Equine Rhinitis Virus Prevalence in Louisiana Racehorses Evaluated

Infectious respiratory diseases such as equine influenza and equine herpesvirus can have a significant welfare and economic effect on the horse industry, and researchers and veterinarians have devoted much time and money to trying to control and prevent outbreaks. Far less is known, however, about another infectious respiratory disease: equine rhinitis virus (ERV).

Frank Andrews, DVM, MS, Dipl. ACVIM, professor and director of the Equine Health Studies Program at Louisiana State University School of Veterinary Medicine, and colleagues recently conducted a study to determine the seroprevalence (the frequency of individuals in a population that have positive serum antibodies in their blood) of ERV serotypes ERAV-1 and ERBV-1 in a population of racehorses at Louisiana tracks and training facilities. Andrews presented their results at the 2012 International Equine Conference of Equine Infectious Diseases, held Oct. 21-26 in Lexington, Ky.

In their study, the research team collected and analyzed blood samples from 77 horses housed at a Louisiana racetrack, 44 horses at a Louisiana Thoroughbred training facility, and 55 at the Louisiana State University Equine Health Studies Program Thoroughbred and Quarter Horse research and teaching farm. They noted serum antibodies to ERAV-1 and ERBV-1 in 84.1% and 94.9%, respectively, of the horses at all three facilities.

They also found that serum neutralization (SN) titers (the concentration of specific antibodies in the blood that recognize an agent such as ERV) for ERAV-1 were significantly higher in horses at the racetrack and at the university when compared to horses at the training center.

"The difference in SN titers at these facilities was not apparent but may be due to age, as horses at the racetrack and university farm were older, allowing more time for virus exposure and antibody production," the researchers explained.

In conclusion they said, "ERV appears to be prevalent in horses in Louisiana and warrants further epidemiologic investigation to determine its impact on racing and training and the need for vaccine development to reduce impact."

Owners of racehorses and other horses that have co-mingled at barns and events should keep an eye out for clinical signs of infectious respiratory diseases such as ERV, including nasal discharge, fever, and cough, and implement smart biosecurity practices to prevent potential disease spread.

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.