PANDEMIC
Tracking Contagions, From Cholera to Ebola and Beyond
Sonia Shah
Sarah Crichton Books
271 pages; $26
Sometimes, the best approach to a book about deadly pathogens is to read it in a slightly dissociated state - it allows you to marvel at the cunning adaptability of microbial life, rather than contemplate the far creepier possibility of your own doom. In her introduction to her book, Sonia Shah, a science writer whose previous books include The Fever and The Body Hunters, does not seek shelter in euphemisms or shy away from scary numbers. Instead, she cites a study in which 90 per cent of epidemiologists say they believe a global pandemic will sicken one billion and kill up to 165 million within the next two generations.
Looking closely at the source of this statistic - a paper by the epidemiologist Larry Brilliant and three colleagues - I'm not convinced that things are quite so dire. But there's no doubt that new forms of pestilence are appearing in the world with an almost metronomic regularity and that old ones are reappearing in new places, the Zika virus being only the most recent example.
Yet once you get past the introduction, and once you get past the chilling biology lesson of Chapter 1 - which explains how these sneaky organisms jump from one species to the next - Pandemic is far less terrifying, perhaps because errant microbes are only one component of what makes a pandemic a pandemic. They're the "known unknowns," as Donald R Rumsfeld might put it. The other components are known knowns, which by definition are at least familiar: filth, political corruption, increasing population density and mobility.
Ms Shah uses cholera as a paradigm to explain how new deadly pathogens emerge and circulate. A discussion about the East India Company's expansion into the wetlands in the Bay of Bengal, which exposed many Indian workers to the tiny crustaceans that carry vibrio cholera, becomes the perfect segue to discuss how modern deforestation in Guinea encouraged more interaction between people and fruit bats, which are thought to carry Ebola.
"As wetlands were paved over and forests were felled, different species came into novel, prolonged contact with each other," she explains.
For those who don't know much about the history of cholera, Ms Shah's dense, compact book is a decent primer, explaining how new forms of transportation encouraged the spread of this waterborne disease, as did rising urban density.
Perhaps my favourite chapter, though, is about waste - or, as Ms Shah puts it, "the rising tide of feculence." Nothing seems to awaken the muse in Ms Shah like excreta, the ideal delivery system for all kinds of diseases. In each gram is up to one billion viral particles; yet somehow, Christianity shunned water-based rituals for centuries. Martin Luther went so far as to eat a spoonful of his own faeces every day.
In the age of cholera, shipping trade helped spread disease. Today, it's air travel - if you want to understand the helter-skelter distribution of flu outbreaks, simply consult a map of airline routes. In the age of cholera, politicians obfuscated and denied their way through the epidemic; today, the World Health Organisation, the globe's dedicated first responder, is so deprived of public funding that its private donors disproportionately control the agenda - which often has nothing to do with controlling pandemics.
Today overcrowding is not just in cities, but on farms, which have gotten denser and dirtier. In the United States, they've become breeding grounds for E coli; in China, poultry farms have grown so large they've created many opportunities for interactions with wild waterfowl, which can lead to new strains of the flu.
Complicating matters is climate change. Warmer waters have washed cholera-rich surf into Alaska and Chile and Iceland. A cold winter altered the migration patterns of wild swans in 2006, which meant they ferried a new flu into more than 20 countries in Europe; an unseasonably warm New York winter in 1999 contributed to the West Nile outbreak.
To me, however, the most provocative part of the book is not about the ways humans have altered the evolution of pandemics. It's about the ways pandemics have altered the evolution of humans. Pathogens, Ms Shah explains, have always been the body's antagonists. Every time we adapt to combat one, it counter-adapts to harm us back.
It is for this reason, she writes, that some evolutionary biologists believe we've evolved to have sex, rather than to clone ourselves - by diversifying the gene pool, we're confounding pathogens, making it harder for them to keep up with our ever-shuffling genetic variations.
Ms Shah ends her book on both a hopeful and cautious note. She makes a case for building a worldwide, highly attuned surveillance system. "A network of clinics," she writes, "staffed with health care workers trained to recognise and report new pathogens, could do the trick."
No doubt it would. But, politically speaking, achieving this goal is about as likely as eradicating pathogens themselves. Now that is scary.
©2016 The New York Times News Service
