Molecular detection of novel astroviruses in wild and laboratory mice.

Pooled fecal specimens collected from striped field mice (Apodemus agrarius), yellow-necked mice (Apodemus flavicollis), and bank voles (Myodes glareolus) and individual stool samples collected from laboratory mice were tested for the presence of picornaviruses and astroviruses. Picornavirus RNA was detected only in one striped field mouse sample pool, while astrovirus RNA was detected in two yellow-necked mouse sample pools and in six of the 121 laboratory mouse samples. In a 234-amino acid (aa) fragment of the viral RNA dependent RNA polymerase (RdRp), the wild mouse picornavirus revealed the closest homology to the canyon mouse (Peromyscus crinitus) (93 % aa) and canine kobuviruses (92 % aa) and to Aichi virus (88 % aa). The two astroviruses detected in the yellow-necked mouse samples shared 77 % aa homology with each other in the partial (125 aa) RdRp region, 61-62 % aa homology with rat astroviruses and only 54-58 % aa homology with the house mouse (Mus musculus) astrovirus strain USA/2008/M52. The six laboratory mouse astroviruses displayed 97-100 % aa homology to each other, and shared 71-77 % aa homology with the yellow-necked mouse astroviruses, 58-59 % aa homology with rat astroviruses and 55-56 % aa homology with strain USA/2008/M52. The sequence of a 3,263 bp genome segment including the partial ORF1b (RdRp), complete ORF2 (capsid precursor), and 3' NTR of a research mouse astrovirus strain (TF18LM) was determined. The full-length ORF2 showed low identities (17-34 % aa) with other members of the Mamastrovirus genus and only 17 % aa homology with the house mouse astrovirus strain USA/2008/M52, indicating that AstVs described in this study represent a novel Mamastrovirus species. The relevance of astrovirus infection and its effect on biomedical research conducted in mice needs to be investigated.