Seroprevalence of hepatitis B and C in the Western Brazilian Amazon region (Rio Branco, Acre): a pilot study carried out during a hepatitis B vaccination program

In 1999, on the occasion of the application of the first vaccine dose during the state vaccination campaign against hepatitis B virus (HBV), 390 individuals from the town of Rio Branco, Acre, aged two or more years were selected for the determination of the seroprevalence of HBV and HCV. HBV markers (HBsAg, anti-HBs, and anti-HBc IgG) were determined on this occasion and anti-HBs antibodies were also assessed 30 days after the third vaccine dose. At the time of vaccination, 39 percent of the individuals were still susceptible to HBV, while 61 percent presented serologic evidence of previous HBV contact or previous vaccination. The individuals with previous HBV contact were significantly older (p<0.001) than those without HBV markers. Of the 192 individuals who returned for reexamination, 30 days after the third dose, 158 (82.3 percent) had received three vaccine doses, and only 60 (31.2 percent) belonged to the group without HBV markers. In these individuals, the seroconversion rate after the third dose was 92 percent (55/60). In conclusion, we found considerable HBV in this population, indicating the need for pursuing the immunization programs. We also found high rates of vaccination coverage in the Western Brazilian Amazon region.

Comparative study of Hepatitis C virus genotypes 1 and 3 in Salvador, Bahia

Hepatitis C virus displays a high degree of genetic mutation, with considerable heterogeneity, motivating clinical and biomolecular investigations. It is necessary to understand the effects of genotypes on the course of the disease, as well as their peculiarities at the regional level. OBJECTIVE: The study objective was to compare epidemiological, biochemical and histological aspects of hepatitis C virus genotypes 1 and 3 in Salvador, Bahia. STUDY DESIGN: Data were collected retrospectively from outpatient medical records. MATERIALS AND METHODS: 127 patients with positive anti-HCV results were selected, based on detectable RNA-HCV (RT-PCR) of genotypes 1a, 1b and 3a. RESULTS: Thirty-nine (30.7 percent) individuals were infected by subtype 1a, 45 (35.4 percent) by subtype 1b and 43 (33.9 percent) by subtype 3a. Most (73.2 percent) patients were male, with an average age of 47.8 years. The subtype 1b-infected patients had the highest average age (512 ±11.17; P=0.09). The use of illicit injected drugs was more frequent among subtype 3a infected individuals when compared with genotype 1 (6/43; 14 percent and 3/84; 3.6 percent, respectively; P=0,06). No significant differences were found for other epidemiological characteristics. Average values for GT, AST, ALT and ferritin did not differ between the groups (64, 78, 109, 276, respectively). Thyroid dysfunction occurred in 7/30 (23.3 percent) of those infected by genotype 3 (P=0.05). Cryoglobulinemia was also more frequent in this group (5/13, 38 percent, P=0.02). Most patients presented limited necro-inflammatory activity, stages 2 and 3 by the METAVIR Classification. In some cases, dissociation was noticed between inflammatory activity and fibrosis. No significant differences were found in the histopathological findings of the various genotypes. Younger patients had a significantly smaller degree of necrosis in stomatocytosis (P=0.032) and fibrosis (P=0.012). Intense parenchymatous activity and lymphoid follicles were more frequent among alcohol consumers (P=0.06 and P=0.04, respectively). CONCLUSIONS: In Bahia, genotype 3 dissemination seems to be associated with illicit drug use. The disease evolution depends on a function of complex interactions between virus and host. Age and alcohol consumption stand out as important variables in the development of cirrhosis.