Brucellosis is a highly contagious zoonosis caused by ingestion of unpasteurized milk or undercooked meat from infected animals, or close contact with their secretions. It is also known as undulant fever, Malta fever, and Mediterranean fever.The bacteria causing this disease, Brucella, are small, Gram-negative, nonmotile, nonspore-forming, rod-shaped (coccobacilli) bacteria. They function as facultative intracellular parasites, causing chronic disease, which usually persists for life. Four species infect humans: B. abortus, B. canis, B. melitensis, and B. suis. B. abortus is less virulent than B. melitensis and is primarily a disease of cattle. B. canis affects dogs. B. melitensis is the most virulent and invasive species; it usually infects goats and occasionally sheep. B. suis is of intermediate virulence and chiefly infects pigs. Symptoms include profuse sweating and joint and muscle pain. Brucellosis has been recognized in animals and humans since the early 20th century. Signs and symptoms
The symptoms are like those associated with many other febrile diseases, but with emphasis on muscular pain and night sweats. The duration of the disease can vary from a few weeks to many months or even years. In the first stage of the disease, bacteremia occurs and leads to the classic triad of undulant fevers, sweating (often with characteristic foul, moldy smell sometimes likened to wet hay), and migratory arthralgia and myalgia (joint and muscle pain).
Brucella and all other remaining biological weapons in the U.S. arsenal were destroyed in 1971–72 when the American offensive biological warfare  program was discontinued by order of President Richard Nixon.The experimental American bacteriological warfare program focused on three agents of the Brucella group:
Porcine brucellosis (agent US)
Bovine brucellosis (agent AA)
Caprine brucellosis (agent AM)Agent US was in advanced development by the end of World War II. When the United States Air Force (USAF) wanted a biological warfare capability, the Chemical Corps offered Agent US in the M114 bomblet, based on the four-pound bursting bomblet developed for spreading anthrax during World War II. Though the capability was developed, operational testing indicated the weapon was less than desirable, and the USAF designed it as an interim capability until it could eventually be replaced by a more effective biological weapon.The main drawback of using the M114 with Agent US was that it acted mainly as an incapacitating agent, whereas the USAF administration wanted weapons that were deadly. The stability of M114 in storage was too low to allow for storing it at forward air bases, and the logistical requirements to neutralize a target were far higher than was originally planned. Ultimately, this would have required too much logistical support to be practical in the field.Agents US and AA had a median infective dose of 500 organisms/person, and for Agent AM it was 300 organisms/person. The incubation time was believed to be about 2 weeks, with a duration of infection of several months.