Full Transcript for Zika

Ultimately, they realized, hey, 78 00:03:37.750 --> 00:03:40.610 it's something new, and they named it Zika virus after 79 00:03:40.629 --> 00:03:41.669 the forest where the monkey had. 80 00:03:43.210 --> 00:03:46.060 Do we know who was the first human patient to 81 00:03:46.099 --> 00:03:47.020 get sick with Zika? 82 00:03:47.080 --> 00:03:48.259 Was there a patient zero? 83 00:03:49.159 --> 00:03:53.780 We know who the first human in whom the Zika 84 00:03:53.800 --> 00:03:57.520 virus was discovered. She was a 10-year-old girl in Nigeria. 85 00:03:58.319 --> 00:04:00.879 They did some interesting research then where they actually drew 86 00:04:00.939 --> 00:04:03.479 blood from an entire village near the lab in Nigeria 87 00:04:03.870 --> 00:04:05.759 to see if they had what we now know are 88 00:04:05.819 --> 00:04:08.710 antibodies to Zika, and like 60% of the village did. 89 00:04:09.539 --> 00:04:12.080 OK, so the fact that 60% of the village had 90 00:04:12.240 --> 00:04:16.759 antibodies to Zika suggests that those people were actually infected 91 00:04:16.819 --> 00:04:19.300 with the virus at one point in their lives. 92 00:04:20.040 --> 00:04:22.089 And Donald says that even though Zika. 93 00:04:21.850 --> 00:04:25.850 Wasn't discussed in the scientific community until around the 1950s, 94 00:04:26.490 --> 00:04:30.110 Zika has probably been around parts of Africa for thousands 95 00:04:30.189 --> 00:04:34.980 of years, infecting monkeys and people. But Donald says that 96 00:04:35.459 --> 00:04:39.889 Zika really wasn't considered to be so scary. That Nigerian girl, 97 00:04:39.990 --> 00:04:42.420 she had a headache and a fever, but that was 98 00:04:42.480 --> 00:04:42.939 about it. 99 00:04:43.639 --> 00:04:45.819 It was a relatively mild disease. There was a scientist 100 00:04:45.839 --> 00:04:48.420 who deliberately gave himself Zika in order to describe the effects. 101 00:04:49.500 --> 00:04:52.540 Europeans, they just got to make it about them, don't they? 102 00:04:53.319 --> 00:04:53.579 Yeah. 103 00:04:53.600 --> 00:04:56.329 He injected himself and then described the effects on himself. 104 00:04:56.990 --> 00:04:58.769 But it was a relatively mild disease. 105 00:04:58.790 --> 00:05:02.509 Okay, so after this buzz of research, no pun intended, 106 00:05:03.009 --> 00:05:07.350 some pun intended, For the next six decades, Zika was 107 00:05:07.490 --> 00:05:10.730 only mentioned about a dozen times in the scientific literature. 108 00:05:10.870 --> 00:05:13.290 And when it was, it was describing just a few 109 00:05:13.370 --> 00:05:18.399 people who were infected in Senegal, Pakistan, Indonesia, Cambodia. But 110 00:05:18.439 --> 00:05:23.300 no one got that sick, no deaths, no hospitalisations, just fever, 111 00:05:23.420 --> 00:05:27.879 rashes and chills. And again, not that many people got 112 00:05:27.959 --> 00:05:29.189 infected at once. 113 00:05:29.870 --> 00:05:31.269 But then in 2007, Zika turns up in a big way. 114 00:05:34.939 --> 00:05:36.529 on the island of Yap. 115 00:05:37.329 --> 00:05:40.209 Yap is a tiny island in the Pacific Ocean, just 116 00:05:40.329 --> 00:05:42.810 north of Papua New Guinea and east of the Philippines. 117 00:05:43.410 --> 00:05:46.509 So a doctor on Yap contacted the Centers for Disease 118 00:05:46.550 --> 00:05:49.750 Control and said, hey, we're having some sort of outbreak. 119 00:05:49.769 --> 00:05:52.410 Can you help me figure out what's going on? Here's 120 00:05:52.430 --> 00:05:53.029 Donald again. 121 00:05:53.930 --> 00:05:56.189 So a team went from the CDC there and they, 122 00:05:56.470 --> 00:05:58.829 you know, started seeing patients and pulled blood and said, 123 00:05:59.069 --> 00:06:02.339 this is Zika virus. It hit the island. It, it, um, 124 00:06:03.160 --> 00:06:05.759 hit 73% of the island population within six months and 125 00:06:05.779 --> 00:06:08.600 then disappeared. That was end of epidemic. And there hasn't 126 00:06:08.620 --> 00:06:09.819 been a case on Yap Island since. 127 00:06:10.259 --> 00:06:14.920 In Yap, did we start to see serious complications, microcephaly. 128 00:06:14.959 --> 00:06:15.480 Things like that? 129 00:06:15.600 --> 00:06:15.759 No. 130 00:06:16.240 --> 00:06:19.040 In Yap, it was considered a mild virus. 131 00:06:19.980 --> 00:06:22.339 So how did we get from hundreds of people on 132 00:06:22.379 --> 00:06:26.139 an island in the Pacific with just flu-like symptoms to 133 00:06:26.160 --> 00:06:30.579 the situation that we have now? Well, the first hint 134 00:06:30.680 --> 00:06:33.730 that Zika could become serious was when the infection hit 135 00:06:33.829 --> 00:06:39.810 French Polynesia. This was in 2013. It was estimated that 30,000 people, 136 00:06:39.910 --> 00:06:42.930 roughly 10% of the population, went to the doctor because 137 00:06:42.970 --> 00:06:47.050 of Zika infections. And it was during this outbreak that 138 00:06:47.129 --> 00:06:52.660 doctors started seeing an unusual increase in another condition, Guillain-Barre syndrome. 139 00:06:53.800 --> 00:06:56.519 This is a temporary and very rare disease which can 140 00:06:56.579 --> 00:07:00.180 lead to paralysis and it can come on very suddenly. Usually, 141 00:07:00.339 --> 00:07:02.740 maybe a couple of people on these islands might be 142 00:07:02.800 --> 00:07:07.300 affected by this in a year. But during the outbreak, 143 00:07:07.300 --> 00:07:11.800 41 people with Zika infections got it. Then we started 144 00:07:11.860 --> 00:07:15.920 hearing about Zika hitting Brazil. By the end of 2015, 145 00:07:15.920 --> 00:07:20.259 the Brazil Ministry of Health estimated that between 500,000 to 1.5 146 00:07:20.259 --> 00:07:20.699 million people. 147 00:07:24.300 --> 00:07:31.019 Were infected with Zika. And then things got worse. Their 148 00:07:31.060 --> 00:07:33.889 small faces number in the thousands in Brazil. 149 00:07:34.230 --> 00:07:38.610 Their mothers worried about

