Abstract
Our epidemiological research on clonorchis sineneis conducted in Yamamoto-gun, Akita Prefecture from 1959 through 1961 reached to the following results:
1) The prevalence of this parasite in the eight districts of this county, among 998 villagers and 3445 primary school childsen attending nine schools was 10.9-66.0% and 0.9-17.4% respectively. By districts, the rate was higher on the northern coast of Hachiro-gata, and especially high around Asanai-numa.
2) Sarcocheilichthys variegatus, acheilognatus lanceolata moriokae, pseudo perilampus typus and pseudorasbora parva obtained from Asanai-numa and Otomo-numa were found to carry metacercaria (clonorchis metacercaria). The acheilognatus lanceolata moriokae caught in Hachiro-gata was also proved to be carrying metacercaria.
3) Research into Asanai-numa and Aka-numa evidenced the inhabitation of parafossarulus manchourieus-Ebourguigant, the first intermediate host of that parasite.
4) On the basis of the above-mentioned results, it became evident that the county concerned should be classified among the districts hardest hit with clonorchis sinensis.
