The future of mosquito-borne diseases

Transcript

Russ Altman (00:00): This is Stanford Engineering's, The Future of Everything. And I'm your host, Russ Altman. If you enjoy The Future of Everything podcast, please subscribe or follow on your favorite listening app. It helps us and you'll hear about all the episodes as they come out today. Professor Erin Mordecai will tell us about how climate change is influencing human health.

(00:23): It turns out that mosquitoes transmit lots of diseases, especially viruses, and as temperature increases, the mosquitoes do better or less well depending on what the temperature is. This is changing the geography of many diseases with areas that never had a disease, having more and more of it and some areas actually having decreased disease. This is including areas of the United States. It's the future of mosquito-borne diseases.

(00:52): Before we jump into this podcast, let me ask you to please rate and review it. It helps us improve and it helps spread the word about The Future of Everything. Many of the most scary viruses are transmitted by mosquitoes. This includes malaria, Dengue, Zika, chikungunya, and many others. That's not even to mention the diseases transmitted by other insects like ticks.

(01:16): The geography of these insects is rapidly evolving in response to climate change. Some regions that haven't seen malaria in a long time are seeing an uptick, no pun intended. Other areas are saying the rates of malaria actually go down. These changes raise substantial health concerns and challenges for policymakers trying to figure out how to manage all this.

(01:39): Erin Mordecai is a professor of biology at Stanford University and an expert about how climate, species and infectious diseases interact to create a dynamic set of health challenges. She'll start by telling us how climate impacts human disease through the simple fact of altering mosquito populations.

(01:59): And she'll tell us that in some areas we're seeing more malaria, in other areas it might be going down. But don't get too excited because there are other diseases that seem to take Malaria's place. Erin, thanks very much for being with us. Your work highlights how changes in climate can lead to changes and effects on infectious disease. Can we start out by just connecting those two dots? Because I don't think people think about climate and their diseases as intricately linked.

Erin Mordecai (02:27): That's right. If you have been living through the pandemic like we all have in the last few years, you probably think that infectious disease is all about coming in contact with people, being in a room with someone who is shedding virus from their breath and causing you to get infected. And that's part of the story, but the other part of the story is that the viruses or parasites or bacteria or other organisms that cause disease often have a life cycle that happens entirely outside of humans.

(02:54): Either they're resting on surfaces, like for the case of some viruses or sometimes they're actually cycling through mosquitoes or ticks or flies or other organisms, and sometimes they even have reservoir hosts that are things like mammals, like bats or rodents or other animals. And so those diseases that cycle through parts of their life cycle outside of humans have this intimate connection with climate because the climate is affecting everything about their life cycle.

(03:21): It's affecting how quickly the mosquitoes that transmit diseases can reproduce and how often they bite and when they bite, how likely they are to actually pick up parasites and be able to transmit them to the next person. And of course, things like rainfall affect how many mosquitoes are there because it affects how much breeding habitat there is for mosquitoes.

(03:40): So in particular, most of our research focuses on mosquito and tick-borne diseases, and these are diseases that are very closely tied to climate. We see very clear signals geographically of where these diseases occur being tied to climate, and also over time when these diseases start to peak depends on the temperature and rainfall during the season.

Russ Altman (03:58): So this is great. So can you remind us, when we think about mosquitoes and we think about ticks, which diseases are we basically thinking about?

Erin Mordecai (04:07): We're thinking about tick-borne diseases are like Lyme disease and Babesiosis and some other really interesting parasitic and bacterial diseases. And then mosquito-borne diseases are things like West Nile virus, Zika virus, Malaria, which is caused by a parasite, Dengue virus. And there are actually many, many different mosquito-borne diseases.

Russ Altman (04:27): So I guess I have to ask here in 2023, does this stuff have to do with our favorite virus, and I say that jokingly, COVID. Is part of this whole pandemic related to climate change at all.

Erin Mordecai (04:43): Well, SARS-CoV-2 is not transmitted by vectors like mosquitoes or ticks. It is thought to have a wildlife reservoir host, which means-

Russ Altman (04:51): I've recently been hearing about raccoon dogs.

