Using Self-Reported Sexual Positioning as an Indicator for Rectal Chlamydia and Gonorrhea Screening Among Men Who Have Sex With Men in China: A Missed Opportunity.

BACKGROUND: Rectal Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections among men who have sex with men (MSM) are escalating public health concerns. This study aimed to explore (1) the reliability of self-reported sexual positioning as an indicator for rectal CT and NG screening, and (2) factors associated with rectal CT and NG infections in Shenzhen, China. METHODS: A cross-sectional study was conducted in 2 settings in Shenzhen, China, from April 1, 2021, to March 31, 2022. Data on sociodemographic characteristics, sexual behaviors, and basic CT knowledge were collected. Urine and self-collected rectal swabs were collected for CT and NG testing. RESULTS: In total, 195 MSM participated in the study, and 5.1% tested positive for urogenital CT, 29.2% for rectal CT, 1.0% for urogenital NG, and 8.2% for rectal NG. Among those who reported exclusively insertive anal sex, 69.2% of CT infections and 85.7% of NG infections would have remained undetected with urine testing alone. Risk factors for rectal CT infection included engaging in both insertive and receptive anal sex, with a significant association found for coinfection with rectal NG. CONCLUSIONS: Self-reported sexual positioning was found to be an unreliable indicator for CT and NG screening, as a substantial proportion of infections would have remained undetected. The findings suggest that CT and NG screening in China should be offered to all MSM regardless of self-reported sexual positioning, and that the dual CT/NG testing is recommended.

Cluster analysis for symptomatic management of Neisseria gonorrhoea and Chlamydia trachomatis in sexually transmitted infections related clinics in China.

Objective: This study aimed to perform a cluster analysis of symptoms linked with Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) and to identify which cluster of symptoms was associated with a higher risk of NG and CT. Study design: From 15 April to 16 May 2018, a cross-sectional study was conducted, and patients attending sexually transmitted infections (STI) related clinics were recruited from 22 medical institutions in six districts of Shenzhen city. Methods: A structured questionnaire was used to collect social-demographic information as well as STI symptoms, and urine samples were collected for nucleic acid detection. Cluster analysis and logistic regression were applied. Results: Among 8,207 participants, the prevalence of CT and NG infection was 9.04% (742/8,207) and 2.36% (194/8,207), respectively. Among male outpatients, four clusters with distinct symptomatic patterns were identified. Unmarried, having casual sexual partners in the past 6 months, cluster 2 (OR = 6.70, 95% CI = 3.36-13.35) and cluster 4 (OR = 24.53, 95% CI = 12.96-46.44) were risk factors associated with NG infection. Unmarried, cluster 2 (OR = 2.54, 95% CI = 1.83-3.53) and cluster 4 (OR = 3.31, 95% CI = 2.37-4.61) were risk factors associated with CT infection. Among female outpatients, five clusters with distinct symptomatic patterns were identified. Aged 24 years or below and cluster 3 (OR = 3.68, 95% CI = 1.61-8.39) were risk factors associated with NG infection. Aged 24 years or below, unmarried, having a high school/secondary technical school education, and having junior high school or below education were risk factors associated with CT infection. Conclusion: The cluster of symptoms integrated into risk assessment for CT and NG infections suggests a new strategy of symptomatic management. Healthcare providers in STI clinics and resource-limited places may use this strategy to identify more potential patients and deliver adequate, acceptable, and equitable STI care for outpatients with a high risk of STI.

Acceptability of rectal self-sampling in non-clinical venues for chlamydia and gonorrhea testing among men who have sex with men: A cross-sectional study in Shenzhen, China.

Background: Rectal Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections among men who have sex with men (MSM) have become an increasingly important concern. The study aimed to explore (1) the acceptability of rectal self-sampling for chlamydia and gonorrhea testing among MSM in non-clinical venues in Shenzhen city, China; (2) factors associated with the acceptability of rectal self-sampling; and (3) factors associated with rectal CT and NG infections, respectively. Methods: This cross-sectional study was conducted in two non-clinical settings in Shenzhen, China, from April 2021 to October 2021. Mixed-effects logistic regression analysis was performed to explore the factors associated with acceptance of rectal self-collection for CT and NG testing. Results: Of the 306 MSM who were offered to perform rectal self-sampling, 133 (43.46%) accepted, and 96.24% (128/133) of them successfully provided a valid rectal sample. The prevalence of urogenital CT and NG infections among 303 MSM was 4.29 and 0.66%, respectively. The prevalence of rectal CT and NG infections among 128 participants was 31.25 and 9.38%, respectively. Participants having been diagnosed with HIV infection showed a higher acceptance of rectal self-collection for CT and NG testing. Conclusion: This study reported that rectal self-sampling in non-clinical venues for CT and NG testing among MSM was barely acceptable and feasible in China. Most CT and NG infections would have been missed if urethral screening was offered alone, which implies that the CT and NG screening should be scaled up in the above setting. Integrating free CT tests into regular STI interventions for MSM could also be considered.

