Original Research ARTICLE
High-load reovirus infections do not imply physiological impairment in salmon
- 1Faculty of Land and Food Systems, University of British Columbia, Canada
- 2Department of Zoology, University of British Columbia, Canada
- 3Department of Fisheries and Oceans (Canada), Canada
The recent ubiquitous detection of PRV among salmonids has sparked international concern about the cardiorespiratory performance of infected wild and farmed salmon. Piscine orthoreovirus (PRV) has been shown to create substantial viremia in salmon by targeting erythrocytes for principle replication. In some instances, infections develop into heart and skeletal muscle inflammation (HSMI) or other pathological conditions affecting the respiratory system. Critical to assessing the seriousness of PRV infections are controlled infection studies that measure physiological impairment to critical life support systems. Respiratory performance is such a system and here multiple indices were measured to test the hypothesis that a low-virulence strain of PRV from Pacific Canada compromises the cardiorespiratory capabilities of Atlantic salmon. Contrary to this hypothesis, the oxygen affinity and carrying capacity of erythrocytes was unaffected by PRV despite the presence of severe viremia, minor heart pathology and transient cellular activation of antiviral response pathways. Similarly, PRV-infected fish had neither sustained nor appreciable differences in respiratory capabilities compared with control fish. The lack of functional harm to salmon infected with PRV in this instance highlights that, in an era of unprecedented virus discovery, detection of viral infection does not necessarily imply bodily harm and that viral load is not always a suitable predictor of disease within a host organism.
Keywords: Piscine orthoreovirus (PRV), Salmon, aerobic performance, heart inflammation, Viremia, Nucleated erythrocytes
Received: 31 Aug 2018;
Accepted: 30 Jan 2019.
Edited by:Leonardo J. Magnoni, Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Portugal
Reviewed by:Mikko J. Nikinmaa, University of Turku, Finland
Carlo C. Lazado, Norwegian Institute of Food, Fisheries and Aquaculture Research (Nofima), Norway
Copyright: © 2019 Zhang, Polinski, Morrison, Brauner, Farrell and Garver. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Mark Polinski, Department of Fisheries and Oceans (Canada), Ottawa, Canada, Mark.Polinski@dfo-mpo.gc.ca