Evidence of striking morphological similarity and tissue tropism of phylogenetically distant myxozoan genera: Myxidium and Paramyxidium in the kidney of the European eel.

European eel, Anguilla anguilla (Linnaeus) (Elopomorpha: Anguilliformes), is a critically endangered fish of ecological and economic importance, hosting numerous parasites, including myxozoans (Cnidaria). Since its initial discovery in the kidney of European eel, Myxidium giardi Cépède, 1906 has been reported with numerous spore sizes and shapes from various tissues of multiple anguillid species. Morphological variability, wide host and tissue spectrum, and lack of sequence data raised doubts about the conspecificity of reported isolates. Subsequent studies provided 18S rDNA sequences of several isolates from anguillids and other elopiform fish, and demonstrated a split of parasite data into two distinct phylogenetic lineages, one comprising the M. giardi sequence, and the other all species infecting elopiform fishes classified under the recently established genus Paramyxidium Freeman et Kristmundsson, 2018. Myxidium giardi was, however, transferred to this genus as Paramyxidium giardi n. comb. and designated as the type species of the genus. In line with this change, the sequence originally identified as M. giardi was considered to have been incorrectly associated with this species. To shed light on the status of M. giardi originally described by Cépède (1906), we conducted microscopic and molecular examinations of various organs of 24 individuals of European eel, originating from diverse Czech habitats. Through morphometric and molecular analyses, we demonstrated that spore and polar capsule morphology, morphometry and tissue tropism of our European eel kidney parasite isolates matched the features of the original M. giardi description. Our isolates clustered in the lineage encompassing the first published M. giardi sequence. Thus, the originally described M. giardi indeed represents an existing species within the genus Myxidium Bütschli, 1882, which we formally resurrect and redescribe. Due to the morphological and molecular differences between M. giardi and P. giardi of Freeman et Kristmundsson (2018), we additionally rename the latter species as Paramyxidium freemani nom. nov.

Clinical, histopathological and phylogenetic analysis of Myxobolus lentisturalis (Myxozoa: Myxobolidae) infecting the musculature of farmed population of goldfish (Carassius auratus) in Iran: 2021-2022.

There is a claimed increase in the global prevalence and incidence of emerging diseases observed in many organisms. Myxozoa represents an essential group of metazoan parasites that hold both economic and ecological significance. In the current study, 1% of the fish population at two commercial goldfish (Carassius auratus) farms in Tehran and Ghom province, Iran, developed cavitating muscular lesions resembling humps in February 2021 and January 2022. Fish displaying pathological abnormalities were transported to the Ornamental Fish Clinic and subjected to clinical examination. Light microscopy was subsequently used to examine wet smears of skin and gills, as well as whitish exudate. In addition, tissue homogenates were collected for more precise identification and molecular confirmation. The study discovered that individuals from the goldfish farms were infected with the pathogenic myxozoan Myxobolus lentisuturalis, which caused significant damage to the epaxial muscles. The spores collected from the humps had a lack of uniformity and were primarily ellipsoidal in shape. Histopathological analysis also revealed parasites in various stages of development, such as plasmodia and spores, as well as inflammatory cell infiltration (macrophage, giant cell and lymphoplasmacytic infiltration) between skeletal muscle fibers. Phylogenetic analysis of M. lentisuturalis was performed by using MEGA 11 and the maximum likelihood method. M. lentisuturalis is a myxozoan parasite that has been sparsely recorded and lacks widespread recognition. The current study is the first clinical, histopathological, and molecular characterization of M. lentisuturalis isolated from the skeletal musculature of goldfish (C. auratus) in Iran.

Solving the Myxidium rhodei (Myxozoa) puzzle: insights into its phylogeny and host specificity in Cypriniformes.

