Science.gov

Sample records for aegypti asociado con

  1. Análisis del espectro infrarrojo del polvo interestelar asociado con cúmulos globulares y de su evolución temporal

    NASA Astrophysics Data System (ADS)

    Pellizza, L. J.; Forte, J. C.; Carpintero, D.

    El trabajo que se presenta investiga la dinámica de las partículas de polvo interestelar eyectadas por estrellas gigantes rojas en un cúmulo globular utilizando simulaciones numéricas de su interacción con el campo gravitatorio y con la radiación electromagnética de las estrellas. Se pretende con ello determinar la distribución espacial de ese material como una función del tiempo en un sistema similar a NGC 104 (47 Tuc). A partir de la distribución espacial resultante se obtuvo el espectro infrarrojo integrado el cual sugiere que el máximo contraste con la radiación estelar ocurre en longitudes de onda cercanas a 300 μm y que decrece rápidamente hacia longitudes de onda menores, en las que suelen realizarse las observaciones.

  2. Microevolution of Aedes aegypti.

    PubMed

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

    2015-01-01

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

  3. Rhamnolipids: solution against Aedes aegypti?

    PubMed Central

    Silva, Vinicius L.; Lovaglio, Roberta B.; Von Zuben, Claudio J.; Contiero, Jonas

    2015-01-01

    Aedes aegypti mosquitoes are the primary transmitters of dengue fever, urban yellow fever, and chikungunya viruses. This mosquito has developed resistance to the insecticides currently used to control their populations. These chemical insecticides are harmful to the environment and can have negative effects on human health. Rhamnolipids are environmentally compatible biological surfactants, but their insecticidal activity has not been extensively studied. The present study evaluated the potential larvicidal, insecticidal, and repellent activities of rhamnolipids against A. aegypti. At concentrations of 800, 900, and 1000 mg/L, rhamnolipids eliminated all mosquito larvae in 18 h and killed 100% of adults at 1000 mg/L. According to the results it may be conclude that rhamnolipids should be applied to control larvae and mosquitos besides present the repellency activity against A. aegypti. PMID:25762986

  4. Neuropeptidomics of the Mosquito Aedes Aegypti

    DTIC Science & Technology

    2010-01-01

    and PK in different ganglia, differential posttranslational pro- cessing of CAPA-PVK-2 in Ae. aegypti tissues was observed. The N-terminally blocked...secretory cells (X cells) is separate and posterior to the CC, and axons from these cells extend to the CC. In female An. gambiae and Ae. aegypti , these...Expression of a gene encoding AKH-2 was characterized in Ae. aegypti .19 Native AKH-2 was resolved by HPLC from head extracts of female An. gambiae in

  5. Workbook on Identification of Aedes Aegypti Larvae.

    ERIC Educational Resources Information Center

    Pratt, Harry D.; And Others

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

  6. Global genetic diversity of Aedes aegypti.

    PubMed

    Gloria-Soria, Andrea; Ayala, Diego; Bheecarry, Ambicadutt; Calderon-Arguedas, Olger; Chadee, Dave D; Chiappero, Marina; Coetzee, Maureen; Elahee, Khouaildi Bin; Fernandez-Salas, Ildefonso; Kamal, Hany A; Kamgang, Basile; Khater, Emad I M; Kramer, Laura D; Kramer, Vicki; Lopez-Solis, Alma; Lutomiah, Joel; Martins, Ademir; Micieli, Maria Victoria; Paupy, Christophe; Ponlawat, Alongkot; Rahola, Nil; Rasheed, Syed Basit; Richardson, Joshua B; Saleh, Amag A; Sanchez-Casas, Rosa Maria; Seixas, Gonçalo; Sousa, Carla A; Tabachnick, Walter J; Troyo, Adriana; Powell, Jeffrey R

    2016-11-01

    Mosquitoes, especially Aedes aegypti, are becoming important models for studying invasion biology. We characterized genetic variation at 12 microsatellite loci in 79 populations of Ae. aegypti from 30 countries in six continents, and used them to infer historical and modern patterns of invasion. Our results support the two subspecies Ae. aegypti formosus and Ae. aegypti aegypti as genetically distinct units. Ae. aegypti aegypti populations outside Africa are derived from ancestral African populations and are monophyletic. The two subspecies co-occur in both East Africa (Kenya) and West Africa (Senegal). In rural/forest settings (Rabai District of Kenya), the two subspecies remain genetically distinct, whereas in urban settings, they introgress freely. Populations outside Africa are highly genetically structured likely due to a combination of recent founder effects, discrete discontinuous habitats and low migration rates. Ancestral populations in sub-Saharan Africa are less genetically structured, as are the populations in Asia. Introduction of Ae. aegypti to the New World coinciding with trans-Atlantic shipping in the 16th to 18th centuries was followed by its introduction to Asia in the late 19th century from the New World or from now extinct populations in the Mediterranean Basin. Aedes mascarensis is a genetically distinct sister species to Ae. aegypti s.l. This study provides a reference database of genetic diversity that can be used to determine the likely origin of new introductions that occur regularly for this invasive species. The genetic uniqueness of many populations and regions has important implications for attempts to control Ae. aegypti, especially for the methods using genetic modification of populations.

  7. [Recommendations for the surveillance of Aedes aegypti].

    PubMed

    Barrera, Roberto

    2016-09-01

    Diseases caused by arboviruses transmitted by Aedes aegypti, such as dengue, chikungunya and Zika, continue to rise in annual incidence and geographic expansion. A key limitation for achieving control of A. aegypti has been the lack of effective tools for monitoring its population, and thus determine what control measures actually work. Surveillance of A. aegypti has been based mainly on immature indexes, but they bear little relation to the number of mosquito females, which are the ones capable of transmitting the viruses. The recent development of sampling techniques for adults of this vector species promises to facilitate surveillance and control activities. In this review, we present the various monitoring techniques for this mosquito, along with a discussion of their usefulness, and recommendations for improved entomological surveillance.

  8. First report of Stegomyia aegypti (= Aedes aegypti) in Mexico City, Mexico.

    PubMed

    Kuri-Morales, P; Correa-Morales, F; González-Acosta, C; Sánchez-Tejeda, G; Dávalos-Becerril, E; Fernanda Juárez-Franco, M; Díaz-Quiñonez, A; Huerta-Jimenéz, H; Mejía-Guevara, M D; Moreno-García, M; González-Roldán, J F

    2017-01-20

    Stegomyia aegypti (= Aedes aegypti) (Diptera: Culicidae) is a species of mosquito that is currently widespread in Mexico. Historically, the mosquito has been distributed across most tropical and subtropical areas lower than 1700 m a.s.l. Currently, populations that are found at higher altitudes in regions with cold and dry climates suggest that these conditions do not limit the colonization and population growth of S. aegypti. During a survey of mosquitoes in September 2015, larvae of S. aegypti mosquitoes were found in two different localities in Mexico City, which is located at about 2250 m a.s.l. Mexico City is the most populous city in Mexico and has inefficient drainage and water supply systems. These factors may result in the provision of numerous larval breeding sites. Mosquito monitoring and surveillance are now priorities for the city.

  9. Neuropeptidomics of the mosquito Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    PubMed

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

    2013-12-01

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

  11. Burchellin: study of bioactivity against Aedes aegypti

    PubMed Central

    2014-01-01

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

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

    PubMed

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

    2001-07-01

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

  13. Desiccation resistance in Aedes aegypti and Aedes albopictus eggs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Causative influences that impact the separation of Aedes aegypti and Aedes albopictus populations in different geographic areas were determined. The eggs of Ae. albopictus and Ae. aegypti collected from McAllen and Brownsville, Texas, and laboratory populations of these two species were subjected t...

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

    PubMed

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

    2013-09-01

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

  15. Aedes aegypti in Córdoba Province, Argentina.

    PubMed

    Avilés, G; Cecchini, R; Harrington, M E; Cichero, J; Asis, R; Rios, C

    1997-09-01

    In 1955, the area infested by Aedes aegypti in Argentina was estimated as 1,500,000 km2; and in 1963, the species was considered to be eradicated from Argentina. In 1995, the Argentine Ministry of Health reported reinfestation by Ae. aegypti. During 1994-95, the Ministry of Health of Córdoba Province, Zoonosis Department, established a surveillance system for Ae. aegypti in Córdoba Province, Argentina. This report is a summary of results obtained thus far. In total, 74 localities in Córdoba Province were sampled during August 1994-April 1996, resulting in 5 positives (6.7%): Villa María city, Villa Nueva, and Córdoba city in 1995, and Juarez Celman and Jesús María in 1996. In Villa María and Villa Nueva, Ae. aegypti was present until June 1995 (autumn) and reappeared in December 1995. In Córdoba city, Ae. aegypti was eliminated from the only positive house in May 1995, but it reappeared in March 1996. Reappearance of Ae. aegypti in this temperate area in early summer may have been due to the survival of individuals during winter and not to reintroduction during summertime. The last previous active surveillance for Ae. aegypti in Córdoba Province was carried out more than 30 years ago.

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

    PubMed

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

    2009-12-01

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

  17. Aedes aegypti resistance to temephos in Argentina.

    PubMed

    Seccacini, Emilia; Lucia, Alejandro; Zerba, Eduardo; Licastro, Susana; Masuh, Hector

    2008-12-01

    Monitoring of resistance of Aedes aegypti to temephos was implemented in the provinces of Formosa and Misiones, Argentina, as a response to the need to improve the vigilance for the dengue vector in areas of high risk of dengue. Eggs collected in each locality were reared, and susceptibility to temephos was assayed using larval bioassays. A weak decrease in susceptibility of larvae to temephos was observed in Clorinda and Puerto Iguazú, indicating an incipient resistance with a resistance ratio of 3. No control failures have been observed yet, and this program should allow the early detection of a real problem in our country.

  18. New Records of Aedes aegypti In Southern Oklahoma, 2016.

    PubMed

    Bradt, David L; Bradley, Kristy K; Hoback, W Wyatt; Noden, Bruce H

    2017-03-01

    Aedes aegypti is an important subtropical vector species and is predicted to have a limited year-round distribution in the southern United States. Collection of the species has not been officially verified in Oklahoma since 1940. Adult mosquitoes were collected in 42 sites across 7 different cities in Oklahoma using 3 different mosquito traps between May and September 2016. Between July and September 2016, 88 Ae. aegypti adults were collected at 18 different sites in 4 different cities across southern Oklahoma. Centers for Disease Control and Prevention mini light traps baited with CO2 attracted the highest numbers of Ae. aegypti individuals compared to Biogents (BG)-Sentinel(®) traps baited with Biogents (BG)-lure and octenol and Centers for Disease Control and Prevention gravid traps baited with Bermuda grass-infused water. The discovery of Ae. aegypti mosquitoes within urban/exurban areas in Oklahoma is important from an ecological as well as a public health perspective.

  19. Aedes aegypti D7 Saliva Protein Inhibits Dengue Virus Infection

    PubMed Central

    Conway, Michael J.; Londono-Renteria, Berlin; Troupin, Andrea; Watson, Alan M.; Klimstra, William B.; Fikrig, Erol; Colpitts, Tonya M.

    2016-01-01

    Aedes aegypti is the primary vector of several medically relevant arboviruses including dengue virus (DENV) types 1–4. Ae. aegypti transmits DENV by inoculating virus-infected saliva into host skin during probing and feeding. Ae. aegypti saliva contains over one hundred unique proteins and these proteins have diverse functions, including facilitating blood feeding. Previously, we showed that Ae. aegypti salivary gland extracts (SGEs) enhanced dissemination of DENV to draining lymph nodes. In contrast, HPLC-fractionation revealed that some SGE components inhibited infection. Here, we show that D7 proteins are enriched in HPLC fractions that are inhibitory to DENV infection, and that recombinant D7 protein can inhibit DENV infection in vitro and in vivo. Further, binding assays indicate that D7 protein can directly interact with DENV virions and recombinant DENV envelope protein. These data reveal a novel role for D7 proteins, which inhibits arbovirus transmission to vertebrates through a direct interaction with virions. PMID:27632170

  20. Larval nutritional stress affects vector immune traits in adult yellow fever mosquito Aedes aegypti (Stegomyia aegypti).

    PubMed

    Telang, A; Qayum, A A; Parker, A; Sacchetta, B R; Byrnes, G R

    2012-09-01

    We report key physiological traits that link larval nutritional experience to adult immune status in the yellow fever mosquito Aedes aegypti L. (Stegomyia aegypti) (Diptera: Culicidae). Many lines of defence make up the innate immune system of mosquitoes. Among defences, the epithelium-lined midgut is the first barrier, circulating haemocytes are cellular components of innate immunity and, when triggered, the Toll and Imd pathways signal production of antimicrobial peptides (AMP) as part of humoral defences. We quantified three lines of defence in Ae. aegypti in response to larval nutritional stress, and our data show that important female immune functions are modified by the larval rearing environment. Adult midgut basal lamina thickness was not affected by larval nutrient stress as has been observed in another Aedes sp. However, nutrient stresses experienced by larvae lead to a reduced number of haemocytes in females. Transcripts of Spaetzle (upstream regulator of Toll pathway that leads to induction of AMPs) and some immune-related genes were less abundant in stressed larvae but showed increased expression in females derived from stressed larvae. Results indicate a potential for compensation by the humoral branch for a reduced cellular branch of innate immunity in adults in response to larval nutrient stress.

  1. Indoor development of Aedes aegypti in Germany, 2016

    PubMed Central

    Kampen, Helge; Jansen, Stephanie; Schmidt-Chanasit, Jonas; Walther, Doreen

    2016-01-01

    In spring 2016, a German traveller returning from Martinique cultivated imported plant offsets in her home, and accidentally bred Aedes aegypti. Thirteen adult mosquito specimens submitted for identification and the traveller were tested for Zika, dengue and chikungunya virus infections, with negative results. The detection of Ae. aegypti by the ‘Mueckenatlas’ project demonstrates the value of this passive surveillance scheme for potential public health threats posed by invasive mosquitoes in Germany. PMID:27918261

  2. Morphological and genetic variability within Aedes aegypti in Niakhar, Senegal.

    PubMed

    Paupy, Christophe; Brengues, Cécile; Ndiath, Ousmane; Toty, Céline; Hervé, Jean-Pierre; Simard, Frédéric

    2010-05-01

    Aedes aegypti (Linné, 1762) is a major vector of arboviruses such as Yellow Fever, Dengue and Chikungunya. In Africa, where the species exhibits major variations in morphology, ecology, behavior and vector competence, two subspecies have been described: a light form, named Ae. aegypti aegypti (Aaa) with highly domestic and anthropophilic habits and a cosmotropical distribution; and a dark form, referred to as Ae. aegypti formosus (Aaf), which is endemic to Africa and thrives in sylvan environments. In East Africa, both forms were described to occur in sympatry whereas only Aaf was reported from Central/West Africa. However, recent findings suggest Aaa was also common in Senegal. Here, we report on a longitudinal survey of morphological and genetic variability of Ae. aegypti sampled in the rural environment of Niakhar, Senegal. In agreement with recent findings, most of specimens we analyzed were classified as Aaa suggesting typical Aaf was scarce in the studied area. Among Aaa, significant temporal variations in abdominal pale scales pattern were detected. Depending on the season and the nature of larval breeding places, the specimens (particularly females) tend to segregate in two main morphological groups. Microsatellite-based estimates of genetic differentiation did not provide any clear evidence that the two groups were genetically distinct. Overall, these results improve our understanding of the diversity of Ae. aegypti in West Africa, where data are crucially lacking.

  3. Estudio multifrecuencia del flujo bipolar-molecular asociado con la proto-estrella VLA 1623

    NASA Astrophysics Data System (ADS)

    Artur de la Villarmois, E.; Merlo, D. C.; Gómez, M.

    In this work; we present a multi-wavelength study of the bipolar molecular outflow associated with the VLA 1623 proto-star (age 10 yrs). We analyze images obtained by Spitzer as well as other images from the literature. We identify 32 H (2.12 m) emission knots and 25 objects predominantly emitting in the [4.5] m band; usually known as EGOs (Extended Green Objects). Seven of these emissions are new EGO candidates; five of which have 2.12 m counter-parts. We compare the morphology of the emissions at 2.12 m and [4.5] m with the bipolar molecular outflow; finding an excellent agreement. The emissions are quasi-regularly spaced. We determine a dynamical time of 194.3 yrs between consecutive knots; which agrees with the lapse of time between eruptive FU Orionis events. This suggests that events of this type experimented by the central source might be the cause of the intermittency in the detected emissions. FULL TEXT IN SPANISH

  4. Effect of temperature on the population dynamics of Aedes aegypti

    NASA Astrophysics Data System (ADS)

    Yusoff, Nuraini; Tokachil, Mohd Najir

    2015-10-01

    Aedes aegypti is one of the main vectors in the transmission of dengue fever. Its abundance may cause the spread of the disease to be more intense. In the study of its biological life cycle, temperature was found to increase the development rate of each stage of this species and thus, accelerate the process of the development from egg to adult. In this paper, a Lefkovitch matrix model will be used to study the stage-structured population dynamics of Aedes aegypti. In constructing the transition matrix, temperature will be taken into account. As a case study, temperature recorded at the Subang Meteorological Station for year 2006 until 2010 will be used. Population dynamics of Aedes aegypti at maximum, average and minimum temperature for each year will be simulated and compared. It is expected that the higher the temperature, the faster the mosquito will breed. The result will be compared to the number of dengue fever incidences to see their relationship.

  5. Mathematical model of temephos resistance in Aedes aegypti mosquito population

    NASA Astrophysics Data System (ADS)

    Aldila, D.; Nuraini, N.; Soewono, E.; Supriatna, A. K.

    2014-03-01

    Aedes aegypti is the main vector of dengue disease in many tropical and sub-tropical countries. Dengue became major public concern in these countries due to the unavailability of vaccine or drugs for dengue disease in the market. Hence, the only way to control the spread of DF and DHF is by controlling the vectors carrying the disease, for instance with fumigation, temephos or genetic manipulation. Many previous studies conclude that Aedes aegypti may develop resistance to many kind of insecticide, including temephos. Mathematical model for transmission of temephos resistance in Aedes aegypti population is discussed in this paper. Nontrivial equilibrium point of the system and the corresponding existence are shown analytically. The model analysis have shown epidemiological trends condition that permits the coexistence of nontrivial equilibrium is given analytically. Numerical results are given to show parameter sensitivity and some cases of worsening effect values for illustrating possible conditions in the field.

  6. The global compendium of Aedes aegypti and Ae. albopictus occurrence

    NASA Astrophysics Data System (ADS)

    Kraemer, Moritz U. G.; Sinka, Marianne E.; Duda, Kirsten A.; Mylne, Adrian; Shearer, Freya M.; Brady, Oliver J.; Messina, Jane P.; Barker, Christopher M.; Moore, Chester G.; Carvalho, Roberta G.; Coelho, Giovanini E.; van Bortel, Wim; Hendrickx, Guy; Schaffner, Francis; Wint, G. R. William; Elyazar, Iqbal R. F.; Teng, Hwa-Jen; Hay, Simon I.

    2015-07-01

    Aedes aegypti and Ae. albopictus are the main vectors transmitting dengue and chikungunya viruses. Despite being pathogens of global public health importance, knowledge of their vectors’ global distribution remains patchy and sparse. A global geographic database of known occurrences of Ae. aegypti and Ae. albopictus between 1960 and 2014 was compiled. Herein we present the database, which comprises occurrence data linked to point or polygon locations, derived from peer-reviewed literature and unpublished studies including national entomological surveys and expert networks. We describe all data collection processes, as well as geo-positioning methods, database management and quality-control procedures. This is the first comprehensive global database of Ae. aegypti and Ae. albopictus occurrence, consisting of 19,930 and 22,137 geo-positioned occurrence records respectively. Both datasets can be used for a variety of mapping and spatial analyses of the vectors and, by inference, the diseases they transmit.

  7. Stage-Structured Population Dynamics of AEDES AEGYPTI

    NASA Astrophysics Data System (ADS)

    Yusoff, Nuraini; Budin, Harun; Ismail, Salemah

    Aedes aegypti is the main vector in the transmission of dengue fever, a vector-borne disease affecting world population living in tropical and sub-tropical countries. Better understanding of the dynamics of its population growth will help in the efforts of controlling the spread of this disease. In looking at the population dynamics of Aedes aegypti, this paper explored the stage-structured modeling of the population growth of the mosquito using the matrix population model. The life cycle of the mosquito was divided into five stages: eggs, larvae, pupae, adult1 and adult2. Developmental rates were obtained for the average Malaysian temperature and these were used in constructing the transition matrix for the matrix model. The model, which was based only on temperature, projected that the population of Aedes aegypti will blow up with time, which is not realistic. For further work, other factors need to be taken into account to obtain a more realistic result.

  8. Larvicidal activity of Tagetes erecta against Aedes aegypti.

    PubMed

    Marques, Márcia M M; Morais, Selene M; Vieira, Icaro G P; Vieira, Mariano G S; Raquel, Ana; Silva, A; De Almeida, Raimundo Rafael; Guedes, Maria Izabel F

    2011-06-01

    The aim of this study was to evaluate the activity of essential oil from Tagetes erecta against 3rd instars of Aedes aegypti and to determine the amounts of larvicidal thiophenes in all plant tissues. The oil obtained by steam distillation and analyzed by gas chromatography/mass spectrometry showed 14 compounds. The main compounds were piperitone (45.72%), D-limonene (9.67%), and piperitenone (5.89%). The essential oil was active against larvae of Ae. aegypti, with LC50 of 79.78 microg/ml and LC90 of 100.84 microg/ml. The larvicidal thiophene contents were higher in the roots and flowers as demonstrated by high-performance liquid chromatography analysis. Thus, T. erecta constitutes a good source of varied compounds showing larvicidal activity against Ae. aegypti.

  9. Experimental transmission of Mayaro virus by Aedes aegypti.

    PubMed

    Long, Kanya C; Ziegler, Sarah A; Thangamani, Saravanan; Hausser, Nicole L; Kochel, Tadeusz J; Higgs, Stephen; Tesh, Robert B

    2011-10-01

    Outbreaks of Mayaro fever have been associated with a sylvatic cycle of Mayaro virus (MAYV) transmission in South America. To evaluate the potential for a common urban mosquito to transmit MAYV, laboratory vector competence studies were performed with Aedes aegypti from Iquitos, Peru. Oral infection in Ae. aegypti ranged from 0% (0/31) to 84% (31/37), with blood meal virus titers between 3.4 log(10) and 7.3 log(10) plaque-forming units (PFU)/mL. Transmission of MAYV by 70% (21/30) of infected mosquitoes was shown by saliva collection and exposure to suckling mice. Amount of viral RNA in febrile humans, determined by real-time polymerase chain reaction, ranged from 2.7 to 5.3 log(10) PFU equivalents/mL. Oral susceptibility of Ae. aegypti to MAYV at titers encountered in viremic humans may limit opportunities to initiate an urban cycle; however, transmission of MAYV by Ae. aegypti shows the vector competence of this species and suggests potential for urban transmission.

  10. Pyrethroid resistance is widespread among Florida populations of Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aedes aegypti is an efficient vector of a number of diseases that affect man and is of increasing concern because of the reemergence of dengue and recent identification of locally acquired chikungunya in Florida. Pesticide resistance in this species has been demonstrated in several neighboring coun...

  11. Argonaute 2 Suppresses Japanese Encephalitis Virus Infection in Aedes aegypti.

    PubMed

    Sasaki, Toshinori; Kuwata, Ryusei; Hoshino, Keita; Isawa, Haruhiko; Sawabe, Kyoko; Kobayashi, Mutsuo

    2017-01-24

    There are three main innate immune mechanisms against viruses in mosquitoes. Infection with the flavivirus dengue virus is controlled by RNA interference (RNAi) and the JAK-STAT and Toll signaling pathways. This study showed that another flavivirus, Japanese encephalitis virus (JEV), did not invade the salivary glands of Aedes aegypti and that this may be a result of the innate immune resistance to the virus. Argonaute 2 (Ago2) plays a critical role in the RNAi pathway. To understand the mechanism of JEV resistance, we focused on Ago2 as a possible target of JEV. Here, we show that the expression of MyD88 (a mediator of Toll signaling) and Ago2 mRNAs was induced by JEV in the salivary glands of Ae. aegypti mosquitoes and that Ago2, JAK, and domeless (DOME) mRNAs were induced by JEV in the bodies of Ae. aegypti mosquitoes. Double-stranded (ds) Ago2 RNA enhanced JEV infection, and the virus was detected in salivary glands by immunofluorescence assay. In contrast, MyD88 dsRNA had no effect on JEV infection. These data suggest that Ago2 plays a crucial role in mediating the innate immune response of Ae. aegypti to JEV in a manner similar to that employed by dengue virus.

  12. A review on symmetries for certain Aedes aegypti models

    NASA Astrophysics Data System (ADS)

    Freire, Igor Leite; Torrisi, Mariano

    2015-04-01

    We summarize our results related with mathematical modeling of Aedes aegypti and its Lie symmetries. Moreover, some explicit, group-invariant solutions are also shown. Weak equivalence transformations of more general reaction diffusion systems are also considered. New classes of solutions are obtained.

  13. Integrated proteomic and transcriptomic analysis of the Aedes aegypti eggshell

    PubMed Central

    2014-01-01

    Background Mosquito eggshells show remarkable diversity in physical properties and structure consistent with adaptations to the wide variety of environments exploited by these insects. We applied proteomic, transcriptomic, and hybridization in situ techniques to identify gene products and pathways that participate in the assembly of the Aedes aegypti eggshell. Aedes aegypti population density is low during cold and dry seasons and increases immediately after rainfall. The survival of embryos through unfavorable periods is a key factor in the persistence of their populations. The work described here supports integrated vector control approaches that target eggshell formation and result in Ae. aegypti drought-intolerant phenotypes for public health initiatives directed to reduce mosquito-borne diseases. Results A total of 130 proteins were identified from the combined mass spectrometric analyses of eggshell preparations. Conclusions Classification of proteins according to their known and putative functions revealed the complexity of the eggshell structure. Three novel Ae. aegypti vitelline membrane proteins were discovered. Odorant-binding and cysteine-rich proteins that may be structural components of the eggshell were identified. Enzymes with peroxidase, laccase and phenoloxidase activities also were identified, and their likely involvements in cross-linking reactions that stabilize the eggshell structure are discussed. PMID:24707823

  14. Functional genetic characterization of salivary gland development in Aedes aegypti

    PubMed Central

    2013-01-01

    Background Despite the devastating global impact of mosquito-borne illnesses on human health, very little is known about mosquito developmental biology. In this investigation, functional genetic analysis of embryonic salivary gland development was performed in Aedes aegypti, the dengue and yellow fever vector and an emerging model for vector mosquito development. Although embryonic salivary gland development has been well studied in Drosophila melanogaster, little is known about this process in mosquitoes or other arthropods. Results Mosquitoes possess orthologs of many genes that regulate Drosophila melanogaster embryonic salivary gland development. The expression patterns of a large subset of these genes were assessed during Ae. aegypti development. These studies identified a set of molecular genetic markers for the developing mosquito salivary gland. Analysis of marker expression allowed for tracking of the progression of Ae. aegypti salivary gland development in embryos. In Drosophila, the salivary glands develop from placodes located in the ventral neuroectoderm. However, in Ae. aegypti, salivary marker genes are not expressed in placode-like patterns in the ventral neuroectoderm. Instead, marker gene expression is detected in salivary gland rudiments adjacent to the proventriculus. These observations highlighted the need for functional genetic characterization of mosquito salivary gland development. An siRNA- mediated knockdown strategy was therefore employed to investigate the role of one of the marker genes, cyclic-AMP response element binding protein A (Aae crebA), during Ae. aegypti salivary gland development. These experiments revealed that Aae crebA encodes a key transcriptional regulator of the secretory pathway in the developing Ae. aegypti salivary gland. Conclusions The results of this investigation indicated that the initiation of salivary gland development in Ae. aegypti significantly differs from that of D. melanogaster. Despite these differences

  15. Experience- and age-mediated oviposition behaviour in the yellow fever mosquito Stegomyia aegypti (=Aedes aegypti).

    PubMed

    Ruktanonchai, N W; Lounibos, L P; Smith, D L; Allan, S A

    2015-09-01

    In repeated behaviours such as those of feeding and reproduction, past experiences can inform future behaviour. By altering their behaviour in response to environmental stimuli, insects in highly variable landscapes can tailor their behaviour to their particular environment. In particular, female mosquitoes may benefit from plasticity in their choice of egg-laying site as these sites are often temporally variable and clustered. The opportunity to adapt egg-laying behaviour to past experience also exists for mosquito populations as females typically lay eggs multiple times throughout their lives. Whether experience and age affect egg-laying (or oviposition) behaviour in the mosquito Stegomyia aegypti (=Aedes aegypti) (Diptera: Culicidae) was assessed using a wind tunnel. Initially, gravid mosquitoes were provided with a cup containing either repellent or well water. After ovipositing in these cups, the mosquitoes were blood-fed and introduced into a wind tunnel. In this wind tunnel, an oviposition cup containing repellent was placed in the immediate vicinity of the gravid mosquitoes. A cup containing well water was placed at the opposite end of the tunnel so that if the females flew across the chamber, they encountered the well water cup, in which they readily laid eggs. Mosquitoes previously exposed to repellent cups became significantly more likely to later lay eggs in repellent cups, suggesting that previous experience with suboptimal oviposition sites informs mosquitoes of the characteristics of nearby oviposition sites. These results provide further evidence that mosquitoes modify behaviour in response to environmental information and are demonstrated in a vector species in which behavioural plasticity may be ecologically and epidemiologically meaningful.

  16. Effect of Temperature on the Vector Efficiency of Aedes aegypti for Dengue 2 Virus

    DTIC Science & Technology

    1986-06-26

    VECTOR EFFICIENCY OF AEDES AEGYPTI FOR DENGUE 2 VIRUS DOUGLAS M. WATTS,* DONALD S. BURKE,** BRUCE A. HARRISON,-/- RICHARD E. WHITMIRE,* AND ANANDA...the ability of Aedes aegypti to transmit dengue (DEN) 2 virus to rhesus monkeys was assessed as a possible explanation for the seasonal variation...in the incidence of dengue hemorrhagic fever in Bangkok, Thailand. In two laboratory experiments, a Bangkok strain of Ae. aegypti was allowed to feed

  17. Comparative efficacy of existing surveillance tools for Aedes aegypti in Western Kenya.

    PubMed

    Yalwala, Sancto; Clark, Jeffrey; Oullo, David; Ngonga, Daniel; Abuom, David; Wanja, Elizabeth; Bast, Joshua

    2015-12-01

    All traditional surveillance techniques for Aedes aegypti have been developed for the cosmopolitan domestic subspecies Ae. aegypti aegypti, and not the sylvatic subspecies, Ae. aegypti formosus. The predominant form in Western Kenya is Ae. aegypti formosus that is rarely associated with human habitations but is linked to transmission of sylvatic dengue virus strains. We compared five surveillance methods for their effectiveness in sampling Ae. aegypti formosus with the goal of determining a sustainable surveillance strategy in Kenya. The methods included larval and pupal surveys, oviposition trapping, BG-Sentinel trapping, resting boxes, and backpack aspirations. Larval and pupal surveys collected the highest number of Ae. aegypti formosus (51.3%), followed by oviposition traps (45.7%), BG-Sentinel traps (3.0%), and zero collected with either backpack aspiration or resting box collections. No Ae. aegypti formosus larvae or pupae were found indoors. The results indicate that oviposition traps and outdoor larval and pupal surveys were better surveillance methods for Ae. aegypti formosus in Western Kenya.

  18. Implications of saline concentrations for the performance and competitive interactions of the mosquitoes Aedes aegypti (Stegomyia aegypti) and Aedes albopictus (Stegomyia albopictus).

    PubMed

    Yee, D A; Himel, E; Reiskind, M H; Vamosi, S M

    2014-03-01

    Aedes albopictus (Stegomyia albopictus) (Diptera: Culicidae) has probably supplanted Aedes aegypti (Stegomyia aegypti) throughout most of its historical range in the U.S.A., although Ae. aegypti still exists in large coastal cities in southern Florida. We measured salt concentrations in field containers along an axis perpendicular to the coast and examined intraspecific outcomes in these species under different salt concentrations in a factorial study using varying intra- and interspecific densities in different conditions of salinity to order to determine if salt could mitigate the documented competitive superiority of Ae. albopictus. Salt in field containers declined away from the coast, with maximal values similar to our lower salt concentrations. Egg hatching and short-term survival of pupae and late instars were not affected by salt concentrations; survival of early instars of both species decreased at higher concentrations. In high salt conditions, Ae. aegypti achieved higher survival. In the longterm experiment, both species displayed longer development times. Salt did not affect interactions for either species; Ae. aegypti survived in the highest salt conditions, regardless of density. The tolerance of Ae. aegypti to high salt concentrations may allow it to use coastal containers, although because salt did not mediate interspecific interactions between Ae. aegypti and Ae. albopictus, the ultimate effects of salt on the coexistence of these species or exclusion of either species remain unknown.

  19. Targeted genome editing in Aedes aegypti using TALENs.

    PubMed

    Aryan, Azadeh; Myles, Kevin M; Adelman, Zach N

    2014-08-15

    The Culicine mosquito, Aedes aegypti, is both a major vector of arthropod-borne viruses (arboviruses) and a genetic model organism for arbovirus transmission. TALE nucleases (TALENs), a group of artificial enzymes capable of generating site-specific DNA lesions, consist of a non-specific FokI endonuclease cleavage domain fused to an engineered DNA binding domain specific to a target site. While TALENs have become an important tool for targeted gene disruption in a variety of organisms, application to the mosquito genome is a new approach. We recently described the use of TALENs to perform heritable genetic disruptions in A. aegypti. Here, we provide detailed methods that will allow other research laboratories to capitalize on the potential of this technology for understanding mosquito gene function. We describe target site selection, transient embryo-based assays to rapidly assess TALEN activity, embryonic microinjection and downstream screening steps to identify target site mutations.

  20. Evidence of Polyandry for Aedes aegypti in Semifield Enclosures

    PubMed Central

    Helinski, Michelle E. H.; Valerio, Laura; Facchinelli, Luca; Scott, Thomas W.; Ramsey, Janine; Harrington, Laura C.

    2012-01-01

    Female Aedes aegypti are assumed to be primarily monandrous (i.e., mate only once in their lifetime), but true estimates of mating frequency have not been determined outside the laboratory. To assess polyandry in Ae. aegypti with first-generation progeny from wild mosquitoes, stable isotope semen-labeled males (15N or 13C) were allowed to mate with unlabeled females in semifield enclosures (22.5 m3) in a dengue-endemic area in southern Mexico. On average, 14% of females were positive for both labels, indicating that they received semen from more than one male. Our results provide evidence of a small but potentially significant rate of multiple mating within a 48-hour period and provide an approach for future open-field studies of polyandry in this species. Polyandry has implications for understanding mosquito ecology, evolution, and reproductive behavior as well as genetic strategies for mosquito control. PMID:22492148

  1. Identification of germline transcriptional regulatory elements in Aedes aegypti

    NASA Astrophysics Data System (ADS)

    Akbari, Omar S.; Papathanos, Philippos A.; Sandler, Jeremy E.; Kennedy, Katie; Hay, Bruce A.

    2014-02-01

    The mosquito Aedes aegypti is the principal vector for the yellow fever and dengue viruses, and is also responsible for recent outbreaks of the alphavirus chikungunya. Vector control strategies utilizing engineered gene drive systems are being developed as a means of replacing wild, pathogen transmitting mosquitoes with individuals refractory to disease transmission, or bringing about population suppression. Several of these systems, including Medea, UDMEL, and site-specific nucleases, which can be used to drive genes into populations or bring about population suppression, utilize transcriptional regulatory elements that drive germline-specific expression. Here we report the identification of multiple regulatory elements able to drive gene expression specifically in the female germline, or in the male and female germline, in the mosquito Aedes aegypti. These elements can also be used as tools with which to probe the roles of specific genes in germline function and in the early embryo, through overexpression or RNA interference.

  2. Sodium Channel Mutations and Pyrethroid Resistance in Aedes aegypti

    PubMed Central

    Du, Yuzhe; Nomura, Yoshiko; Zhorov, Boris S.; Dong, Ke

    2016-01-01

    Pyrethroid insecticides are widely used to control insect pests and human disease vectors. Voltage-gated sodium channels are the primary targets of pyrethroid insecticides. Mutations in the sodium channel have been shown to be responsible for pyrethroid resistance, known as knockdown resistance (kdr), in various insects including mosquitoes. In Aedes aegypti mosquitoes, the principal urban vectors of dengue, zika, and yellow fever viruses, multiple single nucleotide polymorphisms in the sodium channel gene have been found in pyrethroid-resistant populations and some of them have been functionally confirmed to be responsible for kdr in an in vitro expression system, Xenopus oocytes. This mini-review aims to provide an update on the identification and functional characterization of pyrethroid resistance-associated sodium channel mutations from Aedes aegypti. The collection of kdr mutations not only helped us develop molecular markers for resistance monitoring, but also provided valuable information for computational molecular modeling of pyrethroid receptor sites on the sodium channel. PMID:27809228

  3. Linkage map for Aedes aegypti using restriction fragment length polymorphisms.

    PubMed

    Severson, D W; Mori, A; Zhang, Y; Christensen, B M

    1993-01-01

    We report construction of a genetic linkage map for the mosquito, Aedes aegypti, based on restriction fragment length polymorphisms (RFLPs). The map consists of 50 DNA markers that identify 53 loci covering 134 map units across three linkage groups. Determination of linkage associations between RFLP markers and several mutant marker loci allowed for partial integration of the RFLP markers with an existing classical genetic linkage map for A. aegypti. The RFLP markers include 42 random cDNA clones, three random genomic DNA clones, and five cDNA clones of known genes. We discuss the influence of autosomal sex determination, characteristic of culicine mosquitoes, in relation to its observed influence on segregation ratios. This has important ramifications for future efforts to identify quantitative trait loci associated with the ability of these mosquitoes to transmit various pathogens and parasites to man and other animals.

  4. Genome sequence of Aedes aegypti, a major arbovirus vector.

    PubMed

    Nene, Vishvanath; Wortman, Jennifer R; Lawson, Daniel; Haas, Brian; Kodira, Chinnappa; Tu, Zhijian Jake; Loftus, Brendan; Xi, Zhiyong; Megy, Karyn; Grabherr, Manfred; Ren, Quinghu; Zdobnov, Evgeny M; Lobo, Neil F; Campbell, Kathryn S; Brown, Susan E; Bonaldo, Maria F; Zhu, Jingsong; Sinkins, Steven P; Hogenkamp, David G; Amedeo, Paolo; Arensburger, Peter; Atkinson, Peter W; Bidwell, Shelby; Biedler, Jim; Birney, Ewan; Bruggner, Robert V; Costas, Javier; Coy, Monique R; Crabtree, Jonathan; Crawford, Matt; Debruyn, Becky; Decaprio, David; Eiglmeier, Karin; Eisenstadt, Eric; El-Dorry, Hamza; Gelbart, William M; Gomes, Suely L; Hammond, Martin; Hannick, Linda I; Hogan, James R; Holmes, Michael H; Jaffe, David; Johnston, J Spencer; Kennedy, Ryan C; Koo, Hean; Kravitz, Saul; Kriventseva, Evgenia V; Kulp, David; Labutti, Kurt; Lee, Eduardo; Li, Song; Lovin, Diane D; Mao, Chunhong; Mauceli, Evan; Menck, Carlos F M; Miller, Jason R; Montgomery, Philip; Mori, Akio; Nascimento, Ana L; Naveira, Horacio F; Nusbaum, Chad; O'leary, Sinéad; Orvis, Joshua; Pertea, Mihaela; Quesneville, Hadi; Reidenbach, Kyanne R; Rogers, Yu-Hui; Roth, Charles W; Schneider, Jennifer R; Schatz, Michael; Shumway, Martin; Stanke, Mario; Stinson, Eric O; Tubio, Jose M C; Vanzee, Janice P; Verjovski-Almeida, Sergio; Werner, Doreen; White, Owen; Wyder, Stefan; Zeng, Qiandong; Zhao, Qi; Zhao, Yongmei; Hill, Catherine A; Raikhel, Alexander S; Soares, Marcelo B; Knudson, Dennis L; Lee, Norman H; Galagan, James; Salzberg, Steven L; Paulsen, Ian T; Dimopoulos, George; Collins, Frank H; Birren, Bruce; Fraser-Liggett, Claire M; Severson, David W

    2007-06-22

    We present a draft sequence of the genome of Aedes aegypti, the primary vector for yellow fever and dengue fever, which at approximately 1376 million base pairs is about 5 times the size of the genome of the malaria vector Anopheles gambiae. Nearly 50% of the Ae. aegypti genome consists of transposable elements. These contribute to a factor of approximately 4 to 6 increase in average gene length and in sizes of intergenic regions relative to An. gambiae and Drosophila melanogaster. Nonetheless, chromosomal synteny is generally maintained among all three insects, although conservation of orthologous gene order is higher (by a factor of approximately 2) between the mosquito species than between either of them and the fruit fly. An increase in genes encoding odorant binding, cytochrome P450, and cuticle domains relative to An. gambiae suggests that members of these protein families underpin some of the biological differences between the two mosquito species.

  5. Genetic variability in populations of Aëdes aegypti

    PubMed Central

    Craig, George B.; Vandehey, Robert C.; Hickey, William A.

    1961-01-01

    Although Aëdes aegypti shows extensive physiological, bionomic and morphological variation in different populations, the genetic basis for this variation has never been determined. Genetic plasticity influences disease transmission, resistance to control measures, and breeding behaviour. Solutions to problems of public health importance may depend upon an understanding of the present and potential degree of genetic resiliency in mosquito populations. The purpose of the work described in this paper was to demonstrate that a pattern of considerable genetic plasticity exists for A. aegypti and to indicate the range and some of the implications of this plasticity. Observations on over 30 strains of various geographical origins have revealed genetic variation with respect to sex ratio and at least 35 morphological characteristics. Balanced polymorphism is common in laboratory colonies and probably in field populations as well. Inbreeding experiments were conducted to determine the degree of heterozygosity in populations. On the average, every mosquito carried one hidden morphological mutation. PMID:13696190

  6. Variation in Aedes aegypti Mosquito Competence for Zika Virus Transmission.

    PubMed

    Roundy, Christopher M; Azar, Sasha R; Rossi, Shannan L; Huang, Jing H; Leal, Grace; Yun, Ruimei; Fernandez-Salas, Ildefonso; Vitek, Christopher J; Paploski, Igor A D; Kitron, Uriel; Ribeiro, Guilherme S; Hanley, Kathryn A; Weaver, Scott C; Vasilakis, Nikos

    2017-04-01

    To test whether Zika virus has adapted for more efficient transmission by Aedes aegypti mosquitoes, leading to recent urban outbreaks, we fed mosquitoes from Brazil, the Dominican Republic, and the United States artificial blood meals containing 1 of 3 Zika virus strains (Senegal, Cambodia, Mexico) and monitored infection, dissemination, and virus in saliva. Contrary to our hypothesis, Cambodia and Mexica strains were less infectious than the Senegal strain. Only mosquitoes from the Dominican Republic transmitted the Cambodia and Mexica strains. However, blood meals from viremic mice were more infectious than artificial blood meals of comparable doses; the Cambodia strain was not transmitted by mosquitoes from Brazil after artificial blood meals, whereas 61% transmission occurred after a murine blood meal (saliva titers up to 4 log 10 infectious units/collection). Although regional origins of vector populations and virus strain influence transmission efficiency, Ae. aegypti mosquitoes appear to be competent vectors of Zika virus in several regions of the Americas.

  7. Variation in Aedes aegypti Mosquito Competence for Zika Virus Transmission

    PubMed Central

    Roundy, Christopher M.; Azar, Sasha R.; Rossi, Shannan L.; Huang, Jing H.; Leal, Grace; Yun, Ruimei; Fernandez-Salas, Ildefonso; Vitek, Christopher J.; Paploski, Igor A.D.; Kitron, Uriel; Ribeiro, Guilherme S.; Hanley, Kathryn A.

    2017-01-01

    To test whether Zika virus has adapted for more efficient transmission by Aedes aegypti mosquitoes, leading to recent urban outbreaks, we fed mosquitoes from Brazil, the Dominican Republic, and the United States artificial blood meals containing 1 of 3 Zika virus strains (Senegal, Cambodia, Mexico) and monitored infection, dissemination, and virus in saliva. Contrary to our hypothesis, Cambodia and Mexica strains were less infectious than the Senegal strain. Only mosquitoes from the Dominican Republic transmitted the Cambodia and Mexica strains. However, blood meals from viremic mice were more infectious than artificial blood meals of comparable doses; the Cambodia strain was not transmitted by mosquitoes from Brazil after artificial blood meals, whereas 61% transmission occurred after a murine blood meal (saliva titers up to 4 log10 infectious units/collection). Although regional origins of vector populations and virus strain influence transmission efficiency, Ae. aegypti mosquitoes appear to be competent vectors of Zika virus in several regions of the Americas. PMID:28287375

  8. Aedes aegypti (L.) and Aedes albopictus (Skuse) in Singapore City

    PubMed Central

    Ho, B. C.; Chan, K. L.; Chan, Y. C.

    1971-01-01

    Fluctuations in the adult Ae. aegypti and Ae. albopictus populations and their relationship to rainfall were studied by weekly collections from a number of stations in the city. Aedes aegypti populations generally fluctuated with the rainfall, with multiple peaks, except in the middle of the year when there was no increase in rainfall at the time of the peak in population. It is suggested that other regulating factors, in addition to rainfall, also determine the fluctuations of this species. Aedes albopictus also fluctuated, with three peaks in a year, and these bore a close relationship to rainfall. In one area, both larvae and adults of Ae. albopictus were studied simultaneously. The larval populations were investigated by exposing tin cans in the field. The population peaks of larvae were found to precede those of adults by almost exactly 2 months. It is suggested that each adult population peak represents the cumulative effect of more than one generation of mosquitos. PMID:5316747

  9. EFFICACY OF THAI NEEM OIL AGAINST AEDES AEGYPTI (L.) LARVAE.

    PubMed

    Silapanuntakul, Suthep; Keanjoom, Romnalin; Pandii, Wongdyan; Boonchuen, Supawadee; Sombatsiri, Kwanchai

    2016-05-01

    Trees with larvicidal activity may be found in Thailand. We conducted this study to evaluate the efficacy and length of efficacy of Thai neem (Azadirachta siamensis) oil emulsion and an alginate bead of Thai neem oil formulation against early fourth stage Aedes aegypti larvae using a dipping test. The Thai neem oil emulsion had significantly greater larvicidal activity than the alginate bead formulation at 12 to 60 hours post-exposure (p < 0.01). The Thai neem oil formulation resulted in 100% mortality among the early fourth stage Aedes aegypti larvae at 48 hours, while the alginate bead formulation resulted in 98% larval mortality at 84 hours and 100% mortality at 96 hours. The mean larval mortality using the Thai neem oil emulsion dropped to < 25% by 12 days and with the alginate beads dropped to < 25% by 15 days of exposure.

  10. Similarity solutions for systems arising from an Aedes aegypti model

    NASA Astrophysics Data System (ADS)

    Freire, Igor Leite; Torrisi, Mariano

    2014-04-01

    In a recent paper a new model for the Aedes aegypti mosquito dispersal dynamics was proposed and its Lie point symmetries were investigated. According to the carried group classification, the maximal symmetry Lie algebra of the nonlinear cases is reached whenever the advection term vanishes. In this work we analyze the family of systems obtained when the wind effects on the proposed model are neglected. Wide new classes of solutions to the systems under consideration are obtained.

  11. Intraspecific Competition and Population Dynamics of Aedes aegypti

    NASA Astrophysics Data System (ADS)

    Paixão, C. A.; Charret, I. C.; Lima, R. R.

    2012-04-01

    We report computational simulations for the evolution of the population of the dengue vector, Aedes aegypti mosquitoes. The results suggest that controlling the mosquito population, on the basis of intraspecific competition at the larval stage, can be an efficient mechanism for controlling the spread of the epidemic. The results also show the presence of a kind of genetic evolution in vector population, which results mainly in increasing the average lifespan of individuals in adulthood.

  12. Aedes aegypti (L.) and Aedes albopictus (Skuse) in Singapore City

    PubMed Central

    Chan, K. L.; Chan, Y. C.; Ho, B. C.

    1971-01-01

    There is a current belief stemming from statements made in the literature that Ae. aegypti is displacing Ae. albopictus in a number of cities of South-East Asia and in Calcutta, India. A critical review of these works showed that either the observations were inconclusive or the methods of collection were biased for one or the other species. Extensive surveys of the larval habitats of the two species in Singapore showed that the sharing of breeding habitats was uncommon in both urban and rural areas. In the laboratory, Ae. aegypti took a slightly shorter time to complete its development from egg-hatching to adult emergence. It is concluded that information available at present is insufficient to interpret the Ae. aegypti—Ae. albopictus population balance resulting from interspecific competition in Singapore. The pattern of distribution of the two species is unlikely to be the result of competitive displacement; it is, rather, probable that this pattern results from factors that favour the rapid increase and spread of one species over the other. It is suggested that Ae. aegypti in the city is favoured by rapid and extensive urbanization and by the higher fecundity and shorter life cycle of the species. PMID:5316748

  13. Mosquito attractant blends to trap host seeking Aedes aegypti.

    PubMed

    Mathew, Nisha; Ayyanar, Elango; Shanmugavelu, Sabesan; Muthuswamy, Kalyanasundaram

    2013-03-01

    Aedes aegypti is the key vector of three important arboviral diseases -dengue, yellow fever and chikungunya. To identify volatile chemicals which could be used in odour based traps for Aedes mosquito surveillance, a few synthetic compounds and compound blends have been evaluated in an indigenously designed olfactometer. A total of 24 compounds and seven compound blends were screened against unfed adult female Ae. aegypti mosquitoes for attraction and compared with control group. The attractancy or repellency index of the test material to mosquitoes was calculated and rated them as class-1, class-2 and class-3 with rating values ranging 1-15, 16-33 and 34-100 respectively. Out of the 24 compounds tested, six were showing significant attractancy (P < 0.05) and among that 1-octene-3-ol showed maximum attractancy with a rating value of 57.81. Sixteen compounds showed significant repellency (P < 0.05) and among that with a rating value of 72.47, 1-hexene-3-ol showed strong repellent action against Ae. aegypti. All the seven blends showed significant mosquito attractancy (P < 0.05) and among that with a rating of 62.08 Myristic acid, Lactic acid and CO(2) blend exhibited first-rate mosquito attractancy.

  14. Comprehensive DNA methylation analysis of the Aedes aegypti genome

    PubMed Central

    Falckenhayn, Cassandra; Carneiro, Vitor Coutinho; de Mendonça Amarante, Anderson; Schmid, Katharina; Hanna, Katharina; Kang, Seokyoung; Helm, Mark; Dimopoulos, George; Fantappié, Marcelo Rosado; Lyko, Frank

    2016-01-01

    Aedes aegypti mosquitoes are important vectors of viral diseases. Mosquito host factors play key roles in virus control and it has been suggested that dengue virus replication is regulated by Dnmt2-mediated DNA methylation. However, recent studies have shown that Dnmt2 is a tRNA methyltransferase and that Dnmt2-dependent methylomes lack defined DNA methylation patterns, thus necessitating a systematic re-evaluation of the mosquito genome methylation status. We have now searched the Ae. aegypti genome for candidate DNA modification enzymes. This failed to reveal any known (cytosine-5) DNA methyltransferases, but identified homologues for the Dnmt2 tRNA methyltransferase, the Mettl4 (adenine-6) DNA methyltransferase, and the Tet DNA demethylase. All genes were expressed at variable levels throughout mosquito development. Mass spectrometry demonstrated that DNA methylation levels were several orders of magnitude below the levels that are usually detected in organisms with DNA methylation-dependent epigenetic regulation. Furthermore, whole-genome bisulfite sequencing failed to reveal any evidence of defined DNA methylation patterns. These results suggest that the Ae. aegypti genome is unmethylated. Interestingly, additional RNA bisulfite sequencing provided first evidence for Dnmt2-mediated tRNA methylation in mosquitoes. These findings have important implications for understanding the mechanism of Dnmt2-dependent virus regulation. PMID:27805064

  15. Vertical Transmission of Zika Virus in Aedes aegypti Mosquitoes

    PubMed Central

    Thangamani, Saravanan; Huang, Jing; Hart, Charles E.; Guzman, Hilda; Tesh, Robert B.

    2016-01-01

    Previous experimental studies have demonstrated that a number of mosquito-borne flavivirus pathogens are vertically transmitted in their insect vectors, providing a mechanism for these arboviruses to persist during adverse climatic conditions or in the absence of a susceptible vertebrate host. In this study, designed to test whether Zika virus (ZIKV) could be vertically transmitted, female Aedes aegypti and Aedes albopictus were injected with ZIKV, and their F1 adult progeny were tested for ZIKV infection. Six of 69 Ae. aegypti pools, comprised of a total of 1,738 F1 adults, yielded ZIKV upon culture, giving a minimum filial infection rate of 1:290. In contrast, none of 803 F1 Ae. albopictus adults (32 pools) yielded ZIKV. The MFIR for Ae. aegypti was comparable to MFIRs reported for other flaviviruses in mosquitoes, including dengue, Japanese encephalitis, yellow fever, West Nile, and St. Louis encephalitis viruses. The results suggest that vertical transmission may provide a potential mechanism for the virus to survive during adverse conditions. PMID:27573623

  16. Cost effectiveness of Aedes aegypti control programmes: participatory versus vertical.

    PubMed

    Baly, A; Toledo, M E; Boelaert, M; Reyes, A; Vanlerberghe, V; Ceballos, E; Carvajal, M; Maso, R; La Rosa, M; Denis, O; Van der Stuyft, P

    2007-06-01

    We conducted an economic appraisal of two strategies for Aedes aegypti control: a vertical versus a community-based approach. Costs were calculated for the period 2000-2002 in three pilot areas of Santiago de Cuba where a community intervention was implemented and compared with three control areas with routine vertical programme activities. Reduction in A. aegypti foci was chosen as the measure of effectiveness. The pre-intervention number of foci (614 vs. 632) and economical costs for vector control (US$243746 vs. US$263486) were comparable in the intervention and control areas. During the intervention period (2001-2002), a 13% decrease in recurrent costs for the health system was observed. Within the control areas, these recurrent relative costs remained stable. The number of A. aegypti foci in the pilot areas and the control areas fell by 459 and 467, respectively. The community-based approach was more cost effective from a health system perspective (US$964 vs. US$1406 per focus) as well as from society perspective (US$1508 vs. US$1767 per focus).

  17. Comprehensive DNA methylation analysis of the Aedes aegypti genome.

    PubMed

    Falckenhayn, Cassandra; Carneiro, Vitor Coutinho; de Mendonça Amarante, Anderson; Schmid, Katharina; Hanna, Katharina; Kang, Seokyoung; Helm, Mark; Dimopoulos, George; Fantappié, Marcelo Rosado; Lyko, Frank

    2016-11-02

    Aedes aegypti mosquitoes are important vectors of viral diseases. Mosquito host factors play key roles in virus control and it has been suggested that dengue virus replication is regulated by Dnmt2-mediated DNA methylation. However, recent studies have shown that Dnmt2 is a tRNA methyltransferase and that Dnmt2-dependent methylomes lack defined DNA methylation patterns, thus necessitating a systematic re-evaluation of the mosquito genome methylation status. We have now searched the Ae. aegypti genome for candidate DNA modification enzymes. This failed to reveal any known (cytosine-5) DNA methyltransferases, but identified homologues for the Dnmt2 tRNA methyltransferase, the Mettl4 (adenine-6) DNA methyltransferase, and the Tet DNA demethylase. All genes were expressed at variable levels throughout mosquito development. Mass spectrometry demonstrated that DNA methylation levels were several orders of magnitude below the levels that are usually detected in organisms with DNA methylation-dependent epigenetic regulation. Furthermore, whole-genome bisulfite sequencing failed to reveal any evidence of defined DNA methylation patterns. These results suggest that the Ae. aegypti genome is unmethylated. Interestingly, additional RNA bisulfite sequencing provided first evidence for Dnmt2-mediated tRNA methylation in mosquitoes. These findings have important implications for understanding the mechanism of Dnmt2-dependent virus regulation.

  18. Functional Development of the Octenol Response in Aedes aegypti

    PubMed Central

    Bohbot, Jonathan D.; Durand, Nicolas F.; Vinyard, Bryan T.; Dickens, Joseph C.

    2013-01-01

    Attraction of female Aedes aegypti mosquitoes to 1-octen-3-ol (octenol), CO2, lactic acid, or ammonia emitted by vertebrate hosts is not only contingent on the presence of odorants in the environment, but is also influenced by the insect’s physiological state. For anautogenous mosquito species, like A. aegypti, newly emerged adult females neither respond to host odors nor engage in blood-feeding; the bases for these behaviors are poorly understood. Here we investigated detection of two components of an attractant blend emitted by vertebrate hosts, octenol, and CO2, by female A. aegypti mosquitoes using electrophysiological, behavioral, and molecular approaches. An increase in sensitivity of octenol olfactory receptor neurons (ORNs) was correlated with an increase in odorant receptor gene (Or) expression and octenol-mediated attractive behavior from day 1 to day 6 post-emergence. While the sensitivity of octenol ORNs was maintained through day 10, behavioral responses to octenol decreased as did the ability of females to discriminate between octenol and octenol + CO2. Our results show differing age-related roles for the peripheral receptors for octenol and higher order neural processing in the behavior of female mosquitoes. PMID:23471139

  19. Formulas of components of citronella oil against mosquitoes (Aedes aegypti).

    PubMed

    Hsu, Wey-Shin; Yen, Jui-Hung; Wang, Yei-Shung

    2013-01-01

    The mosquito Aedes aegypti is an epidemic vector of several diseases such as dengue fever and yellow fever. Several pesticides are used to control the mosquito population. Because of their frequent use, some mosquitoes have developed resistance. In this study, we used the Y-tube olfactometer to test essential oils of Cymbopogon species and screened specific formulas of components as repellents against Ae. aegypti. At 400 μL, the extracted oil of citronella grass (Cymbopogon nardus) and myrcene produced a low-active response by inhibiting mosquito host-seeking activity. Citronella grass, lemon grass (Cymbopogon citratus), citral and myrcene also produced a low-treatment response to repellents, for more potential to affect host-seeking behavior. Furthermore, the mixture of citral, myrcene, and citronellal oil (C:M:Ci = 6:4:1) greatly affected and inhibited host-seeking behavior (76% active response; 26% treatment response with 40 μL; 42.5%, 18% with 400 μL; and 19%, 23% with 1000 μL). As compared with the result for N,N-diethyl-3-methylbenzamide (DEET; 44%, 22% with 400 μL), adjusting the composition formulas of citronella oil had a synergistic effect, for more effective repellent against Ae. aegypti.

  20. Chikungunya virus susceptibility & variation in populations of Aedes aegypti (Diptera: Culicidae) mosquito from India

    PubMed Central

    Gokhale, Mangesh D.; Paingankar, Mandar S.; Sudeep, Anakathil B.; Parashar, Deepti

    2015-01-01

    Background & objectives: Although having immense clinical relevance, yet only a few studies have been targeted to understand the chikungunya virus (CHIKV) susceptibility and growth in Aedes aegypti populations from India. This study was undertaken to investigate CHIKV susceptibility and growth kinetics in Ae. aegypti along with genetic heterogeneity of Ae. aegypti populations. Methods: Dose dependent CHIKV susceptibility and growth kinetic studies for three CHIKV strains reported from India were carried out in Ae. aegypti mosquito populations. The phenotypic variation and genetic heterogeneity in five Ae. aegypti populations were investigated using multivariate morphometrics and allozyme variation studies. Results: The dissemination and growth kinetics studies of the three CHIKV strains showed no selective advantage for a particular strain of CHIKV in Ae. aegypti. At 100 per cent infection rate, five geographic Ae. aegypti populations showed differences in dissemination to three CHIKV strains. Morphometric studies revealed phenotypic variation in all the studied populations. The allelic frequencies, F statistics, and Nei's genetic identity values showed that genetic differences between the populations were small, but significant. Interpretation & conclusions: The results obtained in this study suggest that genetic background of the vector strongly influences the CHIKV susceptibility in Ae. aegypti. PMID:26905240

  1. Multiple factors contribute to anautogenous reproduction by the mosquito Aedes aegypti.

    PubMed

    Gulia-Nuss, Monika; Elliot, Anne; Brown, Mark R; Strand, Michael R

    2015-11-01

    Aedes aegypti is an anautogenous mosquito that must blood feed on a vertebrate host to produce and lay a clutch of eggs. The rockpool mosquito, Georgecraigius atropalpus, is related to A. aegypti but is a facultatively autogenous species that produces its first clutch of eggs shortly after emerging without blood feeding. Consumption of a blood meal by A. aegypti triggers the release of ovary ecdysteroidogenic hormone (OEH) and insulin-like peptide 3 (ILP3) from the brain, which stimulate egg formation. OEH and ILP3 also stimulate egg formation in G. atropalpus but are released at eclosion independently of blood feeding. These results collectively suggest that blood meal dependent release of OEH and ILP3 is one factor that prevents A. aegypti from reproducing autogenously. Here, we examined two other factors that potentially inhibit autogeny in A. aegypti: teneral nutrient reserves and the ability of OEH and ILP3 to stimulate egg formation in the absence of blood feeding. Measures of nutrient reserves showed that newly emerged A. aegypti females had similar wet weights but significantly lower protein and glycogen reserves than G. atropalpus females when larvae were reared under identical conditions. OEH stimulated non-blood fed A. aegypti females to produce ecdysteroid hormone and package yolk into oocytes more strongly than ILP3. OEH also reduced host seeking and blood feeding behavior, yet females produced few mature eggs. Overall, our results indicate that multiple factors prevent A. aegypti from reproducing autogenously.

  2. Imidacloprid impairs the post-embryonic development of the midgut in the yellow fever mosquito Stegomyia aegypti (=Aedes aegypti).

    PubMed

    Fernandes, K M; Gonzaga, W G; Pascini, T V; Miranda, F R; Tomé, H V V; Serrão, J E; Martins, G F

    2015-09-01

    The mosquito Stegomyia aegypti (=Aedes aegypti) (Diptera: Culicidae) is a vector for the dengue and yellow fever viruses. As blood digestion occurs in the midgut, this organ constitutes the route of entry of many pathogens. The effects of the insecticide imidacloprid on the survival of St. aegypti were investigated and the sub-lethal effects of the insecticide on midgut development were determined. Third instar larvae were exposed to different concentrations of imidacloprid (0.15, 1.5, 3.0, 6.0 and 15.0 p.p.m.) and survival was monitored every 24 h for 10 days. Midguts from imidacloprid-treated insects at different stages of development were dissected and processed for analyses by transmission electron microscopy, immunofluorescence microscopy and terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) assays. Imidacloprid concentrations of 3.0 and 15.0 p.p.m. were found to affect midgut development similarly. Digestive cells of the fourth instar larvae (L4) midgut exposed to imidacloprid had more multilamellar bodies, abundantly found in the cell apex, and more electron-lucent vacuoles in the basal region compared with those from untreated insects. Moreover, imidacloprid interfered with the differentiation of regenerative cells, dramatically reducing the number of digestive and endocrine cells and leading to malformation of the midgut epithelium in adults. The data demonstrate that imidacloprid can reduce the survival of mosquitoes and thus indicate its potentially high efficacy in the control of St. aegypti populations.

  3. The wMel strain of Wolbachia Reduces Transmission of Zika virus by Aedes aegypti

    PubMed Central

    Aliota, Matthew T.; Peinado, Stephen A.; Velez, Ivan Dario; Osorio, Jorge E.

    2016-01-01

    Zika virus (ZIKV) is causing an explosive outbreak of febrile disease in the Americas. There are no effective antiviral therapies or licensed vaccines for this virus, and mosquito control strategies have not been adequate to contain the virus. A promising candidate for arbovirus control and prevention relies on the introduction of the intracellular bacterium Wolbachia into Aedes aegypti mosquitoes. This primarily has been proposed as a tool to control dengue virus (DENV) transmission; however, evidence suggests Wolbachia infections confer protection for Ae. aegypti against other arboviruses. At present, it is unknown whether or not ZIKV can infect, disseminate, and be transmitted by Wolbachia-infected Ae. aegypti. Using Ae. aegypti infected with the wMel strain of Wolbachia that are being released in Medellin, Colombia, we report that these mosquitoes have reduced vector competence for ZIKV. These results support the use of Wolbachia biocontrol as a multivalent strategy against Ae. aegypti-transmitted viruses. PMID:27364935

  4. Diversity of containers and buildings infested with Aedes aegypti in Puerto Iguazú, Argentina.

    PubMed

    Costa, Federico; Fattore, Gladys; Abril, Marcelo

    2012-09-01

    Aedes aegypti is the main domestic vector of the dengue virus. Control measures to prevent dengue transmission focus on the treatment and elimination of this vector's oviposition sites. There is limited biological information on Ae. aegypti in Argentina. The aim of this study was to characterize Ae. aegypti oviposition sites in the city of Puerto Iguazú, Argentina. We surveyed an area covering nine neighborhoods in 2005. We identified 191 premises as positive for Ae. aegypti, giving a general house index of 9.6%. Premises classified as residential and vacant lots presented the highest number of infested premises, with 9% and 22% respectively. The total number of surveyed containers was 29,600. The overall container index (CI) was 1.1. The most frequently infested containers were water tanks (CI = 37). These preliminary results suggest that vacant lots and water tanks provide suitable breeding areas and environmental conditions, improving the chances of Ae. aegypti survival in Puerto Iguazú.

  5. Shifting Patterns of Aedes aegypti Fine Scale Spatial Clustering in Iquitos, Peru

    PubMed Central

    LaCon, Genevieve; Morrison, Amy C.; Astete, Helvio; Stoddard, Steven T.; Paz-Soldan, Valerie A.; Elder, John P.; Halsey, Eric S.; Scott, Thomas W.; Kitron, Uriel; Vazquez-Prokopec, Gonzalo M.

    2014-01-01

    Background Empiric evidence shows that Aedes aegypti abundance is spatially heterogeneous and that some areas and larval habitats produce more mosquitoes than others. There is a knowledge gap, however, with regards to the temporal persistence of such Ae. aegypti abundance hotspots. In this study, we used a longitudinal entomologic dataset from the city of Iquitos, Peru, to (1) quantify the spatial clustering patterns of adult Ae. aegypti and pupae counts per house, (2) determine overlap between clusters, (3) quantify the temporal stability of clusters over nine entomologic surveys spaced four months apart, and (4) quantify the extent of clustering at the household and neighborhood levels. Methodologies/Principal Findings Data from 13,662 household entomological visits performed in two Iquitos neighborhoods differing in Ae. aegypti abundance and dengue virus transmission was analyzed using global and local spatial statistics. The location and extent of Ae. aegypti pupae and adult hotspots (i.e., small groups of houses with significantly [p<0.05] high mosquito abundance) were calculated for each of the 9 entomologic surveys. The extent of clustering was used to quantify the probability of finding spatially correlated populations. Our analyses indicate that Ae. aegypti distribution was highly focal (most clusters do not extend beyond 30 meters) and that hotspots of high vector abundance were common on every survey date, but they were temporally unstable over the period of study. Conclusions/Significance Our findings have implications for understanding Ae. aegypti distribution and for the design of surveillance and control activities relying on household-level data. In settings like Iquitos, where there is a relatively low percentage of Ae. aegypti in permanent water-holding containers, identifying and targeting key premises will be significantly challenged by shifting hotspots of Ae. aegypti infestation. Focusing efforts in large geographic areas with historically

  6. Spatial and temporal patterns of abundance of Aedes aegypti L. (Stegomyia aegypti) and Aedes albopictus (Skuse) [Stegomyia albopictus (Skuse)] in southern Florida.

    PubMed

    Reiskind, M H; Lounibos, L P

    2013-12-01

    Invasion by mosquito vectors of disease may impact the distribution of resident mosquitoes, resulting in novel patterns of vectors and concomitant risk for disease. One example of such an impact is the invasion by Aedes albopictus (Skuse) [Stegomyia albopictus (Skuse)] (Diptera: Culicidae) of North America and this species' interaction with Aedes aegypti L. (Stegomyia aegypti L). We hypothesized that Ae. aegypti would be found in urban, coastal areas that experience hotter and drier conditions, whereas Ae. albopictus would be more commonly found in suburban and rural areas that are cooler and wetter. In addition, we hypothesized that Ae. aegypti would be more abundant early in the wet season, whereas Ae. albopictus would be more abundant later in the wet season. Urban areas were drier, hotter and contained more Ae. aegypti than suburban or rural areas. Aedes aegypti was relatively more abundant early in the wet season, whereas Ae. albopictus was more abundant in both the late wet season and the dry season. The spatial patterns of inter- and intraspecific encounters between these species were also described. The distribution of these mosquitoes is correlated with abiotic conditions, and with temperature, humidity and the relative availability of rain-filled containers. Understanding the ecological determinants of species distribution can provide insight into the biology of these vectors and important information for their appropriate control.

  7. Gene flow pattern among Aedes aegypti populations in Mexico.

    PubMed

    de Lourdes Muñoz, Maria; Mercado-Curiel, Ricardo F; Diaz-Badillo, Alvaro; Pérez Ramirez, Gerardo; Black, William C

    2013-03-01

    Patterns of gene flow vary greatly among Aedes aegypti populations throughout Mexico. The populations are panmictic along the Pacific coast, isolated by distance in northeast Mexico, and exhibit moderate gene flow across the Yucatan peninsula. Nine Ae. aegypti collections from 6 cities in Oaxaca, Mexico, were taken to examine the local patterns of gene flow. Genetic variation was examined in a 387-bp region of the nicotinamide adenine dinucleotide dehydrogenase subunit 4 mitochondrial gene (ND4) using single-strand conformation polymorphism analysis, and 3 haplotypes were detected. Cluster analysis on the linearized FST genetic distances failed to group collections in geographic proximity. Regression analysis of linear or road distances on linearized F(ST) indicated that proximal collections were as diverse as distant collections across an approximately 800-km range. The geographical distribution of the Mexican mosquito haplotype frequencies was determined for the ND4 sequences from 524 individuals from Oaxaca (this study) and 2,043 individuals from our previous studies. Herein, we report on yet another pattern dominated by genetic drift among 9 Ae. aegypti collections from 6 cities in Oaxaca, Mexico, and compare it to those reported in other regions of Mexico. Molecular analysis of variance showed that there was as much genetic variation among collections 4 km apart as there was among all collections. The numbers of haplotypes and the amount of genetic diversity among the collections from Oaxaca were much lower than detected in previous studies in other regions of Mexico and may reflect the effects of control efforts or adaptations to the altitudinal limits (1,500 m) of the species in Mexico. The geographical distribution of mosquito haplotypes in Mexico is also reported. Furthermore, based on the distribution of the mosquito haplotypes in America, we suggest that mosquito dispersion is very efficient, most likely due to commercial transportation.

  8. Aedes aegypti Larvicidal Sesquiterpene Alkaloids from Maytenus oblongata.

    PubMed

    Touré, Seindé; Nirma, Charlotte; Falkowski, Michael; Dusfour, Isabelle; Boulogne, Isabelle; Jahn-Oyac, Arnaud; Coke, Maïra; Azam, Didier; Girod, Romain; Moriou, Céline; Odonne, Guillaume; Stien, Didier; Houël, Emeline; Eparvier, Véronique

    2017-02-24

    Four new sesquiterpene alkaloids (1-4) with a β-dihydroagrofuran skeleton and a new triterpenoid (5) were isolated from an ethyl acetate extract of Maytenus oblongata stems. Their structures were elucidated using 1D and 2D NMR spectroscopy as well as MS and ECD experiments. The M. oblongata stem EtOAc extract and the pure compounds isolated were tested for larvicidal activity against Aedes aegypti under laboratory conditions, and compounds 2 and 3 were found to be active.

  9. Mitochondrial Gene Cytochrome b Developmental and Environmental Expression in Aedes aegypti (Diptera: Culicidae)

    DTIC Science & Technology

    2009-11-01

    Experiments. Adult female (3- and 10- d-old) Ae. aegypti were treated topically with per- methrin/acetone at 2.5 105 g (high dose, HD) and 1.25 105...downwas recorded for each collection time point and at 24 h postpermethrin treatment (Supplemental Ta- ble 5). Heat-ShockExperiments.Ae. aegypti females ...Radiation Experiments. For the UV-radiation time course study, Ae. aegypti females (3, 10, and 17 d old)wereexposed toagermicidal lamp(30W,G30TB, General

  10. Dengue virus detection in Aedes aegypti larvae from southeastern Brazil.

    PubMed

    Cecílio, Samyra Giarola; Júnior, Willer Ferreira Silva; Tótola, Antônio Helvécio; de Brito Magalhães, Cíntia Lopes; Ferreira, Jaqueline Maria Siqueira; de Magalhães, José Carlos

    2015-06-01

    The transmission of dengue, the most important arthropod-borne viral disease in Brazil, has been intensified over the past decades, along with the accompanying expansion and adaptation of its Aedes vectors. In the present study, we mapped dengue vectors in Ouro Preto and Ouro Branco, Minas Gerais, by installing ovitraps in 32 public schools. The traps were examined monthly between September, 2011 through July, 2012 and November, 2012 to April, 2013. The larvae were reared until the fourth stadium and identified according to species. The presence of dengue virus was detected by real time PCR and agarose gel electrophoresis. A total of 1,945 eggs was collected during the 17 months of the study. The Ovitrap Positivity Index (OPI) ranged from 0 to 28.13% and the Eggs Density Index (EDI) ranged from 0 to 59.9. The predominant species was Aedes aegypti, with 84.9% of the hatched larvae. Although the collection was low when compared to other ovitraps studies, vertical transmission could be detected. Of the 54 pools, dengue virus was detected in four Ae. aegypti pools.

  11. Origin of the Dengue Fever Mosquito, Aedes aegypti, in California

    PubMed Central

    Gloria-Soria, Andrea; Brown, Julia E.; Kramer, Vicki; Hardstone Yoshimizu, Melissa; Powell, Jeffrey R.

    2014-01-01

    Dengue fever is among the most widespread vector-borne infectious diseases. The primary vector of dengue is the Aedes aegypti mosquito. Ae. aegypti is prevalent in the tropics and sub-tropics and is closely associated with human habitats outside its native range of Africa. While long established in the southeastern United States of America where dengue is re-emerging, breeding populations have never been reported from California until the summer of 2013. Using 12 highly variable microsatellite loci and a database of reference populations, we have determined that the likely source of the California introduction is the southeastern United States, ruling out introductions from abroad, from the geographically closer Arizona or northern Mexico populations, or an accidental release from a research laboratory. The power to identify the origin of new introductions of invasive vectors of human disease relies heavily on the availability of a panel of reference populations. Our work demonstrates the importance of generating extensive reference databases of genetically fingerprinted human-disease vector populations to aid public health efforts to prevent the introduction and spread of vector-borne diseases. PMID:25077804

  12. Effect of Photoperiod On Permethrin Resistance In Aedes aegypti.

    PubMed

    Villanueva, O Karina; Ponce, Gustavo; Lopez, Beatriz; Gutierrez, Selene M; Rodriguez, Iram P; Reyes, Guadalupe; Saavedra, Karla J; Black, William C; Garcia, Julian; Beaty, Barry; Eisen, Lars; Flores, Adriana E

    2016-12-01

    Living organisms have been exposed to light-dark cycles that allowed them to adapt to different ecological niches. Circadian cycles affect hormone release, metabolism, and response to xenobiotic compounds. Current studies have shown that insect susceptibility to toxic agents depends on circadian cycles, mainly because the biochemical processes involved in detoxification and responses to oxidative stress are modulated by this process. The goal of this study was to determine the effect of photoperiod on resistance to permethrin in Aedes aegypti . Collections of Ae. aegypti from 4 locations in Yucatan, southern Mexico, were subjected to 2 different photoperiod schemes: dark (0 h light:24 h dark) and natural photoperiod (12 h light:12 h dark). The comparison of both photoperiods was evaluated with respect to permethrin resistance using bottle bioassays and by monitoring the possible mechanism related such as enzymatic activity and by the frequency of 2 knockdown resistance mutations in the voltage-dependent sodium channel gene (V1016I and F1534C). The susceptible strain was used as a reference. The mosquitoes in dark photoperiod showed a reduction in resistance to the pyrethroid. The α-esterases and glutathione S-transferase enzymatic activities showed lower levels in the dark photoperiod, and the frequencies of V1016I knockdown resistance mutation showed significant difference between photoperiod schemes.

  13. Inhibition of Zika virus by Wolbachia in Aedes aegypti

    PubMed Central

    Caragata, Eric Pearce; Dutra, Heverton Leandro Carneiro; Moreira, Luciano Andrade

    2016-01-01

    Through association with cases of microcephaly in 2015, Zika virus (ZIKV) has transitioned from a relatively unknown mosquito-transmitted pathogen to a global health emergency, emphasizing the need to improve existing mosquito control programs to prevent future disease outbreaks. The response to Zika must involve a paradigm shift from traditional to novel methods of mosquito control, and according to the World Health Organization should incorporate the release of mosquitoes infected with the bacterial endosymbiont Wolbachia pipientis. In our recent paper [Dutra, HLC et al., Cell Host & Microbe 2016] we investigated the potential of Wolbachia infections in Aedes aegypti to restrict infection and transmission of Zika virus recently isolated in Brazil. Wolbachia is now well known for its ability to block or reduce infection with a variety of pathogens in different mosquito species including the dengue (DENV), yellow fever, and chikungunya viruses, and malaria-causing Plasmodium, and consequently has great potential to control mosquito-transmitted diseases across the globe. Our results demonstrated that the wMel Wolbachia strain in Brazilian Ae. aegypti is a strong inhibitor of ZIKV infection, and furthermore appears to prevent transmission of infectious viral particles in mosquito saliva, which highlights the bacterium’s suitability for more widespread use in Zika control. PMID:28357366

  14. Regulation of Antimicrobial Peptides in Aedes aegypti Aag2 Cells.

    PubMed

    Zhang, Rudian; Zhu, Yibin; Pang, Xiaojing; Xiao, Xiaoping; Zhang, Renli; Cheng, Gong

    2017-01-01

    Antimicrobial peptides (AMPs) are an important group of immune effectors that play a role in combating microbial infections in invertebrates. Most of the current information on the regulation of insect AMPs in microbial infection have been gained from Drosophila, and their regulation in other insects are still not completely understood. Here, we generated an AMP induction profile in response to infections with some Gram-negative, -positive bacteria, and fungi in Aedes aegypti embryonic Aag2 cells. Most of the AMP inductions caused by the gram-negative bacteria was controlled by the Immune deficiency (Imd) pathway; nonetheless, Gambicin, an AMP gene discovered only in mosquitoes, was combinatorially regulated by the Imd, Toll and JAK-STAT pathways in the Aag2 cells. Gambicin promoter analyses including specific sequence motif deletions implicated these three pathways in Gambicin activity, as shown by a luciferase assay. Moreover, the recognition between Rel1 (refer to Dif/Dorsal in Drosophila) and STAT and their regulatory sites at the Gambicin promoter site was validated by a super-shift electrophoretic mobility shift assay (EMSA). Our study provides information that increases our understanding of the regulation of AMPs in response to microbial infections in mosquitoes. And it is a new finding that the A. aegypti AMPs are mainly regulated Imd pathway only, which is quite different from the previous understanding obtained from Drosophila.

  15. Regulation of Antimicrobial Peptides in Aedes aegypti Aag2 Cells

    PubMed Central

    Zhang, Rudian; Zhu, Yibin; Pang, Xiaojing; Xiao, Xiaoping; Zhang, Renli; Cheng, Gong

    2017-01-01

    Antimicrobial peptides (AMPs) are an important group of immune effectors that play a role in combating microbial infections in invertebrates. Most of the current information on the regulation of insect AMPs in microbial infection have been gained from Drosophila, and their regulation in other insects are still not completely understood. Here, we generated an AMP induction profile in response to infections with some Gram-negative, -positive bacteria, and fungi in Aedes aegypti embryonic Aag2 cells. Most of the AMP inductions caused by the gram-negative bacteria was controlled by the Immune deficiency (Imd) pathway; nonetheless, Gambicin, an AMP gene discovered only in mosquitoes, was combinatorially regulated by the Imd, Toll and JAK-STAT pathways in the Aag2 cells. Gambicin promoter analyses including specific sequence motif deletions implicated these three pathways in Gambicin activity, as shown by a luciferase assay. Moreover, the recognition between Rel1 (refer to Dif/Dorsal in Drosophila) and STAT and their regulatory sites at the Gambicin promoter site was validated by a super-shift electrophoretic mobility shift assay (EMSA). Our study provides information that increases our understanding of the regulation of AMPs in response to microbial infections in mosquitoes. And it is a new finding that the A. aegypti AMPs are mainly regulated Imd pathway only, which is quite different from the previous understanding obtained from Drosophila. PMID:28217557

  16. Origin of the dengue fever mosquito, Aedes aegypti, in California.

    PubMed

    Gloria-Soria, Andrea; Brown, Julia E; Kramer, Vicki; Hardstone Yoshimizu, Melissa; Powell, Jeffrey R

    2014-01-01

    Dengue fever is among the most widespread vector-borne infectious diseases. The primary vector of dengue is the Aedes aegypti mosquito. Ae. aegypti is prevalent in the tropics and sub-tropics and is closely associated with human habitats outside its native range of Africa. While long established in the southeastern United States of America where dengue is re-emerging, breeding populations have never been reported from California until the summer of 2013. Using 12 highly variable microsatellite loci and a database of reference populations, we have determined that the likely source of the California introduction is the southeastern United States, ruling out introductions from abroad, from the geographically closer Arizona or northern Mexico populations, or an accidental release from a research laboratory. The power to identify the origin of new introductions of invasive vectors of human disease relies heavily on the availability of a panel of reference populations. Our work demonstrates the importance of generating extensive reference databases of genetically fingerprinted human-disease vector populations to aid public health efforts to prevent the introduction and spread of vector-borne diseases.

  17. Characteristics of the spatial pattern of the dengue vector, Aedes aegypti, in Iquitos, Peru.

    PubMed

    Getis, Arthur; Morrison, Amy C; Gray, Kenneth; Scott, Thomas W

    2003-11-01

    We determine the spatial pattern of Aedes aegypti and the containers in which they develop in two neighborhoods of the Amazonian city of Iquitos, Peru. Four variables were examined: adult Ae. aegypti, pupae, containers positive for larvae or pupae, and all water-holding containers. Adults clustered strongly within houses and weakly to a distance of 30 meters beyond the household; clustering was not detected beyond 10 meters for positive containers or pupae. Over short periods of time restricted flight range and frequent blood-feeding behavior of Ae. aegypti appear to be underlying factors in the clustering patterns of human dengue infections. Permanent, consistently infested containers (key premises) were not major producers of Ae. aegypti, indicating that larvaciding strategies by themselves may be less effective than reduction of mosquito development sites by source reduction and education campaigns. We conclude that entomologic risk of human dengue infection should be assessed at the household level at frequent time intervals.

  18. First Report of Aedes aegypti Transmission of Chikungunya Virus in the Americas

    PubMed Central

    Díaz-González, Esteban E.; Kautz, Tiffany F.; Dorantes-Delgado, Alicia; Malo-García, Iliana R.; Laguna-Aguilar, Maricela; Langsjoen, Rose M.; Chen, Rubing; Auguste, Dawn I.; Sánchez-Casas, Rosa M.; Danis-Lozano, Rogelio; Weaver, Scott C.; Fernández-Salas, Ildefonso

    2015-01-01

    During a chikungunya fever outbreak in late 2014 in Chiapas, Mexico, entomovirological surveillance was performed to incriminate the vector(s). In neighborhoods, 75 households with suspected cases were sampled for mosquitoes, of which 80% (60) harbored Aedes aegypti and 2.7% (2) Aedes albopictus. A total of 1,170 Ae. aegypti and three Ae. albopictus was collected and 81 pools were generated. Although none of the Ae. albopictus pools were chikungunya virus (CHIKV)–positive, 18 Ae. aegypti pools (22.8%) contained CHIKV, yielding an infection rate of 32.3/1,000 mosquitoes. A lack of herd immunity in conjunction with high mosquito populations, poor vector control services in this region, and targeted collections in locations of human cases may explain the high infection rate in this vector. Consistent with predictions from experimental studies, Ae. aegypti appears to be the principal vector of CHIKV in southern Mexico, while the role of Ae. albopictus remains unknown. PMID:26416113

  19. Atmospheric control of Aedes aegypti populations in Buenos Aires (Argentina) and its variability

    NASA Astrophysics Data System (ADS)

    de Garín, A.; Bejarán, R. A.; Carbajo, A. E.; de Casas, S. C.; Schweigmann, N. J.

    The mosquito Aedes aegypti is the main urban vector responsible for the transmission of dengue fever and dengue hemorrhagic fever. The city of Buenos Aires, Argentina, is located at the southern end of the world distribution of the species. The population abundance of Ae. aegypti is mainly regulated by environmental factors. We calculated the potential number of times that a female could lay eggs during its mean life expectancy, based on potential egg production and daily meteorological records. The model considers those variables implying physical hazard to the survival of Ae. aegypti, mosquito flying activity and oviposition. The results, obtained after calibration and validation of the model with field observations, show significant correlation (P<0.001) for different lags depending on the life stage. From these results, more favorable atmospheric conditions for Ae. aegypti reproduction (linked to the urban climatic change) can be observed. The climatic variability in the last decade resembles conditions at the end of 19th century.

  20. Dispersal of Male Aedes aegypti in a Coastal Village in Southern Mexico

    PubMed Central

    Valerio, Laura; Facchinelli, Luca; Ramsey, Janine M.; Scott, Thomas W.

    2012-01-01

    Most Aedes aegypti dispersal studies have focused on females because of their central role in dengue virus transmission. Only a few mark-release-recapture (MRR) studies provided insights into male Ae. aegypti dispersal. To fill this knowledge gap, we conducted five male Ae. aegypti MRR experiments in a coastal village in southern Mexico. Small and large male cohorts were marked with fluorescent dusts, released outside buildings, and recaptures were carried out by using backpack aspirators. Recapture rates ranged between 0.35% and 6.55% and median distance traveled was 12–166 meters. A statistically significant difference in median distance traveled with large males dispersing farther than small ones was detected only in one experiment (MRR5: U = 3.5, P < 0.01). Male dispersal data will be useful for constructing and estimating parameter values and validating models that will be used to plan the most effective release strategies for genetically modified male Ae. aegypti. PMID:22492152

  1. First Report of Aedes aegypti Transmission of Chikungunya Virus in the Americas.

    PubMed

    Díaz-González, Esteban E; Kautz, Tiffany F; Dorantes-Delgado, Alicia; Malo-García, Iliana R; Laguna-Aguilar, Maricela; Langsjoen, Rose M; Chen, Rubing; Auguste, Dawn I; Sánchez-Casas, Rosa M; Danis-Lozano, Rogelio; Weaver, Scott C; Fernández-Salas, Ildefonso

    2015-12-01

    During a chikungunya fever outbreak in late 2014 in Chiapas, Mexico, entomovirological surveillance was performed to incriminate the vector(s). In neighborhoods, 75 households with suspected cases were sampled for mosquitoes, of which 80% (60) harbored Aedes aegypti and 2.7% (2) Aedes albopictus. A total of 1,170 Ae. aegypti and three Ae. albopictus was collected and 81 pools were generated. Although none of the Ae. albopictus pools were chikungunya virus (CHIKV)-positive, 18 Ae. aegypti pools (22.8%) contained CHIKV, yielding an infection rate of 32.3/1,000 mosquitoes. A lack of herd immunity in conjunction with high mosquito populations, poor vector control services in this region, and targeted collections in locations of human cases may explain the high infection rate in this vector. Consistent with predictions from experimental studies, Ae. aegypti appears to be the principal vector of CHIKV in southern Mexico, while the role of Ae. albopictus remains unknown.

  2. Genetic Diversity of Brazilian Aedes aegypti: Patterns following an Eradication Program

    PubMed Central

    Monteiro, Fernando A.; Shama, Renata; Martins, Ademir J.; Gloria-Soria, Andrea; Brown, Julia E.; Powell, Jeffrey R.

    2014-01-01

    Background Aedes aegypti is the most important vector of dengue fever in Brazil, where severe epidemics have recently taken place. Ae. aegypti in Brazil was the subject of an intense eradication program in the 1940s and 50s to control yellow fever. Brazil was the largest country declared free of this mosquito by the Pan-American Health Organization in 1958. Soon after relaxation of this program, Ae. aegypti reappeared in this country, and by the early 1980s dengue fever had been reported. The aim of this study is to analyze the present-day genetic patterns of Ae. aegypti populations in Brazil. Methodology/Principal Findings We studied the genetic variation in samples of 11 widely spread populations of Ae. aegypti in Brazil based on 12 well-established microsatellite loci. Our principal finding is that present-day Brazilian Ae. aegypti populations form two distinct groups, one in the northwest and one in the southeast of the country. These two groups have genetic affinities to northern South American countries and the Caribbean, respectively. This is consistent with what has been reported for other genetic markers such as mitochondrial DNA and allele frequencies at the insecticide resistance gene, kdr. Conclusions/Significance We conclude that the genetic patterns in present day populations of Ae. aegypti in Brazil are more consistent with a complete eradication of the species in the recent past followed by re-colonization, rather than the alternative possibility of expansion from residual pockets of refugia. At least two colonizations are likely to have taken place, one from northern South American countries (e.g., Venezuela) that founded the northwestern group, and one from the Caribbean that founded the southeastern group. The proposed source areas were never declared free of Ae. aegypti. PMID:25233218

  3. The Genetics of Chemoreception in the Labella and Tarsi of Aedes aegypti

    DTIC Science & Technology

    2014-01-01

    The genetics of chemoreception in the labella and tarsi of Aedes aegypti Jackson T. Sparks, Jonathan D. Bohbot, Joseph C. Dickens* United States...labella and tarsi of both sexes of adult Ae. aegypti and discuss their possible roles in the physiology and behavior of this important disease vector...Recently, Ionotropic Receptors have also been shown to play a role in DEET avoidance in D. melanogaster (Kain et al., 2013), highlighting the need to

  4. Effects of Irritant Chemicals on Aedes aegypti Resting Behavior: Is There a Simple Shift to Untreated "Safe Sites"?

    DTIC Science & Technology

    2011-07-26

    Effects of Irritant Chemicals on Aedes aegypti Resting Behavior: Is There a Simple Shift to Untreated ‘‘Safe Sites’’? Hortance Manda*, Luana M. Arce... aegypti to irritant and repellent chemicals that can be exploited to reduce man-vector contact. Maximum efficacy of interventions based on irritant...overall impact. Methods: Using a laboratory box assay, resting patterns of two population strains of female Ae. aegypti (THAI and PERU) were evaluated

  5. Mosquito-Borne Diseases and Omics: Salivary Gland Proteome of the Female Aedes aegypti Mosquito.

    PubMed

    Dhawan, Rakhi; Kumar, Manish; Mohanty, Ajeet Kumar; Dey, Gourav; Advani, Jayshree; Prasad, T S Keshava; Kumar, Ashwani

    2017-01-01

    The female Aedes aegypti mosquito is an important vector for several tropical and subtropical diseases such as dengue, chikungunya, and Zika and yellow fever. The disease viruses infect the mosquito and subsequently spread to the salivary glands after which the viruses can be transmitted to humans with probing or feeding by the mosquito. Omics systems sciences offer the opportunity to characterize vectors and can inform disease surveillance, vector control and development of innovative diagnostics, personalized medicines, vaccines, and insecticide targets. Using high-resolution mass spectrometry, we performed an analysis of the A. aegypti salivary gland proteome. The A. aegypti proteome resulted in acquisition of 83,836 spectra. Upon searches against the protein database of the A. aegypti, these spectra were assigned to 5417 unique peptides, belonging to 1208 proteins. To the best of our knowledge, this is the largest set of proteins identified in the A. aegypti salivary gland. Of note, 29 proteins were involved in immunity-related pathways in salivary glands. A subset of these proteins is known to interact with disease viruses. Another 15 proteins with signal cleavage site were found to be secretory in nature, and thus possibly playing critical roles in blood meal ingestion. These findings provide a baseline to advance our understanding of vector-borne diseases and vector-pathogen interactions before virus transmission in global health, and might therefore enable future design and development of virus-blocking strategies and novel molecular targets in the mosquito vector A. aegypti.

  6. Recent Changes in the Local Distribution of Aedes aegypti (Diptera: Culicidae) in South Florida, USA.

    PubMed

    Hopperstad, K A; Reiskind, M H

    2016-07-01

    Disease transmission is directly tied to the spatial distribution of disease vectors. The distribution of Aedes aegypti (L.) in the United States has diminished since the introduction of Aedes albopictus (Skuse) in the 1980s. However, Ae. aegypti persists in some urban areas, particularly in south Florida. The pattern of habitat segregation of these two species is well documented, but the consistency of this phenomenon over time is unknown. To examine the dynamics of the local distributions of these two species, we studied the spatial pattern of Ae. aegypti and Ae. albopictus over time at a fine landscape scale in Palm Beach County, FL. We compared patterns from 2006-2007 with their distributions in 2013, taking into account abiotic factors of microclimate and land cover. We found evidence for a local shift in Ae. aegypti distribution, but could not attribute this to changes in measured abiotic factors. Alternatively, the interaction between Ae. aegypti and Ae. albopictus that initially resulted Ae. aegypti decline may be being attenuated through natural selection. This study confirms the importance of monitoring the changing ranges of these two important vector species.

  7. Evidence for Aedes aegypti (Diptera: Culicidae) Oviposition on Boats in the Peruvian Amazon.

    PubMed

    Guagliardo, Sarah Anne; Morrison, Amy C; Luis Barboza, Jose; Wesson, Dawn M; Ponnusamy, Loganathan; Astete, Helvio; Vazquez-Prokopec, Gonzalo; Kitron, Uriel

    2015-07-01

    Dengue vector Aedes aegypti L. is invading peri-urban and rural areas throughout Latin America. Our previous research in the Peruvian Amazon has shown that river boats are heavily infested with immature and adult Ae. aegypti mosquitoes, likely playing a major role in their long-distance dispersal and successful invasion. However, the presence of immature mosquitoes provides no information about the timing of oviposition, and whether it took place in the boats. Here, we used baited ovitraps deployed on river boats to test the hypothesis that Ae. aegypti oviposition occurs during boat travel. We deployed 360 ovitraps on 60 different barges during August and October of 2013, and February 2014 (with 20 barges sampled during each month). We found that Ae. aegypti mosquitoes in 22 individual ovitraps from 15 of the 60 barges (premise index 25%) across all sampling dates. Further, the distribution of Ae. aegypti egg abundance was highly aggregated: 2.6% of traps (N=7) were responsible for 71.8% of eggs found, and 1.5% of traps (N=4) were responsible for all (100%) of the larvae found. Similarly, 5% of boats were responsible for the 71.47% of eggs. Our results provide strong evidence that Ae. aegypti oviposition commonly occurs during boat travel. Baited ovitraps could represent a cost-effective means of monitoring and controlling mosquito populations on boats.

  8. Conocimientos y autoeficacia asociados a la prevención del VIH y SIDA en mujeres chilenas

    PubMed Central

    Villegas Rodríguez, Natalia; Ferrer Lagunas, Lilian Marcela; Cianelli Acosta, Rosina; Miner, Sarah; Lara Campos, Loreto; Peragallo, Nilda

    2014-01-01

    Resumen Objetivo Evaluar la relación existente entre conocimientos y autoeficacia asociados al VIH/SIDA en mujeres chilenas en desventaja social. Metodología Estudio correlacional, que utiliza la medición basal del estudio “Testeando una intervención en VIH y SIDA en mujeres chilenas”, realizada entre 2006 y 2008, que tiene una muestra de 496 mujeres entre 18 y 49 años residentes en dos comunas de Santiago de Chile. Las participantes respondieron un cuestionario estructurado aplicado por entrevistadoras entrenadas. Este cuestionario incluyó preguntas sobre datos sociodemográficos, escala de conocimientos de conductas de riesgo y autoeficacia, entre otros. Resultados Edad promedio de 32.3±9.1 años, 72.2% vive con su pareja y 42.7% poseen educación media completa. La puntuación media de los conocimientos de la infección por el VIH fue de 8.9±2.5, mientras que para las tres escalas empleadas para medir autoeficacia fueron: “Normas de los pares” =9.8±3.6, “Intención de reducir conductas de riesgo” =12.2±3.6 y “Self Efficacy Form”=20.2±4.7. Los conocimientos tuvieron una correlación positiva débil con la “intención de reducir conductas de riesgo” (r=0.19; p<0.0001) y con la escala “Self Efficacy Form” (r=0.34; p<0.0001), pero no se relacionaron con las “normas de los pares en cuanto a relaciones sexuales seguras” (r=0.13; p=0.78). Conclusión Existe una débil correlación positiva entre el nivel de conocimientos sobre el VIH/SIDA y la autoeficacia en mujeres chilenas en desventaja social. PMID:25284914

  9. Soluciones analiticas AL problema de jets con velocidad de eyeccion variable EN EL tiempo.

    NASA Astrophysics Data System (ADS)

    Canto, J.; Raga, A. C.; D'Alessio, P.

    1998-11-01

    Se presenta un nuevo metodo que permite resolver de manera exacta y analitica las ecuaciones que describen un jet hipersonico con velocidad de eyeccion variable en el tiempo. El metodo se basa en consideraciones sencillas de conservacion de momento para las superficies de trabajo que se forman en el interior del jet. Como ejemplo, se presentan soluciones para jets con variacion sinusoidal en la velocidad de eyeccion, y tambien para el caso de un incremento lineal en el tiempo. Estas soluciones analiticas tienen una clara aplicacion en la interpretacion de las observaciones de jets asociados a objetos Herbig-Haro.

  10. Transcriptome analysis of Aedes aegypti transgenic mosquitoes with altered immunity.

    PubMed

    Zou, Zhen; Souza-Neto, Jayme; Xi, Zhiyong; Kokoza, Vladimir; Shin, Sang Woon; Dimopoulos, George; Raikhel, Alexander

    2011-11-01

    The mosquito immune system is involved in pathogen-elicited defense responses. The NF-κB factors REL1 and REL2 are downstream transcription activators of Toll and IMD immune pathways, respectively. We have used genome-wide microarray analyses to characterize fat-body-specific gene transcript repertoires activated by either REL1 or REL2 in two transgenic strains of the mosquito Aedes aegypti. Vitellogenin gene promoter was used in each transgenic strain to ectopically express either REL1 (REL1+) or REL2 (REL2+) in a sex, tissue, and stage specific manner. There was a significant change in the transcript abundance of 297 (79 up- and 218 down-regulated) and 299 (123 up- and 176 down-regulated) genes in fat bodies of REL1+ and REL2+, respectively. Over half of the induced genes had predicted functions in immunity, and a large group of these was co-regulated by REL1 and REL2. By generating a hybrid transgenic strain, which ectopically expresses both REL1 and REL2, we have shown a synergistic action of these NF-κB factors in activating immune genes. The REL1+ immune transcriptome showed a significant overlap with that of cactus (RNAi)-depleted mosquitoes (50%). In contrast, the REL2+ -regulated transcriptome differed from the relatively small group of gene transcripts regulated by RNAi depletion of a putative inhibitor of the IMD pathway, caspar (35 up- and 140 down-regulated), suggesting that caspar contributes to regulation of a subset of IMD-pathway controlled genes. Infections of the wild type Ae. aegypti with Plasmodium gallinaceum elicited the transcription of a distinct subset of immune genes (76 up- and 25 down-regulated) relative to that observed in REL1+ and REL2+ mosquitoes. Considerable overlap was observed between the fat body transcriptome of Plasmodium-infected mosquitoes and that of mosquitoes with transiently depleted PIAS, an inhibitor of the JAK-STAT pathway. PIAS gene silencing reduced Plasmodium proliferation in Ae. aegypti, indicating the

  11. Fundamentos para Asociados en Desarrollo Infantil quienes trabajan con Ninos Pequenos (Essentials for Child Development Associates Working with Young Children).

    ERIC Educational Resources Information Center

    Phillips, Carol Brunson, Ed.

    A study guide for the Child Development Associate (CDA) Professional Preparation Program, this Spanish-language guidebook contains essential information on the basics of good professional practice for early childhood educators. It includes self-study activities, checklists, and resources for additional information. Unit 1 provides an overview of…

  12. Developmental neurogenetics of sexual dimorphism in Aedes aegypti

    PubMed Central

    Duman-Scheel, Molly; Syed, Zainulabeuddin

    2015-01-01

    Sexual dimorphism, a poorly understood but crucial aspect of vector mosquito biology, encompasses sex-specific physical, physiological, and behavioral traits related to mosquito reproduction. The study of mosquito sexual dimorphism has largely focused on analysis of the differences between adult female and male mosquitoes, particularly with respect to sex-specific behaviors related to disease transmission. However, sexually dimorphic behaviors are the products of differential gene expression that initiates during development and therefore must also be studied during development. Recent technical advancements are facilitating functional genetic studies in the dengue vector Aedes aegypti, an emerging model for mosquito development. These methodologies, many of which could be extended to other non-model insect species, are facilitating analysis of the development of sexual dimorphism in neural tissues, particularly the olfactory system. These studies are providing insight into the neurodevelopmental genetic basis for sexual dimorphism in vector mosquitoes. PMID:26949699

  13. Repellents Inhibit P450 Enzymes in Stegomyia (Aedes) aegypti

    PubMed Central

    Jaramillo Ramirez, Gloria Isabel; Logan, James G.; Loza-Reyes, Elisa; Stashenko, Elena; Moores, Graham D.

    2012-01-01

    The primary defence against mosquitoes and other disease vectors is often the application of a repellent. Despite their common use, the mechanism(s) underlying the activity of repellents is not fully understood, with even the mode of action of DEET having been reported to be via different mechanisms; e.g. interference with olfactory receptor neurones or actively detected by olfactory receptor neurones on the antennae or maxillary palps. In this study, we discuss a novel mechanism for repellence, one of P450 inhibition. Thirteen essential oil extracts from Colombian plants were assayed for potency as P450 inhibitors, using a kinetic fluorometric assay, and for repellency using a modified World Health Organisation Pesticide Evaluations Scheme (WHOPES) arm-in cage assay with Stegomyia (Aedes) aegypti mosquitoes. Bootstrap analysis on the inhibition analysis revealed a significant correlation between P450-inhibition and repellent activity of the oils. PMID:23152795

  14. Resistance of Aedes aegypti to temephos and adaptive disadvantages

    PubMed Central

    Diniz, Morgana Michele Cavalcanti de Souza Leal; Henriques, Alleksandra Dias da Silva; Leandro, Renata da Silva; Aguiar, Dalvanice Leal; Beserra, Eduardo Barbosa

    2014-01-01

    OBJECTIVE To evaluate the resistance of Aedes aegypti to temephos Fersol 1G (temephos 1% w/w) associated with the adaptive disadvantage of insect populations in the absence of selection pressure. METHODS A diagnostic dose of 0.28 mg a.i./L and doses between 0.28 mg a.i./L and 1.40 mg a.i./L were used. Vector populations collected between 2007 and 2008 in the city of Campina Grande, state of Paraíba, were evaluated. To evaluate competition in the absence of selection pressure, insect populations with initial frequencies of 20.0%, 40.0%, 60.0%, and 80.0% resistant individuals were produced and subjected to the diagnostic dose for two months. Evaluation of the development of aquatic and adult stages allowed comparison of the life cycles in susceptible and resistant populations and construction of fertility life tables. RESULTS No mortality was observed in Ae. aegypti populations subjected to the diagnostic dose of 0.28 mg a.i./L. The decreased mortality observed in populations containing 20.0%, 40.0%, 60.0%, and 80.0% resistant insects indicates that temephos resistance is unstable in the absence of selection pressure. A comparison of the life cycles indicated differences in the duration and viability of the larval phase, but no differences were observed in embryo development, sex ratio, adult longevity, and number of eggs per female. CONCLUSIONS The fertility life table results indicated that some populations had reproductive disadvantages compared with the susceptible population in the absence of selection pressure, indicating the presence of a fitness cost in populations resistant to temephos. PMID:25372168

  15. Cumulative mortality of Aedes aegypti larvae treated with compounds

    PubMed Central

    Torres, Sandra Maria; da Cruz, Nadine Louise Nicolau; Rolim, Vitor Pereira de Matos; Cavalcanti, Maria Inês de Assis; Alves, Leucio Câmara; da Silva, Valdemiro Amaro

    2014-01-01

    OBJECTIVE To evaluate the larvicidal activity of Azadirachta indica, Melaleuca alternifolia, carapa guianensis essential oils and fermented extract of Carica papaya against Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae). METHODS The larvicide test was performed in triplicate with 300 larvae for each experimental group using the third larval stage, which were exposed for 24h. The groups were: positive control with industrial larvicide (BTI) in concentrations of 0.37 ppm (PC1) and 0.06 ppm (PC2); treated with compounds of essential oils and fermented extract, 50.0% concentration (G1); treated with compounds of essential oils and fermented extract, 25.0% concentration (G2); treated with compounds of essential oils and fermented extract, 12.5% concentration (G3); and negative control group using water (NC1) and using dimethyl (NC2). The larvae were monitored every 60 min using direct visualization. RESULTS No mortality occurred in experimental groups NC1 and NC2 in the 24h exposure period, whereas there was 100% mortality in the PC1 and PC2 groups compared to NC1 and NC2. Mortality rates of 65.0%, 50.0% and 78.0% were observed in the groups G1, G2 and G3 respectively, compared with NC1 and NC2. CONCLUSIONS The association between three essential oils from Azadirachta indica, Melaleuca alternifolia, Carapa guianensis and fermented extract of Carica papaya was efficient at all concentrations. Therefore, it can be used in Aedes aegypti Liverpool third larvae stage control programs. PMID:25119939

  16. The relationship between entomological indicators of Aedes aegypti abundance and dengue virus infection

    PubMed Central

    Stoddard, Steven T.; Barker, Christopher M.; Van Rie, Annelies; Messer, William B.; Meshnick, Steven R.; Morrison, Amy C.; Scott, Thomas W.

    2017-01-01

    Routine entomological monitoring data are used to quantify the abundance of Ae. aegypti. The public health utility of these indicators is based on the assumption that greater mosquito abundance increases the risk of human DENV transmission, and therefore reducing exposure to the vector decreases incidence of infection. Entomological survey data from two longitudinal cohort studies in Iquitos, Peru, linked with 8,153 paired serological samples taken approximately six months apart were analyzed. Indicators of Ae. aegypti density were calculated from cross-sectional and longitudinal entomological data collected over a 12-month period for larval, pupal and adult Ae. aegypti. Log binomial models were used to estimate risk ratios (RR) to measure the association between Ae. aegypti abundance and the six-month risk of DENV seroconversion. RRs estimated using cross-sectional entomological data were compared to RRs estimated using longitudinal data. Higher cross-sectional Ae. aegypti densities were not associated with an increased risk of DENV seroconversion. Use of longitudinal entomological data resulted in RRs ranging from 1.01 (95% CI: 1.01, 1.02) to 1.30 (95% CI: 1.17, 1.46) for adult stage density estimates and RRs ranging from 1.21 (95% CI: 1.07, 1.37) to 1.75 (95% CI: 1.23, 2.5) for categorical immature indices. Ae. aegypti densities calculated from longitudinal entomological data were associated with DENV seroconversion, whereas those measured cross-sectionally were not. Ae. aegypti indicators calculated from cross-sectional surveillance, as is common practice, have limited public health utility in detecting areas or populations at high risk of DENV infection. PMID:28333938

  17. Detritus type alters the outcome of interspecific competition between Aedes aegypti and Aedes albopictus (Diptera: Culicidae).

    PubMed

    Murrell, Ebony G; Juliano, Steven A

    2008-05-01

    Many studies of interspecific competition between Aedes albopictus (Skuse) and Aedes aegypti (L.) (Diptera: Culicidae) larvae show that Ae. albopictus are superior resource competitors to Ae. aegypti. Single-species studies indicate that growth and survival of Ae. albopictus and Ae. aegypti larvae are affected by the type of detritus present in containers, which presumably affects the amount and quality of microorganisms that the mosquito larvae consume. We tested whether different detritus types alter the intensity of larval competition by raising 10 different density/species combinations of Ae. albopictus and Ae. aegypti larvae under standard laboratory conditions, with one of four detritus types (oak, pine, grass, or insect) provided as a nutrient base. Intraspecific competitive effects on survival were present with all detritus types. Ae. albopictus survivorship was unaffected by interspecific competition in all treatments. Negative interspecific effects on Ae. aegypti survivorship were present with three of four detritus types, but absent with grass. Estimated finite rate of increase (lambda') was lower with pine detritus than with any other detritus type for both species. Furthermore, Ae. aegypti lambda' was negatively affected by high interspecific density in all detritus types except grass. Thus, our experiment confirms competitive asymmetry in favor of Ae. albopictus with oak, pine, or insect detritus, but also demonstrates that certain detritus types may eliminate interspecific competition among the larvae of these species, which may allow for stable coexistence. Such variation in competitive outcome with detritus type may help to account for observed patterns of coexistence/exclusion of Ae. albopictus and Ae. aegypti in the field.

  18. Ecological Modeling of Aedes aegypti (L.) Pupal Production in Rural Kamphaeng Phet, Thailand

    PubMed Central

    Aldstadt, Jared; Koenraadt, Constantianus J. M.; Fansiri, Thanyalak; Kijchalao, Udom; Richardson, Jason; Jones, James W.; Scott, Thomas W.

    2011-01-01

    Background Aedes aegypti (L.) is the primary vector of dengue, the most important arboviral infection globally. Until an effective vaccine is licensed and rigorously administered, Ae. aegypti control remains the principal tool in preventing and curtailing dengue transmission. Accurate predictions of vector populations are required to assess control methods and develop effective population reduction strategies. Ae. aegypti develops primarily in artificial water holding containers. Release recapture studies indicate that most adult Ae. aegypti do not disperse over long distances. We expect, therefore, that containers in an area of high development site density are more likely to be oviposition sites and to be more frequently used as oviposition sites than containers that are relatively isolated from other development sites. After accounting for individual container characteristics, containers more frequently used as oviposition sites are likely to produce adult mosquitoes consistently and at a higher rate. To this point, most studies of Ae. aegypti populations ignore the spatial density of larval development sites. Methodology Pupal surveys were carried out from 2004 to 2007 in rural Kamphaeng Phet, Thailand. In total, 84,840 samples of water holding containers were used to estimate model parameters. Regression modeling was used to assess the effect of larval development site density, access to piped water, and seasonal variation on container productivity. A varying-coefficients model was employed to account for the large differences in productivity between container types. A two-part modeling structure, called a hurdle model, accounts for the large number of zeroes and overdispersion present in pupal population counts. Findings The number of suitable larval development sites and their density in the environment were the primary determinants of the distribution and abundance of Ae. aegypti pupae. The productivity of most container types increased significantly as

  19. The relationship between entomological indicators of Aedes aegypti abundance and dengue virus infection.

    PubMed

    Cromwell, Elizabeth A; Stoddard, Steven T; Barker, Christopher M; Van Rie, Annelies; Messer, William B; Meshnick, Steven R; Morrison, Amy C; Scott, Thomas W

    2017-03-01

    Routine entomological monitoring data are used to quantify the abundance of Ae. aegypti. The public health utility of these indicators is based on the assumption that greater mosquito abundance increases the risk of human DENV transmission, and therefore reducing exposure to the vector decreases incidence of infection. Entomological survey data from two longitudinal cohort studies in Iquitos, Peru, linked with 8,153 paired serological samples taken approximately six months apart were analyzed. Indicators of Ae. aegypti density were calculated from cross-sectional and longitudinal entomological data collected over a 12-month period for larval, pupal and adult Ae. aegypti. Log binomial models were used to estimate risk ratios (RR) to measure the association between Ae. aegypti abundance and the six-month risk of DENV seroconversion. RRs estimated using cross-sectional entomological data were compared to RRs estimated using longitudinal data. Higher cross-sectional Ae. aegypti densities were not associated with an increased risk of DENV seroconversion. Use of longitudinal entomological data resulted in RRs ranging from 1.01 (95% CI: 1.01, 1.02) to 1.30 (95% CI: 1.17, 1.46) for adult stage density estimates and RRs ranging from 1.21 (95% CI: 1.07, 1.37) to 1.75 (95% CI: 1.23, 2.5) for categorical immature indices. Ae. aegypti densities calculated from longitudinal entomological data were associated with DENV seroconversion, whereas those measured cross-sectionally were not. Ae. aegypti indicators calculated from cross-sectional surveillance, as is common practice, have limited public health utility in detecting areas or populations at high risk of DENV infection.

  20. Vector Competence of Aedes aegypti and Aedes polynesiensis Populations from French Polynesia for Chikungunya Virus

    PubMed Central

    Richard, Vaea; Paoaafaite, Tuterarii; Cao-Lormeau, Van-Mai

    2016-01-01

    Background From October 2014 to March 2015, French Polynesia experienced for the first time a chikungunya outbreak. Two Aedes mosquitoes may have contributed to chikungunya virus (CHIKV) transmission in French Polynesia: the worldwide distributed Ae. aegypti and the Polynesian islands-endemic Ae. polynesiensis mosquito. Methods To investigate the vector competence of French Polynesian populations of Ae. aegypti and Ae. polynesiensis for CHIKV, mosquitoes were exposed per os at viral titers of 7 logs tissue culture infectious dose 50%. At 2, 6, 9, 14 and 21 days post-infection (dpi), saliva was collected from each mosquito and inoculated onto C6/36 mosquito cells to check for the presence of CHIKV infectious particles. Legs and body (thorax and abdomen) of each mosquito were also collected at the different dpi and submitted separately to viral RNA extraction and CHIKV real-time RT-PCR. Results CHIKV infection rate, dissemination and transmission efficiencies ranged from 7–90%, 18–78% and 5–53% respectively for Ae. aegypti and from 39–41%, 3–17% and 0–14% respectively for Ae. polynesiensis, depending on the dpi. Infectious saliva was found as early as 2 dpi for Ae. aegypti and from 6 dpi for Ae. polynesiensis. Our laboratory results confirm that the French Polynesian population of Ae. aegypti is highly competent for CHIKV and they provide clear evidence for Ae. polynesiensis to act as an efficient CHIKV vector. Conclusion As supported by our findings, the presence of two CHIKV competent vectors in French Polynesia certainly contributed to enabling this virus to quickly disseminate from the urban/peri-urban areas colonized by Ae. aegypti to the most remote atolls where Ae. polynesiensis is predominating. Ae. polynesiensis was probably involved in the recent chikungunya outbreaks in Samoa and the Cook Islands. Moreover, this vector may contribute to the risk for CHIKV to emerge in other Polynesian islands like Fiji, and more particularly Wallis where there

  1. Genome Investigations of Vector Competence in Aedes aegypti to Inform Novel Arbovirus Disease Control Approaches.

    PubMed

    Severson, David W; Behura, Susanta K

    2016-10-30

    Dengue (DENV), yellow fever, chikungunya, and Zika virus transmission to humans by a mosquito host is confounded by both intrinsic and extrinsic variables. Besides virulence factors of the individual arboviruses, likelihood of virus transmission is subject to variability in the genome of the primary mosquito vector, Aedes aegypti. The "vectorial capacity" of A. aegypti varies depending upon its density, biting rate, and survival rate, as well as its intrinsic ability to acquire, host and transmit a given arbovirus. This intrinsic ability is known as "vector competence". Based on whole transcriptome analysis, several genes and pathways have been predicated to have an association with a susceptible or refractory response in A. aegypti to DENV infection. However, the functional genomics of vector competence of A. aegypti is not well understood, primarily due to lack of integrative approaches in genomic or transcriptomic studies. In this review, we focus on the present status of genomics studies of DENV vector competence in A. aegypti as limited information is available relative to the other arboviruses. We propose future areas of research needed to facilitate the integration of vector and virus genomics and environmental factors to work towards better understanding of vector competence and vectorial capacity in natural conditions.

  2. Oviposition and Embryotoxicity of Indigofera suffruticosa on Early Development of Aedes aegypti (Diptera: Culicidae).

    PubMed

    Vieira, Jeymesson Raphael Cardoso; Leite, Roberta Maria Pereira; Lima, Izabela Rangel; Navarro, Daniela do Amaral Ferraz; Bianco, Everson Miguel; Leite, Sônia Pereira

    2012-01-01

    Aqueous extract of Indigofera suffruticosa leaves obtained by infusion was used to evaluate the oviposition, its effect on development of eggs and larvae, and morphological changes in larvae of Aedes aegypti. The bioassays were carried out with aqueous extract in different concentrations on eggs, larvae, and female mosquitoes, and the morphological changes were observed in midgut of larvae. The extract showed repellent activity on A. aegypti mosquitoes, reducing significantly the egg laying by females with control substrate (343 (185-406)) compared with the treated substrate (88 (13-210)). No eclosion of A. aegypti eggs at different concentrations studied was observed. The controleclodedin 35%. At concentration of 250 μg/mL, 93.3% of larvae remained in the second instar of development and at concentrations of 500, 750, and 1000 μg/mL the inhibitory effect was lower with percentages of 20%, 53.3%, and 46.6%, respectively. Morphological changes like disruption on the peritrophic envelope (PE), discontinued underlying epithelium, increased gut lumen, and segments with hypertrophic aspects were observed in anterior region of medium midgut of larvae of A. aegypti. The results showed repellent activity, specific embryotoxicity, and general growth retardation in A. aegypti by medium containing aqueous extract of I. suffruticosa leaves.

  3. Indoor Resting Behavior of Aedes aegypti (Diptera: Culicidae) in Acapulco, Mexico.

    PubMed

    Dzul-Manzanilla, Felipe; Ibarra-López, Jésus; Bibiano Marín, Wilbert; Martini-Jaimes, Andrés; Leyva, Joel Torres; Correa-Morales, Fabián; Huerta, Herón; Manrique-Saide, Pablo; Prokopec, Gonzalo Vazquez M

    2016-12-22

    The markedly anthropophilic and endophilic behaviors of Aedes aegypti (L.) make it a very efficient vector of dengue, chikungunya, and Zika viruses. Although a large body of research has investigated the immature habitats and conditions for adult emergence, relatively few studies have focused on the indoor resting behavior and distribution of vectors within houses. We investigated the resting behavior of Ae. aegypti indoors in 979 houses of the city of Acapulco, Mexico, by performing exhaustive indoor mosquito collections to describe the rooms and height at which mosquitoes were found resting. In total, 1,403 adult and 747 female Ae. aegypti were collected, primarily indoors (98% adults and 99% females). Primary resting locations included bedrooms (44%), living rooms (25%), and bathrooms (20%), followed by kitchens (9%). Aedes aegypti significantly rested below 1.5 m of height (82% adults, 83% females, and 87% bloodfed females); the odds of finding adult Ae. aegypti mosquitoes below 1.5 m was 17 times higher than above 1.5 m. Our findings provide relevant information for the design of insecticide-based interventions selectively targeting the adult resting population, such as indoor residual spraying.

  4. Population dynamics of Aedes aegypti from a dengue hyperendemic urban setting in Colombia.

    PubMed

    Ocampo, Clara B; Wesson, Dawn M

    2004-10-01

    This study evaluated if the Aedes aegypti population in the city of Cali, Colombia was composed of genetically distinct local populations with different levels of insecticide resistance and dengue vector competence. Insecticide resistance was assayed biochemically and was associated with varying levels of mixed-function oxidases and non-specific esterases. The genes encoding those enzymes were under selective pressure from insecticides used to suppress Ae. aegypti populations. Vector competence showed heterogeneity among the vector populations ranging from 19% to 60%. Population genetic analysis of random amplified polymorphic DNA-polymerase chain reaction products, expressed as genetic distance, Wright's F(st), and migration rate (Nm), demonstrated moderate genetic differentiation among Ae. aegypti from four sites (F(st) = 0.085). The results from all characteristics evaluated in the study demonstrated spatial and temporal variation between Ae. aegypti populations. At any specific time, the local populations of Ae. aegypti were genetically differentiated and unique with respect to insecticide resistance and vector competence. Both characteristics changed independently.

  5. QTL Mapping of Genome Regions Controlling Temephos Resistance in Larvae of the Mosquito Aedes aegypti

    PubMed Central

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

    2014-01-01

    Introduction 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. Methodology/Principal Findings 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. Conclusions/Significance Temephos resistance is under the control of many metabolic genes of small effect and dispersed throughout the Ae. aegypti genome. PMID:25330200

  6. Oviposition and Embryotoxicity of Indigofera suffruticosa on Early Development of Aedes aegypti (Diptera: Culicidae)

    PubMed Central

    Vieira, Jeymesson Raphael Cardoso; Leite, Roberta Maria Pereira; Lima, Izabela Rangel; Navarro, Daniela do Amaral Ferraz; Bianco, Everson Miguel; Leite, Sônia Pereira

    2012-01-01

    Aqueous extract of Indigofera suffruticosa leaves obtained by infusion was used to evaluate the oviposition, its effect on development of eggs and larvae, and morphological changes in larvae of Aedes aegypti. The bioassays were carried out with aqueous extract in different concentrations on eggs, larvae, and female mosquitoes, and the morphological changes were observed in midgut of larvae. The extract showed repellent activity on A. aegypti mosquitoes, reducing significantly the egg laying by females with control substrate (343 (185–406)) compared with the treated substrate (88 (13–210)). No eclosion of A. aegypti eggs at different concentrations studied was observed. The controleclodedin 35%. At concentration of 250 μg/mL, 93.3% of larvae remained in the second instar of development and at concentrations of 500, 750, and 1000 μg/mL the inhibitory effect was lower with percentages of 20%, 53.3%, and 46.6%, respectively. Morphological changes like disruption on the peritrophic envelope (PE), discontinued underlying epithelium, increased gut lumen, and segments with hypertrophic aspects were observed in anterior region of medium midgut of larvae of A. aegypti. The results showed repellent activity, specific embryotoxicity, and general growth retardation in A. aegypti by medium containing aqueous extract of I. suffruticosa leaves. PMID:21822443

  7. Evidence of limited polyandry in a natural population of Aedes aegypti.

    PubMed

    Richardson, Joshua B; Jameson, Samuel B; Gloria-Soria, Andrea; Wesson, Dawn M; Powell, Jeffrey

    2015-07-01

    The mosquito Aedes aegypti is a vector of yellow fever, dengue, and chikungunya. Control of the insect is crucial to stop the spread of dengue and chikungunya, so it is critically important to understand its mating behavior. Primarily, based on laboratory behavior, it has long been assumed that Ae. aegypti females mate once in their lifetime. However, multiple inseminations have been observed in semi-field and laboratory settings, and in closely related species. Here, we report the first evidence of polyandry in a natural population of Ae. aegypti. Female Ae. aegypti were captured around the New Orleans, LA, metropolitan area. They were offered a blood meal and allowed to lay eggs, which were reared to the third-instar larval stage. A parentage analysis using four microsatellite loci was performed. Out of 48 families, 3 showed evidence of multiple paternity. An expanded analysis of these three families found that one family group included offspring contributed by three fathers, and the other two included offspring from two fathers. This result establishes that polyandry can occur in a small proportion of Ae. aegypti females in a natural setting. This could complicate future genetic control efforts and has implications for sampling for population genetics.

  8. Comparison of the insecticide susceptibilities of laboratory strains of Aedes aegypti and Aedes albopictus.

    PubMed

    Gómez, Andrea; Seccacini, Emilia; Zerba, Eduardo; Licastro, Susana

    2011-12-01

    A susceptible strain of Aedes albopictus derived from the Gainesville strain (Florida, USA) was established in our laboratory. The larvicidal efficacies of the neurotoxic insecticides temephos, permethrin and the pure cis and trans-permethrin isomers and the microbial insecticide Bacillus thuringiensis israelensis (Bti) against Ae. albopictus were estimated and compared to a susceptible strain of Aedes aegypti. The larvicidal effect of insect growth regulator pyriproxyfen was also evaluated in both mosquito strains. The median lethal concentration/median emergency inhibition values for Ae. aegypti and Ae. albopictus, respectively, were: temephos, 3.058 and 6.632 ppb, permethrin, 3.143 and 4.933 ppb, cis-permethrin, 4.457 and 10.068 ppb, trans-permethrin, 1.510 and 3.883 ppb, Bti, 0.655 and 0.880 ppb and pyriproxyfen, 0.00774 and 0.01642 ppb. Ae. albopictus was more tolerant than Ae. aegypti to all six larvicides evaluated. The order of susceptibility for Ae. aegypti was pyriproxyfen > Bti > trans-permethrin > temephos > permethrin > cis-permethrin and for Ae. albopictus was pyriproxyfen > Bti > trans-permethrin > permethrin > temephos > cis-permethrin. Because both species can be found together in common urban, suburban and rural breeding sites, the results of this work provide baseline data on the susceptibility of Ae. albopictus to insecticides commonly used for controlling Ae. aegypti in the field.

  9. Heat Sensitivity of wMel Wolbachia during Aedes aegypti Development.

    PubMed

    Ulrich, Jill N; Beier, John C; Devine, Gregor J; Hugo, Leon E

    2016-07-01

    The wMel strain of Wolbachia bacteria is known to prevent dengue and Zika virus transmission in the mosquito vector Aedes aegypti. Accordingly, the release of wMel-infected A. aegypti in endemic regions has been recommended by the World Health Organization as a potential strategy for controlling dengue and Zika outbreaks. However, the utility of this approach could be limited if high temperatures in the aquatic habitats where A. aegypti develop are detrimental to Wolbachia. We exposed wMel-infected A. aegypti eggs and larvae to fluctuating daily temperatures of 30-40°C for three, five, or seven days during their development. We found that Wolbachia levels in females emerging from heat treatments were significantly lower than in the controls that had developed at 20-30°C. Notably, seven days of high temperatures starting at the egg stage reduced Wolbachia levels in emerging females to less than 0.1% of the wMel control levels. However, after adult females returned to 20-30°C for 4-7 days, they experienced differing degrees of Wolbachia recovery. Our findings suggest that the spread of Wolbachia in wild A. aegypti populations and any consequent protection from dengue and Zika viruses might be limited in ecosystems that experience periods of extreme heat, but Wolbachia levels recover partially after temperatures return to normal.

  10. Human and environmental factors affecting Aedes aegypti distribution in an arid urban environment.

    PubMed

    Walker, Kathleen R; Joy, Teresa K; Ellers-Kirk, Christa; Ramberg, Frank B

    2011-06-01

    Aedes aegypti has reappeared in urban communities in the southwestern U.S.A. in the 1990s after a 40-year absence. In 2003 and 2004, a systematic survey was conducted throughout metropolitan Tucson, AZ, to identify human and environmental factors associated with Ae. aegypti distribution within an arid urban area. Aedes aegypti presence and abundance were measured monthly using the Centers for Disease Control and Prevention enhanced oviposition traps at sampling sites established in a grid at 3- to 4-km intervals across the city. Sampling occurred in the summer rainy season (July through September), the peak of mosquito activity in the region. Multiple regression analyses were conducted to determine relationships between mosquito density and factors that could influence mosquito distribution. House age was the only factor that showed a consistent significant association with Ae. aegypti abundance in both years: older houses had more mosquito eggs. This is the 1st study of Ae. aegypti distribution at a local level to identify house age as an explanatory factor independent of other human demographic factors. Further research into the reasons why mosquitoes were more abundant around older homes may help inform and refine future vector surveillance and control efforts in the event of a dengue outbreak in the region.

  11. Heat Sensitivity of wMel Wolbachia during Aedes aegypti Development

    PubMed Central

    Beier, John C.; Devine, Gregor J.; Hugo, Leon E.

    2016-01-01

    The wMel strain of Wolbachia bacteria is known to prevent dengue and Zika virus transmission in the mosquito vector Aedes aegypti. Accordingly, the release of wMel-infected A. aegypti in endemic regions has been recommended by the World Health Organization as a potential strategy for controlling dengue and Zika outbreaks. However, the utility of this approach could be limited if high temperatures in the aquatic habitats where A. aegypti develop are detrimental to Wolbachia. We exposed wMel-infected A. aegypti eggs and larvae to fluctuating daily temperatures of 30–40°C for three, five, or seven days during their development. We found that Wolbachia levels in females emerging from heat treatments were significantly lower than in the controls that had developed at 20–30°C. Notably, seven days of high temperatures starting at the egg stage reduced Wolbachia levels in emerging females to less than 0.1% of the wMel control levels. However, after adult females returned to 20–30°C for 4–7 days, they experienced differing degrees of Wolbachia recovery. Our findings suggest that the spread of Wolbachia in wild A. aegypti populations and any consequent protection from dengue and Zika viruses might be limited in ecosystems that experience periods of extreme heat, but Wolbachia levels recover partially after temperatures return to normal. PMID:27459519

  12. Local Evolution of Pyrethroid Resistance Offsets Gene Flow Among Aedes aegypti Collections in Yucatan State, Mexico

    PubMed Central

    Saavedra-Rodriguez, Karla; Beaty, Meaghan; Lozano-Fuentes, Saul; Denham, Steven; Garcia-Rejon, Julian; Reyes-Solis, Guadalupe; Machain-Williams, Carlos; Loroño-Pino, Maria Alba; Flores-Suarez, Adriana; Ponce-Garcia, Gustavo; Beaty, Barry; Eisen, Lars; Black, William C.

    2015-01-01

    The mosquito Aedes aegypti is the major vector of the four serotypes of dengue virus (DENV1–4). Previous studies have shown that Ae. aegypti in Mexico have a high effective migration rate and that gene flow occurs among populations that are up to 150 km apart. Since 2000, pyrethroids have been widely used for suppression of Ae. aegypti in cities in Mexico. In Yucatan State in particular, pyrethroids have been applied in and around dengue case households creating an opportunity for local selection and evolution of resistance. Herein, we test for evidence of local adaptation by comparing patterns of variation among 27 Ae. aegypti collections at 13 single nucleotide polymorphisms (SNPs): two in the voltage-gated sodium channel gene para known to confer knockdown resistance, three in detoxification genes previously associated with pyrethroid resistance, and eight in putatively neutral loci. The SNPs in para varied greatly in frequency among collections, whereas SNPs at the remaining 11 loci showed little variation supporting previous evidence for extensive local gene flow. Among Ae. aegypti in Yucatan State, Mexico, local adaptation to pyrethroids appears to offset the homogenizing effects of gene flow. PMID:25371186

  13. Differentiation of Aedes aegypti and Aedes notoscriptus (Diptera: Culicidae) eggs using scanning electron microscopy.

    PubMed

    Faull, Katherine J; Williams, Craig R

    2016-05-01

    Aedes notoscriptus and Aedes aegypti are both peri-domestic, invasive container-breeding mosquitoes. While the two potential arboviral vectors are bionomically similar, their sympatric distribution in Australia is limited. In this study, analyses of Ae. aegypti and Ae. notoscriptus eggs were enabled using scanning electron microscopy. Significant variations in egg length to width ratio and outer chorionic cell field morphology between Ae. aegypti and Ae. notoscriptus enabled distinction of the two species. Intraspecific variations in cell field morphology also enabled differentiation of the separate populations of both species, highlighting regional and global variation. Our study provides a comprehensive comparative analysis of inter- and intraspecific egg morphological and morphometric variation between two invasive container-breeding mosquitoes. The results indicate a high degree of intraspecific variation in Ae. notoscriptus egg morphology when compared to the eggs of Ae. aegypti. Comparative morphological analyses of Ae. aegypti and Ae. notoscriptus egg attributes using SEM allows differentiation of the species and may be helpful in understanding egg biology in relation to biotope of origin.

  14. Susceptibility of Florida Aedes aegypti and Aedes albopictus to dengue viruses from Puerto Rico.

    PubMed

    Alto, Barry W; Smartt, Chelsea T; Shin, Dongyoung; Bettinardi, David; Malicoate, Jolene; Anderson, Sheri L; Richards, Stephanie L

    2014-12-01

    Locally acquired dengue cases in the continental U.S. are rare. However, outbreaks of dengue-1 during 2009, 2010, and 2013 in Florida and dengue-1 and -2 in Texas suggest vulnerability to transmission. Travel and commerce between Puerto Rico and the U.S. mainland is common, which may pose a risk for traveler-imported dengue cases. Mosquitoes were collected in Florida and used to evaluate their susceptibility to dengue viruses (DENV) from Puerto Rico. Aedes aegypti and Ae. albopictus were susceptible to virus infection with DENV-1 and -2. No significant differences were observed in rates of midgut infection or dissemination between Ae. aegypti or Ae. albopictus for DENV-1 (6-14%). Aedes aegypti was significantly more susceptible to midgut infection with DENV-2 than Ae. albopictus (Ae. aegypti, ∼28%; Ae. albopictus, ∼9%). The dissemination rate with dengue-2 virus for Ae. aegypti (23%) was greater than Ae. albopictus (0%), suggesting that Ae. albopictus is not likely to be an important transmitter of the DENV-2 isolate from Puerto Rico. These results are discussed in light of Florida's vulnerability to DENV transmission.

  15. [Ecology of Aedes aegypti and Aedes albopictus in the Americas and disease transmission].

    PubMed

    Rey, Jorge R; Lounibos, Philip

    2015-01-01

    The recent range expansion of the mosquito Aedes albopictus has been associated in some areas by declines in abundance or local elimination of Aedes aegypti, but the two species still coexist in large regions of the Americas. We offer a summary of the possible mechanisms responsible for the abundance and displacement pattern observed and of their significance in terms of disease transmission. Among these mechanisms we may mention the competition for limiting resources, the differences in the ability to withstand starvation, the apparent competition through differential effects of the parasite Ascogregarina taiwanensis, and the inhibition of Ae. aegypti egg development by Ae. albopictus larvae. Habitat segregation has been proposed as a mechanism promoting the coexistence of the two species through avoidance of direct competition. Aedes aegypti predominates in urban areas, Ae. albopictus in rural ones, and both species coexist in the suburbs. There is also evidence that in certain areas, habitat segregation in terms of distance from the coast can influence the distribution of both species. Another possible cause of the rapid disappearance of Ae. aegypti is reproductive interference between the species. According to this hypothesis, asymmetric effects of interspecific mating favor Ae. albopictus. This type of reproductive interference can result in the elimination of sympatric populations of the affected species and can be one of the major causes for the swiftness with which Ae. aegypti disappeared from some places in the Americas following invasions by Ae. albopictus.

  16. Changing Domesticity of Aedes aegypti in Northern Peninsular Malaysia: Reproductive Consequences and Potential Epidemiological Implications

    PubMed Central

    Saifur, Rahman G. M.; Dieng, Hamady; Hassan, Ahmad Abu; Salmah, Md Rawi Che; Satho, Tomomitsu; Miake, Fumio; Hamdan, Ahmad

    2012-01-01

    Background The domestic dengue vector Aedes aegypti mosquitoes breed in indoor containers. However, in northern peninsular Malaysia, they show equal preference for breeding in both indoor and outdoor habitats. To evaluate the epidemiological implications of this peridomestic adaptation, we examined whether Ae. aegypti exhibits decreased survival, gonotrophic activity, and fecundity due to lack of host availability and the changing breeding behavior. Methodology/Principal Findings This yearlong field surveillance identified Ae. aegypti breeding in outdoor containers on an enormous scale. Through a sequence of experiments incorporating outdoors and indoors adapting as well as adapted populations, we observed that indoors provided better environment for the survival of Ae. aegypti and the observed death patterns could be explained on the basis of a difference in body size. The duration of gonotrophic period was much shorter in large-bodied females. Fecundity tended to be greater in indoor acclimated females. We also found increased tendency to multiple feeding in outdoors adapted females, which were smaller in size compared to their outdoors breeding counterparts. Conclusion/Significance The data presented here suggest that acclimatization of Ae. aegypti to the outdoor environment may not decrease its lifespan or gonotrophic activity but rather increase breeding opportunities (increased number of discarded containers outdoors), the rate of larval development, but small body sizes at emergence. Size is likely to be correlated with disease transmission. In general, small size in Aedes females will favor increased blood-feeding frequency resulting in higher population sizes and disease occurrence. PMID:22363516

  17. Genome Investigations of Vector Competence in Aedes aegypti to Inform Novel Arbovirus Disease Control Approaches

    PubMed Central

    Severson, David W.; Behura, Susanta K.

    2016-01-01

    Dengue (DENV), yellow fever, chikungunya, and Zika virus transmission to humans by a mosquito host is confounded by both intrinsic and extrinsic variables. Besides virulence factors of the individual arboviruses, likelihood of virus transmission is subject to variability in the genome of the primary mosquito vector, Aedes aegypti. The “vectorial capacity” of A. aegypti varies depending upon its density, biting rate, and survival rate, as well as its intrinsic ability to acquire, host and transmit a given arbovirus. This intrinsic ability is known as “vector competence”. Based on whole transcriptome analysis, several genes and pathways have been predicated to have an association with a susceptible or refractory response in A. aegypti to DENV infection. However, the functional genomics of vector competence of A. aegypti is not well understood, primarily due to lack of integrative approaches in genomic or transcriptomic studies. In this review, we focus on the present status of genomics studies of DENV vector competence in A. aegypti as limited information is available relative to the other arboviruses. We propose future areas of research needed to facilitate the integration of vector and virus genomics and environmental factors to work towards better understanding of vector competence and vectorial capacity in natural conditions. PMID:27809220

  18. Myco-synthesis of silver nanoparticles using Beauveria bassiana against dengue vector, Aedes aegypti (Diptera: Culicidae).

    PubMed

    Banu, A Najitha; Balasubramanian, C

    2014-08-01

    The efficacy of silver synthesized biolarvicide with the help of entomopathogenic fungus, Beauveria bassiana, was assessed against the different larval instars of dengue vector, Aedes aegypti. The silver nanoparticles were observed and characterized by a scanning electron microscope (SEM) and energy-dispersive X-ray (EDX). A surface plasmon resonance band was observed at 420 nm in UV-vis spectrophotometer. The characterization was confirmed by shape (spherical), size 36.88-60.93 nm, and EDX spectral peak at 3 keV of silver nanoparticles. The synthesized silver nanoparticles have been tested against the different larval instars of Ae. aegypti at different concentrations for a period of 24 h. Ae. aegypti larvae were found more susceptible to the synthesized silver nanoparticles. The LC50 and LC90 values are 0.79 and 1.09 ppm with respect to the Ae. aegypti treated with B. bassiana (Bb) silver nanoparticles (AgNPs). First and second instar larvae of Ae. aegypti have shown cent percent mortality while third and fourth instars found 50.0, 56.6, 70.0, 80.0, and 86.6 and 52.4, 60.0, 68.5, 76.0, and 83.3% mortality at 24 h of exposure in 0.06 and 1.00 ppm, respectively. It is suggested that the entomopathogenic fungus synthesized silver nanoparticles would be appropriate for environmentally safer and greener approach for new leeway in vector control strategy through a biological process.

  19. Chemicals isolated from Justicia adhatoda Linn reduce fitness of the mosquito, Aedes aegypti L.

    PubMed

    Thanigaivel, Annamalai; Senthil-Nathan, Sengottayan; Vasantha-Srinivasan, Prabhakaran; Edwin, Edward-Sam; Ponsankar, Athirstam; Selin-Rani, Selvaraj; Pradeepa, Venkatraman; Chellappandian, Muthiah; Kalaivani, Kandaswamy; Abdel-Megeed, Ahmed; Narayanan, Raman; Murugan, Kadarkarai

    2017-04-01

    Extracts from Justicia adhatoda L. (Acanthaceae) strongly reduced the fitness of the mosquito, Aedes aegypti Linn. The methanolic extracts inhibited several enzymes responsible for protecting insects from oxidative and other damage, including glutathione-S-transferase, superoxide dismutase, cytochrome P450, and α- and β-esterases. They increased repellency (maximum repellency at 100 ppm) in host-seeking adult females using the "arm-in cage assay." Histopathological examination showed the extracts led to serious midgut cell damage. Justicia adhatoda extracts led to reduced fecundity and oviposition of gravid females compared to controls. The extracts led to substantially reduced A. aegypti survival. We infer that the extracts have potential to reduce pathogen transmission by suppressing population growth of A. aegypti, and possibly other mosquito species.

  20. The Drosophila melanogaster cinnabar gene is a cell autonomous genetic marker in Aedes aegypti (Diptera: Culicidae).

    PubMed

    Sethuraman, Nagaraja; O'Brochta, David A

    2005-07-01

    The cinnabar gene of Drosophila melanogaster (Meigen) encodes for kynurenine hydroxylase, an enzyme involved in ommochrome biosynthesis. This gene is commonly included as a visible genetic marker in gene vectors used to create transgenic Aedes aegypti (L.) that are homozygous for the khw allele, the mosquito homolog of cinnabar. Unexpectedly, the phenotype of cells expressing kynurenine hydroxylase in transgenic Ae. aegypti is cell autonomous as demonstrated by the recovery of insects heterozygous for the kynurenine hydroxylase transgene with mosaic eye color patterns. In addition, a transgenic gynandromorph was recovered in which one-half of the insect was expressing the kynurenine hydroxylase transgene, including one eye with red pigmentation, whereas the other half of the insect was homozygous khw and included a white eye. The cell autonomous behavior of cinnabar in transgenic Ae. aegypti is unexpected and increases the utility of this genetic marker.

  1. An evaluation of some Trinidadian plant extracts against larvae of Aedes aegypti mosquitoes.

    PubMed

    Mohammed, Azad; Chadee, Dave D

    2007-06-01

    In recent times, bioprospecting for plants that show bioactive properties has yielded many chemicals that can be used in controlling mosquitoes. Crude extracts of 4 terrestrial and 3 mangrove plants were assayed against 2-3 larval instars of Aedes aegypti. Among the plants tested, Cordia curassavica showed the highest levels of activity for all the extracts tested. Azadirachta indica showed the least activity, whereas the 2 cultivars of Mangifera indica showed substantial activity for the aqueous extracts. The mangrove species proved to be relatively nontoxic to Ae. aegypti larvae when compared to the terrestrial plants. The results of this study suggest that some common plants in Trinidad may be highly effective in controlling the urban vector of yellow fever and dengue fever, Ae. aegypti.

  2. Sustained, Area-Wide Control of Aedes aegypti Using CDC Autocidal Gravid Ovitraps

    PubMed Central

    Barrera, Roberto; Amador, Manuel; Acevedo, Verónica; Hemme, Ryan R.; Félix, Gilberto

    2014-01-01

    We have shown that the Centers for Disease Control and Prevention (CDC) autocidal gravid ovitraps (AGO trap) reduced the Aedes aegypti population and prevented mosquito outbreaks in southern Puerto Rico. After showing treatment efficacy for 1 year, we deployed three traps per home in an area that formerly did not have traps and in a site that served as the intervention area. Two new areas were selected as reference sites to compare the density of Ae. aegypti without traps. We monitored mosquitoes and weather every week in all four sites. The hypotheses were the density of Ae. aegypti in the former reference area converges to the low levels observed in the intervention area, and mosquito density in both areas having control traps is lower than in the new reference areas. Mosquito density in the former reference area decreased 79% and mosquito density in the new reference areas was 88% greater than in the intervention areas. PMID:25223937

  3. Effect of bioactive fractions of Citrullus vulgaris Schrad. leaf extract against Anopheles stephensi and Aedes aegypti.

    PubMed

    Mullai, K; Jebanesan, A; Pushpanathan, T

    2008-04-01

    The benzene extract of Citrullus vulgaris was tested against Anopheles stephensi and Aedes aegypti for the larvicidal activity and ovicidal properties. The crude benzene extract was found to be more effective against A. stephensi than A. aegypti. The LC50 values were 18.56 and 42.76 ppm respectively. The LC50 values for silica gel fractions (bioactive fractions I, II, III and IV) were 11.32, 14.12, 14.53 and 16.02 ppm respectively. The mean per cent hatchability of the egg rafts were observed after 48 h post treatment. The crude extract of benzene exerted 100% mortality at 250 ppm against A. stephensi and at 300 ppm against A. aegypti. The silica gel fractions I and II afforded 100% mortality at 100 ppm and III and IV exerted the hatchability rate of 4.9 and 5.3% at the same concentration against A. stephensi.

  4. Sustained, area-wide control of Aedes aegypti using CDC autocidal gravid ovitraps.

    PubMed

    Barrera, Roberto; Amador, Manuel; Acevedo, Verónica; Hemme, Ryan R; Félix, Gilberto

    2014-12-01

    We have shown that the Centers for Disease Control and Prevention (CDC) autocidal gravid ovitraps (AGO trap) reduced the Aedes aegypti population and prevented mosquito outbreaks in southern Puerto Rico. After showing treatment efficacy for 1 year, we deployed three traps per home in an area that formerly did not have traps and in a site that served as the intervention area. Two new areas were selected as reference sites to compare the density of Ae. aegypti without traps. We monitored mosquitoes and weather every week in all four sites. The hypotheses were the density of Ae. aegypti in the former reference area converges to the low levels observed in the intervention area, and mosquito density in both areas having control traps is lower than in the new reference areas. Mosquito density in the former reference area decreased 79% and mosquito density in the new reference areas was 88% greater than in the intervention areas.

  5. Solution structure of FK506-binding protein 12 from Aedes aegypti.

    PubMed

    Chakraborty, Goutam; Shin, Joon; Nguyen, Quoc Toan; Harikishore, Amaravadhi; Baek, Kwanghee; Yoon, Ho Sup

    2012-10-01

    Dengue remains one of the major public concerns as the virus eludes the immune response. Currently, no vaccines or antiviral therapeutics are available for dengue prevention or treatment. Immunosuppressive drug FK506 shows an antimalarial activity, and its molecular target, FK506-binding protein (FKBP), was identified in human Plasmodium parasites. Likewise, a conserved FKBP family protein has also been identified in Aedes aegypti (AaFKBP12), which is expected to play a similar role in the life cycle of Aedes aegypti, the primary vector of dengue virus infection. As FKBPs belong to a highly conserved class of immunophilin family and are involved in key biological regulations, they are considered as attractive pharmacological targets. In this study, we have determined the nuclear magnetic resonance solution structure of AaFKBP12, a novel FKBP member from Aedes aegypti, and presented its structural features, which may facilitate the design of potential inhibitory ligands against the dengue-transmitting mosquitoes.

  6. Temporal and geographic patterns of Aedes aegypti (Diptera: Culicidae) production in Iquitos, Peru.

    PubMed

    Morrison, Amy C; Gray, Kenneth; Getis, Arthur; Astete, Helvio; Sihuincha, Moises; Focks, Dana; Watts, Douglas; Stancil, Jeffrey D; Olson, James G; Blair, Patrick; Scott, Thomas W

    2004-11-01

    Large-scale longitudinal cohort studies are necessary to characterize temporal and geographic variation in Aedes aegypti (L.) (Diptera: Culicidae) production patterns and to develop targeted dengue control strategies that will reduce disease. We carried out pupal/demographic surveys in a circuit of approximately 6,000 houses, 10 separate times, between January 1999 and August 2002 in the Amazonian city of Iquitos, Peru. We quantified the number of containers positive for Ae. aegypti larvae and/or pupae, containers holding pupae, and the absolute number of pupae by 4-mo sampling circuits and spatially by geographic area by using a geographic information system developed for the city. A total of 289,941 water-holding containers were characterized, of which 7.3% were positive for Ae. aegypti. Temporal and geographic variations were detected for all variables examined, and the relative importance of different container types for production of Ae. aegypti was calculated. Ae. aegypti larvae and pupae were detected in 64 types of containers. Consistent production patterns were observed for the lid status (lids: 32% wet containers, 2% pupal production), container location (outdoor: 43% wet containers, 85% pupal production), and method by which the container was filled with water (rain filled: 15% wet containers, 88.3% pupal production); these patterns were consistent temporally and geographically. We describe a new container category (nontraditional) that includes transient puddles, which were rare but capable of producing large numbers of pupae. Because of high variable pupal counts, four container categories (large tank, medium storage, miscellaneous, and nontraditional) should be targeted in addition to outdoor rain-filled containers that are not covered by a lid. The utility of targeted Ae. aegypti control is discussed, as well as the ability to achieve control objectives based on published but untested threshold values.

  7. Contact Irritant Responses of Aedes aegypti Using Sublethal Concentration and Focal Application of Pyrethroid Chemicals

    PubMed Central

    Manda, Hortance; Shah, Pankhil; Polsomboon, Suppaluck; Chareonviriyaphap, Theeraphap; Castro-Llanos, Fanny; Morrison, Amy; Burrus, Roxanne G.; Grieco, John P.; Achee, Nicole L.

    2013-01-01

    Background Previous studies have demonstrated contact irritant and spatial repellent behaviors in Aedes aegypti following exposure to sublethal concentrations of chemicals. These sublethal actions are currently being evaluated in the development of a push-pull strategy for Ae. aegypti control. This study reports on mosquito escape responses after exposure to candidate chemicals for a contact irritant focused push-pull strategy using varying concentrations and focal application. Methods Contact irritancy (escape) behavior, knockdown and 24 hour mortality rates were quantified in populations of female Ae. aegypti under laboratory conditions and validated in the field (Thailand and Peru) using experimental huts. Evaluations were conducted using varying concentrations and treatment surface area coverage (SAC) of three pyrethroid insecticides: alphacypermethrin, lambacyhalothrin and deltamethrin. Results Under laboratory conditions, exposure of Ae. aegypti to alphacypermethrin using the standard field application rate (FAR) resulted in escape responses at 25% and 50% SAC that were comparable with escape responses at 100% SAC. Significant escape responses were also observed at <100% SAC using ½FAR of all test compounds. In most trials, KD and 24 hour mortality rates were higher in mosquitoes that did not escape than in those that escaped. In Thailand, field validation studies indicated an early time of exit (by four hours) and 40% increase in escape using ½FAR of alphacypermethrin at 75% SAC compared to a matched chemical-free control. In Peru, however, the maximum increase in Ae. aegypti escape from alphacypermethrin-treated huts was 11%. Conclusions/Significance Results presented here suggest a potential role for sublethal and focal application of contact irritant chemicals in an Ae. aegypti push-pull strategy to reduce human–vector contact inside treated homes. However, the impact of an increase in escape response on dengue virus transmission is currently unknown

  8. The risk of Aedes aegypti breeding and premises condition in South Mexico.

    PubMed

    Manrique-Saide, Pablo; Davies, Clive R; Coleman, Paul G; Che-Mendoza, Azael; Dzul-Manzanilla, Felipe; Barrera-Pérez, Mario; Hernández-Betancourt, Silvia; Ayora-Talavera, Guadalupe; Pinkus-Rendón, Miguel; Burciaga-Zúñiga, Pierre; Sánchez Tejeda, Gustavo; Arredondo-Jiménez, Juan I

    2013-12-01

    A recent innovation instrumented for the Dengue Prevention and Control program in Mexico is the use of the premises condition index (PCI) as an indicator of risk for the vector Aedes aegypti infestation in dengue-endemic localities of Mexico. This paper addresses whether further improvements for the dengue control program could be made if the prevalence and productivity of Ae. aegypti populations could be reliably predicted using PCI at the household level, as well as medium-sized neighborhoods. We evaluated the use of PCI to predict the infestation with Aedes aegypti (breeding sites and immature productivity) in Merida, Mexico. The study consisted of a cross-sectional survey based on a cluster-randomized sampling design. We analyzed the statistical association between Aedes infestation and PCI, the extent to which the 3 components of PCI (house maintenance, and tidiness and shading of the patio) contributed to the association between PCI and infestation and whether infestation in a given premises was also affected by the PCI of the surrounding ones. Premises with the lowest PCI had significantly lower Aedes infestation and productivity; and as PCI scores increased infestation levels also tended to increase. Household PCI was significantly associated with Ae. aegypti breeding, largely due to the effect of patio untidiness and patio shade. The mean PCI within the surroundings premises also had a significant and independent explanatory power to predict the risk for infestation, in addition to individual PCI. This is the 1st study in Mexico showing evidence that premises condition as measured by the PCI is related to Ae. aegypti breeding sites and immature productivity. Results suggest that PCI could be used to streamline surveys to inform control efforts at least where Ae. aegypti breeds outdoors, as in Merida. The effect of individual premises, neighborhood condition, and the risk of Aedes infestation imply that the risk for dengue vector infestation can only be

  9. Intriguing olfactory proteins from the yellow fever mosquito, Aedes aegypti

    NASA Astrophysics Data System (ADS)

    Ishida, Yuko; Chen, Angela M.; Tsuruda, Jennifer M.; Cornel, Anthon J.; Debboun, Mustapha; Leal, Walter S.

    2004-09-01

    Four antennae-specific proteins (AaegOBP1, AaegOBP2, AaegOBP3, and AaegASP1) were isolated from the yellow fever mosquito, Aedes aegypti and their full-length cDNAs were cloned. RT-PCR indicated that they are expressed in female and, to a lesser extent, in male antennae, but not in control tissues (legs). AaegOBP1 and AaegOBP3 showed significant similarity to previously identified mosquito odorant-binding proteins (OBPs) in cysteine spacing pattern and sequence. Two of the isolated proteins have a total of eight cysteine residues. The similarity of the spacing pattern of the cysteine residues and amino acid sequence to those of previously identified olfactory proteins suggests that one of the cysteine-rich proteins (AaegOBP2) is an OBP. The other (AaegASP1) did not belong to any group of known OBPs. Structural analyses indicate that six of the cysteine residues in AaegOBP2 are linked in a similar pattern to the previously known cysteine pairing in OBPs, i.e., Cys-24 Cys-55, Cys-51 Cys-104, Cys-95 Cys-113. The additional disulfide bridge, Cys-38 Cys-125, knits the extended C-terminal segment of the protein to a predicted α2-helix. As indicated by circular dichroism (CD) spectra, the extra rigidity seems to prevent the predicted formation of a C-terminal α-helix at low pH.

  10. Oviposition response of Aedes aegypti mosquitoes to different concentrations of hay infusion in Trinidad, West Indies.

    PubMed

    Chadee, D D; Lakhan, A; Ramdath, W R; Persad, R C

    1993-09-01

    Ovitraps containing various concentrations of hay infusion and tap water were exposed weekly in the field for 15 wk to determine the oviposition patterns of Aedes aegypti. The results showed 10, 20, 60 and 80% hay infusions each attracted similar numbers of Ae. aegypti eggs oviposited and egg occurrences. No repellent effect was observed. In another field study, significantly more eggs and egg occurrences were collected from 25 and 50% hay infusions and tap water. The differences in these results from those of a previous study in Puerto Rico are discussed.

  11. Detection of Aedes aegypti, Aedes albopictus, and Aedes koreicus in the Area of Sochi, Russia.

    PubMed

    Ganushkina, Ludmila A; Patraman, Ivan V; Rezza, Giovanni; Migliorini, Luigi; Litvinov, Serguei K; Sergiev, Vladimir P

    2016-01-01

    Following the identification of Aedes (Ae.) aegypti in the Sochi area in Russia at the beginning of 2000, entomological surveys were conducted during the summers of 2007, 2011, and 2012, leading to the identification of Ae. albopictus and Ae. koreicus. These findings highlight Russia as being the only country in the World Health Organization European Region with a documented presence of both Ae. aegypti and Ae. albopictus mosquitoes. Both mosquito species are found on the coasts of the Black Sea. Control measures are needed to reduce the possible risks of importing exotic vector-borne infections, such as dengue and chikungunya.

  12. Identification of Aedes aegypti and its Respective Life Stages by Real-Time PCR

    DTIC Science & Technology

    2004-06-01

    RTO-MP-HFM-108 22 - 1 Identification of Aedes aegypti and its Respective Life Stages by Real - Time PCR James C. McAvin1*; Major David E...Stages by Real - Time PCR 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK...grade water Identification of Aedes aegypti and its Respective Life Stages by Real - Time PCR RTO-MP-HFM-108 22 - 3 for no template controls

  13. Population genetic structure of the dengue mosquito Aedes aegypti in Venezuela.

    PubMed

    Herrera, Flor; Urdaneta, Ludmel; Rivero, José; Zoghbi, Normig; Ruiz, Johanny; Carrasquel, Gabriela; Martínez, José Antonio; Pernalete, Martha; Villegas, Patricia; Montoya, Ana; Rubio-Palis, Yasmin; Rojas, Elina

    2006-09-01

    The mosquito Aedes aegypti is the main vector of dengue in Venezuela. The genetic structure of this vector was investigated in 24 samples collected from eight geographic regions separated by up to 1160 km. We examined the distribution of a 359-basepair region of the NADH dehydrogenase subunit 4 mitochondrial gene among 1144 Ae. aegypti from eight collections. This gene was amplified by the polymerase chain reaction and tested for variation using single strand conformation polymorphism analysis. Seven haplotypes were detected throughout Venezuela and these were sorted into two clades. Significant differentiation was detected among collections and these were genetically isolated by distance.

  14. Finding Aedes aegypti in a natural breeding site in an urban zone, Sao Paulo, Southeastern Brazil

    PubMed Central

    Lima-Camara, Tamara Nunes; Urbinatti, Paulo Roberto; Chiaravalloti-Neto, Francisco

    2016-01-01

    ABSTRACT This is the description of how nine Aedes aegypti larvae were found in a natural breeding site in the Pinheiros neighborhood, city of Sao Paulo, SP, Southeastern Brazil. The record was conducted in December 2014, during an entomological surveillance program of dengue virus vectors, with an active search of potential breeding sites, either artificial or natural. Finding Ae. aegypti larvae in a tree hole shows this species’ ability to use both artificial and natural environments as breeding sites and habitats, which points towards the importance of maintaining continuous surveillance on this mosquito in all kinds of water-holding containers. PMID:26982959

  15. Influence of the Length of Storage on Aedes aegypti (Diptera: Culicidae) Egg Viability.

    PubMed

    Brown, Heidi E; Smith, Caitlin; Lashway, Stephanie

    2016-12-22

    Aedes aegypti (L.) is one of the most important arboviral vectors worldwide. Vector control is targeted at immature and adult stages; however, eggs are resistant to desiccation and may repopulate treated areas long after treatment ceases. We investigated the effect of age on Ae. aegypti egg hatching rates using newly colonized populations (F2) from an arid region. We found a strongly negative association where older eggs had lower hatch rates. The capacity of eggs to survive for long periods of time has implications on mosquito control. In addition, the accumulation of eggs in containers should be accounted for in abundance modeling efforts where populations may grow rapidly early in the season.

  16. Intermolecular interaction of thiosemicarbazone derivatives to solvents and a potential Aedes aegypti target

    NASA Astrophysics Data System (ADS)

    da Silva, João Bosco P.; Hallwass, Fernando; da Silva, Aluizio G.; Moreira, Diogo Rodrigo; Ramos, Mozart N.; Espíndola, José Wanderlan P.; de Oliveira, Ana Daura T.; Brondani, Dalci José; Leite, Ana Cristina L.; Merz, Kenneth M.

    2015-08-01

    DFT calculations were used to access information about structure, energy and electronic properties of series of phenyl- and phenoxymethyl-(thio)semicarbazone derivatives with demonstrated activity against the larvae of Aedes aegypti in stage L4. The way as the thiosemicarbazone derivatives can interact with solvents like DMSO and water were analyzed from the comparison between calculated and experimental 1H NMR chemical shifts. The evidences of thiosemicarbazone derivatives making H-bond interaction to solvent have provide us insights on how they can interact with a potential A. aegypti's biological target, the Sterol Carrier Protein-2.

  17. Methods for TALEN evaluation, use, and mutation detection in the mosquito Aedes aegypti

    PubMed Central

    Basu, Sanjay; Aryan, Azadeh; Haac, Mary Etna; Myles, Kevin M.; Adelman, Zach N.

    2016-01-01

    The generation and study of transgenic Aedes aegypti mosquitoes provides an essential tool for elucidating the complex molecular biology of this important vector. Within the field, genetic manipulation has now surpassed the proof of principle stage and is now utilised in both applied and theoretical vector control strategies. The application of new instruments, technologies and techniques allows ever more controlled experiments to be conducted. In this text we describe microinjection of Ae. aegypti embryos in the context of evaluating and performing genomic editing with transcription activator-like effector nucleases (TALENs). PMID:26443221

  18. Geographic distribution of Aedes aegypti and Aedes albopictus collected from used tires in Vietnam.

    PubMed

    Higa, Yukiko; Yen, Nguyen Thi; Kawada, Hitoshi; Son, Tran Hai; Hoa, Nguyen Thuy; Takagi, Masahiro

    2010-03-01

    The spatial distribution of Aedes aegypti and Aedes albopictus in environmental and geographical zones, e.g., urban-rural, coastal-mountainous, and north-south, was investigated throughout Vietnam. Immature stages were collected from used tires along roads. The effects of regions, seasons, and the degree of urbanization on the density and the frequency were statistically analyzed. Aedes aegypti predominated in the southern and central regions, while Ae. albopictus predominated in the northern region, which may be related to climatic conditions (temperature and rainfall). Larval collection from used tires may be suitable to assess rapidly the current distribution of dengue mosquitoes for estimating health risks and implementing vector control measures.

  19. The Sublethal Effects of the Entomopathic Fungus Leptolegnia chapmanii on Some Biological Parameters of the Dengue Vector Aedes aegypti

    PubMed Central

    Pelizza, S.A.; Scorsetti, A.C.; Tranchida, M.C.

    2013-01-01

    The mosquito Aedes aegypti (L.) (Diptera: Culicidae) is the primary vector of dengue in the Americas. The use of chemical insecticides is recommended during outbreaks of dengue in order to reduce the number of adult mosquitoes; however, because Ae. aegypti is highly synanthropic, the use of insecticides in densely populated areas is a dangerous practice. Leptolegnia chapmanii Seymour (Straminipila: Peronosporomycetes) is an entomopathogenic microorganism that has demonstrated marked pathogenicity toward the larvae of a number of mosquito species, with little or no effect on non-target insects. Therefore, the purpose of this study was to determine the sublethal effects of L. chapmanii on fecundity, number of gonotrophic cycles, fertility, and relationship between wing length and fecundity in Ae. aegypti females. Ae. aegypti females that survived infection with L. chapmanii laid fewer eggs, had a smaller number of gonotrophic cycles, had shorter wings, and were less fertile than controls. This is the first study on the sublethal effects experienced by specimens of Ae. aegypti that survived infection with zoospores of L. chapmanii. Although field studies should be carried out, the results obtained in this study are encouraging because the high and rapid larval mortality caused by L. chapmanii coupled with the reduction of reproductive capacity in Ae. aegypti females seem to cause a significant reduction in the number of adults in the mid and long term, thereby reducing the health risks associated with Ae. aegypti. PMID:23901823

  20. Development and evaluation of a pyriproxyfen-treated device to control the dengue vector, Aedes aegypti (L.) (Diptera:Culicidae).

    PubMed

    Ponlawat, Alongkot; Fansiri, Thanyalak; Kurusarttra, Somwang; Pongsiri, Arissara; McCardle, Patrick W; Evans, Brian P; Evans, Brain P; Richardson, Jason H

    2013-03-01

    The resurgence of dengue fever and the chikungunya epidemic make the control of Aedes aegypti mosquitoes, the vectors of these diseases, critically important. We developed and evaluated an Ae. aegypti control device that is visually-attractive to mosquitoes. This pyriproxyfen-treated device was evaluated for its impact on Ae. aegypti egg production and population dynamics in dengue-endemic areas in Thailand. The device consists of a "high rise" shaped ovitrap/ resting station covered with black cotton cloth. The device is easily collapsible and transportable. Ae. aegypti are generally drawn towards darker, shadier areas making this device physically attractive as a resting station to mosquitoes of all physiological stages. The results show this device suppressed Ae. aegypti populations after it was introduced into a village. The observed effect was primarily the result of the Ae. aegypti exposure to pyriproxyfen shortly after adult emergence or after taking a blood meal resulting in decreased egg production. We believe the device may be further improved physically and the formulation should be replaced to provide even better efficacy for controlling Ae. aegypti mosquito, populations.

  1. Aedes aegypti (Diptera: Culicidae) in Mauritania: First Report on the Presence of the Arbovirus Mosquito Vector in Nouakchott.

    PubMed

    Mint Lekweiry, Khadijetou; Ould Ahmedou Salem, Mohamed Salem; Ould Brahim, Khyarhoum; Ould Lemrabott, Mohamed Aly; Brengues, Cécile; Faye, Ousmane; Simard, Frédéric; Ould Mohamed Salem Boukhary, Ali

    2015-07-01

    Aedes aegypti L. (Diptera: Culicidae) is a major vector of yellow fever, dengue, and chikungunya viruses throughout tropical and subtropical areas of the world. Although the southernmost part of Mauritania along the Senegal river has long been recognized at risk of yellow fever transmission, Aedes spp. mosquitoes had never been reported northwards in Mauritania. Here, we report the first observation of Aedes aegypti aegypti (L.) and Aedes (Ochlerotatus) caspius (Pallas, 1771) in the capital city, Nouakchott. We describe the development sites in which larvae of the two species were found, drawing attention to the risk for emergence of arbovirus transmission in the city.

  2. Aedes aegypti salivary gland extract ameliorates experimental inflammatory bowel disease.

    PubMed

    Sales-Campos, Helioswilton; de Souza, Patricia Reis; Basso, Paulo José; Ramos, Anderson Daniel; Nardini, Viviani; Chica, Javier Emílio Lazo; Capurro, Margareth Lara; Sá-Nunes, Anderson; de Barros Cardoso, Cristina Ribeiro

    2015-05-01

    Current therapies for inflammatory bowel disease (IBD) are not totally effective, resulting in persistent and recurrent disease for many patients. Mosquito saliva contains immunomodulatory molecules and therein could represent a novel therapy for IBD. Here, we demonstrated the therapeutic activity of salivary gland extract (SGE) of Aedes aegypti on dextran sulfate sodium (DSS)-induced colitis. For this purpose, C57BL/6 male mice were exposed to 3% DSS in drinking water and treated with SGE at early (days 3-5) or late (days 5-8) time points, followed by euthanasia on days 6 and 9, respectively, for sample collection. The results showed an improvement in clinical disease outcome and postmortem scores after SGE treatment, accompanied by the systemic reduction in peripheral blood lymphocytes, with no impact on bone marrow and mesenteric lymph nodes cellularity or macrophages toxicity. Moreover, a local diminishment of IFN-γ, TNF-α, IL-1β and IL-5 cytokines together with a reduction in the inflammatory area were observed in the colon of SGE-treated mice. Strikingly, early treatment with SGE led to mice protection from a late DSS re-challenging, as observed by decreased clinical and postmortem scores, besides reduced circulating lymphocytes, indicating that the mosquito saliva may present components able to prevent disease relapse. Indeed, high performance liquid chromatography (HPLC) experiments pointed to a major SGE pool fraction (F3) able to ameliorate disease signs. In conclusion, SGE and its components might represent a source of important immunomodulatory molecules with promising therapeutic activity for IBD.

  3. Crystal structures of Aedes aegypti alanine glyoxylate aminotransferase.

    PubMed

    Han, Qian; Robinson, Howard; Gao, Yi Gui; Vogelaar, Nancy; Wilson, Scott R; Rizzi, Menico; Li, Jianyong

    2006-12-01

    Mosquitoes are unique in having evolved two alanine glyoxylate aminotransferases (AGTs). One is 3-hydroxykynurenine transaminase (HKT), which is primarily responsible for catalyzing the transamination of 3-hydroxykynurenine (3-HK) to xanthurenic acid (XA). Interestingly, XA is used by malaria parasites as a chemical trigger for their development within the mosquito. This 3-HK to XA conversion is considered the major mechanism mosquitoes use to detoxify the chemically reactive and potentially toxic 3-HK. The other AGT is a typical dipteran insect AGT and is specific for converting glyoxylic acid to glycine. Here we report the 1.75A high-resolution three-dimensional crystal structure of AGT from the mosquito Aedes aegypti (AeAGT) and structures of its complexes with reactants glyoxylic acid and alanine at 1.75 and 2.1A resolution, respectively. This is the first time that the three-dimensional crystal structures of an AGT with its amino acceptor, glyoxylic acid, and amino donor, alanine, have been determined. The protein is dimeric and adopts the type I-fold of pyridoxal 5-phosphate (PLP)-dependent aminotransferases. The PLP co-factor is covalently bound to the active site in the crystal structure, and its binding site is similar to those of other AGTs. The comparison of the AeAGT-glyoxylic acid structure with other AGT structures revealed that these glyoxylic acid binding residues are conserved in most AGTs. Comparison of the AeAGT-alanine structure with that of the Anopheles HKT-inhibitor complex suggests that a Ser-Asn-Phe motif in the latter may be responsible for the substrate specificity of HKT enzymes for 3-HK.

  4. An in vitro bioassay for the quantitative evaluation of mosquito repellents against Stegomyia aegypti (=Aedes aegypti) mosquitoes using a novel cocktail meal.

    PubMed

    Huang, T-H; Tien, N-Y; Luo, Y-P

    2015-09-01

    To assess the efficacy of new insect repellents, an efficient and safe in vitro bioassay system using a multiple-membrane blood-feeding device and a cocktail meal was developed. The multiple-membrane blood-feeding device facilitates the identification of new insect repellents by the high-throughput screening of candidate chemicals. A cocktail meal was developed as a replacement for blood for feeding females of Stegomyia aegypti (=Aedes aegypti) (L.) (Diptera: Culicidae). The cocktail meal consisted of a mixture of salt, albumin and dextrose, to which adenosine triphosphate was added to induce engorging. Feeding rates of St. aegypti on the cocktail meal and pig blood, respectively, did not differ significantly, but were significantly higher than the feeding rate on citrate phosphate dextrose-adenine 1 (CPDA-1) solutions, which had been used to replace bloodmeals in previous repellent assays. Dose-dependent biting inhibition rates were analysed using probit analysis. The RD(50) (the dose producing 50% repellence of mosquito feeding) values of DEET, citronella, carvacrol, geraniol, eugenol and thymol were 1.62, 14.40, 22.51, 23.29, 23.83 and 68.05 µg/cm(2), respectively.

  5. Insecticidal action of sodium anacardate from Brazilian cashew nut shell liquid against Aedes aegypti.

    PubMed

    Farias, Davi F; Cavalheiro, Mariana G; Viana, Sayonara M; De Lima, Glauber P G; da Rocha-Bezerra, Lady Clarissa B; Ricardo, Nágila M P S; Carvalho, Ana F U

    2009-09-01

    Aedes aegypti is the major vector of 1 of the most concerning arboviruses of the world, the dengue fever. The only effective way of reducing the incidence of dengue fever is to control the vector mosquito, mainly by application of insecticides to its breeding places. This study was aimed at assessing the insecticidal activity of sodium anacardate, isolated from Brazilian cashew nut shell liquid (CNSL), against the eggs, 3rd instars or pupae of Ae. aegypti. In addition, the acute toxicity of sodium anacardate to mice was also investigated. Sodium anacardate showed toxicity against Ae. aegypti eggs (median effective concentration [EC50] = 162.93 +/- 29.93 microg/ml), larvae (median lethal concentration [LC50] = 55.47 +/- 3.0 microg/ml) and pupae (LC50 = 369.78 - 52.30 microg/ml). On the other hand, even at high dose (0.3 g/kg body weight), this compound did not cause any adverse effects on mice, suggesting that this compound is safe to mammals. Therefore, sodium anacardate may be a viable low-cost alternative to help combat Ae. aegypti.

  6. Discriminating lethal concentrations and efficacy of six pyrethroids for control of Aedes aegypti in Thailand.

    PubMed

    Juntarajumnong, Waraporn; Pimnon, Sunthorn; Bangs, Michael J; Thanispong, Kanutcharee; Chareonviriyaphap, Theeraphap

    2012-03-01

    Establishing baseline insecticide discriminating doses is crucial in accurately determining susceptibility status and changing temporal patterns of physiological response in mosquito populations. Pyrethroids are the predominant chemicals used for controlling adult Aedes aegypti and Ae. albopictus, both vectors of dengue viruses, in Thailand. Presently, only 2 pyrethroids, permethrin and lambda-cyhalothrin, have published diagnostic dose rates for monitoring Ae. aegypti. This study established the diagnostic lethal concentrations for 6 different pyrethroids available in Thailand for dengue vector control. United States Department of Agriculture insecticide-susceptible strain of Ae. aegypti was used to establish the baseline concentrations for subsequent susceptibility testing of field populations. Our findings showed lower discriminating concentrations for lambda-cyhalothrin and permethrin than those recommended by the World Health Organization (WHO), at 2.5- and 1.7-fold lower dosing, respectively. The susceptibility status of 3 different geographical populations of field-collected Ae. aegypti were tested using the standard WHO procedures. All 3 field strains demonstrated varying levels of physiological resistance to each compound. We conclude that establishing the baseline diagnostic concentration of an insecticide is of paramount importance in accurately determining the susceptibility status in field-collected mosquitoes. If possible, discriminating doses should be established for all insecticides and test assays run concurrently with a known susceptible strain for more accurate monitoring of resistance in mosquito populations in Thailand.

  7. The Dengue Virus Mosquito Vector Aedes aegypti at High Elevation in México

    PubMed Central

    Lozano-Fuentes, Saul; Hayden, Mary H.; Welsh-Rodriguez, Carlos; Ochoa-Martinez, Carolina; Tapia-Santos, Berenice; Kobylinski, Kevin C.; Uejio, Christopher K.; Zielinski-Gutierrez, Emily; Monache, Luca Delle; Monaghan, Andrew J.; Steinhoff, Daniel F.; Eisen, Lars

    2012-01-01

    México has cities (e.g., México City and Puebla City) located at elevations > 2,000 m and above the elevation ceiling below which local climates allow the dengue virus mosquito vector Aedes aegypti to proliferate. Climate warming could raise this ceiling and place high-elevation cities at risk for dengue virus transmission. To assess the elevation ceiling for Ae. aegypti and determine the potential for using weather/climate parameters to predict mosquito abundance, we surveyed 12 communities along an elevation/climate gradient from Veracruz City (sea level) to Puebla City (∼2,100 m). Ae. aegypti was commonly encountered up to 1,700 m and present but rare from 1,700 to 2,130 m. This finding extends the known elevation range in México by > 300 m. Mosquito abundance was correlated with weather parameters, including temperature indices. Potential larval development sites were abundant in Puebla City and other high-elevation communities, suggesting that Ae. aegypti could proliferate should the climate become warmer. PMID:22987656

  8. Serratia odorifera a Midgut Inhabitant of Aedes aegypti Mosquito Enhances Its Susceptibility to Dengue-2 Virus

    PubMed Central

    Apte-Deshpande, Anjali; Paingankar, Mandar; Gokhale, Mangesh D.; Deobagkar, Dileep N.

    2012-01-01

    Mosquito midgut plays a crucial role in its vector susceptibility and pathogen interaction. Identification of the sustainable microflora of the midgut environment can therefore help in evaluating its contribution in mosquito-pathogen interaction and in turn vector competence. To understand the bacterial diversity in the midgut of Aedes aegypti mosquitoes, we conducted a screening study of the gut microbes of these mosquitoes which were either collected from fields or reared in the laboratory “culture-dependent” approach. This work demonstrated that the microbial flora of larvae and adult Ae. aegypti midgut is complex and is dominated by Gram negative proteobacteria. Serratia odorifera was found to be stably associated in the midguts of field collected and laboratory reared larvae and adult females. The potential influence of this sustainable gut microbe on DENV-2 susceptibility of this vector was evaluated by co-feeding S. odorifera with DENV-2 to adult Ae. aegypti females (free of gut flora). The observations revealed that the viral susceptibility of these Aedes females enhanced significantly as compared to solely dengue-2 fed and another gut inhabitant, Microbacterium oxydans co-fed females. Based on the results of this study we proposed that the enhancement in the DENV-2 susceptibility of Ae. aegypti females was due to blocking of prohibitin molecule present on the midgut surface of these females by the polypeptide of gut inhabitant S. odorifera. PMID:22848375

  9. Attracted to the enemy: Aedes aegypti prefers oviposition sites with predator-killed conspecifics.

    PubMed

    Albeny-Simões, Daniel; Murrell, Ebony G; Elliot, Simon L; Andrade, Mateus R; Lima, Eraldo; Juliano, Steven A; Vilela, Evaldo F

    2014-06-01

    Oviposition habitat choices of species with aquatic larvae are expected to be influenced by both offspring risk of mortality due to predation, and offspring growth potential. Aquatic predators may indirectly influence growth potential for prey by reducing prey density and, for filter-feeding prey, by increasing bacterial food for prey via added organic matter (feces, partially eaten victims), creating the potential for interactive effects on oviposition choices. We tested the hypothesis that the mosquito Aedes aegypti preferentially oviposits in habitats with predatory Toxorhynchites larvae because of indirect effects of predation on chemical cues indicating bacterial abundance. We predicted that A. aegypti would avoid oviposition in sites with Toxorhynchites, but prefer to oviposit where bacterial food for larvae is abundant, and that predation by Toxorhynchites would increase bacterial abundances. Gravid A. aegypti were offered paired oviposition sites representing choices among: predator presence; the act of predation; conspecific density; dead conspecific larvae; and bacterial activity. A. aegypti preferentially oviposited in sites with Toxorhynchites theobaldi predation, and with killed conspecific larvae, but failed to detect preferences for other treatments. The antibiotic tetracycline eliminated the strongest oviposition preference. Both predation by Toxorhynchites and killed larvae increased bacterial abundances, suggesting that oviposition attraction is cued by bacteria. Our results show the potential for indirect effects, like trophic cascades, to influence oviposition choices and community composition in aquatic systems. Our results suggest that predators like Toxorhynchites may be doubly beneficial as biocontrol agents because of the attraction of ovipositing mosquitoes to bacterial by-products of Toxorhynchites feeding.

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

    PubMed

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

    2008-04-01

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

  11. Comparative study of four membranes for evaluation of new insect/arthropod repellents using Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four different membranes: Baudruche; Hemotek, sausage, and silicone-based membrane were evaluated as human skin substitute for an in vitro repellent study using Aedes aegypti. No significant difference was observed in repellent activity (ED50) of DEET among the membranes. Sausage membrane was selec...

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

    PubMed Central

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

    2014-01-01

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

  13. Changes in host-seeking behavior of Puerto Rican Aedes aegypti (L.) following colonization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of colonization on host-seeking behavior of mosquitoes was examined by comparing attraction responses of newly colonized Aedes aegypti (L.) from field-collected eggs in Puerto Rico to that of the Gainesville (Florida) strain, originally from Orlando (Florida) and in colony since 1952. Fe...

  14. Wingbeat frequency-sweep and visual stimuli for trapping male Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Combinations of female wingbeat acoustic cues and visual cues were evaluated to determine their potential for use in male Aedes aegypti (L.) traps in peridomestic environments. A modified Centers for Disease control (CDC) light trap using a 350-500 Hz frequency-sweep broadcast from a speaker as an a...

  15. Ovicidal activity of Ageratina adenophora (Family: Asteraceae) against dengue vector, Aedes aegypti (Diptera: Culicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To determine the ovicidal efficacy of different solvent leaf extracts of Ageratina adenophora against dengue vector Aedes aegypti . Methods: The ovicidal efficacy of the crude leaf extracts of A. adenophora with five different solvents (hexane, benzene, chloroform, ethyl acetate, methanol) and was ...

  16. Different Repellents for Aedes aegypti against Blood-Feeding and Oviposition

    PubMed Central

    Afify, Ali; Horlacher, Bérénice; Roller, Johannes; Galizia, C. Giovanni

    2014-01-01

    Methyl N,N-dimethyl anthranilate (MDA), ethyl anthranilate (EA) and butyl anthranilate (BA) were previously shown to repel Aedes aegypti mosquitoes from landing on human skin. However, the effect of these compounds on the orientation of flying mosquitoes in a choice situation and their effect on mosquito oviposition are not yet known. Here, we used a modified Y-tube olfactometer to test the effect of these compounds on the orientation of Aedes aegypti flying towards skin odor (human fingers), and we tested their effect on Aedes aegypti oviposition choice in a cage assay. In both behavioral situations we compared the effect to the well-documented repellent N,N-diethyl-meta-toluamide (DEET). MDA, EA, and DEET inhibited Aedes aegypti from flying towards skin odor while BA had no such effect. Conversely, MDA had no effect on oviposition while EA, BA, and DEET deterred oviposition, with the strongest effect observed for BA. Thus, we confirm that EA and DEET are generally repellent, while MDA is repellent only in a host-seeking context, and BA is deterrent only in an oviposition context. These compounds appear of potential use in mosquito control programs. PMID:25079819

  17. Ovicidal activity of Metarhizium brunneum (Mb F52) on dengue fever vector, Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ovicidal activity of Metarhizium brunneum F52 (Mb F52) grown from granules was evaluated against Aedes aegypti eggs over time. Survival of larvae from treated eggs was significantly less when compared with untreated eggs at 7, 10 and 14 days post treatment. Only 27 % of treated eggs produced vi...

  18. Aerial ULV application of Dibrom against Aedes aegypti in simulated urban and rural residences

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reaching endophilic Aedes aegypti mosquito vectors of dengue located in human residences with aerial ULV pesticide applications is a prominent complication in operational wide area public health mosquito control activities. We conducted separate trials with a military C-130 fixed wing aircraft fitte...

  19. The maxillary palp of aedes aegypti, a model of multisensory integration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Female yellow-fever mosquitoes, Aedes aegypti, are obligate blood-feeders and vectors of the pathogens that cause dengue fever, yellow fever and Chikungunya. This feeding behavior concludes a series of multisensory events guiding the mosquito to its host from a distance. The antennae and maxillary...

  20. Toxicity of Acalypha indica (Euphorbiaceae) and Achyranthes aspera (Amaranthaceae) leaf extracts to Aedes aegypti (Diptera: Culicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternative control technologies envisioned for the dengue vector Aedes aegypti L. (Diptera: Culicidae) include botanical insecticides, which are believed to pose little threat to the environment or to human health and may provide a practical substitute for synthetic insecticides. In this study, we...

  1. Gustatory receptor expression in the labella and legs of aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The yellow-fever mosquito, Aedes aegypti, is a dangerous disease vector, infecting a growing number of people every year with dengue, yellow fever and chikungunya viruses. Contact chemoreception in mosquitoes influences a number of behaviors including host-selection, oviposition and feeding. While...

  2. Chikungunya Virus in Febrile Humans and Aedes aegypti Mosquitoes, Yucatan, Mexico

    PubMed Central

    Cigarroa-Toledo, Nohemi; Blitvich, Bradley J.; Cetina-Trejo, Rosa C.; Talavera-Aguilar, Lourdes G.; Baak-Baak, Carlos M.; Torres-Chablé, Oswaldo M.; Hamid, Md-Nafiz; Friedberg, Iddo; González-Martinez, Pedro; Alonzo-Salomon, Gabriela; Rosado-Paredes, Elsy P.; Rivero-Cárdenas, Nubia; Reyes-Solis, Guadalupe C.; Farfan-Ale, Jose A.; Garcia-Rejon, Julian E.

    2016-01-01

    Chikungunya virus (CHIKV) was isolated from 12 febrile humans in Yucatan, Mexico, in 2015. One patient was co-infected with dengue virus type 1. Two additional CHIKV isolates were obtained from Aedes aegypti mosquitoes collected in the homes of patients. Phylogenetic analysis showed that the CHIKV isolates belong to the Asian lineage. PMID:27347760

  3. Vertical Transmission of Zika Virus by Aedes aegypti and Ae. albopictus Mosquitoes.

    PubMed

    Ciota, Alexander T; Bialosuknia, Sean M; Ehrbar, Dylan J; Kramer, Laura D

    2017-05-15

    To determine the potential role of vertical transmission in Zika virus expansion, we evaluated larval pools of perorally infected Aedes. aegypti and Ae. albopictus adult female mosquitoes; ≈1/84 larvae tested were Zika virus-positive; and rates varied among mosquito populations. Thus, vertical transmission may play a role in Zika virus spread and maintenance.

  4. Household Dengue Prevention Interventions, Expenditures, and Barriers to Aedes aegypti Control in Machala, Ecuador.

    PubMed

    Heydari, Naveed; Larsen, David A; Neira, Marco; Beltrán Ayala, Efraín; Fernandez, Prissila; Adrian, Jefferson; Rochford, Rosemary; Stewart-Ibarra, Anna M

    2017-02-16

    The Aedes aegypti mosquito is an efficient vector for the transmission of Zika, chikungunya, and dengue viruses, causing major epidemics and a significant social and economic burden throughout the tropics and subtropics. The primary means of preventing these diseases is household-level mosquito control. However, relatively little is known about the economic burden of Ae. aegypti control in resource-limited communities. We surveyed residents from 40 households in a high-risk community at the urban periphery in the city of Machala, Ecuador, on dengue perceptions, vector control interventions, household expenditures, and factors influencing purchasing decisions. The results of this study show that households spend a monthly median of US$2.00, or 1.90% (range: 0.00%, 9.21%) of their family income on Ae. aegypti control interventions. Households reported employing, on average, five different mosquito control and dengue prevention interventions, including aerosols, liquid sprays, repellents, mosquito coils, and unimpregnated bed nets. We found that effectiveness and cost were the most important factors that influence people's decisions to purchase a mosquito control product. Our findings will inform the development and deployment of new Ae. aegypti control interventions by the public health and private sectors, and add to prior studies that have focused on the economic burden of dengue-like illness.

  5. Insecticidal and Repellent Activity of Several Plant-Derived Essential Oils Against Aedes aegypti.

    PubMed

    Castillo, Ruth M; Stashenko, Elena; Duque, Jonny E

    2017-03-01

    We examined the pupicidal, adulticidal, repellent, and oviposition-deterrent activities of essential oils (EOs) from Lippia alba, L. origanoides, Eucalyptus citriodora, Cymbopogon citratus, Cymbopogon flexuosus, Citrus sinensis , Cananga odorata , Swinglea glutinosa, and Tagetes lucida plants against Aedes aegypti under laboratory conditions. Pupicidal and adulticidal activities were assessed at exploratory concentrations of 250, 310, and 390 parts per million (ppm); and 30, 300, and 1,000 ppm, respectively. The greatest pupicidal activity was exhibited at 390 ppm with a 24-h exposure by L. origanoides, and 390 ppm with a 48-h exposure by Citrus sinensis . Lippia origanoides killed all adult mosquitoes at 300 ppm after 120 min of exposure. Only L. origanoides and E. citriodora EOs, applied at 1,000 ppm to human skin, produced the greatest repellency (100%) to host-seeking Ae. aegypti after 2 min of exposure; the repellency decreased between 12% and 10% after 15 min. Complete oviposition deterrence by gravid Ae. aegypti was observed for E. citriodora EOs at 200 ppm with an oviposition activity index of -1.00. These results confirm that the EOs assessed in this study have insecticidal, repellent, and oviposition-deterrent activities against the dengue vector, Ae. aegypti.

  6. Multiple Modes of Action of the Squamocin in the Midgut Cells of Aedes aegypti Larvae

    PubMed Central

    de Paula, Sérgio Oliveira; Martins, Gustavo Ferreira; Zanuncio, José Cola

    2016-01-01

    Annonaceous acetogenins are botanical compounds with good potential for use as insecticides. In the vector, Aedes aegypti (L.) (Diptera: Culicidae), squamocin (acetogenin) has been reported to be a larvicide and cytotoxic, but the modes of action of this molecule are still poorly understood. This study evaluated the changes in the cell morphology, and in the expression of genes, for autophagy (Atg1 and Atg8), for membrane ion transporter V-ATPase, and for water channel aquaporin-4 (Aqp4) in the midgut of A. aegypti larvae exposed to squamocin from Annona mucosa Jacq. (Annonaceae). Squamocin showed cytotoxic action with changes in the midgut epithelium and digestive cells of A. aegypti larvae, increase in the expression for autophagy gene Atg1 and Atg8, decrease in the expression of V-ATPase, decrease in the expression of Aqp4 gene in LC20 and inhibition of Apq4 genes in the midgut of this vector in LC50. These multiple modes of action for squamocin are described for the first time in insects, and they are important because different sites of action of squamocin from A. mucosa may reduce the possibility of resistance of A. aegypti to this molecule. PMID:27532504

  7. On the analysis of parasite effect for Aedes aegypti and Aedes albopictus population

    NASA Astrophysics Data System (ADS)

    Kallista, Meta; Aldila, Dipo; Nuraini, Nuning; Soewono, Edy

    2014-03-01

    It has been reported in some countries that the population of Aedes aegypti has been significantly reduced by the invasion of Aedes albopictus. There has been a hypothesis explaining this phenomenon of which investigated the influence of parasites pathogenesis to the competition between these two mosquito species in the fields. Ascogregarina taiwanensis and Ascogregarina culicis are known as parasites that infect Aedes albopictus and Aedes aegypti, respectively. Several studies have concluded that Ascogregarina taiwanensis caused high fatality for Aedes aegypti larvae, but Ascogregarina culicis was not pathogenic to Aedes albopictus larvae. Therefore, Ascogregarina taiwanensis may contribute to reduce the number of populations Aedes aegypti in the fields. Inspired by these facts, a mathematical model depicting interaction between parasites and mosquitoes is constructed in this paper. In this model are included six dynamic mosquito compartments, i.e. egg, larvae, infected larvae, adult, infected adult and one dynamic compartment for parasite. Derivation of the existence criteria and the stability analysis of parasite-free equilibrium as well as the basic offspring for the model are presented. Numerical simulations for sensitivity analysis indicating the invasive species for variation parameters are shown.

  8. Toxicity and Larvicidal Activity of Podophyllum-Based Lignans Against Aedes aegypti (Diptera: Culicidae).

    PubMed

    Maleck, Marise; Hollanda, Priscila de Oliveira; Serdeiro, Michele Teixeira; Soares, Renata Oliveira de Araújo; Honório, Nildimar Alves; Silva, Cláudia Gontijo

    2017-01-01

    Aedes aegypti L. (Diptera: Culicidae) is a mosquito species that has adapted to urban environments and is the main vector of dengue viruses. Because of the increasing incidence of dengue, a more environmentally acceptable insecticide needs to be found. Natural products have been and continue to be an important source of leading compounds that can be modified in order to develop new drugs. The lignan family of natural products includes compounds with a diverse spectrum of biological activity. Podophyllotoxin and its related lignans represent an exciting class of natural products that can be targeted at different types of biological activity and are therefore worth exploring further. This study had the aim of evaluating the larvicidal activity of an ethanolic extract from the rhizomes and roots of Podophyllum hexandrum (PM-3) and its isolated lignans, podophyllotoxone (1) and desoxypodophyllotoxin (2), on the larvae of the mosquito vector Ae. aegypti. The PM-3 extract and the compounds (1) and (2) were dissolved in a mixture of acetone and dimethylsulfoxide at final concentrations of 1, 10, 30, 50, 100, and 200 μg/ml. After dilution, the solutions were applied (μg/ml) to the larvae-rearing medium. Overall, the ethanolic extract from the rhizomes and roots of P. hexandrum and the compounds (1) and (2) showed larvicidal activity against the larvae of Ae. aegypti According to the results from this study, it can be concluded that podophyllotoxone (1) and desoxypodophyllotoxin (2) exhibited significant toxicity toward Ae. aegypti larvae.

  9. Vector Competence of French Polynesian Aedes aegypti and Aedes polynesiensis for Zika Virus

    PubMed Central

    Richard, Vaea; Paoaafaite, Tuterarii; Cao-Lormeau, Van-Mai

    2016-01-01

    Background In 2013–2014, French Polynesia experienced for the first time a Zika outbreak. Two Aedes mosquitoes may have contributed to Zika virus (ZIKV) transmission in French Polynesia: the worldwide distributed Ae. aegypti and the Polynesian islands-endemic Ae. polynesiensis mosquito. Methodology/Principal Findings To evaluate their vector competence for ZIKV, mosquitoes were infected per os at viral titers of 7 logs tissue culture infectious dose 50%. At several days post-infection (dpi), saliva was collected from each mosquito and inoculated onto C6/36 mosquito cells to check for the presence of ZIKV infectious particles. Legs and body of each mosquito were also collected and submitted separately to RNA extraction and ZIKV RT-PCR. In Ae. aegypti the infection rate was high as early as 6 dpi and the dissemination efficiency get substantial from 9 dpi while the both rates remained quite low in Ae. polynesiensis. The transmission efficiency was poor in Ae. aegypti until 14 dpi and no infectious saliva was found in Ae. polynesiensis at the time points studied. Conclusions/Significance In our experimental conditions, the late ability of the French Polynesian Ae. aegypti to transmit ZIKV added by the poor competence of Ae. polynesiensis for this virus suggest the possible contribution of another vector for the propagation of ZIKV during the outbreak, in particular in remote islands where Ae. polynesiensis is predominating. PMID:27654962

  10. Characterization of an Enantioselective Odorant Receptor in the Yellow Fever Mosquito Aedes aegypti

    DTIC Science & Technology

    2009-09-15

    Doolittle RE, Ladd TL, Proveaux AT (1977) Identification of the female Japanese beetle sex pheromone: Inhibition of male response by an enantiomer. Science...Characterization of an Enantioselective Odorant Receptor in the Yellow Fever Mosquito Aedes aegypti Jonathan D. Bohbot, Joseph C. Dickens* United...be differentially active at the physiological and behavioral levels. Only recently were enantioselective odorant receptors demonstrated in mammals

  11. Behavioral Response of Aedes aegypti Mosquito towards Essential Oils Using Olfactometer

    PubMed Central

    Uniyal, Ashish; Tikar, Sachin N; Mendki, Murlidhar J; Singh, Ram; Shukla, Shakti V; Agrawal, Om P; Veer, Vijay; Sukumaran, Devanathan

    2016-01-01

    Background: Aedes aegypti mosquito is responsible for transmitting human diseases like dengue and chikungunya. Personal or space protection with insect repellents is a practical approach to reducing human mosquito contact, thereby minimizing disease transmission. Essential oils are natural volatile substances from plants used as protective measure against blood-sucking mosquitoes. Methods: Twenty-three essential oils were evaluated for their repellent effect against Ae. aegypti female mosquito in laboratory conditions using Y-tube olfactometer. Results: The essential oils exhibited varying degree of repellency. Litsea oil showed 50.31%, 60.2 %, and 77.26% effective mean repellency at 1 ppm, 10 ppm and 100 ppm respectively, while DEET exhibited 59.63%, 68.63%, 85.48% and DEPA showed 57.97%, 65.43%, and 80.62% repellency at respective above concentrations. Statistical analysis revealed that among the tested essential oils, litsea oil had effective repellency in comparison with DEET and DEPA against Ae. aegypti mosquito at all concentration. Essential oils, DEET and DEPA showed significant repellence against Ae. aegypti (P< 0.05) at all 3 concentration tested. Conclusion: Litsea oil exhibited effective percentage repellency similar to DEET and DEPA. The essential oils are natural plant products that may be useful for developing safer and newer herbal based effective mosquito repellents. PMID:27308295

  12. Permethrin Induces Overexpression of Cytochrome c Oxidase Subunit 3 in Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using quantitative PCR (QPCR), the relative transcriptional levels of cytochrome c oxidase subunit 3 (CO3) were studied in Aedes aegypti (L.) in response to treatments with acetone, permethrin, or fipronil. The transcriptional levels of CO3 were significantly (p <0.05) higher in acetone-treated Ae. ...

  13. Infection with dengue-2 virus alters proteins in naturally expectorated saliva of Aedes aegypti mosquitoes

    PubMed Central

    2014-01-01

    Background Dengue virus (DENV) is responsible for up to approximately 300 million infections and an increasing number of deaths related to severe manifestations each year in affected countries throughout the tropics. It is critical to understand the drivers of this emergence, including the role of vector-virus interactions. When a DENV-infected Aedes aegypti mosquito bites a vertebrate, the virus is deposited along with a complex mixture of salivary proteins. However, the influence of a DENV infection upon the expectorated salivary proteome of its vector has yet to be determined. Methods Therefore, we conducted a proteomic analysis using 2-D gel electrophoresis coupled with mass spectrometry based protein identification comparing the naturally expectorated saliva of Aedes aegypti infected with DENV-2 relative to that of uninfected Aedes aegypti. Results Several proteins were found to be differentially expressed in the saliva of DENV-2 infected mosquitoes, in particular proteins with anti-hemostatic and pain inhibitory functions were significantly reduced. Hypothetical consequences of these particular protein reductions include increased biting rates and transmission success, and lead to alteration of transmission potential as calculated in our vectorial capacity model. Conclusions We present our characterizations of these changes with regards to viral transmission and mosquito blood-feeding success. Further, we conclude that our proteomic analysis of Aedes aegypti saliva altered by DENV infection provides a unique opportunity to identify pro-viral impacts key to virus transmission. PMID:24886023

  14. Mass trapping with MosquiTRAPs does not reduce Aedes aegypti abundance

    PubMed Central

    Degener, Carolin Marlen; de Ázara, Tatiana Mingote Ferreira; Roque, Rosemary Aparecida; Rösner, Susanne; Rocha, Eliseu Soares Oliveira; Kroon, Erna Geessien; Codeço, Cláudia Torres; Nobre, Aline Araújo; Ohly, Jörg Johannes; Geier, Martin; Eiras, Álvaro Eduardo

    2015-01-01

    The objective of this study was to evaluate the effectiveness of Aedes aegypti mass trapping using the sticky trap MosquiTRAP (MQT) by performing a cluster randomised controlled trial in Manaus, state of Amazonas, Brazil. After an initial questionnaire and baseline monitoring of adult Ae. aegypti abundance with BG-Sentinel (BGS) traps in six clusters, three clusters were randomly assigned to the intervention arm where each participating household received three MQTs for mass trapping during 17 months. The remaining three clusters (control arm) did not receive traps. The effect of mass trapping on adult Ae. aegypti abundance was monitored fortnightly with BGS traps. During the last two months of the study, a serological survey was conducted. After the study, a second questionnaire was applied in the intervention arm. Entomological monitoring indicated that MQT mass trapping did not reduce adult Ae. aegypti abundance. The serological survey indicated that recent dengue infections were equally frequent in the intervention and the control arm. Most participants responded positively to questions concerning user satisfaction. According to the results, there is no evidence that mass trapping with MQTs can be used as a part of dengue control programs. The use of this sticky trap is only recommendable for dengue vector monitoring. PMID:25946154

  15. Developmental and Environmental Regulation of AaeIAP1 Transcript in Aedes aegypti

    DTIC Science & Technology

    2008-01-01

    swine fever virus IAP ho- molog is a late structural polypeptide. Virology 214: 670Ð 674. Christophers, S. R. 1960. Aedes aegypti (L.) the yellow fever...Aedes triseriatusmosquitoes. Insect Mol. Biol. 11: 431Ð442. Chacon,M. R., F. Almazan,M. L. Nogal, E. Vinuela, and J. F. Rodriguez. 1995. The African

  16. VERTICAL TRANSMISSION OF DENGUE VIRUS IN Aedes aegypti COLLECTED IN PUERTO IGUAZÚ, MISIONES, ARGENTINA

    PubMed Central

    Espinosa, Manuel; Giamperetti, Sergio; Abril, Marcelo; Seijo, Alfredo

    2014-01-01

    A finding of vertical transmission of the DEN 3 virus in male specimens of Aedes aegypti, collected in the 2009 fall-winter period, in Puerto Iguazú city, Misiones, Argentina, using the RT-PCR technique in a 15-specimen pool is reported. This result is analyzed within the context of the epidemiological situation of Argentina's northeast border. PMID:24626420

  17. Novel estimates of Aedes aegypti (Diptera: Culicidae) population size and adult survival based on Wolbachia releases.

    PubMed

    Ritchie, Scott A; Montgomery, Brian L; Hoffmann, Ary A

    2013-05-01

    The size of Aedes aegypti (L.) mosquito populations and adult survival rates have proven difficult to estimate because of a lack of consistent quantitative measures to equate sampling methods, such as adult trapping, to actual population size. However, such estimates are critical for devising control methods and for modeling the transmission of dengue and other infectious agents carried by this species. Here we take advantage of recent releases of Wolbachia-infected Ae. aegypti coupled with the results of ongoing monitoring to estimate the size of adult Ae. aegypti populations around Cairns in far north Queensland, Australia. Based on the association between released adults infected with Wolbachia and data from Biogents Sentinel traps, we show that data from two locations are consistent with population estimates of approximately 5-10 females per house and daily survival rates of 0.7-0.9 for the released Wolbachia-infected females. Moreover, we estimate that networks of Biogents Sentinel traps at a density of one per 15 houses capture around 5-10% of the adult population per week, and provide a rapid estimate of the absolute population size of Ae. aegypti. These data are discussed with respect to release rates and monitoring in future Wolbachia releases and also the levels of suppression required to reduce dengue transmission.

  18. Microsatellite-based parentage analysis of Aedes aegypti (Diptera: Culicidae) using nonlethal DNA sampling.

    PubMed

    Wong, Jacklyn; Chu, Yui Yin; Stoddard, Steven T; Lee, Yoosook; Morrison, Amy C; Scott, Thomas W

    2012-01-01

    To track Aedes aegypti (L.) egg-laying behavior in the field in Iquitos, Peru, we developed methods for 1) sampling DNA from live mosquitoes and 2) high through-put parentage analysis using microsatellite markers. We were able to amplify DNA extracted from a single hind leg, but not from the pupal exuvia. Removal of a leg from teneral females caused no significant changes in female behavioral or life history traits (e.g., longevity, blood feeding frequency, fecundity, egg hatch rate, gonotrophic cycle length, or oviposition behavior). Using a panel of nine microsatellite markers and an exclusion-based software program, we matched offspring to parental pairs in 10 Ae. aegypti test families in which parents originated from natural development sites in Iquitos. By mating known individuals in the laboratory, retaining the male, sampling the female's DNA before release, and collecting offspring in the field, the technique we developed can be used to genotype large numbers of Ae. aegypti, reconstruct family relationships, and track the egg-laying behavior of individual Ae. aegypti in nature.

  19. Mosquito activity of a series of chalcones and 2-pyrazoline derivatives against Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aedes aegypti (L.) (Diptera: Culicidae) transmit pathogens to humans, leading to diseases such as yellow fever and dengue fever. Repellents and insecticides are two common interventions to reduce mosquito biting and thereby disease risk. However, overreliance on a chemical or class of chemicals c...

  20. Synthesis and larvicidal and adult topical activity of some hydrazide-hydrazone derivatives against Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of novel hydrazide-hydrazone derivatives were synthesized and evaluated for their larvicidal and adult topical activity against Aedes aegypti. The proposed structures of all the synthesized compounds were confirmed using elemental analysis, UV, IR, 1H-NMR, 13C-NMR and mass spectroscopy. Com...

  1. Attracted to the enemy: Aedes aegypti prefers oviposition sites with predator-killed conspecifics

    PubMed Central

    Albeny-Simoes, Daniel; Murrell, Ebony G.; Elliot, Simon L.; Andrade, Mateus R.; Lima, Eraldo; Juliano, Steven A.; Vilela, Evaldo F.

    2014-01-01

    Oviposition habitat choices of species with aquatic larvae is expected to be influenced by both offspring risk of mortality due to predation, and offspring growth potential. Aquatic predators may indirectly influence growth potential for prey by reducing prey density and, for filter feeding prey, by increasing bacterial food for prey via added organic matter (feces, partially eaten victims), creating the potential for interactive effects on oviposition choices. We tested the hypothesis that the mosquito Aedes aegypti preferentially oviposit in habitats with predatory Toxorhynchites larvae because of indirect effects of predation on chemical cues indicating bacterial abundance. We predicted that A. aegypti would avoid oviposition in sites with Toxorhynchites, but prefer to oviposit where bacterial food for larvae is abundant, and that predation by Toxorhynchites would increase bacterial abundances. Gravid A. aegypti were offered paired oviposition sites representing choices among: predator presence; the act of predation; conspecific density; dead conspecific larvae; and bacterial activity. Aedes aegypti preferentially oviposited in sites with T. theobaldi predation, and with killed conspecific larvae, but failed to detect preferences for other treatments. The antibiotic Tetracycline eliminated the strongest oviposition preference. Both predation by Toxorhynchites and killed larvae increased bacterial abundances, suggesting that oviposition attraction is cued by bacteria. Our results show the potential for indirect effects, like trophic cascades, to influence oviposition choices and community composition in aquatic systems. Our results suggest that predators like Toxorhynchites may be doubly beneficial as biocontrol agents because of the attraction of ovipositing mosquitoes to bacterial by-products of Toxorhynchites feeding. PMID:24590205

  2. Vertical transmission of dengue virus in Aedes aegypti collected in Puerto Iguazú, Misiones, Argentina.

    PubMed

    Espinosa, Manuel; Giamperetti, Sergio; Abril, Marcelo; Seijo, Alfredo

    2014-01-01

    A finding of vertical transmission of the DEN 3 virus in male specimens of Aedes aegypti, collected in the 2009 fall-winter period, in Puerto Iguazú city, Misiones, Argentina, using the RT-PCR technique in a 15-specimen pool is reported. This result is analyzed within the context of the epidemiological situation of Argentina's northeast border.

  3. Aedes aegypti (Diptera: culicidae) biting deterrence: structure-activity relationship of saturated and unsaturated fatty acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study we systematically evaluated for the first time the biting deterrent effects of a series of saturated and unsaturated fatty acids against Aedes aegypti [yellow fever mosquito (Diptera: Culicidae)] using the K & D bioassay system (Klun et al 2005). The saturated fatty acids (C6:0 to C16...

  4. Structure-Activity Relationships of 33 Carboxamides as Toxicants Against Female Aedes aegypti (Diptera: Culicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aedes aegypti (L.) is the primary vector of both dengue and yellow fever. Use of insecticides is one of the primary ways to control this medically important insect pest. However, few new insecticides have been developed for mosquito control in recent years. As a part of our effort to search for new ...

  5. AN INSULIN-LIKE PEPTIDE REGULATES EGG MATURATION AND METABOLISM IN THE MOSQUITO AEDES AEGYPTI

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ingestion of vertebrate blood is essential for egg maturation and transmission of disease-causing parasites by female mosquitoes. Prior studies with the yellow fever mosquito, Aedes aegypti, indicated blood feeding stimulates egg production by triggering the release of hormones from MNCs in the mosq...

  6. Long-term spatio-temporal dynamics of the mosquito Aedes aegypti in temperate Argentina.

    PubMed

    Fischer, S; De Majo, M S; Quiroga, L; Paez, M; Schweigmann, N

    2017-04-01

    Buenos Aires city is located near the southern limit of the distribution of Aedes aegypti (Diptera: Culicidae). This study aimed to assess long-term variations in the abundance of Ae. aegypti in Buenos Aires in relation to changes in climatic conditions. Ae. aegypti weekly oviposition activity was analyzed and compared through nine warm seasons from 1998 to 2014, with 200 ovitraps placed across the whole extension of the city. The temporal and spatial dynamics of abundances were compared among seasons, and their relation with climatic variables were analyzed. Results showed a trend to higher peak abundances, a higher number of infested sites, and longer duration of the oviposition season through subsequent years, consistent with a long-term colonization process. In contrast, thermal favorability and rainfall pattern did not show a consistent trend of changes. The long-term increase in abundance, and the recently documented expansion of Ae. aegypti to colder areas of Buenos Aires province suggest that local populations might be adapting to lower temperature conditions. The steadily increasing abundances may have implications on the risk of dengue transmission.

  7. Promising Aedes aegypti repellent chemotypes identified through integrated QSAE, virtual screening, synthesis, and bioassay

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Molecular field topology analysis, scaffold hopping, and molecular docking were used as complementary computational tools for the design of repellents for Aedes aegypti, the insect vector for yellow fever, West Nile fever, and dengue fever. A large number of analogues were evaluated by virtual scree...

  8. Toxicity and Larvicidal Activity of Podophyllum-Based Lignans Against Aedes aegypti (Diptera: Culicidae).

    PubMed

    Maleck, Marise; Hollanda, Priscila de Oliveira; Serdeiro, Michele Teixeira; Soares, Renata Oliveira de Araújo; Honório, Nildimar Alves; Silva, Cláudia Gontijo

    2016-08-25

    Aedes aegypti L. (Diptera: Culicidae) is a mosquito species that has adapted to urban environments and is the main vector of dengue viruses. Because of the increasing incidence of dengue, a more environmentally acceptable insecticide needs to be found. Natural products have been and continue to be an important source of leading compounds that can be modified in order to develop new drugs. The lignan family of natural products includes compounds with a diverse spectrum of biological activity. Podophyllotoxin and its related lignans represent an exciting class of natural products that can be targeted at different types of biological activity and are therefore worth exploring further. This study had the aim of evaluating the larvicidal activity of an ethanolic extract from the rhizomes and roots of Podophyllum hexandrum (PM-3) and its isolated lignans, podophyllotoxone (1) and desoxypodophyllotoxin (2), on the larvae of the mosquito vector Ae. aegypti. The PM-3 extract and the compounds (1) and (2) were dissolved in a mixture of acetone and dimethylsulfoxide at final concentrations of 1, 10, 30, 50, 100, and 200 μg/ml. After dilution, the solutions were applied (μg/ml) to the larvae-rearing medium. Overall, the ethanolic extract from the rhizomes and roots of P. hexandrum and the compounds (1) and (2) showed larvicidal activity against the larvae of Ae. aegypti According to the results from this study, it can be concluded that podophyllotoxone (1) and desoxypodophyllotoxin (2) exhibited significant toxicity toward Ae. aegypti larvae.

  9. Different repellents for Aedes aegypti against blood-feeding and oviposition.

    PubMed

    Afify, Ali; Horlacher, Bérénice; Roller, Johannes; Galizia, C Giovanni

    2014-01-01

    Methyl N,N-dimethyl anthranilate (MDA), ethyl anthranilate (EA) and butyl anthranilate (BA) were previously shown to repel Aedes aegypti mosquitoes from landing on human skin. However, the effect of these compounds on the orientation of flying mosquitoes in a choice situation and their effect on mosquito oviposition are not yet known. Here, we used a modified Y-tube olfactometer to test the effect of these compounds on the orientation of Aedes aegypti flying towards skin odor (human fingers), and we tested their effect on Aedes aegypti oviposition choice in a cage assay. In both behavioral situations we compared the effect to the well-documented repellent N,N-diethyl-meta-toluamide (DEET). MDA, EA, and DEET inhibited Aedes aegypti from flying towards skin odor while BA had no such effect. Conversely, MDA had no effect on oviposition while EA, BA, and DEET deterred oviposition, with the strongest effect observed for BA. Thus, we confirm that EA and DEET are generally repellent, while MDA is repellent only in a host-seeking context, and BA is deterrent only in an oviposition context. These compounds appear of potential use in mosquito control programs.

  10. Mass trapping with MosquiTRAPs does not reduce Aedes aegypti abundance.

    PubMed

    Degener, Carolin Marlen; de Ázara, Tatiana Mingote Ferreira; Roque, Rosemary Aparecida; Rösner, Susanne; Rocha, Eliseu Soares Oliveira; Kroon, Erna Geessien; Codeço, Cláudia Torres; Nobre, Aline Araújo; Ohly, Jörg Johannes; Geier, Martin; Eiras, Álvaro Eduardo

    2015-06-01

    The objective of this study was to evaluate the effectiveness of Aedes aegypti mass trapping using the sticky trap MosquiTRAP (MQT) by performing a cluster randomised controlled trial in Manaus, state of Amazonas, Brazil. After an initial questionnaire and baseline monitoring of adult Ae. aegypti abundance with BG-Sentinel (BGS) traps in six clusters, three clusters were randomly assigned to the intervention arm where each participating household received three MQTs for mass trapping during 17 months. The remaining three clusters (control arm) did not receive traps. The effect of mass trapping on adult Ae. aegypti abundance was monitored fortnightly with BGS traps. During the last two months of the study, a serological survey was conducted. After the study, a second questionnaire was applied in the intervention arm. Entomological monitoring indicated that MQT mass trapping did not reduce adult Ae. aegypti abundance. The serological survey indicated that recent dengue infections were equally frequent in the intervention and the control arm. Most participants responded positively to questions concerning user satisfaction. According to the results, there is no evidence that mass trapping with MQTs can be used as a part of dengue control programs. The use of this sticky trap is only recommendable for dengue vector monitoring.

  11. Genetics and morphology of Aedes aegypti (Diptera: Culicidae) in septic tanks in Puerto Rico.

    PubMed

    Somers, Gerard; Brown, Julia E; Barrera, Roberto; Powell, Jeffrey R

    2011-11-01

    Dengue viruses, primarily transmitted by the mosquito Aedes aegypti (L.), affect an estimated 50-100 million people yearly. Traditional approaches to control mosquito population numbers, such as the use of pesticides, have had only limited success. Atypical mosquito behavior may be one reason why current vector control efforts have been less efficacious than expected. In Puerto Rico, for example, adult Ae. aegypti have been observed emerging from septic tanks. Interestingly, adults emerging from septic tanks are larger on average than adults collected from surface containers. To determine whether adults colonizing septic tanks constitute a separate Ae. aegypti population, we used 12 previously validated microsatellite loci to examine adult mosquitoes collected from both septic tanks and surface containers, but found no evidence to suggest genetic differentiation. Size differences between septic tank and surface mosquitoes were reduced when nutrient levels were held constant across experimental groups. Despite the absence of evidence suggesting a genetic difference between experimental groups in this study, Ae. aegypti emerging from septic tanks may still represent a more dangerous phenotype and should be given special consideration when developing vector control programs and designing public health interventions in the future.

  12. A new tent trap for monitoring the daily activity of Aedes aegypti and Aedes albopictus.

    PubMed

    Casas Martínez, Mauricio; Orozco Bonilla, Arnoldo; Muñoz Reyes, Miguel; Ulloa García, Armando; Bond, J Guillermo; Valle Mora, Javier; Weber, Manuel; Rojas, Julio C

    2013-12-01

    In this study, we designed a new tent trap; the BioDiVector (BDV) tent trap, consisting of two rectangular tents that use human bait without endangering the technical personnel. The daily activity pattern of Aedes aegypti and Aedes albopictus in intra, peri, and extradomiciliary sites was studied in an endemic area of dengue in southern Mexico by using the BDV tent trap. Totals of 3,128 individuals of Ae. aegypti and 833 Ae. albopictus were captured. More Ae. aegypti males than females were caught, while the opposite was true with Ae. albopictus. The activity of both mosquito species was affected by the interaction between the collection site and time of day. In general, more individuals of both mosquito species were captured at the extradomicillary sites than at the peri and intradomicillary sites. Mosquitoes showed two peaks of activity, one in the morning and the other in the afternoon, but in general this only occurred at the extradomicillary sites, whereas no peak of activity was observed at the intra and peridomicillary sites. Overall, Ae. aegypti had a higher indirect biting rate than Ae. albopictus. Finally, due to its efficiency, simplicity, and low cost, we suggest the use of this innovative tool for entomological surveillance, bionomics and vector incrimination studies in geographical areas where dengue and other arboviruses are present.

  13. Lethal ovitrap deployment for Aedes aegypti control: potential implications for non-target organisms.

    PubMed

    Long, Sharron A; Jacups, Susan P; Ritchie, Scott A

    2015-06-01

    In Australia, dengue control combines source reduction with lethal ovitraps to reduce Aedes aegypti populations during outbreaks. Lethal ovitraps are considered a sustainable and environmentally friendly method of controlling container-inhabiting mosquitoes, however, to-date, this claim has not been quantified. This study assesses the potential impact of lethal ovitraps on non-target organisms when used to control Ae. aegypti in tropical Australia. For retention of specimens, we substituted standard sticky ovitraps for lethal ovitraps. We collected 988 Ae. aegypti and 44,132 non-target specimens over 13 months from 16 sites. Although Ae. aegypti comprised only 2.2% of the total collection, they were were the eighth most dominant taxa collected, on the 93(rd) percentile. Of the non-target organisms, Collembola were the dominant taxa, 44.2%, with 36.8% and 10.5% Diptera and Hymenoptera, respectively. Of the Dipterans, 61% were family Phoridae. Lethal ovitraps were visited by 90 insect or invertebrate families in total. Ovitraps are attractive to Collembola, Phoridae, Sciaridae, Formicidae, and Culicidae, with minimal attraction by Apidae and other commonly monitored non-target organisms. For container-inhabiting mosquitoes, LOs are cost effective operationally, requiring minimal staff resources for placement and retrieval.

  14. Transcript profiling of the meiotic drive phenotype in testis of Aedes aegypti using suppressive subtractive hybridization.

    PubMed

    Shin, Dongyoung; Jin, Lizhong; Lobo, Neil F; Severson, David W

    2011-09-01

    The meiotic drive gene in Aedes aegypti is tightly linked with the sex determination locus on chromosome 1, and causes highly male-biased sex ratios. We prepared cDNA libraries from testes from the Ae. aegypti T37 strain (driving) and RED strain (non-driving), and used suppressive subtraction hybridization techniques to enrich for T37 testes-specific transcripts. Expressed sequence tags (ESTs) were obtained from a total of 2784 randomly selected clones from the subtracted T37 (subT37) library as well as the primary libraries for each strain (pT37 and pRED). Sequence analysis identified a total of 171 unique genes in the subT37 library and 299 unique genes among the three libraries. The majority of genes enriched in the subT37 library were associated with signal transduction, development, reproduction, metabolic process and cell cycle functions. Further, as observed with meiotic drive systems in Drosophila and mouse, a number of these genes were associated with signaling cascades that involve the Ras superfamily of regulatory small GTPases. Differential expression of several of these genes was verified in Ae. aegypti pupal testes using qRT-PCR. This study increases our understanding of testes gene expression enriched in adult males from the meiotic drive strain as well as insights into the basic testes transcriptome in Ae. aegypti.

  15. Environmental and Genetic Factors Determine Whether the Mosquito Aedes aegypti Lays Eggs without a Blood Meal

    PubMed Central

    Ariani, Cristina V.; Smith, Sophia C. L.; Osei-Poku, Jewelna; Short, Katherine; Juneja, Punita; Jiggins, Francis M.

    2015-01-01

    Some mosquito strains or species are able to lay eggs without taking a blood meal, a trait named autogeny. This may allow populations to persist through times or places where vertebrate hosts are scarce. Autogenous egg production is highly dependent on the environment in some species, but the ideal conditions for its expression in Aedes aegypti mosquitoes are unknown. We found that 3.2% of females in a population of Ae. aegypti from Kenya were autogenous. Autogeny was strongly influenced by temperature, with many more eggs laid at 28°C compared with 22°C. Good nutrition in larval stages and feeding on higher concentrations of sugar solution during the adult stage both result in more autogenous eggs being produced. The trait also has a genetic basis, as not all Ae. aegypti genotypes can lay autogenously. We conclude that Ae. aegypti requires a favorable environment and a suitable genotype to be able to lay eggs without a blood meal. PMID:25646251

  16. Household Dengue Prevention Interventions, Expenditures, and Barriers to Aedes aegypti Control in Machala, Ecuador

    PubMed Central

    Heydari, Naveed; Larsen, David A.; Neira, Marco; Beltrán Ayala, Efraín; Fernandez, Prissila; Adrian, Jefferson; Rochford, Rosemary; Stewart-Ibarra, Anna M.

    2017-01-01

    The Aedes aegypti mosquito is an efficient vector for the transmission of Zika, chikungunya, and dengue viruses, causing major epidemics and a significant social and economic burden throughout the tropics and subtropics. The primary means of preventing these diseases is household-level mosquito control. However, relatively little is known about the economic burden of Ae. aegypti control in resource-limited communities. We surveyed residents from 40 households in a high-risk community at the urban periphery in the city of Machala, Ecuador, on dengue perceptions, vector control interventions, household expenditures, and factors influencing purchasing decisions. The results of this study show that households spend a monthly median of US$2.00, or 1.90% (range: 0.00%, 9.21%) of their family income on Ae. aegypti control interventions. Households reported employing, on average, five different mosquito control and dengue prevention interventions, including aerosols, liquid sprays, repellents, mosquito coils, and unimpregnated bed nets. We found that effectiveness and cost were the most important factors that influence people’s decisions to purchase a mosquito control product. Our findings will inform the development and deployment of new Ae. aegypti control interventions by the public health and private sectors, and add to prior studies that have focused on the economic burden of dengue-like illness. PMID:28212349

  17. Toxicity of Cephalaria species and their individual constituents against Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crude acetone and ethanol extracts of the aerial parts of 21 Cephalaria species collected from Turkey were investigated for larvicidal and adult topical activity against Aedes aegypti. The ethanol extracts from C. elazigensis var. purpurea, C. anatolica, and C. elmaliensis possessed the highest mort...

  18. Exposure to chikungunya virus and adult longevity in Aedes aegypti (L.) and Aedes albopictus (Skuse).

    PubMed

    Reiskind, Michael H; Westbrook, Catherine J; Lounibos, L Philip

    2010-06-01

    Chikungunya virus (CHIKV) recently emerged as a global threat to public health through its adaptation to the cosmopolitan mosquito Aedes albopictus Skuse. Aedes albopictus is highly susceptible to the emergent strain of CHIKV, relative to the historical vector of CHIKV, Aedes aegypti (L.). We hypothesized that the high susceptibility of Ae. albopictus to CHIKV may have a cost in terms of longevity and fecundity among infected vs non-infected mosquitoes, relative to Ae. aegypti. We performed a longevity experiment comparing Ae. aegypti and Ae. albopictus exposed to the emergent strain of CHIKV (LR-2006OPY1). We found a small but significant decrease in longevity of Ae. albopictus, but not Ae. aegypti, in response to exposure to CHIKV. We did not observe significant differences in numbers of eggs laid by either species in response to exposure. Longevity and body titer of infected Ae. albopictus were significantly negatively correlated, such that individuals that lived longer had lower viral body titers when they died. The cost of exposure, while not high, suggests there may be physiological constraints in the evolution of viral infectiousness in its insect vector.

  19. Oviposition-Stimulant and Ovicidal Activities of Moringa oleifera Lectin on Aedes aegypti

    PubMed Central

    Santos, Nataly Diniz de Lima; de Moura, Kézia Santana; Napoleão, Thiago Henrique; Santos, Geanne Karla Novais; Coelho, Luana Cassandra Breitenbach Barroso; Navarro, Daniela Maria do Amaral Ferraz; Paiva, Patrícia Maria Guedes

    2012-01-01

    Background Natural insecticides against the vector mosquito Aedes aegypti have been the object of research due to their high level of eco-safety. The water-soluble Moringa oleifera lectin (WSMoL) is a larvicidal agent against A. aegypti. This work reports the effects of WSMoL on oviposition and egg hatching of A. aegypti. Methodology/Principal Findings WSMoL crude preparations (seed extract and 0–60 protein fraction), at 0.1 mg/mL protein concentration, did not affect oviposition, while A. aegypti gravid females laid their eggs preferentially (73%) in vessels containing isolated WSMoL (0.1 mg/mL), compared with vessels containing only distilled water (control). Volatile compounds were not detected in WSMoL preparation. The hatchability of fresh eggs deposited in the solutions in the oviposition assay was evaluated. The numbers of hatched larvae in seed extract, 0–60 protein fraction and WSMoL were 45±8.7 %, 20±11 % and 55±7.5 %, respectively, significantly (p<0.05) lower than in controls containing only distilled water (75–95%). Embryos were visualized inside fresh control eggs, but not within eggs that were laid and maintained in WSMoL solution. Ovicidal activity was also assessed using stored A. aegypti eggs. The protein concentrations able to reduce the hatching rate by 50% (EC50) were 0.32, 0.16 and 0.1 mg/mL for seed extract, 0–60 protein fraction and WSMoL, respectively. The absence of hatching of stored eggs treated with WSMoL at 0.3 mg/mL (EC99) after transfer to medium without lectin indicates that embryos within the eggs were killed by WSMoL. The reduction in hatching rate of A. aegypti was not linked to decrease in bacteria population. Conclusions/Significance WSMoL acted both as a chemical stimulant cue for ovipositing females and ovicidal agent at a given concentration. The oviposition-stimulant and ovicidal activities, combined with the previously reported larvicidal activity, make WSMoL a very interesting candidate in integrated A. aegypti

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

    PubMed

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

    2014-01-01

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

  1. Aedes aegypti Global Suitability Maps Using a Water Container Energy Balance Model for Dengue Risk Applications

    NASA Astrophysics Data System (ADS)

    Steinhoff, D.

    2015-12-01

    Dengue infections are estimated to total nearly 400 million per year worldwide, with both the geographic range and the magnitude of infections having increased in the past 50 years. The primary dengue vector mosquito Aedes aegypti is closely associated with humans. It lives exclusively in urban and semi-urban areas, preferentially bites humans, and spends its developmental stages in artificial water containers. Climate regulates the development of Ae. aegypti immature mosquitoes in artificial containers. Potential containers for Ae. aegypti immature development include, but are not limited to, small sundry items (e.g., bottles, cans, plastic containers), buckets, tires, barrels, tanks, and cisterns. Successful development of immature mosquitoes from eggs to larvae, pupae, and eventually adults is largely dependent on the availability of water and the thermal properties of the water in the containers. Recent work has shown that physics-based approaches toward modeling container water properties are promising for resolving the complexities of container water dynamics and the effects on immature mosquito development. An energy balance container model developed by the author, termed the Water Height And Temperature in Container Habitats Energy Model (WHATCH'EM), solves for water temperature and height for user-specified containers with readily available weather data. Here we use WHATCH'EM with NASA Earth Science products used as input to construct global suitability maps based on established water temperature ranges for immature Ae. aegypti mosquitoes. A proxy for dengue risk is provided from habitat suitability, but also population estimates, as Ae. aegypti is closely associated with human activity. NASA gridded Global Population of the World data is used to mask out rural areas with low dengue risk. Suitability maps are illustrated for a variety of containers (size, material, color) and shading scenarios.

  2. The wMel Strain of Wolbachia Reduces Transmission of Chikungunya Virus in Aedes aegypti

    PubMed Central

    Aliota, Matthew T.; Walker, Emma C.; Uribe Yepes, Alexander; Dario Velez, Ivan; Christensen, Bruce M.; Osorio, Jorge E.

    2016-01-01

    Background New approaches to preventing chikungunya virus (CHIKV) are needed because current methods are limited to controlling mosquito populations, and they have not prevented the invasion of this virus into new locales, nor have they been sufficient to control the virus upon arrival. A promising candidate for arbovirus control and prevention relies on the introduction of the intracellular bacterium Wolbachia into Aedes aegypti mosquitoes. This primarily has been proposed as a tool to control dengue virus (DENV) transmission; however, evidence suggests Wolbachia infections confer protection for Ae. aegypti against CHIKV. Although this approach holds much promise for limiting virus transmission, at present our understanding of the ability of CHIKV to infect, disseminate, and be transmitted by wMel-infected Ae. aegypti currently being used at Wolbachia release sites is limited. Methodology/Principal Findings Using Ae. aegypti infected with the wMel strain of Wolbachia that are being released in Medellin, Colombia, we report that these mosquitoes have reduced vector competence for CHIKV, even with extremely high viral titers in the bloodmeal. In addition, we examined the dynamics of CHIKV infection over the course of four to seven days post feeding. Wolbachia-infected mosquitoes remained non-infective over the duration of seven days, i.e., no infectious virus was detected in the saliva when exposed to bloodmeals of moderate viremia, but CHIKV-exposed, wild type mosquitoes did have viral loads in the saliva consistent with what has been reported elsewhere. Finally, the presence of wMel infection had no impact on the lifespan of mosquitoes as compared to wild type mosquitoes following CHIKV infection. Conclusions/Significance These results could have an impact on vector control strategies in areas where Ae. aegypti are transmitting both DENV and CHIKV; i.e., they argue for further exploration, both in the laboratory and the field, on the feasibility of expanding this

  3. Screening of Methanolic Plant Extracts against Larvae of Aedes aegypti and Anopheles stephensi in Mysore

    PubMed Central

    Mohankumar, Thirumalapura Krishnaiah; Shivanna, Kumuda Sathigal; Achuttan, Vijayan Valiakottukal

    2016-01-01

    Background: Mosquitoes transmit serious human diseases, causing millions of death every year. Vector control is facing a threat due to the emergence of resistance to synthetic insecticides. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. Nine different locally available medicinally important plants suspected to posse larvicidal property were screened against fourth instar larvae of Aedes aegypti and Anopheles stephensi to a series of concentrations of the methanolic extracts. Methods: Susceptibility tests on Ae. aegypti and An. stephensi were conducted using standard WHO methods. The larvae of two mosquito species were exposed to methanolic extracts and mortality counts were made after 24 hours of exposure as per WHO method. Larvae of Ae. aegypti were more susceptible than that of An. stephensi. Results: Among the nine plant species tested, Annona reticulata leaf extract was more effective against Ae. aegypti larvae with LC50 and LC90 values of 95.24 and 262.64 ppm respectively and against An. stephensi larvae 262.71 and 636.94 ppm respectively. The least efficacy was in Cosmos bipinnatus with LC50 and LC90 values of 442.6 and 1225.93 ppm against Ae. aegypti and LC50 and LC90 values of 840.69 and 1334.01 ppm of Thespesia populnea against An. stephensi. Conclusion: The crude methanolic extract of the An. reticulata with good larvicidal efficacy could be considered for further characterization to control mosquito vectors instead of chemical insecticides. High efficacy found in An. reticulata extract will be considered for further studies to isolate the bioactive compound. PMID:27308289

  4. Differential Susceptibilities of Aedes aegypti and Aedes albopictus from the Americas to Zika Virus

    PubMed Central

    Vazeille, Marie; Yebakima, André; Girod, Romain; Goindin, Daniella; Dupont-Rouzeyrol, Myrielle; Lourenço-de-Oliveira, Ricardo; Failloux, Anna-Bella

    2016-01-01

    Background Since the major outbreak in 2007 in the Yap Island, Zika virus (ZIKV) causing dengue-like syndromes has affected multiple islands of the South Pacific region. In May 2015, the virus was detected in Brazil and then spread through South and Central America. In December 2015, ZIKV was detected in French Guiana and Martinique. The aim of the study was to evaluate the vector competence of the mosquito spp. Aedes aegypti and Aedes albopictus from the Caribbean (Martinique, Guadeloupe), North America (southern United States), South America (Brazil, French Guiana) for the currently circulating Asian genotype of ZIKV isolated from a patient in April 2014 in New Caledonia. Methodology/Principal Findings Mosquitoes were orally exposed to an Asian genotype of ZIKV (NC-2014-5132). Upon exposure, engorged mosquitoes were maintained at 28°±1°C, a 16h:8h light:dark cycle and 80% humidity. 25–30 mosquitoes were processed at 4, 7 and 14 days post-infection (dpi). Mosquito bodies (thorax and abdomen), heads and saliva were analyzed to measure infection, dissemination and transmission, respectively. High infection but lower disseminated infection and transmission rates were observed for both Ae. aegypti and Ae. albopictus. Ae. aegypti populations from Guadeloupe and French Guiana exhibited a higher dissemination of ZIKV than the other Ae. aegypti populations examined. Transmission of ZIKV was observed in both mosquito species at 14 dpi but at a low level. Conclusions/Significance This study suggests that although susceptible to infection, Ae. aegypti and Ae. albopictus were unexpectedly low competent vectors for ZIKV. This may suggest that other factors such as the large naïve population for ZIKV and the high densities of human-biting mosquitoes contribute to the rapid spread of ZIKV during the current outbreak. PMID:26938868

  5. Impact of Terminalia chebula Retz. against Aedes aegypti L. and non-target aquatic predatory insects.

    PubMed

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

    2017-03-01

    Aedes aegypti Linn is one of the most important mosquito species. The vectors are responsible for causing deadly diseases like dengue and dengue hemorrhagic fever. Several chemical pesticides used to control these dengue vectors caused severe toxic significances on human health and other non-target beneficial insects. Therefore the current investigation has been made to access the bio-efficacy of the crude seed extracts of T. chebula against the dengue vector Ae. aegypti. The GC-MS analysis of crude seed extracts of T. chebula identified nine chemical compounds with major peak area in the 1,2,3-Benzenetriol (61.96%), followed by Tridecanoic acid (09.55%). Ae. aegypti larvae showed dose dependent mortality rate was observed between the treatments. Prominent protection rate at greater concentrations of 100ppm and moderate protection at 75 and 50ppm was observed in the repellent assay. Lethal concentration (LC50 and LC90) of fourth instar larvae of Ae. aegypti was observed in 138 and 220ppm concentration respectively. Similarly, the seed extracts showed 100% adulticidal activity at the concentration of 400ppm at 30min of exposure time. Phytochemicals present in the seed extracts of T. chebula significantly affects the major portions of the midgut tissues of Ae. aegypti at the concentration of 100ppm. The toxicological evaluation of seed extracts also proved non-toxic towards the A. bouvieri and Tx. splendens aquatic predatory insects. Hence, the present result suggest that bio-rational plant derived T. chebula could be incorporated in the dengue vector control and have no adverse effects on non-target beneficial insects.

  6. Evaluation of the present dengue situation and control strategies against Aedes aegypti in Cebu City, Philippines.

    PubMed

    Mahilum, Milagros M; Ludwig, Mario; Madon, Minoo B; Becker, Norbert

    2005-12-01

    The present dengue situation and methods to control Aedes aegypti larvae in Cebu City, Philippines, were evaluated for the development of an integrated community-based dengue control program. The study included the detection of dengue infection among Filipino patients, surveying mosquito breeding sites to determine larval population density of Aedes aegypti, an evaluation of public knowledge, attitude, and personal protection practices against dengue, and an evaluation of the efficacy of VectoBac DT/Culinex Tab tablets based on Bacillus thuringiensis israelensis against Ae. aegypti larvae. Of the 173 human sera samples that were assayed for dengue viruses, 94.9% were positive, 2.2% negative and 2.8% equivocal. Thirty households were randomly chosen per Barangay "Villages" (lowest level of formal local administration). Of the 489 breeding sites surveyed, 29.4% were infested with Ae. aegypti larvae, with discarded tires having the highest infestation rate (69.4%). A survey of people's knowledge, attitude, and practices for integrated community-based dengue control showed that 68.7% of the interviewees were aware that dengue is transmitted by mosquitoes, but only 4.3% knew that a virus was the cause of the disease. The efficacy of one and two tablets of VectoBac DT/Culinex Tab, based on Bacillus thuringiensis israelensis, was assessed against the larvae of Ae. aegypti exposed to sunshine and shaded water containers in semi-field and field tests. In semi-field tests, 100% mortality was achieved until the 18th and 30th day after the application of one and two tablets, respectively, in sun-exposed containers. In shaded containers, 100% mortality was observed until the 30th and 36th day after the application of one and two tablets, respectively. In field tests, the tablets were effective for approximately 3 weeks.

  7. The wMel Wolbachia strain blocks dengue and invades caged Aedes aegypti populations.

    PubMed

    Walker, T; Johnson, P H; Moreira, L A; Iturbe-Ormaetxe, I; Frentiu, F D; McMeniman, C J; Leong, Y S; Dong, Y; Axford, J; Kriesner, P; Lloyd, A L; Ritchie, S A; O'Neill, S L; Hoffmann, A A

    2011-08-24

    Dengue fever is the most important mosquito-borne viral disease of humans with more than 50 million cases estimated annually in more than 100 countries. Disturbingly, the geographic range of dengue is currently expanding and the severity of outbreaks is increasing. Control options for dengue are very limited and currently focus on reducing population abundance of the major mosquito vector, Aedes aegypti. These strategies are failing to reduce dengue incidence in tropical communities and there is an urgent need for effective alternatives. It has been proposed that endosymbiotic bacterial Wolbachia infections of insects might be used in novel strategies for dengue control. For example, the wMelPop-CLA Wolbachia strain reduces the lifespan of adult A. aegypti mosquitoes in stably transinfected lines. This life-shortening phenotype was predicted to reduce the potential for dengue transmission. The recent discovery that several Wolbachia infections, including wMelPop-CLA, can also directly influence the susceptibility of insects to infection with a range of insect and human pathogens has markedly changed the potential for Wolbachia infections to control human diseases. Here we describe the successful transinfection of A. aegypti with the avirulent wMel strain of Wolbachia, which induces the reproductive phenotype cytoplasmic incompatibility with minimal apparent fitness costs and high maternal transmission, providing optimal phenotypic effects for invasion. Under semi-field conditions, the wMel strain increased from an initial starting frequency of 0.65 to near fixation within a few generations, invading A. aegypti populations at an accelerated rate relative to trials with the wMelPop-CLA strain. We also show that wMel and wMelPop-CLA strains block transmission of dengue serotype 2 (DENV-2) in A. aegypti, forming the basis of a practical approach to dengue suppression.

  8. Mesocyclops longisetus effects on survivorship of Aedes aegypti immature stages in car tyres.

    PubMed

    Manrique-Saide, P; Ibáñez-Bernal, S; Delfín-González, H; Parra Tabla, V

    1998-10-01

    The effect of the introduction of the entomophagous copepod Mesocyclops longisetus (Acuacultura F.C.B. strain) on the survival of Aedes aegypti immature stages in car tyres was evaluated under semi-natural conditions in the municipality of Merida, Yucatan, Mexico. Life tables were constructed for the immature stages of the mosquito in the presence and absence of M. longisetus, and the survival data were compared using log-linear models. The data set was adjusted using the GLIM statistical package and the quality of adjustment was evaluated with a chi-squared test. Survivorship curves were constructed for each treatment. In the absence of M. longisetus, the survivorship of Ae. aegypti immature stages averaged 9%. The highest mortality rate was observed during the fourth larval instar (54%) and the resulting survival pattern corresponded to a type II survivorship curve. The mortality rate of Ae. aegypti first-instar larvae (fifty per tyre) increased more than 200-fold in the presence of M. longisetus (twenty per tyre) and the highest mortality was during the first two larval instars, where it reached 98.9%, with a resulting survivorship of 0.2%. Overall mortality was sixfold greater in the presence of the copepod than in its absence. The survival pattern of immature stages of Ae. aegypti in the presence of the copepod corresponded to a type III survivorship curve. As M. longisetus was so effective against Ae. aegypti immature stages in tyres under seminatural conditions, its long-term effectiveness should be evaluated under socially and ecologically realistic field conditions in Mexico.

  9. Evaluation of Location-Specific Predictions by a Detailed Simulation Model of Aedes aegypti Populations

    PubMed Central

    Legros, Mathieu; Magori, Krisztian; Morrison, Amy C.; Xu, Chonggang; Scott, Thomas W.; Lloyd, Alun L.; Gould, Fred

    2011-01-01

    Background Skeeter Buster is a stochastic, spatially explicit simulation model of Aedes aegypti populations, designed to predict the outcome of vector population control methods. In this study, we apply the model to two specific locations, the cities of Iquitos, Peru, and Buenos Aires, Argentina. These two sites differ in the amount of field data that is available for location-specific customization. By comparing output from Skeeter Buster to field observations in these two cases we evaluate population dynamics predictions by Skeeter Buster with varying degrees of customization. Methodology/Principal Findings Skeeter Buster was customized to the Iquitos location by simulating the layout of houses and the associated distribution of water-holding containers, based on extensive surveys of Ae. aegypti populations and larval habitats that have been conducted in Iquitos for over 10 years. The model is calibrated by adjusting the food input into various types of containers to match their observed pupal productivity in the field. We contrast the output of this customized model to the data collected from the natural population, comparing pupal numbers and spatial distribution of pupae in the population. Our results show that Skeeter Buster replicates specific population dynamics and spatial structure of Ae. aegypti in Iquitos. We then show how Skeeter Buster can be customized for Buenos Aires, where we only had Ae. aegypti abundance data that was averaged across all locations. In the Argentina case Skeeter Buster provides a satisfactory simulation of temporal population dynamics across seasons. Conclusions This model can provide a faithful description of Ae. aegypti populations, through a process of location-specific customization that is contingent on the amount of data available from field collections. We discuss limitations presented by some specific components of the model such as the description of food dynamics and challenges that these limitations bring to model

  10. Spatial Patterns of High Aedes aegypti Oviposition Activity in Northwestern Argentina

    PubMed Central

    Estallo, Elizabet Lilia; Más, Guillermo; Vergara-Cid, Carolina; Lanfri, Mario Alberto; Ludueña-Almeida, Francisco; Scavuzzo, Carlos Marcelo; Introini, María Virginia; Zaidenberg, Mario; Almirón, Walter Ricardo

    2013-01-01

    Background In Argentina, dengue has affected mainly the Northern provinces, including Salta. The objective of this study was to analyze the spatial patterns of high Aedes aegypti oviposition activity in San Ramón de la Nueva Orán, northwestern Argentina. The location of clusters as hot spot areas should help control programs to identify priority areas and allocate their resources more effectively. Methodology Oviposition activity was detected in Orán City (Salta province) using ovitraps, weekly replaced (October 2005–2007). Spatial autocorrelation was measured with Moran’s Index and depicted through cluster maps to identify hot spots. Total egg numbers were spatially interpolated and a classified map with Ae. aegypti high oviposition activity areas was performed. Potential breeding and resting (PBR) sites were geo-referenced. A logistic regression analysis of interpolated egg numbers and PBR location was performed to generate a predictive mapping of mosquito oviposition activity. Principal Findings Both cluster maps and predictive map were consistent, identifying in central and southern areas of the city high Ae. aegypti oviposition activity. A logistic regression model was successfully developed to predict Ae. aegypti oviposition activity based on distance to PBR sites, with tire dumps having the strongest association with mosquito oviposition activity. A predictive map reflecting probability of oviposition activity was produced. The predictive map delimitated an area of maximum probability of Ae. aegypti oviposition activity in the south of Orán city where tire dumps predominate. The overall fit of the model was acceptable (ROC = 0.77), obtaining 99% of sensitivity and 75.29% of specificity. Conclusions Distance to tire dumps is inversely associated with high mosquito activity, allowing us to identify hot spots. These methodologies are useful for prevention, surveillance, and control of tropical vector borne diseases and might assist National Health

  11. Excito-repellency of essential oils against an Aedes aegypti (L.) field population in Thailand.

    PubMed

    Boonyuan, Wasana; Grieco, John P; Bangs, Michael J; Prabaripai, Atchariya; Tantakom, Siripun; Chareonviriyaphap, Theeraphap

    2014-06-01

    An investigation of the behavioral responses of Aedes aegypti (= Stegomyia aegypti) to various concentrations of essential oils (2.5, 5, and 10%) extracted from hairy basil (Ocimum americanum Linn), ginger (Zingiber officinale Roscoe), lemongrass (Cymbopogon citratus Stapf), citronella grass (Cymbopogon nardus Rendle), and plai (Zingiber cassumunar Roxb) were performed using an excito-repellency test chamber. Results showed that Ae. aegypti exhibited varying levels of escape response in both the contact and noncontact chambers in response to different essential oils. The magnitude of the behaviors changed in a dose-response fashion depending on the percent volume to volume concentration of oil used. A 2.5% concentration of hairy basil oil produced a significantly greater escape response compared to the other extracts at the same concentration (P< 0.05). Oils of ginger, lemongrass, and citronella produced stronger irritant and repellent responses at the median 5% concentration compared to the lowest and highest concentrations. There was marked suppression of escape for both contact and noncontact tests using 10% concentrations of hairy basil, lemongrass, and citronella, with high knockdown for all three oils after 30 min. Hairy basil and lemongrass had the highest insecticidal activity to Ae. aegypti, with LC50 values of 6.3 and 6.7 percent, respectively. We conclude that the essential oils from native plants tested, and likely many other extracts found in plants, have inherent repellent and irritant qualities that should to be screened and optimized for their behavior-modifying properties against Ae. aegypti and other biting arthropods of public health and pest importance.

  12. Genetic Diversity and Phylogeny of Aedes aegypti, the Main Arbovirus Vector in the Pacific

    PubMed Central

    Calvez, Elodie; Guillaumot, Laurent; Millet, Laurent; Marie, Jérôme; Bossin, Hervé; Rama, Vineshwaran; Faamoe, Akata; Kilama, Sosiasi; Teurlai, Magali; Mathieu-Daudé, Françoise; Dupont-Rouzeyrol, Myrielle

    2016-01-01

    Background The Pacific region is an area unique in the world, composed of thousands of islands with differing climates and environments. The spreading and establishment of the mosquito Aedes aegypti in these islands might be linked to human migration. Ae. aegypti is the major vector of arboviruses (dengue, chikungunya and Zika viruses) in the region. The intense circulation of these viruses in the Pacific during the last decade led to an increase of vector control measures by local health authorities. The aim of this study is to analyze the genetic relationships among Ae. aegypti populations in this region. Methodology/Principal Finding We studied the genetic variability and population genetics of 270 Ae. aegypti, sampled from 9 locations in New Caledonia, Fiji, Tonga and French Polynesia by analyzing nine microsatellites and two mitochondrial DNA regions (CO1 and ND4). Microsatellite markers revealed heterogeneity in the genetic structure between the western, central and eastern Pacific island countries. The microsatellite markers indicate a statistically moderate differentiation (FST = 0.136; P < = 0.001) in relation to island isolation. A high degree of mixed ancestry can be observed in the most important towns (e.g. Noumea, Suva and Papeete) compared with the most isolated islands (e.g. Ouvea and Vaitahu). Phylogenetic analysis indicated that most of samples are related to Asian and American specimens. Conclusions/Significance Our results suggest a link between human migrations in the Pacific region and the origin of Ae. aegypti populations. The genetic pattern observed might be linked to the island isolation and to the different environmental conditions or ecosystems. PMID:26799213

  13. Costs of Three Wolbachia Infections on the Survival of Aedes aegypti Larvae under Starvation Conditions.

    PubMed

    Ross, Perran A; Endersby, Nancy M; Hoffmann, Ary A

    2016-01-01

    The mosquito Aedes aegypti, the principal vector of dengue virus, has recently been infected experimentally with Wolbachia: intracellular bacteria that possess potential as dengue biological control agents. Wolbachia depend on their hosts for nutrients they are unable to synthesize themselves. Consequently, competition between Wolbachia and their host for resources could reduce host fitness under the competitive conditions commonly experienced by larvae of Ae. aegypti in the field, hampering the invasion of Wolbachia into natural mosquito populations. We assess the survival and development of Ae. aegypti larvae under starvation conditions when infected with each of three experimentally-generated Wolbachia strains: wMel, wMelPop and wAlbB, and compare their fitness to wild-type uninfected larvae. We find that all three Wolbachia infections reduce the survival of larvae relative to those that are uninfected, and the severity of the effect is concordant with previously characterized fitness costs to other life stages. We also investigate the ability of larvae to recover from extended food deprivation and find no effect of Wolbachia on this trait. Aedes aegypti larvae of all infection types were able to resume their development after one month of no food, pupate rapidly, emerge at a large size, and exhibit complete cytoplasmic incompatibility and maternal transmission. A lowered ability of Wolbachia-infected larvae to survive under starvation conditions will increase the threshold infection frequency required for Wolbachia to establish in highly competitive natural Ae. aegypti populations and will also reduce the speed of invasion. This study also provides insights into survival strategies of larvae when developing in stressful environments.

  14. Field evaluation of a lethal ovitrap for the control of Aedes aegypti (Diptera: Culicidae) in Thailand.

    PubMed

    Sithiprasasna, Ratana; Mahapibul, Pradith; Noigamol, Chumnong; Perich, Michael J; Zeichner, Brian C; Burge, Bob; Norris, Sarah L W; Jones, James W; Schleich, Sonya S; Coleman, Russell E

    2003-07-01

    In 1999 and 2000 we evaluated a lethal ovitrap (LO) for the control of Aedes aegypti (L.) in three villages in Ratchaburi Province, Thailand. Two blocks of 50 houses (a minimum of 250 m apart) served as treatment and control sites in each village, with each house in the treatment area receiving 10 LOs. Thirty houses in the center of each treatment and control block were selected as sampling sites, with larval and adult mosquito sampling initiated when LOs were placed. Sampling was conducted weekly in 10 of the 30 houses at each site, with each block of 10 houses sampled every third week. Sampling continued for 30 wk. Efficacy of the LO was evaluated by determining number of containers with larvae and/or pupae per house and number of adult mosquitoes collected inside each house. In 1999, the LO had a negligible impact on all measures of Ae. aegypti abundance that were assessed; however, fungal contamination of insecticide-impregnated strips may have been responsible for the low efficacy. In 2000, significant suppression was achieved based on changes in multiple entomologic criteria (containers with larvae, containers with pupae, and number of adult Ae. aegypti); however, control was not absolute and neither immature nor adult Ae. aegypti were ever eliminated completely. We conclude that the LO can reduce adult Ae. aegypti populations in Thailand; however, efficacy of the LO is lower than desired due primarily to the high number of alternative oviposition sites. LO efficacy may be improved when used as part of an integrated control program that places emphasis on reduction of adjacent larval habitats. Further studies are required to assess this issue.

  15. Selective inhibitors of digestive enzymes from Aedes aegypti larvae identified by phage display.

    PubMed

    Soares, Tatiane Sanches; Soares Torquato, Ricardo Jose; Alves Lemos, Francisco Jose; Tanaka, Aparecida Sadae

    2013-01-01

    Dengue is a serious disease transmitted by the mosquito Aedes aegypti during blood meal feeding. It is estimated that the dengue virus is transmitted to millions of individuals each year in tropical and subtropical areas. Dengue control strategies have been based on controlling the vector, Ae. aegypti, using insecticide, but the emergence of resistance poses new challenges. The aim of this study was the identification of specific protease inhibitors of the digestive enzymes from Ae. aegypti larvae, which may serve as a prospective alternative biocontrol method. High affinity protein inhibitors were selected by all of the digestive serine proteases of the 4th instar larval midgut, and the specificity of these inhibitors was characterized. These inhibitors were obtained from a phage library displaying variants of HiTI, a trypsin inhibitor from Haematobia irritans, that are mutated in the reactive loop (P1-P4'). Based on the selected amino acid sequence pattern, seven HiTI inhibitor variants were cloned, expressed and purified. The results indicate that the HiTI variants named T6 (RGGAV) and T128 (WNEGL) were selected by larval trypsin-like (IC(50) of 1.1 nM) and chymotrypsin-like enzymes (IC(50) of 11.6 nM), respectively. The variants T23 (LLGGL) and T149 (GGVWR) inhibited both larval chymotrypsin-like (IC(50) of 4.2 nM and 29.0 nM, respectively) and elastase-like enzymes (IC(50) of 1.2 nM for both). Specific inhibitors were successfully obtained for the digestive enzymes of Ae. aegypti larvae by phage display. Our data also strongly suggest the presence of elastase-like enzymes in Ae. aegypti larvae. The HiTI variants T6 and T23 are good candidates for the development as a larvicide to control the vector.

  16. Costs of Three Wolbachia Infections on the Survival of Aedes aegypti Larvae under Starvation Conditions

    PubMed Central

    Ross, Perran A.; Endersby, Nancy M.; Hoffmann, Ary A.

    2016-01-01

    The mosquito Aedes aegypti, the principal vector of dengue virus, has recently been infected experimentally with Wolbachia: intracellular bacteria that possess potential as dengue biological control agents. Wolbachia depend on their hosts for nutrients they are unable to synthesize themselves. Consequently, competition between Wolbachia and their host for resources could reduce host fitness under the competitive conditions commonly experienced by larvae of Ae. aegypti in the field, hampering the invasion of Wolbachia into natural mosquito populations. We assess the survival and development of Ae. aegypti larvae under starvation conditions when infected with each of three experimentally-generated Wolbachia strains: wMel, wMelPop and wAlbB, and compare their fitness to wild-type uninfected larvae. We find that all three Wolbachia infections reduce the survival of larvae relative to those that are uninfected, and the severity of the effect is concordant with previously characterized fitness costs to other life stages. We also investigate the ability of larvae to recover from extended food deprivation and find no effect of Wolbachia on this trait. Aedes aegypti larvae of all infection types were able to resume their development after one month of no food, pupate rapidly, emerge at a large size, and exhibit complete cytoplasmic incompatibility and maternal transmission. A lowered ability of Wolbachia-infected larvae to survive under starvation conditions will increase the threshold infection frequency required for Wolbachia to establish in highly competitive natural Ae. aegypti populations and will also reduce the speed of invasion. This study also provides insights into survival strategies of larvae when developing in stressful environments. PMID:26745630

  17. Raw sewage as breeding site to Aedes (Stegomyia) aegypti (Diptera, culicidae).

    PubMed

    Chitolina, R F; Anjos, F A; Lima, T S; Castro, E A; Costa-Ribeiro, M C V

    2016-12-01

    The selection of oviposition sites by females of Aedes (Stegomyia) aegypti is a key factor for the larval survival and egg dispersion and has a direct influence in vector control programs. In this study, we evaluated the aspects of reproductive physiology of Ae. aegypti mosquitoes tested in the presence of raw sewage. Ae. aegypti females were used in oviposition bioassays according to two methodologies: (i) choice assay, in which three oviposition substrates were offered in the same cage: treatment (raw sewage), positive control (distilled water) and negative control (1% sodium hypochlorite) and; (ii) no choice assay, in which only one substrate was available. The physicochemical and microbiological analysis of the raw sewage used in this study indicated virtually no levels of chlorine, low levels of dissolved oxygen and high levels of nitrogenous compounds as well as the presence of Escherichia coli and total fecal coliforms. After 72h of oviposition, the eggs were counted and there was no statistically significant difference (p>0.05) in the oviposition rate between raw sewage and positive control in both methodologies. In addition, females were dissected to evaluate egg-retention and also there were no appreciable differences in egg retention even when raw sewage was the only substrate offered. The data also showed that egg hatching and larvae development occurred normally in the raw sewage. Therefore, the present study suggests that Ae. aegypti can adapt to new sites and lay eggs in polluted water, such as the raw sewage. These findings are of particular importance for the control and surveillance programs against Ae. aegypti in countries where the conditions of poor infrastructure and lack of basic sanitation are still an issue.

  18. The Siren's Song: Exploitation of Female Flight Tones to Passively Capture Male Aedes aegypti (Diptera: Culicidae).

    PubMed

    Johnson, Brian J; Ritchie, Scott A

    2016-01-01

    The need to capture male mosquitoes has intensified recently as a result of a number of male-based sterile insect technique (SIT) and population-modification programs focused on Aedes aegypti (L.) having initiated field releases. Here, we report the results of the successful exploitation of the attraction of male Ae. aegypti to female flight tones to enhance male collections in nonmechanical passive (nonbattery powered) Gravid Aedes Traps (GAT). Prior to field studies, male attraction to female flight tones of 484 and 560 Hz, as well as to a male flight tone of 715 Hz, were assessed in a series of controlled release-recapture and semifield trials. These trials determined that a pure tone of 484 Hz was significantly more attractive to free-flying males than the other flight tones and enabled their collection in sound-baited GATs (ca. 95% capture rate after 2 h; 484 Hz at 65 dB). In contrast, gravid females were unresponsive to male or female flight tones and were evenly distributed among sound-baited and control GATs. Importantly, under normal field conditions sound-baited GATs (484 Hz at 70 dB) captured significantly more male Ae. aegypti per 24-h trap interval (1.3 ± 0.37) than controls (0.2 ± 0.13). Overall, sound-bated GATs captured approximately twice as many Ae. aegypti (male and female; 3.0 ± 0.68 per interval, 30 total) than controls (1.5 ± 0.56 per interval, 15 total). These results reveal that sound-baited GATs are a simple and effective surveillance tool for Ae. aegypti that would allow current male-based SIT and population-modification programs to effectively monitor males in their target populations.

  19. Germ band retraction as a landmark in glucose metabolism during Aedes aegypti embryogenesis

    PubMed Central

    2010-01-01

    Background The mosquito A. aegypti is vector of dengue and other viruses. New methods of vector control are needed and can be achieved by a better understanding of the life cycle of this insect. Embryogenesis is a part of A. aegypty life cycle that is poorly understood. In insects in general and in mosquitoes in particular energetic metabolism is well studied during oogenesis, when the oocyte exhibits fast growth, accumulating carbohydrates, lipids and proteins that will meet the regulatory and metabolic needs of the developing embryo. On the other hand, events related with energetic metabolism during A. aegypti embryogenesis are unknown. Results Glucose metabolism was investigated throughout Aedes aegypti (Diptera) embryonic development. Both cellular blastoderm formation (CBf, 5 h after egg laying - HAE) and germ band retraction (GBr, 24 HAE) may be considered landmarks regarding glucose 6-phosphate (G6P) destination. We observed high levels of glucose 6-phosphate dehydrogenase (G6PDH) activity at the very beginning of embryogenesis, which nevertheless decreased up to 5 HAE. This activity is correlated with the need for nucleotide precursors generated by the pentose phosphate pathway (PPP), of which G6PDH is the key enzyme. We suggest the synchronism of egg metabolism with carbohydrate distribution based on the decreasing levels of phosphoenolpyruvate carboxykinase (PEPCK) activity and on the elevation observed in protein content up to 24 HAE. Concomitantly, increasing levels of hexokinase (HK) and pyruvate kinase (PK) activity were observed, and PEPCK reached a peak around 48 HAE. Glycogen synthase kinase (GSK3) activity was also monitored and shown to be inversely correlated with glycogen distribution during embryogenesis. Conclusions The results herein support the hypothesis that glucose metabolic fate changes according to developmental embryonic stages. Germ band retraction is a moment that was characterized as a landmark in glucose metabolism during Aedes

  20. Structure-Activity Relationship Studies on Natural Eremophilanes from Inula helenium as Toxicants Against Aedes aegypti Larvae and Adults

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An Aedes aegypti larval toxicity bioassay was performed on compounds representing many classes of natural compounds including polyacetylenes, phytosterols, flavonoids, sesquiterpenoids, and triterpenoids. Among these compounds studies, two eudesmanolides, alantolactone and isoalantolactone, showed l...

  1. Aedes aegypti (Diptera: Culicidae) Longevity and Differential Emergence of Dengue Fever in Two Cities in Sonora, Mexico.

    PubMed

    Ernst, Kacey C; Walker, Kathleen R; Reyes-Castro, Pablo; Joy, Teresa K; Castro-Luque, A Lucia; Diaz-Caravantes, Rolando E; Gameros, Mercedes; Haenchen, Steven; Hayden, Mary H; Monaghan, Andrew; Jeffrey-Guttierez, Eileen; Carrière, Yves; Riehle, Michael R

    2017-01-01

    Dengue virus, primarily transmitted by the Aedes aegypti (L.) mosquito, has rapidly expanded in geographic extent over the past several decades. In some areas, however, dengue fever has not emerged despite established Ae. aegypti populations. The reasons for this are unclear and have sometimes been attributed to socio-economic differences. In 2013 we compared Ae. aegypti adult density and population age structure between two cities in Sonora, Mexico: Hermosillo, which has regular seasonal dengue virus transmission, and Nogales, which has minimal transmission. Larval and pupal abundance was greater in Nogales, and adult density was only higher in Hermosillo during September. Population age structure, however, was consistently older in Hermosillo. This difference in longevity may have been one factor that limited dengue virus transmission in Nogales in 2013, as a smaller proportion of Ae. aegypti females survived past the extrinsic incubation period.

  2. Aedes aegypti (Diptera: Culicidae) Longevity and Differential Emergence of Dengue Fever in Two Cities in Sonora, Mexico.

    PubMed

    Ernst, Kacey C; Walker, Kathleen R; Reyes-Castro, Pablo; Joy, Teresa K; Castro-Luque, A Lucia; Diaz-Caravantes, Rolando E; Gameros, Mercedes; Haenchen, Steven; Hayden, Mary H; Monaghan, Andrew; Jeffrey-Guttierez, Eileen; Carrière, Yves; Riehle, Michael R

    2016-09-02

    Dengue virus, primarily transmitted by the Aedes aegypti (L.) mosquito, has rapidly expanded in geographic extent over the past several decades. In some areas, however, dengue fever has not emerged despite established Ae. aegypti populations. The reasons for this are unclear and have sometimes been attributed to socio-economic differences. In 2013 we compared Ae. aegypti adult density and population age structure between two cities in Sonora, Mexico: Hermosillo, which has regular seasonal dengue virus transmission, and Nogales, which has minimal transmission. Larval and pupal abundance was greater in Nogales, and adult density was only higher in Hermosillo during September. Population age structure, however, was consistently older in Hermosillo. This difference in longevity may have been one factor that limited dengue virus transmission in Nogales in 2013, as a smaller proportion of Ae. aegypti females survived past the extrinsic incubation period.

  3. Interspecific Cross-Mating Between Aedes aegypti and Aedes albopictus Laboratory Strains: Implication of Population Density on Mating Behaviors.

    PubMed

    Marcela, P; Hassan, A Abu; Hamdan, A; Dieng, H; Kumara, T K

    2015-12-01

    Mating behavior between Aedes aegypti and Ae. albopictus, established colony strains were examined under laboratory conditions (30-cm(3) screened cages) for 5 consecutive days. The effect of selected male densities (30, 20, 10) and female density (20) on the number of swarming, mating pairs, eggs produced, and inseminated females were evaluated. Male densities significantly increased swarming behavior, mating pairs, and egg production of heterospecific females, but female insemination was reduced. Aedes aegypti males mate more readily with heterospecific females than do Ae. albopictus males. The current study suggests that Ae. aegypti males were not species-specific in mating, and if released into the field as practiced in genetically modified mosquito techniques, they may mate with both Ae. aegypti and Ae. albopictus females, hence reducing populations of both species by producing infertile eggs.

  4. Field Efficacy of New Larvicide Products for Control of Multi-Resistant Aedes aegypti Populations in Martinique (French West Indies)

    PubMed Central

    Marcombe, Sébastien; Darriet, Frédéric; Agnew, Philip; Etienne, Manuel; Yp-Tcha, Marie-Michelle; Yébakima, André; Corbel, Vincent

    2011-01-01

    World-wide dengue vector control is hampered by the spread of insecticide resistance in Aedes aegypti. We report the resistance status of a wild Ae. aegypti population from Martinique (Vauclin) to conventional larvicides (Bacillus thuringiensis var israeliensis [Bti] and temephos) and potential alternatives (spinosad, diflubenzuron, and pyriproxyfen). The efficacy and residual activity of these insecticides were evaluated under simulated and field conditions. The Vauclin strain exhibited a high level of resistance to temephos, a tolerance to insect growth regulators, and full susceptibility to spinosad and Bti. In simulated trials, pyriproxyfen and Bti showed long residual activities in permanent breeding containers (28 and 37 weeks), whereas under field conditions they failed to curtail Ae. aegypti populations after four weeks. Conversely, diflubenzuron and spinosad showed a residual efficacy of 16 weeks, suggesting that these chemicals may be promising alternatives to Bti and temephos for controlling insecticide-resistant Ae. aegypti populations. PMID:21212213

  5. Spatial clustering of Aedes aegypti related to breeding container characteristics in Coastal Ecuador: implications for dengue control.

    PubMed

    Schafrick, Nathaniel H; Milbrath, Meghan O; Berrocal, Veronica J; Wilson, Mark L; Eisenberg, Joseph N S

    2013-10-01

    Mosquito management within households remains central to the control of dengue virus transmission. An important factor in these management decisions is the spatial clustering of Aedes aegypti. We measured spatial clustering of Ae. aegypti in the town of Borbón, Ecuador and assessed what characteristics of breeding containers influenced the clustering. We used logistic regression to assess the spatial extent of that clustering. We found strong evidence for juvenile mosquito clustering within 20 m and for adult mosquito clustering within 10 m, and stronger clustering associations for containers ≥ 40 L than those < 40 L. Aedes aegypti clusters persisted after adjusting for various container characteristics, suggesting that patterns are likely attributable to short dispersal distances rather than shared characteristics of containers in cluster areas. These findings have implications for targeting Ae. aegypti control efforts.

  6. Field efficacy of new larvicide products for control of multi-resistant Aedes aegypti populations in Martinique (French West Indies).

    PubMed

    Marcombe, Sébastien; Darriet, Frédéric; Agnew, Philip; Etienne, Manuel; Yp-Tcha, Marie-Michelle; Yébakima, André; Corbel, Vincent

    2011-01-01

    World-wide dengue vector control is hampered by the spread of insecticide resistance in Aedes aegypti. We report the resistance status of a wild Ae. aegypti population from Martinique (Vauclin) to conventional larvicides (Bacillus thuringiensis var israeliensis [Bti] and temephos) and potential alternatives (spinosad, diflubenzuron, and pyriproxyfen). The efficacy and residual activity of these insecticides were evaluated under simulated and field conditions. The Vauclin strain exhibited a high level of resistance to temephos, a tolerance to insect growth regulators, and full susceptibility to spinosad and Bti. In simulated trials, pyriproxyfen and Bti showed long residual activities in permanent breeding containers (28 and 37 weeks), whereas under field conditions they failed to curtail Ae. aegypti populations after four weeks. Conversely, diflubenzuron and spinosad showed a residual efficacy of 16 weeks, suggesting that these chemicals may be promising alternatives to Bti and temephos for controlling insecticide-resistant Ae. aegypti populations.

  7. Multi-scale analysis of the associations among egg, larval and pupal surveys and the presence and abundance of adult female Aedes aegypti (Stegomyia aegypti) in the city of Merida, Mexico.

    PubMed

    Manrique-Saide, P; Coleman, P; McCall, P J; Lenhart, A; Vázquez-Prokopec, G; Davies, C R

    2014-09-01

    Despite decades of research, there is still no agreement on which indices of Aedes aegypti (Stegomyia aegypti) (Diptera: Culicidae) presence and abundance better quantify entomological risk for dengue. This study reports the results of a multi-scale, cross-sectional entomological survey carried out in 1160 households in the city of Merida, Mexico to establish: (a) the correlation between levels of Ae. aegypti presence and abundance detected with aspirators and ovitraps; (b) which immature and egg indices correlate with the presence and abundance of Ae. aegypti females, and (c) the correlations amongst traditional Aedes indices and their modifications for pupae at the household level and within medium-sized geographic areas used for vector surveillance. Our analyses show that ovitrap positivity was significantly associated with indoor adult Ae. aegypti presence [odds ratio (OR) = 1.50; P = 0.03], that the presence of pupae is associated with adult presence at the household level (OR = 2.27; P = 0.001), that classic Aedes indices are informative only when they account for pupae, and that window screens provide a significant level of protection against peridomestic Ae. aegypti (OR = 0.59; P = 0.02). Results reinforce the potential of using both positive collections in outdoor ovitraps and the presence of pupae as sensitive indicators of indoor adult female presence.

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

    PubMed

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

    2010-06-01

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

  9. Cobertura de los sistemas de pensiones y factores asociados al acceso a una pensión de jubilación en México

    PubMed Central

    Murillo-López, Sandra; Venegas-Martínez, Francisco

    2016-01-01

    Resumen Objetivos: obtener estimaciones de indicadores de cobertura de las pensiones por jubilación o retiro para la población mexicana de 65 y más años, y evaluar el impacto que tienen los sistemas de pensiones en las transiciones al retiro de los adultos en edades medias y avanzadas en México. Para ello se utilizan datos microeconómicos provenientes de la Encuesta Nacional de Salud y Envejecimiento. Mediante análisis econométrico se identifican los factores sociodemográficos, económicos, laborales e institucionales que están asociados al acceso a una pensión de jubilación, o bien, a la dependencia de otras fuentes de ingresos. Se encontró que, en México, las transiciones al retiro del mercado de trabajo en las etapas avanzadas del ciclo de vida son limitadas debido a las características eminentemente contributivas de los esquemas de pensiones, los cuales favorecen a la población con trayectorias laborales formales y más estables asociadas a: características de género, oportunidades educativas y posibilidades de inserción en el mercado laboral. PMID:27524936

  10. Biological differences between brackish and fresh water-derived Aedes aegypti from two locations in the Jaffna peninsula of Sri Lanka and the implications for arboviral disease transmission.

    PubMed

    Ramasamy, Ranjan; Jude, Pavilupillai J; Veluppillai, Thabothiny; Eswaramohan, Thampoe; Surendran, Sinnathamby N

    2014-01-01

    The mainly fresh water arboviral vector Aedes aegypti L. (Diptera: Culicidae) can also undergo pre-imaginal development in brackish water of up to 15 ppt (parts per thousand) salt in coastal areas. We investigated differences in salinity tolerance, egg laying preference, egg hatching and larval development times and resistance to common insecticides in Ae. aegypti collected from brackish and fresh water habitats in Jaffna, Sri Lanka. Brackish water-derived Ae. aegypti were more tolerant of salinity than fresh water-derived Ae. aegypti and this difference was only partly reduced after their transfer to fresh water for up to five generations. Brackish water-derived Ae. aegypti did not significantly discriminate between 10 ppt salt brackish water and fresh water for oviposition, while fresh water-derived Ae. aegypti preferred fresh water. The hatching of eggs from both brackish and fresh water-derived Ae. aegypti was less efficient and the time taken for larvae to develop into pupae was prolonged in 10 ppt salt brackish water. Ae. aegypti isolated from coastal brackish water were less resistant to the organophosphate insecticide malathion than inland fresh water Ae. aegypti. Brackish and fresh water-derived Ae. aegypti however were able to mate and produce viable offspring in the laboratory. The results suggest that development in brackish water is characterised by pertinent biological changes, and that there is restricted genetic exchange between coastal brackish and inland fresh water Ae. aegypti isolates from sites 5 km apart. The findings highlight the need for monitoring Ae. aegypti developing in coastal brackish waters and extending vector control measures to their habitats.

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

    PubMed Central

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

    2011-01-01

    Objective To determine the ovicidal and repellent activities of methanol leaf extract of Ervatamia coronaria (E. coronaria) and Caesalpinia pulcherrima (C. pulcherrima) against Culex quinquefasciatus (Cx. quinquefasciatus), Aedes aegypti (Ae. aegypti) and Anopheles stephensi (An. stephensi). Methods The ovicidal activity was determined against three mosquito species at various concentrations ranging from 50-450 ppm under the laboratory conditions. The hatch rates were assessed 48 h after treatment. The repellent efficacy was determined against three mosquito species at three concentrations viz., 1.0, 2.5 and 5.0 mg/cm2 under the laboratory conditions. Results The crude extract of E. coronaria exerted zero hatchability (100% mortality) at 250, 200 and 150 ppm for Cx. quinquefasciatus, Ae. aegypti and An. stephensi, respectively. The crude extract of C. pulcherrima exerted zero hatchability (100% mortality) at 375, 300 and 225 ppm for Cx. quinquefasciatus, Ae. aegypti and An. Stephensi, respectively. The methanol extract of E. coronaria found to be more repellenct than C. pulcherrima extract. A higher concentration of 5.0 mg/cm2 provided 100% protection up to 150, 180 and 210 min against Cx. quinquefasciatus, Ae. aegypti and An. stephensi, respectively. The results clearly showed that repellent activity was dose dependent. Conclusions From the results it can be concluded the crude extracts of E. coronaria and C. pulcherrima are an excellent potential for controlling Cx. quinquefasciatus, Ae. aegypti and An. stephensi mosquitoes. PMID:23569723

  12. A Multipurpose, High-Throughput Single-Nucleotide Polymorphism Chip for the Dengue and Yellow Fever Mosquito, Aedes aegypti

    PubMed Central

    Evans, Benjamin R.; Gloria-Soria, Andrea; Hou, Lin; McBride, Carolyn; Bonizzoni, Mariangela; Zhao, Hongyu; Powell, Jeffrey R.

    2015-01-01

    The dengue and yellow fever mosquito, Aedes aegypti, contributes significantly to global disease burden. Genetic study of Aedes aegypti is essential to understanding its evolutionary history, competence as a disease vector, and the effects and efficacy of vector control methods. The prevalence of repeats and transposable elements in the Aedes aegypti genome complicates marker development and makes genome-wide genetic study challenging. To overcome these challenges, we developed a high-throughput genotyping chip, Axiom_aegypti1. This chip screens for 50,000 single-nucleotide polymorphisms present in Aedes aegypti populations from around the world. The array currently used genotypes 96 samples simultaneously. To ensure that these markers satisfy assumptions commonly made in many genetic analyses, we tested for Mendelian inheritance and linkage disequilibrium in laboratory crosses and a wild population, respectively. We have validated more than 25,000 of these markers to date, and expect this number to increase with more sampling. We also present evidence of the chip’s efficacy in distinguishing populations throughout the world. The markers on this chip are ideal for applications ranging from population genetics to genome-wide association studies. This tool makes rapid, cost-effective, and comparable genotype data attainable to diverse sets of Aedes aegypti researchers, from those interested in potential range shifts due to climate change to those characterizing the genetic underpinnings of its competence to transmit disease. PMID:25721127

  13. Adulticidal Activity of Olea vera, Linum usitatissimum and Piper nigera against Anopheles stephensi and Aedes aegypti under Laboratory Conditions

    PubMed Central

    Nawaz, R; Rathor, H Rashid; Bilal, H; Hassan, SA; Khan, I Akram

    2011-01-01

    Background: There are several plant extractions which are being used for mosquito control. The aim of this study was to evaluate the efficacy of Olea vera, Linum usitatissimum and Piper nigera against Anopheles stephensi and Aedes aegypti under laboratory conditions. Methods: These tests were carried out using WHO recommended bioassay method for adult mosquitoes. Results: The extracts from black pepper was more effective as adulticide with lowest LC50 values (2.26% and 8.4%) against Aedes aegypti and Anopheles stephensi after 24 h of exposure while after 48h (1.56% and 5.11%) respectively. In terms of LC90 value black pepper was best with (8.66% and 30.1%) against Ae. aegypti and An. stephensi after 24 h of exposure while after 48h (4.59% and 17.3%) respectively. In terms of LT50 black pepper took 15 h to kill 50% tested population of Ae. aegypti while against An. stephensi it took more than 2 days. In terms of percentage mortality black pepper kill 84% of the population of Ae. aegypti and 44.75% of the An. stephensi population. Conclusion: Black pepper showed best results in term of LC50, LC90, LT50 and percentage mortality against Ae. aegypti and An. stephensi. Our study suggested that the plant extracts have potential to kill adult mosquitoes, are environment friendly and can be used for the control of mosquitoes. PMID:22808413

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

    PubMed Central

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

    2011-01-01

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

  15. A Multipurpose, High-Throughput Single-Nucleotide Polymorphism Chip for the Dengue and Yellow Fever Mosquito, Aedes aegypti.

    PubMed

    Evans, Benjamin R; Gloria-Soria, Andrea; Hou, Lin; McBride, Carolyn; Bonizzoni, Mariangela; Zhao, Hongyu; Powell, Jeffrey R

    2015-02-26

    The dengue and yellow fever mosquito, Aedes aegypti, contributes significantly to global disease burden. Genetic study of Aedes aegypti is essential to understanding its evolutionary history, competence as a disease vector, and the effects and efficacy of vector control methods. The prevalence of repeats and transposable elements in the Aedes aegypti genome complicates marker development and makes genome-wide genetic study challenging. To overcome these challenges, we developed a high-throughput genotyping chip, Axiom_aegypti1. This chip screens for 50,000 single-nucleotide polymorphisms present in Aedes aegypti populations from around the world. The array currently used genotypes 96 samples simultaneously. To ensure that these markers satisfy assumptions commonly made in many genetic analyses, we tested for Mendelian inheritance and linkage disequilibrium in laboratory crosses and a wild population, respectively. We have validated more than 25,000 of these markers to date, and expect this number to increase with more sampling. We also present evidence of the chip's efficacy in distinguishing populations throughout the world. The markers on this chip are ideal for applications ranging from population genetics to genome-wide association studies. This tool makes rapid, cost-effective, and comparable genotype data attainable to diverse sets of Aedes aegypti researchers, from those interested in potential range shifts due to climate change to those characterizing the genetic underpinnings of its competence to transmit disease.

  16. Age-Stage, Two-Sex Life Table Characteristics of Aedes albopictus and Aedes Aegypti in Penang Island, Malaysia.

    PubMed

    Maimusa, Hamisu A; Ahmad, Abu Hassan; Kassim, Nur Faeza A; Rahim, Junaid

    2016-03-01

    The life table developmental attributes of laboratory colonies of wild strains of Aedes albopictus and Aedes aegypti were analyzed and compared based on the age-stage, two-sex life table. Findings inclusive in this study are: adult preoviposition periods, total preoviposition period, mean intrinsic rate of increase (r), mean finite rate of increase (λ), net reproductive rates (R0), and mean generation time (T). The total preadult development time was 9.47 days for Ae. albopictus and 8.76 days for Ae. aegypti. The life expectancy was 19.01 days for Ae. albopictus and 19.94 days for Ae. aegypti. Mortality occurred mostly during the adult stage. The mean development time for each stage insignificantly correlated with temperature for Ae. albopictus (r  =  -0.208, P > 0.05) and (r  =  -0.312, P > 0.05) for Ae. aegypti. The population parameters suggest that Ae. albopictus and Ae. aegypti populations are r-strategists characterized by a high r, a large R0, and short T. This present study provides the first report to compare the life parameters of Ae. albopictus and Ae. aegypti strains from Penang island, Malaysia.

  17. Toxicity studies for indigenous Bacillus thuringiensis isolates from Malang city, East Java on Aedes aegypti larvae

    PubMed Central

    Gama, Zulfaidah Penata; Nakagoshi, Nobukazu; Suharjono; Setyowati, Faridah

    2013-01-01

    Objective To investigate the toxicity of indigenous Bacillus thuringiensis (B. thuringiensis)isolates from Malang City for controlling Aedes aegypti (Ae. aegypti) larvae. Methods Soil samples were taken from Purwantoro and Sawojajar sub-districts. Bacterial isolation was performed using B. thuringiensis selective media. Phenotypic characteristics of the isolates were obtained with the simple matching method. The growth and prevalence of spores were determined by the Total Plate Count method, and toxicity tests were also performed on the third instar larval stage of Ae. aegypti. The percentage of larval mortality was analysed using probit regression. The LC50 was analysed by ANOVA, and the Tukey HSD interval was 95%. Results Among the 33 selected bacterial isolates, six were obtained (PWR4-31, PWR4-32, SWJ4-2b, SWJ4-4b, SWJ-4k and SWJ5-1) that had a similar phenotype to reference B. thuringiensis. Based on the dendrogram, all of the bacterial isolates were 71% similar. Three isolates that had a higher prevalence of reference B. thuringiensis were PWR4-32, SWJ4-4b and SW5-1, of which the spore prevalence was 52.44%, 23.59%, 34.46%, respectively. These three indigenous isolates from Malang City successfully killed Ae. aegypti larvae. The PWR4-32 isolates were the most effective at killing the larvae. Conclusions Six indigenous B. thuringiensis isolates among the 33 bacterial isolates found in the Sawojajar and Purwantoro sub-districts were toxic to the third instar larvae of Ae. aegypti. The PWR4-32 isolates were identical to the reference B. thuringiensis and had 88% phenotype similarity. The PWR4-32 isolates had the highest spore prevalence (52.44%), and the early stationary phase occurred at 36 h. The PWR4-32 isolates were the most effective at killing Ae. aegypti larvae (LC50-72 h=2.3×108 cells/mL). PMID:23593589

  18. Susceptibility profile of Aedes aegypti from Santiago Island, Cabo Verde, to insecticides.

    PubMed

    Rocha, Hélio Daniel Ribeiro; Paiva, Marcelo Henrique Santos; Silva, Norma Machado; de Araújo, Ana Paula; Camacho, Denise dos Reis da Rosa de Azevedo; Moura, Aires Januário Fernandes da; Gómez, Lara Ferrero; Ayres, Constância Flávia Junqueira; Santos, Maria Alice Varjal de Melo

    2015-12-01

    In 2009, Cabo Verde diagnosed the first dengue cases, with 21,137 cases reported and Aedes aegypti was identified as the vector. Since the outbreak, chemical insecticides and source reduction were used to control the mosquito population. This study aimed to assess the susceptibility of A. aegypti populations from Santiago, Cabo Verde to insecticides and identify the mechanisms of resistance. Samples of A. aegypti eggs were obtained at two different time periods (2012 and 2014), using ovitraps in different locations in Santiago Island to establish the parental population. F1 larvae were exposed to different concentrations of insecticides (Bacillus thuringiensis var israelensis (Bti), diflubenzuron and temephos) to estimate the lethal concentrations (LC90) and calculate the respective rate of resistance (RR90). Semi-field tests using temephos-ABATE(®) were performed to evaluate the persistence of the product. Bottle tests using female mosquitoes were carried out to determine the susceptibility to the adulticides malathion, cypermethrin and deltamethrin. Biochemical and molecular tests were performed to investigate the presence of metabolic resistance mechanisms, associated with the enzymes glutathione S-transferases (GSTs), esterases and mixed-function oxidases (MFO) and to detect mutations or alterations in the sodium channel and acetylcholinesterase genes. A. aegypti mosquitoes from Santiago exhibited resistance to deltamethrin, cypermethrin (mortality<80%) and temephos (RR90=4.4) but susceptibility to malathion (mortality≥98%), Bti and diflubenzuron. The low level of resistance to temephos did not affect the effectiveness of Abate(®). The enzymatic analysis conducted in 2012 revealed slight changes in the activities of GST (25%), MFO (18%), α-esterase (19%) and β-esterase (17%), but no significant changes in 2014. Target site resistance mutations were not detected. Our results suggest that the A. aegypti population from Santiago is resistant to two major

  19. Uso de Sustancias en Mujeres con Desventaja Social: Riesgo para el Contagio de VIH/SIDA

    PubMed Central

    Cianelli, R.; Ferrer, L; Bernales, M.; Miner, S.; Irarrázabal, L.; Molina, Y.

    2009-01-01

    Antecedentes La caracterización epidemiológica en Chile apunta a feminización, pauperización y heterosexualización de la epidemia del VIH, lo que implica un mayor riesgo para las mujeres en desventaja social. Si a esto se suma la utilización de sustancias, la vulnerabilidad de este grupo frente al VIH/SIDA aumenta. Objetivo Describir el uso de sustancias en mujeres con desventaja social e identificar factores de riesgo de contagio de VIH, asociados a este consumo. Material y Método 52 mujeres fueron entrevistadas como parte del proyecto “Testeando una intervención en prevención de VIH/SIDA en mujeres chilenas” GRANT # RO1 TW 006977. Se describen variables sociodemográficas y de consumo de sustancias a través de estadísticas descriptivas y se analiza la relación entre variables a través de pruebas de correlación. Resultados Los resultados indican un perfil sociodemográfico que sitúa a las mujeres en situación de vulnerabilidad frente al contagio de VIH/SIDA, con alto índice de uso de sustancias que acentúa el riesgo. Conclusiones Los hallazgos apuntan a la necesidad de considerar intervenciones que se enfoquen en la prevención de VIH en mujeres, abordando los riesgos asociados al consumo de sustancias. PMID:21197380

  20. A field test for competitive effects of Aedes albopictus on A. aegypti in South Florida: differences between sites of coexistence and exclusion?

    PubMed Central

    Juliano, Steven A.; Lounibos, L. Philip; O’Meara, George F.

    2007-01-01

    We tested whether interspecific competition from Aedes albopictus had measurable effects on A. aegypti at the typical numbers of larval mosquitoes found in cemetery vases in south Florida. We also tested whether the effect of interspecific competition from A. albopictus on A. aegypti differed between sites where A. aegypti either persists or went extinct following invasion by A. albopictus. Similar experiments manipulating numbers of A. albopictus in cemetery vases were conducted at three sites of A. aegypti persistence and three sites where A. aegypti was apparently extinct. The experiments were done using numbers of larvae that were determined by observed numbers of larvae for each site, and with resources (leaf detritus) that accumulated in experimental vases placed into each field site. In both the early rainy season (when number of mosquito larvae was low) and the late rainy season (when number of mosquito larvae was high), there was a significant effect of treatment on developmental progress of experimental A. aegypti. In the late rainy season, when numbers of larvae were high, there was also a significant effect of treatment on survivorship of A. aegypti. However, the competition treatment × site type (A. aegypti persists vs extinct) interaction was never significant, indicating that the competitive effect of A. albopictus on A. aegypti did not differ systematically between persistence versus extinction sites. Thus, although competition from A. albopictus is strong under field conditions at all sites, we find no evidence that variation in the impact of interspecific competition is associated with coexistence or exclusion. Interspecific competition among larvae is thus a viable explanation for exclusion or reduction of A. aegypti in south Florida, but variation in the persistence of A. aegypti following invasion does not seem to be primarily a product of variation in the conditions in the aquatic environments of cemetery vases. PMID:15024640

  1. Influence of plant abundance on nectar feeding by Aedes aegypti (Diptera: Culicidae) in southern Mexico.

    PubMed

    Martinez-Ibarra, J A; Rodriguez, M H; Arredondo-Jimenez, J I; Yuval, B

    1997-11-01

    The availability of flowering plants affected the sugar feeding rates of female Aedes aegypti (L.) in 4 areas of a small city in southern Mexico. The proportion of mosquitoes containing sugar varied from 8 to 21% in 4 areas in direct relation to blooming plant abundance. Human density was similar in the 4 areas (range, 3.9-5.4 per house), whereas the number of flowering plants per house increased on the outskirts (range, 3.1-5.4 plants per house). Equal proportions of sugar positive females were nulliparous or parous, indicating similar sugar feeding at any age. In addition, nearly 60% of positive females were at the Christophers stage II, indicating a greater need for flight fuel during the early stages of egg development. We conclude that Ae. aegypti feeds frequently on nectar and that this activity is modulated by nectar availability.

  2. Influence of breeding site availability on the oviposition behaviour of Aedes aegypti.

    PubMed

    Abreu, Filipe Vieira Santos de; Morais, Maira Moreira; Ribeiro, Sérvio Pontes; Eiras, Álvaro Eduardo

    2015-08-01

    Despite the importance of the mosquito Aedes aegypti in the transmission of arboviruses, such as yellow fever, Chikungunya fever and dengue fever, some aspects of their behaviour remain unknown. In the present study, the oviposition behaviour of Ae. aegypti females that were exposed to different densities of breeding sites (2, 4, 8 and 16) was evaluated in laboratory and semi-field conditions. The number of breeding sites that were used was proportional to the number available, but tended towards stabilisation. Females used four-six breeding sites on average, with a maximum of 11. A high percentage of eggs was observed in the water, along with the presence of a breeding site termed "favourite", which received at least 40% of the eggs. The results are discussed in ecological, evolutionary and epidemiological approaches.

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

    PubMed Central

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

    2015-01-01

    This study investigated the toxic effects of essential oils isolated from Siparuna guianensis against Aedes aegypti, Culex quinquefasciatus (eggs, larvae, pupae, and adult) and Aedes albopictus (C6/36) cells. The oviposition-deterring activity, egg viability, and repellence activity in the presence of different essential oils concentrations were determined. The essential oils showed high toxicity to all developmental stages of A. aegypti and C. quinquefasciatus. Furthermore, the oils also showed high repellent activity towards the adult stage of mosquitoes (0.025 to 0.550 μg/cm2 skin conferred 100% repellence up to 120 min) and in contact with cultured insect cells (C6/36) induced death possibly by necrosis. The results presented in this work show the potential of S. guianensis essential oils for the development of an alternative and effective method for the natural control of mosquitoes in homes and urban areas. PMID:25646797

  4. Characterization of the oxysterol-binding protein gene family in the yellow fever mosquito, Aedes aegypti

    PubMed Central

    Fu, Qiang; Lynn-Miller, Ace; Lan, Que

    2011-01-01

    The oxysterol-binding protein (OSBP) and related proteins (ORPs) are sterol-binding proteins that may be involved in cellular sterol transportation, sterol metabolism and signal transduction pathways. Four ORP genes were cloned from Aedes aegypti. Based on amino acid sequence homology to human proteins, they are AeOSBP, AeORP1, AeORP8 and AeORP9. Splicing variants of AeOSBP and AeORP8 were identified. The temporal and spatial transcription patterns of members of the AeOSBP gene family through developmental stages and the gonotrophic cycle were profiled. AeORP1 transcription seemed to be head tissue-specific, whereas AeOSBP and AeORP9 expressions were induced by a blood meal. Furthermore, over-expression of AeORPs facilitated [3H]-cholesterol uptake in Aedes aegypti cultured Aag-2 cells. PMID:21699592

  5. Data documenting the potential distribution of Aedes aegypti in the center of Veracruz, Mexico.

    PubMed

    Estrada-Contreras, Israel; Sandoval-Ruiz, César A; Mendoza-Palmero, Fredy S; Ibáñez-Bernal, Sergio; Equihua, Miguel; Benítez, Griselda

    2017-02-01

    The data presented in this article are related to the research article entitled "Establishment of Aedes aegypti (L.) in mountainous regions in Mexico: Increasing number of population at risk of mosquito-borne disease and future climate conditions" (M. Equihua, S. Ibáñez-Bernal, G. Benítez, I. Estrada-Contreras, C.A. Sandoval-Ruiz, F.S. Mendoza-Palmero, 2016) [1]. This article provides presence records in shapefile format used to generate maps of potential distribution of Aedes aegypti with different climate change scenarios as well as each of the maps obtained in raster format. In addition, tables with values of potential distribution of the vector as well as the average values of probability of presence including data of the mosquito incidence along the altitudinal range.

  6. Leaking Containers: Success and Failure in Controlling the Mosquito Aedes aegypti in Brazil.

    PubMed

    Löwy, Ilana

    2017-04-01

    In 1958, the Pan American Health Organization declared that Brazil had successfully eradicated the mosquito Aedes aegypti, responsible for the transmission of yellow fever, dengue fever, chikungunya, and Zika virus. Yet in 2016 the Brazilian minister of health described the situation of dengue fever as "catastrophic." Discussing the recent epidemic of Zika virus, which amplified the crisis produced by the persistence of dengue fever, Brazil's president declared in January 2016 that "we are in the process of losing the war against the mosquito Aedes aegypti." I discuss the reasons for the failure to contain Aedes in Brazil and the consequences of this failure. A longue durée perspective favors a view of the Zika epidemic that does not present it as a health crisis to be contained with a technical solution alone but as a pathology that has the persistence of deeply entrenched structural problems and vulnerabilities.

  7. SEX DETERMINATION. A male-determining factor in the mosquito Aedes aegypti.

    PubMed

    Hall, Andrew Brantley; Basu, Sanjay; Jiang, Xiaofang; Qi, Yumin; Timoshevskiy, Vladimir A; Biedler, James K; Sharakhova, Maria V; Elahi, Rubayet; Anderson, Michelle A E; Chen, Xiao-Guang; Sharakhov, Igor V; Adelman, Zach N; Tu, Zhijian

    2015-06-12

    Sex determination in the mosquito Aedes aegypti is governed by a dominant male-determining factor (M factor) located within a Y chromosome-like region called the M locus. Here, we show that an M-locus gene, Nix, functions as an M factor in A. aegypti. Nix exhibits persistent M linkage and early embryonic expression, two characteristics required of an M factor. Nix knockout with clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 resulted in largely feminized genetic males and the production of female isoforms of two key regulators of sexual differentiation: doublesex and fruitless. Ectopic expression of Nix resulted in genetic females with nearly complete male genitalia. Thus, Nix is both required and sufficient to initiate male development. This study provides a foundation for mosquito control strategies that convert female mosquitoes into harmless males.

  8. Indoor volatiles of primary school classrooms in Tapachula, Chiapas, Mexico, are attractants to Aedes aegypti females.

    PubMed

    Torres Estrada, José Luis; Ríos Delgado, Silvany Mayoly; Takken, Willem

    2013-09-01

    We determined the behavioral response of Aedes aegypti females to volatile compounds collected in indoor primary school classrooms. Volatiles were collected from classrooms from 0800 through 1030 h and 1130 through 1400 h in urban and rural schools in Tapachula, Chiapas, Mexico. Female responses to volatiles were assessed in a Y-tube olfactometer. Chemical compounds were identified using gas chromatography-mass spectrometer analysis. Volatiles from both schools were attractive when compared against their control. When such volatiles were compared, those from the rural school were more attractive than the ones from the urban school. Chromatographic profiles were similar between schools; however, the rural school showed more compounds. Attraction of Ae. aegypti females toward volatiles of primary school classrooms might increase dengue transmission probabilities in those sites.

  9. Image segmentation of ovitraps for automatic counting of Aedes Aegypti eggs.

    PubMed

    Mello, Carlos A B; dos Santos, Wellington P; Rodrigues, Marco A B; Candeias, Ana Lúcia B; Gusmão, Cristine M G

    2008-01-01

    The Aedes Aegypti mosquito is the vector of the most difficult public health problems in tropical and semi-tropical world: the epidemic proliferation of dengue, a viral disease that can cause human beings death specially in its most dangerous form, dengue haemorrhagic fever. One of the most useful methods for mosquito detection and surveillance is the ovitraps: special traps to collect eggs of the mosquito. It is very important to count the number of Aedes Aegypti eggs present in ovitraps. This counting is usually performed in a manual, visual and non-automatic form. This work approaches the development of automatic methods to count the number of eggs in ovitraps images using image processing, particularly color segmentation and mathematical morphology-based non-linear filters.

  10. Influence of breeding site availability on the oviposition behaviour of Aedes aegypti

    PubMed Central

    de Abreu, Filipe Vieira Santos; Morais, Maira Moreira; Ribeiro, Sérvio Pontes; Eiras, Álvaro Eduardo

    2015-01-01

    Despite the importance of the mosquito Aedes aegypti in the transmission of arboviruses, such as yellow fever, Chikungunya fever and dengue fever, some aspects of their behaviour remain unknown. In the present study, the oviposition behaviour of Ae. aegypti females that were exposed to different densities of breeding sites (2, 4, 8 and 16) was evaluated in laboratory and semi-field conditions. The number of breeding sites that were used was proportional to the number available, but tended towards stabilisation. Females used four-six breeding sites on average, with a maximum of 11. A high percentage of eggs was observed in the water, along with the presence of a breeding site termed “favourite”, which received at least 40% of the eggs. The results are discussed in ecological, evolutionary and epidemiological approaches. PMID:26154742

  11. Assessing the Feasibility of Controlling Aedes aegypti with Transgenic Methods: A Model-Based Evaluation

    PubMed Central

    Legros, Mathieu; Xu, Chonggang; Okamoto, Kenichi; Scott, Thomas W.; Morrison, Amy C.; Lloyd, Alun L.; Gould, Fred

    2012-01-01

    Suppression of dengue and malaria through releases of genetically engineered mosquitoes might soon become feasible. Aedes aegypti mosquitoes carrying a conditionally lethal transgene have recently been used to suppress local vector populations in small-scale field releases. Prior to releases of transgenic insects on a wider scale, however, most regulatory authorities will require additional evidence that suppression will be effective in natural heterogeneous habitats. We use a spatially explicit stochastic model of an Ae. aegypti population in Iquitos, Peru, along with an uncertainty analysis of its predictions, to quantitatively assess the outcome of varied operational approaches for releases of transgenic strains with conditional death of females. We show that population elimination might be an unrealistic objective in heterogeneous populations. We demonstrate that substantial suppression can nonetheless be achieved if releases are deployed in a uniform spatial pattern using strains combining multiple lethal elements, illustrating the importance of detailed spatial models for guiding genetic mosquito control strategies. PMID:23284949

  12. Repellence of essential oils of aromatic plants growing in Argentina against Aedes aegypti (Diptera: Culicidae).

    PubMed

    Gleiser, Raquel M; Bonino, Maria A; Zygadlo, Julio A

    2011-01-01

    Mosquitoes are vectors of pathogens to humans and domestic animals and may also have economical impacts. One approach to prevent mosquito-borne diseases is bite deterrence through the application of repellents. Currently, there is an interest to search for alternative bioactive products to the synthetic active ingredients most widely used in insect repellents. Repellence against Aedes aegypti of essential oils extracted from Acantholippia salsoloides, Aloysia catamarcensis, Aloysia polystachya, Lippia integrifolia, Lippia junelliana (Verbenaceae), Baccharis salicifolia, Euphatorium buniifolium, and Tagetes filifolia (Asteraceae) were assessed. Tests were conducted by alternatively exposing untreated and treated forehand to the mosquitoes and counting probing attempts. All essential oils tested were significantly repellent against A. aegypti when compared to untreated controls; L. junelliana was the most repellent and T. filifolia was the least based on the response of the mosquitoes to different concentrations of the essential oils (EO). Repellence may be attributed to the respective main components of each EO.

  13. Site-Specific Cassette Exchange Systems in the Aedes aegypti Mosquito and the Plutella xylostella Moth

    PubMed Central

    Haghighat-Khah, Roya Elaine; Scaife, Sarah; Martins, Sara; St John, Oliver; Matzen, Kelly Jean; Morrison, Neil; Alphey, Luke

    2015-01-01

    Genetically engineered insects are being evaluated as potential tools to decrease the economic and public health burden of mosquitoes and agricultural pest insects. Here we describe a new tool for the reliable and targeted genome manipulation of pest insects for research and field release using recombinase mediated cassette exchange (RMCE) mechanisms. We successfully demonstrated the established ΦC31-RMCE method in the yellow fever mosquito, Aedes aegypti, which is the first report of RMCE in mosquitoes. A new variant of this RMCE system, called iRMCE, combines the ΦC31-att integration system and Cre or FLP-mediated excision to remove extraneous sequences introduced as part of the site-specific integration process. Complete iRMCE was achieved in two important insect pests, Aedes aegypti and the diamondback moth, Plutella xylostella, demonstrating the transferability of the system across a wide phylogenetic range of insect pests. PMID:25830287

  14. Territorial analysis of Aedes aegypti distribution in two Colombian cities: a chorematic and ecosystem approach.

    PubMed

    Fuentes-Vallejo, Mauricio; Higuera-Mendieta, Diana Rocío; García-Betancourt, Tatiana; Alcalá-Espinosa, Lucas Andrés; García-Sánchez, Diana; Munévar-Cagigas, David Alejandro; Brochero, Helena Luisa; González-Uribe, Catalina; Quintero, Juliana

    2015-03-01

    A territorial analysis of Aedes aegypti density was conducted in two Colombian cities using an ecosystem and chorematic approach. Entomological and behavioral data (by cluster) and information on the urban context were used to analyze the relationship between territorial structures and dynamics and vector density. The results were represented in graphic (chorematic) models. Arauca showed higher vector density than Armenia. Higher density was related to unplanned urbanization, flood-prone areas, low socioeconomic strata, household water tanks, higher temperature, and recall of control measures for adult mosquitos. Zones with low density indices coincided with diverse socioeconomic, ecological, and behavioral conditions. The study found a relationship between territorial structures and dynamics and vector density in both Arauca and Armenia, where the interaction between ecological and social systems shape areas with high and low A. aegypti density.

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

    PubMed Central

    Sritabutra, Duangkamon; Soonwera, Mayura

    2013-01-01

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

  16. Weather Variability Associated with Aedes (Stegomyia) aegypti (Dengue Vector) Oviposition Dynamics in Northwestern Argentina.

    PubMed

    Estallo, Elizabet L; Ludueña-Almeida, Francisco F; Introini, María V; Zaidenberg, Mario; Almirón, Walter R

    2015-01-01

    This study aims to develop a forecasting model by assessing the weather variability associated with seasonal fluctuation of Aedes aegypti oviposition dynamic at a city level in Orán, in northwestern Argentina. Oviposition dynamics were assessed by weekly monitoring of 90 ovitraps in the urban area during 2005-2007. Correlations were performed between the number of eggs collected weekly and weather variables (rainfall, photoperiod, vapor pressure of water, temperature, and relative humidity) with and without time lags (1 to 6 weeks). A stepwise multiple linear regression analysis was performed with the set of meteorological variables from the first year of study with the variables in the time lags that best correlated with the oviposition. Model validation was conducted using the data from the second year of study (October 2006- 2007). Minimum temperature and rainfall were the most important variables. No eggs were found at temperatures below 10 °C. The most significant time lags were 3 weeks for minimum temperature and rains, 3 weeks for water vapor pressure, and 6 weeks for maximum temperature. Aedes aegypti could be expected in Orán three weeks after rains with adequate min temperatures. The best-fit forecasting model for the combined meteorological variables explained 70 % of the variance (adj. R(2)). The correlation between Ae. aegypti oviposition observed and estimated by the forecasting model resulted in rs = 0.80 (P < 0.05). The forecasting model developed would allow prediction of increases and decreases in the Ae. aegypti oviposition activity based on meteorological data for Orán city and, according to the meteorological variables, vector activity can be predicted three or four weeks in advance.

  17. Identification of Aedes aegypti and Its Respective Life Stages by Real-Time Polymerase Chain Reaction

    DTIC Science & Technology

    2004-12-01

    potential disease transmission risk and timely implementation of appropriate control measures, Aedes aegypti is the primary vector of dengue fever and...8217 Dengue fever is the most significant mosquito-borne viral disease today, with a risk comparable to that for malaria, i,e,, two-fifths of the world’s...human population, ’̂̂ Although malarial disease can be prevented by prophylaxis and yellow fever by immunization, dengue fever prophylaxis does not

  18. Effective disposal of nitrogen waste in blood-fed Aedes aegypti mosquitoes requires alanine aminotransferase

    PubMed Central

    Mazzalupo, Stacy; Isoe, Jun; Belloni, Virginia; Scaraffia, Patricia Y.

    2016-01-01

    To better understand the mechanisms responsible for the success of female mosquitoes in their disposal of excess nitrogen, we investigated the role of alanine aminotransferase (ALAT) in blood-fed Aedes aegypti. Transcript and protein levels from the 2 ALAT genes were analyzed in sucrose- and blood-fed A. aegypti tissues. ALAT1 and ALAT2 exhibit distinct expression patterns in tissues during the first gonotrophic cycle. Injection of female mosquitoes with either double-stranded RNA (dsRNA)-ALAT1 or dsRNA ALAT2 significantly decreased mRNA and protein levels of ALAT1 or ALAT2 in fat body, thorax, and Malpighian tubules compared with dsRNA firefly luciferase-injected control mosquitoes. The silencing of either A. aegypti ALAT1 or ALAT2 caused unexpected phenotypes such as a delay in blood digestion, a massive accumulation of uric acid in the midgut posterior region, and a significant decrease of nitrogen waste excretion during the first 48 h after blood feeding. Concurrently, the expression of genes encoding xanthine dehydrogenase and ammonia transporter (Rhesus 50 glycoprotein) were significantly increased in tissues of both ALAT1- and ALAT2-deficient females. Moreover, perturbation of ALAT1 and ALAT2 in the female mosquitoes delayed oviposition and reduced egg production. These novel findings underscore the efficient mechanisms that blood-fed mosquitoes use to avoid ammonia toxicity and free radical damage.—Mazzalupo, S., Isoe, J., Belloni, V., Scaraffia, P. Y. Effective disposal of nitrogen waste in blood-fed Aedes aegypti mosquitoes requires alanine aminotransferase. PMID:26310269

  19. Toxicity of spinosad to temephos-resistant Aedes aegypti populations in Brazil.

    PubMed

    Dos Santos Dias, Luciana; Macoris, Maria de Lourdes da Graça; Andrighetti, Maria Teresa Macoris; Otrera, Vanessa Camargo Garbeloto; Dias, Adriana Dos Santos; Bauzer, Luiz Guilherme Soares da Rocha; Rodovalho, Cynara de Melo; Martins, Ademir Jesus; Lima, José Bento Pereira

    2017-01-01

    The mosquito Aedes aegypti is the primary vector of different arboviruses and represents a major public health problem. Several Brazilian populations of Ae. aegypti have developed resistance to temephos, the most used organophosphate larvicide. New tools which are less harmful to the environment and safer for humans are becoming increasingly important to control this insect vector. Spinosad, an aerobic fermentation product of a soil actinobacteria, has a favorable environmental profile. It presents selective insecticide properties, a mechanism of action that differs from those of many synthetic chemical insecticides. The toxicity of spinosad and temephos to Aedes aegypti populations from Brazil, which were previously exposed to temephos, were investigated in this study. Larval susceptibility (LC50) to temephos varied from 3μg/L for Rockefeller up to 260 μg/L for Santana do Ipanema field derived population. Larval susceptibility (LC50) to spinosad varied from 23μg/L for Rockefeller up to 93μg/L for Marilia field derived population. In addition, a semi-field trial was performed to evaluate spinosad (NatularTM DT) initial efficacy and persistence toward four field-derived lineages and the Rockefeller lineage, used as an internal control. Spinosad was tested at 0.5mg active ingredient/L in 200L capacity water tanks. Mortality was recorded each 24 hours after exposition and tanks were further recolonized once per week with mortality being recorded daily for eight weeks. Spinosad provided a level equal or superior to 80% mortality during a seven to eight week evaluation period. The assessed populations did not present cross-resistance between spinosad and temephos in laboratory conditions. It demonstrates that spinosad may be a promising larvicide for the control of Ae. aegypti, especially for populations in which resistance to temephos has been detected.

