Thesis (Ph.D.) - Cairo University - Faculty of Veterinary Medicine - Department of Cilinical Pathology

Avian influenza virus; one of the most important zoonotic diseases that{u2019}s not only pose athreat to the poultry industry but also high risk to the humans and environment. Although; many efforts are made to control it to reduce its risk globally mainly through stamping out or vaccination particularly in Egypt, it{u2019}s still spreading and become endemic in Egypt since 2008. Therefore, recent attention has been directed to alternative medicine because of its many health benefits and antiviral effects. In this study we evaluated the antiviral efficacy of green tea extract on highly pathogenic avian influenza virus (H5N1).Different concentrations of methanolicgreen tea extract were inoculated into vero cell line and to ECE to study its cytotoxicity and antiviral effect in-vitro.120 one day old SPF chicks were divided into 8 groups (15 birds/group); group (A) negative control, group (B) GTE control, group (C) positive control, group (D) supplied with GTE from beginning of the experiment, group (E) supplied with GTE 4hs before challenge, group (F) supplied with GTE 24hs post challenge,group (G) vaccinated with inactivated vaccine (Re-1) on the 7th day old and group (H) supplied by GTE from beginning of the experiment and vaccinated. GTE used 5gm/literin drinking water. The challenge was applied on the 28th day old using HPAI (H5N1)106 EID50/100æl/bird through I/N rout.Our results revealed desirable effect in-vitroby marked decreasing in viral cytopathic effect on treated vero cells as well as decreasing the hemagglutinating titer in tested allantoic fluid of treated ECE group. Obvious antiviral efficacy of GTE was detected in-vivo including decreases in viral shedding of treated groups; particularly in vaccinated treated one, clear histopathologicalimprovement oflung of treated groups which confirmed by variable detection of viral antigen by immunohistochemistry and morphometric analysis

Issued also as CD