Brucellosis Brucellosis Brucellosis is a highly contagious zoonosis caused by ingestion of unpasteurized milk or undercooked meat from infected animals, or close contact with their secretions. It is also known as undulant fever, Malta fever and Mediterranean fever. "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 humans: "B. abortus", "B. canis", "B. melitensis", and "B. suis". "B. abortus" is less virulent than "B. melitensis" and is primarily a disease of cattle. "B. canis" affects dogs. "B. melitensis" is the most virulent and
Brucellosis a "calfhood" vaccination. Most cattle receive a tattoo in one of their ears, serving as proof of their vaccination status. This tattoo also includes the last digit of the year they were born. The first state–federal cooperative efforts towards eradication of brucellosis caused by "Brucella abortus" in the U.S. began in 1934. Brucellosis was originally imported to North America with non-native domestic cattle ("Bos taurus"), which transmitted the disease to wild bison ("Bison bison") and elk ("Cervus canadensis"). No records exist of brucellosis in ungulates native to America until the early 19th century. Antibiotics such as tetracyclines, rifampin, and the