Mysterious fungus kills millions of bats across North America, researchers say

In the nearly two decades since white nose syndrome first appeared in an upstate New York cave, the fungal disease has swept through bat hibernacula from the Atlantic seaboard to the Rocky Mountains and into parts of Canada. Scientists estimate the toll in the millions, with dramatic local declines and localized extinctions reported in some winter roosts. The fungus, Pseudogymnoascus destructans, grows on the skin of hibernating bats, especially the muzzle and wing membranes, disrupting the animals natural torpor and forcing repeated use of fat reserves that many do not survive.

The ecological consequences of such losses are broad. Bats are major nocturnal insect predators and perform ecosystem services that include natural pest control for forests and croplands. Entomologists and economists warn that fewer bats could mean higher insect abundance, increased pesticide use and elevated costs for farmers and foresters. Wildlife biologists also note the intrinsic conservation value of bats and the cascading effects their disappearance could have on cave ecosystems and nutrient cycles.

Researchers have responded with an array of approaches drawn from field ecology, microbiology and veterinary science. Surveillance teams monitor hibernacula for fungal presence using swabs and genetic tests, mapping the pathogen s spread and identifying hotspots. In laboratories, scientists culture the fungus and study its physiology to find vulnerabilities. Experimental treatments are being trialed, including antifungal compounds, beneficial bacteria intended to outcompete the fungus on bat skin, targeted ultraviolet light treatments in caves, and vaccine strategies aimed at stimulating immune responses before hibernation.

Field trials present methodological and logistical challenges. Manipulating winter roosts risks disturbing hibernating bats and causing additional mortality. Researchers therefore balance the need for rigorous tests with strict protocols for minimizing disturbance, including timed access to caves, protective decontamination for personnel and noninvasive monitoring technologies such as infrared video and acoustic detectors. Captive studies allow controlled evaluation of treatments but raise ethical questions about keeping wild animals in laboratory settings and the feasibility of reintroducing treated individuals to the wild.

Conservation managers have implemented immediate measures to slow transmission. Many caves and mines remain closed to the public, and agencies promote decontamination procedures for gear and clothing. State and federal wildlife agencies coordinate surveillance and recovery planning, while non governmental organizations support public education and funding for research.

The path forward involves trade offs. Aggressive interventions could save populations but may carry unforeseen ecological side effects in complex cave microbiomes. Limited conservation dollars force difficult choices about which species or sites to prioritize. Nonetheless, scientists emphasize that early detection and coordinated action can reduce further losses, and that continued investment in applied research offers the best hope for restoring vulnerable bat species.

As white nose syndrome continues to reshape mammal communities across North America, researchers say the crisis underscores the need for rapid translation of laboratory discoveries into safe, scalable field solutions and for sustained public and political support to preserve a group of animals vital to both natural ecosystems and human economies.