The parasite developed to second-stage larvae only by day 22 and to infective larvae by day 28. When 2-wk-old Cx. tritaeniorhynchus were fed on microfilaremic blood, they could develop the parasite to infective larvae by day 13 postfeeding. All other species of mosquitoes tested were found to be refractory to parasite development. It is shown that Cx. quinquefasciatus is the most suitable mosquito host for the production of infective larvae. However, Ae. aegypti Liverpool strain, which is commonly used for Brugia malayi filarial parasite, also can be used for generation of W. bancrofti infective larvae to circumvent the problem of maintaining two mosquito species.

Mosquito larvicidal and ovicidal properties of Pithecellobium dulce (Roxb. Benth. (Fabaceae against Culex quinquefasciatus Say (Diptera: Culicidae

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Govindarajan Marimuthu

2014-04-01

Full Text Available Objective: To assess the larvicidal and ovicidal potential of the crude hexane, benzene, chloroform, ethyl acetate and methanol solvent extracts from the medicinal plant, Pithecellobium dulce (P. dulce against filariasis vector mosquito, Culex quinquefasciatus (Cx. quinquefasciatus. Methods: Twenty five early third instar larvae of Cx. quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using the protocol of WHO (2005. The larval mortality was observed after 24 h of treatment. The ovicidal activity was determined against Cx. quinquefasciatus mosquito eggs to various concentrations ranging from 100-750 mg/L under the laboratory conditions. Results: The methanol extract of the leaves and seed of P. dulce was the most effective against the larvae with LC 50 and LC90 values 164.12 mg/L, 214.29 mg/L, 289.34 mg/L and 410.18 mg/L being observed after 24 h of exposure. The efficacy of methanol was followed by that of the ethyl acetate, chloroform, benzene and hexane extracts. The mean percent hatchability of the egg rafts were observed after 48 h of treatment. About 100% mortality was observed at 500 mg/L for leaf and 750 mg/L for seed methanol extracts of P. dulce. Conclusions: From the results, it can be concluded that the larvicidal and ovicidal effect of P. dulce against Cx. quinquefasciatus make this plant product promising as an alternative to synthetic insecticide in mosquito control programs.

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

Science.gov (United States)

Das, Dipanwita; Chandra, Goutam

2012-01-01

To establish the larvicidal activities, if any of solvent extracts of Rauvolfia serpentina (R. serpentina) L. seeds against Culex quinquefasciatus (Cx. quinquefasciatus) Say, 1823 as target species. Seeds of R. serpentina were extracted with five solvents graded according to the polarity [viz. petroleum ether, benzene, ethyl acetate, acetone and absolute alcohol] continuing one after another with the same seeds. Mortality rate with petroleum ether extract was significantly higher than other extracts. The mortality rates of late 3rd instar larvae were 50.33±5.51, 10.00±1.00, 0.00±0.00, 21.33±1.53 and 0.00±0.00 in 100 ppm concentration of petroleum ether, benzene, ethyl acetate, acetone and absolute alcohol respectively, after 24 h of exposure period. Results of this study show that petroleum ether extract of R. serpentina seed may be considered as a potent source of mosquito larvicidal agent. Copyright © 2012 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Pengaruh ukuran tubuh ikan Poecilia reticulata pada daya pemangsaannya terhadap larva Culex quinquefasciatus

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Noer Moehammadi

1999-06-01

Full Text Available The research aimed to know the influence of poecilia reticulata body size, in the feeding capacity on Culex quinquifasciatus larvae. The research was experimental method with Complete Random Design., each treatment with 5 replications. The taken body size of Poecilia reticulata were; 1,50 cm; 2.50 cm; and 3.50 cm. the size of fish €™s body was measured from the tip of snout up to the end of fin (cm. The feeding capacity was determined by subtracting the first amount of larvae which was given the rest of larvae after 24 hours. The result showed that the difference of size of Poecilia reticulate body was significantly different in the feeding capacity on Culex quinquifasciatus larvae. The fish whose body size was 1.50 cm had the lowest feeding capacity by eating 77.2 larvae for average, and the highest one was the fist which body size was 2.50 cm by eating 113.6 larvae for average, subsequently the feeding capacity decrease to the fish which body size was 3.50 cm because of eating 100,6 larvae for 24 hours.

Multiple Cytochrome P450 genes: their constitutive overexpression and permethrin induction in insecticide resistant mosquitoes, Culex quinquefasciatus.

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Liu, Nannan; Li, Ting; Reid, William R; Yang, Ting; Zhang, Lee

2011-01-01

Four cytochrome P450 cDNAs, CYP6AA7, CYP9J40, CYP9J34, and CYP9M10, were isolated from mosquitoes, Culex quinquefasciatus. The P450 gene expression and induction by permethrin were compared for three different mosquito populations bearing different resistance phenotypes, ranging from susceptible (S-Lab), through intermediate (HAmCq(G0), the field parental population) to highly resistant (HAmCq(G8), the 8(th) generation of permethrin selected offspring of HAmCq(G0)). A strong correlation was found for P450 gene expression with the levels of resistance and following permethrin selection at the larval stage of mosquitoes, with the highest expression levels identified in HAmCq(G8), suggesting the importance of CYP6AA7, CYP9J40, CYP9J34, and CYP9M10 in the permethrin resistance of larva mosquitoes. Only CYP6AA7 showed a significant overexpression in HAmCq(G8) adult mosquitoes. Other P450 genes had similar expression levels among the mosquito populations tested, suggesting different P450 genes may be involved in the response to insecticide pressure in different developmental stages. The expression of CYP6AA7, CYP9J34, and CYP9M10 was further induced by permethrin in resistant mosquitoes. Taken together, these results indicate that multiple P450 genes are up-regulated in insecticide resistant mosquitoes through both constitutive overexpression and induction mechanisms, thus increasing the overall expression levels of P450 genes.

Role of G-protein-coupled receptor-related genes in insecticide resistance of the mosquito, Culex quinquefasciatus.

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Li, Ting; Liu, Lena; Zhang, Lee; Liu, Nannan

2014-09-29

G-protein-coupled receptors regulate signal transduction pathways and play diverse and pivotal roles in the physiology of insects, however, the precise function of GPCRs in insecticide resistance remains unclear. Using quantitative RT-PCR and functional genomic methods, we, for the first time, explored the function of GPCRs and GPCR-related genes in insecticide resistance of mosquitoes, Culex quinquefasciatus. A comparison of the expression of 115 GPCR-related genes at a whole genome level between resistant and susceptible Culex mosquitoes identified one and three GPCR-related genes that were up-regulated in highly resistant Culex mosquito strains, HAmCq(G8) and MAmCq(G6), respectively. To characterize the function of these up-regulated GPCR-related genes in resistance, the up-regulated GPCR-related genes were knockdown in HAmCq(G8) and MAmCq(G6) using RNAi technique. Knockdown of these four GPCR-related genes not only decreased resistance of the mosquitoes to permethrin but also repressed the expression of four insecticide resistance-related P450 genes, suggesting the role of GPCR-related genes in resistance is involved in the regulation of resistance P450 gene expression. This results help in understanding of molecular regulation of resistance development in Cx. quinquefasciatus.

Eficiencia del extracto de Ricinus communis para el control del mosquito Culex

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Diego Tomás Corradine Mora

2014-05-01

Full Text Available Este artículo evaluó el efecto insecticida del extracto de Ricinus communis sobre larvas de mosquitos Culex. A las 24 h la mortalidad es de 8.33 % con dosis de 1 mL del extracto en una concentración de 500 ppm; 35 % en dosis de 1 mL de una concentración de 1000 ppm; 65 % en dosis de 5 mL de una concentración de 1000 ppm; 98.33 % con 10 mL en concentración de 1000 ppm; testigos 3.3 %. Cuando se evaluó el efecto insecticida del extracto aplicado por aspersión en concentraciones de 500, 750 y 1000 ppm, se consiguieron mortalidades de 18.33, 36.66 y 48.32 %, respectivamente. Ninguna de las concentraciones evaluadas alcanzó el cien por ciento de letalidad. En la prueba de semicampo, solo se logró una mortalidad de 9 %. Se evidenció que el extracto tiene un mejor efecto insecticida para el control de ejemplares inmaduros en estado larvario que sobre los adultos.

Larvicidal potential of Cyathea species against Culex quinquefasciatus

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Johnson Marimuthu alias Antonysamy

2017-05-01

Full Text Available Resistance to insecticides has persuaded researchers to find new methods to control Culex quinquefasciatus proliferation. Plants may be a source of alternative agents for mosquito control due to ever-growing insecticide resistance in mosquito vectors and environmental imbalance caused by synthetic insecticides. The present study was intended to study the larvicidal activity of selected Cyathea species against the filarial vector Culex quinquefasciatus. Larvicidal potential of different extracts were evaluated and larval mortality were recorded. The larvae were more sensitive to ethanolic extracts of studied three Cyathea species when compared to other extracts. Acetone, chloroform and petroleum ether extracts were considered to be less effective. The LC50 values of different extracts ranged from 320.72 to 657.03 µg/ml. The results exhibited that the tested three Cyathea species showed concentration dependent potential larvicidal effects and also provide an indication of possible bioactive properties.

Terrestrial vegetation and aquatic chemistry influence larval mosquito abundance in catch basins, Chicago, USA

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Gardner Allison M

2013-01-01

Full Text Available Abstract Background An important determinant of mosquito-borne pathogen transmission is the spatial distribution of vectors. The primary vectors of West Nile virus (WNV in Illinois are Culex pipiens Linnaeus (Diptera: Culicidae and Culex restuans Theobald. In urban environments, these mosquitoes commonly oviposit in roadside storm water catch basins. However, use of this habitat is inconsistent, with abundance of larvae varying significantly across catch basins at a fine spatial scale. Methods We tested the hypothesis that attributes of the biotic and abiotic environment contribute to spatial and temporal variation in production of mosquito vectors, characterizing the relationship between terrestrial vegetation and aquatic chemistry and Culex abundance in Chicago, Illinois. Larvae were sampled from 60 catch basins from June 14 to October 3, 2009. Density of shrubs and 14 tree genera surrounding the basins were quantified, as well as aquatic chemistry content of each basin. Results We demonstrate that the spatial pattern of Culex abundance in catch basins is strongly influenced by environmental characteristics, resulting in significant variation across the urban landscape. Using regression and machine learning techniques, we described landscape features and microhabitat characteristics of four Chicago neighborhoods and examined the implications of these measures for larval abundance in adjacent catch basins. The important positive predictors of high larval abundance were aquatic ammonia, nitrates, and area of shrubs of height Culex during the fruit-bearing periods and early senescent periods in August and September. Conclusions This study identifies environmental predictors of mosquito production in urban environments. Because an abundance of adult Culex is integral to efficient WNV transmission and mosquitoes are found in especially high densities near larval habitats, identifying aquatic sites for Culex and landscape features that promote

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.

Mosquitoes of the genus Culex in the Suez Canal Governorates.

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Morsy, T A; el Okbi, L M; Kamal, A M; Ahmed, M M; Boshara, E F

1990-06-01

Mosquitoes are among the most annoying and important vectors of human and animal diseases as malaria, filariasis, yellow fever, rift valley fever...etc. In this paper, it was aimed to study the present status of species of genus Culex in the Suez Canal Governorates after the reconstruction and developmental projects. Five species of Culex were identified: C. pipiens, C. univittatus, C. antennatus, C. poicilipes and C. pusillus. The latter species was represented by two specimens. C. pipiens was the commonest species both indoors and outdoors. C. antennatus and C. poicilipes were found only outdoors. C. pipiens was found all the year round particularly in Spring. Other species were found in Spring and Autumn, except C. antennatus which was found in Summer as well. The results were discussed on the light of work done before.

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

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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

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

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

2017-07-01

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.

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

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Edward Pfeiler

2013-01-01

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

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

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

2013-01-01

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

Zika virus replication in the mosquito Culex quinquefasciatus in Brazil.

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Guedes, Duschinka Rd; Paiva, Marcelo Hs; Donato, Mariana Ma; Barbosa, Priscilla P; Krokovsky, Larissa; Rocha, Sura W Dos S; Saraiva, Karina LA; Crespo, Mônica M; Rezende, Tatiana Mt; Wallau, Gabriel L; Barbosa, Rosângela Mr; Oliveira, Cláudia Mf; Melo-Santos, Maria Av; Pena, Lindomar; Cordeiro, Marli T; Franca, Rafael F de O; Oliveira, André Ls de; Peixoto, Christina A; Leal, Walter S; Ayres, Constância Fj

2017-08-09

Zika virus (ZIKV) is a flavivirus that has recently been associated with an increased incidence of neonatal microcephaly and other neurological disorders. The virus is primarily transmitted by mosquito bite, although other routes of infection have been implicated in some cases. The Aedes aegypti mosquito is considered to be the main vector to humans worldwide; however, there is evidence that other mosquito species, including Culex quinquefasciatus, transmit the virus. To test the potential of Cx. quinquefasciatus to transmit ZIKV, we experimentally compared the vector competence of laboratory-reared Ae. aegypti and Cx. quinquefasciatus. Interestingly, we were able to detect the presence of ZIKV in the midgut, salivary glands and saliva of artificially fed Cx. quinquefasciatus. In addition, we collected ZIKV-infected Cx. quinquefasciatus from urban areas with high microcephaly incidence in Recife, Brazil. Corroborating our experimental data from artificially fed mosquitoes, ZIKV was isolated from field-caught Cx. quinquefasciatus, and its genome was partially sequenced. Collectively, these findings indicate that there may be a wider range of ZIKV vectors than anticipated.

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

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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

Assessment of Clarias gariepinus as a biological control agent against mosquito larvae.

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Chala, Buze; Erko, Berhanu; Animut, Abebe; Degarege, Abraham; Petros, Beyene

2016-05-31

The emergence and spread of insecticide resistant mosquitoes renewed interest in investigating the use of larvivorous fish as a biological control agent. The potential of Clarias gariepinus fish in controlling Anopheles arabiensis and culicine larvae was assessed under laboratory and semi-field conditions. Small size (15-20 cm) C. gariepinus fish consumed greater number of mosquito larvae than the large size fish (25-40 cm) in the multivariate regression model (β = 13.36, 95 % CI = 4.57, 22.15). The Anopheles larvae consumed was greater in number than the culicines larvae consumed by the fish (β = 12.10, 95 % CI = 3.31, 20.89). The number of larvae consumed was greater during the night hours than during the light hours (β = 30.06, 95 % CI = 21.27, 38.85). Amount of supplementary fish food did not cause significant differences in the number of mosquito larvae consumed by the fish among different groups. C. gariepinus was observed to feed on mosquito larvae under laboratory and semi-field conditions. C. gariepinus fed on the larvae of An. arabiensis and culicines readily. Hence, it can be used as an alternative mosquito control agent in Ethiopia where the breeding habitats are small and localized.

Wolbachia enhances West Nile virus (WNV infection in the mosquito Culex tarsalis.

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Brittany L Dodson

2014-07-01

Full Text Available Novel strategies are required to control mosquitoes and the pathogens they transmit. One attractive approach involves maternally inherited endosymbiotic Wolbachia bacteria. After artificial infection with Wolbachia, many mosquitoes become refractory to infection and transmission of diverse pathogens. We evaluated the effects of Wolbachia (wAlbB strain on infection, dissemination and transmission of West Nile virus (WNV in the naturally uninfected mosquito Culex tarsalis, which is an important WNV vector in North America. After inoculation into adult female mosquitoes, Wolbachia reached high titers and disseminated widely to numerous tissues including the head, thoracic flight muscles, fat body and ovarian follicles. Contrary to other systems, Wolbachia did not inhibit WNV in this mosquito. Rather, WNV infection rate was significantly higher in Wolbachia-infected mosquitoes compared to controls. Quantitative PCR of selected innate immune genes indicated that REL1 (the activator of the antiviral Toll immune pathway was down regulated in Wolbachia-infected relative to control mosquitoes. This is the first observation of Wolbachia-induced enhancement of a human pathogen in mosquitoes, suggesting that caution should be applied before releasing Wolbachia-infected insects as part of a vector-borne disease control program.

Larvicidal activity of neem oil (Azadirachta indica formulation against mosquitoes

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Dua Virendra K

2009-06-01

Full Text Available Abstract Background Mosquitoes transmit serious human diseases, causing millions of deaths every year. Use of synthetic insecticides to control vector mosquitoes has caused physiological resistance and adverse environmental effects in addition to high operational cost. Insecticides of botanical origin have been reported as useful for control of mosquitoes. Azadirachta indica (Meliaceae and its derived products have shown a variety of insecticidal properties. The present paper discusses the larvicidal activity of neem-based biopesticide for the control of mosquitoes. Methods Larvicidal efficacy of an emulsified concentrate of neem oil formulation (neem oil with polyoxyethylene ether, sorbitan dioleate and epichlorohydrin developed by BMR & Company, Pune, India, was evaluated against late 3rd and early 4th instar larvae of different genera of mosquitoes. The larvae were exposed to different concentrations (0.5–5.0 ppm of the formulation along with untreated control. Larvicidal activity of the formulation was also evaluated in field against Anopheles, Culex, and Aedes mosquitoes. The formulation was diluted with equal volumes of water and applied @ 140 mg a.i./m2 to different mosquito breeding sites with the help of pre calibrated knapsack sprayer. Larval density was determined at pre and post application of the formulation using a standard dipper. Results Median lethal concentration (LC50 of the formulation against Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti was found to be 1.6, 1.8 and 1.7 ppm respectively. LC50 values of the formulation stored at 26°C, 40°C and 45°C for 48 hours against Ae. aegypti were 1.7, 1.7, 1.8 ppm while LC90 values were 3.7, 3.7 and 3.8 ppm respectively. Further no significant difference in LC50 and LC90 values of the formulation was observed against Ae. aegypti during 18 months storage period at room temperature. An application of the formulation at the rate of 140 mg a.i./m2 in different breeding

DAYA LARVASIDA EKSTRAK BIJI SRIKAYA (ANNONA SQUAMOSA DENGAN RENTANG WAKTU PENYIMPANAN YANG BERBEDA TERHADAP LARVA CULEX QUINQUEFASCIATUS

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Wisnu Satria A.K.

2013-03-01

Full Text Available Abstract. Synthetic insecticide have been used to control Culex quinquefasciatus, but the prolonged usage of synthetic insecticide has a bad impact on the environment and may caused resistance. Sugar apple’s (Annona squamosa seeds which contain alkaloid can be used as an alternative insecticide that was safe for environment. This research aims is to know the effect of sugar apple’s seeds with different length of storage as C. quinquefasciatus larvacide. This research was an experimental study with a randomized controlled trial group design approach. The test material was an extract of sugar apple’s seeds which have been kept for 0, 1, 2, and 3 week with LC50 (0,47 ppm was used. Each treatment used 25 C. quinquefasciatus larvae from third instar larvae stage and replicated five times. After exposed for 24 hours, dead larvae counted. The result confirmed that the extract of sugar apple’s seeds which has been stored in 0, 1, 2, and 3 week did not showed any significant different on larvae mortality. Extract of sugar apple’s seeds which have been stored in 0, 1, 2, and 3 week have an equal activity as Culex quinquefasciatus larvicide. Key Word: Sugar apple (Annona squamosa, seeds, larvicide, Culex quinquefasciatus, length of storage Abstrak. Insektisida sintetik telah banyak digunakan untuk mengontrol Culex quinquefasciatus, tetapi penggunaan insektisida sintetik terus-menerus berdampak buruk terhadap lingkungan dan mengakibatkan resistensi. Fakta ini menjadi alasan biji srikaya (Annona squamosa yang mengandung alkaloid digunakan sebagai insektisida alternatif yang aman bagi lingkungan. Penelitian ini bertujuan untuk mengetahui pengaruh biji srikaya dengan perbedaan lama penyimpanan terhadap larva C. quinquefasciatus. Penelitian ini merupakan penelitian eksperimental dengan desain rancangan acak kelompok. Bahan uji adalah ekstrak biji srikaya yang telah disimpan selama 0, 1, 2, dan 3 minggu. Sampel penelitian ini adalah larva instar ketiga

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

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

2017-10-01

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

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).

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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

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

NARCIS (Netherlands)

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

2009-01-01

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

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

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Olger Calderón-Arguedas

2009-12-01

Full Text Available Field studies were conducted to determine the mosquito species richness in the urban area of Greater Puntarenas in Costa Rica. Two cross-sectional entomological surveys were performed in seven localities of Puntarenas: one survey was performed during the wet season and the other during the dry season. The sections evaluated were determined by applying a stratified cluster sampling method using satellite imagery, and a sample of 26 cells (100x100m was selected for the study. The number of cells per locality was proportional to the area of each locality. The presence of mosquito larvae and pupae in water-filled artificial and natural containers was determined in each cell. Infestation was expressed as a diversity index per type of container (Ii. Eight types of larvae were identified (Aedes aegypti, Culex quinquefasciatus, Culex interrogator, Culex nigripalpus, Culex corniger, Culex tarsalis, Limatus durhamii and Toxorhynchites theobaldi and in two cases it was only possible to identify the genus (Culex sp. and Uranotaenia sp.. A. aegypti was the most common species followed by C. quinquefascitus. Diversity of wet environments can explain the co-occurrence of various culicid species in some localities. Although A. aegypti is the only documented disease vector in the area, C quinquefasciatus, C. nigripalpus, and the other species of Culex could be considered potential vectors of other pathogens. The presence and ecology of all mosquito species should be studied to optimize surveillance and prevention of dengue and to prevent the emergence of other mosquito-transmitted diseases. Rev. Biol. Trop. 57 (4: 1223-1234. Epub 2009 December 01.La riqueza de especies de mosquitos urbanos de la Gran Puntarenas (Puntarenas, Costa Rica fue evaluada por medio de análisis larvales. Dos encuestas entomológicas fueron realizadas en siete localidades de la Gran Puntarenas durante un año. Una de las encuestas fue realizada en la estación seca y la otra se llevó a

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

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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.

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. This article is copyright of The Authors, 2016.

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

Institute of Scientific and Technical Information of China (English)

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

2004-01-01

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

Expresión de toxinas activas para larvas de mosquito por una cepa nativa de Asticaccaulis excentricus

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Sergio Ordúz

2000-02-01

Full Text Available

El control de mosquitos con insecticidas biológicos, como las toxinas producidas por especies del género Bacillus ha sido usado ampliamente en muchos países. Sin embargo, la rápida sedimentación de éstas las coloca fuera del alcance de la zona de alimentación de las larvas de mosquito. Con el propósito de resolver este problema se ha propuesto clonar los genes de dichas toxinas en bacterias acuáticas que son capaces de vivir y multiplicarse en la parte superior de la columna de agua, donde se alimentas los mosquitos anofelinos. Se escogieron dos cepas de la bacteria acuática Asticaccaulis excentricus para expresar los genes de la toxina binaria de B. sphaericus y el gen cry11Bb de B. thuringiensis subesp. Medellín clonados en un vector de expresión adecuado. En experimentos de alimentación se encontró que larvas de las especies Culex quinquefasciatus, Aedes aegypti y Anopheles albimanus fueron capaces de sobrevivir en una dieta basada exclusivamente en esta bacteria gram negativa. Las células de A. excentricus recombinante fueron capaces de expresar ambos genes, pero solamente la cepa expresando los genes de la toxina binaria de B. sphaericus fue tóxica para larvas de mosquito. Extractos de proteasas de A. excentricus no degradaron la toxina Cry11Bb, lo que indica que es otro el mecanismo que interfiere con la expresión de la toxicidad de la toxina Cry11Bb en esta bacteria recombinante. Los experimentos de flotación mostraron que A. excentricus recombiante se mantiene en la parte superior de la columna de agua al igual que las cepas nativas, y por más tiempo que las cepas de Bacillus.

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

Biocontrol of larval mosquitoes by Acilius sulcatus (Coleoptera: Dytiscidae

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Banerjee Siddhartha S

2008-10-01

Full Text Available Abstract Background Problems associated with resistant mosquitoes and the effects on non-target species by chemicals, evoke a reason to find alternative methods to control mosquitoes, like the use of natural predators. In this regard, aquatic coleopterans have been explored less compared to other insect predators. In the present study, an evaluation of the role of the larvae of Acilius sulcatus Linnaeus 1758 (Coleoptera: Dytiscidae as predator of mosquito immatures was made in the laboratory. Its efficacy under field condition was also determined to emphasize its potential as bio-control agent of mosquitoes. Methods In the laboratory, the predation potential of the larvae of A. sulcatus was assessed using the larvae of Culex quinquefasciatus Say 1823 (Diptera: Culicidae as prey at varying predator and prey densities and available space. Under field conditions, the effectiveness of the larvae of A. sulcatus was evaluated through augmentative release in ten cemented tanks hosting immatures of different mosquito species at varying density. The dip density changes in the mosquito immatures were used as indicator for the effectiveness of A. sulcatus larvae. Results A single larva of A. sulcatus consumed on an average 34 IV instar larvae of Cx. quinquefasciatus in a 24 h period. It was observed that feeding rate of A. sulcatus did not differ between the light-on (6 a.m. – 6 p.m., and dark (6 p.m. – 6 a.m. phases, but decreased with the volume of water i.e., space availability. The prey consumption of the larvae of A. sulcatus differed significantly (P A. sulcatus larvae, while with the withdrawal, a significant increase (p A. sulcatus in regulating mosquito immatures. In the control tanks, mean larval density did not differ (p > 0.05 throughout the study period. Conclusion the larvae of the dytiscid beetle A. sulcatus proved to be an efficient predator of mosquito immatures and may be useful in biocontrol of medically important mosquitoes.

Determination of Mosquitoes Fauna (Culicidae: Diptera in Poldokhtar County of Lorestan Province, 2015

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Zahirnia A H

2017-09-01

Full Text Available Introduction: Insects as the largest category of arthropods include numerous groups and families that the most important of them belong to order Diptera, family Culicidae. Because of feeding on the human's blood, a number of species of this family have been known as responsible for the transmission of pathogens for many diseases such as malaria, filariasis, encephalitis, yellow fever and dengue fever in the world. Given that no research has been conducted to determine the fauna of existing mosquitoes in the city of Poldokhtar, Lorestan Province, the present study aimed to exactly determine the mosquitoes' fauna in this city to perform appropriate prevention measures. Methods: In this faunistic and cross-sectional descriptive study, four urban areas and four rural areas in four geographic directions in the city of Poldokhtar were determined. In each urban area, two places and in each designated rural area, four places including two human places and two animal places were selected. From the early of April 2015 to the early of January 2016, larvae, pupae and adult mosquitoes of the Culicidae family were collected. Sampling methods for larvae, pupae and mature were ladling, night catch, total and hand catch with an aspirator. Characteristics including the name of the collector, date of collection, code related to habitat, habitat status (permanent or temporary, type of vegetation cover, type of substrate, and the situation of sunlight were recorded in the related form. The samples were identified by resources and valid identification keys. The data were analyzed using the SPSS software version 19. Results: Totally, 5392 mosquito adults of the Culicidae family including 1818 mosquito adults and 3574 larvae in designated areas in the city as well as four rural areas were collected. The three genera Anopheles (21.9%, Culex (64.6%, and Culiseta (13.5% were diagnosed. Also, from three genera, 12 species were identified as follows: Culex theiler, Cx

Distribution of Brugia malayi larvae and DNA in vector and non-vector mosquitoes: implications for molecular diagnostics

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Christensen Bruce M

2009-11-01

Full Text Available Abstract Background The purpose of this study was to extend prior studies of molecular detection of Brugia malayi DNA in vector (Aedes aegypti- Liverpool and non-vector (Culex pipiens mosquitoes at different times after ingestion of infected blood. Results Parasite DNA was detected over a two week time course in 96% of pooled thoraces of vector mosquitoes. In contrast, parasite DNA was detected in only 24% of thorax pools from non-vectors; parasite DNA was detected in 56% of midgut pools and 47% of abdomen pools from non-vectors. Parasite DNA was detected in vectors in the head immediately after the blood meal and after 14 days. Parasite DNA was also detected in feces and excreta of the vector and non-vector mosquitoes which could potentially confound results obtained with field samples. However, co-housing experiments failed to demonstrate transfer of parasite DNA from infected to non-infected mosquitoes. Parasites were also visualized in mosquito tissues by immunohistololgy using an antibody to the recombinant filarial antigen Bm14. Parasite larvae were detected consistently after mf ingestion in Ae. aegypti- Liverpool. Infectious L3s were seen in the head, thorax and abdomen of vector mosquitoes 14 days after Mf ingestion. In contrast, parasites were only detected by histology shortly after the blood meal in Cx. pipiens, and these were not labeled by the antibody. Conclusion This study provides new information on the distribution of filarial parasites and parasite DNA in vector and non-vector mosquitoes. This information should be useful for those involved in designing and interpreting molecular xenomonitoring studies.

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

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

2015-06-01

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

Evaluation of organophosphorus and synthetic pyrethroid insecticides against six vector mosquitoe species Avaliação de inseticidas organofosforados e piretroides sintéticos contra seis mosquitos vetores

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Domingo Montada Dorta

1993-12-01

Full Text Available Three organophosphorus compounds- malathion, folithion and temephos- and two synthetic pyrethroids- alphamethrin and deltamethrin- were used for monitoring the susceptibility status of larvae and adults of six vector mosquitoe species: Culex quinquefasciatus (Filariasis and Aedes albopictus (Dengue (both laboratory and field strains; laboratory strains of Aedes aegypti (Dengue, Anopheles slephensi and Anopheles culicifacies (Malaria, and Culex tritaeniorhynchus (Japanese encephalitis in India. From the LC50 values obtained for these insecticides, it was found that all mosquito species including the field strains of Cx. quinquefasciatus and Ae. albopictus were highly susceptible Except for Cx. quinquefasciatus (field strain against malathion, 100% mortality was observed at the discriminating dosages recommended by World Health Organization. The residual effect of alphamethrin, deltamethrin, malathion and folithion at 25 mg (ai/m² on different surfaces against six species of vector mosquitoes showed that alphamethrin was the most effective on all four treated surfaces (mud, plywood, cement and thatch. Nevertheless, residual efficacy lasted longer on thatch than on the other surfaces. Therefore, synthetic pyrethroids such as alphamethrin can be effectively employed in integrated vector control operations.Três compostos organo-fosforados - malation, folition e temefos -e dois piretroides sintéticos - alfametrina e deltametrina - foram usados para controlar o estado da susceptibilidade das larvas e adultos de seis mosquitos vetores na Índia. Foram utilizadas cepas de laboratório e área de Culex quinquefasciatus (filariasis e Aedes albopictus (Dengue e cepas de laboratório de Aedes aegypti (Dengue, Anopheles stephensi e Anopheles culicifacies (Malária e Culex tritaenorhynchus (encefalite japonesa. Os valores de C1(50 obtidos para esses inseticidas mostram que todas as espécies incluindo as cepas de área foram muito susceptíveis. Nos

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

A reverse transcriptase-PCR assay for detecting filarial infective larvae in mosquitoes.

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Sandra J Laney

2008-06-01

Full Text Available Existing molecular assays for filarial parasite DNA in mosquitoes cannot distinguish between infected mosquitoes that contain any stage of the parasite and infective mosquitoes that harbor third stage larvae (L3 capable of establishing new infections in humans. We now report development of a molecular L3-detection assay for Brugia malayi in vectors based on RT-PCR detection of an L3-activated gene transcript.Candidate genes identified by bioinformatics analysis of EST datasets across the B. malayi life cycle were initially screened by PCR using cDNA libraries as templates. Stage-specificity was confirmed using RNA isolated from infected mosquitoes. Mosquitoes were collected daily for 14 days after feeding on microfilaremic cat blood. RT-PCR was performed with primer sets that were specific for individual candidate genes. Many promising candidates with strong expression in the L3 stage were excluded because of low-level transcription in less mature larvae. One transcript (TC8100, which encodes a particular form of collagen was only detected in mosquitoes that contained L3 larvae. This assay detects a single L3 in a pool of 25 mosquitoes.This L3-activated gene transcript, combined with a control transcript (tph-1, accession # U80971 that is constitutively expressed by all vector-stage filarial larvae, can be used to detect filarial infectivity in pools of mosquito vectors. This general approach (detection of stage-specific gene transcripts from eukaryotic pathogens may also be useful for detecting infective stages of other vector-borne parasites.

Mosquitoes and other aquatic insects in fallow field biotopes and rice paddy fields.

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Ohba, S Y; Matsuo, T; Takagi, M

2013-03-01

Fallow field biotopes that develop from abandoned rice fields are man-made wetlands that provide new habitats for various aquatic animals. Although consideration of such biotopes generally focuses on their positive aspects, this study evaluated the negative aspects of establishing fallow field biotopes with regard to mosquito breeding sites. To determine whether fallow field biotopes become breeding habitats for vector mosquitoes, we evaluated mosquito fauna in fallow field biotopes and adjacent rice fields. We found larvae of Anopheles lesteri, Anopheles sinensis and Culex tritaeniorhynchus (all: Diptera: Culicidae) in the biotopes. Although abundances of mosquito larvae in the biotopes and rice fields were statistically similar, mosquito abundances in rice fields increased dramatically in August when the water level reduced after the rainy season. The abundance and variety of the mosquitoes' natural predators were greater in biotopes than in rice fields because the former are a permanent and stable aquatic environment. A generalized linear mixed model showed a negative effect of predator diversity on mosquito larvae abundance in both habitats. Although fallow field biotopes become breeding habitats for vector mosquitoes, establishing biotopes from fallow fields in order to protect various aquatic animals, including mosquito insect predators, may help to control mosquito breeding. © 2012 The Royal Entomological Society.

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.

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

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

2015-11-01

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

Larvicidal activity of lignans and alkaloid identified in Zanthoxylum piperitum bark toward insecticide-susceptible and wild Culex pipiens pallens and Aedes aegypti.

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Kim, Soon-Il; Ahn, Young-Joon

2017-05-04

The yellow fever mosquito, Aedes aegypti, and the common house mosquito, Culex pipiens pallens, transmit dengue fever and West Nile virus diseases, respectively. This study was conducted to determine the toxicity of the three lignans (-)-asarinin, sesamin and (+)-xanthoxylol-γ,γ-dimethylallylether (XDA), and the alkaloid pellitorine from Zanthoxylum piperitum (Rutaceae) bark to third-instar larvae from insecticide-susceptible C. pipiens pallens and Ae. aegypti as well as wild C. pipiens pallens resistant to deltamethrin, cyfluthrin, fenthion, and temephos. The toxicities of all isolates were compared with those of mosquito larvicide temephos. LC 50 values for each species and their treatments were significantly different from one another when their 95% confidence intervals did not overlap. XDA was isolated from Z. piperitum as a new larvicidal principle. XDA (LC 50 , 0.27 and 0.24 mg/l) was 4, 53, and 144 times and 4, 100, and 117 times more toxic than pellitorine, sesamin, and asarinin toward larvae from susceptible C. pipiens pallens and Ae. aegypti, respectively. Overall, all the isolates were less toxic than temephos (LC 50 , 0.006 and 0.009 mg/l). These constituents did not differ in toxicity to larvae from the two Culex strains. The present finding indicates that the lignans and alkaloid and the insecticides do not share a common mode of larvicidal action or elicit cross-resistance. Naturally occurring Z. piperitum bark-derived compounds, particularly XDA, merit further study as potential mosquito larval control agents or as lead compounds for the control of insecticide-resistant mosquito populations.

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.

Acute and chronic activity of perchlorate and hexavalent chromium contamination on the survival and development of Culex quinquefasciatus Say (Diptera: Culicidae)

International Nuclear Information System (INIS)

Sorensen, Mary A.; Jensen, Peter D.; Walton, William E.; Trumble, John T.

2006-01-01

Effects of water contamination with perchlorate and hexavalent chromium [Cr (VI)] on the mosquito Culex quinquefasciatus were assessed. The chronic (10-day) LC 5 s values for perchlorate and chromium were 74 ± 8.0 mg/L and 0.41 ± 0.15 mg/L, respectively. Relative Growth Index, a measure of growth and mortality rates in a population, was significantly reduced within 5 days for levels of perchlorate as low as 25 mg/L and for levels of chromium as low as 0.16 mg/L. Neither compound altered wing length of surviving adults. In combination, contaminants were synergistic, causing 14% more mortality than predicted. Acute (24-h) LC 5 values for perchlorate and Cr (VI) were 17,000 ± 3200 and 38 ± 1.3 mg/L, respectively. Effects on mosquito larvae in contaminated environments are likely to be observed for Cr (VI) but not for perchlorate, which generally does not occur at levels as high as those shown here to affect larval mosquitoes. - While pollution with hexavalent chromium may adversely affect Culex quinquefasciatus larvae, levels of perchlorate currently in the environment will not impact these insects

Acute and chronic activity of perchlorate and hexavalent chromium contamination on the survival and development of Culex quinquefasciatus Say (Diptera: Culicidae)

Energy Technology Data Exchange (ETDEWEB)

Sorensen, Mary A. [Department of Entomology, University of California, Riverside, CA 92521 (United States)]. E-mail: mary.sorensen@email.ucr.edu; Jensen, Peter D. [Department of Entomology, University of California, Riverside, CA 92521 (United States); Walton, William E. [Department of Entomology, University of California, Riverside, CA 92521 (United States); Trumble, John T. [Department of Entomology, University of California, Riverside, CA 92521 (United States)

2006-12-15

Effects of water contamination with perchlorate and hexavalent chromium [Cr (VI)] on the mosquito Culex quinquefasciatus were assessed. The chronic (10-day) LC{sub 5}s values for perchlorate and chromium were 74 {+-} 8.0 mg/L and 0.41 {+-} 0.15 mg/L, respectively. Relative Growth Index, a measure of growth and mortality rates in a population, was significantly reduced within 5 days for levels of perchlorate as low as 25 mg/L and for levels of chromium as low as 0.16 mg/L. Neither compound altered wing length of surviving adults. In combination, contaminants were synergistic, causing 14% more mortality than predicted. Acute (24-h) LC{sub 5} values for perchlorate and Cr (VI) were 17,000 {+-} 3200 and 38 {+-} 1.3 mg/L, respectively. Effects on mosquito larvae in contaminated environments are likely to be observed for Cr (VI) but not for perchlorate, which generally does not occur at levels as high as those shown here to affect larval mosquitoes. - While pollution with hexavalent chromium may adversely affect Culex quinquefasciatus larvae, levels of perchlorate currently in the environment will not impact these insects.

Evaluation of mosquito larvicidal activity of fruit extracts of Acacia auriculiformis against the Japanese encephalitis vector Culex vishnui.

Science.gov (United States)

Barik, Mousumi; Rawani, Anjali; Laskar, Subrata; Chandra, Goutam

2018-02-19

The larvicidal potentiality of crude and ethyl acetate extracts of fruits of Acacia auriculiformis was investigated against all the larval instars of JE vector Culex vishnui. The crude extracts showed good results against all the larval instars with highest mortality at 0.09%. Highest mortality was found at 300 ppm of ethyl acetate extract. Lowest LC 50 value was obtained at 72 h for third instar larvae. Non target organisms tested, showed no to very less mortality to ethyl acetate solvent extract. Presence of N-H stretching, a C=O stretching, C=C and C-N stretching vibrations of secondary amide or amine group were confirmed from IR analysis. GC-MS analysis revealed the presence of three compounds namely Ethane 2-chloro-1,1-dimethoxy, Acetic acid, 1-methyl ether ester and [4-[1-[3,5-Dimethyl-4[(trimethylsilyl)oxy)phenyl]-1,3-dimethylbutyl)-2,6dimethylphenoxy)(trimethyl) silane, responsible for mosquito larval death.

Long-term pathogenic response to Plasmodium relictum infection in Culex pipiens mosquito.

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Pigeault, Romain; Villa, Manon

2018-01-01

The transmission of Plasmodium within a vertebrate host population is strongly associated with the life history traits of its vector. Therefore the effect of malaria infection on mosquito fecundity and longevity has traditionally received a lot of attention. Several species of malaria parasites reduce mosquito fecundity, nevertheless almost all of the studies have focused only on the first gonotrophic cycle. Yet, during their lifetime, female mosquitoes go through several gonotrophic cycles, which raises the question of whether they are able to compensate the fecundity costs induced by the parasite. The impact of Plasmodium infection on female longevity is not so clear and has produced conflicting results. Here we measured the impact of Plasmodium relictum on its vector's longevity and fecundity during three consecutive gonotrophic cycles. In accordance with previous studies, we observed a negative impact of Plasmodium infection on mosquito (Culex pipiens) fecundity in the first gonotrophic cycle. Interestingly, despite having taken two subsequent uninfected blood meals, the negative impact of malaria parasite persisted. Nevertheless no impact of infection on mosquito longevity was observed. Our results are not in line with the hypothesis that the reduction of fecundity observed in infected mosquitoes is an adaptive strategy of Plasmodium to increase the longevity of its vector. We discuss the different underlying mechanisms that may explain our results.

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

DEFF Research Database (Denmark)

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

2016-01-01

. Methods: A total of 1800 laboratory reared mosquito larvae of each species were used in the bioassays. Twelve replicates were performed, each testing 6 concentrations of ivermectin (0.0, 0.001, 0.01, 0.1, 1.0 and 10.0 parts per million (ppm)) against third instar larvae of An. gambiae and Cx...

Toxic Response of Mosquito Culex Quinquefasciatus (Diptera: Culicidae to some Agricultural Pesticides (Butachlor and Pertilachlor

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Aliakbar Hedayati*

2017-06-01

Full Text Available Background: The expansion of herbicide used in aquatic ecosystems as well as in terrestrial if is not properly controlled may produce harmful effects on freshwater fisheries. Residue limits of these agricultural chemicals in tropical fishery waters should be established. The aim of this study was to determine the acute toxicity of butachlor and pertilachlor as potential dangerous herbicides to assess mortality effects of these chemicals to the Mosquito Culex quinquefasciatus. Methods: This study was carried out in Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran at summer 2013. Culex samples were exposed to different concentrations of butachlor and pertilachlor (0-200ppm for butachlor and pertilachlor for 96 h. Results: The low toxicity of LC50s obtained for butachlor (23.81±0.04 and pertilachlor (27.97±0.05 indicate that butachlor and pertilachlor were lowly toxic to Mosquito Cu. quinquefasciatus. Conclusion: Although pretilachlor and butachlor are low toxic but pretilachlor is less toxic in field conditions, these data are useful to potential ecosystem risk assessment.

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

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Dewi Nur Hodijah

2014-08-01

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

O aproveitamento do resíduo da indústria do sisal no controle de larvas de mosquitos

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Pizarro Ana Paula B.

1999-01-01

Full Text Available Descreve-se o aproveitamento do resíduo do desfibramento das folhas de Agave sisalana, como um larvicida para o combate a mosquitos transmissores de doenças tropicais. Durante 24 horas, larvas de Aedes aegypti e Culex quinquefasciatus foram expostas a concentrações diferentes do extrato da planta para determinar as concentrações letais. Para A. aegypti foi constatada a CL50 em 322ppm e para C. quinquefasciatus em 183ppm. Foi investigada a ação de saponinas existentes na planta, ficando evidenciado que o resíduo de A. sisalana é ativo através da interação de vários dos seus componentes. Este extrato poderá ser utilizado em campo, na concentração de 100ppm para C. quinquefasciatus com um aumento do tempo de exposição para três dias, obtendo-se uma mortalidade de 100% das larvas. Este produto, porém, não é recomendado para o controle de A. aegypti, devido à necessidade de uma alta concentração para a obtenção de 100% de mortalidade das larvas e ao fato destas se desenvolverem preferencialmente em água potável.

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.

Ultrastructural changes in the flight muscle mitochondria of adult male mosquito Culex Pipiens L I

International Nuclear Information System (INIS)

Abd Elmeguid, A.; Elmoursy, A.A.; Rouchdy, H.; Elzahraa, F.

1995-01-01

Ultrastructural differences between differentiating myoblasts of 1-day old pupae and 2-day old pupae and between well developed flight muscles in newly emerged 1-day old and 2-day old and ageing 21-day old adult male Culex Pipiens were studied. Ageing mosquitoes showed various signs of deterioration, vocalization, fusion and disorientation of cristae. 6 figs

[The mosquito fauna (Diptera: Culicidae) of the environs of the Sayan-Shushenskoe hydroelectric power station].

Science.gov (United States)

Gornostaeva, R M

1999-01-01

Among females and larvae of mosquitoes collected in 1969, 1981-1984 in the area of the Sayan-Shushenskoe hydroelectric power station (140 km up the Yenisei River from the Abakan city) 5 genera and 30 species were recorded. Based on recent collections and reference data (Gornostaeva e. a., 1969; Gornostaeva, Danilov, 1986) the fauna of the region in question includes 31 species of mosquitoes (Anopheles--1, Culiseta--2, Coquillettidia--1, Aedes--22, Culex--5).

Fauna, Ecological Characteristics, and Checklist of the Mosquitoes in Mazandaran Province, Northern Iran.

