SAINT JOHN, New Brunswick — A lethal and little-understood disease called white-nose syndrome is devastating the little brown bat population of New Brunswick.

And while bats may have a bad reputation in some circles, naturalists are warning their loss in New Brunswick could lead to the rise of destructive insect populations, especially in the agriculture and forestry sectors.

Donald McAlpine and Karen Vanderwolf, researchers at the New Brunswick Museum in Saint John, have discovered white-nose syndrome in the province’s most important over-wintering cave for bats, located in Albert County.

“It’s a mixture of little browns and long-eared bats,” McAlpine said of the roughly 6,000 bats that hibernate in the cave.

“There were over 1,200 dead on the floor and there were large numbers of bats that were visibly infected with white nose and many that were also actually dead, hanging on the walls. The ones that are infected, we don’t expect them to survive.”

McAlpine and Vanderwold made the grisly discovery two weeks ago.

Samples of the fungus from the cave have been tested and identified as the same strain that has been infecting bat populations in northeastern North America since it first was detected in a bat cave in Albany, N.Y., in 2006.

The discovery of the fungus in the Albert County cave is the first confirmation of the infection in New Brunswick.

“We knew it was coming,” said McAlpine, the museum’s curator in zoology. “But we were surprised by what we found in the cave. And we didn’t expect the disease to hit so hard when it first appeared.”  

Although recorded in Ontario and Quebec last year, no major die-offs of bats have been observed in those provinces. McAlpine said it’s a mystery as to why bats in New Brunswick should be hit so hard.

“Some of the modeling that has been done on declining populations as a result of this fungus suggests the little brown bat could be regionally extinct within 20 years,” he said.

“They don’t just eat bugs we don’t want around, like mosquitoes — they eat lots of insects that are agriculture pests and forestry pests, including the spruce budworm.”

The little brown bat is the most common bat in the province.

McAlpine said, at this point, there is no known way to stop the spread of the fungus.

However, naturalists and the province’s Natural Resources Department are asking people to stay out of caves and old mines that harbor bats in an effort to slow the spread of the spores and save the little winged mammals.

“The department will be working with the New Brunswick Museum to monitor and understand this situation,” Pascal Giasson, a biologist with the province’s Fish and Wildlife branch, said in a statement.

“We ask for the cooperation of New Brunswickers in limiting opportunities for cross-contamination to help reduce the impact of this fungus.”

Scientists do not know with any certainty how or why the fungus first appeared in North America in 2006. There is speculation it may have been inadvertently brought over from Europe, where bats have a natural immunity to the infection.

What scientists do know with certainty is the calamitous effect the new-to-America fungus has had on the hibernating bats of eastern North America.

In less than five years, white-nose syndrome has spread to 15 states, three Canadian provinces and is believed to have killed more than 1 million bats.

In one old graphite mine near Lake George, N.Y., the number of bats plunged from 185,000 to 2,000 in just three years.

The white fungus can be seen on the bodies of bats, especially around their noses.

McAlpine said no one is sure how it actually kills the mammals although it is believed it causes them to wake too frequently during hibernation and therefore uses up the small animals’ fat stores.

“The best hope now is that some portion of the population has a natural resistance and will survive and, over time, the populations will recover,” McAlpine said.

But he said it would take many years to recover since bats normally live a long time, over 20 years on average, and have only one offspring per year.