Syphilis: review with emphasis on clinical, epidemiologic, and some biologic features

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.

Atypical Cutaneous Manifestations in Syphilis

Although the diversity of the clinical manifestations of syphilis is well-known, atypical presentations can also occur. Such atypical presentations are associated with a high risk of transmission as a result of diagnostic confusion and treatment delays owing to the disease's ability to mimic other common skin diseases, deviate from classic clinical presentations, and adopt unique forms. Cases of atypical syphilis have been described most frequently in patients with concomitant human immunodeficiency virus (HIV) infection. Because the incidence of syphilis has been growing over recent years -particularly in patients with HIV co-infection- dermatologists need to be familiar with the less well-known clinical presentations of this venereal disease.

Utility of immunochromatographic assay as a rapid point of care test for screening of antenatal syphilis

BACKGROUND AND OBJECTIVES

Syphilis is one of the most common preventable causes of adverse effects during pregnancy. Antenatal screening prevents the delay between diagnosis and treatment there by reducing the risk of congenital syphilis. The objective of this study was to evaluate the utility of an immunochromatographic assay as a point of care test for antenatal screening of syphilis.

MATERIALS AND METHODS

Sera of 200 antenatal mothers were evaluated for serodiagnosis of syphilis by the venereal disease research laboratory (VDRL), Treponema pallidum hemagglutination assay (TPHA) and SD BIOLINE Syphilis 3.0 test. The performance of SD BIOLINE Syphilis 3.0 test was compared with VDRL as screening assay and TPHA as a confirmatory test.

RESULTS

The antenatal prevalence of syphilis was found to be 2% by both VDRL and TPHA. The sensitivity, specificity, positive predictive value, and the negative predictive value of SD BIOLINE Syphilis 3.0 test were 75%, 100%, 100%, and 99.45%, respectively.

CONCLUSIONS

Antenatal screening and treatment of maternal syphilis are cost-effective health interventions even under the low prevalence of infection. SD BIOLINE Syphilis 3.0 test, although having less sensitivity than the existing testing strategy, can have a tremendous impact on the disease burden if used prudently for the screening of antenatal mothers in peripheral health settings.

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.

Syphilis hospitalisations in Portugal over the last decade

Although several studies have reported an increase of syphilis incidence over the last decade in Western Europe, information concerning syphilis epidemiology in Portugal remains scarce. Therefore, we sought to characterise acquired syphilis-associated hospitalisations in Portugal according to demographic and clinical data. We used a database containing all hospitalisations that occurred in mainland Portugal public hospitals with discharges between 2000 and 2014. We analysed all hospitalisations associated with ICD-9-CM codes 091-097.x (corresponding to acquired syphilis diagnosis) concerning inpatients' gender, age and comorbidities. The median length of stay and in-hospital mortality rates were also studied. Between 2000 and 2014, there were a total of 8974 syphilis-related hospitalisations in mainland Portugal. The rate of acquired syphilis hospitalisations per 100,000 inhabitants increased by 33 % during the studied period. Syphilis hospitalisation rates increased by 70 % in males and 139 % among patients aged over 55 years. On the other hand, they declined by 10 % in females and 20 % among patients younger than 55 years old. The percentage of syphilis episodes presenting cardiovascular and neuropsychiatric comorbidities increased, while the percentage of syphilis episodes presenting HIV co-infection decreased by 69 %. A fatal outcome was reported in 5 % of episodes; 4.6 % of them had acquired syphilis as the main reason for hospitalisation. This study illustrates that, despite being a preventable infection, syphilis remains a public health problem. The analysis of hospitalisation and administrative data helps to understand syphilis epidemiology and provides a supplement to traditional case notifications.

Rare presentation of ruptured syphilitic aortic aneurysm with pseudoaneurysm

We report the interesting case of a rare form of presentation of rupture of the ascending aorta with formation of a pseudoaneurysm, diagnosed following the development of a large mass on the surface of the chest over a period of about eight months. Serological tests were positive for syphilis. Echocardiography and computed tomography angiography were essential to confirm the diagnosis and therapeutic management. Cardiovascular syphilis is a rare entity since the discovery of penicillin. Rupture of an aortic aneurysm with formation of a pseudoaneurysm is a potentially fatal complication. The postoperative period was uneventful and the patient was discharged from hospital within days of surgery.

Factors associated with syphilis infection: a comprehensive analysis based on a case-control study

This study aimed to comprehensively evaluate factors that influence the likelihood of syphilis infection from risk-taking behaviours and medical conditions. A retrospective case-control study was conducted by enrolling 664 syphilis inpatients (excluding 11 congenital syphilis patients) and 800 sex- and age-matched controls. Medical histories, clinical data and patient interview data were collected and subjected to logistic regression analyses. The prevalence of syphilis in the study population was 3·9% (675/17,304). By univariate analysis, syphilis infection was associated with migration between cities, marital status, smoking, reproductive history, hypertension, elevated blood urea nitrogen (BUN) and infection with hepatitis B virus (HBV) (P < 0·05). A high rate of syphilis-HBV co-infection was observed in HIV-negative patients and further research revealed an association between syphilis and specific HBV serological reactivity. Syphilis was also associated with the frequency, duration and status of tobacco use. Multivariate analysis indicated that syphilis infection was independently associated with migration between cities [adjusted odds ratio (aOR) 1·368, 95% confidence interval (CI) 1·048-1·785], current smoking (aOR 1·607, 95% CI 1·177-2·195), elevated BUN (aOR 1·782, 95% CI 1·188-2·673) and some serological patterns of HBV infection. To prevent the spread of infectious diseases, inpatients and blood donors should be tested for HIV, syphilis, HBV and HCV simultaneously.

Clinical and pathologic diagnosis and different diagnosis of syphilis cervical lymphadenitis

PURPOSE

To study the clinical pathologic characteristics and differential diagnosis of syphilitic cervical lymphadenitis, and to improve the rate of its diagnosis and treatment.

METHODS

Retrospectively analyzed the clinical history, Trepone pallidum-ELISA (TP-ELISA), rapid plasma regain test (RPR) and routine pathological examination of the patient diagnosed as syphilis lymphadenitis. And review related literatures.

RESULTS

The main clinical presentation was multiple palpable cervical lymph nodes. The multiple nodes were hard, fixed, and the major diameter of the larger one was 2 cm. The main pathological changes included: the capsule was significantly thickened; reactive hyperplasia of lymphoid follicular with sky star phenomenon; occlusive endovasculitis; perivascular inflammation; the proliferation of epithelioid histiocytes can form granulomas with few multinucleated giant cells; few necrosis. TP-ELISA and RPR were positive.

CONCLUSIONS

The pathological changes of syphilitic lymphadenitis have a variety of performance with relatively specific and suggestive alterations which requires a combination of clinical history and laboratory test before the diagnosis, and the clinicians can reduce misdiagnosis and missed diagnosis of the disease by increasing vigilance of it.

[Syphilis and pregnancy]

Syphilis is a sexually transmitted disease responsible for a congenital severe infection. Congenital syphilis is complicated by fetal loss/neonatal death (50%), prematurity (25%) and major long term sequelae in other surviving children (20%). Every woman delivering a stillborn after 20WG should be tested for syphilis. Early screening is the cornerstone of prevention, and should be repeated in women at higher risk of contamination. Maternal management relies on early benzathine penicillin administration. Neonatal management relies on early diagnosis and prompt adequate penicillin therapy.

Neurosyphilis in HIV-infected patients

A review article is addressed the issue of the diagnosis and treatment of neurosyphilis that is developing against the background of HIV-infection. HIV-infected patients are at higher risk of neurologic, ocular and auricular manifestation of syphilis as well as treatment failures and relapses. Diagnosis of neurosyphilis in HIV-positive patients is complicated because both infections cause similar changes in the cerebrospinal fluid (CSF). The effectiveness of neurosyphilis treatment in patients with HIV co-infection is difficult to estimate, since the normalization of their CSF goes slower comparing to HIV-negatives. The increase in incidence of syphilis and HIV co-infection is anticipated in the coming years. This necessitates a comprehensive study of the problem and requires the development of new approaches to neurosyphilis diagnosis and treatment in co-infected patients.

Identification of functional candidates amongst hypothetical proteins of Treponema pallidum ssp. pallidum

Syphilis is a globally occurring venereal disease, and its infection is propagated through sexual contact. The causative agent of syphilis, Treponema pallidum ssp. pallidum, a Gram-negative sphirochaete, is an obligate human parasite. Genome of T. pallidum ssp. pallidum SS14 strain (RefSeq NC_010741.1) encodes 1,027 proteins, of which 444 proteins are known as hypothetical proteins (HPs), i.e., proteins of unknown functions. Here, we performed functional annotation of HPs of T. pallidum ssp. pallidum using various database, domain architecture predictors, protein function annotators and clustering tools. We have analyzed the sequences of 444 HPs of T. pallidum ssp. pallidum and subsequently predicted the function of 207 HPs with a high level of confidence. However, functions of 237 HPs are predicted with less accuracy. We found various enzymes, transporters, binding proteins in the annotated group of HPs that may be possible molecular targets, facilitating for the survival of pathogen. Our comprehensive analysis helps to understand the mechanism of pathogenesis to provide many novel potential therapeutic interventions.

Oral Secondary Syphilis

Secondary syphilis develops in approximately 25% of patients infected with the spirochete bacterium Treponema pallidum. It typically develops several weeks to several months after the primary infection, which is recognized by a painless chancre. Secondary syphilis is characterized by systemic symptoms, such as malaise and fever as well as a maculopapular rash involving the trunk and extremities including the palms and soles. Condyloma lata, which are raised, fleshy lesions, tend to develop at the site of the primary chancre. Diagnosis is achieved primarily through screening and confirmational serologic testing. Histologic findings seen in condyloma lata are largely non-specific. Therefore, a high index of suspicion should be maintained and immunohistochemical stains specific for T. pallidum should be utilized.

Neurosyphilis presenting with a stroke-like syndrome

Neurosyphilis results from infection of the central nervous system (CNS) by Treponema pallidum. Neurosyphilis can occur at any time after initial infection, particularly in immunocompromised patients. We describe a case of a 47-year-old man who presented with mixed dysphasia, right upper motor neuron facial palsy and right hemiparesis. Collateral history from the family revealed slowly progressive cognitive impairment and behavioural changes. Neuroimaging was unremarkable, suggesting a non-vascular aetiology. As there was no clear cause for the presentation, a lumbar puncture was performed and serum samples were sent for syphilis serology. The diagnosis of neurosyphilis was made on the basis of a positive RPR test in cerebrospinal fluid. The patient was treated with benzylpenicillin and made a full recovery, with restoration of cognitive function to baseline.

Evaluation of a new serological test for syphilis based on chemiluminescence assay in a tertiary care hospital

Context:

Syphilis is a transfusion transmissible infections and it is mandatory to do serological test for syphilis (STS) on all donor blood samples. STS is usually based on detection of antibodies against the cardiolipin-lecithin antigen or against the Treponema-specific antigen. STS with good sensitivity and specificity helps enhance blood safety and consolidation of STS along with other transfusion transmittable infections such as human immunodeficiency virus, hepatitis-C virus, and hepatitis-B virus helps in reducing the errors and enhances efficiency.

Aims:

This study was designed to evaluate the performance of newly introduced VITROS^® syphilis Treponema pallidum agglutination (TPA) assay based on enhanced chemiluminescence principle for its analytical performance for use as a STS on donor blood samples at a tertiary care health center in National Capital Region, India.

Materials and Methods:

A total of 108 random blood units collected from the donors (both voluntary and replacement donors) and 28 known syphilis sero-reactive samples stored at −20°C, were used to evaluate the performance of VITROS^® syphilis TPA assay based on enhanced chemiluminescence assay on VITROS^® ECiQ immunodiagnostics system along with its analytical performance in terms of its sensitivity, precision, cross-reactivity and interference studies.

Results:

VITROS^® syphilis TPA showed 100% sensitivity and specificity with precision (20 days study) of <10% co-efficient of variation. There was no cross-reactivity with other viral and auto-immune antibodies. No interference was observed from endogenous interfering substances like free hemoglobin or fats.

Conclusions:

Performance of the VITROS^® syphilis TPA assay meets the requirements for its use as STS in blood bank, thus allowing consolidation with other transfusion transmittable infections screening assay on chemiluminescence platform, which is highly valuable for optimizing workflow and efficiency.

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.

Utility of immunochromatographic assay as a rapid point of care test for screening of antenatal syphilis

BACKGROUND AND OBJECTIVES

Syphilis is one of the most common preventable causes of adverse effects during pregnancy. Antenatal screening prevents the delay between diagnosis and treatment there by reducing the risk of congenital syphilis. The objective of this study was to evaluate the utility of an immunochromatographic assay as a point of care test for antenatal screening of syphilis.

MATERIALS AND METHODS

Sera of 200 antenatal mothers were evaluated for serodiagnosis of syphilis by the venereal disease research laboratory (VDRL), Treponema pallidum hemagglutination assay (TPHA) and SD BIOLINE Syphilis 3.0 test. The performance of SD BIOLINE Syphilis 3.0 test was compared with VDRL as screening assay and TPHA as a confirmatory test.

RESULTS

The antenatal prevalence of syphilis was found to be 2% by both VDRL and TPHA. The sensitivity, specificity, positive predictive value, and the negative predictive value of SD BIOLINE Syphilis 3.0 test were 75%, 100%, 100%, and 99.45%, respectively.

CONCLUSIONS

Antenatal screening and treatment of maternal syphilis are cost-effective health interventions even under the low prevalence of infection. SD BIOLINE Syphilis 3.0 test, although having less sensitivity than the existing testing strategy, can have a tremendous impact on the disease burden if used prudently for the screening of antenatal mothers in peripheral health settings.

Rapid progression to gummatous syphilitic hepatitis and neurosyphilis in a patient with newly-diagnosed HIV

We review the literature on hepatic involvement in patients with HIV and syphilis co-infection and describe a case of rapid progression to neurosyphilis and presumed gummatous syphilitic hepatitis in a patient newly diagnosed with HIV. To our knowledge, this is the first case of syphilitic hepatitis with gummas described in the HIV population.

Serologic Testing for Syphilis: Benefits and Challenges of a Reverse Algorithm

Syphilis is a human infection of global importance. Its diagnosis can be challenging, requiring construction of a serologic profile based on the results of at least two types of antibody tests: treponemal and nontreponemal. The traditional approach to the serodiagnosis of syphilis has been the use of a nontreponemal screening assay followed by the performance of a treponemal confirmatory test if the initial nontreponemal screening test was reactive. With the increasing availability of automated, easier-to-perform, and rapid treponemal assays, an increasing number of laboratory testing sites are adopting reverse sequence screening for the serodiagnosis of syphilis: screening with a treponemal assay first, then confirmation with a nontreponemal assay and, when necessary, discrepant resolution using another treponemal test. In addition to offering automation and increased throughput, a reverse algorithm can increase disease detection, especially in late latent and early primary stages of infection when the nontreponemal antibody test may be nonreactive. However, a disadvantage to this approach is that there can be an increase in false-positive test results. This article reviews the clinical and workflow benefits and limitations of a reverse testing algorithm and discusses current guidance available from the Centers for Disease Control and Prevention.

Association between male circumcision and incidence of syphilis in men and women: a prospective study in HIV-1 serodiscordant heterosexual African couples

BACKGROUND

Male circumcision is a primary HIV-1 prevention intervention for men, but whether the procedure reduces the risk of syphilis among men and their female partners is uncertain. We aimed to assess whether male circumcision was associated with incident syphilis in men and in their female partners.

METHODS

In this large prospective cohort study, participants were members of Kenyan and Ugandan HIV-1 serodiscordant heterosexual couples enrolled in a randomised safety and efficacy clinical trial of pre-exposure prophylaxis for HIV-1 prevention (the Partners PrEP Study). Participants attended monthly or quarterly follow-up visits for up to 36 months. Annually, syphilis serology testing was done and male circumcision status was assessed. We used multivariate Andersen-Gill survival methods, adjusted for age, sexual behaviour, and plasma HIV RNA levels of the HIV-infected partner.

FINDINGS

4716 HIV-1 serodiscordant couples (38%) with a man with HIV were followed for a median of 2·75 years. At enrolment, 1575 (53%) men with HIV and 560 (32%) men without HIV were circumcised; an additional 69 (4%) men with HIV and 132 (5%) men without HIV were circumcised during study follow-up. 221 incident syphilis infections were reported: 46 (21%) in men with HIV (incidence 1·10 per 100 person-years), 76 (34%) in men without HIV (1·09), 54 (24%) in women with HIV (0·77), and 45 (24%) in women without HIV (1·11). Male circumcision was associated with a 42% reduction in incident syphilis in men (adjusted hazard ratio [aHR] 0·58, 95% CI 0·37-0·91) including a 62% reduction in men with HIV (0·38, 0·18-0·81), and a non-significant reduction in incident syphilis in men without HIV (0·64, 0·36-1·11). In women, circumcision of their male partners was associated with a 59% reduction in incident syphilis (aHR 0·41, 95% CI 0·25-0·69), including a 75% reduction in women without HIV (0·25, 0·08-0·76) and a 48% reduction in women with HIV (0·52, 0·27-0·97).

INTERPRETATION

Male circumcision was associated with decreased risk of incident syphilis in men and women. If confirmed, these results suggest that medical male circumcision could substantially reduce incidence of syphilis and its sequelae.

FUNDING

Bill & Melinda Gates Foundation and the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

The great imitator revisited: the spectrum of atypical cutaneous manifestations of secondary syphilis

Syphilis is a well-known sexually transmitted infection infamous for its protean cutaneous manifestations. Over the last decade, the rate of infection in the USA has risen, particularly among human immunodeficiency virus (HIV)-infected individuals and certain ethnic groups. Although the primary chancre developing at the site of inoculation usually has typical and well-characterized features, cutaneous manifestations of secondary syphilis span a wide spectrum and mimic those of other dermatoses. This may be particularly evident in patients with HIV. Such deviations from the expected typical papulosquamous eruption may present a diagnostic challenge and delay diagnosis and therapy. Given the increasing incidence of syphilis among the immunosuppressed patient population, recognition of atypical cutaneous manifestations is critical for adequate management. We review a range of cutaneous manifestations of secondary syphilis and the skin diseases it may mimic.

Neurosyphilis in a man with human immunodeficiency virus

The authors describe a 33-year-old man with human immunodeficiency virus who developed erythematous macules on the palms and soles with subsequent headaches, papilledema, and iritis. They review the salient characteristics of neurosyphilis with a focus on human immunodeficiency virus-positive individuals. The incidence of syphilis has increased since the year 2000 in African Americans, Hispanics, and men who have sex with men. Treponema pallidum is the causative agent of this disease-a fastidious, slowly growing, microaerophilic spirochete. Sexual contact is the most common mode of transmission. The rapid plasma reagin, Venereal Disease Research Laboratory assay, and fluorescent treponemal antibody absorption assay are commonly used to diagnose syphilis. The mainstay treatment is penicillin. Special considerations exist in the natural history and management of syphilis in the setting of human immunodeficiency virus.

Viscous dynamics of Lyme disease and syphilis spirochetes reveal flagellar torque and drag

The spirochetes that cause Lyme disease (Borrelia burgdorferi) and syphilis (Treponema pallidum) swim through viscous fluids, such as blood and interstitial fluid, by undulating their bodies as traveling, planar waves. These undulations are driven by rotation of the flagella within the periplasmic space, the narrow (∼20-40 nm in width) compartment between the inner and outer membranes. We show here that the swimming speeds of B. burgdorferi and T. pallidum decrease with increases in viscosity of the external aqueous milieu, even though the flagella are entirely intracellular. We then use mathematical modeling to show that the measured changes in speed are consistent with the exertion of constant torque by the spirochetal flagellar motors. Comparison of simulations, experiments, and a simple model for power dissipation allows us to estimate the torque and resistive drag that act on the flagella of these major spirochetal pathogens.

Cost-effectiveness of enhanced syphilis screening among HIV-positive men who have sex with men: a microsimulation model

BACKGROUND

Syphilis co-infection risk has increased substantially among HIV-infected men who have sex with men (MSM). Frequent screening for syphilis and treatment of men who test positive might be a practical means of controlling the risk of infection and disease sequelae in this population.

PURPOSE

We evaluated the cost-effectiveness of strategies that increased the frequency and population coverage of syphilis screening in HIV-infected MSM receiving HIV care, relative to current standard of care.

METHODS

We developed a state-transition microsimulation model of syphilis natural history and medical care in HIV-infected MSM receiving care for HIV. We performed Monte Carlo simulations using input data derived from a large observational cohort in Ontario, Canada, and from published biomedical literature. Simulations compared usual care (57% of the population screened annually) to different combinations of more frequent (3- or 6-monthly) screening and higher coverage (100% screened). We estimated expected disease-specific outcomes, quality-adjusted survival, costs, and cost-effectiveness associated with each strategy from the perspective of a public health care payer.

RESULTS

Usual care was more costly and less effective than strategies with more frequent or higher coverage screening. Higher coverage strategies (with screening frequency of 3 or 6 months) were expected to be cost-effective based on usually cited willingness-to-pay thresholds. These findings were robust in the face of probabilistic sensitivity analyses, alternate cost-effectiveness thresholds, and alternate assumptions about duration of risk, program characteristics, and management of underlying HIV.

CONCLUSIONS

We project that higher coverage and more frequent syphilis screening of HIV-infected MSM would be a highly cost-effective health intervention, with many potentially viable screening strategies projected to both save costs and improve health when compared to usual care. The baseline requirement for regular blood testing in this group (i.e., for viral load monitoring) makes intensification of syphilis screening appear readily practicable.

[Evaluation of the serological response to syphilis treatment using an automated RPR test]

We evaluated the clinical usefulness of serological monitoring with an automated rapid plasma reagin (RPR) test in syphilis patients. Serum samples were obtained from 68 syphilis patients, including 57 cases infected with human immunodeficiency virus (HIV) from our clinic between February 2010 and May 2012. RPR titers were measured with both the conventional serial dilution manual method and the automated method before (baseline) and at several intervals after treatment. The criteria of a cure were defined based on RPR titers as equal to and/or more than a 4-fold decrease (with the manual method) or by RPR values lowered to the level of equal and/or less than 25% (with the automated method) within 6 months in comparison with baseline values. A serological cure was observed in 19 (95%) and 17 (85%) of the 20 cases with the manual method and the automated method after 6 months, respectively. For the other 3 cases, the RPR value ratios with the automated method were 25.4%, 25.9% and 37.9%. Among all 68 patients, 9 cases (13.2%) did not meet the criteria for a cure by both methods within 6 months, but all cases did within 12 months. The ratio of RPR values after several months against that of baseline was evaluated with a t-test; the RPR values with the automated method were significantly lower than those obtained with the manual method (p < 0.05), especially at 1 and 2 months (p < 0.01). The RPR value ratios of HIV-positive cases were significantly higher 1 and 2 months after (with the manual method) and 1 month after (with the automated method) than those of HIV-negative cases; however, no statistical significance was observed after 6 months between the RPR ratio of HIV-positive and HIV-negative cases. Based on these results, we infer that the RPR test with the automated method can be used in the same manner as the manual method for treatment monitoring of HIV-positive and HIV-negative syphilis patients, especially in the early phase of treatment.

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

BACKGROUND

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

AIMS

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

METHODS

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

RESULTS

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

DISCUSSION

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

CONCLUSION

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

Demographic, risk factors and motivations among blood donors with reactive serologic tests for syphilis in São Paulo, Brazil

OBJECTIVE

To identify the demographic characteristics, risk factors and motivations for donating among blood donors with reactive serologic tests for syphilis.

BACKGROUND

Post-donation interviews with syphilis seropositive blood donors improve recruitment and screening strategies.

METHODS

This case-control study compares 75 Venereal Disease Research Laboratory (VDRL) > 8, EIA+ (enzyme immunoassay) and FTA-ABS+ (fluorescent treponemal antibody); 80 VDRL-, EIA+ and FTA-ABS+; and 34 VDRL- and EIA- donors between 2004 and 2009. Donors were assessed by their demographic characteristics, sexual behaviour, history of alcohol and illicit drugs use, and motivations to donate.

RESULTS

Donors with VDRL > 8 were more likely to be divorced [AOR = 12·53; 95% confidence interval (CI) 1·30-120·81], to have had more than six sexual partners (AOR=7·1; 95% CI 1·12-44·62) and to report male-male-sex in the past 12 months (AOR=8·18; 95% CI 1·78-37·60). Donors with VDRL-, EIA+ and FTA-ABS+ were less likely to be female (AOR=0·26; 95% CI 0·07-0·96), more likely to be older (AOR=10·2; 95% CI 2·45-42·58 ≥ 39 and <60 years old) and to have had more than six sexual partners in the past 12 months (AOR = 8·37; 95% CI 1·49-46·91). There was no significant difference among groups regarding illicit drugs use; 30·7% (VDRL > 8) and 12·5% (VDRL-, EIA+ and FTA-ABS+) of donors reported that they had been at risk for HIV infection (P = 0·004). One-third of donors came to the blood bank to help a friend or a relative who needed blood.

CONCLUSION

Although donors exposed to syphilis reported and recognised some high risk behaviour, most were motivated by direct appeal to donate blood. Monitoring the risk profile of blood donors can benefit public health and improve blood safety.

Brief history of syphilis

Before the discovery of Treponema pallidum as the etiologic agent, the origins of syphilis have been the subject of several debates. Diverse therapeutic agents were employed in an attempt to cure the disease. Examining the milestones in the history of syphilis, the present article reviews the existing theories that tried to explain the origins of the disease, the approach in art, the cultural and the evolution of the treatments from the empiric means to the discovery of penicillin.

Comparison of a combined nontreponemal (VDRL) and treponemal immunoblot to traditional nontreponemal and treponemal assays

BACKGROUND

Serology is the mainstay for the diagnosis and management of patients with syphilis. Newer technologies such as immunoblotting are now available for the diagnosis of syphilis.

METHODS

A commercial IgM/IgG immunoblot assay that detects both nontreponemal (VDRL-Venereal Disease Research Laboratory) and treponemal antibodies was compared with standard nontreponemal and treponemal assays. The immunoblot and T. pallidum particle agglutination assay (TP-PA) were performed on 198 samples. Ninety-seven samples were Rapid plasma reagin (RPR)-positive and one hundred one were RPR-negative. Positive RPR samples were titered by VDRL.

RESULTS

The agreement, sensitivity, and specificity of the IgM/IgG VDRL results of the immunoblot compared to RPR were 74.2% (95% CI: 67.2-80.2), 77.3% (95% CI: 70.2-83.4), and 71.3% (95% CI: 64.4-77.1), respectively. The agreement, sensitivity, and specificity of the IgM/IgG treponemal immunoblot compared to TP-PA were 100% for all parameters, if the ten equivocal results were not used in the calculation.

CONCLUSION

The treponemal portion of the ViraBlot IgM/IgG immunoblot compared well with the treponemal confirmation assay and could be a useful supplemental method to fluorescent treponemal antibody or TP-PA for the confirmation of syphilis. The addition of the detection of nontreponemal antibodies to the immunoblot assay, however, may not be of added benefit to the overall assay, due to decreased sensitivity and specificity compared to standard assays.

Evaluation of rapid syphilis tests in KwaZulu-Natal

BACKGROUND

Despite the considerable decrease in the seroprevalence of syphilis in South Africa, with an estimated prevalence of 1.5% in 2010, the disease remains a threat particularly to pregnant women, hence there is a need for a rapid, reliable, and affordable screening and diagnostic test. A laboratory evaluation study was conducted in response to a call by the KwaZulu-Natal (KZN) Provincial Department of Health that is considering using rapid point-of-care syphilis tests.

METHODS

The performances of the Hexagon and the SD Bioline syphilis tests were compared with the Treponema pallidum hemagglutination assay (TPHA) reference test using 297 (142 positive and 155 negative) serum specimens.

RESULTS

Both assays demonstrated good performance with negative and positive concordance of 97 and 94% for the Hexagon assay and 98 and 90% for SD Bioline assay, respectively, when compared to the TPHA. The Hexagon test was quicker and easier to read than the SD Bioline test.

CONCLUSION

Although the rapid syphilis tests performed favorably, a number of issues need to be considered prior to their use for syphilis screening in the public sector of South Africa.

Prevalence and associated risk factors for syphilis in women with recurrent miscarriages

OBJECTIVE

A Cross Sectional population based serological studies was conducted to determine the prevalence and associated risk factors for syphilis women with recurrent miscarriages.

METHODS

Patient's 5ml whole blood was collected through venepuncture technique. Data were collected by all women answered a questionnaire and by investigating blood sample VDRL test and FTA-ABS test. The study was conducted in a confidential manner and numbers were used to identify the participant.

