Dead bats tested here for mysterious syndrome
About 100 bats that died of a mysterious syndrome in the northeastern United States are being analyzed at the U.S. Geological Survey's National Wildlife Health Center in Madison.
The illness, which has resulted in the deaths of thousands of bats found since March at more than 25 caves and mines, is referred to as "white-nose syndrome" because of a white substance on the muzzles and wings of dead and hibernating bats.
The condition was first observed in February 2007 in caves near Albany, N.Y., by the New York State Department of Environmental Conservation. In early 2008, it was found in hibernation sites in New York, Vermont, Massachusetts and Connecticut.
The syndrome affects species including the little brown, northern long-eared and eastern pipistrelle bats.
"When we receive the carcasses, we examine them for signs of trauma before we look inside, to see whether a predator attacked or they might have been electrocuted. In the case of these bats, there was none of that," said Anne Ballmann, a wildlife disease specialist with the National Wildlife Health Center.
"They do seem a little thin, and some have white powdery substances on their muzzles. Some have reported it on limbs or tail flaps."
After that analysis, the bats are opened up and tissue samples obtained for virus and bacteria screening, and any fungus on the surface of the bats is analyzed.
"There is also some hypothesis that this may be toxic-related, so we are checking for pesticide residues," she said.
Some of the bats exhibited changes in the lung that have been difficult to characterize, and most had microscopic fungi on their bodies. The white substance may represent an overgrowth of normal fungal colonizers of bat skin during hibernation, and could be an indicator of overall poor health, rather than a primary pathogen, according to the National Wildlife Health Center.
The center has received bats throughout the winter season, since they have finished the hibernation season so are no longer found in caves.
People found very weak bats on the ground outside caves and then went inside to discover more of them dead, Ballmann said.
Some were also found roosting on the eaves of houses, which is unusual.
"No single cause has been determined, no causative agent," she said. "We are not the only institution looking, and we are getting ready to have a meeting to discuss this with other research institutions."
The use of pesticides, the impact of climate change and unknown pathogens are all possibilities, said David Blehert, head of diagnostic microbiology at the National Wildlife Health Center.
Some researchers have contacted scientists who are studying colony collapse in bees, to try to find out if the bat syndrome is somehow connected to the syndrome in which bees disappear and do not return to their hives.
"Bats eat a lot of insects, but they also tend to be pollinators because they land on plants," she said. "They do not feed on nectar in the United States, but in tropical areas, they tend to be more nectar feeders."
USGS National Wildlife Health Center
Scientists at the USGS National Wildlife Health Center -- Nancy Thomas, pathologist, left, and Dottie Johnson, technician -- conduct necropsy on a dead bat.
