Epidemiological tracing of Batrachochytrium salamandrivorans identifies widespread infection and associated mortalities in private amphibian collections

Abstract

The amphibian chytrid fungus Batrachochytrium salamandrivorans (Bsal) infects newts and salamanders (urodele amphibians), in which it can cause fatal disease. This pathogen has caused dramatic fire salamander population declines in Belgium, the Netherlands and Germany since its discovery in 2010. Thought to be native to Asia, it has been hypothesised that Bsal was introduced to Europe with the importation of infected amphibians for the commercial pet trade. Following the discovery of Bsal in captive amphibians in the United Kingdom in 2015, we used contact-tracing to identify epidemiologically-linked private amphibian collections in Western Europe. Of 16 linked collections identified, animals were tested from 11 and urodeles tested positive for Bsal in seven, including the identification of the pathogen in Spain for the first time. Mortality of Bsal-positive individuals was observed in five collections. Our results indicate that Bsal is likely widespread within the private amphibian trade, at least in Europe. These findings are important for informing policy regarding Bsal control strategies.

Conservation risk of Batrachochytrium salamandrivorans to endemic lungless salamanders

“…Bsal was isolated in 2012 from a moribund European fire salamander ( Salamandra salamandra ) from a population in Bunderbos, the Netherlands, that had been declining since 2010 (Martel et al., ). Since its isolation, Bsal has been detected in captive and wild populations in six European countries (Fitzpatrick, Pasmans, Martel, & Cunningham, ; González et al., ; Sabino Pinto et al., ; Spitzen‐van der Sluijs et al., ; Stegen et al., ). Bsal ’s emergence has had negative impacts on susceptible host species.…”

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): Batrachochytrium salamandrivorans (Bsal)

“…Thus far, Bsal has been demonstrated in 15 wild populations of salamanders in Belgium, Germany and the Netherlands (Spitzen‐van der Sluijs et al., ) and in five populations in captivity in Germany (1), the Netherlands (2), Spain (1) and the United Kingdom (1) (Sabino‐Pinto et al., ; Fitzpatrick et al., ). The total number of wild and captive populations of salamanders in Europe is not known.…”

“…In captive salamanders: Germany, the Netherlands, Spain, the United Kingdom, (Fitzpatrick et al., ; Sabino‐Pinto et al., ).…”

“…The only available qPCR protocol currently routinely used internationally as the reference standard for Bsal detection in skin and skin swabs is the one developed by Blooi et al. () that has been used in several laboratories providing consistent results (Sabino‐Pinto et al., ; Fitzpatrick et al., ; Spitzen‐van der Sluijs et al., ). The diagnostic characteristics of this test has been recently evaluated by Thomas et al.…”

“…Supporting Yes for 1 (cat. B): It is present in wild populations in Belgium, Germany, the Netherlands (Spitzen‐van der Sluijs et al., ) and in captive salamanders in Germany, the Netherlands, Spain and the United Kingdom (Fitzpatrick et al., ; Sabino‐Pinto et al., ). It appears that the disease can maintain itself in the population without introduction from outside. …”