Fourth EIA-positive horse identified in Colorado

PROMO 660 x 440 Animal - Horse colt
Published Wednesday, December 5, 2018

The Colorado Department of Agriculture's, State Veterinarian's Office, has been notified that a fourth Colorado horse has tested positive for Equine Infectious Anemia (EIA).  The horse was tested for routine movement purposes in Fremont County, where it is currently under a quarantine order. The investigation is ongoing but appears to be unrelated to the prior three cases of EIA in Colorado this year. The initial test was completed at Colorado State University's Veterinary Diagnostic Laboratory in Rocky Ford with the confirmatory test completed at the National Veterinary Services Laboratory (NVSL) in Ames, Iowa, on December 4, 2018.

"The current risk to the general equine population is low at this time, given that we are at the end of fly vector season in Colorado. This disease occurrence also highlights the importance of disease prevention practices, such as not sharing needles, syringes, tack, and equipment along with routine testing for EIA," said State Veterinarian, Dr. Keith Roehr.

A negative EIA test (Coggins) is required to cross state lines in the United States.  It is also recommended that all equestrian shows, rodeos, fairs, and other equine events consider requiring a negative Coggins for entry, even if the horses haven't crossed state lines.  Coggins tests are also recommended as an important component of a pre-purchase exam.

Update on Prior Cases

  • August 2018 EIA Investigation: The index premises in Weld County and two associated premises have been released from their quarantine and hold orders.  149 exposed horses have been located in Colorado (out of the 149 that we determined to be in the State) at 66 different locations. Fifty-eight hold orders have been lifted in Colorado; 8 hold orders remain in Adams, Boulder, Huerfano, Jefferson, Larimer and Weld counties until final testing is completed.
  • September 2018 EIA Investigation: The index premises and associated premises have been released from their quarantine and hold orders after all horses tested negative for EIA.
  • November 2018 EIA Investigation: All associated horses have tested negative for EIA and have been released from their hold orders.

FAQs about Equine Infectious Anemia

What is 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 can also cause high fever, weakness, weight loss, an enlarged spleen, anemia, weak pulse and even death.

How is it spread?

It is spread most commonly through blood by biting flies such as horse flies and deer flies. It is important for horse owners use fly control methods to reduce disease transmission for EIA and other equine viruses.

What happens to an infected horse?

There is no cure for the disease, so infected animals must be quarantined for life or euthanized.

Is there a danger to people?

No. The disease can only be spread to horses, mules and donkeys.

Is the disease common?

No. There has only been a small number of cases in the United States, although the disease exists in other parts of the world. A map of cases from the year 2001-2017 is available at

How is the disease controlled?

Equine Infectious Anemia is a disease for which horses must be tested annually before they can be transported across state lines. The test for EIA is commonly called a Coggins Test. may earn an affiliate commission if you purchase products or services through links in an article. Prices, when displayed, are accurate at the time of publication but may change over time. Commissions do not influence editorial independence.