Preliminary observations on the biology of the Indonesian strain of Schistosoma japonicum: animals and oncomelanid snails.

Laboratory animals and subspecies of Oncomelania hupensis were exposed to experimental infections with a strain of Schistosoma japonicum from the Lindu Valley, Central Sulawesi, Indonesia. All laboratory animals given 50 cercariae were suspecptible to infection with the greatest number of worms being found in mice followed by Wistar rats, Long Evans rats, Mongolian gerbils, wild rats, hamsters and guinea pigs. Rabbits and the Taiwan monkeys given larger numbers of cercariae were also susceptible to infections. Adult worms were found to reach the largest size in the rabbit and Taiwan monkeys but many worms from rats were immature. Eggs from the Taiwan monkey were larger than those from a dog and from mice. Six subspecies or geographic strains of Oncomelania hupensis were exposed to 3 to 5 miracidia of the Indonesia strain of Schistosoma japonicum and only Oncomelania hupensis lindoensis and Oncomelania upensis chiui from Taiwan were susceptibile and produced cercariae while Oncomelania hupesis formosana from Changhua, Ilan and Kaohsium countries of Taiwan as well as Oncomalania hupensis quadrasi from the Philippines were considered refractory to infection.