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Thursday, February 17, 2011

Why do we do Coggins' tests each year?

As of March 2, 2011, an updated regulation will take effect regarding the Coggins' test for Equine Infectious Anemia in Virginia. The Virginia Department of Agriculture and Consumer Services (VDACS) has updated the regulation and specifies that "all horses assembled at a show, fair, race meet or other such function or participating in any activity on properties where horses belonging to different owners may come into contact with each other in Virginia must be accompanied by a report of an official negative test for Equine Infectious Anemia". This update further defines what "when horses are assembled" means. Assembly of horses for a trail ride on public property such as a state park is an example of an activity requiring horse owners to have a valid Coggins report with them.

Starting March 2, rangers in state and national parks may check for Coggins' papers and owners without valid test reports could be charged with a Class I Misdemeanor and asked to leave the park. As is currently the case under existing regulations, owners presenting fraudulent paperwork can be charged with civil penalties as well.

The Coggins' test is laboratory test for the disease Equine Infectious Anemia(EIA). EIA is a very contagious (infectious) and possibly fatal disease that affects any species of equines (horses, donkey, mules, etc). It is caused by a virus, a type classified as a retrovirus. There is no vaccine or treatment for the disease. EIA is a blood-borne infection and can be transmitted from horse to horse by large biting insects (horse flies, deer flies) or from blood-contaminated materials.

There are three clinical forms of the disease: Acute, Chronic, and Inapparent. In the Acute form, if a horse is exposed the the EIA virus, they can develop severe signs (fever) of the disease and die within 2 - 3 weeks. In more mildly affected horses, there may an initial fever that resolves and the horse recovers without further symptoms but if this horse is then interacting with other horses, it may act as a potential source of infection for any horse living in its vicinity. There may be no indication at all of the disease until picked up by a routine annual Coggins' test.

In the Chronic form, the horse survives the acute bout of the disease and may develop recurring bouts of illness. Symptoms of this illness may include moderate to high fevers (105 F), petechial hemorrhages (pin point blood spots on mucous membranes or gums), depression/lethargy, weight loss, edema in limbs or underbody surfaces such as the chest or belly, and anemia.

In the Inapparent form, the horse carries the disease with no signs or symptoms of illness. However, they serve as "resevoirs" of infection. The majority of horses positive for EIA are in this category. These horses are carriers for life and the infection may become chronic or acute when under stress from hard work, transportation stress, or when dealing with another illness. Inapparent carriers have lower concentrations of the EIA virus in the bloodstream than horses with active clinical signs of EIA. It is said that only 1 horse fly out of 6 million is likely to pick up and transmit the virus from such horses.

Prevention of EIA is centered around identifying carriers and affected individuals and removing them from contact with other horses. When an equine has a positive result on an official test for EIA, the animal is placed under quarantine. Confirmation testing is initiated and the quarantine from other horses is in order to prevent further exposure and possible transmission of the disease. All exposed horses within 200 yards of the location of the "positive horse" must also be placed under quarantine. The quarantined area and horses are monitored by federal or state regulatory personnel. For more information on EIA Uniform Methods and Rules to implement and conduct a national control program for EIA formulated by APHIS-VS, go to http://ww.aphis.usda.gov/vs/nahps/equine/eia or contact an area APHIS - VS office.

"Equine Infectious Anemia is a serious disease," said Dr. Richard Wilkes, VDACS State Veterinarian. "It affects all members of the equine species and is found in nearly every country of the world. All infected horses, even those that are asympotmatic, become carriers and are infectious for life. Infected animals must either be destroyed or remain permanently isolated from other equines to prevent transmission. The change in regulation is not drastic, but it is important and horse owners need to take seriously the need for a valid Coggins test each year prior to anny assemblage with other equines."