Published online by Cambridge University Press: 05 June 2009
A total of 444 adult frogs (Rana temporaria) were obtained from three sites in the east of Ireland. Oswaldocruzia filiformis was present at all times of the year; overall, 64% of the frogs were infected, with a mean burden of 5 worms/frog. Most of the parasites were in the first half of the small intestine. A single gross lesion associated with a high worm burden is described. Female parasites were more abundant than males. Most parasitic stages of O. filiformis overwintered in hibernating hosts. Seasonal patterns in the levels of parasitization were not discerned. The intensity of infection was significantly greater in female than male frogs at one of the sites. There was little correlation between the size of host and degree of parasitization. None of the 45 frog tadpoles examined harboured O. filiformis. Frogs became infected by August of their first year.