title: Genetic characterization of measles virus in the Philippines, 2008-2011.
abstract: BACKGROUND
  Large outbreaks of measles occurred in the Philippines in 2010 and 2011. Genetic analysis was performed to identify the genotype of measles virus (MeV) that was responsible for the large outbreaks.
  
  
  METHODS
  A total of 114 representative MeVs that were detected in the Philippines from 2008 to 2011 were analyzed by sequencing the C-terminal region of nucleocapsid (N) gene and partial hemagglutinin (H) gene and by inferring the phylogenetic trees.
  
  
  RESULTS
  Genetic analysis showed that genotype D9 was the predominant circulating strain during the 4-year study period. Genotype D9 was detected in 23 samples (92%) by N gene sequencing and 93 samples (94%) by H gene analysis. Sporadic cases of genotype G3 MeV were identified in 2 samples (8%) by N gene sequencing and 6 samples (6%) by H gene analysis. Genotype G3 MeV was detected mainly in Panay Island in 2009 and 2010. Molecular clock analysis of N gene showed that the recent genotype D9 viruses that caused the big outbreaks in 2010 and 2011 diverged from a common ancestor in 2005 in one of the neighboring Southeast Asian countries, where D9 was endemic. These big outbreaks of measles resulted in a spillover and were associated with genotype D9 MeV importation to Japan and the USA.
  
  
  CONCLUSIONS
  Genotype D9 MeV became endemic and caused two big outbreaks in the Philippines in 2010 and 2011. Genotype G3 MeV was detected sporadically with limited geographic distribution. This study highlights the importance of genetic analysis not only in helping with the assessment of measles elimination program in the country but also in elucidating the transmission dynamics of measles virus.
authors.affiliation: Research Institute for Tropical Medicine (RITM), Alabang, Muntinlupa City, Philippines. rexcenteno@yahoo.com.
authors.forename: Rex
authors.initials: R
authors.lastname: Centeno
authors.affiliation: Department of Virology, Graduate School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi Prefecture, 980-8575, Japan. n-fuji@nibio.go.jp.
authors.forename: Naoko
authors.initials: N
authors.lastname: Fuji
authors.affiliation: Department of Virology, Graduate School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi Prefecture, 980-8575, Japan. okamotom@med.tohoku.ac.jp.
authors.forename: Michiko
authors.initials: M
authors.lastname: Okamoto
authors.affiliation: Department of Virology, Graduate School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi Prefecture, 980-8575, Japan. clyde@med.tohoku.ac.jp.
authors.forename: Clyde
authors.initials: C
authors.lastname: Dapat
authors.affiliation: Department of Virology, Graduate School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi Prefecture, 980-8575, Japan. saitom@med.tohoku.ac.jp.|Tohoku-RITM Collaborating Research Center for Emerging and Reemerging Infectious Diseases, Alabang, Muntinlupa City, Philippines. saitom@med.tohoku.ac.jp.
authors.forename: Mariko
authors.initials: M
authors.lastname: Saito
authors.affiliation: Research Institute for Tropical Medicine (RITM), Alabang, Muntinlupa City, Philippines. amado.tandocMD@gmail.com.
authors.forename: Amado
authors.initials: A
authors.lastname: Tandoc
authors.affiliation: Research Institute for Tropical Medicine (RITM), Alabang, Muntinlupa City, Philippines. socorrolupisan@yahoo.com.
authors.forename: Socorro
authors.initials: S
authors.lastname: Lupisan
authors.affiliation: Department of Virology, Graduate School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi Prefecture, 980-8575, Japan. oshitanih@med.tohoku.ac.jp.|Tohoku-RITM Collaborating Research Center for Emerging and Reemerging Infectious Diseases, Alabang, Muntinlupa City, Philippines. oshitanih@med.tohoku.ac.jp.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Oshitani
mesh_terms: D004279:DNA, Viral / Q000235:genetics*; D004196:Disease Outbreaks; D019143:Evolution, Molecular; D005838:Genotype; D006389:Hemagglutinins, Viral / Q000235:genetics*; D006801:Humans; D008457:Measles / Q000175:diagnosis / Q000453:epidemiology / Q000635:transmission / Q000821:virology*; D008459:Measles virus / Q000235:genetics* / Q000472:pathogenicity; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins / Q000235:genetics*; D010641:Phenotype; D010679:Philippines / Q000453:epidemiology; D010802:Phylogeny; D017422:Sequence Analysis, DNA
chemical_list: D004279:DNA, Viral; D006389:Hemagglutinins, Viral; D019590:Nucleocapsid Proteins; C032397:hemagglutinin protein G, measles virus; C000590691:measles virus nucleocapsid protein