RESUMEN
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).
Asunto(s)
Aedes , Fiebre Amarilla/historia , Virus de la Fiebre Amarilla , Animales , Cuba , Historia del Siglo XVII , Historia del Siglo XVIII , Historia del Siglo XIX , Historia del Siglo XX , Humanos , Insectos Vectores , Fiebre Amarilla/transmisión , Fiebre Amarilla/virologíaRESUMEN
In 1900 the role of a particular mosquito called Stegomyia fasciata in the transmission of yellow fever was proved by a board of American medical officers. This discovery was the beginning of several scientific missions in South America, mostly in Brazil. As yellow fever was increasing in its West African colonies, the French government decided to send a scientific mission to Rio de Janeiro, to find new ways of prevention against the disease. Under the authority of the Institut Pasteur, Paul-Louis Simond, who had just discovered the role of the flea in the transmission of plague, was designated to carry through this mission together with Emile Marchoux and Alexandre Salimbeni, eminent Pasteurians like him. From November 1901 to May 1905, the three men studied the epidemiological and clinical aspects of the disease in Rio. They worked on the intermediate host's entomology, the Stegomyia female mosquito, improving the knowledge of yellow fever and its means of transmission. They also realized experiments on 25 healthy volunteers, submitting them to the bite of infected mosquitoes. They were among the first to proceed to yellow féver vaccinations by means of virulent serum heated to 55 degrees C or filtered. Their work led to the establishment of new sanitary rules to prevent the spread of the disease. This contributed to the success of the "yellow fever campaign" initiated by Oswaldo Cruz in the town of Rio. One of the most original contribution of their studies was to show that the yellow fever agent (which was still unknown) could be transmitted from an infected female Stegomyia to its eggs and larvaes. After this mission, the French authorities were able to fight yellow fever efficiently in their African colonies as well as in the West Indies and French Guyana.
Asunto(s)
Fiebre Amarilla/historia , Animales , Brasil , Culicidae , Femenino , Francia , Historia del Siglo XX , Humanos , Insectos Vectores , Vacunas Virales/historia , Fiebre Amarilla/prevención & control , Fiebre Amarilla/transmisión , Virus de la Fiebre Amarilla/inmunologíaRESUMEN
Since 1958, the geographical distribution of Argentine hemorrhagic fever (AHF) has especially extended non only into the province of Buenos Aires but also towards the provinces of Santa Fe and Cordoba, leading to an estimated population at risk of about 1.2 M inhabitants. Recent epidemiological field studies has confirmed the major role of Calomys musculinus and C. laucha rodents in both transmission to man and conservation of Junin virus in nature. However, the human infection may result essentially from contacts with infected C. musculinus. Clinical condition of patients with AHF was greatly improved using AHF convalescent plasma and additional administration of vidarabin may still improve the results of treatment. A live attenuated vaccine, Candid No 1, is presently under evaluation in endemic foci of AHF. On the contrary Bolivian hemorrhagic fever (BHV) appears at present quite silent. A new disease resembling both AHF and BHF, the Venezuelan hemorrhagic fever, appeared in 1989 in the rural areas of central Llanos of Venezuela. The mortality was very high, reaching 23% or more among severely ill patients. The wild small rodents responsible for the disease were identified as Sigmodon alstoni and Zygotontomys brevicauda. Recent extension of agricultural practices and massive immigration may probably explain the recent emergence of this new viral zoonosis.