ABSTRACT
Nearly one hundred years ago, it was discovered that yellow fever, the protype flavivirus disease, was caused by a filterable virus and transmitted to humans by mosquitoes. It was the first member to be isolated in the flaviviridae family in 1927. The Flaviviridae obtain their name from “yellow” (flavus, Latin) fever. The Flaviviridae consist of positive-sense, singlestranded RNA viruses that are spherical in shape with a diameter of 40-60 nm (1). The flavivirus virion has a spherical nucleocapsid surrounded by a lipid bilayer envelope with small projections from the surface. The envelope proteins, E (envelope) and M (membrane), are embedded in the lipid layer. The E-protein contains the antigenic determinants for hemagglutination and most of the virus neutralizing antibodies. It also mediates virus-host cell binding.
