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Clinical Microbiology and Infection :... Dec 2019Parasitic infections are responsible for a significant burden of disease worldwide as a result of international travel and immigration. More accurate diagnostic tools... (Review)
Review
BACKGROUND
Parasitic infections are responsible for a significant burden of disease worldwide as a result of international travel and immigration. More accurate diagnostic tools are necessary in support to parasite control and elimination programmes in endemic regions as well as for rapid case detection in non-endemic areas. Digital PCR (dPCR) is a powerful technology with recent applications in parasitology.
AIMS
This review provides for the first time an overview of dPCR as a novel technology applied to detection of parasitic infections, and highlights the most relevant potential benefits of this assay.
SOURCES
Peer-reviewed literature pertinent to this review based on PubMed, Cochrane and Embase databases as well as laboratory experience of authors.
CONTENT
Among the 86 studies retrieved, 17 used the dPCR applied to parasites belonging to protozoa (8), helminths (8) and arthropods (1) of clinical human interest. dPCR was adopted in four studies, respectively, for Plasmodium and Schistosoma japonicum. dPCR led to clear advantages over quantitative real-time PCR in P. falciparum and spp., and in S. japonicum showing higher sensitivity; and in Cryptosporidium with higher stability to inhibitors from stool. For all parasites, dPCR allows absolute quantitation without the need of a standard curve. Various dPCR platforms were used. A few critical factors need consideration: DNA load, choice of platform and reaction optimization.
IMPLICATIONS
Owing to its sensitivity and quantitative characteristics, dPCR is a potential candidate to become an appealing new method among the molecular technologies for parasite detection and quantitative analysis in the future. In general, it has more applications than genomic DNA detection only, such as quantitation in mixed infections, gene expression and mutation analysis. dPCR should be considered in malaria screening and diagnosis as a complement to routine assays and in schistosomiasis elimination programmes. Standardized strategies and further studies are needed for the integration of dPCR in routine clinical laboratory.
Topics: Animals; Diagnostic Tests, Routine; Humans; Mass Screening; Microfluidic Analytical Techniques; Molecular Diagnostic Techniques; Parasites; Parasitic Diseases; Parasitology; Polymerase Chain Reaction
PubMed: 31226445
DOI: 10.1016/j.cmi.2019.06.009 -
Parasites & Vectors Jul 2020Diarrheal diseases caused by intestinal protozoan parasites are a major food-borne public health problem across the world. Vegetables and fruits provide important... (Review)
Review
Diarrheal diseases caused by intestinal protozoan parasites are a major food-borne public health problem across the world. Vegetables and fruits provide important nutrients and minerals, but are also common sources of some food-borne human pathogenic microorganisms. The contamination of raw vegetables and fruits with human pathogenic parasites are now a global public health threat, despite the health benefits of these foods in non-pharmacological prophylaxes against diseases. A large number of reports have documented the contamination of vegetables or fruits with human pathogenic microorganisms. In this paper, we reviewed the contamination and detection methods of human pathogenic intestinal protozoans that are frequently recovered from raw vegetables and fruits. The protozoan parasites include Cryptosporidium spp., Giardia duodenalis, Cyclospora cayetanensis, Entamoeba spp., Toxoplasma gondii, Balantioides coli, Blastocystis sp., Cystoisospora belli and Enterocytozoon bieneusi. The risk factors involved in the contamination of vegetables and fruits with parasites are also assessed.
Topics: Animals; Blastocystis; Cryptosporidium; Cyclospora; Entamoeba; Enterocytozoon; Food Parasitology; Fruit; Giardia lamblia; Global Health; Humans; Intestinal Diseases, Parasitic; Parasites; Risk Factors; Toxoplasma; Vegetables
PubMed: 32727529
DOI: 10.1186/s13071-020-04255-3 -
Clinical Microbiology and Infection :... Mar 2019Parasitic diseases are one of the world's most devastating and prevalent infections, causing millions of morbidities and mortalities annually. In the past, many of these... (Review)
Review
BACKGROUND
Parasitic diseases are one of the world's most devastating and prevalent infections, causing millions of morbidities and mortalities annually. In the past, many of these infections have been linked predominantly to tropical or subtropical areas. Nowadays, however, climatic and vector ecology changes, a significant increase in international travel, armed conflicts, and migration of humans and animals have influenced the transmission of some parasitic diseases from 'book pages' to reality in developed countries. It has also been noted that many patients who have never travelled to endemic areas suffer from blood-borne infections caused by protozoa. In the light of existing knowledge, this new trend can be explained by the fact that in the process of migration a large number of asymptomatic carriers become a part of the blood bank donor and transplant donor populations. Accurate and rapid diagnosis represents the crucial weapon in the fight against parasitic infections.
