Ep 109 Chikungunya: Not dengue (or is it?)

It was soon, however, discovered that although a very painful it was by no means a dangerous disease, and that if the attack was rapid, the recovery was no less speedy. This, at least was the general belief until longer experience showed the troublesome nature of the secondary pains that constitute the third stage of the disorder. The most usual mode of attack was the following. A person in perfect health would suddenly feel a stiffness amounting almost to a pain in

one of his fingers, and frequently his little finger. The stiffness increased and was accompanied by an intense degree of pain, which spread rapidly over the whole hand and up the arm to the shoulder. The fingers of both hands in a few hours became swelled, stiff, and painful, preventing all attempts at bending the joints. This was followed in a short time by restlessness, depression of spirits, and a degree

of nausea, ending in some cases in vomiting. Then came on shivering, succeeded by fever, great heat of skin, intense headache, most acute pain in the back, knees, ankles, and in short in every joint. But perhaps the most distressing symptom of this stage was the intense pain in the eyeballs. In every case where the first stage was in any degree well marked, patients declared that they had never experienced, nor could have conceived, pains equal to what they felt

in this fever. Not one inch of the body from head to foot was exempt from suffering. An efflorescence was perceived at this time to begin at the palms of the hands and to spread over the whole body. After the aberuptive stage, the patient began to recover his spirits and his strength, but in many cases a complete want of taste remained for some days. Many people did not get rid of the pains in the joints for many weeks.

In general, however, the disease gave a degree of respite for three, four and even in some cases six weeks, and then attacked the joints with more pain and paralysis than at first. I conclude with the hope that I have done my duty in endeavoring to record a disease attended with so many curious symptoms, as justly to challenge the attention of every medical man, and particularly of those who are destined to practice in tropical countries. I love these old timey descriptions, Aaron so much.

equine encephalitis viruses. One thing I thought was interesting about alpha viruses in general is that at least one of the papers that I was reading was talking about how for a lot of alpha viruses, humans and our domestic animals are often considered dead end hosts, so we aren't necessarily like the evolutionary hosts for these pathogens, which is I think very interesting, especially because I'm going to end up comparing and contrasting chicken guna virus in this episode,

because it's compared a lot in the literature to a few other arboviruses like dengay zeca virus, yellow fever virus. All of those viruses are not in the alpha virus family. Those are all flaviaviruses, so a completely different family of viruses, some of which are very human specific like yellow fever or can cause disease in animals and humans kind of equally.

of Zeca virus, among many others. There are a lot of other species of eighties mosquitoes that can also transmit chicken gunya as well as perhaps some species of Culex that have been found to be infected, but predominantly, especially for humans, it's Albapictus and Agypti, and that's probably how I'll refer to them throughout this episode. And like many of our mosquito born viral and other pathogens, this life cycle can be a little bit complicated, but it goes

a little something like this. The mosquito takes the bite of an infected blood meal from an animal or a human in the case of chicken gunya, the virus has to travel through the guts of that mosquito, disseminate through the gut wall of the mosquito, travel through the hemolymph, and invade the salivary glands where they can replicate. And this process for chicken gunya virus within the mosquito takes

between two and five days to happen. Okay, So what that means is that the adult mosquito, after it takes its first blood meal, has to live at least two to five days to then be infectious to another person.

But what often happens is that they get interrupted really frequently during their feedings, so they don't get a whole blood meal at once, so they might bite and then bite, and then bite and then bite in order to get enough blood to be able to make an egg brood.

