Chronic Wasting Disease, affecting several cervids such as roe, red and sika deer, is classified as a Transmissible Spongiform Encephalopathy (TSE), comparable to Scrapie in small ruminants and BSE in cattle.
Causative of all TSE is the conversion of the cellular prion protein (PrPc) into a pathologic form (PrPSc) induced by PrPSc itself. The resistance of the pathological isoform against enzymatic digestion leads to a massive PrPSc deposition in the brain and thus to clinical symptoms.
CWD is a slowly progressive and always fatal disease that affects numerous cervids. To date, therapies or vaccinations are not available.
CWD is highly contagious: infectious protein is already excreted during the incubation period. Additionally it remains infectious for years in environment due to its high tenacity. This not only contributes to the rapid spread of CWD, but is also a challenge for disease control. The spread of the disease, e.g. through the importation of infected animals or animal parts, or through contaminated material such as clothing or shoes, must therefore be prevented.
CWD was first described in North America in 1967. Since then it spread across wide parts of the continent. In 2016, it was detected for the first time in Europe, in a Norwegian reindeer herd. The subsequent active surveillance program of cervids in Scandinavia led to detection of another outbreak in a geographically distant region; a clear indication that the disease has already spread in Norway.
In addition, the surveillance program also detected CWD cases in several elks and in a red deer in Scandinavia (see Figure 1). In September 2021, another red deer tested positive for CWD. However, these cases show characteristics suggesting an age-associated sporadic (atypical) form of CWD.
Based on the latest scientific results, there is no direct link between the North American and European outbreaks of CWD.
The current research project “Tackling Chronic Wasting Disease in Europe” at the FLI investigates the genetic susceptibility of our native deer species to CWD. Therefore, tissue samples from roe deer, red deer and sika deer are currently collected. Hunters, who would like to support this project, should contact Dr. Christine Fast (christine.fast@~@fli.de) or Sonja Ernst (Sonja.Ernst@~@fli.de).
Links
- Information from the Veterinary Institute of Norway www.vetinst.no
- Information in English on Chronic Wasting Disease www.hjortevilt.no
- Information on the geographical distribution of Chronic Wasting Disease www.sva.se
- First scientific opinion of the European Food Safety Authority (EFSA) Chronic wasting disease (CWD) in cervids - 2017 - EFSA Journal - Wiley Online Library
- Second scientific opinion of the European Food Safety Authority Scientific opinion on chronic wasting disease (II) | European Food Safety Authority (europa.eu)
- Third scientific opinion of the European Food Safety Authority Update on chronic wasting disease (CWD) III - 2019 - EFSA Journal - Wiley Online Library