In our final episode on vector-borne diseases, Anya and Ben talk with Dr. Kiersten Kugeler from the CDC about the role that fleas can play in spreading disease and which diseases they can carry.

To learn more, visit cdc.gov/fleas

Anya Morozov:

Hello everyone and welcome back to From the Front Row, brought to you by the University of Iowa College of Public Health. My name is Anya Morozov, joined by Ben Sindt. If this is your first time with us, welcome. We’re a student-run podcast that talks about major issues in public health and how they are relevant to anyone, both in and outside the field of public health.

Anya Morozov:

Today, we’re excited to have Dr. Kiersten Kugeler on the show. She works for the Centers for Disease Control and Prevention’s Division of Vector-borne Diseases. She’s been working with the CDC since 2007, and today she’s here as the third and final guest in our series on vector-borne diseases. We’ve talked about mosquitoes, we’ve talked about ticks, and today she’s here to talk with us about a lesser known vector, at least to me, fleas. Welcome to the show, Kiersten.

Kiersten Kugeler:

Thanks, Anya. Thanks for having me. Happy to be here.

Anya Morozov:

Yeah. Before we get to talking about fleas, we’d like to know a little more about you. How did you get started working at the CDC and what sorts of work have you done since you arrived?

Kiersten Kugeler:

Well, I first came to the CDC in the way that actually a lot of people do, that was in one of the several one- to two-year-long training fellowships that CDC offers. I’ve been working at CDC specializing in vector-borne diseases ever since. Some of the diseases that my team specifically works on include plague, Lyme disease and Tularemia. I’m an epidemiologist, which means that I study where diseases occur, who they affect most commonly and why, and ultimately work to improve prevention of those diseases.

Kiersten Kugeler:

As you all know, as students of public health, epidemiology is often considered the cornerstone of public health. Being an epidemiologist means you get to do a lot of different types of activities in public health. This ranges from surveillance, to research, to outreach and ultimately communication with a goal of improving prevention.

Ben Sindt:

To set some groundwork here, can you talk about like how come flea-borne diseases are and how are they transmitted and some of the basic details of these?

Kiersten Kugeler:

Sure. Well, the flea-borne disease that most people have heard of, and that’s because of its notorious past, is plague. Although people can be infected with a bacteria that causes plague in other ways, the most common way that people get plague is in fact from the bite of an infected flea. Here in the US, plague occurs in the Western states and it’s rare, but it is associated with high mortality, or risk of death. The two other primary flea-borne diseases that occur in the United States are flea-borne, or murine typhus and disease called cat scratch disease.

Kiersten Kugeler:

With this one, although fleas play an important role in the transmission of the bacteria to cats. The name itself implies how most people actually do get infected, and that is by cat scratches. I guess, overall these diseases do vary in their severity, but importantly, they’re all treatable with antibiotics. I did want to point out that we actually launched a flea specific website at CDC not too long ago. I definitely would encourage your listeners, who may want to learn more about fleas, to go there, but it’s pretty easy to remember cdc.gov/fleas.

Anya Morozov:

Yeah, we will add that link in the description to make it easier to access. You already mentioned flea-borne diseases are a bit rare here in the US, but what about globally?

Kiersten Kugeler:

Well, fleas themselves are common, as I’m sure a lot of listeners are well aware, especially if they have pets at home. There are in fact more than 300 different flea species in the United States alone, let alone what occurs globally. But you’re right, in general, we consider flea-borne diseases in humans to be less common in the United States than those that are transmitted by mosquitoes or ticks.

Kiersten Kugeler:

But honestly, there really isn’t good data about how common flea-borne diseases are globally. But invariably, as with many things, flea-borne infections are likely under recognized, particularly in resource limited areas. But we’ve got a really good idea about plague specifically, because of its past, because it does therefore elicit a lot of attention.

Kiersten Kugeler:

Overall, there’s several hundred to maybe a thousand or few thousand cases of plague that occur worldwide each year. Most of these are in sub-Saharan Africa. But here in the US, plague does occur each year in the Western states, that does surprise people. But as mentioned, it’s rare an average of eight or so cases a year, some more and some years have less.

Ben Sindt:

Yeah. Going on with the plague there, recently we learned that there’s a few different types of the plague. Could you go into what’s the difference between the types? Is it, could be like weather, or is it medicine, or what are all the things the play into these?

