About 25 strains have been reported. Field isolates often differ more or less from these. Strains differ in tropisms, tendency to disseminate, and virulence. Enterotropic strains replicate initially in the intestinal epithelium tend not to disseminate, and usually are only weakly virulent. Some strains of MHV are readily cultivated, whereas others are very difficult.
Enterotropic strains tend to be the most difficult to culture.
Infectivity depends on the envelope, so these viruses are very susceptible to disinfectants, especially those with detergent activity. Epizootiology Return to top Mus musculus is the natural host. Suckling rats inoculated experimentally had transient replication in nasal mucosa and seroconversion but no clinical disease. Deer mice seroconverted but had no clinical disease. MHV is extremely contagious and of all mouse infectious agents is probably the single most difficult agent to control.