developmental delay because of microcephaly. 150 00:07:40.850 --> 00:07:43.689 And how did the Brazil government, because they were the 151 00:07:43.730 --> 00:07:45.089 first to realize this connection. 152 00:07:45.129 --> 00:07:47.300 It was actually individual doctors in Brazil who noticed it. 153 00:07:47.509 --> 00:07:50.610 Doctors who worked in the pediatric intensive care units suddenly 154 00:07:50.649 --> 00:07:53.850 began saying to each other, hey, I've got five babies 155 00:07:53.889 --> 00:07:56.040 with microcephaly in my unit. And actually, one of them 156 00:07:56.060 --> 00:07:59.259 was a mother-daughter team. They were both pediatric intensive care 157 00:07:59.279 --> 00:08:02.139 specialists at different hospitals. And they began talking to each 158 00:08:02.180 --> 00:08:05.019 other and saying, I've got seven in my hospital. I 159 00:08:05.060 --> 00:08:08.259 normally don't see a baby with microcephaly more than once 160 00:08:08.319 --> 00:08:10.819 a year or once every couple of years. Something's going on. 161 00:08:10.980 --> 00:08:13.639 And so the doctors began consulting with each other. And 162 00:08:13.689 --> 00:08:15.850 they realized that something terribly alarming was going on. 163 00:08:16.600 --> 00:08:19.360 The doctors in Brazil started to suspect that Zika was 164 00:08:19.439 --> 00:08:22.980 causing the microcephaly pretty much because of the timing. A 165 00:08:23.060 --> 00:08:25.939 bunch of new cases of Zika, and then several months later, 166 00:08:25.959 --> 00:08:29.939 a bunch of new cases of microcephaly. So, to explain 167 00:08:30.040 --> 00:08:32.779 how a mother being bit by a mosquito can suddenly 168 00:08:32.840 --> 00:08:37.710 produce babies with abnormally small heads, we talked to Desiree Lebeau, 169 00:08:37.850 --> 00:08:42.190 an associate professor of paediatric infectious diseases at Stanford University. 170 00:08:42.990 --> 00:08:48.409 Desiree specializes in diseases spread by mosquitoes. And she loves 171 00:08:48.529 --> 00:08:51.519 her job and loves what she studies. 172 00:08:52.139 --> 00:08:57.100 I'm an arbovirologist. So all arbovirologists love their arboviruses. 173 00:08:57.220 --> 00:08:59.340 What exactly is an arbovirus? 174 00:08:59.940 --> 00:09:05.070 Yeah, so an arbovirus stands for arthropod-borne virus. So this 175 00:09:05.149 --> 00:09:08.870 is a virus that uses a blood-sucking arthropod to complete 176 00:09:08.909 --> 00:09:11.789 its life cycle. I study ones that are spread mainly 177 00:09:11.850 --> 00:09:14.389 by mosquitoes, but you can have other arboviruses that are 178 00:09:14.409 --> 00:09:18.360 spread by other arthropod vectors, like ticks and other insects. 179 00:09:19.220 --> 00:09:22.039 Now, tell me how exactly, I mean, I know there's 180 00:09:22.059 --> 00:09:23.340 lots of unknowns here, but what. 181 00:09:23.240 --> 00:09:23.639 Do we know? 182 00:09:23.720 --> 00:09:27.809 How exactly does the Zika virus cause microcephaly?

183 00:09:28.710 --> 00:09:31.360 So right now, the thinking is that when a woman 184 00:09:31.649 --> 00:09:36.039 is infected, she has the virus in her bloodstream. That 185 00:09:36.159 --> 00:09:39.919 virus can then cross over the placental barrier into the placenta. 186 00:09:40.220 --> 00:09:42.879 And then it travels into the developing fetus. And it 187 00:09:42.960 --> 00:09:47.360 has sort of what we call neurotropism. So it actually 188 00:09:47.399 --> 00:09:49.440 is sort of drawn to the neural structures of the 189 00:09:49.500 --> 00:09:54.539 developing fetal brain. And so it infects those structures. inhibiting 190 00:09:54.580 --> 00:09:59.649 their normal growth processes. Microcephaly is one aspect of the 191 00:09:59.690 --> 00:10:04.659 congenital Zika virus syndrome. But as time goes on, you know, 192 00:10:04.679 --> 00:10:07.169 we're starting to understand more and more of the entire 193 00:10:07.269 --> 00:10:08.370 bell-shaped curve. 194 00:10:09.029 --> 00:10:12.009 So when you say a bell-shaped curve, you mean there 195 00:10:12.049 --> 00:10:15.230 might be more subtle things going on rather than just microcephaly? 196 00:10:15.870 --> 00:10:18.370 Absolutely. So microcephaly is an easy thing to see, right? 197 00:10:18.389 --> 00:10:20.509 When the child is born and their head is very small, 198 00:10:20.549 --> 00:10:23.019 it's an easy thing for someone to pick up, but 199 00:10:23.039 --> 00:10:27.259 they're probably going to be more and more subtle. effects 200 00:10:27.679 --> 00:10:30.929 of Zika virus infection on babies. Probably not all those 201 00:10:30.970 --> 00:10:33.970 babies will have microcephaly. Maybe some will have hearing deficits. 202 00:10:34.009 --> 00:10:36.470 Some may have vision deficits. Some may have other learning 203 00:10:36.529 --> 00:10:40.610 problems or other deformities within the brain. And I wasn't 204 00:10:40.649 --> 00:10:45.350 around when the rubella virus was found to be a 205 00:10:45.370 --> 00:10:49.590 congenitally exposed virus and cause problems with babies whose moms 206 00:10:49.629 --> 00:10:52.049 happened to get rubella during pregnancy. But I was told 207 00:10:52.090 --> 00:10:54.889 in the 50s and 60s when that was going on, Yes, initially, 208 00:10:54.909 --> 00:10:57.490 you know, they saw microcephaly, but then as time went on, 209 00:10:57.529 --> 00:11:00.480 they started to realize, oh, there were other eye complications 210 00:11:00.500 --> 00:11:02.669 that are due to rubella. There are heart complications that 211 00:11:02.720 --> 00:11:04.480 are due to rubella and so forth. And so that 212 00:11:04.519 --> 00:11:06.779 came out later. And I think that's just what we'll 213 00:11:06.820 --> 00:11:09.500 find with Zika. I think microcephaly is sort of like 214 00:11:09.580 --> 00:11:11.399 the tip of the iceberg, and we'll probably find a 215 00:11:11.440 --> 00:11:15.159 lot of other longstanding complications from in utero exposure. 