1 00:00:00,533 --> 00:00:01,901 (peaceful music) 2 00:00:01,901 --> 00:00:04,437 - Welcome to the beautiful island of Kauai. 3 00:00:04,437 --> 00:00:09,509 White sand beaches, tropical flowers, magnificent birds. 4 00:00:10,610 --> 00:00:12,045 You can't tell me this isn't paradise on Earth. 5 00:00:12,045 --> 00:00:13,580 Just look at it. 6 00:00:13,580 --> 00:00:14,414 (ominous music) 7 00:00:14,414 --> 00:00:15,715 But for over a century, 8 00:00:15,715 --> 00:00:18,151 this island has been a battleground, 9 00:00:18,151 --> 00:00:19,686 a frontline in the war 10 00:00:19,686 --> 00:00:22,655 against the deadliest animal in the world. 11 00:00:22,655 --> 00:00:23,590 (mosquitoes buzzing) 12 00:00:23,590 --> 00:00:25,125 Mosquitoes. 13 00:00:25,125 --> 00:00:26,393 (dramatic music) 14 00:00:26,393 --> 00:00:28,395 - [Narrator] DDT is the most powerful of weapons 15 00:00:28,395 --> 00:00:31,064 against the mosquitoes that carry malaria. 16 00:00:31,064 --> 00:00:34,768 - Mosquitoes are killing up to a million people a year. 17 00:00:34,768 --> 00:00:36,403 - It's a battle we've been losing, 18 00:00:36,403 --> 00:00:39,339 but the tide, it may be about to turn. 19 00:00:39,339 --> 00:00:42,075 (dramatic music) 20 00:00:44,978 --> 00:00:47,680 To understand exactly what's going on, 21 00:00:47,680 --> 00:00:50,984 we're joining two scientists who've made it their mission 22 00:00:50,984 --> 00:00:55,121 to stop the mosquito from devastating this island ecosystem: 23 00:00:55,121 --> 00:00:57,657 Cali Crampton and Cynthia King. 24 00:00:57,657 --> 00:00:59,059 - So down this way maybe. 25 00:00:59,059 --> 00:01:01,194 We're looking for pools of standing water 26 00:01:01,194 --> 00:01:03,329 that might have mosquito larvae in them. 27 00:01:03,329 --> 00:01:05,932 - [Baratunde] At an altitude of around 4,000 feet, 28 00:01:05,932 --> 00:01:10,070 the Alaka'i Plateau used to be too cold for mosquitoes. 29 00:01:10,070 --> 00:01:13,339 - This species particularly loves to have water 30 00:01:13,339 --> 00:01:16,042 with decomposing plant material in it, 31 00:01:16,042 --> 00:01:17,243 - [Baratunde] But with temperatures rising 32 00:01:17,243 --> 00:01:18,878 thanks to climate change, 33 00:01:18,878 --> 00:01:22,348 they're slowly making their way into higher altitudes. 34 00:01:22,348 --> 00:01:23,383 - What's that? - Oh, no, there's one. 35 00:01:23,383 --> 00:01:24,918 - Yeah, we got some. - Yes. 36 00:01:24,918 --> 00:01:27,487 - I don't usually have to describe what a mosquito is, 37 00:01:27,487 --> 00:01:29,756 because almost everybody knows what a mosquito is. 38 00:01:29,756 --> 00:01:33,860 It's arguably one of the most hated species in the world. 39 00:01:33,860 --> 00:01:35,462 - Now, to be fair to mosquitoes, 40 00:01:35,462 --> 00:01:37,464 there are thousands of species, 41 00:01:37,464 --> 00:01:40,300 and only a few bite us humans. 42 00:01:40,300 --> 00:01:43,136 But those few can cause a lot of misery, 43 00:01:43,136 --> 00:01:44,637 especially when they move to places 44 00:01:44,637 --> 00:01:46,306 where they don't normally belong. 45 00:01:46,306 --> 00:01:48,007 - It's really important to remember 46 00:01:48,007 --> 00:01:50,543 mosquitoes are not native to Hawaii. 47 00:01:50,543 --> 00:01:52,045 - [Baratunde] That's right, 48 00:01:52,045 --> 00:01:55,248 these little blood suckers are invasive species. 49 00:01:55,248 --> 00:01:57,450 And ever since they made themselves at home 50 00:01:57,450 --> 00:02:01,054 in the Hawaiian Islands, they've wreaked some serious havoc. 51 00:02:01,855 --> 00:02:04,791 So how did this tiny mosquito 52 00:02:04,791 --> 00:02:07,794 journey across vast oceans to get here? 53 00:02:07,794 --> 00:02:10,063 - All right, let's see if this will work. 54 00:02:10,063 --> 00:02:11,798 - [Baratunde] We asked Matthew Kurano, 55 00:02:11,798 --> 00:02:15,268 a public health official who knows his mosquitoes. 56 00:02:15,268 --> 00:02:17,904 - [Matthew] Hawaii is very much a paradise, 57 00:02:17,904 --> 00:02:21,141 and pre Western contact, there was no mosquitoes, 58 00:02:21,141 --> 00:02:22,642 - [Baratunde] But in the 1800s, 59 00:02:22,642 --> 00:02:26,412 the whaling industry brought tons of ships to Hawaii. 60 00:02:26,412 --> 00:02:29,149 It just took a few mosquitoes to hitch a ride, 61 00:02:29,149 --> 00:02:30,650 and here we are. 62 00:02:30,650 --> 00:02:32,886 - The mosquitoes established pretty rapidly in Hawaii, 63 00:02:32,886 --> 00:02:35,955 particularly because we're a very tropical, beautiful, 64 00:02:35,955 --> 00:02:38,258 sadly mosquito-friendly area. 65 00:02:39,392 --> 00:02:41,294 Once the populations of mosquitoes established, 66 00:02:41,294 --> 00:02:44,330 then all it took was people to bring the disease. 67 00:02:44,330 --> 00:02:46,599 - [Baratunde] As if those mosquitoes weren't enough, 68 00:02:46,599 --> 00:02:48,601 people also brought pathogens. 69 00:02:48,601 --> 00:02:51,704 Mosquitoes bit them and then bit other people, 70 00:02:51,704 --> 00:02:55,842 a perfect recipe for spreading disease across the islands. 71 00:02:55,842 --> 00:02:57,577 - Mosquitoes are the most deadly animal 72 00:02:57,577 --> 00:02:59,078 in the world to humans. 73 00:02:59,078 --> 00:03:01,814 One of the most significant risks they pose 74 00:03:01,814 --> 00:03:04,817 is as vectors of human diseases. 75 00:03:04,817 --> 00:03:07,587 - Hawaii has had historic outbreaks. 76 00:03:07,587 --> 00:03:09,289 One of the more notable ones in history 77 00:03:09,289 --> 00:03:10,990 occurred right around 1900, 78 00:03:10,990 --> 00:03:15,295 and we did have a larger outbreak of dengue. 79 00:03:15,295 --> 00:03:17,363 - Chemical controls are the most common ways 80 00:03:17,363 --> 00:03:20,166 that humans typically deal with mosquitoes. 81 00:03:20,166 --> 00:03:21,634 - [Narrator] The answer to the quest 82 00:03:21,634 --> 00:03:26,239 for a poison to eradicate the insects was found in DDT. 83 00:03:27,340 --> 00:03:28,274 - [Baratunde] It's hard to imagine now, 84 00:03:28,274 --> 00:03:29,842 but there was a time when DDT 85 00:03:29,842 --> 00:03:33,613 was considered a miracle pesticide, and it was everywhere. 86 00:03:33,613 --> 00:03:35,782 We considered it a vital weapon 87 00:03:35,782 --> 00:03:37,817 in the war against mosquitoes. 88 00:03:37,817 --> 00:03:40,153 - [Narrator] If the worker stands to windward, 89 00:03:40,153 --> 00:03:44,357 it is not necessary to wear a mask when dispensing DDT dust. 90 00:03:44,357 --> 00:03:45,592 - Now, I don't know about you, 91 00:03:45,592 --> 00:03:47,493 but when there's poison in the air, 92 00:03:47,493 --> 00:03:50,763 simply standing upwind isn't gonna cut it for me. 93 00:03:50,763 --> 00:03:53,666 - Several agricultural chemicals, such as DDT, 94 00:03:53,666 --> 00:03:55,301 have been banned from general use 95 00:03:55,301 --> 00:03:58,137 because of potential hazards to man and animals. 96 00:03:58,137 --> 00:04:00,673 - [Baratunde] At high doses, the pesticide was linked 97 00:04:00,673 --> 00:04:04,344 to vomiting, tremors, even seizures. 98 00:04:04,344 --> 00:04:06,012 - [Matthew] My parents always talk about 99 00:04:06,012 --> 00:04:10,483 that there'd be DDT trucks leaving a cloud, a fog behind it. 100 00:04:10,483 --> 00:04:14,254 And we don't wanna see children playing in pesticide clouds. 101 00:04:14,254 --> 00:04:15,989 I think we can all agree that that 102 00:04:15,989 --> 00:04:18,224 is not in the interest of public health. 103 00:04:18,224 --> 00:04:20,994 - That's all well and good, but without DDT, 104 00:04:20,994 --> 00:04:24,464 we've lost our most effective weapon against mosquitoes. 105 00:04:24,464 --> 00:04:26,332 We need something new. 106 00:04:26,332 --> 00:04:28,134 (record scratching) 107 00:04:28,134 --> 00:04:32,405 Flash forward to a lab in Lexington, Kentucky. 108 00:04:32,405 --> 00:04:35,275 This is medical entomologist Steven Dobson, 109 00:04:35,275 --> 00:04:38,044 who's working on a new approach to mosquito control. 110 00:04:38,044 --> 00:04:40,046 - I like to tell people that we manufacture 111 00:04:40,046 --> 00:04:43,149 and sell mosquitoes and just see what their reaction is. 112 00:04:43,149 --> 00:04:47,320 Usually they'll nod, and then you'll see them double take. 113 00:04:47,320 --> 00:04:49,289 - At first, it doesn't seem like much 114 00:04:49,289 --> 00:04:51,891 when you see Stephen dropping by people's backyards, 115 00:04:51,891 --> 00:04:54,761 tapping on small cardboard tubes, 116 00:04:54,761 --> 00:04:58,464 until you realize that what Steven is really doing 117 00:04:58,464 --> 00:05:01,200 is releasing thousands of mosquitoes. 118 00:05:01,200 --> 00:05:02,201 (mosquitoes buzzing) 119 00:05:02,201 --> 00:05:03,603 Now, I know what you're thinking. 120 00:05:03,603 --> 00:05:04,871 Why would you do that, 121 00:05:04,871 --> 00:05:07,407 release more of these things into the wild? 122 00:05:07,407 --> 00:05:10,543 But these are no ordinary mosquitoes. 123 00:05:10,543 --> 00:05:13,012 These insects have been deliberately infected 124 00:05:13,012 --> 00:05:16,582 with a naturally occurring bacteria called wolbachia. 125 00:05:19,419 --> 00:05:20,687 (zipper zips) 126 00:05:20,687 --> 00:05:24,123 - We are using wolbachia as a way to cause 127 00:05:24,123 --> 00:05:26,959 a form of sterility in mosquitoes. 128 00:05:26,959 --> 00:05:29,929 - [Baratunde] Okay, this all sounds a little strange, 129 00:05:29,929 --> 00:05:31,331 but bear with me. 130 00:05:31,331 --> 00:05:33,166 Stephen is breeding mosquitoes 131 00:05:33,166 --> 00:05:35,835 that carry the wolbachia bacteria. 132 00:05:35,835 --> 00:05:39,939 Then he releases a bunch of them, but only the males. 133 00:05:39,939 --> 00:05:41,474 - We release the males, 134 00:05:41,474 --> 00:05:43,676 who are now mating with the females, 135 00:05:43,676 --> 00:05:45,411 and effectively sterilizing them. 136 00:05:45,411 --> 00:05:46,679 By continuing to release, 137 00:05:46,679 --> 00:05:49,482 the population just goes down with every release 138 00:05:49,482 --> 00:05:52,285 until we don't have that species anymore. 139 00:05:52,285 --> 00:05:53,786 - [Baratunde] Got that? 140 00:05:53,786 --> 00:05:56,956 The lab grown-males with the artificially inserted bacteria 141 00:05:56,956 --> 00:06:00,526 mate with the wild females that don't have the bacteria, 142 00:06:00,526 --> 00:06:03,663 basically interfering with their reproductive process, 143 00:06:03,663 --> 00:06:05,765 stopping their eggs from hatching, 144 00:06:05,765 --> 00:06:08,067 and the results speak for themselves. 145 00:06:08,868 --> 00:06:10,236 - In the laboratory, 146 00:06:10,236 --> 00:06:12,739 we can completely eliminate caged populations. 147 00:06:12,739 --> 00:06:14,107 In the real world, 148 00:06:14,107 --> 00:06:16,008 we're still seeing reductions in the population 149 00:06:16,008 --> 00:06:18,077 that exceed 95%. 150 00:06:18,077 --> 00:06:21,013 - [Baratunde] Plus, unlike the old DDT days, 151 00:06:21,013 --> 00:06:23,383 which wiped out tons of wildlife, 152 00:06:23,383 --> 00:06:26,386 this method is highly targeted. 153 00:06:26,386 --> 00:06:29,622 - These males we release, they only mate with one species. 154 00:06:29,622 --> 00:06:31,090 You'll never find a male mosquito 155 00:06:31,090 --> 00:06:33,292 trying to mate with a butterfly or a bee. 156 00:06:33,292 --> 00:06:36,229 - Of the 3,000-plus known mosquito species, 157 00:06:36,229 --> 00:06:38,865 only 6% bite human, 158 00:06:38,865 --> 00:06:42,835 and only 2% are responsible for mosquito-borne illnesses. 159 00:06:42,835 --> 00:06:46,172 The goal is to target only those mosquitoes. 160 00:06:46,172 --> 00:06:48,808 So, in theory, the wolbachia technique 161 00:06:48,808 --> 00:06:51,911 leaves the vast majority of mosquitoes alone. 162 00:06:52,678 --> 00:06:54,180 This is a good thing, 163 00:06:54,180 --> 00:06:57,016 since mosquitoes can be great sources of food for animals 164 00:06:57,016 --> 00:06:59,018 and incredible pollinators. 165 00:06:59,018 --> 00:07:01,721 Of course, this system is in its infancy, 166 00:07:01,721 --> 00:07:02,955 and scientists caution 167 00:07:02,955 --> 00:07:04,991 that it needs to be rolled out with care. 168 00:07:04,991 --> 00:07:09,195 But if it works, the potential benefits are massive. 169 00:07:09,195 --> 00:07:13,833 So, can wolbachia make a difference in a place like Kauai? 170 00:07:13,833 --> 00:07:15,468 Let's hope so, 171 00:07:15,468 --> 00:07:18,538 because mosquitoes, they're not just deadly to humans; 172 00:07:18,538 --> 00:07:22,141 they're also decimating some of Earth's rarest birds. 173 00:07:24,544 --> 00:07:27,013 (soft music) 174 00:07:28,114 --> 00:07:29,982 - [Cali] There are birds here on Kauai 175 00:07:29,982 --> 00:07:32,151 that are found nowhere else in the Hawaii world. 176 00:07:32,151 --> 00:07:34,253 There are six different species. 177 00:07:34,253 --> 00:07:36,088 - [Baratunde] Cali is the project leader 178 00:07:36,088 --> 00:07:39,392 of the Kauai Forest Bird Recovery Project. 179 00:07:39,392 --> 00:07:42,128 - These six species are very, very susceptible 180 00:07:42,128 --> 00:07:44,163 to the mosquito-borne avian malaria. 181 00:07:44,163 --> 00:07:45,331 They evolved without mosquitoes 182 00:07:45,331 --> 00:07:46,732 and they evolved without avian malaria, 183 00:07:46,732 --> 00:07:50,536 so they have no resistance to avian malaria, 184 00:07:50,536 --> 00:07:52,672 - [Baratunde] And it's not just Kauai. 185 00:07:52,672 --> 00:07:54,574 Native birds on other islands 186 00:07:54,574 --> 00:07:57,944 are also endangered by this mosquito invasion. 187 00:07:57,944 --> 00:08:00,780 - One of the species, for example, the 'i'iwi, 188 00:08:00,780 --> 00:08:02,281 in cage trials, we have documented 189 00:08:02,281 --> 00:08:04,817 that nine of 10 of them will die 190 00:08:04,817 --> 00:08:07,220 after being bitten just once 191 00:08:07,220 --> 00:08:09,522 by a mosquito carrying avian malaria. 192 00:08:09,522 --> 00:08:11,190 The tremendous amount of harm 193 00:08:11,190 --> 00:08:13,359 mosquitoes are doing to those ecosystems 194 00:08:13,359 --> 00:08:16,996 by killing off all these birds is staggering. 195 00:08:16,996 --> 00:08:18,531 - [Baratunde] That's why Hawaii is planning 196 00:08:18,531 --> 00:08:20,867 to release wolbachia-infected mosquitoes 197 00:08:20,867 --> 00:08:22,401 on some of their islands, 198 00:08:22,401 --> 00:08:24,670 targeting the specific species of mosquito 199 00:08:24,670 --> 00:08:26,839 that transmit malaria in birds 200 00:08:26,839 --> 00:08:28,808 and West Nile virus in people. 201 00:08:28,808 --> 00:08:31,077 (dramatic music) 202 00:08:31,077 --> 00:08:32,912 - [Cali] Here on Kauai, 203 00:08:32,912 --> 00:08:36,182 the plan is to do some of the preliminary research 204 00:08:36,182 --> 00:08:37,617 to understand the movement patterns 205 00:08:37,617 --> 00:08:40,286 and the survival patterns of males this fall. 206 00:08:40,286 --> 00:08:43,723 - [Baratunde] Large-scale releases are planned for 2024. 207 00:08:43,723 --> 00:08:47,627 Sadly, for some of the birds this will be too late. 208 00:08:47,627 --> 00:08:51,297 - In 2012, we estimated 209 00:08:51,297 --> 00:08:53,666 that there were 500 'akikiki left here, 210 00:08:53,666 --> 00:08:57,303 which is already a frighteningly low number. 211 00:08:57,303 --> 00:08:58,571 By the end of this year, 212 00:08:58,571 --> 00:09:00,540 we expect that they will be extinct in the wild. 213 00:09:01,474 --> 00:09:02,808 - As a mainlander, 214 00:09:02,808 --> 00:09:06,779 this is a painful reality just to witness, 215 00:09:06,779 --> 00:09:08,314 but for native communities, 216 00:09:08,314 --> 00:09:11,317 the loss is almost inconceivable. 217 00:09:12,285 --> 00:09:14,520 (delicate music) 218 00:09:14,520 --> 00:09:17,590 - So we're in a traditional house. 219 00:09:17,590 --> 00:09:18,824 We call them hale. 220 00:09:19,926 --> 00:09:21,294 - [Baratunde] Lei Wann is the Director 221 00:09:21,294 --> 00:09:24,363 of Limahuli Garden and Preserve in Kauai, 222 00:09:24,363 --> 00:09:26,032 in a biodiverse valley that's home 223 00:09:26,032 --> 00:09:29,435 to dozens of endangered plants and birds. 224 00:09:29,435 --> 00:09:31,804 - My ancestors come from this valley, 225 00:09:31,804 --> 00:09:34,840 and many of them come from this land. 226 00:09:34,840 --> 00:09:36,175 Because our culture, 227 00:09:36,175 --> 00:09:39,946 there are really lines between us and birds. 228 00:09:39,946 --> 00:09:43,249 We see them as part of our family. 229 00:09:43,249 --> 00:09:45,851 To think that our children 230 00:09:45,851 --> 00:09:50,323 won't have those connections with family members, 231 00:09:50,323 --> 00:09:52,024 it's devastating 232 00:09:52,024 --> 00:09:53,626 - [Baratunde] To prevent their extinction. 233 00:09:53,626 --> 00:09:56,629 The 'akikiki are being moved to the island of Maui 234 00:09:56,629 --> 00:09:59,732 until the Kauai mosquito problem is fixed. 235 00:09:59,732 --> 00:10:01,334 - It was super emotional, 236 00:10:01,334 --> 00:10:03,736 because now we have to ask Maui 237 00:10:03,736 --> 00:10:06,372 to carry on that responsibility. 238 00:10:06,372 --> 00:10:09,775 We're talking a lot about 'akikiki and 'akeke, 239 00:10:09,775 --> 00:10:12,545 but I hear 'i'iwi are next, 240 00:10:12,545 --> 00:10:14,947 and the next species is near 241 00:10:14,947 --> 00:10:18,250 very threatening levels of extinction. 242 00:10:18,250 --> 00:10:21,120 The time to respond, to act is now. 243 00:10:21,120 --> 00:10:23,723 It was yesterday. It was a month ago. 244 00:10:24,690 --> 00:10:26,826 - Mosquitoes are so small, 245 00:10:26,826 --> 00:10:29,729 we don't notice them until they leave a bite behind, 246 00:10:29,729 --> 00:10:33,766 yet the impact they have on the world is hard to ignore. 247 00:10:33,766 --> 00:10:35,534 Without human activity, 248 00:10:35,534 --> 00:10:37,870 like globalization and climate change, 249 00:10:37,870 --> 00:10:40,740 this little pest wouldn't have such a lasting effect 250 00:10:40,740 --> 00:10:42,475 on our lives and environment. 251 00:10:42,475 --> 00:10:45,411 The reality is we are responsible 252 00:10:45,411 --> 00:10:48,447 for our complicated relationship with mosquitoes. 253 00:10:48,447 --> 00:10:51,117 It's up to us to call a truce. 254 00:10:51,117 --> 00:10:55,588 - I believe that wolbachia is the best chance that we have 255 00:10:55,588 --> 00:10:58,357 to save the remaining species on Kauai. 256 00:10:58,357 --> 00:11:00,693 But beyond that, there's great hopes 257 00:11:00,693 --> 00:11:05,197 that this tool will be useful to benefit human health. 258 00:11:05,197 --> 00:11:08,034 - Because sometimes the best way to win 259 00:11:08,034 --> 00:11:10,603 isn't to wage an all-out war. 260 00:11:10,603 --> 00:11:12,071 The best way to win 261 00:11:12,071 --> 00:11:15,608 is to recruit some lab-grown mosquitoes to our side. 262 00:11:17,043 --> 00:11:18,844 Thanks so much for watching. 263 00:11:18,844 --> 00:11:21,547 For more great tales from the great outdoors, 264 00:11:21,547 --> 00:11:24,083 check out season two of "America Outdoors" 265 00:11:24,083 --> 00:11:25,918 with Baratunde Thurston. 266 00:11:25,918 --> 00:11:29,622 You can find us in the PBS app or your local PBS station. 267 00:11:29,622 --> 00:11:31,691 Check the link in the description below 268 00:11:31,691 --> 00:11:34,126 to watch a full episode and find out more.