What is it?
Cholera has plagued us for a very long time, and it is still in many parts of the world. It is a bacteria that infects the gut. Upon drinking contaminated water, the infected person has cholera producing toxins in their intestines which make the body have explosive diarrhea… pretty gross, right? Because of this, someone may lose too much water, and this dehydration is what threatens an infected person’s life.
Cholera is spread through water contaminated with cholera-infected human waste. Back before the 1900’s, many cities were very cramped with people. The plumbing systems were also not affective, and so dirty water would not be disposed of properly. People would often throw their waste into the same river that they drank from!
Looking back on it, it seems pretty weird that this would be an issue. I mean, things seem so clean nowadays, right? But this all has to do with us not understanding back then how disease spread.
Cholera had a key role in changing our understanding of how diseases spread.
How did we fight it?
The Incorrect Miasma Theory of Disease
For years nobody knew how cholera spread. Originally, we believed in The Miasma Theory of Disease. It was thought that miasma – which is bad air – caused cholera. This miasma was thought to have come from the soil. So we tried to fight it by cleaning the air, providing good food, and encouraging good moral character. The moral character part is because people are superstitious, and often think that those who behave poorly got bad karma in catching cholera. This is all incorrect, and it turns out cholera is actually spread through germs.
Contact Tracing
In London 1854, a physician named John Snow came along and managed to find out where a cholera outbreak in a town was originating from. This was pretty revolutionary because he did not understand how cholera spread, but it did not matter. He invented contact tracing, which is used widely today to trace COVID outbreaks! Click here to learn more and play the contact tracing scavenger hunt!
A Major Breakthrough – The Germ Theory of Disease
Fast forward to 1883, along comes the invention of the microscope and a scientist named Robert Koch. With the microscope, he took a sample of contaminated water and he discovered a wiggly little guy that he called “vibrio cholerae”.
Fun fact! – “vibrio cholerae” literally translates to ‘I vibrate’, as Robert Koch saw them wiggling around under his microscope. Cool, right?
By isolating the microorganism, he was able to test whether it caused the disease cholera. This was done with what is now known as Koch’s postulates, which are used still for many other diseases like COVID-19 to find out their causes. Koch’s postulates were also used to figure out what caused Yellow Fever and Malaria.
This lead to the development of The Germ Theory of Disease to replace the miasma theory. This is the correct idea that infectious diseases are caused by small, practically invisible organisms such as virus’s, bacteria, and others. These organisms invade the body and reproduce using the bodies resources, with the goal of spreading to other people.
Koch was celebrated as a hero, as now we could change our systems to virtually remove chance of cholera infection in developed areas. Modern plumbing was developed, including the toilet, with sanitary systems now in place to cleanse all contaminated water before releasing it to the environment
People are Resistant to Change – The Stubborn Scientist Who Drank Cholera
Unfortunately, not everyone was super excited and resisted the positive change brought on by Robert Koch.
Max von Pettenkofer was a scientist who did a lot of his life work on The Miasma Theory of Disease. Understandably, he was upset that most of his work may become meaningless and so he refused to believe Robert Koch was correct.
Max was so unconvinced that he asked Robert to send him a sample of cholera, and then Max DRANK the sample! He drank millions of cholera bacteria to try and prove his point!
Max then wrote to Robert that he survived, shocking Robert because the sample he sent did indeed have the dangerous cholera bacteria in it. Why did he survive, then?
Robert actually had a bad case of cholera years earlier and this likely provided him with some immunity to the bacteria so he did not die upon drinking the cholera sample. In addition to this, some sources say Max actually did have a bad case of diarrhea after drinking the sample, although he would never admit this because he would never admit that Robert was right.
Vaccines
Cholera is not that big of a concern nowadays, largely in part due to better plumbing, infrastructure, and waste management in our societies. However, many areas around the world still have serious issues in battling cholera, and because of that, a vaccine is valuable to have.
When traveling to other countries, especially those where cholera is still a concern, it is common for people to take the traveler’s diarrhea vaccine, also known as Dukarol. It is about 40% effective and only for about 6 months, so it is not used in the same way the smallpox and measles vaccines have been.
Dukarol and related vaccines are thus used primarily for traveler’s into countries who have no natural immunity to cholera.
References
Kabir Shahjahan, & Alexander T. S. (2014). Critical Analysis of Compositions and Protective Efficacies of Oral Killed Cholera Vaccines. Clinical and Vaccine Immunology: CVI, 21(9), 1195–1205.
Miksanek, T. (2007). Twelve Diseases That Changed Our World. JAMA: The Journal of the American Medical Association, 298(24), 2914–2920.
Qadri, F., Wierzba, T. F., Ali, M., Chowdhury, F., Khan, A. I., Saha, A., Khan, I. A., Asaduzzaman, M., Akter, A., Khan, A., Begum, Y. A., Bhuiyan, T. R., Khanam, F., Chowdhury, M. I., Islam, T., Chowdhury, A. I., Rahman, A., Siddique, S. A., You, Y. A., … Clemens, J. D. (2016). Efficacy of a Single-Dose, Inactivated Oral Cholera Vaccine in Bangladesh. The New England Journal of Medicine, 374(18), 1723–1732.