[The presence of Culicidae species in medium-sized cities in the State of São Paulo, Brazil and the risk of West Nile fever and other arbovirus infection]. / Presença de culicídeos em município de porte médio do Estado de São Paulo e risco de ocorrência de febre do Nilo Ocidental e outras arboviroses.

INTRODUCTION: The objectives for this study were to measure the diversity of Culicidae species, describe their abundance and seasonal variation in São José do Rio Preto, SP, and discuss the risk of arbovirus infections. METHODS: The collection of larval and adult mosquitoes was conducted monthly from 2006 to 2007 in an urban area and four sections of forested land. In the urban area, larvae were collected from sites where oviposition by Culex mosquitoes was most likely to occur. At two of the four sites in the forested land, adult mosquitoes were collected with the use of CDC traps at night, and a Nasci aspirator was used in the daytime at the two other collection sites. RESULTS: In the urban area, 34 Culicidae species were identified out of a total sample of 8,683 specimens; of these specimens, 80.7% were Culex quinquefasciatus, 9.6% were Culex coronator, 3.2% were Aedes albopictus, and 1.1% were Ochlerotatus fluviatilis. The abundance of Cx. quinquefasciatus larvae was negatively related to rainfal. In the woods, 2,268 mosquitoes were collected, representing 10 genera and 46 species. The most abundant mosquito species were Aedeomyia squamipennis, Culex coronator, Culex (Mel.) Melanoconion section, Culex declarator, Ochlerotatus scapularis, Anopheles triannulatus, Culex bidens/interfor and Culex habilitator/pseudojhantinosoma. CONCLUSIONS: The abundance of Cx. quinquefasciatus in the urban area and the presence of other Culicidae species in urban areas and forested land point to the possibility of the transmission of West Nile virus and other arbovirus infections in São José do Rio Preto and other cities. Thus, the enacting of measures aimed at the surveillance of these arbovirus infections is essential.