Rickettsial diseases can be broken down into three basic groups. The spotted fever group (SFG), the typhus group (TG) and the scrub typhus group (STG). All three groups cause disease and are represented in Australia.
Most of the rickettsia of the SFG are tick transmitted. In Australia we have a number of characterised members of this group.
Rickettsia australis, R. honei, R. honei subspecies marmionii, R. gravesii, R. argasii and R. felis (flea transmitted).
Although the TG has two members, Rickettsia typhi and R. prowazekii, only R. typhi is endemic in Australia. It is transmitted by the flea faeces.
Scrub Typhus Group
The Scrub Typhus group is made up of two rickettsial species, Orientia tsutsugamushi and O. chuto. These agents are mite transmitted.