A poxvirus was isolated from a six-year-old girl. The comparative analyses of the genome of this isolate (H-CP-LSax) which were carried out using the restriction endonucleases BamHI, HindIII, KpnI, MluI, NcoI, SacI, and SmaI revealed that this isolate is a member of the genus orthopoxvirus. Since the girl had never been vaccinated against smallpox, and had close contact to domestic animals, including cats, rabbits and guinea pigs, the genome of H-CP-LSax virus was genetically analysed in comparison with other known orthopoxviruses. The analysis demonstrates clearly that the HindIII cleavage pattern of H-CP-LSax DNA is different from the HindIII DNA cleavage patterns of vaccinia virus, cowpox virus, rabbit poxvirus, cat poxvirus, ectromelia virus, and okapi poxvirus. Surprisingly, it was found that the HindIII and SmaI cleavage patterns of the DNA of one out of six elephant poxviruses which were analysed under the same conditions were virtually identical to the HindIII and SmaI cleavage patterns of H-CP-LSax DNA. Although SmaI and HindIII digestion of both virus genomes gave the same fragment patterns, the viral DNAs can be distinguished from each other by the restriction endonucleases SacI, BamHI, and KpnI, which also show high similarities in the fragmentation patterns of both viruses. The results obtained in this study indicate three possibilities concerning the origin of H-CP-LSax virus. Firstly that the H-CP-LSax virus originated from an unknown animal species. Secondly, that this virus is a variant of elephant poxvirus in which the HindIII and SmaI sites are extremely conserved, and finally that H-CP-LSax can be a recombinant virus of unknown origin.