Classification of incidence and prevalence of certain sexually transmitted infections by world regions

20 years of herpes simplex virus type 2 (HSV-2) research in low-income and middle-income countries: systematic evaluation of progress made in addressing WHO priorities for research in HSV-2/HIV interactions, HSV-2 control and mathematical modelling

INTRODUCTION

Reviewing and updating research priorities is essential to assess progress and to ensure optimal allocation of financial and human resources in research. In 2001, WHO held a research priority setting workshop for herpes simplex virus type 2 (HSV-2) research in low-income and middle-income countries (LMICs). This study aimed to describe progress between 2000 and 2020 in three of the five key research priority areas outlined in the workshop: HSV-2/HIV interactions, HSV-2 control measures and HSV-2 mathematical modelling. The remaining priorities are addressed in a companion paper.

METHOD

A systematic literature search of MEDLINE, CINAHL, Global Health and Cochrane databases was carried out. Relevant primary research studies based in LMICs, written in English and published on 2000-2020 were included. Papers were screened by two independent reviewers, and suitable variables were selected for manual extraction from study texts. Data were organised into an Excel spreadsheet and analysed using IBM SPSS.

RESULTS

In total, 3214 discrete papers were identified, of which 180 were eligible for inclusion (HSV-2/HIV interactions, 98; control measures, 58; mathematical modelling, 24). Most studies were conducted in East Africa. The majority of the 2001 WHO HSV-2 research priorities were addressed at least in part. Overall, despite several studies describing a strong relationship between HSV-2 and the acquisition and transmission of HIV, HSV-2 control repeatedly demonstrated little effect on HIV shedding or transmission. Further, although mathematical modelling predicted that vaccines could significantly impact HSV-2 indicators, HSV-2 vaccine studies were few. Studies of antiviral resistance were also few.

CONCLUSION

Since 2000, LMIC HSV-2 research addressing its control, HIV interactions and mathematical modelling has largely addressed the priorities set in the 2001 WHO HSV-2 workshop. However, key knowledge gaps remain in vaccine research, antiviral cost-effectiveness, antiviral resistance and specific geographical areas.

The global burden of sexually transmitted infections

Understanding the global burden of sexually transmitted infections (STIs) is fundamental to being able to address and control these infections and the health harms they cause. The World Health Organization has renewed its global health sector strategy for the prevention and control of STIs. Reducing STIs remains an integral part of HIV prevention and of sexual and reproductive health programs. Data to measure and describe the global burden continue to improve, with systematic reviews and modeling providing global and regional data for the major STIs. Although substantial gaps remain, as many countries have limited data, the measures available demonstrate the scale of the problem for the main curable STIs, gonorrhea, chlamydia, syphilis, and trichomoniasis; the most common viral STIs, human papillomavirus and genital herpes; the interrelation between STIs and HIV; and the substantially unequal burden of these infections globally and among key populations. Regional and global trends in these infections are affected by population changes; the impact and availability of interventions, such as vaccination; changing behaviors that alter the dynamics of STI transmission; and the role of international travel in promulgating STIs in an increasingly interconnected world.

The association between non-viral sexually transmitted infections and pregnancy outcome in Latin America and the Caribbean: A systematic review

Introduction

Non-viral sexually transmitted infections are known to be associated with adverse pregnancy outcomes. For these pathogens, standard antenatal screening is not broadly performed in Latin America and the Caribbean. The aim of this study was to comprehensively review the association of non-viral sexually transmitted infections and neonatal outcomes among pregnant women in the region.

Methods

Four databases (PubMed, Embase, SciELO and LILACS) were examined to identify eligible studies published up to September 2022. English or Spanish cross-sectional, case-control and cohort studies assessing the association of non-viral sexually transmitted infections and adverse pregnancy outcomes were evaluated. Articles were firstly screened by means of title and abstract. Potential articles were fully read and assessed for inclusion according to the eligibility criteria. Snowballing search was performed by screening of bibliographies of the chosen potentially relevant papers. Risk of bias within studies was assessed using the Joanna Briggs Institute reviewer's manual.

Results

A selection of 10 out of 9772 search records from five Latin America and the Caribbean countries were included. Six studies associated Treponema pallidum infection with preterm birth (1/6), history of previous spontaneous abortion (2/6), fetal and infant death (1/6), low birth weight (1/6) and funisitis of the umbilical cord (1/6). Three studies associated Chlamydia trachomatis infection with preterm birth (2/3), ectopic pregnancy (1/3) and respiratory symptoms on the newborn (1/3). One study associated Mycoplasma genitalium infection with preterm birth.

Conclusion

This review provides evidence on the association of non-viral sexually transmitted infections with adverse pregnancy outcomes. Further investigation is needed to establish more associations between non-viral sexually transmitted infections and pregnancy outcome, especially for Mycoplasma genitalium, Trichomonas vaginalis and Neisseria gonorrhoeae. Overall, this review calls for more research for public health interventions to promote screening of non-viral sexually transmitted infections during pregnancy, among high-risk population groups of pregnant women living in the region.

Assessing knowledge, attitudes, and practices toward sexually transmitted infections among Baghdad undergraduate students for research-guided sexual health education

Background

Sexually transmitted infections are common and tend to cause a lot of public misconceptions. This study was conducted to identify knowledge gaps and negative attitudes toward sexually transmitted infections and infected individuals among undergraduate students and give recommendations accordingly for the development of more objective research-guided health campaigns and school sex education programs.

Method

A cross-sectional study was conducted between May 17, 2022 and June 2, 2022 using a self-administrated questionnaire containing 84 items related to sexually transmitted infections distributed online to Baghdad-based university students.

Result

The sample consisted of 823 respondents; 332 men and 491 women. Overall knowledge was moderate to high, with 628 individuals (76.3%) answering more than half the questions correctly. There was no difference according to gender or previous sexual experience, but knowledge increased by an average of 2.73 points (p < 0.001) when a participant knew a previously infected individual. Less than half identified systemic symptoms of STIs, and their knowledge of other HIV items was also poor. Most respondents (85.5%) agreed to the need for sex education during middle or high school and cited traditional barriers as the most critical barrier (64.8%); in comparison, those who did not agree on its need cited the sensitivity of the subject (40.3%) or religious barriers (20.2%) as more important.

Conclusion

Specific knowledge gaps exist for HIV and non-HIV sexually transmitted infections; these should be addressed during sex education, focusing on specific high-risk groups. Negative attitudes and stigmatizing behavior should be addressed as well by increasing focused STI knowledge.

A systematic review of the prevalence of selected sexually transmitted infections in young people in Latin America

Objective

To estimate the burden of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Treponema pallidum (TP), and human papillomavirus (HPV) infections among people aged 10 to 25 in Latin America and the Caribbean.

Methods

The MEDLINE, EMBASE, and LILACS databases were searched, as well as documents from regional organizations or national health Institutions. Population-based studies that reported prevalence or incidence of CT, NG, TP, and HPV detected through confirmatory tests in adolescents and young people were included. Two reviewers independently selected studies and extracted data. The quality of studies was assessed using the Newcastle-Ottawa Scale. Pooled estimators were calculated in cases where heterogeneity was <70%; when not feasible, prevalence ranges were reported.

Results

Out of a total of 3 583 references, 15 prevalence studies complied with the inclusion criteria. Due to substantial heterogeneity (>70%), it was not possible to pool frequency estimators. Among the general population, the prevalence of CT infection ranged between 2.1% and 30.1% (9 studies, 5 670 participants); for NG, prevalence ranged between 0% and 2.9% (8 studies, 5 855 participants); for TP, prevalence varied between 0% and 0.7% (3 studies, 11 208 participants), and for HPV infection, prevalence ranged between 25.1% and 55.6% (8 studies, 3 831 participants).

Conclusions

Reliable, population-based data on sexually transmitted infections (STIs) in adolescents and youth in Latin America and the Caribbean are limited. Additional studies are needed to better understand the burden of STIs in this population. However, given the substantial prevalence of STIs detected, countries need public health policies for prevention, early diagnosis, and treatment of STIs in young people.

