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Equine Infectious Anemia

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Equine infectious anemia (EIA) is a viral, and sometimes fatal, disease that only

affects equids (horses, ponies, zebras, mules, and donkeys). There is no treatment.

EIA can be difficult to recognize and may be confused with other diseases. It is found

in nearly all countries worldwide, including the United States. It is a reportable

animal disease in all States. It is not a threat to human health.
Clinical signs range from mild to severe and appear within a few weeks after

infection. However, it may take 60 days or more for the horse to test positive.

Infected animals that survive the disease become virus carriers and can infect other

equids for life. They must either be euthanized or permanently isolated from other

equids to prevent transmission. Carriers may also experience clinical flare-ups, often

following stress or strenuous work.

What To Look For

Fever

Decreased appetite

Severe anemia

Sudden death

Jaundice (yellow discoloration of mucous membranes)

Rapid breathing, rapid heart rate

Swollen limbs

Bleeding from the nose or red/purple spots on mucous membranes

Blood-stained feces

Chronically infected horses may show no clinical signs.

How To Prevent This Disease

Biting, blood-feeding flies, such as horseflies or deerflies, can spread the virus from

one animal to another. Historically, this has been the primary way EIA has spread.

Animals can also get the virus from unclean or re-used needles and syringes, blood

transfusions, and contaminated instruments, such as IV sets, dental instruments,

and tattoo equipment. This type of human-facilitated transmission is now the most

common way EIA spreads in the United States, particularly among current or former

Quarter Horse racehorses, many with ties to unsanctioned (bushtrack) racing.

To prevent the spread of this disease:

Control biting flies on your property to reduce your animal's exposure.
Never reuse needles, syringes, or IV sets.

Only use licensed and approved blood products.

Make sure blood transfusions are performed only by licensed veterinarians

using blood products from donor horses that have tested negative for EIA and

other blood-borne infections like equine piroplasmosis.

Test your horses, ponies, mules, and donkeys annually for EIA.

Call your veterinarian if you suspect EIA in any equid. Immediately move

horses, ponies, mules, or donkeys that you think might have EIA at least 200

yards away from other equids on your property.

How It Is Treated

There is no treatment or vaccine. Because infected animals become lifelong carriers,

they must be permanently isolated and quarantined or euthanized.

Report Signs of Animal Disease

Producers or owners who suspect an animal disease should contact their

veterinarian to evaluate the animal or herd. Find an accredited veterinarian.

Animal health professionals (veterinarians; diagnostic laboratories; public health,

zoo, or wildlife personnel; and others) report diagnosed or suspected cases of

nationally listed reportable animal diseases to APHIS District Offices and to the State

animal health official as applicable under State reporting regulations. 

Controlling Equine Infectious Anemia

APHIS' Response

Efforts to control equine infectious anemia in the United States started in 1972.

Since then, the estimated national prevalence of EIA infection in the U.S. equine

population has dropped from nearly 4 percent in 1972 to 0.004 percent.

2022 Summary of Equine Infectious Anemia Cases in the United States

2021 Summary of Equine Infectious Anemia Cases in the United States
2020 Summary of Equine Infectious Anemia Cases in the United States

2019 Summary of Equine Infectious Anemia Cases in the United States

2018 Summary of Equine Infectious Anemia Cases in the United States

To request copies of previous years' reports, send an email to aphisweb@usda.gov.

Uniform Methods and Rules

The Uniform Methods and Rules (70.92 KB) contains minimum recommended

standards for detecting, controlling, and preventing EIA.

Information for Laboratories

VSG 15201.1 (426.82 KB) Approval of Labs to Conduct EIA Testing (effective

2019)

VSG 15201.1 Official Documents:

EIA Laboratory Monthly Data Report TEMPLATE (72.75 KB) (MS-Excel file,

2020)

VS 10-16 (92.75 KB) Application To Conduct EIA Testing

VS 10-15 (104.97 KB) (Director’s) Agreement To Conduct EIA Testing

VS 10-17 (468.96 KB) Laboratory Inspection Checklist for EIA Labs (2020)

VSG 15201.1 Outreach, Training and Explanatory Information:

FAQ 15201.1 (196.16 KB) (2019)

15201.1 Requirements Actions (270.86 KB) (2020)

Documentation Requirements for Non-Negative EIA Results

Current List of Approved EIA Laboratories

List of Approved EIA Test Forms

EIA Lab Approval Webinar Recording

Information for Veterinarians

Only Category II accredited veterinarians, who are authorized to perform accredited

duties in the State in which samples are collected, may submit samples to an APHISapproved laboratory. You must include your National Accreditation Number (NAN)
with every submission.

Check your accreditation status

Submitting Samples

Accredited veterinarians must complete a VS 10-11 form either electronically or by

paper using one of the USDA-approved systems or forms from the List of Approved

EIA Test Forms (155.06 KB) and submit samples to APHIS-approved labs. Contact

your State's APHIS Veterinary Services District Office with questions or to request

paper copies of the form. Note: The form is not available as a fillable PDF.

View instructions for completing VS Form 10-11 (420.24 KB)

Post-Mortem Lesions

Spleen, liver, and abdominal lymph nodes may be enlarged. Mucous membranes can

be pale. In chronic cases, emaciation may also be noted. However, horses that die

between clinical episodes may have no gross lesions.