Two horses in New Jersey have tested positive for equine piroplasmosis. The animals were among four purchased in 2008 from a ranch in South Texas on which 288 horses have now tested positive for the tick-borne disease.

"Additional testing on the imported horses and contact horses is under way," noted a statement from the New Jersey Department of Agriculture. "Quarantines have been placed on the affected premises and precautions implemented to prevent the spread of this disease to other horses."

New Jersey Secretary of Agriculture Douglas H. Fisher asked horse owners and veterinarians to be vigilant for signs of equine piroplasmosis, which can include a host of nonspecific clinical signs, such as fever or anemia. But some infected horses might appear well. Blood tests are needed to diagnosis the disease.

A Nov. 6 report by John Clifford, DVM, deputy administrator of the USDA's Animal and Plant Health Inspection Service, gave more details on the ongoing Texas investigation. As of Nov. 4 the National Veterinary Services Laboratory had confirmed the disease in 288 horses on the property. Investigators were continuing to test horses there as well as epidemiologically linked animals