White-nose syndrome is a highly infectious fungal disease that is killing bats across the country. This disease is named after the presence of white fungus on the muzzles, wings, ears, and feet of infected bats. First found in North America in the winter of 2006-2007, white-nose syndrome has spread significantly over the last decade. The first bats with white-nose syndrome were found in a cave in Albany, New York, and now the disease can be found in most eastern and Midwestern states as well as in Washington. It is estimated that around 5.7 million bats in the eastern United States have died from this disease. Certain species are more vulnerable than others, including the Indiana bat (Myotis sodalis), an already endangered species.
What causes white-nose syndrome?
The fungus Pseudogymnoascus destructans causes white-nose syndrome. The fungus can only grow in cold temperatures with optimum growth taking place at 12-14° C (54-57°F). This makes hibernating bats, whose body temperature can reach as low as 2-14°C (36-57°F), extremely susceptible to this fungus. When this fungus grows on a hibernating bat, it creates significant lesions that lead to the physiological responses that eventually kill the bat.
Although not completely understood, it is believed that the fungus-induced lesions lead to the early use of fat stores necessary to survive hibernation. When the fungus creates lesions in the wings of hibernating bats, the transport of blood through the wings is degraded. Since the transport of blood is essential for the movement of carbon dioxide out of tissues, the reduction in blood flow results in a build up of carbon dioxide within the body. Elevated levels of carbon dioxide in the body create respiratory acidosis (decreased blood pH). The bat responds to respiratory acidosis by hyperventilating, which can wake them up from hibernation. Waking up from hibernation too early is bad for bats because waking up utilizes a lot of energy, depleting fat stores necessary to survive till spring. When these bats wake up too early, they use up their stored energy and cannot replenish that energy because their main food source, insects, are unavailable in the winter. When bats run out of their energy stores mid-winter they die. This is believed to be why up to 90-100% of bats in certain caves have died.
How can you help?
The U.S. Fish and Wildlife Service has listed these recommendations to help limit the impact of white-nose syndrome:
- Avoid possible spread of Pseudogymnoascus destructans (this fungus is most often spread from bat-to-bat contact but can also be transferred to other caves on clothing, shoes, equipment, etc.)
- Avoid disturbing bats
- Be observant (report signs of white-nose syndrome)
Other recommendations and information can be found at: www.whitenosesyndrome.org
References
Glaeser JA, Pfeiffer MJ, Lindner DL (2016) White-Nose Syndrome of bats. Mushroom The Journal of Wild Mushrooming. 31(114): 42-47.
Titchenell M (2012) White-Nose Syndrome A Deadly Disease of Bats. The Ohio State University Extension.
White-nose Syndrome. U.S. Fish and Wildlife Service. www.whitenosesyndrome.org. Accessed 15 April 2017.
Photo Credit:
Bat Remains: Ann Froschauer/U.S. Fish and Wildlife Service
Bat with white-nose syndrome: West Virginia Department of Natural Resources