A multiplex reverse transcription-nested polymerase chain reaction for detection and differentiation of wild-type and vaccine strains of canine distemper virus

Si, Wei; Zhou, Shun; Wang, Zhao; Cui, Shang-jin

Caideron et al [16] performed an extensive phylogenetic and molecular evolution analysis on complete sequences of all CDV genes to assess the role of selection and recombination in shaping viral genetic diversity and driving the emergence of CDV in non-dog hosts. They tested the specific hypothesis that molecular adaptation at known receptor-binding sites of the haemagglutinin gene is associated with independent instances of the spread of CDV to novel non-dog hosts in the wild. The selected two samples isolated from dogs were classified into a branch which belongs to the wild-type strain, but constituting a genotype different from that of CDV vaccine strains, as revealed by phylogenetic analysis based on the sequences of the H gene region, which is believed to be the most reliable classification and genetic typing. RT-nPCR was used to detect the 51 field samples in Shandong provinces; 36 of the field samples were CDV-positive, among which 20 were wild-type strain, 16 were vaccine strain, and 4 were co-infected by wild-type and vaccine strains. In summary, the multiplex RT-nPCR developed in this study is a highly specific and sensitive assay for the rapid detection and differentiation of wildtype and vaccine strains of CDV.