{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T10:00:55Z","timestamp":1778234455127,"version":"3.51.4"},"reference-count":22,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2021,8,28]],"date-time":"2021-08-28T00:00:00Z","timestamp":1630108800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2021,8,28]],"date-time":"2021-08-28T00:00:00Z","timestamp":1630108800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Parasites Vectors"],"abstract":"<jats:title>Abstract<\/jats:title><jats:sec>\n                <jats:title>Background<\/jats:title>\n                <jats:p>In Norway, x-cell parasites associated with disease in farmed salmonids have been known as a rare phenomenon for two decades. These parasites cause systemic infections in farmed rainbow trout (<jats:italic>Oncorhynchus mykiss<\/jats:italic>) and Atlantic salmon (<jats:italic>Salmo salar<\/jats:italic>), but have  so far not been characterized and described.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Methods<\/jats:title>\n                <jats:p>The x-cells from several cases of diseased fish were studied using light and electron microscopy, and by phylogenetic analysis based on small subunit ribosomal RNA (<jats:italic>SSU<\/jats:italic> rRNA) gene sequences.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Results<\/jats:title>\n                <jats:p>We describe here the x-cell parasite as a new species in a new genus, <jats:italic>Salmoxcellia vastator<\/jats:italic> n. gen., n. sp. Phylogenetic analyses placed <jats:italic>Salmoxcellia<\/jats:italic> n. gen. together with <jats:italic>Gadixcellia<\/jats:italic> among the xcelliids, a group of perkinsozoan alveolates. The new genus and species were found to have vacuolate plasmodial x-cells filled with lipid droplets, and an electron-dense alveolar pellicle. Electron-dense cytoplasmic inclusions, which are characteristic of the other xcelliid genera <jats:italic>Xcellia<\/jats:italic> and <jats:italic>Gadixcellia<\/jats:italic>, are lacking in <jats:italic>Salmoxcellia<\/jats:italic> n. gen. These x-cell plasmodia divide by plasmotomy and occur as aggregates in the host tissues, particularly in blood-rich tissues such as those of the kidney, red musculature, heart and liver. Host reaction and the refractive lipid droplets in the x-cells result in <jats:italic>S. vastator<\/jats:italic> n. gen., n. sp. aggregates appearing as white patches in the tissues.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Conclusions<\/jats:title>\n                <jats:p>We describe a new genus and species of xcelliid protist parasites from two very important farmed fish species and provide molecular methods for detection. The new parasite is associated with disease, but more importantly it has a spoiling effect on farmed salmonid fillets, rendering them unsuitable for sale. Consequently, this parasite represents a threat to the aquaculture industry.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Graphical abstract<\/jats:title>\n                \n              <\/jats:sec>","DOI":"10.1186\/s13071-021-04886-0","type":"journal-article","created":{"date-parts":[[2021,8,28]],"date-time":"2021-08-28T09:02:52Z","timestamp":1630141372000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["A novel protist parasite, Salmoxcellia vastator n. gen., n. sp. (Xcelliidae, Perkinsozoa), infecting farmed salmonids in Norway"],"prefix":"10.1186","volume":"14","author":[{"given":"Egil","family":"Karlsbakk","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Cecilie Flatnes","family":"Nyst\u00f8yl","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Heidrun","family":"Plarre","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Are","family":"Nylund","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"297","published-online":{"date-parts":[[2021,8,28]]},"reference":[{"key":"4886_CR1","unstructured":"Karlsbakk E, Myklebust CF, Watanabe K, Nylund A. A systemic disease of cultured rainbow trout, associated with an unidentified protist showing affinities to the Perkinsea. In: Abstracts. 11th International Conference of the EAFP 2003 Diseases of Fish and Shellfish, St. Julians, 21\u201326 Sept 2003. p. 28."},{"key":"4886_CR2","first-page":"46","volume":"31","author":"A Nylund","year":"2006","unstructured":"Nylund A, Karlsbakk E, Myklebust C, Watanabe K. Ny parasitt p\u00e5vist hos regnbue\u00f8rret og laks i oppdrett p\u00e5 Vestlandet [New parasite detected in rainbow trout and salmon in western Norway]. Nor Fiskeoppdr. 2006;31:46\u20139 (in Norwegian).","journal-title":"Nor Fiskeoppdr"},{"key":"4886_CR3","doi-asserted-by":"publisher","first-page":"967","DOI":"10.1017\/S0031182009006507","volume":"136","author":"MA Freeman","year":"2009","unstructured":"Freeman MA. X-cell parasites in the European dab Limanda limanda are related to other X-cell organisms: a discussion on the potential identity of this new group of parasites. Parasitology. 2009;136:967\u201380.","journal-title":"Parasitology"},{"key":"4886_CR4","doi-asserted-by":"publisher","first-page":"15","DOI":"10.1186\/1756-3305-4-15","volume":"4","author":"MA Freeman","year":"2011","unstructured":"Freeman MA, Eydal M, Yoshimizu M, Watanabe K, Shinn AP, Miura K, et al. Molecular identification and transmission studies of X-cell parasites from Atlantic cod Gadus morhua (Gadiformes: Gadidae) and the northern black flounder Pseudopleuronectes obscurus (Pleuronectiformes: Pleuronectidae). Parasites Vectors. 2011;4:15.","journal-title":"Parasites Vectors"},{"key":"4886_CR5","doi-asserted-by":"publisher","first-page":"1645","DOI":"10.1016\/j.cub.2017.04.045","volume":"27","author":"M Freeman","year":"2017","unstructured":"Freeman M, Fuss J, Kristmundsson A, Bjorb\u00e6kmo MFM, Mangot J-F, del Campo J, et al. X-cells are globally distributed, genetically divergent fish parasites related to perkinsids and dinoflagellates. 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