To describe the spread of hepatitis C virus (HCV) among HCV/human immunodeficiency virus (HIV)–coinfected injection drug users (IDUs), the molecular epidemiology of HCV was studied among 108 IDUs ...from 7 European countries. Phylogenetic analysis based on the NS5B region showed great sequence variation of HCV within each country and no clear phylogenetic clustering by geographic region. The most prevalent subtypes were 1a and 3a, but the percentage of genotype 4 was also relatively high, ranging from 7% in northern Europe to 24% in southern Europe. Genotype 4 consisted mainly of subtype 4d and has entered the majority of the IDU populations studied. The significantly lower evolutionary distances within subtype 4d suggest that this subtype may have entered the European IDU population relatively recently. In conclusion, HCV exchange between European IDU populations has occurred on a large scale, and, overall, country-specific clustering for HCV was less than that shown for HIV
We traced the Chlamydia trachomatis L2b variant in Amsterdam and San Francisco. All recent lymphogranuloma venereum cases in Amsterdam were caused by the L2b variant. This variant was also present in ...the 1980s in San Francisco. Thus, the current "outbreak" is most likely a slowly evolving epidemic.
To investigate longitudinally the association between highly active antiretroviral therapy (HAART)-related beliefs and the change from protected to unprotected anal intercourse with casual partners ...on an individual level.
The study population included 217 HIV-negative homosexual men participating in the Amsterdam Cohort Study from September 1999 to May 2002, including five data waves with a 6-month interval. The selection criteria were: being under 31 years of age, having had anal sex with casual partners in the preceding 6 months, and participating in at least two data waves. Information was collected on the individual change from protected to unprotected receptive anal intercourse (URAI) and unprotected insertive anal intercourse (UIAI) and the level of agreement with different HAART-related beliefs.
The majority of men disagreed with the three treatment-belief factors that resulted from the principal component analysis: perceiving less HIV/AIDS threat since HAART, perceiving less need for safe sex since HAART, and perceiving high effectiveness of HAART in curing HIV/AIDS. Multivariate analyses revealed that the more men inclined to agree with the belief 'perceiving less HIV/AIDS threat', the more likely they were to change to URAI (adjusted OR 1.60; 95% CI 1.16-2.22).
Homosexual men are quite realistic about the effectiveness of HAART, the continued need for condom use, and the HIV/AIDS threat since HAART. However, a tendency towards agreement with 'perceiving less HIV/AIDS threat' was found to predict an individuals' change to URAI. This finding supports the hypothesis of a causal relationship between decreased HIV/AIDS threat since HAART and a change to URAI.
Background: Recreational drug use is associated with high-risk sexual behavior and sexually transmitted infections (STIs). We assessed the prevalence of drug use during sex and the associations ...between such use and STI (chlamydia, gonorrhea, or syphilis). Methods: During 3 periods in 2008 and 2009, attendees of an STI clinic in Amsterdam were interviewed about sexual behavior and drug use during sex and tested for STI. Associations between sex-related drug use and STI were assessed separately for heterosexual men, men who have sex with men (MSM), and women. We examined whether drug use was associated with STI after adjusting for high-risk sexual behavior. Results: Nine hundred sixty-one heterosexual men, 673 MSM, and 1188 women participated in this study. Of these, 11.9% had chlamydia, 3.4% gonorrhea, and 1.2% syphilis. Sex-related drug use in the previous 6 months was reported by 22.6% of heterosexual men, 51.6% of MSM, and 16.0% of women. In multivariable analyses, adjusting for demographics (and high-risk sexual behavior in MSM), sex-related drug use was associated with STI in MSM (any drugs and poppers) and women (GHB and XTC) but not in heterosexual men. Stratified analysis in MSM showed that sex-related use of poppers was associated with STI in HIV-negative MSM but not in HIV-infected MSM. Conclusion: Clients reported frequent sex-related drug use, which was associated with STI in MSM and women. In MSM, sex-related drug use was associated with STI after adjusting for high-risk sexual behavior but only in HIV-negative MSM. Prevention measures targeted at decreasing sex-related drug use could reduce the incidence of STI.
BackgroundThe effect that GB virus C (GBV-C) coinfection has on human immunodeficiency virus type 1 (HIV-1) disease progression is controversial and therefore was studied in 326 homosexual men from ...the prospective Amsterdam Cohort Studies who had an accurately estimated date of HIV-1 seroconversion and were followed up for a median period of 8 years MethodsA first plasma sample, obtained shortly after HIV-1 seroconversion, and a last plasma sample, obtained before 1996, were tested for GBV-C RNA and envelope protein–2 antibodies. The effect that GBV-C has on HIV-1 disease progression was studied by use of time-dependent Cox proportional-hazards models with adjustment for baseline variables and time-updated HIV-1 RNA and CD4+ cell count ResultsMen who lost GBV-C RNA between collection of the first sample and collection of the last sample had a nearly 3-fold-higher risk of HIV-1 disease progression than did men who had never had GBV-C RNA. This effect became much smaller after adjustment for time-updated CD4+ cell count ConclusionRather than a positive effect of GBV-C RNA presence, a negative effect of GBV-C RNA loss on HIV-1 disease progression was found, which disappeared after adjustment for time-updated CD4+ cell count. We therefore hypothesize that GBV-C RNA persistence depends on the presence of a sufficient number of CD4+ cells—and that the CD4+ cell decrease associated with HIV-1 disease progression is a cause, not a consequence, of GBV-C RNA loss
IS6110 fingerprinting of Mycobacterium tuberculosis is the standard identification method in studies on transmission of tuberculosis. However, intensive epidemiological investigation may fail to ...confirm transmission links between patients clustered by IS6110-restriction fragment length polymorphism (RFLP) typing. We applied typing based on variable numbers of tandem repeats (VNTRs) of mycobacterial interspersed repetitive units (MIRUs) to isolates from 125 patients in 42 IS6110 clusters, for which thorough epidemiological data were available, to investigate the potential of this method in distinguishing epidemiologically linked from nonlinked patients. Of seven IS6110 clusters without epidemiological links, five were split by MIRU-VNTR typing, while nearly all IS6110 clusters with proven or likely links displayed conserved MIRU-VNTR types. These results provide molecular evidence that not all clusters determined on the basis of multibanded IS6110 RFLP patterns necessarily reflect transmission of tuberculosis. They support the use of MIRU-VNTR typing as a more reliable and faster method for transmission analysis.
