Equine Infectious Anemia (Swamp Fever)

Equine Infectious Anemia is a viral disease for which there is no known cure or vaccination. Learn more about the disease and the Coggins Test, used to identify horses that have been infected with the disease.

If you’re like me, you hold your breath with apprehension when your vet does your horse’s annual Coggins Test for Equine Infectious Anemia, and only let it out again when you get the negative results back a week or two later.

Equine Infectious Anemia (EIA), also known as Swamp Fever, is a viral disease for which there is no known cure or vaccination. I always thought that it was spread by the bite of diseased mosquitoes, but recently discovered that research has determined that the horsefly is the vector. If a horsefly bites an infected horse and then bites a healthy horse, the disease will get passed on from one horse to the other.

Horses affected with acute EIA will show symptoms of fever, depression and loss of appetite. About thirty percent of horses infected with acute EIA will die within a month. Horses which recover from the acute form of EIA will often suffer frequent recurrences, accompanied by weight loss and anemia. In addition, some horses can be infected but be completely asymptomatic, showing no sign of the disease at all.

Because chronic sufferers and asymptomatic carriers can appear completely healthy, the Coggins Test was developed in the 1970’s to determine whether a horse is carrying the disease. To perform a Coggins Test, your vet will draw a sample of blood which he will then send into an approved testing facility where the blood will be tested for EIA antibodies.

If your horse tests negative on the Coggins Test, you’ll be presented with a certificate which identifies the horse and its negative status. This certificate can be presented to barn owners, as proof of the negative status, and many, if not most, barns will only accept horses with this proof. Show organizers also require proof of a negative Coggins and you’ll also usually need a negative Coggins in order to transport your horse from one state to another.

However, depending on state regulations, horses which test positive for EIA, must be immediately quarantined, along with other horses on the same property, a prescribed safe distance from other negative horses in surrounding properties. In many cases, positive horses must be branded for identification. If a suitable quarantine cannot be maintained, the horse(s) must be moved to an approved equine research facility, or must be destroyed.

F.R.I.E.N.D.S, the Florida Research Institute for Nurturing, Development and Safety, operates a ranch on the eastern edge of the Everglades, in Florida, which provides an alternative for horses testing positive for EIA. Since 1987 they have taken in EIA positive horses and maintained them in a safe and humane facitily, at the same time providing researchers an opportunity to search for a vaccine or cure.




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