Serologic survey of wild boars for mosquito-borne viruses in South Moravia (Czech Republic)

Abstract

A serosurvey for mosquito-borne viruses was carried out in 93 wild boars (Sus scrofa), using a plaque-reduction neutralization microtest with Vero cells. The boars were sampled on 24 hunting grounds of the Breclav district (South Moravia) from 2000 to 2002. Specific antibodies to Flavivirus West Nile (WNV) were detected in six (6.5%) animals, and only in Lanzhot and Kostice, i.e., in the area of the "Soutok" game reserve where WNV was previously isolated from mosquitoes in South Moravia. However, the antibody titres were comparatively low (1:20-1:40). A substantially higher seroprevalence was revealed against Orthobunyavirus Tahyna (TAHV): 18 (19.4%) wild boars were positive, and the titres ranged from 1:20 up to 1:640. Only one animal (1.1%) seroreacted with Orthobunyavirus Batai (Calovo), at a low titre of 1:20. The sera were additionally examined by a haemagglutination-inhibition test against Alphavirus Sindbis: two boars (2.2%) revealed antibodies, the titres were 1:20 and 1:80. The serosurvey indicates that the activity of mosquito-borne viruses in South Moravia has decreased compared with the past decades, but that surveillance for these viruses is still necessary.