Hepatitis B antigen and antibody were examined on 1, 984 adults in a village;for antigen with immune adherence hemagglutination method and for antibody with passive hemagglutionation method. Antigen were detected for 25 and antibody for 398 sera.The prevalence of 1.3 per cent for the antigen with this method is lower than that suspected from blood donors in Tokyo. Higher frequency was found in male, and in youth.In elderly persons, however, rather high prevalence was found than suspected before.
Twenty-five hepatitis B antigen positive individuals, found from the survey study on 1, 984 rural populations, were followed.On repeated examinations, 16 consistently carried the antigen, 7 changed to negative. The remaining one was the wife of a carrier and changed to show antibody. Transaminases were within normal limits in all cases. Hepatitis B virus is spreading unrecognisedly in general population and overt hepatitis is rather of exceptional case. The mechanism by which liver cirrhosis developes on carriers is the question open to future.
Sera from 1, 726 adults in Yachiho, a small village in Nagano, were examined for hepatitis B antigen, antibody and GOT value. Among them 1, 404 were found to have been examined in the study done one year ago. Fourteen individuals were consistently antigen positive. Seven antigen positive individuals changed to negative and 10 negative to positive. All antigen positive individuals showed normal SGOT level.
A dermatitis of unknown etiology has occurred among farmers working in paddy fields in the eastern area of Saitama Prefecture (Ozu et al., 1972). And it was proved to be caused by the invasion of a bird schistosome cercaria shed from Austropeplea ollula (Suzuki et al., 1973). In an attempt to dertermine the final host of this schistosome, a survey on the wild birds was undertaken in the endemic area. But, no natural infection was found in 8 Corvus corone, 7 Sturnus cineraceous, 5 Egretta garzetta, 4 Nycticorax nycticorax, 8Anas platyrhynchos, 7 A. crecca and 170 A. poecilorhyncha. Experimental infections with the cercariae were performed using domestic ducklings and canaries, and a bird schistosome egg could be found in feces of the domestic ducklings 20 days after the infection. The egg was crescent-shaped and the miracidium was clearly seen within. Based on the results of the experimental infections, the most probable final host of this schistosome in Saitama Prefecture was supposed to be the anatid birds.