As they hibernate in dark, frigid caves, a mysterious fungus creeps on them, creating a white patch around their nose, wings and ears. The fungus wakes them early from hibernation, creates starvation, wing damage and a quick death.
To date more than one million bats have perished. Why remains a mystery.
McMaster’s Jianping Xu, an associate professor of biology and member of the Institute for Infectious Disease Research, is collaborating with leading microbiologists across North America to understand the Geomyces destructans fungal disease (or White Nose Syndrome, called such as infected bats have a very white patch around their nose). The fungus was first discovered in 2006 in caves and mines around Albany, New York and is now rampant around northeastern U.S., Ontario and Quebec.The most common species, the little brown bat, is on the verge of extinction.
To understand the fungus, its origin and spread, researchers analyzed the DNA of 16 strains of the fungus from caves in seven New York counties and one from Vermont. They then compared Geomyces destructans with a closely related species called Geomyces panoma and found that all the Geomyces destructans strains were genetically identical. This led them to believe that the White Nose Syndrome in northeastern North America is caused by a single strain that has undergone rapid dispersal to cause all of the bat deaths, from New York to Tennessee and from Oklahoma to Quebec.
"While the exact cause of death is still unknown, one of the things scientists have identified is the fungus can disrupt the tissue membrane in a whim and that makes them unable to fly effectively, and also makes them lose circulation, water, and the mechanism to regulate body temperature."
The researchers have also discovered a treatment that could help preserve the species. They tested six strains of the fungus against drugs already used to treat people and animals for ailments ranging from athlete’s foot to life-threatening infections. The drugs include fluconazole, the most widely used antifungal drug.
Xu says researchers are working quickly to understand White Nose Syndrome before it is too late. "While bats are carriers of certain disease, including rabies, the loss of the bat population would be detrimental," he says. "There are several serious consequences. First, many plants require bats for pollination, and second, bats are predators for insects such as flies and mosquitoes and many of those insects are vectors for human disease like West Nile and malaria. If these bats are gone there would be no natural predator, so we would probably experience an increase in insect-borne infectious diseases."
While researchers have made headway, little is known about the fungus. "Scientists do not know how the fungus affects bats at the cellular and molecular level, where it comes from or even how it reproduces in nature or in bats themselves," says Xu. "But by having the opportunity to collaborate on an international scale with researchers looking at fungal population biology and epidemiology, it allows scientists to work quickly to understand this fungus. There are no boundaries to understanding disease when you have a global perspective."
The findings appear this month in Emerging Infectious Diseases.