Bats and COVID-19
Bats have been singled out as one possible source of the COVID-19 virus that has spread around the world. But there is a lot more to the story.
First, North American bats do not carry the Covid-19 virus. Bats, on the other hand, could be at risk of catching the virus from humans, one of the reasons we have temporarily stopped the parts of our field research that involve handling of bats. We are working to learn more about this risk to our bats before we resume this aspect of our work.
Bats have been singled out in some media stories and social media posts as a major source of viruses, but relatively speaking, bats are actually no more likely to pass a disease to humans than any other species. What makes bats somewhat unique is their wide species diversity (second only to rodents), which does lead to them potentially hosting a wider variety of viruses. The more species that makes up an animal group, the greater the diversity of viruses that could possibly ‘spillover’ to humans. A case in point is rodents: Rodents (which are completely unrelated to bats) are the most diverse group of mammals and thus have been responsible for many human illnesses or diseases such Bubonic Plague. But while bats play host to viruses, this does not automatically make them a source for human disease. Rather it is when we disturb bats through activities such as habitat destruction and wildlife trade that the risk arises.
Bats possess a fascinating ability to live with some viruses and show no clinical signs of disease, while the same viruses cause serious sickness in other mammals. This holds true even for viruses like Ebola, Marburg, and certain coronaviruses. This ability suggests the bats may hold the key to combating viral infections in humans. University of Saskatoon researcher and WCS Canada research collaborator Dr. Vikram Misra explains that bats keep the viruses in check via their unique immune system. But if a healthy bat is put under stress, its immune system is thrown off balance leading to viral multiplication in the bat and greater potential for viral shedding and subsequently, spillover, or the transmission of a virus between species. Of course, bats also play a huge role in controlling insects that can be vectors for other diseases.
While the horseshoe bats found in China are the likely ancestral host of SARS-CoV-2, we still don’t know how SARS-CoV-2 spilled over from bats into humans and if an intermediate animal host was involved. Two major pathways known to trigger spillover events between wildlife and people are the wildlife trade and environmental degradation. As new data emerge, now more than ever, we are recognizing that human health and planetary health are intertwined and that wildlife conservation is part of global health solutions.
Bats in North America are already facing a disease crisis of their own – white-nose syndrome. This disease (which poses no threat to humans) has wiped out millions of bats in Eastern and Central North America and is steadily spreading west.
These are tough times for bats as well as people, but we need to remember just how much we benefit from bats – from insect control and pollination to the fact that they are the planet’s only flying mammal. Bats are special and need special care.
The challengeA devastating disease called white-nose syndrome (WNS), which spreads between bats during hibernation, has led to millions of bats dying in eastern North America since 2007. This means we have lost major consumers of night-time insects, which could affect everything from forests to farms. The long-term ecosystem effects of such devastation are still largely unknown, but it is clear that we are rapidly losing fascinating animals -- our only flying mammal has more in common with grizzly bears than mice, living up to 40 years and producing typically just one young each year. Now, WNS is spreading west, threatening the rich diversity of bats living in western Canada (twice the number of species found in the east). WNS infected bats were discovered in Washington State in 2016 and were found in the spring of 2018 in Manitoba, Minnesota and Wyoming. This means the chance of it suddenly appearing in our western provinces is getting more and more likely.
What we are doing and why
WCS Canada’s bat research team is working with many different people and organizations across western Canada to identify threats to bats, research and monitor western bat species, and develop on-the-ground strategies for conserving bats. We monitor bat populations across BC and Alberta using acoustic surveys and other observations. For example, we are tapping the power of citizen scientists through our Alberta Community Bat Program (www.albertabats.ca) to find and monitor roosts and spread the word about the importance of bats to our ecosystems and our economy. Through the North American Bat Monitoring Program (NABat) we are coordinating many individuals who monitor grid cells providing information to assess changes in species diversity and relative abundance over time. The NABat network of local groups, government biologists, individuals, and scientists, which WCS Canada helped to establish and coordinates, can also serve as an early warning system for any signs of infected bats in the west. Similarly, the BatCaver program (www.batcaver.org), also launched by WCS Canada, involves the caving community in finding and assessing bat populations deep underground, while also informing cavers about how to avoid spreading WNS.
