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. 2015 Jan 26;10(1):e0117036.
doi: 10.1371/journal.pone.0117036. eCollection 2015.

Is early tuberculosis death associated with increased tuberculosis transmission?

Anu Parhar  1 , Zhiwei Gao  2 , Courtney Heffernan  1 , Rabia Ahmed  1 , Mary Lou Egedahl  1 , Richard Long  3
Affiliations

Is early tuberculosis death associated with increased tuberculosis transmission?

Anu Parhar et al. PLoS One. .

Abstract

Introduction: Tuberculosis (TB) is now a relatively uncommon disease in high income countries. As such, its diagnosis may be missed or delayed resulting in death before or shortly after the introduction of treatment. Whether early TB death is associated with increased TB transmission is unknown. To determine the transmission risk attributable to early TB death we undertook a case-control study.

Methods: All adults who were: (1) diagnosed with culture-positive pulmonary TB in the Province of Alberta, Canada between 1996 and 2012, and (2) died a TB-related death before or within the first 60 days of treatment, were identified. For each of these "cases" two sets of "controls" were randomly selected from among culture-positive pulmonary TB cases that survived beyond 60 days of treatment. "Controls" were matched by age, sex, population group, +/- smear status. Secondary cases of "cases" and "controls" were identified using conventional and molecular epidemiologic tools and compared. In addition, new infections were identified and compared in contacts of "cases" that died before treatment and contacts of their smear-matched "controls". Conditional logistic regression was used to find associations in both univariate and multivariate analysis.

Results: "Cases" were as, but not more, likely than "controls" to transmit. This was so whether transmission was measured in terms of the number of "cases" and smear-unmatched or -matched "controls" that had a secondary case, the number of secondary cases that they had or the number of new infections found in contacts of "cases" that died before treatment and their smear-matched "controls".

Conclusion: In a low TB incidence/low HIV prevalence country, pulmonary TB patients that die a TB-related death before or in the initial phase of treatment and pulmonary TB patients that survive beyond the initial phase of treatment are equally likely to transmit.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. TB Cases in Alberta from 1996–2012: Cases with Early Death and Other Outcomes.
See this image and copyright information in PMC

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References

    1. The Public Health Agency of Canada (2013) Tuberculosis in Canada 2012-Pre-release. Ottawa (Canada): Minister of Public Works and Government Services Canada.
    1. CDC (2013) Reported Tuberculosis in the United States, 2012. Atlanta, GA: U.S. Department of Health and Human Services; CDC, October.
    1. Anees Khan MA, Kovnat DM, Bachus B, Whitcomb ME, Brody JS, et al. (1977) Clinical and radiographic spectrum of pulmonary tuberculosis in the adult. Am J Med 62: 31–38. 10.1016/0002-9343(77)90346-1 - DOI - PubMed
    1. Miller WT, MacGregor RR (1978) Tuberculosis frequency of unusual radiographic findings. AJR 130: 867–875. 10.2214/ajr.130.5.867 - DOI - PubMed
    1. Naalsund A, Heldal AL, Johansen B, Kongerud J, Boe J (1994) Deaths from pulmonary tuberculosis in a low-incidence country. J Intern Med 236: 137–142. 10.1111/j.1365-2796.1994.tb01275.x - DOI - PubMed