Silent circulation of dengue virus in Aedes albopictus (Diptera: Culicidae) resulting from natural vertical transmission.

Vertical transmission in Aedes aegypti and Aedes albopictus is considered a maintenance mechanism for dengue virus (DENV) during unfavorable conditions and may be implicated in dengue outbreaks. Since DENV infection dynamics vary among wild-type viruses and vector populations, vertical transmission rates can also vary between regions. However, even though São Paulo is the most populous city in the Americas and has experienced major dengue epidemics, natural vertical transmission had never been detected in this area before. Here we confirm and describe for the first time natural vertical transmission of DENV-3 in two pools of male Ae. albopictus from the city of São Paulo. The detection of DENV-3 in years when no human autochthonous cases of this serotype were recorded suggests that silent circulation of DENV-3 is occurring and indicates that green areas may be maintaining serotypes that are not circulating in the human population, possibly by a vertical transmission mechanism.

Gonotrophic discordance in Culex quinquefasciatus (Diptera: Culicidae) in the city of São Paulo, Brazil

Abstract INTRODUCTION: This study aimed to assess the occurrence of gonotrophic discordance in females of Culex quinquefasciatus in São Paulo, Brazil. METHODS: Resting females were collected monthly for 8 months. Females of Cx. quinquefasciatus were identified, and their midgut and ovaries were dissected. RESULTS: Two hundred females were dissected, out of which, 27.5% were nulliparous and 57% were parous. Most females had no blood in the midgut, but gonotrophic discordance was found in 21% females. CONCLUSIONS: Females of Cx. quinquefasciatus showed a high parity rate and gonotrophic discordance, which could favor the vector capacity of this species.

Gonotrophic discordance in Culex quinquefasciatus (Diptera: Culicidae) in the city of São Paulo, Brazil.

INTRODUCTION: This study aimed to assess the occurrence of gonotrophic discordance in females of Culex quinquefasciatus in São Paulo, Brazil. METHODS: Resting females were collected monthly for 8 months. Females of Cx. quinquefasciatus were identified, and their midgut and ovaries were dissected. RESULTS: Two hundred females were dissected, out of which, 27.5% were nulliparous and 57% were parous. Most females had no blood in the midgut, but gonotrophic discordance was found in 21% females. CONCLUSIONS: Females of Cx. quinquefasciatus showed a high parity rate and gonotrophic discordance, which could favor the vector capacity of this species.

Mosquito (Diptera: Culicidae) fauna in parks in greater São Paulo, Brazil / Fauna de mosquitos (Diptera: Culicidae) em parques da cidade de São Paulo, Brasil

Municipal parks in the city of São Paulo, which are used for leisure purposes, contain remnants of the flora of the Atlantic Forest, as well as lakes and springs, and are home to mammals, birds and arthropods, some of which can be vectors of disease. The eastern side of the city has the largest population in São Paulo and twenty-four municipal parks. The aim of this study was to investigate Culicidae fauna in two parks on this side of the city and to determine which of the Culicidae species identified have the potential to act as bioindicators and vectors of human pathogens. Culicidae were collected monthly between March 2011 and February 2012 in Carmo Park and Chico Mendes Park with battery-powered aspirators, Shannon traps and CDC traps for adult mosquitoes, and larval dippers and suction samplers for immature mosquitoes. To confirm sample sufficiency, the EstimateS program was used to plot sample-based species accumulation curves and estimate total richness by the Jackknife 1 method. In all, 1,092 culicids from nine genera (Aedes, Anopheles, Coquillettidia, Culex, Limatus, Mansonia, Trichoprosopon, Toxorhynchites and Uranotaenia) and nineteen taxonomic units were collected in Carmo Park. Coquillettidia venezuelensis (Theobald 1912), Aedes scapularis (Rondani 1848) and Culex (Culex) spp. Linnaeus 1758 were the most abundant adults, and Culex (Melanoconion) spp. Theobald 1903 and Anopheles strodei Root 1926 the most abundant immature mosquitoes. In Chico Mendes Park 4,487 mosquitoes in six genera and eighteen taxonomic units were collected. Culex (Cux.) spp. and Ae. scapularis were the most abundant adults, and Ae. albopictus (Skuse 1984) the most abundant immature mosquitoes. The species accumulation curves in both parks were close to the asymptote, and the total richness estimate was close to the observed richness. Some culicid taxons are bioindicators of environmental conditions in the areas they inhabit. It is important to monitor native fauna in municipal parks in São Paulo as various species in this study were found to have vector competence and capacity to transmit pathogens, such as arboviruses.

Em São Paulo os parques municipais preservam resquícios da vegetação de Mata Atlântica, comportam lagos e nascentes, servem de abrigos para mamíferos, aves e artrópodes vetores. São frequentados pela população humana como ambientes de lazer. A zona Leste da cidade possui o maior índice populacional de habitantes e 24 parques municipais. O objetivo deste trabalho foi conhecer a fauna de Culicidae de dois parques da zona Leste da cidade e avaliar a presença de espécies potencialmente bioindicadoras e vetoras de patógenos ao homem. Foram feitas coletas mensais de culicídeos entre março de 2011 a fevereiro de 2012 no Parque do Carmo e no Parque Chico Mendes, com aspiradores elétricos, armadilhas de Shannon e CDC para mosquitos adultos e concha entomológica e bombas manuais de sucção para os imaturos. Para verificar a suficiência amostral foram construídas curvas de acúmulo de espécies por amostragem e a riqueza total foi estimada pelo método Jackknife 1, ambos gerados pelo programa EstimateS. No parque do Carmo foram coletados 1.092 culicídeos, distribuídos em nove gêneros (Aedes, Anopheles, Coquillettidia, Culex, Limatus, Mansonia, Trichoprosopon, Toxorhynchites e Uranotaenia), distribuídos em 19 unidades taxonômicas. Coquillettidia venezuelensis(Theobald 1912), Aedes scapularis (Rondani 1848)e Culex (Culex) spp. Linnaeus 1758 foram os adultos mais abundantes e Culex (Melanoconion) spp. Theobald 1903 e Anopheles strodei Root 1926 os imaturos. No Parque Chico Mendes obteve-se 4.487 mosquitos, distribuídos em seis gêneros e 18 unidades taxonômicas. Culex (Cux.) spp. e Ae. scapularis foram os mais abundantes dos adultos e Ae. albopictus (Skuse 1984) dos imaturos. As curvas de acúmulo de espécies por amostragem em ambos os parques chegaram próximas è assíntota e a estimativa de riqueza total mostrou-se próxima è riqueza observada. Alguns táxons de culicídeos são bioindicadores das condições ambientais dos locais onde vivem, portanto é necessário acompanhar a fauna nativa dos parques municipais porque várias espécies encontradas têm mostrado competência e capacidade para veicular patógenos e arbovírus.