The causes of amphibian deformities and their role in widespread amphibian
declines remain conjectural. Severe Limb abnormalities were induced at high
frequencies in Pacific treefrogs (Hyla regilla) exposed to cercariae of a
trematode parasite (Ribeiroia sp.). The abnormalities closely matched those
observed at field sites, and an increase in parasite density caused an inc
rease in abnormality frequency and a decline in tadpole survivorship. These
findings call for further investigation of parasite infection as a cause o
f amphibian deformities in other sites and species.