Abstract
BackgroundTuberculosis remains a serious public health concern globally. The enormous social, economic, and health impacts of the diseases are attributed to the lack of updated data on the prevalence, geospatial distribution, population structures, and genotypic variants of the circulating M. tuberculosis.MethodsStructured questionnaire, mycobacterial culture, and standard 24-Mycobacterial Interspersed Repeated Units-Variable Number Tandem Repeats (MIRU-VNTR) were employed to collect sociodemographic characters, residence linked information, and genotype the isolates. The retrospective discrete Bernoulli model was used to identify the hot spot districts of sputum smear positivity, and Web-based Miru-VNTRPlus were used for the identification of lineages and sublineages.ResultsOut of 832 presumptive pulmonary tuberculosis (PTB) suspects, 119 (14.3%) were smear-positive. In the multivariate binary logistic model, PTB suspected patients in the age groups of 7–25 and 25–34 and those from rural residents were 4.53 (AOR = 4.53; 95% CI 2.25–9.13), 3.00 (AOR = 3.00; 95% CI 1.41–6.35) and 1.65 (AOR = 1.65; 95% CI 1.01–2.70) times at higher risk of turning smear-positive. Eleven (47.8%) districts of Arsi Zone were shown to have a high rate of clustering (RR = 2.27; 95% CI 1.62–3.2) of smear-positive PTB. Of 72 isolates queried for the lineage assignment, 59 (81.9%) were classified into the previously known lineages and 13 (18.1%) were not assigned to any known lineages. Overall, 42 (58.3%) belong to M. tuberculosis lineage 4 (Euro-American), 16 (22.2%) M. tuberculosis lineage 3 (Delhi/CAS), and 1 (1.4%) M. tuberculosis Lineage 1 (Indo-Oceanic/ East Africa Indian). Further classification to the sublineage indicates that the predominant lineage was Delhi/CAS comprising 16 (22.2%) isolates followed by 15 (20.8%) isolates belonging to Haarlem. The remaining isolates were distributed as 13 (18.1%) TUR, 6 (8.3%) LAM, 4 (5.5%) URAL, 4 (4.5%) NEW-1 and 1 (1.4%) EAI.ConclusionOur study showed higher smear-positive results among PTB suspected patients and remarkable spatial variation across districts of Arsi Zone in smear-positive PTB. This information together with the genotypic features could be used as input for the efforts of designing control strategies.
Highlights
Tuberculosis remains a serious public health concern globally
We aimed to determine the smear positivity, the geospatial clustering, and the genetic diversity of M. tuberculosis isolates obtained from Arsi Zone, Ethiopia
Sociodemographic characteristics, prevalence of smear positive and associated factors A total of 832 pulmonary tuberculosis (PTB) suspected patients participated in the study
Summary
Tuberculosis remains a serious public health concern globally. The enormous social, economic, and health impacts of the diseases are attributed to the lack of updated data on the prevalence, geospatial distribution, population structures, and genotypic variants of the circulating M. tuberculosis. Tuberculosis (TB) remains one of the major public health problems with an estimated 10 million new cases and 1.6 million deaths globally [1]. Despite the several efforts and achievements in the control of TB, the disease is among the major public health problems in the country with an estimated mortality of 24 cases/10,000 population. Previous spatial analyses of TB have been generally conducted using routinely collected TB notification data consisting of limited variables. Those studies usually focus on secondary data from health facilities and lack integrating the defining feature of heterogenicity of tuberculosis burden such as bacterial genetic characters
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