Following the recent death of one horse stabled at Suffolk Downs, in East Boston, Massachusetts, from equine herpesvirus myeloencephalopathy (EHM), no horses are being allowed to leave the track, although no official quarantine has been imposed.

The affected horse died at the Tufts University School of Veterinary Medicine's equine facility, in North Grafton, Massachusetts, after being transferred from the track.

One other horse at Suffolk Downs grounds has developed a fever. Samples drawn from that horse have been sent to the state laboratory for testing and authorities are awaiting the results.

Jennifer Durenberger, DVM, the director of racing for the Massachusetts Gaming Commission, said, the barn the affected horse resided in "is under enhanced biosecurity measures and we are taking other special measures to protect the horse population."

At this time, horses can ship in to Suffolk Downs, but none can leave for any other track or farm. Furthermore, horses stabled in the same barn where the affected horse was housed are being isolated from the general population. Horses from Barn 21 can only train after regular hours when no others are on the track and cannot be entered to race.

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After the case of EHM was diagnosed Lorraine O'Connor, DVM, the chief veterinary health officer for the Massachusetts Department of Agricultural Resources, sent a letter to all horsemen outlining the clinical signs of the contagious disease, which can cause respiratory disease, severe illness, neurologic dis