White-Nose Syndrome in Bats

             White-nose syndrome is a disease affecting hibernating bats. It is named for the white fungus that appears on the muzzle of hibernating bats. WNS is associated with extensive mortality of bats in eastern North America. First documented in New York in the winter of 2006-2007, WNS has now spread across the eastern US and Canada. WNS has killed more than 5.7-6.7 million bats in eastern North America, killing between 90-100% of bats in some hibernating groups. Eleven cave hibernating bats, including four endangered species and subspecies, have been identified as victims and potential victims of WNS. At the end of the 2011-2012 hibernating season, bats with WNS were confirmed in 19 states and 4 Canadian provinces. WNS causes the bats to exhibit bizarre behaviors, flying outside in the day during the cold winter months and clustering near the entrances of caves to hibernate.

Scientists are searching for answers about the cause of these bat deaths. Fish and Wildlife Servies has allocated approximately $7.9 million for WNS research. So far, the fungus Geomyces destructans has been identified as a possible cause of WNS. Scientists are searching further into how fungal infection and transmission occurs and how it can be prevented. We do not know if the fungus is causing deaths or is a symptom of the actual killer. Fungal hyphae replace hair follicles and associated sweat glands, invading surrounding tissues. Hyphae also eroded the epidermis of ears and wings (Blehert et al, 2008). Carol Meteyer, with others, is researching the essential criteria in diagnosis of WNS. She discusses in her paper the lack of inflammation response to the fungal invasion of epidermal skin tissue in bats still in hibernation compared to the extreme inflammation of bats collected outside of the hibernacula post-winter.

There is still much to learn about this infectious fungi and the way it is decimating bat populations. We hold a certain amount of responsibility in this issue because WNS may be a human-transmitted fungus. Awareness is essential, and early detection of the fungi in hibernacula will be incredibly important in slowing (and hopefully stopping) the spread of WNS. A national plan is being put into effect involving surveillance, population monitoring, and disease management programs in all infected states and provinces. Visit whitenosesyndrome.org for more information.