Bees are key species for pollination and apiculture. Within the multiple biotic threats, parasites are one of the main players involved in bee health. Among them, trypanosomatid parasites have been the focus of recent studies that have placed them as one of the most prevalent microorganisms in the digestive tract of bees around the world. Here, we review what is known in epidemiology, cell biology and genetics of these parasites in bees with a particular focus on the work made on honeybees. We also discuss the possible implications for honeybee health and describe research gaps to be explored both from the honeybee host and trypanosomatid parasites sides.

We examined the frequency distributions of worm burdens and worm biomass of the dominant gastric nematode, Protospirura muricola, of eastern spiny mice (Acomys dimidiatus) surveyed at 4-year intervals over a period of 12 years in two montane wadis in St. Kathrine's Protectorate in S. Sinai, Egypt. Whilst the frequency distribution of worm burdens differed significantly between the mice from the 2 wadis, variation between years was not significant among mice from each wadi. The frequency distribution of P. muricola worm burdens did not differ significantly between the sexes, despite female mice carrying significantly higher worm burdens, but showed a marked difference between juvenile and mature mice. The biomass of P. muricola carried by individual mice varied considerably, with two mice from Wadi Gharaba carrying biomasses of over 1 gm, representing over 2.5% of total body weight. Biomass showed significant positive covariation with worm burdens, and heavy biomass and worm burdens were most likely among the older mature female mice. The frequency distribution of individual worm weights indicated that frequent low-dose transmission was common, with rarer instances of higher-dose, package transmission from insect vectors of this parasite.

South American ecosystems harbour diverse cricetid rodents and their associated nematode parasites, with implications for ecology and zoonotic risk. We conducted a systematic review following the PRISMA guidelines to catalogue nematode taxa reported from the digestive tract and accessory organs of cricetid rodents in Argentina and Chile. Searches were carried out in five databases (PubMed, WoS, Scopus, SciELO, and Google Scholar) up to 10 January 2026. Parasitological descriptors, such as prevalence (P), mean abundance (MA), and mean intensity (MI) were estimated. We analysed 53 studies examining 4400 rodents (33 species), with Abrothrix olivacea (n = 1000 specimens) and Akodon azarae (n = 775 specimens) most frequently sampled. Ninety-two nematode taxa were reported, with A. olivacea exhibiting the highest richness (17 taxa). Guerrerostrongylus zeta showed the highest P (97.56% in Oligoryzomys nigripes), followed by Stilestrongylus stilesi (92.5% in Necromys lasiurus) Peak infection intensities occurred with Stilestrongylus flavescens in O. flavescens (MA = 72.79/MI = 126.7) and St. stilesi in N. lasiurus (MA = 120/MI = 129.73). This review provides the first comprehensive synthesis of gastrointestinal and hepatopancreatic nematodes in cricetid rodents from Argentina and Chile, highlighting research biases and priorities for advancing our understanding of nematode–cricetid rodent dynamics in the region. The overrepresentation of A. olivacea underscores the need to expand the range of cricetid rodent sampled and to increase the use of non-invasive and molecular diagnostic tools. Addressing these gaps will improve our understanding of nematode diversity and associated zoonotic risks in cricetid rodents in these countries.

The genus Apharyngostrigea comprises a group of diplostomoidean digeneans that parasitize birds of the family Ardeidae (herons), with approximately 20 species described worldwide. Despite numerous efforts, a robust phylogenetic framework to delimit species within the genus is still lacking, mainly due to the limited morphological variation among its members. This study employed an integrative taxonomic approach, combining nuclear and mitochondrial DNA sequences with morphological data to assess species boundaries within Apharyngostrigea based on specimens collected from southeastern Mexico. Using a combination of species discovery (Automatic Barcode Gap Discovery, Assemble Species by Automatic Partition, General Mixed Yule Coalescent and Poisson Tree Processes) and validation methods based on Bayesian gene tree topologies (BPP and PHRAPL). We found high diversity within this genus in southeastern Mexico. Our analyses supported the delimitation of four nominal species that were previously described and validated in this study, along with the redescription of three of them. In addition, through species delimitation methods and morphological examination, we identified two candidate species and/or lineages that require further evidence to be formally described. This study demonstrates that an integrative taxonomic approach provides a robust framework for species delimitation in taxonomically complex groups such as Apharyngostrigea.

