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1.
In this work, we estimate the proportions of transmissions occurring in main vs. casual partnerships, and by the sexual role, infection stage, and testing and treatment history of the infected partner, for men who have sex with men (MSM) in the US and Peru. We use dynamic, stochastic models based in exponential random graph models (ERGMs), obtaining inputs from multiple large-scale MSM surveys. Parallel main partnership and casual sexual networks are simulated. Each man is characterized by age, race, circumcision status, sexual role behavior, and propensity for unprotected anal intercourse (UAI); his history is modeled from entry into the adult population, with potential transitions including HIV infection, detection, treatment, AIDS diagnosis, and death. We implemented two model variants differing in assumptions about acute infectiousness, and assessed sensitivity to other key inputs. Our two models suggested that only 4–5% (Model 1) or 22–29% (Model 2) of HIV transmission results from contacts with acute-stage partners; the plurality (80–81% and 49%, respectively) stem from chronic-stage partners and the remainder (14–16% and 27–35%, respectively) from AIDS-stage partners. Similar proportions of infections stem from partners whose infection is undiagnosed (24–31%), diagnosed but untreated (36–46%), and currently being treated (30–36%). Roughly one-third of infections (32–39%) occur within main partnerships. Results by country were qualitatively similar, despite key behavioral differences; one exception was that transmission from the receptive to insertive partner appears more important in Peru (34%) than the US (21%). The broad balance in transmission contexts suggests that education about risk, careful assessment, pre-exposure prophylaxis, more frequent testing, earlier treatment, and risk-reduction, disclosure, and adherence counseling may all contribute substantially to reducing the HIV incidence among MSM in the US and Peru.  相似文献   

2.

Background

Anal human papillomavirus (HPV) infection and its related diseases are relatively common in men who have sex with men (MSM), especially in those HIV positive. In China, molecular epidemiology of anal HPV infection among HIV-positive MSM has been sparsely studied.

Methods

A cross-sectional study was conducted among HIV-positive MSM in Xi’an, China between April and July 2014. Anal swabs were collected for HPV genotyping.

Results

A total of 195 HIV-positive MSM were included in this study. HPV genotyping showed that 99.0% (191/193) of participants were positive for at least one of the targeted 37 HPV genotypes. 183 (94.8%) of them were infected with multiple high-risk types and 154 (79.8%) of them with low-risk HPV types. HPV 18 was the most frequently identified high-risk type, followed by HPV 16 and HPV 51. As for low-risk types, HPV11, HPV 6 and HPV 81 were most commonly observe. High-risk HPV infection was found to be associated with the status of antiretroviral therapy (ART), the distribution of low-risk types was observed to be varied by CD4+ T cell level.

Conclusion

Almost all HIV-positive MSM were anal HPV infected in our study. It is highly recommended to consider regular active screening and preventive intervention of HPV infection among this high risk population.  相似文献   

3.

Background

Three trials have demonstrated the prophylactic effect of male circumcision (MC) for HIV acquisition among heterosexuals, and MC interventions are underway throughout sub-Saharan Africa. Similar efforts for men who have sex with men (MSM) are stymied by the potential for circumcised MSM to acquire HIV easily through receptive sex and transmit easily through insertive sex. Existing work suggests that MC for MSM should reach its maximum potential in settings where sexual role segregation is historically high and relatively stable across the lifecourse; HIV incidence among MSM is high; reported willingness for prophylactic circumcision is high; and pre-existing circumcision rates are low. We aim to identify the likely public health impact that MC interventions among MSM would have in one setting that fulfills these conditions—Peru—as a theoretical upper bound for their effectiveness among MSM generally.

Methods and Findings

We use a dynamic, stochastic sexual network model based in exponential-family random graph modeling and parameterized from multiple behavioral surveys of Peruvian MSM. We consider three enrollment criteria (insertive during 100%, >80% or >60% of UAI) and two levels of uptake (25% and 50% of eligible men); we explore sexual role proportions from two studies and different frequencies of switching among role categories. Each scenario is simulated 10 times. We estimate that efficiency could reach one case averted per 6 circumcisions. However, the population-level impact of an optimistic MSM-MC intervention in this setting would likely be at most ∼5–10% incidence and prevalence reductions over 25 years.

