Today, Explained - Dengue’s biggest year ever

Episode Date: July 23, 2024

More than 10 million people worldwide have contracted dengue from mosquitos this year. Now experts are worried it might show up at the Olympics. This episode was produced by Amanda Lewellyn and Peter Balonon-Rosen, edited by Matt Collette, fact-checked by Amina Al-Sadi and Laura Bullard, engineered by Patrick Boyd and Andrea Kristinsdottir, and hosted by Sean Rameswaram. Transcript at vox.com/today-explained-podcast Support Today, Explained by becoming a Vox Member today: http://www.vox.com/members Learn more about your ad choices. Visit podcastchoices.com/adchoices

Dengue is known as break bone fever because people who have dengue can feel intense pain, like if their bones are breaking. But people also feel nausea and vomiting, rash, aches and pains. And the symptoms typically last two to seven days. Most people will recover after about one week and there are some signs and symptoms that suggest that a person may be developing severe disease they are severe abdominal pain repeated vomiting bleeding from the nose or the gums vomiting blood or blood in the stool and feeling irritable.

Dengue can be severe and can be fatal if he's not treated appropriately. Dengue is having its biggest year in history, and we're going to find out what we can do about it on Today Explained. Bet MGM, authorized gaming partner of the NBA, has your back all season long. From tip-off to the final buzzer, you're always taken care of with a sportsbook born in Vegas. That's a feeling you can only get with Bet MGM. And no matter your team, your favorite player, or your style, there's something every NBA fan will love about Bet MGM.

Download the app today and discover why Bet MGM is your basketball home for the season. Raise your game to the next level this year with BetMGM, a sportsbook worth a slam dunk, and authorized gaming partner of the NBA. BetMGM.com for terms and conditions. Must be 19 years of age or older to wager. Ontario only. Please play responsibly. If you have any questions or concerns about your gambling or someone close to you, please contact Connex Ontario at 1-866-531-2600 to speak to an advisor free of charge. BetMGM operates pursuant to an operating agreement with iGaming Ontario. Today Explained, Sean Ramos-Verm here with Dr. Gabriela Paz-Bailey, chief of the Dengue branch at the Division of Vector-Borne Diseases at Centers for Disease Control and Prevention.

Yeah, we're very lucky to be based in San Juan, Puerto Rico. Cool. Why lucky? Because it's like tropical and fun? Yes, and we have the Caribbean Ocean 15 minutes away. But you're not just based there by choice. It's for professional reasons. Is that what you're saying? Yes. I mean, dengue is common in Puerto Rico. So we're based here. We work very closely with the local health department and with the mosquito vector control unit. So we're based here. We work very closely with the local health department and with the mosquito vector control unit. So we can conduct research and surveillance here, but also support the global dengue work. Tell me what kind of year dengue is having.

Yes, this has been a very big year for dengue. 2023 was the record year in the Americas. Rates of infection have gone up eightfold since the year 2000. Climate change is to blame. 4.5 million cases were reported, but in the six months of 2024, already more than 10 million cases have been reported in the Americas. Double. Double in the six months of what been reported in the Americas. Double. Double in the six months of what was reported for the entire year in 2023. Just days ahead of Carnival, with millions of tourists expected,

Brazil is on high alert amid a surge in cases of dengue fever. Brazil is responsible for most of the cases in the Americas. Eight of the 10 million have been reported from Brazil. With Brazilian health services already under strain, field hospitals have sprung up in the capital and other cities across the country. I have been feeling this pain for four days. I can't even raise my head because I feel like I'm going to faint. There have been outbreaks reported in many, many other countries. Bangladesh is well used to dealing with dengue fever,

but this year is something else. This year's rainy season has seen a record number of cases here in Nepal. The same is happening in parts of Africa where outbreaks are being reported. There were 23 countries with outbreaks last year, and 13 countries have reported transmission this year, and also in Asia and in other parts of the world. The interesting thing is that it's also occurring in areas where we didn't see dengue before. Like, for example, France has reported locally acquired cases, Italy, and parts of Spain. France? That's right.

They're about to have the Olympics. Yes. Sorry. Okay. Okay. So dengue is the worst it's ever been in recorded history. That's what you're telling us. Yes.

