Friday, October 19, 2012

A Sneeze Heard Around The World

It's probably not the best idea to read, as I did, David Quammen's Spillover while suffering from a cold caught on a transatlantic flight.  Spillover is a pacy, punchy book about zoonoses, the diseases we catch from animals; several - SARS, for instance, or the H5N1 virus which caused bird flu - are respiratory diseases whose spread was amplified by air travel.  As human beings disrupt natural ecosystems, we encounter new infections, and quickly disperse them across the world.  Spillover's accounts of Ebola, HIV, SARS, H5N1and other actual or potential pandemics are gripping scientific detective stories about isolating and identifying disease organisms, tracking paths of infection back to the first victims, discovering how they became infected, and identifying the animal species - often bats or monkeys - in which the disease originated.

Quammen, who works for the National Geographic, has done an immense amount of fieldwork, observing researchers catch fruit bats in Pakistan, trekking through forests in the Congo in search of gorillas and chimpanzees infected with ebola, spelunking in a bat- and python-infested cave where tourists contracted Marburg disease, visiting the laboratory in which old tissue specimens were found to contain the first known example of the HIV virus.  There's a long, entirely ficticious account of how HIV may have spread in the colonial Congo, but for the most part Quammen scrupulously sticks to the science, and his lucid accounts of human loss and the scramble to contain outbreaks of horrific and deadly diseases hardly need embellishment.  It's terrific, sobering stuff, the raw material of a dozen possible apocalypses.

As far as viruses and other disease organisms are concerned, the seven billion human beings presently alive are a vast warm, wet reservoir of mucous membranes and the cytoplasmic machinery they need to reproduce.  We live in densely populated cities that enhance the spread of infection between individuals, and transport infections across the entire globe.  We have not separated ourselves from the natural world; we are one of its ecosystems.  Indeed, as Quammen observes, 'there is no 'natural world', it's a bad and artificial phrase.  There is only the world.  Humankind is part of that world, as are the ebolaviruses, as are the influenzas and the HIVs, as are the Nipah and Hendra and SARS, as are chimpanzees and bats and palm civets and bar-headed geese, as is the next murderous virus - the one we haven't yet detected.'

We can't escape diseases because they and we are inextricably embedded in the global environment. Our only advantage is that we are smart - smart enough to be able to detect and identify new diseases, and contain them before they can spread.  It's a constant battle - a new virulent coronavirus (SARS is another) has recently caused a handful of deaths, and has the potential to spread more widely.  So far we're winning the race.  We've equipped ourselves with a global network of dedicated lab scientists and field workers armed with techniques than can rapidly isolate disease organisms, sequence their DNA and RNA, and identify their weak spots.  But we can't ever stop running.  Our civilisation is now obligately dependent on molecular biology.

There Are Doors (18)

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