Dengue and Oropouche infections are rising—what physicians need to know

The rising global burden of mosquito-borne viral infections has important implications for Canadian clinicians—particularly those assessing febrile patients returning from tropical and subtropical regions. On this episode of the CMAJ Podcast, infectious diseases specialists Dr. Maxime Billick and Dr. Stephen Vaughan explain what clinicians need to watch for as these viruses expand their geographic reach. Dr. Billick is the lead author of Five things to know about dengue, and Dr. Vaughan is the lead author of Five things to know about Oropouche virus, both published in CMAJ.

Dr. Maxime Billick describes the dramatic surge in dengue cases in 2024 and outlines the major drivers behind the virus’s global spread. She explains the urban-dwelling mosquito vectors that make dengue difficult to contain, discusses the virus’s four serotypes, and emphasizes the risk of antibody-dependent enhancement with reinfection. She reviews key clinical warning signs, diagnostic tests, and why identifying dengue—despite limited treatment options—still matters for patient counselling and care.

Dr. Stephen Vaughan introduces the less common but emerging Oropouche virus. He explains its current geographic range, including recent Canadian travel-related cases, and the role of biting midges in its transmission. Vaughan highlights early evidence of possible sexual transmission and the potential risks for fetal neurological complications if infection occurs during pregnancy. He also discusses symptom recurrence and what physicians should consider when counselling patients who may have been exposed.

Physicians should consider dengue and Oropouche virus in febrile returned travellers and prioritize preventive counselling before travel. Identifying the virus may not change treatment, but it can shape long-term risk awareness and help prevent future complications.

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Transcript

Dr. Mojola Omole

Hi, I'm Mojola Omole.

Dr. Blair Bigham

I'm Blair Bigham. This is the CMAJ Podcast.

Dr. Mojola Omole

So, today must be an emergency physician's dream come true topic.

Dr. Blair Bigham

Oh, I love talking about fever and the return traveler, Jola. You know that. And we've talked about it before, but today we're going to talk about two very specific viruses that we need to watch out for.

Dr. Mojola Omole

So, we're talking about dengue, which we've all heard about, but is on the rise. And another one that I'm still trying to figure out if I say “Oropuche” or “Oropooch”. 

Dr. Blair Bigham

I think they're both right, depending on where you are.

Dr. Mojola Omole

We'll find out when we talk to our guests. 

Dr. Blair Bigham

We'll ask the expert. And the reason we're talking about these two viruses is because they are growing in their geography.

Their range is spreading as their mosquito Arbo- vectors are also spreading. And so, it's more and more likely that we'll see these showing up here in Canada.

Dr. Mojola Omole

So, we have two papers that we're going to be talking to the lead authors on. Both are “Five things to know…”. One is about dengue.

And then the other one is about, as I said, “Oropouche” or “Oropooch”. 

Dr. Blair Bigham

We'll find out which. Coming up next on the CMAJ Podcast. 

Dr. Maxime Billick is an infectious disease physician at the University of Toronto and the lead author of the dengue “Five things to know…” article in CMAJ. And most importantly, she's a veteran of our podcast.

Welcome back, Maxime . 

Dr. Maxime Billick

Thanks so much. I'm excited to be here.

Dr. Mojola Omole

Are you done fellowship now? 

Dr. Maxime Billick

I'm done. It's been almost a year. And I'm wrapping up my master's in public health.

Dr. Mojola Omole

Congratulations. 

Dr. Maxime Billick

Thank you. 

Dr. Blair Bigham

We are very lucky that you've spent some time with us today.

Tell us, why now? Why are we talking about dengue now? Hasn't it been around forever?

Dr. Maxime Billick

It has been around for quite some time. The reason why I thought to write this paper was because 2024 was the highest number of dengue cases ever recorded. And it was really exponentially higher, significantly higher than it had been in previous years.

Dr. Mojola Omole

Do we know why? 

Dr. Maxime Billick

It's been rising over the last 10, 15 years or so. And I think the main drivers are multiple.

