Improving survey methods in sero-epidemiological studies of injecting drug users: a case example of two cross sectional surveys in Serbia and Montenegro

BACKGROUND: Little is known about the prevalence of HIV or HCV in injecting drug users (IDUs) in Serbia and Montenegro. We measured prevalence of antibodies to HIV (anti-HIV) and hepatitis C virus (anti-HCV), and risk factors for anti-HCV, in community-recruited IDUs in Belgrade and Podgorica, and determined the performance of a parallel rapid HIV testing algorithm. METHODS: Respondent driven sampling and audio-computer assisted survey interviewing (ACASI) methods were employed. Dried blood spots were collected for unlinked anonymous antibody testing. Belgrade IDUs were offered voluntary confidential rapid HIV testing using a parallel testing algorithm, the performance of which was compared with standard laboratory tests. Predictors of anti-HCV positivity and the diagnostic accuracy of the rapid HIV test algorithm were calculated. RESULTS: Overall population prevalence of anti-HIV and anti-HCV in IDUs were 3% and 63% respectively in Belgrade (n = 433) and 0% and 22% in Podgorica (n = 328). Around a quarter of IDUs in each city had injected with used needles and syringes in the last four weeks. In both cities anti-HCV positivity was associated with increasing number of years injecting (eg Belgrade adjusted odds ratio (AOR) 5.6 (95% CI 3.2-9.7) and Podgorica AOR 2.5 (1.3-5.1) for >or= 10 years v 0-4 years), daily injecting (Belgrade AOR 1.6 (1.0-2.7), Podgorica AOR 2.1 (1.3-5.1)), and having ever shared used needles/syringes (Belgrade AOR 2.3 (1.0-5.4), Podgorica AOR 1.9 (1.4-2.6)). Half (47%) of Belgrade participants accepted rapid HIV testing, and there was complete concordance between rapid test results and subsequent confirmatory laboratory tests (sensitivity 100% (95%CI 59%-100%), specificity 100% (95%CI 98%-100%)). CONCLUSION: The combination of community recruitment, ACASI, rapid testing and a linked diagnostic accuracy study provide enhanced methods for conducting blood borne virus sero-prevalence studies in IDUs. The relatively high uptake of rapid testing suggests that introducing this method in community settings could increase the number of people tested in high risk populations. The high prevalence of HCV and relatively high prevalence of injecting risk behaviour indicate that further HIV transmission is likely in IDUs in both cities. Urgent scale up of HIV prevention interventions is needed

Simultaneous Recruitment of Drug Users and Men Who Have Sex with Men in the United States and Russia Using Respondent-Driven Sampling: Sampling Methods and Implications

The Sexual Acquisition and Transmission of HIV Cooperative Agreement Program (SATHCAP) examined the role of drug use in the sexual transmission of the human immunodeficiency virus (HIV) from traditional high-risk groups, such as men who have sex with men (MSM) and drug users (DU), to lower risk groups in three US cities and in St. Petersburg, Russia. SATHCAP employed respondent-driven sampling (RDS) and a dual high-risk group sampling approach that relied on peer recruitment for a combined, overlapping sample of MSM and DU. The goal of the sampling approach was to recruit an RDS sample of MSM, DU, and individuals who were both MSM and DU (MSM/DU), as well as a sample of sex partners of MSM, DU, and MSM/DU and sex partners of sex partners. The approach efficiently yielded a sample of 8,355 participants, including sex partners, across all four sites. At the US sites—Los Angeles, Chicago, and Raleigh–Durham—the sample consisted of older (mean age = 41 years), primarily black MSM and DU (both injecting and non-injecting); in St. Petersburg, the sample consisted of primarily younger (mean age = 28 years) MSM and DU (injecting). The US sites recruited a large proportion of men who have sex with men and with women, an important group with high potential for establishing a generalized HIV epidemic involving women. The advantage of using the dual high-risk group approach and RDS was, for the most part, the large, efficiently recruited samples of MSM, DU, and MSM/DU. The disadvantages were a recruitment bias by race/ethnicity and income status (at the US sites) and under-enrollment of MSM samples because of short recruitment chains (at the Russian site)

Redes Sociais e Comportamento Sexual: para uma visão relacional da sexualidade, do risco e da prevenção

