EIA exposure in Wyoming horses

Wyoming animal health officials have placed additional facilities under quarantine after determining that horses residing there were exposed to a horse that ultimately tested positive for equine infectious anemia (EIA), the Equine Disease Communication Center (EDCC) reported Sept. 1.

“The Wyoming Livestock Board has quarantined an additional seven premises, totaling nine now, as a result of equine being exposed to a horse originating in Colorado which was found to be positive for equine infectious anemia,” the EDCC said. “Counties include Sweetwater, Lincoln, Teton, Park, and Fremont.”

The EDCC said 41 horses were exposed at a Sweetwater County premises where the index case was sent illegally from Colorado.

“The remaining horses were exposed to the same horse in Colorado prior to being shipped to Wyoming,” the EDCC said. “All but two of these exposed horses were imported illegally to Wyoming, as well. An additional four horses and three premises are still being traced in Natrona and Laramie counties.”

In a statement on the EDCC’s website the Wyoming Livestock Board said it “would like to remind horse and other livestock owners that the consignor, the consignee, and the shipper of livestock are each individually and equally responsible for making sure that the Wyoming Livestock Board’s import requirements have been met.”

Information on health requirements that must be met when shipping livestock interstate is available at interstatelivestock.com, the Livestock Board said.

“For brand requirements, the state brand agency should be contacted directly,” the Livestock Board said in its EDCC statement. “In Wyoming brand inspections are required at change of ownership and to move all horses, sheep, and cattle from county to county and when leaving the state.”

EIA 101

Equine infectious anemia is a viral disease that attacks horses’ immune systems. The virus is transmitted through the exchange of body fluids from an infected to a noninfected animal, often by blood-feeding insects such as horseflies. It can also be transmitted through the use of blood-contaminated instruments or needles.

A Coggins test screens horses’ blood for antibodies that are indicative of the presence of EIA. Most U.S. states require horses to have proof of a negative Coggins test in order to travel.

Once an animal is infected with EIA, it is infected for life and can be a reservoir for the spread of disease. Not all horses show signs of disease, but those that do can exhibit:

  • Progressive condition loss;
  • Muscle weakness;
  • Poor stamina;
  • Fever;
  • Depression; and
  • Anemia.

There is no vaccine and no cure. A horse diagnosed with EIA dies, is euthanized, or must be placed under extremely strict quarantine conditions (at least 200 yards away from unaffected equids) for the rest of his life.