Autoradiographs revealed that sporocysts of Cercaria helvetica XII and rediae of Sphaeridiotrema globulus, incubated in a medium containing [14C]-glucose, exhibited slight radioactivity in their body wall after only 30 seconds incubation. Activity in sporocysts and rcdiae gradually increased as the incubation period was extended until after 4 minutes, a heavy reaction was observed in the parasite body wall as well as in the germ balls and developing cercariae within the parasite brood chambers. The redial caecum appeared to incorporate the labelled compound much more intensely than did the redial body wall.

When uninfected Bithynia tentaculata, as well as B. tentaculata infected with either S. globulus or C. helvetica XII, were maintained in pond water containing [14C]-glucose, activity could be detected in the gills of both infected and uninfected snails after 5 hours incubation. After 12 hours a much heavier labelling was apparent in the gills, together with moderate activity in the haemocoelic spaces, foot musculature, stomach wall, and gut contents. After 20 hours a more intense labelling was apparent in these regions of the snail body and, in addition, some activity could be detected in the digestive gjand tubules of the host and, in infected snails, in the bodies of developing parasites. After 30 hours incubation the labelled compound had become incorporated into most of the host tissues but was most intense in the digestive gland tubules. Heavy activity was also evident in the parasites at this stage although certain cystogenous gland cells of the cercariae of both parasite species did not incorporate the labelled compound.

Host: Cebus fatuellus. Habitat: Stomach. Locality : South America. Two males and two females were collected from the stomach of a Brown Capucin. The two males are respectively 37 and 41 mm. long by 1.5 and 1.65 mm. thick; the two females are respectively 54 and 60 mm.long by 2.9 and 2.75 mm. thick in their posterior third.

Several specimens of this species were collected by the writer from the intestine of the Nile soft shelled turtle Trionyx triunguis (Forskal) (= T. niloticus) from the White Nile near Khartoum area in the Sudan.

Three cestodes are described from the black-winged stilt, Himantopus himantopus himantopus from Ghana.

1. Himantocestus blanksoni gen. et sp. nov. (Diploposthidae Poche, 1926) from the duodenum.

2. Infula burhini Burt, 1939 (Dioecocestidae Southwell, 1930) from the duodenum.

3. Thomasitaenia nunguae gen. et sp. nov. (Progynotaeniidae Fuhrmann, 1936) from the rectal caeca.

Tapeworms of the family Gryporhynchidae are endoparasites of fish-eating birds distributed worldwide. Currently the family contains 16 genera classified on the basis of the morphology of the rostellar apparatus, rostellar hooks and strobilar anatomy. However, the phylogenetic relationships among the genera are still unknown. In this study, sequences of the near complete 18S (SSU) and 28S (LSU) from rDNA of 13 species of gryporhynchids (adult specimens) representing eight genera (Cyclustera, Dendrouterina, Glossocercus, Gryporhynchidae gen. sp., Neovalipora, Paradilepis, Parvitaenia, Valipora) and one species of metacestode from fish (Neovalipora) were generated. Additionally, sequences of metacestodes of the genera Amirthalingamia, Neogryporhynchus, Paradilepis, Parvitaenia and Valipora from Africa recently added to the GenBank database were analysed. Phylogenetic relationships were inferred using maximum-likelihood (ML) and Bayesian inference of each (SSU and LSU) dataset. The phylogenetic analyses indicated that the family Gryporhynchidae is a well-supported monophyletic group within the Cyclophyllidea. The trees inferred with SSU and LSU datasets had similar topologies and suggested that the genera Glossocercus (two species sequenced) and Paradilepis (four spp.) are monophyletic. In contrast, Dendrouterina, Parvitaenia and Valipora are paraphyletic, suggesting that the species composition of these genera should be critically reviewed. Interestingly, species of the genera that use the same groups of definitive hosts such as herons (Ardeidae), cormorants (Phalacrocoracidae) and ibis (Threskiornithidae) are together in the phylogenetic tree, even though they differ markedly from each other in some morphological characters, especially shape and size of rostellar hooks.

