Prolonged viral antigen retention in the brain of a gnotobiotic dog experimentally infected with canine distemper virus

Chronic canine distemper virus (CDV) infection, expressed as delayed-onset demyelinating encephalomyelitis (Old Dog Encephalitis, ODE) or as chronic polioencephalitis is a well known sequela to acute CDV infection, and may arise following and acute symptomatic episode, clinically inapparent infection, or vaccination. Delayed-onset encephalitis is distinguished by multiple sites of intracellular viral antigen deposition, which occur in the presence of an antiviral immune response. It is presumed that delayed manifestations of CDV encephalitis involve persistent viral infection, although in most naturally occurring cases re-exposure to wild type virus cannot be excluded. The authors discuss their experiments involving the prolonged retention of canine distemper virus antigens in the brain.