Equine infectious anemia is a serious disease that affects all species of equine. Identifying infected horses and restricting their contact with susceptible animals is the key to preventing the spread of this disease. EIA is sometimes called "swamp fever".

This disease causes anemia by breaking down blood cells. It is transmitted from infected to susceptible horses by bites from insects, such as deer, stable flies and other bloodsucking horseflies. It also is spread by use of contaminated syringes, needles and tattoo or surgical equipment. Symptomatic stallions can infect healthy mares during breeding. The virus also can cross the placental barrier to cause fetal infection.

The potential to spread EIA is greater during the summer because biting insect populations are higher. Also, horses are used more this time of year, and there the risk is greater of mixing infected horses with susceptible ones.

While there are many ways for EIA to spread, identifying infected horses is easily done by a blood test.

The Coggins test is the most widely accepted diagnostic procedure. ELISA is another approved test. Both determine the presence of antibodies for EIA. The Coggins procedure requires a minimum of 24 hours for completion; ELISA takes much less time.

With the exception of unweaned foals accompanied by their dam, Kentucky requires proof of a negative, USDA-approved EIA test from the previous 12 months in any equine species offered for sale, traded, given away, leased and moved for the purpose of changing ownership. A negative test result also is required for equine being shown or used in activities where horses gather, such as the grounds of a fair or livestock show, public boarding stables, trail rides, racing and the like.

Owners transporting horses within Kentucky should have a copy of the test for each animal as proof of a current, negative test. Before taking horses outside Kentucky, contact the state veterinarian in each state where you will be traveling to make sure you comply with their EIA test regulations.

Horse owners can keep EIA from spreading by following some practical steps.

  • Annually test horses using an approved test.
  • Control biting flies around the stable and other areas where horses are kept.
  • Use disposable hypodermic needles.
  • Always use a new needle and syringe for each horse.
  • Clean and sterilize all instruments by boiling them for 15 minutes before reusing on a different horse.
  • Avoid close horse contact with other equine species of questionable health status.
  • Do not interchange equipment, brushes and bandages between sick animals.

  • For more information on equine health, contact the Lewis County Cooperative Extension Service, or the Office of the Kentucky State Veterinarian.