This Podcast Will Kill You - Ep 72 White-Nose Syndrome: How deep is your torpor?

Episode Date: May 4, 2021

A fluffy white fungus and a little brown bat. A deafening silence and an uncertain future. In this episode, we explore one of the most devastating wildlife diseases in recent times, white-nose syndrome. Since its debut in North America in 2006, this fungal pathogen has spread across much of the continent, leaving millions of dead bats in its wake. Why is it so deadly? Which bats are at risk? Where did it come from? And most importantly, what can we do about it? We attempt to answer these questions and more about this pernicious pathogen, and we are so delighted to be joined by Dr. Winifred Frick, Chief Scientist at Bat Conservation International and Associate Research Professor at UC Santa Cruz, who helps us take a closer look at the ecology and impact of this disease on North American bat populations. See omnystudio.com/listener for privacy information.

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This is Bowen-Yang from Los Colter Reesters with Matt Rogers and Bowen-Yang. Hey, so what if you could boost the Wi-Fi to one of your devices when you need it most? Because Xfinity Wi-Fi can. And what if your Wi-Fi could fix itself before there's even really a problem? Xfinity is so reliable. It does that too. What if your Wi-Fi had parental instincts? Xfinity Wi-Fi is part-nanny, part-Ninja, protecting your kids while they're online.

And finally, what if your Wi-Fi was like the smartest Wi-Fi? Yeah, it's Wi-Fi that is so smart. It makes everything work better together. Bottom line, Xfinity is smart and reliable. You deserve the peace of mind of having Wi-Fi that's got your back. Xfinity. Imagine that. Hi, I'm Dr. Winifred Frick, and I started studying White Nose Syndrome when I was a postdoc, and I had been interested in population ecology and conservation biology of bats, but had not worked on hybrid-eating bats. And I got introduced to the topic of whiteness syndrome by Dr. Tom Koontz, who was really the godfather of that biology in North America.

And he was a professor at Boston University. And he invited me to be a postdoc with him. And I went to visit him in the summer of 2009. and he had basically been studying Little Brown Bats in Massachusetts and New Hampshire for decades, really, like had a whole system of a set of maternity colonies, which is where females come to raise their pup that he had trained graduate students and also had a field camp with undergraduate students. So these were like, you know, this was his system and really these bat colonies were, you know, part of his life. in his study system and really like old friends. So we, this was the summer of 2009. And so it was really early on in the WNS Episootic.

And we went on a tour, he took me on the tour of all these maternity colonies. And every time we would show up, instead of being thousands of bats, chattering and these are like an old barns and attics and things. And you should have been able to hear little, chitters and chatters of the females doing their social calls while raising their pups. It was just silence. And there were no bats there. And we'd get to the next date and there'd be the same thing.

And it was just, it was so heartbreaking. And I could see on Tom's face just the loss of these bats that he knew and had this long-term relationship with and that they were gone. And a couple years later, I was working in Virginia and doing underground surveys there. And it was sort of a similar thing where we would go underground with Rick Reynolds, who's the state biologist in Virginia, to these sites that he knew and he knew all the bats that should be in there and we'd get in there. And, you know, the main cavern where there should have been, you know, thousands of bats

was just empty. And it was that same look of just kind of disbelief and a sense of personal loss for these folks who had a relationship with these states and with these bats and seeing them just be gone. Wow. I just can't imagine the devastation. I know. It's so horrific. You just heard from Dr. Winifred Frick, and we are very excited because this is not the only time in the episode that you will hear from her. She actually was kind enough to spare some of her time to chat with us about white nose syndrome. Yes. Which is the topic of today's episode of this podcast will kill you. Hi, I'm Erin Welsh. And I'm Aaron Holmond Updike. And we did that completely backwards. I love it, actually. That was fun. It's fun to do things a different way sometimes. I know. I was like,

I don't know where we're going anymore with this. It's great. But we know where we're going with the topic of today's episode, which, as we mentioned, White Noe Syndrome, it is a wildlife disease. It's one of our first this season. I think it is our first one this season. Yeah. We've only done a few in our history thus far. So I'm excited about this one. Yeah. Yeah. But I'm very excited because, you know, this is the kind of thing where in grad school we learned about this as like a development. issue. Right. And it still is very much developing. I know. It's, I remember hearing a lot about it back in like 2013 when I first started grad school and I feel like I haven't been hearing about it as much lately. And so it was really great to do a nice deep dive. And I learned so much that I never knew. Like all I knew was, oh, the bats are dying. Yeah, exactly. It was really cool to do this deep dive and

I'm really excited to hear what you have to say. Oh, I'm excited to hear what you have to say. And I'm also excited, Erin, like you mentioned, to speak with Dr. Winifred Frick, who is incredible and a true expert on white nose syndrome and bats. So, very exciting. But before we get into all of that, we have some business to take care of. The most important business is quarantine time. It's quarantini time. What are we drinking this week? We're drinking. Wanging it. winging it because as we sat down to record we kind of realized that we had forgotten to name this quarantini we forgot it's fine we won it we won it um yeah i like the name though i love it it's perfect and i also like what's in the quarantini which is tequila of course because aaron tell us why we had

to choose tequila because without bats Tequila wouldn't exist. It wouldn't exist. Bats pollinate the agave plant, which is what is used to make tequila. So bats are crucial. Crucial for tequila. Yeah. But it's not just tequila.

You know, we spiced it up a little bit, added some peach green tea, some orange liqueur, some lemon juice. It's like really quite tasty and refreshing. Yeah, super refreshing. And the most important thing about this, and I don't know if it actually adds that much to the flavor, it might detract. But you rim the glass in powdered sugar for white nose syndrome. And we will post the full recipe for this quarantini, as well as the non-alcoholic placebo Rita on our website, This Podcast Will Kill You.com, as well as on all of our social media channels. All right. Other business that we always have to mention, we have a really great website,

This Podcast Would Kill You.com. On it, you can find a link to our Goodreads list, our bookshop.org affiliate account, our music. by Bloodmobile, transcripts of every episode, non-alcoholic episodes, all of our merch. Oh my gosh, there's just so much. Go check out our website. Yeah, I think that about covers it. So can we learn about White Nose Now? I would love to. Let's take a quick break and then dive into the biology. Dinner shows up every night, whether you're prepared for it or not. And with Blue Apron, you won't need to panic order takeout again. Blue Apron meals are designed by chefs. and arrive with pre-portioned ingredients so there's no meal planning and no extra grocery trip. There, assemble and bake meals take about five minutes of hands-on prep.

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This is a disease of hibernating bats that is caused by a fungus named pseudo-gymnoascus destructans. It's a very appropriate name. I'm just calling it. Oh, yeah. I think I just call it PD because I saw that pseudo-m and was like, I'll attempt that once if I have to, but that's it. Yeah, called PD for short. It used to be called geomyces destructans, but it's a different genus.

Anyways, PD for short. And I know that, Erin, you're going to talk about the discovery of this fungus and this fungal infection. But suffice to say, it is a very recent discovery. and has since been the cause of mass fatalities among hibernating bats in North America. This fungus is what's called a psychrophilic fungus, which means it's cold-loving. So it grows at temperatures generally between 10 and 15 degrees Celsius, and it really maxes out at like 20 Celsius. So it can't really grow above that, which for those of us in the U.S. is like 50 to 60. 68 degrees Fahrenheit.

And that aspect is really important, but I'm just going to put a pin in it for now, and we'll talk more about it later. So white nose syndrome was first noticed and named, I hope I'm not stepping on your toes, Aaron, in a picture, because this fungus literally grows on the skin of the muzzles, which are the tiny little bat noses, as well as their ears and wings. And it looks like a little white, fluffy Santa Claus beard, kind of. Yeah. Right?

Yeah. Yeah. At least one paper described it as, quote, the delicate, exuberant white filaments that obscure the muzzle. Wow, that's like so much, that's like such a cute description for such a horrible, like horribly devastating fungus. I know. It makes it sound really adorable. It's not. On the wings, where it also can grow, it looks kind of like a tacky white film almost.

But it also can present a lot more subtly with just kind of a loss of, you know how bat wings are kind of a little bit shiny looking? So infected bat wings can just kind of be a little less shiny or maybe just have small little tears in them that you wouldn't necessarily see unless you were looking very closely. And like we mentioned, as fluffy and cute as it might look in some pictures, this fungus is nothing of the sort. It's a lot more sinister. It doesn't just grow on the fur or on the skin where you see it. Histologically, if you look at the skin underneath a microscope, what you'll see are these fungal heifi, which we've talked about this season earlier in our coxidioidomycosis episode. It's the tree-like branching fungal form.

And so if you look under the microscope, you'll see these little tree-like fungal structures that invade the epidermis, the skin of the bat, and form these little cup-like erosions, these little ulcers that erode down into the underlying connective tissue. These fungal hyphy will invade and essentially can, like, replace hair follicles. They can invade sebaceous and apocrin glands. So these are like glands on skin. Like we have them too that secrete oils and sweat and things like that around the muzzle. And on the tips of these hyphy are one of the things that can distinguish them from other species of fungus. They have these conidia, which are spores, the like reproductive structures of fungus. And they're a little curvy little nugs.

They kind of remind me of like a malaria pair. parasite without the tail. I feel like that's what they look like under the microscope, kind of like a little boomerang shape. Right, right. Okay. So bats who are infected with white nose syndrome during hibernation, these are hibernating bats that are infected. By the end of their hibernation season, they generally appear very, very emaciated, they're starving, and very often they'll die. Infection intensity in affected hibernacian. Infection intensity, which is a new word I got to learn. I noted that in mine too.

I was like, I love this word. Hybrinacula is like where bats hibernate, like their caves and things. Infection intensity often reaches 100% by the end of a winter hibernation season. But actual mortality rates vary greatly by species, which we'll talk a lot more about. Right. So that's like the fungus and the symptoms. It's like we've covered a lot of ground. in a short amount of time.

And we now know that the end result is massive, massive die-offs of hibernating bat species. So the question that I want to get at in more detail in this biology section is how in the heck does this happen? Like, why are bats so susceptible to this pathogen? What bats are we even talking about? because the thing is, these skin lesions that I just explained, like it's just a mold that grows on the wings and the nose that doesn't sound that pathologic. But that's just what you see. It doesn't explain how these bats end up emaciated and dead, right? So to understand that,

there's two main questions that I'm going to try and answer. One is why these bats are susceptible to the fungus to begin with. And the second is what's going on within this infection that causes these dramatic effects. So first to answer the question of why are these bats susceptible, we'll focus on the biggest piece of the puzzle, and that is that White Nose Syndrome is a disease of hibernating bats. Right. So we get to talk about hibernation, Aaron, which is very thrilling because I, similarly to you, went on like a little bit of a deep dive into the evolution of hibernation.

And as I was putting my notes together, I was like, I don't know where to put this. So I'm just going to put it in a parentheses somewhere. In the fun facts section. Yeah, exactly. Oh, my gosh. The history section, yeah, just going to be sprinkling some fun facts in there because it's such a short history. So anyway.

I love it. I'm excited. I'm excited too. Let's talk about what hibernation actually is because I think a lot of us probably don't really know, right? You think of like a bear that eats a lot and then goes into a cave and hibernates. What does that mean? All right.

So during times of scarce food supply, aka usually winter, some endothermic animals, so like birds, mammals, not lizards and snakes, animals that control our own body temperature internally, that process requires quite a lot of energy. So one way that some endothermic animals cope with this food scarcity is by entering a state called torpor. I'm learning so many new words. It's so fun. And torpor is when these animals can decrease their metabolic demands substantially. Often body temperature drops substantially. And then heart and respiratory rates drop energy expensive. massively drops. So animals can then survive these periods of very, very low food supply just by living off of their stored fat, essentially. These torpor phases can last anywhere from six to 40

days, depending on the species. And hibernation makes up these torpor periods interspersed with a few hours or maybe up to 24 hours of, quote, arousal periods. where the animal often will bring their body temperature back up to normal or just move around, be a little bit more aroused than during torpor. But this is important. During these torpor phases, especially small mammals that hibernate, body temperature can drop as low as 10 degrees Celsius or lower. Mm-hmm.

That's 50 degrees Fahrenheit. It's amazing. That is so not normal for most mammals. Well, it's also interesting. Well, anyway, I'll get into the evolution of it later. Oh, I love it. It's really, really fascinating. So just to kind of put that in context, like what range are we talking about?

Human body temperature, we know, is like 36 Celsius 97, 97, 98 Fahrenheit. Little brown myotus, little brown bats. Normally their roosts are like around 100 Fahrenheit 38C, although I've seen some studies that say their body temperature can hop all the way up to 53 Celsius, 129 Fahrenheit. So they can be really hot and happy. But during hibernation, their body temperature drops down to within a couple degrees of their hibernacular, where they're hibernating, which is usually between 2 and 10 degrees Celsius. Right, which is right in the range of little old PD.

Oh, say that again, Eric? Perfect setting. Perfect setting for PD. Okay. So that's hibernation, torpor, et cetera. So how does that altogether make bats so susceptible? You already said strike one, right, that that is the perfect temperature for PD to grow. It is the temperature at which that fungus is most happy.

All right. Strike one. Strike two. In addition to the depression of a lot of different metabolic features like respiratory rate and heart rate, there's also a lot of evidence that among many animals, overall immune response is drastically lessened during hibernation. And this makes sense because most bacteria and other pathogens can't replicate very well at low temperatures.

Right. Yeah. So in general, animals that have been studied during hibernation have up to a 90% reduction in circulating white blood cells. 90%. I think I also remember reading somewhere that the hibernation, like basically the rabies virus goes quiescent. Like you can, it'll just stop during hibernation.

That is fascinating. It just stops replicating entirely. That's what I remember reading. This is like where I'm putting a citation needed to myself to go back and check. But I think I remember reading that, yeah. I mean, yeah, it makes sense, like that it would just persist but not still be replicating. Right. It's like actually, you know, what a cryogenesis? Right. Yeah. Oh my gosh. So much interesting work about hibernation. It's a totally separate changes. But so while these animals hibernate, even though there are periods of arousal, during that time, you do see white blood cell counts rise. But even during those arousal periods during hibernation, those white blood cell counts don't tend to rise back to like summertime normothermic levels. So that's strike two, right? Strike one, we're in the perfect temperature zone. Strike two, we already have a depressed immune system.

Strike three, though, is the clincher. White-nose syndrome affects the status of hibernation itself. And that is how it has the devastating effects on these bats that we see. Right. So now we can answer that second question. How does this skin infection, what seems to be just a skin infection, cause emaciation, starvation, and death? Spoiler alert. We don't fully know the mechanisms of this, but there's a lot of hypotheses and there's a lot of support for some of these. So I'll kind of go through what we know so far. First of all, bats that are infected with white nose syndrome arouse a lot more frequently during torpor than uninfected bats.

During these arousal periods, their body temperatures also increase to a great-year-old. greater degree than uninfected bats. Both of these things, more frequent arousals and body temperatures shifting at a greater rate, likely lead to an increase in metabolic demand. And the thing is, we don't fully understand exactly why it is that these bats are arousing more frequently when they're infected with white nose syndrome, but it's thought that it's very likely due to an increase in water loss. Oh, okay. Right?

So even though this is called white nose syndrome because of the white fluffy mold on the muzzle, it turns out that the major player in terms of infected area is actually the wings. So wings in a bat, besides being absolutely gorgeous, the structure. It's so cool. But besides that, they're also. a lot more than just skin. They're a lot more than just a bat's mode of transportation. They're a very physiologically active structure.

They're involved in gas exchange. They're involved in fluid balance. And so it's thought that fungal damage in the wings leads to an increase in evaporative water loss, which then leads to dehydration, fluid losses, electrolyte imbalances, and then increased arousal because of this water loss, which then that increase in arousal

leads to an increase in overall metabolic demand, which then leads to eventual starvation and death. Right. Yeah. There are other potential mechanisms at play. There's a lot of hormone changes that are seen with white nose syndrome infection. There are behavioral changes that are deemed sickness behavior where bats that are infected are more likely to hibernate differently, like off to the side and alone instead of clustering. Which is interesting in itself because of like transmission. Exactly, right. And so it's thought too that is this somehow like, is it a protective behavior for the bat

where they're like trying to not get more infected from others who might be around them kind of a thing? There's a lot of kind of behavioral research on it. But they also, when they do arouse, even though they arouse more frequently, their behavior is different when they're aroused. they have like reduced activity. They appear sick when they do arouse. And it's not really clear whether this is what exactly is kind of the cause of this. But we do know kind of this overall picture that this infection leads to increase in arousal,

increase metabolic rate, premature fat depletion, starvation, and death in a lot of species of that. In a lot of species. But not in every species. But not. And that is where this story gets so interesting and so complicated. So in North America, where white nose syndrome is a problem, at least as of today, 12 bat species have been found to be susceptible to white nose syndrome, and at least six other species have been found colonized with the fungus but without any real signs of disease or impacts on their population densities.

And way back in our Kittred episode, we talked with Dr. Tagan McMahon about how this is also true in amphibians. Some species of amphibians seem to be very tolerant of the Kittred fungus, while others are really massively impacted, right? And the same is true of white-nose syndrome. So while we can say right off the bat that, of course, it has to be hibernating bats, like hibernation is a big part of susceptibility, and not all bat species hibernate, although a lot do in North America more than half of the 47 species of bat rely on hibernation to get through the winter. But it's not just that because the fungus responsible for white nose syndrome has been found kind of all over Europe as well as the northern reaches of Asia. and not only does it exist in caves in hibernacula, but also on bats. And it also causes a very similar white, fluffy, moldy beard, but no disease, no white-nose syndrome.

Right. Just white noses. So the question of what makes some bat species very susceptible and some bat species not so susceptible is still a very open question. But there's a lot of people really trying to do the work to figure out what is the difference not only between the bat species in Europe and Asia that are very tolerant of this infection, but also even in populations in the Americas that have survived infection,

that have, you know, resisted this infection. There's a lot of potential theories out there. There's things like the specific, microhabitats of hibernacula and little itty-bitty differences between bat species in like the temperature of their hibernacula. There's a lot of cool work on the specifics of the physiology of torpor. So like how deep is your torpor or like exactly what temperature do you get down to? Things like that. I'm going to in my head is now how deep is your love, but how deep is your torpor? That's really good. And that's.

Our title. That's really funny. And also differences in immune response to kind of get at, you know, how are these different bat species reacting to this infection? Are they fighting it off? Are they just existing with it, etc. But what's so interesting is that there's also some studies from bats in Europe that suggests that the infection doesn't,

doesn't result in as much tissue damage because the fungal hyphi don't invade as deeply into the connective tissue. So literally doesn't cause as much damage to the wings. But the fungus does invade around the muzzle and it's not a difference in the fungus itself because PD strains from Europe are just as virulent in North American bats. Right. As PD strains from here. So it's really interesting and there's a lot of like very open questions still as to like what are these real mechanisms of tolerance and resistance in these bat species because if we can get at that then we could know more about maybe how to help protect other species. It's really interesting because I think that like it once again shows how little we know not just about our own immune system but the immune

systems of animals. Right. What the heck. It's fascinating. Yeah. Yeah. And I feel like one of the most exciting things about this, I mean, it's like horribly devastating, but I think it's really exciting because this is all happening right now. Like there are studies going on right now to answer these questions. Yeah. Speaking of studies going on right now to answer these questions, I think one of the biggest questions is like, what can we actually do about this? Right. And we'll talk a lot more about that in the current event section with our expert, Dr. Winifed-Frick. But I do want to just mention that people are doing so many different things to try and prevent the spread of this fungal

pathogen. So there are groups that are working on vaccines, oral, like virally vectored vaccines that are actually not dissimilar to the Johnson and Johnson and AstraZeneca COVID vaccines that are using a raccoon pox virus that expresses some proteins from this fungus. Ooh, interesting. Yeah, it's very interesting. It seems to induce an immune response, so that's very promising. How practical is the logistics of the distribution?

That's, I think, the biggest thing is the practicality of it. people are also working on the application of probiotic bacterial treatments using bacteria that we use for other like agricultural applications to help suppress fungal growth. Also the use of UV lights. Oh yeah. Isn't that so interesting? It turns out that this fungus has a mutation in its DNA that makes it highly susceptible to UV light, which is why it only grows inside of caves on bats. living inside of caves. So people have thought if we put UV lights at the entrances and exits of hibernacula,

that'll kill fungal spores on the bats as they fly in and out. What? Yeah. So there's a lot of potential. I think there's a lot of creativity in how people are trying to tackle this massive problem that is devastating North American bat populations and has been for over a decade. Yeah. So, yeah, that's the biology.

I didn't let you ask any questions, Erin. I feel like, I mean, I feel like you covered a lot of ground. And I think that the unusual thing about this particular topic is that because it is so new, we probably read all of the same papers. Oh, I'm sure. Yeah. Because, like, the literature is only at most, like, 14 years old. Right. Yeah.

Mostly, like 13 years old. So. Okay, well, take us through that 13 year history, Aaron, would you? I will. Okay. Let's take a quick break first. Anyone who works long hours knows the routine. Wash, sanitize, repeat. By the end of the day, your hands feel like they've been through something. That's why O'Keeffe's Working Hands hand cream is such a relief. It's a concentrated hand cream that is specifically designed to relieve extremely dry, cracked hands caused by constant handwashing and harsh conditions.

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Penny Mac Loan Services LLC, Equal Housing Lender, NMLSID 35953, licensed by the Department of Financial Protection and Innovation under the California Residential Mortgage Lending Act. Conditions and restrictions may apply. In the late winter of 2007, biologists from the New York State Department of Environmental Conservation set out to visit some caves near Albany, New York for just a routine survey of the hybridating bats that were there in the area. You know, things like how many bats are there? What caves are they in?

Where are they in the caves? How the hibernation seems to be going? You know, that sort of thing. And, you know, one of the things they were looking out for, of course, is whether there was anything unusual that seemed to be going on with the bats. And I'm sure that the biologists conducting the survey expected it to be no different from the countless other surveys that they had done in previous years. but the scene that greeted them when they first entered the caves and turned on their headlamps

was unlike anything that they had ever seen before. Maybe the biologist knew something was up during their approach to the caves when a few bats flew shakily out of the cave's entrance into the snowy landscape when instead they should be snugly hibernating inside. Or maybe the bodies of a few dead bats that dotted the ground a few steps outside of the cave's entrance. gave them some indication as to what they might find on the inside. But I'm sure nothing could have prepared them from the scene that awaited them inside the cave. Absolutely piles and piles of dead baths on the floor of the cave.

Others moving around, seeming to look for food, despite the fact that this was deep in hibernation season, and that there were no insects in the cold landscape for the bats to eat. And when the biologists moved on to other caves in the area, they learned that, unfortunately, this was no fluke. At at least three more of the caves where they surveyed, they saw similar devastation, with mounds of dead bats on the ground and more flying in the winter sun where they would not find any food, but rather would be easy pickings for birds of prey. I really can't even imagine how horrific a scene that must have been. No, there are, so in one of the books I read, or in one of the chapters of the books I read, there's a picture of it that is. I saw that picture. You saw it? Yeah. I mean, we saw it. We read all the same stuff. It was, yeah, it was, it was really, really awful, especially because before that I had only seen individual bats. Right. No, it's, with white nose. I mean, like, just to give you some idea over that, like in those four caves, bioling,

estimated that between 8,000 to 10,000 bats had died as a result of whatever was making them wake up from hibernation prematurely. But at that time, they didn't know what it could be. Was it an infectious disease? Was it some sort of pesticide? Was it habitat disturbance by humans? At the time that these first bat die-offs were recognized, the world was no stranger to massive, unexpected wildlife or plant losses, colony collapse disorder in bees, chitred and frogs, Tasmanian devil facial tumor disease, even the chestnut blight, among many other things. By the way, a lot of those are fungus. Not all of them, but a lot of them. Fungus. Yeah, interesting. And each one of these enormous mortality events illustrated

just how interconnected the world is, not just in observing the cascades within an ecosystem, but also in highlighting the roles that humans play, both as perpetrators of disturbance or as disseminators of infectious agents, but also as victims themselves. Things don't happen in a vacuum, as we are very fond of saying on this podcast. And the role that any organism plays in an ecosystem is never negligible. And the impact that a loss of a species or at least a loss of a population can have on an ecosystem can be very difficult to predict.

And if anything, these mortality events have highlighted how wildlife or ecosystem conservation isn't just some altruistic venture to preserve the charismatic megafauna of our planet. It's necessary for our own survival. So the discovery of thousands upon thousands of dead bats in some caves outside Albany was not just this tragedy that took place somewhere in New York. It rang some very big alarm bells across the globe. As we've talked about before on this podcast, bats are often unfairly scapegoated as pests, as bringers of disease, as whatever. But what is often not talked about enough is the absolutely integral role they play in the ecosystem, in our economy, and of course, our health.

There are over 1,400 species of bats worldwide. I was hoping you were going to list these numbers because I get so excited hearing about how many bat species there are. Press 1 to subscribe to bat facts. There's going to be a lot of them. Here we go. These bat species occupy nearly every environment that you can think of, and they display an incredible diversity in body size, in food preferences, in hibernation activity, in lifespans, social behavior, and so much more. And I want to give a shout out also to the amazing bat researchers who taught me so much about bats

at Stry, Smithsonian Tropical Research Institute in Panama. You know, it's very thrilling. I had a line that I didn't say in my little writing here. I was like, we're not bat biologists, but we have a lot of friends who are. We do. I was just going to say, you heard from one on the podcast before, Alex Trio, who provided your first-hand account for Dengay. Yeah, there are so many amazing bat researchers that I have encountered.

It was really, I mean, I still remember my very first year in Panama back in 2013, learning from a presentation by Rachel Page that there are more bat species on Barro Colorado Island, at least 74 species, which is this kind of smallish island in the Panama Canal, than there are in all of North America. Yeah. Like, what? It's so cool. Do you know what I learned researching this episode? There are no bat species in North America that are also in Europe. What?

Oh, that's interesting. Isn't it? Did you know that some bats are incredibly long-lived? No. Some live over 30 years. What? 30 years? Yeah, I think like at least six species live over 30 years.

And the oldest recorded bat lived 41 years. Stop it. I know. That's adorable. Did you know that the little brown bats are so little? They're only like five to seven grams? Oh, they're so cute. They're so cute.

And hold on. I also looked up the. etymology of the little brown bat and I got to find out what it is real quick. I love this. Okay, so the etymology of the little brown bat, which the species name is myodos lucificus. Lucificus means it's from the Latin light and to flee. So it's like it's a little light fleer, like to flee the light. Oh, that's so cute. It's very cute. Oh, what are some other bat facts? I guess I don't really have. That's like there are some more bat facts, but I I also want to shout out a Kentucky fact, which is that mammoth cave in Kentucky, is the world's

longest cave system with more than 400 miles of documented caves and probably much, like, more extensive. It's also the only national park in Kentucky. And it was also hit by white nose starting in 2014, bringing it back. Bringing it back. Okay. Bringing it back. But also, I'm not done with back facts. Okay, good. Articles about colony collapse disorder in bees often talk about like the number of foods that would be lost to us without bee pollination. But did you know that there are also many foods that bats pollinate? I did, but tell all our listeners. Bananas, avocados, mangoes are among over 300 fruit species that depend on bats for pollination and many others rely on bats to help spread their seeds,

like figs and cacao. And bats also play a hugely important and often overlooked role in agriculture through insect control. Pest management. We should pay them. I know. I read an analysis from 2011 that estimated that bats provide insect suppression services to commercial agriculture in the U.S. that is valued at on average 22.9 billion

dollars per year. That's a billion with a B. Yeah, that's a lot. Yeah, that's a lot. And if you've listened to some of our COVID episodes before, you know how we've talked about the importance of bat conservation for preventing spillover events. And we'll get into more of that later in our episode with our amazing guest. But the bottom line is that these bat deaths in New York would have far-reaching consequences. What exactly those consequences? What exactly those consequences would look like or how intense they would be depended, of course, on what on earth was responsible for the deaths. And once that was figured out, then the scope of the problem could be estimated and a plan for mitigating the spread could be developed. When the biologists had stepped into those caves, they noticed something striking about the dead bats that lay in piles on the cave floor.

