title: Bordetella pertussis: an underreported pathogen in pediatric respiratory infections, a prospective cohort study.
abstract: BACKGROUND
  The incidence of pertussis has been increasing worldwide. In the Netherlands, the seroprevalence has risen higher than the reported cases, suggesting that laboratory tests for pertussis are considered infrequently and that even more pertussis cases are missed. The objective of our study was to determine the frequency of pertussis in clinically unsuspect cases compared to suspect cases with the intention of finding clinical predictors.
  
  
  METHODS
  The present prospective cohort study was part of a controlled clinical trial evaluating the impact of molecular diagnostics on clinical decision making in pediatric respiratory infections, performed during 2 winter seasons. For this study, in the first season pertussis was only tested in case of clinical suspicion, in the second season, pertussis was also tested without clinical suspicion. Multivariate and univariate analysis were performed using SPSS 18 and Statistical software 'R'.
  
  
  RESULTS
  In the two seasons respectively 22/209 (10,5%) and 49/373 (13,1%) cases were clinically suspected of pertussis. Bordetella pertussis was detected by real time RT-PCR in respectively 2/22 (9,1%) and 7/49 (14,3%) cases. In the second season an additional 7 cases of pertussis were found in clinically unsuspected cases (7/257 = 2,7%). These additional cases didn't differ in clinical presentation from children without a positive test for pertussis with respect to respiratory symptoms.
  
  
  CONCLUSIONS
  Pertussis in children sometimes mimics viral respiratory tract infections. If pertussis diagnostics are based on clinical suspicion alone, about 1 in 5 cases (19%) is missed. Despite widely accepted clinical criteria, paroxysmal cough is not a good predictor of pertussis. To prevent spreading, physicians should include B. pertussis in routine diagnostics in respiratory tract infections.
authors.affiliation: Department of Pediatrics, ErasmusMC-Sophia, Wytemaweg 80 3015 CN, Rotterdam, The Netherlands. g.vandenbrink@erasmusmc.nl.
authors.forename: Gertrude
authors.initials: G
authors.lastname: van den Brink
authors.forename: Jérôme O
authors.initials: JO
authors.lastname: Wishaupt
authors.forename: Jacob C
authors.initials: JC
authors.lastname: Douma
authors.forename: Nico G
authors.initials: NG
authors.lastname: Hartwig
authors.forename: Florens G A
authors.initials: FG
authors.lastname: Versteegh
mesh_terms: D001886:Bordetella pertussis / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D010372:Pediatrics / Q000706:statistics & numerical data; D011446:Prospective Studies; D012621:Seasons; D016036:Seroepidemiologic Studies; D014917:Whooping Cough / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology