Detection of amphibian chytrid fungus on waterfowl integument in natural settings

The chytrid fungus Batrachochytrium dendrobatidis (Bd), the causal agent of the amphibian disease chytridiomycosis, has spread at an alarming rate since its discovery. Bd was initially thought to only infect keratinizing epithelial cells in amphibians, a core component of amphibian skin. However, recent studies have detected Bd on the integument of non-amphibian hosts. We conducted a survey of 3 duck species (gadwalls, green-winged teals, and mallards) to determine whether Bd DNA could be found on their feet. Bd was found on the feet, by quantitative PCR, of individuals from all 3 species (5/11 gadwalls, 4/8 green-winged teals, and 13/21 mallards), though there were no significant differences in zoospore presence or load between species. We conclude that these waterfowl species may act as vector hosts for Bd, adding to the growing list of potential waterfowl vectors. Future studies are needed to determine whether Bd on waterfowl feet is viable and infectious to amphibian hosts.