Genetic Polymorphism ofmsp1 andmsp2 inPlasmodium falciparumIsolates from Côte d’Ivoire versus Gabon

Abstract

Introduction. The characterization of genetic profile of Plasmodium isolates from different areas could help in better strategies for malaria elimination. This study aimed to compare P. falciparum diversity in two African countries. Methods. Isolates collected from 100 and 73 falciparum malaria infections in sites of Côte d'Ivoire (West Africa) and Gabon (Central Africa), respectively, were analyzed by a nested PCR amplification of msp1 and msp2 genes. Results. The K1 allelic family was widespread in Côte d'Ivoire (64.6%) and in Gabon (56.6%). For msp2, the 3D7 alleles were more prevalent (>70% in both countries) compared to FC27 alleles. In Côte d'Ivoire, the frequencies of multiple infections with msp1 (45.1%) and msp2 (40.3%) were higher than those found for isolates from Gabon, that is, 30.2% with msp1 and 31.4% with msp2. The overall complexity of infection was 1.66 (SD = 0.79) in Côte d'Ivoire and 1.58 (SD = 0.83) in Gabon. It decreased with age in Côte d'Ivoire in contrast to Gabon. Conclusion. Differences observed in some allelic families and in complexity profile may suggest an impact of epidemiological facies as well as immunological response on genetic variability of P. falciparum.

Genetic diversity and genotype multiplicity of Plasmodium falciparum infection in patients with uncomplicated malaria in Chewaka district, Ethiopia

“…This was higher compared to those reported from a moderate transmission settings in Kolla-Shele, Southwest Ethiopia [46], but consistent with findings from Northwest Ethiopia [50]. Despite the lack of entomological data such as entomological inoculation rate (EIR) from Chewaka district, the number of clones coinfecting a single host can be used as an indicator of the level of malaria transmission or the level of host acquired immunity [54,59,60]. Besides, transmission intensity can also be affected by other factors such as vector biting behavior and endemicity [54].…”

“…Furthermore, genetic diversity values were higher based on heterozygosity index for msp-2 (He=0.85), than for msp-1 (He=0.43), suggesting a large genotype diversity within the msp-2 locus, which was higher than previously reported in Ethiopia [46]. In contrast, declining rates of diversity of alleles (heterozygosity) in P.falciparum area associated with decreasing transmission rates [54,60].…”

“…However, studies in Northern Ethiopia [50] and Malaysia [53] reported Mad20 allele was predominant. Variations in the prevalence of block 2 alleles between different studies likely reflects the differences in geographic locations and local transmission intensity [54,55]. The RO33 family was poorly polymorphic with only one allele (160bp).…”

“…Despite the lack of entomological data such as entomological inoculation rate (EIR) from Chewaka district, the number of clones coinfecting a single host can be used as an indicator of the level of malaria transmission or the level of host acquired immunity [54,59,60]. Besides, transmission intensity can also be affected by other factors such as vector biting behavior and endemicity [54]. Inferring high transmission intensity from the presence of multi-clonal infections alone has additional limitations including estimates of MOI varying by genotyping method, potential impact from sampling frequency and a non-linear relationship between MOI and transmission intensity [54].…”

“…Besides, transmission intensity can also be affected by other factors such as vector biting behavior and endemicity [54]. Inferring high transmission intensity from the presence of multi-clonal infections alone has additional limitations including estimates of MOI varying by genotyping method, potential impact from sampling frequency and a non-linear relationship between MOI and transmission intensity [54]. Despite these limitations, infection with multiple clones observed in this study, combined with evidence of high genetic diversity would be consistent with high transmission intensity in the study area.…”