Spread of White-Nose Syndrome, Geomyces Destructans

In a previous article, I discussed White-Nose Syndrome, Geomyces Destructans, a disease that had manifested in bat populations in the northeastern U.S. In summer 2009, caves were voluntarily closed to humans in many states as far west as Indiana and Kentucky in an attempt to control the spread of the fungus, and to allow scientists a chance to learn more about the disease. As the 2010 spring reports come in, all caves in Missouri are closed to spelunkers, except four tourist caves which are deemed low risk. This represents a major spread of the disease westward.

Dr. Jonathan Sleeman, Director of the U.S. Geological Survey's National Wildlife Health Center in Madison, WI, confirmed in a May 19, 2010 news release that a live bat in northwestern Oklahoma is infected with the fungus. Prior to this discovery, an infected bat in eastern Missouri was believed to mark the farthest the fungus had spread. The Oklahoma bat is a different species, and over 450 miles farther west, indicating that the disease is spreading much more rapidly than anticipated. Until now, all the infected bats have been east of the Mississippi River.

Humans do not contract the disease. Experts believe it spreads from bat to bat by contact. There is no indication that any other animals can contract it. Not all species of bats are affected, but bats that become infected always die. The Indiana bat is one of the hardest hit species. Indiana bats once numbered in the millions, but the species has been endangered since 1967, when the population was less than 900,000. By 2004, before White-Nose Syndrome struck, the population had diminished to fewer than 400,000. Indiana is home to half of the remaining Indiana bat population, and the rest are scattered over 20 eastern states. The groups are migratory, moving between the same summer cave and winter hibernacula cave every year.

The White-Nose fungus was first discovered in New York in four caves in 2006. A white powdery-looking substance develops on an infected bat's muzzle, spreading to its ears and wings. The fungus interferes with bats' hibernation during the winter. In normal limestone cave hibernacula, bats cluster, or huddle close together for warmth. Their body systems slow, conserving energy while they live off their fat reserves. Bats with White-Nose wake up and fly out in cold weather in the daytime, using up their fat reserves. With no insect activity and no food, they die from starvation. Some eastern hibernacula have mortality rates between 90 and 100 percent.

What good are bats? Read more here.

Sources:
CaveBiota: http://www.cavebiota.com/wns.htm
Missouri Department of Natural Resources http://www.dnr.mo.gov/newsrel/nr10-280.htm
Fish & Wildlife Service: White-Nose Syndrome http://www.fws.gov/WhiteNoseSyndrome/index.html
Bat Conservation International http://www.batcon.org/