DOCSLIB.ORG

TRANSMISSION FACTORS for MICROSPORIDIAL GILL [)L!SI:Laks;E: CAUSED by LOMA Jst/Ljl/Whcwvt/U

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
TRANSMISSION FACTORS for MICROSPORIDIAL GILL [)L!SI:Laks;E: CAUSED by LOMA Jst/Ljl/Whcwvt/U TRANSMISSION FACTORS FOR MICROSPORIDIAL GILL [)l!SI:LAkS;E: CAUSED BY LOMA jSt/ljL/WHCWVt/U: 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 Joy A. Becker Charlottetown, P. E. I. 2004 C 2004. J.A. Becker Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. National Library Bibliothèque nationale 1^1 of Canada du Canada Acquisitions and Acquisisitons et Bibliographic Services services bibliographiques 395 Wellington Street 395, rue Wellington Ottawa ON K1A0N4 Ottawa ON K1A 0N4 Canada Canada Your file Votre référence ISBN: 0-612-93847-6 Our file Notre référence ISBN: 0-612-93847-6 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/film, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright 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 imprimés reproduced without the author's ou aturement reproduits sans son permission. autorisation. In compliance with the Canadian Conformément à la loi canadienne Privacy Act some supporting sur la protection de la vie privée, forms may have been removed quelques formulaires secondaires from this dissertation. ont été enlevés de ce manuscrit. While these forms may be included Bien que ces formulaires in the document page count, aient inclus dans la pagination, their removal does not represent il n'y aura aucun contenu manquant. any loss of content from the dissertation. Canada Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CONDITION OF USE The author has agreed that the Library, University of Prince Edward Island, may make this thesis freely 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. It is understood that due recognition will be given to the author of this thesis and to the University of Prince Edward Island in any use of the material in this thesis. Copying or publication or any other use of the thesis for financial gain without approval by the University of Prince Edward Island and the author’s written permission is prohibited. Requests for permission to copy or to make any other use of material in this thesis in whole or in part should be addressed to: Chair of the Department of Pathology and Microbiology Faculty of Veterinary Medicine University of Prince Edward Island Charlottetown, P. E. I. Canada C1A 4P3 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. SIGNATURE PAGE(S) L u i REMOVED Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. SIGNATURE PAGES iv REMOVED ABSTRACT Loma sa/monae causes microsporidial gill disease (MGD) in farmed Pacific salmonids, Oncorhync/?us spp., resulting in respiratory distress, secondary infections and often mortality. The infection occurs in the gills and to a lesser extent in other vascularized tissues with a final development stage of a spore-laden xenoma within the endothelial and pillar cells of the gill. The overall research goal was to identify important host, parasite and environmental factors associated with the transmission of L. salmonae in rainbow trout (RBT). Environmental Factors: Water temperature is considered to be an important environmental variable in the transmission of many fish diseases. Using a cohabitation challenge model, RBT held at 19°C had the least number of days to the development of branchial xenomas compared to fish held at either 11° and 15°C and the latter two temperatures groups showed similar xenoma onset rate. A subsequent trial revealed that water temperature affects xenoma clearance and recovery time, so that as the water temperature increased, the time required for the dissolution of all branchial xenomas decreased. Additionally, a study comparing the effect of water temperature using per os and cohabitation challenge models revealed that the regulatory effects of water temperature on xenoma onset were dependent on experimental challenge model. The overall impact of water temperature was greater when RBT were per os exposed to L. salmonae compared to the cohabitation model, which exhibited a dampened temperature effect. A study manipulating flow rate revealed that RBT held in a low flow tank (0.83 L min'^) developed xenomas the fastest with consistently higher numbers of xenomas per gill arch. Host Factors: Investigations under the domain of host factors centered on the effects of various feeding rates, the dependency of fish size at the time of exposure and further studies investigating the efficacy of monensin therapy. Although feeding rate did not alter the onset or resulting intensities of branchial xenomas, fish size was found to be a significant factor. Small RBT (17 to 23 g) had significantly faster rate of xenoma development and increased xenoma intensity with the median onset time approximately 1 week sooner compared to the 2 larger size groups. Another host factor considered was the potential use of monensin therapy to treat MGD by investigating the minimum dose and treatment time required for therapeutic success. RBT treated with monensin at 1000 ppm following a per os exposure to spores showed a reduction in xenoma intensity by 69% and 85% at weeks 7 and 8 post exposure (PE), respectively, compared to the similarly exposed non-treated fish. Prophylactic treatment beginning at the time of per os exposure to spores or one week before with monensin (at 1000 ppm) reduced xenoma formation compared to fish not treated. Pathogen Factors: The third domain of the disease triad contains factors that directly involve the pathogen. A novel challenge model using only effluent water revealed thatL salmonae was transmitted to naive RBT without the need for physical contact with infectious fish. Additionaliy, none of the RBT exposed to ultraviolet light-treated, L. salmonae- infected effluent water developed xenomas. The minimum infective dose investigated for disease transmission using a cohabitation challenge model was when 5 infectious fish were cohabited with 45 naive RBT for 1 hour. The contributions contained herein were partly novel observations identifying previously unexplored transmission factors and partly studies furthering knowledge involving known transmission factors. The importance of identifying specific transmission factors that alter the disease cycle is emphasized throughout the entire thesis. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ACKNOWLEDGMENTS I gratefully acknowledge my supervisor, Dr. David Speare for his exceptional support and guidance throughout the entire program. Dr. Speare creates an enriched research environment so that his students excel further in academia than they ever imagined. I admire the integrity and honour Dr. Speare shows not only in his research but also in his relationships with colleagues, students, friends and family. I wish to thank Dr. Ian Dohoo for his encouragement and enthusiastic participation in my program. Also, I would like to extend my deepest gratitude to the other members of my supervisory committee, Drs. F. Markham, G. Conboy, D. Rainnie, S. Jones and B. Ikede for their individual leadership and direction. The technical support (and friendship) of Joanne Daley was greatly appreciated throughout the program. Thank you to the fellow graduate and summer students involved with Project Loma. Also, thank you to the Aquatic Facility Staff for their continued monitoring and maintenance of the experimental animals. Thanks to Monica Brittain, Tracey O’Flaherty, Diane Maclean and Rosemary Mclver for their administrative assistance. I acknowledge the financial support received from the Department of Pathology and Microbiology, the Atlantic Veterinary College stipend competition and Project Loma: a NSERC strategic grant. I am thankful to have met so many different and interesting people over the last five years at AVG. Special thanks goes to Nicole Buchanan, Sara Purcell, Jennifer Ramsay, Nicole MacDonald, Sandie Morrison, Holly Beaman, Debra MacDonald and Crystal Lavalleé. Thanks to my parents, Charles and Nancy for their love and support during my graduate program. Also, a special thank you to my sister, Melissa for encouraging me to move to PEI and for her friendship. Thanks to the other members of my family, Tim, Laurie and Colin for all their support and for saving my place at Christmas dinner. I would like to acknowledge the greatest study partner. Mocha, for staying up late with me and for keeping her paws off my notes. Finally, I would like to thank
Load more

Recommended publications
  • Effects of Loma Morhua (Microsporidia) Infection on the Cardiorespiratory Performance of Atlantic Cod Gadus Morhua (L)
    Journal of Fish Diseases 2015 doi:10.1111/jfd.12352 Effects of Loma morhua (Microsporidia) infection on the cardiorespiratory performance of Atlantic cod Gadus morhua (L). M D Powell1 and A K Gamperl2 1 Norwegian Institute for Water Research, Bergen, Norway 2 Department of Ocean Sciences, Memorial University of Newfoundland, St. John’s, NF, Canada Abstract Introduction The microsporidian Loma morhua infects Atlantic Microsporidial diseases pose significant challenges cod (Gadus morhua) in the wild and in culture and to the development of marine fish aquaculture, spe- results in the formation of xenomas within the gill cifically in the North Atlantic (Murchelano, filaments, heart and spleen. Given the importance Despres-Patanjo & Ziskowski 1986; Bricknell, of the two former organs to metabolic capacity and Bron & Bowden 2006; Kahn 2009), the North thermal tolerance, the cardiorespiratory perfor- Pacific (Brown, Kent & Adamson 2010) and more mance of cod with a naturally acquired infection of recently the Red Sea (Abdel-Ghaffar et al. 2011). Loma was measured during an acute temperature Of particular significance is the infection of gadoid À increase (2 °Ch 1)from10°C to the fish’s criti- fishes [e.g. Atlantic cod (Gadus morhua)] with the cal thermal maximum (CTMax). In addition, oxy- microsporidian Loma morhua; this species is gen consumption and swimming performance were recently identified separately from Loma branchialis measured during two successive critical swimming (Brown et al. 2010). Microsporidian xenomas are ° speed (Ucrit)testsat10 C. While Loma infection characterized by their distinct morphology, with had a negative impact on cod cardiac function at those produced by Loma sp.
