FieldDxEquine Coronavirus InfectionClinical signs, differential diagnosis, treatment and prevention in horses.
Overview
An enteric viral infection of adult horses, usually self-limiting. Equine coronavirus (ECoV).
Clinical signs
- Fever (38.6–41.1°C / 101.5–106°F), anorexia and lethargy; short incubation of 48–72 hours.
- Colic and diarrhea in about 10–15% of cases.
- Severe complications (shock, organ failure, neurological signs) in roughly 7% of cases; some horses remain subclinical.
Predisposing factors
- Spreads by the faecal-oral route through contaminated feed and water.
- More cases from October to April, in colder months.
- Draft horses had the highest seroprevalence odds of the breeds tested and Thoroughbreds the lowest; the Midwest and ranch, farm and breeding horses had higher odds.
- Clinical cases are mostly adults; disease appears 48-72 hours after exposure and faecal shedding lasts 3-25 days.
Treatment
- No specific antiviral treatment exists; management is supportive with NSAIDs (flunixin meglumine or phenylbutazone), IV fluids and electrolytes, and gastrointestinal protectants.
- Most adult horses recover fully within days; morbidity is high but mortality is low.
Drugs mentioned: Flunixin Meglumine Phenylbutazone Flunixin
Prevention
1. There is no licensed vaccine. 2. Isolate febrile horses (38.5°C or above) with anorexia or lethargy until a laboratory diagnosis is made; if PCR confirms infection, keep the isolation and quarantine the source stable. 3. Ideally isolate new arrivals for at least 3 weeks. 4.
Source
Veterinary Journal, Pusterla N et al. (2018), Enteric coronavirus infection in adult horses, via PubMed Central — Enteric coronavirus infection in adult horses (accessed 2026-10-29)
UC Davis School of Veterinary Medicine — Equine Coronavirus (accessed 2026-08-11)
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