myxozoa

A synopsis of Ortholinea Shulman, 1962 (Cnidaria: Myxosporea: Ortholineidae) is presented and identifies 26 nominal species presently allocated within this genus. Species morphological and morphometric features, tissue tropism, type-host, and type-locality are provided from original descriptions. Data from subsequent redescriptions and reports is also given. Accession numbers to sequences deposited in GenBank are indicated when available, and the myxospores were redrawn based on original descriptions. The information gathered shows that Ortholinea infect a wide taxonomic variety of freshwater and marine fish...

BACKGROUND: Myxozoa is a class of cnidarian parasites that encompasses over 2,400 species. Phylogenetic relationships among myxozoans remain highly debated, owing to both a lack of informative morphological characters and a shortage of molecular markers. Mitochondrial (mt) genomes are a common marker in phylogeny and biogeography. However, only five complete myxozoan mt genomes have been sequenced: four belonging to two closely related genera, Enteromyxum and Kudoa, and one from the genus Myxobolus...

Two previously undescribed myxozoan species, Henneguya sardellae sp. n. and H. margaritae sp. n., found infecting connective tissues of the Neotropical characid fish Oligosarcus jenynsii (Günther) from Argentina are morphologically and molecularly characterised. Mature spores of H. sardellae sp. n. are ellipsoid, with two, straight and visibly fused caudal appendages cleaved at its blunt terminal end; measuring 33.5 ± 1.2 (30.9-35.5) μm in total length, spore body 17.5 ± 0.6 (16.3-18.6) µm, 7...

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RNA interference (RNAi) is an effective approach to suppress gene expression and monitor gene regulation. Despite its wide application, its use is limited in certain taxonomic groups, including cnidarians. Myxozoans are a unique group of cnidarian parasites that diverged from their free-living ancestors about 600 million years ago, with several species causing acute disease in farmed and wild fish populations. In this pioneering study we successfully applied RNAi in blood stages of the myxozoan Sphaerospora molnari, combining a dsRNA soaking approach, real-time PCR, confocal microscopy, and Western blotting...

OBJECTIVE: During routine histological examination of tissues from mortality events of anadromous Brook Trout Salvelinus fontinalis from Prince Edward Island (PEI), Canada, myxospores consistent with Myxobolus were observed infecting the central nervous system. The objective of this study was to identify the species of Myxobolus infecting the nervous system of anadromous Brook Trout from PEI, Canada. METHODS: Myxospore morphology, small subunit (SSU) ribosomal DNA (rDNA) sequence data, and histology were used to identify myxospores isolated from infected Brook Trout...

The purple-spotted bigeye, Priacanthus tayenus, is a marine benthic fish native to the Indian and Pacific Oceans, including the Arabian Gulf in Saudi Arabia. This study identified a myxozoan parasite infecting wild P. tayenus from the Saudi Arabian Gulf. These parasites produced spherical to ovoid-shaped, white plasmodia enclosed within pseudocysts in the fish musculature. The annual infection rate was 5.1%, with the highest prevalence in summer (7.6%), followed by spring (6%), and autumn (2.5%), while no infections were observed in winter...

We describe a new kudoid species, Kudoa tanakai n. sp., in the scalpel sawfish, Prionurus scalprum (Actinopterygii: Acanthuriformes: Acanthuridae), from the natural water around western Japan. The plasmodia were filamentous, localized in pseudocysts in the myofibers of the trunk muscles. The occurrence of plasmodia in the trunk muscle showed no site preference. Its myxospores were spheroid, measuring 6.6-7.6 (7.0) µm by 5.8-6.9 (6.3) µm in apical view (width) and 5.7-6.6 (6.2) in length (n = 30), with four shell valves and a corresponding number of spheroid polar capsules...

Small pelagic fishes represent one of the most important food resources off the Northwest coast of Africa. Despite their economic significance, little is known about the infections with flesh invading myxosporean parasites of genus Kudoa (Cnidaria, Myxozoa). Heavy infections in the flesh may be associated with post-mortem myoliquefaction, commonly known as 'soft flesh'. This condition may reduce the quality and marketability of the fish fillet, resulting in both economic losses to the fishing industry and loss of consumer confidence...

Salmonids are affected by the economically significant whirling disease (WD) caused by the myxozoan parasite Myxobolus cerebralis . In the past, it was endemic to Eurasia, but it has now spread to different regions of North America, Europe, New Zealand, and South Africa. Among salmonids, rainbow trout is considered the most highly susceptible host. Upon entering to the host's body, the parasite invades the spine and cranium, resulting in whirling behaviour, a blackened tail, and destruction of cartilage. The disease is characterized by the infiltration of numerous inflammatory cells, primarily lymphocytes and macrophages, with the onset of fibrous tissue infiltration...