High chlamydia infection and its associated factors among patients seeking clinic-based STI services in Southern China: A preliminary cross-sectional study.

Objective: Chlamydia trachomatis (CT) infection is one of the most common sexually transmitted infections (STIs) worldwide. This study aimed to provide prevalence and associated factors data among patients seeking clinic-based STI services for estimating the disease burden of CT. Study design and method: A cross-sectional survey was conducted among patients attending clinics for STI services. Patients' social-demographic and behavioral information was collected and CT infection was determined by nucleic acid amplification test (NAAT) with self-collected urine specimens. Associated factors were identified using logistic regression. Results: Among the 8,324 participants, the overall prevalence was 9.0% with 10.7% for males and 8.3% for females respectively. Multivariate analysis showed that aged < 24 [adjusted odds ratio (aOR) = 1.27, 95% confidence interval (CI) = 1.01-1.59], being unmarried (aOR = 1.64, 95%CI = 1.35-2.00), having junior high school or below education level (aOR = 1.47, 95%CI = 1.13-1.91), having no access to health insurance (aOR = 1.27, 95%CI = 1.07-1.51), and being positive for Neisseria gonorrhoeae (NG, aOR = 4.49, 95%CI = 3.25-6.21) were significantly associated with CT infection. Conclusion: We found that CT infection is prevalent among patients seeking clinic-based STI services in Southern China. Targeted interventions could be implemented for patients with a higher risk of CT infection including those aged < 24, being unmarried, having junior high school or below education level, having no access to health insurance, and being positive for NG. In addition, routine CT screening could be considered a public health strategy by the government.

Chlamydia-related knowledge, opinion to opportunistic testing, and practices of providers among different sexually transmitted infections related departments in hospitals in Shenzhen city, China.

BACKGROUND: Chlamydia trachomatis (CT) infection could lead to seriously adverse outcomes if left untreated. This study aimed to determine CT-related knowledge, opinion to testing, and practices of providers among different sexually transmitted infections (STI) related departments in hospitals in Shenzhen city, China, and also to explore the differences in these responses. MATERIALS AND METHODS: From 1st April 2018 to 15th April 2018, a cross-sectional study was conducted in Shenzhen and 64 of 66 hospitals agreed to participate in this study. In the hospital sites, all the providers from the department of obstetrics and gynecology, department of dermatology and venereology, department of urology, and anorectal surgical department were recruited. A structured paper-based questionnaire was used to obtain data on CT-related information. RESULTS: A total of 355 providers from 64 hospitals participated in the current study. Compared to providers from the department of dermatology and venereology, those from the department of obstetrics and gynecology (OR = 0.31, 95% CI 0.16-0.62), department of urology (OR = 0.32, 95% CI 0.16-0.65), and anorectal surgical department (OR = 0.25, 95% CI 0.09-0.71) were less likely to identify that "Be in a long-term mutually monogamous relationship with a partner who has been tested and has negative STI test results." is an appropriate way for a sexually active person to reduce risk of getting CT. Also, those from the department of obstetrics and gynecology (OR = 0.45, 95% CI 0.23-0.87) were less likely to identify that "Use latex condoms the right way every time you have sex" is another appropriate way. A high proportion of providers agreed that all sexually active patients attending to their department should be screened regularly (77.1%), and they are willing to offer opportunistic CT screening (96.0%). Only 11.4% of respondents correctly identified that the appropriate time frame of the CT retesting is three months. CONCLUSIONS: Providers among STI-related departments in hospitals showed a very high willingness to offer opportunistic CT screening. However, this study showed important gaps in providers' knowledge and practices in China, targeted training in CT-related knowledge and practice is urgently needed.

Associated factors of willingness to undergo routine chlamydia trachomatis screening among hospital-based patients in Shenzhen, China: a cross-sectional study.

