Epidemiological Trends and Spatial Correlation Characteristics of Human Brucellosis in the Chinese Mainland From 2010 Through 2023

Human brucellosis remains endemic in the Chinese mainland, but its spatiotemporal dynamics remain unclear. This study employed descriptive epidemiology, joinpoint regression and spatial autocorrelation to map clustering patterns from 2010 through 2023. Joinpoint analysis identified an overall non-significant upward trend from 2010 to 2023 (average annual percent change = 5.965%, P = 0.200), with significant increases specifically during 2010-2015 (annual percent change = 10.55%, P = 0.041) and 2018-2023 (annual percent change = 14.48%, P = 0.008). Human brucellosis displays distinct seasonal variation, with peak incidence occurring in May across most regions and in June in the northwestern regions. The proportion of elderly patients (61–80 years) increased from 9.75% in 2010 to 21.85% in 2023, while the proportion of young and middle-aged adults (19–40 years) declined substantially from 37.17% to 20.52%. The 41–60 age group consistently constituted the majority of cases (52.92% overall). Furthermore, a median diagnostic delay of 14 days reflects critical gaps in early diagnosis of disease. Spatial analysis revealed significant spatial autocorrelation: high-high clusters were located primarily in northern regions and expanded from 156 to 359 counties, while low-low clusters in southern provinces decreased from 1752 to 1307 counties, indicating pronounced southward diffusion of the epidemic. The brucellosis epidemic in Chinese mainland represents a dynamic progression, marked by simultaneous increasing incidence, aging patient population, southward expansion and systemic diagnostic delays. An integrated strategy, featuring tailored surveillance, preemptive action in northern hotspots and accelerated diagnosis is urgently needed.