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Pathogens and Global Health May 2015
Topics: DNA, Protozoan; Disease Eradication; Genetic Variation; Host-Parasite Interactions; Humans; Linkage Disequilibrium; Malaria, Vivax; Molecular Diagnostic Techniques; Molecular Epidemiology; Plasmodium vivax
PubMed: 25943154
DOI: 10.1179/2047772415Z.000000000263 -
The Journal of Infectious Diseases Oct 2021Plasmodium vivax malaria was thought to be rare in Africa, but an increasing number of P. vivax cases reported across Africa and in Duffy-negative individuals challenges...
Plasmodium vivax malaria was thought to be rare in Africa, but an increasing number of P. vivax cases reported across Africa and in Duffy-negative individuals challenges this dogma. The genetic characteristics of P. vivax in Duffy-negative infections, the transmission of P. vivax in East Africa, and the impact of environments on transmission remain largely unknown. This study examined genetic and transmission features of P. vivax from 107 Duffy-negative and 305 Duffy-positive individuals in Ethiopia and Sudan. No clear genetic differentiation was found in P. vivax between the 2 Duffy groups, indicating between-host transmission. P. vivax from Ethiopia and Sudan showed similar genetic clusters, except samples from Khartoum, possibly due to distance and road density that inhibited parasite gene flow. This study is the first to show that P. vivax can transmit to and from Duffy-negative individuals and provides critical insights into the spread of P. vivax in sub-Saharan Africa.
Topics: Africa, Eastern; Duffy Blood-Group System; Erythrocytes; Gene Pool; Genetic Variation; Humans; Malaria, Vivax; Plasmodium vivax; Receptors, Cell Surface; Sudan
PubMed: 33534886
DOI: 10.1093/infdis/jiab063 -
Malaria Journal Oct 2018Presently, many malaria-endemic countries in the world are transitioning towards malaria elimination. Out of the 105 countries with ongoing malaria transmission, 10... (Review)
Review
Presently, many malaria-endemic countries in the world are transitioning towards malaria elimination. Out of the 105 countries with ongoing malaria transmission, 10 countries are classified as being in the pre-elimination phase of malaria control, and 9 countries are in the malaria elimination stage, whereas 7 countries are classified as being in the prevention of introduction phase. Between 2000 and 2015, 17 countries eliminated malaria (i.e., attained zero indigenous cases for 3 years or more). Seven countries were certified by the WHO as having successfully eliminated malaria. The purpose of this review was to analyse the epidemiological characteristics of vivax malaria during the various stages of malaria eradication (elimination) programmes in different countries in the past and present. Experiences of the republics of the former USSR with malaria are interesting, particularly since the data overwhelmingly were published in Russian and might not be known to western readers. Among the most important characteristics of Plasmodium vivax epidemiology at present are changes in the ratio of the short-incubation P. vivax to long-incubation P. vivax, the incidence of severe P. vivax cases, the increased numbers of asymptomatic P. vivax cases, the reduced response to anti-malarials and a few others. Various factors contributing towards the peculiarities of P. vivax epidemiology are discussed.
Topics: Disease Eradication; Malaria, Vivax; Plasmodium vivax; USSR
PubMed: 30286752
DOI: 10.1186/s12936-018-2495-y -
Current Opinion in Microbiology Dec 2018Plasmodium vivax is uniquely restricted to invading reticulocytes, the youngest of red blood cells. Parasite invasion relies on the sequential deployment of multiple... (Review)
Review
Plasmodium vivax is uniquely restricted to invading reticulocytes, the youngest of red blood cells. Parasite invasion relies on the sequential deployment of multiple parasite invasion ligands. Correct targeting of the host reticulocyte is mediated by two families of invasion ligands: the reticulocyte binding proteins (RBPs) and erythrocyte binding proteins (EBPs). The Duffy receptor has long been established as a key determinant for P. vivax invasion. However, recently, the RBP protein PvRBP2b has been shown to bind to transferrin receptor, which is expressed on reticulocytes but lost on normocytes, implicating the ligand-receptor in the reticulocyte tropism of P. vivax. Furthermore there is increasing evidence for P. vivax growth and sexual development in reticulocyte-enriched tissues such as the bone marrow.
