Genetic Diversity and Allelic Distribution of Plasmodium falciparum msp1 and msp2 Genes in a High-Transmission Setting: Southern Ethiopia.

Abstract

Background: Although both preventable and treatable, malaria remains a significant burden on health and economic stability, particularly in regions of high transmission such as Africa and parts of Asia. The parasite's genetic diversity enhances its ability to evade the host immune system and adapt, posing challenges to effective treatment strategies.

Objective: The primary objective of this study was to assess the genetic diversity of Plasmodium falciparum by analyzing polymorphisms in the merozoite surface protein genes among clinical isolates collected from public health facilities in Arba Minch town and Mirab Abaya, Southern Ethiopia.

Methods: A facility-based cross-sectional study was conducted to investigate the genetic diversity of P. falciparum. Capillary blood samples were collected from 200 participants using both microscope slides (for phenotypic analysis) and Whatman 903 filter paper (for molecular investigation using polymerase chain reaction). Parasite genomic DNA was extracted using the G-spin Total DNA Extraction Mini Kit. Nested PCR was performed to confirm the presence of P. falciparum by targeting 18S rRNA and to genotype the msp1 and msp2 gene allelic families.

Results: Of the 200 samples initially confirmed for P. falciparum infection, 138 (69%) were mono-infections. Males accounted for 55.1% of the confirmed cases, whereas 44.9% were females. More than half of the participants (58%) had parasite density of ≥ 10,000 parasites/μL. The mean hemoglobin level recorded was 13.4 g/dL (95% CI, 13.06-13.7). Genotyping revealed 131 msp1 and 164 for msp2 alleles, with MAD20 (58.8%) and FC27 (52.4%) frequently detected allelic types, respectively. msp2 infections were nearly evenly split between monoclonal (53.2%) and polyclonal. A significantly higher multiplicity of infection (MOI) was observed in Arba Minch town for msp2 (MOI = 2.19) p < 0.001.

Conclusion and recommendation: This study revealed substantial genetic diversity in P. falciparum alleles, with variations linked to geographic location, age group, and residential setting. These findings underscore the complex epidemiology of malaria in Arba Minch and the surrounding areas, emphasizing the need for geographically and demographically targeted control strategies based on local transmission patterns to guide elimination efforts. Enhancing community awareness about risk factors and vulnerable populations is critical for the success of malaria prevention programs.