The virus is shed via urinary, fecal, and perhaps respiratory routes. Transmission is therefore most probably primarily direct, although extensive transmission studies have yet to be conducted. Transmission may also occur following experimental exposure to selected, infected T-cell lines. Natural infections of mice are generally asymptomatic and apathogenic, even for neonatal and immunocompromised mice. In immunocompetent mice, viral replication occurs in the pancreas, small intestine, lymphoid organs, and liver and may persist for several weeks.
Viral replication is more widespread in immunodeficient mice.
MPV-1 affects processes linked to cell proliferation. Reported effects include direct modulation and dysfunction of T lymphocytes and altered patterns of rejection of tumor and skin allografts. It is anticipated that additional effects will be reported as more studies are conducted on this important virus. Recently, a new parvovirus of rats, designated RPV-1, has been identified. To date, little is known about the virus.