Primary syphilis cases in Guangdong Province 1995-2008: opportunities for linking syphilis control and regional development

The evaluation of preventive and control measures on congenital syphilis in Guangdong Province, China: a time series modeling study

Purpose

To evaluate the effectiveness of preventive and control measures for congenital syphilis (CS) implemented since 2012 in Guangdong Province, China, and assess the epidemic trend in the near future.

Methods

The interrupted time series analysis was conducted to compare changes in slope and level of CS notification rate from 2005 to 2020 in Guangdong Province and its three regions with different economic developmental levels. The ARIMA model was established to predict the new CS case number of Guangdong Province in 2021.

Results

A total of 12,687 CS cases were reported from 2005 to 2020. The CS notification rate of the province had been increasing until 2012 (128.55 cases per 100,000 live births) and then been decreasing constantly, hitting the lowest point in 2020 (5.76 cases per 100,000 live births). The severe epidemic cluster shifted from the developed region to underdeveloped ones over time. The effectiveness of the measures was proved by the significant change in the slope of the notification rate which was found in both of the provinces (− 18.18, 95% CI − 25.63 to − 10.75) and two less-developed regions (− 10.49, 95% CI − 13.13 to − 7.86 and − 32.89, 95% CI − 41.67 to − 24.10, respectively). In the developed region where the notification rate had already been decreasing in the pre-implementation period, implementing these measures also aided in hastening the rate of descent. The CS case number in 2021 was predicted to be 48, indicating a low-level epidemic.

Conclusions

The preventive and control measures have assisted Guangdong Province to control CS effectively, of which the supportive ones ensured a successful implementation. For resource-limited countries where CS is still endemic, especially guaranteeing the support in financial subsidy, professional training, supervision and so on might trigger the effectiveness of other measures and eventually make significant and sustainable progress.

Supplementary Information

The online version contains supplementary material available at 10.1007/s15010-022-01791-1.

Spatial-temporal analysis of HIV/AIDS and syphilis in mainland China from 2007 to 2017

Human immune deficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) and syphilis are the most common sexually transmitted diseases (STDs) worldwide, as well as in China. The objective of this study is to describe the trend of spatial and temporal variation of HIV/AIDS and syphilis in mainland China from 2007 to 2017. Stratified analysis was conducted according to age and the GDP per capita. Estimated Annual Percentage Change (EAPC) was calculated and spatial autocorrelation analysis was used to evaluate the epidemiology and identify clusters. The morbidity of new HIV infection increased from 2.5034/100 000 in 2007 to 6.9247/100 000 in 2017, with an EAPC of 9.84 (95% confidence interval [CI]: 9.07-10.60). From 2007 to 2017, the morbidity of syphilis presented a significant upward trend from 15.8834/100 000 to 34.4867/100 000 (EAPC = 6.48, 95% CI: 4.23-8.73). The number of new HIV infections (205 084) and syphilis (921 279) were highest in the 20-30 years old group, where the incidence decreased with age over 20 years. In general, HIV and syphilis infection had the same incidence trend according to age and time stratification. The morbidity of new HIV infection was mainly reported from Xinjiang and southwestern China. As for syphilis, the highest was found in Zhejiang in Xinjiang and southeast coastal areas. Both HIV and syphilis infection showed a nonrandom positive correlation by Moran's I value. The High-High cluster areas of HIV infection were concentrated in southwestern and eastern China due to syphilis. A highly significant positive correlation was found between gross domestic product per capita and syphilis infection (p < 0.05) but was not associated with HIV infection. The incidence of AIDS/HIV and syphilis is increasing year by year, and a higher prevalence is found in younger individuals. More attention should be paid to HIV infection in the southwest, syphilis in southeast coastal areas, and both the two diseases in Xinjiang.

New Syphilis Cases in Older Adults, 2004-2019: An Analysis of Surveillance Data From South China

Background: Sexual health among older adults is a major public health concern globally. The syphilis burden is increasing in older adults in China. This study aimed to describe factors associated with syphilis infection and diagnosis among older adults in China during a 16 year period. Methods: Using 16 years of data (2004-2019) from the syphilis case report system of Guangdong, China, we compared data from older adults (aged ≥50 years) with those from younger people (aged 15-49 years). We compared the two age group with the Chi-square test for difference, and Joinpoint regression models to assess the temporal trends. Results: During the study period, 242,115 new syphilis diagnoses were reported in older adults. The mean notification rate of new diagnoses was 64.1 per 100,000 population across the entire 16-year period, which significantly increased over time (average annual percent change [AAPC] 16.2%, 95% CI 13.7-18.7). Syphilis diagnoses increased significantly over time among less developed cities and older women. In 2019, compared with younger adults, newly diagnosed older adults were more likely to be male, native to reporting city, had unknown transmission routes, and were diagnosed late. Conclusion: Our findings call for an urgent need to deliver more targeted prevention interventions for older adults, such as strengthen awareness among health care providers, and integration of syphilis services and primary health care for older adults.

Predictors of Seronegative Conversion After Centralized Management of Syphilis Patients in Shenzhen, China

Objective: The aim of this study was to explore the seronegative conversion status of syphilis patients after centralized management and to analyze potential determinants.

Materials and Methods: A retrospective population-based cohort study was conducted, and data for individuals who had been diagnosed with syphilis between 2011 and 2019 were retrieved from the Shenzhen Nanshan Center for Chronic Disease Control. Seroconversion statuses were summarized as percentages. Univariable and multiple Cox proportional hazard regression models were used to analyze the factors associated with seronegative conversion among syphilis patients.

