Comparison of the genome DNA sequences of Bangladesh-1975 and India-1967 variola viruses.

The nucleotide sequences of genome DNAs and the deduced amino acid sequences of proteins from potential open reading frames (ORFs) of variola smallpox viruses from outbreaks in India in 1967 and in Bangladesh in 1975 have been compared and the analyses of the sequences are updated. Alignment of the DNAs revealed 99.3% base sequence identity. Of the 200 potential encoded proteins of each virus, 122 were identical, 42 showed substitution of a single amino acid, 11 showed two residues changes, and the remainder were more diverged. The variant proteins were encoded mainly in the near-terminal regions of each genome. The most conserved region between the variola DNAs included ORFs A33L to A49R, which is a relatively poorly conserved region compared with vaccinia virus.