Cholera map and a John Snow

The middle of the nineteenth century. The western part of Europe is beginning to change in the wake of the Industrial Revolution, and London, the capital of Britain, is no exception. New factories are being set up in every corner of the city, and people from other areas are flocking to the city in the hope of finding work. The size of the city is constantly increasing to cope with the pressure of this growing population. But even then, it is not possible to make room. In Greater London, 300 to 400 people per acre have taken refuge, while in skyscrapers like Manhattan, now there are no more than 100 people per acre.

In addition to this dense population, the lack of sewerage and waste management poses a greater threat to public health. So it didn’t take long for the idea that the air in London, which was heavy with the smell of Victorian-era stables and piles of rubbish lying in front of the streets, was the root cause of all the diseases. Diseases like plague and typhoid are regularly attacked in the city due to this unsanitary condition. Cholera germs from India also entered London during the Industrial Revolution, and the epidemic began. Is it just the stinky ‘miyazma’ or something else that is causing the huge population to turn into corpses in a few weeks? Dr. John Snow went out to find the answer to the question. 

Introduction to cholera

1813 John Snow was born when Napoleon’s Grande Army, defeated by General Winter, returned to France with its head bowed. But not as a child of a wealthy family, but as a coal miner in York who somehow managed to make ends meet. Since childhood, Snow has had a curious mind, and he has questions about everything. The mother, aggrieved by the boy’s questioning, decided not to let Snow’s hands get dirty with coal ink, so she enrolled her son in the school with the little money she had saved. After finishing school, 14-year-old Snow was sent to Newcastle to study medicine as a disciple of a doctor named William Hardcastle. And that’s when Snow had to deal with the nemesis cholera of his life.

John Snow was 18 when cholera struck England after evacuating villages in India, Russia, and Germany. In Newcastle, after London, when one by one people began to die, Hardcastle was no longer alone. The coal miners were sent to a slum, Snow alone, to cope with the situation.

Although not as deadly as smallpox or plague, cholera is then quite dangerous. The cholera bacterium has the ability to absorb all the water from the inside of any healthy person within a day and without any signal. On a typical day, when walking down the street, vomiting and diarrhea will suddenly start simultaneously. Up to 20 liters of water a day, the skin becomes sagging after leaving the body in this way, and liquid blood becomes sticky like jelly. After dehydration, one organ after another becomes inactive. Eventually, the person dies not from a direct attack of the disease but because his body has lost so much water that it cannot even produce enough plasma to survive.

But Snow, who had been a doctor’s disciple for four years, failed to cure the cholera patients by applying all the treatments. Cholera patients could not be stopped from eating anything from opium to hard herbs. Snow also tried to save himself by drinking water, but the first few hours of feeding seemed a bit healthy, but the patients began to turn into corpses after a few hours. Snow tried to cure dehydration, but even then, people did not know that diarrhea causes dehydration and dehydration of mineral salts. It was undiscovered until the twentieth century, and that’s why Snow couldn’t save his patients.

However, Snow kept notes of all the observations of his medical life. He noticed that workers inside the coal mines contracted cholera, far from graveyards, sewers, or dirty ponds. If cholera had originated in Miyazama, the people in these areas would have been more affected by cholera, not the coal miners far away. There is something else behind it, not Miyazama. Something that could easily spread from one person to another, ‘Senior doctors rejected Snow’s claim. And that is why the real cause of cholera remained unknown for a long time.

John Snow came to London to study medicine after working as a disciple of several other doctors. He got his General Practitioner’s License in just one year. He then went on to study for a bachelor’s and doctoral degree in apothecary and at the Royal College of Surgeons. Although so many degrees were not required to do medicine at that time. It was at this time that Snow began working on anesthesia. Before the snowfall, surgeons would pour chloroform onto the patient’s face, put it on a cloth, and wait a few hours before starting the operation, which often did not work properly. But Snow mixed the different ingredients together and came up with the most effective dose of anesthesia. His anesthesia was more effective than the others, so much so that he even had the task of anesthetizing Queen Victoria twice.

The second attack

Despite working under anesthesia, Snow did not forget the horrors of his childhood. Snow, a 35-year-old veteran doctor, contracted cholera for the second time in 1848. This time in the capital London. Snow realized that cholera does not spread because of any miasma, there is something else behind it. This time he got up to prove it. The first cholera patient in London found a doctor by taking advantage of the opportunity to be known to the medical community. It was learned that a sailor named John Harland had contracted cholera for the first time, and another person who rented the same house had contracted cholera 8 days after Harland’s death.

By adding two to two, Snow realized that cholera was not a measles-borne disease at all but that it spreads from person to person. But how to spread? This is what needs to be found out. Cholera patients were being caught all over London. Snow also talked to patients and doctors to gather information. You know, the pain starts from the stomach. From here, you can guess that the cause of the disease is probably eating or drinking something. If the disease was spread through polluted air, then the pain in the nose, throat, or lungs was supposed to start, wasn’t it?

He further added that diarrhea due to cholera is not only a symptom but also another means of spreading cholera! The term ‘germ’ has just begun to gain popularity among doctors. Snow also speculated that cholera was spread by a bacterium, probably through the water. He also experimented with being sure. He searched the streets of London and found two tube-wells, one of which was a little higher and had no connection to the street, while the other was a little lower, so the waste flowed to all the tube-wells. Cholera patients were compared with people who drank water from two tube wells. Almost everyone who drank from the second tube well was infected with cholera, while only one person who drank from the first tube well was found to be infected with cholera.

Snow wrote the results of his experiments, made a booklet, and spread it all over London that cholera spreads through water. But no one wanted to believe just seeing the results of this test, and others also avoided Snow’s claim. Snow’s failure to convince his superiors was nothing short of frustrating, but he did not give up. Decided to leave after seeing the end of it.

1854 Cholera epidemic

In 1850, Snow and several other doctors and researchers formed the Epidemiological Society of London. It is one of the oldest research institutes globally for scientific research on the causes of diseases and the development of antidotes. “How does the disease spread? How do disease germs reproduce? What causes epidemics? How can this be prevented? ” These were the subjects of the organization’s research. So when cholera struck again in London in 1854, Snow took to the field with all kinds of preparations to prove that cholera spreads through water.

But when Snow started collecting information about the person who died of cholera, he realized that there was no section in this information! Whether it is rich-poor, old-child, male-female or person of different area, age-gender-economic or social influence or position, any person is dying of cholera at any time! Less is one place in the city or more in another, and he did not find any such pattern. The people of London also began to think that it was divine wrath or a lottery test. But Snow is reluctant to admit it, and there must be some pattern hidden in it. 

Snow knew that cholera spread through the water, and he was able to satisfy himself by experimenting with tube wells. Still, there is even greater evidence to explain it to his superiors. He ran to the Municipal Records Office to find out the water supply of every house in London, and he found the original evidence in the records!

In the part of London where he worked, only two companies supplied water to all the houses. One is Southwark & ​​Vauxhall (S&V) Water Company, and the other is Lambeth Company. Both companies collect water from the river Thames, but from two parts of the river, and this is the main problem.

Under the house in London at that time, there was not only a special hole filled with excrement but also a drainage system so that it would not accumulate in the hole. And these wastes go directly to the river Thames, from where the drinking water is supplied! The S&V Company’s pipes collect water from where the waste is dumped. The Lambeth Company, on the other hand, recently moved their pipes further away, where the amount of waste is less. Snow got the material to run his experiment, he roughly divided the population of London. One portion is supplied with London wastewater, including the waste of cholera patients. On the other hand, the amount of such contaminated water is relatively low.

Snow at first thought it would be very easy to gather information. Go to each house and hear which company’s water is supplied to his house. But he made a mistake while collecting. Tenants don’t even have to know, and even landlords don’t remember which company they contracted with when building the house. Snow was disappointed again. Eventually, he got another new idea, and he started doing chemical analysis of the water of two companies. You see, the amount of salt in the water of S&V company is 4 times more than Lambeth!

This time, he compared the water of the two companies with the water of the houses where cholera patients have been identified. Seeing the test results, John Snow was convinced that this time the officials must believe that cholera is spread through water. Because the number of deaths due to the drinking water of S&V company is 38 as compared to the death of 6 people who drank the water of Lambeth company! Snow might have run the test in more detail if he had had a few more weeks, but the cholera struck again. Even if you do research, you can’t avoid medical responsibilities anymore. At first, he heard some small rumors of death due to cholera, but he did not pay much attention.

September 4. As soon as the newspaper was opened in the morning, Snow saw a large caption in the newspaper, and Even the coffin had to be pushed into the car. London has never seen such a bad situation since the plague. ” The name of the area, ‘Broad Street.

