Cover of The Ghost Map
One of my favorite books is “The Ghost Map” , written by Steven Johnson. It chronicles the beginning of modern epidemiology (science that studies the spread of disease in humans) by following two different men of a learning- a scientist named John Snow and Reverend Henry Whitehead- during the London cholera epidemic of 1854. By investigating the cases of cholera in the neighborhood they served, they discovered its transmission via water and Dr. Snow created epidemiological mapping that is still used (albeit on computer) to this day. The book is extremely well written and engaging, so definitely check it out. (This post is just an attempt to give a crash course on the topic cause IT’S SUPER COOL GUYS)
19th Century science and medicine can be a distant concept at best so I will set the scene. *a-HEM*
We did not always believe germs caused disease. For over a thousand years doctors and scientists held to Miasma theory. In Western medicine it is attributed to Galen,a hugely influential Greek physician, surgeon, and philosopher born in AD 129 ,and it states that illness comes from “bad air” called “miasmata” or “night air”. The ancient Chinese and Indian societies also had the same concepts even earlier than the Greeks. All agreed that bad air’s source could be rotting organic matter, water containing waste of any kind, poor hygiene, and air pollution. Miasma made the individuals who inhaled it ill, and that individuals did not pass that illness on to other humans- only individuals who had direct contact with the bad air would fall ill. Western belief also held that bad air could come from the worms in ulcers of plague victims (I wish I were kidding).
poisonous air transmitting illness by Robert Seymour, 19th Century
[We now know that illness is caused by germs. Some illnesses are airborne, waterborne or transmitted by plants/animals/insects, and that almost all can be transmitted from person to person by various pathways. We’ve come a long way.]
tl;dr: Scientists and doctors adhered to the logic “If I have a strong negative visceral reaction to this smell, and the smell is near those who are ill, then the smell must be making these individuals ill.” (which, incidentally, I think is an example of Cum Hoc, Ergo Propter Hoc or the false cause fallacy) In the Ghost Map, Johnson hypothesizes that Miasma theory may have stuck around as long as it did because of our physiological and psychological relationship with our sense of smell. I would add that Miasma theory dovetailed nicely into the social and cultural views (held by many then, and still held by some people now) that those of the lower class would naturally be more ill and dirty as punishment for their moral failings. Luckily for us, Dr. Snow was a Miasma Theory skeptic, and this skepticism was ultimately what allowed him to make his groundbreaking discovery. The other difficulty in connecting germs with illness was that no one knew microbes existed until Anton van Leeuwenhoek and Robert Hooke’s first spotted them under microscopes in the 17th Century.
Re-occurring Cholera pandemics first began when the illness left the Indian subcontinent in 1817 (where the disease is thought to have originated and existed for thousands of years, the first written description is in Sanskrit from the 5th Century) spreading first to Russia, then Europe and the rest of the world. The London Cholera Outbreak of 1854 was part of a larger Cholera pandemic that lasted from 1839-1856. So by the time of Dr. Snow and the Reverend’s work, people were fairly familiar with the signs of Cholera, but no nearer to stopping it than they were in the previous pandemics.
Cholera is caused by a bacteria called Vibrio cholerae that lives in contaminated water (containing animal or human waste). Individuals become infected when they ingest contaminated water or if they ingest items that have come in contact with contaminated water such as shellfish or oysters. The symptoms of cholera are unique and dramatic- rapid and severe diarrhea and vomiting until the illness has taken its course. Choleric diarrhea is described as “rice water” and individuals may develop blue tinged skin as they lose fluids. The very young and very old have higher susceptibility, and it has a 50% fatality rate if individuals are not kept hydrated. There are vaccines for cholera as well as a cure- antibiotics or constant water and electrolytes- but since citizens of the 1800s had neither the knowledge nor the science, cholera became a devastating plague. (Historians believe cholera killed Tchaikovsky, King Charles X of France, and U.S. President James K. Polk)
The troubling thing is that something as easily treated and nasty as Cholera is still prevalent in the 21st Century. After the earthquake in Haiti in 2010, the government and the U.N. were unable to secure the water supply which led to the death of 8,000 people. Cholera will continue to kill 1,000 Haitians a year until it is eradicated from the country. Just yesterday South Sudan declared an outbreak that has infected 171 and killed 81. “Cholera broke out in the capital last year, five months into a civil war that is still ongoing over a year later. That outbreak was devastating infecting more than 6,000 people across 16 counties and resulted in the deaths of 167.” (Al Jazeera English)
As of 2010, it has caused 58,000–130,000 deaths a year(1). The scary and difficult part of this disease is that some strains can cause death in 2 hours and it infects individuals that are already in sometimes war-torn,devastated, under-served and impoverished communities.
What can be done? The consensus among the public health community is that prevention and preparedness on the part of governments is critical. Complete and thorough sanitation of drinking water that that is available to the entire population is essential. When or if there is a cholera outbreak, notifying the public, vaccinating and locating the source of the contamination is critical to slowing the spread. Continuing to aid countries in their improvement of infrastructure and communication of public health departments and health care communities in the developing world will be crucial to wiping out Cholera for good.
Want to know more about cholera? Check out the links below
Report on Cholera in India from World Health Organization
Harvard- Contagion: Historical Views of Diseases and Epidemics
Cholera Fact Sheet World Health Organization
Former U.S. President Bill Clinton and the Haiti Cholera Outbreak
Basic Principles of Epidemiology
1. Lozano R, Naghavi M, Foreman K, Lim S, Shibuya K, Aboyans V, Abraham J, Adair T, Aggarwal R, Ahn SY et al. (December 15, 2012). “Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010”. Lancet 380 (9859): 2095–128. doi:10.1016/S0140-6736(12)61728-0. PMID 23245604.