Search Results (238)

Renicolid digeneans parasitise aquatic birds. In molecular trees, they are divided into three clades, one of which, the ‘duck clade’, parasitises anatids. Renicola mollissima, a member of this clade, parasitises sea ducks, mainly eiders. Its life cycle remains unknown. We verified the diagnosis of R. mollissima using integrated morphological and molecular data and provided the first information on its life cycle in northern Palaearctic. We proved that intramolluscan stages of R. mollissima, previously known as Cercaria pacifica 2, develop in intertidal snails Littorina squalida and L. saxatilis. We provided a detailed morphological description of cercariae and adults of R. mollissima and a discriminative analysis with closely related species. Molecular data demonstrated an amphiboreal distribution of R. mollissima and the existence of a single population in Europe and the North Pacific. Using molecular methods, we also found metacercariae of an unknown renicolid species from the ‘duck clade’, designated as Cercaria cf. nordica I, in subtidal mussels of the Barents Sea. All individuals of C. cf. nordica I examined in our study were represented by the same haplotype. We discuss possible ways of formation of this phylogeographic structure, the composition of the ‘duck clade’ and the evolutionary pathways of the family Renicolidae. Full article

Horizontal gene transfer (HGT), the non-Mendelian transfer of genetic material between organisms, is relatively frequent in prokaryotes, whereas its extent among eukaryotes remains unclear. Here, we raise the hypothesis of a possible cross-phylum HGT event involving 5S ribosomal DNA (rDNA). A specific type of 5S rDNA sequence from the anuran Xenopus laevis was highly similar to a 5S rDNA sequence of the genome of its flatworm parasite Protopolystoma xenopodis. A maximum likelihood analysis revealed phylogenetic incongruence between the gene tree and the species trees, as the 5S rDNA sequence from Pr. xenopodis was grouped along with the sequences from the anurans. Sequence divergence analyses of the gene region and non-transcribed spacer also agree with an HGT event from Xenopus to Pr. xenopodis. Additionally, we examined whether contamination of the Pr. xenopodis genome assembly with frog DNA could explain our findings but found no evidence to support this hypothesis. These findings highlight the possible contribution of HGT to the high diversity observed in the 5S rDNA family. Full article

Indigenous people possess unique health literacy issues and challenges with preventing infectious diseases. This research assessed the baseline knowledge and misinformation in the Semai indigenous subgroup in Perak state, Malaysia, and the impact of a culturally adapted health education intervention. A single-group pre-test/post-test design was used with 156 participants ranging from 7 to 69 years old, predominantly children. The survey addressed key issues of head lice, intestinal parasites, tuberculosis (TB), handwashing, and germ transmission. An interactive, multi-station health education session in the local language produced a significant increase in overall knowledge (mean score increased from 3.17 to 3.83 out of 5, p < 0.0001), with the largest increase among the adult group aged 31–50 years. This was most notable for handwashing knowledge, which had the greatest increase, and misconceptions about intestinal worms and head lice remained. Differences in outcome by age suggest the need for targeted educational strategies, particularly for teenagers and elderly individuals who achieved less gain. The results support the effectiveness of culturally tailored, community-based health education in promoting the awareness of disease among indigenous communities. The drawbacks are convenience sampling, the child dominance of the sample, and the short-term follow-up. Future emphasis should be placed on long-term, community-based intervention using culturally tailored content and digital media. Full article

