Testing keeps equine infectious anemia at bay


Between many required vaccinations and routine checkups, horse owners have likely heard of the Coggins Test for Equine Infectious Anemia (EIA), but may not be aware of what exactly this test entails.

EIA is a disease brought on by a virus which is often transmitted by horse flies and horses who test positive for it are required to be separated from all other horses for the rest of their lives. Approximately two decades ago, Texas regulations to prevent this disease were tightened and have led to the near eradication of EIA, however there are still cases every year.

There are multiple places at Texas A&M which offer testing for disease, including the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) and departments within the Large Animal Hospital.



The disease can have critical effects on horses and is spread by some insects, according to Guy Sheppard, Doctor of Veterinary Medicine and Veterinary Diagnostician at the TVMDL.

“It causes anemia and or a depletion or destruction of red blood cells in horses that are clinically infected,” Sheppard said. “It is mainly transmitted by the transmission of the organism in blood cells. The main vector are blood sucking insects, and the insect that can hold the most blood is the horse fly. They can transmit the most blood so the horse fly is the main vector involved in the transition of EIA.”

Symptoms can last from seven to 30 days after contact with the virus but a horse can still test negative for EIA up to 42 days because their immune system has not produced detectable antibodies, according to Michelle Coleman, assistant professor in the department of Large Animal Clinical Sciences.

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