Genetic diversity of the IC/3D7 allelic family of the merozoite surface protein 2 (MSP2) of Plasmodium falciparum and multiplicity of infection in four health facilities in the Mbouda Health District, Cameroon

The genetic variability of Plasmodium falciparum serves as an important marker of the parasite's ability to adapt and develop resistance to antimalarial treatments. This study sought to evaluate the diversity of the P. falciparum merozoite surface protein 2 (msp2) gene among patients receiving care in four health centers in the Mbouda Health District, Cameroon. Blood samples were obtained from 481 individuals who came for diagnostic testing with symptoms suggestive of malaria. Rapid diagnostic tests and thick blood smears were performed to confirm P. falciparum infection and determine parasite density, respectively. Positive samples were spotted onto Whatman filter paper for molecular testing. DNA was extracted using the Chelex-100 technique, and msp2 fragments were amplified via nested PCR. Amplicons were separated on 1.3% agarose gels and visualized under UV light. Phylogenetic analysis was performed in R, and statistical analyses were conducted using SPSS version 23. Out of the 481 samples analyzed, 137 (28.48%) tested positive for P. falciparum, with a mean parasite density of 2196.77 ± 1344.36 parasites/µL. Female participants showed a weakly significant association with malaria infection, while children aged 0-5 years, despite having an odds ratio above 1, did not show a statistically significant association. The msp2 gene was successfully amplified in 64% of positive samples, revealing 15 distinct alleles. The overall genetic diversity was 14.15%, with a mean multiplicity of infection (MOI) of 1.20. The proportions of mono-, double-, and triple-genotype infections were 81.68%, 18.18%, and 1.33%, respectively. Phylogenetic analysis identified 13 distinct clades, indicating genetic relatedness among circulating P. falciparum strains. A considerable level of genetic diversity and multiple infections was detected among P. falciparum isolates in the Mbouda Health District, suggesting high transmission intensity. Further studies incorporating additional molecular markers such as msp1 and GLURP are recommended to provide a more comprehensive picture of P. falciparum genetic variation in the region.