Present knowledge on the life cycle, taxonomy, pathology, and therapy of some Myxosporea spp. important for freshwater fish

El‐Matbouli, Mansour; Fischer-Scherl, T.; Hoffmann, Rudolf

doi:10.1016/0959-8030(92)90071-5

Cited by 113 publications

(86 citation statements)

References 44 publications

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“…Despite many recent advances in our understanding of the life cycle of myxosporeans (Kent et al 2001), most notably that some species have a 2-host life cycle with a myxosporean stage in the fish host and an actinosporean stage in an invertebrate host, the life cycle is not known for any species of Kudoa (El-Matbouli et al 1992, Lom & Dyková 1992, Kent et al 2001. Recently, Moran et al (1999c) determined that K. thyrsites, an infection of cultured salmonids in the Pacific northwest, does produce extrasporogonic stages that are transmissible by injection of blood from infected fish into the peritoneum of naïve fish.…”

Section: Kudoa Clupeidae Development In Atlantic Menhadenmentioning

confidence: 99%

Myxosporean plasmodial infection associated with ulcerative lesions in young-of-the-year Atlantic menhaden in a tributary of the Chesapeake Bay, and possible links to Kudoa clupeidae

Reimschuessel¹,

Gieseker²,

Driscoll³

et al. 2003

Dis. Aquat. Org.

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Ulcers in Atlantic menhaden Brevoortia tyrannus (Latrobe) (Clupeidae), observed along the USA east coast, have been attributed to diverse etiologies including bacterial, fungal and, recently, harmful algal blooms. To understand the early pathogenesis of these lesions, we examined juvenile Atlantic menhaden collected during their seasonal presence in Chesapeake Bay tributaries from April to October 1999 and from March to August 2000. We conducted histopathological examinations of young-of-the-year fish from the Pocomoke River tributary, which has a history of fish mortalities and high lesion prevalence. Kudoa clupeidae (Myxozoa: Myxosporea) spores were present in the muscles of fish collected in both years. Of the fish assessed by histology in April, 5 to 14% were infected, while in May 90 to 96% were infected. Infection rates remained high during the summer. Mature spores were primarily located within myomeres and caused little or no observable pathological changes. Ultrastructure showed spores with capsulogenic cells bearing filamentous projections, and a basal crescentic nucleus with mottled nucleoplasm containing cleaved, condensed chromatin. Also, a highly invasive plasmodial stage of a myxozoan was found in the lesions of juvenile Atlantic menhaden. The plasmodia were observed in fish collected between May and July, with the maximum occurrence in late June 1999 and late May 2000. Plasmodia penetrated and surrounded muscle bundles, causing grossly observable raised lesions in 73% of all fish infected with this invasive stage. Plasmodia were also detected in the visceral organs, branchial arches, and interocular muscles of some fish. Some of the invasive extrasporogonic plasmodial lesions were associated with ulcers and chronic inflammatory infiltrates. The plasmodial stage appeared to slough out of the tissue with subsequent evidence of wound healing. Ultrastructure showed plasmodia with an elaborate irregular surface, divided into distinct ectoplasm and endoplasm; the latter contained numerous spherical vegetative nuclei, secondary generative cells, and occasional cell doublets. Our ultrastructural studies indicate that the plasmodial organisms, which are important in the etiology of the skin lesions, are myxozoans, and they may represent early stages of K. clupeidae. KEY WORDS: Atlantic menhaden · Brevoortia tyrannus · Kudoa clupeidae · Myxosporea · Plasmodia · LesionsResale or republication not permitted without written consent of the publisher

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Section: Kudoa Clupeidae Development In Atlantic Menhadenmentioning

confidence: 99%

Myxosporean plasmodial infection associated with ulcerative lesions in young-of-the-year Atlantic menhaden in a tributary of the Chesapeake Bay, and possible links to Kudoa clupeidae

Reimschuessel¹,

Gieseker²,

Driscoll³

et al. 2003

Dis. Aquat. Org.

