Following the 2018 hunt, the NVI tested lymph node and brain samples for CWD from approximately 480 animals from Hardangervidda, and just under 80 animals from Nordfjella zone 2.

Target of 99 percent security

Researchers at the NVI have calculated that there is approximately 64 per cent probability that Nordfjella Zone 2 is free of CWD and about 67 per cent of Hardangervidda being free of CWD after the 2018 hunt. The Norwegian Food Safety Authority (NFSA) has set a requirement of 99 per cent before the areas are declared free of infection. The figures are based on a statistical calculation of the probability of detecting CWD cases, provided the flocks have at least four positive animals.

“Should Nordfjella zone 2 and Hardangervidda be declared free of CWD within five years, a higher hunting quota is needed in the years to come than there was in 2018. This applies in particular to bucks that are older than 2.5 years. Adult bucks have the highest risk of CWD, but at the same time a higher hunting quota of bucks is not expected to have a negative effect on stock growth for the wild reindeer herd,” explains NVI scientist and CWD coordinator Jørn Våge.

The NVI has developed advanced calculation models as tools for declaring the wild reindeer areas around Nordfjella zone 1 as free from infection, where the infected wild reindeer herd has been eliminated. The objective of the administration is to secure healthy wild reindeer and to re-establish a reindeer herd in Nordfjella zone 1. This requires healthy animals from Nordfjella zone 2 or Hardangervidda, and that there is no environmental contamination left in the area.

Nordfjella zone 2 is in a special position because of the proximity to Nordfjella zone 1 and the possibility that infection could be transferred. In their re-establishment plan, the authorities have set a premise that zone 2 must be declared uncontaminated before wild reindeer can be transferred to zone 1.

The quotas should be adjusted

By calculating the effect of alternative hunting quotas on the likelihood of an area being declared uncontaminated, the NVI can make recommendations on hunting quotas in 2019. After the hunt, the figures must be updated and the desired quota for 2020 can be adjusted. The NVI is also working on developing tests on live animals. These can eventually be a supplement to today's tests.

The model tool used in the health notification process was recently covered in the renowned scientific journal Methods in Ecology and Evolution.

After CWD was discovered in Norway in 2016, the Environment Agency, the NFSA, the Norwegian Institute for Nature Research and the NVI initiated a comprehensive mapping program to uncover any infection throughout the country. Since then, the NVI has analyzed over 63,000 samples. In 2018, a total of about 30,000 samples from cervids were analyzed.

Prion disease

CWD is a prion disease like scrapie in sheep or mad cow disease, where the misfolded protein accumulates in the brain and destroys it. The disease is 100% fatal to the individuals affected.