Epidemiological aspects of hepatitis B and D virus infection in the northern region of Amazonas, Brazil

Abstract

The State of Amazonas in the Brazilian Amazon region is an area of high prevalence of hepatitis B and D virus (HBV and HDV) infection. The aim of this study was to identify epidemiological patterns and risk factors of HBV and HDV infections in Barcelos, in the basin of the Negro river. A random sample (798 in all) of the total population in the urban area and in 2 rural villages was surveyed. A standardized questionnaire was used and blood samples were tested by enzyme-linked immunosorbent assay: 1.63% had hepatitis B surface antigen, 12.9% had anti-hepatitis B surface antibody and 21.4% had anti-hepatitis B core antigen. The overall prevalence of HBV infection was 24.6%. Anti-hepatitis D was present in 5 subjects, all of them non-natives, and hepatitis B e antigen in 2. A positive association between history of dental treatment with an unqualified dental surgeon was found (P < 0.05). These results suggest a low prevalence of HVB and HDV infection, in contrast with other parts of the Amazon area.

Seroprevalence of viral hepatitis in riverine communities from the Western Region of the Brazilian Amazon Basin

“…Eighteen (5.2%) individuals were positive for HBsAg, among those 66.7% were found to be anti-Delta positive. Our results are consistent with other studies that showed that HAV, HBV and HDV are widespread in the Amazon jungle (Arboleta et al 1995, Azevedo et al 1996, Coimbra Junior et al 1996.…”

“…Based on the world endemicity categorization of HBV infection (Margolis et al 1991), the HBsAg prevalence of 5.2% characterizes the Purus and Acre rivers as an area of high prevalence of HBV infection. The rates of HBV prevalence observed in this region were not different from those reported for the western part of the Amazon Basin, which has the highest HBV infection prevalence in South America (Fay 1990, Arboleta et al 1995. The prevalence of anti-HBc was already high (27.3%) in the youngest age group (0-10 years) and then sharply increased to 50% and 70.8% at the 11-20 and 21-30 age groups, respectively.…”

Epidemiology and Molecular Characterization of Hepatitis B Virus Infection in Isolated Villages in the Western Brazilian Amazon

“…25,26,[35][36][37][38] The presence of HBsAg, the most commonly used marker to determine present infection, is an important tool for evaluating the mechanisms of transmission dynamics, its principal actors, and for identifying the population at potential risk of chronic liver disease. HBsAg = hepatitis B surface antigen; N = number of subjects; N+ = number of positive subjects; F = female; M = male; 95% CI = 95% confidence interval; *AOR = adjusted odds ratio for the following variables: age, village, past family history of clinical Malaria, vaccination against HBV, and presence of HBeAg-reactive in the Family; P value = statistical significance.…”

Hepatite D

“…O HBsAg do invólucro do VHD constitui-se de três tipos de proteínas. A primeira, codificada pelo gene S do HBV-DNA, a segunda pela sequência de 55 aminoácidos da região Pré S 2 e, a terceira, constituída de 108 -119 aminoácidos da região Pré S 1 21 e, em determinadas áreas da África 27 . O mesmo fator epidemiológico aplica-se aos grupos de alto risco para hepatite B, como os toxicômanos, os hemodializados e os politransfundidos 13 42 .…”

“…Na Amazônia brasileira, área de alta prevalência e incidência de malária, como também de alta densidade de mosquitos, observa-se nas calhas dos rios sabidamente malarígenos alta prevalência de infecção pelo VHB e VHD 15 , fato este não observado entre indivíduos residentes em calhas de rios não malarígenos 1 .…”