What Is Coggins In Horses & What Is A Coggins Test?

Last Updated on April 1, 2022

If you are in the horse world, you have heard the term “Coggins“. What exactly is “Coggins”, and what is a Coggins test in horses used for? Despite the frequently incorrectly used term, “Coggins” is not a disease. A Coggins test is a highly specific blood test used for the detection of antibodies to Equine Infectious Anemia, or EIA. EIA is a highly contagious virus that has no cure.

Coggins and Equine Infectious Anemia (EIA)

EIA, also known to some as swamp fever, is a blood-borne infectious disease found worldwide. In the mid-1970s, there were over 10,000 cases of EIA in the United States alone.

EIA spreads rapidly, typically from biting flies or blood-feeding insects. Many horses are not symptomatic until the disease is in its chronic form, with high fever, anemia, swelling, and loss of weight or muscle. EIA frequently results in owners utilizing humane euthanasia.

Coggins and Equine Infectious Anemia (EIA)

A positive horse must remain in quarantine for the remainder of its life, a minimum of 200 yards away from all other horses.

The Dangers of EIA

Once a horse has EIA, it remains permanently infectious to other equines as a lifelong carrier. Unfortunately, there is no vaccine for EIA. Not only is there no vaccine available, but there is no treatment or cure for the disease. Transmission can occur through contaminated blood from one horse to another. Blood-feeding insects such as horse and deer flies can also spread the disease.

Coggins Test

So, what exactly is a Coggins test for horses? A Coggins test checks for EIA antibodies through blood samples sent to a state-approved lab. Although it’s a simple blood draw, the actual paperwork will reflect vital information for your horse’s identification, including age, color, breed, and markings or scars on each side. This identification method helps prevent fraudulent tests.

A Coggins test is typically good for one year, but some states only honor the test for 6 months. Coggins tests are so important, each state has its own testing requirements and legal mandates. Many require an up-to-date Coggins for travel within or into their state, along with a health certificate. A health certificate is different from a negative Coggins test, but owners frequently opt for both at the same time.

Because of the Coggins test and human effort, EIA has nearly been eradicated in many areas. Positive EIA cases drastically decreased over the last thirty years, despite spikes seen in some areas of the United States in 2018 and 2019.

In most areas, state law requires a recent Coggins for sales of any horses. Events and host facilities such as rodeos and horse shows will also require proof of negative Coggins before allowing horses to enter the premises.

Things to Remember

Because there is no vaccine or cure for EIA, it is important to understand what a Coggins test is and keep your horse up to date. Veterinarians typically recommend horses have a Coggins test performed annually.

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How do you prevent equine infectious anemia in horses?

Preventing equine infectious anemia in horses involves a multi-pronged approach. When possible, prevent exposure to biting insects that may carry EIA by active management of the environmental conditions and insect control. A number of different insecticides are available to protect horses from biting insects, including the insecticide permethrin, which is commonly used in the US for this purpose. Since the disease can be transmitted via contaminated needles, always use disposables needles and syringes when administering vaccines and medication to horses. You should also always sterilize any dental tools before using them on another horse. Horses should be tested for EIA at least annually. You should also test any new horse you are about to bring home at the time of purchase examination.

Why is it called a Coggins test?

The Coggins test is named after Leroy Coggins, the veterinarian who invented it in 1970 to detect antibodies against equine infectious anemia virus (EIA). He came up with the idea of using the red cells in blood to detect antibodies against EIA.  
Coggins test is also known as Red Blood Cell Agglutination Test. It is a blood test that can be used to determine the presence or absence of EIA in a horse. This test is mainly used in breeding horses to check for the presence of EIA. There are other approved tests to determine if a horse is infected with EIA, but the Coggins test remains the most widely used test for EIA.

What happens if a horse tests positive for Coggins?

There is no cure for equine infectious anemia (EIA) and once infected with EIA, a horse remains infected for life. Infected horses are posing a risk to other horses so any infected horse must be immediately isolated from them. To prevent further transmission of EIA and to help control the spread of EIA in your horse population, you need to isolate and quarantine any confirmed cases of EIA in a space that is at least 200 yards away from the healthy individuals. The horse should receive regular veterinary care and must be monitored for any symptoms of EIA or any other diseases. 

How do horses get equine infectious anemia?

Equine infectious anemia is a fatal viral disease of horses caused by an equine retrovirus. Infected horses develop symptoms of fever, weight loss, muscle pain, and weakness. The disease can progress to hemorrhage, shock, coma, and death. The virus is spread by biting flies, such as deer flies and horseflies, and is transmitted through direct contact with infected horses or their blood, fluids, or tissues. The virus also can be transmitted through contaminated needles and syringes during medical procedures, or through blood transfusions. The disease is usually diagnosed by a veterinarian, and it can be confirmed using a Coggins test.

What are the symptoms of equine infectious anemia?

The most common symptom of EIA (equine infectious anemia) is fever, which is usually accompanied by other symptoms such as anorexia, depression, swelling of the underside of the belly and legs, muscle weakness and wasting, jaundice of the mucous membranes and infertility. Horse owners should consult their veterinarian about equine infectious anemia before bringing home a new horse. This disease can make a horse vulnerable to other diseases that can cause death or serious illness.