title: Serologic screenings for H7N9 from three sources among high-risk groups in the early stage of H7N9 circulation in Guangdong Province, China.
abstract: BACKGROUND
  The aim of this study was to assess the prevalence of the novel avian influenza A virus (H7N9) in three high risk groups. The groups were divided into those exposed through infected individuals, those exposed through poultry and those individuals exposed through the external environment, in the early stage of the epidemic in Guangdong Province, which is located in the southern region of China.
  
  
  METHODS
  Serologic studies were conducted among samples collected from individuals who had close contact with the first H7N9 infected patient reported in Guangdong Province, those who were most likely exposed to the first group of H7N9 infected poultry, and those who might have been exposed to H7N9 in the environmental settings, namely hemagglutinin inhibition (HI) and microneutralizaiton(MN) assays using three viruses as antigens.
  
  
  RESULTS
  The alignment results of the viral sequences indicated the similarity of the HA gene sequence among viruses from exposure to infected poultry, infected humans and contaminated environments were highly conserved. Seven samples of individuals exposed to contaminated environments were positive in the HI assay and one sample among them was positive in the MN assay using poultry H7N9 virus as the antigen. One sample was positive against human H7N9 virus and 3 samples were positive against environmental H7N9 among those that were in contact with infected patients in HI assay. None of these were positive in MN assay. All HI titers of the 240 samples from those individuals in contact with infected poultry were less than 40 aganist the antigens from three viruses.
  
  
  CONCLUSIONS
  The results suggest that when the H7N9 virus was in the early stages of circulation in Guangdong Province, the antigenic sites of the HA proteins of the H7N9 strain isolated from different hosts were highly conserved. The risk of new infection is low in individuals who have contact with the infected patients, poultry or a contaminated environment in the early stages of the circulation of the H7N9 virus.
authors.forename: Jie
authors.initials: J
authors.lastname: Wu
authors.forename: Lirong
authors.initials: L
authors.lastname: Zou
authors.forename: Hanzhong
authors.initials: H
authors.lastname: Ni
authors.forename: Lei
authors.initials: L
authors.lastname: Pei
authors.forename: Xianqiao
authors.initials: X
authors.lastname: Zeng
authors.forename: Lijun
authors.initials: L
authors.lastname: Liang
authors.forename: Haojie
authors.initials: H
authors.lastname: Zhong
authors.forename: Jianfeng
authors.initials: J
authors.lastname: He
authors.forename: Yingchao
authors.initials: Y
authors.lastname: Song
authors.forename: Min
authors.initials: M
authors.lastname: Kang
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Jinyan
authors.initials: J
authors.lastname: Lin
authors.affiliation: Center for Disease Control and Prevention of Guangdong Province, Guangzhou 511430, China. kecw2011@sina.com.
authors.forename: Changwen
authors.initials: C
authors.lastname: Ke
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology*; D002642:Chick Embryo; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D005260:Female; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D006801:Humans; D007223:Infant; D064766:Influenza A Virus, H7N9 Subtype / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D005585:Influenza in Birds / Q000453:epidemiology / Q000635:transmission / Q000821:virology; D007251:Influenza, Human / Q000453:epidemiology / Q000276:immunology* / Q000635:transmission / Q000821:virology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010802:Phylogeny; D011200:Poultry; D011201:Poultry Diseases / Q000453:epidemiology / Q000635:transmission / Q000821:virology; D016415:Sequence Alignment; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; C109963:hemagglutinin, avian influenza A virus