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Nikookar, Seyed Hassan; Fazeli-Dinan, Mahmoud; Azari-Hamidian, Shahyad; Nasab, Seyed Nouraddin Mousavi; Aarabi, Mohsen; Ziapour, Seyyed Payman; Enayati, Ahmadali; Hemingway, Janet

2018-05-04

Mosquitoes are important vectors of human and animal diseases. This study updates current knowledge on fauna, dominance, and distribution of mosquitoes in Mazandaran Province, Northern Iran, to inform disease control effort. Larval collections, using standard dippers or droppers, and adult collections, using total catches, shelter pits, CDC light traps, and human landing catches, were performed monthly in 30 villages across 16 counties, from May to December 2014. Ovitraps, baited with hay infusion as oviposition attractants or stimulants for Aedes (Stegomyia) mosquitoes, were installed in each village and inspected weekly for eggs. Lactophenol and Berlese media were used for preserving and mounting specimens. Overall, 36,024 mosquito specimens (19,840 larvae and 16,184 adults) belonging to 4 genera and 20 species were morphologically identified. The dominance and distribution indices showed that Culex pipiens s.s. was the eudominant species with a constant distribution of larvae (D = 69.07%, C = 100%) and adults (D = 31.86%, C = 100%), followed by Cx tritaeniorhynchus (D = 38.14%, C = 100%) and Anopheles maculipennis s.l. (D = 11.05%, C = 100%) as adults. Aedes vexans was the dominant (7.85%) species, but it had a sporadic (20%) distribution. Culex torrentium and Culiseta morsitans were added as the new species to the checklist of mosquitoes in Mazandaran Province. Due to the potential role, Cx. pipiens s.s. as a vector of various pathogens, further ecological studies are recommended.

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

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Maria Torres Olave

2015-12-01

Full Text Available The mosquitoes distribution and the presence of arboviruses are determined by temperature, rainfall, geographic barriers, and other factors that determine the distribution of Culex spp. and can influence the human arboviral. The objective of this study was to identify potential spatial distribution of Culex spp. The ecological niche modeling was performed using MaxEnt Ecological niche modeling was performed using MaxEnt, bioclimatic variables (WorldClim used for this process are derived from the monthly values of temperature and precipitation to generate biologically significant variables (representing annual trends and limiting factors for the distribution of species. The resulting maps can be interpreted as relative suitability areas, these areas are presented on the east coast of Mexico, mainly in the states of Veracruz and Tabasco. The results show that Bio 2 (mean monthly temperature range, Bio 7 (annual range of temperature and Bio 11 (mean temperature of the coldest quarter, determine the highest percentage range. Distribution modeling Culex spp. It is an approach to identify the most vulnerable areas in Mexico. It is necessary to strengthen and establish multidisciplinary programs for the prevention ofCulexspp transmitted diseases.

Exploring Mosquito Fauna of Majuro Atoll (Republic of Marshall Islands) in the Context of Zika Outbreak.

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Marie, Jérôme; Perera, Devika; Garstang, Helentina; Bossin, Herve C; Bourtzis, Kostas

2018-04-09

First autochthonous Zika clinical case was reported in the Republic of Marshall Islands (RMI) on Majuro Atoll in February 2016. An entomological survey of mosquito larvae and adult populations was carried out in four areas of Majuro, the most populated atoll of RMI encompassing different habitats (forest, rural, or urban) including some with confirmed clinical Zika cases to evaluate which mosquito species could be involved in the Zika transmission. A total of 2,367 immature and adult mosquito specimens were collected and identified to the species level. In total, five mosquito species were detected, Aedes aegypti (Linnaeus), Aedes albopictus (Skuse), Aedes marshallensis (Stone and Bohart), Culex quinquefasciatus (Say), and Culex annulirostris (Skuse) (Diptera: Culicidae), a first record for RMI. The most abundant species was Ae. aegypti presumed to be the main vector of Zika virus followed by Ae. albopictus. Improved management of breeding containers through better public awareness and community engagement, mosquito surveillance and innovative mosquito control strategies using the sterile insect technique (SIT) and/or the incompatible insect technique (IIT) could help prevent outbreaks of arboviruses in the RMI.

Riceland mosquito management practices for Anopheles quadrimaculatus larvae.

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Allen, R A; Wilkes, W W; Lewis, C N; Meisch, M V

2008-12-01

Two separate but related studies were conducted regarding management of Anopheles quadrimaculatus larval populations in commercial rice fields near Cleveland, MS, in 2004. Study 1 was to evaluate the effectiveness of 2 treatments of aerially applied ultra-low volume applications of Bacillus thuringiensis var. israelensis (Bti) against An. quadrimaculatus larvae in dense, high-canopy mid- to late-season rice crop. Study 2 was to investigate the effect of preflood treatments of lambda-cyhalothrin (Karate), which is commonly used against rice water weevil (Lissorhoptrus oryzophilus), on An. quadrimaculatus larvae. Excellent initial, but short residual control (>99% control 1 day after treatment) was observed in the Bti-treated fields in both mid- and late-season rice. Little or no effect on mosquito larvae was observed in the lambda-cyhalothrin-treated fields. Results indicate that Bti can be effectively used by mosquito management personnel to control larval populations of An. quadrimaculatus in late-season rice fields; however, lambda-cyhalothrin did not effectively control larval An. quadrimaculatus when applied preflood to rice fields.

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

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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

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

RNA splicing in a new rhabdovirus from Culex mosquitoes.

Science.gov (United States)

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

2011-07-01

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

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

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

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

2016-08-01

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

In vivo binding of the Cry11Bb toxin of Bacillus thuringiensis subsp. medellin to the midgut of mosquito larvae (Diptera: Culicidae

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Ruiz Lina María

2004-01-01

Full Text Available Bacillus thuringiensis subsp. medellin produces numerous proteins among which 94 kDa known as Cry11Bb, has mosquitocidal activity. The mode of action of the Cry11 proteins has been described as similar to those of the Cry1 toxins, nevertheless, the mechanism of action is still not clear. In this study we investigated the in vivo binding of the Cry11Bb toxin to the midgut of the insect species Anopheles albimanus, Aedes aegypti, and Culex quinquefasciatus by immunohistochemical analysis. Spodoptera frugiperda was included as negative control. The Cry11Bb protein was detected on the apical microvilli of the midgut epithelial cells, mostly on the posterior midgut and gastric caeca of the three mosquito species. Additionally, the toxin was detected in the Malpighian tubules of An. albimanus, Ae. aegypti, Cx. quinquefasciatus, and in the basal membrane of the epithelial cells of Ae. aegypti midgut. No toxin accumulation was observed in the peritrophic membrane of any of the mosquito species studied. These results confirm that the primary site of action of the Cry11 toxins is the apical membrane of the midgut epithelial cells of mosquito larvae.

Spinosad: a biorational mosquito larvicide for use in car tires in southern Mexico

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Marina Carlos F

2012-05-01

Full Text Available Abstract Background Car tires are important habitats for mosquito development because of the high density populations they can harbor and their presence in urban settings. Water in experimental tires was treated with one of three insecticides or an untreated control. Aquatic invertebrates were sampled at weekly intervals. Eggs, larval and pupal samples were laboratory-reared to estimate seasonal fluctuations in Aedes aegypti and Ae. albopictus abundance. Results Spinosad treatments at 1 or 5 ppm (mg a.i./liter provided 6–8 weeks of effective control of Ae. aegypti, Ae. albopictus, Culex quinquefasiatus and Cx. coronator larvae, both in the dry season and the rainy season when mosquito populations increased markedly in southern Mexico. Spinosad continued to provide partial control of larvae for several weeks after initial recolonization of treated tires. The larvicidal performance of VectoBac 12AS (Bacillus thuringiensis var. israelensis was relatively poor with one week of complete control of Aedes spp. larvae and no discernible control of Culex spp., whereas the duration of larvicidal activity of 1% temephos mineral-based granules was intermediate between those of VectoBac and spinosad treatments. Populations of chironomids, ostracods and Toxorhynchites theobaldi were generally reduced in spinosad and temephos treatments, but were similar in control and VectoBac treatments. Conclusion The present study is the first to report spinosad as an effective larvicide against Cx. coronator, which is currently invading the southern United States. These results substantiate the use of spinosad as a highly effective mosquito larvicide, even in habitats such as unused car tires that can represent prolific sources of adult mosquitoes.

Molecular detection of six (endo-) symbiotic bacteria in Belgian mosquitoes: first step towards the selection of appropriate paratransgenesis candidates.

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Raharimalala, Fara Nantenaina; Boukraa, S; Bawin, T; Boyer, S; Francis, F

2016-04-01

Actually, the use of symbiotic bacteria is one of alternative solution to avoid vector resistance to pesticides. In Belgium, among 31 identified mosquito species, 10 were considered as potential vectors. Given to introduction risks of arbovirosis, the purpose of this study was to investigate the presence of symbiosis bacteria in potential mosquito vectors. Eleven species caught from 12 sites in Belgium were used: Culex pipiens s.l., Culex torrentium, Culex hortensis, Anopheles claviger, Anopheles maculipennis s.l., Anopheles plumbeus, Culiseta annulata, Ochlerotatus geniculatus, Ochlerotatus dorsalis, Aedes albopictus, and Coquillettidia richiardii. Six genera of symbiotic bacteria were screened: Wolbachia sp., Comamonas sp, Delftia sp., Pseudomonas sp., Acinetobacter sp., and Asaia sp. A total of 173 mosquito individuals (144 larvae and 29 adults) were used for the polymerase chain reaction screening. Wolbachia was not found in any Anopheles species nor Cx. torrentium. A total absence of Comamonas and Delftia was observed in all species. Acinetobacter, Pseudomonas, and Asaia were found in most of species with a high prevalence for Pseudomonas. These results were discussed to develop potential strategy and exploit the variable occurrence of symbiotic bacteria to focus on them to propose biological ways of mosquito control.

First report of L1014F-kdr mutation in Culex pipiens complex from Morocco.

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Bkhache, Meriem; Tmimi, Fatim-Zohra; Charafeddine, Omar; Faraj, Chafika; Failloux, Anna-Bella; Sarih, M'hammed

2016-12-16

Mosquitoes of the Culex pipiens complex, competent vectors for West Nile virus (WNV) and Rift Valley fever virus (RVFV) are widely targeted by insecticide treatments. The intensive application of chemical insecticides led to the development of resistance in many insects including Culex pipiens mosquitoes. The absence of data on resistance mechanisms in Morocco allow us to assess the levels of lambda-cyhalothrin resistance and the frequency of the mutated gene L1014F kdr in different forms of Cx. pipiens complex from three regions of Morocco. Mosquito adults were reared from immature stages collected in three different regions in Morocco (Tangier, Casablanca and Marrakech). Standard WHO insecticide susceptibility tests were conducted on adults emerged from collected larvae. Specimens were identified as belonging to the Culex pipiens complex using a multiplex PCR assay with diagnostic primers designed from the flanking region of microsatellite CQ11. Identified mosquitoes were then tested for the presence of the L1014F kdr mutation using PCR assay. Our results showed that 21% of the tested population has a resistance to lambda-cyhalothrin. The molecular identification of survivors shows that 43% belonged to the Cx. pipiens pipiens and only 9.5% to the Cx. pipiens molestus form. On the other hand, 416 specimens were screened for the L1014F kdr mutation. L1014F mutation was detected in different forms of Cx. pipiens in different sites. The frequency of L1014F mutation was similar between the Cx. pipiens pipiens form and hybrid form, while it was lower in the Cx. pipiens molestus form. The presence of the L1014F kdr allele was significantly associated with resistance to lambda-cyhalothrin in Cx. pipiens pipiens (P Morocco. These findings will provide important information to propose more adapted vector control measures towards this mosquito species, potential vector of arboviruses.

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

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

2009-01-01

Effective management of avian malaria (Plasmodium relictum) in Hawai'i's endemic honeycreepers (Drepanidinae) requires the identification and subsequent reduction or treatment of larval habitat for the mosquito vector, Culex quinquefasciatus (Diptera: Culicidae). We conducted ground surveys, treehole surveys, and helicopter aerial surveys from 20012003 to identify all potential larval mosquito habitat within two 100+ ha mesic-dry forest study sites in Hawai'i Volcanoes National Park, Hawai'i; 'Ainahou Ranch and Mauna Loa Strip Road. At 'Ainahou Ranch, anthropogenic sites (43%) were more likely to contain mosquitoes than naturally occurring (8%) sites. Larvae of Cx. quinquefasciatus were predominately found in anthropogenic sites while Aedes albopictus larvae occurred less frequently in both anthropogenic sites and naturally-occurring sites. Additionally, moderate-size (???20-22,000 liters) anthropogenic potential larval habitat had >50% probability of mosquito presence compared to larger- and smaller-volume habitat (malaria, may be controlled by larval habitat reduction in the mesic-dry landscapes of Hawai'i where anthropogenic sources predominate.

Metallic copper spray--a new control technique to combat invasive container-inhabiting mosquitoes.

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Becker, Norbert; Oo, Thin Thin; Schork, Nino

2015-11-09

The control of container-inhabiting mosquitoes is mainly based on environmental management with special emphasis on community participation e.g. source reduction by elimination or modification of water bodies. However, citizens are often not aware of the problems related to urban mosquito control or just ignore the advice provided during anti-mosquito control campaigns. In particular, cemeteries contain favourite breeding sites for container-inhabiting mosquitoes like Ochlerotatus j. japonicus, Culex pipiens s.l./Cx. torrentium, Aedes aegypti or Aedes albopictus. In our study, we investigated whether metallic copper e.g. in form of copper spray can be a suitable and cost-effective tool to combat mosquito breeding in vases or other similar small containers where no commonly used insecticides can be applied. The effect of metallic copper spray in comparison to 5 Euro cent coins or copper tubes at different dosages and water qualities applied in small water collections such as widely used plastic grave vases were evaluated by assessing the mortality rates of larvae of Oc.j. japonicus, Cx. pipiens s.l./Cx. torrentium and Ae.aegypti. Different water qualities were tested to assess the influence of pH on the solubility of the copper ions. The copper concentrations were quantified using ICP/MS (Inductively coupled plasma/Mass spectrometry) in relation to the exposure time and mortality rates of mosquito larvae. All statistical analyses were computed using JMP 10.0.2 (SAS Institute Inc., 2012, Cary, NC, USA). Dosages of less than 500 ppb of copper in the water of small containers led to a 100% mortality rate after 2 weeks for all tested mosquito species by using one or more 5 Euro cent coins/vase. When the interior surface of plastic grave vases was covered by metallic copper spray, all of the tested larvae died after 7-10 days in the laboratory and under field conditions the reduction rate was 99.44% for Oc.j. japonicus and 99.6% for Culex pipiens s.l./Cx. torrentium

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

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K. Dass

2014-06-01

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

Presence of Aedes and Anopheles mosquito larvae is correlated to bacteria found in domestic water-storage containers.

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Nilsson, Louise K J; Sharma, Anil; Bhatnagar, Raj K; Bertilsson, Stefan; Terenius, Olle

2018-06-01

Water-storage containers are common in households where access to water is scarce and often act as breeding sites for vector mosquitoes. Bacteria in these containers may be important for attracting or repelling ovipositing mosquitoes. We hypothesized that bacterial community composition in water-storage containers would represent either inhibitory or suitable environmental conditions for mosquito larvae. To investigate this, we characterized the bacterial community composition in water-storage containers and correlated these communities to Aedes and Anopheles larval densities. Water samples were collected over two years from 13 containers in an Indian village and analyzed by high throughput 16S rRNA gene amplicon sequencing. Comparisons of bacterial community composition between water with and without mosquito larvae showed that Xanthomonadaceae, Comamonadaceae and Burkholderiaceae were more common (P < 0.05) in absence of larvae, while Lachnospiraceae, Synechococcaceae, Alcaligenaceae and Cryomorphaceae were more common (P < 0.05) in presence of larvae. Indicator analysis identified operational taxonomic units designated as CL500-29 marine group (Acidimicrobiaceae) and FukuN101 (Microbacteriaceae) for absence and presence of larvae, respectively. These results contribute to the understanding of which bacteria, directly or indirectly, can be linked to absence or presence of mosquitoes around households and set the basis for potential measures to be taken against these vector mosquitoes.

Polymeric nanoencapsulation of insect repellent: Evaluation of its bioefficacy on Culex quinquefasciatus mosquito population and effective impregnation onto cotton fabrics for insect repellent clothing

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A.P.B. Balaji

2017-10-01

Full Text Available Diethylphenylacetamide (Bulk-DEPA, an organic insect repellent was subjected to Poly(ethylene glycol (PEG polymerization followed by Phase Inversion Temperature (PIT emulsification method to yield the polymeric nanodroplets of DEPA (Nano-DEPA. The mean hydrodynamic diameter was found to be 149 ± 1.06 nm. The efficacy of Bulk-DEPA and Nano-DEPA was comparatively investigated on the Culex quinquefasciatus mosquito population. The larvicidal bioassay was performed on the 1st, 2nd, and 3rd instar larvae of Culex quinquefasciatus and the median lethal indices (LC50 of was found to be 0.055, 0.208, 1.397 mg/L and 0.023, 0.144, 0.260 mg/L for Bulk-DEPA and Nano-DEPA respectively. The histopathological studies were found to be corroborative with the larvicidal bioassay. The median knockdown indices (KD50 on 2–3 day old sucrose fed adult mosquitoes determined by WHO cone bioassay and was found to be 55.168 and 33.277 mg/L for Bulk-DEPA and Nano-DEPA. The obtained results indicate the improved efficacy possessed by the Nano-DEPA as comparative to Bulk-DEPA even at lower concentrations. Further, the Nano-DEPA was impregnated onto the alginate cross-linked (ACL and Plain (PL cotton fabrics, and the Washing resistance index (WRI was determined. The obtained results indicate the higher WRI possessed by the ACL cotton fabric than the PL cotton fabric. This was owing to the effective physical entrapment of Nano-DEPA onto the alginate matrices, which was further substantiated by high-resolution scanning electron microscopic (HR-SEM studies. Overall, the present study has emphasized the benefit of formulating Bulk-DEPA into Nano-DEPA to exert higher efficacy on the mosquito population. In addition, study has provided the methodology for the effective impregnation of Nano-DEPA onto the cotton fabrics for the reliable application in long lasting insect repellent clothing.

Avian Plasmodium in Eastern Austrian mosquitoes.

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Schoener, Ellen; Uebleis, Sarah Susanne; Butter, Julia; Nawratil, Michaela; Cuk, Claudia; Flechl, Eva; Kothmayer, Michael; Obwaller, Adelheid G; Zechmeister, Thomas; Rubel, Franz; Lebl, Karin; Zittra, Carina; Fuehrer, Hans-Peter

2017-09-29

Insect vectors, namely mosquitoes (Diptera: Culicidae), are compulsory for malaria parasites (Plasmodium spp.) to complete their life cycle. Despite this, little is known about vector competence of different mosquito species for the transmission of avian malaria parasites. In this study, nested PCR was used to determine Plasmodium spp. occurrence in pools of whole individuals, as well as the diversity of mitochondrial cytochrome b gene sequences in wild-caught mosquitoes sampled across Eastern Austria in 2013-2015. A total of 45,749 mosquitoes in 2628 pools were collected, of which 169 pools (6.43%) comprising 9 mosquito species were positive for avian Plasmodium, with the majority of positives in mosquitoes of Culex pipiens s.l./Culex torrentium. Six different avian Plasmodium lineages were found, the most common were Plasmodium vaughani SYAT05, Plasmodium sp. Linn1 and Plasmodium relictum SGS1. In 2014, mosquitoes of the Culex pipiens complex were genetically identified and Culex pipiens f. pipiens presented with the highest number of avian Plasmodium positives (n = 37; 16.74%). Despite this, the minimum infection rate (MIR) was highest in Culex torrentium (5.36%) and Culex pipiens f. pipiens/f. molestus hybrids (5.26%). During 2014 and 2015, seasonal and annual changes in Plasmodium lineage distribution were also observed. In both years P. vaughani SYAT05 dominated at the beginning of the sampling period to be replaced later in the year by P. relictum SGS1 (2014) and Plasmodium sp. Linn1 (2015). This is the first large-scale study of avian Plasmodium parasites in Austrian mosquitoes. These results are of special interest, because molecular identification of the taxa of the Cx. pipiens complex and Cx. torrentium enabled the determination of Plasmodium prevalence in the different mosquito taxa and hybrids of this complex. Since pools of whole insects were used, it is not possible to assert any vector competence in any of the examined mosquitoes, but the results

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

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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.

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

Transmission of Rift Valley fever virus from European-breed lambs to Culex pipiens mosquitoes.

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Rianka P M Vloet

2017-12-01

Full Text Available Rift Valley fever virus (RVFV is a mosquito-borne bunyavirus of the genus Phlebovirus that is highly pathogenic to ruminants and humans. The disease is currently confined to Africa and the Arabian Peninsula, but globalization and climate change may facilitate introductions of the virus into currently unaffected areas via infected animals or mosquitoes. The consequences of such an introduction will depend on environmental factors, the availability of susceptible ruminants and the capacity of local mosquitoes to transmit the virus. We have previously demonstrated that lambs native to the Netherlands are highly susceptible to RVFV and we here report the vector competence of Culex (Cx. pipiens, the most abundant and widespread mosquito species in the country. Vector competence was first determined after artificial blood feeding of laboratory-reared mosquitoes using the attenuated Clone 13 strain. Subsequently, experiments with wild-type RVFV and mosquitoes hatched from field-collected eggs were performed. Finally, the transmission of RVFV from viremic lambs to mosquitoes was studied.Artificial feeding experiments using Clone 13 demonstrated that indigenous, laboratory-reared Cx. pipiens mosquitoes are susceptible to RVFV and that the virus can be transmitted via their saliva. Experiments with wild-type RVFV and mosquitoes hatched from field-collected eggs confirmed the vector competence of Cx. pipiens mosquitoes from the Netherlands. To subsequently investigate transmission of the virus under more natural conditions, mosquitoes were allowed to feed on RVFV-infected lambs during the viremic period. We found that RVFV is efficiently transmitted from lambs to mosquitoes, although transmission was restricted to peak viremia. Interestingly, in the mosquito-exposed skin samples, replication of RVFV was detected in previously unrecognized target cells.We here report the vector competence of Cx. pipiens mosquitoes from the Netherlands for RVFV. Both

Loss of protection with insecticide-treated nets against pyrethroid-resistant Culex quinquefasciatus mosquitoes once nets become holed: an experimental hut study

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Irish SR

2008-06-01

Full Text Available Abstract Background An important advantage of pyrethroid-treated nets over untreated nets is that once nets become worn or holed a pyrethroid treatment will normally restore protection. The capacity of pyrethroids to kill or irritate any mosquito that comes into contact with the net and prevent penetration of holes or feeding through the sides are the main reasons why treated nets continue to provide protection despite their condition deteriorating over time. Pyrethroid resistance is a growing problem among Anopheline and Culicine mosquitoes in many parts of Africa. When mosquitoes become resistant the capacity of treated nets to provide protection might be diminished, particularly when holed. An experimental hut trial against pyrethroid-resistant Culex quinquefasciatus was therefore undertaken in southern Benin using a series of intact and holed nets, both untreated and treated, to assess any loss of protection as nets deteriorate with use and time. Results There was loss of protection when untreated nets became holed; the proportion of mosquitoes blood feeding increased from 36.2% when nets were intact to between 59.7% and 68.5% when nets were holed to differing extents. The proportion of mosquitoes blood feeding when treated nets were intact was 29.4% which increased to 43.6–57.4% when nets were holed. The greater the number of holes the greater the loss of protection regardless of whether nets were untreated or treated. Mosquito mortality in huts with untreated nets was 12.9–13.6%; treatment induced mortality was less than 12%. The exiting rate of mosquitoes into the verandas was higher in huts with intact nets. Conclusion As nets deteriorate with use and become increasingly holed the capacity of pyrethroid treatments to restore protection is greatly diminished against resistant Culex quinquefasciatus mosquitoes.

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.

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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.

Environmental and social-demographic predictors of the southern house mosquito Culex quinquefasciatus in New Orleans, Louisiana.

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Moise, Imelda K; Riegel, Claudia; Muturi, Ephantus J

2018-04-17

Understanding the major predictors of disease vectors such as mosquitoes can guide the development of effective and timely strategies for mitigating vector-borne disease outbreaks. This study examined the influence of selected environmental, weather and sociodemographic factors on the spatial and temporal distribution of the southern house mosquito Culex quinquefasciatus Say in New Orleans, Louisiana, USA. Adult mosquitoes were collected over a 4-year period (2006, 2008, 2009 and 2010) using CDC gravid traps. Socio-demographic predictors were obtained from the United States Census Bureau, 2005-2009 American Community Survey and the City of New Orleans Department of Code Enforcement. Linear mixed effects models and ERDAS image processing software were used for statistical analysis and image processing. Only two of the 22 predictors examined were significant predictors of Cx. quinquefasciatus abundance. Mean temperature during the week of mosquito collection was positively associated with Cx. quinquefasciatus abundance while developed high intensity areas were negatively associated with Cx. quinquefasciatus abundance. The findings of this study illustrate the power and utility of integrating biophysical and sociodemographic data using GIS analysis to identify the biophysical and sociodemographic processes that increase the risk of vector mosquito abundance. This knowledge can inform development of accurate predictive models that ensure timely implementation of mosquito control interventions.

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.

Effects of heavy metals on population growth and metallothionein gene expression in the mosquito Culex quinquefasciatus, from Calcutta, India

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Sarkar, Sagartirtha; Duttagupta, Asish K.; Mal, Tarun K.

2004-01-01

Major water bodies in and around the city of Calcutta (India) receive heavy metal contaminated effluents from industries, households, and vehicular traffic through sewage or drainage. We quantified concentrations of Cu, Zn, and Cd from three water bodies at Kalighat, Tangra, and VIP Road, respectively. The concentrations of these heavy metals were significantly greater in the summer than in monsoon when heavy downpours resulted in reduced metal concentrations. Concentrations of metals in the mosquito Culex quinquefasciatus also reflected such seasonal fluctuations. Hatchability and survivorship of C. quinquefasciatus significantly differed among the sites and were reduced significantly from the control. Exposure to heavy metals also induced MT-gene expression in C. quinquefasciatus, likely helping them to survive in the water bodies stressed with heavy metals. MT-gene activity demonstrated significant variation among sites and seasons with the highest activity in the summer in the VIP Road population. This study suggests that C. quinquefasciatus could be used as an ecological indicator of heavy metal pollution by monitoring its MT-gene expression. - The mosquito, Culex quinquefasciatus, might be useful as an indicator of trace metals

Effects of heavy metals on population growth and metallothionein gene expression in the mosquito Culex quinquefasciatus, from Calcutta, India

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Sarkar, Sagartirtha; Duttagupta, Asish K.; Mal, Tarun K

2004-01-01

Major water bodies in and around the city of Calcutta (India) receive heavy metal contaminated effluents from industries, households, and vehicular traffic through sewage or drainage. We quantified concentrations of Cu, Zn, and Cd from three water bodies at Kalighat, Tangra, and VIP Road, respectively. The concentrations of these heavy metals were significantly greater in the summer than in monsoon when heavy downpours resulted in reduced metal concentrations. Concentrations of metals in the mosquito Culex quinquefasciatus also reflected such seasonal fluctuations. Hatchability and survivorship of C. quinquefasciatus significantly differed among the sites and were reduced significantly from the control. Exposure to heavy metals also induced MT-gene expression in C. quinquefasciatus, likely helping them to survive in the water bodies stressed with heavy metals. MT-gene activity demonstrated significant variation among sites and seasons with the highest activity in the summer in the VIP Road population. This study suggests that C. quinquefasciatus could be used as an ecological indicator of heavy metal pollution by monitoring its MT-gene expression. - The mosquito, Culex quinquefasciatus, might be useful as an indicator of trace metals.

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

Insecticidal activity of some citrus oils against culex quinquefasciatus

International Nuclear Information System (INIS)

Saeed, H. M. A.

2009-01-01

The present study deals with the larvicidal potency of peel oils of grapefruit (Citrus paradise), sweet orange (Citrus sinensis) and lime (Citrus aurantifolia) on 4''th instar larvae of the mosquito, Culex quinquefasciatus. Orange oil was the most effective followed by grapefruit oil and then lime oil. The toxicity of the oils applied to the 4''th instar larval stage was extended to pupal and adult stages. All oils produced deleterious effects on fecundity of survivors of sublethal doses. By the aid of chemical analysis of oils, the active compound was found to be limonene, a monoterpene compound. The percentages limonene were 97.15%, 92.46% and 32.29% for orange, grapefruit and lime respectively.(Author)

Factors influencing the predation rates of Anisops breddini (Hemiptera: Notonectidae feeding on mosquito larvae

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R. Weterings

2014-12-01

Full Text Available Notonectidae are a family of water bugs that are known to be important predators of mosquito larvae and have great potential in the biological control of vector mosquitoes. An experiment was conducted to assess mosquito larvae predation by Anisops breddini, a species common to Southeast Asia. The predation rates were recorded in context of prey density, predator density, predator size and prey type. Predation rates were strongly affected by prey type and less by prey density and predator density. They ranged between 1.2 prey items per day for pupae of Aedes aegeypti and Armigeres moultoni to 5.9 for Ae. aegypti larvae. Compared with studies on other Notonectidae species, the predation rates appear low, which is probably caused by the relative small size of the specimens used in this study. An. breddini is very common in the region and often found in urban areas; therefore, the species has potential as a biological control agent.

Screening of Bacillus thuringiensis strains effective against mosquitoes Prospecção de estirpes de Bacillus thuringiensis efetivas contra mosquitos

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Rose Gomes Monnerat

2005-02-01

Full Text Available The objective of this work was to evaluate 210 Bacillus thuringiensis strains against Aedes aegypti and Culex quinquefasciatus larvae to select the most effective. These strains were isolated from different regions of Brazil and are stored in a Bacillus spp. collection at Embrapa Recursos Genéticos e Biotecnologia, Brasília, Brazil. The selected strains were characterized by morphological (microscopy, biochemical (SDS-PAGE 10% and molecular (PCR methods. Six B. thuringiensis strains were identified as mosquito-toxic after the selective bioassays. None of the strains produced the expected PCR products for detection of cry4, cry11 and cyt1A genes. These results indicate that the activity of mosquitocidal Brazilian strains are not related with Cry4, Cry11 or Cyt proteins, so they could be used as an alternative bioinsecticide against mosquitoes.Neste trabalho foram realizados testes de patogenicidade com 210 estirpes de Bacillus thuringiensis contra larvas de Aedes aegypti e Culex quinquefasciatus, a fim de se determinar as mais eficazes. Estas estirpes foram isoladas de diversas regiões do Brasil e estão armazenadas na coleção de Bacillus spp. da Embrapa Recursos Genéticos e Biotecnologia. As estirpes selecionadas foram caracterizadas por métodos morfológicos (microscopia, bioquímicos (SDS-PAGE 10% e moleculares (Reação em Cadeia da Polimerase. Foram selecionadas seis estirpes entomopatogênicas de Bacillus thuringiensis. Nenhuma das estirpes de Bacillus thuringiensis apresentou produtos de PCR esperados para a detecção dos genes cry4, cry11 e cyt1A. A patogenicidade das estirpes não está associada à presença das toxinas Cry4, Cry11 ou Cyt, assim, essas estirpes poderão ser utilizadas para a formatação de um bioinseticida alternativo contra mosquitos.

Larvicidal effect of aqueous and ethanolic extracts of Senna alata on Anopheles gambiae, Culex quinquefasciatus and Aedes aegypti.

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Edwin, Ubulom Peace Mayen; Nyiutaha, Imandeh Godwin; Essien, Akpabio Eno; Nnamdi, Opara Kenneth; Sunday, Ekanem Mfon

2013-05-01

Senna alata is locally used in South Eastern Nigeria in the treatment of several infections which include ringworm and other parasitic skin diseases.The larvicidal activities of aqueous and ethanolic leaf and stem extracts of S. alata were evaluated in static bioassays, on fourth instar larvae of Anopheles gambiae, Culex quinquefasciatus and Aedes aegypti, at extract concentrations of 0.15, 0.30, 0.45, 0.60 and 0.75% w/v, for 72 hours. Mortality of larvae exposed to the different extracts increased with increase in extract concentration and time of exposure. This study revealed a differential potency of the extracts used and a difference in susceptibility of larvae to the extracts as evident by the 72hLC₅₀ values obtained. The leaf extract proved to be more lethal to the larvae than the stem extract as judged by the 72hLC₅₀ values obtained both for the aqueous as well as the ethanolic extracts assayed. Phytochemical screening of the plant parts investigated revealed the presence of some plant metabolites, which have been reported in separate studies to be lethal to mosquito larvae. Results obtained from this study suggest that the leaf and stem extracts of S. alata possess a promising larvicidal potential which can be exploited in mosquito vector control.

Pharmaceuticals and personal care products alter the holobiome and development of a medically important mosquito

International Nuclear Information System (INIS)

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

2015-01-01

The increasing demand for fresh water has forced many countries to use reclaimed wastewater for agricultural purposes. This water contains pharmaceuticals and personal care products (PPCPs) that remain biologically active following passage through wastewater treatment plants. Run-off from farms and contaminated water from treatment facilities exposes aquatic ecosystems to PPCPs. This study examined the effects of PPCPs on a lower trophic organism. Culex quinquefasciatus larvae were reared in water contaminated with environmentally relevant concentrations of common PPCPs. Acetaminophen alone and a mixture of contaminants were found to increase developmental time of larvae. Susceptibility to Bti increased in larvae exposed to antibiotics, acetaminophen, or a mixture of PPCPs. Antibiotics, hormones, and the mixture altered the mosquito bacterial microbiome. Overall, the results indicate that at environmentally relevant concentrations, PPCPs in reclaimed water can have biologically important effects on an ecologically and medically important lower trophic level insect. - Highlights: • Effects of Pharmaceuticals and Personal Care Products on mosquitoes were examined. • Three PPCP treatments increase susceptibility to a common larvicide (Bti). • Acetaminophen and the mixture of PPCPs caused an increase in developmental time. • The holobiome of mosquitoes treated with PPCPs were sequenced. • Three PPCP regimes changed the holobiome of the mosquitoes. - Pharmaceuticals and personal care products, common to reclaimed wastewater, alter the development of mosquitoes. They also alter the whole-body bacterial microbiome

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

Science.gov (United States)

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

2010-01-01

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

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.

Fate of labelled allitin in bean plant and mosquito

International Nuclear Information System (INIS)

Banerji, A.; Chintalwar, G.J.; Ramakrishnan, V.

1980-01-01

Allitin, the insecticidal principle of garlic (Allium sativum L) is a mixture of diallyl di- and tri-sulfides. 35 S-labelled allitin has been synthesised using different methods and used for the evaluation of its persistence in water. Results of these experiments showed that allitin has low persistence; more than 80% of the initial radioactivity was lost in 24 hr. when an aqueous emulsion of labelled allitin was exposed under the laboratory conditions. Fate of labelled allitin was studied in larvae and pupae of mosquitoes, Culex pipiens quinquefasciatus Say. Assimilation of allitin was found to be faster in larva compared to pupa. Intake of allitin by bean plant was also studied. Implications of the results obtained in the above experiments will be discussed. (author)

Evaluation of Mesocyclops aspericornis (Cyclopoida:Cyclopidae) and Toxorhynchites speciosus as integrated predators of mosquitoes in tire habitats in Queensland.

Science.gov (United States)

Brown, M D; Hendrikz, J K; Greenwood, J G; Kay, B H

1996-09-01

This study addressed biological control of peridomestic Aedes notoscriptus, known to be a highly effective colonizer of tire habitats and a possible vector of Ross River virus. A laboratory trial of the compatibility of the predators Mesocyclops aspericornis and Toxorhynchites speciosus in small container habitats showed that 4th-instar Tx. speciosus did not significantly affect M. aspericornis mortality. Introduced M. aspericornis and naturally occurring Tx. speciosus were found to form a compatible predator pair for reduction of larval Ae. notoscriptus and Culex quinquefasciatus populations in tire habitats. Over 22 months of field survey, 97% of tires without predators contained mosquito larvae, at a median density of 43 larvae/liter. By comparison, 51% of tires containing both predator species held mosquito larvae at a median density of 4 larvae/liter. Predation by Tx. speciosus persisted for the duration of the study. The inability of the Lake Kurwongbah strain of M. aspericornis to tolerate temperatures of winter, resulted in a failure to deliver persistent reduction of mosquitoes in tires. The temperature-dependent population characteristics of M. aspericornis emphasize the long-recognized importance of matching a biological control candidate's physiological requirements to the environment in which control is sought.

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

Biological control agent for mosquito larvae: Review on the killifish ...

African Journals Online (AJOL)

This review attempts to give an account on the recent advances on the killifish Aphanius dispar dispar as a biological control agent for mosquito larvae. Thirty six (36) articles of literature (scientific papers, technical and workshop reports) on this subject covering the period between 1980 and 2009 were reviewed.

Fauna and Larval Habitats of Mosquitoes (Diptera: Culicidae of West Azerbaijan Province, Northwestern Iran.

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Farahnaz Khoshdel-Nezamiha

2014-12-01

Full Text Available Several important diseases are transmitted by mosquitoes. Despite of the potential of the occurrence of some mosquito-borne diseases such as West Nile, dirofilariasis and malaria in the region, there is no recent study of mosquitoes in West Azerbaijan Province. The aim of this investigation was to study the fauna, composition and distribution of mosquitoes and the characteristics of their larval habitats in this province.Larvae and adult collections were carried out from different habitats using the standard methods in twenty five localities of seven counties across West Azerbaijan Province.Overall, 1569 mosquitoes including 1336 larvae and 233 adults were collected from 25 localities. The details of geographical properties were recorded. Five genera along with 12 species were collected and identified including: Anopheles claviger, An. maculipennis s.l., An. superpictus, Culex pipiens, Cx. theileri, Cx. modestus, Cx. hortensis, Cx. mimeticus, Culiseta Longiareolata, Ochlerotatus caspius s.l., Oc. geniculatus and Uranotaenia unguiculata. This is the first record of Oc. geniculatus in the province.Due to the geographical location of the West Azerbaijan Province, it comprises different climatic condition which provides suitable environment for the establishment of various species of mosquitoes. The solidarity geographical, cultural and territorial exchanges complicate the situation of the province and its vectors as a threat for future and probable epidemics of mosquito-borne diseases.

The costs of infection and resistance as determinants of West Nile virus susceptibility in Culex mosquitoes

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Styer Linda M

2011-10-01

Full Text Available Abstract Background Understanding the phenotypic consequences of interactions between arthropod-borne viruses (arboviruses and their mosquito hosts has direct implications for predicting the evolution of these relationships and the potential for changes in epidemiological patterns. Although arboviruses are generally not highly pathogenic to mosquitoes, pathology has at times been noted. Here, in order to evaluate the potential costs of West Nile virus (WNV infection and resistance in a primary WNV vector, and to assess the extent to which virus-vector relationships are species-specific, we performed fitness studies with and without WNV exposure using a highly susceptible Culex pipiens mosquito colony. Specifically, we measured and compared survival, fecundity, and feeding rates in bloodfed mosquitoes that were (i infected following WNV exposure (susceptible, (ii uninfected following WNV exposure (resistant, or (iii unexposed. Results In contrast to our previous findings with a relatively resistant Cx. tarsalis colony, WNV infection did not alter fecundity or blood-feeding behaviour of Cx. pipiens, yet results do indicate that resistance to infection is associated with a fitness cost in terms of mosquito survival. Conclusions The identification of species-specific differences provides an evolutionary explanation for variability in vector susceptibility to arboviruses and suggests that understanding the costs of infection and resistance are important factors in determining the potential competence of vector populations for arboviruses.

Mosquitos vetores potenciais de dirofilariose canina na Região Nordeste do Brasil Mosquitoes potential vectors of canine heartworm in the Northeast Region from Brazil

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Silvia MM Ahid

1999-12-01

Full Text Available INTRODUÇÃO: Em alguns bairros costeiros de São Luís, Maranhão, a prevalência da dirofilariose chega a mais de 40% entre os cães domiciliados. Porém, desconhecem-se os vetores naturais, tanto lá quanto no resto do Nordeste do país. O objetivo do estudo foi identificar os prováveis vetores dessa parasitose. MÉTODOS: Realizaram-se coletas mensais de mosquitos em um bairro costeiro de São Luís, MA, de março de 1996 a maio de 1997, no peridomicílio, tendo cão e homem como iscas. Os mosquitos foram dissecados para a pesquisa de larvas da Dirofilaria immitis. RESULTADOS: Coletaram-se 1.738 mosquitos de 11 espécies. Culex quinquefasciatus, capturada todos os meses, porém menos freqüente na estação chuvosa, correspondeu a 54,5% do total, seguido de Aedes albopictus (20,3%, Aedes taeniorhynchus e Aedes scapularis (ambos 11%. Larvas de D.immitis foram encontradas em 0,1% dos Cx. quinquefasciatus e 0,5% dos Ae. taeniorhynchus. CONCLUSÕES: Ae. taeniorhynchus e Cx. quinquefasciatus foram considerados vetores potenciais da dirofilariose em São Luís. A importância local de Cx. quinquefasciatus como transmissor primário da D. immitis necessita ser melhor avaliada.INTRODUCTION: In some coastal districts of São Luís, capital of the state of Maranhão, Brazil, the prevalence of Dirofilaria immitis is more than 40% in house dogs. Natural potential vectors, as found in other areas of Northeastern Brazil, are unknown. The aim of this study was to identify probable vectors of the disease. METHODS: Mosquito catches were performed at a coastal, district Olho d'Água, in S. Luís, to look for local potential vectors. Captures were carried out monthly, from March 1996 to May 1997, outdoors, having a man and a dog as baits. Mosquitoes were dissected for D. immitis larvae. RESULTS: A total of 1,738 mosquitoes belonging to 11 species were collected. Culex quinquefasciatus, the only species collected every month, was more frequently in the dry

Distribution and larval breeding habitats of Aedes mosquito species in residential areas of northwest Ethiopia.

Science.gov (United States)

Ferede, Getachew; Tiruneh, Moges; Abate, Ebba; Kassa, Wondmeneh Jemberie; Wondimeneh, Yitayih; Damtie, Demekech; Tessema, Belay

2018-01-01

The Aedes mosquito is a vector for transmitting many arboviruses. Knowledge of the breeding habitat of this vector is vital for implementing appropriate interventions. Thus, this study was conducted to determine the breeding habitats and presence of Aedes mosquito species in the study areas. A house-to-house cross-sectional survey of Aedes mosquito breeding habitats was carried out in Metema and Humera, Ethiopia, in August 2017. All available water-holding containers present in and around houses were inspected for the presence of immature stages of Aedes mosquitoes, and they were collected and reared to the adult stage for species identification. In the larval survey, the house index, container index, and Breteau index were computed as risk indices. Of the 384 houses surveyed for the presence of Aedes mosquito larval breeding, 98 were found to be positive for larvae. During the survey, a total of 566 containers were inspected, of which 186 were found to be infested with Aedes mosquito larvae, with a container index of 32.9, a house index of 25.5, and a Breteau index of 48.4. The most common Aedes mosquito breeding habitats were discarded tires (57.5%), followed by mud pots (30.0%). Of the 1,077 larvae and pupae collected and reared, Aedes aegypti (49.3%), Ae. vittatus (6.5%), and Culex species (44.2%) were identified. Discarded tires were the most preferred breeding habitats for Aedes mosquitoes. Moreover, Ae. aegypti , the main vector of dengue and other arboviruses, was identified for the first time in this region, suggesting a high potential for arbovirus transmission in the study areas.

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

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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

Permethrin induction of multiple cytochrome P450 genes in insecticide resistant mosquitoes, Culex quinquefasciatus.

Science.gov (United States)

Gong, Youhui; Li, Ting; Zhang, Lee; Gao, Xiwu; Liu, Nannan

2013-01-01

The expression of some insect P450 genes can be induced by both exogenous and endogenous compounds and there is evidence to suggest that multiple constitutively overexpressed P450 genes are co-responsible for the development of resistance to permethrin in resistant mosquitoes. This study characterized the permethrin induction profiles of P450 genes known to be constitutively overexpressed in resistant mosquitoes, Culex quinquefasciatus. The gene expression in 7 of the 19 P450 genes CYP325K3v1, CYP4D42v2, CYP9J45, (CYP) CPIJ000926, CYP325G4, CYP4C38, CYP4H40 in the HAmCqG8 strain, increased more than 2-fold after exposure to permethrin at an LC50 concentration (10 ppm) compared to their acetone treated counterpart; no significant differences in the expression of these P450 genes in susceptible S-Lab mosquitoes were observed after permethrin treatment. Eleven of the fourteen P450 genes overexpressed in the MAmCqG6 strain, CYP9M10, CYP6Z12, CYP9J33, CYP9J43, CYP9J34, CYP306A1, CYP6Z15, CYP9J45, CYPPAL1, CYP4C52v1, CYP9J39, were also induced more than doubled after exposure to an LC50 (0.7 ppm) dose of permethrin. No significant induction in P450 gene expression was observed in the susceptible S-Lab mosquitoes after permethrin treatment except for CYP6Z15 and CYP9J39, suggesting that permethrin induction of these two P450 genes are common to both susceptible and resistant mosquitoes while the induction of the others are specific to insecticide resistant mosquitoes. These results demonstrate that multiple P450 genes are co-up-regulated in insecticide resistant mosquitoes through both constitutive overexpression and induction mechanisms, providing additional support for their involvement in the detoxification of insecticides and the development of insecticide resistance.