Conclusions

Roll-out of MC for MSM in Peru would not result in a substantial reduction in new HIV infections, despite characteristics in this population that could maximize such effects. Additional studies are needed to confirm these results for other MSM populations, and providers may consider the individual health benefits of offering MC to their MSM patients.  相似文献   

4.

Objectives

To assess HIV incidence and its associated risk factors among young men who have sex with men (YMSM) in urban areas, China.

Design

The study used a prospective cohort study design and standard diagnostic tests.

Methods

A twelve-month prospective cohort study was conducted among YMSM (18–25 years old) in 8 large cities in China. The participants were recruited via snowball sampling. A total of 1102 HIV-negative YMSM completed baseline assessment, 878 YMSM participants completed 6-month follow-up, and 902 completed 12-month follow-up. HIV was screened by an enzyme-linked immunosorbent assay and confirmed with Western Blot. Syphilis was screened via rapid plasma reagent and confirmed by treponema pallidum particle agglutination assay.

Results

78 HIV seroconversions were identified within 1168.4 person-year observations yielding an incidence rate of 6.7 per 100 person-years. HIV seroconversion was associated with non-student status (RR = 2.61, 90% CI = 1.3–5.26), low HIV transmission knowledge (RR = 8.87, 90% CI = 2.16–36.43), and syphilis infection (RR = 5.04, 90% CI = 2.57–9.90).

Conclusions

Incidence of HIV among YMSM is high in urban areas of China. Interventions measures are required to contain the HIV epidemic within this population.  相似文献   

5.
6.

Background

Men who have sex with men (MSM) bear a disproportionately higher burden of HIV infection than the general population. MSM in the Middle East and North Africa (MENA) are a largely hidden population because of a prevailing stigma towards this type of sexual behavior, thereby limiting the ability to assess infection transmission patterns among them. It is widely perceived that data are virtually nonexistent on MSM and HIV in this region. The objective of this review was to delineate, for the first time, the evidence on the epidemiology of HIV among MSM in MENA.

Methods and Findings

This was a systematic review of all biological, behavioral, and other related data on HIV and MSM in MENA. Sources of data included PubMed (Medline), international organizations'' reports and databases, country-level reports and databases including governmental and nongovernmental organization publications, and various other institutional documents. This review showed that onsiderable data are available on MSM and HIV in MENA. While HIV prevalence continues at low levels among different MSM groups, HIV epidemics appear to be emerging in at least few countries, with a prevalence reaching up to 28% among certain MSM groups. By 2008, the contribution of MSM transmission to the total HIV notified cases increased and exceeded 25% in several countries. The high levels of risk behavior (4–14 partners on average in the last six months among different MSM populations) and of biomarkers of risks (such as herpes simplex virus type 2 at 3%–54%), the overall low rate of consistent condom use (generally below 25%), the relative frequency of male sex work (20%–76%), and the substantial overlap with heterosexual risk behavior and injecting drug use suggest potential for further spread.

Conclusions

This systematic review and data synthesis indicate that HIV epidemics appear to be emerging among MSM in at least a few MENA countries and could already be in a concentrated state among several MSM groups. There is an urgent need to expand HIV surveillance and access to HIV testing, prevention, and treatment services in a rapidly narrowing window of opportunity to prevent the worst of HIV transmission among MSM in the Middle East and North Africa. Please see later in the article for the Editors'' Summary  相似文献   

7.

Background

Among Latin America’s concentrated HIV epidemics, little is known about men who have sex with men (MSM) in Colombia, the region’s third largest country. To date, surveillance studies have been limited to Bogota, while 80% of HIV cases and deaths originate from Colombia’s other cities and departments. The extent to which interventions should prioritize MSM outside of Bogota is unknown.

