Why do I need a Coggins test for my horse?

Many times routine yearly procedures like vaccinations, dental exams, and blood tests, are done automatically. It’s just something that is done and done every year, but why? Yearly vaccinations are important to help keep the horse healthy and prevent disease. Dental exams are necessary because horse’s teeth are constantly growing and often need to be floated. What about this Coggins blood test? Why do you need to have it done?

The Coggins test was developed by Dr. Leroy Coggins in the early 1970’s. This particular test was the first of its kind to identify carrier animals (animals that are not overtly sick, but are carrying the virus in their blood) for Equine Infectious Anemia (EIA). The Coggins test is internationally recognized as the standard to which all other tests for EIA are compared. Many states within the US require that horses have a negative Coggins test before they travel to the state.

The Coggins test is able to identify horses infected with EIA virus. EIA is an infectious and potentially fatal viral disease of horses. Unfortunately, no vaccine or treatment exists for this disease. EIA can cause fever, weight loss, a decrease in red blood cells, swelling of the limbs and weakness. EIA is transmitted by deer and horseflies. The U.S. had a “hot zone” of EIA infected horses up until the mid -1990’s. An area, including Minnesota spanning south to Texas and east to Virginia, was where 92% of infected horses were located. The risk of EIA was highest in this region because in part of favorable environmental conditions. In the 2015, test positive horses have been identified outside of the “hot zone” in Utah, Washington, New York, Oklahoma, Oregon and New Mexico.

Coggins tests are performed because many states in the US require the test prior to entrance to the state. Since Coggins tests identify horses infected with EIA, and EIA is an infectious and potentially fatal virus that has no treatment nor prevention, USDA deemed the best practice to prevent spread of the disease is yearly testing.

Dr. Heather Hilbrands, DVM, grew up in Milbank, S.D., and received an animal sciene degree from South Dakota State University. She graduated from veterinary school at Iowa State University in 2006. She practiced large and small animal veterinary medicine in South Dakota prior to coming to North Dakota. She now practices at Casselton Veterinary Service, Inc. in Casselton, N.D.