[Possibility of invasion of Echinococcus into Honshu with pet dogs from Hokkaido and overseas].

Purpose: The number of pet dogs moving with their owners to Honshu, the main island of Japan, from Hokkaido, and the number of dogs imported from overseas were examined, and the possibility of invasion of Echinococcus multilocularis and E. granulosus with these dogs was discussed.

Methods: The number of pet dogs moving to Honshu-island from Hokkaido was examined with the movement notifications based on the Rabies Prevention Act in 29 prefectures during the period from 1996 to 2001. The number of pets was also examined by questionnaire targeting 3 aviation and 3 ferry companies. The number of dogs imported from overseas was examined with the Annual Reports of the Animal Quarantine Service of Japan, The sanitary conditions of hotels for pet owners were also examined with a questionnaire.

Results: Approximately 140 pet dogs were found to have officially moved annually from Hokkaido to Honshu during the study period. However, the actual number might be two to three times this estimate, because many dogs moved without notification. Nearly ten thousand pet dogs were transported a year to and from Honshu and Hokkaido by planes and ferries. A value of three thousand would be expected if people from Hokkaido were accompanying their pets at the rate of the registered dogs per population, one animal per 23 Hokkaido residents. Up to 30 pet dogs infested with E. multilocularis would probably be included per year, according to the infestation rate of 1% in Hokkaido. The number of imported dogs from overseas was assessed at approximately 15 thousand a year, but these dogs were not obligated to receive animal quarantine with respect to echinococcal infestation in Japan. Hotels for pet owners were considered to be managed rather sanitarily, though certain administrative guidance is necessary to prevent hydatid disease infection of travelers and hotel workers. The authors consider that dogs from Hokkaido and also from echinococcosis endemic countries should undergo fecal examination for parasite eggs to prevent invasion of the parasite into Honshu.

Conclusion: The authors propose the fecal examination of the dogs from Hokkaido and also from overseas for preventing invasion of E. multilocularis and E. granulosus into Honshu, Japan.