bluuebunny/crossref_metadata_2025_split huggingface dataset:
O1-S07.06 Lymphogranuloma venereum in the UK: is there evidence for rectal to rectal transmission? Results of a multicenter case control study
Authors: Ward H , Macdonald N , Ronn M , Dean G , Pallawela S , Sullivan A , White J , Smith A , French P , Ison C 
Published: July 2011

BackgroundThe outbreak of lymphogranuloma venereum (LGV) in men who have sex with men (MSM) in the UK is ongoing, with over 500 cases diagnosed in 2010 alone. Control efforts have been limited by a lack of understanding of the epidemiology, particularly transmission. The majority of cases are rectal with small numbers of urogenital or pharyngeal infections. No significant reservoir of asymptomatic or undiagnosed infection has been identified. The possibility of rectal to rectal transmission is suggested by studies showing an association of LGV with fisting, use of sex toys and enemas. We aim to identify risk factors to better understand transmission.MethodsA case control study of LGV in six UK clinics from 2009 to the end of 2010. Confirmed cases of LGV in MSM were compared with symptomatic and asymptomatic controls. Clinical and behavioural data were collected using a web-based computer-assisted self-interview and linked to web-based clinical report forms (CRF). We used a two-stage process to construct multivariable logistic regression models in order to control for confounding and interaction between risk factors.ResultsWe have recruited 99 cases, 86 symptomatic and 88 asymptomatic controls. There were 94 rectal cases (including one who also had pharyngeal LGV), two urethral and one genital ulcer (two CRFs outstanding). In univariate analysis, LGV was significantly associated with many factors; the strongest associations were with HIV infection, specific anal sex practices (including unprotected receptive and insertive intercourse, rimming, use of toys, fisting, douching), meeting partners through the internet or in a backroom, and use of stimulant drugs. In final multivariable logistic regression models HIV-positivity, fisting, younger age at first clinic attendance and recent use of methamphetamine remained significant predictors of LGV when compared to asymptomatic controls. Compared to symptomatic controls, unprotected insertive anal intercourse was the only significant risk factor in the final model.ConclusionsMen reporting both insertive and receptive anal sex practices are at highest risk of LGV. Rectal to rectal transmission may be occurring with the organism being transferred via toys, fingers and penises; transient colonisation of the urethra may explain the low incidence of urethral LGV. Improved hygiene measures may have an important role in reducing transmission.
O1-S09.06 Assessing the impact of a FSW targeted HIV intervention programme on incidence and prevalence in Cotonou, Benin
Authors: Williams J , Boily M C , Lowndes C , Camden S , Demers E , Minani I , Zannou M , Anagonou S , Labbé A C , Alary M 
Published: July 2011

BackgroundFrom 1993 to 2005 female sex workers (FSW) were the focus of a HIV intervention in Cotonou where most local FSW originated from three neighbouring countries. Intervention impact was assessed using a HIV transmission model parameterised and fitted to empirical data within a Bayesian framework, to compare predicted epidemic outcomes with and without the intervention.MethodsAn age-structured model was developed of HIV transmission in Cotonou, coupled with a non-age structured Gc model. The model included realistic demography, heterogeneous sexual risk groups including local and migrant FSW to and from Cotonou, clients and general population (GP); each FSW nationality was parameterised separately. Programs of condom use and STI treatment modelled reflected levels of uptake pre- and post-intervention. Plausible parameter ranges based on local multiple survey data from different risk groups and time points and literature reviews (ie, prior parameter distribution) were sampled repeatedly by Latin hypercube sampling. Model predictions from parameter sets matching (ie, fitting") observed HIV prevalence data from Cotonou (FSW by nationality, their clients, and broad GP age-bands) at different time points were accepted as good fits (ie, posterior parameter distribution (PPD)) and used to estimate impact (95% credibility interval (CrI)) by comparing HIV incidence predicted based on the PPD with that using the same parameter values except for the assumption that condom use and STI treatment remained at 1993 levels (control group/counterfactual).ResultsFrom 100 000 parameter combinations tested, 18 produced results that agreed with observed HIV prevalences in FSW (Abstract O1-S09.06 figure 1) and other groups over time. Results with no intervention suggest a peak HIV prevalence in FSW 10–12 years later than observed and at around 75%, compared with the observed level of just over 53% (corresponding GP prevalences were 9.6% & 6.7% respectively). Results also suggest that about 33%(CrI: 28, 37) and 25%(CrI: 17, 33) potential HIV cases may have been averted in Cotonou FSW and GP respectively, by increased condom use and STI services after the start of the intervention.Abstract O1-S09.06 Figure 1ConclusionsCoupled with observed HIV trends, the analysis indicates that FSW targeted intervention was effective in curtailing the HIV epidemic in Cotonou-based FSW despite high turnover of foreign FSW. There was also substantial impact in the general population by impeding onward transmission to clients/boy-friends.
O1-S10.03 Lymphogranuloma venereum, HIV and high-risk behaviour: findings from LGV enhanced surveillance and mathematical modelling
Authors: Ronn M , Garnett G , Hughes G , Ison C , Simms I , Alexander S , Ward H 
Published: July 2011

