Trends in HCV prevalence, risk factors and distribution of viral genotypes in injecting drug users: findings from two cross-sectional studies.

In the last decade, a declining prevalence of HCV infection has been described in injecting drug users (IDUs) in different countries. This study is the first to assess temporal trends in drug-injecting patterns, HCV infection rates and viral genotype distribution in 770 Brazilian IDUs, recruited by two cross-sectional studies (1994-1997 and 1999-2001). A substantial decline in the prevalence of HCV infection was found over the years (75% in 1994 vs. 20.6% in 2001, P<0.001) that may be a consequence of the significant reduction in the overall frequencies of drug injection and needle-sharing, as well as the participation of IDUs in initiatives aimed at reducing drug-related harm. No trend was found in terms of viral genotype distribution. Despite the favourable scenario, preventive measures must be maintained, especially in vulnerable subgroups such as young or new injectors, where risky behaviours through direct and indirect sharing practices remain common.

Dynamic linear model and SARIMA: a comparison of their forecasting performance in epidemiology.

One goal of a public health surveillance system is to provide a reliable forecast of epidemiological time series. This paper describes a study that used data collected through a national public health surveillance system in the United States to evaluate and compare the performances of a seasonal autoregressive integrated moving average (SARIMA) and a dynamic linear model (DLM) for estimating case occurrence of two notifiable diseases. The comparison uses reported cases of malaria and hepatitis A from January 1980 to June 1995 for the United States. The residuals for both predictor models show that they were adequate tools for use in epidemiological surveillance. Qualitative aspects were considered for both models to improve the comparison of their usefulness in public health. Our comparison found that the two forecasting modelling techniques (SARIMA and DLM) are comparable when long historical data are available (at least 52 reporting periods). However, the DLM approach has some advantages, such as being more easily applied to different types of time series and not requiring a new cycle of identification and modelling when new data become available.

Retrovirus infections in a sample of injecting drug users in Rio de Janeiro City, Brazil: prevalence of HIV-1 subtypes, and co-infection with HTLV-I/II.

BACKGROUND: Retrovirus infections among injecting drug users (IDUs), a core at-risk population for both HIV-1 and HTLV-I/II infections in Brazil, were assessed within an ongoing cooperative research. OBJECTIVE: The study assessed the seroprevalences of HIV-1 and HTLV-I/II infections, as well as the prevalence of HIV-1 subtypes in a sample of IDUs from Rio de Janeiro, Brazil. An attempt to evaluate HIV incidence was carried out using a dual 'sensitive/less sensitive' testing strategy. STUDY DESIGN: Cross-sectional evaluation of 175 IDUs. Serostatus for HIV-1 and HTLV-I/II were established by enzyme-linked immunosorbent assays, and confirmed by western blot. The dual testing strategy aimed to estimate HIV-1 incidence rates. Differentiation between HTLV-I and -II was performed by western blot. DNA samples were polymerase chain reaction amplified by a nested protocol, and HIV-1 subtyping was determined by heteroduplex mobility assay. RESULTS: Forty-six and 29 samples were found to be, respectively, positive for HIV-1 and HTLV-I/II, 15 of them co-infected by both viruses. Among HTLV-I/II-infected patients, 75.9% were infected by HTLV-I. Thirty-one HIV samples were identified as B subtype, with seven of them showing the typical "Brazilian B" pattern in the gp120 V3 loop, and ten were identified as F subtype. The use of less sensitive assays for HIV infection wrongly identified a deeply immunocompromised patient as an incident case. CONCLUSION: Moderately high seroprevalences were found for both HIV-1 and HTLV-I/II infections, HIV-1/HTLV-I co-infections being of special concern. A non-statistically significant higher prevalence of F subtype was observed, when compared with the distribution of F/B subtypes among Brazilian patients from other exposure categories. No recent HIV-1 infections were detected, but a limitation of the "sensitive/less-sensitive" testing strategy was made evident.

