Chronic Wasting Disease (CWD), in Norwegian called “skrantesjuke”, is a prion disease identified in the late 1960’s in North America and its slow spread across the continent has been unstoppable. Since 2016, the disease has been detected in reindeer, moose and one red deer in the Nordic countries (Norway, Sweden, Finland).
The prions that have been detected in Norwegian moose were in 2018 described as hitherto unknown prion types (Pirisinu ref). The results of a bio-assay study, which are now published in the prestigious PNAS journal, confirm that these moose were infected with previously unknown prion strains.
In addition, the study found that the prions in the Norwegian wild reindeer were not identical to the strains identified in North American cervids, even if they show many similarities.
The published article is the result of a long-term collaboration between the Norwegian Veterinary Institute, the Institute Superior of Health (ISS) in Rome (IT), the Canadian Food Inspection Agency of Ottawa (CA) and Colorado State University of Fort Collins (USA).
Use of bank vole
The characterization and comparison of the prions was possible thanks to the transmission of CWD-infection from cervids in Norway to a small rodent, known as bank vole (Myodes glareolus). This is a species that is very susceptible to prion diseases and is therefore well suited for such studies. When it comes to classifying different prion strains, inoculation of bank vole, along with genetically modified mice, is the most important tool.
Importance for how we manage the disease
The results show that in Norwegian cervids there is a variation with different strains of CWD prions.
-Since the newly identified prion strains have not previously been characterized, the information can be of great importance for how we manage the disease in cervids. This is especially true of moose strains, which do not appear to spread in the same way as wild reindeer strains. With new strains also comes the question of whether these can represent health risks for us humans, says Sylvie Benestad, prion researcher from the Norwegian Veterinary Institute.