1 00:00:27,900 --> 00:00:33,766 (Mosquito buzzing) 2 00:00:42,040 --> 00:00:43,240 (Swat) 3 00:00:45,580 --> 00:00:46,730 Gotcha. 4 00:00:48,060 --> 00:00:49,260 Mosquitoes. 5 00:00:49,980 --> 00:00:51,180 I hate them. 6 00:00:52,220 --> 00:00:53,420 Don't you? 7 00:00:54,060 --> 00:00:56,676 That awful buzzing sound at night around your ears 8 00:00:56,700 --> 00:00:58,300 that drives you absolutely crazy? 9 00:00:59,380 --> 00:01:01,876 Knowing that she wants to stick a needle in your skin 10 00:01:01,900 --> 00:01:03,100 and suck out your blood? 11 00:01:03,620 --> 00:01:04,819 That's awful, right? 12 00:01:05,379 --> 00:01:09,940 In fact, there's only one good thing I can think of when it gets to mosquitoes. 13 00:01:11,100 --> 00:01:13,020 When they fly into our bedroom at night, 14 00:01:13,900 --> 00:01:15,234 they prefer to bite my wife. 15 00:01:15,701 --> 00:01:16,916 (Laughter) 16 00:01:16,940 --> 00:01:18,396 But that's fascinating, right? 17 00:01:18,420 --> 00:01:21,860 Why does she receive more bites than I do? 18 00:01:22,700 --> 00:01:25,116 And the answer is smell, 19 00:01:25,140 --> 00:01:26,340 the smell of her body. 20 00:01:27,220 --> 00:01:31,076 And since we all smell different and produce chemicals on our skin 21 00:01:31,100 --> 00:01:34,036 that either attract or repel mosquitoes, 22 00:01:34,060 --> 00:01:36,740 some of us are just more attractive than others. 23 00:01:37,460 --> 00:01:42,700 So my wife smells nicer than I do, or I just stink more than she does. 24 00:01:43,660 --> 00:01:49,876 Either way, mosquitoes find us in the dark by sniffing us out. They smell us. 25 00:01:49,900 --> 00:01:53,196 And during my PhD, I wanted to know exactly 26 00:01:53,220 --> 00:01:57,300 what chemicals from our skin African malaria mosquitoes use 27 00:01:57,324 --> 00:01:58,564 to track us down at night. 28 00:01:59,780 --> 00:02:02,420 And there's a whole range of compounds that they do use. 29 00:02:02,860 --> 00:02:04,900 And this was not going to be an easy task. 30 00:02:05,700 --> 00:02:08,740 And therefore we set up various experiments. 31 00:02:09,740 --> 00:02:11,916 Why did we set up these experiments? 32 00:02:11,940 --> 00:02:14,236 Because half the world's population 33 00:02:14,260 --> 00:02:18,556 runs the risk of contracting a killer disease like malaria 34 00:02:18,580 --> 00:02:20,140 through a simple mosquito bite. 35 00:02:20,940 --> 00:02:23,356 Every 30 seconds, somewhere on this planet, 36 00:02:23,380 --> 00:02:25,836 a child dies of malaria, 37 00:02:25,860 --> 00:02:28,756 and Paul Levy this morning, he was talking about the metaphor 38 00:02:28,780 --> 00:02:31,276 of the 727 crashing into the United States. 39 00:02:31,300 --> 00:02:36,956 Well, in Africa, we have the equivalent of seven jumbo 747s 40 00:02:36,980 --> 00:02:38,260 crashing every day. 41 00:02:39,420 --> 00:02:42,715 But perhaps if we can attract these mosquitoes to traps, 42 00:02:42,739 --> 00:02:44,316 bait it with our smell, 43 00:02:44,340 --> 00:02:47,260 we may be able to stop transmission of disease. 44 00:02:48,460 --> 00:02:50,676 Now, solving this puzzle was not an easy thing, 45 00:02:50,700 --> 00:02:53,676 because we produce hundreds of different chemicals on the skin, 46 00:02:53,700 --> 00:02:56,356 but we undertook some remarkable experiments 47 00:02:56,380 --> 00:02:59,676 that managed us to resolve this puzzle very quickly indeed. 48 00:02:59,700 --> 00:03:03,036 First, we observed that not all mosquito species 49 00:03:03,060 --> 00:03:04,980 bite on the same part of the body. 50 00:03:05,700 --> 00:03:06,916 Strange. 