Tick Talk 2022

(electronic intro music) - Hello, this is Lab Medicine Rounds, a curated podcast for physicians, laboratory professionals and students. I'm your host, Justin Kreuter at The Bow Tie Bandit of Blood Transfusion Medicine Pathologist at Mayo Clinic. Today, we're rounding with Dr. Bobbi Pritt, Professor of Laboratory Medicine and Pathology and Division Chair for the Department of Clinical Microbiology at Mayo Clinic here in Rochester, Minnesota.

And we're gonna be talking about this year's tick season and what it means for individuals working in the hospital setting. So thanks for joining us today, Dr. Pritt. - Oh, it's my pleasure to be here. - Hey, so what does this season, tick season look like?

I've been hearing that it's predicted to be severe. What is that? - Yeah, well, that's what the predictions are right now. Of course, that could change, and it's hard to what the weather's gonna be. But yes, it looks like because of our milder winter and that's gonna allow the ticks to survive, more ticks to survive our cold Minnesota winters and other parts of the world, or parts of our country, that, yeah, there may be more ticks out and about this year.

And we're certainly seeing that in the laboratory. We've received a lot of tick submission so far. - I see.

So, I mean, you mentioned some of the weather kind of patterns changing. What are the different things that make it that kind of influence on the tick season? I guess not being, you know, working as a subspecialist in in microbiology, like you are, I'm not really attuned to, or I don't recall hearing about, you know, the tick season being severe or not. - Yeah, you know, it's complicated, it's multifactorial, and weather is indeed a pretty important part of it.

So if you have warmer, wetter winters, you're going have more ticks survive. And that means that they are come out and if you have an earlier spring, they're going be out earlier. They come out as soon as the snow melts. But of course, they need to feed and they feed on small animals, initially, small rodents, for example. So if you happen to have an abundance of rodents because perhaps there was an abundance of acorns, then you may have more food source for the ticks.

And then that may increase the number of ticks. And then last, but not least, you also have human behavior. If humans are out and about and going out into the woods because it's safer than, you know, being in close contact because of COVID, then that could also increase the risk of tickborne diseases. So it's really the ticks themselves, what they feed on, the so-called reservoir host, which includes small mammals, rodents, deer and humans, of course.

And then human behavior and what we're doing as far as expanding into populations where ticks may be. If we're out mowing our lawn, if we're creating new housing development in forested areas and we're infringing upon that region where ticks, and deer and rodents are found, there may be more contact. - Yeah, certainly. I know my family, we've been doing a lot of these, I've been enjoying our post-dinner walks during COVID.

But yeah, we have been getting out quite a bit more than maybe we have in previous kind of pre-COVID summers. - Yeah, it's been really interesting, Dr. Kreuter. So we follow all of the infectious disease, all the organisms in the laboratory that we test for. Some have taken a real hit. Influenza was down during COVID, probably because we were masking, and social distancing and that's a respiratory virus. Enterovirus is down. Bordetella pertussis is down. But tickborne infections is up.

And I think that's because it is something that people can do while they're socially distancing. And yet the ticks don't care about COVID, they're gonna bite you regardless. They don't socially distance (Dr. Kreuter laughs) - Much to our chagrin. - I know. - So you mentioned, you know, working in the laboratory, what you're starting to notice.

And I'm curious for, you know, what does that mean for, you know, all of us, you know, who work and also for our students who might be listening that are learning in our hospitals. What does the severe tick summer mean for all of us? - Well, I think it means that we're going to see more laboratory tests surrounding tickborne diseases.

So in my laboratory in clinical microbiology, that may mean seeing more ticks being submitted for identification, more tickborne pathogen tests for things like Lyme disease, anaplasmosis, babesiosis. But it's going to impact other areas of the laboratory as well. So for example, one of the hallmark findings in the laboratory for many tickborne infections is leukopenia, specifically lymphopenia, thrombocytopenia, and elevated liver function tests.

So those are some basic chemistries that people may see increased in orders for, to evaluate patients

that potentially have a tickborne infection. And then of course, some infections have non-infectious entities in their differential. So we may see more ordering for things that could be tickborne but could be something else. So it could impact across the laboratory in different areas. - Oh, have you been getting some invitations to kind of talk with some of our clinical colleagues about that differential diagnosis?

I imagine that's something to kind of revisit with the learners periodically over time. - Yeah, I try to do that every year. We always host some educational events for tickborne pathogens in general. And we do it for laboratorians, for our clinical colleagues and also for the general public. I usually give at least one talk every year

on how to protect yourself from tick bites because that's so important. - Oh, that's awesome. Hey, so you mentioned about the infections that are associated with ticks and about that differential diagnosis. And maybe I'm going off in the wrong direction here. Please let me know if to reel back in. But, you know, a lot of times with microbiology, I guess with bacteriology, I think about kind of superbugs and kind of is there any concern with something about severe tick season?

You know, are these infections going to be worse and more severe in the same kind of way? - So, great question. At this point, the tickborne pathogens, at least the bacteria that cause tickborne illness, seem to be susceptible to our standard drugs we use, which is mostly doxycyline, which is an antibacterial agent. Having said that, we always are monitoring to look for cases that don't respond to your typical therapies.

And I will also mention that there are things like viruses and parasites, which don't respond to antibacterials at all, and we don't have any effective treatments for. We're seeing more cases of viral diseases, like Powassan virus, Heartland virus, Bourbon virus. Babesiosis is a parasite that also doesn't respond to antibacterials. So to answer your first question, we are not seeing any superbugs, yet, hopefully never.

But we are seeing things more and more that we just don't really have good treatments for. And that would be right now the viruses. - Hmm, I gotcha. So, you know, going forward, I'm trying to get a a sense

of this kind of this cycle on what are some of those factors that make this, you know, a worse or more severe tick season. And, you know, is this gonna be kind of undulating, oscillating over time going forward? Or is this something where, you know, it's likely to get progressively worse? I guess what are experts in the community saying? - Yeah, it's complicated. I wish I had a crystal ball to predict. But we do well understand some certain patterns.

So first of all, warmer, milder and wetter winters means that more ticks survive. So with global warming and climate change, if we continue to see warmer winters, that's going to increase the risk for tickborne diseases. Earlier springs mean people are out and about. Longer summers and falls mean people are outside longer. So anything that's gonna change those patterns is going to influence tickborne diseases. And then also ticks are migrating.

They're expanding their ranges substantially, from the Northeast, the Upper Midwest, up into Canada, we have the Blacklegged tick. And those ranges continue to expand every year, putting more people at risk for things like Lyme disease, babesiosis and anaplasmosis. Now, there's a caveat, though, that as the warm weather gets very hot and dry, then the ticks will often go into hiding, 'cause they out very quickly. So hot weather in and of itself doesn't necessarily mean more ticks.

But when it's accompanied by high humidity and moisture, then that's perfect weather for tick survival. - I see.

You know, one of the things that our audience may not know, I guess I've seen photos of you doing research in the field. So, you know, a lot of times we think about medical researchers with Erlenmeyer flasks in a very sterile lab, but you do a lot of research in the field. I was curious if you have a favorite story about those experiences of leading some of these students and other colleagues into the field to do some of this tick based research.

'Cause I think this is just fascinating in an aspect of your practice that just most people aren't aware of. - Yeah, thanks Dr. Kreuter. It is a fun part of my job. So I'll give you a little background. I was able to do a Mayo Foundation Scholar Program right after my fellowship here. And I went to the London School of Hygiene and Tropical Medicine and took classes in entomology, parasitology. Got my master's degree in medical parasitology.

And learned how to go out into the field and sample for ticks and mosquitoes. And then you could take those ticks and mosquitoes, and go back to the lab and test them for various pathogens. So I was very fortunate once I came back to Mayo to be involved in discovery efforts for two new tickborne bacterial pathogens. And because they were brand new, we knew nothing about them, we didn't know what type of tick transmitted them.

So we wanted to ask those questions of, what is the tick that's the culprit here? Who's the vector? So for several years in a row, I went out into the field and collected ticks using those methods I learned back in London. And I would bring with me undergrad students, internal medicine residents, pathology residents, clinical microbiology fellows. And I even would team up with the CDC, and the Minnesota and Wisconsin Departments of Health and University of Wisconsin.

So we've had kinda tick parties where we all go out and drag for ticks. And then we, you know, have a big cookout and have fun afterwards. And then we sit down at the microscopes, identify the ticks, and then I would bring them back to my laboratory and test them like we would test a human sample. Not something we routinely do, but can do for research. So those have been great experiences and it's allowed us to really understand our two new emerging pathogens a bit more.

So haven't done it in a couple years since COVID, but I don't know, you know, there's always new pathogens out there. And if we discover something else, I'll be right out into the field again.

- Yeah, absolutely. Thanks for sharing that story with us. I think it nicely captures this, you know, interprofessional, you know, multi-specialty nature that is laboratory medicine and pathology. And we've been fortunate to have you as a guest on this podcast a few times, but I think this is the first time we've broken out the phrase tick party. - Tick party. Who wants a tick party?

(Dr. Kreuter laughs) - So thank you so much, Dr. Pritt for talking about this with us today, rounding with us about the ticks and helping us get our head around, why it's gonna be a severe tick summer, what this means for us in the laboratory. - Well, thanks Dr. Kreuter, I appreciate the opportunity to talk ticks anytime. - To all of our listeners, thank you for joining us today. We invite you to share your thoughts and suggestions via email.

Please direct any suggestions to mcleducation@mayo.edu and reference this podcast. If you've enjoyed Lab Medicine Rounds podcast, please subscribe. Until our next rounds together, we encourage you to continue to connect lab medicine and the clinical practice through insightful conversations.