The association of herpes simplex virus type 2 (HSV-2), Haemophilus ducreyi, and syphilis with HIV infection in young men in northern Thailand

Vaginal microbiota and susceptibility to HIV

: Bacterial vaginosis, characterized by the replacement of the Lactobacillus-dominant microbiota with anaerobic bacteria and facultative Gram-negative rods, has been associated with adverse reproductive health outcomes including HIV acquisition. With the advent of newer molecular techniques, the vaginal microbiota can be investigated in more detail and the association with HIV examined more thoroughly. This review examines recent evidence suggesting that vaginal dysbiosis with increased microbial diversity, specific vaginal bacterial communities, and the presence and concentrations of some individual bacterial species, may increase HIV susceptibility. Potential mechanisms through which vaginal microbiota could impact HIV susceptibility are discussed. On the basis of the available data, this review finds that there is a modest, but growing, body of evidence linking vaginal microbiota to HIV susceptibility in women. The evidence could be strengthened through two main pathways. First, laboratory studies such as ex-vivo or animal experiments are needed to move from plausible mechanisms towards proven mechanisms that explain an effect of the vaginal microbiota on HIV susceptibility. Second, experimental evidence could directly test the hypothesis that sustaining optimal microbiota reduces HIV risk, though there are important obstacles to conducting such studies. Finally, this review examines strong evidence from a recent publication suggesting that deviations from an optimal vaginal microbiome, and particularly the presence of some bacterial communities with high relative abundance of Gardnerella vaginalis, reduces the efficacy of vaginal tenofovir-based microbicides.

An Update on the Global Epidemiology of Syphilis

PURPOSE OF REVIEW

Syphilis continues to cause morbidity and mortality worldwide. While syphilis infection is easily identifiable and treatable, rates of syphilis infection continue to increase among select populations in high-income countries and remain at endemic levels in low- and middle-income counties.

RECENT FINDINGS

World Health Organization recommended strategies have led to the dual elimination of mother-to-child transmission of syphilis and HIV in several countries, however outbreaks among select populations need to be adequately addressed.

SUMMARY

Continued vigilance and investment is needed to address syphilis worldwide. The epidemiology of syphilis differs in high-income and low- and middle-income counties.

Syphilis in the Americas: a protocol for a systematic review of syphilis prevalence and incidence in four high-risk groups, 1980-2016

BACKGROUND

Syphilis infection has recently resurfaced as a significant public health problem. Although there has been a tremendous amount of research on the epidemiology of syphilis, there has been limited work done to synthesize the extensive body of research and systematically estimate patterns of disease within high-risk groups in the Americas. The purpose of this systematic review and meta-analysis is to (1) summarize recent patterns of syphilis infection in North and South America among four high-risk groups (MSM, transgender women, sex workers, and incarcerated individuals) from 1980 to 2016, (2) identify and differentiate regional geographic epidemiologic characteristics, and (3) compare the epidemics of the economically developed countries of North America from the developing countries and public health systems of Latin America and the Caribbean.

METHODS/DESIGN

Primary studies reporting syphilis prevalence and/or incidence in at least one of the four high-risk groups will be identified from Medline/PubMed, Embase, Lilacs, SciELO, The Cochrane Library, Web of Science, Scopus, ProQuest, CINAHL, Clase, and Periódica, as well as "gray" literature sources (conference abstracts, country reports, etc.). Studies published from 1980 through 2016 will be included. Data will be extracted from studies meeting inclusion and exclusion criteria and a random effects meta-analysis of prevalence and incidence estimates will be conducted. Heterogeneity, risk of bias, and publication bias will be assessed. Pooled prevalence and incidence estimates will be calculated for comparisons based on geographic region, risk factors, and time period.

DISCUSSION

Our systematic review and meta-analysis aims to contribute to an improved understanding of global epidemiologic patterns of syphilis infection in most-at-risk populations. Through systematic classification of the existing literature, and comparison of disease patterns across regional, temporal and socio-behavioral differences, we hope to improve public health surveillance and improve efforts to control the spread of disease across the Americas.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016047306.

Effect of HSV-2 infection on subsequent HIV acquisition: an updated systematic review and meta-analysis

Background

HIV and herpes simplex virus type 2 (HSV-2) infections cause a substantial global disease burden and are epidemiologically correlated. Two previous systematic reviews of the association between HSV-2 and HIV found evidence that HSV-2 infection increases the risk of HIV acquisition, but these reviews are now more than a decade old.

Methods

For this systematic review and meta-analysis, we searched PubMed, MEDLINE, and Embase (from Jan 1, 2003, to May 25, 2017) to identify studies investigating the risk of HIV acquisition after exposure to HSV-2 infection, either at baseline (prevalent HSV-2 infection) or during follow-up (incident HSV-2 infection). Studies were included if they were a cohort study, controlled trial, or case-control study (including case-control studies nested within a cohort study or clinical trial); if they assessed the effect of pre-existing HSV-2 infection on HIV acquisition; and if they determined the HSV-2 infection status of study participants with a type-specific assay. We calculated pooled random-effect estimates of the association between prevalent or incident HSV-2 infection and HIV seroconversion. We also extended previous investigations through detailed meta-regression and subgroup analyses. In particular, we investigated the effect of sex and risk group (general population vs higher-risk populations) on the relative risk (RR) of HIV acquisition after prevalent or incident HSV-2 infection. Higher-risk populations included female sex workers and their clients, men who have sex with men, serodiscordant couples, and attendees of sexually transmitted infection clinics.

Findings

We identified 57 longitudinal studies exploring the association between HSV-2 and HIV. HIV acquisition was almost tripled in the presence of prevalent HSV-2 infection among general populations (adjusted RR 2·7, 95% CI 2·2–3·4; number of estimates [N_e]=22) and was roughly doubled among higher-risk populations (1·7, 1·4–2·1; N_e=25). Incident HSV-2 infection in general populations was associated with the highest risk of acquisition of HIV (4·7, 2·2–10·1; N_e=6). Adjustment for confounders at the study level was often incomplete but did not significantly affect the results. We found moderate heterogeneity across study estimates, which was explained by risk group, world region, and HSV-2 exposure type (prevalent vs incident).

Interpretation

We found evidence that HSV-2 infection increases the risk of HIV acquisition. This finding has important implications for management of individuals diagnosed with HSV-2 infection, particularly for those who are newly infected. Interventions targeting HSV-2, such as new HSV vaccines, have the potential for additional benefit against HIV, which could be particularly powerful in regions with a high incidence of co-infection.

Funding

World Health Organization.

The Prevalence of Syphilis from the Early HIV Period is Correlated With Peak HIV Prevalence at a Country Level

BACKGROUND

Could we have predicted national peak HIV based on syphilis prevalence in the 1990s? Earlier studies have shown positive correlations between various sexually transmitted infections at different population levels. In this article, we test the hypothesis that there was a residual variation in the national prevalence rates of syphilis and that these rates could predict subsequent peak HIV prevalence rates.