A comparison of commonly occurring metazoan parasites in the digestive tract was made between common eiders, Somateria mollissima, that were contaminated with oil and reference birds confiscated from illegal hunting. There was a greater number of commonly occurring parasites and their abundance in reference than in oiled eiders. Except for an acanthocephalan, Polymorphus botulus, which was embedded in the wall of the intestinal tract, most of the other taxa of parasites, including trematodes, cestodes and nematodes, were probably voided from the birds following ingestion of oil. Reference eiders harboured fewer species and a substantially lower mean abundance of parasites than those studied in Newfoundland and Labrador more than four decades ago; this may be a signal of a changing prey base or an increase in prey availability as winter ice cover continues to decline.

Gyrodactylus sprostonae Ling, 1962 is a highly invasive parasite reported across freshwater environments of the northern hemisphere. The taxon was originally described from Carassius auratus (Linnaeus, 1758) and Cyprinus carpio Linnaeus, 1758 in China. This parasite has never been reported in Africa or the southern hemisphere. Recently, this taxon was collected from an indigenous yellowfish, Labeobarbus aeneus (Burchell, 1822), in the Vaal River, South Africa. The present study includes the conclusive identification of the gyrodactylid parasites collected from L. aeneus, including additional taxonomic data, using microscopy and molecular techniques. Microscopy included light microscopy (LM) of whole worms and scanning electron microscopy (SEM) of isolated haptoral sclerites. Additionally, morphometric data were obtained from SEM and compared to that generated using LM. For molecular analysis, the internal transcribed spacer (ITS) region of rDNA was amplified and phylogenetic topologies constructed. The specimens were morphometrically and genetically highly similar to other data for G. sprostonae. Additional point-to-point measurements and ITS rDNA sequences were generated for the taxon, contributing to the morphometric and molecular data for G. sprostonae. The study also includes the first study of the isolated haptoral sclerites of the taxon using SEM, with similar morphometric results to LM. This is the first record of G. sprostonae in the southern hemisphere and from a new, indigenous African host, L. aeneus, indicating host switching to smallmouth yellowfish. Furthermore, these results expand on the knowledge of the distribution of invasive parasites in South Africa, as well as Gyrodactylus species diversity in Africa.

Calodium hepaticum is a zoonotic nematode with a worldwide distribution. Although the host range of C. hepaticum includes a wide spectrum of mammals (including humans), this parasite is predominantly associated with the families Muridae and Cricetidae. Several Sigmodontinae species from Argentina were found to be infected by C. hepaticum, with a high prevalence in Akodon azarae. The present study focuses on C. hepaticum eggs from natural infection of three species of sigmodontine rodents from Argentina. Eggs were genetically characterized (intergenic 18S rRNA region). The objectives of this work are: (i) to propose a new analytical methodology; and (ii) to morphologically characterize C. hepaticum eggs, from three Sigmodontinae species (A. azarae, Calomys callidus and Oligoryzomys flavescens). Analyses were made by the Computer Image Analysis System based on the new standardized measurements and geometric morphometric tools. The resulting factor maps clearly illustrate global size differences in the parasite eggs from the three Sigmodontinae species analysed. The degree of similarity between egg populations was assessed through pairwise Mahalanobis distances, showing that the largest distances were detected between parasite eggs from C. callidus and O. flavescens. Herein, the phenotypical plasticity of C. hepaticum eggs is shown. Significant positive correlations were obtained between each egg parasite principal component 1 and rodent corporal characteristics: weight; liver weight; rodent length; and rodent body condition. The usefulness of the geometric morphometric analysis in studies of the relationship between C. hepaticum and its host must be highlighted. The high prevalence observed in A. azarae, associated with the wide size range of the parasite eggs evidenced by principal component analysis, suggests A. azarae to be the Sigmodontinae host species that plays the most important role as reservoir host for C. hepaticum in the New World.

Neglected tropical diseases (NTDs) share certain traits: they are parasitic infections, prevailing in tropical environments and affecting marginalized sectors of the population. Six NTDs – ascariasis, cysticercosis, echinococcosis, hookworm infection, onchocerciasis and trichuriasis – all of them endemic in Latin America and the Caribbean (LAC), are analysed in this work. This review aims to discuss key information on the function of excretory/secretory (E/S) proteins from these parasites in their infectivity, pathogeny and diagnosis. The modulation of the host immune system to favour the permanence and survival of the parasite is also discussed. An updated knowledge on the function of E/S molecules in endemic parasitoses in LAC may lead to new approaches for the clinical management and diagnosis of these diseases. In turn, this could allow us to optimize their treatment and make it more affordable – a relevant goal given the economic constraints that the region is facing.

