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ABSTRACT |
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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30 years, adjusted odds ratio [AOR] = 2.6 to 4.9), 10 years in sex work (AOR = 2.2), use of illegal drugs (AOR = 2.1), and a prior history of an STI (AOR = 3.0). HBV and syphilis was the most common co-infection in 44 (7.5%) subjects. FSWs in Argentina are exposed to HIV and other STIs due to high-risk sexual and illegal drug use behavior. Renewed efforts are necessary to intervene effectively in this high-risk population. |
INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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A history of multiple sex partners, irregular condom use by clients, and co-infection with other STIs constitute potential risk factors associated for HIV infection among FSWs.4,5 Elevated HIV prevalences (62–80%) have been reported in some countries of Africa, such as Kenya,6 Ivory Coast,7 and Ethiopia.8 By contrast, the prevalence of HIV among FSWs in Latin America appears to vary greatly, as low as 0–1% in South America (with the exception of Guyana and Brazil) and as high as 5–10% in certain countries of Central America, such as Guatemala and Honduras.9–11
Argentina, after Brazil, is the country with the highest number of acquired immunodeficiency syndrome (AIDS) cases reported in South America.10 Of the approximately 27,000 AIDS cases reported in Argentina between 1982 and 2004, 30% of these were accounted through heterosexual transmission. However, during 2003, 47% of notified AIDS cases were due to heterosexual transmission. In this country, spillover of HIV transmission takes place from the high-risk groups of injection drug users into the heterosexually active general population.12
Hepatitis C virus (HCV), hepatitis B virus (HBV), human T-cell lymphotropic virus types I/II (HTLV-I/II), and syphilis infections are commonly reported in the same high-risk groups where HIV infection is present due to shared modes of transmission.13 A recent cross-sectional study conducted among 174 heterosexually active, HIV-infected men and women in Buenos Aires in 1999 reported prevalences of 30% for HCV, 12.2% for HBV, and 3.8% for HTLV-I/II.14 In addition, an association between HTLV-I//II and HIV infection has been also observed among 237 FSWs in Buenos Aires in 1996.15 Thus, it is likely, although unproven, that viral pathogens such as HBV, HCV, HTLV-I/II, and Treponema pallidum (syphilis) infections may influence the HIV epidemic among FSWs in Argentina.
To better guide future HIV and STI-specific prevention strategies, an epidemiologic cross-sectional study was conducted among FSWs to estimate the seroprevalence of HIV and other STIs, as well as to identify potential risk factors for exposure to these STIs in Argentina.
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MATERIALS AND METHODS |
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. FSW participants (following the UNAIDS definition,16 women who receive money or goods in exchange for sexual services, either regularly or occasionally, and who may or may not consciously define those activities as income generating) 18 years of age were eligible for this study. In Buenos Aires, street-based FSWs were contacted and referred to the offices of an NGO. In the other five cities, FSWs were contacted in the street, bath-houses, nightclubs, and brothels. Additionally, in each city, FSWs were also contacted by other FSWs.
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Serological test results were linked to the questionnaire by a unique numeric code that preserved confidentiality and anonymity of the participants. All participants received free STI counseling and HIV testing and were scheduled to return in a period of 2 weeks to receive their serological test results and post-test counseling. All HIV-positive participants were referred to an infectious diseases clinic for further clinical assessment and provision of antiretroviral treatment. This research was reviewed by institutional review boards and scientific ethical committees at the University of Buenos Aires and at the U.S. Naval Medical Research Center (NMRC) in the United States and was conducted in compliance with all federal regulations governing the protection of human subjects.
