Coggins Test and Equine Infectious Anemia (EIA)

The perfect horse article "Equine Infectious Anemia Continues to Kill," was not complete and is somewhat misleading, as anyone who has endured an outbreak of EIA positives can attest.

Such an outbreak occurred circa 1990 in southeastern Pennsylvania. EIA as a disease was reported to be 30% fatal in symptomatic horses at the time. However, the Coggins test was 100% fatal-regardless of symptoms. While Dr. Eleanor Kellon describes the tests and symptoms accurately, she does not state that regardless of the outcome of other tests, a positive Coggins is a death sentence in all jurisdictions that use it.

The Coggins test does not test for the actual virus that causes EIA. It tests for antibodies to the virus. This virus is similar to HIV and, like any pathogen, causes the exposed body to generate antigens and antibodies. Most vaccines for humans and horses use killed viruses or viruses that are genetically altered not to be infectious. The first AIDS tests were for the antibodies and there were some who thought positive for antibodies should be a death sentence for the infected.

We cannot vaccinate against EIA because the only legally recognized test for the disease does not test for the disease itself, but for the antibodies the vaccine will stimulate. The statutes regarding EIA are what are killing horses, not the disease, in most cases.

The disease requires a serum transfer with a sufficient dosage of the live virus to cause active infection. The natural vector is the large horse fly. A horse with a large pool of the virus when bitten may coat the mandibles of the fly with enough serum to infect another horse if the fly bites while the serum is still wet and the virus viable. The latency seemed to be about 30 days.

To add insult to injury, the owner must pay his vet to draw and test the blood samples that will condemn his horse, pay to have the animal destroyed and disposed of, and cannot collect insurance or any compensation for the animal.

Even if the owner opts for a more expensive test that actually detects the virus, he cannot save an animal that has antibodies because the only test that counts is the Coggins test. In some jurisdictions, a two-in-a-row, 30-days-apart rule applies, but many owners cannot live with the quarantine signs on their barns for 60-90 days and just kill the horse or sell it for meat.

If you want to eradicate a disease, make it attractive for owners to do so. Make the tests free and mandatory on an annual basis. Test for the virus, not the antibodies, at least on the verification tests, and do not kill unless the virus is present. Compensate owners of horses as we compensate cattle owners, chicken owners, and others who lose animals to mandated destruction programs.

The disease did not kill my horse, a government order did. A symptomatic horse survived in quarantine, and another came clear on the second and third tests. All were in the same barn, same paddocks, and we rode together for years. There were no other positives in an 80-stall barn over a 120-day period that surveillance was in place.

New Vaccine May Offer Reprieve
By Eleanor Kellon, VMD

Mr. Lichtenstein very eloquently expresses the anguish, confusion and anger that every owner feels if his or her apparently healthy horse turns out to have a positive Coggins test. However, a few more details about this disease may help owners understand why the Coggins test continues to be used.

The virus that causes equine infectious anemia is a lentivirus, part of the same family of viruses that causes AIDS in people. One of the most important things to realize is that once infected with this virus, the horse remains infected for life. The first wave of symptoms occur 3 to 4 weeks after initial infection, ranging from a fever that may go undetected to more severe signs of fever, lethargy, edema, anemia, low platelet counts, and even diarrhea.