The mechanisms behind the in vivo virulence of immunosuppressive wild-type Morbillivirus infections are still not fully understood. To investigate lymphotropism and host responses we have selected the natural host model of canine distemper virus (CDV) infection in mink. This model displays multisystemic infection similar to measles virus (MV) and rinderpest virus (RPV) infections in their susceptible natural hosts. The wild-type CDVs investigated provoked marked virulence differences inducing mild versus marked to severe acute disease. The mildly virulent wild-type induced transient lymphopenia despite the development of massive infection of peripheral blood mononuclear cells (PBMCs) exceeding that determined for the highly virulent wild-type, indicating an inverse relationship between acute virulence and the extent of viremia between the investigated wild-types. Single-cell cytokine production in PBMCs was investigated throughout the acute infections. We observed Th1- and Th2-type cytokine responses beginning in the prodromal phase, and late inflammatory responses were shared between the wild-type infections.