DQ Blog

January 2016: Why Zika Is This Year’s Scary Virus

from National Geographic online

Scary new viruses emerge abruptly in our modern world, provoking stark headlines and demands for bold government action—but in most cases the causes are complex and have developed, unnoticed, over years or decades. That’s true again for Zika, a virus unknown to most people until recent days, and now suddenly the subject of somber warnings from the Centers for Disease Control and Prevention and the World Health Organization, which announced on Thursday that the virus is “spreading explosively.” The alarm stems from an epidemic of birth defects in Brazil, which may be linked with Zika virus infection of mothers during pregnancy. Amid this furor, it’s worth distinguishing fact from supposition and placing the Zika phenomenon in a broader context.

20487 lores400This is a transmission electron micrograph (TEM) of Zika virus, which is a member of the family Flaviviridae. Virus particles are 40 nm in diameter, with an outer envelope, and an inner dense core. The arrow identifies a single virus particle. Photo by Cynthia Goldsmith.This virus was first isolated in Uganda in 1947, within a small enclave called Zika Forest, near the west shore of Lake Victoria, where researchers from the Rockefeller Foundation were studying yellow fever. Ironically, the earliest known victim of Zika virus infection in Africa was an Asian macaque—a rhesus monkey, set out in a cage in a treetop as bait for the mosquitoes that carry yellow fever virus. Instead of that virus, its blood yielded this new thing, dubbed Zika. The virus had never been seen before, but it had probably lurked chronically in African monkeys, or some other native reservoir, for millennia. The same virus later turned up, in the same forest, within mosquitoes of the Aedes genus, and those mosquitoes are now identified as vectors of Zika, transmitting the virus from host to host when they bite.

Eventually it was found infecting people, too, not just in Africa but also in Asia—from Senegal to Cambodia, in fact, a wide range throughout which Aedes mosquitoes reside. The symptoms, such as headache, fever, a rash, bloodshot eyes, were generally mild.

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One year ago at this time, the Ebola outbreak in West Africa was just emerging from a lull, a falsely reassuring hiatus, like the “phony war” that settled over Europe in 1939, after Hitler’s invasion of Poland.  During early April, 2014, there was optimism among health officials that control measures were working--in Guinea, where it had all IMG 3061begun, and in the two other affected countries, Liberia and Sierra Leone; there was guarded confidence that those efforts would soon bring the outbreak to an end.  Some of the expert responders from overseas went home, to the CDC in Atlanta and elsewhere.  Then in late May came a disconcerting surge.  The incidence of new cases rose abruptly.  Traditional funeral practices and other factors allowed the virus to spread; response efforts, facilities, and supplies turned out to be insufficient.  Sick people were traveling—across borders among the three countries, and from the countryside to towns.  By mid-June, the disease had reached Liberia’s capital, Monrovia.  You know what happened next: Instead of an end, there was a geometrical getaway, an explosion of cases, as the outbreak became an epidemic.

As of yesterday, the official count from the World Health Organization is this: 27,237 cases and 11,158 deaths.

Furthermore, the epidemic still hasn’t ended—though it has fallen below the attention threshold for most news media outside of Africa.  Liberia is presently free of Ebola cases, but Guinea and Sierra Leone are not.  In fact, during two consecutive weeks now there have been slight increases in the new case counts for Guinea and Sierra Leone.  That unnerving little trend, plus the continuing occurrence of puzzling new cases for which the source (who infected whom?) can’t be identified, “highlights the challenges” (in the careful language of the WHO) of bringing this whole gruesome chain of events to a close.

Another unnerving fact is that there’s still so much about Ebola virus disease that we don’t understand.  At the top of that list of unknowns is the identity of the reservoir host—the creature in which the virus abides, quietly, inconspicuously, when it’s not causing devastation among humans.

