Mechanisms of the host immune response and helminth-induced pathology during Trichobilharzia regenti (Schistosomatidae) neuroinvasion in mice.

Helminth neuroinfections represent serious medical conditions, but the diversity of the host-parasite interplay within the nervous tissue often remains poorly understood, partially due to the lack of laboratory models. Here, we investigated the neuroinvasion of the mouse spinal cord by Trichobilharzia regenti (Schistosomatidae). Active migration of T. regenti schistosomula through the mouse spinal cord induced motor deficits in hindlimbs but did not affect the general locomotion or working memory. Histological examination of the infected spinal cord revealed eosinophilic meningomyelitis with eosinophil-rich infiltrates entrapping the schistosomula. Flow cytometry and transcriptomic analysis of the spinal cord confirmed massive activation of the host immune response. Of note, we recorded striking upregulation of the major histocompatibility complex II pathway and M2-associated markers, such as arginase or chitinase-like 3. Arginase also dominated the proteins found in the microdissected tissue from the close vicinity of the migrating schistosomula, which unselectively fed on the host nervous tissue. Next, we evaluated the pathological sequelae of T. regenti neuroinvasion. While no demyelination or blood-brain barrier alterations were noticed, our transcriptomic data revealed a remarkable disruption of neurophysiological functions not yet recorded in helminth neuroinfections. We also detected DNA fragmentation at the host-schistosomulum interface, but schistosomula antigens did not affect the viability of neurons and glial cells in vitro. Collectively, altered locomotion, significant disruption of neurophysiological functions, and strong M2 polarization were the most prominent features of T. regenti neuroinvasion, making it a promising candidate for further neuroinfection research. Indeed, understanding the diversity of pathogen-related neuroinflammatory processes is a prerequisite for developing better protective measures, treatment strategies, and diagnostic tools.

Characterization of digenetic trematodes infecting African catfish (Clarias gariepinus) based on integrated morphological, molecular, histopathological, and immunological examination.

Parasitic infection may cause massive losses in Clarias gariepinus fries and fingerlings. Therefore, this study aimed to characterize the digenetic trematodes species (two adults' flukes and one metacercariae) infecting African catfish Clarias gariepinus, as well as their histopathological impacts on infected fish. The intestinal flukes were identified as Orientocreadium batrachoides and Masenia bangweulensis based on their morphological and molecular characteristics. Sequencing of their 28S (LSU rRNA) and 18S rRNA (SSU rRNA) genes confirmed that these trematodes belong to the families Orientocreadiidae and Cephalogonimidae, respectively. The metacercariae trematode infecting skin and muscles were only morphologically identified as Cyanodiplostomum sp. The gene expression levels of MHC II increased in naturally infected fish either with O. batrachoides or Cyanodiplostomum sp. alone, compared with uninfected catfish. In addition, lysozyme levels in individual fish serum increased in catfish infected either with O. batrachoides or Cyanodiplostomum sp. alone. Histopathological examination of the skin revealed embedded parasitic cysts that displaced tissue in the dermis. Surrounding tissues were infiltrated with melanomacrophages and displayed dermal edema. Histopathological analysis showed O. batrachoides or M. bangweulensis between the gastric folds of the stomach of infected catfish, causing infiltration of mononuclear inflammatory cells in the lamina propria.

Morphological and molecular differentiation of Diplostomum spp. metacercariae from brain of minnows (Phoxinus phoxinus L.) in four populations of northern Europe and East Asia.

Metacercariae of trematodes from the genus Diplostomum are major helminth pathogens of freshwater fish, infecting the eye or the brain. The taxonomy of the genus Diplostomum is complicated, and has recently been based mainly on the molecular markers. In this study, we report the results of the morphological and molecular genetic analysis of diplostomid metacercaria from the brain of the minnow Phoxinus phoxinus from three populations in Fennoscandia (Northern Europe) and one population in Mongolia (East Asia). We obtained the data on the polymorphism of the partial mitochondrial cox1 gene and ribosomal ITS1-5.8S-ITS2 region of these parasites. РСА-based morphological analysis revealed that the parasites in the Asian and the European groups of Diplostomum sp. were distinctly different. Metacercariae from the brain of Mongolian minnows were much larger than those from the brain of Fennoscandian minnows but had much fewer excretory granules. Considering that the two study regions were separated by a distance of about 4500 km, we also tested the genetic homogeneity of their host, the minnow, using the mitochondrial cytb gene. It was shown that Diplostomum-infected minnows from Mongolia and Fennoscandia represented two previously unknown separate phylogenetic lineages of the genus Phoxinus. Both molecular and morphological analysis demonstrated that the parasites from Fennoscandia belonged the species Diplostomum phoxini, while the parasites from Mongolia belonged to a separate species, Diplostomum sp. MТ.Each of the two studied Diplostomum spp. was associated with a specific, and previously unknown, genealogical lineage of its second intermediate host, P. phoxinus.

