full transcript

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 smells. Throughout history, there had been many exaplems of daeessis being associated with a smell. So for example, typhoid apparently selmls 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 fveer 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: rotntig, foul, putrid or pngenut. 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 beoids 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 caleld 'animals'. Now, alminas are built to smell. They live their everyday lvies according to their nose. They sense the environments, which tells them really important information about how to stay aivle, 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 cahcmiel like BO, lots and lots of cicelmhas. But it's not just you, it's these staes you're sitting on, the carpet, the glue that holds the carpet to the folor, the paint on the walls, the trees outside, everything around you is pudcnoirg 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: relneeplt to mosquitoes, not to people. And what we know now is that is actually controlled by our genes. But meutqsioos 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 slduge 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 psertiaas travel through the mouth part into the gut, and then bsruts through the gut, ceearts cysts, and then the parasites replicate, and then they make a jneruoy from the gut all the way to the saivlary 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 clcye, a whole other part of the life cycle. So it goes through a lvier 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 wolrd is that they are incredibly good at manipulating their htoss to enhance their own transmission, to make sure that they get pssead 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 muanlitape because odour is the key, odour's the thing that lkins 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 yaers. So one of the first things that we wanted to do in our study was to find out whether an infection with miarala actually makes you more attractive to mosquitoes or not. So in kyena with our colleagues, we dieensgd an epemrixent where we had participants, children in Kenya, selep inside ttens. The odour from the tent was blown into a chamber which caoienntd 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 irtnoplatmy, none of the children had any symptoms whatsoever. Now, when we found and saw the results, it was really quite staggering. ppoele who were infected with malaria were significantly more arcitttvae than people who were uninfected. Let me explain this graph. We have a number of mosquitoes attracted to the cilhd, 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 sgtae when people are infectious is when they are significantly more attractive. In this study then what we did is we obviously gave the children teertanmt to caelr the parasites, and then we tested them again. And what we found was that highly attractive triat 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 coinutne 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 paptairtnics. 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 imprtonat to mosquitoes. They really love the smell of feet. (Laughter) Especially cheesy feet. Anybody got cesehy 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 ofcaitlon, 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 wnrog, or you cook it too long or too little, it doesn't tatse 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 cemoplx. 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 prses this button. You'll see it sort of ticking over with this rpesnsoe. An odour will be blown over the cell, and it will sort of go a bit carzy, sort of blow a raspberry. Then it will go back to its rtniesg 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 slilenmg and even hearing an inscet smelling. It's a wierd concept, isn't it? But this wkors really well, and this allows us to see what the insect is detecting. Now, using this mhetod 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 aledyedhs, 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 mstuioqo 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 scaiepl 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 lrean the smell of malaria? And so we've been working with a carhity called Medical dotceetin Dogs to see whether we can train them to learn the slmel of malaria. And we went out to the Gambia and did some more odour collection on children that were iectnefd and uninfected. But this time we ctllecoed their odour by mkniag them wear socks, nylon stockings to clceolt 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 cihdelrn 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 sraah. 