Evaluating the diagnosis and treatment of Chlamydia trachomatis and Neisseria gonorrhoeae in pregnant women to prevent adverse neonatal consequences in Gaborone, Botswana: protocol for the Maduo study

BACKGROUND

Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are extremely common sexually transmitted infections (STIs) that are associated with adverse birth and neonatal outcomes, and the risk of vertical transmission of CT and NG during delivery is high. The majority of CT and NG infections are asymptomatic and missed by the standard of care in most countries (treatment based on symptoms). Thus, it is likely that missed maternal CT and NG infections contribute to preventable adverse health outcomes among women and children globally. This study aims to assess the effectiveness of CT and NG testing for asymptomatic pregnant women to prevent adverse neonatal outcomes, understand the inflammatory response linking CT and NG infections to adverse neonatal outcomes, and conduct an economic analysis of the CT and NG testing intervention.

METHODS

The Maduo ("results" in Setswana) is a prospective, cluster-controlled trial in Gaborone, Botswana to compare a near point-of-care CT and NG testing and treatment intervention implemented in "study clinics" with standard antenatal care (World Health Organization-endorsed "syndromic management" strategy based on signs and symptoms without laboratory confirmation) implemented in "standard of care clinics" among asymptomatic pregnant women. The primary outcome is vertical transmission of CT/NG infection. Secondary outcomes include preterm birth (delivery < 37 completed weeks of gestation) and/or low birth weight (< 2500 g). The trial will also evaluate immunological and inflammatory markers of adverse neonatal outcomes, as well as the costs and cost-effectiveness of the intervention compared with standard care.

DISCUSSION

The Maduo study will improve our understanding of the effectiveness and cost-effectiveness of CT and NG testing among asymptomatic pregnant women. It will also increase knowledge about the CT/NG-related immune responses that might drive adverse neonatal outcomes. Further, results from this study could encourage expansion of STI testing during antenatal care in low resource settings and improve maternal and neonatal health globally.

TRIAL REGISTRATION

This trial is registered with ClinicalTrials.gov (Identifier NCT04955717, First posted: July 9, 2021)).

Information-seeking behavior on sexually transmitted infections and its associated factors among university students in Ethiopia: a cross-sectional study

Background

Sexually Transmitted Infections (STIs) are infections commonly spread through sexual contact and transmitted by bacteria, viruses, or parasites. In today’s world, STI-related information-seeking behavior is often vital for the advancement of knowledge, behavioral changes, health decisions, and the sharing of sexual health information among youths. However, paucity of evidence on information-seeking behavior among students in higher education institutions. This study aimed to assess STI-related information-seeking behavior and its associated factors among students at the University of Gondar.

Methods

An institution-based cross-sectional quantitative study was conducted among students at the University of Gondar from January 15 to February 15, 2021. A total of 832 participants were selected using a stratified two-stage sampling method. A structured self-administered questionnaire was used to collect the required data. STI information-seeking behavior questionnaire was adapted from health information national survey tool (HINTS). Descriptive statistics, bi-variable, and multivariable logistic regression analyses were applied using SPSS version 26.

Result

The proportion of STI related information-seeking among university students was 462 (55.5%) with 95% CI (52.3, 58.9). About 263 (56.9%) of students preferred internet as a primary source for STI related information. Year of study being 4th (AOR = 4.77, 95% CI = 2.75, 8.29) and 5th year (AOR = 5.45, 95% CI = 2.48, 12.01), field of study being health (AOR = 2.19, 95% CI = 1.16, 4.11), sexual experiences (AOR = 2.33, 95% CI = 1.56, 3.48), ever had STI symptoms (AOR = 4.19, 95% CI = 2.14, 8.18), perceived susceptibility (AOR = 5.05, 95% CI = 3.29, 7.75), and perceived severity (AOR = 2.16,95% CI = 1.45, 3.22) were significant factors for good STI information-seeking.

Conclusion

the proportion of STI information-seeking among university students was low. Students' STI information-seeking behavior could be improved by increasing digital literacy and enhancing computer and internet access across the campus.

Sexually Transmitted Infections (STIs) are infections commonly spread through sexual contact and transmitted by bacteria, viruses, or parasites and are the most common cause of illness among university students. Information-seeking behavior related to STIs is a means by which individuals sought information related to sexual health, disease, health risk, and health promotion. Communicating STIs and sexual risk behaviors during youth, particularly among university students, is effective in reducing STI-related problems. Lack of access to health information, lack of communication, and insufficient information about STIs are key issues that have contributed to the high prevalence of STIs. In Ethiopia, information-seeking behavior related to STIs and information use culture for improving the sexual health of individuals and the communities is limited. Therefore, the purpose of this study was to assess STI information-seeking behavior and its associated factors among students at the University of Gondar.

More than half of the students sought STI-related information seeking in the past year. From those STI-related information seekers, the majority of students preferred the internet as a primary source for STI-related information. Field of study, year of study, internet access, digital literacy, sexual experiences, had STI symptoms, Perceived susceptibility, and perceived severity of STI were significant factors associated with STI information-seeking. Students' STI information-seeking behavior could be improved by increasing digital literacy and enhancing computer and internet access.

Bacterial Vaginosis and Its Association With Incident Trichomonas vaginalis Infections: A Systematic Review and Meta-Analysis

BACKGROUND

Bacterial vaginosis (BV) has been associated with an increased risk for acquisition of human immunodeficiency virus and sexually transmitted infections. We evaluated the association between BV and incident Trichomonas vaginalis (TV) infection in women.

METHODS

MEDLINE and ClinicalTrials.gov were searched for articles published between January 1, 1980, and May 7, 2021. Observational studies in women that evaluated the relationship between having/not having BV and the risk for acquiring TV were included.

RESULTS

Fourteen studies were included in the systematic review; 12 studies were included in meta-analyses involving 18,424 participants. Most studies used Nugent scoring to diagnose BV. For TV diagnosis, 12 studies used wet mount microscopy or culture, and 2 used nucleic acid amplification tests. There was diversity in the measures of association used, so an overall effect size could not be calculated. The majority of studies reported odds ratios, which showed an increased risk of incident TV among women with BV versus without BV (adjusted odds ratio, 1.87; 95% confidence interval, 1.45-2.40; P = 0.007). However, there were heterogeneity and potential confounding factors (eg, age, sexual partners) reported among studies.

CONCLUSIONS

This systematic review and meta-analysis provide evidence for a nearly 2-fold higher risk for acquiring TV among women with BV compared with women without BV.

Changes in self-reported sexually transmitted infections and symptoms among married couples in India from 2006 to 2016: a repeated cross-sectional multivariate analysis from nationally representative data

OBJECTIVE

To assess the changes in prevalence of past-year self-reported sexually transmitted infections (STIs) and its symptoms among married couples between 2006 and 2016 in India, overall and by socioeconomic status.

DESIGN

This cross-sectional study uses the two most recent waves (2005-2006 vs 2015-2016) of nationally representative health surveys in India. We examined the changes of self-reported STI and symptoms among married couples aged 15-54 by overall and by socioeconomic status. Adjusted logistic regression was used to assess the changes, accounting for covariates and the complex survey design.

SETTING

Cross-sectional, nationally representative population-based survey in 2005-2006 and 2015-2016 from National Family Health Survey data from Demographic and Health Survey.

PARTICIPANTS

39 257 married couples aged 15-49 years for the 2005-2006 survey wave and 63 696 married couples aged 15-49 years for the 2015-2016 wave.

OUTCOME MEASURE

Self-reported STI was used as a primary outcome measure.

RESULTS

In 2016, 2.5% of married women reported having had an STI in the past year, a significant increase from 1.6% in 2006 (p<0.001). The past-year self-reported STI prevalence among married men significantly increased from 0.5% in 2006 to 1.1% in 2016 (p<0.001). Adjusted results showed that the uptrend of couples' self-reported STI was more significant among those whose husbands are currently employed and those families in middle or higher wealth quintiles. Alarmingly, among couples who reported STI or symptoms, they were less likely to seek advice or treatment in 2016 as compared with 2006 (adjusted OR=0.50, p<0.001, 95% CI=0.40 to 0.61).

CONCLUSION

The study identifies a substantial increase in self-reported STI prevalence with a notable treatment seeking gap among married couples in India over the past decade.

