ABSTRACT
Introduction .................................................................................................................................... 627 Genus Anaplasma .......................................................................................................................... 628 Genus Bartonella ........................................................................................................................... 629 Genus Borrelia ............................................................................................................................... 630 Genus Brucella .............................................................................................................................. 632 Genus Coxiella ............................................................................................................................... 633 Genus Francisella .......................................................................................................................... 635 Genus Pasteurella .......................................................................................................................... 636 Conclusions .................................................................................................................................... 637 References ...................................................................................................................................... 638
Zoonotic bacteria can be transmitted between humans and other animal species. More than 200 bacterial and viral zoonotic pathogens have been recognized, which include — but are not limited to — many arthropod-, primate-, and rodent-borne agents. Lately, zoonotic bacteria have assumed additional importance because more than two-thirds of all emerging pathogens during the past three decades are zoonotic in origin. These pathogens are represented by diverse taxa and are not restricted to any particular class or group of bacteria. Zoonotic pathogens maintain either an ongoing reservoir life cycle in animals or arthropod vectors without maintaining a permanent life cycle in humans; or in some cases, they have jumped the species barrier and now maintain a permanent life cycle in humans and may not need the animal reservoir. Figure 39.1 shows the interplay of potential zoonotic pathogens with animal reservoirs and human host in the development of zoonotic diseases. Zoonotic pathogens’ ability to colonize human organs and their disease-causing capability vary considerably. Because these pathogens have evolved to live in multiple hosts, including both vertebrates and invertebrates, to maintain their enzootic lifestyle, their genomes have evolved to help them sustain life in different host environments. Some of them have a diminished ability to synthesize essential proteins because they can be acquired from the host. However, many of them retain their ability to make all the specic cofactors and vitamins to sustain efcient growth. These pathogens probably exploit receptors that are common in multiple hosts to colonize and/or gain entry into a human host. Several groups of pathogens with representatives that can cause zoonotic disease are described in their own chapters in this book. This chapter briey discusses the pathogens of the following zoonotic genera: Anaplasma, Bartonella, Borrelia, Brucella, Coxiella, Francisella, and Pasteurella.
