1 00:00:03,069 --> 00:00:05,071 NARRATOR: The cold war is history. 2 00:00:06,573 --> 00:00:10,577 But Russia is in the grips of another arms race. 3 00:00:10,577 --> 00:00:12,579 No warheads are involved. 4 00:00:12,579 --> 00:00:15,081 The enemy is a microbe 5 00:00:15,081 --> 00:00:19,085 and the battleground is the human body. 6 00:00:25,091 --> 00:00:26,593 The race between predator and prey 7 00:00:26,593 --> 00:00:30,597 is a driving force in evolution. 8 00:00:38,605 --> 00:00:41,608 But this, too, is a predator. 9 00:00:41,608 --> 00:00:45,111 And we are its prey. 10 00:00:49,115 --> 00:00:51,618 Russia's crowded prisons have spawned the evolution 11 00:00:51,618 --> 00:00:56,623 of a deadly new microbe, resistant to our best medicine. 12 00:00:56,623 --> 00:00:58,625 (men coughing in background) 13 00:01:00,126 --> 00:01:02,128 As it escapes prison walls 14 00:01:02,128 --> 00:01:06,633 it attacks new prey without preference, without warning. 15 00:01:08,134 --> 00:01:10,637 (woman speaking Russian) 16 00:01:10,637 --> 00:01:12,639 TRANSLATOR: Like any medical student 17 00:01:12,639 --> 00:01:14,140 I knew about the disease. 18 00:01:14,140 --> 00:01:16,142 I knew its symptoms. 19 00:01:16,142 --> 00:01:19,145 But I had no idea it could be like this. 20 00:01:20,647 --> 00:01:23,650 NARRATOR: Now the killer is spreading beyond Russia 21 00:01:23,650 --> 00:01:26,653 and everyone is fair game. 22 00:01:30,156 --> 00:01:33,660 The arms race between humans and microbes 23 00:01:33,660 --> 00:01:37,163 cannot be won by drugs alone. 24 00:01:37,163 --> 00:01:40,166 But if we learn to harness evolution 25 00:01:40,166 --> 00:01:43,670 we may reach a truce with our mortal enemies. 26 00:02:30,216 --> 00:02:34,721 NARRATOR: On a misty morning, western Oregon seems a mild place 27 00:02:34,721 --> 00:02:39,726 fit for gentle creatures, like beaver and duck. 28 00:02:39,726 --> 00:02:44,230 Yet this is home to one of the deadliest animals on Earth. 29 00:02:46,232 --> 00:02:50,236 Local legend long hinted at its lethal power. 30 00:02:50,737 --> 00:02:53,740 Eventually, a tale of untimely death 31 00:02:53,740 --> 00:02:56,743 attracted the scrutiny of science. 32 00:02:56,743 --> 00:03:01,247 MAN: When I was an undergraduate student 37 years ago 33 00:03:01,247 --> 00:03:05,752 my professor told me a story about three hunters 34 00:03:05,752 --> 00:03:09,255 out here in the Coast Range being found dead 35 00:03:09,255 --> 00:03:13,259 and there was a newt boiled in their coffeepot. 36 00:03:13,259 --> 00:03:15,762 That's a good one. 37 00:03:15,762 --> 00:03:18,264 MAN: So his question to me was 38 00:03:18,264 --> 00:03:22,769 "Go find out if these newts are poisonous." 39 00:03:22,769 --> 00:03:26,272 NARRATOR: Edmund Brodie Jr. has studied the rough-skinned newt 40 00:03:26,272 --> 00:03:28,274 ever since 41 00:03:28,274 --> 00:03:32,278 the last decade or so with his son, Edmund Brodie III. 42 00:03:32,278 --> 00:03:37,283 It turns out the newt is extremely poisonous. 43 00:03:37,283 --> 00:03:40,787 Its skin glands secrete one of the most potent toxins 44 00:03:40,787 --> 00:03:42,288 found in nature. 45 00:03:43,790 --> 00:03:45,291 When ingested 46 00:03:45,291 --> 00:03:48,795 the toxin can paralyze a victim within minutes 47 00:03:48,795 --> 00:03:52,799 and shut down vital functions within hours. 48 00:03:52,799 --> 00:03:55,802 An amount equivalent to a pinhead 49 00:03:55,802 --> 00:03:58,805 can kill an adult human. 50 00:03:58,805 --> 00:04:06,312 BRODIE JR.: This is probably the most poisonous animal in the world 51 00:04:06,312 --> 00:04:11,818 with enough skin toxin to kill tens of thousands of mice 52 00:04:11,818 --> 00:04:14,821 or perhaps a hundred people. 53 00:04:14,821 --> 00:04:17,323 Of course, they don't bite 54 00:04:17,323 --> 00:04:20,827 so this isn't really dangerous holding it 55 00:04:20,827 --> 00:04:24,330 unless I were to eat it, which I won't. 56 00:04:24,330 --> 00:04:30,336 The question was, why should a small animal like this 57 00:04:30,336 --> 00:04:34,340 be so many times more toxic than necessary 58 00:04:34,841 --> 00:04:37,343 to kill all predators? 59 00:04:37,343 --> 00:04:43,349 Why should a salamander evolve that much toxin? 60 00:04:45,852 --> 00:04:48,855 Yeah, I can smell the secretion. 61 00:04:48,855 --> 00:04:50,356 Don't lick your hands. 62 00:04:50,356 --> 00:04:52,358 (chuckling) 63 00:04:52,358 --> 00:04:53,860 I'll try not to. 64 00:04:59,365 --> 00:05:01,868 NARRATOR: No environmental factor can explain 65 00:05:01,868 --> 00:05:06,372 the evolution of the newt's extreme toxicity. 66 00:05:06,372 --> 00:05:11,878 The Brodies discovered another animal is responsible. 67 00:05:11,878 --> 00:05:13,379 I'm going to head over to these brambles. 68 00:05:13,880 --> 00:05:15,381 Okay. 69 00:05:15,381 --> 00:05:20,887 NARRATOR: The common garter snake thrives in these parts. 70 00:05:20,887 --> 00:05:25,892 Harmless to humans, it feeds on earthworms, frogs and toads. 71 00:05:31,898 --> 00:05:33,900 But there's one prey in the snake's diet 72 00:05:33,900 --> 00:05:37,403 few other predators ever touch. 73 00:05:37,403 --> 00:05:38,404 She's got a food item. 74 00:05:38,404 --> 00:05:39,405 Oh, yeah. 75 00:05:39,405 --> 00:05:40,907 Look at that. 76 00:05:41,407 --> 00:05:42,408 It's a pretty big object. 77 00:05:42,408 --> 00:05:44,911 I don't know if it's big enough to be a newt 78 00:05:44,911 --> 00:05:46,412 but it could be. 79 00:05:48,414 --> 00:05:49,916 Come on, honey. 80 00:05:52,418 --> 00:05:53,419 Here it comes. 81 00:05:53,419 --> 00:05:54,921 Yeah, here it is. 82 00:05:54,921 --> 00:05:55,922 Aha! 83 00:05:55,922 --> 00:05:57,423 How about that? 84 00:05:57,423 --> 00:06:00,927 It had eaten a full-sized male newt. 85 00:06:00,927 --> 00:06:01,928 Yeah. 86 00:06:04,430 --> 00:06:06,933 BRODIE III: This species of garter snake is the predator 87 00:06:06,933 --> 00:06:08,434 that we think is driving the evolution 88 00:06:08,434 --> 00:06:11,437 of the high toxin levels in the newts. 89 00:06:11,437 --> 00:06:13,940 This is the only thing that can survive 90 00:06:13,940 --> 00:06:15,441 an encounter with a newt. 91 00:06:15,441 --> 00:06:17,944 It's the only thing that can therefore represent 92 00:06:17,944 --> 00:06:20,947 a selective pressure for increasing toxicity. 93 00:06:20,947 --> 00:06:22,448 As the snakes get better 94 00:06:22,448 --> 00:06:24,951 at resisting the effects of the toxin 95 00:06:24,951 --> 00:06:27,954 the prey has to evolve higher levels of toxin. 96 00:06:28,454 --> 00:06:29,956 You can think of this 97 00:06:29,956 --> 00:06:32,458 as this sort of escalating- counterescalating arms race 98 00:06:32,458 --> 00:06:35,962 between the predator and the newt, the prey. 99 00:06:35,962 --> 00:06:39,465 NARRATOR: But the toxin does take a toll. 100 00:06:39,465 --> 00:06:41,467 Some snakes are slowed down. 101 00:06:41,467 --> 00:06:43,970 Others are immobilized for a few hours 102 00:06:43,970 --> 00:06:46,472 after eating a newt. 103 00:06:46,472 --> 00:06:47,974 (device beeps) 104 00:06:47,974 --> 00:06:50,476 NARRATOR: In the lab, the Brodies can measure 105 00:06:50,476 --> 00:06:53,479 the garter snake's resistance to the toxin. 106 00:06:53,479 --> 00:06:55,982 They coax a baby snake 107 00:06:55,982 --> 00:06:58,985 down a track wired with motion sensors 108 00:06:58,985 --> 00:07:00,987 and record its time. 109 00:07:00,987 --> 00:07:02,488 Time. 110 00:07:02,488 --> 00:07:03,489 MAN: 3.4. 111 00:07:03,489 --> 00:07:06,492 NARRATOR: Then they inject the snake 112 00:07:06,993 --> 00:07:09,495 with a small amount of purified toxin 113 00:07:09,495 --> 00:07:12,498 to simulate the effects of eating a newt. 114 00:07:12,498 --> 00:07:14,000 (device beeps) 115 00:07:14,000 --> 00:07:15,501 NARRATOR: Now the snake is raced again. 116 00:07:17,003 --> 00:07:18,504 BRODIE JR.: It's aggressive. 117 00:07:18,504 --> 00:07:22,008 Sometimes when they can't crawl, they do that. 118 00:07:22,008 --> 00:07:27,013 NARRATOR: A snake with low resistance can be stalled to a standstill. 119 00:07:27,013 --> 00:07:28,514 MAN: 6.3. 120 00:07:28,514 --> 00:07:29,515 BRODIE III: Oh! 121 00:07:29,515 --> 00:07:30,516 (device beeps) 122 00:07:30,516 --> 00:07:32,518 NARRATOR: A resistant snake 123 00:07:33,019 --> 00:07:35,521 is much less affected by the toxin 124 00:07:35,521 --> 00:07:39,025 but it, too, pays a price. 125 00:07:39,025 --> 00:07:41,027 The more resistant a snake 126 00:07:41,027 --> 00:07:45,531 the more slowly it moves without any toxin. 127 00:07:45,531 --> 00:07:51,037 BRODIE JR.: The snake experiences a cost from evolving the resistance. 128 00:07:51,037 --> 00:07:54,540 That snake would be more susceptible 129 00:07:54,540 --> 00:07:56,042 to its own predators. 130 00:07:56,042 --> 00:07:57,543 4.1. 131 00:07:57,543 --> 00:08:00,046 BRODIE JR.: So there's a trade-off 132 00:08:00,046 --> 00:08:02,048 between speed in a snake 133 00:08:02,048 --> 00:08:05,051 and the level of resistance. 134 00:08:05,051 --> 00:08:07,053 BRODIE III: All through Oregon, you've got this... 135 00:08:07,053 --> 00:08:11,057 BRODIE JR.: We were very surprised to see that the arms race 136 00:08:11,057 --> 00:08:14,560 is a predator evolving to a prey 137 00:08:14,560 --> 00:08:18,564 and a prey evolving to the predator. 138 00:08:18,564 --> 00:08:20,566 And this has allowed us to get 139 00:08:20,566 --> 00:08:26,072 a better understanding of evolution. 140 00:08:29,075 --> 00:08:31,077 It's now abundantly clear 141 00:08:31,077 --> 00:08:33,079 that evolution is driven 142 00:08:33,079 --> 00:08:35,581 not just by physical forces 143 00:08:35,581 --> 00:08:40,586 such as storms and fire and climatic change 144 00:08:40,586 --> 00:08:46,092 but much more by biological forces. 145 00:08:46,092 --> 00:08:49,595 That is, particularly the way species interact 146 00:08:49,595 --> 00:08:51,097 with one another: 147 00:08:51,097 --> 00:08:55,101 cooperating with one another, parasitizing one another 148 00:08:55,101 --> 00:08:56,602 preying on one another. 149 00:09:00,106 --> 00:09:05,111 NARRATOR: What made the lion fierce and the zebra fast? 150 00:09:10,383 --> 00:09:14,887 What sparked the development of tooth and claw? 151 00:09:17,890 --> 00:09:23,896 The deadly dance of predator and prey drives evolution. 152 00:09:58,931 --> 00:10:01,934 Surely there was a time on an ancient savanna 153 00:10:01,934 --> 00:10:06,939 when hungry beasts hunted our ancestors. 154 00:10:06,939 --> 00:10:08,941 Perhaps the hot breath of carnivores 155 00:10:08,941 --> 00:10:10,943 once drove our own evolution 156 00:10:10,943 --> 00:10:15,448 and made us faster, stronger 157 00:10:15,448 --> 00:10:17,950 or smarter. 158 00:10:17,950 --> 00:10:22,955 But today, we have only one kind of predator left to fear. 159 00:10:24,957 --> 00:10:27,960 Microorganisms that cause disease 160 00:10:27,960 --> 00:10:31,464 consume us from the inside out. 161 00:10:31,464 --> 00:10:34,467 The human body is the food 162 00:10:34,467 --> 00:10:37,470 that fuels their rapid-fire reproduction. 163 00:10:37,470 --> 00:10:39,972 Some bacteria can reproduce 164 00:10:39,972 --> 00:10:44,477 a million times more quickly than we do. 165 00:10:44,477 --> 00:10:47,480 These microscopic predators have cast 166 00:10:47,480 --> 00:10:51,484 a long, dark shadow on our history. 167 00:10:55,988 --> 00:10:58,991 The bacteria that cause tuberculosis 168 00:10:58,991 --> 00:11:00,993 riddled the bodies of Egyptian nobles 169 00:11:00,993 --> 00:11:03,996 over 4,000 years ago. 170 00:11:06,499 --> 00:11:11,504 Another microbe spawned the dreaded Black Death. 171 00:11:11,504 --> 00:11:13,005 In the 14th century 172 00:11:13,005 --> 00:11:18,010 bubonic plague killed one in three Europeans. 173 00:11:20,012 --> 00:11:23,516 The influenza virus claimed some 20 million lives 174 00:11:23,516 --> 00:11:26,519 on the heels of World War I. 175 00:11:28,020 --> 00:11:32,024 We were virtually defenseless against infectious disease 176 00:11:32,024 --> 00:11:34,026 until recently. 177 00:11:40,533 --> 00:11:42,535 ANNOUNCER: This is a battlefield: 178 00:11:42,535 --> 00:11:46,038 a battlefield in man's total war against disease. 179 00:11:46,038 --> 00:11:49,542 Here, man has locked his heaviest artillery 180 00:11:49,542 --> 00:11:50,543 against premature death: 181 00:11:50,543 --> 00:11:56,549 antibiotics, the miracle drugs of our time. 182 00:12:00,052 --> 00:12:01,053 NARRATOR: In the 20th century 183 00:12:01,053 --> 00:12:05,057 scientists began to focus on the chemicals 184 00:12:05,057 --> 00:12:08,060 that microbes produce to attack each other. 185 00:12:10,062 --> 00:12:14,066 Perhaps some of these compounds would kill disease organisms 186 00:12:14,066 --> 00:12:16,569 without harming the human body. 187 00:12:18,571 --> 00:12:22,575 The first so-called antibiotic, penicillin 188 00:12:22,575 --> 00:12:26,078 saved countless lives in World War II. 189 00:12:26,078 --> 00:12:29,081 Now doctors had a weapon to fight the infections 190 00:12:29,081 --> 00:12:34,086 that commonly killed soldiers wounded on the battlefield. 191 00:12:34,086 --> 00:12:39,592 By the 1950s, hundreds of antibiotics were on the market. 192 00:12:39,592 --> 00:12:43,596 Defeating deadly germs seemed like child's play. 193 00:12:45,097 --> 00:12:49,602 In 1969, the U.S. Surgeon General declared 194 00:12:49,602 --> 00:12:54,607 it was "time to close the book on infectious disease." 195 00:12:54,607 --> 00:12:56,108 He spoke too soon. 196 00:13:06,118 --> 00:13:09,121 (men coughing and speaking softly) 197 00:13:09,121 --> 00:13:14,627 NARRATOR: The Russian prison system is ground zero of a new epidemic. 198 00:13:14,627 --> 00:13:19,131 An old killer is back with a vengeance. 199 00:13:19,632 --> 00:13:22,635 Since the collapse of the Soviet Union 200 00:13:22,635 --> 00:13:24,637 Russia's incarceration rate has soared 201 00:13:24,637 --> 00:13:27,139 to the highest in the world. 202 00:13:27,139 --> 00:13:30,643 More than one million inmates are confined to a penal system 203 00:13:30,643 --> 00:13:33,646 designed for a fraction of that number. 204 00:13:33,646 --> 00:13:39,151 But overcrowding, poor nutrition and scant sanitation 205 00:13:39,652 --> 00:13:43,155 are not the worst of a prisoner's nightmares. 206 00:13:43,155 --> 00:13:47,159 Now tuberculosis stalks these men. 207 00:13:50,663 --> 00:13:54,166 The bacteria that cause TB can lie dormant for decades 208 00:13:54,166 --> 00:13:56,669 in a healthy person. 209 00:13:56,669 --> 00:13:58,671 But if the immune system is weakened 210 00:13:59,171 --> 00:14:03,676 the microbes begin to multiply and consume the lungs. 211 00:14:06,679 --> 00:14:08,180 MAN: Prisoners are malnourished. 212 00:14:08,681 --> 00:14:09,682 Many of them are alcoholics. 213 00:14:09,682 --> 00:14:12,685 Many of them are smokers. 214 00:14:12,685 --> 00:14:15,187 And just the stress of being in prison 215 00:14:15,187 --> 00:14:18,190 all these factors together make you very, very susceptible 216 00:14:18,190 --> 00:14:21,193 to probably not only being infected with TB 217 00:14:21,193 --> 00:14:23,696 but also coming down with active disease. 218 00:14:23,696 --> 00:14:29,702 NARRATOR: When a person with active TB coughs or even speaks 219 00:14:29,702 --> 00:14:32,204 he expels contagious droplets 220 00:14:32,204 --> 00:14:35,207 that linger in the air for hours. 221 00:14:35,207 --> 00:14:40,212 The next victim needs only to inhale to be infected. 222 00:14:40,212 --> 00:14:45,217 At least 100,000 inmates have active TB 223 00:14:45,217 --> 00:14:48,721 but antibiotics are in short supply. 224 00:14:48,721 --> 00:14:53,225 Many men will die before their terms are up. 225 00:14:57,730 --> 00:15:00,232 Sasha Belevich is serving time 226 00:15:00,232 --> 00:15:04,236 for his second burglary conviction in Tomsk 227 00:15:04,236 --> 00:15:06,739 a city in western Siberia. 228 00:15:06,739 --> 00:15:10,743 His four-year term now seems like a death sentence. 229 00:15:12,244 --> 00:15:14,246 (Belevich speaking Russian) 230 00:15:14,246 --> 00:15:17,750 TRANSLATOR: I never thought I'd be infected. 231 00:15:17,750 --> 00:15:19,752 I never gave it much thought. 232 00:15:20,252 --> 00:15:24,757 At first, I didn't believe what the doctor told me. 233 00:15:24,757 --> 00:15:28,761 I thought that maybe it was any other illness 234 00:15:28,761 --> 00:15:30,763 but not tuberculosis. 235 00:15:30,763 --> 00:15:35,768 NARRATOR: Diagnosed during his first prison term 236 00:15:35,768 --> 00:15:37,269 Sasha was given antibiotics. 237 00:15:37,269 --> 00:15:39,271 He improved 238 00:15:39,271 --> 00:15:42,775 but after his release, he stopped getting treatment. 