Epidemiology of hepatitis A and E virus infection in Brazil.

This review has the objective to discuss the epidemiological aspects of the enterically transmitted hepatitis A and E in Brazil. The prevalence of hepatitis A varies greatly in different Brazilian regions, from 56% in South and Southeast to 93% in North region (Manaus, Amazon). Such differences are also found in different socioeconomic levels among age groups. A significantly higher prevalence was seen in the low socioeconomic group between 1-30 years. This difference is most striking in the first 10 years of age (23.5% vs 60.0%, high/middle vs low, respectively). Despite the improvements in sanitary conditions, hepatitis A is still endemic and outbreaks may occur. As an increasing proportion of the population is becoming susceptible to hepatitis A virus infection and as adult individuals may present more severe forms of the disease, the authors conclude that the implement of hepatitis A vaccination should be considered. Some Brazilian data have shown that the genotype found in our country were IA and IB. Isolates from this study were closely related genetically (or even identical) to isolates originating in other South American countries and overseas, providing firm evidence for epidemiological links between persons who travel to endemic areas. In spite of favorable environmental conditions, outbreaks of hepatitis E have never been reported in Brazil. Nevertheless, reports have demonstrated the evidence of anti-hepatitis E virus antibodies in some Brazilian regions. The seroprevalence of IgG anti-hepatitis E virus among normal populations shows positivities of 6.1% in gold-miners, 3.3% in general population, 2.0-7.5% in blood donors, 1.0% in pregnant women, and 4.5% in children, with no differences among regions. In populations at risk the prevalence of anti-hepatits E virus varies greatly. Among patients with acute non-A, non-B, non-C hepatitis 2.1% was detected in the Southeast to 29% in the Northeast, in 10.6% of acute non-A, non-B, non-C hepatitis relatives in the Amazon basin, in 12% of acute sporadic non-A non-B hepatitis patients in the Northeast, a co-infection with acute hepatitis A in 25 to 38% in the Northeast, in 14 to 18% among prostitutes and women considered at risk for human immunodeficiency virus in the Southeast, and in 12% of the intravenous drug users in the Southeast.