Characterization of hepatitis B virus genotypes among Yucpa Indians in Venezuela.

The complete genome sequences of hepatitis B virus (HBV) from 12 HBV-infected Yucpa Indians of Venezuela, a group with highly endemic HBV, were amplified and sequenced. The 12 isolates were closely related to each other, with 98.6-100% nucleotide identity. A phylogenetic tree based on the complete genome indicated clearly that they were genotype F. Three individuals had evidence of infection with two different HBV deletion mutants. In two individuals, a three amino acid deletion was identified just prior to the 'a' determinant loop of the S region. A third individual was infected with virus that contained a complete core reading frame and a population that contained a deletion in the middle of the core region. These results indicate that genotype F HBV is present in the Venezuelan Yucpa Amerindians and the complete genome sequence allowed the identification of two unique deletion mutants in a limited set of samples.