Abstract: Objective To analyze the epidemiological characteristics of syphilis in Nankai District of Tianjin City,and provide a basis for the prevention and treatment of venereal diseases. Methods Based on the data of the Chinese Disease Prevention and Control Information System,the incidence and composition ratio of the report were calculated by descriptive statistical methods,and the Chi-square test was used to compare the rates and the change trend was analyzed by the trend Chi-square test,to analyze the report of syphilis cases in Nankai District of Tianjin City from 2008 to 2022. Results From 2008 to 2022,a total of 4 844 syphilis cases were reported in Nankai District of Tianjin City,with an average annual reported incidence rate of 29.83/100 000. The reported cases of syphilis showed an overall downward trend,from 40.54/100 000 in 2008 to 23.45/100 000 in 2022（χ²_trend= 69.858,P<0.01）,of which primary and secondary syphilis decreased year by year,with an average annual decrease of 12.01% and 17.07%,respectively,but the incidence of hidden syphilis increased year by year,from 10.94/100 000 to 20.27/100 000（χ²_trend= 212.834,P<0.01）,with an average annual increase of 3.84%. There were reports of syphilis cases in Nankai District every month of the year,with the fewest cases in February and a small peak in March. The cases were mainly concentrated from July to September,with a total of 1 386 cases,accounting for 28.61%. Among the reported cases of syphilis,2 642 cases（54.54%） were male,the incidence rate was 32.15/100 000,and 2 202 cases（45.46%） were female,the incidence rate was 27.46/100 000. The reported cases were mainly concentrated in the population aged ≥ 20 years old,with the highest number of cases aged 20-<30 years old,accounting for 1 273 cases（26.28%）,and the incidence rate of all age groups aged <50 years showed a downward trend year by year,while the incidence rate in the ≥60 year-old age group showed an increasing trend,from 28.49/100 000 in 2008 to 35.04/100 000 in 2022（χ²_trend=15.399,P<0.01）.The occupational distribution of syphilis reported cases was mainly domestic work and unemployed,retired people,and commercial service personnel. The distribution of reported cases in the department of dermatology（venereal diseases） was the largest,with 331 cases（32.77%）. Conclusion The incidence of syphilis in Nankai District of Tianjin City is generally on the decline,but the situation of syphilis prevention and control is still serious. It is suggested to combine syphilis prevention and control with AIDS prevention and control to carry out comprehensive prevention and control.

Key words: Syphilis, Reported cases, Epidemiological characteristics