Walter Reed was a U.S. Army pathologist and bacteriologist who led the experiments that proved that yellow fever is transmitted by mosquito bite.
During the Spanish-American War, Walter Reed investigated the spread of typhoid fever in military camps. His report revealed new facts regarding this disease and was a brilliant investigation in epidemiology. He then turned his attention to yellow fever and determined that it could not be spread via clothing, bedding etc. and only by mosquito bites, which led to stopping the deadly disease.