Racing continues at Parx Racing despite the EHV-1 outbreak. Photo by Barbara Weidl/Equi-Photo
The equine herpes virus (EHV-1) has claimed the lives of four horses at Parx Racing in Pennsylvania.
If no additional horses test positive, the track will remain quarantined until May 5. No horses can ship in or out during this time. Racing continues, although horses from two barns are not allowed to participate due to being in isolation.
Since the beginning of the month, four horses from Parx tested positive for EHV-1. The horses died or were euthanized due to the severity of the disease.
EHV-1 can cause four manifestations of disease in horses, including a neurological form, respiratory disease, abortion and neonatal death.
Almost all horses have been infected with the virus and have no serious side effects. Experts say it is unknown what causes some horses to develop the serious neurological form that can be fatal.
April 22 Update: A sixth horse has tested positive for EHV-1 at the track. The quarantine remains in place.