9UNP1252_D_Susan_Paskewitz

- Welcome, everyone, to Wednesday Nite @ The Lab. I'm Tom Zinnen and I work here at the UW-Madison Biotechnology Center. I also work for UW Extent ion Co-operative Extension. And on behalf of those folks and other core organizers of Wednesday Nite @ The Lab, Wisconsin Public Television, Wisconsin Alumni Association, and UW Madison Science Alliance, thanks again for coming to Wednesday Nite @ The Lab. We do this every Wednesday night, fifty times a year. Tonight it's my pleasure to introduce to you Professor Susan Paskewitz in the Department of Entomology. She was born in Bangor, Maine, grew up in Michigan and Illinois, got her undergraduate degree at Southern Illinois University, and got her PhD at the University of Georgia, Athens. And then she post-doc'd at the Centers for Disease Control in Atlanta, Georgia. She came to Madison in 1991; So, she's been here twenty-four glorious summers. 

Tonight she gets to talk with us about new tricks for old ticks, tick-borne diseases in Wisconsin. Please join me in welcoming Susan Paskewitz toWednesday Nite @ The Lab. 
[applause]

- Thanks to everybody here for coming out. I'll just reiterate what Tom said: it's great to have such a nice crowd here on such a beautiful day outside. I, as Tom said, started at the University of Georgia and at the CDC, and my initial career was all in mosquito biology. So I did a lot of work on malaria to start with and then moved here, where ticks were kind of the big story. So I began to do a lot of work on tick ecology and biology at that point, and that's what I want to focus on for you tonight. And so I thought what I'd do is present a little bit of information on ticks in Wisconsin, and along with that, I want to talk about some of their fascinating biology. You might not like them very much, but hopefully you'll respect them a little more once I describe some of their life history traits. 

Then I want to talk a bit about some of the real changes we're seeing through some of our research on tick distribution. I will also talk, of course, about the main reason we care about ticks and that is the diseases they transmit. So I will start with Lyme Disease, but then I also want to make sure that you learn a little bit about some of the other things that not as many people, perhaps, in our state are aware of but that are definitely on the horizon and something that you need to know about. I also, if I have time, and sometimes I just run on and on, but if I have time I'd like to talk a little bit about some of our research now that's focused towards controlling ticks, trying to do something about them, and then looking at some of the ecology and why we have so much variation across the state in terms of the density and the risk, depending on what environment that you're in.

So, let's get started by talking about the tick biology and a little bit of their natural history. So, you might be surprised to learn that there are fifteen, maybe seventeen species in the upper Midwest. Here I think we have sixteen. And the ones that you encounter of those, actually, are these two that you're seeing here. The rest of them are usually very specific for particular animal hosts. So we have ticks that we only see on beaver, for example, and some ticks that we only see on birds. 

There are a few, like the wood tick and the deer tick that are a lot more catholic in their taste and they'll kind of feed on a wide variety of animals and birds. And I put the pictures up here so that you could just kind of contrast them. The wood tick-- and I wanted to say right here that a lot of people in Wisconsin call this species the "wood tick", so that's why I'm going to refer to it that way, as well-- but if you're an entomologist, actually, the correct way is to call it the American dog tick. So sometimes you'll hear that name as well. The other tick over there, of course, is the one that's associated with all the disease transmission. And this is the one that we Wisconsinites all call "deer tick", so that's what I'm going to call it tonight; however, if I'm at a national meeting of my Society of Entomologists, I have to remember that it's real common name is the Black-Legged tick.

So these are the ones that if you're out there in the woods walking around you're most likely to encounter, right? There is another tick now that I'd like to ask you to keep your eyes out for. And this is a tick that, if any of you have spent time in the southern, especially southeastern United States, you might have encountered. This is a tick called the Lone Star tick. 

Can you guess why it got its name? And the nice thing about this, this is a female, the nice thing about this tick is that if you were to see it you would recognize it, right? It's quite distinctive, these females are, in comparison with the wood ticks and with the deer ticks. And if you should find one I'd be very interested in hearing about that. And if you could actually try to keep it alive or freeze it until I can get my hands on it, then I could look at it to see if there are pathogens in that tick. But even a dried specimen, if you've got something dried, a neighbor has something dried, I can still, that's quite valuable to me just documenting where they are being found in the state.

So please keep them. And one of the reasons that we're really interested in Lone Star ticks, you can see here, this is a species, its specific name is Amblyomma americanum. This is the map of where you find this species in the U.S.. The dark green is the historical distribution; the light green is where we're beginning to see it move and where it's been documented. 

