الفهرس | Only 14 pages are availabe for public view |
Abstract A total of 50 layer flocks of different breeds and ages were collected from different localities within Sharkia governorate during 2017 -2019 suspected to be infected with avian influenza virus (AIV). Respiratory signs and/or decrease in egg production were observed among the examined flocks. The isolation and identification of AI viruses were carried out on ECE using HA test and real time PCR as well as partial sequence analysis of NA genes. Thirty five (70%) isolates were hemagglutinating positive. The 35 hemagglutinating virus isolates were identified as 16 (45. 71%) out of 35 were positive for AIVs, out of 16 positive AIVs 4 flocks (25%) were H5 subtype positive, 9 flocks (56.25%) were H9 subtype positive and 3 (18.75%) mixed flocks with H5 and H9 as well as 26 (74.28%) out of 35 were positive NDV by using real time PCR. Three H9N2 viruses, two H5N8 viruses and 3 NDV were partially sequenced. Sequence analysis revealed that the HA protein of 3 H9 isolates harbor a proline-alanine-arginine-serine- serine-arginine (PARSSR/G) motif, which is characteristic for low pathogenicity in chickens. The three isolates showed that they share 99-100% homology for HA and NA genes at amino acid level. The percent of identity of 3 H9 isolates obtained in this study with parent strain (A/Quail/Egypt/113413v/2011) was 95.6-96.2%. |