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Ecological and methodological insights from genetic and coprological profiling of gastrointestinal communities in wild howler monkeys.

The gastrointestinal tract hosts a complex community of microorganisms and helminth parasites that collectively contribute to host health and fitness. Analysis of these communities provides insight into diverse aspects of host dietary ecology, immunity, nutrition, and host-parasite interactions. However, research methodologies, such as sample preservation and sequencing approach, can influence how we understand and characterize these features. Here, we profiled the gastrointestinal microbial and helminth communities in different groups of wild Costa Rican mantled howler monkeys (Alouatta palliata palliata). We compared samples stored in ethanol versus directly flash frozen, and contrasted conclusions drawn from 16S versus shotgun sequencing approaches. Bacterial, archaeal, and eukaryotic taxa associated with the digestion of plant material dominated the GI communities. Storage and sequencing methods influenced microbial profiles: ethanol-stored samples exhibited higher diversity than frozen samples, and 16S sequencing detected lower diversity than shotgun. Helminths were detected via coprological microscopy in 71% of individuals, whereas metagenomic detection was inconsistent. This study provides new data on the microorganisms and their putative digestive functions in the gut of a folivorous primate, and highlights the pros and cons of different methodological choices when profiling host-microbiome and host-parasite interactions.

Animals

Candidate biomarkers for early Giardia duodenalis infection revealed by time-resolved secretome proteomics.

Giardia duodenalis is a zoonotic protozoan parasite that causes giardiasis in humans and other mammals. Early diagnosis remains challenging because current diagnostic methods, including microscopy and enzyme-linked immunosorbent assays (ELISAs), primarily detect established infections. Consequently, a critical diagnostic gap exists during the early stage of infection within the first 2-48 h following exposure. To address this limitation, we characterized the proteins released by in vitro-cultured G. duodenalis trophozoites under serum-free conditions and evaluated their potential as early diagnostic biomarkers. Proteomic analysis of culture supernatants collected during early trophozoite incubation identified 31,773 peptides corresponding to 2504 quantifiable proteins. Temporal profiling showed distinct secretion patterns, including proteins that peaked during the early stage, progressively accumulated over time, or remained persistently abundant throughout the incubation period. Based on their secretion characteristics and predicted immunogenic properties, five candidate biomarkers were selected for further evaluation. Polyclonal antibodies raised against selected candidates successfully detected the corresponding proteins in serum-free culture supernatants, providing preliminary evidence for their potential utility as early-stage diagnostic targets. These findings identify stage-associated candidate proteins that may serve as a resource for future early giardiasis diagnostic development, provide a valuable resource for investigating host-parasite interactions, and establish a foundation for future diagnostic assay development. However, further validation in clinical and biological samples is required to confirm their diagnostic applicability. SIGNIFICANCE: Giardiasis, caused by Giardia duodenalis, is a major diarrheal disease worldwide. Although enzyme-linked immunosorbent assays (ELISAs) provide rapid detection, their diagnostic utility is limited by the lack of biomarkers capable of identifying infection during its earliest stages, creating a critical gap in the detection of active infection within 2-48 h following exposure. Using data-independent acquisition proteomics, this study provides a time-resolved characterization of proteins released by G. duodenalis trophozoites into serum-free culture supernatants. Our findings reveal temporal secretion dynamics of protein secretion and identify candidate biomarkers with potential utility for the development of early-stage diagnostic assays pending rigorous biological and clinical validation. In addition, this proteomic resource provides a foundation for investigating host-parasite interactions and may facilitate the development of future point-of-care diagnostic strategies.

Giardiasis

Malaria: Factors affecting disease severity, immune evasion mechanisms, and reversal of immune inhibition to enhance vaccine efficacy.

