title: Novel swine influenza virus subtype H3N1, United States.
abstract: Influenza A virus infects various animal species and transmits among different hosts, especially between humans and swine. Swine may serve as a mixing vessel to create new reassortants that could infect humans. Thus, monitoring and characterizing influenza viruses in swine are important in preventing interspecies transmission. We report the emergence and characterization of a novel H3N1 subtype of swine influenza virus (SIV) in the United States. Phylogenetic analysis showed that the H3N1 SIVs may have acquired the hemagglutinin gene from an H3N2 turkey isolate, the neuraminidase gene from a human H1N1 isolate, and the remaining genes from currently circulating SIVs. The H3N1 SIVs were antigenically related to the turkey virus. Lung lesions and nasal shedding occurred in swine infected with the H3N1 SIVs, suggesting the potential to transmit among swine and to humans. Further surveillance will help determine whether this novel subtype will continue to circulate in swine populations.
authors.affiliation: Virus and Prion Disease of Livestock Research Unit, National Animal Disease Center, US Department of Agriculture/ARS, 2300 Dayton Avenue, Ames, IA 50010, USA.
authors.forename: Porntippa
authors.initials: P
authors.lastname: Lekcharoensuk
authors.forename: Kelly M
authors.initials: KM
authors.lastname: Lager
authors.forename: Ramesh
authors.initials: R
authors.lastname: Vemulapalli
authors.forename: Mary
authors.initials: M
authors.lastname: Woodruff
authors.forename: Amy L
authors.initials: AL
authors.lastname: Vincent
authors.forename: Jürgen A
authors.initials: JA
authors.lastname: Richt
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004279:DNA, Viral / Q000032:analysis*; D004197:Disease Reservoirs / Q000662:veterinary; D018562:Disease Transmission, Infectious / Q000662:veterinary; D006801:Humans; D007196:Indiana / Q000453:epidemiology; D009980:Influenza A virus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D008824:Michigan / Q000453:epidemiology; D008969:Molecular Sequence Data; D009976:Orthomyxoviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D010802:Phylogeny; D016415:Sequence Alignment / Q000662:veterinary; D013045:Species Specificity; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000821:virology*; D015047:Zoonoses
chemical_list: D004279:DNA, Viral