Evaluation of Mesocyclops annulatus (Copepoda: Cyclopoidea) as a control agent of Aedes aegypti (Diptera: Culicidae) in Argentina.

We evaluated the potential of Mesocyclops annulatus as a control agent of Aedes aegypti in La Plata city (Argentina). Mosquito larval survivorship due to predation by these copepods was estimated at weekly intervals during the oviposition period of A. aegypti. Mean weekly A. aegypti larval survivorship in cylindrical plastic containers (12 cm height and 11 cm diameter) with copepods was significantly lower than in control containers. Furthermore, weekly larval survival was negatively correlated with M. annulatus adult density, and approximately 23 adult copepods/container would be a threshold density over which the weekly mosquito larval survivorship approached zero. The copepods were able to persist in all containers during approximately 100 days (in three of them until the end of the experiment: 155 days) without the resource represented by A. aegypti larvae. The predation and persistence observed suggest that M. annulatus is a potential control agent to be considered in biological control programs.Fil: Marti, Gerardo Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Micieli, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Scorsetti, Ana Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Liljesthrom, Gerardo Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentin

Presence of ascogregarina culicis and ascogregarina sp. In natural sympatric populations of aedes aegypti and ae. albopictus (diptera: Culicidae) in argentina

Aedes aegypti is the main vector of the four arboviruses in America which have the greatest impact on human health. The introduction of Aedes albopictus in South America and Argentina acquires importance given the possibility that this species may be a new vector of arboviruses in this region. For this reason, the studies of the biology of their parasites, such as Ascogregarina spp., should be important for the knowledge of the invasive behavior of these vectors. We reported the finding of Ascogregarina culicis in Aedes aegypti and Ascogregarina sp. in Ae. albopictus populations in subtropical Argentina. The prevalence of parasitism by A. culicis in Ae. aegypti and Ascogregrarina sp. in Ae. albopictus was 34.81% (n = 464) and 37.23% (n = 70), respectively, differing between the seasons and habitats. The infection intensity caused by A. culicis and Ascogregarina sp. varied between 1 to 250 and 1 to 327 trophozoites respectively. Ascogregarina culicis was found throughout the all sampling period of Ae. aegypti (June 2016-April 2018). However the presence of Ascogregarina sp. in the midgut of Ae. albopictus was not recorded throughout the whole sampling period despite the presence of the host.Fil: Alonso, Ana Carolina. Universidad Nacional del Nordeste. Instituto de Medicina Regional. Área de Entomología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Stein, Marina. Universidad Nacional del Nordeste. Instituto de Medicina Regional. Área de Entomología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Micieli, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentin

Determinación del período estacional de oviposición de Aedes aegypti (Diptera: Culicidae) en la ciudad de Santa Rosa, La Pampa, Argentina

Se estudió el período de oviposición de Aedes aegypti L. para Santa Rosa, La Pampa, Argentina. Se ubicaron ovitrampas, durante el año 2011, en cinco ubicaciones diferentes de la ciudad. Se las revisó semanalmente durante todo ese año. También se estudió la relación entre temperatura y actividad de oviposición semanal, observándose un cese en la actividad de oviposición cuando la temperatura media descendió por debajo de los 16°C. Estos datos permiten ampliar el conocimiento de este vector en la capital de la provincia, información necesaria para la implementación de medidas de control en dicha ciudad.The oviposition period of Aedes aegypti L. was studied for Santa Rosa, La Pampa, Argentina. Ovitraps were placed during the year 2011 in five different locations of this city and weekly samplings were carried out during that year. The relationship between temperature and weekly oviposition activity was also studied and a stop in the oviposition activity was observed when the temperature dropped below 16°C. These data allow us to extend the knowledge of this vector in the provincial capital, providing as well the necessary information to implement control measures in this city.Fil: Breser, Victor Julián. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentina;Fil: Diez, Fernando. Universidad Nacional de la Pampa. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Naturales. Pabellon de Biología; Argentina;Fil: Rossi, Gustavo Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Estudios Parasitológicos y de Vectores (i); Argentina;Fil: Micieli, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Estudios Parasitológicos y de Vectores (i); Argentina

Use of the neotropical fish Cnesterodon decemmaculatus for long-term control of Culex pipiens L. in Argentina