Methods

We recruited 2603 MSM using respondent-driven sampling from seven of Colombia’s largest cities. HIV prevalence was estimated by site from dried blood spot samples. Behavioral data were collected through face-to-face interviews and risk factors for HIV infection analyzed using weighted, multi-level logistical regression models accounting for recruitment patterns.

Results

Across cities, HIV prevalence averaged 15%, varied from 6% to 24% and was highest in Cali, Bogota, and Barranquilla. In the past 12 months, 65% of MSM had ≥ 5 casual male partners and 23% had a female partner. Across partnerships (i.e., casual, stable, and commercial), the proportion of MSM engaging in unprotected sex was ≥ 52% with male partners and ≥ 66% with female partners. Self-reported history of STI (24%) and past-year illicit drug use (38%) were also common. In multivariate analysis, age ≥ 35 (adjusted odds ratio [AOR], 19.2) and 25–39 (AOR, 5.6) relative to ≤ 18–24 years, identifying as homosexual relative to heterosexual (AOR 0.1), meeting casual partners on the Internet (adjusted odds ratio [AOR], 3.1) and age of sexual debut of ≤ 13 years (AOR, 3.1) predicted HIV infection. HIV testing and prevention messaging reached just 24% of MSM in the past year.

Conclusions

Findings support consistently elevated HIV burden among MSM throughout Colombia’s largest cities and a need for enhanced behavioral prevention and HIV testing, emphasizing men who use the Internet as well as physical venues to meet sex partners.  相似文献   

8.
Black men who have sex with men (BMSM) experience among the highest rates of HIV infection in the United States. We conducted a community-based ethnography in New York City to identify the structural and environmental factors that influence BMSMs vulnerability to HIV and their engagement with HIV prevention services. Methods included participant observation at community-based organizations (CBOs) in New York City, in-depth interviews with 31 BMSM, and 17 key informant interviews. Our conceptual framework shows how creating and sustaining safe spaces could be a critical environmental approach to reduce vulnerability to HIV among BMSM. Participant observation, in-depth and key informant interviews revealed that fear and mistrust characterized men’s relation to social and public institutions, such as churches, schools, and the police. This fear and mistrust created HIV vulnerability among the BMSM in our sample by challenging engagement with services. Our findings suggest that to be successful, HIV prevention efforts must address these structural and environmental vulnerabilities. Among the CBOs that we studied, “safe spaces” emerged as an important tool for addressing these environmental vulnerabilities. CBOs used safe spaces to provide social support, to address stigma, to prepare men for the workforce, and to foster a sense of community among BMSM. In addition, safe spaces were used for HIV and STI testing and treatment campaigns. Our ethnographic findings suggest that safe spaces represent a promising but so far under-utilized part of HIV prevention infrastructure. Safe spaces seem integral to high impact comprehensive HIV prevention efforts, and may be considered more appropriately as part of HIV capacity-building rather than being nested within program-specific funding structures.  相似文献   

9.

Background

The preventive effects of antiretroviral treatment (ART) on onward transmission of HIV are a major reason for broadening eligibility for ART. In the WHO European Region, surveillance reveals substantial differences in access to ART across regions and sub-populations. We analysed self-reported data on ART and reasons for not taking ART from EMIS, a large Pan-European Internet survey among men-who-have-sex-with-men (MSM).

Methods

Respondents from 38 European countries reported their last HIV test result and, if diagnosed with HIV, their treatment status, and reasons for not taking or having stopped ART from a 7 item multiple choice list and/ or answered an open-ended question to give other reasons. Responses were classified as fear of consequences, perceived lack of need, and ART inaccessibility based on factor analysis. Associations between not taking ART because of fear of consequences, and demographic, behavioural and contextual indicators were identified in a multivariable regression model.

Results

13,353 (7.7%) of 174,209 respondents had been diagnosed with HIV. Among them 3,391 (25.4%) had never received ART, and 278 (2.1%) had stopped taking ART. Perceived lack of need was by far the most common reason for not taking or stopping ART (mentioned by 3259 (88.8%) respondents), followed by fear of consequences (428 (11.7%)), and ART inaccessibility (86 (2.3%)). For all reasons, an East-West gradient could be seen, with larger proportions of men living in Central and Eastern Europe reporting reasons other than medical advice for not taking ART. A minority of men were reluctant to start ART independent of medical advice and this was associated with experiences of discrimination in health care systems.

