Genital ulceration as a risk factor for human immunodeficiency virus infection

Syphilis Prevalence Among People Living With and Without HIV in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

BACKGROUND

Syphilis is a curable sexually transmitted infection that, untreated, is associated with significant morbidity and mortality. In people living with HIV (PLWH), syphilis carries greater risks of disease progression. We estimated syphilis prevalence among PLWH in the general population in sub-Saharan Africa and compared the prevalence among PLWH and without HIV.

METHODS

We searched for studies published January 1, 2011, to March 28, 2022, reporting syphilis prevalence among PLWH in sub-Saharan Africa (PROSPERO No. CRD42020167328). We excluded studies in high-risk subpopulations. We estimated pooled syphilis prevalence among PLWH using random-effects modeling and compared the prevalence with people without HIV when included in the same study. We examined influences of region, study setting, and test type in subgroup analyses.

RESULTS

We identified 926 studies; 53 were included in the meta-analysis. Pooled syphilis prevalence among PLWH was 7.3% (95% confidence interval [CI], 6.3%-8.5%). Prevalence differed by region: 3.1% (95% CI, 2.2%-4.0%) in Southern, 5.5% (95% CI, 2.3%-9.3%) in West/Central, and 10.5% (95% CI, 8.0%-13.1%) in Eastern Africa. Prevalence also differed by study setting: 13.8% (95% CI, 5.7%-23.0%) in sexual and reproductive health/sexually transmitted infection care, 8.7% (95% CI, 5.0%-12.8%) in HIV care, 7.1% (95% CI, 5.8%-8.5%) in antenatal care, and 3.8% (95% CI, 2.0%-5.8%) in household/community-based settings. Syphilis prevalence was higher among PLWH than without HIV (relative risk, 3.5; 95% CI, 2.8-4.5).

CONCLUSIONS

Syphilis is highly prevalent among PLWH in sub-Saharan Africa and is more common among PLWH than without HIV. Integration of syphilis screening and management into HIV care may reduce complications of HIV-syphilis coinfection among PLWH in sub-Saharan Africa.

Vaginal delivery of vaccines

Recent estimates suggest that one in two sexually active individuals will acquire a sexually transmitted infection by age 25, an alarming statistic that amounts to over 1 million new infections per day worldwide. Vaccination against STIs is highly desirable for alleviating this global burden of disease. Vaginal immunization is a promising strategy to combat transmission via the vaginal mucosa. The vagina is typically considered a poor inductive site for common correlates of adaptive immunity. However, emerging evidence suggests that immune tolerance may be overcome by precisely engineered vaccination schemes that orchestrate cell-mediated immunity and establish tissue resident memory immune cells. In this review, we will discuss the unique immunological milieu of the vaginal mucosa and our current understanding of correlates of pathogenesis and protection for several common STIs. We then present a summary of recent vaginal vaccine studies and explore the role that mucosal adjuvants and delivery systems play in enhancing protection according to requisite features of immunity. Finally, we offer perspectives on the challenges and future directions of vaginal vaccine delivery, discussing remaining physiological barriers and innovative vaccine formulations that may overcome them.

Syphilis seroprevalence and seroconversion among people newly diagnosed with HIV during the pre-antiretroviral therapy period in rural China

Syphilis has a high incidence among people living with HIV (PLHIV), which may be attributable to their similar sexual transmission route. A retrospective cohort study was conducted during the period 2009-2015 to investigate the syphilis seroprevalence and incidence of syphilis seroconversion among newly-diagnosed PLHIV in rural Yunnan, China. Recent HIV infection among PLHIV was identified by BED capture enzyme immunoassay. PLHIV were followed until they initiated antiretroviral therapy. Syphilis serology was conducted at baseline and each follow-up over the study period. Among 2162 participants, the syphilis seroprevalence at baseline was 2.7%, 95% confidence interval (CI) (2.4-3.1). Single and divorced (versus married) (aOR = 2.9, [1.1-7.4]; 5.9, [2.4-14.7], respectively), employed in the service industry (versus unemployed) (2.8, [1.4-5.6]), being diagnosed with HIV in hospitals (versus voluntary counselling and testing) (5.1, [2.0-12.9]), recent HIV infection (17.9, [8.5-37.9]) and inconsistent condom use in the previous three months (versus consistent condom use) (6.2, [2.8-13.4]) were associated with higher risk of syphilis infection at baseline. Participants contributed 1955.4 person-years (PYs) of follow-up, with a median follow-up period of 0.9 years (IQR: 0.5-1.9) and the incidence of syphilis seroconversion was 2.2 (95% CI 1.5-2.9) per 100 PYs. The syphilis seroprevalence at baseline (aHR 3.7, [1.8-7.9]), had a HIV-negative partner at baseline (3.9, [1.5-9.8]) and inconsistent condom use in the last three months at baseline (6.0, [1.4-25.4]) were associated with higher risk of syphilis seroconversion. Our findings indicate that the public health response should be escalated to minimise the spread of syphilis co-infection among PLHIV and reducing condomless sexual behaviours after HIV diagnosis.

Girinimbine from curry leaves promotes gastro protection against ethanol induced peptic ulcers and improves healing via regulation of anti-inflammatory and antioxidant mechanisms

Curry leaves (Murraya koenigii) are a leafy spice used in Indian cookery for its fragrant aroma. Many bioactive functional compounds have been identified, and among them carbazole alkaloids have attracted wide attention due to their multi-dimensional medicinal value. Even though it has been established that the carbazole alkaloid is responsible for the anti-ulcer effect showed by this culinary herb, there is no further evidence to say which phytochemical is responsible for this. In the present study, we investigated the gastro-protective effects and mechanism of girinimbine, a major carbazole alkaloid present in curry leaves. Rats were administered with ethanol to produce gastric ulcers, and the prophylactic effect of girinimbine was evaluated. A macroscopic and histological examination was carried out to examine the lesions. Furthermore, the mucus production, NO production, PGE2 synthesis, mucosal nonprotein sulphydryls, glutathione (GSH) level, lipid peroxidation (MDA) level and COX inhibition were assessed. In addition, in particular, TNF-α and IL-6, two important cytokines, were evaluated. Immunohistochemical and gene expression studies were conducted to determine the HSP70 and iNOS biomarkers. Our results indicated that girinimbine significantly reduced the ulcer index and totally safeguarded the mucosa from lesions. The protective effect of girinimbine was complemented through the restoration of the reduced GSH and NP-SH level. This was associated with a reduction of MDA, which was elevated by the administration of ethanol. Pre-treatment of the ethanol induced ulcer with girinimbine reduced the NO concentration in the plasma and elevated PGE2 together with a decreased level of TNF-α and IL-6. Girinimbine had shown suppressing effects on COX-2 enzymes, but not on COX-1. In addition, significantly upregulated HSP70 and downregulated iNOS were observed in girinimbine treated rat tissue at both the transcriptional and translational level. Our results clearly indicated that girinimbine displayed a significant gastro-protection effect, via the capacity to inhibit inflammatory responses and antioxidant potential.