BACKGROUND: Chlamydia trachomatis (CT) is a common sexually transmitted infection (STI) with significant morbidity. The study aimed to explore the willingness to undergo routine CT screening and its associated factors among hospital-based patients in Shenzhen. METHODS: We used data from the Shenzhen Gonorrhea and Chlamydia Intervention Programme. Participants were recruited with a stratified purposeful sampling design from 1 April 2018 to 16 May 2018. A structured questionnaire was used to obtain data on baseline characteristics and CT-related participant information. RESULTS: Of the 16,546 participants, 64.79% were women, with a mean age of 31.85 ± 7.31 of all participants. Of the participants, 88.78% were willing to undergo routine CT screening. According to multivariate logistic regression analyses, willingness to undergo routine CT screening was associated with the following (P < 0.05): being a woman (AOR = 1.53, 95% CI = 1.34-1.75), one year or more residency in Shenzhen (AOR = 1.64, 95% CI = 1.37-1.95), any secondary education (AOR = 2.46, 95% CI = 1.92-3.15), monthly income ≥ RMB 10,000 (AOR = 1.24, 95% CI = 1.01-1.51), having forgotten CT diagnosis history (AOR = 1.42, 95% CI = 1.12-1.79), without current STI-related symptoms (AOR = 1.24, 95% CI = 1.10-1.41), and having correct understanding of the sequelae of CT infection (AOR = 1.68, 95% CI = 1.39-2.03). CONCLUSION: This study reported high willingness to undergo routine CT screening among hospital-based patients in Shenzhen, and provided evidence for the promotion and the implementation of strategies and recommendations on routine CT screening in China.

High Willingness to Participate in Partner Notification among Women Attending Reproductive Health and STI Clinics in Shenzhen, China: A Cross-Sectional Study.

Genital Chlamydia trachomatis (CT) is one of the most common sexually transmitted infections (STI) worldwide. We explored the factors associated with willingness to participate in partner notification (PN) among women attending reproductive health and STI clinics in Shenzhen, China. An anonymous questionnaire was used to collect the sociodemographic characteristics, STI histories, and willingness to participate in routine CT screening and partner notification. In total, 87.31% (n = 10,780) of participants were willing to notify their sex partner(s) if they were diagnosed with a CT infection. Willingness to complete PN was significantly associated with: being married, residing in Shenzhen ≥1 year, having completed junior college or higher, not currently reporting STI-related symptoms, willing to have routine CT screening, and having a correct understanding of the health sequelae of CT infection. Nearly all women surveyed at reproductive health and STI clinics in Shenzhen reported willingness to complete PN. Promoting PN in these settings could help detect a large number of additional CT cases. Our findings provide evidence and implications for public health interventions on PN and suggest that targeted interventions are urgently needed for particular subpopulations including those not currently married, with shorter residency, lower education, and less awareness about the dangers of CT infection.

Reduced Expression of a Novel Midgut Trypsin Gene Involved in Protoxin Activation Correlates with Cry1Ac Resistance in a Laboratory-Selected Strain of Plutella xylostella (L.).

Bacillus thuringiensis (Bt) produce diverse insecticidal proteins to kill insect pests. Nevertheless, evolution of resistance to Bt toxins hampers the sustainable use of this technology. Previously, we identified down-regulation of a trypsin-like serine protease gene PxTryp_SPc1 in the midgut transcriptome and RNA-Seq data of a laboratory-selected Cry1Ac-resistant Plutella xylostella strain, SZ-R. We show here that reduced PxTryp_SPc1 expression significantly reduced caseinolytic and trypsin protease activities affecting Cry1Ac protoxin activation, thereby conferring higher resistance to Cry1Ac protoxin than activated toxin in SZ-R strain. Herein, the full-length cDNA sequence of PxTryp_SPc1 gene was cloned, and we found that it was mainly expressed in midgut tissue in all larval instars. Subsequently, we confirmed that the PxTryp_SPc1 gene was significantly decreased in SZ-R larval midgut and was further reduced when selected with high dose of Cry1Ac protoxin. Moreover, down-regulation of the PxTryp_SPc1 gene was genetically linked to resistance to Cry1Ac in the SZ-R strain. Finally, RNAi-mediated silencing of PxTryp_SPc1 gene expression decreased larval susceptibility to Cry1Ac protoxin in the susceptible DBM1Ac-S strain, supporting that low expression of PxTryp_SPc1 gene is involved in Cry1Ac resistance in P. xylostella. These findings contribute to understanding the role of midgut proteases in the mechanisms underlying insect resistance to Bt toxins.

Silicon amendment to rice plants impairs sucking behaviors and population growth in the phloem feeder Nilaparvata lugens (Hemiptera: Delphacidae).