of cells. I'm going to pause in the life cycle here because i want to talk a little bit more about these two species of mosquito, even though we've already kind of like dove into some of the fun bits. These two species of mosquito, eighties albapictus and eighties agypti. We've talked about them a lot because we've done zeca, we've done yellow fever, we've done dengey. These mosquitoes are particularly good particularly well adapted to rural, urban, and human

built environments, especially eighties agypti. This is a mosquito that like just loves humans and our urban environments. These two mosquito species are generally both container breeding mosquitoes, so they do really well in things like old tires or that pot you forgot about that one pothole in your street that absolutely never drains your neighbor's pool that they drained three years ago but they never filled it, so there's

just like an inch of water in there. Also tree holes in more like suburban or rural environments, et cetera. Any tiny amount of standing water is enough for eighties and hype and Albapictus both to be able to breed

and survive. These two mosquitoes are also very aggressive. They're really aggressive biters, especially for humans, like they really like humans, and especially eighties Albapictus tend to be more diurnal than most mosquito species, so they can primarily bite during the daytime, in the mornings and in the evenings, so they're really difficult to avoid, and things like bednets that are often used to protect against other mosquito species that bite at

night don't do anything to prevent the bites of eighties albapictus and eighties agypty right, And like I said, they can complete their entire initial life cycle in as little as a week from egg all the way to adult. So in times of plenty in terms of rainfall, like the rainy season, you have many many broods of mosquitoes over and over hatching and going out in search of new blood meal. But at the same time, like many mosquito species, these eggs can dry out completely and then

survive until the next rainfall season. That's why they can do so well. In these small containers of water that might dry out completely, they can just hang on.

incredibly important source of vector born disease. But if that isn't enough, chicken gunya virus can also be spread via vertical transmission within the mosquito, meaning it can pass into the eggs and result in larvae and therefore adults that are already infected.

outbreak disease. The outbreak patterns in humans tend to be from human to vector to human transmission, so like humans being the primary reservoir, largely because these two species of mosquitoes do really like to bite humans. So I didn't get a sense of what the natural reservoirs likely are across the globe, but it probably varies in different parts of the world.

those from the eighteen hundreds. So love that the symptoms tend to start with a fever, of course, headache, back pain, very very severe joint pain and in potentially any joint ankles, wrist, fingers, hips, knees, large joints, small joints, and it does tend to be like so severe that it is difficult to bear. And people often will have like rigers and be bent over and just in an excruciating amount of pain. About fifty percent of people ish will also have some kind of

skin involvement. The most common rash is a very itchy, red splotchy kind of what I think of is just a very generic viral looking rash, so like little red splotches with bumps in the middle, what we call maculo popular. And this can be across the chest, the stomach, the back. I know the first hand account mentioned the palms, but I don't think that we tend to see that very commonly.

What's interesting is that in children the rash can often be quite different, with more of a blistering appearance, like very large blisters across the whole skin, or even with petikia, which are those tiny little purple spots that mean that you're having little, tiny pinpoint bleeds underneath your skin.

So it's thought to likely be something that's immune mediated, which is something that we see with other rboviral, viral and bacterial infections as well, and one of those things that we still just don't really understand.

in connective tissue formation. And so since this is a virus that has to infect our cells in order to replicate, these are the cell types, these fibroblasts and these muscle cells that they tend to infect and replicate in. There is some evidence from these again animal studies, that mice who lack T cells, especially certain subsets of T cells, have much less severe joint swelling and tissue damage as

a result of this viral infection. So it's thought that perhaps it's at least in part a T cell mediated response that causes all of this joint pain and inflammation in those spaces, because that's where the virus is actually infecting.

of inflammation that then cause a lot of pain. Okay. The difference in gout, of course, is that we know exactly what those particular drivers are. See our gout episode.

than one percent. It was thought, especially historically, to be very very rare to die from chicken gunya, although with more recent outbreaks we have seen an increase in mortality, especially in the very old, the very young, or the otherwise immunal compromised, so that less than one percent is probably an underestimate, but it certainly historically has been much less virulent than dangay fever, which if it causes dang gay shock syndrome, has a mortality rate of twenty percent

or more or yellow fever which has a case fatality rate between ten and fifty percent, or my marsh. Yeah, so when you compare those, then yes, chicken gunya seems relatively benign. But months or years of debilitating joint pain can cause disability. It can cause inability to work, which might mean inability to feature family. So it does have really serious consequences. So I want to emphasize that it's not a benign illness by any means.

