04/07/2017

Controlling The Lyme Disease Epidemic

16:54 minutes

Ixodes scapularis, a blacklegged tick known to spread Lyme disease in the northeastern regions of the United States. Photo by Macroscopic Solutions/flickr/CC BY-NC 2.0

If you live in some of the more bucolic areas of New England or the upper Midwest you probably know that the price of living so close to nature is ticks carrying Lyme disease. States like New York, Connecticut, Minnesota, Massachusetts are ground zero for a Lyme disease epidemic that has been in full swing for several decades now. And despite the fact that tick borne disease is so familiar to people who live in these areas, most of us don’t know as much as we think we do about the nature of Lyme disease.

[These scientists take a closer look at Lyme Disease under the microscope.]

Dr. Felicia Keesing, Associate Professor of Biology at Bard College explains why the complicated species interactions between ticks, mice, deer and humans make Lyme disease an especially challenging crisis to control. She is joined by Dr. John Aucott, Assistant Professor of Medicine and Director of the Lyme Disease Research Center at Johns Hopkins School of Medicine who discusses his work studying the way Lyme disease affects people.

Segment Guests

Felicia Keesing

Felicia Keesing is a professor of Biology at Bard College in Annandale-on-Hudson, New York.

John Aucott

John Aucott is an assistant professor of Medicine and the director of the Lyme Disease Research Center at the Johns Hopkins School of Medicine in Baltimore, Maryland.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow. If you live in the bucolic areas of New England or the Upper Midwest, you probably know that the price of living so close to nature is ticks, ticks that carry Lyme disease. And in fact, the name Lyme comes from Old Lyme, Connecticut. New York, Connecticut, Minnesota, Martha’s Vineyard, all of these places are ground zero for a Lyme disease epidemic that has been in full swing for several decades now.

And despite the fact that the disease is so familiar to those of us who live in these areas, there are many misconceptions about Lyme that can be pretty dangerous. For instance, Lyme disease is most commonly associated with deer– you know, that other nuisance that comes with living near the woods. But ticks actually pick up Lyme disease from infected mice. And did you know that the bullseye rash that comes with a tick bite sometimes doesn’t always appear? And that means it’s possible that you could have Lyme disease even if you never saw the bullseye, you didn’t have one, and you thought you were safe.

And the reason we don’t know as much as we think we do about Lyme disease is because it’s much more complicated than it appears. The bacteria have to learn to survive in their hosts. Species have to interact in a very specific way for the disease to be transmitted. And once it gets into the body, well, that’s maybe the biggest mystery of all, one that scientists are still working to solve.

And joining me to help clarify some of the mysteries of Lyme disease are my guests. John Aucott, Assistant Professor of Medicine and director of the Lyme Disease Research Center at Johns Hopkins University School of Medicine, welcome to Science Friday.

JOHN AUCOTT: Great to be here.

IRA FLATOW: Thank you. Felicia Keesing is Professor of Biology at Bard College. Dr. Keesing, welcome back to Science Friday.

FELICIA KEESING: Thank you. Thanks for having me on again.

IRA FLATOW: And if our listeners have any questions, the number, 844-724-8255 is our number.

Let’s talk about it. If you grew up around here in the last 30 years, you’ve heard about Lyme disease. We think we understand it. But not everyone has all the correct information, Dr. Keesing. For example, we associate Lyme disease with deer, but the bacteria doesn’t come from the deer. Right?

FELICIA KEESING: Right. The deer aren’t responsible for infecting the ticks. The important thing to know is that when the ticks are first hatching out of the eggs, they don’t have the bacterium at all. They have to pick it up by feeding on a host that’s infected with the Lyme bacterium. And different host species– it could be a mouse or squirrel or a chipmunk or a fox– each of those different species has a different probability of transmitting the Lyme bacterium to the feeding tick. And a host that’s most responsible, the host that’s best at doing that, is the white-footed mouse, by far. About 90% of ticks that feed on a white-footed mouse will pick up the infection. But deer don’t really don’t transmit the Lyme bacterium at all.

