Muromegalovirus

Muromegalovirus, also known as murine cytomegalovirus (MCMV), is a species of herpesvirus in the genus Cytomegalovirus, family Herpesviridae, subfamily Betaherpesvirinae. It naturally infects mice and is widely used as a model to study cytomegalovirus biology and human CMV infection.

Muromegalovirus is an enveloped, icosahedral double-stranded DNA virus. The genome is roughly 235 kilobases and encodes more than 180 proteins. Replication occurs in the cell nucleus, and virions are released through budding from nuclear and cytoplasmic membranes. The virus establishes latency in the hematopoietic system and can reactivate under conditions of immune stress, reflecting key features of other cytomegaloviruses.

Host range and tropism: MCMV infects multiple tissues, including salivary glands, liver, lungs, spleen, and the gastrointestinal tract. Following primary infection, it typically becomes latent in myeloid cells and can reactivate during immunosuppression or inflammatory stimuli. Transmission occurs via direct contact, as well as secretions and bodily fluids, with congenital infection possible under certain circumstances.

Pathogenesis and disease: In healthy adult mice, infection is often subclinical. Neonatal or immunocompromised mice may develop organ inflammation such as interstitial pneumonia, hepatitis, or nephritis. While differences exist between murine and human CMV, MCMV exhibits similar viral entry, replication, and immune evasion strategies that make it a valuable comparative model.

Laboratory use and relevance: MCMV is a primary model for studying CMV transmission, latency, immune control, and antiviral strategies. Findings in this model help illuminate human CMV biology, though species-specific differences require careful extrapolation.

Taxonomy and history: Muromegalovirus is the ICTV-accepted species name corresponding to murine cytomegalovirus. It belongs to Betaherpesvirinae, genus Cytomegalovirus. Laboratory strains such as the Smith strain are widely used in research.