Prevention and control of brucellosis

What it is

Prevention is done in the animal before it is done in humans. It rests on vaccination of domestic livestock, serologic testing, quarantine of herds, and slaughter of infected animals, together with protection of slaughterhouse workers. Pasteurization of milk is very important for the prevention of transmission to humans. Two facts about the organism explain why those measures and not others. Brucella organisms can survive up to two days in milk at 8 C, up to three weeks in frozen meat, and up to three months in goat cheese - so the food still carries it long after the animal is gone. And boiling and pasteurizing the milk kill the bacterium - so the food can be made safe. Which animal to act on follows from which species is in question. Four species are pathogenic for humans: Brucella abortus, B. melitensis, B. suis and B. canis; and in general B. melitensis and B. suis are more virulent for humans than B. abortus or B. canis. Of the four, B. melitensis is the one most common in Oman. Their host preferences are set out as B. melitensis in sheep, goats and cattle with high pathogenic potential; B. abortus in cattle, moderate; B. suis in pigs, reindeer and hares, moderate; B. ovis in sheep, low; B. canis in dogs; B. neotomae in desert wood rats; B. pinnipedialis in seals, low; B. microti in common vales; B. ceti in cetaceans, low; and B. inopinata in a wild rodent in Australia, low.