Malaria is a complex parasitic disease caused by species of Plasmodium parasites. Infection with the parasites can lead to a spectrum of symptoms and disease severity, influenced by various parasite, host, and environmental factors. There have been some successes in developing vaccines against the disease recently, but the vaccine efficacies require improvement. Some issues associated with the difficulties in developing a sterile vaccine include high antigenic diversity, switching expression of the immune targets, and inhibition of immune pathways. Current vaccine research focuses on identifying conserved and protective epitopes, developing multivalent vaccines (including the whole parasite), and using more powerful adjuvants. However, overcoming the systematic immune inhibition and immune cell dysfunction/exhaustion may be required before high titers of protective antibodies can be achieved. Increased expression of surface molecules such as CD86 and MHC II on antigen-presenting cells and blocking immune checkpoint pathways (interactions of PD-1 and PD-L1; CTLA-4 and CD80) using small molecules could be a promising approach for enhancing vaccine efficacy. This assay reviews the factors affecting the disease severity, the genetics of host-parasite interaction, immune evasion mechanisms, and approaches potentially to improve host immune response for vaccine development.

Humans

Virulent Parasites Emerge in Hosts With Rising Temperatures.

Climate change is increasing the risk of emerging parasites. However, whether more virulent variants will spread during climate-driven outbreaks remains unclear. Here, we aimed to explore the short-term trajectory of parasite evolution-at the phenotypic and genomic scales-across environmentally relevant temperatures in a thermally mismatched host-parasite interaction. We experimentally evolved a wild parasitic bacterium (Leucobacter musarum), across the thermal range (20°C-30°C) and extremes (35°C) of Cabo Verde-the site of field collection-in a Caenorhabditis elegans host strain. Starting from a single bacterial isolate, we then tracked phenotypic and de novo genomic changes that arose across replicate populations following ten passages of experimental evolution. We found that at 25°C, warm for the host but an average temperature for the parasite, host-mediated selection favoured higher virulence and genomic diversification by the end of the experiment. At hot temperatures, towards the limit of host survival, virulence was maintained across all parasite populations. Parasites evolved at hot temperatures also displayed a latent virulence boost, deadlier once hosts experienced a heatwave. Patterns of molecular evolution were constrained to parallel changes in fewer loci at extreme temperatures. Our findings suggest that shifting environmental temperatures will leave phenotypic and genomic signatures on evolving parasites.

Animals

Comparative and systems analyses of Leishmania spp. non-coding RNAs through developmental stages.

Leishmania spp. is the etiological agent of leishmaniases, neglected diseases that seek to be eradicated in the coming years. The life cycle of these parasites involves different host and stress environments. In recent years, many studies have shown that several protein-coding genes are directly involved with the development and host interactions. However, little is still known about the role of non-coding RNAs (ncRNAs) in life cycle progression. In this study, we aimed to identify the genomic structure and function of ncRNAs from Leishmania spp. and to get insights into the repertoire of ncRNAs (RNAome) of this protozoan genus. We studied 26 strains corresponding to 16 different species of Leishmania. Our RNAome analysis revealed the presence of several ncRNAs that are shared among different species, allowing us to differentiate between subgenera as well as between species that are canonically related to visceral leishmaniasis. We also studied co-expression relationships between coding genes and ncRNAs which in the amastigote developmental stage for Leishmania braziliensis and Leishmania donovani revealed the presence of miRNA-like transcripts co-expressed with several coding genes involved in starvation, survival and histone modification. This work represents the first effort to characterize the Leishmania ssp. RNAome, supporting further approaches to better understand the role of ncRNAs in gene regulation, infective process, and host-parasite interaction.

RNA, Untranslated

Comparative genomic and proteomic analysis reveals orthogroup structured evolution of tick protease inhibitors.

Protease inhibitors (PIs) play central roles in regulating endogenous proteolysis and host-parasite interactions in ticks. However, the evolutionary architecture underlying their diversification across tick lineages remains insufficiently resolved. Here, we performed a genome-wide comparative analysis of predicted proteomes from 14 tick species to systematically characterize PI repertoires. In total, 4931 putative PIs were identified and grouped into 20 families using the MEROPS classification system. Further, PI families such as Antistasin, WAP-type, and Pacifastin, which have not previously been systematically reported in tick genomes, were classified. Orthogroup inference demonstrated that PI expansion is structured at the level of evolutionary lineages rather than uniformly across families. By stratifying orthogroups according to duplication burden and taxonomic conservation, we identified a broadly conserved single-copy core under strong purifying selection. Motif level analysis of serpin reactive center loops further revealed conservation of inhibitory specificity within single copy orthogroups and diversification of key functional residues in duplication-associated lineages. Integration of secretion prediction and tissue-resolved proteomics from Hyalomma anatolicum and Rhipicephalus microplus demonstrated that evolutionary stratification is reflected at the protein level. Together, these findings provide an orthogroup-resolved evolutionary framework linking duplication dynamics, molecular evolution, and tissue-level protein deployment. This integrative approach offers a systematic basis for prioritizing conserved and diversified PI lineages for future functional and anti-tick intervention studies.

