UAlbany News Podcast

How Zebras Can Help Us Understand Anthrax Transmission, with Wendy Turner

Episode Summary

Wendy Turner is an assistant professor of biological sciences in the University at Albany's College of Arts and Sciences. She is researching how anthrax is transmitted among African Wildlife. Turner was awarded a $2.5 million grant from the National Science Foundation for this project.

Episode Notes

Wendy Turner is an assistant professor of biological sciences in the University at Albany's College of Arts and Sciences. She is researching how anthrax is transmitted among African Wildlife. Turner was awarded a $2.5 million grant from the National Science Foundation for this project.

The UAlbany News Podcast is hosted and produced by Sarah O'Carroll, a Communications Specialist at the University at Albany, State University of New York, with production assistance by Patrick Dodson and Scott Freedman.

Have a comment or question about one of our episodes? You can email us at mediarelations@albany.edu, and you can find us on Twitter @UAlbanyNews. This show is available on Apple Podcasts, Google Play, Radio Public, Spotify, iHeart Radio and TuneIn.

Episode Transcription

Sarah O'Carroll:
Welcome to the UAlbany News podcast, I'm your host Sarah O'Carroll. With me today is Wendy Turner, an assistant professor of biological sciences in the College of Arts and Sciences. She is researching how anthrax is transmitted among African wildlife.

Sarah O'Carroll:
Wendy, when you hear the word anthrax, what probably comes to mind for most people are the post-9/11 attacks where news organizations and politicians were mailed letters containing anthrax spores. But anthrax has existed naturally in the environment for a long time. Can you give us some historical context?

Wendy Turner:
Well, anthrax is a really ancient disease. It's true that, to most Americans, it sort of came into our consciousness in the 2000s, but it's been around for a really long time. People reflect, or have hypothesized, that some of the Biblical plagues were actually anthrax in Egypt. So in terms of recorded history, it's been around as long as we've known, and probably much longer. It's thought to have come across the Bering land bridge into the North America. So, very long time ago.

Sarah O'Carroll:
That's really interesting. Can you share what got you started on this project and what led you to study the disease in Africa's national parks?

Wendy Turner:
Well, I was first drawn to Africa, and then anthrax. I came there out of undergraduate as a field assistant working on a bovine TB project, and I got really into African savannas and African wildlife and disease ecology. I did a Masters' degree in South Africa working on that project. I got interested in, I wanted to keep working in southern Africa, but I wanted to expand beyond South Africa. I found a thesis that was written about anthrax in Namibia and it was just truly fascinating to me. Everything I read, every pattern that was presented just made it more interesting to me, and I wanted ... It's like, "Wow, those are such cool patterns. What is happening in this system? Why do you see the seasonality? Why is it so different from one species to the next?"

Wendy Turner:
I was totally hooked, and I ended up doing my PhD there and two post-docs, and I've been working there now. So it's been very ... It's the system that keeps on giving.

Sarah O'Carroll:
What about Namibia's patterns, as you said, were so interesting? I mean, what were some of your questions going in?

Wendy Turner:
It's not that Namibia is necessarily so unique, it was just that it was the first time I'd really sort of thought about anthrax as a wildlife disease. What's interesting about anthrax is it's always seasonal, but in the system I work in, Etosha National Park in Namibia, the seasonality differs from one species to the next. Some species, you'll only see cases in the wet season, some species, you only see cases in the dry season. What would be going on? I note, is it the susceptibility of the species, their contact with the pathogen? Why would you have this sort of separated seasonality by species?

Wendy Turner:
And then, some species get a lot of anthrax and some species don't, and what are the sort of factors that play, that create those kind of patterns? I was totally hooked.

Sarah O'Carroll:
Why did you choose the Etosha National Park and Kruger National Park? I know you just said that it wasn't Namibia specifically that made it so unique, but these other factors, but what made these parks perhaps better locations than others to study?

Wendy Turner:
I've been working in Etosha National Park since 2004, quite a long time. I've been studying anthrax there since about 2008, 2009, and I feel like I have a really understanding of the system. I've really dug into the patterns that are creating the sort of seasonality that we see, how animals are contacting the pathogen. I feel like I have enough of an understanding of that one system to be able to broaden my scope across scales to understand why anthrax is such a different disease in different areas. Because it is globally distributed, but it's quite different in different areas. 

