The fourth cholera pandemic of the 19th century began in the

Ganges Delta The Ganges Delta (also known the Ganges-Brahmaputra Delta, the Sundarbans Delta or the Bengal Delta) is a river delta predominantly covering the Bengal region of the Indian subcontinent, consisting of Bangladesh and the Indian state of West Be ...

of the

Bengal Bengal ( ) is a Historical geography, historical geographical, ethnolinguistic and cultural term referring to a region in the Eastern South Asia, eastern part of the Indian subcontinent at the apex of the Bay of Bengal. The region of Benga ...

region and traveled with Muslim pilgrims to Mecca. In its first year, the epidemic claimed 30,000 of 90,000 pilgrims. Cholera spread throughout the

Middle East The Middle East (term originally coined in English language) is a geopolitical region encompassing the Arabian Peninsula, the Levant, Turkey, Egypt, Iran, and Iraq. The term came into widespread usage by the United Kingdom and western Eur ...

and was carried to the

Russian Empire The Russian Empire was an empire that spanned most of northern Eurasia from its establishment in November 1721 until the proclamation of the Russian Republic in September 1917. At its height in the late 19th century, it covered about , roughl ...

, Europe, Africa, and North America, in each case spreading via travelers from

port A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Hamburg, Manch ...

cities and along inland waterways. In 1866, there was a localized epidemic in the East End of London, primarily because the local section of the

London sewerage system The London sewer system is part of the water infrastructure serving London, England. The modern system was developed during the late 19th century, and as London has grown the system has been expanded. It is currently owned and operated by Thame ...

was still under construction and this region of London was experiencing

overcrowding Overcrowding or crowding is the condition where more people are located within a given space than is considered tolerable from a safety and health perspective. Safety and health perspectives depend on current environments and on local cultural ...

. The 1870s North American cholera outbreak spread from

New Orleans New Orleans (commonly known as NOLA or The Big Easy among other nicknames) is a Consolidated city-county, consolidated city-parish located along the Mississippi River in the U.S. state of Louisiana. With a population of 383,997 at the 2020 ...

via passengers along the

Mississippi River The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...

and to ports on its tributaries.

Cholera outbreaks associated with the Austro-Prussian War

The pandemic reached Northern Africa in 1865 and spread to

sub-Saharan Africa Sub-Saharan Africa is the area and regions of the continent of Africa that lie south of the Sahara. These include Central Africa, East Africa, Southern Africa, and West Africa. Geopolitically, in addition to the list of sovereign states and ...

, killing 70,000 in

Zanzibar Zanzibar is a Tanzanian archipelago off the coast of East Africa. It is located in the Indian Ocean, and consists of many small Island, islands and two large ones: Unguja (the main island, referred to informally as Zanzibar) and Pemba Island. ...

in 1869–70. Cholera claimed 90,000 lives in Russia in 1866. The epidemic of cholera that spread with the

Austro-Prussian War The Austro-Prussian War (German: ''Preußisch-Österreichischer Krieg''), also known by many other names,Seven Weeks' War, German Civil War, Second War of Unification, Brothers War or Fraternal War, known in Germany as ("German War"), ''Deutsc ...

(1866) is estimated to have taken 165,000 lives in the

Austrian Empire The Austrian Empire, officially known as the Empire of Austria, was a Multinational state, multinational European Great Powers, great power from 1804 to 1867, created by proclamation out of the Habsburg monarchy, realms of the Habsburgs. Duri ...

, including 30,000 in

Hungary Hungary is a landlocked country in Central Europe. Spanning much of the Pannonian Basin, Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the south, Croatia and ...

, 30,000 in

Belgium Belgium, officially the Kingdom of Belgium, is a country in Northwestern Europe. Situated in a coastal lowland region known as the Low Countries, it is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeas ...

, and 20,000 in the

Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

Localized epidemic in the East End of London

In June 1866, a localized epidemic in the East End of London claimed 5,596 lives, just as the city was completing construction of its major sewage and water treatment systems; the East End section was not quite complete. It was also caused by the city's

in the East End, which helped the disease to spread more quickly in the area. Epidemiologist

William Farr William Farr Order of the Bath, CB (30 November 1807 – 14 April 1883) was a British epidemiologist, regarded as one of the founders of medical statistics. Early life William Farr was born in Kenley, Shropshire, to poor parents. He was effec ...

identified the East London Water Company as the source of the contamination. Farr made use of prior work by

John Snow John Snow (15 March 1813 – 16 June 1858) was an English physician and a leader in the development of anaesthesia and medical hygiene. He is considered one of the founders of modern epidemiology and early germ theory, in part because of hi ...

and others, pointing to contaminated drinking water as the likely cause of cholera in an 1854 outbreak. In the same year, the use of contaminated canal water in local water works caused a minor outbreak at Ystalyfera in

South Wales South Wales ( ) is a Regions of Wales, loosely defined region of Wales bordered by England to the east and mid Wales to the north. Generally considered to include the Historic counties of Wales, historic counties of Glamorgan and Monmouthshire ( ...

. Workers associated with the company, and their families, were most affected, and 119 died.

New York City outbreak and creation of the New York Metropolitan Board of Health

The deaths of more than 1,100 people in New York City in 1866 resulted in the establishment of the New York Metropolitan Board of Health.

1870s North American outbreak spreading from New Orleans

In 1867,

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

lost 113,000 to cholera, and 80,000 died of the disease in

Algeria Algeria, officially the People's Democratic Republic of Algeria, is a country in the Maghreb region of North Africa. It is bordered to Algeria–Tunisia border, the northeast by Tunisia; to Algeria–Libya border, the east by Libya; to Alger ...

. Outbreaks in North America in the 1870s killed some 50,000 Americans as cholera spread from