Genetic Diversity and Phylogenetic Relatedness of Cameroonian Plasmodium falciparum Isolates and Comparative Analysis with Global Populations.

PURPOSE

Plasmodium falciparum (Pf) is the deadliest malaria parasite species, and its genetic diversity is a significant obstacle to its effective control. Here, we analyzed the genetic diversity and phylogeny of Pf isolates collected in Cameroon using merozoite surface proteins 1 and 2 (msp1/2) markers.

METHODS

Samples were collected in three malaria epidemiological facets of three regions of Cameroon (Littoral, North, Far North). The msp1 block 2 and msp2 block 3 were genotyped using polymerase chain reaction and Sanger sequencing. The structural organization the msp1/2 allelic families (K1, MAD20, and RO33 for msp1, IC/3D7, and FC27 for msp2) was analyzed, while their phylogenetic relatedness was assessed in comparison with ~ 2500 good quality sequences from various geographical areas.

RESULTS

The K1 and MAD20 families had high structural diversity due to the repetition of 3-amino acid repeats (SGT, SGP, and SAQ for K1, SGG, and SVA for MAD20). RO33 sequences presented several mutation points. Tetramer to decamer repetitive amino acids were identified in IC/3D7 sequences mainly GSGA (31.3%) and GASGSA (25%). The 32-aa sequence of the FC27 family showed non-synonymous substitution, insertion, and deletions. The K1 and RO33 sequences were phylogenetically closer to those from China/Myanmar, while MAD20, IC/3D7, and FC27 sequences were closer to those from India, Panama, and Papua New Guinea. The Cameroonian Pfmsp1/2 sequences showed a high genetic structure with phylogenetic patterns outlining a complex Pf population structure.