Bordetella pertussis infection in household contacts of cases of pertussis in the southeast zone of the city of Cali, Colombia, 2006-2007

Abstract

Introduction: Bordetella pertussis causes whooping cough or convulsive cough, a contagious and immune-preventable disease. It is one of the 10 leading causes of death among children younger than one year of age, when not completely immunized. It is considered reemerging in several countries, with high rates of complications and hospitalizations. Objective: to learn of the proportion of infection by B. pertussis among suspected cases of whooping cough and their household contacts among children from the southeast zone of Cali, a geographic area with great consultation demand due to this infection. Methodology: This is a cross-sectional descriptive study. Epidemiological data and nasopharyngeal samples were taken from 24 suspected cases and from their 109 household contacts. The samples were analyzed via real-time polymerase chain reaction (Q-PCR) and through culture. Results: The proportion of positivity among the cases via the Q-PCR technique was at 50% (12/24) and at 40% via the culture technique (8/20), with good agreement between both techniques (Kappa 0.61). Regarding the household contacts, 30.3% (33/109) (CI 95%: 21.8%-39.8%) tested positive. The sibling contacts (7/15) and the mothers (7/22) presented the greatest proportion of positivity. Regarding age, 60% were 4 years of age (3/5) and 50% were in the group comprised of individuals 45 to 64 years of age. No significant differences were found among the presence or absence of symptoms and the presence of B. pertussis infection, except for the presence of nasal secretions (runny nose) (27%) and coughing (36%) during the last month. Conclusions: The study confirms the high prevalence of asymptomatic infection by B. pertussis among household contacts of children with whooping cough symptomatology and its household transmission. In Cali, health authorities need to review the effectiveness of implemented control strategies and the use of a vaccination scheme that does not cover adolescent and adult populations as a focus of infection control.

The burden of laboratory-confirmed pertussis in low- and middle-income countries since the inception of the Expanded Programme on Immunisation (EPI) in 1974: a systematic review and meta-analysis

“…In contrast, culture, recognised as the diagnostic gold standard, missed on average 85% of cases identified by PCR in the studies that used both methods in this systematic review. Higher culture prevalence estimates than in other Mortality and case fatality rate of confirmed pertussis studies in a similar WHO group were noted when the studies were conducted before a vaccination programme was fully established (Voorhoeve et al), during an outbreak (Cooper and Fitch [79]; Strebel et al; and Al-Bargish) and when the study included secondary attack data of close contacts (Astudillo et al) [26,28,41,83].…”