Identification of the Neuroinvasive Pathogen Host Target, LamR, as an Endothelial Receptor for the Treponema pallidum Adhesin Tp0751

Treponema pallidum subsp. pallidum is the causative agent of syphilis, a human-specific sexually transmitted infection that causes a multistage disease with diverse clinical manifestations. Treponema pallidum undergoes rapid vascular dissemination to penetrate tissue, placental, and blood-brain barriers and gain access to distant tissue sites. The rapidity and extent of T. pallidum dissemination are well documented, but the molecular mechanisms have yet to be fully elucidated. One protein that has been shown to play a role in treponemal dissemination is Tp0751, a T. pallidum adhesin that interacts with host components found within the vasculature and mediates bacterial adherence to endothelial cells under shear flow conditions. In this study, we further explore the molecular interactions of Tp0751-mediated adhesion to the vascular endothelium. We demonstrate that recombinant Tp0751 adheres to human endothelial cells of macrovascular and microvascular origin, including a cerebral brain microvascular endothelial cell line. Adhesion assays using recombinant Tp0751 N-terminal truncations reveal that endothelial binding is localized to the lipocalin fold-containing domain of the protein. We also confirm this interaction using live T. pallidum and show that spirochete attachment to endothelial monolayers is disrupted by Tp0751-specific antiserum. Further, we identify the 67-kDa laminin receptor (LamR) as an endothelial receptor for Tp0751 using affinity chromatography, coimmunoprecipitation, and plate-based binding methodologies. Notably, LamR has been identified as a receptor for adhesion of other neurotropic invasive bacterial pathogens to brain endothelial cells, including Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae, suggesting the existence of a common mechanism for extravasation of invasive extracellular bacterial pathogens.IMPORTANCE Syphilis is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum subsp. pallidum. The continued incidence of syphilis demonstrates that screening and treatment strategies are not sufficient to curb this infectious disease, and there is currently no vaccine available. Herein we demonstrate that the T. pallidum adhesin Tp0751 interacts with endothelial cells that line the lumen of human blood vessels through the 67-kDa laminin receptor (LamR). Importantly, LamR is also a receptor for meningitis-causing neuroinvasive bacterial pathogens such as Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae Our findings enhance understanding of the Tp0751 adhesin and present the intriguing possibility that the molecular events of Tp0751-mediated treponemal dissemination may mimic the endothelial interaction strategies of other invasive pathogens.

Challenges of Rapid Plasma Reagin Interpretation in Syphilis Screening in Uganda: Variability in Nontreponemal Results Between Different Laboratories

BACKGROUND

Syphilis is a cause of morbidity and mortality and is of particular concern in pregnancy in low-income countries because of the risks associated with maternal-fetal transmission. Ugandan national guidelines recommend a nontreponemal rapid plasma reagin (RPR) followed by treponemal testing for diagnosis of syphilis. The RPR test confirms a reactive specific treponemal test, or confirms serological "cure" with a 4-fold dilutional decrease; RPR is beset with technical and biological limitations, making accurate diagnosis and appropriate treatment problematic. The aim of this analysis was to compare performance of RPR testing in different laboratories.

METHODS

Stored, freeze-thawed sera from 215 participants were additionally tested for RPR and dilutional titer in 2 different reference laboratories. Discrepant results were tested at a third reference laboratory which served as a tie-breaker. Equivalence in RPR titer was defined as within 2-fold or less. All patients with reactive rapid tests were treated as per Ugandan National Guidelines.

RESULTS

Of 215 sera, 97 (45.1%) were RPR reactive in clinic laboratory A, 81 (37.7%) and 65 (30.2%) were RPR reactive in laboratories B and C, respectively. All reported positive in laboratory C were positive in laboratory B. Discrepant results were tested in laboratory D. χ Test was highly significant (P = <0.001) for difference between each dyad of laboratories (A and B, A and C, and B and C) RPR results. There were significant differences between RPR titers by paired t test and Wilcox rank test (P = <0.001); with up to a 3-fold difference between laboratories. Two one-sided test approach demonstrated nonequivalence. Agreement between laboratories B-D, and C-D: 48 (98.0%) of 49 and 34 (69.4%) of 49, respectively (P = <0.001). Laboratories B and D showed no significant difference and had equivalent RPR titers. Laboratories C and D had different titers (P = <0.001) and were not equivalent.

CONCLUSIONS

We found significant interlaboratory discrepant RPR results. A 3-fold difference in results is likely to be clinically significant and could result in undertreatment or overtreatment. These data demonstrate a key limitation of the RPR test and underline the urgent need for a more reproducible quantitative test than the current RPR for diagnosing and determining cure of syphilis.

Syphilis among Female Sex Workers: Results of Point-of-Care Screening during a Cross-Sectional Behavioral Survey in Burkina Faso, West Africa

Background

Syphilis among female sex workers (FSW) remains a public health concern due to its potential impact on their health and the possibility of transmission to their clients, partners, and children. Recent data on the prevalence of syphilis in the population in West Africa are scarce. The objective of this study was to measure the seroprevalence of syphilis serological markers among female sex workers in Burkina Faso.

Methods

We conducted a cross-sectional survey among FSW between February 2013 and May 2014. Participants were recruited using respondent-driven sampling (RDS) methods in five cities of Burkina Faso (Ouagadougou, Bobo-Dioulasso, Koudougou, Ouahigouya, and Tenkodogo). FSW were enrolled and screened for syphilis using a syphilis serological rapid diagnostic test. Data from all cities were analyzed with Stata version 14.0.

Results

A total of 1045 FSW were screened for syphilis. Participants' mean age was 27.2 ± 0.2 years. The syphilis serological markers were detected in 5.6% (95% CI: 4.4–7.2) of the participants whereas active syphilis was seen in 1.4% (95% CI: 0.9–2.4). RDS weighted prevalence of syphilis serological markers and active syphilis by city were, respectively, estimated to be 0.0% to 11.0% (95% CI: 8.1–14.7) and 0.0% to 2.2% (95% CI: 1.1–4.4). No syphilis markers were found among Ouahigouya FSW. Low education level and high number of clients were factors associated with syphilis markers among the FSW.

Conclusion

The prevalence of syphilis markers was high during this study among FSW. This highlights the need to reinforce the comprehensive preventive measures and treatment of syphilis in this population.

