West Nile virus confirmed in horses across three US states

New cases of West Nile virus (WNV) have been confirmed in horses across Idaho, Indiana, and Louisiana. All horses that tested positive were unvaccinated.

In Bannock County, Idaho, a 5-year-old Quarter Horse mare tested positive on August 12 after exhibiting mild ataxia. In Porter County, Indiana, a 19-year-old Miniature Horse mare tested positive on August 8; she is currently recovering from symptoms including ataxia and muscle fasciculations. In East Baton Rouge, Louisiana, a yearling Quarter Horse colt tested positive on August 14 and is also recovering.

West Nile virus is transmitted to horses through mosquito bites. While there is no cure, some horses can recover with supportive care. Equine mortality rates for the virus can reach between 30% and 40%. Experts note that vaccines are effective prevention tools, though they require annual boosters.