Epidemiological transitions of Visceral Leishmaniasis in G20 countries: A 33-year retrospective joinpoint and demographic decomposition analysis with 20-year ARIMA projections.

BACKGROUND: Visceral leishmaniasis (VL) remains a fatal neglected tropical disease with substantial global burden. The Group of Twenty (G20) encompasses both endemic and non-endemic nations, yet comprehensive multi-country assessments of VL trends and future projections are limited. This study aims to evaluate the 33-year epidemiological transition of VL across G20 countries and forecast its trajectory to 2043. METHODOLOGY/PRINCIPAL FINDINGS: We extracted VL-related prevalence, incidence, mortality, and disability-adjusted life years (DALYs) data for G20 countries from the Global Burden of Disease 2023 database (1990-2023). We employed joinpoint regression to identify trend inflection points, decomposition analysis to quantify drivers of change (population growth, aging, and epidemiological changes), and autoregressive integrated moving average (ARIMA) models to project trends to 2043. From 1990 to 2023, G20 countries showed significant declines in age-standardized prevalence rate (EAPC = -9.06%), incidence rate (EAPC = -9.06%), mortality rate (EAPC = -7.23%), and DALYs rate (EAPC = -7.40%). Saudi Arabia, Turkey, and India experienced the steepest declines, while Brazil exhibited the smallest reduction and the highest burden in 2023 (age-standardized DALY rate: 30.54 per 100,000). Burden was consistently higher in males and concentrated in children under 5 years, with a slight increase observed among those aged ≥95 years. Decomposition analysis revealed that changes in epidemiological rates were the primary driver of mortality (contributing -82.05%) and DALYs (-52.62%) reductions, counteracting the positive effects of population growth and aging. ARIMA projections (2024-2043) suggest a stabilization in mortality, a gradual decline in DALYs, and a subtle increase in incidence and prevalence rates, with persistent gender disparities. CONCLUSIONS/SIGNIFICANCE: While the VL burden in G20 nations has significantly decreased, substantial national disparities are evident. Our analysis specifically identifies Brazil as the priority target for intensified control. Sustained surveillance and international cooperation are crucial to prevent a projected mild resurgence in new infections.