Susceptibility to the amphibian chytrid fungus varies with ontogeny in the direct-developing frog, Eleutherodactylus coqui.

Age-related differences in susceptibility to infectious disease are known from a wide variety of plant and animal taxonomic groups. For example, the immature immune systems of young vertebrates, along with limited prior exposure to pathogens and behavioral factors, can place juveniles at greater risk of acquiring and succumbing to a pathogen. We studied the ontogenetic susceptibility of terrestrial direct-developing frogs (Eleutherodactylus coqui) to the fungal pathogen, Batrachochytrium dendrobatidis (Bd), which is responsible for the decline of amphibian species worldwide.