“…Historically, differentiation of OPVs into single species has been achieved by biological means, such as pock morphology on the chorioallantoic membrane or ceiling growth temperature, because serological tests proved to be of limited value (3). DNA maps and several other molecular biologic features, including full genome sequencing, have been applied and have provided definitive information for virus classification (4,24,25,26). Various PCR methods have been used to identify and subtype the available OPVs by using consensus primers combined with restriction cleavage and/or sequencing of amplicons (6,10,13,18,23) or oligonucleotidebased microchip technology (11,12,20).…”