51 00:03:06,940 --> 00:03:08,516 So we set up an experiment 52 00:03:08,540 --> 00:03:11,897 where we put a naked volunteer in a large cage, 53 00:03:11,921 --> 00:03:12,936 (Laughter) 54 00:03:12,960 --> 00:03:15,396 and in that cage, we released mosquitoes 55 00:03:15,420 --> 00:03:18,100 to see where they were biting on the body of that person. 56 00:03:18,700 --> 00:03:20,660 And we found some remarkable differences. 57 00:03:21,100 --> 00:03:24,116 On the left here you see the bites 58 00:03:24,140 --> 00:03:26,396 by the Dutch malaria mosquito on this person. 59 00:03:26,420 --> 00:03:29,100 They had a very strong preference for biting on the face. 60 00:03:29,940 --> 00:03:32,436 In contrast, the African malaria mosquito 61 00:03:32,460 --> 00:03:37,636 had a very strong preference for biting the ankles and feet of this person. 62 00:03:37,660 --> 00:03:40,116 And that, of course, we should have known all along, 63 00:03:40,140 --> 00:03:43,276 because they're called mosqui-toes, you see? 64 00:03:43,300 --> 00:03:44,636 (Laughter) 65 00:03:44,660 --> 00:03:45,876 That's right. 66 00:03:45,900 --> 00:03:48,156 (Applause) 67 00:03:48,180 --> 00:03:52,540 And so we started focusing on the smell of feet ... 68 00:03:53,340 --> 00:03:55,156 on the smell of human feet, 69 00:03:55,180 --> 00:03:58,916 until we came across a remarkable statement in the literature 70 00:03:58,940 --> 00:04:02,716 that said that cheese smells after feet 71 00:04:02,740 --> 00:04:04,340 rather than the reverse. 72 00:04:04,940 --> 00:04:06,396 Think of it. 73 00:04:06,420 --> 00:04:08,849 And this triggered us to do a remarkable experiment. 74 00:04:08,873 --> 00:04:13,916 We tried, with a tiny little piece of Limburger cheese, 75 00:04:13,940 --> 00:04:15,700 which smells badly after feet, 76 00:04:16,339 --> 00:04:18,476 to attract African malaria mosquitoes. 77 00:04:18,500 --> 00:04:20,380 And you know what? It worked. 78 00:04:21,540 --> 00:04:24,516 In fact, it worked so well 79 00:04:24,540 --> 00:04:29,076 that now we have a synthetic mixture of the aroma of Limburger cheese 80 00:04:29,100 --> 00:04:30,876 that we're using in Tanzania 81 00:04:30,900 --> 00:04:32,116 and has been shown there 82 00:04:32,140 --> 00:04:36,100 to be two to three times more attractive to mosquitoes than humans. 83 00:04:36,860 --> 00:04:40,356 Limburg, be proud of your cheese, 84 00:04:40,380 --> 00:04:43,516 as it is now used in the fight against malaria. 85 00:04:43,540 --> 00:04:49,798 (Applause) 86 00:04:50,379 --> 00:04:52,499 That's the cheese, just to show you. 87 00:04:53,499 --> 00:04:55,980 My second story is remarkable as well. 88 00:04:56,820 --> 00:04:59,180 It's about man's best friend. It's about dogs. 89 00:05:00,060 --> 00:05:03,420 And I will show you how we can use dogs in the fight against malaria. 90 00:05:04,980 --> 00:05:07,836 One of the best ways of killing mosquitoes 91 00:05:07,860 --> 00:05:11,156 is not to wait until they fly around like adults 92 00:05:11,180 --> 00:05:13,060 and bite people and transmit disease. 93 00:05:13,900 --> 00:05:17,300 It's to kill them when they're still in the water as larvae. 94 00:05:18,020 --> 00:05:19,236 Why? 95 00:05:19,260 --> 00:05:21,620 Because they are just like the CIA. 96 00:05:22,580 --> 00:05:26,556 In that pool of water, these larvae are concentrated. 97 00:05:26,580 --> 00:05:29,236 They're all together there. They are immobile. 98 00:05:29,260 --> 00:05:30,916 They can't escape from that water. 99 00:05:30,940 --> 00:05:32,516 They can't fly. 100 00:05:32,540 --> 00:05:35,236 And they're accessible. 101 00:05:35,260 --> 00:05:39,300 You can actually walk up to that pool and you can kill them there, right? 