TY  - BOOK
AU  - Amena Abdelmoeid Sayed Mohamed
AU  - Ayman Hany Mahmoud Eldeeb , 
AU  - Hussein Aly Hussein Ahmed , 
AU  - Mounir Mohamed Elsafty , 
TI  - Efficacy of inactivated AI H5 vaccines in  SPF chicks against challenge with  Egyptian H5N8 clade 2.3.4.4b viruses  isolated in 2017 and 2018 / 
PY  - 2021///
CY  - Cairo : 
PB  - Amena Abdelmoeid Sayed Mohamed , 
KW  - Avian influenza
KW  - Clade 2.3.4.4b
KW  - Highly pathogenic H5N8
N1  - Thesis (M.Sc.) - Cairo University - Faculty of Veterinary Medicine - Department of Virology; Issued also as CD
N2  - Vaccination is the routinely used tool for control of highly pathogenic avian influenza (HPAI) H5N8subtype in Egypt. Inactivated avian influenza vaccines are the most frequently registered and commercially used against avian influenza (AI)infection in poultry farms. Both genetic and antigenic mismatching between the seed strain used invaccine and the recent circulating HPAI H5N8 viruses may affect the efficiency of commercial vaccines used in AIcontrol in Egypt.In this study, we evaluated inactivatedAI commercial vaccines (H5N1, H5N2 and H5N3) in challenge trials using specific pathogen free (SPF) chicks at 2 and 3 weeks post vaccination (WPV). Two Egyptian HPAI H5N8 viruses isolated in 2017 and 2018 clade 2.3.4.4bwere used. Survival percentages, antibody titers and the virus shedding titers as well as the histopathological changes in kidney and spleen were recorded.All studied vaccines revealed protection percentages between 70 to 100 % within 10 dayspost challenge. Haemagglutination inhibition (HI)results of sera samples showed antibody titers ranged from 0.6 to 5.4 log2 starting 1 week (PV) with the highest titers at 4thWPV. Vaccinated challenged SPF chicks showed remarkable virus shedding reduction with an average of 2 log10 compared to control birds. Various histopathological lesions with different scores were demonstrated. H5N1 and H5N3 AI vaccines were the most effective against the challenge HPAI H5N8 viruses. We recommend annual evaluation of the currently used vaccines using the most prevalent challenge H5N8 viruses isolated from field outbreaks in poultry farms based on the annual surveillance for AI in Egypt
UR  - http://172.23.153.220/th.pdf
ER  -