title: Molecular and phylogenetic analysis of the haemagglutinin gene of pandemic influenza H1N1 2009 viruses associated with severe and fatal infections.
abstract: The objectives of this research is molecular and phylogenetic analysis of pandemic influenza A(H1N1) 2009 strains that circulated in northern Greece, focusing on severe or fatal infections, identification of sequence variations in relation with the severity of the illness and comparison of circulating viruses with the vaccine strain. A total of 1598 infections were attributed to the novel influenza A(H1N1) virus. Molecular analysis revealed a number of variations at the HA1 sequences of northern Greek circulating strains, some of which were more frequent in viruses that caused severe or fatal infections. Such mutations, the most common being D222G, demand close monitoring to continuously assess associated risks. Phylogenetic analysis confirmed the close match of the majority of circulating strains with A/California/7/09. However it also reveals a trend of 2010 strains to accumulate amino acid variations and form new plylogenetic clades. Constant molecular surveillance is important to monitor the pathogenicity of circulating strains and evaluate the vaccine efficacy.
authors.affiliation: National Influenza Centre for Northern Greece, 2nd Laboratory of Microbiology, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece. amelidou@med.auth.gr
authors.forename: Angeliki
authors.initials: A
authors.lastname: Melidou
authors.forename: Georgia
authors.initials: G
authors.lastname: Gioula
authors.forename: Maria
authors.initials: M
authors.lastname: Exindari
authors.forename: Dimitris
authors.initials: D
authors.lastname: Chatzidimitriou
authors.forename: Eudoxia
authors.initials: E
authors.lastname: Diza
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Malisiovas
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019943:Amino Acid Substitution / Q000235:genetics; D016000:Cluster Analysis; D005260:Female; D006115:Greece; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D007251:Influenza, Human / Q000473:pathology* / Q000821:virology*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D010802:Phylogeny; D011110:Polymorphism, Genetic; D012367:RNA, Viral / Q000235:genetics; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D012720:Severity of Illness Index; D037521:Virulence Factors / Q000235:genetics*; D055815:Young Adult
chemical_list: C543345:H1N1 virus hemagglutinin; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D012367:RNA, Viral; D037521:Virulence Factors