title: Protective efficacy of an inactivated vaccine against H9N2 avian influenza virus in ducks.
abstract: BACKGROUND
  Wild ducks play an important role in the evolution of avian influenza viruses (AIVs). Domestic ducks in China are known to carry and spread H9N2 AIVs that are thought to have contributed internal genes for the recent outbreak of zoonotic H7N9 virus. In order to protect animal and public health, an effective vaccine is urgently needed to block and prevent the spread of H9N2 virus in ducks. We developed an inactivated H9N2 vaccine (with adjuvant Montanide ISA 70VG) based on an endemic H9N2 AIV and evaluated this vaccine in ducks.
  
  
  RESULTS
  The results showed that the inactivated H9N2 vaccine was able to induce a strong and fast humoral immune response in vaccinated ducks. The hemagglutination inhibition titer in the sera increased fast, and reached its peak of 12.3 log2 at 5 weeks post-vaccination in immunized birds and remained at a high level for at least 37 weeks post-vaccination. Moreover, viral shedding was completely blocked in vaccinated ducks after challenge with a homologous H9N2 AIV at both 3 and 37 weeks post-vaccination.
  
  
  CONCLUSIONS
  The results of this study indicate that the inactivated H9N2 vaccine induces high and prolonged immune response in vaccinated ducks and are efficacious in protecting ducks from H9N2 infection.
authors.affiliation: Innovation Team for Ecology and Virology of Animal Influenza Virus, Shanghai, 200241, China. tengqy@shvri.ac.cn.|Department of Avian Infectious Disease, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China. tengqy@shvri.ac.cn.
authors.forename: Qiaoyang
authors.initials: Q
authors.lastname: Teng
authors.affiliation: Innovation Team for Ecology and Virology of Animal Influenza Virus, Shanghai, 200241, China. 471635611@qq.com.
authors.forename: Weixia
authors.initials: W
authors.lastname: Shen
authors.affiliation: Innovation Team for Ecology and Virology of Animal Influenza Virus, Shanghai, 200241, China. liuqinfang@shvri.ac.cn.|Department of Avian Infectious Disease, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China. liuqinfang@shvri.ac.cn.
authors.forename: Qinfang
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Innovation Team for Ecology and Virology of Animal Influenza Virus, Shanghai, 200241, China. 15114665435@163.com.
authors.forename: Guangyu
authors.initials: G
authors.lastname: Rong
authors.affiliation: Innovation Team for Ecology and Virology of Animal Influenza Virus, Shanghai, 200241, China. 634760224@qq.com.
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.affiliation: Innovation Team for Ecology and Virology of Animal Influenza Virus, Shanghai, 200241, China. lixuesong@shvri.ac.cn.|Department of Avian Infectious Disease, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China. lixuesong@shvri.ac.cn.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Li
authors.affiliation: Innovation Team for Ecology and Virology of Animal Influenza Virus, Shanghai, 200241, China. vetchj@shvri.ac.cn.|Department of Avian Infectious Disease, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China. vetchj@shvri.ac.cn.
authors.forename: Hongjun
authors.initials: H
authors.lastname: Chen
authors.affiliation: Innovation Team for Ecology and Virology of Animal Influenza Virus, Shanghai, 200241, China. yangjianmei@shvri.ac.cn.|Department of Avian Infectious Disease, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China. yangjianmei@shvri.ac.cn.
authors.forename: Jianmei
authors.initials: J
authors.lastname: Yang
authors.affiliation: Innovation Team for Ecology and Virology of Animal Influenza Virus, Shanghai, 200241, China. lizejun@shvri.ac.cn.|Department of Avian Infectious Disease, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China. lizejun@shvri.ac.cn.
authors.forename: Zejun
authors.initials: Z
authors.lastname: Li
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002681:China; D004372:Ducks; D006385:Hemagglutination Inhibition Tests; D053127:Influenza A Virus, H9N2 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D005585:Influenza in Birds / Q000276:immunology / Q000517:prevention & control*; D009829:Oleic Acids / Q000008:administration & dosage; D016896:Treatment Outcome; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology; D017201:Virus Shedding
chemical_list: D000276:Adjuvants, Immunologic; D000914:Antibodies, Viral; D007252:Influenza Vaccines; D009829:Oleic Acids; D015164:Vaccines, Inactivated