Study on Schistosoma sinensium in Fang district, Chiangmai province, Thailand.

A survey on human infection and possible natural definitive host of Schistosoma sinensium was carried out in Fang District, Chiangmai Province, North Thailand, where Tricula bollingi snails which harbour cercariae of S. sinensium inhabits. Stool examination of the people in the two villages along the stream, where T. bollingi were found, was by formalin-ether concentration technique and by Stoll's method. The stools were found to be negative for S. sinensium eggs. Field rats were also trapped and examined for the presence of S. sinensium. Adult worms and eggs of S. sinensium were found in the mesenteric veins and livers, respectively, of the field rats, Rattus rattus, captured in the rice fields along the stream.