This year, 2024, has surpassed all previous records in terms of numbers of cases. And we're seeing it in places we've never seen it before. Yes. How is this happening? Why is this happening? That is a very good question, Sean. And there are several reasons for this. One of them is the changes in climate. Dengue is a mosquito-borne virus, so it has been a warm and wet year, so there are a lot of mosquitoes around. And mosquitoes are also thriving in more places thanks to climate change. The increases in temperature and in rainfall create ideal conditions for mosquitoes.

The second reason is that dengue is cyclical. There are large dengue outbreaks every couple of years. And part of the reason for this is that dengue is caused by any of the four different but closely related dengue viruses. Dengue 1, dengue 2, dengue 3, and dengue 4. And people who get one type of dengue are protected for a couple of years, but they are susceptible to getting another type. The third reason is travel. People are traveling more.

During the time of the COVID pandemic, there was less travel and mobility of people, and that limited the movement of the virus as well. But humans help the virus move around. And finally, mosquitoes are incredibly persistent and will lay their eggs in any place where there is standing water. So this could be in the vent pipes of septic tanks, in water meters, in old tires, in broken flower pots, basically anywhere

where water collects. So how much of a problem has this been in a country like Brazil, let's say, where they've had the most cases of dengue this year, in this record-breaking year? Is it disrupting daily life? They have had a record outbreak with more than 8 million cases reported. Brazil is very good at clinical management. They do regular trainings for clinicians and clinicians are very familiar with treating the disease. So they have been very successful at keeping fatal cases very low. Our goal is to greatly reduce the number of hospitalized patients

and have zero deaths from dengue fever. And they are also using different strategies. They have implemented vaccination with the recently recommended Takeda vaccine from WHO, and they're also using novel strategies to control the mosquito. Early morning is the best time to release mosquitoes. The ones in these cylinders have been bred in the laboratory and infected with a certain kind of bacteria while back here. That makes them incapable of transmitting diseases like dengue fever.

So they're really hitting the mosquito with everything they can. You mentioned vaccines. Sorry, is there a dengue vaccine or are they using other vaccines to treat dengue? There are dengue vaccines that have been approved in the United States. There is only one dengue vaccine approved. It's called denvaxia. Envaxia? Like Nile? Denvaxia. Oh, that makes sense. Denvaxia. Denvaxia. Oh, that makes sense. Like dengue.

Denvaxia. Yes. So, Sean, the denvaxia vaccine is recommended for children ages 9 to 16 who have had dengue before. So, that vaccine is only recommended for people who live in areas where dengue is common. So, it's being used now in Puerto Rico. There is another dengue vaccine developed by Takeda. It's named is Kidenga.

And that is a vaccine that is currently being used in Brazil and in other countries like Argentina and Indonesia. It sounds like people in Brazil might be used to dengue by now. But what about all these places that dengue is traveling to? You mentioned Western Europe. I mean, has it landed in the United States yet? Yes, there have been dengue cases in the continental United States. They have been reported from Texas.

At that time of the year, mosquitoes are swarming East Texas. Florida has locally acquired cases every year. Hawaii has had dengue outbreaks. The dengue fever outbreak on the Big Island started back in September, and it isn't over yet. And more recently, new states like Arizona in 2022, they had two locally acquired dengue cases. And California in 2023 also reported two locally acquired cases. And the issue is that with the increases in travel over the summer, there will be more people that acquired dengue when traveling to areas where there are dengue outbreaks occurring. And then when they come back to their homes, they can be bitten by a local mosquito that will acquire the disease and that can start small chains of transmission in the places in the