You see here Wisconsin has not yet been, nobody's published this tick in our state, but here are the records that I've accumulated since...what? 2006 on all the occurrences where primarily, it's actually members of the public, it's people like you who are seeing something that you don't know what it is, you recognize it as something unusual, and you get it over to us in the entomology department. We identify it and then make a note. And at that point we just try to remember to ask you if you have traveled. Because if you have been out of state, a lot of times that is where you might have picked it up and brought it back.

Now I got interested in this, actually, because I work a lot with people in the Wisconsin Department of Health, and they were starting to tell me that they were seeing a pathogen that is associated with this tick, but not with the wood tick and not with the deer tick. This is something that's called Ehrlichia chaffeensis, so it has a terrible name. But this species, they were beginning to see signs that some Wisconsin residents were getting infected. So that was one thing that got me interested. 

The next thing that got me interested is that I go out a lot into the state and I'm collecting ticks. And I was at a location that was very remote, so I was actually up here in the middle of nowhere, I swear, in Price County, you know, no people for, like, hundreds of miles, it felt like. In the middle of our study site I put down my sampling tool, which is a piece of white fabric that I drag across the vegetation, and I picked it up and there was a Lone Star tick attached to this piece of vegetation. I had not been traveling, so I didn't bring it with me.

The next thing that happened that year, this was in 2013, I was driving over to APT in Spring Green with my daughter and my husband. She got out of the car and I saw something weird and black on the back of her arm, and I said, "What is that? That looks like a tick." And, sure enough, it was another Lone Star tick, on my daughter! And I thought what are the chances that the one person in the state who would care about this 
[audience laughing]

 would actually encounter these ticks twice within the same summer? So I thought there was probably a lot more going on than we realized. And as you can see we're getting lots of reports now and actual sampling, especially in the southern part of the state. Dane is probably a hot spot because there are a lot of people here who know to contact the university when they see something unusual, and because we also do a lot of work here and we picked them up a number of times at our site.

So I said we care about them because they transmit disease. We also care about them for another reason and that is that the bite of the Lone Star tick is associated with some people developing an allergy to red meat. So I say the only thing that would be worse would be allergy to beer and cheese. 
[audience laughing]

 Documented, there's something in the saliva from this tick that is a kind of a sugar that looks like a sugar that's in red meat. So if you're bitten by this, your system becomes primed and then the next time you eat it, the meat, and are exposed to it, you can have everything from kind of hives to full-blown anaphylactic shock that sends you to the emergency room. 

So, we know of about a thousand cases now that seem to be associated with the bite this tick, none of them in Wisconsin yet that I'm aware of, but it's definitely a reason why we want to track this and we want to try to keep it out if we can.

So here is just a picture that shows you these different ticks that you're likely to encounter, so you can see them side by side. At the top here you see this is an adult female deer tick, here's the male, and then these are the immature stages. You notice that they're a little smaller, right? Then here's the Lone Star female, the one that's obvious to see. And then on the bottom, sometimes people send me this one. This is the female wood tick, or American dog tick. And I think when they read and hear that there's a white spot right in the middle, they see this white plate on the back of the tick and they think that's what we are talking about. But now you've seen what it really means is this little spot right here. Okay?

And I know you're not going to remember all of this, so I wanted to put in a plug for my website. If you find something and you'd like to see these pictures all over again and just be sure whatever it is you've encountered before you call me up and send it to me, go to this "Wisconsin Ticks" website. This is where I put all the information that I have about the ticks of Wisconsin, their distribution in the state, as well as all the different diseases now that we know that are transmitted by these ticks. And you can either get it with the actual http site, or the way I usually get to my own website is to Google "Wisconsin ticks." 
[chuckling]

 and it comes up right away. So I will talk a little bit about the biology now of ticks. And all of these hard ticks do basically the same thing, so I'm going to use the deer tick as the prime example here. In this picture what you see are these two immature stages at the top. And the first of those that hatches from the egg is this little guy. 

That's the larva. The larva has only six legs. That's meant to trick our students in entomology because, of course, insects have six legs but not arachnids, right? Well, the larva, if it's successful in getting a blood meal, it goes through a molting process and becomes this nymph. The nymph also has to get blood. If it's successful then it will molt to either an adult female or this adult male. You notice you can tell the male from the female by this plate. Again, the female has this very well-developed plate that's different from the back of her abdomen. And in the male that plate actually goes over his whole body. Usually the males do not seem to take much blood. 

We get them on deer, white-tailed deer, and on the deer once in a while it looks like they've taken a small sample, but they don't ever, you know, massively engorge. The females, though-- it's really amazing how much blood they require. So what you're seeing here is one on Day One before she's really begun to take up much blood. And over the course of the week, she's putting on 200 to 600 times her body weight in blood. She's taking that in. So if you just think about me, right? My 120 pounds: over one week I become, you know, how much is that even? Like, 10,000 pounds-- some horrible number, right? In one week! So think about the stresses on that creature in trying to deal with that. 

How would your skin even expand fast enough so that you could deal with all that volume? You have also a lot of blood in the system, and blood is associated with a lot of iron, and iron's a really toxic molecule, actually. So they have a lot of physiological challenges to try to deal with, taking up so this much material so quickly.

The female uses all that blood to make eggs. And each individual female is going to produce somewhere between 1000 and 3000 eggs, depending on the volume of blood that she was successful in taking. And then she dies. The female ticks do not then subsequently go and look for another host. So it's all over at that point.

Where do they get the blood? I said the adults, we find them very frequently on white-tailed deer. 

That does seem to be an important part of their life cycle, but it's for sure not the only thing that they'll feed on. Of course, they'll feed on us, right? They feed on our domestic animals, so cats, dogs. We have a large program in Wisconsin that we call the "Swat Program," where we have many partners who are veterinarians, they're animal rehabilitators, others who are working with wild animals. They send us the ticks that they're taking off the animals coming into those facilities, so much of these are dogs and cats, and we get a lot of deer ticks coming off of those animals. We also get them, of course, on things like wolves, and fox, and raccoons, so just a wide range of things that the adults are able to use for blood. I also showed you those immature stages, right? The larva and the nymph, and they require blood too. They don't feed on anything else. And so where they get it is actually from a wider array of animals. 

And that can include birds and a lot of small mammals. So here you see things like the white-footed mouse, chipmunks. But we also find them on deer. These immature stages can feed on deer. They can feed on skunks, opossums, just a whole array of things they're able to utilize. And the animal part of this equation, the wildlife part, is really important because that's where the ticks are picking up the disease organisms, right? This is where they're getting infected with something that they can then subsequently transmit to you.

So what we know from Wisconsin work is that these mice, either the white-footed mouse or the deer mouse here, we have two species that seem to be important, and chipmunks, especially in the southern part of the state, and then in the north you can add in this little guy at the bottom that not a lot of people are familiar with, called the red-backed vole. We don't see many of those down here in Dane County, but when we get to our northern sites we see lots of them. And so what has to happen here is that first stage, the larva, feeds on one of these animals, picks up pathogens, molts to the nymph, and the pathogen goes right through to the nymph. 

Now the nymph is going to be out there in the vegetation looking for a host, right? And then if it gets on you, unfortunately, it can transmit the pathogen at that point. The nymphs can also pick up pathogens during their feeding all the way through to the adults. So saying, if you get an adult on you can also become infected that way. Normally, in our study sites what we see is whatever the infection rate in the nymphs is, it's about double that in the adults. So I will show you some of this data in a minute. Before I get to that data, though, I do want to talk about a few myths related to ticks. These are questions that I have gotten more than once, actually, when I've gone out to talk to the public. And the first question that people ask me is, "Don't they leap on you from trees? Don't they climb up into trees and then leap on you?" 

So no, they do not do that. Ticks have this behavior, called questing, where they crawl up some kind of vegetation, or it can be a tree, and then they sit at the end of the grass or the tree with their front legs out. There's actually a couple of really sensitive sensory organs right here, and those on the tick's legs are picking up CO 2, breeze, so a little bit of movement might stimulate it, and a little bit of warmth. And when they get that signal, they know that a host is coming and then they have to actually contact the host in order to get on it. So, questing but no, like, leaping or flying out of trees to actually get on you. The other thing people sometimes seem to think is that the ticks will actively burrow completely down under your skin. And so there are some fleas that will do that -- I don't think we have any of those in the US, but there are some African species of fleas that will completely burrow under your skin-- but the ticks don't. What you see here is the ticks are actually inserting their mouth parts down into your skin, and then that's as far as it'll go. If you've ever wondered why it's so hard to get the ticks off once they're in, you can kind of see it here. If you look at these mouth parts, they're a little bit like fishing hooks, right? 

They're barbed and so that barb makes it much harder for you to just smoothly pull that, take out with a forceps once it's actually embedded. The other amazing thing that these ticks do is they secrete a little bit of a compound that turns into a hard cement right inside your skin. And that hard cement can also kind of makes it really hard for you to dislodge them and pull them back out.

So if you do have one on you, how should you get it off? How do you remove a tick? This is a source of endless amusement. 
[laughing]

 What are the ways people in Wisconsin get rid of ticks, you know? How do they pull them out? Well, some people say you should light a match and then take the hot match and touch it to the back of the tick. 

