Abstract
Investigations of the prevalencc of metagonimiasis by the fecal examinations have been carried out n the schoolchildren living around Lake Hachiro-gata, Akita Prefecture during the period from 1961 to 1967.
The prevalence rate of M. yokogawai among them was 17.0% in 1963. It decreased to 12.2% in 1964, 5.9% in 1965, 2.1% in 1966 and 0.1% in 1967.
The factors which influence the reduction of the infection in this area were throughout investigated. Regardless of the reclamation of the greater part of the lake, Salangichthys microdon infected with Metagonimus metacercariae were abundant in the remaining lake. However, its fishing was prohibited after the reclamation. The cause of the decrease in prevalence rate among the schoolchildren prebably is due to the fact that the inhabitants around the lake are rarely fed this fish.
