[Assessment of the burden of clonorchiasis and its temporal changes in China]

To assess the burden of clonorchiasis and identify its temporal and spatial changes in China, thus to provide insights into the control and prevention of the diseases.

The disability-adjusted life years (DALYs) was employed as the primary indicator for the disease burden. The prevalence data of Clonorchis sinensis infection were obtainted from the three national surveys on important human parasitic diseases in China, conducting during the period from 1988 to 1922, from 2001 to 2004 and from 2014 to 2016, respectively, and the demographic data from National Bureau of Statistics of China. DALYs of clonorchiasis were calculated and the temporal changes were analyzed at both national and provincial levels, using the disability weight (DW) obtained from a community study in China. Sensitivity analysis was carried out to compare the resulted DALYs of China calculated under the method adopted in this study and that calculated with other commonly used methods.

The national burden of clonorchiasis was 489174.04 [95% confidence interval (CI): (391648.87, 597509.87)] DALYs in China in 2016, indicating 0.36 [95% CI: (0.28, 0.43)] DALYs per 1 000 populations. The regions with a high burden of clonorchiasis were concentrated in southern China and northeastern China, and the provinces with the three highest burdens of clonorchiasis included Guangxi Zhuang Autonomous Region, Guangdong Province and Heilongjiang Province, which accounted for 91.18% of total burdens of clonorchiasis in China. During the periods of the three national surveys on important human parasitic diseases in China, the national burden of clonorchiasis was found to show a tendency of first rise and then decrease in China; however, the burden of clonorchiasis has recently shown a tendency towards a rise in Guangxi Zhuang Autonomous Region, Heilongjiang Province and Jiangxi Province. Sensitivity analysis showed that the calculation of diseases burden with age-stratified prevalence of clonorchiasis was similar to that of our method without age stratification; however, the burden estimates calculated only based on the DW of the severe symptoms were much lower than our estimates.

The burden of clonorchiasis is high in China, with a large regional difference. Recently, the overall burden of clonorchiasis has shown a tendency of decline in China; however, there is a tendency towards a rise in some provinces. Therefore, the control of clonorchiasis requires more adaptations to local circumstances.