July 15, 2012

 

 White-nose fungus found in endangered Tenn. bats

A patch of white fungus, a telltale sign of deadly white-nose syndrome, is evident on the muzzle of an endangered gray bat (center) in Montgomery County, Tenn.
 
Posted on July 3, 2012 
 
Deadly white-nose fungus has spread to an endangered species of bat in Tennessee.
 
Confirmation this May of white-nose syndrome in gray bats in Hawkins and Montgomery counties is “devastating,” said U.S. Fish and Wildlife Service Director Dan Ashe.
 
The gray bat (Myotis grisecens) has been a federally protected species since 1976 and occupies a limited geographic range in the southeastern United States. It is the second endangered species of bat found infected by the white-nose fungus, which has been documented in seven bat species since its discovery in New York in 2006. The Indiana bat is the other endangered species affected by WNS.
 
The disease has spread into 19 states and four Canadian provinces, killing millions of hibernating bats. Bats with WNS may engage in unusual behavior during cold winter months, including flying outside during the day and clustering near the entrances of caves and mines where they hibernate. Bats have been found sick and dying in unprecedented numbers near these hibernacula.
 
Infected gray bats were discovered on two separate winter surveillance trips conducted by the Tennessee Wildlife Resources Agency and The Nature Conservancy. Biologists observed white fungus on the muzzles, wings, and tail membranes of several bats. Specimens were collected, and the disease was identified histologically at the Southeastern Cooperative Wildlife Disease Study at the University of Georgia and later confirmed by the U.S. Geological Survey’s National Wildlife Health Center in Madison, Wis.
 
“This species was well on the road to recovery, and confirmation of the disease is great cause for concern,” said Paul McKenzie, Missouri endangered species coordinator for the USFWS. “Because gray bats hibernate together in colonies that number in the hundreds of thousands, WNS could expand exponentially across the range of the species.”
 
McKenzie added, “The confirmation of WNS in gray bats is also alarming because guano from the species is an important source of energy for many cave ecosystems, and there are numerous cave-adapted species that could be adversely impacted by their loss.”
 
The potential impact of white-nose syndrome on gray bats is still unknown. Fungal growth was ob­­served on hibernating gray bats at both sites, but no other definitive field signs of the disease or deaths have been documented. The findings of these studies will be submitted to a peer-reviewed journal for publication, and gray bat roosts will continue to be monitored for any indication of deleterious impacts.
 
“We are not sure what this diagnosis is going to mean for gray bats and the spread of WNS,” said Jeremy Coleman, national WNS coordinator for the USFWS. “Increased vigilance and improved diagnostic procedures may mean that we have identified the very early stages of infection in a new species. It is also possible that gray bats have been exposed for a few years but do not succumb to the infection. Individual bat species appear to respond differently to WNS, and only research and time will reveal where gray bats fit on the spectrum.”
 
The USFWS is leading a cooperative effort with federal and state agencies, tribes, researchers, universities, and other nongovernmental organizations to research and manage the spread of WNS. This includes the recent formation of the White Nose Syndrome Executive Committee comprising stakeholder organizations providing expert advice. Asked to serve on the committee, the AVMA is represented by Dr. Kristi Henderson, an assistant director of the Scientific Activities Division.