Efficacy of Inactivated Avian Influenza H5N1 Vaccine in SPF chicken against Avian Influenza Viruses H5N2 and H5N8 (Egyptian Isolates)

Avian influenza (AIV) viruses in Egypt compromise the poultry industry. Infections in poultry flocks have been reported after vaccination. In our study available inactivated avian influenza vaccine H5N1 was evaluated for its efficacy against challenging with the recently isolated HPAI H5N2 (A/chicken/EG/16194V/2016) and H5N8 (HPAI clade 2.3.4.4 (A/green-wingedteal/ Egypt/871/2016(H5N8)(871/H5N8). our study had been achieved using SPF chickens which were divided into four groups .They were vaccinated at one , five , ten and twelve day old, then serologically monitoring on a weekly basis post vaccination (PV) for the 1st month, and follow immunity every month till the 6th month using (Haemagglutination Inhibition) HI test againstH5N1(HPAIclade2.2.1.2(A/chicken/Egypt/D10552B/2015(H5N1)(D10552BH5N1),H5N2(A/chicken/EG/16194V/2016)andH5N8(HPAIclade2.3.4.4(A/greenwingedteal/Egypt/871/2016(H5N8)(871/H5N8), then challenge test were conducted at 2nd ,3rd and 4th weeks PV using the recently isolated H5N2 and H5N8 field strains challenge viruses , tracheal and cloacal swabs were collected for detection of virus shedding which was calculated according to Spearman-Karber method (1961).. Our results indicate that the vaccine provides protection against different subtypes of viruses and decreases virus shedding from the challenged chicken.