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Infection, Genetics and Evolution :... Oct 2018Plasmodium vivax resistance to chloroquine (CQ) was first reported over 60 years ago. Here we analyzed sequence variations in the multidrug resistance 1 gene (Pvmdr1),...
Plasmodium vivax resistance to chloroquine (CQ) was first reported over 60 years ago. Here we analyzed sequence variations in the multidrug resistance 1 gene (Pvmdr1), a putative molecular marker for P. vivax CQ resistance, in field isolates collected from three sites in Thailand during 2013-2016. Several single nucleotide polymorphisms previously implicated in reduced CQ sensitivity were found. These genetic variations encode amino acids in the two nucleotide-binding domains as well as the transmembrane domains of the protein. The high level of genetic diversity of Pvmdr1 provides insights into the evolutionary history of this gene. Specifically, there was little evidence of positive selection at amino acid F1076L in global isolates to be promoted as a possible marker for CQ resistance. Population genetic analysis clearly divided the parasites into eastern and western populations, which is consistent with their geographical separation by the central malaria-free area of Thailand. With CQ-primaquine remaining as the frontline treatment for vivax malaria in all regions of Thailand, such a population subdivision could be shaped and affected by the current drugs for P. falciparum since mixed P. falciparum/P. vivax infections often occur in this region.
Topics: Antimalarials; Drug Resistance; Genetic Variation; Genetics, Population; Genotype; Haplotypes; Humans; Linkage Disequilibrium; Malaria, Vivax; Monte Carlo Method; Multidrug Resistance-Associated Proteins; Parasitic Sensitivity Tests; Phylogeny; Plasmodium vivax; Polymorphism, Genetic; Protozoan Proteins; Recombination, Genetic; Sequence Analysis, DNA; Thailand
PubMed: 29936038
DOI: 10.1016/j.meegid.2018.06.027 -
Malaria Journal Jul 2010Plasmodium vivax is divided into two subtypes, a dominant form, VK210 and a variant form, VK247. This division is dependent on the amino acid composition of the...
BACKGROUND
Plasmodium vivax is divided into two subtypes, a dominant form, VK210 and a variant form, VK247. This division is dependent on the amino acid composition of the circumsporozoite (CS) protein. In this study, the prevalence of the VK247 variant form of P. vivax was investigated in Myanmar.
METHODS
The existence of malaria parasites in blood samples was determined by microscopic examination, polymerase chain reaction (PCR) and DNA hybridization assays. To test for antibodies against P. vivax and Plasmodium falciparum in blood samples, an indirect immunofluorescence antibody test (IFAT) was performed using asexual blood antigens. An enzyme-linked immunosorbent assay with synthetic VK210 and VK247 antigens was carried out to discriminate between the P. vivax subtypes.
RESULTS
By thick smear examination, 73 (n=100) patients were single infected with P. vivax, one with P. falciparum and 13 with both species. By thin smear, 53 patients were single infected with P. vivax, eight with only P. falciparum and 16 with both. Most of the collected blood samples were shown to be P. vivax positive (n=95) by PCR. All cases that were positive for P. falciparum by PCR (n=43) were also positive for P. vivax. However, 52 cases were single infected with P. vivax. IFAT showed antibody titres from 1:32 to 1:4,096. Additionally, using specific antibodies for VK210 and VK247, ELISA showed that 12 patients had antibodies for only the VK210 subtype, 4 patients had only VK247 subtype antibodies and 21 patients had antibodies for both subtypes. Using a DNA hybridization test, 47 patients were infected with the VK210 type, one patient was infected with VK247 and 23 patients were infected with both subtypes.
CONCLUSIONS
The proportion of the VK247 subtype in Myanmar was 43.1% (n=25) among 58 positive cases by serodiagnosis and 25.6% (n=24) among 94 positive cases by genetic diagnosis. In both diagnostic methods, the infection status of malaria patients is highly diverse with respect to malaria species, and multiple clonal infections are prevalent in Myanmar. Therefore, the complexity of the infection should be considered carefully when diagnosing malaria in Myanmar.
Topics: Antibodies, Protozoan; DNA Probes; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique, Indirect; Genetic Variation; Genotype; Humans; Malaria, Vivax; Molecular Sequence Data; Myanmar; Plasmodium vivax; Polymerase Chain Reaction; Prevalence; Protozoan Proteins; Sequence Analysis, DNA; Seroepidemiologic Studies; Serologic Tests
PubMed: 20615261
DOI: 10.1186/1475-2875-9-195 -
PLoS Neglected Tropical Diseases Jul 2020Plasmodium vivax is the most widespread and difficult to treat cause of human malaria. The development of vaccines against the blood stages of P. vivax remains a key...
