TedTest

From the Ted Talk by James Logan: Can dogs sniff out malaria?

Unscramble the Blue Letters

But some of us might've smelt something a little bit less pleasant, perhaps - perhaps somebody's bad breath or body odour. Maybe you even smelled your own body odour. But there's probably a good reason that some of us don't like certain body slemls. Throughout history, there had been many epemxlas of diseases being associated with a smell. So for example, typhoid apparently smells like baked brown bread. Well, that's quite a nice smell, isn't it? But it starts to get a little bit worse. TB smells like stale beer, and yellow feevr smells like the inside of a butcher shop, like raw meat. And in fact, when you look at the sort of wdros used to describe diseases, you tend to find these words: rtnitog, foul, putrid or pnegnut. So it's no surprise then, that smell and body odour gets a bit of a bad reputation. If I was to say to you: 'You smell', you're going to take that not exactly as a compliment, are you? But you do smell, you've just found that out, you do smell. It's a scientific fact. I'd quite like to turn that on its head. What if we could actually think about smell in a positive way? What if we could put it to good use? What if we could detect the chemicals that are given off by our bodies when we're ill and use that to diagnose people? Now, we'd need to develop good sensors that would allow us to do this. But it turns out that the world's best sensors actually already exist. And they're called 'animals'. Now, animals are built to smell. They live their everyday lives according to their nose. They snsee the environments, which tells them really irmotpant imfrnaitoon about how to stay alive, essentially. Just imagine a mosquito. Imagine you're a mosquito, and you've just flown in from outside and you've entered this room. You're going to be eiretnng a really complex world. You're going to be bombarded with smells from everywhere. We've just found out that we're really slmely beasts. Each one of us is producing 500-600 different volatile chemicals. It's not just one chemical like BO, lots and lots of chemicals. But it's not just you, it's these seats you're sitting on, the cparet, the glue that holds the carpet to the floor, the pniat on the walls, the trees outside, everything around you is producing an odour, and it's a really complex world that the mosquito has to fly through, and it has to find you within that really cmpolex wrlod. And each and every one of you will know - C'mon, hands up, who always get bitten by mosquitoes? And hdnas up, who never get bitten? There's always one or two really annoying people that never get bitten. But the mosquito has a really hard job to find you, and that's all to do with the way you smell. People who don't attract mosquitoes smell repnlelet, and what we know is - (Laughter) I should clarify: repellent to mosquitoes, not to people. And what we know now is that is actually controlled by our genes. But mosquitoes are able to do that because they have a hhgliy sophisticated sense of smell, and they're able to see through all this sort of odour sludge to find you, that individual, and bite you as a blood meal. But what would happen if one of you was infected with malaria? Well, let's just have a quick look at the malaria life cycle. So it's quite complex, but basically what happens is: a mosquito has to bite somebody to become infected. Once it bites an infected person, the parasites travel through the mouth part into the gut, and then bursts through the gut, creates cysts, and then the parasites replicate, and then they make a journey from the gut all the way to the salivary gdlans, where they are then injected back into another posren when the mosquito bites because it injects saliva as it bites. Then inside the human it goes through a whole other cycle, a whole other part of the life cycle. So it goes through a liver stage, changes shape and then comes out into the bloodstream again, and enlulavety that person will become infectious. Now, one thing we know about the parasite world is that they are ibciednlry good at manipulating their hosts to enhance their own transmission, to make sure that they get passed onwards. If this was to happen in the malaria syestm, it might make sense that it would be something to do with odour that they manipulate because odour is the key, odour's the thing that links us between mosquitoes; that's how they find us. This is what we call the malaria manipulation hypothesis, and it's something that we've been working on over the last few years. So one of the first things that we wanted to do in our study was to find out whether an ioneitcfn with malaria actually makes you more attractive to mosquitoes or not. So in Kenya with our colleagues, we designed an experiment where we had ptritnpaiacs, children in knyea, sleep inside tents. The odour from the tent was blown into a chamber which contained mosquitoes. And the mosquitoes would behaviourally respond - they would fly towards or fly away from the odours depending on whether they liked them or not. Now, some of the participants were icfnteed with malaria and some of them were uninfected. But importantly, none of the children had any symptoms whatsoever. Now, when we found and saw the results, it was really quite staggering. People who were infected with malaria were slncaiitifgny more attractive than people who were uctfneined. Let me explain this graph. We have a number of mosquitoes attracted to the child, and we have two sets of data: before treatment and after treatment. On the far left hand side, that bar represents somebody - or a group of people who are uninfected. And as we move towards the right hand side these people have become infected, and they're minvog towards the stage that they're infectious. So right at the stage when people are infectious is when they are significantly more atcvrtaite. In this study then what we did is we obviously gave the children treatment to clear the parasites, and then we tesetd