Animals

Surface shaving proteomics reveals a parasite-encoded protein embedded in the spore filaments of Ameson portunus.

The surfaces of microsporidian spores are frequently adorned with filamentous appendages of unknown origin and function. Although some studies suggest that these structures may be host-acquired, the absence of identified parasite-encoded components has hindered our understanding of their biogenesis and role in infection. Here, we applied surface shaving proteomics to profile the surface-exposed proteins of Ameson portunus -a microsporidian pathogen causing severe myopathy in portunid crabs. Our analysis identified 120 candidate surface proteins. Nineteen of these were highly enriched by both direct shaving and SDS-assisted methods, representing a high-confidence surfome. Among these, a previously uncharacterized protein, designated 8-2.11, was confirmed via immunofluorescence assay and immunoelectron microscopy. It was expressed early in development stage and specifically localized to the spore wall and hair-like projections (HLPs) of microsporidia. Notably, polyclonal antibodies against recombinant 8-2.11 recognized a native protein in spores, specifically labeled the HLP structures, and showed no cross-reactivity with host cells. Our results provide the first evidence of a parasite-encoded protein that is integral to HLP formation, challenging the prevailing hypothesis that these surface filaments are solely host-derived. This study establishes surface shaving as a powerful tool for microsporidian research and highlights 8-2.11 as a promising candidate for future functional studies on spore surface biology and host-parasite interactions.

Animals

Preliminary screening of urinary host protein biomarkers for Schistosomiasis haematobium: A proteome profiling study identifying candidate diagnostic targets in school-aged children.

Schistosomiasis is a major public health challenge and a globally neglected tropical disease. Schistosoma haematobium, the causative agent of urogenital schistosomiasis, is endemic in African countries; with school-aged children ages 7-15 years being the most vulnerable population. Current diagnostic methods rely on microscopy to identify parasite eggs in urine; which is labor-intensive, requires specialized skills, and often lacks sensitivity, especially in mild infections. To address these limitations, we explored host disease-related biomarkers as a promising avenue for advancing diagnosis and detection. We recruited 135 children ages 7-15 years from Zanzibar, a known transmission hotspot, and used data-independent acquisition (DIA) proteomics combined with machine learning to identify potential host protein biomarkers in urine samples from individuals infected with Schistosoma haematobium. Proteomic analysis identified 823 common host proteins in urine samples from the infected group. Machine learning algorithms highlighted candidate discriminative proteins; which were validated using enzyme-linked immunosorbent assays (ELISA). Machine learning emphasized SYNPO2, CD276, α2M, LCAT, and hnRNPM as the most discriminating biomarkers for Schistosoma haematobium infection. ELISA validation confirmed the differential expression trends of these proteins, while machine learning further validated LCAT and α2M, underscoring their diagnostic potential. Our study focused on host-derived proteins and identified key urinary protein biomarkers associated with Schistosoma haematobium infection, and offers new insights into host-parasite interactions and potential tools for non-invasive diagnostics. While validated in African pediatric populations from transmission hotspots, this host-protein approach inherently overcomes geographic limitations of parasite-based diagnostics; which is a critical advantage for surveillance in non-endemic regions where imported cases threaten gains toward elimination. These findings lay the groundwork for developing novel diagnostic approaches that could significantly improve the detection and surveillance of schistosomiasis, particularly in high-risk populations.

Humans

A paradoxical population structure of var DBLα types in Africa.

