High seroprevalence of hepatitis B and C markers in the upper Madeira River region, Porto Velho, Rondônia State, Brazil

Abstract

A seroprevalence study on the serologic markers of hepatitis types B and C on the inhabitants of the upper Madeira River, between the communities of Santo Antonio and Abunã, in the Municipality of Porto Velho, Rondônia State, was conducted. This locality will be flooded by two new hydropower plants yet to be built in the Madeira River. Local population was estimated in 5 thousand individuals, according to Instituto Brasileiro de Geografia e Estatística's (Brazilian Institute of Geography and Statistics) census. A sample of 10% of the population was randomly selected. Five milliliters of peripheral venous blood were collected in Vacutainer^® dry tubes, and the serum samples were maintained in a freezer at -20° C. ELISA serological tests (DiaSorin, Inc.) were performed according to the manufacturer's methodology for the following viral markers: total Anti-HBc, HBsAg, Anti-HBs and Anti-HCV After the processing of 431 samples, the results were: 192 (44.5%) were positive for total Anti-HBc, 29 (6.7%) were positive for HBsAg, 230 (53.4%) were positive for Anti-HBs, and 32 (7.4%) were positive for Anti-HCV We concluded that this region presented an intermediate and a high prevalence rate for hepatitis B and C, respectively, according to the World Health Organization. The high prevalence (more than 50%) of individuals immune to hepatitis B leads us to the conclusion that in the next decades problems related to that type of hepatitis tend to decrease, whereas the incidence of hepatitis C will probably increase. Migration of thousands of new inhabitants drawn by the implementation of the new hydropower plants in this region has the potential of worsening the public health issues related to these viral hepatitis infections.