Results: During the study period, 1,545 patients with syphilis participated in the syphilis convergence case management program on a voluntary basis, of whom 290 were excluded due to missing follow-up data. A total of 27.6% (346/1255) of patients with syphilis showed seronegative conversion. Multivariable analysis revealed that the following significantly determined syphilis seroconversion from positive to negative: younger age (15–19 years vs. ≥30 years: HR = 2.18), male gender (HR = 1.45), lower baseline toluidine red unheated serum test (TRUST) titer of ≤ 1:8 (HR = 2.23), and different disease stages, including latent syphilis (HR = 1.98), primary syphilis (HR = 7.67), and secondary syphilis (HR = 4.83).

Conclusions: Few patients with syphilis tested negative after treatment at the end of the study. Seronegative conversion in the patients was associated with age, sex, baseline TRUST titer, and syphilis stage.

Concurrent tuberculous transverse myelitis and asymptomatic neurosyphilis: A case report

BACKGROUND

Tuberculous myelitis is a rare manifestation of tuberculosis (TB) that is usually caused by hematogenous spread of Mycobacterium tuberculosis (MTB). Neurosyphilis is a neurological disease that occurs when Treponema pallidum invades the brain or the spinal cord. Individually, these two diseases involving the spinal cord are rare and cases of concurrent tuberculous transverse myelitis and asymptomatic neurosyphilis have seldom been reported.

CASE SUMMARY

A 56-year-old man presented with numbness and pain of both lower limbs for 2 wk and dysuria for 1 wk. Syphilis serology and cerebrospinal fluid (CSF) analysis supported the diagnosis of neurosyphilis and the patient was treated with intravenous ceftriaxone at first, but symptoms still progressed. Then, magnetic resonance images revealed multiple lesions along the cervicothoracic junction, and chest computed tomography showed a typical TB lesion. MTB DNA was detected in the CSF sample by metagenomic next-generation sequencing. Eventually the patient was diagnosed with tuberculous myelitis combined with asymptomatic neurosyphilis. Subsequently, quadruple anti-TB drug standardized therapy was empirically used and his neurological symptoms improved gradually.

CONCLUSION

Patients can have coinfection with tuberculous transverse myelitis and asymptomatic neurosyphilis. Patients with neurosyphilis should be examined for other pathogens.

The effect of public health awareness and behaviors on the transmission dynamics of syphilis in Northwest China, 2006-2018, based on a multiple-stages mathematical model

Syphilis, a sexually transmitted infectious disease caused by the bacterium treponema pallidum, has re-emerged as a global public health issue with an estimated 12 million people infected each year. Understanding the impacts of health awareness and behaviors on transmission dynamics of syphilis can help to establish optimal control strategy in different regions. In this paper, we develop a multiple-stage SIRS epidemic model taking into account the public health awareness and behaviors of syphilis. First, the basic reproduction number R0 is obtained, which determines the global dynamics behaviors of the model. We derive the necessary conditions for implementing optimal control and the corresponding optimal solution for mitigation syphilis by using Pontryagin's Maximum Principle. Based on the data of syphilis in Ningxia from 2006 to 2018, the parameterizations and model calibration are carried out. The fitting results are in good agreement with the data. Moreover, sensitivity analysis shows that the public awareness induced protective behaviors C_e, compliance of condom-induced preventability ε and treatment for the primary syphilis m₁ play an important role in mitigating the risk of syphilis outbreaks. These results can help us gain insights into the epidemiology of syphilis and provide guidance for the public health authorities to implement health education programs.

Spatiotemporal distribution and sociodemographic and socioeconomic factors associated with primary and secondary syphilis in Guangdong, China, 2005-2017

Background

Previous studies exploring the factors associated with the incidence of syphilis have mostly focused on individual-level factors. However, recent evidence has indicated that social-level factors, such as sociodemographic and socioeconomic factors, also affect the incidence of syphilis. Studies on the sociodemographic and socioeconomic factors associated with syphilis incidence are scarce, and they have rarely controlled for spatial effects, even though syphilis shows spatial autocorrelation.

Methodology/Principal findings

Syphilis data from 21 cities in Guangdong province between 2005 and 2017 were provided by the National Notifiable Infectious Disease Reporting Information System. The incidence time series, incidence map, and space-time scanning data were used to visualize the spatiotemporal distribution. The spatial panel data model was then applied to explore the relationship between sociodemographic factors (population density, net migration rate, male:female ratio, and the number of health institutions per 1,000 residents), socioeconomic factors (gross domestic product per capita, the proportion of secondary/tertiary industry), and the incidence of primary and secondary syphilis after controlling for spatial effects. The incidence of syphilis increased slowly from 2005 (11.91 per 100,000) to 2011 (13.42 per 100,000) and then began to decrease, reaching 6.55 per 100,000 in 2017. High-risk clusters of syphilis tended to shift from developed areas to underdeveloped areas. An inverted U-shaped relationship was found between syphilis incidence and gross domestic product per capita. Moreover, syphilis incidence was significantly associated with population density (β = 2.844, P = 0.006), the number of health institutions per 1,000 residents (β = -0.095, P = 0.007), and the net migration rate (β = -0.219, P = 0.002).

Conclusions/Significance

Our findings suggest that the incidence of primary and secondary syphilis first increase before decreasing as economic development increases further. These results emphasize the necessity to prevent syphilis in regions at the early stages of economic growth.

Syphilis is a sexually transmitted infection that continues to cause morbidity and mortality worldwide. The primary and secondary stages of syphilis are the most transmissive stages in the entire process of the disease. We analyzed primary and secondary (P&S) syphilis data from 2005 to 2017 in Guangzhou, China, provided by the National Notifiable Infectious Disease Reporting Information System. The results showed that the annual incidence rates of P&S syphilis slightly increased from 2005 to 2011 and then began to decrease in 2017. Cases of P&S syphilis were spatially clustered. The high-risk syphilis clusters tended to shift from developed areas to underdeveloped areas. There may be an inverted U-shaped relationship between the level of economic development and the incidence of P&S syphilis, suggesting that the incidence of P&S syphilis first increased before decreasing as the level of economic development increased further. These results emphasize the necessity of preventing syphilis at locations in the early stage of economic growth. Investments in syphilis prevention education for people in regions at early development stages may mitigate the increasing cost of syphilis to future healthcare systems.