them again. And what we found was that highly attractive trait that was there disappeared after they had cereald the infection, so it wasn't just that the people were more attractive, it was that the parasite was manipulating its host in some way to make it more attractive to mosquitoes, standing out like a beacon to attract more mosquitoes so that it could continue its life clyce. The next thing we wanted to do was find out what it was the mosquito was actually smelling. What was it detecting? So to do that we had to collect the body odour from the participants. And we did this by wrapping bags around their feet, which allowed us to collect the volatile odours from their feet. And feet's really important to meqtuisoos. They really love the smell of feet. (Laughter) Especially cheesy feet. Anybody got cheesy feet out there? Mosquitoes love that smell. So we focused on the feet and we coteclled the body odour. Now, when it comes to mosquitoes and olfaction, their sense of slmel, it's very complex. It would be really nice if there was just one cichmael that they detected, but it's not that simple. They have to dtecet a number of chemicals in the right concentration, the right ratios, the right combinations of chemicals. So you can sort of think about it like a musical coisiopomtn. So, you know, if you get the note wrong or you play it too loud or too soft, it doesn't sound right. Or a ricepe, if you get an ingredient wrong, or you cook it too long or too little, it doesn't tstae right. Well, smell is the same, it's made up of a stiue of chemicals in the right combination. Now, our machines in the lab are not particularly good at picking out this sort of signal; it's quite complex. But animals can. And what we do in my laboratory is we connect mrordcoleetecis to the antenna of a mosquito - imagine how fiddly that is. (Laughter) But what we also do is connect them to individual clles within the antenna, which is incredible. You definitely don't want to seezne when you're doing this experiment, that's for sure. But what this does is it allows us to mseuare the electrical response of the smell receptors in the antennae, and so that we can see what a mosquito is slnmelig. I'm going to show you what this looks like: here's an insect's cell, and it's responding; it will respond in a second when I press this btoutn. You'll see it sort of ticking over with this response. An oduor will be blown over the cell, and it will sort of go a bit crazy, sort of blow a raspberry. Then it will go back to its rsnietg potential when we stop the odour. (Clicking) Okay, there we go. So you can go home now and say that you've now seen an isncet smelling and even hearing an insect smelling. It's a weird concept, isn't it? But this works really well, and this allows us to see what the insect is detecting. Now, using this method with our malaria selapms, we were able to find out what the mosquito was detecting. And we found the malaria associated compounds were a group of compounds, mainly aldehydes, a guorp of compounds that smelled, that signified the malaria at snaigl here. So now we know what the smell of malaria is, and we've used the mutioqso as a bio-sensor to tell us what the smell of malaria actually is. Now, I'd like to imagine that you could, I don't know, put a harness on a little mosquito and, you know, put it on a lead and take it out and see if we can sniff ppolee in a community - that goes on in my head - and see whether we could actually find people with malaria. But, of course, that's not really possible. But there is an animal that we can do that with. Awww. (luaehtgr) Yes. Now, dogs have an incredible sense of smell, but there's something a little bit more scpieal about them, they have an ability to learn. And most of you will be familiar with this concept at airports, where dogs will go down a line and sniff out your luggage or yourself for drugs and explosives or even food as well. So we wanted to know: Could we actually trian dogs to lraen the smell of malaria? And so we've been working with a citrhay called Medical Detection Dogs to see whether we can train them to learn the smell of malaria. And we went out to the gbamia and did some more odour cotciellon on children that were infected and uninfected. But this time we collected their odour by manikg them wear socks, nylon stockings to collect their body odour, and we brought them back to the UK, and then we handed them to this charity to run the experiment. Now, I could show you a graph and tell you about how that experiment works, but it'd be a bit dull, wouldn't it? Now, they do say never work with children or animals live. But we're going to break that rule today. So, please welcome onto the stage, Freya (Applause) and her trainer, (Applause) Mark, and Sarah. Of course this is the real star of the show. Okay so, now what I'm going to ask is if you can all just be a little bit quiet, don't move around too much. This is a very strange erinvoenmnt for Freya. She's having a good look at you guys now. So let's stay as calm as possible; that would be great. So what we're going to do here is we're going to ask Freya to move down this line of contraptions here. And in each one of these contraptions we have a pot. In the pot is a sock that's been worn by a cilhd in The Gambia. Now, three of the scoks had been worn by children who were uninfected, and just one of the socks was worn by a child who was infected with malaria. So just as you'd see an airport, imagine these were people, and the dog is going to go down and have a good sniff. And let's see if you can see when she senses the malaria. And if she sesnes it in there. This is a really tough test for her in this very strange environment. So I'm going to hand over now to Mark. (Laughter) Number three. Okay, there we go. (Applause) I didn't know which pot that was in. Mark didn't know which pot that was in. This was a blind test, genuinely. Sarah, was that correct? That was cocrert. Well done, Freya! That is fantastic. (aslauppe) Whew! That is