An extensive survey of North American catostomid fishes yielded insights into the diversity, host specificity and phylogenetic relationships of monopisthocotylans belonging to Pseudomurraytrematidae. Parasites were recorded from 14 of 16 host species surveyed. In total, 22 species of Anonchohaptor, Icelanonchohaptor and Pseudomurraytrema were collected, including 7 new species. Most species were recovered from gills, whereas two Icelanonchohaptor species were found on fins. Phylogenetic analyses based on 28S rDNA support the monophyly of Pseudomurraytrematidae and its sister relationship to Diplectanidae. Within the family, Pseudomurraytrema asiaticum – a parasite of the East Asian fish Myxocyprinus asiaticus – was recovered as sister to the clade of Nearctic pseudomurraytrematids, a placement that may reflect geographic and host-associated separation. The remaining Pseudomurraytrema species parasitize North American Catostominae and form a well-supported clade sister to the clade comprising species of Anonchohaptor and Icelanonchohaptor, primarily associated with Ictiobinae. Under this topology, Pseudomurraytrema, as currently circumscribed, may be paraphyletic. Relationships between morphologically similar species of Anonchohaptor and Icelanonchohaptor remain unresolved: in the 28S tree, Anonchohaptor is paraphyletic (with Icelanonchohaptor nested within it), whereas the concatenated 18S–ITS1–28S analyses recover a single clade with Icelanonchohaptor (2 spp.) sister to the remaining species of Anonchohaptor. The parasite phylogeny broadly reflects host relationships, though several incongruences point to historical host switching. Morphological data also support the monophyly of Pseudomurraytrematidae via a synapomorphic male copulatory organ (U-shaped copulatory tube with a submedial spine, 3-ramus accessory piece), indicating structural conservatism within this family.

Inverse surveillance seeks to identify potential pathogens before diseases emerge in populations. In this study, we conducted a molecular survey of eukaryotic vector-borne pathogens (VBPs) within ectoparasite species to anticipate disease outbreaks in animals and humans. We analysed fleas, lice, mites, ticks and triatomines collected from rodents, birds, carnivores and from the environment across Chile. After extracting genomic DNA, we employed an 18S rRNA gene amplicon-based sequencing strategy using Oxford Nanopore Technologies to characterize eukaryotic VBPs. Our findings revealed a narrow taxonomic range of microorganisms, with Hepatozoon as a well-supported taxon. A single sequence matching the genus Babesia was additionally confirmed via BLAST. The bioinformatic pipeline allowed the recovery of high-quality Hepatozoon consensus sequences, enabling robust phylogenetic and population genetic analyses and providing the first molecular record of Hepatozoon in triatomines and the first genetic detection of this parasite genus in trombiculid and macronyssid mites in the Americas. Three different Hepatozoon lineages were detected, which clustered with others found in rodents and reptiles. Analyses of molecular variance indicate that host identity may play a more influential role than geographic region in shaping the genetic differentiation of Hepatozoon lineages in Chile. Our study provides new data on ectoparasite–host–parasite associations, demonstrating the utility of nanopore metabarcoding data for exploring VBPs’ diversity, thereby expanding the known arthropod associations of the Hepatozoon genus and suggesting the role of these ectoparasites as its potential vectors. As some Hepatozoon species can cause animal disease, these findings constitute an early warning for veterinarians.

Global warming is widely recognized as a key driver of current and future changes in marine ecosystems. Parasitic trematodes are highly sensitive to temperature changes, which can lead to drastic impacts on surrounding communities. Copiatestes spp. (Family Syncoelidae) are relatively little-known trematodes with atypical life cycles that have been associated with a mass mortality event of seabirds in the Chatham Islands. As they forage at sea, seabirds get their legs tangled with the sticky, free-living infective stages of Copiatestes, which impairs their ability to take off and land. We tested the impact of seasonally fluctuating sea temperature on the dynamics of Copiatestes thyrsitae at various life stages (infecting second-intermediate host, Nyctiphanes australis euphausiid, and the third free-living infective stage in the water column) by sampling plankton biweekly for 12 months in Otago Harbour, New Zealand. We reveal that higher temperatures are significantly correlated with increases in prevalence and abundance of Copiatestes infections in euphausiids, with a rapid response observed within days to weeks following temperature increases. No correlation was observed between temperature and abundance of free-living stages. Infected euphausiids were smaller in size compared to uninfected individuals. The higher infection levels in euphausiids following warmer temperatures suggest a heightened risk of entanglement for coastal seabirds at these times. Smaller-bodied, surface-feeding seabird species that consume euphausiids are particularly at risk of entanglement. Our findings suggest that even short-term heatwaves can lead to higher risk of seabirds being entangled with Copiatestes filaments, with potentially dire ecological consequences during mass parasite releases.

