Differences in Infection Levels of Salamander Hosts by Metacercariae of the Trematode Metagonimoides oregonensis (Digenea: Heterophyidae)

The Appalachian trematode currently recognized as Metagonimoides oregonensis utilizes the salamander Desmognathus amphileucus as its primary second intermediate host, although it also infects other salamander species. Previous workers have suggested that D. amphileucus is the most frequently used host because of its relatively large size and long aquatic larval stage, both combining to enhance exposure to trematode cercariae relative to other available salamander species. We tested this hypothesis by comparing relative prevalence and relative intensity between D. amphileucus and the sympatric, distantly related Pseudotriton ruber, which has a similarly sized larval form and a similar length of larval life. We found significantly higher levels of both relative prevalence and relative intensity of metacercarial infection in D. amphileucus, suggesting that cercariae of this trematode actively utilize D. amphileucus as a second intermediate host over more distantly related species.