Katie Hennessy

Horse Owners Need to Know about Equine Infectious Anemia

Also called “swamp fever,” Equine Infectious Anemia is a viral disease that causes a range of clinical signs from no apparent illness to extremely severe, including collapse and death. Positive cases tend to be diagnosed when movement requires a Coggins test to be performed. 

Clinical signs of EIA are non-specific to the disease itself and can be similar to a number of other diseases or illnesses. The more common signs are intermittent fevers, depression, jaundice, anemia, and increased heart and breathing rates. EIA also causes hemorrhage on the mucous membranes and eyes, dependent edema, weight loss, epistaxis (nose bleeds) and bloodwork shows low platelet counts. 

There’s no cure or antiviral treatment for EIA, although supportive nursing care may get a horse through an acute episode. The majority of horses diagnosed with EIA are euthanized due to the severity of the clinical signs or due to non-feasible isolation requirements for the life of the horse. 

Horses diagnosed with EIA are lifelong carriers as there are no successful treatment options available. Horses without clinical signs act as reservoirs for the virus and when bitten by flies can perpetuate the disease among the equine populations. The virus may also be spread through blood and body fluids and tissues. This means equipment must never be shared with a horse known to have EIA and fresh needles and syringes etc should always be used between horses (regardless of EIA status). Mares can also transmit EIA to foals in utero. If a horse has been diagnosed with EIA, it must be kept isolated at least 200 meters from all other Equidae including donkeys for the duration of its life. 

Prevention of EIA is possible through annual testing. A Coggins test should be performed yearly and is required for the movement of horses. All new horses arriving at a facility should show proof of a current negative Coggins test. Fly control is also essential and should include insect repellents and insecticides etc. You should practice proper hygiene and disinfection of any equipment used between horses, particularly dental equipment, and never use needles and syringes more than once. 

This column is sponsored by Polk Equine, and the opinions expressed herein may not reflect those of CFAN or of its advertisers.

BIO: Dr. Katie Hennessy graduated from the University of Illinois College of Veterinary Medicine in 2008 with a degree in large animal health and equine medicine. She completed an advanced internship at The Equine Medical Center of Ocala and is currently the owner and practicing veterinarian at Polk Equine. Her expertise ranges from small and exotic creatures to large animals, specializing in equine medicine.

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