Pertussis in north-central and northwestern regions of Algeria.

Nabila Benamrouche,Chawki Kaddache,Abdelkarim Radoui,Malika Lazri,Rachida Boukari,Hassiba Tali Maamar,Kheira Rahal,Sonia Hasnaoui,Zakia Arrada,Ourida Lafer

doi:10.3855/jidc.7262

Abstract

Pertussis outbreaks continue to occur in many countries despite high vaccination coverage. Under-diagnosed cases in adolescents and adults may result in increased transmission to infants, who are at risk of severe pertussis. Additional measures to protect both groups should be considered. Nasopharyngeal samples and sera were collected from patients and household contacts with clinically suspected pertussis. Diagnoses were confirmed by culture, real-time polymerase chain reaction (PCR), and serology. Bordetella pertussis isolates were characterized by antimicrobial sensitivity and fimbrial serotyping. Of 392 participants, 134/248 patients (54%) and 66/144 contacts (45.8%) had confirmed pertussis infections. B. parapertussis was not detected. All B. pertussis isolates were sensitive to the antibiotics tested, and all expressed the Fim3, not the Fim2, fimbrial serotype. Most patients (81.2%) were <6 months (51.8% of whom were <3 months) of age; 77.6% were unvaccinated, and most positive contacts were mothers 20-40 years of age. Despite high vaccination coverage, pertussis is circulating in Algeria. Most infections occur in unvaccinated infants <6 months of age, with mothers as the main source of infection. An adolescent/adult booster should be considered. Adoption of sensitive and specific laboratory tests would improve pertussis diagnosis and surveillance.

Highlights

Pertussis outbreaks continue to occur in many countries despite high vaccination coverage
The majority of Nasopharyngeal aspirates (NPAs) (n=196) were collected from 1– 2 weeks after the onset of clinical symptoms, and the remaining specimens were obtained at 3–5 weeks (n=34) and 6–16 weeks (n=15)
Realtime polymerase chain reaction (PCR) targeted IS481 in 362 of the NPAs and nasopharyngeal swabs (NPSs); IS1001 was targeted in 264 samples

Summary

Introduction

Pertussis outbreaks continue to occur in many countries despite high vaccination coverage. Under-diagnosed cases in adolescents and adults may result in increased transmission to infants, who are at risk of severe pertussis. Bordetella pertussis isolates were characterized by antimicrobial sensitivity and fimbrial serotyping. Conclusions: Despite high vaccination coverage, pertussis is circulating in Algeria. Adolescents and adults are the most likely source of infections that occur in infants and newborns [1,2]. Despite decades of ongoing high vaccination coverage, pertussis outbreaks have been reported in many countries in the past 10 years [3,4]. Waning vaccine-induced immunity in adolescents and adults and genetic changes in circulating B. pertussis strains have been implicated in the resurgence of pertussis. The availability and use of increasingly more sensitive diagnostic tests may have contributed to an increase in the number of reported pertussis outbreaks [4,5]

Methods

Results

Discussion

Conclusion