Differentiation of smallpox and camelpox viruses in cultures of human and monkey cells.

The cytopathic effect of smallpox and camelpox viruses has been compared in cell cultures derived from human and monkey tissues. The two viruses could easily be distinguished in HeLa, GMK-AH1, BSC-1 and WISH cells, camelpox producing multinucleate giant cells and smallpox producing rounding up of individual cells. In other cells (LLC-MK2, HEK and 2RhK) the differences were not so marked, and in some (VERO, HEL, K and HuTh) no differences were seen.