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Title: An exploratory investigation into the genetic basis of virulence in viral haemorrhagic septiceamia virus for rainbow trout {Oncorhynchus mykiss)
Author: Campbell, Scott
ISNI:       0000 0004 2689 8437
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2009
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No abstract provided. General Introduction commences:- RNA viruses are ubiquitous throughout the marine and freshwater environment, and are the most influential pathogens encountered within salmonid culture. Ensuring successful transmission in an environment where encounter of new potential hosts may be sporadic, viruses in the aquatic environment are required to sustain their infectivity sufficiently long enough to make direct contact with and infect susceptible hosts. Infection may then remain sub-clinical in order to ensure the long term transmission of virus where host availability is limited. Indeed, surveillance of apparently healthy wild fish populations has resulted in many virus isolations which were not associated with clinical disease. The occurrence of piscine diseases caused by viruses that had previously only been isolated within asymptomatic wild populations has, however, exacerbated in recent years due to the practice of rearing fish. High stocking densities and unrestricted host-to-host spread undoubtedly favour an acute viral life strategy. Selection pressures associated with intensive fish farming have the potential to disrupt and dramatically affect the natural equilibrium between host and pathogen, with disease often being the result. Additional selection pressures include water chemistry, temperature, high stocking densities and ultimately exposure of viruses to susceptible hosts. Within an optimal environment RNA viruses are capable of achieving high mutation rates, evolving in some cases one million times faster than their respective host chromosomal DNA. Small genomes coupled with high mutation rates means these viruses are effectively subject to different evolutionary processes than DNA based organisms with larger genomes and lower rates of mutation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available