Isolation of a New Orientia tsutsugamushi Serotype

Abstract

Orientia tsutsugamushi, the etiological agent of scrub typhus, is an antigenically diverse organism and many serologically distinct strains have been identified. The 56kDa protein of O. tsutsugamushi, a major protein in the outer membrane, has been thought to be responsible for this antigenic variability. A strain of O. tsutsugamushi isolated in Korea cross-reacted with both Gilliam strain-specific and Karp strain-specific monoclonal antibodies. When its 56kDa protein gene was cloned and analyzed, its sequence showed variation especially between 1, 200 and 1, 250bp, showing that this isolate is a new O. tsutsugamushi strain.