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 sckos was worn by a child who was infected with malaria. So just as you'd see an arrpiot, 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 tuogh test for her in this very strange environment. So I'm going to hand over now to Mark. (lthuager) nmebur 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 fasattnic. (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, feyra 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 cpoule 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 iblneidrce, 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 crlotecry 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 tghnoceloy, 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 sawet when you're infected with malaria and cgnhae colour. Or something a little bit more tcacniehl 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, igiamne the amount of data that we can collect on a global scale. This could cepmetolly rooiliseutvne the way that we track the spread of diseases, the way that we target our control efforts and rpesond to disease outbreaks, ultimately helping to lead to the eioaatrdcin 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 tghoenolecis, to tackle some of the world's greatest problems. But what never ceaess to amaze me is that often, naurte has already done this for us. And the answer is right under our nose. Thank you. (Applause) (cehers)

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 smells. Throughout history, there had been many ________ of ________ being associated with a smell. So for example, typhoid apparently ______ 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 words 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 ______ 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 ______ 'animals'. Now, _______ are built to smell. They live their everyday _____ according to their nose. They sense the environments, which tells them really important information about how to stay _____, 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 ________ like BO, lots and lots of _________. But it's not just you, it's these _____ you're sitting on, the carpet, the glue that holds the carpet to the _____, the paint on the walls, the trees outside, everything around you is _________ 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: _________ to mosquitoes, not to people. And what we know now is that is actually controlled by our genes. But __________ 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 ______ 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 _________ travel through the mouth part into the gut, and then ______ through the gut, _______ cysts, and then the parasites replicate, and then they make a _______ from the gut all the way to the ________ 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 _____, a whole other part of the life cycle. So it goes through a _____ 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 _____ is that they are incredibly good at manipulating their _____ to enhance their own transmission, to make sure that they get ______ 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 __________ because odour is the key, odour's the thing that _____ 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 _____. So one of the first things that we wanted to do in our study was to find out whether an infection with _______ actually makes you more attractive to mosquitoes or not. So in _____ with our colleagues, we ________ an __________ where we had participants, children in Kenya, _____ inside _____. The odour from the tent was blown into a chamber which _________ 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 ___________, none of the children had any symptoms whatsoever. Now, when we found and saw the results, it was really quite staggering. ______ who were infected with malaria were significantly more __________ than people who were uninfected. Let me explain this graph. We have a number of mosquitoes attracted to the _____, 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 _____ when people are infectious is when they are significantly more attractive. In this study then what we did is we obviously gave the children _________ to _____ the parasites, and then we tested them again. And what we found was that highly attractive _____ 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 ________ 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 ____________. 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 _________ to mosquitoes. They really love the smell of feet. (Laughter) Especially cheesy feet. Anybody got ______ 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 _________, 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 _____, or you cook it too long or too little, it doesn't _____ 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 _______. 