الفهرس 
الملخص العربى
ِِAim of the present workOnly 14 pages are availabe for public view
 |  | from | 98 |  |  |
| | | from | 98 | | |
Abstract
The prevalence of infectious coryza in broiler and laying flocks at El-Menia governorate was studied. Three hundreds and fifty alive and freshly dead chickens of different ages and breeds were subjected to clinical, post-mortem and bacteriological examination. Isolated Haemophillus organisms were identified morphologically, biochemically, biologically and serologically as Haemophillus paragallinarum where 4 strains belonged to serotype 1 and 5 strains belonged to serotype 2.Isolated Haemophillus organisms were pathogenic to chicken embryos causing death within 24-48 hours with congestion of dead embryos and its embryonic membrane. In chickens the pathogencity of the isolates depended upon the route of infection. All isolates were pathogenic to chickens by both intrasinus and intranasal inoculation. The monovalent bacterins prepared either from serotype 1 or serotype 2 were found to be efficient in protection the vaccinated birds against homologous challenge while failed to protect against hetrologous challenge which indicated that the lack of cross-protection among two serotypes.