Spatiotemporal analysis of 11 years of Chlamydia trachomatis data from southern China

BACKGROUND

Urogenital Chlamydia trachomatis is the most prevalent bacterial sexually transmitted infection (STI) globally. Reviews suggest high and persistently endemic STI epidemics in low and middle income countries. However population-based prevalence estimates in these settings are less common, underscoring the need for analyses of available data to characterize patterns of disease burden. We identified spatio-temporal clusters and key behavioral, social, or environmental factors contribution to transmission in order to inform the prioritization and targeting of evidence based interventions.

METHODS

Using 11 years of data (2006-2016) from the chlamydia case report system of Guangdong, China, we identified county level spatio-temporal hot and cold spots using the Getis-Ord Gi* statistic and discrete Poisson models in SaTScan 9.6. We also estimated associations between observed distribution patterns and area-level demographic, social, and economic factors using quasi-Poisson regression models that controlled for annual counts of certified laboratories to account for fluctuations in location-specific detection capacity.

FINDINGS

Cluster analysis indicates an expanding chlamydia epidemic in Guangdong, with cases clustered in regions of greatest economic activity. Greater male-to-female sex ratio (RR, 3.63; 95% CI, 1.41-9.45) and greater urbanicity (RR, 2.44; 95% CI, 1.98-2.99) were predictive of higher chlamydia case occurrence.

INTERPRETATION

We found that chlamydia case occurrence in Guangdong province has been accelerating over the past 11 years and that its expansion is tied to indicators of social and economic development. These estimates not only identify high prevalence regions to target but also areas where data gaps potentially remain. The salience of sex ratios and urbanicity may best be understood through the lens of China's modern history of labor migration which has reshaped the gender dynamics and health access landscape of urban China. Future chlamydia control efforts will require a population-based approach focused on reengaging sexually active adults of diverse economic and migratory backgrounds.

FUNDING

This was an unfunded study using routinely collected public health data.

Predictors of serological cure after penicillin therapy in HIV-negative patients with early syphilis in Shenzhen, China

BACKGROUND

Syphilis is a common infectious disease worldwide. Serological monitoring is important for syphilis management. We currently know little about the characteristics of this seronegative response. The aim of this study was to explore the factors associated with serological cure after treatment of early syphilis.

METHODS

A retrospective cohort study was conducted and the data of patients with early syphilis in a clinic in Shenzhen from 2011 to 2019 were retrieved. Univariable and multiple Cox proportional hazard regression models were utilized to identify factors associated with a serological cure state among syphilis patients with early syphilis two years after treatment.

RESULTS

A total of 346 (85.9%) syphilis patients achieved serological cure. The multivariate analysis results revealed that having a baseline TRUST titer >1:8 was associated with an increased probability of serological cure, compared with having a baseline TRUST titer ≤1:8 (HR = 1.43, 95% CI = 1.10-1.85, P<0.01); primary syphilis was positively associated with serological cure, compared with participants with latent early syphilis (HR = 1.72, 95% CI = 1.27-2.33, P<0.001).

CONCLUSIONS

Two years after treatment, a higher percentage of early syphilis patients achieved serological cure. The study indicated that the syphilis stage and baseline serum titer were crucial factors associated with serological cure.

Modelling the impact of a sex work crackdown on syphilis transmission among female sex workers and their clients in South China

OBJECTIVE

To estimate the potential effects of an intense sex work crackdown on syphilis transmission in Guangdong Province, China.

METHODS

We developed a deterministic compartmental model of syphilis transmission among female sex workers (FSW) and their male clients in Guangdong Province, China. We based model assumptions on census data and scientific literature, and we fitted the model to sentinel surveillance estimates of syphilis prevalence (positive results in both treponemal and non-treponemal tests) among FSW between 2009 and 2013. We estimated the impact of an intense sex work crackdown in 2014 by comparing the number of new syphilis infections between 2014 and 2020 in crackdown versus basecase (no crackdown) scenarios. In modelling scenarios, we examined main crackdown mechanisms of impact, including changed number of FSW engaging in sex work, reduction of weekly transactions, condom usage rate and syphilis diagnosis rate.

RESULTS

In the basecase, predicted syphilis prevalence in FSW decreased from 2% in 2014 to 0.4% in 2020. In crackdown scenarios, syphilis incidence was predicted to transiently decrease and then to rebound relative to basecase levels a few years later. Shorter crackdowns led to higher, faster rebounds.

CONCLUSIONS

Short-term intense crackdowns may exacerbate syphilis transmission among FSW and further marginalise an already vulnerable group. This study provides a quantitative, infection-related basis for changing sex work policies to reduce harms.

Mathematical Assessment of the Role of Early Latent Infections and Targeted Control Strategies on Syphilis Transmission Dynamics

A new multi-stage deterministic model for the transmission dynamics of syphilis, which incorporates disease transmission by individuals in the early latent stage of syphilis infection and the reversions of early latent syphilis to the primary and secondary stages, is formulated and rigorously analysed. The model is used to assess the population-level impact of preventive (condom use) and therapeutic measures (treatment using antibiotics) against the spread of the disease in a community. It is shown that the disease-free equilibrium of the model is globally-asymptotically stable whenever the associated control reproduction number (denoted by [Formula: see text]) is less than unity. A special case of the model is shown to have a unique and globally-asymptotically stable endemic equilibrium whenever the associated reproduction number (denoted by [Formula: see text]) exceeds unity. Uncertainty and sensitivity analysis of the model, using parameter values and ranges relevant to syphilis transmission dynamics in Nigeria, show that the top three parameters that drive the syphilis infection (with respect to [Formula: see text]) are the disease transmission rate ([Formula: see text]), compliance in condom use (c) and efficacy of condom ([Formula: see text]). Numerical simulations of the model show that the targeted treatment of secondary syphilis cases is more effective than the targeted treatment of individuals in the primary or early latent stage of syphilis infection.

