Brucellosis is caused by bacteria of the genus Brucella and is characterized by abortion, retained placenta, and to a lesser extent, orchitis and infection of the accessory sex glands in males. The disease occurs in most countries. It primarily affects cattle Brucellosis in Cattle Infection with Brucella abortus can cause abortion, birth of stillborn or weak calves, retained placenta, and reduced milk production. Infected cattle usually abort only once but can... read more , buffalo, bison, pigs Brucellosis in Pigs Swine brucellosis is a zoonotic disease caused by infection with Brucella suis. Infection may cause abortion, infertility, lameness, orchitis, and swelling of male accessory sex glands... read more , sheep Brucellosis in Sheep Brucella melitensis infection in certain breeds of sheep causes clinical signs of disease similar to those in goats. However, B ovis produces a disease unique to sheep, in which... read more , goats, dogs Brucellosis in Dogs , elk, and occasionally horses Brucellosis in Horses Horses can be infected with Brucella abortus or B suis. Suppurative bursitis, most commonly recognized as fistulous withers or poll evil (bursitis) is the most common condition... read more . The disease in humans, referred to as undulant fever, is a serious public health problem, especially when caused by B melitensis.