Many of you have probably heard this story, right? Specialists don't recommend this. The reason why we think this is a bad idea is because when you touch it with the hot match, it may regurgitate into you. You've shocked it, right? So the contents of its gut, actually, where the bacteria are that can make you sick, might actually be directed into your system. So you don't want to do that. The ideal way to get them off is to just take a nice sharp pair of tweezers, put tweezers down as close to where the tick's mouth parts are into your skin as possible. Slowly exert some backward pressure on it. You don't want to yank it out because you'll leave the mouth parts in your skin. So what you are really trying to do is get the tick to decide it wants to leave, fold up its tent, and pull itself out.

Alright. So now I want to talk a little bit about the history of deer ticks and Lyme disease in Wisconsin, what's going on here. The very first time anybody ever saw or reported a tick in Wisconsin was from Lincoln County and it was back in 1965. And this was forestry workers who, again, recognized that they were seeing a tick that they had not seen before. They sent it to my predecessor, Gene DeFoliart, a professor in the entomology department. And he was very interested after he got the identification, so he went back up and did more collections over, you know, four or five years. And so these are all the places that Gene found ticks through his various survey instruments. He also did look, like, from La Crosse down, I think, to Iowa County in the western part of the state and didn't find any deer ticks through those surveys. So at this point it kind of looked like these were northern and primarily northwestern for us. And then nobody was very interested, actually, in the deer tick once this was completed, these surveys were done. 

And so the work kind of just rested until in the 1970s, later on we recognized that Lyme Disease was becoming a problem, that it was a problem in the Northeast but also that we had a very important focus for this pathogen here in Wisconsin. So once Lyme became interesting, the state got interested in trying to understand a little bit more about the distribution of these ticks at that time. And we had this nice way to look for them because of their association with the host, with the white-tailed deer in the adult stage, coupled with the way Wisconsin handles the hunting season. And so the way we have done it and have done it for a long time is on the first day of gun deer season when the hunters take the deer to registration stations, we get students from lots of UWs to go to stations all over the state and they'll check, they try to check the deer fifty deer coming through, collecting all the ticks that are on each of those animals. So we get a snapshot that's nice and, you know, it's all across the state, all the same day, all the same methodologies. I like to show this figure-- this is from one of the recent deer surveys-- because this is Zip Johnson, who is in the Wisconsin Department of Health and her specialty is these vector-borne diseases. She wanted to help with one of these surveys. This the very first one she'd ever done, and I thought it was really funny that she wore her white coat. 
[laughing]

 She'd never crawled in the back of the truck with a dead deer before. 

So these are what some of those surveys look like. Really interesting. The very first one in 1981, what you're seeing here are pie charts where it's the percentage of deer that actually have at least one tick on them that's represented. So when it's black you can see, you know, more than half, then, would be infected with a deer tick.

I did the first one myself in 1994. And what I noticed with the data here was that we were seeing a pretty significant increase in the percentage of deer infested kind of up Highway 51, right up the center of the state. Not very much, though. Neither one of those surveys in the eastern third, eastern quarter of the state, you see almost nothing. There's one deer in Sturgeon Bay, one deer in a little town called "Poy Sippi" that had one tick on them, you know. So not much there yet. 

We did one of these again about five, six years ago and at that point, now, you see major changes in the eastern part of the state. So these ticks were definitely not done moving back in 1970s. And so over that-- what is it? 30, 40 years, you can really see a dramatic change. The range has expanded into eastern Wisconsin very significantly.

And along with the change in the tick range, here are some of the maps we have about what's happened with Lyme Disease over roughly that same period of time. If you look at 1990, most, the heaviest, incidence of cases is in the northwestern part of the state, and in particular, Barron and Burnett up around Spooner area, tends to be just reliably a very infested and high-incidence area. So it was kind of back in that day, I think, a lot of people would say that's where your risk is, right? You go to the northwest to your cabin and you really have to be careful, but you come back to Dane County, you're over in Milwaukee, there's no real risk there in your own yards. But now look where we are when you get down here to the summary of 2008 and 2010. 

That's very dramatic. We now see high incidence, lots of people getting sick in all of these places where we've seen the tick movement in the mid-90s, you know. With this last survey that we did that shows the ticks moving into the eastern part, it'll probably be within 10 years or so we may begin to see more increases there as well. Sure, yes? 

- How much of that do you think might be related to better diagnosis? Because I have a friend who had Lyme Disease back before 1990, and she went through all kinds of grief before they finally figured out what she had. 

- Very true. So there are different levels of publicity, and you can always see kind of spikes in the cases when there's been a lot of attention paid and that certainly was the case in the 1990s. I think at this point-- she's asking whether this change in pattern has to do with the change in diagnostics-- some of it probably does, some of it I'm sure has to do with stronger surveillance at the county level because this data actually comes from county public health, who are reporting to the state what the local doctors are telling them about the number of cases that they're identifying. So part of it is that, but part of it also is due to the spread of the ticks into new regions and also increases in the population and the infection rates in those regions.

