Fig. 2

Phylogenetic tree constructed from the alignment of complete H gene sequences obtained from GenBank, which represents all current CDV-described genotypes. 67 H sequences representing all genotypes were retrieved and aligned with ClustalW using MEGA 6 software. MEGA6.0 was also used for phylogeny inference according to the Maximum Likelihood algorithm method based on the Tamura 3-parameter model. The rate variation among sites was modeled using a gamma distribution (shape parameter = 5). The robustness of the hypothesis was examined using 1000 non-parametric bootstrap analyses. GenBank accession numbers of all isolates used to construct the tree are listed in Additional file 1: Table S1.