Tranulis MA et al. 2021, Chronic wasting disease in Europe: new strains on the horizon (Acta Vet Scand 63:48)

Open-access review by nine authors from Norway, Sweden, Finland and Italy, published 25 November 2021 in Acta Veterinaria Scandinavica. It collects what was known about chronic wasting disease (CWD) in Fennoscandian deer, reindeer and moose after the first European detection in 2016: surveillance results, the culled Nordfjella reindeer population, a cluster of old moose with a different disease picture, two red deer cases, and early strain typing. Its main message is that several distinct CWD agents occur in Norway and that the European situation differs from North America. Information only, not veterinary, medical or legal advice.

Key facts

  • Citation verified: Tranulis MA, Gavier-Widen D, Vage J, Noremark M, Korpenfelt SL, Hautaniemi M, Pirisinu L, Nonno R, Lafond Benestad S; Acta Vet Scand 2021;63(1):48; review article; DOI 10.1186/s13028-021-00606-x; PMID 34823556; PMCID PMC8613970; CC BY.
  • Authors are affiliated with the Norwegian University of Life Sciences, the Norwegian Veterinary Institute, SVA and SLU in Uppsala, the Finnish Food Authority and Istituto Superiore di Sanita in Rome; the record lists no grant.
  • By March 2021 Norway had tested 127,216 cervids, including 29,143 moose (8 positive), 13,997 wild reindeer (20 positive), 46,931 semi-domesticated reindeer (none positive) and 22,675 wild red deer (2 positive).
  • Sweden reported 4 positive of 1,721 moose tested and none of 3,101 semi-domesticated reindeer; Finland reported 2 positive of 818 moose and none of 1,719 reindeer or 993 white-tailed deer. Sweden began routine sampling in 2016 and EU-regulated surveillance in 2018.
  • The Nordfjella wild reindeer outbreak began with a case found in March 2016; 18 further positives were found, 19 in total. About 2,400 animals were culled in 2018, and a further case in a wild buck on Hardangervidda in 2020 followed about 25,900 negative tests over two years.
  • The Norwegian Scientific Committee advised removing the whole population with a fallow period of at least five years; the authors call it the only known European cervid population with contagious CWD, and say the 2020 case questions the prospects of eradication in wild reindeer.
  • Adult male reindeer had about 2.7 times the odds of a positive result compared with females; PRNP alleles A and C were over-represented among positives and the B allele was under-represented. Reindeer PrPres showed a three-band pattern similar to North American isolates.
  • Fourteen moose cases were reported: 8 in Norway, 4 in Sweden and 2 in Finland, mean age 14.7 years, all over 10 years. Lymphoid tissue was negative, which the authors read as pointing to a sporadic rather than contagious origin; the pathology resembles atypical prion diseases such as Nor98 scrapie and H- and L-type BSE.
  • Two Norwegian red deer cases are described; the first (2017) was a 16-year-old animal with only the obex positive, and its blot pattern showed some similarity to cattle BSE.
  • In bank vole experiments, Norwegian reindeer isolates transmitted very inefficiently compared with Canadian CWD, while moose isolates transmitted efficiently with longer survival. The authors conclude four strains exist in Norway (two in moose, one in reindeer, one in red deer). First passage of three Norwegian isolates into humanized transgenic mice was negative at the time of writing.
  • The EU programme covered Estonia, Finland, Latvia, Lithuania, Poland and Sweden for 2018 to 2020; the earlier 2007 to 2010 survey of about 600 cervids per country sampled mainly healthy animals, and EFSA found testing higher-risk animals more informative.
  • The authors argue CWD in Europe may threaten cervid populations and pose a food-safety risk, and propose treating CWD as a family of prion diseases including atypical sporadic forms.

Timeline

  1. 2016First European CWD case found in a wild reindeer in Nordfjella, Norway.
  2. 2018Nordfjella reindeer population culled (about 2,400 animals) and carcasses incinerated; EU CWD surveillance programme starts.
  3. 2020CWD found in a wild reindeer buck on Hardangervidda after about 25,900 negative tests.
  4. 2021Review published in Acta Vet Scand 63:48.

Last checked 1 November 2026

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