Climate change is a big one. So we're seeing the area that people get dengue in expanding. There's been more and more urbanization.

So people from the countrysides moving to cities, overcrowding, water being kept. We'll talk about this a little bit later, I'm sure, but water being kept near the home in places that don't have running water. And so really the thoughts are that those two main things are driving the uptick in dengue cases.

Dr. Blair Bigham

So I'm curious. I thought other mosquito-borne or arboviruses were going down in their incidence, like malaria. First of all, am I right with that?

And second of all, why is dengue so resilient? If other mosquito… Let me reword this. Are there more mosquitoes than there used to be because of these factors? Or is there something about dengue that makes it a resilient virus?

Dr. Maxime Billick

So we do see numbers in things like different types of malaria and sometimes certain years even Zika going down. We think that dengue is going up for a couple of reasons. So first of all, not all mosquitoes are the same.

So the vector for dengue, which is usually a mosquito called Aedes aegypti. Aedes albopictus is a second type that can also carry it or transmit it less frequently. Those mosquitoes are really, really great at living in cities.

They're daytime biters and they can survive off of very small amounts of water. So you'll see that people who keep water like in big barrels because they don't have running water, or if people collect rainwater in low and middle income tropical countries, if people have something as small as like a tire that's collecting water or even a bottle cap, the eggs of these mosquitoes have been found in those places.

Dr. Blair Bigham

So these are resilient mosquitoes compared to maybe like the anopheles, which only bite in the evening, I understand, and are maybe not as robust at spreading across geography as the Aedes mosquito.

Dr. Maxime Billick

I don't even know if they're less robust or more robust as compared to the fact that we are providing excellent habitats for them to replicate in. We're also giving them a huge population right there in these super urbanized, densely populated cities or slums for the virus to then be spread. 

Dr. Blair Bigham

And just remind us, what does the map look like? Where does dengue exist? 

Dr. Maxime Billick

So dengue exists worldwide in tropical and subtropical climates. I often get asked, can people get it in Canada? Can people get it in the U.S.? We generally say no. There has been some autochthonous spread, so person-to-person or person-to-mosquito-to-person spread, very intermittently in places like Florida, Texas, California, etc. But they do a lot of vector control, and so there's not sustained spread in those places.

The prime place that we see or the main reason why you would see someone infected with dengue in a place like Canada is because they have come back from recent travel. 

Dr. Blair Bigham

Got it. So this is almost exclusively in returned travelers. 

Dr. Maxime Billick

Yes, exactly. 

Dr. Blair Bigham

So I just want to go back to my days doing tropical medicine as a certificate.

And I remember that there are different serotypes of dengue. Does that matter? Do we need to know what type of dengue you have, or is it just enough to talk about dengue as a single disease?

Dr. Maxime Billick

So dengue, as you mentioned, has four serotypes. Once an individual has been infected with one of the serotypes once, it's thought that they can't get infected with that specific serotype a second time. But they can get infected with the remaining serotypes of the other three or the other two, etc.

Dengue is really interesting and a little bit mysterious. It is a virus that when inside the human can cause something called antibody-dependent enhancement. And that's a really sort of fancy, jargony term for saying that we have created some antibodies against dengue if you've already been exposed before, but those antibodies aren't enough to really stop the virus.

And so macrophages take in the virus, and then dengue, when people are infected, for example, a second or third time, is able to replicate inside the macrophages and cause an even more intense reaction sometimes.

Dr. Blair Bigham

So rather than get a little bit of immunity, you actually are primed up to have a worse dengue infection next time around? 

Dr. Maxime Billick

You got it. And it's usually thought that this happens with the second infection. We don't usually see it with the third or fourth. 

Dr. Blair Bigham

Oh, interesting. Okay.

Dr. Maxime Billick

It's not very typical to test for the serotype, although if people read studies, they'll talk about certain serotypes. But clinically, it doesn't make a huge difference, and we don't usually test.