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 _____ this button. You'll see it sort of ticking over with this ________. An odour will be blown over the cell, and it will sort of go a bit _____, 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 insect ________ and even hearing an ______ smelling. It's a _____ concept, isn't it? But this _____ really well, and this allows us to see what the insect is detecting. Now, using this ______ 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 _________, 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 ________ 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 _______ 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 _____ the smell of malaria? And so we've been working with a _______ called Medical _________ Dogs to see whether we can train them to learn the _____ of malaria. And we went out to the Gambia and did some more odour collection on children that were ________ and uninfected. But this time we _________ their odour by ______ them wear socks, nylon stockings to _______ 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 ________ 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 _____. 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 _____ was worn by a child who was infected with malaria. So just as you'd see an _______, 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 _____ test for her in this very strange environment. So I'm going to hand over now to Mark. (________) ______ 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 _________. (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, _____ 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 ______ 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 __________, 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 _________ 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 __________, 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 _____ when you're infected with malaria and ______ colour. Or something a little bit more _________ 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, _______ the amount of data that we can collect on a global scale. This could __________ _____________ the way that we track the spread of diseases, the way that we target our control efforts and _______ to disease outbreaks, ultimately helping to lead to the ___________ 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 ____________, to tackle some of the world's greatest problems. But what never ______ to amaze me is that often, ______ has already done this for us. And the answer is right under our nose. Thank you. (Applause) (______)

Solution

  1. pungent
  2. complex
  3. clear
  4. tough
  5. smell
  6. children
  7. special
  8. importantly
  9. sarah
  10. fever
  11. contained
  12. called
  13. diseases
  14. examples
  15. cycle
  16. insect
  17. taste
  18. passed
  19. collected
  20. journey
  21. nature
  22. bodies
  23. bursts
  24. important
  25. animals
  26. hosts
  27. wrong
  28. airport
  29. attractive
  30. tents
  31. imagine
  32. sleep
  33. couple
  34. weird
  35. making
  36. works
  37. ceases
  38. sweat
  39. stage
  40. fantastic
  41. chemical
  42. experiment
  43. eradication
  44. change
  45. infected
  46. correctly
  47. lives
  48. mosquitoes
  49. learn
  50. alive
  51. repellent
  52. laughter
  53. aldehydes
  54. freya
  55. charity
  56. manipulate
  57. links
  58. technical
  59. participants
  60. technology
  61. continue
  62. parasites
  63. malaria
  64. technologies
  65. chemicals
  66. completely
  67. salivary
  68. trait
  69. smells
  70. number
  71. detection
  72. respond
  73. press
  74. smelling
  75. world
  76. liver
  77. mosquito
  78. treatment
  79. rotting
  80. people
  81. kenya
  82. resting
  83. designed
  84. response
  85. cheesy
  86. olfaction
  87. socks
  88. crazy
  89. years
  90. incredible
  91. floor
  92. seats
  93. producing
  94. creates
  95. method
  96. child
  97. revolutionise
  98. collect
  99. cheers
  100. sludge

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

  1. ability
  2. airport
  3. airports
  4. aldehydes
  5. alert
  6. alive
  7. allowed
  8. amaze
  9. amount
  10. animal
  11. animals
  12. annoying
  13. answer
  14. antenna
  15. antennae
  16. apparently
  17. applause
  18. attract
  19. attracted
  20. attractive
  21. awww
  22. bad
  23. bags
  24. baked
  25. bar
  26. basically
  27. beacon
  28. beasts
  29. beer
  30. behaviourally
  31. big
  32. bit
  33. bite
  34. bites
  35. bitten
  36. blind
  37. blood
  38. bloodstream
  39. blow
  40. blown
  41. bo
  42. bodies
  43. body
  44. bombarded
  45. bread
  46. break
  47. breath
  48. brilliant
  49. brought
  50. brown
  51. built
  52. bursts
  53. butcher
  54. button
  55. call
  56. called
  57. calm
  58. carpet
  59. ceases
  60. cell
  61. cells
  62. chamber
  63. change
  64. charity
  65. cheers
  66. cheesy
  67. chemical
  68. chemicals
  69. child
  70. children
  71. clear
  72. cleared
  73. clicking
  74. colleagues
  75. collect
  76. collected
  77. collection
  78. colour
  79. combination
  80. combinations
  81. coming
  82. community
  83. completely
  84. complex
  85. compliment