The haemagglutination activity in the different developmental stages and changes of this activity caused by analogues of insect hormones in two members of the Culex pipiens complex of mosquitoes

Czech Academy of Sciences Publication Activity Database

Gelbič, Ivan; Olejníček, Jiří

2004-01-01

Roč. 29, č. 4 (2004), s. 320-326 ISSN 0307-6962 R&D Projects: GA ČR GA522/02/1458; GA AV ČR KSK6005114 Institutional research plan: CEZ:AV0Z5007907 Keywords : anautogenous mosquitoes * autogenous mosquitoes * Culex pipiens molestus Subject RIV: ED - Physiology Impact factor: 1.352, year: 2004

Expression of Bacillus thuringiensis serovar. israelensis toxins in Asticcacaulis excentricus to control dipteran larvae of vectors of diseases

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Óscar Enrique Guevara

2004-01-01

Full Text Available Bacillus thuringiensis cry genes encode for a diverse group of crystal-forming proteins that exhibit insecticidal activity towards dipteran, lepidopteran and coleopteran larvae. The effectiveness of insecticides based on mosquito larvicidal B. thuringiensis strains can be enhanced by using aquatic prosthecated bacteria as alternative hosts, since they do not sink, cytoplasmic located toxins are protected f rom UV radiation and, most importantly, mosquito larvae feed on them. An Asticcacaulis excentricus reference strain was transformed with the cry1 1Aa gene from Bacillus thuringiensis serovar. israelensis. Western blot and electrophoresis were used to test recombinant protein expression; Western blot revealed a 72 kDa protein corresponding to B. thuringiensis serovar. israelensis Cry1 1 Aa. These aquatic bacte­rias toxicity achieved 50% mortality at 23 ng/mL concentration in f irst instar Culex quinquefasciatus larvae. Other bioassays indicated that recombinant A. excentricus is toxic against Aedes aegyptiand Anopheles albimanus first instar larvae. Buoyancy tests demonstrated the advantage of A. excentricus over B. thuringiensis. Key words: Asticcacaulis excentricus, Bacillus thuringiensis, prosthecated bacteria, dengue, malaria.

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

Science.gov (United States)

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

2016-01-01

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

Mosquito larval productivity in rice-fields infested with Azolla in Mvomero District, Tanzania.

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Mwingira, V S; Mayala, B K; Senkoro, K P; Rumisha, S F; Shayo, E H; Mlozi, M R S; Mboera, L E G

2009-01-01

Azolla (Salviniales: Azollaceae) is known to reduce oviposition and adult emergence of a number of mosquito species. Several species of Azolla are reportedly indigenous to Tanzania. However, the potential of Azolla as a biocontrol agent against malaria mosquitoes has not been evaluated in the country. This cross-sectional study was carried out to assess mosquito larval productivity in irrigated rice-fields infested with Azolla in Mvomero District, Tanzania. A systematic larval sampling covering all open water bodies along designed transect was carried in rice-fields. Larval density was estimated by dipping water bodies with or without Azolla. The degree of Azolla coverage was categorized as 0%, 80%. Larvae densities were categorised as low ( or = 500/m2) productivity. A total of 120 water bodies were surveyed and 105 (87.5%) had Azolla microphyla and A. pinnata at varying degrees of coverage. Of the total 105 water bodies with Azolla, 80 (76.2%) had a green Azolla mat, and 25 (23.8%) a brown Azolla mat. Eighty-eight (73.3%) of the sites were infested with anophelines and 109 (90.8%) with culicine larvae. Seventy percent of all water bodies contained anophelines and culicines in sympatric breeding, while 20.8% and 3.3% had only culicines and anophelines, respectively. The majority (82%) of mosquito breeding sites were found in area with Azolla substrate. Mosquito larva productivity was low in sites with highest (>80%) Azolla coverage. Seventy-two (81.8%) of the anopheline and 90 (82.6%) culicine breeding sites were infested with Azolla. Water bodies infested with green Azolla were more productive than those covered by brown coloured Azolla substrates for both culicines (13%) and anophelines (8%). Of the 1537 field collected larvae that hatched to adult stage, 646 (42.03%) were Anopheles gambiae s.l., 42 (2.73%) were An. funestus and 769 (50.03%) were Culex quinquefasciatus. These findings suggest that the mosquito productivity is low when the Azolla coverage is high

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.

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

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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.

Survival and swimming behavior of insecticide-exposed larvae and pupae of the yellow fever mosquito Aedes aegypti

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2014-01-01

Background The yellow fever mosquito Aedes aegypti is essentially a container-inhabiting species that is closely associated with urban areas. This species is a vector of human pathogens, including dengue and yellow fever viruses, and its control is of paramount importance for disease prevention. Insecticide use against mosquito juvenile stages (i.e. larvae and pupae) is growing in importance, particularly due to the ever-growing problems of resistance to adult-targeted insecticides and human safety concerns regarding such use in human dwellings. However, insecticide effects on insects in general and mosquitoes in particular primarily focus on their lethal effects. Thus, sublethal effects of such compounds in mosquito juveniles may have important effects on their environmental prevalence. In this study, we assessed the survival and swimming behavior of A. aegypti 4th instar larvae (L4) and pupae exposed to increasing concentrations of insecticides. We also assessed cell death in the neuromuscular system of juveniles. Methods Third instar larvae of A. aegypti were exposed to different concentrations of azadirachtin, deltamethrin, imidacloprid and spinosad. Insect survival was assessed for 10 days. The distance swam, the resting time and the time spent in slow swimming were assessed in 4th instar larvae (L4) and pupae. Muscular and nervous cells of L4 and pupae exposed to insecticides were marked with the TUNEL reaction. The results from the survival bioassays were subjected to survival analysis while the swimming behavioral data were subjected to analyses of covariance, complemented with a regression analysis. Results All insecticides exhibited concentration-dependent effects on survival of larvae and pupae of the yellow fever mosquito. The pyrethroid deltamethrin was the most toxic insecticide followed by spinosad, imidacloprid, and azadirachtin, which exhibited low potency against the juveniles. All insecticides except azadirachtin reduced L4 swimming speed and

Survival and swimming behavior of insecticide-exposed larvae and pupae of the yellow fever mosquito Aedes aegypti.

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Tomé, Hudson Vv; Pascini, Tales V; Dângelo, Rômulo Ac; Guedes, Raul Nc; Martins, Gustavo F

2014-04-24

The yellow fever mosquito Aedes aegypti is essentially a container-inhabiting species that is closely associated with urban areas. This species is a vector of human pathogens, including dengue and yellow fever viruses, and its control is of paramount importance for disease prevention. Insecticide use against mosquito juvenile stages (i.e. larvae and pupae) is growing in importance, particularly due to the ever-growing problems of resistance to adult-targeted insecticides and human safety concerns regarding such use in human dwellings. However, insecticide effects on insects in general and mosquitoes in particular primarily focus on their lethal effects. Thus, sublethal effects of such compounds in mosquito juveniles may have important effects on their environmental prevalence. In this study, we assessed the survival and swimming behavior of A. aegypti 4th instar larvae (L4) and pupae exposed to increasing concentrations of insecticides. We also assessed cell death in the neuromuscular system of juveniles. Third instar larvae of A. aegypti were exposed to different concentrations of azadirachtin, deltamethrin, imidacloprid and spinosad. Insect survival was assessed for 10 days. The distance swam, the resting time and the time spent in slow swimming were assessed in 4th instar larvae (L4) and pupae. Muscular and nervous cells of L4 and pupae exposed to insecticides were marked with the TUNEL reaction. The results from the survival bioassays were subjected to survival analysis while the swimming behavioral data were subjected to analyses of covariance, complemented with a regression analysis. All insecticides exhibited concentration-dependent effects on survival of larvae and pupae of the yellow fever mosquito. The pyrethroid deltamethrin was the most toxic insecticide followed by spinosad, imidacloprid, and azadirachtin, which exhibited low potency against the juveniles. All insecticides except azadirachtin reduced L4 swimming speed and wriggling movements. A

Evaluation of bifenthrin applications in tires to prevent Aedes mosquito breeding.

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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.

Nesting bird "host funnel" increases mosquito-bird contact rate.

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Caillouët, Kevin A; Riggan, Anna E; Bulluck, Lesley P; Carlson, John C; Sabo, Roy T

2013-03-01

Increases in vector-host contact rates can enhance arbovirus transmission intensity. We investigated weekly fluctuations in contact rates between mosquitoes and nesting birds using the recently described Nest Mosquito Trap (NMT). The number of mosquitoes per nestling increased from nesting season. Our evidence suggests the coincidence of the end of the avian nesting season and increasing mosquito abundances may have caused a "host funnel," concentrating host-seeking mosquitoes to the few remaining nestlings. The relative abundance of mosquitoes collected by the NMT suggests that significantly more Aedes albopictus (Skuse) and Culex pipiens (L.) /restuans (Theobald) sought nesting bird bloodmeals than were predicted by their relative abundances in CO2-baited Centers for Disease Control and Prevention light and gravid traps. Culex salinarius (Coquillett) and Culex erraticus Dyar and Knab were collected in NMTs in proportion to their relative abundances in the generic traps. Temporal host funnels and nesting bird host specificity may enhance arbovirus amplification and explain observed West Nile virus and St. Louis encephalitis virus amplification periods.

Impact of climate change on filarial vector, Culex quinquefasciatus and control using bacterial pesticide, spinosad

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Nareshkumar Arjunan

2014-02-01

Full Text Available Objective: To show the effect of temperature on the biology of Culex quinquefasciatus and also to show the effect of the bacterial pesticide, spinosad on developmental stages of the filarial vector. Methods: A laboratory colony of mosquito larvae was used for the larvicidal activity of temperature and spinosad. Twenty-five numbers of first, second, third, fourth instar larvae were introduced into the 500 mL glass beaker containing 250 mL of de-chlorinated water with desired temperatures (16 °C, 20 °C, 24 °C, 28 °C, 32 °C, 36 °C, similarly spinosad, at different concentrations. The development was observed for every 24 h. Results: The results showed that the rise in temperature acts as a growth inhibiting factor for mosquitoes. And no development was found in the temperature below 16 °C and above 36 °C. The hatchability was increased as the temperature was increased up to 32 °C, after which eclosion rates dropped gradually. Conclusions: 32 °C was obtained as the maximum sustainable temperature and after which the developmental rate was gradually reduced. The optimal temperature for development was lower than the temperatures at which development was quickest. The bacterial pesticide spinosad showed that it is an effective mosquito control agent and can be used for further integrated pest management programmes.

Studies on effects of Andrographis paniculata (Burm.f.) and Andrographis lineata nees (Family: Acanthaceae) extracts against two mosquitoes Culex quinquefasciatus (Say.) and Aedes aegypti (Linn.).

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

2013-03-01

To investigate the studies on effects of Andrographis paniculata (A. paniculata) (Burm.f.) and Andrographis lineata (A. lineata) nees (Family: Acanthaceae) extracts against two mosquitoes Culex quinquefasciatus (Cx. quinquefasciatus) (Say.) and Aedes aegypti (Ae. aegypti) (Linn.). The aqueous and petroleum ether extracts of two plant species, A. paniculata and A. lineate were examined against the larvae of A. aegypti (L.) and Cx. quinquefasciatus with gradually increasing concentration ie. from 50 to 200 ppm of solvent extracts and to test their activity in combination with each other. In a 24 h bioassay experiment with plant extracts, highest mortalities were recorded at 200 ppm of concentrations for leaves of A. lineta and A. paniculata individually. For combination effect, only 150 ppm of the mixture of solvent extracts of petroleum ether: aqueous (1:1) extracts showed 100% mortality after 24 h of exposure. The results show that, insecticides of plant combination is ecofriend and has better larvicidal activity compared to individual extracts. Copyright © 2013 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Blood-feeding ecology of mosquitoes in zoos.

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

2012-12-01

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

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

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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.

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

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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.

Household survey of container-breeding mosquitoes and climatic factors influencing the prevalence of Aedes aegypti (Diptera: Culicidae) in Makkah City, Saudi Arabia

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Aziz, Al Thabiany; Dieng, Hamady; Ahmad, Abu Hassan; Mahyoub, Jazem A; Turkistani, Abdulhafis M; Mesed, Hatabbi; Koshike, Salah; Satho, Tomomitsu; Salmah, MR Che; Ahmad, Hamdan; Zuharah, Wan Fatma; Ramli, Ahmad Saad; Miake, Fumio

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. 32 109 larvae representing 1st , 2nd, 3rd, and 4th stages were collected from 22 618 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. PMID:23569860

Seasonal abundance and potential of Japanese encephalitis virus infection in mosquitoes at the nesting colony of ardeid birds, Thailand.

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Changbunjong, Tanasak; Weluwanarak, Thekhawet; Taowan, Namaoy; Suksai, Parut; Chamsai, Tatiyanuch; Sedwisai, Poonyapat

2013-03-01

To investigate the abundance and seasonal dynamics of mosquitoes, and to detect Japanese encephalitis virus (JEV) in these mosquitoes at the nesting colony of ardeid birds. Mosquitoes were collected bimonthly from July 2009 to May 2010 by Centers for Disease Control. Light traps and dry ice, as a source of CO2, were employed to attract mosquitoes. Mosquitoes were first identified, pooled into groups of upto 50 mosquitoes by species, and tested for JEV infection by viral isolation and reverse transcriptase polymerase chain reaction. A total of 20 370 mosquitoes comprising 14 species in five genera were collected. The five most abundant mosquito species collected were Culex tritaeniorhynchus (95.46%), Culex vishnui (2.68%), Culex gelidus (0.72%), Anopheles peditaeniatus (0.58%) and Culex quinquefasciatus (0.22%). Mosquito peak densities were observed in July. All of 416 mosquito pools were negative for JEV. This study provides new information about mosquito species and status of JEV infection in mosquitoes in Thailand. Further study should be done to continue a close survey for the presence of this virus in the ardeid birds.

Green synthesis of silver nanoparticles for the control of mosquito vectors of malaria, filariasis, and dengue.

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Arjunan, Naresh Kumar; Murugan, Kadarkarai; Rejeeth, Chandrababu; Madhiyazhagan, Pari; Barnard, Donald R

2012-03-01

A biological method was used to synthesize stable silver nanoparticles that were tested as mosquito larvicides against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. Annona squamosa leaf broth (5%) reduced aqueous 1 mM AgNO₃ to stable silver nanoparticles with an average size of 450 nm. The structure and percentage of synthesized nanoparticles was characterized by using ultraviolet spectrophotometry, X-Ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy methods. The median lethal concentrations (LC₅₀) of silver nanoparticles that killed fourth instars of Ae. aegypti, Cx. quinquefasciatus, and An. stephensi were 0.30, 0.41, and 2.12 ppm, respectively. Adult longevity (days) in male and female mosquitoes exposed as larvae to 0.1 ppm silver nanoparticles was reduced by ~30% (p<0.05), whereas the number of eggs laid by females exposed as larvae to 0.1 ppm silver nanoparticles decreased by 36% (p<0.05).

Prevalence of Malaria, Dengue, and Chikungunya Significantly Associated with Mosquito Breeding Sites

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Islam, Mohammad Nazrul; ZulKifle, Mohammad; Sherwani, Arish Mohammad Khan; Ghosh, Susanta Kumar; Tiwari, Satyanarayan

2011-01-01

Objectives: To observe the prevalence of malaria, dengue, and chikungunya and their association with mosquito breeding sites. Methods: The study was observational and analytical. A total of 162 houses and 670 subjects were observed during the study period. One hundred forty-two febrile patients were eligible for the study. After obtaining informed consent from all febrile patients, 140 blood samples were collected to diagnose malaria, dengue, and chikungunya. Larval samples were collected by the standard protocol that follows. Correlation of data was performed by Pearson correlation test. Results: Forty-seven blood samples were found positive: 33 for chikungunya, 3 for dengue, and 11 for malaria. Fifty-one out of 224 larval samples were found positive. Out of the 51 positive samples, 37 were positive for Aedes, 12 were positive for Anopheles, and two were positive for Culex larvae. Interpretation and Conclusion: Mosquito-borne fevers, especially malaria, dengue, and chikungunya, have shown a significant relationship with mosquito breeding sites. PMID:23610486

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

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Rebekah J Kent

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

Evaluación de la actividad insecticida de un producto granulado a base de Bacillus sphaericus sobre larvas de Anopheles albimanus y Culex quinquefasciatus en condiciones experimentales

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Estrella Cárdenas

2009-01-01

Full Text Available Culex quinquefasciatus causa alergias por las picaduras y ha sido asociado con la encefalitis equina, mientras que Anopheles albimanus es vector de malaria. El objetivo fue evaluar la toxicidad de un producto granulado a base de Bacillus sphaericus sobre larvas de Culex quinquefasciatus y Anopheles albimanus. El estudio fue realizado sobre larvas de C. quinquefasciatus (Sibaté y Villavicencio y An albimanus (Cartagena y Barranquilla. Las concentraciones ensayadas de B. sphaericus fueron: 20, 40, 60, 80, 100, 120, 140, 160, 180, 200 y 500 ppm para larvas de An. albimanus y para larvas de C. quinquefasciatus fueron: 2, 4, 6, 8, 10, 12, 14 y 16 ppm. Se utilizaron 20 larvas en tres repeticiones por cada concentración del producto y el tiempo de exposición fue de 48 horas. El producto de B. sphaericus mostró alta mortalidad (entre 80 y 100% a bajas concentraciones (8 y 12 ppm para larvas de C. quinquefasciatus; mientras que para larvas de An. albimanus a concentraciones más altas (entre 40 y 200 ppm la mortalidad no superó el 50%. La CL50 Logit fue 176 ppm y la Probit fue 192 ppm de B. sphaericus para larvas de An. albimanus; mientras que para larvas de C. quinquefasciatus la CL50 Logit fue 1, 9 ppm y la Probit fue 2, 2 ppm. Se concluye que las larvas de C. quinquefasciatus fueron más susceptibles a bajas concentraciones (2 a 12 ppm de B. sphaericus, mientras que las larvas de An. albimanus mostraron alta toxicidad a concentraciones de 500 ppm.

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

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Marimuthu Govindarajan

2014-02-01

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

Landscape Effects on the Presence, Abundance and Diversity of Mosquitoes in Mediterranean Wetlands.

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David Roiz

Full Text Available Environment determines the distribution of mosquito-borne diseases in that it influences the vector-host-pathogen transmission cycle, including vector distribution, abundance and diversity. In this study, we analyse the relationship between environmental variables estimated by remote sensing and the spatial distribution (presence, abundance and diversity of seven mosquito species vectors of West Nile and other pathogens (Usutu, avian malaria and dirofilariasis in the Doñana Natural Park, Spain. Traps were distributed over an area of 54,984 ha divided into six ecological units: marshland, sand dunes, scrubland, ricefields, crops and fishponds. We collected mosquitoes once a month from up to 112 locations using BG-Sentinel traps baited with BG-lure and CO2 during March-November 2010. Hydroperiod, NDVI and Inundation surface were estimated at several resolution scales (100, 250, 500, 1000 and 2000 metres from corrected and normalized Landsat Images. We sampled 972,346 female mosquitoes, the most abundant species being Culex theileri, Ochlerotatus caspius, Culex modestus, Culex perexiguus, Culex pipiens, Anopheles atroparvus and Ochlerotatus detritus. Our results suggest that: (1 hydroperiod, inundation surface and NDVI are strongly related to the spatial distribution of mosquitoes; (2 the spatial scales used to measure these variables affected quantification of these relationships, the larger scale being more informative; (3 these relationships are species-specific; (4 hydroperiod is negatively related to mosquito presence and richness; (5 Culex abundance is positively related to hydroperiod; (6 NDVI is positively related to mosquito diversity, presence and abundance, except in the case of the two salt marsh species (Oc. caspius and Oc. detritus; and (7 inundation surfaces positively condition the abundance and richness of most species except the salt marsh mosquitoes. Remote sensing data provided reliable information for monitoring mosquito

West Nile Virus in Mosquitoes of Iranian Wetlands.

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Bagheri, Masoomeh; Terenius, Olle; Oshaghi, Mohammad Ali; Motazakker, Morteza; Asgari, Sassan; Dabiri, Farrokh; Vatandoost, Hassan; Mohammadi Bavani, Mulood; Chavshin, Ali Reza

2015-12-01

The West Nile virus (WNV) transmission cycle includes a wide range of migratory wetland birds as reservoirs, mosquitoes as biological vectors, and equines and humans as dead-end hosts. Despite the presence of potential vector species, there is no information about the existence of WNV in mosquito vectors in Iran. The Iranian West Azerbaijan Province is located in the northwestern part of Iran and has borders with Turkey, Iraq, Armenia, and the Republic of Azerbaijan. The current study was conducted to identify the wetland mosquitoes of the West Azerbaijan Province and their infection with WNV. In this study, 2143 specimens were collected, comprising 1541 adults and 602 larvae. Six species belonging to four genera were collected and identified: Anopheles maculipennis sensu lato (s.l.), Culex (Cx.) hortensis, Cx. pipiens s.l., Cx. theileri, Culiseta longiareolata, and Aedes (Ae.) (Ochlerotatus) caspius. In total, 45 pools of mosquitoes were examined. Two of the adult pools collected from the same location showed the presence of WNV in Ae. (Och.) caspius, from Sangar, Makoo County, as confirmed by PCR and sequencing. Due to the discovery of WNV in the mosquito population of the region, and the presence of wetlands and significant populations of migratory birds, the health sector should carefully monitor the factors involved in the cycle of this disease.

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

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Marta Grech

2013-09-01

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

AVALIAÇÃO DA VIRULENCIA DE BLASTOSPOROS DE Metarhizium anisopliae NO CONTROLE DE LARVAS DE CAMPO DO MOSQUITO Aedes aegypti

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Aline Teixeira Carolino

2016-11-01

Full Text Available Atualmente no Brasil, o mosquito Aedes aegypti é transmissor das arboviroses dengue, chikungunya e Zika. Não existe tratamento específico para estas doenças. A redução da população do vetor ainda é o método mais eficaz para reduzir a taxa dessas arboviroses. O presente estudo comparou a virulência de conídios e blastosporos de Metarhizium anisopliae contra larvas do mosquito A. aegypti provenientes de coletas no campo. Blastosporos foram mais virulentos para larvas, sendo observada mortalidade total das larvas em apenas 48 horas. Larvas infectadas com conídios apresentaram 100% de mortalidade no quinto dia pós-infecção. O presente estudo mostra que blastosporos apresentam grande potencial para controle de larvas de A. aegypti no campo.

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

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Luiz Gonzaga dos Santos-Neto

2008-01-01

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

Effectiveness of spinosad and temephos for the control of mosquito larvae at a tire dump in Allende, Nuevo Leon, Mexico.

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Garza-Robledo, Argentina A; Martínez-Perales, Juan F; Rodríguez-Castro, Violeta A; Quiroz-Martínez, Humberto

2011-12-01

The effectiveness of spinosad and temephos for the control of mosquito larvae was evaluated in a tire dump in Allende, Nuevo Leon, Mexico. Three groups of 12 to 17 tires located in tree shade were utilized for this study. After the larvicides were applied, samples were collected weekly from 7 randomly chosen tires. The data showed a significant difference between the larvicides and control. Under the conditions of the present study, the effectiveness of spinosad against mosquito larvae was similar to that of temephos, both being effective for up to 91 days postapplication. In addition, spinosad allowed the establishment of the mosquito predator Toxorhynchites sp.

Moussa virus: a new member of the Rhabdoviridae family isolated from Culex decens mosquitoes in Côte d'Ivoire.

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Quan, Phenix-Lan; Junglen, Sandra; Tashmukhamedova, Alla; Conlan, Sean; Hutchison, Stephen K; Kurth, Andreas; Ellerbrok, Heinz; Egholm, Michael; Briese, Thomas; Leendertz, Fabian H; Lipkin, W Ian

2010-01-01

Characterization of arboviruses at the interface of pristine habitats and anthropogenic landscapes is crucial to comprehensive emergent disease surveillance and forecasting efforts. In context of a surveillance campaign in and around a West African rainforest, particles morphologically consistent with rhabdoviruses were identified in cell cultures infected with homogenates of trapped mosquitoes. RNA recovered from these cultures was used to derive the first complete genome sequence of a rhabdovirus isolated from Culex decens mosquitoes in Côte d'Ivoire, tentatively named Moussa virus (MOUV). MOUV shows the classical genome organization of rhabdoviruses, with five open reading frames (ORF) in a linear order. However, sequences show only limited conservation (12-33% identity at amino acid level), and ORF2 and ORF3 have no significant similarity to sequences deposited in GenBank. Phylogenetic analysis indicates a potential new species with distant relationship to Tupaia and Tibrogargan virus.

Moussa virus: a new member of the Rhabdoviridae family isolated from Culex decens mosquitoes in Côte d’Ivoire

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Quan, Phenix-Lan; Junglen, Sandra; Tashmukhamedova, Alla; Conlan, Sean; Hutchison, Stephen K.; Kurth, Andreas; Ellerbrok, Heinz; Egholm, Michael; Briese, Thomas; Leendertz, Fabian H.; Ian Lipkin, W

2009-01-01

Characterization of arboviruses at the interface of pristine habitats and anthropogenic landscapes is crucial to comprehensive emergent disease surveillance and forecasting efforts. In context of surveillance campaign in and around a West African rainforest, particles morphologically consistent with rhabdoviruses were identified in cell cultures infected with homogenates of trapped mosquitoes. RNA recovered from these cultures was used to derive the first complete genome sequence of a rhabdovirus isolated from Culex decens mosquitoes in Côte d’Ivoire, tentatively named Moussa virus (MOUV). MOUV shows the classical genome organization of rhabdoviruses, with five open reading frames (ORF) in a linear order. However, sequences show only limited conservation (12–33% identity at amino acid level), and ORF2 and ORF3 have no significant similarity to sequences deposited in GenBank. Phylogenetic analysis indicates a potential new species with distant relationship to Tupaia and Tibrogargan virus. PMID:19804801

Larvicidal, Histopathological Efficacy of Penicillium daleae against Larvae of Culex quinquefasciatus and Aedes aegypti Plus Biotoxicity on Artemia nauplii a Non-target Aquatic Organism

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C. Ragavendran

2017-10-01

Full Text Available Mosquitoes can transmit the terrible diseases to human beings. Soil-borne fungal products act as potential source for low-cost chemicals, used for developing eco-friendly control agents against mosquito-vector borne diseases. The prime aim of study was to check the larvicidal potential of fungus mycelia (by ethyl acetate solvent extract from Penicillium daleae (KX387370 against Culex quinquefasciatus and Aedes aegypti and to test the toxicity of brine shrimp Artemia nauplii, by observing the physiological activity. The ethyl acetate extract of P. daleae mycelia (after 15 days from Potato dextrose broth (PDB medium revealed better result with least LC50 and LC90 values of I-IV instars larvae of Cx. quinquefasciatus (LC50 = 127.441, 129.087, 108.683, and 93.521; LC90 = 152.758, 158.169, 139.091, and 125.918 μg/ml and Ae. aegypti (LC50 = 105.077, 83.943, 97.158, and 76.513; LC90 = 128.035, 106.869, 125.640, and 104.606 μg/ml respectively. At higher concentration (1000 μg/ml of extracts, mortality begins at 18 h of exposure and attained 100% mortality after 48 h exposure. Overall, the activity was depends on the dose and time of exposure to the extracts. The stereomicroscopic and histopathological analysis of Ae. aegypti and Cx. quinquefasciatus larvae treated with mycelium ethyl acetate extract showed complete disintegration of abdominal region, particularly the midgut and caeca, loss of cuticular parts and caudal hairs. Morphological characterization of the fungi was performed and taxonomically identified through 5.8s rDNA technique. The phylogenetic analysis of rDNA sequence was carried out to find out the taxonomic and the evolutionary sketch of isolate in relation to earlier described genus Penicillium. Behavior and swimming speed alteration was analyzed together with mortality. The results of the experiment indicates that swimming behavior recorder (SBR is a appropriate tool to detect individual swimming speed of the A. nauplii organisms

Potential for Co-Infection of a Mosquito-Specific Flavivirus, Nhumirim Virus, to Block West Nile Virus Transmission in Mosquitoes

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Silvina Goenaga

2015-11-01

Full Text Available Nhumirim virus (NHUV is an insect-specific virus that phylogenetically affiliates with dual-host mosquito-borne flaviviruses. Previous in vitro co-infection experiments demonstrated prior or concurrent infection of Aedes albopictus C6/36 mosquito cells with NHUV resulted in a 10,000-fold reduction in viral production of West Nile virus (WNV. This interference between WNV and NHUV was observed herein in an additional Ae. albopictus mosquito cell line, C7-10. A WNV 2K peptide (V9M mutant capable of superinfection with a pre-established WNV infection demonstrated a comparable level of interference from NHUV as the parental WNV strain in C6/36 and C7-10 cells. Culex quinquefasciatus and Culex pipiens mosquitoes intrathoracically inoculated with NHUVandWNV, or solely withWNVas a control, were allowed to extrinsically incubate the viruses up to nine and 14 days, respectively, and transmissibility and replication of WNV was determined. The proportion of Cx. quinquefasciatus mosquitoes capable of transmitting WNV was significantly lower for the WNV/NHUV group than the WNV control at seven and nine days post inoculation (dpi, while no differences were observed in the Cx. pipiens inoculation group. By dpi nine, a 40% reduction in transmissibility in mosquitoes from the dual inoculation group was observed compared to the WNV-only control. These data indicate the potential that infection of some Culex spp. vectors with NHUV could serve as a barrier for efficient transmissibility of flaviviruses associated with human disease.

Green Nanoparticles for Mosquito Control

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Namita Soni

2014-01-01

Full Text Available Here, we have used the green method for synthesis of silver and gold nanoparticles. In the present study the silver (Ag and gold (Au nanoparticles (NPs were synthesized by using the aqueous bark extract of Indian spice dalchini (Cinnamomum zeylanicum (C. zyelanicum or C. verum J. Presl. Additionally, we have used these synthesized nanoparticles for mosquito control. The larvicidal activity has been tested against the malaria vector Anopheles stephensi and filariasis vector Culex quinquefasciatus. The results were obtained using UV-visible spectrophotometer and the images were recorded with a transmission electron microscope (TEM. The efficacy tests were then performed at different concentrations and varying numbers of hours by probit analysis. The synthesized AgNPs were in spherical shape and average sizes (11.77 nm AgNPs and 46.48 nm AuNPs. The larvae of An. stephensi were found highly susceptible to the synthesized AgNPs and AuNPs than the Cx. quinquefasciatus. These results suggest that the C. zeylanicum synthesized silver and gold nanoparticles have the potential to be used as an ideal ecofriendly approach for the control of mosquito.

Larvicidal activity and possible mode of action of four flavonoids and two fatty acids identified in Millettia pinnata seed toward three mosquito species

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Perumalsamy, Haribalan; Jang, Myung Jin; Kim, Jun-Ran; Kadarkarai, Murugan; Ahn, Young-Joon

2015-01-01

Background Aedes aegypti and Aedes albopictus and Culex pipiens pallens mosquitoes transmit dengue fever and West Nile virus diseases, respectively. This study was conducted to determine the toxicity and mechanism of action of four flavonoids and two fatty acids from Millettia pinnata (Fabaceae) seed as well as six pure fatty acids and four fatty acid esters toward third instar larvae from insecticide-susceptible C. pipiens pallens and A. aegypti as well as wild A. albopictus. Efficacy of 12 ...

EFICACIA DEL BACILLUS SPHAERICUS 2362 EN EL CONTROL DE LARVAS DE ANOPHELES PSUDOPUNCTIPENNIS (THEOBALD, 1901 Y CULEX QUINQUEFASCIATUS (SAY, 1823 EN BIOENSAYO DE LABORATORIO

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Diana Nongrados

2014-06-01

Full Text Available Se probó la actividad del Bacillus sphaericus 2362 en formulación líquida contra larvas de Anopheles pseudopunctipennis (Theobald, 1901 y Culex quinquefasciatus (Say, 1823 en bioensayos de laboratorio. Se utilizó agua destilada y agua de criadero, con concentraciones de 1 x 10 11, 1,5 x 10 11, 2,5 x 10 11, 3,9 x 10 11 esporas/mL. La población blanco se mantuvo en condiciones de laboratorio, usándose agua y flora nativa de criadero. Se vertieron dosis de 1 mL en vasos de prueba que contenían 25 larvas del II y III estadio y 150 mL de agua de criadero o agua destilada respectivamente; se usaron vasos con igual cantidad de agua y larvas como controles para cada concentración, tipo de agua y especie de larva probada. Las pruebas fueron realizadas tres veces para cada concentración, en condiciones de laboratorio. Se realizaron 12 réplicas divididas en 6 para cada especie, usándose un total de 4,800 larvas por especie. Las lecturas de la mortalidad de larvas fueron a las 12, 24, 48 y 72 h después de añadido Bacillus sphaericus. Se observó la elevada susceptibilidad de Culex quinquefasciatus a Bacillus sphaericus 2362, con una mortalidad mayor al 90% cuando se compararon los grupos tratados y controles (valor de p = 0,031 y 0,012 para cada tipo de agua respectivamente a las 48 h y con una concentración de 1,5 x 10 11 esporas/mL. Se demostró ampliamente que Anopheles pseudopunctipennis no es susceptible a Bacillus sphaericus 2362 en bioensayos de laboratorio y no se encontraron diferencias significativas en los tratamientos con diferentes tipos de agua (valor de p > 0,05.

First report of Coelomomyces santabrancae sp. nov. (Blastocladiomycetes: Blastocladiales) infecting mosquito larvae (Diptera: Culicidae) in central Brazil.

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Rueda-Páramo, M E; Montalva, C; Arruda, W; Fernandes, É K K; Luz, C; Humber, R A

2017-10-01

A project from 2013 to 2017 sought to discover pathogenic fungi and oomycetes from dipteran species that are vectors of major diseases of humans and animals in central Brazil and to begin evaluating the potential of these pathogens as potential biological control agents concentrated on mosquito larvae. Some collecting sites proved to be especially productive for pathogens of naturally occurring mosquito species and for placements of healthy sentinel larvae of Aedes aegypti in various sorts of containers in a gallery forest in the Santa Branca Ecoturismo Private Reserve of Natural Patrimony (RPPN) near Terezópolis de Goiás (GO). Collections during May-April of 2016 and February 2017 yielded a few dead mosquito larvae of an undetermined Onirion sp. (Culicidae: Sabethini) whose hemocoels contained many ovoid, thick-walled, yellow-golden to golden-brown, ovoid thick-walled resistant sporangia, 38.3±4×22.8±2.3µm, decorated by numerous, closely and randomly spaced punctations of variable size and shape. These were the first indisputable collections from Brazil of any Coelomomyces species. Comparisons of the morphology of these sporangia with those of other species of Coelomomyces, confirmed that this Brazilian fungus represented a new species that is described here as Coelomomyces santabrancae. Copyright © 2017. Published by Elsevier Inc.

The Distribution of Culex spp (Diptera: Culicidae in Selected Endemic Lymphatic Filariasis Villages in Bandung District West Java Indonesia

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Endang Puji Astuti

2017-12-01

Full Text Available Abstrak. Data entomologis terkait aspek bionomik dan distribusi nyamuk vektor lymphatic filariasis di Kabupaten Bandung masih sangat sedikit meskipun kabupaten ini sudah mengimplementasikan POPM Filariasis dari tahun 2009. Tujuan penelitian adalah mengindentifikasi spesies nyamuk potensial penular lymphatic filariasis dan habitatnya di wilayah endemis filariasis yaitu Kecamatan Majalaya, Kabupaten Bandung. Survei dilaksanakan selama 2 bulan yaitu September – Oktober 2013 di dua desa Kecamatan Majalaya. Kegiatannya adalah pencidukan larva (termasuk plotting habitat, salinitas, temperatur air, pH, penangkapan nyamuk dewasa menggunakan metode human landing (dalam dan luar rumah serta resting (dinding rumah dan kandang ternak. Hasil penangkapan nyamuk memperoleh enam spesies yang berhasil diidentifikasi. Culex quinquefasciatus dan Cx. tritaeniorhynchus adalah nyamuk yang dominan tertangkap dengan puncak gigitan antara jam 21.00-01.00 WIB. Terdapat lima tempat perkembangbiakan potensial yang teramati disekitar desa tersebut yang terdiri dari kolam ikan yang terbengkalai dan persawahan dengan salinitas 0‰, temperatur air 28,5-29°C, pH 6-7. Meskipun MHD dan MBR vektor filariasis yaitu Cx. quinquefasciatus di wilayah tersebut relatif rendah, penularan masih dapat terjadi karena didukung dengan kondisi lingkungan dan keberadaan nyamuk vektor tersebut di wilayah iniKata kunci: lymphatic filariasis; tempat perkembangbiakan; Cx. quinquefasciatus; kepadatan, BandungAbstract. Bandung district has been implemented mass drug administration (MDA program since 2009, but little is known about entomological data especially about bionomic aspects and distribution of lymphatic filariasis (LF mosquito vectors. This study was aimed to identify potential LF mosquito species and its potential breeding sites in two LF endemic villages in Majalaya, Bandung district. The observational study was conducted in September-October 2013. Mosquito larvae were collected by a

Mosquitoes Associated with Ditch-Plugged and Control Tidal Salt Marshes on the Delmarva Peninsula

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Paul T. Leisnham

2011-07-01

Full Text Available A study was conducted during the summer of 2009 (from July to September to characterize mosquito communities among different habitats in five historically ditched tidal salt marshes and three adjacent wooded areas in the E.A. Vaughn Wetland Management Area on the Maryland Delmarva Peninsula, USA. Study marshes are characteristic of Atlantic coastal salt marshes that had undergone grid ditching from the 1930s to 1950s. In the autumn of 2008 (October and November ditches were plugged near their outlets in two (‘experimental’ marshes with the aim to restore their natural tidal hydrology. The three other marshes were not plugged. Marshes were sampled from July to September in 2009 by using standard dip count method. A total of 2,457 mosquito larvae representing six species were collected on 15.4% (86/557 of all sample occasions and 399 adults representing four mosquito species were collected from landing counts. Aedes sollicitans, Anopheles bradleyi and Culex salinarius were the most common species collected in larval habitats, and Ae. sollicitans was the most common adult collected. Wooded habitats had more total mosquitoes, were also more frequently occupied by mosquitoes and had higher densities of mosquitoes than marsh habitats. Almost all larvae collected from marshes were from one experimental and one control site. The majority of larvae at the control site were Ae. sollicitans in marsh pannes while Cx. salinarius, An. bradleyi, Ae. cantator, and Ae. sollicitans were collected in high numbers from ditches at the experimental site. We found a difference in the proportion of marsh pannes occupied by Ae. sollicitans but not total mosquitoes sampled 4–5 days after spring tide events than on other occasions. Salinity measures of 42 larval habitats showed lower median salinity in mosquito-occupied habitats (11.5 ppt than unoccupied habitats (20.1 ppt, and in habitats in wooded areas followed by ditches and pannes in marsh areas. The results of

Effects of combination of leaf resources on competition in container mosquito larvae.

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Reiskind, M H; Zarrabi, A A; Lounibos, L P

2012-08-01

Resource diversity is critical to fitness in many insect species, and may determine the coexistence of competitive species and the function of ecosystems. Plant material provides the nutritional base for numerous aquatic systems, yet the consequences of diversity of plant material have not been studied in aquatic container systems important for the production of mosquitoes. To address how diversity in leaf detritus affects container-inhabiting mosquitoes, we examined how leaf species affect competition between two container inhabiting mosquito larvae, Aedes aegypti and Aedes albopictus, that co-occur in many parts of the world. We tested the hypotheses that leaf species changes the outcome of intra- and interspecific competition between these mosquito species, and that combinations of leaf species affect competition in a manner not predictable based upon the response to each leaf species alone (i.e. the response to leaf combinations is non-additive). We find support for our first hypothesis that leaf species can affect competition, evidence that, in general, leaf combination alters competitive interactions, and no support that leaf combination impacts interspecific competition differently than intraspecific competition. We conclude that combinations of leaves increase mosquito production non-additively such that combinations of leaves act synergistically, in general, and result in higher total yield of adult mosquitoes in most cases, although certain leaf combinations for A. albopictus are antagonistic. We also conclude that leaf diversity does not have a different effect on interspecific competition between A. aegypti and A. albopictus, relative to intraspecific competition for each mosquito.

Laboratory evaluation of ethyl acetate and chloroform: methanol (1:1 v/v extract of Swietenia mahagoni leaf against Japanese Encephalitis vector Culex vishuni group

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Utpal Adhikari

2012-12-01

Full Text Available Objective: To study the larvicidal activity of a furniture tree Swietenia mahagoni L. (S. mahagoni against mosquito Culex Vishnui group. Methods: Different concentrations of crude, chloroform: methanol (1:1 v/v and ethyl acetate solvent extracts of S. mahagoni mature leaves were treated against Cx. vishnui group larvae. Results: Five graded concentrations (0.05%, 0.10%, 0.20%, 0.30% and 0.40% of crude extract of mature leaves and five graded concentrations (10 ppm, 20 ppm, 30 ppm, 40 ppm and 50 ppm of chloroform: methanol (1:1 v/v and ethyl acetate solvent extracts showed significant (P<0.05 larval mortalities. LC50, LC90 values were calculated at 24 h, 48 h and 72 h of exposures. Adult Cx. vishnui group mosquitoes exposed to burning coils prepared from S. mahagoni mature leaves showed smoke repellency and toxicity up to 4 h. Conclusions: This study was a pioneer attempt to establish S. mahagoni as an effective mosquito larvicide.

Evolution determines how global warming and pesticide exposure will shape predator-prey interactions with vector mosquitoes.

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Tran, Tam T; Janssens, Lizanne; Dinh, Khuong V; Op de Beeck, Lin; Stoks, Robby

2016-07-01

How evolution may mitigate the effects of global warming and pesticide exposure on predator-prey interactions is directly relevant for vector control. Using a space-for-time substitution approach, we addressed how 4°C warming and exposure to the pesticide endosulfan shape the predation on Culex pipiens mosquitoes by damselfly predators from replicated low- and high-latitude populations. Although warming was only lethal for the mosquitoes, it reduced predation rates on these prey. Possibly, under warming escape speeds of the mosquitoes increased more than the attack efficiency of the predators. Endosulfan imposed mortality and induced behavioral changes (including increased filtering and thrashing and a positional shift away from the bottom) in mosquito larvae. Although the pesticide was only lethal for the mosquitoes, it reduced predation rates by the low-latitude predators. This can be explained by the combination of the evolution of a faster life history and associated higher vulnerabilities to the pesticide (in terms of growth rate and lowered foraging activity) in the low-latitude predators and pesticide-induced survival selection in the mosquitoes. Our results suggest that predation rates on mosquitoes at the high latitude will be reduced under warming unless predators evolve toward the current low-latitude phenotype or low-latitude predators move poleward.

The use of annual killifish in the biocontrol of the aquatic stages of mosquitoes in temporary bodies of fresh water; a potential new tool in vector control

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Adrias Araceli Q

2010-05-01

Full Text Available Abstract Background Mosquitoes that breed in temporary pools in remote areas that dry up seasonally are especially difficult to control through chemical or biological means. The annual killifish has been suggested as a means of eradicating the aquatic stages of mosquitoes in transient pools because they can maintain permanent populations in such habitats by undergoing suspended animation or diapause during the embryonic stages to survive periodic drought. However, very little is known about the predatory activity of annual killifish and their usefulness in mosquito control. Results The annual killifish, Nothobranchius guentheri, native to Tanzania, was used in this investigation. Food preference was tested under laboratory conditions by feeding juvenile killifish with 2nd instar mosquito larvae of Culex quinquefasciatus in the presence of alternative food sources, such as rotifers and chironomid larvae. Semi-field tests were conducted by introduction of hibernating killifish embryos and juvenile fish to artificial ponds in an outdoor open environment that allowed natural oviposition of Cx. quinquefasciatus. Food preference studies show that N. guentheri preferred to prey on mosquito larvae than either chironomid or rotifers. When hibernating killifish embryos were added to ponds simultaneously with the addition of freshwater, the embryos hatched and fed on mosquito larval population resulting in complete elimination of the immature stages. The introduction of juvenile fish to ponds with high density of mosquito larvae resulted in total eradication of the mosquito population due to predation by fish. Complete biocontrol of the mosquito larval population was achieved in the presence of 3 fish per m2 of pond surface area. Conclusions The annual killifish provides yet another tool that may be employed in the eradication diseases carried by mosquitoes through vector control, particularly in temporary bodies of freshwater. The fish can be conveniently

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

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N. SONI, S. PRAKASH

2012-05-01

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

Effects of an aqueous extract of Azadirachta indica on the groCulex ...

African Journals Online (AJOL)

The neem tree Azadirachta indica Juss (Meliaceae) is one of the most studied plant species for pest control, including mosquitoes. However, the effect of aqueous neem seed extracts (ANSE) on each of the 4 instars of mosquito Culex quinquefasciatus Say (Diptera: Culicidae) is unknown. In order to determine the effect of ...

