Prevalence of tuberculosis in Rwanda: Results of the first nationwide survey in 2012 yielded important lessons for TB control

Abstract

Background Rwanda conducted a national tuberculosis (TB) prevalence survey to determine the magnitude of TB in the country and determine to what extent the national surveillance system captures all TB cases. In addition we measured the patient diagnostic rate, comparing the measured TB burden data with the routine surveillance data to gain insight into how well key population groups are being detected. Methods A national representative nationwide cross-sectional survey was conducted in 73 clusters in 2012 whereby all enrolled participants (residents aged 15 years and above) were systematically screened for TB by symptoms and chest X-ray (CXR). Those with either clinical symptoms (cough of any duration) and/or CXR abnormalities suggestive of TB disease were requested to provide two sputum samples (one spot and one morning) for smear examination and solid culture. Results Of the 45,058 eligible participants, 43,779 were enrolled in the survey. Participation rate was high at 95.7% with 99.8% of participants undergoing both screening procedures and 99.0% of those eligible for sputum examination submitting at least one sputum sample. Forty cases of prevalent mycobacterium tuberculosis (MTB) and 16 mycobacteria other than tuberculosis (MOTT) cases were detected during the survey. Chest x-ray as screening tool had 3 and 5 times greater predictive odds for smear positive and bacteriological confirmed TB than symptom screening alone respectively. A TB prevalence of 74.1 (95% CI 48.3-99.3) per 100,000 adult population for smear positive TB and 119.3 (95% CI 78.8-PLOS ONE

Prevalence ofMycobacterium tuberculosisin Sputum and Reported Symptoms Among Clinic Attendees Compared With a Community Survey in Rural South Africa

“…Our community survey screening methods are comparable to other surveys [22,23,30,31], but our estimate is based on a single sputum specimen. National TB prevalence survey estimates are based on 2 specimens and our estimate is therefore likely to underestimate prevalence compared with the national survey and other surveys in which multiple samples are collected.…”

“…In the same way, our prevalence findings could be an overestimate if people who were ill were more likely to participate in the community survey, but this would not explain the high number of participants with culture-positive sputum who were asymptomatic at enrollment. Chest radiography is the most sensitive TB screening method currently available [22,23,31,34] and has the potential to substantially increase the yield of case finding in high-prevalence settings [35]. Although costly, digital chest radiography in combination with computer-aided detection software is a promising alternative in settings where limited human resources are a barrier to implementation [36].…”

National tuberculosis prevalence surveys in Africa, 2008–2016: an overview of results and lessons learned

“…diabetes, smoking) or bovine TB were excluded. Of 162 published papers, only seven were of relevance [18–24]. Grey literature, such as unpublished survey reports produced by national TB programmes, abstracts and presentations from international meetings, and routine progress updates collated by the WHO Global Task Force on TB Impact Measurement on the status of surveys since 2008, was also systematically reviewed [25–36].…”

The potential impact of novel tuberculosis vaccines on health equity and financial protection in low- and middle-income countries

“…Nationally-representative TB prevalence surveys conducted in high-burden countries have consistently demonstrated higher disease burden among poorer individuals, with TB prevalence in the lowest income quintile on average 2·3 times greater than estimated for the highest income quintile. 5-7…”

“…Nationally-representative TB prevalence surveys conducted in high-burden countries have consistently demonstrated higher disease burden among poorer individuals, with TB prevalence in the lowest income quintile on average 2•3 times greater than estimated for the highest income quintile. [5][6][7] In addition to the individual health effects, TB can have major economic consequences, especially for poor households. 8 Individuals sick with TB may be less able to work, resulting in income losses.…”