Epidemiological characteristics of syphilis in mainland China, 2004 to 2019.

OBJECTIVES: Syphilis is a globally prevalent sexually transmitted infection. This study aimed to elucidate the epidemiological characteristics of syphilis in China from 2004 to 2019. METHODS: Incidence data for syphilis across 31 provinces in mainland China were obtained from the Data Center of China Public Health Science for the period from 2004 to 2019. Epidemiological methods and the Chi-squared test were used to analyze the temporal, regional, and disease stage distributions of syphilis. RESULTS: In total, 5,527,399 syphilis cases were reported in China from 2004 to 2019, with an average annual prevalence of 25.7063 per 100,000 population and overall increasing trend. In terms of regional distribution, high-incidence provinces included Shanghai, Zhejiang, Fujian, Guangxi, Guangdong, Xinjiang, Ningxia, and Qinghai. The proportion of latent syphilis increased from 20.41% in 2004 to 82.95% in 2019, with an upward trend each year. CONCLUSIONS: Syphilis incidence exhibited an overall increasing trend in China, and latent syphilis was predominant. Syphilis incidences considerably varied among regions, and syphilis was detected from coastal to inland provinces. Thus, syphilis prevention and control programs should be tailored according to the specific epidemiological characteristics of each region.

A network suspected infectious disease model for the development of syphilis transmission from 2015 to 2021 in Hubei province, China.

AIMS: Understanding the transmission mode of syphilis is essential to prevent and predict its future prevalence and to develop effective control measures. This study aimed to develop a network suspected infectious disease model to simulate the syphilis transmission. METHODS AND RESULTS: The number of syphilis cases in Wuhan's Fourth Hospital, Hubei province, China, from October 2015 to July 2021 was collected. The simulation was carried out by interpersonal network-SI (suspected infectious) model based on temporal exponential family random graph models. Late latent syphilis and tertiary syphilis are predicted by December 2025. The validity of simulated value and real data was tested, including determination coefficient (R2), root means square error (RMSE), and means relative error (MRE). Moreover, we developed an online app that can more easily predict the number of syphilis infections in different scenarios by setting different parameters. Results showed that R2, RMSE, and MRE were 0.995, 36.19, and 6.31, respectively. Speed from latent infection to primary syphilis, primary syphilis to secondary syphilis, and susceptible group to latent infection decreased rapidly. The speed of transformation from secondary syphilis to early incubation period and early latent to late latent experienced a process from increase to decreased. Late latent to tertiary syphilis patients increased steadily. The number of late latent patients, early latent, invisible infection, primary syphilis, and secondary syphilis all increased at first and turn to decreased. However, tertiary syphilis continuously kept rising in the whole process. To better make use of the transmission model, an online application was developed (https://alanwu.shinyapps.io/MD-shiny/). CONCLUSIONS: Based on the simulation that late latent and tertiary syphilis were steadily increasing, the prevention and treatment for syphilis were imperative.

The treatment outcome and predictors of serological response in syphilis in a sexually transmitted infections center, China.

