Longitudinal characterization of HIV-1 pol-gene in treatment-naïve men-who-have-sex-with-men from acute to chronic infection stages.

HIV-1 is characterized by its ability to mutate and recombine even at polymerase (pol) gene. However, pol-gene diversity is limited due to functional constraints. The aim of this study was to characterize longitudinally, by next-generation sequencing (NGS), HIV-1 variants based on pol-gene sequences, at intra- and inter-host level, from acute/early to chronic stages of infection, in the absence of antiretroviral therapy. Ten men who have sex with men (MSM) were recruited during primary infection and yearly followed for five years. Even after a maximum of a five-year follow-up period, the phylogenetic analysis of HIV-1 pol-gene sequences showed a host-defined structured pattern, with a predominance of purifying selection forces during the follow-up. MSM had been acutely infected by different HIV-1 variants mainly ascribed to pure subtype B, or BF recombinant variants and showed different genetic mosaicism patterns that last until the chronic stage, representing a major challenge for prevention strategies.

In vivo drug resistance mutation dynamics from the early to chronic stage of infection in antiretroviral-therapy-naïve HIV-infected men who have sex with men.

Human immunodeficiency virus type 1 (HIV) primary drug resistance mutations (DRMs) influence the long-term therapeutic effects of antiretroviral treatment (ART). Drug-resistance genotyping based on polymerase gene sequences obtained by next-generation sequencing (NGS) was performed using samples from 10 ART-naïve HIV-infected men who have sex with men (MSM; P1-P10) from the acute/early to chronic stage of infection. Three of the 10 subjects exhibited the presence of major (abundance, ≥ 20%) viral populations carrying DRM at early/acute stage that later, at the chronic stage, dropped drastically (V106M) or remained highly abundant (E138A). Four individuals exhibited additional DRMs (M46I/L; I47A; I54M, L100V) as HIV minority populations (abundance, 2-20%) that emerged during the chronic stage but ephemerally.

High Substance Use and HIV Risk Behavior Among Young Argentine Men Who Have Sex with Men.

In the United States young men who have sex with men have higher rates of substance use, higher HIV incidence, and less frequent HIV testing than their heterosexual counterparts and older MSM. Less is known about comparable populations in Latin America. As part of an epidemiological study, MSM were recruited through Respondent Driven Sampling in the metropolitan area of Buenos Aires, Argentina and answered a computerized behavioral survey. From the total of 500 MSM enrolled, a sub-sample of 233 aged 18-25 was analyzed. The sample was concentrated among lower socioeconomic strata, and only 16% identified as gay. Nearly half reported male, female, and transvestite sexual partners. Reported substance use was widespread ranging from 61% for marijuana to 20% for pasta base (cocaine sulfate). Seventy percent of the sample had never been tested for HIV infection; 3% tested positive for HIV and 8% for syphilis during the study.

Genomic characterization and molecular evolution analysis of subtype B and BF recombinant HIV-1 strains among Argentinean men who have sex with men reveal a complex scenario.

Currently, data on HIV-1 circulating strains among men who have sex with men (MSM) in Argentina is scarce. In South America, the distribution and the prevalence of BF recombinants are dissimilar and exhibit an underappreciated heterogeneity of recombinant structures. Here, we studied for the first time the genetic diversity of HIV-1 BF recombinants and their evolution over time through in-depth phylogenetic analysis and multiple recombination detection methods involving 337 HIV-1 nucleotide sequences (25 near full-length (NFL) and 312 partial pol gene) obtained from Argentinean MSM. The recombination profiles were studied using multiple in silico tools to characterize the genetic mosaicism, and phylogenetic approaches to infer their relationships. The evolutionary history of BF recombinants and subtype B sequences was reconstructed by a Bayesian coalescent-based method. By phylogenetic inference, 81/312 pol sequences clustered within BF clade. Of them, 46 sequences showed a genetic mosaic with CRF12_BF-like patterns, including plausible second-generation recombinants. Other CRFs_BF like (CRF17, 28, 29, 39, 42, 44, 47) and probable URFs_BF were less frequently found. Phylogenetic and recombination analyses on NFL sequences allowed a meticulous definition of new BF mosaics of genomic patterns. The Bayesian analyses pointed out quite consistent onset dates for the CRFs_BF clade based on B and F gene datasets (~1986 and ~1991 respectively). These results indicate that the CRFs_BF variants have been circulating among Argentinean MSM for about 30 years. This study reveals, through growing evidence showing the importance of MSM in the dynamics of the HIV-1 epidemic in Argentina, the coexistence of CRF12_BF-like and high diversity of strains exhibiting several BF mosaic patterns, including non-reported URFs that may reflect active clusters as potential intervention targets to hinder HIV-1 transmission.