Renicolidae infection in Manx shearwater (Puffinus puffinus): is parasitism implicated on renal lesions?

Renicolid digeneans are frequently observed in the renal tubules and ureters of seabirds, such Puffinus puffinus, a migratory species distributed along the Brazilian coast. However, few studies have focused on the relationship between renicolid infection and health status in P. puffinus. Thus, the aim of this study was to describe (i) renal and systemic alterations, (ii) the renicolids and (iii) the biological aspects associated with the presence of renicolids in P. puffinus. Gross and histological assays were performed in 93 P. puffinus stranded on the Paraná coast, southern Brazil, and renicolids were submitted to morphological and molecular assays. A high prevalence of renicolids in P. puffinus (71/93) was observed. In the kidney, the main microscopic findings were lymphocytic interstitial infiltrate, ductal ectasia and tubular necrosis. The renal lesions were significantly associated with the parasite infection. The morphological (n = 84) and molecular analyses (n = 2) confirmed the species as Renicola sloanei (100% and 95.9% of nucleotide identity with R. sloanei strains from P. puffinus and from Spheniscus demersus, respectively). In both parasitized and non-parasitized animals, cardiac and skeletal muscle degeneration and necrosis were the most frequent systemic changes. Therefore, the results suggest renicolids being a possible cause for the demonstrated renal alterations. A contribution of this parasite to a decreased health status of Puffinus puffinus along their migratory route is possible.

Anatomopathological lesions of infection caused by Platynosomum illiciens (Braun, 1901) in Neotropical primates kept in captivity.

This study described the hepatobiliary anatomopathological lesions associated with trematode Platynosomum illiciens parasitism in Neotropical primates kept in captivity. In the evaluated organs, we observed portal fibrosis, biliary epithelial hyperplasia, and inflammatory reaction with a predominance of lymphocytes and plasmocytes, and in some cases infiltration of eosinophils and neutrophils.

Pathology associated with three new Clinostomum metacercariae from Argentina with morphological and DNA barcode identification.

In the Laboratory of Parasites of Fishes, Crustaceans and Mollusks (CEPAVE), we undertook a parasitological study on three species of fish from the Espinal and Esteros del Iberá ecoregions of Argentina. Clinostomid metacercariae were found parasitizing Characidium rachovii, Crenicichla vittata and Gymnogeophagus balzanii. In this study, we analysed the damage that these parasites inflict on their hosts through the evaluation of histological sections. In addition, Clinostomum metacercariae were identified using morphological characters and DNA barcoding. In the pathological analysis, we observed that muscle tissue was the most affected. The inflammatory response showed vascular congestion areas and infiltration of numerous inflammatory cells, mainly lymphocytes. The molecular and morphological approach supports the presence of three new lineages of clinostomid metacercariae in Argentina. This could lead to the discovery of a high number of lineages or species of Clinostomum from South America.

Pathological effects of Cichlidogyrus philander Douëllou, 1993 (Monogenea, Ancyrocephalidae) on the gills of Pseudocrenilabrus philander (Weber, 1897) (Cichlidae).

