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.

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.

Parasitic worms have significant medical, veterinary and economic importance. Numerous studies have therefore addressed various aspects of parasitic worms’ biology. In contrast, the ploidy of parasitic worms remains comparatively understudied, despite a few known triploid species. Polyploidy is known to have phenotypic and genetic effects in animals, which can lead to changes at the evolutionary scale. The evolutionary consequences of polyploidy have been addressed in host–parasite systems; however, most studies have focused on the host perspective, with relatively few studies examining the parasitic side of the story. This review provides available information on the distribution of triploidy among parasitic worms, along with information on such aspects as reproduction, origin of triploidy and life history. Across 100 selected papers (out of 416 screened), triploidy was reported for 15 parasitic Platyhelminthes and 13 parasitic Nematoda. Most triploid species of parasitic worms (24 out of 28) were documented at the adult stage. Triploid lineages reported for the adult stage reproduce predominantly via parthenogenesis. Finally, the paper discusses the potential effects of ploidy variation for host–parasite dynamics and adaptation rates of parasitic worms. In particular, how parasitic worms adapt to their hosts despite potential constraints of asexuality. As well as whether triploid individuals outcompete diploid conspecifics when both ploidy levels coinfect the host, as could be expected if triploids have higher virulence.

This is the first ultrastructural study of an adult tapeworm providing data on the morphological aspects of the pathways of lipid excretion via the tegumental surface and excretory system in the monozoic tapeworm Caryophyllaeus brachycollis (Janiszewska, 1953) from the chub Squalius tenellus (Heckel, 1843) obtained from a lake in the Bosnia-Herzegovina Federation. Our study has shown that the release of lipid droplets onto the parasite–host interface from the tegumental cytoplasm is carried out with the participation of tegumental vesicles, which clustered and fused with each other to form electron-lucent, membrane-bound sacs around lipid droplets. The ultrastructural pattern of the excretory bladder is presented for the first time for an adult tapeworm. In C. brachycollis, the syncytial epithelial lining of both the distal and proximal bladder is a derivative of the tegumental distal cytoplasm of the posterior body surface. Variations in the structural organization of both bladder parts were observed in the kinds of luminal microtriches and in the presence of large cytoplasmic protrusions in the proximal bladder. In C. brachycollis, the lipid droplets are released into the proximal bladder lumen via 10 collecting descending excretory ducts. In adult mature monozoic caryophyllidean tapeworms, an accumulation of a large number of sarcoplasmic lipid droplets is observed and their presence in the protonephridial cyrtocytes is revealed at the posterior body end, where there are the reproductive organs and ducts.

In a parasitological survey conducted in 2025 at a fish farm in Kunming, southwest China, a new diplozoid species was discovered on Garra surgifrons, representing the first record of a diplozoid previously reported from fish within the genus Garra in China. Morphological and molecular evidence confirm that the new species is clearly differentiated from Paradiplozoon bingolensis, the only diplozoid previously reported from Garra fishes. Phylogenetic analyses place the new species at the basal position of Chinese Paradiplozoon species. Considering the natural distribution of its host in Yunnan province and adjacent areas of Myanmar and Laos, southwestern China and Southeast Asia may represent important centres of origin and diversification for East Asian Paradiplozoon species. This study highlights the underestimated diversity, host specificity and biogeographic structure of diplozoids in East Asia and underscores the need for expanded sampling in Yunnan and neighbouring Southeast Asian regions.