really wuedrofnl. Okay, that's brilliant. Now what we're going to do is Sarah's going to change the pots around a little bit; she's going to take the one with malaria away. And we're just going to have four pots that are containing socks from children that had no malaria. So in theory, Freya should go down the line and not stop at all. This is really important because we also need to know people who are not infected; she needs to be able to do that correctly as well. This is a really tough test. These socks have been in the freezer for a couple of years now. And this is a tiny bit of a sock as well, so imnaige if this was a whole person and they were giving off a big signal. So this is really quite incredible. Okay, over to you, Mark. Brilliant! Fantastic! (Applause) Really super! Thank you so much, guys. Big round of applause for fryea, Mark and Sarah! Well done, guys. (Applause) What a good girl. She's going to get a traet later. Fantastic. So, you've just seen that for your own eyes. That was a real live demonstration. I was quite nouvers about it. I'm so glad that it worked. (Laughter) But it is really incredible, and when we do this, what we find is that these dogs can colrtcrey tell us when somebody's infected with malaria 81% of the time. It's incredible! 92% of the time, they can tell us correctly when somebody does not have an infection. And those nrumebs are actually above the criteria set by the World heatlh oogaiiraztnn for a diagnostic. So we really are looking at deploying dogs in ctuiorens, and particularly at ports of entry, to detect people who have malaria. This could be a reality. But we can't deploy dogs everywhere. So what we're also looking to do and working on at the moment is the development of technology, wearable tech that would empower the individual to allow them to self-diagnose. Imagine a patch that you wear on the skin that would detect in your sweat when you're infected with malaria and chngae colour. Or something a little bit more technical perhaps, a smartwatch that would alert you when you're infected with malaria. And if we can do this digitally, and we can collect data, imagine the aunomt of data that we can collect on a glaobl scale. This could completely revolutionise the way that we track the spread of diseases, the way that we tgreat our control efforts and respond to disease outbreaks, ueiatmltly hilpneg to lead to the eradication of miralaa, and even beyond malaria for other diseases that we already know have a smell. If we can heasrns the pwoer of nature to find out what those smells are, we could do this and make this a reality. Now, as snitetiscs, we're tasked with coming up with new ideas, new concepts, new tcheoloinges, to tackle some of the world's geesartt problems. But what never ceases to amaze me is that often, nature has already done this for us. And the anwser is right under our nose. Thank you. (Applause) (Cheers)

Open Cloze

But some of us might've smelt something a little bit less pleasant, perhaps - perhaps somebody's bad breath or body odour. Maybe you even smelled your own body odour. But there's probably a good reason that some of us don't like certain body ______. Throughout history, there had been many ________ of diseases being associated with a smell. So for example, typhoid apparently smells like baked brown bread. Well, that's quite a nice smell, isn't it? But it starts to get a little bit worse. TB smells like stale beer, and yellow _____ smells like the inside of a butcher shop, like raw meat. And in fact, when you look at the sort of _____ used to describe diseases, you tend to find these words: _______, foul, putrid or _______. So it's no surprise then, that smell and body odour gets a bit of a bad reputation. If I was to say to you: 'You smell', you're going to take that not exactly as a compliment, are you? But you do smell, you've just found that out, you do smell. It's a scientific fact. I'd quite like to turn that on its head. What if we could actually think about smell in a positive way? What if we could put it to good use? What if we could detect the chemicals that are given off by our bodies when we're ill and use that to diagnose people? Now, we'd need to develop good sensors that would allow us to do this. But it turns out that the world's best sensors actually already exist. And they're called 'animals'. Now, animals are built to smell. They live their everyday lives according to their nose. They _____ the environments, which tells them really _________ ___________ about how to stay alive, essentially. Just imagine a mosquito. Imagine you're a mosquito, and you've just flown in from outside and you've entered this room. You're going to be ________ a really complex world. You're going to be bombarded with smells from everywhere. We've just found out that we're really ______ beasts. Each one of us is producing 500-600 different volatile chemicals. It's not just one chemical like BO, lots and lots of chemicals. But it's not just you, it's these seats you're sitting on, the ______, the glue that holds the carpet to the floor, the _____ on the walls, the trees outside, everything around you is producing an odour, and it's a really complex world that the mosquito has to fly through, and it has to find you within that really _______ _____. And each and every one of you will know - C'mon, hands up, who always get bitten by mosquitoes? And _____ up, who never get bitten? There's always one or two really annoying people that never get bitten. But the mosquito has a really hard job to find you, and that's all to do with the way you smell. People who don't attract mosquitoes smell _________, and what we know is - (Laughter) I should clarify: repellent to mosquitoes, not to people. And what we know now is that is actually controlled by our genes. But mosquitoes are able to do that because they have a ______ sophisticated sense of smell, and they're able to see through all this sort of odour sludge to find you, that individual, and bite you as a blood meal. But what