STICKNEY, Ill. – An outbreak of equine herpesvirus at Hawthorne Race Course that has left two horses dead remained confined to a single barn as of Thursday morning, a hopeful sign that the virus has not spread into the general population at the track.Illinois state veterinarian Dr. Dawn Folker-Calderon said since Wednesday there had been one potentially new herpesvirus (EHV-1) case in the infected barn, Barn A. But no cases outside that barn had yet been reported, meaning the situation at Hawthorne is basically unchanged since Wednesday, when the Illinois Department of Agriculture confirmed that the track could continue running its race meet as long as no cases outside Barn A were reported.The first two horses to contract EHV-1, which morphs from a typical-seeming upper-respiratory infection into a serious neurological sickness, both died from the virus (the first horse was euthanized), but three other horses who tested positive for EHV-1 remained in stable condition Thursday, Folker-Calderon said. Folker-Calderon was focusing Thursday on testing all horses in Barn A for EHV-1 as well as any other horse on the Hawthorne backstretch who was reported to have run a fever. Folker-Calderon said she was relying on private-practice vets and trainers to alert her if any horse got sick.“I would hope people understand the seriousness of this,” she said.Barn A remains isolated, and the approximately 70 horses stabled there cannot leave until all test negative for EHV-1. While scratches abounded on Hawthorne’s card Wednesday, scratches – outside of races taken off the turf – fell in a normal range Thursday.