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Research project NRC-183986

Aphanomyces astaci hyphae

Hyphae of Aphanomyces astaci

Photo: Trude Vrålstad, Section of Mycology

Advanced monitoring of the introduced crayfish plague (Aphanomyces astaci) for improved management of endangered freshwater crayfish

Project abstract

Aphanomyces astaci is a specialized parasite on North American freshwater crayfish. Accidental introduction of A. astaci to Europe resulted in the lethal crayfish plague (CP). Later introductions of North American carrier crayfish to Europe has accelerated CP spread and established constant infection reservoirs. Due to CP, European freshwater crayfish are endangered, and the crayfish businesses suffer great economical losses. In Norway, CP is listed as a group A disease, and introduction of carrier crayfish is prohibited. Several outbreaks of CP have wiped out Norwegian populations of noble crayfish, and illegally introduced carrier crayfish was recently detected. Growing evidence indicate that CP may persist longer than previously thought, which complicates re-stocking activities. In

2005, CP killed reintroduced crayfish stocks in two Norwegian watercourses. Recently, the Minister of Fisheries and Coastal Affairs asked the competent authorities to develop strategies to combat CP and signal crayfish in Norway. The major objective of the proposed project is to develop and apply molecular methods for direct monitoring of A. astaci in water and environment in order to 1) explore the ecology of A. astaci in freshwater systems and 2) develop rapid, reliable and cost efficient tools for improved surveillance that will enhance sustainable management and use of freshwater crayfish. Improved surveillance will include a) early warning of CP infections, b) unveiling illegally introduced carrier crayfish and c) declare waters free of infection. The project will further explore the persistence of CP in freshwater habitats and target mechanisms for prolonged survival. Methods for monitoring high- and low virulent CP-genotypes will be developed in collaboration with active project partners. The project involves collaboration with reputed national and international institutions that will ensure needed competence, provide relevant study areas, and enhance research networking

Principal objective and sub goals

Principal objective: Develop and apply molecular methods for direct monitoring of crayfish plague (CP) in water and environment in order to 1) explore the ecology and adaptation of Aphanomyces astaci in freshwater systems and 2) develop rapid, reliable and cost efficient tools for improved management of endangered freshwater crayfish.


  • Develop an operational real-time PCR for direct and quantitative monitoring of CP in freshwater and freshwater environments
  • Sample water, sediments, potential intermediate host organisms and signal crayfish from relevant freshwater systems in Scandinavia
  • Compare the levels of CP-infection in signal crayfish stocks and their freshwater environments
  • Target potential alternate hosts for A. astaci from Nordic freshwater systems.
  • Develop molecular markers for direct monitoring and epidemiological studies of low- and high virulent CP-genotypes.
  • Determine the distribution of CP-genotypes involved in previous & present Norwegian outbreaks

Project leader

Dr. Trude Vrålstad, Section of Mycology, National Veterinary Institute, Norway and University of Oslo, Department of Biology, Microbial Evolution Research Group

Internal project partners at the National Veterinary Institute:

  • MSc. David Strand
  • Dr. Ida Skaar, Section of Mycology, Department of Feed and Food Safety
  • Dr. Arne Holst-Jensen, Section of Mycology, Department of Feed and Food Safety
  • Dr. Hildegun Viljugrein, Section of Epidemiology, Department of Health Surveillance

External national project partners:

External international project partners:

  • University of Kuopio (Finland), Department of Biosciences, Kuopio, Finland (Japo Jussila and Harri Kokko)
  • Swedish Board of Fisheries, Institute of Freshwater Research, Drotningsholm, Sweden (Lennart Edsman)
  • Finnish Food Safety Authority Evira, Kuopio, Finland (Satu Viljamaa-Dirks)
  • Charles University in Prague, Czeck Republic (Adam Petrusek)
  • Universite de Poitiers, France (Frederic Grandjean)

Funding sources

  • The Norwegian Research Council (NRC), grant number 183986
  • The National Veterinary Institute, Norway
  • The Norwegian Institute for Nature Research, Norway


Project results summarized in CRISTIN

Project report CPmonitor NFR183986 (in Norwegian)