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Journal of Clinical Microbiology Dec 2004There have been reports of increasing numbers of cases of malaria among migrants and travelers. Although microscopic examination of blood smears remains the "gold... (Comparative Study)
Comparative Study
There have been reports of increasing numbers of cases of malaria among migrants and travelers. Although microscopic examination of blood smears remains the "gold standard" in diagnosis, this method suffers from insufficient sensitivity and requires considerable expertise. To improve diagnosis, a multiplex real-time PCR was developed. One set of generic primers targeting a highly conserved region of the 18S rRNA gene of the genus Plasmodium was designed; the primer set was polymorphic enough internally to design four species-specific probes for P. falciparum, P. vivax, P. malarie, and P. ovale. Real-time PCR with species-specific probes detected one plasmid copy of P. falciparum, P. vivax, P. malariae, and P. ovale specifically. The same sensitivity was achieved for all species with real-time PCR with the 18S screening probe. Ninety-seven blood samples were investigated. For 66 of them (60 patients), microscopy and real-time PCR results were compared and had a crude agreement of 86% for the detection of plasmodia. Discordant results were reevaluated with clinical, molecular, and sequencing data to resolve them. All nine discordances between 18S screening PCR and microscopy were resolved in favor of the molecular method, as were eight of nine discordances at the species level for the species-specific PCR among the 31 samples positive by both methods. The other 31 blood samples were tested to monitor the antimalaria treatment in seven patients. The number of parasites measured by real-time PCR fell rapidly for six out of seven patients in parallel to parasitemia determined microscopically. This suggests a role of quantitative PCR for the monitoring of patients receiving antimalaria therapy.
Topics: Animals; DNA, Protozoan; Humans; Malaria; Plasmodium; Plasmodium falciparum; Plasmodium malariae; Plasmodium ovale; Plasmodium vivax; Polymerase Chain Reaction; RNA, Ribosomal, 18S; Sensitivity and Specificity; Species Specificity
PubMed: 15583293
DOI: 10.1128/JCM.42.12.5636-5643.2004 -
Malaria Journal May 2022Malaria is a vector-borne disease caused by protozoan parasites of the genus Plasmodium. Plasmodium vivax is the most prevalent human-infecting species in the Americas.... (Review)
Review
Malaria is a vector-borne disease caused by protozoan parasites of the genus Plasmodium. Plasmodium vivax is the most prevalent human-infecting species in the Americas. However, the origins of this parasite in this continent are still debated. Similarly, it is now accepted that the existence of Plasmodium simium is explained by a P. vivax transfer from humans to monkey in America. However, many uncertainties still exist concerning the origin of the transfer and whether several transfers occurred. In this review, the most recent studies that addressed these questions using genetic and genomic approaches are presented.
Topics: Biological Evolution; Genome; Humans; Malaria; Plasmodium; Plasmodium vivax
PubMed: 35505431
DOI: 10.1186/s12936-022-04132-7 -
Memorias Do Instituto Oswaldo Cruz Aug 2014Metabolomics uses high-resolution mass spectrometry to provide a chemical fingerprint of thousands of metabolites present in cells, tissues or body fluids. Such... (Review)
Review
Metabolomics uses high-resolution mass spectrometry to provide a chemical fingerprint of thousands of metabolites present in cells, tissues or body fluids. Such metabolic phenotyping has been successfully used to study various biologic processes and disease states. High-resolution metabolomics can shed new light on the intricacies of host-parasite interactions in each stage of the Plasmodium life cycle and the downstream ramifications on the host's metabolism, pathogenesis and disease. Such data can become integrated with other large datasets generated using top-down systems biology approaches and be utilised by computational biologists to develop and enhance models of malaria pathogenesis relevant for identifying new drug targets or intervention strategies. Here, we focus on the promise of metabolomics to complement systems biology approaches in the quest for novel interventions in the fight against malaria. We introduce the Malaria Host-Pathogen Interaction Center (MaHPIC), a new systems biology research coalition. A primary goal of the MaHPIC is to generate systems biology datasets relating to human and non-human primate (NHP) malaria parasites and their hosts making these openly available from an online relational database. Metabolomic data from NHP infections and clinical malaria infections from around the world will comprise a unique global resource.
Topics: Animals; Computational Biology; Host-Parasite Interactions; Humans; Malaria; Mass Spectrometry; Metabolomics; Plasmodium
PubMed: 25185001
DOI: 10.1590/0074-0276140043 -
Proceedings of the National Academy of... Mar 20225-methylcytosine (mC) is an important epitranscriptomic modification involved in messenger RNA (mRNA) stability and translation efficiency in various biological...
