Aim: The aim of the current study was to evaluate a trivalent inactivated oil-emulsion vaccine against different clades highly pathogenic avian influenza (AI) viruses including AI-H5N8 and the virulent genotype VII NDV virus (vNDV).
Materials and methods: the vaccine studied herein is composed of AI viruses rg A/Chicken/Egypt/ME1010/2016 (clade 188.8.131.52), H5N1 rgA/Chicken/Egypt/RG-173CAL/2017 (clade 184.108.40.206) and Newcastle disease virus “NDV” (LaSota NDV/CK/Egypt/11478AF/11); all used at a concentration of 108 EID50/bird and mixed with Montanide-ISA70 oil adjuvant. Two weeks old Specific Pathogen Free (SPF) chickens were immunized subcutaneously with 0.5 ml of the vaccine and hemagglutination inhibition (HI) antibody titers were monitored weekly. Intranasal challenge was conducted 4 weeks post vaccination (PV) using 106EID50/0.1ml of the different virulent AI-H5N1 viruses representing clades 2.2.1, 220.127.116.11, 18.104.22.168, 22.214.171.124b-H5N8 and the vNDV.
Results: the vaccine induced HI antibody titers of >6log2 against H5N1 and NDV viruses 2 weeks post vaccination. There was a clinical protection of 100% against all H5N1 viruses and vNDV, whereas 93.3% protection was found against HPAI H5 clade-2.2.1 and HPAI H5 clade-126.96.36.199b viruses. Challenged birds showed a significant decrease in the titer of virus shedding
Avian influenza, H5N1, H5N8, Newcastle diseases virus, H5ND, Trivalent vaccine, Egypt