We released the native mosquito fish, Cnesterodon decemmaculatus, into suburban 37 drainage ditches to evaluate its potential as a long-acting agent for the control of CulexCnesterodon decemmaculatus, into suburban 37 drainage ditches to evaluate its potential as a long-acting agent for the control of CulexCulex 38 pipiens larvae in natural breeding sites. The inoculation of predatory fish was conducted in 9 ditches at three densities: 1, 7, and 13 fish/m2 39 during a 2-year period (2006—2008). 40 The number of immature stages of Cx. pipiens was recorded before and after release. On 41 a monthly basis, the digestive-tract contents of some fish and the average number of 42 offspring from the females was recorded. Fifteen weeks after release, a 99% reduction 43 in the number of immature mosquito stages was recorded in the drainage ditches containing 13 fish/m244 , while at 22 weeks, a 99% reduction was also observed in those with 7 fish/m2. The ditches with 1 fish/m2 45 had lower densities of immature mosquito 46 stages relative to the controls, but over the entire experiment these observations did not 47 prove statistically significant. The number of offspring per adult C. decemmaculatuspipiens larvae in natural breeding sites. The inoculation of predatory fish was conducted in 9 ditches at three densities: 1, 7, and 13 fish/m2 39 during a 2-year period (2006—2008). 40 The number of immature stages of Cx. pipiens was recorded before and after release. On 41 a monthly basis, the digestive-tract contents of some fish and the average number of 42 offspring from the females was recorded. Fifteen weeks after release, a 99% reduction 43 in the number of immature mosquito stages was recorded in the drainage ditches containing 13 fish/m244 , while at 22 weeks, a 99% reduction was also observed in those with 7 fish/m2. The ditches with 1 fish/m2 45 had lower densities of immature mosquito 46 stages relative to the controls, but over the entire experiment these observations did not 47 prove statistically significant. The number of offspring per adult C. decemmaculatus2 39 during a 2-year period (2006—2008). 40 The number of immature stages of Cx. pipiens was recorded before and after release. On 41 a monthly basis, the digestive-tract contents of some fish and the average number of 42 offspring from the females was recorded. Fifteen weeks after release, a 99% reduction 43 in the number of immature mosquito stages was recorded in the drainage ditches containing 13 fish/m244 , while at 22 weeks, a 99% reduction was also observed in those with 7 fish/m2. The ditches with 1 fish/m2 45 had lower densities of immature mosquito 46 stages relative to the controls, but over the entire experiment these observations did not 47 prove statistically significant. The number of offspring per adult C. decemmaculatusCx. pipiens was recorded before and after release. On 41 a monthly basis, the digestive-tract contents of some fish and the average number of 42 offspring from the females was recorded. Fifteen weeks after release, a 99% reduction 43 in the number of immature mosquito stages was recorded in the drainage ditches containing 13 fish/m244 , while at 22 weeks, a 99% reduction was also observed in those with 7 fish/m2. The ditches with 1 fish/m2 45 had lower densities of immature mosquito 46 stages relative to the controls, but over the entire experiment these observations did not 47 prove statistically significant. The number of offspring per adult C. decemmaculatus244 , while at 22 weeks, a 99% reduction was also observed in those with 7 fish/m2. The ditches with 1 fish/m2 45 had lower densities of immature mosquito 46 stages relative to the controls, but over the entire experiment these observations did not 47 prove statistically significant. The number of offspring per adult C. decemmaculatus2. The ditches with 1 fish/m2 45 had lower densities of immature mosquito 46 stages relative to the controls, but over the entire experiment these observations did not 47 prove statistically significant. The number of offspring per adult C. decemmaculatusC. decemmaculatus 48 female ranged from 4 ± 1.4 (mean ± SD) to 7.4 ± 0.9. Larval remains were detect.Fil: Tranchida, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Pelizza, Sebastian Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Bisaro, V.. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; ArgentinaFil: Beltrán, C.. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; ArgentinaFil: Garcia, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Micieli, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentin

First report on knockdown resistance mutations in wild populations of Aedes aegypti from Argentina determined by a novel multiplex high-resolution melting polymerase chain reaction method

Background: The mosquito Aedes aegypti is an urban vector of dengue and other arboviruses. During epidemics of these viruses, pyrethroid insecticides are used for the control of adult mosquitoes. The worldwide resistance of Ae. aegypti to these insecticides is a cause of failure of vector control campaigns. The primary target of pyrethroids is the voltage-gated sodium channel. Point mutations in the gene coding for this channel, called knockdown resistance (kdr) mutations, are associated with pyrethroid resistance. Two kdr mutations, V1016I and F1534C, have increased in frequency in natural populations of Ae. aegypti in the Americas during the last decade. Their association with pyrethroid resistance has been largely demonstrated in field populations throughout the Americas, and in in vitro assays. Diagnostics for kdr polymorphism allow early detection of the spread of insecticide resistance, which is critical for timely decisions on vector management. Given the importance of resistance management, high-throughput methods for kdr genotyping are valuable tools as they can be used for resistance monitoring programs. These methods should be cost-effective, to allow regional-scale surveys. Despite the extensive presence of Ae. aegypti and incidence of dengue in Argentina, the presence, abundance, and distribution of kdr mutations in populations of this mosquito have yet to be reported for the country. Methods: Aedes aegypti samples were collected as immature stages or adults from Buenos Aires Metropolitan Area and northern localities of Tartagal (Salta Province) and Calilegua (Jujuy Province). Immature stages were maintained in the laboratory until they developed into adults. A high-resolution melting assay, based on an analysis of melting temperatures, was developed for the simultaneous genotyping of V1016I and F1534C kdr mutations. We used this method to infer the presence and frequencies of kdr alleles in 11 wild populations from Argentina. Results: We demonstrated the presence of kdr mutations in Ae. aegypti in Argentina in regions where this species is under different selection pressures due to the use of pyrethroids. The populations under analysis are located in geographically distant regions of the species’ distribution in Argentina: the northern provinces of Salta and Jujuy and the Buenos Aires Metropolitan Area. Higher frequencies of resistant-associated alleles were detected in the northern region. We report a multiplex high-throughput assay based on a high-resolution melting polymerase chain reaction method for the simultaneous genotyping of V1016I and F1534C kdr mutations. This assay was shown to be cost-effective, and thus provides an interesting molecular tool for kdr genotyping in A. aegypti control campaigns. Conclusions: We report, to the best of our knowledge for the first time, the presence of kdr mutations in populations of Ae. aegypti from geographically distant locations of Argentina that differ with respect to their epidemiological situation and history of mosquito control. We have developed a high-throughput method for the genotyping of kdr mutations in Ae. aegypti from the Americas. Given its affordability and short running time, this method can be used in control campaigns to monitor the presence and spread of kdr alleles. The information provided here is relevant for the rational design of control strategies in the context of integrated vector management.Fil: Barrera Illanes, Alberto Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Endocrinología Experimental y Aplicada. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Endocrinología Experimental y Aplicada; ArgentinaFil: Micieli, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Ibáñez, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Santini, Maria Soledad. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Martins, Ademir J.. Fundación Oswaldo Cruz; BrasilFil: Ons, Sheila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Endocrinología Experimental y Aplicada. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Endocrinología Experimental y Aplicada; Argentin

Differential Effects of Temperature and Mosquito Genetics Determine Transmissibility of Arboviruses by Aedes aegypti in Argentina

Aedes aegypti (L.) (Diptera: Culicidae) have a global distribution and are the primary vector of a number of mosquito-borne viruses responsible for epidemics throughout the Americas. As in much of South America, the threat from pathogens including dengue virus (DENV; Flaviviridae, Flavivirus) and chikungunya virus (CHIKV; Togaviridae, Alphavirus) has increased in Argentina in recent years. The complexity of transmission cycles makes predicting the occurrence and intensity of arbovirus outbreaks difficult. To gain a better understanding of the risk of DENV and CHIKV in Argentina and the factors influencing this risk, we evaluated the role of population and temperature in the vector competence and vectorial capacity (VC) of Ae. aegypti from geographically and ecologically distinct locations. Our results demonstrate that intrinsic and extrinsic factors including mosquito population, viral species, and temperature significantly influence both vector competence and overall VC of Ae. aegypti in Argentina, yet also that the magnitude of these influences is highly variable. Specifically, results suggest that CHIKV competence is more dependent on mosquito genetics than is DENV competence, whereas temperature has a greater effect on DENV transmission. In addition, although there is an overall positive correlation between temperature and competence for both viruses, there are exceptions to this for individual virus?population combinations. Together, these data establish large variability in VC for these pathogens among distinct Ae. aegypti populations in Argentina and demonstrate that accurate assessment of arbovirus risk will require nuanced models that fully consider the complexity of interactions between virus, temperature, mosquito genetics, and hosts.Fil: Ciota, Alexander T.. Wadsworth Center. State of New York Department of Health; Estados UnidosFil: Chin, Pamela A.. Wadsworth Center. State of New York Department of Health; Estados UnidosFil: Ehrbar, Dylan J.. Wadsworth Center. State of New York Department of Health; Estados UnidosFil: Micieli, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Fonseca, Dina M.. Center For Vector Biology, Rutgers University; Estados UnidosFil: Kramer, Laura D.. Wadsworth Center. State of New York Department of Health; Estados Unido

Vector competence of Aedes aegypti for different strains of zika virus in Argentina

The importance of Zika virus (ZIKV) has increased noticeably since the outbreak in the Americas in 2015, when the illness was associated with congenital disorders. Although there is evidence of sexual transmission of the virus, the mosquito Aedes aegypti is believed to be the main vector for transmission to humans. This species of mosquito has not only been found naturally infected with ZIKV, but also has been the subject of study in many vector competence assays that employ different strains of ZIKV around the world. In Argentina, the first case was reported in February 2016 and a total of 278 autochthonous cases have since been confirmed, however, ZIKV virus has not been isolated from any mosquito species yet in Argentina. In order to elucidate if Argentinian Ae. aegypti populations could be a possible vector of ZIKV, we conducted vector competence studies that involved a local strain of ZIKV from Chaco province, and a Venezuelan strain obtained from an imported case. For this purpose, Ae. aegypti adults from the temperate area of Argentina (Buenos Aires province) were fed with infected blood. Body, legs and saliva were harvested and tested by plaque titration on plates of Vero cells for ZIKV at 7, 11 and 14 days post infection (DPI) in order to calculate infection, transmission, and dissemination rates, respectively. Both strains were able to infect mosquitoes at all DPIs, whereas dissemination and transmission were observed at all DPIs for the Argentinian strain but only at 14 DPI for the Venezuelan strain. This study proves the ability of Ae. aegypti mosquitoes from Argentina to become infected with two different strains of ZIKV, both belonging to the Asian lineage, and that the virus can disseminate to the legs and salivary glands.Fil: Bonica, Melisa Berenice. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Goenaga, Silvina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Virales Humanas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Martin, María Laura. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Virales Humanas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Feroci, Mariel. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Virales Humanas; ArgentinaFil: Luppo, Victoria. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Virales Humanas; ArgentinaFil: Muttis, Evangelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Fabbri, Cintia. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Virales Humanas; ArgentinaFil: Morales, Maria Alejandra. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Virales Humanas; ArgentinaFil: Enria, Delia. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Virales Humanas; ArgentinaFil: Micieli, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Levis, Silvana del Carmen. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Virales Humanas; Argentin

Global genetic diversity of Aedes aegypti

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.Centro de Estudios Parasitológicos y de Vectore

Global genetic diversity of Aedes aegypti

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.Centro de Estudios Parasitológicos y de Vectore

Host range of the parasite Strelkovimermis spiculatus (Nematoda: Mermithidae) in Argentina mosquitoes

Strelkovimermis spiculatus (Poinar and Camino 1986) is a nematode parasite of mosquitoes isolated from the Neotropical region. We investigated the host range of this parasite in mosquito populations for a better understanding of the dynamics of temporary breeding sites. Five grassy-pool habitats filled by rainwater were sampled from the summer 2007 through the fall 2008. Eight mosquito species were collected: Anopheles albitarsis, Culex chidesteri, Culex dolosus, Culex maxi, Aedes albifasciatus, Psorophora ciliata, Psorophora cyanescens, and Psorophora albigenu. Six of these species were parasitized: Cx. chidesteri, Cx. dolosus, Cx. maxi, Ae. albifasciatus, Ps. ciliata, and Ps. cyanescens. The occurrence of this mermithid in natural mosquito populations was increased from the end of winter to the end of the spring. Prevalence ranged from 11% to 100%. High levels of infections were registered only in O. albifasciatus larvae, the most abundant mosquito species (95%), followed by Cx. dolosus (2.7%). Strelkovimermis spiculatus completed its development in all infected mosquito larvae. The presence of S. spiculatus in six natural mosquito populations increases the number of susceptible species to 24.Fil: Achinelly, Maria Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Estudios Parasitológicos y de Vectores (i); ArgentinaFil: Micieli, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Estudios Parasitológicos y de Vectores (i); Argentin