Background: Parasitic worm infections remain among the most prevalent and neglected health issues worldwide, affecting both humans and animals. Toxocariasis, caused by Toxocara spp., is a widespread zoonosis with significant public health and economic implications. Current anthelmintic treatments show limited efficacy, particularly against tissue-migrating larvae, underscoring the urgent need for new therapeutic options. This study aimed to evaluate the anthelmintic potential of H₁ antihistamines as repurposed drug candidates against Toxocara canis. Methods: Twenty-two H₁ antihistamines were screened for larvicidal activity against infective third-stage (L3) larvae of T. canis. Larval motility and morphology were assessed, and compounds with the highest efficacy were further investigated using density functional theory (DFT) to explore their electronic properties. Molecular docking simulations were also performed to predict interactions with T. canis β-tubulin. Results: Promethazine and rupatadine exhibited significant larvicidal effects, surpassing albendazole in reducing larval motility and inducing a distinct contorted morphology not observed in control or albendazole-treated larvae. DFT analyses suggested a strong electron-acceptor capacity, indicating a potential redox-based mechanism of action. Docking studies revealed favorable binding to the colchicine site of T. canis β-tubulin. Conclusions: This is the first report of larvicidal activity of antihistamines against T. canis, supporting their potential as repurposed therapeutic agents for the treatment of zoonotic helminthiases, particularly those caused by tissue-migrating nematodes. Full article

A recent high-throughput screening of the NatureBank marine extract library (7616 samples) identified an extract from the Australian marine sponge Agelas axifera with in vitro activity against an economically important parasitic nematode, Haemonchus contortus (barber’s pole worm). The bioassay-guided fractionation of the CH₂Cl₂/MeOH extract from A. axifera led to the purification of a new diterpene alkaloid, agelasine Z (1), together with two known compounds agelasine B (2) and oxoagelasine B (3). Brominated compounds (–)-mukanadin C (4) and 4-bromopyrrole-2-carboxylic acid (5) were also isolated from neighbouring UV-active fractions. All compounds, together with agelasine D (6) from NatureBank’s pure compound library, were tested for in vitro anthelmintic activity against exsheathed third-stage (xL3s) and fourth-stage larvae (L4s) of H. contortus and young adult Caenorhabditis elegans. Compounds 1, 2 and 6 induced an abnormal “skinny” phenotype, while compounds 2 and 6 also reduced the motility of H. contortus L4s by 50.5% and 51.8% at 100 µM, respectively. The minimal activity of agelasines against C. elegans young adults suggests a possible species-specific mechanism warranting further investigation. For the first time, the unexpected lability of agelasine H-8′ was explored using kinetic studies, revealing rapid deuterium exchange in MeOH-d₄ at room temperature. Full article

Background: A comparative analysis was conducted between two immunisation protocols using different amounts of protein extracts from adult Haemonchus contortus worms, purified by thiol-Sepharose chromatography (625 μg/animal vs. 200 μg/animal). These protocols involved either five or two inoculations of the immunogen, respectively. Methods: To evaluate the level of immunoprotection, animals were challenged with L3 of H. contortus two weeks after the last inoculation of the immunogen and humanely sacrificed at 8 weeks post-infection. Parasitological, biopathological, and serological parameters were monitored through the experiment. Parasite burden, abomasal-specific antibody responses, and histopathological changes were determined at the end of the trial. Results: The immunisation protocols resulted in similar reductions in cumulative faecal egg counts (60.5–64.9%) and the total worm burden (47.5–50%) compared to non-immunized (control) animals. Overall, these parasitological data showed an early recovery of the haematocrit (PCV) after challenge in the immunised groups relative to control. Similarly, levels of H. contortus-specific IgG and IgA antibodies increased in both the serum and gastric mucus of immunised groups. Conclusions: These findings represent a further step towards the potential application of this type of immunogen under field conditions, as protective responses (associated with a reduction in faecal egg output) were achieved using a simplified protocol, with lower immunogen doses and fewer inoculations required to induce immunoprotection, thereby mitigating the pathological effects of the parasite and reducing its ability to spread and infect susceptible hosts. Full article

