The Rickettsia are Gram-negative, obligate intracellular bacteria that infect mammals and arthropods. Genera include Rickettsia, Rochalimaea, Coxiella, Orientia. These organisms are small, pleomorphic coccobacilli about 2 µm in length. Their structure is typical of Gram-negative bacteria. Rickettsia replicate in the cytoplasm and nucleus of their host cell; Coxiella replicate only in the phagolysosome.
| Rickettsial infection | Organism | Transmitted by | Symptoms |
|---|---|---|---|
| Flinders Island Spotted Fever | Rickettsia honei | Ticks | Fever, headache, rash etc. Flinders Is, South Australia, Tasmania. See FISF. |
| Scrub Typhus | Orientia tsutsugamushi | Mites (larval mites usually found on small mammals such as rats) | Fever, headache, rash etc. It is considered endemic in coastal northern Australia, throughout Asia and India. |
| Murine Typhus | Rickettsia typhi | Fleas (mainly rat flea ) | Fever, headache, rash etc. Rare in Australia. |
| Q Fever | Coxiella burnetii | Animal fluids (meat, milk etc) - inhalation or ingestion of. Theoretical risk from ticks. | Fever, headache etc. but no rash. High risk in abattoir workers. See www.qfever.org. |
^ Geographic distribution of rickettsial diseases in Australia. Dimitri M. Odorico,* Stephen R. Graves,† Bart Currie,‡ Julian Catmull,*
Zoltan Nack,† Sharon Ellis,† Ling Wang,† and David J. Miller*
*James Cook University, Townsville, Queensland, Australia; †The Geelong
Hospital, Geelong, Victoria, Australia; and ‡Royal Darwin Hospital, Casuarina,
Northern Territory, Australia