In Forward and Reverse: Understanding Zoonosis—Michelle Power—Department of Biological Sciences at Macquarie University in Sydney, Australia

Richard: Hello, this is Richard Jacobs with the Finding Genius Podcast. I have Michelle Power. She’s an associate professor in the Department of Biological Sciences at Macquarie University, and she works on the host Parasite Interaction and Wildlife with special interests and protozoan parasites and she’s in Australia. I asked her about koalas, but I don’t think that’s the wildlife she’s talking about, unfortunately, because I love them. But we’ll talk about her work. So, Michelle, thanks for coming.

Michelle: Great. Thanks, Richard. We’re not doing much on koalas, but lots of other wildlife that we might talk about.

Richard: Why do you like the ones that you work on?

Michelle: Yeah, so we work on a number of different species and from basically from land to the sea. So Tasmanian devils, which I guess are closely related to koalas, we’ve done some kangaroo work, seals, penguins, and of course the ever famous bats. So I’ve picked about four or five species and they’ve been selected for their connectivity to humans and the potential impacts that humans can have on those species relative to the transfer of parasites and other microorganisms.

Richard: So in the wildlife, where are they picking up these parasites when they’re in the wild or in captivity, particularly amenable or they become changed so that they have more problems with parasites?

Michelle: So it varies, again, with each of these hosts. So each of the groups that we’re looking at, we might take a step back. We look to work on a suite of different targeted organisms usually that are associated with the gut. So a couple of examples and some of the listeners may have heard of these. So cryptosporidium and giardia, they’re transmissible via water and so they travel through the environment and so when animals are when our wildlife species, they can pick them up in their natural surroundings, like if they’re in urban environments and drinking water or potentially when they’re undergoing rehabilitation when they’re coming to care after injury and then hopefully planned for release or also when they’re in captive environments for long term. But we’re a little bit more interested in those animals that are coming in and encountering humans. Now, organisms for a short period of time and then going back into the wild, all those that are in urban environments where they’re potentially exposed to the organisms we’re working on, all that might present a risk.

Richard: What is the number one animal that is of concern to you and why? And then I want to ask you what they get fed to with an hour or so.

Michelle: It comes down to me if I look, I have to say the number one interest for me is the bat. So the big fruit bats or the flying foxes, I’m particularly interested in them. So we know what we hear and we’re living this at the moment. But we hear that a lot of viruses have come from flying foxes. I’m interested in what we might term reverse zoonosis. So also organisms from us going into bats and some of these other species and then how that might impact them, but also how they might change and then come back into the environment and come back to humans. So organisms don’t just come from wildlife into us, they also go from us into wildlife and that’s kind of the crux and so all these any wildlife species that have this close connection to humans are potentially at risk from that from one of those events. So just generally, bats have a huge diversity of viruses and there’s a number of them that have when I think it’s important to note that when we say that they come from that while there are some that are transmissible now like rabies in Australia, we have an Australian bat that people can get a handle about. Or if I get a bite or scratch, some of these other viruses may have actually done the whole switch 20 years ago, 50 years ago, back in time. It’s not something that’s necessarily happening right now. So and I think that’s important to note. But I think also what’s interesting with bats is that we don’t really know why they have these highly diverse viruses and also why the viruses that they do carry don’t impact their health to the degree that we see in people and the other animals that those viruses impact. But they also do have. So I’ve mentioned. Some and some even bacteria, but they actually seem to be carrying some quite diverse and really interesting parasites and bacteria, so there might be something more going on in the in bats relative to a multitude of different types of disease-causing organisms, as opposed to just viruses or ecological role to the flying foxes servings of their fruit bats, which makes fruit.

Richard: But they pollinate as well.

Michelle: Yeah, so they’re pollinators and disperses so that there are huge important species in Australia at the moment relative to bushfire recovery and regenerating all our lost plants and ecosystems. But they’re also extremely urbanized. So I can go into the middle of the city here and there will be five, six thousand fruit bats just hanging in trees in our plants. So there’s this thing, they’re fantastic. There’s this nice, interesting kind of adaptation that they’ve been able to do in urban environments and obviously that leads to conflict with people as well relative to smell and noise.

Richard: So are there any people having them as pets?

Michelle: You’re not allowed to have them as pets. But they are one of the leading animals going into wildlife care at the moment in Australia as secondary fire-affected species, but also of from lost habitat, but also from heat stress. So they’re very susceptible to high temperatures and you probably see maybe some of the reports of the temperatures that we’re experiencing in Australia and I’m sure around the world, it’s getting warmer everywhere. But when it hits 42 degrees and I’m not sure what that is in Fahrenheit. So they literally can’t cope and they drop out of the trees and die. So we have thousands of bats going into care from heat stress and dehydration.

Richard: Are you focused on the parasites of the bats or what was your focus with them?

Michelle: Usually people focus on maybe one parasite or one disease-causing agent. But there’s been a shift now in thinking and knowledge and understanding that we need to be thinking about interactions within organisms relative to disease and also we’ve got a suite of organisms living inside us, our bacteria or our microbiome. They, too, can control the outcomes of a parasitic infection or and so my work now is looking at thinking about the context of infection and how that might occur in the bats. The questions that we’re asking is how that might actually drive the shedding of viruses and risks of emerging infectious diseases. So we’re looking at parasites. So I mentioned the two cryptosporidium and giardia, but we’re also looking at malarial parasites. So they carry parasites that are related to Plasmodium that causes malaria in people and they also carry some really interesting bacteria that are related to bacterial diseases or bacterial agents that cause disease in people as well.

Richard: So where do the flying foxes pick up these parasites and how do they affect them and what’s the consequence for them?

Michelle: So it’s early days with understanding if there are any kind of health impacts to them and some are just circulating. But when it comes to it, like amongst the thousands of bats here, unlike the microbes that live in caves here, the flying foxes and in other places, they live basically in the treetops. So they’re still in huge numbers in those colonies and so organisms would likely be easily passing and just generally occurring within a bat colony itself. But when it comes to the organisms that are related or that are likely coming from humans and this is more bacteria than the parasites, it’s likely that they’re picking those up from the environment, probably from drinking water. They will actually fly down and skim urban waterways and acquire that way. So one of the things I keep mentioning, bacteria, we’re actually specifically looking for antibiotic-resistant bacteria and so there’s a global issue where we’ve basically lost the ability of the arsenal of treatments that we have for bacterial diseases in people. Use of antibiotics has selected for resistant bacteria and now these are quite prolific in the environment and that’s the other arm of my research is looking at these resistant bacteria made it into different wildlife species and bats is one of the places where they actually have acquired quite substantial and interesting resistant bacterial lines.

Richard: What do you mean, resistant to some of these bacteria that it to the bats, or do you think the bacteria that affect us?

Michelle: Yeah, exactly. So what we would term human-associated bacterial species. So for example, E. coli and we know that human use of antibiotics has placed that evolutionary selection pressure on bacteria to acquire genetic traits to enable them to resist antibiotics. So they will carry those genetic traits with them, even though they are not necessarily being exposed to antibiotics and so now there’s a number of bacterial strains out there that just happily carrying the mechanisms that they need to resist antibiotics if they’re exposed to them and that’s the problem we have in human health and hospitals as well and that’s the best plan.

Richard: Do you think that they’re helping to spread these bacteria somehow or what?

