BackgroundFSWs who inject drugs (FSW-IDUs) can acquire HIV through high risk sexual and injection behaviors. We studied correlates of HIV infection among FSW-IDUs in northern Mexico, where sex work is quasi-legal and syringes can be legally obtained without a prescription.MethodsFSW-IDUs>18 years old who reported injecting drugs and recent unprotected sex with clients in Tijuana and Ciudad Juarez underwent surveys and HIV/STI testing. Logistic regression identified correlates of HIV infection.ResultsOf 620 FSW-IDUs, prevalence of HIV, gonorrhea, Chlamydia, trichomonas, syphilis titers ≥1∶8, or any of these infections was 5.3%, 4%, 13%, 35%, 10% and 72%, respectively. Compared to other FSW-IDUs, HIV-positive women were more likely to: have syphilis titers ≥1∶8 (36% vs. 9%, p<0.001), often/always inject drugs with clients (55% vs. 32%, p = 0.01), and experience confiscation of syringes by police (49% vs. 28%, p = 0.02). Factors independently associated with HIV infection were syphilis titers ≥1∶8, often/always injecting with clients and police confiscation of syringes. Women who obtained syringes from NEPs (needle exchange programs) within the last month had lower odds of HIV infection associated with active syphilis, but among non-NEP attenders, the odds of HIV infection associated with active syphilis was significantly elevated.ConclusionsFactors operating in both the micro-social environment (i.e., injecting drugs with clients) and policy environment (i.e., having syringes confiscated by police, attending NEPs) predominated as factors associated with risk of HIV infection, rather than individual-level risk behaviors. Interventions should target unjustified policing practices, clients' risk behaviors and HIV/STI prevention through NEPs.

Objective: To characterize the overlap between injection drug use and sex work by women in Tijuana and Cd. Juarez, situated on the Mexico-U.S. border. Methods:FSWs aged ≥18 years who were not knowingly HIV-positive and reported having unprotected sex with ≥1 client in the prior two months underwent interviews and testing for HIV, syphilis gonorrhea and Chlamydia. Logistic regression identified factors associated with injecting drugs within the last month.Results: Of 924 FSWs, 18.0% had ever injected drugs. Among FSW-IDUs (N=114), prevalence of HIV, syphilis titers >1:8, gonorrhea and Chlamydia was significantly higher at 12.3%, 22.7%, 15.2% and 21.2% compared to 4.8%, 13.1%, 5.2% and 11.9% among other FSWs (N=810). FSWIDUs also had more clients in the past six months (median: 300 vs. 240, p=0.02). Factors independently associated with injecting drugs in the past month included living in Tijuana, being younger, being married/common-law, longer duration in the sex trade, speaking English, earning Corresponding Author and Reprint Requests: Thomas L. Patterson, PhD Department of Psychiatry (0680) University of California, San Diego 9500 Gilman Drive La Jolla, CA 92093-0680 Phone: 858-534-3354; Fax: 858-534-7723 E-mail: tpatterson@ucsd.edu. Contributors Drs. Patterson and Semple designed the behavioral intervention study (NIMH R01 MH065849), supervised data collection, and contributed to manuscript writing. Dr. Strathdee planned the analysis, assisted with interpreting results, and wrote the majority of the manuscript. Ms. Philbin and Ms. Pu conducted the analyses and assisted with interpreting results and writing the manuscript. Drs. de la Torre, Amaro, Magis, Salazar assisted with study design and interpreting results and revising the manuscript. Drs. Lozada, Staines, Martinez and Fraga supervised data collection and assisted with the manuscript. Ms. Orozovich supervised data collection and provided oversight of the intervention study. All authors contributed to and have approved the final manuscript. Conflict of InterestThe authors have no conflicts of interest to disclose.Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Conclusions: FSW-IDUs had higher STI levels, engaged in riskier behaviors and were more vulnerable to having unsafe sex with clients compared to other FSWs, indicating that this subgroup is an important bridge population requiring focused prevention. NIH Public Access

Objective To examine efficacy of a brief behavioral intervention to promote condom use among female sex workers (FSWs) in two Mexico-U.S. border cities. Methods 924 FSWs aged ≥18 years without known HIV infection living in Tijuana and Ciudad Juarez having recent unprotected sex with clients were randomized to a 30 minute behavioral intervention integrating motivational interviewing and principles of behavior change, or a didactic control condition. At baseline and six months, women underwent interviews and testing for HIV, syphilis, gonorrhea and chlamydia. Results Comparing intervention versus control groups, we observed a 40% decline in cumulative STI incidence (p=0.049). Incidence density for the intervention vs. control was 13.8 vs 24.92 per 100 person years (py) for STIs combined (p=0.034), and 0 vs. 2.01 per 100 py for HIV (p<0.001), with concomitant increases in total numbers and percentages of protected sex acts and decreases in total numbers of unprotected sex acts with clients (p<0.05). Conclusions This brief behavioral intervention shows promise in reducing HIV/STI risk behaviors among FSWs in two Mexican-U.S border cities, and may be transferable to other resource-constrained settings.

