State Veterinarian Offers Advice to Uintah Basin Horse Owners and Facts about Equine Infectious Anemia

Horse, mule or donkey owners in Utah's Uintah Basin are advised to not let their animals mingle with wild horses or take their animals onto Ute Nation lands or BLM land adjacent to that land until an outbreak of Equine Infectious Anemia (EIA) is brought under control. Equine owners in that area are also advised to use a fly-wipe on their animals to help prevent the spread of the disease.

EIA is a viral disease of horses, mules and donkeys. It has been recognized in the United States for 80 years and other countries prior to that. The virus is spread under natural conditions by insect vectors. Transmission is mechanical and requires a carrier animal, a vector, and a susceptible host. It is not spread by animal waste or harbored by physical facilities. The disease may be acute, subacute, or chronic. The incubation period is generally 12-15 days but may extend up to 2 months. The acute form begins with a temperature elevation, followed by weakness, uncoordination, rapid respiration, weight loss, anemia, and subcutaneous edema. Death may result in 15-30 days or the animal may develop a subacute form of the disease characterized by marked anemia. Some animals show only the chronic form with or without acute flare-ups.

Chronic cases with a low viremia offer a chance of spread but over a longer time period. They may carry the virus in their blood for several years, posing a risk to other animals . There is no vaccine for the disease. Fortunately, animals which have been exposed to the disease can be detected by a blood test known as the Coggins Test, named after Dr. Leroy Coggins who developed it. It is our best tool in controlling this devastating disease. Utah & all the bordering states require this test prior to entry.

Each year Utah tests over 7,000 animals. On average, one to three animals in Utah are found to be positive. Recently, 30 animals from a free running herd tested positive. The affected herds are located on the White River drainage east from Ouray and on the Hill Creek drainage south from Ouray and are distributed along those drainages. The disease may have been introduced many years ago by animals imported to Utah without proper tests or health certificates.

The herd on the White River is a privately owned herd and has been gathered. This year 585 horses in that herd were gathered and 233 were tested for EIA with 27 of those testing positive. We have been experiencing a few cases of EIA for several years in privately owned horses who have been in proximity to this herd. Some of the animals have shown signs of the disease and deaths have been reported in symptomatic animals that tested positive to EIA.

The herds on Hill Creek are privately owned by the Ute Tribe. They are interested in gathering this herd to improve range conditions and to assess the degree of infection in those horses. They have asked for the assistance of the Utah Department of Agriculture in testing those animals. There is also a herd of horses on BLM ground neighboring the reservation. Some of these herds are free to move at will. The BLM detected EIA in one horse in their herd in 1996 and will be gathering their animals simultaneously with the tribe. The BLM will be testing their animals and releasing the negative animals back to the range.

All the parties involved regard this as a unique opportunity to eliminate the disease from the area. Tribal members, private horse owners, and government agencies are cooperating in this unprecedented effort. The threat of this disease will be significantly reduced or eliminated.

Posted 30 April 1998