  20. Comparison of wing geometry data and genetic data for assessing the population structure of Aedes aegypti.

    PubMed

    Vidal, Paloma Oliveira; Suesdek, Lincoln

    2012-04-01

    Aedes aegypti is the most important vector of dengue viruses in tropical and subtropical regions. Because vaccines are still under development, dengue prevention depends primarily on vector control. Population genetics is a common approach in research involving Ae. aegypti. In the context of medical entomology, wing morphometric analysis has been proposed as a strong and low-cost complementary tool for investigating population structure. Therefore, we comparatively evaluated the genetic and phenotypic variability of population samples of Ae. aegypti from four sampling sites in the metropolitan area of São Paulo city, Brazil. The distances between the sites ranged from 7.1 to 50 km. This area, where knowledge on the population genetics of this mosquito is incipient, was chosen due to the thousands of dengue cases registered yearly. The analysed loci were polymorphic, and they revealed population structure (global F(ST)=0.062; p<0.05) and low levels of gene flow (Nm=0.47) between the four locations. Principal component and discriminant analyses of wing shape variables (18 landmarks) demonstrated that wing polymorphisms were only slightly more common between populations than within populations. Whereas microsatellites allowed for geographic differentiation, wing geometry failed to distinguish the samples. These data suggest that microevolution in this species may affect genetic and morphological characters to different degrees. In this case, wing shape was not validated as a marker for assessing population structure. According to the interpretation of a previous report, the wing shape of Ae. aegypti does not vary significantly because it is stabilised by selective pressure.

  1. Bioefficacy of Mentha piperita essential oil against dengue fever mosquito Aedes aegypti L

    PubMed Central

    Kumar, Sarita; Wahab, Naim; Warikoo, Radhika

    2011-01-01

    Objective To assess the larvicidal and repellent potential of the essential oil extracted from the leaves of peppermint plant, Mentha piperita (M. piperita) against the larval and adult stages of Aedes aegypti (Ae. Aegypti). Methods The larvicidal potential of peppermint oil was evaluated against early fourth instar larvae of Ae. aegypti using WHO protocol. The mortality counts were made after 24 and 48 h, and LC50 and LC90 values were calculated. The efficacy of peppermint oil as mosquito repellent was assessed using the human-bait technique. The measured area of one arm of a human volunteer was applied with the oil and the other arm was applied with ethanol. The mosquito bites on both the arms were recorded for 3 min after every 15 min. The experiment continued for 3 h and the percent protection was calculated. Results The essential oil extracted from M. piperita possessed excellent larvicidal efficiency against dengue vector. The bioassays showed an LC50 and LC90 value of 111.9 and 295.18 ppm, respectively after 24 h of exposure. The toxicity of the oil increased 11.8% when the larvae were exposed to the oil for 48 h. The remarkable repellent properties of M. piperita essential oil were established against adults Ae. aegypti. The application of oil resulted in 100% protection till 150 min. After next 30 min, only 1-2 bites were recorded as compared with 8-9 bites on the control arm. Conclusions The peppermint essential oil is proved to be efficient larvicide and repellent against dengue vector. Further studies are needed to identify the possible role of oil as adulticide, oviposition deterrent and ovicidal agent. The isolation of active ingredient from the oil could help in formulating strategies for mosquito control. PMID:23569733

  2. Insecticide resistance in two Aedes aegypti (Diptera: Culicidae) strains from Costa Rica.

    PubMed

    Bisset, J A; Marín, R; Rodríguez, M M; Severson, D W; Ricardo, Y; French, L; Díaz, M; Pérez, O

    2013-03-01

    Dengue (family Flaviridae, genus Flavivirus, DENV) and dengue hemorrhagic fever (DHF) are presently important public health problems in Costa Rica. The primary strategy for disease control is based on reducing population densities of the main mosquito vector Aedes aegypti (L.) (Diptera: Culicidae). This is heavily dependent on use of chemical insecticides, thus the development of resistance is a frequent threat to control program effectiveness. The objective of this study was to determine the levels of insecticide resistance and the metabolic resistance mechanisms involved in two Ae. aegypti strains collected from two provinces (Puntarenas and Limon) in Costa Rica. Bioassays with larvae were performed according to World Health Organization guidelines and resistance in adults was measured through standard bottle assays. The activities of beta-esterases, cytochrome P450 monooxygenases, and glutathione S-transferases (GST), were assayed through synergists and biochemical tests, wherein the threshold criteria for each enzyme was established using the susceptible Rockefeller strain. The results showed higher resistance levels to the organophosphate (OP) temephos and the pyrethroid deltamethrin in larvae. The efficacy of commercial formulations of temephos in controlling Ae. aegypti populations was 100% mortality up to 11 and 12 d posttreatment with daily water replacements in test containers. Temephos and deltamethrin resistance in larvae were associated with high esterase activity, but not to cytochrome P450 monooxygenase or GST activities. Adult mosquitoes were resistant to deltamethrin, and susceptible to bendiocarb, chlorpyrifos, and cypermethrin. Because temephos and deltamethrin resistance are emerging at the studied sites, alternative insecticides should be considered. The insecticides chlorpyrifos and cypermethrin could be good candidates to use as alternatives for Ae. aegypti control.

  3. Toxicity of spinosad to temephos-resistant Aedes aegypti populations in Brazil

    PubMed Central

    dos Santos Dias, Luciana; Macoris, Maria de Lourdes da Graça; Andrighetti, Maria Teresa Macoris; Otrera, Vanessa Camargo Garbeloto; Dias, Adriana dos Santos; Bauzer, Luiz Guilherme Soares da Rocha; Rodovalho, Cynara de Melo; Martins, Ademir Jesus; Lima, José Bento Pereira

    2017-01-01

    The mosquito Aedes aegypti is the primary vector of different arboviruses and represents a major public health problem. Several Brazilian populations of Ae. aegypti have developed resistance to temephos, the most used organophosphate larvicide. New tools which are less harmful to the environment and safer for humans are becoming increasingly important to control this insect vector. Spinosad, an aerobic fermentation product of a soil actinobacteria, has a favorable environmental profile. It presents selective insecticide properties, a mechanism of action that differs from those of many synthetic chemical insecticides. The toxicity of spinosad and temephos to Aedes aegypti populations from Brazil, which were previously exposed to temephos, were investigated in this study. Larval susceptibility (LC50) to temephos varied from 3μg/L for Rockefeller up to 260 μg/L for Santana do Ipanema field derived population. Larval susceptibility (LC50) to spinosad varied from 23μg/L for Rockefeller up to 93μg/L for Marilia field derived population. In addition, a semi-field trial was performed to evaluate spinosad (NatularTM DT) initial efficacy and persistence toward four field-derived lineages and the Rockefeller lineage, used as an internal control. Spinosad was tested at 0.5mg active ingredient/L in 200L capacity water tanks. Mortality was recorded each 24 hours after exposition and tanks were further recolonized once per week with mortality being recorded daily for eight weeks. Spinosad provided a level equal or superior to 80% mortality during a seven to eight week evaluation period. The assessed populations did not present cross-resistance between spinosad and temephos in laboratory conditions. It demonstrates that spinosad may be a promising larvicide for the control of Ae. aegypti, especially for populations in which resistance to temephos has been detected. PMID:28301568

  4. Aedes cadherin mediates the in vivo toxicity of the Cry11Aa toxin to Aedes aegypti

    PubMed Central

    Aimanova, Karlygash G.; Gill, Sarjeet S.

    2014-01-01

    Cadherin plays an important role in the toxicity of Bacillus thuringiensis Cry proteins. We previously cloned a full-length cadherin from Aedes aegypti larvae and reported this protein binds Cry11Aa toxin from B. thuringiensis subsp. israelensis with high affinity, ≈ 16.7 nM. Based on these results, we investigated if Aedes cadherin is involved in the in vivo toxicity of Cry11Aa toxin to Ae. aegypti. We established a mosquito cell line stably expressing the full-length Aedes cadherin and transgenic mosquitoes with silenced Aedes cadherin expression. Cells expressing the Aedes cadherin showed increased sensitivity to Cry11Aa toxin. Cry11Aa toxin at 400 nM killed approximately 37% of the cells in 3 h. Otherwise, transgenic mosquitoes with silenced Aedes cadherin expression showed increased tolerance to Cry11Aa toxin. Furthermore, cells expressing Aedes cadherin triggered Cry11Aa oligomerization. These results show the Aedes cadherin plays a pivotal role in Cry11Aa toxicity to Ae. aegypti larvae by mediating Cry11Aa oligomerization. However, since high toxicity was not obtained in cadherin-expressing cells, an additional receptor may be needed for manifestation of full toxicity. Moreover, cells expressing Aedes cadherin were sensitive to Cry4Aa and Cry11Ba but not Cry4Ba. However transgenic mosquitoes with silenced Aedes cadherin expression showed no tolerance to Cry4Aa, Cry4Ba, and Cry11Ba toxins. These results suggest that while Aedes cadherin may mediate Cry4Aa and Cry11Ba toxicity, this cadherin but is not the main receptor of Cry4Aa, Cry4Ba and Cry11Ba toxin in Ae. aegypti. PMID:25064814

  5. Adult survivorship of the dengue mosquito Aedes aegypti varies seasonally in central Vietnam.

    PubMed

    Hugo, Leon E; Jeffery, Jason A L; Trewin, Brendan J; Wockner, Leesa F; Nguyen, Thi Yen; Nguyen, Hoang Le; Nghia, Le Trung; Hine, Emma; Ryan, Peter A; Kay, Brian H

    2014-02-01

    The survival characteristics of the mosquito Aedes aegypti affect transmission rates of dengue because transmission requires infected mosquitoes to survive long enough for the virus to infect the salivary glands. Mosquito survival is assumed to be high in tropical, dengue endemic, countries like Vietnam. However, the survival rates of wild populations of mosquitoes are seldom measured due the difficulty of predicting mosquito age. Hon Mieu Island in central Vietnam is the site of a pilot release of Ae. aegypti infected with a strain of Wolbachia pipientis bacteria (wMelPop) that induces virus interference and mosquito life-shortening. We used the most accurate mosquito age grading approach, transcriptional profiling, to establish the survival patterns of the mosquito population from the population age structure. Furthermore, estimations were validated on mosquitoes released into a large semi-field environment consisting of an enclosed house, garden and yard to incorporate natural environmental variability. Mosquito survival was highest during the dry/cool (January-April) and dry/hot (May-August) seasons, when 92 and 64% of Hon Mieu mosquitoes had survived to an age that they were able to transmit dengue (12 d), respectively. This was reduced to 29% during the wet/cool season from September to December. The presence of Ae. aegypti older than 12 d during each season is likely to facilitate the observed continuity of dengue transmission in the region. We provide season specific Ae. aegypti survival models for improved dengue epidemiology and evaluation of mosquito control strategies that aim to reduce mosquito survival to break the dengue transmission cycle.

  6. Weather Variability Associated with Aedes (Stegomyia) aegypti (Dengue Vector) Oviposition Dynamics in Northwestern Argentina

    PubMed Central

    Estallo, Elizabet L.; Ludueña-Almeida, Francisco F.; Introini, María V.; Zaidenberg, Mario; Almirón, Walter R.

    2015-01-01

    This study aims to develop a forecasting model by assessing the weather variability associated with seasonal fluctuation of Aedes aegypti oviposition dynamic at a city level in Orán, in northwestern Argentina. Oviposition dynamics were assessed by weekly monitoring of 90 ovitraps in the urban area during 2005-2007. Correlations were performed between the number of eggs collected weekly and weather variables (rainfall, photoperiod, vapor pressure of water, temperature, and relative humidity) with and without time lags (1 to 6 weeks). A stepwise multiple linear regression analysis was performed with the set of meteorological variables from the first year of study with the variables in the time lags that best correlated with the oviposition. Model validation was conducted using the data from the second year of study (October 2006- 2007). Minimum temperature and rainfall were the most important variables. No eggs were found at temperatures below 10°C. The most significant time lags were 3 weeks for minimum temperature and rains, 3 weeks for water vapor pressure, and 6 weeks for maximum temperature. Aedes aegypti could be expected in Orán three weeks after rains with adequate min temperatures. The best-fit forecasting model for the combined meteorological variables explained 70 % of the variance (adj. R2). The correlation between Ae. aegypti oviposition observed and estimated by the forecasting model resulted in rs = 0.80 (P < 0.05). The forecasting model developed would allow prediction of increases and decreases in the Ae. aegypti oviposition activity based on meteorological data for Orán city and, according to the meteorological variables, vector activity can be predicted three or four weeks in advance. PMID:25993415

  7. Mathematical model to assess the control of Aedes aegypti mosquitoes by the sterile insect technique.

    PubMed

    Esteva, Lourdes; Mo Yang, Hyun

    2005-12-01

    We propose a mathematical model to assess the effects of irradiated (or transgenic) male insects introduction in a previously infested region. The release of sterile male insects aims to displace gradually the natural (wild) insect from the habitat. We discuss the suitability of this release technique when applied to peri-domestically adapted Aedes aegypti mosquitoes which are transmissors of Yellow Fever and Dengue disease.

  8. Oviposition Site Selection by the Dengue Vector Aedes aegypti and Its Implications for Dengue Control

    PubMed Central

    Wong, Jacklyn; Stoddard, Steven T.; Astete, Helvio; Morrison, Amy C.; Scott, Thomas W.

    2011-01-01

    Background Because no dengue vaccine or antiviral therapy is commercially available, controlling the primary mosquito vector, Aedes aegypti, is currently the only means to prevent dengue outbreaks. Traditional models of Ae. aegypti assume that population dynamics are regulated by density-dependent larval competition for food and little affected by oviposition behavior. Due to direct impacts on offspring survival and development, however, mosquito choice in oviposition site can have important consequences for population regulation that should be taken into account when designing vector control programs. Methodology/Principal Findings We examined oviposition patterns by Ae. aegypti among 591 naturally occurring containers and a set of experimental containers in Iquitos, Peru. Using larval starvation bioassays as an indirect measure of container food content, we assessed whether females select containers with the most food for their offspring. Our data indicate that choice of egg-laying site is influenced by conspecific larvae and pupae, container fill method, container size, lid, and sun exposure. Although larval food positively influenced oviposition, our results did not support the hypothesis that females act primarily to maximize food for larvae. Females were most strongly attracted to sites containing immature conspecifics, even when potential competitors for their progeny were present in abundance. Conclusion/Significance Due to strong conspecific attraction, egg-laying behavior may contribute more to regulating Ae. aegypti populations than previously thought. If highly infested containers are targeted for removal or larvicide application, females that would have preferentially oviposited in those sites may instead distribute their eggs among other suitable, previously unoccupied containers. Strategies that kill mosquitoes late in their development (i.e., insect growth regulators that kill pupae rather than larvae) will enhance vector control by creating

  9. Global temperature constraints on Aedes aegypti and Ae. albopictus persistence and competence for dengue virus transmission

    PubMed Central

    2014-01-01

    Background Dengue is a disease that has undergone significant expansion over the past hundred years. Understanding what factors limit the distribution of transmission can be used to predict current and future limits to further dengue expansion. While not the only factor, temperature plays an important role in defining these limits. Previous attempts to analyse the effect of temperature on the geographic distribution of dengue have not considered its dynamic intra-annual and diurnal change and its cumulative effects on mosquito and virus populations. Methods Here we expand an existing modelling framework with new temperature-based relationships to model an index proportional to the basic reproductive number of the dengue virus. This model framework is combined with high spatial and temporal resolution global temperature data to model the effects of temperature on Aedes aegypti and Ae. albopictus persistence and competence for dengue virus transmission. Results Our model predicted areas where temperature is not expected to permit transmission and/or Aedes persistence throughout the year. By reanalysing existing experimental data our analysis indicates that Ae. albopictus, often considered a minor vector of dengue, has comparable rates of virus dissemination to its primary vector, Ae. aegypti, and when the longer lifespan of Ae. albopictus is considered its competence for dengue virus transmission far exceeds that of Ae. aegypti. Conclusions These results can be used to analyse the effects of temperature and other contributing factors on the expansion of dengue or its Aedes vectors. Our finding that Ae. albopictus has a greater capacity for dengue transmission than Ae. aegypti is contrary to current explanations for the comparative rarity of dengue transmission in established Ae. albopictus populations. This suggests that the limited capacity of Ae. albopictus to transmit DENV is more dependent on its ecology than vector competence. The recommendations, which we

  10. [Presence of Aedes aegypti in Bromeliaceae and plant breeding places in Brazil].

    PubMed

    Cunha, Sergio P; Alves, João R Carreira; Lima, Milton M; Duarte, Jair R; de Barros, Luiz C V; da Silva, José L; Gammaro, Angelo T; Monteiro Filho, Orlando de S; Wanzeler, Amauri R

    2002-04-01

    The frequency of Bromeliaceae and other plant breeding places where Aedes aegypti can be found is reported during two consecutive operational cycles (focal treatment) in the city of Rio de Janeiro. These cycles took place from November 12 2000 to March 9 2001 and from March 12 2001 to June 15 2001. This study concentrates on the epidemiological implications resulting from the growing use of these plants as decorative living objects.

  11. Aedes cadherin mediates the in vivo toxicity of the Cry11Aa toxin to Aedes aegypti.

    PubMed

    Lee, Su-Bum; Chen, Jianwu; Aimanova, Karlygash G; Gill, Sarjeet S

    2015-06-01

    Cadherin plays an important role in the toxicity of Bacillus thuringiensis Cry proteins. We previously cloned a full-length cadherin from Aedes aegypti larvae and reported this protein binds Cry11Aa toxin from B. thuringiensis subsp. israelensis with high affinity, ≈16.7nM. Based on these results, we investigated if Aedes cadherin is involved in the in vivo toxicity of Cry11Aa toxin to Ae. aegypti. We established a mosquito cell line stably expressing the full-length Aedes cadherin and transgenic mosquitoes with silenced Aedes cadherin expression. Cells expressing the Aedes cadherin showed increased sensitivity to Cry11Aa toxin. Cry11Aa toxin at 400nM killed approximately 37% of the cells in 3h. Otherwise, transgenic mosquitoes with silenced Aedes cadherin expression showed increased tolerance to Cry11Aa toxin. Furthermore, cells expressing Aedes cadherin triggered Cry11Aa oligomerization. These results show the Aedes cadherin plays a pivotal role in Cry11Aa toxicity to Ae. aegypti larvae by mediating Cry11Aa oligomerization. However, since high toxicity was not obtained in cadherin-expressing cells, an additional receptor may be needed for manifestation of full toxicity. Moreover, cells expressing Aedes cadherin were sensitive to Cry4Aa and Cry11Ba, but not Cry4Ba. However transgenic mosquitoes with silenced Aedes cadherin expression showed no tolerance to Cry4Aa, Cry4Ba, and Cry11Ba toxins. These results suggest that while Aedes cadherin may mediate Cry4Aa and Cry11Ba toxicity, this cadherin but is not the main receptor of Cry4Aa, Cry4Ba and Cry11Ba toxin in Ae. aegypti.

  12. Larvicidal activity against Aedes aegypti of Foeniculum vulgare essential oils from Portugal and Cape Verde.

    PubMed

    Rocha, Diara Kady; Matosc, Olivia; Novoa, Maria Teresa; Figueiredo, Ana Cristina; Delgado, Manuel; Moiteiro, Cristina

    2015-04-01

    Dengue is a potentially fatal mosquito-borne infection with 50 million cases per year and 2.5 billion people vulnerable to the disease. This major public health problem has recurrent epidemics in Latin America and occurred recently in Cape Verde and Madeira Island. The lack of anti-viral treatment or vaccine makes the control of mosquito vectors a high option to prevent virus transmission. Essential oil (EO) constituents can affect insect's behaviour, being potentially effective in pest control. The present study evaluated the potential use of Foenicultm vulgare (fennel) EO in the control of the dengue vector Aedes aegypti. EOs isolated from fennel aerial parts collected in Cape Verde and from a commercial fennel EO of Portugal were analysed by NMR, GC and GC-MS. trans-Anethole (32 and 30%, respectively), limonene (28 and 18%, respectively) and fenchone (10% in both cases) were the main compounds identified in the EOs isolated from fennel from Cape Verde and Portugal, respectively. The larvicidal activity of the EOs and its major constituents were evaluated, using WHO procedures, against third instar larvae ofAe. aegypti for 24 h. Pure compounds, such as limonene isomers, were also assayed. The lethal concentrations LC50, C90 and LC99 were determined by probit analysis using mortality rates of bioassays. A 99% mortality of Ae. aegypti larvae was estimated at 37.1 and 52.4 µL L-1 of fennel EOs from Cape Verde and Portugal, respectively. Bioassays showed that fennel EOs from both countries displayed strong larvicidal effect against Ae. aegypti, the Cape Verde EO being as active as one of its major constituents, (-)-limonene.

  13. The queenslandensis and the type Form of the Dengue Fever Mosquito (Aedes aegypti L.) Are Genomically Indistinguishable

    PubMed Central

    Filipović, Igor; Callahan, Ashley G.; Stanford, Darren; Chan, Abigail; Lam-Phua, Sai Gek; Tan, Cheong Huat; Hoffmann, Ary Anthony

    2016-01-01

    Background The mosquito Aedes aegypti (L.) is a major vector of viral diseases like dengue fever, Zika and chikungunya. Aedes aegypti exhibits high morphological and behavioral variation, some of which is thought to be of epidemiological significance. Globally distributed domestic Ae. aegypti have often been grouped into (i) the very pale variety queenslandensis and (ii) the type form. Because the two color forms co-occur across most of their range, there is interest in understanding how freely they interbreed. This knowledge is particularly important for control strategies that rely on mating compatibilities between the release and target mosquitoes, such as Wolbachia releases and SIT. To address this question, we analyzed nuclear and mitochondrial genome-wide variation in the co-occurring pale and type Ae. aegypti from northern Queensland (Australia) and Singapore. Methods/Findings We typed 74 individuals at a 1170 bp-long mitochondrial sequence and at 16,569 nuclear SNPs using a customized double-digest RAD sequencing. 11/29 genotyped individuals from Singapore and 11/45 from Queensland were identified as var. queenslandensis based on the diagnostic scaling patterns. We found 24 different mitochondrial haplotypes, seven of which were shared between the two forms. Multivariate genetic clustering based on nuclear SNPs corresponded to individuals’ geographic location, not their color. Several family groups consisted of both forms and three queenslandensis individuals were Wolbachia infected, indicating previous breeding with the type form which has been used to introduce Wolbachia into Ae. aegypti populations. Conclusion Aedes aegypti queenslandensis are genomically indistinguishable from the type form, which points to these forms freely interbreeding at least in Australia and Singapore. Based on our findings, it is unlikely that the presence of very pale Ae. aegypti will affect the success of Aedes control programs based on Wolbachia-infected, sterile or RIDL

  14. Use of the CDC Autocidal Gravid Ovitrap to Control and Prevent Outbreaks of Aedes aegypti (Diptera: Culicidae)

    PubMed Central

    Barrera, Roberto; Amador, Manuel; Acevedo, Veronica; Caban, Belkis; Felix, Gilberto; Mackay, Andrew J.

    2015-01-01

    Populations of Aedes aegypti (L.) can be managed through reductions in adult mosquito survival, number of offspring produced, or both. Direct adult mortality can be caused by the use of space sprays or residual insecticides to mosquito resting sites, and with a variety of residual insecticide-impregnated surfaces that are being tested, such as curtains, covers for water-storage vessels, bednets, and ovitraps. The fertility of Ae. aegypti populations can be reduced by the use of autocidal oviposition cups that prevent the development of mosquitoes inside the trap by mechanical means or larvicides, as well as by releasing sterile, transgenic, and para-transgenic mosquitoes. Survival and fertility can be simultaneously reduced by capturing gravid female Ae. aegypti with sticky gravid traps. We tested the effectiveness of the novel Centers for Disease Control and Prevention autocidal gravid ovitrap (CDC-AGO trap) to control natural populations of Ae. aegypti under field conditions in two isolated urban areas (reference vs. intervention areas) in southern Puerto Rico for 1 yr. There were significant reductions in the captures of female Ae. aegypti (53–70%) in the intervention area. The presence of three to four AGO control traps per home in 81% of the houses prevented outbreaks of Ae. aegypti, which would be expected after rains. Mosquito captures in BG-Sentinel and AGO traps were significantly and positively correlated, showing that AGO traps are useful and inexpensive mosquito surveillance devices. The use of AGO traps to manage Ae. aegypti populations is compatible with other control means such as source reduction, larviciding, adulticiding, sterile insect techniques, induced cytoplasmic incompatibility, and dominant lethal gene systems. PMID:24605464

  15. The microbiome composition of Aedes aegypti is not critical for Wolbachia-mediated inhibition of dengue virus

    PubMed Central

    Audsley, Michelle D.; Ye, Yixin H.

    2017-01-01

    Background Dengue virus (DENV) is primarily vectored by the mosquito Aedes aegypti, and is estimated to cause 390 million human infections annually. A novel method for DENV control involves stable transinfection of Ae. aegypti with the common insect endosymbiont Wolbachia, which mediates an antiviral effect. However, the mechanism by which Wolbachia reduces the susceptibility of Ae. aegypti to DENV is not fully understood. In this study we assessed the potential of resident microbiota, which can play important roles in insect physiology and immune responses, to affect Wolbachia-mediated DENV blocking. Methodology/Findings The microbiome of Ae. aegypti stably infected with Wolbachia strain wMel was compared to that of Ae. aegypti without Wolbachia, using 16s rDNA profiling. Our results indicate that although Wolbachia affected the relative abundance of several genera, the microbiome of both the Wolbachia-infected and uninfected mosquitoes was dominated by Elizabethkingia and unclassified Enterobacteriaceae. To assess the potential of the resident microbiota to affect the Wolbachia-mediated antiviral effect, we used antibiotic treatment before infection with DENV by blood-meal. In spite of a significant shift in the microbiome composition in response to the antibiotics, we detected no effect of antibiotic treatment on DENV infection rates, or on the DENV load of infected mosquitoes. Conclusions/Significance Our findings indicate that stable infection with Wolbachia strain wMel produces few effects on the microbiome of laboratory-reared Ae. aegypti. Moreover, our findings suggest that the microbiome can be significantly altered without affecting the fundamental DENV blocking phenotype in these mosquitoes. Since Ae. aegypti are likely to encounter diverse microbiota in the field, this is a particularly important result in the context of using Wolbachia as a method for DENV control. PMID:28267749

  16. Use of the CDC autocidal gravid ovitrap to control and prevent outbreaks of Aedes aegypti (Diptera: Culicidae).

    PubMed

    Barrera, Roberto; Amador, Manuel; Acevedo, Veronica; Caban, Belkis; Felix, Gilberto; Mackay, Andrew J

    2014-01-01

    Populations ofAedes aegypti (L.) can be managed through reductions in adult mosquito survival, number of offspring produced, or both. Direct adult mortality can be caused by the use of space sprays or residual insecticides to mosquito resting sites, and with a variety of residual insecticide-impregnated surfaces that are being tested, such as curtains, covers for water-storage vessels, bednets, and ovitraps. The fertility ofAe. aegypti populations can be reduced by the use of autocidal oviposition cups that prevent the development of mosquitoes inside the trap by mechanical means or larvicides, as well as by releasing sterile, transgenic, and para-transgenic mosquitoes. Survival and fertility can be simultaneously reduced by capturing gravid female Ae. aegypti with sticky gravid traps. We tested the effectiveness of the novel Centers for Disease Control and Prevention autocidal gravid ovitrap (CDC-AGO trap) to control natural populations ofAe. aegypti under field conditions in two isolated urban areas (reference vs. intervention areas) in southern Puerto Rico for 1 yr. There were significant reductions in the captures of female Ae. aegypti (53-70%) in the intervention area The presence of three to four AGO control traps per home in 81% of the houses prevented outbreaks of Ae. aegypti, which would be expected after rains. Mosquito captures in BG-Sentinel and AGO traps were significantly and positively correlated, showing that AGO traps are useful and inexpensive mosquito surveillance devices. The use of AGO traps to manage Ae. aegypti populations is compatible with other control means such as source reduction, larviciding, adulticiding, sterile insect techniques, induced cytoplasmic incompatibility, and dominant lethal gene systems.

  17. Temporal genetic structure of major dengue vector Aedes aegypti from Manaus, Amazonas, Brazil.

    PubMed

    Mendonça, Barbara Alessandra Alves; de Sousa, Adna Cristina Barbosa; de Souza, Anete Pereira; Scarpassa, Vera Margarete

    2014-06-01

    In recent years, high levels of Aedes aegypti infestation and several dengue outbreaks with fatal outcome cases have been reported in Manaus, State of Amazonas, Brazil. This situation made it important to understand the genetic structure and gene flow patterns among the populations of this vector in Manaus, vital pieces of information for their management and development of new control strategies. In this study, we used nine microsatellite loci to examine the effect of seasonality on the genetic structure and gene flow patterns in Ae. aegypti populations from four urban neighborhoods of Manaus, collected during the two main rainy and dry seasons. All loci were polymorphic in the eight samples from the two seasons, with a total of 41 alleles. The genetic structure analyses of the samples from the rainy season revealed genetic homogeneity and extensive gene flow, a result consistent with the abundance of breeding sites for this vector. However, the samples from the dry season were significantly structured, due to a reduction of Ne in two (Praça 14 de Janeiro and Cidade Nova) of the four samples analyzed, and this was the primary factor influencing structure during the dry season. Genetic bottleneck analyses suggested that the Ae. aegypti populations from Manaus are being maintained continuously throughout the year, with seasonal reduction rather than severe bottleneck or extinction, corroborating previous reports. These findings are of extremely great importance for designing new dengue control strategies in Manaus.

  18. Determination of dengue virus serotypes in individual Aedes aegypti mosquitoes in Colombia.

    PubMed

    Romero-Vivas, C M; Leake, C J; Falconar, A K

    1998-07-01

    Adult Aedes aegypti mosquitoes were collected in Puerto Triunfo, central Colombia, where dengue is endemic, during a six month period. Viral infection within the head of each individual mosquito was identified by an immunofluorescent assay (IFA) using a flavivirus-specific monoclonal antibody. The dengue virus serotype, present in each flavivirus-positive specimen, was then determined in portions of the remaining thorax using IFAs with serotype-specific monoclonal antibodies. Among 2065 female Aedes aegypti collected and tested, twenty-four flavivirus-positive individuals were found (minimum infection rate 11.6%), three identified as dengue type-1 and twenty-one as dengue type-2 virus. This was consistent with the isolation of only these two serotypes of dengue virus from dengue fever patients within this town. No vertical transmission of dengue virus could be detected in 1552 male Aedes aegypti collected. This method is inexpensive, simple, rapid to perform and suitable for use in developing countries to identify and distinguish different serotypes of dengue virus in their vectors during eco-epidemiological investigations.

  19. The use of Aedes aegypti larvae attractants to enhance the effectiveness of larvicides.

    PubMed

    Gonzalez, Paula V; Harburguer, Laura; González-Audino, Paola A; Masuh, Héctor M

    2016-06-01

    Aedes aegypti (L.) is an important dengue, chikungunya, and yellow fever vector. Immature stages of this species inhabit human-made containers placed in residential landscapes, and the application of larvicides inside containers that cannot be eliminated is still considered a priority in control programs. Larvicidal efficacy is influenced by several factors, including the formulation used, the water quality, and the susceptibility of larvae, among others. If an attractant can be incorporated into a slow-release larvicide formulation, it will be feasible to direct the larvae into the source of insecticide and thereby improving its efficacy. We studied the influence of 1-octen-3ol and 3-methylphenol on the rate of Ae. aegypti larvae mortality using the larvicides Bacillus thuringiensis var. israelensis (Bti), temephos, and spinosad. These chemicals were combined with the larvicides mixed with agar during the bioassays. Mortality was registered every 10 min, and a lethal time 50 (LT50) was calculated. The inclusion of the Ae. aegypti larvae attractants with the larvicides into a solid agar matrix improved their efficiency obtaining a strong and marked reduction in the LT50 compared with the use of larvicides alone.

  20. Metabolic fate of [14C]-labeled meal protein amino acids in Aedes aegypti mosquitoes.

    PubMed

    Zhou, Guoli; Flowers, Matthew; Friedrich, Kenneth; Horton, James; Pennington, James; Wells, Michael A

    2004-04-01

    We developed a method to follow the metabolic fate of [(14)C]-labeled Euglena gracilis protein amino acids in Aedes aegypti mosquitoes under three different adult nutritional regimes. Quantitative analysis of blood meal protein amino acid metabolism showed that most of the carbon of the amino acids was either oxidized to CO(2) or excreted as waste. Under the three different adult nutritional regimes, no significant differences in the metabolism of amino acids were found, which indicated that the female A. aegypti mosquitoes possess a substantial capacity of maintaining metabolic homeostasis during a gonotrophic cycle. The amount of maternal glycogen and lipid after egg laying were significantly lower in the mosquitoes that underwent a partial starvation before a blood meal and/or starvation after the blood meal. The content of egg lipid or protein or the number of eggs laid did not show a significant difference among the three different regimes, which indicates that stable fecundity of A. aegypti under the partial starvation before a blood meal and/or starvation after the blood meal seemed to result from a trade-off between current fecundity and future survival after the eggs laid. The methods described in this paper can be applied to a wide range of questions about the effects of environmental conditions on the utilization of blood meal amino acids.

  1. Reduced oviposition of Aedes aegypti gravid females in domestic containers with predatory fish.

    PubMed

    Pamplona, Luciano de Góes Cavalcanti; Alencar, Carlos H; Lima, José Wellington O; Heukelbach, Jörg

    2009-11-01

    The presence of pathogens or predators in water may alter oviposition behaviour of gravid female Aedes aegypti mosquitoes. We evaluated the oviposition behaviour of A. aegypti in recipients containing larvivorous fish (Betta splendens and Poecilia reticulata). In four breeders, fish specimens were placed in 15 l of dechlorined water. Four control breeders only contained dechlorined water. Breeders with eucatex ovitraps and approximately 100 male and female mosquitoes were placed in wire netting cages. During a period of 7 weeks, eggs on the ovitraps were counted weekly. The median number of eggs laid in recipients with B. splendens (32.5/week) was lower than in those with P. reticulata (200.5/week) and the control group (186.5/week; P < 0.0001). The oviposition activity index (OAI) for P. reticulata did not show any considerable difference between posture in deposits with and without fish (-0005). Deposits with B. splendens showed a lower position than those used as controls (-0627). We conclude that B. splendens can be used to effectively prevent gravid A. aegypti females from laying eggs in large water containers.

  2. Mobility properties of the Hermes transposable element in transgenic lines of Aedes aegypti

    PubMed Central

    Smith, Ryan C.

    2010-01-01

    The Hermes transposable element has been used to genetically transform a wide range of insect species, including the mosquito, Aedes aegypti, a vector of several important human pathogens. Hermes integrations into the mosquito germline are characterized by the non-canonical integration of the transposon and flanking plasmid and, once integrated, Hermes is stable in the presence of its transposase. In an effort to improve the post-integration mobility of Hermes in the germline of Ae. aegypti, a transgenic helper Mos1 construct expressing Hermes transposase under the control of a testis-specific promoter was crossed to a separate transgenic strain containing a target Hermes transposon. In less than 1% of the approximately 1,500 progeny from jumpstarter lines analyzed, evidence of putative Hermes germline remobilizations were detected. These recovered transposition events occur through an aberrant mechanism and provide insight into the non-canonical cut-and-paste transposition of Hermes in the germ line of Ae. aegypti. PMID:20596755

  3. Engineering RNA interference-based resistance to dengue virus type 2 in genetically modified Aedes aegypti.

    PubMed

    Franz, Alexander W E; Sanchez-Vargas, Irma; Adelman, Zach N; Blair, Carol D; Beaty, Barry J; James, Anthony A; Olson, Ken E

    2006-03-14

    Mosquitoes (Aedes aegypti) were genetically modified to exhibit impaired vector competence for dengue type 2 viruses (DENV-2). We exploited the natural antiviral RNA interference (RNAi) pathway in the mosquito midgut by constructing an effector gene that expresses an inverted-repeat (IR) RNA derived from the premembrane protein coding region of the DENV-2 RNA genome. The A. aegypti carboxypeptidase A promoter was used to express the IR RNA in midgut epithelial cells after ingestion of a bloodmeal. The promoter and effector gene were inserted into the genome of a white-eye Puerto Rico Rexville D (Higgs' white eye) strain by using the nonautonomous mariner MosI transformation system. A transgenic family, Carb77, expressed IR RNA in the midgut after a bloodmeal. Carb77 mosquitoes ingesting an artificial bloodmeal containing DENV-2 exhibited marked reduction of viral envelope antigen in midguts and salivary glands after infection. DENV-2 titration of individual mosquitoes showed that most Carb77 mosquitoes poorly supported virus replication. Transmission in vitro of virus from the Carb77 line was significantly diminished when compared to control mosquitoes. The presence of DENV-2-derived siRNAs in RNA extracts from midguts of Carb77 and the loss of the resistance phenotype when the RNAi pathway was interrupted proved that DENV-2 resistance was caused by a RNAi response. Engineering of transgenic A. aegypti that show a high level of resistance against DENV-2 provides a powerful tool for developing population replacement strategies to control transmission of dengue viruses.

  4. Relish2 mediates bursicon homodimer-induced prophylactic immunity in the mosquito Aedes aegypti.

    PubMed

    Zhang, Hongwei; Dong, Shengzhang; Chen, Xi; Stanley, David; Beerntsen, Brenda; Feng, Qili; Song, Qisheng

    2017-02-22

    Bursicon is a neuropeptide hormone consisting of two cystine-knot proteins (burs α and burs β), responsible for cuticle tanning and other developmental processes in insects. Recent studies show that each bursicon subunit forms homodimers that induce prophylactic immunity in Drosophila melanogaster. Here, we investigated the hypothesis that bursicon homodimers act in prophylactic immunity in insects, and possibly arthropods, generally, using the mosquito, Aedes aegypti. We found that burs α and burs β are expressed in larvae, pupae and newly emerged adults. Treating newly emerged Ae. aegypti and D. melanogaster adults with recombinant bursicon (r-bursicon) heterodimer led to cuticle tanning in both species. Treating larvae and adults with r-bursicon homodimers led to up-regulation of five anti-microbial peptide (AMP) genes, noting the possibility that bursicon heterodimers also lead to up-regulation of these genes can not been excluded. The induced AMPs effectively suppressed the growth of bacteria in vitro. RNAi knock-down of the transcriptional factor Relish2 abolished the influence of r-bursicon homodimers on AMP production. We infer the bursicon homodimers induce expression of AMP genes via Relish2 in Ae. aegypti, as prophylactic immunity to protect mosquitoes during the vulnerable stages of each molt.

  5. Identification and initial characterization of matrix metalloproteinases in the yellow fever mosquito, Aedes aegypti.

    PubMed

    Kantor, A M; Dong, S; Held, N L; Ishimwe, E; Passarelli, A L; Clem, R J; Franz, A W E

    2017-02-01

    Aedes aegypti is a major vector for arboviruses such as dengue, chikungunya and Zika viruses. During acquisition of a viremic bloodmeal, an arbovirus infects mosquito midgut cells before disseminating to secondary tissues, including the salivary glands. Once virus is released into the salivary ducts it can be transmitted to another vertebrate host. The midgut is surrounded by a basal lamina (BL) in the extracellular matrix, consisting of a proteinaceous mesh composed of collagen IV and laminin. BL pore size exclusion limit prevents virions from passing through. Thus, the BL probably requires remodelling via enzymatic activity to enable efficient virus dissemination. Matrix metalloproteinases (MMPs) are extracellular endopeptidases that are involved in remodelling of the extracellular matrix. Here, we describe and characterize the nine Ae. aegypti encoded MMPs, AeMMPs 1-9, which share common features with other invertebrate and vertebrate MMPs. Expression profiling in Ae. aegypti revealed that Aemmp4 and Aemmp6 were upregulated during metamorphosis, whereas expression of Aemmp1 and Aemmp2 increased during bloodmeal digestion. Aemmp1 expression was also upregulated in the presence of a bloodmeal containing chikungunya virus. Using polyclonal antibodies, AeMMP1 and AeMMP2 were specifically detected in tissues associated with the mosquito midgut.

  6. Thermal sensitivity of Aedes aegypti from Australia: empirical data and prediction of effects on distribution.

    PubMed

    Richardson, Kelly; Hoffmann, Ary A; Johnson, Petrina; Ritchie, Scott; Kearney, Michael R

    2011-07-01

    An understanding of physiological sensitivity to temperature and its variability is important for predicting habitat suitability for disease vectors under different climatic regimes. In this study, we characterized the thermal sensitivity of larval developmental rates and survival in several Australian mainland populations of the dengue virus vector Aedes aegypti. Males developed more rapidly than females, but there were no differences among populations for development time or survival despite previously demonstrated genetic differentiation for neutral markers. Optimal development and survival temperatures were 37 degrees C and 25 degrees C, respectively. The values for maximal development and survival were similar to standard functions used in the container inhabiting simulation (CIMSIM) model for predicting population dynamics ofAe. aegypti populations, but CIMSIM assumed a lower optimal temperature. Heat stress experiments indicated that larvae could withstand water temperatures up to 44 degrees C regardless of the rate at which temperature was increased. Results from development time measured under constant temperatures could predict development time under fluctuating conditions, whereas CIMSIM predicted faster rates of development. This difference acts to reduce the predicted potential number of generations of Ae. aegypti per year in Australia, although it does not influence its predicted distribution, which depends critically on the nature of the aquatic breeding sites.

  7. Genetic analysis of abnormal male sexual development in Aedes aegypti and Ae. mascarensis backcross progeny.

    PubMed

    Hilburn, L R; Rai, K S

    1982-01-01

    When male hybrids of Aedes aegypti females and A. mascarensis males were backcrossed to A. aegypti females, 32.8 percent of the male progeny exhibited abnormal sexual development, including failure of the terminalia to rotate, a split sternite of the eighth abdominal segment with partially duplicated telomeres, or feminization that gives rise to sterile intersexes. Observations made on three morphological marker loci and five isozyme loci with characteristic electromorphs in the two parental species suggested that when the sex-determining M locus is derived from A. mascarensis and the chromosome regions including s, LDH, and lDH2 on chromosome 2 and blt and 6PGD on chromosome 3 are homozygous for genes from A. aegypti, the frequency of abnormal sexual development is increased. An even greater percentage of males suffer aberrant development if recombination also occurs between the M and re locus of chromosome 1. The data suggest that genes on chromosome 2 control normal development of the male terminalia, genes on chromosome 3 control sexual differentiation, and the entire process is controlled by genes on chromosome 1 that are linked to, but not identical with, the M locus.

  8. Reinvestigation of an endogenous meiotic drive system in the mosquito, Aedes aegypti (Diptera: Culicidae).

    PubMed

    Mori, Akio; Chadee, Dave D; Graham, Douglas H; Severson, David W

    2004-11-01

    We have initiated efforts to determine the molecular basis for the M(D) meiotic drive system in the mosquito, Aedes aegypti. The effect of the M(D) gene is a highly male-biased sex ratio, but varies depending on the frequency and sensitivity of a susceptible responder m(s) allele. The M(D) system has potential as a mechanism for driving trangenes for pathogen resistance into natural Ae. aegypti populations. Because all previously existing laboratory strains carrying the M(D) gene have been lost, we have selected for a new strain, T37, that carries a strong driver. Matings between T37 males and drive-susceptible m(s) females result in progeny with highly biased sex ratios, wherein only approximately 14.7% females are produced. We discuss the potential for identifying M(D) candidate genes based on comparisons with the well-described Drosophila melanogaster segregation distorter (SD) meiotic drive system and considerations for release of transgenic Ae. aegypti into natural populations where M(D) and insensitive m3 alleles are likely segregating.

  9. Oral toxicity of Photorhabdus luminescens and Xenorhabdus nematophila (Enterobacteriaceae) against Aedes aegypti (Diptera: Culicidae).

    PubMed

    da Silva, Onilda Santos; Prado, Geronimo Rodrigues; da Silva, João Luiz Rosa; Silva, Carlos Eugenio; da Costa, Marisa; Heermann, Ralf

    2013-08-01

    Dengue fever is an important vector-borne disease, mainly transmitted by Aedes aegypti. To date, there are no vaccines or effective drugs available against this arboviral disease. As mosquito control is practically the only method available to control dengue fever, alternative and cost-effective pest control strategies need to be explored. The gram-negative enteric bacteria Xenorhabdus and Photorhabdus are symbiotically associated with nematode parasites, which themselves are highly pathogenic for insect larvae. Here, we evaluate the oral toxicity of these entomopathogenic bacteria in A. aegypti larvae. The susceptibility of larvae (third late or fourth early instars) was assessed by exposing them to suspensions containing Photorhabdus luminescens or Xenorhabdus nematophila, respectively. Two diet treatments were tested with larvae fed on pet food and unfed larvae. After 24 h, larvae began to die when exposed to the bacteria. Exposure to P. luminescens killed 73% of the fed and 83% of the unfed larvae, respectively. In comparison, X. nematophila was less pathogenic, killing 52% of the larvae in the fed and 42% in the unfed treatment. Remarkably, cannibalism was observed in all bioassays after exposing larvae to either of the bacterial species. To our knowledge, this is the first report demonstrating the efficiency of these entomopathogenic bacteria for oral A. aegypti killing. Our results provide a promising basis for using these bacteria as bioinsecticides for mosquito control in the future.

  10. Differential transcription profiles in Aedes aegypti detoxification genes following temephos selection

    PubMed Central

    Saavedra-Rodriguez, Karla; Strode, Clare; Flores, Adriana E.; Garcia-Luna, Selene; Reyes-Solis, Guadalupe; Ranson, Hilary; Hemingway, Janet; Black, William C.

    2014-01-01

    The mosquito Aedes aegypti is the main vector of Dengue and Yellow Fever flaviviruses. The organophosphate insecticide temephos is a larvicide that is used globally to control Ae. aegypti populations; many of which have in turn evolved resistance. Target site alteration in the acetylcholine esterase of this species has not being identified. Instead, we tracked changes in transcription of metabolic detoxification genes using the Ae. aegypti ‘Detox Chip’ microarray during five generations of temephos selection. We selected for temephos resistance in three replicates in each of six collections, five from México, and one from Perú. The response to selection was tracked in terms of lethal concentrations (LC50). Uniform upregulation was seen in the epsilon class glutathione-S-transferase genes (eGSTs) in strains from México prior to laboratory selection, while eGSTs in the Iquitos Perú strain became upregulated following five generations of temephos selection. While expression of many esterase genes (CCE) increased with selection, no single esterase was consistently upregulated and this same pattern was noted in the cytochrome P450 genes (CYP) and in other genes involved in reduction or oxidation of xenobiotics. Bioassays using GST, CCE and CYP inhibitors suggest that various CCE instead of GSTs are the main metabolic mechanism conferring resistance to temephos. We show that temephos selected strains show no cross resistance to permethrin and that genes associated with temephos selection are largely independent of those selected with permethrin in a previous study. PMID:24299217

  11. Relish2 mediates bursicon homodimer-induced prophylactic immunity in the mosquito Aedes aegypti

    PubMed Central

    Zhang, Hongwei; Dong, Shengzhang; Chen, Xi; Stanley, David; Beerntsen, Brenda; Feng, Qili; Song, Qisheng

    2017-01-01

    Bursicon is a neuropeptide hormone consisting of two cystine-knot proteins (burs α and burs β), responsible for cuticle tanning and other developmental processes in insects. Recent studies show that each bursicon subunit forms homodimers that induce prophylactic immunity in Drosophila melanogaster. Here, we investigated the hypothesis that bursicon homodimers act in prophylactic immunity in insects, and possibly arthropods, generally, using the mosquito, Aedes aegypti. We found that burs α and burs β are expressed in larvae, pupae and newly emerged adults. Treating newly emerged Ae. aegypti and D. melanogaster adults with recombinant bursicon (r-bursicon) heterodimer led to cuticle tanning in both species. Treating larvae and adults with r-bursicon homodimers led to up-regulation of five anti-microbial peptide (AMP) genes, noting the possibility that bursicon heterodimers also lead to up-regulation of these genes can not been excluded. The induced AMPs effectively suppressed the growth of bacteria in vitro. RNAi knock-down of the transcriptional factor Relish2 abolished the influence of r-bursicon homodimers on AMP production. We infer the bursicon homodimers induce expression of AMP genes via Relish2 in Ae. aegypti, as prophylactic immunity to protect mosquitoes during the vulnerable stages of each molt. PMID:28225068

  12. Release of thiotepa sterilized males into caged populations of Aedes aegypti: life table analysis.

    PubMed

    Gato, René; Companioni, Ariamys; Bruzón, Rosa Y; Menéndez, Zulema; González, Aileen; Rodríguez, Misladys

    2014-04-01

    Successful SIT trials against mosquitoes in the 1960-70s were achieved by sterilizing male mosquitoes using chemosterilants. Their use was discontinued after concerns were raised about the effect of residues on non-target organisms, although scant evidence has been published. Irradiation is an expensive process; chemosterilization could be an affordable option for implementing SIT programs in developing countries. We compare life table parameters of three Aedes aegypti populations comprising different ratios of thiotepa-treated and non-treated males in order to identify the impact on reproductive potential of the presence of sterile males. No difference was observed in the survival of the treated and untreated males. The release of thiotepa sterilized males into caged Ae. aegypti populations had no effect on death or survival probability of the individuals in the cages but the fecundity of females was significantly reduced, as evaluated by hatch rate and stable age structure parameters. The significant decreases in net reproduction rate, finite rate of natural increase and intrinsic rate of natural increase in populations including sterile males are sufficient to indicate that such populations would not be able to proliferate in natural conditions. This suggests that release of Ae. aegypti thiotepa-treated males could be effective in reducing the reproductive capability of the target population and consequently contribute to vector control.

  13. Pyrethroid resistance in Aedes aegypti and Aedes albopictus: Important mosquito vectors of human diseases.

    PubMed

    Smith, Letícia B; Kasai, Shinji; Scott, Jeffrey G

    2016-10-01

    Aedes aegypti and A. albopictus mosquitoes are vectors of important human disease viruses, including dengue, yellow fever, chikungunya and Zika. Pyrethroid insecticides are widely used to control adult Aedes mosquitoes, especially during disease outbreaks. Herein, we review the status of pyrethroid resistance in A. aegypti and A. albopictus, mechanisms of resistance, fitness costs associated with resistance alleles and provide suggestions for future research. The widespread use of pyrethroids has given rise to many populations with varying levels of resistance worldwide, albeit with substantial geographical variation. In adult A. aegypti and A. albopictus, resistance levels are generally lower in Asia, Africa and the USA, and higher in Latin America, although there are exceptions. Susceptible populations still exist in several areas of the world, particularly in Asia and South America. Resistance to pyrethroids in larvae is also geographically widespread. The two major mechanisms of pyrethroid resistance are increased detoxification due to P450-monooxygenases, and mutations in the voltage sensitive sodium channel (Vssc) gene. Several P450s have been putatively associated with insecticide resistance, but the specific P450s involved are not fully elucidated. Pyrethroid resistance can be due to single mutations or combinations of mutations in Vssc. The presence of multiple Vssc mutations can lead to extremely high levels of resistance. Suggestions for future research needs are presented.

  14. Use of transgenic Aedes aegypti in Brazil: risk perception and assessment.

    PubMed

    Paes de Andrade, Paulo; Aragão, Francisco José Lima; Colli, Walter; Dellagostin, Odir Antônio; Finardi-Filho, Flávio; Hirata, Mario Hiroyuki; Lira-Neto, Amaro de Castro; Almeida de Melo, Marcia; Nepomuceno, Alexandre Lima; Gorgônio da Nóbrega, Francisco; Delfino de Sousa, Gutemberg; Valicente, Fernando Hercos; Zanettini, Maria Helena Bodanese

    2016-10-01

    The OX513A strain of Aedes aegypti, which was developed by the British company Oxitec, expresses a self-limiting transgene that prevents larvae from developing to adulthood. In April 2014, the Brazilian National Technical Commission on Biosafety completed a risk assessment of OX513A and concluded that the strain did not present new biological risks to humans or the environment and could be released in Brazil. At that point, Brazil became the first country to approve the unconstrained release of a genetically modified mosquito. During the assessment, the commission produced a comprehensive list of - and systematically analysed - the perceived hazards. Such hazards included the potential survival to adulthood of immature stages carrying the transgene - should the transgene fail to be expressed or be turned off by exposure to sufficient environmental tetracycline. Other perceived hazards included the potential allergenicity and/or toxicity of the proteins expressed by the gene, the potential for gene flow or increased transmission of human pathogens and the occupation of vacant breeding sites by other vector species. The Zika epidemic both elevated the perceived importance of Ae. aegypti as a vector - among policy-makers and regulators as well as the general public - and increased concerns over the release of males of the OX513A strain. We have therefore reassessed the potential hazards. We found that release of the transgenic mosquitoes would still be both safe and of great potential value in the control of diseases spread by Ae. aegypti, such as chikungunya, dengue and Zika.

  15. An insulin-like peptide regulates egg maturation and metabolism in the mosquito Aedes aegypti.

    PubMed

    Brown, Mark R; Clark, Kevin D; Gulia, Monika; Zhao, Zhangwu; Garczynski, Stephen F; Crim, Joe W; Suderman, Richard J; Strand, Michael R

    2008-04-15

    Ingestion of vertebrate blood is essential for egg maturation and transmission of disease-causing parasites by female mosquitoes. Prior studies with the yellow fever mosquito, Aedes aegypti, indicated blood feeding stimulates egg production by triggering the release of hormones from medial neurosecretory cells in the mosquito brain. The ability of bovine insulin to stimulate a similar response further suggested this trigger is an endogenous insulin-like peptide (ILP). A. aegypti encodes eight predicted ILPs. Here, we report that synthetic ILP3 dose-dependently stimulated yolk uptake by oocytes and ecdysteroid production by the ovaries at lower concentrations than bovine insulin. ILP3 also exhibited metabolic activity by elevating carbohydrate and lipid storage. Binding studies using ovary membranes indicated that ILP3 had an IC(50) value of 5.9 nM that was poorly competed by bovine insulin. Autoradiography and immunoblotting studies suggested that ILP3 binds the mosquito insulin receptor (MIR), whereas loss-of-function experiments showed that ILP3 activity requires MIR expression. Overall, our results identify ILP3 as a critical regulator of egg production by A. aegypti.

  16. Larvicidal efficacy screening of Anacardaciae crude extracts on the dengue hemorrhagic vector, Aedes aegypti.

    PubMed

    Zuharah, W F; Fadzly, N; Ali, Y; Zakaria, R; Juperi, S; Asyraf, M; Dieng, H

    2014-06-01

    Vector-borne diseases are still rife because of the re-emergence of diseases transmitted by mosquitoes. The objective of this paper is to evaluate the larvicidal efficacy of crude leaf extract of Mangifera indica, Gluta renghas, and Melanochyla fasciculiflora against vector of dengue hemorrhagic fever, Aedes aegypti. These plant species are endemic species and widely distributed in Malaysian forests. Leaves of Ma. indica, G. renghas and M. fascculiflora were collected from Teluk Bahang National Park, Penang Malaysia. Fractions of leaves were segregated, air-dried, powdered and extracted using Soxhlet with methanol. The solvent was removed by using rotary evaporator to obtain the crude extract. Using WHO standard larval bioassay test method, third instar larvae of Aedes aegypti were exposed to concentration ranging from 200- 4500 ppm of methanol extract for all plant species. Larval mortality was observed after 24 hours exposure. The highest susceptibility and toxicity was recorded by Mangifera indica with the lowest concentration at 800 ppm followed by M. fasciculiflora and G. renghas. This indicates that crude plant extract is very effective in killing Ae. aegypti mosquitoes. This finding may lead to new low cost alternative, environmentally friendly method for mosquito control programs. To our knowledge, this is the first report on larvicidal bioefficacy from endemic Malaysian plants.

  17. Spatial and temporal country-wide survey of temephos resistance in Brazilian populations of Aedes aegypti

    PubMed Central

    Chediak, Mateus; G Pimenta, Fabiano; Coelho, Giovanini E; Braga, Ima A; Lima, José Bento P; Cavalcante, Karina Ribeiro LJ; de Sousa, Lindemberg C; de Melo-Santos, Maria Alice V; Macoris, Maria de Lourdes da G; de Araújo, Ana Paula; Ayres, Constância Flávia J; Andrighetti, Maria Teresa M; Gomes, Ricristhi Gonçalves de A; Campos, Kauara B; Guedes, Raul Narciso C

    2016-01-01

    The organophosphate temephos has been the main insecticide used against larvae of the dengue and yellow fever mosquito (Aedes aegypti) in Brazil since the mid-1980s. Reports of resistance date back to 1995; however, no systematic reports of widespread temephos resistance have occurred to date. As resistance investigation is paramount for strategic decision-making by health officials, our objective here was to investigate the spatial and temporal spread of temephos resistance in Ae. aegypti in Brazil for the last 12 years using discriminating temephos concentrations and the bioassay protocols of the World Health Organization. The mortality results obtained were subjected to spatial analysis for distance interpolation using semi-variance models to generate maps that depict the spread of temephos resistance in Brazil since 1999. The problem has been expanding. Since 2002-2003, approximately half the country has exhibited mosquito populations resistant to temephos. The frequency of temephos resistance and, likely, control failures, which start when the insecticide mortality level drops below 80%, has increased even further since 2004. Few parts of Brazil are able to achieve the target 80% efficacy threshold by 2010/2011, resulting in a significant risk of control failure by temephos in most of the country. The widespread resistance to temephos in Brazilian Ae. aegypti populations greatly compromise effective mosquito control efforts using this insecticide and indicates the urgent need to identify alternative insecticides aided by the preventive elimination of potential mosquito breeding sites. PMID:27143489

  18. Effects of intraspecific larval competition on adult longevity in the mosquitoes Aedes aegypti and Aedes albopictus

    PubMed Central

    LOUNIBOS, L. P.

    2009-01-01

    Larval competition is common in container-breeding mosquitoes. The impact of competition on larval growth has been thoroughly examined and findings that larval competition can lead to density-dependent effects on adult body size have been documented. The effects of larval competition on adult longevity have been less well explored. The effects of intraspecific larval densities on the longevity of adults maintained under relatively harsh environmental conditions were tested in the laboratory by measuring the longevity of adult Aedes aegypti (L.) and Aedes albopictus (Skuse) (Diptera: Culicidae) that had been reared under a range of larval densities and subsequently maintained in high- or low-humidity regimes (85% or 35% relative humidity [RH], respectively) as adults. We found significant negative effects of competition on adult longevity in Ae. aegypti, but not in Ae. albopictus. Multivariate analysis of variance suggested that the negative effect of the larval environment on the longevity of Ae. aegypti adults was most strongly associated with increased development time and decreased wing length as adults. Understanding how larval competition affects adult longevity under a range of environmental conditions is important in establishing the relationship between models of mosquito population regulation and epidemiological models of vector-borne disease transmission. PMID:19239615

  19. A meta-analysis of the factors influencing development rate variation in Aedes aegypti (Diptera: Culicidae)

    PubMed Central

    2014-01-01

    Background Development rates of Aedes aegypti are known to vary with respect to many abiotic and biotic factors including temperature, resource availability, and intraspecific competition. The relative importance of these factors and their interactions are not well established across populations. We performed meta-analysis on a dataset of development rate estimates from 49 studies. Results Meta-analytic results indicated that the environmental factor of temperature is sufficient to explain development rate variability in Ae. aegypti. While diet and density may greatly impact other developmental phenotypes, these results suggest that for development rate these factors should never be considered to the exclusion of temperature. The effect of temperature on development rate is not homogenous or constant. The sources of heterogeneity of the effect of temperature are difficult to analyze due to lack of consistent reporting of larval rearing methods. Conclusions Temperature is the most important ecological determinant of development rate in Ae. aegypti, but its effect is heterogeneous. Ignoring this heterogeneity is problematic for models of vector population and vector-borne disease transmission. PMID:24495345

  20. Temperature, Larval Diet, and Density Effects on Development Rate and Survival of Aedes aegypti (Diptera: Culicidae)

    PubMed Central

    Couret, Jannelle; Dotson, Ellen; Benedict, Mark Q.

    2014-01-01

    Many environmental factors, biotic and abiotic interact to influence organismal development. Given the importance of Aedes aegypti as a vector of human pathogens including dengue and yellow fever, understanding the impact of environmental factors such as temperature, resource availability, and intraspecific competition during development is critical for population control purposes. Despite known associations between developmental traits and factors of diet and density, temperature has been considered the primary driver of development rate and survival. To determine the relative importance of these critical factors, wide gradients of conditions must be considered. We hypothesize that 1) diet and density, as well as temperature influence the variation in development rate and survival, 2) that these factors interact, and this interaction is also necessary to understand variation in developmental traits. Temperature, diet, density, and their two-way interactions are significant factors in explaining development rate variation of the larval stages of Ae. aegypti mosquitoes. These factors as well as two and three-way interactions are significantly associated with the development rate from hatch to emergence. Temperature, but not diet or density, significantly impacted juvenile mortality. Development time was heteroskedastic with the highest variation occurring at the extremes of diet and density conditions. All three factors significantly impacted survival curves of experimental larvae that died during development. Complex interactions may contribute to variation in development rate. To better predict variation in development rate and survival in Ae. aegypti, factors of resource availability and intraspecific density must be considered in addition, but never to the exclusion of temperature. PMID:24498328

  1. Seasonal Genetic Changes of Aedes aegypti (Diptera: Culicidae) Populations in Selected Sites of Cebu City, Philippines

    PubMed Central

    Sayson, S. L.; Gloria-Soria, A.; Powell, J. R.; Edillo, F. E.

    2015-01-01

    Aedes aegypti (L.) is the primary vector of dengue virus in the Philippines, where dengue is endemic. We examined the genetic changes of Ae. aegypti collected from three selected sites in Cebu city, Philippines, during the relatively wet (2011–2012) and dry seasons (2012 and 2013). A total of 493 Ae. aegypti adults, reared in the laboratory from field-collected larvae, were analyzed using 11 microsatellite loci. Seasonal variation was observed in allele frequencies and allelic richness. Average genetic differentiation (DEST = 0.018; FST = 0.029) in both dry seasons was higher, due to reduced Ne, than in the wet season (DEST=0.006; FST=0.009). Thus, average gene flow was higher in the wet season than in the dry seasons. However, the overall FST estimate (0.02) inclusive of the two seasons showed little genetic differentiation as supported by Bayesian clustering analysis. Results suggest that during the dry season the intense selection that causes a dramatic reduction of population size favors heterozygotes, leading to small pockets of mosquitoes (refuges) that exhibit random genetic differentiation. During the wet season, the genetic composition of the population is reconstituted by the expansion of the refuges that survived the preceding dry season. Source reduction of mosquitoes during the nonepidemic dry season is thus recommended to prevent dengue re-emergence in the subsequent wet season. PMID:26335470

  2. Seasonal Genetic Changes of Aedes aegypti (Diptera: Culicidae) Populations in Selected Sites of Cebu City, Philippines.

    PubMed

    Sayson, S L; Gloria-Soria, A; Powell, J R; Edillo, F E

    2015-07-01

    Aedes aegypti (L.) is the primary vector of dengue virus in the Philippines, where dengue is endemic. We examined the genetic changes of Ae. aegypti collected from three selected sites in Cebu city, Philippines, during the relatively wet (2011-2012) and dry seasons (2012 and 2013). A total of 493 Ae. aegypti adults, reared in the laboratory from field-collected larvae, were analyzed using 11 microsatellite loci. Seasonal variation was observed in allele frequencies and allelic richness. Average genetic differentiation (DEST=0.018; FST=0.029) in both dry seasons was higher, due to reduced Ne, than in the wet season (DEST=0.006; FST=0.009). Thus, average gene flow was higher in the wet season than in the dry seasons. However, the overall FST estimate (0.02) inclusive of the two seasons showed little genetic differentiation as supported by Bayesian clustering analysis. Results suggest that during the dry season the intense selection that causes a dramatic reduction of population size favors heterozygotes, leading to small pockets of mosquitoes (refuges) that exhibit random genetic differentiation. During the wet season, the genetic composition of the population is reconstituted by the expansion of the refuges that survived the preceding dry season. Source reduction of mosquitoes during the nonepidemic dry season is thus recommended to prevent dengue re-emergence in the subsequent wet season.

  3. Spatial and temporal country-wide survey of temephos resistance in Brazilian populations of Aedes aegypti.

    PubMed

    Chediak, Mateus; G Pimenta, Fabiano; Coelho, Giovanini E; Braga, Ima A; Lima, José Bento P; Cavalcante, Karina Ribeiro Lj; Sousa, Lindemberg C de; Melo-Santos, Maria Alice V de; Macoris, Maria de Lourdes da G; Araújo, Ana Paula de; Ayres, Constância Flávia J; Andrighetti, Maria Teresa M; Gomes, Ricristhi Gonçalves de A; Campos, Kauara B; Guedes, Raul Narciso C

    2016-05-01

    The organophosphate temephos has been the main insecticide used against larvae of the dengue and yellow fever mosquito (Aedes aegypti) in Brazil since the mid-1980s. Reports of resistance date back to 1995; however, no systematic reports of widespread temephos resistance have occurred to date. As resistance investigation is paramount for strategic decision-making by health officials, our objective here was to investigate the spatial and temporal spread of temephos resistance in Ae. aegypti in Brazil for the last 12 years using discriminating temephos concentrations and the bioassay protocols of the World Health Organization. The mortality results obtained were subjected to spatial analysis for distance interpolation using semi-variance models to generate maps that depict the spread of temephos resistance in Brazil since 1999. The problem has been expanding. Since 2002-2003, approximately half the country has exhibited mosquito populations resistant to temephos. The frequency of temephos resistance and, likely, control failures, which start when the insecticide mortality level drops below 80%, has increased even further since 2004. Few parts of Brazil are able to achieve the target 80% efficacy threshold by 2010/2011, resulting in a significant risk of control failure by temephos in most of the country. The widespread resistance to temephos in Brazilian Ae. aegypti populations greatly compromise effective mosquito control efforts using this insecticide and indicates the urgent need to identify alternative insecticides aided by the preventive elimination of potential mosquito breeding sites.

  4. Intraspecific variation in desiccation survival time of Aedes aegypti (L.) mosquito eggs of Australian origin.

    PubMed

    Faull, Katherine J; Williams, Craig R

    2015-12-01

    Aedes aegypti (L.) mosquitoes preferentially oviposit in natural and artificial receptacles where their eggs are able to withstand drying as water levels fluctuate. Desiccation-resistant eggs also increase the potential for establishment in non-native habitats while providing logistical impediments to control programs. Viability and mean survival times of eggs stored under three dryness conditions for up to 367 days were investigated among three field-derived colonies of Australian Ae. aegypti to understand variation in desiccation survival. Further investigations compared egg survival between an established colony and its wild counterpart. Our results confirmed that Ae. aegypti eggs can withstand desiccation for extended periods of time with approximately 2-15% egg viability recorded after one year and viability remaining above 88% under all conditions through 56 days. Intraspecific variations in egg survival times were recorded, suggesting local adaptation while each of the colonies demonstrated a consistent preference for higher humidity. Egg volume varied between the populations, suggesting a relationship between egg volume and survival time, with the marginally larger eggs (Charters Towers and Innisfail) having greater desiccation resistance over the range of conditions. The strong survivorship of Charters Towers eggs in dry, warm conditions demonstrates the adaptive significance of a desiccation-resistant egg.

  5. Differential transcription profiles in Aedes aegypti detoxification genes after temephos selection.

    PubMed

    Saavedra-Rodriguez, K; Strode, C; Flores, A E; Garcia-Luna, S; Reyes-Solis, G; Ranson, H; Hemingway, J; Black, W C

    2014-04-01

    The mosquito Aedes aegypti is the main vector of Dengue and Yellow Fever flaviviruses. The organophosphate insecticide temephos is a larvicide that is used globally to control Ae. aegypti populations; many of which have in turn evolved resistance. Target site alteration in the acetylcholine esterase of this species has not being identified. Instead, we tracked changes in transcription of metabolic detoxification genes using the Ae. aegypti 'Detox Chip' microarray during five generations of temephos selection. We selected for temephos resistance in three replicates in each of six collections, five from Mexico, and one from Peru. The response to selection was tracked in terms of lethal concentrations. Uniform upregulation was seen in the epsilon class glutathione-S-transferase (eGST) genes in strains from Mexico prior to laboratory selection, while eGSTs in the Iquitos Peru strain became upregulated after five generations of temephos selection. While expression of many carboxyl/cholinesterase esterase (CCE) genes increased with selection, no single esterase was consistently upregulated and this same pattern was noted in the cytochrome P450 monooxygenase (CYP) genes and in other genes involved in reduction or oxidation of xenobiotics. Bioassays using glutathione-S-transferase (GST), CCE and CYP inhibitors suggest that various CCEs instead of GSTs are the main metabolic mechanism conferring resistance to temephos. We show that temephos-selected strains show no cross resistance to permethrin and that genes associated with temephos selection are largely independent of those selected with permethrin in a previous study.

  6. In silico models for predicting vector control chemicals targeting Aedes aegypti.

    PubMed

    Devillers, J; Lagneau, C; Lattes, A; Garrigues, J C; Clémenté, M M; Yébakima, A

    2014-01-01

    Human arboviral diseases have emerged or re-emerged in numerous countries worldwide due to a number of factors including the lack of progress in vaccine development, lack of drugs, insecticide resistance in mosquitoes, climate changes, societal behaviours, and economical constraints. Thus, Aedes aegypti is the main vector of the yellow fever and dengue fever flaviviruses and is also responsible for several recent outbreaks of the chikungunya alphavirus. As for the other mosquito species, the A. aegypti control relies heavily on the use of insecticides. However, because of increasing resistance to the different families of insecticides, reduction of Aedes populations is becoming increasingly difficult. Despite the unquestionable utility of insecticides in fighting mosquito populations, there are very few new insecticides developed and commercialized for vector control. This is because the high cost of the discovery of an insecticide is not counterbalanced by the 'low profitability' of the vector control market. Fortunately, the use of quantitative structure-activity relationship (QSAR) modelling allows the reduction of time and cost in the discovery of new chemical structures potentially active against mosquitoes. In this context, the goal of the present study was to review all the existing QSAR models on A. aegypti. The homology and pharmacophore models were also reviewed. Specific attention was paid to show the variety of targets investigated in Aedes in relation to the physiology and ecology of the mosquito as well as the diversity of the chemical structures which have been proposed, encompassing man-made and natural substances.

  7. A novel autocidal ovitrap for the surveillance and control of Aedes aegypti.

    PubMed

    Barrera, Roberto; Mackay, Andrew J; Amador, Manuel

    2013-09-01

    We describe an inexpensive autocidal ovitrap for Aedes aegypti that uses cross-linked polyacrylamide (PAM) gel as the oviposition substrate. Aedes aegypti females readily laid eggs on PAM gel that had been hydrated with either hay infusion or water. Aedes aegypti larvae that hatched from their eggs desiccated on the surface of the PAM gel. We tested the effects of gel hydration, texture, and type of attractant on trap performance, and compared the capture rates of standard ovitraps with those of PAM gel ovitraps in the field. The results showed that the number of eggs did not vary over a range of gel hydration levels (40-100%) and that more eggs were recovered from ovitraps containing coarse gel than from those containing homogenized gel. The PAM gel hydrated with hay infusion was more attractive to gravid female mosquitoes than gel hydrated with water. In the field, the number of eggs recovered from autocidal ovitraps with PAM gel was similar to that recovered from standard ovitraps with hay infusion.

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

    PubMed

    Koenraadt, C J M; Harrington, L C

    2008-01-01

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

  9. Biosynthesis of silver nanoparticles using Bacillus thuringiensis against dengue vector, Aedes aegypti (Diptera: Culicidae).

    PubMed

    Banu, A Najitha; Balasubramanian, C; Moorthi, P Vinayaga

    2014-01-01

    The present study reveals the larvicidal activity of silver nanoparticles (AgNPs) synthesized by Bacillus thuringiensis (Bt) against Aedes aegypti responsible for the diseases of public health importance. The Bt-AgNPs were characterized by using UV-visible spectrophotometer followed by scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy. A surface plasmon resonance spectrum of AgNps was obtained at 420 nm. The particle sizes were measured through SEM imaging ranging from 43.52 to 142.97 nm. The Bt-AgNPs has also given a characteristic peak at 3 keV in EDX image. Interestingly, the mortality rendered by Bt-AgNPs was comparatively high than that of the control against third-instar larvae of A. aegypti (LC50 0.10 ppm and LC90 0.39 ppm) in all the tested concentrations, viz. 0.03, 0.06, 0.09, 0.12, and 0.15 ppm. Hence, Bt-AgNPs would be significantly used as a potent mosquito larvicide against A. aegypti.

  10. In silico models for predicting vector control chemicals targeting Aedes aegypti

    PubMed Central

    Devillers, J.; Lagneau, C.; Lattes, A.; Garrigues, J.C.; Clémenté, M.M.; Yébakima, A.

    2014-01-01

    Human arboviral diseases have emerged or re-emerged in numerous countries worldwide due to a number of factors including the lack of progress in vaccine development, lack of drugs, insecticide resistance in mosquitoes, climate changes, societal behaviours, and economical constraints. Thus, Aedes aegypti is the main vector of the yellow fever and dengue fever flaviviruses and is also responsible for several recent outbreaks of the chikungunya alphavirus. As for the other mosquito species, the A. aegypti control relies heavily on the use of insecticides. However, because of increasing resistance to the different families of insecticides, reduction of Aedes populations is becoming increasingly difficult. Despite the unquestionable utility of insecticides in fighting mosquito populations, there are very few new insecticides developed and commercialized for vector control. This is because the high cost of the discovery of an insecticide is not counterbalanced by the ‘low profitability’ of the vector control market. Fortunately, the use of quantitative structure–activity relationship (QSAR) modelling allows the reduction of time and cost in the discovery of new chemical structures potentially active against mosquitoes. In this context, the goal of the present study was to review all the existing QSAR models on A. aegypti. The homology and pharmacophore models were also reviewed. Specific attention was paid to show the variety of targets investigated in Aedes in relation to the physiology and ecology of the mosquito as well as the diversity of the chemical structures which have been proposed, encompassing man-made and natural substances. PMID:25275884

  11. Behavioral responses of catnip (Nepeta cataria l.)by two species of mosquitoes, Aedes aegypti (l.) and Anopheles harrisoni harbach and manguin, in Thailand.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An investigation of the biological effect of catnip oil (Nepeta cataria L.) on the behavioral response of field collected Ae. aegypti and An. harrisoni were conducted using an automated excito-repellency test system. Aedes aegypti showed significant higher escape rates from the contact chamber at 5%...