High acceptability of rapid HIV self-testing among a diverse sample of MSM from Buenos Aires, Argentina.

INTRODUCTION: The objective of this study was to explore the acceptability of rapid HIV self-testing (RHST) among men who have sex with men (MSM). METHODS: During 2006-2009, a sample of 500 MSM was recruited through Respondent Driven Sampling for an HIV prevalence/incidence study. Attitude toward RHST was explored among HIV negative MSM. Data were weighted prior to analyses. RESULTS: Participants reported they were likely to buy RHST (74%), test themselves more frequently than they currently do (77%), and that the procedure would simplify testing (70%). Furthermore, 71% reported they would probably use it alone, 66% would use it with a steady partner, and 56% with a friend/partner. While a majority acknowledged that RHST use would deprive them of receiving counseling (61%), 74% declared they would go for help if they tested positive; 57% would use an RHST in order to avoid condoms. Probability of use surpassed 70% among gay and non-gay identified MSM as well as those with and without a previous HIV test. Those likely to buy RHST were older (p = 0.025) and more likely to identify as gay (p = 0.036). A total of 17% said they would think about killing themselves and 9% would attempt suicide if they tested positive. These MSM were more likely to be younger (p<0.001), with lower mood level (p<0.001) and greater feelings of loneliness (p = 0.026). CONCLUSIONS: The high acceptability of RHST found among MSM should encourage the authorities to consider the possibility of offering it for self-testing, as it can improve early diagnosis and prevention of future transmissions. However, further research is needed to understand how to best disseminate RHST among MSM who wish to use it and to offer support and linkage to care for those who test HIV-positive.

High Frequency of Illegal Drug Use Influences Condom Use Among Female Transgender Sex Workers in Argentina: Impact on HIV and Syphilis Infections.

The high prevalence of HIV and syphilis found among female transgender sex workers (FTSWs) in Argentina calls for the study of factors leading to negative health consequences. Given the particular characteristics observed in this population (high marginalization, school dropout, and low adherence to healthcare services), we explored the association of several socio-demographic characteristics with syphilis and HIV infections, and the determinants of condom use. This study revealed that FTSWs from Argentina were exposed to several risk factors decreasing thus their ability to negotiate condom use and leading to increased risk for transmission of HIV and other sexually transmitted infections (STIs). Strategies to reduce HIV and syphilis in this population should consider interventions aimed at decreasing violence and substance use which appear to be the most important determinants. Results of this study will contribute to the global information among FTSWs.

Reseña del estudio "LINKS": Factores asociados a la infección por VIH en hombres que tienen sexo con hombres de Buenos Aires, Argentina / Review of the "LINKS" study: Factors associated with HIV infection in men who have sex with men in Buenos Aires, Argentina

Este artículo resume resultados publicados del proyecto LINKS. Un to-tal de 500 hombres que tienen sexo con hombres se incluyeron en un estudio de factores asociados a la infección por VIH, utilizando la meto-dología de Muestreo Dirigido por los Participantes (Respondent Driven Sampling, RDS, en inglés). El 24,5 % se identificó como homosexual, 36,2 % como bisexual, 21,9 % como heterosexual y 17,4 % como "otro". El 33 % de los participantes reportó haber tenido relaciones sexuales con hombres, mujeres y mujeres trans durante los 2 meses previos. La prevalencia de VIH, hepatitis B y sífilis fue de 17,3 %, 22,9 % y 20,5 %, respectivamente. Los participantes que sólo reportaron parejas sexua-les masculinas tuvieron prevalencias significativamente mayores. Más de dos tercios reportaron coito anal o vaginal sin protección durante los últimos dos meses. El 52 % nunca se había realizado el diagnóstico de VIH. El 25 % informó consumo ex-cesivo de alcohol y 34 % poli-consumo de drogas du-rante los dos meses previos. El 18 % de participantes reportó una experiencia sexual antes de los 13 años con una pareja al menos cuatro años mayor de edad. La aceptabilidad de los microbicidas y de la prueba casera del VIH fue alta

