Queensland tick typhus
Patients develop a febrile syndrome with headache and myalgias 1-11 days (mean 5 days) after a tick bite. A diffuse rash follows accompanied by an eschar at the site of the tick bite in one-half to two-thirds of cases. Occasionally, QTT may be "spotless." Lymphadenopathy adjacent to the bite may be present 50%-75% of the time. Hepatomegaly and splenomegaly may be observed as well. Laboratory abnormalities include thrombocytopenia, hyponatremia, renal insufficiency, and transaminitis. At least one fatality has been reported. Complications such as renal failure, pneumonia, and purpura fulminans may rarely occur.
Males are more often infected than females, more patients are affected in the winter and spring months, and up to 90% of patients may give a history of a tick bite.
A77.3 – Spotted fever due to Rickettsia australis
68981009 – Queensland tick typhus
Differential Diagnosis & Pitfalls
The agents that cause Rocky Mountain spotted fever, African tick bite fever, and Mediterranean spotted fever do not exist in Australia.
Scrub typhus overlaps with QTT geographically, but scrub typhus is generally more severe (eg, encephalopathy, organ failure).