Canine distemper virus (CDV) belongs to the genus Morbillivirus (measles-distemper-rinderpest group). All animals of the families Canidae (such as dog, fox, wolf), Procyonidae (such as raccoon and panda), Mustelidae (such as ferret, badger, marten) and Felidae (tiger, lion) can become infected. Canine distemper is enzootic worldwide. Transmission is oral or aerogenic via secretions and excretions of sick dogs or clinically healthy excretors. Intrauterine infections are also possible. Canine distemper is an acute to subacute, febrile general disease. A respiratory, an intestinal, a central nervous and a cutaneous course can be distinguished.
Virus excretion begins after approx. 7 days (up to 60 to 90 days p.i.), in the course of which a typical cyclic infection with leucocyte-associated (possibly also non-cell-bound) viraemia occurs. Depending on the ability of the immune system to produce neutralising antibodies, canine distemper can take a mild or fatal course.