White-nose syndrome without borders: Pseudogymnoascus destructans infection tolerated in Europe and Palearctic Asia but not in North America

Abstract

A striking feature of white-nose syndrome, a fungal infection of hibernating bats, is the difference in infection outcome between North America and Europe. Here we show high WNS prevalence both in Europe and on the West Siberian Plain in Asia. Palearctic bat communities tolerate similar fungal loads of Pseudogymnoascus destructans infection as their Nearctic counterparts and histopathology indicates equal focal skin tissue invasiveness pathognomonic for WNS lesions. Fungal load positively correlates with disease intensity and it reaches highest values at intermediate latitudes. Prevalence and fungal load dynamics in Palearctic bats remained persistent and high between 2012 and 2014. Dominant haplotypes of five genes are widespread in North America, Europe and Asia, expanding the source region of white-nose syndrome to non-European hibernacula. Our data provides evidence for both endemicity and tolerance to this persistent virulent fungus in the Palearctic, suggesting that host-pathogen interaction equilibrium has been established.

The other white‐nose syndrome transcriptome: Tolerant and susceptible hosts respond differently to the pathogen Pseudogymnoascus destructans

“…In contrast to the North American situation, European and Asian bats exhibit mild symptoms or remain asymptomatic following exposure to P. destructans , and no WNS‐related mass mortality has been documented on either continent (Hoyt et al., 2016a,b; Wibbelt et al., 2010; Zukal et al., 2016). These outcomes may reflect tolerance (the host experiences pathogen loads comparable to those of susceptible species, but does not exhibit severe disease symptoms), or resistance (the host exhibits significantly lower pathogen loads compared to susceptible species).…”

“…These outcomes may reflect tolerance (the host experiences pathogen loads comparable to those of susceptible species, but does not exhibit severe disease symptoms), or resistance (the host exhibits significantly lower pathogen loads compared to susceptible species). Eurasian bats are considered tolerant to P. destructans (Zukal et al., 2016), presumably through coevolution with the pathogen (Leopardi, Blake, & Puechmaille, 2015). …”

Quantification of pathogen levels is necessary to compare responses to pathogen exposure: Comment on Davy et al. “The other white‐nose syndrome transcriptome”

“…WNS is caused by the psychrophile Pseudogymnoascus destructans , an ascomycete fungal pathogen (Gargas, Trest, Christensen, Volk, & Blehert, 2009; Lorch et al., 2011) that affects bats during hibernation. P. destructans can infect bats without causing mortality, as seen in Europe (Wibbelt et al., 2013; Zukal et al., 2016) and in some bats in North America (Frank et al., 2014; Lilley et al., 2016; Moore et al., 2018). An important question in the disease ecology of WNS is how hosts that are resistant or tolerant to infection respond differently than susceptible hosts.…”

Galleria mellonella experimental model for bat fungal pathogen Pseudogymnoascus destructans and human fungal pathogen Pseudogymnoascus pannorum

“…The latest surveillance and modeling data suggest that WNS is likely to lead to the regional extinction of some bat species in the United States while the disease remains well-tolerated among the European bats [3,4]. Pseudogymnoascus destructans is the fungal causal agent of WNS [5].…”

“…Bats infected with P. destructans exhibit histopathological lesions on wings and other body parts, are frequently aroused from hibernation-induced torpor, and possibly succumb to WNS due to fat depletion and starvation [9–11]. Some North American bat species and bats elsewhere in the world do not suffer from WNS-associated fatality likely due to a protective immune response against P. destructans [4,12–14]…”