Com base num inquérito representativo da população portuguesa entre 18 e 65 anos, realizado em 2007, este estudo investiga o impacto de fatores de rede social sobre os comportamentos sexuais dos indivíduos. Através da percepção normativa dos inquiridos sobre a moral sexual dos seus amigos e familiares e de indicadores relativos à caracterização da rede de confidência sexual, tais como o número, a identidade, o gênero, a idade e o comportamento dos confidentes em matéria de sexualidade e prevenção face ao risco de infecção por DSTs, obtivemos um retrato multidimensional das redes sociais dos indivíduos. A realização de análises de regressão linear e logística permitiu avaliar o impacto preditivo da rede sobre o número de parceiros sexuais, as relações sexuais ocasionais e o uso do preservativo. Os dados mostram que os fatores de rede são importantes para explicar o comportamento sexual dos indivíduos. Redes constituídas por amigos e mais liberais em termos de moral sexual tendem a influenciar o comportamento sexual, levando a um maior experimentalismo, sobretudo no caso das mulheres. Por outro lado, a homologia entre o comportamento sexual dos confidentes e o dos inquiridos é relevante para explicar o recurso ao preservativo nas relações sexuais ocasionais, especialmente no caso dos homens. Tanto numa perspectiva relacional da sexualidade como numa óptica epidemiológica, a análise das redes sociais dos indivíduos constitui um aspecto importante para a compreensão e explicação da variedade de experiências sexuais, mais restritas ou mais plurais, e para os riscos de infecção que daí podem advir

Does Respondent Driven Sampling Alter the Social Network Composition and Health-Seeking Behaviors of Illicit Drug Users Followed Prospectively?

Respondent driven sampling (RDS) was originally developed to sample and provide peer education to injection drug users at risk for HIV. Based on the premise that drug users' social networks were maintained through sharing rituals, this peer-driven approach to disseminate educational information and reduce risk behaviors capitalizes and expands upon the norms that sustain these relationships. Compared with traditional outreach interventions, peer-driven interventions produce greater reductions in HIV risk behaviors and adoption of safer behaviors over time, however, control and intervention groups are not similarly recruited. As peer-recruitment may alter risk networks and individual risk behaviors over time, such comparison studies are unable to isolate the effect of a peer-delivered intervention. This analysis examines whether RDS recruitment (without an intervention) is associated with changes in health-seeking behaviors and network composition over 6 months. New York City drug users (N = 618) were recruited using targeted street outreach (TSO) and RDS (2006–2009). 329 non-injectors (RDS = 237; TSO = 92) completed baseline and 6-month surveys ascertaining demographic, drug use, and network characteristics. Chi-square and t-tests compared RDS- and TSO-recruited participants on changes in HIV testing and drug treatment utilization and in the proportion of drug using, sex, incarcerated and social support networks over the follow-up period. The sample was 66% male, 24% Hispanic, 69% black, 62% homeless, and the median age was 35. At baseline, the median network size was 3, 86% used crack, 70% used cocaine, 40% used heroin, and in the past 6 months 72% were tested for HIV and 46% were enrolled in drug treatment. There were no significant differences by recruitment strategy with respect to changes in health-seeking behaviors or network composition over 6 months. These findings suggest no association between RDS recruitment and changes in network composition or HIV risk, which supports prior findings from prospective HIV behavioral surveillance and intervention studies

The Relative Role of Perceived Partner Risks in Promoting Condom Use in a Three-City Sample of High-Risk, Low-Income Women

We examined the effect of women’s perceptions of sexual partner risks on condom use. Women from three US cities (n = 1,967) were recruited to provide data on HIV risks. In univariate models, increased odds of condom use were associated with perceiving that partners had concurrent partners and being unaware of partners': (a) HIV status, (b) bisexuality, (c) concurrency; and/or (d) injection drug use. In multivariate models, neither being unaware of the four partner risk factors nor perceiving a partner as being high risk was associated with condom use. Contextual factors associated with decreased odds of condom use were having sex with a main partner, homelessness in the past year, alcohol use during sex, and crack use in the past 30 days. Awareness of a partner’s risks may not be sufficient for increasing condom use. Contextual factors, sex with a main partner in particular, decrease condom use despite awareness of partner risk factors

