Evidence of West Nile Virus Circulation in Horses and Dogs in Libya

West Nile virus (WNV) is a global important mosquito-borne Flavivirus causing West Nile disease (WND). In Libya, evidence of WNV circulation has been reported in humans but never in animals. The aim of this study was to determine the seroprevalence of the WNV infection in horses and dogs in Libya. A total of 574 and 63 serum samples from horses and dogs, respectively, were collected from healthy unvaccinated animals between 2016 - 2019. A commercially available competitive ELISA (c-ELISA) kit was initially used to test the collected samples for the presence of WNV Ig-G antibodies. Positive and doubtful sera were also tested by using the more specific virus neutralization assays to confirm whether the ELISA positive results were due to WNV or Usutu virus (USUV) antibodies. The seroprevalence of WNV IgG ELISA antibodies was 13.2% (76/574) and 30.2% (19/63) in horses and dogs, respectively. Virus neutralization test (VNT) showed that 77.5% (62/80) and 89.5% (17/19) of positive and doubtful horse serum samples and dogs serum samples, respectively, were positive with WNV neutralising titers ranging from 1:10 to 1:640. The results of the present study provided novel evidence about the WNV circulation in Libya.