Blood sample collection and diagnosis of STI. A sample of anticoagulated blood was collected in sterile fashion for determination of STI. All sera samples were sent to the Centro Nacional para el SIDA laboratory for analysis. HIV diagnosis was performed by means of enzyme-linked immunosorbent assay (ELISA) and by agglutination techniques (GENSCREEN Plus HIV AgAb, BioRad; Marnes la Coquette, France; Serodia HIV, FUJIREBIO, Tokyo, Japan). Samples found to be reactive were confirmed by Western blot (WB) assay (Novapath HIV-I, Immunoblot, BioRad, CA). The presence of antibodies to HTLV-I/II was initially determined by particle agglutination technique (Serodia-HTLV-I, FUJIREBIO, Tokyo, Japan) and by ELISA (Platelia HTLV-1 New, BioRad, Marnes la Coquette, France). Those samples that resulted repeatedly reactive for HTLV-I/II were subsequently confirmed by WB (HTLV Blot 2.4, Genelabs Diagnostics, Science Park, Singapore). Markers of infection by HBV, such as surface antigen (HBsAg) and anti-core antibody (anti-HBc) were determined by ELISA (HBsAg ELISA, Wiener Laboratories S.A.I.C., Rosario, Argentina; anti-HBc ELISA, Wiener Laboratories S.A.I.C., Rosario, Argentina). HBV infection was considered to be positive if at least one of the markers of HBV infection was present. To determine past infection with HCV, anti-HCV testing was performed by ELISA (anti-HCV ELISA, Wiener Laboratories S.A.I.C., Rosario, Argentina). Past infection with syphilis was determined by a recombinant ELISA (Sífilis, ELISA re-combinante; Wiener Laboratories S.A.I.C., Rosario, Argentina) at the Laboratorio de Hemoterapia, Hospital de Clínicas José de San Martín, Buenos Aires, Argentina.
Statistical analysis. Chi-square and Fisher’s exact test were used to compare differences in categorical variables. ANOVA (analysis of variance) test was used to compare differences among means of continuous variables. Ninety-five percent confidence intervals (95% CI) for seroprevalence were estimated by using exact binomial formula. The magnitude of associations of potential risk factors in univariate analyses was expressed as odds ratio (OR). Multiple logistic regression analysis was applied to determine adjusted odds ratio by age and city (AOR). All risk factors that were found to be statistically significant in univariate analyses or with a P < 0.05 were entered into a forward, stepwise selection multivariate logistic regression to identify independent risk factors associated with HIV and STI. All reported P values were two-sided; P values < 0.05 were considered to be statistically significant. All statistical analyses were carried out using Epi-Info version 6.4 and STATISTICA (StatSoft, version 5, 1997 Edition).
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RESULTS |
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shows the sociodemographic and behavioral characteristics of study participants. Participants’ age ranged from 18 to 73 years (mean = 33.8 years), and around three-fourths (456) of study participants were Argentinian. The foreigner FSWs were mostly from Paraguay (65), Dominican Republic (54), Brazil (17), Peru (12), and Uruguay (11). Only one in five FSWs reported having a second job (such as housewife or street saleswoman). Thirty-six percent (226) of subjects reported a high school education level.
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Table 2 shows the characteristics of sexual work among FSWs. A great variability was observed in terms of time (years) in sex work (mean = 7.9, range = 1 to 47), and in the number of sexual contacts a week (mean = 14.5, range = 1 to 140). Approximately 90% of the study participants reported less than 30 clients a week. A higher number of sexual contacts a week was especially noted among FSWs from the city of Salta (mean = 28). The most frequent sexual practice was vaginal intercourse (82.1%), followed by oral sex (64.8%) and anal intercourse (8.5%). Irregular condom use with clients was reported by 113 (18.1%) subjects. Eighty-seven percent (516 of 593) FSWs responded that clients preferred not to use condom during the sexual act. Of these, only 9.3% (48) accepted their client’s request. In addition, a pattern of irregular condom use was also found to be significantly higher with steady partners (87.5%) than with clients (18.1%, P < 0.05).
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). Forty-eight (17.6%) of the 273 FSW participants who were tested positive for syphilis infection were already aware of their serological status.
