WNV transmission occurs when infected mosquitoes feed on animals, as well as humans, after having fed on infected birds. | Photo: Photos.com

On Sept. 30, officials at the California Department of Food and Agriculture (CDFA) confirmed an unvaccinated 2-year-old pony colt in Nevada County as positive with West Nile virus (WNV). The colt, which is reported as affected and alive, experienced onset of neurologic signs that included ataxia (loss of muscle control) and recumbency (down and unable to rise) on Sept. 25.

According to a CDFA statement, the colt marks the state’s 14th confirmed equine case this year. The positive horses were located in the following counties:

• Amador (1)
• Butte (1)
• Glenn (1)
• Kings (1)
• Merced (1)
• Nevada (1)
• Riverside (2)
• San Bernardino (1)
• San Joaquin (2)
• Stanislaus (3)

Of those horses affected, eight were unvaccinated, four had unknown vaccination histories, and two were vaccinated. Eleven horses remain alive. One horse died and two were euthanized