title: Pertussis--a re-emerging infection?
abstract: Seven cases of pertussis in patients aged between 1 and 6 months detected over 3 months were reported. Paroxysmal cough (six cases), post-tussive vomiting (three cases) and poor feeding (three cases) were the most common presenting symptoms. Bordetella pertussis was isolated from six patients. The total leucocyte counts were mildly increased (10.8-15.6x10(9)/L). The lymphocyte counts were markly raised (59-73%) and appear to be useful indicators of pertussis. It appears that herd immunity does not offer adequate protection to the vulnerable group even in well-vaccinated populations. High vaccination coverage should be maintained, and vaccination should be given as early an age as possible. Aggressive efforts to identify cases and contacts are essential. Health care workers should have a high index of suspicion for pertussis, in particular for those with paroxysmal cough and high lymphocyte counts so as to give timely diagnosis and treatment.
authors.affiliation: Department of Microbiology, Prince of Wales Hospital, Hong Kong, SAR, People's Republic of China. kittyfung@cuhk.edu.hk
authors.forename: K S C
authors.initials: KS
authors.lastname: Fung
authors.forename: W L
authors.initials: WL
authors.lastname: Yeung
authors.forename: T W
authors.initials: TW
authors.lastname: Wong
authors.forename: K W
authors.initials: KW
authors.lastname: So
authors.forename: A F B
authors.initials: AF
authors.lastname: Cheng
mesh_terms: D001886:Bordetella pertussis; D004196:Disease Outbreaks; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008297:Male; D010567:Pertussis Vaccine / Q000276:immunology / Q000627:therapeutic use; D014917:Whooping Cough / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control
chemical_list: D010567:Pertussis Vaccine