SEROPREVALENCE OF WEST NILE VIRUS IN BULGARIA, 2018

In Bulgaria, the first laboratory-confirmed West Nile neuroinvasive disease (WNND) case occurred in 2015 and more cases have been reported ever since. The aim of our study was to track the current circulation of West Nile virus (WNV) in the country. We collected 1830 serum samples from healthy people of every district in Bulgaria. Commercially available ELISA kits were used to detect specific anti-WNV IgG antibodies. All positive samples were tested for specific IgM antibodies using the same method. Possible risk factors were identified by calculating odds ratio. Specific IgG antibodies were detected in 22 of the samples (1.2%, CI 0.8% to 1.8%). No IgM antibodies were detected in the positive samples. The highest seroprevalence rates were found in the districts of Pleven, Varna, Silistra and Yambol. This study showed the continuous circulation and spread of WNV in Bulgaria