We've been AWOL from the cocktail party the last week, partly because I was giving a talk and public lecture at Union College (where I got to meet the very tall -- like, 6 foot 6 -- and very personable Chad Orzel of Uncertain Principles), but also because I came down with some nasty virus that, while not rendering me completely useless, has greatly sapped my energy. Also my voice -- those attending the Union College lecture can attest that I could barely croak out concurrent syllables by the end of the Q&A. Plus, I had to fly back to Los Angeles with all that congestion, resulting in an uncomfortable ear blockage. Woe is me.
If anyone on my flight happens to come down with a sore throat, headache, and sinus congestion in the next week, mea culpa. But at least it wasn't extensively drug resistant tuberculosis, like that idiot who ignored his doctor's warnings and exposed two jets full of transcontinental passengers to his illness. Tara and Mike over at Scienceblogs have more detailed accounts. Suffice to say, public understanding of science has hit an all-time low when a self-proclaimed "well-educated" man can't seem to grasp that his insistence on traveling with active TB endangered the health of hundreds of others. Or maybe he just doesn't care, which is an even more frightening prospect.
Seriously, in this era of pandemic panic and avian flu, of AIDS, and mad cow disease, when people freak out over the slightest hint of contamination, have we forgotten about older, equally deadly diseases like tuberculosis? Or cholera? It's not like they've been stamped out completely. Cholera in particular is still killing people in disadvantaged countries, most notably the poorer regions of Africa. My pal Kimba just took a job with Doctors Without Borders and leaves soon for a posting in the Congo. Part of his training at Hopkins in epidemiology focused on water supplies, proper sewage/drainage, and sterilization of drinking water -- because polluted water is a breeding ground for cholera.
In the 19th century, England's physicians, scientists and political leaders watched with trepidation as cholera morbus moved from India through Eastern Europe, to Germany and the very shores of England, officially "arriving" in London in 1831, killing well over 10,000 people in one year alone. In 1854, London's Soho District was hit by an especially virulent outbreak of the disease, appearing quite suddenly, and killing 127 people in the first three days. By the time it was over, 616 people had died.
Cholera is a particularly nasty way to die. it starts with horrible bouts of vomiting and diarrhoea and a slowed pulse, plus cramps. Those craps became severe as the disease progressed, with the victim's entire body convulsing in pain. Eventually the lips, face, hands, feet, and soon the entire body turn blue, purple or even blackish in hue. The skin becomes cold and amp. Respiration slows gradually, but instead of a telltale death rattle in the throat, victims often die quietly, with a whimper. At least the disease progression is rapid, so one's misery is intense, yet short. That's about all that can be said for it.
But how did the disease spread? Medical opinion was divided, because the evidence was contradictory, sometimes indicating transmission through contact, sometimes indicating transmission through squalid unsanitary conditions. The latter certainly prevailed in the Soho of the 1850s, filled with animal droppings, runoff from slaughterhouses, primitive sewers, and had anyone checked under the floorboards of their cellars, they would have found foetid cesspits.
The man who solved the mystery of the 1854 outbreak was Dr. John Snow, today recognized as a pioneer of modern epidemiology. He lived on 5th Street, making him a local, and thus was able to monitor the epidemic's progress pretty much on-site. He was already convinced that cholera was spread by a poison passed from victim to victim through sewage-tainted water; in fact, he'd already traced an earlier outbreak of contaminated water supplied by the Vauxhall Water Company. The problem was, authorities didn't believe him, and the water company refused to admit any culpability. He figured this was his chance to prove his theory was right.
So he patrolled the district, interviewing the families of those who had died, and found that nearly all the deaths had occurred near a water pump on the corner of Broad Street and Cambridge Street -- the epicenter of the oubreak. Houses closer to an alternate pump had only experienced 10 deaths, and five of those were schoolchildren who occasionally drank from the Broad Street pump. Ever the scientist, Snow took a sample of the pump's water, examined it under a microscope, and noted that it contained "white flocculent particles," which he deemed the cause of the infection.
While still skeptical, the Board of Guardians in St James Parish reluctantly followed his advice and removed the pump handle as an experiment. The spread of the disease stopped dramatically (although some still argued that the outbreak was already on the decline). There were still a few unexplained deaths from cholera that appeared unrelated to the Broad Street pump. The most damning was a widow who lived in Hampstead, and her niece, neither of whom lived anywhere near Broad Street. Snow proved quite the detective: he found that the widow had once lived in Broad Street and liked the taste of that well water sufficiently that she had a servant bring her back a large bottle from it every day. The last bottle had been fetched on the day the Soho outbreak began.
It's hard to believe that authorities were still doubtful of Snow's findings. My favorite anecdote on Snow was gleaned from a new book I've been reading during my convalescence by Sandra Hempel called The Strange Case of the Broad Street Pump (highly recommended). A local vicar, Reverend Henry Whitehead, thought the outbreak was the result of divine intervention -- a very Pat Robertson-like approach to human calamity -- and set about "proving" his case. Unlike today's more pig-headed religious figures, Whitehead actually confirmed Snow's theory. In fact, he helped confirm a single probable cause of the outbreak: a young child living on Broad Street had been ill with cholera symptoms, and its diapers had been soaked in a tub of water that was subsequently emptied into a cesspool a mere three feet from the Broad Street pump. Underground leakage did the rest. (That household had the excuse of understandable ignorance, which the TB-infected man did not.)