Alternative methodologies in the integrated control of urban mosquito larvae: water surface obliteration techniques Metodologías alternativas en el control integrado de larvas de mosquitos urbanos: técnicas de obliteración de lámina de agua Metodologias alternativas no controlo integrado de larvas de mosquitos nas áreas urbanas: técnicas de obliteração da superfície da água

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Roger Eritja

2012-12-01

Full Text Available The public health risk associated to mosquitoes has increased in Spain by the introduction of the Asian Tiger Mosquito (Aedes albopictus which is a well-known disease vector. Integrated control methodologies basically rely on larviciding by weekly applications of microbial biocides that have no residual effect. In some special cases, such as swimming pools in abandoned estates, this weekly schedule cannot be achieved due to difficulties of access and operational reasons. In these circumstances, there are no appropriate biocidal options except for Insect Growth Regulators (IGR, which do not provide more than a few weeks of residual efficiency. We present here the practical application of a well-known technique for controlling mosquito larvae in urban environments by altering the water/air interface. The adding to the water surface of a thick layer of beads made from inert, floating materials is described. The layer of beads impedes oviposition and adversely affects the breathing of the larvae. This technique avoids the regular application of chemical pesticides, as well as providing improved sustainability and higher efficiency times. Caution notes and side effects are also discussed.Los mosquitos son un riesgo relevante para la salud pública que se ha visto incrementado con la llegada de Aedes albopictus, el mosquito tigre, potencial transmisor de varias enfermedades. El método de elección para su control es la eliminación de las larvas acuáticas mediante biocidas de origen biológico, que se realiza semanalmente debido a su nula persistencia. En determinados puntos donde esta periodicidad no puede mantenerse, como piscinas en fincas abandonadas, no existen opciones biocidas adecuadas más residuales exceptuando los inhibidores del crecimiento, que sin embargo no suelen proporcionar una residualidad superior a unas pocas semanas (de dos a cuatro. Se presenta la aplicación práctica de una técnica de control de larvas de mosquito en medios

Interactions between the invasive Burmese python, Python bivittatus Kuhl, and the local mosquito community in Florida, USA.

Science.gov (United States)

Reeves, Lawrence E; Krysko, Kenneth L; Avery, Michael L; Gillett-Kaufman, Jennifer L; Kawahara, Akito Y; Connelly, C Roxanne; Kaufman, Phillip E

2018-01-01

The Burmese python, Python bivittatus Kuhl, is a well-established invasive species in the greater Everglades ecosystem of southern Florida, USA. Most research on its ecological impacts focuses on its role as a predator and its trophic interactions with native vertebrate species, particularly mammals. Beyond predation, there is little known about the ecological interactions between P. bivittatus and native faunal communities. It is likely that established populations of P. bivittatus in southern Florida serve as hosts for native mosquito communities. To test this concept, we used mitochondrial cytochrome c oxidase subunit I DNA barcoding to determine the hosts of blood fed mosquitoes collected at a research facility in northern Florida where captive P. bivittatus and Argentine black and white tegu, Salvator merianae (Duméril and Bibron), are maintained in outdoor enclosures, accessible to local mosquitoes. We recovered python DNA from the blood meals of three species of Culex mosquitoes: Culex erraticus (Dyar and Knab), Culex quinquefasciatus Say, and Culex pilosus (Dyar and Knab). Culex erraticus conclusively (P = 0.001; Fisher's Exact Test) took more blood meals from P. bivittatus than from any other available host. While the majority of mosquito blood meals in our sample were derived from P. bivittatus, only one was derived from S. merianae. These results demonstrate that local mosquitoes will feed on invasive P. bivittatus, a recently introduced host. If these interactions also occur in southern Florida, P. bivittatus may be involved in the transmission networks of mosquito-vectored pathogens. Our results also illustrate the potential of detecting the presence of P. bivittatus in the field through screening mosquito blood meals for their DNA.

Interactions between the invasive Burmese python, Python bivittatus Kuhl, and the local mosquito community in Florida, USA.

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Lawrence E Reeves

Full Text Available The Burmese python, Python bivittatus Kuhl, is a well-established invasive species in the greater Everglades ecosystem of southern Florida, USA. Most research on its ecological impacts focuses on its role as a predator and its trophic interactions with native vertebrate species, particularly mammals. Beyond predation, there is little known about the ecological interactions between P. bivittatus and native faunal communities. It is likely that established populations of P. bivittatus in southern Florida serve as hosts for native mosquito communities. To test this concept, we used mitochondrial cytochrome c oxidase subunit I DNA barcoding to determine the hosts of blood fed mosquitoes collected at a research facility in northern Florida where captive P. bivittatus and Argentine black and white tegu, Salvator merianae (Duméril and Bibron, are maintained in outdoor enclosures, accessible to local mosquitoes. We recovered python DNA from the blood meals of three species of Culex mosquitoes: Culex erraticus (Dyar and Knab, Culex quinquefasciatus Say, and Culex pilosus (Dyar and Knab. Culex erraticus conclusively (P = 0.001; Fisher's Exact Test took more blood meals from P. bivittatus than from any other available host. While the majority of mosquito blood meals in our sample were derived from P. bivittatus, only one was derived from S. merianae. These results demonstrate that local mosquitoes will feed on invasive P. bivittatus, a recently introduced host. If these interactions also occur in southern Florida, P. bivittatus may be involved in the transmission networks of mosquito-vectored pathogens. Our results also illustrate the potential of detecting the presence of P. bivittatus in the field through screening mosquito blood meals for their DNA.

Using wintergreen oil for mounting mosquito larvae: a safer alternative to xylene.

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Koay, J B; Natasya, N N; Nashithatul, Mag; Ihsanuddin, R; Salleh, F M; Azil, A H

2016-01-01

Permanent mounting of fourth instar mosquito larvae is essential for identifying Aedes spp. This procedure requires extensive exposure to xylene, a clearing agent in the mounting process. We investigated wintergreen oil as a substitute for xylene. Five hundred larvae were mounted on slides to evaluate shrinkage or expansion of specimens after clearing using xylene or wintergreen oil. We examined the ventral brush and siphonal hair tufts for species identification and for preservation of morphological characteristics after clearing specimens in xylene or wintergreen oil. Shrinkage of the length of whole larvae and width of the head, thorax and abdomen after mounting was significantly greater after clearing with xylene than with wintergreen oil. The length of the comb scale nearest the ventral brush was similar for both clearing agents. The clarity of the specimens after mounting was improved by clearing with wintergreen oil, but the integrity of the ventral brush and siphonal hair tufts were similar for both clearing agents.

Zika virus: An updated review of competent or naturally infected mosquitoes.

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Epelboin, Yanouk; Talaga, Stanislas; Epelboin, Loïc; Dusfour, Isabelle

2017-11-01

Zika virus (ZIKV) is an arthropod-borne virus (arbovirus) that recently caused outbreaks in the Americas. Over the past 60 years, this virus has been observed circulating among African, Asian, and Pacific Island populations, but little attention has been paid by the scientific community until the discovery that large-scale urban ZIKV outbreaks were associated with neurological complications such as microcephaly and several other neurological malformations in fetuses and newborns. This paper is a systematic review intended to list all mosquito species studied for ZIKV infection or for their vector competence. We discuss whether studies on ZIKV vectors have brought enough evidence to formally exclude other mosquitoes than Aedes species (and particularly Aedes aegypti) to be ZIKV vectors. From 1952 to August 15, 2017, ZIKV has been studied in 53 mosquito species, including 6 Anopheles, 26 Aedes, 11 Culex, 2 Lutzia, 3 Coquillettidia, 2 Mansonia, 2 Eretmapodites, and 1 Uranotaenia. Among those, ZIKV was isolated from 16 different Aedes species. The only species other than Aedes genus for which ZIKV was isolated were Anopheles coustani, Anopheles gambiae, Culex perfuscus, and Mansonia uniformis. Vector competence assays were performed on 22 different mosquito species, including 13 Aedes, 7 Culex, and 2 Anopheles species with, as a result, the discovery that A. aegypti and Aedes albopictus were competent for ZIKV, as well as some other Aedes species, and that there was a controversy surrounding Culex quinquefasciatus competence. Although Culex, Anopheles, and most of Aedes species were generally observed to be refractory to ZIKV infection, other potential vectors transmitting ZIKV should be explored.

Zika virus: An updated review of competent or naturally infected mosquitoes

Science.gov (United States)

Talaga, Stanislas; Epelboin, Loïc; Dusfour, Isabelle

2017-01-01

Zika virus (ZIKV) is an arthropod-borne virus (arbovirus) that recently caused outbreaks in the Americas. Over the past 60 years, this virus has been observed circulating among African, Asian, and Pacific Island populations, but little attention has been paid by the scientific community until the discovery that large-scale urban ZIKV outbreaks were associated with neurological complications such as microcephaly and several other neurological malformations in fetuses and newborns. This paper is a systematic review intended to list all mosquito species studied for ZIKV infection or for their vector competence. We discuss whether studies on ZIKV vectors have brought enough evidence to formally exclude other mosquitoes than Aedes species (and particularly Aedes aegypti) to be ZIKV vectors. From 1952 to August 15, 2017, ZIKV has been studied in 53 mosquito species, including 6 Anopheles, 26 Aedes, 11 Culex, 2 Lutzia, 3 Coquillettidia, 2 Mansonia, 2 Eretmapodites, and 1 Uranotaenia. Among those, ZIKV was isolated from 16 different Aedes species. The only species other than Aedes genus for which ZIKV was isolated were Anopheles coustani, Anopheles gambiae, Culex perfuscus, and Mansonia uniformis. Vector competence assays were performed on 22 different mosquito species, including 13 Aedes, 7 Culex, and 2 Anopheles species with, as a result, the discovery that A. aegypti and Aedes albopictus were competent for ZIKV, as well as some other Aedes species, and that there was a controversy surrounding Culex quinquefasciatus competence. Although Culex, Anopheles, and most of Aedes species were generally observed to be refractory to ZIKV infection, other potential vectors transmitting ZIKV should be explored. PMID:29145400

Single-step biological fabrication of colloidal silver nanoparticles using Hugonia mystax: larvicidal potential against Zika virus, dengue, and malaria vector mosquitoes.

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Govindarajan, Marimuthu; Kadaikunnan, Shine; Alharbi, Naiyf S; Benelli, Giovanni

2017-11-01

Mosquito control is facing key challenges, including outbreaks of new arbovirus threats. We proposed an eco-friendly synthesis of silver nanoparticles (AgNPs) employing a low-cost extract of Hugonia mystax. AgNPs were specified by UV, XRD, FTIR and EDX spectroscopy, SEM and TEM. AgNPs were more toxic to Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus larvae (LC 50 : 14.45, 15.86, and 17.46 μg/mL) if compared to aquatic biocontrol organisms Gambusia affinis, Diplonychus indicus, and Anisops bouvieri (LC 50 : 2567.15, 1075.16, and 829.63 μg/ml). Overall, we shed light on the mosquito larvicidal efficacy of H. mystax, a possible biological resource for low-cost fabrication of AgNPs.

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

Science.gov (United States)

Nagappan, Raja

2012-09-01

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

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

2018-05-01

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.

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

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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

West Nile virus infection rates in Culex nigripalpus (Diptera: Culicidae) do not reflect transmission rates in Florida.

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Rutledge, C Roxanne; Day, Jonathan F; Lord, Cynthia C; Stark, Lillian M; Tabachnick, Walter J

2003-05-01

We describe the first documented field transmission of West Nile (WN) virus by a North American mosquito. WN was first detected in northern Florida in 2001. An intensive mosquito trapping and surveillance program was conducted in this region for four nights to assess mosquito transmission of WN. Four mosquito traps, each with a single sentinel chicken, were placed at five different locations on each of four nights. A total of 11,948 mosquitoes was collected, and 14 mosquito pools were found to contain WN, giving a minimum infection rate between 1.08 and 7.54 per 1,000. Only one of the 80 sentinel chickens seroconverted to WN, demonstrating a single mosquito transmission event during the study and a mosquito transmission rate of between 0.8 and 1 per 1,000. Culex nigripalpus Theobald was responsible for WN transmission to the sentinel chicken, although both Cx. nigripalpus and Culex quinquefasciatus Say were found infected with WN. Mosquito transmission rates are reported in this study for the first time for a WN outbreak. This information is essential to determine risk of human and animal infection.

Laboratory evaluation of Mesocyclops annulatus (Wierzejski, 1892 (Copepoda: Cyclopidea as a predator of container-breeding mosquitoes in Argentina

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María V Micieli

2002-09-01

Full Text Available In laboratory bioassays we tested the predatory capacity of the copepod Mesocyclops annulatus on Aedes aegypti and Culex pipiens larvae. A single adult female of M. annulatus caused 51.6% and 52.3% mortality of 50 first instar larvae of Ae. aegypti and Cx. pipiens respectively, in a 72 h test period. When alternative food was added to the containers, mortality rates declined to 16% and 10.3% for Ae. aegypti and Cx. pipiens respectively. When 50 first instar larvae of each of the two mosquito species tested were placed together with a single adult female of M. annulatus, mortality rates were 75.5% for Ae. aegypti larvae and 23.5% for Cx. pipiens larvae in a three day test period. Different density of adult females of M. annulatus ranged from 5 to 25 females produced mortality rates of Ae. aegypti first instar larvae from 50% to 100% respectively. When a single adult female of M. annulatus was exposed to an increasing number of first-instar Ae. aegypti larvae ranging from 10 to 100, 100% mortality was recorded from 1 to 25 larvae, then mortality declined to 30% with 100 larvae. The average larvae killed per 24 h period by a single copepod were 29.

Research Note 2: Egg raft density and feeding preference of Culex ...

African Journals Online (AJOL)

... useful for estimating the number of eggs in a culicine egg raft, making a decision on larvae food preference and using the easily available table sugar instead of the more expensive sucrose in adult rearing. Keywords:mosquito eggs, mosquito larvae, culicine mosquito, egg raft density. Nigerian Journal of Parasitology Vol.

S argassum muticum-synthesized silver nanoparticles: an effective control tool against mosquito vectors and bacterial pathogens.

Science.gov (United States)

Madhiyazhagan, Pari; Murugan, Kadarkarai; Kumar, Arjunan Naresh; Nataraj, Thiyagarajan; Dinesh, Devakumar; Panneerselvam, Chellasamy; Subramaniam, Jayapal; Mahesh Kumar, Palanisamy; Suresh, Udaiyan; Roni, Mathath; Nicoletti, Marcello; Alarfaj, Abdullah A; Higuchi, Akon; Munusamy, Murugan A; Benelli, Giovanni

2015-11-01

Mosquito-borne diseases represent a deadly threat for millions of people worldwide. Furthermore, pathogens and parasites polluting water also constitute a severe plague for populations of developing countries. In this research, silver nanoparticles (AgNP) were synthesized using the aqueous extract of the seaweed Sargassum muticum. The production of AgNP was confirmed by surface plasmon resonance band illustrated in UV-vis spectrophotometry. AgNP were characterized by FTIR, SEM, EDX, and XRD analyses. AgNP were mostly spherical in shape, crystalline in nature, with face-centered cubic geometry, and mean size was 43-79 nm. Toxicity of AgNP was assessed against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. In laboratory, AgNP were highly toxic against larvae and pupae of the three mosquito species. Maximum efficacy was observed against A. stephensi larvae, with LC50 ranging from 16.156 ppm (larva I) to 28.881 ppm (pupa). In the field, a single treatment with AgNP (10 × LC50) in water storage reservoirs was effective against the three mosquito vectors, allowing complete elimination of larval populations after 72 h. In ovicidal experiments, egg hatchability was reduced by 100% after treatment with 30 ppm of AgNP. Ovideterrence assays highlighted that 10 ppm of AgNP reduced oviposition rates of more than 70% in A. aegypti, A. stephensi, and C. quinquefasciatus (OAI = -0.61, -0.63, and -0.58, respectively). Antibacterial properties of AgNP were evaluated against Bacillus subtilis, Klebsiella pneumoniae, and Salmonella typhi using the agar disk diffusion and minimum inhibitory concentration protocol. AgNP tested at 50 ppm evoked growth inhibition zones larger than 5 mm in all tested bacteria. Overall, the chance to use S. muticum-synthesized AgNP for control of mosquito vectors seems promising since they are effective at low doses and may constitute an advantageous alternative to build newer and safer mosquito control tools. This is the first

Turbidity thrives the efficacy of the eastern mosquitofish and the Spanish toothcarp as mosquito control agents

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Sergi Vargas

2015-11-01

Full Text Available Eutrophication is one of the major threats to freshwater biodiversity with important ramifications for ecosystem functions and the benefits they provide to society. One of the first visible effects of eutrophication is elevated water turbidity, which reduces the aesthetic appeal of water bodies. Also, turbidity limits organisms’ response to visual cues, which can alter species interactions including prey-consumer relationships. For visual predators, such as most fish, turbidity acts as anti-predation refugee for their prey. This loss of the top-down control can trigger multi-trophic impacts with potential collateral effects such as the proliferation of pests. The mosquito Culex pipiens is one of the most common mosquito species in eutrophic waters where its larvae are favoured by the organic matter enrichment (e.g. microalgae, bacteria and other fine particles. Since mosquitoes are annoying insects for public, and some species are vectors of diseases, mosquito control is a major interest for administration. In many temperate countries, including Spain, this led to the introduction of the eastern mosquitofish (Gambusia holbrooki, one of the world’s 100 worst invasive species. However, this practice is now illegal after the enforcement of new legislation. In an attempt to demonstrate that native species can be as effective as G. holbrooki for mosquito control, this study examined the efficacy of G. holbrooki and the endangered Spanish toothcarp (Aphanius iberus. Specifically, we compared the voracity and total biomass of larvae consumed by the two fish species along a turbidity gradient, simulating phytoplankton and fine sediment levels observed in eutrophic waters. Our results support the replacement of G. holbrooki with A. iberus for mosquito larval control despite indicate the major voracity of the former in all treatments. In conclusion, this study suggests that the introduction of G. holbrooki was perhaps unnecessary for mosquito

Larvicidal effects of aqueous extracts of Balanites aegyptiaca (desert ...

African Journals Online (AJOL)

The effect of aqueous extracts of the fruit pulp, seed kernel, roots, bark, and leaves of Balanites aegyptiaca Del. (Zygophyllacea) against the larvae of the Culex pipens mosquito was investigated. Early fourth instars larvae of C. pipiens mosquitoes were exposed, for up to three days, to a dilution of 0, 0.1, 0.25, 0.5, 1.0, and ...

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.

Spatial and temporal distribution of mosquitoes in underground storm drain systems in Orange County, California.

Science.gov (United States)

Su, Tianyun; Webb, James P; Meyer, Richard P; Mulla, Mir S

2003-06-01

Underground storm drain systems in urban areas of Orange County include thousands of miles of gutters and underground pipelines, plus hundreds of thousands of catch basins and manhole chambers, all of which drain runoff water from residential, business and commercial establishments as well as highways and streets. These systems serve as major developmental and resting sites for anthropophilic and zoophilic mosquitoes. Investigations on spatial and temporal distribution of mosquitoes in these systems were conducted during November 1999 to October 2001. Immature mosquitoes were sampled by dipper or dipping net and adult mosquitoes by non-attractive CDC traps in manhole chambers, catch basins and a large drain. Culex quinquefasciatus Say prevailed at all 15 structures of the study in 4 cities of Orange County as the predominant species (> 99.9%). Larvae and pupae were present from April to October, peaking from May to September. The population density of adults was the lowest in February with 2 peaks of abundance occurring from May to July and from September to October. Manhole chambers and catch basins harbored more mosquitoes than did the large drain. Minimum and maximum temperatures during a 24 h sampling period was an important factor influencing adult mosquito activity and catches; more mosquitoes were caught in traps when it was warmer, especially when the minimum temperatures were higher. The proportion of females to males in general increased during winter and early spring an ddeclined during summer. The proportion of gravid females to empty females was higher during the winter than in summer. Other dipteran taxa such as psychodid moth flies and chironomid midges exhibited somewhat similar seasonal patterns as did mosquito populations. Average water temperature was relatively stable throughout the year, and water quality in underground drain systems was characterized by low dissolved oxygen, coupled with above normal electrical conductivity and salinity levels

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.

Biological and biomatrial effects of gamma radiation on the mosquito Culex Pipiens L. Vol. 4.

Energy Technology Data Exchange (ETDEWEB)

Wakid, A M; Shoman, A A [Applied Biology Dept., NRC, Atomic Energy Authority. Cairo (Egypt); Amin, A H; Kansouh, A H [Plant Protection Dept., FaC. of Agriculture, Ain Shams Univ. Cairo (Egypt)

1996-03-01

The mosquito, Culex Pipiens L. Was irradiated in the pupal stage with three gamma doses (40, 60 and 80 Gy). The effect of irradiation on the biology and ovarian development of the adult stage were assayed in comparison with a non-irradiated control group. The results showed that the gamma doses used decreased significantly adult emergence and increased malformations, while the sex ratio was not affected. fecundity of irradiated females was severely affected at 40 and 60 Gy, and 80 Gy produced in fecund females. Egg hatch ability was severely affected when males were irradiated at all doses. The gamma doses used decreased the number of ovarioles that reached the 5 th stage of christopher cycle. these ovarioles failed to produce mature eggs normally. The size of the irradiated female ovary was decreased either in length or in width at all doses used particularly at 80 Gy where the ovarian development was completely stopped on the first day of feeding. 6 figs.

Isolation and characterization of halotolerant bacteria associated with the midgut of Culex quinquefasciatus Say (Diptera: Culicidae).

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Reegan, Appadurai Daniel; Paulraj, Michael Gabriel; Ignacimuthu, Savarimuthu

2013-11-01

We show for the first time that the midgut of Culex quinquefasciatus (Say) mosquito larvae harbors halotolerant bacteria. The midgut from field collected Cx. quinquefasciatus larvae were dissected under aseptic conditions, homogenized and plated on LB agar medium with 2% (w/v) NaCl. Two different colonies were successfully isolated and bacterial isolates were identified by 16S rRNA sequences. The halotolerant bacterial isolates were: Halobacillus litoralis (CxH1) and Staphylococcus cohnii (CxH2). The gene sequence of these isolates has been deposited in GenBank (JN016804 and JN183986). These halotolerant bacteria grew in the absence of salt (0%) as well as in the presence of relatively high salt concentrations in culture medium (20%), and grew best in the presence of 8-10% (w/v) NaCl. H. litoralis and S. cohnii showed growth up to 18 and 20% (w/v) NaCl, respectively. Optimum growth temperatures for both the bacteria were between 30-37 degrees C. H. litoralis was resistant to the antibiotics oxacillin, penicillin, polymixin and S. cohnii was resistant to the antibiotic oxacillin.

Larvicidal potential of some plants from West Africa against Culex quinquefasciatus (Say) and Anopheles gambiae Giles (Diptera: Culicidae).

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Azokou, Alain; Koné, Mamidou W; Koudou, Benjamin G; Tra Bi, Honora F

2013-01-01

Mosquitoes increased resistance to insecticides, and environmental concerns about the use of insecticides, pose a major challenge in the search for new molecules to deplete and incapacitate mosquito populations. Plants are the valuable source as practices consisting in exploiting plant materials as repellents, and are still in wide use throughout developing countries. The aim of the present study was to screen plants from Cτte d'Ivoire for larvicidal activity against mosquitoes. Resistant and sensitive larvae (III and IV instar) of Anopheles gambiae and Culex quinquefasciatus were exposed to crude ethanol extracts (90%) of 45 plants and viability observed after 30 min, 6, 12 and 24 h postincubation. After partition of active extracts, each fraction (hexane and chloroform washed with NaCl 1%, tannins and aqueous) was tested using the same protocol at various concentrations (1000- 31.2 ppm). Of 49 extracts tested, 7 exhibited high potential (LC50 = 80 to 370 ppm) against resistant and sensitive III and IV instar larvae of An. gambiae and Cx. quinquefasciatus. These extracts were from Cissus populnea, Cochlospermum planchonii, Heliotropium indicum, Phyllanthus amarus, Vitex grandifolia and Alchornea cordifolia. However, three most active plant species (LC50 = 80- 180 ppm) were Cs. populnea, Cm. planchonii and P. amarus Their hexane and chloroform fractions showed high larvicidal activity. This study demonstrated that plants from Cτte d'Ivoire have a real potential for malaria, yellow fever, filarial and dengue vector control. Those could be used as sources or provide lead compounds for the development of safe plant-based biocides.

Laboratory Evaluations of the Fractions Efficacy of Annona senegalensis (Annonaceae) Leaf Extract on Immature Stage Development of Malarial and Filarial Mosquito Vectors.

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Lame, Younoussa; Nukenine, Elias Nchiwan; Pierre, Danga Yinyang Simon; Elijah, Ajaegbu Eze; Esimone, Charles Okechukwu

2015-12-01

Within the framework to control mosquitoes, ovicidal, larvicidal and pupicidal activity of Annona senegalensis leaf extract and its 4 fractions against Anopheles gambiae and Culex quinquefasciatus were evaluated in the laboratory conditions. Ovicidal test was performed by submitting at least 100 eggs of mosquitoes to 125, 250, 500, 1000 and 2000 ppm concentrations, while larvicidal and pupicidal effects were assessed by submitting 25 larvae or pupae to the concentrations of 2500, 1250, 625 and 312.5 ppm of plant extract or fractions of A. senegalensis. The eggs of An. gambiae were most affected by N-hexane (0.00% hatchability) and chloroform (03.67% hatchability) fractions compared to Cx. quinquefasciatus where at least 25 % hatchability were recorded at 2000 ppm. For larvicidal test, N-hexane (LC50= 298.8 ppm) and chloroform (LC50= 418.3 ppm) fractions were more effective than other fractions on An. gambiae larvae while, a moderate effectiveness was also observed with N-hexane (LC50= 2087.6 ppm), chloroform (LC50= 9010.1 ppm) fractions on Cx. quinquefasciatus larvae. The highest mortality percent of the pupae were also recorded with N-hexane and chloroform fractions on An. gambiae at 2500 ppm. As for Cx. quinquefasciatus only 50 % and 36 % mortality were recorded with N-hexane and chloroform fractions respectively. The extract of A. senegalensis was toxic on immature stage of mosquito species tested. By splitting methanolic crude extract, only N-hexane and chloroform fractions were revealed to possess a mosquitocidal effects and could be considered and utilized for future immature mosquito vectors control.

Laboratory Evaluations of the Fractions Efficacy of Annona senegalensis (Annonaceae Leaf Extract on Immature Stage Development of Malarial and Filarial Mosquito Vectors

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Younoussa Lame

2015-10-01

Full Text Available Background: Within the framework to control mosquitoes, ovicidal, larvicidal and pupicidal activity of Annona senegalensis leaf extract and its 4 fractions against Anopheles gambiae and Culex quinquefasciatus were evaluated in the laboratory conditions.Methods: Ovicidal test was performed by submitting at least 100 eggs of mosquitoes to 125, 250, 500, 1000 and 2000 ppm concentrations, while larvicidal and pupicidal effects were assessed by submitting 25 larvae or pupae to the concentrations of 2500, 1250, 625 and 312.5 ppm of plant extract or fractions of A. senegalensis.Results: The eggs of An. gambiae were most affected by N-hexane (0.00% hatchability and chloroform (03.67% hatchability fractions compared to Cx. quinquefasciatus where at least 25 % hatchability were recorded at 2000 ppm. For larvicidal test, N-hexane (LC50= 298.8 ppm and chloroform (LC50= 418.3 ppm fractions were more effective than other fractions on An. gambiae larvae while, a moderate effectiveness was also observed with Nhexane (LC50= 2087.6 ppm, chloroform (LC50= 9010.1 ppm fractions on Cx. quinquefasciatus larvae. The highest mortality percent of the pupae were also recorded with N-hexane and chloroform fractions on An. gambiae at 2500 ppm. As for Cx. quinquefasciatus only 50 % and 36 % mortality were recorded with N-hexane and chloroform fractions respectively.Conclusion: The extract of A. senegalensis was toxic on immature stage of mosquito species tested. By splitting methanolic crude extract, only N-hexane and chloroform fractions were revealed to possess a mosquitocidal effects and could be considered and utilized for future immature mosquito vectors control.

Efficacy of diflubenzuron, a chitin synthesis inhibitor, against Culex pipiens larvae in septic tank water.

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

2006-06-01

The mosquito Culex pipiens L. is an important pest in urban and suburban areas in many parts of the world. Septic tanks are the most important habitats supporting the production of this species in the city of Antalya, southwestern Turkey. Diflubenzuron, in a 25% wettable powder (Du-dim 25 WP), and a 4% granular formulation (Du-dim 4 G) was evaluated against late 2nd to early 3rd instars of Cx. pipiens in single-family septic tanks. Both formulations were tested at 0.01, 0.02, and 0.03 mg (AI)/liter. The results indicated that both formulations applied at the rate of 0.02 and 0.03 mg (AI)/liter achieved 100% adult inhibition, at intervals of 7, 14, 21, and 28 days after treatment. Septic tanks treated with 0.01 mg (AI)/liter WP formulation resulted in complete (100%) adult inhibition through 14 days, whereas the G formulation gave the same effect through 21 days posttreatment at this rate.

Expresión de la toxina Cry11Aa de Bacillus thuringiensis serovar. israelensis en Asticcacaulis excentricus, para el control de larvas acuáticas de dípteros de la familia Culicidae, vectores de enfermedades Expression of Bacillus thuringiensis serovar. israelensis toxins in Asticcacaulis excentricus to control dipteran larvae of vectors of diseases

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Orduz Sergio

2004-07-01

Full Text Available Los genes cry de Bacillus thuringiensis codifican para un diverso grupo de proteínas formadoras de cristales que exhiben actividad insecticida contra larvas de dípteros, lepidópteros y coleópteros, entre otros. La efectividad de los insecticidas basados en formulaciones de proteínas de B. thuringiensis puede ser mejorada usando bacterias prostecadas acuáticas como portadoras alternativas de los genes cry, ya que no se sedimentan rápidamente; las proteínas expresadas en el citoplasma están protegidas de los rayos ultra violeta y, lo más importante, las larvas de los mosquitos se alimentan de ellas. Una cepa de referencia de Asticcacaulis excentricus fue transformada con el plásmido pSOD3, el cual contiene el gen que codifica para la proteína Cry1 1 Aa de B. thuringiensis serovar. israelensis. La expresión de la proteína recombinante fue evaluada por electroforesis de proteínas y por Western blot. El Western blot revelado con un anticuerpo policlonal anti-Cry1 1 Aa mostró una banda de 72 kDa correspondiente a la proteína Cry 11 Aa. La toxicidad de las cepas de A. excentricus transformadas fue evaluada en bioensayos con larvas de primer estadío del mosquito Culex quinquefasciatus. Se alcanzó un promedio de mortalidad del 50% de las larvas de primer instar a concentraciones de 23 ng/mL de la toxina. Otros bioensayos indican que A. excentricus recombinante es tóxica para larvas de primer instar de las especies Aedes aegypti y Anopheles albimanus. Los ensayos de flotabilidad indican que A. excentricus no sedimenta hasta pasados 7 días, mientras que B. thuringiensis serovar. israelensis sedimenta al cabo de algunas horas. Palabras clave: Asticcacaulis excentricus, Bacillus thuringiensis, bacterias prostecadas, dengue, malaria.Bacillus thuringiensis cry genes encode for a diverse group of crystal-forming proteins that exhibit insecticidal activity towards dipteran, lepidopteran and coleopteran larvae. The effectiveness of

Susceptibility Of Mosquito Larvae To Conventional Insecticides In A ...

African Journals Online (AJOL)

... 0.48, 37.09 and 0.29 μg per liter respectvely. The LD50 values for Culex quinquefasciatus of exposed to dieldrin, dichlovos and cypermethrin were 0.11 10.05 and 005 μg per liter respectively. Keywords: Aedes aegypti, Culex quinquefasciatus, LC50, Dieldrin, Dichlovos, Cypermethrin. Animal Research International Vol.

Forty years of erratic insecticide resistance evolution in the mosquito Culex pipiens.

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Pierrick Labbé

2007-11-01

Full Text Available One view of adaptation is that it proceeds by the slow and steady accumulation of beneficial mutations with small effects. It is difficult to test this model, since in most cases the genetic basis of adaptation can only be studied a posteriori with traits that have evolved for a long period of time through an unknown sequence of steps. In this paper, we show how ace-1, a gene involved in resistance to organophosphorous insecticide in the mosquito Culex pipiens, has evolved during 40 years of an insecticide control program. Initially, a major resistance allele with strong deleterious side effects spread through the population. Later, a duplication combining a susceptible and a resistance ace-1 allele began to spread but did not replace the original resistance allele, as it is sublethal when homozygous. Last, a second duplication, (also sublethal when homozygous began to spread because heterozygotes for the two duplications do not exhibit deleterious pleiotropic effects. Double overdominance now maintains these four alleles across treated and nontreated areas. Thus, ace-1 evolution does not proceed via the steady accumulation of beneficial mutations. Instead, resistance evolution has been an erratic combination of mutation, positive selection, and the rearrangement of existing variation leading to complex genetic architecture.

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.

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

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1972-01-01

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

Baseline Susceptibility of Filarial Vector Culex quinquefasciatus (Diptera: Cu-licidae to Five Insecticides with Different Modes of Action in Southeast of Iran

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Yaser Salim-Abadi

2017-12-01

Full Text Available Background: Culex quinquefasciatus (Diptera: Culicidae is an important vector for many human diseases. The aim of this study was to evaluate the susceptibility level of larval and adult stages of Cu. quinquefasciatus to different groups of WHO recommended insecticides for vector control.Methods: Larval stages of the Culex mosquitoes were collected from their natural habitats in Rafsanjan County at Kerman Province, southeast of Iran in 2016. Insecticide susceptibility status of adult female Cx. quinquefasciatus against DDT (4%, deltamethrin (0.05%, malathion 5%, and bendiocarb (0.1% were determined using WHO stand­ard insecticide susceptibility test. Additional test was carried out to determine the susceptibility status of larvae of Cx. quinquefasciatus to temephos. Bioassay data were analyzed by Probit program.Results: Cx. quinquefasciatus adults showed resistance to all four groups of the tested insecticides according to the WHO criteria for resistance evaluation. The lethal concentrations for 50% mortality (LC50 and 90% mortality (LC90 of temephos against Cx. quinquefasciatus larvae were 0.18mg/l and 0.78mg/l, respectively. This finding also con­firms resistance to temephos based on the WHO recommended instructions for resistance evaluation.Conclusion: Resistance to all groups of the tested insecticides should be considered for future vector control investi­gations in the study area.

Eco-virological survey of Aedes mosquito larvae in selected dengue outbreak areas in Malaysia.

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Rohani, A; Aidil Azahary, A R; Malinda, M; Zurainee, M N; Rozilawati, H; Wan Najdah, W M A; Lee, H L

2014-12-01

BACKGROUND & OBJECTIVESI: Transovarial transmission of dengue virus in the Aedes vectors is now a well-documented phenomenon reported from many parts of the endemic areas in the world, which played an important role in initiating and maintaining the outbreak in human populations. This study investigated the factors affecting breeding habitats and the relationship with transovarial dengue virus in larvae of Aedes aegypti and Ae. albopictus. Larval surveillance was conducted in dengue outbreak areas in Malaysia from 2008 until 2009. Sampling was carried out based on habitat type, water condition (substrate type), canopy coverage, temperature and pH at breeding habitats. RT-PCR was performed to detect presence of transovarial dengue virus in larvae collected in the study areas. A total of 789 breeding habitats were identified during this study and the majority of these breeding sites were plastic containers (57.46%). Aedes albopictus dominated most of the water condition surveyed, while Ae. aegypti indicated preference toward habitats with clear water. Aedes aegypti was selective in selecting ovipositional sites compared to Ae. albopictus where shaded areas were shown to be the most preferred. From a total of 363 mosquito larvae pools, 23 (6.3%) pools were positive for dengue virus where 18 of them were from Ae. albopictus and five were from Ae. aegypti mosquito larvae pools. This study indicated the presence of transovarial transmission of dengue virus in immature Ae. aegypti and Ae. albopictus in the field. This study also showed that combination of water conditions, canopy coverage, temperature and pH of breeding habitats were the factors affecting the larval population. The study suggested that larval survey programme could serve as a tool not only to monitor the local dengue vector distribution but also to provide objective information for taking appropriate action by the community against dengue vectors.

Laboratory evaluation of methanolic extract of Atlantia monophylla (Family: Rutaceae against immature stages of mosquitoes and non-target organisms

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N Sivagnaname

2004-02-01

Full Text Available Methanolic extracts of the leaves of Atlantia monophylla (Rutaceae were evaluated for mosquitocidal activity against immature stages of three mosquito species, Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti in the laboratory.Larvae of Cx. quinquefasciatus and pupae of An. stephensi were found more susceptible, with LC50 values of 0.14 mg/l and 0.05 mg/l, respectively. Insect growth regulating activity of this extract was more pronounced against Ae. aegypti, with EI50 value 0.002 mg/l. The extract was found safe to aquatic mosquito predators Gambusia affinis, Poecilia reticulata, and Diplonychus indicus, with the respective LC50 values of 23.4, 21.3, and 5.7 mg/l. The results indicate that the mosquitocidal effects of the extract of this plant were comparable to neem extract and certain synthetic chemical larvicides like fenthion, methoprene, etc.

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

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Howard Annabel FV

2010-09-01

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

Review: artificial container-breeding mosquitoes and cemeteries: a perfect match.

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Vezzani, Darío

2007-02-01

Artificial container-breeding mosquitoes, such as Aedes aegypti, Ae. albopictus, and Culex pipiens, are well-recognized vectors of diseases throughout the world. Cemeteries are considered major sources of mosquitoes and the results of more than 30 studies concerning mosquitoes in cemeteries have been published over the last decade. The characteristics of these environments in regard to the availability of resources for mosquito development were discussed. Also, studies about early detection of Aedes vectors, ecological issues, and mosquito control performed in cemeteries were reviewed. Among 31 mosquito species found breeding in cemeteries from 16 countries, the invasive Ae. aegypti and Ae. albopictus were the most frequent ones. Species of the genus Ochlerotatus, Culex, Toxorhynchites, Culiseta, Armigeres, Lutzia, Uranotaenia, and Tripteroides were also reported. Overall, cemeteries are highly suitable habitats for artificial container-breeding mosquitoes due to the great availability of the different resources that they need (i.e. sugar substances, blood, shelter and water-filled containers). In addition, these places are mostly ideal settings to perform studies in urbanized areas because of high mosquito abundance, heterogeneity of macro- and microhabitats, and an easier access in comparison with private premises. However, the feasibility of a cemetery as a study area must be evaluated in each case considering the objectives of the study and cemetery characteristics.

Analysis of Culex and Aedes mosquitoes in southwestern Nigeria ...

African Journals Online (AJOL)

Introduction: Amplification and transmission of West Nile virus (WNV) by mosquitoes are driven by presence and number of viraemic/susceptible avian hosts. Methods: in order to predict risk of WNV infection to humans, we collected mosquitoes from horse stables in Lagos and Ibadan, southwestern Nigeria. The mosquitoes ...

Host-feeding patterns of native Culex pipiens and invasive Aedes albopictus mosquitoes (Diptera: Culicidae) in urban zones from Barcelona, Spain.

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Muñnoz, Joaquin; Eritja, Roger; Alcaide, Miguel; Montalvo, Tomás; Soriguer, Ramón C; Figuerola, Jordi

2011-07-01

The feeding patterns of haematophagous arthropods are of major importance in the amplification and transmission of infectious disease agents to vertebrate hosts, including humans. The establishment of new vector populations in nonnative range might alter transmission networks. The Asian tiger mosquito Aedes albopictus (Skuse) represents an example of how an invasive species can alter the risk of viral transmission to humans. Blood meal molecular identification from two sympatric mosquito species (the invasive Ae. albopictus and the native Culex pipiens) was carried out by polymerase chain reaction-based methods. Samples were collected in Barcelona metropolitan area, Spain, from June to October 2009 as part of a monitoring-control program. Blood meals were identified to the species level in 30 Ae. albopictus and 43 Cx. pipiens. Ae. albopictus acquired blood exclusively from human hosts (100%), whereas Cx. pipiens fed on a diversity of avian and mammalian hosts, including 35.7% of blood meals from humans. Based on mosquito diet, our results suggest that the Ae. albopictus invasion in Spain might increase the risk of virus transmission to humans and could support local outbreaks of imported tropical viruses such as dengue and chikungunya. However, in the studied area, the presence of this invasive species would have a negligible effect on the transmission of zoonotic agents such as West Nile virus. However, Cx. pipiens could amplify and transmit West Nile virus, but avian contribution to its diet was lower than that reported in North America. Feeding patterns of these mosquito species may help to understand the flavivirus outbreaks recently reported in southwestern Europe.

Comparative Analysis of Major Mosquito Vectors Response to Seed-Derived Essential Oil and Seed Pod-Derived Extract from Acacia nilotica

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Perumal Vivekanandhan

2018-02-01

Full Text Available Botanical metabolites are increasingly realized as potential replacements to chemical insecticides. In the present study, Acacia nilotica seed essential oil and seed pod solvent extracts were tested for bioefficacy against three important types of mosquitoes. Mortality was recorded 24 h post-treatment, while smoke toxicity of adult mosquitoes was recorded at 10 min intervals for 40 min. Seed pod powder was extracted with different solvents and hydrodistilled seed oil chemical constituents were determined by using Gas chromatography mass spectroscopy (GC-MS -. Larvicidal and adulticidal efficacy of seed hydrodistilled essential oil and solvent extracts were tested against larval and adult mosquitoes. The seed hydrodistilled oil provided strong larvicidal activity against Anopheles stephensi, (LC50 (lethal concentration that kills 50% of the exposed larvae = 5.239, LC90 (lethal concentration that kills 90% of the exposed larvae = 9.713 mg/L; Aedes aegypti, (LC50 = 3.174, LC90 = 11.739 mg/L; and Culex quinquefasciatus, (LC50 = 4.112, LC90 = 12.325 mg/L. Smoke toxicities were 82% in Cx. quinquefasciatus, 90% in Ae. aegypti, and 80% mortality in An. stephensi adults, whereas 100% mortality was recorded for commercial mosquito coil. The GC-MS profile of seed essential oil from A. nilotica showed the presence of hexadecane (18.440% and heptacosane (15.914%, which are the main and active compounds, and which may be involved in insecticidal activity. Overall findings suggest that the seed oil showed strong mosquitocidal activity against mosquito vectors and therefore may provide an ecofriendly replacement to chemical insecticides.

Larvicidal, ovicidal, and oviposition-deterrent activities of four plant extracts against three mosquito species.

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Prathibha, K P; Raghavendra, B S; Vijayan, V A

2014-05-01

In mosquito control programs, insecticides of botanical origin have the potential to eliminate eggs, larvae, and adults. So, the larvicidal, ovicidal, and oviposition-deterrent activities of petroleum ether and ethyl acetate extracts of the leaves of Eugenia jambolana, Solidago canadensis, Euodia ridleyi, and Spilanthes mauritiana were assayed against the three vector mosquito species, namely Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. The larval bioassay was conducted following the World Health Organization method. The maximum larval mortality was found with ethyl acetate extract of S. mauritiana against the larvae of A. stephensi, A. aegypti, and C. quinquefasciatus with LC50 values of 11.51, 28.1, 14.10 ppm, respectively. The mean percent hatchability of the ovicidal activity was observed at 48-h post-treatment. The percent hatchability was found to be inversely proportional to the concentration of the extract and directly proportional to the number of eggs. The flower head extract of S. mauritiana gave 100% mortality followed by E. ridleyi, S. canadensis, and E. jambolana against the eggs of the three mosquito vectors. For oviposition-deterrent effect, out of the five concentrations tested (20, 40, 60, 80, and 100 ppm), the concentration of 100 ppm showed a significant egg laying-deterrent capacity. The oviposition activity index value of E. jambolana, E. ridleyi, S. canadensis, and S. mauritiana against A. aegypti, A. stephensi, C. quinquefasciatus at 100 ppm were -0.71, -0.71, -0.90, -0.93, -0.85, -0.91, -1, -1, -0.71, -0.85, -1, and -1, respectively. These results suggest that the leaf/flower extracts of certain local plants have the potential to be developed as possible eco-friendly means for the control of mosquitoes.

Discovery of Novel Viruses in Mosquitoes from the Zambezi Valley of Mozambique.

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Harindranath Cholleti

Full Text Available Mosquitoes carry a wide variety of viruses that can cause vector-borne infectious diseases and affect both human and veterinary public health. Although Mozambique can be considered a hot spot for emerging infectious diseases due to factors such as a rich vector population and a close vector/human/wildlife interface, the viral flora in mosquitoes have not previously been investigated. In this study, viral metagenomics was employed to analyze the viral communities in Culex and Mansonia mosquitoes in the Zambezia province of Mozambique. Among the 1.7 and 2.6 million sequences produced from the Culex and Mansonia samples, respectively, 3269 and 983 reads were classified as viral sequences. Viruses belonging to the Flaviviridae, Rhabdoviridae and Iflaviridae families were detected, and different unclassified single- and double-stranded RNA viruses were also identified. A near complete genome of a flavivirus, tentatively named Cuacua virus, was obtained from the Mansonia mosquitoes. Phylogenetic analysis of this flavivirus, using the NS5 amino acid sequence, showed that it grouped with 'insect-specific' viruses and was most closely related to Nakiwogo virus previously identified in Uganda. Both mosquito genera had viral sequences related to Rhabdoviruses, and these were most closely related to Culex tritaeniorhynchus rhabdovirus (CTRV. The results from this study suggest that several viruses specific for insects belonging to, for example, the Flaviviridae and Rhabdoviridae families, as well as a number of unclassified RNA viruses, are present in mosquitoes in Mozambique.

