Crayfish plague (Aphanomyces astaci)
The Norwegian Veterinary Institute (NVI) conducts crayfish plague surveillance in control areas, combat zones and risk areas.
The purpose of the program is to monitor the infection pressure and infection development in control areas and combat zones for Aphanomyces astaci, and to substantiate disease freedom and/or provide an early warning of possible infection spread in to risk areas
2024
This surveillance programme for Aphanomyces astaci uses environmental DNA (eDNA) monitoring for detection of A. astaci spores directly from water filtrates. The presence/absence of eDNA from noble crayfish (Astacus astacus) and signal crayfish (Pacifastacus leniusculus) is also determined to evaluate the habitat status. Detection of noble crayfish eDNA, combined with the absence of eDNA from A. astaci and signal crayfish, support the presence of non-infected noble crayfish which constitutes the desired habitat status. In 2024 eDNA from A. astaci was detected within the restriction zone in Lake Rødnessjøen in the Halden watercourse, and within the restriction zone in River Hæra. The active outbreak of crayfish plague in River Hæra spread upstream into River Dalselva during the summer, but remained within the restriction zone. Illegally introduced signal crayfish was discovered in Lake Øyern, a large lake in the Glomma watercourse, after notification from the locals. Tissue samples from the signal crayfish was analysed and confirmed A. astaci positive. Frequent detections of noble crayfish eDNA within the regulated A. astaci restriction zones of the Halden watercourse, Mosse watercourse, and the rivers Vrangselva and Finnsrudelva in Eidskog, suggest the presence of vital noble crayfish populations within A. astaci restriction zones.
Download report
- Aphanomyces astaci 2024 (pdf 4mb)
Previous reports
- Aphanomyces astaci 2023 (pdf 3mb)
- Aphanomyces astaci 2022 (pdf 4mb)
- Aphanomyces astaci 2021 (pdf 3mb)
- Aphanomyces astaci 2020 (pdf 3mb)
- Aphanomyces astaci 2019 (pdf 5mb)
- Aphanomyces astaci 2018 (pdf 8mb)
- Aphanomyces astaci 2017 (pdf 6mb)
- Aphanomyces astaci 2016 (pdf 2mb)