Epidemiological characteristics and spatial clustering of brucellosis in Wuwei , Gansu, 2005−2022

Objective To analyze the epidemiological characteristics and spatial distribution of brucellosis in Wuwei, Gansu province, from 2005 to 2022 and provide reference for the development of brucellosis prevention and control measures.

Methods The incidence data of brucellosis in Wuwei from 2005 to 2022 were collected from National Infectious Disease Reporting Information Management System. Global spatial autocorrelation analysis was used to investigate the spatial clustering of brucellosis cases. In contrast, local spatial clustering analysis was used to understand the distribution of disease clusters. Furthermore, Pearson correlation analysis was used to explore the potential relationship between the number of brucellosis cases and the population of cattle and sheep.

Results A total of 3455 brucellosis cases were reported in Wuwei during 2005–2022. The annual incidence of brucellosis showed a continual upward trend, with an average annual rate of 10.77/100 000. The male to female ratio of the cases was 2.48∶1. In terms of occupational distribution, the cases in farmers accounted for 85.88%. The majority of cases (86.37%) were aged 30–69 years, with a median age of 50 years. The incidence peaked during March-August. From 2008 to 2022, the spatial distribution of brucellosis cases showed clear clustering, which became more obvious as time passed. The brucellosis hotspot areas showed gradual expansion, altering within Tianzhu, Minqin and Gulang counties. A positive correlation was found between local brucellosis case number and the local stocks of cattle and sheep. The correlation with the stock of sheep was stronger compared with stock of cattle.

Conclusion The incidence of brucellosis in Wuwei continued to increase during 2005–2022, exhibiting clear spatial clustering, stead increase of townships with high incidence, and alters of hotspot areas. This trend was closely associated with the rapid development of the animal breeding industry. It is necessary to promote human-animal segregation based on strengthened livestock quarantine measures, immunization, and purification, take targeted measures in the health education and intervention in farmers and the elderly and conduct serological screening for brucellosis in key populations in hotspot areas.