Histopathological changes of Cichlidogyrus philander Douëllou, 1993 on the gills of Pseudocrenilabrus philander (Weber, 1897) were studied using light and scanning electron microscopy. Observations revealed that C. philander attaches to its host by alternating the prohaptor (for temporary attachment or feeding) or haptor (using haptoral parts for firm and secured attachment). The sharp terminal ends of the anchors are inserted basally into the gill lamella, between two adjacent secondary gill lamellae and the marginal hooklets assist by superficially penetrating, holding and lifting epithelial tissue in the proximal region of the secondary gill lamella. The attachment of C. philander resulted in compression, rupturing of the interlamellar epithelium, change in the organization of epithelial cells in both primary and secondary gill lamella, displacement of the extracellular cartilaginous matrix, occasional rupturing of blood vessels and erythrocytes and some cells becoming ill-defined. At the site of attachment, the host response comprises of hyperplasia, increase in the number of mucous cells and infiltration with neutrophils. It was concluded that the effect of C. philander is mild in natural conditions.

Histopathological changes induced by the digenean intestinal parasite Masenia nkomatiensis Dumbo, Dos Santos, & Avenant-Oldewage, 2019 of the catfish Clarias gariepinus (Burchell) from Incomati Basin, Mozambique.

The intestines of 154 Clarias gariepinus were examined of which 29 were naturally infected with Masenia nkomatiensis, and of these, seven (intensity ranging from 8 to 231) were examined for pathology. Destruction of the epithelium covering the villi, detachment of epithelial cells and parts of villi were observed. Excessive mucus secretion occurred in the vicinity of the worm and catarrh was observed, indicative of an inflammatory response. The number of mucous and mast cells was higher at the attachment site than at an area 5,000 µm away and in uninfected individuals, suggesting that the parasite triggered a localized innate immune response. The number of neutrophils, basophils and lymphocytes in infected tissue was not significantly different from uninfected tissue confirming that no acquired immune response was produced against the maseniid. The caecae in the anterior part of the parasites' intestine consisted of convoluted epithelium forming invaginations or "crypts." Contraction of the thick layer of circular muscle fibres of the caeca facilitates the movement of digested material. Observation of digested host cells and cell debris within the caecae provides further evidence that M. nkomatiensis is consuming host cells.

Multiple food-borne trematodiases with profound systemic involvement: a case report and literature review.

BACKGROUND: Food-borne trematodiases are an important group of neglected global diseases. Affected patients in regions with low prevalence usually experience delayed diagnosis, especially when presenting with atypical clinical symptoms. Here, we presented a rare case of a Chinese patient infected with three food-borne trematodiases. CASE PRESENTATION: A 42-year-old man presented with diarrhea, lower extremity edema, and symptoms of cardiac dysfunction. He had a history of intermittent consumption of raw freshwater fishes for 6-7 years. Upon evaluation, he had eosinophilia, anemia, intrahepatic bile duct dilatation and a growing space-occupying lesion in the left atrium. The patient underwent a cardiac surgery which revealed an endocardial hematoma due to mechanical injuries. Imaging investigations also revealed intracranial and pulmonary lesions. A total of three trematodiases were diagnosed based upon microscopic stool examination, from which eggs of Clonorchis sinensis, Heterophyidae and Echinostomatidae were identified. Deposition of Clonorchis sinensis eggs was also observed from ileocecal squash slides. The patient was successfully treated with three cycles of praziquantel. CONCLUSIONS: Food-borne trematodiases may present with systemic involvement. Patients with dietary history of high risk or atypical ingestions should be evaluated for parasitic infection, even in non-endemic areas.

A Case of Unexpected Clinostomum complanatum Infection Initially Presenting as Foreign Body in Pharynx.

A 46-year old man visited our outpatient clinic with complaint of foreign body sensation in throat after consuming raw freshwater fish 5 days ago. Laryngoscopic examination revealed a motile worm attached on posterior pharyngeal wall. The worm was removed using biopsy forceps under transnasal endoscopy and evidently identified as Clinostomum complanatum after microscopic examination. Patient's subjective foreign body sensation of throat and hyperemia of laryngeal mucosa remained for approximately 2 weeks post-removal, which were eventually resolved after administration of non-steroidal anti-inflammatory drug and anti-refluxant drug for 2 weeks. Treatment was ended at three weeks since the first visit. C. complanatum infections in humans are rare, and only four cases have been reported in Korea. Symptoms resembling pharyngitis or laryngitis occurs by consumption of raw, infected freshwater fish and treatment is done by mechanically removing the parasite.