    [Show full text]
  • Pseudoloma Neurophilia: Progression of Infection and Transmission Characteristics of a Microsporidian Parasite in a Model Vertebrate, Danio Rerio
    AN ABSTRACT OF THE DISSERTATION OF Justin L. Sanders for the degree of Doctor of Philosophy in Microbiology presented on September 3, 2013. Title: Pseudoloma neurophilia: Progression of Infection and Transmission Characteristics of a Microsporidian Parasite in a Model Vertebrate, Danio rerio Abstract approved:________________________________________________________ Michael L. Kent The microsporidian parasite, Pseudoloma neurophilia, is the most commonly diagnosed infectious disease in laboratory populations of the zebrafish, Danio rerio. Infections by P. neurophilia are generally subclinical, however, they can become acute either incidentally or due to experimental immune suppression. Non-protocol induced variation can confound results in laboratory experiments using such fish. As a result, there has been growing interest in sensitive diagnostic assays for P. neurophilia and demand for P. neurophilia specific-pathogen free zebrafish lines among the zebrafish research community. The high prevalence of P. neurophilia in zebrafish provides the opportunity to investigate the progression of infection and transmission characteristics of a microsporidian parasite in a well-developed model vertebrate host species. I developed a real-time PCR-based assay combined with the use of sonication to improve spore disruption which has a sensitivity that is 10-100 times more sensitive than a previously published conventional PCR-based assay. The microsporidium infects ovaries and eggs, thus, I developed a sampling method for the testing of water from spawning fish and demonstrated the utility of testing spawn water, eggs, and sperm for the non-lethal detection of P. neurophilia in adult fish. The presence of P. neurophilia in spawn water and eggs from infected adults provided the initial evidence of vertical transmission of P.
    [Show full text]
  • Gadus Morhua) M O'neill, a Frenette, R O'keefe, G Har Ri Son, S Neil, E Trippel, T Benfey and M Duffy ·······13
    Bulletin de l'Association aquacole du Canada 109-1 Vous pouvez recevoir le Bulletin en vous y abonnant pour la somme de 60$ par ann6e ou en devenant membre de l'Association aquacole du Canada (AAC), organisme d but non lucratif. Pour de plus amples renseignements, communiquez avec I'Association aquacole du Canada, 16 Lobster Lane, St-Andrews Q.,louveau-Brunswick), Canada E5B 3T6 [t61.: 506 529-4766; t6l6c.: 506 529-4609; courri61.: [email protected]; site Internet: http://www. aquacultureassociation.ca]. La cotisation s'6ldve d 60$ par personne (40 S pour les 6tudiants et les retrait6s) et 95$ pour les soci6t6s. Le quart de cette cotisation sert d couvrir le prix de l'abonnement at Bulletin. Le Bulletin est r6pertori6 dans l'Aquatic Sciences and Fisheries Abstracts (ASFA), le FISHLIT, le CAB Ab- stracts et le Zoological Record. Envoi de publication Enregistrement n' 40065445. Tout changement d'adresse doit Ctre notifr6 d l'AAC. En cas de non-livraison, pridre de retourner d 1 'AAC. Port de retour pay6. ISSN 0840-s417 Imprim6 par Taylor Printing Group Inc., Fredericton, N-B Dirigeants Tim Jackson, Pr6sident C6line Audet, Pr6sident d6sign6 Joy Wade, Vice pr6sidente Shelly King, Secr6taire Caroline Graham, Tr6sorier Membres du conseil d'administration Tillmann Benfey, Gregor Reid, Grant Vandenberg, Matthew Liutkus, Kathy Brewer-Dalton R6daction du Bulletin Susan Waddy Bulletin of the Aquaculture Association of Canada 109-1 The Bulletin is available through subscription ($60 per year) or as a benefit of membership in the Aquaculture Association of Canada, a nonprofit charitable organization. For membership information con- tact: Aquaculture Association of Canada, 16 Lobster Lane, St.
