Batrachochytrium dendrobatidis (Bd) is a pathogenic chytrid fungus implicated in worldwide amphibian declines. Bd was thought to be highly hostspecific, however, we now know it can infect nonamphibian hosts, as well (e.g. crayfish). We recently determined that Bd can infect soil nematodes, but it was unclear as to whether these organisms are actually true reservoir hosts or vectors for the fungus. Here, with several laboratory and field experiments, we examined whether soil nematodes are reservoir hosts and vectors for Bd.
In laboratory experiments, we found that Bd and nematodes can survive long term on one another as their sole food source and we determined that Bd metabolites alone are detrimental to nematode populations. In addition to this laboratory work, we found that there are Bd-infected soil nematodes in the field and that nematode populations correlate to historical amphibian Bd prevalence in Gamboa, Panama. When there are multiple hosts for a pathogen, some can serve as reservoir hosts and vectors. This can affect disease dynamics by altering pathogen persistence, virulence, and movement among host populations.