DOCSLIB.ORG

<I>Loma Salmonae

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
<I>Loma Salmonae Evaluation of Rainbow Trout as a Model for use in Studies on Pathogenesis of the Branchial Microsporidian Loma salmonae DAVID J. SPEARE, DVM, DVSC, GARTH J. ARSENAULT, ENV TECH, AND MELANIE A. BUOTE, BS Abstract _ Loma salmonae is an economically important gill microsporidian pathogen of pen-reared chinook and coho salmon. Chinook and coho salmon are generally poorly suited for use in laboratory studies because of their high mortality rates when infected with L. salmonae and their high-level of susceptibility to other infectious diseases. Using gill tissue from chinook salmon that contained mature xenomas laden with L. salmonae spores, we successfully transmitted the infection to rainbow trout. The infection developed in an identical manner and over a similar time course in trout as for chinook salmon. In contrast, we were unable to transmit the infection to other candidate salmonid species, including Atlantic salmon, brook trout, or arctic charr. Gill tissue from experimentally infected rainbow trout was then used to successfully transmit the parasite to other trout. Horizontal transmission was documented from infected to naive tankmates. Analysis of these results indicated that L. salmonae can have a complete life cycle in trout and produce viable spores. Although abundant xenomas developed in the gills of infected trout, the fish did not have clinical signs and there were no fatalities. We concluded that use of rainbow trout offers several key advantages for study of the pathobiologic characteristics of L. salmonae. Gill disease associated with the microsporidian parasite Loma mission of the organism, gill material from infected chinook salmonae is an emerging problem affecting the marine aquacul- salmon was obtained from another research worker (Dr. M. L. ture production of Pacific salmon, most notably chinook salmon Kent, Department of Fisheries and Oceans, Pacific Biological (Oncorhynchus tshawytscha) and, to a lesser extent, coho salmon Station, Nanaimo, British Columbia, Canada ). Gill arches from (O. kisutch) (1–6). Parasites develop in the vasculature of the naturally or experimentally infected fish were removed, placed gills to form large spore-laden xenomas (2–6). Loma salmonae in Earl’s balanced salt solution, and transported on ice. Material also infect rainbow trout (O. mykiss) (7–9); however, in contrast was kept chilled and used 3 days after harvest. to the Pacific salmon, the clinical effects on these fish vary con- In subsequent studies, spores were obtained from gills of in- siderably (9). Furthermore, on the basis of unpublished fected rainbow trout. Spores were obtained 7 to 8 weeks after observations from diagnostic materials sent to the Fish Health fish were exposed to spores during the previous (initial) study. Unit of the Atlantic Veterinary College, L. salmonae is often de- Fish were housed in water at a temperature of 14.58C. Fish with tected in groups of trout that do not have a history of clinical abundant xenomas were selected, euthanatized with an overdose disease, whereas this is not the clinical history for chinook salmon. of benzocaine dissolved in water (100 mg of benzocaine/L of Because of the restrictive nature of current regulations per- water), gill arches were removed, and tissues were used 1 to 3 h taining to the use of therapeutic agents in aquaculture, licenced after collection. therapeutic agents are not available for treating fish infected Fish: All procedures involving live fish were performed accord- with L. salmonae. Accordingly, there is a need to study the ing to guidelines of the Canadian Council on Animal Care. pathobiologic characteristics of L. salmonae in an effort to un- Specific protocols were reviewed by the institutional animal care cover management factors that could limit the economic effects committee (University of Prince Edward Island, Charlottetown, of infection. Laboratory studies of this disease would benefit by Prince Edward Island, Canada). the availability of a species other than chinook salmon, even Juvenile rainbow trout (mean weight, 4 g) were obtained from though they are the principal aquaculture species affected by L. a certified disease-free (specific pathogens) commercial hatch- salmonae. Chinook salmon have proven to be difficult to work ery on Prince Edward Island which did not have a history of L. with in laboratory studies (10) and often become diseased or salmonae infection. Fifteen fish were arbitrarily selected from die because of a range of other endemic infectious diseases, par- 1,000 received and were examined histologically to rule out L. ticularly when the fish are stressed. Rainbow trout, in contrast, salmonae or other diseases not included in federal certification are a relatively hardy fish that are frequently used in laboratory procedures. During the studies, fish weighed from 4 to > 147 g. studies (11). They have been the salmonid species used as a