Blood and Spore: How a Bat-Killing Fungus Is Threatening U.S. Agriculture

It's time to get acquainted with the dreaded "White-Nose Syndrome."


Less than two years ago, the deaths of bats by White-Nose Syndrome (WNS) was called the number one crisis affecting mammals in the US. Since then, this fungal disease has spread to 22 states and five Canadian provinces, and killed some seven million bats. Little brown bats, once America's most common bat species, have been hard hit, with mortality rates greater than 90% in many affected states, according to the US Fish & Wildlife Service (USFWS).

This shouldn't merely worry bat lovers; despite their rap as creepy bloodsuckers, bats play a multi-billion-dollar role in agriculture. But while the collapse of bee colonies across the US and Europe over the same period has grabbed headlines, the bat story seems to be in hibernation.

"The thing that is alarming to me is the fact that people are not alarmed," says Eileen Choffnes, Scholar & Director at the Forum on Microbial Threats at the Institute of Medicine in DC.

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White-Nose Syndrome, named for the white fungus (Geomyces destructans) it leaves on hibernating bats' noses, wings, and bodies, was first discovered in the US in a cave in the state of New York in 2006. The fungus is believed to have come from Europe where so-called Old World bats can be infected without any apparent ill-effects. Introduced into the North American bat population, though, it's proved deadly. The fungus causes the bats to wake during hibernation, possibly expend too much energy, and ultimately starve to death.

The fungus has rapidly spread from New York to caves and mines in other states and Canada, and there's no known cure for the disease. In some cases, 100% of bat populations have been wiped out in infected caves. Of 46 American bat species, says Ann Froschauer of the USFWS, 26 hibernate and so are at risk. The disease "could wipe out half of the bat species in the US," she says. "It's caused one of the fastest declines of wildlife that we've seen in the US."

Bats are crucial to the ecosystem. They eat disease-carrying insects like mosquitoes and feed on crop-damaging caterpillars and worms, contributing an estimated $23 billion (pdf) annually to the agriculture industry in pest control and pollination. They also, like bees, pollinate certain plants; certain species of bat are said to be so interdependent with the agave, the source of tequila, that one might not survive without the other.

Their loss is compounded by the fact that they reproduce slowly, producing only one pup a year, explains Choffnes, and at best five pups in a lifetime--assuming they survive to adulthood. What's worse, hibernating bat species have their pups while in hibernation. It's in these caves and mines that they are most at risk for contracting WNS. And then there are other bat enemies, including pesticides, pollution, wind energy, habitat loss, and various diseases.

Funding has come mostly through the USFWS, but experts say much more is needed. In 2010, Congress gave the USFWS $1.9 million to fight WNS through research and surveillance, and to pay for an annual WNS symposium. Froschauer says that since 2007, more than $12 million from her agency has gone into response, research and coordination on WNS issues. All but the original $1.9 million, however, were reallocated funds from existing budgets. 'The money available for addressing WNS is not enough," says Mollie Matteson, a conservation advocate with the Center for Biological Diversity in Vermont. "And as the disease continues to spread westward, it becomes even more urgent that federal funds are appropriated."

Some money has also come from other federal agencies, making for a total of oer $20 million devoted to WNS, says Jocelyn Ziemian, a policy specialist for Bat Conservation International. But, she says, the government would have done more if the disease affected animals such as livestock. "But in this really bad fiscal environment," she says. "We're lucky we've gotten what we have."

The money available goes mostly to response and coordination efforts, but bat advocates say more is needed for research. It's still unclear where exactly in Europe the fungus came from, and surprisingly little is known about bats, let alone about their ecology and the infectious diseases that harm them.

The agriculture industry, which relies on bats, has not so far offered much of its own money or lobbied for government funds. Experts say this may soon change. Big farming states in the south and midwest are only just beginning to feel the effects of the bat crisis. So far, northeastern and mid-Atlantic states have suffered the most, along with provinces in Canada.

But no one is holding their breath for more government money. Bats rank low on legislators' lists of priorities, particularly when education and healthcare are being cut. And although president Barack Obama's 2014 proposed budget calls for more than $6 million in new spending from various agencies to combat WNS, Congress could kill all of it.

Now is the time of the year when biologists are entering caves to assess what happened over the winter. So far, the news isn't good. In March, Georgia and South Carolina joined the list of states affected. Last month, nearly 10,000 bats were found dead from WNS in an abandoned iron ore mine, which was once the second-largest known bat habitat in Pennsylvania. And just last week, officials in Kentucky reported that bats in six caves in Daniel Boone National Forest had the disease.

With so many dead bats to examine, experts are getting better at understanding the disease and documenting cases. In the end, though, more funds are required, and fast. "We're learning a lot," says Choffnes. "But it may not be sufficient to eliminate the possibility of the mass extinction of bats in North America, Canada and Mexico."