CDA provides update on 3 separate equine health concerns in Colo. |

CDA provides update on 3 separate equine health concerns in Colo.

Colorado Department of Agriculture

BROOMFIELD, Colo. — In an effort to prevent confusion, the Colorado Department of Agriculture is providing an update on three separate equine health concerns currently affecting horses in Colorado. There are confirmed cases of Equine Infectious Anemia, Equine Herpesvirus Myeloencephalitis and Strangles.

“The Colorado Department of Agriculture is working with the equine industry and veterinarians to contain the spread of these diseases. An important reminder is that owners should always practice proper disease prevention practices for their horses. Proper sanitation and biosecurity is often the first step in protecting your horse,” said State Veterinarian Keith Roehr.

Note: CDA provides disease control information on the county level; the exact locations of these cases cannot be disclosed as it is protected by a number of state statutes that limit the information that can be shared about livestock premises, livestock operations, the animals, specific locations of infected animals or other livestock proprietary information.


On May 4, 2017, the CDA, State Veterinarian’s Office, was notified by the U.S. Department of Agriculture’s National Veterinary Services Laboratory that a Weld County horse tested positive for EIA. There are now two additional cases of EIA at the same location, these horses belong to the same owner. All three horses have been euthanized. The Weld County facility is currently under a quarantine order that restricts movement of horses until further testing is completed by CDA.

EIA 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. Infected horses may not appear to have any clinical signs of the disease, although it can cause high fever, weakness, weight loss, an enlarged spleen, anemia, weak pulse and even death. There is no cure for the disease, so infected animals have to be quarantined for life or euthanized. EIA is not transmissible to people.

EIA 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.


The CDA is investigating a confirmed case of Equine Herpesvirus Myeloencephalitis, which is a form of Equine Herpes Virus (EHV-1), within the state; a Mesa County premises has been placed under quarantine. The horse was quarantined after showing neurological clinical signs associated with the disease and subsequently testing positive for EHV-1. Currently the horse is under private veterinary care and seems to be making a good recovery. The horse had been to events over the previous two weeks, and all of those events have been notified. Event organizers are communicating with participants to monitor their horses for signs of the disease, especially for fever (temperature over 101.5 degrees F).

EHV-1 is not transmissible to people; it can be a serious disease of horses that can cause respiratory, neurologic disease and death. The most common way for EHV-1 to spread is by direct horse-to-horse contact. The virus can also spread through the air, and indirectly through contaminated equipment, clothing and hands. Proper biosecurity practices are vital to preventing the spread of this virus.

Clinical signs include fever, decreased coordination, nasal discharge, urine dribbling, loss of tail tone, hind limb weakness, leaning against a wall or fence to maintain balance, lethargy, and the inability to rise. While there is no cure, the clinical signs of the disease may be treatable.


Recently, the State Veterinarian’s office has received a high volume of calls with questions regarding equine strangles. In Colorado, equine strangles is not a reportable disease, and therefore it is not a disease that the State Veterinarian’s office will issue state quarantines for affected facilities or horses. While it is recommended for an infected barn to limit movement, restrictions with equine strangles are managed by the barn and the attending veterinarian.

Strangles is a contagious disease of horses of all ages but it is more commonly seen in young horses, usually less than 2 years of age. Foals are usually not susceptible until the antibodies that they receive from the mare decline which is usually around 4 months of age but it can be very variable. Commonly, once a horse has gone through the infection, they become immune to developing clinical signs again or the disease is not as severe the next time it develops in their system.

Using common sources of water, feed bunks and housing will allow transmission of the bacteria from horse to horse. Horses that are spread out in pastures or large exercise areas in which they can move and graze will not share the infection as readily.

In instances where accredited veterinarians have questions, we are happy to assist in developing plans for biosecurity and herd management to attempt to minimize the impact of an outbreak and maintain continuity of business for equine facilities. ❖