The first case of schistosomiasis in the Philippines was reported in 1906.The case was a Filipino man who had never been out of the country. He eventually died with clinical impressions of amebiasis and bacterial infection. Autopsy confirmed the diagnosis of amebiasis, but with additional findings of Schistosoma ova in sections of the large intestine, liver, and lungs. Subsequently, schistosome ova were found in several cases among 500 autopsies reported in 1908 and in the feces of some prisoners admitted to Bilibid Prison, in the City of Manila in 1914.Several years later, in 1928, a case of Katayama disease (a toxemic syndrome with fever in the acute, early egg-laying phase of schistosomiasis) presenting as chronic appendicitis was reported.Attempts to demonstrate the intermediate host of the parasite were not successful until the discovery of the snail Oncomelania hupensis quadrasi in Palo, Leyte in 1932. S. japonicuminfection in mice, rabbits, and monkeys was then established by infecting the animals with cercariae (Schistosoma larvae) obtained from the Oncomelania snails ( Figure 1).