ALSO BY DAVID QUAMMEN NONFICTION The Reluctant Mr. Darwin Monster of God The Song of the Dodo ESSAYS Natural Acts The Boilerplate Rhino Wild Thoughts from Wild Places The Flight of the Iguana FICTION Blood Line The Soul of Viktor Tronko The Zolta Configuration To Walk the Line EDITED On the Origin of Species by Charles Darwin: The Illustrated Edition The Best American Science and Nature Writing 2000, with Burkhard Bilger
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SPILLOVER Animal Infections and the
Next Human Pandemic DAVID QUAMMEN
W. W. NORTON & COMPANY NEW YORK • LONDON
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again and ever,
to Betsy
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And I looked, and behold a pale horse: and his name that sat on him was Death, and Hell followed with him. And power was given unto them over the fourth part of the earth, to kill with sword, and with hunger, and with death, and with the beasts of the earth.
—REVELATION 6:8
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CONTENTS I. Pale Horse
II. Thirteen Gorillas III. Everything Comes from Somewhere
IV. Dinner at the Rat Farm V. The Deer, the Parrot, and the Kid Next Door
VI. Going Viral VII. Celestial Hosts
VIII. The Chimp and the River IX. It Depends
Notes Bibliography
Acknowledgments Index
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I PALE HORSE
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The virus now known as Hendra wasn’t the first of the scary new bugs. It wasn’t the worst. Compared to some others, it seems relatively minor. Its mortal impact, in numerical terms, was small at the start and has remained small; its geographical scope was narrowly local and later episodes haven’t carried it much more widely. It made its debut near Brisbane, Australia, in 1994. Initially there were two cases, only one of them fatal. No, wait, correction: There were two human cases, one human fatality. Other victims suffered and died too, more than a dozen—equine victims—and their story is part of this story. The subject of animal disease and the subject of human disease are, as we’ll see, strands of one braided cord.
The original emergence of Hendra virus didn’t seem very dire or newsworthy unless you happened to live in eastern Australia. It couldn’t match an earthquake, a war, a schoolboy gun massacre, a tsunami. But it was peculiar. It was spooky. Slightly better known now, at least among disease scientists and Australians, and therefore slightly less spooky, Hendra virus still seems peculiar. It’s a paradoxical thing: marginal, sporadic, but in some larger sense representative. For exactly that reason, it marks a good point from which to begin toward understanding the emergence of certain virulent new realities on this planet—realities that include the death of more than 30 million people since 1981. Those realities involve a phenomenon called zoonosis.
A zoonosis is an animal infection transmissible to humans. There are more such diseases than you might expect. AIDS is one. Influenza is a whole category of others. Pondering them as a group tends to reaffirm the old Darwinian truth (the darkest of his truths, well known and persistently forgotten) that humanity is a kind of animal, inextricably connected with other animals: in origin and in descent, in sickness and in health. Pondering them individually—for starters, this relatively obscure case from Australia—provides a salubrious reminder that everything, including pestilence, comes from somewhere.