5-methylcytosine (mC) is an important epitranscriptomic modification involved in messenger RNA (mRNA) stability and translation efficiency in various biological processes. However, it remains unclear if mC modification contributes to the dynamic regulation of the transcriptome during the developmental cycles of parasites. Here, we characterize the landscape of mC mRNA modifications at single nucleotide resolution in the asexual replication stages and gametocyte sexual stages of rodent () and human () malaria parasites. While different representations of mC-modified mRNAs are associated with the different stages, the abundance of the mC marker is strikingly enhanced in the transcriptomes of gametocytes. Our results show that mC modifications confer stability to the transcripts and that a ortholog of NSUN2 is a major mRNA mC methyltransferase in malaria parasites. Upon knockout of (), marked reductions of mC modification were observed in a panel of gametocytogenesis-associated transcripts. These reductions correlated with impaired gametocyte production in the knockout rodent malaria parasites. Restoration of the gene in the knockout parasites rescued the gametocyte production phenotype as well as mC modification of the gametocytogenesis-associated transcripts. Together with the mRNA mC profiles for two species of , our findings demonstrate a major role for NSUN2-mediated mC modifications in mRNA transcript stability and sexual differentiation in malaria parasites.
Topics: 5-Methylcytosine; Germ Cells; Plasmodium falciparum; Plasmodium yoelii; Protozoan Proteins; RNA, Messenger; Transcriptome
PubMed: 35210361
DOI: 10.1073/pnas.2110713119 -
Cellular Microbiology May 2014The malaria parasite Plasmodium utilizes specialized proteins for adherence to cellular receptors in its mosquito vector and human host. Adherence is critical for... (Review)
Review
The malaria parasite Plasmodium utilizes specialized proteins for adherence to cellular receptors in its mosquito vector and human host. Adherence is critical for parasite development, host cell traversal and invasion, and protection from vector and host immune mechanisms. These vital roles have identified several adhesins as vaccine candidates. A deficiency in current adhesin-based vaccines is induction of antibodies targeting non-conserved, non-functional and decoy epitopes due to the use of full length proteins or binding domains. To alleviate the elicitation of non-inhibitory antibodies, conserved functional regions of proteins must be identified and exploited. Structural biology provides the tools necessary to achieve this goal, and has succeeded in defining biologically functional receptor binding and oligomerization interfaces for a number of promising malaria vaccine candidates. We describe here the current knowledge of Plasmodium adhesin structure and function, and how it has illuminated elements of parasite biology and defined interactions at the host/vector and parasite interface.
Topics: Cell Adhesion; Cell Adhesion Molecules; Humans; Plasmodium; Protozoan Proteins
PubMed: 24506585
DOI: 10.1111/cmi.12276 -
The Lancet. Infectious Diseases Oct 2021
Topics: Antimalarials; Clinical Trials as Topic; Female; Humans; Infant; Malaria; Malaria Vaccines; Male; Plasmodium; Vaccination
PubMed: 34562396
DOI: 10.1016/S1473-3099(21)00569-7 -
Trends in Parasitology Jun 2007Although Plasmodium malariae was first described as an infectious disease of humans by Golgi in 1886 and Plasmodium ovale identified by Stevens in 1922, there are still... (Review)
Review
Although Plasmodium malariae was first described as an infectious disease of humans by Golgi in 1886 and Plasmodium ovale identified by Stevens in 1922, there are still large gaps in our knowledge of the importance of these infections as causes of malaria in different parts of the world. They have traditionally been thought of as mild illnesses that are caused by rare and, in case of P. ovale, short-lived parasites. However, recent advances in sensitive PCR diagnosis are causing a re-evaluation of this assumption. Low-level infection seems to be common across malaria-endemic areas, often as complex mixed infections. The potential interactions of P. malariae and P. ovale with Plasmodium falciparum and Plasmodium vivax might explain some basic questions of malaria epidemiology, and understanding these interactions could have an important influence on the deployment of interventions such as malaria vaccines.