Myxidium rhodei Léger, 1905 (Cnidaria: Myxozoa) is a kidney-infecting myxosporean that was originally described from the European bitterling Rhodeus amarus. Subsequently, it has been documented based on spore morphology in more than 40 other cypriniform species, with the roach Rutilus rutilus being the most commonly reported host. This study introduces the first comprehensive data assessment of M. rhodei, conducted through morphological, ecological and molecular methods. The morphological and phylogenetic analyses of SSU rDNA sequences of Myxidium isolates obtained from European bitterling and roach did not support parasite conspecificity from these fish. In fact, the roach-infecting isolates represent three distinct parasite species. The first two, M. rutili n. sp. and M. rutilusi n. sp., are closely related cryptic species clustering with other myxosporeans in the freshwater urinary clade, sharing the same tissue tropism. The third one, M. batuevae n. sp., previously assigned to M. cf. rhodei, clustered in the hepatic biliary clade sister to bitterling-infecting M. rhodei. Our examination of diverse cypriniform fishes, coupled with molecular and morphological analyses, allowed us to untangle the cryptic species nature of M. rhodei and discover the existence of novel species. This underscores the largely undiscovered range of myxozoan diversity and highlights the need to incorporate sequence data in diagnosing novel species.

Title: Résoudre le casse-tête de Myxidium rhodei (Myxozoa) : aperçu de sa phylogénie et de sa spécificité d'hôte chez les Cypriniformes. Abstract: Myxidium rhodei Léger, 1905 (Cnidaria : Myxozoa) est un Myxosporea infectant les reins qui a été décrit à l'origine chez la bouvière, Rhodeus amarus. Par la suite, il a été documenté, sur la base de la morphologie des spores, chez plus de 40 autres espèces de cypriniformes, le gardon Rutilus rutilus étant l'hôte le plus fréquemment signalé. Cette étude présente la première évaluation complète des données sur M. rhodei, réalisée par des méthodes morphologiques, écologiques et moléculaires. Les analyse morphologiques et phylogénétiques des séquences d'ADNr SSU des isolats de Myxidium obtenus à partir de bouvières et de gardons européens n'ont pas confirmé la conspécificité du parasite de ces poissons. En fait, les isolats infectant les gardons représentent trois espèces distinctes de parasites. Les deux premières, M. rutili n. sp. et M. rutilusi n. sp., sont des espèces cryptiques étroitement apparentées, regroupées avec d'autres Myxosporea du clade urinaire d'eau douce, partageant le même tropisme tissulaire. La troisième, M. batuevae n. sp., précédemment attribuée à M. cf. rhodei, appartient au clade biliaire hépatique, groupe-frère de M. rhodei infectant la bouvière. Notre examen de divers poissons cypriniformes, couplé à des analyses moléculaires et morphologiques, nous a permis de démêler la nature cryptique des espèces de M. rhodei et de découvrir l'existence de nouvelles espèces. Cela souligne la diversité largement méconnue des Myxozoaires et souligne la nécessité d'incorporer des données de séquence dans le diagnostic de nouvelles espèces.

Investigation on parasitic infestation of Labeo rohita (Hamilton, 1822) in the south-western region of Bangladesh.

BACKGROUND: Our investigation focused into Labeo rohita, commonly known as Rui, a freshwater aquatic species in Bangladesh. Despite their nutritional significance, these fish faced a pressing challenge: parasite infections threaten the economic stability of the aquaculture sector. OBJECTIVES: The present study aimed to investigate the parasite and histological changes in major organs of L. rohita, collected from Khulna region - Dumuria, Paikgacha and Rupsha. METHODS: About 180 (30/month) specimens were collected between the month of March and August 2023 to observe the parasitic status in L. rohita. RESULTS: Through microscopic examination, a total of 323 parasites were uncovered, spanning categories including Cestode, Nematode, Acanthocephala, Trematode and Digenia, predominantly residing in the intestines of L. rohita. The highest prevalence rate (70%) was recorded in both March and May 2023, with peak mean intensity observed in July (3.73). Notably, the highest mean abundance (2.37) exhibited in July and index of infestation (45.34) in June. Histological analysis confirmed parasitic infestations in the gastrointestinal region, with displaying histological changes within major organs such as the liver, kidney, gills, spleen and testicles due to parasitic infection. CONCLUSION: This study concluded that the indentified six categories of parasite and the affect of parasitic infestation in major organs of L. rohita within the study period. Urgent efforts to implement effective strategies for controlling the parasite infections in aquaculture to ensure the sustainable production of this invaluable fish species.