Prevalence and risk factors for HBV, HCV and HDV infections among injecting drug users from Rio de Janeiro, Brazil

Viral hepatitis constitutes a major health issue, with high prevalence among injecting drug users (IDUs). The present study assessed the prevalence and risk determinants for hepatitis B, C and D viruses (HBV, HCV and HDV) infections among 102 IDUs from Rio de Janeiro, Brazil. Serological markers and HCV-RNA were detected by enzyme immunoassay and nested PCR, respectively. HCV genotyping was determined by restriction fragment length polymorphism analysis (RFLP). HBsAg, anti-HBc and anti-HBs were found in 7.8, 55.8 and 24.7 percent of IDUs, respectively. In the final logistic regression, HBV infection was independently associated with male homosexual intercourse within the last 5 years (odds ratio (OR) 3.1; 95 percent confidence interval (CI) 1.1-8.8). No subject presented anti-delta (anti-HD). Anti-HCV was detected in 69.6 percent of subjects, and was found to be independently associated with needle sharing in the last 6 months (OR 3.4; 95 percent CI 1.3-9.2) and with longer duration of iv drug use (OR 3.1; 95 percent CI 1.1-8.7). These data demonstrate that this population is at high risk for both HBV and HCV infection. Among IDUs from Rio de Janeiro, unprotected sexual intercourse seems to be more closely associated with HBV infection, whereas HCV is positively correlated with high risk injecting behavior. Comprehensive public health interventions targeting this population and their sexual partners must be encouraged

Prevalence and risk factors for HBV, HCV and HDV infections among injecting drug users from Rio de Janeiro, Brazil.

Viral hepatitis constitutes a major health issue, with high prevalence among injecting drug users (IDUs). The present study assessed the prevalence and risk determinants for hepatitis B, C and D viruses (HBV, HCV and HDV) infections among 102 IDUs from Rio de Janeiro, Brazil. Serological markers and HCV-RNA were detected by enzyme immunoassay and nested PCR, respectively. HCV genotyping was determined by restriction fragment length polymorphism analysis (RFLP). HBsAg, anti-HBc and anti-HBs were found in 7.8, 55.8 and 24. 7% of IDUs, respectively. In the final logistic regression, HBV infection was independently associated with male homosexual intercourse within the last 5 years (odds ratio (OR) 3.1; 95% confidence interval (CI) 1.1-8.8). No subject presented anti-delta (anti-HD). Anti-HCV was detected in 69.6% of subjects, and was found to be independently associated with needle sharing in the last 6 months (OR 3.4; 95% CI 1.3-9.2) and with longer duration of iv drug use (OR 3.1; 95% CI 1.1-8.7). These data demonstrate that this population is at high risk for both HBV and HCV infection. Among IDUs from Rio de Janeiro, unprotected sexual intercourse seems to be more closely associated with HBV infection, whereas HCV is positively correlated with high risk injecting behavior. Comprehensive public health interventions targeting this population and their sexual partners must be encouraged.

Anti-HIV-1 seroreactivity and HIV transmission route[R1]. The HEC/FIOCRUZ AIDS Clinical Research Group.

BACKGROUND: Antibody binding assays carried out by our group have consistently indicated a higher reactivity of sera from male HIV-1 infected individuals. This study was carried out in order to analyze the importance of gender, route of transmission, disease progression and HIV-1 genotype in seroreactivity assays. STUDY DESIGN: Specificity of antibody binding was studied in plasma of 247 HIV-1 seropositive individuals belonging to patient groups of pregnant women, injecting drug users (IDUs) and recent seroconvertors, resident in Rio de Janeiro, RJ. Recognition of synthetic peptides corresponding to antigenically important epitopes in the envelope of HIV-1 (gp41 immunodominant epitope, V3 loop, V2 loop and gp41 735-752 epitope) was determined. RESULTS: The immunodominant gp41 peptide (amino acids 594-613, HIV-1 MN sequence) was recognized by 85% of all plasma tested. Reactivity with the gp41 735-752 peptide and gp120 V2 loop peptides was low but quite variable, being generally more often specific to a Brazilian V2 peptide used than to the HIV-1 MN derived V2 peptide. The overall recognition of the different V3 peptides tested varied from 41 to 76%. Patients with more advanced disease showed a more frequent reactivity with the peptides studied than did asymptomatic patients. Statistically significant differences in peptide recognition were observed by multiple logistic analyses comparing plasma derived from individuals infected by blood or sexual HIV transmission, adjusting for disease progression and gender. Plasma from individuals infected by sexual transmission showed lower peptide recognition than did plasma from individuals infected through HIV positive blood. Association attempts between seroreactivity and genotype indicated that plasma derived from patients infected with HIV-1 of the F subtype showed highest recognition of heterologous V3 peptides, as well as a slightly more frequent recognition of the non-V3 peptides tested. Recognition of homologous peptides was generally higher than recognition of heterologous peptides. Differences were most pronounced between the prototypical HIV-1 B subtype and the Brazilian B" variant of this subtype but almost non-existent between the HIV-1 B and F subtypes. CONCLUSIONS: Individual gender was shown to be a confounder when investigating the relationships of peptide reaction to HIV-1 route of transmission through multivariate statistical methods: patients infected by blood transmission (IDU) present higher frequency of peptide recognition than individuals infected by sexual HIV-1 transmission. Plasma from individuals infected with the B" variant (GWG) of B subtype HIV-1 showed lower heterologous peptide recognition than that from HIV-1 B (GPG) or F infected individuals.