There's some thought that perhaps infection with serotype 2 is a little bit more dangerous, but again, it's not super clinically relevant.

Dr. Blair Bigham

Speaking of clinically relevant, what buzzwords might a patient say other than I've just returned from a place with dengue, where you go, oh, dengue is on my differential?

Dr. Maxime Billick

Totally. So obviously, if they've had some mosquito bites, and they mentioned that, that's a bit of a given. Other things that are interesting about dengue, so retro-orbital pain or pain behind the eyes, muscle aches and pains, again, not really a buzzword that can apply to many things, but most people don't have a bad dengue infection or symptomatic dengue infection without aches and pains.

Things that you as a clinician would want to watch out for or would make your ears perk up a little bit are things like mucosal bleeding. So they're brushing their teeth and they're bleeding, they're getting their period, and it's way heavier than usual. If they have abdominal pain, lots of vomiting, those are all what we call warning signs of dengue.

Dr. Blair Bigham

And in your article, you mention severe dengue, you differentiate it. What are some of the red flags where a physician would say, oh, this is something that we need to watch, this might even need to be admitted to hospital?

Dr. Maxime Billick

The definitions of dengue have changed over the years. And so I think the most recent, if I'm not mistaken, was from 2009. So there's dengue, dengue with warning signs which are many of the things that I mentioned.

So abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, put a little asterisk there, I'm going to come back to it. Mucosal bleeding, lethargy, enlargement of the liver greater than two centimeters, and then increasing hematocrit from their baseline. On top of dengue with warning signs, then there's also severe dengue.

And that is really three main criteria. There's severe plasma leakage. And what that can look like is shock or like fluid accumulation on the lungs, usually in the form of pulmonary edema.

Severe hemorrhage or bleeding. So if people are vomiting blood, if blood's coming from the genitalia area in the urine or from the uterus with their period, their menses, hemorrhage in other places in the gums, in the mouth, in the eyes, uncommon. And then severe organ involvement, which is something like hepatitis.

So AST or ALT over a thousand. Neurologic changes, altered level of consciousness. And then findings like myocardial dysfunction.

Dr. Blair Bigham

Okay. So I should be able to pick this up and emerge with pretty routine blood work to at least cause me concern. They're going to say they're bleeding. They're going to look like they have plasma leak.

And they're going to have some sort of organ dysfunction on my lab screening.

Dr. Maxime Billick

Yeah. Clinically, the thing that I think is easiest to ignore and would just be worth highlighting is the abdominal pain or tenderness. That's something that sometimes we're like, oh, whatever, maybe it's not that serious.

Your other numbers are okay. But what that tells us is there's probably a degree of capillary leak inside the belly. And that's why patients are having pain.

And so in the case where you're questioning dengue, it's just one that I find is easy to ignore. And perhaps we should pay a bit more attention to if we're considering dengue on the differential. 

Dr. Blair Bigham

And then what am I sending off to confirm dengue?

Dr. Maxime Billick

It depends when the person is coming in. So usually symptoms of dengue present, if you read the literature, it says within 14 days. But it's almost always within a week.

So never say never. If someone comes day 10 after returning, sure, I would still send certain tests off and consider dengue on my differential. But practically speaking, if it's within seven days of being in a tropical area, that's when you'd really consider it.

If they present to you and have these symptoms within the first seven days of symptom onset, I should say, you want to send a PCR for dengue. You want to send an ELISA for something called NS1 or non-structural protein one. If that's positive, that's very indicative of a dengue infection.

And then you want to send IgG and IgM for dengue.

Dr. Mojola Omole

What's the turnover of ELISA and all these things?

Dr. Maxime Billick

Yeah, exactly. 

Dr. Mojola Omole

So sorry, go ahead. 

Dr. Maxime Billick

I was just going to say the IgG and the IgM can have some cross-reactivity with other arboviruses.

So you want to send the things off for dengue, but you also want to consider what else this could be, right? You always want to send for malaria if you're considering dengue. You can think of chikungunya.