[Summary of the LINKS Study: Factors associated with HIV infection among men who have sex with men in Buenos Aires, Argentina]. / Reseña del estudio "LINKS": Factores asociados a la infección por VIH en hombres que tienen sexo con hombres de Buenos Aires, Argentina.

This article summarizes published findings from Project LINKS. A total of 500 men who have sex with men were recruited through Respondent Driven Sampling into this study on factors associated with HIV infection. Among participants, 24.5 % identified as gay, 36.2 % as bisexual, 21.9 % as heterosexual, and 17.4 % as "other"; 33 % reported having sex with men, women, and transgender women during the prior two months. Prevalence of HIV, Hepatitis B, and syphilis was 17.3 %, 22.9 %, and 20.5 %, respectively; rates were significantly higher among participants who only had male sex partners. Over two-thirds of participants reported unprotected anal or vaginal intercourse during the prior two months, and 52 %had never been tested for HIV. Twenty-five percent reported heavy drinking, and 34 % reported poly-drug use during the past two months. Eighteen percent of participants reported a sexual experience prior to the age of thirteen with a partner who was at least four years older. Acceptability of microbicides and HIV home testing was high.

Childhood sexual experiences with an older partner among men who have sex with men in Buenos Aires, Argentina.

This study sought to describe childhood sexual experiences with older partners (CSEOP) among men who have sex with men (MSM) in Buenos Aires, Argentina. MSM were recruited through respondent driven sampling. They responded to a computer administered self-interview with questions on CSEOP, operationalized as manual, oral, genital, or anal contact prior to age 13 with a partner at least 4 years older. Of the 500 respondents, only 25% identified as gay. Eighteen percent of the respondents reported CSEOP, the majority of whom did not feel they were hurt by the experience and did not consider it to be childhood sexual abuse (CSA). Over two-thirds of MSM who reported CSEOP said that their older partner was a female. Only 4% of those with a female partner felt their experience was CSA compared to 44% of those who had a male partner. Among all men reporting CSEOP, those who felt sexually abused were more likely to have been physically forced or threatened, physically hurt, and emotionally hurt than those who did not feel sexually abused. Having CSEOP, being hurt by the experiences, and perceiving the experiences as sexual abuse were not associated with current HIV sexual risk or substance use behavior. In this sample of MSM in Argentina, a substantial minority reported CSEOP. Those who felt they had been sexually abused were much more likely to have had an older male partner than an older female partner, and were more likely to report having been physically forced and threatened by their older partner.

Low frequency of male circumcision and unwillingness to be circumcised among MSM in Buenos Aires, Argentina: association with sexually transmitted infections.

