Trial for Preparation and Evaluation of Combined Inactivated Vaccine for the Protection against Riemerella anatipestifer and Avian Influenza (H5N1) in Ducks

Riemerella anatipestifer and Avian Influenza infections cause major economic losses in the duck industry through high mortality rates, poor feed conversion, increased condemnations, and high treatment costs. A field trial was conducted to evaluate the immunogenicity of an experimentally multivalent inactivated R. anatipestifer and Avian Influenza (H5N1) vaccine. In this study a combined inactivated Montanide ISA 71 R. anatipestifer and Avian Influenza (H5N1) vaccine was prepared then the immunization potency and protective efficacy were evaluated through experimental application on Pekin ducklings. The peak of humeral immune response against R. anatipestifer as measured by indirect haemagglutination inhibition test (HI) was at the 6th week post primary vaccination while it was at the 4th week when boostering 3 weeks after primary vaccination and 3rd week when boostering 8 weeks after primary vaccination; meanwhile AI immune response as measured by (HI) reached the peak at the 5thweek post primary vaccination and at 4th week for single AI and 5thweek for combined RA and AI vaccines when boostering 3 weeks after primary vaccination and 5th week when boostering 8 weeks after primary vaccination . Regarding the challenge test, the protection percentage were 70% against both RA1 and RA2 virulent strains in RA vaccine and 75% in combined RA and AI vaccine after challenge 3 weeks post primary vaccination, while it was 80% against RA1 and RA2 virulent strains in RA vaccine and 85% in combined RA and AI vaccine after challenge 3 weeks post boostering. In conclusion the combined prepared R. anatipestifer and Avian Influenza (H5N1) vaccine succeeded in eliciting protective antibody titers and satisfactory protection against both R. anatipestifer and Avian Influenza (H5N1) diseases.