Michelle: So that’s what we’re trying to understand. So it’s early days. So we’ve only been looking at the kind of dissemination of these resistant bacteria into wildlife. Well, in any great depth, at least for the last four or five years. So we’re actually trying to understand it. The interesting thing about these genetic traits is they can be shared between different species of bacteria. So we’re trying to understand if a bat or another wildlife species acquire a resistant bacteria from the environment, can they share those genetic traits with the bacteria that are actually residents inside, the more their natural, the naturally occurring microbiota or microbiome? And also whether they’re changing and coming back into the environment. But it’s too early to be able to answer those questions. I’d love to and we’re working towards that. But just a bit early at the moment, and we haven’t even gotten to the environmental sampling yet. We’re still just trying to understand what’s out there, what’s happening within the populations in those other species I mentioned, and then the next steps are to start looking at the environment and what’s coming back and potentially at risk of coming back into human populations.

Richard: So if you take particular bacteria that cause problems and people resistant one, it’s that bat, except that bacteria do appear to have any effect on the bat, any adverse effect? Does that alter it?

Michelle: So the first thing maybe we just might go back to those have any effect on the bat. So that’s at the moment. Again, I would say it’s still early days, but it doesn’t appear to be any in at least one day in bats that are in that way kind of trapping in their free-range populations when an animal comes into captivity because it’s injured and if it acquires one of those infections that’s at the individual level and could have a very different outcome. So I’m kind of generally more talking about now at the population level in free-range bats. A lot of the resistant bacteria, I guess resistant bacteria fall into two classes. So really, those that we know about cause severe diseases such as tuberculosis, mycobacterium, tuberculosis, or vibrio that causes cholera. All the friendly bacteria that we’ve carried for a long time, like our Ricola and Klebsiella that were what we would call opportunistic pathogens. So these bacteria typically kind of get cause disease or in the past cause disease in people who are compromised in some way or in hospitals and have like wounds or surgery. But it is these kinds of resistant friendly bacteria, they’re the ones that are now emerging and causing disease in healthy patients who might pick something up or healthy people who might pick something up just from the environment, from a cut and pick up one of these resistant bacteria. So that’s kind of the ones we’re looking at in the bats.

Richard: So this is just obviously complete speculation but if bats have a lot of viruses associated with them and in some cases, viruses can help bacteria acquire certain genes and help them transfer genes between bacteria. I wonder what would happen if you had a given bacteria that affects people. It goes into a bat now. It’s in a different environment with all these maybe novel viruses and maybe some of them can somehow prey upon that bacteria transfer of genes to it and interact with it and make it more virulent or different or require different traits of genes.

Michelle: Yes, that’s pretty speculative.

Richard: But I just imagine that this is like a witch’s brew of viruses and all kinds of other stuff inside them. I don’t know. I know they’re just living anywhere else.

Michelle: No, this is this is the problem that we face both in our research, but also with wanting to make sure that they did not seem like that. There are some interesting things happening in them relative to lots of different organisms, not just viruses. We need to remember that the reason these viruses are coming from bats and getting into us is that we’re encroaching on their environments and interacting with them. It’s not like they’re coming out to drop them on us. This shouldn’t demonize the bats. No, let’s try and not do that and it’s hard because we want to think about human health, but we also we share the planet with lots of different organisms, and yet we’re pushing that to the point.

Richard: What’s useful to understand about them, in your opinion, what is going to be some of the, there’s a lot I can hear. You’re at the beginning of the journey, but what do you feel is going to be the most useful questions that you can help answer about medicine, about parasites.

Michelle: So I think one of the risks of diseases spilling over and coming from bats is not going to go away, not unless humans do something to minimize invading their habitats connecting the connections with them. Unless that changes, we’re continually going to be exposed as other organisms that we have around us, like our pets and domestic animals. They’re also going to be exposed to the various organisms that bats carry. So I think the biggest thing is that is if we’re going to have more than high risk of more organisms spilling over and coming and causing issues, then we need to understand what the drivers are of that and how we can maybe put actions in place to stop that from happening. So, for example, as I said, if we have animals coming into care and some of the management practices that are they might be driving or increasing risks of organisms, bats or organisms that might evolve and change or spillover, then we need to act on those points. So working out, I think where the where the hotspots on offer for those risks of emergence and trying to manage at those sites, but then also working out what’s happening within the bat that causes that spill over so they don’t shed these viruses all the time. There’s something going on that that sticks on at a certain time. The viruses will be more prevalent in the environment and so I think understanding those and that’s basically the disease processes. But I think the second component to managing and understanding the risks from bats actually understanding how they cope with the multitude of different organisms that they have inside them that don’t cause them any harm.

