Epidemiological characteristics and spatial-temporal clustering of human brucellosis in Chenzhou, Hunan, 2015−2022

Objective Hunan province is a newly emerging epidemic area of human brucellosis, and the annual incidence rate shows an upward trend. In recent years, the reported case counts of human brucellosis in Chenzhou remained to be higher in Hunan. In this study, we analyzed the epidemiological characteristics and spatiotemporal clustering of brucellosis in Chenzhou from 2015 to 2022 to provide evidence for development and improvement of local human brucellosis prevention and control strategies.

Methods Descriptive method was used to analyze the epidemiological characteristics of reported cases of human brucellosis cases in Chenzhou from 2015 to 2022. Global spatial autocorrelation and hotspot analysis were applied to explore the spatiotemporal clustering of human brucellosis in Chenzhou during this period. Spearman correlation coefficient was used to analyze the correlation between the incidence of human brucellosis and the cattle and sheep stock, and the positive rate of animal brucellosis.

Results From 2015 to 2022, a total of 216 cases of human brucellosis were reported in Chenzhou, with an average annual incidence rate of 0.57/100 000. The overall incidence showed an increasing trend with slight decline. Spring and summer (April - July) were the incidence peak seasons. The male to female ratio of the cases was 2.86∶1. The age group 45− years had the highest case count, accounting for 47.22%. The majority of the cases were farmers (64.35%). The incidence of human brucellosis in 2016, 2018, and 2020 showed spatial autocorrelation (P＜0.05). In 2016 and 2018, the hotspot areas were mainly in some townships and streets in Suxian and Beihu and in several townships in Guiyang, Yizhang, and Yongxing, showing an expansion trend. In 2020, Linwu became a new hotspot area. There was no correlation between the cattle stock and the incidence rate of human brucellosis. In contrast, the sheep stock and the positive rate of animal brucellosis were correlated with the incidence rate of human brucellosis.

Conclusion The case count and incidence of human brucellosis in Chenzhou were in increase, there were high incidence hotspots, and the sheep stock and the positive rate of animal brucellosis were correlated with the incidence of human brucellosis. In order to effectively curb the spread of brucellosis and effectively prevent and control the prevalence of human brucellosis, it is necessary to strengthen the animal epidemic surveillance, strictly control the infection source, and conduct health education about brucellosis prevention and control and behavioral intervention.