Prevalence and spatial distribution characteristics of human brucellosis in Ningxia from 2010 to 2024

Brucellosis, a neglected zoonotic disease as defined by the World Health Organization (WHO), represents a substantial burden, causing both severe human morbidity and significant economic losses to the livestock industry. In recent years, the Ningxia Hui Autonomous Region (Ningxia) in northwest China has emerged as a region with persistently high endemicity of human brucellosis. An in-depth analysis of the epidemic's prevalence and spatiotemporal evolution in this region is essential to inform the optimization of targeted prevention and control measures.

Data on all human brucellosis cases from 2010 to 2024 were collected from the China Information System for Disease Control and Prevention. Temporal trends, global and local spatial autocorrelation, and spatial scan statistics were used to explore temporal patterns, regional clustering, and high-risk areas.

A total of 35 665 human brucellosis cases were reported in Ningxia, with no associated deaths, during the study period. The average annual incidence rates was 35.08/100,000, ranging from 3.31 to 84.80 per 100,000. Two incidence peaks were observed: the first in 2015 (43.66/100,000) and the second in 2022 (84.80/100,000). The human brucellosis incidence rates showed that overall increasing trend from 2010 to 2024 (average annual percentage change [AAPC]=18.31%, but this was not statistically significant (t = 1.63, P = 0.102). Male accounted for 71.01% (25 325 cases) of all cases, 2.45 times higher than females (28.99%, 10 340 cases). Cases were reported in all 22 counties of Ningxia. The top five counties with the highest average annual incidence were: Yanchi County (184.79/100,000), Tongxin County (75.91/100,000), Zhongning County (46.47/100,000), Xiji County (46.15/100,000) and Yuanzhou District (45.30/100,000), while Xingqing District had the lowest rate (5.60/100,000). The top five counties with the fastest AAPC were: Huinong District (AAPC = 140.46%), Qingtongxia City (AAPC = 127.19%), Pengyang County (AAPC = 111.19%), Haiyuan County (AAPC = 107.97%) and Lingwu County (AAPC = 102.04%). Global spatial autocorrelation analysis revealed spatial clustering of human brucellosis incidence between 2022-2024 (Moran's I 0.266, p = 0.033; 0.394, p < 0.001; 0.353,p = 0.002, respectively). Local spatial autocorrelation identified "high-high" clusters primarily in Zhongning County, Tongxin County and Lingwu County. Additionally, spatial scanning analysis detected four spatial clusters, including one most likely cluster (LLR = 6474.66, RR = 3.71, P  ( 0.001) and three secondary clusters. The primary cluster center was located at Jingyuan County (38.10°N, 106.34°E), with a cluster radius of 271.44 km.

Our findings reveal a substantial burden of human brucellosis in Ningxia. The disease exhibits distinct seasonality, peaking in summer and autumn. Priority interventions should include: (1) Enhanced health education and targeted behavioral interventions for middle-aged and elderly males to improve personal awareness and competency in prevention and control; and (2) Timely identification of key risk factors and implementation of tailored prevention strategies in regions experiencing either a rapid increase or persistently high incidence.