Summary: | <p>Abstract</p> <p>Background</p> <p>Merozoite surface protein-1 (MSP-1) and MSP-2 of <it>Plasmodium falciparum </it>are potential vaccine candidate antigens for malaria vaccine development. However, extensive genetic polymorphism of the antigens in field isolates of <it>P. falciparum </it>represents a major obstacle for the development of an effective vaccine. In this study, genetic polymorphism of MSP-1 and MSP-2 among <it>P. falciparum </it>field isolates from Myanmar was analysed.</p> <p>Methods</p> <p>A total of 63 <it>P. falciparum </it>infected blood samples, which were collected from patients attending a regional hospital in Mandalay Division, Myanmar, were used in this study. The regions flanking the highly polymorphic characters, block 2 for MSP-1 and block 3 for MSP-2, were genotyped by allele-specific nested-PCR to analyse the population diversity of the parasite. Sequence analysis of the polymorphic regions of MSP-1 and MSP-2 was also conducted to identify allelic diversity in the parasite population.</p> <p>Results</p> <p>Diverse allelic polymorphism of MSP-1 and MSP-2 was identified in <it>P. falciparum </it>isolates from Myanmar and most of the infections were determined to be mixed infections. Sequence analysis of MSP-1 block 2 revealed that 14 different alleles for MSP-1 (5 for K1 type and 9 for MAD20 type) were identified. For MSP-2 block 3, a total of 22 alleles (7 for FC27 type and 15 for 3D7 type) were identified.</p> <p>Conclusion</p> <p>Extensive genetic polymorphism with diverse allele types was identified in MSP-1 and MSP-2 in <it>P. falciparum </it>field isolates from Myanmar. A high level of mixed infections was also observed, as was a high degree of multiplicity of infection.</p>
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