AIMS
To review old and new approaches for rapid diagnosis of parasitic infections.
SOURCES
Data for this review were obtained through searches of PubMed using combinations of the following terms: parasitological diagnostics, microscopy, lateral flow assays, immunochromatographic assays, multiplex-PCR, and transplantation.
CONTENT
In this review, we provide a brief account of the advantages and limitations of rapid methods for diagnosis of parasitic diseases and focus our attention on current and future research in this area. The approximate costs associated with the use of different techniques and their applicability in endemic and non-endemic areas are also discussed.
IMPLICATIONS
Microscopy remains the cornerstone of parasitological diagnostics, especially in the field and low-resource settings, and provides epidemiological assessment of parasite burden. However, increased use and availability of point-of-care tests and molecular assays in modern era allow more rapid and accurate diagnoses and increased sensitivity in the identification of parasitic infections.
Topics: Animals; Diagnostic Tests, Routine; Humans; Microscopy; Molecular Diagnostic Techniques; Parasites; Parasitic Diseases; Parasitology; Point-of-Care Testing
PubMed: 29730224
DOI: 10.1016/j.cmi.2018.04.028 -
Current Opinion in Microbiology Dec 2020
Topics: Animals; Host-Parasite Interactions; Humans; Immunity; Parasites; Parasitic Diseases
PubMed: 33328088
DOI: 10.1016/j.mib.2020.11.008 -
Parasite Immunology Nov 2014
Topics: Animals; Ectoparasitic Infestations; Host-Parasite Interactions; Humans; Parasites; Vaccines
PubMed: 25520973
DOI: 10.1111/pim.12154 -
Nature Microbiology Jul 2023For Plasmodium falciparum, the most widespread and virulent malaria parasite that infects humans, persistence depends on continuous asexual replication in red blood...
For Plasmodium falciparum, the most widespread and virulent malaria parasite that infects humans, persistence depends on continuous asexual replication in red blood cells, while transmission to their mosquito vector requires asexual blood-stage parasites to differentiate into non-replicating gametocytes. This decision is controlled by stochastic derepression of a heterochromatin-silenced locus encoding AP2-G, the master transcription factor of sexual differentiation. The frequency of ap2-g derepression was shown to be responsive to extracellular phospholipid precursors but the mechanism linking these metabolites to epigenetic regulation of ap2-g was unknown. Through a combination of molecular genetics, metabolomics and chromatin profiling, we show that this response is mediated by metabolic competition for the methyl donor S-adenosylmethionine between histone methyltransferases and phosphoethanolamine methyltransferase, a critical enzyme in the parasite's pathway for de novo phosphatidylcholine synthesis. When phosphatidylcholine precursors are scarce, increased consumption of SAM for de novo phosphatidylcholine synthesis impairs maintenance of the histone methylation responsible for silencing ap2-g, increasing the frequency of derepression and sexual differentiation. This provides a key mechanistic link that explains how LysoPC and choline availability can alter the chromatin status of the ap2-g locus controlling sexual differentiation.
Topics: Animals; Humans; Parasites; Histones; Sex Differentiation; Methylation; Epigenesis, Genetic; Malaria; Chromatin; Phosphatidylcholines; Phospholipids
PubMed: 37277533
DOI: 10.1038/s41564-023-01396-w -
Research in Veterinary Science May 2021Parasites, including helminths and protists, are pathogens responsible for waterborne and foodborne illnesses in both developed and developing countries. Their global...
