Equine coronavirus: An emerging enteric virus of adult horses.
Authors: Pusterla N, Vin R, Leutenegger C, Mittel L D, Divers T J
Journal: Equine veterinary education
Summary
# Equine Coronavirus: An Emerging Enteric Threat Equine coronavirus (ECoV) has emerged as a clinically significant pathogen in adult horses since 2010, presenting with fever, depression and anorexia, with some cases progressing to colic or diarrhoea; the virus spreads faeco-orally between horses and is increasingly documented across Japan, North America and Europe. Clinical suspicion can be strengthened by identifying leucopenia with lymphopenia or neutropenia on haematological examination, though definitive diagnosis requires quantitative PCR detection of viral nucleic acid in faeces or antigen demonstration via immunohistochemistry on intestinal biopsies. Whilst most infected horses recover with supportive care alone, secondary complications arising from gastrointestinal barrier disruption—including endotoxaemia, septicaemia and hyperammonaemia-associated encephalopathy—can occur in a subset of cases and warrant close monitoring. Prevention currently relies on conventional biosecurity measures, as vaccination strategies effective against related coronaviruses (such as bovine coronavirus) have not yet been investigated in equines. Practitioners should maintain high clinical suspicion when presented with adult horses exhibiting systemic signs with gastrointestinal involvement, particularly during periods of increased case reporting, and recognise that faecal shedding from both symptomatic and asymptomatic horses poses transmission risk across yards and competition venues.
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Practical Takeaways
- •Recognise ECoV in adult horses presenting with fever, depression, and anorexia; submit faecal samples for qPCR confirmation rather than relying on clinical signs alone
- •Implement strict biosecurity protocols including faecal-oral precautions, as no specific vaccine or immunoprophylactic measures are currently available for horses
- •Monitor for complications such as endotoxaemia and hyperammonaemia-associated encephalopathy in infected horses, as these significantly impact prognosis beyond the primary viral infection
Key Findings
- •Equine coronavirus is an emerging enteric virus causing fever, depression, anorexia, and less frequently colic and diarrhoea in adult horses with increased frequency since 2010
- •Diagnosis is confirmed by quantitative PCR detection of ECoV nucleic acid in faeces or demonstration of coronavirus antigen by immunohistochemistry/electron microscopy in intestinal tissue
- •The disease is generally self-limiting with symptomatic supportive care, though complications including endotoxaemia, septicaemia, and hyperammonaemia-associated encephalopathy can occur
- •Faeco-oral transmission route is suspected with clinical and asymptomatic infected horses serving as sources of direct and indirect transmission