102 00:05:40,220 --> 00:05:43,836 So the problem that we face with this 103 00:05:43,860 --> 00:05:47,756 is that, throughout the landscape, all these pools of water with the larvae, 104 00:05:47,780 --> 00:05:49,756 they are scattered all over the place, 105 00:05:49,780 --> 00:05:52,996 which makes it very hard for an inspector like this 106 00:05:53,020 --> 00:05:56,580 to actually find all these breeding sites and treat them with insecticides. 107 00:05:57,140 --> 00:06:01,340 And last year we thought very, very hard, how can we resolve this problem? 108 00:06:02,060 --> 00:06:06,516 Until we realized that just like us -- we have a unique smell -- 109 00:06:06,540 --> 00:06:09,820 mosquito larvae also have a very unique smell. 110 00:06:10,580 --> 00:06:12,756 And so we set up another crazy experiment, 111 00:06:12,780 --> 00:06:15,116 because we collected the smell of these larvae, 112 00:06:15,140 --> 00:06:18,420 put it on pieces of cloth, and then did something very remarkable. 113 00:06:19,060 --> 00:06:21,476 Here we have a bar with four holes 114 00:06:21,500 --> 00:06:24,276 and we put the smell of these larvae in the left hole. 115 00:06:24,300 --> 00:06:25,516 Oh, that was very quick. 116 00:06:25,540 --> 00:06:28,676 And then you see the dog. It's called Tweed. It's a border collie. 117 00:06:28,700 --> 00:06:31,316 He's examining these holes and now he's got it already. 118 00:06:31,340 --> 00:06:33,676 He's going back to check the control holes again, 119 00:06:33,700 --> 00:06:35,556 but he's coming back to the first one, 120 00:06:35,580 --> 00:06:37,396 and now he's locking into that smell, 121 00:06:37,420 --> 00:06:41,036 which means that now, we can use dogs with these inspectors 122 00:06:41,060 --> 00:06:44,276 to much better find the breeding sites of mosquitoes in the field, 123 00:06:44,300 --> 00:06:46,700 and therefore have a much bigger impact on malaria. 124 00:06:47,420 --> 00:06:49,036 This lady is Ellen van der Zweep. 125 00:06:49,060 --> 00:06:51,299 She's one of the best dog trainers in the world, 126 00:06:51,323 --> 00:06:53,363 and she believes that we can do a lot more. 127 00:06:54,260 --> 00:06:57,716 Since we also know that people that carry malaria parasites 128 00:06:57,740 --> 00:07:00,596 smell different compared to people that are uninfected, 129 00:07:00,620 --> 00:07:05,020 she's convinced that we can train dogs to find people that carry the parasite. 130 00:07:06,900 --> 00:07:10,316 That means that in a population where malaria has gone down all the way 131 00:07:10,340 --> 00:07:12,756 and there's few people remaining with parasites, 132 00:07:12,780 --> 00:07:14,516 that the dogs can find these people, 133 00:07:14,540 --> 00:07:18,436 we can treat them with antimalarial drugs and give the final blow to malaria. 134 00:07:18,460 --> 00:07:20,740 Man's best friend in the fight against malaria. 135 00:07:22,180 --> 00:07:24,546 My third story is perhaps even more remarkable ... 136 00:07:25,380 --> 00:07:28,856 and, I should say, has never been shown to the public until today. 137 00:07:28,880 --> 00:07:29,881 (Audience cheers) 138 00:07:29,905 --> 00:07:31,105 Yeah. 139 00:07:31,860 --> 00:07:36,836 It's a crazy story, but I believe it's perhaps the best and ultimate revenge 140 00:07:36,860 --> 00:07:38,060 against mosquitoes ever. 141 00:07:38,540 --> 00:07:40,036 In fact, people have told me 142 00:07:40,060 --> 00:07:43,540 that now they will enjoy being bitten by mosquitoes. 143 00:07:44,620 --> 00:07:46,156 And the question of course is, 144 00:07:46,180 --> 00:07:49,340 what would make someone enjoy being bitten by mosquitoes? 145 00:07:49,900 --> 00:07:52,220 And the answer I have right here ... 