Evidence of the first clinical case of equine neuroinvasive West Nile disease in Serbia, 2018

During July 2018, the first clinical case of neurological West Nile virus (WNV) infection was reported in a Belgian sports mare in Belgrade, Serbia. Typical symptoms, such as hypersensitive skin reaction, disorientation, weakness, ataxia and the loss of equilibrium were reported. Detection of WNV IgM antibodies by commercial ELISA in the serum samples of the diseased mare strongly indicated acute infection. The ELISA positive results were confirmed by VNT. Hematological and biochemical parameters were in the reference range. The only finding was a minor lymphopenia. WNV RNA was not detected by RT-qPCR in the blood sample extracted seven days after the disease had broken out. The horse improved clinically in two weeks while other horses at the same premises remained asymptomatic. The clinical, serological, biochemical and molecular analyses applied confirmed the first clinical case of neuroinvasive WNV infection in horses in Serbia. The West Nile virus has been circulating in Serbia in the last decade in mosquitoes, birds, and horses, but no evidence of equine WNV clinical cases were registered so far.