Genetic polymorphism of merozoite surface protein-1 (MSP-1) block 2 allelic types in Plasmodium falciparum field isolates from mountain and coastal area in West Sumatera, Indonesia

Background: the field isolates of p. falciparum may display variant forms and different frequencies. this study was designed to know the diversity of allelic type of msp-1 block 2 among p. falciparum isolates collected in a mountain and a coastal area in west sumatera, indonesia, and compare mountain and coastal area. methods: a total of 56 p falciparum infected blood samples, collected from 27 patients attending local health facilities in south solok district in a mountain region and 29 patients attending a local health facilities in south coastal district region, west sumatera, indonesia were used in this study. the regions flanking the highly polymorphic characters, block 2 for msp-1, were genotyped by allele-specific nested-pcr to analyse the population diversity of parasite. sequence analysis of the polymorphic regions of msp-1 was also conducted to identify allelic diversity in the parasite population. results: diverse allelic polymorphism of msp-1 was identified in p. falciparum isolates from a mountain area and a coastal area in west sumatera, indonesia, and most of the infections were determined to be mixed infections. sequence analysis of msp-1 block 2 revelaled that 16 different alleles for msp-1 (3 for k1 type, 2 for mad20 type and 2 for ro33 type) were identified. conclusion: extensive genetic polymorphism with diverse allele type was identified in msp-1 in p. falciparum field isolates from a mountain and a coastal area. a high level of mixed infections was also obcserved, as was a high degree of multiplicity of infection. (med j indones 2011; 20:11-4)