الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 173 |  |  |
| | | from | 173 | | |
Abstract
IB continues to be a threat for chicken production in Egypt, even
in vaccinated flocks. In broilers, IB is typically associated with respiratory
disease and/or renal damage, and increased mortality at the end of fattening
cycle. The co-infection with other respiratory viruses (NDV, H5N1 and
H9N2) play important role in IBV outbreaks and exaggeration of its
problems. Severe economical losses due to lose weight, diarrhea, and
mortalities recorded. There are more than one strain of IBV co-circulating
in the Egyptian poultry farms, among 19 IBV field isolates detected in this
study, 4 strains could be typed, the predominant strain was the Egyptian
variant-2 while the strain related to Mass,793B and Egyptian variant-1
were identified in a lower percentage. Isolation of IBV separately is
difficult due to the co-infection with other respiratory viruses. The
protection from the commercial IBV vaccines in commercial broilers was
studied and there were no sufficient protection against IBV variant-2
challenge. The co-infection of E.coli with IBV exaggerates IBV
mortalities, from no mortalities in IBV challenged chickens to 25% (2\8) in
chickens challenged with IBV and E.coli and increases the losses through
reduction of body weight gain.