Scientists have finally identified the cause of the mysterious condition that has decimated the bat populations in the northeaster United States. As it appears, a white, powdery-looking fungus that thrives in cave conditions has killed over 100,000 bats, at an unprecedented rate.

The collaboration between the U.S. Geological Survey, the New York State Department of Environmental Conservation, the New York State Department of Health and other similar organisms proved a success.  After two years of witnessing the bat population declining by 75 percent, the scientists have managed to isolate and identify the fungus.

The fungus, which was present on the muzzles, ear and wings of dead or dying bats, has been linked to their death, but is not necessarily the only cause, researchers said. “We found that this fungus had colonized the skin on 90 percent of the bats we analyzed from all the states affected by white-nose syndrome,” said USGS microbiologist and lead author of the study David Blehert. The findings appear in the online journal Science this week.

Scientists are still trying to find out whether the fungus had been introduced to the caves, or it already existed, and it started infecting bats as their condition weakened for some reason. After a detailed analysis of the data obtained, scientists concluded that the fungus was in fact recently introduced, and that before the white-nose syndrome, the mass mortality in bats was a rare event.

Due to the bats’ important role in insect control, plant pollination and seed dissemination, scientists are now working on finding a way to stop the fungus from spreading further. However, Blehert said, they first need to better understand the phenomenon, and assess the long-term effects on the North American bat population.