Glanders in Horses: Reportable Bacterial Disease and Human Risk

Glanders is a contagious bacterial disease of horses, donkeys, and mules caused by Burkholderia mallei. It can affect the nose, lungs, skin, and lymphatic system. In many equids, the disease is severe and often fatal. It is also a zoonotic disease, which means people can become infected after contact with an affected horse, its body fluids, contaminated tack or buckets, or infectious droplets.

In the United States, glanders is considered a foreign animal disease concern and a nationally reportable disease. That matters because a horse with suspicious signs should not be treated like a routine respiratory case. Your vet may recommend immediate isolation, limited handling, and rapid communication with state or federal animal health officials while testing is arranged.

Glanders has been eradicated from many regions, including the United States, but it still occurs sporadically in some parts of Asia, Africa, the Middle East, and South America. Horses with recent import history, international travel, or contact with imported equids may raise more concern. Even so, only testing can confirm the diagnosis, because early signs can look like other equine infections.

Glanders is caused by the bacterium Burkholderia mallei. Horses usually become infected after exposure to contaminated feed or water, especially when nasal discharge from a carrier or infected equid gets into shared buckets, troughs, or feed areas. Infection can also happen through direct contact with infected secretions, contaminated equipment, or inhalation of infectious droplets.

The disease may appear in acute or chronic forms. Acute disease can cause fever, bloodstream infection, severe respiratory illness, and rapid decline. Chronic disease is more common in horses and may cause recurring nasal lesions, skin nodules, enlarged lymph vessels, weight loss, and long-term shedding that puts other animals at risk.

Risk goes up when horses are imported from or travel through countries where glanders is still reported, or when biosecurity is weak in mixed-equid settings. Because the organism can spread through contaminated materials and infected body fluids, shared tack, grooming tools, feed tubs, trailers, and handling equipment all matter. Your vet and animal health officials will focus heavily on exposure history if glanders is on the rule-out list.

Diagnosis starts with suspicion, not certainty. Clinical signs such as fever, thick nasal discharge, breathing difficulty, nasal ulcers, and farcy-like skin lesions can raise concern, but they are not enough to confirm glanders. Other infectious and inflammatory conditions can look similar, especially early on.

If your vet suspects glanders, they will usually recommend immediate isolation and official reporting while testing is coordinated. In the United States, suspected cases of diseases not known to exist here must be reported promptly to animal health authorities. That helps protect people, nearby horses, and the broader equine population.

Confirmation relies on laboratory testing. Depending on the situation, this may include serologic testing used in import screening, confirmatory testing through official laboratories, and in some cases bacterial culture or other specialized methods directed by regulatory veterinarians. USDA import protocols currently use a double antigen ELISA for screening and Western blot for confirmation in imported horses. Because glanders is a public health and regulatory issue, testing should be guided by your vet and the appropriate state or federal officials rather than arranged informally.

Prevention centers on biosecurity, import controls, and fast reporting. There is no vaccine for glanders, and treatment is not considered a reliable control strategy in horses. In countries free of the disease, the main goal is to keep it out through careful import testing, quarantine procedures, and prompt investigation of suspicious illness.

For horse facilities, practical prevention means avoiding shared water and feed containers when disease is a concern, cleaning and disinfecting equipment thoroughly, and separating any horse with fever, nasal discharge, skin nodules, or draining ulcers until your vet evaluates them. Imported horses and horses with recent international travel history deserve extra attention, especially if records are incomplete.

Human safety matters too. If glanders is suspected, wear gloves, mask or respirator, eye protection, and protective clothing when handling the horse, tissues, or drainage. Limit the number of people involved. Your vet may also advise specific disinfection steps for stalls, trailers, and tools. Confirmed positive animals are generally removed from the population through humane euthanasia under regulatory guidance, because elimination of infected animals is the cornerstone of control.

If your horse develops suspicious signs, do not move the horse to a show, sale, trail ride, or referral barn before speaking with your vet. Early isolation and reporting protect your horse community and reduce risk to people.