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

1986年7月24日至8月17日，对台湾地区的恙虫病进行了流行病学现场调查。收集的资料和资料是1987年带回日本进行分析的。从统计资料可知，台湾每年约有100例恙虫病病例。患者多为澎湖岛的农民和军人。(Pescado ISLS)而在台东县，多数病例发生在夏季，现场调查也证实患者是在居住地及耕种地周围的灌木丛中感染的。用间接荧光抗体试验和免疫过氧化物酶试验检测了本次调查收集的40份患者血清对Gilliam、Karp和Kato三株原型株的反应性，结果表明该血清与Gilliam株和Karp株具有较强的反应性。在免疫印迹试验中，这些患者的血清与所有原型的45-65K多肽反应明显，这些多肽被认为是毒株特异性抗原。台湾立克次体可能具有不同于原型的抗原性。在澎湖县、台东县和屏东县共捕获58只哺乳动物，包括31只森鼠、8只小鼠、4只黄鼠和15只印度斑潜蝇。纤毛菌Leptotrombidium(L.)在所有调查地区采集的尘螨种群中，以Deliense为优势种，占总数的90%以上。没有发现Leptotrombidium亚属的其他种，表明L.(L.)Deliense是这些地区恙虫病的主要传播媒介。从6只啮齿动物中分离到立克次体，目前正在对其多肽组成和抗原成分进行详细研究。

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.