You can think of oropouche. You can think of other arboviruses.

Dr. Blair Bigham

Zika. 

Dr. Maxime Billick

Zika, yes, thank you. Sorry, I forgot.

Dr. Blair Bigham

That's the only one on my list. 

Dr. Maxime Billick

The second thing that I'll say is that beyond seven days after symptom onset, you can no longer really do the PCR and the ELISA for NS1 is less accurate. So at that point, you'll just send the IgM and the IgG for dengue.

Dr. Blair Bigham

Got it. OK. And always the M and the G at the same time and see what comes back.

Now, how important is it to identify a dengue infection? Like, is there actually something we can do about it? Is there a specific treatment that an infectious disease doctor is going to get really excited about in the middle of the night?

Dr. Maxime Billick

Dengue treatment is mostly supportive. Of course, if people are having complications from it, then again, it's going to be sort of supportive, geared towards the complication in question. So if they're having heart failure or liver failure, your supportive management might change a little bit than if they just have dengue with warning signs, for example.

There's no treatment for dengue. The reason to identify it is twofold. One is to perhaps make yourself comfortable that it's not anything else life-threatening.

And then it's also to counsel the patient, right? Because if someone has dengue once, they might choose to conduct themselves differently if they're going to a tropical or subtropical climate in terms of protecting themselves against a second infection. 

Dr. Blair Bigham

Because their risk at that second infection might be higher.

Dr. Maxime Billick

Exactly. Their risk of having negative sequelae or outcomes of their second infection could be more dangerous.

Dr. Blair Bigham

So in addition to having a previous infection, who else is at risk of serious complications or a worse bout of dengue who we should keep our eyes out for?

Dr. Maxime Billick

We tend to think that people at the extremes of age, so young children, older elderly adults are at highest risk. And then your typical population that is at risk of other infections, so like those who are immunocompromised, who might have multiple comorbidities, etc. But there's no other unique at-risk populations.

Dr. Blair Bigham

And then for those people who are traveling, is there a vaccine or some sort of pre-travel advice that they should receive? I think I'm setting you up for something exciting to talk about.

Dr. Maxime Billick

Yeah, that's great. So I often get this question. And I love when people are already thinking about how to protect themselves before they travel, because oftentimes people who we see who come back from traveling haven't always sought pre-travel care.

There are several vaccines in the worldwide ecosystem. What I would say is that none are licensed in Canada, and they have variable efficacy. There is one that's had some negative consequences in children or adolescents, specifically because of what I mentioned earlier, that antibody-dependent enhancement.

So when given to someone who actually hasn't had dengue before, it sort of acts like a first infection. And instead of protecting them, it can actually put them at higher risk. And so there's no recommendations for travel-related vaccines with regards to dengue in Canada.

If people travel to other areas, they might find that locals are vaccinated for dengue. And there are some potentially exciting developments on the horizon in the next couple of years.

Dr. Blair Bigham

But for now, a vaccine for a traveler, not recommended. Even if you could get it wherever you're going, stay away. It could make your infection worse.

Dr. Maxime Billick

Yeah, and I'd say that for the type of person who's traveling a couple, two, three, four times a year, the risk is really different than for someone who lives in a dengue-endemic area. And the risks of a vaccine that isn't as effective as we would like it to be in that population might not be worth the trade-off. Whereas for someone living in that area who's getting dengue once a year, that trade-off might be more beneficial.

Dr. Blair Bigham

The calculus changes. 

Dr. Maxime Billick

Yeah.

Dr. Blair Bigham

So before we wrap up here, just give us the Coles Notes reminder. What should every physician be telling their patients before they head off to a dengue region?

Dr. Maxime Billick

So they should tell people to protect themselves against mosquito bites. And that is the best defense against acquiring dengue infection. And what that looks like is usually wearing light-coloured clothing, long pants, long-sleeved shirts if they can stomach it, or when they can stomach it, and then really using insect repellent, something that contains 30% DEET or 20% icaridin, 10% for children, and to use that frequently and to reapply.

