Development and partial validation of a TaqMan quantitative PCR assay to detect Cervidpoxvirus

BACKGROUND: An emerging disease known as mule deerpox virus (Cervidpoxvirus muledeerpox) (DPV) has spread across North America in both wild and captive cervid populations. While little is known about its prevalence in wild cervids, research in domestic populations indicates a high mortality associated with this pathogen, particularly in fawns. Most recently, a new Cervidpoxvirus has been reported in semi-domestic populations of reindeer in Sweden and Norway, expanding its geographical range internationally. Currently, there is no standard protocol to detect this virus, and the increasing range of this pathogen highlights the importance of a standard validated diagnostic test. RESULTS: In this study, we developed and partially-validated a TaqMan quantitative PCR assay to detect Cervidpoxvirus based on the major capsid protein using the World Organization for Animal Health's diagnostic assay guidelines. Aligning the three available whole genomes of DPV from GenBank W-848-83 (GenBank: NC_006966.1); W-1170-84 (GenBank: AY689437.1); MDPV-F (GenBank: MF966153), showed that the major capsid protein gene was highly conserved (> 99%) and primers and probe were designed to amplify a 83 bp region of this gene with 100% agreement. Analytical performance estimated that the assay was exclusive for DPV and highly sensitive (limit of detection ≥ 10 DNA copies), while diagnostic performance found that the assay was 100 times more sensitive than a standard conventional PCR assay. CONCLUSION: With this assay, detection of Cervidpoxvirus will be faster and more efficient than current methods, allowing both researchers and veterinarians to diagnose and prevent the further spread of this disease.