The knowledge we gain about bats in the west through these efforts helps us identify caves, old mines, trees, buildings or bat houses that function as key roosting habitats for bats in the West. Knowledge of such features provides early warning monitoring sites. We are also collecting information on the behavioural and physiological characteristics of western bats and the places they hibernate through the winter to help identify populations, species, and specific hibernacula that might be more likely to survive the arrival of the WNS disease. This WNS Survivorship Modelling team is an international collaborative effort among many biologists and organizations (www.science4bats.org).
With WNS steadily moving west, we are also looking for ways to help bats fight off the WNS fungus. We have been developing -- in conjunction with colleagues at Thompson Rivers and McMaster universities -- a preventative approach based on naturally occurring soil bacteria that can help protect bats from the WNS fungus (this work was featured on CBC's The National). These helpful bacteria that reduce the growth of the fungus that causes WNS, are naturally found on some bat wings in B.C. The goal of this project is to reduce the mortality of bats in western Canada by enabling bats at known maternity roosts (e.g., bat houses, building roosts) to arm their wings naturally with these bacteria. Strategically placed clay impregnated with anti-WNS microbes at the entrance of summer bat roosts allows a gradual and hopefully long-lasting change in wing microflora of bats. The more bats in the west that have high enough concentrations of anti-WNS wing bacteria, the more bats that are likely to survive each winter despite exposure to the WNS fungus. We are currently testing this probiotic approach on captive bats, and will apply the microbes to the floor of roosts of the most urgently at-risk bats,-- large maternity colonies in Metro-Vancouver. We are undertaking the field component of this cutting edge project in collaboration with University of B.C. Okanagan.
Finding and protecting key habitats: Unlike bats found in eastern North America, bats in the west -- particularly west of the Rocky Mountain Continental Divide -- do not seem to gather in large numbers in hibernation sites, such as caves or old mines. Double the number of species are found in western Canada, as compared to the east, with more than 16 identified to date. This diversity and lack of large gathering sites makes it more difficult to pinpoint key habitats. Field research to identify what species are found where and to learn more about their behaviours and habitat needs can help us build a survival strategy for western bats. In Alberta, BatCaver (a program of WCS Canada) has found many new hibernacula with hundreds of bats. Although this is a far cry from the thousands that hibernate together in eastern caves, such discoveries are increasing our understanding what bats need in winter, which in turn will help us recognize what landscape features that need protection.
Working with communities to help bats: Bats are often misunderstood, with many negative myths attached to our only flying mammal. Working with the Alberta Government, we are coordinating the Alberta Community Bat Program (www.albertabats.ca), informing communities about the importance of helping bats, and developing guidance for how to be ‘bat-friendly’. We are also helping to administer the BC Community Bat Program in the West Kootenay where we have our B.C. office. Currently, our focus is on understanding what role bat houses (bat boxes) play in bat conservation and we are leading the way in developing Best Management Practices for proper use of these structures in bat conservation across the continent.
Developing new ways to save bats: Together with researchers at Thompson Rivers and McMaster universities, we are developing a probiotic solution for white-nose syndrome that is showing great promise in being able to slow or prevent the growth of the fungus that causes this disease in bats. Our unique proactive approach targets bats in summer (thanks to our Alberta Community Bat Program and growing citizen databases like BatWatch.ca, and BC Community Bat Program [www.bcbats.ca] we are learning where bats hang out in summer in large numbers), making our approach one of the most promising options to date for reducing the impact that WNS might have on western bats.
Conducting and applying research to address urgent conservation concerns: We leverage our efforts through strategic collaborations with universities, agencies and other organizations that allow us to study and monitor bats. We work with researchers at many universities, including Thompson Rivers University, University of British Columbia Okanagan, McMaster University, University of Winnipeg, University of Saskatoon, and Trent University; and with government biologists in B.C., Alberta, Montana, Texas, Colorado, New Zealand, and more. We continue to seek collaborators and funders, as our urgent work continues. Main research projects include examining winter bat behavior, assessing species-specific risk of WNS, developing a tool to prevent WNS mortalities, and most recently, a critical examination of artificial bat roosts, specifically bat houses/boxes, and how they should be used in the face of climate change.
Our lead bat researcher, Dr. Cori Lausen, provides ongoing scientific expertise by working with agencies and on committees across North America, establishing new collaborations and working together to help bats (wcsbats.ca).