Schistosomiasis trends and control efforts: a global perspective from 1990 to 2050

Background

Schistosomiasis is a chronic parasitic disease primarily endemic to tropical and subtropical regions, posing significant challenges to public health and economic development. Despite progress in global control efforts, the disease continues to be a major public health concern in high-burden countries such as China, Brazil, and Nigeria. This study seeks to assess the effectiveness of schistosomiasis control measures in these countries and on a global scale.

Methods

To analyze and visualize the distribution of schistosomiasis burden, data from the Global Burden of Disease (GBD) database for 2021 covering 204 countries were utilized. Statistical information on fatalities and Disability-Adjusted Life Years (DALYs) related to schistosomiasis from 1990 to 2021 was extracted, encompassing global, African, Asian, and American regions, as well as specific data for the countries of China, Brazil, and Nigeria. The Bayesian Average Annual Percentage Change (BAPC) model was applied for forecasting trends. Decomposition analysis was performed to assess the contributions of various factors to changes in disease burden, and the Annual Average Percentage Change (AAPC) was calculated using the Joinpoint model.

Results

Data from the GBD database reveal that the burden of schistosomiasis-related diseases is predominantly concentrated in Africa, Asia, and South America. In 2021, schistosomiasis-related DALYs in China and Brazil ranked 5th and 8th globally, respectively, while fatalities ranked 5th and 6th. Notably, schistosomiasis in Nigeria causes the highest DALYs and deaths globally. From 1990 to 2021, the AAPC in the burden of schistosomiasis-related diseases was negative globally, as well as in Africa, Asia, the Americas, and key countries such as China, Brazil, and Nigeria, with China showing the most significant decline. Between 2017 and 2021, the AAPC remained negative, with Africa registering the lowest AAPC during this period. Decomposition analysis identified population size, growth, and aging as the primary drivers of the increasing disease burden. In contrast, improvements in epidemiological factors, including reductions in incidence, case fatality rates and disease severity, partially countered this trend. Projections indicate that by 2050, the global burden of schistosomiasis will gradually decline, with China and Nigeria expected to achieve the lowest infection rates. However, Brazil is expected to experience a relatively slower decline.

Conclusion

This study analyzes the global burden of schistosomiasis from 1990 to 2021, showing an overall declining trend. While significant progress has been made in control measures in countries such as China, Brazil, and Nigeria, Nigeria remains the most severely affected, with the highest global DALYs and death tolls attributed to schistosomiasis. Despite the overall decline in disease burden, factors such as population growth and aging continue to drive an increase in the burden. Projections indicate that by 2050, the global burden of schistosomiasis will continue to decrease, with China and Nigeria expected to see the largest reductions, while Brazil will experience a relatively slower decline. These findings underscore the need for sustained and targeted control measures in high-burden countries.