Topics: Animals; Host-Parasite Interactions; Humans; Malaria, Vivax; Plasmodium vivax; Protozoan Proteins; Reticulocytes; Tropism
PubMed: 30366310
DOI: 10.1016/j.mib.2018.10.002 -
Memorias Do Instituto Oswaldo Cruz Aug 2011It is generally accepted that Plasmodium vivax, the most widely distributed human malaria parasite, causes mild disease and that this species does not sequester in the... (Review)
Review
It is generally accepted that Plasmodium vivax, the most widely distributed human malaria parasite, causes mild disease and that this species does not sequester in the deep capillaries of internal organs. Recent evidence, however, has demonstrated that there is severe disease, sometimes resulting in death, exclusively associated with P. vivax and that P. vivax-infected reticulocytes are able to cytoadhere in vitro to different endothelial cells and placental cryosections. Here, we review the scarce and preliminary data on cytoadherence in P. vivax, reinforcing the importance of this phenomenon in this species and highlighting the avenues that it opens for our understanding of the pathology of this neglected human malaria parasite.
Topics: Cell Adhesion; Erythrocytes; Humans; Malaria, Vivax; Plasmodium vivax
PubMed: 21881760
DOI: 10.1590/s0074-02762011000900010 -
PLoS Neglected Tropical Diseases Mar 2020More than 200 million malaria clinical cases are reported each year due to Plasmodium vivax, the most widespread Plasmodium species in the world. This species has been...
More than 200 million malaria clinical cases are reported each year due to Plasmodium vivax, the most widespread Plasmodium species in the world. This species has been neglected and understudied for a long time, due to its lower mortality in comparison with Plasmodium falciparum. A renewed interest has emerged in the past decade with the discovery of antimalarial drug resistance and of severe and even fatal human cases. Nonetheless, today there are still significant gaps in our understanding of the population genetics and evolutionary history of P. vivax, particularly because of a lack of genetic data from Africa. To address these gaps, we genotyped 14 microsatellite loci in 834 samples obtained from 28 locations in 20 countries from around the world. We discuss the worldwide population genetic structure and diversity and the evolutionary origin of P. vivax in the world and its introduction into the Americas. This study demonstrates the importance of conducting genome-wide analyses of P. vivax in order to unravel its complex evolutionary history.
Topics: Genetic Variation; Genotype; Genotyping Techniques; Global Health; Humans; Malaria, Vivax; Plasmodium vivax
PubMed: 32150544
DOI: 10.1371/journal.pntd.0008072 -
Malaria Journal Oct 2011Plasmodium vivax is a major cause of febrile illness in endemic areas of Asia, Central and South America, and the horn of Africa. Plasmodium vivax infections are... (Review)
Review
Plasmodium vivax is a major cause of febrile illness in endemic areas of Asia, Central and South America, and the horn of Africa. Plasmodium vivax infections are characterized by relapses of malaria arising from persistent liver stages of the parasite (hypnozoites) which can be prevented only by 8-aminoquinoline anti-malarials. Tropical P. vivax relapses at three week intervals if rapidly eliminated anti-malarials are given for treatment, whereas in temperate regions and parts of the sub-tropics P. vivax infections are characterized either by a long incubation or a long-latency period between illness and relapse - in both cases approximating 8-10 months. The epidemiology of the different relapse phenotypes has not been defined adequately despite obvious relevance to malaria control and elimination. The number of sporozoites inoculated by the anopheline mosquito is an important determinant of both the timing and the number of relapses. The intervals between relapses display a remarkable periodicity which has not been explained. Evidence is presented that the proportion of patients who have successive relapses is relatively constant and that the factor which activates hypnozoites and leads to regular interval relapse in vivax malaria is the systemic febrile illness itself. It is proposed that in endemic areas a large proportion of the population harbours latent hypnozoites which can be activated by a systemic illness such as vivax or falciparum malaria. This explains the high rates of vivax following falciparum malaria, the high proportion of heterologous genotypes in relapses, the higher rates of relapse in people living in endemic areas compared with artificial infection studies, and, by facilitating recombination between different genotypes, contributes to P. vivax genetic diversity particularly in low transmission settings. Long-latency P. vivax phenotypes may be more widespread and more prevalent than currently thought. These observations have important implications for the assessment of radical treatment efficacy and for malaria control and elimination.
