Schistosomosis in animals due to Schistosoma spindale significantly burdens India’s livestock economy because of high prevalence and morbidity and is mostly underdiagnosed from the lack of sensitive tools for field-level detection. This study aimed to clone, express the 22.6-kDa tegument protein of S. spindale (rSs22.6kDa) and to utilise it in a dot enzyme-linked immunosorbent assay for serodiagnosis. RNA was extracted from adult worms recovered from the mesenteries of slaughtered cattle to amplify the gene encoding the 22.6-kDa protein. In silico analysis revealed the protein’s secondary structure, consisting of 190 amino acids forming alpha helices (47.89%), extended strands (17.37%), beta turns (8.95%), and random coils (25.79%), with α helices and β sheets in the tertiary structure. Two conserved domains were noted: an EF-hand domain at the N-terminus and a dynein light-chain domain at the C-terminus. Phylogenetic studies positioned the S. spindale sequence as a sister clade to Schistosoma haematobium and Schistosoma bovis. The gene was cloned into a pJET vector and transformed into Escherichia coli Top 10 cells, with expression achieved using a pET28b vector, BL21 E. coli cells, and induction with 0.6 mM isopropyl-β-d-thiogalactopyranoside. The protein’s soluble fraction was purified using nickel-chelating affinity chromatography, confirmed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and immunoblotting, identifying a distinct immunodominant 22.6-kDa protein. The diagnostic utility was validated using a dot enzyme-linked immunosorbent assay which demonstrated a of sensitivity of 89.47% and specificity of 100%. The study records for the first time the prokaryotic expression and evaluation of the 22.6-kDa tegumental protein of S. spindale, highlighting its potential as a diagnostic antigen for seroprevalence studies in bovine intestinal schistosomosis.

This study aimed to determine the prevalence of gastrointestinal parasites in alpacas on selected farms in Poland. In July and August 2019 and August 2021, 223 samples from six commercial farms were examined using coproscopic techniques. The total percentage of alpacas infected with intestinal parasites was 57.7%. Eggs of Nematodirus sp. were found in 28.9%, Trichostrongylus sp. in 15.5%, Strongyloides sp. in 13.4%, Camelostrongylus sp. in 11.3%, other strongyle-type in 12.4%, Trichuris sp. in 3.1%, Capillaria spp. in 2.1%, Oesophagostomum sp. in 1.0% and eggs of Moniezia sp. in 1.0% of individuals. Oocysts of Eimeria macusaniensis were found in 8.2%, Eimeria sp. in 4.1%, and Cryptosporidium sp. in 3.1% of animals. Redundancy analysis showed that parasites and their number in faeces were related to the individual’s country of origin, sex and age. Females had significantly more eggs of parasites than males. More significant parasite infection was recorded in younger individuals. Moreover, the most infected were individuals from Germany. Some of the described parasites in tested alpacas have zoonotic potential. Due to the possibility of introducing parasites native to alpacas and acquiring species parasitising wild and farmed animals in Europe, permanent veterinary monitoring of animals imported from other regions is necessary.

In the winter of 2022–2023, hundreds of the Atlantic puffins (Fratercula arctica) appeared dead in the coast of the Canary Islands, a rare event considering their cold-living habits, normally occupying the North Atlantic Ocean. In this work, investigation about the parasites present in the Atlantic puffins found in the biggest islands of the Archipelago was carried out from a population portion. Necropsies of 39 birds were made and, during the examination of the urinary tracts, helminths were found. Morphoanatomical analysis under microscope allowed to identify them into Renicola genus with high similarity to Renicola sloanei. After that, DNA was extracted and NADH dehydrogenase subunit 1 gene were amplificated by a polymerase chain reaction method followed by sequencing and phylogenetic analysis. The molecular results demonstrated that in fact R. sloanei was the helminth parasite present in the urinary tracts of the Atlantic puffins found in the Canary Islands.