Next generation sequencing technologies have facilitated a shift from a few targeted loci in population genetic studies to whole genome approaches. Here, we review the types of questions and inferences regarding the population biology and evolution of parasitic helminths being addressed within the field of population genomics. Topics include parabiome, hybridization, population structure, loci under selection and linkage mapping. We highlight various advances, and note the current trends in the field, particularly a focus on human-related parasites despite the inherent biodiversity of helminth species. We conclude by advocating for a broader application of population genomics to reflect the taxonomic and life history breadth displayed by helminth parasites. As such, our basic knowledge about helminth population biology and evolution would be enhanced while the diversity of helminths in itself would facilitate population genomic comparative studies to address broader ecological and evolutionary concepts.

Paramphistomosis is a parasitic disease endemic in ruminants nearly worldwide. In the present study, an in vitro screening of the main anthelmintics used in Mexico was carried out to determine the mean lethal dose for rumen fluke eggs from cattle in a humid, warm region. Rumen flukes were obtained from cattle slaughtered in the states of Tabasco and Chiapas in Mexico. Eggs were collected using a 37-μm sieve and quantified. Then, an in vitro incubation study was performed: 100 eggs were placed into the wells of polystyrene microtiter plates. Anthelmintic products were tested on the eggs at concentrations ranging from 0.0015 to 3.0 mg/ml for rafoxanide, 0.0025 to 10.20 mg/ml for nitroxinil and 0.0015 to 3 mg/ml for closantel to determine the median lethal dose (LD50) and maximum lethal dose (LD99). A control group (water) was included in each plate. Three different species of rumen flukes (Calicophoron brothriophoron, Calicophoron clavula and Paramphistomum cervi) belonging to five isolates were identified. Nitroxinil had the highest efficacy against rumen fluke eggs, with an LD50 of 0.11 to 65 μg/ml, whereas rafoxanide showed the lowest efficacy with an LD50 ranging from 500 to 1713 μg/ml. Closantel showed high variability in the LD50 among the different analysed isolates (17 to 122 μg/ml). The evaluated flukicidal drugs presented differential efficacy against the development of rumen fluke eggs. The efficacy of the drugs will vary depending on the geographical area of origin of the animals.

A survey of the gastrointestinal helminth communities of a population of Chalcides sexlineatus Steindachner, a small skink endemic to Gran Canaria island (Canary Archipelago, Spain), was conducted to determine the prevalence, abundance and species diversity of intestinal parasites in these reptiles. Only three parasite species were found, one cestode, Oochoristica agamae Baylis, 1919 and two nematodes, Parapharyngodon micipsae (Seurat, 1917) and Pharyngodonidae gen. sp. Helminth infracommunities of C. sexlineatus showed low values of abundance and species richness and diversity, being more similar to the helminth community of Tarentola boettgeri boettgeri (Steindachner) rather than those of Gallotia stehlini (Schenkel), both syntopic with the sampled host.

Clinostomidae is a diverse family of digenean parasitizing fish-eating birds as adults and fishes as metacercariae. The species composition, within the genus Clinostomum has been steadily increasing in recent years. In Argentina, four named species of Clinostomum have been documented, accompanied by four metacercariae representing distinct genetic lineages whose adults have not been identified. This study focused on examining clinostomids in three fish species – Australoheros scitulus (ASI), Cichlasoma dimerus (CDIM), and Pimelodella laticeps (PLA) – at various localities in Argentina. We conducted both morphological and molecular characterizations of the Clinostomum metacercariae collected from these fish species. Molecular phylogenetic analyses using COI mtDNA were performed to determine the placement of these metacercariae within the clinostomid phylogenetic tree. Clinostomum ASC represents a distinct lineage, morphologically distinguishable from other sequenced metacercariae due to its body shape (widest anteriorly and becoming slender towards the posterior end); this lineage was found to be closely related to C. caffarae. While Clinostomum CDIM and Clinostomum PLA exhibited morphological differences, they clustered together genetically with metacercariae reported in previous studies as Clinostomum L3 and Clinostomum CVI. This outcome, coupled with a low genetic distance (0 to 3%), suggests that they are conspecific with metacercariae found in fish across Mexico, Costa Rica, and Argentina. In light of the extensive diversity of fish species in Argentine freshwater ecosystems (over 500 species), and considering the relatively constrained extent of prior investigations, the anticipation of unearthing additional Clinostomum species or lineages is plausible.

