DIPLOID PARAGONIMUS-WESTERMANI - THE EXPERIMENTAL COMPLETION OF ITS LIFE-CYCLE

Experimental completion of the life-cycle of Paragonimus westermani (T rematoda: Troglotrematidae) (diploid type) from egg to adult has been achieved in the laboratory for the first time. A dog was fed metacerca riae of P. westermani from naturally infected freshwater crabs, Geothe lphusa dehaani. The adult flukes were recovered and their eggs were in cubated in water at 28-degrees-C, hatching after 20 days. Laboratory r eared marsh snails, Semisulcospira libertina, were exposed to miracidi a from embryonated eggs. One of 47 snails became infected with a large number of 2nd generation rediae containing fully mature cercariae 245 days after exposure. Paragonimus-free crabs (G. dehaani) were then in fected with the intramolluscan larvae. Of the 40 crabs examined 34-70 days after infection, 17 were infected with a total of 84 metacercaria e. A cat and 4 dogs were fed with 55 metacercariae obtained. Eighty to 100 days later, a total of 40 flukes was recovered; 39 flukes were ad ults with eggs in their uteri.