216 00:11:16.120 --> 00:11:17.820 And what about in adults? 217 00:11:17.899 --> 00:11:21.820 Are we seeing that Zika likes to attack the brains 218 00:11:21.860 --> 00:11:22.639 of adults as well? 219 00:11:23.879 --> 00:11:27.669 Many, many arboviruses are able to cause infection of the 220 00:11:27.710 --> 00:11:30.789 brain because a lot of them are so neurotropic. And 221 00:11:30.870 --> 00:11:35.549 so it's possible that Zika virus will join its friends, 222 00:11:35.629 --> 00:11:39.820 the other arboviruses, and be able to cause these sort 223 00:11:39.840 --> 00:11:43.340 of spectra of disease in adults. But what I can 224 00:11:43.399 --> 00:11:45.919 say is that it does look like Zika virus has 225 00:11:45.940 --> 00:11:49.299 been associated with increased risk of Guillain-Barre syndrome. 226 00:11:49.679 --> 00:11:53.940 Remember that rare form of paralysis, Guillain-Barre syndrome? Well, during 227 00:11:53.980 --> 00:11:57.179 the Zika outbreak in Brazil, they did see more of it. 228 00:11:57.340 --> 00:12:00.480 Still very rare, but it did pop up more and more. 229 00:12:01.039 --> 00:12:04.700 It's a reversible phenomenon. Usually you aren't left with long-standing 230 00:12:04.740 --> 00:12:08.000 health complications after you suffer from Guillain-Barre, but you do 231 00:12:08.039 --> 00:12:10.779 need to be supported during that time when you're most ill. 232 00:12:11.340 --> 00:12:15.360 Like, from the virus's perspective, why is it so attracted 233 00:12:15.759 --> 00:12:17.340 to the brain and the nerve system? 234 00:12:17.379 --> 00:12:18.799 What's it doing once it's there? 235 00:12:19.970 --> 00:12:22.429 I'm not sure if we know that exactly. At this time, 236 00:12:22.470 --> 00:12:24.570 there are lots of people working on, you know, how 237 00:12:24.590 --> 00:12:26.600 does it cross the placental barrier? 238 00:12:27.019 --> 00:12:28.179 Desiree told us that one. 239 00:12:28.100 --> 00:12:31.379 Of the big ideas about how Zika is causing microcephaly 240 00:12:31.720 --> 00:12:35.840 is this. Zika gets inside brain cells by unlocking what 241 00:12:35.879 --> 00:12:39.720 are called receptors on the cells of fetuses developing brains. 242 00:12:40.399 --> 00:12:42.820 You can think of receptors as little locks that protect 243 00:12:42.860 --> 00:12:45.259 the cells, and to get inside these cells, you need 244 00:12:45.279 --> 00:12:49.909 a key. Zika seems to have that key. And that 245 00:12:49.950 --> 00:12:55.110 means that Zika can get inside fetuses' brains and cause havoc. 246 00:12:56.009 --> 00:12:58.289 Yes, exactly. So it could be that, yeah, the Zika 247 00:12:58.330 --> 00:13:01.299 virus has the key and then all of these early 248 00:13:01.399 --> 00:13:04.759 brain cells have the lock and does the placenta. So 249 00:13:04.820 --> 00:13:07.600 the virus is actually able to use that key lock 250 00:13:07.639 --> 00:13:10.460 to get across the placental barrier and then set up 251 00:13:10.559 -->

00:13:11.990 shop in the developing brain. 252 00:13:12.350 --> 00:13:15.529 Is the Zika virus replicating in the brain cells as well? 253 00:13:16.309 --> 00:13:16.509 Yes. 254 00:13:17.559 --> 00:13:20.250 Can you take us through that process? Like, does it 255 00:13:20.500 --> 00:13:25.009 use human cells to make itself replicate? 256 00:13:25.029 --> 00:13:27.509 Yeah, that's usually what viruses do. So they sort of 257 00:13:27.590 --> 00:13:31.429 set up shop and make yourselves a viral factory. And 258 00:13:31.470 --> 00:13:34.259 then that, you know, that one cell will produce many, many, 259 00:13:34.360 --> 00:13:37.559 many viruses that will then go on to infect other 260 00:13:37.600 --> 00:13:41.659 cells and so forth. And in the case of Zika 261 00:13:41.700 --> 00:13:44.559 virus infection, unlike the herpes virus infections, it doesn't really 262 00:13:44.620 --> 00:13:48.169 stay behind and integrate in your host cell. genetic material. 263 00:13:48.210 --> 00:13:51.830 It doesn't integrate into your DNA. It just comes in, 264 00:13:51.870 --> 00:13:53.710 it sets up shop and it, you know, kills the 265 00:13:53.769 --> 00:13:55.730 cell that it set the shop up in. 266 00:13:56.409 --> 00:13:59.789 Tell me, there's lots of concern out there. How worried 267 00:14:00.240 --> 00:14:03.259 should people be? So what are the chances that your 268 00:14:03.279 --> 00:14:07.179 baby will get microcephaly if you're infected with Zika and 269 00:14:07.220 --> 00:14:07.799 you're pregnant? 270 00:14:08.379 --> 00:14:10.620 We don't know the numbers. You know, I can't say 271 00:14:11.840 --> 00:14:14.419 what the risk is. I would say for pregnant women 272 00:14:14.490 --> 00:14:17.899 here in the U.S., you want to avoid being in 273 00:14:17.919 --> 00:14:22.100 an area that's having Zika virus transmission right now, because 274 00:14:22.139 --> 00:14:25.259 we don't know those answers yet. And there isn't a 275 00:14:25.259 --> 00:14:28.409 100% way that you can protect yourself from mosquitoes. We 276 00:14:28.429 --> 00:14:31.929 can try and do our very best with protecting ourselves 277 00:14:32.009 --> 00:14:35.269 using personal protective equipment, wearing pants and long sleeves, wearing 278 00:14:35.730 --> 00:14:41.029 DEET or picaridin, some effective mosquito repellent, But, you know, 279 00:14:41.049 --> 00:14:45.129 there's not 100% chance that you're going to protect yourself completely, right? 280 00:14:45.169 --> 00:14:47.750 And so if you can avoid traveling to those places, 281 00:14:47.809 --> 00:14:51.929 you should, especially when you're pregnant. As for a healthy 282 00:14:52.009 --> 00:14:54.240 adult with a normal immune system, you know, if you 283 00:14:54.279 --> 00:14:58.259 get Zika virus infection, this is probably unlikely to do 284 00:14:58.299 --> 00:14:59.100 you great harm. 285 00:14:59.580 --> 00:15:02.919 Quick note, 80% of people infected with Zika don't even 286 00:15:03.019 --> 00:15:06.179 show

