New strain of equine flu responsible for outbreaks, AHT confirms
AHT recommends that all horses are revaccinated if the booster was given more than six months ago.
A new strain of equine influenza is responsible for the recent outbreaks in vaccinated horses, the Animal Health Trust (AHT) has confirmed.
In its latest update, published on Monday (18 February), the trust said there had been 29 outbreaks in 17 counties across England and Scotland.
This heightened number of cases is down the the newly identified Florida Clade 1 H3N8.
Outbreaks in race horses prompted all races to be cancelled across Great Britain for nearly a week earlier this month.
The AHT, which is continuing to test samples, said the current vaccine offers a greater degree of protection that was initially thought when outbreaks began to occur in Europe. This is particularly true when a booster has recently been administered.
Vaccinated horses experience milder symptoms and recover faster than unvaccinated horses. The trust recommends that all horses are revaccinated if the booster was given more than six months ago.
AHT has come up with five protocols to help reduce the number of outbreaks:
- Vaccinate: Horses should receive a booster if they were vaccinated more than six months ago. Unvaccinated horses will need to start a course of vaccinations.
- Isolate: Immediately isolate new or unwell horses from the main yard. Be aware of biosecurity measures.
- Investigate: Speak to organisers about biosecurity measures at any events or equine gatherings before deciding to attend.
- Communicate: Be open about any suspected or confirmed cases to prevent the spread of disease.
- Mitigate: Gather as much information as possible to mitigate the risk of attending an event or moving a horse.
The BSAVA has opened submissions for the BSAVA Clinical Research Abstracts 2026.
