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Parasitology Research Apr 2024Co-exposure to multiple parasites can alter parasite success and host life history when compared to single infections. These infection outcomes can be affected by the...
Co-exposure to multiple parasites can alter parasite success and host life history when compared to single infections. These infection outcomes can be affected by the order of parasite arrival, the host immune response, and the interspecific interactions among co-infecting parasites. In this study, we examined how the arrival order of two trematode parasites, Schistosoma mansoni and Echinostoma caproni, influenced parasite ecology and the life history of their snail host, Biomphalaria glabrata. Snail hosts were exposed to E. caproni cercariae before, with, and after their exposure to S. mansoni miracidia. We then measured the effects of this timing on infection prevalence, infection intensity of E. caproni metacercariae, and cercarial output of S. mansoni, as well as on snail reproduction and survival. Snails infected only with S. mansoni and snails exposed to E. caproni after S. mansoni both shed more cercariae than simultaneously exposed snails. Additionally, S. mansoni prevalence was lower in snails that were first exposed to E. caproni compared to snails that were exposed to E. caproni after S. mansoni. Moreover, snails exposed to E. caproni before S. mansoni did not differ in their survival compared to control snails, whereas simultaneously exposed snails and snails exposed to E. caproni after S. mansoni had lower survival than control snails. Combined, this prevalence and survival data suggest a potential protective role of early E. caproni exposure. The timing of E. caproni exposure impacts S. mansoni establishment and reproduction, but host survival patterns are likely driven by S. mansoni prevalence alone.
Topics: Animals; Parasites; Biomphalaria; Cercaria; Echinostoma; Ecology
PubMed: 38634931
DOI: 10.1007/s00436-024-08205-1 -
PLoS Computational Biology Mar 2024Plasmodium vivax is one of the most geographically widespread malaria parasites in the world, primarily found across South-East Asia, Latin America, and parts of Africa.... (Review)
Review
Plasmodium vivax is one of the most geographically widespread malaria parasites in the world, primarily found across South-East Asia, Latin America, and parts of Africa. One of the significant characteristics of the P. vivax parasite is its ability to remain dormant in the human liver as hypnozoites and subsequently reactivate after the initial infection (i.e. relapse infections). Mathematical modelling approaches have been widely applied to understand P. vivax dynamics and predict the impact of intervention outcomes. Models that capture P. vivax dynamics differ from those that capture P. falciparum dynamics, as they must account for relapses caused by the activation of hypnozoites. In this article, we provide a scoping review of mathematical models that capture P. vivax transmission dynamics published between January 1988 and May 2023. The primary objective of this work is to provide a comprehensive summary of the mathematical models and techniques used to model P. vivax dynamics. In doing so, we aim to assist researchers working on mathematical epidemiology, disease transmission, and other aspects of P. vivax malaria by highlighting best practices in currently published models and highlighting where further model development is required. We categorise P. vivax models according to whether a deterministic or agent-based approach was used. We provide an overview of the different strategies used to incorporate the parasite's biology, use of multiple scales (within-host and population-level), superinfection, immunity, and treatment interventions. In most of the published literature, the rationale for different modelling approaches was driven by the research question at hand. Some models focus on the parasites' complicated biology, while others incorporate simplified assumptions to avoid model complexity. Overall, the existing literature on mathematical models for P. vivax encompasses various aspects of the parasite's dynamics. We recommend that future research should focus on refining how key aspects of P. vivax dynamics are modelled, including spatial heterogeneity in exposure risk and heterogeneity in susceptibility to infection, the accumulation of hypnozoite variation, the interaction between P. falciparum and P. vivax, acquisition of immunity, and recovery under superinfection.
