United States raw milk debate prior to symptom onset." Milk collected or stored in unsanitary conditions may harbor a host of disease-causing organisms (pathogens), such as "tuberculosis" (Mycobacterium bovis), the bacteria "Campylobacter" (Campylobacteriosis), "Escherichia" E. coli O157:H7), "Listeria" (Listeriosis), "Salmonella" (Salmonellosis), "Yersinia" (Yersinia enterocolitica), and "Brucella" (Brucellosis). Pasteurization consistently removes all of these pathogens, though they can be reintroduced if the product is handled carelessly. Thus dairy farms that pasteurize their milk can have unsanitary facilities without the attendant outbreaks of disease that would occur if a raw milk dairy kept its herds in similar unsanitary conditions. People with weakened immune systems, such as elderly,
Brucellosis have reported persistent PCR positivity after clinically successful treatment, fuelling the controversy about the existence of prolonged chronic brucellosis. Other laboratory findings include normal peripheral white cell count, and occasional leucopenia with relative lymphocytosis. The serum biochemical profiles are commonly normal. According to a study published in 2002, an estimated 10–13% of farm animals are infected with "Brucella" species. Annual losses from the disease were calculated at around 60 million dollars. Since 1932, government agencies have undertaken efforts to contain the disease. Currently, all cattle of ages 3–8 months must receive the "Brucella abortus" strain 19 vaccine. Australia is free