The genetic characterization of dengue virus type 3 (DEN-3) strains isolated from autochthonous cases in the State of Rio de Janeiro, Brazil, in 2001 is presented. Restriction site-specific (RSS)-PCR performed on 22 strains classified the Brazilian DEN-3 viruses as subtype C, a subtype that contains viruses from Sri Lanka, India, Africa and recent isolates from Central America. Nucleic acid sequencing (positions 278 to 2550) of one DEN-3 strain confirmed the origin of these strains, since genotype III - classified by sequencing - and RSS-PCR subtype C are correlated. This genetic subtype has been associated with hemorrhagic dengue epidemics and the information provided here could be useful to implement appropriate prevention and control measures.

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.

Dois grupos de pacientes em tratamento hemodialítico foram avaliados quanto às respostas de anticorpos contra as proteínas não estrutural c100/3 (anti-c100/3) e estrutural core (anti-HCV core) do vírus da hepatite C (HCV). Quarenta e seis pacientes (Grupo 1) nunca apresentaram alterações dos níveis de alanina aminotransferase (ALT) durante o tratamento hemodialítico, ao passo que 52 pacientes (Grupo 2) têm ou já tiveram elevações desta enzima hepática. Em pacientes sem alterações bioquímicas evidentes (Grupo 1) foram encontradas prevalências de 32.6% e 41.3% para anti-c100/3 e anti-HCV core, respectivamente. No Grupo 2, estas prevalências foram de 71,15% e 86,5%. Um teste composto de peptídeos estruturais e não estruturais imobilizados separadamente e dispostos em bandas paralelas em fitas de nailon, foi usado como teste confirmatório. A infecção pelo HBV, avaliada pela presença de anticorpos anti-HBc foi observada em 39.8% dos pacientes; 6 eram portadores crônicos de HBsAg e 13 possuiam anti-HBs adquiridos naturalmente. O tempo de tratamento hemodialítico teve correlação com a positividade para anti-HCV. A prevalência de 96,7% (Grupo 2) foi encontrada em pacientes que tiveram mais de 5 anos de tratamento. Nossos resultados sugerem que o anti-HCV core é um marcador mais preciso para detectar a infecção pelo HCV do que o anti-c100/3. Apesar dos riscos associados com a duração do tratamento e transfusões sanguíneas, uma significante disseminação não transfusional do HCV parece ocorrer dentro da unidade. A identificação de pacientes infectantes por métodos sensíveis como a detecção do genoma viral deverá auxiliar no controle da transmissão do HCV na unidade em estudo.

Two groups of patients undergoing hemodialysis (HD) maintenance were evaluated for their antibody response to non-structural c100/3 protein and structural core protein of hepatitis C virus (HCV). Forty-six patients (Group 1) never presented liver abnormalities during HD treatment, while 52 patients (Group 2) had either current or prior liver enzyme elevations. Prevalence rates of 32.6% and 41.3% were found for anti-c100/3 and anti-HCV core antibodies, respectively, in patients with silent infections (Group 1). The rate of anti-c100/3 in patients of Group 2 was 71.15% and reached 86.5% for anti-HCV core antibodies. The recognition of anti-c100/3 and anti-core antibodies was significantly higher in Group 2 than in Group 1. A line immunoassay composed of structural and non-structural peptides was used as a confirmation assay. HBV infection, measured by the presence of anti-HBc antibodies, was observed in 39.8% of the patients. Six were HBsAg chronic carriers and 13 had naturally acquired anti-HBs antibodies. The duration of HD treatment was correlated with anti-HCV positivity. A high prevalence of 96.7% (Group 2) was found in patients who underwent more than 5 years of treatment. Our results suggest that anti-HCV core ELISA is more accurate for detecting HCV infection than anti-c100/3. Although the risk associated with the duration of HD treatment and blood transfusion was high, additional factors such as a significant non-transfusional spread of HCV seems to play a role as well. The identification of infective patients by more sensitive methods for HCV genome detection should help to control the transmission of HCV in the unit under study.

Um estudo soroepidemiológico prévio na zona rural de Vargem Alta (ES) - Sudeste do Brasil, mostrou uma predominância de até 9% do antígeno de superfície da Hepatite B (HBsAg). Foram selecionadas 100 crianças com faixa etária entre 1 e 5 anos de idade, as quais foram imunizadas com vacina contra Hepatite B -DNA recombinante (Smith-Kline,20 mcg) nos meses 0,1 e 6. Foram coletadas amostras de sangue antes da primeira dose da vacina (mês 0) para confirmação dos susceptíveis, e nos meses 1,3,6 e 8 após a vacinação para avaliação da resposta vacinai. Os resultados mostraram que 79 e 88% das crianças apresentaram soroconversão dois e cinco meses após a segunda dose respectivamente, atingindo 97% de soroconversão, após a 3a.dose. Os níveis de anti-HBs foram calculados em miliunidades internacionais/ml (mUI/ml), demonstrando um considerável aumento dos níveis de anticorpos protetores após a 3a. dose. Os resultados demonstraram uma boa imunogenicidade da vacina de DNA recombinante contra hepatite B, quando administradas em crianças de áreas endêmicas.

A previous seroepidemiological study in the rural zone of Vargem Alta (ES) SouthEast of Brazil, showed a prevalence of up to 9% of hepatitis B surface antigen (HBsAg) in some areas. One hundred susceptible children aging 1 to 5 years old were selected and immunized with a recombinant DNA hepatitis B vaccine (Smith-Kline 20 mcg) using the 0-1-6 months vaccination schedule. Blood samples were collected at the time of the first vaccine dose (month 0) in order to confirm susceptible individuals and 1,3,6 and 8 months after the first dose , to evaluate the antibody response. Our results showed that two and five months after the second dose, 79% and 88% of children seroconverted respectively, reaching 97% after the third dose. The levels of anti-HBs were calculated in milli International Units/ml (mIU/ml) and demonstrated the markedly increase of protective levels of antibodies after the third dose. These data showed a good immunogenicity of the DNA recombinant hepatitis B vaccine when administered in children of endemic areas.