Prioritizing interventions for echinococcosis prevention in China: a population attributable fraction analysis

Despite population-level control efforts, human echinococcosis continues to pose a public health challenge in China. Targeting modifiable risk factors at the individual level could be another recipe, but the priority targets for intervention remain unclear. Our aim was to quantify the potential health gains of hypothetical interventions on modifiable risk factors for human echinococcosis, informing effective control strategies.

We collected and aggregated data on the association between modifiable risk factors and human echinococcosis and national total echinococcosis (cystic echinococcosis [CE], alveolar echinococcosis [AE], and other unclassified cases) incidence during 2007-2020 in China. A Bayesian hierarchical model was developed to pool effect estimates for modifiable risk factors associated with total echinococcosis and its subtypes (CE and AE), while accounting for the adequacy of confounding adjustment. Additionally, we evaluated the preventable burden of human echinococcosis via the annual number of total echinococcosis cases attributable to modifiable risk factors deriving from the population attributable fractions (PAFs).

Twelve risk factors for human echinococcosis were identified from 25 studies across nine endemic provinces and autonomous regions in China, with PAFs ranging from 2.2% to 41.2%. The highest PAFs were observed for surface water sources for drinking (PAF: 41.2%; 95% confidence interval [CI]: 18.9-55.9) and the presence of stray dogs around residences (PAF: 34.9%; 15.8-55.1), accounting for 1437 (95% CI: 658-1947) and 1216 (552-1921) preventable annual total echinococcosis cases, respectively. Drinking unboiled water followed, with a PAF of 33.5% (6.2-54.8) and 1167 (217-1910) preventable cases annually. In contrast, the lowest PAF was estimated for exposure to foxes or fox-derived materials (PAF: 2.2%; 0.5-4.3). Surface water sources for drinking and free-roaming owned dogs showed the highest PAFs for CE (42.6%; 19.7-56.5) and AE (49.4%; 34.8-60.2), respectively. Simultaneously eliminating the presence of stray dogs around residences and surface water sources for drinking was the most-effective among available pair-wise combination of risk factors, in which 75.3% (1621/2152) of preventable total echinococcosis cases are concentrated in Xinjiang Uygur Autonomous Region (833; 519-1005), Qinghai Province (396; 247-478), and Sichuan Province (392; 244-473).

Interventions targeting drinking water safety and responsible dog management could reduce echinococcosis incidence in China. Public health efforts should prioritize high-prevalence regions such as Xinjiang Uygur Autonomous Region, Qinghai Province, and Sichuan Province to maximize impact.

NHC Key Laboratory of Echinococcosis Prevention and Control (no. 21H1234) and Postdoctoral Fellowship Program of CPSF (no. GZB20250191).