Broad Street Pump 

Cholera has spread from head to toe on Broad Street. The death toll continued to rise as the screams of the victims reached the ears of John Snow, who was walking down the road through the thin walls. There was no response even after knocking on the door of the house, none of the few houses survived, and many people left the area with their families for fear of cholera. As time goes on, gathering information in his hands is getting less and less. There is another place in front of it, the Registrar General’s Office, where you can find information on cholera deaths. At noon, Snow collected the addresses of all those who had died of cholera from the office. The house on both sides of the road shook, and Snow did not get an answer and kept thinking about how to solve it. And that’s when the idea of ​​drawing a road map and understanding the pattern of the dead came to his mind. And that is what has immortalized him in the world of data visualization.

Snow continued to draw spots according to the number of cholera patients by drawing a map centering on Broad Street. Gradually a pattern emerged on the map. Cholera deaths are highest in homes near the Broad Street pump. The farther the house is from the pump, the lower the mortality rate. But Snow knew that the believers in Miyazama could not be satisfied with this. He also included the area of ​​two more pumps closest to Broad Street in the map and calculated that the houses near the pumps on Broad Street had a higher mortality rate than the other two pumps.

Snow was looking for more flawless evidence. He got both the proofs by looking at the map. The huge factory at the corner of Portland Street is packed with 535 workers. According to estimates, 10 times more people will die there. But surprisingly, none of the factories was infected with cholera! Snow ran to the factory and found his desired proof. Inside the factory, there is a pump of its own, and it belongs to Grand Junction Water Works Company. From previous research, Snow already knew that the company’s water was safe. Snow rushed to the brewery on Broad Street to get the last clue, and there he found no cause for cholera. None of the brewery workers drink water. Their only drink to quench their thirst is a beer produced in the brewery!

All of Snow’s evidence was matched, and this time his work was successful only if he could convince local health officials. But Snow took two more days. During these two days, the person suffering from cholera, the deceased’s family members, and the doctor who gave the treatment of them were interviewed, and their information was matched with their statements. After all, Snow presented all his evidence at a meeting of health officials. Unable to break Snow’s conclusive evidence, they agreed to open the Broad Street pump. The handle of the Broad Street pump was removed the next morning.

Within four days of removing the handle, the number of new victims on Broad Street dropped to zero. Outbreaks appear to be exacerbated in other parts of London. The handle of the Broad Street pump was re-installed, and human life became normal. A new board has been set up to investigate the cause of cholera. There was speculation among the people as to why this epidemic had started. From divine wrath to the immorality of poor people, many gossips and rumors spread throughout London.

Another, like Snow, became interested in finding out the cause, and he was Henry Whitehead, a local pastor. One rumor after another, he kept coming out. He thought that the solution of Snow’s handle was also a coincidence. Because people have been drinking water from the Broad Street pump for a long time, it is water drawn directly from the depths of the soil, not water supplied by any company. Cholera has never been seen before, but why did cholera spread there at that time?

Whitehead explored his local influence to do more in-depth research. After getting acquainted with Snow, he also did not find any defects in Snow’s observation. The two again appeared in the registrar’s office. A young girl from the Lewis family died of cholera shortly before the outbreak began on Broad Street. Whitehead ran to talk to the baby’s mother. Sarah Lewis said her baby’s diaper was thrown in the excrement hole. Whitehead spoke to authorities and arranged for a hole test. Examination revealed that the improperly made hole had broken and merged with the connection of the Broad Street pump just 2 meters away! And that’s how the main cause of the cholera epidemic came out. 

After this discovery, the sanitary movement started in England. London’s sewerage system is overhauled. Excavation holes were removed, and modern pipes were installed, bringing every house in London into the sewer network. The tunnel underground in London required 31 million bricks and 13,000 miles of pipe, half the earth’s circumference!

After 1854, there was only one more cholera outbreak in London, at a place in the city where sewers had not been laid. Fortunately, swift action was taken to stop the cholera in the service, and he was the person in the registrar’s office to whom Snow regularly ran to find government information. In any case, modern London stands on top of this sewer system. That sewer, built 150 years ago today, is still working behind the scenes, removing London’s rubbish. The city had to be rebuilt to accommodate modern sewers in other European cities, and Chicago had to be raised 14 feet just to install sewer pipes below the city. And modern civilization has developed on this sewer pipe.