Novel findings from a beta coronavirus outbreak on an American Miniature Horse breeding farm in upstate New York.
Authors: Goodrich E L, Mittel L D, Glaser A, Ness S L, Radcliffe R M, Divers T J
Journal: Equine veterinary education
Summary
# Editorial Summary A 2013 outbreak of equine beta coronavirus on an American Miniature Horse breeding farm in upstate New York provided unexpected insights into BCoV epidemiology and transmission dynamics. The farm housed 29 miniature horses and one donkey when the outbreak occurred in January–February, with infection also confirmed in a Quarter Horse mare kept off-site by farm staff; faecal samples were analysed using PCR to confirm BCoV detection. Notably, this represented the largest closed-herd BCoV outbreak documented at the time, yet achieved a zero fatality rate—contrasting sharply with previous miniature horse outbreaks—whilst demonstrating morbidity rates lower than earlier published cases. Perhaps most significantly, several asymptomatic horses shed virus in their faeces for extended periods, substantially longer than documented in symptomatic ECoV cases, and the outbreak demonstrated transmission via farm personnel, suggesting that clinically normal carriers may maintain viral circulation during an outbreak period. For equine practitioners, these findings underscore the importance of screening both symptomatic and apparently healthy horses on affected premises and implementing rigorous biosecurity protocols, as subclinical shedding can sustain infection spread even when clinical disease appears controlled.
Read the full abstract on PubMed
Practical Takeaways
- •Test both clinically affected and apparently normal horses on a premises during suspected coronavirus outbreaks, as asymptomatic animals may shed virus longer than expected
- •Implement strict biosecurity protocols for farm personnel movement between horses, as BCoV can be transmitted via human contact despite lack of visible clinical signs
- •Do not assume lower morbidity rates indicate lower transmission risk—asymptomatic carriers may play a significant role in virus maintenance on premises
Key Findings
- •Largest outbreak of BCoV in a closed herd on a single premises with 29 American Miniature Horses and 1 donkey affected, with 0% case fatality rate
- •Morbidity rate was lower than previously described ECoV outbreaks despite similar farm conditions
- •Virus shedding duration in feces of asymptomatic horses was longer than previously documented in clinical ECoV cases
- •BCoV transmission occurred via farm personnel, indicating a potential biosecurity risk pathway