Topics: Adolescent; Adult; Animals; Child; Child, Preschool; Humans; Infant; Infant, Newborn; Malaria; Microscopy; Plasmodium malariae; Plasmodium ovale; Polymerase Chain Reaction; Prevalence
PubMed: 17459775
DOI: 10.1016/j.pt.2007.04.009 -
Frontiers in Cellular and Infection... 2018Malaria, a disease caused by parasites, is widespread throughout tropical and sub-tropical regions worldwide; it mostly affects children and pregnant woman. Eradication... (Review)
Review
Malaria, a disease caused by parasites, is widespread throughout tropical and sub-tropical regions worldwide; it mostly affects children and pregnant woman. Eradication has stalled despite effective prevention measures and medication being available for this disease; this has mainly been due to the parasite's resistance to medical treatment and the mosquito vector's resistance to insecticides. Tackling such resistance involves using renewed approaches and techniques for accruing a deep understanding of the parasite's biology, and developing new drugs and vaccines. Studying the parasite's invasion of erythrocytes should shed light on its ability to switch between invasion phenotypes related to the expression of gene sets encoding proteins acting as ligands during target cell invasion, thereby conferring mechanisms for evading a particular host's immune response and adapting to changes in target cell surface receptors. This review considers some factors influencing the expression of such phenotypes, such as 's genetic, transcriptional and epigenetic characteristics, and explores some host-related aspects which could affect parasite phenotypes, aiming at integrating knowledge regarding this topic and the possible relationship between the parasite's biology and host factors playing a role in erythrocyte invasion.
Topics: Endocytosis; Erythrocytes; Gene Expression Regulation; Host-Pathogen Interactions; Humans; Plasmodium falciparum
PubMed: 30693273
DOI: 10.3389/fcimb.2018.00454 -
Briefings in Functional Genomics Sep 2019Two simian malaria parasite species, Plasmodium knowlesi and Plasmodium cynomolgi, cause zoonotic infections in Southeast Asia, and they have therefore gained... (Review)
Review
Two simian malaria parasite species, Plasmodium knowlesi and Plasmodium cynomolgi, cause zoonotic infections in Southeast Asia, and they have therefore gained recognition among scientists and public health officials. Notwithstanding, these species and others including Plasmodium coatneyi have served for decades as sources of knowledge on the biology, genetics and evolution of Plasmodium, and the diverse ramifications and outcomes of malaria in their monkey hosts. Experimental analysis of these species can help to fill gaps in knowledge beyond what may be possible studying the human malaria parasites or rodent parasite species. The genome sequences for these simian malaria parasite species were reported during the last decade, and functional genomics research has since been pursued. Here research on the functional genomics analysis involving these species is summarized and their importance is stressed, particularly for understanding host-parasite interactions, and potentially testing novel interventions. Importantly, while Plasmodium falciparum and Plasmodium vivax can be studied in small New World monkeys, the simian malaria parasites can be studied more effectively in the larger Old World monkey macaque hosts, which are more closely related to humans. In addition to ex vivo analyses, experimental scenarios can include passage through Anopheline mosquito hosts and longitudinal infections in monkeys to study acute and chronic infections, as well as relapses, all in the context of the in vivo host environment. Such experiments provide opportunities for understanding functional genomic elements that govern host-parasite interactions, immunity and pathogenesis in-depth, addressing hypotheses not possible from in vitro cultures or cross-sectional clinical studies with humans.
Topics: Animals; Genomics; Host-Parasite Interactions; Humans; Plasmodium; Plasmodium cynomolgi; Plasmodium falciparum; Plasmodium knowlesi; Plasmodium vivax; Primates; Systems Biology
PubMed: 31241151
DOI: 10.1093/bfgp/elz013 -
The FEBS Journal Sep 2007Malaria is caused by protozoan parasites of the genus Plasmodium and is a major cause of mortality and morbidity worldwide. These parasites have a complex life cycle in... (Review)
Review
Malaria is caused by protozoan parasites of the genus Plasmodium and is a major cause of mortality and morbidity worldwide. These parasites have a complex life cycle in their mosquito vector and vertebrate hosts. The primary factors contributing to the resurgence of malaria are the appearance of drug-resistant strains of the parasite, the spread of insecticide-resistant strains of the mosquito and the lack of licensed malaria vaccines of proven efficacy. This minireview includes a summary of the disease, the life cycle of the parasite, information relating to the genome and proteome of the species lethal to humans, Plasmodium falciparum, together with other recent developments in the field.
Topics: Animals; Culicidae; Erythrocytes; Humans; Malaria; Plasmodium
PubMed: 17824953
DOI: 10.1111/j.1742-4658.2007.05997.x