Ecological studies on the lung fluke, Paragonimus ohirai Miyazaki, 1939. 1 Infection rate with P. ohirai metacercariae of brackish water crabs collected from the six rivers in the Tokai district, central Japan.

Abstract

In the area of the Ibi, Nagara and Kiso rivers in the Tokai district, central Japan, a survey for the detection of Paragonimus ohirai in snails and rodents was performed during the period between October 1983 and October 1985. Snails, Assiminea parasitologica, positive for P. ohirai cercaria were found in 2 of 5 study sites. The over-all infection rates were 0.41% at the sites on the Ibi and 0.45% at those on the Kiso river. Two species of rodents, Rattus norvegicus and Apodemus speciosus, were collected, the infection rate for P. ohirai being 50% in the former and 0% in the latter species. The results of the present study and our previous report (Matsuo and Makiya, 1985) disclosed the life cycle of P. ohirai in the areas along the Ibi, Nagara and Kiso rivers; A. parasitologica is the 1st intermediate host, Sesarma dehaani and S. intermedia are the 2nd intermediate host, and R. norvegicus is the final host.