A modeling study of the Danish HIV epidemic in men who have sex with men: travel, pre-exposure prophylaxis and elimination

UNAIDS has identified the Danish HIV epidemic in men who have sex with men (MSM) as a priority for elimination. Incidence is close to the elimination threshold of one new infection per year per 1,000 individuals. However, surveillance data show that HIV strains are being imported into Denmark, mainly due to travel. We use a transmission model to predict (from 2018 to 2030) the impact of pre-exposure prophylaxis (PrEP) on incidence. Our model reflects the current epidemic and diagnosis rates in the Danish MSM community. We conduct a sensitivity analysis based on 20,000 simulations, and assume that PrEP coverage could range from zero to 50% and diagnosis rates increase up to three-fold. We predict that incidence will fall below the elimination threshold, even without the introduction of PrEP, reaching 0.87 (median, 95% Confidence Interval: 0.65-1.23) new infections per 1,000 MSM by 2030. PrEP could reduce incidence to well below the threshold, if it results in a significant increase in diagnosis rates and reduces the number of infections occurring abroad. The Danish Medicine Agency and Danish Health Authority have recommended introducing PrEP. Our study provides strong support for this recommendation, and shows the importance of Danish MSM using PrEP when abroad.

'I'm more aware of my HIV risk than anything else': syndemics of syphilis and HIV among gay men in Winnipeg

Despite decreased rates of HIV infection in Winnipeg, syphilis incidence continues to rise. Communities of men who have sex with men shoulder much of this burden of illness. This qualitative study aimed to better understand the co-evolution of HIV and syphilis in Winnipeg through a series of interviews with gay men. Eighteen individuals were recruited through advertising in sexual health centres and through subsequent snowball sampling. Thematic interpretive analysis and inductive reasoning were used to find individual and shared group meanings. We found that HIV formed the contextual ground on which sexual decision-making was made, with three main themes emerging during interviews: 1) bacterial STI transience being contrasted against HIV permanence; 2) syphilis being 'dirty' versus HIV carrying significant stigma, though being spared the label of uncleanliness; and 3) the role of pleasure and intimacy in sexual health decision-making. Based on these findings, we recommend further exploration to develop more effective strategies around syphilis prevention, in particular with regards to the longer-term illness ramifications and its relationship to HIV transmission.

Comparison of Manual and Fully Automated AIX1000 Rapid Plasma Reagin Assays for Laboratory Diagnosis of Syphilis

The analytical performance of the AIX1000 system, a fully automated and recently FDA-cleared rapid plasma reagin (RPR) system, was evaluated by comparison to a manual RPR test in a traditional syphilis testing algorithm. A total of 1,028 consecutive serum samples submitted for syphilis testing to the University of North Carolina Hospitals Clinical Immunology Laboratory were tested per each manufacturer's instructions. Among those samples, 996 were nonreactive and 20 were reactive using both the ASI RPR card system and the AIX1000 system. Of the 12 discrepant specimens, 11 were AIX1000 reactive and ASI card nonreactive whereas 1 specimen was ASI card reactive and AIX1000 nonreactive. The sensitivity and specificity of the manual ASI card were 76.0% and 99.8%, respectively, while the sensitivity and specificity of the AIX100 were 100.0% and 99.4%, respectively (sensitivity P = 0.03). Among the 20 concordant reactive specimens, 68.4% of the titers agreed within ±1 dilution between methods. Reproducibility testing of the AIX1000 system demonstrated qualitative and semiquantitative (within ±1 dilution) agreement between specimens tested on different days of 96.0% and 76.0%, respectively, and 100.0% agreement between replicates within the same run. One of 24 samples analyzed under other disease conditions was reactive on both the AIX1000 system and the ASI card. Overall, the fully automated AIX1000 system demonstrated significantly enhanced sensitivity and specificity similar to that of the manual ASI RPR card test, making the AIX1000 system suitable for the laboratory diagnosis of syphilis in a clinical laboratory setting.

Comparison of Traditional and Reverse Syphilis Screening Algorithms in Medical Health Checkups

BACKGROUND

The syphilis diagnostic algorithms applied in different countries vary significantly depending on the local syphilis epidemiology and other considerations, including the expected workload, the need for automation in the laboratory and budget factors. This study was performed to investigate the efficacy of traditional and reverse syphilis diagnostic algorithms during general health checkups.

METHODS

In total, 1,000 blood specimens were obtained from 908 men and 92 women during their regular health checkups. Traditional screening and reverse screening were applied to the same specimens using automatic rapid plasma regain (RPR) and Treponema pallidum latex agglutination (TPLA) tests, respectively. Specimens that were reverse algorithm (TPLA) reactive, were subjected to a second treponemal test performed by using the chemiluminescent microparticle immunoassay (CMIA).

RESULTS

Of the 1,000 specimens tested, 68 (6.8%) were reactive by reverse screening (TPLA) compared with 11 (1.1%) by traditional screening (RPR). The traditional algorithm failed to detect 48 specimens [TPLA(+)/RPR(-)/CMIA(+)]. The median TPLA cutoff index (COI) was higher in CMIA-reactive cases than in CMIA-nonreactive cases (90.5 vs 12.5 U).

CONCLUSIONS

The reverse screening algorithm could detect the subjects with possible latent syphilis who were not detected by the traditional algorithm. Those individuals could be provided with opportunities for evaluating syphilis during their health checkups. The COI values of the initial TPLA test may be helpful in excluding false-positive TPLA test results in the reverse algorithm.

High Burden of Human Papillomavirus Infection in Madagascar: Comparison With Other Sexually Transmitted Infections

Background:

In Madagascar, human papillomavirus (HPV), human immunodeficiency virus (HIV), and hepatitis B virus (HBV) infection, as well as syphilis share common risk factors but seem to differ in their prevalence. We measured and compared their prevalence in the country.

Methods:

The data used in this study came from the Saint Damien Health Centre in Ambanja, Madagascar. The tests used for disease detection were the Alere Determine, Virucheck, rapid plasma reagin, and S-DRY self-HPV samples for HIV infection, HBV infection, syphilis, and HPV infection, respectively.

Results:

In men and women, respectively, the prevalence was 0.6% and 0.4% for HIV infection, 2.2% and 2.0% for HBV infection, and 0.6% and 0.3% for syphilis. The HPV infection prevalence was 39.3%.

Conclusions:

Despite common risk factors, the prevalence of HPV infection was high, in contrast to a much lower prevalence of other sexually transmitted infections (STIs) in the same geographical area. Further investigations are required to clarify the status of STIs in the Malagasy population.

