Are Treponema pallidum specific rapid and point-of-care tests for syphilis accurate enough for screening in resource limited settings? Evidence from a meta-analysis

[Incidence of congenital syphilis and factors associated with vertical transmission: data from the Birth in Brazil study]

The objectives were to estimate incidence of congenital syphilis and verify factors associated with vertical transmission. A national hospital-based study was performed in 2011-2012 with 23,894 postpartum women using an in-hospital interview and data from patient charts and prenatal cards. Univariate logistic regression was performed to verify factors associated with congenital syphilis. Estimated incidence of congenital syphilis was 3.51 per 1,000 live births (95%CI: 2.29-5.37) and vertical transmission rate was 34.3% (95%CI: 24.7-45.4). Congenital syphilis was associated with lower maternal schooling, black skin color, higher rate of risk factors for prematurity, late initiation of prenatal care, fewer prenatal visits, and lower rate of prenatal serological testing. Fetal mortality was six times higher in congenital syphilis, and newborns with congenital syphilis showed higher hospital admission rates. Congenital syphilis is a persistent public health problem in Brazil and is associated with greater social vulnerability and gaps in prenatal care.

On-site test to detect syphilis in pregnancy: a systematic review of test accuracy studies

BACKGROUND

Syphilis in pregnancy can lead to fetal and neonatal death or congenital anomalies. Accurate on-site tests are an essential part of effective prevention of mother-to-child transmission of the disease.

OBJECTIVE

This systematic review assessed the accuracy of on-site tests to detect infection with Treponema pallidum in pregnant women.

SEARCH STRATEGY

Major databases were searched from inception to January 2016 using terms: 'pregnancy', 'antenatal', 'syphilis', 'Treponema pallidum' with their variations, and the search limit for the relevant study design.

SELECTION CRITERIA

We included studies that used dual reference standard (non-treponemal and treponemal tests) to detected syphilis in pregnancy.

DATA COLLECTION AND ANALYSIS

Extracted accuracy data were tabulated and pooled using hierarchical, bivariate random effects model.

MAIN RESULTS

Seven studies (combined sample 17 546) reporting the accuracy of four on-site tests met the eligibility criteria. On average, Determine™ and SD BioLine Syphilis 3.0 had the highest sensitivity of all the evaluated tests: 0.83 (95% CI 0.58, 0.98) and 0.86 (95% CI 0.82, 0.89), respectively, with a high specificity 0.96 (95% CI 0.89, 1.00) and 0.99 (95% CI 0.94, 1.00), respectively. The Qualitative Rapid Plasma Reagin card commonly used in clinical practice had a pooled sensitivity of 0.70 (95% CI 0.54, 0.88) and specificity of 0.97 (95% CI 0.96, 0.99).

CONCLUSION

Immunochromatographic tests such as Determine™ and SD BioLine Syphilis 3.0 seem to be acceptable options in antenatal testing for syphilis, especially in resource-limited settings. Future research should seek more evidence to strengthen this claim.

TWEETABLE ABSTRACT

On-site test to detect syphilis-options during antenatal care.

The introduction of syphilis point of care tests in resource limited settings

INTRODUCTION

Syphilis remains an important and preventable cause of stillbirth and neonatal mortality. About 1 million women with active syphilis become pregnant each year. Without treatment, 25% of them will deliver a stillborn baby and 33% a low birth weight baby with an increased chance of dying in the first month of life. Adverse pregnancy outcomes due to syphilis can be prevented by screening pregnant women, and treating those who test positive with a single dose of penicillin before 28 weeks' gestation. Areas covered: This manuscript covers the impact of syphilis on pregnancy outcome, the diagnosis of syphilis, with a special focus on point of care (POC) tests, and challenges to the introduction of POC tests, and their potential impact on the control and prevention of syphilis in resource limited settings. Expert commentary: POC tests for syphilis are available which meet the ASSURED criteria, and could make syphilis screening accessible to all women anywhere in the world who attend an antenatal clinic. High quality dual POC tests for HIV and syphilis could ensure that well-funded programmes for the prevention of mother to child transmission of HIV can contribute towards increased coverage of antenatal syphilis screening, and prevent more than 300,000 adverse pregnancy outcomes due to syphilis annually. Alongside investment to increase availability of syphilis POC tests, operational research is needed to understand how best to improve screening of pregnant women and to translate test availability into improved pregnancy outcomes.

Rapid diagnosis in serology

Serological diagnosis of acute phase infections implies the detection of IgM specific response, an effective marker of primary infection, but with less clinical significance in reactivations or reinfections. The aim of this article is to provide an updated view of the rapid diagnosis in serology by detecting the IgM isotype and reviewing its applications and limitations. Point-of-care (PoC) tests are analyzed. PoC tests are used in geographical areas where traditional tests are not available, as well as in other circumstances where their use brings the diagnosis directly to the target population. Likewise, their use reduces the response time between taking the sample and the diagnosis, making it easier to make clinical decisions. PoC assays have proven cost-effective, especially in preventing vertical transmission of syphilis and HIV infection.

Assessment of Two Rapid Assays for Diagnostic Capability to Accurately Identify Infection by Treponema pallidum

BACKGROUND

Rapid, point-of-care tests that accurately identify syphilis are gaining popularity and offer several advantages over classic tests.

METHODS

The SD Bioline Syphilis 3.0 and the Chembio DPP Syphilis Screen and Confirm Assay (CB) were assessed using 1283 samples that had been characterized by reference tests. The challenge samples included 5 commercial panels (seroconversion, mixed-titer), archived samples, fresh samples, and a dilution series. Both tests detect specific anti-treponemal antibodies, and the CB additionally detects antibodies to a non-treponemal (NT) component. The evaluation was used to determine performance indices and compare with those cited by the manufacturers.

RESULTS

When assessing reactivity to treponemal, the sensitivities for the 2 tests were 98.3% and 93.2%, with specificities of 100% and 99.4%, respectively. For both tests, precision, whole blood testing, and high-temperature testing produced perfect results, and there were no invalid results. Comparisons of 2 different lots of each test indicated excellent concordance (100% and 99.5%), and reproducibility was 100% and 98.0%, respectively. For the CB, the sensitivity for the NT component was between 65.3% and 80.9%, but increased to 98.5% with samples having a rapid plasma regain (RPR) titer of ≥8. The specificity for NT was found to be 100%, and the reading of results visually and when using a battery-operated reader indicated a concordance for all challenges of 95%-100%.

CONCLUSIONS

Both rapid tests produced impressive results for the detection of antibodies to treponemal for all challenges and exceeded, met, or closely approached the performance characteristics as cited by the manufacturers.

The Distribution of Syphilis Among Inpatients in Wenzhou, China: A Hospital Based Study

BACKGROUND

The high prevalence of syphilis among inpatients is an important concern in clinical settings. Thus, a better understanding of the serological test would be valuable.

OBJECTIVES

We analyzed the serological test results for syphilis among the inpatients in Wenzhou central hospital, China, to estimate the distribution of syphilis this Chinese population.

