title: [Analysis on the aetiology of influenza in children in Tianjin].
abstract: OBJECTIVE
  To analyse the pathogen of child patients with influenza in Tianjin area.
  
  
  METHODS
  The influenza virus isolation was performed by MDCK cells and embryonated eggs. The identification of the isolates was carried out with hemagglutination (HA) and hemagglutination inhibition (HI) tests.
  
  
  RESULTS
  Two hundred and thirty-eight throat swab specimens from children with influenza-like illness were collected in Tianjin area from Oct. 2001 to Mar. 2002 and 64 strains (26.9%) of influenza virus were isolated. Data showed that there were 42 strains (65.6%) of A (H3N2) subtype, 13 strains (20.3%) of A (H1N1) subtype and 9 strains (14.1%) of B type in these positive isolates. All the isolated viruses grew very well in MDCK cells and hemagglutinated with human "O" red blood cells, and most (62/64 strains) of them were able to multiply in embryonated chick eggs. However, there were only 3 isolates with HA positive in inoculating embryonated eggs with the specimens. Meanwhile, it was revealed that out of 55 strains of A type viruses, 53 strains (96.4%) were from O to D phase, 2 strain of A (H3N2) were D phase characters and all B type isolated viruses being D phase properties.
  
  
  CONCLUSIONS
  There were three endemic types of influenza viruses-A (H3N2), A (H1N1) and B type in Tianjin area, with A, the main type.
authors.affiliation: Tianjin Centers for Disease Control and Prevention, Tianjin 300011, China.
authors.forename: Xiao-hua
authors.initials: XH
authors.lastname: Guo
authors.forename: Wei-ping
authors.initials: WP
authors.lastname: Duan
authors.forename: Shi-rong
authors.initials: SR
authors.lastname: Wang
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Jin-ying
authors.initials: JY
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D005260:Female; D014644:Genetic Variation; D006385:Hemagglutination Inhibition Tests; D006386:Hemagglutination Tests; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D009980:Influenza A virus / Q000145:classification / Q000302:isolation & purification*; D009981:Influenza B virus / Q000145:classification / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology / Q000209:etiology* / Q000821:virology*; D008297:Male