OBJECTIVE: The aims of this study were to investigate the frequency of male circumcision among men who have sex with men (MSM) in Buenos Aires, Argentina; the association between circumcision and sexually transmitted infections (STIs); and, among those uncircumcised, the willingness to be circumcised. METHODS: A cross-sectional study was conducted among 500 MSM recruited through the respondent-driven sampling (RDS) technique. Participants underwent a consent process, responded to a Web-based survey that included questions on demographic information, sexual behaviour, and circumcision and provided biological samples. HIV, hepatitis B virus (HBV), hepatitis C virus (CV), Treponema pallidum, and human papiloma virus (HPV) diagnoses were performed using standard methodologies. For all analyses, data were weighted based on participants' network size. RESULTS: Only 64 (13%) of the 500 MSM in our study reported being circumcised. Among uncircumcised men (n=418), 302 (70.4%) said that they would not be willing to get circumcised even if the procedure could reduce the risk of HIV infection. When considering all participants, circumcision status was not significantly associated with HIV, HBV, HCV, T. pallidum or HPV infections. However, when we restricted the sample to men who do not practice receptive anal intercourse (RAI) and compared circumcised to uncircumcised men, the former (N=33) had no cases of HIV infection, while 34 of 231 (14.8%) uncircumcised men were HIV positive (p=0.020). Regarding HPV, uncircumcised men had a significantly larger number of different HPV types compared with circumcised men (mean 1.83 vs. 1.09, p<0.001) and a higher frequency of high-risk-HPV genotypes (47.6% vs. 12.5%, p=0.012). CONCLUSIONS: Consistent with international evidence, male circumcision appears to have a partial protective effect among MSM. The efficacy of circumcision in reducing risk of HIV infection among MSM appears to be correlated with sexual practices. Given the lack of motivation among MSM with regard to circumcision, proper awareness on the risks and benefits of circumcision needs to be created, if circumcision has to be introduced as a prevention strategy.

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.

HIV knowledge and beliefs among men who have sex with men (MSM) in Buenos Aires, Argentina.

Five hundred men who have sex with men (MSM), recruited through respondent driven sampling in Buenos Aires, Argentina, were interviewed in order to assess knowledge and beliefs about HIV infection. The mean proportion of HIV correct knowledge answers was 62 %; however participants whose sexual partners in the prior year included women (MSM&W) had lower frequencies of correct answers than participants with no women partners. Men with previous HIV testing experience and those who were HIV positive had higher HIV knowledge. In relation to HIV beliefs, less than half of participants responded correctly to each of the scenarios presented. Accurate answers for all items were more likely among those who only have sex with men. Men have basic HIV knowledge but also many misconceptions about transmission and prevention. Furthermore, MSM&W have less information than those who are exclusively MSM, probably related to the fact that information campaigns specifically targeted gay identified men.

High prevalence of substance use among men who have sex with men in Buenos Aires, Argentina: implications for HIV risk behavior.

Five hundred gay and other men who have sex with men (G&MSM) from Buenos Aires, Argentina completed an assessment regarding substance use and sexual behavior. During the past 2 months, 78 % of participants consumed alcohol and 61 % drugs. Over 20 % of participants reporting alcohol, marijuana, cocaine sulfate, or tranquilizer use, did so daily. Heavy alcohol use was more likely among participants with greater mood reactivity (AOR = 1.64) and less likely among those who identified as gay (AOR = 0.38). Weekly drug use was less likely among older (AOR = 0.98), and gay-identified participants (AOR = 0.50), but more likely among participants with greater mood reactivity (AOR = 1.49). Drug use was correlated with unprotected anal and vaginal intercourse with men, women, and transvestites among non-gay identified participants (r = 0.22). Findings highlight the need to reduce substance use and sexual risk behavior in this population.

Epidemiología de HIV y otras ITS en población de trans (hombre a mujer) y hombres trabajadores sexuales de Argentina / HIV and STIs epidemiology among trans (male to female) and male sex workers in Argentina

El objetivo del estudio fue aportar conocimiento sobre infecciones de transmisión sexual (ITS) en poblaciones de alta vulnerabilidad sobre las cuales la información era casi inexistente como son trans (travestis, transexuales o transgénero, hombre a mujer) (TTS) y hombres (HTS) trabajadores sexuales. Métodos: Se realizó un estudio de corte transversal con un muestreo de conveniencia de TTS y HTS mayores de 18 años de edad en siete ciudades argentinas (2006-2009). Resultados: La incidencia de HIV fue mayor en TTS que en HTS (10,7 y 2,3 por 100 personas-año, respectivamente). Las TTS (N=273) mostraron una prevalencia significativamente mayor que los HTS (N=114) de HIV (34,1 vs. 11,4%), HBV (40,2 vs 22,0%) y Treponema pallidum (50,4 vs. 20,4%). Las prevalencias de infección por HCV y HTLV-1/2 no fueron significativamente diferentes (HCV: 4,5 y 6,1%; HTLV-1/2: 1,8 y 1,0%, respecivamente). En un grupo de TTS fue posible determinar la prevalencia de HPV y Chlamydia trachomatis y sus variantes. Las TTS resultaron positivas para HPV en 111/114 (97,4%) casos y para C. trachomatis en 5/113 (4,4%) casos. Los genotipos más frecuentes de HPV fueron el 16, 42, 81 y 58 (el primero y el último de alto riesgo oncogénico). Conclusión: La alta prevalencia de ITS y la alta incidencia de HIV demuestran la gran vulnerabilidad de estas poblaciones e indican la urgente necesidad de implementar estrategias preventivas y de facilitar el acceso a programas de salud para las mismas

