María A. Pando

Diverse BF recombinants have spread widely since the introduction of HIV-1 into South America.

ObjectiveTo describe the genetic diversity of HIV-1 in South America by full genome sequencing and analysis. MethodsPurified peripheral blood mononuclear cell DNA from HIV-infected individuals in Argentina, Uruguay and Bolivia was used to amplify full HIV-1 genomes. These were sequenced using the ABI 3100 automated sequencer and phylogenetically analysed. ResultsTwenty-one HIV-1 strains from three South American countries, 17 of which were pre-screened by envelope heteroduplex mobility assay (HMA), were studied. Ten out of 10 HMA subtype F and four out of seven HMA subtype B strains were actually BF recombinants upon full genome analysis. Two BF recombinants from Argentina and two from Uruguay had the same structure, representing a new circulating recombinant form termed CRF12_BFARMA159. Twelve other BF recombinants had structures related to CRF12 but with additional segments of subtype B; each was unique. BF recombinants were temporally and geographically widespread, found as early as 1986–1987 in vertically infected Argentinian children and in Argentina, Uruguay, and Bolivia.

Two HIV-1 epidemics in Argentina: different genetic subtypes associated with different risk groups.

Summary: This study determined the risk behaviors and viral subtypes of HIV‐1 found in 134 heterosexual HIV‐seroprevalent maternity patients, 41 of their sexual partners (men who have sex with women [MSW]), and 95 homosexual men (men who have sex with men [MSM]) from Buenos Aires, Argentina. Peripheral blood mononuclear cells (PBMCs) were purified from blood and used for DNA extraction, amplification, and genotyping by the envelope heteroduplex mobility assay (env HMA). Most of the women had been infected by having sex with an already infected partner (84%), whereas most of the male partners had been infected via drug use (76%). Both the patients and their sexual partners were poorly educated, only 30% having completed secondary school. The MSM study subjects, however, were significantly better educated and had a lower prevalence of injecting drug use. Env HMA subtype F was found in 77% (103 of 134) of the maternity patients, with similar rates in their partners (73%). Most of the remaining samples were env subtype B. All but one of the couples was concordant in subtype. In the MSM risk group, however, only 10% were env HMA subtype F. Ninety percent of the MSM samples were subtype B. There are at least two independent epidemics of HIV‐1 infection in Buenos Aires, Argentina. One, in heterosexual men and women, is dominated by env subtype F whereas the other, in homosexual men, is dominated by env subtype B, as determined by env HMA.

First report on sexually transmitted infections among trans (male to female transvestites, transsexuals, or transgender) and male sex workers in Argentina: high HIV, HPV, HBV, and syphilis prevalence

OBJECTIVES Due to the scarce data on the prevalence of sexually transmitted infections (STIs) among male-to-female trans-sex workers (TSW) and male sex workers (MSW) in Argentina, the present study aimed to estimate the incidence of human immunodeficiency virus (HIV), and the prevalence of HIV, hepatitis B virus (HBV), hepatitis C virus (HCV), and Treponema pallidum. Human papillomavirus (HPV) and Chlamydia trachomatis infections were tested among TSW. METHODS Two hundred and seventy-three TSW and 114 MSW were recruited by nongovernmental organizations. HIV incidence was estimated by STARHS (serologic testing algorithm for recent HIV seroconversion). HPV and C. trachomatis infections were tested in anal cells from TSW. RESULTS TSW showed significantly higher prevalences of HIV (34.1 vs. 11.4%), HBV (40.2 vs. 22.0%), and T. pallidum (50.4 vs. 20.4%) than MSW. TSW tested positive for HPV in 111/114 cases and for C. trachomatis in 4/80 cases. Investigation of HBV, HCV, HIV, and T. pallidum co-infections showed that 72% of TSW and 39% of MSW had at least one STI. T. pallidum was the most frequent mono-infection. The estimated HIV incidence was 10.7 per 100 person-years (95% confidence interval (CI) 3.8-17.7) for TSW and 2.3 per 100 person-years (95% CI 0-6.7) for MSW. CONCLUSIONS The high prevalence of STIs and the high incidence of HIV demonstrate the great vulnerability of these high-risk populations and indicate the urgent need for preventive strategies on intervention and facilitation of access to healthcare programs.

Violence as a Barrier for HIV Prevention among Female Sex Workers in Argentina

Background Violence against female sex workers (FSWs) has been increasingly reported as an important determinant of HIV infection risk. This study explores the frequency of different violent experiences (sexual abuse, rejection, beating and imprisonment) among FSWs in Argentina and its association with condom use and HIV and T. pallidum prevalence. Methods A convenience sample of 1255 FSWs was included in a cross-sectional study conducted between October 2006 and November 2009. Results Sexual abuse was reported by 24.1% (219/907) of women. A total of 34.7% (42/1234) reported rejection experiences, 21.9% (267/1215) reported having been beaten and 45.4% (561/1236) stated having been arrested because of their sex work activity. There was a higher frequency of inconsistent condom use with clients among FSWs who had experienced sexual abuse, rejection, and police detention. A higher frequency of HIV and T. pallidum infection was detected among FSWs who reported having been arrested by the police. Conclusion The study shows for the first time the frequency of different violent situations among FSWs in Argentina. The association between violence against sex workers, condom use and STI prevalence demonstrated here calls for measures to reduce stigma and violence against FSWs. Such violent experiences may increase vulnerability to STI through coerced unprotected sex.

