Orthopoxvirus species and strain differences in cell entry

► Recently isolated cowpox viruses enter cells via a low pH endocytic route. ► Monkeypox virus also enters cells through a low pH endocytic pathway. ► Some strains of vaccinia virus enter cells by a low pH route. ► Other vaccinia virus strains enter via a neutral pH, heparin-sensitive pathway. ► Deletion or swapping of A26 proteins did not alter route of vaccinia virus entry.