Topics: Animals; Humans; Plasmodium vivax; Superinfection; Malaria, Vivax; Malaria; Models, Theoretical; Malaria, Falciparum; Parasites; Recurrence
PubMed: 38483975
DOI: 10.1371/journal.pcbi.1011931 -
Virulence Dec 2024Bacterial biofilms have attracted significant attention due to their involvement in persistent infections, food and water contamination, and infrastructure corrosion.... (Review)
Review
Bacterial biofilms have attracted significant attention due to their involvement in persistent infections, food and water contamination, and infrastructure corrosion. This review delves into the intricate interactions between bacterial biofilms and unicellular parasites, shedding light on their impact on biofilm formation, structure, and function. Unicellular parasites, including protozoa, influence bacterial biofilms through grazing activities, leading to adaptive changes in bacterial communities. Moreover, parasites like and can shape biofilm composition in a grazing independent manner, potentially influencing disease outcomes. Biofilms, acting as reservoirs, enable the survival of protozoan parasites against environmental stressors and antimicrobial agents. Furthermore, these biofilms may influence parasite virulence and stress responses, posing challenges in disease treatment. Interactions between unicellular parasites and fungal-containing biofilms is also discussed, hinting at complex microbial relationships in various ecosystems. Understanding these interactions offers insights into disease mechanisms and antibiotic resistance dissemination, paving the way for innovative therapeutic strategies and ecosystem-level implications.
Topics: Animals; Parasites; Ecosystem; Biofilms; Drug Resistance, Microbial; Anti-Infective Agents; Bacteria
PubMed: 38058008
DOI: 10.1080/21505594.2023.2289775 -
Ecology Letters Jan 2024Despite the importance of virulence in epidemiological theory, the relative contributions of host and parasite to virulence outcomes remain poorly understood. Here, we...
Despite the importance of virulence in epidemiological theory, the relative contributions of host and parasite to virulence outcomes remain poorly understood. Here, we use reciprocal cross experiments to disentangle the influence of host and parasite on core virulence components-infection and pathology-and understand dramatic differences in parasite-induced malformations in California amphibians. Surveys across 319 populations revealed that amphibians' malformation risk was 2.7× greater in low-elevation ponds, even while controlling for trematode infection load. Factorial experiments revealed that parasites from low-elevation sites induced higher per-parasite pathology (reduced host survival and growth), whereas there were no effects of host source on resistance or tolerance. Parasite populations also exhibited marked differences in within-host distribution: ~90% of low-elevation cysts aggregated around the hind limbs, relative to <60% from high-elevation. This offers a novel, mechanistic basis for regional variation in parasite-induced malformations while promoting a framework for partitioning host and parasite contributions to virulence.
Topics: Animals; Parasites; Trematoda; Virulence; Host-Parasite Interactions; Trematode Infections; Amphibians
PubMed: 38115188
DOI: 10.1111/ele.14352 -
Parasitology Sep 2023Combining the biogeography and phylogenetic patterns of parasite-host associations allows a better understanding of the history of parasite–host interactions, which...
Combining the biogeography and phylogenetic patterns of parasite-host associations allows a better understanding of the history of parasite–host interactions, which can be achieved biogeographic regionalization incorporating phylogenetic information. Recently, the concepts of evoregions (regions where a majority of species evolved from one or several ancestors inhabiting these regions) and evolutionary transition zones (regions of high phylogenetic turnover) have been proposed, coupled with a classification approach for these concepts. We applied this approach to 206 flea species and 265 host species of the Palearctic and aimed to identify evoregions and evolutionary transition zones for both fleas and hosts and to understand whether these evoregions and transition zones match each other. We identified 5 evoregions with 3 transition zones for either fleas or hosts, but neither the positions and boundaries of the flea and host evoregions nor the transition zones coincided. Indications of multiple geographic centres of diversification of the same flea lineages suggested that (a) the common evolutionary history of fleas and hosts was characterized by multiple events other than codiversification and that (b) dispersal played an important role in flea and host assemblies. Barriers to dispersal could be represented by landscape features (deserts and mountain ranges) and/or climate differences.
Topics: Animals; Siphonaptera; Phylogeny; Flea Infestations; Mammals; Parasites; Host-Parasite Interactions
PubMed: 37705252
DOI: 10.1017/S0031182023000884 -
Frontiers in Cellular and Infection... 2023is an Apicomplexa responsible for human malaria, a major disease causing more than ½ million deaths every year, against which there is no fully efficient vaccine. The...
is an Apicomplexa responsible for human malaria, a major disease causing more than ½ million deaths every year, against which there is no fully efficient vaccine. The current rapid emergence of drug resistances emphasizes the need to identify novel drug targets. Increasing evidences show that lipid synthesis and trafficking are essential for parasite survival and pathogenesis, and that these pathways represent potential points of attack. Large amounts of phospholipids are needed for the generation of membrane compartments for newly divided parasites in the host cell. Parasite membrane homeostasis is achieved by an essential combination of parasite lipid synthesis/recycling and massive host lipid scavenging. Latest data suggest that the mobilization and channeling of lipid resources is key for asexual parasite survival within the host red blood cell, but the molecular actors allowing lipid acquisition are poorly characterized. Enzymes remodeling lipids such as phospholipases are likely involved in these mechanisms. possesses an unusually large set of phospholipases, whose functions are largely unknown. Here we focused on the putative patatin-like phospholipase PNPLA2, for which we generated an glmS-inducible knockdown line and investigated its role during blood stages malaria. Disruption of the mitochondrial PNPLA2 in the asexual blood stages affected mitochondrial morphology and further induced a significant defect in parasite replication and survival, in particular under low host lipid availability. Lipidomic analyses revealed that PNPLA2 specifically degrades the parasite membrane lipid phosphatidylglycerol to generate lysobisphosphatidic acid. PNPLA2 knockdown further resulted in an increased host lipid scavenging accumulating in the form of storage lipids and free fatty acids. These results suggest that PNPLA2 is involved in the recycling of parasite phosphatidylglycerol to sustain optimal intraerythrocytic development when the host resources are scarce. This work strengthens our understanding of the complex lipid homeostasis pathways to acquire lipids and allow asexual parasite survival.
Topics: Animals; Humans; Plasmodium falciparum; Phospholipases; Mitophagy; Phosphatidylglycerols; Protozoan Proteins; Malaria, Falciparum; Parasites; Erythrocytes; Malaria
PubMed: 38089812
DOI: 10.3389/fcimb.2023.997245 -
The New England Journal of Medicine Aug 2023Partial resistance of to the artemisinin component of artemisinin-based combination therapies, the most important malaria drugs, emerged in Southeast Asia and now...
BACKGROUND
Partial resistance of to the artemisinin component of artemisinin-based combination therapies, the most important malaria drugs, emerged in Southeast Asia and now threatens East Africa. Partial resistance, which manifests as delayed clearance after therapy, is mediated principally by mutations in the kelch protein K13 (PfK13). Limited longitudinal data are available on the emergence and spread of artemisinin resistance in Africa.
METHODS
We performed annual surveillance among patients who presented with uncomplicated malaria at 10 to 16 sites across Uganda from 2016 through 2022. We sequenced the gene encoding kelch 13 () and analyzed relatedness using molecular methods. We assessed malaria metrics longitudinally in eight Ugandan districts from 2014 through 2021.
RESULTS
By 2021-2022, the prevalence of parasites with validated or candidate resistance markers reached more than 20% in 11 of the 16 districts where surveillance was conducted. The PfK13 469Y and 675V mutations were seen in far northern Uganda in 2016-2017 and increased and spread thereafter, reaching a combined prevalence of 10 to 54% across much of northern Uganda, with spread to other regions. The 469F mutation reached a prevalence of 38 to 40% in one district in southwestern Uganda in 2021-2022. The 561H mutation, previously described in Rwanda, was first seen in southwestern Uganda in 2021, reaching a prevalence of 23% by 2022. The 441L mutation reached a prevalence of 12 to 23% in three districts in western Uganda in 2022. Genetic analysis indicated local emergence of mutant parasites independent of those in Southeast Asia. The emergence of resistance was observed predominantly in areas where effective malaria control had been discontinued or transmission was unstable.
CONCLUSIONS
Data from Uganda showed the emergence of partial resistance to artemisinins in multiple geographic locations, with increasing prevalence and regional spread over time. (Funded by the National Institutes of Health.).
Topics: Animals; Humans; Artemisinins; Benchmarking; Parasites; Uganda; Drug Resistance; Malaria; Protozoan Proteins
PubMed: 37611122
DOI: 10.1056/NEJMoa2211803 -
Frontiers in Cellular and Infection... 2023
Topics: Animals; Parasites; Multiomics; Proteomics
PubMed: 37780851
DOI: 10.3389/fcimb.2023.1281638 -
Parasites & Vectors Jul 2023A close connection between a protozoan parasite and the balance of the other gut microbes of the host has been demonstrated. The calves may be naturally co-infected with...
BACKGROUND
A close connection between a protozoan parasite and the balance of the other gut microbes of the host has been demonstrated. The calves may be naturally co-infected with many parasites, and the co-effects of parasites on other intestinal microbes of calves remain unclear. This study aims to preliminarily reveal the relationship between intestinal parasites and other intestinal microbes in calves.
METHODS
Fecal samples were collected from four calves with bloody diarrhea, four calves with watery diarrhea, and seven normal calves, and the microbial flora of the samples were analyzed by whole-genome sequencing. Protozoal parasites were detected in the metagenome sequences and identified using polymerase chain reaction (PCR).
RESULTS
Cryptosporidium, Eimeria, Giardia, Blastocystis, and Entamoeba were detected by metagenomic analysis, and the identified species were Giardia duodenalis assemblage E, Cryptosporidium bovis, Cryptosporidium ryanae, Eimeria bovis, Eimeria subspherica, Entamoeba bovis, and Blastocystis ST2 and ST10. Metagenomic analysis showed that the intestinal microbes of calves with diarrhea were disordered, especially in calves with bloody diarrhea. Furthermore, different parasites show distinct relationships with the intestinal microecology. Cryptosporidium, Eimeria, and Giardia were negatively correlated with various intestinal bacteria but positively correlated with some fungi. However, Blastocystis and Entamoeba were positively associated with other gut microbes. Twenty-seven biomarkers not only were significantly enriched in bloody diarrhea, watery diarrhea, and normal calves but were also associated with Eimeria, Cryptosporidium, and Giardia. Only Eimeria showed a distinct relationship with seven genera of bacteria, which were significantly enriched in the healthy calves. All 18 genera of fungi were positively correlated with Cryptosporidium, Eimeria, and Giardia, which were also significantly enriched in calves with bloody diarrhea. Functional genes related to parasites and diseases were found mainly in fungi.
CONCLUSIONS
This study revealed the relationship between intestinal protozoan parasites and the other calf gut microbiome. Different intestinal protozoan parasites have diametrically opposite effects on other gut microecology, which not only affects bacteria in the gut, but also is significantly related to fungi and archaea.
Topics: Animals; Cattle; Parasites; Cryptosporidiosis; Cryptosporidium; Metagenome; Intestinal Diseases, Parasitic; Giardiasis; Giardia; Giardia lamblia; Blastocystis; Eimeria; Entamoeba; Feces; Diarrhea
PubMed: 37525231
DOI: 10.1186/s13071-023-05877-z -
Parasites & Vectors Feb 2024ParSCo (Parasitology Summer Course) is an intense, 1-week-long summer course organized by the Parasitology Unit of the Department of Veterinary Medicine, University of...
ParSCo (Parasitology Summer Course) is an intense, 1-week-long summer course organized by the Parasitology Unit of the Department of Veterinary Medicine, University of Bari, Italy, with the support of the World Association for the Advancement of Veterinary Parasitology (WAAVP), the European Veterinary Parasitology College (EVPC) and Parasites and Vectors. The course, which is conducted in southern Italy, is planned for parasitologists and post-graduate students working in the field of parasitology. The course consists of theoretical and practical lessons, which include the collection, identification and diagnosis of parasites of pets, livestock and wildlife. The participants in ParSCo are afforded the opportunity to be involved in clinical examination and sample collection for the diagnosis of parasitic diseases (e.g. leishmaniosis, thelaziosis and many tick-borne diseases) present in the Mediterranean Basin. The course is conducted at Casa di Caccia, a hunting lodge situated in the Gallipoli Cognato Forest near the Basento River in the Basilicata region in southern Italy. In addition to the training purpose, ParSCo is a great opportunity for sharing knowledge and expertise while becoming part of the parasitology community in a pleasant environment. In this editorial, we share some information and celebrate 10 years of ParSCo, looking forward to forthcoming sessions of this unique parasitology summer course.
Topics: Animals; Humans; Parasitic Diseases, Animal; Students; Livestock; Animals, Wild; Italy; Parasitology
PubMed: 38409043
DOI: 10.1186/s13071-024-06174-z