A horse trained by Ron Dandy at Parx Racing tested positive for the equineherpesvirus on Tuesday, which will extend the quarantine the track has been under since April 1. The sick horse is the sixth to test positive for the herpesvirus at Parx. The first four horses to contract the disease either died or were euthanized due to the severity of their condition. The fifth horse, Sunshine Wild, who Butch Reid claimed from Dandy on March 29 - the day before the first horse to de diagnosed with the herpesvirus became ill - has been sent to an off-site isolation area and is showing signs of improvement, according to Sam Elliott, the director of racing at Parx. Barn 30, where Dandy and trainer Michael Aro are stabled, has been quarantined since April 1. Their horses have not been able to train or race since the quarantine began. Dandy and Aro each trained two of the first four horses to test positive for the virus. Barn 4, where Reid and trainer Keith Nations are stabled, is also under quarantine because Sunshine Wild was housed there. Because of the severity of the situation, the Pennsylvania Department of Agriculture has put new protocols into place at Parx. Elliott is in the process of obtaining the materials needed to construct an isolation area on the Parx backstretch, where horses who test positive for the virus will be relocated. The isolation area will consist of temporary stalls under a tent or tents. On May 10 - which will be 21 days after the sixth horse tested positive - all of the horses in Barns 4 and 30 will be tested for the herpesvirus. If any horses test positive, the quarantine clock will reset and they will all be retested again three weeks later. During the quarantine, horses stabled at Parx are not allowed to leave the grounds. Horses are not being allowed to enter the stable area, as the backstretch is at capacity. Racing has continued uninterrupted at Parx during the quarantine.