That has been shown to decrease the risk of getting mosquito bites, which then decreases the risk of getting dengue infection. 

Dr. Blair Bigham

You can't get dengue if you don't get bitten. 

Dr. Maxime Billick

You got it.

Dr. Mojola Omole

But you can't have fun when wearing layers and layers of clothing.

Dr. Maxime Billick

Exactly. You know, like the light, breezy, kind of Mediterranean look.

Dr. Blair Bigham

Hang on, why light-coloured clothing? Are the mosquitoes, do they have a fashion sense?

Dr. Maxime Billick

They do, they do. Mosquitoes have a fashion sense. They are attracted to darker colours, and they don't, they're not as attracted to lighter colours.

So we usually say white or light-coloured clothing.

Dr. Blair Bigham

But doesn't that make you more susceptible to being attacked by some other animal? Because now you're not camouflaged.

Dr. Maxime Billick

Depends where you are.

Dr. Blair Bigham

Thank you so much for joining us today, Maxime . Thank you so much for having me. Thank you.

Dr. Maxime  Billick is an infectious disease physician at the University of Toronto.

Dr. Mojola Omole

We're going to move on to the next “Five things to know…” article in the CMAJ. This one is looking at, I can't say it right, “Oropuch-ay” or “Oro-putch” virus. Here to tell us about it first, how to pronounce it properly, and to tell us more about it, is one of the authors, Dr. Stephen Vaughan. He's a clinical associate professor in the Department of Medicine at the University of Calgary, and he's an infectious disease specialist with Alberta Health Services. Steve, thanks for joining us.

Dr. Stephen Vaughan

Thank you very much for having me today.

Dr. Mojola Omole

So how do we say it properly?

Dr. Stephen Vaughan

So my understanding is the proper pronunciation is or-a-poo-chay.

Dr. Mojola Omole

Or-a-poo-chay.

Dr. Stephen Vaughan

Yes, I've looked at a couple of different places and spoken to a number of different people and heard all of the different pronunciations, but this is the one that is, I guess, most approved.

Dr. Mojola Omole

All right. So Oropuche is rare compared to something like dengue fever. What should physicians be on the watch for now as we're seeing more cases being reported?

Dr. Stephen Vaughan

So with this virus, it really is relatively nonspecific in terms of its presentation. So we tend to see a traveller that comes back often with a febrile illness, and then typically we would work through the most common things that you would see, malaria, dengue fever, and some other illnesses. If we really didn't find something there or if they were travelling in an area where there was known Oropuche transmission, then talk to your friendly neighbourhood infectious disease doctor and we may send away some testing for this virus.

Dr. Mojola Omole

And what area should we be looking at in terms of the returning travellers?

Dr. Stephen Vaughan

So in Canada so far, there have been very limited number of cases. We've had a couple that have come back from Cuba because there was a relatively large outbreak there and Canadians love to travel in winter. One case came back from Colombia, but the hot bed right now and throughout this epidemic would be Brazil for sure.

Although really anywhere in the Americas could have this virus circulating at any time.

Dr. Mojola Omole

So how is it transmitted? Is it the same mosquito that we see that transmits the dengue? Are they the same species?

Dr. Stephen Vaughan

So it's not the same mosquito. So the Aedes mosquito is the primary vector for dengue, whereas this is a Culex mosquito. And in fact, they think that actually a small biting midge, which is, we often refer to them as no-see-ums or these little tiny bugs, they are thought to be the main way that this virus is actually spread between different vectors.

Dr. Mojola Omole

So how many cases have we seen in Canada so far?

Dr. Stephen Vaughan

So fortunately, we've only seen a handful of cases in Canada. I believe three have been reported in the literature. In the United States, there have been a couple hundred.

And in all of the Americas, I believe the case total is 20,000, something in that range.

Dr. Mojola Omole

And so is local transmission possible?

Dr. Stephen Vaughan

So fortunately for us in Canada, we don't have that particular species of mosquito, although we have some relatives. So we don't think that they are likely to be able to transmit, and we haven't seen any local transmission in Canada. Same with that midge.

