Development of a diagnostic system for definitive hosts of taeniid cestodes and an epizootiological survey for echinococcosis in urban area

多房棘球蚴是一种在北海道流行的人畜共患寄生虫。该寄生虫的最终宿主为狐狸和狗等食肉动物，中间宿主为啮齿动物。人类因误食毒素而感染；寄生虫卵。近十年来，北海道地区狐狸棘球蚴病患病率约为40%，宠物犬棘球蚴病患病率为0.3-0.7%。为应对日益恶化的情况，日本自2004年起实施犬棘球蚴病报告制度。本研究旨在通过结合特异性DNA检测，改进最终宿主的诊断系统，并对札幌及其郊区寄生虫的城市生命周期和感染风险进行调查。在诊断、系统研究中，对多房绦虫的特异引物PCR和其他绦虫的PCR- rflp，对在粪卵检查中发现但在该科中形态难以区分的绦虫卵进行了检测。此外，通过检查脱虫后的粪便，证明了在卵未随宿主粪便排出的孕前期进行DNA诊断是可行的。此外，在日本和其他国家收集的样本显示，一种正在开发的粪原抗原检测试剂盒具有高可靠性，可纳入诊断系统。在评价过程中，在日本首次发现了一种多房猫粪卵。在城市生命周期调查中，发现札幌和小樽地区的狐狸患病率较高。狐狸在选择巢穴时表现出地理偏好。因此，可以估计城市地区感染棘球蚴的危险区域——狐的潜在家居范围。

Echinococcus multilocularis is a zoonotic parasite endemic in Hokkaido. The definitive host of the parasite carnivore animal such as fox and dog, and the intermediate host is rodent. Humans get infection by accidentally ingestin; the parasite eggs. The prevalence in foxes in Hokkaido was about 40% in the last decade and that in pet dogs is 0.3-0.7% In response to a deteriorating situation, reporting system for canine echinococcosis has been enforced since 2004 in Japan. This study has aimed to improve a diagnostic system for the definitive hosts by incorporating specific DNA detection and t, investigate an urban life cycle of the parasite and risk for infection in Sapporo and its suburbs. In research for diagnosti, system, PCR with specific primers for E. multilocularis and PCR-RFLP for other taeniid cestodes were developed for the egg of taeniid cestodes that were found in fecal egg examination but morphologically indistinguishable among the family. Moreover DNA diagnosis in prepatent period in which eggs are not excreted in host feces was shown to be feasible by examining th, post-dewormed feces. In addition, high reliability of a developing coproantigen detection kit which can be incorporated i the diagnostic system was shown using the samples collected in Japan and other countries. During the evaluation, a cat excretin E. multilocularis eggs were found at first in Japan. In investigation on an urban life cycle, high prevalence was found i foxes inhabiting in Sapporo and Otaru. Foxes showed geographical preference for selecting their den sites. Therefore, potentia home range of infected foxes, thus a risk area for Echinococcus infection in the urban area could be estimated.