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Walter Reed & Mosquitoes

Walter Reed & Mosquitoes

Walter Reed is a pretty well-known name in our area, however, have you ever wondered why the military hospital in Bethesda is called the Walter Reed National Military Medical Center? This center happens to be named after an army pathologist and bacteriologist whose scientific discoveries had a significant impact on decreasing troop mortality during the Spanish American War. It wasn’t due to a strategic warfare plan or discovery of a new weapon. It was because of his research involving the pesky mosquito.

Walter Reed is credited with proving that the bite of a mosquito transmits yellow fever. This important finding has saved countless lives since 1900, and as such, we want to honor his legacy by sharing his story.

The Life of Walter Reed

Reed was born in 1851 in Virginia, the youngest child of a Methodist minister. In 1866, he and his family moved to Charlottesville so that he could study classics at the University of Virginia. After a short time, he decided instead to switch paths and study medicine. He graduated as a Doctor of Medicine in 1869 at the age of 17. Then, he became a student at Bellevue Medical College in New York to obtain a second medical degree. After taking several hospital positions, Reed decided that he wanted to join the military.

In 1875, he passed the Army Medical Corps exam and became a first lieutenant. He soon married and began his career in the army, moving around the country frequently. In 1898, during the Spanish American War, he chaired a committee that later published a report about typhoid fever, which was spreading in military camps. Following his work with typhoid fever, he began to investigate the problem of yellow fever.

The Discovery Linking Mosquitoes to Yellow Fever Transmission

During most of the 1800s, it was widely believed that yellow fever was spread by fomites: clothing or linens that had been used by someone with yellow fever. In 1881, Carlos Juan Finlay, a Cuban physician, and epidemiologist suggested that the disease was transmitted by insects, but he was never able to prove it. In 1896, Giuseppe Sanarelli, an Italian bacteriologist, posited that he had isolated the cause of yellow fever: an organism called Bacillus icteroides.

To find the truth, the US Army put Reed and another army physician, James Carroll, on the case. They also asked an assistant surgeon, Aristides Agramonte, to research the disease in Cuba. Agramonte found that Bacillus icteroides also affected patients who were suffering from diseases other than yellow fever, showing that it belonged to the hog cholera group of Bacillus, and was not the cause of yellow fever.

Reed was then appointed as the chairman of a commission tasked with investigating an outbreak of yellow fever in the US garrison at Havana. His fellow members were Carroll, Agramonte, and Jesse Lazear, a bacteriologist. After noticing a strange pattern in deaths in the garrison, Reed decided that the primary goal of the commission should be to figure out whether or not insects transmit the disease.

To accomplish this, they let an infected mosquito feed on Carroll, and he developed yellow fever. Later, Lazear was also bitten, and his case of yellow fever eventually killed him. In 1900, with the help of a series of controlled experiments, Reed officially proved that the bite of an infected Aedes aegypti mosquito — the same mosquito that carries Zika, then called Stegomyia fasciata — did cause yellow fever. They were able to corroborate this by infecting a volunteer with the disease by injecting blood from an infected patient.

The Impact of Knowing Mosquitoes Spread Yellow Fever

With these experiments, Reed was able to disprove the theory that yellow fever was spread by fomites, and he proved that mosquitoes were the disease vector. This information allowed US military engineers to eradicate yellow fever from Havana in 90 days.

Not only did his work immediately help reduce troop death due to illness, but Reed’s findings laid the foundations for all future research on mosquito-transmitted diseases. Without his work and the work of his contemporaries studying other diseases like malaria, we would not have been able to make such quick progress in fighting the spread of these epidemics.

A mosquito bite may be a major annoyance, but we can thank pioneers like Walter Reed for the fact that it’s no longer a death sentence here in the US. Countries all over the world are still working to fight well-known diseases like malaria and yellow fever, as well as newer ones like Zika. We at DC Mosquito Squad do our best to stop these diseases in their tracks by controlling mosquito populations in your backyard through our outdoor pest control services and by partnering with charities like Malaria No More to save lives. Visit to find out more about how you can help prevent malaria from taking the lives of children around the world.