John Snow and the defeat of cholera.
A great plague, like one of those with which Egypt was stricken in Pharaonic times, swept across the eastern world in 1817. It originated, although no one at the time knew it, in the Sunderbund swamps of the Ganges Delta, where the sub-visible causal agent, the bacterium, Vibrio cholerae, had been quietly mutating for millennia. Sinisterly, this organism was a threat to only one species: it was a killer solely of that latecomer to the planet, Homo sapiens. Successive pandemics devastated India, desolated Persia, ravaged Syria, and, by 1831, the black cloud loomed ready to wreak its lethal havoc in Europe. But there, man was to do battle with, and eventually conquer, the invisible assassin.
The pioneer researcher, his name unjustly barely remembered today, was John Snow, and this book celebrates and commemorates his achievement in laying the foundation of medicine's modern victory. The first choleraic pandemic began in 1816, and, attaining epic proportions in Bengal, had spread throughout the subcontinent by 1820. Then, after travelling in company with pilgrims, soldiers, and caravans along the trade routes--through south east Asia to the Phillipines and China, on towards the Russian borders, east into Japan, via the Persian Gulf into and cross Persia to the Ottoman Empire to threaten Europe and, finally, reaching Astrakhan, by the Caspian Sea, suddenly and unexpectedly to subside.
The second pandemic began in 1829, and lasted until 1852. The cholera arrived in London in 1832. Seven thousand victims died, and the clinical picture came into terrifying focus. The first symptoms were nausea and dizziness, succeeded by violent vomiting and diarrhoea, with stools turning to a grey liquid, often described as 'rice-water'. Extreme muscular cramp supervened, accompanied by an insatiable thirst, the pulse rate dropped, a terrible lethargy set in, and, dehydrated and near death, the sufferer displayed the classic cholera physiognomy: puckered blue lips and a cadaverous face.
The doctors were totally unable to account for the origin of the pestilence. They had no idea how it was communicated. Some held the miasmatic view, believing that the disease emanated from the earth; others concluded that it resulted from epidemic constitution--a phrase of Thomas Sydenham's coinage descriptive of changing environmental conditions, such as climate changes, or sudden variant influxes of novel influences. But John Snow thought differently. Born in York in 1813, a farmer's son, he had, at the age of fourteen, been apprenticed to a Newcastle surgeon, William Hardcastle, progressed to the Hunterian Medical School, in London, where he settled and eventually became a respected medical practitioner. It was his conviction that because the infection attacked the intestines and not the blood system, or the lungs, it was not consequent upon a poison in the ambient air, not breathed in, but was water-borne; swallowed in polluted water. His suspicions focalised upon the drinking water. The resolution became effectively a contest between epidemiological and microbiological investigation. Snow traced the source of the current Soho outbreak to a pump in Broad Street, and postulated the oral-faecal route of acquisition, per aqua. His professional brethren thought him 'very unsound': a case of epidemiological deduction without microbiological demonstration. It was not until more than twenty years later, in the course of the third pandemic, that another medic, Arthur Hill Hassall, became, without realising it, the first man to see the cholera bacillus. But he made the mistake of regarding the minute, comma-shaped bodies, whose presence his microscope revealed in samples of London water, as the result of the disease rather than as its cause. It was the German 'Father of Bacteriology', Dr Robert Koch, who first correctly identified the mass-killer microbe. Snow died, unmarried, in 1858. He was only forty-five.
In 1993 a new strain, the 139th to be discovered--and therefore known as Strain 0139--erupted in India and Bangladesh, and rapidly spread to south east Asia. The current demand for migrant work forces, the lifting of border restrictions, the flood of persecution fleeing refugees and the shrinkage of the world as a result of wide-ranging air travel, all these contribute to optimum conditions for a choleraical resurgence. No case can be made for a relaxation of vigilance.
Susan Hempel has reduced a complex story to an account of admirable lucidity, and has contrived to negotiate the pricklier scientific thickets with maintained readability.
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|Title Annotation:||The Medical Detective: John Snow and the Mystery of Cholera|
|Article Type:||Book review|
|Date:||Dec 22, 2006|
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