Summary:
The purpose of the project is to study and to increase scientific and practical collaboration in relation to viral fish diseases particularly in farmed fish, both in Finland and abroad. While the emphasis is on IPN and VHS viruses and the perch rhabdovirus, the project also covers other viral fish diseases.
Aims:
The primary aim of the project is to promote the health and welfare of fish and to increase knowledge about the occurrence of fish viruses; factors related to such occurrences; and ways of infection. The object is to identify such new viral fish diseases that are relevant to the health and welfare of fish, and particularly farmed fish.
The IPN (infectious pancreatic necrosis) disease was found for the first time at many fish farms in the Finnish inland water area in 2012. These farms were located by the Kymijoki, Vuoksi and Kemijoki rivers. While the IPN virus is encountered yearly in the Finnish sea areas, it was very rare in the inland waterways until 2012. On the basis of these facts, IPN can be considered a fish disease threatening Finland, and it can result in significant losses to the industry. According to preliminary research, IPNV strains isolated from the Finnish inland waterways belong to genogroup 2, while virus strains of genogroups 2, 5 and 6 are encountered in sea areas. The Finnish inland waterways are free of genogroup 5 IPNV infections. Genogroup 5 IPNV is an animal disease that requires legislative control in inland water areas. Any measures taken to eradicate the disease are led by the authorities.
The purpose of the project is to determine, through viral genome sequencing, how the IPN virus spreads in Finnish inland fish farms and whether the source for the various outbreaks of disease around the country is the same, as well as to determine the relationships of IPN viruses and the epidemiology of disease outbreaks through comparison of entire genome sequences of viruses to each other and to other known IPNV strains. Infection tests are used to determine the ability of Finnish IPN virus strains to cause diseases in rainbow trout.
A rise in the mortality rate of greyling fry has been detected at two farms in the Finnish Lake District since 2002. These farms often use surface water to farm greyling fry. A virus has been isolated from 14 samples that, on the basis of sequencing the entire G gene and a partial RNA polymerase (L) gene as well as on the basis of an indirect immunofluorescence antibody test (IFAT), was classified as a perch rhabdovirus (PRV), which is a perhabdovirus. On the basis of the G and L gene sequencing, all isolated viruses were found to be almost 100% identical at both farms. The perch rhabdoviruses isolated from European perch (Perca fluviatilis) from the Baltic Sea, and from sea trout (Salmo trutta trutta) were very similar to the isolated strains. These strains are closely related to the strains isolated from perch, greyling and zander (Sander lucioperca) in France and from northern pike in Denmark. In the late 1980s, sea trout rhabdovirus – another perhabdovirus – was isolated from brown trout (Salmo trutta m. lacustris) from a fish farm in Northern Finland. The aim is to use infection tests to determine the ability of Finnish perhabdovirus strains to cause diseases.
Viral Hemorrhagic Septicaemia (VHS) in rainbow trout is a highly contagious viral disease, which causes high fish mortality rates and thus great financial losses to fish farms. In Finland, the VHS virus was isolated for the first time in 2000, from sick rainbow trout (Oncorhynchus mykiss [Walbaum]) from one food fish farm in Åland and from four farms in Pyhtää. The characteristics and epidemiology of the VHSV were studied in a project completed in 2013, ”Kalojen tarttuva verenvuotoseptikemia (VHS) Suomessa: viruskantojen tutkimus ja taudin epidemiologia kalanviljelylaitoksilla ja merialueen luonnonkaloissa VHSV” (Contagious Viral hemorrhagic septicemia [VHS] in fish in Finland: a study of viral strains and the epidemiology of the disease in farmed fish and in wild sea fish). The research on the epidemiology of VHSV strains isolated in Finland continues still.
Keywords:
virus, fish, fish farming, virus characterisation, epidemiology
Responsible project leader:
Gadd, Tuija, Head of Unit, Finnish Food Authority, Virology Unit
Persons at Finnish Food Authority responsible for the project:
Gadd, Tuija, Head of Unit, Virology Unit;
Koski, Perttu, DVM (PhD), Senior Researcher, Wild and Aquatic Animal Pathology Section
In cooperation with:
HU, Veterinärmedicinska fakulteten (prof. Liisa Sihvonen);
HU, Institutet för molekylär medicin i Finland, FIMM, (doc. Pirkko Mattila);
Danish Veterinary Laboratory;
Danmarks Tekniske Universitet;
VESO Vikan, Norja;
Prof Öysten Evensen, Norwegian University of Life Sciences, Oslo;
Luonnonvarakeskus (Luke)
Project status:
In progress
Year of commencement:
1. part 2014; 2. part 2017
Year of completion:
1. part 2016; 2. part 2021
Publications:
Anna Maria Eriksson-Kallio, Riikka Holopainen, Satu Viljamaa-Dirks, Pia Vennerström, Hanna Kuukka-Anttila, Perttu Koski, Tuija Gadd: Infectious pancreatic necrosis virus (IPNV) strain with genetic properties associated with low pathogenicity at Finnish fish farms (DAO Vol. 118: 21–30, 2016 ).
Holopainen R, Eriksson-Kallio AM, Gadd T: Molecular characterisation of Aquabirnaviruses isolated from farmed fish in Finland (manuscript).
Holopainen, R: Tarttuvaa haimakuoliotautia (IPN) aiheuttavien viruskantojen geneettinen monimuotoisuus suomalaisilla kalanviljelylaitoksilla (Eviran tiedepäivä 13.10. 2016, suullinen esitys).
Holopainen R, Eriksson-Kallio AM, Gadd T: Infectious pancreatic necrosis virus – a rising threat to fish farming in Finland? Suullinen esitys, Virology days 2015 26.-27.3.2015 Rauhalahti, Kuopio.
Holopainen R, Eriksson-Kallio AM, Gadd T: GENETIC ANALYSIS OF INFECTIOUS PANCREATIC NECROSIS VIRUSES ISOLATED IN FINLAND DURING 2000-2014. Suullinen esitys, 19th Annual Workshop of the National Reference Laboratories for Fish Diseases,27-28th May 2015.
R. Holopainen, AM Eriksson-Kallio, T. Gadd: Molecular Characterisation of Infectious Pancreatic Necrosis Viruses Isolated in Finland During 2000-2014 . Posteri, 10th International congress ESVV 2015 for veterinary virology and 9th annual meeting of Epizone 31.8-3.9.15 Montpellier, Ranska.
Gadd, T.
Fish rhabdoviruses: viral haemorrhagic septicaemia virus (VHSV) and perch rhabdovirus (PRV):
study of viral strains and the disease epidemiology in Finland.
University of Helsinki, Faculty of Veterinary Medicine, Department of Veterinary Biosciences.
Academic dissertation.
Holopainen, R. and Gadd, T.
Molecular characterisation of Finnish isolates of infectious pancreatic necrosis virus.
16th International Conference on Diseases of Fish and Shellfish, 2.6.9, 2013 Tampere, Finland.
Abstract, poster.
Gadd, T., Viljamaa-Dirks, S., Holopainen, R., Koski, P. and Jakava-Viljanen, M.
Characterization of perch rhabdovirus (PRV) in farmed grayling Thymallus thymallus.
Diseases of Aquatic Organisms Diseases of Aquatic Organisms 2013: Vol. 106, pp. 117–127.
Project financed by:
Finnish Food Authority;
Finnish Foundation of Veterinary Research;
Euroopan Meri- ja Kalatalousrahasto (EMKR)
Finnish Food Authority project code:
8258 Suomen IPNV – kannat