PATIENTS AND METHODS

The blood samples of 81946 inpatients at the hospital from January 2010 to December 2012 were collected and retrospectively analyzed. Syphilis testing was conducted using a Treponema pallidum enzyme-linked immunosorbent assay (TP-ELISA) and a TP particle agglutination (TPPA) assay. A toluidine red unheated serum test (TRUST) was then used to determine the titer of TP antibody in the TP- ELISA-positive samples.

RESULTS

In total, 1618 of the 81946 inpatients showed positive syphilis serology; the positive rates in 2010, 2011, and 2012 were 2.27%, 1.58%, and 2.11%, respectively. Males had a significantly higher positive rate when compared to females. Surprisingly, the highest positive rate was observed among patients older than 80 years, followed by patients younger than 19 years, while patients aged 20 - 39 years had the lowest positive rate. The TRUST titer of most TP-positive cases was less than 1:8. Patients aged 20 - 39 years showed the highest percentage of TRUST titer values ≥ 1:8, while patients older than 80 years showed the lowest percentage; the differences between these two groups were statistically significant.

CONCLUSIONS

The serological characteristics of syphilis varied with gender and age. Syphilis screening and control should be conducted for young patients and pregnant women, but special attention should also be paid to elderly inpatients. The TRUST assay is better used in syphilis screening and for judgment of curative effects, but the diagnosis needs specific methods, such as the TP-ELISA and the TPPA test.

Estimating the Public Health Burden Associated With Adverse Pregnancy Outcomes Resulting From Syphilis Infection Across 43 Countries in Sub-Saharan Africa

BACKGROUND

Untreated syphilis in pregnancy is associated with adverse clinical outcomes to the infant. The study aimed to estimate the public health burden resulting from adverse pregnancy outcomes due to syphilis infection among pregnant women not screened for syphilis in 43 countries in sub-Saharan Africa.

METHODS

Estimated country-specific incidence of syphilis was generated from annual number of live births, the proportion of women with at least 1 antenatal care (ANC) visit, the syphilis prevalence rate, and the proportion of women screened for syphilis during ANC.Adverse pregnancy outcome data (stillbirth, neonatal death, low birth weight, and congenital syphilis) were obtained from published sources. Disability-adjusted life-year (DALY) estimates were calculated using undiscounted local life expectancy, the neonatal standard loss function, and relevant disability weights. The model assessed the potential impact of raising ANC coverage to at least 95% and syphilis screening to at least 95% (World Health Organization targets).

RESULTS

For all 43 sub-Saharan Africa countries, the estimated incidence of adverse pregnancy outcomes was 205,901 (95% confidence interval [CI], 113,256-383,051) per year, including stillbirth (88,376 [95% CI, 60,854-121,713]), neonatal death (34,959 [95% CI, 23,330-50,076]), low birth weight (22,483 [95% CI, 0-98,847]), and congenital syphilis (60,084 [95% CI, 29,073-112,414]), resulting in approximately 12.5 million DALYs. Countries with the greatest burden are (in DALYs, millions) Democratic Republic of the Congo (1.809), Nigeria (1.598), Ethiopia (1.466), and Tanzania (0.961). Attaining World Health Organization targets could reduce the burden by 8.5 million DALYs.

CONCLUSIONS

Substantial infant mortality and morbidity results from maternal syphilis infection concentrated in countries with low access to ANC or low rates of syphilis screening.

Metaanalysis of the Performance of a Combined Treponemal and Nontreponemal Rapid Diagnostic Test for Syphilis and Yaws

A combined treponemal and nontreponemal rapid diagnostic test was found to have good sensitivity and specificity for both syphilis and yaws. The performance of both the treponemal and nontreponemal test components was strongly associated with the rapid plasma reagin titer.

Background. The human treponematoses are important causes of disease. Mother-to-child transmission of syphilis remains a major cause of stillbirth and neonatal death. There are also almost 100 000 cases of endemic treponemal disease reported annually, predominantly yaws. Rapid diagnostic tests (RDTs) would improve access to screening for these diseases. Most RDTs cannot distinguish current and previous infection. The Dual Path Platform (DPP) Syphilis Screen & Confirm test includes both a treponemal (T1) and nontreponemal (T2) component and may improve the accuracy of diagnosis.

Methods. We conducted a metaanalysis of published and unpublished evaluations of the DPP-RDT for the diagnosis of syphilis and yaws. We calculated the sensitivity, specificity, and overall agreement of the test compared with reference laboratory tests.

Results. Nine evaluations, including 7267 tests, were included. Sensitivity was higher in patients with higher titer rapid plasma reagin (≥1:16) for both the T1 (98.2% vs 90.1%, P < .0001) and the T2 component (98.2% vs 80.6%, P < .0001). Overall agreement between the DPP test and reference serology was 85.2% (84.4%–86.1%). Agreement was highest for high-titer active infection and lowest for past infection.

Conclusions. The RDT has good sensitivity and specificity of the treponemal and nontreponemal components both in cases of suspected syphilis and yaws, although the sensitivity is decreased at lower antibody titers.

Secondary syphilis in the oral cavity and the role of the dental surgeon in STD prevention, diagnosis and treatment: a case series study

Syphilis is an infectious disease caused by the bacterium Treponema pallidum. Syphilis has three clinical stages and may present various oral manifestations, mainly at the secondary stage. The disease mimics other more common oral mucosa lesions, going undiagnosed and with no proper treatment. Despite the advancements in medicine toward prevention, diagnosis, and treatment syphilis remains a public health problem worldwide. In this sense, dental surgeons should be able to identify the most common manifestations of the disease in the oral cavity, pointing to the role of this professional in prevention and diagnosis. This study describes a case series of seven patients with secondary syphilis presenting different oral manifestations.

Field evaluation of Standard Diagnostics' Bioline HIV/Syphilis Duo test among female sex workers in Johannesburg, South Africa

BACKGROUND

Point-of-care tests provide immediate results with the opportunity for same-day interventions with improved public health outcomes. A dual HIV/syphilis test enables early treatment of both diseases.

METHODS

We conducted a field evaluation of the Standard Diagnostics' SD Bioline HIV/Syphilis Duo test (SD Bioline) among female sex workers. SD Bioline was conducted on finger-prick blood according to manufacturer's instructions and compared with (i) Genscreen HIV1/2 (third generation) and Vironostika Ag/Ab (fourth generation) assays for HIV, and (ii) Treponema pallidum particle agglutination (TPPA) and rapid plasma reagin (RPR) assays for syphilis. A negative TPPA test was considered negative, a TPPA-confirmed RPR titre ≤1:4 as past infection and a TPPA-confirmed RPR titre ≥1:8 as active syphilis. Sensitivity, specificity, positive and negative predictive values were calculated.

RESULTS

Of 263 women recruited, 14 (5.3%) declined an HIV test. Among the remaining 249 women, 187 (75.1%) were HIV positive, 51 (20.5%) had syphilis antibodies with seven (2.8%) active infections. For HIV, the sensitivity and specificity were 98.9% (95% CI 95.8% to 99.8%) and 100% (95% CI 92.7% to 100%). For syphilis, the sensitivity and specificity were 66.7% (95% CI 52.0% to 78.9%) and 98.0% (95% CI 94.5% to 99.3%). Sera with high TPPA titres were more likely to test positive.

CONCLUSIONS

In field conditions, while the SD Bioline test has high sensitivity and specificity for HIV and high specificity for syphilis, the test has lower sensitivity for syphilis than reported from laboratory evaluations. As the dual test detects only two thirds of syphilis cases, it should only be used in areas with weak screening programmes.

Efforts in blood safety: Integrated approach for serological diagnosis of syphilis

Recent efforts in transfusion medicine are focused on improving blood safety as well as establishing effective and efficient diagnostic algorithms for donor screening. To date, syphilis is a transfusion-transmitted infection re-emerged in many countries as a public health threat especially among populations at specific risk. This task requires new diagnostic tools and hemovigilance programs. The current diagnostic methodologies are debated, since presenting limitations and unresolved issues with special regard to the clinical interpretation of serological patterns, especially in asymptomatic patients and in blood donors. Furthermore, the switch from the traditional to alternative diagnostic algorithms underlines the lack of a gold standard, which has not been supported by shared guidelines. Besides, a lot of ongoing clinical trials on the performance of diagnostic assays, on the serological response associated with different pharmacological treatments, as well as on the prevention programs are currently under investigation. Here, we review the recent literature about the diagnosis of syphilis especially for low-risk populations proposing the adoption of an algorithm for blood donor screening that should satisfy the need of increasing safety for transfusion-transmitted infections in the modern blood transfusion centers.

Current Perspectives on Prevention of Mother-to-Child Transmission of Syphilis

This article aims to provide an update on the prevention of mother-to-child transmission of syphilis by drawing upon some important basic concepts and reviewing the most recent literature on the diagnosis and treatment of syphilis in pregnancy. New technologies, such as automated and point-of-care immunologic tests, are shifting some paradigms, which will certainly be further investigated in the forthcoming years. This is the time to carefully evaluate traditional as well as new strategies to prevent congenital syphilis. Adverse outcomes of mother-to-child transmission of syphilis can be prevented with antenatal screening and penicillin therapy, which proved to have an excellent cost-benefit ratio even in populations with a low prevalence of syphilis. However, syphilis epidemiology is influenced by socioeconomic and cultural factors, and major challenges are faced by poor and developing countries in which the severity of the problem is extremely alarming. On the other hand, the emergence of new technologies has raised doubts about the best algorithm to be used when proper laboratory resources are available. Conditions are quite heterogeneous across populations, and some procedures should not be generalized while there is no evidence that supports some changes and while in-depth studies about local conditions are not conducted. Official organizations need to be alert in order to avoid isolated decisions and ensure that evidence-based guidelines be used in the management of syphilis in pregnancy.

Rapid Syphilis Testing Is Cost-Effective Even in Low-Prevalence Settings: The CISNE-PERU Experience

Studies have addressed cost-effectiveness of syphilis testing of pregnant women in high-prevalence settings. This study compares costs of rapid syphilis testing (RST) with laboratory-based rapid plasma reagin (RPR) tests in low-prevalence settings in Peru. The RST was introduced in a tertiary-level maternity hospital and in the Ventanilla Network of primary health centers, where syphilis prevalence is approximately 1%. The costs per woman tested and treated with RST at the hospital were $2.70 and $369 respectively compared with $3.60 and $740 for RPR. For the Ventanilla Network the costs per woman tested and treated with RST were $3.19 and $295 respectively compared with $5.55 and $1454 for RPR. The cost per DALY averted using RST was $46 vs. $109 for RPR. RST showed lower costs compared to the WHO standard costs per DALY ($64). Findings suggest syphilis screening with RST is cost-effective in low-prevalence settings.

Characterization and six-month follow-up on a cohort of newborns with congenital syphilis

INTRODUCTION

Congenital syphilis is a preventable disease. However, the incidence in Colombia has increased and reached the figure of 3.28 cases per 1,000 live births in 2011. 

OBJECTIVE

To characterize newborns with congenital syphilis and describe follow-up over 6 months following their diagnosis and treatment. 

MATERIALS AND METHODS

Between August, 2011, and February, 2012, in Hospital La Victoria, sede Instituto Materno Infantil, newborns with congenital syphilis were identified and treated. Clinical and laboratory follow-up was carried out for six months until it was determined that the disease was cured. The analyzed variables included patients' clinical and laboratory characteristics. 

RESULTS

In this period, we identified 29 cases that met the criteria of congenital syphilis, with a frequency in the institution of one case per 69 births. There was one stillbirth and one neonatal death, four were premature, and five had growth restriction. Of the 28 live births, 15 were asymptomatic. There were two cases with neurosyphilis, representing 15% of symptomatic newborns. Follow-up was done on 18 out of 27 children (66.6%), including most symptomatic cases and the two cases of neurosyphilis. All cases showed the expected decrease in VDRL titers without clinical sequelae, meeting the criteria of being cured. 

CONCLUSIONS

A high incidence of the disease, failure to prevent it, varied expression in its presentation, and the effectiveness of treatment in the neonatal period were evidenced in this study.

Multiplexed testing for HIV and related bacterial and viral co-infections at the point-of-care: quo vadis?

Recently, there has been a paradigm shift toward an understanding of the need to screen select sub-populations for several sexually transmitted and blood-borne infections simultaneously, at one time with various rapid point-of-care (POC) technologies, rather than one infection at a time. This is an encouraging and promising change, however many contextual factors need to be considered before implementing such technologies. In this editorial, we highlight some challenges, issues and concerns regarding implementation, integration, and uptake of these technologies across global settings. However, careful planning and well thought out implementation plan that include investments in training health care professionals, improving test and treat algorithms, rapid protocols on communicating actionable results to providers, and timely action, will bring about the desired impact in patient's lives. This is especially true in settings where they stand to achieve the maximum desired public health and social impact.

A smartphone dongle for diagnosis of infectious diseases at the point of care

This work demonstrates that a full laboratory-quality immunoassay can be run on a smartphone accessory. This low-cost dongle replicates all mechanical, optical, and electronic functions of a laboratory-based enzyme-linked immunosorbent assay (ELISA) without requiring any stored energy; all necessary power is drawn from a smartphone. Rwandan health care workers used the dongle to test whole blood obtained via fingerprick from 96 patients enrolling into care at prevention of mother-to-child transmission clinics or voluntary counseling and testing centers. The dongle performed a triplexed immunoassay not currently available in a single test format: HIV antibody, treponemal-specific antibody for syphilis, and nontreponemal antibody for active syphilis infection. In a blinded experiment, health care workers obtained diagnostic results in 15 min from our triplex test that rivaled the gold standard of laboratory-based HIV ELISA and rapid plasma reagin (a screening test for syphilis), with sensitivity of 92 to 100% and specificity of 79 to 100%, consistent with needs of current clinical algorithms. Patient preference for the dongle was 97% compared to laboratory-based tests, with most pointing to the convenience of obtaining quick results with a single fingerprick. This work suggests that coupling microfluidics with recent advances in consumer electronics can make certain laboratory-based diagnostics accessible to almost any population with access to smartphones.

