Many horse shows and rodeos require your horses to have a current Coggins (within last 12months) to be able to attend. Going across state-lines usually requires one also – though some states have agreements allowing horses to cross without one. North Dakota and South Dakota for example only requires health papers but no Coggins if the horse is native to the states.

So what is Equine Infectious Anemia or EIA?
It is a bloodborne viral disease that is primarily transmitted through biting insects, especially horseflies and deerflies. All equines can be infected with the virus; horses, ponies, donkeys and mules.

This virus is classified as a lentivirus, a subfamily of Retroviruses with a long incubation period. The most well-known lentivirus is Human Immunodeficiency virus (HIV). EIA virus does not cause disease in human or any risk to human health.
The insect bites are primary route of transmission but transmission of blood between horses can also spread virus

Such as:
1. Contaminated needles, syringes or surgical equipment
2. Transfusion of infected blood or blood products
3. Passed on from mare to foal during pregnancy

Outbreaks will typically occur in the late summer or early fall. But an incubation period of 7-45days is common before disease signs are seen after virus infects a horse. The horse will develop an immune response, but it is not effective in eliminating the virus – causing horse to carry virus for life – without a medical cure available either.

Classic cases of disease progress through 3 clinical phases

Acute Phase:
– Last 1-3 days
o Fever
o Depression
o Thrombocytopenia
– Signs can be mild and short-lived causing it to be missed in many horses

Chronic Phase:
Recurrent episodes of
– Fever
– Thrombocytopenia
– Anemia
– Petechiation of mucous membranes
– Dependent edema
– Muscle weakness
– Loss of condition
– Failure for young horses to grow with age (failure to thrive)
Time between episodes can range from days to weeks or months
In most cases; the episodes of clinical disease subside within a year.

Inapparent Phase:
– Infected horses become inapparent carriers and reservoirs of the EIA virus
– These horses often remain clinically normal

Some outbreaks do not follow the books. These outbreaks can be associated with peracute infections were the primary viral infection is uncontrolled causing:

1. Very high fevers
2. Severely reduced platelet counts
3. Acute depression
4. Death

1. No vaccine available
2. Coggins test
a. All horses every year
b. Isolate new horses until they are tested
c. Internationally recognized as the GOLD Standard in diagnosing & helping control EIA
3. Use sterile, disposable needles and syringes
4. Implement good insect controls
a. Insecticides
b. Drainage of standing water
c. Keep stable cleans
d. Dispose of manure away from stabling areas


2019 EIA cases in the United States:
1. June – Kansas
a. 1 horse euthanized & premise under quarantine
2. May & June – Texas
a. 2 premises under quarantine
3. June – Idaho
a. 1 horse euthanized & multiple premises under quarantine
4. May – Tennessee
a. 1 horse euthanized
5. April – Texas
a. 2 premises under quarantine
6. April – Iowa
a. 10 horses euthanized & 30 horse under quarantine
7. March – Texas
a. 2 horses euthanized & 2 premises under quarantine
8. March – North Carolina
a. 1 mule euthanized
9. February – Georgia
a. 2 horses euthanized & premise under quarantine
10. January – Texas
a. 9 horses positive & under quarantine
11. January – Florida
a. Premise under quarantine
12. January – Tennessee
a. 4 horses euthanized & premise under quarantine
13. January — Georgia
a. 3 horses euthanized & premises under quarantine