John Snow Knew Something
The beginning of epidemiology and Germ theory.
In 1854 an area of London around Broad Street had a serious problem, which in turn was part of a long string of cholera outbreaks that affected 19th century London. Starting on the 31st of August and continuing for the next 3 days, 127 people near Broad Street diet. At the peak of the outbreak, only 10 days later, 500 people died.
A 41-year-old physician tasked himself with identifying and stopping the epidemic before it got worse. A physician named John Snow.
Dr. Snow was an oddity for his time. For starters, he didn’t believe in the pre-emptive theory of disease known as Miasma. This idea was thousands of years old by the time of Dr. Snow’s life. It stated that decomposing matter or other dirty organic sources lead to particles in the air that travel around and infect people.
What Dr. Snow believed, and what he wrote about, was known as the Germ theory. This idea was that small living organisms traveled from one person to another person. In the case of cholera, Dr. Snow believed that this germ cell actually came from the excrements of other humans contaminating a water supply.
Bacteria had been known to science since the 1670s when the first descriptions of bacteria were made by Anton van Leeuwenhoek. But the connection from these ‘animalcules’ to something that was making everyone sick was new. Only around 1810 had Agostino Bassi of Italy demonstrated a “vegetable parasite” caused an illness in silkworms that devastated the French silk industry. This parasite is now known to be a fungal infection that careers Bassi’s name Beauveria bassiana.
John Snow was diligent in his investigations. Believing that Cholera had to come from some source, and not just floating in the air, he searched for that source. He questions many of the victims and residents until he tracked down the water source to a public water pump. With his data in hand, he managed to persuade the St. James parish authorities to disable the pump.
The outbreak quickly resolved, however in John Snow’s own words, it may have been declining otherwise
There is no doubt that the mortality was much diminished, as I said before, by the flight of the population, which commenced soon after the outbreak; but the attacks had so far diminished before the use of the water was stopped, that it is impossible to decide whether the well still contained the cholera poison in an active state, or whether, from some cause, the water had become free from it.
Dr. John Snow proved that cholera was coming from this pump and that it was passing from an oral-fecal route. He believed that the Germ theory was true, and if it was true, he could find the source of the infections and put a stop to them.
While his work was unappreciated, in fact just after the outbreak the parish replaced the handle to the water pump, they could not accept the oral-fecal transmission route that Dr. Snow proposed as the cause, he would later be proved correct and would be known as the father of Epidemiology.
It would take another 30 years, with the work of Louis Pasteur and Robert Koch before the world would replace the ideas of Miasma with the Germ theory and modern ideas of where infections come from and how to treat them.
This is the beginning of a series of articles about infections. I felt a grounding in history would give everyone a nice footing. My apologies for the Wikipedia links, but the original articles are from the 1800s and Wiki has the best synopsis. The next article is about bacteria and antibiotics.
