الفهرس 
AbstractOnly 14 pages are availabe for public view
 |  | from | 151 |  |  |
| | | from | 151 | | |
Abstract
Avian influenza has socio-economic importance all over the world. Emerging of Highly Pathogenic Avian influenza (H5N1) in Egypt caused severe losses due to high mortality and or depopulation of infected poultry farms. The aims of this work is to determine the difference and patterns of changes in Hem agglutination cleavage site(HACS )in Egyptian isolates from 2006 till February 2010 by Sequencing of 300 pb of the hemagglutinin (HA) gene of avian influenza (AI) H5N1 isolates. Forty two isolates were examined by real-time RT-PCR and the obtained results revealed that all isolates were positive for H5 gene. The same isolates have been examined by conventional RT-PCR for H5 Gene and exhibited the same findings. The 300bp fragment of the PCR product has been subjected to sequencing procedures. The HACS pattern in 2009 showed the most abundant number of changes. Phylogenetic analysis for both the amino acids and nucleotide sequences of the HACS and its flanking region indicates grouping of Egyptian isolates into separate groups. This study highlights the importance of recording the changes in HACS and links all these variations with other phenotypic characters of the circulating viruses in the Egyptian field Further studies are needed to clarify the impact of these mutations upon virus pathogencity and infectivity.