title: Further evidence for infection of pigs with human-like H1N1 influenza viruses in China.
abstract: Classical swine and avian-like H1N1 influenza viruses were reported widely in swine population worldwide, but human-like H1N1 swine viruses were reported occasionally. In 2006, a human-like H1N1 swine virus (A/swine/Guangdong/96/06) was isolated from pigs in Guangdong province, which was reported in China for the first time. To get further evidence for infection of pigs with human-like H1N1 influenza viruses, we analyzed eight gene segments of three human-like swine H1N1 viruses (A/swine/Guangdong/96/06, A/swine/Tianjin/01/04 and A/swine/Henan/01/06) isolated in China. All the eight genes of the three viruses are highly homologous to recent (about 2000) and early (1980s) human H1N1 influenza viruses, respectively. Phylogenetic analyses revealed that A/Swine/Guangdong/96/06 was directly derived from about 2000 human H1N1 influenza viruses, while A/swine/Tianjin/01/04 and A/swine/Henan/01/06 seemed to be descendants of human H1N1 viruses circulating in 1980s. Seroprevalence of our isolate (A/swine/Guangdong/96/06) confirmed the presence of human-like H1N1 virus in pigs in China. Existence of these influenza viruses, especially older viruses (A/swine/Tianjin/01/04 and A/swine/Henan/01/06), indicates that human-like H1N1 influenza viruses may remain invariant for long periods in pigs and provides the evidence that pigs serve as reservoirs of older influenza viruses for human pandemics.
authors.affiliation: Division of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
authors.forename: Hai
authors.initials: H
authors.lastname: Yu
authors.forename: Yan-Jun
authors.initials: YJ
authors.lastname: Zhou
authors.forename: Guo-Xin
authors.initials: GX
authors.lastname: Li
authors.forename: Gui-Hong
authors.initials: GH
authors.lastname: Zhang
authors.forename: Hui-Li
authors.initials: HL
authors.lastname: Liu
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Yan
authors.forename: Ming
authors.initials: M
authors.lastname: Liao
authors.forename: Guang-Zhi
authors.initials: GZ
authors.lastname: Tong
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002681:China / Q000453:epidemiology; D019143:Evolution, Molecular; D005814:Genes, Viral; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D008969:Molecular Sequence Data; D009976:Orthomyxoviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D016415:Sequence Alignment; D017423:Sequence Analysis, RNA; D012689:Sequence Homology, Nucleic Acid; D016036:Seroepidemiologic Studies; D013552:Swine / Q000821:virology*; D013553:Swine Diseases / Q000453:epidemiology* / Q000821:virology
chemical_list: D000914:Antibodies, Viral; D012367:RNA, Viral