[Co-incidence of sexually transmitted diseases in female sex workers in Yunnan Province, 2023].

Objective: To investigate the co-infection status of HIV, Treponema pallidum (TP), Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and HCV in female sex workers (FSWs) in Yunnan Province in 2023, and provide evidence for the development of the prevention and intervention strategies for sexually transmitted diseases (STD). Methods: A cross-sectional study was conducted in FSWs in Yunnan from April to June 2023 in the form of face-to-face questionnaire survey, and biological samples were collected from the FSWs. Apriori algorithm was used for the association analysis rule on the co-infection patterns of HIV, TP, CT, NG, and HCV in the FSWs. Results: A total of 3 040 FSWs aged 16-65 years were surveyed, in whom 1 546 (50.85%) were married, 2 608 (85.79%) were local residents, 1 980 (65.13%) were in Han ethnic group, and 2 140 (70.40%) had education level of junior high school or below. The detection rates of HIV, TP, CT, NG, and HCV infections were 0.23% (7/3 040), 2.29% (69/3 040), 11.51% (350/3 040), 3.49% (106/3 040) and 0.39% (12/3 040), respectively. Analysis on the co-infection patterns revealed that the most common dual co-infection was CT+NG (1.51%).The most common triple co-infection was TP+CT+NG (0.16%). The only observed quadruple co-infection was TP+CT+NG+HCV (0.03%). The association rule analysis showed that the highest support was for CT+NG (1.51%). Confidence varied significantly depending on antecedent and consequent rules. Lift values indicated strong positive correlations among the most STD (all >1.00 except CT→HCV and HCV→CT, where lift <1.00). In the dual co-infections, NG and HIV had the strongest association (lift=8.19). As the number of co-infections increased, the likelihood of additional infections increased, reflecting stronger disease correlations. Conclusions: The co-incidence patterns of STDs in FSWs in Yunnan are complex, with CT, NG, and TP causing the most common co-infections. It is necessary to take an integrated measure of joint health education, testing, prevention, and treatment for multi diseases in the future.