Fish Immune Responses to Myxozoa

Sitjà‐Bobadilla, Ariadna; Schmidt‐Posthaus, Heike; Wahli, Thomas; Holland, Jeremy; Secombes, Chris J.

doi:10.1007/978-3-319-14753-6_14

Cited by 32 publications

(46 citation statements)

References 174 publications

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“…Myxozoans are among the most abundant parasites in nature. There are approximately 2,000–2,500 species (Paladini, Longshaw, Gustinelli, & Shinn, ) and the histozoic myxozoans make for most dangerous form of infection (Gomez et al., ), causing outbreaks of mortality in fish (Gomez et al., ; Lom & Dyková, ; Sitjà‐Bobadilla, Schmidt‐Posthaus, Wahli, Holland, & Secombes, ). Detailed information on species of myxozoans infecting mullets was published by Bahri and collaborators (Bahri, Andree, & Hedrick, ; Bahri & Marques, ) and recently reviewed by Ovcharenko ().…”

Section: Discussionmentioning

confidence: 99%

“…(a) Spindle-like plasmodia developing in the muscle layer (arrow heads) and in submucosal layer (arrows), scale bar = 100 lm; (b) plasmodium (asterisk) encysted in submucosal layer, several mast cells (arrows) are in close vicinity to the plasmodium, scale bar = 20 lm; (c) micrograph shows intestinal epithelium of L. saliens, numerous free spores of M. mugchelo are in proximity to mucous cells (circles), some mast cells (arrows) are visible within the epithelium, scale bar = 10 lm; (d) free spores in epithelium and in connective tissue in close vicinity to the mast cells (circles), intense degranulation of the mast cells (arrows) is evident, scale bar = 10 lm 4 | DISCUSSION Myxozoans are among the most abundant parasites in nature. Thereare approximately 2,000-2,500 species(Paladini, Longshaw, Gustinelli, & Shinn, 2017) and the histozoic myxozoans make for most dangerous form of infection(Gomez et al, 2014), causing outbreaks of mortality in fish(Gomez et al, 2014;Lom & Dykov a, 2006;Sitj a- Bobadilla, Schmidt-Posthaus, Wahli, Holland, & Secombes, 2015).…”

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

Dezfuli

Castaldelli

Giari

2017

Journal of Fish Diseases

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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.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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

Dezfuli

Castaldelli

Giari

2017

Journal of Fish Diseases

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“…It appears that trophic transmission followed by migration of the parasites to the gall bladder via the common bile duct represents a likely pathway of acquisition of the new host. The bile is considered an immunologically privileged site where the hosts' immune system has reduced surveillance capability [61] and hence represents a close-by protective niche on ingestion, where the parasite was able to survive despite the advanced immune system capabilities of vertebrates which can mount parasite-specific adaptive responses [62]. Thereby survival in a new host group is considered favorable [63,64] and compensates the initial costs related to generalism [65].…”

Section: Discussionmentioning

confidence: 99%

Mechanisms and Drivers for the Establishment of Life Cycle Complexity in Myxozoan Parasites

Lisnerová

Fiala

Cantatore

et al. 2020

Biology

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It is assumed that complex life cycles in cnidarian parasites belonging to the Myxozoa result from incorporation of vertebrates into simple life cycles exploiting aquatic invertebrates. However, nothing is known about the driving forces and implementation of this event, though it fostered massive diversification. We performed a comprehensive search for myxozoans in evolutionary ancient fishes (Chondrichthyes), and more than doubled existing 18S rDNA sequence data, discovering seven independent phylogenetic lineages. We performed cophylogenetic and character mapping methods in the largest monophyletic dataset and demonstrate that host and parasite phylogenies are strongly correlated, and that tectonic changes may explain phylogeographic clustering in recent skates and softnose skates, in the Atlantic. The most basal lineages of myxozoans inhabit the bile of chondrichthyans, an immunologically privileged site and protective niche, easily accessible from the gut via the bile duct. We hypothesize that feed-integration is a likely mechanism of host acquisition, an idea supported by feeding habits of chimaeras and ancient sharks and by multiple entries of different parasite lineages from invertebrates into the new host group. We provide exciting first insights into the early evolutionary history of ancient metazoan parasites in a host group that embodies more evolutionary distinctiveness than most other vertebrates.

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“…Myxozoans are thought to express different antigenic profiles as a result of adaptation to different hosts and environments across their developmental timeline. This may offer some explanation as to why the development of effective myxozoan vaccines has been elusive (Sitjà‐Bobadilla, Schmidt‐Posthaus, Wahli, Holland, & Secombes, 2015). Employing these techniques across multiple stages of sporogenesis could shed light on the structural and compositional variation associated with myxozoan development.…”

Section: Discussionmentioning

confidence: 99%

Insights into myxozoan composition and physiology revealed by histochemical properties of myxospores

Stilwell

Griffin

Rosser

et al. 2020

Journal of Fish Diseases

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Myxozoa (phylum Cnidaria) are a diverse group of metazoan parasites that predominately infect fish. Little is known regarding the composition and physiology of their myxospore life stage. The objective of this work was to investigate the composition of myxospores and extrasporogonic stages of nine myxozoan species infecting various teleost fish using histochemical staining techniques. Thirty histochemical stains were applied to formalin‐fixed, paraffin‐embedded tissues processed routinely for light microscopic evaluation. The polar capsules were the most consistent stain target across the taxa examined. Polar capsule staining with Alizarin red, von Kossa and methyl green‐pyronin suggests the presence of intracapsular calcium and phosphate, which may contribute to polar filament discharge or pathogenesis of host invasion. The shell valves and suture lines of most myxozoans were stained with Luna and phosphotungstic acid haematoxylin stains, consistent with the presence of chitin and microfibrils, respectively. Vacuoles were consistently highlighted by diastase‐susceptible periodic acid‐Schiff and Grocott's methenamine silver staining, indicating glycogen. Other histochemical stains exhibited inconsistent staining across the taxa, suggesting differences in myxospore composition potentially reflective of physiologic variations and tissue tropisms. This work provides some information on conserved features and taxa‐associated composition of myxospores and lends insight into myxozoan physiology and host–parasite interactions.

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Fish Immune Responses to Myxozoa

Cited by 32 publications

References 174 publications

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

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

Mechanisms and Drivers for the Establishment of Life Cycle Complexity in Myxozoan Parasites

Insights into myxozoan composition and physiology revealed by histochemical properties of myxospores

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