<p>Multivariate logistic regression results.</p>

Introduction Bovine brucellosis, caused primarily by Brucella abortus, remains a major constraint to livestock productivity and a persistent zoonotic threat. Although brucellosis is a controlled disease in South Africa, detailed subnational epidemiological evidence is limited, particularly for Mpumalanga Province. Understanding temporal, seasonal, and spatial patterns is essential for improving risk-based surveillance and control. Materials and methods A retrospective cross-sectional analysis was conducted using routine diagnostic records from the Mpumalanga Provincial Veterinary Laboratory between January 2021 and December 2024. Rose Bengal Test (RBT) results from cattle originating from 17 Local Municipality Areas (LMAs) were analysed. Annual, seasonal, and spatial seroprevalence estimates were calculated, and independent predictors of RBT seropositivity were evaluated using multivariable logistic regression. Results A total of 67,974 cattle serum samples were tested, of which 6,182 were RBT-positive, yielding an overall seroprevalence of 9.1% (95% CI: 8.9–9.3). Annual seroprevalence increased from 6.9% in 2021 to 7.4% in 2022, peaked at 13.1% in 2023, and declined to 7.5% in 2024. Clear seasonal variation was observed, with higher seroprevalence in spring (10.6%) and summer (10.2%) compared with autumn (6.8%) and winter (6.9%). Pronounced spatial heterogeneity was evident, with Emalahleni (13.3%), Victor Khanye (13.0%), and Mbombela (12.0%) identified as high-burden municipalities, while Mkhondo (1.7%) and Albert Luthuli (2.7%) recorded the lowest prevalence. In adjusted analyses, testing in 2023 was associated with nearly double the odds of seropositivity compared with 2021 (AOR 1.95; 95% CI: 1.81–2.11), and spring and summer remained significant predictors. Conclusion Bovine brucellosis in Mpumalanga exhibits marked temporal variability, seasonal peaks, and spatial clustering. These findings support targeted, risk-based surveillance, strategically timed vaccination, and strengthened biosecurity, prioritising hotspot municipalities and high-risk seasons within a One Health framework.引言 牛布鲁氏菌病（Bovine brucellosis）主要由流产布鲁氏菌（Brucella abortus）引起，仍是制约家畜生产性能的主要因素，同时持续构成人畜共患病威胁。尽管布鲁氏菌病在南非属于已得到管控的疾病，但次国家级的详实流行病学证据仍较为匮乏，尤以普马兰加省（Mpumalanga Province）为甚。明晰其时间、季节及空间分布模式，对于优化基于风险的监测与防控工作至关重要。 材料与方法 本研究基于2021年1月至2024年12月普马兰加省兽医实验室的常规诊断记录，开展回顾性横断面分析。研究对来自17个地方市政辖区（Local Municipality Areas, LMAs）的牛只虎红平板凝集试验（Rose Bengal Test, RBT）结果进行分析，计算了年度、季节及空间维度的血清阳性率估算值，并通过多变量逻辑回归模型评估了RBT血清阳性的独立预测因素。 结果 本研究共检测67974份牛血清样本，其中6182份RBT检测结果呈阳性，总血清阳性率为9.1%（95%置信区间：8.9–9.3）。年度血清阳性率从2021年的6.9%升至2022年的7.4%，2023年达到峰值13.1%，2024年回落至7.5%。研究观察到显著的季节变化特征：春季（10.6%）和夏季（10.2%）的血清阳性率显著高于秋季（6.8%）与冬季（6.9%）。空间异质性表现突出，埃马拉莱尼（Emalahleni，13.3%）、维克多·卡涅（Victor Khanye，13.0%）以及姆博姆贝拉（Mbombela，12.0%）被确定为高负担市辖区，而姆孔多（Mkhondo，1.7%）与阿尔伯特·卢图利（Albert Luthuli，2.7%）的阳性率最低。校正后分析显示，2023年的检测样本血清阳性比值比几乎为2021年的两倍（调整后比值比（Adjusted Odds Ratio, AOR）=1.95；95%置信区间：1.81–2.11），且春季、夏季仍为显著的预测因素。 结论 普马兰加省的牛布鲁氏菌病呈现出显著的时间变异性、季节高峰特征与空间聚集性。本研究结果支持在全健康（One Health）框架下，针对高风险市辖区与高风险季节开展靶向的基于风险的监测、策略性定时疫苗接种以及强化生物安全措施。