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Trends in Parasitology Sep 2019Although foodborne parasites (FBPs) are becoming recognized as important foodborne pathogens, they remain neglected compared with bacterial and viral foodborne... (Review)
Review
Although foodborne parasites (FBPs) are becoming recognized as important foodborne pathogens, they remain neglected compared with bacterial and viral foodborne pathogens. As drivers for infection with FBPs are variable, it is often unclear for funding bodies where research should be prioritized. Through a COST Action (Euro-FBP; FA1408), we harnessed Europe-wide expertise to address these questions, using an Expert Knowledge Elicitation approach. Eating habits, lack of food-chain control, lack of awareness from relevant agencies, globalization, and water quality were identified as major drivers for FBP infection. Prioritized research needs to be largely focused on methodological gaps, but also on surveillance concerns, impact-assessment issues, and the role of microbiota. Despite the European focus, these responses should be relevant to those concerned with FBPs globally.
Topics: Animals; Europe; Food Parasitology; Foodborne Diseases; Humans; Parasitic Diseases; Research
PubMed: 31358427
DOI: 10.1016/j.pt.2019.07.002 -
Conservation Biology : the Journal of... Aug 2016Parasitic species, which depend directly on host species for their survival, represent a major regulatory force in ecosystems and a significant component of Earth's...
Parasitic species, which depend directly on host species for their survival, represent a major regulatory force in ecosystems and a significant component of Earth's biodiversity. Yet the negative impacts of parasites observed at the host level have motivated a conservation paradigm of eradication, moving us farther from attainment of taxonomically unbiased conservation goals. Despite a growing body of literature highlighting the importance of parasite-inclusive conservation, most parasite species remain understudied, underfunded, and underappreciated. We argue the protection of parasitic biodiversity requires a paradigm shift in the perception and valuation of their role as consumer species, similar to that of apex predators in the mid-20th century. Beyond recognizing parasites as vital trophic regulators, existing tools available to conservation practitioners should explicitly account for the unique threats facing dependent species. We built upon concepts from epidemiology and economics (e.g., host-density threshold and cost-benefit analysis) to devise novel metrics of margin of error and minimum investment for parasite conservation. We define margin of error as the risk of accidental host extinction from misestimating equilibrium population sizes and predicted oscillations, while minimum investment represents the cost associated with conserving the additional hosts required to maintain viable parasite populations. This framework will aid in the identification of readily conserved parasites that present minimal health risks. To establish parasite conservation, we propose an extension of population viability analysis for host-parasite assemblages to assess extinction risk. In the direst cases, ex situ breeding programs for parasites should be evaluated to maximize success without undermining host protection. Though parasitic species pose a considerable conservation challenge, adaptations to conservation tools will help protect parasite biodiversity in the face of an uncertain environmental future.
Topics: Animals; Biodiversity; Conservation of Natural Resources; Ecosystem; Host-Parasite Interactions; Parasites
PubMed: 26400623
DOI: 10.1111/cobi.12634 -
ELife Jul 2023Mermithid nematodes are obligate invertebrate parasites dating back to the Early Cretaceous. Their fossil record is sparse, especially before the Cenozoic, thus little...
Mermithid nematodes are obligate invertebrate parasites dating back to the Early Cretaceous. Their fossil record is sparse, especially before the Cenozoic, thus little is known about their early host associations. This study reports 16 new mermithids associated with their insect hosts from mid-Cretaceous Kachin amber, 12 of which include previously unknown hosts. These fossils indicate that mermithid parasitism of invertebrates was already widespread and played an important role in the mid-Cretaceous terrestrial ecosystem. Remarkably, three hosts (bristletails, barklice, and perforissid planthoppers) were previously unknown to be parasitized by mermithids both past and present. Furthermore, our study shows that in contrast to their Cenozoic counterparts, Cretaceous nematodes including mermithids are more abundant in non-holometabolous insects. This result suggests that nematodes had not completely exploited the dominant Holometabola as their hosts until the Cenozoic. This study reveals what appears to be a vanished history of nematodes that parasitized Cretaceous insects.
Topics: Animals; Mermithoidea; Ecosystem; Nematoda; Insecta; Parasites; Fossils; Amber
PubMed: 37449724
DOI: 10.7554/eLife.86283 -
Parasitology Jan 2022Although it is generally known that a combination of abiotic and biotic drivers shapes the distribution and abundance of parasites, our understanding of the interplay of...
Although it is generally known that a combination of abiotic and biotic drivers shapes the distribution and abundance of parasites, our understanding of the interplay of these factors remains to be assessed for most marine host species. The present field survey investigated spatial patterns of richness, prevalence and abundance of parasites in Mytilus galloprovincialis along the coast of the northern Adriatic Sea. Herein, the relationships between biotic (host size, density and local parasite richness of mussel population) and abiotic (eutrophication and salinity) drivers and parasite richness of mussel individuals, prevalence and abundance were analysed. Local parasite richness was the most relevant factor driving parasite species richness in mussel individuals. Prevalence was mainly driven by eutrophication levels in three out of four parasite species analysed. Similarly, abundance was driven mainly by eutrophication in two parasite species. Mussel size, density and salinity had only minor contributions to the best fitting models. This study highlights that the influence of abiotic and biotic drivers on parasite infections in mussels can be differentially conveyed, depending on the infection measure applied, i.e. parasite richness, prevalence or abundance. Furthermore, it stresses the importance of eutrophication as a major factor influencing parasite prevalence and abundance in mussels in the Adriatic Sea.
Topics: Animals; Humans; Mytilus; Parasites; Parasitic Diseases; Prevalence; Salinity
PubMed: 34380583
DOI: 10.1017/S0031182021001438 -
Indian Journal of Ophthalmology Sep 2023Ophthalmic dirofilariasis is an uncommon zoonotic parasitic infection caused by species of Dirofilaria, a dog tapeworm that is transmitted to human by mosquitoes. Man is...
BACKGROUND
Ophthalmic dirofilariasis is an uncommon zoonotic parasitic infection caused by species of Dirofilaria, a dog tapeworm that is transmitted to human by mosquitoes. Man is a dead-end host for the parasite. Ophthalmic involvement is rare and includes periorbital, subconjunctival, subtenon, and intra-ocular involvement. We report the removal of a subconjunctival worm and identification by light microscopy (LM) and scanning electron microscopy (SEM).
PURPOSE
: A 62-year-old female presented with complaints of redness, discharge, and foreign body sensation with difficulty in opening eyes in the left eye for the last 3 days. The patient is a non-vegetarian. On examination, her best corrected visual acuity in both eyes was 20/20. On slit lamp examination, there was a long, thin, round, coiled white subconjunctival live worm in the left eye superiorly. The rest of anterior segment evaluation, intra-ocular pressure, and fundus was normal in both eyes. The parasite was removed under local anesthesia from subconjunctival space [Video]. External surface morphology under LM revealed fine transverse cuticular striations with tapered cephalic and caudal ends. Uterus was long and coiled with indistinguishable masses inside. The finding was also confirmed by SEM.
SYNOPSIS
A subconjuctival parasite was removed and identified as Dirofilaria repens by characteristic LM and SEM findings.
HIGHLIGHT
Dirofilaria species may lodge in many tissues of human bodies including eye and adnexa. Dirofilaria is a natural parasite of carnivorous animals, mostly dogs, cats, and foxes. The most common mode of transmission to human is usually by bite of mosquitoes like Culex and Aedes, which are considered as vectors, and it is often thought that parasitemia is because of accidental conduction. Simple surgical removal of the worm is curative. After removal, the worm should be visualized directly under LM. All the internal structures of the transparent worm could be seen and compared with those under SEM.
Topics: Humans; Female; Male; Animals; Dogs; Middle Aged; Microscopy, Electron, Scanning; Parasites; Mosquito Vectors; Eye; Face
PubMed: 37602631
DOI: 10.4103/IJO.IJO_830_23 -
BMC Ecology and Evolution Jun 2022Hosts are often simultaneously infected with several parasite species. These co-infections can lead to within-host interactions of parasites, including mutualism and...
BACKGROUND
Hosts are often simultaneously infected with several parasite species. These co-infections can lead to within-host interactions of parasites, including mutualism and competition, which may affect both virulence and transmission. Birds are frequently co-infected with different haemosporidian parasites, but very little is known about if and how these parasites interact in natural host populations and what consequences there are for the infected hosts. We therefore set out to study Plasmodium and Haemoproteus parasites in house sparrows Passer domesticus with naturally acquired infections using a protocol where the parasitemia (infection intensity) is quantified by qPCR separately for the two parasites. We analysed infection status (presence/absence of the parasite) and parasitemia of parasites in the blood of both adult and juvenile house sparrows repeatedly over the season.
RESULTS
Haemoproteus passeris and Plasmodium relictum were the two dominating parasite species, found in 99% of the analyzed Sanger sequences. All birds were infected with both Plasmodium and Haemoproteus parasites during the study period. Seasonality explained infection status for both parasites in the adults: H. passeris was completely absent in the winter while P. relictum was present all year round. Among adults infected with H. passeris there was a positive effect of P. relictum parasitemia on H. passeris parasitemia and likewise among adults infected with P. relictum there was a positive effect of H. passeris parasitemia on P. relictum parasitemia. No such associations on parasitemia were seen in juvenile house sparrows.
CONCLUSIONS
The reciprocal positive relationships in parasitemia between P. relictum and H. passeris in adult house sparrows suggests either mutualistic interactions between these frequently occurring parasites or that there is variation in immune responses among house sparrow individuals, hence some individuals suppress the parasitemia of both parasites whereas other individuals suppress neither. Our detailed screening of haemosporidian parasites over the season shows that co-infections are very frequent in both juvenile and adult house sparrows, and since co-infections often have stronger negative effects on host fitness than the single infection, it is imperative to use screening systems with the ability to detect multiple parasites in ecological studies of host-parasite interactions.
Topics: Animals; Coinfection; Haemosporida; Humans; Malaria, Avian; Parasitemia; Parasites; Plasmodium; Sparrows
PubMed: 35655150
DOI: 10.1186/s12862-022-02026-5 -
Clinical Microbiology Reviews Jul 2017In the last 2 decades, renewed attention to neglected tropical diseases (NTDs) has spurred the development of antiparasitic agents, especially in light of emerging drug... (Review)
Review
In the last 2 decades, renewed attention to neglected tropical diseases (NTDs) has spurred the development of antiparasitic agents, especially in light of emerging drug resistance. The need for new drugs has required screening methods using parasite culture. Furthermore, clinical laboratories sought to correlate susceptibility methods with treatment outcomes, most notably with malaria. Parasites with their various life cycles present greater complexity than bacteria, for which standardized susceptibility methods exist. This review catalogs the state-of-the-art methodologies used to evaluate the effects of drugs on key human parasites from the point of view of drug discovery as well as the need for laboratory methods that correlate with clinical outcomes.
Topics: Animals; Antiparasitic Agents; Drug Discovery; Humans; Neglected Diseases; Parasites
PubMed: 28446445
DOI: 10.1128/CMR.00111-16 -
PLoS Neglected Tropical Diseases May 2022Insect-vectored Leishmania are responsible for loss of more disability-adjusted life years than any parasite besides malaria. Elucidation of the environmental factors... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Insect-vectored Leishmania are responsible for loss of more disability-adjusted life years than any parasite besides malaria. Elucidation of the environmental factors that affect parasite transmission by vectors is essential to develop sustainable methods of parasite control that do not have off-target effects on beneficial insects or environmental health. Many phytochemicals that inhibit growth of sand fly-vectored Leishmania-which have been exhaustively studied in the search for phytochemical-based drugs-are abundant in nectars, which provide sugar-based meals to infected sand flies.
