Management and environmental factors involved in equine influenza outbreaks in Ireland 2007-2010.
Authors: Gildea S, Arkins S, Cullinane A
Journal: Equine veterinary journal
Summary
# Editorial Summary: Equine Influenza Management in Endemic Populations Between 2007 and 2010, Irish researchers documented 28 equine influenza outbreaks across 13 counties, analysing 404 horses on 16 premises to identify which management and environmental factors increased disease risk in a vaccinated population. Despite widespread vaccination coverage, EI continued to cause significant economic losses, with veterinary advice typically sought more than five days after clinical signs appeared—a critical delay that likely facilitated viral spread. Key risk factors included recent horse movements (identified in 15 premises), inadequate housing separation (single air spaces), use of teaser stallions, and contamination via fomites and personnel; vaccination effectiveness was compromised by inconsistent booster protocols and suboptimal timing of previous doses. Premises that promptly isolated suspected cases, confirmed diagnosis via RT-PCR, implemented strict biosecurity, and administered cohort boosters achieved measurably better outbreak control than those employing ad-hoc measures. For practitioners, this research underscores that outbreak prevention in endemic regions demands rigorous vaccination discipline (6-monthly boosters, documented serological response), strategic quarantine of new arrivals with serological verification, and meticulous boundary management between yards—particularly critical for competition yards, breeding establishments, and livery facilities where horse movement and shared personnel are routine.
Read the full abstract on PubMed
Practical Takeaways
- •Recognize that EI can spread despite vaccination; implement strict biosecurity measures including isolation, booster vaccinations every 6 months, and maintaining separate air spaces between stables
- •Move quickly to diagnose suspected EI cases using RT-PCR and isolate affected horses within 5 days of clinical signs to prevent spread through personnel, equipment, and fomites
- •Screen and vaccinate all new horse arrivals before introduction to premises, and maintain detailed vaccination records to track booster timing for each individual horse
Key Findings
- •28 premises in 13 Irish counties diagnosed with EI outbreaks between June 2007 and January 2010, with veterinary advice sought on average >5 days after first clinical signs
- •Horse movement was identified as the primary outbreak trigger in 15 of 16 premises studied, with housing type, teaser stallions, and fomites/personnel contributing to virus spread
- •Vaccination status, years of vaccination history, time since last vaccination, and age significantly influenced disease expression in affected horses
- •Isolation combined with vaccination and RT-PCR rapid diagnosis were effective control measures when implemented on premises