    [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]
  • New Microsporidia, Glugea Sardinellensis N Sp (Microsporea
    Acta Protozool. (2016) 55: 281–290 www.ejournals.eu/Acta-Protozoologica ACTA doi:10.4467/16890027AP.16.028.6097 PROTOZOOLOGICA New Microsporidia, Glugea sardinellensis n. sp. (Microsporea, Glugeida) Found in Sardinella aurita Valenciennes, 1847, Collected off Tunisian coasts Lamjed MANSOUR1,2,3,*, Aouatef THABET2,3, Abdel Halim HARRATH1, Suliman Y. AL OMAR1, Ahmed MUKHTAR1, Shaban R. SAYED4 and Abdel-Azeem Sh. ABDEL-BAKI1,5 1 Zoology Department, College of Science, King Saud University, Saudi Arabia, P.O. Box 2455, Riyadh 11451, Saudi Arabia; 2 Unité de Recherche de Biologie intégrative et Ecologie évolutive et Fonctionnelle des Milieux Aquatiques, Département de Biologie, Faculté des Sciences de Tunis, Université de Tunis El Manar, Tunisia; 3 Faculté des Sciences de Gabes, Université de Gabès, Cité Erriadh 6072 Zrig Gabès Tunisia; 4 Transmission Electron Microscope Unit, Research Centre, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia; 5 Zoology Department, Faculty of Science, Beni-Suef University, Egypt. Abstract. A new microsporidia Glugea sardinellensis n. sp. found in the teleost fish Sardinella aurita Valenciennes collected from the Tunisian coasts. The parasite develops in a large xenomas measuring 1–16 mm in diameter and is generally visible with naked eye in the connective tissue around the pyloric caeca of the host. Xenoma were often rounded, but would be occasionally ovoid or irregular shape, generally creamy but rarely opaque, and filled with mature spores. The spores were unikaryotic pyriform measuring 5–5.5 (5.25±0.24) µm in length and 2.5–3 (2.75±0.24) µm in width. The posterior vacuole was large and occupied more than half of the spore.
    [Show full text]
  • Ultrastructural Details of the Xenoma of Loma Myrophis (Phylum Microsporidia) and Extrusion of the Polar Tube During Autoinfection
    DISEASES OF AQUATIC ORGANISMS Vol. 54: 203–207, 2003 Published April 24 Dis Aquat Org Ultrastructural details of the xenoma of Loma myrophis (phylum Microsporidia) and extrusion of the polar tube during autoinfection E. Matos1,L. Corral2, 3, C. Azevedo2, 3,* 1Department of Animal Biology, Federal Rural University of the Amazonia, Belém, Brazil 2Department of Cell Biology, Institute of Biomedical Sciences, and 3CIIMAR — Centre for Marine and Environmental Research, University of Oporto, Lg. Abel Salazar no. 2, 4099-003 Porto, Portugal ABSTRACT: Xenomas of the recently described new microsporidian species Loma myrophis para- sitizing the gut tissue of the Amazonian fish Myrophis platyrhynchus (family Ophichthidae) were described by light- and transmission-electron microscopy. The xenoma consisted of a thin fibrillar wall that surrounded a hypertrophic host cell cytoplasm containing numerous microsporidian devel- opmental stages and spores. Several spores showed different stages of natural extrusion of the polar tube. Numerous longitudinal and transverse sections of the extruded polar tubes were observed in developing life-cycle stages (spores excepted), the nucleus of hypertrophic host cell, the xenoma wall and surrounding fibroblasts. The extruded polar tubes were projected in all directions with no preferential orientation. These aspects suggested that autoinfection occurred within this xenoma. KEY WORDS: Ultrastructure · Microsporidian · Xenoma · Extrusion · Polar tube · Loma myrophis · Parasite Resale or republication not permitted without written consent of the publisher INTRODUCTION very few cases of autoinfection involving the extrusion of polar tubes have been observed, with extruded tubes A common reaction of hosts to invasion by a reported only once within fish xenomas (Lom & microsporidia is their laying down of membranes and Pekkarinen 1999).
