Equine herpesvirus outbreak is officially over, USDA veterinarians say

Jul 01, 2011
By dvm360.com staff
National Report — An outbreak of equine herpesvirus (EHV-1) that raced through 12 Western states in late spring officially came to an end.

The U.S. Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS) released its final report on the outbreak June 23, saying the outbreak has been contained and no new premises are affected.

The final tally for the outbreak, according to APHIS, was 90 cases. Two late-breaking cases reported in Montana and Wyoming by animal-health officials did not make APHIS’ final tally.

A total of 57 horses—28 with primary infections and 29 with secondary infections—were confirmed infected with EHV-1 by APHIS. Another 33—26 primary cases and seven secondary cases—of equine herpesvirus myeloencephalopathy (EHM) also were confirmed by the agency. Thirteen more horses were euthanized or died during the outbreak.

The outbreak began at a National Cutting Horse Association (NCHA) competition in Ogden, Utah, between April 29 to May 8. More than 400 horses in 19 states were exposed to the virus, and another 1,685 have been exposed by association, APHIS says.