Parasites, including helminths and protists, are pathogens responsible for waterborne and foodborne illnesses in both developed and developing countries. Their global incidence is difficult to estimate, but the World Health Organization (WHO) has indicated the global disease burden of 11 waterborne and foodborne parasitic diseases, is responsible for causing over 407 million illnesses resulting in an estimated of 94 K deaths and 11 million disability-adjusted life years (DALYs). Nevertheless, compared with bacteria and viruses, parasites are often overlooked as etiological agents of foodborne or waterborne disease; this is due to a variety of reasons, including the difficulty of their identification in environmental matrices and because many have a prolonged period between infection and symptoms, making it difficult to implicate infection vehicles. This Special Issue comprises 17 articles that include the more significant waterborne and foodborne parasites of zoonotic importance due to their relevance, with all groups of parasites (protist, cestodes, trematodes, and nematodes) being represented. Each chapter covers relevant aspects regarding -the importance of the parasite in food and water, including an overview of outbreaks where relevant, information on fundamental epidemiological aspects such as transmission, lifecycle and host range, clinical aspects such as pathogenesis, diagnosis and treatment, a summary of prospects for control in water or the food chain, and, finally, providing the authors' opinions regarding future research or studies required to improve control of transmission to people via food or water.
Topics: Animals; Disease Outbreaks; Food Parasitology; Foodborne Diseases; Humans; Incidence; Parasites; Parasitic Diseases, Animal; Veterinarians; Water; Zoonoses
PubMed: 33684793
DOI: 10.1016/j.rvsc.2021.02.020 -
Turkiye Parazitolojii Dergisi Jun 2020MicroRNAs (miRNAs), as epigenetic regulators, are small non-coding RNAs regulating gene expression in eukaryotes at the post-transcriptional level to control biological... (Review)
Review
MicroRNAs (miRNAs), as epigenetic regulators, are small non-coding RNAs regulating gene expression in eukaryotes at the post-transcriptional level to control biological functions. MicroRNAs play a role in development, physiology, infection, immunity and the complex life cycles of parasites. Also, parasite infection can alter host miRNA expression that might result in either parasite clearance or infection. Over the past 20 years, thousands of miRNAs have been identified in the nematode and other parasites. Thus, miRNA pathways are potential targets for the diagnostic and therapeutic control of parasitic diseases. Here, we review the current status and potential functions of miRNAs related to protozoans, helminths, and arthropods.
Topics: Animals; Arthropods; Caenorhabditis elegans; Helminths; Humans; MicroRNAs; Parasites; Parasitic Diseases; RNA, Protozoan
PubMed: 32482043
DOI: 10.4274/tpd.galenos.2020.6776 -
Trends in Parasitology May 2021Protozoan parasites acquire essential ions, nutrients, and other solutes from their insect and vertebrate hosts by transmembrane uptake. For intracellular stages, these... (Review)
Review
Protozoan parasites acquire essential ions, nutrients, and other solutes from their insect and vertebrate hosts by transmembrane uptake. For intracellular stages, these solutes must cross additional membranous barriers. At each step, ion channels and transporters mediate not only this uptake but also the removal of waste products. These transport proteins are best isolated and studied with patch-clamp, but these methods remain accessible to only a few parasitologists due to specialized instrumentation and the required training in both theory and practice. Here, we provide an overview of patch-clamp, describing the advantages and limitations of the technology and highlighting issues that may lead to incorrect conclusions. We aim to help non-experts understand and critically assess patch-clamp data in basic research studies.
Topics: Animals; Biological Transport; Cell Membrane; Eukaryota; Parasites; Parasitology; Patch-Clamp Techniques
PubMed: 33640269
DOI: 10.1016/j.pt.2021.02.002 -
Parasite Immunology Jun 2019Brazil is a middle-income country undergoing the epidemiological transition. Effects of changes in daily life habits and access to clean water, sanitation and urban... (Review)
Review
Brazil is a middle-income country undergoing the epidemiological transition. Effects of changes in daily life habits and access to clean water, sanitation and urban services on a growing urban population have contributed to a double burden of both infectious and noncommunicable chronic diseases. Studies have indicated that parasite infections may modulate the human immune system and influence the development of allergic conditions such as asthma. However, there is no consensus in the published literature on the effects of parasitic infections on allergy, perhaps as a consequence of factors determining the epidemiology of these infections that vary between populations such as age of first infection, duration and chronicity of infections, parasite burden and species, and host genetic susceptibility. In this review, we discuss the observations from Brazil concerning the relationship between parasite infections and allergy.
Topics: Animals; Brazil; Humans; Hypersensitivity; Observational Studies as Topic; Parasites; Parasitic Diseases
PubMed: 30188574
DOI: 10.1111/pim.12588