Brucellosis, Bang's disease, Crimean fever, Gibraltar fever, Malta fever, Maltese fever, Mediterranean fever, rock fever, or undulant fever, is a highly contagious zoonosis caused by ingestion of unpasteurized milk or undercooked meat from infected animals or close contact with their secretions. Brucella species are small, Gram-negative, nonmotile, nonspore-forming, rod-shaped (coccobacilli) bacteria. They function as facultative intracellular parasites, causing chronic disease, which usually persists for life. Four species infect human: B. melitensis, B. abortus, B. suis, and B. canis. B. melitensis is the most virulent and invasive species; it usually infects goats and occasionally sheep. B. abortus is less virulent and is primarily a disease of cattle. B. suis is of intermediate virulence and chiefly infects pig. B. canis resides in the dogs. Symptoms include profuse sweating and joint and muscle pain.