Yellow fever in Buenos Aires the mosquito "Aedes aegypti", which was responsible of transmitting Yellow Fever. A witness to the epidemic of 1871, named Mardoqueo Navarro, wrote on April 13 the following description in his diary: Since 1881, thanks to Cuban physician Carlos Finlay, it was known that the transmitting agent of Yellow Fever was mosquito "Aedes aegypti". Before that discovery, doctors attributed the cause of many epidemics to what they called "miasmas" floating in the air. Yellow Fever (or "black vomit", as it was called due to bleeding that occurs in the gastrointestinal) caused an epidemic in Buenos Aires in 1852. However, by a
Yellow fever disease from nonhuman primates to humans. The virus is thought to have originated in East or Central Africa and spread from there to West Africa. As it was endemic in Africa, the natives had developed some immunity to it. When an outbreak of yellow fever would occur in an African village where colonists resided, most Europeans died, while the native population usually suffered nonlethal symptoms resembling influenza. This phenomenon, in which certain populations develop immunity to yellow fever due to prolonged exposure in their childhood, is known as acquired immunity. The virus, as well as the vector "A. aegypti," were