Misdiagnosis of Sexually Transmitted Diseases in Hong Kong Outpatient Private Healthcare

Background and objective: Early and accurate diagnosis is one of the critical requirements for successful management of all diseases. Yet, delayed diagnosis and misdiagnosis remain as vital problems, consequently impose adverse effects on patient treatment. Sexually transmitted disease (STD) is one of the most common infectious diseases, and more than one million of STD cases are acquired every day globally. Misdiagnosis of STD inevitably exists, therefore should not be overlooked. Being a medical diagnostic laboratory providing various STDs diagnosing service in Hong Kong, we aimed to determine the misdiagnosis rate of STDs and investigate the possible underlying cause. Methods: Specimens were collected for STD diagnosis from multiple clinics during 1 June 2021 to 20 October 2021 from different clinics and hospitals were included in the study. DNA extraction was performed using magnetic bead based method;then the extracted DNA was tested using the DiagCor GenoFlowTM STD Array kit to detect the existence of any targeted pathogens. Results: 1459 specimens were collected and included during the designated time period, with 643 specimens found to be positive with at least one targeted STD pathogen. 494 of these were found to be aligned with test ordered by physicians, and the remaining 149 positive cases had at least one pathogen detected but not requested to be tested by the physicians resulting in misdiagnosis. The overall misdiagnosis rate was determined to be 23.2% (149/643), with high frequency of misdiagnosis occurred to tests ordered for one to three pathogens detection. Also, Ureaplasma urealyticum and/or Ureaplasma parvum (UU/UP) was the commonest pathogen detected in this study. Conclusion: The findings suggested incorrect test selection made by physicians was one of the major reasons of STDs misdiagnosis in outpatient settings. To reduce diagnostic errors in STD diagnosis, physicians are encouraged to select and request test that allow detection of multiple pathogens, as co-infection of multiple pathogens in STD patients is commonly observed. The correct selection of test would not only benefit the patient, but also the public health.

Socio-Demographic, Clinical, and Hygiene Profile of Syndromically Managed Sexually Transmitted Diseases: A Cross Sectional Study in a Tertiary Care Center in India

Background: Sexually transmitted diseases are one of the several major public health concerns, the burden of which is borne by low- and middle-income countries like India. Purpose: The purpose is to evaluate the relationship between menstrual and sanitary hygiene and sexually transmitted diseases (STD) based on syndromic diagnosis Methods: An out-patient department (OPD) based cross sectional survey to determine these associations, if any exist, which would help critically analyze syndromic management. STD was reported by the presence of vaginal/cervical/urethral discharge with or without irritation and itching, lower abdominal pain and ulcer. Results: The prevalence of STD was 66.84% with the most commonly reported symptoms being discharged (31.18%), followed by abdominal pain (17.92%) and itching/irritation (12.90%), with ulcer (4.83%) being the least reported symptom. Perimenopausal age ((AOR: 0.420 [CI: 0.189 - 0.915];p = 0.030), higher grades of education ((AOR: 0.228 [CI: 0.119 - 0.424];p < 0.001) for secondary), urban residency (AOR: 0.435 [CI: 0.686 - 2.733];p < 0.001), and contraception use (AOR: 0.531 [CI: 0.308 - 0.887];p = 0.018) were associated with lesser odds of presenting with an STD symptom. Belonging to a minority religious community (AOR: 7.20 [CI: 1.866 - 48.251];p < 0.012) or backward castes (AOR: 3.753 [CI: 1.587 - 10.144];p < 0.001), having similar illness (AOR: 4.205 [CI: 2.795 - 6.439];p < 0.001) or having an invasive gynecological procedure done in the past one year (AOR: 1.953 [CI: 1.184 - 3.295];p = 0.010) and washing the reusable sanitary material only with water (AOR: 4.900 [CI: 2.701 - 9.116];p < 0.001) as compared to washing it with water and soap, had a higher association with presenting with STD symptoms. Stratified analysis also showed that women presenting discharge (AOR: 2.049 [CI: 1.343 - 3.146] for vaginal and cervical;AOR: 1.426 [CI: 0.826 - 2.482] for urethral) were more likely to not have a toilet facility in an accessible condition. Women with sanitary napkin use had lesser odds (AOR: 0.780 [CI: 0.516 - 1.180];p = 0.293) of presentation for STD in OPD than women who used other material. Conclusion: To better manage the group of diseases that may present with symptoms of STD under syndromic approach, we propose interventions such as menstrual hygiene education and promotion of the use of sanitary napkins among women especially those belonging to lower socio-economic sections of the society.