Zoonotic parasites are a growing concern in regions where humans, domestic animals and wildlife live in close proximity. Understanding parasite communities overlap across hosts is essential for understanding transmission risks. In this study, we used sedimentation technique followed by microscopy, and molecular techniques for the identification of strongylid nematodes, Strongyloides, and protists in vervet monkeys (Chlorocebus pygerythrus, N = 75), household latrines (N = 25), dogs (Canis lupus familiaris, N = 25) and livestock (Ncows = 9, Ngoats = 7, Npigs = 9) at Lake Nabugabo, Uganda to compare parasite assemblages across hosts within the same habitat. We identified 33 unique parasite taxa with 18 in dogs, 14 in livestock and 10 each in vervets and latrine samples. There was a significant difference in the parasite infection rate between vervets (88%), latrines (24%), livestock (44%) and dogs (40%). Samples harboured at least 7 known genera of strongylid nematodes, with Ancylostoma, Murshidia and Oesophagostomum being the most prevalent. Protists diversity varied across hosts. Species-specific Cryptosporidium taxa occurred in dogs, goats (Capra aegagrus hircus) and pigs (Sus scrofa domesticus), and C. andersoni was detected in both dogs (4%) and cows (Bos taurus, 8%). Giardia intestinalis assemblage A was found in vervets (1.3%), dogs (16%) and latrine samples (12%). Enterocytozoon bieneusi occurred only in latrine samples, while Encephalitozoon sp. occurred only in vervets (4%). Our results show limited overlap between vervets and other hosts but highlight shared Giardia among animals and latrine samples, indicating key points of potential zoonotic transmission in this human-modified landscape.

Moose are significant ecological, economical and cultural animals for the stakeholders of Alaska, USA. Thus, the impact of pathogens, like filarial nematodes, is a critical area of moose research. These vector-borne parasites, including Setaria yehi, and Rumenfilaria andersoni, can lead to severe health consequences (e.g., peritonitis). However, little is known about filarial nematode distribution, diversity and its associated life cycle with Alaskan moose hosts. Newly developed next-generation sequencing techniques offer the ability to efficiently screen multiple species of co-infecting filarial nematodes in a single sample and thus improve our ability to monitor and understand these parasites. Blood collected from wild moose in the Kenai Peninsula, AK, was screened using deep amplicon sequencing (DAS) with filarial nematode primers targeting the cytochrome oxidase c subunit 1 (cox1) gene. In addition, samples subjected to DAS were also screened using the Modified Knott’s Test (MKT). Setaria yehi and R. andersoni were detected by both diagnostic methods. Overall, 190 moose samples were tested via DAS, with filarioid DNA being detected in 51.58% (98/190) of these. Out of a subset of 138 samples, filarioid nematodes were found in 50.72% (n = 70) and 57.25% (79/138) via DAS and MKT, respectively. However, 18 (13.04%) co-infections were detected by DAS compared to 12 (8.70%) identified via MKT. A DAS molecular tool for surveillance has several advantages when paired with host blood collection metadata (i.e., years, season, region, host age) to better understand filarial nematode life cycle and ecology.

Parasitic diseases, including scabies and pediculosis, pose significant public health concerns, particularly in developing countries. Despite their non-lethal nature, these diseases can cause considerable morbidity. This study aimed to assess the national and subnational burden of scabies and pediculosis in Ecuador during 2021 and explore the spatial correlations between these diseases and environmental factors. An observational, cross-sectional study was conducted using 2021 outpatient data from Ecuador’s Ministry of Public Health. Municipal incidence rates were calculated for scabies (ICD-10 B86) and pediculosis (ICD-10 B85). Local Indicators of Spatial Association analysis was performed to identify epidemiological hot and cold spots. Associations with climatic variables (rainfall, temperature and altitude) were examined using Wilcoxon tests and ordinary least squares regression. A total of 20 722 scabies cases and 3558 pediculosis cases were identified, with national incidences of 118.45 and 20.33 per 100 000 population, respectively. Both diseases were more frequent in women. Scabies hot spots were located in the Coast and Amazon regions and associated with higher rainfall, higher temperature and lower altitude. Pediculosis hot spots were located exclusively in the Amazon region and associated with higher rainfall and higher altitude. Climatic factors explained 24.3% of scabies variance but only 6.3% for pediculosis. This study underscores the importance of climatic and socio-environmental factors in the transmission of scabies and pediculosis and provides valuable epidemiological data for future control efforts in Ecuador.

Parasitic arthropods often depend on symbiotic microbes to supplement their narrow diets. Facultative parasites exhibit variation in their parasitic activity and diet, and thus, might be expected to have greater variation in their microbial communities. Further, individuals that engage in more parasitic activity may have different microbial communities from those less parasitic within the same population, but this remains unexplored. Here, we compared the microbial communities of individuals exhibiting parasitic (n = 30) and nonparasitic (n = 29) tendencies from two populations (one originating from Tampa, FL and the other Gainesville, FL) of facultatively ectoparasitic mites (Macrocheles muscaedomesticae). Microbial alpha diversity was similar across mites, regardless of parasitic activity or population. Using ANOSIM, we found that our dataset clustered into four groups. The composition of microbial communities of non-parasitic M. muscaedomesticae mites originating from Tampa and Gainesville was distinct from each other, whereas the parasitic mites had a much greater degree of overlap. We hypothesize that the association of parasitic individuals with fly hosts drove the observed overlap in their microbial communities.

Large gulls (Laridae) have expanded from coastal regions into inland Central Europe, where they increasingly exploit fishponds, landfills, and urban habitats. This shift alters their exposure to trematode parasites and their role in linking parasite transmission across ecosystems. We examined the trematode communities of 5 gull species (Larus argentatus, Larus cachinnans, Larus canus, Larus hyperboreus, and Larus marinus) collected in the eastern Czech Republic between 2022 and 2025. Complete helminthological examinations were performed on 207 individuals. Trematodes were detected in 82% of the birds, but the infection patterns differed among host species. Assemblages were overwhelmingly dominated by freshwater-transmitted taxa associated with cyprinid fish, particularly Diplostomum spp. and related genera. Pond-foraging gulls (L. argentatus and L. cachinnans) presented high prevalence, richness, and infection intensity, with frequent co-infections indicating repeated exposure within freshwater food webs. In contrast, L. canus and landfill-associated birds were often uninfected or lightly infected, reflecting limited participation in aquatic transmission cycles. Marine and brackish trematodes occurred sporadically and at low intensities, which is consistent with carry-over infections acquired in coastal regions without inland transmission. Community assemblages at the individual-host level were aggregated and consistent with stochastic exposure once the host species were considered. Maturity had little influence on helminth richness or diversity in gulls. Trematode assemblages closely reflected gull foraging strategies and habitat use, indicating that freshwater pond systems are the primary settings in which inland gulls may influence parasite transmission.

Plasmodium vivax RH5-interactive putative protein (RIPR) is present in micronemes and might participate in erythrocyte invasion. In this study, the polymorphism of pvripr gene was examined. In 7 P. vivax isolates from southern Mexico (SM), the pvripr gene was amplified and sequenced. Other pvripr sequences were retrieved from PlasmoDB; 15 from SM and 78 from other locations. The genetic parameters, deviation from neutrality, Z selection test, haplotype networks, FST index of differentiation and the amino acid substitutions were analysed. The phylogenetic tree of 22 SM isolates suggested 2 genetic groupings, and these isolates had lower nucleotide diversity (n = 22; π = 0.0007, Hd = 0.671) than Colombian, Peruvian and Asian parasites (π = 0.0011–0.0017, Hd > 0.9). The haplotype network of Mexican pvripr had haplotypes separated by 1–13 mutational steps among them, and a complex structure was observed in parasites from Peru, Colombia and China. No significant deviation from neutrality was estimated; however, Tajima’s D values across 3′ segment were negative in parasites from all locations. The Z test was significantly positive only for Latin American parasites, and the codon-level selection analysis showed several codons with dN–dS positive values in East Asia and Southeast Asia parasites. Given the lack of long-term in vitro culture for P. vivax, in silico epitope mapping across global sequences provides a pragmatic, hypothesis-generating framework. Globally, 12 polymorphic residues involved charged amino acid changes, many within predicted B-cell epitopes, consistent with immune-mediated selection on PvRIPR.