Aspects of canine distemper virus and measles virus encephalomyelitis.

Canine distemper (CD) is a frequently fatal, systemic morbillivirus infection in the dog and other carnivores: encephalomyelitis is the common cause of death. Susceptibility to canine distemper virus (CDV) is now recognized in a wide range of non-domestic animals, most recently in captive lions, tigers and leopards. Furthermore, closely related viruses have produced CD-like diseases in marine mammals. CDV induces an inclusion-body encephalomyelitis in the dog and demyelination is often a conspicuous feature. Myelin injury is associated with the presence of virus but the mechanism of demyelination remains incompletely understood. Oligodendrocyte infection may be defective, as has been shown in vitro. CDV and measles virus (MV) produce similar systemic disorders in their respective hosts but differ markedly in the frequency of central nervous system (CNS) involvement, and in the pathogenesis of the more common neurological sequelae. Both CDV and MV have been considered as multiple sclerosis agents, and the association of CDV with other human disease has been suggested.