146 00:07:53,180 --> 00:07:54,622 in my pocket -- 147 00:07:54,646 --> 00:07:55,647 (Laughter) 148 00:07:55,671 --> 00:07:56,871 if I get it. 149 00:07:58,060 --> 00:07:59,260 It's a tablet. 150 00:08:00,100 --> 00:08:01,316 A simple tablet, 151 00:08:01,340 --> 00:08:03,700 and when I take it with water ... 152 00:08:04,580 --> 00:08:06,180 it does miracles. 153 00:08:09,060 --> 00:08:10,340 Thank you. 154 00:08:16,460 --> 00:08:19,380 Now, let me show you how this works. 155 00:08:20,060 --> 00:08:22,780 Here in this box, I have a cage 156 00:08:24,114 --> 00:08:31,092 with several hundred hungry female mosquitoes ... 157 00:08:31,116 --> 00:08:32,395 (Laughter) 158 00:08:32,419 --> 00:08:34,876 that I'm just about to release. 159 00:08:34,900 --> 00:08:36,676 (Laughter) 160 00:08:36,700 --> 00:08:38,041 Just kidding, just kidding. 161 00:08:38,065 --> 00:08:39,436 (Laughter) 162 00:08:39,460 --> 00:08:42,515 What I'm going to show you is, I'm gonna stick my arm into it 163 00:08:42,539 --> 00:08:44,820 and I will show you how quickly they will bite. 164 00:08:45,580 --> 00:08:46,780 There we go. 165 00:08:47,580 --> 00:08:49,771 Don't worry, I do this all the time in the lab. 166 00:08:50,420 --> 00:08:51,620 There we go. 167 00:08:52,660 --> 00:08:53,860 OK. 168 00:08:54,340 --> 00:08:56,340 Now, on the video -- 169 00:08:57,420 --> 00:08:59,236 on the video here, 170 00:08:59,260 --> 00:09:01,396 I'm going to show you exactly the same thing, 171 00:09:01,420 --> 00:09:03,556 except that what I'm showing you on the video 172 00:09:03,580 --> 00:09:06,380 happened one hour after I took the tablet. 173 00:09:06,899 --> 00:09:08,100 Have a look. 174 00:09:08,820 --> 00:09:10,036 That doesn't work. 175 00:09:10,060 --> 00:09:11,259 OK. Sorry about that. 176 00:09:11,700 --> 00:09:14,676 I'm sticking in my arm, I'm giving them a big juicy blood meal, 177 00:09:14,700 --> 00:09:17,196 I'm shaking them off, and we follow them through time 178 00:09:17,220 --> 00:09:19,716 to see these mosquitoes get very, very sick indeed, 179 00:09:19,740 --> 00:09:21,260 here shown in fast motion. 180 00:09:22,020 --> 00:09:25,956 And three hours later, what we see at the bottom of the cage 181 00:09:25,980 --> 00:09:27,180 is dead mosquitoes ... 182 00:09:28,100 --> 00:09:30,060 very dead mosquitoes. 183 00:09:30,900 --> 00:09:32,916 And I'm going to say, ladies and gentlemen, 184 00:09:32,940 --> 00:09:34,940 we have swapped the cards with mosquitoes. 185 00:09:34,964 --> 00:09:38,516 They don't kill us. We kill them. 186 00:09:38,540 --> 00:09:45,540 (Applause) 187 00:09:47,740 --> 00:09:48,940 Now -- 188 00:09:50,060 --> 00:09:53,236 (Laughter) 189 00:09:53,260 --> 00:09:54,780 Maastricht, be prepared. 190 00:09:55,500 --> 00:09:57,396 Now, think of what we can do with this. 191 00:09:57,420 --> 00:09:59,556 We can actually use this to contain outbreaks 192 00:09:59,580 --> 00:10:02,660 of mosquito-born diseases, of epidemics, right? 193 00:10:03,260 --> 00:10:05,276 And better still, imagine what would happen 194 00:10:05,300 --> 00:10:09,500 if, in a very large area, everyone would take this drug, for just three weeks. 195 00:10:10,020 --> 00:10:11,636 That would give us an opportunity 196 00:10:11,660 --> 00:10:13,780 to actually eliminate malaria as a disease. 197 00:10:14,460 --> 00:10:18,396 So cheese, dogs and a pill to kill mosquitoes. 198 00:10:18,420 --> 00:10:21,380 That's the kind of out-of-the-box science that I love doing ... 199 00:10:22,260 --> 00:10:24,236 for the betterment of mankind, 200 00:10:24,260 --> 00:10:25,876 but especially for her, 201 00:10:25,900 --> 00:10:29,796 so that she can grow up in a world without malaria. 202 00:10:29,820 --> 00:10:31,036 Thank you. 203 00:10:31,060 --> 00:10:32,441 (Applause)