Variations in weight were due to growth, because the various model for many studies, and their requirements and physiologic studies were conducted sequentially. One hundred 3-g Atlantic responses are well documented (11). salmon (Salmo salar) and 3-g brook trout (Salvelinus fontinalis) Our purpose was to evaluate the suitability of rainbow trout as were also acquired from the hatchery where we purchased the an animal model for L. salmonae infections with particular em- trout. One hundred 6-g Arctic charr (Salvelinus alpinus) were phasis on the ability of this parasite to complete its life cycle in a obtained from another commercial hatchery, also with certified manner similar to that seen in naturally and experimentally in- disease-free status. Samples of these other species were exam- fected chinook salmon. ined 4 weeks after their arrival to detect any evidence of L. Materials and Methods salmonae or L. fontinalis. Methods of infection: Fish were exposed to infected gill mate- Source of Loma salmonae spores: In the initial studies on trans- rial by two ways. A feeding method was devised on the basis of Department of Pathology & Microbiology, Atlantic Veterinary College, University previously published methods (6). Approximately 2 g of gill tis- of Prince Edward Island, Charlottetown, Prince Edward Island, Canada C1A 4P3 sue was minced into pieces approximately 0.2 cm2. This tissue 55 was then fed to 20 to 30 fish in a tank. An intubation method was native salmonid species (two non-Oncorhynchus genera). Using devised on the basis of information gained during personal com- spores derived from infected trout, we intubated 20 Atlantic munications (12). Filament cartilage was dissected from salmon, 20 brook trout, and 20 arctic charr. Twenty naive rain- harvested gills, which were then manually crushed. Fish were bow trout were also intubated and used as control fish. Infection manually restrained or lightly anesthetized in a solution of ben- status of fish was monitored weekly through 9 weeks. At week 7, zocaine (40 mg of benzocaine/L of water), and 0.1 to 0.2 ml of samples were collected for histologic assessment to determine the gill tissue-diluent was administered, using gastric intubation. whether xenomas or other evidence of disease were evident in Water supply, housing and characteristics: On arrival, fish were nonbranchial tissues in these test species. During this study, fish stocked in 70-L (salmon, brook trout, arctic charr) or 500-L fi- were housed for 14 weeks in a single 70-L tank supplied with berglass tanks (trout) that received water pumped from a well at freshwater at a temperature of 14.58C. 108C. Fish were fed a recommended amount (13) of a commer- Study 4. To assess whether the final number of xenomas that cially available diet until they entered a study. All studies were developed on the gills of infected fish was correlated with the conducted in 70-L circular tanks supplied with freshwater (2.7 infective dose received, we infected 75 rainbow trout via intuba- L/ min). Dissolved oxygen concentrations were maintained be- tion with 3 dilutions (1:1, 1:10, 1:100) of a preparation of spores. tween 8 and 11 mg/L. For studies conducted with the water A fourth group of 75 fish was intubated with water only. The 1:1 temperature of 14.58C, water from the well was heated and mixed dilution yielded a dose of approximately 4.8 X 106 spores/fish, in a header tank with ambient-temperature water until 14.58C determined on the basis of calculations derived from enumerat- was reached. To avoid supersaturation problems, heated water ing the number of xenomas used and a volumetric calculation was degassed through a trickle column before use. of the reported theoretical maximum number of spores per Evaluating infection status: For studies conducted by using xenoma (8). Seven weeks after intubation, fish were euthana- water at a temperature of 14.58C, the infection status of fish was tized by immersion in an overdose of benzocaine. The second assessed two or more times, usually during the period 5 to 7 gill arch on the left side of each fish was removed, and number weeks after initial exposure to infective material. For studies con- of xenomas was counted, using a compound stereomicroscope. ducted by using water at colder temperatures or when species Number of gill filaments on the arch was also counted. Data other than rainbow trout were used, more-frequent screening were reported as number of xenomas per filament to compen- during a longer period was used. During each assessment, fish sate for any differences in gill surface area that may have resulted were anesthetized in benzocaine (60 mg of benzocaine/L of from potential differential growth rates between groups of fish water). The operculum was lifted, and the gills were examined, exposed to differing doses. using a dissecting microscope. The entire surface of the second Effect of dilution on number of xenomas formed was assessed gill arch of each fish was examined for evidence of xenomas.