METHODS

This analysis uses linear regression to evaluate the country-level relationship between antenatal syphilis prevalence (1990-1999) and peak HIV prevalence. Antenatal syphilis data were taken from an Institute for Health Metrics and Evaluation database on the prevalence of syphilis in low-risk populations. Peak HIV prevalence was calculated based on data taken from the Global Health Observatory Data Repository of the World Health Organization.

RESULTS

A moderately strong association is found for the 76 countries with data available (R = 0.53, P < 0.001). The association was weakened but remained significantly positive when we adjusted for the type of syphilis testing used.

CONCLUSIONS

Syphilis prevalence in the 1990s predicted approximately 53% of the variation in peak HIV prevalence. Populations with generalized HIV epidemics had a higher prevalence of syphilis in the pre-HIV period. This finding provides additional rationale to carefully monitor sexual behavior, sexual networks, and sexually transmitted infection incidence in these populations.

Epidemiology, clinical features, diagnosis and treatment of Haemophilus ducreyi - a disappearing pathogen?

Chancroid, caused by Haemophilus ducreyi, has declined in importance as a sexually transmitted pathogen in most countries where it was previously endemic. The global prevalence of chancroid is unknown as most countries lack the required laboratory diagnostic capacity and surveillance systems to determine this. H. ducreyi has recently emerged as a cause of chronic skin ulceration in some South Pacific islands. Although no antimicrobial susceptibility data for H. ducreyi have been published for two decades, it is still assumed that the infection will respond successfully to treatment with recommended cephalosporin, macrolide or fluoroquinolone-based regimens. HIV-1-infected patients require careful follow-up due to reports of treatment failure with single dose regimens. Buboes may need additional treatment with either aspiration or excision and drainage.

Quantitative and qualitative correlates of cervicovaginal herpes simplex virus type 2 shedding among HIV-infected women in the Women's Interagency HIV Study

We identified demographic, clinical and biological determinants of herpes simplex virus type 2 (HSV-2) shedding among HIV-infected participants in the Women's HIV Interagency Study (WIHS). Cervicovaginal lavage (CVL) specimens from 369 HIV-infected HSV seropositive women were tested with TaqMan polymerase chain reaction (PRC) for detection HSV-2 DNA. Seven percent of women tested positive for HSV-2 DNA in CVL. Significant correlates of the presence of HSV-2 DNA in CVL were being younger, African American or Hispanic race/ethnicity and injecting drugs in the past six months (P < 0.05). A borderline significant trend for reduced viral shedding with higher CD4+ T cell counts was observed (P = 0.08). All women who were never observed with any genital lesions and had consistently negative self-reported history of genital sores throughout the follow-up (n = 29, 8%) were negative for CVL HSV-2 DNA. HSV-2 DNA quantity was significantly associated with having frequent subsequent lesion recurrences (Spearman rho = 0.48, P = 0.016; adjusted prevalence ratio [APR] = 2.5, P = 0.012). Increasing the age of the host was inversely correlated with decreased viral shedding over time. However, a subset of older women continued to shed significant amounts of virus despite passage of time. This study provides genital HSV-2 DNA titre as a quantitative and symptom- and sign-based measures as qualitative predictors of HSV-2 shedding from the lower genital tract among HIV-infected women.

HIV infection and immune defense of the penis

Recent evidence that circumcision decreases HIV infection in heterosexual men by 50-60% has focused research on the foreskin as a target of HIV infection. In this review article, we discuss potential mechanisms underlying the circumcision effect and re-examine the assumption that the foreskin is the principle penile HIV infection site. HIV target cells are present in the foreskin epithelium, but are also found in the epithelia of the penile shaft, glans/corona, meatus and urethral introitus. Sexually transmitted infections (STIs) can affect any of these sites and increase susceptibility to HIV acquisition by eroding the protective epithelial layer and by attracting and activating HIV target cells in the epithelium. The moist subpreputial cavity, which encompasses the entire penile tip in most uncircumcised men including the glans, meatus and urethral introitus, plays an important role in STI acquisition. Circumcised men have a lower rate of STIs that infect not only the foreskin but also other distal penile sites, especially the urethra. Likewise, the foreskin may trap HIV and HIV-infected cells after intercourse thereby increasing the risk of HIV acquisition not only through the inner foreskin but also other sites covered by the foreskin. The subpreputial cavity also hosts a unique microbiome that may also play a role in HIV infection. We hypothesize that the penile urethra may be the primary HIV acquisition site in circumcised men and possibly also in non-circumcised men because of the presence of superficial HIV target cells and a high incidence of STIs at this site. Both innate and adaptive immune defense mechanisms are operative in the lower male genital region. The penile urethral mucosa contains accumulations of IgA(+) plasma cells and T lymphocytes and may provide a responsive target for future mucosal vaccines to prevent HIV sexual transmission.

Lymphogranuloma venereum: old pathogen, new story

Lymphogranuloma venerum (LGV), an ulcerative sexually transmitted infection caused by the L serovars of Chlamydia trachomatis, has gained recent attention as a cause of hemorrhagic proctitis among men who have sex with men in North America, the United Kingdom, and Europe. It has been a rare diagnosis, and likely has not been included in the routine differential diagnosis for proctocolitis. The lack of a specific diagnostic test has complicated LGV case ascertainment. In the absence of laboratory confirmation of L serovars, physicians are advised to treat possible cases presumptively for LGV and provide medical management of sexual partners. The appearance of an ulcerative infection in sexual networks with high rates of HIV coinfection may forewarn of increased HIV transmission; interruption of disease transmission remains a priority for medical providers and the public health community.

HIV-1, HSV-2 and syphilis among pregnant women in a rural area of Tanzania: prevalence and risk factors

BACKGROUND

Evidence suggests that a substantial proportion of new HIV infections in African countries are associated with herpes simplex virus type 2 (HSV-2). Thus, the magnitude of HSV-2 infection in an area may suggest the expected course of the HIV epidemic. We determined prevalence of genital herpes, syphilis and associated factors among pregnant women from a remote rural Tanzanian community that has a low but increasing HIV prevalence.

METHODS

We analysed 1296 sera and responses to a standard structured questionnaire collected from pregnant women aged between 15-49 years, attending six different antenatal clinics within rural Manyara and Singida regions in Tanzania. Linked anonymous testing (with informed consent) of the serum for specific antibodies against HSV-2 was done using a non-commercial peptide- 55 ELISA. Antibodies against syphilis were screened by using rapid plasma reagin (RPR) and reactive samples confirmed by Treponema pallidum haemagglutination assay (TPHA).

