What Is the Coggins' Test?

The Coggins' test is for a serious equine virus calledpersistent virus for which antigenic drift was defined.
equine infectious anemia (EIA). There is no vaccine or(Antigenic drift is the virus's ability to change its form
cure for EIA, which is also known as "swamp fever"sufficiently so that it is no longer vulnerable to existing
because of the warm, wet regions of the Unitedantibodies.)"
States in which it is more common.To determine if a horse is negative on a Coggins' test,
There are three stages to EIA. The acute stage isa blood sample from the horse is tested for the
when the horse shows the symptoms of the disease,presence of EIA antibodies. Antibodies are proteins
which include fever; listlessness; swelling in the chest,produced by the immune system that recognizes and
belly or legs; and no appetite. Although, while thehelps fight infections and other foreign substances in
infection progresses, he may not show any symptomsthe body. The antibody is specific to the EIA antigen (a
at all, and it may take over a month for the horse toforeign substance causing an immune response).
test positive on the Coggins' test.The Coggins' test was developed by Dr. Leroy
According to the Indiana State Board of Animal Health,Coggins, a veterinary virologist, in the 1970s. According
between 30 and 50 percent of horses infected withto the Animal Disease Diagnostic Laboratory at
EIA die within two to four weeks of showing initialPurdue University, the test has a 95% accuracy rate
symptoms.and is the most used test for EIA though other tests
Horses that survive the acute phase enter the chroniccan be used when the results are questionable or to
phase where they will have recurring symptoms of theconfirm diagnosis.
disease including weight loss, fever and anemia. SuchAccording to the USDA APHIS, the percentage of
horses can survive up to a year or more in this stagepositives for the Coggins' test has declined from
before finally succumbing to the disease. While"nearly 4 percent in 1972 to less than 0.01 percent in
appearing healthy at some times, horses can2005." The agency states that historically the disease
experience acute episodes again when under stresswas present particularly in "hot zones" such as Texas,
such as when faced with hot weather, hard work orOklahoma, Louisiana, Missouri, Tennessee, Alabama,
other disease, according to the Indiana State Board ofGeorgia, North and South Caroline, Virginia, Kentucky,
Animal Health.among others. Recent figures show that the
EIA is transmitted to horses by insects such asprevalence of EIA in the United States is roughly less
deerflies and horseflies. It can also be transmitted tothan 8 in 100,000, according to the USDA APHIS.
horses through instruments contaminated with infectedMany states have different requirements with regard
blood such as needles or tattoo equipment.to handling horses positive for EIA. Because there is no
Some horses can also be in the asymptomatic carriercure for the disease, and a horse positive for it is a
stage where they do not show any signs of diseasethreat to healthy horses, many states require
but will test positive on the Coggins' test. But theseeuthanasia. Others allow for very strict quarantine
horses can also experience acute episodes whenmeasures, where horses are removed from the herd
stressed. The Indiana State Board of Animal Healthand kept in a 200-yard buffer zone away from all
notes that these horses in the asymptomatic carrierother horses. Some require confinement to a screened
stage present the greatest danger to healthy horses install. Isolated horses are to never have contact with
public gatherings like horse shows or clinics becausewith the rest of the herd again.
they appear healthy.Though EIA is low in incidence in the United States, to
Surviving horses are unable to completely clearreduce risk of horses being infected with EIA, the
themselves of the virus and will remain infected for theUSDA APHIS recommends horseowners:
rest of their lives, according to the Animal DiseaseNever share needles among horses. Dispose of
Diagnostic Laboratory at Purdue University. Affectiveneedles after each use.
control of the disease depends on isolation of new,Sterilize instruments thoroughly after each use.
sick, untested or positively testing horses; hygiene withKeep stables and area clean and drained to avoid
regard to needles and like equipment such as dentalattracting insects that spread the disease.
tools, fly control and identification of positive animals.Use insect control such as insecticides.
Horse owners are often required to submit a negativeQuarantine unhealthy, infected animals. Do not breed
Coggins' test in order to show, move to a new stable,horses that have tested positive to EIA.
sell their horse or transport their horse across stateQuarantine all horse species that are new to your
lines. A negative Coggins' test proves that your horsefacility until you have a Coggins' test.
is safe to have around other healthy horses.Have the Coggins' test result done and available for
According to the US Department of Agriculturehorse shows, fairs, and other places where animals
(USDA) Animal and Plant Health Inspection Serviceco-mingle.
(APHIS) fact sheet on the EIA virus, it is the "firstFollow state laws concerning EIA.