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Concept: Treponema pallidum


BACKGROUND: Serologic tests are widely used for the diagnosis of syphilis. However, conventional methods require well-trained technicians to produce reliable results. We compared automated nontreponemal and treponemal tests with conventional methods. METHODS: The HiSens Auto Rapid Plasma Reagin (AutoRPR) and Treponema Pallidum Particle Agglutination (AutoTPPA) tests, which utilize latex turbidimetric immunoassay, were assessed. A total of 504 sera were assayed by AutoRPR, AutoTPPA, conventional VDRL and FTA-ABS. Among them, 250 samples were also tested by conventional TPPA. RESULTS: The concordance rate between the results of VDRL and AutoRPR was 67.5%, and 164 discrepant cases were all VDRL reactive but AutoRPR negative. In the 164 cases, 133 showed FTA-ABS reactivity. Medical records of 106 among the 133 cases were reviewed, and 82 among 106 specimens were found to be collected from patients already treated for syphilis. The concordance rate between the results of AutoTPPA and FTA-ABS was 97.8%. The results of conventional TPPA and AutoTPPA for 250 samples were concordant in 241 cases (96.4%). AutoRPR showed higher specificity than that of VDRL, while VDRL demonstrated higher sensitivity than that of AutoRPR regardless of whether the patients had been already treated for syphilis or not. Both FTA-ABS and AutoTPPA showed high sensitivities and specificities greater than 98.0%. CONCLUSIONS: Automated RPR and TPPA tests could be alternatives to conventional syphilis tests, and AutoRPR would be particularly suitable in treatment monitoring, since results by AutoRPR in cases after treatment became negative more rapidly than by VDRL.

Concepts: Sensitivity and specificity, Syphilis, Blood tests, Spirochaete, Treponema pallidum, Treponema, FTA-ABS, Rapid plasma reagin


Ocular syphilis, a manifestation of Treponema pallidum infection, can cause a variety of ocular signs and symptoms, including eye redness, blurry vision, and vision loss. Although syphilis is nationally notifiable, ocular manifestations are not reportable to CDC. Syphilis rates have increased in the United States since 2000. After ocular syphilis clusters were reported in early 2015, CDC issued a clinical advisory (1) in April 2015 and published a description of the cases in October 2015 (2). Because of concerns about an increase in ocular syphilis, eight jurisdictions (California, excluding Los Angeles and San Francisco, Florida, Indiana, Maryland, New York City, North Carolina, Texas, and Washington) reviewed syphilis surveillance and case investigation data from 2014, 2015, or both to ascertain syphilis cases with ocular manifestations. A total of 388 suspected ocular syphilis cases were identified, 157 in 2014 and 231 in 2015. Overall, among total syphilis surveillance cases in the jurisdictions evaluated, 0.53% in 2014 and 0.65% in 2015 indicated ocular symptoms. Five jurisdictions described an increase in suspected ocular syphilis cases in 2014 and 2015. The predominance of cases in men (93%), proportion of those who are men who have sex with men (MSM), and percentage who are HIV-positive (51%) are consistent with the epidemiology of syphilis in the United States. It is important for clinicians to be aware of potential visual complications related to syphilis infections. Prompt identification of potential ocular syphilis, ophthalmologic evaluation, and appropriate treatment are critical to prevent or manage visual symptoms and sequelae of ocular syphilis.

Concepts: United States, U.S. state, Ophthalmology, Syphilis, New York City, North Carolina, Los Angeles, Treponema pallidum


The growing shale gas (“fracking”) industry depends on a mobile workforce, whose influx could have social impacts on host communities. Sexually transmitted infections (STIs) can increase through sexual mixing patterns associated with labor migration. No prior studies have quantified the relationship between shale gas activity and rates of three reportable STIs: chlamydia, gonorrhea, and syphilis.

Concepts: Oral sex, Sexually transmitted disease, Human sexual behavior, Chlamydia infection, Syphilis, Sexually transmitted diseases and infections, Neisseria gonorrhoeae, Treponema pallidum


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.

Concepts: Medical terms, Infection, Sexually transmitted disease, Syphilis, Spirochaetes, Spirochaete, Treponema pallidum, Treponema


The human treponematoses comprise venereal syphilis and the three non-venereal or endemic treponematoses yaws, bejel, and pinta. Serological assays remain the most common diagnostic method for all treponemal infections. Point-of-care tests (POCTs) for syphilis and yaws allow testing without further development of infrastructure in populations where routine laboratory facilities are not available. Alongside the test’s performance characteristics assessed through diagnostic evaluation, it is important to consider broader issues when rolling out a POCT. Experience with malaria POCT roll-out in sub-Saharan Africa has demonstrated that both healthcare worker and patient beliefs may play a major role in shaping the real-world use of POCTs. We conducted a qualitative study evaluating healthcare worker and patient perceptions of using a syphilis/yaws POCT in clinics in the East Malaita region of Malaita province in the Solomon Islands. Prior to the study serology was only routinely available at the local district hospital.

Concepts: Malaria, Africa, Syphilis, Treponema pallidum, Pinta, Bejel, Yaws, Malaita


Recently, the World Health Organization launched a campaign to eradicate the tropical disease yaws, caused by the bacterium Treponema pallidum subsp. pertenue; however, for decades researchers have questioned whether flies act as a vector for the pathogen that could facilitate transmission.

Concepts: Epidemiology, Bacteria, Biodiversity, Malaria, Ecosystem, Syphilis, World Health Organization, Treponema pallidum


Treponema pallidum ssp. pallidum (TPA), the causative agent of syphilis, and Treponema pallidum ssp. pertenue (TPE), the causative agent of yaws, are closely related spirochetes causing diseases with distinct clinical manifestations. The TPA Mexico A strain was isolated in 1953 from male, with primary syphilis, living in Mexico. Attempts to cultivate TPA Mexico A strain under in vitro conditions have revealed lower growth potential compared to other tested TPA strains.

Concepts: DNA, Insect, In vitro, Syphilis, Spirochaetes, Spirochaete, Treponema pallidum, Treponema


Treponema pallidum subspecies pallidum (T. pallidum) causes syphilis via sexual exposure or via vertical transmission during pregnancy. T. pallidum is renowned for its invasiveness and immune-evasiveness; its clinical manifestations result from local inflammatory responses to replicating spirochaetes and often imitate those of other diseases. The spirochaete has a long latent period during which individuals have no signs or symptoms but can remain infectious. Despite the availability of simple diagnostic tests and the effectiveness of treatment with a single dose of long-acting penicillin, syphilis is re-emerging as a global public health problem, particularly among men who have sex with men (MSM) in high-income and middle-income countries. Syphilis also causes several hundred thousand stillbirths and neonatal deaths every year in developing nations. Although several low-income countries have achieved WHO targets for the elimination of congenital syphilis, an alarming increase in the prevalence of syphilis in HIV-infected MSM serves as a strong reminder of the tenacity of T. pallidum as a pathogen. Strong advocacy and community involvement are needed to ensure that syphilis is given a high priority on the global health agenda. More investment is needed in research on the interaction between HIV and syphilis in MSM as well as into improved diagnostics, a better test of cure, intensified public health measures and, ultimately, a vaccine.

Concepts: Public health, Epidemiology, Disease, Syphilis, Spirochaetes, Spirochaete, Treponema pallidum, Treponema


Treponema pallidum subsp. pallidum, the causative agent of syphilis, is a highly invasive spirochete pathogen that uses the vasculature to disseminate throughout the body. Identification of bacterial factors promoting dissemination is crucial for syphilis vaccine development. An important step in dissemination is bacterial adhesion to blood vessel surfaces, a process mediated by bacterial proteins that can withstand forces imposed on adhesive bonds by blood flow (vascular adhesins). The study of T. pallidum vascular adhesins is hindered by the uncultivable nature of this pathogen. We overcame these limitations by expressing T. pallidum adhesin Tp0751 (pallilysin) in an adhesion-attenuated strain of the cultivable spirochete Borrelia burgdorferi. Under fluid shear stress representative of conditions in postcapillary venules, Tp0751 restored bacterial-vascular interactions to levels similar to those observed for infectious B. burgdorferi and a gain-of-function strain expressing B. burgdorferi vascular adhesin BBK32. The strength and stability of Tp0751- and BBK32-dependent endothelial interactions under physiological shear stress were similar, although the mechanisms stabilizing these interactions were distinct. Tp0751 expression also permitted bacteria to interact with postcapillary venules in live mice as effectively as BBK32-expressing strains. These results demonstrate that Tp0751 can function as a vascular adhesin.

Concepts: Bacteria, Blood vessel, Lyme disease, Borrelia burgdorferi, Borrelia, Spirochaetes, Spirochaete, Treponema pallidum


To develop a tool for estimating national trends in adult prevalence of sexually transmitted infections by low- and middle-income countries, using standardised, routinely collected programme indicator data.

Concepts: Computer program, Sexually transmitted disease, Human sexual behavior, Chlamydia infection, Syphilis, Sexually transmitted diseases and infections, Neisseria gonorrhoeae, Treponema pallidum