U.S. where the Aedes mosquitoes are common. Already in the first six months of 2024, we have seen double the number of travel-associated cases that we saw for the same period last year. In the case of Puerto Rico, a public health emergency has been declared because of the dengue outbreak. Usually the first part of the year is low season, but we have been seeing an increase in the number of cases that continues to increase. So I cannot tell you how large the outbreak is going to be, but we do expect for the cases to continue increasing over the summer. So how worried should we be in places where dengue isn't, you know, the norm? Yeah, I think it's important for people to know that dengue is becoming more common for all of us to talk more about dengue and for clinicians to think that dengue is becoming more common for all of us to talk more about dengue and for

clinicians to think about dengue when they have a patient with fever who has traveled to an area where dengue is common and to test for dengue with the appropriate tests and then for people to take steps to protect themselves against the virus when they're traveling. And what they can do is to wear insect repellents, to wear long sleeves and long pants, and if possible, to stay in areas with air conditioning and with screens. Okay, I hear you on the protection, but you're also saying wear long sleeves and long pants in hot places that also might not even have air conditioning. Yes, I think that ideally we will have a vaccine that is available for more age groups than

the one that we currently have. But in the meantime, we need to use the methods that we have available to protect ourselves. That includes using long sleeves and pants, even if the weather is hot, and wearing repellent if you can. Okay. I'm going to leave it there, but it's so hot in D.C. I cannot imagine wearing pants right now. So you're wearing shorts. I'm wearing shorts. You can't see them, but I'm wearing shorts.

They're very short. That was Dr. Gabriela Paz Bailey in Puerto Rico, where she works for the CDC. That thing she said about France had us wondering if dengue could be an issue at the Olympics. Turns out we're not the only ones wondering. So we're off to Paris when we're back on Today Explained.

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freedoms. This Giving Tuesday, you can support the ACLU. With your help, they can stop the extreme Project 2025 agenda. Join the ACLU at aclu.org today. Some people are really into mosquito-borne diseases. Brilliant. It's my favorite topic, so I'm happy. Like this person. My name's Marianne Comperet, and I'm the director at the International Society for Neglected Tropical Diseases, based in the UK. Neglected tropical diseases. It sounds so sad and yet important. Absolutely. So there's about 20 plus diseases on this list. And you might actually be surprised to know that despite being

neglected, they actually affect over 1.6 billion people worldwide. So I just always like to start by saying that neglected does not mean rare and these are actually extremely prevalent diseases that affect a lot of people in already quite challenging contexts and why are there some diseases that don't get as much love than others you might just say that it comes down to market forces i think the populations that are at risk or affected don't necessarily represent a viable commercial base. Also, they're often communities with very little political voice. Sad. So basically brown people. A kind of spectrum. In our very globalized world, I think these issues really know no borders,

and we're really kind of starting to see that. Okay, so economic factors, market factors affect which diseases are neglected and which ones get lots of attention. But one thing that gets lots of attention, Marianne, is the Olympics. And I've heard a nasty rumor that there could be dengue at these Paris Games. Is it true? I'm afraid that, yes, it's probably on balance going to be true. Unfortunately, the Olympics being really a huge event, bringing over 15 million people in one place could certainly represent a hotspot for dengue. So, particularly with regards to Olympics in Paris and in France,

France has been keeping a very close eye on dengue. For the first time in Paris, a mosquito control operation. At the end of 2023, for example, there was a case of dengue reported in someone who had never traveled abroad. An insecticide sprayed on all the green spaces, all around the building where a dengue patient lives. And against the backdrop of increasing presence of the right kind of mosquito, increasing numbers of cases across the whole French territory. Of course, this has, combined with the Olympics, put this very high up on the radar of the organizing authorities. The viral infection doesn't spread from human to human,

but through tiger mosquitoes capable of carrying the virus. If I get bitten and then my neighbors get bitten, they'll get infected. Then there's a risk of transmission and an epidemic. And in the 11th hour, I have to ask you, I say dengue, you say dengue. Is it like tomato, tomato? Yeah. Beautiful. Do we know how dengue got to Paris in the first place? So it's probably been following a trend that's sort of resonating around the world with the changing climate and increases in average temperatures worldwide. These mosquitoes have found very comfortable homes in new areas.

It's not just France that has the Aedes mosquito, which is the one that can spread dengue. It's also a lot of neighboring countries, whether that be Spain and Belgium, even Switzerland. So really, this isn't specifically a French problem. It is an international problem. The tropical species also taking hold in 13 other European countries. As the climate warms, scientists say that many places are

becoming more hospitable to mosquitoes. There's going to be a huge influx of people in Paris. Does that mean that there's any greater risk of this disease spreading? That's an excellent question. And in a way, you kind of have to imagine it as a scale. So on one side, there are the factors that are making this worse. And on the other side, there are the factors that are mitigating the risk. So let's say on the hazards, yes, there are upwards of 15 million people expected, so people coming from all around the world. Now, simultaneously, dengue fever in the rest of the world has just taken on a completely disproportionate level this year.

