The total number of horses which have tested positive for equine infectious anemia (EIA) in northeastern Pennsylvania has risen to 23. Twenty-two of the horses have been destroyed, and three remain under quarantine. Another horse tested positive in Lebanon County, but the Pennsylvania Department of Agriculture (PDA) has been unable to link that horse with the positive reservoir group. Two other cases of EIA were detected earlier in 1999 in the state. The first cases in the current positive group were detected at an auction on Sept. 18. EIA, an incurable viral disease, can be detected by a blood test known as a Coggins test. Often compared to HIV or AIDS in humans, EIA is spread through contaminated blood via biting flies, and through improper use of equipment and needles.

The management of the auction in the northeast corner of Pennsylvania, where the positive horses were discovered, decided to give the additional service of Coggins tests through a private practicing veterinarian. Blood samples were taken the Saturday of the sale, and results were returned the following week after the horses were dispersed. Two of the 100-plus horses at the auction tested positive, but showed no clinical signs of EIA.

According to Bruce Schmucker, VMD, a veterinarian at PDA, the night of the auction was relatively “chilly” and insect-free, which reduced the risk of disease transmission. Fortunately, all horses exposed at the sale were located and tested negative except for one horse, which officials say has “vanished.”

The two horses which were test-positive at the auction site were traced to two Wayne County camp herds. Ten of 20 horses were positive in one herd, while two of 65 horses were positive in the other herd. Both farms were quarantined for 45 days after the 14 positive horses were euthanized. In terms of incubation of the disease, an exposed horse is expected to test positive within 20 days if it contracts the disease. Some horses might take longer to seroconvert—25 to 28 days. “That is why we wait 45 days. It is highly unlikely that horses will turn sero-positive after 45 days,” assures Schmucker. All of the suspect horses in Wayne County have been released from quarantine