Reed Yellow Fever Commission

Havana averaged 462 deaths from yellow fever a year in the 1890s. Frustrated by its failure to control the disease, the US Army formed a Yellow Fever Commission in Cuba in May 1900, with Walter Reed in charge and James Carroll, Jesse Lazear and Aristides Agramonte as members. At the fringes of the profession, the Cuban physician Carlos Finlay had long argued that mosquitoes spread the disease.

The work turned deadly early. Lazear caught yellow fever on 18 September 1900 and died on 25 September. The commission then ran three kinds of experiment at Camp Lazear, near Havana. Of the volunteers bitten by mosquitoes that had fed on yellow fever patients, four developed the disease. Others were shut in a sealed room with bedding soiled by the excrement and dried blood of patients who had died, and wore their clothes; none caught it. Of four volunteers injected with blood from patients, three developed yellow fever.

None of the infected volunteers died during the study. The results supported Finlay, and the commission reported in 1900 that the mosquito now called Aedes aegypti carries the disease. The volunteers signed written contracts setting out the terms of their part in the study, and Spanish immigrants received copies in Spanish and English. The University of Virginia describes this as the first time in history that all the volunteers in an experiment were given written contracts.

William Gorgas, Havana's chief sanitary officer, had doubted the mosquito theory. After Camp Lazear he led a campaign against mosquitoes in 1901. Twelve yellow fever deaths were recorded in Havana in January and February 1901, and the last death of the US occupation came on 28 September 1901. The commission's letters and contracts are now in the Philip S. Hench Walter Reed Yellow Fever Collection at the University of Virginia.