Equine infectious anemia found in horse

A pony recently obtained by an equine rescue group from a sale barn in Pennsylvania and brought to a stable on a New Jersey premises has been confirmed positive for Equine Infectious Anemia (EIA). Officials in Pennsylvania are investigating the source of the infection. The pony has been euthanized.

Equine Infectious Anemia (EIA), also known as swamp fever, is an infectious, viral disease that infects all equidae (horses, donkeys, zebras, etc.) It is not infectious to humans. There is no effective treatment or approved vaccine available for Equine Infectious Anemia.

The disease is spread via blood-to-blood transmission, not close proximity or casual contact. EIA is usually transmitted from horse to horse by large biting insects such as horseflies and deerflies. The bites from these flies stimulate defensive movement by the horse, which often results in an interruption of the flies' blood feeding. When interrupted, flies are motivated to complete feeding as soon as possible.

They then attack the same or a second host and feed to complete their meal. Any infective material from the blood of the first host that is present on the mouthparts of the flies can be transmitted to the second host. Blood transfusions, unsterilized or contaminated needles and equipment contaminated with blood from an infected horse can also spread the virus.

Depending on an individual horse's immune system and the severity of its reaction, clinical signs of EIA can range dramatically. While some infected with EIA show no signs of illness, others display fever, weight loss, icterus (yellowing of body tissues), anemia, swelling of the limbs, weakness, rejection of feed, and/or sudden death.

To minimize disease transmission, all equidae should be tested for EIA before being brought onto a new premises. The animal should be isolated and observed for 45 to 60 days, then retested before being introduced to the herd.

New Jersey law requires all imported equidae to have a negative official test for EIA within the past 12 months. All equidae traveling on New Jersey roads must have a negative EIA test a maximum of 24 months prior to such travel, and any equidae that change ownership must be tested a maximum of 90 days prior to such a change in ownership. Equidae younger than six months and accompanied by a dam (female parent) that has a negative official test within the past 12 months are exempt from EIA testing.

For further information about EIA or information about EIA testing performed at the NJDA-Division of Animal Health Diagnostic Laboratory, please contact Dr. Nancy Halpern at 609-292-3965 or via email at Nancy.Halpern@ag.state.nj.us.