Cystic echinococcosis (CE) is a zoonotic disease of high public health and economic importance. The disease is caused by various tapeworm species belonging to the Echinococcus granulosus sensu lato species complex. Among these, E. granulosus sensu stricto (genotypes G1 and G3) is the most common cause of human CE worldwide. The aim of this study was to analyse the genetic diversity and phylogenetic relationships of G1 and G3 isolates from Armenia and Türkiye, where CE has long been recognized as a significant public health concern. A large portion of the mitochondrial genome (11 675 bp) was sequenced for 85 parasite samples: 47 from Türkiye and 38 from Armenia. Samples originated from humans, sheep and cattle. For a global phylogenetic analysis, sequences from previous studies were included, yielding 280 G1 sequences and 55 G3 sequences from various host species and countries worldwide. The main results of this work revealed (i) high genetic diversity of G1 in Armenia and Türkiye; (ii) high genetic diversity of G3 in Armenia, whereas only a few representatives of G3 were detected in Türkiye; (iii) the subdivision of isolates of G1 and G3 from Armenia and Türkiye into several haplogroups; (iv) the dispersion of G1 and G3 haplotypes from Armenia and Türkiye across different haplogroups in global phylogenetic networks; and (v) the diffusion routes of G3 isolates from Türkiye to Armenia, from Iran to Armenia and from Iran to Greece. These findings highlight the importance of mitogenome analysis for monitoring the spread of CE among animals and humans.

The genus Oochoristica Lühe, 1898 (Cyclophyllidea: Linstowiidae) primarily parasitizes reptiles. A new species of Oochoristica was collected from the small intestine of Eremias roborowskii (Bedriaga, 1906), from the Turpan Basin of the Xinjiang Uygur Autonomous Region, China. Following hematoxylin staining, through microscopic examination and detailed morphological description, a comparative morphometric analysis was conducted against closely related congeners, with particular emphasis on key taxonomic indicators, including the reproductive system and cephalic structures. Phylogenetic relationships were inferred using a multilocus analysis based on the 18S rRNA, ITS1-5.8S-ITS2 and COI gene regions. Genetic distances were calculated to support species delimitation. The parasite exhibits the following diagnostic features: proglottids significantly wider than long; a scolex lacking a rostellum and hooks; 20–25 spherical testes clustered in the posterior region of the proglottid; genital pores irregularly alternating along the lateral margins; a bilobed, highly branched ovary; and an elliptical vitellarium situated anterior to the ovary. Phylogenetic trees demonstrated that the new species formed a distinct, well-supported clade with lower intraspecific genetic variation than interspecific divergence, thereby supporting its status as an independent species. This new species is the 19th Oochoristica taxon recorded in the Palaearctic realm and the first novel cestode found in Eremias roborowskii. In the present study, an integrative taxonomic approach was employed, which combined comparative morphology with molecular phylogenetics and zoogeographic analyses, thereby elucidating the phylogenetic significance of this species within the genus Oochoristica.

Trypanosoma (Megatrypanum) pestanai is a parasite of the Eurasian badger (Meles meles), reported in various European countries. However, its presence in the Iberian Peninsula had not been previously investigated. To address this knowledge gap and to assess its occurrence and potential risk factors associated with infection, we analyzed DNA from the spleens of 145 badgers sampled across 4 autonomous regions in northern Spain. Two real-time PCR assays using a reference 18S rRNA partial sequence of T. pestanai (92 bp) were developed: one based on SYBR Green chemistry and the other employing a TaqMan probe. Both protocols demonstrated excellent concordance. Defining a sample as positive when at least 1 assay yielded a positive result, the overall prevalence was 35%, consistent with values previously reported in other European populations. A logistic regression model indicated a significantly higher occurrence in badgers from the Eurosiberian bioregion (42%) compared to those from the Mediterranean bioregion (19%). No significant associations were found with age or sex. A subset of positive samples was further analyzed by conventional PCR targeting approximately 900 bp of the 18S rRNA gene and sequenced. All 9 high-quality sequences shared 99.75–100% identity with known T. pestanai sequences. These findings confirm that T. pestanai is a common parasite of Iberian badgers and suggest that more humid climatic conditions may favour its persistence, potentially through effects on host ecology or vector dynamics.

Egg hatching is a critical stage in the life cycle of parasitic nematodes and is strongly influenced by abiotic factors. This study investigates, under in vitro condition, the effects of temperature (5 °C, 10 °C, 20 °C, 30 °C) and salinity (0–70 psu) on egg hatching success in the two sibling species Contracaecum rudolphii sp. A and C. rudolphii sp. B, which have been hypothesized to be adapted to brackish/marine and freshwater environments, respectively. Hatching was completely inhibited at 5 °C in both species. At temperature of 10 °C and above, both taxa showed successful hatching with largely overlapping thermal profiles; however, C. rudolphii sp. A achieved a marginally significantly higher success, with maximum hatching observed at 30 °C – a value chosen to simulate a potential heatwave scenario. Temperature also influenced developmental timing, with faster hatching occurring at higher temperatures. In contrast, significant marked differences were observed along the salinity gradient: C. rudolphii sp. A hatched across a wide range (0–70 psu); while C. rudolphii sp. B was restricted to 0–20 psu, with a steep decline above 10 psu. The observed species-specific hatching dynamics, primarily driven by salinity factor, support differential ecological adaptation of the two taxa in their respective aquatic habitats. These findings also provide a basis for predicting parasite responses to environmental change, including rising temperatures and salinity shifts in aquatic ecosystems.

The Liolopidae Dollfus, 1934 is a small family of digenetic trematodes with sexual adults parasitic in aquatic reptiles and amphibians. Liolopids exploiting snakes are constrained to Harmotrema Nicoll, 1914, but the genus includes species with presumably freshwater life cycles parasitic in terrestrial snakes as well as species with presumably marine life cycles parasitic in viviparous sea snakes and amphibious kraits. We hypothesize that this ecological distinction implies substantial separation in evolutionary history and propose Sagaratrema De Silva, Pathirana & Martin n. g. to accommodate the liolopids in marine snakes. Three species are delineated through an integrated approach, from novel collections of viviparous sea snakes in Sri Lanka, Sagaratrema rajapaksei De Silva, Pathirana & Martin n. sp., Sagaratrema rajakarunae De Silva, Pathirana & Martin n. sp. and Sagaratrema indicum (Chattapadhyaya, 1970) n. comb. (= H. indica) originally reported from India. Three other species known from marine snakes are transferred from Harmotrema to the new genus: S. laticaudae (Yamaguti, 1933) n. comb. (designated as the type-species), S. eugari (Tubangui & Masilungan, 1936) n. comb. and S. linguiforme (Wang, 1987) n. comb. (= H. linguiforme). The 3 species from Sri Lanka are similarly genetically distinct in sympatry as each is relative to S. laticaudae from Japan. Following these proposals, Harmotrema is revised and rendered monotypic for the type-species H. infecundum. Morphologically, Sagaratrema is distinguished from Harmotrema and other liolopid genera by the arrangement of the excretory vesicles, distribution of the vitellarium and size and shape of the body.

Capillaria Moravec, 1987, is a genus of thin, threadlike roundworms infecting various hosts, including fishes. Fifteen species have been described from freshwater, brackish-water and marine fishes, primarily based on morphological characters. However, species identification remains challenging, and no molecular information is currently available for previously described Capillaria species. Utilizing morphological, scanning electron microscopy, and molecular evidence, we describe Capillaria (Procapillaria) nubthaiensis Chan, 2025 as a new species of capillariid infecting the commercially important fish Scomberomorus commerson from the Gulf of Thailand. Examination of 30 male and 30 female specimens revealed key morphological features distinguishing Capillaria nubthaiensis sp. nov. from other members of Capillaria (Procapillaria). These morphological characters include a unique female vulva that appears slightly protruding and forms a ‘knob-like’ shape appendage and a small papilla near the base of each male lobe with another pair of small papillae near the anus. Molecular phylogenies obtained from the nuclear 18S ribosomal RNA and the mitochondrial cytochrome c oxidase subunit I genes also support the distinction from other species in the family Capillariidae. The discovery of C. nubthaiensis sp. nov. represents the first record of a Capillaria species infecting S. commerson, and it is also the first to be recorded in Thailand’s marine waters. Alongside molecular information, this study contributes vital information beneficial for the taxonomy and biodiversity of capillariids in marine fishes.

This study reports the first rediscovery and redescription of Euclinostomum lauroi in more than 40 years, based on an adult specimen recovered from the oesophagus of a great white pelican (Pelecanus onocrotalus) in Lake Tana, Ethiopia. An integrative taxonomic approach combining detailed morphological examination and molecular analyses (ITS rDNA and COI mtDNA) was employed. Scanning electron microscopy revealed additional features, including the fine surface morphology of the cirrus and genital opening. The same host individual harboured 2 Clinostomum species, C. phalacrocoracis and C. tilapiae, for which updated morphological redescriptions are provided. The record of C. tilapiae represents a new geographical record for Ethiopia. These findings expand current knowledge of African clinostomid diversity and identify Lake Tana as an important hotspot of trematode biodiversity. The newly generated morphological and molecular data refine species boundaries within Euclinostomum and Clinostomum and support the use of integrative approaches to resolve persistent taxonomic uncertainties in clinostomid systematics.

Serpinema currently comprises 12 valid species of nematode parasites of freshwater turtles, distributed across the Neotropical, Oriental and Palearctic regions. Thus, we describe Serpinema yehi n. sp., a parasite of Rhinoclemmys punctularia from the Brazilian Amazon. Species identification was based on light and scanning electron microscopy, and molecular and phylogenetic analyses were performed using partial sequences of the mitochondrial cytochrome c oxidase subunit I and nuclear 18S genes. Serpinema yehi n. sp. can be distinguished from its congeners by the number of ridges in the buccal capsule, the number and arrangement of caudal papillae, the length and morphology of the right spicule, vulvar lip morphology and the number of mucrons on the female tail. Phylogenetic analyses recovered the new species as closely related to Camallanus, but not nested within the Camallanus spp. clade, thereby supporting the recognition of Serpinema as a valid genus. Serpinema yehi n. sp. represents the second species of the genus described from R. punctularia and the eighth species recorded from Brazil.

Parasite transmission can be disrupted when their free-living larval stages are consumed by non-host organisms. Yet, the contribution of benthic scrapers to this process remains insufficiently explored. Here, we experimentally assessed the ability of the North American pulmonate snail Physa acuta to reduce the abundance of free-living digenean larvae – cercariae of Diplostomum sp. and Trichobilharzia sp., and adolescariae of Notocotylus sp. – and evaluated how this effect is modulated by snail body size and colonisation by other organisms. Larval consumption by P. acuta occurred in all treatments and was highest for settled Notocotylus sp. adolescariae, particularly among larger individuals. The extent of larval reduction varied with infection by digenean metacercariae (xiphidiometacercariae), which either enhanced or inhibited feeding depending on parasite identity. It also varied with colonisation by Chaetogaster limnaei limnaei, whose presence increased the ingestion of planktonic cercariae, likely due to the combined feeding activity of the snail and its commensal oligochaete. Most snails harboured metacercariae, indicating that P. acuta frequently functions as a second intermediate host in its non-native range. Our findings highlight the dual ecological role of P. acuta – both as a consumer of free-living parasite stages and as a competent host. This trophic interaction may disrupt parasite transmission while providing nutritional benefits that support the ecological success and spread of this non-native species. Conversely, by serving as a host, P. acuta may facilitate the persistence and dissemination of parasitic taxa in invaded ecosystems.

The latitudinal patterns of the phylogenetic, functional and numerical interaction specificity (PIS, FIS and NIS, respectively) of fleas and mammals in their interaction networks, from 4 biogeographic realms, were investigated at the intraspecific, interspecific and community levels to understand whether the spatial variation of interaction specificity followed the predictions of a latitudinal specialization gradient. In fleas, no latitudinal pattern of PIS was detected. Flea FIS varied with latitude in all realms at the intraspecific level and in 2 realms at the interspecific and community levels. Latitudinal trends in NIS were detected in all realms (except Neotropics) at the intraspecific level and in the Old World realms at both higher levels. In hosts, PIS varied with latitude in the Afrotropics and the Nearctic at the intraspecific level and in the Afrotropics at the interspecific and community levels. FIS demonstrated a latitudinal trend in the Nearctic at the intraspecific level and in the Palearctic at the community level. Relationships between latitude and NIS were found in all realms (except Neotropics) at the intraspecific level and in the Old World realms at the interspecific and community levels. The directions of the latitudinal pattern of the same specificity facet could be positive or negative. They differed between fleas and hosts, realms and organizational levels. The occurrence and direction of the latitudinal specialization gradient are explained by the combined actions of evolutionary, historical and ecological factors. Pooling data from regions with different biogeographical histories and landscape structures, for a macroecological analysis, may produce spurious results.