239 00:15:42,775 --> 00:15:48,280 Now his TB is back, but the same drugs cannot cure him. 240 00:15:48,280 --> 00:15:52,785 The microbes in his body have evolved. 241 00:15:54,787 --> 00:15:57,289 When Sasha first took antibiotics 242 00:15:57,289 --> 00:16:00,793 the drugs killed off most of the TB bacteria. 243 00:16:00,793 --> 00:16:05,297 But when his treatment stopped, it left some microbes alive, 244 00:16:05,297 --> 00:16:08,801 the ones that were most resistant to the drugs. 245 00:16:09,301 --> 00:16:11,303 As these survivors multiplied 246 00:16:11,303 --> 00:16:15,808 all their offspring acquired that same resistance. 247 00:16:15,808 --> 00:16:20,312 An entirely new strain of bacteria evolved 248 00:16:20,312 --> 00:16:23,816 untreatable with standard drugs. 249 00:16:23,816 --> 00:16:25,317 (man speaking Russian) 250 00:16:25,317 --> 00:16:30,322 NARRATOR: Sasha is now beyond help by prison doctors. 251 00:16:30,823 --> 00:16:32,825 He's not alone. 252 00:16:32,825 --> 00:16:38,831 At least 30,000 Russian inmates have multi-drug-resistant TB 253 00:16:38,831 --> 00:16:41,834 and their numbers are growing. 254 00:16:45,337 --> 00:16:49,341 This epidemic has brought Alex Goldfarb from New York 255 00:16:49,341 --> 00:16:50,843 back to his homeland. 256 00:16:56,348 --> 00:16:58,851 Working with Russian authorities 257 00:16:58,851 --> 00:17:02,354 he's developing a pilot program in the Tomsk prison 258 00:17:02,354 --> 00:17:04,857 to change the way TB is treated. 259 00:17:04,857 --> 00:17:09,862 GOLDFARB: This prison system is the ideal incubator 260 00:17:09,862 --> 00:17:13,365 for those drug-resistant strains. 261 00:17:13,365 --> 00:17:18,370 Russians have been using inadequate treatment regimens. 262 00:17:18,370 --> 00:17:22,374 Particularly in prisons, for the past decade 263 00:17:22,374 --> 00:17:24,877 they use a low quality drug 264 00:17:24,877 --> 00:17:30,382 they never finish the treatment course, and as the result 265 00:17:30,382 --> 00:17:33,385 these resistant strains are spreading on their own 266 00:17:33,385 --> 00:17:36,889 through coughing, and that's a major problem. 267 00:17:39,892 --> 00:17:41,894 NARRATOR: For drug-resistant cases 268 00:17:41,894 --> 00:17:46,398 Goldfarb has a small supply of so-called "second-line drugs." 269 00:17:46,398 --> 00:17:50,903 Far more expensive than standard TB treatments 270 00:17:51,403 --> 00:17:54,907 second-line drugs can cause dangerous side effects. 271 00:17:57,910 --> 00:17:59,912 But Goldfarb's supply 272 00:17:59,912 --> 00:18:03,415 won't even begin to cover 300 inmates quarantined 273 00:18:03,415 --> 00:18:05,417 in the drug resistance ward 274 00:18:05,417 --> 00:18:10,923 much less all the cases just outside prison walls. 275 00:18:13,425 --> 00:18:15,427 When a prisoner's term is up 276 00:18:15,427 --> 00:18:18,931 he's released into the heart of Tomsk; 277 00:18:18,931 --> 00:18:21,967 population: half a million. 278 00:18:21,967 --> 00:18:25,971 Healthy or sick, he's now free to walk these streets 279 00:18:25,971 --> 00:18:30,976 and ride these buses with unsuspecting citizens. 280 00:18:33,979 --> 00:18:35,981 (young woman speaking Russian) 281 00:18:35,981 --> 00:18:40,486 TRANSLATOR: Like any medical student, I knew about the disease. 282 00:18:40,486 --> 00:18:41,987 I knew its symptoms. 283 00:18:41,987 --> 00:18:46,992 But I had no idea it could be like this. 284 00:18:46,992 --> 00:18:51,997 NARRATOR: Anna Kolosova doesn't know how she became infected 285 00:18:51,997 --> 00:18:56,001 with a strain of TB resistant to five drugs. 286 00:18:56,001 --> 00:18:57,503 (speaking Russian) 287 00:18:57,503 --> 00:19:00,005 TRANSLATOR: I found out completely by accident. 288 00:19:00,005 --> 00:19:02,007 I went to take my driving test 289 00:19:02,007 --> 00:19:04,009 and I had to have a medical exam. 290 00:19:04,009 --> 00:19:07,513 They took an X ray and they told me I had tuberculosis. 291 00:19:09,515 --> 00:19:13,018 NARRATOR: Six months later, she began coughing up blood. 292 00:19:13,018 --> 00:19:15,521 On leave from medical school 293 00:19:15,521 --> 00:19:19,024 she has been hospitalized ever since. 294 00:19:19,024 --> 00:19:21,527 (speaking Russian) 295 00:19:21,527 --> 00:19:24,530 TRANSLATOR: If we had second-line drugs 296 00:19:24,530 --> 00:19:27,032 Anna's prognosis might be positive. 297 00:19:27,032 --> 00:19:32,037 Without them, her prognosis is not positive in the least. 298 00:19:33,539 --> 00:19:35,541 Anna's case is not unique. 299 00:19:35,541 --> 00:19:39,044 In my care, I have another college student 300 00:19:39,044 --> 00:19:42,548 and other young patients with drug-resistant TB. 301 00:19:44,049 --> 00:19:47,052 NARRATOR: Their symptoms can be eased. 302 00:19:47,052 --> 00:19:50,055 Their active disease may subside for a time. 303 00:19:50,556 --> 00:19:54,059 But the drugs that could save their lives 304 00:19:54,059 --> 00:19:56,562 are not yet within reach. 305 00:19:56,562 --> 00:19:59,064 (speaking Russian) 306 00:19:59,064 --> 00:20:04,570 NARRATOR: For now, just 30 inmates will receive second-line drugs. 307 00:20:04,570 --> 00:20:08,073 All have at least two more years to serve, 308 00:20:08,073 --> 00:20:11,577 a guarantee they'll complete their treatment 309 00:20:11,577 --> 00:20:16,081 and prevent the evolution of new drug-resistant bacteria. 310 00:20:16,081 --> 00:20:18,083 Still, there's grumbling. 311 00:20:18,083 --> 00:20:24,089 GOLDFARB: People are asking why you are spending $5,000 to $8,000 312 00:20:24,089 --> 00:20:27,593 to cure or treat a convicted killer. 313 00:20:27,593 --> 00:20:31,096 So we have to explain and explain and explain 314 00:20:31,096 --> 00:20:34,600 that we chose prisons for epidemiological reasons. 315 00:20:34,600 --> 00:20:38,604 This is the hub where this problem can be addressed. 316 00:20:38,604 --> 00:20:40,105 (speaking Russian) 317 00:20:40,105 --> 00:20:44,610 NARRATOR: A gesture of good faith, Goldfarb has removed his mask 318 00:20:44,610 --> 00:20:48,614 to address 30 men who are getting a second chance at life. 319 00:20:48,614 --> 00:20:50,115 He tells them 320 00:20:50,115 --> 00:20:54,119 "The treatment we're offering you is no experiment. 321 00:20:54,119 --> 00:20:56,121 "It has never been used in Russia 322 00:20:56,121 --> 00:20:58,624 "because it's too expensive. 323 00:20:58,624 --> 00:21:02,127 "It's a complicated and painful process. 324 00:21:02,127 --> 00:21:05,130 "For some of you, it will last a year and a half. 325 00:21:05,130 --> 00:21:10,135 "But all of you must take this as seriously as possible 326 00:21:10,135 --> 00:21:14,139 and complete the entire course of your treatment." 327 00:21:14,139 --> 00:21:15,641 Belevich! 328 00:21:16,642 --> 00:21:20,646 NARRATOR: Sasha was a victim of evolution 329 00:21:20,646 --> 00:21:24,149 but now the odds are good he'll live out his sentence. 330 00:21:24,149 --> 00:21:26,151 (Belevich speaking Russian) 331 00:21:26,151 --> 00:21:30,155 TRANSLATOR: I've got 2� years left to serve. 332 00:21:30,155 --> 00:21:32,658 I'm not afraid of the side effects. 333 00:21:32,658 --> 00:21:36,161 I just want to get better, that's all. 334 00:21:39,665 --> 00:21:43,669 NARRATOR: But in a facility for TB patients on the edge of town 335 00:21:43,669 --> 00:21:47,172 others remain prisoners of the disease. 336 00:21:48,674 --> 00:21:50,676 (Kolosova speaking Russian) 337 00:21:50,676 --> 00:21:53,679 TRANSLATOR: The new drugs are the only hope we have. 338 00:21:53,679 --> 00:21:56,682 There's nothing else to wait for. 339 00:21:56,682 --> 00:21:59,184 It's the only thing I'm waiting for. 340 00:21:59,685 --> 00:22:01,687 My family is very supportive. 341 00:22:01,687 --> 00:22:04,189 They visit every other day, 342 00:22:04,189 --> 00:22:07,693 my mother and father, my grandparents. 343 00:22:09,695 --> 00:22:12,197 I'm only 19. 344 00:22:12,197 --> 00:22:14,700 I have to be optimistic. 345 00:22:19,705 --> 00:22:23,709 NARRATOR: Siberia once seemed the most remote spot on Earth. 346 00:22:24,209 --> 00:22:26,211 Not anymore. 347 00:22:29,715 --> 00:22:34,720 Planes, trains and highways now crisscross Russia. 348 00:22:34,720 --> 00:22:37,723 Strains of drug-resistant TB have spread 349 00:22:37,723 --> 00:22:39,725 to thousands of citizens 350 00:22:40,225 --> 00:22:43,228 and some are leaving the country. 