For starters, Coggins is a test not a disease. The Coggins Test is a diagnostic tool to analyze a horse’s blood for the presence of
antibodies to Equine Infectious Anemia Virus (EIAV). Blood is drawn by an accredited veterinarian and submitted with
paperwork, indicating the horse’s markings and current location, to an approved lab for testing with the Coggins Test. This test
is required by all states to cross the border with only a few exceptions. Some states also require it for change of ownership,
trail riding, and shows. Once tested, the paperwork is only good for a year, or less in some states, so the horse must be
retested.
What is it?EIAV, also known as Swamp Fever, is a retrovirus virus that makes its own DNA. This DNA is incorporated into the genetic material of the horse’s infected cells. First diagnosed in the US in 1888, it causes 3 different clinical presentations, an acute form, a chronic form and an inapparent form.
The acute form is the most devastating and difficult to diagnose of the presentations. When exposed, the horses can become gravely ill and die within 2 to 3 weeks sometimes, the only sign being a fever short after exposure. Many times, this fever is gone long before the horse is examined by a veterinarian. This stage is the most dangerous to other horses as 1/5th of a teaspoon of blood from an acute form horse can infect over a million horses. If the horse recovers from the acute form, it can continue into one of two other forms.
In the chronic form, the horse has recurring problems including high fevers, anemia, weight loss, and depression. The anemia also causes small blood spots in the mucus membranes called petechial hemorrhages and edema in the lower legs and under the belly and chest.
The 3rd is the inapparent form and is the most common form detected in horses. No signs of disease are shown by these horses and are usually only found with routine annual testing. In this form, the virus load is extremely low, yet, it is the most common source of the virus for other horses. The infection is for life and can change forms if the horse is stressed or becomes ill from a second disease.
