Laboratory diagnosis and interpretation of tests for syphilis

Serological Tests for Acquired Syphilis in Immuno-competent Patients

Serological tests represent a valuable tool for the diagnosis and monitoring the syphilis treatment. Non-treponemal antibodies are nonspecific to detect the infection, but antibody titers are used to monitor the effects of syphilis treatment. A definitive diagnosis of syphilis is made using treponemal tests, because they detect specific antibodies to the treponemal strains or treponemal fragments, which cause syphilis. These tests may remain reactive for years, sometimes for life, regardless of the therapy outcome. Even after successful treatment, approximately 85% of patients remain positive for treponemal antibodies for the rest of their lives. However, treponemal tests cannot differentiate past infections from a current infection. Therefore, we use a combination of specific and non-specific tests, the two most frequently used diagnostic algorithms. The traditional algorithm begins with a non-treponemal assay, and if it is positive, the treponemal test is done. A positive treponemal test indicates syphilis. The reverse serology algorithm detects early, primary, and treated syphilis that may be missed with traditional screening. However, non-treponemal test is necessary to detect patients with active syphilis.

Evaluation of the automated ADVIA centaur® XP syphilis assay for serological testing

We evaluated the performance of the ADVIA Centaur XP Syphilis assay (Siemens Healthcare Diagnostics, Tarrytown, NY, USA) using samples previously tested on the ARCHITECT i4000SR system (Abbott Diagnostics, Lake Forest, IL, USA) and confirmed by the Treponema pallidum particle agglutination assay (TPPA) (SERODIA-TPPA, Fujirebio Diagnostics Inc., Malvern, PA, USA). Clinical patient information was included to aid resolution of discordant samples where available. Precision, interference, and cross-reactivity were also assessed. Relative to patient clinical status, the sensitivity of both the ADVIA Centaur XP and the ARCHITECT assays was 100% (95% CI, 93.9-100), and the specificity of the ADVIA Centaur XP assay was 95.5% (95% CI, 90.4-98.3), which was slightly higher than that of the ARCHITECT assay at 93.9% (95% CI, 88.4-97.3). Overall agreement relative to patient clinical status was 96.9% (95% CI, 93.3-98.8) for the ADVIA Centaur XP assay and 95.8% (95% CI, 91.9-98.2) for the ARCHITECT assay. Overall agreement between the two automated assays was 96.9% (95% CI, 93.3-98.8). ADVIA Centaur XP assay precision was <5% at all index values tested. No significant interference was observed for lipemia or hemolysis; a small effect was seen with some samples for bilirubin. The assay exhibited no significant cross-reactivity with a number of potential interfering factors. The ADVIA Centaur XP Syphilis assay can be considered a sensitive and accurate assay for identification of treponemal antibodies in screening populations as well as patients presenting with suspicion of syphilitic infection.

Occipital lobe gumma: a case report and review of the literature

Syphilis has plagued humanity for thousands of years. Despite the measures of precaution against its transmission and the advancement of modern pharmacology, late-stage phenomena like intracerebral gumma are not uncommon even today. We present a complex case, which has misled the physicians twice. Additionally, we performed a review of the contemporary literature about the common location, clinical findings and up-to-date treatment of intracerebral gummas.

Intersecting epidemics of HIV, HCV, and syphilis among soon-to-be released prisoners in Kyrgyzstan: Implications for prevention and treatment

BACKGROUND

Central Asia is afflicted with increasing HIV incidence, low antiretroviral therapy (ART) coverage and increasing AIDS mortality, driven primarily by people who inject drugs (PWID). Reliable data about HIV, other infectious diseases, and substance use disorders in prisoners in this region is lacking and could provide important insights into how to improve HIV prevention and treatment efforts in the region.

METHODS

A randomly sampled, nationwide biobehavioural health survey was conducted in 8 prisons in Kyrgyzstan among all soon-to-be-released prisoners; women were oversampled. Consented participants underwent computer-assisted, standardized behavioural health assessment surveys and testing for HIV, HCV, HBV, and syphilis. Prevalence and means were computed, and generalized linear modelling was conducted, with all analyses using weights to account for disproportionate sampling by strata.

RESULTS

Among 381 prisoners who underwent consent procedures, 368 (96.6%) were enrolled in the study. Women were significantly older than men (40.6 vs. 36.5; p=0.004). Weighted prevalence (%), with confidence interval (CI), for each infection was high: HCV (49.7%; CI: 44.8-54.6%), syphilis (19.2%; CI: 15.1-23.5%), HIV (10.3%; CI: 6.9-13.8%), and HBV (6.2%; CI: 3.6-8.9%). Among the 31 people with HIV, 46.5% were aware of being HIV-infected. Men, compared to women, were significantly more likely to have injected drugs (38.3% vs.16.0%; p=0.001). Pre-incarceration and within-prison drug injection, primarily of opioids, was 35.4% and 30.8%, respectively. Independent correlates of HIV infection included lifetime drug injection (adjusted odds ratio [AOR]=38.75; p=0.001), mean number of years injecting (AOR=0.93; p=0.018), mean number of days experiencing drug problems (AOR=1.09; p=0.025), increasing duration of imprisonment (AOR=1.08; p=0.02 for each year) and having syphilis (AOR=3.51; p=0.003), while being female (AOR=3.06; p=0.004) and being a recidivist offender (AOR=2.67; p=0.008) were independently correlated with syphilis infection.

CONCLUSION

Drug injection, syphilis co-infection, and exposure to increased risk during incarceration are likely to be important contributors to HIV transmission among prisoners in Kyrgyzstan. Compared to the community, HIV is concentrated 34-fold higher in prisoners. A high proportion of undiagnosed syphilis and HIV infections presents a significant gap in the HIV care continuum. Findings highlight the critical importance of evidence-based responses within prison, including enhanced testing for HIV and sexually transmitted infections, to stem the evolving HIV epidemic in the region.

Performance Characteristics of the Reverse Syphilis Screening Algorithm in a Population With a Moderately High Prevalence of Syphilis

OBJECTIVES

With the recent introduction of automated treponemal tests, a new reverse syphilis algorithm has been proposed and now used by many clinical laboratories. We analyzed the impact of instituting the reverse screening syphilis algorithm in a laboratory that serves a geographic area with a moderately high prevalence of syphilis infection.

METHODS

Serum samples sent for syphilis testing were tested using a treponemal enzyme immunoassay (EIA) as the screening assay. EIA reactive samples were tested by rapid plasma reagin (RPR) and titered to end point if reactive. RPR nonreactive samples were analyzed by the Treponema pallidum particle agglutination test (TP-PA). Pertinent medical records were reviewed for false-reactive screens and samples with evidence of past syphilis infection.

RESULTS

Among 10,060 patients tested, 502 (5%) were reactive on the initial EIA screen. The RPR was reactive in 150 (1.5%). TP-PA testing determined that 103 (1.0%) were falsely reactive on initial EIA screen. The reverse screening algorithm, however, identified 242 (2.4%) with evidence of latent, secondary, or past syphilis, 21 of whom had no or unknown prior treatment with antibiotics.

CONCLUSIONS

Despite a 1.0% false-reactive rate, the reverse syphilis algorithm detected 21 patients with possible latent syphilis that may have gone undetected by traditional syphilis screening.

Otorhinolaryngology manifestations secondary to oral sex

INTRODUCTION

Over the last few years, oral and pharyngeal signs and symptoms due to oral sex have increased significantly. However, no review articles related to this subject have been found in the medical literature. The objective of our study was to identify otorhinolaryngological manifestations associated with orogenital/oroanal contact, both in adults and children, in the context of consensual sex or sexual abuse.

METHODS

We performed a review of the medical literature on otorhinolaryngological pathology associated with oral sex published in the last 20 years in the PubMed database.

RESULTS

Otorhinolaryngological manifestations secondary to oral sex practice in adults can be infectious, tumoral or secondary to trauma. The more common signs and symptoms found in the literature were human papillomavirus infection (above all, condyloma acuminata and papilloma/condyloma), oral or pharyngeal syphilis, gonococcal pharyngitis, herpes simplex virus infection and pharyngitis from Chlamydia trachomatis. The incidence of human papillomavirus -induced oropharyngeal carcinoma has dramatically increased. In children past the neonatal period, the presence of condyloma acuminatus, syphilis, gonorrhoea or palatal ecchymosis (the last one, unless justified by other causes) should make us suspect sexual abuse.

CONCLUSIONS

Sexual habits have changed in the last decades, resulting in the appearance of otorhinolaryngological pathology that was rarely seen previously. For this reason, it is important for primary care physicians to have knowledge about the subject to perform correct diagnosis and posterior treatment. Some sexual abuse cases in children may also be suspected based on the knowledge of the characteristic oropharyngeal manifestations secondary to them.

Prevalence of Traditional and Reverse-Algorithm Syphilis Screening in Laboratory Practice: A Survey of Participants in the College of American Pathologists Syphilis Serology Proficiency Testing Program

CONTEXT

-Syphilis serology screening in laboratory practice is evolving. Traditionally, the syphilis screening algorithm begins with a nontreponemal immunoassay, which is manually performed by a laboratory technologist. In contrast, the reverse algorithm begins with a treponemal immunoassay, which can be automated. The Centers for Disease Control and Prevention has recognized both approaches, but little is known about the current state of laboratory practice, which could impact test utilization and interpretation.

OBJECTIVE

-To assess the current state of laboratory practice for syphilis serologic screening.

DESIGN

-In August 2015, a voluntary questionnaire was sent to the 2360 laboratories that subscribe to the College of American Pathologists syphilis serology proficiency survey.

RESULTS

-Of the laboratories surveyed, 98% (2316 of 2360) returned the questionnaire, and about 83% (1911 of 2316) responded to at least some questions. Twenty-eight percent (378 of 1364) reported revision of their syphilis screening algorithm within the past 2 years, and 9% (170 of 1905) of laboratories anticipated changing their screening algorithm in the coming year. Sixty-three percent (1205 of 1911) reported using the traditional algorithm, 16% (304 of 1911) reported using the reverse algorithm, and 2.5% (47 of 1911) reported using both algorithms, whereas 9% (169 of 1911) reported not performing a reflex confirmation test. Of those performing the reverse algorithm, 74% (282 of 380) implemented a new testing platform when introducing the new algorithm.

CONCLUSION

-The majority of laboratories still perform the traditional algorithm, but a significant minority have implemented the reverse-screening algorithm. Although the nontreponemal immunologic response typically wanes after cure and becomes undetectable, treponemal immunoassays typically remain positive for life, and it is important for laboratorians and clinicians to consider these assay differences when implementing, using, and interpreting serologic syphilis screening algorithms.

Improving the screening of blood donors with syphilis rapid diagnostic test (RDT) and rapid plasma reagin (RPR) in low- and middle-income countries (LMIC)

BACKGROUND

Syphilis testing conventionally relies on a combination of non-treponemal and treponemal tests. The primary objective of this study was to describe the positive predictive value (PPV) of a screening algorithm in a combination of a treponemal rapid diagnostic test (RDT) and rapid plasma reagin (RPR) test at Komfo Anokye Teaching Hospital (KATH), Ghana.

MATERIALS AND METHODS

From February 2014 to January 2015, 5 mL of venous blood samples were taken from 16 016 blood donors and tested with a treponemal RDT; 5 mL of venous blood was taken from 526 consenting initial syphilis sero-reactive blood donors. These RDT reactive samples were confirmed with an algorithm, applying the Vitros^® /Abbott-Architect^® algorithm as gold standard.

RESULTS

A total of 478 of 526 RDT reactive donors were confirmed positive for syphilis, making a PPV of 90·9%. Of the 172 (32·7%) donors who were also RPR positive, 167 were confirmed, resulting in a PPV of 97·1%. The PPV of the combined RDT and RPR (suspected active syphilis) testing algorithm was highest among donors at an enhanced risk of syphilis, family/replacement donors (99·9%), and among voluntary donors above 25 years (98·6%).

DISCUSSION

Screening of blood donors by combining syphilis RDT and RPR with relatively good PPV may provide a reasonable technology for LMIC that has a limited capacity for testing and can contribute to the improvement of blood safety with a minimal loss of donors.

Neurosyphilis

PURPOSE OF REVIEW

This article reviews the etiology, clinical manifestations, diagnosis, and treatment of neurosyphilis, with a focus on issues of particular relevance to neurologists.

RECENT FINDINGS

The number of cases of infectious syphilis in the United States has steadily increased since 2000. The highest rates are among men who have sex with men, and approximately half of these individuals are infected with human immunodeficiency virus (HIV). Neurosyphilis is a serious complication of syphilis that can develop at any time in the course of syphilis. Two neuroimaging patterns should alert the neurologist to a diagnosis of neurosyphilis: cerebral gummas, which are dural-based lesions that can mimic meningiomas, and medial temporal lobe abnormalities that can mimic herpes encephalitis. Penicillin G is the recommended treatment for neurosyphilis, but ceftriaxone may be an acceptable alternative.

SUMMARY

The diagnosis of neurosyphilis can be challenging. A sound understanding of the clinical manifestations and the strengths and limitations of diagnostic tests are essential tools for the neurologist.

Detection of Treponema pallidum Sp. Pallidum DNA in Cerebrospinal Fluid (CSF) by Two PCR Techniques

BACKGROUND

Laboratory diagnosis of neurosyphilis is complicated especially when it is asymptomatic, no single laboratory test result being appropriate to diagnose central nervous system infectivity caused by Treponema pallidum. Our objective was to evaluate two polymerase chain reaction (PCR) techniques for the detection of T. pallidum DNA in the cerebrospinal fluid (CSF) of patients with syphilis.

METHODS

One hundred twenty-four CSF samples from patients with reactive blood tests for syphilis were obtained. Two PCR techniques (47-PCR, polA-PCR) were used to detect T. pallidum DNA. The laboratory criteria used for the diagnosis of neurosyphilis to which the PCR techniques were compared were those recommended by the IUSTI: 2008 European guidelines on the management of syphilis.

RESULTS

Treponema pallidum DNA was detected amplified in 37 of 124 (29.8%) and 30 of 124 (24.2%) samples with the 47-PCR and polA-PCR, respectively. Sensitivities were 75.8% and 69.7% and specificities 86.8% and 92.3%, respectively, for 47-PCR and polA-PCR techniques, respectively. The three CSF samples of patients with primary syphilis did not fulfill the criteria of neurosyphilis and DNA was only detected in one by the 47-PCR. In samples from secondary syphilis and neurosyphilis, three of nine and nine of nine respectively, results were coincident for the two PCR techniques and neurosyphilis criteria. Major discrepancies between the two PCR techniques and neurosyphilis diagnostic criteria were observed in latent syphilis.

CONCLUSION

Beyond some limitations of the study, which are discussed here, both PCR techniques seem to be useful for the diagnosis of neurosyphilis, although 47-PCR presents a higher sensitivity and polA-PCR a higher specificity.

Incidence of and temporal relationships between HIV, herpes simplex II virus, and syphilis among men who have sex with men in Bangkok, Thailand: an observational cohort

Background

High HIV incidence has been detected among men who have sex with men (MSM) in Thailand, but the relationship and timing of HIV, herpes simplex virus 2 (HSV-2), and syphilis is unknown. This analysis measures incidence, temporal relationships, and risk factors for HIV, HSV-2, and syphilis among at-risk MSM in the Bangkok MSM Cohort Study.

Methods

Between April 2006 and December 2010, 960 men negative for HIV, HSV-2, and syphilis at entry enrolled and contributed 12–60 months of follow-up data. Behavioral questionnaires were administered at each visit; testing for HIV antibody was performed at each visit, while testing for syphilis and HSV-2 were performed at 12 month intervals. We calculated HIV, HSV-2, and syphilis incidence, assessed risk factors with complementary log-log regression, and among co-infected men, measured temporal relationships between infections with Kaplan-Meier survival analysis and paired t-test.

Results

The total number of infections and incidence density for HIV, HSV-2, and syphilis were 159 infections and 4.7 cases/100 PY (95 % Confidence Interval (CI): 4.0–5.4), 128 infections and 4.5/100 PY (95 % CI: 3.9–5.5), and 65 infections and 1.9/100 PY (95 % CI: 1.5–2.5), respectively. Among men acquiring >1 infection during the cohort period, mean time to HIV and HSV-2 infection was similar (2.5 vs. 2.9 years; p = 0.24), while syphilis occurred significantly later following HIV (4.0 vs. 2.8 years, p < 0.01) or HSV-2 (3.8 vs. 2.8 years, p = 0.04) infection. The strongest independent predictor of any single infection in adjusted analysis was acquisition of another infection; risk of syphilis (Adjusted Hazards Ratio (AHR) = 3.49, 95 % CI: 1.89–6.42) or HIV (AHR = 2.26, 95 % CI: 1.47–3.48) acquisition during the cohort was significantly higher among men with incident HSV-2 infection. No single independent behavioral factor was common to HIV, HSV-2, and syphilis acquisition.

Conclusion

HIV and HSV-2 incidence was high among this Thai MSM cohort. However, acquisition of HIV and co-infection with either HSV-2 or syphilis was low during the time frame men were in the cohort. Evaluation of behavioral risk factors for these infections suggests different risks and possible different networks.

Secondary Syphilis With Hepatitis and Nephrotic Syndrome: A Rare Concurrence

Syphilis, a chronic multisystem disease, is caused by a spirochete, Treponema pallidum. Clinical presentation may expand to several stages including primary, secondary and latent syphilis, which may present as early or late syphilis. Nephrotic syndrome and acute hepatitis are well-known complications of secondary syphilis. To the best of our knowledge, secondary syphilis with coexisting renal and hepatic complications has rarely been reported. Here we present a rare case of concurrent nephrotic syndrome and acute hepatitis in a patient with secondary syphilis.

Dual rapid lateral flow immunoassay fingerstick wholeblood testing for syphilis and HIV infections is acceptable and accurate, Port-au-Prince, Haiti

BACKGROUND

Dual rapid tests for HIV and syphilis infections allow for detection of HIV infection and syphilis at the point-of-care. Those tests have been evaluated in laboratory settings and show excellent performance but have not been evaluated in the field. We evaluated the field performance of the SD BIOLINE HIV/Syphilis Duo test in Port-au-Prince, Haiti using whole blood fingerprick specimens.

METHODS

GHESKIO (Haitian Study Group for Kaposi's Sarcoma and Opportunistic Infections) clinic attendees 18 years of age or older were invited to participate. Venipuncture blood specimens were used for reference testing with standard commercially available tests for HIV and syphilis in Haiti. The sensitivity and specificity of the Duo test compared to the reference standard were calculated. The exact binomial method was used to determine 95 % confidence intervals (CI).

RESULTS

Of 298 study participants, 237 (79.5 %) were female, of which 49 (20.7 %) were pregnant. For the HIV test component, the sensitivity and specificity were 99.2 % (95 % CI: 95.8 %, 100 %) and 97.0 % (95 % CI: 93.2 %, 99.0 %), respectively; and for the syphilis component were 96.5 % (95 % CI: 91.2 %, 99.0 %) and 90.8 % (95 % CI: 85.7 %, 94.6 %), respectively. In pregnant women, the sensitivity and specificity of the HIV test component were 93.3 % (95 % CI: 68.0 %, 99.8 %) and 94.1 % (95 % CI: 80.3 %, 99.3 %), respectively; and for the syphilis component were 100 % (95 % CI:81.5 %, 100 %) and 96.8 % (95 % CI:83.3 %, 99.9 %), respectively.

CONCLUSION

The Standard Diagnostics BIOLINE HIV/Syphilis Duo dual test performed well in a field setting in Haiti and should be considered for wider use.

Clinical Evaluation of Fully Automated Elecsys® Syphilis Assay for the Detection of Antibodies of Treponema pallidum

OBJECTIVE

The resurgence of syphilis in recent years has become a serious threat to the public health worldwide, and the serological detection of specific antibodies against Treponema pallidum (TP) remains the most reliable method for laboratory diagnosis of syphilis. The performance of the Elecsys^® Syphilis assay, a brand new electrochemiluminescene immunoassay (ECLIA), was assessed by large amounts of samples in this study.

METHODS

In comparison with InTec assay, the Elecsys^® Syphilis assay was evaluated in 146 preselected samples from patients with syphilis, 1803 clinical routine samples, and 175 preselected samples from specific populations with reportedly increased rates of false-positive syphilis test results. Discrepancy samples must be investigated by Mikrogen Syphilis recomline assay.

RESULTS

There was an overall agreement of 99.58% between two assays (Kappa = 0.975). The sensitivity and specificity of the Elecsys^® Syphilis assay were 100.0% (95% CI, 96.8-100.0%) and 99.8% (95% CI, 99.5-100.0%), respectively. The Elecsys syphilis assay displays better sensitivity (100%), specificity (99.8%), PPV (98.7%), and NPV (100%) in 2124 samples enrolled, compared with the InTec assay.

CONCLUSION

Considering the excellent ease of use and automation, high throughput, and its superior sensitivity, especially in primary syphilis, the Elecsys^® Syphilis assay could represent an outstanding choice for screening of syphilis in high-volume laboratories. However, more attention was still needed, or the results must be confirmed by other treponemal immunoassays. The new Elecsys^® Syphilis assay is applied to patients with malignant neoplasm or HIV infection.

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.

Syphilis: presentations in general medicine

Syphilis is caused by the spirochete bacteriumTreponema pallidumand can be transmitted both sexually and from mother to child.T pallidumcan infect any organ and produces a clinical disease with a relapsing and remitting course. It is not hard to see, therefore, why it is often described as the great mimic. In this review, we provide an update of modern syphilis epidemiology, clinical presentations, and testing and treatment strategies.

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.

A Sero-epidemiological Approach to Explore Transmission of Mycobacterium ulcerans

The debilitating skin disease Buruli ulcer (BU) is caused by infection with Mycobacterium ulcerans. While various hypotheses on potential reservoirs and vectors of M. ulcerans exist, the mode of transmission has remained unclear. Epidemiological studies have indicated that children below the age of four are less exposed to the pathogen and at lower risk of developing BU than older children. In the present study we compared the age at which children begin to develop antibody responses against M. ulcerans with the age pattern of responses to other pathogens transmitted by various mechanisms. A total of 1,352 sera from individuals living in the BU endemic Offin river valley of Ghana were included in the study. While first serological responses to the mosquito transmitted malaria parasite Plasmodium falciparum and to soil transmitted Strongyloides helminths emerged around the age of one and two years, sero-conversion for M. ulcerans and for the water transmitted trematode Schistosoma mansoni occurred at around four and five years, respectively. Our data suggest that exposure to M. ulcerans intensifies strongly at the age when children start to have more intense contact with the environment, outside the small movement range of young children. Further results from our serological investigations in the Offin river valley also indicate ongoing transmission of Treponema pallidum, the causative agent of yaws.

A novel ELISA using a recombinant outer membrane protein, rTp0663, as the antigen for serological diagnosis of syphilis

BACKGROUND

The lack of Treponema pallidum-specific antigens with highly accurate diagnosis makes the diagnosis of syphilis challenging.

METHODS

A soluble recombinant version of a new diagnostic protein Tp0663 has been produced. The serodiagnostic potential of this protein was assessed by screening 3326 serum samples simultaneously evaluated by rapid plasma reagin and T. pallidum particle agglutination tests. Kappa (κ) coefficients were used to compare the concordance between clinical diagnosis and the Tp0663-based ELISA or the ARCHITECT Syphilis TP chemiluminescent immunoassay (Abbott GmbH and Co. KG).

RESULTS

Using the results of clinical diagnosis as the gold standard, the sensitivity and specificity of Tp0663 were found to be 98.83% (95% confidence interval (CI) 96.61-99.60%) and 100% (95% CI 99.88-100%), respectively. In comparison, the ARCHITECT Syphilis TP assay was found to have a lower sensitivity (97.27%, 95% CI 94.46-98.67%) and specificity (99.61%, 95% CI 99.32-99.78%). In particular, the ARCHITECT Syphilis TP exhibited a false-positive rate of 0.39%. Moreover, the ELISA was in perfect agreement with the gold standard, with a κ value of 0.99, comparable to that of ARCHITECT Syphilis TP (0.96).

CONCLUSION

These results identified Tp0663 as a novel serodiagnostic candidate with great potential for developing novel tests for the diagnosis of syphilis.

Screening for antibodies against Treponema pallidum with chemiluminescent microparticle immunoassay: analysis of discordant serology results and clinical characterization

BACKGROUND

Traditionally, testing for syphilis has consisted of initial screening with a non-treponemal test, then retesting reactive specimens with a treponemal test. Recent availability of a chemiluminescent microparticle immunoassay for detecting antibodies against Treponema pallidum has led several laboratories in China to adopt chemiluminescent microparticle immunoassay for screening of syphilis, with subsequent testing of reactive serum samples with non-treponemal tests. We evaluated the utility of chemiluminescent microparticle immunoassay for routine screening of syphilis.

METHODS

Antibodies against Treponema pallidum were screened in 20,550 serum samples using chemiluminescent microparticle immunoassay. Chemiluminescent microparticle immunoassay-positive samples were reflexively tested with rapid plasma reagin tests and Treponema pallidum particle agglutination assays. Dot-immunoblot assays were used to confirm results of chemiluminescent microparticle immunoassay-positive and Treponema pallidum particle agglutination-negative serum samples.

RESULTS

Overall, 267 samples (1.3%) were chemiluminescent microparticle immunoassay-positive, and 185 (69.3%) of those chemiluminescent microparticle immunoassay-positive serum samples were also Treponema pallidum particle agglutination-positive. Samples' signal to cut-off ratio for chemiluminescent microparticle immunoassay correlated with diagnostic reliability, as greater samples' signal to cut-off ratio corresponded with greater concordance between chemiluminescent microparticle immunoassay and Treponema pallidum particle agglutination results. Dot-immunoblot testing of 82 chemiluminescent microparticle immunoassay-positive and Treponema pallidum particle agglutination-negative serum samples showed that 16 samples (19.5%) were Dot-immunoblot-positive, 28 (34.2%) were indeterminate and 38 (46.3%) were negative.

CONCLUSIONS

Because there is a certain percentage of false-positive results using chemiluminescent microparticle immunoassay for routine screening of syphilis, further analysis by Treponema pallidum particle agglutination is recommended to confirm diagnostic results. While in screening populations discrepancies between chemiluminescent microparticle immunoassay and Treponema pallidum particle agglutination results are quite prevalent, confirmation by immunoblot assay may be useful.

A systematic review of syphilis serological treatment outcomes in HIV-infected and HIV-uninfected persons: rethinking the significance of serological non-responsiveness and the serofast state after therapy

BACKGROUND

Syphilis remains a global public health threat and can lead to severe complications. In addition to resolution of clinical manifestations, a reduction in nontreponemal antibody titers after treatment is regarded as "proof of cure." However, some patients manifest < 4-fold decline ("serological non-response") or persistently positive nontreponemal titers despite an appropriate decline ("serofast") that may represent treatment failure, reinfection, or a benign immune response. To delineate these treatment phenomena, we conducted a systematic review of the literature regarding serological outcomes and associated factors among HIV-infected and -uninfected subjects.

METHODS

Six databases (PubMed, Embase, CINAHL, Web of Science, Scopus, and BIOSIS) were searched with no date restrictions. Relevant articles that evaluated serological treatment responses and correlates of serological cure (≥ four-fold decline in nontreponemal titers) were included.

RESULTS

We identified 1693 reports in the literature, of which 20 studies met selection criteria. The median proportion of patients who had serological non-response was 12.1% overall (interquartile range, 4.9-25.6), but varied depending on the time points after therapy. The serofast proportion could only be estimated from 2 studies, which ranged from 35.2-44.4%. Serological cure was primarily associated with younger age, higher baseline nontreponemal titers, and earlier syphilis stage. The relationship between serological cure and HIV status was inconsistent; among HIV-infected patients, CD4 count and HIV viral load was not associated with serological cure.

CONCLUSIONS

Serological non-response and the serofast state are common syphilis treatment outcomes, highlighting the importance of determining the immunological and clinical significance of persistent nontreponemal antibody titers after therapy.

Genital infections and risk of premature rupture of membranes in Mulago Hospital, Uganda: a case control study

Background

Inflammatory mediators that weaken and cause membrane rupture are released during the course of genital infections among pregnant women. We set out to determine the association of common genital infections (Trichomonas vaginalis, syphilis, Neisseria gonorrhea, Chlamydia trachomatis, Group B Streptococcus, Bacterial vaginosis, Herpes Simplex Virus Type 2 and candidiasis) and premature rupture of membranes in Mulago hospital, Uganda.

Methods

We conducted an unmatched case–control study among women who were in the third trimester of pregnancy at New Mulago hospital, Uganda. The cases had PROM and the controls had intact membranes during latent phase of labour in the labour ward. We used interviewer-administered questionnaires to collect data on socio-demographic characteristics, obstetric and medical history. Laboratory tests were conducted to identify T. vaginalis, syphilis, N. gonorrhea, C. trachomatis, Group B Streptococcus, Bacterial vaginosis, Herpes Simplex Virus Type 2 (HSV-2) and candidiasis. Logistic regression models were used to estimate the odds ratios (OR) and 95 % CI of the association between genital infections and PROM.

Results

There was an association between PROM and abnormal vaginal discharge (OR = 2.02, 95 % CI 1.10–3.70 and AOR = 2.30, 95 % CI 1.18–4.47), presence of candidiasis (OR = 0.27, 95 % CI 0.14–0.52 and AOR = 0.22, 95 % CI 0.10–0.46) and T. vaginalis (OR = 2.98, 95 % CI 1.18–7.56 and AOR = 4.22, 95 % CI 1.51–11.80). However, there was no association between PROM and presence of C. trachomatis (OR = 2.05, 95 % CI 0.37–11.49) and HSV-2 serostatus (OR = 1.15, 95 % CI 0.63–2.09). Few or no patients with Bacterial vaginosis, Neisseria gonorrhoea, Group B streptococcus or syphilis were identified among the cases and controls. Co-infection of Trichomoniasis and candidiasis was not associated with PROM (AOR = 1.34, 95 % CI 0.16–11.10). Co infection with T. vaginalis and C. trachomatis was associated with PROM (OR = 3.09, 95 % CI 1.21–7.84 and AOR = 4.22, 95 % CI 1.51–11.83).

Conclusion

Trichomonas vaginalis alone, T. vaginalis with C. trachomatis co-infection and abnormal per vaginal discharge were found as risk factors for PROM. There was no association of HSV-2 serostatus, syphilis, N. gonorrhea, C. trachomatis, Group B Streptococcus and Bacterial vaginosis with PROM. Candidiasis seemed to have a protective effect on PROM.

Tertiary syphilis and Kaposi sarcoma mistaken for systemic sarcoidosis in an HIV-negative patient

We describe a case of an HIV-negative man who was mistakenly diagnosed as having systemic sarcoidosis, which led to a delay in diagnosing tertiary syphilis and Kaposi sarcoma (KS). The patient presented initially with scrotal swelling and leg oedema. Initial blood tests were unremarkable and HIV testing was negative. The patient then developed unilateral limb weakness. Computed tomography showed lung lesions and hilar lymphadenopathy, while magnetic resonance imaging showed an increased signal in the cervical cord. Serum angiotensin-converting enzyme was raised, and a diagnosis of sarcoidosis was made and the patient started on steroids. Subsequently, his clinical symptoms and radiological abnormalities improved. However, he then developed progressive neurological deficits over several weeks, together with uveitis and cutaneous lesions. A uveitis screen showed a raised venereal disease research laboratory test titre and the cause of his multisystemic symptoms was revisited. He was diagnosed with tertiary syphilis and treated with antibiotics. Dermatologists reviewed the skin lesions and diagnosed KS, which was confirmed with biopsies. The patient's neurological deficit remains. Syphilis should be considered in the differential diagnosis of any patient presenting with neurological problems, skin lesions or symptoms affecting multiple systems. Co-existing KS presented an extra therapeutic challenge in this case.

Erythematous candidiasis leading to systemic manifestations of human immunodeficiency virus co-infection with secondary syphilis: A diagnostic and therapeutic dilemma

The intensification of human immunodeficiency virus (HIV) and rising frequency of immunocompromised individuals have resulted in a resurgence of opportunistic infections. The most common opportunistic oral fungal infection in HIV-positive individuals is oral candidiasis. The classical presentation is as white scrapable form called as thrush, which is easily diagnosed and treated. The clinician is presented with a diagnostic and management dilemma when these lesions appear in new facades such as erythematous candidiasis, the latter's prevalence with HIV and AIDS being well established. In this case report, we present a case of Erythematous Candidiasis, which was associated with type 1 HIV co-infected with syphilis. We highlight the diagnostic importance of a naive looking manifestation of the tongue which was followed by a series of challenging presentations of secondary syphilis. Since the patient had a negative Veneral Disease Research Laboratory and left us with a management dilemma, the article also features the importance of prozone phenomenon (seen in 2% cases of secondary syphilis), and it's higher association with HIV co-infected individuals. With confusing clinical oral manifestations associated with these diseases, the dentist might be the first person to encounter such lesions, who should be able to recognize erythematous candidiasis and correlate them with the underlying pathology.

Use of Treponema pallidum PCR in testing of ulcers for diagnosis of primary syphilis

Treponema pallidum PCR (Tp-PCR) has been noted as a valid method for diagnosing syphilis. We compared Tp-PCR to a combination of darkfield microscopy (DFM), the reference method, and serologic testing in a cohort of 273 patients from France and Switzerland and found the diagnostic accuracy of Tp-PCR was higher than that for DFM.

Syphilis testing, typing, and treatment follow-up: a new era for an old disease

PURPOSE OF REVIEW

The past 15 years have seen a dramatic increase in syphilis diagnoses in several regions including China, North America, Western Europe and Australia. Worldwide, the disease remains prevalent, contributing to substantial adult morbidity and neonatal mortality. Testing and treatment strategies are largely informed by data from the early antibiotic era, but increasing use of molecular diagnostics and new screening strategies could improve the management of syphilis substantially.

RECENT FINDINGS

The review explores new testing strategies for syphilis, including the importance of screening test selection and advances in point-of-care diagnostics. It then examines molecular studies of Treponema pallidum, covering typing; macrolide resistance; association between genotype and phenotype and the use of PCR in testing and monitoring strategies.

SUMMARY

Clinicians should be aware of testing strategies employed by their laboratories to ensure optimal sensitivity and specificity. Locally available T. pallidum PCR assays may improve the diagnosis of early disease and inform antibiotic choice. Robust serologic follow-up is still required, but predictors of potential treatment failure, including PCR-measured bacterial load, have been identified. Re-treatment should be considered for patients in the serofast state. The publication of T. pallidum genomes would allow further and more detailed study of strains and disease pathogenesis.

Nodular mucinosis misdiagnosed as non-responsive secondary syphilis

A previously healthy 24-year-old man presented with an erythematous, non-pruritic and painless papulonodular skin rash affecting the trunk, upper arms (excluding palms), neck, face, forehead and scalp. He had a penile ulcer for the past 2 weeks, almost healed at the time of observation. The patient tested positive for syphilis and HIV-1; he claimed being negative for HIV 6 months earlier. As the palms were not affected, we performed a skin biopsy for the differential diagnosis between secondary lues and acute HIV seroconversion reaction. Benzathine penicillin (2,400,000 units) was administrated and antiretroviral therapy started. Although the skin biopsy was compatible with secondary syphilis, there was no change in the skin rash 3 weeks after the first penicillin administration. Another 2 doses of penicillin were given but 4 weeks later the rash persisted. A second biopsy revealed a mucinous skin infiltration, compatible with nodular mucinosis.

DNA Microarray Characterization of Pathogens Associated with Sexually Transmitted Diseases

This study established a multiplex PCR-based microarray to detect simultaneously a diverse panel of 17 sexually transmitted diseases (STDs)-associated pathogens including Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma, Herpes simplex virus (HSV) types 1 and 2, and Human papillomavirus (HPV) types 6, 11, 16, 18, 31, 33, 35, 39, 54 and 58. The target genes are 16S rRNA gene for N. gonorrhoeae, M. genitalium, M. hominism, and Ureaplasma, the major outer membrane protein gene (ompA) for C. trachomatis, the glycoprotein B gene (gB) for HSV; and the L1 gene for HPV. A total of 34 probes were selected for the microarray including 31 specific probes, one as positive control, one as negative control, and one as positional control probe for printing reference. The microarray is specific as the commensal and pathogenic microbes (and closely related organisms) in the genitourinary tract did not cross-react with the microarray probes. The microarray is 10 times more sensitive than that of the multiplex PCR. Among the 158 suspected HPV specimens examined, the microarray showed that 49 samples contained HPV, 21 samples contained Ureaplasma, 15 contained M. hominis, four contained C. trachomatis, and one contained N. gonorrhoeae. This work reports the development of the first high through-put detection system that identifies common pathogens associated with STDs from clinical samples, and paves the way for establishing a time-saving, accurate and high-throughput diagnostic tool for STDs.

Evaluation of the HISCL Anti-Treponema pallidum Assay as a Screening Test for Syphilis

The resurgence of syphilis in recent years has become a serious threat to public health worldwide, and the serological detection of specific antibodies against Treponema pallidum remains the most reliable method for laboratory diagnosis of syphilis. This study examined the performance of the recently launched HISCL anti-Treponema pallidum (anti-TP) assay as a screening test for syphilis in a high-volume laboratory. The HISCL anti-TP assay was tested in 300 preselected syphilis-positive samples, 704 fresh syphilis-negative samples, 48 preselected potentially interfering samples, and 30 "borderline" samples and was compared head to head with the commercially available Lumipulse G TP-N. In this study, the HISCL anti-TP assay was in perfect agreement with the applied testing algorithms with an overall agreement of 100%, comparable to that of Lumipulse G TP-N (99.63%). The sensitivity and specificity of the HISCL anti-TP assay were 100% (95% confidence interval [CI], 98.42% to 100%) and 100% (95% CI, 99.37% to 100%), respectively. Considering the excellent ease of use and automation, high throughput, and its favorable sensitivity and specificity, the HISCL anti-TP assay may represent a new choice for syphilis screening in high-volume laboratories.

Failure of PCR to Detect Treponema pallidum ssp. pertenue DNA in Blood in Latent Yaws

Yaws, caused by Treponema pallidum ssp. pertenue, is a neglected tropical disease closely related to venereal syphilis and is targeted for eradication by 2020. Latent yaws represents a diagnostic challenge, and current tools cannot adequately distinguish between individuals with true latent infection and individuals who are serofast following successful treatment. PCR on blood has previously been shown to detect T. pallidum DNA in patients with syphilis, suggesting that this approach may be of value in yaws. We performed real-time PCR for Treponema pallidum ssp. pertenue on blood samples from 140 children with positive T. pallidum Particle Agglutination (TPPA) and Rapid Plasma Reagin (RPR) tests and 7 controls (negative serology), all collected as part of a prospective study of yaws in the Solomon Islands. All samples were also tested by a nested PCR for T. pallidum. 12 patients had clinical evidence of active yaws whilst 128 were considered to have latent yaws. 43 children had high titre rapid plasma reagins (RPRs) of ≥1:32. PCR testing with both assays gave negative results in all cases. It is possible that the failure to detect T. pallidum ssp. pertenue in blood reflects lower loads of organism in latent yaws compared to those in latent infection with T. pallidum ssp. pertenue, and/or a lower propensity for haematogenous dissemination in yaws than in syphilis. As the goal of the yaws control programme is eradication, a tool that can differentiate true latent infection from individuals who are serofast would be of value; however, PCR of blood is not that tool.

Yaws is a bacterial infection closely related to syphilis. The WHO has launched a worldwide campaign to eradicate yaws by 2020. For each clinically apparent case, many close contacts are infected but do not show clinical signs, which is called latent yaws. Currently, diagnosis for these patients relies on the detection of antibodies using syphilis serology. Reliance on detection of antibodies for diagnosis of latent yaws is problematic as the test may remain positive with a low titre despite successful treatment. This makes the interpretation of surveillance data in a post-mass treatment setting difficult for programme managers. In syphilis, PCR can detect T. pallidum ssp. pallidum in the blood of patients with latent disease. We used similar techniques to try and detect the yaws bacterium in the blood of patients seen as part of a study of yaws in the Solomon Islands. Although many people had positive antibodies for yaws consistent with latent yaws, we were unable to detect the bacterium in the blood. This may reflect the lower virulence of the yaws bacterium compared to syphilis. Currently available molecular techniques are therefore not able to aid programme managers in conducting post-mass drug administration surveillance for latent yaws. The development of alternative diagnostic tests should be considered.

Improving syphilis screening in deceased organ donors

BACKGROUND

Current U.S. policy requires screening of all deceased organ donors for syphilis infection. To date, information on syphilis test performance in this population is limited.

METHODS

All donors with a positive rapid plasma reagin (RPR) and matched donors with negative RPR who were evaluated by one organ procurement organization from January 1, 2000, to September 30, 2012, were retrospectively tested, using retained, residual serum, with two alternate RPR tests and four treponemal-specific tests: A fluorescent treponemal antibody absorption test, a microhemagglutination test, a chemiluminescence immunoassay (CLIA), and a Treponema pallidum particle agglutination (TP-PA) test.

RESULTS

Thirty-two of 3,555 (0.9%) potential deceased organ donors screened during the study period showed a positive RPR; 61 RPR-negative matched donor samples were studied as well. Thirteen (40.6%) of the RPR-positive donors were found to be false-positive based on confirmatory TP-PA. As compared to TP-PA, the sensitivity of the fluorescent treponemal antibody absorption, microhemagglutination, and CLIA was 87.5%, 91.7% and 100%, respectively. The CLIA and TP-PA results were 100% concordant. Only 17 (53.1%) of the RPR-positive donors had a total of 46 organs recovered for transplantation.

CONCLUSION

Current screening of deceased organ donors by RPR yields a significant number of false-positive results. Use of alternative tests or the routine use of confirmatory tests may reduce the frequency of false-positive results in deceased organ donors.

Public health interventions to control syphilis

Syphilis control strategies are old, but interventions have changed and there is now a more scientific approach to evidence of effectiveness. We searched PubMed using 'syphilis control' to identify papers that measured the effectiveness of interventions. We also included novel approaches and comprehensive responses to outbreaks. Few papers used high-quality research methodology and fewer evaluated impact on prevalence or incidence; most assessed intermediate outcomes. Syphilis can often be controlled by a combination of case finding, treatment and education. However, outbreaks are unique and ongoing evaluation is needed to see if interventions are producing intended intermediate outcomes at reasonable costs.

Demographic determinants of syphilis seroprevalence among U.S. blood donors, 2011-2012

BACKGROUND

No cases of transfusion-transmitted syphilis have been described for over four decades. While there is mandatory transfusion screening for syphilis, the absence of transmission is in part ascribed to a low prevalence of syphilis in the blood donor population, the concomitant use of antibiotics in a high proportion of transfusion recipients, allied with poor survival of T. pallidum during refrigerated storage of blood products.

METHODS

A cross-sectional retrospective data analysis was conducted to ascertain the prevalence of Treponema pallidum antibodies in U.S. blood donors by demography and geography. Routine blood donation testing data and demographics were extracted from the data warehouse of a large network of U.S. blood centers. Crude and adjusted prevalence of T. pallidum antibodies and active syphilis infection were calculated, and GIS mapping was used to illustrate geographic distribution.

RESULTS

The prevalence of T. pallidum seropositivity and active syphilis in first time donors was 162.6 (95% CI 145.5-181.2) per 100,000 donors and 15.8 (95% CI 10.8-22.3) per 100,000 donors, respectively. The odds of T. pallidum seropositivity were significantly elevated in African American (OR = 18.9, 95% CI 14.2-25.2), and Hispanic (OR = 2.8, 95% CI 2.0-3.8) as compared to Caucasian donors. Similarly, the odds of active T. pallidum infections were significantly higher in African American (OR 15.0, 95% CI 7.0-32.3) and Hispanic (OR = 5.8, 95% CI 2.9-11.6) as compared to Caucasian donors. Syphilis seropositivity was associated with first time blood donation, increasing age, lower education, birth outside the US, and positive tests for HIV and HCV. Geographically, T. pallidum seropositivity was increased in southern and western regions of the US.

CONCLUSIONS

Given the low seroprevalence of syphilis in blood donors, continued screening remains debatable; however it may provide a public health benefit through surveillance of at-risk populations.

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.

Yaws

INTRODUCTION

Yaws, caused by Treponema pallidum ssp. pertenue, is endemic in parts of West Africa, Southeast Asia and the Pacific. The WHO has launched a campaign based on mass treatment with azithromycin, to eradicate yaws by 2020.

SOURCES OF DATA

We reviewed published data, surveillance data and data presented at yaws eradication meetings.

AREAS OF AGREEMENT

Azithromycin is now the preferred agent for treating yaws. Point-of-care tests have demonstrated their value in yaws.

AREAS OF CONTROVERSY

There is limited data from 76 countries, which previously reported yaws. Different doses of azithromycin are used in community mass treatment for yaws and trachoma.

GROWING POINTS

Yaws eradication appears an achievable goal. The programme will require considerable support from partners across health and development sectors.

AREAS TIMELY FOR DEVELOPING RESEARCH

Studies to complete baseline mapping, integrate diagnostic tests into surveillance and assess the impact of community mass treatment with azithromycin are ongoing.

Canadian Public Health Laboratory Network laboratory guidelines for congenital syphilis and syphilis screening in pregnant women in Canada

Despite universal access to screening for syphilis in all pregnant women in Canada, cases of congenital syphilis have been reported in recent years in areas experiencing a resurgence of infectious syphilis in heterosexual partnerships. Antenatal screening in the first trimester continues to be important and should be repeated at 28 to 32 weeks and again at delivery in women at high risk of acquiring syphilis. The diagnosis of congenital syphilis is complex and is based on a combination of maternal history and clinical and laboratory criteria in both mother and infant. Serologic tests for syphilis remain important in the diagnosis of congenital syphilis and are complicated by the passive transfer of maternal antibodies which can affect the interpretation of reactive serologic tests in the infant. All infants born to mothers with reactive syphilis tests should have nontreponemal tests (NTT) and treponemal tests (TT) performed in parallel with the mother's tests. A fourfold or higher titre in the NTT in the infant at delivery is strongly suggestive of congenital infection but the absence of a fourfold or greater NTT titre does not exclude congenital infection. IgM tests for syphilis are not currently available in Canada and are not recommended due to poor performance. Other evaluation in the newborn infant may include long bone radiographs and cerebrospinal fluid tests but all suspect cases should be managed in conjunction with sexually transmitted infection and/or pediatric experts.

Canadian Public Health Laboratory Network laboratory guidelines for the use of serological tests (excluding point-of-care tests) for the diagnosis of syphilis in Canada

Syphilis, caused by the bacterium Treponema pallidum subsp. pallidum, is an infection recognized since antiquity. It was first reported at the end of the 15th century in Europe. Infections may be sexually transmitted as well as spread from an infected mother to her fetus or through blood transfusions. The laboratory diagnosis of syphilis infection is complex. Because this organism cannot be cultured, serology is used as the principal diagnostic method. Some of the issues related to serological diagnoses are that antibodies take time to appear after infection, and serology screening tests require several secondary confirmatory tests that can produce complex results needing interpretation by experts in the field. Traditionally, syphilis screening was performed using either rapid plasma reagin or Venereal Disease Research Laboratory tests, and confirmed by treponemal tests such as MHA-TP, TPPA or FTA-Abs. Currently, that trend is reversed, ie, most of the laboratories in Canada now screen for syphilis using treponemal enzyme immunoassays and confirm the status of infection using rapid plasma reagin or Venereal Disease Research Laboratory tests; this approach is often referred to as the reverse algorithm. This chapter reviews guidelines for specimen types and sample collection, treponemal and non-treponemal tests utilized in Canada, the current status of serological tests for syphilis in Canada, the complexity of serological diagnosis of syphilis infection and serological testing algorithms. Both traditional and reverse sequence algorithms are recommended and the algorithm used should be based on a combination of local disease epidemiology, test volumes, performance of the proposed assays and available resources.

Evaluation of diagnostic serological results in cases of suspected primary syphilis infection

BACKGROUND

Reverse sequence screening for syphilis, in which an automatable treponemal assay (enzyme immunoassay [EIA]/chemiluminescence assay [CIA]) is performed first and followed by a nontreponemal test for reactive specimens, has been used increasingly in the United States. The EIA is objective, efficient, and believed to be more sensitive than the rapid plasma reagin (RPR) because treponemal antibodies appear before nontreponemal antibodies. We sought to compare the sensitivity of a commonly used EIA, the Trep-Sure EIA (TS-EIA), to the RPR in cases of suspected primary syphilis infection in our clinic.

METHODS

A retrospective medical record review of patients with sexually transmitted infection clinic visits from January 2009 to December 2011 was conducted, and 52 patients met the following inclusion criteria: suspected primary syphilis symptoms, at least 1 positive syphilis test result at visit, and no history of syphilis. Sensitivity analyses compared the TS-EIA and RPR, using the reference standard of concordantly positive/reactive TS-EIA/RPR or positive fluorescent treponemal antibody absorption test (FTA-ABS) result. We considered equivocal TS-EIA results to be positive for sensitivity calculations because such results typically reflex to additional testing and therefore may still result in identifying new infections.

RESULTS

Twenty-eight (53.8%) of the 52 patients had a positive or equivocal TS-EIA. Twenty-five (89.3%) of those were RPR reactive; the remaining 3 (10.7%) were RPR nonreactive, FTA-ABS positive. Forty patients (76.9%) had a positive RPR, including 15 patients (37.5%) with negative TS-EIA results; all 15 were FTA-ABS positive. Nine additional patients were TS-EIA negative and RPR nonreactive but had a positive FTA-ABS result. The RPR was significantly more sensitive than the EIA (76.9% vs. 53.8%, P = 0.005). Trep-Sure EIA positivity was also significantly associated with higher median RPR titer (P = 0.011).

CONCLUSIONS

Use of the TS-EIA may result in underdetection of primary syphilis compared with the RPR. Further evaluation of the sensitivity of the TS-EIA in high-morbidity settings is warranted before the adoption of reverse sequence screening algorithms.