Search Results (833)

Leeches (Hirudinea) are ecologically important annelids that interact with a wide range of aquatic vertebrates, yet their diversity, distribution, and epidemiological relevance remain poorly documented in North Africa. Here, we provide a comprehensive synthesis of freshwater and marine leech species reported from the Maghreb (Algeria, Tunisia, and Morocco), based on an extensive review of the available literature. In total, 21 species belonging to 13 genera and four families (Glossiphoniidae, Erpobdellidae, Hirudinidae, and Piscicolidae) are documented, with updated information on their ecology, host associations, and geographic distribution. In addition to this regional checklist, we report the first confirmed case of Batracobdella algira heavy parasitism on the Berber toad (Sclerophrys mauritanica) in Algeria. A single adult toad was found heavily infested by multiple leeches (n = 17), some of which bore spermatophores attached near the reproductive opercula, suggesting possible in situ mating behavior on the host. The high infestation observed in this single specimen may constitute an outlier, requiring further sampling to assess the effect of leeches on the anuran population in the region. By integrating faunistic data with a novel field observation, this study highlights the overlooked leech biodiversity in the Maghreb and suggests their possible ecological and epidemiological significance. Our findings emphasize the need for further investigations into leech–host interactions, pathogen carriage, and their implications for amphibian conservation and One Health in North Africa. Full article

Toxoplasma gondii, the causative agent of toxoplasmosis, a disease widely distributed, is an intracellular parasite that invades host cells of different tissues using specialized endocytic activity. Recent studies suggest that tunneling nanotubes (TNTs), thin cell-surface projections, may participate in the parasite–host cell interaction. Here we report results that suggest the involvement of host-cell TNTs in the adhesion of T. gondii tachyzoites to epithelial LLC-MK² cells. Microscopy analysis showed that incubating cells in a medium containing 0.45 M sucrose induces reversible assembly of TNTs without affecting cell viability. The presence of extended TNTs correlated with increased parasite adhesion and reduced parasite entry, thus suggesting a structural or signaling role in mediating adhesion. TNTs assembled following sucrose incubation contain both actin and tubulin components as determined by immunofluorescence microscopy. These results highlight a possible functional relevance of TNTs in T. gondii host cell interaction, especially in parasite adhesion, opening new perspectives for understanding T. gondii-host cell interaction. Full article

Huanglongbing (HLB) is the most serious disease affecting citrus production worldwide, and its management relies on controlling its vector, Diaphorina citri. Although Tamarixia radiata (Waterston) is widely used in biological control programmes, Diaphorencyrtus aligarhensis (Shafee et al.) has been proposed as a complementary agent; both species were reported in Colombia in 2016, yet their interaction dynamics under local conditions remain poorly understood. This study evaluated the development, morphometry, and interaction patterns of both parasitoids under controlled rearing conditions using a shared host population. Three treatments were established: non-parasitised nymphs, nymphs exposed to D. aligarhensis, and nymphs exposed to T. radiata, with parasitoids allowed to oviposit for 24 h. Developmental duration and morphometric traits were recorded daily. T. radiata completed its life cycle in less time (~11.7 days) than D. aligarhensis (~14.4 days) and than non-parasitized nymphs (~17 days). Morphometric traits were consistent with previously reported ranges, and this study provides the first detailed characterisation of the immature stages of D. aligarhensis in Colombia. Particularly, events of multiparasitoidism and superparasitoidism were documented under standardised conditions, demonstrating that both species can exploit the same host simultaneously. These findings offer new insights into parasitoid interaction dynamics and establish a biological foundation for developing integrated biological control strategies against D. citri. Full article

