Schistosomiasis japonica in field rats in Leyte, Philippines.

Approximately 73% of wild caught field rats were found infected with schistosomiasis japonica as revealed by the finding of eggs in liver sections; 49% of rats showed eggs in histological sections of the large intestine and about 13% showed eggs in their stools. Male rats appear to have higher schistosomiasis infection rate then female rats and that rats caught from endemic areas with smooth or normal looking livers do not necessarily mean that they are not infected with schistosomiasis. Examination for miracidia using only 2-3 pellets of field rat's stool by Faust-Meleney egg hatching technique revealed that 58% of them were positive with a mean of 5 miracidia per rat. A slightly lower hatchability rate was observed among laboratory infected white rats. Our figures on hatchability of Schistosoma ova are higher than those obtained by Pesigan and his co-workers probably because we used freshly collected rat faeces.