Load more

Recommended publications
  • Full Text in Pdf Format
    DISEASES OF AQUATIC ORGANISMS Vol. 34: 211-216,1998 Published November 30 Dis Aquat Org Occurrence of Loma cf. salmonae in brook, brown and rainbow trout from Buford Trout Hatchery, Georgia, USA Joel A. ad er', Emmett B. Shotts ~r~**,Walton L. Steffens3,Jiri ~om~ 'USDA, Agriculture Research Service, Fish Diseases and Parasites Research Laboratory, Auburn, Alabama 36830, USA 'National Fish Health Research Laboratory, Kearneysville. West Virginia 25430, USA 3Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens. Georgia 30601, USA 41nstitute of Parasitology, Czech Academy of Sciences. Ceske Bud6jovice. Czech Republic ABSTRACT During a 6 mo study of moribund trout from Buford hatchery, Buford, Georgia, USA, a Lon~acf. salmonae rnicrosporidian parasite was studied in the gills of brook trout Salvelinus fontinahs, brown trout Salmo trutta, and rainbow trout Oncorhynchus mykiss. This parasite was morphologically similar to L. salmonae and L, fontinalis but differed in spore size. Scanning and transmission electron microscopy demonstrated that xenomas were embedded in gill filaments. Transmission electron micro- graphs prepared from fresh tissue showed mature spores with 12 to 15 turns of their polar tube. Spore diameters for the Georgia strain from formalin-fixed gill tissues measured 3.5 (SD iO.l) by 1.8 (SD 20.1) pm. Electron micrographs of formalin-fixed, deparaffinized tissues of rainbow trout from Pennsylvania and West Virginia show spores with a diameter of 3.5 (k0.2)by 1.7 (k0.1) pm and 3.4 (i0.2)by 1.8 (iO.l) pm, respectively. Transmission electron micrographs of spores from Pennsylvania and West Virginia show that mature spores from both states hdd 13 to 15 turns of their polar tubes.
    [Show full text]
  • D070p001.Pdf
    DISEASES OF AQUATIC ORGANISMS Vol. 70: 1–36, 2006 Published June 12 Dis Aquat Org OPENPEN ACCESSCCESS FEATURE ARTICLE: REVIEW Guide to the identification of fish protozoan and metazoan parasites in stained tissue sections D. W. Bruno1,*, B. Nowak2, D. G. Elliott3 1FRS Marine Laboratory, PO Box 101, 375 Victoria Road, Aberdeen AB11 9DB, UK 2School of Aquaculture, Tasmanian Aquaculture and Fisheries Institute, CRC Aquafin, University of Tasmania, Locked Bag 1370, Launceston, Tasmania 7250, Australia 3Western Fisheries Research Center, US Geological Survey/Biological Resources Discipline, 6505 N.E. 65th Street, Seattle, Washington 98115, USA ABSTRACT: The identification of protozoan and metazoan parasites is traditionally carried out using a series of classical keys based upon the morphology of the whole organism. However, in stained tis- sue sections prepared for light microscopy, taxonomic features will be missing, thus making parasite identification difficult. This work highlights the characteristic features of representative parasites in tissue sections to aid identification. The parasite examples discussed are derived from species af- fecting finfish, and predominantly include parasites associated with disease or those commonly observed as incidental findings in disease diagnostic cases. Emphasis is on protozoan and small metazoan parasites (such as Myxosporidia) because these are the organisms most likely to be missed or mis-diagnosed during gross examination. Figures are presented in colour to assist biologists and veterinarians who are required to assess host/parasite interactions by light microscopy. KEY WORDS: Identification · Light microscopy · Metazoa · Protozoa · Staining · Tissue sections Resale or republication not permitted without written consent of the publisher INTRODUCTION identifying the type of epithelial cells that compose the intestine.