Kiersten Kugeler:

Yeah. Plague is a disease caused by the bacteria Yersinia pestis, and people often hear the term bubonic plague, but these different forms that you indicated, it’s still infection with the same bacteria, it just really comes down to how the bacteria enters the body. That contributes to what it looks like, what the person’s symptoms are and what a doctor may see when that person shows up.

Kiersten Kugeler:

The most common is bubonic plague. This is so named, because of the presence of a swollen lymph node, which is called a bubo. It’s a swollen and painful lymph node near the site of the infected flea bite. As mentioned, that’s the most common, because bites from infected fleas are the most common way that people get plague. The second form is called Septicemic plague, and that really is when the bacteria enters the human body, but there isn’t a bubo. There’s just a generalized illness. Then the last form is Pneumonic plague, characterized by a pneumonia, an infection in the lungs, and this is the most severe and most highly fatal form of plague. It’s also the only form that could be transmitted person to person.

Anya Morozov:

I always like to do a little bit of digging into the person on the show where I can, and based on the CDCs website, you’ve collaborated with epidemiologists in Uganda to respond to outbreaks of both Bubonic and Pneumonic plague. I was just curious to know, what have you learned from this work?

Kiersten Kugeler:

Yeah, we’ve, our team has worked in the plague endemic region of Uganda for about 15 years now. In fact, maybe a bit more, developing capacity for local health officials, to be able to do active surveillance for plague in both humans and animals, to build robust laboratory diagnostics that are able to be performed there locally, and then ultimately have the ability and the knowledge to intervene to stop any additional disease when it occurs.

Kiersten Kugeler:

This longstanding collaboration has been highly valuable for them, but also for us. I think, upon reflection, what strikes me most, having worked in Uganda for many years, is that the Western US, where plague occurs here is very different than rural Northwestern Uganda, but it’s the same disease. The risk factors for how humans get disease are very different between these two locations, approaches to prevention are therefore different, but it is the same disease.

Kiersten Kugeler:

That really does make things interesting from an epidemiologic and public health perspective. I think it just really underscores that we have to remain open-minded about what we know, and also what we don’t know about plague, why it occurs where it does, who it affects and why, and ultimately how to thoughtfully develop relevant capacity in any given area, because it may look different in different places of the world.

Ben Sindt:

Going off of that, you’re saying it could look different whether it’s in Uganda or whether it’s in the US here, but it’s the same disease. What are the steps to prevent the outbreak from getting worse and are there similar steps in both countries, or way different, or what are we looking at for prevention here?

Kiersten Kugeler:

Yeah, I mean, ultimately, as I mentioned, it’s the same disease, but there may be differences in how people get infected that really make it such that, having socially acceptable and culturally appropriate approaches to implementing prevention are vitally important. But what we would do here in the United States as a public health professional is essentially the same steps as what would be done there.

Kiersten Kugeler:

Ultimately first, you got to verify that it’s actually what you think it is, verify the diagnosis. That would be working with laboratory partners to make sure that the laboratory finding suggestive of plague is accurate. Then it’s about information gathering, gathering info about a patient’s potential exposures, the clinical status of the patient, details of the illness course itself. Ultimately as public health professionals, our goal is to mitigate or reduce any ongoing risk.

Kiersten Kugeler:

For plague, this means both environmental investigation and mitigation of the potential for infected fleas, but understanding if there’s also a potential for human to human transmission that needs to be mitigated. If there was a pneumonic form of the disease, evaluating if there were high risk contacts that need to be put on post exposure prophylaxis, to make sure that they don’t get plague from that initial plague infected patient. The final step and responsibility of a public health professional is also the same and that’s disseminating information, with the ultimate goal of keeping the community informed and really taking all ends to prevent further cases.

Anya Morozov:

Well, thank you. That was a really great summary of the work that happens during an outbreak. Really good for a hopefully future epidemiologist like me to hear. I didn’t want to have someone from the CDC come on the show without talking about a few kind of bigger picture questions to do with vector-borne disease. First big picture question, what would be your ideal wishlist for strengthening our responses to vector-borne diseases, both here in the United States and globally?