351 00:22:54,740 --> 00:22:58,243 KREISWIRTH: What's dramatically affected the spread of TB is 352 00:22:58,243 --> 00:22:59,745 our ability to travel. 353 00:22:59,745 --> 00:23:03,248 All the strains that are in the Russian prisons among prisoners 354 00:23:03,248 --> 00:23:05,751 will eventually come to our doorstep. 355 00:23:05,751 --> 00:23:11,256 NARRATOR: The global spread of TB is monitored in New York City 356 00:23:11,256 --> 00:23:14,760 at the Public Health Research Institute. 357 00:23:17,763 --> 00:23:23,268 On the rise nearly everywhere, TB now rivals AIDS: 358 00:23:23,268 --> 00:23:27,773 it claims two to three million lives a year. 359 00:23:27,773 --> 00:23:30,275 TB bacteria collected worldwide 360 00:23:30,275 --> 00:23:34,780 help researchers chart the evolution of new strains. 361 00:23:35,781 --> 00:23:38,283 DNA extracted from the bacteria 362 00:23:38,283 --> 00:23:41,787 can be displayed in a bar code pattern, 363 00:23:41,787 --> 00:23:46,792 a genetic fingerprint of the enemy, for Barry Kreiswirth. 364 00:23:46,792 --> 00:23:51,296 KREISWIRTH: We've been able to look literally at the DNA 365 00:23:51,797 --> 00:23:53,298 from the bacteria 366 00:23:53,298 --> 00:23:55,801 and we use this as a detective story. 367 00:23:55,801 --> 00:23:57,803 We can go from bacteria to bacteria 368 00:23:57,803 --> 00:23:59,304 which infect different people 369 00:23:59,304 --> 00:24:01,306 and ask, are these bacteria the same? 370 00:24:01,306 --> 00:24:02,808 Are we getting one person 371 00:24:03,308 --> 00:24:06,311 who is spreading his or her strain to many others? 372 00:24:07,813 --> 00:24:10,315 Based on our fingerprint database 373 00:24:10,315 --> 00:24:12,818 we've actually seen the most prominent strain 374 00:24:12,818 --> 00:24:15,821 that is running rampant throughout the Tomsk prison 375 00:24:15,821 --> 00:24:17,322 already in the U.S. 376 00:24:18,824 --> 00:24:21,827 Hi, Barry, what's up? 377 00:24:22,327 --> 00:24:23,829 Look at this. 378 00:24:23,829 --> 00:24:27,833 NARRATOR: Kreiswirth shares this grim discovery with Alex Goldfarb. 379 00:24:27,833 --> 00:24:30,335 So this is a fingerprint of that 148 strain 380 00:24:30,335 --> 00:24:32,838 that we see all over the Tomsk prisons, 381 00:24:32,838 --> 00:24:35,340 that multi-drug- resistant strain. 382 00:24:35,340 --> 00:24:39,845 Look at this one: same exact pattern. 383 00:24:39,845 --> 00:24:41,847 But this isn't from the prison; 384 00:24:41,847 --> 00:24:43,849 this is from a New York patient 385 00:24:43,849 --> 00:24:47,352 we received from the Department of Health in New York City. 386 00:24:47,352 --> 00:24:48,353 It's identical. 387 00:24:48,353 --> 00:24:49,354 Is he a Russian? 388 00:24:49,354 --> 00:24:50,856 Well, this is a Russian 389 00:24:50,856 --> 00:24:52,357 who has MDR-TB. 390 00:24:52,357 --> 00:24:54,359 So I think it's a nice find 391 00:24:54,359 --> 00:24:56,361 but it's a scary one, too. 392 00:25:00,866 --> 00:25:05,871 NARRATOR: How long before another traveler carries drug-resistant TB 393 00:25:05,871 --> 00:25:08,373 to New York or any other city? 394 00:25:08,373 --> 00:25:12,878 How long before others are infected? 395 00:25:12,878 --> 00:25:14,880 If an epidemic erupted 396 00:25:14,880 --> 00:25:18,884 most cities would be caught unprepared: 397 00:25:19,384 --> 00:25:22,888 not enough personnel trained to diagnose and treat TB; 398 00:25:22,888 --> 00:25:27,392 no stockpiles of second-line drugs; 399 00:25:27,893 --> 00:25:30,395 and TB is just the tip of the iceberg. 400 00:25:30,896 --> 00:25:35,901 The microbes that cause malaria, pneumonia, gonorrhea 401 00:25:35,901 --> 00:25:39,905 and scores of other infectious diseases 402 00:25:39,905 --> 00:25:43,408 are also evolving drug resistance. 403 00:25:43,408 --> 00:25:47,412 Misuse of antibiotics is one cause. 404 00:25:47,412 --> 00:25:49,915 Overuse is another. 405 00:25:49,915 --> 00:25:54,419 In the United States, nearly half of all prescriptions 406 00:25:54,419 --> 00:25:56,922 are unnecessary or inappropriate. 407 00:25:58,924 --> 00:26:01,426 KREISWIRTH: We've created this problem. 408 00:26:01,426 --> 00:26:04,429 Multi-drug resistance is a manmade problem. 409 00:26:04,429 --> 00:26:07,933 And we do that by putting antibiotics in animal feeds 410 00:26:07,933 --> 00:26:11,436 we have antibiotics running rampantly through hospitals 411 00:26:11,436 --> 00:26:13,939 we have antibiotics in the environment. 412 00:26:13,939 --> 00:26:16,942 By developing as many antibiotics that we have 413 00:26:16,942 --> 00:26:17,943 over the last 50 years 414 00:26:17,943 --> 00:26:21,446 we've essentially accelerated an evolutionary process. 415 00:26:21,446 --> 00:26:23,448 The outcome is 416 00:26:23,448 --> 00:26:27,452 that we're going to have more drug-resistant microbes 417 00:26:27,452 --> 00:26:31,456 to the point where some of the most dangerous bacteria 418 00:26:31,456 --> 00:26:32,958 will not be treatable. 419 00:26:34,459 --> 00:26:38,964 We're racing against the microbe every day 420 00:26:38,964 --> 00:26:41,967 and unfortunately we're losing. 421 00:26:41,967 --> 00:26:44,970 NARRATOR: It's an arms race without end. 422 00:26:44,970 --> 00:26:47,472 The more drugs we launch at microbes 423 00:26:47,472 --> 00:26:50,475 the more resistance they evolve. 424 00:26:50,475 --> 00:26:54,479 Maybe it's time to change our strategy. 425 00:27:00,485 --> 00:27:04,489 If we can drive microbes to evolve drug resistance 426 00:27:04,489 --> 00:27:08,493 then we can also make them evolve in ways that benefit us. 427 00:27:08,493 --> 00:27:16,034 This is the radical proposition of Amherst biologist Paul Ewald. 428 00:27:16,034 --> 00:27:17,535 EWALD: When people are looking 429 00:27:17,535 --> 00:27:19,537 at the antibiotic resistance problem 430 00:27:19,537 --> 00:27:22,540 they see evolution as sort of the... the bad guy. 431 00:27:22,540 --> 00:27:24,542 It's the evolutionary process 432 00:27:24,542 --> 00:27:27,545 that's led to antibiotic resistance and that's true. 433 00:27:27,545 --> 00:27:32,550 But, just as easily, we can have evolution being the solution. 434 00:27:32,550 --> 00:27:36,554 In other words, we can have evolutionary processes 435 00:27:36,554 --> 00:27:40,058 leading to organisms becoming more mild. 436 00:27:43,561 --> 00:27:47,065 NARRATOR: Disease organisms evolve to be more or less harmful 437 00:27:47,065 --> 00:27:51,069 depending on how they are spread. 438 00:27:51,069 --> 00:27:55,573 Microbes that depend on close contact between people 439 00:27:55,573 --> 00:27:57,575 tend to be mild. 440 00:27:57,575 --> 00:28:00,578 EWALD: The rhinovirus that causes a common cold 441 00:28:00,578 --> 00:28:02,580 is transmitted by people walking around 442 00:28:02,580 --> 00:28:05,083 sneezing or coughing on other people. 443 00:28:05,083 --> 00:28:09,587 Since it really does depend on fairly healthy people 444 00:28:09,587 --> 00:28:11,589 to be transmitted 445 00:28:11,589 --> 00:28:15,593 not surprisingly, it's one of the mildest viruses 446 00:28:15,593 --> 00:28:17,595 that we know about. 447 00:28:19,097 --> 00:28:22,600 NARRATOR: But microbes that are transmitted by insects 448 00:28:22,600 --> 00:28:25,103 or by tainted food or water 449 00:28:25,103 --> 00:28:28,106 tend to make people very sick. 450 00:28:28,106 --> 00:28:30,608 EWALD: The worst of all of the diarrheal bacteria 451 00:28:30,608 --> 00:28:33,111 that we know of have been waterborne. 452 00:28:33,111 --> 00:28:37,615 The bacteria that cause cholera and typhoid fever 453 00:28:37,615 --> 00:28:39,117 are often waterborne. 454 00:28:39,117 --> 00:28:42,120 So even if the organism is so harmful 455 00:28:42,120 --> 00:28:44,622 that the sick person can't move from bed 456 00:28:44,622 --> 00:28:46,124 the organism can still be transmitted 457 00:28:46,124 --> 00:28:48,626 to large numbers of people. 458 00:28:52,130 --> 00:28:54,632 Once we understand the factors 459 00:28:54,632 --> 00:28:59,137 that favor increased harmfulness and decreased harmfulness 460 00:28:59,137 --> 00:29:02,140 then we can look at all of the things we do in society 461 00:29:02,140 --> 00:29:05,143 and we can ask the question: Are we doing certain things 462 00:29:05,143 --> 00:29:07,145 or can we do certain things 463 00:29:07,145 --> 00:29:11,149 that would favor organisms evolving towards mildness? 464 00:29:13,151 --> 00:29:16,654 We can look at the cholera outbreak in South America 465 00:29:16,654 --> 00:29:19,157 as a kind of natural experiment 466 00:29:19,657 --> 00:29:21,159 that allows us to evaluate these ideas. 467 00:29:22,660 --> 00:29:28,666 NARRATOR: In 1991, cholera invaded Peru and spread quickly. 468 00:29:28,666 --> 00:29:32,670 Over the next five years, more than one million people 469 00:29:32,670 --> 00:29:37,675 were stricken with diarrhea and vomiting, some severely. 470 00:29:38,676 --> 00:29:42,180 Over 10,000 people died. 471 00:29:47,185 --> 00:29:49,187 The disease was transmitted through water 472 00:29:49,187 --> 00:29:51,189 contaminated with human waste 473 00:29:51,189 --> 00:29:55,693 or through food that was washed or handled by infected people. 474 00:29:58,196 --> 00:30:01,199 Ewald collected strains of cholera bacteria 475 00:30:01,199 --> 00:30:03,201 from South America 476 00:30:03,201 --> 00:30:06,204 and measured the amount of toxin they produced, 477 00:30:06,204 --> 00:30:10,208 an indication of their virulence. 478 00:30:10,208 --> 00:30:14,712 Over time, he would document evolution in action. 479 00:30:17,715 --> 00:30:22,220 EWALD: If you have contaminated water, allowing transmission 480 00:30:22,720 --> 00:30:23,721 we expect the cholera organism 481 00:30:24,222 --> 00:30:27,725 to evolve to a particularly high level of harmfulness 482 00:30:27,725 --> 00:30:29,227 and that's exactly what we see. 483 00:30:30,728 --> 00:30:32,230 We find that the bacteria 484 00:30:32,230 --> 00:30:35,733 that had invaded countries with poor water supplies 485 00:30:35,733 --> 00:30:38,236 evolved increased harmfulness over time; 486 00:30:38,236 --> 00:30:41,239 they've actually become more toxigenic, 487 00:30:41,239 --> 00:30:44,242 they produce more toxin than they did at the outset. 488 00:30:45,743 --> 00:30:49,247 If, instead, we clean up the water supplies 489 00:30:49,247 --> 00:30:51,749 then we force the bacteria to be transmitted 490 00:30:51,749 --> 00:30:56,754 only by routes that require healthy people. 491 00:30:56,754 --> 00:30:59,757 And what we find is 492 00:30:59,757 --> 00:31:01,259 that when cholera invaded 493 00:31:01,259 --> 00:31:03,261 countries with clean water supplies 494 00:31:03,261 --> 00:31:06,764 the organism dropped in its harmfulness. 495 00:31:07,265 --> 00:31:10,268 Those bacteria evolved lower levels of toxin production; 496 00:31:10,268 --> 00:31:13,271 they actually became more mild through time. 497 00:31:14,272 --> 00:31:16,274 People would still be getting infected 498 00:31:16,274 --> 00:31:17,775 but the infections would be so mild 499 00:31:17,775 --> 00:31:21,779 that most people won't even be sick. 500 00:31:21,779 --> 00:31:24,782 So, the cholera outbreak in Latin America suggests 501 00:31:24,782 --> 00:31:27,285 that we may need only a few years 502 00:31:27,785 --> 00:31:29,787 to change the cholera organism 503 00:31:29,787 --> 00:31:32,290 from one that would often kill people 504 00:31:32,290 --> 00:31:35,793 to one that hardly ever causes the disease. 505 00:31:38,296 --> 00:31:39,797 What we're suggesting here 506 00:31:39,797 --> 00:31:42,300 is that we can domesticate these disease organisms, 507 00:31:42,300 --> 00:31:43,801 very much in the same way 508 00:31:43,801 --> 00:31:45,803 that we have domesticated other organisms 509 00:31:45,803 --> 00:31:47,305 that are potentially harmful. 510 00:31:49,807 --> 00:31:52,810 For example, wolves have been harmful to us 511 00:31:52,810 --> 00:31:54,812 throughout our evolutionary history 512 00:31:54,812 --> 00:31:56,314 but through domestication 513 00:31:56,314 --> 00:31:59,317 some wolves have evolved into dogs 514 00:31:59,317 --> 00:32:02,320 that instead of harming us, actually help us. 515 00:32:02,320 --> 00:32:04,822 And I think we can do the same thing 516 00:32:04,822 --> 00:32:06,824 with these disease organisms. 517 00:32:08,326 --> 00:32:11,329 NARRATOR: Working with evolution instead of against it 518 00:32:11,329 --> 00:32:16,834 we might eventually subdue even the deadliest microbes. 519 00:32:16,834 --> 00:32:21,839 Evolution has already forged such surprising truces. 520 00:32:23,841 --> 00:32:25,343 WOMAN: Okay. 521 00:32:27,845 --> 00:32:31,849 NARRATOR: Most wild cats have evolved a way to live with a virus 522 00:32:32,350 --> 00:32:37,355 closely related to one that is decimating humans. 523 00:32:37,355 --> 00:32:41,359 The story was unraveled by Stephen O'Brien, 524 00:32:41,359 --> 00:32:46,364 here at the National Zoo to examine a tranquilized cheetah. 525 00:32:47,865 --> 00:32:50,368 Well, we originally became interested in the cats 526 00:32:50,368 --> 00:32:52,370 because I was interested in the interplay 527 00:32:52,870 --> 00:32:54,372 between infectious diseases 528 00:32:54,372 --> 00:32:56,374 and the genes of the species that suffer them. 529 00:32:56,374 --> 00:32:58,376 We began working with cheetahs 530 00:32:58,376 --> 00:33:00,878 and subsequently started to study 531 00:33:00,878 --> 00:33:05,383 each of the 37 different species in the cat family. 532 00:33:05,383 --> 00:33:08,886 What we're learning from them is that they are mirrors 533 00:33:08,886 --> 00:33:12,890 of evolutionary processes in humans. 534 00:33:12,890 --> 00:33:19,397 NARRATOR: It all began in the 1980s when O'Brien became concerned 535 00:33:19,397 --> 00:33:21,399 that small populations of endangered cats 536 00:33:21,399 --> 00:33:23,401 were especially vulnerable 537 00:33:23,401 --> 00:33:26,904 to the ravages of infectious disease. 538 00:33:29,407 --> 00:33:33,911 Then he heard that domestic cats were falling prey 539 00:33:33,911 --> 00:33:36,914 to a newly discovered and lethal virus: 540 00:33:36,914 --> 00:33:44,422 The Feline Immunodeficiency Virus, or F.I.V. 541 00:33:44,422 --> 00:33:48,426 F.I.V. is associated with very skinny and malnourished 542 00:33:48,426 --> 00:33:51,429 and wasting disease in house cats. 543 00:33:51,429 --> 00:33:53,431 And that disease was the result 544 00:33:53,431 --> 00:33:54,932 of the collapse of the immune system. 545 00:33:55,433 --> 00:33:57,935 So, the parallels with Human Immunodeficiency Virus 546 00:33:57,935 --> 00:33:59,937 were very strong. 547 00:33:59,937 --> 00:34:05,443 I was curious as to whether or not the virus had also been able 548 00:34:05,443 --> 00:34:07,945 to infect nondomestic cats. 549 00:34:07,945 --> 00:34:11,449 NARRATOR: O'Brien had collected biological specimens 550 00:34:11,449 --> 00:34:14,952 from thousands of wild cats around the world. 551 00:34:14,952 --> 00:34:18,956 He began to screen them for the presence of the virus. 552 00:34:21,459 --> 00:34:25,463 O'BRIEN: Well, when we did that in cheetahs from East Africa 553 00:34:25,463 --> 00:34:28,966 and the pumas in the Rockies 554 00:34:28,966 --> 00:34:30,968 and the ocelots down in the Andes 555 00:34:30,968 --> 00:34:33,471 and the lions in the Serengeti, it turned out 556 00:34:33,471 --> 00:34:36,974 that virtually every species of cats on the planet 557 00:34:36,974 --> 00:34:39,977 had been exposed to and infected 558 00:34:39,977 --> 00:34:43,981 with a version of Feline Immunodeficiency Virus. 559 00:34:46,484 --> 00:34:47,985 Well, I was terrified 560 00:34:47,985 --> 00:34:51,989 because I thought that we were just a heartbeat away 561 00:34:51,989 --> 00:34:54,992 from a epidemic that was going to decimate 562 00:34:54,992 --> 00:34:59,997 some of these cats and, since 36 of 37 of these cat species 563 00:34:59,997 --> 00:35:03,000 are already considered endangered or threatened 564 00:35:03,000 --> 00:35:05,002 then this could be the final wallop. 565 00:35:08,005 --> 00:35:11,008 NARRATOR: For years, O'Brien feared the worst. 566 00:35:11,008 --> 00:35:15,012 He urged zoo keepers and game wardens around the world 567 00:35:15,012 --> 00:35:18,516 to test their animals for the virus 568 00:35:18,516 --> 00:35:21,018 and to watch for AIDS-like symptoms. 569 00:35:23,020 --> 00:35:25,022 O'BRIEN: What we discovered, though, over time 570 00:35:25,022 --> 00:35:27,525 is that these cats were really not getting ill. 571 00:35:27,525 --> 00:35:32,029 It was as if they had somehow come up with a resistance 572 00:35:32,029 --> 00:35:34,031 to a fatal virus. 