  12. Aedes (Stegomyia) aegypti in the continental United States: a vector at the cool margin of its geographic range.

    PubMed

    Eisen, Lars; Moore, Chester G

    2013-05-01

    After more than a half century without recognized local dengue outbreaks in the continental United States, there were recent outbreaks of autochthonous dengue in the southern parts of Texas (2004-2005) and Florida (2009-2011). This dengue reemergence has provoked interest in the extent of the future threat posed by the yellow fever mosquito, Aedes (Stegomyia) aegypti (L.), the primary vector of dengue and yellow fever viruses in urban settings, to human health in the continental United States. Ae. aegypti is an intriguing example of a vector species that not only occurs in the southernmost portions of the eastern United States today but also is incriminated as the likely primary vector in historical outbreaks of yellow fever as far north as New York, Philadelphia, and Boston, from the 1690s to the 1820s. For vector species with geographic ranges limited, in part, by low temperature and cool range margins occurring in the southern part of the continental United States, as is currently the case for Ae. aegypti, it is tempting to speculate that climate warming may result in a northward range expansion (similar to that seen for Ixodes tick vectors of Lyme borreliosis spirochetes in Scandinavia and southern Canada in recent decades). Although there is no doubt that climate conditions directly impact many aspects of the life history of Ae. aegypti, this mosquito also is closely linked to the human environment and directly influenced by the availability of water-holding containers for oviposition and larval development. Competition with other container-inhabiting mosquito species, particularly Aedes (Stegomyia) albopictus (Skuse), also may impact the presence and local abundance of Ae. aegypti. Field-based studies that focus solely on the impact of weather or climate factors on the presence and abundance of Ae. aegypti, including assessments of the potential impact of climate warming on the mosquito's future range and abundance, do not consider the potential confounding

  13. ConSCRIPT

    PubMed Central

    Mottarella, Scott E.; Rosa, Mario; Bangura, Abdul; Bernstein, Herbert J.; Craig, Paul A.

    2011-01-01

    The aim of the Structural Biology Extensible Visualization Scripting Language (SBEVSL) project is to allow users who are experts in one scripting language to use that language in a second molecular visualization environment without requiring the user to learn a new scripting language. ConSCRIPT, the first SBEVSL release, is a plug-in for PyMOL that accepts RasMol scripting commands either as premade scripts or as line-by-line entries from PyMOL's own command line. The plug-in is available for download at http://sourceforge.net/projects/sbevsl/files in the ConSCRIPT folder. PMID:21567873

  14. Effect of Aedes aegypti exposure to spatial repellent chemicals on BG-Sentinel™ trap catches

    PubMed Central

    2013-01-01

    Background An integrated approach to reduce densities of adult Aedes aegypti inside homes is currently being evaluated under experimentally controlled field conditions. The strategy combines a spatial repellent (SR) treatment (applied indoors) with the Biogents Sentinel™ (BGS) mosquito trap positioned in the outdoor environment. In essence, when combined, the goal is to create a push-pull mechanism that will reduce the probability of human-vector contact. The current study measured BGS recapture rates of Ae. aegypti test cohorts that were exposed to either SR or control (chemical-free) treatments within experimental huts. The objective was to define what, if any, negative impact SR may have on BGS trap efficacy (i.e., reduced BGS collection). Methods Aedes aegypti females were exposed to SR compounds within experimental huts in the form of either treated fabric (DDT and transfluthrin) or mosquito coil (metofluthrin). Test cohorts were released within individual screen house cubicles, each containing 4 BGS traps, following SR exposure according to treatment. Two separate test cohorts were evaluated: (i) immediate release (IR) exposed from 06:00–12:00 hours and released at 12:00 hours and (ii) delayed release (DR) exposed from12:00–18:00 hours and released at 05:30 hours the following day. BGS recapture was monitored at 09:30, 13:30 and 15:30 hours and the cumulative recapture by time point quantified. Results Exposure of Ae. aegypti females to either DDT or metofluthrin did not significantly impact BGS capture as compared to cohorts of non-exposed females. This was true for both IR and DR exposure populations. IR cohorts exposed to transfluthrin resulted in significantly lower BGS recapture compared to matched controls but this effect was primarily due to high mosquito mortality during transfluthrin trials. Conclusion Our data indicate no more than minor and short-lived impacts (i.e., reduced attraction) on BGS trap catches following exposure to the

  15. Functional and Genetic Characterization of Neuropeptide Y-Like Receptors in Aedes aegypti

    PubMed Central

    Liesch, Jeff; Bellani, Lindsay L.; Vosshall, Leslie B.

    2013-01-01

    Background Female Aedes aegypti mosquitoes are the principal vector for dengue fever, causing 50–100 million infections per year, transmitted between human and mosquito by blood feeding. Ae. aegypti host-seeking behavior is known to be inhibited for three days following a blood meal by a hemolymph-borne humoral factor. Head Peptide-I is a candidate peptide mediating this suppression, but the mechanism by which this peptide alters mosquito behavior and the receptor through which it signals are unknown. Methodology/Principal Findings Head Peptide-I shows sequence similarity to short Neuropeptide-F peptides (sNPFs) that have been implicated in feeding behaviors and are known to signal through Neuropeptide Y (NPY)-Like Receptors (NPYLRs). We identified eight NPYLRs in the Ae. aegypti genome and screened each in a cell-based calcium imaging assay for sensitivity against a panel of peptides. Four of the Ae. aegypti NPYLRs responded to one or more peptide ligands, but only NYPLR1 responded to Head Peptide-I as well as sNPFs. Two NPYLR1 homologues identified in the genome of the Lyme disease vector, Ixodes scapularis, were also sensitive to Head Peptide-I. Injection of synthetic Head Peptide-I and sNPF-3 inhibited host-seeking behavior in non-blood-fed female mosquitoes, whereas control injections of buffer or inactive Head Peptide-I [Cys10] had no effect. To ask if NPYLR1 is necessary for blood-feeding-induced host-seeking inhibition, we used zinc-finger nucleases to generate five independent npylr1 null mutant strains and tested them for behavioral abnormalities. npylr1 mutants displayed normal behavior in locomotion, egg laying, sugar feeding, blood feeding, host seeking, and inhibition of host seeking after a blood meal. Conclusions In this work we deorphanized four Ae. aegypti NPYLRs and identified NPYLR1 as a candidate sNPF receptor that is also sensitive to Head Peptide-I. Yet npylr1 alone is not required for host-seeking inhibition and we conclude that other

  16. Observations on possible competitive displacement between populations of Aedes aegypti Linnaeus and Aedes albopictus Skuse in Calcutta*

    PubMed Central

    Gilotra, Sushil K.; Rozeboom, Lloyd E.; Bhattacharya, N. C.

    1967-01-01

    The possibility of competitive displacement in Calcutta between Aedes aegypti, a known vector of arboviruses, and A. albopictus, a suspected vector, was explored by general collections of immature stages from all types of breeding-places and by exposing oviposition traps in tenement houses, and gardens in urban, suburban, and rural environments. A. aegypti was predominant in houses and tenements in urban areas, but A. albopictus was not excluded. Both species occurred in about equal densities in small urban gardens. In suburban and rural areas, A. albopictus was predominant, or the only one of the two species present. It readily entered houses for the purpose of oviposition, especially in the absence of A. aegypti. It is suggested that the two species are exhibiting the effect of competitive displacement, with A. aegypti being favoured in urban premises and A. albopictus in the outdoor environment of suburban and rural areas, while in small urban gardens there is a state of equilibrium in which the densities of the two populations are about equal. The possibility cannot be excluded that eradication of A. aegypti in the city might lead to an increase in the A. albopictus population in houses and tenement dwellings. PMID:5301385

  17. Population Dynamics of Aedes aegypti and Dengue as Influenced by Weather and Human Behavior in San Juan, Puerto Rico

    PubMed Central

    Barrera, Roberto; Amador, Manuel; MacKay, Andrew J.

    2011-01-01

    Previous studies on the influence of weather on Aedes aegypti dynamics in Puerto Rico suggested that rainfall was a significant driver of immature mosquito populations and dengue incidence, but mostly in the drier areas of the island. We conducted a longitudinal study of Ae. aegypti in two neighborhoods of the metropolitan area of San Juan city, Puerto Rico where rainfall is more uniformly distributed throughout the year. We assessed the impacts of rainfall, temperature, and human activities on the temporal dynamics of adult Ae. aegypti and oviposition. Changes in adult mosquitoes were monitored with BG-Sentinel traps and oviposition activity with CDC enhanced ovitraps. Pupal surveys were conducted during the drier and wetter parts of the year in both neighborhoods to determine the contribution of humans and rains to mosquito production. Mosquito dynamics in each neighborhood was compared with dengue incidence in their respective municipalities during the study. Our results showed that: 1. Most pupae were produced in containers managed by people, which explains the prevalence of adult mosquitoes at times when rainfall was scant; 2. Water meters were documented for the first time as productive habitats for Ae. aegypti; 3. Even though Puerto Rico has a reliable supply of tap water and an active tire recycling program, water storage containers and discarded tires were important mosquito producers; 4. Peaks in mosquito density preceded maximum dengue incidence; and 5. Ae. aegypti dynamics were driven by weather and human activity and oviposition was significantly correlated with dengue incidence. PMID:22206021

  18. Phylogeography of Aedes (Stegomyia) aegypti (L.) and Aedes (Stegomyia) albopictus (Skuse) (Diptera: Culicidae) based on mitochondrial DNA variations.

    PubMed

    Mousson, Laurence; Dauga, Catherine; Garrigues, Thomas; Schaffner, Francis; Vazeille, Marie; Failloux, Anna-Bella

    2005-08-01

    Aedes (Stegomyia) aegypti (l.) and Aedes (Stegomyia) albopictus (Skuse) are the most important vectors of the dengue and yellow-fever viruses. Both took advantage of trade developments to spread throughout the tropics from their native area: A. aegypti originated from Africa and a. albopictus from South-East Asia. We investigated the relationships between A. aegypti and A. albopictus mosquitoes based on three mitochondrial-DNA genes (cytochrome b, cytochrome oxidase I and NADH dehydrogenase subunit 5). Little genetic variation was observed for a. albopictus, probably owing to the recent spreading of the species via human activities. For A. aegypti, most populations from South America were found to be genetically similar to populations from South-East Asia (Thailand and Vietnam), except for one sample from Boa Vista (northern Amazonia), which was more closely related to samples from Africa (Guinea and Ivory Coast). This suggests that African populations of A. aegypti introduced during the slave trade have persisted in Boa Vista, resisting eradication campaigns.

  19. Evaluation of reference genes at different developmental stages for quantitative real-time PCR in Aedes aegypti.

    PubMed

    Dzaki, Najat; Ramli, Karima N; Azlan, Azali; Ishak, Intan H; Azzam, Ghows

    2017-03-16

    The mosquito Aedes aegypti (Ae. aegypti) is the most notorious vector of illness-causing viruses such as Dengue, Chikugunya, and Zika. Although numerous genetic expression studies utilizing quantitative real-time PCR (qPCR) have been conducted with regards to Ae. aegypti, a panel of genes to be used suitably as references for the purpose of expression-level normalization within this epidemiologically important insect is presently lacking. Here, the usability of seven widely-utilized reference genes i.e. actin (ACT), eukaryotic elongation factor 1 alpha (eEF1α), alpha tubulin (α-tubulin), ribosomal proteins L8, L32 and S17 (RPL8, RPL32 and RPS17), and glyceraldeyde 3-phosphate dehydrogenase (GAPDH) were investigated. Expression patterns of the reference genes were observed in sixteen pre-determined developmental stages and in cell culture. Gene stability was inferred from qPCR data through three freely available algorithms i.e. BestKeeper, geNorm, and NormFinder. The consensus rankings generated from stability values provided by these programs suggest a combination of at least two genes for normalization. ACT and RPS17 are the most dependably expressed reference genes and therefore, we propose an ACT/RPS17 combination for normalization in all Ae. aegypti derived samples. GAPDH performed least desirably, and is thus not a recommended reference gene. This study emphasizes the importance of validating reference genes in Ae. aegypti for qPCR based research.

  20. Microclimate and human factors in the divergent ecology of Aedes aegypti along the Arizona, U.S./Sonora, MX border.

    PubMed

    Hayden, Mary H; Uejio, Christopher K; Walker, Kathleen; Ramberg, Frank; Moreno, Rafael; Rosales, Cecilia; Gameros, Mercedes; Mearns, Linda O; Zielinski-Gutierrez, Emily; Janes, Craig R

    2010-08-01

    This study examined the association of human and environmental factors with the presence of Aedes aegypti, the vector for dengue fever and yellow fever viruses, in a desert region in the southwest United States and northwest Mexico. Sixty-eight sites were longitudinally surveyed along the United States-Mexico border in Tucson, AZ, Nogales, AZ, and Nogales, Sonora during a 3-year period. Aedes aegypti presence or absence at each site was measured three times per year using standard oviposition traps. Maximum and minimum temperature and relative humidity were measured hourly at each site. Field inventories were conducted to measure human housing factors potentially affecting mosquito presence, such as the use of air-conditioning and evaporative coolers, outdoor vegetation cover, and access to piped water. The results showed that Ae. aegypti presence was highly variable across space and time. Aedes aegypti presence was positively associated with highly vegetated areas. Other significant variables included microclimatic differences and access to piped water. This study demonstrates the importance of microclimate and human factors in predicting Ae. aegypti distribution in an arid environment.

  1. Evaluation of BG-sentinel trap trapping efficacy for Aedes aegypti (Diptera: Culicidae) in a visually competitive environment.

    PubMed

    Ball, Tamara S; Ritchie, Scott R

    2010-07-01

    The BG-Sentinel (BGS) trap uses visual and olfactory cues as well as convection currents to attract Aedes aegypti (L.). The impact of the visual environment on trapping efficacy of the BGS trap for Ae. aegypti was investigated. Four- to 5-d nulliparous female and male Ae. aegypti were released into a semicontrolled room to evaluate the effect of the presence, reflectance, and distribution of surrounding harborage sites on BGS trapping efficacy. Low-reflective (dark) harborage sites near the BGS had a negative effect on both male and nulliparous female recapture rates; however, a more pronounced effect was observed in males. The distribution (clustered versus scattered) of dark harborage sites did not significantly affect recapture rates in either sex. In a subsequent experiment, the impact of oviposition sites on the recapture rate of gravid females was investigated. Although gravid females went to the oviposition sites and deposited eggs, the efficacy of the BGS in recapturing gravid females was not compromised. Ae. aegypti sampling in the field will mostly occur in the urban environment, whereby the BGS will be among oviposition sites and dark harborage areas in the form of household items and outdoor clutter. In addition to understanding sampling biases of the BGS, estimations of the adult population size and structure can be further adjusted based on an understanding of the impact of dark harborage sites on trap captures. Outcomes from this suite of experiments provide us with important considerations for trap deployment and interpretation of Ae. aegypti samples from the BGS trap.

  2. Evaluation of reference genes at different developmental stages for quantitative real-time PCR in Aedes aegypti

    PubMed Central

    Dzaki, Najat; Ramli, Karima N.; Azlan, Azali; Ishak, Intan H.; Azzam, Ghows

    2017-01-01

    The mosquito Aedes aegypti (Ae. aegypti) is the most notorious vector of illness-causing viruses such as Dengue, Chikugunya, and Zika. Although numerous genetic expression studies utilizing quantitative real-time PCR (qPCR) have been conducted with regards to Ae. aegypti, a panel of genes to be used suitably as references for the purpose of expression-level normalization within this epidemiologically important insect is presently lacking. Here, the usability of seven widely-utilized reference genes i.e. actin (ACT), eukaryotic elongation factor 1 alpha (eEF1α), alpha tubulin (α-tubulin), ribosomal proteins L8, L32 and S17 (RPL8, RPL32 and RPS17), and glyceraldeyde 3-phosphate dehydrogenase (GAPDH) were investigated. Expression patterns of the reference genes were observed in sixteen pre-determined developmental stages and in cell culture. Gene stability was inferred from qPCR data through three freely available algorithms i.e. BestKeeper, geNorm, and NormFinder. The consensus rankings generated from stability values provided by these programs suggest a combination of at least two genes for normalization. ACT and RPS17 are the most dependably expressed reference genes and therefore, we propose an ACT/RPS17 combination for normalization in all Ae. aegypti derived samples. GAPDH performed least desirably, and is thus not a recommended reference gene. This study emphasizes the importance of validating reference genes in Ae. aegypti for qPCR based research. PMID:28300076

  3. Population dynamics of Aedes aegypti and dengue as influenced by weather and human behavior in San Juan, Puerto Rico.

    PubMed

    Barrera, Roberto; Amador, Manuel; MacKay, Andrew J

    2011-12-01

    Previous studies on the influence of weather on Aedes aegypti dynamics in Puerto Rico suggested that rainfall was a significant driver of immature mosquito populations and dengue incidence, but mostly in the drier areas of the island. We conducted a longitudinal study of Ae. aegypti in two neighborhoods of the metropolitan area of San Juan city, Puerto Rico where rainfall is more uniformly distributed throughout the year. We assessed the impacts of rainfall, temperature, and human activities on the temporal dynamics of adult Ae. aegypti and oviposition. Changes in adult mosquitoes were monitored with BG-Sentinel traps and oviposition activity with CDC enhanced ovitraps. Pupal surveys were conducted during the drier and wetter parts of the year in both neighborhoods to determine the contribution of humans and rains to mosquito production. Mosquito dynamics in each neighborhood was compared with dengue incidence in their respective municipalities during the study. Our results showed that: 1. Most pupae were produced in containers managed by people, which explains the prevalence of adult mosquitoes at times when rainfall was scant; 2. Water meters were documented for the first time as productive habitats for Ae. aegypti; 3. Even though Puerto Rico has a reliable supply of tap water and an active tire recycling program, water storage containers and discarded tires were important mosquito producers; 4. Peaks in mosquito density preceded maximum dengue incidence; and 5. Ae. aegypti dynamics were driven by weather and human activity and oviposition was significantly correlated with dengue incidence.

  4. Aedes aegypti (L.) in Latin American and Caribbean region: With growing evidence for vector adaptation to climate change?

    PubMed

    Chadee, Dave D; Martinez, Raymond

    2016-04-01

    Within Latin America and the Caribbean region the impact of climate change has been associated with the effects of rainfall and temperature on seasonal outbreaks of dengue but few studies have been conducted on the impacts of climate on the behaviour and ecology of Aedes aegypti mosquitoes.This study was conducted to examine the adaptive behaviours currently being employed by A. aegypti mosquitoes exposed to the force of climate change in LAC countries. The literature on the association between climate and dengue incidence is small and sometimes speculative. Few laboratory and field studies have identified research gaps. Laboratory and field experiments were designed and conducted to better understand the container preferences, climate-associated-adaptive behaviour, ecology and the effects of different temperatures and light regimens on the life history of A. aegypti mosquitoes. A. aegypti adaptive behaviours and changes in container preferences demonstrate how complex dengue transmission dynamics is, in different ecosystems. The use of underground drains and septic tanks represents a major behaviour change identified and compounds an already difficult task to control A. aegypti populations. A business as usual approach will exacerbate the problem and lead to more frequent outbreaks of dengue and chikungunya in LAC countries unless both area-wide and targeted vector control approaches are adopted. The current evidence and the results from proposed transdisciplinary research on dengue within different ecosystems will help guide the development of new vector control strategies and foster a better understanding of climate change impacts on vector-borne disease transmission.

  5. Natural transovarial dengue virus infection rate in both sexes of dark and pale forms of Aedes aegypti from an urban area of Bangkok, Thailand.

    PubMed

    Thongrungkiat, Supatra; Wasinpiyamongkol, Ladawan; Maneekan, Pannamas; Prummongkol, Samrerng; Samung, Yudthana

    2012-09-01

    Transovarial dengue virus infection status of two forms of adult Aedes aegypti (dark or Ae. aegypti type form and pale or form queenslandensis), reared from field-collected larval and pupal stages, was determined by one-step RT-PCR and dengue viral serotype by nested-PCR. Natural transovarial transmission (TOT) of dengue virus was detected in the two Ae. aegypti forms, and in both adult males and females. Male Ae. aegypti had a higher rate of TOT dengue virus infection than female. The overall minimum infection rate among the male and female populations was 19.5 and 12.3 per 1,000 mosquitoes, respectively. All four dengue serotypes were detected in mosquito samples, with DEN-4 being the predominant serotype. Thus, both male and female Ae. aegypti have influences on the epidemiology of dengue virus transmission.

  6. Evaluation of the inhibition of egg laying, larvicidal effects, and bloodfeeding success of Aedes aegypti exposed to permethrin- and bifenthrin-treated military tent fabric.

    PubMed

    Frances, S P; Huggins, R L; Cooper, R D

    2008-12-01

    Laboratory studies were conducted to evaluate the effects of treating military canvas tent fabric with bifenthrin and permethrin on the survival of the eggs and larvae of Aedes aegypti. Gravid female Ae. aegypti were able to oviposit on tent canvas treated with either bifenthrin or permethrin. However, none of the eggs laid on treated canvas hatched, and no larvae added to water in treated trays survived. Low residual concentrations of bifenthrin and permethrin on treated canvas prevented the development of eggs and larvae of Ae. aegypti. Inhibition of bloodfeeding was shown when Ae. aegypti adults were exposed to lower concentrations (10-50% of operational concentrations) of bifenthrin- and permethrin-treated canvas tent fabric. These experiments have shown that military tent canvas treated with either bifenthrin or permethrin can reduce the development of Ae. aegypti eggs and larvae and reduce bloodfeeding success of adults.

  7. Selective oviposition by Aedes aegypti (Diptera: culicidae) in response to Mesocyclops longisetus (Copepoda: Cyclopoidea) under laboratory and field conditions.

    PubMed

    Torres-Estrada, J L; Rodríguez, M H; Cruz-López, L; Arredondo-Jimenez, J I

    2001-03-01

    The influence of predacious Mesocyclops longisetus Thiebaud on the selection of oviposition sites by prey Aedes aegypti (L.) was studied under laboratory and field conditions. In both cases, gravid Ae. aegypti females were significantly more attracted to ovitraps containing copepods or to ovitraps with water in which copepods were held previously than to distilled water. Monoterpene and sesquiterpene compounds including 3-carene, alpha-terpinene, alpha-copaene, alpha-longipinene, alpha-cedrene, and delta-cadinene were found in hexane extracts of copepods by gas chromatography and mass spectrometry analyses. These compounds may be responsible for attracting gravid Ae. aegypti females and may increase the number of potential prey for the copepod.

  8. [Genetic variability of Aedes aegypti determined by mitochondrial gene ND4 analysis in eleven endemic areas for dengue in Peru].

    PubMed

    Yáñez, Pamela; Mamani, Enrique; Valle, Jorge; García, María Paquita; León, Walter; Villaseca, Pablo; Torres, Dina; Cabezas, César

    2013-04-01

    In order to establish the genetic variability of Aedes aegypti determined by the analysis of the MT-ND4 gene, in eleven endemic regions for dengue in Peru, 51 samples of Ae. Aegypti were tested. The genetic variability was determined through the amplification and sequencing of a fragment of 336 base-pairs of MT ND4, the analysis of intra-specific phylogeny was conducted with the Network Ver. 4.6.10 program; and the phylogenetic analysis, with the Neighbor Joining distance method. The presence of five haplotypes of Ae. Aegypti grouped in two lineages was identified: the first one includes haplotypes 1, 3 and 5, and the second one comprises haplotypes 2 and 4. The geographic distribution of each of the haplotypes found is also shown. It is concluded that this variability is caused by the active migration of this vector and the human activity-mediated passive migration.

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-10-01

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

  11. Polygamy: the possibly significant behavior of Aedes aegypti and Aedes albopictus in relation to the efficient transmission of dengue virus.

    PubMed

    Choochote, W; Tippawangkosol, P; Jitpakdi, A; Sukontason, K L; Pitasawat, B; Sukontason, K; Jariyapan, N

    2001-12-01

    The polygamous behavior of male Aedes aegypti (L.) and Ae. albopictus (Skuse) was investigated by co-habiting a newly-emerged male and females in a 30 cm3 cage (1 male: 20 females) for up to 5 consecutive days. As determined by insemination rates, the results indicated that one Ae. aegypti and Ae. albopictus male could successfully mate with 1.10 (0-4), 4.10 (1-8), 5.40 (4-8), 5.10 (2-8), 5.15 (3-9) and 0.20 (0-3), 1.70 (0-3), 2.35 (1-4), 2.30 (0-4), 2.35 (1-4) Ae. aegypti and Ae. albopictus females, respectively on day 1,2,3,4 and 5 consecutively. The possibly significant role of their polygamy in relation to dengue virus transmission is discussed.

  12. Control of aedes aegypti breeding in desert coolers and tires by use of Bacillus thuringiensis var. Israelensis formulation.

    PubMed

    Batra, C P; Mittal, P K; Adak, T

    2000-12-01

    Three different formulations of Bacillus thuringiensis var. israelensis (Bti) were evaluated for their efficacy against immature Aedes aegypti in desert coolers and tires. Three formulations, viz., VectoBac tablets, VectoBac granules, and Bacticide powder, at the application rate of 0.75, 2, and 1 g per cooler, respectively, and VectoBac tablets at 0.75 and 0.375 g per tire, were evaluated. In coolers and tires, 100% reduction in the abundance of late larval instars of Ae. aegypti was observed for a period of 2 and 3 wk, respectively. The possibility of using tablets and capsules filled with Bti granules and powder formulation by individuals or communities for control of Ae. aegypti breeding has been discussed in view of the increasing outbreaks of dengue and dengue hemorrhagic fever in India. Use of these formulations over conventional methods is better and more user-friendly.

  13. Evaluation of Insect Growth Regulators Against Field-Collected Aedes aegypti and Aedes albopictus (Diptera: Culicidae) from Malaysia.

    PubMed

    Lau, Koon Weng; Chen, Chee Dhang; Lee, Han Lim; Norma-Rashid, Yusoff; Sofian-Azirun, Mohd

    2015-03-01

    Susceptibility status of Aedes aegypti (L.) and Aedes albopictus Skuse larvae obtained from 12 states in Malaysia were evaluated against five insect growth regulators (IGRs), namely, pyriproxyfen, methoprene, diflubenzuron, cyromazine, and novaluron under laboratory conditions. Field populations of Ae. aegypti exhibited moderate resistance toward methoprene and low resistance toward pyriproxyfen, with resistance ratios of 12.7 and 1.4, respectively, but susceptibility to diflubenzuron, cyromazine, and novaluron. On the other hand, field populations of Ae. albopictus exhibited low resistance against diflubenzuron and novaluron, with resistance ratio of 2.1 and 1.0, respectively, but susceptibility to other tested IGRs. Our study concluded that the tested IGRs provide promising results and can be used to control field population of Ae. aegypti and Ae. albopictus, especially cyromazine. The use of IGR should be considered as an alternative when larvae develop resistance to conventional insecticides.

  14. Coexistence of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in Peninsular Florida Two Decades After Competitive Displacements.

    PubMed

    Lounibos, L Philip; Bargielowski, Irka; Carrasquilla, María Cristina; Nishimura, Naoya

    2016-11-01

    The spread of Aedes albopictus (Skuse) eastward in the mid-1980s from its initial establishment in Houston, TX, was associated with rapid declines and local disappearances of Aedes aegypti (L.) in Gulf Coast states and Florida where annual larval surveillance during the early 1990s described temporal and spatial patterns of competitive displacements in cemeteries and tire shops. Approximately 20 yr later in 2013-2014, we re-visited former collection sites and sampled aquatic immatures of these two species from tire shops in 10 cities on State Route 441 and from 9 cemeteries from Lakeland to Miami in southwest Florida. In the recent samples Ae. aegypti was recovered from three central Florida cities where it had not been detected in 1994, but its northern limit on Rte. 441, Apopka, did not change. Other evidence, such as trends at a few cemeteries, suggested a moderate resurgence of this species since 1994. Cage experiments that exposed female progeny of Ae. aegypti from recent Florida collection sites to interspecific mating by Ae. albopictus males showed that females from coexistence sites had evolved resistance to cross-mating, but Ae. aegypti from sites with no Ae. albopictus were relatively susceptible to satyrization. Habitat classifications of collection sites were reduced by principal component (PC) analysis to four variables that accounted for > 99% of variances; PCs with strong positive loadings for tree cover and ground vegetation were associated with collection sites yielding only Ae. albopictus Within the coexistence range of the two species, the numbers of Ae. aegypti among total Aedes collected were strongly correlated in stepwise logistic regression models with two habitat-derived PCs, distance from the coast, and annual rainfall and mean maximum temperatures at the nearest weather station. Subtle increases in the range of Ae. aegypti since its previous displacements are interpreted in the context of the evolution of resistance to mating

  15. Historical environmental change in Africa drives divergence and admixture of Aedes aegypti mosquitoes: a precursor to successful worldwide colonization?

    PubMed

    Bennett, Kelly Louise; Shija, Fortunate; Linton, Yvonne-Marie; Misinzo, Gerald; Kaddumukasa, Martha; Djouaka, Rousseau; Anyaele, Okorie; Harris, Angela; Irish, Seth; Hlaing, Thaung; Prakash, Anil; Lutwama, Julius; Walton, Catherine

    2016-09-01

    Increasing globalization has promoted the spread of exotic species, including disease vectors. Understanding the evolutionary processes involved in such colonizations is both of intrinsic biological interest and important to predict and mitigate future disease risks. The Aedes aegypti mosquito is a major vector of dengue, chikungunya and Zika, the worldwide spread of which has been facilitated by Ae. aegypti's adaption to human-modified environments. Understanding the evolutionary processes involved in this invasion requires characterization of the genetic make-up of the source population(s). The application of approximate Bayesian computation (ABC) to sequence data from four nuclear and one mitochondrial marker revealed that African populations of Ae. aegypti best fit a demographic model of lineage diversification, historical admixture and recent population structuring. As ancestral Ae. aegypti were dependent on forests, this population history is consistent with the effects of forest fragmentation and expansion driven by Pleistocene climatic change. Alternatively, or additionally, historical human movement across the continent may have facilitated their recent spread and mixing. ABC analysis and haplotype networks support earlier inferences of a single out-of-Africa colonization event, while a cline of decreasing genetic diversity indicates that Ae. aegypti moved first from Africa to the Americas and then to Asia. ABC analysis was unable to verify this colonization route, possibly because the genetic signal of admixture obscures the true colonization pathway. By increasing genetic diversity and forming novel allelic combinations, divergence and historical admixture within Africa could have provided the adaptive potential needed for the successful worldwide spread of Ae. aegypti.

  16. On the Seasonal Occurrence and Abundance of the Zika Virus Vector Mosquito Aedes Aegypti in the Contiguous United States

    PubMed Central

    Monaghan, Andrew J.; Morin, Cory W.; Steinhoff, Daniel F.; Wilhelmi, Olga; Hayden, Mary; Quattrochi, Dale A.; Reiskind, Michael; Lloyd, Alun L.; Smith, Kirk; Schmidt, Chris A.; Scalf, Paige E.; Ernst, Kacey

    2016-01-01

    Introduction: An ongoing Zika virus pandemic in Latin America and the Caribbean has raised concerns that travel-related introduction of Zika virus could initiate local transmission in the United States (U.S.) by its primary vector, the mosquito Aedes aegypti. Methods: We employed meteorologically driven models for 2006-2015 to simulate the potential seasonal abundance of adult Aedes aegypti for fifty cities within or near the margins of its known U.S. range. Mosquito abundance results were analyzed alongside travel and socioeconomic factors that are proxies of viral introduction and vulnerability to human-vector contact.     Results: Meteorological conditions are largely unsuitable for Aedes aegypti over the U.S. during winter months (December-March), except in southern Florida and south Texas where comparatively warm conditions can sustain low-to-moderate potential mosquito abundance. Meteorological conditions are suitable for Aedes aegypti across all fifty cities during peak summer months (July-September), though the mosquito has not been documented in all cities. Simulations indicate the highest mosquito abundance occurs in the Southeast and south Texas where locally acquired cases of Aedes-transmitted viruses have been reported previously. Cities in southern Florida and south Texas are at the nexus of high seasonal suitability for Aedes aegypti and strong potential for travel-related virus introduction. Higher poverty rates in cities along the U.S.-Mexico border may correlate with factors that increase human exposure to Aedes aegypti.     Discussion: Our results can inform baseline risk for local Zika virus transmission in the U.S. and the optimal timing of vector control activities, and underscore the need for enhanced surveillance for Aedes mosquitoes and Aedes-transmitted viruses. PMID:27066299

  17. The Impact of Selection with Diflubenzuron, a Chitin Synthesis Inhibitor, on the Fitness of Two Brazilian Aedes aegypti Field Populations

    PubMed Central

    Belinato, Thiago Affonso; Valle, Denise

    2015-01-01

    Several Aedes aegypti field populations are resistant to neurotoxic insecticides, mainly organophoshates and pyrethroids, which are extensively used as larvicides and adulticides, respectively. Diflubenzuron (DFB), a chitin synthesis inhibitor (CSI), was recently approved for use in drinking water, and is presently employed in Brazil for Ae. aegypti control, against populations resistant to the organophosphate temephos. However, tests of DFB efficacy against field Ae. aegypti populations are lacking. In addition, information regarding the dynamics of CSI resistance, and characterization of any potential fitness effects that may arise in conjunction with resistance are essential for new Ae. aegypti control strategies. Here, the efficacy of DFB was evaluated for two Brazilian Ae. aegypti populations known to be resistant to both temephos and the pyrethroid deltamethrin. Laboratory selection for DFB resistance was then performed over six or seven generations, using a fixed dose of insecticide that inhibited 80% of adult emergence in the first generation. The selection process was stopped when adult emergence in the diflubenzuron-treated groups was equivalent to that of the control groups, kept without insecticide. Diflubenzuron was effective against the two Ae. aegypti field populations evaluated, regardless of their resistance level to neurotoxic insecticides. However, only a few generations of DFB selection were sufficient to change the susceptible status of both populations to this compound. Several aspects of mosquito biology were affected in both selected populations, indicating that diflubenzuron resistance acquisition is associated with a fitness cost. We believe that these results can significantly contribute to the design of control strategies involving the use of insect growth regulators. PMID:26107715

  18. Suppression of a Field Population of Aedes aegypti in Brazil by Sustained Release of Transgenic Male Mosquitoes.

    PubMed

    Carvalho, Danilo O; McKemey, Andrew R; Garziera, Luiza; Lacroix, Renaud; Donnelly, Christl A; Alphey, Luke; Malavasi, Aldo; Capurro, Margareth L

    2015-01-01

    The increasing burden of dengue, and the relative failure of traditional vector control programs highlight the need to develop new control methods. SIT using self-limiting genetic technology is one such promising method. A self-limiting strain of Aedes aegypti, OX513A, has already reached the stage of field evaluation. Sustained releases of OX513A Ae. aegypti males led to 80% suppression of a target wild Ae. aegypti population in the Cayman Islands in 2010. Here we describe sustained series of field releases of OX513A Ae. aegypti males in a suburb of Juazeiro, Bahia, Brazil. This study spanned over a year and reduced the local Ae. aegypti population by 95% (95% CI: 92.2%-97.5%) based on adult trap data and 81% (95% CI: 74.9-85.2%) based on ovitrap indices compared to the adjacent no-release control area. The mating competitiveness of the released males (0.031; 95% CI: 0.025-0.036) was similar to that estimated in the Cayman trials (0.059; 95% CI: 0.011-0.210), indicating that environmental and target-strain differences had little impact on the mating success of the OX513A males. We conclude that sustained release of OX513A males may be an effective and widely useful method for suppression of the key dengue vector Ae. aegypti. The observed level of suppression would likely be sufficient to prevent dengue epidemics in the locality tested and other areas with similar or lower transmission.

  19. The Impact of Selection with Diflubenzuron, a Chitin Synthesis Inhibitor, on the Fitness of Two Brazilian Aedes aegypti Field Populations.

    PubMed

    Belinato, Thiago Affonso; Valle, Denise

    2015-01-01

    Several Aedes aegypti field populations are resistant to neurotoxic insecticides, mainly organophoshates and pyrethroids, which are extensively used as larvicides and adulticides, respectively. Diflubenzuron (DFB), a chitin synthesis inhibitor (CSI), was recently approved for use in drinking water, and is presently employed in Brazil for Ae. aegypti control, against populations resistant to the organophosphate temephos. However, tests of DFB efficacy against field Ae. aegypti populations are lacking. In addition, information regarding the dynamics of CSI resistance, and characterization of any potential fitness effects that may arise in conjunction with resistance are essential for new Ae. aegypti control strategies. Here, the efficacy of DFB was evaluated for two Brazilian Ae. aegypti populations known to be resistant to both temephos and the pyrethroid deltamethrin. Laboratory selection for DFB resistance was then performed over six or seven generations, using a fixed dose of insecticide that inhibited 80% of adult emergence in the first generation. The selection process was stopped when adult emergence in the diflubenzuron-treated groups was equivalent to that of the control groups, kept without insecticide. Diflubenzuron was effective against the two Ae. aegypti field populations evaluated, regardless of their resistance level to neurotoxic insecticides. However, only a few generations of DFB selection were sufficient to change the susceptible status of both populations to this compound. Several aspects of mosquito biology were affected in both selected populations, indicating that diflubenzuron resistance acquisition is associated with a fitness cost. We believe that these results can significantly contribute to the design of control strategies involving the use of insect growth regulators.

  20. Reported Distribution of Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus in the United States, 1995-2016 (Diptera: Culicidae).

    PubMed

    Hahn, Micah B; Eisen, Rebecca J; Eisen, Lars; Boegler, Karen A; Moore, Chester G; McAllister, Janet; Savage, Harry M; Mutebi, John-Paul

    2016-06-09

    Aedes (Stegomyia) aegypti (L.) and Aedes (Stegomyia) albopictus (Skuse) transmit arboviruses that are increasing threats to human health in the Americas, particularly dengue, chikungunya, and Zika viruses. Epidemics of the associated arboviral diseases have been limited to South and Central America, Mexico, and the Caribbean in the Western Hemisphere, with only minor localized outbreaks in the United States. Nevertheless, accurate and up-to-date information for the geographical ranges of Ae. aegypti and Ae. albopictus in the United States is urgently needed to guide surveillance and enhance control capacity for these mosquitoes. We compiled county records for presence of Ae. aegypti and Ae. albopictus in the United States from 1995-2016, presented here in map format. Records were derived from the Centers for Disease Control and Prevention ArboNET database, VectorMap, the published literature, and a survey of mosquito control agencies, university researchers, and state and local health departments. Between January 1995 and March 2016, 183 counties from 26 states and the District of Columbia reported occurrence of Ae. aegypti, and 1,241 counties from 40 states and the District of Columbia reported occurrence of Ae. albopictus During the same time period, Ae. aegypti was collected in 3 or more years from 94 counties from 14 states and the District of Columbia, and Ae. albopictus was collected during 3 or more years from 514 counties in 34 states and the District of Columbia. Our findings underscore the need for systematic surveillance of Ae. aegypti and Ae. albopictus in the United States and delineate areas with risk for the transmission of these introduced arboviruses.

  1. Suppression of a Field Population of Aedes aegypti in Brazil by Sustained Release of Transgenic Male Mosquitoes

    PubMed Central

    Garziera, Luiza; Lacroix, Renaud; Donnelly, Christl A.; Alphey, Luke; Malavasi, Aldo; Capurro, Margareth L.

    2015-01-01

    The increasing burden of dengue, and the relative failure of traditional vector control programs highlight the need to develop new control methods. SIT using self-limiting genetic technology is one such promising method. A self-limiting strain of Aedes aegypti, OX513A, has already reached the stage of field evaluation. Sustained releases of OX513A Ae. aegypti males led to 80% suppression of a target wild Ae. aegypti population in the Cayman Islands in 2010. Here we describe sustained series of field releases of OX513A Ae. aegypti males in a suburb of Juazeiro, Bahia, Brazil. This study spanned over a year and reduced the local Ae. aegypti population by 95% (95% CI: 92.2%-97.5%) based on adult trap data and 81% (95% CI: 74.9-85.2%) based on ovitrap indices compared to the adjacent no-release control area. The mating competitiveness of the released males (0.031; 95% CI: 0.025-0.036) was similar to that estimated in the Cayman trials (0.059; 95% CI: 0.011 – 0.210), indicating that environmental and target-strain differences had little impact on the mating success of the OX513A males. We conclude that sustained release of OX513A males may be an effective and widely useful method for suppression of the key dengue vector Ae. aegypti. The observed level of suppression would likely be sufficient to prevent dengue epidemics in the locality tested and other areas with similar or lower transmission. PMID:26135160

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

    PubMed

    Oliveira, Viviane Camila de; Almeida, Luiz Carlos de

    2017-01-23

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

  3. Behavioral responses of catnip (Nepeta cataria) by two species of mosquitoes, Aedes aegypti and Anopheles harrisoni, in Thailand.

    PubMed

    Polsomboon, Suppaluck; Grieco, John P; Achee, Nicole L; Chauhan, Kamlesh R; Tanasinchayakul, Somchai; Pothikasikorn, Jinrapa; Chareonviriyaphap, Theeraphap

    2008-12-01

    An investigation of the biological effect of catnip oil (Nepeta cataria L.) on the behavioral response of field collected Aedes aegypti and Anopheles harrisoni was conducted using an automated excitorepellency test system. Aedes aegypti showed significantly higher escape rates from the contact chamber at 5% catnip oil compared to other concentrations (P < 0.05). With Anopheles harrisoni, a high escape response was seen at 2.5% catnip oil from the contact chamber, while in the noncontact chamber a higher escape response was observed at a concentration of 5%. Results showed that this compound exhibits both irritant and repellent actions.

  4. The Con Test

    ERIC Educational Resources Information Center

    Fletcher, Michael

    2009-01-01

    In this article, the author describes the format of the Con Test, an Australian television game show which followed the same general rules and game play as the UK show PokerFace. At the end of each round a contestant needs to decide whether or not he or she should fold. A contestant needs to know how likely it is that he or she is in last place.…

  5. Diffusion of community empowerment strategies for Aedes aegypti control in Cuba: a muddling through experience.

    PubMed

    Pérez, Dennis; Lefèvre, Pierre; Castro, Marta; Toledo, María Eugenia; Zamora, Gilberto; Bonet, Mariano; Van der Stuyft, Patrick

    2013-05-01

    Effective participatory strategies in dengue control have been developed and assessed as small-scale efforts. The challenge is to scale-up and institutionalize these strategies within dengue control programs. We describe and critically analyze the diffusion process of an effective empowerment strategy within the Cuban Aedes aegypti control program, focusing on decision-making at the national level, to identify ways forward to institutionalize such strategies in Cuba and elsewhere. From 2005 to 2009, we carried out a process-oriented case study. We used participant observation, in-depth interviews with key informants involved in the diffusion process and document analysis. In a first phase, the data analysis was inductive. In a second phase, to enhance robustness of the analysis, emerging categories were contrasted with Rogers' five-stage conceptual model of the innovation-decision process, which was eventually used as the analytical framework. The diffusion of the empowerment strategy was a continuous and dynamic process. Adoption was a result of the perceived potential match between the innovative empowerment strategy and the performance gap of the Ae. aegypti control program. During implementation, the strategy was partially modified by top level Ae. aegypti control program decision-makers to accommodate program characteristics. However, structure, practices and organizational culture of the control program did not change significantly. Thus rejection occurred. It was mainly due to insufficient dissemination of know-how and underlying principles of the strategy by innovation developers, but also to resistance to change. The innovation-diffusion process has produced mitigated results to date, and the control program is still struggling to find ways to move forward. Improving the innovation strategy by providing the necessary knowledge about the innovation and addressing control program organizational changes is crucial for successful diffusion of empowerment

  6. Climate change and the potential global distribution of Aedes aegypti: spatial modelling using GIS and CLIMEX.

    PubMed

    Khormi, Hassan M; Kumar, Lalit

    2014-05-01

    We examined the potential added risk posed by global climate change on the dengue vector Aedes aegypti abundance using CLIMEX, a powerful tool for exploring the relationship between the fundamental and realised niche of any species. After calibrating the model using data from several knowledge domains, including geographical distribution records, we estimated potential distributions of the mosquito under current and future potential scenarios. The impact of climate change on its potential distribution was assessed with two global climate models, the CSIRO-Mk3.0 and the MIROC-H, run with two potential, future emission scenarios (A1B and A2) published by the Intergovernmental Panel on Climate Change. We compared today's climate situation with two arbitrarily chosen future time points (2030 and 2070) to see the impact on the worldwide distribution of A. aegypti . The model for the current global climate indicated favourable areas for the mosquito within its known distribution in tropical and subtropical areas. However, even if much of the tropics and subtropics will continue to be suitable, the climatically favourable areas for A. aegypti globally are projected to contract under the future scenarios produced by these models, while currently unfavourable areas, such as inland Australia, the Arabian Peninsula, southern Iran and some parts of North America may become climatically favourable for this mosquito species. The climate models for the Aedes dengue vector presented here should be useful for management purposes as they can be adapted for decision/making regarding allocation of resources for dengue risk toward areas where risk infection remains and away from areas where climatic suitability is likely to decrease in the future.

  7. Effects of different temperature regimens on the development of Aedes aegypti (L.) (Diptera: Culicidae) mosquitoes.

    PubMed

    Mohammed, Azad; Chadee, Dave D

    2011-07-01

    This study was conducted to determine the effects of increased water temperatures on the development of Aedes aegypti immatures under laboratory conditions in Trinidad, West Indies using temperature regulated water baths to cover a range of temperatures from 24-25°C to 34-35°C at a relative humidity of 80%. Two experiments were designed: (1) at constant temperature regimens and (2) under diurnal temperature regimens ranging from 24-25°C to 34-35°C. At 24-25°C egg hatching success was 98% at 48 h, however at 34-35°C egg hatching rates declined to 1.6% after 48 h. Ae. aegypti larvae reared under constant temperature regimens showed pupation on day 4 with highest pupation occurring at 30°C (78.4%) However, under diurnal temperature regimens, pupation began on day 4 but only at the higher temperatures of 30-35°C. Under diurnal temperature regimens ranging from 24°C to 35°C significantly more females emerged at higher temperatures, than males. In contrast, at constant temperatures of 24-35°C no significant difference in M/F ratios were observed. The body size of Ae. aegypti reared at constant temperature regimens was significantly larger than males and females larvae reared under diurnal temperature regimens of 25-30°C. The results of this study are discussed in the context of changing or increasing water temperatures, seasonal changes in vector populations and vector competence. Using these key factors control strategies are recommended to manage vector populations as expected increases in temperatures impact the Caribbean region.

  8. Oviposition and flight orientation response of Aedes aegypti to certain aromatic aryl hydrazono esters.

    PubMed

    Guha, Lopamudra; Seenivasagan, T; Bandyopadhyay, Prabal; Iqbal, S Thanvir; Sathe, Manisha; Sharma, Pratibha; Parashar, B D; Kaushik, M P

    2012-09-01

    Aedes aegypti is a day-biting, highly anthropophilic mosquito and a potential vector of dengue and chikungunya in India. A. aegypti is a container breeder, generally oviposit in the stored and fresh water bodies, and discarded containers near residential areas that provide suitable habitats for oviposition by gravid females. The diurnal activity and endophilic nature of these mosquitoes have increased the frequency of contact with human being. Assured blood meal from human host in an infested area leads to increased disease occurrence. Gravid mosquitoes can potentially be lured to attractant-treated traps and could subsequently be killed with insecticides or growth regulators. In this direction, oviposition by A. aegypti females to aryl hydrazono esters (AHE)-treated bowls at 10 ppm concentration was tested in dual choice experiment, and their orientation response to these ester compounds was studied in Y-tube olfactometer. Among the esters tested, AHE-2, AHE-11 and AHE-12 elicited increased egg deposition with oviposition activity indices (OAI) of +0.39, +0.24 and +0.48, respectively, compared to control; in contrast, AHE-8, AHE-9 and AHE-10 showed negative oviposition response with OAI of -0.46, -0.35 and -0.29, respectively, at 10 mg/L. In the Y-tube olfactometer bioassay, AHE-2 attracted 60 % females compared to control, while to the odour of AHE-11 and AHE-12, about 70 % of the females were trapped in treated chambers. In contrast, only 27-30 % of gravid females entered the chamber releasing AHE-8, AHE-9 and AHE-10 odour plumes, while 70 % entered control chamber, evincing a possible non-preference of treatment odours as well as interference with olfactory receptors. These compounds have the potential for application as oviposition stimulants or deterrents for surveillance and control of mosquito population using ovitraps.

  9. Biochemical evidence of efficacy of potash alum for the control of dengue vector Aedes aegypti (Linnaeus).

    PubMed

    Preet, Shabad; Sneha, A

    2011-06-01

    Aedes aegypti is the primary vector of dengue, yellow fever and chikungunya in India and other South East Asian countries, and novel insecticides for vector control are urgently needed. In the present investigation, efficacy of potash alum, a traditionally known double salt in Indian and Chinese medicine system, was tested against the larvae of dengue vector, A. aegypti. LC(50,) LC(90) and LC(99) values were recorded for various instar larvae where I instar larvae were found to be the most susceptible and IV instar larvae as the least susceptible one. The LC(50) values of crude and standard potash alum of various instar larvae ranged between 15.29 and 48.53 ppm and 20.50-65.10 ppm, respectively. Biochemical changes were also evidenced in IV instar A. aegypti larvae following a sublethal exposure for 24 h in the levels of various nutrient reserves and primary metabolites such as sugar, glycogen, lipids and proteins suggesting possible mode of action responsible for larval mortality. Sugar and glycogen concentrations were measured as 24.6 and 10.67 μg per five larvae in controls which were significantly (p<0.05) reduced by 32.11-93.98% and 39.26-94.47%, respectively, in larvae treated with crude alum. In controls, protein and lipid content were recorded as 210.74 and 94.71 μg per five larvae which dropped up to 26.53% and 25.5%, respectively, in larvae following treatment with crude alum. Moreover, drastic changes were also recorded for DNA content with 25.39-44.17% decrease in crude alum-treated larvae. It is evident from these results that potash alum, a fairly cheaper and readily available ecofriendly compound could be recommended as a potential chemical larvicide against dengue vector at mosquito breeding sites in the vicinity of human dwellings.

  10. Surveillance, insecticide resistance and control of an invasive Aedes aegypti (Diptera: Culicidae) population in California

    PubMed Central

    Cornel, Anthony J.; Holeman, Jodi; Nieman, Catelyn C.; Lee, Yoosook; Smith, Charles; Amorino, Mark; Brisco, Katherine K.; Barrera, Roberto; Lanzaro, Gregory C.; Mulligan III, F. Stephen

    2016-01-01

    The invasion and subsequent establishment in California of Aedes aegypti in 2013 has created new challenges for local mosquito abatement and vector control districts. Studies were undertaken to identify effective and economical strategies to monitor the abundance and spread of this mosquito species as well as for its control. Overall, BG Sentinel (BGS) traps were found to be the most sensitive trap type to measure abundance and spread into new locations. Autocidal-Gravid-Ovitraps (AGO-B), when placed at a site for a week, performed equally to BGS in detecting the presence of female Ae. aegypti. Considering operational cost and our findings, we recommend use of BGS traps for surveillance in response to service requests especially in locations outside the known infestation area. We recommend AGO-Bs be placed at fixed sites, cleared and processed once a week to monitor mosquito abundance within a known infestation area. Long-term high density placements of AGO-Bs were found to show promise as an environmentally friendly trap-kill control strategy. California Ae. aegypti were found to be homozygous for the V1016I mutation in the voltage gated sodium channel gene, which is implicated to be involved in insecticide resistance. This strain originating from Clovis, California was resistant to some pyrethroids but not to deltamethrin in bottle bio-assays. Sentinel cage ultra-low-volume (ULV) trials using a new formulation of deltamethrin (DeltaGard®) demonstrated that it provided some control (average of 56% death in sentinel cages in a 91.4 m spray swath) after a single truck mounted aerial ULV application in residential areas. PMID:27158450

  11. Use of transgenic Aedes aegypti in Brazil: risk perception and assessment

    PubMed Central

    Aragão, Francisco José Lima; Colli, Walter; Dellagostin, Odir Antônio; Finardi-Filho, Flávio; Hirata, Mario Hiroyuki; Lira-Neto, Amaro de Castro; Almeida de Melo, Marcia; Nepomuceno, Alexandre Lima; Gorgônio da Nóbrega, Francisco; Delfino de Sousa, Gutemberg; Valicente, Fernando Hercos; Zanettini, Maria Helena Bodanese

    2016-01-01

    Abstract The OX513A strain of Aedes aegypti, which was developed by the British company Oxitec, expresses a self-limiting transgene that prevents larvae from developing to adulthood. In April 2014, the Brazilian National Technical Commission on Biosafety completed a risk assessment of OX513A and concluded that the strain did not present new biological risks to humans or the environment and could be released in Brazil. At that point, Brazil became the first country to approve the unconstrained release of a genetically modified mosquito. During the assessment, the commission produced a comprehensive list of – and systematically analysed – the perceived hazards. Such hazards included the potential survival to adulthood of immature stages carrying the transgene – should the transgene fail to be expressed or be turned off by exposure to sufficient environmental tetracycline. Other perceived hazards included the potential allergenicity and/or toxicity of the proteins expressed by the gene, the potential for gene flow or increased transmission of human pathogens and the occupation of vacant breeding sites by other vector species. The Zika epidemic both elevated the perceived importance of Ae. aegypti as a vector – among policy-makers and regulators as well as the general public – and increased concerns over the release of males of the OX513A strain. We have therefore reassessed the potential hazards. We found that release of the transgenic mosquitoes would still be both safe and of great potential value in the control of diseases spread by Ae. aegypti, such as chikungunya, dengue and Zika. PMID:27843167

  12. Laboratory strains of Aedes aegypti are competent to Brazilian Zika virus.

    PubMed

    Costa-da-Silva, André Luis; Ioshino, Rafaella Sayuri; Araújo, Helena Rocha Corrêa de; Kojin, Bianca Burini; Zanotto, Paolo Marinho de Andrade; Oliveira, Danielle Bruna Leal; Melo, Stella Rezende; Durigon, Edison Luiz; Capurro, Margareth Lara

    2017-01-01

    The Zika virus outbreaks are unprecedented human threat in relation to congenital malformations and neurological/autoimmune complications. Since this virus has high potential to spread in regions presenting the vectors, improvement in mosquito control is a top priority. Thus, Aedes aegypti laboratory strains will be fundamental to support studies in different research fields implicated on Zika-mosquito interactions which are the basis for the development of innovative control methods. In this sense, our aim was to determine the main infection aspects of a Brazilian Zika strain in reference Aedes aegypti laboratory mosquitoes. We orally exposed Rockefeller, Higgs and Rexville mosquitoes to the Brazilian ZIKV (ZIKVBR) and qRT-PCR was applied to determine the infection, dissemination and detection rates of ZIKV in the collected saliva as well as viral levels in mosquito tissues. The three strains sustain the virus development but Higgs showed significantly lower viral loads in bodies at 14 days post-infection (dpi) and the lowest prevalences in bodies and heads. The Rockefeller strain was the most susceptible at 7 dpi but similar dissemination rates were observed at 14 dpi. Although variations exist, the ZIKVBR RNA shows detectable levels in saliva of the three strains at 14 dpi but is only detected in Rockefeller at 7 dpi. Moreover, saliva samples from the three strains were confirmed to be infectious when intrathoracically injected into mosquitoes. The ZIKVBR kinetics was monitored in Rockefeller mosquitoes and virus could be identified in the heads at 4 dpi but was more consistently detected late in infection. Our study presents the first evaluation on how Brazilian Zika virus behaves in reference Aedes aegypti strains and shed light on how the infection evolves over time. Vector competence and hallmarks of the ZIKVBR development were revealed in laboratory mosquitoes, providing additional information to accelerate studies focused on ZIKV-mosquito interactions.

  13. Larvicidal and Growth-Inhibitory Activity of Entomopathogenic Bacteria Culture Fluids Against Aedes aegypti (Diptera: Culicidae).

    PubMed

    da Silva, João Luiz Rosa; Undurraga Schwalm, Fernanda; Eugênio Silva, Carlos; da Costa, Marisa; Heermann, Ralf; Santos da Silva, Onilda

    2017-01-06

    Dengue, Chikungunya, and Zika are important vector-borne diseases, and Aedes aegypti L. is their main transmitter. As the disease management is mainly based on mosquito control strategies, the search for alternative and cost-effective approaches is ongoing. The Gram-negative bacteria Xenorhabdus nematophila and Photorhabdus luminescens are symbiotically associated with entomopathogenic nematodes and are highly pathogenic for insect larvae. After we have recently confirmed the toxicity of these bacteria in Ae. aegypti larvae, we here evaluated the toxic activity of culture fluids on the development of this mosquito species. Larval susceptibility was assessed by exposing larvae to different concentrations of P. luminescens or X. nematophila culture fluids to confirm whether secondary metabolites might cause the mosquitos' death. Xenorhabdus nematophila culture fluid was more effective and stable during the mosquito pathogenicity bioassays compared to that of P. luminescens Larval mortality started a few hours after exposure of the insects to the fluids. Furthermore, the residual effect of larvicidal activity of X. nematophila fluid persisted at full efficiency for 4 d. Particularly, larval mortality was still higher than 50% for up to 8 d. Exposure of larvae to a sublethal dose of X. nematophila fluid delayed pupation as well as emergence of adult mosquitoes and caused cumulative larval mortality higher than 90% by day 14. Here, we describe for the first time the use of stable culture fluids and therefore secondary metabolites of P. luminescens and X. nematophila as a promising basis for the use as biopesticide for control of Ae. aegypti in the future.

  14. Rainfall, abundance of Aedes aegypti and dengue infection in Selangor, Malaysia.

    PubMed

    Li, C F; Lim, T W; Han, L L; Fang, R

    1985-12-01

    An epidemio-meteorotropic analytical study of Selangor, in the Southwest coast of Peninsular Malaysia, examines the monthly incidence of dengue for the period 1973-1982 to assess possible quantitative association with the monthly rainfall. The relationships between rainfall, abundance of A. aegypti and dengue infection during 1982 in Jinjang, a dengue-prone area in Selangor, were also examined. A quantitative association between rainfall and the number of dengue cases was found during the first wet period. The lag time between the onset of heavy rain and dengue outbreak was about two to three months. A 120% increase in the number of dengue cases was observed when the monthly rainfall was 300 mm or more. Positive associations were seen between the incidence of dengue and the Aedes house index and the Breteau index in Jinjang. The relationships between these three variables and rainfall suggest that the latter might have exerted its effect on dengue infection partly through the creation of more breeding sites for A. aegypti. Assessment of the importance of A. aegypti in the transmission of dengue in this locality was not possible because of the lack of adjustment for A. albopictus, the other known vector of dengue in the state, and for social and other environmental factors influencing infection rates. In spite of this and the interpretational problems common in aggregate studies, the present analyses have provided relatively strong statistical evidence of an association between rainfall and dengue outbreaks in Selangor, thereby indicating that it is a factor worthy of careful surveillance and monitoring.

  15. Undesirable Consequences of Insecticide Resistance following Aedes aegypti Control Activities Due to a Dengue Outbreak

    PubMed Central

    Maciel-de-Freitas, Rafael; Avendanho, Fernando Campos; Santos, Rosangela; Sylvestre, Gabriel; Araújo, Simone Costa; Lima, José Bento Pereira; Martins, Ademir Jesus; Coelho, Giovanini Evelim; Valle, Denise

    2014-01-01

    Background During a dengue outbreak with co-circulation of DENV-1 and -2 in the city of Boa Vista, one patient was diagnosed with DENV-4, a serotype supposed absent from Brazil for almost 30 years. The re-emergence of DENV-4 triggered the intensification of mechanical and chemical Aedes aegypti control activities in order to reduce vector density and avoid DENV-4 dissemination throughout the country. Methods/Principal Findings Vector control activities consisted of (a) source reduction, (b) application of diflubenzuron against larvae and (c) vehicle-mounted space spraying of 2% deltamethrin to eliminate adults. Control activity efficacy was monitored by comparing the infestation levels and the number of eggs collected in ovitraps before and after interventions, performed in 22 Boa Vista districts, covering an area of ∼80% of the city and encompassing 56,837 dwellings. A total of 94,325 containers were eliminated or treated with diflubenzuron. The most frequently positive containers were small miscellaneous receptacles, which corresponded to 59% of all positive breeding sites. Insecticide resistance to deltamethrin was assessed before, during and after interventions by dose-response bioassays adopting WHO-based protocols. The intense use of the pyrethroid increased fourfold the resistance ratio of the local Ae. aegypti population only six months after the beginning of vector control. Curiously, this trend was also observed in the districts in which no deltamethrin was applied by the public health services. On the other hand, changes in the resistance ratio to the organophosphate temephos seemed less influenced by insecticide in Boa Vista. Conclusions Despite the intense effort, mosquito infestation levels were only slightly reduced. Besides, the median number of eggs in ovitraps remained unaltered after control activity intensification. The great and rapid increase in pyrethroid resistance levels of natural Ae. aegypti populations is discussed in the context of

  16. Transstadial Effects of Bti on Traits of Aedes aegypti and Infection with Dengue Virus

    PubMed Central

    Alto, Barry W.; Lord, Cynthia C.

    2016-01-01

    Most mosquito control efforts are primarily focused on reducing the adult population size mediated by reductions in the larval population, which should lower risk of disease transmission. Although the aim of larviciding is to reduce larval abundance and thus recruitment of adults, nonlethal effects on adults are possible, including transstadial effects on phenotypes of adults such as survival and pathogen infection and transmission. In addition, the mortality induced by control efforts may act in conjunction with other sources of mosquito mortality in nature. The consequences of these effects and interactions may alter the potential of the population to transmit pathogens. We tested experimentally the combined effects of a larvicide (Bacillus thuringiensis ssp. israelensis, Bti) and competition during the larval stages on subsequent Aedes aegypti (Linnaeus) traits, population performance, and susceptibility to dengue-1 virus infection. Ae. aegypti that survived exposure to Bti experienced accelerated development, were larger, and produced more eggs with increasing amounts of Bti, consistent with competitive release among surviving mosquitoes. Changing larval density had no significant interactive effect with Bti treatment on development and growth to adulthood. Larval density, but not Bti or treatment interaction, had a strong effect on survival of adult Ae. aegypti females. There were sharper declines in cumulative daily survival of adults from crowded than uncrowded larval conditions, suggesting that high competition conditions of larvae may be an impediment to transmission of dengue viruses. Rates of infection and dengue-1 virus disseminated infections were found to be 87±13% and 88±12%, respectively. There were no significant treatment effects on infection measurements. Our findings suggest that larvicide campaigns using Bti may reduce the number of emerged adults, but survivors will have a fitness advantage (growth, development, enhanced production of eggs

  17. Electroantennogram, flight orientation, and oviposition responses of Aedes aegypti to the oviposition pheromone n-heneicosane.

    PubMed

    Seenivasagan, T; Sharma, Kavita R; Sekhar, K; Ganesan, K; Prakash, Shri; Vijayaraghavan, R

    2009-03-01

    Oviposition pheromones specifically influence the females of many insects to lay eggs in the sites resulting in more egg deposition. A previous report describes the principal role of n-heneicosane (C(21)) identified and characterized from the larval cuticle of Aedes aegypti (L.) in attracting the gravid mosquitoes to oviposit in treated substrates among other chemical components. However, the means by which this compound is perceived by the females for oviposition has not been reported. In this study, we have recorded the peripheral olfactory responses from the antenna of Ae. aegypti from 10(-7) g to 10(-3) g doses of n-heneicosane. The EAG response of female mosquitoes increased in a dose-dependent manner with increasing stimulus strength. In the orientation assay using Y-maze olfactometer, female mosquitoes were attracted to the odor plume of 10(-6) g and 10(-5) g dose, while the higher dose of 10(-3) g plume enforced repellency to gravid mosquitoes. The response to oviposition substrates by gravid Ae. aegypti females differed across the range of concentrations of n-heneicosane under multiple choice conditions, larger number of eggs were deposited in 10 ppm (10 mg/l) solutions compared to lower and higher concentrations indicating 10 ppm was most attractive. Application of n-heneicosane at 10 ppm in breeding habitats will be a useful method to attract the gravid mosquitoes using ovitraps for surveillance and monitoring. The possible use of this compound in monitoring of mosquito population in endemic areas in relevance to integrated vector management strategies is discussed in detail.

  18. Determinants of Heterogeneous Blood Feeding Patterns by Aedes aegypti in Iquitos, Peru

    PubMed Central

    Liebman, Kelly A.; Stoddard, Steven T.; Reiner, Robert C.; Perkins, T. Alex; Astete, Helvio; Sihuincha, Moises; Halsey, Eric S.; Kochel, Tadeusz J.; Morrison, Amy C.; Scott, Thomas W.

    2014-01-01

    Background Heterogeneous mosquito biting results in different individuals in a population receiving an uneven number of bites. This is a feature of many vector-borne disease systems that, if understood, could guide preventative control efforts toward individuals who are expected to contribute most to pathogen transmission. We aimed to characterize factors determining biting patterns of Aedes aegypti, the principal mosquito vector of dengue virus. Methodology/Principal Findings Engorged female Ae. aegypti and human cheek swabs were collected from 19 houses in Iquitos, Peru. We recorded the body size, age, and sex of 275 consenting residents. Movement in and out of the house over a week (time in house) and mosquito abundance were recorded on eight separate occasions in each household over twelve months. We identified the individuals bitten by 96 engorged mosquitoes over this period by amplifying specific human microsatellite markers in mosquito blood meals and human cheek swabs. Using a multinomial model assuming a saturating relationship (power), we found that, relative to other residents of a home, an individual's likelihood of being bitten in the home was directly proportional to time spent in their home and body surface area (p<0.05). A linear function fit the relationship equally well (ΔAIC<1). Conclusions/Significance Our results indicate that larger people and those who spend more time at home are more likely to receive Ae. aegypti bites in their homes than other household residents. These findings are consistent with the idea that measurable characteristics of individuals can inform predictions of the extent to which different people will be bitten. This has implications for an improved understanding of heterogeneity in different people's contributions to pathogen transmission, and enhanced interventions that include the people and places that contribute most to pathogen amplification and spread. PMID:24551262

  19. Physiological and Morphological Aspects of Aedes aegypti Developing Larvae: Effects of the Chitin Synthesis Inhibitor Novaluron

    PubMed Central

    Farnesi, Luana C.; Brito, José M.; Linss, Jutta G.; Pelajo-Machado, Marcelo; Valle, Denise; Rezende, Gustavo L.

    2012-01-01

    Population control of the dengue vector mosquito, Aedes aegypti, is difficult due to many reasons, one being the development of resistance to neurotoxic insecticides employed. The biosynthesis of chitin, a major constituent of insect cuticle, is a novel target for population control. Novaluron is a benzoylphenylurea (BPU) that acts as a chitin synthesis inhibitor, already used against mosquitoes. However, information regarding BPU effects on immature mosquito stages and physiological parameters related with mosquito larval development are scarce. A set of physiological parameters were recorded in control developing larvae and novaluron was administered continuously to Ae. aegypti larvae, since early third instar. Larval instar period duration was recorded from third instar until pupation. Chitin content was measured during third and fourth instars. Fourth instars were processed histochemically at the mesothorax region, stained with hematoxylin and eosin (HE) for assessment of internal tissues, and labeled with WGA-FITC to reveal chitinized structures. In control larvae: i) there is a chitin content increase during both third and fourth instars where late third instars contain more chitin than early fourth instars; ii) thoracic organs and a continuous cuticle, closely associated with the underlying epidermis were observed; iii) chitin was continuously present throughout integument cuticle. Novaluron treatment inhibited adult emergence, induced immature mortality, altered adult sex ratio and caused delay in larval development. Moreover, novaluron: i) significantly affected chitin content during larval development; ii) induced a discontinuous and altered cuticle in some regions while epidermis was often thinner or missing; iii) rendered chitin cuticle presence discontinuous and less evident. In both control and novaluron larvae, chitin was present in the peritrophic matrix. This study showed quantitatively and qualitatively evidences of novaluron effects on Ae

  20. Community-based control of Aedes aegypti by using Mesocyclops in southern Vietnam.

    PubMed

    Sinh Nam, Vu; Thi Yen, Nguyen; Minh Duc, Hoang; Cong Tu, Tran; Trong Thang, Vu; Hoang Le, Nguyen; Hoang San, Le; Le Loan, Luu; Que Huong, Vu Thi; Kim Khanh, Ly Huynh; Thuy Trang, Huynh Thi; Lam, Leonie Z Y; Kutcher, Simon C; Aaskov, John G; Jeffery, Jason A L; Ryan, Peter A; Kay, Brian H

    2012-05-01

    We previously reported a new community-based mosquito control strategy that resulted in elimination of Aedes aegypti (Linn.) in 40 of 46 communes in northern and central Vietnam, and with annual recurrent total costs (direct and indirect) of only $0.28-$0.89 international dollars per person. This control strategy was extended to four provinces in southern Vietnam in Long An and Hau Giang (2004-2007) and to Long An, Ben Tre, and Vinh Long (2005-2010). In a total of 14 communes with 124,743 residents, the mean ± SD of adult female Ae. aegypti was reduced from 0.93 ± 0.62 to 0.06 ± 0.09, and the reduction of immature Ae. aegypti averaged 98.8%. By the final survey, no adults could be collected in 6 of 14 communes, and one commune, Binh Thanh, also had no immature forms. Although the community-based programs also involved community education and clean-up campaigns, the prevalence of Mesocyclops in large water storage containers > 50 liters increased from 12.77 ± 8.39 to 75.69 ± 9.17% over periods of 15-45 months. At the conclusion of the study, no confirmed dengue cases were detected in four of the five communes for which diagnostic serologic analysis was performed. The rate of progress was faster in communes that were added in stages to the program but the reason for this finding was unclear. At the completion of the formal project, sustainability funds were set up to provide each commune with the financial means to ensure that community-based dengue control activities continued.

  1. Prevention of dengue outbreaks through Aedes aegypti oviposition activity forecasting method.

    PubMed

    Estallo, Elizabet L; Ludueña-Almeida, Francisco F; Visintin, Andrés M; Scavuzzo, Carlos M; Introini, María V; Zaidenberg, Mario; Almirón, Walter R

    2011-05-01

    Dengue has affected the north provinces of Argentina, mainly Salta province. The 2009 outbreak, with 5 deaths and >27,000 infected, was the most important, and the first to extend into the central area of the country. This article includes research on seasonal Aedes aegypti abundance variation in Orán City (Salta province), and determination of the date of mosquito population increase and an estimation of the date of maximum rate of increase as well as the intrinsic rate of natural increase (r), to detect the optimal time to apply vector control measures. Between September 2005 and March 2007, ovitraps were randomly distributed in the city to collect Ae. aegypti eggs. The variation observed in the number of collected eggs was described by fitting a third-degree polynomial by the least square method, allowing to determine the time when population increase began (week 1), after the temperate and dry season. Eggs were collected throughout the year, with the highest variation in abundance during the warm and rainy season, and the maximum value registered in February 2007. The rate of increase of the number of eggs laid per week peaked between weeks 9 and 10 after the beginning of the population increase (week 1). Week 1 depends on temperature, it occurs after getting over the thermal threshold and the needed accumulation of 160 degree-day is reached. Consequently, week 1 changes depending on temperature. Peak abundance of eggs during 2005-2006 was recorded on week 15 (after week 1); during 2006-2007, the peak was observed on week 22. Estimation of the intrinsic rate of natural increase (r) of Ae. aegypti is useful not only to determine optimal time to apply vector control measures with better cost-benefit, but also to add an insecticide control strategy against the vector to diminish the possibility of resistance.

  2. Surveillance, insecticide resistance and control of an invasive Aedes aegypti (Diptera: Culicidae) population in California.

    PubMed

    Cornel, Anthony J; Holeman, Jodi; Nieman, Catelyn C; Lee, Yoosook; Smith, Charles; Amorino, Mark; Brisco, Katherine K; Barrera, Roberto; Lanzaro, Gregory C; Mulligan Iii, F Stephen

    2016-01-01

    The invasion and subsequent establishment in California of Aedes aegypti in 2013 has created new challenges for local mosquito abatement and vector control districts. Studies were undertaken to identify effective and economical strategies to monitor the abundance and spread of this mosquito species as well as for its control. Overall, BG Sentinel (BGS) traps were found to be the most sensitive trap type to measure abundance and spread into new locations. Autocidal-Gravid-Ovitraps (AGO-B), when placed at a site for a week, performed equally to BGS in detecting the presence of female Ae. aegypti. Considering operational cost and our findings, we recommend use of BGS traps for surveillance in response to service requests especially in locations outside the known infestation area. We recommend AGO-Bs be placed at fixed sites, cleared and processed once a week to monitor mosquito abundance within a known infestation area. Long-term high density placements of AGO-Bs were found to show promise as an environmentally friendly trap-kill control strategy. California Ae. aegypti were found to be homozygous for the V1016I mutation in the voltage gated sodium channel gene, which is implicated to be involved in insecticide resistance. This strain originating from Clovis, California was resistant to some pyrethroids but not to deltamethrin in bottle bio-assays. Sentinel cage ultra-low-volume (ULV) trials using a new formulation of deltamethrin (DeltaGard®) demonstrated that it provided some control (average of 56% death in sentinel cages in a 91.4 m spray swath) after a single truck mounted aerial ULV application in residential areas.

  3. Laboratory strains of Aedes aegypti are competent to Brazilian Zika virus

    PubMed Central

    Ioshino, Rafaella Sayuri; de Araújo, Helena Rocha Corrêa; Kojin, Bianca Burini; Zanotto, Paolo Marinho de Andrade; Oliveira, Danielle Bruna Leal; Melo, Stella Rezende; Durigon, Edison Luiz

    2017-01-01

    The Zika virus outbreaks are unprecedented human threat in relation to congenital malformations and neurological/autoimmune complications. Since this virus has high potential to spread in regions presenting the vectors, improvement in mosquito control is a top priority. Thus, Aedes aegypti laboratory strains will be fundamental to support studies in different research fields implicated on Zika-mosquito interactions which are the basis for the development of innovative control methods. In this sense, our aim was to determine the main infection aspects of a Brazilian Zika strain in reference Aedes aegypti laboratory mosquitoes. We orally exposed Rockefeller, Higgs and Rexville mosquitoes to the Brazilian ZIKV (ZIKVBR) and qRT-PCR was applied to determine the infection, dissemination and detection rates of ZIKV in the collected saliva as well as viral levels in mosquito tissues. The three strains sustain the virus development but Higgs showed significantly lower viral loads in bodies at 14 days post-infection (dpi) and the lowest prevalences in bodies and heads. The Rockefeller strain was the most susceptible at 7 dpi but similar dissemination rates were observed at 14 dpi. Although variations exist, the ZIKVBR RNA shows detectable levels in saliva of the three strains at 14 dpi but is only detected in Rockefeller at 7 dpi. Moreover, saliva samples from the three strains were confirmed to be infectious when intrathoracically injected into mosquitoes. The ZIKVBR kinetics was monitored in Rockefeller mosquitoes and virus could be identified in the heads at 4 dpi but was more consistently detected late in infection. Our study presents the first evaluation on how Brazilian Zika virus behaves in reference Aedes aegypti strains and shed light on how the infection evolves over time. Vector competence and hallmarks of the ZIKVBR development were revealed in laboratory mosquitoes, providing additional information to accelerate studies focused on ZIKV-mosquito interactions

  4. Virulency of novel nanolarvicide from Trichoderma atroviride against Aedes aegypti (Linn.): a CLSM analysis.

    PubMed

    Singh, Gavendra; Prakash, Soam

    2015-08-01

    Aedes aegypti is the vector for transmitting dengue, chikungunya, and yellow fever. These diseases' transmission has increased predominantly in urban and semi-urban areas as a major public health concern. In present investigation, Trichoderma atroviride culture filtrates were used for the synthesis of silver nanoparticle. Moreover, T. atroviride is a free-living and rapidly growing fungi common in soil and root ecosystem. This fungi is an exceptionally good model for biocontrol and more significant as a bioagent. T. atroviride was grown in malt extract. T. atroviride culture filtrates were exposed to silver nitrates solution for 24 h at 25 °C for the synthesis of silver nanoparticles (AgNPs). These AgNPs were characterized to find their unique properties with UV-visible spectrophotometer and transmission electron microscope (TEM) analysis. The T. atroviride culture filtrates have formed hexagonal (diamond shape) AgNPs with the range of size of 14.01-21.02 nm. These AgNPs have shown significant efficacies against first, second, third, and fourth instar larvae of A. aegypti. The LC90 and LC99 values for the first instar were 1 and 3 ppm, second instar 2 and 3.18 ppm, third instar 3.12 and 4.12 ppm, and fourth instar 6.30 and 6.59 ppm, respectively, after an exposure of 7 h. The confocal laser scanning microscopy (CLSM) studies were verdict that these AgNPs embedded in the cuticle of larvae and cause instant lethality in 7 h. Present investigations have demonstrated that the AgNPs of T. atroviride culture filtrates synthesized can be used for larvae control of A. aegypti. T. atroviride is synthesized to silver nanoparticles to be a promising new candidate for application in mosquito control. We therefore suggested that the ability of T. atroviride culture filtrates in synthesis can also be explored for synthesizing silver nanoparticles for commercial exploitation.