Necrotizing Enteritis Caused by Pharyngostomum cordatum Infection in a Stray Cat.

A stray female cat of unknown age, presenting bright red watery diarrhea, was submitted to the Animal and Plant Quarantine Agency for diagnosis. In the small intestines extracted from the necropsied cat, numerous white oval-shaped organisms were firmly embedded in the mucosa and there was thickening of intestinal wall. Histopathological analysis revealed severe necrotizing enteritis, together with atrophied intestinal villi, exfoliated enterocytes, and parasitic worms. Recovered worms were identified as Pharyngostomum cordatum by morphological observation and genetic analysis. Although P. cordatum is known to occur widely in Korea, this is the first clinical description of an infection by P. cordatum causing severe feline enteritis.

Fascioloides magna in Moose ( Alces alces) From Elk Island National Park, Alberta.

Thirty-seven adult female moose ( Alces alces) from 2 distinct but adjacent populations in Elk Island National Park (EINP), Alberta, Canada (19 in north EINP and 18 in south EINP), were fitted with mortality-sensing VHF radio-collars, and radio signals were acquired daily to ascertain mortality status. At capture, serum, whole blood, and feces were collected; pregnancy was determined; teeth were aged by visual inspection; and a portion of liver was assessed by ultrasound examination. Postmortem examination was conducted on 20 suitable carcasses. Clinical pathological abnormalities, including eosinophilia, polycythemia, elevated levels of liver enzymes in serum, hemoglobin, hematocrit, and red blood cell distribution, and liver damage as seen in ultrasound images occurred only in moose from north EINP. Infected moose had 4.7 ± 4.8 Fascioloides magna flukes per liver (mean ± SD). The proportion of moose pregnant at capture was similar in both populations (74% in north EINP, 61% in south EINP). Proportional mortality was significantly higher in moose from the north (68%) than the south (32%). Fascioloides magna was associated as a cause of death in 7 of 14 (50%) moose in the north where cause of death was determined, while predation ( n = 1), acute toxemic syndrome ( n = 3), dystocia ( n = 1), and roadkill and undetermined causes ( n = 3) were additional causes of mortality. F. magna was associated with poor body condition and was a major cause of mortality in north EINP but not south EINP, despite very similar habitat and proximity, suggesting a significant role for these flukes in affecting health and viability of naturally infected moose populations.

Prominent hepatic ductular reaction induced by Oschmarinella macrorchis in a Hubbs' beaked whale Mesoplodon carlhubbsi, with biological notes.

Beaked whales are among the least known group of cetaceans, and information regarding their pathology and parasitology is especially scarce. We describe a case of significant parasitism by a trematode found in the liver of an adult male Hubbs' beaked whale Mesoplodon carlhubbsi that stranded in Hokkaido, Japan. Post-mortem examinations revealed a localised area of discolouration restricted to the hilar region of the left hepatic lobe, where spindle-shaped trematodes occupied the dilated and hypertrophic bile ducts. Histologically, the intrahepatic bile ducts were characterised by adenomatous hyperplasia with goblet cell metaplasia of the biliary epithelium. Findings in the adjacent hepatic parenchyma included pseudocarcinomatous ductular reactions obliterating hepatocytes, a histomorphology not previously reported in marine mammals. Morphological identification of the trematode corresponded to Oschmarinella macrorchis, which has only been reported once in a Stejneger's beaked whale, M. stejnegeri. PCR amplification and sequencing analyses of the parasite's mtDNA ND3, 18S and 28S rRNA regions generated novel gene sequences. Environmental contaminant levels were measured to explore its potential relationship with the parasitism but there was no conclusive association. A high level of polychlorinated biphenyl (30000 ng g-1 lipid weight) was detected in the blubber of this individual, when compared to those of 3 other male Hubbs' beaked whales stranded in Japan. Stomach contents were also analysed, indicating the presence of various squid species and unidentified fish. Our results contribute to the knowledge of a little-known beaked whale and provide evidence for the first time of the pathobiological response caused by O. macrorchis.

Chronic Cystitis Associated with Plesiochorus cymbiformis ( Rudolphi, 1819 ) Looss, 1901 (Digenea: Gorgoderidae) in a Loggerhead Turtle Caretta caretta (Linnaeus 1758) (Testudines, Cheloniidae) from Brazil: A Case Report.

