Horse owners should be vigilant about having equine survivors of West Nile virus (WNV) re-examined by their veterinarians before putting the animals back into work. In a study of Minnesota horses which survived clinical WNV can make the horse more dangerous to ride or drive. Julia Wilson, DVM, Dipl. ACVIM, Associate Professor in Clinical and Population Sciences at the University of Minnesota’s (UM) College of Veterinary Medicine, presented this statistic and other results from her study examining residual effects of WNV on horses to better characterize prognosis at the 2003 American Association of Equine Practitioners’ Convention.

Her research group collaborated with the Minnesota Department of Health and the Minnesota Board of Animal Health to obtain data on surviving horses with a confirmed WNV diagnosis. Two hundred owners were sent questionnaires in early 2003 and were asked to characterize the horse’s use pre- and post-infection, the horse’s infection, 40% showed residual effects attributed to WNV at six months after diagnosis; these neurological effects current neurologic status, length of recovery, observations of relapse or recurrence of clinical signs, to check off any of the listed 11 abnormalities that were currently observable, and to comment on any additional concerns regarding the horse