Phylogenetic analysis reveals the emergence, evolution and dispersal of carnivore parvoviruses

Canine parvovirus (CPV), first recognized as an emerging virus of dogs in 1978, resulted from a successful cross-species transmission. CPV emerged from the endemic feline panleukopenia virus (FPV), or from a closely related parvovirus of another host. Here we refine our current understanding of the evolution and population dynamics of FPV and CPV. By analysing nearly full-length viral sequences we show that the majority of substitutions distinguishing CPV from FPV are located in the capsid protein gene, and that this gene is under positive selection in CPV, resulting in a significantly elevated rate of molecular evolution. This provides strong phylogenetic evidence for a prominent role of the viral capsid in host adaptation. In addition, an analysis of the population dynamics of more recent CPV reveals, on a global scale, a strongly spatially subdivided CPV population with little viral movement among countries and a relatively constant population size. Such limited viral migration contrasts with the global spread of the virus observed during the early phase of the CPV pandemic, but corresponds to the more endemic nature of current CPV infections.