573 00:35:37,535 --> 00:35:39,036 NARRATOR: O'Brien's research suggests 574 00:35:39,036 --> 00:35:43,040 F.I.V. first infected the cats' ancestors 575 00:35:43,040 --> 00:35:46,043 around one million years ago. 576 00:35:46,043 --> 00:35:49,547 It decimated the animals 577 00:35:49,547 --> 00:35:53,551 but a few cats carried mutations 578 00:35:53,551 --> 00:35:58,055 that made them resistant to the virus. 579 00:35:58,055 --> 00:36:00,958 These survivors passed on their protective genes 580 00:36:00,958 --> 00:36:02,960 to their offspring 581 00:36:02,960 --> 00:36:05,963 and to most wild cats alive today. 582 00:36:05,963 --> 00:36:09,467 Over time, the virus may also have evolved 583 00:36:09,467 --> 00:36:12,970 into less lethal strains. 584 00:36:12,970 --> 00:36:16,974 Today, wild cats and F.I.V. have reached the end 585 00:36:16,974 --> 00:36:19,477 of a long evolutionary process 586 00:36:19,477 --> 00:36:21,979 and have adapted to each other. 587 00:36:24,982 --> 00:36:30,988 Humans and H.I.V. only recently embarked on the path 588 00:36:30,988 --> 00:36:35,993 that might eventually lead to a truce. 589 00:36:35,993 --> 00:36:38,996 But the example of the wild cats convinced O'Brien 590 00:36:38,996 --> 00:36:42,500 there must be people endowed with mutations 591 00:36:42,500 --> 00:36:46,504 that protect them from H.I.V. 592 00:36:46,504 --> 00:36:50,508 He set out to find them. 593 00:36:50,508 --> 00:36:52,510 O'BRIEN: Over a ten-year period of time 594 00:36:52,510 --> 00:36:55,012 I quietly collected blood samples 595 00:36:55,012 --> 00:36:59,517 from 10,000 individuals that are high risk. 596 00:36:59,517 --> 00:37:02,019 My colleagues and I extracted the DNA 597 00:37:02,019 --> 00:37:06,023 and we were stunned to discover a whopping mutation 598 00:37:06,023 --> 00:37:10,528 which protected against H.I.V. infection. 599 00:37:11,028 --> 00:37:15,032 And it was the first gene that we could definitively say 600 00:37:15,032 --> 00:37:20,037 was influencing the outcome of exposure to this deadly virus. 601 00:37:20,037 --> 00:37:24,542 NARRATOR: Most people have receptors on their immune cells 602 00:37:24,542 --> 00:37:29,046 that allow H.I.V. to dock and gain entry. 603 00:37:29,046 --> 00:37:32,550 But people with the mutation discovered by O'Brien 604 00:37:32,550 --> 00:37:35,553 lack some or all of these receptors. 605 00:37:35,553 --> 00:37:40,558 Infection by H.I.V. becomes impossible. 606 00:37:42,059 --> 00:37:44,061 The mutation is present 607 00:37:44,061 --> 00:37:47,064 in about ten percent of European Caucasians 608 00:37:47,064 --> 00:37:52,570 but completely absent in native African and East Asian peoples. 609 00:37:52,570 --> 00:37:56,574 Something in the evolutionary history of Caucasians 610 00:37:57,074 --> 00:38:01,078 must have favored the survival of people with this mutation. 611 00:38:03,080 --> 00:38:05,583 O'BRIEN: We've actually used precise dating techniques 612 00:38:05,583 --> 00:38:09,086 to date the last time such a selective pressure took place. 613 00:38:09,587 --> 00:38:12,590 And that came out 700 years ago. 614 00:38:12,590 --> 00:38:15,092 Well, if you look in the history books 615 00:38:15,092 --> 00:38:18,596 that was the time of a rather dramatic infectious disease 616 00:38:18,596 --> 00:38:22,600 a pandemic, which was the Black Death or the bubonic plague. 617 00:38:22,600 --> 00:38:26,604 And at that time, a third of Europeans were wiped out. 618 00:38:27,104 --> 00:38:30,107 NARRATOR: A mutation that saved people from the plague 619 00:38:30,107 --> 00:38:32,109 seven centuries ago 620 00:38:32,109 --> 00:38:34,111 may now protect their descendants 621 00:38:34,111 --> 00:38:38,115 from infection by H.I.V. 622 00:38:38,115 --> 00:38:42,119 O'BRIEN: Today, when we scroll through the genes of cats or humans 623 00:38:42,119 --> 00:38:44,121 we discover that they're littered 624 00:38:44,121 --> 00:38:46,624 with these footprints of historic epidemics 625 00:38:46,624 --> 00:38:51,629 that have defined the survival of today's living species. 626 00:38:57,134 --> 00:38:58,636 NARRATOR: We all bear the marks 627 00:38:58,636 --> 00:39:02,640 of our ancestors' struggle for survival 628 00:39:02,640 --> 00:39:07,645 but evolution is driven not just by conflict and competition. 629 00:39:07,645 --> 00:39:11,649 Cooperation and teamwork have also ensured 630 00:39:11,649 --> 00:39:15,653 the "survival of the fittest." 631 00:39:16,654 --> 00:39:19,156 Toward the end of the 20th century 632 00:39:19,156 --> 00:39:21,158 biologists began to realize 633 00:39:21,158 --> 00:39:24,161 that there's another force equally important 634 00:39:24,161 --> 00:39:27,665 and responsible for the buildup of a great deal 635 00:39:27,665 --> 00:39:30,167 of the magnificent superstructure 636 00:39:30,167 --> 00:39:32,169 of the Earth's biodiversity. 637 00:39:32,169 --> 00:39:36,173 And that is cooperation, what we call symbiosis, 638 00:39:36,173 --> 00:39:39,677 and, particularly, mutualistic symbiosis; 639 00:39:39,677 --> 00:39:42,179 that is, intimate living together 640 00:39:42,179 --> 00:39:44,181 of different kinds of organisms 641 00:39:44,181 --> 00:39:47,184 in which there's a partnership 642 00:39:47,184 --> 00:39:50,688 which benefits both of the partners. 643 00:39:52,189 --> 00:39:55,693 NARRATOR: Nature abounds in symbiosis. 644 00:39:55,693 --> 00:40:01,699 Many species depend on a partner for their very survival. 645 00:40:03,200 --> 00:40:05,703 A grouper enjoys a cleaning 646 00:40:05,703 --> 00:40:09,707 as tiny shrimp eat the parasites on its skin. 647 00:40:11,208 --> 00:40:14,211 Anemones give safe harbor to clownfish 648 00:40:14,211 --> 00:40:17,715 who bring food and chase off predators. 649 00:40:19,216 --> 00:40:22,720 With nectar and pollen, flowers entice birds and bees 650 00:40:22,720 --> 00:40:24,722 to help fertilize them. 651 00:40:28,726 --> 00:40:32,229 Most plants rely on fungi living on their roots 652 00:40:32,229 --> 00:40:36,734 to extract nutrients from the soil. 653 00:40:37,234 --> 00:40:40,237 And grazing animals could not digest their diet 654 00:40:40,237 --> 00:40:43,741 without the bacteria that live in their gut 655 00:40:43,741 --> 00:40:46,744 and break down plant matter. 656 00:40:48,245 --> 00:40:51,248 We, too, are symbiotic creatures. 657 00:40:51,248 --> 00:40:55,753 Beneficial bacteria cover every inch of our skin 658 00:40:55,753 --> 00:40:58,255 and the length of our intestines. 659 00:40:58,255 --> 00:41:01,258 They help digest food, produce vitamins 660 00:41:01,759 --> 00:41:04,762 and keep dangerous microbes out. 661 00:41:06,263 --> 00:41:10,267 (forest buzzing with insect and animal calls) 662 00:41:10,267 --> 00:41:16,774 Symbiosis has deep roots in the history of life. 663 00:41:16,774 --> 00:41:19,777 Some 50 to 60 million years ago 664 00:41:19,777 --> 00:41:22,780 just after the age of the dinosaurs 665 00:41:22,780 --> 00:41:27,284 two species formed a lasting bond here in the dense thicket 666 00:41:27,284 --> 00:41:30,788 that would become the Amazonian rain forest. 667 00:41:33,290 --> 00:41:36,293 MAN: A big mature Atta nest. 668 00:41:36,293 --> 00:41:39,296 NARRATOR: These huge mounds of earth are the product 669 00:41:39,296 --> 00:41:40,798 of that partnership, 670 00:41:40,798 --> 00:41:44,301 one that brought Ted Schultz and Ulrich Mueller 671 00:41:44,301 --> 00:41:48,305 to a remote corner of Brazil. 672 00:41:48,305 --> 00:41:54,311 The unlikely excavators of all this dirt are leaf-cutter ants. 673 00:41:56,814 --> 00:41:58,816 MAN: Look, they're bringing stuff in. 674 00:41:58,816 --> 00:42:00,317 There're some foragers here starting. 675 00:42:00,317 --> 00:42:01,819 Yeah... 676 00:42:01,819 --> 00:42:04,822 NARRATOR: Leaf-cutter ants make their nests 677 00:42:04,822 --> 00:42:06,824 in underground chambers. 678 00:42:06,824 --> 00:42:11,328 They emerge regularly to forage, blazing trails 679 00:42:11,328 --> 00:42:15,332 that extend hundreds of feet into the forest. 680 00:42:15,332 --> 00:42:19,837 Most tropical plants are permeated with toxic chemicals, 681 00:42:19,837 --> 00:42:23,340 a deterrent against browsers. 682 00:42:23,340 --> 00:42:27,845 The ants cut fresh vegetation, but they don't eat it. 683 00:42:27,845 --> 00:42:31,348 They feed it to another organism. 