RESUMO
The main goals of the study were to carry out virus isolation attempts on Vero cell cultures from mosquitoes collected in southern Moravia (Breclav district, Czech Republic) and to identify the isolates using a microtiter virus neutralization test. A total of 9.742 female mosquitoes belonging to 13 species were examined, and three viral strains were isolated, all from the mosquitoes collected in 2006: two of these isolates were identified as Tahyna Orthobunyavirus (both obtained from Aedes vexans mosquitoes) and one was West Nile flavivirus (obtained from Aedes rossicus mosquitoes). Ae. rossicus might be a new vector for West Nile virus.
Assuntos
Arbovírus/isolamento & purificação , Culicidae/virologia , Animais , República TchecaRESUMO
Six viral isolates were obtained from 23,243 female mosquitoes (examined in 513 pools) belonging to 16 species and collected along the lower reaches of the Dyje River in South Moravia (Czech Republic, central Europe) during 2006-2008: five isolates of Orthobunyavirus Tahyna (TAHV, California group, family Bunyaviridae: three isolations from Aedes vexans (Meigen), one from Ae. sticticus (Meigen), one from Culex modestus Ficalbi); and one isolation of Flavivirus West Nile (WNV, Japanese encephalitis group, family Flaviviridae)-strain Rabensburg (proposed lineage 3 of WNV) from Ae. rossicus (Dolbeshkin et al). All viral isolates were recovered from mosquitoes collected in 2006 (15,882 mosquitoes examined), while no virus was isolated from mosquitoes trapped in 2007 and 2008, when 1,555 and 5,806 mosquitoes were examined, respectively. The population density of local mosquitoes was very low in 2007 and 2008 because of warm and dry summer including a considerably low water table, compared with environmental conditions favorable for mosquito development in 2006. The virus isolation procedure was based on intracerebral inoculation of newborn mice. In parallel, more than one-third of the samples (183 pools consisting of 8,470 individual mosquitoes) were also examined by inoculating Vero cell cultures in Leighton tubes. However, the latter method detected only three of the six virus isolates (including WNV-Rabensburg). Ae. rossicus is a new potential vector for WNV-Rabensburg. This species feeds mostly on mammals including man; this raises the question whether this virus lineage is not adapted to an alternative mosquito-mammal cycle in the South-Moravian natural focus.