[Centenary of the discovery of yellow fever virus and its transmission by a mosquito (Cuba 1900-1901)].

During the 17th, 18th and 19th centuries, yellow fever has been an ordinary scourge in American cities. In the early part of the 20th century, a main discovery has been achieved in Havana city, Cuba, leading to direct consequences for tropical medicine, public health and virology. 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. The idea that vomito negro would be spread by mosquito bites was not a new one. It has already been postulated, since 1881, by Carlos Finlay, a Cuban physician, who has attempted to prove experimentally his hypothesis in human beings, but without real success. The U.S. Army commission quickly demonstrated two essential facts ignored by C. Finlay, which explained his failure. To be able to transmit yellow fever, Ae. aegypti had to bite a patient during the first three days of the disease (viraemia), and then, a delay of about 12 days was necessary before the mosquito would be ready to transmit the disease to a non immune human (the virus replication time inside the insect). Since the role of mosquito in spreading yellow fever was established, an efficient means to fight the scourge was available, i.e., the mosquito extermination. This concept was quickly applied leading to the complete clean up of Cuba (1901) and the Panama isthmus (1907).