χολέρα

Choléra in Greek comes from cholé (bile). The Greeks used the word for any severe gastrointestinal illness involving vomiting and diarrhea, which they attributed to a disturbance of yellow bile — one of the four humors. The connection was observational: bile is yellow-green, and patients with severe gastroenteritis sometimes vomit bile. The theory was wrong, but the observation was accurate.

The disease now called cholera — caused by the bacterium Vibrio cholerae — is a specific waterborne infection distinct from what the Greeks described. Asiatic cholera, as it was called in the nineteenth century, reached Europe in the 1830s through trade routes from the Indian subcontinent. Seven global cholera pandemics have occurred since 1817. The disease spreads through water contaminated with infected fecal matter. It can kill within hours through dehydration.

John Snow — a London physician — traced a cholera outbreak in 1854 to the Broad Street pump in Soho. By mapping cases, he demonstrated that cholera was waterborne, not airborne as the prevailing 'miasma theory' held. He removed the pump handle. The outbreak subsided. Snow is now considered the father of epidemiology. The pump handle is a symbol of public health. The Greek bile theory was replaced by germ theory.

Cholera persists. The seventh pandemic, caused by Vibrio cholerae O1 biotype El Tor, has been ongoing since 1961. Haiti experienced a devastating outbreak after the 2010 earthquake. Yemen suffered the largest recorded outbreak in 2016-2017. The disease is now entirely preventable with clean water and sanitation. It kills because those things are absent, not because they are impossible.