Veterinary Vertex

Echinococcus Tapeworms in Dogs and Zoonotic Risks

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What if your dog could be harboring a parasite without showing any signs of illness- and could get infected in your backyard? Tune in as we host Dr. Michelle Evason on Veterinary Vertex, where she sheds light on the emerging health threat of Echinococcus tapeworms in dogs and humans, particularly Echinococcus multilocularis. Michelle reveals the surprising fecal PCR detection of this parasite in new regions of the United States, where it hasn't been reported before, along with detection in Canada. We dissect the complex diagnostic hurdles in dogs, such as mistaking alveolar echinococcosis for liver tumors, and explore the limited treatment options available for this invasive disease. Our discussion underscores the vital need for regular fecal testing in dogs to safeguard both canine and human health within the One Health framework.

As we delve deeper into the topic, we emphasize the critical role veterinarians play in educating clients about zoonotic risks, inspired by key insights from a JAVMA article. As Echinococcus multilocularis spreads beyond its traditional borders, it's crucial for veterinarians to be well-prepared to communicate these risks effectively to pet-owners. We uncover startling findings, such as cases in dogs with no travel history to known endemic regions, and address the confusion surrounding public health reporting of this parasite and limited awareness of this potentially deadly parasite. By examining the significant role of wildlife in transmission, we stress the importance of equipping veterinarians with the right tools and knowledge to tackle these evolving health challenges head-on. Join us as we empower the veterinary community to handle these pressing issues with confidence and clarity.

JAVMA article: https://doi.org/10.2460/javma.24.07.0471

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Sarah Wright:

You're listening to Veterinary Vertex, a podcast of the AVMA Journals. In this episode, we chat about emerging Echinococcus tapeworms in dogs with our guest, Michelle Evason.

Lisa Fortier:

Welcome to Veterinary Vertex. I'm Editor-in-Chief Lisa Fortier, and I'm joined by Associate Editor Sarah Wright. Today, we have Michelle joining us. Michelle, thanks so much for being here today and re-educating us on all the things we never learned or forgot about in parasitology.

Michelle Evason:

It's my pleasure, Lisa, and again I feel like I didn't learn a lot of these too, and so the past few years have been very much an infectious disease discovery.

Sarah Wright:

Yeah, I agree with Lisa. I remember learning it all for that second year examination and then I think it slowly kind of began to leave my mind. So, I'm really happy to have you here today. Your JAVMA article discusses emerging Echinococcus tapeworms in dogs. Please share with our listeners the background on this article.

Michelle Evason:

Thank you, and it's one of those things as we started off confessing all of our feeling a bit maybe I'll use the term imposter syndrome in and around GI parasites and I felt that way too. One of the things that we started noticing right off the hop as we were running

Michelle Evason:

And one of the things that we noticed right off the hop almost is early on after the launch of this particular fecal PCR test. He screened GI parasite PCR through Antec Diagnostics is we got an Echinococcus multilocularis test result detected in a dog from British Columbia, Canada, and that article actually appeared in one of your publications as well. We also realized when we got that test result that there was fairly limited or lack of awareness in and around Echinococcus multilocularis and its potential impact not just on dogs but also on humans. And then I'm going to bring in wildlife as well, because very much a one health aspect to this particular parasite and we wanted to work as quick as we could to raise awareness and inform, because we also recognize that the human medical profession has fairly limited or low awareness around this parasite as well.

Sarah Wright:

Yeah, thank you for bringing up that One Health perspective. I think that's something that's really unique, too, about this article.

Michelle Evason:

I couldn't agree more. And it was one where our Antec Consultation Service team. They speak to over 800 veterinarians a day and when we started getting these test detects come back again, we recognized pretty fast that veterinarians felt very uncomfortable. Not just about the test result as it pertained to the pet, the dog, but also in how to communicate risk to the human client right and so a fair amount of if I may use the word counseling in and around that. And so again really wanted to raise awareness because when we think of Echinococcus multilocularis, or when we think of it at all, most of us think of it as a parasite. That's sort of in bush, Alaska, or like a sled dog thing or, you know, a coyote or a wolf or a fox thing, or in like very limited parts of Canada when it comes up. But it's not, and that's one of the reasons we're really excited to have this case series. But just to kind of back up a little bit, because again this was pretty new for me. Domestic dogs and wild dogs, so coyotes, fox and wolves, the ones that I just mentioned, they're actually what we call definitive hosts for Echinococcus, Echinococcus multilocularis, as well as Echinococcus granulosis sensu latu, which I'm not going to get into too much today because we'll focus on Echinococcus multilocularis Clinical disease. The reason why this is important for dogs as well as humans is clinical disease can develop after infection with Echinococcus multilocularis, granulosis too, but again, we'll stick with multilocularis. The disease that can occur that's the most frightening in part because it takes a long time to diagnose in humans and sometimes in dogs and it can often be misdiagnosed is alveolar echinococcosis, and what that is is these very large cysts that really I think a lot of dogs do end up getting misdiagnosed, because when you pop that ultrasound probe on a dog it looks like there's a big liver tumor present, and so that's what can happen in dogs. But humans can also be infected with this particular parasite and it can take a long time for signs to develop. The other thing that's kind of awful about it, and another reason to really have it on your radar, is because it's very difficult to treat in dogs as well as in people, and it can be very invasive when treatment is needed in terms of surgery to remove that cyst and their limited drug availability and even the drugs that we have don't work all that well to prevent it. Usually, they can just kind of prevent it from developing further. So again, big reasons from a clinical standpoint, in humans as well as in dogs, to have this one on your radar.

