With COVID-19, his value has become more understood: Who is John Snow?

John Snow, known for his treatment of people in the Soho district of London, his contributions to epidemiology, and his work on hygiene and anesthesia, was born on March 15, 1863, in York, as the child of a poor family. His father is a mine worker and his mother is a housewife. Despite their difficult situation, his mother sent him to a nearby private school. During his surgical training in New Castle when he was only 14 years old, he became one of William Hardcastle's most popular students.

When Snow was 17, a cholera epidemic broke out in the city of Newcastle. As a student, he cared for patients suffering from cholera. While dealing with cholera, he realized that the disease was transmitted through swallowing, not through the air as was thought. Thus, Snow explicitly rejected the so-called Miasm Theory. The Miasma Theory is an invalid hypothesis that has been completely disproved today, claiming that diseases are transmitted through "bad air" rather than microbes.

John Snow (15 March 1813 – 16 June 1858) was an English physician and a leader in the development of anaesthesia and medical hygiene. He is considered one of the founders of modern epidemiology, in part because of his work in tracing the source of a cholera outbreak in Soho, London, in 1854, which he curtailed by removing the handle of a water pump.[citation needed] Snow's findings inspired the adoption of anaesthesia as well as fundamental changes in the water and waste systems of London, which led to similar changes in other cities, and a significant improvement in general public health around the world.

John Snow's thoughts about the transmission of diseases became more concrete in London, where he later went to get the title of "doctor". After working in a hospital in London for a while, he was able to enter the Royal College of Surgeons. After his education here, he left the Pharmacists Society with the title of "pharmacist" and opened a pharmacy in the Soho neighborhood, where he would work in the future. Not only that, he graduated from the University of London as a medical doctor and from the Royal Academy of Medicine as a member of the Elite Doctor class.

Solving the Mystery of Cholera...

According to Snow, cholera is transmitted through water, not air. As a justification, he claimed that, contrary to popular belief, slaughterhouses do not pollute the air or spread cholera, and if that were the case, the first people affected would be slaughterhouse workers. He was able to prove in autopsy studies that it was transmitted by swallowing, with damage to the intestines instead of the lungs. He suggested that water here contributed significantly to the spread of cholera.

A cholera epidemic broke out in London at a time when cholera epidemics were endless and deeply affected the Soho region. Snow mapped the epidemic areas as in his first study, so he could reach how many cases were where. According to Snow's results, the closer you got to a water pump on Broad Street, the more frequent cholera cases were.

Thanks to the data he collected, he managed to determine that a single fountain in the region was the main source of cholera. Thereupon, Snow persuaded the local government to remove the fountain pump, and with this simple move, he managed to significantly reduce the cholera epidemic in the region in 1854.

John Snow published these studies in the British Medical Journal in 1857. The data presented in this publication showed that cholera is much less common in households located closer to the source in water distribution networks, and that cholera is much more common in households located further away, where water comes through intermediate stops. Therefore, cholera must be a disease directly related to water resources, not for some vague reason such as "bad air".

In another study he conducted to support his ideas, he mapped the death rates of 32 neighborhoods in London. It was concluded that the presence of human feces in drinking water was the factor that accelerated the spread of cholera the most. However, his work was not popular among proponents of the Miasma Theory, which argued that diseases were transmitted through "bad air". Moreover, since water was pumped into wells at that time from contaminated sources such as the Thames River, the water companies and government of the time did not want to take on the financial burden of changing or filtering these water sources. Miasma Theory, although not invalid, was seen and defended as a more profitable theory.

Although he was not very popular during his time, he became famous years after his death because his name was mentioned in research on epidemics and cholera. In addition to the research, the biography written by his friend Benjamin Ward Richardson, a physician and biographer, is an important source for historians about Snow.

Whether famous or not, Snow's contributions to the world of science are great. Snow's research area is not limited to epidemiology and anesthesia; being a surgeon, he has made significant contributions to the development of hygiene.