Clinical features of children infected with different strains of influenza B in southern Taiwan

Pediatr Infect Dis J. 2008 Jul;27(7):640-5. doi: 10.1097/INF.0b013e31816be008.

Abstract

Background: This study was designed to determine the clinical characteristics of children infected with different strains of influenza B viruses isolated in southern Taiwan. The clinical features were compared with influenza A infection occurring in the same period.

Methods: All children enrolled in the study had laboratory-confirmed infection with influenza A or B viruses. Influenza B speciation was performed by RNA extraction, cDNA synthesis, and amplification by polymerase chain reaction and sequencing. Demographic data, clinical findings, diagnoses, and outcomes were obtained.

Results: During the study period, 163 strains of influenza A and 118 strains of influenza B were isolated. The Yamagata-like strains were most prevalent in 2001. New reassortant strains were identified since 2002 and became predominant in 2005 and 2006. Children with influenza B were more likely than those with influenza A to be diagnosed as upper respiratory tract infection, myositis, and gastroenteritis (P < 0.05). Children infected with Yamagata-like strains were more likely to develop lower respiratory tract infection (P < 0.05) and accounted for all cases of invasive disease. Children infected with the Victoria-like group had the longest hospital stays associated with severe bacterial superinfection.

Conclusions: Currently new reassortant influenza B viruses are the predominant strains circulating in southern Taiwan. There is considerable similarity of clinical features between influenza A and B in children. The Yamagata-like strains were associated with more invasive infections. Continuous influenza virus surveillance is essential particularly in Taiwan where pandemic strains tend to appear earlier than in other countries.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Child
  • Child, Preschool
  • DNA, Complementary / genetics
  • DNA, Complementary / isolation & purification
  • Female
  • Humans
  • Infant
  • Influenza A virus / classification
  • Influenza A virus / genetics
  • Influenza A virus / isolation & purification
  • Influenza B virus / classification
  • Influenza B virus / genetics
  • Influenza B virus / isolation & purification*
  • Influenza, Human / physiopathology*
  • Influenza, Human / virology*
  • Length of Stay
  • Male
  • Pneumonia / epidemiology
  • Pneumonia / virology
  • Polymerase Chain Reaction
  • RNA, Viral / genetics
  • RNA, Viral / isolation & purification
  • Reassortant Viruses / classification
  • Reassortant Viruses / genetics
  • Reassortant Viruses / isolation & purification
  • Respiratory Tract Infections / epidemiology
  • Respiratory Tract Infections / virology
  • Sequence Analysis, DNA
  • Taiwan / epidemiology

Substances

  • DNA, Complementary
  • RNA, Viral