1. ^*Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA
2. ^‡National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA
3. ^§The Institute for Genomic Research, Gaithersburg, Maryland 20878, USA
4. ^†To whom correspondence should be addressed.

Abstract

SMALLPOX eradication culminated the most successful antimicrobial campaign in medical history¹. To characterize further the linear double-stranded DNA genome of the aetiological agent of smallpox, we have determined the entire nucleotide sequence of the highly virulent variola major virus, strain Bangladesh-1975 (VAR-BSH; 186,102 base pairs, 33.7% G + C; Genbank accession number, L22579). Here we highlight features of the molecule and focus on a few of the 187 putative proteins that probably contribute to pathogenicity and virus host-range properties. One hundred and fifty proteins were markedly similar to those of vaccinia virus (smallpox vaccine), for which a complete sequence has been reported^2,3 for strain Copenhagen (VAC-CPN; 191,636 base pairs, 33.3% G + C). The remaining 37 proteins reflected variola-specific sequences or open reading frame divergences for variant proteins, which are often truncated or elongated compared with their vaccinia counterparts.