title: Epidemiological, Clinical and Virological Characteristics of Influenza B Virus from Patients at the Hospital Tertiary Care Units in Bangkok during 2011-2014.
abstract: Influenza B virus, which causes acute respiratory infections, has increased in prevalence in recent years. Based on the nucleotide sequence of the hemagglutinin (HA) gene, influenza B virus can be divided into two lineages, Victoria and Yamagata, that co-circulate during the influenza season. However, analysis of the potential association between the clinical and virological characteristic and the lineage of influenza B viruses isolated in Thailand was lacking. To investigate influenza B virus genetically and determine its neuraminidase (NA) inhibitor susceptibility phenotype, a total of 6920 nasopharyngeal-wash samples were collected from patients with influenza-like illness between the years 2011 and 2014 and were screened for influenza B virus by real-time PCR. Of these samples, 3.1% (216/6920) were confirmed to contain influenza B viruses, and 110 of these influenza viruses were randomly selected for nucleotide sequence analysis of the HA and NA genes. Phylogenetic analysis of the HA sequences showed clustering into various clades: Yamagata clade 3 (11/110, 10%), Yamagata clade 2 (71/110, 64.5%), and Victoria clade 1 (28/110, 25.5%). The analysis of clinical characteristic demonstrated that the Victoria lineage was significantly associated with the duration of hospitalization, number of deceased cases, pneumonia, secondary bacterial infection and underlying disease. When combined with phylogenetic analysis of the NA sequences, four samples showed viruses with reassortant sequences between the Victoria and Yamagata lineages. Statistical analysis of the clinical outcomes and demographic data for the reassortant strains did not differ from those of the other strains in circulation. Oseltamivir-resistant influenza B viruses were not detected. Our findings indicated the co-circulation of the Victoria and Yamagata lineages over the past four cold seasons in Bangkok. We also demonstrated differences in the clinical symptoms between these lineages.
authors.affiliation: Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Navin
authors.initials: N
authors.lastname: Horthongkham
authors.affiliation: Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Niracha
authors.initials: N
authors.lastname: Athipanyasilp
authors.affiliation: Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Archiraya
authors.initials: A
authors.lastname: Pattama
authors.affiliation: Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Bualan
authors.initials: B
authors.lastname: Kaewnapan
authors.affiliation: Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Suthatta
authors.initials: S
authors.lastname: Sornprasert
authors.affiliation: Department of Pathology, Faculty of Medicine, Srinakharinwirot University, Bangkok, Thailand.
authors.forename: Surangrat
authors.initials: S
authors.lastname: Srisurapanont
authors.affiliation: Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Wannee
authors.initials: W
authors.lastname: Kantakamalakul
authors.affiliation: Department of Blood transfusion, Faculty of Allied Health Science, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Palanee
authors.initials: P
authors.lastname: Amaranond
authors.affiliation: Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Ruengpung
authors.initials: R
authors.lastname: Sutthent
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D004252:DNA Mutational Analysis; D005260:Female; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D009981:Influenza B virus; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology*; D008297:Male; D008875:Middle Aged; D009439:Neuraminidase / Q000037:antagonists & inhibitors / Q000235:genetics; D053139:Oseltamivir / Q000627:therapeutic use; D010641:Phenotype; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D062606:Tertiary Care Centers; D013785:Thailand; D055815:Young Adult
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D053139:Oseltamivir; D009439:Neuraminidase