The Criminal Justice Experience of African American Cocaine Users in Arkansas

BackgroundAfrican Americans are incarcerated at rates much higher than other racial and ethnic groups in the United States.ObjectivesWe sought to qualitatively explore the relationships between ongoing involvement in the criminal justice system and continued drug use in a population of urban and rural African American cocaine users in a southern state.MethodsSemi-structured qualitative interviews were conducted among African American cocaine users in Arkansas between 2010 and 2012. Participants resided in both rural (two counties located in the eastern Arkansas Mississippi delta region) and urban (the county including the capital city of Little Rock) areas.ResultsNumerous important themes emerged from participants' narratives, including chronic involvement with the criminal justice system (being a "career criminal"), continued access to drugs while incarcerated, relapse, and reincarceration and lack of access to effective drug treatment. Conclusion/Importance: The themes which emerged from our data speak to the collective experience that many substance using populations in the United States face in dealing with the criminal justice system. Our findings highlight the need to better, more holistic ways of engaging African American substance users in community based substance use treatment and supportive services

Elevated CO2 affects plant responses to variation in boron availability

Aim Effects of elevated CO2 on N relations are well studied, but effects on other nutrients, especially micronutrients, are not. We investigated effects of elevated CO2 on response to variation in boron (B) availability in three unrelated species: seed geranium (Pelargonium x hortorum), barley (Hordeum vulgare), and water fern (Azolla caroliniana). Methods Plants were grown at two levels of CO2 (370, 700 ppm) and low, medium, and high B. Treatment effects were measured on biomass, net photosynthesis (Pn) and related variables, tissue nutrient concentrations, and B transporter protein BOR1. Results In geranium, there were interactive effects (P\u3c 0.05) of B and CO2 on leaf, stem, and total plant mass, root:shoot ratio, leaf [B], B uptake rate, root [Zn], and Pn. Elevated CO2 stimulated growth at 45 μM B, but decreased it at 450 μM B and did not affect it at 4.5 μM B. Pn was stimulated by elevated CO2 only at 45 μM B and chlorophyll was enhanced only at 450 μM B. Soluble sugars increased with high CO2 only at 4.5 and 45 μM B. High CO2 decreased leaf [B] and B uptake rate, especially at 450 μM B. Though CO2 and B individually affected the concentration of several other nutrients, B x CO2 interactions were evident only for Zn in roots, wherein [Zn] decreased under elevated CO2. Interactive effects of B and CO2 on growth were confirmed in (1) barley grown at 0, 30, or 1,000 μM B, wherein growth at high CO2 was stimulated more at 30 μM B, and (2) Azolla grown at 0, 10, and 1,000 μM B, wherein growth at high CO2 was stimulated at 0 and 10 μM B. Conclusion Thus, low and high B both may limit growth stimulation under elevated vs. current [CO2], and B deficiency and toxicity, already common, may increase in the future

Elevated CO₂ Increases Severity of Thermal Hyponasty in Leaves of Tomato

We previously showed that chronic warming plus elevated carbon dioxide (eCO2) causes extreme upward bending of leaflets and petioles (i.e., hyponasty) in tomato (Solanum lycopersicum), which reduces growth. In that study, only two levels of CO2 (400, 700 ppm) and temperature (30, 37 °C) were tested in young vegetative plants, and the underlying mechanism for warming + eCO2 hyponasty was not investigated. In this study, warming + eCO2 hyponasty was evaluated in tomato across a range of temperatures and CO2 concentrations, and at multiple life stages. Based on their roles in thermal hyponasty, ethylene and auxin tomato mutants were examined, and light quality manipulated, to explore the mechanism for warming + eCO2 hyponasty. At eCO2 (800 ppm), the petiole angle increased roughly linearly with temperature from 30 to 38 °C. Under high temperature stress (38 °C), the petiole angle increased similarly at all eCO2 concentrations (600/800/1000 vs. 400 ppm). All life stages examined had an increased petiole angle in leaves developed during warming + eCO2, such that most leaves in juvenile plants exhibited hyponasty but only young growing leaves did so in adults. Auxin-insensitive mutants displayed a reduced petiole angle compared to auxin-sensitive, ethylene-sensitive, ethylene-insensitive, and non-mutant genotypes, indicating that auxin, but not ethylene, is likely a main component of this hyponastic response. Reduced far-red-to-red light plus increased blue light reduced petiole hyponasty compared to non-filtered white light during warming + eCO2. These results indicate that eCO2 affects the well-characterized thermal hyponastic response of leaves, which has implications for future plant responses to climate change