The darkest night

Batman never faced a Riddler like this.

A disease that’s killed more than a million bats now threatens to spread to California. And UC Davis scientists are among those pushing for a national fight against the fungus.

“The disease causes a bat colony to be 99 percent diminished,” warned Janet Foley, a UC Davis professor of veterinary medicine and one of the lead authors on the new study calling for action. First observed in New York in 2006, the pathogen creates a frostlike fungus, known as white nose syndrome, on the wings and skin of hibernating bats.

The virus has spread across the eastern half of North America and, if it continues, will eventually kill all hibernating North American bats. “The fungus is an elaborate toxin so powerful it can etch glass,” Foley said.

A similar condition exists in Europe, but without the same level of lethality. In California, 23 bat species would be vulnerable. “We are watching to see where it goes next,” Foley said. “There may be some western barriers, but we don’t know.”

Caves are breeding grounds for the disease, due to the large numbers of bats and the cold, damp climate. Affected bats are roused early from hibernation and, as a result, use up vital stored-fat reserves by flying more, causing them to lose water quickly and also move to more exposed locations. The bats then starve, dehydrate or freeze to death.

Although it does not appear that white nose syndrome can be passed on to humans, if it does reach California, it could still have adverse public-health and agricultural consequences. As a keystone species, bats play an important role in consuming insects, helping to provide a natural insect repellant, and also to scatter seed.

“It is worse than West Nile [virus] for conservation,” Foley explained in an interview at her office at UC Davis’ Center for Vectorborne Diseases.

As a result, Foley and her co-authors are stressing the need for a proactive approach to white nose syndrome. Their action plan, recently published in the journal Conservation Biology, includes working groups to better analyze the disease, monitoring of bat populations and a network of volunteers to report any sick-bat sightings.

But for now, one of the biggest obstacles faced by scientists is lack of understanding about how white nose syndrome works.

“We need to know more, including full genome sequencing, so we can better understand it,” Foley said.