BackgroundLymphogranuloma venereum (LGV) re-emerged in industrialised countries in the early 2000s and most transmission is assumed to occur among high-risk HIV-positive men who have sex with men (MSM). As the epidemic matures, we would expect to see declining HIV prevalence among cases as the transmission moves outside the initial core groups, however LGV cases continue to present with high levels of HIV-positivity. We have previously conducted a systematic review and a meta-analysis of literature published on LGV and found an eightfold greater likelihood of HIV-positivity among LGV cases when compared to controls with non-LGV chlamydia. In this study we investigate the role of high-risk behaviour, serosorting and differences in transmission probability as contributing factors to the persistent association between HIV and LGV.MethodsData from LGV Enhanced Surveillance in the UK were used to investigate the relationship between HIV-positivity and LGV acquisition by setting HIV-positivity as the outcome in logistic regression. A simple deterministic compartmental model was developed, stratified by HIV-status and risk behaviour, to simulate the spread of infection among MSM in a large metropolitan population. Assortative mixing for HIV status and high-risk behaviour were controlled independently of each other see Abstract O1-S10.03 figure 1.Abstract O1-S10.03 Figure 1Flowchart illustrating the model structure.ResultsUp to date approximately 81% of the 1500 confirmed LGV cases have had surveillance forms returned with above 70% HIV-prevalence among cases over time. HIV-positive LGV cases were more likely to report unprotected anal intercourse and greater number of partners than HIV-negative LGV cases in surveillance data. The mathematical model indicates that extreme levels of serosorting would be needed to explain the high prevalence of HIV in the presence of high-risk HIV-negative group. Increase in the number of HIV-positive individuals, higher transmission probability in HIV-positive and serosorting together were better able to reproduce the strong association between HIV and LGV.ConclusionsDifferential acquisition of LGV occurs according to HIV status. LGV acquisition among HIV-positives may be due to serosorting together with an increased transmission probability due to reduced condom use and sexual practices, and potential biological susceptibility. Findings suggest that HIV-positive MSM need targeted health promotion in view of their different risk behaviours.
O1-S01.06 Estimation of the burden of disease and costs of genitalChlamydia trachomatisinfection in Canada
Authors: Tuite A , Fisman D 
Published: July 2011

BackgroundChlamydia trachomatis(CT) is the most common notifiable infectious disease in Canada. Rates of infection have been increasing since the mid-1990s, suggesting that alternate control strategies may be required. Given that the current cost of Chlamydia infections in Canada is unknown, we sought to estimate the burden of CT in the Canadian population, to provide a foundation on which health economic analyses of competing Chlamydia control strategies can be constructed.MethodsWe used an age- and sex-structured mathematical model parameterised to reproduce trends in CT prevalence in the Canadian population aged 10 to 39 years. Model parameters were derived from epidemiologic studies and by model calibration. We incorporated data on changing test patterns of asymptomatically infected individuals over time. Costs were identified, measured, and valued using a modified societal perspective and were converted to 2009 Canadian dollars. The main outcome measures were the current net cost and burden of illness attributable to CT infection.ResultsThe model reproduced trends in CT prevalence observed for the time period between 1991 and 2008. Under base case model assumptions, there appeared to be a trend of increasing detection of CT cases (due to increases in screening and subsequent detection of asymptomatic cases), despite an underlying decrease in actual CT infections in the population. The total estimated costs associated with CT infection over this time period were over $1.0 billion, or $56.4 million per year. The costs of screening and treatment of asymptomatic infections as a proportion of total CT costs were estimated to have increased over time, while the costs of long-term sequelae associated with untreated infections declined the same period.ConclusionsDespite increases in screening over time, the total economic burden associated with CT in Canada remains high; however, the projections of our model suggest that these increases in screening and the subsequent detection of asymptomatic infections may be reducing the costs associated with the treatment downstream sequelae of untreated infections. Further investigation of trends in chlamydia-associated complications is required to better understand the impact of screening on CT incidence in Canada.
O1-S10.06 HIV/STI prevalence among men who have sex with men in 4 cities, China and associated risk factors for HIV infection
Authors: Chen X , Jiang N , Wang B 
Published: July 2011