Conclusions

ART is widely available for MSM diagnosed with HIV across Europe. Not being on treatment is predominantly due to treatment not being recommended by their physician and/or not perceived to be needed by the respondent.  相似文献   

10.
In 2011, 62% of estimated new HIV diagnoses in the United States were attributed to male-to-male sexual contact (men who have sex with men, MSM); 39% of these MSM were black or African American. HIV testing, recommended at least annually by CDC for sexually active MSM, is an essential first step in HIV care and treatment for HIV-positive individuals. A variety of HIV testing initiatives, designed to reach populations disproportionately affected by HIV, have been developed at both national and local levels. We assessed changes in HIV testing behavior among MSM participating in the National HIV Behavioral Surveillance System in 2008 and 2011. We compared the percentages tested in the previous 12 months in 2008 and 2011, overall and by race/ethnicity and age group. In unadjusted analyses, recent HIV testing increased from 63% in 2008 to 67% in 2011 overall (P<0.001), from 63% to 71% among black MSM (P<0.001), and from 63% to 75% among MSM of other/multiple races (P<0.001); testing did not increase significantly for white or Hispanic/Latino MSM. Multivariable model results indicated an overall increase in recent HIV testing (adjusted prevalence ratio [aPR] = 1.07, P<0.001). Increases were largest for black MSM (aPR = 1.12, P<0.001) and MSM of other/multiple races (aPR = 1.20, P<0.001). Among MSM aged 18–19 years, recent HIV testing was shown to increase significantly among black MSM (aPR = 1.20, P = 0.007), but not among MSM of other racial/ethnic groups. Increases in recent HIV testing among populations most affected by HIV are encouraging, but despite these increases, improved testing coverage is needed to meet CDC recommendations.  相似文献   

11.

Background

Despite the high HIV prevalence among men who have sex with men (MSM) in sub-Saharan Africa, little is known about their access to HIV services. This study assessed barriers and opportunities for expanding access to HIV services among MSM in Uganda.

Methods

In October-December 2013, a cross-sectional qualitative study was conducted in 12 districts of Uganda. Semi-structured in-depth interviews were conducted with 85 self-identified MSM by snowball sampling and 61 key informants including HIV service providers and policy makers. Data were analysed using manifest content analysis and Atlas.ti software.

Results

Three quarters of the MSM (n = 62, 72.9%) were not comfortable disclosing their sexual orientation to providers and 69 (81.1%) felt providers did not respect MSM. Half (n = 44, 51.8%) experienced difficulties in accessing health services. Nine major barriers to access were identified, including: (i) unwelcoming provider behaviours; (ii) limited provider skills and knowledge; (iii) negative community perceptions towards MSM; (iv) fear of being exposed as MSM; (v) limited access to MSM-specific services; (vi) high mobility of MSM, (vii) lack of guidelines on MSM health services; viii) a harsh legal environment; and ix) HIV related stigma. Two-thirds (n = 56, 66%) participated in MSM social networks and 86% of these (48) received support from the networks to overcome barriers to accessing services.

Conclusions

Negative perceptions among providers and the community present barriers to service access among MSM. Guidelines, provider skills building and use of social networks for mobilization and service delivery could expand access to HIV services among MSM in Uganda.  相似文献   

12.
Sex Expression in Flowering   总被引:1,自引:0,他引:1  
Sex expression constitutes a specific aspectof the physiology of flowering and provides agood subject for the study of differentiation.Although most plants are hermaphroditic, quitea number of them are monoecious or dioecious,in which one is faced with the specific problemof sex expression beyond the general problem offlowering. Our earlier work on this subject can be tra-ced back to 1957 (Tsao et al. 1957).Earlier work on potted plants In pot experiments, we have studied the  相似文献   

13.