severe and have resulted in neonatal deaths. Okay, when it comes to whether or not you can have an asymptomatic infection, which is something that we talk a lot about, especially in viral diseases or mosquito born diseases, I don't know who to believe in terms of how many asymptomatic cases. There are a lot of papers that I read. I would say the majority estimate that it's actually very rare to have an asymptomatic infection, which is quite different than something like dangay or zica.

sids like ibuprofen. And the reason for that is because clinically, during outbreaks, both because the symptoms can be very nonspecific in the acute phase, they can overlap a lot, and these two viruses tend to occur in the same areas, and chicken gunya virus can be difficult to tell apart, and enzids can be very dangerous in Dangay because it can lead to bleeding, right, okay, yeah, And so for that reason, it's like, if you're not sure, just tie it all.

just talked about all the similarities. But for our listeners too, not just the biology or the transmission or the epidemiology of these viruses will sound similar, but also a bit

of the history. I think, Okay, we'll sound a little bit echoes of each other, all mosquito born viruses, all on the rise, all recently attracting more attention and generating more headlines than historically they used to due to their recent geographics, spread into new regions, especially regions like Europe and North America, where the disease has changed from being an over there disease to a weight it's here now one.

And with dangay and chicken gunya especially, the similarities extend beyond epidemiology and disease ecology and down into the clinical side of things, since they can cause a lot of the same symptoms, as well as their histories, which, as I'll talk about, have blended together and are kind of in the process of being rewritten.

let's take a closer look, but I do. In researching for this, it struck me that these arboviruses are often kind of lumped together and talked about as a single entity. And I feel like it's just as important to remember what differences among these infections can tell us as it is to ask what their similarities can say about these diseases. Yeah, and I think that throughout this episode we'll have the

opportunity to do both. But first things first, Aaron, you asked, as you always do, where this virus came from, And it's a great question that I'm only going to be able to answer in part. Okay, most papers I read for this episode, if they mentioned the evolutionary origin of chicken gunyavirus at all, it was just to say that

it wasn't clear when or where this virus emerged. Right, of course, one paper gave a not super narrow estimate that the ancestor of chicken gunyavirus emerged fairly recently, maybe as recently as eighteen fifty or as far back as the year six fifty CE. It's like, which, like in the scheme of things, is not a big range, but it does seem like a big range.

pronounce it, but that's transmitted by anophilies mosquitoes. As humans began to settle in larger groups and especially began to store water, even you didn't even have to store that much of it, that provided opportunities for the evolution of the more domestic eighties agypdi agypdi mosquito subspecies which hung around these settlements, and a loud for human to human transmission of chicken gunya. So it's maintained and just humans

and mosquitoes. And that's in contrast, of course, to the spillover into humans from the enzootic cycle when a bridge vector species of mosquito, one that feeds on both humans and non human primates or other vertebrate reservoirs, bites a human and transmits the virus.

cause this big outbreak yep. And so these big outbreaks would happen from time to time, and it fed initially by the spillover, and then it would just sweep through the population until most people became immune, and then the virus would go quiet for a while. And this is essentially how the cycle would have continued for hundreds of years until its discovery in nineteen fifty two. In July of that year, a seemingly new disease began popping up

in the Makondai Plateaus region in Tanzania. Within two or three weeks of the first case appearing in a village, sixty to eighty percent of the population became infected. Whoa, with some households reporting a one hundred percent infection rate.

found to modify the pain. Yeah. No one in the region could remember a similar epidemic ever occurring there, and so this disease was given a new name from the Macondai dialect chicken gunya, meaning that which bends up or I've also seen it as the disease that bends up the joints. No one who had the disease got it a second time. Wow, And people said you either definitely had it or you definitely did not. There was just no in between.

because dang gay is like clinically quite sabers. Yeah, studies were carried out where researchers collected blood feeding arthropods from all around the villages where the outbreak occurred, and sure enough, all signs pointed to eighties EGYPDI. Because of the clinical similarity to dan gay, people figured that when they found the virus, it was just going to be like a new subtype or a new strain of the Danae virus.

