Many horse owners have heard of a Coggins test, but some do not know what the test evaluates and why it is so important for the horse industry. A Coggins test is a blood test used to identify the presence of antibodies for equine infectious anemia, a potentially fatal disease with no current treatment available. There are multiple tests to detect if a horse has EIA antibodies, but the Coggins test is the most popular and well known among horse industry professionals.

What is Equine Infectious Anemia?

Equine infectious anemia is a bloodborne viral disease that can affect all equids. This virus is of great concern for the horse industry and there is currently no treatment or vaccine for it. Horses with EIA have varying symptoms and prognoses. Acute symptoms often include a fever, disorientation, and weight loss. Rapid death has also been reported for some horses with EIA. Most often, horses with EIA are asymptomatic carriers—showing no signs or symptoms—which is one of the reasons testing is so important. Horses positive for EIA are lifelong carriers and pose a risk to any other horse they may be around. Therefore, EIA carriers must either be permanently quarantined and kept at least 200 yards away from other horses or euthanized.

Transmission of EIA

EIA is most often transmitted by biting flies; tabanids (horse and deer flies) are considered the most significant transmitters. Biting flies transmit EIA by taking a blood meal from an EIA carrier and then transmitting that infected blood to a non infected horse. Since it is relatively impossible to eliminate blood-sucking insects around horses, there is always the potential of a horse contracting EIA (and other bloodborne diseases) when in the vicinity of an infected horse. Other modes of transmission of EIA include the use of contaminated equipment, such as used needles and syringes; mare-to-foal transmission in utero; and through natural breeding of mares and stallions.

Reducing the Spread of Equine Infectious Anemia

Obtaining a negative Coggins test ensures that the horse does not have the antibody for EIA at the time of testing. However, you are encouraged to continue implementing biosecurity measures in addition to the annual test. Since EIA is primarily transmitted by flies, employing fly management strategies can help reduce the likelihood of infection. Horse owners are encouraged to use an integrated pest management (IPM) system, which uses multiple, targeted strategies to reduce fly populations.

Prioritizing horse health and sanitation can also help reduce spread. Always use a sterile needle when giving your horse an injection. If using a multidose vaccine bottle, use a sterile needle every time you puncture the bottle. Require proof of a negative Coggins test for horses coming onto your farm and/or interacting with your horse. Quarantine new horses entering the premises for at least 14 days after arrival, evaluating them for signs of illness during that time. Require proof of a negative Coggins test for horses you are considering buying or breeding. The American Association of Equine Practitioners also recommends that horse owners only participate in shows that require a negative Coggins test.

It is always recommended that horse owners regularly evaluate their horses for signs of illness. If you suspect your horse has contracted EIA or any other virus, separate them from other horses to reduce the chances of transmission and contact us immediately.