  5. Efficacy of fungus mediated silver and gold nanoparticles against Aedes aegypti larvae.

    PubMed

    Soni, Namita; Prakash, Soam

    2012-01-01

    Chrysosporium tropicum is a pathogenic fungus. It is known to be an effective mosquito control agent. In the present study, we have synthesized the silver and gold nanoparticles using C. tropicum. These nanoparticles have been characterized through Microscan reader, X-ray diffractometer, transmission electron microscopy, and further confirmed by scanning electron microscopy. The characterization study confirmed the spherical shape and size (2-15 and 20-50 nm) of gold and silver nanoparticles. These silver and gold nanoparticles have been tested as a larvicide against the Aedes aegypti larvae. The larvicidal efficacy was noted when performed against all instars of A. aegypti at six different log concentrations, and significant results could be observed. The gold nanoparticles used as an efficacy enhancer have shown mortality at three times higher concentration than the silver nanoparticles. The larval mortality was observed after different time of exposures. The mortality values were obtained using the probit analysis. The larvae of A. aegypti were found to be highly susceptible for the silver nanoparticles. The second instar larvae have shown 100% mortality against the silver nanoparticles after 1 h, whereas the first, third, and fourth instars have shown efficacy (LC(50) = 3.47, 4, and 2; LC(90) = 12.30, 8.91, and 4; LC(99) = 13.18, 13.18, and 7.58, respectively) after 1 h. The results could suggest that the use of fungus C. tropicum, silver, and gold nanoparticles is a rapid, environmentally safer, and greener approach for mosquito control. This could lead us to a new possibility in vector control strategy.

  6. Comparison of BG-Sentinel® Trap and Oviposition Cups for Aedes aegypti and Aedes albopictus Surveillance in Jacksonville, Florida, USA.

    PubMed

    Wright, Jennifer A; Larson, Ryan T; Richardson, Alec G; Cote, Noel M; Stoops, Craig A; Clark, Marah; Obenauer, Peter J

    2015-03-01

    The BG-Sentinel® (BGS) trap and oviposition cups (OCs) have both proven effective in the surveillance of Aedes species. This study aimed to determine which of the 2 traps could best characterize the relative population sizes of Aedes albopictus and Aedes aegypti in an urban section of Jacksonville, FL. Until 1986, Ae. aegypti was considered the dominant container-breeding species in urban northeastern Florida. Since the introduction of Ae. albopictus, Ae. aegypti has become almost completely extirpated. In 2011, a resurgence of Ae. aegypti was detected in the urban areas of Jacksonville; thus this study initially set out to determine the extent of Ae. aegypti reintroduction to the area. We determined that the BGS captured a greater number of adult Ae. aegypti than Ae. albopictus, while OCs did not monitor significantly different numbers of either species, even in areas where the BGS traps suggested a predominance of one species over the other. Both traps were effective at detecting Aedes spp.; however, the BGS proved more diverse by detecting over 20 other species as well. Our results show that in order to accurately determine vectorborne disease threats and the impact of control operations on these 2 species, multiple trapping techniques should be utilized when studying Ae. aegypti and Ae. albopictus population dynamics.

  7. The impact of temperature on the bionomics of Aedes (Stegomyia) aegypti, with special reference to the cool geographic range margins.

    PubMed

    Eisen, Lars; Monaghan, Andrew J; Lozano-Fuentes, Saul; Steinhoff, Daniel F; Hayden, Mary H; Bieringer, Paul E

    2014-05-01

    The mosquito Aedes (Stegomyia) aegypti (L.), which occurs widely in the subtropics and tropics, is the primary urban vector of dengue and yellow fever viruses, and an important vector of chikungunya virus. There is substantial interest in how climate change may impact the bionomics and pathogen transmission potential of this mosquito. This Forum article focuses specifically on the effects of temperature on the bionomics of Ae. aegypti, with special emphasis on the cool geographic range margins where future rising temperatures could facilitate population growth. Key aims are to: 1) broadly define intra-annual (seasonal) patterns of occurrence and abundance of Ae. aegypti, and their relation to climate conditions; 2) synthesize the existing quantitative knowledge of how temperature impacts the bionomics of different life stages of Ae. aegypti; 3) better define the temperature ranges for which existing population dynamics models for Ae. aegypti are likely to produce robust predictions; 4) explore potential impacts of climate warming on human risk for exposure to Ae. aegypti at its cool range margins; and 5) identify knowledge or data gaps that hinder our ability to predict risk of human exposure to Ae. aegypti at the cool margins of its geographic range now and in the future. We first outline basic scenarios for intra-annual occurrence and abundance patterns for Ae. aegypti, and then show that these scenarios segregate with regard to climate conditions in selected cities where they occur. We then review how near-constant and intentionally fluctuating temperatures impact development times and survival of eggs and immatures. A subset of data, generated in controlled experimental studies, from the published literature is used to plot development rates and survival of eggs, larvae, and pupae in relation to water temperature. The general shape of the relationship between water temperature and development rate is similar for eggs, larvae, and pupae. Once the lower

  8. Gustatory Receptor Expression in the Labella and Tarsi of Aedes aegypti

    DTIC Science & Technology

    2013-01-01

    other animals. 2. Materials and methods 2.1. Animal rearing Ae. aegypti eggs (Orlando strain) were obtained from the Center for Medical and Veterinary ...target gene using KiCqStart SYBR Green qPCR ReadyMix iQ (Sigmae Aldrich, St. Louis, MO, USA) and an iCycler iQ Real-Time PCR Detection System (Bio-Rad...Hercules, California, USA). All Ct values (Table S2) were calculated by Bio-Rad iQ5 Optical System Software (Bio-Rad, Hercules, California, USA

  9. Metarhizium brunneum Blastospore Pathogenesis in Aedes aegypti Larvae: Attack on Several Fronts Accelerates Mortality

    PubMed Central

    Alkhaibari, Abeer M.; Carolino, Aline T.; Yavasoglu, Sare I.; Maffeis, Thierry; Mattoso, Thalles C.; Bull, James C.; Samuels, Richard I.; Butt, Tariq M.

    2016-01-01

    Aedes aegypti is the vector of a wide range of diseases (e.g. yellow fever, dengue, Chikungunya and Zika) which impact on over half the world’s population. Entomopathogenic fungi such as Metarhizium anisopliae and Beauveria bassiana have been found to be highly efficacious in killing mosquito larvae but only now are the underlying mechanisms for pathogenesis being elucidated. Recently it was shown that conidia of M. anisopliae caused stress induced mortality in Ae. aegypti larvae, a different mode of pathogenicity to that normally seen in terrestrial hosts. Blastospores constitute a different form of inoculum produced by this fungus when cultured in liquid media and although blastospores are generally considered to be more virulent than conidia no evidence has been presented to explain why. In our study, using a range of biochemical, molecular and microscopy methods, the infection process of Metarhizium brunneum (formerly M. anisopliae) ARSEF 4556 blastospores was investigated. It appears that the blastospores, unlike conidia, readily adhere to and penetrate mosquito larval cuticle. The blastospores are readily ingested by the larvae but unlike the conidia are able infect the insect through the gut and rapidly invade the haemocoel. The fact that pathogenicity related genes were upregulated in blastospores exposed to larvae prior to invasion, suggests the fungus was detecting host derived cues. Similarly, immune and defence genes were upregulated in the host prior to infection suggesting mosquitoes were also able to detect pathogen-derived cues. The hydrophilic blastospores produce copious mucilage, which probably facilitates adhesion to the host but do not appear to depend on production of Pr1, a cuticle degrading subtilisin protease, for penetration since protease inhibitors did not significantly alter blastospore virulence. The fact the blastospores have multiple routes of entry (cuticle and gut) may explain why this form of the inoculum killed Ae. aegypti

  10. Growth and development of Aedes aegypti larvae at limiting food concentrations.

    PubMed

    Levi, Tal; Ben-Dov, Eitan; Shahi, Preeti; Borovsky, Dov; Zaritsky, Arieh

    2014-05-01

    Mosquitoes have a complex life-cycle with dramatic changes in shape, function, and habitat. Aedes aegypti was studied by growing individual larvae at different concentrations of a defined rich food source. At higher food concentrations, rate of larval growth was faster, but the time required for 4th instar larvae to molt into the pupal stage was unexpectedly extended. These opposite tendencies resulted in constant times from hatching to pupation and up to adult eclosion at permissive food concentrations. The results demonstrate that nutritional conditions of 4th instar larvae impact initiation of the first metamorphic molt.

  11. Insecticide susceptibility of the dengue vector, Aedes aegypti (L.) in Metropolitan Bangkok.

    PubMed

    Komalamisra, Narumon; Srisawat, Raweewan; Phanbhuwong, Theerawit; Oatwaree, Sompis

    2011-07-01

    Mosquito larvae were collected from the houses of dengue infected patients in Bangkok, Thailand from 55 sites (36 out of the 50 districts of Metropolitan Bangkok). Aedes aegypti larvae were tested against temephos using WHO bioassay techniques. Adult mosquitoes were tested for susceptibility to permethrin, deltamethrin, cyfluthrin, malathion and DDT using WHO diagnostic doses. Most of the larvae tested were susceptible to temephos. Only few specimens were resistant to temephos. Most adult mosquitoes were highly susceptible to malathion. Deltamethrin resistance was seen in 6 districts of Bangkok. Variable levels of susceptibility were seen with cyfluthrin. Most of the specimens showed resistance to permethrin and all specimens were resistant to DDT.

  12. Ultra-low-volume ground aerosols of technical malathion for the control of Aedes aegypti L

    PubMed Central

    Pant, C. P.; Mount, G. A.; Jatanasen, Sujarti; Mathis, H. L.

    1971-01-01

    The efficacy of malathion aerosols applied from the ground was evaluated for the control of Ae. aegypti. Several techniques for applying the aerosols to an inhabited locality were investigated, and it was found that excellent control of adult mosquitos could be obtained with a dosage of 438 ml/ha. Two treatments carried out 3 days apart enabled the adult mosquito population to be reduced by 99%, and it took about 2 weeks to regain its pretreatment level. Schedules of treatment and strategies to be applied during an epidemic are discussed. PMID:5317014

  13. How Much Does Inbreeding Reduce Heterozygosity? Empirical Results from Aedes aegypti.

    PubMed

    Powell, Jeffrey R; Evans, Benjamin R

    2017-01-11

    Deriving strains of mosquitoes with reduced genetic variation is useful, if not necessary, for many genetic studies. Inbreeding is the standard way of achieving this. Full-sib inbreeding the mosquito Aedes aegypti for seven generations reduced heterozygosity to 72% of the initial heterozygosity in contrast to the expected 13%. This deviation from expectations is likely due to high frequencies of deleterious recessive alleles that, given the number of markers studied (27,674 single nucleotide polymorphisms [SNPs]), must be quite densely spread in the genome.

  14. The relative importance and distribution of Aedes polynesiensis and Ae. aegypti larval habitats in Samoa.

    PubMed

    Samarawickrema, W A; Sone, F; Kimura, E; Self, L S; Cummings, R F; Paulson, G S

    1993-01-01

    In preparation for a Filariasis Control programme in Samoa, during 1978 monthly larval surveys of the vector mosquito Aedes polynesiensis were carried out in four study villages in the main island of Upolu. A more extensive survey of larval habitat distribution was then made in twenty-two villages of Upolu and eighteen of Savai'i island, to determine the importance of habitat types according to their abundance, volume of water and whether their productivity was permanent or seasonal. Ae.aegypti larval densities and habitat distribution were also monitored and the occurrence of predatory Toxorhynchites amboinensis larvae in northern Upolu was recorded from forty-one collections. Aedes Breteau and container indices fluctuated with the pattern of rainfall in two coastal villages and an inland bush village, but not in a coconut plantation community. The five main Aedes larval habitat types encountered were: 200 litre water-storage drums, discarded tins and bottles, coconut shells, automobile tyres and treeholes. Aedes immatures occurred perennially in drums and tree holes, but breeding discontinued in tins, bottles and coconut shells during the driest month of July. For Ae. polynesiensis in Upolu the Breteau and container indices of 104.5 +/- SD 80.9 and 35.3 +/- 12.4 respectively were significantly higher than those in Savai'i: 33.1 +/- 25.0 and 24.3 +/- 20.0 respectively. Likewise for Ae.aegypti the Breteau and container indices of 50.8 +/- 32.5 and 23.9 +/- 15.6, respectively, were also significantly higher than those in Savai'i: 12.7 +/- 17.1 and 9.4 +/- 13.2 respectively. Habitat types greater or lesser importance were determined by plotting the percentage of each type of cotnainer utilized for Aedes breeding against the percentage of ech type amongst all larva-positive containers. Ae.polynesiensis preferred tree-holes but not water-storage drums. Ae.aegypti preferred drums and tyres; mixed populations of larvae of both species were commonest in these two types of

  15. Egg and fourth instar larvae gut of Aedes aegypti as a source of stem cells.

    PubMed

    Mario, Lara C; Borghesi, Jéssica; Crivellari-Damasceno, Wilson T; Favaron, Phelipe O; Carreira, Ana Claudia O; Will, Sonia E A L; Maria, Durvanei A; Miglino, Maria A

    2016-10-01

    According to the World Health Organization, 2015 registered more than 1.206.172 cases of Dengue in the Americas. Recently, the Aedes aegypti has been not only related to Dengue, but also with cases of Zika virus and Chikungunya. Due to its epidemiological importance, this study characterized the morphology of the embryonated eggs of A. aegypti and provided a protocol to culture stem cells from eggs and digestive tract of fourth instar larvae in order to examine cell biology and expression of markers in these vectors. Cells were isolated and cultured in DMEM-High at 28°C, and their morphology, cell cycle and immunophenotyping were examined. Morphologically, embryos were at the end of the embryonic period and showed: head, thorax, and abdomen with eight abdominal segments. The embryonic tissues expressed markers related to cell proliferation (PCNA), pluripotency (Sox2 and OCT3/4), neural cells (Nestin), mesenchymal cells (Vimentin and Stro-1), and endosomal cells (GM130 and RAB5). In culture, cells from both tissues (eggs and larvae gut) were composed by a heterogeneous population. The cells had a globoid shape and small size. Cell cycle analysis on passage 1 (P1) showed 27.5%±2.0% of cell debris, 68% of cells on G0-G1 phase, 30.2% on S phase, 1.9%±0.5% on G2-M phase. In addition, cells on passage 2 showed: 10% of cell debris, 92.4% of cells on G0-G1 phase, 6.8% on S phase, 0.6% on G2-M phase. Embryonated eggs expressed markers involved with pluripotency (Sox2 and Oct 3/4), mesenchymal cells (vimentin and Stro-1), neural cells (Nestin), and cellular death by apoptosis (Caspase 3). Specific endosomal markers for insect cells (GM130 and RAB5) were also highly expressed. In cell culture of A. aegypti larvae gut the same labeling pattern was observed, with a small decrease in the expression of mesenchymal (vimentin and Stro-1) and neural (Nestin) markers. In summary, we were able to establish a protocol to culture embryonated eggs and larvae gut of A. aegypti

  16. [Toxicity of isolates of Bacillus thuringiensis from Wroclaw against larvae of Aedes aegypti].

    PubMed

    Lonc, E; Kucińska, J; Rydzanicz, K

    2001-01-01

    Seven field isolates of Bacillus thuringiensis from the Lower Silesia, region of Poland, the Osola plain and phylloplane niches and soil samples from the Karkonosze National Park were tested in vitro for insecticidal activity against mosquito larvae Aedes aegypti. Both the spore/crystal mixture and pured crystals from B. thuringienis strains KpC1, KpF3 and OpQ3 (belonging to the first physiological group including the subspecies japonensis, yoso, jinghongiensis ) proved to be the most active against insects (61-65% of corrected mortality). The lowest toxicity (7-28% mortality) was caused by B. thuringiensis wratislaviensis strains (PO12 and 13).

  17. Promising Aedes aegypti Repellent Chemotypes Identified through Integrated QSAR, Virtual Screening, Synthesis, and Bioassay

    PubMed Central

    Oliferenko, Polina V.; Oliferenko, Alexander A.; Poda, Gennadiy I.; Osolodkin, Dmitry I.; Pillai, Girinath G.; Bernier, Ulrich R.; Tsikolia, Maia; Agramonte, Natasha M.; Clark, Gary G.; Linthicum, Kenneth J.; Katritzky, Alan R.

    2013-01-01

    Molecular field topology analysis, scaffold hopping, and molecular docking were used as complementary computational tools for the design of repellents for Aedes aegypti, the insect vector for yellow fever, chikungunya, and dengue fever. A large number of analogues were evaluated by virtual screening with Glide molecular docking software. This produced several dozen hits that were either synthesized or procured from commercial sources. Analysis of these compounds by a repellent bioassay resulted in a few highly active chemicals (in terms of minimum effective dosage) as viable candidates for further hit-to-lead and lead optimization effort. PMID:24039693

  18. Oral receptivity of Aedes aegypti from Cape Verde for yellow fever, dengue, and chikungunya viruses.

    PubMed

    Vazeille, Marie; Yébakima, André; Lourenço-de-Oliveira, Ricardo; Andriamahefazafy, Barrysson; Correira, Artur; Rodrigues, Julio Monteiro; Veiga, Antonio; Moreira, Antonio; Leparc-Goffart, Isabelle; Grandadam, Marc; Failloux, Anna-Bella

    2013-01-01

    At the end of 2009, 21,313 cases of dengue-3 virus (DENV-3) were reported in the islands of Cape Verde, an archipelago located in the Atlantic Ocean 570 km from the coast of western Africa. It was the first dengue outbreak ever reported in Cape Verde. Mosquitoes collected in July 2010 in the city of Praia, on the island of Santiago, were identified morphologically as Aedes aegypti formosus. Using experimental oral infections, we found that this vector showed a moderate ability to transmit the epidemic dengue-3 virus, but was highly susceptible to chikungunya and yellow fever viruses.

  19. Seasonal Differences in Density But Similar Competitive Impact of Aedes albopictus (Skuse) on Aedes aegypti (L.) in Rio de Janeiro, Brazil.

    PubMed

    Camara, Daniel Cardoso Portela; Codeço, Claudia Torres; Juliano, Steven A; Lounibos, L Philip; Riback, Thais Irene Souza; Pereira, Glaucio Rocha; Honorio, Nildimar Alves

    2016-01-01

    Previous studies have shown that the negative effects of density of Ae. albopictus on Ae. aegypti exceed those of Ae. aegypti on Ae. albopictus for population growth, adult size, survivorship, and developmental rate. This competitive superiority has been invoked to explain the displacement of Ae. aegypti by Ae. albopictus in the southeastern USA. In Brazil, these species coexist in many vegetated suburban and rural areas. We investigated a related, but less-well-studied question: do effects of Ae. albopictus on Ae. aegypti larval development and survival occur under field conditions at realistic densities across multiple seasons in Brazil? We conducted additive competition experiments in a vegetated area of Rio de Janeiro where these species coexist. We tested the hypothesis that Ae. aegypti (the focal species, at a fixed density) suffers negative effects on development and survivorship across a gradient of increasing densities of Ae. albopictus (the associate species) in three seasons. The results showed statistically significant effects of both season and larval density on Ae. aegypti survivorship, and significant effects of season on development rate, with no significant season-density interactions. Densities of Aedes larvae in these habitats differed among seasons by a factor of up to 7x. Overall, Spring was the most favorable season for Ae. aegypti survivorship and development. Results showed that under natural conditions the negative competitive effects of Ae. albopictus on Ae. aegypti were expressed primarily as lower survivorship. Coexistence between Ae. aegypti and Ae. albopictus in vegetated areas is likely affected by seasonal environmental differences, such as detrital resource levels or egg desiccation, which can influence competition between these species. Interactions between these Aedes are important in Brazil, where both species are well established and widely distributed and vector dengue, Zika and chikungunya viruses.

  20. Seasonal Differences in Density But Similar Competitive Impact of Aedes albopictus (Skuse) on Aedes aegypti (L.) in Rio de Janeiro, Brazil

    PubMed Central

    Camara, Daniel Cardoso Portela; Codeço, Claudia Torres; Juliano, Steven A.; Lounibos, L. Philip; Riback, Thais Irene Souza; Pereira, Glaucio Rocha; Honorio, Nildimar Alves

    2016-01-01

    Previous studies have shown that the negative effects of density of Ae. albopictus on Ae. aegypti exceed those of Ae. aegypti on Ae. albopictus for population growth, adult size, survivorship, and developmental rate. This competitive superiority has been invoked to explain the displacement of Ae. aegypti by Ae. albopictus in the southeastern USA. In Brazil, these species coexist in many vegetated suburban and rural areas. We investigated a related, but less-well-studied question: do effects of Ae. albopictus on Ae. aegypti larval development and survival occur under field conditions at realistic densities across multiple seasons in Brazil? We conducted additive competition experiments in a vegetated area of Rio de Janeiro where these species coexist. We tested the hypothesis that Ae. aegypti (the focal species, at a fixed density) suffers negative effects on development and survivorship across a gradient of increasing densities of Ae. albopictus (the associate species) in three seasons. The results showed statistically significant effects of both season and larval density on Ae. aegypti survivorship, and significant effects of season on development rate, with no significant season-density interactions. Densities of Aedes larvae in these habitats differed among seasons by a factor of up to 7x. Overall, Spring was the most favorable season for Ae. aegypti survivorship and development. Results showed that under natural conditions the negative competitive effects of Ae. albopictus on Ae. aegypti were expressed primarily as lower survivorship. Coexistence between Ae. aegypti and Ae. albopictus in vegetated areas is likely affected by seasonal environmental differences, such as detrital resource levels or egg desiccation, which can influence competition between these species. Interactions between these Aedes are important in Brazil, where both species are well established and widely distributed and vector dengue, Zika and chikungunya viruses. PMID:27322537

  1. Bicluster pattern of codon context usages between flavivirus and vector mosquito Aedes aegypti: relevance to infection and transcriptional response of mosquito genes.

    PubMed

    Behura, Susanta K; Severson, David W

    2014-10-01

    The mosquito Aedes aegypti is the primary vector of dengue virus (DENV) infection in most of the subtropical and tropical countries. Besides DENV, yellow fever virus (YFV) is also transmitted by A. aegypti. Susceptibility of A. aegypti to West Nile virus (WNV) has also been confirmed. Although studies have indicated correlation of codon bias between flaviviridae and their animal/insect hosts, it is not clear if codon sequences have any relation to susceptibility of A. aegypti to DENV, YFV and WNV. In the current study, usages of codon context sequences (codon pairs for neighboring amino acids) of the vector (A. aegypti) genome as well as the flaviviral genomes are investigated. We used bioinformatics methods to quantify codon context bias in a genome-wide manner of A. aegypti as well as DENV, WNV and YFV sequences. Mutual information statistics was applied to perform bicluster analysis of codon context bias between vector and flaviviral sequences. Functional relevance of the bicluster pattern was inferred from published microarray data. Our study shows that codon context bias of DENV, WNV and YFV sequences varies in a bicluster manner with that of specific sets of genes of A. aegypti. Many of these mosquito genes are known to be differentially expressed in response to flaviviral infection suggesting that codon context sequences of A. aegypti and the flaviviruses may play a role in the susceptible interaction between flaviviruses and this mosquito. The bias in usages of codon context sequences likely has a functional association with susceptibility of A. aegypti to flaviviral infection. The results from this study will allow us to conduct hypothesis-driven tests to examine the role of codon context bias in evolution of vector-virus interactions at the molecular level.

  2. Preliminary data on the performance of Aedes aegypti and Aedes albopictus immatures developing in water-filled tires in Rio de Janeiro.

    PubMed

    Honório, Nildimar Alves; Cabello, Pedro H; Codeço, Cláudia T; Lourenço-de-Oliveira, Ricardo

    2006-03-01

    A monthly survey of Aedes aegypti and Aedes albopictus immatures in discarded tires at a site in metropolitan Rio de Janeiro showed that Ae. albopictus was much more abundant in the rainy season, but Ae. aegypti abundance showed a less clear seasonal pattern. Pupal masses for Ae. albopictus showed a seasonal trend. In contrast, Ae. aegypti pupae did not show any clear trend in weight. Large Ae. albopictus pupae were found in the warmer months, when water volume was higher, pH lower and larval abundance lower. Further studies should be carried out to assess how seasonal variations in body size may impact vector competence of these species in Brazil.

  3. Nam Con Son Basin

    SciTech Connect

    Tin, N.T.; Ty, N.D.; Hung, L.T.

    1994-07-01

    The Nam Con Son basin is the largest oil and gas bearing basin in Vietnam, and has a number of producing fields. The history of studies in the basin can be divided into four periods: Pre-1975, 1976-1980, 1981-1989, and 1990-present. A number of oil companies have carried out geological and geophysical studies and conducted drilling activities in the basin. These include ONGC, Enterprise Oil, BP, Shell, Petro-Canada, IPL, Lasmo, etc. Pre-Tertiary formations comprise quartz diorites, granodiorites, and metamorphic rocks of Mesozoic age. Cenozoic rocks include those of the Cau Formation (Oligocene and older), Dua Formation (lower Miocene), Thong-Mang Cau Formation (middle Miocene), Nam Con Son Formation (upper Miocene) and Bien Dong Formation (Pliocene-Quaternary). The basement is composed of pre-Cenozoic formations. Three fault systems are evident in the basin: north-south fault system, northeast-southwest fault system, and east-west fault system. Four tectonic zones can also be distinguished: western differentiated zone, northern differentiated zone, Dua-Natuna high zone, and eastern trough zone.

  4. A leucokinin mimic elicits aversive behavior in mosquito Aedes aegypti (L.) and inhibits the sugar taste neuron

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insect kinins (leucokinins) are multifunctional peptides acting as neurohormones and neurotransmitters. In females of the mosquito vector Aedes aegypti (L.), aedeskinins are known to stimulate fluid secretion from the renal organs (Malpighian tubules) and hindgut contractions by activating a G prot...

  5. Improving the effectiveness of three essential oils against Aedes aegypti (Linn.) and Anopheles dirus (Peyton and Harrison).

    PubMed

    Auysawasdi, Nutthanun; Chuntranuluck, Sawitri; Phasomkusolsil, Siriporn; Keeratinijakal, Vichien

    2016-01-01

    Repellency of essential oil extracted from Curcuma longa, Eucalyptus globulus, and Citrus aurantium at various concentrations (5, 10, 15, 20, and 25 %) with and without 5 % vanillin was evaluated against female mosquitoes: Aedes aegypti and Anopheles dirus. The comparisons were made with a commercial chemical repellent (N,N-diethyl-3-methylbenzamide (DEET) 25 % w/w; KOR YOR 15) by arm in cage method. It was found that the essential oils with 5 % vanillin gave the longest lasting period against two mosquitoes as follows: Curcuma longa gave 150 min for Ae. aegypti, 480 min for An. dirus; Eucalyptus globulus gave 144 min for Ae. aegypti, 390 min for An. dirus; and Citrus aurantium gave 120 min for Ae. aegypti, 360 min for An. dirus. The 25 % Curcuma longa essential oil exhibited the best efficiency as equal as a commercial repellent (480 min against An. dirus). Vanillin can extend the period of time in protection against the two mosquitoes. This study indicates the potential uses of the essential oils (Curcuma longa, Eucalyptus globulus, and Citrus aurantium) with vanillin as natural mosquito repellents.

  6. [Aedes (Stegomyia) aegypti (Linnaeus, 1762) breeding sites in native bromeliads in Vitória City, ES].

    PubMed

    Varejão, José Benedito Malta; Santos, Claudiney Biral dos; Rezende, Helder Ricas; Bevilacqua, Luiz Carlos; Falqueto, Aloísio

    2005-01-01

    Some insects that are vectors of human diseases have accompanied man in his migrations throughout the world and breed exclusively in the proximity of human dwellings. The mosquito Aedes aegypti has been responsible for epidemics of dengue in Brazil and its presence also constitutes a serious risk for future outbreaks of urban yellow fever. The failure of campaigns to eradicate this species justifies the search for alternative breeding sites, which may be beyond the reach of present control measures. In this study the occurrence of Aedes aegypti breeding sites in native bromeliads on rocky slopes was investigated in five areas of Vitória, capital of the Brazilian State of Espírito Santo, ES. Water contained in the bromeliads was collected with the aid of a suction apparatus to search for culicid larvae. The degree of infestation of buildings in adjacent urban areas was evaluated simultaneously. Culicid larvae were found in bromeliads in four of the five areas investigated, Aedes aegypti being present in two areas. The presence of breeding sites in bromeliads was not related to indices of infestation of buildings in adjacent areas. Further studies are necessary to define whether breeding sites in bromeliads constitute primary foci of Aedes aegypti, or are a consequence of high infestation levels in urban areas.

  7. Replicate surveys of larval habitats of Aedes aegypti in relation to dengue haemorrhagic fever in Bangkok, Thailand*

    PubMed Central

    Tonn, R. J.; Sheppard, P. M.; MacDonald, W. W.; Bang, Y. H.

    1969-01-01

    Dengue haemorrhagic fever in Bangkok and Thonburi occurs principally during the wet season. The mosquito vector is Aedes aegypti. A study was made of the larval habitats of A. aegypti in 14 localities, at three different times of the year, to determine whether there were fluctuations in the A. aegypti population, as measured by the number of occupied habitats, which could be correlated with the incidence of the infection. The habitats were classified into 6 categories and a single larva was collected for identification from each one that was occupied. The number and percentage of occupied habitats of each category per 100 houses were analysed to determine whether there were differences between localities and between times of the year. Almost all the comparisons between localities were highly significant. There was evidence of slight changes in the number of occupied habitats from time to time, the chief increase being between the cool and the warm seasons and the chief decrease from the wet to the cool season, but it seems unlikely that outbreaks of dengue haemorrhagic fever can be explained by increases in A. aegypti densities during the wet season. PMID:5307596

  8. Selection of insensitive acetylcholinesterase as a resistance mechanism in Aedes aegypti (Diptera: Culicidae) from Santiago de Cuba.

    PubMed

    Bisset, Juan; Rodríguez, María M; Fernández, Ditter

    2006-11-01

    A sample of Aedes aegypti (L.) (Diptera: Culicidae) from Santiago de Cuba, Cuba, with a high level of propoxur resistance compared with the reference susceptible Rockefeller strain (12.60 x at the 50% lethal concentration [LC50] and 18.08 at the 90% lethal concentration [LC90]), with a 4.3% frequency of insensitive acetylcholinesterase (AChE) frequency, was subjected to propoxur selection for 13 successive generations to increase the frequency of this resistance mechanism in Ae. aegypti. High resistance to propoxur was developed during this selection (41.73-fold), and the frequency of insensitive AChE mechanism was increased 13.25-fold. Other mechanisms (overproduced esterases, glutathione transferases, or monooxygenases) were not detected in the propoxur-selected strain. The selection of an insensitive AChE resistance mechanism in Ae. aegypti has important implications and will be a valuable resource for genetic studies and molecular characterization of the ace gene mutation(s) associated with insecticide resistance in Ae. aegypti.

  9. Vacant lots: productive sites for Aedes (Stegomyia) aegypti (Diptera: Culicidae) in Mérida City, México.

    PubMed

    Baak-Baak, Carlos M; Arana-Guardia, Roger; Cigarroa-Toledo, Nohemi; Loroño-Pino, Maria Alba; Reyes-Solis, Guadalupe; Machain-Williams, Carlos; Beaty, Barry J; Eisen, Lars; García-Rejón, Julián E

    2014-03-01

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

  10. Sterility introduced by release of genetically altered males to a domestic population of Aedes aegypti at the Kenya coast.

    PubMed

    McDonald, P T; Hausermann, W; Lorimer, N

    1977-05-01

    The release of males heterozygous for one or two sex-linked translocations was effective in introducing a high level of sterility into a domestic population of Aedes aegypti at a Rabai village. The effect of the releases continued for several weeks after the release period.

  11. Papyracillic acid and its derivatives as biting deterrents against Aedes aegypti(Diptera: Culicidae): structure–activity relationships

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aedes aegypti L. is the major vector of the arboviruses responsible for dengue fever, one of the most devastating human diseases. Papyracillic acid, the main phytotoxin produced by Ascochyta agropyrina var. nana, was evaluated in a preliminary screening together with other fungal phytotoxins, cyclo...

  12. Laboratory evaluation of the response of Aedes aegypti and Aedes albopictus uninfected and infected with dengue virus to deet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Laboratory studies were conducted to compare the response of Aedes aegypti (L.) and Aedes albopictus (Skuse) adults, uninfected and infected with four serotypes of dengue virus, to a repellent containing 5% deet. The results showed that mosquitoes infected with the four serotypes of dengue respond i...

  13. Behavioral responses of two dengue virus vectors, Aedes aegypti and Aedes albopictus (Diptera: Culicidae), to DUET TM and its components

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ultralow volume (ULV) droplets of DUET TM, prallethrin and sumithrin at a sublethal dose were applied to unfed (non bloodfed) and bloodfed female Aedes aegypti Linn. and Aedes albopictus (Skuse) in a wind tunnel. Control spray droplets only contained inactive ingredients. Individual mosquitoes wer...

  14. Complete Genome Sequence of Chikungunya Virus Isolated from an Aedes aegypti Mosquito during an Outbreak in Yemen, 2011.

    PubMed

    Fahmy, Nermeen T; Klena, John D; Mohamed, Amr S; Zayed, Alia; Villinski, Jeffrey T

    2015-07-16

    Chikungunya virus is recognized as a serious public health problem. The complete genome was sequenced for a chikungunya virus isolated from the mosquito Aedes aegypti during a 2011 outbreak in Al Hodayda, Yemen, which resulted in significant human fatalities. Phylogenetic analysis demonstrated that this Yemeni isolate is most closely related to Indian Ocean strains of the east/central/south African genotype.

  15. Truck-mounted area-wide application of pyriproxyfen targeting Aedes aegypti and Aedes albopictus in northeast Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to determine the efficacy of truck-mounted ULV applications of pyriproxyfen against Aedes aegypti larvae in artificial water containers and wild adult Ae. albopictus populations in an urban setting. The study was conducted over a 3 ½ month period (Jun – Oct 2012), during wh...

  16. Worldwide patterns of genetic differentiation imply multiple ‘domestications’ of Aedes aegypti, a major vector of human diseases

    PubMed Central

    Brown, Julia E.; McBride, Carolyn S.; Johnson, Petrina; Ritchie, Scott; Paupy, Christophe; Bossin, Hervé; Lutomiah, Joel; Fernandez-Salas, Ildefonso; Ponlawat, Alongkot; Cornel, Anthony J.; Black, William C.; Gorrochotegui-Escalante, Norma; Urdaneta-Marquez, Ludmel; Sylla, Massamba; Slotman, Michel; Murray, Kristy O.; Walker, Christopher; Powell, Jeffrey R.

    2011-01-01

    Understanding the processes by which species colonize and adapt to human habitats is particularly important in the case of disease-vectoring arthropods. The mosquito species Aedes aegypti, a major vector of dengue and yellow fever viruses, probably originated as a wild, zoophilic species in sub-Saharan Africa, where some populations still breed in tree holes in forested habitats. Many populations of the species, however, have evolved to thrive in human habitats and to bite humans. This includes some populations within Africa as well as almost all those outside Africa. It is not clear whether all domestic populations are genetically related and represent a single ‘domestication’ event, or whether association with human habitats has developed multiple times independently within the species. To test the hypotheses above, we screened 24 worldwide population samples of Ae. aegypti at 12 polymorphic microsatellite loci. We identified two distinct genetic clusters: one included all domestic populations outside of Africa and the other included both domestic and forest populations within Africa. This suggests that human association in Africa occurred independently from that in domestic populations across the rest of the world. Additionally, measures of genetic diversity support Ae. aegypti in Africa as the ancestral form of the species. Individuals from domestic populations outside Africa can reliably be assigned back to their population of origin, which will help determine the origins of new introductions of Ae. aegypti. PMID:21227970

  17. Optomotor Reactions Reveal Polarization Sensitvity in the Zika Virus Transmitting Yellow Fever Mosquito Aedes (Stegomyia) aegypti (Diptera; Nematocera).

    PubMed

    Bernáth, Balazs; Meyer-Rochow, Victor Benno

    2016-12-01

    In polarization-sensitive insect species an orthogonal arrangement of photoreceptive microvilli is a characteristic feature. However, mosquito eyes had not revealed this feature, and polarization sensitivity (PS) was considered to be non-existent in them. Recently, however, gravid Aedes (Stegomyia) aegypti females were found to possess PS, sequels of which could be demonstrated only in the absence of chemicals emitted by conspecifics. Therefore, PS in Ae. aegypti, unlike that of other aquatic insects, apparently does not play a dominant role in locating water bodies, and is difficult to demonstrate in situations free of chemical cues. Here, we present behavioral evidence with Ae. aegypti females, exposed to large-field optomotor stimuli based solely on polarization contrast. Under conditions with stripes of alternating orthogonal directions of polarization, clear optomotor responses were elicited, no different from those in response to a rotating drum with vertical black and white stripes. Thus, Ae. aegypti is indeed polarization-sensitive; it reacts to vertically-striped contrast patterns with low spatial frequency on the basis of both intensity and polarization differences between the stripes.

  18. Comparative role of Aedes albopictus and Aedes aegypti in the emergence of Dengue and Chikungunya in central Africa.

    PubMed

    Paupy, Christophe; Ollomo, Benjamin; Kamgang, Basile; Moutailler, Sara; Rousset, Dominique; Demanou, Maurice; Hervé, Jean-Pierre; Leroy, Eric; Simard, Frédéric

    2010-04-01

    Since its discovery in Nigeria in 1991, Aedes albopictus has invaded much of Central Africa, a region where Ae. aegypti also occurs. To assess the relationship between the invasion by Ae. albopictus and the recent emergence of dengue virus (DENV) and chikungunya virus (CHIKV), we undertook vector competence experiments on populations collected from Cameroon and conducted field investigations during concurrent epidemics of DENV and CHIKV in Gabon. Overall, infection and dissemination rates were not significantly different between Ae. albopictus and Ae. aegypti when exposed to titers of 10(8.1) mosquito infectious dose 50/mL and 10(7.5) plaque forming units/mL of DENV type 2 and CHIKV, respectively. Field investigations showed that Ae. albopictus readily bit man, was abundant, and outnumbered Ae. aegypti to a large extent in Gabon, particularly in suburban environments. Nevertheless, Ae. aegypti was predominant in the more urbanized central parts of Libreville. In this city, CHIKV and DENV were detected only in Ae. albopictus. These data strongly suggest that Ae. albopictus acted as the major vector of both viruses in Libreville in 2007, impacting on the epidemiology of DENV and CHIKV in this area.

  19. Rapid and non-destructive detection and identification two strains of Wolbachia in Aedes aegypti by near-infrared spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated the potential of using near-infrared spectroscopy (NIRS) to detect the presence of Wolbachia pipientis (wMel) in male and female laboratory-reared Aedes aegypti mosquitoes. The release of Wolbachia transinfected mosquitoes is likely to form a key component of disease control strategi...

  20. Chemical Composition and Larvicidal Activity of Essential Oils Extracted from Brazilian Legal Amazon Plants against Aedes aegypti L. (Diptera: Culicidae)

    PubMed Central

    Dias, Clarice Noleto; Alves, Luciana Patrícia Lima; Rodrigues, Klinger Antonio da Franca; Brito, Maria Cristiane Aranha; Rosa, Carliane dos Santos; do Amaral, Flavia Maria Mendonça; Monteiro, Odair dos Santos; Andrade, Eloisa Helena de Aguiar; Maia, José Guilherme Soares; Moraes, Denise Fernandes Coutinho

    2015-01-01

    The mosquito Aedes aegypti L. (Diptera: Culicidae) is the major vector of dengue and chikungunya fever. The lack of effective therapies and vaccines for these diseases highlights the need for alternative strategies to control the spread of virus. Therefore, this study investigated the larvicidal potential of essential oils from common plant species obtained from the Chapada das Mesas National Park, Brazil, against third instar A. aegypti larvae. The chemical composition of these oils was determined by gas chromatography coupled to mass spectrometry. The essential oils of Eugenia piauhiensis Vellaff., Myrcia erythroxylon O. Berg, Psidium myrsinites DC., and Siparuna camporum (Tul.) A. DC. were observed to be mainly composed of sesquiterpene hydrocarbons. The essential oil of Lippia gracilis Schauer was composed of oxygenated monoterpenes. Four of the five tested oils were effective against the A. aegypti larvae, with the lethal concentration (LC50) ranging from 230 to 292 mg/L after 24 h of exposure. Overall, this work demonstrated the possibility of developing larvicidal products against A. aegypti by using essential oils from the flora of the Brazilian Legal Amazon. This in turn demonstrates the potential of using natural resources for the control of disease vectors. PMID:25949264

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

    PubMed Central

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

    2014-01-01

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

  2. Odonate Nymphs: Generalist Predators and Their Potential in the Management of Dengue Mosquito, Aedes aegypti (Diptera: Culicidae)

    PubMed Central

    Akram, Waseem; Ali-Khan, Hafiz Azhar

    2016-01-01

    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. PMID:27308283

  3. The effects of plant essential oils on escape response and mortality rate of Aedes aegypti and Anopheles minimus.

    PubMed

    Sathantriphop, Sunaiyana; Achee, Nicole L; Sanguanpong, Unchalee; Chareonviriyaphap, Theeraphap

    2015-12-01

    The High Throughput Screening System (HITSS) has been applied in insecticide behavioral response studies with various mosquito species. In general, chemical or natural compounds can produce a range of insect responses: contact irritancy, spatial repellency, knock-down, and toxicity. This study characterized these actions in essential oils derived from citronella, hairy basil, catnip, and vetiver in comparison to DEET and picaridin against Aedes aegypti and Anopheles minimus mosquito populations. Results indicated the two mosquito species exhibited significantly different (P<0.05) contact irritant escape responses between treatment and control for all tested compound concentrations, except with the minimum dose of picaridin (P>0.05) against Ae. aegypti. Spatial repellency responses were elicited in both mosquito species when exposed to all compounds, but the strength of the repellent response was dependent on compound and concentration. Data show that higher test concentrations had greatest toxic effects on both mosquito populations, but vetiver had no toxic effect on Ae. aegypti and picaridin did not elicit toxicity in either Ae. aegypti or An. minimus at any test concentration. Ultimately, this study demonstrates the ability of the HITSS assay to guide selection of effective plant essential oils for repelling, irritating, and killing mosquitoes.

  4. Swarming mechanisms in the yellow fever mosquito: aggregation pheromones are involved in the mating behavior of Aedes aegypti.

    PubMed

    Fawaz, Emadeldin Y; Allan, Sandra A; Bernier, Ulrich R; Obenauer, Peter J; Diclaro, Joseph W

    2014-12-01

    Mosquitoes of various species mate in swarms comprised of tens of thousands of flying males. In this study, we examined Aedes aegypti swarming behavior and identified associated chemical cues. Novel evidence is provided that Ae. aegypti females aggregate by means of olfactory cues, such as aggregation pheromones. Isolation of Ae. aegypti aggregation pheromones was achieved by aeration of confined mosquitoes and collection of associated volatiles by glass filters. The collected volatiles were identified through gas chromatography mass spectrometry (GCMS). Three aggregation pheromones were collected and identified as 2,6,6-trimethylcyclohex-2-ene-1,4-dione (ketoisophorone) (CAS# 1125-21-9, t(R) = 18.75), 2,2,6-trimethylcyclohexane-1,4-dione (the saturated analog of ketoisophorone) (CAS# 20547-99-3, t(R) = 20.05), and 1-(4-ethylphenyl) ethanone (CAS# 937-30-4, t(R) = 24.22). Our biological studies revealed that the identified compounds stimulated mosquito behavior under laboratory conditions. The mechanism of mosquito swarm formation is discussed in light of our behavioral study findings. A preliminary field trial demonstrated the potential application of the isolated aggregation pheromones in controlling Ae. aegypti.

  5. The effect of photoperiod on life history and blood-feeding activity in Aedes albopictus and Aedes aegypti (Diptera: Culicidae).

    PubMed

    Costanzo, K S; Schelble, S; Jerz, K; Keenan, M

    2015-06-01

    Several studies have examined how climatic variables such as temperature and precipitation may affect life history traits in mosquitoes that are important to disease transmission. Despite its importance as a seasonal cue in nature, studies investigating the influence of photoperiod on such traits are relatively few. This study aims to investigate how photoperiod alters life history traits, survival, and blood-feeding activity in Aedes albopictus (Skuse) and Aedes aegypti (Linnaeus). We performed three experiments that tested the effects of day length on female survival, development time, adult size, fecundity, adult life span, and propensity to blood feed in Ae. albopictus and Ae. aegypti. Each experiment had three photoperiod treatments: 1) short-day (10L:14D), 2) control (12L:12D), and 3) long-day (14L:10D). Aedes albopictus adult females were consistently larger in size when reared in short-day conditions. Aedes aegypti adult females from short-day treatments lived longer and were more likely to take a blood meal compared to other treatments. We discuss how species-specific responses may reflect alternative strategies evolved to increase survival during unfavorable conditions. We review the potential impacts of these responses on seasonal transmission patterns, such as potentially increasing vectorial capacity of Ae. aegypti during periods of shorter day lengths.

  6. Sialic acid expression in the mosquito Aedes aegypti and its possible role in dengue virus-vector interactions.

    PubMed

    Cime-Castillo, Jorge; Delannoy, Philippe; Mendoza-Hernández, Guillermo; Monroy-Martínez, Verónica; Harduin-Lepers, Anne; Lanz-Mendoza, Humberto; Hernández-Hernández, Fidel de la Cruz; Zenteno, Edgar; Cabello-Gutiérrez, Carlos; Ruiz-Ordaz, Blanca H

    2015-01-01

    Dengue fever (DF) is the most prevalent arthropod-borne viral disease which affects humans. DF is caused by the four dengue virus (DENV) serotypes, which are transmitted to the host by the mosquito Aedes aegypti that has key roles in DENV infection, replication, and viral transmission (vector competence). Mosquito saliva also plays an important role during DENV transmission. In this study, we detected the presence of sialic acid (Sia) in Aedes aegypti tissues, which may have an important role during DENV-vector competence. We also identified genome sequences encoding enzymes involved in Sia pathways. The cDNA for Aedes aegypti CMP-Sia synthase (CSAS) was amplified, cloned, and functionally evaluated via the complementation of LEC29.Lec32 CSAS-deficient CHO cells. AedesCSAS-transfected LEC29.Lec32 cells were able to express Sia moieties on the cell surface. Sequences related to α-2,6-sialyltransferase were detected in the Aedes aegypti genome. Likewise, we identified Sia-α-2,6-DENV interactions in different mosquito tissues. In addition, we evaluated the possible role of sialylated molecules in a salivary gland extract during DENV internalization in mammalian cells. The knowledge of early DENV-host interactions could facilitate a better understanding of viral tropism and pathogenesis to allow the development of new strategies for controlling DENV transmission.

  7. Gustatory receptor neuron responds to DEET and other insect repellents in the yellow fever mosquito, aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three gustatory receptor neurons were characterized for contact chemoreceptive sensilla on the labella of female yellow fever mosquitoes, Aedes aegypti. The neuron with the smallest amplitude spike responded to the feeding deterrent, quinine, as well as DEET and other insect repellents. Two other ...

  8. Physiological recordings and RNA sequencing of the gustatory appendages of the yellow-fever mosquito Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Electrophysiological recording of action potentials from sensory neurons of mosquitoes provides investigators a glimpse into the chemical perception of these disease vectors. We have recently identified a bitter sensing neuron in the labellum of female Aedes aegypti that responds to DEET and other ...

  9. Sialic Acid Expression in the Mosquito Aedes aegypti and Its Possible Role in Dengue Virus-Vector Interactions

    PubMed Central

    Cime-Castillo, Jorge; Delannoy, Philippe; Mendoza-Hernández, Guillermo; Monroy-Martínez, Verónica; Lanz-Mendoza, Humberto; Hernández-Hernández, Fidel de la Cruz; Cabello-Gutiérrez, Carlos; Ruiz-Ordaz, Blanca H.

    2015-01-01

    Dengue fever (DF) is the most prevalent arthropod-borne viral disease which affects humans. DF is caused by the four dengue virus (DENV) serotypes, which are transmitted to the host by the mosquito Aedes aegypti that has key roles in DENV infection, replication, and viral transmission (vector competence). Mosquito saliva also plays an important role during DENV transmission. In this study, we detected the presence of sialic acid (Sia) in Aedes aegypti tissues, which may have an important role during DENV-vector competence. We also identified genome sequences encoding enzymes involved in Sia pathways. The cDNA for Aedes aegypti CMP-Sia synthase (CSAS) was amplified, cloned, and functionally evaluated via the complementation of LEC29.Lec32 CSAS-deficient CHO cells. AedesCSAS-transfected LEC29.Lec32 cells were able to express Sia moieties on the cell surface. Sequences related to α-2,6-sialyltransferase were detected in the Aedes aegypti genome. Likewise, we identified Sia-α-2,6-DENV interactions in different mosquito tissues. In addition, we evaluated the possible role of sialylated molecules in a salivary gland extract during DENV internalization in mammalian cells. The knowledge of early DENV-host interactions could facilitate a better understanding of viral tropism and pathogenesis to allow the development of new strategies for controlling DENV transmission. PMID:25874215

  10. Complete Genome Sequence of Chikungunya Virus Isolated from an Aedes aegypti Mosquito during an Outbreak in Yemen, 2011

    PubMed Central

    Klena, John D.; Mohamed, Amr S.; Zayed, Alia; Villinski, Jeffrey T.

    2015-01-01

    Chikungunya virus is recognized as a serious public health problem. The complete genome was sequenced for a chikungunya virus isolated from the mosquito Aedes aegypti during a 2011 outbreak in Al Hodayda, Yemen, which resulted in significant human fatalities. Phylogenetic analysis demonstrated that this Yemeni isolate is most closely related to Indian Ocean strains of the east/central/south African genotype. PMID:26184944

  11. Diminished reproductive fitness associated with the deltamethrin resistance in an Indian strain of dengue vector mosquito, Aedes aegypti L.

    PubMed

    Kumar, Sarita; Thomas, Anita; Samuel, Thomas; Sahgal, Arunima; Verma, Anita; Pillai, M K K

    2009-08-01

    The susceptible (SS) and resistant (DLR) strains of Aedes aegypti selected with deltamethrin and combination of deltamethrin and PBO (1:5) at the larval/adult stage were studied in the laboratory for their reproductive fitness in terms of fecundity, hatchability and longevity of gonotrophic cycles. The DLR strains exhibited 73-88% reduction in the duration of gonotrophic cycles as compared to their SS counterparts. There was a considerable decrease in egg production and hatchability rates in the selected strains of Ae. aegypti, as compared to that of the SS strain. Data indicate deltamethrin being an effective insecticide against Ae. aegypti and a possible correlation between the deltamethrin resistance and disadvantages during reproduction. The most drastic and significant effect was observed in DLR1b strains exhibiting 36.7% decrease in fecundity and 32.4% reduction in hatchability. Another important observation was diminished reproductive fitness in DLR2 strains. This suggests the usefulness of synergized deltamethrin selections in reducing the frequency of resistant individuals. A significant finding was to observe the reproductive disadvantage in adult-selected strains having negligible resistance to deltamethrin implicating the efficacy of deltamethrin as an adulticide rather than as a larvicide. Various probable reasons for the reduction in the reproductive potential and the possible resistance-management strategies of Ae. aegypti are discussed.

  12. Effects of proteinase inhibitor from Adenanthera pavonina seeds on short- and long term larval development of Aedes aegypti.

    PubMed

    Sasaki, Daniele Yumi; Jacobowski, Ana Cristina; de Souza, Antônio Pancrácio; Cardoso, Marlon Henrique; Franco, Octávio Luiz; Macedo, Maria Lígia Rodrigues

    2015-05-01

    Currently, one of the major global public health concerns is related to the transmission of dengue/yellow fever virus by the vector Aedes aegypti. The most abundant digestive enzymes in Ae. aegypti midgut larvae are trypsin and chymotrypsin. Since protease inhibitors have the capacity to bind to and inhibit the action of insect digestive proteinases, we investigated the short- and long-term effects of Adenanthera pavonina seed proteinase inhibitor (ApTI) on Ae. aegypti larvae, as well as a possible mechanism of adaptation. ApTI had a significant effect on Ae. aegypti larvae exposed to a non-lethal concentration of ApTI during short- and long-duration assays, decreasing survival, weight and proteinase activities of midgut extracts of larvae. The zymographic profile of ApTI demonstrated seven bands; three bands apparently have trypsin-like activity. Moreover, the peritrophic membrane was not disrupted. The enzymes of ApTI-fed larvae were found to be sensitive to ApTI and to have a normal feedback mechanism; also, the larval digestive enzymes were not able to degrade the inhibitor. In addition, ApTI delayed larval development time. Histological studies demonstrated a degeneration of the microvilli of the posterior midgut region epithelium cells, hypertrophy of the gastric caeca cells and an augmented ectoperitrophic space in larvae. Moreover, Ae. aegypti larvae were incapable of overcoming the negative effects of ApTI, indicating that this inhibitor might be used as a promising agent against Ae. aegypti. In addition, molecular modeling and molecular docking studies were also performed in order to construct three-dimensional theoretical models for ApTI, trypsin and chymotrypsin from Ae. aegypti, as well as to predict the possible interactions and affinity values for the complexes ApTI/trypsin and ApTI/chymotrypsin. In this context, this study broadens the base of our understanding about the modes of action of proteinase inhibitors in insects, as well as the way insects

  13. Transcriptome Sequencing Reveals Large-Scale Changes in Axenic Aedes aegypti Larvae

    PubMed Central

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

    2017-01-01

    Mosquitoes host communities of microbes in their digestive tract that consist primarily of bacteria. We previously reported that Aedes aegypti larvae colonized by a native community of bacteria and gnotobiotic larvae colonized by only Escherichia coli develop very similarly into adults, whereas axenic larvae never molt and die as first instars. In this study, we extended these findings by first comparing the growth and abundance of bacteria in conventional, gnotobiotic, and axenic larvae during the first instar. Results showed that conventional and gnotobiotic larvae exhibited no differences in growth, timing of molting, or number of bacteria in their digestive tract. Axenic larvae in contrast grew minimally and never achieved the critical size associated with molting by conventional and gnotobiotic larvae. In the second part of the study we compared patterns of gene expression in conventional, gnotobiotic and axenic larvae by conducting an RNAseq analysis of gut and nongut tissues (carcass) at 22 h post-hatching. Approximately 12% of Ae. aegypti transcripts were differentially expressed in axenic versus conventional or gnotobiotic larvae. However, this profile consisted primarily of transcripts in seven categories that included the down-regulation of select peptidases in the gut and up-regulation of several genes in the gut and carcass with roles in amino acid transport, hormonal signaling, and metabolism. Overall, our results indicate that axenic larvae exhibit alterations in gene expression consistent with defects in acquisition and assimilation of nutrients required for growth. PMID:28060822

  14. Evaluation of novel insecticides for control of dengue vector Aedes aegypti (Diptera: Culicidae).

    PubMed

    Paul, Ayesa; Harrington, Laura C; Scott, Jeffrey G

    2006-01-01

    Insecticides are one of the major tools for controlling vector populations and for reducing the transmission of human pathogens. However, there are few new insecticides being developed and marketed for vector control. Herein, we report on the toxicity of six novel insecticides to both adult and larval Aedes aegypti (L). and the toxicity of three novel insect growth regulators (IGRs) to larvae. Four insecticides were highly or moderately toxic to larvae with LC50 values of 16 (chlorfenapyr), 70 (hydramethylnon), 79 (indoxacarb), and 84 ng/ml (imidacloprid). Diafenthiuron and chlorfenapyr were moderately toxic to adult mosquitoes with LC50 values of 13 and 92 ng/cm2, respectively. Imidacloprid was strongly synergized by piperonyl butoxide (PBO) in Ae. aegypti adults, suggesting that neonicotinoids are intrinsically very toxic to adult mosquitoes (in the absence of detoxification). The effect of PBO on the toxicity in adults and larvae was considerably different, both in terms of the insecticides that were synergized (or antagonized for chlorfenapyr versus adults) and in terms of the degree of synergism. This result implies that the cytochrome P450s involved in metabolism of these insecticides are different between adults and larvae. Pyriproxyfen was confirmed as a potent IGR (EC50 of 0.0017 ng/ml) for mosquitoes, although tebufenozide lacked activity. The potential for use of these materials in mosquito control is discussed.

  15. Comparing dengue and chikungunya emergence and endemic transmission in A. aegypti and A. albopictus

    PubMed Central

    Manore, Carrie A.; Hickmann, Kyle S.; Xu, Sen; Wearing, Helen J.; Hyman, James M.

    2014-01-01

    Chikungunya and dengue are re-emerging mosquito-borne infectious diseases that are of increasing concern as human travel and expanding mosquito ranges increase the risk of spread. We seek to understand the differences in transient and endemic behavior of chikungunya and dengue; risk of emergence for different virus-vector assemblages; and the role that virus evolution plays in disease dynamics and risk. To address these questions, we adapt a mathematical mosquito-borne disease model to chikungunya and dengue in Aedes aegypti and Aedes albopictus mosquitoes. We derive analytical threshold conditions and important dimensionless parameters for virus transmission; perform sensitivity analysis on quantities of interest such as the basic reproduction number, endemic equilibrium, and first epidemic peak; and compute distributions for the quantities of interest across parameter ranges. We found that chikungunya and dengue exhibit different transient dynamics and long-term endemic levels. While the order of most sensitive parameters is preserved across vector-virus combinations, the magnitude of sensitivity is different across scenarios, indicating that risk of invasion or an outbreak can change with vector-virus assemblages. We found that the dengue-A. aegypti and new Rèunion strain of chikungunya-A. albopictus systems represent the highest risk across the range of parameters considered. These results inform future experimental and field research efforts and point toward effective mitigation strategies adapted to each disease. PMID:24801860

  16. Sub-lethal metal stress response of larvae of Aedes aegypti.

    PubMed

    Perez, Mario H; Noriega, Fernando G

    2014-06-01

    Aedes aegypti (Diptera: Culicidae) has adapted to urban environments; the urbanisation process provides suitable habitats for this disease vector subsequently increasing the probability of the transmission of pathogens in high-density environments. Urban environments provide metal stressed larval habitats. However, little is known about the physiological cost of metal stress or how this might affect the performance of this mosquito species. This study aims to characterise the sub-lethal physiological consequences of metal stress in Aedes aegypti. Various parameters of mosquito physiology under larval metal stress are assessed including larval metallothionein expression and the effects of larval metal stress on adult performance and their progeny. Results show that environmentally relevant larval metal stress compromises larval and adult development and performance, and results in larval metal tolerance along with an increase in lipid consumption. These performance costs are coupled to a dramatic increase in metallothionein expression in the midgut. Metal stress results in lowered adult body mass and neutral storage lipids at emergence, starvation tolerance, fecundity and starvation tolerance of offspring compared to non-metal stressed individuals. Ironically, larval metal stress results in increased adult longevity. Together, these findings indicate that even low levels of environmentally relevant larval metal stress have considerable physiological consequences for this important disease vector.

  17. Aedes aegypti pharate 1st instar quiescence: a case for anticipatory reproductive plasticity.

    PubMed

    Perez, Mario H; Noriega, Fernando G

    2013-03-01

    Aedes aegypti mosquitoes use pharate 1st instar quiescence to cope with fluctuations in water availability hosting a fully developed 1st instar larvae within the chorion. The duration of this quiescence has been shown to affect larval fitness. This study sought to determine if an extended egg quiescence can elicit a plastic response resulting in an adult phenotype distinct from adults reared from short quiescence eggs. Our findings indicate that extended pharate 1st instar quiescence affects the performance and reproductive fitness of the adult female mosquito as well as the nutritional status of its progeny via maternal effects in an adaptive manner. This study demonstrates that phenotypic plasticity results as a consequence of the duration of pharate 1st instar quiescence and alternative phenotypes may exist for this mosquito with quiescence serving as a cue possibly signaling the environmental conditions that follow a dry period. These findings have implications for A. aegypti's success as a vector, geographic distribution, vector capacity and control.

  18. Mechanisms of insecticide resistance in field populations of Aedes aegypti (L.) from Quintana Roo, Southern Mexico.

    PubMed

    Flores, Adriana E; Grajales, Jaime Salomon; Salas, Ildefonso Fernandez; Garcia, Gustavo Ponce; Becerra, Ma Haydee Loaiza; Lozano, Saul; Brogdon, William G; Black, William C; Beaty, Barry

    2006-12-01

    Potential insecticide-resistance mechanisms were studied with the use of biochemical assays in Aedes aegypti (L.) collected from 5 municipalities representing the north part of Quintana Roo: Benito Juarez, Cozumel, Isla Mujeres, Lazaro Cardenas, and Solidaridad. The activities of alpha and beta esterases, mixed-function oxidases (MFO), glutathione-S-transferase (GST), acethylcholinesterase (AChE), and insensitive acethylcholinesterase (iAChE) were assayed in microplates. Three replicates were performed for each enzyme and 60 males and 60 females were analyzed in each population. The New Orleans (NO) susceptible strain of Ae. aegypti was used as a susceptible reference and the threshold criteria for each enzyme were the highest NO absorbance values. In none of the 6 tests were absorbance values correlated in males and females. alpha esterases were elevated in Benito Juarez, Cozumel females and in Lazaro Cardenas males and females. beta esterases were elevated in Benito Juarez, Cozumel females and in Cozumel and Lazaro Cardenas males. Elevated esterases suggest potential insecticide-resistance mechanisms against organophosphate, carbamate, and some pyrethroid insecticides. Slightly elevated levels of MFOs appeared in Lazaro Cardenas females and in Cozumel, Isla Mujeres, and Solidaridad males. Mechanisms involving iAChE or GST were not apparent.

  19. Socioeconomic and Ecological Factors Influencing Aedes aegypti Prevalence, Abundance, and Distribution in Dhaka, Bangladesh.

    PubMed

    Dhar-Chowdhury, Parnali; Haque, C Emdad; Lindsay, Robbin; Hossain, Shakhawat

    2016-06-01

    This study examined household risk factors and prevalence, abundance, and distribution of immature Aedes aegypti and Aedes albopictus, and their association with socioeconomic and ecological factors at urban zonal and household levels in the city of Dhaka, Bangladesh. During the 2011 monsoon, 826 households in 12 randomly selected administrative wards were surveyed for vector mosquitoes. Results revealed that the abundance and distribution of immature Ae. aegypti and Ae. albopictus, and pupae-per-person indices did not vary significantly among the zones with varied socioeconomic status. Of 35 different types of identified wet containers, 30 were infested, and among the 23 pupae-positive container types, nine were defined as the "most productive" for pupae including: disposable plastic containers (12.2% of 550), sealable plastic barrels (12.0%), tires (10.4%), abandoned plastic buckets (9.6%), flower tub and trays (8.5%), refrigerator trays (6.5%), plastic bottles (6.4%), clay pots (4.9%), and water tanks (1.6%). When the function of the containers was assessed, ornamental, discarded, and household repairing and reconstruction-related container categories were found significantly associated with the number of pupae in the households. The purpose of storing water and income variables were significant predictors of possession of containers that were infested by vector mosquitoes.

  20. Susceptibility to Chlorpyrifos in Pyrethroid-Resistant Populations of Aedes aegypti (Diptera: Culicidae) from Mexico

    PubMed Central

    Lopez, Beatriz; Ponce, Gustavo; Gonzalez, Jessica A.; Gutierrez, Selene M.; Villanueva, Olga K.; Gonzalez, Gabriela; Bobadilla, Cristina; Rodriguez, Iram P.; Black, William C.; Flores, Adriana E.

    2014-01-01

    Resistance to the organophosphate insecticide chlorpyrifos was evaluated in females from six strains of Aedes aegypti (L) that expressed high levels of cross resistance to eight pyrethroid insecticides. Relative to LC50 and LC90 at 24h of a susceptible New Orleans (NO) three strains were highly resistant to chlorpyrifos (Coatzacoalcos, resistance ratio (RRLC90) =11.97; Pozarica, RRLC90=12.98; and Cosoleacaque, RRLC50= 13.94 and RRLC90=17.57), one strain was moderately resistant (Veracruz, RR=5.92), and two strains were susceptible (Tantoyuca and Martinez de la Torre, RRLC50 and RRLC90 < 5) in CDC bottle bioassays. Furthermore, high levels of α/β-esterase activity in the sample populations were correlated with resistance, suggesting that esterase activity may be a mechanism causing the development of organophosphate resistance in these populations. Overall, the populations in this study were less resistant to chlorpyrifos than to pyrethroids. Rotation of insecticides used in control activities is recommended to delay or minimize the occurrence of high levels of resistance to chlorpyrifos among local populations of Ae. aegypti. The diagnostic dose (DD) and diagnostic time (DT) for chlorpyrifos resistance monitoring was determined to be 85 μg/ bottle and 30min, respectively, using the susceptible NO strain. PMID:24897857

  1. Resistance Status to the Insecticides Temephos, Deltamethrin, and Diflubenzuron in Brazilian Aedes aegypti Populations

    PubMed Central

    Viana-Medeiros, Priscila Fernandes; Araújo, Simone Costa; Martins, Ademir J.; Lima, José Bento Pereira

    2016-01-01

    Insecticides are still largely applied in public health to control disease vectors. In Brazil, organophosphates (OP) and pyrethroids (PY) are used against Aedes aegypti for years. Since 2009 Insect Growth Regulators (IGR) are also employed in the control of larvae. We quantified resistance to temephos (OP), deltamethrin (PY), and diflubenzuron (IGR) of A. aegypti samples from 12 municipalities distributed throughout the country, collected between 2010 and 2012. High levels of resistance to neurotoxic insecticides were detected in almost all populations: RR95 to temephos varied between 4.0 and 27.1; the lowest RR95 to deltamethrin was 13.1, and values higher than 70.0 were found. In contrast, all samples were susceptible to diflubenzuron (RR95 < 2.3). Biochemical tests performed with larvae and adults discarded the participation of acetylcholinesterase, the OP target, and confirmed involvement of the detoxifying enzymes esterases, mixed function oxidases, and glutathione-S-transferases. The results obtained were discussed taking into account the public chemical control component and the increase in the domestic use of insecticides during dengue epidemic seasons in the evaluated municipalities. PMID:27419140

  2. Circadian clock of Aedes aegypti: effects of blood-feeding, insemination and RNA interference

    PubMed Central

    Gentile, Carla; Rivas, Gustavo Bueno da S; Lima, José BP; Bruno, Rafaela Vieira; Peixoto, Alexandre Afranio

    2013-01-01

    Mosquitoes are the culprits of some of the most important vector borne diseases. A species’ potential as a vector is directly dependent on their pattern of behaviour, which is known to change according to the female’s physiological status such as whether the female is virgin/mated and unfed/blood-fed. However, the molecular mechanism triggered by and/or responsible for such modulations in behaviour is poorly understood. Clock genes are known to be responsible for the control of circadian behaviour in several species. Here we investigate the impact mating and blood-feeding have upon the expression of these genes in the mosquito Aedes aegypti . We show that blood intake, but not insemination, is responsible for the down-regulation of clock genes. Using RNA interference, we observe a slight reduction in the evening activity peak in the fourth day after dstim injection. These data suggest that, as in Drosophila , clock gene expression, circadian behaviour and environmental light regimens are interconnected in Ae. aegypti . PMID:24473806

  3. Analysis of cycle Gene Expression in Aedes aegypti Brains by In Situ Hybridization

    PubMed Central

    Chahad-Ehlers, Samira; Gentile, Carla; Lima, José Bento Pereira; Peixoto, Alexandre Afranio; Bruno, Rafaela Vieira

    2013-01-01

    Even though the blood-sucking mosquito Aedes aegypti is one of the most important disease vectors, relatively little is known about the molecular mechanisms underlying processes involved in the temporal pattern of its activity and host seeking behavior. In this study, we analyzed the expression of the cycle (cyc) gene, one of the core components of the circadian clock, in Ae. aegypti brains by in situ hybridization at two different time points in light-dark conditions and compared the results with those obtained using a quantitative PCR assay (qPCR). Within the brain, differential labeling was detected according to distinct areas empirically pre-defined. Six out of seven of these areas showed significantly higher staining at ZT3 (three hours after light-on) compared to ZT11 (one before light-off), which is consistent with the qPCR data. Predominant staining was observed in three of those areas which correspond to positions of the optical and antennal lobes, as well as the region where the neurons controlling activity rhythms are presumably localized. PMID:23300979

  4. Wolbachia Infections in Aedes aegypti Differ Markedly in Their Response to Cyclical Heat Stress

    PubMed Central

    Wiwatanaratanabutr, Itsanun; White, Vanessa L.; Hoffmann, Ary A.

    2017-01-01

    Aedes aegypti mosquitoes infected with Wolbachia bacteria are currently being released for arbovirus suppression around the world. Their potential to invade populations and persist will depend on interactions with environmental conditions, particularly as larvae are often exposed to fluctuating and extreme temperatures in the field. We reared Ae. aegypti larvae infected with different types of Wolbachia (wMel, wAlbB and wMelPop-CLA) under diurnal cyclical temperatures. Rearing wMel and wMelPop-CLA-infected larvae at 26–37°C reduced the expression of cytoplasmic incompatibility, a reproductive manipulation induced by Wolbachia. We also observed a sharp reduction in the density of Wolbachia in adults. Furthermore, the wMel and wMelPop-CLA infections were not transmitted to the next generation when mosquitoes were exposed to 26–37°C across all life stages. In contrast, the wAlbB infection was maintained at a high density, exhibited complete cytoplasmic incompatibility, and was transmitted from mother to offspring with a high fidelity under this temperature cycle. These findings have implications for the potential success of Wolbachia interventions across different environments and highlight the importance of temperature control in rearing. PMID:28056065

  5. Persistence of dengue virus RNA in dried Aedes aegypti (Diptera: Culicidae) exposed to natural tropical conditions.

    PubMed

    Bangs, Michael J; Pudiantari, Ratna; Gionar, Yoyo R

    2007-01-01

    Aedes aegypti (L.) is the primary vector of dengue viruses, a group of four serotypic single-stranded RNA viruses. Dengue virus RNA can be readily detected in fresh or dried infected mosquitoes by using reverse transcriptase-polymerase chain reaction (RT-PCR). The current study examined the persistence and limit of dengue virus RNA detection in infected Ae. aegypti killed and exposed to natural ambient tropical conditions of temperature and humidity. Under relatively harsh conditions, dengue RNA retained sufficient integrity to be detected in dried mosquitoes up to 13 wk after exposure to relatively high ambient temperatures (26.3-31.7 degrees C) and relative humidity (49.4-69.9%). These findings confirm that the necessity for testing either fresh or frozen mosquitoes is not a prerequisite when using RT-PCR as the viral detection method, and under particular epidemiological circumstances it allows for a more convenient means of conducting vector-virus surveillance activities where collection methods and logistics may preclude immediate testing or access to a cold chain.

  6. Rhodopsin coexpression in UV photoreceptors of Aedes aegypti and Anopheles gambiae mosquitoes.

    PubMed

    Hu, Xiaobang; Leming, Matthew T; Whaley, Michelle A; O'Tousa, Joseph E

    2014-03-15

    Differential rhodopsin gene expression within specialized R7 photoreceptor cells divides the retinas of Aedes aegypti and Anopheles gambiae mosquitoes into distinct domains. The two species express the rhodopsin orthologs Aaop8 and Agop8, respectively, in a large subset of these R7 photoreceptors that function as ultraviolet receptors. We show here that a divergent subfamily of mosquito rhodopsins, Aaop10 and Agop10, is coexpressed in these R7 photoreceptors. The properties of the A. aegypti Aaop8 and Aaop10 rhodopsins were analyzed by creating transgenic Drosophila expressing these rhodopsins. Electroretinogram recordings, and spectral analysis of head extracts, obtained from the Aaop8 strain confirmed that Aaop8 is an ultraviolet-sensitive rhodopsin. Aaop10 was poorly expressed and capable of eliciting only small and slow light responses in Drosophila photoreceptors, and electroretinogram analysis suggested that it is a long-wavelength rhodopsin with a maximal sensitivity near 500 nm. Thus, coexpression of Aaop10 rhodopsin with Aaop8 rhodopsin has the potential to modify the spectral properties of mosquito ultraviolet receptors. Retention of Op10 rhodopsin family members in the genomes of Drosophila species suggests that this rhodopsin family may play a conserved role in insect vision.

  7. Aedes aegypti larvicide from the ethanolic extract of Piper nigrum black peppercorns.

    PubMed

    Santiago, Viviene S; Alvero, Rita Grace; Villaseñor, Irene M

    2015-01-01

    Due to unavailability of a vaccine and a specific cure to dengue, the focus nowadays is to develop an effective vector control method against the female Aedes aegypti mosquito. This study aims to determine the larvicidal fractions from Piper nigrum ethanolic extracts (PnPcmE) and to elucidate the identity of the bioactive compounds that comprise these larvicidal fractions. Larvicidal assay was performed by subjecting 3rd to 4th A. aegypti instar larvae to PnPcmE of P. nigrum. The PnPcmE exhibited potential larvicidal activity having an LC50 of 7.1246 ± 0.1304 ppm (mean ± Std error). Normal phase vacuum liquid chromatography of the PnPcmE was employed which resulted in five fractions, two of which showed larvicidal activity. The most active of the PnPcmE fractions is PnPcmE-1A, with an LC50 and LC90 of 1.7101 ± 0.0491 ppm and 3.7078 ppm, respectively. Subsequent purification of PnPcmE-1A allowed the identification of the larvicidal compound as oleic acid.

  8. Essential oils enhance the toxicity of permethrin against Aedes aegypti and Anopheles gambiae.

    PubMed

    Gross, A D; Norris, E J; Kimber, M J; Bartholomay, L C; Coats, J R

    2017-03-01

    Insecticide resistance and growing public concern over the safety and environmental impacts of some conventional insecticides have resulted in the need to discover alternative control tools. Naturally occurring botanically-based compounds are of increased interest to aid in the management of mosquitoes. Susceptible strains of Aedes aegypti (Linnaeus) (Diptera: Culicidae) and Anopheles gambiae (Meigen) (Diptera: Culicidae) were treated with permethrin, a common type-I synthetic pyrethroid, using a discriminate dose that resulted in less than 50% mortality. Piperonyl butoxide (PBO) and 35 essential oils were co-delivered with permethrin at two doses (2 and 10 µg) to determine if they could enhance the 1-h knockdown and the 24-h mortality of permethrin. Several of the tested essential oils enhanced the efficacy of permethrin equally and more effectively than piperonyl butoxide PBO, which is the commercial standard to synergize chemical insecticide like pyrethroids. PBO had a strikingly negative effect on the 1-h knockdown of permethrin against Ae. aegypti, which was not observed in An. gambiae. Botanical essential oils have the capability of increasing the efficacy of permethrin allowing for a natural alternative to classic chemical synergists, like PBO.

  9. Salinity responsive aquaporins in the anal papillae of the larval mosquito, Aedes aegypti.

    PubMed

    Akhter, Hina; Misyura, Lidiya; Bui, Phuong; Donini, Andrew

    2017-01-01

    The larvae of the mosquito, Aedes aegypti normally inhabit freshwater (FW) where they face dilution of body fluids by osmotic influx of water. In response, the physiological actions of the anal papillae result in ion uptake while the Malpighian tubules and rectum work in concert to excrete excess water. In an apparent paradox, the anal papillae express aquaporins (AQPs) and are sites of water permeability which, if AQPs are expressed by the epithelium, apparently exaggerates the influx of water from their dilute environment. Recently, naturally breeding populations of A. aegypti were found in brackish water (BW), an environment which limits the osmotic gradient. Given that salinization of FW is an emerging environmental issue and that these larvae would presumably need to adjust to these changing conditions, this study investigates the expression of AQPs in the anal papillae and their response to rearing in hypo-osmotic and near isosmotic conditions. Transcripts of all six Aedes AQP homologs were detectable in the anal papillae and the transcript abundance of three AQP homologs in the papillae was different between rearing conditions. Using custom made antibodies, expression of two of these AQP homologs (AQP4 and AQP5) was localized to the syncytial epithelium of the anal papillae. Furthermore, the changes in transcript abundance of these two AQPs between the rearing conditions, were manifested at the protein level. Results suggest that AQP4 and AQP5 play an important physiological role in larval responses to changes in environmental salinity.

