Mexico's northern border conflict: collateral damage to health and human rights of vulnerable groups.

Objective: To compare distributions of human rights violations and disease risk; to juxtapose these patterns against demographic and structural environmental variables, and to formulate implications for structural interventions.

Methods: Female sex workers who inject drugs were surveyed in Tijuana and Ciudad Juarez, Mexico. Structured interviews and testing for sexually transmitted infections (STIs) were conducted (October 2008 to October 2009). Frequencies of individual and environmental factors, including police abuse, risk of HIV infection, and protective behaviors, were compared between sites using univariate logistic regression.

Results: Of 624 women, almost half reported police syringe confiscation despite syringes being legal; 55.6% reported extortion (past 6 months), with significantly higher proportions in Ciudad Juarez (P < 0.001). Reports of recent solicitation of sexual favors (28.5% in Tijuana, 36.5% in Ciudad Juarez, P = 0.04) and sexual abuse (15.7% in Tijuana, 18.3% in Ciudad Juarez) by police were commonplace. Prevalence of STIs was significantly lower in Tijuana than in Ciudad Juarez (64.2% and 83.4%, P < 0.001), paralleling the lower prevalence of sexual risk behaviors there. Ciudad Juarez respondents reported significantly higher median number of monthly clients (6.8 versus 1.5, P < 0.001) and lower median pay per sex act (US$ 10 versus US$ 20, P < 0.001) (in the past month). Relative to Tijuana, security deployment, especially the army's presence, was perceived to have increased more in Ciudad Juarez in the past year (72.1% versus 59.2%, P = 0.001).

Conclusions: Collateral damage from police practices in the context of Mexico's drug conflict may affect public health in the Northern Border Region. Itinerant officers may facilitate disease spread beyond the region. The urgency for mounting structural interventions is discussed.