Objective To analyze the epidemiological characteristics of brucellosis in Chaoyang district, Beijing from 2016 to 2025, and provide evidence for the clinical diagnosis and treatment of brucellosis as well as epidemic prevention and control in large cities.

Method The incidence data of brucellosis in Chaoyang were collected from China Disease Prevention and Control Information System, epidemiological investigation reports of brucellosis cases and surveillance in key occupational populations from January 1, 2016 to December 31, 2025. Descriptive statistics were performed by using WPS 2023 and R 4.5.2. The seasonal distribution of the disease was analyzed by using seasonal index, concentration degree, and circular distribution methods. The spatial autocorrelation was analyzed with ArcGIS 10.8. Joinpoint regression and Mann-Kendall test was used to analyze temporal trends, and the annual percentage change (APC) was calculated.

Results A total of 749 brucellosis cases were reported by medical institutions in Chaoyang from 2016 to 2025, the cases were mainly men, aged 50−<70 years, and farmers. The incidence of brucellosis showed seasonal distribution, the cases mainly occurred during March - August. Meanwhile, a total of 65 cases were local residents in Chaoyang, they were mainly men, aged 50−<70 years, and the jobless/unemployed. No outbreaks occurred, and the cases were sporadic ones without significant spatial clustering (I=−0.02, Z=0.039, P=0.969). The annual incidence peak was around June 10. The consumption of undercooked beef or mutton was the main infection route (39.68%). Fever was the most common initial symptom (88.89%). The average delayed healthcare-seeking rate was 25.40%, with no significant temporal trend (Z=0.365, P=0.715). The average delayed diagnostic rate was 73.02%, showing a significant upward trend (Z=2.066, P=0.039, APC=11.67%).

Conclusion The incidence of brucellosis in Chaoyang showed a typical epidemiological characteristics: i.e. imported transmission, foodborne transmission, non-occupational infection and difficult clinical diagnosis. The diagnosis of brucellosis was often delayed with an increased rate. It is suggested to strengthen cross area joint prevention and control, foodborne risk management, collaboration between medical treatment and disease control, professional training, case surveillance and closed-loop management to promote early identification, standardized diagnosis and timely response for brucellosis.