Wendy Turner:
I mean, you're going to get different host species in different areas, because some places have deer and some places have buffalo and some places have zebras. So that's obviously going to be a thing. But you also have, the seasonality is different, the time between outbreaks is different. In some locations, like where I work in Namibia, we see cases every year. And then there's other places, like where in northern Siberia a couple of years ago, where they had the outbreak in reindeer. What they ended up having was, they hadn't seen anthrax there in decades or in ... I think it might have been 50 years or something.

Sarah O'Carroll:
Wow.

Wendy Turner:
And then suddenly, they have this explosive outbreak. So why do you see these sort of differences in terms of the number of cases, in terms of the timing between outbreaks? We really don't understand that. What's nice about the two systems that I'm working in is that you can then compare. They're two systems that are both African savannas, they have a lot of the same potential host species. They all have zebras and kudus and the things that we're working on. But in the one park, we see it's primarily zebras that are getting infected, a grazing species. And in the other park is primarily kudu, one that feeds on trees and shrubs.

Sarah O'Carroll:
And that's a type of antelope?

Wendy Turner:
It's a type of antelope, yes. So now we can say, "Okay, there's two systems. They've got different host species, yet, both hosts are in both parks. So what's happening there?" And then they differ in their seasonality, they differ in their outbreak intervals, they differ in the diversity of the pathogen. So what is sort of the underlying cause in two, from a long view, very similar systems, and yet in terms of disease dynamics, very different.

Sarah O'Carroll:
What is it about zebras and the species of antelope that make them especially vulnerable to anthrax transmission, or why did you focus in on these two animals?

Wendy Turner:
I focused in on these two species because they're the main host species in each park. By that I mean the number of cases observed are primarily the one species or the other. They're not necessarily so unique on their own, there's lots of different herbivores. In Etosha, there's two zebra species and there's a whole host, if you will, of bovines. There's a lot of potential host species, but for whatever reason, these are the two host species.

Sarah O'Carroll:
That's interesting. Now, why have scientists called anthrax a perfect pathogen?

Wendy Turner:
Well, I don't know perfect, but it's highly lethal, and it's an obligate killer pathogen. The only way it can transmit from one host to the next is by killing the host. When it comes to the evolution of parasites or pathogens, you generally don't want to kill your host because if you kill your host, you kill yourself. 

Sarah O'Carroll:
Right.

Wendy Turner:
So this is sort of a special class of pathogens where you actually need to be really lethal to actually escape the host and get into the environment to be able to be transmitted to the next infection. And anthrax is really, really fast, so within a herbivorous mammal, it can kill its host within a couple of days. It's a really fast infection, so it can easily sort of jump to the next phase.

Sarah O'Carroll:
I've also seen that phrase, perfect pathogen, to be a bit problematic because it doesn't really accurately exemplify what anthrax is and does. Is that correct?

Wendy Turner:
Yeah. And, you can argue that it's really good at what it's doing, what it needs to do. It needs to kill the host, it does it well. The flip side of that is that it has an Achilles heel, if you will, that you need a really large dose to actually kill the host. So if a host is exposed to a few spores, a few hundred or even a thousand spores, depending on the route, the host's immune system will be able to take care of the infection and it's going to not be lethal. Which, from the pathogen's perspective, that's a bad thing. That's a dead end.

Wendy Turner:
So you actually need really large infectious doses to kill the host, and depending on the routes of infection ... For wildlife, we're talking gastrointestinal anthrax, so they have to ingest the pathogen. And we don't have a lot of data on the lethal doses for that route, but the estimates are somewhere around 10 million to 100 million spores is what's expected to be lethal, which is a huge amount of spores, so this is not something you're going to sort of casually come across in the environment.

Sarah O'Carroll:
Now, take us into the lab for a moment. How does anthrax, as a naturally occurring pathogen, turn into a bioterrorism agent? I am neither interested in doing it myself nor asking for a friend.

