Etiology: Parainfluenza viruses (PI-1, -2 and -3) are enveloped RNA viruses.
Transmission: Transmission occurs by direct contact and aerosol.
Incidence: The incidence of infection with Parainfluenza viruses is rare.
Clinical signs: PI-1 (Sendai virus) produces transient infection and generally subclinical disease, but rhinitis has been noted in experimental infection.
PI-2 (SV5 virus) has only been documented by seroconversion.
PI-3 has been recovered from research guinea pigs and produces subclinical transient infection.
Diagnosis: Diagnosis is made by serology (MFI, IFA).