The brown planthopper (BPH), Nilaparvata lugens (Stål), is a migratory and destructive sucking insect pest of rice. Silicon (Si) amendment to plants can confer enhanced resistance to herbivores and is emerging as a novel approach for pest management. In the present study, we tested the effects of Si addition at 0.16 (low) and 0.32 (high) g Si/kg soil on sucking behaviors and population growth in BPH. Si amendment increased Si content in rice stems and extended non-probing event and phloem puncture followed by sustained phloem ingestion over that in the no-Si-addition control. High Si addition rate prolonged the stylet pathway and the time needed to reach the first phloem puncture, shortened durations of phloem puncture and phloem ingestion, and decreased the proportion of individuals that produced sustained phloem ingestion. BPH female feeding on and preference for plants with the high Si addition rate were also reduced. As a result, Si application significantly decreased BPH population growth rates while increased population doubling time. These results indicate that Si amendment, especially at the high rate, confers enhanced rice plant resistance to BPH through impairment of BPH feeding. Our results highlight the potential of Si amendment as an alternative for BPH management.

Defense Responses in Rice Induced by Silicon Amendment against Infestation by the Leaf Folder Cnaphalocrocis medinalis.

Silicon (Si) amendment to plants can confer enhanced resistance to herbivores. In the present study, the physiological and cytological mechanisms underlying the enhanced resistance of plants with Si addition were investigated for one of the most destructive rice pests in Asian countries, the rice leaf folder, Cnaphalocrocis medinalis (Guenée). Activities of defense-related enzymes, superoxide dismutase, peroxidase, catalase, phenylalanine ammonia-lyase, and polyphenol oxidase, and concentrations of malondialdehyde and soluble protein in leaves were measured in rice plants with or without leaf folder infestation and with or without Si amendment at 0.32 g Si/kg soil. Silicon amendment significantly reduced leaf folder larval survival. Silicon addition alone did not change activities of defense-related enzymes and malondialdehyde concentration in rice leaves. With leaf folder infestation, activities of the defense-related enzymes increased and malondialdehyde concentration decreased in plants amended with Si. Soluble protein content increased with Si addition when the plants were not infested, but was reduced more in the infested plants with Si amendment than in those without Si addition. Regardless of leaf folder infestation, Si amendment significantly increased leaf Si content through increases in the number and width of silica cells. Our results show that Si addition enhances rice resistance to the leaf folder through priming the feeding stress defense system, reduction in soluble protein content and cell silicification of rice leaves.

Analysis of the sex ratio of reported gonorrhoea incidence in Shenzhen, China.

OBJECTIVE: To assess the clinical process of gonorrhoea diagnosis and report in China, and to determine the difference of sex ratio between reported incidence based on reporting data and true diagnosis rate based on reference tests of gonorrhoea. SETTING: A total of 26 dermatology and sexually transmitted disease (STD) departments, 34 obstetrics-gynaecology clinics and 28 urology outpatient clinics selected from 34 hospitals of Shenzhen regarded as our study sites. PARTICIPANTS: A total of 2754 participants were recruited in this study, and 2534 participants completed the questionnaire survey and provided genital tract secretion specimens. There were 1106 male and 1428 female participants. Eligible participants were patients who presented for outpatient STD care at the selected clinics for the first time in October 2012 were at least 18 years old, and were able to give informed consent. OUTCOME MEASURES: Untested rate, true-positive rate, false-negative rate and unreported rate of gonorrhoea, as well as reported gonorrhoea incidence sex ratio and true diagnosis sex ratio were calculated and used to describe the results. RESULTS: 2534 participants were enrolled in the study. The untested rate of gonorrhoea among females was significantly higher than that among males (female 88.1%, male 68.3%, p=0.001). The male-to-female sex ratios of untested rate, true-positive rate, false-negative rate and unreported rate were 1:1.3, 1.2:1, 1:1.6 and 1:1.4, respectively. The reported gonorrhoea incidence sex ratio of new diagnosed gonorrhoea was 19.8:1 (male vs female: 87/1106 vs 5/1420), while the true diagnosis sex ratio was 2.5:1 (male vs female: 161/1106 vs 84/1420). These data indicate that the sex ratio of reported gonorrhoea incidence has been overestimated by a factor of 7.9 (19.8/2.5). CONCLUSIONS: We found the current reported gonorrhoea incidence and sex ratios to be inaccurate due to underestimations of gonorrhoea incidence, especially among women.

