Background: The Estudio Multicéntrico (EMC) introduced standardized second-generation sentinel surveillance to the Central America where several countries had scant prior epidemiological information, particularly regarding men who have sex with men (MSM). The goal was to ascertain prevalence of sexually transmitted infections, including HIV infection (and HIV seroincidence), and their associated socio-behavioral risks.
Methods:  In 2000 to 2001, using convenience sampling in 6 large cities in El Salvador, Guatemala, Honduras, Nicaragua, and Panama, we recruited 1418 MSM. Eligible and consenting self-identified MSM participated in this cross-sectional study and underwent clinical examination, face-to-face interviews, and serologic testing for HIV and HSV-2 infections and syphilis, and polymerase chain reaction (PCR) tests for Chlamydia trachomatis and Neisseria gonorrhoeae. HIV seroincidence was estimated based on results of the BED capture enzyme immunoassay (CEIA).
Results:  Seroprevalences of HIV across the 6 cities ranged from 15.5% in San Pedro Sula and 15.3% in San Salvador to 7.6% in Managua and 7.5% in Nicaragua but seroincidence estimates were highest in Managua and San Pedro Sula (14.4 and 8.3/100 person-years, respectively). HSV-2 seropositivity was found in 48.2% of 737 MSM and varied little by city. By multivariate analysis, HIV infection was independently associated with age older than 25 (OR 1.9, 95%CI 1.4 to 3.1), having sex work experience (OR 1.8, 95%CI 1.1 to 3.1), and with greater number of male partners (OR 1.2, 95%CI 1.0 to 1.5; p = 0.06). When we added sexually transmitted co-infection to the model, there was little change in these associations, and HSV-2 infection and syphilis seropositivity were each independently positively associated with HIV infection (OR 4.4, 95%CI 2.3 to 8.6 and OR 2.5, 95%CI 1.2 to 5.0, respectively). A behavioral risk profile revealed variations in condom use patterns and bridging (unprotected sex with females) by sexual self-identity category. Correlates of HSV-2 infection will also be presented.
Conclusions: This study highlights the considerable epidemiological vulnerability of MSM in Central America, including the substantially higher existing burden of HIV infection than in female sex workers in each corresponding country, except Honduras. This pattern is similar to that documented for other areas of Latin America. The role ulcerative sexually transmitted infections can have in HIV risk is also mirrored in these data. Behavioral risk descriptions are useful for targeted intervention design.