Syphilis Among Female Sex Workers in Southwestern China: Potential for HIV Transmission YUHUA RUAN, PHD,* XIAOYUN CAO, MS,* HAN-ZHU QIAN, MD, PHD,† LI ZHANG, MS,* GUANGMING QIN, BS,‡ ZHENGQING JIANG,§ BENLI SONG,§ WEI HU,§ SHU LIANG, BS,† KANGLIN CHEN,§ YE YANG, MS,* XINXU LI, MS,* JUN WANG, MS,* XI CHEN, MS,* CHUN HAO, MS,* YANHUI SONG, MS,* HUI XING, MS,* NING WANG, MD, PHD,* AND YIMING SHAO, MD, PHD* Objective: The objective of this study was to investigate the prev- alence and risk factors of syphilis infection among female sex workers in a southwestern Chinese city along a drug trafficking route. Methods: From December 2004 to January 2005, 343 female sex workers (FSWs) were recruited through community outreach and peer referring. Confidential questionnaire interviews were adminis- tered to collect information on sexual and other sexually transmitted diseases/HIV risk behaviors. Cervical and blood samples were collected to test for syphilis and HIV antibodies and Neisseria gonorrhoeae infec- tion; Condyloma acuminatum infection was diagnosed clinically. Results: Of 343 FSWs, 15.7% were infected with syphilis. The prevalence of HIV, gonorrhea, and C. acuminatum was 0.6%, 2.0%, and 1.5%, respectively. The subtype of 2 HIV-1 infections was both CRF 07BC. Nearly 10% of FSWs reported using illicit drugs. Con- sistent use, inconsistent use, and never use of condoms with commer- cial sex clients in the last month were reported by 53.9%, 38.5%, and 7.6% FSWs, respectively. Longer duration of sex work (odds ratio [OR]  1.98; 95% confidence interval [CI]  1.08 –3.62), working at low-end establishments (OR  2.03; 95% CI  1.10 –3.76), and if primary sex partners had sex with other women in the past 6 months (OR  2.06; 95% CI  1.08 –3.91) were independently associated with syphilis infection. Conclusions: High prevalence of syphilis and overlapped unpro- tected commercial sex and drug using behaviors among FSWs along a drug-trafficking route may suggest a potential for rapid spread of HIV from injection drug users to FSWs and then to the general population and underscore the urgency of preventive interventions to break the bridge of FSWs for HIV/sexually transmitted disease spread. SINCE CHINA ADOPTED A FREE market economy and an open door policy in 1978, commercial sex activities have flourished across the country. The Chinese Public Security Office estimated that there are 4 to 6 million sex workers nationwide in 2000, an increase of 160-fold in number compared with 1985. 1 During this period, the annual cases of 8 reportable sexually transmitted dis- eases (STDs, including syphilis and HIV/AIDS) increased by 147-fold from 5838 to 859,040. 2 The skyrocketing STD epidemic is becoming an increasingly important public health problem in China. Furthermore, studies have shown several STDs may in- crease HIV susceptibility. Ulcerative diseases such as syphilis are more likely than nonulcerative ones such as Neisseria gonor- rhoeae and Chlamydia trachomatis infections to facilitate HIV transmission. 3,4 Syphilis is a common STD in China, which ac- counts for approximately 10% of the reported STD cases nation- wide, for example, 9.9% in 2000 and 10.9% in 2004. 2,5 Risk of HIV/AIDS in China is shifting from illegal plasma/ blood-collecting practices and injection drug use to sexual contacts. 1 Heterosexual transmission of HIV through female sex workers (FSWs) is of particular concern. National sentinel surveillance data showed that average prevalence of HIV among FSWs increased from 0.02% in 1996 to 0.93% in 2004. 6 Epidemiologic studies found a wide range of STD prevalence among FSWs, for example, HIV ranges from 0% to 10.3%. 7–10 Use of different sampling methods and geographic variation of HIV infection may explain the results. We conducted a community-based survey among FSWs in a southwestern Chinese city located on a drug-trafficking route, where HIV and syphilis infections are common among injection drug users (IDUs). 11–13 This article presents the prevalence of STDs with a focus on syphilis infection. Methods Study Design and Study Population This cross-sectional study was conducted between December 2004 and January 2005 in Xichang City, Sichuan Province, aiming to estimate baseline prevalence of HIV and other STDs among FSWs, describe their STD/HIV risk behaviors, and set up a cohort. Xichang City is located on a major drug-trafficking route. 13,14 Its total population is 617,000 and 10% are Yi minority people. Local This study was supported by grants from the Ministry of Science and Technology of China (2004BA719A01, 2004BA719A02), the Ministry of Health of China (WA2003-13), and the National Natural Science Founda- tion of China (30571612, 10501052). Correspondence: Yiming Shao, MD, PhD, State Key Laboratory for Infectious Disease Prevention and Control, and National Center for AIDS/ STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China., 27 Nanwei Road, Xuanwu District, Beijing 100050, China. E-mail: yshao@bbn.cn. Received for publication August 30, 2005, and accepted March 10, 2006. From the *State Key Laboratory for Infectious Disease Prevention and Control and the National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China; the †Division of Preventive Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; the ‡Sichuan Provincial Center for Disease Control and Prevention, Chengdu, Sichuan Province, China; and the §Xichang Center for STD and Leprosy Control, Xichang City Sichuan Province, China Sexually Transmitted Diseases, December 2006, Vol. 33, No. 12, p.719 –723 DOI: 10.1097/01.olq.0000218881.01437.99 Copyright © 2006, American Sexually Transmitted Diseases Association All rights reserved. 719