STUDIES ON THE LIFE-CYCLE OF ARTYFECHINOSTOMUM-ORAONI BANDYOPADHYAY, MANNA AND NANDY 1989 - EMBRYOGENESIS AND DEVELOPMENT IN THE INTERMEDIATE HOST

A study was undertaken to elucidate the life cycle of the parasite A. oraoni, isolated from man,:br: the purpose, operculated eggs were isol ated from faeces of oraon tribals belonging to the village Bandipore, district North 24-Parganas of West Bengal province of India. The purif ied eggs were incubated at different temperatures, salinity and pH. La rvae (miracidia) could be observed to develop between the 7th and 8th day of-incubation at a temperature range between 22 degrees - 30 degre es C. While the optimum pH was observed to be neutral, larval developm ent did not take place at salinity beyond 0.8 per cent. To identify th e correct intermediate host, all available species of snails from the study village were colonised and infected with the laboratory hatched miracidia from human derived operculated eggs. It was observed that of all the snails infected, only Lymnaea supported the development of re diae from miracidia, which could be observed on the 32nd post infectio n day. Considering the results of the experimental study, it was hypot hesised that Lymnaea spp. of snails under natural Condition also, migh t act as the first intermediate host for A. oraoni.