[Transition of occurrence of anisakiasis and its paratenic host fishes in Japan, with pathogenesis of anisakiasis].

The number of anisakiasis according to a nation-wide statistical survey totaled 4682 cases until June 1987 in Japan. Of these 4296 cases are gastric anisakiasis (including 215 cases of gastric terranovasis), 375 intestinal anisakiasis and 11 extra-gastrointestinal anisakiasis. Pseudoterranova larva does not invade the intestine, and worms are vomited in most cases. Clinical diagnosis of intestinal anisakiasis is more difficult than that of gastric anisakiasis, and it also is hard to find the worm itself in histopathological examination. Therefore the number of actual intestinal anisakiasis is probably 3 times more than that of the reported cases. The cases of gastrointestinal-wall perforation by worms are increasing, which means immune response by granuloma formation is important. The catches of paratenic hosts and the rate of infection vary with year. In addition, the kind of paratenic host fishes are different between the southern and northern areas of Japan. The paratenic hosts reported by patient are closely related to the catches of kinds of those fishes in the respective areas. Recently, cases by eating sardine are increasing in the southern area. Urticaria as a complication is related to the diagnostic rate, and intraperitoneal bacterial infection by the gastrointestinal perforation by worms is closely related to the prognosis.