Studies on Combined Infection with Low Pathogenic Avian Influenza (H9N2) and Newcastle Disease Genotype VII in Chickens

Abstract

ABSTRACT Co-infections of Newcastle disease (ND) and avian influenza (AI) were the major viruses causing high mortality and high economic losses. In this study 300 samples were collected from 50 chickens flocks suffering from respiratory symptoms , sever drop in egg production and mortalities from December,2013 to December, 2014. RT-PCR was performed to detect the M protein of H9 gene of avian influenza and F gene of velogenic NDV (vNDV) coinfections.

H9 PCR results were 20 and 34 in coloacal and pharyngeal swabs with total percentage of 6.7 % and 11.3%; respectively. The H9 sequences showed low pathogenic RSSR/GLF motif. The phylogenetic tree showed that H9 sequences belong to the G1 lineage which clustered with 2015 -2016 Egyptian H9N2. Partial sequences of the Fusion gene revealed that the isolated NDV isolates belong to class II genotype VIIj. The cleavage site of the F protein showed the presence of a polybasic amino acid motif ( ) suggesting that our two isolates were vNDV strain. Out of molecular identified H9 (1 isolate) and NDV Genotype VII (2 isolates) selected from were named AI/CHICKEN/EGYPT/48Ob/NRC-CU/2014(H9) , NDV/CHICKEN/EGYPT/48Ob/NRCCU/2014 ,

and NDV/CHICKEN/EGYPT/66Oc/NRC-CU/2014 , and nucleotide sequences were submitted to GenBank and given accession numbers MG966504, MG966505, and MG966506; respectively. 112 117 RRQKRF