Unlabelled: Urgent improvements in the diagnosis and management of infection are required to reach End TB goals. Conventional interferon-gamma release assays (IGRAs), such as QuantiFERON-TB Gold Plus (QFT-Plus), require substantial laboratory infrastructure and large blood volumes, limiting use in high-burden settings. The QIAreach QuantiFERON-TB (QIAreach QFT) was developed to overcome these challenges but has not previously been evaluated in field conditions in a low-income, high-burden country, or at scale in children.
View Article and Find Full Text PDFBMC Glob Public Health
February 2024
Community-based active case finding (ACF) for tuberculosis (TB) involves an offer of screening to populations at risk of TB, oftentimes with additional health promotion, community engagement and health service strengthening. Recently updated World Health Organization TB screening guidelines conditionally recommend expanded offer of ACF for communities where the prevalence of undiagnosed pulmonary TB is greater than 0.5% among adults, or with other structural risk factors for TB.
View Article and Find Full Text PDFCurrent passive case-finding policies have not resulted in the expected decline in tuberculosis incidence. Recognition of the variety of disease pathways experienced by individuals with tuberculosis highlights how many are not served by the current prevention and care system and how much transmission is missed.
View Article and Find Full Text PDFTuberculosis (TB) transmission and prevalence are dynamic over time, and heterogeneous within populations. Public health programmes therefore require up-to-date, accurate epidemiological data to appropriately allocate resources, target interventions, and track progress towards End TB goals. Current methods of TB surveillance often rely on case notifications, which are biased by access to healthcare, and TB disease prevalence surveys, which are highly resource-intensive, requiring many tens of thousands of people to be tested to identify high-risk groups or capture trends.
View Article and Find Full Text PDFBackground: Individuals with bacteriologically confirmed pulmonary tuberculosis (TB) disease who do not report symptoms (subclinical TB) represent around half of all prevalent cases of TB, yet their contribution to () transmission is unknown, especially compared to individuals who report symptoms at the time of diagnosis (clinical TB). Relative infectiousness can be approximated by cumulative infections in household contacts, but such data are rare.
Methods: We reviewed the literature to identify studies where surveys of infection were linked to population surveys of TB disease.
Proc Natl Acad Sci U S A
November 2023
Traditional understanding of the risk of progression from () infection to tuberculosis (TB) overlooks diverse presentations across a spectrum of disease. We developed a deterministic model of infection and minimal (pathological damage but not infectious), subclinical (infectious but no reported symptoms), and clinical (infectious and symptomatic) TB, informed by a rigorous evaluation of data from a systematic review of TB natural history. Using a Bayesian approach, we calibrated the model to data from historical cohorts that followed tuberculin-negative individuals to tuberculin conversion and TB, as well as data from cohorts that followed progression and regression between disease states, disease state prevalence ratios, disease duration, and mortality.
View Article and Find Full Text PDFBackground: Prevalence surveys show a substantial burden of subclinical (asymptomatic but infectious) tuberculosis, from which individuals can progress, regress, or even persist in a chronic disease state. We aimed to quantify these pathways across the spectrum of tuberculosis disease.
Methods: We created a deterministic framework of untreated tuberculosis disease with progression and regression between three states of pulmonary tuberculosis disease: minimal (non-infectious), subclinical (asymptomatic but infectious), and clinical (symptomatic and infectious).
High prevalence of infectious tuberculosis among men suggests potential population-wide benefits from addressing programmatic and social determinants of gender disparities. Utilising a sex-stratified compartmental transmission model calibrated to tuberculosis burden estimates for Viet Nam, we modelled interventions to increase active case finding, to reduce tobacco smoking, and to reduce alcohol consumption by 2025 in line with national and global targets. For each intervention, we examined scenarios differentially targeting men and women and evaluated impact on tuberculosis morbidity and mortality in men, women, and children in 2035.
View Article and Find Full Text PDFA key metric in tuberculosis epidemiology is the annual risk of infection (ARI), which is usually derived from tuberculin skin test (TST) and interferon-γ release assay (IGRA) prevalence surveys carried out in children. Derivation of the ARI assumes that immunoreactivity is persistent over time; however, reversion of immunoreactivity has long been documented. We used a deterministic, compartmental model of Mycobacterium tuberculosis (Mtb) infection to explore the impact of reversion on ARI estimation using age-specific reversion probabilities for the TST and IGRA.