would happen if one of you was infected with malaria? Well, let's just have a quick look at the malaria life cycle. So it's quite complex, but basically what happens is: a mosquito has to bite somebody to become infected. Once it bites an infected person, the parasites travel through the mouth part into the gut, and then bursts through the gut, creates cysts, and then the parasites replicate, and then they make a journey from the gut all the way to the salivary ______, where they are then injected back into another ______ when the mosquito bites because it injects saliva as it bites. Then inside the human it goes through a whole other cycle, a whole other part of the life cycle. So it goes through a liver stage, changes shape and then comes out into the bloodstream again, and __________ that person will become infectious. Now, one thing we know about the parasite world is that they are __________ good at manipulating their hosts to enhance their own transmission, to make sure that they get passed onwards. If this was to happen in the malaria ______, it might make sense that it would be something to do with odour that they manipulate because odour is the key, odour's the thing that links us between mosquitoes; that's how they find us. This is what we call the malaria manipulation hypothesis, and it's something that we've been working on over the last few years. So one of the first things that we wanted to do in our study was to find out whether an _________ with malaria actually makes you more attractive to mosquitoes or not. So in Kenya with our colleagues, we designed an experiment where we had ____________, children in _____, sleep inside tents. The odour from the tent was blown into a chamber which contained mosquitoes. And the mosquitoes would behaviourally respond - they would fly towards or fly away from the odours depending on whether they liked them or not. Now, some of the participants were ________ with malaria and some of them were uninfected. But importantly, none of the children had any symptoms whatsoever. Now, when we found and saw the results, it was really quite staggering. People who were infected with malaria were _____________ more attractive than people who were __________. Let me explain this graph. We have a number of mosquitoes attracted to the child, and we have two sets of data: before treatment and after treatment. On the far left hand side, that bar represents somebody - or a group of people who are uninfected. And as we move towards the right hand side these people have become infected, and they're ______ towards the stage that they're infectious. So right at the stage when people are infectious is when they are significantly more __________. In this study then what we did is we obviously gave the children treatment to clear the parasites, and then we ______ them again. And what we found was that highly attractive trait that was there disappeared after they had _______ the infection, so it wasn't just that the people were more attractive, it was that the parasite was manipulating its host in some way to make it more attractive to mosquitoes, standing out like a beacon to attract more mosquitoes so that it could continue its life _____. The next thing we wanted to do was find out what it was the mosquito was actually smelling. What was it detecting? So to do that we had to collect the body odour from the participants. And we did this by wrapping bags around their feet, which allowed us to collect the volatile odours from their feet. And feet's really important to __________. They really love the smell of feet. (Laughter) Especially cheesy feet. Anybody got cheesy feet out there? Mosquitoes love that smell. So we focused on the feet and we _________ the body odour. Now, when it comes to mosquitoes and olfaction, their sense of _____, it's very complex. It would be really nice if there was just one ________ that they detected, but it's not that simple. They have to ______ a number of chemicals in the right concentration, the right ratios, the right combinations of chemicals. So you can sort of think about it like a musical ___________. So, you know, if you get the note wrong or you play it too loud or too soft, it doesn't sound right. Or a ______, if you get an ingredient wrong, or you cook it too long or too little, it doesn't _____ right. Well, smell is the same, it's made up of a _____ of chemicals in the right combination. Now, our machines in the lab are not particularly good at picking out this sort of signal; it's quite complex. But animals can. And what we do in my laboratory is we connect _______________ to the antenna of a mosquito - imagine how fiddly that is. (Laughter) But what we also do is connect them to individual _____ within the antenna, which is incredible. You definitely don't want to ______ when you're doing this experiment, that's for sure. But what this does is it allows us to _______ the electrical response of the smell receptors in the antennae, and so that we can see what a mosquito is ________. I'm going to show you what this looks like: here's an insect's cell, and it's responding; it will respond in a second when I press this ______. You'll see it sort of ticking over with this response. An _____ will be blown over the cell, and it will sort of go a bit crazy, sort of blow a raspberry. Then it will go back to its _______ potential when we stop the odour. (Clicking) Okay, there we go. So you can go home now and say that you've now seen an ______ smelling and even hearing an insect smelling. It's a weird concept, isn't it? But this works really well, and this allows us to see what the insect is detecting. Now, using this method with our malaria _______, we were able to find out what the mosquito was detecting. And we found the malaria associated compounds were a group of compounds, mainly aldehydes, a _____ of compounds that smelled, that signified the malaria at ______ here. So now we know what the smell of malaria is, and we've used the ________ as a bio-sensor to tell us what the