Brucellosis is a contagious disease of livestock with significant economic impact. The disease is caused by various bacteria of the family Brucella, which tend to infect specific animal species. However, most Brucella species can infect other animal species as well. Brucellosis in cattle (B. abortus) in sheep and goats (B. melitensis) and in swine (B. suis) are diseases listed in the World Organisation for Animal Health (WOAH) Terrestrial Animal Health Code and must be reported to the WOAH (Terrestrial Animal Health Code). Brucellosis is a highly infectious zoonosis for humans. The spread to humans most often occurs by drinking raw milk from infected animals. It causes severe debilitating diseases in people. Veterinarians, farmers, and abattoir workers are vulnerable to infection as they handle infected animals and aborted fetuses or placentae. Human brucellosis is best prevented by controlling the infection in animals. Pasteurisation of milk from infected animals is an important way to reduce infection in humans.