Erin Mordecai (04:53): Yes. So that's one of the things that we think might carry SARS-CoV-2 or something closely related to it in the wild. At some point that virus crossed over from animals into people. And now of course it's highly capable of spreading from person to person. Interestingly, it can also spill over into deer and big cats and lots of other animals that we've detected. But in terms of SARS-CoV-2, most of the transmission that humans experience comes from other humans these days.

Russ Altman (05:22): Yes. Okay.

Erin Mordecai (05:22): There is still a climate component because like many other respiratory diseases you know, there's the flu season and the cold season, it happens during the colder part of the year in part because of lower humidity and in part because of human behavior that brings us together indoors and causes us to sneeze and breathe all over each other during the winter when we all get sick.

Russ Altman (05:40): Right. Okay, good. I'm glad I asked just to make sure that. So let's go back to our mosquitoes and our ticks. So yes, so you did make that connection beautifully. And now I can see that obviously these bugs because anybody who has lived in any kind of climate knows that there's a seasonality to when the bugs are appearing. I actually killed a mosquito in my bathroom this morning and I'm in northern California and we have had rain for the last... And so I was very shocked by that. And I'll talk to you off camera about what that means and whether we have a big problem.

Erin Mordecai (06:16): Whether you should go to the doctor?

Russ Altman (06:16): Yeah. Yeah. Or if it's a mosquito. I probably should have saved it. I mean, a termite. Okay, I'm sorry. Let's focus. How sensitive are these mosquitoes and ticks to changes in temperature? Because we hear about global warming and I think some of your work has addressed that even their habitats are changing over time. What have you found?

Erin Mordecai (06:39): That's right. Mosquitoes are extremely sensitive to temperature. We'll start there because it's kind of a simple answer. If you take a mosquito and put it in the lab and put it in an incubator and rear it at 25 degrees Celsius or 30 degrees Celsius or 15 degrees Celsius, I should probably be speaking in Fahrenheit here. So we're talking temperatures between let's say 50 or 60 degrees Fahrenheit up to about 90 degrees Fahrenheit.

(07:02): It has huge consequences for the mosquito. These mosquitoes that are raised at high temperatures will come out more quickly from their larval habitat, but many more of them die. They come out smaller also. They bite more frequently and they're able to develop the parasite more quickly. So the parasite life cycle within the mosquito, you might think, "Oh, this mosquito is like a flying syringe. It just goes around, takes blood from one person, puts it into another, and that's how it transmits parasites."

(07:28): That's not actually what happens. What happens is the mosquito needs the blood meal. Females only need this blood meal to make eggs. If this blood meal that they take from one person or one other vertebrate has some sort of parasite or virus in it, rather than the normal thing that would happen, which is that that parasite just gets digested and excreted out of the body, somehow the parasite has to be able to break through the mid-gut barrier of the mosquito. And then it disseminates throughout the body of the mosquito, replicates, eventually binds to the salivary glands.

(07:58): So you may know that the reason mosquito bites itch is because the mosquito's injecting a little bit of saliva as an anticoagulant, and that's the thing that your body forms an allergic reaction to. And it's that saliva that can contain those parasites and viruses that then transmit the disease. But for this whole process to happen, there's sort of a development cycle that has to take place within the mosquito. And how fast that development cycle happens is extremely closely linked to temperature.

(08:22): So it can be anywhere from a day or two all the way up to several weeks. So when the temperature is too cold, the mosquito can't really transmit parasites and viruses very well because it takes too long for the parasite to get through this incubation cycle. But on the other hand, when the temperature is too warm, the mosquito dies so quickly, it's not able to survive as an adult for very long that it's not able to go around biting many people before it dies. So it's not a very efficient vector at very warm temperature.

Russ Altman (08:49): Okay, so that was actually, thank you because that indicates a couple of follow-up things I want to ask you. So the last thing you said about how when it gets too hot then they can't also thrive. Does that mean that there are areas that have had for many, many years or even centuries endemic malaria and other diseases that are now starting to see less of it because of the habitat getting too hot?

Erin Mordecai (09:13): This is a really great question, and that actually gets to one of the key results of some of our research, which is if we look across the whole mosquito life cycle and the whole malaria parasite life cycle, we can measure in the lab how they respond to temperature. And when we do this, we put it together into a mathematical model that turns these lab experiments into a prediction of how transmission responds to temperature.

