RESUMOOs vírus linfotrópicos de células T humanas, quando integrados ao genoma da célula hospedeira, provírus, têm como marcador de replicação seu DNA proviral. A carga proviral parece ser um importante fator no desenvolvimento de patologias associadas a estes retrovírus. Neste estudo foi desenvolvida uma metodologia para quantificação absoluta da carga proviral dos HTLV-1 e HTLV-2 através da PCR em tempo real. Cinqüenta e três amostras de doadores de sangue com teste de ELISA reagente foram submetidas à metodologia, que utilizou o sistema TaqMan ® para três seqüências alvo: HTLV-1, HTLV-2 e albumina. A quantificação proviral absoluta foi determinada através da proporção relativa entre o genoma do HTLV e o genoma da célula hospedeira, levando em consideração o número de leucócitos. O método apresentado é sensível (215 cópias/mL), prático e simples para quantificação proviral, além de eficiente e adequado para confirmação e discriminação da infecção pelos tipos virais. Palavras-chaves: HTLV. PCR quantitativa em tempo real. Carga proviral do HTLV. ABSTRACTWhen the human T cell lymphotropic virus (HTLV) is integrated with the host cell genome (provirus), its proviral DNA is a replication marker. Proviral load appears to be an important factor in the development of diseases related to these retroviruses. In this study, a methodology for absolute quantification of the HTLV-1 and HTLV-2 proviral load using real-time PCR was developed. Fifty-three blood donor samples with positive ELISA test result were subjected to this methodology, which utilized the TaqMan ® system for three target sequences: HTLV-1, HTLV-2 and albumin. The absolute proviral load was quantified using the relative ratio between the HTLV genome and the host cell genome, taking into consideration the white blood cell count. The method presented is sensitive (215 copies/ml), practical and simple for proviral quantification, and is efficient and appropriate for confirming and discriminating infections according to viral type. Key-words: HTLV. Quantitative real-time PCR. HTLV proviral load. Os vírus linfotrópicos de células T humanas (HTLV-1

Introduction: Illicit drug users (DUs) are vulnerable to hepatitis C virus (HCV) infection. The shared use of illicit drugs is the main method of HCV transmission. Methods: A cross-sectional study was conducted in Breves, in northern Brazil. We surveyed 187 DUs to determine the prevalence of and factors associated with HCV infection. Results: The prevalence of anti-HCV antibodies was 36.9%, and the prevalence of hepatitis C virus-ribonucleic acid (HCV-RNA) was 31%. Hepatitis C virus infection was associated with tattoos, intravenous drug use, shared use of equipment for drug use, drug use for longer than 3 years, and daily drug use. Conclusions: Strategies for preventing and controlling HCV transmission should be implemented among DUs.Keywords: Hepatitis C virus. Illicit drug users. Northern Brazil.Currently, the sharing of drug paraphernalia is the main transmission method for hepatitis C virus (HCV) worldwide. It is estimated that more than 60% of new HCV infection cases recorded each year are related to the use of illicit drugs, particularly injected drugs 1,2 . In Brazil, epidemiological studies of HCV infection in illicit drug users are still rare. The prevalence of HCV infection in illicit drug users sampled in metropolitan areas in the Northeast, Midwest, South and Southeast regions of Brazil ranged from 5% to 36% 3-7 . There are frequent reports of clinical cases of hepatitis or pathologies associated with HCV infection in other population groups in northern Brazil [8][9][10][11] . It is known that most illicit drug users in Pará do not consume injected drugs and are infected with HCV genotype 1 10,11 . This study estimated the prevalence of HCV infection and assessed the factors associated with HCV infection in illicit drug users in the municipality of Breves, State of Pará, northern Brazil.This cross-sectional study of a non-probabilistic convenience sample was based on information and biological samples provided by illicit drug users in an area of intense illicit drug use located in Breves (01° 40' 55" S 50° 28' 48" O), Archipelago of Marajó, Pará, northern Brazil. Illicit drug users in areas of intense drug consumption were sampled using the snowball technique 11 . Individuals were eligible for the study if they were older than 17 years of age and agreed to answer a specifi c questionnaire and have a blood sample taken and tested for molecular and serologic markers in the period from August to All samples were tested for HCV antibodies and hepatitis C virus-ribonucleic acid (HCV-RNA). Anti-HCV antibodies were tested by enzyme immunoassay (EIA; Murex anti-HCV 4.0, Murex Biotech). HCV RNA was detected by real-time polymerase chain reaction (PCR) using 67 base pairs of the 5' untranslated region (UTR), as described elsewhere 9 . Confi dence intervals (CIs) were determined for infection prevalence estimates. Simple and multiple logistic regressions were calculated to assess the independent effects of variables 12 . The fi t of the fi nal model was assessed using the Hosmer-Lemeshow goodness-of-f...

This study evaluated epidemiological factors for HCV infection associated with sharing perforating and cutting instruments among candidates for blood donation (CBD) in the city of Belém, Pará, Brazilian Amazon. Two definitions of HCV infection cases were used: anti-HCV positivity shown by EIA, and HCV-RNA detection by PCR. Infected and uninfected CBD completed a questionnaire about possible risk factors associated with sharing perforating and cutting instruments. The information was evaluated using simple and multiple logistic regressions. Between May and November 2010, 146 (1.1%) persons with anti-HCV antibodies and 106 (0.8%) with HCV-RNA were detected among 13,772 CBD in Belém. Risk factors associated with HCV infection based on the EIA (model 1) and PCR (model 2) results were: use of needles and syringes sterilized at home; shared use of razors at home, sharing of disposable razors in barbershops, beauty salons etc.; and sharing manicure and pedicure material. The models of HCV infection associated with sharing perforating and cutting instruments should be taken into account by local and regional health authorities and by those of other countries with similar cultural practices, in order to provide useful information to guide political and public strategies to control HCV transmission.