The Tilapia Cyst Tissue Enclosing the Proliferating Myxobolus bejeranoi Parasite Exhibits Cornified Structure and Immune Barrier Function.

Myxozoa, a unique group of obligate endoparasites within the phylum Cnidaria, can cause emerging diseases in wild and cultured fish populations. Recently, the myxozoan Myxobolus bejeranoi has been identified as a prevalent pathogen infecting the gills of cultured hybrid tilapia, leading to systemic immune suppression and considerable mortality. Here, we employed a proteomic approach to examine the impact of M. bejeranoi infection on fish gills, focusing on the structure of the granulomata, or cyst, formed around the proliferating parasite to prevent its spread to surrounding tissue. Enrichment analysis showed increased immune response and oxidative stress in infected gill tissue, most markedly in the cyst's wall. The intense immune reaction included a consortium of endopeptidase inhibitors, potentially combating the myxozoan arsenal of secreted proteases. Analysis of the cyst's proteome and histology staining indicated that keratin intermediate filaments contribute to its structural rigidity. Moreover, we uncovered skin-specific proteins, including a grainyhead-like transcription factor and a teleost-specific S100 calcium-binding protein that may play a role in epithelial morphogenesis and cysts formation. These findings deepen our understanding of the proteomic elements that grant the cyst its distinctive nature at the critical interface between the fish host and myxozoan parasite.

Thermotactic behaviour in lacustrine and riverine forms of Salmo trutta and its relevance to an emerging parasitic disease (PKD) in the wake of climate change.

The thermotactic response of brown trout (Salmo trutta) was examined with the goal to investigate potential effects of the emerging temperature-dependent fatal trout disease PKD (proliferative kidney disease). First the differences in cold-water preferences of two forms of brown trout, lacustrine (migratory) and riverine, were determined. Second, it was studied whether this preference was changed in fish infected with PKD. The experiment involved a one-week habituation period at 14 °C in a two-chamber runway followed by a week of 3 °C temperature difference between the two runways. The fish could freely move between lanes via an opening at the end where food was provided. The temperature manipulation was repeated twice, and there were 3 trials per experimental group. All fish developed a clear spatial preference in the test. Lacustrine trout demonstrated a preference for warmer water, while riverine trout preferred cooler water. This may increase the risk to PKD in the lacustrine form. Most strikingly, riverine trout experimentally exposed to Tetracapsuloides bryosalmonae, the parasite that causes PKD, demonstrated stronger cold-seeking behaviour than control fish. Cold seeking behaviour suggests the occurrence of a disease-induced behavioural chill response, which may play an important role in disease recovery. This demonstrates the significance of protecting river connectivity and cold-water sanctuaries as management strategies for preserving salmonid populations in a warming climate.

Phylogenetic analysis of Ellipsomyxa species (Myxosporea) and description of Ellipsomyxa gordeyi n. sp. from the gall bladder of mullets (Mugiliformes: Mugilidae) in Nha Trang Bay of the East Sea, Vietnam.

The coastal waters of Vietnam are home to a wide diversity of fishes, but the parasite diversity of these potential hosts is much less well characterized. To begin addressing this knowledge gap, we carried out surveys of myxozoan parasites in fishes collected from Nha Trang Bay in Vietnam's East Sea in 2018-2019. Mugilid fishes were collected in March-April 2018, January-February 2019, and November-December 2019, and examined for myxozoans. Myxospores consistent with those of the genus Ellipsomyxa were found in the gall bladder of four mullet species, and we thoroughly characterized those from Planiliza melinoptera. Myxospores were elliptoid and devoid of striation, with a distinct sinuous suture line. Polar capsules were pyriform and oriented toward the poles of the spore. Morphological features were compared to nominal species and this species from Vietnam was distinct. Phylogenetic analysis based on partial small subunit rDNA sequence revealed that broadly, Ellipsomyxa species split into three phylogenetic lineages, and although in some branches there are groupings by host family, habitat or locality, there are no clear phylogenetic patterns. The new species we encountered in P. melinoptera had a close sister relationship with Ellipsomyxa adlardi, with both species part of a larger subclade within the Ellipsomyxa lineage. Despite this phylogenetic similarity, these species were morphologically distinct, and partial large subunit DNA sequences were only 93% similar to each other. A combination of the morphological characteristics and molecular data suggest that this is an undescribed species and we propose the name Ellipsomyxa gordeyi n. sp.