Prevalence of Sexual Transmitted Infections (STIs) and Un-Protected Sex in Temporary Marriage in Iran: A Systematic Review and Meta-Analysis

Background:

Temporary marriage (TM) is legitimate sexual relations without social, moral approval, which can be a threat to individuals’ health, it is a risk factor for spread of Sexual Transmitted Infections (STIs). Therefore, it is necessary to identify and control STIs in TM-individuals and subsequent save of “society health”. In this meat-analysis, we examined the prevalence of STIs in TM in Iran. We further examined un-protected sex among TM-individuals.

Method:

Up to Feb 2020, we searched international and national electronic databases identify to published studies on the prevalence of STIs in TM. We estimated the prevalence of STIs in TM using a random-effect pooled estimate analysis approach.

Results:

Totally, we retrieved 1616 studies from the previously mentioned databases, of which, 18 met the eligibility criteria, published from 1995 to 2020 in different provinces. The total sample size of the included studied contained 2056 TM-individuals, of which 368 were found with STIs and 955 with unprotected sex. The pooled prevalence of STIs and unprotected sex among TM women was 39% (95%CI: 24% to 54%), 55% (95%CI: 40% to 70%)

Conclusion:

STI and unprotected sex are high among TM-individuals which call an urgent need for community and health care providers to provide especially designed medical and psycho-social supportive care services in a safe and unprejudiced environment for TM-individuals. Furthermore, untrained health care providers for TM-individuals, under reporting, social stigma should be taken in to account. Denying the presence of such realities, does not eradicate the facts but results in catastrophic public health problems.

Predictive functional analysis reveals inferred features unique to cervicovaginal microbiota of African women with bacterial vaginosis and high-risk human papillomavirus infection

Mounting evidence suggests that Lactobacillus species may not necessarily be the sine qua non of healthy cervicovaginal microbiota (CVM), especially among reproductive-age African women. A majority of African women have high-diversity non-Lactobacillus-dominated CVM whose bacterial functions remain poorly characterized. Functional profiling of the CVM is vital for investigating human host-microbiota interactions in health and disease. Here, we investigated the functional potential of L. iners-dominated and high-diversity non-Lactobacillus-dominated CVM of 75 African women with and without bacterial vaginosis (BV) and high-risk human papillomavirus (HR-HPV) infection. Functional contents were predicted using PICRUSt. Microbial taxonomic diversity, BV, and HR-HPV infection statuses were correlated with the inferred functional composition of the CVM. Differentially abundant inferred functional categories were identified using linear discriminant analysis (LDA) effect size (LEfSe) (p-value <0.05 and logarithmic LDA score >2.0). Of the 75 women, 56 (74.7%), 35 (46.7%), and 29 (38.7%) had high-diversity non-Lactobacillus-dominated CVM, BV, and HR-HPV infection, respectively. Alpha diversity of the inferred functional contents (as measured by Shannon diversity index) was significantly higher in women with high-diversity non-Lactobacillus-dominated CVM and BV than their respective counterparts (H statistic ≥11.5, q-value <0.001). Ordination of the predicted functional metagenome content (using Bray-Curtis distances) showed that the samples segregated according to the extent of microbial taxonomic diversity and BV (pseudo-F statistic ≥19.6, q-value = 0.001) but not HR-HPV status (pseudo-F statistic = 1.7, q-value = 0.159). LEfSe analysis of the inferred functional categories revealed that transport systems (including ABC transporters) and transcription factors were enriched in high-diversity CVM. Interestingly, transcription factors and sporulation functional categories were uniquely associated with high-diversity CVM, BV, and HR-HPV infection. Our predictive functional analysis reveals features unique to high-diversity CVM, BV and HR-HPV infections. Such features may represent important biomarkers of BV and HR-HPV infection. Our findings require proof-of-concept functional studies to examine the relevance of these potential biomarkers in women's reproductive health and disease.

Prevalence of Neisseria gonorrhoeae infection among women of reproductive age in sub-Saharan Africa: a systematic review and meta-analysis

OBJECTIVE

Neisseria gonorrhoeae infection is a global, major public health problem. It is the second leading bacterial sexually transmitted infection (STI) in sub-Saharan Africa and worldwide. As study findings on the topic are inconsistent, we conducted a systematic review and meta-analysis to determine the pooled prevalence of N. gonorrhoeae infection in sub-Saharan Africa among reproductive-aged women.

METHODS

Published studies were systematically retrieved from PubMed, Embase, CINHAL and Science Direct. Their quality was measured using the Joanna Briggs Institute critical appraisal checklist for studies reporting prevalence data, and the score of each included study had to meet at least 4.5 out of 9 indicators of quality.

RESULTS

The meta-analysis of 35 studies showed that the pooled prevalence of N. gonorrhoeae infection among reproductive-aged women in sub-Saharan Africa was 3.28% (95% confidence interval 2.61%, 3.94%).

CONCLUSION

The prevalence of N. gonorrhoeae infection was higher than that found in other studies carried out in the region. The results suggest that greater attention should be paid to the primary prevention of N. gonorrhoeae. We recommend the implementation of STI education for reproductive-aged women and the use of specific and rapid diagnostic testing for N. gonorrhoeae infection in STI clinics. N. gonorrhoeae screening and treatment should be integrated into in- and outpatient clinics to reduce infection among reproductive-aged women.

The Penile Microbiota in Uncircumcised and Circumcised Men: Relationships With HIV and Human Papillomavirus Infections and Cervicovaginal Microbiota

While the human microbiota especially that of the gut, cervix, and vagina continue to receive great attention, very little is currently known about the penile (glans, coronal sulcus, foreskin, and shaft) microbiota. The best evidences to date for the potential role of the penile microbiota in human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs) acquisition have come from studies examining medical male circumcision. We are still at the foothills of identifying specific penile bacteria that could be associated with increased risk of STI/HIV acquisition. In this review, we summarize the available literature on the human penile microbiota and how it is impacted by circumcision. We also discuss the potential role of penile microbiota in STIs and its impact on cervicovaginal microbiota. Taken together, the findings from the penile microbiota studies coupled with observational studies on the effect of male circumcision for reduction of STI/HIV infection risk suggest that specific penile anaerobic bacteria such as Prevotella spp. potentially have a mechanistic role that increases the risk of genital infections and syndromes, including bacterial vaginosis in sexual partners. Although penile Corynebacterium and Staphylococcus have been associated with healthy cervicovaginal microbiota and have been found to increase following male circumcision, further investigations are warranted to ascertain the exact roles of these bacteria in the reproductive health of men and women. This review aims to address existing gaps and challenges and future prospects in the penile microbiota research. The information described here may have translational significance, thereby improving reproductive health and management of STI/HIV.

Gender differences in risk taking behaviors for Chlamydia trachomatis

Chlamydia trachomatis (CT) is a global problem. We compared the risk taking behaviors for CT infection between men and women. Adults (2299 females, 5559 males) were administered the Risk Behavior Assessment. In women, CT was associated with candidiasis, in men with gonorrhea, genital warts, and syphilis. Risk factors for both genders were trading sex for money, use of marijuana for women, and use of Ecstasy and Viagra for men. Those with CT had higher risk perception for HIV infection and were more likely to obtain HIV testing. Patient teaching and concurrent testing for HIV and CT are imperative.

Antimicrobial resistance in Clostridium difficile ribotype 017

Introduction: Antimicrobial resistance (AMR) played an important role in the initial outbreaks of Clostridium difficile infection (CDI) in the 1970s. C. difficile ribotype (RT) 017 has emerged as the major strain of C. difficile in Asia, where antimicrobial use is poorly regulated. This strain has also caused CDI outbreaks around the world for almost 30 years. Many of these outbreaks were associated with clindamycin and fluoroquinolone resistance. AMR and selective pressure is likely to be responsible for the success of this RT and may drive future outbreaks.Areas covered: This narrative review summarizes the prevalence and mechanisms of AMR in C. difficile RT 017 and transmission of these AMR mechanisms. To address these topics, reports of outbreaks due to C. difficile RT 017, epidemiologic studies with antimicrobial susceptibility results, studies on resistance mechanisms found in C. difficile and related publications available through Pubmed until September 2019 were collated and the findings discussed.Expert opinion: Primary prevention is the key to control CDI. This should be achieved by developing antimicrobial stewardship in medical, veterinary and agricultural practices. AMR is the key factor that drives CDI outbreaks, and methods for the early detection of AMR can facilitate the control of outbreaks.

Silhouette width using generalized mean-A flexible method for assessing clustering efficiency

Cluster analysis plays vital role in pattern recognition in several fields of science. Silhouette width is a widely used index for assessing the fit of individual objects in the classification, as well as the quality of clusters and the entire classification. Silhouette combines two clustering criteria, compactness and separation, which imply that spherical cluster shapes are preferred over others-a property that can be seen as a disadvantage in the presence of complex, nonspherical clusters, which is common in real situations. We suggest a generalization of the silhouette width using the generalized mean. By changing the p parameter of the generalized mean between -∞ and +∞, several specific summary statistics, including the minimum, maximum, the arithmetic, harmonic, and geometric means, can be reproduced. Implementing the generalized mean in the calculation of silhouette width allows for changing the sensitivity of the index to compactness versus connectedness. With higher sensitivity to connectedness, the preference of silhouette width toward spherical clusters should reduce. We test the performance of the generalized silhouette width on artificial data sets and on the Iris data set. We examine how classifications with different numbers of clusters prepared by different algorithms are evaluated, if p is set to different values. When p was negative, well-separated clusters achieved high silhouette widths despite their elongated or circular shapes. Positive values of p increased the importance of compactness; hence, the preference toward spherical clusters became even more detectable. With low p, single linkage clustering was deemed the most efficient clustering method, while with higher parameter values the performance of group average, complete linkage, and beta flexible with beta = -0.25 seemed better. The generalized silhouette allows for adjusting the contribution of compactness and connectedness criteria, thus avoiding underestimation of clustering efficiency in the presence of clusters with high internal heterogeneity.

Identifying population segments for effective intervention design and targeting using unsupervised machine learning: an end-to-end guide

One-size-fits-all interventions that aim to change behavior are a missed opportunity to improve human health and well-being, as they do not target the different reasons that drive people's choices and behaviors. Psycho-behavioral segmentation is an approach to uncover such differences and enable the design of targeted interventions, but is rarely implemented at scale in global development. In part, this may be due to the many choices program designers and data scientists face, and the lack of available guidance through the process. Effective segmentation encompasses conceptualization and selection of the dimensions to segment on, which often requires the design of suitable qualitative and quantitative primary research. The choice of algorithm and its parameters also profoundly shape the resulting output and how useful the results are in the field. Analytical outputs are not self-explanatory and need to be subjectively evaluated and described. Finally, segments can be prioritized and targeted with matching interventions via appropriate channels. Here, we provide an end-to-end overview of all the stages from planning, designing field-based research, analyzing, and implementing a psycho-behavioral segmentation solution. We illustrate the choices and critical steps along the way, and discuss a case study of segmentation for voluntary medical male circumcision that implemented the method described here. Though our examples mostly draw on health interventions in the developing world, the principles in this approach can be used in any context where understanding human heterogeneity in driving behavior change is valuable.

Identifying population segments for effective intervention design and targeting using unsupervised machine learning: an end-to-end guide

One-size-fits-all interventions that aim to change behavior are a missed opportunity to improve human health and well-being, as they do not target the different reasons that drive people’s choices and behaviors. Psycho-behavioral segmentation is an approach to uncover such differences and enable the design of targeted interventions, but is rarely implemented at scale in global development. In part, this may be due to the many choices program designers and data scientists face, and the lack of available guidance through the process. Effective segmentation encompasses conceptualization and selection of the dimensions to segment on, which often requires the design of suitable qualitative and quantitative primary research. The choice of algorithm and its parameters also profoundly shape the resulting output and how useful the results are in the field. Analytical outputs are not self-explanatory and need to be subjectively evaluated and described. Finally, segments can be prioritized and targeted with matching interventions via appropriate channels. Here, we provide an end-to-end overview of all the stages from planning, designing field-based research, analyzing, and implementing a psycho-behavioral segmentation solution. We illustrate the choices and critical steps along the way, and discuss a case study of segmentation for voluntary medical male circumcision that implemented the method described here. Though our examples mostly draw on health interventions in the developing world, the principles in this approach can be used in any context where understanding human heterogeneity in driving behavior change is valuable.

An analysis of the development assistance for health (DAH) allocations for STD control in Africa

The Sustainable Development Goals set by the United Nations recognize the importance of making progress in the eradication and treatment of sexually transmitted deceases (STD). STD are among the most widespread diseases in the world and have the highest prevalence in Sub-Saharan Africa. The current study explored the associations between the allocation of the development assistance for health (DAH) in 54 African countries and key development indicators - STD incidence, Gross Domestic Product per capita, health expenditure, and life expectancy at birth. It employed descriptive statistical methods, the matrix scatter plot analysis and the Pearson correlation test for this purpose. The findings indicated that there was a considerable increase in the volume of the DAH given to control and prevent STD in Africa over the period of 2002-2011. A statistically significant positive association was detected between the STD incidence and the health aid allocations. At the same time, the imbalance in the distribution of the health aid between the major and minor aid recipients in the continent increased. The study concludes by discussing policy implications that can be drawn from these findings.

Association between substance use and concurrent sexual relationships among urban slum dwellers in Nairobi, Kenya

While the overall incidence and prevalence of HIV/AIDS are declining in Africa, substance use-related HIV/AIDS is on the rise. The main objectives of this study were to elicit the types of commonly used substances and to examine the association between substance use and concurrent sexual relationships among slum dwellers in Kenya. Freelisting elicitation techniques were used to identify the most commonly used substances using 53 key informants. This was followed by a self-administered, structured questionnaire using a convenience sample of 506 participants. Findings from our freelisting analysis produced 27 substances that were used in the community. Analysis of the survey data shows that participants who reported using substances in the past three months were more likely to be involved in concurrent sexual relationships than those who did not (86.2% vs. 74.0%; p = .002). In the multivariable model, the odds of ever having concurrent sexual relationships were higher among participants who used any substance in the past three months (aOR 2.46; 95% CI 1.37-4.42, p < .01). The observed association between substance use and concurrent sexual relationships may be influenced by social and economic factors such as poverty and lack of opportunity among urban slum dwellers.

Differential sexual network connectivity offers a parsimonious explanation for population-level variations in the prevalence of bacterial vaginosis: a data-driven, model-supported hypothesis

BACKGROUND

The prevalence of bacterial vaginosis (BV) and vaginal microbiota types varies dramatically between different populations around the world. Understanding what underpins these differences is important, as high-diversity microbiotas associated with BV are implicated in adverse pregnancy outcomes and enhanced susceptibility to and transmission of sexually transmitted infections.

MAIN TEXT

We hypothesize that these variations in the vaginal microbiota can, in part, be explained by variations in the connectivity of sexual networks. We argue: 1) Couple-level data suggest that BV-associated bacteria can be sexually transmitted and hence high sexual network connectivity would be expected to promote the spread of BV-associated bacteria. Epidemiological studies have found positive associations between indicators of network connectivity and the prevalence of BV; 2) The relationship between BV prevalence and STI incidence/prevalence can be parsimoniously explained by differential network connectivity; 3) Studies from other mammals are generally supportive of the association between network connectivity and high-diversity vaginal microbiota.

CONCLUSION

To test this hypothesis, we propose a combination of empirical and simulation-based study designs.

It's the network, stupid: a population's sexual network connectivity determines its STI prevalence

There is little consensus as to why sexually transmitted infections (STIs), including HIV and bacterial vaginosis (BV) are more prevalent in some populations than others. Using a broad definition of sexual network connectivity that includes both structural and conductivity-related factors, we argue that the available evidence suggests that high prevalence of traditional STIs, HIV and BV can be parsimoniously explained by these populations having more connected sexual networks. Positive feedback, whereby BV and various STIs enhance the spread of other STIs, then further accentuates the spread of BV, HIV and other STIs. We review evidence that support this hypothesis and end by suggesting study designs that could further evaluate the hypothesis, as well as implications of this hypothesis for the prevention and management of STIs.

It's the network, stupid: a population's sexual network connectivity determines its STI prevalence

There is little consensus as to why sexually transmitted infections (STIs), including HIV and bacterial vaginosis (BV) are more prevalent in some populations than others. Using a broad definition of sexual network connectivity that includes both structural and conductivity-related factors, we argue that the available evidence suggests that high prevalence of traditional STIs, HIV and BV can be parsimoniously explained by these populations having more connected sexual networks. Positive feedback, whereby BV and various STIs enhance the spread of other STIs, then further accentuates the spread of BV, HIV and other STIs. We review evidence that support this hypothesis and end by suggesting study designs that could further evaluate the hypothesis, as well as implications of this hypothesis for the prevention and management of STIs.

Knowledge and risk perception of sexually transmitted infections and relevant health care services among high school students in the Platfontein San community, Northern Cape Province, South Africa

Background

The historically marginalized Platfontein San youths have a high rate of teenage pregnancies and sexually transmitted infections (STIs). The aim of the study was to assess the knowledge and perception of male and female school-going youths in Platfontein of STIs and HIV/AIDS, and the health care services that are available to them.

Participants and methods

A descriptive cross-sectional survey with a sample of 201 learners in grades 6–12 at the !Xunkwesa Combined School in Platfontein was conducted in July 2007. A pretested self-administered questionnaire was used for data collection.

Results

The study found that STI knowledge was 70.1% and HIV and AIDS was 11.9%. Perceptions of risk among the learners were uniformly low; 24% for contracting a STI and 26% for HIV. About 59% (n=119) of the respondents were either unaware or not sure of the primary health care (PHC) services within the community. Overall, 65% of the students reported using PHC services while 35% exclusively used traditional healers. Slightly less than half (43%) of the learners acquired information about sexual and reproductive health through the Life Skills curriculum at school.

Conclusion

The study highlights the importance of increasing HIV awareness and inculcating sexual and reproductive health into the school curriculum. The study further shows the imperative need to recognize the role of traditional medicine in the health care choices of this community. Traditional value systems need to be incorporated into the way that education and health care is proposed to the community leaders, to increase acceptance and utilization of health services.

Chlorinated metronidazole as a promising alternative for treating trichomoniasis

Trichomoniasis is the most common non-viral, sexually transmitted infection affecting humans worldwide. The main treatment for trichomoniasis is metronidazole (MTZ). However, adverse effects and reports of resistance have stimulated the development of therapeutic alternatives. The ease of manipulation of the side chains of MTZ coupled with its safety makes this molecule attractive for the development of new drugs. In this context, we evaluated the activity of the chlorinated MTZ derivative, MTZ-Cl, on sensitive and resistant strains of Trichomonas vaginalis. MTZ-Cl presented a remarkable activity against both sensitive and resistant strains. In vitro and in vivo toxicity assays indicated that the new molecule is safe for future clinical trials. Furthermore, we noticed different rates of free radical production between the sensitive and resistant strains. MTZ-Cl induced a higher release of nitric oxide (NO, ~ 9000 a.u.) by both sensitive and resistant strains. However, the sensitive strain produced a greater amount of H₂O₂ (~ 1,800,000 a.u.) and superoxide radicals (~ 350,000 a.u.) in the presence of MTZ. In the resistant strain, production of these radicals was more prominent when MTZ-Cl was used. Collectively, these results suggest that NO is an important molecule in the trichomonacidal activity against resistant and sensitive strains, suggesting an alternative pathway for MTZ-Cl activation. We highlight the high trichomonacidal potential of MTZ-Cl, improving the effectiveness of treatment and reducing side effects. In addition, MTZ-Cl is derived from a well-established drug on the world market that presents low toxicity to human cells, suggesting its safety to proceed with future clinical trials.

Genital Chlamydia trachomatis and Neisseria gonorrhoeae infections among women in sub-Saharan Africa: A structured review

Chlamydia trachomatis and Neisseria gonorrhoeae constitute major public health problems among women, but the burden of infection in sub-Saharan Africa is poorly documented. We conducted a structured review of the prevalence and incidence of genital, oral and anal C. trachomatis and N. gonorrhoeae infection in women in sub-Saharan Africa. We searched Medline, EMBASE and Web of Science over a 10-year period for studies on epidemiology of genital, oral and anal chlamydial infection and gonorrhoea in women in all countries of sub-Saharan Africa. We assessed geographic and demographic differences in prevalence and incidence of infection; weighted mean prevalence estimates were calculated with a random-effect model. A total of 102 study results were included, with data available for 24/49 of sub-Saharan countries. The weighted prevalence of chlamydial infection was lower among women in community-based studies (3.9%; 95% CI: 2.9-5.1%) than for women recruited at primary healthcare facilities (6.0%; 95% CI: 4.2-8.4%, p < 0.001); the same was observed for gonorrhoea (2.2%; 95% CI: 1.2-4.0% vs. 4.2%; 95% CI: 3.2-5.6%, p < 0.001). Prevalence of Chlamydia among sex workers was 5.5% (95% CI: 4.2-7.3%) and gonorrhoea 7.6% (95% CI: 5.4-11%). Seven studies reported on incidence which varied between 0.75-28 and 2.8-17 per 100 person-years-at-risk for chlamydial infection and gonorrhoea, respectively. Only two studies reported on anal infections and one on oral infection. This overview underscores the considerable incidence and prevalence of genital C. trachomatis and N. gonorrhoeae in women in different settings in sub-Saharan Africa. Better control strategies are warranted to reduce the burden of infection and to prevent long-term complications of these infections.

Prevalence of Chlamydia trachomatis Infection and Its Association with Sexual Behaviour and Alcohol Use in the Population Living in Separated and Segregated Roma Settlements in Eastern Slovakia

The aim of the study was to explore sexual behaviour and the occurrence of Chlamydia trachomatis (CT) infection in the population living in Roma settlements compared to the majority population in Slovakia and to assess the association between alcohol use and sexual behaviour within both populations. A cross-sectional population-based Hepa-Meta study was conducted in Slovakia in 2011. The final sample comprised 452 Roma and 403 non-Roma respondents. The occurrence of CT was detected by direct proof of the pathogen by PCR. The association between alcohol use and the prevalence of risky sexual behaviour were assessed using a logistic regression. First intercourse at age 15 or younger was reported by 27.9% of Roma (vs. 4.5% of non-Roma); 93.4% of Roma (vs. 77.9% of non-Roma) used condom inconsistently, 22.8% of Roma (vs. 43.9% of non-Roma) used a condom for protection from unwanted pregnancies and only 8.8% of Roma (vs. 21.8% of non-Roma) due to protection against infectious diseases. However, Roma reported having had five or more sexual partners less often compared to the majority (11.5% of Roma vs. 20.6% of non-Roma). Binge drinking at least once a month was associated with a higher number of sexual partners in both groups, but not with condom non-use. The prevalence of CT infection in the Roma population was higher (3.8%) compared to non-Roma (2.7%); however, the difference was not statistically significant. Our study found no differences in the prevalence of CT infection between Roma and non-Roma despite differences in sexual behaviour. Roma begin their sexual life earlier and have unprotected sex more often, but on the other hand, they seem to be much more restrained in terms of the number of sexual partners compared to the majority population.

Case Report of Urethritis in a Male Patient Infected with Two Different Isolates of Multiple Drug-Resistant Neisseria gonorrhoeae

We report a brief description of a case suffering from bacterial urethritis, conjunctivitis, and arthritis, caused by two different isolates of multiple drug-resistant Neisseria gonorrhoeae. Initial diagnosis was dependent on the patient history, clinical findings, symptoms, and the bacteriological data. Polymerase chain reaction confirmed the identification of the pathogens. Random amplified polymorphic DNA revealed two different patterns. Susceptibility testing was performed using Kirby-Bauer disk diffusion method and the minimum inhibitory concentration was also determined. It revealed multiple drug resistance associated with β-lactamase production. Only gentamicin, rifampicin, and azithromycin were active against the test pathogens. A dual therapy was initiated using gentamicin as well as azithromycin to treat the possible co-infection with Chlamydia trachomatis. Complete recovery of the patient achieved with resolved symptoms a week later.

Strong associations between national prevalence of various STIs suggests sexual network connectivity is a common underpinning risk factor

Background

If national peak Human Immunodeficiency Virus (HIV) prevalence is positively associated with the prevalence of other sexually transmitted infections (STIs) from before or early on in the HIV epidemics this would suggest common underlying drivers.

Methods

Pearson’s correlations were calculated between the prevalence of seven STIs at a country-level: chlamydia, gonorrhoea, trichomoniasis, syphilis, bacterial vaginosis, herpes simplex virus-2 (HSV-2) and HIV.

Results

The prevalence of all the STIs was highest in the sub-Saharan African region excluding chlamydia. The prevalence of all seven STIs were positively correlated excluding chlamydia. The correlations were strongest for HIV-HSV-2 (r = 0.85, P < 0.0001) and HSV-2-trichomoniasis (r = 0.82, P < 0.0001).

Conclusion

Our results of a generally positive association between the prevalences of a range of STIs suggests that higher prevalences were driven by common underlying determinants. We review different types of evidence which suggest that differential sexual connectivity is a plausible common determinant.

Patterns of prevalent HPV and STI co-infections and associated factors among HIV-negative young Western Cape, South African women: the EVRI trial

OBJECTIVE

To estimate the prevalence and describe the patterns of concurrent human papillomavirus (HPV) and STIs and associated factors among HIV-negative young Western Cape, South African women participating in the Efficacy of HPV Vaccine to Reduce HIV Infection (EVRI) trial.

METHODS

HIV-negative women aged 16-24 years old were enrolled in the EVRI trial (NCT01489527) and randomised to receive the licensed four-valent HPV vaccine or placebo. At study entry, participants were clinically evaluated for five STIs: herpes simplex virus type 2 (HSV-2), chlamydia, gonorrhoea, syphilis and disease-causing HPV genotypes (6/11/16/18/31/33/35/39/45/51/52/56/58/59/68). Demographic and sexual history characteristics were compared among women with STI co-infections, single infection and no infection using Pearson χ² and Mann-Whitney tests. ORs were calculated to evaluate factors associated with STI co-infection prevalence.

RESULTS

Among 388 young women, STI co-infection prevalence was high: 47% had ≥2 concurrent STIs, 36% had a single STI and 17% had none of the five evaluated STIs. HPV/HSV-2 (26%) was the most prevalent co-infection detected followed by HPV/HSV-2/Chlamydia trachomatis (CT) (17%) and HPV/CT (15%). Co-infection prevalence was independently associated with alcohol use (adjusted OR=2.01, 95% CI 1.00 to 4.06) and having a sexual partner with an STI (adjusted OR=6.96, 95% CI 1.53 to 30.08).

CONCLUSIONS

Among high-risk young women from underserved communities such as in Southern Africa, a multicomponent prevention strategy that integrates medical and behavioural interventions targeting both men and women is essential to prevent acquisition of concurrent STI infections and consequent disease.

TRIAL REGISTRATION NUMBER

NCT01489527; Post-results.

Development and evaluation of an enzyme-linked immunosorbent assay for the detection of antibodies to a common urogenital derivative of Chlamydia trachomatis plasmid-encoded PGP3

BACKGROUND

Urogenital infection with Chlamydia trachomatis is the most commonly diagnosed sexually transmitted infection in the developed world. Accurate measurement and therefore understanding the seroprevalence of urogenital C. trachomatis infections requires a rigorously optimised and validated ELISA. Previous ELISAs based on the C. trachomatis plasmid-encoded protein, PGP3, have been described but lack standardisation and critical controls or use a less common PGP3 as the capture antigen.

METHODOLOGY/PRINCIPAL FINDINGS

A sensitive and specific indirect ELISA was developed based on recombinant PGP3 derived from a urogenital strain of C. trachomatis, serovar E (pSW2), using a rigorous validation protocol. Serum samples were collected from 166 genitourinary medicine (GUM) clinic patients diagnosed as positive or negative for urogenital C. trachomatis infection by nucleic acid amplification testing (NAATs). Overall sensitivity and specificity compared to NAATs was 68.18% and 98.0%, respectively. Sensitivities for female and male samples were 71.93% and 64.15%, respectively. Comparison of samples from these patients diagnosed positive for C. trachomatis by NAAT and patients diagnosed negative by NAAT revealed statistical significance (p≤0.0001).

CONCLUSIONS

We have developed and validated a sensitive and specific ELISA to detect anti-PGP3 antibodies as an indicator of past and current infection to C. trachomatis using PGP3 from a common urogenital strain. It is anticipated that this assay will be used for seroepidemiological analysis of urogenital C. trachomatis in populations.

Effect of immediate initiation of antiretroviral therapy on risk of severe bacterial infections in HIV-positive people with CD4 cell counts of more than 500 cells per μL: secondary outcome results from a randomised controlled trial

BACKGROUND

The effects of antiretroviral therapy on risk of severe bacterial infections in people with high CD4 cell counts have not been well described. In this study, we aimed to quantify the effects of immediate versus deferred ART on the risk of severe bacterial infection in people with high CD4 cell counts in a preplanned analysis of the START trial.

METHODS

The START trial was a randomised controlled trial in ART-naive HIV-positive patients with CD4 cell count of more than 500 cells per μL assigned to immediate ART or deferral until their CD4 cell counts were lower than 350 cells per μL. We used Cox proportional hazards regression to model time to severe bacterial infection, which was defined as a composite endpoint of bacterial pneumonia (confirmed by the endpoint review committee), pulmonary or extrapulmonary tuberculosis, or any bacterial infectious disorder of grade 4 severity, that required unscheduled hospital admissions, or caused death. This study is registered with ClinicalTrials.gov, number NCT00867048.

FINDINGS

Patients were recruited from April 15, 2009, to Dec 23, 2013. The data cutoff for follow-up was May 26, 2015. Of 4685 HIV-positive people enrolled, 120 had severe bacterial infections (immediate-initiation group n=34, deferred-initiation group n=86; median 2·8 years of follow-up). Immediate ART was associated with a reduced risk of severe bacterial infection compared with deferred ART (hazard ratio [HR] 0·39, 95% CI 0·26-0·57, p<0·0001). In the immediate-initiation group, average neutrophil count over follow-up was 321 cells per μL higher, and average CD4 cell count 194 cells per μL higher than the deferred-initiation group (p<0·0001). In univariable analysis, higher time-updated CD4 cell count (0·78, 0·71-0·85, p=0·0001) was associated with reduced risk of severe bacterial infection. Time-updated neutrophil count was not associated with severe bacterial infection. After adjustment for time-updated factors in multivariable analysis, particularly the CD4 cell count, the HR for immediate-initiation group moved closer to 1 (HR 0·84, 0·50-1·41, p=0·52). These results were consistent when subgroups of the severe bacterial infection composite were analysed separately.

INTERPRETATION

Immediate ART reduces the risk of several severe bacterial infections in HIV-positive people with high CD4 cell count. This is partly explained by ART-induced increases in CD4 cell count, but not by increases in neutrophil count.

FUNDING

National Institute of Allergy and Infectious Diseases National Institutes of Health, Agence Nationale de Recherches sur le SIDA et les Hépatites Virales, Bundesministerium für Bildung und Forschung, European AIDS Treatment Network, Australian National Health and Medical Research Council, UK National Institute for Health Research and Medical Research Council, Danish National Research Foundation.

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.

Current Concepts for Genital Herpes Simplex Virus Infection: Diagnostics and Pathogenesis of Genital Tract Shedding

Herpes simplex virus 2 (HSV-2) is a DNA virus that is efficiently transmitted through intimate genital tract contact and causes persistent infection that cannot be eliminated. HSV-2 may cause frequent, symptomatic self-limited genital ulcers, but in most persons infection is subclinical. However, recent studies have demonstrated that the virus is frequently shed from genital surfaces even in the absence of signs or symptoms of clinical disease and that the virus can be transmitted during these periods of shedding. Furthermore, HSV-2 shedding is detected throughout the genital tract and may be associated with genital tract inflammation, which likely contributes to increased risk of HIV acquisition. This review focuses on HSV diagnostics, as well as what we have learned about the importance of frequent genital HSV shedding for (i) HSV transmission and (ii) genital tract inflammation, as well as (iii) the impact of HSV-2 infection on HIV acquisition and transmission. We conclude with discussion of future areas of research to push the field forward.

The Global Epidemiology of Syphilis in the Past Century - A Systematic Review Based on Antenatal Syphilis Prevalence

BACKGROUND

How can we explain the uneven decline of syphilis around the world following the introduction of penicillin? In this paper we use antenatal syphilis prevalence (ASP) to investigate how syphilis prevalence varied worldwide in the past century, and what risk factors correlate with this variance.

METHODS

1) A systematic review using PubMed and Google Scholar was conducted to identify countries with published data relating to ASP estimates from before 1952 until the present. Eleven countries were identified (Canada, Denmark, Finland, India, Japan, Norway, Singapore, South Africa, United States of America (USA), United Kingdom (UK) and Zimbabwe). The ASP epidemic curve for each population was depicted graphically. In South Africa and the USA, results are reported separately for the black and white populations. 2) National antenatal syphilis prevalence estimates for 1990 to 1999 and 2008 were taken from an Institute for Health Metrics and Evaluation database on the prevalence of syphilis in low risk populations compiled for the Global Burden of Diseases study and from a recent review paper respectively. National ASPs were depicted graphically and regional median ASPs were calculated for both time periods. 3) Linear regression was used to test for an association between ASP in 1990-1999 and 2008 and four risk factors (efficacy of syphilis screening/treatment, health expenditure, GDP per capita and circumcision prevalence). WHO world regions were included as potential explanatory variables.

RESULTS

In most populations, ASP dropped to under 1% before 1960. In Zimbabwe and black South Africans, ASP was high in the pre-penicillin period, dropped in the post-penicillin period, but then plateaued at around 6% until the end of the 20th century when ASP dropped to just above 1%. In black Americans, ASP declined in the post penicillin period, but plateaued at 3-5% thereafter. ASP was statistically significantly higher in sub-Saharan Africa in 1990-1999 and 2008 than in the other world regions (P < 0.001). On multivariate analysis in both time periods, ASP was only associated with residence in sub-Saharan Africa.

CONCLUSIONS

Further research is necessary to elucidate the reasons for the higher prevalence of syphilis in sub-Saharan Africa.

OsmC and incomplete glycine decarboxylase complex mediate reductive detoxification of peroxides in hydrogenosomes of Trichomonas vaginalis

Osmotically inducible protein (OsmC) and organic hydroperoxide resistance protein (Ohr) are small, thiol-dependent peroxidases that comprise a family of prokaryotic protective proteins central to the defense against deleterious effects of organic hydroperoxides, which are reactive molecules that are formed during interactions between the host immune system and pathogens. Trichomonas vaginalis, a sexually transmitted parasite of humans, possesses OsmC homologues in its hydrogenosomes, anaerobic mitochondrial organelles that harbor enzymes and pathways that are sensitive to oxidative damage. The glycine decarboxylase complex (GDC), which consists of four proteins (i.e., L, H, P and T), is in eukaryotes exclusively mitochondrial enzymatic system that catalyzes oxidative decarboxylation and deamination of glycine. However, trichomonad hydrogenosomes contain only the L and H proteins, whose physiological functions are unknown. Here, we found that the hydrogenosomal L and H proteins constitute a lipoate-dependent redox system that delivers electrons from reduced nicotinamide adenine dinucleotide (NADH) to OsmC for the reductive detoxification of peroxides. Our searches of genome databases revealed that, in addition to prokaryotes, homologues of OsmC/Ohr family proteins with predicted mitochondrial localization are present in various eukaryotic lineages. Therefore, we propose that the novel OsmC-GDC-based redox system may not be limited to T. vaginalis.

Neisseria gonorrhoeae prevalence, incidence and associated risk factors among female sex workers in a high HIV-prevalence area of China

BACKGROUND

Neisseria gonorrhoeae (N. gonorrhoeae) is one of the most prevalent non-ulcerative sexually transmitted infections (STIs) in China, however, the data about N. gonorrhoeae infections are limited in this population. The objective of this study is to determine N. gonorrheae incidence and associated risk factors among female sex workers (FSWs) in China.

METHODS

This serial cross-sectional study was conducted semi-annually among FSWs in a City of Yunnan Province, which constituted an open cohort study. Participants were interviewed and tested for N. gonorrhoeae every 6 months.

RESULTS

During 3 years of follow-up, 64 incident cases of N. gonorrhoeae infection were diagnosed, yielding an overall incidence of 5.9 per 100 person years (PY) (95% confidence interval (CI), 4.53-7.41). Working in higher risk commercial sex venue (adjusted hazard ratio (AHR)=2.7, 95% CI, 1.56-4.55), inconsistently used condoms with clients in previous week (AHR=1.9, 95% CI, 1.07-3.35) and being infected with C. trachomatis (AHR=1.9, 95% CI, 1.06-3.26) were independent risk factors for incident N. gonorrhoeae infection.

CONCLUSIONS

A relatively high prevalence and incidence of N. gonorrhoeae among a prospective cohort of FSWs underscore the urgency for traditional HIV/STIs prevention methods among FSWs, such as condom promotion, screening and treatment of STIs, considering the high prevalence of STIs. Significant attention should focus on FSWs working in higher risk commercial sex venues as they are at higher risk for N. gonorrhoeae and transmission than those in lower risk commercial sex venues.

The incidence of Trichomonas vaginalis infection in women attending nine sexually transmitted diseases clinics in the USA

OBJECTIVES

Trichomoniasis (TV) is associated with an increased risk of acquisition of sexually transmitted diseases (STDs) and HIV. The purpose of this study is to evaluate factors associated with incidence TV among female STD clinic attendees in the USA.

METHODS

Data were collected from women participating in a randomised controlled trial evaluating brief risk reduction counselling at the time of HIV testing to reduce sexually transmitted infections (STIs) incidence in STD clinics. Participants recruited from STD clinics underwent STI testing at baseline and 6-month follow-up. TV testing was performed using Nucleic Acid Amplification Test.

RESULTS

1704 participants completed study assessments. Prevalence of TV was 14.6%, chlamydia 8.6%, gonorrhoea 3.0%, herpes simplex virus 2 44.7% and HIV 0.4%. Cumulative 6-month incidence of TV was 7.5%. Almost 50% of the incident TV cases had TV at baseline and had received treatment. Factors associated with incidence of TV were having chlamydia, TV and HIV at baseline: TV relative risk (RR)=3.37 (95% CI 2.35 to 4.83, p<0.001); chlamydia RR=1.92 (95% CI 1.23 to 2.99, p=0.04); and HIV=1.59 (95% CI 1.01 to 2.50, p=0.047).

CONCLUSIONS

Prevalent and incident TV is common among STD clinic attendees; and baseline TV is the main risk factor for incident TV, suggesting high rates of reinfection or treatment failures. This supports the importance of rescreening women after treatment for TV, evaluating current treatment regimens and programmes to ensure treatment of sexual partners.

CLINICAL TRIAL NUMBER

NCT01154296.

Prevalence of sexually transmitted pathogens associated with HPV infection in cervical samples in a Mexican population

Cervical cancer development has been mainly associated with persistent human papillomavirus (HPV) infections. However, HPV infection is unlikely to be sufficient to cause cervical cancer, and the contribution of other sexually transmitted infections (STIs) could be the determining factor for cervical lesion-progression. The aim of this study was to estimate the prevalence of STIs associated with HPV-positivity in 201 cervical samples from patients who underwent annual routine gynecological exams. The overall prevalence of STIs was 57.7%, and the most frequent infection was Ureaplasma spp (UP) (39.8%), followed by Gardnerella vaginalis (GV) (25.9%), α-HPV (18.4%), Chlamydia trachomatis (CT) (1.5%), and Mycoplasma genitalium (MG) (0.5%). The highest prevalence rate of multiple non-HPV infections was observed for the age-range 31-40; for papillomavirus infection, the age-range was 21-30. In normal cervical samples, HPV16 was the most prevalent genotype (24.3%), followed by genotypes 58 (13.5%) and 52 (10.8%). Intriguingly, HPV18 was not detected in the study population, and genotypes 52 and 58 were found exclusively in samples with abnormal cytology. Papillomavirus infection with oncogenic types was significantly associated with GV (P = 0.025) and strongly associated with multiple non-HPV pathogens (P = 0.002). The following variables correlated significantly with cytological diagnosis of low-grade squamous intraepithelial lesion (LSIL): GV (P = 0.028), multiple non-HPV infections (P = 0.001), and high-risk HPV positivity (P = 0.001). Epidemiological data from this study will contribute to the molecular detection of sexually transmitted pathogens from screening programs to identify those women who are at risk for developing cervical lesions.

Prevalence and correlates of Trichomonas vaginalis infection among female sex workers in a city in Yunnan Province, China

Sexual transmission is the fastest growing route of HIV transmission in China, and Trichomonas vaginalis(TV) can facilitate HIV transmission and acquisition. Our goal was to determine the prevalence and correlates of TV infection among female sex workers (FSWs). This cross-sectional study was conducted in a city of Yunnan Province in southern China, with confidential face-to-face interviews and laboratory tests for TV (wet mount) and other sexually transmitted infections. A total of 734 FSWs participated in the study. The prevalence of TV was 9.0% (95% confidence interval [CI] 7.02-11.30). In multivariate analyses, adjusted odds ratios of TV infection were 3.0 (95% CI 1.47-6.01) for herpes simplex virus type 2 seropositive, 2.4 (95% CI 1.37-4.14) for Chlamydia trachomatis infection, 2.6 (95% CI 1.30-5.31) for genital ulcer, 1.9 (95% CI 1.11-3.30) for starting age in commercial sex <20 years, and 0.5 (95% CI 0.27-0.87) for vaginal douching. We found a relatively high prevalence of TV infection among FSWs in Yunnan Province. A range of control strategies that include TV screening are recommended among FSWs, which could contribute significantly to the disruption of transmission by the provision of immediate treatment.

The Association of HIV Stigma and HIV/STD Knowledge With Sexual Risk Behaviors Among Adolescent and Adult Men Who Have Sex With Men in Ghana, West Africa

Ghanaian men who have sex with men (MSM) have a high HIV seroprevalence, but despite a critical need to address this public health concern, research evidence has been extremely limited on influences on sexual risk behavior among MSM in Ghana. To investigate associations between HIV/STD knowledge, HIV stigma, and sexual behaviors in a sample of MSM in Ghana, we conducted a secondary data analysis of cross-sectional survey data from a non-probability sample of Ghanaian MSM (N = 137). Nearly all the men (93%) had more than one current sex partner (M = 5.11, SD = 7.4). Of those reported partners, the average number of current female sexual partners was 1.1 (SD = 2.6). Overall, knowledge levels about HIV and STDs were low, and HIV stigma was high. There was no age-related difference in HIV stigma. Younger MSM (≤25 years) used condoms less often for anal and vaginal sex than did those over 25. Relative frequency of condom use for oral sex was lower in younger men who had higher STD knowledge and also was lower in older men who reported high HIV stigma. Knowledge and stigma were not associated with condom use for anal or vaginal sex in either age group. These descriptive data highlight the need for the development of intervention programs that address HIV/STD prevention knowledge gaps and reduce HIV stigma in Ghanaian communities. Intervention research in Ghana should address age-group-specific HIV prevention needs of MSM youth.

Bacteriocins and other bioactive substances of probiotic lactobacilli as biological weapons against Neisseria gonorrhoeae

In the search of new antimicrobial agents against Neisseria gonorrhoeae, the bacteriocins-producing probiotic lactobacilli deserve special attention. The inhibitory effects of biosubstances such as organic acids, hydrogen peroxide and each bacteriocin-like inhibitory substance (BLIS) L23 and L60 on the growth of different gonococcal strains were investigated. Different non-treated and treated cell-free supernatants of two probiotic lactobacilli containing these metabolites were used. The aims of this work were (i) to evaluate the antimicrobial activity of the biosubstances produced by two probiotic lactobacilli, estimating the proportion in which each of them is responsible for the inhibitory effect, (ii) to define their minimum inhibitory concentrations (MICs) and, (iii) to determine the potential interactions between these biosubstances against N. gonorrhoeae. The main antimicrobial metabolites were the BLIS-es L23 and L60 in comparison with other biosubstances. Proportionally, their contributions to the inhibition on the gonococcal growth were 87.28% and 80.66%, respectively. The MIC values of bacteriocins were promising since these substances, when diluted, showed considerable inhibitory activity for all gonococci. In the interaction between bacteriocins, 100% of synergism was found on the gonococcal growth. In summary, this study indicates that both L23 and L60 could potentially serve to design new bioproducts against N. gonorrhoeae.

No association between gender inequality and peak HIV prevalence in developing countries - an ecological study

The prevalence of both gender inequality and HIV prevalence vary considerably both within all developing countries and within those in sub-Saharan Africa. We test the hypothesis that the extent of gender inequality is associated with national peak HIV prevalence. Linear regression was used to test the association between national peak HIV prevalence and three markers of gender equality - the gender-related development index (GDI), the gender empowerment measure (GEM), and the gender inequality index (GII). No evidence was found of a positive relationship between gender inequality and HIV prevalence, either in the analyses of all developing countries or those limited to Africa. In the bivariate analyses limited to Africa, there was a positive association between the two measures of gender "equality" and peak HIV prevalence (GDI: coefficient 28, 95% confidence interval (CI) 9.1-46.8; GEM: coefficient 54.8, 95% CI 20.5-89.1). There was also a negative association between the marker of gender "inequality" and peak HIV prevalence (GII: coefficient -66.9, 95% CI -112.8 to -21.0). These associations all disappeared on multivariate analyses. We could not find any evidence to support the hypothesis that variations in the extent of gender inequality explain variations in HIV prevalence in developing countries.

The Prevalence of HIV by Ethnic Group Is Correlated with HSV-2 and Syphilis Prevalence in Kenya, South Africa, the United Kingdom, and the United States

Background. This paper investigates two issues: do ethnic/racial groups with high HIV prevalences also have higher prevalences of other STIs? and is HIV prevalence by ethnic group correlated with the prevalence of circumcision, concurrency, or having more than one partner in the preceding year? Methods. We used Spearman's correlation to estimate the association between the prevalence of HIV per ethnic/racial group and HSV-2, syphilis, symptoms of an STI, having more than one partner in the past year, concurrency, and circumcision in Kenya, South Africa, the United Kingdom, and the United States. Results. We found that in each country HSV-2, syphilis, and symptomatic STIs were positively correlated with HIV prevalence (HSV-2: Kenya rho = 0.50, P = 0.207; South Africa rho-1, P = 0.000; USA rho-1, P = 0.000, Syphilis: Kenya rho = 0.33, P = 0.420; South Africa rho-1, P = 0.000; USA rho-1, P = 0.000, and STI symptoms: Kenya rho = 0.92, P = 0.001; South Africa rho-1, P = 0.000; UK rho = 0.87, P = 0.058; USA rho-1, P = 0.000). The prevalence of circumcision was only negatively associated with HIV prevalence in Kenya. Both having more than one partner in the previous year and concurrency were positively associated with HIV prevalence in all countries (concurrency: Kenya rho = 0.79, P = 0.036; South Africa rho-1, P = 0.000; UK 0.87, P = 0.058; USA rho-1, P = 0.000 and multiple partners: Kenya rho = 0.82, P = 0.023; South Africa rho-1, P = 0.000; UK rho = 0.87, P = 0.058; USA rho-1, P = 0.000). Not all associations were statistically significant. Conclusion. Further attention needs to be directed to what determines higher rates of partner change and concurrency in communities with high STI prevalence.

The changing relationship between bacterial STIs and HIV prevalence in South Africa - an ecological study

Prevalence estimates of various bacterial sexually transmitted infections in South Africa have declined considerably since the mid-1990s. Syphilis among pregnant women, for example, declined from 10.8% in 1998 to 2.8% in 2001. We used Pearson's correlation coefficients to estimate the association between the prevalence of syphilis/male urethral discharge/male genital ulcers and the peak HIV prevalence at a district and provincial level in the early and late phases of the HIV epidemic in South Africa. Prevalence estimates of syphilis, male urethral discharge and male genital ulcers during the period preceding the peak HIV prevalence were all positively correlated with the peak HIV prevalence at a provincial level (Pearson's correlation coefficient [r] = 0.83, p = 0.006; r = 0.66, p = 0.052; r = 0.79, 0.011, respectively). These relationships all switched to a negative association later in the HIV epidemic at a provincial level (r = -0.53, p = 0.14; r = -0.73, p = 0.130; r = -0.54, p = 0.027, respectively). AIDS mortality may have played an important role in the decline of bacterial sexually transmitted infections such as syphilis in this region. Consequently, the relatively recent scale-up of antiretroviral therapy may result in a resurgence of syphilis and other sexually transmitted infections as observed in high-income countries.