Global epidemiology of sexually transmitted diseases

Sexually transmitted diseases （STDs） are among the first ten causes of unpleasant diseases in young adult males in developing countries and the second major cause of unpleasant diseases in young adult women. Adolescents and young adults （15-24 years old） make up only 25% of the sexually active population, but represent almost 50% of all new acquired STDs. In general, STDs are epidemics and present an enormous health and economic consequences. An adequate screening for STDs should be done on a routine basis in every part of the world. Many STDs are asymptomatic and therefore can difficult to control. The purpose of reporting of STDs is to ensure that persons who are infected will be quickly diagnosed and appropriately treated to control the spread of infection and also so that partners are notified, tested and appropriately treated. It is estimated that reported cases of STDs represent only 50%-80% of reportable STD infections in the United States, reflecting limited screening and low disease reporting. High-risk sexual behavior is a highly contributive factor of this process as it often leads to teenage pregnancies and HIV/AIDS. One possible explanation for this behavior is that people do not have enough information about the transmission of STDs or ignore the precautions required for safe sex. Approximately 60% of new HIV infections worldwide occur in young people. The frequency of high-risk behaviors among youths may also be influenced by opportunity to engage in them, particularly the amount of time that they are unsupervised by adults. However, in diagnosing and treating these patients, we can effectively prevent the spread of HIV/AIDS. Individuals infected with STDs are 5-10 times more likely than uninfected individuals to acquire or transmit HIV through sexual contact. The breaking of the genital tract lining or skin creates a portal of entry for HIV and, hence, HIV-infected individuals with other STDs are more likely to shed HIV in their genital secretions. To date, the condom is the most effective method available for males for protection against STDs. It is important to control STDs, and prevention can be the key of this process. Prevention can be achieved through education of the population, identification of symptomatic and asymptomatic people, and effective diagnosis and treatment of these patients and their partners.

Dynamic analysis of a sexually transmitted disease model on complex networks

In this paper,a sexually transmitted disease model is proposed on complex networks,where contacts between humans are treated as a scale-free social network.There are three groups in our model,which are dangerous male,non-dangerous male,and female.By mathematical analysis,we obtain the basic reproduction number for the existence of endemic equilibrium and study the effects of various immunization schemes about different groups.Furthermore,numerical simulations are undertaken to verify more conclusions.

Epidemiological Investigation of Human Papillomavirus Infection in Men Attending a Sexually Transmitted Disease Clinic in Hangzhou Area

Objective To investigate the epidemiological characteristics of human papillomavirus （HPV） infection in men attending a sexually transmitted diseases （STD） clinic in Hangzhou area. Methods Male subjects （n=375） aged 18-70 years, attending the STD clinic were recruited. Urethral swabs were assessed for HPV DNA using polymerase chain reaction （PCR） with the consensus primers MY09/11. HPV genotypes of positive PCR products were determined by restriction fragment length polymorphisms and direct sequence analysis. Results Of the 375 swabs collected, 305 （81.3%） yielded sufficient DNA for the subsequent HPV analysis. Among the 305 subjects, the prevalence of HPV was 13.8%. Nononcogenic HPV types were found in 8.5% （26/305） of subjects, oncogenic types in 4.3% （13/305）, and multiple types in 1.0% （3/305）. The prevalence of HPV infection was higher in subjects from urban area than in those from rural area （P〈0.05）. The prevalence was also higher in those who received fewer years of education （P〈0.05） and those who had more sex partners （P〈0.05）. Conclusions HPV infection among men at high risk is not uncommon. The detection rate of HPV DNA is significantly related to some sociodemographic factors, such as residence, educational level and the number of sex partners.

