The Epidemiology of Schistosomiasis Japonica in the Philippine Islands and Japan

Abstract

Summary and Conclusions 1. Schistosomiasis japonica is endemic in the Naujan municipality of Mindoro, P. I. It was found in approximately 40 per cent of a population sample in 1945 compared to 20 per cent in 1939. 2. At the time this survey was made the incidence of schistosomiasis japonica increased to a peak in the fourth decade, after which there was a drop in individuals over 40. 3. In this highly malarious population enlargement of the liver or spleen does not characterize proven cases of the disease, and these physical signs are not suitable for surveying individuals suspected of being infected. 4. The classical results of portal venous obstruction were encountered in only one-sixteenth of the proven cases of chronic schistosomiasis japonica found in this population. 5. A hitherto unreported area endemic for S. japonicum has been found in Pola municipality, sitio of Casiligon, Mindoro, P. I. 6. The incidence of infection of intermediate hosts by S. japonicum was found to be about 1 per cent of 1622 snails (O. quadrasi). 7. One of six carabao calves, nine of 13 pigs and eight of 14 dogs examined in this area yielded eggs of S. japonicum in their stools.