-
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 -
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 -
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 -
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 -
Parasitology Dec 2022The myxozoan was described from hatchery rainbow trout over 70 years ago. The parasite continues to cause severe disease in salmon and trout, and is recognized as a... (Review)
Review
The myxozoan was described from hatchery rainbow trout over 70 years ago. The parasite continues to cause severe disease in salmon and trout, and is recognized as a barrier to salmon recovery in some rivers. This review incorporates changes in our knowledge of the parasite's life cycle, taxonomy and biology and examines how this information has expanded our understanding of the interactions between and its salmonid and annelid hosts, and how overarching environmental factors affect this host–parasite system. Development of molecular diagnostic techniques has allowed discrimination of differences in parasite genotypes, which have differing host affinities, and enabled the measurement of the spatio-temporal abundance of these different genotypes. Establishment of the life cycle in the laboratory has enabled studies on host–parasite interactions and the availability of transcriptomic data has informed our understanding of parasite virulence factors and host defences. Together, these advances have informed the development of models and management actions to mitigate disease.
Topics: Animals; Parasites; Cnidaria; Parasitic Diseases, Animal; Fish Diseases; Myxozoa; Oncorhynchus mykiss
PubMed: 36081219
DOI: 10.1017/S0031182022001275 -
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 Sep 2021Despite considerable genetic variation within hosts, most parasite genome sequencing studies focus on bulk samples composed of millions of cells. Analysis of bulk... (Review)
Review
Despite considerable genetic variation within hosts, most parasite genome sequencing studies focus on bulk samples composed of millions of cells. Analysis of bulk samples is biased toward the dominant genotype, concealing cell-to-cell variation and rare variants. To tackle this, single-cell sequencing approaches have been developed and tailored to specific host-parasite systems. These are allowing the genetic diversity and kinship in complex parasite populations to be deciphered and for de novo genetic variation to be captured. Here, we outline the methodologies being used for single-cell sequencing of parasitic protozoans, such as Plasmodium and Leishmania spp., and how these tools are being applied to understand parasite biology.
Topics: Eukaryota; Genetic Variation; Genome, Protozoan; Parasitology; Single-Cell Analysis
PubMed: 34172399
DOI: 10.1016/j.pt.2021.05.013 -
Briefings in Functional Genomics Jan 2018Nematodes are highly abundant animals, and many species have a parasitic lifestyle. Nematode parasites are important pathogens of humans and other animals, and there is... (Review)
Review
Nematodes are highly abundant animals, and many species have a parasitic lifestyle. Nematode parasites are important pathogens of humans and other animals, and there is considerable interest in understanding their molecular and genomic adaptations to nematode parasitism. This has been approached in three main ways: comparing the genomes of closely related parasitic and free-living taxa, comparing the gene expression of parasitic and free-living life cycle stages of parasitic nematode species, and analysing the molecules that parasitic nematodes excrete and secrete. To date, these studies show that many species of parasitic nematodes have genomes that have large gene families coding for proteases/peptidases, protease inhibitors, SCP/TAPS proteins and acetylcholinesterases, and in many cases there is evidence that these appear to be used by parasitic stages inside hosts, and are often secreted. Many parasitic nematodes have taxa-restricted gene families that also appear to be involved in parasitism, emphasizing that there is still much to be discovered about what it takes to be a parasitic nematode.
Topics: Animals; Genome; Genomics; Life Cycle Stages; Nematoda; Parasites; Phylogeny
PubMed: 28472353
DOI: 10.1093/bfgp/elx010 -
Parasitology Research Nov 2022Global change in the Anthropocene has modified the environment of almost any species on earth, be it through climate change, habitat modifications, pollution, human... (Review)
Review
Global change in the Anthropocene has modified the environment of almost any species on earth, be it through climate change, habitat modifications, pollution, human intervention in the form of mass drug administration (MDA), or vaccination. This can have far-reaching consequences on all organisational levels of life, including eco-physiological stress at the cell and organism level, individual fitness and behaviour, population viability, species interactions and biodiversity. Host-parasite interactions often require highly adapted strategies by the parasite to survive and reproduce within the host environment and ensure efficient transmission among hosts. Yet, our understanding of the system-level outcomes of the intricate interplay of within host survival and among host parasite spread is in its infancy. We shed light on how global change affects host-parasite interactions at different organisational levels and address challenges and opportunities to work towards better-informed management of parasite control. We argue that global change affects host-parasite interactions in wildlife inhabiting natural environments rather differently than in humans and invasive species that benefit from anthropogenic environments as habitat and more deliberate rather than erratic exposure to therapeutic drugs and other control efforts.
Topics: Animals; Animals, Wild; Biodiversity; Ecosystem; Host-Parasite Interactions; Humans; Parasites
PubMed: 36066742
DOI: 10.1007/s00436-022-07649-7 -
Parasites & Vectors Jun 2021Parasites, including viruses, bacteria, fungi, protists, helminths, and arthropods, are ubiquitous in the animal kingdom. Consequently, hosts are frequently infected... (Review)
Review
Parasites, including viruses, bacteria, fungi, protists, helminths, and arthropods, are ubiquitous in the animal kingdom. Consequently, hosts are frequently infected with more than one parasite species simultaneously. The assessment of such co-infections is of fundamental importance for disease ecology, but relevant studies involving non-domesticated animals have remained scarce. Many amphibians are in decline, and they generally have a highly diverse parasitic fauna. Here we review the literature reporting on field surveys, veterinary case studies, and laboratory experiments on co-infections in amphibians, and we summarize what is known about within-host interactions among parasites, which environmental and intrinsic factors influence the outcomes of these interactions, and what effects co-infections have on hosts. The available literature is piecemeal, and patterns are highly diverse, so that identifying general trends that would fit most host-multiparasite systems in amphibians is difficult. Several examples of additive, antagonistic, neutral, and synergistic effects among different parasites are known, but whether members of some higher taxa usually outcompete and override the effects of others remains unclear. The arrival order of different parasites and the time lag between exposures appear in many cases to fundamentally shape competition and disease progression. The first parasite to arrive can gain a marked reproductive advantage or induce cross-reaction immunity, but by disrupting the skin and associated defences (i.e., skin secretions, skin microbiome) and by immunosuppression, it can also pave the way for subsequent infections. Although there are exceptions, detrimental effects to the host are generally aggravated with increasing numbers of co-infecting parasite species. Finally, because amphibians are ectothermic animals, temperature appears to be the most critical environmental factor that affects co-infections, partly via its influence on amphibian immune function, partly due to its direct effect on the survival and growth of parasites. Besides their importance for our understanding of ecological patterns and processes, detailed knowledge about co-infections is also crucial for the design and implementation of effective wildlife disease management, so that studies concentrating on the identified gaps in our understanding represent rewarding research avenues.
Topics: Amphibians; Animals; Animals, Wild; Coinfection; Host-Parasite Interactions; Parasites; Parasitic Diseases, Animal
PubMed: 34082796
DOI: 10.1186/s13071-021-04796-1