Yue-Ping Yin

Point-of-Care Tests to Strengthen Health Systems and Save Newborn Lives: The Case of Syphilis

Rosanna Peeling and colleagues describe their experience of introducing point-of-care testing to screen for syphilis in pregnant women living in low- and middle-income countries.

The epidemic of sexually transmitted infections in China: implications for control and future perspectives

China has experienced an increasing epidemic of sexually transmitted infections (STIs), including HIV. High risk groups likely to be infected include female sex workers (FSWs) and their clients, men who have sex with men (MSM), drug users and migrant workers. Prevention can be achieved through education of the population, condom promotion, early detection of symptomatic and asymptomatic people, and effective diagnosis and treatment of these patients and their partners. This article aims to describe the profile of the epidemic in high-risk groups in China as well as to detail the contributing factors and the implications for control. Programmes for the control of STIs should be immediate priorities in China, and primary and secondary prevention strategies are vital to this process.

Distribution Study of Chlamydia trachomatis Serovars among High-Risk Women in China Performed Using PCR-Restriction Fragment Length Polymorphism Genotyping

ABSTRACT This was one of the first epidemiological studies in China focused on genital Chlamydia trachomatis serotype distribution in high-risk female populations using omp1 gene-based restriction fragment length polymorphism analysis. One thousand seven hundred seventy cervical swab samples from women attending sexually transmitted disease clinics and female sex workers in six cities in China (Shenzhen and Guangzhou in southern China, Nanjing and Shanghai in eastern China, and Nanning and Chengdu in southwestern China) were subjected to serovar genotyping. The proportion of omp1 genes successfully amplified in 240 C. trachomatis plasmid-positive samples was 94.2% (226/240). Serotypes E (n = 63; 27.9%), F (n = 53; 23.5%), G (n = 28; 12.4%), and D (n = 25; 11.1%) were most prevalent. Though there was no significant difference in the geographic distribution of C. trachomatis, serotype E was predominant in the South (32.1%) and East (27.1%), while serotype F was predominant in the Southwest (28.3%). Serotype F infection was associated with young age and single status. Serovar G was associated with lower abdominal pain; 47.5% of asymptomatic patients were infected with serovar E. These results provide information on distribution of genital C. trachomatis serotypes among high-risk women in China and indicate that high-risk women, including those who are asymptomatic, can be infected with multiple serovars of C. trachomatis, revealing exposure to multiple sources of infection. Although the scope for generalizations is limited by our small sample size, our results showing clinical correlations with genotypes are informative.

Clinic-based evaluation of Clearview Chlamydia MF for detection of Chlamydia trachomatis in vaginal and cervical specimens from women at high risk in China

Objectives: To determine the performance of a rapid Chlamydia trachomatis (CT) test (Clearview Chlamydia MF) compared to the current “gold standard” (Roche Amplicor CT assay) test, and to assess acceptability of the tests to patients. Methods: A total of 1497 women at sexually transmitted diseases (STD) clinics or re-education centres in six urban cities (Shanghai, Nanjing, Shenzhen, Guangzhou, Chengdu and Fuzhou) in China participated in the study. Three vaginal and three cervical swabs were collected from each participant. Rapid CT tests were performed locally on the first vaginal and cervical swabs and the results were read independently by two staff members. The second and third swabs were randomised for performing the Roche CT assay at the National STD Reference Laboratory. Acceptability of the rapid tests to patients was determined by asking patients in clinics about their willingness to wait for the results. Results: The prevalence of CT was 13.2% (197/1497), as determined by the Roche assay with cervical specimens. CT was detected in 78 vaginal and 127 cervical specimens by the rapid test and the positive rates determined with cervical specimens were significantly higher than those with vaginal specimens (p<0.001). There was good agreement between the results read by two independent staff for either vaginal or cervical specimens (both κ = 0.98, p<0.001). Sensitivities for vaginal and cervical specimens were 32.8% and 49.7%, respectively, and specificities were 99.2% and 97.9%, respectively. The positive predictive value was 85.7% for vaginal and 78.4% for cervical specimens. The vast majority of the patients (99.1%) were willing to wait up to two hours for the results. Conclusion: Clearview Chlamydia MF, while yielding a rapid result and requiring minimal laboratory facilities, had unacceptably low sensitivity compared to a nucleic acid amplification test. Rapid tests yielding results within one hour are generally accepted by the clients.