    [Show full text]
  • Utrastructural and Molecular Description of a Microsporidia
    Ultrastructure and phylogeny of a microsporidian parasite infecting the big-scale sand smelt, Atherina boyeri Risso, 1810 in the Minho River, Portugal Marília Catarina dos Santos Margato Dissertation for Master in Marine Sciences and Marine Resources – Marine Biology and Ecology 2014 MARÍLIA CATARINA DOS SANTOS MARGATO Ultrastructure and phylogeny of a microsporidian parasite infecting the big-scale sand smelt, Atherina boyeri Risso, 1810 in the Minho River, Portugal Dissertation for Master’s degree in Marine Sciences and Marine Resources – Marine Biology and Ecology submitted to the Institute of Biomedical Sciences Abel Salazar, University of Porto, Porto, Portugal Supervisor – Doctor Carlos Azevedo Category – “Professor Catedrático Jubilado” Affiliation – Institute of Biomedical Sciences Abel Salazar, University of Porto Co-supervisor – Sónia Raquel Oliveira Rocha Category – Doctoral Student Affiliation – Institute of Biomedical Sciences Abel Salazar, University of Porto Agradecimentos A execução e entrega desta tese só foi possível com a ajuda e colaboração prestada por várias pessoas. A quem quero expressar os meus sinceros agradecimentos pelo apoio e motivação, nomeadamente: aos meus orientadores, Professor Doutor Carlos Azevedo e Sónia Rocha, pelos conselhos, dicas e enorme colaboração e orientação neste trabalho, sem os quais não seria possível a sua execução, à Doutora Graça Casal que, pelo trabalho desenvolvido neste filo, deu uma assistência imprescindível para o desenvolvimento desta tese, às técnicas Ângela Alves e Elsa Oliveira
    [Show full text]
  • Innate Susceptibility Differences in Chinook Salmon Oncorhynchus Tshawytscha to Loma Salmonae (Microsporidia)
    DISEASES OF AQUATIC ORGANISMS Vol. 43: 49–53, 2000 Published October 25 Dis Aquat Org Innate susceptibility differences in chinook salmon Oncorhynchus tshawytscha to Loma salmonae (Microsporidia) R. W. Shaw1,*, M. L. Kent2, M. L. Adamson3 1#9 26520 Twp Rd 512, Spruce Grove, Alberta T7Y 1G1, Canada 2Center for Salmon Disease Research, 220 Nash Hall, Oregon State University, Corvallis, Oregon 937331-3804, USA 3Department of Zoology, 6270 University Boulevard, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada ABSTRACT: Loma salmonae (Putz, Hoffman and Dunbar, 1965) Morrison & Sprague, 1981 (Micro- sporidia) is an important gill pathogen of Pacific salmon Oncorhynchus spp. in the Pacific Northwest. Three strains of chinook salmon O. tshawytscha were infected in 2 trials with L. salmonae by feeding of macerated infected gill tissue or per os as a gill tissue slurry. Intensity of infection was significantly higher in the Northern stream (NS) strain as compared to the Southern coastal (SC) and a hybrid (H) strain derived from these 2 strains. Both wet mount and histological enumeration of intensity of infec- tion demonstrated strain differences. Survival in the NS strain was significantly lower than the other strains. The NS strain may represent a naive strain and be less able to mount an effective immune response against the parasite. KEY WORDS: Loma salmonae · Microsporidia · Innate susceptibility Resale or republication not permitted without written consent of the publisher INTRODUCTION alimentary canal a L. salmonae spore is stimulated to extrude a polar filament which pierces a host cell, Loma salmonae (Putz, Hoffman and Dunbar, 1965) injecting the infective sporoplasm.
