In the winter of 2006, biologists in New York State discovered large numbers of dead bats while surveying hibernating colonies in caves and abandoned mines. The cause was identified as a new fungus, Pseudogymnoascus destructans, responsible for white-nose disease, which has since spread to 40 states and nine Canadian provinces.
DeeAnn Reeder, a disease ecologist at Bucknell University, described the situation as “the most dramatic wildlife mortality event that’s ever been documented from a pathogen,” estimating millions of bat fatalities.
Recent developments have brought some optimism to bat experts, who have found methods to protect bats and assist infected animals. However, a new study suggests the potential for a second wave of white-nose disease could threaten North American bats.
The study unveiled that Pseudogymnoascus destructans consists of two species native to Europe and Asia, with only one currently in North America. The introduction of the second species could trigger another epidemic.
Sébastien Puechmaille, a researcher from the University of Montpellier, noted that he has been studying this fungus since its emergence in North America. Discussions with American colleagues about the concerning situation led to his commitment to understanding the pathogen that has caused mass die-offs among bats.
Research indicated that the fungus evolved in Europe and Asia, where it coexisted safely with bats. In contrast, North American bats lacked immunity and suffered severe consequences upon exposure, leading to many starving during winter.
Puechmaille coordinated an extensive genetic survey involving over 5,400 samples to trace the fungus’s origins. The findings revealed that all North American samples are nearly identical clones, suggesting a single introduction event prior to the disease's discovery in 2006.
The study pinpointed an 18-square-mile area in Ukraine as the likely origin of the spore responsible for the North American epidemic. It is theorized that American spelunkers may have inadvertently transported the fungus back to the United States.
The research indicated that Pseudogymnoascus destructans comprises two genetically distinct groups, Pd-1 and Pd-2, which diverged approximately a million years ago. While Pd-1 has been the sole cause of North American outbreaks, the potential arrival of Pd-2 poses significant risks to bat populations.
Puechmaille emphasized the importance of establishing conservation policies to prevent the spread of this second fungal pathogen, urging that cave equipment should not be moved between countries without proper disinfection.
He cautioned, “A single spore is enough,” highlighting the need for heightened awareness and precaution in preserving bat populations and preventing future outbreaks.