RESULTS

Previous analysis of the collected sera had shown the prevalence of HIV antibodies to be 2%. In the present study the prevalence of genital herpes and syphilis was 20.7% (95% CI: 18.53-23.00) and 1.6% (95% CI: 1.03-2.51), respectively. The presence of HSV-2 antibodies was associated with polygamy (OR 2.2, 95% CI: 1.62 - 3.01) and the use of contraceptives other than condoms (OR 1.7, 95% CI: 1.21 - 2.41). Syphilis was associated with reporting more than one lifetime sexual partner (OR 5.4, 95% CI: 1.88 - 15.76) and previous spontaneous abortion (OR 4.3, 95% CI: 1.52-12.02).

CONCLUSION

The low prevalence of HIV infection offers a unique opportunity for strengthening HIV prevention in a cost-effective manner. The identification and control of other prevalent curable STIs other than syphilis and specific intervention of HSV-2 in specific populations like pregnant women would be one among approaches towards preventing incident HIV infections.

Effect of genital ulcer disease on HIV-1 coreceptor expression in the female genital tract

OBJECTIVE

To examine the expression of human immunodeficiency virus type 1 (HIV-1) coreceptors (CCR5 and CXCR4) by monocytic cells within human genital ulcers.

METHODS

Women with primary or secondary syphilis, herpes simplex virus type 1 (HSV-1) or HSV-2 infection, or noninfectious abrasions had a biopsy sample taken from the lesion and contralateral vulva. HIV-1 coreceptor expression on CD3(+) and CD14(+) cells was analyzed by flow cytometry. Real-time reverse-transcriptase polymerase chain reaction was used to assess levels of coreceptor mRNA expression.

RESULTS

Women with primary or secondary syphilis or with HSV-1 or HSV-2 infection had significantly increased numbers of CD14(+) cells expressing CCR5 within the genital ulcer. This increase was also noted in the nonulcerated tissue isolated from women with syphilis and in peripheral blood mononuclear cells from women with secondary syphilis. CCR5 mRNA expression was increased in tissue obtained from syphilis lesions.

CONCLUSIONS

Monocytes recruited to genital ulcer disease (GUD) sites express increased levels of CCR5. This increased expression could account, at least in part, for enhanced HIV-1 transmission in the setting of GUD.

Patterns of HIV and syphilis infection in Northern Thailand 1998-2001

Northern Thailand has been the epicentre of a largely heterosexually transmitted HIV epidemic that has recently involved married women. In preparation for HIV-prevention trials, we investigated patterns of HIV and syphilis risk through annually measured HIV and syphilis prevalence among northern Thai, peri-urban, community-dwelling men (n=2564) and women (n=3907) aged 18-35 years between 1998 and 2001. Crude HIV and syphilis prevalence were 3.3% and 2.7% for men and 2.3% and 2.1% for women, respectively. In logistic regression models of HIV and syphilis, compared with married men/women, widowers and widows were at increased risk (odds ratio; 95% confidence interval) of syphilis (7.86; 1.56-39.6 and 3.3; 1.14-9.61, respectively) and HIV (12.68; 3.23-49.8 and 41.3; 24.3-70.3, respectively). The oldest women were at lower risk of HIV (0.43; 0.22-0.85). For men and women, those with syphilis were approximately three times more likely to have HIV. These unique population data illustrate evolving sex parity of HIV burden in northern Thailand.

Expression of Haemophilus ducreyi collagen binding outer membrane protein NcaA is required for virulence in swine and human challenge models of chancroid

Haemophilus ducreyi, the etiologic agent of the sexually transmitted genital ulcer disease chancroid, has been shown to associate with dermal collagen fibers within infected skin lesions. Here we describe NcaA, a previously uncharacterized outer membrane protein that is important for H. ducreyi collagen binding and host colonization. An H. ducreyi strain lacking the ncaA gene was impaired in adherence to type I collagen but not fibronectin (plasma or cellular form) or heparin. The mutation had no effect on serum resistance or binding to HaCaT keratinocytes or human foreskin fibroblasts in vitro. Escherichia coli expressing H. ducreyi NcaA bound to type I collagen, demonstrating that NcaA is sufficient to confer collagen attachment. The importance of NcaA in H. ducreyi pathogenesis was assessed using both swine and human experimental models of chancroid. In the swine model, 20% of lesions from sites inoculated with the ncaA mutant were culture positive for H. ducreyi 7 days after inoculation, compared to 73% of wild-type-inoculated sites. The average number of CFU recovered from mutant-inoculated lesions was also significantly reduced compared to that recovered from wild-type-inoculated sites at both 2 and 7 days after inoculation. In the human challenge model, 8 of 30 sites inoculated with wild-type H. ducreyi progressed to the pustular stage, compared to 0 of 30 sites inoculated with the ncaA mutant. Together these results demonstrate that the collagen binding protein NcaA is required for H. ducreyi infection.

High rates of syphilis among STI patients are contributing to the spread of HIV-1 in India

BACKGROUND

Recent syphilis outbreaks have raised concern regarding the potential enhancement of HIV transmission. The incidence of syphilis and its association with HIV-1 infection rates among a cohort of sexually transmitted infection (STI) clinic attendees was investigated.

METHODS

2732 HIV-1 seronegative patients attending three STI and one gynaecology clinic, were enrolled from 1993-2000 in an ongoing prospective cohort study of acute HIV-1 infection in Pune, India. At screening and quarterly follow up visits, participants underwent HIV-1 risk reduction counselling, risk behaviour assessment and HIV/STI screening that included testing for serological evidence of syphilis by RPR with TPHA confirmation. Patients with genital ulcers were screened with dark field microscopy.

RESULTS

Among 2324 participants who were HIV-1 and RPR seronegative at baseline, 172 participants were found to have clinical or laboratory evidence of syphilis during follow up (5.4 per 100 person years, 95% CI 4.8 to 6.5 per 100 person years). Independent predictors of syphilis acquisition based on a Cox proportional hazards model included age less than 20 years, lack of formal education, earlier calendar year of follow up, and recent HIV-1 infection. Based on a median follow up time of 11 months, the incidence of HIV-1 was 5.8 per 100 person years (95% CI 5.0 to 6.6 per 100 person years). Using a Cox proportional hazards model to adjust for known HIV risk factors, the adjusted hazard ratio of HIV-1 infection associated with incident syphilis was 4.44 (95% CI 2.96 to 6.65; p<0.001).

CONCLUSIONS

A high incidence rate of syphilis was observed among STI clinic attendees. The elevated risk of HIV-1 infection that was observed among participants with incident syphilis supports the hypothesis that syphilis enhances the sexual transmission of HIV-1 and highlights the importance of early diagnosis and treatment of syphilis.

Herpes simplex virus 2 infection increases HIV acquisition in men and women: systematic review and meta-analysis of longitudinal studies

OBJECTIVE

To estimate the sex-specific effect of herpes simplex virus type 2 (HSV-2) on the acquisition of HIV infection.

BACKGROUND

The increased number of longitudinal studies available since the last meta-analysis was published allows for the calculation of age- and sexual behaviour-adjusted relative risks (RR) separately for men and women.

