A restriction on horses shipping into Philadelphia Park from Penn National due to three horses testing positive for equine herpesvirus type 1 (EHV-1) at Penn may be lifted early next week, officials for both Pennsylvania racetracks said Wednesday. "Although three horses from trainer Bob Wolfe did test positive, we had some good news recently," said Richard Schnaars, general manager of Penn National. "We sent blood samples (all from Wolfe's stable) to the Gluck research center in Kentucky and, other than those three horses, the rest came back negative."Two of the three horses testing positive for EHV-1 had been put down; the third had spiked a fever but has not shown any neurological symptoms. Schnaars added it's unclear how the EHV came to Penn National, but that Wolfe had been providing information about the infected horses to veterinarians and the Pennsylvania Department of Agriculture.The EHV-1 organism can cause three different forms of disease, including rhinopneumonitis (a respiratory disease often affecting young horses), abortions in pregnant mares, and neurologic disease. Neurologic symptoms were associated with the Penn National horses. There are at least seven other strains of equine herpesviruses, named in order of their discovery. (visit http://www.TheHorse.com/news.asp?fid=32 for more on herpesviruses.) Horses can survive the neurologic form of EHV-1 with supportive care, but if a horse becomes recumbent, it is difficult to nurse the horse back to health.Swabs taken from horses stabled in Wolfe's barn, but belonging to different trainers, have also been sent to the Department of Agriculture for testing, Schnaars said.Sal Sinatra, director of racing for Philadelphia Park, said that the shipping restriction between the two tracks could be lifted Monday."The loss of Penn shippers the last week hasn't really affected our field sizes," said Sinatra. "I'd like to see the ban lifted in order to allow some Penn National trainers who had been participating in our starter handicap series to be able to come back."