Richard T. Ellison III, MD reviewing Weitzel T et al. N Engl J Med 2016 Sep 8. Walker DH. N Engl J Med 2016 Sep 8.

An Asian infection has appeared in South America.

Scrub typhus, caused by Orientia tsutsugamushi, is an endemic zoonotic infection transmitted by the larvae (“chiggers”) of trombiculid mites in what has been termed the tsutsugamushi triangle that extends from eastern Russia west to Pakistan and south to northern Australia. The primary reservoir is the vector, due to transstadial and transovarian passage of the rickettsia-like microorganism. Recently, unexpected cases of scrub typhus due to related Orientia species have been identified, one in the Middle East and the second in Chile. Now investigators have identified three cases of O. tsutsugamushi on Chiloé island in Chile.

Between January 2015 and February 2016, three individuals on the island developed acute illness characterized by high fever, chills, night sweats, headache, myalgias, maculopapular rash, and single necrotic eschars on the leg or abdomen. All three patients had been collecting or handling firewood, a known risk factor for chigger bites, and all responded to treatment with doxycycline. The first two patients were confirmed to have infection with O. tsutsugamushi on the basis of both seroconversion and polymerase chain reaction analysis of eschar samples along with negative tests for other organisms in the order Rickettsiales. The third patient had two high single-titer serologic tests for O. tsutsugamushi with negative tests for related organisms.

CITATION(S):

Weitzel T et al. Endemic scrub typhus in South America. N Engl J Med 2016 Sep 8; 375:954. 

Walker DH.Scrub typhus — scientific neglect, ever-widening impact. N Engl J Med 2016 Sep 8; 375:913.

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