smell of malaria actually is. Now, I'd like to imagine that you could, I don't know, put a harness on a little mosquito and, you know, put it on a lead and take it out and see if we can sniff ______ in a community - that goes on in my head - and see whether we could actually find people with malaria. But, of course, that's not really possible. But there is an animal that we can do that with. Awww. (________) Yes. Now, dogs have an incredible sense of smell, but there's something a little bit more _______ about them, they have an ability to learn. And most of you will be familiar with this concept at airports, where dogs will go down a line and sniff out your luggage or yourself for drugs and explosives or even food as well. So we wanted to know: Could we actually _____ dogs to _____ the smell of malaria? And so we've been working with a _______ called Medical Detection Dogs to see whether we can train them to learn the smell of malaria. And we went out to the ______ and did some more odour __________ on children that were infected and uninfected. But this time we collected their odour by ______ them wear socks, nylon stockings to collect their body odour, and we brought them back to the UK, and then we handed them to this charity to run the experiment. Now, I could show you a graph and tell you about how that experiment works, but it'd be a bit dull, wouldn't it? Now, they do say never work with children or animals live. But we're going to break that rule today. So, please welcome onto the stage, Freya (Applause) and her trainer, (Applause) Mark, and Sarah. Of course this is the real star of the show. Okay so, now what I'm going to ask is if you can all just be a little bit quiet, don't move around too much. This is a very strange ___________ for Freya. She's having a good look at you guys now. So let's stay as calm as possible; that would be great. So what we're going to do here is we're going to ask Freya to move down this line of contraptions here. And in each one of these contraptions we have a pot. In the pot is a sock that's been worn by a _____ in The Gambia. Now, three of the _____ had been worn by children who were uninfected, and just one of the socks was worn by a child who was infected with malaria. So just as you'd see an airport, imagine these were people, and the dog is going to go down and have a good sniff. And let's see if you can see when she senses the malaria. And if she ______ it in there. This is a really tough test for her in this very strange environment. So I'm going to hand over now to Mark. (Laughter) Number three. Okay, there we go. (Applause) I didn't know which pot that was in. Mark didn't know which pot that was in. This was a blind test, genuinely. Sarah, was that correct? That was _______. Well done, Freya! That is fantastic. (________) Whew! That is really _________. Okay, that's brilliant. Now what we're going to do is Sarah's going to change the pots around a little bit; she's going to take the one with malaria away. And we're just going to have four pots that are containing socks from children that had no malaria. So in theory, Freya should go down the line and not stop at all. This is really important because we also need to know people who are not infected; she needs to be able to do that correctly as well. This is a really tough test. These socks have been in the freezer for a couple of years now. And this is a tiny bit of a sock as well, so _______ if this was a whole person and they were giving off a big signal. So this is really quite incredible. Okay, over to you, Mark. Brilliant! Fantastic! (Applause) Really super! Thank you so much, guys. Big round of applause for _____, Mark and Sarah! Well done, guys. (Applause) What a good girl. She's going to get a _____ later. Fantastic. So, you've just seen that for your own eyes. That was a real live demonstration. I was quite _______ about it. I'm so glad that it worked. (Laughter) But it is really incredible, and when we do this, what we find is that these dogs can _________ tell us when somebody's infected with malaria 81% of the time. It's incredible! 92% of the time, they can tell us correctly when somebody does not have an infection. And those _______ are actually above the criteria set by the World ______ ____________ for a diagnostic. So we really are looking at deploying dogs in _________, and particularly at ports of entry, to detect people who have malaria. This could be a reality. But we can't deploy dogs everywhere. So what we're also looking to do and working on at the moment is the development of technology, wearable tech that would empower the individual to allow them to self-diagnose. Imagine a patch that you wear on the skin that would detect in your sweat when you're infected with malaria and ______ colour. Or something a little bit more technical perhaps, a smartwatch that would alert you when you're infected with malaria. And if we can do this digitally, and we can collect data, imagine the ______ of data that we can collect on a ______ scale. This could completely revolutionise the way that we track the spread of diseases, the way that we ______ our control efforts and respond to disease outbreaks, __________ _______ to lead to the eradication of _______, and even beyond malaria for other diseases that we already know have a smell. If we can _______ the _____ of nature to find out what those smells are, we could do this and make this a reality. Now, as __________, we're tasked with coming up with new ideas, new concepts, new ____________, to tackle some of the world's ________ problems. But what never ceases to amaze me is that often, nature has already done this for us. And the ______ is right under our nose. Thank you. (Applause) (Cheers)

Solution

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Original Text

