The genus Rickettsia includes many species of bacteria associated with important and severe human or canine disease, including those in the spotted fever group and in the typhus group. The typhus group (TG) is composed of R. prowazekii and R. typhi, which are associated with lice and fleas, respectively; the spotted fever group (SFG), which includes more than 20 valid species, is mostly associated with ticks. Other species, such as R. bellii and R. canadensis, both associated with ticks, have been considered a distinct group sharing antigenic, genetic and ecological characters of both TG and SFG rickettsiae (Parola et al., 2005; Roux et al., 1997; Stothard et al., 1994).
Two important species are listed in more detail: Rocky Mountain spotted fever (RMSF), as a potentially fatal rickettsial disease of dogs and humans caused by R. rickettsii, and R. parkeri Infection as an emerging human pathogen, for which the dog has an important sentinel function.
- Parola P, Paddock CD, Raoult D: Tick-borne rickettsioses around the world: emerging diseases challenging old concepts. Clin Microbiol Rev. 2005, 18, 719-56
- Roux V, Rydkina E, Eremeeva M, et al.: Citrate synthase gene comparison, a new tool for phylogenetic analysis, and its application for the rickettsiae. Int J Syst Bacteriol. 1997, 47, 252-61
- Stothard DR, Clark JB, Fuerst PA: Ancestral divergence of Rickettsia bellii from the spotted fever and typhus groups of Rickettsia and antiquity of the genus Rickettsia. Int J Syst Bacteriol. 1994, 44, 798-804
For more information about these two pathogens see the following chapters: