A Phoenix racetrack’s horses remained under quarantine Friday as officials worked to get the upper hand on an equine herpes outbreak that has infected more than a dozen horses in New Mexico.
One horse had to be euthanized this week at Turf Paradise in north Phoenix, manager Vincent Francia said. The horse was one of three that arrived Jan. 20 from Sunland Park, New Mexico.
The other two are under isolation for 21 days. So far, they show no signs of the virus.
When the facility first learned horses in Sunland Park were testing positive for the virus, the three horses were tested. Francia said a nasal swab came back negative for all three and the animals seemed fine. Then one, a mare, was suddenly unable to stand Wednesday. She eventually had to be put down.
Read more: NBC News