SPONTANEOUS LARVAL GNATHOSTOMA-NIPPONICUM INFECTION IN FROGS

From June 1993 to September 1997, a survey was carried out for the pre valence of larval Gnathostoma nipponicum infection in several kinds of frogs, toads, and their tadpoles collected from an endemic area of th is nematode in Aomori Prefecture. Two frog species, one of 436 (0.2%) Rana nigromaculata and 51 of 147 (34.7%) R. catesbeiana were infected, and a total of 446 advanced third-stage larvae (AdL3) of G. nipponicu m were recovered. These results confirmed that two frog species which can serve as the second intermediate and/or paratenic hosts in the lif e cycle of G. nipponicum exist in nature. This report is the first rec ord of spontaneous infection of frogs with AdL3 of G. nipponicum.