Plasmodium falciparum: genetic polymorphism of the merozoite surface antigen 2 gene of strains from India

Bhattacharya, Pramatha R.

doi:10.1016/s0035-9203(98)90758-1

Cited by 5 publications

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References 9 publications

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“…Bhattacharya and others have shown only point mutations in MSA-2 gene among Indian laboratory and field isolates. 9,10 In contrast, we show in this report larger deletions/additions (detected by agarose gel electrophoresis) not only for the MSA-2 gene but also for MSA-1 and CSP genes among field isolates from hyperendemic and non-hyperendemic regions of India. The present study also shows an increase in the number of variants and mixed alleles with malaria hyperendemicity.…”

contrasting

confidence: 85%

“…9,10 This discrepancy could be due to differences in either the sample sizes or the study areas. However, we observed this size variation even in our smallest sample size of 11 from Jabalpur.…”

Section: Discussionmentioning

confidence: 99%

“…This sample size is similar to that of previous studies combined. 9,10 Therefore, this discrepancy in the observations could be due to differences in sample size and site of collection.…”

Section: Discussionmentioning

confidence: 99%

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Genetic polymorphism of falciparum malaria vaccine candidate antigen genes among field isolates in India.

Ranjit

Sharma²

1999

The American Journal of Tropical Medicine and Hygiene

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Abstract. The present study was designed to investigate the genetic diversity of Plasmodium falciparum among field isolates from India. A total of 71 clinical isolates were analyzed by the polymerase chain reaction (PCR) for the amplification of repeat regions of malaria vaccine candidate antigen genes, i.e., merozoite surface antigen-1 (MSA-1), MSA-2, and circumsporozoite protein (CSP). All three genes showed variation; MSA-2 has the maximum number of 10 variant forms while MSA-1 and CSP had 8 and 6 variants, respectively. Some variant forms were more common than others among the clinical isolates. There were mixed alleles for each gene in several (27 of (Orissa) not only showed the maximum number of variant forms of each gene but also the maximum number of cases with mixed alleles compared with the non-hyperendemic regions (Madhya Pradesh and Rajasthan). The presence of such large numbers of P. falciparum strains in India should be taken into account in future malaria vaccine programs.Malaria currently remains uncontrolled despite immense efforts being made to contain the disease. The unavailability of a suitable malaria vaccine and emergence of drug-resistant parasites are further complicating the situation in tropical areas. Of the four species of human malaria parasites, Plasmodium falciparum is most lethal and causes epidemics in tropical countries. 1,2 Although several vaccine candidate antigens of P. falciparum have been identified and characterized, the availability of a universal malaria vaccine is still a remote possibility. One reason is the antigenic variation of different geographic isolates of the parasite. The most common and widely characterized vaccine candidate antigens are circumsporozoite protein (CSP) and merozoite surface antigens-1 and -2 (MSA-1 and MSA-1). Allelic forms of these antigen genes have been reported in the literature among several laboratory and wild type field isolates from different parts of the world. 3-8 However, there is limited information on the polymorphic nature of these genes among field isolates from India. Bhattacharya and others have shown only point mutations in MSA-2 gene among Indian laboratory and field isolates. 9,10 In contrast, we show in this report larger deletions/additions (detected by agarose gel electrophoresis) not only for the MSA-2 gene but also for MSA-1 and CSP genes among field isolates from hyperendemic and non-hyperendemic regions of India. The present study also shows an increase in the number of variants and mixed alleles with malaria hyperendemicity. MATERIALS AND METHODSPatients and blood collection. Patients with fever attended malaria clinics at primary health centers (PHCs) or district hospitals. Fingerprick blood was examined for the presence of malarial parasites by light microscopy after Giemsa staining. Approximately 20 l of fingerprick blood was collected from those patients who were confirmed to be positive for the presence of P. falciparum parasites. These patients were informed in the local language about the nature of the expe...

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confidence: 85%

Section: Discussionmentioning

confidence: 99%

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Genetic polymorphism of falciparum malaria vaccine candidate antigen genes among field isolates in India.

