IMMUNOLOGY

Detailed explanation-1: -There, the U.S. Army yellow fever commission headed by Walter Reed proved that yellow fever was a viral disease transmitted by a specific mosquito, Stegomyia fasciata, in fact Aedes aegypti L.

Detailed explanation-2: -The tiger mosquito is a vector for 20 diseases, including yellow fever, Rift Valley fever, West Nile virus and Japanese encephalitis virus.

Detailed explanation-3: -The mosquito vector was likely introduced to the U.S. via water barrels on trade ships arriving from countries with endemic yellow fever. The virus followed when slaves from areas with endemic disease arrived. The hungry mosquitos then spread the virus from infected to uninfected in the New World.