Mouse adenoviruses are nonenveloped DNA viruses of the Mastadenovirus family. There are two strains of mouse adenovirus. Mouse adenovirus type 1 (MAdV-1) and mouse adenovirus type 2 (MAdV-2). MAdV-1 is transmitted through contact with infected urine. Mice that recover from acute infection shed MAdV-1 in the urine for prolonged periods (1-2 years) and viral DNA persists in brain, spleen and kidney for 1 year after experimental infection. Immunodeficient mice infected with MAdV-1 may also shed virus via fecal route. MAdV-2 is shed in feces; the virus is transmitted via the fecal-oral route.