The Virginia Department of Game and Inland Fisheries is investigating two recent potential occurrences of white-nose syndrome in bats in Virginia.
While conducting winter surveys of caves where bats hibernate, known as hibernacula, biologists and volunteers from VDGIF, the Virginia Department of Conservation and Recreation, the U.S. Fish and Wildlife Service, and the Virginia Speleological Survey discovered bats that showed signs of WNS in Breathing Cave in Bath County. Soon after, similar symptoms were found in bats in Clover Hollow Cave in Giles County.
According to a release on March 9, specimens were collected and sent to the U.S. Geological Survey National Wildlife Health Center in Madison, Wisconsin for analysis. It will take from two to three weeks for results to be available.
White-nose syndrome was first found in the winter of 2006-2007, when bats in several caves around Albany, New York displayed a white fungus growing around their muzzles, ears, and wings. By spring 2008, thousands of bats had died and conditions had spread to other sites in New York and adjacent states.
By the winter of 2008-2009, WNS had spread to bats in Vermont, Massachusetts, Connecticut, Pennsylvania, New Jersey, and West Virginia, and is suspected in New Hampshire. Scientists have been alarmed by the rapid and far-reaching spread of the syndrome.
Little is known about WNS, but one common symptom in these cases is the presence of this newly-identified fungus. How the fungus affects bats remains unclear. No known human health issues have been identified.
During the summer and early fall in Virginia, bats feed on insects and build body fat reserves critical for successful hibernation and survival through the winter months. Bat colonies consume thousands of insects in a single night, including mosquitoes and beetles. During hibernation, the metabolism of bats slows dramatically, virtually shutting down, to conserve fat reserves. Bats emerge in the spring ready to consume insects, give birth, raise their young pups, and continue their life cycle.
Bats collected from known WNS caves have depleted fat reserves; some even have appeared to starve to death. Bats suspected of having WNS appear to arouse more often and are more active during the hibernation period. Reports of bats found flying outside of mines or caves, apparently trying to find food, at a time when they should be hibernating, are symptomatic of the syndrome. WNS is almost always fatal to affected bats.
The impact of white-nose syndrome on bat populations could be highly significant if the condition cannot be controlled and continues to spread. Some WNS caves in New York have experienced declines of more than 90 percent of the bat populations.
Losses in bat populations of this magnitude will cause a substantial ripple effect due to the important role that bats play as insect feeders, as a food source for other animals (hawks, owls, raccoons, skunks, and other animals that prey on bats) and with their contributions to cave ecosystems.
How WNS is spread is under investigation, but it is suspected that transmission of the syndrome can occur by both bat and human traffic in caves. Many of the caves where WNS has been confirmed have been popular sites for recreational caving. Huge geographical leaps in WNS occurrences beyond the migration distances of bats, and in popular recreational caves, indicate that people who visit caves may inadvertently play a role.
Due to concerns about spread of WNS, the VDGIF has closed the caves on its wildlife management areas until more is known about the transport of the syndrome. The department will be asking private landowners with caves on their properties to consider closing their caves temporarily. Caving groups and individuals who enjoy caving are being asked to respect this temporary closure of Virginia caves and to suspend recreational and research caving activities until more information about the cause and spread of WNS can be determined.
The USGS National Wildlife Health Center is currently conducting experiments to determine how white-nose syndrome is spread between affected bat colonies and healthy bat colonies. Research is being conducted on soil samples to learn more about the fungus.
The scientific community is well aware that, with the rapid spread of WNS and the high mortality, answers to the mystery of WNS and solutions to address it are of the utmost importance. Because of the potential impact of WNS, the VDGIF urges cavers and cave owners to help Virginia's bat populations by reducing cave traffic until more is learned about this syndrome.