White Nose Syndrome is a disease named for the distintive fungal growth around the muzzles and on the wings of hibernating bats. It is a poorly understood disease that has been associated with the deaths of more than 5.5 million bats within North America.
The first known case of White Nose Syndrome (or WNS) was in Schoharie County, New York cave back in 2006. Since that time the disease has rapidly spread and as of 2010 was found all over the United States and into Quebec, Ontario, Nova Scotia and New Brunswick. The first known case of WNS in Ontario was in March 2010.
Since being discovered research has been done and in late 2011 it was shown that the syndrome appears to be caused by a fungas called Geomyces destructans. Unfortunately, despite knowing the cause of WNS, there is still no known treatment or means of prevention. Researchers do have a good idea how how the fungus is spread and that is bat-to-bat transmission. In a lab experiment it was shown that direct physical contact was needed in order for the fungus to be spread, however it is also know that the fungus is a cold-loving fungus that grows in cold temperatures of below 20 C and that it will grow on bats while they are hibernating in caves and mines. So this means that not only can bats get the disease just by hibernating, they can also pass it to each other through direct contact.
Bat displaying White Nose Syndrome
As a result of this the mortality rate of some species affected by WNS is estimated at at about 95%. In fact, a once common species of bat (the little brown myotis) has in recent years suffered a major population collapse and is headed towards being at risk for a rapid extinction in the Northeastern United States. Should the population continue to decline as it has been, this species of bat could become extinct within 20 years.
Currently, there are 9 hibernating bat species confirmed to have the infection and Big Brown Bats, Northern long-eared bats, Tri-colored bats, Eastern small-footed bats and the Indiana bat have also suffered major mortality. In fact, many of these 9 species are listed on the United States endangered species list.
In Canada, caves infected with WNS are displaying a 90-100% bat mortality rate and according to a Department of Environmental Conservation survey, there is a 93% decline of Little Brown Bats in 23 caves.
So how is White Nose Syndrome killing the bats? Well bats infected with WNS have been known to display odd behaviour such as waking up from hibernation every 3-4 days as opposed to every 12-20 days and are flying outside during the day. The fungus also damages the connective tissues, muscles and skin of the bats while also disrupting their physiological functions. The bats wake up dehydrated and hungry during the cold winters when there are no insects to eat and unfortunately, about 90% of the bats affected perish due to starvation.
The impact that WNS is having and with continue to have is serious. Not only are many bat species facing the possibility of extinction, but because bats are the primary predators of night-flying insects and an individual bat can thousands of insects every night, with such a large number of bats dying there are more and more insects being uneaten, which could lead to crop damage. Insect-eating bats are crucial to a healthy ecosystem and bats play a crucial role in maintaining an ecological balance, which is why researchers are spending so much time trying to find a treatment or cure.