Molecular characterization and phylogenetic analysis of newcastle disease virus isolated from clinical cases of newcastle disease in commercial layer farms in the Philippines

Issue Date

1-2017

Abstract

Newcastle Disease (ND) is an economically devastating disease of poultry. At present, limited data are available regarding the molecular characteristics of Newcastle disease virus (NDV) from the Philippines. Clinical and molecular characterizations were performed on five clinical cases of ND in vaccinated commercial layer farms from four provinces in the Philippines, namely Bulacan, Pampanga, Zamboanga del Sur and Davao Del Sur. Clinical signs observed on affected flocks were conjunctivitis, gasping, tracheal rales, facial swelling, lethargy, greenish diarrhea, torticollis and paralysis. Disease onset ranged from 21 to 124 days with mortality rates of 15 to 61%. Gross morphological lesions identified were presence of serous exudates in the infraorbital sinuses, hemorrhagic trachea, inflamed spleen, liver and kidneys and petechial hemorrhages in the proventriculus and cecal tonsils. Nucleotide sequencing showed that all field strains were velogenic with FO proteolytic cleavage site of 112RRRKRz.ast;F117 and 112RRQKRz.ast;F117 patterns. Phylogenetic analysis showed that all field NDV strains belong to class II genotype VII, subgenotypes Vila, Vllh and Vili. Evolutionary divergence showed that the field NDV strains were closely related (up to 99% similarity) to the newly identified subgenotypes of virulent NDVs currently emerging in Southeast Asia and the Middle East.

Source or Periodical Title

Philippine Journal of Veterinary Medicine

ISSN

0031-7705

Volume

54

Issue

1

Page

17-26

Document Type

Article

Physical Description

illustrations, tables

Language

English

Subject

Genotype VII, Layers, Newcastle disease virus, Philippines, Phylogenetic analysis

Digital Copy

yes

Link to Full Text

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