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.

Culex quinquefasciatus (Diptera: Culicidae From Florida Transmitted Zika Virus

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Chelsea T. Smartt

2018-04-01

Full Text Available We report a laboratory colony of Culex quinquefasciatus mosquitoes were experimentally able to salivate Zika virus (ZIKV, Flaviviridae; Flavivirus at 16 days post infection (dpi. ZIKV RNA was detected in bodies and in saliva deposited on filter paper cards with subsequent studies demonstrating the presence of live ZIKV in saliva.

An overview of mosquitoes and emerging arboviral infections in the Zagreb area, Croatia.

Science.gov (United States)

Klobucar, Ana; Benic, Nikola; Krajcar, Darko; Kosanovic-Licina, Mirjana Lana; Tesic, Vanja; Merdic, Enrih; Vrucina, Ivana; Savic, Vladimir; Barbic, Ljubo; Stevanovic, Vladimir; Pem-Novosel, Iva; Vilibic-Cavlek, Tatjana

2016-12-30

Mosquito control in the Zagreb area has been conducted for many years, whereas the fauna has only been investigated in the last 20 years. So far 30 mosquito species have been detected in the city area. Culex pipiens form molestus is the dominant mosquito species in indoor breeding sites. In forested areas and areas exposed to flooding, the active period is early spring and the dominant species are Ochlerotatus sticticus, Ochlerotatus cantans, Ochlerotatus geniculatus and Aedes vexans. The eudominant mosquito species found in the artificial breeding sites are Culex pipiens and the Asian tiger mosquito, Aedes albopictus. Invasive Ae. albopictus, present in the Zagreb area since 2004, has expanded to a larger area of the city during the last three years. The recent emergence of the human West Nile virus and Usutu virus neuroinvasive disease in Zagreb and its surroundings highlighted the role of mosquitoes as vectors of emerging arboviruses. The paper focuses on mosquito species and arboviral infections detected in humans and animals in the Zagreb area, Croatia.

Adulticidal activity of Pithecellobium dulce (Roxb.) Benth. against Culex quinquefasciatus (Say)

OpenAIRE

Govindarajan M; Sivakumar R; Rajeswary M; Yogalakshmi K

2012-01-01

Objective: To determine the adulticidal efficacy of different solvent leaf and seed extracts of Pithecellobium dulce (P. dulce) against Culex quinquefasciatus (Cx. quinquefasciatus). Methods: Sucrose-fed and blood starved mosquitoes were released into the tube, and the mortality effects of the extracts were observed every 10 min for 3 h exposure period. At the end of 1, 2, and 3 h exposure periods, the mosquitoes were placed in the holding tube. Cotton pads soaked in 10% sugar ...

Application for the post of Lecturer in Zoology for FDP Vacancy

African Journals Online (AJOL)

om

2013-11-13

Nov 13, 2013 ... Preliminary screening of plant essential oils against larvae of Culex ... parts of India especially in Kerala, Mysore, Tamil Nadu, ... phytochemicals which are widely used as alternatives to synthetic ... oils against mosquitoes as growth inhibitors and/or ... toxicity and mosquito repellency of Ocimum selloi oil.

Bioactivity of sea grass against the malarial fever mosquito Culex quinquefasciatus

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Suburamaniyan Vijayakumar

2014-08-01

Full Text Available Objective: To identify the larvicidal activity of the seagrass extracts against Culex quinquefasciatus (Cx. quinquefasciatus Methods: Seagrass extracts, Halodule pinifolia (H. pinifolia, Cymodocea serrulata (C. serrulata and Thalasia testudinum (T. testudinum were dissolved in dimethylsulfoxide to prepare a graded series of concentration. Batches of 25 early 4th instars larvae of Cx. quinquefasciatus were transferred to 250 mL enamel bowl containing 199 mL of distilled water and 1 mL of plant extracts (0.01 mg-0.1 mg. After 24 h the mortality rate was identified with the formulae [(% of test mortality - % of control mortality/(100 - % of control mortality]伊100. Each experiment was conducted with three replicates and a concurrent control group. A control group consisted of 1 mL of dimethylsulfoxide and 199 mL of distilled water only. Results: The root extract of H. pinifolia showed maximum larvicidal activity with minimum concentration of extract of LC 50 value of (0.614依0.006 µg/mL with lower confidence limit-upper confidence limit value of (0.052-0.072 and LC90 value of 0.9120 µg/mL followed by leaf extract of C. serrulata LC 50 value of (0.074依0.008 µg/mL and LC90 value of 0.1487 µg/mL. T. testudinum leaf extract showed LC 50 value of (0.082依0.006 µg/mL. The regression equation of root and leaf extract of H. pinifolia for 4 th instar larvae of Cx. quinquefasciatus were Y=5.229+1.36x (R2=0.993 and Y=2.369+1.21x (R2=0.878 respectively and analysis of variation was significant at P<0.05 level. The result of the preliminary phytochemical constituents showed the presence of saponin, steroids, terpenoid, phenols, protein and sugars. Conclusions: From the present study the ethanolic extracts of seagrass of H. pinifolia possess lead compound for development of larvicidal activity.

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

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Paradise Christopher J

2001-08-01

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

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

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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.

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

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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

Efficacy of agnique (mmf) monomolecular surface film against immature stages of Anopheles arabiensis patton and Culex spp (diptera: culicidae) in Khartoum, Sudan.

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Bashir, Al; Hassan, A Abu; Salmah, M R Che; Rahman, W A

2008-03-01

The efficacy of the larvicidal and pupicidal agent (Agnique) MMF was evaluated against larvae of An. arabiensis and Culex (Diptera: Culicidae) under field conditions in Bahary Locality, Khartoum, Sudan. At an applied dosage of 0.25 ml/m2, MMF resulted in 89.4, 79.8 and 88.2% reductions in L3-L4 instars An. arabiensis and 63.5% in Culex larvae (all stages) 24 to 72 hours post-treatment. Pupae were completely eliminated (100%) within 24 hours posttreatment. The earlier instars (L1-L2) of An. arabiensis were more tolerant with a 62.5% reduction at 72 hours post-treatment compared to (L3-L4) instars and pupae. At 7-days post-treatment Agnique gave a 57.5% reduction in L1-L2 and 92.6% in L3-L4 instar larvae of An. arabiensis and 57.3% and 86.4% in Culex larvae and pupae, respectively. We conclude that Agnique can perform effectively against L3-L4 instars and pupae of An. arabiensis for only 1 week, and 3 to 4 days against L1-L2 instars of Culex spp.

Larvicidal efficacies and chemical composition of essential oils of Pinus sylvestris and Syzygium aromaticum against mosquitoes.

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Fayemiwo, Kehinde Adenike; Adeleke, Monsuru Adebayo; Okoro, Ovie Princewill; Awojide, Shola Hezekiah; Awoniyi, Ilias Olufemi

2014-01-01

To assess the chemical composition and mosquito larvicidal potentials of essential oils of locally sourced Pinus sylvestris (P. sylvestris) and Syzygium aromaticum (S. aromaticum) against Aedes aegypti (A. aegypti) and Culex quinquefasciatus (C. quinquefasciatus). The chemical composition of the essential oils of both plants was determined using GC-MS while the larvicidal bioassay was carried out using different concentrations of the oils against the larvae of A. aegypti and C. quinquefasciatus in accordance with the standard protocol. The results as determined by GC-MS showed that oil of S. aromaticum has eugenol (80.5%) as its principal constituent while P. sylvestris has 3-Cyclohexene-1-methanol, .alpha., .alpha.4-trimethyl (27.1%) as its dominant constituent. Both oils achieved over 85% larval mortality within 24 h. The larvae of A. aegypti were more susceptible to the oils [LC50 (S. aromaticum)=92.56 mg/L, LC50(P. sylvestris)=100.39 mg/L] than C. quinquefasciatus [LC50(S. aromaticum)=124.42 mg/L; LC50(P. sylvestris)=128.00 mg/L]. S. aromaticum oil was more toxic to the mosquito larvae than oil of P. sylvestris but the difference in lethal concentrations was insignificant (P>0.05). The results justify the larvicidal potentials of both essential oils and the need to incorporate them in vector management and control. Copyright © 2014 Asian Pacific Tropical Biomedical Magazine. Published by Elsevier B.V. All rights reserved.

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

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Mariana Rocha David

2012-10-01

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

Larvicidal activity of Nerium oleander L. (Apocynaceae flower extracts against Culex quinquefasciatus Say (Diptera: Culicidae

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R. Raveen

2014-03-01

Full Text Available Culex quinquefasciatus is the vector responsible for serious disease filariasis among human beings. Plant derived products have received increased attention from scientists as they serve as a rich source for novel natural substances possessing insecticidal properties which are safe to human and ecosystem. During the last decade, various studies on natural plant products against vector mosquito indicate them as possible alternatives to chemical and synthetic insecticides for mosquito control. In the present study, the crude hexane and aqueous extract of Nerium oleander flowers were reported for larvicidal activity against the filarial vector, Culex quinquefasciatus. Mortality was observed for 24 and 48 hours. Hexane flower extract exhibited highest larvicidal activity with a LC50 value of 102.54 ppm and 61.11ppm after 24 and 48 hours respectively. Further investigations are needed to elucidate this activity against a wide range of all stages of mosquito species and also the active ingredient(s of the extract responsible for larvicidal activity should be identified.

Mosquito fauna of a tropical museum and zoological garden complex

African Journals Online (AJOL)

The mosquito fauna of Museum and Zoological Garden Complex (JZC), a major tourist attraction inJos Metropolis of Nigeria, was studied The choice of the complex was out of public health curiosity. A total of 627 mosquitoes comprising 4 genera, Aedes, Culex, Coquilletidia and Eretmapodites, and9 species were caught n ...

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

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Kumar, K Ramesh; Nattuthurai, N; Gopinath, Ponraj; Mariappan, Tirupathi

2015-02-01

Mosquitoes are the major vector for the transmission of malaria, dengue fever, yellow fever, filariasis, chikungunya and Japanese encephalitis, and they accounted for global mortality and morbidity with increased resistance to common insecticides. The aim of this study was to investigate the larvicidal potential of the acetone leaf extracts of Morinda tinctoria and synthesized silver nanoparticles against third instar larvae of Culex quinquefasciatus Say (Diptera: Culicidae). Nanoparticles are being used in many commercial applications. It was found that aqueous silver ions can be reduced by aqueous extract of plant parts to generate extremely stable silver nanoparticles in water. Synthesized AgNPs were characterized by ultraviolet-visible (UV-vis) spectroscopy, Atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FT-IR) analysis. The synthesized silver nanoparticles have also been tested against the third instar larvae of C. quinquefasciatus. The leaf extract and the AgNPs high mortality values were 50 % lethal concentration (LC50) = 8.088 and 1.442 ppm against C. quinquefasciatus, respectively. The results recorded from ultraviolet-visible spectroscopy, atomic force microscopy and Fourier transform infrared spectroscopy support the biosynthesis and characterization of silver nanoparticles. These results suggest that the leaf extract of M. tinctoria and synthesis of AgNPs have the potential to be used as an ideal eco-friendly approach for the control of C. quinquefasciatus. By this approach, it is suggestive that this rapid synthesis of nanoparticles would be proper for developing a biological process for mosquito control.

Structure and expression strategy of the genome of Culex pipiens densovirus, a mosquito densovirus with an ambisense organization.

Science.gov (United States)

Baquerizo-Audiot, Elizabeth; Abd-Alla, Adly; Jousset, Françoise-Xavière; Cousserans, François; Tijssen, Peter; Bergoin, Max

2009-07-01

The genome of all densoviruses (DNVs) so far isolated from mosquitoes or mosquito cell lines consists of a 4-kb single-stranded DNA molecule with a monosense organization (genus Brevidensovirus, subfamily Densovirinae). We previously reported the isolation of a Culex pipiens DNV (CpDNV) that differs significantly from brevidensoviruses by (i) having a approximately 6-kb genome, (ii) lacking sequence homology, and (iii) lacking antigenic cross-reactivity with Brevidensovirus capsid polypeptides. We report here the sequence organization and transcription map of this virus. The cloned genome of CpDNV is 5,759 nucleotides (nt) long, and it possesses an inverted terminal repeat (ITR) of 285 nt and an ambisense organization of its genes. The nonstructural (NS) proteins NS-1, NS-2, and NS-3 are located in the 5' half of one strand and are organized into five open reading frames (ORFs) due to the split of both NS-1 and NS-2 into two ORFs. The ORF encoding capsid polypeptides is located in the 5' half of the complementary strand. The expression of NS proteins is controlled by two promoters, P7 and P17, driving the transcription of a 2.4-kb mRNA encoding NS-3 and of a 1.8-kb mRNA encoding NS-1 and NS-2, respectively. The two NS mRNAs species are spliced off a 53-nt sequence. Capsid proteins are translated from an unspliced 2.3-kb mRNA driven by the P88 promoter. CpDNV thus appears as a new type of mosquito DNV, and based on the overall organization and expression modalities of its genome, it may represent the prototype of a new genus of DNV.

Mosquito blood-meal analysis for avian malaria study in wild bird communities: laboratory verification and application to Culex sasai (Diptera: Culicidae) collected in Tokyo, Japan.

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Kim, Kyeong Soon; Tsuda, Yoshio; Sasaki, Toshinori; Kobayashi, Mutsuo; Hirota, Yoshikazu

2009-10-01

We conducted laboratory experiments to verify molecular techniques of avian malaria parasite detection distinguishing between an infected mosquito (oocysts on midgut wall) and infective mosquito (sporozoites in salivary glands) in parallel with blood-meal identification from individual blood-fed mosquitoes prior to application to field survey for avian malaria. Domestic fowl infected with Plasmodium gallinaceum was exposed to a vector and non-vector mosquito species, Aedes aegypti and Culex pipiens pallens, respectively, to compare the time course of polymerase chain reaction (PCR) detection for parasite between competent and refractory mosquitoes. DNA of the domestic fowl was detectable for at least 3 days after blood feeding. The PCR-based detection of P. gallinaceum from the abdomen and thorax of A. aegypti corresponded to the microscopic observation of oocysts and sporozoites. Therefore, this PCR-based method was considered useful as one of the criteria to assess developmental stages of Plasmodium spp. in mosquito species collected in the field. We applied the same PCR-based method to 21 blood-fed C. sasai mosquitoes collected in Rinshi-no-mori Park in urban Tokyo, Japan. Of 15 blood meals of C. sasai successfully identified, 86.7% were avian-derived, 13.3% were bovine-derived. Plasmodium DNA was amplified from the abdomen of three C. sasai specimens having an avian blood meal from the Great Tit (Parus major), Pale Thrush (Turdus pallidus), and Jungle Crow (Corvus macrorhynchos). This is the first field study on host-feeding habits of C. sasai in relation to the potential role as a vector for avian malaria parasites transmitted in the Japanese wild bird community.

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

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Hasan Boesri

2013-02-01

Full Text Available Abstracts. The evaluation of piretroid insecticide (active ingredient Malation 95% was con­ducted in Sub district Tengarang, Semarang Segency, Central Java Province. The insecti­cide 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 fil­ariasis 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.Key Word: Aedes aegypti, Culex quinquefasciatus, insecticide Piretroid (Malation 95%, thermal fogging.

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

EPA-Registered Repellents for Mosquitoes Transmitting Emerging Viral Disease.

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

2016-12-01

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

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

Science.gov (United States)

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

2012-08-01

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

Species Composition and Ecological Aspects of Immature Mosquitoes (Diptera: Culicidae in Bromeliads in Urban Parks in the City of São Paulo, Brazil

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Walter Ceretti-Junior

2015-10-01

Full Text Available Background: Bromeliads can be epiphytic, terrestrial or saxicolous and use strategies to allow water to be re­tained in their leaf axils, where various arthropods can be found. These include mosquitoes, whose larvae are the most abundant and commonly found organisms in the leaf axils. The objective of this study was to look for im­mature forms of mosquitoes (the larval and pupal stages in bromeliads in municipal parks in São Paulo and to discuss the ecological and epidemiological importance of these insects.Methods: From October 2010 to July 2013, immature mosquitoes were collected from bromeliads in 65 munici­pal parks in the city of São Paulo, Brazil, using suction samplers. The immature forms were maintained until adult forms emerged, and these were then identified morphologically.Results: Two thousand forty-two immature-stage specimens belonging to the genera Aedes, Culex, Trichoprosopon, Toxorhynchites, Limatus and Wyeomyia were found in bromeliads in 15 of the 65 parks visited. Aedes albopictus was the most abundant species (660 specimens collected, followed by Culex quinquefasciatus (548 specimens and Cx. (Microculex imitator (444. The taxa with the most widespread distribution were Ae. aegypti and Toxorhynchites spp, followed by Ae. albopictus and Cx. quinquefasciatus.Conclusion: Bromeliads in urban parks are refuges for populations of native species of Culicidae and breeding sites for exotic species that are generally of epidemiological interest. Hence, administrators and surveillance and mosquito-control agencies must constantly monitor these microenvironments as the presence of these species endangers the health of park users and employees as well as people living near the parks. 

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.

Mosquito control pesticides and sea surface temperatures have differential effects on the survival and oxidative stress response of coral larvae.

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Ross, Cliff; Olsen, Kevin; Henry, Michael; Pierce, Richard

2015-04-01

The declining health of coral reefs is intensifying worldwide at an alarming rate due to the combined effects of land-based sources of pollution and climate change. Despite the persistent use of mosquito control pesticides in populated coastal areas, studies examining the survival and physiological impacts of early life-history stages of non-targeted marine organisms are limited. In order to better understand the combined effects of mosquito pesticides and rising sea surface temperatures, we exposed larvae from the coral Porites astreoides to selected concentrations of two major mosquito pesticide ingredients, naled and permethrin, and seawater elevated +3.5 °C. Following 18-20 h of exposure, larvae exposed to naled concentrations of 2.96 µg L(-1) or greater had significantly reduced survivorship compared to controls. These effects were not detected in the presence of permethrin or elevated temperature. Furthermore, larval settlement, post-settlement survival and zooxanthellae density were not impacted by any treatment. To evaluate the sub-lethal stress response of larvae, several oxidative stress endpoints were utilized. Biomarker responses to pesticide exposure were variable and contingent upon pesticide type as well as the specific biomarker being employed. In some cases, such as with protein carbonylation and catalase gene expression, the effects of naled exposure and temperature were interactive. In other cases pesticide exposure failed to induce any sub-lethal stress response. Overall, these results demonstrate that P. astreoides larvae have a moderate degree of resistance against short-term exposure to ecologically relevant concentrations of pesticides even in the presence of elevated temperature. In addition, this work highlights the importance of considering the complexity and differential responses encountered when examining the impacts of combined stressors that occur on varying spatial scales.

Immobilization of alginate-encapsulated Bacillus thuringiensis var. israelensis containing different multivalent counterions for mosquito control.

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Prabakaran, G; Hoti, S L

2008-08-01

Immobilized techniques have been used widely for the controlled release formulation of mosquitoes. Among the microbial formulations, polymeric matrices play an important role in the controlled release of microbial pesticide at rates sufficiently effective to kill mosquitoes in the field. The advantage of these matrices is that they enhance the stability of both spores and toxin against pH, temperature variations, and UV irradiation. The disadvantage of using calcium alginate beads is that they are unstable upon contact with phosphate of potassium or sodium ions rich in the mosquito habitats. To overcome these problems, attempts were made to encapsulate Bacillus thuringiensis var. israelensis within alginate by using different multivalent counterions, namely, calcium chloride, zinc sulfate, copper sulfate, cobalt chloride, and ferric chloride, and the beads formed were tested for its mosquito larvicidal activity. Among all the beads tested, zinc alginate beads resulted in maximum larvicidal activity of 98% (+/-1.40 SE) against Culex quinquefasciatus IIIrd instar larvae and maximum spore count of 3.36 x 10(5) (+/-5291.50 SE) CFU/ml. Zinc alginate beads maintained their structure for up to 48 h when shaken vigorously on a rotary shaker at 180 rpm in the presence of 10 mM potassium phosphate buffer (pH 6.8 +/- 0.1). In conclusion, our results suggest that the use of zinc sulfate as counterions to encapsulate B. thuringiensis var. israelensis within alginate may be a potent mosquito control program in the habitats where more phosphate ions are present.

Ocular Manifestations of Mosquito-Transmitted Diseases.

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Karesh, James W; Mazzoli, Robert A; Heintz, Shannon K

2018-03-01

Of the 3,548 known mosquito species, about 100 transmit human diseases. Mosquitoes are distributed globally throughout tropical and temperate regions where standing water sources are available for egg laying and the maturation of larva. Female mosquitoes require blood meals for egg production. This is the main pathway for disease transmission. Mosquitoes carry several pathogenic organisms responsible for significant ocular pathology and vision loss including West Nile, Rift Valley, chikungunya, dengue viruses, various encephalitis viruses, malarial parasites, Francisella tularensis, microfilarial parasites, including Dirofilaria, Wuchereria, and Brugia spp., and human botfly larvae. Health care providers may not be familiar with many of these mosquito-transmitted diseases or their associated ocular findings delaying diagnosis, treatment, and recovery of visual function. This article aims to provide an overview of the ocular manifestations associated with mosquito-transmitted diseases.

Composition and Genetic Diversity of Mosquitoes (Diptera: Culicidae) on Islands and Mainland Shores of Kenya’s Lakes Victoria and Baringo

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Ajamma, Yvonne Ukamaka; Villinger, Jandouwe; Omondi, David; Salifu, Daisy; Onchuru, Thomas Ogao; Njoroge, Laban; Muigai, Anne W. T.; Masiga, Daniel K.

2016-01-01

The Lake Baringo and Lake Victoria regions of Kenya are associated with high seroprevalence of mosquito-transmitted arboviruses. However, molecular identification of potential mosquito vector species, including morphologically identified ones, remains scarce. To estimate the diversity, abundance, and distribution of mosquito vectors on the mainland shores and adjacent inhabited islands in these regions, we collected and morphologically identified adult and immature mosquitoes and obtained the corresponding sequence variation at cytochrome c oxidase 1 (COI) and internal transcribed spacer region 2 (ITS2) gene regions. A total of 63 species (including five subspecies) were collected from both study areas, 47 of which have previously been implicated as disease vectors. Fourteen species were found only on island sites, which are rarely included in mosquito diversity surveys. We collected more mosquitoes, yet with lower species composition, at Lake Baringo (40,229 mosquitoes, 32 species) than at Lake Victoria (22,393 mosquitoes, 54 species). Phylogenetic analysis of COI gene sequences revealed Culex perexiguus and Cx. tenagius that could not be distinguished morphologically. Most Culex species clustered into a heterogeneous clade with closely related sequences, while Culex pipiens clustered into two distinct COI and ITS2 clades. These data suggest limitations in current morphological identification keys. This is the first DNA barcode report of Kenyan mosquitoes. To improve mosquito species identification, morphological identifications should be supported by their molecular data, while diversity surveys should target both adults and immatures. The diversity of native mosquito disease vectors identified in this study impacts disease transmission risks to humans and livestock. PMID:27402888

Green synthesis of silver nanoparticles and its application for mosquito control

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Naba Kumar Mondal

2014-02-01

Full Text Available Objective: To synthesize and characterize silver nanoparticles from aqueous root extract of Parthenium hysterophorus (P. hysterophorus and also to evaluate the potentiality of synthesized silver nanoparticles as larvacidal agent against Culex quinquefasciatus (Cx. quinquefasciatus. Methods: The silver nano particles were generated using root extract of P. hysterophorus. The characterization of synthesized nanoparticles was done by visual color change, UV-Vis spectrum, scanning electron micrograph, fluorescent microscope and Fourier transform infrared spectroscopy. Results: It was found that aqueous silver ions can be reduced by aqueous root extract of P. hysterophorus to generate extremely stable silver nanoparticles in aqueous medium. Larvae were exposed to varying concentrations of plant extracts, aqueous silver nitrate solution and synthesized silver nanoparticles for 0, 24 and 48 h separately. Aqueous root extract showed moderate larvicidal effects; however, the maximum efficacy (60.18% was observed with the synthesized silver nanoparticles against the larvae of Cx. quinquefasciatus. Conclusions: These results suggest that the green synthesis of silver nanoparticles have the potential to be used as an ideal eco-friently approach for the control of the Cx. quinquefasciatus. This is the first report on the mosquito larvicidal activity of the nano particle synthesized by P. hysterophorus.

GLOBE Goes GO with Mosquitoes

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Boger, R. A.; Low, R.

2016-12-01

The GLOBE Mosquito Larvae protocol and a new citizen science initiative, GLOBE Observers (GO), were both launched in Summer 2016. While the GLOBE Mosquito Larvae Protocol and associated educational materials target K-16 student inquiry and research, the GO protocol version is simplified to enable citizen scientists of all ages from all walks of life to participate. GO allows citizen scientists to collect and submit environmental data through an easy-to-use smart phone app available for both Apple and Android mobile devices. GO mosquito asks for photos of larvae mosquito genus or species, location, and type of water source (e.g., container or pond) where the larvae were found. To initiate the new mosquito GLOBE/GO opportunities, workshops have been held in Barbuda, Thailand, West Indies, US Gulf Coast, New York City, and at the GLOBE Annual Meeting in Colorado. Through these venues, the protocols have been refined and a field campaign has been initiated so that GO and GLOBE citizen scientists (K-16 students and all others) can contribute data. Quality assurance measures are taken through the online training required to participate and the validation of identification by other citizen sciences and mosquito experts. Furthermore, initial research is underway to develop optical recognition software starting with the species that carry the Zika virus (Aedes aegypti and A. albopictus). With this launch, we plan to move forward by providing opportunities throughout the world to engage people in meaningful environmental and public health data collection and to promote citizen scientists to become agents of change in their communities.

Mosquito production from four constructed treatment wetlands in peninsular Florida.

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Rey, Jorge R; O'Meara, George F; O'Connell, Sheila M; Cutwa-Francis, Michele M

2006-06-01

Several techniques were used to sample adult and immature mosquitoes in 4 constructed treatment wetlands in Florida. Adults of 19 species (7 genera) of mosquitoes were collected, and immatures of the most abundant species and of 60% of all species also were collected. Few significant differences between sites and stations in the numbers of mosquitoes collected were discovered. Culex nigripalpus Theobald was the most abundant mosquito found in adult (carbon dioxide-baited suction traps) and ovitrap collections, whereas Mansonia spp. and Uranotaenia spp. were most common in pump-dip-grab samples. The roles of rooted and floating vegetation and of water quality in determining mosquito production from these areas are discussed.

Haematophageous vector monitoring in Djibouti city from 2008 to 2009: first records of Culex pipiens ssp. torridus (IGLISCH), and Anopheles sergentii (theobald).

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Faulde, Michael K; Ahmed, Ammar A

2010-08-01

The Horn of Africa represents a region formerly known to be highly susceptible to mosquito-borne infectious diseases. In order to monitor and analyze the current presence and threat of vector mosquitoes, continuous and standardized trapping using CDC light traps without an additional CO2-generator has been carried out at six selected monitoring sites located in Djibouti City, from August 2008 until December 2009. An overall of 620 haematophageous Diptera were trapped, 603 (97.3%) were mosquitoes, 10 (1.6%) were sand flies, and 7 (1.1%) were biting midges, respectively. Genus distribution of mosquitoes revealed that 600 (99.5%) were Culex spp., 2 (0.3%) were Anopheles sergentii, and 1 (0.2%) was Aedes aegypti. Culex species were represented by Cx. quinquefasciatus (78.5%), and Cx. pipiens ssp. torridus (21.5%). The later species was first detected focally in early December 2009 showing a strongly increasing population density resulting in a maximum trap rate of 25 mosquitoes per trap night. Sand flies were all Sergentomyia antennata, and biting midges of the genus Culicoides were represented by C. nubeculosus (71.4%) and C. vexans (28.6 %). The findings included the first records for Cx. pipiens ssp. torridus and An. sergentii in Djibouti. However, none of the captured female Culex spp, the known vector for West Nile Virus, showed positive results for viral nucleic acids using WNV RT-real time PCR system. Also, females An. sergentii were Plasmodium falciparum and P. vivax circumsporozoite protein negative.

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

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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

Potential for North American mosquitoes (Diptera: Culicidae) to transmit rift valley fever virus.

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Turell, Michael J; Wilson, William C; Bennett, Kristine E

2010-09-01

To determine which arthropods should be targeted for control should Rift Valley fever virus (RVFV) be detected in North America, we evaluated Culex erraticus (Dyar and Knab), Culex erythrothorax Dyar, Culex nigripalpus Theobald, Culex pipiens L., Culex quinquefasciatus Say, Culex tarsalis Coquillett, Aedes dorsalis (Wiedemann), Aedes vexans (Meigen), Anopheles quadrimaculatus Say, and Culicoides sonorensis Wirth and Jones from the western, midwestern, and southern United States for their ability to transmit RVFV. Female mosquitoes were allowed to feed on adult hamsters inoculated with RVFV, after which engorged mosquitoes were incubated for 7-21 d at 260C, then allowed to refeed on susceptible hamsters, and tested to determine infection, dissemination, and transmission rates. Other specimens were inoculated intrathoracically, held for 7 d, and then allowed to feed on a susceptible hamster to check for a salivary gland barrier. When exposed to hamsters with viremias > or =10(8.8) plaque-forming units/ml blood, Cx. tarsalis transmitted RVFV efficiently (infection rate = 93%, dissemination rate = 56%, and estimated transmission rate = 52%). In contrast, when exposed to the same virus dose, none of the other species tested transmitted RVFV efficiently. Estimated transmission rates for Cx. erythrothorax, Cx. pipiens, Cx. erraticus, and Ae. dorsalis were 10, 8, 4, and 2%, respectively, and for the remaining species were feeding preference, longevity, and foraging behavior should be considered when determining the potential role that these species could play in RVFV transmission.

Metofluthrin: a potent new synthetic pyrethroid with high vapor activity against mosquitoes.

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Ujihara, Kazuya; Mori, Tatsuya; Iwasaki, Tomonori; Sugano, Masayo; Shono, Yoshinori; Matsuo, Noritada

2004-01-01

(1R)-trans-Norchrysanthemic acid fluorobenzyl esters are synthesized and their structure-activity relationships are discussed. These esters show outstanding insecticidal activity against mosquitoes. In particular, the 2,3,5,6-tetrafluoro-4-methoxymethylbenzyl analog (metofluthrin) exhibits the highest potency, being approximately forty times as potent as d-allethrin in a mosquito coil formulation when tested against southern house mosquitoes (Culex quinquefasciatus). Metofluthrin also exhibits a significant vapor action at room temperature.

High chlorpyrifos resistance in Culex pipiens mosquitoes: strong synergy between resistance genes

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Alout, H; Labbé, P; Berthomieu, A; Makoundou, P; Fort, P; Pasteur, N; Weill, M

2016-01-01

We investigated the genetic determinism of high chlorpyrifos resistance (HCR), a phenotype first described in 1999 in Culex pipiens mosquitoes surviving chlorpyrifos doses ⩾1 mg l−1 and more recently found in field samples from Tunisia, Israel or Indian Ocean islands. Through chlorpyrifos selection, we selected several HCR strains that displayed over 10 000-fold resistance. All strains were homozygous for resistant alleles at two main loci: the ace-1 gene, with the resistant ace-1R allele expressing the insensitive G119S acetylcholinesterase, and a resistant allele of an unknown gene (named T) linked to the sex and ace-2 genes. We constructed a strain carrying only the T-resistant allele and studied its resistance characteristics. By crossing this strain with strains harboring different alleles at the ace-1 locus, we showed that the resistant ace-1R and the T alleles act in strong synergy, as they elicited a resistance 100 times higher than expected from a simple multiplicative effect. This effect was specific to chlorpyrifos and parathion and was not affected by synergists. We also examined how HCR was expressed in strains carrying other ace-1-resistant alleles, such as ace-1V or the duplicated ace-1D allele, currently spreading worldwide. We identified two major parameters that influenced the level of resistance: the number and the nature of the ace-1-resistant alleles and the number of T alleles. Our data fit a model that predicts that the T allele acts by decreasing chlorpyrifos concentration in the compartment targeted in insects. PMID:26463842

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.

Comparative analysis of gut microbiota of Culex restuans (Diptera: Culicidae) females from different parents

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The potential for gut microbiota to impede or enhance pathogen transmission is well-documented but the factors that shape this microbiota in mosquito vectors are poorly understood. We characterized and compared the gut microbiota of adult females of Culex restuans Theobald from different parents. Cu...

Primary blood-hosts of mosquitoes are influenced by social and ecological conditions in a complex urban landscape.

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Goodman, Heather; Egizi, Andrea; Fonseca, Dina M; Leisnham, Paul T; LaDeau, Shannon L

2018-04-10

Temperate urban landscapes support persistent and growing populations of Culex and Aedes mosquito vectors. Large urban mosquito populations can represent a significant risk for transmission of emergent arboviral infection. However, even large mosquito populations are only a risk to the animals they bite. The purpose of this study is to identify and assess spatial patterns of host-use in a temperate urban landscape with heterogeneous socio-economic and ecological conditions. Mosquito blood meals were collected from neighborhoods categorized along a socio-economic gradient in Baltimore, MD, USA. Blood meal hosts were identified for two Aedes (Ae. albopictus and Ae. japonicus) and three Culex (Cx. pipiens, Cx. restuans and Cx. salinarius) species. The brown rat (Rattus norvegicus) was the most frequently detected host in both Aedes species and Cx. salinarius. Human biting was evident in Aedes and Culex species and the proportion of human blood meals from Ae. albopictus varied significantly with neighborhood socio-economic status. Aedes albopictus was most likely to feed on human blood hosts (at 50%) in residential blocks categorized as having income above the city median, although there were still more total human bites detected from lower income blocks where Ae. albopictus was more abundant. Birds were the most frequently detected Culex blood hosts but were absent from all Aedes sampled. This study highlights fine-scale variation in host-use by medically important mosquito vectors and specifically investigates blood meal composition at spatial scales relevant to urban mosquito dispersal and human exposure. Further, the work emphasizes the importance of neighborhood economics and infrastructure management in shaping both the relative abundance of vectors and local blood feeding strategies. The invasive brown rat was an important blood source across vector species and neighborhoods in Baltimore. We show that social and economic conditions can be important predictors of

Novel synthesis of silver nanoparticles using Bauhinia variegata: a recent eco-friendly approach for mosquito control.

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Govindarajan, Marimuthu; Rajeswary, Mohan; Veerakumar, Kaliyan; Muthukumaran, Udaiyan; Hoti, S L; Mehlhorn, Heinz; Barnard, Donald R; Benelli, Giovanni

2016-02-01

Mosquito vectors are responsible for transmitting diseases such as malaria, dengue, chikungunya, Japanese encephalitis, dengue, and lymphatic filariasis. The use of synthetic insecticides to control mosquito vectors has caused physiological resistance and adverse environmental effects, in addition to high operational cost. Biosynthesis of silver nanoparticles has been proposed as an alternative to traditional control tools. In the present study, green synthesis of silver nanoparticles (AgNPs) using aqueous leaf extract of Bauhinia variegata by reduction of Ag(+) ions from silver nitrate solution has been investigated. The bioreduced silver nanoparticles were characterized by UV–visible spectrophotometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), and X-ray diffraction analysis (XRD). Leaf extract and synthesized AgNPs were evaluated against the larvae of Anopheles subpictus, Aedes albopictus, and Culex tritaeniorhynchus. Compared to aqueous extract, synthesized AgNPs showed higher toxicity against An. subpictus, Ae. albopictus, and Cx. tritaeniorhynchus with LC50 and LC90 values of 41.96, 46.16, and 51.92 μg/mL and 82.93, 89.42, and 97.12 μg/mL, respectively. Overall, this study proves that B. variegata is a potential bioresource for stable, reproducible nanoparticle synthesis and may be proposed as an efficient mosquito control agent.

Asymmetrical Competition between Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae Coexisting in Breeding Sites

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Juan C. Santana-Martínez

2017-10-01

Full Text Available Aedes aegypti and Culex quinquefasciatus are mosquito vectors for several tropical diseases that represent a current public health problem. The ecological requirements for each species are different, however, both species show high biological adaptability, which promotes their coexistence in the same breeding sites. The purpose of this study was to assess the effect of larval association between Ae. aegypti and Cx. quinquefasciatus under different laboratory conditions of food supply and temperature, and under field simulated conditions like peridomestic containers. Our findings showed that under field simulated conditions there was no asymmetrical competition in mixed cultures with the different Cx. quinquefasciatus/Ae. aegypti ratios tested. However, under laboratory conditions in which different doses of food supply were evaluated, it was observed that competition between the two species takes place. Larval coexistence under food scarcity conditions (0.95 mg/larva showed that Ae. aegypti had a greater adult emergence than Cx. quinquefasciatus and was capable of depriving Cx. quinquefasciatus of the food needed to complete metamorphosis. In an intermediate dose of food (1.9 mg/larva, the dry weight of Cx. quinquefasciatus adults decreased, and their larval development time increased when Cx. quinquefasciatus/Ae. aegypti ratio was low. Also, a temperature effect was assessed demonstrating that Cx. quinquefasciatus was more vulnerable to changes in temperature. We suggest that Ae. aegypti is more successful in exploiting microhabitats when food is scarce, due to its scrape active feeding habitats and fast larval development times. Therefore, in conditions of food paucity both species will compete, and Ae. aegypti larvae will prevail.

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

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Rosilainy Surubi Fernandes

2016-09-01

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

A mosquito hemolymph odorant-binding protein family member specifically binds juvenile hormone

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Kim, Il Hwan; Pham, Van; Jablonka, Willy; Goodman, Walter G.; Ribeiro, José M. C.; Andersen, John F.

2017-07-27

Juvenile hormone (JH) is a key regulator of insect development and reproduction. In adult mosquitoes, it is essential for maturation of the ovary and normal male reproductive behavior, but how JH distribution and activity is regulated after secretion is unclear. Here, we report a new type of specific JH-binding protein, given the name mosquito juvenile hormone-binding protein (mJHBP), which circulates in the hemolymph of pupal and adult Aedes aegypti males and females. mJHBP is a member of the odorant-binding protein (OBP) family, and orthologs are present in the genomes of Aedes, Culex, and Anopheles mosquito species. Using isothermal titration calorimetry, we show that mJHBP specifically binds JH II and JH III but not eicosanoids or JH derivatives. mJHBP was crystallized in the presence of JH III and found to have a double OBP domain structure reminiscent of salivary “long” D7 proteins of mosquitoes. We observed that a single JH III molecule is contained in the N-terminal domain binding pocket that is closed in an apparent conformational change by a C-terminal domain-derived α-helix. The electron density for the ligand indicated a high occupancy of the natural 10R enantiomer of JH III. Of note, mJHBP is structurally unrelated to hemolymph JHBP from lepidopteran insects. A low level of expression of mJHBP in Ae. aegypti larvae suggests that it is primarily active during the adult stage where it could potentially influence the effects of JH on egg development, mating behavior, feeding, or other processes.

A mosquito hemolymph odorant-binding protein family member specifically binds juvenile hormone.

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Kim, Il Hwan; Pham, Van; Jablonka, Willy; Goodman, Walter G; Ribeiro, José M C; Andersen, John F

2017-09-15

Juvenile hormone (JH) is a key regulator of insect development and reproduction. In adult mosquitoes, it is essential for maturation of the ovary and normal male reproductive behavior, but how JH distribution and activity is regulated after secretion is unclear. Here, we report a new type of specific JH-binding protein, given the name mosquito juvenile hormone-binding protein (mJHBP), which circulates in the hemolymph of pupal and adult Aedes aegypti males and females. mJHBP is a member of the odorant-binding protein (OBP) family, and orthologs are present in the genomes of Aedes , Culex , and Anopheles mosquito species. Using isothermal titration calorimetry, we show that mJHBP specifically binds JH II and JH III but not eicosanoids or JH derivatives. mJHBP was crystallized in the presence of JH III and found to have a double OBP domain structure reminiscent of salivary "long" D7 proteins of mosquitoes. We observed that a single JH III molecule is contained in the N-terminal domain binding pocket that is closed in an apparent conformational change by a C-terminal domain-derived α-helix. The electron density for the ligand indicated a high occupancy of the natural 10 R enantiomer of JH III. Of note, mJHBP is structurally unrelated to hemolymph JHBP from lepidopteran insects. A low level of expression of mJHBP in Ae. aegypti larvae suggests that it is primarily active during the adult stage where it could potentially influence the effects of JH on egg development, mating behavior, feeding, or other processes.

Local extinction of the Asian tiger mosquito (Aedes albopictus) following rat eradication on Palmyra Atol

Science.gov (United States)

Lafferty, Kevin D.; McLaughlin, John P.; Gruner, Daniel S.; Bogar, Taylor A.; Bui, An; Childress, Jasmine N.; Espinoza, Magaly; Forbes, Elizabeth S.; Johnston, Cora A.; Klope, Maggie; Kuile, Ana Miller-ter; Lee, Michelle; Plummer, Katherine A.; Weber, David A.; Young, Ronald T.; Young, Hillary S.

2018-01-01

The Asian tiger mosquito, Aedes albopictus, appears to have been extirpated from Palmyra Atoll following rat eradication. Anecdotal biting reports, collection records, and regular captures in black-light traps showed the species was present before rat eradication. Since then, there have been no biting reports and no captures over 2 years of extensive trapping (black-light and scent traps). By contrast, the southern house mosquito, Culex quinquefasciatus, was abundant before and after rat eradication. We hypothesize that mammals were a substantial and preferred blood meal for Aedes, whereas Culex feeds mostly on seabirds. Therefore, after rat eradication, humans and seabirds alone could not support positive population growth or maintenance of Aedes. This seems to be the first documented accidental secondary extinction of a mosquito. Furthermore, it suggests that preferred host abundance can limit mosquito populations, opening new directions for controlling important disease vectors that depend on introduced species like rats.

Temperature, viral genetics, and the transmission of West Nile virus by Culex pipiens mosquitoes.

Directory of Open Access Journals (Sweden)

A Marm Kilpatrick

2008-06-01

Full Text Available The distribution and intensity of transmission of vector-borne pathogens can be strongly influenced by the competence of vectors. Vector competence, in turn, can be influenced by temperature and viral genetics. West Nile virus (WNV was introduced into the United States of America in 1999 and subsequently spread throughout much of the Americas. Previously, we have shown that a novel genotype of WNV, WN02, first detected in 2001, spread across the US and was more efficient than the introduced genotype, NY99, at infecting, disseminating, and being transmitted by Culex mosquitoes. In the current study, we determined the relationship between temperature and time since feeding on the probability of transmitting each genotype of WNV. We found that the advantage of the WN02 genotype increases with the product of time and temperature. Thus, warmer temperatures would have facilitated the invasion of the WN02 genotype. In addition, we found that transmission of WNV accelerated sharply with increasing temperature, T, (best fit by a function of T(4 showing that traditional degree-day models underestimate the impact of temperature on WNV transmission. This laboratory study suggests that both viral evolution and temperature help shape the distribution and intensity of transmission of WNV, and provides a model for predicting the impact of temperature and global warming on WNV transmission.

Prevalence and distribution of pox-like lesions, avian malaria, and mosquito vectors in Kipahulu valley, Haleakala National Park, Hawai'i, USA

Science.gov (United States)

Aruch, Samuel; Atkinson, Carter T.; Savage, Amy F.; LaPointe, Dennis

2007-01-01

We determined prevalence and altitudinal distribution of introduced avian malarial infections (Plasmodium relictum) and pox-like lesions (Avipoxvirus) in forest birds from Kīpahulu Valley, Haleakalā National Park, on the island of Maui, and we identified primary larval habitat for the mosquito vector of this disease. This intensively managed wilderness area and scientific reserve is one of the most pristine areas of native forest remaining in the state of Hawai‘i, and it will become increasingly important as a site for restoration and recovery of endangered forest birds. Overall prevalence of malarial infections in the valley was 8% (11/133) in native species and 4% (4/101) in nonnative passerines; prevalence was lower than reported for comparable elevations and habitats elsewhere in the state. Infections occurred primarily in ‘Apapane (Himatione sanguinea) and Hawai‘i ‘Amakihi (Hemignathus virens) at elevations below 1,400 m. Pox-like lesions were detected in only two Hawai‘i ‘Amakihi (2%; 2/94) at elevations below 950 m. We did not detect malaria or pox in birds caught at 1,400 m in upper reaches of the valley. Adult mosquitoes (Culex quinquefasciatus) were captured at four sites at elevations of 640, 760, 915, and 975 m, respectively. Culex quinquefasciatus larvae were found only in rock holes along intermittent tributaries of the two largest streams in the valley, but not in standing surface water, pig wallows, ground pools, tree cavities, and tree fern cavities. Mosquito populations in the valley are low, and they are probably influenced by periods of high rainfall that flush stream systems.

