| Co-Investigator(Kenkyū-buntansha) |
IWAKI Takashi Tottori Univ., Dep. Med., Research Assistant, 医学部, 教務員 (70263473)
NONAKA Nariaki Hokkaido Univ., Grad. Schl. Vet. Med., Instructor, 大学院・獣医学研究科, 助手 (50281853)
OKU Yazaburo Hokkaido Univ., Grad. Schl. Vet. Med., Associate, 大学院・獣医学研究科, 助教授 (60133716)
MORISHIMA Yasuyuki National Inst. Inf. Dis., Dep. Parasitol., Resarch Associate, 寄生動物部, 研究員 (30342893)
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| Research Abstract |
Deworming trials to foxes, the natural definitive host of Echinococcus multilocularis, have been conducted in Koshimizu and Otaru, Hokkaido. Deworming baits used were 1) fishmeal sausage to which anthelmintic praziquantel tablet was put in and 2) machine-made boiled fish paste containing praziquantel powder. Those baits were distributed around fox breeding dens, along the road or at intersections of roads and windbreak forests. The prevalence in the fox population was evaluated by coproantigen and egg examination of fox feces and/or by autopsy of foxes captured at the study area. The prevalence of foxes in the bait distributed areas of Koshimizu and Otaru was significantly reduced.
In Sapporo, coproantigen and/or egg positive fox feces were found around fox breeding dens lacated in urban area. Since red-backed voles were captured near the dens, possible urban life cycle of E. multilocularis was suggested. In addition, high reliability of the coproantigen detection method in diagnosis was obtained by the comparison of necropsy results of foxes captured in Sapporo and its suburbs and the test results.
This study showed a potential role of the definitive hosts in transmission to humans, and a feasible countermeasure against those transmitter hosts.
In the survey of companion animals, feces of 1,650 dogs and 170 cats in Hokkaido were tested during 1997 to 2002, and 18 and 4 coproantigen and 6 and 6 egg positive dogs and cats were found, respectively. All of the egg positive dogs were coproantigen positive. All of the egg positive cats were presumably infected with Taenia taeniaeformis. Strikingly, in Dec. 2002, the first egg excreting case was found among indoor keeping dogs in Sapporo. Feces of 64 dogs and 2 cats in the region other than Hokkaido were tested and 2 coproantigen and egg positive dogs were found. One of the dogs has moved from Hokkaido.
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