Factors associated with human brucellosis in Inner Mongolia Autonomous Region, China, 2014–2023: a Bayesian spatio-temporal analysis

Brucellosis is a neglected zoonotic disease and remains a global public health priority for the World Health Organization. Despite its significant global health burden, the disease remains substantially underreported in many regions. This study aimed to examine the associations between human brucellosis and its environmental, livestock-related, and socioeconomic variables in Inner Mongolia Autonomous Region from 2014 to 2023, utilizing a flexible Bayesian spatio-temporal framework. Descriptive epidemiological methods were employed to characterize the overall epidemic trends of brucellosis in Inner Mongolia. Subsequently, time series decomposition was utilized to analyze the temporal dynamics and seasonal patterns of brucellosis incidence. Candidate meteorological, socioeconomic, and livestock-related variables were screened for multicollinearity using Spearman correlation and variance inflation factor diagnostics. Four nested Bayesian spatio-temporal negative binomial models, incorporating spatial, temporal, and spatio-temporal interaction structures, were fitted and compared using the deviance information criterion and widely applicable information criterion, and the best-fitting model was used to estimate relative risks and 95% credible intervals for the association between each variable and brucellosis risk across the region. The incidence of brucellosis initially declined, then increased, and declined again, demonstrating pronounced seasonality in Inner Mongolia. Livestock inventory showed the strongest positive association with brucellosis risk (RR = 1.70, 95% CrI: 1.26–2.30), followed by GDP per capita (RR = 1.22, 95% CrI: 1.10–1.36) and temperature (RR = 1.19, 95% CrI: 1.10–1.28). Wind speed showed a weak but significant positive association (RR = 1.04, 95% CrI: 1.01–1.07), while NDVI was associated with reduced disease risk (RR = 0.93, 95% CrI: 0.90–0.97). Human brucellosis in Inner Mongolia exhibits significant seasonality and is associated with environmental and socioeconomic variables, particularly livestock husbandry intensity and regional economic activity. Prevention and control efforts may be intensified during the spring and summer months and in regions with high livestock density and active economic development. Furthermore, strengthening animal immunization, enhancing occupational protection, and improving surveillance in economically active livestock-producing regions may help reduce the regional disease burden. Not applicable.