
On Feb. 17, an Equine Infectious Anemia (EIA) outbreak was confirmed in Weld County, Colorado. A 7-year-old Quarter Horse mare used for racing tested positive for EIA after being exposed to a positive horse in Adams County, Colorado, in December. Two additional horses have also been exposed to the virus.
EDCC Health Watch, a program powered by the Equine Disease Communication Center (EDCC), provides verified equine disease reports to the public. The EDCC is a nonprofit organization supported by industry donations, offering accessible infectious disease information.
Understanding Equine Infectious Anemia (EIA)
Equine infectious anemia is a viral disease that compromises horses’ immune systems. The virus spreads through the exchange of bodily fluids, often via blood-feeding insects like horseflies, or contaminated instruments. A Coggins test screens for EIA antibodies, required by most U.S. states for interstate travel.
Once infected, horses become lifelong carriers of EIA, potentially showing symptoms such as body condition loss, weakness, fever, and anemia. Unfortunately, there is no vaccine or cure for EIA. Infected horses must be euthanized, quarantined at a safe distance from healthy horses, or face strict lifelong isolation.

