title: Different evolutionary trends of swine H1N2 influenza viruses in Italy compared to European viruses.
abstract: European H1N2 swine influenza viruses (EU H1N2SIVs) arose from multiple reassortment events among human H1N1, human H3N2, and avian influenza viruses. We investigated the evolutionary dynamics of 53 Italian H1N2 strains by comparing them with EU H1N2 SIVs. Hemagglutinin (HA) phylogeny revealed Italian strains fell into four groups: Group A and B (41 strains) had a human H1 similar to EU H1N2SIVs, which probably originated in 1986. However Group B (38 strains) formed a subgroup that had a two-amino acid deletion at positions 146/147 in HA. Group C (11 strains) contained an avian H1 that probably originated in 1996, and Group D (1 strain) had an H1 characteristic of the 2009 pandemic strain. Neuraminidase (NA) phylogeny suggested a series of genomic reassortments had occurred. Group A had an N2 that originated from human H3N2 in the late 1970s. Group B had different human N2 that most likely arose from a reassortment with the more recent human H3N2 virus, which probably occurred in 2000. Group C had an avian-like H1 combined with an N2 gene from one of EU H1N2SIVs, EU H3N2SIVs or Human H3N2. Group D was part of the EU H3N2SIVs clade. Although selection pressure for HA and NA was low, several positively selected sites were identified in both proteins, some of which were antigenic, suggesting selection influenced the evolution of SIV. The data highlight different evolutionary trends between European viruses and currently circulating Italian B strains and show the establishment of reassortant strains involving human viruses in Italian pigs.
authors.affiliation: Department of Virology, Istituto Zooprofilattico Sperimentale della Lombardia ed Emilia Romagna, Via Bianchi, 9, 25124 Brescia, Italy. anamaria.morenomartin@izsler.it.
authors.forename: Ana
authors.initials: A
authors.lastname: Moreno
authors.forename: Elena
authors.initials: E
authors.lastname: Gabanelli
authors.forename: Enrica
authors.initials: E
authors.lastname: Sozzi
authors.forename: Davide
authors.initials: D
authors.lastname: Lelli
authors.forename: Chiara
authors.initials: C
authors.lastname: Chiapponi
authors.forename: Massimo
authors.initials: M
authors.lastname: Ciccozzi
authors.forename: Gianguglielmo
authors.initials: G
authors.lastname: Zehender
authors.forename: Paolo
authors.initials: P
authors.lastname: Cordioli
mesh_terms: D000818:Animals; D005060:Europe / Q000453:epidemiology; D019143:Evolution, Molecular; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D057221:Influenza A Virus, H1N2 Subtype / Q000235:genetics* / Q000378:metabolism; D007558:Italy / Q000453:epidemiology; D008969:Molecular Sequence Data; D009439:Neuraminidase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D009976:Orthomyxoviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D010802:Phylogeny; D017433:Protein Structure, Secondary; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D012621:Seasons; D012641:Selection, Genetic; D017423:Sequence Analysis, RNA / Q000662:veterinary; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology* / Q000821:virology
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D009439:Neuraminidase