An epidemiological overview of the equine influenza epidemic in Great Britain during 2019.
Authors: Whitlock Fleur, Grewar John, Newton Richard
Journal: Equine veterinary journal
Summary
# Editorial Summary: The 2019 Equine Influenza Epidemic in Great Britain During 2019, Great Britain experienced a significant equine influenza outbreak affecting 234 premises with 412 laboratory-confirmed cases, predominantly occurring in two waves between January and August. Whitlock and colleagues conducted a retrospective epidemiological analysis by collating veterinary laboratory data and premises-level information, using spatial mapping and logistic regression to identify risk factors associated with infection during the first epidemic phase. The outbreak predominantly affected unvaccinated animals (72% of confirmed cases), with sports horses and cobs representing nearly 40% of infected individuals, whilst median case age was 5 years; critically, only 57% of horses on affected premises were vaccinated, and just 23% of premises quarantined newly arrived animals despite 42% reporting horse arrivals within two weeks of confirmed cases. Professional establishments were disproportionately affected during the initial phase, particularly when infected animals were newly introduced, highlighting the significant biosecurity gaps associated with horse movements and the inadequacy of current preventive measures across GB premises. These findings underscore that without marked improvements in both vaccination coverage and movement-related biosecurity protocols—particularly quarantine procedures and isolation facilities—the GB equine population faces considerable risk from future influenza epidemics, with implications for all professionals advising on herd health management.
Read the full abstract on PubMed
Practical Takeaways
- •Ensure your horses are vaccinated against equine influenza — 72% of cases occurred in unvaccinated animals, making vaccination the single most important preventive measure
- •Implement strict quarantine protocols for new arrivals (at least 2 weeks isolation) and maintain isolation facilities, as new horse movements were implicated in 42% of infected premises
- •Work with your veterinarian to establish biosecurity measures appropriate to your operation size and type, as professional premises and those with better protocols had fewer secondary cases
Key Findings
- •412 confirmed equine influenza cases occurred across 234 infected premises in Great Britain during 2019, with two distinct epidemic phases (January-April and April-August)
- •72% of confirmed cases were unvaccinated and only 18% were vaccinated, indicating low vaccine coverage among affected horses
- •Only 23% of infected premises quarantined new arrivals and 57% of resident horses were vaccinated, demonstrating limited biosecurity and prevention measures
- •New horse arrivals within 2 weeks of confirmed cases were reported by 42% of infected premises, suggesting animal movement as a key transmission risk factor