LABORATORY EVALUATION OF ANDALIN, AN INSECT GROWTH REGULATOR INTERFERING WITH CUTICLE DEPOSITION, AGAINST MOSQUITO LARVAE

Directory of Open Access Journals (Sweden)

N REHIMI

2002-12-01

Full Text Available Andalin, a benzoylphenylurea (BPU derivative, was evaluated on Culex pipiens L. (Diptera: Culicidae. Treatment was made on newly 3rd- and 4th instar larvae for 24 h. The compound exhibited insecticidal activity and mortality occured after earlier inhibition of their development or by their inability to complete their ecdysis. Treatment resulted in a significant larvicidal effect and in a inhibition of adult emergence. Moreover, the compound disturbed growth and development since several morphological types and an increase in the duration of larval stage were observed. Histological study conducted on 4th instar larval integument, showed that Andalin caused a significant reduction in the thickness of cuticles secreted compared to controls. Thus, Andalin prevent molting in C. pipiens by interfering with cuticle deposition confirming the primary mode of action of this BPU insecticide.

Deteksi Brugia malayi pada Armigeres subalbatus dan Culex quinquefasciatusyang diinfeksikan darah penderita filariasis dengan metode PCR

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Yahya Yahya

2015-01-01

Full Text Available Abstract. Pemayungdistricts, Batanghari regency of Jambi province classified as filariasis endemic areas in Jambi province since the Mf rate reached 1.5% in 2011. A study was conducted to identify Brugia malayi on experimentally infected Ar. subalbatus and Cx. quinquefasciatus. An experimental study was performed with completely randomized design and six repetitions. Standard of treatment in this study was time (hours that selected for mosquitoes to bite the patients with filariasis (experimental infection. Selected time is at 9.00 a.m, 5.00 p.m, 9.00 p.m, and at 1.00 a.m. The results showed that filarial L3 larvae did not found on Ar. subalbatus and Cx. quinquefasciatus mosquitoes during surgery at day 11th to 13th after infection. Density of microfilariae in the blood of humans as a source of infection was 17 microfilariae per 20 micro liter blood. Otherwise, after detection by PCR, our study found positive B.malayi on Cx. quinquefasciatus thorax and proboscis. It indicates that Cx. quinquefasciatusas potential vector of B.malayi filariasis compared to Ar. subalbatus. Keywords: PCR, filariasis, Armigeres subalbatus, Culex quinquefasciatus, Brugia malayi   Abstrak. Kecamatan Pemayung Kabupaten Batanghari Provinsi Jambi merupakan wilayah endemis filariasis di Provinsi Jambi Karena angka Mf rate mencapai 1,5% pada tahun 2011. Penelitian ini untuk mengetahui tingkat kerentanan nyamuk Ar. subalbatus dan Cx. quinquefasciatus terhadap infeksi B. malayi subperiodik nokturna yang dilakukan pada tahun 2013, sehingga dapat dianalisis potensi nyamuk tersebut sebagai vektor filariasis di lokasi penelitian. Desain penelitian adalah eksperimental dengan rancangan acak lengkap dan enam kali pengulangan. Variabel perlakuan dalam penelitian ini adalah waktu (jam yang dipilih untuk menggigitkan nyamuk pada penderita filariasis (infeksi percobaan. Waktu yang dipilih adalah pukul 09.00 WIB, pukul 17.00 WIB, pukul 21.00 WIB dan pukul 01.00 WIB. Hasil penelitian

Distribution of Aedes mosquitoes in the Kilimanjaro Region of northern Tanzania.

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Hertz, Julian T; Lyaruu, Lucille J; Ooi, Eng Eong; Mosha, Franklin W; Crump, John A

2016-05-01

Little is known about the presence and distribution of Aedes mosquitoes in northern Tanzania despite the occurence of viruses transmitted by these mosquitoes such as Chikungunya virus (CHIKV) and Dengue virus (DENV) in the region. Adult and larval mosquitoes were collected from rural and urban settings across a wide range of altitudes in the Kilimanjaro Region using the Mosquito Magnet CO2 Trap for collection of adults and old tires for breeding of larvae. Polymerase chain reaction assays were performed on captured adult mosquitoes to detect the presence of CHIKV and DENV. A total of 2609 Aedes aegypti adult mosquitoes were collected; no other Aedes species larvae were found. Mosquito yields were significantly higher in urban settings than rural settings (26.5 vs. 1.9 mosquitoes per day, p = 0.037). A total of 6570 Ae. aegypti larvae were collected from old tires; no other Aedes species larvae were found. Of the 2609 adult mosquitoes collected, none tested positive for CHIKV or DENV. As far as we are aware, this paper reports for the first time the presence of Ae. aegypti in the Kilimanjaro Region of northern Tanzania. Although CHIKV and DENV were not isolated from any of the collected mosquitoes in this study, the apparent absence of other Aedes species in the area suggests that Ae. aegypti is the primary local vector of these infections.

St. Louis Encephalitis virus mosquito vectors dynamics in three different environments in relation to remotely sensed environmental conditions.

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Batallán, Gonzalo P; Estallo, Elizabet L; Flores, Fernando S; Sartor, Paolo; Contigiani, Marta S; Almirón, Walter R

2015-06-01

In Argentina the St. Louis Encephalitis virus (SLEV) is an endemic and widely distributed pathogen transmitted by the cosmopolitan mosquito Culex quinquefasciatus. During two outbreaks in Córdoba city, in 2005 and 2010, Culex interfor was also found infected, but its role as vector of SLEV is poorly known. This mosquito species is distributed from central Argentina to southern Brazil. The primary aim of this study was to analyze the population dynamic of Cx. interfor and Cx. quinquefasciatus in three different environments (urban, suburban and non-urban) in relation to remotely sensed environmental data for vegetation (NDVI and NDWI) and temperature (brightness temperature). Cx. quinquefasciatus and Cx. interfor were found at the three sampled sites, being both the most abundant Culex species, with peaks in early and midsummer. Temporal distribution patterns of both mosquito species were highly correlated in a non-urban area of high SLEV risk transmission. Cx. quinquefasciatus and Cx. interfor were associated with the most urbanized site and the non-urban environment, respectively; high significant correlations were detected between vegetation indices and abundance of both mosquito species confirming these associations. These data provide a foundation for building density maps of these two SLEV mosquito vectors using remotely sensed data to help inform vector control programs. Copyright © 2015 Elsevier B.V. All rights reserved.

Detection of West Nile virus-specific antibodies and nucleic acid in horses and mosquitoes, respectively, in Nuevo Leon State, northern Mexico, 2006-2007.

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Ibarra-Juarez, L; Eisen, L; Bolling, B G; Beaty, B J; Blitvich, B J; Sanchez-Casas, R M; Ayala-Sulca, Y O; Fernandez-Salas, I

2012-09-01

In the last 5 years, there has been only one reported human case of West Nile virus (WNV) disease in northern Mexico. To determine if the virus was still circulating in this region, equine and entomological surveillance for WNV was conducted in the state of Nuevo Leon in northern Mexico in 2006 and 2007. A total of 203 horses were serologically assayed for antibodies to WNV using an epitope-blocking enzyme-linked immunosorbent assay (bELISA). Seroprevalences for WNV in horses sampled in 2006 and 2007 were 26% and 45%, respectively. Mosquito collections in 2007 produced 7365 specimens representing 15 species. Culex mosquitoes were screened for WNV RNA and other genera (Mansonia, Anopheles, Aedes, Psorophora and Uranotaenia) were screened for flaviviruses using reverse-transcription (RT)-PCR. Two pools consisting of Culex spp. mosquitoes contained WNV RNA. Molecular species identification revealed that neither pool included Culex quinquefasciatus (Say) (Diptera:Culicidae) complex mosquitoes. No evidence of flaviviruses was found in the other mosquito genera examined. These data provide evidence that WNV is currently circulating in northern Mexico and that non-Cx. quinquefasciatus spp. mosquitoes may be participating in the WNV transmission cycle in this region. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

Prey preferences of aquatic insects: potential implications for the regulation of wetland mosquitoes.

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Saha, N; Aditya, G; Saha, G K

2014-03-01

Wetlands are potential sites for mosquito breeding and are thus important in the context of public health. The use of chemical and microbial controls is constrained in wetlands in view of their potential impact on the diverse biota. Biological control using generalist aquatic insects can be effective, provided a preference for mosquito larvae is exhibited. The mosquito prey preferences of water bugs and larvae of odonate species were evaluated using chironomid larvae, fish fingerlings and tadpoles as alternative prey. Manly's selectivity (αi ) values with 95% confidence intervals (CIs) were estimated to judge prey preference patterns. Multivariate analysis of variance (manova) and standardized canonical coefficients were used to test the effects of density on prey selectivity. The αi values indicated a significant preference (P insect predators tested for mosquito larvae over the alternative prey as a density-dependent function. On a comparative scale, chironomid larvae had the highest impact as alternative prey. In a multiple-prey experiment, predators showed a similar pattern of preference for mosquito larvae over alternative prey, reflecting a significant (P insect predators can effectively reduce mosquito density in the presence of multiple alternative prey. © 2013 The Royal Entomological Society.

Synthesis and characterization of silver nanoparticles using Bacillus amyloliquefaciens and Bacillus subtilis to control filarial vector Culex pipiens pallens and its antimicrobial activity.

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Fouad, Hatem; Hongjie, Li; Yanmei, Ding; Baoting, Yu; El-Shakh, Ahmed; Abbas, Ghulam; Jianchu, Mo

2017-11-01

Culex pipiens pallens are the most common mosquito's vector in Asia. In order to protect the people from diseases, the anti-mosquito population is necessary that uses safe and new bio-pesticides such as bacteria-AgNPs. In our report, we used two kinds of bacteria to synthesize silver nanoparticles to examine the toxic effect on the larvae and pupae of Cx. pipiens pallens and also used as antimicrobial activity. The biosynthesis of AgNPs and its characterization was carried out by UV-Vis spectrophotometry, FTIR, TEM, SEM, and EDX. The larvicidal and pupicidal assays revealed that the lethal concentration LC 50 values of Bacillus amyloliquefaciens-AgNPs were 0.72 ppm (I), 0.73 ppm (II), 0.69 ppm (III), 1.16 ppm (IV), and 4.18 (Pupae), while LC 50 values of Bacillus subtilis-AgNPs were 0.60 ppm (I), 0.62 ppm (II), 0.21 ppm (III), 0.28 ppm (IV), and 3.46 ppm (Pupae) after 72 h of exposure. Antibacterial activity test of AgNPs reveals better results against rice pathogenic bacteria than bacteria alone. Thus, bacteria-mediated silver nanoparticles have a rapid effect on vector mosquito and microbial pathogen suggesting savings of energy and resources. Hence, bacteria-AgNPs may be used in the future as an effective weapon to control vector mosquito and harmful bacteria.

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

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

2009-09-01

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

Eco-friendly larvicides from Indian plants: Effectiveness of lavandulyl acetate and bicyclogermacrene on malaria, dengue and Japanese encephalitis mosquito vectors.

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Govindarajan, Marimuthu; Benelli, Giovanni

2016-11-01

Mosquitoes (Diptera: Culicidae) are a key threat for millions of people and animals worldwide, since they act as vectors for devastating pathogens and parasites, including malaria, dengue, Japanese encephalitis, filiariasis and Zika virus. Mosquito young instars are usually targeted using organophosphates, insect growth regulators and microbial agents. Indoor residual spraying and insecticide-treated bed nets are also employed. However, these chemicals have negative effects on human health and the environment and induce resistance in a number of vectors. In this scenario, newer and safer tools have been recently implemented to enhance mosquito control. The concrete potential of screening plant species as sources of metabolites for entomological and parasitological purposes is worthy of attention, as recently elucidated by the Y. Tu's example. Here we investigated the toxicity of Heracleum sprengelianum (Apiaceae) leaf essential oil and its major compounds toward third instar larvae of the malaria vector Anopheles subpictus, the arbovirus vector Aedes albopictus and the Japanese encephalitis vector Culex tritaeniorhynchus. GC-MS analysis showed that EO major components were lavandulyl acetate (17.8%) and bicyclogermacrene (12.9%). The EO was toxic to A. subpictus, A. albopictus, and C. tritaeniorhynchus, with LC50 of 33.4, 37.5 and 40.9µg/ml, respectively. Lavandulyl acetate was more toxic to mosquito larvae if compared to bicyclogermacrene. Their LC50 were 4.17 and 10.3µg/ml for A. subpictus, 4.60 and 11.1µg/ml for A. albopictus, 5.11 and 12.5µg/ml for C. tritaeniorhynchus. Notably, the EO and its major compounds were safer to three non-target mosquito predators, Anisops bouvieri, Diplonychus indicus and Gambusia affinis, with LC50 ranging from 206 to 4219µg/ml. Overall, this study highlights that H. sprengelianum EO is a promising source of eco-friendly larvicides against three important mosquito vectors with moderate toxicity against non-target aquatic

Field evaluation of spatial repellency of metofluthrin impregnated plastic strips against mosquitoes in Hai Phong City, Vietnam.

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Kawada, Hitoshi; Yen, Nguyen Thi; Hoa, Nguyen Thuy; Sang, Truong Minh; VAN Dan, Nguyen; Takagi, Masahiro

2005-08-01

Spatial repellency of metofluthrin-impregnated polyethylene plastic strips against mosquitoes, Aedes aegypti and Culex quinquefasciatus, were studied in a residential area in Hai Phong city, Vietnam. Thirty houses were selected as trial sites; half of these were assigned as untreated control and the other half were assigned for treatment. Primarily, irrespective of the room size, one room was treated with one strip. The dominant species in the trial sites were Culex quinquefasciatus and Aedes aegypti. A rapid decrease in the mosquito index was observed immediately after the treatment with metofluthrin strips, and treatment was effective for at least 6 weeks.

Spatio-Temporal Distribution of Vector-Host Contact (VHC) Ratios and Ecological Niche Modeling of the West Nile Virus Mosquito Vector, Culex quinquefasciatus, in the City of New Orleans, LA, USA.

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Sallam, Mohamed F; Michaels, Sarah R; Riegel, Claudia; Pereira, Roberto M; Zipperer, Wayne; Lockaby, B Graeme; Koehler, Philip G

2017-08-08

The consistent sporadic transmission of West Nile Virus (WNV) in the city of New Orleans justifies the need for distribution risk maps highlighting human risk of mosquito bites. We modeled the influence of biophysical and socioeconomic metrics on the spatio-temporal distributions of presence/vector-host contact (VHC) ratios of WNV vector, Culex quinquefasciatus , within their flight range . Biophysical and socioeconomic data were extracted within 5-km buffer radii around sampling localities of gravid female Culex quinquefasciatus . The spatio-temporal correlations between VHC data and 33 variables, including climate, land use-land cover (LULC), socioeconomic, and land surface terrain were analyzed using stepwise linear regression models (RM). Using MaxEnt, we developed a distribution model using the correlated predicting variables. Only 12 factors showed significant correlations with spatial distribution of VHC ratios ( R ² = 81.62, p < 0.01). Non-forested wetland (NFWL), tree density (TD) and residential-urban (RU) settings demonstrated the strongest relationship. The VHC ratios showed monthly environmental resilience in terms of number and type of influential factors. The highest prediction power of RU and other urban and built up land (OUBL), was demonstrated during May-August. This association was positively correlated with the onset of the mosquito WNV infection rate during June. These findings were confirmed by the Jackknife analysis in MaxEnt and independently collected field validation points. The spatial and temporal correlations of VHC ratios and their response to the predicting variables are discussed.

Trial of spatial repellency of metofluthrin impregnated paper strip against Anopheles and Culex in shelters without walls in Lombok, Indonesia

OpenAIRE

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

2004-01-01

TriaIs of metofluthrin-impregnated multilayer paper strips against mosquitoes in shelters with no walls were carried out at 3 sites in Lombok, Indonesia. Major reductions in human biting by Culex quinquefasciatus,Anopheles balabacensis, and An. sundaicus were achieved. The device is a very praitical measure of preventing outdoor mosquito biting, with no need for electricity or heating to evaporate its active ingredient.

Trial of spatial repellency of metofluthrin-impregnated paper strip against Anopheles and Culex in shelters without walls in Lombok, Indonesia.

Science.gov (United States)

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

2004-12-01

Trials of metofluthrin-impregnated multilayer paper strips against mosquitoes in shelters with no walls were carried out at 3 sites in Lombok, Indonesia. Major reductions in human biting by Culex quinquefasciatus, Anopheles balabacensis, and An. sundaicus were achieved. The device is a very practical measure of preventing outdoor mosquito biting, with no need for electricity or heating to evaporate its active ingredient.

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

Micro x-ray absorption spectroscopic analysis of arsenic localization and biotransformation in Chironomus riparius Meigen (Diptera: Chironomidae) and Culex tarsalis Coquillett (Culicidae)

International Nuclear Information System (INIS)

Mogren, Christina L.; Webb, Samuel M.; Walton, William E.; Trumble, John T.

2013-01-01

The distribution and speciation of arsenic (As) were analyzed in individuals of various life stages of a midge, Chironomus riparius, and the mosquito Culex tarsalis exposed to 1000 μg/l arsenate. X-ray absorption spectroscopy (XAS) revealed that C. riparius larvae accumulate As in their midgut, with inorganic arsenate [As(V)] being the predominant form, followed by arsenite [As(III)] and an As-thiol. Reduced concentrations of As in pupal and adult stages of C. riparius indicate excretion of As between the larval and pupal stages. In adults, As was limited to the thorax, and the predominant form was an As-thiol. In Cx. tarsalis, As was not found in high enough concentrations to determine As speciation, but the element was distributed throughout the larva. In adults, As was concentrated in the thorax and eyes of adults. These results have implications for understanding the biotransformation of As and its movement from aquatic to terrestrial environments. -- Highlights: •C. riparius larvae reduced arsenate to arsenite in the midgut. •C. riparius larvae accumulated As in the midgut, with 27% as a transformed As-thiol. •C. riparius adults retained As in the thorax, with 53% as As-thiol. •Larvae of Cx. tarsalis did not have a specific site of As accumulation. •Low concentrations of As in adults suggest reduced terrestrial transfer potential. -- Arsenic accumulation and biotransformation in aquatic insects is variable, but the location and speciation of As provides insight into the detoxification mechanisms of aquatic Diptera

Host-Feeding Patterns of Culex stigmatosoma (Diptera: Culicidae) in Southern California.

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McPhatter, Lee P; Su, Tianyun; Williams, Greg; Cheng, Min-Lee; Dhillon, Major; Gerry, Alec C

2017-11-07

Knowledge of the blood-feeding patterns exhibited by arthropod vectors is essential for understanding the complex dynamics of vector-borne disease transmission. Some species of mosquitoes belonging to the genus Culex have been implicated as having major roles in the transmission of arboviruses such as West Nile virus, Saint Louis encephalitis virus, and Western equine encephalitis virus. Although the host-feeding patterns for many of these Culex species are well studied, the host-feeding patterns of Culex stigmatosoma Dyar are relatively poorly studied, even though this species is suspected to be an important maintenance vector for West Nile virus and other arboviruses. In the current study, bloodmeals from 976 blood-engorged Cx. stigmatosoma, collected from 30 sites in southern California from 2009-2012, were processed for vertebrate host identification by nucleotide sequencing following polymerase chain reaction to amplify portions of the cytochrome oxidase I and cytochrome b genes of vertebrate animals. Vertebrate DNA was amplified, sequenced, and identified from a total of 647 Cx. stigmatosoma bloodmeals, revealing that 98.6% of bloodmeals were from birds, 1.2% from three mammal species, and a single bloodmeal was from a reptile species. In total, 40 different host species were identified. The greatest number of bloodmeals identified was from domestic chicken (Gallus gallus domesticus L.) (38% of bloodmeals), house sparrow (Passer domesticus L.) (23%), house finch (Haemorhous mexicanus Müller) (17%), American crow (Corvus brachyrhynchos L.) (4%), and mourning dove (Zenaida macroura L.) (3%). However, chicken bloodmeals were identified almost entirely from a single site where mosquito collection devices were placed in the near vicinity of confined domestic chickens. The strongly ornithophilic feeding behavior shown in this study for Cx. stigmatosoma supports the hypothesis that this mosquito species may be an important maintenance (or endemic) vector for

The roles of mosquito and bird communities on the prevalence of West Nile virus in urban wetland and residential habitats

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Johnson, Brian J.; Munafo, Kristin; Shappell, Laura; Tsipoura, Nellie; Robson, Mark; Ehrenfeld, Joan; Sukhdeo, Michael V. K.

2014-01-01

This study investigated the impacts of urban wetlands and their adjacent residential environments on the transmission dynamics of West Nile virus (WNV) within the state of New Jersey (USA). A working hypothesis was that urban wetlands decrease the local prevalence of WNV through the dilution effect from increased bird diversity, and through relative reductions in the numbers of competent avian host and mosquito species commonly associated with WNV. Surveys of mosquito and bird communities were undertaken at six urban wetlands and their adjacent residential environments over two seasons (2009, 2010). The community compositions of both avian and mosquito species differed significantly across habitats, and over relatively short geographical distances. Residential areas contained significantly higher proportions of WNV-competent mosquito species (31.25±5.3 %; e.g. Culex pipiens and Culex restuans), and WNV-competent avian host species (62.8±2.3 %, e.g. House Sparrow and American Robin) when compared to adjacent urban wetlands (13.5±2.1 %; 35.4±2.1 % respectively). Correspondingly, WNV infection rates within local Culex spp. populations indicate that WNV was more prevalent within residential areas (28.53/1000) compared to wetlands (16.77/1000). Large urban wetlands (>100 ha) produced significantly lower weekly WNV infection rates in local Culex spp. (6.67±2.84/1000) compared to small (urban wetlands contained significantly more species than small wetland patches. These results confirm that the community compositions of mosquito and avian hosts are important drivers in WNV infections, and that the ecological conditions that favor transmission are more strongly associated with urban residential environments than with adjacent urban wetlands. PMID:25484570

Larval diet affects mosquito development and permissiveness to Plasmodium infection.

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Linenberg, Inbar; Christophides, George K; Gendrin, Mathilde

2016-12-02

The larval stages of malaria vector mosquitoes develop in water pools, feeding mostly on microorganisms and environmental detritus. Richness in the nutrient supply to larvae influences the development and metabolism of larvae and adults. Here, we investigated the effects of larval diet on the development, microbiota content and permissiveness to Plasmodium of Anopheles coluzzii. We tested three fish diets often used to rear mosquitoes in the laboratory, including two pelleted diets, Dr. Clarke's Pool Pellets and Nishikoi Fish Pellets, and one flaked diet, Tetramin Fish-Flakes. Larvae grow and develop faster and produce bigger adults when feeding on both types of pellets compared with flakes. This correlates with a higher microbiota load in pellet-fed larvae, in agreement with the known positive effect of the microbiota on mosquito development. Larval diet also significantly influences the prevalence and intensity of Plasmodium berghei infection in adults, whereby Nishikoi Fish Pellets-fed larvae develop into adults that are highly permissive to parasites and survive longer after infection. This correlates with a lower amount of Enterobacteriaceae in the midgut microbiota. Together, our results shed light on the influence of larval feeding on mosquito development, microbiota and vector competence; they also provide useful data for mosquito rearing.

Mosquitoes rely on their gut microbiota for development

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Coon, Kerri L.; Vogel, Kevin J.; Brown, Mark R.; Strand, Michael R.

2014-01-01

Field studies indicate adult mosquitoes (Culicidae) host low diversity communities of bacteria that vary greatly among individuals and species. In contrast, it remains unclear how adult mosquitoes acquire their microbiome, what influences community structure, and whether the microbiome is important for survival. Here we used pyrosequencing of 16S rRNA to characterize the bacterial communities of three mosquito species reared under identical conditions. Two of these species, Aedes aegypti and Anopheles gambiae, are anautogenous and must blood feed to produce eggs, while one, Georgecraigius atropalpus, is autogenous and produces eggs without blood feeding. Each mosquito species contained a low diversity community comprised primarily of aerobic bacteria acquired primarily from the aquatic habitat in which larvae developed. Our results suggested the communities in Ae. aegypti and An. gambiae larvae share more similarities with one another than with Ge. atropalpus. Studies with Ae. aegypti also strongly suggested that adults transstadially acquired several members of the larval bacterial community, but only four genera of bacteria present in blood fed females were detected on eggs. Functional assays showed that axenic larvae of each species failed to develop beyond the first instar. Experiments with Ae. aegypti indicated several members of the microbial community and Escherichia coli successfully colonized axenic larvae and rescued development. Overall, our results provide new insights about the acquisition and structure of bacterial communities in mosquitoes. They also indicate three mosquito species spanning the breadth of the Culicidae depend on their gut microbiome for development. PMID:24766707

Distribution of mosquitoes and mosquito-borne arboviruses in Yunnan Province near the China-Myanmar-Laos border.

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Wang, Jinglin; Zhang, Hailin; Sun, Xiaohong; Fu, Shihong; Wang, Huanqin; Feng, Yun; Wang, Huanyu; Tang, Qing; Liang, Guo-Dong

2011-05-01

Economic development and increased tourism in the southern region of Yunnan Province in China, adjacent to several countries in Southeast Asia, has increased the likelihood of import and export of vectors and vector-borne diseases. We report the results of surveillance of mosquitoes and mosquito-borne arboviruses along the border of China-Myanmar-Laos in 2005 and 2006, and information associating several arboviruses with infections and possibly disease in local human populations. Seventeen mosquito species representing four genera were obtained, and 14 strains of mosquito-borne viruses representing six viruses in five genera were isolated from Culex tritaeniorhynchus. In addition, IgM against Japanese encephalitis virus, Sindbis virus, Yunnan orbivirus and novel Banna virus was detected in acute-phase serum samples obtained from hospitalized patients with fever and encephalitis near the areas where the viruses were isolated. This investigation suggests that Japanese encephalitis virus, Sindbis virus, and lesser-known arboviruses circulate and may be infecting humans in the China-Myanmar-Laos border region.

Operational Evaluation Of Vectomax® WSP (Bacillus thuringiensis Subsp. israelensis+Bacillus sphaericus) Against Larval Culex pipiens in Septic Tanks (1).

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

2015-06-01

The residual effectiveness of VectoMax® WSP (a water-soluble pouch formulation containing a combination of Bacillus thuringiensis subsp. israelensis strain AM65-52 and B. sphaericus strain ABTS 1743) when applied to septic tanks against 3rd- and 4th-stage larvae of Culex pipiens L. was evaluated in this study. This formulation was evaluated at operational application rates of 1 pouch (10 g) and 2 pouches (20 g) per septic tank. Both application rates resulted in >96% control of larvae for 24 days. Operationally, VectoMax WSP has proven to be a useful tool for the nonchemical control of Culex species in septic tank environments.

British Container Breeding Mosquitoes: The Impact of Urbanisation and Climate Change on Community Composition and Phenology

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Townroe, Susannah; Callaghan, Amanda

2014-01-01

The proliferation of artificial container habitats in urban areas has benefitted urban adaptable mosquito species globally. In areas where mosquitoes transmit viruses and parasites, it can promote vector population productivity and fuel mosquito-borne disease outbreaks. In Britain, storage of water in garden water butts is increasing, potentially expanding mosquito larval habitats and influencing population dynamics and mosquito-human contact. Here we show that the community composition, abundance and phenology of mosquitoes breeding in experimental water butt containers were influenced by urbanisation. Mosquitoes in urban containers were less species-rich but present in significantly higher densities (100.4±21.3) per container than those in rural containers (77.7±15.1). Urban containers were dominated by Culex pipiens (a potential vector of West Nile Virus [WNV]) and appear to be increasingly exploited by Anopheles plumbeus (a human-biting potential WNV and malaria vector). Culex phenology was influenced by urban land use type, with peaks in larval abundances occurring earlier in urban than rural containers. Among other factors, this was associated with an urban heat island effect which raised urban air and water temperatures by 0.9°C and 1.2°C respectively. Further increases in domestic water storage, particularly in urban areas, in combination with climate changes will likely alter mosquito population dynamics in the UK. PMID:24759617

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

OpenAIRE

V. Thenmozhi; T. Mariappan; R. Krishnamoorthy; R. Krishnamoorthi; T. Balaji; B. K. Tyagi; V. Thenmozhi

2014-01-01

Japanese encephalitis (JE) is endemic in many parts of India including the state of West Bengal. In West Bengal, the first major outbreaks of JE occurred in the districts of Bankura and Burdwan in 1973. The Culex vishnui subgroup of mosquitoes has been implicated as major vectors of JE. However in India, JE virus (JEV) has been isolated from 16 species of mosquitoes. During September 2011, JE cases were reported from four districts -Jalpaiguri, Darjeeling, Dinajpur and Cooch Behar of West Ben...

Sporulation of Bacillus sphaericus 2297: an electron microscope study of crystal-like inclusion biogenesis and toxicity to mosquito larvae.

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Kalfon, A; Charles, J F; Bourgouin, C; de Barjac, H

1984-04-01

Sporulation of Bacillus sphaericus strain 2297 in a synchronous liquid culture was studied by electron microscopy. The t0 of sporulation occurred 7 h after the beginning of the lag phase. Crystal-like inclusions first appeared at t2 and reached their final size between t5 and t6. The release of the spore/inclusion complex occurred at about t15 (22 h after inoculation). Toxicity against Culex pipiens larvae was related to sporulation and appeared during the early stages of sporulation. The LC50 (24 h) decreased about 10(5)-fold between t0-2 and t7, in correlation with the formation of crystalline inclusions. Heat resistance of spores appeared later than toxicity.

QTL mapping of genome regions controlling temephos resistance in larvae of the mosquito Aedes aegypti.

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Reyes-Solis, Guadalupe Del Carmen; Saavedra-Rodriguez, Karla; Suarez, Adriana Flores; Black, William C

2014-10-01

The mosquito Aedes aegypti is the principal vector of dengue and yellow fever flaviviruses. Temephos is an organophosphate insecticide used globally to suppress Ae. aegypti larval populations but resistance has evolved in many locations. Quantitative Trait Loci (QTL) controlling temephos survival in Ae. aegypti larvae were mapped in a pair of F3 advanced intercross lines arising from temephos resistant parents from Solidaridad, México and temephos susceptible parents from Iquitos, Peru. Two sets of 200 F3 larvae were exposed to a discriminating dose of temephos and then dead larvae were collected and preserved for DNA isolation every two hours up to 16 hours. Larvae surviving longer than 16 hours were considered resistant. For QTL mapping, single nucleotide polymorphisms (SNPs) were identified at 23 single copy genes and 26 microsatellite loci of known physical positions in the Ae. aegypti genome. In both reciprocal crosses, Multiple Interval Mapping identified eleven QTL associated with time until death. In the Solidaridad×Iquitos (SLD×Iq) cross twelve were associated with survival but in the reciprocal IqxSLD cross, only six QTL were survival associated. Polymorphisms at acetylcholine esterase (AchE) loci 1 and 2 were not associated with either resistance phenotype suggesting that target site insensitivity is not an organophosphate resistance mechanism in this region of México. Temephos resistance is under the control of many metabolic genes of small effect and dispersed throughout the Ae. aegypti genome.

Entomologic investigations of an epidemic of St. Louis encephalitis in Pine Bluff, Arkansas, 1991.

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Savage, H M; Smith, G C; Moore, C G; Mitchell, C J; Townsend, M; Marfin, A A

1993-07-01

An epidemic of St. Louis encephalitis (SLE) occurred in Jefferson County, Arkansas during July-August 1991. At least 26 human cases were involved, with 25 cases in the town of Pine Bluff. Twelve isolates of SLE virus were obtained from mosquitoes collected in Pine Bluff between August 13 and 24: 11 from pools of Culex pipiens quinquefasciatus, resulting in a minimum infection rate of 1.6 per 1,000 (n = 6,768) for this subspecies, and one isolate from a pool of 22 mosquitoes identified as Cx. (Culex) spp. Three of the SLE-positive pools, two from Cx. p. quinquefasciatus and one from Cx. (Cux.) spp., also yielded isolates of Flanders virus. Larval surveys resulted in the collection of seven species in four genera from 28 larva-positive habitats and the identification of one significant site of Cx. p. quinquefasciatus production. Ecologic assessments conducted at 12 randomly selected residences resulted in the identification of 17 larva-positive habitats, for an average mosquito-positive habitat rate of 1.4 per residence, and a Cx. p. quinquefasciatus larva-positive habitat rate of 0.6 per residence. Aedes albopictus and Cx. p. quinquefasciatus were the species most frequently encountered in larval surveys in residential neighborhoods.

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

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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

Efficacy of fipronil-(S)-methoprene, metaflumizone combined with amitraz, and pyriprole commercial spot-on products in preventing Culex pipiens pipiens from feeding on dogs.

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Bouhsira, E; Fysikopoulos, A; Franc, M

2009-08-01

A controlled clinical trial was carried out to assess the effectiveness of pyriprole, metaflumizone combined with amitraz, and fipronil-(S)-methoprene commercial spot-on products in preventing adult female Culex pipiens pipiens from feeding on dogs. Twenty-four beagle dogs were tested for their attractiveness to the mosquitoes and ranked accordingly to produce four groups of equivalent sensitivity to mosquitoes; six were treated with the pyriprole spot-on, six with the metaflumizone combined with amitraz spot-on, six with the fipronil-(S)-methoprene spot-on, and six were left untreated. All the dogs were challenged with 50 unfed adult female Culex in cages for one hour seven days before the treatment, and one and seven days after it. The mosquitoes were checked for blood feeding after one hour and for mortality 24 hours after they had been released into the cages. There was a significant reduction in the number of engorged mosquitoes only with the fipronil-(S)-methoprene product and there were significantly more dead mosquitoes with this product and the pyriprole product, but their effects were too small for them to be recommended for use in a dirofilariosis prevention programme.

Experimental hut evaluation of bednets treated with an organophosphate (chlorpyrifos-methyl or a pyrethroid (lambdacyhalothrin alone and in combination against insecticide-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes

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Corbel Vincent

2005-05-01

Full Text Available Abstract Background Pyrethroid resistant mosquitoes are becoming increasingly common in parts of Africa. It is important to identify alternative insecticides which, if necessary, could be used to replace or supplement the pyrethroids for use on treated nets. Certain compounds of an earlier generation of insecticides, the organophosphates may have potential as net treatments. Methods Comparative studies of chlorpyrifos-methyl (CM, an organophosphate with low mammalian toxicity, and lambdacyhalothrin (L, a pyrethroid, were conducted in experimental huts in Côte d'Ivoire, West Africa. Anopheles gambiae and Culex quinquefasciatus mosquitoes from the area are resistant to pyrethroids and organophosphates (kdr and insensitive acetylcholinesterase Ace.1R. Several treatments and application rates on intact or holed nets were evaluated, including single treatments, mixtures, and differential wall/ceiling treatments. Results and Conclusion All of the treatments were effective in reducing blood feeding from sleepers under the nets and in killing both species of mosquito, despite the presence of the kdr and Ace.1R genes at high frequency. In most cases, the effects of the various treatments did not differ significantly. Five washes of the nets in soap solution did not reduce the impact of the insecticides on A. gambiae mortality, but did lead to an increase in blood feeding. The three combinations performed no differently from the single insecticide treatments, but the low dose mixture performed encouragingly well indicating that such combinations might be used for controlling insecticide resistant mosquitoes. Mortality of mosquitoes that carried both Ace.1R and Ace.1S genes did not differ significantly from mosquitoes that carried only Ace.1S genes on any of the treated nets, indicating that the Ace.1R allele does not confer effective resistance to chlorpyrifos-methyl under the realistic conditions of an experimental hut.

Unraveling Host-Vector-Arbovirus Interactions by Two-Gene High Resolution Melting Mosquito Bloodmeal Analysis in a Kenyan Wildlife-Livestock Interface.

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David Omondi

Full Text Available The blood-feeding patterns of mosquitoes are directly linked to the spread of pathogens that they transmit. Efficient identification of arthropod vector bloodmeal hosts can identify the diversity of vertebrate species potentially involved in disease transmission cycles. While molecular bloodmeal analyses rely on sequencing of cytochrome b (cyt b or cytochrome oxidase 1 gene PCR products, recently developed bloodmeal host identification based on high resolution melting (HRM analyses of cyt b PCR products is more cost-effective. To resolve the diverse vertebrate hosts that mosquitoes may potentially feed on in sub-Saharan Africa, we utilized HRM profiles of both cyt b and 16S ribosomal RNA genes. Among 445 blood-fed Aedeomyia, Aedes, Anopheles, Culex, Mansonia, and Mimomyia mosquitoes from Kenya's Lake Victoria and Lake Baringo regions where many mosquito-transmitted pathogens are endemic, we identified 33 bloodmeal hosts including humans, eight domestic animal species, six peridomestic animal species and 18 wildlife species. This resolution of vertebrate host species was only possible by comparing profiles of both cyt b and 16S markers, as melting profiles of some pairs of species were similar for either marker but not both. We identified mixed bloodmeals in a Culex pipiens from Mbita that had fed on a goat and a human and in two Mansonia africana mosquitoes from Baringo that each had fed on a rodent (Arvicanthis niloticus in addition to a human or baboon. We further detected Sindbis and Bunyamwera viruses in blood-fed mosquito homogenates by Vero cell culture and RT-PCR in Culex, Aedeomyia, Anopheles and Mansonia mosquitoes from Baringo that had fed on humans and livestock. The observed mosquito feeding on both arbovirus amplifying hosts (including sheep and goats and possible arbovirus reservoirs (birds, porcupine, baboons, rodents informs arbovirus disease epidemiology and vector control strategies.

Mosquito (Diptera: Culicidae Habitat Surveillance by Android Mobile Devices in Guangzhou, China

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Tai-Ping Wu

2016-12-01

Full Text Available In 2014, Guangzhou City, South China, suffered from its worst outbreak of dengue fever in decades. Larval mosquito habitat surveillance was carried out by using android mobile devices in four study sites in May 2015. The habitats with larval mosquitoes were recorded as photo waypoints in OruxMaps or in videos. The total number of potential mosquito habitats was 342, of which 166 (49% were found to have mosquito larvae or pupae. Small containers were the most abundant potential habitats, accounting for 26% of the total number. More mosquito larvae and pupae, were found in small containers than in other objects holding water, for example, potted or hydroponic plants (p < 0.05. Mosquito larvae were collected from all plastic road barriers, used tires, and underground water. Aedes albopictus larvae were found from small and large containers, stumps, among others. The overall route index (RI was 11.3, which was 14.2 times higher than the grade C criteria of the National Patriotic Health Campaign Committee (NPHCC, China. The higher RIs were found from the bird and flower markets, schools, and underground parking lots. The results indicated that Android mobile devices are a convenient and useful tool for surveillance of mosquito habitats, and the enhancement of source reduction may benefit the prevention and control of dengue vector mosquitoes.

Transfer of toxin genes to alternate bacterial hosts for mosquito control

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Sergio Orduz

1995-02-01

Full Text Available Mosquitoes are vector of serious human and animal diseases, such as malaria, dengue, yellow fever, among others. The use of biological control agents has provide an environmentally safe and highly specific alternative to the use of chemical insecticides in the control of vector borne diseases. Bacillus thuringiensis and B. sphaericus produce toxic proteins to mosquito larvae. Great progress has been made on the biochemical and molecular characterization of such proteins and the genes encoding them. Nevertheless, the low residuality of these biological insecticides is one of the major drawbacks. This article present some interesting aspects of the mosquito larvae feeding habits and review the attempts that have been made to genetically engineer microorganisms that while are used by mosquito larvae as a food source should express the Bacillus toxin genes in order to improve the residuality and stability in the mosquito breeding ponds.

Polymer nanoparticles containing essential oils: new options for mosquito control.

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Werdin González, Jorge Omar; Jesser, Emiliano Nicolás; Yeguerman, Cristhian Alan; Ferrero, Adriana Alicia; Fernández Band, Beatriz

2017-07-01

Mosquitoes (Diptera: Culicidae) are vectors of important parasites and pathogens causing death, poverty and social disability worldwide. The overuse of synthetic insecticides to control mosquito vectors lead to resistance, adverse environmental effects and high operational costs. Therefore, the development of eco-friendly control tools is an important public health challenge. In this study, two different essential oils (EO) (geranium, Geranium maculatum, and bergamot, Citrus bergamia) loaded polymeric nanoparticle (PN) were elaborated using polyethylene glycol (PEG) and chitosan (Qx) as the polymeric matrix/coating. In addition, the mosquito larvicidal acute and residual activity of the PN was evaluated on Culex pipiens pipiens. The physicochemical characterization of PN revealed that PEG-PN had sizes nanoparticles containing essential oil are a promising source of eco-friendly mosquito larvicidal products.

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

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Magdalena Laurito

Full Text Available Culex bidens and C. interfor, implicated in arbovirus transmission in Argentina, are sister species, only distinguishable by feature of the male genitalia; however, intermediate specimens of the species in sympatry have been found. Fourth-instar larvae and females of both species share apomorphic features, and this lack of clear distinction creates problems for specific identification. Geometric morphometric traits of these life stages also do not distinguish the species. The aim of the present study was to assess the taxonomic status of C. bidens and C. interfor using two mitochondrial genes and to determine the degree of their reproductive isolation using microsatellite loci. Sequences of the ND4 and COI genes were concatenated in a matrix of 993 nucleotides and used for phylogenetic and distance analyses. Bayesian and maximum parsimony inferences showed a well resolved and supported topology, enclosing sequences of individuals of C. bidens (0.83 BPP, 73 BSV and C. interfor (0.98 BPP, 97 BSV in a strong sister relationship. The mean K2P distance within C. bidens and C. interfor was 0.3% and 0.2%, respectively, and the interspecific variation was 2.3%. Bayesian clustering also showed two distinct mitochondrial lineages. All sequenced mosquitoes were successfully identified in accordance with the best close match algorithm. The low genetic distance values obtained indicate that the species diverged quite recently. Most morphologically intermediate specimens of C. bidens from Córdoba were heterozygous for the microsatellite locus GT51; the significant heterozygote excess observed suggests incomplete reproductive isolation. However, C. bidens and C. interfor should be considered good species: the ventral arm of the phallosome of the male genitalia and the ND4 and COI sequences are diagnostic characters.

Combining hydrology and mosquito population models to identify the drivers of Rift Valley fever emergence in semi-arid regions of West Africa.

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Soti, Valérie; Tran, Annelise; Degenne, Pascal; Chevalier, Véronique; Lo Seen, Danny; Thiongane, Yaya; Diallo, Mawlouth; Guégan, Jean-François; Fontenille, Didier

2012-01-01

Rift Valley fever (RVF) is a vector-borne viral zoonosis of increasing global importance. RVF virus (RVFV) is transmitted either through exposure to infected animals or through bites from different species of infected mosquitoes, mainly of Aedes and Culex genera. These mosquitoes are very sensitive to environmental conditions, which may determine their presence, biology, and abundance. In East Africa, RVF outbreaks are known to be closely associated with heavy rainfall events, unlike in the semi-arid regions of West Africa where the drivers of RVF emergence remain poorly understood. The assumed importance of temporary ponds and rainfall temporal distribution therefore needs to be investigated. A hydrological model is combined with a mosquito population model to predict the abundance of the two main mosquito species (Aedes vexans and Culex poicilipes) involved in RVFV transmission in Senegal. The study area is an agropastoral zone located in the Ferlo Valley, characterized by a dense network of temporary water ponds which constitute mosquito breeding sites. The hydrological model uses daily rainfall as input to simulate variations of pond surface areas. The mosquito population model is mechanistic, considers both aquatic and adult stages and is driven by pond dynamics. Once validated using hydrological and entomological field data, the model was used to simulate the abundance dynamics of the two mosquito species over a 43-year period (1961-2003). We analysed the predicted dynamics of mosquito populations with regards to the years of main outbreaks. The results showed that the main RVF outbreaks occurred during years with simultaneous high abundances of both species. Our study provides for the first time a mechanistic insight on RVFV transmission in West Africa. It highlights the complementary roles of Aedes vexans and Culex poicilipes mosquitoes in virus transmission, and recommends the identification of rainfall patterns favourable for RVFV amplification.

Combining hydrology and mosquito population models to identify the drivers of Rift Valley fever emergence in semi-arid regions of West Africa.

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Valérie Soti

Full Text Available BACKGROUND: Rift Valley fever (RVF is a vector-borne viral zoonosis of increasing global importance. RVF virus (RVFV is transmitted either through exposure to infected animals or through bites from different species of infected mosquitoes, mainly of Aedes and Culex genera. These mosquitoes are very sensitive to environmental conditions, which may determine their presence, biology, and abundance. In East Africa, RVF outbreaks are known to be closely associated with heavy rainfall events, unlike in the semi-arid regions of West Africa where the drivers of RVF emergence remain poorly understood. The assumed importance of temporary ponds and rainfall temporal distribution therefore needs to be investigated. METHODOLOGY/PRINCIPAL FINDINGS: A hydrological model is combined with a mosquito population model to predict the abundance of the two main mosquito species (Aedes vexans and Culex poicilipes involved in RVFV transmission in Senegal. The study area is an agropastoral zone located in the Ferlo Valley, characterized by a dense network of temporary water ponds which constitute mosquito breeding sites. The hydrological model uses daily rainfall as input to simulate variations of pond surface areas. The mosquito population model is mechanistic, considers both aquatic and adult stages and is driven by pond dynamics. Once validated using hydrological and entomological field data, the model was used to simulate the abundance dynamics of the two mosquito species over a 43-year period (1961-2003. We analysed the predicted dynamics of mosquito populations with regards to the years of main outbreaks. The results showed that the main RVF outbreaks occurred during years with simultaneous high abundances of both species. CONCLUSION/SIGNIFICANCE: Our study provides for the first time a mechanistic insight on RVFV transmission in West Africa. It highlights the complementary roles of Aedes vexans and Culex poicilipes mosquitoes in virus transmission, and recommends

Larvicidal activity and possible mode of action of four flavonoids and two fatty acids identified in Millettia pinnata seed toward three mosquito species.

