Dataset Information

Incident Mycobacterium tuberculosis infection in household contacts of infectious tuberculosis patients in Brazil.

ABSTRACT:

Background

In household contact investigations of tuberculosis (TB), a second tuberculin skin test (TST) obtained several weeks after a first negative result consistently identifies individuals that undergo TST conversion. It remains unclear whether this delay in M. tuberculosis infection is related to differences in the infectious exposure, TST boosting, partial host resistance, or some other factor.

Methods

We conducted a household contact study Vitória, Brazil. Between 2008 and 2013, we identified culture-positive pulmonary TB patients and evaluated their household contacts with both a TST and interferon gamma release assay (IGRA), and identified TST converters at 8-12 weeks post study enrollment. Contacts were classified as TST-positive (?10 mm) at baseline, TST converters, or persistently TST-negative. We compared TST converters to TST-positive and to TST-negative contacts separately, using generalized estimating equations.

Results

We enrolled 160 index patients and 838 contacts; 523 (62.4%) were TST+, 62 (7.4%) TST converters, and 253 (30.2%) TST-. TST converters were frequently IGRA- at 8-12 weeks. In adjusted analyses, characteristics distinguishing TST converters from TST+ contacts (no contact with another TB patient and residence ownership) were different than those differentiating them from TST- contacts (stronger cough in index patient and contact BCG scar).

Conclusions

The individual risk and timing of M. tuberculosis infection within households is variable and dependent on index patient, contact and environmental factors within the household, and the surrounding community. Our findings suggest a threshold effect in the risk of infection in humans.

SUBMITTER: Jones-Lopez EC

PROVIDER: S-EPMC5563014 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature

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Publications

Incident Mycobacterium tuberculosis infection in household contacts of infectious tuberculosis patients in Brazil.

Jones-López Edward C EC Acuña-Villaorduña Carlos C Fregona Geisa G Marques-Rodrigues Patricia P White Laura F LF Hadad David Jamil DJ Dutra-Molina Lucilia Pereira LP Vinhas Solange S McIntosh Avery I AI Gaeddert Mary M Ribeiro-Rodrigues Rodrigo R Salgame Padmini P Palaci Moises M Alland David D Ellner Jerrold J JJ Dietze Reynaldo R

BMC infectious diseases 20170818 1

<h4>Background</h4>In household contact investigations of tuberculosis (TB), a second tuberculin skin test (TST) obtained several weeks after a first negative result consistently identifies individuals that undergo TST conversion. It remains unclear whether this delay in M. tuberculosis infection is related to differences in the infectious exposure, TST boosting, partial host resistance, or some other factor.<h4>Methods</h4>We conducted a household contact study Vitória, Brazil. Between 2008 and ...[more]

PMID: 28821234

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Project description:BackgroundThe End TB Strategy calls for systematic screening of selected high-risk groups including contacts of tuberculosis (TB) cases to facilitate early TB case detection. Contact investigation is not usually routinely practiced in low TB burden countries, such as Ghana, with consequent paucity of data on the yield of TB case detection from such interventions. This study's objective was to document the outcomes and feasibility of implementing contact investigation activities under programmatic conditions in Ghana.MethodsRetrospective analyses were conducted of abstracted data from the National TB Program, following a contact investigation intervention for TB cases diagnosed in 10 facilities in Accra from June 2010 to December 2014. Various proportions and yield from number of contacts needed to screen (NNS) and number needed to test (NNT) to detect a TB case were assessed.ResultsOverall, out of the 8519 listed contacts of 3267 index cases, 8166 (96%) were screened and 614 (7.5%) were identified as presumptive TB. Out of these, 438 (71%) underwent sputum smear microscopy/evaluation and 53 TB cases were diagnosed. Of these, 56.6% were males, and 49% had sputum smear-positive TB, 38% had sputum smear-negative TB, and 7% had extra-pulmonary TB. The NNS and NNT to detect a TB case of all forms were 154 and 8, respectively. The proportion of TB cases with contacts listed and proportion of contacts screened annually were 88-96% and 83-100%, respectively. The proportion of presumptive TB cases tested and proportion of TB cases diagnosed among contacts tested that were 100% and 36%, respectively, in 2010 dropped to 40% and 14%, respectively, by 2014.ConclusionsThe study demonstrates that contact identification and prioritization components of a contact investigation were feasible, but overall yield of TB cases may have been lower due to the declining rate of clinical evaluation of presumptive TB contacts over time. Addressing barriers to accessing appropriate diagnostic tests may enhance yield from contact investigation in Ghana.

Dataset Information

Incident Mycobacterium tuberculosis infection in household contacts of infectious tuberculosis patients in Brazil.

Background

Methods

Results

Conclusions

Publications

Incident Mycobacterium tuberculosis infection in household contacts of infectious tuberculosis patients in Brazil.

Similar Datasets

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