So, I like to throw this in because it gives you a little bit of an idea about why we see this particular pattern. And you can see the tick distribution is very associated with the greener, the more forested parts of Wisconsin. And that's also where we also see a lot of the Lyme Disease. And that makes perfect sense to me because if I go out and try to sample for ticks for, deer ticks, I don't go to open meadows or grassy areas. That's not where I usually will pick up a lot of deer ticks. It is where I get a lot of wood ticks, however. Wood ticks are very abundant in those kind of open-meadow areas. But the deer ticks are very associated with wooded areas, wood lots -- of many different kinds of wood, they're perfectly happy, but they do like it better in those areas. So let me talk a little bit now about Lyme disease. And probably most of you know this is caused by a bacteria. 

Sometimes it's called a spirochete; the scientific name for that organism is Borrelia burgdorferi. Usually when I talk about tick infections, I don't say the ticks have Lyme Disease because they're not really sick. I say that they have the Borrelia infection or Borrelia burgdorferi. Lyme Disease manifests in a lot of different ways. If you're lucky, you'll get the bull's-eye rash, which is very diagnostic and occurs at the site of the tick bite. There are different estimates, though, in terms of how many people actually get the bull's-eye rash. CDC says maybe 25% of people don't, and other studies suggesting that maybe 40% of people don't get the rash. And the problem, which I can attest to, is these ticks are very small and their favorite place on my body, actually, turns out to be my head. That's where I always seem to find them. So I come in from the field and I'm doing this all the time, trying to make sure I don't have one there attaching to me. 

But suppose one does? Suppose I miss it? And I get the bull's-eye rash on my head, I'm not going to see it, right? Or if you get one in the middle of your back? You can imagine that would be a very easy thing to miss. So not everybody gets the bull's-eye rash, and it's not always in a place where you can easily see it.

So, other things that you might look for are a lot less diagnostic, so it's a little more problematic, you know? Fever, fatigue, muscle aches. I always tell my students, if you get anything that you think is summer flu, it just feels like you got the flu, you should go to your doctor right away and arrange to get some antibiotic. You should get treated as if it were Lyme Disease because summer flu is actually not very common, and, of course, the students who are working with me are highly likely to be in areas where there are lots of infected ticks. 

And you want to catch this early. If at all possible, you want to get treated early.

In Wisconsin, I showed you the distribution and the places where Lyme is the worst. I also wanted to show you a little bit about the patterns of people getting infected in our state. Tom said I first got here in '91, and that's right. And I started teaching a medical entomology class. And I would tell my students at that time we have about 400 to 500 cases of Lyme in Wisconsin and about 3 million of malaria, but okay. 
[chuckling]

 Five hundred cases of Lyme. But look at what happened: right around 2000 we had a change where it seemed like we had many more cases. 

And since then it just keeps, it's just gone up and up. So now, when I tell my students it's 2,800 to 3,000 cases, and I always give them the caveat here that that's the cases that are reported to the state and then are reported to the Centers for Disease Control. So is that the actual number of cases of Lyme that we have in Wisconsin every year? Absolutely not. I have talked to physicians who have said, "Eh, maybe we report one in 10." And that actually, that number I was surprised. The CDC came out a year or two ago and had done a study of this, and they concurred. They say it's probably about a ten-fold underestimate. So instead of 3000 cases, that means we get 30,000 cases that get treated, of Lyme, every year. So a fairly significant increase and a really significant problem.

We believe, the scientific community believes, on the basis of the patterns that we see in human infections that it's probably the tiny little nymphs that are doing most of the transmissions. You can get Lyme from the adults, but it's just easier to feel and find an adult. If you look at the size here of the nymphs, you know, they're so tiny. I mean I'm getting to the point now were I can't even see them. 
[chuckling]

 I can barely see the larvae on the drags, honestly. The nymphs are a little bit easier, but they're hard. They look like a small freckle on your arm. And more than once I've been sitting in my room after a day in the field, and I've done my careful tick check, looked over every piece of my body, taken my shower, and I am sitting there talking on the phone to my husband, and I notice one of my freckles is walking up my arm. 
[audience laughing]

 So it's real hard, you know, doing anything about the nymphs. You stay vigilant. But even so, it's going to be hard to catch all of them.

We do a lot of work with nymphs to try to get an idea of what areas have the highest risk if people encounter these insects, these arachnids. And so in doing that we're measuring the density of the ticks. How many are out there? What's the likelihood that you're going to encounter one say, every 10 meters or so? And then how many in that area are actually infected with Lyme Disease pathogen? And so these are lots of different study sites that we have: Maple Forest, we work in some managed red pine forests, we have urban sites and rural sites. And, this is a summary of a number of years' worth of data, but on average about 22% of the nymphs in Wisconsin are infected with Borrelia burgdorferi. 

