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Updated: May 30, 2026
Reverse Genetics Mediated Recovery of Infectious Murine Norovirus
Published on: June 24, 2012
Eliminating murine norovirus by cross-fostering
Laurence U Buxbaum1, Pierina C DeRitis, Niansheng Chu
1Veterans Affairs Medical Center, and Division of Infectious Diseases, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA. buxbaum@mail.med.upenn.edu
Abstract:
Murine norovirus (MNV) is a newly discovered and extremely prevalent pathogen of laboratory mouse colonies. MNV causes severe disease in some immunocompromised mouse strains and can cause persistent infections even in immunocompetent mice. Despite the fact that immunocompetent mice are generally asymptomatic, the possibility that MNV infection might alter immune responses makes its eradication a potentially useful goal for many facilities. Initial attempts by others to use a strategy of testing and culling were unsuccessful, whereas complete depopulation and facility decontamination was successful. However, these measures may be impractical, and finding less drastic approaches seemed prudent. Based on a report that cross-fostering of pups from MNV-positive mothers to MNV-negative ones could be successful in experimental MNV infection, we undertook a comprehensive fostering program using Swiss Webster mothers, careful sanitary measures, and fecal PCR testing to eradicate the virus from a mouse colony recently infected with MNV. We successfully decontaminated 17 of 18 (94%) litters and managed to prevent spread when a new MNV-infected mouse strain entered quarantine at our facility. These results suggest that cross-fostering, when performed in a setting of excellent sanitary procedures, may be practical for the large number of mouse facilities in which MNV is endemic.
Insights
Murine norovirus (MNV) eradication can be achieved through cross-fostering. This method, combined with strict sanitary protocols and PCR testing, successfully decontaminated 94% of infected mouse litters.
Area of Science:
- Veterinary Virology
- Laboratory Animal Science
- Infectious Disease Control
Background:
- Murine norovirus (MNV) is a widespread pathogen in laboratory mouse colonies.
- MNV can cause severe disease in immunocompromised mice and persistent infections in immunocompetent mice.
- Eradicating MNV is crucial as it may alter immune responses, impacting research outcomes.
Purpose of the Study:
- To evaluate the efficacy of cross-fostering as a practical method for MNV eradication in a mouse colony.
- To assess the feasibility of preventing MNV spread within a facility using this approach.
Main Methods:
- A comprehensive cross-fostering program was implemented using Swiss Webster mothers.
- Strict sanitary measures and fecal PCR testing were employed throughout the process.
- The strategy was tested on a recently infected colony and during the introduction of a new infected strain into quarantine.
Main Results:
- Successful decontamination of 17 out of 18 (94%) infected litters was achieved.
- The spread of MNV was prevented when a new infected mouse strain was introduced into quarantine.
- The study demonstrated the effectiveness of the combined approach in controlling MNV.
Conclusions:
- Cross-fostering, when integrated with rigorous sanitary procedures and diagnostic testing, offers a practical and effective strategy for MNV eradication.
- This method presents a viable alternative to more drastic measures like depopulation for endemic MNV situations.
- The findings support the widespread application of this technique in mouse facilities managing MNV infections.