Serology is the mainstay for syphilis treatment monitoring. Baseline rapid plasma reagin (RPR) titre, HIV status, and syphilis stage have been found to be associated with the time to serological response among syphilis patients. This study mainly aims to evaluate the time to serological response, and to identify factors affecting the serological outcome. Medical records of syphilis cases diagnosed in Peking Union Medical College Hospital (PUMCH) between 2008 and 2018 were retrospectively reviewed. Kaplan-Meier analysis was performed to evaluate the median time to serologic response and cumulative probability of serologic response over time according to different variables. Cox regression model was conducted to find factors associated with serological response. There were 984 patients diagnosed with primary, secondary, or latent syphilis cases and receiving injections of benzathine penicillin G (BPG) as initial treatment at the Peking Union Medical College Hospital (PUMCH) between 2008 and 2018. Finally, data on 571 patients, including 49 (8.6%) primary syphilis, 261 (45.7%) secondary syphilis, and 261 (45.7%) latent syphilis, were used for analysis. It took longer time to achieve serological response for subjects aged ≥45 years than younger individuals (89 days versus 58 days; p=0.008). Males achieved serological response more quickly than females (71 days versus 83 days; p = 0.011). There was a significant difference in the time to serological response according to different syphilis stages (p < 0.001), with 55 days (95% CI, 43-67 days) for primary, 57 days (95% CI, 51-63 days) for secondary, and 117 days for latent syphilis. In addition, patients with lower baseline RPR titre had longer period to achieve serological response (252 days [95% CI, 129-375 days] for RPR titre ≤1:8, 78 days [95% CI, 63-93 days] for RPR titres from 1:16 to 1:32, and 53 days [95% CI, 49-57 days] for RPR titres ≥1:64, respectively; p<0.001). However, no significant difference in time to serological response to treatment was found according to HIV coinfection status. The result of multivariate Cox regression analysis showed that being older than 45 years with latent syphilis, HIV coinfection, or with baseline RPR titre ≤1:8 was associated with slow response. Among patients followed for at least 1 year or seroreverted, 128 (36.9%) had seroreverted within a year, and 219 (63.1%) still had a positive RPR after 1 year. For multiple logistical regression, being female and HIV coinfection were significantly associated with the failure of seroreversion (OR, 0.42 [95% CI, 0.26-0.68]; p <0.001). This study revealed that younger age, higher initial RPR titre, early syphilis stage, and HIV-negative status were associated with faster serological cure. Female sex, individuals with HIV coinfection, and latent syphilis were significantly associated with the failure of seroreversion.

The Epidemiological and Clinical Characteristics of the Epidemic of Syphilis in Barcelona. / Las características epidemiológicas y clínicas de la epidemia de sífilis en Barcelona.

BACKGROUND: Since 2000, substantial increases in syphilis have been reported in metropolitan areas of Western countries, with increases noted among men who have sex with men (MSM). Clinical manifestations of syphilis might be influenced by concomitant VIH infection and previous episodes of syphilis. The objectives of this study were to describe the epidemiological and clinical characteristics of the cases of syphilis diagnosed in Barcelona. METHODS: Retrospective study of cases with early syphilis diagnosed in the referral STI Unit of Barcelona from January 2003 to December 2013. Revision of medical records with structured collection of epidemiological and clinical data. Univariate and multivariate statistical analyses comparing the characteristics of MSM cases with and without VIH infection and with and without previous syphilis. RESULTS: A total of 1702 cases of syphilis (37% primary, 48% secondary and 14% early latent) were diagnosed, 93% of them in MSM. Among MSM 40% were coinfected with VIH, VIH-positive cases were associated with a previous syphilis (aOR, 5.2 [95% CI, 3.32-8.24]) and with unprotected anal intercourse (aOR, 1.75 [95%CI, 1.17-2.63]). Cases with a history of syphilis presented less often with primary syphilis compared to those without it (27.5% vs. 40%) (aOR, 0.58 [95% CI, 0.44-0.77]). One year after treatment, the clinical and serological evolution were similar between VIH-positive and VIH-negative cases. CONCLUSION: The epidemic of syphilis in Barcelona disproportionately affects MSM and is closelly linked to VIH infection. The presentation of syphilis is influenced by VIH infection and by previous history of syphilis, without significant differences in their evolution after one year of treatment.

