A mysterious disease that has devastated North America’s bat population was traced…to a killer fungus imported from Europe, probably by an unsuspecting tourist.

Since it was first detected in New York state in 2006, the disease known as white nose syndrome has spread to 19 states and four Canadian provinces. It has wiped out entire bat colonies, killing as many as 6.7m animals, in the worst wildlife crisis in recent memory…

Now a team of researchers led by the University of Winnipeg have established the origins of the fungus, and determined how it kills – by rousing the bats during their winter hibernation season.

“The fungus somehow causes the bats to warm up from hibernation too often,” said Craig Willis, a biologist at the University of Winnipeg who oversaw the study by US and Canadian scientists…The extra effort, shaking bats from their torpor, exhausted the animals’ fat stores far too early in the hibernation season, causing them essentially to starve to death.

The most likely source of the fungus was human. The fungus, which has been identified, as Geomyces destructans, is known to have existed for years in Europe, but it does not kill bats there. In North America, however, the disease has wiped out entire bat colonies and spread as far south as Alabama.

The disease poses no threat to humans but it has knocked out a crucial part of the ecological chain. The average bat eats up to 1,000 of insects a year. Their loss could cost US farmers up to $3.7 billion a year…

The findings were seen as an important step to unravelling the mystery of the bat deaths…

The study offers no immediate fix. It is not clear how or why European bats developed resistance to the fungus or how it can be better contained. Researchers are not yet able to track the fungus to a particular country or cave in Europe.

At least it’s a start. Finding the broad source now aids in finding a spot source from which the ailment may be attacked from several directions.