Parvoviruses (MVM and MPV)

Etiology: Parvoviruses of mice are single stranded nonenveloped DNA viruses of several species: Minute Virus of Mice (MVM) and Mouse Parvovirus (MPV).

Incidence:  The incidence of infection is uncommon.

Transmission: Mice are infected primarily by direct contact with virus shed in feces or urine. Parvoviruses are capable of surviving in the environment for extended periods of time (weeks), and fomites are a significant mode of transmission.  MVM and MPV can also be transmitted through the use of contaminated biological materials.

Clinical Signs: Naturally-occurring parvovirus infections do not produce clinical signs in either immunocompetent or most immunocompromised mice.  In immunocompetent mouse hosts, MVM appears to cause a short-lived infection while MPV causes persistent infection of lymphoid tissue (especially mesenteric lymph nodes).  Age and strain of mouse influence infectivity of parvovirus.  DBA and C57BL/6 mice appear resistant compared to ICR and BALB/c mice.

Pathology: Parvovirus infection does not cause lesions in mice.

Diagnosis: Identification of infected mice relies on serologic testing for parvoviral antibodies and amplification of parvoviral genome by PCR.  MFI and IFA are sensitive methods to screen for antibody to either or both parvoviruses depending on the test antigen. The viral protein, VP2, is antigenically distinct between MVM and MPV.  PCR of feces or mesenteric lymph node can be used to detect the virus in mice, and PCR can be used to screen samples for parvovirus in cultured cells or other biological materials.