Community-based sexually transmitted infection screening and increased detection of pharyngeal and urogenital Chlamydia trachomatis and Neisseria gonorrhoeae infections in female sex workers in Hong Kong

Chlamydia and gonorrhea remain the most commonly sexually transmitted infections detected in female sex worker. Although the prevalence of urogenital Chlamydia trachomatis is increasing, pharyngeal gonococcal infection is likely to be overlooked in Hong Kong.

Background

Female sex workers (FSWs) are vulnerable to sexually transmitted infections (STIs) and are one of the key populations being infected most by Chlamydia trachomatis and Neisseria gonorrhoeae infections. In Hong Kong, limited data on the burden of chlamydial and gonococcal infections exist because regular screenings are not offered. This study aimed to investigate the prevalence of C. trachomatis and N. gonorrhoeae in FSWs and to assess predictors associated with unprotected fellatio.

Methods

A cross-sectional study was conduct on 340 FSWs attending a community organization for HIV/STI screening, and a questionnaire addressing sociodemographic and behavioral characteristics was administered to all FSWs.

Results

The prevalence of syphilis infection was 2.1%, and none was tested positive for HIV. The positivity for pharyngeal C. trachomatis and N. gonorrhoeae was 3.2% and 4.4%, respectively, whereas that for urogenital chlamydial and gonococcal infection was 10.6% and 0.9%, respectively. Of 313 FSWs offering fellatio, having unprotected fellatio with clients was significantly associated with the perceived low risk of contracting STI via fellatio (adjusted odds ratio [OR], 1.88), working in clubs (adjusted OR, 11.14), working on streets (adjusted OR, 3.28), recently started working in the sex industry for 1 year or less (adjusted OR, 3.05), and reporting group sex in the previous year (adjusted OR, 11.03).

Conclusions

The prevalence of HIV and syphilis infection remains low. This study reveals a relatively high prevalence of N. gonorrhoeae detected mostly in the pharynx. Offering pharyngeal screening for STI would facilitate early diagnosis and treatment of gonococcal infection in FSWs in Hong Kong.

Neurosyphilis in psychiatric practice: a case-based discussion of clinical evaluation and diagnosis

OBJECTIVE

Neurosyphilis can present with a wide range of neuropsychiatric symptoms. Hence, psychiatrists need to be familiar with tests for syphilis screening and how to interpret syphilis serologic tests.

METHODS

We present four cases of patients with positive syphilis tests encountered in a psychiatric hospital.

RESULTS

Two cases were treated for neurosyphilis, while the other two cases did not have active syphilis infection despite positive results.

CONCLUSION

We thus highlight the challenges encountered by psychiatrists in screening for and diagnosing cases of neurosyphilis.

Implementation of Point-of-Care Diagnostics Leads to Variable Uptake of Syphilis, Anemia and CD4+ T-Cell Count Testing in Rural Maternal and Child Health Clinics

INTRODUCTION

Anemia, syphilis and HIV are high burden diseases among pregnant women in sub-Saharan Africa. A quasi-experimental study was conducted in four health facilities in Southern Mozambique to evaluate the effect of point-of-care technologies for hemoglobin quantification, syphilis testing and CD4+ T-cell enumeration performed within maternal and child health services on testing and treatment coverage, and assessing acceptability by health workers.

METHODS

Demographic and testing data on women attending first antenatal care services were extracted from existing records, before (2011; n = 865) and after (2012; n = 808) introduction of point-of-care testing. Study outcomes per health facility were compared using z-tests (categorical variables) and Wilcoxon rank-sum test (continuous variables), while inverse variance weights were used to adjust for possible cluster effects in the pooled analysis. A structured acceptability-assessment interview was conducted with health workers before (n = 22) and after (n = 19).

RESULTS

After implementation of point-of-care testing, there was no significant change in uptake of overall hemoglobin screening (67.9% to 83.0%; p = 0.229), syphilis screening (80.8% to 87.0%; p = 0.282) and CD4+ T-cell testing (84.9% to 83.5%; p = 0.930). Initiation of antiretroviral therapy for treatment eligible women was similar in the weighted analysis before and after, with variability among the sites. Time from HIV diagnosis to treatment initiation decreased (median of 44 days to 17 days; p<0.0001). A generally good acceptability for point-of-care testing was seen among health workers.

CONCLUSIONS

Point-of-care CD4+ T-cell enumeration resulted in a decreased time to initiation of antiretroviral therapy among treatment eligible women, without significant increase in testing coverage. Overall hemoglobin and syphilis screening increased. Despite the perception that point-of-care technologies increase access to health services, the variability in results indicate the potential for detrimental effects in some settings. Local context needs to be considered and services restructured to accommodate innovative technologies in order to improve service delivery to expectant mothers.

Diagnostic accuracy of rapid tests for sexually transmitted infections in symptomatic women

OBJECTIVE

To determine the diagnostic accuracy of tests developed for use at the point of care for Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and syphilis in women having symptoms of lower urinary tract infection.

METHODS

Cross-sectional study involving sexually active 14-49-year-old women with lower urinary tract infection symptoms consulting during 2010 at a private health clinic and at two public hospitals in Bogotá, Colombia. Pregnant women, those with a previous hysterectomy or those who received antibiotics during the previous 7 days were excluded. Sequential sampling was used; sample size: 1500 women. The ACON NG and CT duo test combo and the ACON individual test plates for NG and separately for CT were used. The QuickVue Chlamydia rapid test (RT) was also used. All of them were compared with nucleic acid amplification methods. The SD Bioline 3.0 and ACON test for syphilis were evaluated and compared with serological tests. Sensitivity and specificity were estimated.

RESULTS

CT RTs had a sensitivity that ranged between 22.7% and 37.7% and specificity between 99.3% and 100%. Sensitivity for NG with ACON Duo was 12.5% and specificity 99.8%. Tests for syphilis had a sensitivity of 91.6-100% and a specificity of 99.7-97.8%.

CONCLUSIONS

The RTs studied are not useful for screening for NG at the point of care. In case of CT a recommendation about their use in routine care should be supported by a cost-effectiveness analysis. In screening populations at high risk of sexually transmitted infections or pregnant women, the RTs for syphilis should be used.

Antenatal syphilis screening using point-of-care testing in low- and middle-income countries in Asia and Latin America: a cost-effectiveness analysis

BACKGROUND

Untreated syphilis in pregnancy is associated with adverse clinical outcomes to the infant. In low- and middle-income countries in Asia and Latin America, 20%-30% of women are not tested for syphilis during pregnancy. We evaluated the cost-effectiveness of increasing the coverage for antenatal syphilis screening in 11 Asian and 20 Latin American countries, using a point-of-care immunochromatographic strip (ICS) test.