Kiersten Kugeler:

That’s a great question. I don’t think my wishlist would be specific to vector-borne diseases per se, but really just public health in general. That’s that ultimately, without an adequately trained public health workforce specimen transportation networks throughout the world, broad laboratory capacity and really data management systems in place, many parts of the world remain at risk for new diseases popping up and spreading before anyone really knows what’s happening.

Kiersten Kugeler:

It’s pretty cliche to say that diseases know no boundaries, but given everything the world has experienced in the last two years, I think that fact is more apparent than ever to more people. I hopefully that just puts it on the radar of more people. Ultimately we need to invest more as a society in public health infrastructure and training. The global health security agenda is a good recent example of recognition at the highest levels of government, not just in the US, but in many countries that our collective disease detection and response systems are really not what they should be.

Ben Sindt:

I know everyone’s a little bit more prone to looking for things that are up and coming now, because of the recent past few years, but is there any vector-borne disease that people are watching that could get worse right now in the world, or anything we’re keeping our eye out on?

Kiersten Kugeler:

Vector-borne diseases are common worldwide. They’re known diseases, in fact. Specifically they’re spread by diverse vectors. They’re caused by viruses, by bacteria, by parasites. There’s a lot there. In many ways, it’s hard to sort of single any of them out. That’s really just because in some ways they’re just so different. You’ve got very common mosquito-borne diseases that cause significant morbidity and mortality in many parts of the world, such as malaria, dengue, yellow fever. On the other hand, you’ve got far more rare vector borne diseases that are associated with high mortality and can really decimate communities quickly, plague being one of them. Ultimately reducing the risk of human exposure to insects and arthropods is critical to mitigating the role of vector-borne diseases known and as yet unknown.

Anya Morozov:

Yeah. Yeah. As nice as it would be to just be able to say, “This is the one disease that we have to watch out for.” I’ve definitely been learning, in my education at least, that the answer’s a little more complicated than that. As we wrap up here, we have one last question that we ask to all of our guests. What is one thing you thought you knew, but were later wrong about?

Kiersten Kugeler:

In retrospect, I think I’d wish I had known when I was in school that a career in epidemiology would draw from so many other public health disciplines, namely health communication and behavioral science. Those two creep into my, my professional world on a daily basis. To that end, I think in retrospect, I wish I had taken more classes in those disciplines when I was in school. But ultimately, that is the beauty of public health. There are experts in all related disciplines and it really is imperative that those people work together to achieve the common goal of preventing disease and improving health on a population level.

Anya Morozov:

Yeah. Yeah. I do definitely feel that has been true in my education. I wasn’t expecting to be doing so much as far as communication, especially, but I think the past two years have kind of highlighted the importance of being able to communicate well and learn from communities. I’ve definitely seen that in my education and even doing this podcast is an exercise in trying to be a better communicator. But yeah, that’s all the questions we have. Do you have any other last thoughts on fleas or vector-borne disease in general?

Kiersten Kugeler:

Well, I guess I would just throw a shout out to vector-borne diseases as a field of interest for students, just because there is so many different aspects to the study of such complex illnesses and nature and how they affect humans. Then I guess I would just also love to say I’m eager to see students coming into the public health workforce. Students right now and having been, a student through the COVID-19 pandemic, I’m sure that the students who are going to be graduating and entering the public health workforce in the next couple of years are going to bring entirely new insights and really transform the future of public health. I’m looking forward to it.

Anya Morozov:

Well, let’s hope. Let’s hope we can live up to that. Thank you so much for coming on the show today. It’s been great having you and I was excited when you responded to the email and really appreciate your time.

Kiersten Kugeler:

Absolutely. Thank you. Thank you for having me, and best of luck in the upcoming school year.

Anya Morozov:

That’s it for this week’s episode. Big thanks to Dr. Kirsten Kugeler for coming on with us today. This episode was hosted and written by Ben Sindt and myself and edited and produced by me, Anya Morozov. You can learn more about the University of Iowa College of Public Health on Facebook and our podcast is available on Spotify, Apple Podcast, and SoundCloud.

Anya Morozov:

If you enjoyed this episode and would like to help support the podcast, as always, you can share it with your colleagues, friends, or anyone interested in public health. Do you have a suggestion, question or comment for our team? You can reach us at cph-gradambassador@uiowa.edu. This episode was brought to you by the University of Iowa College of Public Health. Until next week, stay healthy, stay curious, and take care.