World Policy Journal caught up with prize-winning author Sonia Shah to discuss the threat of global pandemics. An investigative science journalist, Shah’s work has appeared in numerous publications, including The New York Times, The Wall Street Journal, Foreign Affairs, Scientific American, and others. Her TED talk, "Three Reasons We Still Haven’t Gotten Rid of Malaria," was seen online by over 1 million people. Shah is the author most recently of Pandemic: Tracking Contagions from Cholera to Ebola and Beyond, a historical investigation of pandemics' rise. Her other titles include The Fever, which was long-listed for the Royal Society’s Winton Prize, The Body Hunters, and Crude, among others.
WORLD POLICY JOURNAL: In your book, Pandemic: Tracking Contagions from Cholera to Ebola and Beyond, published in February 2016, you track how a new pandemic could arise in the future by charting how other pathogens like cholera developed. Almost immediately following the publication of your book, the World Health Organization declared the Zika virus to be a global health emergency. How does this affirm the arguments you make in your book?
SONIA SHAH: Zika is a great example of everything that I talked about in my book. Over the past 50 years we have had over 300 infectious pathogens that have either newly emerged or reemerged in places where they have never been seen before. Zika is really just the latest. We have had Ebola in West Africa, SARS in South China in 2003, and another new one called MERS or the Middle East Respiratory Syndrome, which came out in the Middle East a couple of years ago. We also have new kinds of avian influenza, including one that hit North America last year and caused the biggest epidemic of animal disease in United States history. There are also new kinds of mosquito-borne viruses. We have Chikungunya virus, which is new in the Americas. Dengue is also spreading very rapidly. So there is really a trend of these pathogens emerging and being driven into human populations in new ways. Zika is really a prime example of that.
WPJ: How did Zika become such a global threat?
SS: We have had the Zika virus since the 1940s and probably before that. It was mostly present in the equatorial forests of Asia and Africa. It didn’t cause much human disease then because it was carried in the forests by a mosquito that bit mostly animals, not people. Then, in 2013, it boarded an airplane and got into Brazil in one of these chance events. In Brazil, you have these huge urban populations that are getting bitten by urban mosquitoes all of the time. It is the same genus of mosquitoes that carry Zika virus in Africa and Asia. This species just bites people exclusively and lives around human garbage in these cities. Once it got into that system in Brazil, it was able to explode.
Zika virus actually doesn’t cause much disease in adults. You need to have a huge explosion of infections to see the rare complications of Zika virus, which is that it causes congenital problems in unborn babies. These problems are very serious, dangerous, and life threatening. It is probably causing miscarriages as well as stillbirths. It wasn’t until now that we are able to see that Zika virus has this horrible impact on unborn babies. It is a very cryptic virus because it can spread very far due to not showing symptoms. Eighty percent of the people with Zika don’t have any symptoms at all. For the 20 percent who do have symptoms, their symptoms are so mild that it could easily be confused with something else or land up just being ignored. Meanwhile, that person was infecting other people and mosquitoes. We also now know that Zika is a sexually transmitted disease. That means that the virus can travel even farther beyond the reach of where mosquitoes can travel. Somebody from Rio can take a plane to Florida and have sex with multiple partners there, causing the virus to spread in America.
WPJ: What was most surprising about your research on the history of pathogens and pandemics?
SS: One of the things I looked at is how people respond to new pathogens. My previous book was about malaria and one thing that is really interesting about malaria is that people who experience problems with malaria consider it a normal part of life. It becomes normalized. This goes a long way to explaining why we have so much malaria in the world despite it being completely curable. So even though malaria takes a huge number of lives every year, people who are regularly exposed to it think of it as normal. That diminishes the urgency of taking steps to get rid of it.