(09:35): And we find that transmission of malaria peaks at 78 degrees Fahrenheit or 25 degrees Celsius. That may come as a surprise because you probably think of malaria as a tropical warm weather disease, but actually 78 degrees Fahrenheit, we experience that here in the Bay Area in the summer sometimes.

Russ Altman (09:52): That's kind of the dream for humans.

Erin Mordecai (09:54): Right? It's really nice and comfortable. And as you get above 78 or 80 degrees Fahrenheit or about 25 to 25 degrees Celsius, the temperature starts to be too hot for optimal malaria transmission. So as you might imagine, in a lot of places that are endemic for malaria, especially in Sub-Saharan Africa, we're already at that optimal temperature most of the year.

(10:15): And any further warming is only making the climate less suitable for malaria transmission, not more suitable in many places like lowland tropical Africa. Now it's a completely different story in places that are in the highlands. Like in East Africa, there are some very tall mountains where it gets too cold for malaria transmission most of the time. And those are sort of the front lines for where climate change is driving expansions of malaria because it used to be too cold up high in the mountains and now it's getting just warm enough for optimal malaria transmission.

Russ Altman (10:45): So we know that species evolve. Are these mosquitoes sensing all of these changes? I guess, there's two ways they could respond and they could move, could move to areas where they like the temperature better or they could evolve and become optimal at 73 degrees or at 82 degrees. Are you seeing either or both of those?

Erin Mordecai (11:03): You're exactly right. Those are the two options that mosquitoes have. We assume that they're going to be able to move because mosquitoes are pretty good at following humans around, but we don't know for sure. Interestingly, malaria mosquitoes have been studied since right around the turn of the 20th century, so over 120 years. And yet we really don't know what their capacity is to adapt to climate warming. There have only been a few experiments that have measured mosquitoes, malaria transmitting mosquitoes at different temperatures.

(11:32): And of those, we haven't seen a study where people have looked at multiple populations. The key signature of adaptation to temperature would be that if the mosquitoes that come from really hot environments do better in hot environments and the mosquitoes that come from colder environments do better in colder environments. We actually just don't even know that. No one has done that experiment yet in the malaria transmitting mosquitoes. Now, my lab has recently done that experiment in some mosquitoes that are a little bit closer to home. Here in California we have the Western Treehole Mosquito, which is called Aedes sierrensis by its scientific name.

Russ Altman (12:04): I definitely should have saved that mosquito this morning. It was a huge mistake.

Erin Mordecai (12:08): It might've been that. Do you have any, so it breeds in these water-filled tree holes, which we have tons of this year in the Bay Area because of all this rain.

Russ Altman (12:15): Yes, we have a ton of those. We have a ton of those.

Erin Mordecai (12:17): Yes. So if you imagine a tree that has a little hole in it, maybe where a branch has fallen off, all this water will collect in the hole. If you look closely, it might have these little wriggling mosquito larvae in there. And what is really cool about this mosquito is that, well, cool if you like mosquitoes, is that it can occur all the way from San Diego into British Columbia and from the coast into the high Sierra. So it has a huge geographic range that spans a huge climatic gradient. So if there's any mosquito that's locally adapted to temperature, it's probably this one, right?

Russ Altman (12:48): Yes.

Erin Mordecai (12:49): So we collected hundreds of mosquito populations from across this huge range, ranging from San Diego to Seattle, and we brought these mosquito populations back to the lab. We reared them out. We weren't able to rear out all of these hundreds of colonies, but we were able to establish 10 different mosquito colonies from across this huge range.

(13:06): And we did an experiment to look at how the different traits that characterize their lifecycle respond to temperature, testing this hypothesis that the populations that come from warmer environments should have better performance at warm temperatures. And what we found was actually really surprisingly, most of their lifecycle had very little flexibility. So for the most part, all the populations performed the same across temperatures.

(13:30): In other words, they didn't have higher optimal temperatures or higher thermal limits if they came from warmer places. There was one trait, which is this very specific trait, it's called the pupil stage, which happens a few days before the mosquito emerges as an adult. And that particular trait did show evidence of thermal adaptation.