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“…It has been responsible for huge declines of the wild rainbow trout population in more than 22 US states (Hedrick et al 1998). The passively floating actinospores play a key role in the spread of the infective sporozoites, but myxozoan actinospores do not remain infective for as long as myxospores, which are able to retain their infectivity for more than 20 years (El-Matbouli, Fischer-Scherl and Hoffmann, 1992). Waterborne M. cerebralis triactinomyxontype actinospores have to invade their host in less than 60 h after release (Markiw, 1992), and thus would benefit from functional adaptations for adequate host recognition.…”

Section: Introductionmentioning

confidence: 99%

Polar filament discharge of Myxobolus cerebralis actinospores is triggered by combined non-specific mechanical and chemical cues

Kallert

El‐Matbouli²,

Haas

2005

Parasitology

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S U M M A R YThis study presents initial evidence for the requirement of both chemical and mechanical stimuli to discharge polar capsules of Myxobolus cerebralis actinospores, the causative agent of salmonid whirling disease. The obligate need for combined discharge triggers was concluded from data obtained in a before/after experimental set-up carried out with individual locally immobilized actinospores. Homogenized rainbow trout mucus as chemostimulus and tangency of the apical region of the spores to achieve mechanical stimulation were applied subsequently. The actinospores showed discharged polar filaments exclusively when mucus substrate application was followed by touching the polar capsule-bearing region, but not when either stimulus was offered solely to the same individuals. We measured filament discharge rates to mucus preparations in a microscopic assay using supplementary vibration stimuli to ensure mechanical excitation. The actinospores responded similarly to different frequencies, which suggested a touch-sensitive recognition mechanism. Discharge specificity for salmonid mucus could not be confirmed, as mucus of common carp and bream could trigger similar filament expulsion rates. To a lesser extent homogenized frog epidermis and bovine submaxillary mucin could also stimulate the attachment reaction. In contrast, mucus of a pulmonate freshwater snail elicited no response.

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“…Myxozoans are well-known parasites of fish but many of their characteristics, including multi-'Addressee for correspondence. E-mail: rphedrick@ucdavis.edu cellular developmental and sporogonic stages, and modes of transmission have only recently been described (El-Matbouli et al 1992, 1995, El-Matbouli & Hoffmann 1998. Beginning in 1983, Wolf & Markiw published a series of papers describing experiments demonstrating that the Life cycle of M, cerebralis involved 2 hosts, a salmonid fish and an aquatic oligochaete worm (Wolf & Markiw 1981, 1984, Markiw & Wolf 1983a, b, Wolf et al 1986).…”

Section: Introductionmentioning

confidence: 99%

A nested polymerase chain reaction for the detection of genomic DNA of Myxobolus cerebralis in rainbow trout Oncorhynchus mykiss

Andrée¹,

MacConnell²,

Hedrick³

1998

Dis. Aquat. Org.

126

122

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A nested polymerase chain reaction (PCR) test was developed to amplify a segment of the 18s rRNA gene from Myxobolus cerebralis, the agent causing whirling disease in salmonid fish. The PCR amplifies a 415 bp amplicon that was identified by dideoxynucleotide terminated sequencing to be identical to the known 18s rDNA sequence of M. cerebralis. There was no amplification of genomic DNA from 4 other myxosporean parasites of salmonid fish from the genus Myxobolus incl.uding M. arcticus, M. insidiosus, M, neurobius, and )\/I. squamalis. The efficacy of the PCR test to detect early infections was demonstrated by amplificat~on of the 415 bp fragment from experimentally exposed rainbow trout Oncorhynchus mykiss at 2 h and at 1, 2, and 3 wk postexposure to actinosporean stages (triactinomyxons) of M. cerebralis. In contrast, standard microscopic examinations of stained tissue sections of the same fish used for PCR were less reliable in detecting the presence of the parasite Additional examinations of fish 5 mo postexposure, after sporogenesis had occurred, found the PCR to be a more reliable indicator of infection than the pepsin-trypsin digest (PTD) method, paricularly when trout were experimentally exposed to low levels of the infectious stages of the parasite. The PCR was able to amplify to detectable levels the equivalent of a single sporoplasm of M. cerebralis as found in a tissue sample. This test improves the detection of M. cerebralis because it can detect the presence of the parasite: (1) in both hosts, (2) in all known stages of its life cycle, and (3) at lower thresholds than currently used diagnostic methods. Lastly, the PCR test I S less susceptible to morphological mlsidentifications of the spores that can occur with current microscopic procedures.

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Present knowledge on the life cycle, taxonomy, pathology, and therapy of some Myxosporea spp. important for freshwater fish

Cited by 113 publications

References 44 publications

Myxosporean plasmodial infection associated with ulcerative lesions in young-of-the-year Atlantic menhaden in a tributary of the Chesapeake Bay, and possible links to Kudoa clupeidae

Myxosporean plasmodial infection associated with ulcerative lesions in young-of-the-year Atlantic menhaden in a tributary of the Chesapeake Bay, and possible links to Kudoa clupeidae

Polar filament discharge of Myxobolus cerebralis actinospores is triggered by combined non-specific mechanical and chemical cues

A nested polymerase chain reaction for the detection of genomic DNA of Myxobolus cerebralis in rainbow trout Oncorhynchus mykiss

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