A fungus that is wiping out millions of North America’s bat population originated in Europe and probably spread to the USA and Canada through human activity such as migration and agriculture. That’s according to new genetic research from the Royal Veterinary College (RVC) in partnership with the University of Greifswald and University College Dublin, that is to be published in academic journal, Current Biology.
White-nose syndrome (WNS) is a disease that was first found in North American bats in 2006. Since then it is estimated that it has killed more than five million of the animals across large parts of North Eastern America and Canada. The disease is named after the white fungus, Pseudogymnoascus destructans (Pd), that infects the muzzle, ears, and wings of hibernating bats. The fungus has spread rapidly across the region with mass mortality up to 99%, with no treatment or practical way of halting the disease.
Scientists and conservationists suspect that the origins of the Pd began in Europe and were brought to North America through human activity. This latest research provides the strongest evidence yet that this is the case.
The joint study investigated Pd’s origins on a molecular level. This allowed the researchers to evaluate the genetic similarity of European and American Pd and assess whether Europe was a likely source for the recent introduction of the pathogen to North America. It found a higher diversity of Pd within the European population of bats versus North America, demonstrating a long term presence in Europe, and strongly supporting the introduction of the fungus to the eastern region of the USA from Europe.
One of the researchers on the project was Stefania Leopardi, who completed her Wild Animal Health MSc course at the RVC under the supervision of Molecular Parasitology expert, Dr Damer Blake. Ms Leopardi said: “Given there is no bat migrating between North America and Europe, it is very likely that the fungus has been introduced to North America via anthropogenic activities”. “The introduction of new pathogens into native populations represents the undesired consequence of globalisation and the unprecedented movement of humans, animals and other things such as agriculture materials or ballast water.”
Pd does not have the same mass mortality effect on European bats as it does in North America. Indeed, native European bats seem to have a resistance resulting from coevolution with the fungal pathogen. This was another key factor in suggesting Europe was the origin of the Pd fungus: "Demonstrating the European origin of the North America population of Pd is a first important step in better understanding factors underlying the emergence of this devastating disease. Our study paves the way for future research to uncover the exact site of origin in Europe, information that would likely shed light into the exact nature of the human activity responsible for the introduction" said Dr. Sebastien Puechmaille, University of Greifswald, Germany and senior author of this paper.
Not only is WNS having a devastating effect on the bat population there is also wider consequences for the entire ecosystem of the region. Ms Leopardi added: “Hibernating bats in North America are mostly insectivorous and have fundamental roles in insect control, pest control and plant pollination. WNS might then disrupt a fragile equilibrium with ecological consequences well beyond the loss of a single species.”
This paper is due to be published with Current Biology on the 16th of March. [White-Nose Syndrome fungus introduced from Europe to North America DOI: 10.1016/j.cub.2015.01.047]. The research was supported by the Royal Veterinary College/Zoological Society of London, the British Veterinary Zoological Society and Bat Conservation International.
Culture of Pseudogymnoascus destructans. Photo by Dr. Dan Linder/USDA Forest Service Photograph of a hibernating Myotis myotis infected with Pseudogymnoascus destructans (visible white fungal growth on the nose, ears and forearms). This photograph was taken on March 2nd 2015 during a survey at a hibernacula in Germany, near the city of Greifswald. © S.J. Puechmaille, 2015.