Why serology just is not enough: Strategic parvovirus risk assessment using a novel qPCR assay

Health monitoring of laboratory rodents not only improves animal health but also enhances the validity of animal experiments. In particular, infections of laboratory animals with murine parvoviruses influence biomedical research data. Despite strict barrier housing, prevalence remains high in animal facilities, leading to increased risk of parvovirus introduction after the import of contaminated mice. Unfortunately, hygienic rederivation can be challenging, since gametes often contain residual virus material. Consequently, the process has to be closely monitored with highly sensitive diagnostic methods to verify parvovirus decontamination of the rederived progeny. However, diagnostic sensitivity of traditional methods is often low and requires testing of large animal cohorts. Therefore, we aimed to develop a powerful quantitative real-time polymerase chain reaction (qPCR) assay for the fast and reliable detection of murine parvoviruses in different sample materials. We validated the assay within an infection experiment and systematically analysed various animal-derived and environmental sample materials. We further developed a strategic risk assessment procedure for parvovirus monitoring after embryo transfer. Our novel qPCR assay reliably detected parvovirus DNA in a broad variety of sample materials, with environmental samples dominating in the acute phase of infection, whereas animal-derived samples were more suitable to detect low virus loads in the chronic phase. Here, the assay served as a highly sensitive screening method for parvovirus contamination in mouse colonies, requiring significantly lower sample sizes than traditional methods like conventional PCR and serology. Thus, the use of our novel qPCR assay substantially improves parvovirus diagnostics, enhancing research validity according to the 6Rs.