The metacestode stage of Echinococcus granulosus is of zoonotic importance. In general, the 14-3-3 protein is involved in multiplication and survival of eukaryotes. Therefore, this communication presents succinct information on relative expression of the 14-3-3 protein in six different morphotypes of cysts of E. granulosus. All isolated E. granulosus belonged to the common sheep strain (G1). Relative expression of the 14-3-3 protein was higher in fertile cysts when compared to sterile cysts. The predicted amino acid sequence of the 14-3-3 protein was closely clustered with zeta-type isoforms 1 and 2 of the 14-3-3 protein. In addition, the present study demonstrates the presence of the 14-3-3 protein which until now had not been detected in the germinal layer. Our findings indicate that the expression of this biomolecule in the germinal layer of sterile organisms may contribute to the development and survival of the parasite in the host. The uniform expression of actin II conclusively proves the survivability of the harvested organisms.

Polycephalic larvae of Taenia endothoracicus were found from naturally infected gerbils Meriones lybicus in a rural area of Arak, central Iran. A large cyst containing 19 protoscolices was located in the peritoneum, attached to the large omentum. The characteristics of the protoscolices and rostellar hooks confirmed the identification of these larvae as T. endothoracicus.

Two new species of Diaphorocleidus and one new species of Rhinoxenoides n. gen. are described from the gills of Acestrorhynchus falcatus (Bloch) from rivers of north-eastern Pará, Brazil. Diaphorocleidus jaymedeloyolai n. sp. is characterized by a male copulatory organ (MCO) possessing three counterclockwise coils; similar anchors with subtriangular superficial roots; a ventral bar with posteromedial projection; and hooks of pairs 1, 4 and 7 approximately three times longer than hook pair 5. Diaphorocleidus sclerocolpus n. sp. differs from its congeners by a dual-branched accessory piece articulated with the MCO and a sclerotized tubular vagina with a bottle-shaped vestibule. Rhinoxenoides n. gen. is proposed and is characterized by possessing: MCO sclerotized with clockwise coils; an accessory piece articulated to the base of MCO; a sinistroventral vaginal aperture; ventral anchor with conspicuous roots; dorsal anchor with superficial root five times longer than deep root; and absence of dorsal bar. The proposal of Rhinoxenoides n. gen. is also supported by its phylogenetic relationship with Protorhinoxenus prochilodi and species of Rhinoxenus, using 16 morphological characters, which resulted in the following hypothesis of sister-group relationships: Rhinoxenoides n. gen. [Protorhinoxenus (Rhinoxenus curimatae (R. nyttus (R. bulbovaginatus (R. guianensis, R. piranhus, R. euryxenus (R. arietinus, R. anaclaudiae)))))].

Parasitic ‘turbellarians’ are known from various animals such as echinoderms, crustaceans, annelids, bivalve and gastropod molluscs. So far, however, no ‘turbellarians’ have been reported from cephalopods. In this paper we report a parasitic ‘turbellarian’ from the giant Antarctic octopus, Megaleledone setebos. We dissected two specimens of M. setebos caught in the Ross Sea (Antarctica) and found numerous worms in their intestine and liver. The worms were spherical or oblong and had two morphologically different poles. The frontal pole bears a small conical protrusion containing large elongated pear-shaped frontal glands and large polygonal cells. The ducts of the frontal glands open terminally to form the frontal organ. The caudal pole has an opening shaped as a folded tube connected by the genital pore with a common genital atrium, which continues into a canal with a muscular sheath. The worms were identified as ‘turbellarians’ from the family Notenteridae (Fecampiida). This family contains only one species, Notentera ivanovi, reported from the gut of a polychaete at the White Sea. The worms that we found in the gastrointestinal tract of the octopuses were morphologically similar to N. ivanovi but differed from it in several important respects. Phylogenetic analysis based on 28S rDNA gene showed that the newly found worm clustered together with other fecampiids in a highly supported clade and was closely related to N. ivanovi. On the basis of these morphological and molecular data, we described a new species, Octopoxenus antarcticus gen. nov., sp. nov. (Fecampiida: Notenteridae), establishing a new genus to accommodate it and provided an updated diagnosis of the family Notenteridae. This is the first report of a parasitic ‘turbellarian’ from a cephalopod mollusc.

