[Analysis of clinical severity of tsutsugamushi disease according to the serotype of pathogenic rickettsia].

We compared the severity of clinical symptoms and laboratory test results of tsutsugamushi disease patients in Oita Prefecture according to the serotype of infected R. tsutsugamushi. Of the 45 patients, except one with the Karp-type, who were suffering in Oita Prefecture between 1992 and 1994, 20 were the Irie-type and 24 were the Hirano-type. There was no apparent difference with regard to clinical symptoms between the two groups of patients. Laboratory tests showed that CRP increased almost equally in the two groups. The ESR level was slightly higher in the Irie-type patients than in the Hirano-type, but did not differ significantly between the two groups. Both leukocyte count in the acute stage and platelet count decreased in the Hirano-type, as compared with those of normal ranges in the Irie-type. GPT values elevated in proportion to the day of illness in the acute stage. This trend continued after the initiation of specific chemotherapy in the Hirano-type. The median GOT, GPT and LDH values were 71, 65 and 709 IU/l for the patients in the Hirano-type, as compared with 37, 36.5 and 546.5 for the patients in the Irie-type, respectively. Above results show that the Hirano-type rickettsiae produces a more severe illness than the Irie-type ricketsia. Platelet count had a significant correlation with ESR, suggesting the pathophysiologic changes leading to disseminated intravascular coagulation, a symptom of severe tsutsugamushi disease. There may be common causes in leukopenia and thrombopenia, as being suggested by the significant correlation between leukocyte count and platelet count.