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.

Growth and localization of Angiostrongylus cantonensis in the molluscan host, Achatina fulica.

The development of the rat lung worm Angiostrongylus cantonensis within the giant African snail Achatina fulica is reported. In this host, ingested first stage larvae penetrate the intestinal wall into the hemocoel and migrate to the mantle where they undergo two molts and become third stage larvae within 24 days. The mantle, harboring 85% of the total number recovered is the major location of infective larvae. The kidney contains about 11% but few larvae are found in the remaining visceral organs. Host response consists of encapsulation; destruction by means of phagocytosis was not observed.