Plasmodium vivax is the most widespread and difficult to treat cause of human malaria. The development of vaccines against the blood stages of P. vivax remains a key objective for the control and elimination of vivax malaria. Erythrocyte binding-like (EBL) protein family members such as Duffy binding protein (PvDBP) are of critical importance to erythrocyte invasion and have been the major target for vivax malaria vaccine development. In this study, we focus on another member of EBL protein family, P. vivax erythrocyte binding protein (PvEBP). PvEBP was first identified in Cambodian (C127) field isolates and has subsequently been showed its preferences for binding reticulocytes which is directly inhibited by antibodies. We analysed PvEBP sequence from 316 vivax clinical isolates from eight countries including China (n = 4), Ethiopia (n = 24), Malaysia (n = 53), Myanmar (n = 10), Papua New Guinea (n = 16), Republic of Korea (n = 10), Thailand (n = 174), and Vietnam (n = 25). PvEBP gene exhibited four different phenotypic clusters based on the insertion/deletion (indels) variation. PvEBP-RII (179-479 aa.) showed highest polymorphism similar to other EBL family proteins in various Plasmodium species. Whereas even though PvEBP-RIII-V (480-690 aa.) was the most conserved domain, that showed strong neutral selection pressure for gene purifying with significant population expansion. Antigenicity of both of PvEBP-RII (16.1%) and PvEBP-RIII-V (21.5%) domains were comparatively lower than other P. vivax antigen which expected antigens associated with merozoite invasion. Total IgG recognition level of PvEBP-RII was stronger than PvEBP-RIII-V domain, whereas total IgG inducing level was stronger in PvEBP-RIII-V domain. These results suggest that PvEBP-RII is mainly recognized by natural IgG for innate protection, whereas PvEBP-RIII-V stimulates IgG production activity by B-cell for acquired immunity. Overall, the low antigenicity of both regions in patients with vivax malaria likely reflects genetic polymorphism for strong positive selection in PvEBP-RII and purifying selection in PvEBP-RIII-V domain. These observations pose challenging questions to the selection of EBP and point out the importance of immune pressure and polymorphism required for inclusion of PvEBP as a vaccine candidate.
Topics: Amino Acid Sequence; Antibodies, Protozoan; Asia; Genetic Variation; Humans; Immunity, Humoral; Malaria, Vivax; Plasmodium vivax; Polymorphism, Genetic; Protozoan Proteins; Selection, Genetic; Sequence Alignment
PubMed: 32645098
DOI: 10.1371/journal.pntd.0008202 -
Biochemical and Biophysical Research... Mar 2006Rhoptries are cellular organelles localized at the apical pole of apicomplexan parasites. Their content is rich in lipids and proteins that are released during target...
Rhoptries are cellular organelles localized at the apical pole of apicomplexan parasites. Their content is rich in lipids and proteins that are released during target cell invasion. Plasmodium falciparum rhoptry-associated protein 1 (RAP1) has been the most widely studied among this parasite species' rhoptry proteins and is considered to be a good anti-malarial vaccine candidate since it displays little polymorphism and induces antibodies in infected humans. Monoclonal antibodies directed against RAP1 are also able to inhibit target cell invasion in vitro and protection against P. falciparum experimental challenge is induced when non-human primates are immunized with this protein expressed in its recombinant form. This study describes identifying and characterizing RAP1 in Plasmodium vivax, the most widespread parasite species causing malaria in humans, producing more than 80 million infections yearly, mainly in Asia and Latin America. This new protein is encoded by a two-exon gene, is proteolytically processed in a similar manner to its falciparum homologue and, as observed by microscopy, the immunofluorescence pattern displayed is suggestive of its rhoptry localization. Further studies evaluating P. vivax RAP1 protective efficacy in non-human primates should be carried out taking into account the relevance that its P. falciparum homologue has as an anti-malarial vaccine candidate.
Topics: Amino Acid Sequence; Animals; Microscopy, Fluorescence; Molecular Sequence Data; Plasmodium vivax; Protozoan Proteins
PubMed: 16458855
DOI: 10.1016/j.bbrc.2006.01.061 -
PLoS Neglected Tropical Diseases Oct 2018The interaction between Plasmodium vivax Duffy binding protein (PvDBP) and Duffy antigen receptor for chemokines (DARC) has been described as critical for the invasion...
