Natural infection of murine norovirus in conventional and specific pathogen-free laboratory mice

Takeo Ohsugi,Satomi Kawabe,Makoto Wakamiya,Kumi Matsuura,Naoko Nakamura,Toru Urano,Saki Morikawa,Jerald M Kumar

doi:10.3389/fmicb.2013.00012

Abstract

Noroviruses cause most cases of acute viral gastroenteritis worldwide. The lack of a cell culture infection model for human norovirus necessitates the use of molecular methods and/or viral surrogate models amenable to cell culture to predict norovirus inactivation. Murine norovirus (MNV) may be used to construct a small animal model for studying the biology and pathogenesis of noroviruses because MNV is the only norovirus that replicates in cell culture and a small animal model. However, recent studies have shown that natural MNV infection is widespread in laboratory mouse colonies. We investigated MNV infection in both conventional and specific pathogen-free (SPF) genetically modified mice from Japan and the US, and commercial mice from several animal breeders in Japan, using serological and molecular techniques. MNV antibodies were detected in 67.3% of conventional mice and 39.1% of SPF mice from Japan and 62.5% of conventional mice from the US. MNV antibodies were also found in 20% of commercial SPF C57BL/6 mice from one of three breeders. Partial gene amplification of fecal isolates from infected animals showed that the isolates were homologous to reported MNV sequences. These results suggest that both conventional and SPF laboratory mice, including commercial mice, are widely infected with MNV, which might require considerable attention as an animal model of human disease.

Highlights

Human noroviruses are the major cause of non-bacterial epidemic gastroenteritis worldwide (Patel et al, 2009)
In this study, we analyzed Murine norovirus (MNV) infection in mice derived from animal facilities in Japan, the US, and three breeders (Japan) using serological and molecular techniques
We show that MNV infection is widespread among both conventional and specific pathogen-free (SPF) mice in Japan, as well as commercial SPF mice

Summary

Introduction

Human noroviruses are the major cause of non-bacterial epidemic gastroenteritis worldwide (Patel et al, 2009). MNV is the only norovirus that replicates in cell culture and in a small animal model, though several studies have reported norovirus infection in humans, cattle, swine, dogs, and mice (Wobus et al, 2006; Patel et al, 2009). Natural MNV infection is prevalent in animal facilities around the world (Hsu et al, 2005; Perdue et al, 2007; Pritchett-Corning et al, 2009) These infections might influence the results of a mouse model for studying the biology and pathogenesis of noroviruses, and those of other biological studies (Lencioni et al, 2008; Cadwell et al, 2010). Most researchers in Japan think that MNV infection is absent among SPF mice facilities

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Results

Conclusion