ObjectivesThe data on STIs control and HIV prevention is limited among MSM population. To examine STIs control strategies for HIV prevention in a community-based cohort of HIV-negative MSM, community intervention trail was conducted between 2009 and 2011. This report mainly discussed baseline survey results.MethodsThis study was conducted in MSM community of four mid-sized cities from Jul. to Sep. 2009. All participants were recruited through venue-based recruitment, complemented by peer referral using snowball method, Questionnaire were completed in STD clinics or VCT centers. Blood samples were collected for HIV, syphilis and HSV-2 tests, and urine sample for CT/NG PCR tests.Results35.3% participants self-identified as homosexual and 44.7% bisexual. The most popular way to seek male sexual partners was internet (38.4%). 15.9% of participants had provided or acquired sex services with male, while 19.1% of respondents reported unprotected anal intercourse (UAI) in the last sex services. 3.8% of participants had experienced sadism & masochism(SM). In past 6 months, 80.8% of participants had anal sex with man and 29.0% reported UAI during the last intercourse. 38.5% of participants reported having had sex with woman and only 45.2% of those reported using condom during the last intercourse with woman. 18.0% of participants involved in commercial sex services had taken drugs such as methamphetamine, Ketamine and MDMA.10.6% of participants was HIV infection. 34.4% of participants is TP-ELISA positive results indicated a history of syphilis infection, and 20.9% were both positive results of ELISA and TRUST indicated active syphilis. 3.0% of participants were tested as NG infection, 6.8% was CT infected, and 16.2% were HSV-2 infected. Significant factors associated with HIV infection were self-reported STD infection history [AOR=2.1, 95% CI: 1.29% to 4.26%], syphilis infection [AOR=2.70, 95% CI: 1.81% to 4.04%], and HSV-2 infection [AOR=3.07, 95% CI: 2.09% to 4.50%].ConclusionsMSM have been potential bridge-population for HIV/STIs from most-at-risk population to general population. Intervention activities should target the internet, sexual social networks, and certain subpopulations such as those taking drugs in commercial sex services or infected with STIs. Friendly and high-quality STIs service should reach to MSM who do not attend STD clinics. Campaigns are urgent not only to boost individual condom use but also to create culture for condom use in MSM community.
O1-S11.01 Time evolution of the fraction of new HIV infections due to primary infection among high risk groups in southern India
Authors: Pickles M , Boily M C , Vickerman P , Ramesh B M , Washington R , Deering K , Verma S , Blanchard J , Moses S , Alary M 
Published: July 2011

BackgroundHIV infectivity is considerably higher during primary infection (PI: first few months after infection). PI is believed to be an important biological driver of HIV transmission at the population level, which has implication for prevention. We aimed to estimate the contribution of PI to HIV spread among high-risk groups in southern India.MethodsWe used incidence predictions from a bespoke dynamical model of HIV transmission among FSW/clients parameterised and fitted to district-specific behavioural data and HIV/STI prevalence estimates, within a Bayesian framework. Multiple rounds of cross-sectional survey data from among FSW/clients of Mysore and Belgaum, carried out as part of the evaluation of Avahan, the India AIDS initiative, were used to inform plausible parameter ranges and estimate HIV prevalence. Assumed risk of HIV infection (RRHIV/PI) during PI was elevated by 4.5- to 19-fold compared to asymptomatic infections (based on systematic review) and lasted for 3 to 6 months. The annual fraction of new HIV infections (AF) due to primary infection was estimated over time from the 196 and 796 posterior parameter sets fitting Mysore and Belgaum data, respectively.ResultsThe median AF (overall: clients+FSW) declined from 57.3% (min=34, max=82)% in 1987 (assumed start of epidemic) to 49% (29,70)% in 2000, 43.7% (25,65)% in 2004, 23.8%/24.3% (10/10, 42/43)% in 2010/2025 for Mysore (Abstract O1-S11.01 figure 1). Similar AF estimates were obtained in Belgaum and for FSWs and clients separately in both districts. The univariate association between AF and RRHIV/PI declined slightly over time (Abstract O1-S11.01 figure 1). In multivariate regression analysis, RRHIV/PI (slope=0.027), duration of the whole infectiousness period (slope=−0.014) and duration of primary infection (slope=0.587) were significantly associated with AF early in the epidemic (1988) (R2=0.833, p value<0.001). However, the AF in 2025 was also associated with number of years selling sex by street-based FSW (slope=−0.020, p value=0.042) and number of years buying sex by high-activity clients (slope=−0.004, p value=0.055) (R2=0.684).Abstract O1-S11.01 Figure 1FSW and clients combined Mysore.ConclusionsThe role of primary infection decreased as the HIV epidemic matured but could still account for a large fraction of new infections, especially if RRHIV/PI is above 10. Early on, its contribution depended on parameters of primary infections. Later on, its contribution also depended on the renewal of high-risk susceptible population, which fuels HIV incidence.
O1-S11.03 How many infections are averted by behaviour change after early HIV diagnosis & counselling of MSM? Estimates from a stochastic individual-based model
Authors: White P , Fox J , MacDonald N , Weber J , McClure M , Fidler S , Ward H 
Published: July 2011

BackgroundA recent paper (Fox et al HIV Medicine 2009) reported that MSM in the UK significantly reduced their transmission-risk behaviour following HIV diagnosis and suggested that this could be effective in averting transmission during the highly-infectious primary infection stage. However, cost-effectiveness analysis is required to inform policy-making. To assess the effectiveness of early HIV diagnosis in MSM as a prevention strategy we quantified its potential impact in terms of transmission HIV events averted.MethodsWe developed an individual-based stochastic transmission model to calculate the number of HIV-transmission events expected to occur from a cohort of recently-diagnosed MSM with and without the changes in behaviour that occurred post-diagnosis and counselling. The model incorporates different types of sex-act, patterns of condom use, and distinguishes between regular and casual partners.ResultsIn the 12 weeks post-diagnosis, for a large majority of respondents there was a reduction in the expected number of casual partners who would be infected: 76% of participants eliminated risk of onward transmission entirely. However, a small proportion still presented a transmission risk. Overall, reductions in HIV transmission risk behaviour post-diagnosis would have reduced estimated secondary transmission during primary HIV infection (PHI) from been 33 (23–37) to 12 (6–14)—a reduction of 62% (32%–83%). Diagnosis after PHI produces a more modest reduction in transmission by missing the high-infectivity period.ConclusionsDiagnosis of PHI can produce a large proportionate reduction in HIV-transmission events by reducing transmission-risk behaviour. Due to the high infectivity but short duration of primary infection, even short-term behaviour change can significantly reduce transmission. Later diagnosis is less effective, whilst early diagnosis requires frequent or highly-targeted testing. Whilst further work is required to determine the costs of different testing strategies, our quantification of the number of infections averted is an essential component of an assessment of the cost-effectiveness of strategies to increase early diagnoses of HIV infection.
O1-S11.04 Targeting the use of HIV RNA screening to maximise yield and minimise cost: NYC Health Department STD Clinics, 2008–2010
Authors: Blank S , Borges C , Kowalski A , Sebiyam S , Sweeney M 
Published: July 2011