The interaction between Plasmodium vivax Duffy binding protein (PvDBP) and Duffy antigen receptor for chemokines (DARC) has been described as critical for the invasion of human reticulocytes, although increasing reports of P. vivax infections in Duffy-negative individuals questions its unique role. To investigate the genetic diversity of the two main protein ligands for reticulocyte invasion, PvDBP and P. vivax Erythrocyte Binding Protein (PvEBP), we analyzed 458 isolates collected in Cambodia and Madagascar from individuals genotyped as Duffy-positive. First, we observed a high proportion of isolates with multiple copies PvEBP from Madagascar (56%) where Duffy negative and positive individuals coexist compared to Cambodia (19%) where Duffy-negative population is virtually absent. Whether the gene amplification observed is responsible for alternate invasion pathways remains to be tested. Second, we found that the PvEBP gene was less diverse than PvDBP gene (12 vs. 33 alleles) but provided evidence for an excess of nonsynonymous mutations with the complete absence of synonymous mutations. This finding reveals that PvEBP is under strong diversifying selection, and confirms the importance of this protein ligand in the invasion process of the human reticulocytes and as a target of acquired immunity. These observations highlight how genomic changes in parasite ligands improve the fitness of P. vivax isolates in the face of immune pressure and receptor polymorphisms.
Topics: Antigens, Protozoan; Cambodia; Cross-Sectional Studies; Genetic Variation; Genotype; Humans; Madagascar; Malaria, Vivax; Plasmodium vivax; Protozoan Proteins; Receptors, Cell Surface
PubMed: 30346980
DOI: 10.1371/journal.pntd.0006555 -
Experimental Parasitology May 2018Plasmodium vivax remains a potential cause of morbidity and mortality for people living where it is endemic. Understanding the regional genetic diversity of P. vivax is...
BACKGROUND
Plasmodium vivax remains a potential cause of morbidity and mortality for people living where it is endemic. Understanding the regional genetic diversity of P. vivax is valuable for studying population dynamics and tracing the origins of parasites. The Plasmodium vivax circumsporozoite gene (PvCSP) is highly polymorphic and has been used previously as a marker in P. vivax population studies. The aim of this study is to investigate the genetic diversity of the PvCSP, to provide more genetic polymorphism data for further studies on P. vivax population structure, and tracking of the origin of clinical cases.
METHODS
Nested PCR and DNA sequencing of the PvCSP were performed to obtain nucleotide sequences of P. vivax isolates collected from Zhejiang province, China, between 2006 and 2014. To investigate the genetic diversity of PvCSP, the nucleotide sequences and amino acid sequences of the PvCSP were analyzed using DNAstar, Mega software and the phylogenetic tree constructed. The relatedness between the polymorphism and infection source were also analyzed using the SPSS software.
RESULTS
The 66 P. vivax isolates collected from Zhejiang province were either indigenous cases or cases imported from different regions of the world. All 66 P. vivax isolates belonged to the VK210 variant. Fourteen different Peptide Repeat Motifs (PRMs) were detected in the Central Repeat Region (CRR) of PvCSP, among which, two PRMs of GDRADGQPA and GDRAAGQPA were widely distributed in all isolates. Several polymorphic characteristics of the VK210 variant were observed, including the insertion sequence of 12 peptides, the frequency of the GGNA repeat, the frequency of the PRMs repeat in CRR, and the frequency of the PRM of GNGAGGQAA repeat, which were indicative for tracking the parasite.
CONCLUSION
This study presents abundant genetic diversity in the PvCSP marker among P. vivax strains around the world. The genetic data are valuable to expand the polymorphism information on P. vivax, which could be helpful for further study on population dynamics and tracking the origin of P. vivax.
Topics: Amino Acid Sequence; Base Sequence; China; Consensus Sequence; Genetic Markers; Genetic Variation; Humans; Malaria, Vivax; Phylogeny; Plasmodium vivax; Polymerase Chain Reaction; Polymorphism, Genetic; Protozoan Proteins; Sequence Alignment; Sequence Analysis, DNA
PubMed: 29526573
DOI: 10.1016/j.exppara.2018.03.001 -
Journal of Tropical Pediatrics Oct 2014
Topics: Animals; Humans; Malaria, Vivax; Plasmodium vivax; Research
PubMed: 25274351
DOI: 10.1093/tropej/fmu053 -
Journal of Vector Borne Diseases Jun 2010Malaria, an ancient human infectious disease caused by five species of Plasmodium, among them Plasmodium vivax is the most widespread human malaria species and causes...
