Genetic analysis of the merozoite surface protein-1 block 2 allelic types in Plasmodium falciparum clinical isolates from Lao PDR

Abstract

BackgroundMSP-1 is one of the potential malarial vaccine candidate antigens. However, extensive genetic polymorphism of this antigen in the field isolates of Plasmodium falciparum represents a major hindrance for the development of an effective vaccine. Therefore, this study aimed to establish the prevalence and genetic polymorphisms of K1, MAD20 and RO33 allelic types of msp-1 block 2 among P. falciparum clinical isolates from Lao PDR.MethodsPlasmodium falciparum isolates were collected from 230 P. falciparum-infected blood samples from three regions of Lao PDR. K1, MAD20 and RO33 were detected by nested PCR; SSCP was used for polymorphism screening. The nested PCR products of each K1, MAD20 and RO33 allelic types that had different banding patterns by SSCP, were sequenced.ResultsThe overall prevalence of K1, MAD20 and RO33 allelic types in P. falciparum isolates from Lao PDR were 66.95%, 46.52% and 31.30%, respectively, of samples under study. Single infections with K1, MAD20 and RO33 allelic types were 27.83%, 11.74% and 5.22%, respectively; the remainders were multiple clonal infections. Neither parasite density nor age was related to MOI. Sequence analysis revealed that there were 11 different types of K1, eight different types of MAD20, and 7 different types of RO33. Most of them were regional specific, except type 1 of each allelic type was common found in 3 regions under study.ConclusionsGenetic polymorphism with diverse allele types was identified in msp-1 block 2 among P. falciparum clinical isolates in Lao PDR. A rather high level of multiple clonal infections was also observed but the multiplicity of infection was rather low as not exceed 2.0. This basic data are useful for treatment and malaria control program in Lao PDR.

Genetic polymorphism of merozoite surface protein-1 and merozoite surface protein-2 inPlasmodium falciparumisolates from children in South of Benin

“…For these authors, the multiplicity of infection with P. falciparum could be a potentially useful parameter in the evaluation of interventions against malaria. Several studies have shown a correlation between the MOI and parasite density, but in our study, the MOI did not increase with higher densities similar to results of other studies conducted elsewhere [10, 18]. …”

Genetic diversity of Plasmodium falciparum populations in southeast and western Myanmar

“…It was noteworthy that the frequency of the RO33 allele in the present study ranged from 15.28 to 32.76%, which is distinct from the rare presence of this type in parasites from the central Myanmar [18]. For Msp2 , the 3D7 type was more abundant than the FC27 type, which was similar to what has been reported from the Thai-Myanmar border [17], but different from results in the northeastern Myanmar [5] and Laos [19]. Interestingly, all three sites shared the same most prevalent Msp2 allele (3D7 type, allele size 450–550 bp).…”

Genetic Diversity of Variable Region Block 2 in the Merozoite Surface Protein-1 (MSP1) in Plasmodium falciparum Field Isolates from South-East of Iran

“…These findings are similar to previous studies in Iran, Pakistan, Myanmar, Bangladesh and Colombia which demonstrated the predominance of the MAD20 [7,16,17,19,20]. By contrast, previous studies in Lao PDR, Zambia, Gabon, Congo and other African countries showed that K1 was the predominant allelic family [21][22][23][24]. Monomorphic band of RO33 allelic types in Iran were observed on agarose gel electrophoresis.…”