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Brucellosis, a bacterial disease caused by members of the genus Brucella, is an important zoonosis and a significant cause of reproductive losses in animals. Brucellosis is usually caused by Brucella abortus in cattle, B. melitensis or B. ovis in small ruminants, B. suis in pigs and B. canis in dogs. Abortions, placentitis, epididymitis and orchitis are the most common consequences, although other syndromes are also reported. The main impact is economic; deaths are rare except in the fetus and neonate. Some Brucella species are also maintained in wildlife populations. Wildlife reservoirs including feral pigs, bison, elk and European hares complicate eradication efforts for B. abortus and B. suis. Marine mammal isolates of Brucella have recently been recognized in many species of pinnipeds and cetaceans, and there are concerns that these organisms might have a detrimental impact on some species.

Most species of Brucella can infect animals other than their preferred hosts, when they come in close contact. B. abortus, B. melitensis, B. suis, B. canis and marine mammal Brucella species are human pathogens. In humans, brucellosis can be a serious, debilitating and sometimes chronic disease that may affect a variety of organs. Most cases are caused by occupational exposure to infected animals or the ingestion of unpasteurized dairy products. In the U.S., B. suis has been eliminated from commercial pigs and B. abortus has nearly been eradicated from domesticated ruminants. As a result, human brucellosis is rare. However, this disease remains a common and serious problem in some parts of the world. In addition, some species of Brucella could be used in a bioterrorist attack.

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Iowa State University



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