(13:49): So we saw about 1.6 degrees Celsius of variation across populations, and that variation was really strongly correlated with the temperature of the source environment. So the ones that came from a hotter location in their natural environment performed better at warm temperatures. This is about five times higher than the amount of thermal adaptation that's been measured for any terrestrial ectotherm in the past, meaning an organism, a cold-blooded organism that lives on land.

(14:15): So it is a pretty large amount of local thermal adaptation, and yet it's still not strong enough to overcome the amount of temperature variation that these mosquitoes already experience in their environment because they're already experiencing temperatures above their critical thermal maximum or the maximum temperature at which they can survive at all for multiple days a year.

(14:34): So it's sort of interesting because these mosquitoes seem to already have some sort of strategy that allows them to survive warm temperatures that based on the lab, they shouldn't really be able to survive. And there is some thermal adaptation across these populations, but it may not be enough to really allow them to adapt to future warming.

Russ Altman (14:51): So trying to think about this huge range and this robustness, I just want to ask a couple of things. First of all, these are all definitely this. I know the definition of species is tricky, but are these all kind of considered the same species or are we talking about, and do you think of them as subspecies?

(15:08): I guess, when you went to these 10 different places and got the flies, did you have an assumption that they could mate and they could cross mate and have offspring, or did they not do that? Because your findings as you're describing them, make me wonder, "Wait a minute, is this a very robust and flexible single species or has it specialized in these different climates?" And it sounds like from your results that there's only a little bit of evidence for specialization.

Erin Mordecai (15:33): That's a great question. Yeah. As far as we know, it's a single species. These are just different populations of the same species that could interbreed if they were mixed up together. We should probably do more genetics to confirm that for sure. But as far as we know, it is a single species. So it's kind of an amazing species. And it's also amazing that it doesn't have more standing thermal adaptation.

Russ Altman (15:54): Yes.

Erin Mordecai (15:54): [inaudible 00:15:55] this huge climate gradient.

Russ Altman (15:56): So I guess I have to ask, does this vector bring around diseases? Is this a disease vector, this mosquito that is-

Erin Mordecai (16:03): Good question.

Russ Altman (16:04): ... basically from San Diego to British Columbia?

Erin Mordecai (16:08): Luckily for us, it's not-

Russ Altman (16:09): Whew.

Erin Mordecai (16:09): ... a vector of human diseases. That's part of why we work with it in the lab because it's a little safer and easier to work with than these disease causing vectors.

Russ Altman (16:15): Better for the students.

Erin Mordecai (16:16): Yeah. It is potentially a vector of dog heartworm.

Russ Altman (16:20): Oh.

Erin Mordecai (16:20): It's one of the many vectors of dog heartworm. But other than that, it doesn't really transmit any human parasites at least not right now.

Russ Altman (16:27): Okay. All right, so great. So you've painted a really good picture of what's happening. And one other follow-up I wanted to ask about is in Africa where there are temperature changes, has any population seen a decrease in vector-borne, mosquito-borne disease because of high temperatures that just made it so non-optimal that they actually had measurable improvements in human health? Or is that too wishful of me to think of?

Erin Mordecai (16:53): It's a great question, and I'm also hoping that that's the case in a weird way. We do actually have some evidence that malaria declines in places with warmer temperatures. A colleague of mine, Dr. Desiree LaBeaud, has worked in Kenya for about 15 years studying mainly viruses that are transmitted by mosquitoes like Dengue and chikungunya.

(17:15): But in the process of studying these viruses, she's also studied a lot of malaria because you see a lot of malaria in these populations. And malaria has declined precipitously in Kenya over the last 15 years or so, in part because of successful control strategies, bed nets and indoor residual spraying. But it also shows this really clear temperature signature that is exactly what we predicted from models based on lab experiments. It's kind of amazing.

Russ Altman (17:40): That's awesome.

Erin Mordecai (17:41): If you go to places that are 25 degrees Celsius, which is the optimal temperature from malaria transmission, that's where you see the highest number of human cases, particularly in children. And if you go to places that are warmer than 25 degrees Celsius, malaria starts to decline really precipitously.

(17:57): So it does really suggest that this temperature relationship is real and it really does drive transmission dynamics. Of course, we've thought for a long time about the warming end where places become warm enough for malaria transmission and malaria begins to emerge. And that's important too. But it's also important to know that sometimes climate warming can actually drive certain diseases down.