METHODS

The decision analytical cost-effectiveness models reported incremental costs per disability-adjusted life years (DALYs) averted from the perspectives of the national health care payer. Clinical outcomes were stillbirths, neonatal deaths, and congenital syphilis. DALYs were computed using WHO disability weights. Costs included the ICS test, three injections of benzathine penicillin, and nurse wages. Country-specific inputs included the antenatal prevalence of syphilis and the proportion of women in the antenatal care setting that are screened for syphilis infection as reported in the 2014 WHO baseline report on global sexually transmitted infection surveillance. Country-specific data on the annual number of live births, proportion of women with at least one antenatal care visit, and per capita gross national income were also included in the model.

RESULTS

The incremental cost/DALY averted of syphilis screening is US$53 (range: US$10-US$332; Prob<1*per capita GDP=99.71%) in Asia and US$60 (range: US$5-US$225; Prob<1*per capita GDP=99.77%) in Latin America. Universal screening may reduce the annual number of stillbirths by 20,344 and 4,270, neonatal deaths by 8,201 and 1,721, cases of congenital syphilis by 10,952 and 2,298, and avert 925,039 and 197,454 DALYs in the aggregate Asian and Latin American panel, respectively.

CONCLUSION

Antenatal syphilis screening is highly cost-effective in all the 11 Asian and 20 Latin American countries assessed. Our findings support the decision to expand syphilis screening in countries with currently low screening rates or continue national syphilis screening programs in countries with high rates.

Evaluation of an immunochromatographic point-of-care test for the simultaneous detection of nontreponemal and treponemal antibodies in patients with syphilis

We described the evaluation of the Syphilis Screening & Confirm Assay for the simultaneous detection of nontreponemal and treponemal antibodies. A total of 248 samples were evaluated. The sensitivity of the tests was 98.8%, 99.5% and 98.9%, while specificity was 94.7%, 88.9% and 93.2%, respectively, as compared with the rapid plasma reagin, Treponema pallidum hemagglutination assay, and fluorescent treponemal antibody absorption tests.

An evaluation of a novel dual treponemal/nontreponemal point-of-care test for syphilis as a tool to distinguish active from past treated infection

BACKGROUND

Most syphilis point-of-care (POC) tests detect treponemal antibodies, which persist after successful treatment. Subsequent POC tests are positive, despite no active infection, and can lead to unnecessary treatment. We evaluated a new POC test, incorporating a nontreponemal component, to distinguish active from past infection.

METHODS

Sera stored at 2 Australian laboratories were tested with DPP Screen and Confirm Assay. Treponemal and nontreponemal test lines were compared to corresponding conventional treponemal and nontreponemal reference test results: immunoassays and rapid plasma reagin (RPR), respectively, with RPR quantification by endpoint titration. POC test outcome concordance with conventional test results was assessed according to serological and clinical categories.

RESULTS

Among 1005 serum samples tested, DPP treponemal line sensitivity was 89.8% (95% confidence interval [CI], 87.3%-91.9%) and specificity was 99.3% (95% CI, 97.0%-99.9%). DPP nontreponemal line sensitivity was 94.2% (95% CI, 91.8%-96.0%) and specificity was 62.2% (95% CI, 57.5%-66.6%). DPP test outcome (pair of test lines) was concordant with both reference test results for 94.3% of 404 high-titer infections, 90.1% of 121 low-titer infections, 27.5% of 211 past/treated infections, and 78.1% of 242 infections classified as not syphilis. Among 211 past/treated infections, 49.8% were incorrectly identified as active infection and a further 22.8% as not syphilis.

CONCLUSIONS

DPP test use would result in identification of >93% of active syphilis infections, whereas just over half of past infections would be diagnosed as past or not syphilis, avoiding unnecessary treatment compared with other POC tests. This may be at the expense of missing some active infections; thus, its potential benefits will depend on the prevalence of past vs active infection in a population.

Factors associated with failure to screen for syphilis during antenatal care in Ghana: a case control study

Background

There is little data regarding the effect of ramping up new screening interventions on their uptake by target populations into routine care services in developing countries. This study aimed to determine patient-level factors associated with failure of pregnant women to get screened for syphilis during antenatal care, in the context of a national rollout of rapid syphilis point of care tests (POCTs) in Ghana.

Methods

An unmatched 1:2 case control study conducted among women admitted for delivery in two district hospitals in the Ashanti Region of Ghana from August to October 2010, 7 to 9 months after the introduction of POCTs in the region. Cases were women who had not been screened for syphilis during antenatal care and controls were women who had been screened. Patient-reported factors for being unscreened were examined using logistic regression to obtain odds ratios (ORs) and 95% confidence intervals (CIs).

Results

160 consecutive unscreened and 327 screened women were recruited. Most women had good knowledge of syphilis (58.7% among unscreened women vs. 64.2% among screened; P = 0.24). Factors associated with failure to get screened were: attending antenatal care in a private health facility (adjusted OR, 11.09; 95% CI 5.48-22.48), previous adverse pregnancy outcome (adjusted OR, 1.98; 95% CI 1.22-3.23) and not being screened for HIV during the current pregnancy (adjusted OR, 2.78; 95% CI 1.50-5.13). The odds of being unscreened also increased with decreasing doses of intermittent preventive treatment for malaria in pregnancy received (P trend < 0.001) and decreasing education level (P trend = 0.02).

Conclusion

Significant risk factors for not being screened, following the national rollout of syphilis POCTs, related to the type of health facility where antenatal care was received and some of the women’s personal characteristics. Targeting of private medical facilities to include syphilis POCTs and support other neglected public health interventions should be a priority.

Recent trends in the serologic diagnosis of syphilis

Complexities in the diagnosis of syphilis continue to challenge clinicians. While direct tests (e.g., microscopy or PCR) are helpful in early syphilis, the mainstay of diagnosis remains serologic tests. The traditional algorithm using a nontreponemal test (NTT) followed by a treponemal test (TT) remains the standard in many parts of the world. More recently, the ability to automate the TT has led to the increasingly widespread use of reverse algorithms using treponemal enzyme immunoassays (EIAs). Rapid, point-of-care TTs are in widespread use in developing countries because of low cost, ease of use, and reasonable performance. However, none of the current diagnostic algorithms are able to distinguish current from previously treated infections. In addition, the reversal of traditional syphilis algorithms has led to uncertainty in the clinical management of patients. The interpretation of syphilis tests is further complicated by the lack of a reliable gold standard for syphilis diagnostics, and the newer tests can result in false-positive reactions similar to those seen with older tests. Little progress has been made in the area of serologic diagnostics for congenital syphilis, which requires assessment of maternal treatment and serologic response as well as clinical and laboratory investigation of the neonate for appropriate management. The diagnosis of neurosyphilis continues to require the collection of cerebrospinal fluid for a combination of NTT and TT, and, while newer treponemal EIAs look promising, more studies are needed to confirm their utility. This article reviews current tests and discusses current controversies in syphilis diagnosis, with a focus on serologic tests.

