22/07/2025
Most equine owners know that a negative Coggins test is a document required to be able to transport their animal across state lines, enter them in a competitive event, or board at someone's barn. But what does the phrase "negative Coggins test" actually mean?
A "Coggins" is a blood test that can only be performed by USDA-approved laboratories and checks for Equine Infectious Anemia (EIA) antibodies in the blood. EIA is a potentially fatal blood-borne infectious viral disease that is primarily transmitted by biting flies, particularly horseflies—which means that your animals are at risk even if they never travel or live in a closed herd.
The clinical signs of disease can vary dramatically from an acute infection to an inapparent form, but what is important to know is that it produces a persistent infection. Once an animal tests positive for EIA it becomes a lifelong source of disease transmission, so the owner can only choose between quarantine for life or humane euthanasia to ensure that large outbreaks of the disease don’t occur. There is no vaccine and no treatment for EIA.
Take-home message: While a Coggins test is a necessary travel document, don’t forget that it's also first and foremost a way to identify and remove EIA carriers to keep the disease under control.
To learn more about EIA, visit our website at: https://aaep.org/resource/equine-infectious-anemia/
or visit the Equine Disease Communication Center's website: https://www.equinediseasecc.org/