IMG 3006Thirty-nine years

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As the epidemic of Ebola continues to ravage three West Africa countries, and to frighten people around the world, many scientific  questions about this disease and the ghastly microbe that causes it remain unanswered.  One of those is: What’s the reservoir host of Ebola virus, the creature in which it lives secretively over the long term?  Fabian Leendertz works on that question, and in December he published a preliminary study describing a new hypothesis.  Because I’m at work on a feature story about the reservoir question and Leendertz’s work, National Geographic asked me to write a brief post for its online news about the newly released study.

You can read that post here.

The full story, with text by me and photographs by Pete Muller, will appear in the July 2015 issue of National Geographic.

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IMG 3066The 2014 epidemic of Ebola virus disease in West Africa is unlike any Ebola event ever seen before. In fact, as of this writing, it’s already ten times larger in terms of case fatalities—ten times more punishing to Africans, ten times more scary and befuddling to people around the world—than any single outbreak of an ebolavirus (there are five kinds) during the previous known history of the disease. The peculiarly unfortunate circumstances that allowed this outbreak to simmer for months and then explode in the three countries first affected, and especially in Liberia, include weakened governance after decades of civil turmoil, inadequate health-care infrastructure, shortage of trained health-care workers and simple barrier-nursing supplies, population density and poverty in the capital cities, suspicion of Western medicine, and traditional funerary practices. Those factors, and the progress of the epidemic, have been charted in some of the best of the news coverage, including this story by Canadian reporter Helen Branswell, and this one from a team at The Washington Post.

I value such news reporting as much as anyone, but my own role as a writer is different; I cover science and science history at greater length and slower speed. Still, as the epidemic became more severe in late August, my British publisher asked me to move quickly, for a change, and draw together the sections concerning Ebola virus from my 2012 book Spillover and, by editing and rearranging them into a stand-alone structure, to create a small book that could be published promptly. I’ve done that, adding a new Introduction, and a new Epilogue about the events of 2014. The result is Ebola: The Natural and Human History of a Deadly Virus, published by Random House in the United Kingdom in early October and by W.W. Norton in the United States on October 20. This is a book for people who are too busy, in an urgent and nervous time, or otherwise disinclined by lack of interest in the broader topic, to read Spillover. Its purpose is to give readers, including hurried news people and public officials as well as

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I flew into Bangalore, at the invitation of my old friend Ravi Chellam, to participate in the Student Conference on Conservation Science, held there during the first week of August.  It had been ten years or so--I don't recall exactly, but too long--since my last trip to India.  Great to see Ravi and his wife Bhooma, and to meet so many bright, intellectually hungry, poised and confident young conservation biologists. They were enough to give you hope for the future--which is something I don't say lightly.  During the four days of the conference I heard some very smart and useful talks, including one by Umesh Srinivasan, on understory bird populations in logged habitat, which eventually received a prize for best of the conference.  But I wasn't just there to listen; they put me to work, doing one plenary lecture (on zoonotic diseases, derived from my Spillover research) and two workshops (on science writing for the general public).  The event culminated, on Saturday evening, with a plenary talk by Bittu Sahgal, another old friend of both mine and Ravi's.  Bittu was empassioned and inspirational, as ever.  In closing, he told the next generation of conservation biologists: "I wish you curiosity.  And I wish you courage." 

Immediately following the SCCS meeting, also in Bangalore, was another: The bi-annual meeting of the Society for Conservation Biology,  Asia branch.  Again, hundreds of bright young (and some senior) biologists, not just from India but from all over the region, including Indonesia, Mauritius, and China. Those sessions, plus a good meeting with the tiger biologist Ullas Karanth, plus a quick trip over to Chennai, where I did two more lectures and toured the Madras Crocodile Bank, went far toward filling out this two-week India visit.  They worked me hard (I think it was four lectures, four workshops, and a panel in nine days) and treated me well (plenty of fine Indian food, and I scarcely was allowed to pull out my wallet).  I stayed in a guest-house apartment at the National Center for Biological Sciences, an impressive institution full of researchers and grad students, where my

