ABSTRACT
During the 17th, 18th, and 19th centuries, yellow fever was one of the most important epidemic diseases in tropical areas of the Americas and Africa. The discovery of jungle yellow fever in 1932 provided an explanation for such events and led Soper and Wilson13 to the conclusion that eradication of the urban vector was necessary to prevent epidemics. Serologic evidence for infection of wild vertebrate hosts is often extremely difficult to interpret because of cross reactions with other flaviviruses. The flaviviruses were originally placed together by Casals and Brown because of cross reactivity in the hemagglutination-inhibition test. Several workers have described a close antigenic relationship between yellow fever virus and certain African flaviviruses and have suggested their inclusion in a yellow fever complex. The recurrence of epizootic involving monkeys in a longitudinally studied area might afford a better opportunity for the assessment than a human epidemic.
