[Serotype-specific amplification of Rickettsia tsutsugamushi DNA from clinical specimens by nested polymerase chain reaction].

Polymerase chain reaction (PCR) with nested primer pairs was used to diagnose Tsutsugamushi disease and identify the Rickettsia tsutsugamushi serotype. The primer pairs used for PCR were designed on the basis of the nucleotide sequence of the gene that encodes the 56-kDa antigen. Five serovariants, the Gilliam, Karp, Kato, Kawasaki, and Kuroki strains of Rickettsia tsutsugamushi were detected and identified by nested PCR. The serotypes of patients registered during 1990 to 1992 in Kanagawa Prefecture were identified by nested PCR. Sixty percentage of patients showed Kawasaki types, 20% Karp types, and 20% Kuroki types. This result suggested that the recent Tsutsugamushi disease were mostly caused by Kawasaki types in Kanagawa Prefecture.