HIV specific humoral immune response in Rio de Janeiro, Brazil. The HEC/Fiocruz AIDS Clinical Research Group.

Efforts to characterize HIV-1 polymorphism and anti-HIV immune response are being made in areas where anti-HIV/AIDS vaccines are to be employed. Anti-HIV-1 humoral immune response is being studied in infected individuals residents in Rio de Janeiro, in distinct cohorts involving recent seroconvertors, pregnant women or intravenous drug users (IDU). Comparative analyses of specificity of antibody response towards epitopes important for anti-HIV-1 immune response indicate quantitative differences between cohorts, with an exceptionally strong response in IDUs and weakest response in pregnant women. However, a comparative analysis between pregnant women cohorts from Rio de Janeiro and Rio Grande do Sul indicated an even lower response (with exception of the anti-V3-C clade peptide recognition) for the southern cohort. Studies analysing the immune function of the humoral response indicate a quite elevated occurrence of antibodies capable for neutralizing heterologous primary HIV-1 isolates from Rio de Janeiro. Attempts to correlate seroreactivity with HIV-1 neutralization with respect to HIV-1 polymorphism were not very successful: while the Brazilian B clade B " variant could be recognized by binding assays, no significant distinction of HIV-1 clades/variants was observed in viral neutralization assays.

HIV specific humoral immune response in Rio de Janeiro, Brazil

Efforts to characterize HIV-1 polymorphism and anti-HIV immune response are being made in areas where anti-HIV/AIDS vaccines are to be employed. Anti-HIV-1 humoral immune response is being studied in infected individuals resident in Rio de Janeiro, in distinct cohorts involving recent seroconvertors, pregnant women or intravenous drug users (IDU). Comparative analysis of specificity of antibody response towards epitopes important for anti-HIV-1 immune response indicate quantitative differences between cohorts, with an exceptionally strong response in IDUs and weakest response in pregnant women. However, a comparative analysis between pregnant women cohorts from Rio de Janeiro and Rio Grande do Sul indicated an even lower response (with exception of the anti-V3-C clade peptide recognition) for the southern cohort. Studied analysing the immune function of the humoral response indicate a quite elevated occurrence of antibodies capable of neutralizing heterologous primary HIV-1 isolates from Rio de Janeiro. Attempts to correlate seroreactivity with HIV-1 neutralization with respect to HIV-1 polymorphism were not very successfull: while the Brazilian B clade B" variant could be recognized by binding assays, no significant distinction of HIV-1 clades/variants was observed in viral neutralization assays.

Risk behavior and HIV seroprevalence among injecting drug users in Rio de Janeiro, Brazil.

OBJECTIVE: To characterize HIV seroprevalence and risk behavior among injecting drug users (IDUs) in Rio de Janeiro, Brazil, between 1990 and 1996. DESIGN: We report data from three separate cross-sectional samples of IDUs in Rio de Janeiro: the World Health Organization (WHO) sample (n = 479), the Proviva sample (n = 138) and the Brasil sample (n = 110). These data provide the most comprehensive view available, to date, of this understudied population in Rio. METHODS: Demographic characteristics, HIV/AIDS risk behavior and HIV seroprevalence were compared across the three samples and combined analyses were performed to determine the factors associated with injecting risk behavior, sexual risk behavior and HIV seropositivity. RESULTS: The overall HIV seroprevalence among IDUs was 25%. Two encouraging findings of the present analysis were the lower levels of needle-sharing among participants recruited in the latest years (1995-1996) and the lower HIV seroprevalence in the Proviva sample composed mainly of less educated, poorer IDUs living in deprived neighborhoods. No trends toward safer behavior were found for sexual risk, younger age being the principal factor associated with high risk. CONCLUSIONS: Levels of needle-sharing and sexual risk among IDUs in Rio remain high, demonstrating the urgent need to increase the limited preventive measures undertaken so far. Seroprevalence levels for HIV remain significantly lower in the most deprived sample, arguing for the fundamental importance of prompt and effective prevention strategies to keep infection rates from rising among the poorest and largest strata of Rio's IDUs.

