Global, regional, and national age-specific progress towards the 2020 milestones of the WHO End TB Strategy: a systematic analysis for the Global Burden of Disease Study 2021

Background Global evaluations of the progress towards the WHO End TB Strategy 2020 interim milestones on mortality (35% reduction) and incidence (20% reduction) have not been age specific. We aimed to assess global, regional, and national-level burdens of and trends in tuberculosis and its risk factors across five separate age groups, from 1990 to 2021, and to report on age-specific progress between 2015 and 2020. Methods We used the Global Burden of Diseases, Injuries, and Risk Factors Study 2021 (GBD 2021) analytical framework to compute age-specific tuberculosis mortality and incidence estimates for 204 countries and territories (1990–2021 inclusive). We quantified tuberculosis mortality among individuals without HIV co-infection using 22 603 site-years of vital registration data, 1718 site-years of verbal autopsy data, 825 site-years of sample-based vital registration data, 680 site-years of mortality surveillance data, and 9 site-years of minimally invasive tissue sample (MITS) diagnoses data as inputs into the Cause of Death Ensemble modelling platform. Age-specific HIV and tuberculosis deaths were established with a population attributable fraction approach. We analysed all available population-based data sources, including prevalence surveys, annual case notifications, tuberculin surveys, and tuberculosis mortality, in DisMod-MR 2.1 to produce internally consistent age-specific estimates of tuberculosis incidence, prevalence, and mortality. We also estimated age-specific tuberculosis mortality without HIV co-infection that is attributable to the independent and combined effects of three risk factors (smoking, alcohol use, and diabetes). As a secondary analysis, we examined the potential impact of the COVID-19 pandemic on tuberculosis mortality without HIV co-infection by comparing expected tuberculosis deaths, modelled with trends in tuberculosis deaths from 2015 to 2019 in vital registration data, with observed tuberculosis deaths in 2020 and 2021 for countries with available cause-specific mortality data. Findings We estimated 9·40 million (95% uncertainty interval [UI] 8·36 to 10·5) tuberculosis incident cases and 1·35 million (1·23 to 1·52) deaths due to tuberculosis in 2021. At the global level, the all-age tuberculosis incidence rate declined by 6·26% (5·27 to 7·25) between 2015 and 2020 (the WHO End TB strategy evaluation period). 15 of 204 countries achieved a 20% decrease in all-age tuberculosis incidence between 2015 and 2020, eight of which were in western sub-Saharan Africa. When stratified by age, global tuberculosis incidence rates decreased by 16·5% (14·8 to 18·4) in children younger than 5 years, 16·2% (14·2 to 17·9) in those aged 5–14 years, 6·29% (5·05 to 7·70) in those aged 15–49 years, 5·72% (4·02 to 7·39) in those aged 50–69 years, and 8·48% (6·74 to 10·4) in those aged 70 years and older, from 2015 to 2020. Global tuberculosis deaths decreased by 11·9% (5·77 to 17·0) from 2015 to 2020. 17 countries attained a 35% reduction in deaths due to tuberculosis between 2015 and 2020, most of which were in eastern Europe (six countries) and central Europe (four countries). There was variable progress by age: a 35·3% (26·7 to 41·7) decrease in tuberculosis deaths in children younger than 5 years, a 29·5% (25·5 to 34·1) decrease in those aged 5–14 years, a 15·2% (10·0 to 20·2) decrease in those aged 15–49 years, a 7·97% (0·472 to 14·1) decrease in those aged 50–69 years, and a 3·29% (–5·56 to 9·07) decrease in those aged 70 years and older. Removing the combined effects of the three attributable risk factors would have reduced the number of all-age tuberculosis deaths from 1·39 million (1·28 to 1·54) to 1·00 million (0·703 to 1·23) in 2020, representing a 36·5% (21·5 to 54·8) reduction in tuberculosis deaths compared to those observed in 2015. 41 countries were included in our analysis of the impact of the COVID-19 pandemic on tuberculosis deaths without HIV co-infection in 2020, and 20 countries were included in the analysis for 2021. In 2020, 50 900 (95% CI 49 700 to 52 400) deaths were expected across all ages, compared to an observed 45 500 deaths, corresponding to 5340 (4070 to 6920) fewer deaths; in 2021, 39 600 (38 300 to 41 100) deaths were expected across all ages compared to an observed 39 000 deaths, corresponding to 657 (–713 to 2180) fewer deaths. Interpretation Despite accelerated progress in reducing the global burden of tuberculosis in the past decade, the world did not attain the first interim milestones of the WHO End TB Strategy in 2020. The pace of decline has been unequal with respect to age, with older adults (ie, those aged >50 years) having the slowest progress. As countries refine their national tuberculosis programmes and recalibrate for achieving the 2035 targets, they could consider learning from the strategies of countries that achieved the 2020 milestones, as well as consider targeted interventions to improve outcomes in older age groups

Cutting propagation of Santalum austrocaledonicum: the effect of genotype, cutting source, cutting size, propagation medium, IBA and irradiance

Developing methods for routine clonal propagation of sandalwood (Santalum austrocaledonicum) is important for its domestication and development as a commercial agroforestry species. The amenability of this species to propagation by leafy stem cuttings in low-cost non-mist propagators was assessed in four separate experiments. These experiments evaluated the effects of (1) genotype (15 genotypes from two island provenances), (2) cutting position on the stock plant (apical, medial and basal), (3) cutting size (1-node/400 mm2 and 2-node/800 mm2 leaf area), (4) three propagation media [scoria (5 mm, air-filled porosity (AFP)—29%), vermiculite and perlite (1:1 v/v, AFP—46%) and vermiculite, perlite and peat (2:2:1 v/v/v, AFP—42%)], (5) indole-3-butyric (IBA) (3000, 4000 and 8000 ppm) and (6) irradiance in the propagator [daily light integral (DLI) 5.3, 3.9, 2.6, 2.2 mol m−2 day−1]. IBA, propagation media and cutting size had no significant effect on rooting percentage, root number or root growth. Evidence of provenance-based variation in rooting capacity was recorded with greater rooting success for genotypes from the island of Erromango compared with Tanna. Variation in adventitious root induction was also recorded between individual genotypes from Erromango across all four experiments. Cuttings collected from the apical and medial parts of the shoot on the stock plant had higher rooting percentage than those collected from the base. Differences in rooting capacity between apical and medial shoots were variable between experiments and may be attributed to different levels of hardening. The use of artificial shade (~ 70%) to achieve a mean DLI of between 2.6 and 3.9 mol m−2 day−1 increased rooting percentage compared to both lower (2.2 mol m−2 day−1 or ~ 90% shade) and higher (5.3 mol m−2 day−1 or ~ 50% shade) irradiance treatments. Leaf retention of cuttings in the propagator was positively associated with the percentage of cuttings with adventitious roots, with highest percentage in cuttings with full leaf retention, regardless of original cutting size. This study demonstrated S. austrocaledonicum seedlings can be successfully propagated by cuttings provided the propagation conditions are optimized for each genotype. © 2018 Springer Science+Business Media B.V., part of Springer Natur