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. 2017 Jun 5;12(6):e0178873.
doi: 10.1371/journal.pone.0178873. eCollection 2017.

School and household tuberculosis contact investigations in Swaziland: Active TB case finding in a high HIV/TB burden setting

Piluca Alonzo Ustero  1 , Alexander W Kay  1 , Katherine Ngo  1 , Rachel Golin  1 , Bhekisisa Tsabedze  1   2 , Bulisile Mzileni  1   2 , Jessica Glickman  1 , Mildred Wisile Xaba  3 , Gcinile Mavimbela  4 , Anna Maria Mandalakas  1
Affiliations

School and household tuberculosis contact investigations in Swaziland: Active TB case finding in a high HIV/TB burden setting

Piluca Alonzo Ustero et al. PLoS One. .

Abstract

Background: Investigation of household contacts exposed to infectious tuberculosis (TB) is widely recommended by international guidelines to identify secondary cases of TB and limit spread. There is little data to guide the use of contact investigations outside of the household, despite strong evidence that most TB infections occur outside of the home in TB high burden settings. In older adolescents, the majority of infections are estimated to occur in school. Therefore, as part of a project to increase active case finding in Swaziland, we performed school contact investigations following the identification of a student with infectious TB.

Methods: The Butimba Project identified 7 adolescent TB index cases (age 10-20) with microbiologically confirmed disease attending 6 different schools between June 2014 and March 2015. In addition to household contact investigations, Butimba Project staff worked with the Swaziland School Health Programme (SHP) to perform school contact investigations. At 6 school TB screening events, between May and October 2015, selected students underwent voluntary TB screening and those with positive symptom screens provided sputum for TB testing.

Results: Among 2015 student contacts tested, 177 (9%) screened positive for TB symptoms, 132 (75%) produced a sputum sample, of which zero tested positive for TB. Household contact investigations of the same index cases yielded 40 contacts; 24 (60%) screened positive for symptoms; 19 produced a sputum sample, of which one case was confirmed positive for TB. The odds ratio of developing TB following household vs. school contact exposure was significantly lower (OR 0.0, 95% CI 0.0 to 0.18, P = 0.02) after exposure in school.

Conclusion: School-based contact investigations require further research to establish best practices in TB high burden settings. In this case, a symptom-based screening approach did not identify additional cases of tuberculosis. In comparison, household contact investigations yielded a higher percentage of contacts with positive TB screens and an additional tuberculosis case.

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Conflict of interest statement

Competing Interests: This project was supported by the TB REACH Initiative of the Stop TB Partnership (through a grant from Global Affairs Canada). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The primary grant recipient was the Baylor College of Medicine’s Children’s Foundation Swaziland (Program Director PAU). Mott MacDonald was contracted by the Stop TB Partnership to provide independent monitoring and evaluation of TB REACH projects. It contributed professional services and opinion independently of the funder (principally Global Affairs Canada), Stop TB Partnership and the grantee. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

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