The Coggins Test is named after its developer Dr. Jack Coggins. This test was developed to screen for Equine Infectious Anemia. (EIA) EIA, also known as swamp fever, is a chronic wasting disease. Clinical signs include intermittent fever, depression, progressive weight loss and weakness, and of course, anemia. Horses may also be infected but be asymptomatic. The virus will persist in the white blood cells of infected horses for life. This means that some horses may be asymptomatic carriers. Transmission occurs via transfer of infected blood from one horse to another. This is most commonly is done by Tabanid flies. These are large black horse flies. Infection may also occur from contaminated needles or surgical instruments.
EIA is a disease of world wide importance. It is also a disease that an active eradication program exists. Proof of a negative Coggins test required for international shipment and well as for interstate transport. Each state has laws that provide further restrictions. Proof of a negative Coggins is required for the sale of all horses. It is typically supplied by the sellers. Most auctions will not accept horses without proof of negative Coggins. Coggins are also required when horses owned by more than one person are brought together. These events may be shows, trail rides, rodeos, etc. They are also required when horses are boarded. Those who provide boarding services are expected to keep copies of the negative coggins on the premises.
A positive result these days is relatively rare. The testing process has been going on since the 1960’s-1970’s. This has greatly reduce the pool of positive carriers. If a positive result should occur, the lab will retest the sample to confirm. At which time the state veterinarian will take over. The premises the horse is stabled at will be quarantined as well as any other horses the infected horse may have come in contact with. All of these horses will be retested. Negative horses will continue to be held in quarantine until the end of the incubation period which can be up to three months.
Positive horses have three options under the law. Due to current situations only two are available. In times past, positive horses could be sold for slaughter. Since there are no active slaughter houses at this time, this option is not available. The two that are left are euthanasia and isolation. If isolation is elected, the positive horse must be placed in a situation where he can not come within 200 yards of a non-infected horse. The 200 yard limit is because that is how far a Tabanid will fly to change hosts.
Currently, the Coggins test is the piece of paper we must have to move our horses. Under most circumstances, it is required annually. A more recent coggins may be required for some shows or international transport.