title: Avian influenza H9N2 seroprevalence among pig population and pig farm staff in Shandong, China.
abstract: BACKGROUND
  Shandong province of China has a large number of pig farms with the semi-enclosed houses, allowing crowds of wild birds to seek food in the pig houses. As the carriers of avian influenza virus (AIV), these wild birds can easily pass the viruses to the pigs and even the occupational swine-exposed workers. However, thus far, serological investigation concerning H9N2 AIV in pig population and pig farm staff in Shandong is sparse.
  
  
  METHODS
  To better understand the prevalence of H9N2 AIV in pig population and pig farm staff in Shandong, the serum samples of pigs and occupational pig-exposed workers were collected and tested for the antibodies for H9N2 AIV by both hemagglutination inhibition (HI) and micro-neutralization (MN) assays.
  
  
  RESULTS
  When using the antibody titers ≥40 as cut-off value, 106 (HI: 106/2176, 4.87%) and 84 (MN: 84/2176, 3.86%) serum samples of pigs were tested positive, respectively; 6 (HI: 6/287, 2.09%) and 4 (MN: 4/287, 1.39%) serum samples of the pig farm staff were positive, respectively; however, serum samples from the control humans were tested negative in both HI and MN assays.
  
  
  CONCLUSIONS
  These findings revealed that there were H9N2 AIV infections in pig population and pig farm staff in Shandong, China. Therefore, it is of utmost importance to conduct the long-term surveillance of AIV in pig population and the pig farm staff.
authors.affiliation: College of Basic Medicine, Taishan Medical University, Taian, 271000, China. songli@126.com.
authors.forename: Song
authors.initials: S
authors.lastname: Li
authors.affiliation: Animal Husbandry Bureau of Daiyue District, Taian, 271000, China. yufazhou@126.com.|College of Veterinary Medicine, Shanxi Agricultural University, Taigu, 030800, China. yufazhou@126.com.
authors.forename: Yufa
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: College of Life Sciences, Taishan Medical University, Changcheng Road 619, Taian, 271000, China. yuxinzhao@126.com.
authors.forename: Yuxin
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: College of Life Sciences, Taishan Medical University, Changcheng Road 619, Taian, 271000, China. wenbol@126.com.
authors.forename: Wenbo
authors.initials: W
authors.lastname: Li
authors.affiliation: College of Basic Medicine, Taishan Medical University, Taian, 271000, China. wengangs@126.com.
authors.forename: Wengang
authors.initials: W
authors.lastname: Song
authors.affiliation: College of Life Sciences, Taishan Medical University, Changcheng Road 619, Taian, 271000, China. zengminmiao@126.com.
authors.forename: Zengmin
authors.initials: Z
authors.lastname: Miao
mesh_terms: D000328:Adult; D000382:Agricultural Workers' Diseases / Q000276:immunology* / Q000821:virology; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D001717:Birds; D002681:China; D005260:Female; D006801:Humans; D053127:Influenza A Virus, H9N2 Subtype / Q000145:classification / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D005585:Influenza in Birds / Q000821:virology*; D007251:Influenza, Human / Q000276:immunology* / Q000635:transmission / Q000821:virology; D008297:Male; D008875:Middle Aged; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000635:transmission / Q000662:veterinary* / Q000821:virology; D010802:Phylogeny; D016036:Seroepidemiologic Studies; D013552:Swine; D013553:Swine Diseases / Q000276:immunology* / Q000635:transmission / Q000821:virology; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral