Transmission of Canine Distemper
Infected dogs shed the virus through bodily secretions and excretions, especially respiratory secretions. The primary mode of transmission is airborne viral particles that dogs breathe in. Dogs in recovery may continue to shed the virus for several weeks after symptoms disappear, but they no longer shed the virus once they are fully recovered.
It is possible for humans to contract an asymptomatic (subclinical) CDV infection. Anyone who has been immunized against measles (a related virus) is protected against CDV as well.