A High Resolution Melting (HRM) analysis to differentiate VG/GA Avinew strain from virulent Newcastle Disease virus strains and pathotypes

Seetha Jaganathan, Ooi Peck Toung, Phang Lai Yee, Zeenathul Nazariah Binti Allaudin, Tuam See Mun, Yip Lai Siong, Choo Pow Yoon, Lim Ban Keong, Stephane Lemiere & Jean-Christophe Audonnet


Despite intensive vaccination programs, Newcastle disease virus (NDV) remains a constant threat to commercial poultry farms in Malaysia. Traditionally, NDV pathotypes (velogenic/mesogenic/lentogenic) are most commonly distinguished by sequencing and amino acid sequence analysis. However, with the rapid development of real-time PCR methods in recent years, there has been significant expansion to molecular diagnostics of various infectious agents through various novel methodologies [1]. Most importantly, a major concern in disease diagnostics is whether the disease outbreak is caused by a virulent field virus or due to a failed vaccination program. The present study describes a High Resolution Melting (HRM) curve analysis which distinguishes: 1) NDV pathotypes (lentogenic/mesogenic/velogenic) and 2) differentiates live vaccine strains (e.g VG/GA Avinew strain) from virulent ND field virus (Differentiation of Infected versus Vaccinated (DIVA) assay). A primer spanning the F0 cleavage site of the fusion (F) protein gene was used to investigate its usefulness for characterizing the pathotypes present in NDV and investigating the DIVA assay.