BackgroundNucleic acid amplification testing (NAAT) is an important tool for identifying acute HIV infection (AHI), a period of high infectivity when antibody is undetectable. NAAT pooling methods (pNAAT) help contain the costs of screening for AHI. In 2008 NYC STD clinics began routine pNAAT screening for all rapid antibody negative specimens; it was standard of care in all nine clinics by 2009. A pattern of risk factors among AHI cases detected during universal screening suggested the feasibility of using targeted screening to maximise the yield of AHI cases detected while minimising costs of screening.MethodsUsing medical record data, we reviewed cases of AHI diagnosed in nine NYC STD clinics for 2008–2009. From these we developed targeting criteria for AHI screening, and compared yields and costs before and after targeting.was implemented.ResultsTargeted screening began in May 2010 and included the following risk criteria: MSM, females who have had sex with MSM, sex with an injection drug user, exchange sex for money or drugs, shared injection drug works, or recent victim of sexual assault. Prior, 42 696 specimens were screened by pNAAT from June through December 2009, yielding 23 AHI cases (5.4 cases/10 000 specimens). Of these cases, there were 21 males, including 15 who have sex with men (MSM) (71%, 15/21), 1 female, and 1 transgender. The mean age for patients was 30 years; racial/ethnic breakdown was: 57% Black, 39% Hispanic, 13% white, 4% other. Subsequently, 5280 specimens were screened by pNAAT from June through December 2010, representing an 88% decrease in testing compared to the same period during the previous year. A total of 18 AHI cases (34.1/10 000 specimens) were detected; all were MSM. The mean age was 29 years and racial/ethnic breakdown was: 44% Black, 28% Hispanic, 28% white, 5% Asian. Cost data are provided in Abstract O1-S11.04 table 1.Abstract O1-S11.04 Table 1Cost effectiveness of targeted AHI screeningUniversalTargetedAverage pooled AHI specimens per month5700770Annual cost of pooled AHI screening$650 000$91 296Annual yield3335Average total cost per month$54 167$7608Average cost per AHI case identified$19 697$2608ConclusionAHI screening increases case detection compared to using antibody tests alone. After initial investment in the effort, we were able to cut the cost per case identified by over sevenfold. This approach may make AHI screening more feasible/affordable in settings with patients at very high risk of newly-acquiring HIV.
O1-S11.06 Burden of genital discharge pathogens and associated characteristics of asymptomatic HIV-infected patients in Johannesburg, South Africa
Authors: Lewis D , Chirwa T , Msimang V , Radebe F , Kamb M , Sanne I , Firnhaber C 
Published: July 2011

BackgroundThe prevalence of asymptomatic STIs and urethritis/cervicitis pathogen-associated patient characteristics were determined among patients attending a HIV treatment centre in Johannesburg.MethodsConsenting consecutive HIV-infected patients, asymptomatic for symptoms/signs of genital discharge, were screened over 12 months for gonorrhoea, trichomoniasis, chlamydial andMycoplasma genitaliuminfections using a real-time PCR assay. Bacterial vaginosis (BV) and Candida were detected by microscopy (women only). Serological assays diagnosed syphilis (RPR/TPPA) and herpes simplex type 2 (IgG ELISA) infections. Patients returned at 2 weeks; those with positive results were treated and given contact slips for partners. If available, patients' most recent CD4 (83%) and viral load (VL) (60%) results were recorded. Demographic, clinical and behavioural data were collected by nurse-administered questionnaire. A descriptive analysis was conducted to obtain frequency distributions of patient and STI prevalence data. Associations were investigated using the χ2test at a 5% level of significance. A multiple logistic regression model was fitted to find factors associated with urethritis/cervicitis pathogens.Results1109 patients were enrolled (551 men, 558 women). Compared with men, women were younger with a mean age [SD] of 35.0 [7.3] vs 37.9 [7.9] years (p<0.001), reported more STIs in the past year (65.5% vs 56.5%, p=0.002), were less likely to know their partner's HIV status (53.1% vs 62.3%, p=0.007), were more likely to be on HAART (70.4% vs 59.7%, p<0.001) with an undetectable VL (81.0% vs 69.9%, p<0.001) and a higher mean [SD] CD4 count of 346 [203] vs 232 [173] cells/mm3 (p<0.001). Urethritis/cervicitis pathogens were detected in 119/558 (21.3%) women and 90/550 (16.4%) men (p=0.035). BV and Candida were detected in 155 (28.0%) and 101 (18.3%) women, respectively. Detection of urethritis/cervicitis pathogens was associated with recent sexual intercourse with a regular partner (adjusted OR, aOR 1.64, 95% CI 1.08% to 2.48%). Trichomoniasis was associated with female gender (aOR 2.45, 95% CI 1.39% to 4.32%) and sub-optimal condom use with regular partners (aOR 2.04, 95% CI 1.23% to 3.41%).ConclusionsUrethritis/cervicitis pathogens were highly prevalent among this asymptomatic population. The benefit of introducing such STI screening programmes to improve reproductive health and HIV prevention efforts requires further study.