    [Show full text]
  • Experimental Horizontal Transmission of Enterospora Nucleophila (Microsporea: Enterocytozoonidae) in Gilthead Sea Bream (Sparus Aurata)
    animals Article Experimental Horizontal Transmission of Enterospora nucleophila (Microsporea: Enterocytozoonidae) in Gilthead Sea Bream (Sparus aurata) Amparo Picard-Sánchez 1, M. Carla Piazzon 1 , Itziar Estensoro 1 , Raquel Del Pozo 1, Nahla Hossameldin Ahmed 2 , Oswaldo Palenzuela 1 and Ariadna Sitjà-Bobadilla 1,* 1 Fish Pathology Group, Instituto de Acuicultura Torre de la Sal (IATS-CSIC), 12595 Ribera de Cabanes, Spain; [email protected] (A.P.-S.); [email protected] (M.C.P.); [email protected] (I.E.); [email protected] (R.D.P.); [email protected] (O.P.) 2 National Institute of Oceanography and Fisheries, NIOF, Cairo 11562, Egypt; [email protected] * Correspondence: [email protected]; Tel.: +34-964319500 Simple Summary: Enterospora nucleophila is a microsporidian parasite infecting gilthead sea bream (Sparus aurata) that has been associated with increased mortality, growth arrestment and emaciation in aquaculture settings. The investigations on this parasite depend on material from spontaneous outbreaks in fish farms, which hampers advancements in infection research and control. In the present study, different ways of horizontal transmission were performed in order to establish an in vivo transmission model. Parasite transmission was achieved with all the assayed routes, but with milder clinical signs than in natural infections. Citation: Picard-Sánchez, A.; Piazzon, M.C.; Estensoro, I.; Del Pozo, Abstract: Enterospora nucleophila is a microsporidian enteroparasite that infects mainly the intestine R.; Hossameldin Ahmed, N.; of gilthead sea bream (Sparus aurata), leading to an emaciative syndrome. Thus far, the only available Palenzuela, O.; Sitjà-Bobadilla, A. information about this infection comes from natural outbreaks in farmed fish.
    [Show full text]
  • Transmission of Loma Salmonae (Microsporea) to Chinook Salmon in Sea Water Michael L
    Transmission of Loma salmonae (Microsporea) to chinook salmon in sea water Michael L. Kent, Sheila C. Dawe, David J. Speare Abstract poissons devraient considerer cette possibilite lors de Transmission studies were conducted to determine if l'elaboration et de l'implantation de leur plan Loma salmonae was transmissible in sea water. strategique pour controler les infections. Transmission of L. salmonae to chinook salmon (Traduit par Dr Therase Lanthier) (Oncorhynchus tshawytscha) held in sea water was achieved by exposing fish to macerated, infected gill Can VetJ 1995; 36: 98-101 tissue. Fish were exposed in seawater in a flow- through aquarium, and the infection was detected as Introduction soon as 5 wk after exposure. Heavily infected fish L oma (formerly Pleistophora) salmonae infects the exhibited numerous xenomas in the branchial arter- gills and other vascularized tissues of wild and ies, central venous sinusoids, and within the blood hatchery-reared salmonids in fresh water throughout channels of the lamellae. The pathological changes the Pacific Northwest (1-7). Severe gill infections were similar to those seen in pen-reared salmon with have been reported in rainbow and steelhead trout L salmonae infections. The infection was not observed (Oncorhynchus mykiss) and kokanee salmon (0. nerka) in Atlantic salmon (Salmo salar), Pacific herring (1). Hauck (4) observed high mortality in chinook (Clupea pallasi, family Clupeidae), or shiner perch salmon (0. tshawytscha) due to systemic infections by (Cymatogaster aggregata, family Embiotocidae), a Loniia sp. (presumably L. salmonae). Although the experimentally exposed using identical methods. gill is the primary site of infection, parasites and asso- This study suggests that L.
