title: Genetic analysis of Newcastle disease virus from Punjab, Pakistan.
abstract: The strains of Newcastle disease virus (NDV) were isolated from five suspected outbreaks of ND in broiler (n = 3) and layers (n = 2) poultry farms. The egg-isolated viruses were subjected to biological and genetic characterization. Based on the biological characterization, isolates showed haemagglutination titer ≥log 2(7), mean death time <55 h, intracerebral pathogenecity index ≤1.8, and egg lethal dose 50 from 10(-7.15) to 10(-9.31)/1 ml. Genetic characterization of the fusion (F) gene revealed that the isolates clustered with NDV strains of genotype VII (VIIf) within class II, which remained predominant genotype in the domestic poultry of Asia. The deduced amino acid sequence of the isolates confirmed virulent motif (112)RRQKRF(117) at the F protein cleavage site. A bioinformatics and pairwise comparison approach was applied to estimate the synonymous and non-synonymous substitution rates (dN/dS) and selective evolutionary pressure for the F protein. The dN/dS calculated for genotype VII indicate purifying selection, which resulted in a low evolution rate in F gene. The F protein shows a strong negative pressure throughout the length of the protein and no recombination event was determined. Collectively, the results suggest that very similar virulent strains of NDV are involved during current wave of disease outbreak throughout the country. From these results, in conjunction with our recent reports of NDV from Pakistan, it is possible to conclude that emergence of novel group may require revisiting the diagnostics and vaccine control strategies.
authors.affiliation: University Diagnostic Laboratory, University of Veterinary and Animal Sciences, Lahore 54600, Pakistan.
authors.forename: Muhammad Zubair
authors.initials: MZ
authors.lastname: Shabbir
authors.forename: Muhammad
authors.initials: M
authors.lastname: Abbas
authors.forename: Tahir
authors.initials: T
authors.lastname: Yaqub
authors.forename: Nadia
authors.initials: N
authors.lastname: Mukhtar
authors.forename: Atta
authors.initials: A
authors.lastname: Subhani
authors.forename: Hasham
authors.initials: H
authors.lastname: Habib
authors.forename: Muhammad Umar
authors.initials: MU
authors.lastname: Sohail
authors.forename: Muhammad
authors.initials: M
authors.lastname: Munir
mesh_terms: D000818:Animals; D002645:Chickens; D008969:Molecular Sequence Data; D009521:Newcastle Disease / Q000453:epidemiology / Q000821:virology*; D009522:Newcastle disease virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D010154:Pakistan / Q000453:epidemiology; D010802:Phylogeny; D011201:Poultry Diseases / Q000453:epidemiology / Q000821:virology*; D014760:Viral Fusion Proteins / Q000235:genetics
chemical_list: D014760:Viral Fusion Proteins