title: Prevalence of asymptomatic Bordetella pertussis and Bordetella parapertussis infections among school children in China as determined by pooled real-time PCR: a cross-sectional study.
abstract: BACKGROUND
  Studies have documented that older children and adolescents act as a reservoir of Bordetella pertussis infection for young infants who have not yet completed their primary immunization schedule. Asymptomatic pertussis infection has been reported during outbreaks. This cross-sectional study aimed to investigate whether B. pertussis and Bordetella parapertussis can colonize the nasopharynx of healthy school children, using culture and pooled real-time PCR with targets for insertion sequences IS481 and IS1001.
  
  
  METHODS
  Nasopharyngeal (NP) swabs were taken from 629 asymptomatic school children aged 7 to 15 y in 4 counties of China during the period July-September 2011. The number of subjects included in each county ranged from 153 to 165. The 4 counties selected are located in the north, south, east, and southwest regions of China. NP swabs were inoculated onto Regan-Lowe agar for isolation of suspected Bordetella organisms. Pooled real-time PCRs were used to detect B. pertussis and B. parapertussis based on the IS481 and IS1001 targets separately.
  
  
  RESULTS
  Of the 629 subjects, 2 (0.3%) and 30 (4.8%) were confirmed to be culture-positive and PCR-positive, respectively, for B. pertussis, and 1 (0.2%) and 13 (2.1%) were confirmed to be culture-positive and PCR-positive, respectively, for B. parapertussis. All culture-positive samples were also PCR-positive. Furthermore, positive B. pertussis and B. parapertussis samples were found in all counties.
  
  
  CONCLUSIONS
  Our results indicate that asymptomatic B. pertussis infections are common in school children in China, and asymptomatic B. parapertussis infections are more prevalent than previously documented.
authors: From the National Institute for Communicable Disease Control and Prevention, State Key Laboratory for Infectious Diseases Prevention and Control, Chinese Center for Disease Control and Prevention , Beijing.
authors: Qi
authors: Q
authors: Zhang
authors: Zundong
authors: Z
authors: Yin
authors: Yixing
authors: Y
authors: Li
authors: Huiming
authors: H
authors: Luo
authors: Zhujun
authors: Z
authors: Shao
authors: Yuan
authors: Y
authors: Gao
authors: Li
authors: L
authors: Xu
authors: Biao
authors: B
authors: Kan
authors: Shan
authors: S
authors: Lu
authors: Yan
authors: Y
authors: Zhang
authors: Manshi
authors: M
authors: Li
authors: Meizhen
authors: M
authors: Liu
authors: Pingping
authors: P
authors: Yao
authors: Zhixian
authors: Z
authors: Zhao
authors: Qiushui
authors: Q
authors: He
mesh_terms: D000293:Adolescent; D058070:Asymptomatic Diseases / Q000453:epidemiology; D001885:Bordetella Infections / Q000453:epidemiology* / Q000382:microbiology*; D042483:Bordetella parapertussis / Q000235:genetics / Q000302:isolation & purification*; D001886:Bordetella pertussis / Q000235:genetics / Q000302:isolation & purification*; D002648:Child; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D006801:Humans; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods