An adult female great curassow (Crax rubra) and an adult female crested guan (Penelope purpurascens) were examined post-mortem and found to harbour trematode flukes in their pulmonary air sacs and coelom, with severe pathological changes. Seven trematode specimens (four from C. rubra and three from P. purpurascens) were stained with hydrochloric acid–carmine for optical microscopy, while four specimens (two from each bird species) were submitted to molecular analysis. Morphological and molecular analyses identified the specimens as Circumvitellatrema momota. Phylogenetic analysis showed that C. momota from different geographical origins constitutes a single species within the subfamily Cyclocoelinae and is clearly distinct from other cyclocoelid genera. This is the first documented case of C. momota infecting members of the Cracidae family. These findings highlight the importance of monitoring parasitic infections in captive and free-ranging cracids under conservation programmes.

The white mullet, Mugil curema (Mugilidae), is a catadromous euryhaline fish with an omnivorous diet, and is distributed mainly along the Pacific and Atlantic coasts of the Americas. Mullets represent an important economic resource for the artisanal fisheries in Mexico. In this study, 73 individuals of M. curema were analysed; specimens were sampled in 4 coastal lagoons of the Yucatán Peninsula, Mexico, between 2022 and 2024. Parasite identification was accomplished by using DNA sequences. Nineteen parasite taxa were found, including 1 monopisthocotylan, 1 copepod, 1 acanthocephalan, 1 nematode, and 15 trematodes. Specimens were sequenced for a nuclear or mitochondrial molecular marker. Ten taxa are reported for the first time in this host species, including the adult trematodes Saccocoelioides olmecae; Schikhobalotrema sp. 1 and sp. 2, Hemiuridae gen. sp., the larval trematodes Mesostephanus microbursa, M. cubaensis, Cardiocephaloides medioconiger, Saccularina sp., Bucephalus sp., as well as the larval nematode Contracaecum fagerholmi. Of the 21 metazoan parasites recorded, 58% were adults and 42% were larval stages. The checklist of the metazoan parasites of M. curema was updated. Our study contributes to the understanding of the parasite diversity of an economically important fish species with a wide distribution range and corroborates the usefulness of combining morphological and molecular data for species identification and for linking larval forms with adults to complete parasite life cycles. Our results will be useful in further studies of parasites as bioindicators of ecosystem health, and studies of the role of parasites in food webs in coastal lagoons.

TEM analyses of germinal elements in miracidia and 6-day-old mother sporocysts of Echinostoma caproni were performed. Germinal elements in miracidia are represented by undifferentiated cells and germinal cells. They are localised in the posterior half of the body and form the primordium of the germinal mass, which plays the role of the gonad. In mother sporocysts the germinal mass is located caudally and plays the dual role of the gonad and the uterus. In addition to the undifferentiated cells and germinal cells, it contains embryos, which develop there up to the stage of germinal balls and then move into the sporocyst’s schizocoel, which plays the role of the brood chamber. New germinal cells are formed only by division of undifferentiated cells. No differences between undifferentiated and germinal cells in miracidia and those in sporocysts were found.

Amerotyphlops brongersmianus (Vanzolini, 1976) is the only representative of its family in Argentina, and to date, there have been no records of its parasites. Between 2013 and 2018, 46 specimens of A. brongersmianus were collected in Corrientes province and investigated for helminths. Eighty-three specimens of Serpentirhabdias aff. vellardi were collected from the lungs of nineteen hosts. Sixty-nine percent of the nematodes were collected from the vascular lung mostly, with a prevalence of 41.3% and a mean intensity of 3.74 worms. Adult snakes had higher prevalence and mean abundance than juveniles; the mean intensity was similar between sexes and sexual maturity groups. The association between sexual maturity and the presence of lungworms was statistically significant. Lungworm abundance, weight, and length of adult snakes showed weak to strong positive correlations, with stronger correlations in males; however, these were not statistically significant. Nematodes followed a negative binomial distribution. Seasonal differences in parasitological descriptors and mean body length of lungworms were not statistically significant. Nonetheless, a significant negative correlation was observed between lungworm abundance and body length in spring, suggesting a clustering effect. Our results are discussed based on host phenology, ecology, biology, and anatomy. The life cycles of lungworms, the abundance of potential transport hosts, as well as abiotic factors (rainfall and temperature), are also considered. This is the first report of lungworms in A. brongersmianus throughout its range, the second global report of helminths in a Typhlopidae species in the 21st century, and the first in South America and Argentina, providing ecological data.

The genus Alloophistolecithum was recently created and comprises species that were previously included in the genus Lecithaster. The two genera form the subfamily Lecithasterinae. The genera includes species that predominantly parasitize marine fish, and occasionally those inhabiting fresh or brackish water. This study describes a new species of Alloophistolecithum, which is a parasite of the Argentinian silverside (Odontesthes bonariensis), a fish species that inhabits brackish waters. Alloophistolecithum magaliae n. sp. is characterized by smooth, unnotched testes; a uterus extending to the posterior end of the body; and short caeca that do not reach the anterior edge of the vitellary. As genetic analyses are currently limited to a few species within the genus, it is premature to establish clear relationships between them. The Argentinian silverside is considered to be of great economic importance, having spread not only within Argentina but also to other countries for commercial exploitation. The anthropogenic spread of silversides outside their natural range could pose a risk of biological invasion, so studying their parasitological fauna is important.

Trichostrongylus spp. are globally distributed gastrointestinal nematodes that affect ruminants and humans, posing significant veterinary and public health challenges. Despite their zoonotic potential, the temporal dynamics of Trichostrongylus infection remain poorly understood globally. This study aimed to estimate long-term trends in Trichostrongylus prevalence in humans, ovines, and bovines using time series modelling. A systematic review identified 240 eligible studies with annual prevalence data across 60 countries. Following Kalman smoothing, annual prevalence time series were constructed for each host species covering 1947–2024 for humans, 1966–2024 for ovines, and 1962–2024 for bovines. ARIMA models were fitted separately: ARIMA(0,1,1) for humans, ARIMA(3,0,0) for ovines, and ARIMA(0,1,1) for bovines. Model selection was based on Stationary R2, RMSE, MAPE, and the Ljung-Box Q test for residual independence. Forecast 95% confidence intervals were reported to convey uncertainty in the projected trends. All three models demonstrated good in-sample fit and adequate residual diagnostics. Infection rates in humans and bovines are projected to decline, from 4.64% to 3.73% in humans and from 20.11% to 11.76% in bovines by 2034. In contrast, the ovine model forecasts an increase in infection rates, from 6.50% to 15.56%. This increase in ovines may reflect greater pasture exposure and environmental persistence of infective larvae, while improvements in hygiene and livestock management likely contribute to the declining trends observed in humans and bovines. The rising infection rate in ovines, coupled with sustained zoonotic risk, underscores the need for integrated One Health surveillance and control efforts.

Avian schistosomatids are blood flukes parasitizing a wide spectrum of aquatic birds. However, its research in the Neotropics is ongoing with several putative new taxa pending description. Although waterfowl represent the most important avian hosts for these flukes, only a small proportion of these birds have been assessed for schistosomatids. This study aimed to describe avian schistosomatids from two native ducks from the Southern Cone of South America. A total of 24 Chiloe wigeon (Mareca sibilatrix) and three Cinnamon teals (Spatula cyanoptera) from different localities in Chile and Argentina were dissected to retrieve schistosomatids. The retrieved worms were described through an integrative approach considering morphology (staining and SEM) and molecular tools (PCR: COI, 28S rRNA genes). The new schistosomatid: Trichobilharzia kulfu sp. nov. was recovered from the viscera of Chiloe wigeon. It was closely related to other undescribed Trichobilharzia taxa from the United States, also from Mareca ducks. The new species was morphologically and molecularly different from other Trichobilharzia species, and it was included in the clade Q. In addition, SEM imaging proved to be an important tool to describe unnoticed traits on the tegument of worms. This new species represents the second Trichobilharzia taxon from the Neotropics described through an integrative approach. Furthermore, the Cinnamon teals harboured Trichobilharzia querquedulae. Considering there are several avian schistosomatids described only through morphological or molecular tools, there is a clear need to include a comprehensive approach in the description of avian schistosomatids, considering the remarkable richness of schistosomatids in Neotropics.

This study examined the metacercariae of trematodes in cnidarian jellyfish around Japan to demonstrate the importance of the jellyfish as the second intermediate or paratenic hosts. Trematodes were sampled from cnidarian jellyfish in seven coastal regions of Japan between 2024 and 2025. Trematodes (adults and metacercariae) were also obtained from marine fish and arrow worms and included for data comparisons. DNA barcoding was used for the species identification of metacercariae in the jellyfish and for elucidating their partial life cycles. Eight cnidarian species (245 individuals) were sampled, with metacercarial infection detected in seven host species. Based on morphological and molecular analyses, the metacercariae were classified into nine species belonging to three families, Accacoeliidae, Hemiuridae, and Lepocreadiidae. Six of these species were identified as the same species of adults isolated from fish hosts around Japan, although species names of two of the six remained unclear. The remaining three trematode species were assumed to belong to Lepocreadiidae, a major group of fish trematodes. These findings indicate that cnidarian jellyfish are important intermediate or paratenic hosts of fish trematodes in Japanese waters, as has been reported in other areas in previous studies. Moreover, a metacercaria occasionally detected in an arrow worm was identified as the same species as those in jellyfish, suggesting predator–prey relationships between these hosts. The study also synonymised Tetrochetus hamadai Fukui and Ogata, 1935, T. aluterae (Hanson, 1955), and T. mitenevi Zubchenko, 1978, with T. coryphaenae Yamaguti, 1934, based on molecular and morphological data.

Cylicospirura is a genus of spirocercid nematodes infecting felids around the globe. Eleven species have been characterised, with C. felineus and C. subaequalis being reported in jaguarundis, Herpailurus yagouaroundi, from Brazil. Herein, we described spirocercid reddish worms collected from three jaguarundis from Costa Rica by using hierarchical clustering and dendrogram plots of morphological characters reported from our specimens and compared to other Cylicospirura spp., histopathological observations of associated lesions, and phylogenetic analyses of both mitochondrial and ribosomal loci. Nematodes were found within stomach nodules located in the submucosa causing a pyogranulomatous, multifocal, nodular, and sclerosing gastritis. In addition, the collected worms differed from their congeners by having a longer body and smaller muscular and glandular oesophagus, subsequently showing lower total oesophagus to body length percentage and ratio of glandular to muscular oesophagus. Cytochrome oxidase subunit 1 and internal transcribed spacer 1 analyses revealed that worms were 8.33 to 8.66% different from C. felineus, C. subaequalis, or C. petrowi and 15.2 to 15.4% different from C. petrowi, respectively. Moreover, sequences derived from collected worms clustered separately from other Cylicospirura spp. available in GenBank® in the phylogenetic trees. By using an integrative taxonomy approach, the nematodes collected from stomach nodules of jaguarundis were described as a new taxon, for which the name Cylicospirura wishkai sp. nov. is proposed.

China accounts for over 90% of global alveolar echinococcosis (AE) cases caused primarily by Echinococcus multilocularis. If left untreated, AE can have a 10-year mortality rate of 94%. Understanding its epidemiological patterns is essential for targeted control strategies. Surveillance data from 2006 to 2020 were obtained from the Public Health Scientific Data Center, and spatial and temporal trends were analyzed using spatial autocorrelation, hot spot analysis, and centroid migration techniques. A total of 51,403 echinococcosis cases were reported from 2006 to 2020, with an average annual incidence of 0.25 per 100,000. Most cases (71.33%) occurred in individuals aged 20–60 years. High-incidence areas centred in western/northwestern provinces, including Qinghai, Xinjiang, Xizang, Gansu, and Ningxia. Incidence and cases increased until 2017, then declined steadily. Spatial autocorrelation revealed persistent High-High clusters in Gansu and Ningxia (2008–2018) and Xizang (2010–2020), while Low-Low clusters persisted in central/eastern China. Hotspot analysis confirmed sustained high-risk zones in western/northwestern regions. Trend surface and centroid migration showed a southward disease shift within Qinghai. Echinococcosis remains endemic in western/northwestern China, with a trend of southward expansion. Strengthened, tailored interventions are urgently needed, particularly in high-burden areas like Xizang and Qinghai.

Based on morphological and molecular data, we describe a new species of Diaphorocleidus parasitizing the nasal cavities of Tetragonopterus argenteus from the Lima Campos weir, municipality of Icó, state of Ceará, Brazil. Diaphorocleidus radius n. sp. resembles other congeners in the morphology of the accessory piece, all by having a bifurcated accessory piece (pincer-shaped), composed of two subunits articulated. However, the new species can be easily distinguished from all congeners by the morphology of the sclerotized structures of the haptor (ventral anchor with well-developed superficial root, ornamented deep root, recurved blade, elongated and lightning-shaped tip; and ventral bar robust, plate-shaped, truncated in lateral ends). Phylogenetic analyses of LSU rDNA and COI mtDNA sequences, conducted using Bayesian Inference and Maximum Likelihood, placed Diaphorocleidus radius n. sp. within Diaphorocleidus, grouping it with species parasitizing acestrorhamphid hosts. Genetic distances between Diaphorocleidus radius n. sp. and other congeneric species such as D. armillatus and D. forficata showed clear differentiation. Both molecular markers support the distinctiveness of Diaphorocleidus radius n. sp., consistent with its recognition as a new taxon.

Preserving viable infective stages of chicken ascarids under laboratory conditions facilitates the maintenance of characterized nematode strains for research purposes. We investigated the survivability of Ascaridia galli eggs exposed to low temperatures and the cryoprotectant dimethyl sulfoxide (DMSO). Two egg developmental stages (unembryonated or fully embryonated) were stored at 4°C, –20°, or –80°C in sterile water or with 5% and 10% DMSO for 1, 2, 4, or 8 weeks. Egg survival was assessed by morphology following post-storage incubation in 0.1 N H2SO4 at 26°C for unembryonated eggs or with a viability dye exclusion test of hatched larvae for the embryonated eggs. The results revealed that neither DMSO nor the hardy chitinous eggshell protected eggs from freezing damage, and not a single egg survived even for 1 week of storage at –20° or –80°C. DMSO at 10% significantly reduced (P < 0.0001) overall egg survival and embryonation capacity with increasing storage time at 4°C compared to water alone. For both egg developmental stages, egg survival was maintained in 5% DMSO at a rate similar to that in water alone. Unembryonated A. galli eggs survived refrigeration better than embryonated eggs with larval viability declining linearly at almost a double rate in the latter (9.75%/week) compared to the former (5.64 %/week). We conclude that DMSO is unlikely to provide cryoprotection for A. galli eggs and also causes concentration-dependent toxicity with increasing exposure time. Furthermore, survival during refrigeration is better for unembryonated than embryonated eggs.

Here we report microfossil helminth analysis of soils/sediments from the Cloudman site, Lake Huron, Michigan, encompassing the Early Late Woodland (AD 500/600–1000) to the early Historic period. Results reveal eggs of the dog nematode Toxocara canis (a first for North America), the human nematode Ascaris lumbricoides, and a species of taeniid cestode, intestinal parasites that could have affected the health of people and their domesticated dogs. The eggs suggest that the presence of dogs at the site remained relatively stable over the c. 1000-year span of this period. The results offer a new line of evidence for possible dog presence and domestication in North America.

Exposure to certain parasites can occur when hosts encounter clumps of infective larvae during ingestion. Compared to more typical transmission pathways involving the cumulative penetration or ingestion of single larvae, clumped transmission can be expected to lead to complex and variable epidemiological patterns of infection within exposed hosts. We explored this idea in a spatiotemporal survey of wood ants (Formica spp.) infected with metacercariae of the host-manipulating trematode, Dicrocoelium dendriticum. Ant second intermediate hosts are exposed to clumps of cercariae during ingestion of ‘slimeballs’ that are released onto pasture by land snail first intermediate hosts. In a total sample of >650 ants collected during the host-manipulation phase when ants were attached to plants, metacercariae prevalence was 97% and mean intensity was 27 ± 25 (range in intensity = 1–168; variance:mean ratio = 23.1). None of the observed variation in mean metacercariae intensity could be attributed to year (2021, 2022), month (May to August), or nest. Although the recruitment of metacercariae into ants occurred within a narrow window of transmission each summer, the mixed-age structure of our ant samples likely limited our ability to detect seasonal patterns of mean intensity. The absence of significant spatiotemporal patterns in metacercariae intensity in samples of ants likely also reflects infrequent and variable rates of encounter with cercariae-containing slimeballs by individual ants.

Anisakis pegreffii (Nematoda: Anisakidae) is a marine parasitic nematode responsible for anisakiasis, a zoonotic disease acquired through the consumption of raw or undercooked fish. With the rising popularity of dishes such as sushi and sashimi, the risk of infection has grown, prompting the need for effective food-safety measures. This study investigates the nematocidal effects of commercial wasabi substitute paste (WSP) and its bioactive compound, allyl isothiocyanate (AITC), on third-stage larvae (L3) of A. pegreffii, and explores their associated stress-response mechanisms. WSP at 1 g/mL and 2 g/mL significantly reduced larval viability, with hazard rates of 3.1% and 3.8% per minute and mean lethal times of 45 and 30 minutes, respectively (p < 0.0001). AITC, tested at a 10-fold dilution, exhibited stronger activity, inducing 50% mortality in 16 minutes with a hazard rate of 13.45%/min. Expression analyses revealed that WSP robustly upregulated HSP70 mRNA and protein in a time-dependent manner, whereas AITC caused only a modest increase in HSP70 mRNA without a significant protein-level rise over the same exposure window. Conversely, HSP90 expression showed early, transient upregulation followed by suppression or downregulation, suggesting differential regulation of heat shock pathways under chemical stress. These findings demonstrate that WSP and AITC exert potent, rapid nematocidal effects on A. pegreffii larvae and elicit distinctive molecular stress responses. The data support the potential of wasabi-derived compounds as safe, natural agents for reducing anisakiasis risk in raw seafood consumption.

We report a nearly complete mitochondrial genome (mitogenome) of Echinostoma caproni (Egyptian isolate), which was reassembled and thoroughly annotated from whole-genome sequencing data available from Sequence Read Archive (accession No. ERS055227). Although a mitogenome of E. caproni has previously been deposited in GenBank (accession No. AP017706), it represents a partial sequence lacking the transfer RNA (tRNA)-Ser2 and possessing only a short non-coding region. In contrast, the newly reconstructed mitogenome in this study is 14,549 bp in length and comprises 12 protein-coding genes, 22 tRNA genes, 2 ribosomal RNA genes, and a 1,256 bp non-coding region containing 4 repeat units. The annotated sequence has been deposited in the Third Party Annotation database in GenBank (accession No. BK071757). Phylogenetic inference based on mitogenomic data indicates that E. caproni is closely related to E. miyagawai strains. This improved mitogenome provides a reliable genomic resource for comparative mitogenomic analyses and phylogenetic studies within the family Echinostomatidae.

Strongyloides stercoralis infection affects approximately 600 million individuals worldwide. This parasite has the ability to exacerbate infection through internal autoinfection, which can lead to hyperinfection and/or dissemination, conditions associated with high morbidity and mortality, particularly in immunocompromised patients such as those with alcohol use disorder (AUD). In this study, we conducted a meta-analysis to assess the prevalence and risk of having S. stercoralis infection among individuals with AUD. Searches were performed in the PubMed, Embase, and LILACS databases to identify studies investigating the prevalence of S. stercoralis infection in individuals with AUD, with or without comparison to non-alcoholic groups. The pooled prevalence was calculated using the Probit Logit (PLOGIT) transformation, and the odds ratio (OR) was used for risk comparison. The initial search yielded 154 studies, of which seven were included in the systematic review and meta-analysis. The combined prevalence of S. stercoralis infection among patients with AUD was 16.9%. Risk analysis based on four studies showed that individuals with AUD had a 6.08-fold higher risk of infection compared with non-alcoholic individuals. These findings highlight chronic alcoholism as a significant risk factor for strongyloidiasis, likely due to a combination of environmental, physiological, and immunological factors. This meta-analysis underscores the critical need for routine screening for S. stercoralis infection in patients with AUD, even in the absence of clinical symptoms, to ensure early detection and timely intervention.

A ParasiteBlitz event offers a brief, intense opportunity to discover diverse parasite species and to reveal life cycles of heteroxenous parasite taxa. In this study, we describe Monomyxum ligophori n. sp., a hyperparasitic myxozoan (Monomyxidae) proliferating in two dactylogyrid monopisthocotylan flatworms (Ligophorus saladensis, Ligophorus mugilinus) infecting mugilid fishes (Mugil cephalus, Mugil curema) on the Atlantic coast of North America. Furthermore, we used DNA barcoding to infer the parasite’s complex life cycle, matching its hyperparasitic myxospore stages with actinospore stages infecting the polychaete Streblospio benedicti found in the same locality during the ParasiteBlitz and also reported previously from the same region. Thus we report the first life cycle of a myxozoan that most likely does not require a vertebrate host. Hyperparasitic myxozoans are rare with only five species reported worldwide to infect flatworms. This study provides more information on the previously discussed host specificity towards monopisthocotylan hosts of these monomyxid myxozoan hyperparasites. Notably, Monomyxum ligophori n. sp. was detected in two out of four gill-infecting parasitic flatworms (being absent in Ligophorus uruguayensis and Metamicrocotyla macracantha) found infecting the same fish individuals during the ParasiteBlitz. Our molecular data and phylogenetic analysis support the previously suggested common origin of Monomyxum species infecting monopisthocotylan flatworms, and contribute to understanding the life cycle and host interactions of this unique hyperparasitic myxozoan lineage.