Novel insights into immune stress markers associated with myxosporeans gill infection in Nile tilapia (molecular and immunohistochemical studies).

Nile tilapia (Oreochromis niloticus) is valued in aquaculture because of its quick development and ability to thrive in various environments. Myxosporeans are among the fish parasites that affect fish productivity, as they impact fish growth and reproduction, resulting in large fish deaths in farms and hatcheries. This study has been focused on morpho-molecular identification for the myxosporean parasites infecting Nile tilapia from three governorates in Egypt and assessment of gene expression of different cytokines (Interleukin-1ßeta (IL-1ß), major histocompatibility complex class II (MHC-II), and clusters of differentiation 4 (CD-4) and 8 (CD-8)) in tissues. Additionally, this work aimed to correlate the developed histopathological alterations and inflammatory reactions in gills with immunohistochemical expression of inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-α). Finally, the infected fish's cortisol levels and blood glucose were assessed. Results of BLAST sequence analysis of the 18S rRNA for the collected protozoans confirmed Myxobolus agolus, M. brachysporus, M. tilapiae, and Henneguya species. The molecular characterization of the immunological status of gills revealed marked upregulation of different inflammatory cytokines in the gills of infected fish. There was a significantly increased serum cortisol and glucose level in infected fish compared with control, non-infected ones. Severe histopathological alterations were observed in the infected fish gills, associated with increased expression of iNOS and TNF-α and related to myxosporean infection. The present study provides new insights into oxidative stress biomarkers in Nile tilapia infected with Myxosporeans and elucidates the gill's immune status changes as a portal of entry for protozoa that contribute to tissue damage.

Occurrence of Myxobolus spp. (Myxozoa) in the blood of Metynnis lippincottianus (Osteichthyes: Serrasalmidae) from eastern Amazon, Brazil.

Myxozoans are obligatory parasites and can be found in various organs and bloodstreams of fish, thus, the objective of this work was to describe the occurrence of Myxobolus spp. in the circulating blood of Metynnis lippincottianus from River Curiaú, Macapá City, eastern Amazon, Brazil. The samples of M. lippincottianus (11) were caught using cast net and gillnets. The fish blood was collected by puncturing the caudal vessel, using needles and syringes containing 10% of EDTA solution. Blood smear were prepared and panchromatic stained with a combination of May Grunwald-Giemsa-Wright, for observation and examination of the parasitic structures in optical microscope. Tissues from the kidney was examined using specific stereoscopic binoculars to check for the presence of cysts, lesions and parasites. The prevalence of Myxobolus spp. infecting the circulating blood of the fish was 36.36% (4/11) and 15 spores of mixosporyds were visualized. Myxobolus spp. had a prevalence of 54.55% (6/11) in host's kidney tissue and the morphometric spores data converge with observed in the blood. The morphological characteristics of the spores in the blood samples revealed two morphotypes of Myxobolus spp. This is the sixth occurrence recorded of Myxobolus spp. infecting fish blood in Brazil.

Awareness of parasitic zoonotic diseases among pet owners in Cairo, Egypt.

Egyptians are becoming more interested in owning and raising pets; however, most of them lack essential awareness about the risk of zoonotic parasites that could be transmitted. The objective of the present investigation was to evaluate the degree of awareness Egyptian pet owners possess concerning zoonotic parasitic diseases, the risk of transmission, and preventative measures. A cross-sectional study was conducted using an e-survey. Among 246 pet owners, 64.2% (158) were females, and 67.9% (167) belonged to the 20-30 age group. The majority, 78.9% (194), were raising cats. Only 13.8% (34) visited the veterinarian regularly, with significantly higher results among dog owners (p < 0.05). Only 31.3% (77) participants were regularly deworming their pets, and 19.9% (49) were giving their pets prophylaxis against ectoparasites, with significantly higher results among those who visited the veterinarian regularly (p < 0.0001) and among dog owners (p < 0.05). Only 54.1% (133) had heard about the term "zoonoses" before, and about 8.9% (22) of participants showed a history of zoonotic parasitic diseases, with significantly higher results among those who allowed their animals to play with other animals of neighbors and friends (p < 0.05). The obtained results concluded that the surveyed group had a relatively good degree of knowledge regarding pets as a source of zoonotic illness; raising pet owners' awareness regarding the importance of routine medical examinations and minimizing the contact of pets with other stray animals is essential.

The myxozoans Myxobolus cerebralis and Tetracapsuloides bryosalmonae modulate rainbow trout immune responses: quantitative shotgun proteomics at the portals of entry after single and co-infections.

Introduction: Little is known about the proteomic changes at the portals of entry in rainbow trout after infection with the myxozoan parasites, Myxobolus cerebralis, and Tetracapsuloides bryosalmonae. Whirling disease (WD) is a severe disease of salmonids, caused by the myxosporean M. cerebralis, while, proliferative kidney disease (PKD) is caused by T. bryosalmonae, which instead belongs to the class Malacosporea. Climate change is providing more suitable conditions for myxozoan parasites lifecycle, posing a high risk to salmonid aquaculture and contributing to the decline of wild trout populations in North America and Europe. Therefore, the aim of this study was to provide the first proteomic profiles of the host in the search for evasion strategies during single and coinfection with M. cerebralis and T. bryosalmonae. Methods: One group of fish was initially infected with M. cerebralis and another group with T. bryosalmonae. After 30 days, half of the fish in each group were co-infected with the other parasite. Using a quantitative proteomic approach, we investigated proteomic changes in the caudal fins and gills of rainbow trout before and after co-infection. Results: In the caudal fins, 16 proteins were differentially regulated post exposure to M. cerebralis, whereas 27 proteins were differentially modulated in the gills of the infected rainbow trout post exposure to T. bryosalmonae. After co-infection, 4 proteins involved in parasite recognition and the regulation of host immune responses were differentially modulated between the groups in the caudal fin. In the gills, 11 proteins involved in parasite recognition and host immunity, including 4 myxozoan proteins predicted to be virulence factors, were differentially modulated. Discussion: The results of this study increase our knowledge on rainbow trout co-infections by myxozoan parasites and rainbow trout immune responses against myxozoans at the portals of entry, supporting a better understanding of these host-parasite interactions.

Health Assessment of Adult Male Eastern Wild Turkeys (Meleagris gallopavo silvestris) from Western Kentucky, USA.

Wild turkeys (Meleagris gallopavo) are an important game species throughout the geographic range. Populations throughout multiple regions of the US have been declining, including in Kentucky, US, raising concerns among managers and resource users. To better understand the overall population health, we performed postmortem examinations and targeted pathogen, mineral, and toxicant testing on 36 adult male, apparently healthy, wild turkeys that were hunter harvested in western Kentucky during April 2018. We found that birds were in fair to good nutritional condition with no significant gross or microscopic lesions. Ticks (Amblyomma spp.) and lice (three species) were present on 94 and 31% of birds, respectively. We commonly detected intestinal nematodes and cestodes and found coccidian oocysts in 39% and capillarid eggs in 6% of birds. The prevalences of lymphoproliferative disease virus and reticuloendotheliosis virus were 39 and 11%, respectively. Spleen samples tested with PCR were positive for Borrelia burgdorferi, Haemoproteus sp., and Leucocytozoon sp. in 11, 83, and 3%, respectively. Based on a subjective histologic assessment of testis tissues, most birds had widespread and abundant sperm present. Mineral analysis and broad toxicant screening on liver samples from 32 turkeys were unremarkable. Further work is needed to assess potential population risk factors and to determine individual- and population-level impacts of pathogens on adults and poults.

