Efficacy of infectious bronchitis vaccines prepared from local strains and their comparison with imported vaccines
2000
Khanzada, Z.A.
During present investigation, the organs of the naturally infected chickens, broilers and layers with infectious bronchitis virus from different poultry farms located around Sakrand, District Nawab Shah, Sindh, Pakistan were collected and brought to Sindh, Poultry Vaccine Production Centre Korangi, Karachi, for isolation and vaccine preparation. Two strains of virus were isolated from infected organs and recognized as ZIBV and 3IBV. These two strains were also subjected for vaccine preparation and their efficacy in immune response was compared to imported vaccines. Locally prepared vaccines were ZIBV and 3IBV and while imported were TAD and NOVA. All four vaccines were administered to chicks by intramuscular and intraocular routes. TAD showed a significant (p0.05) HI antibody titer at week 2 post vaccination and remained up to week 4 and declined to HI5.50. In contrast to above vaccine, 3IBV responded promptly and produced significant (P less than 0.05) HI293 titer on days 7 post-vaccination and declined at level of HI3 on days 42. On the other hand, NOVA was found highly reactive and produced HI293 titer on days 7 post vaccination but trend of declination in its titer was completely different from the above vaccines. On days 14, HI antibody titer in the sera reached at level of HI4 and remained mostly similar on the following weeks of investigation. Whereas locally prepared vaccine ZIBV was regarded as less immunogenic in its nature. Furthermore, that all chicks which were vaccinated by four different vaccines during study when challenged with IBV virus, only 3BV and TAD were found the vaccines of high immunogenic and could protect birds from infectious, bronchitis virus. No cross reactivity was seen among the vaccines.
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