Buenos Aires cohort of men who have sex with men: prevalence, incidence, risk factors, and molecular genotyping of HIV type 1.

The prevalence, incidence, risk factors, and molecular genotyping of HIV-1 infection among men who have sex with men (MSM) were assessed through a prospective cohort study. The study was conducted in Buenos Aires from February 2003 to December 2004. Sociodemographic, sexual risk behavior data, and blood samples for HIV testing were collected at baseline and at 6 and 12 months. Cox regression analysis was applied to determine risk factors associated with HIV seroconversion. HIV-positive samples were analyzed by partial (pro/RT) and full-length genome sequencing. Of 811 HIV-negative participants evaluated at baseline, 327 volunteers that fulfilled the inclusion criteria were enrolled. Retention rates at 6 and 12 months were 97.2% and 91.5%, respectively. Twelve MSM seroconverted for HIV infection [incidence rate = 3.9 (95% CI = 2.0-6.7) per 100 person-years]. HIV seroconversion was associated with a greater number of different sexual contacts in the preceding 6 months (> or =10, hazard ratio = 3.3, 95% CI: 1.1-10.4). By partial pro/RT genotyping analysis, 83% HIV-positive samples were subtype B and 17% samples were BF recombinants, most of these being unique recombinant forms. This study describes for the first time the recruitment and follow-up of a cohort of MSM in Argentina. Retention rates and HIV incidence rate were high. These data should be considered as a promising potential population for HIV vaccine trials.

HIV and Other Sexually Transmitted Infections among Men Who Have Sex with Men Recruited by RDS in Buenos Aires, Argentina: High HIV and HPV Infection

Background The aim of this study was to estimate the prevalence of HIV and other STIs, among MSM from Buenos Aires (2007–2009). Methods Responding Driven Sampling was used for recruitment of MSM. Participants completed a structured web-based survey and provided biological samples. Results A total of 496 MSM were studied for HIV, HBV, HCV, and T pallidum infections. Chlamydia and HPV diagnoses were only performed in 98 and 109 participants, respectively. Prevalence of HIV was 17.3%, HBV 22.9%, HCV 7.5%, T pallidum 20.5%, HPV 83.5%, and C trachomatis 1.7%. In the year prior to the evaluation, 71% of the participants had had sex with men and/or trans and women (MMW) while 29% had not had sex with women (MM). Comparing MM to MMW, prevalence of HIV (30.7% vs. 11.9%, p<0.001), HBV (36.4% vs. 17.8%, p<0.001), T pallidum (32.1% vs. 15.7%, p<0.001), and HPV (88.3% vs. 70.4%, p = 0.039) were significantly higher among MM, whereas no significant differences were found for HCV and C trachomatis. The MM group had also significantly higher HIV incidence (5.60 vs. 4.28 per 100 persons-year, p = 0.032). HPV genotypes 16, 6, and 11 were the most frequently found; 40.7% of the MSM had more than one genotype and one high risk genotype was detected in 43.6% of participants. Conclusions Both MM and MMW are at high risk of infection for HIV and other STIs. Rates of HIV, HBV, T pallidum and HPV infections are higher in the MM group.

Use of Respondent Driven Sampling (RDS) Generates a Very Diverse Sample of Men Who Have Sex with Men (MSM) in Buenos Aires, Argentina

Background Prior research focusing on men who have sex with men (MSM) conducted in Buenos Aires, Argentina, used convenience samples that included mainly gay identified men. To increase MSM sample representativeness, we used Respondent Driven Sampling (RDS) for the first time in Argentina. Using RDS, under certain specified conditions, the observed estimates for the percentage of the population with a specific trait are asymptotically unbiased. We describe, the diversity of the recruited sample, from the point of view of sexual orientation, and contrast the different subgroups in terms of their HIV sexual risk behavior. Methodology 500 MSM were recruited using RDS. Behavioral data were collected through face-to-face interviews and Web-based CASI. Conclusion In contrast with prior studies, RDS generated a very diverse sample of MSM from a sexual identity perspective. Only 24.5% of participants identified as gay; 36.2% identified as bisexual, 21.9% as heterosexual, and 17.4% were grouped as “other.” Gay and non-gay identified MSM differed significantly in their sexual behavior, the former having higher numbers of partners, more frequent sexual contacts and less frequency of condom use. One third of the men (gay, 3%; bisexual, 34%, heterosexual, 51%; other, 49%) reported having had sex with men, women and transvestites in the two months prior to the interview. This population requires further study and, potentially, HIV prevention strategies tailored to such diversity of partnerships. Our results highlight the potential effectiveness of using RDS to reach non-gay identified MSM. They also present lessons learned in the implementation of RDS to recruit MSM concerning both the importance and limitations of formative work, the need to tailor incentives to circumstances of the less affluent potential participants, the need to prevent masking, and the challenge of assessing network size.

