Cholera
is one of those diseases that the major industrialized Western countries no
longer remember: it is a malady of the
third world or a long-forgotten past.
The
United States still has a few dozen reported cases every year, but no one has
died from it in years. We no longer
remember the years in which over a hundred thousand succumbed annually, or that
it was the disease that killed former President Polk. Outbreaks in third world countries rarely
make the news, since this is a problem no longer relevant to us.
Cholera
is an infection of the intestines by the bacterium Vibrio cholerae. While the incubation period can be anywhere
from just a few hours to several days after exposure, and the symptoms may vary
greatly, in the most severe cases the victims die of dehydration after
experiencing days of vomiting and copious watery diarrhea.
The
disease is actually a hazard of urbanization and overcrowding. Its spread is a result of the rapid rise of
urban populations and the associated concentration of human waste. And, of course, the eradication of cholera in
the cities turned out to be a by-product of the solution to the urban human
waste problem. Having solved that waste
problem, of course, we have forgotten exactly what happened.
In
the middle of the nineteenth century, London was already a city of over two
million people, who were crammed into a impossibly small amount of real estate—the
most populous city on earth. And it stunk...Literally
stunk. With no centralized sewage system,
every building in the town had its own cesspool, all of which overflowed with
human waste and were sporadically emptied—by buckets—into waste carts that
simply dumped their contents into the Thames River. The Thames, of course, was also the
source of drinking water for London—so convenient!.
None
of this particularly worried the health officials, who knew that disease was
spread by "bad air"—the miasma theory. Every educated person for millennia had known
that harmful vapors that were the result
of rotting organic matter spread diseases like the plague, cholera, and
chlamydia. (By the days of Victorian
England, some physicians were blaming obesity on the effect of inhaling the
odor of food!)
In
1849, there was yet another outbreak of cholera in London, which began with the
death of only twelve people. A
physician, John Snow, noticed something interesting about the outbreak. The first case was a seaman who had just come
from Asia. A week later, the second case
was a man who lived in the same room at the same boarding house cottage. In total, all the victims lived in a row of
cottages that shared a single well. Snow
reasoned it was highly unlikely that the "bad air" had hung around in
the same room and the same buildings for a week.
On
examination, he discovered that a drainage channel for waste water ran in front
of the house. Despite the fact that the
rock-lined channel had visible cracks that allowed the waste water to seep into
the well, the cottage tenants continued to use the channel for an open
cesspool. While Snow had absolutely no
idea how the disease spread (this was more than a decade before Pasteur would
postulate his germ theory) Snow reasoned that the disease was spread by the
contaminated water.
He
published a paper on the subject—a paper that was almost completely
ignored. The city's health officials
absolutely believed in the miasma theory of disease. ('Hell, you could smell the filth in the
air...') Not surprisingly, the cholera
outbreak spread, eventually killing 14,137 people in 1849.
In
1854, London suffered another outbreak in Soho.
While today this is a delightful area of town, noted for its galleries,
trendy nightclubs, pubs, and small expensive boutiques, in 1854, it was a slum
so packed with people that each room in the buildings housed an average of four
people. Centuries-old overflowing
cesspools lay just a few feet away from public water pumps.
The
first case of cholera in this outbreak was a six month-old infant. In the next three days, another 127 people
died. This triggered a panic and
residents of London began fleeing the city in numbers not seen since the Great
Plague of 1666. Within a week,
three-quarters of Soho had fled. The
Soho outbreak was far worse than average:
the area around Broad Street was quite literally decimated—one-tenth
of the population died.
Snow
lived in Soho, and he began interviewing the victims' families. He also began marking a map with the location
of the victims' homes and it did not take long for a distinctive pattern to
emerge. Almost all of the victims lived
near a specific public water pump on Broad Street. The infant who had succumbed first lived in a
house with an overflowing cesspool located
just three feet from the well.
Unexpectedly,
several of the victims lived closer to public pumps other than the one on Broad
Street and there were no cholera cases among the workers at a large brewery
adjacent to the pump.
Snow
continued his interviews and discovered that the workers at the brewery were
offered free ale while they worked, so they did not drink the water. (Water from the well was used to make the
ale, but the fermentation process killed the cholera germs.) And the water from the contaminated Broad
Street pump was popular with many Soho residents who, despite living closer to
other public pumps, walked the extra distance because the "water tasted
better".
Snow
took his evidence to the public health officials who all but laughed at his
novel ideas. Still—if only to help
pacify the hysteria—they ordered the removal of the pump's handle, effectively
shutting down the well.
The
popular story is that this immediately stopped the epidemic and public
officials immediately recognized that Snow was correct. Neither of these stories is actually correct. By the time the well handle was removed, the
epidemic was all but over, the contamination within the well was probably
flushed out by this time.
Nor
did the public officials change their minds about miasma. Following the epidemic, public officials scoured
Soho looking for the reason the outbreak had been so violent. They focused their attentions on ventilation
of homes, adequate windows, and looking for peculiar smells and odors. It was only decades later than Snow's
work began to be appreciated. Today it is recognized as the beginning of the study of epidemiology.
Even
less well remembered is that while Snow's insistence on having the pump handle
removed did not really stop the cholera outbreak, it probably did stop the
"next outbreak". The
very day the pump handle was removed, the infant's father came down with cholera. And that cesspool was still leaking
into the well.