Cholangiocarcinoma (CCA) is an aggressive malignancy with a poor prognosis that is strongly associated with chronic Clonorchis sinensis (C. sinensis, Cs) infection; however, its underlying molecular mechanisms remain elusive. Recent studies suggest that C. sinensis-derived extracellular vesicles (CsEVs) play a crucial role in host–parasite interactions and in shaping the tumor microenvironment during infection. Acting as key delivery vehicles, these CsEVs can transfer specific functional molecules, such as microRNAs (miRNAs), to host cholangiocytes, thereby modulating cellular behaviors—a process that may represent a significant pathway in parasite-induced carcinogenesis. Despite this, the specific miRNAs shuttled by CsEVs and their concrete functions and mechanisms in driving CCA proliferation and metastasis remain largely unexplored. To this end, we investigated Csi-miR-125a, a miRNA abundantly expressed in CsEVs, aiming to systematically elucidate its dual regulatory functions in CCA progression. Our findings offer novel mechanistic insights into host–parasite crosstalk, further the understanding of CCA pathogenesis, and point to potential therapeutic avenues. Using gain-and loss-of-function approaches in RBE and HuCCT1 cell lines, we demonstrated that Csi-miR-125a promotes cell proliferation by accelerating cell-cycle progression and suppressing apoptosis through direct targeting of BAK1. Concurrently, Csi-miR-125a enhances the migratory and invasive capacities of CCA cells via activation of the ERK signaling pathway. In a BALB/c nude mouse lung metastasis model, CsEVs depleted of Csi-miR-125a significantly inhibited pulmonary metastasis. Collectively, This study found that Csi-miR-125a derived from C. sinensis can regulate apoptosis and cell cycle progression by targeting BAK1, thereby promoting the proliferation of cholangiocarcinoma cells; meanwhile, it enhances cell migration and invasion by activating the ERK signaling pathway. These results suggest that Csi-miR-125a participates in and promotes the malignant progression of CCA. However, given its high homology with human endogenous miR-125a, its function may partially overlap with host endogenous miRNAs, rather than representing a completely independent carcinogenic effect. These findings provide mechanistic insights into host–parasite interactions during C. sinensis infection and lay a theoretical foundation for subsequent targeted intervention studies. Full article

The present study investigated the effect of Ligula intestinalis L. infection on several components of the antioxidant system and on protein oxidation in the host fish, common bream Abramis brama L. In ligulosed bream, the hepatopancreatic antioxidant system response included a decrease in catalase (CAT) activity, an increase in glutathione S-transferase (GST) activity, and no change in superoxide dismutase (SOD) activity. The contents of molecular antioxidants in the organs of infected bream were inconsistent; for instance, hepatopancreatic α-tocopherol content was significantly lower, whereas retinol content was significantly higher than in uninfected individuals. In contrast, no significant differences were found in the α-tocopherol or retinol content in the skeletal muscles of infected and uninfected fish. The protein oxidation, estimated via protein carbonyl content, was unaffected by ligulosis, as was the activity of proteasomes. However, the activity of calpain, another protease, was significantly higher in the skeletal muscle of infected fish. Overall, the data reveal moderate and tissue-specific alterations in oxidative stress markers in A. brama infected with L. intestinalis, suggesting a complex host–parasite interaction that does not result in severe systemic oxidative damage under the studied conditions. Full article

Climate change significantly impacts agricultural ecosystems through rising temperatures, changing precipitation patterns, increasing atmospheric CO₂ levels, and more frequent extreme weather events. These environmental changes have a pronounced effect on plant-parasitic nematodes (PPNs; phylum Nematoda), which cause serious crop losses on a global scale. This review aims to provide a comprehensive evaluation of current knowledge on how major climate change drivers influence the biology, population dynamics, host–plant interactions, and geographic distribution of PPNs in agricultural systems. Recent studies show that rising temperatures accelerate nematode development, increasing the number of generations within a production season and facilitating the spread of many economically important species toward higher latitudes and elevations. Changes in precipitation patterns and soil moisture directly affect nematode survival, mobility, and infection success, and these effects often vary depending on regional conditions and nematode species. Elevated atmospheric CO₂ levels modify plant–nematode interactions by increasing root biomass, altering rhizosphere processes, and regulating plant defense pathways (e.g., jasmonic acid and salicylic acid signaling), which may enhance host susceptibility and infection intensity. Furthermore, extreme climate events can disrupt the natural balance in soil ecosystems, weakening natural antagonist–nematode relationships. However, responses of PPNs to climate change are not uniform, and contrasting findings across studies indicate that these responses are strongly shaped by species-specific traits and environmental variability. In addition, future research should focus on long-term and multi-factorial field studies to better capture the combined effects of climate drivers. Overall, climate change is expected to increase PPN prevalence and drive shifts in their geographic distribution, highlighting the need for climate-sensitive and regionally adapted nematode management strategies. Full article

