The investigation of factors underlying the emergence of fungal diseases in wildlife has gained significance as a consequence of drastic declines in amphibians, where the fungus Batrachochytrium dendrobatidis has caused the greatest disease-driven loss of biodiversity ever documented [1]. Identification of the causative agent and its origin (native versus introduced) is a crucial step in understanding and controlling a disease [2]. Whereas genetic studies on the origin of B. dendrobatidis have illuminated the mechanisms behind the global emergence of amphibian chytridiomycosis [3], the origin of another recently-emerged fungal disease, White-Nose Syndrome (WNS) and its causative agent, Pseudogymnoascus destructans, remains unresolved [2,4]. WNS is decimating multiple North American bat species with an estimated death toll reaching 5-6 million. Here, we present the first informative molecular comparison between isolates from North America and Europe and provide strong evidence for the long-term presence of the fungus in Europe and a recent introduction into North America. Our results further demonstrate great genetic similarity between the North American and some European fungal populations, indicating the likely source population for this introduction from Europe.

Coronaviruses (CoVs) have been documented in almost every species of bat sampled. Bat CoVs exhibit both extensive genetic diversity and a broad geographic range, indicative of a long-standing host association. Despite this, the respective roles of long-term virus-host co-divergence and cross-species transmission (host-jumping) in the evolution of bat coronaviruses are unclear. Using a phylogenetic approach we provide evidence that CoV diversity in bats is shaped by both species richness and their geographical distribution, and that CoVs exhibit clustering at the level of bat genera, with these genus-specific clusters largely associated with distinct CoV species. Co-phylogenetic analyses revealed that cross-species transmission has been more common than co-divergence across coronavirus evolution as a whole, and that cross-species transmission events were more likely between sympatric bat hosts. Notably, however, an analysis of the CoV RNA polymerase phylogeny suggested that many such host-jumps likely resulted in short-term spill-over infections, with little evidence for sustained onward transmission in new co-roosting host species.

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The wide geographical distribution and genetic diversity of bat-associated lyssaviruses (LYSVs) across Europe suggest that similar viruses may also be harboured in Italian insectivorous bats. Indeed, bats were first included within the passive national surveillance programme for rabies in wildlife in the 1980s, while active surveillance has been performed since 2008. The active surveillance strategies implemented allowed us to detect neutralizing antibodies directed towards European bat 1 lyssavirus in six out of the nine maternity colonies object of the study across the whole country. Seropositive bats were Myotis myotis, M. blythii and Tadarida teniotis. On the contrary, the virus was neither detected through passive nor active surveillance, suggesting that fatal neurological infection is rare also in seropositive colonies. Although the number of tested samples has steadily increased in recent years, submission turned out to be rather sporadic and did not include carcasses from bat species that account for the majority of LYSVs cases in Europe, such as Eptesicus serotinus, M. daubentonii, M. dasycneme and M. nattereri. A closer collaboration with bat handlers is therefore mandatory to improve passive surveillance and decrypt the significance of serological data obtained up to now.