ABSTRACT
During the period 2006 to 2009, a total of 1096 blood samples from 92 chicken flocks [21 of breeder flocks,63 of commercial layer flocks and 8 broiler flocks], were collected from different govemorates [Giza, Qalubia, Sharkia and Dakahlia] and tested for determination of hemagglutinationinhibition [HI] titers against Avian Influenza [Al]. All of the surveyed farms applied blind vaccination programs without serological estimation to MDA and actively acquired humoral immune response to determine timing of priming or boosting[s]. HI titer equal to or less than 2 was detected in 76 flocks [82.6%], and there were 16 flocks [17.4%] showed low antibody titer [<4 log2]. The results indicated that MDA persisted for 28 days duration after hatchling and these MDA may interfere with early vaccination [less than 2 weeks of age]. Early vaccinations within first week of age, with full vaccine dose, were frequently and blindly applied due to panic of AT. The results of evaluation of such flocks at marketing age [30. 42 days] revealed suboptimal HI titer. For the control of avian influenza, a rapid diagnosis by detecting the causative virus and identifying its subtype is essential. A rapid diagnosis kit for identification of AT by rapid antigen kits [Type A and H5 kit] was used for detection of AIV in three hundred samples, positive samples were 67, [22.33%]. Out of 82 samples from Qalubia, positive samples were 18, [21.95%], samples from Giza were 56, positive samples 11 were positive, [19.64%], 13/68 samples from Dakahlia were positive [19.11%] and 2 5/94 samples from Sharkia were positive [26.59%]