Integration of antenatal syphilis screening in an urban HIV clinic: a feasibility study

BACKGROUND

Syphilis infection during pregnancy leads to avoidable morbidity and mortality and remains a significant problem in sub-Saharan Africa. Despite global initiatives to increase the proportion of pregnant women screened, implementation has been slow. We sought to investigate the feasibility of adding syphilis screening within an integrated antenatal HIV clinic.

METHODS

Pregnant women attending the HIV antenatal clinic were sequentially enrolled and consenting participants answered a questionnaire on sexual behavior and previous pregnancies, provided sociodemographic data, and were tested using rapid plasmin reagin (RPR). If positive, participants were treated with benzathine penicillin. All were given a partner notification slip and were followed up after delivery to determine birth outcomes.

RESULTS

584 of 606 (95.7%) women approached and consented to test for syphilis. 570 women were enrolled (median age 29 (IQR 25-32) with a median (IQR) CD4 of 372 (257-569) cells/μL). Of the 5.1% (29/570) with a positive RPR, all were asymptomatic, were successfully contacted, and treated with benzathine penicillin without adverse reactions. Overall, 61 (12.1%) of the participants had an adverse birth outcome. In the bivariate analysis, only age was significantly different between those with and without a positive RPR (RR = 1.15, 95% CI 1.065-1.248; p < 0.001). Partners of only 10 (34.5%) participants returned for treatment.

CONCLUSIONS

Structural interventions such as opt-out testing for syphilis within integrated HIV-antenatal care clinics are feasible and capitalize on the excellent care programs that have already been established for HIV care. Novel approaches are required for partner notification.

A review of recent advances in rapid point-of-care tests for syphilis

Syphilis is a curable disease, yet over 10million people worldwide are infected with syphilis each year. Syphilis case finding and subsequent treatment are key steps in syphilis control and prevention efforts. The advent of rapid point-of-care tests - which require minimal equipment, are easy to perform and are relatively low cost - have the potential to improve syphilis control by allowing for more widespread testing in clinical and non-clinical settings. However, strategies to maximise the potential public health impact of those tests are needed, and those include regulatory oversight, effective supply-chain management and quality assurance systems.

Will a quadruple multiplexed point-of-care screening strategy for HIV-related co-infections be feasible and impact detection of new co-infections in at-risk populations? Results from cross-sectional studies

OBJECTIVES

Multiplexed point-of-care (POC) devices can rapidly screen for HIV-related co-infections (eg, hepatitis C (HCV), hepatitis B (HBV), syphilis) in one patient visit, but global evidence for this approach remains limited. This study aimed to evaluate a multiplex POC testing strategy to expedite screening for HIV-related co-infections in at-risk populations.

METHODS

A multiplex strategy was developed with two subsequent versions of an investigational device Miriad. It was evaluated in two non-comparable settings and populations in two countries for feasibility of conduct, detection of new infections, preference and accuracy. Version 1 was evaluated in 375 sexually transmitted disease clinic attendees in Mumbai, India; version 2 was evaluated in 119 injection drug users in Montreal, Canada.

RESULTS

Feasibility (completion rate) of the multiplex strategy was high (86.1% Mumbai; 92.4% Montreal). A total of 170 new infections were detected in Mumbai (56 HIV, 75 HBV, 37 syphilis, 2 HCV) versus 2 in Montreal. Preference was 60% in Mumbai and 97% in Montreal. Miriad version 1 specificities were high: HIV 99.7% (98.3% to 100%), HBV 99.3% (97.6% to 99.9%), HCV 99.7% (98.5% to 99.9%), syphilis 85.2% (80.9% to 88.8%); sensitivities were as follows: HIV 100% (94.8% to 100%), HBV 13.3% (6.6% to 23.2%), HCV 50% (1.3% to 98.7%), syphilis 86.1% (70.5% to 95.3%). With version 2, specificities improved: HIV 100% (97.2% to 100%), HBV 100% (97.3% to 100%), HCV 85.3% (73.8% to 93.0%), syphilis 98.1% (93.3% to 99.8%); sensitivities were: HIV 100% (47.3% to 100%), HCV 80.4% (66.1% to 90.6%), syphilis 100% (22.4% to 100%).

CONCLUSIONS

A quad multiplex POC strategy for HIV and co-infections was feasible to operationalise and preferred by patients in both settings. Many new infections were identified in Mumbai and accuracy improved with version 2 of the assay. Such a strategy will help expedite screening for co-infections, particularly where baseline screening is low. These findings are valuable to practitioners, researchers, policymakers and funders involved in initiatives for all four diseases with implications for scale-up.

Sensitivity and specificity of point-of-care rapid combination syphilis-HIV-HCV tests

Background

New rapid point-of-care (POC) tests are being developed that would offer the opportunity to increase screening and treatment of several infections, including syphilis. This study evaluated three of these new rapid POC tests at a site in Southern California.

Methods

Participants were recruited from a testing center in Long Beach, California. A whole blood specimen was used to evaluate the performance of the Dual Path Platform (DPP) Syphilis Screen & Confirm, DPP HIV-Syphilis, and DPP HIV-HCV-Syphilis rapid tests. The gold-standard comparisons were Treponema pallidum passive particle agglutination (TPPA), rapid plasma reagin (RPR), HCV enzyme immunoassay (EIA), and HIV-1/2 EIA.

Results

A total of 948 whole blood specimens were analyzed in this study. The sensitivity of the HIV tests ranged from 95.7–100% and the specificity was 99.7–100%. The sensitivity and specificity of the HCV test were 91.8% and 99.3%, respectively. The treponemal-test sensitivity when compared to TPPA ranged from 44.0–52.7% and specificity was 98.7–99.6%. The non-treponemal test sensitivity and specificity when compared to RPR was 47.8% and 98.9%, respectively. The sensitivity of the Screen & Confirm test improved to 90.0% when cases who were both treponemal and nontreponemal positive were compared to TPPA+/RPR ≥1∶8.

Conclusions

The HIV and HCV on the multi-infection tests showed good performance, but the treponemal and nontreponemal tests had low sensitivity. These results could be due to a low prevalence of active syphilis in the sample population because the sensitivity improved when the gold standard was limited to those more likely to be active cases. Further evaluation of the new syphilis POC tests is required before implementation into testing programs.

Laboratory evaluation of three rapid diagnostic tests for dual detection of HIV and Treponema pallidum antibodies

The performance of three research-use-only, dual HIV and syphilis rapid diagnostic tests (RDTs) was evaluated for 150 patient serum samples and compared to reference HIV and Treponema pallidum antibody detection methods. The RDTs performed comparably, with sensitivities of 93 to 99% and specificities of 97 to 100%. The kappa statistic between the RDTs was 0.95.

Screening tests: a review with examples

Screening tests are widely used in medicine to assess the likelihood that members of a defined population have a particular disease. This article presents an overview of such tests including the definitions of key technical (sensitivity and specificity) and population characteristics necessary to assess the benefits and limitations of such tests. Several examples are used to illustrate calculations, including the characteristics of low dose computed tomography as a lung cancer screen, choice of an optimal PSA cutoff and selection of the population to undergo mammography. The importance of careful consideration of the consequences of both false positives and negatives is highlighted. Receiver operating characteristic curves are explained as is the need to carefully select the population group to be tested.

