Batrachochytrium salamandrivorans (Bsal) not detected in an intensive survey of wild North American amphibians

Abstract

the salamander chytrid fungus (Batrachochytrium salamandrivorans [Bsal]) is causing massive mortality of salamanders in europe. the potential for spread via international trade into north America and the high diversity of salamanders has catalyzed concern about Bsal in the U.S. Surveillance programs for invading pathogens must initially meet challenges that include low rates of occurrence on the landscape, low prevalence at a site, and imperfect detection of the diagnostic tests. We implemented a large-scale survey to determine if Bsal was present in north America designed to target taxa and localities where Bsal was determined highest risk to be present based on species susceptibility and geography. our analysis included a Bayesian model to estimate the probability of occurrence of Bsal given our prior knowledge of the occurrence and prevalence of the pathogen. We

Putative resistance and tolerance mechanisms have little impact on disease progression for an emerging salamander pathogen

“…Animals were not tested for Bsal prior to the experiment. They were presumed to be negative as Bsal has not been detected in the United States (Waddle et al., 2020).…”

“…Bsal is a relative of the amphibian chytrid fungus Batrachochytrium dendrobatidis ( Bd ), which has caused declines and extinctions in hundreds of amphibian species worldwide (Scheele et al., 2019). While Bsal has not successfully invaded North America as of 2020 (Waddle et al., 2020), the high salamander diversity and habitat suitability for Bsal in North America has raised substantial concerns about the potential impact of Bsal if it does invade (Gray et al., 2015; Yap et al., 2015). Necessary steps for assessing the risk of North American salamander species to Bsal include determining how populations and species differ in resistance and tolerance to Bsal infection (Carter et al., 2020; Gray et al., 2015), the mechanisms underlying these host defence strategies, and how changes in host defences affect the impacts of Bsal on host populations (Canessa et al., 2018).…”

Immunological Aspects of Chytridiomycosis

“…It has a wide host range, including frogs, salamanders and caecilians, but is most virulent in frogs [15,16]. Bsal is known from outbreaks in European salamanders, has a similar ancestral range to Bd, but has not yet been detected in North America, although its introduction is likely [6,14,17,18].…”

“…It has a wide host range, including frogs, salamanders and caecilians, but is most virulent in frogs [ 15 , 16 ]. Bsal is known from outbreaks in European salamanders, has a similar ancestral range to Bd, but has not yet been detected in North America, although its introduction is likely [ 6 , 14 , 17 , 18 ]. While it infects salamanders and frogs, it does not appear to produce large-scale mortality in frogs, possibly due to its lower thermal preference (5–25 °C, with optimal growth at 10–15 °C) [ 6 , 16 ].…”

Preparing for invasion: Assessing risk of infection by chytrid fungi in southeastern plethodontid salamanders

“…Early detection and rapid response to contain chytrid pathogens will require systematic efforts across multiple sectors (Grant et al, 2016; Reaser et al, 2020). Fortunately, recent intensive surveys have not detected Bsal in North America (Waddle et al, 2020), which suggests that the pathogen is still confined to Europe and Asia.…”