White-nose syndrome attributed to death of over 5 million bats in northeast

by Alys Granados

As part a two-year initiative to bring awareness to bat conservation, research, and education, the United Nations Environment Programme declared 2011 and 2012 the “Year of the Bat”. Many bat species are threatened by habitat loss and deforestation, as illustrated in North America. However, in northeastern Canada and the United States, a recently discovered disease called White-Nose Syndrome (WNS) has had a devastating effect on bat populations, with the potential to cause local extinctions.

WNS is caused by a fungus (Geomyces destructans) that forms as a white area around a bat’s nose, wings, and/or ears. It was discovered in 2006 in New York state and has since spread to other states in the northeast. In 2010, infected bats were found in Ontario and Quebec, while in March of last year, WNS was confirmed in New Brunswick. There are also cases of WNS affecting bats in Nova Scotia.

There is no cure yet for WNS and much about it remains unknown, though the social behavior of bats seems to facilitate its transmission.  During the winter, hundreds of bats hibernate together in a single cave. Individuals with WNS are more likely to wake up early from hibernation (before food becomes available). They will show abnormal behavior during the winter, such as flying around during the day. This causes them to prematurely use up their fat reserves and can result in them freezing or starving to death. On average, bat numbers have decreased by 73% in hibernation areas wherever the fungus was present, with mortality in some areas reaching 100%.

WNS is back in the news, due to a recent report released by the US Fish and Wildlife Service. Biologists estimate the disease to have killed 5.7 to 6.7 million bats since 2006, an estimate five times higher than that from a previous report in 2009. These numbers are far greater than expected and emphasize the severity of WNS, with mortality expected to increase as it continues to spread.  WNS has been confirmed in at least seven species, including the little brown bat (Myotis lucifugus). This was one of the most common bats in the northeast, but is now in serious danger of becoming regionally extinct, with over 1 million deaths attributed to WNS. Scientists have even predicted a 99% chance of regional extinction within the next 14 years, should bat declines continue at rates similar to 2006-2009 levels. Further research in identifying how to stop the spread of WNS is thus central to preventing further declines.

What can you do?
People cannot contract WNS, yet we still play an important role in its spread as humans can carry the disease on clothing and/or gear from cave to cave.  Indeed, incidence of WNS seems related to the location of popular caver destinations. In the US, government biologists released a cave advisory in 2009, recommending that people stay out of caves (with the exception of tourist/commercial caves) in states where WNS exists, as much about its transmission remains unknown. Similar guidelines should be followed in Canada, including keeping out of caves where bats may hibernate or are present, as early stages of WNS are less recognizable.

If you see any bats with WNS or exhibiting abnormal behavior (such as flying during the day), report it to the Canadian Cooperative Wildlife Health Centre at 1-866-673-4781 or the Natural Resources Information Centre at 1-800-667-1940.

For a short video about WNS, head over to the Ontario Ministry of Natural Resources website.

See how WNS has spread across the northeast since its discovery through this map by Bat Conservation International.

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