Burkholderia mallei bacteria, coloured transmission electron micrograph (TEM). B. mallei is the cause of glanders, an infectious disease primarily affecting horses. Human infection, although not seen in the United States since 1945, has occurred rarely and sporadically among laboratory workers and those in direct and prolonged contact with infected, domestic animals. It is a potential agent for biological warfare and biological terrorism. The types of infection include localized, pus-forming cutaneous infections, pulmonary infections, and bloodstream infections. Magnification: x10,500 when printed 10cm high.