Experimental Studies and Field Trials with Recombinant Fowlpox Vaccine in Broilers in Mexico

The use of a recombinant Avian Influenza-Fowlpox vectored vaccine has been considered in Mexico as an additional strategy to control low pathogenic avian influenza (LPAI) and high pathogenic avian influenza (HPAI) if an outbreak occurs again. There have been experiments conducted in animal biocontainment facilities. The results of these experiments demonstrate that the vaccinated chicks developed HI antibody titers less than 1:80. 95% of the vaccinated chicks were protected from challenge 14 days after vaccination (AV) and 100% were protected when challenged at 21 days of age. After a risk analysis of the vaccine was completed, two field trials were conducted in two states; 48,000 and 32,000 broilers were vaccinated. The results show that the recombinant vaccine did not induce any adverse effect on the production parameters of the vaccinated broilers. No mortality associated with vaccination was detected. Less than five percent of the sampled birds had serum HI titers and these titers were low. Protection after challenge was between 90 and 100%. No horizontal transmission was detected. The recombinant vaccine was shown to be safe, effective, and to prevent signs and mortality associated with the challenge of the HPAI virus.