Exotic myxozoan parasites establish complex life cycles in farm pond aquaculture.

Myxozoans are obligate parasites with complex life cycles, typically infecting fish and annelids. Here, we examined annelids from fish farm pond sediments in the Beit Shean Valley, in the Syrian-African Rift Valley, Israel, for myxozoan infections. We examined 1486 oligochaetes, and found 74 (5 %) were infected with actinospore stages. We used mitochondrial 16S sequencing to infer identity of 25 infected annelids as species of Potamothrix, Psammoryctides, Tubifex and Dero. We identified 7 myxozoan types from collective groups Neoactinomyxum and Sphaeractinomyxon, and characterized them by small subunit ribosomal DNA sequencing. The Neoactinomyxum type was genetically most similar (∼93 %) to cyprinid fish-infecting Myxobolus spp. The six Sphaeractinomyxon types were genetically similar (93-100 %) to Mugilid-infecting Myxobolus spp.; with one being the previously unknown actinospore stage of a myxospore that infects mullet from aquaculture from the Israeli coast of the Mediterranean Sea. As the farm pond system is artificial and geographically isolated from the Mediterranean, the presence of at least seven myxozoans in their annelid hosts demonstrates introduction and establishment of these parasites in a novel, brackish environment.

New molecular evidence on the members of the genus Ortholinea (Cnidaria, Myxozoa) and the description of Ortholinea hamsiensis n. sp. infecting the urinary bladder of European anchovy Engraulis engrasicolus in the Black Sea.

Members of the genus Ortholinea are among the worldwide distributed myxozoan parasites that mainly infect marine fish. In this study, a new myxosporean species, Ortholinea hamsiensis n. sp., was isolated from the urinary bladder of European anchovy Engraulis engrasicolus collected from the Sinop coasts of the Black Sea. The prevalence and density values of infection were 1.4% and 1­5 individuals in the field of view (1 + ), respectively. Mature myxospores are subspherical with slight tapering down to the less pronounced tip in the frontal view and subspherical in the sutural view. Myxospores measured 9.1 ± 0.25 (8.8­9.9) µm in length, 9.2 ± 0.11 (8.9­9.4) µm in thickness, and 8.4 ± 0.33 (8.2-9.1) µm in width. Two polar capsules equal in size measured 3.1 ± 0.11 (3.0­3.3) µm in length and 2.7 ± 0.11 (2.6­2.9) µm in width. The polar tubule had 3­4 coils. Along with morphological peculiarities, the results of the 18S rDNA also revealed it to be a new species for science compared to the other species of the genus. In this study, another myxosporean species O. gobiusi was also detected in round goby Neogobius melanostomus with a prevalence of infection value of 4.8% and a density of 1­5 individuals in the field of view (1 + ). The present study also provided the first data of 18S rDNA of O. gobiusi from N. melanostomus and type species of the genus O. divergens from Gobius niger and the phylogenetic relationships of these species with other Ortholinea species have been revealed.

Comparative Analysis of Parasite Load on Recently Established Invasive Pumpkinseed Lepomis gibbosus (Actinopterygii: Centrarchidae) in Europe.

PURPOSE: The aim of this study was the comparative analysis of the parasite communities of new populations of invasive pumpkinseed (Lepomis gibbosus) in western Ukraine with pumpkinseed from Czechia, where populations have rapidly expanded over the last two decades. METHODS: Sampling took place at three localities in the western part of Ukraine (i.e. Dobrotvir Reservoir (Vistula basin), Burshtyn Reservoir (Dniester basin), Mynai Pond (Danube basin)) and four in Czechia (i.e. Oxbow D2, Herspický Pond (Danube basin), and Kolín oxbow and Rímov Reservoir (Elbe basin). RESULTS: In total, 11 parasite taxa were recorded in Ukraine and 17 in Czechia. Four species were co-introduced from North America with their host, i.e. the myxosporean Myxobolus dechtiari, the monogeneans Onchocleidus dispar and Onchocleidus similis, and metacercariae of a trematode Posthodiplostomum centrarchi. High dominance indices were related to a high abundance of co-introduced parasites, i.e. O. similis in Mynai pond and P. centrarchi in Dobrotvir Reservoir. Overall abundance of acquired parasites was generally low. CONCLUSION: This study shows that parasite communities in recently established pumpkinseed populations in the western part of Ukraine and Czechia are less diverse than those established in Europe for decades. The generally low parasite load in these new populations may play an important role in their ability to successfully establish and create strong populations by providing a competitive advantage over local species.