But analysis of serum samples collected showed that it seemed to be a new kind of virus, not a Danae virus, And so it got to keep the name that it got during this first outbreak, Chicken Gunya. And maybe it's because we've done so many episodes where the story goes something like the disease was first recognized into ancient times and people wrote about them for hundreds of years, but no one knew what caused it or how it was

transmitted until recently. But I just think it's so amazing that within a few years of its first appearance, we had a name, we had a clinical picture. We had a vector and a causative agent for this new disease. Yeah, I mean, and it shows how far we'd come by

the nineteen fifties in terms of microbiology. If you cast your mind back to our Dangaye episode, you may remember that the first epidemics of dangay were described in the late seventeen hundreds, and it took another one hundred years and then some before it was linked to mosquitoes, and decades after that before the virus was identified and like classified. And here we are with chicken gunya, learning all that and more about this brand new disease in just a

few years. It's amazing, or is it now?

knowledge about the seemingly new disease so quickly. Yeah, totally, But I did want to take some time to revisit the early history of dangay and see if maybe what people thought was dangay was actually chicken gunya. And this isn't something that I like came up with on my own. There are lots of papers that have been looking into this possibility for you know, decades, and they've come up

with some pretty convincing evidence. All right. So a nineteen seventy one paper by Donald Carey titled Chicken Gunya and Dngay a Case of Mistaken Identity takes a closer look at many so called dengae epidemics since the eighteenth century and uses clinical descriptions from eyewitnesses to see whether it

seems more in line with dengae or chicken gunya. Because although the two diseases do bear many similarities and can be quite varied in terms of symptom presentation, there do seem to be some distinguishing features between the two, like one of them is this lingering long, lingering joint pain in chicken gunya and also just the fact that dengey has a much higher mortality rate, And so these differences would be a lot more easily seen in outbreaks and

epidemics when you can look at a whole bunch of people and see patterns emerge, rather than looking at two people side by side that like, both have kind of a rash, both have headache, joint paine and fever.

if both are happening simultaneously, which can absolutely happen. Yeah, So it is really interesting to be able to take a step back and look at things historically, because there are patterns that emerge when you're able to look not at an individual person but at a population yep.

knuckle quarts or knuckle joint fever. In present day Karta, and the description written by David Bylon does suggest who was witness at the time does suggest Chicken Gunya. Quote. I noticed a gnawing pain in my right hand and in the joints of the hand and arm, which gradually increased, extending to the shoulder and then over my whole body, so that at nine o'clock that evening I was in

bed with a high fever. I had a restless and sleepless night, suffering severe pains over the entire body, especially in the legs and arms, and in the joints. This is a brief notice concerning a very well known disease, which, however, in the memory of man here in Batavia, has never reached an epidemic, and which has therefore seemed wondrous to the inhabitants. Around this time, an outbreak of a similar disease was happening in Cairo. This one known as quote

the knee trouble. It threw all the people into a fever. Its first attack lasted for three days, after which the illness increased or diminished, acording to the disposition of the individual. It was accompanied by pain in the joints, knees, and extremities as well as inability to move, and often with swelling of the fingers. The after pains lasted more than a month. The onset was sudden, the body being broken by it, and the head and knees taken hold of.

So the descriptions of this disease painted this excruciatingly painful picture, but not really a deadly one. And that was something that's in sharp contrast to what Benjamin Rush saw during a seventeen eighty epidemic in Philadelphia of a disease that he nicknamed breakbone fever. This is often considered to be the first description of Danngay fever. And I actually had this passage in my day notes, and I don't think I read it in the episode, so I'm just going

to read you a snippet of it here. And also, this is like a very full of quotation section, but I feel like it's important because we're going through historical outbreaks. Okay. Quote. The fever generally came on with rigor, but seldom with a regular chili fit. When the fever did not terminate on the third or fourth day, it frequently ran onto

the eleventh, fourteenth, and even twentieth days. In some cases, the discharge of a few spoonsful of blood from the nose accompanied a solution of the fever, while in others a profuse hemorrhage from the nose, mouth, and bowels on the tenth and eleventh days preceded a fatal issue of the disease. The pains which accompanied this fever were exquisitely

severe in the head, back, and limbs. The disease was sometimes believed to be a rheumatism, but its more general name among all classes of people was the breakbone fever.

Russia's description, which also mentions a rash and burning in the palms of the hands and soles of the feet, it does have some echoes of chicken gunya like are There are lots of similarities between these descriptions that I've read so far, But it's also much deadlier, Like he's talking about hemorrhaging, he's talking about people dying and how often it happens, And that didn't seem to happen in the descriptions at least from the seventeen seventy nine Jakarta epidemic,

as well as the series of outbreaks of a similar disease that occurred in India. And the West Indies in the eighteen twenties, which, like in Jakarta, had a super high attack rate but a low mortality rate. In eighteen twenty four to eighteen twenty five, an epidemic of Kiddinga peppo began in East Africa and spread to India, where it caused huge outbreaks, with one contemporary observer estimating that

ninety five percent of the population of one region was affected. Wow. Yeah, And although this has historically been chalked up to denge, more recently it's been suggested to have been chicken gunya. And that's in large part due to the emphasis on the sudden onset an extremely fast onset and lingering joint pain quote a protracted debility and long continued pains and the ankles and dull aching in the joints of the fingers and toes for many weeks after the cessation of

the fever. The outbreak, which also had high prevalence and low mortality, that occurred in the West Indies a few years later, around eighteen twenty seven, eighteen twenty eight. So that was a description from our first hand account, and that's what led to the nickname Dandy fever.

have dang gay shocked, dang gae hemorrhagic fever, and severe infections. So, especially in an initial infection and in that acute phase. I do think that chicken gunya and dan gay can be very hard to tell apart for sure.

breakbone fever or the billious remittant fever. I think that the diseases, though somewhat alike in a few symptoms, are essentially different. Four circumstances chiefly distinguished the fever that I have described. First the suddenness and peculiarity in its mode of attack. Secondly, the well marked distinction between different stages. Thirdly, the peculiar eruption. Fourthly, the peculiar nature and duration of

the after pains. So dangay and breakbone fever were not always used synonymously, and in fact, for many doctors for a time, they seemed to be written about as similar but distinct diseases, with breakbone fever being this more deadly and debilitating disease and one that you could become reinfected with or like you could be susceptible to multiple attacks.

It's like how it was talked about and what they call dangay was milder except for the long period of lingering joint pain, and it was a one time only disease.

was also transmitted by mosquitoes. And I feel like I'm not doing a very good job of this, but like, when I'm talking about dangay and these historic outbreaks, I really should be putting quotes around dan gay, so like what they were calling kay, right, And so when these researchers decided, like, hey, okay, let's see if we can link mosquitoes to this, there was an outbreak of quote dangay that was going on in Lebanon, in Australia and

in the Philippines. And these outbreaks provided the perfect opportunity to test this out, this mosquito hypothesis using human quote unquote volunteers. Researchers successfully demonstrated that the disease was caused by a virus and transmitted that virus from sick people to healthy people through the bite of an infected eighties Egypti.

But it just so happens that the virus that was endemic in these study sites in this outbreak of quote dangay was not the chicken guna virus, but the dangae virus. And so it was assumed that this and all preceding historical epidemics that were went under the name dangay were

caused by this virus alone. And the reason I say coincidence, maybe that's like not really the right, We're just a matter of like happenstance, I guess is because if these researchers had instead been working on an outbreak of quote dengay that was actually caused by chicken gunya virus, right,

dangay would mean something different than it does today. It would mean that chicken gunya virus or what we call the chicken gunya virus and the virus that we called dangay today would probably have a different name.

constantly evolving. Yeah, whether through the discovery of old texts that you know, put it in a new place, or bring it back even farther, or through molecular tools tracing the actual evolution of a pathogen or a vector, or because modern events add to the story. The history of chicken gunya that somebody tells in ten years probably isn't going to sound the same as this one, the one

that you know we're telling now. And the second reason is that I think this highlights both the benefits of using historical descriptions of disease, because they allow you to retrace the steps of its spread and how our understanding grew,

but it also highlights the drawbacks. It certainly seems likely that chicken gunya has been more widely distributed for longer than we initially thought, given some of these historical descriptions being like pretty on the money about chicken gunya, and also the fact that its vector eighties a jip die or one of its vectors was present in a lot of these places, which would have made transmission feasible possible.

But we can't know for sure. We can't know whether the author of an account was highlighting an unusual case or a typical one, whether they were interested in a certain set of symptoms, so they played those up while ignoring others, whether there was some reason that they were like invested in making a difference between dangay and breakbone

fever and really like highlighting those differences. These are also similar viruses with a substantial overlap in disease symptoms and geographic range, And it's possible that one outbreak of dangay was actually caused by dangae virus while another was caused by chicken gunya virus. Maybe another was caused by yang

yong virus or a different virus entirely. But in any case, these historical accounts aren't just useful for historians, but like you talked about, Aaron, also for modern day researchers looking for clues into a disease's ecology and epidemiology. What do we see on a big scale, What are the things that stand out historically and why? But speaking of modern day researchers, let's head back to the twentieth century to see what happened with chicken gunya once it was formally

identified in the nineteen fifties. So as you might expect, having a name, a vector, and a virus made it easier for people to recognize subsequent outbreaks which occurred throughout the nineteen sixties and beyond in Sub Saharan Africa. Chicken gunya was first detected outside of Africa in nineteen fifty eight in Thailand, and over the next few years the virus continued. It spread throughout Asia into Cambodia and India,

although it was probably not its first rodeo there. Yes, antibodies against chicken gunya were found in serum collected from people in India in the early nineteen fifties. And you already heard this whole spiel that I just gave about mistaken identity between chicken gunya and danngaey. But what was happening in the nineteen fifties, the nineteen sixties into the nineteen seventies is that the scale of these epidemics seemed to be growing, with one epidemic in Chennai, India in

nineteen sixty four causing over four hundred thousand cases. But chicken unyon didn't maintain this huge growth because after the nineteen seventies things seemed to like cool down a bit, possibly thanks to a high rate of immunity from previous epidemics. It seems like unclear but researchers have pointed to a possible cyclical nature of chicken gunya outbreaks, which I think is interesting. But then in two thousand and four, everything changed yep, or rather an amino acid in the virus changed.

So it's been hypothesized and I think pretty well supported from experimental research that this change of this amino acid resulted in this viral lineage of the chicken gunya virus being able to be more easily transmitted by eighties Albalpictus, a mosquito species that previous to this had not really been implicated as a major vector. It was like eighties A Jypti for the urban human to human cycle, and then other eighties species for the enzootic cycle. But now

suddenly there's this new Albapictus species in play. And the result of that was that chicken gunya exploded in two thousand and four from eastern Kenya into islands in the Indian Ocean, involving hundreds of thousands of peapleople and attack rates as high as thirty five percent or even sixty

three percent I saw on one island. Over the next years, chicken gunya grew to be a major public health problem, causing massive outbreaks in South and Southeast Asia involving millions of people, where for the first time these neurological and other complications of the infection were observed. And with eighties Albapictus now as this major vector, its potential for global spread grew tremendously because Albopictus also extends further than eighties

Egypti into temperate regions. It's a great urban mosquito that overwinters really well. Like you talked about Aaron loves feeding on humans, has these desiccation resistant eggs. I mean, we're up against quite a lot in terms of chicken gunya control, and I do have a little asterisk there in terms of like genotype by genotype interactions between Albalpictus and the virus, so like some combo don't do as well as others.

But I mean it's complicated but still ye, And it gets even more complicated when you add urbanization and climate change to the mix, as you have to do when you talk about disease or vector born diseases. But yeah, I mean this is kind of like a rapid wrap up.