And it's going to be about double that for adults, so about 40, 45. We have one location where one year we got 75% of the nymphs were infected with Lyme Disease spirochete. So very high. And that actually matters because there are some professional guidelines that inform physicians in terms of what you should do if a patient comes to you with a tick bite but not sick yet, they have no symptoms of disease. So should you wait for symptoms? Or should you give them a big dose of antibiotic prophylactically to try to head off any infection? And the rules that have been determined are: You got to make sure it's a deer tick. The tick needs to have been attached for 36 hours because before 36 hours the chances that they've actually managed to transfer the pathogen to you are much less. And importantly, more than 20% of the nymphs in an area need to be infected. So what I would say now is there's a ton of variation from year to year and place to place, but on average, 22% are infected. 

So a tick bite that meets these parameters should now be being treated.

Okay. So now I've scared you about Lyme Disease and how abundant it is in the state, and how likely ticks that get on you are to actually be infected with this pathogen. I do want to talk to you a little bit about some of the emerging infections that we're seeing associated with deer ticks. I mentioned one up there at the top called Borrelia mayonii. It's a species that has not been formally described yet. Was discovered in 2013 by the Mayo Clinic up around the Spooner area again. Is found in deer ticks and is transmitted by these deer ticks. Causes an infection that is detected by the same kinds of diagnostics that we use for Lyme Disease, so that's good. But it actually behaves a little different in people because with the Lyme in people -- I know someone who does diagnostics, runs the diagnostics labs at Mayo -- and she says it's really hard to ever get Borrelia burgdorferi in a blood sample. 

But this pathogen, Borrelia mayonii, apparently occurs quite commonly in blood samples, so it behaves a little bit differently. Treatment, though, is the same. Diagnostics also seem to be the same. Another pathogen that not many people are aware of is this anaplasma, human anaplasmosis. And I'll talk a little bit more about that one. There's a brand-new kind of Ehrlichia, another species called Ehrlichia muris, which was discovered in 2009 up in the Spooner area again. And we have a virus as well, Powassan virus, and deer tick virus probably very closely related things that occur here and are all transmitted by the same tick. And then finally at the bottom you see this thing, this parasite Babesia microti, which is actually a relative of the malaria parasite. So all of these things occur in our ticks. My lab actually does a lot of diagnostics on ticks for these. 

The one that I want to spend some time talking about is actually the anaplasma because that one-- you see here, anaplasmosis-- there are about 500 cases of that pathogen now every year in Wisconsin.

The other two here that I mentioned, Powassan virus, Babesiosis, those are still very rare and unlikely that you're going to encounter those.

So here's a kind of trajectory for the anaplasmosis. This is one was actually first identified by a doctor who worked at the Duluth clinic in the middle 1990s. And you see that again we're seeing more and more of this. It has me a little bit worried because remember what I told you about when I first got here for Lyme Disease, where we thought there were about 400 cases in the human population every year? We're about at that same point right now with anaplasmosis. And I actually don't know whether we will expect to see it do the same thing and causing the same large number of problems that we see with Lyme now. One of the things about this particular pathogen and the

relative Ehrlichia -- I've grouped them together because the way we diagnose them is usually very similar and they are kind of hard to tell apart by diagnostics -- the clinical picture, very similar, right? 

You got the headache, the fever, the fatigue. That's not really very helpful, is it, in identifying what specific thing is making you sick. Don't get a bull's-eye rash with this, though. Some people do seem to get a little bit of a rash that looks differently, behaves differently. So not a whole lot from the symptomatic perspective that would allow you to know that you have it. But you should know that we are actually a hot spot in the whole country. So, you know, for Lyme it's us and the Northeast, and there are a lot more Lyme cases in the Northeast. For this one actually Wisconsin and Minnesota are the hot spots. We have 50% of the cases in the whole United States. And again where do you find this? 

Well, it's in the same kinds of places where you'd expect. The same places where Lyme is very abundant. In terms of what's going on right now with the ticks, I just put up a figure from a couple of our sites in the south: Kettle Moraine and one near Black River Falls, where we've got a long-term study going on. And you can see in those nymphal ticks it ranges from none all the way up to 15% percent in 2009. But more normally, it tends to be in that 4 to 10% of the nymphs are infected. And yes, some of those nymphs will be infected with both this pathogen and with the Lyme Disease spirochete. And we even have, I think, one or two records where we have a tick that's infected with Babesia, Lyme Disease, and anaplasma. So if you were bitten by that one, you know, you'd have the trifecta of disease agents. For most of these things the good part is, you know, if the doctor treats you for Lyme Disease and you really have anaplasma the antibiotic will still work. Right? 