It's not adapted to our colder winter climate.

Dr. Mojola Omole

And what about something like sexual transmission that you can get with Zika?

Dr. Stephen Vaughan

That's a great question. And it's a really sort of interesting topic right now. So one study did notice that the virus was present in semen out to about 58 days after exposure.

But just because they could find the nucleic acid, they weren't actually able to cultivate active replicating virus. I think day 16 is the longest after exposure that they've been able to cultivate it. But theoretically, there may be a possibility of sexual transmission if someone comes back from an endemic area.

Dr. Blair Bigham

How far out from returning from travel or from being in an endemic area can Oropuche start to become symptomatic?

Dr. Stephen Vaughan

So similar to other mosquito-borne infections, it's very acute in terms of its presentation. So usually within 14 days after leaving an endemic area would be the outside window. Very commonly, it can be within 2 to 7 or 10 days.

Once you get outside of that window, it's far less likely.

Dr. Mojola Omole

Is it possible for it to recur?

Dr. Stephen Vaughan

It is. And that's actually an interesting point. Most mosquito-borne viruses, once you recover from them, as long as you've had full symptomatic improvement, that's the end and you just go on.

The early reports for Oropuche have shown that up to 60% of people can have recurrent symptoms. So the fevers, chills, myalgias, after having what looks like full recovery. Now usually that just occurs within the first month and then won't occur later after that.

Dr. Blair Bigham

So I guess I'm curious, what about Oropuche makes it have this relapsing feature?

Dr. Stephen Vaughan

Again, that's a great question. I don't think... It's a mystery.

I don't think we know. And because we haven't seen enough cases, we're not sure if the patients actually become viremic again or if it's more of an actual autoimmune phenomenon that occurs after. That really hasn't been studied, but both hypotheses have been presented.

Dr. Mojola Omole

So how serious can you... How seriously sick can you get with Oropuche?

Dr. Stephen Vaughan

So you can get seriously ill. It tends to be less common than seen with dengue fever, probably by at least an order of magnitude less. So I think last year, direct deaths related to Oropuche were, I think there was four that were definitely caused by the virus. I think the greatest concern is similar to Zika virus, where you can have a pregnant patient who becomes infected, transmits the infection to their unborn fetus, who can become infected and have significant neurologic abnormalities.

Dr. Mojola Omole

Okay. And so first, how do we diagnose it?

Dr. Stephen Vaughan

So diagnosis primarily is through nucleic acid testing, so PCR-based testing of blood and urine. That would be the easiest way to detect the virus, and that can be done usually during the symptomatic phase. That's when the patient's viremic.

If they presented a little bit late, then you could consider sending serologic testing, so blood tests for antibody IgM. That would have to be done through the National Microlab in Winnipeg, and the turnaround time would be significantly delayed.

Dr. Blair Bigham

So are either of those tests something that I'm going to be ordering either in a family clinic or in an emergency department?

Dr. Stephen Vaughan

I don't think you would be ordering this test routinely. Likely you would...

Dr. Blair Bigham

Like, I don't have to add it to my usual, like, test for malaria, test for dengue, test for chikungunya.

Dr. Stephen Vaughan

Depending on the testing that's done for your arboviruses, so for dengue and chikungunya, we routinely do PCR testing on both blood and urine. And so all we would have to do in our lab is just call our lab. They would pull the old specimens and then be able to run them for the different virus.

If you're not routinely doing PCR testing, that's when you might want to consider other storing samples or just discussing with infectious diseases the best way to make the diagnosis.

Dr. Mojola Omole

And how do we treat it?

Dr. Stephen Vaughan

So treatment is really supportive. There's not much that we can do for these patients. We generally recommend avoiding non-steroidal anti-inflammatories because we know in other infections such as dengue, they can have bleeding complications, although that hasn't been directly reported with this virus.

