[Mosquito complex (Diptera, Culicidae) in a West Nile fever focus in the Volgograd region. I. Species diversity and relative abundance in different habitats].

Potential West Nile virus (WNV) vectors were assessed during 2003 and 2004 at the indoor and outdoor collection sites of Volgograd and surrounding rural areas. A total of 26 387 female mosquitoes comprising 16 species in 5 genera of the subfamily Culicinae and 4 species of the subfamily Anophelinae were collected. The seasonal abundance and the dominance structure greatly differed in the multi-storied buildings, farms, and open habitats whereas the similarity of species diversity remained high throughout the season. In the porches of buildings, Aedes vexans (58%) and Cx. pipiens (37%) prevailed in early July (the beginning of a transmission period), Cx. pipiens (92%) was an absolute dominant species in August. The autogenous form of Cx. pipiens was most common in the flooded-basement houses of the city's outskirts. The number of anautogenous females in the indoor collections increased by August. Only the anautogenous form of Cx. pipiens was sampled in the open rural and urban areas. The findings suggest that the attraction of potential vectors, including anautogenous Cx. pipiens, from the outdoor biotopes to the porches of apartment houses is one of the main reasons for the spread of the disease in the urban population.