A relatively new equine pathogen on the scene called coronavirus causes gastrointestinal illness, but not in every horse that has it. And because it bears some similarities to its viral cousin, bovine coronavirus, which in cows causes mild respiratory signs in addition to the gastrointestinal ones, equine researchers wondered if there’s a subset of horses getting a respiratory form of the virus, and, if so, could it present a diagnostic opportunity.

Nicola Pusterla, DVM, PhD, Dipl. ACVIM, a professor at the University of California, Davis, School of Veterinary Medicine, and colleagues conducted a study to find out if equine coronavirus (ECoV), which can be detected in infected horses’ feces, can colonize horses’ respiratory tracts and, as such, be isolated from their nasal secretions. So. He presented their results at the 2015 American Association of Equine Practitioners’ Convention, held Dec. 5-9 in Las Vegas.

Common signs of ECoV infection in adult horses include anorexia, lethargy, and fever; less common signs include diarrhea, colic, and neurologic deficits. Infected horses can develop complications, including septicemia (infection in the bloodstream), endotoxemia (endotoxin), and encephalopathy (brain disorder, in this case caused by abnormally high ammonia levels in the blood), all of which are associated with gastrointestinal tract (enteric) barrier breakdown. Many infected horses develop illness, but few die as a result, and the disease often resolves on its own.

Pusterla said ECoV is closely related to bovine coronavirus, which can cause both respiratory and enteric disease. He and colleagues wondered if ECoV might a