Risk factors for HIV-1 seroprevalence among drug injectors in the cocaine-using environment of Rio de Janeiro.

To determine risk factors for HIV-1 among drug injectors in Rio de Janeiro, where cocaine is the dominant drug of injection, subjects were recruited using the criteria and interview instrument of the World Health Organization's Cross-National Study of HIV infection and risk behaviour in injecting drug users. HIV antibody test results were derived both from serum tests and from self-reports of previous tests (documented evidence of self-reported seropositivity was required). The analytical sample consists of 123 subjects, recruited both at drug abuse treatment sites and at street locations. Of 27 subjects with both serological and self-reported antibody status data, 20 reported previous negative tests; of these three had positive sera and may have seroconverted. Seven subjects reporting prior positive serostatus all tested positive. For the 123 subjects, seroprevalence was 34%. Independent significant risk factors in multivariate logistic regression with backwards elimination are: years of injection greater than 5; being a male who has had sex with men in the previous 5 years; and not having taken deliberate steps to protect oneself against AIDS. These findings indicate that homosexual/bisexual male drug injectors may be a bridge group through which HIV is entering drug-injecting networks in Rio de Janeiro. Efforts by drug injectors to reduce their risk of infection seem to have protective effects. This underscores the importance of HIV prevention efforts aimed at drug injectors.

[The hidden face of AIDS in Brazil]. / O Não-dito da AIDS.

The authors report on the evolution of the AIDS epidemic in Brazil from the point of view of the construction of social representations about "risk groups" involved in the spread of the disease. They emphasize the need to demystify the immediate correlation between AIDS and homosexual transmission. They highlight the role of intravenous drug users and of heterosexual transmission in new AIDS cases in Brazil - groups and behaviours that are not included in the priorities of local health authorities.

HIV infection and AIDS among drug injectors at Rio de Janeiro: perspectives and unanswered questions.

Data from various countries show considerable variation in the rate of spread of the human immunodeficiency virus (HIV) among drug injectors. Although further research is needed to predict the rate of increase of seroprevalence at Rio de Janeiro, preliminary data confirm the presence of the virus, with a seroprevalence of about 33 per cent in 1990. Issues arising from research into the probable determinants of viral spread among the thousands of drug injectors in the city are outlined in the present paper. Even before the research is completed, however, it is clear that interventions are needed to reduce further viral transmission both among drug injectors and from them to their sexual partners and offspring. Efforts should be made to prevent the population at risk from initiating the practice of drug injection, and to promote a major expansion in drug abuse treatment facilities. Drug injectors should also be encouraged to reduce the risk of their becoming infected or passing on the virus to others, through educational outreach, through the distribution of supplies that facilitate risk reduction (bleach, syringes, condoms), and through innovative approaches to behaviour change.

PIP: Data from various countries show considerable variation in the rate and extent of HIV spread among IV drug users (IVDU). More than 11,000 people have been diagnosed as having AIDS in Brazil, of whom 1700 were in Rio de Janeiro. 82 of these 1700 people were heterosexual IVDUs and 16 were homosexual or bisexual IVDUs. Although additional research is needed to predict the level and rate of increase of HIV seroprevalence in Rio de Janeiro, preliminary data suggest that as many as 33% of IVDUs in 1990 may have been HIV-seropositive. Such data clearly warrant interventions to reduce HIV transmission within this population and from them to their sex partners and offspring. This paper outlines issues arising from research into the probable determinants of viral spread among the thousands of drug injectors in the city. Efforts need to be made to prevent the population at risk from beginning to use injecting drugs and to promote a major expansion in drug abuse treatment facilities. Drug injectors should also be encouraged to reduce the risk of their becoming infected or passing the virus to others. Approaches could include educational outreach; the distribution of supplies which facilitate risk reduction such as bleach, syringes, and condoms; and innovative approaches to behavior change.