Sexually Transmitted Diseases at Monkey Bay Community Hospital in Mangochi, Malawi;an Analysis of Characteristics of Common Sexually Transmitted Diseases

We present the characteristics of the commonly diagnosed sexually transmitted infections (STI) at a clinic of Monkey Bay community hospital by a retrospective study. We conducted an audit of patients’ hospital records from a STIs clinic at Monkey Bay community hospital in Mangochi District (Malawi) covering a period from January 2019 to June 2019 (18 months). Data was tabulated in excel and analyses were made based on sex, age, male circumcision status, pregnancy and the pattern of STIs diagnosed within the chosen study period. A total number of 659 clients presented at STI clinic of Monkey Bay community hospital between January 2018 and June 2019. Out these clients, 409 (62%) were females and 250 (38%) were males. Most of the patients were in the age range of 25 years or above (447, 68%). Majority of the patients were HIV negative (523, 79%). Out of the 250 males, 113 (45%) were circumcised. Among female patients 56 of the 409 (14%) were pregnant. The most common presentations for all cases put together were lower abdominal pain (253, 38%), then urethral discharge (189, 29%), abnormal vaginal discharge (141, 21%), genital ulcer disease (64, 10%), in that order. Syphilis, genital warts, inguinal bubo and scrotal swelling were less common. The most common presentation in males was urethral discharge (178, 71%), while in females it was lower abdominal pain (214, 52%). Our audit showed that in Mangochi (Malawi) sexually transmitted diseases of various types are more common among young adults, females and uncircumcised men. There was no much difference in the percentage of STI’s between HIV positive and HIV negative people. These results point to an alarmingly high level of risky sexual behaviors among sexually active age groups in this part of Malawi, a country which still has one of the highest HIV prevalence in sub-Saharan Africa. This calls for continued and better research and control for transmission of STIs in the district.

The Social Determinants of Health in Relation to Sexually Transmitted Infections in Maricopa County Arizona

Based on the information that was collected on the County Health Rankings website [1], one of the top health concerns for Maricopa County was sexually transmitted infections or STIs. A big concern with STIs is this is not a common subject explored in educational settings or addressed socially. There are many organizations, including the CDC, that have access to materials, there is limited distribution of the educational content. Therefore, the public is not well informed and lacks the information to make educated decisions. The areas with insufficiencies are knowledge of the disease processes, prevention, and treatment.

Utilization of HIV and Sexually Transmitted Infections Prevention Services, and Associated Factors among the Long-Distance Truck Drivers along the Northern Corridor Highway, Kenya

Background: Often, long-distance truck drivers’ (LDTDs’) work predisposes them to sexually transmitted infections (STIs) whose outcomes are influenced by access and behavior of seeking sexual health care. Methodology: In this study, we assessed the utilization of HIV/STI preventive services and associated factors among 296 LDTDs operating along the northern corridor highway using an interviewer-administered questionnaire for data collection at Mlolongo stopover in Machakos, Kenya. Responses for the investigated variables, including condom use, history of HIV testing, frequency of HIV testing, antiretroviral therapy (ART) use and follow-up for the HIV positive and STI treatment, were assigned a score of either 1 or 0 depending on the question’s dimension. Following summing up for each participant, we computed a weighted score ranging between 0 and 1 by dividing the summed responses by the number of eligible variables. We arbitrarily multiplied these scores by 8 to generate endpoint scores ranging from one to eight for each participant to help create a dichotomized outcome variable for utilization levels: limited utilization (1 to 4) and good utilization (5 to 8). Association between certain independent variables and the outcome variable (level of utilization of H.I.V./STIs preventive services) was analyzed using binomial logistic regression analysis in R statistical software. Results: The mean age of the LDTDs was 38.4 years, ranging from 24 - 57 years. The majority (n = 287, 97%) of the LDTDs had been tested on HIV at least once since the beginning of their career. Only 4.9% of the LDTDs had been tested on HIV within the previous three months. Of the 175 LDTDs who reported a history of STI, most (n = 173, 98.9%) of them had sought treatment. Condom use rates were higher (97.1%) among the LDTDs who had sexual interactions with casual sexual partners compared to 47.2% among regular sexual partners. Analyses classed most of the respondents (n = 231, 78.0%) as having good utilization, while the rest (22%) had limited utilization. History of STI was independently associated with utilizing HIV/STI preventive services (OR 8.4;95% CI;4.5, 16.7;P < 0.001). Conclusion: Although most of the LDTDs were classed to have good utilization of HIV/STI preventive services, the uptake of subsequent HIV testing services among them was low at only 4.9%. The association of STI history with utilization levels that we determined supports policies of integrating HIV and STI services in the delivery of sexual healthcare provision among LDTDs.

