The 2011 mosquito-borne disease season continues to affect horse owners across the country. The most recent reports indicate Hthat a horse in California and a horse in Nevada have both tested positive for West Nile virus (WNV).

In 2010, the USDA’s National Animal Health Surveillance System reported 125 confirmed cases of WNV in 28 states.

According to the California West Nile Virus Website (produced by the California Department of Public Health, the University of California Davis Center for Vectorborne Diseases, the California Department of Food and Agriculture, and the Mosquito and Vector Control Association of California), a horse in Los Angeles county recently became the first horse in the state to be confirmed WNV-positive in 2011.

Additionally, a horse in Lyon County, Nev., was confirmed WNV-positive by the Nevada Department of Agriculture’s Animal Disease and Food Safety Laboratory earlier this week, according to a news report from The Record Courier. In the report, Nevada State Veterinarian Phil LaRussa, DVM, encouraged horse owners to seek vaccination for unvaccinated horses, noting that there are numerous products available for all classes of horses