The biology of Contracaecum osculatum sensu lato and C. osculatum A (Nematoda: Anisakidae) in Japanese waters : a review

わが国周辺海域の魚類や鰭脚類にそれぞれ幼虫や成虫が寄生するアニサキス科線虫のContracaecum osculatum sensu lato とC. osculatum A の生物学的知見を纏めた。わが国では1998年にC. osculatum A が見出されるまでは,近年C. osculatum s. l. とされる線虫が型を付した名前や単にC. osculatum として報告されてきた。これまでにC. osculatum s. l. はオキアミ類1種,海産魚類13種,鰭脚類6種から記録され,C. osculatum A はスケトウダラとアゴヒゲアザラシに見出されている。C. osculatum s. l. の幼虫はスケトウダラとマダラ,特に前者によく寄生している。C. osculatum s. l. の幼虫を実験的に子犬に感染させると腸粘膜に穿入するため,人間の消化管壁にも穿入する可能性があり,実際にわが国で人体寄生例が2例知られる。

The paper reviews the biology of Contracaecum osculatum sensu lato and C. osculatum A, a member of the C. osculatum complex, parasitic in marine finfishes as larvae and in pinnipeds as adults in Japanese waters. Before C. osculatum A was discovered in 1998, larval nematodes identifiable as C. osculatum s. l. had been reported as various types of Contracaecum or C. osculatum. To date, larval and adult C. osculatum s. l. have been recorded from 13 species of teleosts and six species of pinnipeds, respectively, and there is a record of larval C. osculatum s. l. from euphausids. Larval and adult C. osculatum A are known from Alaska pollock Theragra chalcogramma and bearded seals Erignathus barbatus, respectively. Larval C. osculatum s. l. are commonly found in commercially important gadid fishes, especially in Alaska pollock. Two cases of human infection with C. osculatum s. l. have been reported in Hokkaido. Since larval C. osculatum s. l. can invade the intestinal mucosa of experimentally infected puppies, the larvae have the potential to penetrate the wall of the human digestive canal.