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.