Etiology:  Mouse thymic virus (MTV) is an enveloped DNA virus of the family Herpesviridae.

Incidence:  The incidence of infection is rare.

Transmission: Transmission occurs by direct contact with saliva.

Clinical Signs:  Spontaneous infections with MTV are asymptomatic.  Experimental infection in neonates less than 10 days of age causes immunosuppression.

Pathology: In mice inoculated before 10 days of age, characteristic lesions include intranuclear inclusions in thymocytes and thymic necrosis.

Diagnosis:  Diagnosis of MTV can be made using IFA or PCR.  Observation of thymic necrosis on histology may confirm diagnosis.