Incidence of HIV Type 1 Infection, Antiretroviral Drug Resistance, and Molecular Characterization in Newly Diagnosed Individuals in Argentina: A Global Fund Project

An HIV incidence estimation was performed among men who have sex with men (MSM), drug users (DUs), sex workers (SWs), and pregnant women (PW) from Argentina. Volunteers older than 18 years old without a previous HIV-positive diagnosis were included. HIV-positive samples were analyzed by the Serological Testing Algorithm for Recent HIV Seroconversion (STARHS) to estimate incidence. By partial RT-PCR and sequencing of the HIV pol gene, an HIV subtype and resistance profile were determined. A total of 12,192 volunteers were recruited from October 2006 to September 2008. A higher HIV prevalence was detected among trans SWs (33.9%, 38/112), male SWs (10.8%, 12/111), and MSM 10.4% (161/1549). HIV incidence estimates by STARHS was also higher on trans SWs (11.31 per 100 person-years), male SWs (6.06 per 100 person-years), and MSM (6.36 per 100 person-years). Antiretroviral primary resistant mutations were detected in 8.4% of the study group, with a higher frequency in female DUs (33.3%). Phylogenetic analysis showed that 124 (57.9%) samples were subtype B, 84 (39.3%) intersubtype BF recombinants, 5 (2.3%) subtype C, and 1 (0.5%) subtype F in the pol region. Subtype B was most commonly found in MSM and male SWs whereas the intersubtype BF recombinant was more prevalent in female DUs, female SWs, and PW. Given the high HIV prevalence and incidence found in most of these groups, monitoring the continuing spread of the HIV epidemic is essential for determining public health priorities, assessing the impact of interventions, and estimating current and future health care needs.

Early Gag Immunodominance of the HIV-Specific T-Cell Response during Acute/Early Infection Is Associated with Higher CD8+ T-Cell Antiviral Activity and Correlates with Preservation of the CD4+ T-Cell Compartment

ABSTRACT The important role of the CD8+ T-cell response on HIV control is well established. Moreover, the acute phase of infection represents a proper scenario to delineate the antiviral cellular functions that best correlate with control. Here, multiple functional aspects (specificity, ex vivo viral inhibitory activity [VIA] and polyfunctionality) of the HIV-specific CD8+ T-cell subset arising early after infection, and their association with disease progression markers, were examined. Blood samples from 44 subjects recruited within 6 months from infection (primary HIV infection [PHI] group), 16 chronically infected subjects, 11 elite controllers (EC), and 10 healthy donors were obtained. Results indicated that, although Nef dominated the anti-HIV response during acute/early infection, a higher proportion of early anti-Gag T cells correlated with delayed progression. Polyfunctional HIV-specific CD8+ T cells were detected at early time points but did not associate with virus control. Conversely, higher CD4+ T-cell set points were observed in PHI subjects with higher HIV-specific CD8+ T-cell VIA at baseline. Importantly, VIA levels correlated with the magnitude of the anti-Gag cellular response. The advantage of Gag-specific cells may result from their enhanced ability to mediate lysis of infected cells (evidenced by a higher capacity to degranulate and to mediate VIA) and to simultaneously produce IFN-γ. Finally, Gag immunodominance was associated with elevated plasma levels of interleukin 2 (IL-2) and macrophage inflammatory protein 1β (MIP-1β). All together, this study underscores the importance of CD8+ T-cell specificity in the improved control of disease progression, which was related to the capacity of Gag-specific cells to mediate both lytic and nonlytic antiviral mechanisms at early time points postinfection.

Epidemiology of human immunodeficiency virus viral hepatitis (B and C) Treponema pallidum and human T-cell lymphotropic I / II virus among men who have sex with men in Buenos Aires Argentina.

Background: Human immunodeficiency virus (HIV) and sexually transmitted infections (STI) are prevalent among men who have sex with men (MSM). Goal: To estimate the prevalence of HIV and STIs in this group. Study: A total of 694 MSM were tested for HIV, hepatitis B (HBV), hepatitis C (HCV), human T-cell lymphotropic (HTLV-I/II) viruses and Treponema pallidum infection. Results: HIV, HBV, and T pallidum were detected in 13.8%, 37.7%, and 16.9% of subjects, respectively. Prevalences of 1.9% and 0.3% were detected for HCV and HTLV-I/II. A prior history of STI was the most predictor for HIV, HBV, and T pallidum. Use of illegal drugs, blood transfusion history, and multiple sexual partners were associated with HCV. The 2 most common coinfections were HBV/T pallidum and HIV/HBV. Conclusions: Infection with HIV, HBV, and T pallidum was elevated among MSM. Routine testing, education, vaccine-based prevention, and control programs need to be implemented in this high-risk population.