  10. Using Wolbachia Releases to Estimate Aedes aegypti (Diptera: Culicidae) Population Size and Survival

    PubMed Central

    Garcia, Gabriela de Azambuja; dos Santos, Lilha Maria Barbosa; Villela, Daniel Antunes Maciel; Maciel-de-Freitas, Rafael

    2016-01-01

    Mosquitoes carrying the endosymbiont bacterium Wolbachia have been deployed in field trials as a biological control intervention due to Wolbachia effects on reducing transmission of arboviruses. We performed mark, release and recapture (MRR) experiments using Wolbachia as an internal marker with daily collections with BG-Traps during the first two weeks of releases in Rio de Janeiro, Brazil. The MRR design allowed us to investigate two critical parameters that determine whether Wolbachia would successful invade a field population: the probability of daily survival (PDS) of Wolbachia-infected Aedes aegypti females, and the wild population density during releases. Released females had a PDS of 0.82 and 0.89 in the first and second weeks, respectively, immediately after releases, which is well within the range of previous estimates of survivorship of wild mosquitoes in Rio de Janeiro. Abundance estimation of wild population varied up to 10-fold higher depending on the estimation method used (634–3565 females on the average-difference model to 6365–16188 females according to Lincoln-Petersen). Wolbachia-released mosquitoes were lower than the density estimation of their wild counterparts, irrespectively of the model used. Individually screening mosquitoes for the presence of Wolbachia reduced uncertainty on abundance estimations due to fluctuation in capturing per week. A successful invasion into local population requires Ae. aegypti fitness is unaffected by Wolbachia presence, but also reliable estimates on the population size of wild mosquitoes. PMID:27479050

  11. Wolbachia Infections in Aedes aegypti Differ Markedly in Their Response to Cyclical Heat Stress.

    PubMed

    Ross, Perran A; Wiwatanaratanabutr, Itsanun; Axford, Jason K; White, Vanessa L; Endersby-Harshman, Nancy M; Hoffmann, Ary A

    2017-01-01

    Aedes aegypti mosquitoes infected with Wolbachia bacteria are currently being released for arbovirus suppression around the world. Their potential to invade populations and persist will depend on interactions with environmental conditions, particularly as larvae are often exposed to fluctuating and extreme temperatures in the field. We reared Ae. aegypti larvae infected with different types of Wolbachia (wMel, wAlbB and wMelPop-CLA) under diurnal cyclical temperatures. Rearing wMel and wMelPop-CLA-infected larvae at 26-37°C reduced the expression of cytoplasmic incompatibility, a reproductive manipulation induced by Wolbachia. We also observed a sharp reduction in the density of Wolbachia in adults. Furthermore, the wMel and wMelPop-CLA infections were not transmitted to the next generation when mosquitoes were exposed to 26-37°C across all life stages. In contrast, the wAlbB infection was maintained at a high density, exhibited complete cytoplasmic incompatibility, and was transmitted from mother to offspring with a high fidelity under this temperature cycle. These findings have implications for the potential success of Wolbachia interventions across different environments and highlight the importance of temperature control in rearing.

  12. Efficacy of photodynamic therapy against larvae of Aedes aegypti: confocal microscopy and fluorescence-lifetime imaging

    NASA Astrophysics Data System (ADS)

    de Souza, L. M.; Pratavieira, S.; Inada, N. M.; Kurachi, C.; Corbi, J.; Guimarães, F. E. G.; Bagnato, V. S.

    2014-03-01

    Recently a few demonstration on the use of Photodynamic Reaction as possibility to eliminate larvae that transmit diseases for men has been successfully demonstrated. This promising tool cannot be vastly used due to many problems, including the lake of investigation concerning the mechanisms of larvae killing as well as security concerning the use of photosensitizers in open environment. In this study, we investigate some of the mechanisms in which porphyrin (Photogem) is incorporated on the Aedes aegypti larvae previously to illumination and killing. Larvae at second instar were exposed to the photosensitizer and after 30 minutes imaged by a confocal fluorescence microscope. It was observed the presence of photosensitizer in the gut and at the digestive tract of the larva. Fluorescence-Lifetime Imaging showed greater photosensitizer concentration in the intestinal wall of the samples, which produces a strong decrease of the Photogem fluorescence lifetime. For Photodynamic Therapy exposition to different light doses and concentrations of porphyrin were employed. Three different light sources (LED, Fluorescent lamp, Sun light) also were tested. Sun light and fluorescent lamp shows close to 100% of mortality after 24 hrs. of illumination. These results indicate the potential use of photodynamic effect against the LARVAE of Aedes aegypti.

  13. Transcriptome Sequencing Reveals Large-Scale Changes in Axenic Aedes aegypti Larvae.

    PubMed

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

    2017-01-01

    Mosquitoes host communities of microbes in their digestive tract that consist primarily of bacteria. We previously reported that Aedes aegypti larvae colonized by a native community of bacteria and gnotobiotic larvae colonized by only Escherichia coli develop very similarly into adults, whereas axenic larvae never molt and die as first instars. In this study, we extended these findings by first comparing the growth and abundance of bacteria in conventional, gnotobiotic, and axenic larvae during the first instar. Results showed that conventional and gnotobiotic larvae exhibited no differences in growth, timing of molting, or number of bacteria in their digestive tract. Axenic larvae in contrast grew minimally and never achieved the critical size associated with molting by conventional and gnotobiotic larvae. In the second part of the study we compared patterns of gene expression in conventional, gnotobiotic and axenic larvae by conducting an RNAseq analysis of gut and nongut tissues (carcass) at 22 h post-hatching. Approximately 12% of Ae. aegypti transcripts were differentially expressed in axenic versus conventional or gnotobiotic larvae. However, this profile consisted primarily of transcripts in seven categories that included the down-regulation of select peptidases in the gut and up-regulation of several genes in the gut and carcass with roles in amino acid transport, hormonal signaling, and metabolism. Overall, our results indicate that axenic larvae exhibit alterations in gene expression consistent with defects in acquisition and assimilation of nutrients required for growth.

  14. Oviposition Habitat Selection of Dengue Vectors, Aedes aegypti and Aedes albopictus in Response to Fish Predator

    PubMed Central

    Zuharah, Wan Fatma; Fadzly, Nik; Wei, Wilson Ong Kang; Hashim, Zarul Hazrin

    2016-01-01

    To understand the effects of fish predator’s kairomones on Aedes mosquitoes’ oviposition, we established an experiment using gravid Aedes females. Kairomones concentrations were established using Hampala macrolepidota. One individual fish was placed inside containers with varying water levels (1 L, 5 L, and 10 L of water). The fish were kept in the containers for 24 hours and were removed immediately at the start of each trial in order to have the kairomones remnants. Twenty gravid adult females of Aedes aegypti and Aedes albopictus were allowed to lay eggs on oviposition site with various treatments: (1) control without any kairomones; (2) kairomone remnant in 1 L of water; (3) kairomone remnant in 5 L of water; and (4) kairomone remnant in 10 L of water. There are significant differences between the numbers of eggs laid by both Aedes species for each different treatment (F = 9.131, df = 16, p<0.001). However, fewer eggs were laid by Ae. albopictus compared to Ae. aegypti in the presence of kairomone remnants. This suggested that Ae. albopictus are significantly affected by the kairomones itself and have ability to detect the residual kairomone presence from H. macrolepidota. PMID:27965749

  15. Aedes aegypti Rhesus glycoproteins contribute to ammonia excretion by larval anal papillae.

    PubMed

    Durant, Andrea C; Chasiotis, Helen; Misyura, Lidiya; Donini, Andrew

    2017-02-15

    In larval Aedes aegypti, transcripts of the Rhesus-like glycoproteins AeRh50-1 and AeRh50-2 have been detected in the anal papillae, sites of ammonia (NH3/NH4(+)) excretion; however, these putative ammonia transporters have not been previously localized or functionally characterized. In this study, we show that the AeRh50s co-immunolocalize with apical V-type H(+)-ATPase as well as with basal Na(+)/K(+)-ATPase in the epithelium of anal papillae. The double-stranded RNA-mediated knockdown of AeRh50-1 and AeRh50-2 resulted in a significant reduction in AeRh50 protein abundance in the anal papillae, and this was coupled to decreased ammonia excretion. The knockdown of AeRh50-1 resulted in decreased hemolymph [NH4(+)] and pH whereas knockdown of AeRh50-2 had no effect on these parameters. We conclude that the AeRh50s are important contributors to ammonia excretion at the anal papillae of larval A. aegypti, which may be the basis for their ability to inhabit areas with high ammonia levels.

  16. Efficacy of 4-methyl-7-hydroxy coumarin derivatives against vectors Aedes aegypti and Culex quinquefasciatus.

    PubMed

    Deshmukh, Madhavi; Pawar, Pushpa; Joseph, Mary; Phalgune, Usha; Kashalkar, Rajashree; Deshpande, Nirmala R

    2008-11-01

    4-Methyl-7-hydroxy coumarin is considered as a lead molecule as a biopesticide. Its mono bromo and tribromo derivatives were synthesized. Two more derivatives were synthesized by acylation. Compound 1 (3,6,8-tribromo-7-hydroxy-4-methyl-chromen-2-one) was found to be the most potent against IVth instar larvae of C. quinquefasciatus and A. aegypti the LC50 being 1.49 and 2.23 ppm respectively. It showed 100% larval mortality at 25 ppm against A. aegypti and at 10 ppm against C. quinquefasciatus. Compounds 1 and 2 (3,6,8-tribromo-7-hydroxy-4-methyl-chromen-2'-oxo-2H-chromen-7-yl acetate) showed remarkable ovicidal activity. Significant reduction of 80-85% hatching of eggs of both mosquito species was observed at the highest dose of 100 ppm. The hatched larvae showed 100% mortality in the successive instars. Compounds 3 and 4 (3-bromo-7-hydroxy-4-methyl-chromen-2-one and 3-bromo-4-methyl-2'-oxo-2H-chromen-7-yl acetate) showed moderate activity against both mosquito species.

  17. Proteomic Identification of Dengue Virus Binding Proteins in Aedes aegypti Mosquitoes and Aedes albopictus Cells

    PubMed Central

    Muñoz, Maria de Lourdes; Limón-Camacho, Gustavo; Tovar, Rosalinda; Diaz-Badillo, Alvaro; Mendoza-Hernández, Guillermo; Black, William C.

    2013-01-01

    The main vector of dengue in America is the mosquito Aedes aegypti, which is infected by dengue virus (DENV) through receptors of midgut epithelial cells. The envelope protein (E) of dengue virus binds to receptors present on the host cells through its domain III that has been primarily recognized to bind cell receptors. In order to identify potential receptors, proteins from mosquito midgut tissue and C6/36 cells were purified by affinity using columns with the recombinant E protein domain III (rE-DIII) or DENV particles bound covalently to Sepharose 4B to compare and evaluate their performance to bind proteins including putative receptors from female mosquitoes of Ae. aegypti. To determine their identity mass spectrometric analysis of purified proteins separated by polyacrylamide gel electrophoresis was performed. Our results indicate that both viral particles and rE-DIII bound proteins with the same apparent molecular weights of 57 and 67 kDa. In addition, viral particles bound high molecular weight proteins. Purified proteins identified were enolase, beta-adrenergic receptor kinase (beta-ARK), translation elongation factor EF-1 alpha/Tu, and cadherin. PMID:24324976

  18. Productive container types for Aedes aegypti immatures in Mérida, México.

    PubMed

    García-Rejón, Julian E; López-Uribe, Mildred P; Loroño-Pino, María Alba; Farfán-Ale, José Arturo; Del Najera-Vazquez, Maria Rosario; Lozano-Fuentes, Saul; Beaty, Barry J; Eisen, Lars

    2011-05-01

    During 2007-2010, we examined which container types in Mérida, México, are most productive for Aedes aegypti (L.) immatures. Surveys for mosquito immatures followed routine surveillance methodology and container type classifications used by Servicios de Salud de Yucatán. Our main findings were that (1) small and larger discarded containers that serve no particular purpose and therefore can be removed from the environment contribute strongly to larval and pupal production in Mérida, and (2) the importance of different container types can vary among sets of residential premises as well as between dry and wet periods. These results may help to guide future implementation in Mérida of control efforts that target the most productive container types for Ae. aegypti immatures. Furthermore, if the Patio Limpio cleanup campaign that currently is ongoing in Mérida proves successful in removing discarded containers as important immature development sites, then we should see dramatic changes in the most productive container types in the future as the mosquito is forced to switch to other container types, which perhaps also will be easier to include in highly targeted mosquito control interventions.

  19. Polyandry Depends on Postmating Time Interval in the Dengue Vector Aedes aegypti

    PubMed Central

    Degner, Ethan C.; Harrington, Laura C.

    2016-01-01

    Aedes aegypti is the primary vector of the dengue and chikungunya viruses. After mating, male seminal fluid molecules cause females to become unreceptive to a subsequent mating. This response is often assumed to be immediate and complete, but a growing body of evidence suggests that some females do mate more than once. It is unknown how quickly a female becomes unreceptive to a second mating. Furthermore, the degree to which she remains monandrous after laying several batches of eggs has not been rigorously tested. Therefore, we assessed the rates of polyandry in two sets of experiments using wild-type males and those with fluorescent sperm. The first experiment tested the likelihood of polyandry after postmating intervals of various durations. Most females became refractory to a second mating within 2 hours after mating, and rates of polyandry ranged from 24% immediately after mating to 3% at 20 hours after mating. The second experiment tested whether females were polyandrous after cycles of blood meals and oviposition. No re-insemination was found after one, three, or five such cycles. This study is the first to demonstrate that polyandrous behavior depends on the postmating interval. Our results will inform future applications that depend on an accurate knowledge of Ae. aegypti mating behavior, including models of gene flow, investigations of molecules that drive female mating behavior, and control strategies that deploy genetically modified mosquitoes into the field. PMID:26880776

  20. Feeding deterrent effects of catnip oil components compared with two synthetic amides against Aedes aegypti.

    PubMed

    Chauhan, Kamlesh R; Klun, Jerome A; Debboun, Mustapha; Kramer, Matthew

    2005-07-01

    Recently, catnip, Nepeta cataria L. (Lamiaceae), essential oil has been formulated and marketed as an alternative repellent for protection against biting arthropods by several vendors. We isolated the major active components of catnip oil, E,Z- and Z,E-nepetalactone, and quantitatively measured their antibiting efficacy compared with the repellents N,N-diethyl-3-methylbenzamide (deet) and chiral (1S,2'S)-2-methylpiperidinyl-3-cyclohexene-1-carboxamide (SS220) against the yellowfever mosquito, Aedes aegypti (L.), by using an in vitro assay and human volunteers at 24 nmol compound/cm2 (cloth or skin). Of all compounds tested in an in vitro assay, SS220 ranked as the most effective, whereas catnip oil and the nepetalactone compounds did not differ significantly from each other or from deet. However, in human volunteer bioassays, neither E,Z and Z,E-nepetalactone nor racemic nepetalactone deterred mosquito biting as effectively as SS220 or deet. All compounds differed significantly from the control. We conclude that catnip oil and nepetalactone isomers are significantly less effective than deet or SS220 in deterring the biting of Ae. aegypti.

  1. Irritant and repellent behavioral responses of Aedes aegypti male populations developed for RIDL disease control strategies.

    PubMed

    Kongmee, Montathip; Nimmo, Derric; Labbé, Geneviève; Beech, Camilla; Grieco, John; Alphey, Luke; Achees, Nicole

    2010-11-01

    Behavioral responses of Aedes aegypti male populations developed for Release of Insects Carrying a Dominant Lethal (RIDL) technology and a Malaysian wild-type population of two age groups (4-5 and 8-10 d old) were tested under laboratory conditions against chemical irritants and repellents using the high-throughput screening system device. Results indicate that all male Ae. aegypti test populations showed significant (P < 0.01) behavioral escape responses when exposed to alphacypermethrin, DDT, and deltamethrin at the test dose of 25 nmol/cm2. In addition, all populations showed significant (P < 0.05) spatial repellent responses to DDT, whereas alphacypermethrin and deltamethrin elicited no directional movement in the assay. These data suggest that genetic modification has not suppressed expected irritancy and repellency behavior. Age effects were minimal in both contact irritant and spatial repellent assays. The magnitude of irritant response, based on percentage responding, was stronger in the RIDL test cohorts as compared with the wild-type Malaysian population, but the impact, if any, that this increased behavioral sensitivity might have on the success of a RIDL strategy has yet to be defined. Information of the type reported in the current study is vital in defining the effects of genetic modification on vector behavior and understanding how these behaviors may influence the success of RIDL technology as they relate to other vector control interventions implemented in the same disease-endemic locale.

  2. Combined effect of biopesticides on the digestive enzymatic profiles of Aedes aegypti (Diptera: Culicidae).

    PubMed

    Gamal, Zakia A; Abuldahab, Faten F

    2012-04-01

    This study evaluated efficiency of two bacterial mosquito larvicides and a plant extract one against Aedes aegypti larvae when used in combinations with each other under laboratory conditions, is an integrated method of control. Plant extracts, especially botanical insecticides, are currently studied more and more because of the possibility of their use in plant protection. Many of the natural plant compounds and organic compounds used in the control of insect pests are known to affect digestive enzymes. When fed a diet of rice leaves treated with botanical insecticides and bacterial toxins in bioassays, activities of the digestive enzymes protease, amylase, and lipase in the A. aegypti larvae are affected. Digestive enzyme activities were affected by botanical insecticides and bacterial toxins individually and in combination. When combined, the effect was more severe at low concentration. There were statistically significant differences (P < or = 0.05) in enzyme activities in combined and individual treatments. The combination of Btk and botanical insecticides caused a two-fold decrease in enzyme activity even at reduced concentration. Clear dose-response relationships were established with respect to enzyme activity. A synergistic effect of botanical insecticides and bacterial toxins was found when combined in low doses. These effects are most pronounced in early instars.

  3. Natural vertical transmission of dengue viruses by Aedes aegypti in Bolivia

    PubMed Central

    Le Goff, G.; Revollo, J.; Guerra, M.; Cruz, M.; Barja Simon, Z.; Roca, Y.; Vargas Florès, J.; Hervé, J.P.

    2011-01-01

    The natural transmission of dengue virus from an infected female mosquito to its progeny, namely the vertical transmission, was researched in wild caught Aedes aegypti during an important outbreak in the town of Santa Cruz de la Sierra, Bolivia. Mosquitoes were collected at the preimaginal stages (eggs, larvae and pupae) then reared up to adult stage for viral detection using molecular methods. Dengue virus serotypes 1 and 3 were found to be co-circulating with significant higher prevalence in male than in female mosquitoes. Of the 97 pools of Ae. aegypti (n = 635 male and 748 female specimens) screened, 14 pools, collected in February-May in 2007, were found positive for dengue virus infection: five DEN-1 and nine DEN-3. The average true infection rate (TIR) and minimum infection rate (MIR) were respectively 1.08% and 1.01%. These observations suggest that vertical transmission of dengue virus may be detected in vectors at the peak of an outbreak as well as several months before an epidemic occurs in human population. PMID:21894270

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  6. Characterization of Aedes aegypti (Diptera: Culcidae) production sites in urban Nicaragua.

    PubMed

    Hammond, Samantha N; Gordon, Aubree L; Lugo, Emperatriz del C; Moreno, Gilberto; Kuan, Guillermina M; López, María M; López, Josefa D; Delgado, Marco A; Valle, Sonia I; Espinoza, Perla M; Harris, Eva

    2007-09-01

    To characterize the production patterns of the dengue virus vector Aedes aegypti (L.) (Diptera: Culcidae), pupal surveys were conducted in selected neighborhoods of two major cities in Nicaragua. In León, 833 houses were visited in July and September 2003, corresponding to the beginning and middle of the dengue season; in Managua, 1,365 homes were visited in July 2003. In total, 7,607 containers were characterized, of which 11% were positive for Ae. aegypti larvae and 4% for pupae. In addition to barrels, potted plants and superficial water on tarps and in puddles were identified as highly productive sites. Univariate and multivariate analysis revealed frequency of container use, use of a lid, and rainwater filling as key variables affecting pupal positivity. Importantly, this survey demonstrated the risk associated with the presence of lids, the limited temporal efficacy of temephos, and the lack of association of water availability with risky water storage practices. Finally, we introduce the concept of an efficiency value and an accompanying graphical display system that can facilitate development of targeted pupal control strategies. These data underscore the importance of entomological surveillance of pupal productivity to gather information from which to derive streamlined, efficient, and effective vector control measures to reduce the density of Aedes mosquito larvae and pupae and thus the risk for dengue.

  7. Socioeconomic and Ecological Factors Influencing Aedes aegypti Prevalence, Abundance, and Distribution in Dhaka, Bangladesh

    PubMed Central

    Dhar-Chowdhury, Parnali; Haque, C. Emdad; Lindsay, Robbin; Hossain, Shakhawat

    2016-01-01

    This study examined household risk factors and prevalence, abundance, and distribution of immature Aedes aegypti and Aedes albopictus, and their association with socioeconomic and ecological factors at urban zonal and household levels in the city of Dhaka, Bangladesh. During the 2011 monsoon, 826 households in 12 randomly selected administrative wards were surveyed for vector mosquitoes. Results revealed that the abundance and distribution of immature Ae. aegypti and Ae. albopictus, and pupae-per-person indices did not vary significantly among the zones with varied socioeconomic status. Of 35 different types of identified wet containers, 30 were infested, and among the 23 pupae-positive container types, nine were defined as the “most productive” for pupae including: disposable plastic containers (12.2% of 550), sealable plastic barrels (12.0%), tires (10.4%), abandoned plastic buckets (9.6%), flower tub and trays (8.5%), refrigerator trays (6.5%), plastic bottles (6.4%), clay pots (4.9%), and water tanks (1.6%). When the function of the containers was assessed, ornamental, discarded, and household repairing and reconstruction-related container categories were found significantly associated with the number of pupae in the households. The purpose of storing water and income variables were significant predictors of possession of containers that were infested by vector mosquitoes. PMID:27022149

  8. Synergistic repellent and irritant effect of combined essential oils on Aedes aegypti (L.) mosquitoes.

    PubMed

    Noosidum, Atirach; Chareonviriyaphap, Theeraphap; Chandrapatya, Angsumarn

    2014-12-01

    This study was designed to compare the behavioral responses of Aedes aegypti to a single essential oil and to a mixture of two or three essential oils using an excito-repellency test chamber. Mixtures were prepared from essential oils extracted from Litsea cubeba (LC), Litsea salicifolia (LS), and Melaleuca leucadendron (ML). In general, the mixture of essential oils produced a much stronger escape response by Ae. aegypti, regardless of the test conditions. No significant difference in escape responses was seen when the mixture of oils was compared with a standard commercial product containing DEET. Greater contact irritancy was seen from mixed oils of LC and LS than with other mixed oils. Mixtures of LC and LS at 0.075% showed the highest synergistic action (65.5% escaped) compared to that with unmixed oil alone at the same concentration (LC/20% and LS=32.2%). In addition, mixtures of LC and LS at 0.075% demonstrated the highest non-contact repellency (62.7%) and showed a greater effect than the use of LC (20%) or LS (20.3%) alone. We conclude that mixtures of two essential oils show potential as active ingredients for mosquito repellents.

  9. EFFICIENCY OF DENGUE SEROTYPE 2 VIRUS STRAINS TO INFECT AND DISSEMINATE IN AEDES AEGYPTI

    PubMed Central

    ARMSTRONG, PHILIP M.; RICO-HESSE, REBECA

    2011-01-01

    Dengue serotype 2 (DEN-2) viruses with the potential to cause dengue hemorrhagic fever have been shown to belong to the Southeast (SE) Asian genotype. These viruses appear to be rapidly displacing the American genotype of DEN-2 in the Western Hemisphere. To determine whether distinct genotypes of DEN-2 virus are better adapted to mosquito transmission, we classified 15 viral strains of DEN-2 phylogenetically and compared their ability to infect and disseminate in different populations of Aedes aegypti mosquitoes. Envelope gene nucleotide sequence analysis confirmed that six strains belonged to the American genotype and nine strains were of the SE Asian genotype. The overall rate of disseminated infection in mosquitoes from Texas was 27% for the SE Asian genotype versus 9% for the American genotype. This pattern of infection was similar in another population of mosquitoes sampled from southern Mexico (30% versus 13%). Together, these findings suggest that Ae. aegypti tends to be more susceptible to infection by DEN-2 viruses of the SE Asian genotype than to those of the American genotype, and this may have epidemiologic implications. PMID:12812340

  10. Aedes aegypti from temperate regions of South America are highly competent to transmit dengue virus

    PubMed Central

    2013-01-01

    Background Aedes aegypti is extensively spread throughout South America where it has been responsible for large dengue epidemics during the last decades. Intriguingly, dengue transmission has not been reported in Uruguay and is essentially prevalent in subtropical northern Argentina which borders Uruguay. Methods We assessed vector competence for dengue virus (DENV) of Ae. aegypti populations collected in subtropical Argentina (Corrientes) as well as temperate Uruguay (Salto) and Argentina (Buenos Aires) in 2012 using experimental oral infections with DENV-2. Mosquitoes were incubated at 28°C and examined at 14 and 21 days p.i. to access viral dissemination and transmission. Batches of the Buenos Aires mosquitoes were also incubated at 15°C and 20°C. Results Although mosquitoes from temperate Uruguay and Argentina were competent to transmit DENV, those from subtropical Argentina were more susceptible, displaying the highest virus titters in the head and presenting the highest dissemination of infection and transmission efficiency rates when incubated at 28°C. Interestingly, infectious viral particles could be detected in saliva of mosquitoes from Buenos Aires exposed to 15°C and 20°C. Conclusions There is a potential risk of establishing DENV transmission in Uruguay and for the spread of dengue outbreaks to other parts of subtropical and temperate Argentina, notably during spring and summer periods. PMID:24373423

  11. Impact of elevated CO2 background levels on the host-seeking behaviour of Aedes aegypti.

    PubMed

    Majeed, Shahid; Hill, Sharon Rose; Ignell, Rickard

    2014-02-15

    Mosquitoes rely on carbon dioxide (CO2) to detect and orient towards their blood hosts. However, the variable and rapid fluctuations of atmospheric CO2 concentrations may have an impact on the host-seeking behaviour of mosquitoes. In this study, we analysed the effect of transient elevated background levels of CO2 on the host-seeking behaviour and the physiological characteristics of the CO2-sensitive olfactory receptor neurones (ORNs) in female yellow fever mosquitoes, Aedes aegypti. We show that the take-off and source contact behaviour of A. aegypti is impeded at elevated background levels of CO2 as a result of masking of the stimulus signal. The mechanism underlying this masking during take-off behaviour is one of sensory constraint. We show that the net response of the CO2-ORNs regulates this CO2-related behaviour. Since these neurones themselves are not habituated or fatigued by the transient elevation of background CO2, we propose that habituation of second-order neurones in response to the elevated CO2-ORN activity could be one mechanism by which the net response is transduced by the olfactory system. The findings from this study may help to predict future shifts in mosquito-host interactions and consequently to predict vectorial capacity in the light of climate change.

  12. Bacillus thuringiensis var. israelensis (Bti) Provides Residual Control of Aedes aegypti in Small Containers

    PubMed Central

    Ritchie, Scott A.; Rapley, Luke P.; Benjamin, Seleena

    2010-01-01

    We examined the use of megadoses of VectoBac WG for residual control of Aedes aegypti in 2-L plastic buckets. Doses of 10×, 20×, and 50× the recommended rate of 8 mg/L provided ≥ 90% control for 8, 8, and 23 weeks, respectively. There was no significant difference in mortality between dry (neat) or aqueous mixture of VectoBac WG. Pretreatment of dry containers up to 8 weeks before flooding did not significantly decrease efficacy through 11 success weeks. Thus, megadoses of dry formulations of Bti can be used for residual control of Ae. aegypti in small containers. Furthermore, these doses use small amounts of product (0.08–0.4 g/L) that is more practical to measure than the minute amounts (0.008 g/L) required by the recommended rate, and cost US$2.18 to treat 50 Cairns yards containing an average total of 80 containers. This method could also be used to control Aedes albopictus. PMID:20519600

  13. Dengue Virus Infection of Aedes aegypti Requires a Putative Cysteine Rich Venom Protein.

    PubMed

    Londono-Renteria, Berlin; Troupin, Andrea; Conway, Michael J; Vesely, Diana; Ledizet, Michael; Roundy, Christopher M; Cloherty, Erin; Jameson, Samuel; Vanlandingham, Dana; Higgs, Stephen; Fikrig, Erol; Colpitts, Tonya M

    2015-10-01

    Dengue virus (DENV) is a mosquito-borne flavivirus that causes serious human disease and mortality worldwide. There is no specific antiviral therapy or vaccine for DENV infection. Alterations in gene expression during DENV infection of the mosquito and the impact of these changes on virus infection are important events to investigate in hopes of creating new treatments and vaccines. We previously identified 203 genes that were ≥5-fold differentially upregulated during flavivirus infection of the mosquito. Here, we examined the impact of silencing 100 of the most highly upregulated gene targets on DENV infection in its mosquito vector. We identified 20 genes that reduced DENV infection by at least 60% when silenced. We focused on one gene, a putative cysteine rich venom protein (SeqID AAEL000379; CRVP379), whose silencing significantly reduced DENV infection in Aedes aegypti cells. Here, we examine the requirement for CRVP379 during DENV infection of the mosquito and investigate the mechanisms surrounding this phenomenon. We also show that blocking CRVP379 protein with either RNAi or specific antisera inhibits DENV infection in Aedes aegypti. This work identifies a novel mosquito gene target for controlling DENV infection in mosquitoes that may also be used to develop broad preventative and therapeutic measures for multiple flaviviruses.

  14. Alterations in the Aedes aegypti transcriptome during infection with West Nile, dengue and yellow fever viruses.

    PubMed

    Colpitts, Tonya M; Cox, Jonathan; Vanlandingham, Dana L; Feitosa, Fabiana M; Cheng, Gong; Kurscheid, Sebastian; Wang, Penghua; Krishnan, Manoj N; Higgs, Stephen; Fikrig, Erol

    2011-09-01

    West Nile (WNV), dengue (DENV) and yellow fever (YFV) viruses are (re)emerging, mosquito-borne flaviviruses that cause human disease and mortality worldwide. Alterations in mosquito gene expression common and unique to individual flaviviral infections are poorly understood. Here, we present a microarray analysis of the Aedes aegypti transcriptome over time during infection with DENV, WNV or YFV. We identified 203 mosquito genes that were ≥ 5-fold differentially up-regulated (DUR) and 202 genes that were ≥ 10-fold differentially down-regulated (DDR) during infection with one of the three flaviviruses. Comparative analysis revealed that the expression profile of 20 DUR genes and 15 DDR genes was quite similar between the three flaviviruses on D1 of infection, indicating a potentially conserved transcriptomic signature of flaviviral infection. Bioinformatics analysis revealed changes in expression of genes from diverse cellular processes, including ion binding, transport, metabolic processes and peptidase activity. We also demonstrate that virally-regulated gene expression is tissue-specific. The overexpression of several virally down-regulated genes decreased WNV infection in mosquito cells and Aedes aegypti mosquitoes. Among these, a pupal cuticle protein was shown to bind WNV envelope protein, leading to inhibition of infection in vitro and the prevention of lethal WNV encephalitis in mice. This work provides an extensive list of targets for controlling flaviviral infection in mosquitoes that may also be used to develop broad preventative and therapeutic measures for multiple flaviviruses.

  15. Toxicity and Physiological Actions of Carbonic Anhydrase Inhibitors to Aedes aegypti and Drosophila melanogaster

    PubMed Central

    Francis, Sheena A. M.; Taylor-Wells, Jennina; Gross, Aaron D.; Bloomquist, Jeffrey R.

    2016-01-01

    The physiological role of carbonic anhydrases in pH and ion regulation is crucial to insect survival. We examined the toxic and neurophysiological effects of five carbonic anhydrase inhibitors (CAIs) against Aedes aegypti. The 24 h larvicidal toxicities followed this rank order of potency: dichlorphenamide > methazolamide > acetazolamide = brinzolamide = dorzolamide. Larvicidal activity increased modestly in longer exposures, and affected larvae showed attenuated responses to probing without overt tremors, hyperexcitation, or convulsions. Acetazolamide and dichlorphenamide were toxic to adults when applied topically, but were of low potency and had an incomplete effect (<50% at 300 ng/mosquito) even after injection. Dichlorphenamide was also the most toxic compound when fed to adult mosquitoes, and they displayed loss of posture and occasionally prolonged fluttering of the wings. Co-exposure with 500 ng of the synergist piperonyl butoxide (PBO) increased the toxicity of dichlorphenamide ca. two-fold in feeding assays, indicating that low toxicity was not related to oxidative metabolism. Dichlorphenamide showed mild depolarizing and nerve discharge actions on insect neuromuscular and central nervous systems, respectively. These effects were increased in low buffer salines, indicating they were apparently related to loss of pH control in these tissues. Overall, sulfonamides displayed weak insecticidal properties on Aedes aegypti and are weak lead compounds. PMID:28025488

  16. Biosynthesis of Aedes aegypti lipophorin and gene expression of its apolipoproteins.

    PubMed

    van Heusden, M C; Thompson, F; Dennis, J

    1998-10-01

    The biosynthesis of lipophorin of the yellow fever mosquito, Aedes aegypti, was investigated. Fat bodies were incubated in vitro with radiolabeled methionine and cysteine, and radiolabeled proteins secreted into the medium were analyzed by density gradient ultracentrifugation, SDS-PAGE and fluorography. Lipophorin was synthesized in the fat body and secreted into the medium. Its density was 1.114 g/ml, similar to that of lipophorin circulating in hemolymph. Three peptides of a tryptic digest of apolipophorin II were sequenced and degenerate oligonucleotide primers were designed based on the amino acid sequences. With these primers, a cDNA product of 1.2 kb was amplified by RT-PCR using as template RNA extracted from adult female mosquitoes 24 h after ingestion of a blood meal. This cDNA was cloned, sequenced and used as a probe for Northern blot analysis, which revealed that the apoproteins of lipophorin were coded for by a single mRNA of approximately 10 kb. The expression of the apolipophorins was induced by blood feeding. From the data presented we concluded that Aedes aegypti lipophorin is synthesized in the fat body and that the expression of its apolipophorins is induced by blood feeding.

  17. Natural habitats of Aedes Aegypti in the Caribbean--a review.

    PubMed

    Chadee, D D; Ward, R A; Novak, R J

    1998-03-01

    Natural breeding habitats of Aedes aegypti in the Caribbean region were reviewed by conducting larval surveys in Trinidad. Puerto Rico, and the U.S. Virgin Islands and referring to records from the Mosquitoes of Middle America project. Twelve types of natural habitats were recorded: rock holes (9.7%), calabashes (2.4%), tree holes (19.5%), leaf axils (4.8%), bamboo joints (14.9%), papaya stumps (7.3%), coconut shells (4.8%), bromeliads (7.3%), ground pools (14.9%), coral rock holes (9.7%), crab holes (2.4%), and conch shells (7.3%), of which the coconut shell and calabash habitats were new to the Caribbean. The countries having the highest prevalence of natural habitats were Trinidad. Puerto Rico, and Jamaica, with 9 types (22.0%), 7 types (17.0%), and 6 types (14.6%), respectively. The distribution of natural habitats of Ae. aegypti in the Caribbean region is discussed in relation to vector control measures.

  18. Rhythms and synchronization patterns in gene expression in the Aedes aegypti mosquito

    PubMed Central

    2011-01-01

    Background Aedes aegypti is arguably the most studied of all mosquito species in the laboratory and is the primary vector of both Dengue and Yellow Fever flaviviruses in the field. A large number of transcriptional studies have been made in the species and these usually report transcript quantities observed at a certain age or stage of development. However, circadian oscillation is an important characteristic of gene expression in many animals and plants, modulating both their physiology and behavior. Circadian gene expression in mosquito species has been previously reported but for only a few genes directly involved in the function of the molecular clock. Results Herein we analyze the transcription profiles of 21,494 messenger RNAs using an Ae. aegypti Agilent® microarray. Transcripts were quantified in adult female heads at 24 hours and then again at 72 hours and eight subsequent time points spaced four hours apart. We document circadian rhythms in multiple molecular pathways essential for growth, development, immune response, detoxification/pesticide resistance. Circadian rhythms were also noted in ribosomal protein genes used for normalization in reverse transcribed PCR (RT-PCR) to determine transcript abundance. We report pervasive oscillations and intricate synchronization patterns relevant to all known biological pathways. Conclusion These results argue strongly that transcriptional analyses either need to be made over time periods rather than confining analyses to a single time point or development stage or exceptional care needs to be made to synchronize all mosquitoes to be analyzed and compared among treatment groups. PMID:21414217

  19. Are vectors able to learn about their hosts? A case study with Aedes aegypti mosquitoes.

    PubMed

    Alonso, Wladimir J; Wyatt, Tristram D; Kelly, David W

    2003-07-01

    The way in which vectors distribute themselves amongst their hosts has important epidemiological consequences. While the role played by active host choice is largely unquestioned, current knowledge relates mostly to the innate response of vectors towards stimuli signalling the presence or quality of their hosts. Many of those cues, however, can be unpredictable, and therefore prevent the incorporation of the appropriate response into the vector's behavioural repertoire unless some sort of associative learning is possible. We performed a wide range of laboratory experiments to test the learning abilities of the mosquito, Aedes aegypti. Mosquitoes were exposed to choice procedures in (1) an olfactomenter and (2) a 'visual arena'. Our goal was to determine whether the mosquitoes were able to associate unconditional stimuli (blood feeding, human breath, vibration and electrical shock) with particular odours (citral, carvone, citronella oil and eugenol) and visual patterns (horizontal or vertical black bars) to which they had been previously observed to be responsive. We found no evidence supporting the hypothesis that associative learning abilities are present in adult Ae. aegypti. We discuss the possibilities that the assays employed were either inappropriate or insufficient to detect associative learning, or that associative learning is not possible in this species.

  20. Widespread evidence for interspecific mating between Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in nature.

    PubMed

    Bargielowski, I E; Lounibos, L P; Shin, D; Smartt, C T; Carrasquilla, M C; Henry, A; Navarro, J C; Paupy, C; Dennett, J A

    2015-12-01

    Aedes aegypti and Aedes albopictus, two important vectors of the dengue and chikungunya viruses to humans, often come in contact in their invasive ranges. In these circumstances, a number of factors are thought to influence their population dynamics, including resource competition among the larval stages, prevailing environmental conditions and reproductive interference in the form of satyrization. As the distribution and abundance of Ae. aegypti and Ae. albopictus have profound epidemiological implications, understanding the competitive interactions that influence these patterns in nature is important. While evidence for resource competition and environmental factors had been gathered from the field, the evidence for reproductive interference, though strongly inferred through laboratory trials, remained sparse (one small-scale field trial). In this paper we demonstrate that low rates (1.12-3.73%) of interspecific mating occur in nature among populations of these species that have co-existed sympatrically from 3 to 150yrs. Finally this report contributes a new species-specific primer set for identifying the paternity of sperm extracted from field collected specimens.

  1. Effect of gamma irradiation on the hemocyte-mediated immune response of Aedes aegypti against microfilariae

    SciTech Connect

    Christensen, B.M.; Huff, B.M.; Li, J. )

    1990-07-01

    The effect of gamma irradiation on the melanotic encapsulation response of Aedes aegypti black eye Liverpool strain against inoculated Dirofilaria immitis microfilariae (mff) was assessed at 1, 2, 3, and 6 days postinoculation (PI). Mosquitoes received 6000 rad from a 137Cs source (Shepard Mark I irradiator) at 3 days postemergence and were inoculated with 15-20 mff 24 hr later. These mosquitoes were compared to nonirradiated controls that also were inoculated with 15-20 mff at 3 days postemergence. The immune response was significantly reduced in irradiated mosquitoes as compared with controls at all days PI. Although the response was significantly inhibited compared with controls, irradiated mosquitoes were still capable of eliciting a response against 69% of recovered mff at 6 days PI. External gamma irradiation did not significantly affect the proliferation of hemocytes associated with the melanotic encapsulation response of A. aegypti. The number of circulating hemocytes increased in irradiated mosquitoes in response to inoculated mff in a manner similar to nonirradiated, inoculated controls. Hemocyte monophenol oxidase activity, however, was significantly reduced in gamma-irradiated mosquitoes at 12 hr PI as compared with controls. The reduced immunological capacity of irradiated mosquitoes might be related to an interference with gene activity required for the synthesis or activation of enzymes that are directly or indirectly involved in the biochemical processes associated with the production of melanotic substances that sequester mff.

  2. Dynamics of Midgut Microflora and Dengue Virus Impact on Life History Traits in Aedes aegypti

    PubMed Central

    Hill, Casey L.; Sharma, Avinash; Shouche, Yogesh; Severson, David W.

    2014-01-01

    Significant morbidity and potential mortality following dengue virus infection is a re-emerging global health problem. Due to the limited effectiveness of current disease control methods, mosquito biologists have been searching for new methods of controlling dengue transmission. While much effort has concentrated on determining genetic aspects to vector competence, paratransgenetic approaches could also uncover novel vector control strategies. The interactions of mosquito midgut microflora and pathogens may play significant roles in vector biology. However, little work has been done to see how the microbiome influences the host's fitness and ultimately vector competence. Here we investigated the effects of the midgut microbial environment and dengue infection on several fitness characteristics among three strains of the primary dengue virus vector mosquito Aedes aegypti. This included comparisons of dengue infection rates of females with and without their normal midgut flora. According to our findings, few effects on fitness characteristics were evident following microbial clearance or with dengue virus infection. Adult survivorship significantly varied due to strain and in one strain varied due to antibiotic treatment. Fecundity varied in one strain due to microbial clearance by antibiotics but no variation was observed in fertility due to either treatment. We show here that fitness characteristics of Ae. aegypti vary largely between strains, including varying response to microflora presence or absence, but did not vary in response to dengue virus infection. PMID:25193134

  3. Natural vertical transmission of dengue viruses by Aedes aegypti in Bolivia.

    PubMed

    Le Goff, G; Revollo, J; Guerra, M; Cruz, M; Barja Simon, Z; Roca, Y; Vargas Florès, J; Hervé, J P

    2011-08-01

    The natural transmission of dengue virus from an infected female mosquito to its progeny, namely the vertical transmission, was researched in wild caught Aedes aegypti during an important outbreak in the town of Santa Cruz de la Sierra, Bolivia. Mosquitoes were collected at the preimaginal stages (eggs, larvae and pupae) then reared up to adult stage for viral detection using molecular methods. Dengue virus serotypes 1 and 3 were found to be co-circulating with significant higher prevalence in male than in female mosquitoes. Of the 97 pools of Ae. aegypti (n = 635 male and 748 female specimens) screened, 14 pools, collected in February-May in 2007, were found positive for dengue virus infection: five DEN-1 and nine DEN-3. The average true infection rate (TIR) and minimum infection rate (MIR) were respectively 1.08% and 1.01%. These observations suggest that vertical transmission of dengue virus may be detected in vectors at the peak of an outbreak as well as several months before an epidemic occurs in human population.

  4. The role of male harassment on female fitness for the dengue vector mosquito Aedes aegypti.

    PubMed

    Helinski, Michelle E H; Harrington, Laura C

    2012-08-01

    Sexual harassment studies in insects suggest that females can incur several kinds of costs from male harassment and mating. Here, we examined direct and indirect costs of male harassment on components of female fitness in the predominantly monandrous mosquito Aedes aegypti. To disentangle the costs of harassment versus the costs of mating, we held females at a low or high density with males whose claspers were modified to prevent insemination, and compared these to females held with normal males and to those held with females or alone. A reduced longevity was observed when females were held under high density conditions with males or females, regardless if male claspers had been modified. There was no consistent effect of harassment on female fecundity. Net reproductive rate (R0) was higher in females held at low density with normal males compared to females held with males in the other treatments, even though only a small number of females showed direct evidence of remating. Indirect costs and benefits that were not due to harassment alone were observed. Daughters of females held with normal males at high density had reduced longevity compared to daughters from females held without conspecifics. However, their fitness (R0) was higher compared to females in all other treatments. Overall, our results indicate that A. aegypti females do not suffer a fitness cost from harassment of males when kept at moderate densities, and they suggest the potential for benefits obtained from ejaculate components.

  5. Effects of sublethal concentrations of Vectobac on biological parameters of Aedes aegypti.

    PubMed

    Flores, Adriana E; Garcia, Gustavo Ponce; Badii, Mohammad H; Rodriguez Tovar, M A Luisa; Fernandez Salas, Ildefonso

    2004-12-01

    The effect of sublethal concentrations (30% lethal concentration [LC30] = 0.41 ppm, LC50 = 1.04 ppm, and LC70 = 2.60 ppm) of VectoBac 12 aqueous suspension (AS, Bacillus thuringiensis var. israelensis H-14, 600 ITU/mg) on life parameters of Aedes aegypti and its F1 progeny (not exposed) was assessed in laboratory tests. Based on the data, it was clear that concentrations of 0.41 ppm of VectoBac significantly shortened the duration of the developmental cycle of the exposed mosquitoes, but not that of the F1 (not exposed). Significant differences were found among the proportions of the age-specific survival between each toxic level, whereas the control did not differ from the treated individuals at the LC50 and LC70. The survival curves of the F1 showed significant differences among the different treatments and with the control. A significant effect was found on the fecundity of adults. Age-specific fecundity was markedly lower for the LC50 and LC70 treatments compared to the LC30 treatment and the control. In general, life parameters were affected inversely and significantly at higher concentrations of VectoBac, both in the exposed population of Ae. aegypti and in the F1 (not exposed).

  6. Bionomics of Aedes aegypti subpopulations (Diptera: Culicidae) from Misiones Province, northeastern Argentina.

    PubMed

    Tejerina, Edmundo Fabricio; Almeida, Francisco Felipe Ludueña; Almirón, Walter Ricardo

    2009-01-01

    Life statistics of four Aedes aegypti subpopulations from the subtropical province of Misiones were studied during autumn and winter, under semi-natural conditions, coming from the localities of Posadas (SW), San Javier (SE), Bernardo de Irigoyen (NE) and Puerto Libertad (NW). The eastern subpopulations are geographically separated by the central mountain system of the province from the western subpopulations. High percentages of larval and pupal survival (97-100%) were recorded, and no significant differences were detected among the four subpopulations. Larvae and pupae lasted approximately 8 days to complete their development, no significant differences being detected among the four subpopulations studied. Sex ratio recorded did not differ significantly from 1:1. Male longevity did not show difference among the different subpopulations, but female longevity was remarkably different among the four subpopulations (F=16.27; d.f.=(3;8); P=0.0009), ranging among 11.45 days for San Javier and 57.87 days for Posadas. Fecundity also varied considerably among subpopulations, the greatest number (307.44 eggs/female) being recorded for Posadas (F=4.13; d.f.=(3;8); P=0.04). Ae. aegypti females of the western subpopulations lived longer than the eastern subpopulations studied, therefore, the risk of dengue outbreak would be greater on the Misiones Province border with Paraguay.

  7. Sublethal iridovirus disease of the mosquito Aedes aegypti is due to viral replication not cytotoxicity.

    PubMed

    Marina, C F; Ibarra, J E; Arredondo-Jiménez, J I; Fernández-Salas, I; Valle, J; Williams, T

    2003-06-01

    Invertebrate iridescent viruses (Iridoviridae) possess a highly cytotoxic protein. In mosquitoes (Diptera: Culicidae), invertebrate iridescent virus 6 (IIV-6) usually causes covert (inapparent) infection that reduces fitness. To determine whether sublethal effects of IIV-6 are principally due to cytotoxicity of the viral inoculum (which inhibits macromolecular synthesis in the host), or caused by replication of the virus larvae of the mosquito Aedes aegypti (L) were exposed to untreated IIV-6 virus that had previously been deactivated by heat or ultraviolet light. Control larvae were not exposed to virus. Larval development time was shortest in control larvae and extended in larvae exposed to untreated virus. Covertly infected mosquitoes laid significantly fewer eggs, produced between 20 and 35% fewer progeny and had reduced longevity compared to other treatments. Wing length was shortest in mosquitoes exposed to heat-deactivated virus. Multivariate analysis of the same data identified fecundity and progeny production as the most influential variables in defining differences among treatments. Overall, viral infection resulted in a 34% decrease in the net reproductive rate (R0) of covertly infected mosquitoes, vs. only 5-17% decrease of R0 following treatments with deactivated virus, compared to controls. Sublethal effects of IIV-6 in Ae. aegypti appear to be mainly due to virus replication, rather than cytotoxic effects of the viral inoculum.

  8. River Boats Contribute to the Regional Spread of the Dengue Vector Aedes aegypti in the Peruvian Amazon

    PubMed Central

    Guagliardo, Sarah Anne; Morrison, Amy C.; Barboza, Jose Luis; Requena, Edwin; Astete, Helvio; Vazquez-Prokopec, Gonzalo; Kitron, Uriel

    2015-01-01

    Background and Objectives The dramatic range expansion of the dengue vector Aedes aegypti is associated with various anthropogenic transport activities, but little is known about the underlying mechanisms driving this geographic expansion. We longitudinally characterized infestation of different vehicle types (cars, boats, etc.) to estimate the frequency and intensity of mosquito introductions into novel locations (propagule pressure). Methods Exhaustive adult and immature Ae. aegypti collections were performed on six different vehicle types at five ports and two bus/ taxi departure points in the Amazonian city of Iquitos, Peru during 2013. Aquatic vehicles included 32 large and 33 medium-sized barges, 53 water taxis, and 41 speed boats. Terrestrial vehicles sampled included 40 buses and 30 taxis traveling on the only highway in the region. Ae. aegypti adult infestation rates and immature indices were analyzed by vehicle type, location within vehicles, and sampling date. Results Large barges (71.9% infested) and medium barges (39.4% infested) accounted for most of the infestations. Notably, buses had an overall infestation rate of 12.5%. On large barges, the greatest number of Ae. aegypti adults were found in October, whereas most immatures were found in February followed by October. The vast majority of larvae (85.9%) and pupae (76.7%) collected in large barges were produced in puddles formed in cargo holds. Conclusions Because larges barges provide suitable mosquito habitats (due to dark, damp cargo storage spaces and ample oviposition sites), we conclude that they likely serve as significant contributors to mosquitoes’ propagule pressure across long distances throughout the Peruvian Amazon. This information can help anticipate vector population mixing and future range expansions of dengue and other viruses transmitted by Ae. aegypti. PMID:25860352

  9. Mitochondrial physiology in the major arbovirus vector Aedes aegypti: substrate preferences and sexual differences define respiratory capacity and superoxide production.

    PubMed

    Soares, Juliana B R Correa; Gaviraghi, Alessandro; Oliveira, Marcus F

    2015-01-01

    Adult females of Aedes aegypti are facultative blood sucking insects and vectors of Dengue and yellow fever viruses. Insect dispersal plays a central role in disease transmission and the extremely high energy demand posed by flight is accomplished by a very efficient oxidative phosphorylation process, which take place within flight muscle mitochondria. These organelles play a central role in energy metabolism, interconnecting nutrient oxidation to ATP synthesis, but also represent an important site of cellular superoxide production. Given the importance of mitochondria to cell physiology, and the potential contributions of this organelle for A. aegypti biology and vectorial capacity, here, we conducted a systematic assessment of mitochondrial physiology in flight muscle of young adult A. aegypti fed exclusively with sugar. This was carried out by determining the activities of mitochondrial enzymes, the substrate preferences to sustain respiration, the mitochondrial bioenergetic efficiency and capacity, in both mitochondria-enriched preparations and mechanically permeabilized flight muscle in both sexes. We also determined the substrates preferences to promote mitochondrial superoxide generation and the main sites where it is produced within this organelle. We observed that respiration in A. aegypti mitochondria was essentially driven by complex I and glycerol 3 phosphate dehydrogenase substrates, which promoted distinct mitochondrial bioenergetic capacities, but with preserved efficiencies. Respiration mediated by proline oxidation in female mitochondria was strikingly higher than in males. Mitochondrial superoxide production was essentially mediated through proline and glycerol 3 phosphate oxidation, which took place at sites other than complex I. Finally, differences in mitochondrial superoxide production among sexes were only observed in male oxidizing glycerol 3 phosphate, exhibiting higher rates than in female. Together, these data represent a significant step

  10. siRNA-Mediated Silencing of doublesex during Female Development of the Dengue Vector Mosquito Aedes aegypti

    PubMed Central

    Mysore, Keshava; Sun, Longhua; Tomchaney, Michael; Sullivan, Gwyneth; Adams, Haley; Piscoya, Andres S.; Severson, David W.; Syed, Zainulabeuddin; Duman-Scheel, Molly

    2015-01-01

    The development of sex-specific traits, including the female-specific ability to bite humans and vector disease, is critical for vector mosquito reproduction and pathogen transmission. Doublesex (Dsx), a terminal transcription factor in the sex determination pathway, is known to regulate sex-specific gene expression during development of the dengue fever vector mosquito Aedes aegypti. Here, the effects of developmental siRNA-mediated dsx silencing were assessed in adult females. Targeting of dsx during A. aegypti development resulted in decreased female wing size, a correlate for body size, which is typically larger in females. siRNA-mediated targeting of dsx also resulted in decreased length of the adult female proboscis. Although dsx silencing did not impact female membrane blood feeding or mating behavior in the laboratory, decreased fecundity and fertility correlated with decreased ovary length, ovariole length, and ovariole number in dsx knockdown females. Dsx silencing also resulted in disruption of olfactory system development, as evidenced by reduced length of the female antenna and maxillary palp and the sensilla present on these structures, as well as disrupted odorant receptor expression. Female lifespan, a critical component of the ability of A. aegypti to transmit pathogens, was also significantly reduced in adult females following developmental targeting of dsx. The results of this investigation demonstrate that silencing of dsx during A. aegypti development disrupts multiple sex-specific morphological, physiological, and behavioral traits of adult females, a number of which are directly or indirectly linked to mosquito reproduction and pathogen transmission. Moreover, the olfactory phenotypes observed connect Dsx to development of the olfactory system, suggesting that A. aegypti will be an excellent system in which to further assess the developmental genetics of sex-specific chemosensation. PMID:26544686

  11. Temporal distribution of Aedes aegypti in different districts of Rio de Janeiro, Brazil, measured by two types of traps.

    PubMed

    Honório, N A; Codeço, C T; Alves, F C; Magalhães, M A F M; Lourenço-De-Oliveira, R

    2009-09-01

    Dengue dynamics in Rio de Janeiro, Brazil, as in many dengue-endemic regions of the world, is seasonal, with peaks during the wet-hot months. This temporal pattern is generally attributed to the dynamics of its mosquito vector Aedes aegypti (L.). The objectives of this study were to characterize the temporal pattern of Ae. aegypti population dynamics in three neighborhoods of Rio de Janeiro and its association with local meteorological variables; and to compare positivity and density indices obtained with ovitraps and MosquiTraps. The three neighborhoods are distinct in vegetation coverage, sanitation, water supply, and urbanization. Mosquito sampling was carried out weekly, from September 2006 to March 2008, a period during which large dengue epidemics occurred in the city. Our results show peaks of oviposition in early summer 2007 and late summer 2008, detected by both traps. The ovitrap provided a more sensitive index than MosquiTrap. The MosquiTrap detection threshold showed high variation among areas, corresponding to a mean egg density of approximately 25-52 eggs per ovitrap. Both temperature and rainfall were significantly related to Ae. aegypti indices at a short (1 wk) time lag. Our results suggest that mean weekly temperature above 22-24 degrees C is strongly associated with high Ae. aegypti abundance and consequently with an increased risk of dengue transmission. Understanding the effects of meteorological variables on Ae. aegypti population dynamics will help to target control measures at the times when vector populations are greatest, contributing to the development of climate-based control and surveillance measures for dengue fever in a hyperendemic area.

  12. Investigating the Potential Range Expansion of the Vector Mosquito Aedes aegypti in Mexico with NASA Earth Science Remote Sensing Results

    NASA Astrophysics Data System (ADS)

    Crosson, W. L.; Eisen, L.; Estes, M. G.; Estes, S. M.; Hayden, M.; Lozano-Fuentes, S.; Monaghan, A. J.; Moreno Madriñán, M. J.; Ochoa, C.; Quattrochi, D.; Tapia, B.; Welsh-Rodriguez, C. M.

    2012-12-01

    In tropical and sub-tropical regions, the mosquito Aedes aegypti is the major vector for the virus causing dengue, a serious public health issue in these areas. Through ongoing NSF- and NASA-funded studies, field surveys of Aedes aegypti and an integrated modeling approach are being used to improve our understanding of the potential range of the mosquito to expand toward heavily populated high elevation areas such as Mexico City under various climate change and socio-economic scenarios. This work serves three primary objectives: (1) Employ NASA remotely-sensed data to supplement the environmental monitoring and modeling component of the project. These data -- for example, surface temperature, precipitation, vegetation indices, soil moisture and elevation -- are critical for understanding the habitat necessary for mosquito survival and abundance; (2) Implement training sessions to instruct scientists and students from Mexico and the U.S. on how to use remote sensing and implement the NASA SERVIR Regional Visualization and Monitoring System; (3) Employ the SERVIR framework to optimize the dissemination of key project results in order to increase their societal relevance and benefits in developing climate adaptation strategies. Field surveys of larval, pupal and adult Aedes aegypti, as well as detailed physical and social household characteristics, were conducted in the summers of 2011and 2012 at geographic scales from the household to the community along a transect from sea level to 2400 m ASL. These data are being used in models to estimate Aedes aegypti habitat suitability. In 2011, Aedes aegypti were identified at an elevation of over 2150 m in Puebla, the highest elevation at which this species has been observed.

  13. Impact of Autocidal Gravid Ovitraps on Chikungunya Virus Incidence in Aedes aegypti (Diptera: Culicidae) in Areas With and Without Traps.

    PubMed

    Barrera, Roberto; Acevedo, Veronica; Felix, Gilberto E; Hemme, Ryan R; Vazquez, Jesus; Munoz, Jorge L; Amador, Manuel

    2016-12-28

    Puerto Rico detected the first confirmed case of chikungunya virus (CHIKV) in May 2014 and the virus rapidly spread throughout the island. The invasion of CHIKV allowed us to observe Aedes aegypti (L.) densities, infection rates, and impact of vector control in urban areas using CDC autocidal gravid ovitraps (AGO traps) for mosquito control over several years. Because local mosquitoes can only get the virus from infectious residents, detecting the presence of virus in mosquitoes functions as a proxy for the presence of virus in people. We monitored the incidence of CHIKV in gravid females of Ae. aegypti in four neighborhoods-two with three AGO traps per home in most homes and two nearby neighborhoods without AGO mosquito control traps. Monitoring of mosquito density took place weekly using sentinel AGO traps from June to December 2014. In all, 1,334 pools of female Ae. aegypti (23,329 individuals) were processed by real-time reverse transcription PCR to identify CHIKV and DENV RNA. Density of Ae. aegypti females was 10.5 times lower (91%) in the two areas with AGO control traps during the study. Ten times (90.9%) more CHIKV-positive pools were identified in the nonintervention areas (50/55 pools) than in intervention areas (5/55). We found a significant linear relationship between the number of positive pools and both density of Ae. aegypti and vector index (average number of expected infected mosquitoes per trap per week). Temporal and spatial patterns of positive CHIKV pools suggested limited virus circulation in areas with AGO traps.

  14. Salinity alters snakeskin and mesh transcript abundance and permeability in midgut and Malpighian tubules of larval mosquito, Aedes aegypti.

    PubMed

    Jonusaite, Sima; Donini, Andrew; Kelly, Scott P

    2017-03-01

    This study examined the distribution and localization of the septate junction (SJ) proteins snakeskin (Ssk) and mesh in osmoregulatory organs of larval mosquito (Aedes aegypti), as well as their response to altered environmental salt levels. Ssk and mesh transcripts and immunoreactivity were detected in tissues of endodermal origin such as the midgut and Malpighian tubules of A. aegypti larvae, but not in ectodermally derived hindgut and anal papillae. Immunolocalization of Ssk and mesh in the midgut and Malpighian tubules indicated that both proteins are concentrated at regions of cell-cell contact between epithelial cells. Transcript abundance of ssk and mesh was higher in the midgut and Malpighian tubules of brackish water (BW, 30% SW) reared A. aegypti larvae when compared with freshwater (FW) reared animals. Therefore, [(3)H]polyethylene glycol (MW 400Da, PEG-400) flux was examined across isolated midgut and Malpighian tubule preparations as a measure of their paracellular permeability. It was found that PEG-400 flux was greater across the midgut of BW versus FW larvae while the Malpighian tubules of BW-reared larvae had reduced PEG-400 permeability in conjunction with increased Cl(-) secretion compared to FW animals. Taken together, data suggest that Ssk and mesh are found in smooth SJs (sSJs) of larval A. aegypti and that their abundance alters in association with changes in epithelial permeability when larvae reside in water of differing salt content. This latter observation suggests that Ssk and mesh play a role in the homeostatic control of salt and water balance in larval A. aegypti.

  15. Mitochondrial Physiology in the Major Arbovirus Vector Aedes aegypti: Substrate Preferences and Sexual Differences Define Respiratory Capacity and Superoxide Production

    PubMed Central

    Soares, Juliana B. R. Correa; Gaviraghi, Alessandro; Oliveira, Marcus F.

    2015-01-01

    Adult females of Aedes aegypti are facultative blood sucking insects and vectors of Dengue and yellow fever viruses. Insect dispersal plays a central role in disease transmission and the extremely high energy demand posed by flight is accomplished by a very efficient oxidative phosphorylation process, which take place within flight muscle mitochondria. These organelles play a central role in energy metabolism, interconnecting nutrient oxidation to ATP synthesis, but also represent an important site of cellular superoxide production. Given the importance of mitochondria to cell physiology, and the potential contributions of this organelle for A. aegypti biology and vectorial capacity, here, we conducted a systematic assessment of mitochondrial physiology in flight muscle of young adult A. aegypti fed exclusively with sugar. This was carried out by determining the activities of mitochondrial enzymes, the substrate preferences to sustain respiration, the mitochondrial bioenergetic efficiency and capacity, in both mitochondria-enriched preparations and mechanically permeabilized flight muscle in both sexes. We also determined the substrates preferences to promote mitochondrial superoxide generation and the main sites where it is produced within this organelle. We observed that respiration in A. aegypti mitochondria was essentially driven by complex I and glycerol 3 phosphate dehydrogenase substrates, which promoted distinct mitochondrial bioenergetic capacities, but with preserved efficiencies. Respiration mediated by proline oxidation in female mitochondria was strikingly higher than in males. Mitochondrial superoxide production was essentially mediated through proline and glycerol 3 phosphate oxidation, which took place at sites other than complex I. Finally, differences in mitochondrial superoxide production among sexes were only observed in male oxidizing glycerol 3 phosphate, exhibiting higher rates than in female. Together, these data represent a significant step

  16. Investigating the Potential Range Expansion of the Vector Mosquito Aedes Aegypti in Mexico with NASA Earth Science Remote Sensing Results

    NASA Technical Reports Server (NTRS)

    Crosson, W. L.; Estes, M. G.; Estes, S. M.; Hayden, M.; Monaghan, A. J.; Eisen, L.; Lozano-Fuentes, S.; Ochoa, C.; Tapia, B.; Welsh-Rodriquez, C. M.; Quattrochi, D.; MorenoMadrinan, M. J.

    2012-01-01

    In tropical and sub ]tropical regions, the mosquito Aedes aegypti is the major vector for the virus causing dengue, a serious public health issue in these areas. Through ongoing NSF- and NASA-funded studies, field surveys of Aedes aegypti and an integrated modeling approach are being used to improve our understanding of the potential range of the mosquito to expand toward heavily populated high elevation areas such as Mexico City under various climate change and socio ]economic scenarios. This work serves three primary objectives: (1) Employ NASA remotely-sensed data to supplement the environmental monitoring and modeling component of the project. These data-- for example, surface temperature, precipitation, vegetation indices, soil moisture and elevation-- are critical for understanding the habitat necessary for mosquito survival and abundance; (2) Implement training sessions to instruct scientists and students from Mexico and the U.S. on how to use remote sensing and implement the NASA SERVIR Regional Visualization and Monitoring System; (3) Employ the SERVIR framework to optimize the dissemination of key project results in order to increase their societal relevance and benefits in developing climate adaptation strategies. Field surveys of larval, pupal and adult Aedes aegypti, as well as detailed physical and social household characteristics, were conducted in the summers of 2011and 2012 at geographic scales from the household to the community along a transect from sea level to 2400 m ASL. These data are being used in models to estimate Aedes aegypti habitat suitability. In 2011, Aedes aegypti were identified at an elevation of over 2150 m in Puebla, the highest elevation at which this species has been observed.

  17. Residual effects of TMOF-Bti formulations against 1st instar Aedes aegypti Linnaeus larvae outside laboratory

    PubMed Central

    Saiful, AN; Lau, MS; Sulaiman, S; Hidayatulfathi, O

    2012-01-01

    Objective To evaluate the effectiveness and residual effects of trypsin modulating oostatic factor-Bacillus thuringiensis israeliensis (TMOF-Bti) formulations against Aedes aegypti (Ae. aegypti) (L.) larvae at UKM Campus Kuala Lumpur. Methods Twenty first instar Ae. aegypti larvae were added in each bucket containing 4 L of water supplied with crushed dried leaf powder as their source of food. Combination of TMOF-Bti in rice husk formulation with the following weights viz 10, 25, 50 and 100 mg, respectively in duplicate was distributed in the buckets; while TMOF-Bti in wettable powder formulation each weighing viz 2, 5, 10 and 20 mg, respectively in duplicate was also placed in the buckets. The control buckets run in duplicate with 4 L of water and 20 first instar Ae. aegypti larvae. All buckets were covered with mosquito netting. Larval mortality was recorded after 24 hours and weekly for five weeks. A new batch of 20 1st instar larvae Ae. aegypti was introduced into each bucket weekly without additional TMOF-Bti rice husk formulation or wettable powder. The experiment was repeated for four times. Results The result of the study showed that all formulations were very effective on the first two weeks by giving 100% larval mortality for all concentrations applied. The TMOF (2%) + Bti (2%) had a good residual effect until the end of 3rd week, TMOF (4%) + Bti (4%) until 4th week, wettable powder TMOF (20%) + Bti (20%) until the third week. Conclusions From the results it can be concluded that the TMOF-Bti formulations can be utilized in dengue vector control. PMID:23569922

  18. siRNA-Mediated Silencing of doublesex during Female Development of the Dengue Vector Mosquito Aedes aegypti.

    PubMed

    Mysore, Keshava; Sun, Longhua; Tomchaney, Michael; Sullivan, Gwyneth; Adams, Haley; Piscoya, Andres S; Severson, David W; Syed, Zainulabeuddin; Duman-Scheel, Molly

    2015-11-01

    The development of sex-specific traits, including the female-specific ability to bite humans and vector disease, is critical for vector mosquito reproduction and pathogen transmission. Doublesex (Dsx), a terminal transcription factor in the sex determination pathway, is known to regulate sex-specific gene expression during development of the dengue fever vector mosquito Aedes aegypti. Here, the effects of developmental siRNA-mediated dsx silencing were assessed in adult females. Targeting of dsx during A. aegypti development resulted in decreased female wing size, a correlate for body size, which is typically larger in females. siRNA-mediated targeting of dsx also resulted in decreased length of the adult female proboscis. Although dsx silencing did not impact female membrane blood feeding or mating behavior in the laboratory, decreased fecundity and fertility correlated with decreased ovary length, ovariole length, and ovariole number in dsx knockdown females. Dsx silencing also resulted in disruption of olfactory system development, as evidenced by reduced length of the female antenna and maxillary palp and the sensilla present on these structures, as well as disrupted odorant receptor expression. Female lifespan, a critical component of the ability of A. aegypti to transmit pathogens, was also significantly reduced in adult females following developmental targeting of dsx. The results of this investigation demonstrate that silencing of dsx during A. aegypti development disrupts multiple sex-specific morphological, physiological, and behavioral traits of adult females, a number of which are directly or indirectly linked to mosquito reproduction and pathogen transmission. Moreover, the olfactory phenotypes observed connect Dsx to development of the olfactory system, suggesting that A. aegypti will be an excellent system in which to further assess the developmental genetics of sex-specific chemosensation.

  19. Larvicidal activity of silver nanoparticles synthesized using Plumeria rubra plant latex against Aedes aegypti and Anopheles stephensi.

    PubMed

    Patil, Chandrashekhar D; Patil, Satish V; Borase, Hemant P; Salunke, Bipinchandra K; Salunkhe, Rahul B

    2012-05-01

    In the present study activity of silver nanoparticles (AgNPs) synthesized using Plumeria rubra plant latex against second and fourth larval instar of Aedes aegypti and Anopheles stephensi was determined. Range of concentrations of synthesized AgNps (10, 5, 2.5, 1.25, 0.625, 0.3125 ppm) and aqueous crude latex (1,000, 500, 250, 125, 62.50, 31.25 ppm) were tested against larvae of A. aegypti and A. Stephensi. The synthesized AgNps from P. rubra latex were highly toxic than crude latex extract in both mosquito species. The LC(50) values for second and fourth larval instars after 24 h of crude latex exposure were 1.49, 1.82 ppm against A. aegypti and 1.10, 1.74 ppm against A. stephensi respectively. These figures were 181.67, 287.49 ppm against A. aegypti and 143.69, 170.58 ppm against A. stephensi respectively for crude latex extract. The mortality rates were positively correlated with the concentration of AgNPs. The characterization studies of synthesized AgNPs by UV-Vis spectrophotometry, transmission electron microscopy (TEM), Particle size analysis (PSA) and zeta potential confirmed the spherical shape and size (32-200 nm) of silver nanoparticles along with stability. Toxicity studies carried out against non-target fish species Poecilia reticulata, the most common organism in the habitats of A. aegypti and A. stephensi showed no toxicity at LC(50) and LC(90) doses of the AgNPs. This is the first report on mosquito larvicidal activity of latex synthesized nanoparticles.

  20. Mosquito larvicidal activity of Aloe vera (Family: Liliaceae) leaf extract and Bacillus sphaericus, against Chikungunya vector, Aedes aegypti

    PubMed Central

    Subramaniam, Jayapal; Kovendan, Kalimuthu; Mahesh Kumar, Palanisamy; Murugan, Kadarkarai; Walton, William

    2012-01-01

    The bio-efficacy of Aloe vera leaf extract and bacterial insecticide, Bacillus sphaericus larvicidal activity was assessed against the first to fourth instars larvae of Aedes aegypti, under the laboratory conditions. The plant material was shade dried at room temperature and powdered coarsely. A. vera and B. sphaericus show varied degrees of larvicidal activity against various instars larvae of A. aegypti. The LC50 of A. vera against the first to fourth instars larvae were 162.74, 201.43, 253.30 and 300.05 ppm and the LC90 442.98, 518.86, 563.18 and 612.96 ppm, respectively. B. sphaericus against the first to fourth instars larvae the LC50 values were 68.21, 79.13, 93.48, and 107.05 ppm and the LC90 values 149.15, 164.67, 183.84, and 201.09 ppm, respectively. However, the combined treatment of A. vera + B. sphaericus (1:2) material shows highest larvicidal activity of the LC50 values 54.80, 63.11, 74.66 and 95.10 ppm; The LC90 values of 145.29, 160.14, 179.74 and 209.98 ppm, against A. aegypti in all the tested concentrations than the individuals and clearly established that there is a substantial amount of synergist act. The present investigation clearly exhibits that both A. vera and B. sphaericus materials could serve as a potential larvicidal agent. Since, A. aegypti is a container breeder vector mosquito this user and eco-friendly and low-cost vector control strategy could be a viable solution to the existing dengue disease burden. Therefore, this study provides first report on the mosquito larvicidal activity the combined effect of A. vera leaf extract and B. sphaericus against as target species of A. aegypti. PMID:23961212

  1. Abundance and prevalence of Aedes aegypti immatures and relationships with household water storage in rural areas in southern Viet Nam.

    PubMed

    Nguyen, Le Anh P; Clements, Archie C A; Jeffery, Jason A L; Yen, Nguyen Thi; Nam, Vu Sinh; Vaughan, Gregory; Shinkfield, Ramon; Kutcher, Simon C; Gatton, Michelle L; Kay, Brian H; Ryan, Peter A

    2011-06-01

    Since 2000, the Government of Viet Nam has committed to provide rural communities with increased access to safe water through a variety of household water supply schemes (wells, ferrocement tanks and jars) and piped water schemes. One possible, unintended consequence of these schemes is the concomitant increase in water containers that may serve as habitats for dengue mosquito immatures, principally Aedes aegypti. To assess these possible impacts we undertook detailed household surveys of Ae. aegypti immatures, water storage containers and various socioeconomic factors in three rural communes in southern Viet Nam. Positive relationships between the numbers of household water storage containers and the prevalence and abundance of Ae. aegypti immatures were found. Overall, water storage containers accounted for 92-97% and 93-96% of the standing crops of III/IV instars and pupae, respectively. Interestingly, households with higher socioeconomic levels had significantly higher numbers of water storage containers and therefore greater risk of Ae. aegypti infestation. Even after provision of piped water to houses, householders continued to store water in containers and there was no observed decrease in water storage container abundance in these houses, compared to those that relied entirely on stored water. These findings highlight the householders' concerns about the limited availability of water and their strong behavoural patterns associated with storage of water. We conclude that household water storage container availability is a major risk factor for infestation with Ae. aegypti immatures, and that recent investment in rural water supply infrastructure are unlikely to mitigate this risk, at least in the short term.

  2. The influence of diet on the use of near-infrared spectroscopy to determine the age of female Aedes aegypti mosquitoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Interventions targeting adult mosquitoes are used to combat transmission of vector-borne diseases, including dengue. Without available vaccines, targeting the primary vector, Aedes aegypti, is essential to prevent transmission. Older mosquitoes (>/='7 days) are of greatest epidemiological significan...

  3. Use of genetic polymorphisms detected by the random-amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) for differentiation and identification of Aedes aegypti subspecies and populations.

    PubMed

    Ballinger-Crabtree, M E; Black, W C; Miller, B R

    1992-12-01

    Amplification of random regions of genomic DNA using 10-base primers in the random-amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) was used to differentiate and identify mosquito populations based on genetic variation. Genomic DNA was extracted from individual mosquitoes from 11 geographic populations of Aedes aegypti and amplified in PCR reactions using single primers of arbitrary nucleotide sequence. Discriminant analysis of the population frequencies of RAPD fragments produced using three different primers allowed accurate discrimination between the geographic populations in 89% of individuals and between subspecies (Ae. aegypti aegypti versus Ae. aegypti formosus) in 100% of mosquitoes tested. The genetic relatedness of the populations was estimated using three different statistical methods, and unknown populations were correctly classified in a blind test. These results indicate that the RAPD-PCR technique will be useful in studies of arthropod molecular taxonomy and in epidemiologic studies of the relatedness of geographic populations and vector movement.

  4. Comparative Susceptibility of Aedes albopictus and Aedes aegypti to Dengue Virus Infection After Feeding on Blood of Viremic Humans: Implications for Public Health.

    PubMed

    Whitehorn, James; Kien, Duong Thi Hue; Nguyen, Nguyet Minh; Nguyen, Hoa L; Kyrylos, Peter P; Carrington, Lauren B; Tran, Chau Nguyen Bich; Quyen, Nguyen Thanh Ha; Thi, Long Vo; Le Thi, Dui; Truong, Nguyen Thanh; Luong, Tai Th