You also see this in the way that we respond to new pathogens today, like how we responded to Ebola in 2014, Dengue in Florida in 2009, or Zika right now. Our response veers between panic and denial. We react on these two opposite poles. Both reactions come from the same source, which is that we think of these contagious diseases and epidemics as risks that we are powerless to control. Unless there is a drug or vaccine, we don’t have control. And because these are all new pathogens that we haven’t seen before or at least haven’t seen very much of before, we don’t generally have drugs or vaccines for them. So we respond as though we are powerless in the face of these pathogens. It is sort of like how people respond to the inevitability of their own death. We respond to new diseases and contagions in the same way because we feel powerless against them without the shield of medicine. What I found in writing this book and looking at the history of pandemics and how contagions spread through human populations is that in fact we are not powerless. There are a lot of steps that we can take to prevent these pathogens from spreading. Really, every step of the way in building a pandemic is human activity.
WPJ: Do you think that Americans are generally misinformed about the risks of diseases like Zika and other global contagions? How can we make changes on the education level?
SS: We need more science literacy. We don’t have enough science literacy in this country and that is a huge missing piece. I think for several decades now, we have disengaged from health and medicine as a society because we have thought about it as something for the experts to deal with. We wait to pick up our prescriptions at the drug store and that is the extent of our engagement with how diseases function, spread, and emerge. That is what really needs to change. We have become empowered as patients by taking control of our health needs in the doctor’s office, but we need to become empowered as a society when we are looking at epidemics and contagions. It is not just something that we can wait around for the experts to take care of; we really need to engage. What are the conditions that we live in that allow these pathogens to emerge and spread among us? These are microbes that have no independent locomotion. In order for these microbes to cause epidemics, they rely entirely on human action.
WPJ: Can you talk about the link between human behavior and the spread of contagions?
SS: Each pathogen is very different. It is going to have a unique path, but there are definitely some commonalities. A lot of these new pathogens are coming out of animals’ bodies. About 60 percent come out of animals and 70 percent of those that come out of animals come out of wildlife. The reason that is happening is that people are coming into new kinds of contact with wild animals. That is because we are destroying a lot of their habitat. When we destroy and invade their habitat, the ones that remain move in ever closer with us. So when we cut down all of the trees where the bats live, the bats come into our gardens and homes, bringing us in new kinds of contact with these animals. So if you pick up a piece of fruit that is under a tree that has been sucked at by a fruit bat and you get some of that saliva on your hand and put your hand in your mouth, you have created a bridge for the microbes that live in the bat to come into the human body. That is how we are getting a lot of these new diseases.
Ebola is a great example that came out of fruit bats and into the human population, ultimately adapting to us. We are amplifying these things in our cities. Ebola for example had never infected a place that had more than a few hundred thousand inhabitants before 2013. Well, then at the end of 2013, it came out of a small village in Guinea and within weeks affected three capitol cities with a combined population of nearly three million. That is because the entire human population is becoming urbanized. So this process that started in the 19th century is reaching its peak now. By 2030, the majority of people will live in giant cities. So, there is a massive urban expansion especially in tropical areas. Ebola took advantage of that. Zika is taking advantage of it right now in the Americas. Once it was able to come to the Americas, it reached all of these rapidly growing cities and lots of slum areas, as well as an urban mosquito that specializes in biting humans and lives in human garbage. So when Zika entered into the urban mosquito, you got this huge explosion of that virus.
Urbanization plays a big role. It is not just humans. We are also urbanizing our animals and livestock in the form of factory farms where we have these farms with a million or more animals crammed in really closely together. These animals are living and breathing on each other, but they are also very much surrounded by their own waste and each other’s waste. That creates a great opportunity for pathogens to amplify. Then, of course, we carry these things around on the airplanes, allowing them to reach not just a few cities and towns but hundreds of cities and towns with hundreds of thousands of connections between them. So if a pathogen pops up in a remote part of the world, it can very rapidly reach vulnerable populations anywhere on the planet.
WPJ: Getting back to your point about human’s reliance on animals, we see similar challenges with issues like climate change, where meat production contributes to a significant proportion of global emissions. Do you think Americans need to make an effort to curb our reliance on animals and animal products? Is this becoming more of a reality?
