Acute hepatitis associated with mouse leukemia. V. The neurotropic properties of the causal virus

Area of Science:

• Virology
• Neuroscience
• Immunology

Background:

• Murine hepatitis virus (MHV) is a significant pathogen in mice.
• Understanding MHV neurotropism is crucial for disease management and research.
• Different MHV strains exhibit varying host specificities and pathogenicity.

Purpose of the Study:

• To investigate the neurotropic potential of different MHV strains (MHV (Pr) and MHV (C)) in mice.
• To compare the neuropathological effects of MHV (Pr) and MHV (C) in various mouse strains.
• To identify potential co-factors influencing MHV neurotropism and pathogenicity.

Main Methods:

• Intraperitoneal and intracerebral injections of MHV (Pr) and MHV (C) into Princeton, Swiss, and Balb C weanling mice.
• Pathological examination of cerebral tissues to assess neurotropism and lesions.
• Isolation and identification of viral agents and co-infecting organisms (e.g., Eperythrozoon coccoides, pleuropneumonia-like organism).

Main Results:

• MHV (Pr) demonstrated limited neurotropism, establishing in the brain with difficulty and causing minimal pathology, overshadowed by hepatitis.
• MHV (C) exhibited significant neurotropism, inducing severe leptomeningeal and encephalitic lesions, paralysis, and high mortality in Balb C and Swiss mice, but was inactive in Princeton mice.
• Co-infection with Eperythrozoon coccoides or isolation of a pleuropneumonia-like organism during MHV (C) passage suggested potential modulation of host response.

Conclusions:

• MHV (C) is significantly more neurotropic and pathogenic than MHV (Pr), causing severe central nervous system disease in susceptible mouse strains.
• Mouse strain background (Princeton, Swiss, Balb C) critically influences susceptibility to MHV neurotropism and disease.
• The study underscores the diverse neuroinvasive capabilities within the MHV family and the potential role of co-infections in modulating disease presentation.