Kinetics of Transmission, Infectivity, and Genome Stability of Two Novel Mouse Norovirus Isolates in Breeding Mice

• Published in: Comparative medicine 2009-02, Vol.59 (1), p.27-36
• Main Authors: Kelmenson, Jennifer A, Pomerleau, Darcy P, Griffey, Stephen, Zhang, Weidong, Karolak, Michele J, Fahey, James R
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Viral - analysis; antibody formation; Caliciviridae Infections - diagnosis; Caliciviridae Infections - transmission; Caliciviridae Infections - veterinary; disease transmission; Feces - virology; Female; genetic stability; genome; histopathology; Immunocompromised Host; infection; Infectious Disease Transmission, Vertical - veterinary; laboratory animals; Male; Mice; Mice, SCID; Mouse Models; mutation; Norovirus; Norovirus - isolation & purification; Norovirus - pathogenicity; Norovirus - physiology; Orf2 gene; pathogenicity; Pregnancy; RNA, Viral - analysis; Rodent Diseases - blood; Rodent Diseases - transmission; Rodent Diseases - virology; sequence homology; Serologic Tests - veterinary; Species Specificity; strain differences; Time Factors; tissue distribution; viral diseases of animals and humans; virus shedding; Virus Shedding - physiology
• ISSN: 1532-0820; 2769-819X

Murine noroviruses are a recently discovered group of viruses found within mouse research colonies in many animal facilities worldwide. In this study, we used 2 novel mouse norovirus (MNV) wildtype isolates to examine the kinetics of transmission and tissue distribution in breeding units of NOD.CB17-Prkdc(scid)/J and backcrossed NOD.CB17-Prkdc(scid)/J x NOD/ShiLtJ (N1) mice. Viral shedding in feces and dissemination to tissues of infected offspring mice were monitored by RT-PCR over a 6-wk period postpartum. Histologic sections of tissues from mice exposed to MNV were examined for lesions and their sera monitored for the presence of antibodies to MNV. Viruses shed in feces of parental and offspring mice were compared for sequence homology of the Orf2 gene. Studies showed that the wildtype viruses MNV5 and MNV6 behaved differently in terms of the kinetics of transmission and distribution to tissues of offspring mice. For MNV5, virus transmission from parents to offspring was not seen before 3 wk after birth, and neither isolate was transmitted between cages of infected and control mice. Susceptibility to infection was statistically different between the 2 mouse strains used in the study. Both immunodeficient NOD. CB17-Prkdc(scid)/J mice and NOD. CB17-Prkdc(scid)/J x NOD/ShiLtJ offspring capable of mounting an immune response shed virus in their feces throughout the 6-wk study period, but no gross or histologic lesions were present in infected tissues. Progeny viruses isolated from the feces of infected offspring showed numerous mutations in the Orf2 gene for MNV5 but not MNV6. These results confirm previous studies demonstrating that the biology of MNV in mice varies substantially with each virus isolate and mouse strain infected.