الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 142 |  |  |
| | | from | 142 | | |
Abstract
Respiratory tract infections are of great negative impact in poultry industry. Here, a total of 303 samples were collected from diseased chickens [layer (n=101) and broilers (n=87)] and recently dead chickens [layer (n=65) and broilers (n=50)] during the period from February 2019 to September 2020. These samples were subjected for determining the existence of H. paragallinarum by conventional microbiological techniques. Serological characterization of the isolates was performed to determine prevalence of serotypes in Egypt. Antimicrobial susceptibility testing of the isolates was applied using disc diffusion method. Finally, vaccination and immunological evaluation of a previously prepared local vaccine was performed with challenging of chickens against H. paragallinarum
The result revealed that overall prevalence of H. paragallinarum in layer chickens was 19.3% (32/166), while no isolates obtained from broilers.
On blood agar, characteristic typical satellite growth pattern adjacent to the feeder colony (S. aureus) was detected, while dewDROP colonies were characteristic on chocolate agar.