Prevalence of presumptive tuberculosis cases among the population

Abstract

Introduction: Tuberculosis (TB) is still a major cause of morbidity and mortality worldwide. In Mongolia, case detection is primarily passive by direct smear examination of persons, who present to the health service with productive cough for more than 2 weeks. We conducted a representative nationwide a cross-sectional survey to estimate the TB prevalence in Mongolia in 2014–2015. The aim of this study was to assess the prevalence of presumptive TB cases and identify sensitivity and specificity of the symptom screening. Materials and methods: In the framework of the “Mongolian TB Prevalence Survey 2014-2015”, TB suspects were detected by using symptom interview screening from the 98 clusters which selected by two-staged stratified sampling. Sputum samples were taken, cultured, and smears were performed based on symptomatic and chest radiographs. Results: Of the 50,194 participants in the study, 5.1% (95% CI: 4.9–5.3) had a cough for more than 14 days. The prevalence of TB suspects in the population was 4.6% in urban areas, 6.7% in provincial centers, and 5.1% in rural soums (p <0.001). The prevalence of TB suspects was higher among males (6.5%, 95% CI: 6.1-6.8) than females (4.1%, 95% CI: 3.8-4.3) (p <0.001). The sensitivity and specificity of the symptom-based screening were20.6% (95% CI: 15.7-26.1) and 76.5% (95% CI: 75.6-77.3), respectively. Conclusion: According to the first TB prevalence survey in Mongolia, the prevalence of TB suspects was 5.1% (95% CI: 4.9-5.3). It is more common among males, and the prevalence tends to increase with age.