Several recent, confirmed cases of equine infectious anemia (EIA) are a warning to North Dakota horse owners to be aware of the possibility that their horses may have contacted the disease, says the state veterinarian.


Dr. Larry Schuler said that five horses in North Dakota have recently been diagnosed with the disease, and that one of the animals has died. Although three different owners are involved, Schuler said all the animals had been in contact with each other, and it is possible that all the cases are linked to a common source.


“The number of animals involved is fairly significant,” Schuler said. “Usually we have only one case every two or three years.”


A viral disease, EIA is generally spread by larger blood-sucking insects, such as horse flies and deer flies. The infection can also be spread mechanically through use of unclean hypodermic needles. One-fifth of a teaspoon of blood from a horse with acute EIA contains enough of the virus to infect a million horses.


EIA can readily be detected through a procedure known as a Coggins test. North Dakota and many other states require that all horses coming into the state have a negative Coggins test.


Symptoms include fever, small blood-colored spots appearing on the mucous membranes, depression, swellings in the legs and under the chest, and general anemia. The disease can be fatal to horses, but animals can also develop a chronic form of the disease with recurrent symptoms. No vaccine is presently available.


EIA poses no threat to human health, except to individuals with suppressed immune systems.



  • Schuler said horse owners can take a number of precautions t