Abstract
This study was conducted to investigate the prevalence of Newcastle Disease, Avian Influenza, Infectious Bronchitis, and Infectious laryngotracheitis in some regions of Tripoli-Libya. Serum samples were collected from Four broiler farms in Wadi Alrabea area, two layer farms and one backyard farm in Gaser Bin Gasher, two layer farms in Alswani and one backyard farm in Zliten City and screened for the presence of antibodies against LPAI-H9, HPIA-H5, HPIA-H7, ND, IB 4/91 strain using the HI test and antibodies against ILT virus by ELISA. The overall seroprevalence of H9, H5, H7, ND, IB4/91 and ILT was 26.5%,0%,0%,, 29.5%,43% and 30% respectively. All sera tested for AI-H5 and AI-H7 were negative. In Wadi Alrabea flocks, seroprevalence of H9, H5, H7, ND, IB4/91 and ILT was 44%, 0%, 0%, 16.28%, 32.56% and 0% respectively. Where as in Gaser Bin Ghasher, was 24%,0%, 0%, 33.87, 36.29% and 39% respectively. In Alswani, the seroprevalence was 8.70%, 0%, 0%, 52.17%, 54.35% and 54.3%. The seroprevalence of H9, H5, H7 in Gaser Bin Ghasher backyard chickens was 23%, 0%, 0% respectively and the seroprevalence of H9, H5, H7, ND, IB4/91 of Zliten backyards was 12%, 0%, 0%, 12%, 96% respectively. Further investigations are recommended to identify the circulating virus genotypes and models of transmission for better understanding of these viruses epidemiology in backyard chickens in Libya. Vaccination of backyard chickens against ND using heat resistant strain is highly recommended.