A Case of Scrub Typhus in Summer Presenting as Atypical Pneumonia

Scrub typhus usually occurs in October and November in Korea. Its typical clinical manifestations are fever, rash, eschar, and lymphadenopathies. Pneumonitis may occur, however, it occurs as a complication at the late phase of scrub typhus, when it is inappropriately treated. We encountered a case of pneumonitis that was an initial manifestation of scrub typhus which was confirmed by rickettsial culture, positive seroconversion, and polymerase chain reaction. The case was a 16year-old high school adolescent who presented with fever and headache that lasted for 1 day in July, 2007. He denied of any outdoor activities. A chest radiograph showed patchy infiltrates in the left lower lung, which improved with the administration of cefotaxime and azithromycin for empirical treatment of community-acquired pneumonia. Blood taken on the second febrile day showed a positive culture for Orientia tsutsugamushi and was also positive for O. tsutsugamushi DNA polymerase chain reaction. Immunofluorescent antibody ( IFA) test for O. tsutsugamushi showed that the initial antibody was negative, but convalescent serum tested positive with an antibody titer of 1: 80. IFA for Coxiella burnetii showed false positive results; the initial IgM and IgG titers were 1: 128 and 1: 256, respectively, and the IgM and IgG titers in convalescent serum were 1: 128 and 1: 128, respectively.