symptoms. No outward physical signs at all. 287 00:15:06.200 --> 00:15:08.019 Okay, carry on, Desiree. 288 00:15:08.539 --> 00:15:10.929 You... are sick for a few days with fever, you 289 00:15:10.970 --> 00:15:13.289 might have an itchy rash and some red eyes, and 290 00:15:13.309 --> 00:15:16.139 you might feel unwell for a few days, but then 291 00:15:16.179 --> 00:15:19.299 your body clears the virus and you get back to 292 00:15:19.419 --> 00:15:21.820 your normal health after. You know, if you're one of 293 00:15:21.840 --> 00:15:24.779 the unlucky few who has a severe complication from Zika 294 00:15:24.820 --> 00:15:28.250 like Yann Baret, that will, you know, that is, it 295 00:15:28.289 --> 00:15:30.769 can lead to severe disease, but most people are going 296 00:15:30.789 --> 00:15:34.450 to just have the sort of easier week-long, you know, 297 00:15:34.509 --> 00:15:35.669 febrile syndrome from it. 298 00:15:36.690 --> 00:15:39.509 And so if you plan to get pregnant in one 299 00:15:39.669 --> 00:15:42.289 or two or three years, would it be a problem 300 00:15:42.330 --> 00:15:43.710 to be infected with Zika now? 301 00:15:44.230 --> 00:15:47.009 No, I don't believe so. Because if you're a healthy adult, 302 00:15:47.029 --> 00:15:48.750 you're just going to have virus in your bloodstream for 303 00:15:48.789 --> 00:15:52.129 a few days and then it'll go away. You'll clear 304 00:15:52.169 --> 00:15:54.919 the infection and you'll make antibodies that will protect you 305 00:15:54.980 --> 00:15:58.500 from future infections. And so you have actually you've protected yourself. 306 00:15:58.909 --> 00:16:00.789 It's not going to set up shop in your brain 307 00:16:00.830 --> 00:16:03.610 when you get infected and then be around years later 308 00:16:03.649 --> 00:16:04.049 when you want to. 309 00:16:04.029 --> 00:16:04.509 Have a baby. 310 00:16:04.549 --> 00:16:06.590 You will clear that virus within a week or two. 311 00:16:07.509 --> 00:16:09.889 So is it actually a good idea to get Zika 312 00:16:09.970 --> 00:16:12.549 now before you want to get pregnant so you have 313 00:16:12.590 --> 00:16:13.509 some kind of immunity? 314 00:16:13.529 --> 00:16:17.190 That's like when they have a Zika party like they 315 00:16:17.250 --> 00:16:19.850 used to throw chicken pox parties for kids back in 316 00:16:19.870 --> 00:16:25.000 the day. Yeah. Yeah. I wouldn't recommend that. I think 317 00:16:25.039 --> 00:16:30.340 you should protect yourself, avoid travel, and wait for effective 318 00:16:30.759 --> 00:16:35.399 vaccines and therapeutics to come out. I wouldn't suggest that 319 00:16:35.440 --> 00:16:37.179 everybody should throw a Zika party. 320 00:16:37.980 --> 00:16:38.500 Why not? 321 00:16:38.940 --> 00:16:45.200 Even though it's a relatively benign... viral infection when you're 322 00:16:45.220 --> 00:16:47.799 a healthy adult, it's still terrible to get sick for 323 00:16:47.840 --> 00:16:53.679 that long. And I think that the

risk for maybe 324 00:16:53.759 --> 00:16:57.659 severe disease would still be there also. Even though it's small, 325 00:16:57.840 --> 00:16:59.740 it's still a risk. And so at this time, I 326 00:16:59.779 --> 00:17:03.080 think people should just be smart, travel wisely, and protect 327 00:17:03.120 --> 00:17:04.259 yourself from mosquitoes. 328 00:17:05.259 --> 00:17:08.319 And so you think there is really no need to 329 00:17:08.359 --> 00:17:11.380 be concerned about having a Zika infection now and that 330 00:17:11.440 --> 00:17:15.190 infection staying in your body until... even a month if 331 00:17:15.210 --> 00:17:17.400 you want to get pregnant, even a month after infection. 332 00:17:17.579 --> 00:17:21.119 The CDC has come out with recommendations for this. You probably, 333 00:17:21.579 --> 00:17:25.079 you know, want to wait three months after you've had 334 00:17:25.099 --> 00:17:27.789 your Zika virus infection to attempt to getting pregnant. 335 00:17:28.569 --> 00:17:30.750 And given there's quite a bit that we don't know 336 00:17:30.829 --> 00:17:35.029 about Zika, how can they be so confident with that recommendation? 337 00:17:35.970 --> 00:17:37.990 I think they're just looking at the evidence that they 338 00:17:38.029 --> 00:17:41.220 have now and trying to sort of give the best estimates. 339 00:17:42.900 --> 00:17:45.019 I think, you know, the reason why I can feel 340 00:17:45.059 --> 00:17:48.059 confident saying that Zika doesn't sit around, you know, and 341 00:17:48.220 --> 00:17:50.680 isn't ready to come and get your baby three years 342 00:17:50.720 --> 00:17:54.109 later is because, again, your body clears this virus. This 343 00:17:54.170 --> 00:17:57.029 is not a virus like a herpes virus that would 344 00:17:57.390 --> 00:18:00.410 stay with you, stay within your cells, and then rear 345 00:18:00.450 --> 00:18:02.029 its ugly head when you get stressed out, and then 346 00:18:02.049 --> 00:18:04.009 you get a cold sore. It's not that type of virus. 347 00:18:04.089 --> 00:18:05.670 It's not a DNA virus that's going to do that. 348 00:18:05.710 --> 00:18:07.759 This is a virus that's going to come in and, 349 00:18:07.859 --> 00:18:09.819 you know, kill the cells that it infects right then, 350 00:18:09.960 --> 00:18:11.710 and then your body is going to deal with it, 351 00:18:11.859 --> 00:18:15.670 and then it's over. With all the other arboviral infections, 352 00:18:15.730 --> 00:18:19.450 that's exactly what happens. You get the infection, your body 353 00:18:19.509 --> 00:18:22.430 clears the infection, and then you're protected from that infection. 