Objective-We examined correlates of HIV infection among injection drug users (IDUs) in Tijuana, Mexico, a city bordering the United States, which is situated on major migration and drug trafficking routes.Methods-IDUs aged ≥18 years were recruited using respondent-driven sampling. Participants underwent antibody testing for HIV and syphilis and structured interviews. Weighted logistic regression identified correlates of HIV infection.Results-Of 1056 IDUs, the median age was 37 years, 86% were male, and 76% were migrants. HIV prevalence was higher in female participants than in male participants (8% vs. 3%; P = 0.01). Most IDUs testing HIV-positive were previously unaware of their serostatus (93%). IDUs reported injecting with a median of 2 people in the prior 6 months and had been arrested for having injection stigmata (ie, "track-marks") a median of 3 times. Factors independently associated with HIV infection were being female, syphilis titers consistent with active infection, larger numbers of recent injection partners, living in Tijuana for a shorter duration, and being arrested for having track-marks.Conclusions-Individual, social, and environmental factors were independently associated with HIV infection among IDUs in Tijuana. These findings suggest the need to intervene not solely on individual risk behaviors but on social processes that drive these behaviors, including problematic policing practices. Policing practices may have a significant impact on IDUs' ability to adhere to safe injection practices, thereby influencing their risk of acquiring HIV. Qualitative evidence shows that local policing practices influence how, where, and under what circumstances IDUs obtain and use injection equipment. 28,[30][31][32][33][34] Disruptions to IDUs' risk reduction practices and engagement in HIV risk behavior have been linked to high-visibility policing and fear of arrest or detainment, 30 which exacerbates withdrawal symptoms. Quantitative studies report that aggressive policing practices are associated with higher levels of needle sharing [35][36][37][38] and lower utilization of syringe exchange programs (SEPs). 39,40 In an ecologic study of the macrolegal environment in 89 metropolitan areas in the United States, Friedman and colleagues 41 showed that higher levels of legal repressiveness were positively associated with HIV prevalence among IDUs. Studies are lacking to determine how such effects interplay alongside individual and social network factors. KeywordsMobility is emerging as an important risk factor in the transmission dynamics of communicable diseases, including HIV. [42][43][44][45] Migration and mobility are associated with family separation, disintegration of social networks, sudden changes in the cultural environment, homelessness, poverty, social isolation, and a greater sense of anonymity, which may enable riskier behaviors. [46][47][48][49][50] In one study, social pressures, including legal problems, entering drug treatment, and the It is legal to purchase or carry syringes without ...

Culturally appropriate interventions are needed to identify and treat ulcerative sexually transmitted infections and reduce HIV risks associated with stimulants among FSWs in the Mexico-US border region.

BackgroundWe evaluated brief combination interventions to simultaneously reduce sexual and injection risks among female sex workers who inject drugs (FSW-IDUs) in Tijuana and Ciudad Juarez, Mexico during 2008–2010, when harm reduction coverage was expanding rapidly in Tijuana, but less so in Juarez.MethodsFSW-IDUs ≥18 years reporting sharing injection equipment and unprotected sex with clients within the last month participated in a randomized factorial trial comparing four brief, single-session conditions combining either an interactive or didactic version of a sexual risk intervention to promote safer sex in the context of drug use, and an injection risk intervention to reduce sharing of needles/injection paraphernalia. Women underwent quarterly interviews and testing for HIV, syphilis, gonorrhea, Chlamydia and Trichomonas, blinding interviewers and assessors to assignment. Poisson regression with robust variance estimation and repeated measures ordinal logistic regression examined effects on combined HIV/STI incidence and receptive needle sharing frequency.FindingsOf 584 initially HIV-negative FSW-IDUs, retention was ≥90%. After 12 months, HIV/STI incidence decreased >50% in the interactive vs. didactic sex intervention (Tijuana:AdjRR:0.38,95% CI:0.16–0.89; Juarez: AdjRR:0.44,95% CI:0.19–0.99). In Juarez, women receiving interactive vs. didactic injection risk interventions decreased receptive needle-sharing by 85% vs. 71%, respectively (p = 0.04); in Tijuana, receptive needle sharing declined by 95%, but was similar in active versus didactic groups. Tijuana women reported significant increases in access to syringes and condoms, but Juarez women did not.InterpretationAfter 12 months in both cities, the interactive sexual risk intervention significantly reduced HIV/STI incidence. Expanding free access to sterile syringes coupled with brief, didactic education on safer injection was necessary and sufficient for achieving robust, sustained injection risk reductions in Tijuana. In the absence of expanding syringe access in Juarez, the injection risk intervention achieved significant, albeit more modest reductions, suggesting that community-level interventions incorporating harm reduction are more powerful than individual-level interventions.Trial Registrationclinicaltrials.gov NCT00840658

HIV prevalence is rising, especially among high risk females in Tijuana, Baja California, a Mexico-US border city situated on major migration and drug trafficking routes. We compared factors associated with HIV infection among male and female injection drug users (IDUs) in Tijuana in an effort to inform HIV prevention and treatment programs. IDUs aged ≥18 years were recruited using respondent-driven sampling and underwent testing for HIV, syphilis and structured interviews. Logistic regression identified correlates of HIV infection, stratified by gender. Among 1056 IDUs, most were Mexican-born but 67% were born outside Tijuana. Reasons for moving to Tijuana included deportation from the US (56% for males, 29% for females), and looking for work/better life (34% for females, 15% for males). HIV prevalence was higher in females versus males (10.2% vs. 3.5%, p = 0.001). Among females (N = 158), factors independently associated with higher HIV prevalence included younger age, lifetime syphilis infection and living in Tijuana for longer durations. Among males (N = 898), factors independently associated with higher HIV prevalence were syphilis titers consistent with active infection, being arrested for having ‘track-marks’, having larger numbers of recent injection partners and living in Tijuana for shorter durations. An interaction between gender and number of years lived in Tijuana regressed on HIV infection was significant (p = 0.03). Upon further analysis, deportation from the U.S. explained the association between shorter duration lived in Tijuana and HIV infection among males; odds of HIV infection were four-fold higher among male injectors deported from the US, compared to other males, adjusting for all other significant correlates (p = 0.002). Geographic mobility has a profound influence on Tijuana's evolving HIV epidemic, and its impact is significantly modified by gender. Future studies are needed to elucidate the context of mobility and HIV acquisition in this region, and whether US immigration policies adversely affect HIV risk.

Respondent-driven sampling (RDS), a chain referral sampling approach, is increasingly used to recruit participants from hard-to-reach populations, such as injection drug users (IDUs). Using RDS, we recruited IDUs in Tijuana and Ciudad (Cd.) Juá rez, two Mexican cities bordering San Diego, CA and El Paso, TX, respectively, and compared recruitment dynamics, reported network size, and estimates of HIV and syphilis prevalence. Between February and April 2005, we used RDS to recruit IDUs in Tijuana (15 seeds, 207 recruits) and Cd. Juá rez (9 seeds, 197 recruits), Mexico for a cross-sectional study of behavioral and contextual factors associated with HIV, HCV and syphilis infections. All subjects provided informed consent, an anonymous interview, and a venous blood sample for serologic testing of HIV, HCV, HBV (Cd. Juá rez only) and syphilis antibody. Log-linear models were used to analyze the association between the state of the recruiter and that of the recruitee in the referral chains, and population estimates of the presence of syphilis antibody were obtained, correcting for biased sampling using RDS-based estimators. Sampling of the targeted 200 recruits per city was achieved rapidly (2 months in Tijuana, 2 weeks in Cd. Juá rez). After excluding seeds and missing data, the sample prevalence of HCV, HIV and syphilis were 96.6, 1.9 and 13.5% respectively in Tijuana, and 95.3, 4.1, and 2.7% respectively in Cd. Juá rez (where HBV prevalence was 84.7%). Syphilis cases were clustered in recruitment trees. RDS-corrected estimates of syphilis antibody prevalence ranged from 12.8 to 26.8% in Tijuana and from 2.9 to 15.6% in Ciudad Juá rez, depending on how recruitment patterns were modeled, and assumptions about how network size affected an individual_s probability of being included in the sample. RDS was an effective method to rapidly recruit IDUs in these cities. Although the frequency of HIV was low, syphilis prevalence was high, particularly in Tijuana. RDS-corrected estimates of syphilis prevalence were sensitive to model assumptions, suggesting that further validation of RDS is necessary.