Freshwater snails and the green algae Cladophora are probably not hosts of Batrachochytrium dendrobatidis

AbstractBatrachochytrium dendrobatidis (Bd) is a pathogenic fungus that has devastated amphibian populations globally by causing the disease chytridiomycosis. Batrachochytrium dendrobatidis is capable of infecting non‐amphibian hosts, such as crayfish, and has been detected on reptile and bird species. Given the taxonomic heterogeneity in the known hosts and vectors of Bd, it is likely that there is a diversity of undiscovered non‐amphibian hosts of the fungus. Here, we investigated whether Bd could survive on freshwater snails ( Physella acuta ) and Cladophora algae. We exposed small and large snails ( n  = 15 snails/size category), Cladophora algae ( n  = 5), and artificial spring water controls (ASW; n  = 5) to live Bd. We also maintained Bd‐free control snails ( n  = 5 snails/size category) in ASW. All treatments were maintained for 7 weeks at 18°C. Mortality was checked three times a week, snails were weighed every 2 weeks, and 7 weeks after exposure, the snails, algae, and water were tested for Bd using quantitative polymerase chain reaction. We found that Bd did not grow on live snails, algae, or ASW long term. Additionally, live snails ( n  = 20) collected from Bd‐positive ponds in California were all negative for Bd, as well. Given that we found no Bd on the experimentally exposed or field swabbed snails, snails are probably not a reservoir host of Bd. While negative results are often not published, Bd is one of the deadliest pathogens on earth; it is essential to know what is and is not capable of maintaining Bd for well‐designed disease models.