[Epidemiological characteristics of bacillary dysentery in China, 2005-2024]

Objective: The objective of this study was to understand the incidence, spatial and temporal distribution characteristics and trends of bacillary dysentery in China from 2005 to 2024 in order to identify the high-risk groups and reveal the potential risk factors and to provide a scientific basis for optimizing the allocation of preventive and control resources, formulating targeted intervention strategies and assessing the effectiveness of the measures. Methods: The nationally reported incidence data of bacillary dysentery was collected from 2005 to 2024 in the Chinese Center for Disease Control and Prevention National Notifiable Diseases Reporting Information System. Descriptive epidemiological methods were used to analyze the population characteristics of bacillary dysentery cases. A Joinpoint regression model was constructed to examine long-term trends in reported incidence rates and spatial dynamic window scanning statistics were applied to detect spatial clusters of bacillary dysentery cases. Results: Between 2005 and 2024, 3 520 247 cases of bacillary dysentery were reported across China, with an average incidence rate of 12.88 per 100 000 people, after which the rate of decline decreased. The incidence rate showed a general downward trend, featuring a significant inflection point in 2016. It exhibited marked seasonality, peaking from May to October (summer-autumn), which weakened over time. From 2005 to 2024, the most likely clusters were in Beijing and Tianjin. Males, infants, the elderly, farmers, and children not in daycare showed many cases. Conclusions: The results revealed that the peak incidence of bacillary dysentery in China from 2005 to 2024 was featured in the summer-autumn months. High-incidence areas were mainly Beijing and Tianjin. The key groups, including males, infants, the elderly, farmers and children not in daycare, were identified. Enhancing surveillance, targeted health education, and preventive measures, especially in these key populations and in regions where the disease shows a high incidence should be strengthened.