So the antibiotics in general are effective for the three kinds of things. If you get Powassan virus, well, viruses we don't have as good a group of drugs that can deal with that, so supportive care is really all that's available. And for none of these things do we have a vaccine yet that you could take. Okay, so for the last part of my talk I want to discuss a little

bit of what we are doing to test some of the methods that we might use to reduce the prevalence of these ticks and the pathogens that carry. So for the most part the message that public health has for you is that you need to be careful to protect yourself, right? It's personal protection. Much like we tell you with mosquitoes and West Nile virus, if you're going to be outside you got to put on your repellent and you need to wear the DEET. For ticks we recommend that you actually wear long pants, that you tuck your pants into your socks. When I go to the woods with my students, I make them go to Farm & Fleet and buy rubber boots that come up to the knee. 

And if they don't buy the rubber boots, they have to take duct tape and very tightly make a boot, in essence, wrap and affix their socks to their pants. That's because, of course, these ticks are down close to the ground, very low, and they're going to get on your boot or shoe. They don't seem to like the boots, which is really interesting I don't think they even get on the boot. They will get on your tennis shoe and then kind of walk their way up. So the next thing that I do with my students is I have them actually treat their clothes. And we treat the clothing with an insecticide called permethrin. You spray it on and then you let the clothes dry, and then they're safe to wear. The military uses the same thing for the same reason for the soldiers. But then when the tick tries to crawl up, it gets a dose of the insecticide and it dies before it is actually able to transmit the pathogen. So that actually has worked really well. 

With 30 students over the last 10 years or so, we've only had one case of tick-borne disease. We had one student who got Lyme, but actually we think she got it after the field season because she'd been up to Devils Lake and she didn't wear her boots. Anyway, you know, that's the kind of stuff that public health has to offer you, which most of you aren't going to do. Right? How many people are going to tape up their pants and wear their, you know --- that's so geeky, you're not doing that! So we are thinking about, okay, what else do we have to offer? What are some other things that we can do? And in particular we're interested in thinking about the household environment. So maybe, you know, an acre, half-acre or less around your home so at least in that area maybe there could be some prevention. And we're very interested in doing this in such a way that we reduce environmental impacts and so we are actually targeting the host. 

You remember that the white-footed mice are a very important source of blood for the immature ticks. And these mice are also an important source of the pathogens back to the ticks, so our target is the mice. The thing that we are testing is whether we can give the mice a nest material with this permethrin treatment so that when they go back, make their nests out of the cotton balls, they get a nice coat of permethrin all over their fur, doesn't hurt the mouse, but any tick that gets on the mouse then dies, again, before it can pick up or transmit the pathogen.

So this is actually a commercially available product. You see it here; it's called Damminix, or Tick Tubes. They're pretty expensive, and they've not ever been tested in our situation with our small mammals. It costs about, I think it was $75 to treat an acre, I think it was. So we wanted to see if we could try to make a home-made version that was a lot cheaper and test it in our own backyard. So this is one of my graduate students with a whole bunch of cotton balls. He's laying them out, and then he gets on his proper protective gear, takes the pesticides, sprays all the cotton balls, let's them dry. 

And then we take them back to the lab and we stuff tubes with them. For our study we decided to use PVC pipe because it's a long-term study and we don't have to keep buying, like, toilet tubes and stuffing those. So, we put the cotton balls in tubes, the students go out and place them in people's yards and at our study sites, and then what we hope is what you see over here: the mice make a nest and get that treatment.

So, the other thing we're thinking about here, of course, is that this will work for mice, but if chipmunks are a really important part of the cycle and they're feeding a lot of immature ticks, eh, it might not be enough. Right? It may not be enough. So is there something else we can do kind of in combination with the cotton balls that might give us more bang for the buck? So actually what the students are doing is to remove some invasive species, and in this particular case it's buckthorn. Some of our other work was showing that where buckthorn was really heavy, we had the heaviest densities of the deer ticks in these study sites. So it's kind of a win-win, right? 

Buckthorn is bad, get rid of the buckthorn, change the environment, now it's a little drier and the ticks don't do so well. So we combined the two things: we have some sites where we just remove buckthorn; some where we just put out cotton balls; and some where we put the two treatments together; and then some we don't treat at all. And we started this project last year with the treatments going in the spring. And what we found over the summer as we're trapping mice and other small mammals in these study sites is, sure enough, there are fewer ticks, quite a lot fewer ticks, attached to Peromyscus, to the white-footed mouse in the these environments. Alright. So that's really good. What we would hope then is in the second year as a result of that, we'd have a lot fewer nymphs that are actually in the environment that have picked up the pathogen last year and would then be ready to transmit to you. So we're looking for that right now actually. We're in the middle of our second season. It does-- I'll just give you a little hint-- it looks like it works, like, indeed, we are getting reduction in the numbers of nymphs in these study plots.