Distribution of reported syphilis cases in South China: spatiotemporal analysis

There was a varied spatial distribution of reported syphilis cases across cities in South China. This study aims to identify and describe spatiotemporal clusters of primary and secondary syphilis (P/S) cases in this region. Reported syphilis cases in Guangdong Province, China, from January 2014 to June 2015 were collected from the national centralized reporting system. Spatiotemporal clusters of P/S were identified and cross-validated by calculating local Moran's I, performing hotspot analysis (Getis-Ord Gi*), and constructing a discrete Poisson model in SaTScan. Reported cases within and outside the clusters were compared by bivariable and multivariable logistic regression. Out of 17,691 reported P/S cases, 11% were in the identified spatiotemporal clusters. The monthly P/S notification rate (per 100,000 persons) ranged between 0.6 and 1. The identified clusters were located in 14, out of 126, counties in eight, out of 21, cities. Cases of older age, living in rural area and taking self-initiated syphilis test were more likely to be in the clusters. Some areas bore a greater burden of P/S in Guangdong Province. Routine spatiotemporal analysis of P/S cases may be useful for enhancing syphilis control programs by strategic location-based service planning.

The association between human perceived heat and early-stage syphilis and its variance: Results from a case-report system

BACKGROUND

The relationship between temperature and syphilis is poorly understood despite clues and suggestions from previous studies. We examined the association between human perceived temperature (humidex) and the relative risk of early-stage syphilis in the most affected area of China, as well as its variance across social-economic status and age groups.

METHODS

Information regarding early-stage (primary and secondary) syphilis cases reported to the China Case Report System between 2005-2013 from Guangdong province was analyzed in this study. Weather data were obtained from the National Meteorological Information Center. Distributed lag nonlinear models were applied to assess the relationship between humidex and the relative risk of early-stage syphilis. Results were further stratified by social-economic status and age groups.

RESULTS

The relative risks of early-stage syphilis mainly increased with increased humidex, and were elevated when the humidex was around 30 or greater than 38. The humidex-RR association for the 15-40 age group was similar to the scenario pooled across the age groups, particularly in the Pearl-River Delta Region. The relative risk of syphilis in the elderly for the non-Pearl-River Delta Region did not show a clear change with humidex, whereas that in the Pearl-River Delta Region substantially increased, particularly when humidex was above 25.

CONCLUSIONS

Human perceived temperature was positively related to the relative risk of early-stage syphilis. People in the Pearl-River Delta Region tended to be more sensitive, with relative risk elevated at potential comfortable times or under excessively hot conditions. The vulnerability of the elderly in the Pearl-River Delta Region is concerning.

Stages of syphilis in South China - a multilevel analysis of early diagnosis

Background

Early diagnosis of syphilis and timely treatment can effectively reduce ongoing syphilis transmission and morbidity. We examined the factors associated with the early diagnosis of syphilis to inform syphilis screening strategic planning.

Methods

In an observational study, we analyzed reported syphilis cases in Guangdong Province, China (from 2014 to mid-2015) accessed from the national case-based surveillance system. We categorized primary and secondary syphilis cases as early diagnosis and categorized latent and tertiary syphilis as delayed diagnosis. Univariate analyses and multivariable logistic regressions were performed to identify the factors associated with early diagnosis. We also examined the factors associated with early diagnosis at the individual and city levels in multilevel logistic regression models with cases nested by city (n = 21), adjusted for age at diagnosis and gender.

Results

Among 83,944 diagnosed syphilis cases, 22% were early diagnoses. The city-level early diagnosis rate ranged from 7 to 46%, consistent with substantial geographic variation as shown in the multilevel model. Early diagnosis was associated with cases presenting to specialist clinics for screening, being male and attaining higher education level. Cases received syphilis testing in institutions and hospitals, and diagnosed in hospitals were less likely to be in early diagnosis. At the city-level, cases living in a city equipped with more hospitals per capita were less likely to be early diagnosis.

Conclusions

To enhance early diagnosis of syphilis, city-specific syphilis screening strategies with a mix of passive and client/provider-initiated testing might be a useful approach.

Multivariate time series analysis on the dynamic relationship between Class B notifiable diseases and gross domestic product (GDP) in China

The surveillance of infectious diseases is of great importance for disease control and prevention, and more attention should be paid to the Class B notifiable diseases in China. Meanwhile, according to the International Monetary Fund (IMF), the annual growth of Chinese gross domestic product (GDP) would decelerate below 7% after many years of soaring. Under such circumstances, this study aimed to answer what will happen to the incidence rates of infectious diseases in China if Chinese GDP growth remained below 7% in the next five years. Firstly, time plots and cross-correlation matrices were presented to illustrate the characteristics of data. Then, the multivariate time series (MTS) models were proposed to explore the dynamic relationship between incidence rates and GDP. Three kinds of MTS models, i.e., vector auto-regressive (VAR) model for original series, VAR model for differenced series and error-correction model (ECM), were considered in this study. The rank of error-correction term was taken as an indicator for model selection. Finally, our results suggested that four kinds of infectious diseases (epidemic hemorrhagic fever, pertussis, scarlet fever and syphilis) might need attention in China because their incidence rates have increased since the year 2010.

Poor awareness of syphilis prevention and treatment knowledge among six different populations in south China

BACKGROUND

China is facing an emerging epidemic of syphilis, and the cities in south China are most affected. Knowledge is a key factor in the prevention of syphilis infection, however, little is reported about how much people know about syphilis. This study was aimed at assessing peoples' awareness status in a city located in south China.

METHODS

Six populations were recruited for this study, including urban residents, factory workers, college students, pregnant women, female sex workers (FSWs), and men who have sex with men (MSM). A questionnaire designed by the National Center for Disease Control and Prevention was used to assess participants' awareness of syphilis knowledge. About 5% of participants were randomly selected to conduct a telephone survey for confirming the validity of fieldwork.

RESULTS

The study recruited 3470 participants, and 61.2% of participants were assigned to the awareness group. College students had the smallest percentage of awareness at 51.7% (371/718), followed by FSWs at 53.9% (200/371), factory workers at 56.0% (381/679), urban residents at 65.4% (435/665), pregnant women at 66.0% (451/683), and MSM at 81.1% (287/354). Multivariate logistic regression analysis showed that MSM and FSWs-but not factory workers and pregnant women-had more awareness of syphilis knowledge when comparing with urban residents; however, college students presented less awareness of syphilis knowledge than urban residents. Participants of younger age, of female gender, with lower education levels and without Shenzhen hukou possessed less awareness of syphilis knowledge than those of older age, of male gender, with higher education levels and with Shenzhen hukou respectively.

CONCLUSIONS

The percentages of awareness on syphilis knowledge found in this study are far from the benchmark set in the national 10-year plan. Tailored interventions for different subgroups to increase syphilis awareness are urgently warranted.

Syphilis in the economic center of South China: results from a real-time, web-based surveillance program

Background

Guangzhou is the economic center of South China, which is currently suffering an insidious re-emergence of syphilis. Syphilis epidemic in this area is a matter of serious concern, because of the special economic position of Guangzhou and its large migrant population. Therefore, a comprehensive analysis of surveillance data is needed to provide further information for developing targeted control programs.

Method

Case-based surveillance data obtained from a real-time, web-based system were analyzed. A hierarchical clustering method was applied to classify the 12 districts of Guangzhou into several epidemiological regions. The district-level annual incidence and clustering results were displayed on the same map to show the spatial patterns of syphilis in Guangzhou.

Results

A total of 60,178 syphilis cases were reported during the period from 2005 to 2013, among which primary/secondary syphilis accounted for 15,864 cases (26.36 %), latent syphilis for 41,078 cases (68.26 %) and congenital syphilis for 2,090 cases (3.47 %). Moreover, primary/secondary syphilis burden slightly decreased from 17.5-18.0 cases per 100,000 people in the first years to 10.6 cases per 100,000 in 2013, with latent syphilis largely increasing from 18.5 cases per 100,000 to 43.4 cases per 100,000. Districts of Guangzhou could be classified into 3 epidemiological regions according to the syphilis burden over the last 3 years of the study period.

Conclusions

The burden of primary/secondary syphilis appears to be decreasing in recent years, whereas that of latent syphilis is increasing. Given the epidemiological features and the annual changes found in this study, it is suggested that future control programs should be more population-specific and spatially targeted.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1072-z) contains supplementary material, which is available to authorized users.

Clinical Outcomes of In Vitro Fertilization among Chinese Infertile Couples Treated for Syphilis Infection

To compare the clinical outcomes of infertile patients with and without syphilis after in vitro fertilization and embryo transfer (IVF-ET), in this case-control study, 320 infertile couples were enrolled and divided into syphilis (n = 160) and control groups (n = 160). The primary IVF outcomes were the clinical pregnancy rate and the birth of a healthy baby. All syphilis patients received the standard anti-syphilis treatment before undergoing IVF/ICSI. Our results showed that the endometrial thickness of the syphilis group was greater than that of the control group following hCG injection (16.9±5.4 vs. 13.0±4.7 mm, P<0.001). The numbers of normally fertilized eggs and normally cleaved fertilized eggs and the implantation rate were 6.8±4.8, 6.3±4.7 and 24.2%, respectively, for the syphilis group and 8.3±4.6, 8.1±4.6 and 34.4%, respectively, for the control group, and these values were significantly different between the groups. The clinical pregnancy rate was lower in the syphilis group compared with that in the control group (43.8% vs. 55.6%, P = 0.03). Lower offspring birth weight was observed in the infected male group compared with those in the infected female (2.7±0.4 vs. 3.0±0.4 kg, P = 0.01) and infected couple groups (2.7±0.4 vs. 3.1±0.5 kg, P = 0.007). Therefore, syphilis infection reduces the clinical pregnancy rate after IVF/ICSI.

Organizational characteristics of HIV/syphilis testing services for men who have sex with men in South China: a social entrepreneurship analysis and implications for creating sustainable service models

Background

UNAIDS has called for greater HIV/syphilis testing worldwide just as local HIV/syphilis testing programs are cut or altered. New models are needed to make HIV/syphilis testing services sustainable while retaining their essential public health function. Social entrepreneurship, using business principles to promote a social cause, provides a framework to pilot programs that sustainably expand testing. Drawing on fieldwork in two South Chinese cities, we examined organizational and financial characteristics of current HIV/syphilis testing systems for men who have sex with men (MSM) in addition to new pilot programs focused on revenue-generation for sustainability.

Methods

We undertook a qualitative study to explore organizational and financial characteristics of HIV/syphilis testing for MSM. Data were collected from men who have sex with men and policy stakeholders in Guangzhou and Hong Kong. Framework analysis was used to identify themes and then code the data.

Results

Our qualitative research study included MSM and policy stakeholders (n = 84). HIV/syphilis testing services were implemented at a wide range of organizations which we grouped broadly as independent community-based organizations (CBOs), independent clinics, and hybrid CBO-clinic sites. From an organizational perspective, hybrid CBO-clinic sites offered the inclusive environment of an MSM CBO linked to the technical capacity and trained staff of a clinic. From a financial perspective, stakeholders expressed concern about the sustainability and effectiveness of sexual health services reliant on external funding. We identified four hybrid CBO-clinic organizations that launched pilot testing programs in order to generate revenue while expanding HIV testing.

Conclusion

Many MSM CBOs are searching for new organizational models to account for decreased external support. Hybrid CBO-clinic organizations create a strong foundation to increase HIV/syphilis testing using social entrepreneurship models in China.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0601-5) contains supplementary material, which is available to authorized users.

High prevalence of HIV and syphilis and associated factors among low-fee female sex workers in mainland China: a cross-sectional study

Background

The prevalence of HIV and syphilis among middle and high-fee female sex workers (FSWs) has been widely reported but little is known among low-fee FSWs. This study aims to determine the prevalence and associated factors of HIV and syphilis among low-fee FSWs in China.

Methods

A cross-sectional study design was used. A convenience sample of low-fee FSWs was recruited from venues by outreach workers in 12 cities. Structured questionnaire interviews and blood sampling for HIV and syphilis were carried out. Univariate and multivariate logistic regression were used for assessing potential associated factors.

Results

This study enrolled 781 low-fee FSWs. There were 37 (4.7%) HIV positive participants and 117 (15.0%) participants were infected with syphilis. Final multivariate analysis identified five factors associated with HIV infection: older age (OR:2.6, 95% CI:1.1-6.1), local household registration (OR:3.3, 95% CI:1.5-6.9), employed in Yunnan province (OR:2.7, 95% CI:1.1-6.7), soliciting in self-rented rooms and “market day” buildings (OR:3.9, 95% CI:1.5-10.0), injection drug use in the past 6 months (OR:13.5, 95% CI:4.5-40.1); and four factors associated with syphilis infection: older age (OR:1.8, 95% CI:1.2-2.9), employed in Yunnan province (OR:2.1, 95% CI:1.2-3.6), soliciting in self-rented rooms and “market day” buildings (OR:2.3, 95% CI:1.4-3.7) , and no consistent condom use with clients in the past 30 days (OR:1.6, 95% CI:1.0-2.6).

Conclusions

A high prevalence of HIV and syphilis were found among low-fee FSWs. Those soliciting in self-rented rooms and “market day” buildings with the lowest income, and injection drug users (IDUs) in this population should take priority in further intervention strategies.

Prevalence and risk factors of syphilis infection among female sex workers in Shenzhen, China: an observational study (2009-2012)

OBJECTIVE

To investigate prevalence and risk factors of syphilis infection among female sex workers (FSWs) in Shenzhen, China.

METHODS

Observational study among (2009-2012) 1653 FSWs recruited by venue-based sampling using questionnaire-based interviews for socio-demographics, behaviours and syphilis testing results. Logistic regression was used to assess risk factors of syphilis infection.

RESULTS

The overall syphilis prevalence was 4.7%, showing a slightly decreasing trend. Factors significantly associated with syphilis infection were inconsistent condom use (OR = 1.87, P = 0.015), illicit drug use (OR = 5.45, P < 0.001) and older age in years (OR = 1.08, P < 0.001). Venues where FSWs were recruited and duration of commercial sex work were not significantly associated with syphilis infection (P > 0.05).

CONCLUSIONS

Syphilis is still common among FSWs in Shenzhen, China. Current comprehensive prevention programmes (e.g. condom promotion and peer education) should be continued to maintain and increase safe sexual practices and to reduce illicit drug use among FSWs. Expanding point-of-care syphilis screening programmes may be an important strategy for early diagnosis. We recommend timely and effective treatment programmes to be linked to such screening programmes.

Spatial analysis of primary and secondary syphilis incidence in China, 2004-2010

China has recently experienced an increase in the incidence of syphilis. Effective spatial monitoring of syphilis incidence is important for successful implementation of control and prevention programmes. This study monitored county-level primary and secondary (P&S) syphilis incidence rates for all of mainland China by examining spatial patterns. Exploratory spatial data analysis (ESDA) methods were used to characterize the spatial distribution pattern of syphilis cases. During the seven-year study period, the average annual P&S syphilis incidence was 8.82 cases per 100,000 people. Using Empirical Bayes smoothed rates, the local Moran test identified many areas of high syphilis risk (all P values ≤0.01). The number of high-risk counties increased from 73 counties in 2004 to 134 counties in 2010. An eastern coastal cluster of high-risk counties persisted throughout 2004-2010. ESDA methods can assist public health officials in identifying high-risk areas. Allocating more resources to high-risk areas could more effectively reduce syphilis incidence.

Syphilis screening among 27,150 pregnant women in South Chinese rural areas using point-of-care tests

Objectives

To determine the prevalence and correlates of syphilis among pregnant women in rural areas of South China.

Methods

Point-of-care syphilis testing was provided at 71 health facilities in less developed, rural areas of Guangdong Province. Positive samples were confirmed at a local referral center by toluidine red unheated serum tests (TRUST) and Treponema pallidum particle agglutination (TPPA) tests.

Results

Altogether 27,150 pregnant women in rural Guangdong were screened for syphilis. 106 (0.39%) syphilis cases were diagnosed, of which 78 (73.6%) received treatment for syphilis. Multivariate analysis revealed that older pregnant women (31–35 years old, aOR 2.7, 95% CI 0.99–7.32; older than 35 years old, aOR 5.9, 95% CI 2.13–16.34) and those with a history of adverse pregnant outcomes (aOR 3.64, 95% CI 2.30–5.76) were more likely to be infected with syphilis.

Conclusions

A high prevalence of syphilis exists among pregnant women living in rural areas of South China. Enhanced integration of syphilis screening with other routine women's health services (OB GYN, family planning) may be useful for controlling China's syphilis epidemic.