Michelle Evason:

Dogs can also be what we call because they're the definitive host. They can get enteric so it can be excreted in their feces. And we can detect that when we're doing fecal screening as veterinarians, you know, by following along to the guidelines by the Companion Animal Parasite Council and in Canada, the Canadian Parasite Expert Panel. So that recommends fecal testing in adult dogs at least twice a year and then in puppies several times a year or on a risk basis, and so we can pick it up that way and detect it through fecal PCR in the feces. One of the things that I know you're going to ask me this and I'm probably going to just jump out ahead of it is this is kind of where there's some differences in the fecal test options that we use as veterinarians and they're not all created equal, and I would never tell a veterinarian what fecal test to use, because that's a decision for them, their practice, that particular client. I will say that when it comes to this particular parasite, fecal flotation is not very sensitive for picking up ania in general. So, you know, we were kind of chatting about how we refer to these parasites right, and the way I was kind of taught is oh, I just call them whipworms or I just call them hookworms or I just call them tapeworms. And within the broader tapeworm category there's a couple more specific parasites Taenia being one which we think about is fairly common in small animal, and then also Echinococcus, and so fecal float not great at finding Taenia in general. And then, unfortunately, if and when fecal float does find Taenia, it actually can't differentiate between Taenia type looking parasites and Echinococcus multilocularis. And obviously there's some pretty big differences, as I've gone through in terms of the human health as well as the dog health impacts, with Echinococcus as opposed to Tainia.

Lisa Fortier:

Michelle, what do you say to the skeptics that say, well, I'm not going to do all that fecal exam stuff, especially in puppies, just deworm them, because they're going to get worms anyway, so just deworm them.

Michelle Evason:

Yeah, for sure, and, and you know we get that a lot and honestly, Lisa, I would have been one of those people, right, like I used to be one of those people, and still until I, A. started informing myself a little bit more about parasitology and then B. also informed myself a little bit more about some of the pros and the cons and the limitations, as well as the benefits, of the different tests, I think that when we're talking about Echinococcus multilocularis, that's one of the best arguments that I have.

Michelle Evason:

If I you know, I feel a little funny using the word argument because it's not an argument because I do believe very strongly that, as veterinarians, we have to be accountable for One Health as well, and so when we have these potentially zoonotic parasites that we know can occur in our patient population dogs as well as cats, those are the sort of the species that I usually contain myself to. I do have horses, but I I usually defer to the experts on them, but I I will say, you know, we owe it to the two-legged as well as the four-legged to present this information that could be a danger to them in their household, especially if we know that they can take steps to mitigate this risk and Echinus caucasus multilocularis, and being able to detect that through fecal screening, as advised by these major guidelines, expert and evidence-based, is a pretty fast way to do that and I think our responsibility, in a similar way to antimicrobial stewardship, right. We all have to do our part.

Lisa Fortier:

Yeah, I was going to say the same thing.

Michelle Evason:

Yeah.

Sarah Wright:

All right. So, Michelle, thank you so much for sharing such a comprehensive background with our listeners. So, what are some of the important take-home messages from this JAVMA article?

Michelle Evason:

So I think the biggest thing is you know one is as mentioned already is raising awareness period, because I think a lot of veterinarians one may have sort of a limited comfort. It's sort of one of those funny things about the profession, right? Is I feel like the things like 80% of a general practitioner's day is in and around preventive care, right, like vaccination, talking about the importance of wellness testing, especially as animals get older, fecal testing, and yet I feel like a lot of us, myself included, really have fairly low understanding a lot of the time about what we're actually looking for and then some discomfort, especially when it comes to zoonosis, about communicating that. And so one, first and foremost, is raising awareness around GI parasites in general, particularly ones that are zoonotic like Echinococcus multilocularis. And then I think the other one is for folks out there that are familiar with Echinococcus multilocularis is sort of busting the myth that it is contained to these limited regions, right. And so we know now, based on our publication of 26 dogs where we've detected Echinococcus multilocularis, that actually we've detected this in dogs with no history of travel outside the country or outside the state or the province, and we've detected it in parts of the United States in particular where it's never been detected before. And so for people that thought, oh no, it's not coming here, it's not something I need to educate or speak to my clients about the importance of fecal screening and prevention, well, now we know that we have to, and so just to call those states out Colorado, you got it, Wyoming, Nevada, Montana, Illinois, especially Chicago, Washington, Idaho, Kansas, Oregon, it's there.

