During the eighteenth and nineteenth centuries, the United States, Caribbean, and South America experienced several major outbreaks of yellow fever, devastating local populations. Yellow fever takes its name from the yellow-ish color of affected patients’ skin and eyes. The virus affects multiple organ systems and causes internal bleeding; it can be fatal. Yellow fever broke out in Boston in 1693, Philadelphia in 1793 and Norfolk, Virginia in 1855, but the worst American outbreak of yellow fever occurred in the Mississippi River Valley in 1878.
Over the course of spring and summer of 1878, this region recorded 120,000 cases of yellow fever and between 13,000 and 20,000 deaths from the disease. The outbreak originated in New Orleans and spread up the Mississippi River and inland. The yellow fever epidemic impacted nearly all aspects of life in affected cities as residents fled, economies suffered, and thousands died. Memphis, Tennessee, was hit particularly hard, with over 20,000 residents fleeing the city. In the wake of the epidemic, cities implemented new public health and sanitation practices in an effort to prevent another outbreak. In 1900, researchers confirmed that yellow fever is transmitted by a species of mosquito, Aedes aegypti, which is native to Africa and flourishes in tropical and subtropical climates.