A potentially widespread underestimation of a deadly fungal disease affecting bats in Western Canada is emerging from novel research. Scientists at McMaster University have found evidence suggesting the presence of Pseudogymnoascus destructans (Pd), the fungus responsible for white-nose syndrome, is more prevalent than previously indicated by standard testing methods. This discovery raises concerns for bat populations already vulnerable to the devastating effects of the disease, which has decimated bat colonies across North America.
White-nose syndrome, first detected in New York in 2006, has proven particularly lethal. The fungus grows on the skin of hibernating bats, disrupting their natural processes and leading to dehydration, starvation, and death. Some regional bat populations have experienced declines exceeding 90 percent, according to the U.S. Fish and Wildlife Service. White-nose syndrome poses a significant threat to the ecological and economic benefits bats provide, including insect control and agricultural support.
The McMaster team’s findings, published in the Journal of Fungi, highlight the limitations of current surveillance techniques. Researchers employed metagenomic sequencing – a comprehensive method that analyzes all genetic material in a sample – to examine bat droppings (guano), wing swabs, and fungal cultures collected from Alberta, British Columbia, and Saskatchewan. This approach differs from the commonly used quantitative PCR (qPCR) testing, which specifically searches for known genetic markers of the fungus.
More Widespread Than Previously Thought
The results revealed a striking discrepancy. Metagenomic sequencing detected evidence of Pd in all nine samples analyzed, including several that had previously been reported as inconclusive or negative using qPCR. “Our findings suggest the pathogen is likely more widespread than current monitoring indicates,” explained Jianping Xu, a professor in the Department of Biology at McMaster University and the study’s lead researcher. “The testing methods widely used across North America may be missing cases, meaning the spread of the disease could be underestimated.”
This isn’t simply a matter of refining detection methods; the genomic analysis also revealed significant genetic variation among the fungal strains found in Western Canada. This suggests the fungus may have arrived in the region earlier than official reports indicate, potentially as early as 2015 in Alberta, several years before its official detection in 2022 and public reporting in 2023. “This suggests the fungus may have been spreading quietly before we detected it,” Xu said. “That highlights the importance of strengthening surveillance in regions where the disease has not yet been formally reported.”
Tracing the Pathogen’s Origins and Evolution
The study reinforces existing research indicating that North American strains of Pd originated in Europe. However, the team’s analysis also points to rapid evolution of the pathogen within Alberta, with accumulating genetic mutations and visible differences in fungal growth characteristics. This evolution could impact the effectiveness of current monitoring and mitigation strategies.
The advanced sequencing also allowed researchers to identify the bat species present in each sample, including little brown bats – a species particularly vulnerable to white-nose syndrome – and other common western Canadian species. Western Canada is a biodiversity hotspot for bats, supporting the country’s highest bat diversity. Protecting these populations is crucial, given their vital role in controlling insect populations and supporting agricultural ecosystems.
Proactive Measures and Future Research
While qPCR remains the standard for routine surveillance, researchers emphasize the value of metagenomic sequencing as a complementary tool, particularly for early detection and in-depth genetic analysis. The McMaster team is actively collaborating with government agencies and conservation organizations to test a novel approach to combatting the disease: a probiotic treatment designed to enhance bats’ resistance to infection.
Field trials utilizing probiotic bacteria are currently underway in parts of western North America. The treatment is applied to bat boxes, allowing bats to acquire the beneficial microbes through grooming and contact with one another. Early results are promising, though researchers caution that the treatment’s effectiveness can vary depending on the genetic diversity of the fungal strains present. The Wildlife Conservation Society Canada is among the partners involved in these trials, working to implement and assess the probiotic treatment’s impact.
This research was supported by Environment and Climate Change Canada, and involved collaboration with the British Columbia Ministry of the Environment, as well as provincial agencies in Alberta and Saskatchewan, which provided crucial samples for analysis.
What’s Next?
The findings underscore the need for continued and expanded surveillance efforts across Western Canada, and beyond. Researchers are planning further studies to track the spread of the fungus, monitor its evolution, and refine the probiotic treatment strategy. The next official update on the spread of white-nose syndrome in Western Canada is expected from Environment and Climate Change Canada in the spring of 2024.
This represents a developing story, and ongoing research is critical to protecting bat populations and the ecosystems they support. Share your thoughts and concerns in the comments below.
