Molecular characterization of newcastle disease virus genotype VIId in Avian influenza H5N1 infected broiler flock in Egypt

Hussein, H. A. and Emara, M. M. and Rohaim, M. A. (2014) Molecular characterization of newcastle disease virus genotype VIId in Avian influenza H5N1 infected broiler flock in Egypt. International Journal of Virology, 10 (1). pp. 46-54. ISSN 1816-4900

Abstract

In the early months of 2011, several devastating Newcastle disease outbreaks occurred in Egypt affecting commercial poultry. Both vaccinated and unvaccinated flocks were affected. In the present study, we characterized field isolate of NDV from a broiler flock coinfected with Avian influenza H5N1 showing characteristic clinical signs, post mortem gross lesions and was positive to A.I H5N1 and NDV by RT-PCR. The fusion protein gene of the Newcastle Disease Virus (NDV) isolate was partially amplified by RT-PCR, directly sequenced. The obtained sequence was submitted to GeneBank with the accession No. JX885868 (NDV/chicken/VRLCU138/Egypt/2012). Sequence was aligned and compared with a representative NDV isolates of different genotypes using NCBI BLAST. The F protein cleavage site sequence is a well-characterized determinant of NDV pathogenicity in chickens. The NDV isolate was found to have the motif 112RRQKRF117 which is indicative of the velogenic nature of this NDV isolate. Phylogenetic analysis revealed that then isolated NDV is belonging to subgenotype VIId and in close range to other Chinese VIId NDV isolates based on the high nucleotide similarity between them which indicate that genotype VIId is circulating between chicken flocks. This study reports the characterization of Newcastle Disease Virus genotype VIId in broiler chickens coinfected with Avian influenza H5N1 virus.