The UK racing industry is at a standstill after an outbreak of equine influenza forced the suspension of all racing activity.

On Wednesday, the British Horseracing Authority (BHA) announced that racing would be shut down at all British racecourses on Thursday. The decision was made after the Animal Health Trust identified three confirmed cases of equine influenza among vaccinated horses at an active racing yard.

Horses from the infected yard raced Wednesday at the Ayr and Ludlow courses, potentially exposing “a significant number” of horses across the UK and Ireland. The BHA said it was communicating with yards whose horses may have been exposed to the virus but admitted that “the full extent of potential exposure is unknown.”

On Thursday, the BHA announced that racing would not resume in Britain until next Wednesday (13) “at the earliest.” The BHA said a decision on whether to allow racing to continue on Wednesday would be made on Monday (11) following “further scientific advice and discussions with participants.”