Prevalence of HIV, Herpes Simplex Virus-2, and Syphilis in male sex partners of pregnant women in Peru

The HIV epidemic in Peru remains concentrated in the core risk group of men who have sex with men (MSM) without extension into the general population [1‐3]. While research has been conducted on the social and biological mechanisms of disease transmission between MSM in the region, little attention has been paid to the issue of HIV infection and sexually transmitted infections (STIs) among heterosexuals in Peru [4‐6]. There is a need to further understand the epidemiology of HIV infection and STIs in Peru's general population in order to assess the potential for the spread of HIV/STIs within heterosexual networks.

Research has suggested that men in Peru generally have greater numbers of sex partners, and greater risk of potential STI exposures, than women [7, 8]. In studies of pregnant women in Lima, the sexual behavior of male partners was an important factor both in increasing the size of women's sexual networks, and in establishing women's indirect exposure to high-risk communities [9]. Among HIV-infected pregnant women, 26.7% of their HIV-positive male partners had engaged in sexual contact with other men and 46.7% had engaged in unprotected sex with a female sex worker. Yet, as in most other HIV surveillance studies in Peru, HIV prevalence in the study population was less than 1%, suggesting that the primary impact of male partners' risk behavior was on individual risk for infection without significantly impacting the population-level spread of disease.

Other analyses have investigated STIs and associated risk behaviors in subgroups of high-risk heterosexually active men in Peru, but few recent studies have examined the prevalence of disease or high-risk behavior within the general heterosexual population. In one study of male clients of female sex workers in Peru, chlamydial and gonococcal infections were uncommon, and only 4.2% of men surveyed reported engaging in unprotected intercourse with female sex workers [10]. In a separate study, men sexually active with both men and women had an elevated prevalence of HIV infection (11.1%), and high rates of unprotected vaginal and anal intercourse with both male and female partners [11]. In another analysis of heterosexual-identified men in low-income urban neighborhoods in Peru, 14.2% reported recent male sex partners, with the majority of those men engaging in unprotected sex with both male and female partners (84.2% and 57.0%, respectively) [12]. Additionally, a survey of heterosexual couples seeking treatment at STI clinics in Lima found frequent reports of risk behaviors such as unprotected sex with casual partners, male same-sex contact, and sex with female sex workers [6]. While these studies defined the risk behaviors of selected high-risk sub-groups, they did not estimate the size of these communities as a proportion of the overall population. In contrast, a 1991 survey of Peru's general population assessed HIV/STI prevalence and associated risk factors, and found high prevalences of reported risk behavior among male participants [8]. In a sample of 600 men and women, men reported ten times as many sex partners as women, and 36.6% of men reported contact with female sex workers. Only 8.9% of men reported always using condoms during intercourse with casual partners. However, only 7.7% of the men were found to have antibodies to HSV-2 and only one case of HIV infection was diagnosed in the study population. No recent studies have reported prevalence of HIV/STIs or associated risk factors for transmission among adults in the general population. We studied the prevalence of HIV infection and STIs among male partners of pregnant women in Peru to determine the prevalence of infections among heterosexually active males, and to assess their potential role in HIV/STI transmission to pregnant women and neonates in Peru.

Our results present an epidemiologic portrait of STI prevalence and risk behavior among male partners of pregnant women in coastal Peru. The rate of HSV-2 infection among men in our study indicates an important risk factor for HIV infection and potential congenital herpes transmission for HSV-2 naive female partners. In addition, a minority of men (less than 1.0%) had recent high-risk secondary sexual partnerships, indicating potential increase in risk for new HIV/STI acquisition and subsequent transmission to their partners and newborn children.

The 0.8% prevalence of HIV infection among our subjects was slightly higher than previous HIV surveillance estimates of 0.3–0.6% among pregnant women [3] and 0.4% among general population males [13]. However, it is not clear if the slightly elevated HIV prevalence reflects a significant increase in HIV infections in this population, or a statistical variance within in our sample. Additional studies are needed to address this issue.

The percentage of subjects with serologic evidence of HSV-2 infection (16.0%) suggests that genital ulcerative disease may be an important risk factor for HIV infection in this community. The link between genital herpes and HIV infection has been well established [14], with recently published studies specifically addressing the importance of HSV-2 seropositivity as a risk factor for HIV transmission in MSM populations in Peru [15, 16]. The presence of HSV-2 infection indicates a potential mechanism for future HIV transmission, despite inconclusive findings concerning prevalence of HIV infection in this population. In addition, the high risk for genital herpes transmission to HSV-2 negative pregnant women from their HSV-2 positive male partners speaks to the need for improved public health control of HSV-2, including educational campaigns to decrease transmission by limiting sexual contact and increasing use of antiviral treatment (e.g., acyclovir) during active outbreaks.

Our study has methodological limitations that may have influenced our findings. Interviews were conducted by the partner's obstetrician, which could have limited subjects' willingness to report recent sex partners outside of their current relationship, though reported lifetime contacts with MSM and female sex workers are consistent with other published studies [6, 8, 13]. A further complication is the fact that the majority of study participants (70%) were enrolled at hospital recruitment sites, with only 30% enrolled during home visits. This discrepancy in recruitment is probably due to the fact that participants recruited during home visits were obligated to attend an additional enrollment visit at the hospital study site in order to participate. As a result men less committed to the pregnancy of their partner, and possibly more likely to engage in sexual risk behavior outside of the relationship, were less likely to be included in the study. The refusal rates of participants recruited at the different sites were not recorded. Although men in our study are a sample of heterosexually active men engaging in unprotected intercourse, their status as the partner of a pregnant woman is also likely to have modified their risk behavior. Men outside of a committed relationship are likely to be at even higher risk for STIs and merit further study. Further, modifications in sexual practices that often occur as a result of a woman's pregnancy may also have substantially altered the risk behavior of one or both members of the partnership during the year preceding evaluation, significantly influencing the recent risk behaviors assessed in our study. As public health authorities consider the appropriateness of monitoring seroprevalence among pregnant women as a marker for disease prevalence in the general population, it may also be important to take steps to define an appropriate, corresponding male population for epidemiologic surveillance.

Male partners of pregnant women in Peru reported previous contact with groups at high risk for infection with HIV and other STIs, especially female sex workers, though recent contact with high-risk populations and diagnosis of active STIs was limited. While the prevalence of HIV and syphilis infection was relatively low, the high rate of HSV-2 seropositivity indicates a cofactor for HIV acquisition and transmission and a potential source of neonatal herpes infection that should be addressed. A small subset of these men reported recent, high-risk contact with core risk groups including female sex workers and MSM, and present a higher level of risk for HIV/STI transmission to their female partners and infant children on an individual level. Consistent public health interventions are needed in Peru to reduce risks of STI acquisition through reducing the number of sex partners and increasing condom use among heterosexuals, as well as increasing awareness, availability and uptake of STI screening. Surveillance of HIV infection and STIs among the male partners of pregnant women is important to develop a comprehensive framework for the analysis of sexual health in Latin America.