Not just the sheer number of them, but also that many seemed to have this fuzzy white growth that was covering their nose and Some had patches like they're on their wings or torn wings. And it looked like it could be a type of fungus that could be the source of all of this death. But how would you even go about figuring that out? The identification was not necessarily an easy one because the places where these bats hibernate, the hibernacula, are full, chalkful of fungi. And probably most of them not fully characterized or not. never even like, you know, isolated before. Yeah, that's a good point.

And so culturing any one swab, even if that swab is directly from the muzzle of a bat, is likely to get you a lot of different fungal species. How do you know that you have the right one or the one that is causing the disease? Essentially, you follow coax postulates. Number one, you have to find the pathogen in just the disease but not the healthy individuals. Number two, you have to be able to culture the pathogen from an isolate collected from a diseased individual. Number three, you have to be able to take that cultured pathogen and inoculate a healthy

individual with it and then have disease result. And number four, you have to be able to then re-isolate that pathogen from that inoculated individual and culture it. It was pretty exciting to read papers that did those things. Yes. I have, I have, I never get to read those papers. I know. Yeah, and so that's exactly what they did.

So they actually tested this with these hibernating little brown bats. And so finally then, pretty, pretty soon after, it's not really a finally type of moment. They had the culprit, which as you mentioned, first was geomyces, destructins, now it's P. Destructins or PD. The fungus that was causing this growth, PD, hadn't been described previously. But as you mentioned, it did appear to be related to other fungal species that are also cold-loving. And in the group, it seems that some are pathogenic, but to plants and not to animals. So it seems that this one is the only one of the group, at least from one of the papers I read so far, right, that is pathogenic to animals. Okay.

So now that researchers had nailed down the pathogen responsible for this massive bat mortality, what were the next steps? Well, one was to figure out just how bad this was. Was it only those four caves outside Albany? Or were there bats dying all over the country or all over the world? Understanding the current distribution of this fungus would help characterize the scope, but it's also just a snapshot. You know, what's happening here at this moment in time? With mortality rates in the 90% range,

understanding how this pathogen spread and where it came from was, crucially important. White-nose syndrome, as it came to be known, was an emerging infectious disease. But an emerging infectious disease can be newly emerging, as in it's existed there before, but a recent mutation or a change in the environment has led it to increased transmission in a way to make it more lethal or something like that. Or it's brand new, introduced into a naive host population that has no evolutionary history with it. So why is it so important to make this distinction between whether a pathogen is introduced or re-emerging? Yeah.

And it's important for predicting how it's going to behave and how we try to control it. For instance, if the North American PD had been around for a long time in North America and a new mutation had led to these die-offs, then introducing it to Europe, for example, like somewhere it didn't exist, could be devalued. devastating for bat species there, who were presumably naive to that strain of the pathogen or the pathogen itself. But if instead it was introduced from, let's say, Europe, to North America, that could tell us about how the European bat species cope with this fungus. And in terms of management, understanding whether a pathogen is introduced or has existed before is also super important. So if the pathogen had been present in North America,

America before, then management practices might focus on the factors that influence the virulence of the pathogen. Because you're not going to control its spread. There's nothing you can do to control its spread because it presumably already has spread. But if it was new, then management techniques focus mainly on controlling the agents that spread the disease. But in the case of white nose, that would mean controlling the bats themselves, which is all but impossible. Yeah. Okay. So there are many different ways to test whether PD was introduced into the U.S. from somewhere else or whether it had just evolved to be more deadly. And I'm not going to go into all these different ways, but I will list the results or the evidence that points towards this being a newly introduced pathogen into North America. Excellent.

And I'm taking these points from a nature paper by Zucal-at-all 2016, by the way, just to give you. credit where credits do, even though we will shout out all of our sources at the end. Okay, so number one, none of the fungal communities associated with the North American bats and the places that they hibernate, the hibernacula, are closely related to PD. Number two, the isolates of PD in North America seem to be all clonal from one single genotype, suggesting, yeah, suggesting one introduction. Wow. So if it had been here a while, if it was something that had changed recently, we would see a lot more diversity. And number three, since the first known instance in North America, which as you mentioned was actually traced back to 2006 in a photo of bats with white nose, the distribution of white nose syndrome has followed a very clear invasion path.

And there's one exception to that, so asterisk. Number four, PD has been found in many European and some Asian countries, as you mentioned, including on bats, but without the super high mortality that we see here. Number five, experimental infection of North American bats with PD samples from Europe leads to disease or death. And number six, there's additional evidence that goes into like the fungal biology of it. So basically, like, there's the existence of different mating types of the fungus in Europe compared to just one in North America.

What? That's cool. Yeah, it suggests an introduction. Right. And so all of these bits of evidence put together, it's pretty suggestive that this fungus was introduced into North America from, you know, most papers, say Eurasia. And they estimate that because of the diversity of the fungus in different sites in Europe and Asia, and the fact that there appears to be either tolerance or reaverage.

resistance in the baths to the fungus there. It has probably existed in those places for millions of years. I'm just, I have, I have so many thoughts. I know. Yeah. I know. I mean, it's like, this is such an ongoing area. It's like, ah, you can only almost dig so far down the rabbit hole in some ways or down the bat cave. Oh, that's good. The oldest specimen of PD, at least that I came across was a 1918 museum specimen of a bat that had been collected in France. Wow. Okay. So, yeah. So how did it get to North America? We still don't seem to know, and it's possible that we'll never know the exact sequence of events.

There are several different possibilities from the transport of an infected bat from Europe to the use of contaminated field equipment in North American caves, from Tori, with contaminated clothing or shoes to maybe even, I saw one paper, suggest the import of European specialty cave-aged foods, like some cheeses. Wow. Yeah, yeah. So while all this research was going on in terms of understanding where this fungus came from and how it's being spread and what are we going to do about it, the pathogen can

continued to work. It continued to spread. It continued to kill millions and millions of bats. And that's actually the wrong tense, of course, because research is still going on and the pathogen is still continuing to spread. Since that first photo showing White Nose Syndrome in New York from February 2006, the disease has spread to 39 U.S. states and seven Canadian provinces. And while most of this spread is likely due to bat movement, some has been. been caused by humans, such as when it showed up in western Washington State, 1,300 miles or 2,100 kilometers away from the closest known contaminated site in Nebraska. And since showing up in Washington State, it has continued to spread out from there.

