Brucella

Zoonotic infections have raised the profile of many pathogenic bacteria of animals, allowing for in-depth research into pathogenesis. For Brucella spp., this livestock–human association goes back to at least Roman times and likely far earlier. The pathogenesis and basic biology of this genus are largely known from three species and their natural hosts, Brucella abortus in cattle, B. melitensis in goats, and Brucella suis in pigs. This chapter focuses on these three species, but it should be noted that much remains unknown about host–microbe interactions in Brucella, particularly etiology and host response in recently discovered species. It describes the characteristics, source of infection, types of disease, pathologic changes, virulence factors, pathogenesis, and immunity of Brucella. It presents the essential step for disease control and prevention and regulation of virulence in Brucella as well as gaps in understanding its mechanisms of pathogenesis.