354 00:18:22.549 --> 00:18:24.910 There have been studies that have shown that the people 355 00:18:24.990 --> 00:18:28.190 who have Zika, that you can't even get a positive 356 00:18:28.250 --> 00:18:31.920 test result for Zika virus in your bloodstream if it's 357 00:18:31.960 --> 00:18:34.900 been seven days since your initial fever. It's already gone 358 00:18:34.940 --> 00:18:37.220 out of your bloodstream. So there is evidence to support 359 00:18:37.259 --> 00:18:40.339 that the virus is gone pretty quickly after you get 360 00:18:40.380 --> 00:18:40.960 the infection. 361 00:18:41.839 --> 00:18:42.220 And so. 362 00:18:43.250 --> 00:18:45.569 I think that's why the CDC and others feel pretty 363 00:18:45.609 --> 00:18:48.130 confident saying that, you know, there isn't going to be 364 00:18:48.289 --> 00:18:51.849 any harm to a fetus further on down the line 365 00:18:52.029 --> 00:18:54.450 once you've cleared your Zika virus infection. 366 00:18:55.710 --> 00:18:58.819 Just to clarify, the CDC recommends that women should wait 367 00:18:58.910 --> 00:19:02.539 at least eight weeks after possible exposure to Zika before 368 00:19:02.700 --> 00:19:06.200 trying to get pregnant. But to be sure, Desiree recommends 369 00:19:06.299 --> 00:19:10.900 three months. Now, Desiree acknowledges that right now we don't 370 00:19:10.940 --> 00:19:14.420 have any long-term studies on people infected with Zika, which 371 00:19:14.480 --> 00:19:17.299 means that even though she and other people who study 372 00:19:17.339 --> 00:19:20.440 viruses think that if you are infected with Zika today 373 00:19:20.579 --> 00:19:22.440 and then get pregnant in a couple of months, your 374 00:19:22.480 --> 00:19:26.619 baby will be fine, there is no conclusive evidence of this. 375 00:19:27.539 --> 00:19:30.920 From her and other experts' understanding of these kinds of 376 00:19:30.960 --> 00:19:34.660 viruses in general, though, they do think this is the case. 377 00:19:35.930 --> 00:19:38.779 But there is always a chance that a virus could 378 00:19:38.819 --> 00:19:41.420 break the rules. And we won't know for sure if 379 00:19:41.500 --> 00:19:45.009 Zika is that bad boy until we study it fully. 380 00:19:45.630 --> 00:19:49.009 There are some signs that Zika might not play by 381 00:19:49.029 --> 00:19:52.650 the rules. In July, genetic material from the Zika virus 382 00:19:52.690 --> 00:19:55.329 was found in the mucus of a woman's vagina who 383 00:19:55.549 --> 00:19:59.210 had been infected by Zika. Now, it was found there 384 00:19:59.210 --> 00:20:01.980 11 days after her symptoms set in. At that point, 385 00:20:02.160 --> 00:20:04.279 there was no sign of the Zika virus in her 386 00:20:04.339 --> 00:20:08.180 blood or urine, just the genetic material of Zika in 387 00:20:08.259 --> 00:20:12.890 her vagina. which raised the possibility that Zika may stick 388 00:20:12.950 --> 00:20:16.990 around for longer than expected. And because this is all 389 00:20:17.069 --> 00:20:19.990 so new and when it comes to outbreaks of diseases, 390 00:20:20.069 --> 00:20:24.490 different experts, depending on their speciality, have different perspectives, we 391 00:20:24.549 --> 00:20:28.019 also spoke to Cathy Spong, an obstetrician and acting director 392 00:20:28.059 --> 00:20:31.160 of the National Institute for

Child Health and Human Development. 393 00:20:32.109 --> 00:20:35.269 And we asked her about the CDC's recommendations to wait 394 00:20:35.410 --> 00:20:39.009 eight weeks after possible exposure to Zika before trying to 395 00:20:39.049 --> 00:20:39.670 get pregnant. 396 00:20:40.210 --> 00:20:43.109 If a woman has had Zika, we don't have any 397 00:20:43.230 --> 00:20:48.799 evidence to say that once that time period has passed, 398 00:20:49.319 --> 00:20:55.180 that she should have concerns for a future pregnancy. Then again, 399 00:20:55.259 --> 00:20:56.839 I would say we don't have a lot of data 400 00:20:56.940 --> 00:20:57.460 on it either. 401 00:20:57.480 --> 00:20:58.359 Are you. 402 00:20:58.990 --> 00:21:01.150 happy with the evidence that we have on that at 403 00:21:01.190 --> 00:21:02.390 the moment to give that? 404 00:21:02.410 --> 00:21:04.250 This is the best information we have available. 405 00:21:05.470 --> 00:21:06.630 How confident are you in it? 406 00:21:07.690 --> 00:21:09.359 It's the best information we have available. 407 00:21:10.500 --> 00:21:11.140 Kathy. 408 00:21:11.160 --> 00:21:18.539 I mean, the CDC has, these are the guidance based 409 00:21:18.599 --> 00:21:20.539 on the best information we have available. 410 00:21:20.799 --> 00:21:20.940 Yeah. 411 00:21:22.240 --> 00:21:24.569 Depending on your perspective on life, you can take the 412 00:21:24.670 --> 00:21:27.309 unknowns and amplify them in your head or. 413 00:21:28.789 --> 00:21:29.849 You can underplay them. 414 00:21:29.910 --> 00:21:33.049 But when it comes to disease, we tend to overplay them. 415 00:21:33.589 --> 00:21:36.609 So, I mean, there's always unknowns in everything we do. 416 00:21:37.529 --> 00:21:41.450 And so I think, yes, this is an unknown that 417 00:21:41.509 --> 00:21:46.849 is a little more, a little heightened in the sense 418 00:21:46.950 --> 00:21:49.930 that this is something that is new that we don't 419 00:21:49.990 --> 00:21:52.990 have a lot of data on. That said, it's simply 420 00:21:53.170 --> 00:21:55.029 one of the many unknowns in pregnancy. 421 00:21:59.190 --> 00:22:02.089 After the break, Zika has been around for a very 422 00:22:02.190 --> 00:22:05.529 long time. So why is it spreading and causing these 423 00:22:05.609 --> 00:22:16.670 heartbreaking symptoms now? Hey, it's Wendy from Science Versus, and 424 00:22:16.690 --> 00:22:18.930 I want to tell you about a podcast that I. 425 00:22:18.890 --> 00:22:20.309 Love, Science Friday. 