Etiology:  Sendai virus is an enveloped RNA paramyxovirus of the parainfluenza type 1 group.

Incidence:  The incidence of disease in research colonies is rare for Sendai virus.

Transmission: The primary route of infection is by aerosol or direct contact with infected animals during the first two weeks of infection when the virus is shed.  The disease is usually enzootic in a colony in which susceptible animals are regularly introduced.

Clinical Signs:  Sendai virus infections usually produce subclinical or mild disease.  Increased infant mortalities may be seen.  Chronic wasting syndrome and pneumonitis may be seen in nude rats.

Pathology:  Gross and histologic lesions associated with uncomplicated respiratory virus infection are uncommon.

Diagnosis: Diagnosis is made using serology (MFI, IFA) or PCR.