The nasal secretion and serum antibody response of lambs following vaccination and aerosol challenge with parainfluenza 3 virus.

The nasal and serum neutralising antibody responses of lambs was compared following vaccination with live or inactivated parainfluenza 3 (PI 3) virus by either intramuscular (IM) or intranasal (IN) routes. Nasal antibody was only detected following inoculation of live virus IN or inactivated virus in Freund's complete adjuvant (FCA) IM. Immunity to aerosol challenge, as assessed by viral shedding from the nose, was conferred by (1) live virus administered by either route, (2) two IM inoculations of inactivated virus in FCA, and (3) one IM injection of inactivated virus in FCA followed by IN instillation of inactivated virus.