FIELD SURVEY ON TSUTSUGAMUSHI DISEASE IN TAIWAN IN CONNECTION WITH THE INCREASE OF TSUTSUGAMUSHI DISEASE CASES IN RECENT JAPAN

Research Project

Project/Area Number	62043065
Research Category	Grant-in-Aid for Overseas Scientific Research
Allocation Type	Single-year Grants
Section	調査総括
Research Institution	UNIVERSITY OF THE RYUKYUS
Principal Investigator	OTSURU Masamitsu PROFESSOR EMERITUS, VISITING PROFESSOR, SCHOOL OF MEDICINE, UNIVERSITY OF THE RYUKYUS, 医学部・名誉教授, 客員教授 (60018281)
Co-Investigator(Kenkyū-buntansha)	FUJII Tamotsu INSTRUCTOR, SCHOOL OF MEDICINE, UNIVERSITY OF THE RYUKYUS, 医学部, 助手 (10181314) HASEGAWA Hideo ASSOCIATE PROFESSOR, SCHOOL OF MEDICINE, UNIVERSITY OF THE RYUKYUS, 医学部, 助教授 (00126442) SATO Yoshiya PROFESSOR, SCHOOL OF MEDICINE, UNIVERSITY OF THE RYUKYUS, 医学部, 教授 (60092699)
Project Period (FY)	1986 – 1987
Project Status	Completed (Fiscal Year 1987)
Budget Amount *help	¥1,300,000 (Direct Cost: ¥1,300,000) Fiscal Year 1987: ¥1,300,000 (Direct Cost: ¥1,300,000)
Keywords	Tsutsugamushi Disease / Taiwan / Epidemiology / Trombiculid mites / Wild rodents / リケッチア
Research Abstract	An epidemiological field research on tsutsugamushi disease in Taiwan was carried out during the period from 24 July to 17 August, 1986. The data and materials collected were brought back to Japan and analysed in 1987. From the statistical data, it was known that about 100 cases of tsutsugamushi disease were recorded yearly in Taiwan. Most of the patients were farmers and military soldiers on Peng-hu Isls. (Pescador Isls.) and in Tai-tung Prefecture, and most of the cases occurred in summer, By the field surveys, it was also demonstrated that the patients had acquired the infection in bushes aroud their residing sites and cultivated fields. The reactiveities of 40 patients' sera collected in the present survey to the prototype strains of Gilliam, Karp and Kato were examined by the indirect fluorescent antibody test and the immunoperoxidase test, and it was shown that the sera reacted strongly with Gilliam and Karp strains. In immunoblotting assay, these patients' sera reacted clearly with 45-65K polypeptides of all prototypes which were considered to be a strain specific antigen. The relatively low specificity in the reactivities to the prototype strains suggests that the rickettsiae in Taiwan might have antigenic properties distinctive from the prototypes. A total of 58 mammals comprising of 31 Suncus murinus, 8 Mus muculus, 4 Rattus losea and 15 Bandicota indica were trapped on Peng-hu Isls, and in Tai-tung and Ping-tung Prefectures, and 7,395 trombiculid mites were collected from them. Leptotrombidium (L.) deliense was the predominant species occupying more than 90% of mites popolations collected in every area surveyed. No other species of the subgenus Leptotrombidium was detected suggesting that L.(L.) deliense is the main vector of tsutsugamushi disease in these areas. Rickttiae were isolated from 6 rodents, and their polypeptide composition and antigenic components are now being examined in detail.