SS: I think we do for a number of reasons and not just because of contagions, but that is one additional reason that we need to do that. But yes, climate change is already changing the landscape of disease. So allowing ticks or mosquitoes to move into higher altitudes allows these disease-killing vectors to reach new populations. It also means that they might be leaving other places. It is not just that there is going to be more of them. They are actually changing where they are going to go. What that means is that they are going to reach populations that don’t have immunity to them. When diseases are already in the same place, populations get exposed and you eventually have less disease over time. When diseases move, you often get big outbreaks.
WPJ: It is an election year in the United States. Do you see enough attention being devoted to public health concerns?
SS: I think that the way we tend to cope with infectious disease is after the fact. We still don’t have a way of looking at true prevention. Even when we are talking about preparing for the next epidemic or preventing the next pandemic, what we are really talking about is first-response. We are really talking about making sure our hospitals are ready. Let’s stockpile drugs and vaccines. Those things are good, but when you are doing that, the epidemic has already started. So we need to move the whole conversation backwards to look at true prevention. What are the primary causes of these outbreaks? We need to change those. I don’t think we have even started to talk about that as a society or within the medical establishment. There are a few small groups that are trying to look at true prevention more carefully, but they are nowhere near the mainstream.
WPJ: What is your view of organizations like the World Health Organization? Is it effective?
SS: I think that the promise of the World Health Organization is wonderful, but in fact, it is a very small agency. They have a tiny budget and it is completely dependent on the political climate. It only controls a fraction of its own budget because it has been progressively underfinanced with member countries coming up with policies of zero growth. So the budget has gotten smaller and smaller over time and the WHO has had to make that up through private donations. You know, donations that come with strings attached. What that means is that the WHO is not an independent organization anymore. So, it is a struggle. The WHO can actually only go to places where it is invited to go. It can only take action at the mercy of the local political establishment. It is a very, very hampered organization in that way.
WPJ: Where do you think the next global pandemic will come from? Can we pinpoint which pathogens pose the most significant health concern?
SS: I don’t think we can predict which one. Zika is a great example of why not. Zika was just something that wasn’t on the charts. It wasn’t even thought about as a contender for major global outbreaks, and yet here it is causing a pandemic. These aren’t things that you can very well predict. That has been clearly shown. That said, the experts generally worry about a novel form of avian influenza. We have seasonal pandemics and flus every year. A lot of people die from these seasonal pandemics costing the economy huge amounts of money. And those are flu viruses to which human populations have some immunity. New kinds of avian influenza, if able to spread among us as effectively as the seasonal pandemics, will be troublesome because we have much less immunity to them. Even with a slightly higher death rate, we could have huge numbers of deaths. So, novel forms of avian influenza are probably what most virologists are going to stay up late at night worrying about.
Another category of pathogens that really scares experts is antibiotic-resistant bacteria. We have progressively gotten more and more resistant forms of bacteria. There are also plasmids, which are genes that can move into bacteria, including one that just came up this year which allows bacteria to resist our very “last resort” drug called colistin. That drug-resistant bacteria came out of pigs in China and is now spreading. What would happen is that when one of these drug-resistant genes gets into a bacteria that actually causes a lot of human disease, it would really be the end of medicine, with common infections, small wounds, and small injuries becoming life-threatening due to the risk of untreatable infections. So, drug-resistant bacteria is going to change the face of medicine. We do a lot of elective surgeries right now that aren’t life and death. You wouldn’t do any of those, because it wouldn’t be worth the risk of an untreatable infection.
WPJ: What is next for you?
SS: I am interested in looking at the deep history of epidemics and how that seems to be shaping our health risks today. I am also working on a new project looking at migration, climate change, and infectious diseases, especially what is going on in Greece and the rest of Europe.
This interview was conducted, edited, and condensed for clarity by Ashley Chappo.
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[Photo courtesy of Sonia Shah]