A phosphoprotein gene RT-qPCR assay to detect all lineages peste des petits ruminants virus

Jiao Xu^1*Yonggang Zhao¹Huicong Li²Qinghua Wang¹Jiarong Yu¹Yingli Wang¹Jingyue Bao¹Zhiliang Wang¹

• ¹China Animal Health and Epidemiology Center, Qingdao, China
• ²Qingdao Agricultural University, Qingdao, China

Peste des petits ruminants (PPR) is a highly contagious disease that is caused by peste des petits ruminants virus (PPRV). PPRV is classified into four lineages based on the nucleocapsid (N) or fusion (F) genes. We established a TaqMan quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) assay using a pair of primers and a probe based on the phosphoprotein (P) gene. The method was assessed for its sensitivity, specificity, and repeatability, in the detection of field samples, and was compared with the standard detection method. The developed method could detect all lineages of PPRV, with a sensitivity of 4 copies/μL for lineage II to lineage IV, and 40 copies/μL for lineage I. The results of the specificity test indicated that only the different lineages of PPRV could be detected using the developed method and no cross-reaction with other viruses was observed. The coefficients of variation of the intra-assay repeatability and inter-assay repeatability tests were all less than 1.50%, which demonstrated good repeatability. The detection of field samples, including PPRV-positive and PPRV-negative samples, indicated that all samples could be detected correctly, which showed a high coincidence with the standard detection method. The developed method could detect PPRV with a lower cycle threshold value compared with that of the previously established N gene-based method, especially for weakly positive samples. This RT-qPCR assay provides a valuable tool to facilitate targeted surveillance and rapid differential diagnosis in regions with active circulation of PPRV, enabling timely epidemiological investigations and strain-specific identification.