Efficacy evaluation of Razi Infectious Bronchitis Live Attenuated Vaccine 793/B08IR Strain

Vaccines that are currently used to control infectious bronchitis are vaccines containing 793/B strain. Following the evidence of 793/B viral infection in most of the country's poultry farms, a live vaccine for virulent infectious bronchitis strain 793/B08IR was developed at the Razi Institute. The purpose of this project was to evaluate the efficacy of vaccine 793/B08IR based on the OIE protocol by assessing the activity of ciliary activity of IBV vaccinated birds after the challenge of acute viruses. The results of the study of trachea after the challenge of acute virus in the Razi, imported and control groups were 1.5, 1.7 and 4, respectively. According to the standard, a score of less than or equal to 2 indicates the immunity of the bird vaccinated against the acute virus, and a score of more than 2 indicates the lack of resistance of the bird. The results indicated that Razi vaccine was highly effective compared to the imported vaccine, and 100% of the birds vaccinated against the acute virus resisted, while all the birds in the control group stopped full trachea without any resistance acute virus showed. Serological tests (ELISA) and serum neutralization (SN) also showed a significant increase in serum titer compared to the control group.