PRINCIPLE FINDINGS
In a quantitative meta-analysis, we compare inhibitory phytochemical concentrations for Leishmania to concentrations present in floral nectar and pollen. We show that nectar concentrations of several flowering plant species exceed those that inhibit growth of Leishmania cell cultures, suggesting an unexplored, landscape ecology-based approach to reduce Leishmania transmission.
SIGNIFICANCE
If nectar compounds are as effective against parasites in the sand fly gut as predicted from experiments in vitro, strategic planting of antiparasitic phytochemical-rich floral resources or phytochemically enriched baits could reduce Leishmania loads in vectors. Such interventions could provide an environmentally friendly complement to existing means of disease control.
Topics: Animals; Insect Vectors; Leishmania; Parasites; Phlebotomus; Phytochemicals; Plant Nectar; Psychodidae
PubMed: 35551517
DOI: 10.1371/journal.pntd.0010373 -
Biochimica Et Biophysica Acta. General... Jan 2017Resistance against antibiotics is unfortunately still a major biomedical challenge for a wide range of pathogens responsible for potentially fatal diseases. (Review)
Review
BACKGROUND
Resistance against antibiotics is unfortunately still a major biomedical challenge for a wide range of pathogens responsible for potentially fatal diseases.
SCOPE OF REVIEW
In this study, we aim at providing a critical assessment of the recent advances in design and use of drugs targeting genome integrity by perturbation of thymidylate biosynthesis.
MAJOR CONCLUSION
We find that research efforts from several independent laboratories resulted in chemically highly distinct classes of inhibitors of key enzymes within the routes of thymidylate biosynthesis. The present article covers numerous studies describing perturbation of this metabolic pathway in some of the most challenging pathogens like Mycobacterium tuberculosis, Plasmodium falciparum, and Staphylococcus aureus.
GENERAL SIGNIFICANCE
Our comparative analysis allows a thorough summary of the current approaches to target thymidylate biosynthesis enzymes and also include an outlook suggesting novel ways of inhibitory strategies. This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo.
Topics: Animals; Bacteria; Enzyme Inhibitors; Genomic Instability; Parasites; Viruses
PubMed: 27217086
DOI: 10.1016/j.bbagen.2016.05.024 -
PLoS Pathogens Nov 2023Signalling pathways in malaria parasite remain poorly defined and major reason for this is the lack of understanding of the function of majority of parasite protein...
Signalling pathways in malaria parasite remain poorly defined and major reason for this is the lack of understanding of the function of majority of parasite protein kinases and phosphatases in parasite signalling and its biology. In the present study, we have elucidated the function of Protein Kinase 2 (PfPK2), which is known to be indispensable for the survival of human malaria parasite Plasmodium falciparum. We demonstrate that it is involved in the invasion of host erythrocytes, which is critical for establishing infection. In addition, PfPK2 may also be involved in the maturation of the parasite post-invasion. PfPK2 regulates the release of microneme proteins like Apical Membrane Antigen 1 (AMA1), which facilitates the formation of Tight Junction between the merozoite and host erythrocyte- a key step in the process of invasion. Comparative phosphoproteomics studies revealed that PfPK2 may be involved in regulation of several key proteins involved in invasion and signalling. Furthermore, PfPK2 regulates the generation of cGMP and the release of calcium in the parasite, which are key second messengers for the process of invasion. These and other studies have shed light on a novel signalling pathway in which PfPK2 acts as an upstream regulator of important cGMP-calcium signalling, which plays an important role in parasite invasion.
Topics: Animals; Humans; Protein Kinases; Protozoan Proteins; Parasites; Calcium; Plasmodium falciparum; Erythrocytes
PubMed: 37988347
DOI: 10.1371/journal.ppat.1011770