High levels of prevalence related to age and body condition: Host-parasite interactions in a water frog pelophylax kl. hispanicus

Host traits can significantly influence patterns of infection and disease. Here, we studied the helminths parasitizing the Italian edible frog Pelophylax kl. hispanicus, giving special attention to the relationship between parasites and host traits such as sex, snout vent length, weight and body condition. The helminth community was composed of seven species: three trematode species (Diplodiscus subclavatus, Gorgodera cygnoides, Pleurogenes claviger), three nematode species (Icosiella neglecta, Oswaldocruzia filiformis, Rhabdias sp.) and one acanthocephalan species (Pomphorhychus laevis). We found that prevalence was positively correlated with snout-vent length and weight, but did not differ with body condition or sex. We found that prevalence and mean species richness increased with age. Our results show that abundance of Icosiella neglecta was positively correlated with higher values for host body condition. In fact, we found that high prevalence and mean species richness do not necessarily imply poorer body condition in the parasitized host. In conclusion, our results show that the helminth community in this taxon has great diversity, and this host-parasite system seems to be evolved to low levels of virulence, helminths maintaining a commensal relationship with this frog.