Equine infectious anemia has been a real problem in many southern states in the past. You can never be too cautious, especially when you travel with your horses. Strict laws with harsh punishments for violators have dramatically improved this killer disease, even in our less-affected state.
“Equine infectious anemia is a viral disease; it’s the same type of virus that causes HIV in people and feline leukemia in cats,” Marci Jennings, Equine Instructor and Extension Specialist with the University of Missouri, warned. She said it was considered a contagious disease mostly because it could be passed through horse flies and other vectors. “If they get a large enough amount of blood, it can be passed on,” she noted.
One of the most common ways we can spread the disease between our horses is by not changing out needles when we’re giving vaccinations to multiple animals.

How It Hurts
Jennings explained the disease actually mutates once it’s in the body. It becomes incorporated into different cells by splicing itself, which causes anemia. Anemia is the primary symptom and is the disease’s namesake.

Three Stages of the Disease
There are three stages of which a horse can have equine infectious anemia.
1. Acute stage
Five to 30 days after exposure the horses will usually have an increased temperature. They will be really lethargic, they won’t be eating. This is a short lived stage, Jennings said. Acute equine infectious anemia “is the most serious and the largest number of deaths in horses occur in this stage,” Jennings noted. She added, however, that the number of horses actually infected at this stage are lower. Although not many will contract the acute stage, once a horse is infected, they have the highest risk of infecting other horses. “A small amount of blood in those animals can cause the disease in others,” she warned.
2. Chronic stage
“This is where the horse will have bouts of fever, depression, anemia, they become horses hard to keep weight on,” Jennings said. She explained it would take more blood transfer from a chronic stage horse to infect other animals.
3. Inapparent stage.
This is the most common stage. Horses who have inapparent equine infectious anemia won’t have any outward sign of the disease. According to APHIS (The Animal and Plant Health Inspection Service) One horsefly out of 6 million would transfer equine infectious anemia from an inapparent carrier, Jennings cited.

Preventing the Spread
Coggins is the actual test to determine if your horse has equine infectious anemia. The veterinarian’s name who invented the test was Leroy Coggins. The disease is also known as swamp fever. It’s most prevalent in southern states where it’s warmer, more humid conditions, more vectors around to transfer, Jennings said.
“The tricky thing as far as testing, it’s unsure what percentage of the population are being tested. The kinds of horses being tested are higher quality horses,” Jennings said.
The prevalence of the disease has gone down due to legislation that has required testing on horses. Part of that legislation is put together by the USDA. Each state has their own take on what the USDA and APHIS require.
“Pretty much what APHIS requires is any horse traveling over state lines, and any horse that is being sold must have a current Coggins test, pretty much across the board from what I’m aware of,” Jennings said.

What is the best prevention?
“The biggest prevention is an annual test on all of your horses. That’s the biggest. Especially if you’re not sure if the animals you’re around have been exposed. Also checking Coggins tests on horses coming to your farm is a good idea. Also, decrease the fly population. If you don’t have the vectors and you’re not reusing needles then you will likely not spread,” Jennings said.
Jennings noted that research is being done in quite a few different places, but it is very difficult to find a vaccine because the disease mutates quickly, just like HIV. A lot of that research is being linked between HIV because the viruses are similar. Research on this disease could potentially transfer into the human world.

What are the laws concerning testing in Missouri?
Missouri requires negative EIA tests within 12 months for all events for horse rodeos, trail rides and shows.
The state also requires 12 months Coggins for sale, trade or exchange of horses. Any horses at a breeding, boarding or training facility must have a current Coggins test.
Missouri does not require testing on foals six months or younger. Once they’re weaned it’s required.
Penalty in the state is a max $10,000 per violation. If you’re having an event or you’re managing the facility it’s your responsibility to make sure all horses present are tested.
But, Jennings cited a recent study that proves these efforts at containment are paying off in Missouri. In 1996 there were 35 positive horses found. In 2006? Only three.


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