Newcastle Disease in Backyard Poultry Rearing in the Northeastern States of India: Challenges and Control Strategies

Newcastle disease (ND) or Ranikhet disease is an avian viral disease, highly contagious in nature affecting many domestic avian species and wild birds.The disease is caused by infections with virulent avian avulavirus 1, commonly known as Newcastle disease virus (NDV) and designated as avian paramyxovirus-1 (APMV-1).It causes high morbidity and mortality in naïve, poorly vaccinated (1) or non-vaccinated birds, while the production performance in vaccinated birds is affected too when infected with virulent strains. VIRUS AND HOST RANGEThe different parts of the world reported different genotypes of APMV-1 in different avian species.Though all NDVs are the members of AMPV-1.NDV has been classified into class I and class II viruses based on their genetic characteristics.The class I viruses have been mostly isolated from wild birds and are generally of low virulence and rarely found in poultry species.There is a wider genetic variability reported within class II viruses, and currently, there are 18 class II genotypes based on the whole genome or the variability of protein F (1, 2).An updated NDV classification and nomenclature system incorporate phylogenetic topology, genetic distances, branch support, and epidemiological independence (3).