Is there a limit to the spread? Yes, there does seem to be, partly because hibernation, which is a key factor in the severity of disease, is not, as you mentioned, a trait shared by all bat species. Here's my rabbit hole insertion of the evolution of hibernation. Yes. I want to shout out a really interesting paper by Lazaroni et al from 2018. And in this paper, they talked about how the earliest bats, which evolved sometime in the Eocene around 50 to 60 million years ago, they weren't necessarily hibernators.

Like they probably weren't hibernators, but rather daily heterotherm. So they practiced this daily torpor. What? And that is sort of this midway between an endotherm and an ectotherm, meaning that like with this heterothermy or daily heterothermy, you can regulate their temperature themselves, but also allow the surrounding environment to regulate it. Right. So it was only later that hibernation and homeothermy evolved. And so this is also this long-time belief that the earliest mammals were homeotherms when, in fact, it might. actually have been at their heterotherms because that's sort of more in between.

Yeah. Yeah. Like reptiles, like reptiles and amphibians and homeothermy. Absolutely. And I never even thought about that as like hibernation as a kind of way of doing that too. Oh my gosh. Wow. Well, and it's so cool because all of these things too have been looked at as discrete traits.

But they're not. Like this exists on a spectrum. Right. the way that like body temperature regulation is managed. I went on a deep dive of bear hibernation and they barely even drop their body temperature. So they're able to do this amazing metabolic reduction without really reducing their body temperature very much. Ooh, it was really fascinating. And then there's like regional heterothermy.

So like different body parts. I mean, it's incredible. There is so much more to explore down these rapid holes. I found these bat caves. I love it. Anyway, okay, but not only do not all North American bats hibernate, which would reduce their susceptibility to the fungus, but also the environmental preferences of the fungus may prohibit it from establishing in some southern parts of the continent, for example. So like it hasn't shown up in Florida despite showing up in nearby states for at least seven years. But the worst may still not be over.

More than half the bat species in the U.S. are severely declining or are endangered. And other parts of the world where PD hasn't yet spread are certainly at risk, such as Australia. Even though some bats are displaying resistance to the pathogen, population recovery will take a very long time. Because this is such a new disease, like there's not really much more to the history than this. It's still being written. And so I'm very excited for our guest this episode since she's one of the ones doing a lot of that writing. Yeah. So I will stop here so that we get to hear what the expert has to say about the ecology and status of white-nose syndrome today.

Excellent. We'll let her introduce herself right after this break. Yes, I'm Dr. Winifred Frick, and I'm the chief scientist at Bat Conservation International and an associate research professor in ecology and evolutionary biology at the University of California, Santa Cruz. At Bat Conservation International, I lead our science department that's really focused on trying to use science and research to understand and solve the threats to bats and protect bats worldwide. So BCI is a nonprofit organization dedicated to ending bat extinctions worldwide. We implement endangered species interventions to try to protect critically, endangered species around the world. We also work on habitat protection and restoration, and we work on

research and development of scalable solutions to find conservation actions that can help bats. Awesome. Thank you so much for speaking with us. We're really excited. So we wanted to kind of start just by getting a sense for the status of white nose syndrome in the world today. So could you kind of Tell us the geographic distribution of white nose in North America and the overall effects that we've seen on bat populations so far, like the number of species that have been impacted and maybe some numbers in terms of population declines. Yeah. So white nose syndrome has spread from where it was originally emerged in upstate New York across North America. It is currently in over 30 U.S. states and seven Canadian provinces. and that is actually really coast to coast.

So about five years ago, the disease was detected in Washington State, but there's still some areas in which the pathogen that causes white no syndrome, which is a fungus, pseudogynobnoascus destructions, has shown up and invaded certain areas, but we have yet to see the manifestation of disease. But the impact that the diseases had has been really severe. So it affects hibernating bat species. And we have research that is just,

come out, showing that across the range of some of these species, the declines have been greater than 90% for some of our hibernating species, meaning that nine and 10 bats that we know about have died from this disease over the past decade. Yeah, it's hard to even, I think, imagine the scope of it or picture the scope of that. And so I don't have to tell you, but bats are integral in any ecosystem and declines in their numbers could have very widespread and cascading effects. So could you talk about what we've seen so far in terms of the impact that these bat declines due to white nose syndrome have had in the areas that have been hardest hit?

Yeah. So here in North America and in temperate latitudes, almost all of our bats are insectivorous. So bats are voracious consumer of nocturnal insects. And a lot of those insects are actually agricultural pests. It's well documented. The value that bats have to farmers. In fact, bats are eating insects that otherwise farmers would have to apply pesticides for. Bats have been documented to increase crop yields in places.

So one of the things that's been so intense about white nose is that we lost really common species, species that were highly abundant, right? And so we've seen a dramatic decrease in the number of bats that are out in the night sky, consuming insects and performing their ecological services. It's hard to quantify that kind of. impact because of just the complexity of the ways that we collect data that can kind of measure the interactions between bat abundance on the landscape, insects, and their impact. So at this moment, there aren't studies that really demonstrate the economic impacts from the loss of bats,

but the logic experiment of that is true. Yeah, that makes sense. And as you mentioned, we've seen such massive declines in bat populations. But we've also seen some population stabilize or even show, I think, the beginning signs of recovery maybe. So what do we know about the mechanisms of how these populations have persisted? And I'm also wondering, how has that been informed by what we've seen in Europe and Asia? Is there any reason for hope in this story? Or might we see a permanent reduction in population size? Yeah, those are great questions. And What we've seen is in certain areas, there seem to be colonies that seem to have stabilized, although they have declined precipitously. It's easy to kind of generalize across species.

And I should clarify that, you know, there's three species that have been most heavily impacted by White Nose Syndrome in North America, the little brown bat, the northern long-eared bat, and the tricolored bat. And then there's a fourth species, the Indiana bat that's actually was already listed as endangered in the United States. States. And in some places that species has seen, you know, on average 80% declines in colonies, but there are a few places where there still are very large colonies. And so some of the research that's been done on stabilization and maybe evidence of the starts of resistance have been on little brownback colonies in New York, where there are still a few very large colonies, although they're not as large as they once were.

And so I think there's still active research going on trying to understand both the mechanisms of resistance and or tolerance of populations persisting, but still getting infected. You know, one of the things that makes whiteness syndrome from a disease ecology perspective so pernicious is that the fungus that causes the disease can persist in the cave and mine habitats where bats are hibernating. And so when the bats return to their underground refuges to hibernate, they get re-exposed to the fungus. So it has an environmental reservoir, right?