Ranjit

Sharma²

1999

The American Journal of Tropical Medicine and Hygiene

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“…Protocols are comparably simple without requiring expensive equipment. In many populations, high diversity of size-polymorphic antigens has been observed in both P. falciparum [ 33 , 34 , 38 , 43 , 46 – 53 ] and P. vivax [ 54 – 63 ]. Antigens are likely under immune selection, which will affect the distribution of alleles in the population.…”

Section: Size-polymorphic Antigens and Microsatellitesmentioning

confidence: 99%

Molecular approaches to determine the multiplicity of Plasmodium infections

Zhong

Koepfli

Cui

et al. 2018

Malar J

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Multiplicity of infection (MOI), also termed complexity of infection (COI), is defined as the number of genetically distinct parasite strains co-infecting a single host, which is an important indicator of malaria epidemiology. PCR-based genotyping often underestimates MOI. Next generation sequencing technologies provide much more accurate and genome-wide characterization of polyclonal infections. However, complete haplotype characterization of multiclonal infections remains a challenge due to PCR artifacts and sequencing errors, and requires efficient computational tools. In this review, the advantages and limitations of current molecular approaches to determine multiplicity of malaria parasite infection are discussed.

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“…are reported from different regions of the globe [1-13]. However, limited reports are available on the genetic diversity existing among P. falciparum population of India [14-19]. This paper reports polymorphism observed in merozoite surface protein genes ( msp-1 and msp-2 ) among field isolates of P. falciparum collected from north-eastern and eastern regions of India.…”

Section: Introductionmentioning

confidence: 99%

Genetic structure of Plasmodium falciparum field isolates in eastern and north-eastern India

Joshi

Valecha

Verma

et al. 2007

Malar J

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Background: Molecular techniques have facilitated the studies on genetic diversity of Plasmodium species particularly from field isolates collected directly from patients. The msp-1 and msp-2 are highly polymorphic markers and the large allelic polymorphism has been reported in the block 2 of the msp-1 gene and the central repetitive domain (block3) of the msp-2 gene. Families differing in nucleotide sequences and in number of repetitive sequences (length variation) were used for genotyping purposes. As limited reports are available on the genetic diversity existing among Plasmodium falciparum population of India, this report evaluates the extent of genetic diversity in the field isolates of P. falciparum in eastern and north-eastern regions of India. Methods: A study was designed to assess the diversity of msp-1 and msp-2 among the field isolates from India using allele specific nested PCR assays and sequence analysis. Field isolates were collected from five sites distributed in three states namely, Assam, West Bengal and Orissa. Results: P. falciparum isolates of the study sites are highly diverse in respect of length as well as sequence motifs with prevalence of all the reported allelic families of msp-1 and msp-2. Prevalence of identical allelic composition as well as high level of sequence identity of alleles suggest a considerable amount of gene flow between the P. falciparum populations of different states. A comparatively higher proportion of multiclonal isolates as well as multiplicity of infection (MOI) was observed among isolates of highly malarious districts Karbi Anglong (Assam) and Sundergarh (Orissa). In all the five sites, R033 family of msp-1 was observed to be monomorphic with an allele size of 150/160 bp. The observed 80-90% sequence identity of Indian isolates with data of other regions suggests that Indian P. falciparum population is a mixture of different strains.Conclusion: The present study shows that the field isolates of eastern and north-eastern regions of India are highly diverse in respect of msp-1 (block 2) and msp-2 (central repeat region, block 3). As expected Indian isolates present a picture of diversity closer to southeast Asia, Papua New Guinea and Latin American countries, regions with low to meso-endemicity of malaria in comparison to African regions of hyper-to holo-endemicity.

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Plasmodium falciparum: genetic polymorphism of the merozoite surface antigen 2 gene of strains from India

Cited by 5 publications

References 9 publications

Genetic polymorphism of falciparum malaria vaccine candidate antigen genes among field isolates in India.

Genetic polymorphism of falciparum malaria vaccine candidate antigen genes among field isolates in India.

Molecular approaches to determine the multiplicity of Plasmodium infections

Genetic structure of Plasmodium falciparum field isolates in eastern and north-eastern India

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