BackgroundAmerican tegumentary leishmaniasis is a serious Brazilian public health problem. This diseases is attributed to seven species of Leishmania, however, the majority of cases are associated with Leishmania braziliensis. Some phlebotomine species have been implicated in the transmission of this parasite, nonetheless only Psychodopygus wellcomei has had its vectorial competence demonstrated. Thus this study sought to assess some parameters related to the vectorial capacity of anthropophilic species of sand fly occurring in São Paulo state: Pintomyia fischeri, Migonemyia migonei Nyssomyia intermedia, Nyssomyia whitmani, Expapillata firmatoi and Psychodopygus ayrozai, under laboratory conditions. These parameters were the duration of the gonotrophic cycle, proportion of females which feed on hamster, the rate of infection by L. braziliensis and the duration of the extrinsic incubation period.MethodsThe sandflies were collected in three regions of the São Paulo state: Greater São Paulo and the Mogi Guaçu and Iporanga municipalities. To assess the proportion of engorged females the insects were fed on hamsters to estimate the duration of the gonotrophic cycle. To estimate the susceptibility to infection of each species, their females were fed on hamsters infected with Leishmania braziliensis and dissected to ascertain the localization of the flagellates and estimate the extrinsic incubation period.ResultsLow hamster attractiveness to Ps. ayrozai was observed. A high proportion of engorged females was observed when the hamster had its whole body exposed. The gonotrophic cycle ranged between three and eight days. Mg. migonei, Pi. fischeri, Ny. neivai, Ny. intermedia, Ny. whitmani and Ex.firmatoi presented susceptibility to infection by L. braziliensis. The highest infection rate (34.4%) was observed for Ny. whitmani and the lowest for Ny. intermedia (6.6%). Mg. migonei presented late-stage infection forms on the fifth day after feeding, but in the other species these forms were observed as from the fourth day.ConclusionsOur results, together with other parameters of their behavior under natural conditions, suggest the potential role of Ex. firmatoi as vector of this parasite and reinforce that of Mg. migonei, Pi. fischeri, Ny. neivai, Ny. intermedia and Ny. whitmani in the areas in which they occur.

BackgroundAedes aegypti is the main vector of the dengue, Zika and several other arboviruses. It is highly adapted to urbanized environments and can be found worldwide. Mosquito population control is considered the best strategy for fighting mosquito-borne diseases, making an understanding of their population dynamics vital for the development of more effective vector control programs. This study therefore sought to investigate how different levels of urbanization affect Aedes aegypti populations and modulate population structure in this species with the aid of wing geometric morphometrics.MethodsSpecimens were collected from eleven locations in three areas with distinct levels of urbanization in the city of São Paulo, Brazil: conserved, intermediate and urbanized. The right wings of female mosquitoes collected were removed, and photographed and digitized. Canonical variate analysis and Mahalanobis distance were used to investigate the degree of wing-shape dissimilarity among populations. Thin-plate splines were calculated by regression analysis of Canonical Variation Analysis scores against wing-shape variation, and a cross-validated reclassification was performed for each individual; a neighbor-joining tree was then constructed.ResultsMetapopulation and individual population analysis showed a clear segregation pattern in the Canonical Variation Analysis. Pairwise cross-validated reclassification yielded relatively high scores considering the microgeographical scale of the study and the fact that the study populations belong to the same species. The neighbor-joining tree showed that mosquitoes in the intermediate urban area segregated in the metapopulation and individual population analyses. Our findings show significant population structuring in Aedes aegypti mosquitoes in the areas studied. This is related to the different degrees of urbanization in the areas where the specimens were collected along with their geographical location.ConclusionsUrbanization processes in the study areas appear to play an important role in microevolutionary processes triggered by man-made modifications in the environment, resulting in a previously unknown population structuring pattern of major epidemiological importance.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-3154-4) contains supplementary material, which is available to authorized users.

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.

Ao meu orientador Dr. Paulo Roberto Urbinatti. Foi um presente poder desenvolver esse trabalho sob sua orientação, sua imensa generosidade me ensinou a ser uma pessoa melhor. Por tudo obrigada! Aos diretores da Faculdade de Saúde Pública/USP, Dra. Helena Ribeiro e Dr. Victor Wünsch Filho, pela concessão do transporte da equipe da FSP/USP até a Cidade Universitária. À Prefeitura do Campus USP da Capital, SP, pela disponibilização de espaço físico e equipe de campo para realização das coletas. Agradecimento especial a Bióloga, Dra. Daniella Vilela Lima, ao Biólogo Dr. Ricardo Prist, da Seção de Controle de Vetores, da Prefeitura do Campus USP; aos servidores da Prefeitura, José Cícero da Silva e Wilson Wanderley (Sasá). Aos alunos bolsistas do SGA: Isabela Castro Ramos e Luís Gustavo Lopumo Arruda, pelo auxílio nos trabalhos de campo. Ao Biólogo Aristides Fernandes, pelas dúvidas sanadas, quanto ao diagnóstico das espécies de culicídeos. Aos meus amigos de laboratório Marta, Filipe, Ronan e Pâmela, obrigada pela ajuda, colaboração, e acima de tudo pela amizade construída, obrigada! À Rosa Maria M. de Sá Almeida, Técnico de Laboratório da FSP/USP, pela disposição em me ajudar nas atividades de laboratório. À minha amiga Cecília Lavistchika pela amizade sincera, generosidade e ajuda preciosa. Ao Dr. Everton Falcão pela colaboração nas análises estatísticas e pela disponibilidade em dividir seus conhecimentos. Ao Profº Dr. Francisco Chiaravalloti-Neto do Departamento de Epidemiologia da FSP/USP pela colaboração na produção dos mapas.