Objective: The aim of this study was to generate knowledge on sexually trnsmitted infections (STIs) among highly vulnerable groups on whom information was scarce, namely male-to-female trans sex workers (TSW) and male sex workers (MSW). Methods: This was a cross-sectional study with convenience sampling of TSW and MSW older than 18 years of age in seven Argentinean cities (2006-2009). results: HIV incidence among TSW was higher than MSW (10.7 and 2.3 pero 100 person-years respectively). TSW (N=273) showed a isgnificantly higher prevalence of HIV (34.1 vs. 11.4%), HBV (40.2 vs 22.0%) and Treponema pallidum (50.4 vs 20.4%) than MSW (N=114). HCV and HTLV-1/2 prevalence was not significantly different among TSW and MSW (HCV: 4.5 and 6.1%; HTLV-1/2: 1.8 and 1.0% respectively). Besides, it was possible to determine HPV and Chlamydia trachomatis prevalence and variants in one group of TSW. TSW tested positive for HPV in 111/114 cases (97.4%) and form C. trachomatis in 5/113 cases (4.4%). The most frequent HPV genotypes were 16, 42, 81 y 58 (the first and the last corresponding to oncogenic types). Conclusin: The high prevalence of STIs and the high incidence of HIV demonstrate the great vulnerability of these high risk populations and stress the urgent need form preventive strategies on intervention and facilitation of access to healthcare programs

Epidemiología de HIV y otras ITS en población de trans (hombre a mujer) y hombres trabajadores sexuales de Argentina / HIV and STIs epidemiology among trans (male to female) and male sex workers in Argentina

El objetivo del estudio fue aportar conocimiento sobre infecciones de transmisión sexual (ITS) en poblaciones de alta vulnerabilidad sobre las cuales la información era casi inexistente como son trans (travestis, transexuales o transgénero, hombre a mujer) (TTS) y hombres (HTS) trabajadores sexuales. Métodos: Se realizó un estudio de corte transversal con un muestreo de conveniencia de TTS y HTS mayores de 18 años de edad en siete ciudades argentinas (2006-2009). Resultados: La incidencia de HIV fue mayor en TTS que en HTS (10,7 y 2,3 por 100 personas-año, respectivamente). Las TTS (N=273) mostraron una prevalencia significativamente mayor que los HTS (N=114) de HIV (34,1 vs. 11,4%), HBV (40,2 vs 22,0%) y Treponema pallidum (50,4 vs. 20,4%). Las prevalencias de infección por HCV y HTLV-1/2 no fueron significativamente diferentes (HCV: 4,5 y 6,1%; HTLV-1/2: 1,8 y 1,0%, respecivamente). En un grupo de TTS fue posible determinar la prevalencia de HPV y Chlamydia trachomatis y sus variantes. Las TTS resultaron positivas para HPV en 111/114 (97,4%) casos y para C. trachomatis en 5/113 (4,4%) casos. Los genotipos más frecuentes de HPV fueron el 16, 42, 81 y 58 (el primero y el último de alto riesgo oncogénico). Conclusión: La alta prevalencia de ITS y la alta incidencia de HIV demuestran la gran vulnerabilidad de estas poblaciones e indican la urgente necesidad de implementar estrategias preventivas y de facilitar el acceso a programas de salud para las mismas (AU)

