A diagnostic method based on MGB probes for rapid detection and simultaneous differentiation between virulent and vaccine strains of avian paramyxovirus type 1

Newcastle disease virus (NDV), also designated avian paramyxovirus type 1 (APMV-1), is a serious pathogen of poultry, causing highly contagious Newcastle disease (ND), with high morbidity or mortality, depending on the strain. Accordingly, rapid and reliable detection of APMV-1 and differentiation between vaccine and virulent strains is of crucial importance for ND diagnosis and plays an important role in effective control of the disease.In this study, two real-time reverse transcription polymerase chain reaction (real-time RT-PCR) assays using minor groove-binding (MGB) probes were developed for broad range detection and simultaneous pathotyping of APMV-1. The two assays were evaluated for their ability to detect in allantoic fluids viral RNA of all known APMV-1 lineages. Additionally, the applicability of the developed assays was assessed by the detection and pathotype prediction of APMV-1 in swabs and organs. The assays demonstrated high analytical specificity, sensitivity and good reproducibility, with coefficients of variation ranging from 0.2% to 3.9% and from 0.6% to 7.2% for intra-assay and inter-assay variability, respectively. The results indicated the suitability of both assays as a complementary method for rapid screening and typing of APMV-1.