Epidemiological survey of Orientia tsutsugamushi distribution in field rodents in Saitama Prefecture, Japan, and discovery of a new type.

There are various antigenic variants of Orientia tsutsugamushi which are distinguished by immunological and molecular genetic methods targeted at the antigenic diversity of 56-kDa type-specific antigen proteins. The present study was performed to analyze 15 strains successfully isolated from rodents in Saitama Prefecture, Japan, by 56-kDa gene sequence homologies, reactivities with type-specific monoclonal antibodies and polymerase chain reaction (PCR) using type-specific primer-pairs. We demonstrated the presence of a new type of O. tsutsugamushi among the isolates. This new type, designated as the Saitama type, was located in the branch of Karp type in the phylogenetic tree based on 56-kDa gene sequences, but distant from the known Karp types, such as Karp, JP-1 and JP-2, showing less than 90% homology. Strains of this type could not be distinguished by immunological methods from Karp type strains, but a new primer-pair for PCR which specifically amplifies the DNA of this new type strain was designed. This primer-pair may serve to find this strain type in future studies.

Isolation of Orientia tsutsugamushi from Leptotrombidium fuji and its characterization.

In our attempts to isolate Orientia tsutsugamushi from trombiculid mites, a strain was successfully isolated from Leptotrombidium fuji collected in Aichi Prefecture, Japan. This is the first case of isolation of O. tsutsugamushi from L. fuji. A phylogenetic analysis based on the base-sequence homology of the 56-kDa type-specific antigen-gene indicated that the strain is a new type which is not closely related to any strains analyzed previously. Three strains isolated from Leptotrombidium pallidum harvested at the same area were identified as being closely related to the JP-2 type (subtype-2 of Karp type in Japan) by phylogenetic analysis.

Isolation of Orientia tsutsugamushi from patients in Shikoku and finding of a strain which grows preferentially at low temperatures.

Three strains of Orientia tsutsugamushi were isolated from patients in Anan City, Tokushima Prefecture. The strains were identified as Karp type by analyses of reactivities with type-specific monoclonal antibodies. One strain, Okazaki, was isolated in L cells cultivated at 31 C, but not in cells at 36 C or in mice. This strain showed better growth at 31 C than 36 C. This is the first report of an O. tsutsugamushi strain which grows preferentially at low temperatures.

Complete necrotization of hepatocellular carcinoma by chemotherapy and subsequent intravascular coagulation: a case report.

A 45-year-old man with hepatocellular carcinoma who developed intravascular coagulation following complete tumor regression by chemotherapy is described. After 2 doses of 10 mg of Mitomycin C given into the hepatic artery at the time of selective angiography, and 16 intravenous doses of 5-fluorouracil and Mitomycin C, 2 doses per week, subjective symptoms and hepatomegaly disappeared. Alpha-fetoprotein became negative and a remarkable change in tumor size and vasculature was noted in the arteriogram. Three months after chemotherapy, the patient developed thrombocytopenia, intravascular hemolysis, and acute renal failure. Autopsy disclosed a 8 X 7 X 5 cm solitary, encapsulated hepatocellular carcinoma in the right lobe. The tumor was surrounded by a thick capsule and completely necrotized. Neither intrahepatic invasion nor extrahepatic metastasis was observed. In the kidney, generalized fibrin thrombi were seen in the afferent arterioles of glomeruli as accounted for by intravascular coagulation.