    [Show full text]
  • Ultrastructure and Phylogeny of Pleistophora Beebei Sp. Nov
    Acta Protozool. (2016) 55: 259–268 www.ejournals.eu/Acta-Protozoologica ACTA doi:10.4467/16890027AP.16.022.6009 PROTOZOOLOGICA Ultrastructure and Phylogeny of Pleistophora beebei sp. nov. (Microsporidia) Infecting the Amazonian Teleostean Brachyhypopomus beebei (fam. Hypopomidae) Graça CASAL1,2, Edilson MATOS3, Sónia ROCHA2,4, José SINDEAUX-NETO3, Saleh AL-QURAISHY5, Carlos AZEVEDO2,4,5 1 Department of Sciences, University Institute of Health Sciences (IUCS), CESPU, Gandra, Portugal; 2 Laboratory of Animal Pathology, Interdisciplinary Centre for Marine Environmental Research (CIIMAR/UP), University of Porto, Porto, Portugal; 3 Carlos Azevedo Research Laboratory, Federal Rural University of Amazonia, Belém (Pará), Brazil; 4 Laboratory of Cell Biology, Institute of Biomedical Sciences (ICBAS/UP), University of Porto, Portugal; 5 Zoology Department, College of Science, King Saud University, Riyadh, Saudi Arabia Abstract. A new microsporidian, Pleistophora beebei sp. nov., parasitizing the freshwater benthopelagic teleostean fishBrachyhypopomus beebei Schultz, 1944 (fam. Hypopomidae) collected from the Amazon River is described based on molecular and morphological studies. The parasite develops in the skeletal muscle of the abdominal cavity, forming a whitish cyst-like containing several groups of two types of spores (macrospores and microspores), which were observed in close contact with the myofibrils. Small groups of macrospores (ovoid elongate, tapering more anteriorly than posteriorly and measuring about 7.8±0.4 × 4.7±0.2 µm) were observed among the numerous micro- spores (lightly pyriform to ellipsoidal with rounded ends, measured about 4.7±0.3 × 2.8±0.4 µm). Both types of spores possessed a single large posterior vacuole containing flocculent material. The ultrastructural aspects observed, together with the formation of a cyst-like, sug- gest that the parasite belongs to the genus Pleistophora.
    [Show full text]
  • Review of the Sequential Development of Loma Salmonae (Microsporidia) Based on Experimental Infections of Rainbow Trout (Oncorhynchus Mykiss) and Chinook Salmon (O
    FOLIA PARASITOLOGICA 52: 1–10,63–68, 2005 2005 REVIEW ARTICLE Review of the sequential development of Loma salmonae (Microsporidia) based on experimental infections of rainbow trout (Oncorhynchus mykiss) and Chinook salmon (O. tshawytscha) Michael L. Kent1 and David J. Speare2 1Center for Fish Disease Research, Department of Microbiology, 220 Nash Hall, Oregon State University, Corvallis, Oregon 97331–3404, USA; 2Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 1A 4P3, Canada Key words: Microsporidia, Loma salmonae, rainbow trout, Chinook salmon, Oncorhynchus mykiss, Oncorhynchus tshawytscha Abstract. Loma salmonae (Putz, Hoffman et Dunbar, 1965) is a common gill parasite of salmonids, and essentially all species in the genus Oncorhynchus are susceptible. Infections occur in both fresh and salt water. Loma salmonae is directly transmissible by ingestion of spores or infected tissue. The parasite infects the wall of blood vessels of various organs, but the gill is the pri- mary site of infection. Initial infection occurs in the intestine, and xenomas are easily detected in the gills by standard histology at 4–6 wk post-exposure. A few presporogonic stages of the parasite are found in the heart endothelium prior to xenoma formation in the gills. Ultrastructure studies of early infections demonstrated that wandering blood cells transport the meronts to the gills, and that merogony occurs in pillar cells and other cells underlying the gill endothelium. Xenomas develop in these cells, resulting in hypertrophied host cells filled with spores. Xenomas ultimately rupture, and are associated with severe inflammation in which free spores are found in macrophages. The parasites are most pathogenic during this phase of the infection, resulting in severe vasculitis and clinical disease.