Wendy Turner:
Well, I haven't done it myself, so ... I can tell you that anthrax, Bacillus anthracis, as a bioterrorism agent is the same pathogen as what we find in the environment in lots of different places in the world. The difference is, is that it's been purified so you don't have it complexed with soil particles, it's just the pathogen. You can select for small spores that are more likely to get aerosolized, more likely to lodge deep in someone's lungs, if you want to. But in terms of the pathogen, it hasn't been engineered to be more virulent in any way.

Sarah O'Carroll:
So it gives us that white, powdery substance as the absence of those other ... 

Wendy Turner:
Yeah, so it's just purified spores, and lots of them, if you can see a powder.

Sarah O'Carroll:
How could your research help public health officials and policy makers?

Wendy Turner:
Well, directly, I would say not very easily. The work that I'm doing is really to understand the epidemiology and the ecology of the natural disease. That's a step removed from public health, from policy. My argument is, the two systems that I work in, they don't manage the disease. Most places, well, it's actually reportable disease globally, so if you have cases in private settings or in most parks where you have it, you have to try to control the disease. You're going to be immediately deploying management measures such as incinerating carcasses, burying remains, that sort of thing, to try to stop the outbreak. 

Wendy Turner:
These two parks, they're large, and anthrax is considered a part of the natural ecosystem because it is thought to have evolved in Africa. They don't find that it's worth it, that the efforts required to actually try to control the disease are worse for the environment than just letting this natural player of the ecosystem exist there. Which, as a scientist interested in studying the disease, it's great, because you can actually study when an animal dies, what happens to that site, what happens to the carcass, what happens to the pathogen in the soil, where does that pathogen move to. Which is impossible to do in a place where you've controlled it, because you've destroyed that site.

Sarah O'Carroll:
Could you tell us a little about the grant you received for this research from the National Science Foundation? What does the grant fund?

Wendy Turner:
The grant is going to fund the research that we're going to do comparing the Etosha National Park and the Kruger National Park. We're trying to take a long view. We're going to be doing work on a lot of historical samples and historical data to understand what's really driving the system in either park. And then try to look when we compare the two parks, can we understand, is it totally different and unique in each system and you actually can't predict what's driving, or can you, when you have a really good understanding of the one park, can you translate that into what's going on in the other one. The goal, ultimately, is to be able to actually predict anthrax dynamics, anthrax outbreaks in different locations.

Wendy Turner:
At this point in time, you really have to have a good understanding of a local system to really feel like you have a sense of what's happening. I'm curious to know if we can understand more to be able to predict what's going to happen outside the locations we're studying.

Sarah O'Carroll:
Can you place your current work on a contextual timeline? Where are you right now, and what's next? Are you going to be returning to Africa?

Wendy Turner:
We are just getting started. We got the grant in early August, and we had a team of, I had two grad students, an undergrad, and a post-doc, and a Namibian student who's going to be doing a Masters' degree with us from the University of Namibia.

Sarah O'Carroll:
Oh, neat.

Wendy Turner:
We were all together in the park, just deploying our long term research projects. We put satellite collars on animals to be able to monitor in real time where they are. We put a grid of camera traps up to be able to monitor changes in host density in the landscape through time. We set up some long term experiments to try to understand how the pathogen is changing over time based on its genetic makeup. We set all those up because all of those are going to take several years to accumulate the data that we need for the project.

Wendy Turner:
And then we're going to be doing the same sort of matched experiments and projects in South Africa. One of my grad students will be going there next month, in just a couple weeks, to start setting up things in South Africa. It's taking a little bit longer there because I've been working in Namibia for years and years, and it's new collaborations and new relationships in South Africa, so it takes a little time to get all that set up. We're hoping to have everything set up in the first few months and then we just go.

Sarah O'Carroll:
Well, sounds like an exciting and strong start.

Wendy Turner:
I hope so.

Sarah O'Carroll:
Wendy, thank you so much for being here.

Wendy Turner:
Thank you very much.

Sarah O'Carroll:
Thank you for listening to the UAlbany News podcast. I'm your host, Sarah O'Carroll, and that was Wendy Turner, an assistant professor of biological sciences in UAlbany's College of Arts and Sciences.

Sarah O'Carroll:
You can let us know what you thought of the episode by e-mailing us at mediarelations@albany.edu and you can find us on Twitter, @UAlbanyNews.