PS 34-60
Response to the amphibian chytrid fungus varies among strains and species
As part of an overall “biodiversity crisis” amphibian population declines and extinctions have occurred worldwide. Disease is one factor contributing to these declines. For example, mortality of amphibian hosts from infection by the fungal parasite Batrachochytrium dendrobatidis (Bd) is widespread. However, not all amphibian populations are adversely affected when exposed to Bd. This may be due in part to differential effects of Bd strains on hosts, yet there is a paucity of information on how different Bd strains affect host survival. Recent research has found a widespread, more recently evolved Bd clade (the global panzootic lineage, GPL) that is associated with increased virulence and amphibian population declines. We examined survival and pathogen load in three amphibian host species (Pacific tree frog, Western toad, and Cascades frog) after they were exposed to three GPL Bd strains from North and Central American isolates (JEL 630-Oregon, JEL 646-California, and JEL 425-Panama).
Results/Conclusions
Western toads had decreased survival from infection with Bd strains JEL 425 and JEL 646 but not JEL 630. Pacific tree frog and Cascades frog survival was not affected by any Bd strain tested. This study shows there are strain-dependent as well as species-dependent survival differences when amphibian hosts are exposed to Bd. These findings highlight the role strain variation exhibits in amphibian-Bd interaction and show the need for in vivo testing to ascertain virulence.