Equine Infectious Anemia

Equine infectious Anemia (EIA) is a viral disease transmitted through blood contact in equine species, including horses, donkeys and mules, that can cause fever, weakness, swelling, irregular heartbeat and low red blood cell count. Common sources of transmission are blood-feeding insects such as flies, or with the reuse of infected needles and other contaminated medical, dental or tattoo equipment. It cannot be spread through coughs, sneezes or casual contact. It cannot be transmitted to humans and is not a public health risk.

Horses suspected to be ill should be reported to their veterinarian for appropriate care. Infected horses may not show symptoms but remain carriers for life, making routine testing key to prevention of spread of this disease. This is a reportable disease, meaning when veterinarians diagnose it, they are required to notify the NDA, per NRS 571.160. The NDA website includes a list of reportable diseases.

There is no known treatment for EIA. Infected horses are lifelong carriers of the virus and can potentially infect other horses. Routine testing is important to preventing the potential spread of disease. Management choices for EIA positive horses include either euthanasia or lifelong quarantine with permanent isolation that includes being at least 200 yards from any other horses.

Prevention and control of EIA

Horse owners are urged to practice good horse health safety measures to reduce chances of an infectious disease being transferred, and get as much background information as possible before purchasing horses. Basic practices include:

  • Single-use medical equipment such as needles, syringes, and IV lines should never be re-used, and should never be shared between different horses. Dental tools and other instruments should be fully sterilized between horses.
  • Practice good fly control by keeping stalls dry, removing standing water, managing manure, and using fly deterrents and repellants.
  • Horses should have a routine testing schedule for EIA and should be tested prior to attending events.
  • Test horses at the time of purchase examination. Work with a veterinarian on a quarantine and/or retesting protocol prior to introducing a new horse to current horses. Before purchasing, get as much background information on the horse including any domestic or international travel or importation.
  • Any horses entering the U.S. from other countries require testing and quarantine prior to entry.

Equine species are required to have a Certificate of Veterinary Inspection and a negative EIA (Coggin’s) test within 12 months prior to entry as part of Nevada's entry requirements. Negative EIA tests are required for movement between all states and the U.S. Department of Agriculture lists EIA requirements for importation into the U.S.


As of Aug. 3, 2022, a detection of EIA was confirmed in a horse at a facility in Clark County during routine testing. A quarantine has been issued for the facility and all horses on the premises will undergo testing to prevent potential spread of the disease.

Horses that attended an event in Washoe County within the month of June 2022 are also encouraged to test.

View the Equine Infectious Anemia Quarantine FAQ for additional information. 

Resources and helpful links

Equine Herpes Virus (EHV)