Flu confirmed in horses vaccinated this spring and broodmare: foal also showing signs

Two horses vaccinated against equine flu during the past three months have been confirmed as having the virus, in five outbreaks confirmed in the first few days of this month.

As of yesterday (3 July), flu has been confirmed in County Durham, Monmouthshire, Norfolk, Leicestershire and East Sussex. Among the affected animals is a broodmare whose three-month-old foal is also showing clinical signs of the condition.

The Leicestershire outbreak involves two horses, one of whom was vaccinated in March and the other in April. The diagnoses were made as they were required to be swabbed for flu to be allowed entry to a competition.

The same process confirmed the East Sussex case, a horse who was also vaccinated.

“Where infection has been confirmed in vaccinated animals, the appropriate vaccine manufacturers and the Veterinary Medicines Directorate will be made aware by the treating vet,” the Animal Health Trust (AHT) said in a statement.

“If a vet has a suspect case of equine flu in a vaccinated animal, we encourage sampling to confirm infection, but suspect cases on yards with confirmed cases should also be reported to vaccine manufacturers.”

The Monmouthshire outbreak was confirmed on a yard where 10 unvaccinated horses live. The one diagnosed case is a mare with a three-month-old foal, who is also “demonstrating clinical signs”. All the other horses on the yard have also since developed symptoms, the AHT said, and it is likely the virus was transmitted by recent attendance at an event.

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The case confirmed in Norfolk is a horse who was vaccinated a year ago, at a yard from which horses have gone off-site in the past fortnight, while the four confirmed in County Durham are unvaccinated. It is reported that “multiple” other horses on the same yard are also affected.

The AHT believes the recent resurgence in the flu outbreak – 41 outbreaks were confirmed in June, more than any other month this year – has been caused by increased movement and mixing of horses at events. Its advice to owners is to be vigilant, and to consider six-month booster vaccinations.

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