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Perumalsamy, Haribalan; Jang, Myung Jin; Kim, Jun-Ran; Kadarkarai, Murugan; Ahn, Young-Joon

2015-04-19

Aedes aegypti and Aedes albopictus and Culex pipiens pallens mosquitoes transmit dengue fever and West Nile virus diseases, respectively. This study was conducted to determine the toxicity and mechanism of action of four flavonoids and two fatty acids from Millettia pinnata (Fabaceae) seed as well as six pure fatty acids and four fatty acid esters toward third instar larvae from insecticide-susceptible C. pipiens pallens and A. aegypti as well as wild A. albopictus. Efficacy of 12 experimental liquid formulations containing M. pinnata seed methanol extract and hydrodistillate (0.5-10.0% liquids) was also assessed. The contact toxicities of all compounds and 12 formulations were compared with those of two larvicides, temephos and fenthion and the commercial temephos 200 g/L emulsifiable concentrate (EC). The possible mode of larvicidal action of the constituents was elucidated using biochemical methods. Larval mortality and cAMP level were analyzed by the Bonferroni multiple-comparison method. Potent toxicity was produced by karanjin, oleic acid, karanjachromene, linoleic acid, linolenic acid, pongamol, pongarotene, and elaidic acid toward C. pipiens pallens larvae (24 h LC50, 14.61-28.22 mg/L) and A. aegypti larvae (16.13-37.61 mg/L). Against wild A. albopictus larvae, oleic acid (LC50, 18.79 mg/L) and karanjin (35.26 mg/L) exhibited potent toxicity. All constituents were less toxic than either temephos or fenthion. Structure-activity relationship indicates that the degree of saturation, the side chain length, and the geometric isomerism of fatty acids appear to play a role in determining the fatty acid toxicity. Acetylcholinesterase (AChE) is the main site of action of the flavonoids, oleic acid, and palmitic acid. The mechanism of larvicidal action of elaidic acid, arachidic acid, and behenic acid might be due to interference with the octopaminergic system. Linoleic acid and linolenic acid might act on both AChE and octopaminergic receptor. M. pinnata seed

Mosquito bite anaphylaxis: immunotherapy with whole body extracts.

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McCormack, D R; Salata, K F; Hershey, J N; Carpenter, G B; Engler, R J

1995-01-01

Adverse reactions to mosquito bites have been recognized for some time. These usually consist of large local swellings and redness, generalized urticaria, angioedema and less easily definable responses such as nausea, dizziness, headaches, and lethargy. We report two patients who experienced systemic anaphylaxis from mosquito bites. Both were skin tested and given immunotherapy using whole body mosquito extracts. Skin testing using whole body mosquito extracts was positive to Aedes aegypti at 1/1,000 weight/volume (wt/vol) in one patient and to Aedes aegypti at 1/100,000 wt/vol, and Culex pipiens at 1/10,000 wt/vol in the other. Skin testing of ten volunteers without a history of adverse reactions to mosquito bites was negative. Immunotherapy using these extracts resulted in resolution of adverse reactions to mosquito bites in one patient and a decrease in reactions in the other. Immunotherapy with whole body mosquito extracts is a viable treatment option that can play a role in patients with mosquito bite-induced anaphylaxis. It may also result in severe side effects and one must determine the benefit versus risks for each individual patient.

Ecological differentiation of members of the Culex pipiens complex, potential vectors of West Nile virus and Rift Valley fever virus in Algeria.

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Amara Korba, Raouf; Alayat, Moufida Saoucen; Bouiba, Lazhari; Boudrissa, Abdelkarim; Bouslama, Zihad; Boukraa, Slimane; Francis, Frederic; Failloux, Anna-Bella; Boubidi, Saïd Chaouki

2016-08-17

We investigated the ecological differentiation of two members of the Culex pipiens complex, Cx. p. pipiens form pipiens and Cx. p. pipiens form molestus in three sites, El-Kala, M'Sila and Tinerkouk in Algeria. These two forms are the most widespread mosquito vectors in temperate regions exhibiting important behavioural and physiological differences. Nevertheless, this group of potential vectors has been poorly studied, particularly in North Africa. Ten larval populations of Cx. p. pipiens were sampled from various above- and underground habitats in three zones representing the three bioclimatic regions in Algeria. The reproduction characteristics were also investigated in the laboratory to define the rates of autogeny and stenogamy. Identification of Cx. p. pipiens members present in Algeria was achieved using a molecular analysis with the microsatellite CQ11 locus. We detected larvae of Cx. p. pipiens in all areas suggesting that the species is a ubiquitous mosquito well adapted to various environments. To our knowledge, this study provides the first molecular evidence of the presence of the Cx. p. pipiens form molestus and hybrids (molestus/pipiens) in Algeria with a high proportion of molestus form (48.3 %) in comparison with hybrids (36.8 %) and pipiens form (14.9 %). Some unexpected correlations between the proportion of forms pipiens, molestus and hybrids, and mosquito biological characteristics were observed suggesting some epigenetic effects controlling Cx. p. pipiens mating and reproduction. Consequences for pathogen transmission are discussed.

Attractiveness of botanical infusions to ovipositing Culex quinquefasciatus, Cx. nigripalpus, and Cx. erraticus in San Antonio, Texas.

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McPhatter, Lee P; Debboun, Mustapha

2009-12-01

Field experiments were conducted on the Fort Sam Houston Military Reservation, San Antonio, TX, in fall 2008 to observe the attractiveness of selected botanical infusions to ovipositing female mosquitoes. The following infusions were tested in Centers for Disease Control and Prevention gravid traps: Bermuda grass (Cynodon dactylon), oak leaf (Quercus virginiana), acacia leaf (Acacia schaffneri), rabbit chow (alfalfa pellets), and algae (Spirogyra sp.). Four (Bermuda, acacia, oak, and algae) of the 5 infusions were effective in collecting Culex quinquefasciatus, Cx. nigripalpus, and Cx. erraticus. Of the 4 infusions, Bermuda collected the greatest number of the mosquitoes sampled. Female Aedes albopictus mosquitoes were collected in moderate numbers during this study.

Susceptibility of Adult Mosquitoes to Insecticides in Aqueous Sucrose Baits

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2011-06-01

Lee, and A.H. Azahari. 2005. Adult and larval insecticide susceptibility status of Culex quinquefasciatus (Say) mosquitoes in Kuala Lumpur Malaysia ...Trop. Biomed. 22: 63-68. Nayar, J.K. and D.M. Sauerman, Jr. 1971. The effects of diet on life-span, fecundity and flight potential of Aedes

Oviposition Deterrent and Larvicidal and Pupaecidal Activity of Seven Essential Oils and their Major Components against Culex quinquefasciatus Say (Diptera: Culicidae): Synergism–antagonism Effects

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Andrade-Ochoa, Sergio; Sánchez-Aldana, Daniela; Chacón-Vargas, Karla Fabiola; Rivera-Chavira, Blanca E.; Camacho, Alejandro D.; Nogueda-Torres, Benjamín

2018-01-01

The larvicidal activity of essential oils cinnamon (Cinnamomum verum J. Presl), Mexican lime (Citrus aurantifolia Swingle) cumin (Cuminum cyminum Linnaeus), clove (Syzygium aromaticum (L.) Merr. & L.M.Perry), laurel (Laurus nobilis Linnaeus), Mexican oregano (Lippia berlandieri Schauer) and anise (Pimpinella anisum Linnaeus)) and their major components are tested against larvae and pupae of Culex quinquefasciatus Say. Third instar larvae and pupae are used for determination of lethality and mortality. Essential oils with more than 90% mortality after a 30-min treatment are evaluated at different time intervals. Of the essential oils tested, anise and Mexican oregano are effective against larvae, with a median lethal concentration (LC50) of 4.7 and 6.5 µg/mL, respectively. Anise essential oil and t-anethole are effective against pupae, with LC50 values of 102 and 48.7 µg/mL, respectively. Oregano essential oil and carvacrol also have relevant activities. A kinetic analysis of the larvicidal activity, the oviposition deterrent effect and assays of the effects of the binary mixtures of chemical components are undertaken. Results show that anethole has synergistic effects with other constituents. This same effect is observed for carvacrol and thymol. Limonene shows antagonistic effect with β-pinene. The high larvicidal and pupaecidal activities of essential oils and its components demonstrate that they can be potential substitutes for chemical compounds used in mosquitoes control programs. PMID:29443951

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

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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.

Patterns of phenoloxidase activity in insecticide resistant and susceptible mosquitoes differ between laboratory-selected and wild-caught individuals

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Cornet, St?phane; Gandon, Sylvain; Rivero, Ana

2013-01-01

Background Insecticide resistance has the potential to alter vector immune competence and consequently affect the transmission of diseases. Methods Using both laboratory isogenic strains and field-caught Culex pipiens mosquitoes, we investigated the effects of insecticide resistance on an important component of the mosquito immune system: the phenoloxidase (PO) activity. As infection risk varies dramatically with the age and sex of mosquitoes, allocation to PO immunity was quantified across d...

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

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

Infection and transmission of Rift Valley fever viruses lacking the NSs and/or NSm genes in mosquitoes: potential role for NSm in mosquito infection.

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Mary B Crabtree

Full Text Available BACKGROUND: Rift Valley fever virus is an arthropod-borne human and animal pathogen responsible for large outbreaks of acute and febrile illness throughout Africa and the Arabian Peninsula. Reverse genetics technology has been used to develop deletion mutants of the virus that lack the NSs and/or NSm virulence genes and have been shown to be stable, immunogenic and protective against Rift Valley fever virus infection in animals. We assessed the potential for these deletion mutant viruses to infect and be transmitted by Aedes mosquitoes, which are the principal vectors for maintenance of the virus in nature and emergence of virus initiating disease outbreaks, and by Culex mosquitoes which are important amplification vectors. METHODOLOGY AND PRINCIPAL FINDINGS: Aedes aegypti and Culex quinquefasciatus mosquitoes were fed bloodmeals containing the deletion mutant viruses. Two weeks post-exposure mosquitoes were assayed for infection, dissemination, and transmission. In Ae. aegypti, infection and transmission rates of the NSs deletion virus were similar to wild type virus while dissemination rates were significantly reduced. Infection and dissemination rates for the NSm deletion virus were lower compared to wild type. Virus lacking both NSs and NSm failed to infect Ae. aegypti. In Cx. quinquefasciatus, infection rates for viruses lacking NSm or both NSs and NSm were lower than for wild type virus. CONCLUSIONS/SIGNIFICANCE: In both species, deletion of NSm or both NSs and NSm reduced the infection and transmission potential of the virus. Deletion of both NSs and NSm resulted in the highest level of attenuation of virus replication. Deletion of NSm alone was sufficient to nearly abolish infection in Aedes aegypti mosquitoes, indicating an important role for this protein. The double deleted viruses represent an ideal vaccine profile in terms of environmental containment due to lack of ability to efficiently infect and be transmitted by mosquitoes.

Infection and transmission of Rift Valley fever viruses lacking the NSs and/or NSm genes in mosquitoes: potential role for NSm in mosquito infection.

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Crabtree, Mary B; Kent Crockett, Rebekah J; Bird, Brian H; Nichol, Stuart T; Erickson, Bobbie Rae; Biggerstaff, Brad J; Horiuchi, Kalanthe; Miller, Barry R

2012-01-01

Rift Valley fever virus is an arthropod-borne human and animal pathogen responsible for large outbreaks of acute and febrile illness throughout Africa and the Arabian Peninsula. Reverse genetics technology has been used to develop deletion mutants of the virus that lack the NSs and/or NSm virulence genes and have been shown to be stable, immunogenic and protective against Rift Valley fever virus infection in animals. We assessed the potential for these deletion mutant viruses to infect and be transmitted by Aedes mosquitoes, which are the principal vectors for maintenance of the virus in nature and emergence of virus initiating disease outbreaks, and by Culex mosquitoes which are important amplification vectors. Aedes aegypti and Culex quinquefasciatus mosquitoes were fed bloodmeals containing the deletion mutant viruses. Two weeks post-exposure mosquitoes were assayed for infection, dissemination, and transmission. In Ae. aegypti, infection and transmission rates of the NSs deletion virus were similar to wild type virus while dissemination rates were significantly reduced. Infection and dissemination rates for the NSm deletion virus were lower compared to wild type. Virus lacking both NSs and NSm failed to infect Ae. aegypti. In Cx. quinquefasciatus, infection rates for viruses lacking NSm or both NSs and NSm were lower than for wild type virus. In both species, deletion of NSm or both NSs and NSm reduced the infection and transmission potential of the virus. Deletion of both NSs and NSm resulted in the highest level of attenuation of virus replication. Deletion of NSm alone was sufficient to nearly abolish infection in Aedes aegypti mosquitoes, indicating an important role for this protein. The double deleted viruses represent an ideal vaccine profile in terms of environmental containment due to lack of ability to efficiently infect and be transmitted by mosquitoes.

Host feeding pattern of Japanese encephalitis virus vector mosquitoes (Diptera: Culicidae) from Kuttanadu, Kerala, India.

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Philip Samuel, P; Arunachalam, N; Hiriyan, J; Tyagi, B K

2008-09-01

Identification of blood meals of vector mosquitoes is an important tool in the epidemiological investigations of vector-borne diseases. The blood meals of three mosquito species involved in the transmission of Japanese encephalitis virus (JEV) from the Kuttanadu area, Kerala, were determined using the agarose gel diffusion technique. A total of 4959 blood smears belonging to Culex (Culex) tritaeniorhynchus Giles (3273), Cx. (Culex) gelidus Theobald (64), Mansonia (Mnd.) indiana Edwards (735) ,and Ma. (Mnd.) uniformis (Theobald) (887) were tested. Cx. tritaeniorhynchus had predominantly fed on bovids (46.4%), and a good proportion (29%) had fed on more than one host. Cx. tritaeniorhynchus was highly zoophagic, and human feeding accounted for only 1.5% of those individuals successfully tested. Cx. gelidus showed bovid feeding at 36% and pig feeding at 12.5%. The test results showed 42.3% Ma. indiana and 12.2% Ma. uniformis had fed on humans. Multiple feeding was observed in Ma. indiana and Ma. uniformis, and most of the double feedings were from bovids and ovids (7.9 and 20.1%, respectively). Pig feeding accounted for 4.8% of the feedings by Cx. tritaeniorhynchus, 5.3% of Ma. indiana, and 6.4% of Ma. uniformis. This study is significant because of the role played by these mosquitoes in the transmission of JEV in the Kuttanadu area of Kerala, India.

Wolbachia Effects on Rift Valley Virus Infection in Culex tarsalis Mosquitoes

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2017-04-25

Wolbachia density in mosquitoes. 109" 110" Materials and Methods 111" Ethics statement 112" TR-17-113 Mosquitoes were maintained on commercially available...fever virus. 379" Vet Med Today. 2009; 883–893. 380" 29. Wilson M. Rift Valley fever virus ecology and the epidemiology of disease emergence. 381

Vector Competence of American Mosquitoes for Three Strains of Zika Virus.

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James Weger-Lucarelli

2016-10-01

Full Text Available In 2015, Zika virus (ZIKV; Flaviviridae; Flavivirus emerged in the Americas, causing millions of infections in dozens of countries. The rapid spread of the virus and the association with disease outcomes such as Guillain-Barré syndrome and microcephaly make understanding transmission dynamics essential. Currently, there are no reports of vector competence (VC of American mosquitoes for ZIKV isolates from the Americas. Further, it is not clear whether ZIKV strains from other genetic lineages can be transmitted by American Aedes aegypti populations, and whether the scope of the current epidemic is in part facilitated by viral factors such as enhanced replicative fitness or increased vector competence. Therefore, we characterized replication of three ZIKV strains, one from each of the three phylogenetic clades in several cell lines and assessed their abilities to be transmitted by Ae. aegypti mosquitoes. Additionally, laboratory colonies of different Culex spp. were infected with an American outbreak strain of ZIKV to assess VC. Replication rates were variable and depended on virus strain, cell line and MOI. African strains used in this study outcompeted the American strain in vitro in both mammalian and mosquito cell culture. West and East African strains of ZIKV tested here were more efficiently transmitted by Ae. aegypti from Mexico than was the currently circulating American strain of the Asian lineage. Long-established laboratory colonies of Culex mosquitoes were not efficient ZIKV vectors. These data demonstrate the capacity for additional ZIKV strains to infect and replicate in American Aedes mosquitoes and suggest that neither enhanced virus replicative fitness nor virus adaptation to local vector mosquitoes seems likely to explain the extent and intensity of ZIKV transmission in the Americas.

Transgenerational interactions between pesticide exposure and warming in a vector mosquito

DEFF Research Database (Denmark)

Tran, Tam T.; Janssens, Lizanne; Dinh, Khuong Van

2018-01-01

of single and combined exposure to warming (4°C increase) and the pesticide chlorpyrifos on life history traits of the vector mosquito Culex pipiens. Parental exposure to a single stressor, either warming or the pesticide, had negative effects on the offspring: both parental exposure to warming...

Ecologia de mosquitos (Diptera, Culicidae em criadouros naturais e artificiais de área rural do norte do Parana, Brasil: II. Coletas com isca humana Ecology of mosquitoes (Diptera, Culicidae in natural and artificial breeding sites of the rural area in north Paraná, Brazil: II. Capture of human bait

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José Lopes

1996-01-01

Full Text Available With then purpose of knowing the species of mosquitos that colonize an anthropogenic area in the North of Paraná, Brazil. 1496 specimens were captured by the humam bait method, accountig 23 species among them the following were predominam: Anopheles strodei Root, 1926; An. evansae Brethes, 1926; An. galvaoi Causey, Deane & Deane, 1943; An. albitarsis Lynch Arribalzaga, 1878; Coquillettidea juxtamansonia Chagas, 1907; Co. venezuelensis Theobaldi, 1912; Culex (Melanoconion sp. e Aedes fluviatilis (Lutz, 1904 and showed shong anthopophilia and a high degree of adaptation to humam environment. On the cantray, the species that showed lilth adaptation to such ambients or to the geoclimatic conditions of the region were: Anopheles triannulatus (Neiva & Pinto, 1922; An. parvus (Chagas, 1907; An. lutzii Cruzi, 1901, Culex amazonensis (Lutz, 1905; Cx. chidesteri; Psorophora confinnis (Linch Arribalzaga, 1891; Ps. discrucians (Walker, 1856; Ps. cingulata (Fabricius, 1805 e Aedes scapularis. Although Anopheles argyritarsis Robineau-Desvoidy, 1827; Culex coronator Dyar & Knab, 1906; Cx. mollis Dyar & Knab, 1906 and Cx. quinquefasciatus Say, 1823, were captured in little numbers, it is knowntht they an mosquito of human surroundings. These mosquitos showed a plak of feeding activity directly related to sunset bat did not have a bimodal behaviour. Anophelinae were in general more active in spring while Culex Linnaeus, 1758; Coquillettidia Dyar, 1905; Aedes Meigen, 1818; Mansonia Blanchard, 1901 e Psorophora Robineau-Desvoidy, 1827 were more active in summer.

Mosquito fauna and arbovirus surveillance in a coastal Mississippi community after Hurricane Katrina.

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Foppa, Ivo M; Evans, Christopher L; Wozniak, Arthur; Wills, William

2007-06-01

Hurricane Katrina caused massive destruction and flooding along the Gulf Coast in August 2005. We collected mosquitoes and tested them for arboviral infection in a severely hurricane-damaged community to determine species composition and to assess the risk of a mosquito-borne epidemic disease in that community about 6 wk after the landfall of Hurricane Katrina. Light-trap collections yielded 8,215 mosquitoes representing 19 species, while limited gravid-trap collections were not productive. The most abundant mosquito species was Culex nigripalpus, which constituted 73.6% of all specimens. No arboviruses were detected in any of the mosquitoes collected in this survey, which did not support the assertion that human risk for arboviral infection was increased in the coastal community 6 wk after the hurricane.

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

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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.

Slow release formulations of Bacillus thuringiensis israelensis (AM 65-52 and spinosyns: effectiveness against the West Nile vector Culex pipiens in Saudi Arabia

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Alaa Sulaiman Alsobhi

2016-07-01

Full Text Available Objective: To investigate the effectiveness of slow release formulations of Bacillus thuringiensis israelensis (AM 65-52 (B. thuringiensis israelensis and spinosyns against the West Nile vector Culex pipiens (Cx. pipiens in Saudi Arabia. Methods: We tested slow release insecticide formulations of Natular DT, Tap 60 and VectoBac granule against II instars of Cx. pipiens larvae in 50 L laboratory arenas. Results: Slow release formulations of B. thuringiensis israelensis and spinosyns gave continuous control against Cx. pipiens for several weeks. Natular DT was more effective over Tap 60 and VectoBac granule of about 1.3 and 5.8 times, respectively. Variations in the durations of effective control among the tested slow release formulations may reflect differences in their active ingredients and the mode of action. Conclusions: Our results highlighted the effectiveness of B. thuringiensis israelensis and spinosyns against an important West Nile vector, providing baseline data to develop ecofriendly mosquito control programs in Saudi Arabia.

Adulticidal activity of Pithecellobium dulce (Roxb. Benth. against Culex quinquefasciatus (Say

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Govindarajan M

2012-04-01

Full Text Available Objective: To determine the adulticidal efficacy of different solvent leaf and seed extracts of Pithecellobium dulce (P. dulce against Culex quinquefasciatus (Cx. quinquefasciatus. Methods: Sucrose-fed and blood starved mosquitoes were released into the tube, and the mortality effects of the extracts were observed every 10 min for 3 h exposure period. At the end of 1, 2, and 3 h exposure periods, the mosquitoes were placed in the holding tube. Cotton pads soaked in 10% sugar solution with vitamin B complex were placed in the tube during the holding period of 24 h. Mortality of the mosquitoes was recorded after 24 h. Results: Among five solvent extracts tested, the maximum efficacy was observed in the methanol extract of leaves of P. dulce. The LC50 and LC 90 values of P. dulce leaves and seeds against Cx. quinquefasciatus were 234.97, 309.24 ppm and 464.86, 570.80 ppm, respectively. No mortality was observed in controls. The Chi-square values were significant at P<0.05 level. Conclusions: From the results it can be concluded that the crude extract of P. dulce has excellent potential for controlling filariasis vector mosquito, Cx. quinquefasciatus. This is the first report on the mosquito adulticidal activity of the reported P. dulce plant.

Ecology of Culiseta Melanura and Other Mosquitoes (Diptera: Culicidae) from Walton County, FL, During Winter Period 2013-2014.

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Burkett-Cadena, Nathan D; Bingham, Andrea M; Hunt, Brenda; Morse, Gary; Unnasch, Thomas R

2015-09-01

Winter ecology of putative vectors of eastern equine encephalomyelitis virus (EEEV) in northern Florida was investigated at field locations with evidence of historic EEEV winter transmission. Light traps and resting shelters were used to sample the mosquito community in the vicinity of eight sentinel flocks throughout the winter period (November-April) of 2013 and 2014 in Walton County, FL. Overall mosquito activity was relatively low, although mosquitoes were captured during each week of the study period. Mosquito activity was linked to morning temperature, and females were captured when ambient morning temperatures were quite low (1-5°C). Anopheles crucians Wiedemann, Culex erraticus (Dyar and Knab), Culex territans Walker, and Culiseta melanura (Coquillett) were the most commonly collected mosquito species (of 20 total species). Analysis of blood-engorged mosquitoes revealed a number of mosquito species feeding upon chickens, other birds, amphibians, and domestic and wild mammals. Cs. melanura fed primarily upon chickens and songbirds (Passeriformes), suggesting that this mosquito species is the likely winter vector of EEEV to sentinel chickens in northern Florida. Both resident and nonresident songbird species were fed upon, constituting 63.9 and 36.1% of total songbird meals, respectively. Our results suggest important roles for Cs. melanura and songbird hosts for the winter transmission of EEEV in northern Florida. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

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Paperna I.

2004-06-01

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

Field evaluation of spatial repellency of metofluthrin impregnated plastic strips against mosquitoes in Hai Phong city, Vietnam.

OpenAIRE

Kawada, Hitoshi; Nguyen Thi Yen; Nguen Thuy Hoa; Truong Minh Sang; Nguyen Van Dan; Takagi, Masahiro

2005-01-01

Spatial repellency of metofluthrin-impregnated polyethylene plastic strips against mosquitoes, Aedes aegypti and Culex quinquefasciatus, were studied in a residential area in Hai Phong city, Vietnam. Thirty houses were selected as trial sites; half of these were assigned as untreated control and the other half were assigned for treatment.Primarily, irrespective of the room size, one room was treated with one strip. The dominant species in the trial sites were Culex quinquefasciatus and Aedes ...

Transgenerational interactions between a pesticide and warming in a vector mosquito

DEFF Research Database (Denmark)

Tran, T.; Dinh, Khuong Van; Stoks, R.

may change in a polluted environment. We set up a full-factorial transgenerational experiment where Culex pipiens vector mosquitoes were reared at two temperatures (20°C vs 24°C) and, when they reached the final larval stage, exposed to one of two chlorpyrifos treatments (absent vs present). We...

Role of wastewater irrigation in mosquito breeding in south Punjab, Pakistan

DEFF Research Database (Denmark)

Mukhtar, Muhammad; Herrel, Nathaly; Amerasinghe, Felix P

2003-01-01

and the wastewater disposal system. Overall, 17.3% of the samples were positive for Anopheles, 12.0% for Culex and 15.0% for Aedes. Four anopheline species, viz, Anopheles stephensi (84.3% of total anophelines), An. subpictus (11.8%), An. culicifacies (2.0%) and An. pulcherrimus (0.2%) were present, as were two...... species of Culex, viz, Cx. quinquefasciatus (66.5% of culicines) and Cx. tritaeniorhynchus (20.1%). Aedes were not identified to species level. The occurrence of different species was linked to particular habitats and habitat characteristics such as physical water condition, chemical water quality...... and the presence of fauna and flora. Anophelines and Aedes mosquitos were mainly collected during the month of July, while Culex were collected in September. The prevalence of established vectors of human diseases such as An. stephensi (malaria), Cx. tritaeniorhynchus (West Nile fever, Japanese encephalitis...

Chemical composition, toxicity and non-target effects of Pinus kesiya essential oil: An eco-friendly and novel larvicide against malaria, dengue and lymphatic filariasis mosquito vectors.

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Govindarajan, Marimuthu; Rajeswary, Mohan; Benelli, Giovanni

2016-07-01

Mosquitoes (Diptera: Culicidae) are vectors of important parasites and pathogens causing death, poverty and social disability worldwide, with special reference to tropical and subtropical countries. The overuse of synthetic insecticides to control mosquito vectors lead to resistance, adverse environmental effects and high operational costs. Therefore, the development of eco-friendly control tools is an important public health challenge. In this study, the mosquito larvicidal activity of Pinus kesiya leaf essential oil (EO) was evaluated against the malaria vector Anopheles stephensi, the dengue vector Aedes aegypti and the lymphatic filariasis vector Culex quinquefasciatus. The chemical composition of the EO was analyzed by gas chromatography-mass spectroscopy. GC-MS revealed that the P. kesiya EO contained 18 compounds. Major constituents were α-pinene, β-pinene, myrcene and germacrene D. In acute toxicity assays, the EO showed significant toxicity against early third-stage larvae of An. stephensi, Ae. aegypti and Cx. quinquefasciatus, with LC50 values of 52, 57, and 62µg/ml, respectively. Notably, the EO was safer towards several aquatic non-target organisms Anisops bouvieri, Diplonychus indicus and Gambusia affinis, with LC50 values ranging from 4135 to 8390µg/ml. Overall, this research adds basic knowledge to develop newer and safer natural larvicides from Pinaceae plants against malaria, dengue and filariasis mosquito vectors. Copyright © 2016 Elsevier Inc. All rights reserved.

Mosquito (Diptera: Culicidae) Habitat Surveillance by Android Mobile Devices in Guangzhou, China.

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Wu, Tai-Ping; Tian, Jun-Hua; Xue, Rui-De; Fang, Yi-Liang; Zheng, Ai-Hua

2016-12-17

In 2014, Guangzhou City, South China, suffered from its worst outbreak of dengue fever in decades. Larval mosquito habitat surveillance was carried out by using android mobile devices in four study sites in May 2015. The habitats with larval mosquitoes were recorded as photo waypoints in OruxMaps or in videos. The total number of potential mosquito habitats was 342, of which 166 (49%) were found to have mosquito larvae or pupae. Small containers were the most abundant potential habitats, accounting for 26% of the total number. More mosquito larvae and pupae, were found in small containers than in other objects holding water, for example, potted or hydroponic plants ( p Android mobile devices are a convenient and useful tool for surveillance of mosquito habitats, and the enhancement of source reduction may benefit the prevention and control of dengue vector mosquitoes.

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

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Tri Ramadhani

2012-11-01

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

Differential effect of human ivermectin treatment on blood feeding Anopheles gambiae and Culex quinquefasciatus

DEFF Research Database (Denmark)

Derua, Yahya A.; Kisinza, William N.; Simonsen, Paul Erik

2015-01-01

BACKGROUND: Widespread and large scale use of ivermectin in humans and domestic animals can have unexpected effects on non-target organisms. As a search for a possible explanation for an observed longitudinal decline in density of anopheline vector mosquitoes, but not in Culex quinquefasciatus...... to receive either ivermectin or placebo. Twenty four hours after treatment, one volunteer from each group was concurrently exposed to 50 laboratory reared An. gambiae on one arm and 50 laboratory reared Cx. quinquefasciatus on the other arm for 15-30 minutes. Engorged mosquitoes were maintained on 10...

Mosquito (Diptera: Culicidae) fauna in an area endemic for West Nile virus

Czech Academy of Sciences Publication Activity Database

Šebesta, Oldřich; Halouzka, Jiří; Hubálek, Zdeněk; Juřicová, Zina; Rudolf, Ivo; Šikutová, Silvie; Svobodová, Petra; Reiter, P.

2010-01-01

Roč. 35, č. 1 (2010), s. 156-162 ISSN 1081-1710 EU Projects: European Commission(XE) 10284 - EDEN Institutional research plan: CEZ:AV0Z60930519 Keywords : mosquito es * Anopheles * Aedes * Culex * climate * ecology Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology Impact factor: 1.256, year: 2010

Development of Hepatozoon caimani (Carini, 1909 Pessôa, De Biasi & De Souza, 1972 in the Caiman Caiman c. crocodilus, the frog Rana catesbeiana and the mosquito Culex fatigans

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Lainson Ralph

2003-01-01

Full Text Available The sporogony of Hepatozoon caimani has been studied, by light microscopy, in the mosquito Culex fatigans fed on specimens of the caiman Caiman c. crocodilus showing gametocytes in their peripheral blood. Sporonts iniciate development in the space between the epithelium of the insect gut and the elastic membrane covering the haemocoele surface of the stomach. Sporulating oocysts are clustered on the gut, still invested by the gut surface membrane. Fully mature oocysts were first seen 21 days after the blood-meal. No sporogonic stages were found in some unidentified leeches fed on an infected caiman, up to 30 days following the blood-meal. When mosquitoes containing mature oocysts were fed to frogs (Leptodactylus fuscus and Rana catesbeiana, cysts containing cystozoites developed in the internal organs, principally the liver. Feeding these frogs to farm-bred caimans resulted in the appearance of gametocytes in their peripheral blood at some time between 59 and 79 days later, and the development of tissue cysts in the liver, spleen, lungs and kidneys. Transmission of the parasite was also obtained by feeding young caimans with infected mosquitoes and it is suggested that both methods occur in nature. The finding of similar cysts containing cystozoites in the semi-aquatic lizard Neusticurus bicarinatus, experimentally fed with infected C. fatigans, suggests that other secondary hosts may be involved.

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

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Emerson, Kevin J; Glaser, Robert L

2017-08-07

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

[Mosquitos of peri and extradomiciliary environments in the southern region of Brazil].

Science.gov (United States)

Teodoro, U; Guilherme, A L; Lozovei, A L; La Salvia Filho, V; Sampaio, A A; Spinosa, R P; Ferreira, M E; Barbosa, O C; de Lima, E M

1994-04-01

Mosquitoes were collected on Sonho Real farm, Querência do Norte county, Paraná State, Brazil, using human bait and Falcão traps between June 1989 and May 1990. The fauna composition, monthly density, hours of major density, human attraction and presence of mosquitoes in domestic animal shelters were investigated. 5,923 mosquitoes of the genera Aedes, Aedomyia, Anopheles, Coquillettidea, Culex, Mansonia, Psorophora, Sabethes and Uranotaenia were collected. 33 species of mosquitoes were identified and among them Aedes scapularis, Anopheles albitarsis, Aedomyia squamipennis, Coquillettidea lynchi, Mansonia titillans e Coquillettidea venezuelensis were predominant. All these species were captured mainly on human bait, except Aedomyia squamipennis that was captured in domestic animal shelters. With regard to all the mosquitoes captured (5,923), their major period of activity was between 18 and 19 hours and April was the month of greatest density.

Expectoration of Flaviviruses during sugar feeding by mosquitoes (Diptera: Culicidae).

Science.gov (United States)

van den Hurk, Andrew F; Johnson, Petrina H; Hall-Mendelin, Sonja; Northill, Judy A; Simmons, Russell J; Jansen, Cassie C; Frances, Stephen P; Smith, Greg A; Ritchie, Scott A

2007-09-01

Biological transmission of arboviruses to a vertebrate host occurs when virions are expelled along with saliva during blood feeding by a hematophagous arthropod. We undertook experiments to determine whether mosquitoes expectorate flaviviruses in their saliva while sugar feeding. Batches of Culex annulirostris Skuse and Culex gelidus Theobald (Diptera: Culicidae) were orally infected with Japanese encephalitis (family Flaviviridae, genus Flavivirus, JEV), Kunjin (family Flaviviridae, genus Flavivirus, KUNV; a subtype of West Nile virus), and Murray Valley encephalitis (family Flaviviridae, genus Flavivirus, MVEV) viruses. After a 7-d extrinsic incubation, these mosquitoes were offered sucrose meals via cotton pledgets, which were removed daily and processed for viral RNA by using real-time TaqMan reverse transcriptase-polymerase chain reaction (RT-PCR) assays. JEV, MVEV, and KUNV RNA was detected in all pledgets removed from batches of Cx. gelidus on days 7-14 postexposure. In contrast, detection rates were variable for Cx. annulirostris, with KUNV detected in 0.3 M sucrose pledgets on all days postexposure, and JEV and MVEV detected on 57 and 50% of days postexposure, respectively. Higher concentrations of sucrose in the pledget did not increase virus detection rates. When individual JEV-infected Cx. gelidus were exposed to the sucrose pledget, 73% of mosquitoes expectorated virus with titers that were detectable by TaqMan RT-PCR. These results clearly show that flaviviruses are expectorated by infected mosquitoes during the process of sugar feeding on artificial pledgets. Potential applications of the method for arboviral bioassays and field surveillance are discussed.

Detection, isolation, and genetic characterization of Rift Valley fever virus from Anopheles (Anopheles) coustani, Anopheles (Anopheles) squamosus, and Culex (Culex) antennatus of the Haute Matsiatra region, Madagascar.

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Ratovonjato, Jocelyn; Olive, Marie-Marie; Tantely, Luciano Michael; Andrianaivolambo, Lala; Tata, Etienne; Razainirina, Josette; Jeanmaire, Elisabeth; Reynes, Jean-Marc; Elissa, Nohal

2011-06-01

Following veterinary alerts of Rift Valley fever (RVF) in the districts of Fianarantsoa I and II in November 2008 and in the district of Ambalavao in April 2009, entomological and virological investigations were carried out to identify the mosquito species that could act as RVF virus (RVFV) vectors in the region. A total of 12,785 adult mosquitoes belonging to 5 genera and 21 species were collected. After identification, mosquitoes were pooled by species, sex, and female status (fed or unfed) and then stored at -80°C. Of 319 pools of unfed monospecific female mosquito tested by real-time RT-polymerase chain reaction, RVFV was detected in 1 pool of Anopheles coustani, 5 pools of An. squamosus, and 2 pools of Culex antennatus mosquitoes. The virus was isolated in mosquito cell lines from two of the five Real Time-RT-polymerase chain reaction (real time-RT-PCR) positive pools of An. squamosus mosquitoes. From the eight RVFV strains detected, partial S, M, and L genome segments sequences were obtained. The phylogenetic analysis of these sequences showed that the strains circulating in mosquitoes were genetically close to those that circulated in livestock and humans during RVF outbreaks in 2008 and 2009. This study, therefore, provides strong evidence that An. squamosus, An. coustani, and Cx. antennatus could play a role as vectors of the RVFV during the disease outbreaks in 2008-2009. Bioecological, genetic, and RVF transmission studies on these three mosquito species are needed to address this question and thus improve prevention and control of future RVF outbreaks in Madagascar, where these species are present.

Workbook on Identification of Aedes Aegypti Larvae.

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Pratt, Harry D.; And Others

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

Ecological characterization and molecular differentiation of Culex pipiens complex taxa and Culex torrentium in eastern Austria.

Science.gov (United States)

Zittra, Carina; Flechl, Eva; Kothmayer, Michael; Vitecek, Simon; Rossiter, Heidemarie; Zechmeister, Thomas; Fuehrer, Hans-Peter

2016-04-11

Culex pipiens complex taxa differ in behaviour, ecophysiology and epidemiologic importance. Despite their epidemiologic significance, information on genetic diversity, occurrence and seasonal and spatial distribution patterns of the Cx. pipiens complex is still insufficient. Assessment of seasonal and spatial distribution patterns of Culex pipiens forms and their congener Cx. torrentium is crucial for the understanding of their vector-pathogen dynamics. Female mosquitoes were trapped from April-October 2014 twice a month for a 24-h time period with BG-sentinel traps at 24 sampling sites in eastern Austria, using carbon dioxide as attractant. Ecological forms of Cx. pipiens s.l. and their hybrids were differentiated using the CQ11 locus, and Cx. pipiens forms and their congener Cx. torrentium using the ACE-2 gene. Differential exploitation of ecological niches by Cx. pipiens forms and Cx. torrentium was analysed using likelihood ratio tests. Possible effects of environmental parameters on these taxa were tested using PERMANOVA based on distance matrices and, if significant, were modelled in nMDS ordination space to estimate non-linear relationships. For this study, 1476 Culex spp. were sampled. Culex pipiens f. pipiens representing 87.33 % of the total catch was most abundant, followed by hybrids of both forms (5.62 %), Cx. torrentium (3.79 %) and Cx. pipiens f. molestus (3.25 %). Differences in proportional abundances were found between land cover classes. Ecological parameters affecting seasonal and spatial distribution of these taxa in eastern Austria are precipitation duration, air temperature, sunlight and the interaction term of precipitation amount and the Danube water level, which can be interpreted as a proxy for breeding habitat availability. The Cx. pipiens complex of eastern Austria comprises both ecologically different forms, the mainly ornithophilic form pipiens and the mainly mammalophilic and anthropophilic form molestus. Heterogeneous agricultural

Larval diet affects mosquito development and permissiveness to Plasmodium infection

OpenAIRE

Gendrin, MEM; Christophides; Linenberg, Inbar

2016-01-01

The larval stages of malaria vector mosquitoes develop in water pools, feeding mostly on microorganisms and environmental detritus. Richness in the nutrient supply to larvae influences the development and metabolism of larvae and adults. Here, we investigated the effects of larval diet on the development, microbiota content and permissiveness to Plasmodium of Anopheles coluzzii . We tested three fish diets often used to rear mosquitoes in the laboratory, including two pelleted diets, Dr. Clar...

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.

Darker eggs of mosquitoes resist more to dry conditions: Melanin enhances serosal cuticle contribution in egg resistance to desiccation in Aedes, Anopheles and Culex vectors.

Science.gov (United States)

Farnesi, Luana C; Vargas, Helena C M; Valle, Denise; Rezende, Gustavo L

2017-10-01

Mosquito vectors lay their white eggs in the aquatic milieu. During early embryogenesis water passes freely through the transparent eggshell, which at this moment is composed of exochorion and endochorion. Within two hours the endochorion darkens via melanization but even so eggs shrink and perish if removed from moisture. However, during mid-embryogenesis, cells of the extraembryonic serosa secrete the serosal cuticle, localized right below the endochorion, becoming the third and innermost eggshell layer. Serosal cuticle formation greatly reduces water flow and allows egg survival outside the water. The degree of egg resistance to desiccation (ERD) at late embryogenesis varies among different species: Aedes aegypti, Anopheles aquasalis and Culex quinquefasciatus eggs can survive in a dry environment for ≥ 72, 24 and 5 hours, respectively. In some adult insects, darker-body individuals show greater resistance to desiccation than lighter ones. We asked if egg melanization enhances mosquito serosal cuticle-dependent ERD. Species with higher ERD at late embryogenesis exhibit more melanized eggshells. The melanization-ERD hypothesis was confirmed employing two Anopheles quadrimaculatus strains, the wild type and the mutant GORO, with a dark-brown and a golden eggshell, respectively. In all cases, serosal cuticle formation is fundamental for the establishment of an efficient ERD but egg viability outside the water is much higher in mosquitoes with darker eggshells than in those with lighter ones. The finding that pigmentation influences egg water balance is relevant to understand the evolutionary history of insect egg coloration. Since eggshell and adult cuticle pigmentation ensure insect survivorship in some cases, they should be considered regarding species fitness and novel approaches for vector or pest insects control.

A MIDGUT DIGESTIVE PHOSPHOLIPASE A2 IN LARVAL MOSQUITOES, AEDES ALBOPICTUS AND CULEX QUINQUEFASCIATUS

Science.gov (United States)

Phospholipase A2 (PLA2) is a secretory digestive enzyme that hydrolyzes ester bond at sn-2 position of dietary phospholipids, creating free fatty acid and lysophopholipid. The free fatty acids (arachidonic acid) are absorbed into midgut cells. Aedes albopictus and Culex quinquefasciatus digestive PL...

Mosquito Vector Diversity across Habitats in Central Thailand Endemic for Dengue and Other Arthropod-Borne Diseases

Science.gov (United States)

Thongsripong, Panpim; Green, Amy; Kittayapong, Pattamaporn; Kapan, Durrell; Wilcox, Bruce; Bennett, Shannon

2013-01-01

Recent years have seen the greatest ecological disturbances of our times, with global human expansion, species and habitat loss, climate change, and the emergence of new and previously-known infectious diseases. Biodiversity loss affects infectious disease risk by disrupting normal relationships between hosts and pathogens. Mosquito-borne pathogens respond to changing dynamics on multiple transmission levels and appear to increase in disturbed systems, yet current knowledge of mosquito diversity and the relative abundance of vectors as a function of habitat change is limited. We characterize mosquito communities across habitats with differing levels of anthropogenic ecological disturbance in central Thailand. During the 2008 rainy season, adult mosquito collections from 24 sites, representing 6 habitat types ranging from forest to urban, yielded 62,126 intact female mosquitoes (83,325 total mosquitoes) that were assigned to 109 taxa. Female mosquito abundance was highest in rice fields and lowest in forests. Diversity indices and rarefied species richness estimates indicate the mosquito fauna was more diverse in rural and less diverse in rice field habitats, while extrapolated estimates of true richness (Chao1 and ACE) indicated higher diversity in the forest and fragmented forest habitats and lower diversity in the urban. Culex sp. (Vishnui subgroup) was the most common taxon found overall and the most frequent in fragmented forest, rice field, rural, and suburban habitats. The distributions of species of medical importance differed significantly across habitat types and were always lowest in the intact, forest habitat. The relative abundance of key vector species, Aedes aegypti and Culex quinquefasciatus, was negatively correlated with diversity, suggesting that direct species interactions and/or habitat-mediated factors differentially affecting invasive disease vectors may be important mechanisms linking biodiversity loss to human health. Our results are an

[Twenty-year surveillance of insects relevant to public health during the construction of hydroelectric facilities in Antioquia, Colombia].