But some of us might've smelt something a little bit less pleasant, perhaps - perhaps somebody's bad breath or body odour. Maybe you even smelled your own body odour. But there's probably a good reason that some of us don't like certain body smells. Throughout history, there had been many examples of diseases being associated with a smell. So for example, typhoid apparently smells like baked brown bread. Well, that's quite a nice smell, isn't it? But it starts to get a little bit worse. TB smells like stale beer, and yellow fever smells like the inside of a butcher shop, like raw meat. And in fact, when you look at the sort of words used to describe diseases, you tend to find these words: rotting, foul, putrid or pungent. So it's no surprise then, that smell and body odour gets a bit of a bad reputation. If I was to say to you: 'You smell', you're going to take that not exactly as a compliment, are you? But you do smell, you've just found that out, you do smell. It's a scientific fact. I'd quite like to turn that on its head. What if we could actually think about smell in a positive way? What if we could put it to good use? What if we could detect the chemicals that are given off by our bodies when we're ill and use that to diagnose people? Now, we'd need to develop good sensors that would allow us to do this. But it turns out that the world's best sensors actually already exist. And they're called 'animals'. Now, animals are built to smell. They live their everyday lives according to their nose. They sense the environments, which tells them really important information about how to stay alive, essentially. Just imagine a mosquito. Imagine you're a mosquito, and you've just flown in from outside and you've entered this room. You're going to be entering a really complex world. You're going to be bombarded with smells from everywhere. We've just found out that we're really smelly beasts. Each one of us is producing 500-600 different volatile chemicals. It's not just one chemical like BO, lots and lots of chemicals. But it's not just you, it's these seats you're sitting on, the carpet, the glue that holds the carpet to the floor, the paint on the walls, the trees outside, everything around you is producing an odour, and it's a really complex world that the mosquito has to fly through, and it has to find you within that really complex world. And each and every one of you will know - C'mon, hands up, who always get bitten by mosquitoes? And hands up, who never get bitten? There's always one or two really annoying people that never get bitten. But the mosquito has a really hard job to find you, and that's all to do with the way you smell. People who don't attract mosquitoes smell repellent, and what we know is - (Laughter) I should clarify: repellent to mosquitoes, not to people. And what we know now is that is actually controlled by our genes. But mosquitoes are able to do that because they have a highly sophisticated sense of smell, and they're able to see through all this sort of odour sludge to find you, that individual, and bite you as a blood meal. But what would happen if one of you was infected with malaria? Well, let's just have a quick look at the malaria life cycle. So it's quite complex, but basically what happens is: a mosquito has to bite somebody to become infected. Once it bites an infected person, the parasites travel through the mouth part into the gut, and then bursts through the gut, creates cysts, and then the parasites replicate, and then they make a journey from the gut all the way to the salivary glands, where they are then injected back into another person when the mosquito bites because it injects saliva as it bites. Then inside the human it goes through a whole other cycle, a whole other part of the life cycle. So it goes through a liver stage, changes shape and then comes out into the bloodstream again, and eventually that person will become infectious. Now, one thing we know about the parasite world is that they are incredibly good at manipulating their hosts to enhance their own transmission, to make sure that they get passed onwards. If this was to happen in the malaria system, it might make sense that it would be something to do with odour that they manipulate because odour is the key, odour's the thing that links us between mosquitoes; that's how they find us. This is what we call the malaria manipulation hypothesis, and it's something that we've been working on over the last few years. So one of the first things that we wanted to do in our study was to find out whether an infection with malaria actually makes you more attractive to mosquitoes or not. So in Kenya with our colleagues, we designed an experiment where we had participants, children in Kenya, sleep inside tents. The odour from the tent was blown into a chamber which contained mosquitoes. And the mosquitoes would behaviourally respond - they would fly towards or fly away from the odours depending on whether they liked them or not. Now, some of the participants were infected with malaria and some of them were uninfected. But importantly, none of the children had any symptoms whatsoever. Now, when we found and saw the results, it was really quite staggering. People who were infected with malaria were significantly more attractive than people who were uninfected. Let me explain this graph. We have a number of mosquitoes attracted to the child, and we have two sets of data: before treatment and after treatment. On the far left hand side, that bar represents somebody - or a group of people who are uninfected. And as we move towards the right hand side these people have become infected, and they're moving towards the stage that they're infectious. So right at the stage when people are infectious is when they are significantly more attractive. In this study then what we did is we obviously gave the children treatment to clear the parasites, and then we tested them again. And what we found was that highly attractive trait that was there disappeared after they had cleared the infection, so it wasn't just that the people were more attractive, it was that the parasite was manipulating its host in some way to make it more attractive to mosquitoes, standing out like a beacon