RESUMO
The authors describe the baseline malaria prevalence and arbovirus seroprevalence among 467 subjects in an ongoing cohort study in rural Amazonia. Most subjects (72.2%) reported one or more previous episodes of malaria, and 15.6% had been hospitalized for malaria, but only 3.6% of individuals five years or older had malaria parasites detected by microscopy (10 with Plasmodium vivax and 4 with P. falciparum). Antibodies to Alphavirus, Orthobunyavirus, and/or Flavivirus were detected by hemagglutination inhibition (HI) in 42.6% of subjects aged five years or older, with a higher seropositivity rate among males (49.2%) than females (36.2%). Since 98.9% of subjects had been immunized for yellow fever, the presence of cross-reactive antibodies to dengue and other Flaviviruses cannot be ruled out, but at least 12 subjects (3.3%) with IgM antibodies to dengue virus detected by ELISA had a putative recent exposure to this virus.
Assuntos
Infecções por Arbovirus/epidemiologia , Doenças Endêmicas , Malária/epidemiologia , Adolescente , Adulto , Anticorpos Antivirais/sangue , Infecções por Arbovirus/imunologia , Arbovírus/imunologia , Brasil/epidemiologia , Criança , Pré-Escolar , Reações Cruzadas , Vírus da Dengue/imunologia , Ecossistema , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunoglobulina G/sangue , Lactente , Malária/imunologia , Masculino , Pessoa de Meia-Idade , Prevalência , População Rural , Estudos Soroepidemiológicos , Fatores SexuaisRESUMO
The authors describe the baseline malaria prevalence and arbovirus seroprevalence among 467 subjects in an ongoing cohort study in rural Amazonia. Most subjects (72.2 percent) reported one or more previous episodes of malaria, and 15.6 percent had been hospitalized for malaria, but only 3.6 percent of individuals five years or older had malaria parasites detected by microscopy (10 with Plasmodium vivax and 4 with P. falciparum). Antibodies to Alphavirus, Orthobunyavirus, and/or Flavivirus were detected by hemagglutination inhibition (HI) in 42.6 percent of subjects aged five years or older, with a higher seropositivity rate among males (49.2 percent) than females (36.2 percent). Since 98.9 percent of subjects had been immunized for yellow fever, the presence of cross-reactive antibodies to dengue and other Flaviviruses cannot be ruled out, but at least 12 subjects (3.3 percent) with IgM antibodies to dengue virus detected by ELISA had a putative recent exposure to this virus.