On the plus side, however, French authorities have been really keeping an eye on this. They have been monitoring the mosquito, they have been trying to get rid of all the breeding grounds, they're really monitoring that very closely. It's a vacuum for insects. When a mosquito lands on me or on the vegetation, we try to catch it. We can then identify the species. They also have a very impressive system put in place over the last two years, really. They've been working on it to make sure that any such public health risk is contained and

mitigated. What is most important is trying to eliminate the living places of mosquitoes, that is to say bins, buckets, clogged gutters or even flower vases. Whether or not that means that a dengue outbreak will happen, won't happen, only time will tell. I think we can only find out as and when the Olympics unravel, but certainly everything is in place to make sure that should it happen, the response is already there. You know, down to little things like Olympics taking place in July and August, which are traditionally months when a lot of French people might take their summer holidays for extended periods.

They've looked at reporting systems to make sure that 999 calls are kind of consolidated in one place. I feel quite confident. Actually, just recently, I managed to get a few tickets for the Olympics. So I can tell you firsthand. You're going. I'm going. I couldn't believe it. That's exciting. Which sporting event will you be attending? Athletics.

Okay. Is that indoors or outdoors? It's open air, yes. And we'll be the really tiny dot right at the top, right on the last row. But we will be there. Are you taking precautions to make sure you don't get bit? Will you be on the last row but we will be there are you taking are you taking precautions to make sure you don't get bit will you be on the prowl for mosquitoes i will not be able to look at this event without my dengue lens on i would make sure i wear insect repellent um you know just in case and just take normal precautions which i think we all might do if we're in a big crowd anyway. Do you think dengue being on this like global stage at the Olympics

will do some good in terms of the thing we opened up talking about this neglected designation that it has? So I've been reflecting on that a lot. And I have to say, when it comes to these diseases, every little bit helps. And it's certainly been very important to have something like dengue fever feature in headlines, whatever the route to get there. We have to remember that in 1970, dengue was in nine countries. And somehow over the next 50 years, it kind of surreptitiously has popped up in 120. And now it's a disease that has been escalated by WHO's emergency department, for example, to its highest risk level. And yet lots of people might still be surprised to hear that

it exists, that it exists outside of tropical regions, and that it's actually the fastest growing mosquito-borne disease in the world. And we don't know necessarily where it might go next. And therefore, having it somewhere like the Olympics is, in terms of advocacy, a positive thing, as long as the authorities, of course, have put everything they can in place to mitigate any risks, which I feel has been done. Whilst it's really great that people are taking it seriously now I think it's a shame that it took so long because outbreaks have occurred in places where they hadn't occurred previously and whilst the fatality rate's quite small compared to other diseases, that still means a lot of unnecessary deaths.

Even without the fatalities, it causes quite a huge burden on families and people affected in terms of their productivity, their ability to earn. And the big lesson here is really that time wasted with diseases of epidemic or pandemic potential translates into a huge amount of avoidable suffering in communities. And so I think that's the slight regret that I have when it takes this long for a disease to come to the forefront. But hopefully we've learned to not do that anymore. The pandemic, the COVID-19 pandemic, has really opened our global ears to all these issues. So I am hopeful for the future.

Have a great time at the Olympics. Be safe. I hope so. It'll be a once-in-a-lifetime experience, as they say. Marianne Comperet is director at the International Society for Neglected Tropical Diseases, but she's trying to change that neglected part. So is Amanda Llewellyn. She produced the show today with help from Peter Balanon-Rosen. We were edited by Mosquito Matthew Collette, fact-checked by Amina Alsadi and Laura Bullard, and mixed by Patrick Boyd and Andrea Christen's daughter.

On Friday, we're going to talk about Breaking's Olympic debut on Today Explained. Thanks for watching!