And so pathogens that have an environmental reservoir can have a more serious impact on populations because once you see a big decline in the number of individuals, the pathogen is still there and available to infect the remaining individuals at the site. So that's to say that we're still trying to investigate what the last, long-term impacts will be, we have, there's some hope that there'll be environmental limits to the impact of the pathogen, meaning that we know that the disease affects bats when they're hibernating, and it takes a long time for the fungus to grow on their skin tissues and cause the physiological disruption that leads to mortality. And so in places where bats aren't hibernating for as long,

we may see less mortality, although we're still seeing high levels of mortality. And so, we're still seeing high levels of mortality across the range of where the fungus is currently spread. What we do also know is that the fungus is widespread throughout Europe and Northern Asia, and there, and bats also do get the disease, meaning the characteristic lesions, but we don't see the same level of high mortality rates in those places. So it could be that those populations have evolved some kind of resistance, or tolerance, and there's been a number of studies that have kind of tried to investigate those different mechanisms.

Gotcha. And so looking maybe ahead a bit in the future, what do we know so far about how things like climate change or this increasing land use change are likely to affect the distribution of white nose syndrome? And are there any concerns for its spread beyond North America in places that are still naive to the pathogen? Yeah, well, in terms of the spread, yes, there's been quite a bit of concern about other places that have temperate hibernating bats. And so there's been some surveys that've gone down on it in temperate South America, so in Chile and places. There's been some research

trying to understand what the risk to Australian bats might be. And, you know, we first discovered that the fungus is actually widespread in Europe. And that's where we assume that it come from, but then Dr. Joe Hoyt also did an extensive amount of work looking at presence for the fungus and evidence of the disease in Northern Asia and actually, you know, and also working with a set of collaborators kind of through basically a very extensive survey effort to understand both the dynamics and the environment and on bats in Asia and into Europe. So I think it's very important to be monitoring in these other places. and be able to act quickly if signs of the fungus get there.

We know that the fungus can persist on people's clothing and boots and other things that's quite possible that, I mean, that's how we assume that it got here was through, you know, some human activity. And then, you know, now that the fungus and the disease are in Texas and in caves where Mexican free-tail bats,

which are capable of sort of, you know, getting the fungus on them, they don't seem to be very likely to have high levels of mortality because they don't hibernate for extensive periods of time, but they're migratory and they migrate into Mexico. So there's Mexican collaborators, Dr. Rodrigo Medellín, who's working on doing surveillance for the fungus in Mexico as you move into more tropical latitudes, it's really in mountain areas and high elevations where you might get bats that might hibernate. That's, we'll use torpor periodically, but it's probably.

long-term hibernation that is really the risk factor. To go back to your question about climate change, you know, bats are choosing in temperate latitudes, bats are choosing underground environments that are very stable, that are thermally stable. I'm not sure how much climate change will influence underground conditions, although we've looked a little bit at the relationship between surface temperatures and underground temperatures. We know that temperature and humidity affect the fungus and may also affect the hibernation energetics of the bats. But I think probably where there's the intersection between climate change and disease impacts has to do with both the extreme weather events that disrupt ecology of species in various ways.

We saw huge mortality event in Texas during the big freeze this winter. So you've got these other stressors, right? These other big events that cause mortality or disrupt the food base. and if species are sort of at the limit and trying to persist and survive this devastating and difficult disease infection to then have the extra whammy of a big unseasonal storm that may delay spring or have some other kind of knock-on effect. Yeah, that makes sense. So kind of as you've been saying, and as we talked about through the whole episode,

this is a very ecologically complex pathogen. So what about other things? How do things like colony size or even social behavior? How do these kind of big picture things play into infection or extinction risk for different bat species? Right. So a little bit about the ecology of winter ecology of hibernating bats. In most of eastern North America, our hibernating bats are aggregating in large numbers and in multi-species aggregations, meaning you've got multiple different species using the same cave or mine to hibernate.

So these are really communities of bats that are in these underground spaces. And there's a lot of, there's variation in the social behavior during hibernation. There are certain species that form dense clusters where they're actually tightly packed together, most likely for thermoregulatory reasons. And then other species that are more solitary where they, you know, roost individually. throughout a site. So within one site, you might see tricolored bats that are sort of dotted throughout the cave or the mine, and then these dense clusters of something like an Indiana bat or a little brown bat. And what we found when we were first doing work on sort of the transmission

ecology of this disease is that the sociology, whether they were in dense clusters or not, didn't seem to have a big impact on the disease. And most likely that's because of the role, the important role that the environmental reservoir plays, that there's a lot of contacts between bats and between species in these underground environments. And so you can't necessarily predict the contact rates based off of the roosting behavior. Yeah, that's very interesting. And so now comes the question of, well, what do we do about it? And I know that there's been a lot of research on potential interventions from things like vaccines to bacterial control to using UV lights to combat white nose syndrome. So could you walk us through what interventions have the most

support or have shown the most promise? And what are people doing on the ground right now to control or manage the spread of this disease? Yeah, that's a great question. So from the very beginning, there's been a really earnest attempt to try to find solutions to this disease. And I think it's one of a really powerful example of researchers and managers coming together and working together to try to solve a difficult problem. There's an active research community trying to explore different solutions. And so Tony Rokey at the National Wildlife Health Center is working on a vaccine to see if that might help improve survival. There's been various different research in different kinds of treatments of things that you could actually spray on bats that might reduce the

infection or reduce mortality from infection. And there's also been a set of research that's focused on what we call sort of environmental treatments or environmental cleaning, which is ways that are focused on reducing the pathogen in the environment. You know, there's different pros and cons to different types of approaches. For treatments that require actually treating the bat, you've got the difficulty of trying to access a high enough proportion of the population that could be treated. Bats are incredibly sensitive to disturbance while they're hibernating. And so, and they're torpid.

They're not metabolically active. So you have to have a treatment that will work and that doesn't require lots of application and that also isn't super disruptive. And so, you know, thinking about treating the environment opens up some other kinds of because you could potentially do it before the bats return to hibernate, knock down the pathogen load. Of course, that's only going to be feasible in certain kinds of environments because if you're trying to do something that could reduce the fungus,

it might have non-target effects, and that's not going to be appropriate in cave ecosystems, but mines that are human-made environments, it might be possible. Lots of bats hibernate in mines. There's some folks that are working and trying to change them, microclimate conditions underground because there's evidence that suggests that bats that are in cooler, drier, hibernacula have higher survival rates. And so if we can maybe make the environmental conditions in terms of the microclimate less conducive to fungal growth and better for that hibernating energetics, that that could improve survival. At Bat Conservation International,

we've been involved in a number of different studies that have tried some of these different approaches over the years. And currently we're working on a different type of approach that we have nicknamed our fat fat project, which is focused on using some underlying research that shows that bats that are still surviving in places where white nose has been for a long time, show an increase in their body condition. They basically get fatter prior to winter. And then they have the fat reserves to basically, you know, withstand the infection and the metabolic costs that come with it. And so we've been looking at ways in which we can help bats fatten up before winter with the idea that increasing foraging efficiency. So bats do this thing where they go through

this period of hyperphasia right before they hibernate. And the most energetically intense time for female bats is when they give birth and they lactate. So they're ending the summer sort of having just gone through a really intense energetic period. And then they've got to rebuild and put on fat mass before being able to survive the winter. So they basically go on this feeding frenzy for a couple of weeks during what we call the fall swarm and they just pack on the fat. And so we're trying to target that time frame and we're building them bug buffets with using UV lights to attract nocturnal insects that they can feed at near their

hypernaculate. And it is pilot results. We're still working it out. But the pilot results are promising. We're really excited. And the nice thing about it is that it could point to long-term solutions of helping increase habitat quality in doing things to improve the underlying prey base that could benefit bats at the target areas where they want to improve their body condition before hibernation.