A Dual Point-of-Care Test Shows Good Performance in Simultaneously Detecting Nontreponemal and Treponemal Antibodies in Patients With Syphilis: A Multisite Evaluation Study in China

BACKGROUND Rapid point-of-care (POC) syphilis tests based on simultaneous detection of treponemal and nontreponemal antibodies (dual POC tests) offer the opportunity to increase coverage of syphilis screening and treatment. This study aimed to conduct a multisite performance evaluation of a dual POC syphilis test in China. METHODS Participants were recruited from patients at sexually transmitted infection clinics and high-risk groups in outreach settings in 6 sites in China. Three kinds of specimens (whole blood [WB], fingerprick blood [FB], and blood plasma [BP]) were used for evaluating sensitivity and specificity of the Dual Path Platform (DPP) Syphilis Screen and Confirm test using its treponemal and nontreponemal lines to compare Treponema pallidum particle agglutination (TPPA) assay and toluidine red unheated serum test (TRUST) as reference standards. RESULTS A total of 3134 specimens (WB 1323, FB 488, and BP 1323) from 1323 individuals were collected. The sensitivities as compared with TPPA were 96.7% for WB, 96.4% for FB, and 94.6% for BP, and the specificities were 99.3%, 99.1%, and 99.6%, respectively. The sensitivities as compared with TRUST were 87.2% for WB, 85.8% for FB, and 88.4% for BP, and the specificities were 94.4%, 96.1%, and 95.0%, respectively. For specimens with a TRUST titer of 1:4 or higher, the sensitivities were 100.0% for WB, 97.8% for FB, and 99.6% for BP. CONCLUSIONS  DPP test shows good sensitivity and specificity in detecting treponemal and nontreponemal antibodies in 3 kinds of specimens. It is hoped that this assay can be considered as an alternative in the diagnosis of syphilis, particularly in resource-limited areas.

Sexually transmitted infections among pregnant women attending an antenatal clinic in Fuzhou China.

Objective: To determine the prevalence of sexually transmitted infections (STIs) among women attending an antenatal clinic in urban China and to show whether reported symptoms and findings on clinical examination predicted STIs in this population. Study Design: Cross-sectional descriptive study was conducted among 504 pregnant women attending an antenatal clinic in Fuzhou, China. Structured questionnaires were used to collect demographic and behavioral information, and clinical and gynecologic examinations were performed to detect clinical signs of STIs. Blood samples, vaginal swabs, and cervical swabs were collected, respectively, to test for antibodies to syphilis, culture Trichomonas vaginalis (T. vaginalis), and perform PCR to detect Chlamydia trachomatis (C. trachomatis) and Neisseria gonorrhoeae (N. gonorrhoeae). Results: C trachomatis was detected in 51 (10.1%), N gonorrhoeae in 4 (0.8%), T vaginalis in 16 (3.2%), and syphilis in 1 (0.2%) of the 504 pregnant women. Fifty-two (73%) of 71 women with any STI were asymptomatic. Multiple logistic regression analysis indicated that age ≤25 years (OR = 2.72) and monthly income >RMB 2000 yuan (OR = 3.57) were significant independent risk factors for chlamydial infection (P < 0.05). The reported symptom of vaginal discharge or the clinical sign of either vaginal or cervical discharge poorly predicted infection with C trachomatis, N gonorrhoeae, or T vaginalis, with a positive predictive value <25% for each STI. Conclusion: A substantial prevalence of STIs, including a large proportion of asymptomatic infections, was found among pregnant women in the study area. These results support a strategy of screening pregnant women for bacterial STIs (followed by treatment of infections), which could be integrated into routine pregnancy care in China.

Prevalence of sexually transmitted infections among long-distance truck drivers in Tongling China.

Little is known about sexually transmitted infections (STIs), including HIV, among truck drivers in China. A cross-sectional study was conducted among truck drivers in Tongling of Anhui Province. A total of 550 truck drivers were interviewed with a structured questionnaire, and blood samples were collected and tested for HIV, syphilis, and herpes simplex virus 2 (HSV-2), and urine specimens for Neisseria gonorrhoeae and Chlamydia trachomatis. Prevalence was 10.6% for C. trachomatis and 8.1% for N. gonorrhoeae. Antibodies for syphilis were found in 0.7% and for HSV-2 in 4.4%, and none was positive for HIV. About 92 (17.4%) truck drivers had at least one STI. There was no statistically significant association between sociodemographic, occupation or behavioural variables and the presence of a positive test for any STI. Our study suggests a high prevalence of STIs, particularly bacterial infections, among the truck drivers, indicating the need for health education, behavioural change interventions and STI care services in this population.