to attract more mosquitoes so that it could continue its life cycle. The next thing we wanted to do was find out what it was the mosquito was actually smelling. What was it detecting? So to do that we had to collect the body odour from the participants. And we did this by wrapping bags around their feet, which allowed us to collect the volatile odours from their feet. And feet's really important to mosquitoes. They really love the smell of feet. (Laughter) Especially cheesy feet. Anybody got cheesy feet out there? Mosquitoes love that smell. So we focused on the feet and we collected the body odour. Now, when it comes to mosquitoes and olfaction, their sense of smell, it's very complex. It would be really nice if there was just one chemical that they detected, but it's not that simple. They have to detect a number of chemicals in the right concentration, the right ratios, the right combinations of chemicals. So you can sort of think about it like a musical composition. So, you know, if you get the note wrong or you play it too loud or too soft, it doesn't sound right. Or a recipe, if you get an ingredient wrong, or you cook it too long or too little, it doesn't taste right. Well, smell is the same, it's made up of a suite of chemicals in the right combination. Now, our machines in the lab are not particularly good at picking out this sort of signal; it's quite complex. But animals can. And what we do in my laboratory is we connect microelectrodes to the antenna of a mosquito - imagine how fiddly that is. (Laughter) But what we also do is connect them to individual cells within the antenna, which is incredible. You definitely don't want to sneeze when you're doing this experiment, that's for sure. But what this does is it allows us to measure the electrical response of the smell receptors in the antennae, and so that we can see what a mosquito is smelling. I'm going to show you what this looks like: here's an insect's cell, and it's responding; it will respond in a second when I press this button. You'll see it sort of ticking over with this response. An odour will be blown over the cell, and it will sort of go a bit crazy, sort of blow a raspberry. Then it will go back to its resting potential when we stop the odour. (Clicking) Okay, there we go. So you can go home now and say that you've now seen an insect smelling and even hearing an insect smelling. It's a weird concept, isn't it? But this works really well, and this allows us to see what the insect is detecting. Now, using this method with our malaria samples, we were able to find out what the mosquito was detecting. And we found the malaria associated compounds were a group of compounds, mainly aldehydes, a group of compounds that smelled, that signified the malaria at signal here. So now we know what the smell of malaria is, and we've used the mosquito as a bio-sensor to tell us what the smell of malaria actually is. Now, I'd like to imagine that you could, I don't know, put a harness on a little mosquito and, you know, put it on a lead and take it out and see if we can sniff people in a community - that goes on in my head - and see whether we could actually find people with malaria. But, of course, that's not really possible. But there is an animal that we can do that with. Awww. (Laughter) Yes. Now, dogs have an incredible sense of smell, but there's something a little bit more special about them, they have an ability to learn. And most of you will be familiar with this concept at airports, where dogs will go down a line and sniff out your luggage or yourself for drugs and explosives or even food as well. So we wanted to know: Could we actually train dogs to learn the smell of malaria? And so we've been working with a charity called Medical Detection Dogs to see whether we can train them to learn the smell of malaria. And we went out to the Gambia and did some more odour collection on children that were infected and uninfected. But this time we collected their odour by making them wear socks, nylon stockings to collect their body odour, and we brought them back to the UK, and then we handed them to this charity to run the experiment. Now, I could show you a graph and tell you about how that experiment works, but it'd be a bit dull, wouldn't it? Now, they do say never work with children or animals live. But we're going to break that rule today. So, please welcome onto the stage, Freya (Applause) and her trainer, (Applause) Mark, and Sarah. Of course this is the real star of the show. Okay so, now what I'm going to ask is if you can all just be a little bit quiet, don't move around too much. This is a very strange environment for Freya. She's having a good look at you guys now. So let's stay as calm as possible; that would be great. So what we're going to do here is we're going to ask Freya to move down this line of contraptions here. And in each one of these contraptions we have a pot. In the pot is a sock that's been worn by a child in The Gambia. Now, three of the socks had been worn by children who were uninfected, and just one of the socks was worn by a child who was infected with malaria. So just as you'd see an airport, imagine these were people, and the dog is going to go down and have a good sniff. And let's see if you can see when she senses the malaria. And if she senses it in there. This is a really tough test for her in this very strange environment. So I'm going to hand over now to Mark. (Laughter) Number three. Okay, there we go. (Applause) I didn't know which pot that was in. Mark didn't know which pot that was in. This was a blind test, genuinely. Sarah, was that correct? That was correct. Well done, Freya! That is fantastic. (Applause) Whew! That is really wonderful. Okay, that's brilliant. Now what we're going to do is Sarah's going to change the pots around a little bit; she's going to take the one with malaria away. And we're just going to have four pots that are containing socks from children that had no malaria. So in theory, Freya should go down the line and