glanders, highly contagious disease of horses, mules, and donkeys, caused by the bacterium Actinobacillus mallei. Although it can be transmitted to humans, it is limited almost exclusively to handlers of equine animals. The disease causes death in infected animals or humans. Glanders has been virtually eradicated in the United States, Canada, and Great Britain but still occurs in Asia and South America. There are three primary sites of infection: the nasal membranes and upper respiratory tract; the lungs; and the skin. The bacteria cause lumps or nodules to form in the affected area. The nodules enlarge, form ulcers, and release pus that spreads the germs to other parts of the body. In the cutaneous form of the disease, craterlike ulcers form on the skin along the course of the lymph vessels of the extremities; this form of glanders is commonly called farcy. There is no effective treatment for glanders and the infected animal must be destroyed to prevent the spread of the disease.