Parasites are integral components of marine ecosystems, providing insights into host biology, trophic interactions, and environmental variability. This study presents the first systematic characterization of the metazoan parasite community of the Green Jack (Caranx caballus) in the northern Colombian Pacific, a region designated as an Exclusive Artisanal Fishing Zone (ZEPA) but with limited parasitological research. Specimens were collected from the Cupica Gulf across wet and dry seasons, and parasitological analyses were conducted to evaluate parasite load, community structure, spatial distribution, and seasonal variation. Of 46 fish examined, 20 were parasitized (overall prevalence: 43.5%), with low infection intensities (1–3 parasites per fish). Nine parasite species were identified, including monogeneans, digeneans, and copepods. Copepods (Caligus sp.) represented the most species-rich and dominant group, while Allopyragraphorus caballeroi exhibited aggregated distribution. Parasite communities showed low richness and diversity, seasonal stability, and strong trophic linkages to crustacean prey, particularly brachyuran megalopa. Host condition was unaffected by parasitism, suggesting resilience under current infection levels. These findings provide the first reference on parasite richness and diversity for C. caballus in Colombia, extending the known distribution of several species within the Eastern Tropical Pacific and underscoring the role of parasites as biological markers for fisheries monitoring and ecosystem change. Full article

The montane water vole, Arvicola scherman, is a fossorial rodent that lives underground in grasslands, pastures and meadows in the mountain ranges of southwestern and central Europe. It feeds mainly on grasses, roots, and bulbs, causing considerable economic damage to agriculture. Consequently, it is recognised as one of the most important pest vole species in European agroecosystems. The dynamics of these pest populations may be affected by interactions with their parasites. For this reason, an helminthoecological study was carried out in Asturias (NW Spain), analysing a total of 815 montane water voles, 464 (56.9%) of which were parasitised by at least one of the six helminth species detected: Hydatigera taeniaeformis s.l. larvae (9%), Aonchotheca wioletti (0.1%), Eucoleus bacillatus (0.4%), Trichuris arvicolae (7%), Carolinensis minutus (30%) and Syphacia nigeriana (12%). The helminth community found was compared with that reported from A. scherman analysed in other locations of the Iberian Peninsula. This study also analyses the influence of intrinsic and extrinsic factors on the prevalence and abundance of the helminth component species, with host age and body condition being the most influential determinants. H. taeniaeformis s.l. and T. arvicolae are postulated as potential regulators of the analysed population, a pest in crops from NW Spain. Full article

Horizontal Gene Transfer (HGT) is a hallmark of the evolution of parasitic plants, facilitated by the haustorial connection. While mitochondrial HGT is widespread, the extent of nuclear HGT and the long-term retention of foreign genetic material in holoparasitic lineages remain poorly understood. This study explores the genomic architecture of Prosopanche americana (Hydnoraceae), a non-photosynthetic holoparasite currently specialized on Fabaceae. Through a comparative phylogenomic approach integrating draft mitochondrial genomes (mtDNA) and nuclear transcriptomes of P. americana, we identified a multi-layered landscape of foreign DNA. The mtDNA of P. americana contains 18 foreign regions (>500 bp) primarily derived from Solanales, Malvales, and Fabales. Notably, 13 of these regions are shared with P. panguanensis, indicating they were acquired in their common ancestor before speciation and ecological shift. In the nuclear genome, we identified 303 horizontally acquired transcripts (99 orthogroups) with high confidence. Functional analysis revealed an enrichment of foreign genes involved in metabolic pathways and plastid functions (e.g., photosystems and thylakoids) exclusively derived from the ancestral host order Solanales. Our results demonstrate that the genome of P. americana acts as a “molecular fossil,” preserving evidence of past ecological interactions with diverse host lineages. The disparity in HGT footprints between the current host (Fabaceae) and ancestral hosts suggests a period of high genomic plasticity followed by host specialization, providing new insights into the timing and dynamics of horizontal gene flow in holoparasitic Piperales. Full article

Background: While Toxoplasma gondii infection poses a significant health threat, its impact on the localized intestinal lipid metabolism remains unclear. Methods: Thus, this study established an acute infection model in BALB/cJ mice and analyzed the colonic contents collected 10 days post-infection via untargeted lipidomics. The lipid profiles of the two groups diverged substantially, with a clear separation evident between infection and control conditions. Results: We identified 65 upregulated and 87 downregulated differential lipids, primarily falling into the glycerophospholipids and sphingolipids categories. Pathway enrichment analysis revealed that the choline metabolism in cancer and glycerophospholipid metabolism pathways was pinpointed as being among the most perturbed following infection. Correlation and network analyses further suggested that key molecules, such as LPC (20:4) and LPA (18:0), may mediate these metabolic pathway abnormalities by regulating related enzymatic activities. Conclusions: This systematic characterization of the intestinal lipid metabolic landscape in mice during acute T. gondii infection revealed the host intestinal lipid metabolic reprogramming induced by T. gondii infection. The findings offer a novel metabolic perspective for understanding T. gondii pathogenesis and host–parasite interactions. Full article

Malaria, caused by Plasmodium parasites, remains a global health crisis, necessitating novel therapeutic strategies targeting host–parasite interactions. During liver-stage infection, parasites exploit host vesicular trafficking machinery, particularly SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins that mediate membrane fusion. Using a CRISPR/Cas9 knockout system in HeLa cells combined with advanced microscopy of Plasmodium berghei-infected HeLa cells, we identified specific endolysosomal SNAREs including Vesicle-Associated Membrane Protein 7 (VAMP7), Vesicle-Associated Membrane Protein 8 (VAMP8), Vesicle Transport Through Interaction With T-SNAREs 1B (Vti1B), and Syntaxin 7 (Stx7) to be recruited to the parasitophorous vacuole membrane (PVM) with distinct temporal profiles. This demonstrates the parasite’s precise manipulation of host endolysosomal trafficking pathways. VAMP7 and Vti1B were localized to the PVM within 30 min post-infection, suggesting potential roles during invasion, while VAMP8 and Stx7 appeared later around 24 h post infection (hpi), coinciding with increased nutrient acquisition. Single gene deletions showed minimal impact, but combinatorial knockouts (KO) revealed critical redundancy. VAMP7-VAMP8 as well as VAMP7–Vti1B double KO significantly reduced parasite infection and growth, with Vti1B playing a dominant role. Triple KO phenotypes mirrored VAMP7-Vti1B disruption, underscoring Vti1B’s dominant role. SNARE depletion also impaired the lysosome–PVM association and LAMP1 positive vesicle recruitment. Our findings indicate Plasmodium hijacks a coordinated host SNARE network to fuse lysosomes with the PVM for nutrient uptake. Targeting Vti1B-containing complexes disrupts this pathway without host cell toxicity, offering a promising host-directed antimalarial approach. Full article

The apple rust fungus Gymnosporangium yamadae (G. yamadae) secretes effector proteins into host apple leaf cells to facilitate parasitism. Among these, the candidate effector GyHRb12 was found to localize to the nucleus upon transient expression in Nicotiana benthamiana leaf cells, although its functional role remained unclear. Subsequent investigations demonstrated that overexpression of GyHRb12 protein decreases plant cell resistance and attenuates the transcription of multiple antifungal-related genes. Using a yeast two-hybrid screen, MdRPS20, a component of the 30S ribosomal subunit, was identified as an interactor of GyHRb12. Proteomic analysis revealed that GyHRb12 modulates the expression of proteins involved in protein translation processes, which may be mediated by changes in ribosomal abundance. Notably, mutating the 14th amino acid in MdRPS20 disrupted its interaction with GyHRb12, underscoring the critical role of this residue in effector recognition and subsequent suppression of host immunity. Collectively, these findings demonstrate that G. yamadae employs a nuclear-localized effector to target a ribosomal subunit protein, thereby reprogramming host translation activity and suppressing host immunity. Full article

Scavenger Receptors (SRs) comprise a structurally diverse group of pattern recognition receptors (PRRs) involved in sensing non-self (microbial-associated molecular patterns) or altered-self ligands. CD5 and CD6 are class I SRs (SR-I) preferentially expressed by lymphoid cells and characterized by the presence of several tandem scavenger receptor cysteine-rich (SRCR) domain repeats. Both receptors interact with diverse microbial structures, including tegumental antigens from Echinococcus granulosus sensu lato (s.l.), the cestode parasite responsible for cystic echinococcosis (CE). This is notable as very few PRRs are currently known to detect parasitic helminths and because the infusion of recombinant soluble CD5 and CD6 proteins has shown prophylactic effects in murine secondary CE. Herein, the role of CD5 and CD6 in early immune responses to E. granulosus s.l. tegumental antigens (PSEx) was analyzed using CD5 (Cd5^−/−) and CD6 (Cd6^−/−)-deficient mice. Peritoneal B cells and macrophages from wild-type mice displayed specific and dose-dependent PSEx binding, which was impaired in those from Cd5^−/− and Cd6^−/− mice, supporting direct and/or indirect roles in parasite recognition. Additionally, in vivo exposure of peritoneal exudate cells (PECs) from Cd5^−/− and Cd6^−/− mice to PSEx showed altered activation profiles, including changes in CD80/CD86 expression, impaired early production of natural polyreactive antibodies, and cytokine shift from a Th1/Th17 to a Th2 profile. These findings strongly support the involvement of CD5 and CD6 receptors in the early immune recognition of E. granulosus s.l. antigens by PECs and influence immune responses critical for host resistance, highlighting their relevance in host–parasite interactions. Full article

Neuropeptides regulate diverse physiological and behavioural processes in parasites, yet their functional roles in the infective larval stages of Schistosoma mansoni remain poorly defined. In this study, we identified miracidia-derived putative neuropeptides and examined their roles in regulating miracidial behaviour. Peptidomic analysis revealed ten putative neuropeptides, including five whose proteomic identification in this life stage was previously unreported. Neuropeptide precursor proteins were evaluated for stage-specific expression and Schistosoma genus specificity to prioritise candidates with potential functional and biocontrol relevance. Protein–protein interaction analysis identified Smp_176700 as a highly connected neuropeptide precursor associated with proteins implicated in miracidial structure and infection. Eight putative neuropeptides derived from six precursor proteins were synthesised and externally applied to miracidia in acute (1 min) and prolonged (360 min) behavioural assays. During acute exposure, most peptides induced significant concentration-dependent behavioural changes at 3 mg/mL and 0.1 mg/mL, characterised by reduced swimming velocity and increased directional change, with no significant effects at 0.01 mg/mL. Prolonged exposure revealed peptide-specific effects, with ASLSYF-OH and FLLGLPPSLRQH-OH producing the most pronounced behavioural modulation. These findings demonstrate that S. mansoni miracidia express bioactive neuropeptides capable of modulating larval behaviour, providing insight into schistosome neurobiology and identifying potential targets for transmission-blocking interventions. Full article

Parasitism plays an important role in many fundamental ecological processes and is widespread both geographically and taxonomically. Interactions between parasites and hosts are often complex, and much attention has been paid to the relationship between host traits and parasitism. However, a comprehensive review of the association between host personality and parasitic infection is lacking. In this review, we systematically synthesized 54 studies published over the past few decades. Generally, the relationship between animal personality traits and parasitic infection is complex, and no generic pattern exists. Many biological processes may be involved, and biological factors (such as host sex and parasite type) may significantly shape the personality–infection relationship. Different personality traits may also indicate different relationships with parasitic infection. We confirmed that host personality and parasitic infection exhibit a mutually influential, multi-feedback dynamic. Finally, several research gaps were described, and we emphasized the importance of incorporating the BACI design in experiments. Full article