title: Isolation and characterization of influenza C viruses in the Philippines and Japan.
abstract: From November 2009 to December 2013 in the Philippines, 15 influenza C viruses were isolated, using MDCK cells, from specimens obtained from children with severe pneumonia and influenza-like illness (ILI). This is the first report of influenza C virus isolation in the Philippines. In addition, from January 2008 to December 2013, 7 influenza C viruses were isolated from specimens that were obtained from children with acute respiratory illness (ARI) in Sendai city, Japan. Antigenic analysis with monoclonal antibodies to the hemagglutinin-esterase (HE) glycoprotein showed that 19 strains (12 from the Philippines and 7 from Japan) were similar to the influenza C virus reference strain C/Sao Paulo/378/82 (SP82). Phylogenetic analysis of the HE gene showed that the strains from the Philippines and Japan formed distinct clusters within an SP82-related lineage. The clusters that included the Philippine and Japanese strains were shown to have diverged from a common ancestor around 1993. In addition, phylogenetic analysis of the internal genes showed that all strains isolated in the Philippines and Japan had emerged through reassortment events. The composition of the internal genes of the Philippine strains was different from that of the Japanese strains, although all strains were classified into an SP82-related lineage by HE gene sequence analysis. These observations suggest that the influenza C viruses analyzed here had emerged through different reassortment events; however, the time and place at which the reassortment events occurred were not determined.
authors.affiliation: Department of Virology, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Miyagi, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Odagiri
authors.affiliation: Department of Infectious Diseases, Yamagata University Faculty of Medicine, Iida-Nishi, Yamagata, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Matsuzaki
authors.affiliation: Department of Virology, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Miyagi, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Okamoto
authors.affiliation: Department of Virology, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Miyagi, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Suzuki
authors.affiliation: Department of Virology, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Miyagi, Japan RITM-Tohoku Research Collaborating Center for Emerging and Reemerging Diseases, Muntinlupa City, Philippines.
authors.forename: Mariko
authors.initials: M
authors.lastname: Saito
authors.affiliation: Department of Virology, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Miyagi, Japan RITM-Tohoku Research Collaborating Center for Emerging and Reemerging Diseases, Muntinlupa City, Philippines.
authors.forename: Raita
authors.initials: R
authors.lastname: Tamaki
authors.affiliation: Research Institute for Tropical Medicine, Muntinlupa City, Philippines.
authors.forename: Socorro P
authors.initials: SP
authors.lastname: Lupisan
authors.affiliation: Research Institute for Tropical Medicine, Muntinlupa City, Philippines.
authors.forename: Lydia T
authors.initials: LT
authors.lastname: Sombrero
authors.affiliation: Department of Infectious Diseases, Yamagata University Faculty of Medicine, Iida-Nishi, Yamagata, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Hongo
authors.affiliation: Department of Virology, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Miyagi, Japan oshitanih@med.tohoku.ac.jp.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Oshitani
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D019143:Evolution, Molecular; D005260:Female; D014644:Genetic Variation; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007251:Influenza, Human / Q000821:virology*; D009982:Gammainfluenzavirus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D007564:Japan; D008297:Male; D008969:Molecular Sequence Data; D010679:Philippines; D010802:Phylogeny; D011446:Prospective Studies; D016865:Reassortant Viruses / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D017422:Sequence Analysis, DNA
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus