Second, the strains present after 1999 either had one or the other of the two amino acid combinations in the CDV - H - protein commonly reported from CDV strains worldwide. (sciencedaily.com)
Furthermore, laboratory experiments demonstrated that strains with the rare amino acid combination 519I / 549H in the CDV - H - protein were significantly better at invading cells with lion or domestic cat receptors than cells with domestic dog receptors. (sciencedaily.com)