White nose syndrome (WNS) is a poorly understood disease associated with the deaths of hundreds of thousands of bats in the northeast. The condition, named for a distinctive ring of fungal growth around the muzzles, and on the wings of many affected animals, was first identified in a cave in Schoharie County, New York in February 2006, and started showing up in the news after January 2007. It spread to other New York caves and into Vermont, Massachusetts and Connecticut in 2008. In early 2009 it was confirmed in New Hampshire, New Jersey, Pennsylvania, and West Virginia. The condition has been found in over 25 caves and mines in the northeastern U.S.
The US Fish & Wildlife Service (USFWS) has called for a moratorium on caving activities in the affected areas, and strongly recommends that any clothing or equipment used in such areas be decontaminated after each use. The USFWS has released a draft of a National Plan to deal with WNS (download here).
The National Speleological Society (NSS) maintains an up-to-date page to keep cavers apprised of current events and advisories.
White-nose Syndrome from Gerrit Vyn on Vimeo.
A 2008 study determined that the fungus found on the muzzles, wings, and ears of infected bats is a member of the Geomyces genus. It is not known if the fungus is a causative agent in the bat deaths. The fungal growth may be an opportunistic infection, rather than the actual cause of the condition. A loss of winter fat stores, and the disruption of hibernation and feeding cycles caused by warm and variable winter weather have all been suggested as causes or contributing factors.
Extensive spraying of pesticides to combat West Nile Virus or other environmental toxins could be a cause by directly affecting the bats or reducing insect populations, their primary source of food.
One researcher suspects a cause of the syndrome may be bat flies and this possibility is being investigated. Bat flies are small parasites that live in a bat’s hair and feed on its blood. They may be involved in transmission of a pathogen.
Because no one yet knows how the condition spreads, cave management and preservation organizations have been requesting that cavers limit their activities and disinfect clothing and equipment that has been used in possibly infected caves. In some cases, access to caves is being closed entirely. Despite these efforts, the spread of the disease to Aeolus Cave, New England’s largest hibernaculum, which has had limited human access since 2004, “complicates” the theory that human activity is directly contributing to the condition. As of March 2008, the disease had spread to Vermont, western Massachusetts and northwestern Connecticut. In February 2009, it had spread to New Jersey, Pennsylvania, and eastern West Virginia. The migratory nature of bats threatens to spread the malady throughout the northeastern United States.
Alan Hicks with the New York State Department of Environmental Conservation has described the impact as “unprecedented” and “the gravest threat to bats … ever seen.” The mortality rate in some caves has exceeded 90 percent.
At greatest risk is the endangered Indiana bat, whose primary hibernaculum in New York has been affected. Deaths of eastern pipistrelles, northern long-eared myotis and little brown bats have also been attributed to the condition. The long-term impact of the reduction in bat populations may be an increase in insects, possibly even leading to crop damage or other economic impact in New England.
As of May 2009, bat colonies have been decimated in at least seven states, with an estimated half a million bats having died from the disease. This deprives the country, especially during the spring and summer, of a valuable natural pesticide as bats consume huge quantities of insects: as much as their own body weight each night.
The Forest Service estimates that the die-off from white-nose syndrome means that at least 2.4 million pounds of bugs (1.1million kg) will go uneaten and become a financial burden to farmers. Crop production may require more insecticide, raising environmental worries and pushing up grocery prices. Furthermore, the disease could threaten an already endangered species, such as Indiana bats and the big-eared bat, the official state bat of Virginia.
Comparisons have been raised to colony collapse disorder, another poorly-understood phenomenon resulting in the abrupt disappearance of Western honey bee colonies. Biologists are investigating the geographic extent of the outbreaks and collecting samples of affected bats. A geographic database is being developed to track the location of sites where WNS has been found, collecting information at each site in regards to the number of bats affected.
The data will be critical in tracking the extent and spread of WNS and in coordinating research efforts. The U.S. Fish and Wildlife Service is also partnering with the Northeastern Cave Conservancy to track movements of cavers that have visited affected sites in New York. It has also advised closing caves to explorers in 20 states, from the Midwest to New England. This directive, enforced with fines and jail, will soon be extended to 13 southern states. As one Virginia scientist stated, “If it gets into caves more to our south, in places like Tennessee, Kentucky, Georgia and Alabama, we’re going to be talking deaths in the millions.”Wikipedia contributors, “White nose syndrome,” Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php?title=White_nose_syndrome&oldid=315955670 (accessed October 2, 2009).