Glanders is an infection caused by Burkholderia mallei, a gram-negative bacillus. It is typically an equine disease. Glanders has been classified by the US Centers for Disease Control and Prevention (CDC) as a Category B bioterrorism agent due to the moderate ease with which it can be disseminated. If glanders were to be weaponized, the most likely method of dispersal would be by aerosol release.

Infection can be localized to the skin (chronic glanders) or mucous membranes (acute localized glanders) or manifest in the pulmonary system (acute pulmonary), and it may begin as or progress to a septicemic form.

The acute pulmonary form would most likely result following a bioterrorism attack. Without treatment, any of the acute forms have a mortality rate of up to 95%. The overall mortality rate of all forms, even with treatment, ranges from 20%-50%.

Whether acquired naturally (via inhalation or hematogenous spread) or as the result of a bioterrorist attack, pulmonary glanders has an incubation period of 10-14 days (but this may range from a few hours to days, depending on the inoculum) and presents with a sudden onset of flu-like symptoms accompanied by fever, rigors, sweats, cough, chest pain, myalgias, lacrimation, diarrhea, photophobia, cervical adenopathy, splenomegaly, and a widespread papular / pustular rash similar to smallpox. It quickly progresses to pneumonia and/or pulmonary abscesses. Chest x-ray is positive for miliary nodules, infiltrates, and/or lung abscesses.

In acute localized glanders, the bacteria enter through breaks in the skin or mucosal surfaces of the eyes, nose, and mouth and cause conjunctivitis and/or bloody discharge of mucus and pus from the nose. Acute forms are almost always fatal without treatment.

In chronic glanders, which has a delayed onset, cutaneous and intramuscular abscesses occur on the arms and legs. Splenic and liver abscesses may be seen as well as enlarged regional lymph nodes. Children may present with suppurative parotitis. On rare occasions, it progresses to meningitis.

Septicemic glanders is typically fatal within 7-10 days.

Glanders is transmitted through direct contact with an infected horse, donkey, or mule. The bacteria enter through the skin or the mucosal surfaces of the eyes, nose, and mouth or through inhalation. Person-to-person transmission is rare and is usually associated with melioidosis.

A prophylactic treatment for glanders is available.

Glanders is endemic in undeveloped countries in Asia, Africa, the Middle East, and South America. Since 1945, there have been only a handful of cases of glanders in the US (veterinarians and laboratory workers).

People at risk include veterinarians, equine pet owners, abattoir workers, workers in laboratories where the organism is being handled, and travelers to endemic areas.