not stop at all. This is really important because we also need to know people who are not infected; she needs to be able to do that correctly as well. This is a really tough test. These socks have been in the freezer for a couple of years now. And this is a tiny bit of a sock as well, so imagine if this was a whole person and they were giving off a big signal. So this is really quite incredible. Okay, over to you, Mark. Brilliant! Fantastic! (Applause) Really super! Thank you so much, guys. Big round of applause for Freya, Mark and Sarah! Well done, guys. (Applause) What a good girl. She's going to get a treat later. Fantastic. So, you've just seen that for your own eyes. That was a real live demonstration. I was quite nervous about it. I'm so glad that it worked. (Laughter) But it is really incredible, and when we do this, what we find is that these dogs can correctly tell us when somebody's infected with malaria 81% of the time. It's incredible! 92% of the time, they can tell us correctly when somebody does not have an infection. And those numbers are actually above the criteria set by the World Health Organization for a diagnostic. So we really are looking at deploying dogs in countries, and particularly at ports of entry, to detect people who have malaria. This could be a reality. But we can't deploy dogs everywhere. So what we're also looking to do and working on at the moment is the development of technology, wearable tech that would empower the individual to allow them to self-diagnose. Imagine a patch that you wear on the skin that would detect in your sweat when you're infected with malaria and change colour. Or something a little bit more technical perhaps, a smartwatch that would alert you when you're infected with malaria. And if we can do this digitally, and we can collect data, imagine the amount of data that we can collect on a global scale. This could completely revolutionise the way that we track the spread of diseases, the way that we target our control efforts and respond to disease outbreaks, ultimately helping to lead to the eradication of malaria, and even beyond malaria for other diseases that we already know have a smell. If we can harness the power of nature to find out what those smells are, we could do this and make this a reality. Now, as scientists, we're tasked with coming up with new ideas, new concepts, new technologies, to tackle some of the world's greatest problems. But what never ceases to amaze me is that often, nature has already done this for us. And the answer is right under our nose. Thank you. (Applause) (Cheers)

Frequently Occurring Word Combinations

ngrams of length 2

collocation	frequency
body odour	5
complex world	3
life cycle	3
cheesy feet	2
insect smelling	2
strange environment	2
tough test	2

Important Words

ability
airport
airports
aldehydes
alert
alive
allowed
amaze
amount
animal
animals
annoying
answer
antenna
antennae
apparently
applause
attract
attracted
attractive
awww
bad
bags
baked
bar
basically
beacon
beasts
beer
behaviourally
big
bit
bite
bites
bitten
blind
blood
bloodstream
blow
blown
bo
bodies
body
bombarded
bread
break
breath
brilliant
brought
brown
built
bursts
butcher
button
call
called
calm
carpet
ceases
cell
cells
chamber
change
charity
cheers
cheesy
chemical
chemicals
child
children
clear
cleared
clicking
colleagues
collect
collected
collection
colour
combination
combinations
coming
community
completely
complex
compliment
composition
compounds
concentration
concept
concepts
connect
contained
continue
contraptions
control
controlled
cook
correct
correctly
countries
couple
crazy
creates
criteria
cycle
cysts
data
demonstration
depending
deploy
deploying
describe
designed
detect
detected
detecting
detection
develop
development
diagnose
diagnostic
digitally
disappeared
disease
diseases
dog
dogs
drugs
dull
efforts
electrical
empower
enhance
entered
entering
entry
environment
environments
eradication
essentially
eventually
everyday
examples
exist
experiment
explain
explosives
eyes
fact
familiar
fantastic
feet
fever
fiddly
find
floor
flown
fly
focused
food
foul
freezer
freya
gambia
gave
genes
genuinely
girl
giving
glad
glands
global
glue
good
graph
great
greatest
group
gut
guys
hand
handed
hands
happen
hard
harness
head
health
hearing
helping
highly
history
holds
home
host
hosts
human
hypothesis
ideas
ill
imagine
important
importantly
incredible
incredibly
individual
infected
infection
infectious
information
ingredient
injected
injects
insect
job
journey
kenya
key
lab
laboratory
laughter
lead
learn
left
life
line
links
live
liver
lives
long
lots
loud
love
luggage
machines
making
malaria
manipulate
manipulating
manipulation
mark
meal
measure
meat
medical
method
microelectrodes
moment
mosquito
mosquitoes
mouth
move
moving
musical
nature
nervous
nice
nose
note
number
numbers
nylon
odour
odours
olfaction
onwards
organization
outbreaks
paint
parasite
parasites
part
participants
passed
patch
people
person
picking
play
pleasant
ports
positive
pot
potential
pots
power
press
problems
producing
pungent
put
putrid
quick
quiet
raspberry
ratios
raw
real
reality
reason
receptors
recipe
repellent
replicate
represents
reputation
respond
response
resting
results
revolutionise
room
rotting
rule
run
saliva
salivary
samples
sarah
scale
scientific
scientists
seats
sense
senses
sensors
set
sets
shape
shop
show
side
signal
significantly
signified
simple
sitting
skin
sleep
sludge
smartwatch
smell
smelled
smelling
smells
smelly
smelt
sneeze
sniff
sock
socks
soft
sophisticated
sort
sound
special
spread
stage
staggering
stale
standing
star
starts
stay
stockings
stop
strange
study
suite
surprise
sweat
symptoms
system
tackle
target
tasked
taste
tb
tech
technical
technologies
technology
tells
tend
tent
tents
test
tested
theory
ticking
time
tiny
today
tough
track
train
trainer
trait
transmission
travel
treat
treatment
trees
turn
turns
typhoid
uk
ultimately
uninfected
volatile
walls
wanted
wear
wearable
weird
whatsoever
wonderful
words
work
worked
working
works
world
worn
worse
wrapping
wrong
years
yellow