Objective

While the HIV epidemic varies greatly by region and population group throughout China, the HIV incidence among men who have sex with men (MSM) continues to rise at an alarmingly fast pace. We seek to analyze the risk factors associated with HIV infection among MSM recruited from different channels in large urban centers across China, in an attempt to shed light on the design of future targeted intervention strategies.

Methods

A total of 33,684 MSM from 14 cities and one province were recruited from July to December 2011. Demographic (e.g. age, marital status, education) and behavioral (e.g. condom use, HIV testing history) data were collected using information collection cards. Blood samples were also collected to test for HIV and Syphilis.

Results

Participants were recruited from five different channels, and all demonstrated distinct characteristics. The overall rate of positive HIV screening was 6.27% and the rate of syphilis infection was 6.50%. Participants recruited from bathhouses had the highest HIV (11.80%) and syphilis infection rates (11.20%). Participants who were infected with syphilis had the highest HIV-positive screening rate (13.75%; 95% CI OR, 2.33-3.06). living in the southwest region of the country (11.64%; OR=2.76, 95%CI OR 2.19-3.47), Being >20 years of age (P<0.001), living in the southwest region of the country (OR=2.76, 95%CI 2.19-3.47), not having sex with female over the previous 3 months (OR=1.27, 95%CI 1.09-1.48), no condom use during the last anal intercourse (OR=1.54, 95%CI 1.39-1.70) and other factors were all associated with a higher probability of having an HIV-positive test result.

Conclusion

Depending on the way they are recruited, more targeted interventions are required to prevent the spread of HIV/AIDS among MSM with different characteristics and behaviors. Results from this study could provide evidence for researchers to conduct further studies and policy-makers to establish more effective and strategic interventions for MSM in China.  相似文献   

14.

Background

Although increased prevalence of transfusion transmissible infections (TTI) among “men who have sex with men” (MSM) has been well documented, the exclusion of MSM as blood donors is contested. The aim of this systematic review is to find studies that describe the risk of TTI in MSM blood donors.

Methods

We searched MEDLINE, Embase, The Cochrane Central Register of Controlled Trials, Cinahl, and Web of Science, and used GRADE for determining evidence quality. We included studies comparing MSM and non-MSM blood donors (or people eligible to give blood), living in areas most relevant for our Blood Service.

Results

Out of 18 987 articles, 14 observational studies were included. Two studies directly compared MSM with non-MSM donors showing that MSM donors have a statistically significant higher risk of HIV-1 infections. In one of these studies it was shown that this was related to recent (< 12 months) MSM contact. In two additional studies no evidence was shown in favour of a certain deferral period for MSM. Ten studies, applying permanent deferral for MSM, compared infected versus non-infected donors. One study found that MSM is a statistically significant risk factor for HIV-1 infection in blood donors. For other TTI such as HBV or HCV, an increased risk of infection could not be demonstrated, because the precision of the results was affected by the low numbers of donors with MSM as risk factor, or because of risk of bias in the included studies. All studies included low level evidence, because of risk of bias and imprecision of the results.

Conclusions

High-quality studies investigating the risk of TTI in MSM who donate blood are scarce. The available evidence suggests a link between MSM blood donors and HIV-1 infection, but is too limited to be able to unambiguously/clearly recommend a certain deferral policy.  相似文献   