Haemonchosis caused by the parasitic worm Haemonchus contortus is a major threat to cattle and other ruminants and imposes significant economic losses in the livestock industry. Different medications have been reported; however, these are not reliable now due to mass drug resistance. The current study investigates potential inhibitors of two H. contortus proteins: glutathione S-transferase (GST) and beta-tubulin isotype 1. GST helps the parasite to detoxify harmful substances, while beta-tubulin is essential for the cell division and structure. By using computational approaches, natural compounds were identified to inhibit the selected proteins. The 3D structures of GST and β-tubulin isotype 1 were prepared, and pharmacophore models were generated to search the Molport natural compound library. The lowest binding energy ranged from −6.7 to −10.4 Kcal/mol. Post-docking interactional analyses revealed that Glu45, Arg46, Cys126, Gln131, Lys252, Asn247, and Arg251 residues were the most common interacting residues in β-tubulin isotype 1. Similarly, in GST, Leu99, Asn100, Arg103, Lys107, Glu162, and Met163 were the most common interacting residues. In conclusion, extensive computational analyses including virtual screening, docking, and MD simulations revealed that the compound Molport-039-195-358 might have the ability to control haemonchosis by targeting GST and β-tubulin isotype 1. The in silico studies identified potent compounds by targeting GST and β-tubulin isotype 1 against Haemonchus contortus. The reported findings provide a foundation for the development of novel anthelmintic therapies. Full article

Orthonectids are a group of highly simplified worm-like parasites that are placed within Lophotrochozoa by multigene mitochondrial and nuclear phylogenies. However, their exact position within Lophotrochozoa is uncertain due to the high rate of molecular evolution and putative long branch attraction artifacts. To examine the phylogenetic placement of orthonectids, we applied an alternative approach that takes into account rare evolutionary events (gene order rearrangements in mitochondrial DNA and individual changes in mitochondrial proteins) with an assessment of their probabilities based on a reference sequence database (RefSeq, NCBI). This approach strongly supports the branching of orthonectids among annelids, but does not conclusively resolve their position among the annelid taxa. Full article

Dictyocaulosis is a parasitic disease that affects ungulate species, including red deer (Cervus elaphus). The genus Dictyocaulus comprises eighteen species, but only four have been reported to infect red deer. The disease is characterized by respiratory tract infection, particularly in the lungs, bronchi, and bronchioles, leading to inflammatory and hemorrhagic microscopic lesions, as well as emphysema and edema. The biological cycle involves a female ovipositing larvated eggs in the bronchi and trachea, which are expelled to the exterior through coughing or feces, releasing L1 into the environment. In this study, 106 adult red deer were collected from seven locations in Extremadura (Spain). Eight positive lungs were initially assessed by morphological identification, revealing a mean intensity of 13.3 adult worms per infected lung, with a global decrease to an average of 1.8 adult worms per sampled lung. The presence of adult worms in the upper and middle respiratory tract was confirmed through anatomopathological analysis. Molecular identification was performed by sequencing the COI gene. The results indicated the presence of three genetic groups, supported by significant subdivision using the ɸ_ST measure. D. cervi and D. viviparus exhibited their respective matrilineal ancestry, while D. eckerti and D. cervi demonstrated matrilineal sharing. Consequently, the possibility of introgression between these two species was suggested. Although D. viviparus had previously been identified in the same Spanish region based on morphological characteristics, D. cervi and D. eckerti were reported for the first time in the explored geographic area. Full article

Soil-transmitted helminths (STHs) are parasitic nematodes that infect humans, particularly in tropical and subtropical regions, where they contribute substantially to neglected tropical diseases (NTDs). Among them, hookworms (Ancylostoma duodenale, Necator americanus and Ancylostoma ceylanicum) cause substantial morbidity, leading to anaemia, malnutrition, and developmental impairment. Despite the global impact of hookworm disease, genomic research on A. duodenale has lagged behind that of other hookworms, limiting comparative and molecular biological investigations. Here, we report the first chromosome-level reference genome of A. duodenale, assembled from a single adult specimen archived in ethanol at −20 °C for more than 27 years. Using third-generation sequencing (PacBio Revio, Menlo Park, CA, USA, Oxford Nanopore, Oxford, UK), Hi-C scaffolding, and advanced computational tools, we produced a high-quality 319 Mb genome, filling a critical gap in hookworm genomics. Comparative analyses with N. americanus and the related, free-living nematode Caenorhabditis elegans provided new insights into genome organisation, synteny, and specific adaptations. While A. duodenale exhibited strong chromosomal synteny with N. americanus, its limited synteny with C. elegans highlights its distinct parasitic adaptations. We identified 20,015 protein-coding genes, including conserved single-copy orthologues (SCOs) linked to host–pathogen interactions, immune evasion and essential biological processes. The first comprehensive secretome analysis of A. duodenale revealed a diverse repertoire of excretory/secretory (ES) proteins, including immunomodulatory candidates predicted to interact with host structural and immune-related proteins. This study advances hookworm genomics, establishes a basis for the sequencing of archival specimens, and provides fundamental insights into the molecular biology of A. duodenale. The genomic resource for this hookworm species creates new opportunities for diagnostic, therapeutic, and vaccine development within a One Health framework. It complements recent epidemiological work and aligns with the WHO NTD roadmap (2021–2030) and Sustainable Development Goal 3.3. Full article

This paper presents an analysis of helminth diversity in reptiles in eight provinces of the Middle Volga region (European Russia) based on the dataset recently published in the GBIF as the Darwin Core Archive. The dataset contains up-to-date information on the occurrence of parasitic worms in lizards and snakes and summarizes the records obtained during long-term helminthological studies conducted in 1996–2024. It includes 8576 helminth occurrence records in nine reptile species inhabiting the Middle Volga region. All helminth occurrence records are georeferenced. In total, we present data on 45 parasitic worm species, including 4 species of cestodes, 21 species of trematodes, 16 species of nematodes, and 4 species of acanthocephalans. The richest helminth fauna was found in Natrix natrix (26 species), Lacerta agilis (21), Natrix tessellata (16), and Vipera berus (15). Less diverse is the helminth fauna in Anguis colchica (8 species), Zootoca vivipara (7), Vipera renardi (6), Coronella austriaca (5), and Eremias arguta (3). The diversity of helminths in reptiles of the Middle Volga region does not reach its maximum compared to other European countries. Most helminth species found in lizards and snakes of the studied region belong to the Palearctic faunal complex (25 species). Eight species of parasites have a Holarctic distribution. Seven helminth species parasitize reptiles only in Europe. Five species of parasites are cosmopolitan. Of the 45 species of helminths found in reptiles, 3 species have medical and veterinary significance as causative agents of dangerous helminthiasis. Data on the diversity and distribution of parasitic worms in reptiles of the Middle Volga region remain incomplete, so further observations may provide new occurrence records of helminths and expand the knowledge about their hosts. Full article

Schistosomes are intravascular parasitic worms that cause the debilitating tropical disease schistosomiasis, affecting >200 million people worldwide. How the worms survive within the body of immunocompetent hosts for many years is unclear. Here, using chromatography and mass spectrometry, we report on the ex vivo ability of adult Schistosoma mansoni worms to modulate the levels of 27 small molecule (often immunomodulatory) metabokines in murine plasma. Schistosomes significantly alter the relative amounts of most (16) of these molecules. Three (inosine, genistein, and glucose) are significantly decreased in the presence of the parasites. While levels of several immunomodulatory metabolites from the kynurenine pathway (kynurenine, kynurenic acid, and xanthurenic acid) remain unchanged, levels of anthranilate (an endogenous regulator of innate immunity) are significantly increased. Of particular interest are increases in levels of metabolites that are known to skew immune responses in a manner that is seen following natural schistosome infection, such as by promoting Th2 immunity (succinate), Treg generation (lactate) and M2 macrophage polarization (lactate and succinate). In addition, significant increases are also observed for 2-hydroxyglutarate, adenine, hypoxanthine, xanthine, myoinositol, betaine and N-acetylglucosamine. Each of these compounds can have immunosuppressive effects that could impact host immunological status and contribute to schistosome survival. Full article

Bobcats (Lynx rufus) are an iconic North American predator; however, there is limited knowledge regarding their associated parasites. In this case study, we used a metagenomic approach to identify associated viruses and helminth species from a deceased bobcat. We determined the full mitochondrial genome of the bobcat and three helminths, i.e., tapeworm (Taenia sp.), stomach worm (Physaloptera sp.), and lung worm (Metathelazia sp.). Furthermore, we identified four circovirids; two (identified in a tapeworm and fecal swab) are members of the genus Circovirus and share 96.7% genome-wide identity between isolates and 87.4–88.6% identity with members of the species Circovirus miztontli. These appear to infect vertebrate species common to the Sonoran Desert, which could be a rodent preyed upon by the bobcat, and/or bobcat itself. The other two circovirids are novel members of the genus Cyclovirus (both identified in a tapeworm), one sharing 99.8% with those in the species Cyclovirus misi from a rodent and the other <67.3% with all other Cycloviruses. Our data support that these two Cycloviruses are likely tapeworm-infecting; however, more studies are needed to confirm the host. These findings enhance our understanding of viruses and helminths in bobcats, emphasizing the need for further research to unravel the ecology of parasites in these elusive predators. Full article

Schistosomiasis, a neglected tropical disease caused by parasitic worms of the genus Schistosoma and transmitted through freshwater snails, affects over 200 million people worldwide. Climate change, through rising temperatures, altered rainfall patterns, and extreme weather events, is influencing the distribution and transmission dynamics of schistosomiasis. This scoping review examines the impact of climate change on schistosomiasis transmission and its implications for disease control. This review aims to synthesize current knowledge on the influence of climate variables (temperature, rainfall, water bodies) on snail populations, transmission dynamics, and the shifting geographic range of schistosomiasis. It also explores the potential effects of climate adaptation policies on disease control. The review follows the Arksey and O’Malley framework and PRISMA-ScR guidelines, including studies published from 2000 to 2024. Eligible studies were selected based on empirical data on climate change, schistosomiasis transmission, and snail dynamics. A two-stage study selection process was followed: title/abstract screening and full-text review. Data were extracted on environmental factors, snail population dynamics, transmission patterns, and climate adaptation strategies. Climate change is expected to increase schistosomiasis transmission in endemic regions like Sub-Saharan Africa, Southeast Asia, and South America, while some areas, such as parts of West Africa, may see reduced risk. Emerging hotspots were identified in regions not currently endemic. Climate adaptation policies, such as improved water management and early warning systems, were found effective in reducing transmission. Integrating climate adaptation strategies into schistosomiasis control programs is critical to mitigating the disease’s spread, particularly in emerging hotspots and shifting endemic areas. Full article

Fine nematodes of the family Capillariidae parasitize various organs and tissues in fish, amphibians, reptiles, avians, and mammals. Currently classified into more than 20 genera, these nematodes are primarily distinguished based on the caudal structures of male worms. Morphological and molecular analyses were conducted on 15 mammal-parasitic species belonging to the genera Aonchotheca (A. putorii, A. suzukii n. sp., A. suis n. comb. (syn. Capillaria suis), A. riukiuensis, and A. bilobata), Pearsonema (P. neoplica n. sp., P. feliscati, P. iharai n. sp., and P. toriii n. sp.), Liniscus (L. himizu), Calodium (C. hepaticum), Echinocoleus (E. yokoyamae n. sp.), and Eucoleus (E. kaneshiroi n. sp., E. aerophilus, and Eucoleus sp.), using specimens from various wild and domestic animals in Japan and brown rats in Indonesia. As demonstrated in this study, nearly complete SSU rDNA sequencing is a powerful tool for differentiating closely related species and clarifying the phylogenetic relationships among morphologically similar capillariid worms. Additionally, most capillariid worms detected in dogs and cats are suspected to be shared with their respective wildlife reservoir mammals. Therefore, molecular characterization, combined with the microscopic observation of these parasites in wildlife mammals, provides a robust framework for accurate species identification, reliable classification, and epidemiological assessment. Full article