BACKGROUND & OBJECTIVES
Malaria, an ancient human infectious disease caused by five species of Plasmodium, among them Plasmodium vivax is the most widespread human malaria species and causes huge morbidity to its host. Identification of genetic marker to resolve higher genetic diversity for an ancient origin organism is a crucial task. We have analyzed genetic diversity of P. vivax field isolates using highly polymorphic antigen gene merozoite surface protein-3 alpha (msp-3 alpha) and assessed its suitability as high-resolution genetic marker for population genetic studies.
METHODS
27 P. vivax field isolates collected during chloroquine therapeutic efficacy study at Chennai were analyzed for genetic diversity. PCR-RFLP was employed to assess the genetic variations using highly polymorphic antigen gene msp-3 alpha.
RESULTS
We observed three distinct PCR alleles at msp-3 alpha, and among them allele A showed significantly high frequency (53%, chi2 = 8.22, p = 0.001). PCR-RFLP analysis revealed 14 and 17 distinct RFLP patterns for Hha1 and Alu1 enzymes respectively. Further, RFLP analysis revealed that allele A at msp-3 alpha is more diverse in the population compared with allele B and C. Combining Hha1 and Alu1 RFLP patterns revealed 21 distinct genotypes among 22 isolates reflects higher diversity resolution power of msp-3 alpha in the field isolates.
INTERPRETATION & CONCLUSION
P. vivax isolates from Chennai region revealed substantial amount of genetic diversity and comparison of allelic diversity with other antigen genes and microsatellites suggesting that msp-3 alpha could be a high-resolution marker for genetic diversity studies among P. vivax field isolates.
Topics: Antigens, Protozoan; Blood; Genetic Markers; Genetic Variation; Genotype; Humans; Malaria, Vivax; Plasmodium vivax; Polymorphism, Genetic; Protozoan Proteins
PubMed: 20539045
DOI: No ID Found -
Nature Communications 2014Plasmodium vivax is the leading cause of human malaria in Asia and Latin America but is absent from most of central Africa due to the near fixation of a mutation that...
Plasmodium vivax is the leading cause of human malaria in Asia and Latin America but is absent from most of central Africa due to the near fixation of a mutation that inhibits the expression of its receptor, the Duffy antigen, on human erythrocytes. The emergence of this protective allele is not understood because P. vivax is believed to have originated in Asia. Here we show, using a non-invasive approach, that wild chimpanzees and gorillas throughout central Africa are endemically infected with parasites that are closely related to human P. vivax. Sequence analyses reveal that ape parasites lack host specificity and are much more diverse than human parasites, which form a monophyletic lineage within the ape parasite radiation. These findings indicate that human P. vivax is of African origin and likely selected for the Duffy-negative mutation. All extant human P. vivax parasites are derived from a single ancestor that escaped out of Africa.
Topics: Africa; Animals; Asia; Evolution, Molecular; Malaria; Phylogeny; Plasmodium vivax
PubMed: 24557500
DOI: 10.1038/ncomms4346 -
Methods in Molecular Biology (Clifton,... 2015Plasmodium vivax is considered as the most widely distributed human malaria parasite outside Africa. Studies of P. vivax malaria have always been limited due to the lack...
Plasmodium vivax is considered as the most widely distributed human malaria parasite outside Africa. Studies of P. vivax malaria have always been limited due to the lack of continuously in vitro-propagated parasite lines. Due to this limitation, studies on P. vivax have lagged behind that of P. falciparum, which is routinely maintained in in vitro blood-stage culture. This method allows for the short-term ex vivo culture of P. vivax blood stages and as such offers a wealth of opportunities to study the biology of the blood stages of the parasite. In this chapter we describe the in vitro erythrocyte invasion inhibition assay (IIA) for P. vivax, which can be used as a powerful tool for blood-stage vaccine screening. The major challenges of this assay are the purification of schizont-stage parasites and host reticulocytes. The purification methods for both P. vivax schizont-stage parasites and reticulocytes as detailed here have been developed and simplified. The protocols in this chapter have been optimized to ensure that IIA becomes a more feasible and reliable assay.
Topics: Africa; Animals; Erythrocytes; Humans; Malaria, Vivax; Plasmodium vivax; Reticulocytes; Schizonts; Vaccines
PubMed: 26450389
DOI: 10.1007/978-1-4939-2815-6_15