If you remember one thing from this short review: stay away from bats and try not to eat exotic animals (e.g., apes, monkeys, civets) if you can help it. Both are excellent ways to become the next Patient Zero for a brand-new zoonosis.
You could be forgiven for not knowing the word “zoonosis,” but, without question, you know zoonoses: HIV. Influenza. Ebola (recently back in the news*). Rabies, and dozens of lesser-known diseases – they’re all zoonoses: animal infections transmissible to humans.
And when The Next Big One – a global pandemic that causes untold suffering and remarkable morbidity and mortality – descends upon the earth as one of the Four Horsemen of the Apocalypse, it’ll almost certainly be a zoonosis. This has happened in the past: a simple flu in 1918 killed something like 50 million people. This is happening in the present: HIV’s toll is 25 million and counting. And it will happen again, probably sometime soon; The Next Big One will spill over from an animal population into a human population, and it’ll wreak havoc.
Spillover – as in a moment, an event, a noun – is an evocative word. It brings to mind something vaguely chaotic, worrying, and uni-directional; once it has occurred it can’t un-occur. Spillover is, in other words, an excellent title for David Quammen’s fantastic book on zoonotic diseases.
Quammen is an engaging, lucid, and often very funny writer. He is transparently curious and intelligent-without-trying-to-seem-intelligent, and he has a potent ability to distill complicated scientific jargon to something more palatable for the lay reader.
Spillover is the end result of years of reporting that took Quammen around the world, from the humid jungles of Malaysia to the humid jungles of the Democratic Republic of the Congo to the humidity-controlled laboratories of America’s most precautionary disease research institutes.
What he finds is both deeply distressing and mildly encouraging. The bad news: The Next Big One is coming. Full stop. The good: when it does, the world is more prepared than any other time in history to address it.
And it should be; as Quammen outlines, we’ve had a number of (relatively) dry runs to learn and improve. Take SARS, the early 21st century disease that traveled from China to the rest of the world on airplanes. A muffled reaction by the Chinese government no doubt led to excess deaths (there were 774 in total around the world, from about 8,000 cases), but the disease was contained and eventually squelched out – for now. As Quammen puts it, SARS was bad but ultimately “an outbreak, not a global pandemic.”
Why? What made SARS The Next One but not The Next Big One? For starters, the outbreak started in China and spread to Singapore, Vietnam, and Canada – not Bangladesh, the Democratic Republic of the Congo, or other infrastructure-poor countries. Quammen writes,
“If the virus had arrived in a different sort of big city—more loosely governed, full of poor people, lacking first-rate medical institutions—it might have escaped containment and burned through a much larger segment of humanity”
As bad as the virus was (is), symptomatically it could have been much, much worse. The mortality rate was about 10% (though in other environs this could have been much higher), and, crucially, with SARS,
“symptoms tend to appear in a person before, rather than after, that person becomes highly infectious. The headache, the fever, and the chills—maybe even the cough—precede the major discharge of virus toward other people.”
A 90% chance that you’ll live isn’t encouraging, but at least with SARS your family and your neighbors know you’re sick before you can infect them.
Imagine a nasty strain of influenza that was as infectious and as lethal as SARS, but that breaks out in Nairobi or Lagos – a dense city with health infrastructure not up to the task of a mass outbreak that also has all kinds of international flights – and has time to infect before it presents symptomatically. That is the Next Big One.
But step back from any individual spillover and ask a larger question: why do spillovers happen at all? Because they’re inevitable, provided humans interact with animals; viruses (especially RNA viruses) mutate – evolve – constantly, and every once in a while they do so in a way that allows a human to become infected.
We’re making it worse, though. Increases in human population and the resultant erosion of natural “walls” between man and beast (so to speak) are putting humans in ever closer contact with animals, and globalization is inexorably accelerating the ability of one human to affect another. This is one of Quammen’s main points: diseases, and outbreaks, have an ecology to them, and in our razing of the rainforests and regular forests we’re building the perfect environment for spillover events.
Read the book.
*If you’re reading this in 2014, the ebola outbreak in West Africa is probably on your mind. Unless you live in West Africa – or, for that matter, East Africa – you simply don’t have anything to worry about. Ebola isn’t contagious in the same way that, say, influenza is contagious – by droplets in the air – and it’s too deadly and quick-to-incubate to cause sustained horror. It burns itself out. What’s happening in West Africa is horrible, but it isn’t The Next Big One.