Michelle Evason:

So, we now know that there have been some studies in wildlife, so coyotes as well as fox that are finding it in places like Pennsylvania, as well as Missouri and Kansas. So again, we know it's there in these wildlife populations. But now we know beyond a doubt, through the magic of PCR, that it's definitely in pet dogs in these particular states. Canada, sort of the same thing, Alberta, British Columbia, Ontario that's not super new. We kind of knew it was there, we just didn't know it was there quite so much.

Michelle Evason:

But definitely this range expansion outside of the north and the west, where we thought it was, is a new thing and something to put on the things to talk to my clients about, especially in dogs that have any kind of wildlife interaction, which is another thing that we found in the paper. R right, is that most of these dogs, when we talk to the veterinarian and they talk to that pet owner, they did have contact with wildlife, and I think it's something. Again, back to the One Health that we sort of forget, right? Coyotes, raccoons, rodents, they're in our backyard and that's not just if you live on a farm in PEI, like I do, it's also if you live in the suburbs of Chicago. And so, again, sort of a broader conversation and something that we need to be thinking of more and more.

Lisa Fortier:

Yeah, I wonder, Michelle. You know we have that manuscript category called technical tutorial videos, so it'd be amazing if your team could put together like a mock. How do you talk to your client about this and how do you keep you and your kids safe and the whole environmental thing?

Michelle Evason:

I think it's a great idea and we are actually one of the things that we're planning for 2025 is to really have a big focus at our conferences and our education tracks on exactly that, because I think it is hard and actually, again, hats off to you folk. There's a study that I quote all the time that was around in and around zoonosis and veterinarians comfort speaking on zoonosis, right, and I think it's pretty low right, like, let's be honest, most of us get into this profession because we like the four legs, not because we love talking to the two leg. And so that next step like sometimes, although medicine is hard, sometimes taking that medicine and then having that conversation with the pet owner that can feel like the hard part. And big call out to my colleague, Jason Coe, another fellow Canadian, because he works a lot with myself I'm honored to do that and Jason Stahl as well, to take some of these concepts and spin them into something that we, as veterinarians, can feel maybe a bit more useful talking to pet owners about.

Lisa Fortier:

Yeah, for sure. Sarah asked you just a minute ago. Like some of the take home messages from, or you've been talking about the take home messages in the JAVMA, but every time you do these are these reviews and studies you find things that are absolutely surprising. What were those sorts of take homes from the JAVMA article that were surprising?

Michelle Evason:

No, it's really true. I think one of the ones and this is a little bit in the publication, but a little bit not is, again and again, when members of our consultation team reached out to speak to these veterinarians, how grateful they were for exactly what we were just talking about, because they felt very ill-equipped to have these conversations with pet owners. They also felt very unaware of what their role was in reaching out to public health. Right, and I think aconococcus multilocularis is a tough one too, probably because, again, there's that low level of awareness. It's not a parasite on an infection. When found, that's reportable in every state, or every province for that matter, and so there's a lot of confusion in and around what to do and how to move forward. The other thing that was in the paper was in and around risk factors for some of these dogs, and really there weren't outside of wildlife exposure, right. So it was basically every age category and every breed that we could think of, all the way from, like, a Datsun to a Bernese mountain dog, right, and so it really was related to were veterinarians doing fecal screening so that we could detect it, yes or no, and then, of course, finding it in these states that we had never found it. No one had ever found it for before. But really the importance of fecal testing is as part of the veterinary day-to-day and as part of preventive care.

Lisa Fortier:

What are the next steps in this broad area of research? Is it in developing a better antihelmetic? Is it easier identification, cage-side identification, so you don't have to send it away for a PCR. What's next?

Michelle Evason:

Yeah, these are really good questions and I really thought about that too, and I think one of the things is the PCR test that we use. It's usually back the very next day or sometimes either the same day. Key screen is quite affordable. I think a lot of folks don't realize that right, it's kind of on par with doing a fecal flotation and it also has a really fast turnaround time and so for most areas, even in Canada, it comes back to the veterinarian the very next day, and so a cage side or on site maybe, but again, I'm not sure on that. I think the other thing is that a lot of these dogs I definitely want to mention a lot of these dogs don't have clinical signs and actually, you know, that's one of the interesting things that we found with the, with this case series is that a lot of people would think because, again, dogs are the definitive host that they don't have clinical signs and actually about half of our dogs did have diarrhea. Hard to know if that was related to a multilocularis or not, but it.

