Yellow Fever: 100 Years of Discovery

Abstract

The article describes a series of experiments conducted to explore how yellow fever is propagated from individual to individual and how the contagium is spread within households. The study was conducted in an experimental sanitary station in Cuba, where exposures and movements could be completely controlled. During the investigation, 12 nonimmune persons underwent different exposures, including mosquitoes that had fed on yellow fever patients, blood from infected patients, and fomites belonging to infected patients.The study provided the following observations: (1) Aedes aegypti mosquitoes transferred the disease from an infected individual to a nonimmune person; (2) at least 12 days were needed for the extrinsic incubation period in the mosquito before it could transmit the infection; (3) yellow fever can be transferred to a nonimmune person from the blood of an infected individual taken during the first 2 days of the illness; (4) a filterable agent was responsible for infection; (5) the incubation period for humans ranged between 2 and 6 days; and (6) yellow fever cannot be transmitted by fomites nor spread in a house without the presence of mosquitoes. The most significant conclusion was that the “spread of yellow fever can be most effectually controlled by measures directed to the destruction of mosquitoes.”See PDF for full text of the original JAMA article.