Análise do perfil genético de marcadores de resistência a antimaláricos em isolados de campo de p. falciparum e p. vivax de 12 localidades malarígenas do estado do Amazonas.

Abstract

In the legal Amazon, the Amazon state registered 180.290 malaria cases in 2006, that fact carries in huge economic and social impact for the region. The diagnosis is traditionally performed by the method of the giemsa stained thick blood smear, however low-level parasitemias and mixed infections are frequently not detected. These disadvantages justify the use of more sensitive and specific methodologies as the Polimerase Chain Reaction (PCR). The elevated cost of this method is one of the factors that prevent your utilization as routine in the different endemic regions. The PCR method is a technic that has been already implemented alternatively for drug monitoring, detections of mixed infections and genotyping studies. The present work had for goal the molecular characterization of Plasmodium falciparum and P. vivax field isolates of 12 endemic areas in Amazon state: Manaus, Careiro, Borba, Autazes, Itacoatira, Presidente Figueiredo, Barcelos, São da Cachoeira, Coari, Tefé, Guajará and Humaitá. The samples were obtained by microscopy diagnosis and the study of mixed infections was done through nested-PCR. Additionally was standardized methodology in real time to hasten and to give more reliability to the samples diagnosis used in studies developed by the malaria management of the Fundação de Medicina Tropical do Amazonas (FMTAM). The genes used to P. falciparum´s characterization were pfcrt and pfatp6, and for P. vivax was used the gene pvmdr, using the automatic sequencing and for genotiping assays using Real Time probes detection. All P. falciparum samples analyzed for the gene pfcrt demonstrated similar genetic profile to 7G8 strain control, which has the mutation K76T, proving the resistant phenotype observed in previous studies. For the gene pfatp6 were described 3 distinct haplotypes, with mutations identified in the positions 1204, 1888 and 2694. The analysis of the gene pvmdr in P. vivax identified mutations in codons 976 and 1076 in 11 samples of 100 total analyzed, distributed among four areas, Autazes, Coari, Manaus and Tefé. The identification of Plasmodium population´s genetic profile circulating in Amazon region is an important tool to understand the transmission dynamics of malaria and essential for constant monitoring the disease control actions