Silicon-mediated resistance in a susceptible rice variety to the rice leaf folder, Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae).

The rice leaf folder, Cnaphalocrocis medinalis (Guenée), is one of the most destructive rice pests in Asian countries. Rice varieties resistant to the rice leaf folder are generally characterized by high silicon content. In this study, silicon amendment, at 0.16 and 0.32 g Si/kg soil, enhanced resistance of a susceptible rice variety to the rice leaf folder. Silicon addition to rice plants at both the low and high rates significantly extended larval development and reduced larval survival rate and pupation rate in the rice leaf folder. When applied at the high rate, silicon amendment reduced third-instars' weight gain and pupal weight. Altogether, intrinsic rate of increase, finite rate of increase and net reproduction rate of the rice leaf folder population were all reduced at both the low and high silicon addition rates. Although the third instars consumed more in silicon-amended treatments, C:N ratio in rice leaves was significantly increased and food conversion efficiencies were reduced due to increased silicon concentration in rice leaves. Our results indicate that reduced food quality and food conversion efficiencies resulted from silicon addition account for the enhanced resistance in the susceptible rice variety to the rice leaf folder.

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.

[Spatial and temporal patterns of primary and secondary syphilis in Shenzhen, China].

OBJECTIVE: To learn the spatial and temporal patterns of primary syphilis and secondary syphilis in Shenzhen and to provide evidence for carrying out further research on syphilis. METHODS: Primary syphilis and secondary syphilis cases among residents in Shenzhen between 2005 and 2009 (n = 11 303) were geocoded at street office level (n = 55) based on residence at the time of diagnosis. Both spatial and space-time scan statistics were used to identify clusters of street office by using SaTScan software. RESULTS: In the purely spatial analyses, clusters were seen in the junction of the Baoan district and Nanshan district (Xinan, Xixiang, Nanshan and Nantou street office) and in the region near Hong Kong (Dongmen, Shekou, and Futian street office), as well as in the other streets where entertainment industry was relatively developed (Longhua, Huafu, Huangbei and Cuizu street office). The clusters had not changed much in the first four years, but nine clusters appeared in 2009. Annually, the most likely clusters were located in Longhua (2005, P ≤ 0.001, RR = 3.34), Bamboo (2006, P ≤ 0.001, RR = 9.59), Huafu (2007, 2008 years, P ≤ 0.001, RR values were 4.18 and 4.75) and Cuizu (2009, P ≤ 0.001, RR = 8.02). In the space-time scan analysis, we found 16 significant clusters, which were similar to the pure spatial analyses. However, regional difference were also found, with the most likely cluster was the Guiyuan street office in 2006. CONCLUSION: Spatial and space-time scan statistics seemed to be effective ways in describing the circular disease clusters. We have had a better understanding on spatial and temporal patterns of primary syphilis and secondary syphilis in Shenzhen through spatial and space-time scan statistics of syphilis surveillance data in the recent years. The changes of spatial and temporal patterns of primary syphilis and secondary syphilis were also described by SaTScan software, which also provided useful reference for the preventive strategies on sexually transmitted diseases as well as on HIV. Useful information was also provided for financial investment and cost-effective studies.

A risk model for congenital syphilis in infants born to mothers with syphilis treated in gestation: a prospective cohort study.

OBJECTIVE: To explore the risk factors underlying congenital syphilis (CS) and to build a hazards model to assess the risk of CS in offspring born to mothers with syphilis treated in gestation. METHODS: This prospective study observed 554 pregnant women with syphilis and their offspring recruited from August 2002 to May 2007 in Shenzhen Centre for Chronic Disease Control and Prevention. After treatment, all the women were followed up until the diagnosis of CS in their offspring was confirmed or denied. Comparisons were made between women bearing infants with CS and women bearing infants without CS to reveal the risk factors for CS. ORs and their 95% CI were calculated for each risk factor by using logistical regression analysis. RESULTS: Twenty-nine (5.2%) infants were diagnosed with CS. Univariable analyses showed that the reciprocal logarithm of the titre of non-treponemal antibodies in mothers (log (1/T); OR=11.18, p<0.001), gestational week (GW) at treatment (OR=1.10, p<0.001) and the interaction between these two variates (OR=1.09, p<0.001) was associated with CS. Multivariable analysis showed that only the interaction was significantly associated with CS (OR=1.09, p=0.047). CONCLUSIONS: The risk of CS could be predicted by the interaction between GW x log (1/T). Early treatment given to women with syphilis during antenatal care may be the only effective method to decrease the risk of CS.