History of cholera

Seven cholera pandemics have occurred in the past 200 years, with the first pandemic originating in India in 1817. The seventh cholera pandemic is officially a current pandemic and has been ongoing since 1961, according to a World Health Organization factsheet in March 2022. Additionally, there have been many documented major local cholera outbreaks, such as a 1991–1994 outbreak in South America and, more recently, the 2016–2021 Yemen cholera outbreak.

Although much is known about the mechanisms behind the spread of cholera, this has not led to a full understanding of what makes cholera outbreaks happen in some places and not others. Lack of treatment of human feces and lack of treatment of drinking water greatly facilitate its spread. Bodies of water have been found to serve as a reservoir, and seafood shipped long distances can spread the disease.

Between 1816 and 1923, the first six cholera pandemics occurred consecutively and continuously over time. Increased commerce, migration, and pilgrimage are credited for its transmission. Late in this period (particularly 1879–1883), major scientific breakthroughs toward the treatment of cholera develop: the first immunization by Pasteur, the development of the first cholera vaccine, and identification of the bacterium Vibrio cholerae by Filippo Pacini and Robert Koch. After a long hiatus, a seventh cholera pandemic spread in 1961. The pandemic subsided in the 1970s, but continued on a smaller scale. Outbreaks occur across the developing world to the current day. Epidemics occurred after wars, civil unrest, or natural disasters, when water and food supplies had become contaminated with Vibrio cholerae, and also due to crowded living conditions and poor sanitation.

Deaths in India between 1817 and 1860 in the first three pandemics of the nineteenth century, are estimated to have exceeded 15 million people. Another 23 million died between 1865 and 1917, during the next three pandemics. Cholera deaths in the Russian Empire during a similar time period exceeded 2 million.

The first cholera pandemic occurred in the Bengal region of India, near Calcutta (now Kolkata), starting in 1817 through 1824. The disease dispersed from India to Southeast Asia, the Middle East, Europe, and Eastern Africa through trade routes. The second pandemic lasted from 1826 to 1837 and particularly affected North America and Europe, due to the result of advancements in transportation and global trade, and increased human migration, including soldiers. The third pandemic erupted in 1846, persisted until 1860, extended to North Africa, and reached South America, for the first time specifically affecting Brazil. The fourth pandemic lasted from 1863 to 1875, and spread from India to Naples and Spain, and to the United States in 1873. The fifth pandemic was from 1881 to 1896 and started in India and spread to Europe, Asia, and South America. The sixth pandemic started in India and lasted from 1899 to 1923. These epidemics were less fatal due to a greater understanding of the cholera bacteria. Egypt, the Arabian peninsula, Persia, India, and the Philippines were hit hardest during these epidemics, while other areas, such as Germany in 1892 and Naples from 1910 to 1911, also suffered severe outbreaks. The seventh pandemic originated in 1961 in Indonesia and is marked by the emergence of a new strain, nicknamed El Tor, which still persists (as of 2019) in developing countries.

Cholera did not occur in the Americas for most of the 20th century after the early 1900s in New York City. It reappeared in the Caribbean toward the end of that century and seems likely to persist.

The first cholera pandemic, though previously restricted, began in Bengal, and then spread across India by 1820. Hundreds of thousands of Indians and ten thousand British troops died during this pandemic. The cholera outbreak extended as far as China, Indonesia (where more than 100,000 people succumbed on the island of Java alone) and the Caspian Sea in Europe, before receding. In 1821, it is estimated that up to 100,000 deaths occurred in Korea.

A second cholera pandemic reached Russia (see Cholera Riots), Hungary (about 100,000 deaths) and Germany in 1831; it killed 130,000 people in Egypt that year. In 1832 it reached London and the United Kingdom (where more than 55,000 people died) and Paris. In London, the disease claimed 6,536 victims and came to be known as "King Cholera"; in Paris, 20,000 died (of a population of 650,000), and total deaths in France amounted to 100,000. In 1833, a cholera epidemic killed many Pomo, which are a Native American tribe. The epidemic reached Quebec, Ontario, Nova Scotia, and New York in the same year, and the Pacific coast of North America by 1834. In the center of the country^{[clarification needed]}, it spread through the cities linked by the rivers and steamboat traffic.