The var multigene family encodes Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), central to host-parasite interactions. Genome structure studies have identified three major groups of var genes by specific upstream sequences (upsA, B, or C). Var with these ups groups have different chromosomal locations, transcriptional directions, and associations with disease severity. Here we explore temporal and spatial diversity of a region of var genes encoding the DBLα domain of PfEMP1 in Africa. By applying a novel ups classification algorithm (cUps) to publicly-available DBLα sequence datasets, we categorised DBLα according to association with the three ups groups, thereby avoiding the need to sequence complete genes. Data from deep sequencing of DBLα types in a local population in northern Ghana surveyed seven times from 2012 to 2017 found variants with rare-to-moderate-to-extreme frequencies, and the common variants were temporally stable in this local endemic area. Furthermore, we observed that every isolate repertoire, whether mono- or multiclonal, comprised DBLα types occurring with these frequency ranges implying a common genome structure. When comparing African countries of Ghana, Gabon, Malawi, and Uganda, we report that some DBLα types were consistently found at high frequencies in multiple African countries while others were common only at the country level. The implication of these local and pan-Africa population patterns is discussed in terms of advantage to the parasite with regards to within-host adaptation and resilience to malaria control.

Plasmodium falciparum

Tropilaelaps mercedesae: an emerging global threat to apiculture - a comprehensive review.

Honey bees (Apis spp.) are key pollinators in agricultural and natural ecosystems; however, their populations are declining due to multiple interacting stressors and their synergistic effects, including parasitic mites. While Varroa destructor is widely recognized as the primary global driver of colony losses, mites of the genus Tropilaelaps, particularly Tropilaelaps mercedesae, are emerging as a serious and still underestimated threat. Native to Asia and naturally associated with wild hosts such as Apis dorsata, T. mercedesae has successfully transitioned to managed Apis mellifera colonies and is now widespread across much of Asia. Recent reports from Central Asia and the Caucasus and western Eurasian regions (including Georgia and Russia) indicate that this species is undergoing an ongoing westward expansion toward Europe. Its biological traits-including an extremely short reproductive cycle, obligate dependence on sealed brood, high dispersal capacity, and the potential to transmit viruses such as deformed wing virus (DWV)-facilitate rapid population growth and severe colony-level damage, particularly in A. mellifera, which lacks effective behavioral defenses against this mite. This review synthesizes current knowledge on the taxonomy, morphology, life cycle, host-parasite interactions, geographic distribution, and spread of Tropilaelaps mites, with emphasis on T. mercedesae. It also evaluates available diagnostic approaches, including brood-based methods, adult bee-based methods, and natural mite-fall techniques. Furthermore, evidence on chemical and biotechnical control strategies is summarized, and their strengths, limitations, and integration within an Integrated Pest Management (IPM) framework are discussed. Overall, current findings highlight the urgent need to strengthen surveillance, standardize diagnostic protocols, and develop sustainable control strategies to prevent the global spread of Tropilaelaps mites.

A. mellifera

Disentangling host genetic variation for avoidance and resistance to pathogens.

BACKGROUND: Hosts can use avoidance (e.g., behavior) to reduce their contact rates with pathogens; after contact, they can use resistance (e.g., immunity) to reduce the establishment and proliferation of an infection. Because both defenses preserve host fitness and reduce pathogen fitness, we expect that their epidemiological and evolutionary effects will be interdependent. This study used a two-locus model to understand the evolution of allelic associations (i.e., linkage disequilibrium or LD) between genes determining levels of avoidance and resistance in the presence of an infectious disease or a parasite. RESULTS: We found that polymorphism in both avoidance and resistance was possible, but only for a limited range of parameter values. At equilibrium within these polymorphic populations, avoidance and resistance alleles were negatively associated (i.e., in negative LD). However, most commonly, polymorphism was only stably maintained at one defense locus, and the other locus became fixed for one allele. CONCLUSIONS: The model shows that avoidance and resistance are likely to influence each other's evolution because of their joint effects on infection and their costs; however, predictions about their relationship are not necessarily straightforward or intuitive. For example, avoidance and resistance may be more likely to covary across than within populations.

Animals

Parasites and allergies: a complex bidirectional relationship from evolutionary origins to modern therapeutics.

Parasites and allergic diseases are linked by a complex, bidirectional relationship shaped by long-term host-parasite coevolution. This review discusses how different parasites may either promote or attenuate allergic responses through immunological, epithelial, and microbiome-mediated mechanisms. IgE-mediated immunity, mast cell activation, eosinophilia, and pruritus may have evolved as protective responses against helminths and blood-feeding ectoparasites. In contrast, modern allergies may partly reflect misdirected responses to harmless environmental antigens. The effects of parasites on allergy are not uniform and depend on parasite type, infection site, exposure intensity and chronicity, host immune status, and the degree of host-parasite adaptation. Protozoa such as Giardia intestinalis may contribute to food allergy-related manifestations by disrupting the intestinal barrier, altering gut microbiota composition, and modifying mucosal immune responses, particularly in atopic individuals. In contrast, selected helminths may attenuate allergic inflammation by inducing regulatory T and B cells, anti-inflammatory cytokines, antigen-presenting cell modulation, and IgG4-associated mechanisms that can limit IgE-mediated effector responses. Molecular similarities between parasite-derived antigens and environmental allergens, including conserved protein families and carbohydrate epitopes, may contribute to cross-reactive IgE responses and complicate allergy diagnostics. Therefore, current research is shifting from live helminth therapy toward defined parasite-derived molecules and immunomodulatory pathways that may inspire safer and more controlled therapeutic strategies. A clearer understanding of parasite-allergy interactions may improve diagnostic interpretation and support the development of new approaches to the management of allergic disease.

Humans

Snail immunity to schistosomes: insights from omics studies.

Schistosomiasis is a serious public health concern, with transmission facilitated by a small number of freshwater snail intermediate host species. Infection outcomes vary greatly across the primary vector genera, Biomphalaria (for Schistosoma mansoni), Bulinus (for S. haematobium), and Oncomelania (for S. japonicum), even within species, ranging from full resistance to high compatibility. Omics methods have altered this field by correlating host genotype, baseline immunological status, and time-resolved responses to whether invading miracidia are eliminated or develop sporocysts. Evidence from genomes, transcriptomics, proteomics, and epigenomics suggests that resistance is frequently primed prior to exposure. However, the clearest divergence between resistant and susceptible trajectories occurs during a small early window (<12-48&#x202f;h) after penetration. During this time, recognition, hemocyte recruitment, and soluble effector deployment either come together quickly or are delayed and guided by parasite-derived modulators. Established infections cause the host to adapt to chronic conditions through immune regulation, metabolic reprogramming, tissue and neuroendocrine remodeling, microbiome modification, and parasite castration. Comparative genomics reveals that each vector genus has evolved its own immunogenomic profile, which includes lineage-specific expansions of recognition and effector gene families. Together, these findings can help with field surveillance and intervention by providing molecular compatibility markers, functional tools for testing candidate genes, and tactics that target parasite-derived immune modulators. Integrated multi-omics approaches are a top priority, yet they are still limited in snail vectors compared to other disease vector systems.

Animals

Comparative in silico analysis of Apis mellifera immune responses to Varroa destructor and Tropilaelaps mercedesae: Common and mite-specific molecular signatures.

Parasitic mites Varroa destructor and Tropilaelaps mercedesae represent major threats to global honey bee (Apis mellifera) health and productivity, yet comparative molecular insights into host responses remain limited. To address this, we systematically compiled published studies (2015-2025) reporting genes associated with honey bee interactions with V. destructor (11 studies, 87 genes), T. mercedesae (4 studies, 35 genes), and hygienic behavior (6 studies, 44 genes). Gene identifiers were harmonized to the Amel_HAv3.1 genome assembly, yielding three non-redundant sets: 64 Varroa-associated, 34 Tropilaelaps-associated, and 44 hygienic behavior-associated genes. Venn analysis identified 10 overlapping genes (including A0A088A8D5, A0A088ADL8, ABAE_APIME, Def1, Def2, Gapdh, HYTA_APIME, Imd, LOC726783, and Vg), suggesting conserved defense mechanisms, while 41 and 24 genes were uniquely associated with Varroa and Tropilaelaps, respectively. Enrichment analyses revealed Varroa-responsive genes were enriched in immune processes, chitin catabolism, and signaling pathways (Toll/Imd, MAPK, Wnt). Tropilaelaps-associated genes were enriched for antibacterial defense and stress response, with Toll/Imd signaling as the sole significantly enriched pathway. Overlapping genes reinforced core innate immunity activation. Protein-protein interaction network centrality analysis identified key hub genes: Def1, HYTA_APIME, ABAE_APIME, PPO, Imd, PGRP-LC, Vg for Varroa; and ACPH1_APIME, MRJP1, Vg, LOC726783 for Tropilaelaps. Results demonstrate that, despite differences in mite biology, honey bees show a conserved immune response against both parasites, centered on antibacterial defense, humoral immunity, and activation of the Toll/Imd pathway. Although limited by the in-silico nature and research asymmetries reflecting Tropilaelaps' emergence, this curated resource establishes a comprehensive framework for elucidating shared and distinct molecular defense mechanisms. Ultimately, this approach prioritizes diagnostic markers and candidate genes for functional validation and breeding strategies to enhance colony resilience against mite&#x2011;driven disease globally.

Animals

Can host genetics transform the sustainable control of tropical theileriosis? Insights from the Tick-Theileria interface.

Tropical theileriosis, caused by the tick-transmitted apicomplexan parasite Theileria annulata, remains a major constraint on cattle production across North Africa, the Mediterranean basin, the Middle East and South Asia. Current control depends on acaricides, the theilericidal drug buparvaquone and live attenuated schizont vaccines, but acaricide resistance, buparvaquone-resistance mutations and the logistical demands of vaccination are eroding the sustainability of these tools. Host genetics offers a complementary and durable alternative. Indigenous Bos indicus breeds are consistently more resistant to ticks and tolerate T. annulata infection better than exotic Bos taurus cattle, and this advantage has a measurable heritable component. Unlike previous reviews, which treat tick resistance, T. annulata immunobiology and livestock genomic selection as separate subjects, we integrate all three and assess host genetics specifically against the failure modes of current control. We review the tick, parasite and host interface, the evidence for natural resistance, and the genetic and immunological mechanisms involved, including signal-regulatory protein, bovine major histocompatibility complex class II and inflammatory pathway genes. We then assess whether genomic selection, multi-omics, machine learning and gene editing can translate these mechanisms into resistant cattle, and we weigh the biological, economic and infrastructural barriers to implementation. The evidence indicates that host genetics will not replace existing control but could reduce reliance on acaricides and chemotherapy. That contribution remains prospective rather than demonstrated: no resistance marker for T. annulata has yet been validated, prediction accuracies are moderate and transfer poorly between breeds, and no endemic production system has implemented selection for resistance.

Animals

Lineage-specific targets of positive selection in three leaf beetles correspond with defence capacity against their shared parasitoid wasp.

Parasitoid wasps are major causes of mortality of many species, making host immune defences a common target of adaptive evolution, though such targets outside model species are poorly understood. In this study, we used two tests of positive selection to compare across three closely related Galerucella leaf beetles that show substantial differences in their phenotypic response to the shared parasitoid wasp Asecodes parviclava, their main natural enemy. Using a codon-based test, which detects excess amino acid fixations per locus along each species' lineage, we found more evidence of positive selection on parasitoid-relevant immune genes in the species with the strongest immunocompetence (G. pusilla) compared with the species having weaker immunocompetence (G. tenella and G. calmariensis). Moreover, genes coding for the early phases in the immune response cascade were predominantly among the positively selected immune genes, providing targets for future functional genomic study to pin-point connections between genotypic and phenotypic differences in defences towards a parasitoid wasp. In contrast, genome-wide analyses of the haplotype frequency spectrum, which quantify selection over recent evolutionary time scales, revealed similar signatures of positive selection on immune genes across species. These results advance the field of host-parasitoid dynamics by providing novel insights into the tempo and mode of insect host evolutionary dynamics, and offering a framework for making genotype to phenotype connections for immunocompetence phenotypes.

Animals