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Title: Molecular epidemiology and biology of viral haemorrhagic septicaemia virus (VHSV)
Author: Snow, M.
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 1999
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This project investigated the molecular epidemiology and biology of the fish novirhabdovirus viral haemorrhagic septicaemia virus (VHSV). An RNase protection assay (RPA) was developed for the rapid classification of new isolates and selection of representatives for further more detailed analyses. RPA analyses identified the 5' portion of the N gene mRNA as a variable region which was used as the basis for classification of thirty-nine isolates of marine origin into ten RPA groups. Subsequent nucleotide sequence determination and hylogenetic analysis based on this region and the glycoprotein of VHSV revealed two main lineages of virus as circulating within Europe (genotype I-II) and an additional genotype circulating within North America (genotype III). Within Europe a link was identified between isolates recovered from the Baltic marine environment and isolates responsible for VHSV epidemics in rainbow trout farms in continental Europe (genotype I). In addition a relationship between isolates recovered from wild caught fish around the British Isles and isolates causing mortality in farmed turbot was highlighted (genotype II). This indicated that the source of VHSV in both freshwater and marine farm outbreaks of VHSV may have been the marine environment. To investigate the phenomenon, in vivo passage of a marine isolate was conducted to investigate the capacity for a marine strain of VHSV to adapt to rainbow trout. No overall change in the consensus G gene sequence was recorded following passage although some increase in virulence was observed. Whether change in virulence was due to genetic change outwith this region or to other factors, therefore remains unclarified. In this study isolates of VHSV recovered from both cod and turbot were shown to cause clinical disease in homologous species. This raises concerns over the role of VHSV in causing mortality amongst wild fish stocks, in addition to the threat presented to the future culture of these commercially important fish species.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available