Genetic Polymorphism of Plasmodium falciparum Merozoite Surface Protein-1 and -2 and Diversity of Drug Resistance Genes in Blood Donors from Bamako, Mali

We examined malaria infection in asymptomatic blood donors from Mali, analyzing allelic diversity of Plasmodium falciparum (Pf) merozoite surface proteins (msp) -1 and -2 as well as the distribution of sulphadoxine-pyrimethamine (SP) resistance genes. A total of 140 genomic DNA samples were screened. Allele-specific nested polymerase chain reaction (PCR) analysis of Pfmsp-1 and Pfmsp-2 was performed, plus fragment analysis of the polymorphic regions to identify allelic diversity of the parasite population. We found parasite positivity due to Pf alone in 20.7% of these donors. Diverse allelic polymorphism of Pfmsp-1 and Pfmsp-2 was identified, with a high rate of multiplicity of infection (1.84 and 1.82 for Pfmsp-1 and Pfmsp-2, respectively). In addition, we found a high degree of SP resistance, with mutations at several dhfr and dhps codons. We conclude that there is an extensive diversity of Pfmsp-1 and Pfmsp-2 allelic types and SP drug resistance in Pf-infected donors from Mali.