| genomic sequence of chorioallantois vaccinia virus ankara, the ancestor of modified vaccinia virus ankara. | chorioallantois vaccinia virus ankara (cva) is the parental virus of modified vaccinia virus ankara (mva), which was derived from cva by more than 570 passages in chicken embryo fibroblasts (cef). mva became severely host-cell-restricted to avian cells and has strongly diminished virulence in mammalian hosts, while maintaining good immunogenicity. we determined the complete coding sequence of the parental cva and mapped the exact positions of the six major deletions that emerged in the mva genom ... | 2007 | 18024893 |