    [Show full text]
  • Impact of a Water Temperature Shift on Xenoma Clearance and Recovery Time During a Loma Salmonae (Microsporidia) Infection in Rainbow Trout Oncorhynchus Mykiss
    DISEASES OF AQUATIC ORGANISMS Vol. 58: 185–191, 2004 Published March 10 Dis Aquat Org Impact of a water temperature shift on xenoma clearance and recovery time during a Loma salmonae (Microsporidia) infection in rainbow trout Oncorhynchus mykiss Joy A. Becker*, David J. Speare Department of Pathology and Microbiology, Atlantic Veterinary College, Charlottetown, Prince Edward Island C1A 4P3, Canada ABSTRACT: Previous studies have modelled the relationship between water temperature and the rate of sporulation as defined by xenoma formation during microsporidial gill disease (MGD) in salmon caused by Loma salmonae. Although offering insight into the epidemiology of MGD, a key unexplored area is the role of temperature in the rate of xenoma dissolution including spore release into the environment, and this is crucial to our ability to model horizontal transmission of MGD within confined net-pen populations of farmed salmon. Results from a previous trial suggested that xenoma dissolution may be dramatically hastened as water temperature declines, thus introducing a critical anomaly into any predictive exercise. The data generated herein was evaluated using the statistics of survival analysis to re-establish the baseline relationship of xenoma formation and dissolution rela- tive to water temperature and to compare these results with those of previous studies. We infected 30 individuals of Oncorhynchus mykiss (Walbaum) with macerated xenoma-laden gill material, and afterwards allocated them to tanks with water temperatures of 11, 15, or 19°C and monitored them through a disease cycle. Xenoma onset and clearance times were similar to previous findings with both events being accelerated at higher water temperatures, thereby suggesting a similar tempera- ture response in the current strain to those used in previous studies.
    [Show full text]
  • Low Genetic Variation in the Salmon and Trout Parasite Loma Salmonae (Microsporidia) Supports Marine Transmission and Clarifies Species Boundaries
    Vol. 91: 35–46, 2010 DISEASES OF AQUATIC ORGANISMS Published July 26 doi: 10.3354/dao02246 Dis Aquat Org Low genetic variation in the salmon and trout parasite Loma salmonae (Microsporidia) supports marine transmission and clarifies species boundaries Amanda M. V. Brown1,*, Michael L. Kent2, Martin L. Adamson1 1Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada 2Department of Microbiology, Oregon State University, 220 Nash Hall, Corvallis, Oregon 97331, USA ABSTRACT: Loma salmonae is a microsporidian parasite prevalent in wild and farmed salmon spe- cies of the genus Oncorhynchus. This study compared ribosomal RNA (rDNA) and elongation factor-1 alpha (EF-1α) gene sequences to look for variation that may provide a basis for distinguishing pop- ulations. Specimens were collected from laboratory, captive (sea netpen farm and freshwater hatch- ery) and wild populations of fish. The host range included rainbow trout O. mykiss, Pacific salmon Oncorhynchus spp. and brook trout Salvelinus fontinalis from British Columbia, Prince Edward Island, Canada, from California, Colorado, Idaho, USA and from Chile. Both loci suggested that a variant in S. fontinalis (named ‘SV’) was a separate species. This was supported by the absence of similar variants in the source material (isolated from laboratory-held O. tshawytscha) and high diver- gence (1.4 to 2.3% in the rDNA and EF-1α) from L. salmonae in the type host and locality (O. mykiss in California). L. salmonae from freshwater and anadromous Oncorhynchus spp. were distinguished, providing a basis on which to evaluate possible sources of infection and suggesting geographic boundaries are important.
    [Show full text]
  • Information to Users
    INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or irxlistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Photographs included in the original manuscript have t)een reproduced xerographically in this copy. Higher quality 6” x 9” black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. Bell & Howell Information and Learning 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA 800-521-0600 UMI PATHOBIOLOGY OF LOMA SALMONAEz PROGRESSION OF INFECTION AND MODULATING EFFECTS OF INTRINSIC AND EXTRINSIC FACTORS. A Thesis Submitted to the Graduate Faculty in Partial Fulfilment of the Requirements for the Degree of Doctor of Philosophy in the Department of Pathology and Microbiology Faculty of Veterinary Medicine University of Prince Edward Island J.