  86. composition
  87. compounds
  88. concentration
  89. concept
  90. concepts
  91. connect
  92. contained
  93. continue
  94. contraptions
  95. control
  96. controlled
  97. cook
  98. correct
  99. correctly
  100. countries
  101. couple
  102. crazy
  103. creates
  104. criteria
  105. cycle
  106. cysts
  107. data
  108. demonstration
  109. depending
  110. deploy
  111. deploying
  112. describe
  113. designed
  114. detect
  115. detected
  116. detecting
  117. detection
  118. develop
  119. development
  120. diagnose
  121. diagnostic
  122. digitally
  123. disappeared
  124. disease
  125. diseases
  126. dog
  127. dogs
  128. drugs
  129. dull
  130. efforts
  131. electrical
  132. empower
  133. enhance
  134. entered
  135. entering
  136. entry
  137. environment
  138. environments
  139. eradication
  140. essentially
  141. eventually
  142. everyday
  143. examples
  144. exist
  145. experiment
  146. explain
  147. explosives
  148. eyes
  149. fact
  150. familiar
  151. fantastic
  152. feet
  153. fever
  154. fiddly
  155. find
  156. floor
  157. flown
  158. fly
  159. focused
  160. food
  161. foul
  162. freezer
  163. freya
  164. gambia
  165. gave
  166. genes
  167. genuinely
  168. girl
  169. giving
  170. glad
  171. glands
  172. global
  173. glue
  174. good
  175. graph
  176. great
  177. greatest
  178. group
  179. gut
  180. guys
  181. hand
  182. handed
  183. hands
  184. happen
  185. hard
  186. harness
  187. head
  188. health
  189. hearing
  190. helping
  191. highly
  192. history
  193. holds
  194. home
  195. host
  196. hosts
  197. human
  198. hypothesis
  199. ideas
  200. ill
  201. imagine
  202. important
  203. importantly
  204. incredible
  205. incredibly
  206. individual
  207. infected
  208. infection
  209. infectious
  210. information
  211. ingredient
  212. injected
  213. injects
  214. insect
  215. job
  216. journey
  217. kenya
  218. key
  219. lab
  220. laboratory
  221. laughter
  222. lead
  223. learn
  224. left
  225. life
  226. line
  227. links
  228. live
  229. liver
  230. lives
  231. long
  232. lots
  233. loud
  234. love
  235. luggage
  236. machines
  237. making
  238. malaria
  239. manipulate
  240. manipulating
  241. manipulation
  242. mark
  243. meal
  244. measure
  245. meat
  246. medical
  247. method
  248. microelectrodes
  249. moment
  250. mosquito
  251. mosquitoes
  252. mouth
  253. move
  254. moving
  255. musical
  256. nature
  257. nervous
  258. nice
  259. nose
  260. note
  261. number
  262. numbers
  263. nylon
  264. odour
  265. odours
  266. olfaction
  267. onwards
  268. organization
  269. outbreaks
  270. paint
  271. parasite
  272. parasites
  273. part
  274. participants
  275. passed
  276. patch
  277. people
  278. person
  279. picking
  280. play
  281. pleasant
  282. ports
  283. positive
  284. pot
  285. potential
  286. pots
  287. power
  288. press
  289. problems
  290. producing
  291. pungent
  292. put
  293. putrid
  294. quick
  295. quiet
  296. raspberry
  297. ratios
  298. raw
  299. real
  300. reality
  301. reason
  302. receptors
  303. recipe
  304. repellent
  305. replicate
  306. represents
  307. reputation
  308. respond
  309. response
  310. resting
  311. results
  312. revolutionise
  313. room
  314. rotting
  315. rule
  316. run
  317. saliva
  318. salivary
  319. samples
  320. sarah
  321. scale
  322. scientific
  323. scientists
  324. seats
  325. sense
  326. senses
  327. sensors
  328. set
  329. sets
  330. shape
  331. shop
  332. show
  333. side
  334. signal
  335. significantly
  336. signified
  337. simple
  338. sitting
  339. skin
  340. sleep
  341. sludge
  342. smartwatch
  343. smell
  344. smelled
  345. smelling
  346. smells
  347. smelly
  348. smelt
  349. sneeze
  350. sniff
  351. sock
  352. socks
  353. soft
  354. sophisticated
  355. sort
  356. sound
  357. special
  358. spread
  359. stage
  360. staggering
  361. stale
  362. standing
  363. star
  364. starts
  365. stay
  366. stockings
  367. stop
  368. strange
  369. study
  370. suite
  371. surprise
  372. sweat
  373. symptoms
  374. system
  375. tackle
  376. target
  377. tasked
  378. taste
  379. tb
  380. tech
  381. technical
  382. technologies
  383. technology
  384. tells
  385. tend
  386. tent
  387. tents
  388. test
  389. tested
  390. theory
  391. ticking
  392. time
  393. tiny
  394. today
  395. tough
  396. track
  397. train
  398. trainer
  399. trait
  400. transmission
  401. travel
  402. treat
  403. treatment
  404. trees
  405. turn
  406. turns
  407. typhoid
  408. uk
  409. ultimately
  410. uninfected
  411. volatile
  412. walls
  413. wanted
  414. wear
  415. wearable
  416. weird
  417. whatsoever
  418. wonderful
  419. words
  420. work
  421. worked
  422. working
  423. works
  424. world
  425. worn
  426. worse
  427. wrapping
  428. wrong
  429. years
  430. yellow