Russ Altman (18:17): Right. Right.

Erin Mordecai (18:18): Now, there's an important sort of other side to this story that's not quite as positive, which is that malaria and the malaria transmitting mosquito have one of the cooler optimal temperatures at 25 degrees Celsius or 78 degrees Fahrenheit.

Russ Altman (18:34): Ah, darn.

Erin Mordecai (18:36): Dengue is transmitted by a completely different mosquito. Dengue, Zika, yellow fever, chikungunya, several different viruses are transmitted by what we call the yellow fever mosquito. And this mosquito has a warmer optimal temperature for transmission. Its optimal temperature is about 29 degrees Celsius, which I think is about 84 degrees Fahrenheit or so. So just as a lot places-

Russ Altman (18:57): That is bad news.

Erin Mordecai (18:58): ... are becoming too warm for malaria, they're becoming just right for Dengue transmission. So what we project is that with climate warming, we'll see much more of sub-Saharan Africa in particular becoming suitable for transmission of Dengue and other viruses by the yellow fever mosquito, even as the same places are becoming less suitable for malaria and the malaria mosquito.

Russ Altman (19:18): Fantastic. This is The Future of Everything with Russ Altman. More with Erin Mordecai next. Welcome back to The Future of Everything. I'm Russ Altman and I'm speaking with Professor Erin Mordecai from Stanford University. In the last segment, Erin told us about how mosquitoes are extremely sensitive to temperature, and that as temperatures change globally, the patterns of malaria disease are changing with it.

(19:42): In this segment, she'll tell us that it's not just about malaria, Dengue is also changing. And as the temperature increases, while the malaria may go down, the Dengue may go up. It's creating all kinds of challenges. But her group is helping because they're creating ways for policymakers to predict the impact of things like temperature change or even deforestation.

(20:05): She ends optimistic because communities are starting to be engaged and take control of their own fate by collaborating with scientists like Erin. So Erin, at the very end of the last segment, you said some intriguing things about the changing kind of, it was a good news, bad news, maybe the malaria mosquito is going down, but maybe the Dengue mosquito is coming up. Tell me more about that. Because Dengue is one of those diseases that a lot of people find very scary.

Erin Mordecai (20:30): Dengue is a scary disease. It's a really severe febrile illness. Often the first time you get Dengue, it causes fever and joint pain. It's no joke. You're definitely very sick, but it's actually the second or third time that you get Dengue that it can be even more severe because it has this interesting, these multiple serotypes that can sort of trick your immune system into overreacting if you've seen one serotype and then you get exposed to a new serotype.

(20:54): So for that reason, you can see really severe cases of Dengue that can lead to hemorrhage and even sometimes death. And Dengue has been explosively growing pretty much worldwide over the last couple decades. It's transmitted by what you call the Dengue mosquito, or it can sometimes be called the yellow fever mosquito because it's the same species of mosquito.

(21:12): And for reasons that aren't completely understood, we've seen this mosquito really roaring back in the last three decades or so, particularly in the Americas, Latin America, the Caribbean parts of the southeastern United States even. Historically, we had really successful vector control against this vector, but the methods that were used were pretty problematic and damaging.

(21:36): Often things like DDT or pouring oil into swamps and things like that that we don't really approve of doing so much anymore. And often these programs were really militarized in Latin America. So with the success of those programs, they were sort of victims of their own success and vector control subsided, the mosquito re-invaded and even invaded swaths of land that it wasn't present in before.

(22:02): And with that has come these serotype of Dengue, which have been really common and have circulated since World War II or earlier in much of Southeast Asia. So now Dengue is this global disease that's transmitted in Africa, in Asia, even in parts of Europe and North America as well as central and South America. And as I mentioned right before the break, the optimal temperature for Dengue transmission is about 84 degrees Fahrenheit.

(22:26): So it's pretty warm. So it is a tropical and subtropical disease, but places like Texas and Hawaii and Florida and other places in the United States have actually had local transmission of Dengue. So this is a disease where we're really concerned that the warming of the climate is going to expand transmission in addition to kind of the fact that humans are moving this mosquito around the world, and it does really well in urban environments because it can breed in containers. So it's very easy to get it established.

