Assessment of thermostability profile of mesogenic Newcastle disease virus (Genotype XIII) isolates from Assam, India.

Abstract

Newcastle disease (ND) is a devastating viral disease affecting poultry and has a substantial economic impact associated with high morbidity and mortality rates. Effective control measures rely on biosecurity measures and vaccination. However, use of phylogenetically divergent, thermolabile vaccines remains a major constraint for controlling ND outbreaks despite vaccination. To address the gap, the present study was undertaken to assess the thermostability profile of mesogenic (Genotype XIII) Newcastle disease virus (NDV) isolates with the aim of identifying heat-stable strains circulating in Assam, India. Five NDV isolates were assessed for thermostability by subjecting them to a range of temperatures at different time intervals. Among the isolates, AS/KM/18/32 exhibited the highest thermal stability, retaining HA (log) titer and infectivity (log EID) at 56 °C for 30 min, with a half-life of 19.99 min and an inactivation rate constant of -0.0348 min. In conclusion, mesogenic NDV (Genotype XIII) isolates circulating in Assam exhibit variable thermostability, warranting further studies on their biological pathogenicity and immunogenicity with a view to developing genotype-matched thermostable vaccine candidates.