Abstract:
This dissertation is divided into 3 parts. First, the effect of inoculation dose of a Thai HPAI-H5N1 (CUK2) virus was evaluated, 107 quails were divided into 4 groups. At 9-week-old, 16 quails in groups 1-3 (n=32 each) were inoculated with 10⁷, 10⁵ and 10³ EID₅₀ of A/chicken/Thailand/CUK2/04 virus, respectively. One day later 16 quails in each group were added. Group 4 (n=11) was negative control group. Quails have been observed for 3 weeks. Oropharyngeal and cloacal swabs were analyzed for viral shedding. The death time and viral shedding suggested that 10⁵ EID₅₀ of virus per quail was selected for animal challenge in vaccination experiment. Second, serological response to inactivated vaccine was investigated, 60 quails were divided into 3 groups (n=20 each), duplicate vaccinated groups and unvaccinated group. The inactivated vaccine, A/chicken/Mexico/232/94 (H5N2) virus, was administered at the age of 3 (half dose) and 7 (full dose) weeks. Blood samples were analyzed for serological response. The result indicated that twice vaccination induced significantly increase HI antibody. Third, efficacy of inactivated vaccine was evaluated, 48 quails were divided into 3 groups (n=16 each), duplicate vaccinated groups and unvaccinated group. The inactivated vaccine was administered at the age of 3 (half dose) and 7 (full dose) weeks. At the age of 10 weeks, 8 quails in each group were inoculated with CUK2 virus, One day later 8 quails in each group were added. Quails have been observed for 3 weeks. Oropharyngeal and cloacal swabs were analyzed for viral shedding. The results indicated that twice vaccination could reduce the mortality and the viral shedding. In conclusion, this dissertation demonstrated that given vaccination program induced specific antibody response and partially protected quail from HPAI-H5N1 virus but not effectively prevented transmission of the virus.
