Brucellosis, also called Bang's disease, Gibraltar fever, Malta fever, Maltese fever, Mediterranean fever, rock fever, or undulant fever, is a highly contagious zoonosis caused by ingestion of unsterilized milk or meat from infected animals, or close contact with their secretions. Transmission from human to human, for example through sexual contact or from mother to child, is exceedingly rare, but possible. Brucella spp. are small, Gram-negative, non-motile, non-spore-forming rods, which function as facultative intracellular parasites that cause chronic disease, which usually persists for life. Symptoms include profuse sweating and joint and muscle pain. Brucellosis has been recognized in animals including humans since the 19th century.