title: Analyses of Evolutionary Characteristics of the Hemagglutinin-Esterase Gene of Influenza C Virus during a Period of 68 Years Reveals Evolutionary Patterns Different from Influenza A and B Viruses.
abstract: Infections with the influenza C virus causing respiratory symptoms are common, particularly among children. Since isolation and detection of the virus are rarely performed, compared with influenza A and B viruses, the small number of available sequences of the virus makes it difficult to analyze its evolutionary dynamics. Recently, we reported the full genome sequence of 102 strains of the virus. Here, we exploited the data to elucidate the evolutionary characteristics and phylodynamics of the virus compared with influenza A and B viruses. Along with our data, we obtained public sequence data of the hemagglutinin-esterase gene of the virus; the dataset consists of 218 unique sequences of the virus collected from 14 countries between 1947 and 2014. Informatics analyses revealed that (1) multiple lineages have been circulating globally; (2) there have been weak and infrequent selective bottlenecks; (3) the evolutionary rate is low because of weak positive selection and a low capability to induce mutations; and (4) there is no significant positive selection although a few mutations affecting its antigenicity have been induced. The unique evolutionary dynamics of the influenza C virus must be shaped by multiple factors, including virological, immunological, and epidemiological characteristics.
authors.affiliation: Department of Virology, Tohoku University Graduate School of Medicine, Sendai 9808575, Japan. furusey.tohoku@gmail.com.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Furuse
authors.affiliation: Department of Infectious Diseases, Yamagata University Faculty of Medicine, Yamagata 9909585, Japan. matuzaki@med.id.yamagata-u.ac.jp.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Matsuzaki
authors.affiliation: Virus Research Center, Clinical Research Division, Sendai Medical Center, Sendai 9838520, Japan. hide_nishimura1955@yahoo.co.jp.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Nishimura
authors.affiliation: Department of Virology, Tohoku University Graduate School of Medicine, Sendai 9808575, Japan. oshitanih@med.tohoku.ac.jp.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Oshitani
mesh_terms: D019295:Computational Biology; D019143:Evolution, Molecular; D014943:Global Health; D006389:Hemagglutinins, Viral / Q000235:genetics*; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology / Q000821:virology; D009982:Gammainfluenzavirus / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D017720:Molecular Epidemiology; D014760:Viral Fusion Proteins / Q000235:genetics*
chemical_list: D006389:Hemagglutinins, Viral; D014760:Viral Fusion Proteins; C060814:hemagglutinin esterase
keywords: evolution; influenza C virus; phylogenetics