A case of Equine Infectious Anemia (EIA) in Weld County, Colo., has large animal practitioners working overtime, as the Colorado Department of Agriculture's State Veterinarian's Office continues their investigation into the EIA-positive horse in Colorado.  

The Colorado Department of Agriculture, State Veterinarian’s Office, was notified by the US Department of Agriculture’s National Veterinary Services Laboratory (NVSL) that a Weld County horse tested positive for Equine Infectious Anemia (EIA). The initial test result was received on August 24, 2018, with a re-test confirmation on August 28, 2018.  

According to a press release published by the Colorado Department of Agriculture (CDA) last Friday, with the help of records from CDA's Brand Division and Rocky Mountain Regional Animal Health Laboratory, the States Veterinarian's Office has determined that approximately 240 horses have been on the quarantined premises during the same time as the positive animal.

Approximately 100 of these horses were sent to 20 other states across the country and steps are being taken to locate, quarantine, and re-test those horses. At this time, no other horses have tested positive for EIA.

Since there is no cure or treatment for EIA, the infected horse has since been euthanized. However, the index premises in Weld County is under a quarantine order, along with two other associated premises.

According to the CDA, fifteen additional premises are under hold orders in nine Colorado counties: Adams, Arapahoe, Crowley, Delta, Douglas, El Paso, Mesa, Montrose, and Weld. Thirty-seven exposed horses have been located in Colorado, and more are being traced through an ongoing investigation.

Under the Livestock Security Act, the names and locations of the premises and owners are protected and can only be used for investigations and other official use.

"We are working to locate approximately 140 horses that went to different premises across Colorado. We are asking horse owners to contact us if they purchased horses in Weld County between July 18 to August 20, 2018," said State Veterinarian, Dr. Keith Roehr. "We will work with owners to see if their horses came from the quarantined property. This is an important step in the disease investigation."

The Quarantine and Hold orders will remain in place until the exposed horses on the premises test negative at the 60-day re-test.  This re-test date is 60 days from the last known date of exposure to the positive horse.  A quarantine is issued to a location that housed an EIA-infected horse. A hold order is issued when horses had contact with an infected horse but have not tested positive for EIA and are being held for re-testing.  Both quarantine and hold orders include movement restrictions.
CDA is actively monitoring and working to ensure compliance with the quarantine of the index premises and the hold orders issued for premises with exposed horses.  The Department does have the legal authority to pursue civil fines against those who violate a quarantine, hold orders, or animal health requirement rules.  Due to state laws and regulations, CDA is limited by the details that can be shared regarding individual operations under investigation, quarantine, or hold orders.

About Equine Infectious Anemia:

Equine Infectious Anemia is a viral disease spread by bloodsucking insects, inappropriate use of needles, or other equipment used between susceptible equine animals such as horses, mules, and donkeys. Horses may not appear to have any symptoms of the disease, although it also can cause high fever, weakness, weight loss, an enlarged spleen, anemia, weak pulse, and even death.
EIA is spread most commonly through blood by biting flies such as horse flies and deer flies. Since there is no cure for the disease, infected animals must be quarantined for life or euthanized.
EIA can only be spread to horses, mules, and donkeys. There has only been a small number of cases of EIA in the United States, but the disease exists in other parts of the world.
Horses must be tested for EIA annually before they can be transported across state lines. The test for EIA is commonly called a Coggins Test.