Pneumonia Virus of Mice (PVM)

RNA virus, enveloped.
 
Prevalence
Rare in laboratory mice and rats. Uncommon in wild mice.
 
Diagnosis
Serology or PCR.
 
Disease
No clinical signs in immunocompetent mice. A progressive interstitial pneumonia with wasting is seen in immunodeficient mice. Immunodeficient mice are persistently infected, develop progressive pneumonia, can lose weight and develop dyspnoea. In rats no clinical signs are seen, however microscopic lesions include interstitial pneumonitis and an acute, multifocal, nonsuppurative vasculitis.
 
Screening
Regular serological testing of resident animals and quarantine of suspect incoming animals.
 
Transmission
Transmission is by aerosol and direct contact with respiratory secretions.
 
Durability
PVM is not stable in the environment, losing 99% infectivity at room temperature in an hour.
 
Significance
In immunocompetent animals PVM unlikely to interfere with research. In immunodeficient animals, the progressive wasting disease associated with pulmonary dysfunction shortens lifespan and renders these animals unsuitable for research.
 
Control
Caesarian derivation and barrier maintenance have proven successful. The transmission of PVM can be limited by the use of cages with filter covers.
 
Reading
  • Infectious Diseases of Mice and Rats. National Research Council 1991.
  • Charles River Laboratories website, www.criver.com
  • University of Missouri, Research Animal Diagnostic Laboratory website, www.radil.missouri.edu