RT-PCR Assay for Detection of Enterotropic Strains of Mouse Hepatitis Virus in Faecal

Background: Mouse Hepatitis Virus (MHV) is one of the most important and common viral infections of laboratory mice, due to its highly contagious and subclinical nature, posing threat to the research outcomes. Periodic screening of laboratory mice for MHV is mandatory. Hence, this study was intended to develop sensitive faecal based RT-PCR assays to detect active infection of enterotropic MHV in laboratory mice. Methods: Primers targeting N-gene of MHV were selected and their sensitivity was analysed in tenfold serially diluted gene template in the presence of negative mouse faecal cDNA. Thirty-six weaned mice at the age of 6 to 18 weeks were randomly selected at different periods and the blood and faecal sample were collected for serology and RT-PCR assay respectively. RT-PCR assay in colon samples was carried out for comparison. Result: PCR assay of MHV detected as low as 4 fg of plasmid DNA. Seroprevalence of MHV is very high than the prevalence by RTPCR assay showing its retrospective nature and also seroprevalence includes both enterotropic and polytropic strain. RT-PCR results in faecal samples are analogous with that of the colon samples, showing the reliability of antemortem testing of mice for enterotropic strain of MHV.