Russ Altman (22:53): And I know you've done some work modeling this phenomenon, so you can kind of help policymakers understand the real costs of some of these climate changes. Is that right?

Erin Mordecai (23:02): That's right. When policymakers think about mitigating climate warming, they think about what is the cost-effectiveness of different policies. And to determine the cost-effectiveness, you really have to know what the cost of climate warming is.

(23:14): And so far, a lot of these estimates include things like lost productivity, lost food production, consequences of heat waves, respiratory diseases, but they often don't factor in these infectious diseases and particularly mosquito borne diseases. So one of the things we're working on right now is using economic models to try to determine for every degree of warmer temperature, how many more Dengue cases will we see and where will those Dengue cases be distributed in the world. That's a number that if we can get-

Russ Altman (23:41): Wow.

Erin Mordecai (23:42): ... a pretty accurate estimate of that number, we can really start to inform policymakers that there is a huge social and health cost that also translates into a dollar cost of climate warming for people around the world.

Russ Altman (23:54): Do you collaborate with particular geographic areas on these projects, or are you trying to build a general model that could be used worldwide?

Erin Mordecai (24:02): In this particular case, we're trying to build a general model, but we do have a lot of collaborations in our work ranging from Peru to Ecuador to Brazil to Kenya. So these diseases are very important in lots of places of the globe, and it's really important to have that local perspective of how is a disease transmitted in a particular environment and what kinds of changes are going on that are causing these emergencies and resurgences of diseases like Dengue and Zika and chikungunya.

Russ Altman (24:28): Speaking about changes to the environment, I know one of the big things that you would look at is deforestation, and other big changes to geographic areas that may change their ecosystem wildly. Can you tell us about deforestation and how it affects the things that you care about?

Erin Mordecai (24:43): Yeah. Deforestation is a really big issue throughout the tropics, worldwide really. But right now, we're very concerned with deforestation in the tropics in places like the Amazon Rainforest, which is the world's largest remaining rainforest. It's a huge global carbon sink. So it's a very important place in terms of regulating the global climate. It's also very important culturally.

(25:04): There are hundreds of different indigenous groups that live in the Amazon, and it's very important biologically in terms of diversity as well. There's a huge diversity of course, of birds and insects and plants and all sorts of things in the Amazon Rainforest. And over the last few decades, we've seen increasing pressure for deforestation in the Amazon for things like growing subsistence crops or raising cattle for export.

(25:29): And these really come from external pressures. These are sort of people living in the Amazon trying to make a livelihood without many sustainable livelihood options. And so they're forced to turn to things like subsistence agriculture where it's slash and burn. You cut down the forest, burn up the trees, farm for a few years and then move on. And this kind of deforestation is really damaging to the forest, but it's also really damaging to the people that are forced to turn to that sort of livelihood.

(25:54): And the reason is that in the Amazon, malaria is transmitted by this slightly different mosquito species than the one that transmits malaria in Africa. The Amazon malaria mosquito is a forest edge specialist. So you imagine as you cut down the forest, you create this forest edge. That's where people are living and working, right on the forest edge, particularly in the frontier where they're doing subsistence farming, often living in pretty low quality housing.

(26:20): People are just trying to get by. They're just trying to make enough food to live off of. Living in the forest edge where this mosquito is breeding, and it's super attracted to people. So when you create that forest edge, you bring people to the forest edge, people get bitten by this malaria mosquito, and you see a huge rise in malaria cases.

(26:38): What some of our research has shown is that for every square kilometer of forest that you clear in the Amazon, it causes about 6.4 additional malaria cases. So if you scale that up to the level of deforestation that's happening every year, you can attribute tens of thousands of malaria cases to this deforestation.

Russ Altman (26:54): It's fascinating because that's the second time in this segment that you've mentioned how you can build a pretty simple mathematical model to help policymakers understand the financial and health consequences of these different practices.

Erin Mordecai (27:07): That's exactly right.

Russ Altman (27:09): Unbelievable. And so, yes, and it is, just to reflect a moment, it is diabolical of a mosquito to evolve so it's right at the edge of a forest.

Erin Mordecai (27:17): I know.

