Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Mar 21;19(1):276.
doi: 10.1186/s12879-019-3869-7.

Challenges and clinical relevance of molecular detection of Bordetella pertussis in South Africa

Fahima Moosa  1 , Mignon du Plessis  2   3 , Nicole Wolter  2   3 , Maimuna Carrim  2 , Cheryl Cohen  2   3 , Claire von Mollendorf  2   3 , Sibongile Walaza  2   3 , Stefano Tempia  2   4 , Halima Dawood  5 , Ebrahim Variava  3   6 , Anne von Gottberg  2   3
Affiliations

Challenges and clinical relevance of molecular detection of Bordetella pertussis in South Africa

Fahima Moosa et al. BMC Infect Dis. .

Abstract

Background: We assessed the utility of a multi-target, real-time PCR assay for Bordetella pertussis detection and diagnosis in patients with severe respiratory illness (SRI), influenza-like illness (ILI), and asymptomatic controls.

Methods: Real-time PCR detection of IS481, pIS1001, hIS1001 and ptxS1 was performed on nasopharyngeal specimens (SRI, ILI and controls) and induced sputum (SRI) collected from June 2012 to May 2016 through respiratory illness surveillance. Using PCR cycle threshold (Ct) value cut-offs, IS481 positive cases were classified as confirmed (Ct < 35) or possible (Ct 35-39) pertussis disease.

Results: Among 12,922 samples, 146 (1.1%) were IS481 positive of which 62% (90/146) were classified as confirmed. The attributable fraction (AF) was 92.2% (95% CI, 65.6 to 98.2%) and 90.5% (95% CI, 57.5 to 97.9%) amongst SRI and ILI PCR-confirmed pertussis cases, respectively. Amongst possible pertussis cases, AF was 36.9% (95% CI, - 142.3 to 83.6%) and 67.5% (95% CI, - 30.6 to 91.9%) in the SRI and ILI groups, respectively.

Conclusion: All IS481 positive specimens could be considered as B. pertussis infection, and potentially pertussis disease with supportive clinical information.

Keywords: Attributable fraction; Bordetella pertussis; Confirmed-pertussis; Influenza-like illness (ILI); Possible-pertussis; Real-time PCR; Severe respiratory illness; South Africa; Surveillance.

PubMed Disclaimer

Conflict of interest statement

Ethics approval and consent to participate

Ethics for SRI (M081042) and ILI (M120133) surveillance and B. pertussis testing were approved by the University of the Witwatersrand (M130260) and the University of KwaZulu Natal (BF081/12), South Africa. Written informed consent was obtained from all individuals enrolled into the study by trained surveillance officers upon interview. Surveillance officers approached adult patients directly to obtain consent. Parents, legal guardians or primary care giver were approached for cases who were minors; in addition, where a minor was old enough to understand, assent was obtained.

Consent for publication

Not applicable.

Competing interests

Halima Dawood has received honoraria/travel grants from Pfizer-South Africa, MSD329 South Africa and Mylan-South Africa. Anne von Gottberg has previously received grants from the US Centers for Disease Control and Prevention and Pfizer-South Africa. All other authors declare that they have no commercial or other association that may pose a conflict of interest.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1
Fig. 1
Flow diagram depicting breakdown of individuals enrolled, specimens collected and tested, and B. pertussis prevalence for severe respiratory (SRI) and influenza-like illness (ILI) surveillance, and controls, South Africa, June 2012 – May 2016. NP: nasopharyngeal aspirates from children < 5 years of age and combined nasopharyngeal and oropharyngeal swabs from individuals aged ≥5 years. *Confirmed = positive for B. pertussis with IS481 Ct < 35; Possible = positive for B. pertussis with IS481 35 ≥ Ct ≤ 39
Fig. 2
Fig. 2
Distribution of real-time PCR IS481 Ct values for confirmed (n = 90) and possible (n = 56) pertussis cases, by surveillance population, South Africa, June 2012 – May 2016. SRI = severe respiratory illness; ILI = influenza-like illness
See this image and copyright information in PMC

References

    1. Pertussis vaccines WHO position paper. Wkly Epidemiol Rec. 2010;85(40):385–400. - PubMed
    1. Pertussis epidemic--Washington, 2012. MMWR Morb Mortal Wkly Rep 2012 Jul;61(28):517–522. - PubMed
    1. Dalby T, Harboe ZB, Krogfelt KA. Seroprevalence of pertussis among Danish patients with cough of unknown etiology. Clin Vaccine Immunol. 2010;17(12):2016–2023. doi: 10.1128/CVI.00270-10. - DOI - PMC - PubMed
    1. Fisman DN, Tang P, Hauck T, Richardson S, Drews SJ, Low DE, et al. Pertussis resurgence in Toronto, Canada: a population-based study including test-incidence feedback modeling. BMC Public Health. 2011;11:694. doi: 10.1186/1471-2458-11-694.:694-11.. - DOI - PMC - PubMed
    1. Klein NP, Bartlett J, Fireman B, Aukes L, Buck PO, Krishnarajah G, et al. Waning protection following 5 doses of a 3-component diphtheria, tetanus, and acellular pertussis vaccine. Vaccine. 2017;35(26):3395–3400. doi: 10.1016/j.vaccine.2017.05.008. - DOI - PubMed

MeSH terms