Mathematical Analysis of the Transmission Dynamics of HIV Syphilis Co-infection in the Presence of Treatment for Syphilis

The re-emergence of syphilis has become a global public health issue, and more persons are getting infected, especially in developing countries. This has also led to an increase in the incidence of human immunodeficiency virus (HIV) infections as some studies have shown in the recent decade. This paper investigates the synergistic interaction between HIV and syphilis using a mathematical model that assesses the impact of syphilis treatment on the dynamics of syphilis and HIV co-infection in a human population where HIV treatment is not readily available or accessible to HIV-infected individuals. In the absence of HIV, the syphilis-only model undergoes the phenomenon of backward bifurcation when the associated reproduction number ([Formula: see text]) is less than unity, due to susceptibility to syphilis reinfection after recovery from a previous infection. The complete syphilis-HIV co-infection model also undergoes the phenomenon of backward bifurcation when the associated effective reproduction number ([Formula: see text]) is less than unity for the same reason as the syphilis-only model. When susceptibility to syphilis reinfection after treatment is insignificant, the disease-free equilibrium of the syphilis-only model is shown to be globally asymptotically stable whenever the associated reproduction number ([Formula: see text]) is less than unity. Sensitivity and uncertainty analysis show that the top three parameters that drive the syphilis infection (with respect to the associated response function, [Formula: see text]) are the contact rate ([Formula: see text]), modification parameter that accounts for the increased infectiousness of syphilis-infected individuals in the secondary stage of the infection ([Formula: see text]) and treatment rate for syphilis-only infected individuals in the primary stage of the infection ([Formula: see text]). The co-infection model was numerically simulated to investigate the impact of various treatment strategies for primary and secondary syphilis, in both singly and dually infected individuals, on the dynamics of the co-infection of syphilis and HIV. It is observed that if concerted effort is exerted in the treatment of primary and secondary syphilis (in both singly and dually infected individuals), especially with high treatment rates for primary syphilis, this will result in a reduction in the incidence of HIV (and its co-infection with syphilis) in the population.

Mucosal stromal fibroblasts markedly enhance HIV infection of CD4+ T cells

Understanding early events of HIV transmission within mucosal tissues is vital for developing effective prevention strategies. Here, we report that primary stromal fibroblasts isolated from endometrium, cervix, foreskin, male urethra, and intestines significantly increase HIV infection of CD4+ T cells-by up to 37-fold for R5-tropic HIV and 100-fold for X4-tropic HIV-without themselves becoming infected. Fibroblasts were more efficient than dendritic cells at trans-infection and mediate this response in the absence of the DC-SIGN and Siglec-1 receptors. In comparison, mucosal epithelial cells secrete antivirals and inhibit HIV infection. These data suggest that breaches in the epithelium allow external or luminal HIV to escape an antiviral environment to access the infection-favorable environment of the stromal fibroblasts, and suggest that resident fibroblasts have a central, but previously unrecognized, role in HIV acquisition at mucosal sites. Inhibiting fibroblast-mediated enhancement of HIV infection should be considered as a novel prevention strategy.

Incidence of syphilis seroconversion among HIV-infected persons in Asia: results from the TREAT Asia HIV Observational Database

INTRODUCTION

Outbreaks of syphilis have been described among HIV-infected men who have sex with men (MSM) in Western communities, whereas reports in Asian countries are limited. We aimed to characterize the incidence and temporal trends of syphilis among HIV-infected MSM compared with HIV-infected non-MSM in Asian countries.

METHODS

Patients enrolled in the TREAT Asia HIV Observational Database cohort and with a negative non-treponemal test since enrolment were analyzed. Incidence of syphilis seroconversion, defined as a positive non-treponemal test after previously testing negative, was evaluated among patients at sites performing non-treponemal tests at least annually. Factors associated with syphilis seroconversion were investigated at sites doing non-treponemal testing in all new patients and subsequently testing routinely or when patients were suspected of having syphilis.

RESULTS

We included 1010 patients from five sites that performed non-treponemal tests in all new patients; those included had negative non-treponemal test results during enrolment and subsequent follow-ups. Among them, 657 patients were from three sites conducting regular non-treponemal testing. The incidence of syphilis seroconversion was 5.38/100 person-years (PY). Incidence was higher in MSM than non-MSM (7.64/100 PY vs. 2.44/100 PY, p<0.001). Among MSM, the incidence rate ratio (IRR) for every additional year from 2009 was 1.19 (p=0.051). MSM status (IRR 3.48, 95% confidence interval (CI) 1.88-6.47), past syphilis diagnosis (IRR 5.15, 95% CI 3.69-7.17) and younger age (IRR 0.84 for every additional 10 years, 95% CI 0.706-0.997) were significantly associated with syphilis seroconversion.

CONCLUSIONS

We observed a higher incidence of syphilis seroconversion among HIV-infected MSM and a trend to increasing annual incidence. Regular screening for syphilis and targeted interventions to limit transmission are needed in this population.

Risk Factors Associated with Incident Syphilis in a Cohort of High-Risk Men in Peru

BACKGROUND

Syphilis is concentrated among high-risk groups, but the epidemiology of syphilis reinfection is poorly understood. We characterized factors associated with syphilis incidence, including reinfection, in a high-risk cohort in Peru.

METHODS

Participants in the NIMH CPOL trial were assessed at baseline and 2 annual visits with HIV/STI testing and behavioral surveys. Participants diagnosed with syphilis also attended 4- and 9-month visits. All participants underwent syphilis testing with RPR screening and TPPA confirmation. Antibiotic treatment was provided according to CDC guidelines. Reinfection was defined as a 4-fold titer increase or recurrence of seroreactivity after successful treatment with subsequent negative RPR titers. The longitudinal analysis used a Possion generalized estimating equations model with backward selection of variables in the final model (criteria P <0.02).

RESULTS

Of 2,709 participants, 191 (7.05%) were RPR-reactive (median 1:8, range 1:1-1:1024) with TPPA confirmation. There were 119 total cases of incident syphilis, which included both reinfection and first-time incident cases. In the bivariate analysis, the oldest 2 quartiles of age (incidence ratio (IR) 3.84; P <0.001 and IR 8.15; P <0.001) and being MSM/TW (IR 6.48; P <0.001) were associated with higher risk of incident syphilis infection. Of the sexual risk behaviors, older age of sexual debut (IR 12.53; P <0.001), not being in a stable partnership (IR 1.56, P = 0.035), higher number of sex partners (IR 3.01; P <0.001), unprotected sex in the past 3 months (IR 0.56; P = 0.003), HIV infection at baseline (IR 3.98; P <0.001) and incident HIV infection during the study period (IR 6.26; P = 0.003) were all associated with incident syphilis. In the multivariable analysis, older age group (adjusted incidence ratio (aIR) 6.18; P <0.001), men reporting having sex with a man (aIR 4.63; P <0.001), and incident HIV infection (aIR 4.48; P = 0.008) were significantly associated.

CONCLUSIONS

We report a high rate of syphilis reinfection among high-risk men who have evidence of previous syphilis infection. Our findings highlight the close relationship between HIV incidence with both incident syphilis and syphilis reinfection. Further studies on syphilis reinfection are needed to understand patterns of syphilis reinfection and new strategies beyond periodic testing of high-risk individuals based on HIV status are needed.

Vaccine development for syphilis

INTRODUCTION

Syphilis, caused by the spirochete Treponema pallidum subspecies pallidum, continues to be a globally prevalent disease despite remaining susceptible to penicillin treatment. Syphilis vaccine development is a viable preventative approach that will serve to complement public health-oriented syphilis prevention, screening and treatment initiatives to deliver a two-pronged approach to stemming disease spread worldwide. Areas covered: This article provides an overview of the need for development of a syphilis vaccine, summarizes significant information that has been garnered from prior syphilis vaccine studies, discusses the critical aspects of infection that would have to be targeted by a syphilis vaccine, and presents the current understanding within the field of the correlates of protection needed to be achieved through vaccination. Expert commentary: Syphilis vaccine development should be considered a priority by industry, regulatory and funding agencies, and should be appropriately promoted and supported.

Common sexually transmitted infections in adolescents

Adolescents are often at higher risk for acquiring sexually transmitted infections (STIs). Medical providers should be alert for both asymptomatic and symptomatic STIs, and follow appropriate screening guidelines. Moreover, providers need to know how to best administer adolescent-friendly confidential care, treatment, and health education in the primary care setting. This article addresses the most common adolescent STIs and pertinent recommendations for screening, diagnosis, and management of infections, in addition to a brief focused discussion on human immunodeficiency virus and adolescents.

Effectiveness of ART and condom use for prevention of sexual HIV transmission in serodiscordant couples: a systematic review and meta-analysis

Background

Consistent and correct condom use and suppressive antiretroviral therapy for the infected partner are two of the primary strategies recommended for prevention of heterosexual HIV transmission in serodiscordant couples today. The applied effectiveness of treatment as a prevention strategy in China is still under investigation, and much less is known about its effects in the presence of other prevention strategies such as consistent condom use.

Methods

We conducted a systematic search in PubMed and three Chinese language databases to identify relevant articles for the estimation of relative effectiveness of a) consistent condom use and b) ART use by index partners for preventing HIV transmission in serodiscordant couples. We also estimated the prevention effectiveness of ART stratified by condom use level and the prevention effectiveness of consistent condom use stratified by ART use level.

Results

Pooled results from the eleven eligible studies found a pooled HIV seroconversion incidence of 0.92 cases per 100 person years (PY) among HIV-negative spouses whose index partners were taking ART versus 2.45 cases per 100 PY in untreated couples. The IRR comparing seroconversion in couples where the index-partner was on ART versus not on ART was 0.47 (95%CI: 0.43, 0.52), while stratified by condom use, the IRR was 0.33(0.17,0.64). The IRR comparing incidence in couples reporting “consistent condom use” versus those reporting otherwise was 0.02(95%CI:0.01,0.04), after stratified by ART use level, the IRR was 0.01(95%CI: 0.00, 0.06).

Conclusions

ART use by index partners could reduce HIV transmission in serodiscordant couples, and the effectiveness of this prevention strategy could be further increased with consistent condom use.

Prevalence and associated factors for HIV-1 transmitted drug resistance in voluntary clients for counseling and testing in Southern Taiwan

BACKGROUND

According to the World Health Organization, HIV-transmitted drug resistance (TDR) is increasing. We analyzed voluntary counseling test data from a hospital in Southern Taiwan to investigate the TDR pattern in Southern Taiwan, the potential relationship between sexual behavior and HIV transmission, and HIV drug-resistant strain transmission.

METHODS

Genotypic resistance assays were performed on treatment-naïve HIV patients recruited from voluntary counseling testing (VCT) in Southern Taiwan from 2007 to 2011. Drug resistance-associated mutations were interpreted with Stanford University HIV Drug Resistance Database HIVdb program. Socio-demographics and sexual activity were recorded from the VCT questionnaire. Logistic regression analysis was used to analyze the risk factors for TDR, and a phylogenetic tree was constructed to elucidate the pattern of HIV drug-resistant strains.

RESULTS

Among the 161 treatment-naïve HIV-infected patients, most were men who reported having sex with men. The overall TDR rate was 10.6%. Patients with a history of sexually transmitted diseases had a 7.8-fold higher risk of becoming infected with genotypic resistant strains.

CONCLUSION

In Southern Taiwan, the HIV TDR rate was 10.6% among those receiving VCT. Our findings suggest that sexual behavior may play an important role in HIV drug-resistant strain transmission.

Consistency Between Treponema pallidum Particle Agglutination Assay and Architect Chemiluminescent Microparticle Immunoassay and Characterization of Inconsistent Samples

BACKGROUND

Treponema pallidum particle agglutination assay (TPPA) has been shown to be highly sensitive and specific at detecting treponemal antibodies and is still used as a confirmatory method in many laboratories, in China. In clinical practice, we found that a significant number of TPPA-negative sera were identified when TPPA was used as a confirmatory assay of Architect chemiluminescent microparticle immunoassay (CMIA) screening-reactive sera.

AIMS

To investigate the consistency between Architect CMIA and TPPA, and analyzed the characterization of TPPA-negative sera following Screening by Architect CMIA.

METHODS

According to the laboratory syphilis confirmatory testing protocol, a total of 4870 sera were initially tested by Architect CMIA and ELISA, and then the samples which shown positive results were tested by TPPA and rapid plasma reagin tests (RPR). Further analysis using Euroimmun dot-immunoblot (dot-IBT) assay was performed to the CMIA positive and TPPA negative samples.

RESULTS

In our cohort, we found that the positive rate of CMIA was 3.1% (149/4870). One hundred and twelve of 112 (75.2%) CMIA-positive sera were TPPA reactive, while 37 (24.8%) sera which were reactive in CMIA were nonreactive by TPPA. Dot-IBT testing was performed on these 37 sera: 8 (21.6%) were dot-IBT positive, 11 (29.7%) were indeterminate and 18 (48.6%) negative.

DISCUSSION

In this study, we observed that 18 CMIA-positive sera were false positives confirmed by dot-IBT. But, given the relatively high levels of early syphilis, we consider a small increase in the number of confirmatory tests is worthwhile if we can increase the detection of primary syphilis by 20%. We also found that significant numbers (8/37) of CMIA-positive and TPPA-negative sera were shown by further dot-IBT testing to be positive. The reason why certain sera are negative by TPPA but reactive by CMIA and other syphilis confirmatory assays is not clear, and these initial findings should be further explored.

CONCLUSION

The Architect CMIA is a highly sensitive screening assay for detecting syphilis but it is significantly less specific. Further analysis by TPPA is recommended to confirm the results. We would highlight the fact that in repeatedly screened populations discrepancies between treponemal CMIA and TPPA results are quite prevalent. This seems to be a function of very low levels of syphilis-specific antibodies. Confirmation by immunoblot assay may be useful.

HIV infection and risk factors among the armed forces personnel stationed in Kinshasa, Democratic Republic of Congo

Despite recent declines in HIV incidence, sub-Saharan Africa remains the most heavily affected region in the global HIV/AIDS epidemic. Estimates of HIV prevalence in African military personnel are scarce and inconsistent. We conducted a serosurvey between June and September 2007 among 4043 Armed Forces personnel of the Democratic Republic of Congo (FARDC) stationed in Kinshasa, Democratic Republic of Congo (DRC) to determine the prevalence of HIV and syphilis infections and describe associated risk behaviours. Participants provided blood for HIV and syphilis testing and responded to a demographic and risk factor questionnaire. The prevalence of HIV was 3.8% and the prevalence of syphilis was 11.9%. Women were more likely than men to be HIV positive, (7.5% vs. 3.6% respectively, aOR: 1.66, 95% C.I: 1.21-2.28, p < 0.05). Factors significantly associated with HIV infection included gender and self-reported genital ulcers in the 12 months before date of enrollment. The prevalence of HIV in the military appears to be higher than the general population in DRC (3.8% vs. 1.3%, respectively), with women at increased risk of infection.

Intravaginal rings as delivery systems for microbicides and multipurpose prevention technologies

There is a renewed interest in delivering pharmaceutical products via intravaginal rings (IVRs). IVRs are flexible torus-shaped drug delivery systems that can be easily inserted and removed by the woman and that provide both sustained and controlled drug release, lasting for several weeks to several months. In terms of women's health care products, it has been established that IVRs effectively deliver contraceptive steroids and steroids for the treatment of postmenopausal vaginal atrophy. A novel application for IVRs is the delivery of antiretroviral drugs for the prevention of human immunodeficiency virus (HIV) genital infection. Microbicides are antiviral drugs delivered topically for HIV prevention. Recent reviews of microbicide IVRs have focused on technologies in development and optimizing ring design. IVRs have several advantages, including the ability to deliver sustained drug doses for long periods of time while bypassing first pass metabolism in the gut. IVRs are discreet, woman-controlled, and do not require a trained provider for placement or fitting. Previous data support that women and their male sexual partners find IVRs highly acceptable. Multipurpose prevention technology (MPT) products provide protection against unintended/mistimed pregnancy and reproductive tract infections, including HIV. Several MPT IVRs are currently in development. Early clinical testing of new microbicide and MPT IVRs will require a focus on safety, pharmacokinetics and pharmacodynamics. Specifically, IVRs will have to deliver tissue concentrations of drugs that are pharmacodynamically active, do not cause mucosal alterations or inflammation, and do not change the resident microbiota. The emergence of resistance to antiretrovirals will need to be investigated. IVRs should not disrupt intercourse or have high rates of expulsion. Herein, we reviewed the microbicide and MPT IVRs currently in development, with a focus on the clinical aspects of IVR assessment and the challenges facing microbicide and MPT IVR product development, clinical testing, and implementation. The information in this review was drawn from PubMed searches and a recent microbicide/MPT product development workshop organized by CONRAD.

Mutational analysis of hemoglobin binding and heme utilization by a bacterial hemoglobin receptor

Iron is an essential nutrient for most living organisms. To acquire iron from their environment, Gram-negative bacteria use TonB-dependent transporters that bind host proteins at the bacterial surface and transport iron or heme to the periplasm via the Ton machinery. TonB-dependent transporters are barrel-shaped outer membrane proteins with 22 transmembrane domains, 11 surface-exposed loops, and a plug domain that occludes the pore. To identify key residues of TonB-dependent transporters involved in hemoglobin binding and heme transport and thereby locate putative protective epitopes, the hemoglobin receptor of Haemophilus ducreyi HgbA was used as a model of iron/heme acquisition from hemoglobin. Although all extracellular loops of HgbA are required by H. ducreyi to use hemoglobin as a source of iron/heme, we previously demonstrated that hemoglobin binding by HgbA only involves loops 5 and 7. Using deletion, substitution, and site-directed mutagenesis, we were able to differentiate hemoglobin binding and heme acquisition by HgbA. Deletion or substitution of the GYEAYNRQWWA region of loop 5 and alanine replacement of selected histidines affected hemoglobin binding by HgbA. Conversely, mutation of the phenylalanine in the loop 7 FRAP domain or substitution of the NRQWWA motif of loop 5 significantly abrogated utilization of heme from hemoglobin. Our findings show that hemoglobin binding and heme utilization by a bacterial hemoglobin receptor involve specific motifs of HgbA.

Poly (4-styrenesulfonic acid-co-maleic acid) is an entry inhibitor against both HIV-1 and HSV infections - potential as a dual functional microbicide

Genital herpes is one of the most prevalent sexually transmitted diseases (STD) caused by herpes simplex viruses type 1 and 2 (HSV-1 and -2). HSV is considered as a major risk factor in human immunodeficiency virus type-1 (HIV-1) infection and rapid progression to acquired immunodeficiency syndrome (AIDS). Here, we reported the finding of a polymer of styrenesulfonic acid and maleic acid (PSM) which exhibited antiviral activity with low cytotoxicity. PSM exhibited in vitro inhibitory activity against HIV-1 pseudovirus and HSV-1 and -2. In vivo efficacy of PSM against HSV-2 (G) was also investigated. We found that both 1% and 5% PSM gels protected mice from HSV-2 vaginal infection and disease progression significantly. Mechanistic analysis demonstrated that PSM was likely an entry inhibitor that disrupted viral attachment to the target cells. In particular, PSM disrupted gp120 binding to CD4 by interacting with the gp120 V3-loop and the CD4-binding site. The in vitro cytotoxicity studies showed that PSM did not stimulate NF-κB activation and up-regulation of proinflammatory cytokine IL-1β and IL-8 in vaginal epithelial cells. In addition, PSM also showed low adverse effect on the growth of vaginal Lactobacillus strains. PSM is, therefore, a novel viral entry inhibitor and a potential microbicide candidate against both HIV-1 and HSV.

Syphilis Infection during pregnancy: fetal risks and clinical management

Congenital syphilis is still a cause of perinatal morbidity and mortality. Untreated maternal infection leads to adverse pregnancy outcomes, including early fetal loss, stillbirth, prematurity, low birth weight, neonatal and infant death, and congenital disease among newborns. Clinical manifestations of congenital syphilis are influenced by gestational age, stage of maternal syphilis, maternal treatment, and immunological response of the fetus. It has been traditionally classified in early congenital syphilis and late congenital syphilis. Diagnosis of maternal infection is based on clinical findings, serological tests, and direct identification of treponemes in clinical specimens. Adequate treatment of maternal infection is effective for preventing maternal transmission to the fetus and for treating fetal infection. Prenatal diagnosis of congenital syphilis includes noninvasive and invasive diagnosis. Serological screening during pregnancy and during preconception period should be performed to reduce the incidence of congenital syphilis.

Footprint of positive selection in Treponema pallidum subsp. pallidum genome sequences suggests adaptive microevolution of the syphilis pathogen

In the rabbit model of syphilis, infection phenotypes associated with the Nichols and Chicago strains of Treponema pallidum (T. pallidum), though similar, are not identical. Between these strains, significant differences are found in expression of, and antibody responses to some candidate virulence factors, suggesting the existence of functional genetic differences between isolates. The Chicago strain genome was therefore sequenced and compared to the Nichols genome, available since 1998. Initial comparative analysis suggested the presence of 44 single nucleotide polymorphisms (SNPs), 103 small (≤3 nucleotides) indels, and 1 large (1204 bp) insertion in the Chicago genome with respect to the Nichols genome. To confirm the above findings, Sanger sequencing was performed on most loci carrying differences using DNA from Chicago and the Nichols strain used in the original T. pallidum genome project. A majority of the previously identified differences were found to be due to errors in the published Nichols genome, while the accuracy of the Chicago genome was confirmed. However, 20 SNPs were confirmed between the two genomes, and 16 (80.0%) were found in coding regions, with all being of non-synonymous nature, strongly indicating action of positive selection. Sequencing of 16 genomic loci harboring SNPs in 12 additional T. pallidum strains, (SS14, Bal 3, Bal 7, Bal 9, Sea 81-3, Sea 81-8, Sea 86-1, Sea 87-1, Mexico A, UW231B, UW236B, and UW249C), was used to identify "Chicago-" or "Nichols -specific" differences. All but one of the 16 SNPs were "Nichols-specific", with Chicago having identical sequences at these positions to almost all of the additional strains examined. These mutations could reflect differential adaptation of the Nichols strain to the rabbit host or pathoadaptive mutations acquired during human infection. Our findings indicate that SNPs among T. pallidum strains emerge under positive selection and, therefore, are likely to be functional in nature.

Liver involvement in HIV-infected patients diagnosed with syphilis

PURPOSE

Liver involvement in syphilis has been studied in cohorts of human immunodeficiency virus (HIV)-negative individuals despite the scarcity of data on such HIV-infected patients. Th aim of this study was to assess hepatic involvement of HIV-infected patients diagnosed with syphilis.

METHODS

Patients with syphilis and liver involvement, including all stages of syphilis, were systematically identified in our HIV cohort between 2004 and 2008.

RESULTS

Of the 1,599 HIV-infected patients identified during the study period, 100 were diagnosed with acute syphilis, all of whom were male. Of these 100 patients, 84% were men who have sex with men. Laboratory parameters of liver involvement were present in 19 of the 100 HIV-infected patients with syphilis; these resolved after successful antibiotic treatment. Among these 19 patients, six were diagnosed to be in the latent stage, with elevated liver enzymes and parameters of inflammation representing the only distinctive feature.

CONCLUSIONS

Based on our results, syphilis should be included in the differential diagnosis of increased liver enzymes in HIV-infected patients.

The molecular diagnosis of sexually transmitted genital ulcer disease

Highly sensitive and specific nucleic acid amplification tests (NAATs) have emerged as the gold standard diagnostic tests for many infectious diseases. Real-time PCR has further refined the technology of nucleic acid amplification with detection in a closed system and enabled multiplexing to simultaneously detect multiple pathogens. It is a versatile, fast, and high-throughput system for pathogen detection that has reduced the risk of PCR contamination, eliminated post-PCR manipulations, and improved the cost-effectiveness of testing. In addition, real-time PCR can be applied to self-collected noninvasive specimens. Here, we describe an in-house developed TaqMan-based real-time multiplex PCR (M-PCR) assay for the diagnosis of sexually transmitted genital ulcer disease (GUD) and discuss briefly on issues associated with validation of assay performance.

Immune modulation during latent herpesvirus infection

Nearly all human beings, by the time they reach adolescence, are infected with multiple herpesviruses. At any given time, this family of viruses accounts for 35-40 billion human infections worldwide, making herpesviruses among the most prevalent pathogens known to exist. Compared to most other viruses, herpesviruses are also unique in that infection lasts the life of the host. Remarkably, despite their prevalence and persistence, little is known about how these viruses interact with their hosts, especially during the clinically asymptomatic phase of infection referred to as latency. This review explores data in human and animal systems that reveal the ability of latent herpesviruses to modulate the immune response to self and environmental antigens. From the perspective of the host, there are both potentially detrimental and surprisingly beneficial effects of this lifelong interaction. The realization that latent herpesvirus infection modulates immune responses in asymptomatic hosts forces us to reconsider what constitutes a 'normal' immune system in a healthy individual.

Syphilis: using modern approaches to understand an old disease

Syphilis is a fascinating and perplexing infection, with protean clinical manifestations and both diagnostic and management ambiguities. Treponema pallidum subsp. pallidum, the agent of syphilis, is challenging to study in part because it cannot be cultured or genetically manipulated. Here, we review recent progress in the application of modern molecular techniques to understanding the biological basis of this multistage disease and to the development of new tools for diagnosis, for predicting efficacy of treatment with alternative antibiotics, and for studying the transmission of infection through population networks.

Screening for syphilis with the treponemal immunoassay: analysis of discordant serology results and implications for clinical management

BACKGROUND

Screening for syphilis with treponemal chemiluminescence immunoassays (CIA) identifies patients with discordant serology who are not identified with traditional screening methods (eg, CIA-positive, rapid plasma regain (RPR)-negative). We sought to describe the clinical characteristics and management of patients with discordant syphilis serology.

METHODS

From August 2007-October 2007, patients with CIA-positive, RPR-negative serology were tested with the Treponema pallidum particle agglutination assay (TP-PA) at Kaiser Permanente Northern California. Clinical and demographic characteristics, prior syphilis history and CIA index values were compared for CIA-positive, RPR-negative patients according to TP-PA status.

RESULTS

Of 21,623 assays, 439 (2%) were CIA-positive and 255/439 (58%) were RPR-negative; subsequently, 184 (72%) were TP-PA-positive and 71 (28%) were TP-PA--negative. TP-PA--positive patients were more likely to be male, HIV-positive, homosexual, previously treated for syphilis (57% versus 9%), with higher median CIA index values (9.8 versus 1.6) (all P < .0001). After repeat testing, 7/31 (23%) CIA-positive, RPR-negative, TP-PA--negative patients seroreverted to CIA-negative.

CONCLUSIONS

TP-PA results in conjunction with clinical/behavioral assessment helped guide the management of patients with CIA-positive, RPR-negative serology. TP-PA-positive patients were both highly likely to have prior syphilis and major epidemiologic risk factors for syphilis. CIA-positive, RPR-negative, TP-PA-negative serology may represent a false-positive CIA in low-prevalence populations.

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.

Immune responses to HIV in the female reproductive tract, immunologic parallels with the gastrointestinal tract, and research implications

The female reproductive tract is a major site of mucosa-associated lymphoid tissue and susceptibility to HIV infection, yet the tissue site(s) of infection and the impact of HIV infection on this important mucosal tissue remain poorly understood. CD4(+) T cells and other cell types expressing the major coreceptors for HIV, CCR5, and CXCR4 are abundant in both the lower reproductive tract (endocervix and vagina) and the upper tract (endocervix and uterus) and are highly susceptible to infection. Antiviral defenses in the female reproductive tract are mediated by a variety of soluble factors and by mucosal effector cells that differ phenotypically from their counterparts in blood. The immunologic characteristics of the female reproductive tract parallel those of the gut, where major HIV-related immunologic injury occurs. The susceptibility of the female reproductive tract to HIV infection and immunopathogenesis suggests important new avenues for further research.