ParSCo: celebrating 10 years of a unique parasitology summer course.

ParSCo (Parasitology Summer Course) is an intense, 1-week-long summer course organized by the Parasitology Unit of the Department of Veterinary Medicine, University of Bari, Italy, with the support of the World Association for the Advancement of Veterinary Parasitology (WAAVP), the European Veterinary Parasitology College (EVPC) and Parasites and Vectors. The course, which is conducted in southern Italy, is planned for parasitologists and post-graduate students working in the field of parasitology. The course consists of theoretical and practical lessons, which include the collection, identification and diagnosis of parasites of pets, livestock and wildlife. The participants in ParSCo are afforded the opportunity to be involved in clinical examination and sample collection for the diagnosis of parasitic diseases (e.g. leishmaniosis, thelaziosis and many tick-borne diseases) present in the Mediterranean Basin. The course is conducted at Casa di Caccia, a hunting lodge situated in the Gallipoli Cognato Forest near the Basento River in the Basilicata region in southern Italy. In addition to the training purpose, ParSCo is a great opportunity for sharing knowledge and expertise while becoming part of the parasitology community in a pleasant environment. In this editorial, we share some information and celebrate 10 years of ParSCo, looking forward to forthcoming sessions of this unique parasitology summer course.

Effects of migratory animals on resident parasite dynamics.

Migratory animals can bring parasites into resident animal (i.e., non-migratory) home ranges (transport effects) and exert trophic effects that either promote or reduce parasite exposure to resident hosts. Here, we examine the importance of these transport and trophic effects and their interactions for resident parasite dynamics. We propose that migrant transport and trophic effects are impacted by the number of migratory animals entering a resident's home range (migration intensity), the amount of time that migrants spend within a resident's home range (migration duration), and the timing of migrant-resident interactions. We then incorporate migration intensity, duration, and timing into a framework for exploring the net impact of migrant trophic and transport effects on resident animal parasite prevalence.

Parasites of Stray Cats in Iran: A Parasitological and Histopathological Study.

Many zoonotic parasitic diseases, including Toxocara cati, may be spread by stray cat populations. This study aimed to determine the prevalence of parasites by performing parasitological and histopathological examinations on stray cats in Shiraz, Iran. A total of 106 stray cats from different geographical areas of Shiraz, southern Iran, were examined for the presence of parasites. The overall prevalence was found to be 83.02% (88/106), and eight parasites were found. The parasites included three genera of cestodes [Joyeuxiella echinorhynoides (52.83%), Taenia taeniaeformis (21.70%), and Dipylidium caninum (1.89%)], three nematodes [Physaloptera praeputialis (23.59%), Toxocara cati (15.09%), and Rictularia sp. (1.89%)], one protozoa [Isospora spp. (6.60%)], and one arthropod [Ctenocephalides felis (5.66%)]. The prevalence did not significantly differ between males and females. It did appear, nevertheless, that the age of cats may be regarded as a risk factor for these parasitic infections. Histopathological examination revealed some parasite-induced lesions in the intestine and stomach, including hyperemia, hemorrhage, mucosal destruction and inflammation. The lung tissues showed some histopathological lesions such as hemorrhage, edema, emphysema and mild inflammation, and dormant larvae were found in one tongue sample. The results of the present study showed that parasitic infections and, more importantly, T. cati are relatively prevalent in stray cats, and the people living in this area are at serious risk of this zoonotic disease. The cats in this region need to be monitored, and specific preventive measures should be developed by public health officials.