426 00:22:20.509 --> 00:22:23.029 They cover all sorts of amazing things in the weird 427 00:22:23.069 --> 00:22:27.119 and wonderful world of science, from how concussions affect our 428 00:22:27.160 --> 00:22:30.220 brain to the inner secrets of a snake with a 429 00:22:30.319 --> 00:22:32.839 spider on its tale. It's a lot of news that 430 00:22:32.900 --> 00:22:35.349 you can use and some that you can't, but you're 431 00:22:35.369 --> 00:22:36.210 going to love anyway. 432 00:22:36.450 --> 00:22:39.630 It's hosted by Ira Flato and Flora Lichtman. 433 00:22:39.789 --> 00:22:42.490 Who is an old friend of the show and loves 434 00:22:42.569 --> 00:22:43.990 a pun as much as we do. 435 00:22:44.009 --> 00:22:47.819 Science Friday is on every day wherever you get your podcasts. 436 00:22:50.500 --> 00:22:50.960 Welcome back. 437 00:22:51.279 --> 00:22:55.059 So remember when those scientists first identified Zika in Uganda 438 00:22:55.279 --> 00:22:57.490 in 1947 by putting the monkeys up in. 439 00:22:57.440 --> 00:23:01.049 The tree to get bit by mosquitoes? Well, if we've 440 00:23:01.130 --> 00:23:01.950 known about. 441 00:23:01.789 --> 00:23:05.519 This disease since 1947, a disease that we just heard 442 00:23:05.619 --> 00:23:08.619 can do some really scary things to us, especially in 443 00:23:08.660 --> 00:23:13.119 developing babies, why are we just starting to notice this 444 00:23:13.180 --> 00:23:14.240 disease now? 445 00:23:15.299 --> 00:23:16.200 How did we miss it? 446 00:23:17.160 --> 00:23:20.430 To help us answer this question, we turned to Andrew Haddow, 447 00:23:20.490 --> 00:23:23.990 a researcher at the United States Army Medical Research Institute 448 00:23:24.309 --> 00:23:29.710 for Infectious Diseases. Now, Andrew's grandfather just happens to be 449 00:23:29.890 --> 00:23:34.640 Alexander Haddow, one of the first scientists to isolate Zika 450 00:23:34.940 --> 00:23:35.569 back in the 1940s. 451 00:23:35.759 --> 00:23:38.740 The first time I heard about Zika was probably when 452 00:23:38.759 --> 00:23:41.140 I was about three or four years old from my 453 00:23:41.220 --> 00:23:44.099 father during my bedtime stories. 454 00:23:44.759 --> 00:23:48.210 And before we talk to Andrew about why we underestimated Zika, 455 00:23:48.930 --> 00:23:51.490 you need to know that he has carried on his 456 00:23:51.569 --> 00:23:56.470 grandfather's work by making another really big discovery about Zika. 457 00:23:57.200 --> 00:24:01.000 a discovery made in the late 2000s in Senegal. And 458 00:24:01.039 --> 00:24:04.279 it all started when his buddy Kevin, who's also a scientist, 459 00:24:04.839 --> 00:24:07.779 was telling Andrew about this weird illness that he and 460 00:24:07.799 --> 00:24:11.509 his mate got when they were working with mosquitoes. I 461 00:24:11.529 --> 00:24:12.829 was imagining it was over beer. 462 00:24:12.900 --> 00:24:15.490 It was. It was over a beer. It was over 463 00:24:15.549 --> 00:24:19.769 a beer. Yeah, kind of on a veranda looking out 464 00:24:19.849 --> 00:24:21.670 over a river. So I said, you know, Kevin, it 465 00:24:21.710 --> 00:24:25.890 sounds like you have both maybe had Zika virus. We 466 00:24:25.910 --> 00:24:28.950 need to test your blood. And then he kind of 467 00:24:28.990 --> 00:24:31.410 leans back in his chair and just says, well, there's 468 00:24:31.470 --> 00:24:35.730 something else. And I was just like, you know, what else? Because,

469 00:24:35.769 --> 00:24:37.549 I mean, it's just kind of like, what else could 470 00:24:37.569 --> 00:24:40.930 there be? And he's like, the other investigator's name was 471 00:24:41.009 --> 00:24:44.519 Brian Foy. And so he says, well, Brian, Brian's wife 472 00:24:44.579 --> 00:24:47.559 came down with the same signs and symptoms after he 473 00:24:47.599 --> 00:24:49.920 got back. And it's just like, what? And I mean, 474 00:24:50.599 --> 00:24:53.380 all of this together just kind of pointed to the 475 00:24:54.220 --> 00:24:57.579 likelihood of a sexual transmission event. There were some other 476 00:24:58.039 --> 00:25:01.099 signs and symptoms that pointed to the possibility... Like the 477 00:25:01.140 --> 00:25:03.119 fact they had sex? I'm sorry? 478 00:25:03.339 --> 00:25:04.460 Like the fact they had sex? 479 00:25:04.940 --> 00:25:08.680 Yes. Brian had noticed that there had been blood in 480 00:25:08.720 --> 00:25:11.710 his semen and that he had had... His prostate was 481 00:25:11.789 --> 00:25:15.769 inflamed and his wife came down with classic... What we 482 00:25:15.789 --> 00:25:20.970 would kind of call classic Zika signs and symptoms, fever, rash, etc. So. 483 00:25:23.680 --> 00:25:25.789 Just was kind of one of those things like, wow. 484 00:25:25.920 --> 00:25:27.849 I mean, I said, yeah, we really have to get your, 485 00:25:28.630 --> 00:25:30.869 her blood also. We need to, you know, we need 486 00:25:30.890 --> 00:25:32.950 to test this. And I said, you know, I really 487 00:25:33.009 --> 00:25:35.029 think that it's Zika. 488 00:25:35.190 --> 00:25:38.970 Because is this, is this really uncommon for this sort 489 00:25:38.990 --> 00:25:39.859 of virus? 490 00:25:40.170 --> 00:25:45.900 Yes. So before this, this diagnosis, there were no reports, 491 00:25:46.759 --> 00:25:50.680 to my knowledge, of sexual transmission of an arbovirus in 492 00:25:50.700 --> 00:25:55.630 the literature. the closest was a report of Japanese encephalitis 493 00:25:55.670 --> 00:26:00.359 virus in the semen of boars. So this is just 494 00:26:00.420 --> 00:26:05.720 kind of way out there as things go. And so, 495 00:26:06.319 --> 00:26:08.940 you know, it was met with, I think I can say, 496 00:26:09.130 --> 00:26:11.650 a lot of skepticism in our community. 497 00:26:12.089 --> 00:26:15.910 Other studies have recently confirmed what Andrew first discovered, that 498 00:26:15.990 --> 00:26:18.829 Zika can be found in semen, and it stays in 499 00:26:18.890 --> 00:26:22.339 semen longer than it does in blood. In one report, 500 00:26:22.420 --> 00:26:25.740 a woman got infected with Zika through unprotected sex about 501 00:26:25.799 --> 00:26:29.339 a month after her partner showed symptoms of Zika infection. 