Arboviruses and Sexually Transmitted Infections in the Bioceanic Route: Health Indicators in a Municipality

Background: the physical integration of South America through a Bioceanic Corridor has been idealized for a long time by the countries that make up Mercosur. This integration will have impacts on the population residing in the cities where the route will be built. Among them, Porto Murtinho, southern Mato Grosso on the border with Paraguay, stands out, where a bridge will be built over the Paraguay River that will link these two countries. Methods: a retrospective, quantitative and cross-sectional study of a descriptive type of documentary approach that sought to analyze the prevalence of arboviruses, Sexually Transmitted Infections (STIs) and Diseases Related to Inadequate Environmental Sanitation (DRIES) notified and stored in the National System of Notifiable Diseases (SINAN). The sample consisted of new cases of these pathologies in the municipality of Porto Murtinho registered between January 2017 and December 2020. Results: there was an increase of 10% in the total number of diseases within this period. The number of dengue cases increased 36 times;the incidence of Syphilis, HIV and HPV decreased;and, finally, maintenance of cases of Gonorrhea, Leptospirosis, Yellow Fever, Zika, Chikungunya, Hepatitis A and B. Conclusions: actions are needed to prevent the increase of these pathologies together with the construction of the Bioceanic Route, thus avoiding damage population health and increased consumption of government resources.

The Educational System Against Sexually Transmitted Diseases:Optics in the Brazilian School Context

The aim of this study was to contribute to the teaching of sexually transmitted diseases(STDs)in high schools.The study was done from the research knowledge about STDs of 61 students from two schools of Rio Claro-SP,Brazil:A state and a private school,through a questionnaire(pre-test)and an interview with two biology professors,and each one from each school.The results indicated that,in general,the students in the private school had more knowledge about the subject.The public school students showed more problems with knowledge about the symptoms of STDs.In those two schools,the knowledge on the subject proved to be generic and superficial.According to the biology teachers,both of them teach about the content,and the teaching material contains themes of sexuality and STDs.From these results,an intervention was developed with students,using methods such as group dynamics and lecture dialogued lessons.After the intervention,there was an increase in the percentage of correct answers for the students of both schools(post-test)which shows that it was effective.We conclude that this work has achieved the objective of clarifying the theme to the students,but lack the schools a better dialogue with them for the planning of this content,since,although it is foreseen the your teaching,you're not going on an apprenticeship.

Knowledge of sexually transmitted infections among senior high school adolescents in the Wa Municipality of Ghana