This paper reports the first occurrence of Plesiochorus cymbiformis (Digenea: Gorgoderidae) in a loggerhead turtle ( Caretta caretta [Testudines, Cheloniidae]) in Brazil and describes the histological findings of related injuries to the urinary bladder.

Pathological and molecular studies of the renal trematode Paratanaisia bragai in Indian peafowls (Pavo cristatus).

Endoparasitic diseases are commonly encountered in free-ranging birds. Although not all endoparasites cause disease, persistent infection with large numbers of parasites almost always affects normal physiological functions, leading to deleterious effects on the host. This paper describes the anatomopathological alterations caused by the renal trematode Paratanaisia bragai in Indian peafowl (n = 3) and examines the phylogeny of these and related parasites. Peafowl from forests in and around the Bareilly region, Uttar Pradesh, India, were necropsied, and microscopic and molecular investigations were performed. The peafowl were confirmed to be infected with P. bragai. Significant gross pathological lesions suggested nephrosis, and microscopic findings indicated a mild-to-moderate degree of nephrosis caused by the parasites in the tissue. The parasites were identified as P. bragai by histomorphological analysis of adult and eggs in the ureters, and the identification was confirmed by PCR and phylogenetic analysis. Nucleotide sequencing of the PCR products from the renal trematodes recovered from Indian peafowl revealed a close association with P. bragai from Columbiformes in the United Kingdom and Spain. The pathology and molecular epidemiology of parasitic diseases affecting peafowl is not well understood in India. This is the first report from India and the second report worldwide to document P. bragai infection in peafowl.

Histopathological and ultrastructural assessment of two mugilid species infected with myxozoans and helminths.

The histopathology and ultrastructure of the intestine of mullets, Liza ramada and Liza saliens, from Comacchio lagoons (northern Italy) naturally infected with myxozoans and helminths were investigated and described. Sixty-two (80.5%) of 77 mullets harboured one or more of the following parasites species: Myxobolus mugchelo (Myxozoa), Neoechinorhynchus agilis (Acanthocephala), Haplosplanchnus pachysomus and Dicrogaster contractus (Digenea). Co-occurrence of helminths with myxozoans was common. The main damage caused by digeneans was destruction of the mucosal epithelium of the villi, necrosis and degeneration of intestinal epithelial cells. More severe intestinal damage was caused by acanthocephalans which reach the submucosa layer with their proboscis. At the site of helminths infection, several mast cells (MCs), rodlet cells (RCs), mucous cells and few neutrophils and macrophages were observed in the epithelium. RCs and mucous cells exhibited discharge activity in close vicinity to the worm's tegument. M. mugchelo conspicuous plasmodia were encysted mainly in muscle and submucosa layers of the intestine. Indeed, spores of M. mugchelo were documented within the epithelial cells of host intestine and in proximity to MCs. Degranulation of the MCs near the myxozoans was very frequent.

Moderate pathogenic effect of Ligophorus uruguayense (Monogenoidea, Ancyrocephalidae) in juvenile mullet Mugil liza (Actinopterygii, Mugilidae) from Brazil

ABSTRACT Monogenoidea pathogenic activity can elicit various histological responses in fish. Species of Ligophorus are specific parasites of mullets, and its relationship with host fish may result in a moderate pathogenic action. In order to ascertain this relationship, estuarine mullets (Mugil liza) were collected in an estuary, reared in laboratory, for three weeks, and forwarded for histological and parasitological analyses. Ligophorus uruguayense (Monogenoidea) infestation in the gills of the mullets was identified. The severe infestation by only one species of Monogenoidea may result from the specificity of these parasites to mullets. Mullets submitted to histological analysis exhibited respiratory epithelium detachment; mild, moderate and severe hyperplasia of the respiratory epithelium; atrophy; and telangiectasia of the gills. This is the first study reporting that mullets highly infested by Monogenoidea can show mild (100%) to severe (20%) gill changes with a distinct frequency of occurrence. Because of the high prevalence of mild alterations observed, it is possible to accept that L. uruguayense is moderately pathogenic to M. liza, even during high prevalence and intensity of infestation, as a result of its specificity.