Russ Altman (27:18): Just at the time when these folks are cutting down trees. Well, in the last couple meetings, I want to-. Well, in the last couple of minutes, I wanted to ask you about solutions to these problems. You've laid out literally global challenges both, to health, and we didn't even get to the ticks. And I assume it's a similar but different story.

Erin Mordecai (27:40): Right.

Russ Altman (27:41): What are you optimistic about in terms of ways that we can go forward to try to address these challenges?

Erin Mordecai (27:47): It's hard to be optimistic really about these problems because they are so large and so global.

Russ Altman (27:51): I want to thank you for trying..

Erin Mordecai (27:53): But I will try. One of the things I'm optimistic about is the idea of community-engaged research, and that's sort of within the sort of Western research paradigm. That's kind of an emerging approach that people are increasingly starting to take, which is working with the local communities that experience these problems and often are victims of the problems themselves. It's often the case that people don't have access to sustainable livelihoods, they don't have good infrastructure, they don't have access to sort of formal housing and things like piped water, trash collection, and these are really huge issues.

(28:32): So one example of this type of research is I already mentioned my colleague, Dr. Desiree LaBeaud in the med school who works in Kenya quite a bit. And there she's learned that one of the big threats caused by Dengue is the fact that people don't have a way to get rid of all this plastic trash. There's all this cheap disposable plastic that's readily available, but there's no way to get rid of that plastic trash.

(28:54): And so it builds up in these informal dumps, which become breeding grounds for mosquitoes. And so what Desiree's work has done is really tried to work with the communities to understand this problem of trash. What would be the socially acceptable responses to this trash? How could we get rid of it in a way that provides livelihoods for people? Another example of this is an organization called Health in Harmony, which works with rainforest communities in Borneo, in Madagascar, and in Brazil, and does what they call radical listening.

(29:24): So they go and they really just listen to the communities and say, "What are the issues that you're facing?" Health, education, environment. What they find is that these communities have a long history of living in the rainforest in a sustainable way and are under pressure now to try to find ways to keep living in the rainforest and protecting it from outside interests that want to come and extract the resources.

(29:45): And often what the communities need is things like access to transportation to get to a health clinic or ways to market sustainable forest products that they can make, ways to create markets that they can live off of this without having to cut down large trees. And often the communities themselves are heartbroken by the deforestation that's taking place, and yet this deforestation is caused by the need to pay for healthcare.

(30:09): So groups like Health in Harmony are trying to figure out exactly at a very local level, what are the specific ways we can intervene? Is it building a shelter for the malaria biologists to live in when they come visit and test people? Or is it providing an airstrip so that the plane can come in and bring the healthcare providers? And it's these kinds of hyper-local interventions that can be really successful at both reducing deforestation and other types of environmental degradation and providing health and sustainability in these communities. So that's one of the things I'm super enthusiastic about and hoping to build up more collaborations with.

Russ Altman (30:44): No, I'm really glad you gave those stories because when you said community engagement and research, the first thing I thought is these poor folks have so many things on their mind that the research would be the last thing that you could ever get them interested in. But then you explained very clearly how this research is very kind of purpose-driven and actually winds up solving problems that they have. So that's fantastic.

Erin Mordecai (31:04): When this Health in Harmony group goes to these forest communities, they say, "What do you need as a gift from the rest of the world for the hard work that you're doing to protect the forest?" So the idea is not, "How do we fix this? How do we change your behavior?" It's like, "You are doing the thing that needs to be done, and how can the rest of the world give you a gift to support your ability to protect the forest?" And I think that's really the attitude we have to bring to this problem.

Russ Altman (31:29): Well, there you have it, and I want to thank you for ending on a true positive. Thanks to Erin Mordecai, that was The Future of Mosquito-Borne Diseases. You have been listening to The Future of Everything podcast with Russ Altman. If you're enjoying the podcast, please consider subscribing or following so that you can be alerted to every new episode and never be surprised by the future.

(31:50): Maybe tell your friends about it too. Definitely consider rating and reviewing it. That helps us grow, improve, and also spreads the word. We have more than 200 episodes in our back catalog, and so go back and check some of those. You can connect with me on Twitter at rbaltman and with Stanford Engineering at stanfordeng.