Genetic polymorphism of Merozoite Surface Protein-2 (MSP-2) in Plasmodium falciparum isolates from Pawe District, North West Ethiopia.

BACKGROUND: In malaria endemic regions, Plasmodium falciparum infection is characterized by extensive genetic diversity. Describing this diversity provides important information about the local malaria situation. This study was conducted to evaluate the extent of genetic diversity of P. falciparum in Pawe district, North West Ethiopia, using the highly polymorphic merozoite surface protein 2 gene.

METHODS: Atotal of 92 isolates from patients with uncomplicated P. falciparum attending Pawe Health Centre were collected from September to December 2013. Genomic DNA was extracted using the Chelex method and analyzed by length polymorphism following gel electrophoresis of DNA products from nested PCR of msp2 (block 3), targeting allelic families of FC27 and 3D7/IC.

RESULTS: There were twenty-two different msp2 alleles, 11 corresponding to the 3D7/ IC and 11 to the FC27 allelic family. The frequency of isolates of the msp2 3D7/IC allelic familywas higher (51%) compared to FC27 (49%). The majority of the isolates (76%) contained multiple infections andthe overall mean multiplicity of infection was 2.8 (CI 95% 2.55-3.03). The heterozygosity index was 0.66 for msp2. There was no statically significant difference in the multiplicity of infection by age or parasite density.

CONCLUSIONS: The results of this study show that P.falciparum polymorphismsare extensive in Northwest Ethiopia and most of the infections are composed of multiple clones.