Three years ago, a few hundred bats were found dead in  hibernating caves in the northeastern state of New York. The event barely registered for some scientists. By the following winter, the death toll had risen to a few thousand bats, sparking concern among some experts. This year, the death toll could near a million, and has set off an alarm among scientists and farmers. The dramatic reduction in the bat population and and its potential extinction could have extensive health, economic and environmental effects. 

Bats are dying by the thousands

Hundreds of thousands of bats have died in the northeastern region of the United States.  According to some experts, the death toll is close to a million. The bats are succumbing to a disease called White Nose Syndrome, with a white fungus appearing on the nose, ears and wings of the bats.

"It is really unknown exactly what is causing the condition but in addition to the white nose by mid-winter these animals have lost most of their body fat," said Tom Kunz, an authority on bats at Boston University.

Bats that don't hibernate through winter risk dying

Injured or dead bat lay in the snow

In the northern regions, bats hibernate in caves and mines during the winter.  They accumulate fat during the warmer months and use the reserves in winter.  If they wake before the winter is over, they consume body fat and risk dying of starvation.
 
"Many of these bats with white nose have lost all of their body fat by mid-February and they arouse, they go out and fly around. People have seen them flying around when there is snow on the ground, when there is nothing to eat in the winter and their wings become damaged through frost bite," he said.

There are more than 1,000 bat species and they perform an essential service to the ecosystem, from pollinating to suppressing the insect population.

"We have shown that they can eat in a given night anywhere between one half to their entire body weight at night in insects. That converts into 630 tons of insects that a million bats would eat," Kunz said. "If we don't have them, those insects would still be out there and many of them are crop pest, they are garden pest. Without the bats, it means that farmers in order to maintain their economic advantage are going to throw pesticides out."

And pesticides would cost millions of dollars and have an impact on the environment and human health.

By the middle of May, when the number of dead bats became clear and the disease was spreading south, the U.S. government's Fish And Wildlife Service convened a meeting in West Virginia.

The scientists, park services and biologists who came debated what to do next.

"We recognize that this truly is a biological crisis," said Mary Parkin,  who is with the northern region of the Fish and Wildlife Service. "Because it is spreading so fast in an alarming rate."

Parkin says experts recognize the gravity of the situation, but so far, all they have is hypotheses about the illness and how it's transmitted. They know that if it continues to spread, some species could face extinction.

Steps taken to stop spread of infection

Entrance to bat cave

In January, the government barred humans from entering caves in the affected areas in a bid to stop the infection from spreading among bats. 

White Nose Syndrome is now in nine states and there is concern it could spread to the Midwest where huge bat colonies live alongside agricultural areas.  Latest reports indicate the fungus is already present in Canada.