Objective: The aim of this study was to generate knowledge on sexually trnsmitted infections (STIs) among highly vulnerable groups on whom information was scarce, namely male-to-female trans sex workers (TSW) and male sex workers (MSW). Methods: This was a cross-sectional study with convenience sampling of TSW and MSW older than 18 years of age in seven Argentinean cities (2006-2009). results: HIV incidence among TSW was higher than MSW (10.7 and 2.3 pero 100 person-years respectively). TSW (N=273) showed a isgnificantly higher prevalence of HIV (34.1 vs. 11.4%), HBV (40.2 vs 22.0%) and Treponema pallidum (50.4 vs 20.4%) than MSW (N=114). HCV and HTLV-1/2 prevalence was not significantly different among TSW and MSW (HCV: 4.5 and 6.1%; HTLV-1/2: 1.8 and 1.0% respectively). Besides, it was possible to determine HPV and Chlamydia trachomatis prevalence and variants in one group of TSW. TSW tested positive for HPV in 111/114 cases (97.4%) and form C. trachomatis in 5/113 cases (4.4%). The most frequent HPV genotypes were 16, 42, 81 y 58 (the first and the last corresponding to oncogenic types). Conclusin: The high prevalence of STIs and the high incidence of HIV demonstrate the great vulnerability of these high risk populations and stress the urgent need form preventive strategies on intervention and facilitation of access to healthcare programs (AU)

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.

Significantly longer envelope V2 loops are characteristic of heterosexually transmitted subtype B HIV-1 in Trinidad.

BACKGROUND: In Trinidad and the wider Caribbean, subtype B Human Immunodeficiency Virus-type 1 (HIV-1B) overwhelmingly accounts for HIV infection among heterosexuals; this contrasts with the association of HIV-1B with homosexual transmission and injecting drug use globally. The HIV envelope contains genetic determinants of cell tropism and evasion from immune attack. In this study we investigate the genetic properties of the env V1-C4 of HIV-1B soon after transmission to Trinidadian heterosexuals. This will reveal distinctive genetic features of the strains that cause the HIV-1B epidemic in Trinidad and generate insights to better understand their properties. METHODOLOGY/PRINCIPAL FINDINGS: Quasispecies sampling was performed on the env V1-C4 of HIV-1B strains soon after transmission to heterosexual Trinidadians in a cohort of seroconverters. Phylogenetic relationships were determined for these quasispecies and the length and number of asparagine (N) linked glycosylation sites (NLGS) in their variable loops compared to that for HIV-1B globally. Signature amino acids within the constant domains of the env V1-C4 were identified for heterosexually transmitted HIV-1B from Trinidad relative to HIV-1B globally. HIV-1B obtained from Trinidadian heterosexuals soon after seroconversion had significantly longer V2 loops with one more glycosylation site, shorter V3 loops and no significant difference in V1 or V4 when compared to HIV-1B obtained soon after seroconversion from infected individuals in the rest of the world. HIV-1B soon after seroconversion and during chronic infection of Trinidadians was not significantly different, suggesting that distinctly long V2 loops are characteristic of HIV-1B in Trinidad. A threonine deletion at position 319 (T319-) along with the substitutions R315K and S440R were found to be distinctly associated with HIV-1B from Trinidad compared to HIV-1B globally. CONCLUSIONS: This finding of distinctive genetic features that are characteristic of HIV-1B strains from Trinidad is consistent with the Trinidad epidemic being established by a founder strain or closely related founder strains of HIV-1B.

Presentación del estudio "Links" de hombres que tienes sexo con hombres en Buenos Aires, Argentina.