    [Show full text]
  • Xenoma Formation During Microsporidial Gill Disease of Salmonids Caused by Loma Salmonae Is Affected by Host Species (Oncorhynchus Tshawytscha, O
    DISEASES OF AQUATIC ORGANISMS Vol. 48: 125–131, 2002 Published March 11 Dis Aquat Org Xenoma formation during microsporidial gill disease of salmonids caused by Loma salmonae is affected by host species (Oncorhynchus tshawytscha, O. kisutch, O. mykiss) but not by salinity J. M. Ramsay1,*, D. J. Speare1, S. C. Dawe2, M. L. Kent2,** 1Department of Pathology and Microbiology, Atlantic Veterinary College, Charlottetown, Prince Edward Island C1A 4P3, Canada 2Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia V9R 5K6, Canada ABSTRACT: Host species and salinity often affect the development of disease in aquatic species. Eighty chinook salmon Oncorhynchus tshawytscha, 80 coho salmon O. kisutch and 80 rainbow trout O. mykiss were infected with Loma salmonae. Forty of each species were reared in seawater and 40 in freshwater. The mean number of xenomas per gill filament was 8 to 33 times greater in chinook salmon than in rainbow trout (RBT). Coho salmon had a mean xenoma intensity intermediate to that of chi- nook salmon and RBT. In contrast to the differences between species, salinity had no significant effect on xenoma intensity in any of these host species. The onset of xenoma formation occurred at Week 5 postexposure (PE) for chinook salmon and RBT, and at Week 6 PE for coho salmon. RBT had cleared all visible branchial xenomas by Week 9 PE, whereas xenomas persisted in coho and chinook salmon at Week 9 PE. Histologically, xenomas were visible in the filament arteries of the branchial arch in chi- nook and coho salmon gills but were absent from RBT gills.
    [Show full text]
  • EFFECTS of TEMPERATURE on the DEWLOPMENT of LOM4 SALMONAE and RESISTANCE to RE-INFECTION in RAINBOW TROUT (Oncorhynchus Imyklss)
    EFFECTS OF TEMPERATURE ON THE DEWLOPMENT OF LOM4 SALMONAE AND RESISTANCE TO RE-INFECTION IN RAINBOW TROUT (ONCORHYnCHUS IMYKlSs) A Thesis Subrnitted to the Graduate Faculty in Partial Fulfilment of the Requirements of the Degree of Master of Science in the Department of Pathology and Microbiology Faculty of Veterinary Medicine University of Prince Edward Island Holly J. Beaman Charlottetown, PEI September 1998 01998. Holly J. Bearnan National Library Bibliothèque nationale u.1 of Canada du Canada Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 395 Wellington Street 395. rue Wellington Ottawa ON K1A ON4 OttawaON K1AON4 Canada Canada The author has granted a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distribute or sell reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfiche/nlm, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la proprieté du copy~@t in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts from it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimes - reproduced without the author's ou autrement reproduits sans son permission. autorisation. CONDITION OF USE The author has agreed that the Library, University of Prince Edward Island, may make this thesis fieely available for inspection. Moreover, the author has agreed that permission for extensive copying of this thesis for scholarly purposes may be granted by the professor or professors who supervised the thesis work recorded herein or, in their absence, by the Chairman of the Department or the Dean of the Faculty in which the thesis work was done.
    [Show full text]
  • Modes of Transmission of Loma Salmonae (Microsporidia)
    DISEASES OF AQUATIC ORGANISMS Vol. 33: 151-156. 1998 Published June 19 Dis Aquat Org ~ Modes of transmission of Loma salmonae (Microsporidia) 'Department of Zoology, 6270 University Boulevard. University of British Columbia. Vancouver, British Columbia V6T 124, Canada 2Departrnent of Fisheries and Oceans. Pacific Biological Station, Nanaimo, British Columbia V9R 5K6, Canada ABSTRACT: Loma salmonae (Putz, Hoffman and Dunbar, 1965) Morrison and Sprague, 1981 (Micro- sporidia) causes prominent gill disease in pen-reared chinook salmon Oncorhynchus tshawytscha in the Pacific Northwest. Transmission of the parasite was examined by exposing Pacific salmon Oncorhynchus spp. to infectious spores by various routes: per OS, intraperitoneal, intramuscular, and intravascular injection, by cohabitation with infected fish, and by placement of spores directly on the gill. All exposure methods led to infections except placement of spores on the gill. Putative sporoplasms were visible in epithelial cells of the alimentary canal within 24 h of per os exposure. L. salmonae may initially infect alimentary epithelia1 cells and then migrate into the lamina propria to access the blood stream. Positive results obtained by intravascular injection suggest that autoinfec.tion from spores of ruptured xeno~nasin the endothelium may also occur. The cohab~tationcxpc!r~ment demonstr~ttes that flsh may become infected by spores released from live fish. KEY WORDS: Loma salmonae Microspondia Transmission INTRODUCTION sporoplasm eventually divides, forming numerous spores within a hypertrophied cell (i.e. a xenoma) Loma salmonae (Putz, Hoffman and Dunbar, 1965) (Canning & Lom 1986). Morrison and Sprague, 1981 is a microsporidian para- Loma salmonae has been transmitted experimentally site infecting endothelial cells of salmonids.
