Low genetic diversity and complexity of submicroscopic Plasmodium falciparum infections among febrile patients in low transmission areas in Senegal

Abstract

Introduction Submicroscopic Plasmodium infections are common in malaria endemic countries, but very little studies have been done in Senegal. This study investigates the genetic diversity and complexity of submicroscopic P . falciparum infections among febrile patients in low transmission areas in Senegal. Materials and methods Hundred and fifty blood samples were collected from febrile individuals living in Dielmo and Ndiop (Senegal) between August 2014 and January 2015, tested for microscopic and sub-microscopic P . falciparum infections and characterized for their genetic diversity and complexity of infections using msp-1 and msp-2 genotyping. Results Submicroscopic P . falciparum infections were 19.6% and 25% in Dielmo and Ndiop, respectively. K1 and 3D7 were the predominant msp-1 and msp-2 allelic types with respective frequencies of 67.36% and 67.10% in microscopic isolates and 58.24% and 78% in submicroscopic ones. Frequencies of msp-1 allelic types were statistically comparable between the studied groups (p>0.05), and were respectively 93.54% vs 87.5% for K1, 60% vs 54.83% for MAD20 and 41.93% vs 22.5% for RO33 while frequencies of msp-2 allelic types were significantly highest in the microscopy group for FC27 (41.93% vs 10%, Fisher’s Exact Test, p = 0.001) and 3D7 (61.29% vs 32.5%, Fisher’s Exact Test, p = 0.02). Multiplicities of infection were lowest in submicroscopic P . falciparum isolates. Conclusions The study revealed a high submicroscopic P . falciparum carriage among patients in the study areas, and that submicroscopic P . falciparum isolates had a lower genetic diversity and complexity of malaria infections.

Temporal Changes in Genetic Diversity of Plasmodium Falciparum Populations in Isolates from Asymptomatic Children in Brazzaville after the Introduction of ACT

“…The Republic of Congo is considered a highly endemic country for malaria with a high level of malaria transmission. Studies conducted in low transmission areas show that the genetic diversity of Pfmsp1 and Pfmsp2 is low contrary to what used to be observed in high transmission areas, where genetic diversity is also high [20,21,23,24].…”

Plasmodium falciparum genetic diversity and multiplicity of infection based on msp-1, msp-2, glurp and microsatellite genetic markers in sub-Saharan Africa: a systematic review and meta-analysis

“…The mean values of parasite genetic diversity and MOI are higher in areas with high malaria transmission intensity [ 16 , 17 ] and lower in those with low transmission intensity [ 18 ]. Additionally, mean Plasmodium falciparum genetic diversity and MOI apparently decreased following the suppression of Plasmodium falciparum transmission intensity in areas of Ethiopia [ 19 ] and Senegal [ 20 ]. In other studies, mean values of Plasmodium falciparum genetic diversity were higher among individuals with symptomatic infections [ 21 , 22 ] and lower in those with asymptomatic infections [ 23 ], and were inversely correlated with parasite density and patient age [ 24 ].…”

Strong isolation by distance and evidence of population microstructure reflect ongoing Plasmodium falciparum transmission in Zanzibar

“…Parasite genomics has the potential to help us better understand malaria epidemiology by uncovering population structure and gene flow, providing insight into the changes in the parasite population including how parasites move between regions ( Neafsey et al, 2021 ). Genomics has previously been used to study importation and transmission chains in other low-transmission settings in Africa and elsewhere ( Chang et al, 2019 ; Fola et al, 2023 ; Morgan et al, 2020 ; Patel et al, 2014 ; Roh et al, 2019 ; Sane et al, 2019 ). Previously, we had investigated the importation of malaria into Zanzibar from the mainland using whole-genome sequencing, showing highly similar populations within the mainland and within the archipelago, but also identifying highly related parasite pairs between locations, suggesting a role for importation ( Morgan et al, 2020 ).…”