DESIGN

Systematic review and meta-analysis of longitudinal studies.

METHODS

PubMed, Embase and relevant conference abstracts were systematically searched to identify longitudinal studies in which the relative timing of HSV-2 infection and HIV infection could be established. Where necessary, authors were contacted for separate estimates in men and women, adjusted for age and a measure of sexual behaviour. Summary adjusted RR were calculated using random-effects meta-analyses where appropriate. Studies on recent HSV-2 incidence as a risk factor for HIV acquisition were also collated.

RESULTS

Of 19 eligible studies identified, 18 adjusted for age and at least one measure of sexual behaviour after author contact. Among these, HSV-2 seropositivity was a statistically significant risk factor for HIV acquisition in general population studies of men [summary adjusted RR, 2.7; 95% confidence interval (CI), 1.9-3.9] and women (RR, 3.1; 95% CI, 1.7-5.6), and among men who have sex with men (RR, 1.7; 95% CI, 1.2-2.4). The effect in high-risk women showed significant heterogeneity, with no overall evidence of an association.

CONCLUSIONS

Prevalent HSV-2 infection is associated with a three-fold increased risk of HIV acquisition among both men and women in the general population, suggesting that, in areas of high HSV-2 prevalence, a high proportion of HIV is attributable to HSV-2.

Temporal trends of HIV-related risk behavior among Brazilian military conscripts, 1997-2002

PURPOSE

To present selected results of military conscript surveys related to HIV/AIDS, conducted in Brazil, 1997-2002.

METHODS

Questionnaires including information on socio-demographic data, sexual behavior practices, sexually transmitted infections-related problems, and use of injecting drugs were completed by 30970 individuals, obtained through a 2-stage sampling. An index of sexual risk behavior was developed to take into account multiplicity of partners and irregularity of condom use. The HIV infection prevalence rate was estimated for 2002. Logistic regression was used to identify the most important determinants of HIV infection.

RESULTS

The percentage of regular condom use increased from 38% (1997) to 49% (2002), and the index of sexual risk behavior decreased from 0.98 in 1997 to 0.87, in 2002. The HIV infection prevalence rate was 0.09%, in 2002, which remained unchanged since 1998 Riskier sexual practices among young men with incomplete education and among "men who have sex with men" were found as well as among the participants who reported at least one sexually transmitted infections - related problem. The most important predictor of HIV infection was to be positive for syphilis.

CONCLUSIONS

The estimated value of the HIV infection prevalence supports the diagnosis of a concentrated HIV epidemic, in Brazil. Results indicate that particular attention needs to be paid for regional differentials, and for special subgroups, in Brazil.

Metaanalysis and metaregression in interpreting study variability in the impact of sexually transmitted diseases on susceptibility to HIV infection

BACKGROUND

Observational studies examining the effects of other sexually transmitted diseases (STDs) on HIV susceptibility differ in the populations observed and in which "other STDs" are examined. The extent to which an STD alters the risk of transmission of HIV may vary according to disease and population characteristics.

GOALS

The goals of this study were to review studies examining the effect of other STDs on HIV-1 susceptibility and to correlate their effect estimates with type of "other STD", study design, and population characteristics.

STUDY

Relevant studies with longitudinal design were identified through a systematic search of the PubMed database, and their evidence was critically evaluated. Metaregression techniques were then used to correlate study characteristics with corresponding effect estimates.

RESULTS

Of 31 studies included, 4 contained direct data on exposure to HIV-1. Three of these were inconclusive, the fourth indicating a strong relationship between STDs and transmission of HIV. Pooled effect estimates using all studies are statistically significant and indicate a 2- to 3-fold increase in risk of HIV-1 acquisition. Effect estimates corresponding some of the "other STD" categories exhibit heterogeneity, but no significant associations with study characteristics were found.

CONCLUSIONS

Most of the studies lack direct exposure data, lending them susceptible to exposure bias. Another problem may be measurement error about risk factors and STD status at time of HIV-1 infection. Because direct exposure data are difficult to come by (4 of 31 studies contained such data, all but 1 inconclusive), future observational studies on the influence of STDs on HIV-1 transmission should include quantitative analyses of the sensitivity of results to potential confounding and measurement error if they are to further understanding.

Trichomonas vaginalis-induced epithelial monolayer disruption and human immunodeficiency virus type 1 (HIV-1) replication: implications for the sexual transmission of HIV-1

The objective of this study was to evaluate potential mechanisms of Trichomonas vaginalis involvement in human immunodeficiency virus type 1 (HIV-1) transmission. Polarized monolayer integrity of primary cervical and prostate epithelial cells or cell lines cultured with T. vaginalis was measured by monitoring transepithelium resistance. The effect of T. vaginalis isolates on HIV-1 passage through polarized epithelial cell monolayers was evaluated for HIV-1 p24gag in the basolateral supernatants. Coincubation with T. vaginalis isolates induced disruption of monolayer integrity and resulted in passage of virus to the basolateral side of the monolayer. Furthermore, there was isolate variability in which two isolates induced greater monolayer damage and increased HIV-1 passage than did the other two isolates. Coincubation of T. vaginalis isolates with acutely HIV-1-infected peripheral blood mononuclear cells enhanced HIV-1 replication. This enhancement was associated with cellular proliferation and activation, as well as with tumor necrosis factor alpha production. In contrast to the monolayer disruption, the effect of T. vaginalis on HIV-1 replication was not isolate dependent. Thus, two mechanisms have been identified that could contribute to the epidemiologic association of trichomoniasis with the sexual transmission of HIV-1. (i) T. vaginalis disruption of urogenital epithelial monolayers could facilitate passage of HIV-1 to underlying layers. (ii) Activation of local immune cells by T. vaginalis in the presence of infectious HIV-1 might lead to increased viral replication. Collectively, these data suggest the need for more vigilant efforts in the diagnosis and treatment of T. vaginalis in women and men, especially in countries with a high prevalence of HIV-1.

The role of sexually transmitted diseases in HIV transmission

More than 42 million people worldwide are now infected with HIV, in spite of sustained prevention activities. Although the spread of HIV has been primarily sexual, epidemiological studies have indicated that the efficiency of the spread of HIV is poor, perhaps as infrequently as 1 in every 1,000 episodes of sexual intercourse. However, sexually transmitted diseases (STDs) that cause ulcers or inflammation greatly increase the efficiency of HIV transmission--by increasing both the infectiousness of, and the susceptibility to HIV infection. STDs might be particularly important in the early stages of a localized HIV epidemic, when people with risky sexual behaviour are most likely to become infected. In China, eastern Europe and Russia, there has been a remarkable increase in the incidence of STDs in recent years, and this is reflected in the rapid increase in the spread of HIV in these areas. Targeted STD detection and treatment should have a central role in HIV prevention in these emerging epidemics.

Etiology of genital ulcer disease and association with human immunodeficiency virus infection in two tanzanian cities

BACKGROUND

The etiological agent is usually not established in cases of genital ulcer disease (GUD) in Tanzania, since diagnosis and treatment of this disease are based mainly on clinical rather than microbiologic parameters. GUD increases the risk of infection with HIV. However, the association between specific GUD infections and HIV infection has not been fully investigated.

GOAL

The goal was to determine the etiology of GUD and the prevalence of HIV infection in patients with GUD in urban areas of Tanzania.

STUDY DESIGN

A total of 102 clinical specimens were collected from 52 and 50 patients with GUD in Dar es Salaam and Mbeya, respectively, and from 93 patients with genital discharge in a cross-sectional study. Two polymerase chain reaction (PCR) assays were used to identify either a single target DNA or all three DNAs of the major causes of GUD: Haemophilus ducreyi, Treponema palladum and herpes simplex virus type 2 (HSV-2). The sera from all patients were tested for antibodies to HIV and T palladum.

RESULTS

In Dar es Salaam, DNA from HSV-2, and was detected in 63%, 13%, and 2%, respectively, of the 52 genital ulcer specimens. The corresponding figures in Mbeya were 34%, 10%, and 0% of 50 specimens. Overall, 9% of the 102 patients with GUD were infected with both HSV-2 and, and 39/102 genital ulcer specimens (38%) were negative for the DNA of all three pathogens. The HIV infection rates among GUD patients were 46% and 52% in Dar es Salaam and Mbeya, respectively; among the non-GUD patients, the corresponding rates were 35% and 45%, respectively. The HIV infection rate in Dar es Salaam was significantly higher among women (11/14; 78%) than among men (13/38; 34%) (P = 0.004). Among the HIV-seropositive GUD patients, 71% and 46% (P < 0.003) were coinfected with HSV-2 in Dar es Salaam and Mbeya, respectively. Furthermore, women with HSV-2 in Dar es Salaam were significantly more likely to be HIV-infected than men (60% versus 39%; P<or= 0.006). antibodies were detected in 27 (26%) of the 102 GUD patients and 16 (17%) of the 93 non-GUD patients.

CONCLUSION

HSV-2 was the most commonly identified agent in the genital ulcer specimens in two urban STD clinics in Tanzania. The prevalence of HIV was high among the STD patients. HSV-2 was detected at significantly higher rates among HIV-seropositive than HIV-seronegative patients with GUD in both Dar es Salaam and Mbeya.

Drug use patterns and infection with sexually transmissible agents among young adults in a high-risk neighbourhood in New York City

AIMS

To determine relationships between drug use "hardness" (defined in increasing order of hardness as no drug use, marijuana use, non-injected heroin or cocaine use, crack smoking and injection drug use) and prevalences of several sexually transmissible infections among young adults in a high-risk neighbourhood. Drug users, particularly injection drug users and crack smokers, may be a core group for some sexually transmitted infections.

DESIGN

Cross-sectional survey and assays of young adults from (a) a household probability sample and (b) a targeted sample of youth who have used injected drugs, crack, other cocaine or heroin.

SETTING

Bushwick, an impoverished New York City minority neighbourhood with major drug markets.

PARTICIPANTS

A total of 363 18-24-year-olds from a household probability sample; 165 Bushwick 18-24-year-olds who have used injected drugs, crack, other cocaine or heroin.

MEASUREMENTS

Drug use by self-report; serum- and urine-based assays for HIV, hepatitis B and C, syphilis, gonorrhoea, chlamydia and herpes simplex (type 2).

FINDINGS

Household-sample prevalences: HIV, hepatitis C and syphilis, 1%; gonorrhoea 3%; chlamydia 5%; past or present hepatitis B infection 8%; herpes simplex (type 2) 18%. In combined household and targeted samples, hepatitis C and HIV were concentrated among drug injectors. Herpes simplex (type 2), syphilis and hepatitis B increased among women with "hardest drug ever used".

CONCLUSIONS

Using "harder" drugs is associated with some but not all of these infections. Prevention efforts should help youth avoid unsafe sex and higher-risk drugs.

Age-specific prevalence of infection with herpes simplex virus types 2 and 1: a global review

Information on age- and sex-specific prevalence of herpes simplex virus (HSV) types 2 and 1 infections is essential to optimize genital herpes control strategies, which increase in importance because accumulating data indicate that HSV-2 infection may increase acquisition and transmission of human immunodeficiency virus. This review summarizes data from peer-reviewed publications of type-specific HSV seroepidemiologic surveys. HSV-2 prevalence is, in general, highest in Africa and the Americas, lower in western and southern Europe than in northern Europe and North America, and lowest in Asia. HSV-2 and -1 prevalence, overall and by age, varies markedly by country, region within country, and population subgroup. Age-specific HSV-2 prevalence is usually higher in women than men and in populations with higher risk sexual behavior. HSV-2 prevalence has increased in the United States but national data from other countries are unavailable. HSV-1 infection is acquired during childhood and adolescence and is markedly more widespread than HSV-2 infection. Further studies are needed in many geographic areas.

Estimating the magnitude of STD cofactor effects on HIV transmission: how well can it be done?

BACKGROUND

If sexually transmitted disease (STD) cofactor effects are strong and STDs are highly prevalent, STD control can be a strategy for HIV prevention.

OBJECTIVE

To review possibilities for estimating cofactor effects of STDs on HIV transmission based on observational studies.

STUDY DESIGN

This study consisted of an analysis of factors influencing associations between HIV and STDs, which can bias STD cofactor studies, from a sexual network perspective. Study designs that reduce distortions and methods to improve estimates in the presence of confounding are discussed.

RESULTS

Standard statistical adjustments of cofactor estimates are insufficient because they ignore clustering between HIV and STDs in partners of study subjects, resulting from population heterogeneity in risk factors and assortative mixing. Reverse causation due to HIV-related immunosuppression may further inflate cofactor estimates. Misclassification of STDs and clustering between STDs can bias estimates in either direction. This study demonstrates quantitatively that ignorance of sexual network effects may result in considerable overestimation of cofactor magnitudes.

CONCLUSION

The limitations of observational studies complicate quantitative inferences on the role of STDs in HIV transmission.

A systematic review of the epidemiologic interactions between classic sexually transmitted diseases and HIV: how much really is known?

BACKGROUND

Many studies have explored the role of "classic" sexually transmitted diseases (STDs) in determining the pattern of HIV epidemics. However, the many different STDs may contribute in different ways, at different magnitudes.

GOAL

To review available studies on the bidirectional interactions of HIV and STDs to explore the extent of current knowledge on the different influences of the varied STDs in heterosexual HIV epidemics.

METHODS

Longitudinal studies on susceptibility and controlled studies on infectiousness and duration of disease identified on electronic databases through reference lists and citation indices up to the end of 1999 were systematically reviewed, including meta-analyses assessing the influence of STDs on susceptibility to HIV.

