Further evidence for a viral etiology in plasmacytoid leukemia of Chinook salmon Oncorhynchus tshawytscha

Kent, Michael L.; Dawe, S. C.

doi:10.3354/dao015115

Cited by 23 publications

(9 citation statements)

References 10 publications

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“…Bernstein (1984) also found a Type C virus in pike lymphoid tumours. Plasmacytoid leukemia caused by a retroviral agent (Kent et al 1990, Eaton & Kent 1992, Eaton et al 1993, Kent & Dawe 1993) has caused mass mortalities in cultured chinook salmon Oncorhynchus tsha wy tscha (Walbaum, 1792) (Kent et al 1990).…”

Section: Introductionmentioning

confidence: 99%

Sarcoma in the thymus of juvenile meagre Argyrosomus regius reared in an intensive system

Soares¹,

Leitão²,

Moreira³

et al. 2012

Dis. Aquat. Org.

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Juvenile meagre Argyrosomus regius (Asso, 1809) maintained in experimental conditions developed lateral and/or bilateral circular-shaped sarcoma within the opercular cavity. The sarcoma was dense, reddish and its growth from the branchial arch exerted pressure on the operculum forcing it to open. Histologically, the neoplasm exhibited marked proliferation of mesenchymal connective tissue composed largely of fusiform cells, which developed in a solid pattern accompanied by abundant mononuclear cell types. Multifocal areas of discrete necrosis were also observed, compatible with a sarcomatous proliferation. The immunological parameters analysed suggested an inflammatory response. No bacteria were isolated from the hematopoietic organs. However, Vibrio species, components of the normal seawater flora, were isolated from the tumour, which may have had a role in eliciting the immune response. No evidence of viral pathogens was found by electron microscopy. In order to look for cytogenetic alterations often linked to sarcomas, the diploid number and karyotype of this species were determined for the first time. An increase in the aneuploidy level was observed in sarcoma cell metaphase stages compared to other tissues. The aetiology of this tumour remains unknown.

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Section: Introductionmentioning

confidence: 99%

Sarcoma in the thymus of juvenile meagre Argyrosomus regius reared in an intensive system

Soares¹,

Leitão²,

Moreira³

et al. 2012

Dis. Aquat. Org.

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“…We presume however, that the progressive spread of lymphoblasts from sites of proliferation (principally the h d n e y and spleen) via the vasculature and their replication in distant tissues results in a leukemic-like condition which alone can b e fatal as demonstrated for the plasmacytoid leukemia of adult chinook salmon (Kent & Dawe 1990). The significant drop in hematocrits and impairment of the critical function of other organs (kidney, liver, posterior intestine) may cause death directly.…”

Section: Discussionmentioning

confidence: 99%

“…The microsporidian infections shared certain similarities to a plasmacytoid leukemia in adult chinook salmon reared in seawater as described by . However, experimental transmission studies of the plasmacytoid leukemia have not demonstrated a role of the microsporidium in the observed disease (Kent & Dawe 1990). …”

Section: Introductionmentioning

confidence: 99%

Experimental infections with Enterocytozoon salmonis Chilmonczyk, Cox, Hedrick (Microsporea): an intranuclear microsporidium from Chinook salmon Oncorhynchus tshawytscha

Hedrick¹,

Groff²,

Baxa³

1991

Dis. Aquat. Org.

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ABSTRACT. Infections were induced in juvenile chinook salmon O n c o r h~: 1 i1.S tshawytscha by intraperitoneal injections of cells from the kidney of fish with naturally-uccurring infections of E~~terocytozoon salmonis. A mild hyperplasia of the hematopoietic tissues of the kidney and spleen were observed 3 wk after injection at water temperatures of 15 'C. By 5 wk postinjection, populat~ons of lymphoblasts, some of which contained intranuclear forms ot the parasite, were abundant in the kidney and spleen but also occurred in the leptomeninges, skeletal muscle, coelomic mesenteries, hepatic sinusoids and periorbital connective tissues of the eye. Plasmodial stages were abundant within the nucleus of blast cells in stained kidney imprints from infected fish but spores were only rarely detected. At 7 wk postinjection, the infections had progressed to a severe systemic diseasc: with features similar to naturally-occurring infections with the microsporidium. These included anemia accompanied by a leukemic condition in which lymphoblastic cells were found disseminated throughout most tissues including prominent accumulations in the lamina propria of the posterior intestine. Mortalities occurred among infected fish between 53 and 60 d postinjection and infections were detected in most survivors at the end of the study at 9 wk postinjection. Moderate numbers of spores were found most often in dead fish and survivors examined at the end of the study (63 d). The potential for treatment of infections with fumagillin DCH was demonstrated by the absence of mortalities and microscopic signs of clinical infections and a marked decrease i.n detection of the parasite among chinook salmon fed the drug (0.1 g kg-' food at 1 5 % body weight d-') between 3 and 7 wk postinjection.

