Prevalence of hepatitis A virus infection: the paradoxical example of isolated communities in the western Brazilian Amazon region

Prevalência da infecção pelo vírus da hepatite A: o exemplo paradoxal de comunidades isoladas na região Amazônica Ocidental Brasileira

Wornei Silva Miranda Braga Fabiane Giovanella Borges Gildo Maia Barros Júnior Ana Cristina de Souza Martinho Ivo Seixas Rodrigues Eliete Pereira de Azevedo Gustavo Henrique Nolasco Grimmer Davis Manoel Bezerra de Queiroz Simone Helena Derzi dos Santos Thiago Vitoriano Barbosa Márcia da Costa Castilho About the authors

This study evaluated the prevalence of hepatitis A virus infection in the rural area of Lábrea, in the western Brazilian Amazon region. Communities and households were selected randomly. Serum samples were analyzed by means of the immunoenzymatic method for the presence of total antibodies against HAV. The study included 1,499 individuals. The prevalence of anti-HAV was 74.6% (95% CI 72.3-76.8). Univariate analysis showed associations with age (chi-square for linear trend = 496.003, p < 0.001), presence of outside toilet (p < 0.001), history of hepatitis (p < 0.001) and family history of hepatitis (p = 0.05). After adjusting for age, HAV infection also showed an association with the number of people in the family (p = 0.03). The overall prevalence rates were high, but not more than 60% of the children under the age of ten years had already been infected. Very high prevalence was detected only within older cohorts, thus paradoxically defining this as a region with intermediate endemicity, even under the conditions of poverty encountered.

Hepatitis A virus; Epidemiology; Prevalence; Amazon region; Brazil

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