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Foreign nationality was found to be a protector factor for HBV infection (OR = 0.6, 95% CI = 0.4 to 0.9). Past HBV infection was more prevalent but not statistically significant associated among those FSWs without formal education level (26.9%), among those street-based FSWs (16.3%), and among those who reported a prior history of an STI (17.2%). By contrast, HCV infection was found to be statistically associated among those Argentinian FSWs (OR = 4.7, 95% CI = 1.1 to 29.3) compared to other FSWs, and among those who were 40–49 years of age (OR = 3.0, 95% CI = 1.1 to 8.3) compared to participants less than 30 years of age. A higher risk for HTLV-I infection was found among Argentinian FSWs than among those FSWs from other countries (OR = 28.3, 95% CI = 4.9 to 154.1).
Several potential risk factors were found to be associated with syphilis infection in univariate logistics regression analysis, including 30 years of age or older, Argentinian nationality, other occupation than sex work, more than 10 years in sex work, earning less than 10 Argentinian pesos (equivalent to 3–4 USD) per sexual contact, use of illegal drugs, not having a steady partner, as well as for those who reported a prior history of an STI and alcohol consumption (more than once a week) (Table 4). In multiple logistic regression analysis after adjusting for age and city, study participants who were 30 years of age or older, or among those who reported more than 10 years in sex work, use of illegal drugs and a prior history of an STI remained to be statistically significant associated with syphilis infection. In addition, four independent risk factors were found to be associated for syphilis infection by the multivariate logistic regression analysis: these were time exposure to sex work (OR = 8.2 per year, 95% CI = 2.3 to 29.1), age (OR = 6.9 per year, 95% CI = 1.9 to 24.5), other occupation than sex work (OR = 1.8, 95% CI = 1.1 to 2.8), and use of illegal drugs (OR = 1.7, 95% CI = 1.1 to 2.6).
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. The most common co-infection found was HBV and syphilis, which was detected in 44 (7.5%) of study participants. HTLV and HBV (OR = 12.0, 95% CI = 1.9 to 96.1) as well as syphilis and HBV (OR = 2.1, 95% CI = 1.3 to 3.4) were found to be significantly associated with each other.
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DISCUSSION |
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This cross-sectional study provides an important opportunity to assess the status of the HIV infection among FSWs in different cities of Argentina and represents the first STI seroprevalence study conducted among FSWs in this country. Previous epidemiologic studies conducted among FSWs in Argentina have been based on samples from individuals who sought assistance (represented biased sampling), therefore the prevalences of HIV reported were probably overestimated, ranging from 1.4% to 2.3% in the city of Rosario18 and from 3.4% to 11.6% in the capital city of Buenos Aires.19–21 A previous cross-sectional study conducted among FSWs in Buenos Aires in 199615 reported a prevalence of 6.3% for HIV and 13.2% for syphilis. However, this study was conducted among those FSWs who worked exclusively in brothels, and not especially among mostly street-based workers.
Our study suggests that there may exist subpopulations of female sex workers that are likely to be more vulnerable to STIs than others. For example, FSWs from the northern city of Salta reported high STI prevalences, which is most probably associated with their poor working conditions in the region (as reflected by the lowest fee per sexual contact) and increases in risk behavior such as concomitant drug use, alcohol use, and risky (unprotected) sexual contact with clients. A higher prevalence of HTLV-I infection was also found in this city, a finding that correlates with the known higher level endemicity of HTLV-I among populations in the province of Jujuy (a neighbor province of Salta).22
The high prevalence of syphilis found in this study (45.7%) contrasts with the results obtained in a similar study conducted among 212 FSWs who attended STI clinics/centers in Venezuela23 in 2003 (2.4%). The low prevalence of syphilis reported may be attributed to the routine control of syphilis performed in Venezuela, where FSWs who are diagnosed with syphilis have their work licenses revoked until treatment is completed. In addition, a lower seroprevalence for HCV (0.5%), HBsAg (3.8%), anti-HBc (13.8%), and HIV (0%) infection were also noted.
