Prevalence of Mouse Norovirus in Experimental Mice in Beijing

Abstract

ObjectiveTo investigate the infection of mouse norovirus (MNV) in experimental mice raised under natural conditions from 19 biological companies in Beijing.MethodsThe mice used in this study were randomly selected from mice produced by 19 companies, and 14 mice of each strain and batch were combined into one cage, totaling 1 396 cages of 19 544 mice. The fecal samples from BALB/c, C57BL/6, ICR, KM, and BALB/c-nude mice were collected. TaqMan probe fluorescence quantitative PCR method was used to detect MNV infection of mice with MNV-1 primer, and whether the mice were infected with MNV was determined according to cycle threshold (Ct value). The chi-square test was used to analyze the difference of positive rate among the fecal samples from the five types of mice. The Ct values of the positive samples were statistically described; the non-parametric test was used to analyze the differences in Ct values among the five types of mice. Results A total of 1 396 fecal samples were collected. The positive rates of fecal MNV detection in BALB/c, C57BL/6, ICR, KM, and BALB/c-nude mice were 17.65%, 39.33%, 10.57%, 18.32% and 27.4%, respectively. According to the chi-square test results, the positive rate of fecal in C57BL/6 mice was higher than that in BALB/c, ICR, and KM mice (all P<0.05), and the positive rate of BALB/c-nude mice was higher than that in ICR and BALB/c mice (P<0.001, P＜0.05) . The viral load of BALB/c-nude or C57BL/6 mice was generally greater than that of KM mice (P<0.05).ConclusionMNV-1 primers can be applied to the detection of MNV infection in mice. The positive rate of MNV in five types of experimental mice in Beijing ranges from 10% to 40%, among which C57BL/6 mice and BALB/c-nude mice have higher positive rates of MNV than the others.

Keywords

• mouse norovirus
• taqman probe
• fluorescence quantitative pcr
• natural infection