الفهرس 
cover englishOnly 14 pages are availabe for public view
 |  | from | 220 |  |  |
| | | from | 220 | | |
Abstract
Thirty-one broiler chicken flocks were monitored and preliminary diagnosed for determining the most prevalent Avian Influenza Virus subtype circulating in Egypt. The preliminary diagnosis was based on flock history, clinical examination, PM examination, HA test and virus isolation in SPF-ECEs. Diagnosis of AI was confirmed by carrying out of RRT-PCR assay. Twenty seven out of 31 samples (27/31) gave haemagglutination activity after isolation in SPF-ECEs. By using RRT-PCR, ten out of 31 samples (10/31) were found to be positive for AIV (H5). Mixed infection was common in the monitored farms where, (AIV H5 and NDV) were found to be positive in 3/31, (AIV H9 and NDV) were positive in 11/31; (AIV H5, H9 and NDV) were found in 7/31. Mono infection was found to be rare where 3 out of 31 (3/31) were positive for AIV (H9) only, 3/31 were positive for NDV only and 4/31 were found to be negative for the previously tested viruses and there was no detectable AIV (H7). All HPAIV (H5) subtype positive samples were accompanied with mixed infection that led to high mortalities. AIV (H9) subtype was the most prevalent where it was recorded in 21/31 (67.7%).
In a trial to control the wide spread of HPAI H5N1 and NDV outbreaks among poultry flocks in Egypt, six formulae were prepared from monovalent and bivalent inactivated vaccines for ND and AI (H5N1) based on the use of two inactivators (formalin and Binary ethylenimine (BEI)) and two adjuvants (Montanide ISA 71 and Drakeol 5). BEI did not influence the antigenicity of both virus suspensions (AIV and NDV). The prepared vaccines in addition to an imported bivalent vaccine were evaluated in SPF chickens as well as commercial ones. Challenge and humoral immune response were the main evaluation criteria. The protection percent against HPAIV (A/duck/Egypt/CLEVB-24_N00238/2015) was higher for Montanide adjuvanted vaccines and imported vaccine group than Drakeol adjuvanted groups in SPF and broiler chickens. In ND vaccinated groups, monovalent vaccines prepared with Montanide and Drakeol adjuvants in addition to bivalent imported vaccine induced higher protection percent against velogenic NDV genotype VIId than that induced by combined vaccines prepared with the same adjuvants in SPF chickens while in commercial ones, protection percent was higher for Montanide adjuvanted vaccines than for Drakeol adjuvanted groups and imported vaccine group.
In conclusion, the results of the present study have shown the presence of co-circulation of AIV (H5) and (H9) in addition to NDV in Egyptian field for broiler chicks and no appearance for AIV (H7). Montanide ISA 71 adjuvant improved the immune response of vaccinated birds.