    [Show full text]
  • Ultrastructural Evidence of Autoinfection in the Gills of Atlantic Cod Gadus Morhua Infected with Loma Sp
    DISEASES OF AQUATIC ORGANISMS Vol. 57: 227–230, 2003 Published December 29 Dis Aquat Org Ultrastructural evidence of autoinfection in the gills of Atlantic cod Gadus morhua infected with Loma sp. (phylum Microsporidia) Luis E. Rodriguez-Tovar1, Dorota W. Wadowska2, Glenda M. Wright 3, David B. Groman4,*, David J. Speare4, Darryl S. Whelan5 1Department of Pathology, College of Veterinary Medicine, Autonomous University of Nuevo Leon, CP 64930 Monterrey, Mexico 2Electron Microscopy, 3Department of Biomedical Sciences, and 4Aquatic Diagnostic Services, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island C1A 4P3, Canada 5Newfoundland Department of Fisheries and Aquaculture, St. John’s, Newfoundland A1B 4J6, Canada ABSTRACT: Infection by a microsporidian of the genus Loma was found in gills of cod Gadus morhua. Xenomas contained parasites in multiple stages of development. Some spores looked empty and had everted polar tubes, which were either straight or coiled. These polar tubes were scattered throughout the xenoma cytoplasm, and some of them pierced the plasma membrane. Those outside of the xenoma penetrated neighboring cells, including blood cells. These observations suggest that a mechanism of autoinfection could occur in blood cells and gill tissue, perpetuating the disease in the host. KEY WORDS: Ultrastructure · Microsporidia · Xenoma · Everted polar tube · Autoinfection · Loma sp. · Cod Resale or republication not permitted without written consent of the publisher INTRODUCTION Tovar et al. 2002). The rupture mechanism of xenoma and infection of new fish was described by Speare et Microsporidians belonging to the genus Loma are al. (1998). Apparently healthy fish, however, have intracellular spore-forming parasites characterized by been reported to contain intact xenomas in gills the formation of xenomas.
    [Show full text]
  • A Severe Microsporidian Disease in Cultured Atlantic Blue N Tuna
    A Severe Microsporidian Disease in Cultured Atlantic Bluen Tuna (Thunnus thynnus L.) Alejandro López-Verdejo ( [email protected] ) Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia https://orcid.org/0000-0003-1395-0278 Francisco E. Montero Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia Fernando De la Gándara Instituto Espanol de Oceanograa Centro Oceanograco de Murcia Miguel A. Gallego Instituto Espanol de Oceanograa Centro Oceanograco de Murcia Aurelio Ortega Instituto Espanol de Oceanograa Centro Oceanograco de Murcia Juan Antonio Raga Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia José F. Palacios-Abella Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia Research Keywords: Microsporidia, Marinosporidia, Glugeida, Glugea thunni new taxa, aquaculture, Osteichthyes, Scombridae, xenoma. Posted Date: April 7th, 2021 DOI: https://doi.org/10.21203/rs.3.rs-389325/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Page 1/16 Abstract One of the most promising aquaculture species is the Atlantic bluen tuna ( Thunnus thynnus ) with high market value; disease control is crucial to prevent and reduce mortality and monetary losses. Microsporidia Balbiani, 1882 (Fungi) are a potential source of damage to bluen tuna aquaculture. A new microsporidian species is described from farmed bluen tunas from the Spanish Mediterranean. This new pathogen is described in a juvenile associated with a highly severe pathology of the visceral cavity. Whitish xenomes from this microsporidian species were mostly located at the caecal mass and ranged from 0.2 to 7.5 mm. Light and transmission electron microscopy of the spores revealed mature spores with an average size of 2.2 × 3.9 μm in size and a polar lament with 13–14 coils arranged in one single layer.
    [Show full text]