Rickettsioses in Australia.

Australia, an island continent in the southern hemisphere, has a range of rickettsial diseases that include typhus group rickettsiae (Rickettsia typhi), spotted fever group rickettsiae (R. australis, R. honei), scrub typhus group rickettsiae (R. tsutsugamushi), and Q fever (C. burnetii). Our knowledge of Australian rickettsiae is expanding with the recognition of an expanded range of R. honei (Flinders Island spotted fever) to Tasmania and southeastern mainland Australia (not just on Flinders Island), and the detection of a new SFG species (or subspecies), tentatively named "R. marmionii" in the eastern half of Australia. This rickettsia causes both acute disease (7 cases, recognized so far) and is also associated (as a "R. marmionii" bacteriaemia) with patients having a chronic illness. The significance of the latter is under investigation. It may be a marker of autoimmune disease or chronic fatigue in some patients.