502 00:26:29.960 --> 00:26:32.740 So that means the virus was alive in her partner's 503 00:26:32.779 --> 00:26:36.380 semen for at least that long. As a result, the 504 00:26:36.400 --> 00:26:40.839 World Health Organization recommends that men who travel to Zika-infected 505 00:26:40.980 --> 00:26:44.900 areas wait six months before having unprotected sex. 506 00:26:46.039 --> 00:26:49.109 Yep, six months. Got it? 507 00:26:50.230 --> 00:26:53.130 Now, Andrew doesn't just probe his mate's sex life for 508 00:26:53.170 --> 00:26:56.289 his research. He's also been studying the genetics of the 509 00:26:56.329 --> 00:26:57.849 Zika virus over time. 510 00:26:58.109 --> 00:26:59.819 So we had a lot of questions for him. 511 00:27:00.650 --> 00:27:04.400 First off, though, why did this outbreak with the microcephaly 512 00:27:04.519 --> 00:27:07.220 and the paralysis happen now? 513 00:27:07.900 --> 00:27:12.160 Maybe the virus could have always done these things, but 514 00:27:12.440 --> 00:27:14.920 first of all, they weren't detected. So I think as 515 00:27:14.960 --> 00:27:17.420 we're seeing more cases, we're just getting a better understanding 516 00:27:17.460 --> 00:27:20.349 of really what the virus is capable of doing. It's 517 00:27:20.410 --> 00:27:22.470 not that it wasn't doing it in the past. It 518 00:27:22.509 --> 00:27:26.490 may literally just be there weren't enough people studied to 519 00:27:26.549 --> 00:27:30.029 really know. The other part is in these areas where 520 00:27:30.089 --> 00:27:34.849 Zika virus is endemic, historically, women or girls would have 521 00:27:35.009 --> 00:27:37.660 likely been infected at a very young age before they 522 00:27:37.740 --> 00:27:41.700 ever even reached puberty. And what that means is they 523 00:27:41.740 --> 00:27:45.079 basically would have been immune when they were adults and 524 00:27:45.119 --> 00:27:48.430 when they were getting pregnant and having children. And that 525 00:27:48.470 --> 00:27:54.480 may also be a reason why we didn't see microcephaly 526 00:27:54.519 --> 00:27:59.119 in those regions before now. Honestly, I think that we 527 00:27:59.220 --> 00:28:03.730 owe a lot to a group of physicians in Brazil 528 00:28:04.210 --> 00:28:09.210 for really pushing the microcephaly, at the time it was 529 00:28:09.250 --> 00:28:14.599 a hypothesis, forward and really bringing widespread attention to this issue. 530 00:28:15.240 --> 00:28:18.650 At first, it was, I'll tell you, it was met 531 00:28:18.690 --> 00:28:22.150 with a lot of skepticism in the scientific community. 532 00:28:22.609 --> 00:28:25.029 Why was there so much skepticism? 533 00:28:26.150 --> 00:28:30.130 Well, I think what happens is we all get tunnel vision. And, 534 00:28:30.150 --> 00:28:33.269 you know, this is what the virus does, and that's 535 00:28:33.329 --> 00:28:35.910 all it does. And it was the same with what 536 00:28:35.950 --> 00:28:39.430 we know now, that the case of sexual transmission, that 537 00:28:39.490 --> 00:28:43.490 was met with skepticism. Then you have Guillain-Barre syndrome, met 538 00:28:43.509 --> 00:28:47.930 with skepticism, and microcephaly. met with skepticism, you know, we 539

00:28:47.990 --> 00:28:52.650 sometimes we get so used to what we would maybe 540 00:28:52.670 --> 00:28:56.109 the norm that we forget that things change and that 541 00:28:56.130 --> 00:28:59.529 we always have to be cognizant that these viruses aren't 542 00:28:59.549 --> 00:29:03.380 an evolutionary arms race and they are trying to adapt 543 00:29:03.779 --> 00:29:07.779 to infect more hosts. So we have to be cognizant 544 00:29:07.900 --> 00:29:10.720 just because something hasn't done anything for, you know, 70 545 00:29:10.720 --> 00:29:13.720 years that doesn't mean that it can't do it in 546 00:29:13.759 --> 00:29:14.220 the future. 547 00:29:14.240 --> 00:29:16.380 Do you think it's possible that the Zika virus is 548 00:29:16.440 --> 00:29:19.160 mutating in some way to make it easier to infect 549 00:29:19.259 --> 00:29:20.220 big populations? 550 00:29:21.200 --> 00:29:23.769 So there's just a lot we don't know about the virus. 551 00:29:23.809 --> 00:29:26.710 We're learning new things almost every week. But what I 552 00:29:26.789 --> 00:29:31.470 can say is it appears that the virus is overall 553 00:29:31.569 --> 00:29:32.369 pretty stable. 554 00:29:32.890 --> 00:29:37.029 So scientists have started tracking how Zika has changed genetically 555 00:29:37.190 --> 00:29:40.319 since it was first detected in 1947. And they have 556 00:29:40.480 --> 00:29:44.799 found minor differences in its genetic code. But so far, 557 00:29:44.880 --> 00:29:47.920 it's still not clear if Zika is evolving to become 558 00:29:48.099 --> 00:29:51.599 more dangerous necessarily, or if it's basically the same old 559 00:29:51.680 --> 00:29:54.480 virus that just happened to find a continent of people 560 00:29:54.539 --> 00:29:59.289 to make sick for the very first time. Okay, so 561 00:29:59.309 --> 00:30:02.349 what have we learnt? First, where did Zika come from? 562 00:30:03.009 --> 00:30:05.849 Researchers first found it in Africa and it's been there 563 00:30:05.930 --> 00:30:09.990 for probably thousands of years. Two, what happens when you 564 00:30:10.009 --> 00:30:13.720 get infected? There's rashes and fevers and while there are 565 00:30:13.759 --> 00:30:18.480 some complications, most of the time the disease is pretty mild. 566 00:30:18.559 --> 00:30:21.940 In fact, 80% of people who get infected don't even 567 00:30:22.039 --> 00:30:26.369 show symptoms. But when you are pregnant, the virus can 568 00:30:26.430 --> 00:30:29.589 make a beeline for the foetus. And we're still trying 569 00:30:29.630 --> 00:30:33.789 to work out the full consequences of this. Third, how 570 00:30:33.849 --> 00:30:36.049 worried should you be if you live or are travelling 571 00:30:36.089 --> 00:30:40.720 to a Zika-affected part of the world? Well, if you're 572 00:30:40.740 --> 00:30:43.039 not pregnant, you're not planning on getting pregnant and you're 573 00:30:43.059 --> 00:30:47.240 not planning on making anyone else pregnant anytime soon, there's 574