Perfil epidemiológico de sífilis congénita en una microrregión en el interior del estado de Bahia (2007-2017) / Epidemiological profile of congenital syphilis in a microregion inside the state of Bahia (2007-2017) / Perfil epidemiológico da sífilis congênita em uma microrregião no interior do estado da Bahia (2007-2017)

Objetivo: Analizar el perfil epidemiológico de Sífilis Congénita en 18 municipios en el interior del estado de Bahía entre 2007 y 2017. Método: Estudio descriptivo, transversal y cuantitativo de los casos confirmados de Sífilis Congénita en la microrregión registrados en el Sistema de Información de Agravios y Notificación. Resultados: En el período estudiado se confirmaron 39 casos, donde el 30,8% de las madres tiene entre 20 a 24 años, el 59% son pardas, el 46,2% tienen enseñanza fundamental incompleta, el 33,3% amas de casa, el 74,4% en el momento del parto / curetaje, el 41% recibió tratamiento inadecuado y el 38,5% de los socios no fueron tratados. Con respecto a los recién nacidos, el 69,2% fue diagnosticado con 0 días de vida, 74,4% con Sífilis Congénita reciente y 46,2% asintomáticos. Conclusión: Los datos revelan un serio problema de salud pública en la microrregión analizada apuntando también fallas en el sistema de notificación, observadas en el elevado índice de ignorados en las variables estudiadas

Objective: To analyze the epidemiological profile of Congenital Syphilis in 18 municipalities in the state of Bahia between 2007 and 2017. Method: A descriptive, cross-sectional and quantitative study of the confirmed cases of Congenital Syphilis in the micro-region registered in the Aggravation and Notification Information System. Results: In the study period, 39 cases were confirmed, with 30.8% of the mothers being between 20 and 24 years of age, 59% were brown, 46.2% had incomplete primary education, 33.3% were housewives, 74.4% 94.9% underwent prenatal care, 53.8% were diagnosed at the time of delivery / curettage, 41% received inadequate treatment and 38.5% of the partners were not treated. With regard to newborns, 69.2% were diagnosed with 0 day of life, 74.4% with recent Congenital Syphilis and 46.2% asymptomatic. Conclusion: The data reveal a serious public health problem in the micro-region analyzed, also pointing out failures in the notification system, observed in the high ignored index in the studied variables

Objetivo: Analisar o perfil epidemiológico de Sífilis Congênita em 18 municípios no interior do estado da Bahia entre 2007 e 2017. Método: Estudo descritivo, transversal e quantitativo dos casos confirmados de Sífilis Congênita na microrregião registrados no Sistema de Informação de Agravos e Notificação. Resultados: No período estudado foram confirmados 39 casos, onde 30,8% das mães tem entre 20 a 24 anos, 59% são pardas, 46,2% possuem ensino fundamental incompleto, 33,3% donas de casa, 74,4% residentes na zona urbana, 94,9% realizou o pré-natal, 53,8% foram diagnosticadas no momento do parto/curetagem, 41% receberam tratamento inadequado e 38,5% dos parceiros não foram tratados. Com relação aos recém-nascidos, 69,2% foram diagnosticados com 0 dia de vida, 74,4% com Sífilis Congênita recente e 46,2% assintomáticos. Conclusão: Os dados revelam um sério problema de saúde pública na microrregião analisada apontando também falhas no sistema de notificação, observadas no elevado índice de ignorados nas variáveis estudadas

Characteristics of Persons With Repeat Syphilis-Idaho, 2011 to 2015.

During 2011 through 2015 in Idaho, 14 (7%) of 193 persons with early syphilis had repeat syphilis. Persons with repeat infections were more likely to have had secondary or early latent syphilis (P = 0.037) and be infected with human immunodeficiency virus (P < 0.001) compared with those having 1 infection.

Reactor Grids for Prioritizing Syphilis Investigations: Are Primary Syphilis Cases Being Missed?

BACKGROUND: Health departments prioritize investigations of reported reactive serologic tests based on age, gender, and titer using reactor grids. We wondered how reactor grids are used in different programs, and if administratively closing investigations of low-titer tests could lead to missed primary syphilis cases. METHODS: We obtained a convenience sample of reactor grids from 13 health departments. Interviews with staff from several jurisdictions described the role of grids in surveillance and intervention. From 5 jurisdictions, trends in reactive nontreponemal tests and syphilis cases over time (2006-2015) were assessed by gender, age, and titer. In addition, nationally-reported primary syphilis cases (2013-2015) were analyzed to determine what proportion had low titers (≤1:4) that might be administratively closed by grids without further investigation. RESULTS: Grids and follow-up approaches varied widely. Health departments in the study received a total of 48,573 to 496,503 reactive serologies over a 10-year period (3044-57,242 per year). In 2006 to 2015, the number of reactive serologies increased 37% to 169%. Increases were largely driven by tests for men although the ratios of tests per reported case remained stable over time. Almost one quarter of reported primary syphilis had low titers that would be excluded by most grids. The number of potentially missed primary syphilis cases varied by gender and age with 41- to 54-year-old men accounting for most. CONCLUSIONS: Reactor grids that close tests with low titers or from older individuals may miss some primary syphilis cases. Automatic, computerized record searches of all reactive serologic tests could help improve prioritization.

Reported Cases of Neurosyphilis Among Early Syphilis Cases-United States, 2009 to 2015.

The surveillance of neurosyphilis, an uncommon but severe consequence of syphilis, is complex; surveillance classification of neurosyphilis requires a lumbar puncture and cerebrospinal fluid analysis. We examined the prevalence of reported neurosyphilis among primary, secondary, and early latent syphilis cases reported in the United States from 2009 to 2015. Overall, the prevalence of reported neurosyphilis from 2009 to 2015 was low (0.84%); however, this is likely an underestimate of the true burden in the United States.

Neurosífilis en el siglo XXI: estudio descriptivo en un hospital terciario de Madrid / Neurosyphilis in the 21st century: a descriptive study in a tertiary hospital in Madrid

Introducción. La neurosífilis puede ocurrir en cualquier momento tras la infección por Treponema pallidum y su incidencia está aumentando en los últimos años. El patrón epidemiológico y clínico ha experimentado un cambio sustancial en la era postantibiótica. Objetivo. Describir y analizar la población de pacientes con diagnóstico de neurosífilis de un hospital terciario de Madrid desde enero de 2008 a mayo 2015. Pacientes y métodos. Se analizaron retrospectivamente datos demográficos, clínicos, pruebas complementarias -serología, líquido cefalorraquídeo (LCR), neuroimagen- y evolución de 28 pacientes diagnosticados entre 2008 y 2015. Resultados. La mayoría fueron varones (89,3%), españoles (60,7%), con una edad media de 53 ± 16,4 años. Lo más frecuente fueron las formas asintomáticas (39,3%), seguidas de sífilis ocular (21%), formas no clásicas (14,3%), deterioro cognitivo y alteraciones neuropsiquiátricas (11%). El 50% presentaba infección concomitante por virus de la inmunodeficiencia humana, la mayoría asintomáticos, con una correlación significativa entre linfocitos T CD4+ y neurosífilis asintomática. Únicamente el 50% presentó VDRL+ en el LCR, basándose el diagnóstico en la clínica, la serología y las alteraciones en el LCR (citobioquímicas o serológicas). La neuroimagen fue inespecífica en la mayoría de los casos. Las formas tempranas y las formas oculares se asociaron a una mejor evolución clínica. Conclusiones. Respecto a la era preantibiótica, se observa un descenso muy importante en las formas tardías, así como la aparición de formas no clásicas que pueden simular otras entidades, como encefalitis víricas. El diagnóstico es complejo y se basa en la clínica, la serología y el estudio del LCR, a menudo con una interpretación compleja, por lo que la sospecha clínica es fundamental en el diagnóstico (AU)

Introduction. Neurosyphilis can occur at any time following infection by Treponema pallidum and its incidence has increased over recent years. The epidemiological and clinical pattern has undergone a substantial change in the post-antibiotic era. AIMS. To describe and analyse the population of patients diagnosed with neurosyphilis at a tertiary hospital in Madrid from January to May 2015. Patients and methods. A retrospective analysis of the following data was performed: demographic, clinical, complementary tests -serology, cerebrospinal fluid (CSF), neuroimaging- and progression of 28 patients diagnosed between 2008 and 2015. Results. Most of the patients were males (89.3%), Spanish (60.7%), with a mean age of 53 ± 16.4 years. The most frequent forms were asymptomatic (39.3%), followed by ocular syphilis (21%), non-classical forms (14.3%), cognitive deterioration and neuropsychiatric alterations (11%). Fifty per cent presented a concomitant infection by human immunodeficiency virus, most of them asymptomatic, with a significant correlation between CD4+ T-cells and asymptomatic neurosyphilis. Only 50% presented VDRL+ in CSF, the diagnosis being based on the clinical features, serology and alterations in CSF (cytobiochemical or serological). Neuroimages were unspecific in most cases. The early and ocular forms were associated to a better clinical course. Conclusions. With respect to the pre-antibiotic era, an important decrease can be observed in the late-onset forms, as well as the appearance of non-classical forms that can mimic other conditions such as viral encephalitis. Diagnosis is complex and based on the clinical features, the serology and study of CSF, often with a complex interpretation, and thus clinical suspicion plays a fundamental role in the diagnosis (AU)

Molecular Subtyping and Surveillance of Resistance Genes In Treponema pallidum DNA From Patients With Secondary and Latent Syphilis in Hunan, China.

BACKGROUND: Over the past decade, the incidence of syphilis and widespread macrolide resistance in its etiological agent, Treponema pallidum subsp. pallidum, have become a major health concern across countries, including China. Regional trends in subtypes and antibiotic resistance can be monitored effectively by molecular surveillance programs. In this study, whole blood samples were used to assess circulating T. pallidum strains collected from various regions of Hunan, China, between 2013 and 2015. METHODS: Traditional polymerase chain reaction, targeting polA, tpp47, bmp, and tp0319 genes, was used as preliminary screening assay. About 455 polymerase chain reaction-positive specimens were obtained from 2253 whole blood samples of patients with secondary or latent syphilis. Molecular subtyping was performed using a Centers for Disease Control and Prevention-based typing method combined with an analysis of the variable region of tp0548 gene. Resistance to macrolides was analyzed by examining point mutations in 23S rRNA, and the presence of the G1058C point mutation within 16S rRNA associated with decreased susceptibility to doxycycline was assessed. RESULTS: Circulating T. pallidum strains were resolved into 32 subtypes, among which subtype 14d/f was predominant. A2059G mutation in 23S rRNA, and the G1058C mutation in 16S rRNA was absent, but the prevalence of A2058G mutation in 23S rRNA was 97.5%. CONCLUSIONS: We found that it is possible to use whole blood to evaluate molecular subtypes and monitor antibiotic resistance in circulating T. pallidum strains, especially when chancres are absent. High frequency of macrolide-resistant T. pallidum indicates that macrolide antibiotics, such as azithromycin, should be avoided as a treatment option for syphilis in Hunan, China.

Prevalence Estimates of Complicated Syphilis.

We reviewed 68 cases of possible neurosyphilis among 573 syphilis cases in King County, WA, from 3rd January 2012 to 30th September 2013; 7.9% (95% confidence interval, 5.8%-10.5%) had vision or hearing changes, and 3.5% (95% confidence interval, 2.2%-5.4%) had both symptoms and objective confirmation of complicated syphilis with either abnormal cerebrospinal fluid or an abnormal ophthalmologic examination.

Syphilis in the United States.

Syphilis gained notoriety in the 1500s, when it became widespread throughout Europe. While the origins of syphilis are not certain, recent data have shown that it may have originated in the Americas from a close relative that causes Yaws (Treponema pallidum pertenue).(1) For the past 500years, the disease has shown its various faces all over the world. The 19th century saw an entire medical subspecialty-syphilology (sometimes known as syphilography)-devoted to the study of the great disease, then known as "the great imitator." Syphilis has an entire textbook of presentations and can mimic many other infections and immune-mediated processes. At the beginning of the 20th century, the many faces of the disease led to Sir William Osler's well-known aphorism, "The physician who knows syphilis knows medicine."(2) When penicillin was discovered, and used to treat syphilis in 1943, some thought that syphilis would go by the wayside, but syphilis continued what it has been doing for so many years . . . inconspicuously infecting humans. The United States has seen the incidence of syphilis increase numerous times throughout the past 70years. Every decrease in the incidence of syphilis is followed shortly by an increase. A marked shift in the epidemiology occurred from 1990 to 2000. In the 1990s, syphilis primarily occurred in heterosexual minority groups. In the new millennium, a majority of cases of syphilis are now transmitted among men who have sex with men (MSM).(3) This contribution discusses the incidence of syphilis in the United States and the reasons these trends continue.

Prevalence of latent tuberculosis, syphilis, hepatitis B and C among asylum seekers in Malta.

BACKGROUND: In the last few years, Malta has witnessed increasing immigration flows from the Libyan coasts. Public health policies are focused on screening migrants for tuberculosis, whereas no systematic actions against STIs are implemented. The aim of this study is to define the epidemiological profile of asylum seekers in Malta as regards syphilis, hepatitis B, C and latent tuberculosis, thus supporting screening policies. METHODS: Five hundred migrants living in open centres were screened between December 2010 and June 2011. RESULTS: 83.2% of people was from Somalia, 81.2% males, average age 26.5 years. The tuberculin skin test (TST) was positive in 225 migrants (45%). Latent syphilis was diagnosed in 11 migrants, hepatitis C in 3 and 31 migrants were HBsAg positive. CONCLUSION: Systematic screening for asymptomatic migrants in Malta is not recommended for hepatitis C and syphilis, given the low prevalence observed. On the contrary, it should be considered for hepatitis B. TST could be indicated as the first step of a two step screening for migrants from countries with high TB incidence. Efficacy and cost-effectiveness could be achieved by further targeting screening to specific subgroups at higher risk of reactivation, such as people living with HIV and subjects affected by chronic diseases.

Latent syphilis among inpatients in an urban area of China.

We aimed at investigating the epidemiological features of latent syphilis among inpatients in an urban area of China. During the period of Jan 1999 to Dec 2007, 146 inpatients were positive for treponema pallidum particle agglutination (TPPA) assay from 22,454 inpatients who were admitted to the China Meitan General Hospital. The number of latent syphilis increased steadily during this period of time. From the 146 TPPA positive inpatients, 137 inpatients were diagnosed as latent syphilis. The number of male patients with latent syphilis was slightly more than the female, but there was no statistical significance (P>0.01). The number of male patients over 60 years old was 42 (30.66%), which was higher than other age groups (p<0.05). The number of female patients at the age range of 20-29 years was 20 (14.60%), which was higher than other age groups (p<0.05). Our results demonstrated that routine syphilis screening among inpatients proves to be one of the most effective precautionary measures to identify latent syphilis and thus to prevent transmission in urban areas in China.

¿Somos capaces de erradicar la sífilis congénita? / Are we able to eliminate congenital syphilis?

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[Syphilis and pregnancy: study of 94 cases]. / Sífilis y embarazo: estudio de 94 casos.

BACKGROUND AND OBJECTIVE: To study the epidemiology, diagnosis, treatment strategies and perinatal outcomes of gestational syphilis. PATIENTS AND METHOD: We performed a retrospective study of 94 pregnant women with syphilis whose gestation and delivery were monitored in a Department of Obstetrics from 2002 to 2010 among a total of 85,806 births of women without syphilis in the same period. RESULTS: The prevalence of gestational syphilis was 0.11%. Most of the women were foreign and the most prevalent type was late latent syphilis. Only 57 patients underwent right treatment despite adequate prescription. Maternal complications were confirmed in 31 pregnant women and 16 cases had fetal complications. We diagnosed 4 cases of neonatal syphilis, 3 of them with syphilitic meningitis, whose mothers had not completed the treatment correctly. CONCLUSIONS: The implementation of a mandatory syphilis serology in the pregnancy has enabled us to diagnose many cases of late latent syphilis. The successful completion of treatment must be ensured to prevent vertical transmission.

[Trend of syphilis among patients at the Infectious Diseases Clinic of Perugia, Italy: a six-year observational retrospective study]. / Trend dell'infezione luetica tra i pazienti della Clinica delle Malattie Infettive di Perugia in un periodo di 6 anni.

In order to describe the trend of syphilis at the Infectious Diseases Clinic of Perugia University, Italy, over a six-year period (2005-2010), 138 patients were identified and monitored. Syphilis diagnosis was as follows: latent 60%, secondary 21%, neurosyphilis 10%, primary 9%. The study population comprised 83% males, 59% Italians and 45% men who have sex with men (MSMs). Heterosexual females represented 28.5% cases among immigrants and 8.5% cases among Italians, while men with unknown sexual contacts were 28% and 14% respectively (p=0.0059). HIV co-infection was detected in 70% of patients, with a predominance of males (94%) and Italians (62%). Among HIV-positive patients, 63% were pre-existing HIV-infected: of these, 26% had primary or secondary syphilis. During the study period, the number of regional syphilis notifications at the Italian Health Department was lower with respect to the observed cases at the Infectious Diseases Clinic of Perugia (69 versus 138). Globally, the trend of syphilis infection remained stable over the six-year period. However, efforts to improve prevention and screening programs are required for persons at risk of both syphilis and HIV infection, as well as measures to strengthen syphilis notification procedures.

[Syphilis]. / Syphilis.

Syphilis is back since 2000. Early syphilis comprises primary syphilis, secondary syphilis and early latent syphilis (less than 1 year duration). During early phases of syphilis, patients are more contagious and neurologic complications are rare. Early neurosyphilis are mostly represented by uveitis or cranial nerves lesions. Treatment of non-neurologic syphilis are based on intramusculary injection of benzathine-penicilline G: one injection in case of early syphilis, three injections in case of late syphilis. The follow-up after treatment is based on clinical evolution and the titer of VDRL. Intravenously infusion of penicillin G is the only treatment recommended for neurosyphilis.

Characteristics of patients with primary and late latent syphilis patients who were initially non-reactive to the rapid plasma reagin test.

We aimed at determining the characteristics of patients with primary and late latent syphilis who were non-reactive on initial screening by rapid plasma reagin (RPR) but reactive by treponemal tests. We collected the RPR test results of all primary and late latent syphilis patients in our hospital from December 2000 to March 2012. The characteristics of syphilis patients who were non-reactive by RPR testing were compared to those of reactive patients. Multiple logistic regression was used to identify factors associated with non-reactive RPR results. Among primary syphilis patients, 37 (16.5%) were non-reactive on initial RPR and were compared with the 187 reactive cases. Age >35 years was an independent factor associated with a non-reactive result in primary cases (odds ratio [OR], 95% confidence intervals [CI] = 3.55 [1.39-9.07]). Of the late latent patients, 61 (8.8%) were non-reactive by RPR and 636 were reactive. Age >34 years was also an independent factor associated with a non-reactive result in late latent cases (OR [95% CI] = 4.30 [2.28-8.12]). This study suggests that RPR testing alone is insufficient to diagnose primary and late latent infections, especially in middle-aged and elderly individuals. Syphilis detection was lower for patients with primary syphilis than for those with late latent syphilis based on the results of the RPR.