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Greg Dwyer is a mathematical ecologist, Greg Dwyer is a mathematical ecologist.based at the University of Chicago, who studies outbreak populations of forest insects.  His work involves trying to understand the extreme boom-and-bust cycles of species such as the gypsy moth (Lymantria dispar), which explodes occasionally into huge infestations, defoliates trees throughout a region, and then suddenly crashes.  After a period of years at low population, another gypsy moth outbreak begins, the numbers increase suddenly and grotesquely, the infestation peaks for a year or two—and then comes another crash.  The main factor driving the crash phase of the cycle is viral infection, killing gypsy moths like a medieval plague.  That's why I recently went to see Dwyer at his office on the UC campus.  I thought his research and his ideas might help inform the final chapter of my book in progress, which concerns the ecology and evolution of scary viruses—the ones that kill humans, not gypsy moths.  The book will appear next year, under the title Spillover. 

Greg Dwyer is a mathematical ecologist.Dwyer is a rare combination: a highly sophisticated math guy who creates mathematical models of ecological processes, and a field man who still goes into the forest, collecting his own data.  He also runs a lab, in which he and his grad students and postdocs can watch the moth-virus interaction in its excruciating stages.  The virus in question is called nucleopolyhedrovirus (NPV).  There's a whole group of NPVs, some infecting such other forest insects as the Douglas-fir tussock moth and the Western tent caterpillar.   This one is specifically adapted to kill gypsy moths.  It consumes them from within, it dissolves them, it virtually melts them down—the way Ebola virus supposedly (but not in reality, only in the pop literature of Ebola hype) melts a human body.  For a gypsy moth, it's no hype.  "They pick up the virus," Dwyer told me, "they go splat on a leaf."

Then he showed me.  In the basement of the biology building, he unlocked a door to what he called "the dirty room" of his lab complex and invited me in.  From an incubator, one of his postdocs

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David Quammen and Christian Ziegler on the outskirts of Kinshasa.Lots of field time in the Congo for me this year.  The forests are wonderful; the people are likable; the cities, the logistics, and the politics are . . . ugh, challenging.  As you probably know, there are two countries known loosely as "the Congo":  the Republic of the Congo, north of the big river, with its capital at Brazzaville; and the Democratic Republic of the Congo (formerly Zaire), south of the river, with its capital at Kinshasa.  In past years, during the Megatransect and later outings, my Congo travel has always been north of the river.  This year I've spent seven weeks south of the river, getting a taste of DRC.  My main purpose has been to research a story on the bonobo, Pan paniscus, a species of primate sometimes (misleadingly) called the pygmy chimpanzee.  That's a work in progress for National Geographic. I've spent time in the forest with several bonobo researchers, including Gottfried Hohmann (who has studied them for decades) and Tetsuya Sakamaki, following wild but habituated groups.  In such situations, we've kept a respectable distance (ten yards, at least) from the animals and, when relatively close, worn surgical masks to lessen the chance of infecting them with some human bug.

If you've ever worn a surgical mask while trying to run through an equatorial rainforest, get air to your lungs, and keep your glasses from fogging up, you'll appreciate how much Gottfried and Tetsuya and their colleagues care about these creatures. 

I also spent a day at the Lola yaDavid Quammen and Christian Ziegler on the outskirts of Kinshasa. Bonobo refuge on the outskirts of Kinshasa.  It's an orphanage and halfway house for bonobos that have been captured, or grown up in captivity, and been rescued by an extraordinary woman named Claudine Andre, who runs the place.  Some of those animals are now being released to the wild—under carefully restricted conditions, into habitat empty of other bonobos.  The Lola bonobos are quite familiar with human contact.  My photographer colleague for this assignment, Christian Ziegler (that's him in the olive fatigues), had spent a week at the refuge before going to the wild and so,

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EBOLA: The Natural and Human History of a Deadly Virus



SPILLOVER: Animal Infections and the Next Human Pandemic



THE CHIMP AND THE RIVER: How AIDS Emerged from an African Forest