Epidemiological, Phylogenetic Analysis and Pathogenicity of Newcastle Disease Virus Circulating in Poultry Farms, Egypt during 2015-2018
Epidemiological, Phylogenetic Analysis and Pathogenicity of Newcastle Disease Virus Circulating in Poultry Farms, Egypt during 2015-2018
Ali Mahmoud Zanaty, Naglaa Mohammed Hagag, Neveen Rabie, Mahmoud Saied, Karim Selim, Saad A. Mousa, Azhar Gaber Shalaby, Abdel-Sattar Arafa and Mohamed Khalifa Hassan
ABSTRACT
Newcastle disease virus (NDV) is a highly contagious disease in poultry, also considered as a major threat for commercial and traditional poultry industry in Egypt, even in vaccinated flocks. A total of 8121 different samples (organs and swabs) that represented 588 NDV suspected flocks were collected from poultry farms showing respiratory manifestation and/or drop in egg production during 2015-2018. Out of 588 NDV outbreaks 95 flocks were confirmed positive NDV by rRT-PCR using genotyping primers, with a prevalence rate of 16.2%. NDV outbreaks were recorded in 16 governorates, from total of18 investigated governorates and the recorded geo-prevalence of 89 %. Twenty-five samples were selected for further sequencing for the partial fusion protein. Phylogenetic analysis revealed that 20 samples are genotyped as very virulent NDVclass II of genotype VIIb, 4 samples were of high identity (94%-100%) with NDV class II of genotype II (vaccine strain) and 1 sample was phylogenetically related to NDV class II of genotype I with 98% identity. Furthermore, the intracerebral pathogenicity index (ICPI) for selected 5 virulent viruses reveals velogenic features with high pathogenicity index (1.60 to 1.74).
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