Detection of high frequency of MAD20 allelic variants of Plasmodium falciparum merozoite surface protein 1 gene from Adama and its surroundings, Oromia, Ethiopia

Abstract

Background One of the major challenges in developing an effective vaccine against asexual stages of Plasmodium falciparum is genetic polymorphism within parasite population. Understanding the genetic polymorphism like block 2 region of merozoite surface protein-1 (msp-1) gene of P. falciparum enlighten mechanisms underlining disease pathology, identification of the parasite clone profile from the isolates, transmission intensity and potential deficiencies of the ongoing malaria control and elimination efforts in the locality. Detailed understanding of local genetic polymorphism is an input to pave the way for better management, control and elimination of malaria. The aim of this study was to detect the most frequent allelic variant of the msp-1 gene of P. falciparum clinical isolates from selected health facilities in Adama town and its surroundings, Oromia, Ethiopia. Methods One hundred thirty-nine clinical isolates were successfully amplified for msp-1 gene using specific primers. Nested PCR amplification was conducted targeting K1, MAD20, and R033 alleles followed by gel electrophoresis for fragment analysis. Based on the detection of a PCR fragment, infections were classified as monoclonal or multiple infections. Results 19 different size polymorphism of msp-1 gene were identified in the study, with 67(48%) MAD20, 18 (13%) K-1 and 18 (13%) RO33 allelic family. Whereas, the multiple infections were 21(15%), 8 (5.8%), 4(2.9%), 3(2.2%) for MAD20 + K-1, MAD20 + RO33, K-1 + RO33, and MAD20 + K-1, RO33, respectively. The overall Multiplicity of infection (MOI) was 1.3 and the expected heterozygosity (He) was 0.39 indicating slightly low falciparum malaria transmission. Conclusion The status of msp-1 allele size polymorphism, MOI and He observed in the study revealed the presence of slightly low genetic diversity of P. falciparum clinical isolates. However, highly frequent MAD20 allelic variant was detected from clinical isolates in the study area. Moreover, the driving force that led to high predominance of MAD20 allelic variant revealed in such malaria declining region demands further research.

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

“…The predominance of the MAD 20 for msp1 and the FC27 allelic family for msp2 among P. falciparum isolates was consistent with previous studies done in countries; Myanmar [ 34 ], Vietnam [ 35 ], Indonesia [ 36 ], that showed MAD 20 predominance and Pakistan [ 37 , 38 ], and Malaysia [ 39 ] that reported FC27 of msp2 dominance; The predominance of the MAD 20 for msp1 and the FC27 allelic family for msp2 were reported in other parts of Africa; North Central Nigeria [ 40 ], Equatorial Guinea [ 41 ], and Northwest Ethiopia [ 42 ]. Although this corroborates previous studies from Ethiopia finding similar patterns with the predominance of MAD 20 [ 43 ] and FC27 [ 44 , 45 ]. Predominance of MAD 20 of msp1 and 3D7/IC1 of msp2 in other reports had shown the predominance of K1 of msp1 and 3D7/IC1 of msp2 in southwestern Ethiopia [ 46 ].…”

P. falciparum msp1 and msp2 genetic diversity in P. falciparum single and mixed infection with P. malariae among the asymptomatic population in Southern Benin

“…It also revealed that the RO33 allelic family of msp1 was the most prevalent while a similar frequency was observed for both msp2 allelic families (3D7 and FC27). Studies carried out to assess the association between the distribution of msp1 allelic families and malaria status (asymptomatic and symptomatic) revealed different observations [44][45][46]. However, the RO33 allelic family was frequently reported in asymptomatic malaria cases [47].…”

High prevalence of Pfcrt 76T and Pfmdr1 N86 genotypes in malaria infected patients attending health facilities in East Shewa zone, Oromia Regional State, Ethiopia

“…The areas are characterized by low altitude (< 2000 m above sea level), heavy rainfall pattern from June to August followed by major transmission of malaria from September to December and short rains of February and March contributing for minor malaria transmission from April to May [ 18 ]. Geographical location of the study areas in Great Rift Valley, at low altitude, with rainfall pattern and average annual temperature of 16–32 °C make the areas favorable environments for breeding of Anopheles mosquitoes, of which Anopheles arabiensis is the major malaria vector [ 19 ]. Both P. falciparum and P. vivax co-exist in the area as it is common in different parts of the country.…”

“…Plasmodium falciparum genomic DNA was extracted from dried blood spot (DBS) by Chelex extraction method as described elsewhere [ 19 ]. Extracted DNA was transferred into 0.5 ml tubes and stored at − 20 °C until further use.…”

“…Thirty-eight samples which were microscopically detected as P. falciparum were not amplified particularly for Pfcrt K76T codon. In order to verify the presence of intact genes and quality of DNA for those samples, nested PCR targeting msp-1 of polymorphic region (block-2) was performed as described elsewhere [ 19 ].…”