684 00:42:33,851 --> 00:42:37,354 Foragers carry their cargo down into the nest 685 00:42:37,354 --> 00:42:41,358 and turn it over to smaller worker ants. 686 00:42:41,358 --> 00:42:44,361 They clean the leaf fragments 687 00:42:44,361 --> 00:42:47,364 and chew them into a pulpy mulch. 688 00:42:47,364 --> 00:42:49,867 Leaf-cutters cultivate a fungus 689 00:42:49,867 --> 00:42:53,370 that breaks down the toxins in the leaves 690 00:42:53,370 --> 00:42:56,373 and swells with proteins and sugars. 691 00:42:56,373 --> 00:42:59,877 This is the ants' food. 692 00:42:59,877 --> 00:43:04,882 MUELLER: Both the ants and the cultivated fungus 693 00:43:04,882 --> 00:43:07,384 are dependent on each other for living. 694 00:43:07,384 --> 00:43:11,388 The ants need the fungus as a food, they're dependent on it; 695 00:43:11,388 --> 00:43:13,891 you take away the fungus, they will die. 696 00:43:13,891 --> 00:43:18,896 In reverse, the fungus cannot do without the ants. 697 00:43:18,896 --> 00:43:21,899 So, it's a mutual co-dependency. 698 00:43:21,899 --> 00:43:24,902 SCHULTZ: A mature colony of leaf-cutter ants can consist 699 00:43:24,902 --> 00:43:27,404 of as many as eight million individuals 700 00:43:27,404 --> 00:43:30,908 and they're the dominant herbivores 701 00:43:30,908 --> 00:43:33,911 of the New World tropics. 702 00:43:33,911 --> 00:43:39,917 They take an estimated 15% to 20% of all the fresh vegetation. 703 00:43:39,917 --> 00:43:42,419 A mature colony of Atta leaf-cutter ants 704 00:43:42,419 --> 00:43:44,421 are the equivalent of an adult cow 705 00:43:44,421 --> 00:43:46,924 sitting in the middle of the rain forest 706 00:43:46,924 --> 00:43:51,929 foraging on the vegetation in their immediate area. 707 00:43:57,935 --> 00:44:01,939 NARRATOR: The entire rain forest is affected by the symbiosis 708 00:44:01,939 --> 00:44:03,941 of ant and fungus. 709 00:44:03,941 --> 00:44:05,943 To understand how it evolved 710 00:44:05,943 --> 00:44:11,448 Schultz and Mueller collect ant nests throughout Latin America. 711 00:44:11,448 --> 00:44:12,950 Here's one. 712 00:44:12,950 --> 00:44:13,951 Where? 713 00:44:13,951 --> 00:44:15,953 Oh, yeah. 714 00:44:15,953 --> 00:44:19,957 NARRATOR: An experienced eye can spot the subtle signs of a young nest 715 00:44:19,957 --> 00:44:22,960 founded perhaps six months ago 716 00:44:22,960 --> 00:44:27,464 when a new queen left home with a bit of fungus in her mouth 717 00:44:27,464 --> 00:44:29,466 and burrowed into the ground. 718 00:44:30,467 --> 00:44:32,970 BOTH: There it is. 719 00:44:32,970 --> 00:44:34,972 SCHULTZ: Beautiful. 720 00:44:34,972 --> 00:44:37,975 MUELLER: Opening a nest is a very exciting moment. 721 00:44:38,475 --> 00:44:41,979 Suddenly, the cavity opens and you see the fungus garden 722 00:44:41,979 --> 00:44:44,481 and then you may see the queen. 723 00:44:44,982 --> 00:44:46,483 SCHULTZ: There's the queen. 724 00:44:46,483 --> 00:44:48,485 MUELLER: Yes, there she is. 725 00:44:48,485 --> 00:44:50,487 The size of a peanut. 726 00:44:50,487 --> 00:44:53,991 MUELLER: What we've learned from studying the ants 727 00:44:53,991 --> 00:44:56,994 is that you can have a long-term existence, 728 00:44:56,994 --> 00:45:00,397 over 50 million years as an agriculturist. 729 00:45:00,397 --> 00:45:03,400 There's clear parallels between the ant agriculture 730 00:45:03,400 --> 00:45:05,402 and the human agriculture. 731 00:45:05,402 --> 00:45:07,404 Both types of societies are dependent 732 00:45:07,404 --> 00:45:09,907 on cultivation of some other organism 733 00:45:09,907 --> 00:45:11,909 and have very sophisticated procedures 734 00:45:11,909 --> 00:45:14,411 how to promote the growth of these organisms. 735 00:45:16,413 --> 00:45:20,417 NARRATOR: But human farmers are plagued by pests in their crops 736 00:45:20,417 --> 00:45:24,421 while the ants' gardens seemed pest-free. 737 00:45:24,421 --> 00:45:26,924 A century of research had concluded 738 00:45:26,924 --> 00:45:29,426 that the ants are probably so adept at weeding 739 00:45:29,426 --> 00:45:33,430 that no infestation can take hold. 740 00:45:33,430 --> 00:45:36,433 A graduate student in 1998 741 00:45:36,433 --> 00:45:39,937 Cameron Currie just didn't buy it. 742 00:45:39,937 --> 00:45:41,939 I actually had some people tell me 743 00:45:41,939 --> 00:45:44,441 that looking at diseases in the ant gardens 744 00:45:44,441 --> 00:45:46,443 was kind of a silly project, 745 00:45:46,443 --> 00:45:48,946 that the ants maintained their gardens free of diseases 746 00:45:48,946 --> 00:45:53,450 and so why would you be going there to look for diseases? 747 00:45:53,450 --> 00:45:56,453 So I went out and collected ant colonies 748 00:45:56,453 --> 00:45:58,455 and then I isolated pieces of the garden 749 00:45:58,455 --> 00:46:01,458 to see what was there other than the fungus the ants cultivated. 750 00:46:01,458 --> 00:46:06,463 NARRATOR: He cultured 1,500 fungus samples 751 00:46:06,463 --> 00:46:09,466 and the same aggressive mold kept showing up. 752 00:46:11,468 --> 00:46:13,971 When he removed the ants from a nest 753 00:46:13,971 --> 00:46:17,975 he saw the mold devastate the fungus in a matter of days. 754 00:46:17,975 --> 00:46:22,479 So the antsdidhave a pest in their gardens. 755 00:46:22,479 --> 00:46:25,482 But how did they keep it so completely under control? 756 00:46:28,485 --> 00:46:32,489 Cameron began to wonder about a white, waxy coating 757 00:46:32,489 --> 00:46:34,491 on the body parts of some ants. 758 00:46:34,491 --> 00:46:35,993 What really intrigued him 759 00:46:35,993 --> 00:46:38,996 were the ants working deep in the gardens 760 00:46:38,996 --> 00:46:41,999 that were covered with the stuff. 761 00:46:41,999 --> 00:46:44,001 He asked the experts about it. 762 00:46:44,001 --> 00:46:46,503 SCHULTZ: In the past 763 00:46:46,503 --> 00:46:48,505 people had just considered this to be 764 00:46:48,505 --> 00:46:50,507 some sort of nondescript secretion 765 00:46:50,507 --> 00:46:52,509 that was produced by the ants 766 00:46:52,509 --> 00:46:55,012 for unknown, probably uninteresting reasons. 767 00:46:55,012 --> 00:46:57,014 And Cameron was the first 768 00:46:57,014 --> 00:47:00,017 to put this waxy secretion under the microscope 769 00:47:00,017 --> 00:47:02,019 and notice it was not inert and lifeless 770 00:47:02,519 --> 00:47:04,521 but it was actually alive. 771 00:47:04,521 --> 00:47:11,028 NARRATOR: The "wax" turned out to be tangled mats of bacteria. 772 00:47:11,028 --> 00:47:12,529 But what shocked Cameron 773 00:47:13,030 --> 00:47:16,033 was these were the same types of bacteria 774 00:47:16,033 --> 00:47:18,535 that produce half the antibiotics 775 00:47:18,535 --> 00:47:21,538 used in human medicine. 776 00:47:21,538 --> 00:47:24,541 CURRIE: I remember my graduate advisor and I were laughing 777 00:47:24,541 --> 00:47:27,044 thinking that wouldn't this be exciting 778 00:47:27,044 --> 00:47:30,547 if these ants had been effectively using these bacteria 779 00:47:30,547 --> 00:47:34,051 for production of antibiotics for millions of years 780 00:47:34,051 --> 00:47:36,553 when humans only discovered this 60 years ago. 781 00:47:36,553 --> 00:47:38,055 And we thought at the time 782 00:47:38,055 --> 00:47:40,057 that this was maybe a bit farfetched. 783 00:47:40,057 --> 00:47:43,060 NARRATOR: Farfetched but true. 784 00:47:43,060 --> 00:47:46,063 It seems the ants have been using antibiotics 785 00:47:46,063 --> 00:47:49,066 to control the pest in their gardens 786 00:47:49,066 --> 00:47:51,568 for some 50 million years. 787 00:47:51,568 --> 00:47:55,572 So why hasn't the mold evolved antibiotic resistance? 788 00:47:57,074 --> 00:48:00,077 SCHULTZ: I think that the answer probably lies 789 00:48:00,077 --> 00:48:03,080 in the fact that the ants are using cultures 790 00:48:03,080 --> 00:48:09,086 of millions of cells of bacteria to produce these antibiotics. 791 00:48:09,086 --> 00:48:11,588 And so these bacteria are evolving. 792 00:48:11,588 --> 00:48:16,593 Likewise the pathogen that is the target of these antibiotics 793 00:48:16,593 --> 00:48:20,597 is also evolving, and it's an evolutionary arms race 794 00:48:20,597 --> 00:48:24,601 that has continued for 50 million years. 