View Article and Find Full Text PDFBackground: Tuberculosis remains a major public health priority and is the second leading cause of mortality from infectious disease worldwide. TB case detection rates are unacceptably low for men, the elderly and children. Disruptions in TB services due to the COVID-19 pandemic may have exacerbated these and other inequalities.
View Article and Find Full Text PDFLocal information is needed to guide targeted interventions for respiratory infections such as tuberculosis (TB). Case notification rates (CNRs) are readily available, but systematically underestimate true disease burden in neighbourhoods with high diagnostic access barriers. We explored a novel approach, adjusting CNRs for under-notification (P:N ratio) using neighbourhood-level predictors of TB prevalence-to-notification ratios.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
June 2022
Angiogenic VEGF isoforms are upregulated in diabetic retinopathy (DR), driving pathological growth and fluid leakage. Serine-arginine-rich protein kinase-1 (SRPK1) regulates VEGF splicing, and its inhibition blocks angiogenesis. We tested the hypothesis that SRPK1 is activated in diabetes, and an SRPK1 inhibitor (SPHINX31) switches VEGF splicing in DR and prevents increased vascular permeability into the retina.
View Article and Find Full Text PDFBackground: Ratios of bacteriologically positive tuberculosis (TB) prevalence to notification rates are used to characterise typical durations of TB disease. However, this ignores the clinical spectrum of tuberculosis disease and potentially long infectious periods with minimal or no symptoms prior to care-seeking.
Methods: We developed novel statistical models to estimate progression from initial bacteriological positivity including smear conversion, symptom onset and initial care-seeking.
Globally, men have higher tuberculosis (TB) burden but the mechanisms underlying this sex disparity are not fully understood. Recent surveys of social mixing patterns have established moderate preferential within-sex mixing in many settings. This assortative mixing could amplify differences from other causes.
View Article and Find Full Text PDFDeath-associated protein (DAP) undergoes substantial changes in expression during turkey skeletal muscle development, decreasing from the 18 day embryonic stage to 1 day posthatch, and again from 1 day posthatch to 16 weeks of age. These changes suggest that DAP plays an important role at critical stages of the developmental process. The objective of this study was to elucidate the role of DAP in muscle development by examining the effect of reduced expression on global gene expression in proliferating and differentiating turkey muscle satellite cells.
View Article and Find Full Text PDFMales are at an increased risk of tuberculosis (TB) disease compared to females. Additionally, several risk factors for multidrug-resistant (MDR) or rifampicin-resistant (RR) TB disease are more common in males, hence male TB patients may have a higher relative risk of MDR/RR-TB than female TB patients.We used sex-disaggregated data of TB patients reported to the World Health Organization for 106 countries to calculate male-to-female (M:F) risk ratios of having MDR/RR-TB.
View Article and Find Full Text PDFTuberculosis (TB) is treatable but is the leading infectious cause of death worldwide, with men over-represented in some key aspects of the disease burden. Men's TB epidemiological scenario occurs within a wider public health and historical context, including their prior sidelining in health discussions. Differences are however noticeable in how some Western countries and high TB and HIV burden low and middle-income countries (LMIC) including in Africa have approached the subject(s) of men and health.
View Article and Find Full Text PDFIntroduction: HIV and tuberculosis (TB) remain leading causes of preventable death in low- and middle-income countries (LMICs). The World Health Organization (WHO) recommends HIV testing for all individuals with TB symptoms, but implementation has been suboptimal. We conducted a systematic literature review and meta-analyses to estimate HIV and TB prevalence, and short-term (two to six months) mortality, among adults with TB symptoms at community- and facility level.
View Article and Find Full Text PDFGlobally, men have a higher epidemiologic burden of tuberculosis (incidence, prevalence, mortality) than women do, possibly due to differences in disease incidence, treatment initiation, self-cure, and/or untreated-tuberculosis mortality rates. Using a simple, sex-stratified compartmental model, we employed a Bayesian approach to explore which factors most likely explain men's higher burden. We applied the model to smear-positive pulmonary tuberculosis in Vietnam (2006-2007) and Malawi (2013-2014).
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