RESULTS

Studies have a clear publication bias with a significant result that hinders robust interpretation. However, genital ulcerative disease appears to have a greater impact than nonulcerative disease, and men are more affected than women by the effects of STDs on susceptibility to HIV. There is evidence that STDs increase the infectiousness of HIV from men to women, whereas the evidence is more equivocal for the infectiousness of women. Few studies identify the impact of different STDs, and there is a marked lack of studies investigating the impact of HIV infection on the transmission of other STDs.

CONCLUSIONS

A large body of work has measured the association between STDs and HIV. However, publication bias and gaps in the focus of studies mean that a detailed, quantitative understanding of the interaction requires much more attention.

Prevalence of herpes simplex type 2 and syphilis serology among young adults in a rural Gambian community

OBJECTIVES

To estimate prevalence and risk factors for herpes simplex 2 (HSV2) positivity, syphilis and Chlamydia trachomatis infection among rural people aged 15-34 in the Gambia.

METHODS

Questionnaires and serum samples were collected from 1076 men and women aged 15-34 during a cross sectional prevalence survey in a rural area of the Gambia. Sera were screened for antibodies to herpes simplex virus type 2 (HSV2), and for syphilis using Treponema pallidum haemagglutination assay (TPHA) and rapid plasma reagin (RPR) tests. Urine was tested by polymerase chain reaction (PCR) for C trachomatis infection.

RESULTS

28% of women and 5% of men were HSV2 ELISA positive; 10% of women and 2% of men were TPHA positive; and 7% of women and 1% of men were both RPR and TPHA positive. Out of 1030 urine sample tested only six were positive for C trachomatis. 7% of those who reported never having sex were positive for one or other of these tests. Prevalences of all STIs increased with age and were higher in women than men. Women were much less likely than men to seek treatment for STI symptoms at a health centre. Married people were at increased risk of an STI compared with single people. Jola and Fula women had a higher prevalence of HSV2 than women from other ethnic groups, and Fulas also had a higher prevalence of RPR/TPHA positivity. The limited number of sexual behaviour questions were not significantly associated with STIs after adjustment for age, marital status, and ethnic group.

CONCLUSIONS

The prevalences of the ulcerative infections HSV2 and syphilis in this population are a cause for concern. In a setting where HIV1 prevalence remains low this indicates an urgent need for STI control and behaviour change programmes to prevent an HIV epidemic. Concerns about the validity of reported sexual behaviour data high light the necessity of biological markers in the evaluation of behaviour change programmes.

Ecological and individual level analysis of risk factors for HIV infection in four urban populations in sub-Saharan Africa with different levels of HIV infection

OBJECTIVE

To identify factors that could explain differences in rate of spread of HIV between different regions in sub-Saharan Africa.

DESIGN

Cross-sectional study.

METHODS

The study took place in two cities with a relatively low HIV prevalence (Cotonou, Benin and Yaoundé, Cameroon), and two cities with a high HIV prevalence (Kisumu, Kenya and Ndola, Zambia). In each of these cities, a representative sample was taken of about 1000 men and 1000 women aged 15-49 years. Consenting men and women were interviewed about their socio-demographic background and sexual behaviour; and were tested for HIV, herpes simplex virus type 2 (HSV-2), syphilis, Chlamydia trachomatis and Neisseria gonorrhoea infection, and (women only) Trichomonas vaginalis. Analysis of risk factors for HIV infection was carried out for each city and each sex separately. Adjusted odds ratios (aOR) were obtained by multivariate logistic regression.

RESULTS

The prevalence of HIV infection in sexually active men was 3.9% in Cotonou, 4.4% in Yaoundé, 21.1% in Kisumu, and 25.4% in Ndola. For women, the corresponding figures were 4.0, 8.4, 31.6 and 35.1%. High-risk sexual behaviour was not more common in the high HIV prevalence cities than in the low HIV prevalence cities, but HSV-2 infection and lack of circumcision were consistently more prevalent in the high HIV prevalence cities than in the low HIV prevalence cities. In multivariate analysis, the association between HIV infection and sexual behavioural factors was variable across the four cities. Syphilis was associated with HIV infection in Ndola in men [aOR = 2.7, 95% confidence interval (CI) = 1.5-4.91 and in women (aOR = 1.7, 95% CI = 1.1-2.6). HSV-2 infection was strongly associated with HIV infection in all four cities and in both sexes (aOR ranging between 4.4 and 8.0). Circumcision had a strong protective effect against the acquisition of HIV by men in Kisumu (aOR = 0.25, 95% CI = 0.12-0.52). In Ndola, no association was found between circumcision and HIV infection but sample sizes were too small to fully adjust for confounding.

CONCLUSION

The strong association between HIV and HSV-2 and male circumcision, and the distribution of the risk factors, led us to conclude that differences in efficiency of HIV transmission as mediated by biological factors outweigh differences in sexual behaviour in explaining the variation in rate of spread of HIV between the four cities.

The epidemiology of HSV-2 infection and its association with HIV infection in four urban African populations

OBJECTIVES

To estimate age- and sex-specific herpes simplex virus type-2 (HSV-2) prevalence in urban African adult populations and to identify factors associated with infection.

DESIGN AND METHODS

Cross-sectional, population-based samples of about 2000 adults interviewed in each of the following cities: Cotonou, Benin; Yaoundé, Cameroon; Kisumu, Kenya and Ndola, Zambia. Consenting study participants were tested for HIV, HSV-2 and other sexually transmitted infections.

RESULTS

HSV-2 prevalence was over 50% among women and over 25% among men in Yaoundé, Kisumu and Ndola, with notably high rates of infection among young women in Kisumu and Ndola (39% and 23%, respectively, among women aged 15-19 years). The prevalence in Cotonou was lower (30% in women and 12% in men). Multivariate analysis showed that HSV-2 prevalence was significantly associated with older age, ever being married, and number of lifetime sexual partners, in almost all cities and both sexes. There was also a strong, consistent association with HIV infection. Among women, the adjusted odds ratios for the association between HSV-2 and HIV infections ranged from 4.0 [95% confidence interval (CI) = 2.0-8.0] in Kisumu to 5.5 (95% CI = 1.7-18) in Yaoundé, and those among men ranged from 4.6 (95% CI = 2.7-7.7) in Ndola to 7.9 (95% CI = 4.1-15) in Kisumu.

CONCLUSIONS

HSV-2 infection is highly prevalent in these populations, even at young ages, and is strongly associated with HIV at an individual level. At a population level, HSV-2 prevalence was highest in Kisumu and Ndola, the cities with the highest HIV rates, although rates were also high among women in Yaoundé, where there are high rates of partner change but relatively little HIV infection. The high prevalence of both infections among young people underlines the need for education and counselling among adolescents.

