Orientia tsutsugamushi, the agent of scrub typhus, is transmitted by larval mites or chiggers in environments with heavy scrub vegetation.
Disease occurs during the wet season. It is endemic in eastern and southern Asia, northern Australia, and the Pacific islands.
The classic case description includes signs rarely seen in indigenous pts: an eschar at the site of chigger feeding, regional lymphadenopathy, and maculopapular rash. Westerners commonly do not present with all three findings. Severe cases include encephalitis and interstitial pneumonia.
Scrub typhus can be diagnosed by serologic assays (IFA, indirect immunoperoxidase, and enzyme immunoassays); PCR analysis of eschars and blood is also effective.