What Is Equine Infectious Anaemia and the Coggins Test?
Short answer
Equine infectious anaemia (EIA) is a blood-borne virus disease of horses, and the Coggins test can help detect antibodies to it, even in a horse that looks healthy. EIA is a notifiable disease.
For: Horses Adult Horse
By Pashupatinath Vet Lab Share
Equine infectious anaemia, or EIA, is a virus disease of horses that spreads through blood. The Coggins test is a blood test that can help detect antibodies to the EIA virus, even in a horse that looks perfectly healthy. Buyers, event organisers and authorities often ask for it, and EIA is a notifiable disease.
What is EIA and how does it spread?
EIA is caused by a virus that attacks a horse's blood cells and its defences against illness. It passes on when blood from an infected horse reaches another horse. Blood-feeding flies, such as horse flies, can carry a tiny amount of blood on their mouthparts from one animal to the next. A needle, syringe or tool used on more than one horse without proper cleaning can do the same.
EIA does not infect people. It is a disease of horses, but it matters to every stable that buys, sells or travels with them.
Why can a healthy-looking horse carry it?
Some infected horses fall ill. They may run a fever that comes and goes, grow weak, lose weight, develop swollen lower legs or belly, and show pale gums because of anaemia, which means too few red blood cells. Other infected horses have only mild signs, or none, and look quite normal for long stretches.
A horse that has caught the virus stays infected for life, even when it looks well, and it can still pass the virus on through blood and flies. That is why EIA is checked with a test and not by eye.
What does the Coggins test look for?
The Equine Infectious Anaemia (EIA) - Coggins / AGID Test uses serum, the clear liquid that separates from clotted blood. It looks for antibodies, the proteins a horse's body makes after meeting the virus. In the classic Coggins method, called agar gel immunodiffusion, serum is placed beside virus protein on a gel, and a visible line forms where antibodies meet it. ELISA is another method, and the lab confirms which one is used when you book.
There are two limits to remember. A very early infection can still test negative, because antibodies take time to build up. And a young foal can carry its mother's antibodies in its blood and test positive without being infected itself. Your vet reads such results with extra care.
Who asks for the test, and what if it is positive?
Sellers and buyers, breeding stables, racing and show organisers and some authorities may ask for a recent negative result before a horse is bought, moved or entered. It is wise to ask early what is required, because a missing report can delay a plan.
EIA is notifiable, so owners should tell their veterinarian or the animal husbandry department about a positive result or a horse they suspect has the disease. A vet may repeat the test or use a second method to be sure. What happens to a positive horse is a decision for your vet and the authorities, and no lab report alone can settle it.
Where does a blood count fit in?
A Complete Blood Count (CBC) counts red cells, white cells and platelets. In a feverish, weak horse it can help show anaemia, which is common in EIA. It cannot say what caused the anaemia, since tick-borne parasites and other illnesses can do the same. Think of the Coggins test as the one that looks for the virus, and the blood count as the one that shows its effect on the blood.
Some owners like to book several horse checks together. The Horse Disease Screening Pack typically groups the Coggins test with tests for glanders, surra and tick fever, and the exact list is confirmed when you book. A registered veterinarian reads every result with the horse's signs, travel and contact history.
Read next
Another notifiable disease that horse owners are often asked about is described in Glanders in Horses: Signs, Risk to People and Testing. If a sale or an event has a deadline, How Long Do Lab Reports Take, and Why It Varies explains why timing differs and how to allow room for it.
Testing in Bhopal
Your vet usually draws the blood, and for horses in Bhopal the lab will collect the tube from you free of charge. The lab is at C-200, C Sector, Shahpura. Stables in other districts can send serum by courier, bus parcel or through their own vet. Ring or message +91 88175 01118 on WhatsApp, and the lab will confirm the method, sample needs and reporting time when you book, which is worth doing well before any deadline.
This article is general information and does not replace a veterinarian’s advice. Please talk to a registered veterinarian about your animal’s signs, tests and treatment.