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Abstract
A total of 15 broiler chicken flocks belonging to Desouk and Qallin (Kafr el-Sheikh Gov.) as well as to Bassioun (Gharbia Gov.) exhibited rapid increase in mortality rate and respiratory manifestation were thoroughly investigated during the period from December 2013 to January 2015. Rapid field detection of AIV by immuno- chromatography tests revealed detection of AIV antigen in one (6.67 %) broiler chicken flock. Twenty one tissue pool samples collected from the broiler chicken flocks as well as 244 swabs and one brain tissue pool from 127 free living birds- in the vicinity and inside the affected broiler chicken farms- were subjected for isolation and molecular characterization of NDV and AIV subtypes (H5 and H9). In addition, 75 and 60 samples (pooled; liver, heart and spleen) from broiler chickens and free living birds respectively subjected to isolation and characterization of E. coli by using selective media, serotyping, in vitro and in vivo virulence assay. Nineteen (90.48 %) and 2 (9.52 %) out of 21 samples collected from broiler chicken flocks showed positive isolation for NDV and AIV H5 respectively, whereas 25 (10.2 %) and one (0.41%) out of 245 samples from free living birds showed positive isolation for NDV and AIV H5 respectively and no positive results could be obtained for AIV H9N2 from all samples. Molecular characterization by sequencing of F gen fragment and phylogenetic analysis of the selected 13 NDV isolates, revealed two isolates from broiler chicken flocks and 9 isolates from free living birds had possessed the same velogenic genotype motif of ¹¹²R-R-Q-K-R-F¹¹⁷, in addition to clustering with published class II genotype VII sub genotype d NDVs and closely related to Israel and China isolates, whereas one isolate from broiler chicken flocks had possessed the lentogenic genotype motif of ¹¹²G-R-Q-G-R-L¹¹⁷, in addition to clustering with published class II genotype II NDVs. Molecular characterization of pigeon NDV isolate showed velogenic genotype motif ¹¹²K-R-Q-K-R-F¹¹⁷ and clustered with published class II genotype VI. Molecular characterization of two selected AIV H5 isolates (cattle egrets and broiler chickens) by sequencing of HA gen fragment and phylogenetic analysis revealed clustering the isolates in the same subclade 2.2.1/ C