Yellowstone Park bison herd a highly contagious zoonosis caused by ingestion of unpasteurized milk or undercooked meat from infected animals, or close contact with their secretions. Brucellosis occurs naturally in the Yellowstone Bison Herd and the normal winter migrations of bison outside the park have raised concerns that Brucellosis infected Bison may infect cattle. The United States government has programs to eradicate brucellosis in domestic livestock. Since 1934, an estimated $3.5 billion in federal, state, and private funds has been spent on brucellosis eradication in domestic livestock. Over the years, the National Park Service and states bordering the park have implemented various plans to
Brucellosis (goats and sheep), "B. ovis" (sheep), and "B. suis" (caribou and pigs). "Brucella" species have also been isolated from several marine mammal species (cetaceans and pinnipeds). "B. abortus" is the principal cause of brucellosis in cattle. The bacteria are shed from an infected animal at or around the time of calving or abortion. Once exposed, the likelihood of an animal becoming infected is variable, depending on age, pregnancy status, and other intrinsic factors of the animal, as well as the number of bacteria to which the animal was exposed. The most common clinical signs of cattle infected with "B. abortus"