The fourth cholera pandemic of the 19th century began in the Ganges Delta of the Bengal region and traveled with Muslim pilgrims to Mecca.

[4] The epidemic of cholera that spread with the Austro-Prussian War (1866) is estimated to have taken 165,000 lives in the Austrian Empire, including 30,000 each in Hungary and Belgium, and 20,000 in the Netherlands.

[6] It was also caused by the city's overcrowding in the East End, which helped the disease to spread more quickly in the area.

Farr made use of prior work by John Snow and others, pointing to contaminated drinking water as the likely cause of cholera in an 1854 outbreak.

[3] Outbreaks in North America in the 1870s killed some 50,000 Americans as cholera spread from New Orleans via passengers along the Mississippi River and to ports on its tributaries.