Background:Sexually transmitted infections(STIs)are responsible for a high burden of morbidity and mortality in many developing countries especially among adolescents.Adolescents are predisposed to STIs because they are more likely to engage in unhealthy lifestyles.However,these adolescents have limited knowledge of the use and barriers to sexual and reproductive health information and care services.This study explored the knowledge of STIs among Senior High School Adolescents in the Wa Municipality of Ghana.Method:The study designed as a descriptive cross-sectional research.A multistage sampling technique was used to recruit these adolescents for the study.Totally 355 adolescents were selected from senior high schools in the Wa Municipality.Descriptive statistics and Chi-square test were used to analyze the data,at a significance level ofP<0.05.Results:The majority of respondents had good knowledge of STIs,with the most common examples of STIs identified as HIV/AIDS(80.8%,287/355)and gonorrhea(73.8%,262/355).The main known signs and symptoms identified were discharges from the penis/vagina(72.4%,257/355),painful urination(71.5%,254/355),and itching,and sores around the genital area(72.7%,258/355).The main sources of information/education of STIs for these adolescents were the school,hospital,internet and mother.Whom respondent lived with was found to be significantly associated with knowledge of STI(P<0.001).Conclusion:Many of the respondents had good knowledge of STI,and the school was the most common source of information on STL It is,therefore,important for the Ghana Education Service and the Ghana Health Service to strengthen the School Health Education Programme in second cycle institutions in the Wa Municipality.Parents,especially mothers,should be actively involved in the sexual health education of adolescents.

Treatment-seeking behaviour and barriers to service access for sexually transmitted diseases among men who have sex with men in China:a multicentre cross-sectional survey

Background:Delayed or inappropriate treatment for sexually transmitted diseases(STDs)increases the risk of HIV acquisition and may cause other harmful outcomes.However,studies on STD treatment-seeking behaviour and correlated factors in men who have sex with men(MSM)are scarce.This information is crucial for the promotion of STD treatment-seeking behaviour and reduction of HIV transmission among Chinese MSM.Methods:During 2012-2013,a multicentre cross-sectional study was conducted in 7 Chinese cities.Participants completed an interview-questionnaire and gave venous blood samples,which were then tested for antibodies to HIV,syphilis,and herpes simplex virus-2(HSV-2).MSM who tested positive for syphilis/HSV-2 or had obvious STD-related symptoms within the last 12 months were defined as suspected STD-infected MSM.Results:Of the 4496 eligible MSM who completed this survey,24.4%(1096/4496)were categorized as suspected STD-infected MSM.35.7%(391/1096)of these MSM with suspected STD infections sought STD treatment in clinics within the last 12 months.Among MSM who did not attend STD clinics for treatment,the prevalence of syphilis and HSV-2 was significantly higher;the HIV prevalence and incidence within this subpopulation reached as high as 14.5%and 12.2/100 person-years,respectively.Multivariate logistic regression analysis indicated that having 7-12 years of education(vs.≤6 years;aOR,2.5;95%CI,1.0-6.1),≥13 years of education(vs.≤6 years:aOR,2.8;95%CI,1.2-7.0),monthly income>500 USD(vs.≤500 USD:aOR,1.5;95%CI,1.1-2.1),obvious STD-related symptoms within last 12 months(aOR,5.3;95%CI,3.7-7.5),being HIV infected(aOR,1.7;95%CI,1.1-2.6),currently syphilis infected(aOR,0.6;95%CI,0.4-0.9)and HSV-2 infected(aOR,0.6;95%CI,0.5-0.9)were independent correlates with seeking STD treatment in clinics among Chinese MSM.Conclusions:The high prevalence of STD infection coupled with a low proportion of individuals who exhibit appropriate treatment-seeking behaviour create a high risk of a growing HIV epidemic among Chinese MSM.Models that prioritize better screening for and education about STDs should be urgently implemented,especially among low-income MSM.

Association of sexually transmitted infection with semen quality in men from couples with primary and secondary infertility

