IMMUNOGENICITY AND SAFETY OF CHICKEN EMBRYO FIBROBLAST ADAPTED FOWLPOX VACCINE

ABSTRACT Background The use of chorioallantoic membranes (CAM) route for the propagation of fowlpox virus (FPV) is the method applied in the production of potent and effective fowlpox vaccine at the National Veterinary Research Institute (NVRI), Vom. However, production insufficiency has led to inadequate supply of vaccine to meet farmer’s demands. This has left large number of susceptible and unvaccinated flocks with outbreaks of the disease being reported in Nigerian. Aim This study adapted FPV to Chicken embryo fibroblast (CEF) cell culture and assessed its immunogenicity and safety of the resulting vaccine in comparison to a locally produced CAM-based FPV vaccine. Methods The FPV were propagated on CAM and CEF of 9 to 12 day old developing chicken embryos. The vaccine harvests were subjected to quality checks, titrated, and used in vaccinating experimental birds via the wing web to monitor for takes, seroconversion, and safety. Results The FPV was successful adapted to CEF as demonstrated by the attainment of 80 to 90% cytopathic effect within 71 to 115 hours in the different passages. Both the CEF and CAM-adapted vaccine harvests were highly replicative producing titres of above 10 6.0 /ml TCID 50, but higher titres of 10 8.25 /ml TCID 50 was recorded in the CEF-adapted vaccines. Experimentally vaccinated birds showed 100% takes within 3 to 4 days post-vaccination, with no adverse effects recorded. Conclusion This research reported successful development and adaptation of FPV to CEF that was safe and immunogenic, with the potential for its use in the production of self-sufficiency vaccine for fowlpox prevention and control in poultry.