Isolation of low-virulent mouse hepatitis virus from nude mice with wasting syndrome and hepatitis

Area of Science:

• Virology
• Immunology
• Pathology

Background:

• Mouse hepatitis viruses (MHV) are known pathogens causing various diseases in rodents.
• Nude mice, lacking a thymus, have impaired T-cell immunity, making them susceptible to certain infections.
• Chronic hepatitis and wasting syndrome are observed in some immunodeficient mouse models.

Purpose of the Study:

• To isolate and characterize mouse hepatitis viruses from nude mice exhibiting specific clinical signs.
• To determine the pathogenicity of these isolated MHV strains in a susceptible mouse model.

Main Methods:

• Virus isolation was performed using DBT cell culture.
• Affected liver tissues from nude mice were used for isolation.
• Pathogenicity testing involved inoculating cortisone-treated and non-treated ICR weanling mice.

Main Results:

• Mouse hepatitis viruses were successfully isolated from the livers of nude mice with wasting syndrome and chronic hepatitis.
• The isolated MHV strains were pathogenic in cortisone-treated ICR weanling mice.
• Non-treated ICR weanling mice did not show disease upon inoculation with the same isolates.

Conclusions:

• Nude mice can harbor and shed pathogenic strains of mouse hepatitis virus.
• Cortisone treatment significantly increases the susceptibility of ICR weanling mice to MHV infection.
• These findings highlight the role of host immune status in MHV pathogenesis.