Topics: Humans; Liver; Malaria, Vivax; Models, Biological; Periodicity; Plasmodium vivax; Recurrence; Time Factors
PubMed: 21989376
DOI: 10.1186/1475-2875-10-297 -
Proteomics. Clinical Applications Jul 2018Plasmodium vivax is a protozoan parasite that is one of the causative agents of human malaria. Due to several occult features of its life cycle, P. vivax threatens to be... (Review)
Review
Plasmodium vivax is a protozoan parasite that is one of the causative agents of human malaria. Due to several occult features of its life cycle, P. vivax threatens to be a problem for the recent efforts toward elimination of malaria globally. With an emphasis on malaria elimination goals, the authors summarize the major gaps in P. vivax diagnosis and describe how proteomics technologies have begun to contribute toward the discovery of antigens that could be used for various technology platforms and applications. The authors suggest areas where, in the future, proteomics technologies could fill in gaps in P. vivax diagnosis that have proved difficult. The discovery of new parasite antigens, host responses, and immune signatures using proteomics technologies will be a key part of the global malaria elimination efforts.
Topics: Humans; India; Malaria, Vivax; Plasmodium vivax; Proteome; Proteomics; Protozoan Proteins
PubMed: 29193853
DOI: 10.1002/prca.201700024 -
Infection, Genetics and Evolution :... Sep 2021The polymorphic nature of merozoite surface protein 1(MSP1) raises doubts whether it may serve as a vaccine target against Plasmodium vivax malaria. This study analyses...
The polymorphic nature of merozoite surface protein 1(MSP1) raises doubts whether it may serve as a vaccine target against Plasmodium vivax malaria. This study analyses the impact of genetic variability on the epitope organization of different Pvmsp1 blocks. Ten blood samples collected from P. vivax infected malaria patients from West Bengal, India were used to analyze sequence and antigenic diversities of block 2 region of Pvmsp1. An additional 48 block 2 sequences from other countries were also analyzed. Global genetic framework of Pvmsp1 block 2 was represented by 12 indel clusters & 33 haplotypes (haplotype diversiy = 0.965 ± 0.024). Parasite sequences pertaining to other Pvmsp1 modules, namely block 6 and 10 displayed 14 & 29 (haplotype diversiy = 0.975 ± 0.003) and 22 & 30 indel clusters and haplotypes (haplotype diversiy = 0.947 ± 0.004), respectively. In spite of this remarkable genetic diversity, a small number of conserved epitopes were detected in all three PvMSP1 blocks. This novel finding substantiates that MSP1 could serve as a promising vaccine candidate against vivax malaria.
Topics: Epitopes, B-Lymphocyte; Genetic Variation; Malaria Vaccines; Merozoite Surface Protein 1; Plasmodium vivax
PubMed: 34022438
DOI: 10.1016/j.meegid.2021.104929 -
BMC Systems Biology Jan 2019The lack of a continuous long-term in vitro culture system for Plasmodium vivax severely limits our knowledge of pathophysiology of the most widespread malaria parasite....
BACKGROUND
The lack of a continuous long-term in vitro culture system for Plasmodium vivax severely limits our knowledge of pathophysiology of the most widespread malaria parasite. To gain direct understanding of P. vivax human infections, we used Next Generation Sequencing data mining to unravel parasite in vivo expression profiles for P. vivax, and P. falciparum as comparison.
RESULTS
We performed cloud and local computing to extract parasite transcriptomes from publicly available raw data of human blood samples. We developed a Poisson Modelling (PM) method to confidently identify parasite derived transcripts in mixed RNAseq signals of infected host tissues. We successfully retrieved and reconstructed parasite transcriptomes from infected patient blood as early as the first blood stage cycle; and the same methodology did not recover any significant signal from controls. Surprisingly, these first generation blood parasites already show strong signature of transmission, which indicates the commitment from asexual-to-sexual stages. Further, we place the results within the context of P. vivax's complex life cycle, by developing mathematical models for P. vivax and P. falciparum and using sensitivity analysis assess the relative epidemiological impact of possible early stage transmission.
CONCLUSION
The study uncovers the earliest onset of P. vivax blood pathogenesis and highlights the challenges of P. vivax eradication programs.
Topics: Blood; Gametogenesis; Gene Expression Profiling; Humans; Malaria, Vivax; Models, Biological; Plasmodium vivax; RNA, Messenger
PubMed: 30634978
DOI: 10.1186/s12918-018-0669-4