    [Show full text]
  • University of Copenhagen, Denmark
    Impact and control of protozoan parasites in maricultured fishes Buchmann, Kurt Published in: Parasitology DOI: 10.1017/S003118201300005X Publication date: 2015 Document version Early version, also known as pre-print Citation for published version (APA): Buchmann, K. (2015). Impact and control of protozoan parasites in maricultured fishes. Parasitology, 142(special issue 01), 168-177. https://doi.org/10.1017/S003118201300005X Download date: 27. Sep. 2021 168 Impact and control of protozoan parasites in maricultured fishes KURT BUCHMANN* Laboratory of Aquatic Pathobiology, Section of Biomedicine, Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (Received 14 November 2012; revised 8 January 2013; accepted 8 January 2013; first published online 1 March 2013) SUMMARY Aquaculture, including both freshwater and marine production, has on a world scale exhibited one of the highest growth rates within animal protein production during recent decades and is expected to expand further at the same rate within the next 10 years. Control of diseases is one of the most prominent challenges if this production goal is to be reached. Apart from viral, bacterial, fungal and metazoan infections it has been documented that protozoan parasites affect health and welfare and thereby production of fish in marine aquaculture. Representatives within the main protozoan groups such as amoebae, dinoflagellates, kinetoplastid flagellates, diplomonadid flagellates, apicomplexans, microsporidians and ciliates have been shown to cause severe morbidity and mortality among farmed fish. Well studied examples are Neoparamoeba perurans, Amyloodinium ocellatum, Spironucleus salmonicida, Ichthyobodo necator, Cryptobia salmositica, Loma salmonae, Cryptocaryon irritans, Miamiensis avidus and Trichodina jadranica. The present report provides details on the parasites’ biology and impact on productivity and evaluates tools for diagnosis, control and management.
    [Show full text]
  • C:\Temp\Tevis\Final Chum Burek Wordperfect 041002 1000.Wpd
    Alaska Fisheries Technical Report Number 60 Morbidity of Tagged Wild Adult Fall Chum Salmon Captured by Fish Wheel in the Yukon River, Alaska April 2002 Region 7 U.S. Fish and Wildlife Service ! Department of the Interior Morbidity of Tagged Wild Adult Fall Chum Salmon Captured by Fish Wheel in the Yukon River, Alaska Alaska Fisheries Technical Report Number 60 by Kathy Burek, D. V. M.1 and Tevis J. Underwood 2 Key words: fall chum salmon, Oncorhynchus keta, mortality, Yukon River, fish wheel, tag, necropsy, pathology, histopathology, condition factors, hematology, Loma salmonae, Icthyophonus hoferi, Parvicapsula sp, parasites 1 Alaska Veterinary Pathology Services, 23834 The Clearing Drive Eagle River, Alaska 99577 2 U.S. Fish and Wildlife Service, Fairbanks Fishery Resource Office 101 12th Ave., Box 17, Room 222, Fairbanks, Alaska, 99701 April 2002 Disclaimers The mention of trade names or commercial products in this report does not constitute endorsement or recommendation for use by the Federal government. The U.S. Department of the Interior prohibits discrimination in programs on the basis of race, color, national origin, religion, sex, age, or disability. If you believe that you have been discriminated against in any program, activity, or facility operated by the U.S. Fish and Wildlife Service or if you desire further information please write to: U.S. Department of the Interior Office for Equal Opportunity 1849 C. Street, NW Washington, D. C. 20240 This research was funded by the U. S. Fish and Wildlife Service under contract number 70181-8-M491 to Dr. Kathy Burek, Alaska Veterinary Pathology Services, 23834 The Clearing Drive, Eagle River, Alaska 99577 The correct citation for this report is: Burek, K., and T.
    [Show full text]