Audit of antenatal screening for syphilis and HIV in migrant and refugee women on the Thai-Myanmar border: a descriptive study

Objective: The antenatal prevalence of syphilis and HIV/AIDS in migrants and refugees is poorly documented. The aim of this study was to audit the first year of routine syphilis screening in the same population and reassess the trends in HIV rates.

Methods: From August 2012 to July 2013, 3600 pregnant women were screened for HIV (ELISA) and syphilis (VDRL with TPHA confirmation) at clinics along the Thai-Myanmar border.

Results: Seroprevalence for HIV 0.47% (95% CI 0.30-0.76) (17/3,599), and syphilis 0.39% (95% CI 0.23-0.65) (14/3,592), were low. Syphilis was significantly lower in refugees (0.07% 95% CI 0.01-0.38) (1/1,469), than in migrants (0.61% 95% CI 0.36-1.04) (13/2,123). The three active (VDRL≥1:8 and TPHA reactive) syphilis cases with VDRL titres of 1:32 were easy to counsel and treat. Women with low VDRL titres (>75% were < 1:8) and TPHA reactive results, in the absence of symptoms and both the woman and her husband having only one sexual partner in their lifetime, and the inability to determine the true cause of the positive results presented ethical difficulties for counsellors.

Conclusion: As HIV and syphilis testing becomes available in more and more settings, the potential impact of false positive results should be considered, especially in populations with low prevalence for these diseases. This uncertainty must be considered in order to counsel patients and partners accurately and safely about the results of these tests, without exposing women to increased risk for abuse or abandonment. Our findings highlight the complexities of counselling patients about these tests and the global need for more conclusive syphilis testing strategies.

Poor Reporting of Outcomes Beyond Accuracy in Point-of-Care Tests for Syphilis: A Call for a Framework

Background. Point-of-care (POC) diagnostics for syphilis can contribute to epidemic control by offering a timely knowledge of serostatus. Although accuracy data on POC syphilis tests have been widely published, few studies have evaluated broader outcomes beyond accuracy that impact patients and health systems. We comprehensively reviewed evidence and reporting of these implementation research outcomes (IROs), and proposed a framework to improve their quality. Methods. Three reviewers systematically searched 6 electronic databases from 1980 to 2014 for syphilis POC studies reporting IROs. Data were abstracted and findings synthesised narratively. Results. Of 71 studies identified, 38 documented IROs. IROs were subclassified into preference (7), acceptability (15), feasibility (15), barriers and challenges (15), impact (13), and prevalence (23). Using our framework and definitions, a pattern of incomplete documentation, inconsistent definitions, and lack of clarity was identified across all IROs. Conclusion. Although POC screening tests for syphilis were generally favourably evaluated across a range of outcomes, the quality of evidence was compromised by inconsistent definitions, poor methodology, and documentation of outcomes. A framework for standardized reporting of outcomes beyond accuracy was proposed and considered a necessary first step towards an effective implementation of these metrics in POC diagnostics research.

A laboratory-based evaluation of four rapid point-of-care tests for syphilis

Background

Syphilis point-of-care tests may reduce morbidity and ongoing transmission by increasing the proportion of people rapidly treated. Syphilis stage and co-infection with HIV may influence test performance. We evaluated four commercially available syphilis point-of-care devices in a head-to-head comparison using sera from laboratories in Australia.

Methods

Point-of-care tests were evaluated using sera stored at Sydney and Melbourne laboratories. Sensitivity and specificity were calculated by standard methods, comparing point-of-care results to treponemal immunoassay (IA) reference test results. Additional analyses by clinical syphilis stage, HIV status, and non-treponemal antibody titre were performed. Non-overlapping 95% confidence intervals (CI) were considered statistically significant differences in estimates.

Results

In total 1203 specimens were tested (736 IA-reactive, 467 IA-nonreactive). Point-of-care test sensitivities were: Determine 97.3%(95%CI:95.8–98.3), Onsite 92.5%(90.3–94.3), DPP 89.8%(87.3–91.9) and Bioline 87.8%(85.1–90.0). Specificities were: Determine 96.4%(94.1–97.8), Onsite 92.5%(90.3–94.3), DPP 98.3%(96.5–99.2), and Bioline 98.5%(96.8–99.3). Sensitivity of the Determine test was 100% for primary and 100% for secondary syphilis. The three other tests had reduced sensitivity among primary (80.4–90.2%) compared to secondary syphilis (94.3–98.6%). No significant differences in sensitivity were observed by HIV status. Test sensitivities were significantly higher among high-RPR titre (RPR≥8) (range: 94.6–99.5%) than RPR non-reactive infections (range: 76.3–92.9%).

Conclusions

The Determine test had the highest sensitivity overall. All tests were most sensitive among high-RPR titre infections. Point-of-care tests have a role in syphilis control programs however in developed countries with established laboratory infrastructures, the lower sensitivities of some tests observed in primary syphilis suggest these would need to be supplemented with additional tests among populations where syphilis incidence is high to avoid missing early syphilis cases.

Feasibility and Field Performance of a Simultaneous Syphilis and HIV Point-of-Care Test Based Screening Strategy in at Risk Populations in Edmonton, Canada

Few studies have evaluated the feasibility of delivering syphilis point-of-care (POC) testing in outreach (nonclinical) settings in resource rich countries. The objectives of the study were to evaluate the feasibility and diagnostic performance of performing both HIV and syphilis POC testing in outreach settings and to document new cases identified in the study population. 1,265 outreach testing visits were offered syphilis and HIV POC testing and 81.5% (n = 1,031) consented to testing. In our population, the SD Bioline 3.0 Syphilis Test had a sensitivity of 85.3% [CI (68.9-95.0)], specificity of 100.0% [CI (99.6-100.0)], positive predictive value (PPV) of 100.0% [CI (88.1-100.0)], and negative predictive value (NPV) of 99.5% [CI (98.9-99.8)]. Test characteristics for the INSTI HIV-1/HIV-2 Antibody Test had a 100.0% sensitivity [CI (39.8-100.00], 99.8 specificity [CI (99.3-100)], 66.7% PPV [CI (22.3-95.7)], and 100.0% NPV [CI (99.6-100.0)]. Four new cases of syphilis and four new HIV cases were diagnosed. In summary, at risk population seeking STI testing found POC tests to be acceptable, the POC tests performed well in outreach settings, and new cases of syphilis and HIV were identified and linked to treatment and care.

Diagnostic point-of-care tests in resource-limited settings

The aim of diagnostic point-of-care testing is to minimise the time to obtain a test result, thereby allowing clinicians and patients to make a quick clinical decision. Because point-of-care tests are used in resource-limited settings, the benefits need to outweigh the costs. To optimise point-of-care testing in resource-limited settings, diagnostic tests need rigorous assessments focused on relevant clinical outcomes and operational costs, which differ from assessments of conventional diagnostic tests. We reviewed published studies on point-of-care testing in resource-limited settings, and found no clearly defined metric for the clinical usefulness of point-of-care testing. Therefore, we propose a framework for the assessment of point-of-care tests, and suggest and define the term test efficacy to describe the ability of a diagnostic test to support a clinical decision within its operational context. We also propose revised criteria for an ideal diagnostic point-of-care test in resource-limited settings. Through systematic assessments, comparisons between centralised testing and novel point-of-care technologies can be more formalised, and health officials can better establish which point-of-care technologies represent valuable additions to their clinical programmes.

State of the art syphilis diagnostics: rapid point-of-care tests

Syphilis remains an important and entirely preventable cause of stillbirth and neonatal mortality. More than 1 million women with active syphilis become pregnant each year. Without treatment, 25% of them will deliver a stillborn baby, 33% will deliver a live low-birth weight baby with an increased chance of dying in the first month of life. Adverse pregnancy outcomes due to syphilis can be prevented by screening pregnant women, and treating those who test positive with a single dose of penicillin before 28 weeks gestation. Until recently access to screening in low- and middle-income countries has been limited, since screening tests have been laboratory based, requiring equipment, electricity and trained laboratory staff. Now a number of rapid, cheap, simple and accurate screening tests are available and can give a result in 15-20 min, enabling those who require treatment to be treated at their first visit.

Antenatal syphilis screening using point-of-care testing in Sub-Saharan African countries: a cost-effectiveness analysis

BACKGROUND

Untreated syphilis in pregnancy is associated with adverse clinical outcomes for the infant. Most syphilis infections occur in sub-Saharan Africa (SSA), where coverage of antenatal screening for syphilis is inadequate. Recently introduced point-of-care syphilis tests have high accuracy and demonstrate potential to increase coverage of antenatal screening. However, country-specific cost-effectiveness data for these tests are limited. The objective of this analysis was to evaluate the cost-effectiveness and budget impact of antenatal syphilis screening for 43 countries in SSA and estimate the impact of universal screening on stillbirths, neonatal deaths, congenital syphilis, and disability-adjusted life years (DALYs) averted.

METHODS AND FINDINGS

The decision analytic model reflected the perspective of the national health care system and was based on the sensitivity (86%) and specificity (99%) reported for the immunochromatographic strip (ICS) test. Clinical outcomes of infants born to syphilis-infected mothers on the end points of stillbirth, neonatal death, and congenital syphilis were obtained from published sources. Treatment was assumed to consist of three injections of benzathine penicillin. Country-specific inputs included the antenatal prevalence of syphilis, annual number of live births, proportion of women with at least one antenatal care visit, per capita gross national income, and estimated hourly nurse wages. In all 43 sub-Saharan African countries analyzed, syphilis screening is highly cost-effective, with an average cost/DALY averted of US$11 (range: US$2-US$48). Screening remains highly cost-effective even if the average prevalence falls from the current rate of 3.1% (range: 0.6%-14.0%) to 0.038% (range: 0.002%-0.113%). Universal antenatal screening of pregnant women in clinics may reduce the annual number of stillbirths by up to 64,000, neonatal deaths by up to 25,000, and annual incidence of congenital syphilis by up to 32,000, and avert up to 2.6 million DALYs at an estimated annual direct medical cost of US$20.8 million.

CONCLUSIONS

Use of ICS tests for antenatal syphilis screening is highly cost-effective in SSA. Substantial reduction in DALYs can be achieved at a relatively modest budget impact. In SSA, antenatal programs should expand access to syphilis screening using the ICS test. Please see later in the article for the Editors' Summary.

Advances in the diagnosis of endemic treponematoses: yaws, bejel, and pinta

Improved understanding of the differential diagnosis of endemic treponematoses is needed to inform clinical practice and to ensure the best outcome for a new global initiative for the eradication of yaws, bejel, and pinta. Traditionally, the human treponematoses have been differentiated based upon their clinical manifestations and epidemiologic characteristics because the etiologic agents are indistinguishable in the laboratory. Serological tests are still considered standard laboratory methods for the diagnosis of endemic treponematoses and new rapid point-of-care treponemal tests have become available which are extremely useful in low-resource settings. In the past ten years, there has been an increasing effort to apply polymerase chain reaction to treponematoses and whole genome fingerprinting techniques have identified genetic signatures that can differentiate the existing treponemal strains; however, definitive diagnosis is also hampered by widespread unavailability of molecular diagnostics. We review the dilemmas in the diagnosis of endemic treponematoses, and advances in the discovery of new diagnostic tools.

The trade-off between accuracy and accessibility of syphilis screening assays

The availability of rapid and sensitive methods to diagnose syphilis facilitates screening of pregnant women, which is one of the most cost-effective health interventions available. We have evaluated two screening methods in Tanzania: an enzyme immunoassay (EIA), and a point-of-care test (POCT). We evaluated the performance of each test against the Treponema pallidum particle agglutination assay (TPPA) as the reference method, and the accessibility of testing in a rural district of Tanzania. The POCT was performed in the clinic on whole blood, while the other assays were performed on plasma in the laboratory. Samples were also tested by the rapid plasma Reagin (RPR) test. With TPPA as reference assay, the sensitivity and specificity of EIA were 95.3% and 97.8%, and of the POCT were 59.6% and 99.4% respectively. The sensitivity of the POCT and EIA for active syphilis cases (TPPA positive and RPR titer ≥ 1/8) were 82% and 100% respectively. Only 15% of antenatal clinic attenders in this district visited a health facility with a laboratory capable of performing the EIA. Although it is less sensitive than EIA, its greater accessibility, and the fact that treatment can be given on the same day, means that the use of POCT would result in a higher proportion of women with syphilis receiving treatment than with the EIA in this district of Tanzania.

Usefulness in clinical practice of a point-of-care rapid test for simultaneous detection of nontreponemal and Treponema pallidum-specific antibodies in patients suffering from documented syphilis

The usefulness of a point-of-care immunochromatographic dual test for the simultaneous detection of both nontreponemal and Treponema pallidum-specific antibodies (Chembio Diagnostics Systems Inc., Medford, NY, USA) was assessed in various situations related to syphilis, by reference to conventional syphilis serology. Thawed sera were obtained from 100 adults including 36 primary syphilis, 6 secondary syphilis, 6 re-infection, 9 recently-treated syphilis, and 43 old syphilis. Doubtful reactivities for the treponemal line were considered positive; doubtful reactivities for the nontreponemal line were considered positive only when the treponemal line was present. The sensitivity, the specificity, and its concordance to gold standard serology of treponemal line were high, around 90%. The sensitivity of nontreponemal line was 96.3%, its specificity 76.7%, and its concordance 83.4%. In conclusion, the dual rapid test from Chembio Diagnostics Systems Inc. is useful for rapid point-of-care diagnosis in the various situations encountered with patients suffering from syphilis.