The dynamics of substance use and sex networks in HIV transmission

Targeted maximum likelihood estimation of causal effects with interference: A simulation study

Interference, the dependency of an individual's potential outcome on the exposure of other individuals, is a common occurrence in medicine and public health. Recently, targeted maximum likelihood estimation (TMLE) has been extended to settings of interference, including in the context of estimation of the mean of an outcome under a specified distribution of exposure, referred to as a policy. This paper summarizes how TMLE for independent data is extended to general interference (network-TMLE). An extensive simulation study is presented of network-TMLE, consisting of four data generating mechanisms (unit-treatment effect only, spillover effects only, unit-treatment and spillover effects, infection transmission) in networks of varying structures. Simulations show that network-TMLE performs well across scenarios with interference, but issues manifest when policies are not well-supported by the observed data, potentially leading to poor confidence interval coverage. Guidance for practical application, freely available software, and areas of future work are provided.

Neighborhoods and HIV: a social ecological approach to prevention and care

Neighborhood factors have been linked to HIV risk behaviors, HIV counseling and testing, and HIV medical care. However, the social-psychological mechanisms that connect neighborhood factors to HIV-related behaviors have not been fully determined. In this article we review the research on neighborhood factors and HIV-related behaviors, approaches to measuring neighborhoods, and mechanisms that may help to explain how the physical and social environment within neighborhoods may lead to HIV-related behaviors. We then discuss organizational, geographic, and social network approaches to intervening in neighborhoods to reduce HIV transmission and facilitate HIV medical care with the goal of reducing morbidity and mortality and increasing social and psychological well-being.

Substance use and sexually transmitted infections among anti-retroviral treatment attendees in jimma university specialized hospital, jimma, ethiopia

BACKGROUND

Substance use increases both the risk of Human Immunodeficiency Virus and other Sexually Transmitted Infections, either directly or indirectly. The association of substance use and Sexually Transmitted Infections has not yet studied in Southwestern Ethiopia. The main aim of this study is to determine the associations between substance use and Sexually Transmitted Infections on clients under follow up in Anti-Retroviral Treatment clinic at Jimma University Specialized Hospital.

METHODS

A cross-sectional study was conducted on clients under follow up at Anti-Retroviral Treatment clinic from June 10 to July 10, 2011 at Jimma University Specialized Hospital. Data collection was done using a pre-coded and pre-tested questionnaire. Trained Anti-Retroviral Treatment adherence counselors collected the data. Data were entered and analyzed using SPSS for Windows version 16.0. Chi-square test was used to measure the levels of significance. P-value < 0.05 was considered as significant.

RESULTS

Three hundred thirty eight Anti-Retroviral Treatment attendees participated in the study. Two hundred twenty (65.1%) of the study participants were females and their mean (±SD) age was 33.6 ± 8.04 years while 156 (46.2%) of them lied in the age group of 25-34 years. Clients who reported that they had Sexually Transmitted Infections were 120 (35.5%). Those who consumed alcohol were more likely to have contracted in Sexually Transmitted Infections: AOR (95% CI) =0.46 (0.26-0.80).

CONCLUSION

Prevalence of Sexually Transmitted Infections was comparable among females and males. Substance use, particularly alcohol consumption, found to be a potential risk factor for Sexually Transmitted Infections.

The relationship between social network factors, HIV, and Hepatitis C among injection drug users in Chennai, India

OBJECTIVE

The purpose of this study was to examine whether social network factors predict HIV and Hepatitis C (HCV) serostatus after controlling for individual-level factors at baseline among a cohort of male injection drug users in Chennai, India.

METHODS

The sample, which was recruited through street outreach, consists of 1078 males who reported having injected drugs in the last 6 months.

RESULTS

The participants reported 3936 social support and risk network members. HIV and HCV positive serostatus were negatively associated with network member providing emotional support, and positively associated with network member providing material support. In addition, HCV positivity was associated with network member being an active drug user known for more than 10 years and network member being male kin networks, even after adjusting for individual demographic factors and risk behaviors.

