The British Horseracing Authority has confirmed an outbreak of Equine Herpes Virus (EHV) at the yard of Grand National-winning trainer Dr Richard Newland in Worcestershire.
Movement restrictions have been placed on the yard to limit any future spread while further sampling is under way to determine the exact strain, which has yet to be confirmed but is thought to be EHV-1.
As of yet the BHA is not aware of any confirmed cases in any other yards but trainers and vets have been asked to be vigilant to clinical signs of EHV and advise twice daily temperature checks for all horses.
While there is a low risk of transmission in a bio-secure raceday environment, there is a slight chance the horses were infectious before showing symptoms so trainers with runners at Uttoxeter, Worcester and Southwell on June 2, 4 and 6 respectively have been asked to be especially alert to signs of the disease.
The most common strain of EHV is EHV-1 which causes respiratory disease, abortion in pregnant mares and neurological disease in horses of all ages and types. EHV-4 is also common which usually only causes low-grade respiratory disease but can occasionally cause abortion.
Once horses have been infected they can carry it silently and it can reactivate later in life.