11 Pages

Rocky Mountain Spotted Fever

WithJ. Stephen Dumler

This chapter identifies animal diseases that are host specific and reviews the effects of various human diseases on animals. It also identifies history, etiologic, human Infection, diagnosis, public health aspects and therapeutic aspects of each disease important to epidemiology and prevention. Within the boundaries of the United States, few zoonotic diseases have stirred as much fear of ticks as has Rocky Mountain spotted fever (RMSF). The disease is caused by inoculation of the subject with tick saliva containing viable Rickettsia rickettsii. The etiologic agent of RMSF, R. rickettsii, is the prototype of the spotted fever serologic group of rickettsiae in the family Rickettsiaceae. The natural life cycle of R. rickettsii involves both ticks and mammals and may be propagated by vertical transmission in reservoir ticks and horizontal tick-to-mammal-to-tick transmission. The pathogenesis in humans is identical to that described for canines. R. rickettsii parasitize endothelial cells and disseminate to infect and damage endothelium in all tissues.