This study aims to compare the prevalence of sexually transmitted infections(STIs)with semen quality in men from couples with primary and secondary infertility.Semen samples were collected from 133 men who requested fertility evaluation.Seminal tract infection with Ureaplasma spp.(UU),Mycoplasma hominis(MH),Mycoplasma genitalium(MG),Chlamydia trachomatis(CT),Neisseria gonorrhoeae(NG),and herpes simplex virus-2(HSV-2)was assessed by PCR-based diagnostic assays.Among all patients,the prevalence of STIs was higher in men from couples with primary infertility than that in men from couples with secondary infertility(39.7%vs 21.7%,P=0.03).The prevalence of UU was 28.8%and 13.3%in men from couples with primary and secondary infertility,respectively.Men from couples with primary infertility were more likely to be positive for UU than men from couples with secondary infertility(P=0.04).Regarding the UU subtype,the prevalence of Ureaplasma urealyticum(Uuu)and Ureaplasma parvum(Uup;including Uup1,Uup3,Uup6,and Uup14)did not differ between the two groups.No associations between the prevalence rates of MH,MG,and CT were found in men from either infertility group.A lower sperm concentration was associated with STI pathogen positivity in men with primary infertility according to the crude model(P=0.04).The crude and adjusted models showed that semen volume(both P=0.03)and semen leukocyte count(both P=0.02)were independently associated with secondary infertility.These findings suggest the importance of classifying the type of infertility during routine diagnosis of seminal tract infections.

Health-related attitudes and risk factors for sexually transmitted infections of Chinese women who have sex with women

Background Previous studies have shown evidence of health-related risk behaviors among women who have sex with women （WSW）, such as sex with men, multiple bisexual partners, and drug use. Women who have sex with women have also been known to avoid routine physical examinations and conceal their same-sex history from physicians, which can affect their ability to receive an accurate diagnosis and treatment. No previous research has targeted women who have sex with women in China. We sought to describe women who have sex with women in China and explore risk factors for their reproductive tract infections （RTI）/sexually transmitted infections （STI）. Methods Participants were recruited through outreach in venues and online for a cross-sectional study. Data were collected using interviews and laboratory tests. Results We recruited 224 women who have sex with women. In the year preceding their participation in the study, 92% （206/224） of women reported sexual relations with women. The RTI rates were： gonorrhea （15.8%）, chlamydia （3.5%）, syphilis （0.5%）, bacterial vaginosis （14.4%）, hepatitis B virus （HBV） （0.9%）, hepatitis C virus （HCV） （0.5%）, and candidiasis （6.9%）. No HIV or herpes simplex virus （HSV） positive cases were detected. Factors associated with gonorrhea infection were non-Beijing local residency （odds ratio （OR）=2.1, 95% confidence interval （C/）： 1.2-3.8） and genital-genital contact （OR=3.1, 95% CI： 1.3-7.2）; factors associated with curable STI （excluding bacterial vaginosis, candidiasis, HBV and HCV） were non-Beijing local residency （OR=1.9; 95% CI： 1.2-3.0） and bleeding during or after sex （OR=18.1; 95% CI： 5.2-62.6）; and the factor associated with RTI （including all the infections tested） was bleeding during or after sex （OR=37.8, 95% CI： 11.2-127.4）. Conclusions Behaviors that may cause RTI/STI exist among Chinese women who have sex with women. Researchers should consider these behaviors when planninq correspondin.q prevention and interventions.

An edge-based model for non-Markovian sexually transmitted infections in coupled network

In this paper,allowing for general transmission and recovery times distributions,we proposed an edge-based age-structured-like compartmental model for STIs(EBACMS)in a coupled nctwork.We considered sexual transmissions between men with also heterosexual contacts.Mathematically,we gave the general approach of proving the nonnegativity of solutions for the system coupling ordinary and partial differen-tial equations,which can be applied to all edge-based compartment models.We then analyzed the epidemic threshold Ro with different distributions which couples the thresholds of the single-layer and bipartite networks in the percolation theory.We also studied the global stability of disease-free equilibrium with R0<1 and the final epidemic size F(the proportion of the population experiencing infection during the epidemic)with R0>1.In addition,numerical simulations indicated that given a fixed exponential transmission distribution,a higher variance(with same mean)in general recovery distribution gives smaller R0 and F.Sensitivity analysis on Ro and F in terms of the parameters illustrated that male-to-male transmission routes have a greater impact on Rg and F than the heterosexual transmission routes for the Markovian transmission process and arbitrary recovery process.The results provide a good theoretical guideline to consider the distributions of real-world STIs.