Science.gov (United States)

Zuluaga, Walter Alonso; López, Yolanda Lucía; Osorio, Lisardo; Salazar, Luis Fernando; González, Marta Claudia; Ríos, Claudia María; Wolff, Marta Isabel; Escobar, José Pablo

2012-09-01

Entomological studies conducted in large hydroelectric infrastructure projects are a tool for the prevention and control of vector-borne diseases. These diseases emerge as a consequence of changes made to the terrain that often increase the natural and artificial mosquito larval habitats. Many of these insects are of public health importance and population increases result in an increased risk of disease transmission. The culicine (mosquito) and phlebotomine (sand fly) populations were characterized in the area of the Porce II and Porce III hydroelectric projects of Antioquia between 1990 to 2009. Periodical entomological samplings were made in the area of impact, in the workers camps, and construction sites. Adult specimens were captured with nets, Shannon light traps, CDC light traps, and protected human bait. Mosquito larvae of the following species were identified: Culex coronator, Culex nigripalpus, Culex corniger, Culex quinquefasciatus and Limatus durhami. The most frequently identifiers of larval habitats were low tanks, waste cans, tires, and aquatic plants. Aedes aegypti specimens were captured in only two rural locations from two municipalities within the area of influence. Specimens from the following mosquito genera were captured in forest areas: Aedes, Mansonia, Culex, Psorophora, Wyeomyia, Phonyomyia, Uranotaenia, Haemagogus and Sabethes. The most important mosquito found was Haemogogus janthinomis, an efficient yellow fever vector in Colombia. The area has been endemic for leishmaniasis and in the current study, 20 species of Lutzomyia sand flies, potential vectors, were identified. Among malaria vectors, the most important species found in the area were Anopheles nuneztovari and Anopheles pseudopunctipennis. A wide variety of vectors were discovered in the area of the Porce II and Porce III hydroelectric projects, and many of these were relevant for public health. Further monitoring will be necessary to minimize disease transmission risks among the

Regulation of P450-mediated permethrin resistance in Culex quinquefasciatus by the GPCR/Gαs/AC/cAMP/PKA signaling cascade.

Science.gov (United States)

Li, Ting; Liu, Nannan

2017-12-01

This study explores the role of G-protein-coupled receptor-intracellular signaling in the development of P450-mediated insecticide resistance in mosquitoes, Culex quinquefasciatus , focusing on the essential function of the GPCRs and their downstream effectors of Gs alpha subunit protein (Gαs) and adenylyl cyclase (ACs) in P450-mediated insecticide resistance of Culex mosquitoes. Our RNAi-mediated functional study showed that knockdown of Gαs caused the decreased expression of the downstream effectors of ACs and PKAs in the GPCR signaling pathway and resistance P450 genes, whereas knockdown of ACs decreased the expression of PKAs and resistance P450 genes. Knockdown of either Gαs or ACs resulted in an increased susceptibility of mosquitoes to permethrin. These results add significantly to our understanding of the molecular basis of resistance P450 gene regulation through GPCR/Gαs/AC/cAMP-PKA signaling pathways in the insecticide resistance of mosquitoes. The temporal and spatial dynamic analyses of GPCRs, Gαs, ACs, PKAs, and P450s in two insecticide resistant mosquito strains revealed that all the GPCR signaling pathway components tested, namely GPCRs, Gαs, ACs and PKAs, were most highly expressed in the brain for both resistant strains, suggesting the role played by these genes in signaling transduction and regulation. The resistance P450 genes were mainly expressed in the brain, midgut and malpighian tubules (MTs), suggesting their critical function in the central nervous system and importance for detoxification. The temporal dynamics analysis for the gene expression showed a diverse expression profile during mosquito development, indicating their initially functional importance in response to exposure to insecticides during their life stages.

Molecular characterization of novel mosquito-borne Rickettsia spp. from mosquitoes collected at the Demilitarized Zone of the Republic of Korea.

Science.gov (United States)

Maina, Alice N; Klein, Terry A; Kim, Heung-Chul; Chong, Sung-Tae; Yang, Yu; Mullins, Kristin; Jiang, Ju; St John, Heidi; Jarman, Richard G; Hang, Jun; Richards, Allen L

2017-01-01

Rickettsiae are associated with a diverse range of invertebrate hosts. Of these, mosquitoes could emerge as one of the most important vectors because of their ability to transmit significant numbers of pathogens and parasites throughout the world. Recent studies have implicated Anopheles gambiae as a potential vector of Rickettsia felis. Herein we report that a metagenome sequencing study identified rickettsial sequence reads in culicine mosquitoes from the Republic of Korea. The detected rickettsiae were characterized by a genus-specific quantitative real-time PCR assay and sequencing of rrs, gltA, 17kDa, ompB, and sca4 genes. Three novel rickettsial genotypes were detected (Rickettsia sp. A12.2646, Rickettsia sp. A12.2638 and Rickettsia sp. A12.3271), from Mansonia uniformis, Culex pipiens, and Aedes esoensis, respectively. The results underscore the need to determine the Rickettsia species diversity associated with mosquitoes, their evolution, distribution and pathogenic potential.

Identification of entomopathogenic Bacillus isolated from Simulium (Diptera, Simuliidae larvae and adults

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Cavados CFG

2001-01-01

Full Text Available Entomopathogenic bacteria isolated from Simulium larvae and adults from breeding sites in the states of São Paulo and Rio de Janeiro, Brazil, were identified as 18 strains of Bacillus thuringiensis and one of B. sphaericus. Most of these strains were serotyped according to their flagellar antigens. However, nine of the B. thuringiensis samples, could not be serotyped and were designated as "autoagglutinating"; they were also shown to be toxic in preliminary tests against Aedes aegypti larvae. Additionally, B. sphaericus was also shown to be toxic towards Culex quinquefasciatus larvae.

Comparative assessment of the bacterial communities associated with Aedes aegypti larvae and water from domestic water storage containers.

Science.gov (United States)

Dada, Nsa; Jumas-Bilak, Estelle; Manguin, Sylvie; Seidu, Razak; Stenström, Thor-Axel; Overgaard, Hans J

2014-08-24

Domestic water storage containers constitute major Aedes aegypti breeding sites. We present for the first time a comparative analysis of the bacterial communities associated with Ae. aegypti larvae and water from domestic water containers. The 16S rRNA-temporal temperature gradient gel electrophoresis (TTGE) was used to identify and compare bacterial communities in fourth-instar Ae. aegypti larvae and water from larvae positive and negative domestic containers in a rural village in northeastern Thailand. Water samples were cultured for enteric bacteria in addition to TTGE. Sequences obtained from TTGE and bacterial cultures were clustered into operational taxonomic units (OTUs) for analyses. Significantly lower OTU abundance was found in fourth-instar Ae. aegypti larvae compared to mosquito positive water samples. There was no significant difference in OTU abundance between larvae and mosquito negative water samples or between mosquito positive and negative water samples. Larval samples had significantly different OTU diversity compared to mosquito positive and negative water samples, with no significant difference between mosquito positive and negative water samples. The TTGE identified 24 bacterial taxa, belonging to the phyla Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes and TM7 (candidate phylum). Seven of these taxa were identified in larval samples, 16 in mosquito positive and 13 in mosquito negative water samples. Only two taxa, belonging to the phyla Firmicutes and Actinobacteria, were common to both larvae and water samples. Bacilli was the most abundant bacterial class identified from Ae. aegypti larvae, Gammaproteobacteria from mosquito positive water samples, and Flavobacteria from mosquito negative water samples. Enteric bacteria belonging to the class Gammaproteobacteria were sparsely represented in TTGE, but were isolated from both mosquito positive and negative water samples by selective culture. Few bacteria from water samples were

Molecular DNA identification of blood sources fed on, for Culicine mosquitoes (Diptera: Culicidae collected in the Songkhla province, southern Thailand

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Theerakamol Pengsakul

2017-12-01

Full Text Available Culicine mosquitoes are medically important vectors. Therefore, mosquito control measures are a crucial strategy to interrupt disease transmission. Collection of data on mosquito feeding patterns is crucial for developing an effective vector control strategy. The objective of this study was to use molecular biology methods to identify the sources of DNA in mosquito blood meals. The DNA from blood meals in the mosquito stomachs was extracted and amplified with multiplex PCR, using specific primer sets based on the mitochondrial cytochrome b gene, to identify the DNA sources among human, pig, goat, dog, cow, and chicken. Among the 297 mosquito samples collected in the Songkhla province of Thailand, in Aedes spp. mosquitoes the percentages positive for human, dog, pig, chicken, cow, a mixture of 2 vertebrate DNAs, or of 3, and negative (no identified DNA were 61.90, 2.38, 2.38, 0.60, 0.60, 4.18, 1.20 and 26.79% respectively. In Culex spp. blood meals the rank order was different: fractions positive for chicken, human, dog, cow, goat, pig, a mixture of 2 or 3 vertebrate DNAs, and negative were 40.83, 10.00, 5.00, 4.17, 1.67, 0.83, 8.32, 3.32 and 25.83% respectively. This study shows that feeding behaviors of the two species differ, with most Aedes spp. blood meals containing human blood, while Culex spp. had primarily consumed chicken blood. An improved understanding of the feeding behaviors of mosquitoes could contribute to new, more effective strategies for the control of mosquito populations.

SYBR green-based one step quantitative real-time polymerase chain reaction assay for the detection of Zika virus in field-caught mosquitoes.

Science.gov (United States)

Tien, Wei-Ping; Lim, Gareth; Yeo, Gladys; Chiang, Suzanna Nicole; Chong, Chee-Seng; Ng, Lee-Ching; Hapuarachchi, Hapuarachchige Chanditha

2017-09-19

The monitoring of vectors is one of the key surveillance measures to assess the risk of arbovirus transmission and the success of control strategies in endemic regions. The recent re-emergence of Zika virus (ZIKV) in the tropics, including Singapore, emphasizes the need to develop cost-effective, rapid and accurate assays to monitor the virus spread by mosquitoes. As ZIKV infections largely remain asymptomatic, early detection of ZIKV in the field-caught mosquitoes enables timely implementation of appropriate mosquito control measures. We developed a rapid, sensitive and specific real-time reverse transcription polymerase chain reaction (rRT-PCR) assay for the detection of ZIKV in field-caught mosquitoes. The primers and PCR cycling conditions were optimized to minimize non-specific amplification due to cross-reactivity with the genomic material of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, Culex tritaeniorhynchus, Culex sitiens and Anopheles sinensis, as well as accompanying microbiota. The performance of the assay was further evaluated with a panel of flaviviruses and alphaviruses as well as in field-caught Ae. aegypti mosquitoes confirmed to be positive for ZIKV. As compared to a probe-based assay, the newly developed assay demonstrated 100% specificity and comparable detection sensitivity for ZIKV in mosquitoes. Being a SYBR Green-based method, the newly-developed assay is cost-effective and easy to adapt, thus is applicable to large-scale vector surveillance activities in endemic countries, including those with limited resources and expertise. The amplicon size (119 bp) also allows sequencing to confirm the virus type. The primers flank relatively conserved regions of ZIKV genome, so that, the assay is able to detect genetically diverse ZIKV strains. Our findings, therefore, testify the potential use of the newly-developed assay in vector surveillance programmes for ZIKV in endemic regions.

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

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V. Thenmozhi

2014-03-01

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

Effect of seed kernel aqueous extract from Annona squamosa against three mosquito vectors and its impact on non-target aquatic organisms

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Ravichandran Ramanibai

2016-09-01

Full Text Available Objective: To evaluate the toxicity of Annona squamosa (A. squamosa aqueous (physiological saline seed soluble extract and its control of mosquito population. Methods: Ovicidal, larvicidal and pupicidal activity of A. squamosa crude soluble seed kernel extract was determined according to World Health Organization. The mortality of each mosquito stage was recorded after 24 h exposured to plant material. Toxicity assay was used to assess the non-target organisms with different concentrations according to Organisation for Economic Co-operation and Development. Results: The aqueous solubilized extracts of A. squamosa elicit the toxicity against all stages of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus, and the LC50 values against stages of egg, 1st-4th larvae were (1.45 and 1.26–2.5 mg/mL, (1.12 and 1.19–2.81 mg/ mL and (1.80 and 2.12–3.41 mg/mL respectively. The pupicidal activity also brought forth amended activity against all three mosquitoes species, and the LC50 values were consider to be 3.19, 2.42 and 4.47 mg/mL. Ultimately there was no mortality observed from non-target organism of Chironomus costatus. Conclusions: Based on the findings of the study, it suggests that the use of A. squamosa plant extract can act as an alternate insecticidal agents for controlling target mosquitoes without affecting the non-target aquatic insect. Further investigation to identify the active compounds and their mechanisms of action is recommended.

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

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

2007-01-01

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

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

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

2006-11-01

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

Preferências alimentares e domiciliação de mosquitos Culicidae no Vale do Ribeira, São Paulo, Brasil, com especial referência a Aedes scapularis e a Culex (Melanoconion Feeding preferences and domiciliation of Culicidae mosquitoes in the Ribeira Valley, S. Paulo State, Brazil, with particular reference to Aedes scapularis and Culex (Melanoconion

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Oswaldo Paulo Forattini

1989-02-01

Full Text Available Apresentam-se novos dados sobre a identificação do sangue ingerido por culicídeos ingurgitados e coletados em quatro localidades do Vale do Ribeira, Estado de São Paulo (Brasil, no período de fevereiro a novembro de 1986, e que já tinham sido sede de observações anteriores. São fornecidos dados sobre a distribuição de algumas espécies relacionadas ao tipo de ambiente. Focalizam-se Ae. scapularis e representantes de Culex (Melanoconion, principalmente Cx. ribeirensis e Cx. sacchettae. Foi possível a identificação de 651 repastos sangüíneos. Confirmou-se a preferência de Ae. scapularis por mamíferos de grande porte representados por bovinos, eqüinos e o próprio homem, tendo reagido a todos os anti-soros testados, com exceção do correspondente a animais de sangue frio representados por anfíbio. Cx. ribeirensis revelou resultados que sugerem possível preferência por mamíferos. As duas espécies supracitadas mostram tendência nítida para adaptação ao ambiente modificado pelo homem e capacidade de evolução de seus hábitos de possível domiciliação. Quanto aos outros culicídeos, as coletas de An. bellator, An. cruzii e Cq. chrysonotum limitaram-se à isca humana que a segunda dessas espécies rendeu 31,6% do total de fêmeas capturadas.New results on blood-meal identification and the environmental distribution of mosquitoes collected in four different Ribeira Valley (S. Paulo State, Brazil environments, during the period February to November 1986, are presented. Sources of 651 blood-meals were identified. The preference of Ae. scapularis for large mammals, chiefly cattle, horse and even man, was confirmed. Data suggests that a similar behavioral pattern is presented by Cx. ribeirensis. Both mosquitoes seem to be strongly attracted by peridomiciliar blood sources represented by domestic animals sheltered in that environment. Nevertheless, the female of Ae. scapularis females may use the extradomiciliary environment

Preferências alimentares de mosquitos Culicidae no Vale do Ribeira, São Paulo, Brasil Feeding preferences of Culicidae mosquitoes in the Ribeira Valley, S.Paulo State, Brazil

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Oswaldo Paulo Forattini

1987-06-01

Full Text Available São apresentados os resultados obtidos na identificação do sangue ingerido por culicídeos ingurgitados coletados em vários ambientes rurais de cinco localidades do Vale do Ribeira, Estado de São Paulo (Brasil. O maior rendimento, que representou a quase totalidade dos espécimens coletados, foi obtido mediante o emprego da aspiração e das redes manuais. Foi possível identificar a origem de 1.444 repastos sangüíneos. Os Aedes apresentaram predominância de positividade para mamíferos. Ae. scapularis mostrou preferência por hospedeiros de grande porte representados por bovinos e eqüinos. Ae. serratus alimentou-se também em aves. Com exceção da elevada antropofilia de Cx. quinquefasciatus, os demais representantes de Cx. (Culex revelaram-se apreciavelmente ornitófilos. Em conjunto, Cx. (Melanoconion mostrou o mais amplo espectro de hematofagia, que incluiu anfíbio, ave, mamíferos e réptil. Cx. ribeirensis e Cx. sacchettae apresentaram resultados que sugerem alguma preferência por mamíferos. A antropofilia distribuiu-se por várias espécies destacando-se Ae. scapularis, Cx. sacchettae e Cx. ribeirensis que a apresentaram nas coletas efetuadas no intradomicílio. A influência da densidade de hospedeiros no ambiente modificado fez-se sentir em relação à primeira dessas três espécies, para as quais as evidências obtidas sugerem que estejam evoluindo no sentido da domiciliação.Results of blood-meal identification for mosquitoes collected in 5 different Ribeira Valley (S.Paulo State, Brazil environments are presented. Precipitin tests identified the sources of 1444 blood-meals. Aedes mosquitoes fed chiefly on mammals. Ae. scapularis showed a preference for cattle and horses. Ae. serratus also obtained meals from avian hosts. Leaving aside the anthropophilic Cx.quinquefasciatus, the other Culex (Culex mosquitoes showed feeding pattern directed to avian hosts. On the whole Culex (Melanoconion showed a largely eclectic

Zika mosquito vectors: the jury is still out [version 1; referees: 5 approved

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Walter S. Leal

2016-10-01

Full Text Available After a 40-year hiatus, the International Congress of Entomology (ICE 2016 convened in Orlando, Florida (September 25-30, 2016. One of the symposia at ICE 2016, the Zika Symposium, covered multiple aspects of the Zika epidemic, including epidemiology, sexual transmission, genetic tools for reducing transmission, and particularly vector competence. While there was a consensus among participants that the yellow fever mosquito, Aedes aegypti, is a vector of the Zika virus, there is growing evidence indicating that the range of mosquito vectors might be wider than anticipated. In particular, three independent groups from Canada, China, and Brazil presented and discussed laboratory and field data strongly suggesting that the southern house mosquito, Culex quinquefasciatus, also known as the common mosquito, is highly likely to be a vector in certain environments.

Zika mosquito vectors: the jury is still out [version 2; referees: 5 approved

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Walter S. Leal

2016-11-01

Full Text Available After a 40-year hiatus, the International Congress of Entomology (ICE 2016 convened in Orlando, Florida (September 25-30, 2016. One of the symposia at ICE 2016, the Zika Symposium, covered multiple aspects of the Zika epidemic, including epidemiology, sexual transmission, genetic tools for reducing transmission, and particularly vector competence. While there was a consensus among participants that the yellow fever mosquito, Aedes aegypti, is a vector of the Zika virus, there is growing evidence indicating that the range of mosquito vectors might be wider than anticipated. In particular, three independent groups from Canada, China, and Brazil presented and discussed laboratory and field data strongly suggesting that the southern house mosquito, Culex quinquefasciatus, also known as the common mosquito, is highly likely to be a vector in certain environments.

Receptor protein of Lysinibacillus sphaericus mosquito-larvicidal toxin displays amylomaltase activity.

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Sharma, Mahima; Gupta, Gagan D; Kumar, Vinay

2018-02-01

The activated binary toxin (BinAB) from Lysinibacillus sphaericus binds to surface receptor protein (Cqm1) on the midgut cell membrane and kills Culex quinquefasciatus larvae on internalization. Cqm1 is attached to cells via a glycosyl-phosphatidylinositol (GPI) anchor. It has been classified as a member of glycoside hydrolase family 13 of the CAZy database. Here, we report characterization of the ordered domain (residues 23-560) of Cqm1. Gene expressing Cqm1 of BinAB susceptible mosquito was chemically synthesized and the protein was purified using E. coli expression system. Values for the Michaelis-Menten kinetics parameters towards 4-nitrophenyl α-D-glucopyranoside (α-pNPG) substrate were estimated to be 0.44 mM (Km) and 1.9 s -1 (kcat). Thin layer chromatography experiments established Cqm1 as α-glucosidase competent to cleave α-1,4-glycosidic bonds of maltose and maltotriose with high glycosyltransferase activity to form glucose-oligomers. The observed hydrolysis and synthesis of glucose-oligomers is consistent with open and accessible active-site in the structural model. The protein also hydrolyses glycogen and sucrose. These activities suggest that Cqm1 may be involved in carbohydrate metabolism in mosquitoes. Further, toxic BinA component does not inhibit α-glucosidase activity of Cqm1, while BinB reduced the activity by nearly 50%. The surface plasmon resonance study reveals strong binding of BinB with Cqm1 (Kd, 9.8 nM). BinA interaction with Cqm1 however, is 1000-fold weaker. Notably the estimated Kd values match well with dissociation constants reported earlier with larvae brush border membrane fractions. The Cqm1 protein forms a stable dimer that is consistent with its apical localization in lipid rafts. Its melting temperature (T m ) as observed by thermofluor-shift assay is 51.5 °C and Ca 2+ provides structural stability to the protein. Copyright © 2017 Elsevier Ltd. All rights reserved.

Drinking a hot blood meal elicits a protective heat shock response in mosquitoes.

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Benoit, Joshua B; Lopez-Martinez, Giancarlo; Patrick, Kevin R; Phillips, Zachary P; Krause, Tyler B; Denlinger, David L

2011-05-10

The mosquito's body temperature increases dramatically when it takes a blood meal from a warm-blooded, vertebrate host. By using the yellow fever mosquito, Aedes aegypti, we demonstrate that this boost in temperature following a blood meal prompts the synthesis of heat shock protein 70 (Hsp70). This response, elicited by the temperature of the blood meal, is most robust in the mosquito's midgut. When RNA interference is used to suppress expression of hsp70, protein digestion of the blood meal is impaired, leading to production of fewer eggs. We propose that Hsp70 protects the mosquito midgut from the temperature stress incurred by drinking a hot blood meal. Similar increases in hsp70 were documented immediately after blood feeding in two other mosquitoes (Culex pipiens and Anopheles gambiae) and the bed bug, Cimex lectularius, suggesting that this is a common protective response in blood-feeding arthropods.

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

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Mélissanne de Wispelaere

2017-01-01

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

Effect of environmental temperature on the vector competence of mosquitoes for Rift Valley fever virus

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Environmental temperature has been shown to affect the ability of mosquitoes to transmit numerous arboviruses and for Rift Valley fever virus (RVFV) in particular. We evaluated the effect of incubation temperatures ranging from 14-26ºC on infection, dissemination, and transmission rates for Culex ta...

Design and development of aqueous nanoformulations for mosquito control.

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Montefuscoli, Antonela Rita; Werdin González, Jorge Omar; Palma, Santiago Daniel; Ferrero, Adriana Alicia; Fernández Band, Beatriz

2014-02-01

Microemulsions (ME) are thermodynamically stable isotropic mixtures of oil, water, and surfactant; they would also be attractive as potential insecticidal products due to the high bioviability of the active ingredient, attributable to the small sizes of the oil drops. A laboratory study was conducted in order to compare the biological effect of oil in water (o/w) geranium essential oil (EO) and geraniol MEs and emulsions, against Culex pipiens pipiens mosquito larvae. The systems were based on three nonionic surfactants (Cremophor EL, Brij 35, Tween 80). The MEs showed dispersed phase diameters in the range of 8 to 14 nm and had low PDI values (<0.2). The MEs were analyzed by TEM, indicating that they had nearly spherical morphology. The microemulsified systems based on geranium EO and those of geraniol produced a notable increase of the larvicidal activity when compared with the respectably emulsions, concluding that the biological effect is related with the diameter of the dispersed phase. The smallest drops achieved the highest larvicidal activity, being the aqueous nanoformulations based on geraniol most effective than those of geranium EO. However, geranium microemulsions are preferred due to their residual toxicological profiles. The results indicate that these novel systems could be used in integrated pest management program for the C. pipiens pipiens.

Factors influencing the spatial distribution of Anopheles larvae in Coimbatore District, Tamil Nadu, India.

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Arjunan, Naresh Kumar; Kadarkarai, Murugan; Kumar, Shobana; Pari, Madhiyazhagan; Thiyagarajan, Nataraj; Vincent, C Thomas; Barnard, Donald R

2015-12-01

Malaria causes extensive morbidity and mortality in humans and results in significant economic losses in India. The distribution of immature malaria-transmitting Anopheles mosquitoes was studied in 17 villages in Coimbatore District as a prelude to the development and implementation of vector control strategies that are intended to reduce the risk of human exposure to potentially infectious mosquitoes. Eight Anopheles species were recorded. The most numerous species were Anopheles vagus, Anopheles subpictus, and Anopheles hyrcanus. The location of mosquito development sites and the density of larvae in each village was evaluated for correlation with selected demographic, biologic, and land use parameters using remote sensing and geographic information systems (GIS) technology. We found the number of mosquito development sites in a village and the density of larvae in such sites to be positively correlated with human population density but not the surface area (km(2)) of the village. The number of mosquito development sites and the density of larvae in each site were not correlated. Data from this study are being used to construct a GIS-based mapping system that will enable the location of aquatic habitats with Anopheles larvae in the Coimbatore District, Tamil Nadu, India as target sites for the application of vector control. Copyright © 2015 Elsevier B.V. All rights reserved.

Field trial of the spatial repellency of metofluthrin-impregnated plastic strip against mosquitoes in shelters without walls (Beruga) in Lombok, Indonesia.

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Kawada, Hitoshi; Maekawa, Yoshihide; Takagi, Masahiro

2005-01-01

Field trials on the spatial repellency of metofluthrin-impregnated plastic strips for mosquitoes present in shelters without walls (beruga) were carried out in Lombok, Indonesia. A major reduction in the incidence of human biting by Culex quinquefasciatus was achieved, and the use of two strips per beruga repelled >60% of the mosquitoes for at least 11 wk while four strips repelled >60% of the mosquitoes for more than 15 weeks. The technique was found to be a practical long-term solution for ...

Evaluation of Isotope 32P Method to Mark Culex pipiens (Diptera: Culicidae in a Laboratory

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Chongxing Zhang

2016-01-01

Full Text Available Background: The aim of the current study was to develop a marking technique as an internal marker to mark post blood meal mosquitoes by using stable phosphate isotope 32P and determine the optimal concentration of it.Methods: An isotonic physiological saline solution, containing different concentration of radioactive isotope 32P-labeled disodium phosphate (Na2H32PO4 was injected into rabbits via the jugular vein in the laboratory. Emerged Cx. pipiens were marked after feeding on rabbit. At the same time, the labeled conditions of emerged Cx. pipiens were also measured by placing feces of No. 6 rabbit into containers with mosquito larvae and pupae inside.Results: According to the label condition of Cx. pipiens after taking blood and the effect of different dosage Na2H32PO4 on rabbit health, the optimal concentration of radioactive isotope was determined, that is, 0.1211 mCi/kg. By placing feces of No. 6 rabbit into containers with mosquito larvae and pupae inside, the emerged mosquitoes were also labeled. Therefore, feeding mosquitoes on the animal injected with radioactive Na2H32PO4 was more prac­tical for detecting and tracing mosquitoes.Conclusion: The method was less time-consuming, more sensitive and safer. This marking method will facilitate post-bloodmeal studies of mosquitoes and other blood-sucking insects.

Viral Interference and Persistence in Mosquito-Borne Flaviviruses

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Juan Santiago Salas-Benito

2015-01-01

Full Text Available Mosquito-borne flaviviruses are important pathogens for humans, and the detection of two or more flaviviruses cocirculating in the same geographic area has often been reported. However, the epidemiological impact remains to be determined. Mosquito-borne flaviviruses are primarily transmitted through Aedes and Culex mosquitoes; these viruses establish a life-long or persistent infection without apparent pathological effects. This establishment requires a balance between virus replication and the antiviral host response. Viral interference is a phenomenon whereby one virus inhibits the replication of other viruses, and this condition is frequently associated with persistent infections. Viral interference and persistent infection are determined by several factors, such as defective interfering particles, competition for cellular factors required for translation/replication, and the host antiviral response. The interaction between two flaviviruses typically results in viral interference, indicating that these viruses share common features during the replicative cycle in the vector. The potential mechanisms involved in these processes are reviewed here.

Biotin/avidin sandwich enzyme-linked immunosorbent assay for Culicidae mosquito blood meal identification

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A. M. Marassá

2008-01-01

Full Text Available The knowledge of mosquitoes Culicidae host feeding patterns is basic to understand the roles of different species and to indicate their importance in the epidemiology of arthropod-borne diseases. A laboratory assay was developed aiming at standardizing the biotin-avidin sandwich enzyme-linked immunosorbent assay, which was unprecedented for mosquito blood meal identification. The enzyme-linked immunosorbent assay (ELISA activity was evaluated by the detection of titers on each sample of the 28 blood-fed Culex quinquefasciatus. In light of the high sensitivity that the technique permits, by means of small quantities of specific antibodies commercially provided and phosphatase substrate which reinforces additional dilutions, human and rat blood meals were readily identified in all laboratory-raised Culex quinquefasciatus tested. The assay was effective to detect human blood meal dilutions up to 1:4,096, which enables the technique to be applied in field studies. Additionally, the present results indicate a significant difference between the detection patterns recorded from human blood meal which corroborate the results of host feeding patterns.

Field trial on the spatial repellency of metofluthrin-impregnated plastic strips for mosquitoes in shelters without walls (beruga) in Lombok, Indonesia.

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Kawada, Hitoshi; Maekawa, Yoshihide; Takagi, Masahiro

2005-12-01

Field trials on the spatial repellency of metofluthrin-impregnated plastic strips for mosquitoes present in shelters without walls (beruga) were carried out in Lombok, Indonesia. A major reduction in the incidence of human biting by Culex quinquefasciatus was achieved, and the use of two strips per beruga repelled >60% of the mosquitoes for at least 11 wk while four strips repelled >60% of the mosquitoes for more than 15 weeks. The technique was found to be a practical long-term solution for the prevention of mosquito bites without using electricity or heat to evaporate the metofluthrin.

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

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

2011-03-01

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

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

Surveillance of Mosquitoes and Selected Arthropod-Borne Viruses in the Context of Milan EXPO 2015

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Mario Chiari

2016-07-01

Full Text Available From 1 May 2015 to 31 October 2015 over 20 million visitors from all over the world visited the Universal Exhibition (EXPO hosted by Milan (Lombardy region, Italy, raising concerns about the possible introduction of mosquito-borne diseases from endemic countries. The entomological surveillance protocol performed in Lombardy over the last three years was implemented in the EXPO area and in the two major regional airports using both Center for Disease Control CO2 and Biogents Sentinel traps. This surveillance aimed to estimate the presence and densities of putative vectors, and also to support investigations, including the vector species involved and area of diffusion, on the local spread of Chikungunya, Dengue and West Nile viruses (WNV by competent vectors. From 3544 mosquitoes belonging to five different species, 28 pools of Culex spp. and 45 pools of Aedes spp. were screened for the presence of WNV, and for both Chikungunya and flaviviruses, respectively. The entomological surveillance highlighted a low density of potential vectors in the surveyed areas and did not reveal the presence of Chikungunya or Dengue viruses in the local competent vectors inside the EXPO area or in the two airports. In addition, the surveillance reported a low density of Culex spp. mosquitoes, which all tested negative for WNV.

Evaluation of larvicidal activity of medicinal plant extracts against three mosquito vectors.

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Bagavan, A; Rahuman, A Abdul

2011-01-01

To evaluate the mosquito larvicidal activity of plant extracts. The hexane, chloroform, ethyl acetate, acetone, and methanol leaf, flower and seed extracts of Abrus precatorius (A. precatorius), Croton bonplandianum (C. bonplandianum), Cynodon dactylon (C. dactylon), Musa paradisiaca (M. paradisiaca) and Syzygium aromaticum (S. aromaticum) were tested against fourth instar larvae of Anopheles vagus (An. vagus), Armigeres subalbatus (Ar. subalbatus) and Culex vishnui (Cx. vishnui). The highest larval mortality was found in seed ethyl acetate extracts of A. precatorius and leaf extracts of C. bonplandianum, flower chloroform and methanol extracts of M. paradisiaca, and flower bud hexane extract of S. aromaticum against An. vagus with LC(50) values of 19.31, 39.96, 35.18, 79.90 and 85.90 μg/mL; leaf ethyl acetate and methanol extracts of C. dactylon, flower methanol extract of M. paradisiaca, flower bud methanol extract of S. aromaticum against Ar. subalbatus with LC(50) values of 21.67, 32.62, 48.90 and 78.28 μg/mL, and seed methanol of A. precatorius, flower methanol extract of M. paradisiaca, flower bud hexane extract of S. aromaticum against Cx. vishnui with LC(50) values of 136.84, 103.36 and 149.56 μg/mL, respectively. These results suggest that the effective plant crude extracts have the potential to be used as an ideal ecofriendly approach for the control of disease vectors. This study provides the first report on the larvicidal activity of crude solvent extracts of different mosquitoes. Copyright © 2011 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Synergistic effect of certain insecticides combined with Bacillus thuringiensis on mosquito larvae

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C.P. Narkhede

2017-04-01

Full Text Available For effective vector control it is essential to formulate new preparations having multiple action against the vector pest. Developing combined formulation of biopesticide and chemical pesticide is one of the novel concept to fight against the vectors with new weapons; however, compatibility of biopesticide i.e. Bacillus thuringiensis (Bt and chemical pesticide is a real hurdle. In this investigation, local isolate Bacillus thuringiensis SV2 (BtSV2 was tested for its compatibility with various available mosquito larvicides. Temephos was most compatible with BtSV2 than with other tested pesticides. These two compatible agents were tested for larvicidal potential. Our study revealed that the synergistic effect of both agents reduces LC50 value by 30.68 and 22.36% against the Ae. aegypti and An. stephensi, respectively. The larvicidal potential increased when compared to individual pesticides. It was also observed a biochemical change in larvae after the TBT (Temephos + Bacillus thuringiensis combination treatment; it involves decreased level of alpha esterase, acetylcholine esterase and protein while level of beta esterase and acid phosphatase was unchanged and alkaline phosphatase activity was increased. Increased potential of combined formulation may be due to altered physiological condition.

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

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Carlos Fernando S. de Andrade

1990-08-01

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

Odonate Nymphs: Generalist Predators and their Potential in the Management of Dengue Mosquito, Aedes aegypti (Diptera: Culicidae

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Waseem Akram

2016-01-01

Full Text Available Background: Dengue is amongst the most serious mosquito-borne infectious disease with hot spots in tropical and subtropical parts of the world. Unfortunately, no licensed vaccine for the disease is currently available in medicine markets. The only option available is the management of dengue vector mosquito, Aedes aegypti (Diptera: Culicidae.Method: Predatory potential of five odonate nymphs namely Anax parthenope, Bradinopyga geminate, Ischnura forcipata, Rhinocypha quadrimaculata, and Orthetrum sabina were evaluated against the 4th instar larvae of the den­gue vector mosquito, Aedes aegypti, under laboratory conditions. The consumption of the mosquito larvae was eval­uated at three water volume levels viz., 1 liter, 2 liter and 3 liter.Results: The number of Ae. aegypti larvae consumed varied significantly among the five species, and at different levels of water volume (P< 0.01. However, the interaction between odonate nymphs and the water volumes was statistically non-significant (P> 0.05. Ischnura forcipata consumed the highest number of Ae. aegypti larvae (n=56 followed by A. parthenope (n=47 and B. geminate (n=46. The number of larvae consumed was decreased with in­creasing search area or water volume, and the highest predation was observed at 1-liter water volume.Conclusion: The odonate nymphs could be a good source of biological agents for the management of the mosquitoes at larval stages. 

West Nile Virus: High Transmission Rate in North-Western European Mosquitoes Indicates Its Epidemic Potential and Warrants Increased Surveillance.

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Jelke J Fros

Full Text Available West Nile virus (WNV is a highly pathogenic flavivirus transmitted by Culex spp. mosquitoes. In North America (NA, lineage 1 WNV caused the largest outbreak of neuroinvasive disease to date, while a novel pathogenic lineage 2 strain circulates in southern Europe. To estimate WNV lineage 2 epidemic potential it is paramount to know if mosquitoes from currently WNV-free areas can support further spread of this epidemic.We assessed WNV vector competence of Culex pipiens mosquitoes originating from north-western Europe (NWE in direct comparison with those from NA. We exposed mosquitoes to infectious blood meals of lineage 1 or 2 WNV and determined the infection and transmission rates. We explored reasons for vector competence differences by comparing intrathoracic injection versus blood meal infection, and we investigated the influence of temperature. We found that NWE mosquitoes are highly competent for both WNV lineages, with transmission rates up to 25%. Compared to NA mosquitoes, transmission rates for lineage 2 WNV were significantly elevated in NWE mosquitoes due to better virus dissemination from the midgut and a shorter extrinsic incubation time. WNV infection rates further increased with temperature increase.Our study provides experimental evidence to indicate markedly different risk levels between both continents for lineage 2 WNV transmission and suggests a degree of genotype-genotype specificity in the interaction between virus and vector. Our experiments with varying temperatures explain the current localized WNV activity in southern Europe, yet imply further epidemic spread throughout NWE during periods with favourable climatic conditions. This emphasizes the need for intensified surveillance of virus activity in current WNV disease-free regions and warrants increased awareness in clinics throughout Europe.

Field trials with tank mixtures of Bacillus thuringiensis subsp. israelensis and Bacillus sphaericus formulations against Culex pipiens larvae in septic tanks in Antalya, Turkey.

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Cetin, Huseyin; Dechant, Peter; Yanikoglu, Atila

2007-06-01

Efficacy of tank mixtures of commercial Bacillus thuringiensis subsp. israelensis (Bti) and Bacillus sphaericus (Bs) water-dispersable granule (WDG) formulations was evaluated in septic tanks, against Culex pipiens L. (Diptera: Culicidae) larvae. VectoLex WDG (Bs) + VectoBac WDG (Bti) were evaluated at various ratios from 488 g/ha VectoLex + 250 g/ha VectoBac up to 3,000 g/ha of each. All applications and ratios delivering VectoLex WDG at a rate equal to or greater than 988 g/ha provided more than 90% control for 28 days after treatment. The lowest dose provided this level of control for at least 7 days after treatment, with greater than 80% control after 2 wk. These results suggest that a retreatment interval of 2 wk is recommended with the lowest dose and retreatment intervals of 4 or more wk are recommended with the doses equal to or higher than 988 g/ha VectoLex + 250 g/ha VectoBac.

Quantifying seasonal and diel variation in Anopheline and Culex human biting rates in Southern Ecuador.

Science.gov (United States)

Ryan, Sadie J; Lippi, Catherine A; Boersch-Supan, Philipp H; Heydari, Naveed; Silva, Mercy; Adrian, Jefferson; Noblecilla, Leonardo F; Ayala, Efraín B; Encalada, Mayling D; Larsen, David A; Krisher, Jesse T; Krisher, Lyndsay; Fregosi, Lauren; Stewart-Ibarra, Anna M

2017-11-22

Quantifying mosquito biting rates for specific locations enables estimation of mosquito-borne disease risk, and can inform intervention efforts. Measuring biting itself is fraught with ethical concerns, so the landing rate of mosquitoes on humans is often used as a proxy measure. Southern coastal Ecuador was historically endemic for malaria (Plasmodium falciparum and Plasmodium vivax), although successful control efforts in the 2000s eliminated autochthonous transmission (since 2011). This study presents an analysis of data collected during the elimination period. Human landing catch (HLC) data for three mosquito taxa: two malaria vectors, Anopheles albimanus and Anopheles punctimacula, and grouped Culex spp. were examined for this study. These data were collected by the National Vector Control Service of the Ministry of Health over a 5-year time span (2007-2012) in five cities in southern coastal Ecuador, at multiple households, in all months of the year, during dusk-dawn (18:00-6:00) hours, often at both indoor and outdoor locations. Hurdle models were used to determine if biting activity was fundamentally different for the three taxa, and to identify spatial and temporal factors influencing bite rate. Due to the many different approaches to studying and quantifying bite rates in the literature, a glossary of terms was created, to facilitate comparative studies in the future. Biting trends varied significantly with species and time. All taxa exhibited exophagic feeding behavior, and outdoor locations increased both the odds and incidence of bites across taxa. Anopheles albimanus was most frequently observed biting, with an average of 4.7 bites/h. The highest and lowest respective months for significant biting activity were March and July for An. albimanus, July and August for An. punctimacula, and February and July for Culex spp. Fine-scale differences in endophagy and exophagy, and temporal differences among months and hours exist in biting patterns among

Selected phenotypic features of BR91, a unique spirochaetal strainisolated from the Culex pipiens mosquito

Czech Academy of Sciences Publication Activity Database

Šikutová, Silvie; Buňková, L.; Krejčí, E.; Halouzka, Jiří; Sanogo, Y. O.; Rudolf, Ivo

2014-01-01

Roč. 169, 5-6 (2014), s. 348-352 ISSN 0944-5013 R&D Projects: GA ČR GA206/00/1234; GA ČR GA206/03/0726 Institutional support: RVO:68081766 Keywords : Spirochaete * Culex pipiens * Enzyme activity * SDS-PAGE * FAMEa Subject RIV: EE - Microbiology, Virology Impact factor: 2.561, year: 2014

Lista dos mosquitos da Bolívia: (Diptera, Culicidae

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N. L. Cerqueira

1943-08-01

Full Text Available Em quinze gêneros, cento e vinte e seis espécies de mosquitos foram constatadas no material capturado pelo Servicio de Fiebre Amarilla desde 1933 até 1942. Êste número, três vezes mais elevado do que o existente na literatura para o país, seria ainda maior se possível fôsse identificar sem o auxílio de machos inúmeras fêmeas das espécies de Culex. Tôdas as espécies estudadas apresentavam suas distribuições geográficas nos departamentos e províncias onde casos de Febre Amarela foram observados. Algumas cosiderações foram feitas em torno de espécies que não correspondiam exatamente com as descrições existentes, assim como descrições de outras foram dadas, cujos sexos opostos apenas eram conhecidos.One hundred and twenty-six species of mosquitoes, corresponding fifteen genera, have been found in material collected by the Bolivian Yellow Fever Service between 1933 and 1942. This number is three times that given for the country in existing literature and would be even largar if it were possible to identify a consierable group of Culex mosquitoes composed principally of female specimens. All species studied come from Departmetns and Provinces where cases of yellow fever have been found. Consideration has been given to certain species which do not agree exactly with existing descriptions, and supplementary descriptions have been made for the male or female of two additional species for which only description of the opposite sex had existed.

A list of mosquito species of the Brazilian State of Pernambuco, including the first report of Haemagogus janthinomys (Diptera: Culicidae, yellow fever vector and 14 other species (Diptera: Culicidae Lista de espécies de mosquitos do Estado de Pernambuco e primeiro relato de Haemagogus janthinomys (Diptera: Culicidae vetor de febre amarela silvestre e outras 14 espécies (Diptera: Culicidae

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Nádia Consuelo Aragão

2010-08-01

Full Text Available INTRODUCTION: Besides mosquito species adapted to urban environments (Culex quinquefasciatus, Aedes aegypti and Aedes albopictus, only 15 species of Anopheles had been recorded in the State of Pernambuco. METHODS: Human-landing mosquitoes were collected in Dois Irmãos Park, in Recife. RESULTS: The first report for the state of Haemagogus janthinomys, an important vector of yellow fever virus, and 14 other species, including Trichoprosopon lampropus, a first reported for Brazil. CONCLUSIONS: The mosquito fauna in the area is diversified and has potential medical and veterinary importance.INTRODUÇÃO: Além de mosquitos adaptados ao ambiente urbano (Culex quinquefasciatus, Aedes aegypti e Ae. albopictus, apenas 15 espécies de Anopheles haviam sido relatadas no Estado de Pernambuco. MÉTODOS: Mosquitos que pousavam em humanos no Parque Dois Irmãos, em Recife foram coletados. RESULTADOS: Haemagogus janthinomys, importante vetor de vírus de febre amarela, e outras 14 espécies são relatadas pela primeira vez no estado, incluindo Trichoprosopon lampropus, relatado pela primeira vez no Brasil. CONCLUSÕES: A fauna de mosquitos na área é muito diversificada e tem potencial importância médica e veterinária.

The Potential Use of Wolbachia-Based Mosquito Biocontrol Strategies for Japanese Encephalitis.

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Claire L Jeffries

Full Text Available Japanese encephalitis virus (JEV is a zoonotic pathogen transmitted by the infectious bite of Culex mosquitoes. The virus causes the development of the disease Japanese encephalitis (JE in a small proportion of those infected, predominantly affecting children in eastern and southern Asia. Annual JE incidence estimates range from 50,000-175,000, with 25%-30% of cases resulting in mortality. It is estimated that 3 billion people live in countries in which JEV is endemic. The virus exists in an enzootic transmission cycle, with mosquitoes transmitting JEV between birds as reservoir hosts and pigs as amplifying hosts. Zoonotic infection occurs as a result of spillover events from the main transmission cycle. The reservoir avian hosts include cattle egrets, pond herons, and other species of water birds belonging to the family Ardeidae. Irrigated rice fields provide an ideal breeding ground for mosquitoes and attract migratory birds, maintaining the transmission of JEV. Although multiple vaccines have been developed for JEV, they are expensive and require multiple doses to maintain efficacy and immunity. As humans are a "dead-end" host for the virus, vaccination of the human population is unlikely to result in eradication. Therefore, vector control of the principal mosquito vector, Culex tritaeniorhynchus, represents a more promising strategy for reducing transmission. Current vector control strategies include intermittent irrigation of rice fields and space spraying of insecticides during outbreaks. However, Cx. Tritaeniorhynchus is subject to heavy exposure to pesticides in rice fields, and as a result, insecticide resistance has developed. In recent years, significant advancements have been made in the potential use of the bacterial endosymbiont Wolbachia for mosquito biocontrol. The successful transinfection of Wolbachia strains from Drosophila flies to Aedes (Stegomyia mosquitoes has resulted in the generation of "dengue-refractory" mosquito