Acanthocephalans are obligatory endoparasites that often alter the phenotype of their invertebrate intermediate host to facilitate trophic transmission to their final vertebrate host. Acanthocephalus anguillae, a widespread parasite of European freshwater fishes and isopod Asellus aquaticus, was recently discovered also in Postojna-Planina Cave System (Slovenia) parasitising olms (Proteus anguinus) and cave populations of A. aquaticus. This setting offers a unique opportunity to investigate potential fine-tuning of parasitic manipulations to the specifics of the highly divergent subterranean environment where some common phenotypic alterations lose functionality, but others might gain it. We measured three behavioural traits: movement activity, shelter-seeking, and response to light of infested and uninfested isopods from surface and cave populations. All behaviours were quantified from 1-h video-recordings via video-tracking isopod’s movement in empty or custom modified (half-sheltered/half-illuminated) Petri dishes. Infested isopods of both populations spent significantly less time sheltering and were significantly less photophobic than uninfested ones, whereas the activity of isopods was not altered. However, we observed almost no cave-specific responses upon infestation in the two altered behaviours. It seems phenotypic alterations are not particularly fine-tuned to the subterranean environment and its hosts, and likely still reflect the parasite’s surface origin.

Saccocoelioides is a genus within the family Haploporidae and is distributed throughout the Americas. The recent application of molecular techniques has facilitated the reorganization of this genus and the description of new species, resulting in a current total of 28 species. In Argentina, 11 species have been identified; however, the validity of Saccocoelioides bacilliformis and Saccocoelioides octavus remains controversial. Recently, specimens of digeneans were collected from two distinct geographical locations: the Paraná River basin (Misiones province) and the Río de la Plata basin (Buenos Aires province). These specimens were found parasitizing two different fish species: Bryconamericus sylvicola and Bryconamericus iheringi. Sequences of the 28S and COI genes were obtained for both digeneans from the two collection sites and hosts. The morphological study, combined with genetic sequences, confirmed their assignment to the genus Saccocoelioides. The COI and 28S gene sequences obtained from specimens at both collection sites exhibited genetic distances of 0.13% and 3.41%, respectively, indicating that these Saccocoelioides specimens represent a single species. The comprehensive taxonomic study of the newly collected specimens, along with an examination of the type material of S. bacilliformis and S. octavus, allows us to confirm the validity of both species. Argentina is home to more than 550 species of freshwater fauna, and it is likely that new species of Saccocoelioides remain to be discovered in underexplored regions of the basin, such as the Uruguay, Pilcomayo and Bermejo rivers.

Previous studies have shown that helminth infection protects against the development of diabetes mellitus (DM), possibly related to the hygiene hypothesis. However, studies involving Stronglyoides stercoralis and its possible association with DM are scarce and have shown contradicting results, prompting us to perform this meta-analysis to obtain more precise estimates. Related studies were searched from PubMed, Google Scholar, Science Direct, and Cochrane Library until 1 August 2024. Data on the occurrence of DM in patients positive and negative for S. stercoralis were obtained. All analyses were done using Review Manager 5.4. The initial search yielded a total of 1725 studies, and after thorough screening and exclusion, only five articles involving 2106 participants (536 cases and 1570 controls) were included in the meta-analysis. Heterogeneity was assessed, and outlier studies were excluded using a funnel plot. Results showed a significant association of S. stercoralis infection with DM, suggesting that those with the infection are less likely to develop DM. Overall, the results suggest that S. stercoralis infection may decrease the likelihood of developing DM, potentially supporting the hygiene hypothesis.

Meteterakis striatura Oshmarin & Demshin, 1972 is redescribed from the posterior intestine of tropical tortoise Geoemyda spengleri (Gmelin, 1789) (Testudines: Geoemydidae) from China. Some characteristic features of the male reproductive system not reported previously are now reported for the present species. These include the presence of two blind diverticula near the mid-region of the seminal vesicle and a small cuticular structure near the opening of the cloaca – which we propose to name the ‘scutum.’ The morphological function and diagnostic value of these characters as well as presence of gubernaculum or ‘gubernacular mass’ in examined representatives of the genus, including paratype specimens of M. amamiensis Hasegawa, 1990 and M. ishikawanae Hasegawa, 1987 is discussed. Illustrative material is supplemented with scanning electron microscope and light microscope images of adult males and females. The molecular characterization of the species is inferred from 18S and 28S rDNA. The taxonomic composition of the genus Meteterakis is discussed and the full list of species with taxonomic remarks is updated.

Brine shrimps (Artemia spp.) are aquatic crustaceans known as important intermediate hosts for a wide range of helminth species. From 2011 to 2021, 4,347 individuals of brine shrimp were collected for this study, investigating the diversity and infection rates of helminth species in Artemia spp. from hypersaline waters in southern and eastern Ukraine. Seven helminth species were found: six cestodes (Anomotaenia tringae, Eurycestus avoceti, Branchiopodataenia gvozdevi, Confluaria podicipina, Fimbriarioides tadornae, Hymenolepis s.l. stellorae) and one unidentified acuariid nematode (Acuariidae gen. sp.). All these helminths were recorded for the first time in intermediate hosts in Ukraine, although they had been known from other regions. Additionally, partial sequences of the 18S rDNA gene as well as the mitochondrial cytochrome c oxidase subunit 1 (cox1) and nicotinamide adenine dinucleotide dehydrogenase subunit 1 (nad1) genes were obtained for varying numbers of cestode and nematode isolates for the first time. The overall prevalence of helminth infection in Artemia spp. was 21.9%, and the intensity ranged from one to three specimens.

A new species of Heligmostrongylus (Nematoda: Heligmonellidae) is described from the small rodents Ototylomys phyllotis (Cricetidae: Tylomyinae) and Heteromys gaumeri (Heteromyidae: Heteromyinae) in the Yucatan Peninsula, Mexico, based on studies of light and scanning electron microscopy, and partial sequences of COI, ITS1 and 28S rRNA. Heligmostrongylus yucatanensis n. sp. is characterized by a synlophe of 13 interrupted ridges (except those forming careen) in both sexes at midbody; males with a ventral cuticle inflation at anterior region of copulatory bursa, rays 9 and 10 long, comparable in length, and rays 9 strongly curved laterally at a right angle crossing ventrally rays 8; and females with a torsion of 180° to left of the posterior extremity. These characteristics were shared with Heligmostrongylus nematodes reported previously from O. phyllotis and Peromyscus yucatanicus (Cricetidae: Neotominae) also in the Yucatan Peninsula. The absence of intraspecific sequence variations in COI, and the low variation in D2-D3 expansion segments of 28S rRNA and ITS1 among the specimens obtained from the different hosts provided strong support that the worms found in the three rodent species belong to the same new species. The nine previously known species of Heligmostrongylus have been reported from caviomorph rodents of the families Cuniculidae, Dasyproctidae, Echimyidae, and Erethizontidae from the Neotropics. The occurrence of H. yucatanensis in three phylogenetically distant rodent species suggests that this nematode species could have the ability to expand its host range by colonizing new hosts.

Gastrointestinal tract (GIT) nematode infections have a significant negative impact on the well-being and productivity of animals. While it is common for a host to be co-infected with multiple species of nematode parasites simultaneously, there is a lack of effective tools to study the composition of these complex parasite communities. We describe the application of the “nemabiome” amplicon sequencing to study parasitic GIT nematode communities in captive wildlife at the National Zoological Garden, South African National Biodiversity Institute. A total of 13 samples from Roan antelope (n=1), Eland (n=1), Sable antelope (n=9), Arabian oryx (n=1), and Blue duiker (n=1) were analysed for the presence of GIT nematode infections. A total of 256 operational taxonomical units (OTUs) were generated and compared to a curated database with ≥99% identity to sequences in the NCBI database. The OTUs found represented nematode species which are commonly associated with wild ruminants. These belonged to members of the genera Haemonchus, Trichostrongylus, and Cooperia, with a few OTUs classified as unidentified genera detected. These were further classified to species level, with Haemonchus contortus and Trichostrongylus colubriformis having high relative abundance across all captive ungulate species. Utilizing amplicon sequencing to examine the nemabiome holds great potential for enhancing our basic knowledge of the biology of gastrointestinal nematodes and monitoring infections. This improved understanding could guide the development of more efficacious preventive and control measures against these significant parasites, which negatively impact animal health and productivity on a global scale.

Species of the family Echinostomatidae use diverse gastropod taxa as first intermediate hosts. However, identification of echinostomatid larvae often proves difficult because of incomplete information on their life cycles and lack of molecular data that can link larvae to the corresponding known adults. Here, echinostomatids that were isolated from freshwater limpets in South Africa were described using light and scanning electron microscopy, and ribosomal (28S, ITS, and 18S) and mitochondrial (cox1) DNA sequences. The analyses revealed three species: Petasiger radiatus, Petasiger sp., and Echinostomatidae gen. sp. Considering the close morphological resemblance between cercariae of Petasiger spp., the current species were compared with data from literature. The results showed that cercarial size is generally unsuitable for species discrimination. The numbers of flame cells and refractile granules in the excretory system, and penetration gland cell patterns, may indicate, but do not prove species identity. Although papillary patterns were distinct between species, papillae were clearly discernible only using scanning electron microscopy and are known for only a few species. Phylogenetic reconstruction indicated that 28S rDNA sequences of Petasiger on GenBank are for P. exaeretus, P. phalacrocoracis, P. radiatus, and six unnamed species. Furthermore, the results revealed that multiple ITS rDNA and cox1 sequences labelled as Stephanoprora amurensis and P. phalacrocoracis on GenBank, are from isolates whose identities are questionable. Echinostomatidae gen. sp. could not be assigned to any currently known genus. Expansion of the genetic database of the family Echinostomatidae is necessary for the delineation of putative species and elucidation of intergeneric relationships.

Trematodes are one of the most abundant and diverse groups of platyhelminths. They parasitize all major groups of vertebrates as definitive hosts and therefore play an important role in ecosystem composition. It is estimated that 18,000 to 25,000 species of trematodes exist worldwide, of which 685 have been reported in Mexico. Although this group is an integral part of ecosystems, there are still no studies that highlight the importance of parasites, especially in conservation approaches. Here, we recompiled information on the occurrence and available genetic data of trematodes in Mexico to estimate the specific richness of their representation across the Protected Areas (PAs) and provinces of Mexico. We consulted national and international databases (e.g., GBIF, CONABIO, CNHE-UNAM) and genetic repositories (e.g., GenBank) to generate curated datasets. We obtained 6,780 records that represent 99% of species reported in Mexico (680 species), of which only 10.2% are included in PAs. For genetic data, we found information from five nuclear regions (28S, 18S, ITS1, ITS2 and 5.8S) and two mitochondrial genes (COI and NAD1) for 118 species, of which only 3.5% were associated with PAs. With these results, we provide a spatial distribution of records (occurrence and genetic data) of trematodes present in Mexico and its PAs and identify poorly represented biogeographic provinces (e.g., Sierra Madre del Sur). We also highlight that this is the first study in Mexico to include this group in a conservation approach, and we record valuable information for future studies.

Fasciolosis, caused by the liver flukes Fasciola hepatica and Fasciola gigantica, is a zoonotic parasitic disease associated with substantial economic losses in livestock. The transforming growth factor-beta signalling pathway is implicated in developmental processes and biological functions throughout the animal kingdom, including the Fasciola spp. It may also mediate host–helminth interactions during infection. In this work, we present an exploration of FgSmad4, the sole member of the Co-Smad protein family in F. gigantica. The isolated FgSmad4 cDNA was 4,014 bp in length encoding for a protein comprising 771 amino acids. FgSmad4 exhibited typical Co-Smad protein features, including Mad Homology 1 (MH1) and Mad Homology 2 (MH2) domains, a Nuclear Localisation Signal, a DNA-Binding Motif, and a Nuclear Export Signal. Sequence and phylogenetic analyses of FgSmad4 revealed that its MH1 and MH2 sequences are most similar to those of other trematode species. The MH1 domain, in particular, closely resembles the Co-Smad protein in mammalian hosts more than those in cestodes and nematodes. The expression patterns of FgSmad4 during the liver fluke’s developmental stages showed significant variation. Transcript levels were highest at the newly excysted juvenile stage, followed by unembryonated egg, redia, and metacercaria, with the lowest expression in the adult fluke, embryonated egg, and cercaria stages. Our results underscore the conservation and suggest the potential role of FgSmad4, a key transforming growth factor-beta signalling molecule within the liver fluke F. gigantica. As Co-Smad is typically involved in several biological pathways, the precise functions and mechanisms of this identified FgSmad4 necessitate further exploration.

The genus Enenterum Linton, 1910 comprises species which parasitize herbivorous kyphosid fish. In the present study, a new species is described based on fresh specimens collected from Kyphosus incisor from Rio de Janeiro. The new species is characterized by having the oral sucker infundibuliform with 10 lobes, prepharynx two times longer than pharynx, presence of oesophagus, testes slightly lobed, round ovary and rectum with muscular sphincter connected to the anus. New genetic sequences include partial 18S and 28S rDNA and ITS1-5.8S-ITS2. The phylogenetic analyses place Enenterum gomesae n. sp. as sister of Enenterum aureum, corroborating the morphological analyses. Enenterum aureum (=E. pimelopteri) previously described from Kyphosus spp. from Rio de Janeiro is now considered E. gomesae n. sp. The new species represents the only South American species so far described for this genus.