CONCLUSIONS

These findings suggest that social network factors are significantly linked to HIV and HCV status among IDUs in Southern India and highlight the mixed effects of social capital on health. Future HIV/HCV prevention efforts should incorporate IDU peers to alter drug network injection risk norms. For drug users who have minimal network support, support groups and other informal and formal support mechanisms may be need to help them with health care and psychological support needs for dealing with HIV/HCV.

Correlation between HIV and sexual behavior, drug use, trichomoniasis and candidiasis among female sex workers in a Mekong Delta province of Vietnam

To determine the prevalence of HIV and correlates of HIV infection among female sex workers (FSWs) in Soc Trang province, Vietnam, a survey of 406 FSWs in Soc Trang province was conducted between May and August, 2003. The participants were interviewed, using a standardized interview, to obtain information about socio-demographic and behavioral characteristics, and gynecologic and sexually transmitted infection (STI) history. The prevalence of HIV was 3.3%. An increased risk for HIV was associated with ever using illicit drugs, direct sex work, early sexual debut, age of FSWs, and infection with candidiasis and trichomoniasis. Reduced likelihood of HIV was only associated with withdrawal as a contraceptive method. A strong association of HIV with drug use and candidiasis and trichomoniasis infection among FSWs was found. Needle/syringe exchange, STI treatment, and methadone programs targeting FSWs should be implemented, and should include 100% condom use promotion.

HIV, the clustering of sexually transmitted infections, and sex risk among African American women who use drugs

African American women have high rates of most sexually transmitted infections (STIs), including HIV. STIs have been associated with increased HIV transmission risk.

METHODS

Two hundred twenty-eight black women who used drugs completed a structured questionnaire in a central Brooklyn, NY-based research center between March 2003 and August 2005. Women were screened for HIV, herpes simplex virus-2, syphilis, gonorrhea, chlamydia, and trichomoniasis. This analysis determined if STIs cluster within individuals and if clustering and sex practices or partnerships differ by HIV status.

RESULTS

Thirty-eight (17%) women tested HIV seropositive and STI prevalence was herpes simplex virus-2 (79%), trichomoniasis (37%), chlamydia (11%), and gonorrhea (2%). Few women knew themselves to be infected with STIs other than HIV. Excluding HIV, the mean number of STIs per woman was 1.3 (SD 0.7). HIV-infected women were significantly more likely than uninfected women to have multiple positive screens (1.6 vs. 1.2, P = 0.002). Women reported having both lower and higher risk sex partners. HIV-infected women were 2 times more likely than uninfected woman to report current sex work (P = 0.05), the only difference in sex risk. In a linear regression model, crack cocaine use was uniquely associated with multiple positive STI screens, excluding HIV (P = 0.002).

CONCLUSIONS

Several STIs, including HIV, seem to be endemic among black women who use drugs in this community. In addition to the known geographical clustering of HIV and STIs, STIs were also found to cluster at the individual level. Multiply STI infected individuals may unknowingly, but efficiently, contribute to high STI and HIV rates.

Molecular targets of opiate drug abuse in neuroAIDS

Opiate drug abuse, through selective actions at mu-opioid receptors (MOR), exacerbates the pathogenesis of human immunodeficiency virus-1 (HIV-1) in the CNS by disrupting glial homeostasis, increasing inflammation, and decreasing the threshold for pro-apoptotic events in neurons. Neurons are affected directly and indirectly by opiate-HIV interactions. Although most opiates drugs have some affinity for kappa (KOR) and/or delta (DOR) opioid receptors, their neurotoxic effects are largely mediated through MOR. Besides direct actions on the neurons themselves, opiates directly affect MOR-expressing astrocytes and microglia. Because of their broad-reaching actions in glia, opiate abuse causes widespread metabolic derangement, inflammation, and the disruption of neuron-glial relationships, which likely contribute to neuronal dysfunction, death, and HIV encephalitis. In addition to direct actions on neural cells, opioids modulate inflammation and disrupt normal intercellular interactions among immunocytes (macrophages and lymphocytes), which on balance further promote neuronal dysfunction and death. The neural pathways involved in opiate enhancement of HIV-induced inflammation and cell death, appear to involve MOR activation with downstream effects through PI3-kinase/Akt and/or MAPK signaling, which suggests possible targets for therapeutic intervention in neuroAIDS.