The prevalence of pulmonary tuberculosis among miners from the Karonga, Rumphi, Kasungu and Lilongwe Districts of Malawi in 2019

Introduction

Miners in sub-Saharan Africa have a greater risk of tuberculosis (TB) than any other working population in the world. In spite of the presence of large and vulnerable population of miners in Malawi, no previous study has aimed to assess the burden of TB among these miners. This study aimed to determine the prevalence of pulmonary tuberculosis (PTB) and health-seeking behaviour (HSB) in a population of miners in Malawi, and a range of associated factors. Our goal was to develop a method to identify missing cases of TB.

Methods

We conducted a cross-sectional study in the Karonga, Rumphi, Kasungu and Lilongwe districts of Malawi in 2019. We calculated frequencies, proportions, odds ratios (ORs) and their 95% confidence intervals (95% CIs), and used the chi-square test in STATA version15.1 to investigate the burden and magnitude of PTB in the mining sector. Bivariate and multivariate logistic regression models were also fitted for PTB and HSB.

Results

Of the 2400 miners approached, we were able to interview 2013 (84%). Of these, 1435 (71%) were males, 1438 (71%) had known HIV status and 272 (14%) had PTB. Multivariate analysis showed that the miners performing informal mining were 50% more likely to develop PTB compared with those in formal mining (adjusted odds ratio [AOR]=1.50, 95% CI: 1.10–2.05, P=0.01). A total of 459 (23% of 2013) miners had presumptive TB. Of these, 120 (26%) sought health care; 80% sought health care at health facilities. Multivariate analysis also showed that miners who experienced night sweats were less likely to seek health care compared with those without night sweats (AOR=0.52, 95% CI: 0.30–0.90, P=0.02).

Conclusion

The prevalence of PTB was higher among miners than in the general population. Consequently, targeted TB screening programmes for miners may represent a suitable strategy to adopt if we are to end TB by 2030. Poor health-seeking behaviours among miners is worrisome and further qualitative research is necessary to understand the barriers to accessing health care in these settings.

Drug resistance of Mycobacterium tuberculosis in Malawi: a cross-sectional survey

Objective

To document the prevalence of multidrug resistance among people newly diagnosed with – and those retreated for – tuberculosis in Malawi.

Methods

We conducted a nationally representative survey of people with sputum-smear-positive tuberculosis between 2010 and 2011. For all consenting participants, we collected demographic and clinical data, two sputum samples and tested for human immunodeficiency virus (HIV).The samples underwent resistance testing at the Central Reference Laboratory in Lilongwe, Malawi. All Mycobacterium tuberculosis isolates found to be multidrug-resistant were retested for resistance to first-line drugs – and tested for resistance to second-line drugs – at a Supranational Tuberculosis Reference Laboratory in South Africa.

Findings

Overall, M. tuberculosis was isolated from 1777 (83.8%) of the 2120 smear-positive tuberculosis patients. Multidrug resistance was identified in five (0.4%) of 1196 isolates from new cases and 28 (4.8%) of 581 isolates from people undergoing retreatment. Of the 31 isolates from retreatment cases who had previously failed treatment, nine (29.0%) showed multidrug resistance. Although resistance to second-line drugs was found, no cases of extensive drug-resistant tuberculosis were detected. HIV testing of people from whom M. tuberculosis isolates were obtained showed that 577 (48.2%) of people newly diagnosed and 386 (66.4%) of people undergoing retreatment were positive.

Conclusion

The prevalence of multidrug resistance among people with smear-positive tuberculosis was low for sub-Saharan Africa – probably reflecting the strength of Malawi’s tuberculosis control programme. The relatively high prevalence of such resistance observed among those with previous treatment failure may highlight a need for a change in the national policy for retreating this subgroup of people with tuberculosis.