But analgesia with Tylenol is fine for symptomatic management. If someone became dehydrated, then fluid resuscitation and just gentle fluid resuscitation because we do know third spacing can be a complication of certain mosquito-borne infections.

Dr. Mojola Omole

Do you think there's going to be vaccines available in the development for this, re any on the horizon? Or is this just the numbers are not necessarily there, the way they are like with the chikungunya and the other ones?

Dr. Stephen Vaughan

So I don't think at this point that there is any research on vaccines that I'm aware of. I think you're right. Due to the low numbers, I think right now probably wouldn't be profitable from a pharma perspective.

But if the numbers continue or continue to increase, then definitely. And we have seen vaccines that have become available in many countries for dengue, for chikungunya, even Zika vaccines are in development right now. So the technology exists.

Dr. Mojola Omole

For sure. And so what should physicians be telling their patients who are traveling to where Oropuche is circulating?

Dr. Stephen Vaughan

I think the best advice is to take precautions with regards to mosquitoes. So that means using a product with an insecticide, so such as DEET or Icaridin, Picaridin are the common ones that are available in Canada. If you were going to a highly endemic area, such as the Amazon rainforest in Brazil, then you would be wanting to take things like insecticide treated clothing.

So you can get permethrin treated clothing. You'd want to wear long sleeves and sleeping under a bed net, those sort of precautions. But for most travelers, just general precautions would suffice.

Dr. Mojola Omole

Okay. Thank God I don't want to go to the Amazon. Thank you so much for joining us today.

Dr. Blair Bigham

This is very cool stuff. Thanks for joining us.

Dr. Stephen Vaughan

No problem. This is very cool for me too. And any way that we can get this information out, I think is helpful.

And yeah, this is awesome.

Dr. Mojola Omole

Dr. Stephen Vaughan is a clinical associate professor in the Department of Medicine at the University of Calgary. And he's an infectious disease specialist with Alberta Health Services. Blair, you're the merge doc.

Fever in the... Unknown fever in the recent traveler is kind of your catnip. What were your initial thoughts?

Dr. Blair Bigham

I think this is fascinating. I think it always is a struggle to understand like why this is relevant when the care is often supportive. But I think for each of these viruses, we have some unique features that might matter to patients.

So for dengue, if you get dengue once, you might not want to get it twice. It could be even worse. In some cases, way worse.

I remember from my time at London School of Hygiene, that the study that Maxime was talking about, where they tried immunizing children against dengue, like children actually died more frequently from dengue because of it. So this idea of a second hit being much worse, it's not just like you have fever and chills, like you can die from dengue. So yeah, I've had one actual pickup of a patient who was serology positive who ended up dying on life support from advanced liver failure.

So just like really, really consequential. And so knowing if somebody had dengue is important. And here we have a way to do that.

So making sure that just like I think everyone takes malaria exceptionally seriously in a return traveler with fever, making sure that other viruses like dengue, like chikungunya, are on your radar and that you're testing for them. Because even though there's no magic silver bullet that's going to make someone better, it is important to know which virus is causing their symptoms.

Dr. Mojola Omole

Yeah, and then for us to continue to discuss with our patients who are traveling, you know, smart tips about wearing light clothing and wearing... I always thought DEET was bad for you, 

Dr. Blair Bigham

It is but I think dengue is worse. But this idea that, yeah, because it's all supportive care, yeah, we do need to prevent the infection, prevent the mosquito bite right from the get-go. And that maybe is counseling that can take time, but counseling and, you know, often I think counseling that gets ignored. But maybe we need to come up with better ways of communicating the imperative for people to undertake mosquito avoidance while they're traveling.

That’s it for this episode of the CMAJ Podcast. The link to the study is in the show notes. Please rate, share or review our podcast wherever you can. It helps us get the message out. The CMAJ Podcast is produced by Neil Morrison and PodCraft Productions. Dr. Catherine Varner is our deputy editor at CMAJ. I’m Blair Bigham

Dr. Mojola Omole

I’m Mojola Omole, until next time, be well.