00:30:47.299 --> 00:30:50.890 probably no need to be that worried. But if you 575 00:30:51.029 --> 00:30:54.589 are thinking of getting pregnant, this is a real concern. 576 00:30:55.150 --> 00:30:58.450 Because we currently don't know the chance that your baby 577 00:30:58.509 --> 00:31:04.390 will have defects if you are infected. And finally, why 578 00:31:04.470 --> 00:31:08.720 has this new ugly side of Zika reared its head now? 579 00:31:10.119 --> 00:31:11.900 We don't exactly know. 580 00:31:12.299 --> 00:31:14.740 One theory is that people in parts of Africa where 581 00:31:14.759 --> 00:31:17.880 the virus has been around for ages are now immune 582 00:31:17.940 --> 00:31:20.259 to it. And it was only when the virus hit 583 00:31:20.319 --> 00:31:23.740 a large population that has never been exposed before that 584 00:31:23.839 --> 00:31:30.210 trouble struck. So now that we have this problem, the 585 00:31:30.230 --> 00:31:33.779 big question is, of course, how to stop it. 586 00:31:34.480 --> 00:31:36.440 There are a few things that scientists are working on. 587 00:31:36.680 --> 00:31:39.220 They're seeking out a vaccine and they're also trying to 588 00:31:39.279 --> 00:31:47.230 lower mosquito populations, potentially by releasing genetically modified mozzies. Male 589 00:31:47.369 --> 00:31:51.210 mosquitoes have been specifically crafted so that when they bonk 590 00:31:51.470 --> 00:31:56.170 female mosquitoes, the offspring will die young. That is, the 591 00:31:56.210 --> 00:31:58.750 mozzie babies won't be able to make it to adulthood 592 00:31:58.809 --> 00:32:02.720 and won't be able to create more mozzie babies. Theory 593 00:32:02.759 --> 00:32:06.019 goes that if you release enough of these genetically modified 594 00:32:06.259 --> 00:32:10.920 dud mosquitoes, the population of mozzies will drop to hopefully 595 00:32:10.940 --> 00:32:15.009 the point where the diseases won't spread anymore. Small trials 596 00:32:15.069 --> 00:32:18.690 conducted by the company that makes these mosquitoes, Oxitec, found 597 00:32:18.769 --> 00:32:22.250 that releasing these guys could reduce the mozzie population by 598 00:32:22.289 --> 00:32:27.329 around 90%. In August, the FDA approved plans to release 599 00:32:27.390 --> 00:32:30.569 them into Florida, but the community over there will have 600 00:32:30.609 --> 00:32:34.740 to decide whether they want it or not. Thing is, 601 00:32:35.440 --> 00:32:38.519 even if we can get rid of 90% of the mosquitoes, 602 00:32:38.680 --> 00:32:43.279 there are still that cheeky 10% hanging around. Plus, the 603 00:32:43.319 --> 00:32:47.099 virus can spread while we are having sex. So probably 604 00:32:47.200 --> 00:32:49.650 the only way to protect us against Zika in the 605 00:32:49.730 --> 00:32:54.910 long term is to develop a vaccine. As of 2016, 606 00:32:54.910 --> 00:32:58.269 29 different Zika vaccines were in development around the world. 607 00:32:58.529 --> 00:33:00.450 That's according to the World Health Organization. 608 00:33:00.849 --> 00:33:04.579 One trial started in humans back in June, another in August. 609 00:33:04.700 --> 00:33:07.119 But right now, scientists are just checking to see if 610 00:33:07.140 --> 00:33:09.359 the vaccine causes any bad side effects. 611 00:33:09.890 --> 00:33:12.099 That's what happens in the first batch of volunteers. 612 00:33:12.960 --> 00:33:16.119 Even with huge international efforts to make a good vaccine 613 00:33:16.220 --> 00:33:19.839 as soon as possible, the National Institutes of Health estimates 614 00:33:19.960 --> 00:33:26.670 that the earliest date we'll see a vaccine is in 2018. So, 615 00:33:27.569 --> 00:33:30.470 what can you do right now if you live in 616 00:33:30.509 --> 00:33:35.579 an area impacted by Zika? Scientists recommend that you try 617 00:33:35.640 --> 00:33:39.730 to keep mosquitoes away the best way you can. And 618 00:33:39.769 --> 00:33:43.069 that means getting rid of open water in containers or 619 00:33:43.109 --> 00:33:46.809 blocked drains. That's what the mozzies use to breed. Also, 620 00:33:46.890 --> 00:33:49.849 perhaps sleep beneath a net. You can pop on your 621 00:33:49.930 --> 00:33:53.619 air conditioner because mozzies don't like the cold. Also, wear 622 00:33:53.660 --> 00:33:57.779 long sleeves and use bug spray. OK, that's what we 623 00:33:57.819 --> 00:34:01.869 know for now. The research continues... as it always does, 624 00:34:02.230 --> 00:34:07.730 because this is science, and this was Science vs Zika. 625 00:34:12.889 --> 00:34:15.860 This episode has been produced by Diane Wu, Heather Rogers, 626 00:34:15.940 --> 00:34:19.739 Caitlin Kenney, Shruti Ravindran, and our senior producer is Caitlin Sori. 627 00:34:20.440 --> 00:34:23.760 Edited by Annie Rose Strasser and fact-checked by Michelle Harris. 628 00:34:24.320 --> 00:34:27.429 Sound design and music production by Matthew Boll, mixed by 629 00:34:27.510 --> 00:34:29.190 Martin Peralta and Bobby Lord. 630 00:34:29.750 --> 00:34:33.579 Music written by Martin Peralta and Bobby Lord. For key references, 631 00:34:33.719 --> 00:34:34.719 head to our webpage. 632 00:34:35.260 --> 00:34:39.340 Next week, we're tackling forensic science. On CSI, it looks 633 00:34:39.500 --> 00:34:40.139 so easy. 634 00:34:40.639 --> 00:34:41.719 But how much can you. 635 00:34:41.679 --> 00:34:45.210 Really trust the science that gets presented in courtrooms? 636 00:34:45.909 --> 00:34:47.789 I'm Wendy Zuckerman. Back to you next time.