Molecular characterization and phylogenetic analysis of Newcastle disease virus isolated from poultry in North Central States of Nigeria

Newcastle disease (ND) is a highly contagious viral disease constituting a continuous threat to the poultry industry worldwide. This study evaluated the genetic characteristics of Newcastle disease viruses (NDVs) obtained from backyard commercial poultry farms and live bird markets during active and passive surveillance in different regions of Plateau and Nasarawa States of Nigeria between 2009 and 2017. The partial fusion (F) gene coding sequence and cleavage site of five NDV isolates was determined. This was aligned and compared with sequences of representative NDV from the GenBank. Deduced amino acid sequence of the protein revealed that four isolates had virulent motifs (112RRQKRF117) while one had an avirulent motif (112GRQGRL117). One virulent strain was recovered from an apparently healthy duck. Phylogenetic analysis based on comparison with different classes of NDVs revealed that two isolates clustered with genotype XIVb NDVs, another two isolates clustered with genotype XVIIa while one isolate clustered with genotype II. The phylogenetic analysis revealed that the velogenic isolates clustered with published class II genotype XIVb and XVIIa closely related to isolates from Benin and Niger republic. This highlights the need for ND control programmes to place more stringent measures on cross-border trade of live bird and poultry products to prevent the introduction of new strains of NDV that would be more difficult to control.