Background and Aims Bordetella pertussis and B. parapertussis are the causative agents of whooping cough, a re-emerging infectious disease in spite of reasonable vaccination coverage. Specific diagnostic tools were applied for the first time in a Tunisian prospective study in order to get an estimation of the prevalence of Bordetella infections, and to evaluate their use to determine the epidemiological characteristics of these infections in Tunisian infants.

Methods Between 2007 and 2011, a total of 626 samples from 599 infants aged < 1 year with and without pertussoid cough were investigated for the presence of B. pertussis/parapertussis using culture and real-time PCR (RT-PCR). When possible, patients’ household contacts provided nasopharyngeal aspirates (NPAs) for RT-PCR detection of B. pertussis/parapertussis or single-serum samples for anti-PT IgG quantification.

Results All except 1 NPA were negative by conventional culture whereas PCR gave positive signals for 126 specimens (21%): B. pertussis, B. parapertussis and Bordetella spp. were detected in 82, 6 and 4% of the samples, respectively. The simultaneous presence of B. pertussis and B. parapertussis was noted in 8% of the cases. The prevalence of Bordetella infection was 20%. Most of these cases corresponded to patients younger than 6 months old who received < 3 doses of pertussis vaccine. Among the household contacts enrolled in the study, mothers were the likely source of infection in 4 cases.

Conclusions This study showed that pertussis is still prevalent in Tunisia and the disease remains a public health problem affecting not only infants but also adults.