Prioritizing congenital syphilis control in south China: a decision analytic model to inform policy implementation

BACKGROUND

Syphilis is a major public health problem in many regions of China, with increases in congenital syphilis (CS) cases causing concern. The Chinese Ministry of Health recently announced a comprehensive 10-y national syphilis control plan focusing on averting CS. The decision analytic model presented here quantifies the impact of the planned strategies to determine whether they are likely to meet the goals laid out in the control plan.

METHODS AND FINDINGS

Our model incorporated data on age-stratified fertility, female adult syphilis cases, and empirical syphilis transmission rates to estimate the number of CS cases associated with prenatal syphilis infection on a yearly basis. Guangdong Province was the focus of this analysis because of the availability of high-quality demographic and public health data. Each model outcome was simulated 1,000 times to incorporate uncertainty in model inputs. The model was validated using data from a CS intervention program among 477,656 women in China. Sensitivity analyses were performed to identify which variables are likely to be most influential in achieving Chinese and international policy goals. Increasing prenatal screening coverage was the single most effective strategy for reducing CS cases. An incremental increase in prenatal screening from the base case of 57% coverage to 95% coverage was associated with 106 (95% CI: 101, 111) CS cases averted per 100,000 live births (58% decrease). The policy strategies laid out in the national plan led to an outcome that fell short of the target, while a four-pronged comprehensive syphilis control strategy consisting of increased prenatal screening coverage, increased treatment completion, earlier prenatal screening, and improved syphilis test characteristics was associated with 157 (95% CI: 154, 160) CS cases averted per 100,000 live births (85% decrease).

CONCLUSIONS

The Chinese national plan provides a strong foundation for syphilis control, but more comprehensive measures that include earlier and more extensive screening are necessary for reaching policy goals.

Multilevel and spatial analysis of syphilis in Shenzhen, China, to inform spatially targeted control measures

OBJECTIVES

The present study investigates the varied spatial distribution of syphilis cases in Shenzhen, China, and explores the individual-, neighbourhood- and district-level factors affecting the distribution.

METHODS

This study uses spatial analysis and multi-level generalised estimating equations to explore the spatial distribution of reported syphilis cases among individuals in Shenzhen, Guangdong Province, China. The spatial distribution of primary/secondary and latent cases was investigated using the Moran's I-statistic. Primary/secondary syphilis cases were compared with all syphilis cases using a three-level model with individual (n=6496), neighbourhood (n=55) and district (n=6) levels.

RESULTS

A total of 6496 syphilis cases were reported in 2009 with 35.8% primary and secondary syphilis cases. Both primary/secondary syphilis cases (Moran's I value=0.33, p<0.01) and latent syphilis cases (Moran's I value=0.19, p<0.01) showed significant spatial clustering at the neighbourhood level. Adjusting for the number of reporting hospitals, the best model found that the following characteristics were associated with primary/secondary syphilis infection: individuals who are younger in age (p=0.003), male (p<0.001), migrant labourers (p=0.047) and those who live in districts with a higher gross domestic product (p<0.001).

CONCLUSIONS

There is substantial clustering of primary and secondary syphilis cases at the neighbourhood level in Shenzhen, suggesting the need for greater STD health service provision in these clustered neighbourhoods. Spatially targeted syphilis control measures may be useful to optimise testing, treatment and partner services.

The effect of a structural intervention for syphilis control among 3597 female sex workers: a demonstration study in South China

BACKGROUND

Syphilis has made a rapid resurgence in China, especially among high-risk groups including female sex workers (FSWs).

METHODS

Two cities in each of 3 provinces in South China were chosen and allocated to intervention or control arms. The intervention consisted of enhancing community-based syphilis screening outreach intervention with comprehensive sexually transmitted infection services at designated clinics while the control maintained routine intervention activities. Generalized linear modeling was used to examine effect of the intervention on incident syphilis infection.

RESULTS

A total of 8275 women were eligible, and 3597 women enrolled (n = 2011 in control arm, n = 1586 in intervention arm) in the study. The median follow-up duration was 375 days (interquartile range, 267–475). Syphilis incidence density in the intervention group was reduced by 70% (95% confidence interval, 53%–81%) compared with the incidence in the control arm. The syphilis prevention intervention benefits were robust among FSWs at low-tier venues, individuals with less than high school education, migrants, and women who did not report condom use during the last episode of sex.

CONCLUSIONS

Integrated sexually transmitted infection and human immunodeficiency virus prevention strategies substantially reduce syphilis incidence among FSWs, especially among those at low-tier venues. This intervention suggests the need for scaling up comprehensive FSW programs in China.

Prior HIV testing among STD patients in Guangdong Province, China: opportunities for expanding detection of sexually transmitted HIV infection

BACKGROUND

Expanding HIV testing is important among individuals at increased risk for sexual HIV transmission in China, but little is known about prior HIV testing experiences among sexually transmitted disease (STD) patients.

METHODS

This cross-sectional study of 1792 outpatients from 6 public STD clinics in Guangdong Province recorded detailed information about ever having been tested for HIV infection in addition to sociodemographic variables, health seeking, clinical STD history, and HIV stigma using a validated survey instrument.

RESULTS

A total of 456 (25.4%) of the STD patients in this sample had ever been tested for HIV infection. STD patients who were male, had higher income, more education, were at City A and City C, received STD services at public facilities, had used intravenous drugs, and had a history of an STD were more likely to ever receive an HIV test in multivariate analysis. Low perceived HIV risk was the most common reason for not receiving an HIV test. Only 7.7% of the sample reported fear of discrimination or loss of face as influencing their lack of HIV testing.

CONCLUSION

Incomplete prior HIV screening among STD patients in China suggests the need for broadening HIV testing opportunities at STD clinics and similar clinical settings attended by those with increased sexual risk.

