Sexual Partner Networks Research Articles

Prevalence and antimicrobial resistance profiles of Neisseria gonorrhea and Chlamydia trachomatis isolated from individuals attending STD clinics in Kampala, Uganda.

Sexually transmitted diseases (STDs) management in sub-Saharan Africa is syndromic but molecular diagnostics provide quicker, sensitive diagnosis and treatment. Effective STD control hinges on identification and treatment of infected persons and sexual partner contact tracing. This study assessed feasibility of using the Xpert CT/NG test to identify prevalent Chlamydia trachomatis (CT) and Neisseria gonorrhea (NG) infections among STD clinic attendees and their sexual partners and tested for antimicrobial resistance for N. gonorrhea. A cross-sectional study was conducted at 4 outpatient STD clinics in Kampala, Uganda from February 2019 to October 2019. Participants received a syndromic diagnosis, were tested for NG and CT, as well as their sexual partners. Urine (men) and high vaginal swabs (women) were collected, examined using Xpert CT/NG assay. A total of 79 participants were enrolled at baseline of whom 25 had CT/NG. 21 partners of infected baseline participants and 7 partners of the 21 primary partners were enrolled. The mean age of the reported sexual partners was 26 (18-43) years. The prevalence of NG was 25% at baseline and 18 % for CT. Nine (11.4%) people were dually infected. Men were more likely to have NG (p<0.001) at multivariable level. Two participants tested HIV-1 positive. On microbiological culture, 8 samples (2.5%) grew NG and all were resistant to penicillin, ciprofloxacin. For CT, we found a preponderance of the F-serovar in this population. The most prevalent organism was Neisseria gonorrhea. Generally, the prevalence of CT and NG was high. Infection proportions increased among primary partners, particularly women. Etiologic testing without partner tracing and treatment may underestimate burden of CT/NG in this population and contribute to re-infection.

Social networks of men who have sex with men: a study of recruitment chains using Respondent Driven Sampling in Salvador, Bahia State, Brazil.

Social and sexual contact networks between men who have sex with men (MSM) play an important role in understanding the transmission of HIV and other sexually transmitted infections (STIs). In Salvador (Bahia State, Brazil), one of the cities in the survey Behavior, Attitudes, Practices, and Prevalence of HIV and Syphilis among Men Who Have Sex with Men in 10 Brazilian Cities, data were collected in 2008/2009 from a sample of 383 MSM using Respondent Driven Sampling (RDS). Network analysis was used to study friendship networks and sexual partner networks. The study also focused on the association between the number of links (degree) and the number of sexual partners, in addition to socio-demographic characteristics. The networks' structure potentially facilitates HIV transmission. However, the same networks can also be used to spread messages on STI/HIV prevention, since the proximity and similarity of MSM in these networks can encourage behavior change and positive attitudes towards prevention.

Sexual practices, partner concurrency and high rates of sexually transmissible infections among male sex workers in three cities in Vietnam.

Background This paper examines sexual practices, partner concurrency and sexually transmissible infections (STI)/HIV infection among male sex workers (MSWs) in Vietnam. Six hundred and fifty-four MSWs, aged 16-35 years, were recruited in Hanoi, Nha Trang and Ho Chi Minh City between 2009 and 2011. Survey measures included demographic characteristics, drug use, types of sexual partners and sexual practices. Subjects were screened for STIs, including HIV. MSWs in Ho Chi Minh City (33%) were more likely than those from the other two sites to be current users of one or more types of illegal drugs (P<0.001). MSWs with both male and female elective partners (compared with other partnership types) were more likely to have anal sex with male client partners (P<0.001), elective male partners (P=0.045) and elective female partners (P=0.025). At last sex with a male client partner, only 30% used a condom during anal intercourse. At last sex with an elective female partner, only 31% used a condom during vaginal sex and only 3% during anal sex. Although rates of HIV are low (4%), other STIs are high, including chlamydia (17%), gonorrhoea (29%) and human papillomavirus (33%). Most (57.3%) have never been tested for HIV and only 17% have ever disclosed to a healthcare provider that they have sex with men. Complex patterns of sexual concurrency, coupled with high rates of STIs, signal the urgent need for health services interventions among MSWs, both to improve individual health outcomes and to reduce secondary STI/HIV transmission among sexual partner networks.

P4.128 American Indian Emerging Adults: Partnership Formation and HIV Risk and Protective Factors

Multiple challenges such as high rates of discrimination, poverty and traumatic events, expose American Indian (AI) women to high-risk sexual partnerships placing them at an increased risk for HIV/STI. Characterizing...

Frailty Effects in Networks: Comparison and Identification of Individual HeterogeneityVersusPreferential Attachment in Evolving Networks

Preferential attachment is a proportionate growth process in networks, where nodes receive new links in proportion to their current degree. Preferential attachment is a popular generative mechanism to explain the widespread observation of power-law-distributed networks. An alternative explanation for the phenomenon is a randomly grown network with large individual variation in growth rates among the nodes (frailty). We derive analytically the distribution of individual rates, which will reproduce the connectivity distribution that is obtained from a general preferential attachment process (Yule process), and the structural differences between the two types of graphs are examined by simulations. We present a statistical test to distinguish the two generative mechanisms from each other and we apply the test to both simulated data and two real data sets of scientific citation and sexual partner networks. The findings from the latter analyses argue for frailty effects as an important mechanism underlying the dynamics of complex networks.

New Thinking in HIV Prevention: An Anthropological and Epidemiological Viewpoint

Prior to his current faculty position in the Department of Global Health and Population at the Harvard School of Public Health, Halperin served for over 5 years as the Senior HIV Prevention and Behavior Change Advisor at the USA Agency for International Development. Halperin has conducted epidemiological and ethnographic research for 30 years on a number of health and sociocultural issues in Latin America, sub-Saharan Africa and other developing regions. Since completing his doctoral training in medical and cultural anthropology at the University of California, Berkeley, in 1995, his work has mainly focused on the heterosexual transmission of HIV and other sexually transmitted infections. Most of Halperin's research and scientific publications have dealt with some of the previously more neglected HIV co-factors, such as concurrent sexual partner networks, lack of male circumcision, ‘dry sex’ practices, alcohol use and heterosexual anal intercourse. He has conducted field research and consultations over the years in a number of countries, including Brazil, South Africa, Botswana, Zimbabwe, Mozambique, Haiti, the Dominican Republic and Peru.

Risks of acquiring and transmitting sexually transmitted diseases in sexual partner networks.

A person's risk for acquiring infection and their role in continued transmission has traditionally been assessed on the basis of individual characteristics. Recently, network studies have attempted to relate individual risks to position in the wider network. To assess the importance of local and global network structures in assessing the risk of acquiring and transmitting infection. An individual-based simulation model was used to construct a variety of potential network structures and track the transmission of infection over time. Logistic and Poisson regression were used to identify which measures of network position influence a person's risk for acquiring and transmitting infection. Measures of local centrality were more important to risk of acquisition, whereas global centrality mattered more to transmission. Continuous snowball sampling, rather than a fixed number of waves, better estimates a person's risks. There is an asymmetry regarding the risk of acquiring and transmitting infection.

Measuring Sexual Partner Networks for Transmission of Sexually Transmitted Diseases

Summary Patterns of sexual mixing and the sexual partner network are important determinants of the spread of all sexually transmitted diseases (STDs), including the human immunodeficiency virus. Novel statistical problems arise in the analysis and interpretation of studies aimed at measuring patterns of sexual mixing and sexual partner networks. Samples of mixing patterns and network structures derived from randomly sampling individuals are not themselves random samples of measures of partnerships or networks. In addition, the sensitive nature of questions on sexual activity will result in the introduction of non-response biases, which in estimating network structures are likely to be non-ignorable. Adjusting estimates for these biases by using standard statistical approaches is complicated by the complex interactions between the mechanisms generating bias and the non-independent nature of network data. Using a two-step Monte Carlo simulation approach, we have shown that measures of mixing patterns and the network structure that do not account for missing data and non-random sampling are severely biased. Here, we use this approach to adjust raw estimates in data to incorporate these effects. The results suggest that the risk for transmission of STDs in empirical data is underestimated by ignoring missing data and non-random sampling.

Sexual partner networks in the transmission of sexually transmitted diseases. An analysis of gonorrhea cases in Sheffield, UK.

Routine contact tracing data on patients with gonorrhea are used to identify sexual partner networks. These are combined with gonococcal typing data to study patterns of transmission. The role of persons in transmission is discussed. Contact tracing data on patients with gonorrhea attending the Royal Hallamshire Hospital in Sheffield in 1988 and 1989 are analyzed. Gonococcal strains identified by auxotype/serovar (A/S) class are combined with these data to identify transmission paths. The network contained 1,272 persons, 724 (77%) of whom had gonorrhea during the study period. Four hundred two clusters of linked cases were identified. The largest cluster, containing 35 persons connected over 16 months, is discussed in greater detail to illustrate how these data may help identify patterns of transmission and the role of persons. Contact tracing data can be used to identify sexual partner networks and to study transmission patterns. Microbiologic data can aid interpretation. An person's risk of acquiring infection depends on indirect links as well as direct links. To understand patterns of transmission it may be important to distinguish between those involved in transmission and those only acquiring infection. Networks established through gonococcal transmission are also relevant to the transmission of other sexually transmitted diseases.