We performed a molecular phylogenetic study on HIV-1 polymerase sequences of men who have sex with men (MSM) and heterosexual patient samples in Kenya to characterize any observed HIV-1 transmission ...networks. HIV-1 polymerase sequences were obtained from samples in Nairobi and coastal Kenya from 84 MSM, 226 other men, and 364 women from 2005 to 2010. Using Bayesian phylogenetics, we tested whether sequences clustered by sexual orientation and geographic location. In addition, we used trait diffusion analyses to identify significant epidemiological links and to quantify the number of transmissions between risk groups. Finally, we compared 84 MSM sequences with all HIV-1 sequences available online at GenBank. Significant clustering of sequences from MSM at both coastal Kenya and Nairobi was found, with evidence of HIV-1 transmission between both locations. Although a transmission pair between a coastal MSM and woman was confirmed, no significant HIV-1 transmission was evident between MSM and the comparison population for the predominant subtype A (60%). However, a weak but significant link was evident when studying all subtypes together. GenBank comparison did not reveal other important transmission links. Our data suggest infrequent intermingling of MSM and heterosexual HIV-1 epidemics in Kenya.
Although hepatitis C virus (HCV) treatment has shown to be effective, uptake of treatment among active drug users is still low. The Drug Users Treatment for Chronic Hepatitis-C project aims to offer ...active drug users in Amsterdam HCV testing and treatment using a multidisciplinary approach.
The study population comprises drug users participating in the Amsterdam Cohort Studies and drug users referred to the Drug Users Treatment for Chronic Hepatitis-C unit. Drug users were offered HCV testing and, if chronically infected, medical and psychiatric screening and HCV treatment. Various specialists collaborated to provide optimal care. We assessed test-uptake and treatment-uptake and outcomes.
Four hundred and ninety-seven Amsterdam Cohort Studies drug users were offered HCV testing: 449 out of 497 (90%) accepted. HCV antibodies were found in 267 out of 449 (60%): 183 out of 267 (69%) were HCV-viremic and 49 out of 183 (27%) were HIV-co-infected. Of the 134 HCV-monoinfected patients, 102 (76%) initiated additional medical screening and 44 started treatment by 1 July 2009. Sixty-two drug users referred from methadone clinics were also HCV-monoinfected, of whom 14 started treatment by 1 July 2009. In total 58 persons were treated: 16 (27%) with genotype 1 or 4, 42 (72%) with genotype 2 or 3. Eighty-four percent used methadone, 97% used drugs (heroin, cocaine or amphetamine) at least once in the 6 months before treatment, 19% were active injectors. Sixty-two percent used alcohol, 41% had psychiatric disease other than substance abuse. Of the 57 individuals with sufficient follow-up, 37 (65%) achieved sustained virological response.
In a multidisciplinary setting, HIV-negative drug users with chronic HCV infection can be treated successfully despite active drug or alcohol use and psychiatric diseases. Therefore, access to HCV therapy using an integrated approach should be increased for this population.
To compare the population dynamics of HIV-2 and HIV-1, and to characterize ongoing HIV-2 transmission in rural Guinea-Bissau.
Phylogenetic and phylodynamic analyses using HIV-2 gag and env, and HIV-1 ...env sequences, combined with epidemiological data from a community cohort.
Samples were obtained from surveys in 1989-1991, 1996-1997, 2003 and 2006-2007. Phylogenies were reconstructed using sequences from 103 HIV-2-infected and 56 HIV-1-infected patients using Bayesian Evolutionary Analysis by Sampling Trees (BEAST), a relaxed molecular clock and a Bayesian skyline coalescent model.
Bayesian skyline plots showed a strong increase in the 1990s of the HIV-1 effective population size (Ne) in the same period that the Ne of HIV-2 came into a plateau phase. The population dynamics of both viruses were remarkably similar following initial introduction. Incident infections were found more often in HIV-2 transmission clusters, with 55-58% of all individuals contributing to ongoing transmission. Some phylogenetically linked sexual partners had discordant viral loads (undetectable vs. detectable), suggesting host factors dictate the risk of disease progression in HIV-2. Multiple HIV-2 introductions into the cohort are evident, but ongoing transmission has occurred predominantly within the community.
Comparison of HIV-1 and HIV-2 phylodynamics in the same community suggests both viruses followed similar growth patterns following introduction, and is consistent with the hypothesis that HIV-1 may have played a role in the decline of HIV-2 via competitive exclusion. The source of ongoing HIV-2 transmission in the cohort appears to be new HIV-2 cases, rather than the pool of older infections established during the early growth of HIV-2.
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