Estudios previos en Buenos Aires reportaron altas prevalencias de HIV entre HSH, con valores que oscilan entre 9 y 14% durante casi 10 años de continuo testeo. El objetivo principal de este estudio fue la evaluación de factores relacionados al comportamiento de alto riesgo para transmisión del HIV entre HSH entre los que se incluyen el conocimiento y factores emocionales, socioculturales y ambientales. Por otro lado se realizó la estimación de prevalencia e incidencia de HIV utilizando RDS (Respondent Driven Sampling), así como la presencia de otras infecciones de transmisión sexual. Por último se evaluaron los hábitos de testeo para HIV indagando que factores facilitan o impiden su realización. El estudio constó de dos fases, en primer lugar una fase cualitativa y posteriormente una fase cuantitativa con una duración total de 4 años y medio. Durante la fase cualitativa se realizaron 44 entrevistas individuales en profundidad, 8 grupos focales y 10 observaciones etnográficas (hoteles, baños públicos ("teteras"), cines pornográficos, fiestas privadas, dark rooms y discotecas). Durante la fase cuantitativa del estudio se realizó el reclutamiento de 500 participantes que provinieron de la Ciudad Autónoma de Buenos Aires, así como del Gran Buenos Aires. El reclutamiento se comenzó con 16 participantes llamados semillas. Se realizó el diagnóstico de infección por HIV, hepatitis B y C (HBV y HCV), Treponema pallidum, Virus Papiloma Humano (HPV) y Chlamidias. La colaboración establecida entre los grupos de trabajo enfocados en áreas diversas posibilitó el abordaje conjunto de nuevas estrategias de investigación antes no exploradas en nuestro país. Los resultados más relevantes de esta investigación serán progresivamente publicados en sucesivos números de Actualizaciones en SIDA.

Aceptabilidad del diagnóstico rápido casero para HIV entre hombres gay y otros hombres que tienen sexo con hombres (G&HSH) de la Ciudad de Buenos Aires.

El uso del diagnóstico rápido para HIV en Argentina, así como otros países de Latinoamérica, ha sido limitado hasta el momento. Este trabajo reporta los resultados provenientes de un estudio cualitativo realizado entre hombres gays y otros hombres que tienen sexo con hombres (G&HSH) de la Ciudad de Buenos Aires, Argentina. El objetivo principal del mismo fue conocer las ventajas y desventajas que los hombres G&HSH perciben en relación al diagnóstico rápido casero para HIV. Se realizaron ocho grupos focales con 73 participantes en los cuales se discutió acerca de las ventajas y desventajas del uso de los diagnósticos rápidos. Las respuestas fueron codificadas utilizando un programa para análisis de datos cualitativos (NVivo) y analizadas temáticamente. Los participantes describieron numerosas ventajas sobre el uso del diagnóstico rápido casero, aunque algunos reportaron importantes preocupaciones dentro de las cuales se destaca la posibilidad de impulsos suicidas si alguien recibe un resultado positivo estando solo. En términos generales se observó una gran aceptabilidad para el uso del diagnóstico rápido si el mismo es realizado por personal de salud en lugares acondicionados para este fin.

HIV/STI co-infections, syphilis incidence, and hepatitis B vaccination: the Buenos Aires cohort of men who have sex with men.

In a previous cohort study among 327 men who have sex with men (MSM) in Buenos Aires, an HIV incidence rate of 3.9 per 100 persons-year was reported. Using data from this study, we determined: (a) HIV/STI co-infections; (b) clinical manifestations of incident HIV infections; (c) syphilis incidence and its associated risk factors; and (d) adherence and immune response to hepatitis B virus (HBV) vaccine. During the cohort study, 12 incident HIV infections were found. Within this group, HIV infection alone was most frequent (42%), followed by co-infection of HIV/HBV (33%), and triple co-infection of HIV/HBV/syphilis (25%). The most frequent clinical manifestations among incident HIV cases were: pharyngitis, fever, lymphadenopathy, asthenia, and myalgia. Seven new syphilis infections were detected yielding an incidence rate of 2.4 (95% CI=1.07 - 4.73) per 100 persons-year. Sex work was the only significant risk factor associated with syphilis seroconversion (hazard rate=10.93, p-value=0.033). Only 7% of cohort participants reported having received HBV vaccine. Ninety-percent of the 204 cohort members who agreed to be vaccinated completed the HBV vaccination schedule with an immune response rate of 85%. Our findings suggest the need to increase the access to serologic testing for STI and HBV immunization, as well as the developing of effective HIV/STI behavioral and educational prevention programs among MSM in Buenos Aires.