Low genetic diversity of Plasmodium falciparum merozoite surface protein 1 and 2 and multiplicity of infections in western Ethiopia following effective malaria interventions

• Published in: Malaria journal 2022-12, Vol.21 (1), p.383-383, Article 383
• Main Authors: Tadele, Geletta, Jaiteh, Fatou K, Oboh, Mary, Oriero, Eniyou, Dugassa, Sisay, Amambua-Ngwa, Alfred, Golassa, Lemu
• Format: Article
• Language: English
• Subjects: Adolescent; Alleles; Antigens, Protozoan - genetics; Child; Cloning; Deoxyribonucleic acid; DNA; Ethiopia - epidemiology; Gene polymorphism; Genetic diversity; Genetic Variation; Genotype; Genotyping; Health facilities; Heterozygosity; Human diseases; Humans; Infections; Insecticides; Malaria; Malaria transmission; Malaria, Falciparum - epidemiology; Malaria, Falciparum - parasitology; Male; Membrane Proteins - genetics; Merozoite surface protein 1; Merozoite Surface Protein 1 - genetics; Merozoite surface protein 2; MOI; Multiplicity of infection; Nucleotide sequence; P. falciparum; Parasites; PCR; Plasmodium falciparum; Plasmodium falciparum - genetics; Polymerase chain reaction; Proteins; Protozoan Proteins - genetics; Public health; Regions; Sample size; Software; Vector-borne diseases; Western Ethiopia
• ISSN: 1475-2875; 1475-2875
• DOI: 10.1186/s12936-022-04394-1

Genetic diversity of malaria parasites can inform the intensity of transmission and poses a major threat to malaria control and elimination interventions. Characterization of the genetic diversity would provide essential information about the ongoing control efforts. This study aimed to explore allelic polymorphism of merozoite surface protein 1 (msp1) and merozoite surface protein 2 (msp2) to determine the genetic diversity and multiplicity of Plasmodium falciparum infections circulating in high and low transmission sites in western Ethiopia. Parasite genomic DNA was extracted from a total of 225 dried blood spots collected from confirmed uncomplicated P. falciparum malaria-infected patients in western Ethiopia. Of these, 72.4% (163/225) and 27.6% (62/225) of the samples were collected in high and low transmission areas, respectively. Polymorphic msp1 and msp2 genes were used to explore the genetic diversity and multiplicity of falciparum malaria infections. Genotyping of msp1 was successful in 86.5% (141/163) and 88.7% (55/62) samples collected from high and low transmission areas, respectively. Genotyping of msp2 was carried out among 85.3% (139/163) and 96.8% (60/62) of the samples collected in high and low transmission sites, respectively. Plasmodium falciparum msp1 and msp2 genes were amplified by nested PCR and the PCR products were analysed by QIAxcel ScreenGel Software. A P-value of less or equal to 0.05 was considered significant. High prevalence of falciparum malaria was identified in children less than 15 years as compared with those  ≥ 15 years old (AOR = 2.438, P = 0.005). The three allelic families of msp1 (K1, MAD20, and RO33) and the two allelic families of msp2 (FC27 and 3D7), were observed in samples collected in high and low transmission areas. However, MAD 20 and FC 27 alleles were the predominant allelic families in both settings. Plasmodium falciparum isolates circulating in western Ethiopia had low genetic diversity and mean MOI. No difference in mean MOI between high transmission sites (mean MOI 1.104) compared with low transmission area (mean MOI 1.08) (p > 0.05). The expected heterozygosity of msp1 was slightly higher in isolates collected from high transmission sites (He = 0.17) than in those isolates from low transmission (He = 0.12). However, the heterozygosity of msp2 was not different in both settings (Pfmsp2: 0.04 in high transmission; pfmsp2: 0.03 in low transmission). Plasmodium falciparum from clinical malaria cases in w