Impact of HIV/sexually transmitted infection testing on risky sexual behaviors among men who have sex with men in Langfang, China

Background Men who have sex with men （MSM） in China remain at high risk for HIV infection, the proportion of reported HIV/AIDS cases that occurred among MSM rose greatly from 2005 to 2011. HIV testing and counseling is a critical HIV prevention strategy among HIV related high-risk population, including MSM in China. This article aimed to assess the association between receiving HIV testing and high-risk sexual behaviors among MSM in Langfang, Hebei Province, China. Methods Between September and November 2007, 233 MSM were recruited to receive an HIV testing intervention. Face-to-face interviews were conducted before HIV testing and 3 months later HIV-related risk behaviors were assessed. Serological testing for HIV and other sexually transmitted infections （STIs） was performed. Results Of the recruited 233 MSM, 200 completed follow-up. Baseline prevalence was 7.8% for HIV, 21.0% for syphilis, 15.8% for gonorrhea, and 5.0% for chlamydia. Multivariate analysis indicated that inconsistent condom use （OR=7.9, 95% CI： 0.9-66.7, P=0.059） and bleeding during anal sex （OR=5.9, 95% Cl： 1.3-26.2, P=0.019） were risk factors for HIV infection, and group sex （OR=6.6, 95% Cl： 2.2-19.7, P=0.001） was a risk factor for syphilis infection at baseline. At 3 months follow-up, among STI-positive MSM, self-reported anal sex fell from 73.1% to 38.5% （P 〈0.001）; group sex fell from 19.2% to 5.8% （P 〈0.001）; and bleeding during anal sex fell from 23.1% to 5.8% （P 〈0.001）. Among STI-negative MSM, the frequency of one-night stands fell from 32.5% to 17.2% （P 〈0.001）, and oral sex rose from 57% to 78.5% （P 〈0.001）. STI-positive MSM were less likely to engage in anal sex compared to STI-negative MSM （X^2=5.189, P=0.023）. Conclusions HIV testing is an important intervention strategy among MSM. HIV testing services among MSM need to be scaled up, along with comprehensive, tailored interventions including condom promotion and STI treatment.

Incidenee and time-varying predictors of HIV and sexually transmitted infections among male sex workers in Mexico City

Background:Male sex workers are at high-risk for acquisition of sexually transmitted infections(STIs),including human immunodeficiency virus(HIV).We quantified incidence rates of STIs and identified their time-varying predictors among male sex workers in Mexico City.Methods:From January 2012 to May 2014,male sex workers recruited from the largest HIV clinic and community sites in Mexico City were tested for chlamydia,gonorrhea,syphilis,hepatitis,and HIV at baseline,6-months,and 12-months.Incide nee rates with 95%bootstrapped confide nee limits were calculated.We examined potential timevarying predictors using generalized estimating equations for a population averaged model.Results:Among 227 male sex workers,median age was 24 and baseline HIV prevalence was 32%.Incidence rates(per 100 person-years)were as follows:HIV[5.23;95%confidence interval(CI):2.15-10.31],chlamydia(5.15;95%CI:2.58-9.34),gonorrhea(3.93;95%CI:1.88-7.83),syphilis(13.04;95%CI:8.24-19.94),hepatitis B(2.11;95%CI:0.53-4.89),hepatitis C(0.95;95%CI:0.00-3.16),any STI except HIV(30.99;95%CI:21.73-40.26),and any STI including HIV(50.08;95%CI:37.6062.55).In the multivariable-adjusted model,incident STI(excluding HIV)were lower among those who reported consistently using condoms during anal and vaginal intercourse(odds ratio=0.03,95%CI:0.00-0.68)compared to those who reported inconsistently using condoms during anal and vaginal intercourse.Conclusions:Incidence of STIs is high among male sex workers in Mexico City.Consistent condom use is an important protective factor for STIs,and should be an important comp on ent of interventions to prevent incide nt infect i ons.