Morphological and Molecular Characterization of Two New Species of Ceratomyxa Thélohan, 1892 (Cnidaria: Myxosporea) from the Marine Ornamental Fish Zanclus cornutus (Linnaeus, 1758) off Lakshadweep Islands, Arabian Sea.

PURPOSE: The present study provides the complete morphological and molecular description of two new species of myxosporeans, Ceratomyxa zancli n. sp. and Ceratomyxa cornuti n. sp. infecting the gallbladder of Zanclus cornutus from the Lakshadweep Islands, Arabian Sea. METHODS: Zanclus cornutus were screened for the presence of myxosporeans, and the recovered myxospores were morphologically characterized using Nomarski Differential Interference Contrast (DIC) optics. The sequences of SSU rDNA were employed for molecular and phylogenetic studies. RESULTS: Both the parasites exhibited a prevalence of 21% each. C. zancli n. sp. is characterized by broadly cresentic myxospores with convex anterior and slightly concave to straight posterior margins and rounded ends. Spore valves two, unequal, measured 9.6 ± 0.7 µm × 25.2 ± 1.3 µm. Polar capsules two, unequal, spherical, measured 4 ± 0.6 µm × 3.5 ± 0.6 µm. Polar filament exceptionally long and arranged irregularly. Myxospores of C. cornuti n. sp. are elongated with convex anterior and slightly concave to straight posterior margins. Spore valves two, unequal, measured 7.00 ± 0.4 µm × 26.56 ± 1.8 µm. Polar capsules spherical, unequal, measured 3.52 ± 0.2 × 3.36 ± 0.35. Molecular analysis of C. zancli n. sp. (ON818297) and C. cornuti n. sp. (ON818298) resulted in 1469 and 1491 bp long SSU rDNA sequences, respectively. Molecularly C. zancli n. sp. is close to C. diplodae and C. barnesi with 91.39% similarity, while C. cornuti n. sp. appears closer to C. robertsthomsoni with 97.46% similarity. In phylogenetic analyses, C. zancli n. sp. branched separately within the Ceratomyxa clade while C. cornuti n. sp. clustered with C. robertsthomsoni and C. thalassomae. CONCLUSION: Based on the differences in morphological, morphometric, molecular, and phylogenetic characteristics, as well as differences in the host and geographic location, the above two species of myxosporeans are considered novel. The study forms the first report of a species of Ceratomyxa from Z. cornutus.

Scoliosis and kyphosis in blue-spotted and marbled flathead fish associated with a Myxobolus acanthogobii-like parasite.

Spinal deformities in finfish have the potential to impact aquaculture industries and wild populations by increasing morbidity, mortality, and reducing growth rates. Myxobolus acanthogobii has been implicated in causing scoliosis and lordosis in various aquatic species in Japan. We investigated 4 cases of spinal deformity in 2 flathead (Platycephalus) species that were submitted to the Elizabeth Macarthur Agricultural Institute (EMAI) in New South Wales (NSW), Australia, between 2015 and 2021. Flathead are commercially significant species that are popular among Australian consumers, and are also sought-after species targeted by recreational fishers. Gross deformities are concerning to the community and may impact the quality and quantity of specimens available for consumption. Three blue-spotted flathead (P. caeruleopunctatus) and one marbled flathead (P. marmoratus) were submitted, all with marked scoliosis and kyphosis; 1-2-mm cysts were present on the dorsum of the brain, most often over the optic lobe or cerebellum. Cytology and differential interference microscopy of cyst material revealed numerous oval spores, x̄ 14 ± SD 0.75 µm × x̄ 11.5 ± SD 0.70 µm, with 2 pyriform polar capsules, the morphology of which is consistent with a Myxobolus sp. PCR assay and 18S rDNA sequencing of the cyst material identified a Myxobolus sp. with 96% identity to M. acanthogobii. The identification of this Myxobolus sp. confirms the presence of parasites with the potential to cause spinal deformity in significant aquatic species in NSW waterways.