Children with pertussis inform the investigation of other pertussis cases among contacts

At a University Hospital in Brazil individuals that had frequent contacts with a child with confirmed pertussis (the index case) and had recent history of cough were enrolled into the study. Nasopharyngeal swabs were collected from every contact that had cough within the last 21 days. Cases confirmation followed the guidelines of the Center for Disease Control and Prevention – Atlanta, U.S.A.Pertussis diagnosis was confirmed in 51 children, (considered the index cases). Among the index cases, 72.5% (37/51) were under 6 months of age; culture for Bordetella pertussis was positive in 78.4% (40/51). Pertussis was confirmed in 39% (107/276) of the contacts of 51 index cases. Among these contacts identified as a pertussis case, 40.2% (43/107) were between 6 months and 111/2 years of age and 59.8% (64/107) were older than 111/2 years of age. Pertussis was confirmed by culture in 11.2% (12/107) of them and by epidemiologic linkage in 88.8% (95/107). Each index case allowed identifying two new cases of pertussis.Public health authorities should consider implementing early recognition of pertussis index cases and searching for pertussis cases among the contacts. Treatment of the cases and prophylaxis of the contacts is fundamental to control outbreaks in the community.Pertussis is an endemic disease, with peaks every three to four years worldwide. Incidence of pertussis has declined, however many cases of pertussis may be underreported or not diagnosed. The World Health Organization estimates that 200.000 – 400.000 deaths occur each year, most deaths occur in infants and in developing countries [1]. Pertussis in infants younger one year of age should be considers an indicator of undetected disease in the community [2].The transmissibility period of an individual with pertussis is around 21 days, but some can transmit for a longer period. Suspect cases and cases of pertussis should be isolated from young children, infants, child care centers, schools and public gatherings. Th