PHYLOGENETIC CHARACTERIZATION OF VELOGENIC NEWCASTLE DISEASE VIRUSES ISOLATED FROM FIELD OUTBREAKS AMONG VACCINATED BROILER CHICKENS IN UPPER EGYPT

Serag Eldeen Sultan ,Nabila Osman ,Ahmed I Ahmed ,Roshita Ibrahim ,Mahmoud Sabra

doi:10.21608/avmj.2015.170195

Serag Eldeen Sultan , Nabila Osman + Show 3 more

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https://doi.org/10.21608/avmj.2015.170195

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Abstract

A total of 42 Newcastle disease virus (NDV) strains were isolated from clinical samples obtained from chickens during field outbreaks among vaccinated broiler chicken's farms in the Upper Egypt in 2011 - 2012. The samples were inoculated into embrayonated chicken eggs and the positive samples for NDV were detected by hemagglutinination (HA) and confirmed by hemagglutination inhibition (HI) tests and reverse transcriptation polymerase chain reaction (RT-PCR). The pathogenicity of the isolates was estimated biologically by intracerebral pathogenicity index (ICPI) test and genetically by sequencing the partial fusion (F) genes. The ICPI indicated that 40 isolates were > 1.5, which characterized velogenic strains, the remaining was mesogenic (ICPI = 1.4). The sequencing analysis of the nucleotides and deduced amino acids, 8 isolates representing the isolates from different localities, revealed that these isolates possess the amino acids motif 112-R-R-Q-K- R-F-117 of the velogenic nature and a diversity of 19 –22 and 19-21 % in nucleotides and amino acids, respectively, from vaccine strains (LaSota, B1, Ulster/67 and I-2) and Texas/GB. Interesting, that these isolates clustered into two subgroups related to the isolates from Jordan, Israel (2011) and China but were distant from vaccine, Egyptian (2005, 2006 and 2010), Sudan, Saudi Arabia and Israel (2003) strains by phylogenetic analysis. In conclusion, a velogenic NDV prove to circulate among chickens in southern of Egypt although intensive vaccination programs were conducted. These isolates were genetically away from the vaccine strains and virulent to chickens. The necessity needs to continuously monitor the virus and evaluate the vaccination programs efficiency.

Highlights

Newcastle disease (ND) virus (NDV), a member epidemiological studies of NDV have been carried of the avian paramyxovirus serotype 1 (APMV-1), out worldwide using molecular based methods belongs to the genus Avulavirus within the (Aldous et al, 2003; Abolnik et al, 2004; Lee et al, Paramyxoviridae family and is the causative agent of 2004; Liu et al, 2007; Bogoyavlenskiy et al, 2009, ND (Mayo, 2002)
Eight out of the 42 NDV positive isolates were selected from different localities (5/28 Sohag, 2/12 Qena and 1/2 Luxor) based on the number of isolates obtained from this area, at different time (2011 (4/42) and (4/42) 2012), age, flock capacity, clinical signs, postmortem examination (PM) lesions and mortality rates (Tables 1 and 2)
Comparative analysis of nucleotide and deduced amino acid sequences of the partial F genes The nucleotide similarities of the 420 nucleotides fragment, between the start codon and the cleavage site of the F gene, and predicted amino acid sequences of 139 residues of the 8 NDV isolates were compared with the corresponding sequences of the LaSota, the frequently used vaccine strain in Egypt, Texas/GB and Egyptian isolates (2006 and 2012) from northern Egypt (Table 3)

Summary

Introduction

ND virus (NDV), a member epidemiological studies of NDV have been carried of the avian paramyxovirus serotype 1 (APMV-1), out worldwide using molecular based methods belongs to the genus Avulavirus within the (Aldous et al, 2003; Abolnik et al, 2004; Lee et al., Paramyxoviridae family and is the causative agent of 2004; Liu et al, 2007; Bogoyavlenskiy et al, 2009, ND (Mayo, 2002). It is enveloped, negative-sense, Umali et al, 2013). The obtained sequenced data was compared with NDV strains isolated from the Lower Egypt, Middle East, Israel and China as well as vaccine strains and a novel NDV strain Texas/GB isolated in 1948 from chicken in USA

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