15.
16.
The “Reading the Mind in the Eyes” test (Eyes test) is an advanced test of theory of mind. Typical sex difference has been reported (i.e., female advantage). Individuals with autism show more difficulty than do typically developing individuals, yet it remains unclear how this is modulated by sex, as females with autism have been under-represented. Here in a large, non-male-biased sample we test for the effects of sex, diagnosis, and their interaction. The Eyes test (revised version) was administered online to 395 adults with autism (178 males, 217 females) and 320 control adults (152 males, 168 females). Two-way ANOVA showed a significant sex-by-diagnosis interaction in total correct score (F(1,711) = 5.090, p = 0.024, ηp 2 = 0.007) arising from a significant sex difference between control males and females (p < 0.001, Cohen’s d = 0.47), and an absence of a sex difference between males and females with autism (p = 0.907, d = 0.01); significant case-control differences were observed across sexes, with effect sizes of d = 0.35 in males and d = 0.69 in females. Group-difference patterns fit with the extreme-male-brain (EMB) theory predictions. Eyes test-Empathy Quotient and Eyes test-Autism Spectrum Quotient correlations were significant only in females with autism (r = 0.35, r = -0.32, respectively), but not in the other 3 groups. Support vector machine (SVM) classification based on response pattern across all 36 items classified autism diagnosis with a relatively higher accuracy for females (72.2%) than males (65.8%). Nevertheless, an SVM model trained within one sex generalized equally well when applied to the other sex. Performance on the Eyes test is a sex-independent phenotypic characteristic of adults with autism, reflecting sex-common social difficulties, and provides support for the EMB theory predictions for both males and females. Performance of females with autism differed from same-sex controls more than did that of males with autism. Females with autism also showed stronger coherence between self-reported dispositional traits and Eyes test performance than all other groups.  相似文献   

17.
18.

Background

A large number of men who have sex with men (MSM) and people living with HIV/AIDS (PLHA) are underserved despite increased service availability from government facilities while many community based organizations (CBOs) are not involved. We aimed to assess the feasibility and effectiveness of the task shifting from government facilities to CBOs in China.

Methods

HIV preventive intervention for MSM and follow-up care for PLHA were shifted from government facilities to CBOs. Based on ‘cash on service delivery’ model, 10 USD per MSM tested for HIV with results notified, 82 USD per newly HIV cases diagnosed, and 50 USD per PLHA received a defined package of follow-up care services, were paid to the CBOs. Cash payments were made biannually based on the verified results in the national web-based HIV/AIDS information system.

Findings

After task shifting, CBOs gradually assumed preventive intervention for MSM and follow-up care for PLHA from 2008 to 2012. HIV testing coverage among MSM increased from 4.1% in 2008 to 22.7% in 2012. The baseline median CD4 counts of newly diagnosed HIV positive MSM increased from 309 to 397 cells/µL. HIV tests among MSM by CBOs accounted for less than 1% of the total HIV tests in Nanjing but the share of HIV cases detected by CBOs was 12.4% in 2008 and 43.6% in 2012. Unit cost per HIV case detected by CBOs was 47 times lower than that by government facilities. The coverage of CD4 tests and antiretroviral therapy increased from 71.1% and 78.6% in 2008 to 86.0% and 90.1% in 2012, respectively.

Conclusion

It is feasible to shift essential HIV services from government facilities to CBOs, and to verify independently service results to adopt ‘cash on service delivery’ model. Services provided by CBOs are cost-effective, as compared with that by government facilities.  相似文献   

19.
20.

Objective

This qualitative study explored the views and experiences of adolescents with perinatally acquired HIV in Kigali, Rwanda, regarding sex, love, marriage, children and hope for the future.

Design

The study enrolled 42 adolescents who had received combination antiretroviral therapy for at least 12 months, and a selection of their primary caregivers. Study methods included 3 multiple day workshops consisting of role-playing and focus group discussions (FGDs) with adolescents, 8 in-depth interviews with adolescents, and one FGD with caregivers.

Results

The adolescents reported experiencing similar sexual needs and dilemmas as most other adolescents, but with an added layer of complexity due to fears related to HIV transmission and/or rejection by partners. They desired more advice from their parents/caregivers on these topics. Although they struggled with aspects of sex, love, marriage and having children, most agreed that they would find love, be married and have children in the future. The two most discussed HIV-related anxieties were how and when to disclose to a (potential) sex/marriage partner and whether to have children. However, most adolescents felt that they had a right to love and be loved, and were aware of prevention-of-mother-to-child-transmission (PMTCT) options in Rwanda. Adolescents generally spoke about their future role in society in a positive manner.

Conclusion

Strengthening the life skills of HIV-positive adolescents, especially around HIV disclosure and reduction of HIV transmission, as well as the support skills of parents/caregivers, may not only reduce onward HIV transmission but also improve quality of life by reducing anxiety.  相似文献   

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