Fourteen years after Snow's targeting of the Broad Street pump, a cholera epidemic hit Buenos Aires, Argentina. I found an account of the outbreak online, via an excerpt from Charles Darbyshire's My Life in the Argentine Republic 1852-1894. He had moved his household to the countryside, in large part because he worried about the unsanitary conditions of town life, having seen the impact of cholera in London before he came to Argentina. He described the conditions in alarming detail:
"I felt positive that sooner or later there must be an epidemic. There was no drainage. The soil on which the houses were built was becoming infected. The defecations, the waste water from kitchens, etc. went into wells 30 feet deep in the back patios. When one of these wells became full of filth and could hold no more, what was called a sangria (a bleeding) was made. A well was sunk to the same depth... and the sangria took place by pushing an iron bar through the fell well... as the old well began to drain into the new. This went on for years, and some of the patios in the old houses were honeycombed by wells."
Darbyshire's fears proved well-founded when an epidemic broke out in the summer of 1868, brought about (he believed) by Brazilian ships tossing the bodies of those who had died from cholera into the River Parana, thereby contaminating the water supply. People in the cities fled to the countryside, bringing the disease with them, and Darbyshire soon found himself in the position of a public health leader, advising his neighbors on removing themselves from unsanitary conditions, not drinking water unless it was boiled, burying all refuse, keeping floors and patios clean. The 12 people in his own household did not contract the disease, which probably lent credence to his his advice. Despite all the deaths, there was one positive outcome: the Argentine government overhauled the city's drainage system and installed a proper water supply.
By 1991, cholera was back in Buenos Aires, causing a bit of an international dispute between Argentina and Peru in the bargain. Argentina blamed the outbreak on an airplane flight from Peru to Buenos Aires carrying infected passengers, which Peru's president claimed were attempts to "smear the image of my country." Argentina had a strong case: cholera did break out in Peru in 1991 and thereafter spread throughout several other Latin American countries, infecting 367,000 and killing 3,900. (At least we've gotten better at keeping the death tolls from cholera down. A little.)
Some good came out of that calamity as well. A 27-year-old Stanford postdoc named Rebecca Hwang grew up in Buenos Aires. (She was born in Korea.) She lived through the cholera outbreak in Argentina, clearly remembering having to dribble cholera-killing bleach into vats of boiled water -- the family's daily supply. They did this for two years. She later realized that developed nations had advanced resources that enabled them to avoid being affected by the 1991 epidemic.
Hwang now studies water treatment ecosystems in rural India and Nicaragua, and designs advanced filtration devices and other methods for improving water treatment in less developed regions. (Jen-Luc's favorite quote from Hwang: "You see the most disgusting water sources, with contamination so visible that [many people] would throw up before drinking from there -- and then you see women collecting the water to cook with.") But she recognizes that the biggest obstacle isn't technology. The technology exists. The trick lies in overcoming financial and institutional roadblocks. The vital infrastructure that we take for granted in this country is often lacking, or just simply too inefficient to be effective.
She's as diligent as Dr. John Snow when it comes to realizing her objectives. Lately she's turned to computer modeling of social networking systems, an intricate array of nodes connected to each other in a variety of different ways. In many ways, it's an ideal model/analogy. Up to 70% of Argentina's water is suppled by small community cooperatives loosely stitched together like a patchwork quilt. Those coops in turn are badly managed and slowed down by internal bureaucratic red tape. Hwang is trying to find ways to make the coops operate more effectively using social networking theory, mapping the relationships between decision-makers at the coops to identify patterns of strengths and weaknesses, which can them (one hopes) be improved upon. The money quote: "These calculations give you a sense of who the central nodes of the network are... [for example] who is popular... you are able to know some very important characteristics of the structure or architecture of the network."
Social networking is related to the small world phenomenon, better known to most of us as "six degrees of separation," and epitomized by the popular game "Six Degrees of Kevin Bacon," in which players tried to make random connections to the actor based on those who have been associated in some way with his movies. The original 1967 study by Stanley Millgram has fallen into some disrepute, when it was revealed that his famous experiment and conclusions were based on a minuscule data sample. Out of 60 letters, 50 people responded to his challenge to forward the letter via their social network, and only three letters eventually reached their destination. But it does seem to be true that smaller communities, such as actors and mathematicians -- "What's your Erdos number?" replaces "What's your sign?" as the pick up line of choice in math and science departments -- are densely connected by chains of personal or professional associations.
We wish Hwang the best in her mission to improve the water treatment infrastructure of developing countries. And should she be on the lookout for a nice Korean man who shares her interest in sewage and epidemiology, Kimba is still single, ladies.