Global, regional, and national temporal trend and patterns of change in the burden of leishmaniasis from 1990 to 2021: an analysis of the Global Burden of Disease Study 2021

Background

Leishmaniasis is a globally prevalent parasitic disease caused by protozoa of the genus Leishmania. This study utilizes Global Burden of Disease Study 2021 (GBD 2021) data to systematically evaluate the global, regional, and national epidemiological trends, thereby providing a scientific basis for optimizing the prevention and control strategies for leishmania infections.

Methods

Data from the GBD 2021 database were analyzed to evaluate trends in age-standardized incidence rate (ASIR), age-standardized prevalence rate (ASPR), age-standardized mortality rate (ASMR), and age-standardized disability-adjusted life-years rate (ASDR) for leishmaniasis across global, regional, and national levels, stratified by age, sex, and sociodemographic index (SDI). A Bayesian age-period-cohort (BAPC) model was employed to project future burden. Analyses included the slope index of inequality and the concentration index to assess health disparities, frontier analysis to estimate achievable outcomes based on development levels, and decomposition analysis to identify the drivers of changes in DALYs number.

Results

From 1990 to 2021, the ASIR of leishmaniasis decreased from 17.82 to 14.34 per 100,000 population, while the ASPR increased from 62.94 to 76.96 per 100,000 population. Most strikingly, the ASMR showed a dramatic reduction from 1.05 to 0.07 per 100,000 population. However, concerning increases were observed in absolute case numbers, with incident cases rising from 1.01 to 1.10 million and prevalent cases nearly doubling from 3.18 to 6.21 million. Notably, Syria exhibited the most severe deterioration in ASDR (average annual percentage change [AAPC] = 4.78 %, 95 % confidence interval [CI]: 4.67–4.89). Frontier analysis identified several high-burden countries including South Sudan, the Syrian Arab Republic, Afghanistan, Suriname, and Sudan as persistent hotspots requiring targeted interventions. A robust inverse correlation was observed between all disease metrics (ASIR, ASPR, ASMR, ASDR, and case counts) and the SDI, with all associations demonstrating high statistical significance (P < 0.001).

Conclusions

Leishmaniasis continues to pose significant public health challenges in Southeast Asia, North Africa, and Middle East. Strengthening public health interventions, optimizing resource distribution, and focusing on health governance in low- and middle-income countries are key to addressing the ongoing burden. One Health-based integrated strategies, particularly in vector control, host management, and environmental sanitation, are essential for reducing the disease burden and achieving long-term control.