The clinical manifestations and treatment of sexually transmitted diseases in human immunodeficiency virus-positive men

Sexually transmitted diseases (STDs) occur commonly in sexually active human immunodeficiency virus (HIV)-positive men. STDs may have atypical presentations, can cause significant morbidity in persons with HIV infection, and may increase the risk of HIV transmission. Thus, the appropriate diagnosis and treatment of STDs in this population are extremely important. The clinical manifestations and treatment of several common STDs in HIV-positive men are reviewed. Further research is needed to define effective management and screening strategies for STDs in men with HIV infection.

Diagnosing genital ulcer disease in a clinic for sexually transmitted diseases in Amsterdam, The Netherlands

The most common etiologic agents of genital ulcer disease (GUD) are herpes simplex virus type 1 (HSV-1), HSV-2, Treponema pallidum, and Haemophilus ducreyi. In an outpatient clinic for sexually transmitted diseases in Amsterdam, The Netherlands, specimens from 372 patients with GUD were collected from February to November 1996. Sera were collected at the time of the symptoms and, for most patients, also during follow-up visits. Swabs in viral transport medium were used for HSV culture and for detection of DNA. The most prevalent pathogen found was HSV-2, which was detected by culture in 35% of the patients and by PCR in 48% of the patients. Also, HSV-1 infection was more often detected by PCR (7.8%) than by culture (5.6%). Evidence for an active infection with T. pallidum was found in 1.9% of the patients, using serological tests. A multiplex PCR for simultaneous T. pallidum and H. ducreyi DNA detection was positive for T. pallidum in 3.3% of the samples and for H. ducreyi in only 0.9% (3 out of 368) of the samples. The sensitivity of the PCR was superior to that of culture for HSV detection and to that of serology for T. pallidum detection. Specific H. ducreyi immunoglobulin G antibodies were detected in sera of 5.2% of the patients, with no concordance between serology and PCR. In 37% of the cases, none of the tested microorganisms was detected. Performance of PCR in addition to conventional techniques significantly improved the diagnosis of GUD.

Sexually transmitted infections, adverse pregnancy outcome and neonatal infection

Prevention and treatment of sexually transmitted infections (STIs) in the sexually active population are the main steps to prevent perinatal infection. However, the spread of STIs continues at an astronomical pace despite various attempts at controlling the epidemic. An important reason for this lack of STI control is that a large percentage of infected people go untreated because they have asymptomatic or unrecognized infections. The microbial differential diagnosis of STIs implicated in adverse pregnancy outcome is broad and includes viral, bacterial and protozoal infections. Infertility, ectopic pregnancy, pelvic inflammatory disease, chorioamnionitis, premature rupture of membranes, preterm birth and puerperal sepsis are some of complications seen in women as a result of infection with sexually transmitted pathogens. In addition, STIs may facilitate the acquisition and transmission of HIV. In the fetus or neonate, complications include abnormalities of the major organ systems. Infections in the form of pneumonia or conjunctivitis may also occur. Due to the lack of simple, inexpensive and sensitive point-of-care tests, screening for STIs in pregnancy is not performed routinely.

Prevalence and correlates of herpes simplex virus type 2 infection in a population-based survey of young women in low-income neighborhoods of Northern California. The Young Women's Survey Team

BACKGROUND

Herpes simplex virus type 2 (HSV-2) is one of the most common sexually transmitted infections and may enhance transmission of HIV. However, population-based estimates of HSV-2 prevalence and correlates of infection are rare.

GOALS

To obtain population-based estimates of HSV-2 prevalence and to identify demographic and sexual behavioral correlates of infection among women in low-income communities of Northern California.

STUDY DESIGN

A randomized, single-stage, cluster sample, cross-sectional survey of women age 18 to 29 years who reside in 1990 US Census block groups at the lowest tenth percentile for household income.

RESULTS

The survey-weighted prevalence of HSV-2 infection was 34.8% (95% CI, 30.4-39.2). Factors independently associated with HSV-2 seropositivity were black race, older age, lower income, parity, greater number of lifetime male sexual partners, earlier onset of sexual intercourse, sex work, history of sexually transmitted disease (STD), and cocaine use.

CONCLUSION

The high prevalence of HSV-2 and the strong correlation with sexual risk underscores the potential for further spread of STD, including HIV, in this young population.

Sexually transmitted diseases and the increased risk for HIV transmission: implications for cost-effectiveness analyses of sexually transmitted disease prevention interventions

We estimated the annual number and cost of new HIV infections in the United States attributable to other sexually transmitted diseases (STDs). We used a mathematical model of HIV transmission to estimate the probability that a given STD infection would facilitate HIV transmission from an HIV-infected person to his or her partner and to calculate the number of HIV infections due to these facilitative effects. In 1996, an estimated 5,052 new HIV cases were attributable to the four STDs considered here: chlamydia (3,249 cases), syphilis (1,002 cases), gonorrhea (430 cases), and genital herpes (371 cases). These new HIV cases account for approximately $985 million U.S. in direct HIV treatment costs. The model suggested that syphilis is far more likely than the other STDs (on a per-case basis) to facilitate HIV transmission. This analysis provides a framework for incorporating STD-attributable HIV treatment costs into cost-effectiveness analyses of STD prevention programs.

Human immunodeficiency virus infection and genital ulcer disease in South Africa: the herpetic connection

BACKGROUND AND OBJECTIVES

While genital ulcers are a risk factor in HIV infection, the association of specific agents of genital ulcer disease (GUD) with HIV infection may vary.

GOAL

To determine the etiology of GUD in HIV-infected and HIV-uninfected men attending sexually transmitted disease (STD) clinics in Durban, Johannesburg, and Cape Town, South Africa, and the association of previous and current sexually transmitted infections with HIV infection in men with ulcerative and nonulcerative STDs.

STUDY DESIGN

A cross-sectional study of 558 men with genital ulcers and 602 men with urethritis.

RESULTS

Patients with GUD were more likely to be infected with HIV than patients with urethritis (39.4% versus 21.4%, P< or =0.001). Herpes simplex virus 2 (HSV-2) was the most common agent identified in ulcer specimens (35.9%), and was detected in a significantly higher proportion of ulcer specimens from HIV-infected patients than in specimens from HIV-uninfected patients (47.4% versus 28.2%, P< or =0.001). Patients infected with HIV-1 were significantly more likely to have HSV-2 infection, as measured by the presence of the antibody to glycoprotein G-2, than patients not infected with HIV (63.1% versus 38.5%, P< or =0.001). Patients infected with HIV-1 were also significantly more likely to have initial HSV-2 infection than HIV-uninfected patients with GUD (50.0% versus 31.6%, P = 0.007). Haemophilus ducreyi was detected in 31.7% of ulcer specimens; prevalence did not vary by HIV-infection status. Treponema pallidum DNA was detected significantly less frequently in ulcer specimens from patients infected with HIV than in specimens from patients not infected with HIV (10.2% versus 26%, P< or =0.001); no association was found between HIV-infection status and fluorescent treponemal antibody absorption test seroreactivity, even when men with M-PCR-positive syphilis lesions were excluded from the analyses.