Podocotyle is a genus of marine opecoelid digeneans that parasitize a wide variety of fish as adults. We present the first phylogenetic analysis of several Podocotyle isolates using nuclear 28S rDNA and mitochondrial cox1 DNA regions. New sequences were obtained for Podocotyle specimens from fish caught in the Sea of Okhotsk and the White Sea. Based on morphological and molecular data, eight Podocotyle lineages of species rank were revealed. However, this diversity is poorly formalized within the current taxonomic model of the genus. As a result, we identified Podocotyle cf. angulata, Podocotyle cf. atomon, Podocotyle cf. reflexa, Podocotyle atomon of Sokolov et al., 2019, Podocotyle sp. of Denisova et al., 2023, Podocotyle sp. 1, Podocotyle sp. 2 and Podocotyle sp. 3. We also highlight the unresolved question of the life cycles of representatives of Podocotyle whose intramolluscan stages parasitize the intertidal snails Littorina spp.

Climate change is expected to affect parasitic nematodes and hence possibly parasite–host dynamics and may have far-reaching consequences for animal health, livestock production, and ecosystem functioning. However, there has been no recent overview of current knowledge to identify how studies could contribute to a better understanding of terrestrial parasitic nematodes under changing climates. Here we screened almost 1,400 papers to review 57 experimental studies on the effects of temperature and moisture on hatching, development, survival, and behaviour of the free-living stages of terrestrial parasitic nematodes with a direct life cycle in birds and terrestrial mammals. Two major knowledge gaps are apparent. First, research should study the temperature dependency curves for hatching, development, and survival under various moisture treatments to test the interactive effect of temperature and moisture. Second, we specifically advocate for more studies that investigate how temperature, and its interaction with moisture, affect both vertical and horizontal movement of parasitic nematodes to understand infection risks. Overall, we advocate for more field experiments that test environmental effects on life-history traits and behaviour of parasitic nematodes in their free-living stages under natural and realistic circumstances. We also encourage studies to expand the range of used hosts and parasitic nematodes because 66% of results described in the available studies use sheep and cattle as hosts and 32% involve just three nematode species. This new comprehension brings attention to understudied abiotic impacts on terrestrial parasitic nematodes and will have broader implications for livestock management, wildlife conservation, and ecosystem functioning in a rapidly warming climate.

Abattoirs are vital for gathering information on animal diseases and protecting the public from consuming infected or unhygienic meat. To assess the major reasons for organ and carcass condemnations and their financial implications, we reviewed 10-year abattoir records of slaughtered bovines between January 2005 and December 2014 at Kombolcha ELFORA abattoir, north-east Ethiopia. Of the 46,913 cattle slaughtered during that period, 17,963 (38.3%) had at least one disease condition. Lungs (10.67%) and liver (25%) were the most affected and condemned organs, followed by heart (1.53%), head (0.56%), tongue (0.17%) and kidney (0.32%). The major conditions responsible for condemnation were fasciolosis (49.89%), hydatid cyst (55.55%), pericarditis (78.2%), hydronephrosis (35.8%), abscess (71.7%) and abscess (43.9%), in liver, lung, heart, kidneys, head and tongue, respectively. The direct financial losses incurred from organ and carcass condemnation over the 10-year period amounted to ETB 1,219,399 (USD 61,946.9), with parasitic diseases such as fascioliasis and hydatidosis accounting for ETB 256,837.5 (USD 13,047.64) and ETB 170,827.5 (USD 8678.23) in losses, respectively. This study describes a significant loss of cheap and reliable sources of protein due to non-utilization of infected organs or carcasses, emphasizing the need to implement integrated approaches in disease surveillance and control programmes.