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. 2013 Aug;17(8):1049-55.
doi: 10.5588/ijtld.12.0933.

Yield of contact tracing from pediatric tuberculosis index cases in Gaborone, Botswana

S Puryear  1 , G Seropola, A Ho-Foster, T Arscott-Mills, L Mazhani, J Firth, D M Goldfarb, R Ncube, G P Bisson, A P Steenhoff
Affiliations

Yield of contact tracing from pediatric tuberculosis index cases in Gaborone, Botswana

S Puryear et al. Int J Tuberc Lung Dis. 2013 Aug.

Abstract
in English, French, Spanish

Setting: Contact tracing using pediatric index cases has not been adequately investigated in high tuberculosis (TB) and human immunodeficiency virus (HIV) prevalence settings.

Objective: To determine the yield of contact tracing in household contacts of pediatric TB index cases in Botswana.

Design: Index cases included all pediatric (age ≤ 13 years) TB admissions from January 2009 to December 2011 to Botswana's largest referral hospital. A contact tracing team identified cases, conducted home visits, symptom-screened contacts and referred those with ≥ 1 TB symptoms. The primary outcome was newly diagnosed TB in a contact.

Results: From 163 pediatric index cases, 548 contacts were screened (median 3 contacts/case, interquartile range [IQR] 2-4). Of these, 49 (9%) were referred for positive symptoms on screening and 27/49 (55%) were evaluated for active TB. Twelve new TB cases were diagnosed (12/548, 2.2%); the median age was 31 years (IQR 23-38); 11 (92%) were smear-positive. Ten (83%) had known HIV status: 7 (70%) were HIV-positive. To find one new TB case, the number needed to contact trace (index cases/new cases) was 13.6, and the number needed to screen (contacts/new cases) was 46.

Conclusion: This yield of contact tracing using pediatric index cases is similar to the traditional adult index case approach. Improving the proportion of symptomatic contacts evaluated may increase yield.

CONTEXTE :: Dans les contextes à haute prévalence du virus de l’immunodéficience humaine (VIH) et tuberculose (TB), la recherche des contacts à partir des cas-index pédiatriques n’a pas été investiguée adéquatement.

OBJECTIF: Déterminer au Botswana le rendement de la recherche des contacts chez les sujets en contact dans le ménage avec des cas index pédiatriques atteints de TB.

SCHÉMA: Les cas-index ont correspondu à l’ensemble de toutes les admissions TB pédiatriques (⩽13 ans) de janvier 2009 à décembre 2011 dans le plus grand hôpital de référence du Botswana. Une équipe de recherche des contacts a identifié les cas, mené des visites à domicile, dépisté les contacts sur base des symptômes et référé ceux accusant au moins un symptôme TB. Le résultat principal a été une TB nouvellement diagnostiquée chez un contact.

RÉSULTATS: A partir de 163 cas-index pédiatriques, on a dépisté 548 contacts (valeur médiane 3 contacts/cas, extrêmes interquartiles [IQR] 2–4). Parmi ceux-ci, 49 (9%) ont été référés en raison d’un dépistage positif des symptômes et 27/49 (55%) ont été évalués à la recherche d’une TB active. On a diagnostiqué 12 nouveaux cas de TB (12/548, 2,2%; âge médian 31 ans, IQR 23–38). Il y a eu 11 cas à frottis positif (92%). Dans 10 cas (83%), le statut VIH était connu : 7 (70%) étaient séropositifs pour le VIH. Pour trouver un nouveau cas TB, le nombre de cas-index nécessaires à rechercher (cas index/ nouveaux cas) a été de 13,6. Le nombre de cas-contact qu’il fallait dépister (contacts/nouveaux cas) a été de 46.

CONCLUSION: Ce rendement des recherches des contacts à partir des cas-index pédiatriques est similaire à celui de l’approche traditionnelle des cas-index adultes. Une augmentation de la proportion des contacts symptomatiques évalués pourrait augmenter ce rendement.

MARCO DE REFERENCIA: La investigación de contactos a partir de los casos nuevos pediátricos no se ha investigado adecuadamente en los entornos con alta prevalencia de coinfección por el virus de la inmunodeficiencia humana (VIH) y tuberculosis (TB).

OBJETIVO:: Determinar el rendimiento de la investigación de los contactos domésticos de los casos nuevos pediátricos en Botsuana.

MÉTODO: Los casos nuevos consistieron en todos los pacientes pediátricos (hasta los 13 años de edad) hospitalizados por TB entre enero del 2009 y diciembre del 2011 en el principal hospital de referencia de Botsuana. Un equipo de seguimiento de contactos detectó los casos, practicó las visitas domiciliarias, la detección de los síntomas en los hogares y remitió a las personas con uno o más síntomas indicativos de TB. El criterio primario de evaluación fue el diagnóstico de un caso nuevo de TB en uno de los contactos investigados.

RESULTADOS: Se investigaron 548 contactos de 163 casos nuevos pediátricos (una mediana de tres contactos por caso nuevo, intervalo intercuartil [IQR] 2–4). De estos contactos, se remitieron 49 (9%) por una detección positiva de síntomas y en 27 de los 49 (55%) se investigó la TB activa. Se diagnosticaron 12 casos nuevos de TB (12/548 contactos; 2,2%; edad mediana 31 años, IQR 23–38); 11 casos (92%) tuvieron baciloscopias positivas. Diez personas (83%) conocían su situación frente al VIH y siete eran seropositivas (70%). A fin de detectar un caso nuevo de TB fue necesario practicar la investigación de los contactos de 13,6 casos iniciales (casos iniciales/casos nuevos); se debió practicar la detección sistemática de 46 personas (contactos/casos nuevos).

CONCLUSIÓN: Este rendimiento de la investigación de contactos de los casos nuevos pediátricos es equivalente al rendimiento de la estrategia convencional en los adultos. Se podría mejorar el rendimiento al aumentar la proporción de casos sintomáticos evaluados.

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Conflict of interest statement

Conflict of interest: none declared.

Figures

Figure 1
Figure 1
Contact tracing procedure. *Defined as any household contact with one or more of the following: cough of any duration, presence of sputum, weight loss. TB = tuberculosis; IPT = isoniazid preventive therapy.
Figure 2
Figure 2
Study flow diagram. * Defined as any household contact with one or more of the following: cough of any duration, presence of sputum, weight loss. † Consisting of a clinical history and examination as well as sputum smear, chest radiography, tuberculin skin test, and/or sputum culture as determined by a clinic nurse or doctor. TB = tuberculosis.
Figure 3
Figure 3
One-way sensitivity analysis of TB prevalence among non-evaluated, symptomatic contacts to determine adjusted TB case yields. ‘Baseline yield’ refers to the TB prevalence detected and reported among contacts in this study; ‘44.4% TB prevalence’ assumes the same TB prevalence among symptomatic contacts who were not evaluated and contacts who were; ‘100% TB prevalence’ assumes 100% TB prevalence among symptomatic contacts who were not evaluated.
See this image and copyright information in PMC

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