Prevalence of syphilis infection in different tiers of female sex workers in China: implications for surveillance and interventions

BackgroundSyphilis has made a dramatic resurgence in China during the past two decades and become the third most prevalent notifiable infectious disease in China. Female sex workers (FSWs) have become one of key populations for the epidemic. In order to investigate syphilis infection among different tiers of FSWs, a cross-sectional study was conducted in 8 sites in China.MethodsSerum specimens (n = 7,118) were collected to test for syphilis and questionnaire interviews were conducted to obtain socio-demographic and behavioral information among FSWs recruited from different types of venues. FSWs were categorized into three tiers (high-, middle- and low-tier FSWs) based on the venues where they solicited clients. Serum specimens were screened with enzyme-linked immunosorbent assay (ELISA) for treponemal antibody followed by confirmation with non-treponemal toluidine red unheated serum test (TRUST) for positive ELISA specimens to determine syphilis infection. A logistic regression model was used to determine factors associated with syphilis infection.ResultsOverall syphilis prevalence was 5.0% (95%CI, 4.5-5.5%). Low-tier FSWs had the highest prevalence (9.7%; 95%CI, 8.3-11.1%), followed by middle-tier (4.3%; 95%CI, 3.6-5.0%, P < 0.001) and high-tier FSWs (2.2%; 95%CI, 1.6-2.9%, P < 0.001). Factors independently associated with syphilis infection included older age, lower education level, geographic location, lower tier of typology, and injection drug use.ConclusionsThis multi-site survey showed a high prevalence of syphilis infection among FSWs and substantial disparities in syphilis prevalence by the tier of FSWs. The difference in syphilis prevalence is substantial between different tiers of FSWs, with the highest rate among low-tier FSWs. Thus, current surveillance and intervention activities, which have low coverage in low-tier FSWs in China, should be further examined.

Surveillance of antibiotic resistance of Neisseria gonorrhoeae isolates in China, 1993-1998.

Background The prevalence of sexually transmitted diseases (STDs) has been increasing in China since the 1980s. Because gonorrhea is the most frequently reported STD there, information on the antimicrobial susceptibility of Neisseria gonorrhoeae will aid in its control. Goal To investigate the antimicrobial susceptibility of N gonorrhoeae isolates in China and to provide data for formulation of treatment guidelines and control policies. Methods The agar dilution technique was used to determine antimicrobial susceptibility, and acidimetric method was used to test for penicillinase-producing N gonorrhoeae. Results A total of 3186 gonococcal isolates were tested during the 6-year study period. The rate of resistance to penicillin was 66.70%; 8.14% of isolates were penicillinase-producing N gonorrhoeae. The percentage of tetracycline-resistant isolates was 92.03%, and that of highly tetracycline-resistant isolates was 4.65%. The rate of resistance to ciprofloxacin was also relatively high (34.25%). The rates of resistance to spectinomycin and ceftriaxone were 0.44% and 0.57%. Conclusions The gonococcal isolates in China are relatively highly resistant to penicillin, tetracycline, and ciprofloxacin, but most of them are still susceptible to spectinomycin and ceftriaxone. Standardized treatment of gonorrhea is needed to prevent further spread of resistant gonococcal strains.

Molecular Typing of treponema pallidum Causing Early Syphilis in China: A Cross-sectional Study

Background: There have been limited data on molecular epidemiology of syphilis in China. This study aimed to analyze strain type distribution of Treponema pallidum causing early syphilis across geographic areas in China using an enhanced method. Methods: Genital samples were collected from patients in East, South, and North China. Positive DNA of T. pallidum was analyzed by arp, tpr, and tp0548 genes. Results: Sufficient DNA for full molecular typing existed in 197 of 324 samples, and 27 strain types were identified. A range of 3 to 20 repeats (except 4, 11, and 19 repeats) and 25 repeats were found for the 60-bp tandem repeats of the arp gene. This was the first time the 9 and 25 repeats were detected. For the RFLP analysis of the tpr genes, patterns a, d, h, j, and l were identified. This was the first time the h, j, and l patterns were observed in China. For the sequence analysis of the tp0548 gene, sequences c, e, and f were identified. Strain type distribution was significantly different across geographic areas (&khgr;2 = 20.6, P = 0.006). Overall, 14d/f was most predominant (39% of fully typed samples, 95% CI = 32%–46%); 13d/f, 15d/f, and 16d/f were next most common (each 13% of fully typed samples, 95% CI = 9%–18%). Conclusions: There is substantial genetic diversity of T. pallidum in China. The broad and ununiform distribution of strain types may reflect differences in regional sexual network patterns. Predominance of few strain types may indicate a linked transmission.