RESULTS

Total 256 women were included in the present study. Mean age of women was 29.4 years while range was 21 to 38 years (206/256). Out of the 256 samples, 05 (1.9%) were positive for active syphilis. Majority belonged to low socioeconomic group, uneducated and had previous congenital anomaly.

CONCLUSION

Active infection with Treponema pallidum (T.P) in women belonging to low socioeconomic level were disquieting. This is probably due to illiteracy and high proportion of unsafe sexual behavior. It is also suggestive that seropositive status is often discovered in routine serological studies during pregnancy.

Use of cerebrospinal fluid enzyme immunoassay for diagnosis of neurosyphilis

Summary

Neurosyphilis is a difficult clinical stage of syphilis as there is no ideal method for diagnosis and workup requires lumbar puncture which may sometimes provide ambiguous results especially in HIV co-infected patients. Enzyme immunoassay is a widely used screening test for syphilis in serum, but its test performance was not well studied in cerebrospinal fluid. To examine the diagnostic performance of cerebrospinal fluid-enzyme immunoassay (CSF-EIA) in neurosyphilis, we conducted a prospective study for two years. All consecutive patients admitted for workup of neurosyphilis under the Social Hygiene Service, in Hong Kong, were included. Laboratory tests on CSF included several serological tests, CSF cell count, and protein. Forty-five patients were prospectively recruited, of which 29 people were living with HIV / AIDS. Using diagnostic case definition standard stipulated in the IUSTI 2008 guidelines, 17 patients satisfied the diagnosis of neurosyphilis. The CSF-EIA test provided 100% in both sensitivity and negative predictive value; its specificity was 46.4% (13/28, 95% CI 31.8–61%). Specificity improved to 80.8% (95% CI: 68.4–93.2%) with optical density cut-off value at 1.4 for cases with CSF red cell counts <600/mm3. This is the first study on use of CSF-EIA in neurosyphilis. CSF-EIA showed high sensitivity and high negative predictive value in the study population and the presence of CSF red cells < 600/mm3 might not affect its accuracy.

Temporal trends in syphilis and gonorrhea incidences in guangdong province, china

The high burden of syphilis in China presents a unique opportunity to examine temporal trends. This study used wavelet transformation and Fourier analysis to assess the presence of temporal oscillations in the incidence of syphilis among adults, gonorrhea, and congenital syphilis over 11 years in China's largest province. This study found a significant annual oscillation trend in the incidence of adult syphilis, consistent with a peak during July-September, which was 4-fold higher than the trough, which occurred during January-March. A similar but dampened trend was observed in the incidence of gonorrhea, and no trend was observed for the incidence of congenital syphilis. Further research on the temporal oscillation of the incidence of syphilis is needed.

Usefulness of (18)F-FDG PET/CT in disease extent and treatment response assessment in a patient with syphilitic aortitis

A 40-year-old man was admitted to our hospital for surgical treatment of aortic insufficiency and coronary ostial stenosis. Histopathology and serological tests revealed a syphilitic aortitis. F-FDG PET/CT was performed to assess the extent of aortitis, showing increased radiopharmaceutical uptake along the ascending aortic wall. A repeated FDG PET/CT after antibiotic therapy showed a markedly reduced uptake in the aortic wall, suggesting resolution of the infection according to clinical and serological data. This case highlights the usefulness of FDG PET/CT for the assessment of disease extent and treatment response in patients with syphilitic aortitis.

A complex neurological presentation of syphilis

Syphilis is a contagious sexually transmitted infection notable for its complex array of systemic presentations. It is caused by the spirochaete Treponema pallidum and although once considered to be a largely historical condition in the UK, the recent rise in incidence makes syphilis increasingly relevant when considering unusual presentations in at-risk patients. The disease has three stages: primary, secondary and tertiary. The tertiary stage is associated with a plethora of neurological features ranging from psychosis to seizure caused by direct invasion of the spirochaete into the central nervous system. Here we describe the case of a 45-year-old man presenting with tonic clonic seizures on a background of balance and visual problems. Following normal examination and routine investigations further serology confirmed a diagnosis of neurosyphilis. The patient was started on appropriate treatment and made an excellent clinical recovery.

Enhanced surveillance of infectious syphilis in New Zealand sexual health clinics

Following a rise in cases of infectious syphilis in New Zealand, national enhanced surveillance at sexual health clinics was initiated. All public sexual health clinics reported monthly on the number of cases seen, and completed a coded questionnaire on each case. Monthly reports to routine surveillance were compared and discrepancies reconciled. During 2011, 72 cases of infectious syphilis were reported. The majority (83%) were among men who have sex with men who were mainly infected in New Zealand and had an ethnic profile similar to all New Zealanders. Most heterosexual infections occurred overseas, among people of non-European non-Maori ethnicity. About half the cases had symptoms on presentation. Overall, 18% of men who have sex with men were HIV positive. Resurgent syphilis in New Zealand disproportionally affects men who have sex with men, amongst whom HIV is prevalent. Men who have sex with men should be aware of the risks and symptoms of syphilis and encouraged to have regular sexual health checks including serology testing. Control of syphilis should be included in the strategy to check HIV spread. Syphilis serology should continue to be part of routine immigration and antenatal screening, and where clinically indicated. Enhanced surveillance was easily initiated for an uncommon condition seen at sexual health clinics, and provided valuable information.

Unilateral swollen optic disc: do not forget neurosyphilis

A 51-year-old man presented with a 3 month history of progressive right visual loss. On examination, the only abnormal findings were a right visual acuity of 4/10 and a swollen right optic disc. The patient had previously undergone MRI that had been reported as being normal and a trial of corticosteroids under the care of the referring ophthalmologist. An extensive battery of blood tests was normal apart from a rapid plasmatic reagin titre of 1:64. ELISA revealed elevated levels of total and immunoglobulin M antibodies against Treponema pallidum. Cerebrospinal fluid analysis revealed a mild leucocytosis and mildly elevated protein content. The patient was treated with a 5 week course of penicillin. Three months after starting treatment, his right visual acuity had improved to 8/10 and his right optic disc swelling had resolved.

Prevalence of positive syphilis serology and meningovascular neurosyphilis in patients admitted with stroke and TIA from a culturally diverse population (2005-09)

The study aims were to determine the prevalence of positive syphilis serology and meningovascular neurosyphilis (NS) in patients admitted with transient ischaemic attack (TIA) and stroke to a tertiary hospital serving a culturally diverse community. A retrospective cohort analysis was conducted using routinely collected administrative data and medical records to identify patients admitted with TIA, stroke and other conditions, with positive syphilis serology, between 2005 and 2009. Direct medical record review confirmed diagnoses of meningovascular NS. Syphilis serology was requested in 27% (893/3270) of all patients with TIA and stroke (2005-09) of whom 4% (38/893) were positive. Thirty-seven patients with positive serology had clinical characteristics consistent with meningovascular NS. Their mean age was 72±13 years; 65% were male and 68% had a recorded place of birth in South-East Asia or the Pacific Islands. One of 12 patients with suspected meningovascular NS with cerebrospinal fluid (CSF) analysis had a positive CSF Venereal Disease Research Laboratory (VDRL) test. Three patients (8%) met diagnostic criteria for "definite or probable" meningovascular NS. All three patients with a "definite or probable" meningovascular NS and 15 (44%) of the remainder who had positive serology without confirmation of NS were treated with intravenous or intramuscular penicillin. Lumbar puncture (LP) and penicillin were underutilised in patients with TIA and stroke with positive serology. In conclusion, syphilis testing should be considered part of the diagnostic work-up of TIA and stroke, particularly in ethnically diverse populations. In patients with TIA and stroke with positive syphilis serology, it would seem appropriate to further pursue diagnosis and treatment and in patients unable to undergo LP, empiric treatment for NS should be considered.

Screen more or screen more often? Using mathematical models to inform syphilis control strategies

Background

Syphilis incidence among men who have sex with men (MSM) continues to rise despite attempts to increase screening and treatment uptake. We examined the marginal effect of increased frequency versus increased coverage of screening on syphilis incidence in Toronto, Canada.

Methods

We developed an agent-based, network model of syphilis transmission, representing a core population of 2,000 high-risk MSM. Epidemiological and biological parameters were drawn from regional surveillance data and literature-derived estimates. The pre-intervention period of the model was calibrated using surveillance data to identify 1000 credible simulations per strategy. Evaluated strategies included: annual syphilis screening at baseline coverage, increased screening frequency at baseline coverage, and increased coverage of annual screening. Intervention impact was measured as annual prevalence of detected infectious cases and syphilis incidence per year over 10 years.

Results

Of the strategies evaluated, increasing the frequency of syphilis screening to every three months was most effective in reducing reported and incident syphilis infections. Increasing the fraction of individuals tested, without increasing test frequency, resulted a smaller decline in incidence, because reductions in infectious syphilis via treatment were counterbalanced by increased incident syphilis among individuals with prior latent syphilis. For an equivalent number of additional tests performed annually, increased test frequency was consistently more effective than improved coverage.

Conclusions

Strategies that focus on higher frequency of testing in smaller fractions of the population were more effective in reducing syphilis incidence in a simulated MSM population. The findings highlight how treatment-induced loss of immunity can create unexpected results in screening-based control strategies.

Evaluation of a new chemiluminescence immunoassay for laboratory diagnosis of syphilis

The purpose of this study was to evaluate diagnostic performances of automated chemiluminescence immunoassay (CLIA) in comparison with Treponema pallidum hemagglutination test (TPHA). The specificity of CLIA was 98.9% and 99.6% for TPHA, whereas the sensitivity was 98% and 96%, respectively. Considering the suitability for automation, CLIA may represent a suitable alternative.