A twin response to twin epidemics: integrated HIV/syphilis testing at STI clinics in South China

BACKGROUND

HIV testing is still stigmatized among many high-risk groups in China, whereas routine syphilis testing has been widely accepted at sexually transmitted infection (STI) clinics. This project used the platform of a rapid syphilis screening test to expand HIV test uptake. The objective of this study was to use multilevel modeling to analyze determinants of syphilis and HIV-testing uptake at STI clinics in China.

METHODS

2061 STI patients at 6 clinics in Guangdong Province were offered free rapid syphilis and free rapid HIV testing. Test uptake was defined by patient receipt of results and a multilevel model was used to analyze predictors of uptake.

RESULTS

This was the first syphilis or HIV test for the large majority (1388, 77.7%) of participants. Syphilis test uptake and HIV test uptake were high (1681, 81.6%, syphilis test uptake; 1673, 81.2% HIV test uptake). HIV test uptake was significantly concordant with syphilis test uptake (τb = 0.89, P < 0.001). The most parsimonious model of refusing HIV test uptake included the following variables: being married, having a previous HIV test, being unaccompanied, and participating in the last 2 months of the study.

CONCLUSIONS

STI clinic-based screening for syphilis and HIV represents an excellent opportunity for scaling up integrated services, especially in South China where syphilis and sexually transmitted HIV cases are both rapidly increasing. Effective integration of HIV testing into routine clinical practice requires an understanding not only of individual test uptake but also of the broader social context of HIV testing.

Syphilis test availability and uptake at medical facilities in southern China

OBJECTIVE

To examine syphilis testing capacity, screening coverage rates and types of syphilis tests used in medical facilities in southern China.

METHODS

Eleven of the 14 municipalities in Guangdong province participated. Data on syphilis testing capacity, screening coverage and types of syphilis tests used were collected from all types of public medical facilities offering prenatal care (n = 109). A total of 494 680 women who delivered during 2004-2008 were studied.

FINDINGS

In 2008, 54 196 pregnant women (43.1%) were not screened for syphilis. Among such women, 32 863 (60.6%) attended clinics without any syphilis testing capacity and 21 333 (39.4%) attended clinics that performed testing but were not screened. The likelihood of not having syphilis test capacity was much higher for hygiene stations (odds ratio, OR: 10; 95% confidence interval, CI: 4-25), services at the township level (OR: 33; 95% CI: 10-100) and services with ≤ 1000 deliveries per year (OR: 1.002; 95% CI: 1.001-1.003). These same service characteristics correlated with lower screening coverage rates (P < 0.01). Only one antenatal clinic had the capacity to conduct both treponemal and non-treponemal tests for diagnosing syphilis.

CONCLUSION

Syphilis screening is available in very few of the basic medical facilities offering prenatal care where most neonates in southern China are delivered. In light of this and of the increasing incidence of syphilis in the area, expanding point-of-care rapid syphilis testing is a priority.

Peer-based behavioral health program for drug users in China: a pilot study

BACKGROUND

Many injection drug users (IDUs) in China have high risk sexual behaviors that contribute to the spread of HIV infection. Although many IDUs in China move through drug rehabilitation centers, this opportunity for sexual health education has largely been overlooked.

METHODS

A convenience sample of 667 drug users from two rehabilitation centers in South China was recruited in the study. Two hundred and forty seven drug users from a single Guangdong Province rehabilitation center received the peer-based education intervention, while 420 drug users from another rehabilitation center received routine HIV/STI education and was used as the control. One hundred and eighty nine (22.1%) individuals refused to participate in the study. HIV/STI behavioral and knowledge domains were assessed at 3 months in rehabilitation centers after the intervention (first follow-up) and at 2-23 months in the community after release (second follow-up).

RESULTS

Drug users who completed the intervention reported more frequent condom use with casual sex partners (60.0% vs. 12.5% condom use every time, p = 0.011) and less frequent injection (56.7% vs. 26.4% no injection per day, p = 0.008) at the second follow-up compared to those in the routine education group. Loss to follow up was substantial in both control and intervention groups, and was associated with living far from the detention center and having poor HIV knowledge at baseline.

CONCLUSIONS

This study shows that rehabilitation centers may be a useful location for providing behavioral HIV/STI prevention services and referral of individuals to community-based programs upon release. More research is needed on behalf of detained drug users in China who have complex social, medical, and legal needs.

A spatial analysis of county-level variation in syphilis and gonorrhea in Guangdong Province, China

Background

Sexually transmitted infections (STI) have made a resurgence in many rapidly developing regions of southern China, but there is little understanding of the social changes that contribute to this spatial distribution of STI. This study examines county-level socio-demographic characteristics associated with syphilis and gonorrhea in Guangdong Province.

Methods/Principal Findings

This study uses linear regression and spatial lag regression to determine county-level (n = 97) socio-demographic characteristics associated with a greater burden of syphilis, gonorrhea, and a combined syphilis/gonorrhea index. Data were obtained from the 2005 China Population Census and published public health data. A range of socio-demographic variables including gross domestic product, the Gender Empowerment Measure, standard of living, education level, migrant population and employment are examined. Reported syphilis and gonorrhea cases are disproportionately clustered in the Pearl River Delta, the central region of Guangdong Province. A higher fraction of employed men among the adult population, higher fraction of divorced men among the adult population, and higher standard of living (based on water availability and people per room) are significantly associated with higher STI cases across all three models. Gross domestic product and gender inequality measures are not significant predictors of reported STI in these models.

Conclusions/Significance

Although many ecological studies of STIs have found poverty to be associated with higher reported STI, this analysis found a greater number of reported syphilis cases in counties with a higher standard of living. Spatially targeted syphilis screening measures in regions with a higher standard of living may facilitate successful control efforts. This analysis also reinforces the importance of changing male sexual behaviors as part of a comprehensive response to syphilis control in China.