Thesis (Ph.D.) - Cairo University - Faculty of Veterinary Medicine - Department of Virology

In the current study two experiments were concluded. The first experiment was performed on 300 HAU vaccines (group 1, 2, 3 for local prepared, 4, 5, 6 for imported) while, the second one using 500HAU vaccines. Each experiment compare the effect of vaccination age (1, 5, 10 days) which reflects the effect of maternal derived antibodies on the vaccination. Challenge test revealed 0, 1³, 80% and 0, 1³ and 86% of protection in groups 1,2,3 and groups 4, 5, and 6; respectively. rRT-PCR and virus isolation revealed that vaccination at 1 and 5 days of age demonstrated 100% shedding at 3, 5, 7 and 10 days post challenge. However, groups 3 and 6 which were vaccinated at 10 days of age revealed difference in shedding pattern where group 3 (local prepared 300HAUvaccine) showed 100 shedding by rRT-PCR and 100%, 60% and 60 % of the chickens in tracheal swabs and 100%, 80% and 60% in cloacal swabs when tested by virus isolation in eggs at 3, 5, 7 and 10 days post challenge; respectively

Issued also as CD