That is so cool. Bug buffets. I love it. But the beginning of the project is fat bats at the bug buffet. Yes, that's incredible. That's so cute. I also just love picturing bats, like getting extra chunky. before going into hibernation.

A bee bats are the best. They put all their fat on their butts and like, they're so chub-jub. Yeah. Oh, my gosh. I love it. So speaking of how adorable bats are, I'm sure you're aware how bad of a rap they often get unfairly in popular culture. And I think it's probably in part because they do have these associations with a lot of pathogens

that can potentially spill over into humans, including, of course, coronaviruses. And I saw at least one paper with some evidence that bats that were infected with white nose syndrome actually had higher viral loads of some coronaviruses. So could you talk about bat diseases like white nose syndrome and how the health of bats can be actually directly related to human health in the context of bat conservation? Sure. It's important to underscore that we still don't know how the virus that causes COVID-19 got into the human population. What we do know is that that can be some ancestral hosts for coronaviruses. So they carry closely related SARS-like beta coronaviruses, although the closely related

virus to SARS-CoV-2 probably diverged 40 or 50 years ago. And so there's still a lot of investigation as to how the virus that causes COVID-19 got into the human population. One of the things that's fascinating, though, is that bats are kind of like superheroes when we think about their immune systems. They are capable of carrying a bunch of different viruses and don't appear to get sick from them. And so there's lots for us to learn in terms of what sort of superpowers bats have in terms of their immune systems. And I think that was one of the reasons why White Nose Syndrome was so shocking and upsetting is that, like, there aren't that many diseases that we've seen really negatively impact bat populations in this sort of way.

There's a lot of research about bats and disease, but from all the viral research, it's more about how well they can sustain viral infections and not be pathogenic, right? But, you know, White Nose is caused by a fungal pathogen, and we've certainly seen other kinds of fungal pathogens decimate wildlife like. the kittured fungus and amphibians. I think one of the big lessons that we have learned from the COVID pandemic is just how understanding ecological integrity and protecting wildlife and protecting ecological systems is part of global human health. There's a growing body of evidence that shows that it's disruption and degradation of ecological systems that

increase the chance for spillover. And that's true across the board, not specific to bats. And so I think it's really important that we recognize and understand the ways that we can predict and prevent spillover events through conservation and protection of intact natural ecosystems. Yeah, absolutely. And so White Nose is obviously one enormous threat to bats in North America. And I was wondering if you could speak more generally about, some of the other biggest threats to bats, both in North America and maybe globally as well. And what can we do to sort of combat those threats? Yeah. So we recently did a review of the global threats to bats. And what we find is that,

so bats are an incredibly diverse order, right? They're the second most diverse order of mammals with over 1,400 different species. And a lot of that biodiversity occurs in tropical latitude. So iconically, we think about bats roosting in caves, but actually about 40% of the bat populations are cave roosting, but many, many species live in forest environments. In fact, many of our cave roosting species also depend on forests for foraging and habitat. And so the top number threat globally to bats is habitat destruction through deforestation, right? and then land conversion from agriculture. So land use, the intense impact that we have on the planet

in terms of just habitat destruction and degradation. Globally, other threats include hunting, unsustainable hunting. So bats are hunted in parts of Asia and parts of Africa. And if those hunting practices are done in a way that are unsustainable, we've seen certain species actually get hunted to extinction. And then here in North America, and really sort of growing around the world,

one of the major threats that's been identified is the impact of wind energy. So unfortunately, wind turbines kill bats and kill large numbers of bats. And so trying to determine ways in which we can support renewable energy in ways that does not cause biodiversity loss is really important. And luckily, there's really great research that shows that there are things that we can do.

We can actually prevent the turbines from spinning at low wind speeds during the seasonal migration and that dramatically reduces the amount of fatality. But getting some of those solutions adopted and part of standard practice remains a challenge. So lastly, too, like we know climate change is also an impact. So increase of severe storms. Roost disturbance is another threat. So going back to thinking about our bats that roost in caves, they can be really vulnerable to people coming in and either disrupting them on purpose because they are trying to like harvest

guano or do other things or not being aware that they're disrupting those populations. So in terms of what people can do, the thing, you know, it's wonderful when people share just how valuable and important bats are. You can also support groups that are working on bat conservation. And then I like to also promote that anything that you can do to lower your footprint on the planet. helps bats. So things that you can do to lower your carbon footprint and other things is that, you know, we're sharing the planet with other creatures. And if we can lower the type of impact we have, that benefits, benefits bats too. Well, that was just fantastic. I am still fan-girling. Absolutely. Really, really, really. Thank you so much, Dr. Frick, for taking the time to speak with us.

I have never gotten to speak with someone that I've read so many of their papers. Except maybe Peter Hotez. I was just about to say, maybe Peter Hotes. Anyway, that was absolutely wonderful. Thank you so very much. Well, should we go right to sources? We certainly should. So I shouted out a couple in the history section, but I will shout out just a couple more

that I thought were super great. So there's an entire book called Bats in the Anthropocene that is great, not just for like information about white nose, but about like other ways in which bats have been affected by humans and so on and so forth. And then I also want to shout out a very, very recent paper from March of 2021 by Hoyt at all called Ecology and Impacts of White Nose Syndrome on Bats. Tons of great info there. And also I have a bunch more sources, all posted on the website. Excellent. I want to mention that the white nose syndrome in Bats chapter from that book was written by none other than our guest, Dr. Winifid Frick, along with several other authors.

So thrilling. I also want to give a shout out to the whitenose syndrome.org website, which is coordinated by the U.S. Fish and Wildlife Service. Not only does it have a ton of very digestible information, they also have a ref works page that has links to over 500 peer-reviewed articles on white-nose syndrome and related things. So it's far more comprehensive. I opened so many papers that I didn't even get to from that ref work site. But I will also post all of the papers that I actually did use for this biology section on our website, like Aaron mentioned, this podcast with kill you.com. You can find the sources

for this episode and every single one of our episodes. Yes. Well, thank you again to our wonderful guest for taking the time to chat with us about white nose syndrome. Yeah. And thank you to Bloodmobile for providing the music for this episode and every single one of our episodes. And thank you to the Exactly Right Network of whom we are a very proud member. And thank you to you, listeners. We hope you enjoyed this animal episode. Yeah. Thanks for listening. Yeah. Well, until next time, wash your hands. You filthy animals. Success starts with your drive. An American Public University is here to fuel it.

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