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“…21 Experimental transmission trials using cell-free, ultra-filtrated inoculum from kidneys and spleens of fish with clinical plasmacytoid leukemia that had received antiprotozoal treatment resulted in successful transmission of the disease. 33 Together, these studies suggest that plasmacytoid leukemia in Chinook salmon is caused by a retrovirus, but the role of protozoal and bacterial agents as possible cofactors in the etiopathogenesis of this disease remains undetermined at this time. 34 67 The diseases manifest as cutaneous round cell tumors with a low prevalence in the summer but increased prevalence in the fall, winter, and spring.…”

Section: Chinook Salmon Plasmacytoid Leukemiamentioning

confidence: 99%

“…33,35 Plasmacytoid leukemia has been associated with a retrovirus, but coinfection with Enterocytozoon salmonis, a microsporidian parasite, and Renibacterium salmoninarum, the causative agent of bacterial kidney disease, is disproportionately common among infected fish. 33 Evaluation of renal and periocular tissues from Chinook salmon with natural and experimentally induced diseases revealed 110 nm diameter Figure 10. Skin of trunk, yellow perch discrete epidermal hyperplasia.…”

Section: Chinook Salmon Plasmacytoid Leukemiamentioning

confidence: 99%

Pathology of Tumors in Fish Associated With Retroviruses

2013

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Thirteen proliferative diseases in fish have been associated in the literature with 1 or more retroviruses. Typically, these occur as seasonal epizootics affecting farmed and wild fish, and most lesions resolve spontaneously. Spontaneous resolution and lifelong resistance to reinfection are 2 features of some piscine retrovirus-induced tumors that have stimulated research interest in this field. The purpose of this review is to present the reader with the epidemiological and morphological features of proliferative diseases in fish that have been associated with retroviruses by 1 or more of the following methods: detection of C-type retroviruslike particles or reverse transcriptase activity in tumor tissues; successful tumor transmission trials using well-characterized, tumor-derived, cell-free inocula; or molecular characterization of the virus from spontaneous and experimentally induced tumors. Two of the diseases included in this review, European smelt spawning papillomatosis and bicolor damselfish neurofibromatosis, at one time were attributed to a retroviral etiology, but both are now believed to involve additional viral agents based on more recent investigations. We include the latter 2 entities to update the reader about these developments. Keywords fishes, piscine, neoplasms, Retroviridae, tumor virus infections, oncogenic virusesMembers of several virus families have been implicated in the etiology of tumors in fish. The literature contains numerous publications in which members of virus families Herpesviridae, Papillomaviridae, and Retroviridae are associated with the development of tumors in fish. In this report, we review the epidemiological, gross, microscopic, and ultrastructural features of 13 piscine tumors reported in the literature for which there is evidence of a retroviral involvement. In some instances, the evidence supporting a retroviral association is compelling and includes viral sequencing and successful transmission trials using a well-characterized inoculum. In other instances, a retroviral association is based on detection of retrovirus-like particles or reverse transcriptase activity in tissues from proliferative lesions. These viruses have been the subject of several reviews. 4,48,49 For this review, we have accessed archival materials primarily from the archived Registry of Tumors in Lower Animals as well as cases from the Aquatic Animal Health Program at the College of Veterinary Medicine, Cornell University.Before evaluating a lesion, any case of a fish tumor must be considered in light of the fish as an ectotherm. Much of the biology of fish is affected by water temperature and seasonality of various physiological processes. It is well known that the immune response in fish is modified by changes in water temperature and other physiological stressors, such as spawning activity. 39 A review of the case records of most fish disease diagnostic laboratories will show the largest number of neoplastic cases to occur in the spring, a time of changing water temperature and a tim...

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Further evidence for a viral etiology in plasmacytoid leukemia of Chinook salmon Oncorhynchus tshawytscha

Cited by 23 publications

References 10 publications

Sarcoma in the thymus of juvenile meagre Argyrosomus regius reared in an intensive system

Sarcoma in the thymus of juvenile meagre Argyrosomus regius reared in an intensive system

Experimental infections with Enterocytozoon salmonis Chilmonczyk, Cox, Hedrick (Microsporea): an intranuclear microsporidium from Chinook salmon Oncorhynchus tshawytscha

Pathology of Tumors in Fish Associated With Retroviruses

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