Larval Gnathostomes Found in Reptiles in Japan and Experimental Life Cycle of Gnathostoma nipponicum

Abstract

As only the adult of Gnathostoma nipponicum is known, 129 snakes and 33 weasels obtained in Kagawa Prefecture, Japan were examined for larvae. Hitherto undocumented larvae, later identified as G. nipponicum, were recovered from three snakes and one weasel. The life cycle was experimentally completed from eggs to adult worms. Cyclops, the first intermediate hosts, were infected by feeding them newly hatched larvae from uterine eggs. Advanced third-stage larvae were obtained from two rats and one mouse which had ingested early third-stage larvae from cyclops. A ferret fed advanced third-stage larvae from rats had adult worms in esophageal tumors 100 days after exposure.