What is a Coggins test?

A Coggins test – more accurately referred to as an enzyme-linked immunosorbent assay (ELISA) – is a blood test that screens for a potentially fatal disease called Equine Infectious Anemia (EIA).

This disease, which sometimes goes by the handle “swamp fever,” is caused by a virus that affects the immune system of horses, donkeys, mules and other members of the Equidae family. There is no vaccine or cure for EIA.

In its acute form, EIA is characterized by a sudden onset of symptoms that include high fever, anemia (due to the breakdown of red blood cells), weakness, swelling of the lower abdomen and legs and irregular heartbeat. In some cases, sudden death occurs. EIA may also cause abortion in pregnant mares.

How does EIA spread?

EIA is spread by biting flies (such as horse flies, deer flies and even stable flies) and mosquitoes that first bite an infected horse and then bite another horse that’s nearby. This disease is extremely serious and outbreaks can have catastrophic consequences.

Preventing transmission

That’s why it’s crucial to detect potentially infected travelling and showing horses through regular testing. Most horses infected with EIA do not demonstrate any symptoms whatsoever. Unfortunately, once infected, the animal becomes a carrier of the virus for life. A horse that tests positive for EIA must either be euthanized or quarantined behind screen mesh for the rest of its life.

Import and export restrictions

In both Canada and the United States, a “negative Coggins” is required for import or export of horses across their international borders. As well, many U.S. states require a negative Coggins test for interstate travel. Further, a negative Coggins is necessary in both countries for your horse to gain entry to racetracks and the majority of competitive events. An up-to-date Coggins test is recommended any time horses are gathered together, whether in a boarding stable or for competition or recreation.

How is a Coggins test performed?

To begin, we assess the horse to ensure it is not exhibiting symptoms of EIA. As part of the physical exam, we fill out an EIA test form, which requires information such as the horse’s age, breed and descriptions of colour markings and scars.

Most horses that test positive for EIA antibodies do not show any outward sign of sickness or disease. For this reason, the Coggins test includes the requirement for a blood sample to be taken and submitted to an accredited lab for analysis. The blood sample must be drawn by a Canadian Food Inspection Agency (CFIA)-accredited veterinarian. Dr. Allossery has this accreditation.

How long is a negative Coggins test good for?

For export purposes, the test is good for just 180 days (approximately 6 months). You can find more information regarding EIA and import/export restrictions at the Canadian Food Inspection Agency (CFIA) website.


Allossery Equine Veterinary Services
11499 York Durham Line
Mount Albert, Ontario
L0G 1M0

(289) 338-2068