A risk-based model for predicting the impact of using condoms on the spread of sexually transmitted infections

We create and analyze a mathematical model to understand the impact of condom-use and sexual behavior on the prevalence and spread of Sexually Transmitted Infections(STIs).STIs remain significant public health challenges globally with a high burden of some Sexually Transmitted Diseases(STDs)in both developed and undeveloped countries.Although condom-use is known to reduce the transmission of STIs,there are a few quantitative population-based studies on the protective role of condom-use in reducing the incidence of STIs.The number of concurrent partners is correlated with their risk of being infectious by an STI such as chlamydia,gonorrhea,or syphilis.We develop a Susceptible-Infectious-Susceptible(SIS)model that stratifies the population based on the number of concurrent partners.The model captures the multi-level heterogeneous mixing through a combination of biased(preferential)and random(proportional)mixing processes between individuals with distinct risk levels,and accounts for differences in condom-use in the low-and high-risk populations.We use sensitivity analysis to assess the relative impact of high-risk people using condom as a prophylactic intervention to reduce their chance of being infectious,or infecting others.The model predicts the STI prevalence as a function of the number of partners of an individual,and quantifies how this distribution of effective partners changes as a function of condom-use.Our results show that when the mixing is random,then increasing the condom-use in the high-risk population is more effective in reducing the prevalence than when many of the partners of high-risk people have high risk.The model quantifies how the risk of being infected increases for people who have more partners,and the need for high-risk people to consistently use condoms to reduce their risk of infection.

Validation of diagnostic algorithms for syndromic management of sexually transmitted diseases

s To validate our revised syndromic algorithms of the management of sexually trans mitted diseases and determine their sensitivity, specificity, positive predictiv e value and cost effectiveness Methods Patients with either urethral discharge, vaginal discharge or genital ulcer, wer e selected during their first visits to three urban sexually transmitted disease clinics in Fujian Province, China They were managed syndromically according t o our revised flowcharts The etiology of the syndromes was detected by laborat ory testing The data were analyzed using EPI INFO V6 0 software Results A total of 736 patients were enrolled into the study In male patients with ur ethral discharge, the sensitivities for gonococcal and chlamydial infections wer e 96 7% and 100%, respectively, using the syndromic approach The total positi ve predictive value was 73% In female patients with vaginal discharge, the sen sitivity was 90 8%, specificity 46 9%, positive predictive value 50 9%, and n egative predictive value 89 3% for the diagnosis of gonorrhea and/or chlamydial infection by syndromic approach In patients with genital ulcer, the sensitivi ties were 78 3% and 75 8%, specificities of 83 6% and 42 9%, and positive pr edictive values of 60 0% and 41 0% for the diagnosis of syphilis and genital h erpes, respectively, using the syndromic approach Cost effectiveness analysi s indicated that the average cost of treatment for a patient with urethral disch arge was RMB 46 03 yuan using syndromic management, in comparison with RMB 149 19 yuan by etiological management Conclusions The syndromic management of urethral discharge was relatively effective and suit ed clinical application The specificity and positive predictive value for sy ndromic management of vaginal discharge are not satisfactory The revised flowc hart of genital ulcer syndrome could be suitable for use in clinical settings Further validation and revision are needed for syndromic approaches of vaginal d ischarge and genital ulcer

Pair formation models for sexually transmitted infections:A primer

Formodelling sexually transmitted infections,duration of partnerships can strongly influence the transmission dynamics of the infection.If partnerships are monogamous,pairs of susceptible individuals are protected from becoming infected,while pairs of infected individuals delay onward transmission of the infection as long as they persist.In addition,for curable infections re-infection froman infected partnermay occur.Furthermore,interventions based on contact tracing rely on the possibility of identifying and treating partners of infected individuals.To reflect these features in a mathematical model,pair formation models were introduced tomathematical epidemiology in the 1980's.They have since been developed into a widely used tool in modelling sexually transmitted infections and the impact of interventions.Here we give a basic introduction to the concepts of pair formation models for a susceptibleinfected-susceptible(SIS)epidemic.We review some results and applications of pair formation models mainly in the context of chlamydia infection.