Lifeless Caves: The Bat Plague

Art by Reese Green

By Conor Doolin

It is believed that in 2005, a hiker visited a cave in Europe. This hiker unknowingly contaminated their shoes or clothes with a fungus known as Pseudogymnoascus Destructans (Pd). In 2006 a hiker in central New York introduced Pd to a cave system. Each year, Pd transmits White-nose Syndrome in new places across North America. As of 2020, it has jumped coasts and killed nearly seven million bats. To date, it has been identified in thirty-seven states and seven Canadian Provinces. The mortality rates are over 80% and in some cases 90-95%. It has only been found to impact bats that hibernate, which constitutes half of the forty-five bat species in North America. After human exposure, bats transmit the disease amongst each other. Caves themselves are sensitive environments. They are intertwined with underground aquifers and water systems. Caves provide homes for various endemic species, meaning the existence of a species is confined to one single geographic location. Additionally, caves are cold and damp places that maintain or expel very few nutrients. The fungus irritates the wings and skin of hibernating bats. This causes bats to wake up more frequently during cold months, depleting their fat reserves faster than can be replenished. Researchers extrapolate current trends within affected bat populations, and it is predicted every year White-nose Syndrome impacts bats it will take 100 years or more to offset. It would now take 1,000 years or more for bats to get back where they were ten years ago in North America.

Throughout human history plagues have disrupted social and economic stability. It is forgotten that our non-human counterparts have also been impacted, plague transmission exists amongst animals. Diseases can migrate between animal species and humans themselves. Pd is responsible for the contraction of White-nose Syndrome, yet species of bats in Europe developed natural immunity against Pd. This revelation is only possible through exposure over thousands of years. Pd is foreign to ecosystems in North America, so our domestic bats are disadvantaged. They have not been exposed to the selective pressure put on foreign bat populations until recently. Therefore, North American bats have not had ample time to naturally evolve against the deadly fungal killer. European bats that suffered from the effects of Pd were selected against, their gene pool shifted and reflected more beneficial alleles over thousands of years of evolution.

This plague is a concern for both bats and humans. Bats eat insects including moths and beetles. They are crucial for pest control and are estimated to save farmers $3.7 billion in crop damage every year. Additionally, bats help reduce the use of toxic pesticides. Bat extinction would create huge problems for the economy. Thankfully, there are ways to reduce the spread. Caves and abandoned mines could be protected and restricted from human travel. Also, decontamination mandation could exist on public lands. Unfortunately, there is no known cure currently, but new research suggests natural bacteria can inhibit fungal growth. Bats are important nocturnal mammals. They pollinate plants that only bloom at night and control insect populations. Bats are to thank for things like bananas, chocolate, and tequila!

Learn and contribute to the conservation and research efforts against

White-nose Syndrome

@ https://www.whitenosesyndrome.org/

References

Voigt, C. C., & Kingston, T. (2016). Bats in the anthropocene: Conservation of bats in a Changing World. Springer International Publishing.

Blehert, David S., et al. “Bat White-Nose Syndrome: An Emerging Fungal Pathogen?” Science, vol. 323, no. 5911, American Association for the Advancement of Science, Jan. 2009, pp. 227–227. science.org (Atypon), https://doi.org/10.1126/science.1163874.