Carroll, James (1854–1907)

English-born US physician who with US bacteriologist Walter Reed established that yellow fever is transmitted by mosquitoes.

Carroll and Reed were members of the Yellow Fever Commission established 1900 by the US government to investigate the causes of this disease, as thousands of US troops were dying of yellow fever in Cuba while fighting the Spanish. Reed discovered that yellow fever was transmitted via the mosquito parasite Aedes aegypti, and that the infectious agent had to develop within the mosquito for a number of days.

He proved his theories with a series of controlled experiments in which diseased and healthy human volunteers were bitten by infected mosquitoes. Carroll allowed himself to be bitten by a mosquito that had fed on a patient with the disease twelve days earlier. He became very ill, but made a good recovery; a colleague was not so fortunate and later died from the disease.

Carroll was born in Woolwich in the UK but emigrated to North America with his family as a child. He trained as a doctor before working as a surgeon with the US Army.