Characterization of hepatitis B virus infection in illicit drug users in the Marajó Archipelago, northern Brazil.

South America is considered to have a low prevalence of hepatitis B virus (HBV) infection, although areas with a relatively high prevalence have been identified in northern Brazil. Few epidemiological studies of populations at risk of HBV infection are available for this region. Given this, in the present study, we investigated the prevalence of HBV and the factors associated with infection among illicit drug users (DUs) in the Marajó Archipelago, northern Brazil. In this cross-sectional study, we collected samples and epidemiological information from DUs in 11 municipalities of the Marajó Archipelago. The diagnosis was established by ELISA and real-time PCR; and genotyping was done by multiplex real-time PCR. Statistical modeling was based on simple and multiple logistical regressions with the Hosmer-Lemeshow test. The mean age of the 466 DUs was 28.4 years, and most were male. The most-consumed illicit drugs were crack cocaine and marijuana. In all, 171 DUs were exposed to HBV, with genotypes A, D and F being identified. The factors associated with higher frequencies of HBV infection were (i) male gender, (ii) age above 35 years, (iii) anti-HIV positivity, (iv) tattoos, (v) the use of injected drugs, (vi) the use of illicit drugs for more than 3 years, (vii) sexual relations without protection, (viii) sexual relations with another DU, and (ix) more than 10 sexual partners in the past 24 months. In summary, this study provides important insights into the dynamics of HBV infection among DUs in the Marajó Archipelago. We hope that these findings will contribute to the development of strategies, actions and public health policies aimed at preventing and controlling this viral infection more effectively.

Epidemiological aspects of HCV infection in non-injecting drug users in the Brazilian state of Pará, eastern Amazon.

BACKGROUND: Currently, sharing of drug paraphernalia is the main form of HCV transmission worldwide. In South America, consistent findings indicate that shared sniffing equipment is an important factor in the spread of HCV among non-injecting drug users. Epidemiological data on the status of HCV infection in illicit drug users in the Amazon region are scarce, although reports of clinical cases of hepatitis or pathologies associated with HCV infection in other population groups are numerous. Thereby, this study investigated the prevalence, genotype frequency, and epidemiological factors associated with HCV infection in non-injecting drug users in the state of Pará, eastern Amazon. RESULTS: During 2008-2011, 300 non-injecting drug users attending drug-treatment centers participated in this study. Most non-injecting drug users were male (63.7%). The mean age was 32.5 years. The non-injecting drugs most consumed were: cannabis (15.6%), cocaine paste (21.3%), and oxi cocaine (25.7%). Tobacco (60.9%) and alcohol (79.4%) were also commonly consumed. One hundred six (35.1%; CI 95%: 29.8 - 41.1) non-injecting drug users presented anti-HCV antibodies by EIA. The HCV-RNA prevalence was 28.0% (95% CI: 20.6 - 35.8). Genotypes 1 (76.9%) and 3 (23.1%) of HCV have been identified. A multivariate analysis demonstrated that HCV infection was independently associated with the following factors: "age (≥ 35 years)", "tattoos", "use of a needle or syringe sterilized at home", "shared use of drug paraphernalia", "uses drugs for more than 5 years", and "use of drugs everyday". CONCLUSIONS: This study revealed a high prevalence of HCV infection in non-injecting drug users, and most infections are occasioned by genotype 1. Likely, HCV transmission is associated with the tattoos, the use of needle or syringe sterilized at home by people over the age of 35 years, and sharing, time and frequency of use of non-injecting drugs. These findings should serve as an incentive for the establishment of a program of Hepatitis C prevention and control by the local public-health authorities in order to develop effective policies and strategies for contain the spread of HCV infection.