IRA FLATOW: Interesting. John Aucott, there’s something we thought we knew about Lyme disease in people that we’re finding out that is not quite right. And that is the classic bullseye around the tick bite. It doesn’t always happen. Right?

JOHN AUCOTT: That’s correct. I mean, actually the majority of the skin lesions are uniformly round and red. They don’t have that ring-within-a-ring Target department store look to them. People often mistake them for spider bites, because they’re just round or oval and red, sometimes, even bluish red.

IRA FLATOW: So how can you tell if you have been bitten? What’s the best way to know?

JOHN AUCOTT: The best way still is education of patients and physicians about the range of the appearances of the rash. So we always want to educate people to look for any round or oval skin lesion that’s bigger than two or three inches. So education is the first thing, for sure. And then also telling people that not everyone has a rash. So that summer flu-like illness with a fever and achiness and chills in June, July, in a Lyme endemic area could likely be Lyme disease.

IRA FLATOW: Because it’s really hard to see the tick, isn’t it?

JOHN AUCOTT: Well, that’s right. Only about 30% of people that get Lyme disease saw the tick that gave it to them, because the tick is about the size of a pinhead, the nymph stage that are feeding in the spring and summer. So most people, it’s actually easier to feel them than to see them.

IRA FLATOW: All right. Let me give out our number. 844-724-8255 if you’d like to talk about it. You can also tweet us at @SciFri. Do you see many patients who have lived a long time with undiagnosed Lyme disease because they never saw the bullseye?

JOHN AUCOTT: We do see some. And that’s because without antibiotic treatment, the bacteria has learned how to evade the immune system and can persist for months or even years if it’s not been treated with antibiotics. So we see people with late arthritis from Lyme disease. And those people have been infected sometimes for a year or longer before they come to diagnosis and treatment.

IRA FLATOW: Could the Lyme disease have been around a lot longer than we know it’s been here and have existed for centuries, and we just didn’t know it?

JOHN AUCOTT: Well, I think there is some evidence that ticks that have been recovered from storage have the bacteria in them. So it’s probably just one of those diseases that didn’t appear visibly until the last few decades. That’s right.

IRA FLATOW: All right, and could we have been misdiagnosing it all these years, and saying it was one thing and it was really Lyme disease that we didn’t know about?

JOHN AUCOTT: In North America at least, the disease really did emerge in the late ’70s and ’80s. And that had to do with environmental changes that favored the proliferation of infected ticks. So I think there was actually an environmental reason why the disease emerged in the late 1970s.

IRA FLATOW: And do we have a diagnostic test, a really positive test, that will tell you, if you get the test that you’ve had it or have it now?

JOHN AUCOTT: So the current diagnostic test is based on antibody production. Those antibodies take about two or three weeks to be formed. So the test does not work well in the first two weeks of infection when you want to try to make that earliest diagnosis. After two or three weeks of infection, then the antibodies form, and then the test starts to work better. But there is this gap in the first couple of weeks where the test does not perform well.

IRA FLATOW: Mm-hmm. And there is some controversy with this disease, the fact that Lyme doesn’t always look the same in people the way it does in the medical literature. Right?

JOHN AUCOTT: Yeah, I mean, textbooks, patients don’t always read the textbooks, so they don’t know what they’re supposed to look like. And so as a clinician, I certainly recognize that there’s a lot of variability beyond what the textbooks describe. That’s for sure.

IRA FLATOW: Dr. Keesing, how long does it take to infect a person? I think that’s also some mythology there that we don’t really know, most of the public doesn’t know.

FELICIA KEESING: So usually a tick, it takes a few days for the tick to feed on you before the Lyme bacterium mobilize from the tick and actually make their way into your body. So for Lyme disease, as long as you get the tick off within a couple of days, you’re usually OK.

IRA FLATOW: So you mean the tick can actually stay on your body that long?

FELICIA KEESING: Yeah, ticks feed for several days.

IRA FLATOW: Wow. Wow.

FELICIA KEESING: I mean, they’re sort of remarkable because each tick lives for about two years. So that’s their maximum lifespan. But during that entire two-year period, they only feed three times. So feeding for a couple of days seems reasonable if that’s one of your three meals in your two-year lifespan.