Michelle Evason:

You know, your question in and around preventives and deworming is a good one, because right now most of the preventives that are available as an anti-parasite don't contain , which is, in fact, the drug that is needed to in Canada and the United States to treat Echinococcus multilocularis. It also touches on, you know, the antimicrobial and talmintic, in this case, stewardship, because I think right now you know. Should we be including in you know, routine preventives and I think there's some debate on that or should we be testing dogs and then making a decision to treat, because there are obviously spillover effects of using these drugs as a combo product too, and I don't have the answers to these questions, but I think you know to your question where do things go next? I think that is something that we do need to start looking a lot harder at on this side of the pond, in addition to what they're already doing on the other.

Sarah Wright:

That's fascinating. There's so many different things to consider, and you said that, Lisa

Michelle Evason:

I would never, ever have imagined I would be excited about GI parasites at the early point of my career. But you don't look and you don't know until you go looking, and then, when you find things, it can take you to places that you never considered, and so it's been really been interesting sharing this data with you know, the more academic community, like the infectious disease key opinion leaders, as well as the parasitologists, because I think we're starting to scratch the surface of what kind of recommendations we're going to make to the larger veterinary community, and I feel privileged to be part of that.

Sarah Wright:

Very cool, and to our listeners and those of you just joining us Very cool. And to our listeners and those of you just joining us. We're discussing emerging Echinococcus tapeworms in dogs with our guest, Michelle Eveson. So, Michelle, this next set of questions is going to be very important for our listeners. The first one is going to be from the veterinarian's perspective. So what is one piece of information?

Michelle Evason:

The veterinarian should know about Echinococcus tapeworms in dogs. Don't rely on fecal flotation, because it will not pick up Echinococcus multilocularis and I'm going to sneak another one in there. Be aware that it may be near you.

Sarah Wright:

So on the other side of the relationship, what's one thing clients should?

Michelle Evason:

Consider around Echinococcus in dogs. Listen to your veterinarian when they're making recommendations in and around preventive care with respect to compliance. Listen to your veterinarians. I will also say too and I think we all know this one wash your hands, pick up the poop, please also great and can be applied to a lot of different things, so thank you. Amen. You can't see it in the background, but Scott Weiss and I have identical matching signs that say don't eat poop, with a little poop emoji on them.

Lisa Fortier:

I recently submitted a fecal float for a friend that has a newborn pup, or you know, three month old puppy, yeah, and and puppy ends up with some a few different types of worms and they were completely freaked out and I was just like, yeah, wash your hands, it's not that hard.

Michelle Evason:

I, I, I know, but I also get it too Right, Because you're sort of it's kind of like ticks too. You're like, oh, it's gross like ticks too.

Lisa Fortier:

You're like oh it's gross, Michelle, as we wind up, I just want to say thank you again for education, re-education on on parasitology. Um, and for you viewers who can't see, Michelle has a clock in the background with cattails that are quite asynchronous. Uh, so I think I can guess the answer to this question that we like to ask. Not sure we've been wrong before, but when you complete a puzzle, Michelle, do you start with the exterior border pieces and finish that, or do you start with the inside?

Michelle Evason:

Oh, I'm an outside girl, 100% wrong.

Lisa Fortier:

I was like asynchronous is not going to be an outside OCD person.

Michelle Evason:

No, I am an outside, I'm a big picture person, and so I I always have to start out and then move in and how does that work with the rest of the family?

Lisa Fortier:

do they come and mess it up?

Michelle Evason:

it does not yep, it does not, but that that's okay, right, like then, we're balanced because we each have our, our separate areas that we work on.

Lisa Fortier:

Yeah, we also had it wrong, because most people who identify as an internist we find start with the inside and the outside is more like I'm a surgeon. So, yeah, no again.

Michelle Evason:

that's why I confess to being a closet criticalist. So I'm, I have, I, I, I almost went into soft tissue surgery. It was in your thing, Lisa and I still have some, some dear friends that are like ah, we were close.

Sarah Wright:

Yeah, it's a fun question. You never know People are going to say at some point we are going to share that, but it's. Thank you so much, Michelle. We appreciate you being here and talking about your article with us and also for submitting it to JAVMA.

Michelle Evason:

It's my pleasure. Thank you both for having me. How much fun was that.

Sarah Wright:

And to our listeners, you can read Michelle's article in JAVMA. I'm Sarah Wright with Lisa Fortier. Be on the lookout for next week's episode and don't forget to leave us a rating and review on Apple Podcasts or whatever platform you listen to.