GENETIC-VARIATION AMONG STRAINS OF WILD-TYPE YELLOW-FEVER VIRUS FROM SENEGAL

We have examined and compared at the molecular level three strains of wild-type yellow fever (YF) virus isolated from Senegal in 1927, 1953 and 1965, termed French viscerotropic virus, Rendu and Dak1279 respect ively. Over the structural protein genes, Rendu differed from the othe r two strains by 8% at the nucleotide level. Rendu also differed antig enically, possessing a 'vaccine'-specific envelope (E) protein epitope (i.e. an epitope previously shown to be found on 17D and French neuro tropic vaccine viruses only and not wild-type strains of YF virus). Co nsequently, we propose that at least two distinct genotypes of wild-ty pe YF virus have been present in Senegal. Since Rendu virus was isolat ed from a fatal case of YF, it would indicate that the vaccine-specifi c epitope on the E protein is not associated with attenuation of the v iscerotropism of wild-type YF virus.