795 00:48:28,605 --> 00:48:33,610 NARRATOR: And so the symbiosis of ant and fungus also includes 796 00:48:33,610 --> 00:48:36,113 the aggressive mold in the fungus garden 797 00:48:36,113 --> 00:48:38,615 and the bacteria living on the ants. 798 00:48:38,615 --> 00:48:43,120 Nature is often more complex than it first appears. 799 00:48:44,621 --> 00:48:47,124 WILSON: Scientists have just begun to understand 800 00:48:47,124 --> 00:48:51,128 how two species can interact, or three or four. 801 00:48:51,128 --> 00:48:54,131 But they're a long way from understanding 802 00:48:54,131 --> 00:48:57,634 how thousands, or tens of thousands of species 803 00:48:57,634 --> 00:49:02,639 can interact to create the monumental ecosystems 804 00:49:02,639 --> 00:49:07,144 of the world, like rain forests and coral reefs. 805 00:49:07,144 --> 00:49:14,651 And the most remarkable gap in our knowledge is in bacteria 806 00:49:14,651 --> 00:49:17,654 and other microorganisms 807 00:49:17,654 --> 00:49:21,658 because these make up the base of the living world. 808 00:49:21,658 --> 00:49:25,662 We need them; they don't need us. 809 00:49:28,665 --> 00:49:33,670 NARRATOR: And yet we do everything in our power to avoid microbes. 810 00:49:35,672 --> 00:49:40,677 A barrage of new products states the message loud and clear: 811 00:49:40,677 --> 00:49:44,681 The only good germ is a dead one. 812 00:49:51,688 --> 00:49:54,691 Are we making our world too clean? 813 00:49:54,691 --> 00:50:00,197 Consider the research of pediatrician Erika von Mutius. 814 00:50:00,197 --> 00:50:01,698 Du musst feste einatmen, bitte. 815 00:50:01,698 --> 00:50:04,201 Stelltest richtig fest... 816 00:50:04,201 --> 00:50:05,702 Gut, noch mal. 817 00:50:05,702 --> 00:50:08,205 NARRATOR: She treats allergies and asthma, 818 00:50:08,205 --> 00:50:11,708 conditions in which the immune system overreacts 819 00:50:11,708 --> 00:50:13,210 to harmless substances. 820 00:50:13,210 --> 00:50:16,713 Rates of both disorders are on the rise 821 00:50:16,713 --> 00:50:19,716 in affluent, industrialized regions. 822 00:50:21,718 --> 00:50:24,721 Perhaps children are growing up in surroundings 823 00:50:24,721 --> 00:50:27,224 too germ-free for their own good. 824 00:50:29,226 --> 00:50:31,228 VON MUTIUS: Microbes do 825 00:50:31,228 --> 00:50:33,230 a lot of harmful things to us 826 00:50:33,230 --> 00:50:36,733 but they may also be important for our immune system 827 00:50:36,733 --> 00:50:39,736 to learn how to deal with the environment 828 00:50:39,736 --> 00:50:42,739 and how to tolerate and fight 829 00:50:42,739 --> 00:50:44,741 viruses, bacteria and infections. 830 00:50:47,244 --> 00:50:50,747 NARRATOR: To understand the causes of allergies and asthma 831 00:50:50,747 --> 00:50:52,749 Von Mutius is conducting research 832 00:50:52,749 --> 00:50:55,752 in a place where these conditions are rare... 833 00:50:57,754 --> 00:51:00,757 The Bavarian countryside. 834 00:51:00,757 --> 00:51:04,761 She wants to sort out exactly which environmental factors 835 00:51:04,761 --> 00:51:09,766 may be protecting children who grow up here. 836 00:51:09,766 --> 00:51:11,768 VON MUTIUS: The study we're doing 837 00:51:11,768 --> 00:51:13,770 is a comparison within little villages. 838 00:51:13,770 --> 00:51:17,274 So we compare children who live on the farm 839 00:51:17,274 --> 00:51:21,278 to children in the same village who do not live on the farm. 840 00:51:24,281 --> 00:51:27,284 NARRATOR: She has enlisted over 800 families 841 00:51:27,284 --> 00:51:30,287 with children between the ages of six and 12 842 00:51:30,287 --> 00:51:35,292 to participate in a detailed survey of health and lifestyle. 843 00:51:35,292 --> 00:51:38,295 Dann, wieviel Zeit... 844 00:51:38,295 --> 00:51:42,299 VON MUTIUS: In each questionnaire, we asked for allergic conditions 845 00:51:42,299 --> 00:51:43,800 and then most importantly 846 00:51:43,800 --> 00:51:46,303 we asked for the contact to farm animals 847 00:51:46,303 --> 00:51:49,306 and farming activities. 848 00:51:49,306 --> 00:51:54,811 (interview proceeding in German) 849 00:51:54,811 --> 00:51:56,813 NARRATOR: Her goal is to create 850 00:51:56,813 --> 00:51:59,316 a profile of environmental exposures 851 00:51:59,316 --> 00:52:00,817 for each child. 852 00:52:04,321 --> 00:52:08,825 Her team analyzes dust samples from carpets and bedding 853 00:52:08,825 --> 00:52:10,327 throughout the house 854 00:52:10,327 --> 00:52:14,331 for the presence of animal hair, dust mites and microorganisms. 855 00:52:16,833 --> 00:52:18,835 If the family keeps livestock 856 00:52:19,336 --> 00:52:22,839 samples from the stables are screened for microbes 857 00:52:22,839 --> 00:52:26,843 released in the shedding and droppings of animals. 858 00:52:28,345 --> 00:52:30,847 The study is in progress 859 00:52:30,847 --> 00:52:34,851 but preliminary results suggest one very strong correlation. 860 00:52:34,851 --> 00:52:37,854 VON MUTIUS: One of the factors 861 00:52:37,854 --> 00:52:41,358 that seems to be important is the contact to the livestock. 862 00:52:41,358 --> 00:52:44,861 These children, the more they are in the stables, um... 863 00:52:44,861 --> 00:52:47,364 and the earlier they are in the stables 864 00:52:47,364 --> 00:52:48,865 that this gives a protection 865 00:52:48,865 --> 00:52:50,867 against the development of allergies. 866 00:52:50,867 --> 00:52:55,872 NARRATOR: High levels of microorganisms in the stables 867 00:52:55,872 --> 00:53:00,377 may help prime a child's immune system for life. 868 00:53:02,379 --> 00:53:05,882 VON MUTIUS: Microbes have been around us always 869 00:53:05,882 --> 00:53:08,385 and probably we need to find a balance 870 00:53:08,885 --> 00:53:11,888 between eradicating the harmful effect of bacteria 871 00:53:11,888 --> 00:53:15,392 and maybe also taking the beneficial components of this. 872 00:53:15,392 --> 00:53:18,395 But this is really into the future. 873 00:53:18,395 --> 00:53:20,397 (cows mooing) 874 00:53:20,397 --> 00:53:24,901 NARRATOR: Our species evolved in a world awash with microbes 875 00:53:24,901 --> 00:53:27,904 crowded with other creatures. 876 00:53:27,904 --> 00:53:32,909 We've only begun to understand the value of this heritage. 877 00:53:34,911 --> 00:53:36,413 WILSON: Scientists and medical researchers 878 00:53:36,413 --> 00:53:40,417 who have focused on the subject are more and more in agreement 879 00:53:40,417 --> 00:53:42,419 that it's a big mistake for humanity 880 00:53:42,419 --> 00:53:46,423 to separate itself from the rest of the living world too much. 881 00:53:46,423 --> 00:53:49,926 The vast majority of species out there are our friends; 882 00:53:49,926 --> 00:53:52,429 they're not our enemies. 883 00:53:52,429 --> 00:53:54,931 And we not only benefit from them 884 00:53:54,931 --> 00:53:59,436 but as a whole, they are essential to our existence. 885 00:54:03,940 --> 00:54:06,943 We're the fortunate heirs 886 00:54:06,943 --> 00:54:10,947 of more than three billion years of evolution 887 00:54:10,947 --> 00:54:14,951 that created this stupendous diversity. 888 00:54:14,951 --> 00:54:21,958 We need to learn a lot more about the living world 889 00:54:21,958 --> 00:54:27,964 and the way that humanity itself is affecting evolution. 890 00:54:32,969 --> 00:54:37,974 NARRATOR: Like all living things, humans are a product of evolution. 891 00:54:37,974 --> 00:54:41,478 But we're the only species that knows it. 892 00:54:42,979 --> 00:54:45,982 We alone can see into the distant past 893 00:54:45,982 --> 00:54:48,985 and marvel at the history of life. 894 00:54:48,985 --> 00:54:51,988 We alone are beginning to understand 895 00:54:51,988 --> 00:54:55,492 that we can use evolution to shape the future 896 00:54:55,492 --> 00:54:56,493 for all of life. 897 00:54:58,495 --> 00:55:00,997 More than anything else 898 00:55:00,997 --> 00:55:05,001 this unique vision may be what makes us human. 899 00:55:50,080 --> 00:55:51,581 Continue the journey 900 00:55:51,581 --> 00:55:53,583 into where we're from and where we're going 901 00:55:53,583 --> 00:55:55,085 at the Evolution web site. 902 00:55:55,085 --> 00:55:58,088 Visit www.pbs.org. 903 00:55:58,088 --> 00:56:02,092 The seven-part Evolution boxed set and the companion book 904 00:56:02,092 --> 00:56:05,095 are available from WGBH Boston Video. 905 00:56:05,095 --> 00:56:07,097 To place an order, please call: