Disease progression, pathologic, and virologic findings of an equine influenza outbreak in rescue donkeys.
Authors: Ahearne Megan M, Pentzke-Lemus Ligia L, Romano Ashley M, Larsen Eileen D, Watson Allison M, O'Fallon Elsbeth A, Landolt Gabriele A
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: Equine Influenza in Rescue Donkeys Equine influenza virus (EIV) is a well-recognised respiratory pathogen in horses, yet clinical data describing its presentation and progression in donkeys remain sparse. Researchers at Colorado State University retrospectively analysed 13 unvaccinated donkeys (aged 1 week to 12 years) presenting with clinical signs consistent with EIV infection during a 2020 outbreak, confirming diagnosis through molecular testing, viral isolation, and phylogenetic sequencing of a contemporary clade 1 Florida sublineage H3 virus. Whilst clinical manifestations mirrored those typically seen in equine cases, survival outcomes differed markedly by age: donkeys younger than 1 year achieved only 16.6% survival (1/6 animals) compared with 85.7% survival (6/7) in older animals, with deaths concentrated in foals born to seronegative dams. These findings underscore a critical vulnerability in neonatal donkeys lacking maternally-derived immunity and highlight a significant gap in vaccination practice, suggesting that prenatal EIV vaccination protocols—currently standard in horse breeding programmes—warrant equivalent consideration across all equid species to prevent catastrophic foal mortality during outbreaks.
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Practical Takeaways
- •Young unvaccinated donkeys, especially foals from seronegative dams, have significantly higher mortality from equine influenza and require proactive protection strategies
- •Prenatal vaccination protocols should be extended to all equids including donkeys, not just horses, to provide passive immunity in foals
- •Clinical presentation of equine influenza in donkeys mirrors horses, so similar diagnostic and treatment approaches should be applied in donkey populations
Key Findings
- •Survival rate in donkeys <1 year old was 16.6% (1/6) compared to 85.7% (6/7) in animals >1 year old
- •Clinical signs of equine influenza in donkeys are similar to those in horses
- •A contemporary clade 1 Florida sublineage H3 virus was confirmed as the causative agent
- •Deaths were particularly observed in foals born to seronegative dams, highlighting vulnerability in unvaccinated neonates