But I think that what I took away from this is that we have a lot to learn about the future of chicken gunya, and it seems quite daunting, but I think looking at the past, and even like the very recent past, chicken gunya can serve as yet another lesson along with dange, along with SIKA, along with other arboviruses, on just how easily mosquito born viruses or other pathogens

can reach global distributions. But also it's an important reminder that we have to consider their individual ecologies and pathology in predicting future risk, like for instance, dangae's multiple circulating serotypes or chicken Gunya's increased transmission via albul pictus. It's all very messy and it's all very complicated, but it's so important with that. Aaron, can you tell me what's going on with chicken gunya today?

the town next door. So let's talk a little bit about the numbers that we do have and that we have seen and what chicken Gunya has been doing globally, shall we, Like you mentioned Aaron starting in two thousand and four, an outbreak in Kenya spread throughout the Indian Ocean and persisted for several years. This kind of one big outbreak. It spread to Lari, Union Island, where more than a third of the entire population became infected. It spread to India, where cases reached more than one point

five million people by two thousand and six. By two thousand and seven, it continued. It's spread and octophenous one of my favorite words.

By twenty thirteen. If we jump ahead, twenty thirteen is when we see chicking gunya spread to the Americas for the first time. In twenty thirteen, it was across Caribbean islands, where cases reached tens of thousands in a matter of months, and then rapidly spread to the South American, Central American North American continent, with twenty fourteen having over one million

suspected cases reported to the Pan American Health Organization. Now, these cases, these strains do not have that albapictus gene and are spread primarily by eighties Egypti. So we've got them both all over the world.

on this podcast. These are imperfect measures, but they are one way to get a sense of the impact and burden of disease, and I think, in the case of chicken gunya, a really good way to do it, because we're not necessarily going to see a lot of death or mortality from chicken gunya, but we are going to see a lot of years of healthy life lost as the result of this disease, and that's what the disability

adjusted life years are measuring. So in the case of chicken gunya, these researchers estimated a global annual burden looking at data from twenty ten to twenty nineteen of one hundred and six thousand disability adjusted life years.

be worried about. Both of these mosquito species are very well suited for urban environments, so there are a lot of papers that have looked specifically at the effects of rapid urbanization on mosquito density and distribution. And the long and short of it is that it's terrifying news in terms of mosquito born disease, not just chicken gunya, but

including chicken gunya. Because these papers tend to conclude that urbanization across the globe, not localized to one particular part of the world, correlates with a higher risk and abundance of these eighties mosquitoes. You have an increase in favorable breeding grounds. You have higher larval development rates in urban areas compared to natural areas. You have potential for greater

adult survival time. And all of these things mean that you have a potential for greater vector competence, that these vectors are living longer and therefore transmitting or at least having the potential to transmit disease more readily.

I guess I didn't mean for this to be like such a bummer of an ending but I feel like that's an important part. Like arboviral diseases like chicken gunya have been popping up throughout human history always, they have been here with us, and I think that many of us probably remember when chicken gunya was making a ton of headlines in twenty thirteen and twenty fourteen because we had cases in Texas and in Florida, and then it went away and we forgot about it, except that it

didn't go away. And these viruses, these diseases are not going away, and it takes a huge effort of like multidisciplinary public health work to be able to understand these risks and potentially reduce them.

spread disease. I don't have a final answer because I just didn't have time to dig into it, but there does seem to be at least some evidence that some wobakia, if introduced two ads mosquitoes, might decrease the transmission of chicken gunya.

mRNA vaccine candidates, there's live attenuated vaccine candidates. There are measles vector vaccine candidates, and viral particle vaccine candidates. But we don't have any that I could tell. We're particularly close to licensure at this point. Okay, Yeah, but the potential exists, and there's people working on it. I have a feeling it's largely down too funding.

it spread since nineteen fifty two. And then for the discussion of dangay versus chicken gunya and all of that, there's that paper by Donald Kerrey from nineteen seventy one called Chicken Gunya and Dangay a Case of Mistaken identity.

the diseases they transmit a systemic review. So I definitely have that one too. It's a good one. It's terri fun.