Richard: So would you expect that the bats when they’re stressed, I would expect, I guess, the bats to, first of all, I guess, eat things they wouldn’t normally eat, go places they wouldn’t normally go because their physiology is stressed. Maybe the viruses that were once commensal with them now will try to jump out of them and leave them or cause them sickness. Same thing with the bacteria.

Michelle: So I guess it’s whatever shifts that balance. So if we think about we’ve got a lot of different organisms inside us and they have to go through a biological process to replicate and to produce and then they have to be excreted in some way. OK, so our immune systems and the immune systems, they’re turned off, they keeping that interaction, all that activity of those organisms at a lower level. But then you’re right, stress or something changing food source, it could be some sort of life history. It could be something happening within the colony like behavior dynamics, something like the flicks that switch and then those organisms get a hold, they can reproduce and then they start to be shared in the environment, which then increases. If people or other animals are in that kind of zone where those organisms are so, so, yes, so but understanding there’s a lot of people who have looked at various sorts of stresses to try and understand this with certain diseases but there’s still no clear cut answer as to when and why this happens.

Richard: Since the bats live close to a lot of people, I guess, in your area, but you said of this huge shock, a lot of them die. So imagine them like dying and laying on the ground and other animals eating them and then maybe diseases get transferred to the animals, etc.. I guess it is very important to understand where they go, what they do, what they interact with, what happens when they’re subject to these fires or there’s heat damage and they die, what happens to the spread disease, et cetera, et cetera, et cetera?

Michelle: Yes, exactly and that’s what I mean by understanding what those risk points are and how we can manage those things to prevent spillover. Because cities aren’t going away. Well, unless people unless we actually get rid of them, bats aren’t going away. So nor is that risk of spillover.

Richard: They better not go away because they pollinate a lot of crops.

Michelle: They do indeed.

Richard: Do people even know that they even pollinate?

Michelle: Yeah, well, there are a lot of messages and communications out there to try and get people to understand the important role they play as an ecosystem service provider. But people if you’ve got a thousand bats sitting in trees over your backyard and pooping all over your balcony, you think that’s the message that just generally that the bat community in Australia tries to push and there are spikes that sometimes the conflict will settle, but then something will happen and something will get paid or there be a little bit of an outbreak of one of the viruses that we have here or we have something like coronavirus and then that puts them back in the spotlight and researchers put them in the spotlight, too. 

Richard: With the shutdowns and everything, was there a change in the bat populations that they come out more like what would happen to them?

Michelle: So I probably can’t comment on the bat populations because basically they sit in the trees in the day and then at sunset they fly out to forage and you’ll see streams of them going everywhere and nightly at certain times of the year when the flowers around my place in the trees are in flower around my place, there are 30 to 40 bats just feeding off my balcony in trees, basically. But what I say, yes, we did go we have been in lockdown. But what I and we were allowed to go out and exercise. So what I had noticed on my walks was that there is a lot of so we have another urban species. It’s not like the possums, but it’s a possum and so I think the possums were coming out a bit more and things were reclaiming some of the space or the urban wildlife was reclaiming some of the quiet spaces.

Richard: Yes, I’ve got some possums where I live, and I saw a bunch of them at people’s houses at night. I saw a lot more animals out, which was pretty cool.

Michelle: Yes. So I think that’s definitely happening all around the world, which is interesting.

Richard: It was raccoons eating garbage and possums and all kinds of stuff.

