Multi-year amphibian sampling for Batrachochytrium dendrobatidis and B. salamandrivorans in a tributary of the Tallapoosa River, Alabama

Amphibians are susceptible to various diseases, including infectious diseases, neoplasia, toxicosis, and nutritional and environmental deficits (reviewed by Hyatt et al. 2000; Densmore and Green 2007). Since the 1990s, chytrid fungi have become widely recognized as causing chytridiomycosis, a severe disease of keratinized skin tissues that poses a major threat to amphibian species diversity and distributions (Berger et al. 1998; Daszak et al. 1999; Martel et al. 2014). The first chytrid fungus identified as pathogenic to amphibians, Batrachochytrium dendrobatidis (Bd), occurs on every continent inhabited by amphibians and has been associated with amphibian population declines worldwide as well as some extinctions (e.g., Berger et al. 1998; Lips et al. 2006; Skerratt et al. 2007). Some species or individuals are more susceptible to Bd and more likely to experience clinical or lethal infections, while others are more resistant and some may remain subclinical (e.g., Daszak et al. 1999). In 2013, another Batrachochytrium species, B. salamandrivorans (Bsal), was discovered and described by scientists in wild and captive European Fire Salamanders (Salamandra salamandra). Batrachochytrium salamandrivorans appears to have originated in Asia and is lethal to salamanders of the United States from families Plethodontidae and Salamandridae but has not yet spread to North America (Martel et al. 2013, 2014; Grant et al. 2016). Due to significant concerns over the potential negative effects of Bsal on North American salamanders, and broader impacts of both of these chytrids on amphibians, widely screening amphibians for these pathogens is critical to evaluating Bd/Bsal distributions and associated sources and risks.