Brucellosis is an infection caused by Brucella bacteria. There are several species of Brucella associated with specific animal hosts--Brucella abortus with cattle, Brucella melitensis with sheep and goats, Brucella canis with dogs, and Brucella suis with pigs. Brucellosis occurs most often in people who have contact with livestock or consume unpasteurized dairy products. The symptoms of brucellosis appear 1 to 3 weeks after exposure and include fever, sweats, malaise, headache, and back pain. Left untreated, brucellosis can result in infections in bones, joints, liver, kidney, spleen, or heart valves. Brucellosis is best controlled by eliminating transmission between domestic animals. Brucellosis eradication programs and pasteurization of commercial dairy products have greatly reduced the incidence of brucellosis in animals and people in the U.S. and other developed countries.