By the early nineteenth century, outbreaks of deadly disease had become commonplace in New York City. Smallpox, Yellow Fever, measles, and malaria recurrently plagued residents as they carved a city out of the marshes of Manhattan Island. New York's developing role as an entrepot for trade between the American interior and the Atlantic world contributed to the city's susceptibility to disease. Sailors and traders from far-off ports brought with them fresh strains of familiar diseases, and new settlers added to the city's woes in dealing with a rising tide of human waste and garbage. Most of these diseases were seasonal and epidemic: they usually would hit unexpectedly, run their course quickly and ferociously, and then disappear.

Cholera was among the most virulent infectious diseases to strike nineteenth-century New York. Transmitted by contaminated food and water, cholera causes diarrhea and vomiting so severe that death by dehydration is possible if the symptoms are left untreated. When the disease arrived in New York City in Summer 1832, after traveling over trade routes from India through Russia and Europe across the Atlantic to Canada and down the Hudson River Valley, thousands of New York City residents died within weeks. Cholera struck again in 1849 and 1866 before New Yorkers learned how to contain the disease. Measuring the reaction of New Yorkers to these increasingly traumatic public health disasters shows how understandings of disease were filtered through contemporary ideas about class and social relations, conceptions of immigrants, and thinking about the responsibilities of the city's government in issues of public health in mid-nineteenth century New York.