IRA FLATOW: So what are the other two meals?

FELICIA KEESING: Well, it’s the same thing. So as I said before, they hatch out uninfected with the bacterium, and they go through three life stages from that point. So they start out as a larva. They take a single blood meal as a larva. Then they molt into the nymphal stage, take their second meal as a nymph, molt into the adult stage, and then take their final meal. And that all plays out over a three-year period with each of the meals taking just a couple of days. The rest of the time, the ticks are living down in the soil, and we never see them.

IRA FLATOW: I talked with John about the discovery of the disease. Why was Lyme disease discovered or emerged only about 30 years ago?

FELICIA KEESING: Well, a lot of people think that– well, we know that it’s been around for a very long time. And one guesses that the symptoms are generalizable enough that it took people a while to figure out that this was something distinct from just general malaise and flu-like symptoms. But there’s also some pretty good evidence that we’ve done things to landscapes around the country, particularly in the Northeast and the Upper Midwest, that have led to increases in the amount of infection in ticks.

IRA FLATOW: Of course, you would think that this has generated a lot of phone calls. So we’re going to try to go to a few of them. Let’s go to Mary Jane in Oakland. Welcome to Science Friday.

MARY JANE: Thank you.

IRA FLATOW: Go ahead.

MARY JANE: Glad to be here.

IRA FLATOW: Thank you.

MARY JANE: So I have more of a comment than a question. I was bitten by a tick in California in 1989 or ’90. And I was not diagnosed until 2003. So saying that people usually get diagnosed within a year is absurd, at least in this part of the country. I think if you’re in Connecticut or New York, you’re better off. But out here, they tend to ascribe the progressing symptoms, which are different from person to person, in most cases to just being a little hypochondriacal or a little nutsy. And so getting someone, a doctor, who will listen to the ridiculous list of symptoms that people suffer is like finding gold in your backyard.

IRA FLATOW: That’s interesting.

MARY JANE: Yeah, and what I’m saying is really common.

IRA FLATOW: All right, let me get some comment. Let me get some comment. Yeah, I’ve heard it from other people. Dr. Aucott or Keesing, what have you got to say about that?

JOHN AUCOTT: Well, I’m very sympathetic to the caller because as this disease has moved geographically, it’s kind of a moving front. So it started up in Lyme, Connecticut, New England. But as it moves south and north, each new area each year is new to the disease. So the learning curve for physicians and patients both kind of restarts as it moves into new areas. So it’s no longer just along the coast of the East Coast. It’s moved westward across Pennsylvania and New York. So as it moves, we have to reeducate physicians and patients.

And I’m very sympathetic to the caller. There still is a lot of misdiagnosis of Lyme disease. It can be a tricky diagnosis when it doesn’t have it’s textbook manifestation.

IRA FLATOW: And what about the accepted treatment? What is the standard treatment for it now?

JOHN AUCOTT: So the standard treatment is antibiotics. This is a bacterial infection. And the standard treatment is with antibiotics. There are a subset of people that– actually, what we study at the Hopkins Lyme center– that after antibiotic treatments still have persistent symptoms. And those people are more challenging to understand and to treat because we don’t understand right now why this small subset of people that have post-treatment Lyme disease syndrome still have the symptoms even after the antibiotic treatment.

IRA FLATOW: All right, speaking about that, here’s a tweet from [INAUDIBLE], who asks, after antibiotic treatment for Lyme, is it important to follow up with another blood test?

JOHN AUCOTT: So unfortunately, the blood test doesn’t directly measure the bacterial infection, the borrelia burgdorferi bacteria. The currently available blood test that’s commonly used measures antibodies. And that test does not correlate with a treatment of cure. So unfortunately, we don’t really have a treatment of cure right now because we’re not able to re-measure the bacterial infection itself. We’re relying on these antibodies, which are made by your immune system. And they persist for long periods of time after the infection is gone.

IRA FLATOW: I’m Ira Flatow. This is Science Friday from PRI, Public Radio International.

Why don’t we have better tests for Lyme disease? Why?

JOHN AUCOTT: The bacteria borrelia burgdorferi is very difficult to study and to do research on. This is a bacteria that’s related to the syphilis bacteria. And that bacteria, we still haven’t learned how to grow in culture yet. So this isn’t a bacteria like staph or strep that you can easily work with in a laboratory and easily cultivate. So it’s a tough organism to do research on. And that’s really slowed the ability to come up with new diagnostic tests. We’re working on it. But it’s a difficult challenge.

IRA FLATOW: Let’s go to the phones, in Denver, to Max in Denver. Hi, Max.

MAX: Hey, how’s it going? Thanks for taking my call.

IRA FLATOW: Hi, go ahead.

MAX: So I’m a Bard College alumni myself. And definitely people in that part of the country, up in Upstate New York and the Upper Midwest, they’re well aware of the symptoms of Lyme disease and they know to be cautious. I was wondering if the experts here could comment if there was any coordinated effort for people that are vacationing, say, in the Upper Midwest or vacationing in New England, if there was any coordinated effort to keep them informed and up-to-date to look for the symptoms of Lyme disease and to check for ticks.

IRA FLATOW: And the kind of clothing that they should be wearing. Good question. Thanks for that question. Felicia or John, any follow-up?

FELICIA KEESING: I can say that in a lot of natural areas where you’d expect to have relatively high rates of encounter with ticks, people have petitioned to have communities put up signage that warns against ticks and tells people how to dress themselves properly and how to do a tick check. But those are certainly not everywhere they could be. So I think visitors are particularly vulnerable.

IRA FLATOW: Let’s go to the phones. David in University Park, Maryland, hi, David.

DAVID: Good afternoon. I have three short questions. First, is there a way to detect the prevalence by examining the host? That is, are the hosts asymptomatic, or do they show signs that can be detected? Second, what antibiotics are most effective? And is there any development of resistance to those antibiotics yet? And third, if this disease were better known, would there be better funding? Or is funding not a problem?

IRA FLATOW: OK, thanks. We’ll see how many we can get. What about the host, the mice?

FELICIA KEESING I could do that.

IRA FLATOW: Yes, go ahead.

FELICIA KEESING Yeah, so that’s interesting. We’re just finishing up a big research project asking that very question about the mice, which are the host most responsible for infecting the ticks here in the East. And they basically show no symptoms whatsoever. We’ve measured their behavior, their survival, the number of babies they have, what roles they play in the forest. And we see essentially no effect. So at least for mice, they do not appear to be a pathogen the way that they are for us. There are some other hosts that do respond to them, including some people’s pets, right, which is one of the reasons that people are so vigilant about ticks on their pets. But at least on their most important host out in the wild, the white-footed mouse, those appear to be asymptomatic.

IRA FLATOW: And the answer to the other question– if there were more people with it, would we have more research into it?

JOHN AUCOTT: You know, there are plenty of people with it. There’s 300,000 or more new cases every year. So this really ranks as the top– what we call a vector-borne illness, one translated by ticks or insects. It’s a hugely first place disease. So there’s a lot of illness. So we obviously need more funding into the research.

One of the areas that he brought up is antibiotic resistance. It’s hard to study because you can’t culture the organism. And if you can’t culture the organism, then you can’t do resist testing. So that’s an example of where we need funding for research.

IRA FLATOW: That’s all the time we have, a very interesting and timely topic. John Aucott, Assistant Professor of Medicine and Director of the Lyme Disease Research Center, Johns Hopkins University, and Felicia Keesing, Professor of Biology at Bard College, and she joins us via Skype– thank you both for taking time to be with us today.

FELICIA KEESING Thank you very much.

IRA FLATOW: You’re welcome. And if you’re curious about more, shall we say, unconventional approach to tackling Lyme, look out for the new Science Friday podcast coming out, called Undiscovered. We’re launching it on May 9th. And in one episode, our reporter Annie Minoff heads to Martha’s Vineyard to hear about a proposal to get rid of Lyme on the island by making a better mouse. That’s coming up this May, our new podcast, Undiscovered.

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