Emerging issues in management of sexually transmitted diseases in HIV infection

Sexually transmitted diseases (STDs) occur often among sexually active persons with HIV infection. Incident STDs may complicate the course of HIV infection and potentiate HIV transmission in the coinfected individual by mucosal disruption and an increase in HIV concentration in ulcers and involved mucous membranes. Conducting ongoing periodic sexual risk assessments in HIV-positive patients in routine medical care is critical to identifying asymptomatic infections. HIV clinicians should be familiar with updated recommendations for screening, diagnosis, and treatment of bacterial and viral STDs, including those specific to HIV infection. This article addresses emerging issues in the management of STDs in HIV-infected persons and summarizes the latest evidence that can be applied to clinical decision-making in this population.

Complete genome sequence and annotation of the Treponema pallidum subsp. pallidum Chicago strain

In syphilis research, the Nichols strain of Treponema pallidum, isolated in 1912, has been the most widely studied. Recently, important differences among T. pallidum strains emerged; therefore, we sequenced and annotated the Chicago strain genome to facilitate and encourage the use of this strain in studying the pathogenesis of syphilis.

Experience of meningovascular syphilis in human immunodeficiency virus infected patient

Since the start of the antibiotic era, syphilis has become rare. However, in recent times, it has tended to be prevalent concomitantly with human immunodeficiency virus (HIV) infection and coinfection in North America and Europe. Now, such cases are expected to increase in elsewhere including Korea. A 40-year-old male patient visited hospital complaining of a headache for about one month. Brain computed tomography and magnetic resonance imaging, showed leptomeninged enhancing mass with edema an right porisylvian region, which was suspected to be glioma. Patient underwent a blood test and was diagnosed with syphilis and acquired immune deficiency syndrome. Partial cortical and subcortical resection were performed after small craniotomy. The dura was thick, adhered to the brain cortex, and was accompanied by hyperemic change of the cortex. The pathologic diagnosis was meningovascular syphilis (MS) in HIV infection. After the operation, the patient was treated with aqueous penicillin G. Thereafter, he had no neurological deficit except intermittent headache. At first, this case was suspected to be glioma, but it was eventually diagnosed as MS in HIV coinfection. At this point the case was judged to be worth reporting.

The potential role of biomarkers in HIV preventive vaccine trials

BACKGROUND

Successful conduct of HIV vaccine efficacy trials entails identification and enrollment of at-risk populations, assessment of appropriate end points as measures of vaccine efficacy for prevention of HIV acquisition, and amelioration of disease course among infected vaccinees, as well as identification of potential confounders or effect modifiers. Although not invariably useful and bringing their own cost in terms of measurement and validation, a variety of biomarkers may aid at each stage of trial conduct.

METHODS

A review of selected articles, chosen based on quality, relevance of the biomarker to HIV vaccine trials, and availability of the publication, was conducted. The authors also drew experience from current trials and other planned or ongoing trials.

CONCLUSIONS

Biomarkers are available to assess HIV incidence in potential study populations, but care is needed in interpreting results of these assays. During trial conduct, sexually transmitted infections such as herpes simplex virus type 2 may act as effect modifiers on primary and secondary end points, including HIV incidence and set point viral load. The utility of sexually transmitted infection biomarkers will likely depend heavily on local epidemiology at clinical trial sites. Analyses from recent large HIV vaccine efficacy trials point to the complexities in interpreting trial results and underscore the potential utility of biomarkers in evaluating confounding and effect modification.

Laboratory diagnosis of syphilis with automated immunoassays

The serological detection of specific antibodies to Treponema pallidum is of particular importance in the diagnosis of syphilis. The purpose of this study was to evaluate diagnostic performances of automated immunoassays in comparison with T. pallidum hemagglutination test (TPHA) and Western Blot (WB). The retrospective study was performed with different panels of sera: 244 clinical and serological characterized syphilitic sera and 203 potentially interfering samples. All the sera were tested by Enzygnost Syphilis, ARCHITECT Syphilis TP, TPHA, and homemade WB. The diagnostic performances of the two assays were very similar: both Enzygnost Syphilis and ARCHITECT Syphilis TP performed with a sensitivity of 99.2%, whereas the specificity was 98.5 and 98.4%, respectively. Considering the suitability for automation, both immunoassays may represent a good choice as a screening test. However, the use of a confirmatory test, such as TPHA or WB, remains a must in order to avoid false-positive results.

Injecting drug users and the Human Immunodeficiency Virus: what do we know?

This article examines the results of 10 years of research on the relationship between injecting drug use and the Human Immunodeficiency Virus (HIV). The two main transmission modes of HIV among injecting drug users (IDU)-parenteral drug use and sexual behaviour-are examined in detail, as well as the efficacy of attempted interventions to reduce the spread of HIV among this population.

Syphilis in drug users in low and middle income countries

BACKGROUND

Genital ulcer disease (GUD), including syphilis, is an important cause of morbidity in low and middle income (LMI) countries and syphilis transmission is associated with HIV transmission.

METHODS

We conducted a literature review to evaluate syphilis infection among drug users in LMI countries for the period 1995-2007. Countries were categorized using the World Bank Atlas method [The World Bank. (2007). Data and statistics: Country groups. Retrieved online October 18, 2007 at http://go.worldbank.org/D7SN0B8YU0] according to 2006 gross national income per capita.

RESULTS

Thirty-two studies were included (N=13,848 subjects), mostly from Southeast Asia with some from Latin America, Eastern Europe, Central and East Asia, North Africa and the Middle East but none from regions such as Sub-Saharan Africa. The median prevalence of overall lifetime syphilis (N=32 studies) was 11.1% (interquartile range: 6.3-15.3%) and of HIV (N=31 studies) was 1.1% (interquartile range: 0.22-5.50%). There was a modest relation (r=0.27) between HIV and syphilis prevalence. Median syphilis prevalence by gender was 4.0% (interquartile range: 3.4-6.6%) among males (N=11 studies) and 19.9% (interquartile range: 11.4-36.0%) among females (N=6 studies). There was a strong relation (r=0.68) between syphilis prevalence and female gender that may be related to female sex work.

CONCLUSION

Drug users in LMI countries have a high prevalence of syphilis but data are limited and, in some regions, entirely lacking. Further data are needed, including studies targeting the risks of women. Interventions to promote safer sex, testing, counselling and education, as well as health care worker awareness, should be integrated in harm reduction programs and health care settings to prevent new syphilis infections and reduce HIV transmission among drug users and their partners in LMI countries.