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 respectively. Over the structural protein genes, Rendu differed from the other two strains by 8% at the nucleotide level. Rendu also differed antigenically, possessing a 'vaccine'-specific envelope (E) protein epitope (i.e. an epitope previously shown to be found on 17D and French neurotropic vaccine viruses only and not wild-type strains of YF virus). Consequently, we propose that at least two distinct genotypes of wild-type YF virus have been present in Senegal. Since Rendu virus was isolated from a fatal case of YF, it would indicate that the vaccine-specific epitope on the E protein is not associated with attenuation of the viscerotropism of wild-type YF virus.