Latent tuberculosis infection and associated risk indicators in pastoral communities in southern Ethiopia: a community based cross-sectional study

Abstract

BackgroundResearch pertaining to the community-based prevalence of latent tuberculosis infection (LTBI) is important to understand the magnitude of this infection. This study was conducted to estimate LTBI prevalence and to identify associated risk factors in the Omo Zone of Southern Ethiopia.MethodsA community-based cross-sectional study was conducted in six South Omo districts from May 2015 to February 2016. The sample size was allocated to the study districts proportional to their population sizes. Participants were selected using a multi-stage sampling approach. A total of 497 adult pastoralists were recruited. Blood samples were collected from the study participants and screened for LTBI using a U.S. Food and Drug Administration approved interferon-gamma release assay (IGRA). Logistic regression was used to model the likelihood of LTBI occurrence and to identify risk factors associated with LTBI.ResultsThe prevalence of LTBI was 50.5% (95% CI: 46%, 55%) with no significant gender difference (49.8% among males versus 51.2% among females; Chi-square (χ2) = 0.10; P = 0.41) and marginally non-significant increasing trends with age (44.6% among those below 24 years and 59.7% in the age range of 45-64 years; χ2 = 6.91; P = 0.075). Being residence of the Dasanech District (adjusted odds ratio, AOR = 2.62, 95% CI: 1.30, 5.28; P = 0.007) and having a habit of eating raw meat (AOR = 2.89, 95% CI: 1.09, 7.66; P = 0.033) were significantly associated with an increased odds of being positive for LTBI. A large family size (size of 5 to 10) has significant protective effect against associated a reduced odds of being positive for LTBI compared to a family size of below 5 (AOR = 0.65, 95% CI: 0.42, 0.99; P = 0.045).ConclusionsA high prevalence of LTBI in the South Omo Zone raises the concern that elimination of TB in the pastoral communities of the region might be difficult. Screening for and testing individuals infected with TB, independent of symptoms, may be an effective way to minimize the risk of disease spread.

Prevalence of latent tuberculosis infection and associated risk factors in prison in East Wollega Zone of western Ethiopia

“…Thus, this cross-sectional study was to estimate IGRA based prevalence of LTBI and the possible associated risk factors in East Wollega Zonal prisoners. The prevalence observed in this study (51.7%) was different from the prevalence of LTI among the general population as noted by the WHO, which estimates it around 30% [3], as well as by a study carried out in the general Ethiopia population which estimates it around 46% [21] and congruent with pastoral communities in Southern part of Ethiopia (50.5%) [22]. In our findings the prevalence of LTBI were markedly higher than the prevalence in prisons of countries like USA (6.3%) [23]; UK (11.5%) [24], (7.1%) [25]; Australia (14.0%) [26]; Italy PLOS ONE (17.9%) [27]; Canada (32.3%) [28]; Spain (40.3%) [29]; Switzerland (46.9%) [30] and Minas Gerais (25.2%) [31].…”

Protein and Microbial Biomarkers in Sputum Discern Acute and Latent Tuberculosis in Investigation of Pastoral Ethiopian Cohort

“…Many of its people have a traditional lifestyle as cattle herders or in subsistence agriculture with little access to medical care. A subset of the nearly 2,000 participants in a molecular epidemiological study of TB [32] were used here to analyze sputum proteomes and microbiomes. The major ethnic groups were Hamar, Daasanech, Bena, Tsemay, Selamago, Maale, Ari, and Nyangatom.…”

“…Nearly 1,200 sputum and blood samples were collected. Of those, nearly 13% were positive using acid-fast bacilli (AFB) smear microscopy or by isolating Mycobacterium tuberculosis complex (MTBC) strains on Lowenstein Jensen medium [31]; 50.5% were positive for LTBI employing IFN-γ assays [32]. Subjects positive for PTB were offered DOTS treatment [33] at a clinic close to their residences.…”

“…Subjects positive for PTB were offered DOTS treatment [33] at a clinic close to their residences. Information on geographic and socio-economic characteristics, ethnic affiliations, exclusion from participation, and other medical data were reported recently [31, 32]. The Institutional Review Board at Aklilu Lemma Institute of Pathobiology, Addis Ababa University (ALIPB-AAU) under ref.…”

“…The LTBI sub-group was later distinguished from NCC subjects based on data from QuantiFERON-TB Gold In-Tube test (GFT-GIT) assays. We set the positivity threshold for LTBI at the recommended > 0.35 IU/ml [32].…”