Vaccination for HBV has been available since 198224; however, in Argentina it is not obligatory. Recently, it has become compulsory for children and preadolescents, but the adult population does not have access to this vaccine unless they buy it. Due to the high transmission rate of HBV and the unvaccinated adult population in Argentina, is advisable to give the vaccine to the FSW population in whom a high prevalence has been reported as well as to recommend HBV vaccination to the adult heterosexual population.
The irregular condom use noted in this study especially among those FSWs with their steady partners suggests that female sex workers only consider being at high risk with clients or nonsteady partners. Future studies are necessary to better understand this behavior.
The high STI prevalences found among FSWs in Argentina suggest that it is essential that prevention programs focus not only on the high risks associated with commercial sex work but also the risks with other sexual partners (casual or steady). However, such programs need to be locally adjusted to the prevalent distribution of behavioral and societal factors associated with transmission of STIs among female sex workers and should not permit the stigmatization of and discrimination against this high-risk group.
Received October 4, 2004. Accepted for publication March 10, 2005.
Acknowledgments: The authors want to thank Wiener Laboratory Argentina for the supply of the reagents used for HBV, HCV, and syphilis diagnosis. In addition, we would like to thank Dr. Jean K. Carr at the U.S. Military HIV Research Program, Rockville, Maryland, for her advice and critical review of this manuscript and assistance with its preparation, and Sebastian A. for his technical support.
Financial support: This work was supported by the U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Rockville, Maryland, and by the U.S. Naval Medical Research Command, Silver Spring, Maryland, Work Unit No. 62787 A 873 H B0002.
Disclaimer: The opinions and assertions made by the authors do not necessarily reflect the official position or opinion of the Argentinian Ministry of Health, the U.S. Department of Defense health officials, and the Henry M. Jackson Foundation Advancement of Military Medicine, Inc.
* Address correspondence to María M. Avila, Centro Nacional de Referencia para el SIDA, Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Piso 11, C1121ABG, Buesnos Aires, Argentina. E-mail: mavila{at}fmed.uba.ar 
Authors’ addresses: María A. Pando, Carolina Berini, Mariel Bibini, Mirna Biglione, Mercedes Weissenbacher, and María M. Avila, Centro Nacional de Referencia para el SIDA, Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Piso 11, C1121ABG, Buenos Aires, Argentina, Telephone: 54-11-4508-3689/3671, Fax: 54-11-4508-3705, E-mail: mpando{at}fmed.uba.ar and mavila{at}fmed.uba.ar. Mauro Fernández, Laboratorio de Hemoterapia, Hospital de Clínicas "Jose de San Martín," Av. Córdoba 2351, Piso 3, Buenos Aires, Argentina, Telephone: 54-11-5950-8772, Fax: 54-11-5950-8769. Elena Reinaga, Organización AMMAR, Av. Independencia 766, CP 1099, Buenos Aires, Argentina, Telephone: 54-11-4307-3829. Sergio Maulen and Rubén Marone, NEXO Asociación Civil, Callao 339, Piso 5, CP 1022, Buenos Aires, Argentina, Telephone: 54-11-4375-0359. Silvia M. Montano, U.S. Naval Medical Research Center Detachment-Lima, Peru, Unit 3800, APO-AA 34031-3800, Telephone: 51-1-561-2733, Fax: 51-1-561-3042. Christian T. Bautista and José L. Sanchez, U.S. Military HIV Research Program, Walter Reed Army Institute of Research and the Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc, Rockville, Maryland, 1 Taft Court, Suite 250, Rockville, MD 20850, Telephone: 301-251-5000, Fax: 301-294-1898.
Reprint requests: María M. Avila, Ph.D., Centro Nacional de Referencia para el SIDA, Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Piso 11, C1121ABG, Buenos Aires, Argentina, Telephone: 54-11-4508-3689/3671, Fax: 54-11-4508-3705, E-mail: mavila{at}fmed.uba.ar.
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REFERENCES |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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