So in an ideal world, I would layer on another kind of control that would target the other major host. The other major host here is the white-tailed deer. And in some other parts of the country they actually have this 4 Poster System that does exactly the same thing. With the 4 Poster System the deer get baited in with corn and as they go in to eat the corn to get a dose of acaricide, something that kills ticks, as their head goes through these little baffles, basically. And then any tick that gets on that animal, again, is going to get the insecticide and will die before it can produce the egg. Can you think of why we might not be able to do this in Wisconsin?

Can't bait deer. Why can't we bait deer?

Chronic wasting disease, right? C-W-D. 

So, you know, I think if we're going to try to target deer in some way we're going to have to be more clever about it. Perhaps it would involve at some point some kind of a vaccine. But, you know, something that pulls them all into one area may be problematic.

So how much more time do I have, Tom?

- Another five minutes. 

- Another five minutes, okay. So I'm going to just show you one more piece of work we have done with... this is my field team here. A lot of these guys are absolutely essential to getting this done. Many of those are graduate students and undergraduates who work with me. 

And this last project I want to describe is trying to understand why there's so much variability in risk from forest to forest or even from a small patch within a forest to another small patch within the same forest.

So this is the study that was actually funded by the CDC and NSF. What we did here was to select a lot of different forests across the northern part of the state. Those are all maple forests, and then we're contrasting them with some managed red pine forests in the more central and southern part of the state. You'll notice that we tried to put them in areas where we have a lot of Lyme transmission based on human cases and areas where we don't have so much transmission. And so the very first big surprise out of this work was just in contrasting how many ticks there are, the density of these ticks, within these different forest types, or the same type but across this kind of gradient. I was shocked, actually, I think my whole community was shocked to see that these managed red pine plantations actually had higher levels than the maples did. I didn't expect that. The understory, the vegetation, is very different in those kinds of environments. And kind of oak maple forests are the classic place where we'd expect to see a lot of these deer ticks. 

But in our study, the Black River Falls and South Kettle, those were definitely the highest. I also wanted to point out that in 2013 was the worst year we have ever seen for deer ticks in this state. We've got longitudinal data from a number of different places now where we can compare from year to year, and it was absolutely incredible. There's one site I didn't even put on here because it was 720 on the axis. You know, basically you are hitting one nymph every meter. So lots of ticks that year.

We also have done a lot of work kind of within these maple forests so that is kind of a cross for us. We've done a lot of work within the forest to look at kind of the more micro-level of what's governing where we find the ticks. So each of these are sort of 500- acre tracts. Within each of the 500-acre tracts we have 16 different locations where we go and sample for the ticks. 

And we have this kind of result, actually, for the years 2012, '13, and '14, where you can see that there is a huge amount of variation in how dense the nymphs are within a site. It's not the same from year to year at all. Half as many in some years. But interestingly, the sites rank the same, so in every single year whichever site is the worst, and it turns out to be the American Legion Northern Highlands, that site's always the worst. The Flambeau, the million-acre swamp up there, that's almost always our second-worst site. We have a site in Chequamegon near Crivitz. And then another site that's actually pretty close to our Flambeau site and it's very low. It's always the lowest. And this is consistent from year to year. So there are definitely things at those sites that are driving the density of the ticks. 

And those, whatever those things are, we'd really like to understand. So it could be the mice. It could be the small mammals, right? It could be that there is a lot of difference in the mouse population. Places with a lot of mice would feed a lot of ticks and you'd expect there to be a much higher density. So my students and I have a lot of fun with mice. 
[chuckling]

 We track them, live-trap them. We measure them, we weigh them, figure out their age. We put little tags in their ears so if we recapture them, e know it, and then we can get estimates of how many are actually in an area. 

And we take the ticks off of them as well as a little biopsy so we can tell if they're infected with any of these pathogens. So lots of fun with mice.

The other thing we do with all these sites is we have camera traps out so we can get an estimate of deer activity. Because that's the other major part of this cycle. And so for our five maple hardwoods where we have these consistent differences, they ranked the same every year, the worst one's always the worst, the one with the least ticks is always the same, we don't see any relationship with deer numbers. That's not a driver. And we don't see any relationship with white-footed mice numbers either or deer mice. And that's a surprise, actually, because that's supposed to be really important mechanism for getting high-tick population. If you look here you see that actually the site with the fewest mice, that's the site where we see the most of the ticks. So we have lots of puzzles. 

Some of my graduate students are right now working

on those puzzles trying to work out if it's not the mice, it's not the deer, what is it about those sites that's so important? So hopefully I will come back maybe next year or the year after that I'll be able to expand on this story with you. So I want to thank you very much again for coming out today and I appreciate your attention. 
[applause]