University of Virginia Historical Collections at the Claude Moore Health Sciences Library

Walter Reed and Yellow Fever

Walter Reed’s Experiment to Determine if Malaria Is Transmitted by Mosquitoes, Infected Air, or Infected Bedding

Dr. Walter Reed drew this diagram of Building Two in a letter to his wife, Emilie, in December of 1900. Historical Collections & Services, Claude Moore Health Sciences Library, University of Virginia.

Dr. Walter Reed and his colleagues designed an elegant experiment in 1900 to prove how yellow fever is transmitted—and particularly whether the theory of Dr. Carlos Finlay, a physician in Cuba, was correct.

Yellow fever is a viral, hemorrhagic disease that caused deadly epidemics for thousands of years and still kills 30,000 people a year.

The Question: They wanted to prove which of three theories of transmission was correct:

Experimental design: The researchers built two 14’x20’ buildings: one tested the soiled-bedding theory; the other one tested both the infected-air and mosquito theories. A wire screen divided the second building into two rooms: in Side A, infected mosquitoes bit volunteers, while volunteers in Side B were not bitten but shared the same air.

Results: Only the volunteers bitten by infected mosquitoes became ill with yellow fever.

Note: In the 1930s, a vaccine was developed for yellow fever.

Further Information:


Notice: This exhibit was created by Normajean N. Hultman, Historical Collections Assistant. For permission to reproduce any of the text or those images owned by Historical Collections and Services or to make comments or suggestions, please contact a member of Historical Collections.