Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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Equine Infectious Anemia: An Incurable Disease


Pet Column for the week of September 3, 2001


Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
Jennifer Stone
Information Specialist

Equine Infectious Anemia is caused by a virus that attacks the immune system and ruptures blood cells, resulting in severe anemia. This virus is similar to HIV, the one that causes Aquired Immune Deficiency Syndrome (AIDS) in humans. Like HIV, the EIA virus mutates frequently, making the creation of a vaccine against it very difficult.

Dr. Dean Scoggins, an equine Extension veterinarian at the University of Illinois College of Veterinary Medicine in Urbana, says, "The reason that this virus is so devastating is that there is neither a vaccine nor an effective treatment available for it."

A horse can start showing symptoms of the disease 1 week to 1 month after exposure to the virus. Early symptoms of this disease include fatigue, and some horses may stop eating. A high fever of 104-106 degrees Fahrenheit can accompany the infection, and small hemorrhages often appear in the mucous membranes of the mouth and base of the tongue.

Although it is seldom fatal, the disease causes the horse to be weak and susceptible to infections. Some infected horses do not display any symptoms of the disease at all, but carry the virus in their blood. These carriers may begin to show symptoms of the disease only if they become stressed. The disease is spread to other horses by biting insects, particularly horse flies. Until the policy of using disposable needles was adopted several years ago, another major means of transmitting the disease was through the reuse of needles during routine vaccinations.

The only available means of controlling the disease is to isolate it and attempt to eliminate it from the area. For this reason, if a horse is found to have the virus, it is usually euthanized to prevent the spread of the disease. If the owner wants to keep the infected horse alive, then it must be isolated from other horses and kept in a facility equipped with special insect-proof screening in order to prevent the spread of the disease.

Dr. Scoggins says, "This means that an infected horse can be turned out to pasture only in the winter, when there are no biting insects around."

The Coggins test is a blood test to determine the presence of the disease in an infected horse. In order for a horse to participate in advertised events such as rodeos, sales, or shows, it must receive a negative Coggins test prior to the event. A negative test is also required for a horse to change ownership. If you are planning to purchase a horse and the Coggins test is older than 4 to 6 months, then you should repeat the test before purchasing the horse.

Dr. Scoggins says, "Never purchase a horse without proof of a current negative Coggins test!" If you need to have a Coggins test run on a horse, the blood must be drawn by a licensed veterinarian, and the blood must be sent to a state laboratory for testing.

These rules and regulations seem strict, but in the long run they will help to eradicate this devastating disease from the horse population of Illinois. If you have any questions regarding Equine Infectious Anemia, contact your local equine veterinarian.