Spatiotemporal trends and risk factors of small-ruminant brucellosis in China: A systematic review and meta-analysis.

Abstract

Brucellosis remains a neglected zoonosis that threatens livestock production and human health in China. Small ruminants are key reservoirs, yet brucellosis in sheep and goats is still insufficiently characterized in terms of seroprevalence, risk factors, and spatial-temporal dynamics. We conducted a nationwide systematic review and meta-analysis (PRISMA) of studies published up to 1 August 2025. We pooled eligible cross-sectional data using a random-effects model, explored determinants by subgroup analysis and meta-regression, and applied ARIMA models to forecast trends. We included 306 studies from 27 provinces. The overall pooled seroprevalence was 3.0&#x202f;% (95&#x202f;% CI 2.3-3.8), with strong geographic heterogeneity. The highest burden occurred in North China, especially Inner Mongolia. Risk was higher in spring and in BSk (cold semi-arid) climates. Seroprevalence was slightly higher in goats, young animals (<1 year), and stall-feeding systems, indicating the need to strengthen housing hygiene and farm biosecurity. Diagnostic methods explained substantial heterogeneity: RBPT tended to yield higher estimates, whereas ELISA/cELISA offer better diagnostic performance. Seroprevalence rose around 2016-2017 and then declined only modestly. Forecasts suggested a continued upward drift (0.76&#x202f;% in 2026-0.84&#x202f;% in 2027), implying sustained One Health risks. These findings support region-specific vaccination with priority for goats, expanded standardized ELISA/cELISA use, and integrated human-livestock surveillance with harmonized reporting and targeted protection for high-risk workers in hotspot regions.