Epidemic Characteristics, High-Risk Areas and Space-Time Clusters of Human Brucellosis - China, 2020-2021.

INTRODUCTION

Analyze the recent epidemiological and temporal-spatial characteristics of human brucellosis in China and provide information for adjusting strategies for brucellosis control.

METHODS

Human brucellosis data were obtained from the National Notifiable Disease Reporting System (NNDRS). A geographical information system (GIS) was used to visualize high-risk areas with annual incidence based on county (district) polygons. The space-time scan statistic (STSS) was applied to detect the space-time clusters of human brucellosis.

RESULTS

A total of 69,767 cases were reported from 2,083 counties in the mainland of China in 2021, a 47.7% increase from 2020 (47,425). About 95.5% of the total cases were centralized in northern China and 31.8% in Inner Mongolia (IM). The number of counties with an incidence exceeding 100 per 100,000 was 34 in 2020 and 65 in 2021. From 2020 to 2021, 24 space-time clusters were detected. The two primary clusters were located northeast of IM, including 109 counties. The secondary clusters affected 208 counties in 2020 and spread to 297 counties in 2021, the majority of which were located in the middle of IM, exhibiting a trend spreading west from IM to neighboring provincial-level administrative divisions (PLADs).

CONCLUSIONS

From 2020 to 2021, the incidence of human brucellosis nationwide was exponential, demonstrating distinct spatiotemporal characteristics. Space-time clusters were located in IM and neighboring areas. Therefore, considerable efforts are required to curb this momentum.