Analysis of genetic variability of Plasmodium vivax isolates from different Brazilian Amazon areas using tandem repeats

This work was supported by the Fundação de Amparo à Pesquisa de Minas Gerais (Fapemig), the Conselho Nacional de Pesquisa (CNPq), and PAPES/FIOCRUZ.Fundação Oswaldo Cruz. Centro de Pesquisa Rene Rachou. Laboratoryo of Malaria. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Biologia Geral. Belo Horizonte, MG, Brazil.Faculdade SEAMA. Macapá, AP, Brazil.Universidade Federal do Mato Grosso. Departamento de Clínica Médica. Cuiabá, MT, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Fundação Oswaldo Cruz. Centro de Pesquisa Rene Rachou. Laboratory of Malaria. Belo Horizonte, MG, Brazil.Fundação Oswaldo Cruz. Centro de Pesquisa René Rachou. Laboratory of Malaria. Belo Horizonte, MG, Brazil.Few genetic markers have been described to analyze populations of Plasmodium vivax . The genetic variability of P. vivax has been analyzed mainly among isolates taken from areas ranging from hyper- to holoendemic areas. These studies of genetic variability have neglected many areas with different epidemiologic profiles. The purpose of this study was to analyze the genetic variability of P. vivax isolates from four different Brazilian Amazon areas. We chose to study the five most polymorphic tandem repeats (TRs) identified so far. All TRs studied were polymorphic in at least one studied population, with a modal allele at nearly all loci. Expected heterozygosity ranged from 0.462 to 0.666 and did not correlate with the repeat array length. The genetic distances among the populations varied from 0.027 to 0.241, and did not correlate with their geographic separation. Tandem repeats identified in P. vivax isolates failed to allow geographic clustering

Anti-Plasmodium vivax duffy binding protein antibodies measure exposure to malaria in the Brazilian Amazon

This work was supported by the UNICEF/UNDP/ Word Bank/WHO Special Program for Research and Training in Tropical Diseases (TDR), the Brazilian National Research Council (CNPq), and Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG).Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Malária. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Universidade Federal de Mato Grosso. Hospital Júlio Muller. Cuiabá, MT, Brazil.Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Malária. Belo Horizonte, MG, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Belém, PA, Brasil.Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Malária. Belo Horizonte, MG, Brasil.University of Notre Dame. Department of Biological Sciences. Notre Dame, IN.Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Malária. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Plasmodium vivax Duffy binding protein (DBP) is functionally important in the erythrocyte invasion process and provides a logical target for vaccine-mediated immunity. In the current study, we demonstrated that DBP is naturally immunogenic in different populations of the Brazilian Amazon, and the proportions of DBP IgG positive subjects increased with exposure to malaria, reaching a peak in those subjects with long-term exposure (> 15 years) in the Amazon area. This profile of antibody response was significantly different from the one observed for the P. vivax merozoite surface protein 1 (MSP119), which was relatively uniform in areas with markedly different levels of malaria transmission. In a small sample of adults with symptomless P. vivax infection, we could not detect any significant correlation between antibodies against these P. vivax proteins and asymptomatic infection. Our study provided an additional insight by demonstrating cumulative exposure as a determinant that acts independently of host age in generation of anti-DBP IgG response