Three new aurantiactinomyxon types are described from the oligochaete Ilyodrilus templetoni (Southern, 1909) (Naididae) collected from a northern Portuguese estuary, based on light microscopy and sequencing of the 18S rDNA. The addition of I. templetoni to the group of freshwater annelids known to be permissive for aurantiactinomyxon development reinforces the crucial role of naidids in the evolution and settlement of myxozoans in estuarine environments. Maximum likelihood and Bayesian inference analyses of a comprehensive 18S rDNA dataset placed the novel types within the Paramyxidium clade...

A new Myxobolus species, Myxobolus nekrasovi n. sp., was found in the gill arch of the gibel carp Carassius auratus gibelio during investigation of fish myxosporean fauna of ponds of Lake Baikal basin. The parasites were studied on the basis of spore morphology, as well as with histological and molecular methods. Mature spores of M. nekrasovi n. sp. are ellipsoidal in frontal view and lemon-shaped in lateral view, measuring 13.84 ± 0.4 (12.2-15) μm in length, 9.73 ± 0...

OBJECTIVE: Proliferative gill disease (PGD) in Channel Catfish Ictalurus punctatus and hybrid catfish (Channel Catfish × Blue Catfish I. furcatus) is attributed to the myxozoan Henneguya ictaluri. Despite evidence of decreased H. ictaluri transmission and impaired parasite development in hybrid catfish, PGD still occurs in hybrid production systems. Previous metagenomic assessments of clinical PGD cases revealed numerous myxozoans within affected gill tissues in addition to H. ictaluri...

During an investigation of Myxobolus diversity in the Chinese longsnout catfish Tachysurus dumerili (Bleeker), a new species infecting the intracranial epidermis of the host was discovered. Upon opening the cranial cavity, several round whitish plasmodia measuring 0.55-0.80 mm in diameter were observed. Fresh spores (n= 50) were pyriform in the frontal view and fusiform in the sutural view, with a length of 15.4±0.6 (13.9-16.5) μm, width of 9.1±0.4 (8.3-9.8) μm, and thickness of 7.0±0...

The present study describes Coccomyxa bragantinensis n. sp., which was found parasitising the gallbladder of the Coco Sea catfish, Bagre bagre, captured off Ajuruteua beach, in the region of Bragança in Pará state, northern Brazil. Most (77.5%) of the 40 fish specimens examined (31/40) had myxospores floating in the bile liquid. These spores are partially ellipsoid, with a tapering anterior extremity and a rounded, elongated posterior extremity with a single piriform polar capsule containing a helicoidal polar filament, with 5-6 coils...

The global cultivation of common carp Cyprinus carpio is developed primarily for either food or recreational purposes and myxosporean infections causing significant economic losses are regularly troublesome for carp farmers. However, most myxosporean species are poorly characterized, making it difficult to correctly elaborate on their parasitism mode and determine pathogenicity. Here, based on an integrative approach, we supplemented fundamental information on three Myxobolus species infecting different carp lineages in China...

OBJECTIVE: Myxosporidiosis of bagrid fishes has been a focus of aquaculture research in recent years. The purpose of this study is to characterize a novel myxobolid, named Myxobolus xiushanensis n. sp., infecting Yellowhead Catfish Tachysurus fulvidraco in China. METHODS: We used molecular biology, morphology, phylogeny, and histopathology in the present study. RESULT: Mature myxospores were circular to ellipsoidal in valve view, measuring 12...

The introduction of new fish species to the aquaculture industry is essential to halt the progressive decline of natural fish stocks. The sheepshead Archosargus probatocephalus is a commercially valuable sparid fish with potential for breeding in captivity, but with limited information regarding parasitic infections that could pose a significant threat for its sustainable production. Thus, the present study aimed to study the myxozoan diversity infecting A. probatocephalus. A novel Henneguya sp. was detected forming plasmodia in the gill lamellae of specimens inhabiting the Brazilian coast, and is characterized based on morphological, histopathological, ultrastructural, molecular, and phylogenetic data...

Myxozoa is a unique group of obligate endoparasites in the phylum Cnidaria that can cause emerging diseases in wild and cultured fish populations. Recently, we identified a new myxozoan species, Myxobolus bejeranoi , which infects the gills of cultured tilapia while suppressing host immunity. To uncover the molecular mechanisms underlying this successful parasitic strategy, we conducted transcriptomics analysis of M. bejeranoi throughout the infection. Our results show that histones, which are essential for accelerated cell division, are highly expressed even one day after invasion...

PURPOSE: The motive of the present study was to investigate incidences of myxozoan parasite infection in commercially important fishes and their characterization using morphological attributes and molecular approach. METHODS: The specimens of cultured Cirrhinus mrigala were sampled and various organs were examined. The plasmodia were detected on the scales. The identification of species was based on the myxospore morphology and 18S rDNA sequence analyses. For phylogenetic analysis, maximum likelihood (ML) and Bayesian inference (BI) methods were employed...