Three Myxosporeans Found in the Cranial and Branchial Tissues of Rainbow Trout in California

Hedrick, Ronald P.; Wishkovsky, A.; Modin, J. C.; Toth, R. J.

doi:10.1577/1548-8667(1991)003<0055:tmfitc>2.3.co;2

Cited by 15 publications

(11 citation statements)

References 10 publications

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“…Thus, in rainbow trout exposed to M. cerebralis, specific antibodies were not present until 12 weeks after exposure (Ryce, 2003), whereas anti-PKX antibodies were detected as early as six weeks p.e. (Hedrick et al, 1991). When turbot were challenged with E. scophthalmi, specific antibodies were detected as soon as 48 days p.e.…”

Section: Specific Immune Responsementioning

confidence: 94%

Fish immune response to Myxozoan parasites

Sitjà‐Bobadilla

2008

Parasite

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Summary :Myxozoan parasites are responsible for important economic losses among fisheries and aquaculture industries, and hence the high interest in studying the immune response of fish against them. The most important data available concerning the immune response of fish against myxosporeans are reviewed, with emphasis on the different innate and adaptive immune mechanisms, their relationship with natural and acquired resistance and the strategies to control and prevent myxosporoses. Cellular effectors (lymphocytes, granulocytes, phagocytes, non-specific cytotoxic cells, rodlet cells) and humoral factors (lysozyme, peroxidades, antiproteases, complement, specific antibodies) have been examined for several myxosporoses, and some immune relevant genes have been studied. This information will be crucial for the future development of vaccines and other preventive strategies such as immunomodulation and selection of disease-resistant strains

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Section: Specific Immune Responsementioning

confidence: 94%

Fish immune response to Myxozoan parasites

Sitjà‐Bobadilla

2008

Parasite

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“…complicate this approach. Also, multiple concurrent myxosporean infections occurring in Lhe sanie fish (Hedrick et al 1991) could confuse attempts to use fish serum antibodies for diagnostic purposes. The proper diagnosis of whirling disease is paramount in certain areas and consequences of a positive diagnosis of M. cerebralis may be severe (i.e.…”

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.

125

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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“…The spores were differentiated by means of histology, and those found in brain tissue were deemed an unidentified Myxobolus sp. In California, three myxosporeans were found in the cranial tissues of a single population of rainbow trout (Hedrick et al 1991); these spores measured 12.7 ϫ 10.5 m. In Utah, PTD revealed Myxobolus spores from Bear Lake cutthroat trout. Although PCR was negative for M. cerebralis, our discriminatory PCR confirmed the presence of the neurotropic Myxobolus sp.…”

Section: Discussionmentioning

confidence: 99%

Discriminating between a Neurotropic Myxobolus sp. and M. cerebralis, the Causative Agent of Salmonid Whirling Disease

2004

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While screening salmonids for Myxobolus cerebralis, the causative agent of whirling disease, we detected a neurotropic Myxobolus sp. that is morphologically similar to the M. cerebralis spore in brain and other nervous tissue. We developed a polymerase chain reaction (PCR)-based diagnostic technique to differentiate the two species of Myxobolus. Primers were designed for a 277-base-pair (bp) sequence within the 18S ribosomal DNA (rDNA) gene, and the restriction enzyme Mse-I was chosen to cut the amplified product into diagnostic fragments. When electrophoresed in an acrylamide gel, M. cerebralis yielded a two-band pattern while the neurotropic Myxobolus sp. yielded a three-band pattern. This diagnostic method has resolved cases in which the pepsin-trypsin digest screening test indicated Myxobolus spores but histological examination or PCR was negative for M. cerebralis. We were also able to eliminate M. kisutchi as the neurotropic Myxobolus sp. using spores from infected coho salmon Oncorhynchus kisutch obtained from Minter Creek, Washington (the type host and type location for M. kisutchi), by designing primers to amplify a larger 683-bp amplicon within the 18S rDNA gene. Sequencing of this 683-bp product from the neurotropic Myxobolus sp. and M. kisutchi was then performed. Sequence alignment and phylogenetic analysis on the neurotropic Myxobolus sp. and M. kisutchi as well as M. cerebralis, M. arcticus, M. neurobius, M. insidiosus, and M. squamalis suggest that the neurotropic Myxobolus sp. is a new species.

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Three Myxosporeans Found in the Cranial and Branchial Tissues of Rainbow Trout in California

Cited by 15 publications

References 10 publications

Fish immune response to Myxozoan parasites

Fish immune response to Myxozoan parasites

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

Discriminating between a Neurotropic Myxobolus sp. and M. cerebralis, the Causative Agent of Salmonid Whirling Disease

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