UK study links equine influenza risk to autumn trade patterns
CURRENT BRIEF VERSION: A new UK surveillance study suggests equine influenza risk didn’t simply fade after the country’s 2019 epidemic. Reviewing confirmed outbreaks from 2020 through 2024, researchers found a clear late-year pattern, with 52% of outbreaks occurring from October through December. They also found that more than 75% of affected premises had received a new horse arrival within the previous two weeks, and among index cases with a recorded origin, 56% came from Ireland. The study, published in Equine Veterinary Journal, links that seasonal spike partly to horse movement, especially trade in non-pure-bred horses, rather than to year-round local persistence alone. A separate Equine Veterinary Journal genomic surveillance study on strangles adds a useful parallel: among 511 UK Streptococcus equi isolates collected from 2015 to 2022, researchers found rapid shifts in circulating strain groups and evidence of transmission between horses in different UK regions, pointing again to active movement-linked spread rather than long-term silent persistence alone. (pubmed.ncbi.nlm.nih.gov)
Why it matters: For equine veterinarians, the findings sharpen the picture of when and where risk concentrates. The authors say vaccination, quarantine, and biosecurity around new arrivals should be a priority, particularly in the fourth quarter and around sales, transport, and other high-throughput movement hubs. The strangles paper reinforces the same operational lesson: recent infections and short-term carriers may be more important in ongoing spread than long-term carriers alone, and sequence-based surveillance could help identify cross-regional transmission earlier. That aligns with the UK Equine Infectious Disease Surveillance team’s broader role in advising practices on outbreak control, sampling, vaccination, and biosecurity, and with international guidance that equine influenza vaccination should include both Florida clade 1 and clade 2 strains. (equinesurveillance.org)
What to watch: Watch for whether UK surveillance and industry guidance translate these findings into more targeted pre-movement vaccination checks, post-arrival quarantine recommendations, tighter biosecurity around autumn and winter horse trade routes, and broader use of genomic surveillance to track movement-driven spread across regions. (pubmed.ncbi.nlm.nih.gov)