Lower Mississippi Valley yellow fever epidemic of 1878

In 1878, a severe yellow fever epidemic swept through the lower Mississippi Valley.

During the American Civil War, Union army troops in New Orleans feared that there would be an outbreak of yellow fever in the occupied city, and reacted by introducing sanitation and quarantine procedures in 1862. In 1877, the United States federal government pulled the federal troops out of New Orleans, directly causing a relaxation in the city's sanitation policies. The yellow fever outbreak had started by March 1878, and it was thought to be connected to an ongoing yellow fever outbreak in Havana. The epidemic may have spread from Cuban war refugees who were fleeing from the Ten Years' War in Cuba.

During the epidemic, tens of thousands of people fled from the stricken cities of New Orleans, Vicksburg, and Memphis. The safety policies to combat the spread of the epidemic included ordering the steamboats to be tied up in order to reduce the amount of travel along the Mississippi River, the halting of the railroad lines, and the layoff of all associated workers. This resulted in a massive rise in unemployment. It was estimated that 15,000 heads of households were unemployed within New Orleans itself, and a total of over 100,000 persons were in dire financial need.