Development of a duplex real-time RT-qPCR assay to monitor genome replication, gene expression and gene insert stability during in vivo replication of a prototype live attenuated canine distemper virus vector encoding SIV gag.

•The duplex assay monitored replication, tissue distribution, and mRNA expression.•The duplex assay monitored insert genetic stability during in vivo replication.•Primary site of CDV replication in ferrets was abdominal cavity lymphoid tissue.•CDV gRNA or mRNA was undetectable in brain tissue.•Specific primers were used in the RT step to distinguish gRNA from mRNA.