CONCLUSION

The authors found that HSV-2 is a more common etiology of GUD than has been suggested by previous studies conducted in South Africa; serologic evidence of HSV-2 infection and current cases of genital herpes are strongly associated with HIV infection among men who present to STD clinics with GUD or urethritis.

Increasing prevalence of genital herpes in developing countries: implications for heterosexual HIV transmission and STI control programmes

BACKGROUND

The recognition that sexually transmitted infections (STI) facilitate HIV transmission among heterosexuals has led to a rejuvenated focus on improving STI control as a component of HIV prevention programmes in developing countries. While efforts so far have focused mainly on all STI, there is increasing evidence that genital ulcers facilitate a considerable proportion of HIV transmission among heterosexuals and that this effect has been underestimated. This paper focuses on the epidemiology of genital herpes in developing countries past and present.

OBJECTIVES

To review the scientific literature about the epidemiology of genital herpes in developing countries and discuss the implications of the findings for STI control and HIV prevention programmes. SEARCH METHODOLOGY: A Medline search for June 1966 to August 1999 using the keywords, genital herpes, STD and developing countries, and genital ulcers in MeSH and free text. Abstract books from recent international AIDS conferences and other international STD conferences were reviewed. The annual reports of the medical officers of heath for Harare 1982-1998 and Durban 1989-1997 were reviewed to detect trends in genital herpes diagnoses.

FINDINGS

Genital herpes, formerly regarded as a minor STI in most developing countries, has now emerged as a leading cause of genital ulceration in many countries where syphilis and chancroid were more prevalent previously. This increased recognition of genital herpes reflects both a change in the pattern of STI epidemiology through a decline in syphilis and chancroid as a response to HIV control programmes and improved techniques for diagnosing herpetic infection. Countries with significant heterosexual HIV epidemics also appear to have rapidly increasing numbers of genital herpes cases.

CONCLUSIONS

The emergence of this herpes epidemic must be addressed through innovative strategies that will be viable, sustainable, acceptable, and effective in developing countries. In countries where genital herpes is a significant problem, local adaptation of WHO treatment algorithms should be made. STI service providers should be trained about issues around the transmission of herpes and how best to advise clients about dealing with, and recognising, recurrences. The effectiveness of antiviral treatment for genital herpes should be investigated in core groups at high risk of HIV.

Herpes in the time of AIDS: a comparison of the epidemiology of HIV-1 and HSV-2 in young men in northern Thailand

OBJECTIVES

To compare the epidemiologic pattern of HIV-1, a recently introduced sexually transmitted disease (STD) agent in Thailand, with the pattern of HSV-2, a well-established STD agent, so that future trends for both viruses can be better understood.

METHODS

We obtained questionnaire data and determined HSV-2 (by specific gG-2) and HIV-1 seroreactivity in a cohort of 1,115 young male army conscripts who entered service in northern Thailand in 1991.

RESULTS

Seroprevalence of HIV-1 and HSV-2 was 6.9% and 14.9%, respectively. For HSV-2-seropositive men who reported previous genital ulcers, HIV-1 seroprevalence was 32%. For most variables, there was a close correspondence between the prevalence ratios for HIV-1 and for HSV-2, except that prevalence ratios for HIV-1 tended to be greater than the corresponding ratios for HSV-2. The seroprevalence of both viruses was strongly related to early and frequent contact with female sex workers (FSWs), infrequent use of condoms with FSWs, and residence in the upper north region of Thailand. When differences in sexual behavior between the upper north and lower north were controlled for, the seroprevalence of both viruses still differed significantly by region.

CONCLUSIONS

Although the seroprevalence levels of HSV-2 and HIV-1 were quite different in this cohort of Thai army conscripts in 1991, the patterns of infection in terms of demographic, residential, and behavioral variables were similar. Seroprevalence studies of HSV-2 in other populations, particularly where the HIV-1 epidemic is just beginning, may be useful in predicting which subgroups might be most vulnerable to the epidemic and could therefore benefit the most from public health intervention. Where differences in the patterns of the two viruses have been noted, we hypothesize that the pattern for HIV-1 will evolve toward that seen for HSV-2.

From epidemiological synergy to public health policy and practice: the contribution of other sexually transmitted diseases to sexual transmission of HIV infection

OBJECTIVES

To review the scientific data on the role of sexually transmitted diseases (STDs) in sexual transmission of HIV infection and discuss the implications of these findings for HIV and STD prevention policy and practice.

METHODS

Articles were selected from a review of Medline, accessed with the OVID search engine. The search covered articles from January 1987 to September 1998 and yielded 2101 articles. Methods used to uncover articles which might have been missed included searching for related articles by author, and combing literature reviews. In addition, all abstracts under the category "sexually transmitted diseases" from the XI and XII International Conferences on AIDS (Vancouver 1996 and Geneva 1998) and other relevant scientific meetings were reviewed. Efforts were made to locate journal articles which resulted from the research reported in the identified abstracts. All original journal articles and abstracts which met one of the following criteria were included: (1) studies of the biological plausibility or mechanism of facilitation of HIV infectiousness or susceptibility by STDs, (2) prospective cohort studies (longitudinal or nested case-control) which estimate the risk of HIV infection associated with specific STDs or STD syndromes, or (3) intervention studies which quantitate the effect which STD treatment can have on HIV incidence.

RESULTS

Strong evidence indicates that both ulcerative and non-ulcerative STDs promote HIV transmission by augmenting HIV infectiousness and HIV susceptibility via a variety of biological mechanisms. These effects are reflected in the risk estimates found in numerous prospective studies from four continents which range from 2.0 to 23.5, with most clustering between 2 and 5. The relative importance of ulcerative and non-ulcerative STDs appears to be complex. Owing to the greater frequency of non-ulcerative STDs in many populations, these infections may be responsible for more HIV transmission than genital ulcers. However, the limited reciprocal impact of HIV infection on non-ulcerative STDs and the evidence that non-ulcerative STDs may increase risk primarily for the receptive partner (rather than bidirectionally) may modulate the impact of these diseases. The results of two community level randomised, controlled intervention trials conducted in Africa suggest that timely provision of STD services can substantially reduce HIV incidence, but raise additional questions about the optimal way to target and implement these services to achieve the greatest effect on HIV transmission.

CONCLUSIONS

Available data leave little doubt that other STDs facilitate HIV transmission through direct, biological mechanisms and that early STD treatment should be part of a high quality, comprehensive HIV prevention strategy. Policy makers, HIV prevention programme managers, and providers should focus initial implementation efforts on three key areas: (i) improving access to and quality of STD clinical services; (ii) promoting early and effective STD related healthcare behaviours; and (iii) establishing surveillance systems to monitor STD and HIV trends and their interrelations.