Michelle: Yes and they probably do that all the time, but maybe between 2:00 a.m. and 4:00 a.m. but all of a sudden they’ve got this great a window when there’s no one around, like in Florida, there might be a lot of fat raccoons and possums and things were very cool.

Richard: So what questions are you trying to answer right now? What are you honing in on with your research?

Michelle: So specifically, so when we’re just getting back into the lab, actually just this week, I want to go on something. Yeah, just this week, we’re starting to kick off the lab since March. So I talk about something a little bit different, kind of or just slightly different. But one of the things I try to achieve in my research is to like I can think up really interesting questions and do fun things but it needs to be translatable and it needs to be helping society or ecosystem or something in some way and so I have these citizen science project. Have you heard of citizen science?

Richard: Yes.

Michelle: So I’ve got these citizen science scientists project called Scoop a poop Citizens Tackle Antimicrobial Resistance in the wild and so what we do, we’ve got a little kit and we have we go out into schools and do outreach and talk about this issue of antimicrobial resistance and use wildlife as the example of the extent of human impacts and to wildlife and then we have kids run around and take will they take the kid home and I collect them from their backyard, send it back into us and then we tested in the lab and it’s a way of educating know nonscientists about the issue of antimicrobial resistance and what you can do to minimize the spread of resistant bacteria and but also getting them involved in science and collecting a sample and then helping us out by doing surveillance and understanding what’s happening in urban environments relative to the movement of these organisms and we can’t be in the field. So we’ve got this army of schoolchildren out there collecting, doing fieldwork for us and collecting samples. So that’s a pretty cool thing. So we’re just starting that back up again and doing all that via Zoom. So that’s a challenge. Yes.

Richard: What do you hope to see from the collection of the possum poop?

Michelle: So similarly, what I was talking about in the bats, but basically we’re looking to see what the prevalence of or occurrence of these resistant bacteria or genetic traits are in the possums, what types of traits they’re carrying in the bacteria, in the possums, not the possums themselves and then also doing a little bit more than the research extends a little bit more, again, to understand the role of possums in cities and spread of parasites and so we’ve got a project going with a collaborator at the University of Sydney, and she does possum personality and behavior and so she’s showing that. So this is Claire McArthur. She’s showing that possums have old personalities and will forage further and eat a different array of plant types and so we’re actually testing to see if their personality impacts the types of parasites that they carry and if they’re more likely to acquire parasites that might be spread onto humans. So that’s the other kind of thing we’re working on at the moment.

Richard: Is it hard to identify the possum poop?

Michelle: Oh, no, no. It’s very easy. It’s elongate. It’s about two centimeters long cylindrical. It’s one of the most common things you see around and when we go to the schools, that’s part of the training before we get the kids to go collect the sample for us and we actually guide them, so they can kind of key out different types of wildlife’s get samples. So you and you all walk outside here now and be under a tree and there will be 50 to 60 possum pellets. So it’s pretty easy to identify and pretty easy to collect.

Richard: Yes, I have dogs. I think they eat the possums or scare them away but other people that don’t show that they get in there and do stuff.

Michelle: Yes but they are a bit different. They’re both marsupials but they’re different lineages. So possums a little bit more closely related to the carnivorous marsupials like the Tasmanian devil, whereas the possums we have here are probably more closely related like koalas and they look very different.

Richard: OK, interesting. Well very good. I know you just got back in the lab and glad you’re back there and you’re doing this, this really cool research. So what’s the best way for people to keep tabs on your work and have their local to you? How do they find out more about it?

Michelle: Yep. So if anyone’s interested in citizen science, we have a website; scoopapoop.net or you can search on the university website Michelle Power, you will find me but we also have twitter. Hopefully, we will be appearing in newspapers and obviously, if there are researchers listening, they can look for my papers. 

Richard: Michelle, thanks for coming, I really appreciate it.

Michelle: And yes, I should also mention the Australian Society for Parasitology. That is another way of finding out about not just my work but also all the interesting work we do on the parasite.