EFSA 2023, Monitoring of chronic wasting disease (CWD) (IV) (EFSA Journal 21(4):e07936)

This is a scientific opinion of the EFSA Panel on Biological Hazards, published on 17 April 2023 in the EFSA Journal (DOI 10.2903/j.efsa.2023.7936), requested by the European Commission. It reviews CWD surveillance in cervids in eight European countries (Norway, Sweden, Finland, Iceland, Estonia, Latvia, Lithuania, Poland) up to 28 February 2022, describes what is new in European CWD epidemiology, proposes a future monitoring design, and sets out a genotyping approach for the prion protein gene. It is the fourth EFSA product in its CWD monitoring series, following the 2016/2017 opinion that underpinned the EU programme in Regulation 2017/1972.

Key facts

  • The Commission asked EFSA for five things by 31 March 2023: analyse the monitoring results and judge whether the 2017 objectives were met, describe new epidemiological knowledge, recommend future EU monitoring, define criteria for treating an area as not infected, and design a genotyping protocol for positive and stored negative samples.
  • The data cover eight countries and 155,660 cervids older than 12 months tested during the mandate period.
  • The opinion counts 31 confirmed cases: 13 reindeer, 15 moose and 3 red deer. By country, Norway had 25 (13 reindeer, 9 moose, 3 red deer), Sweden 4 moose and Finland 2 moose; no other country in the table had a case.
  • CWD was found for the first time in Finland and Sweden and in new parts of Norway, and red deer were identified as a newly affected species.
  • Two disease phenotypes are described: one with abnormal prion protein detectable in lymphoreticular tissue, seen so far only in wild reindeer, and one without it, seen only in moose and red deer.
  • Where cases occurred, observed prevalence was below 1 percent. Among animals hunted or slaughtered and fit for human consumption in affected areas it was about 0.05 percent in moose, 0.16 percent in red deer and 0.23 percent in reindeer.
  • Prevalence was more than ten times higher in high-risk groups for moose and red deer; road-killed animals were judged not to be a high-risk group and should be dropped from that category.
  • The two surveillance objectives (detection and prevalence estimation) were only partly met because implementation varied, and for countries with no detections the evidence was not enough to rule out CWD; only some country and species combinations reached 95 percent surveillance sensitivity.
  • EFSA proposes a stepwise framework starting with expanded minimum background surveillance in all countries with relevant cervids, plus ad hoc surveys. Criteria for declaring an area non-infected were judged not feasible, so criteria for the probability of presence are proposed instead.
  • For genotyping, all positives should be genotyped, negatives sampled at roughly 76 to 145 per country and species, the whole PRNP reading frame sequenced, and results held in a central EU system. Testing should include both retropharyngeal lymph node and brainstem.
  • The opinion rests on Regulation (EU) 2017/1972, which set a 2018 to 2020 programme for Estonia, Finland, Latvia, Lithuania, Poland and Sweden, and on the genotyping and retention provisions in Annex III of Regulation (EC) 999/2001.

Timeline

  1. 2016EFSA delivers its first opinion on CWD in cervids in the EU and EEA (2 December 2016, as stated in the background of the 2023 text).
  2. 2017Start of the mandate period analysed in the summary and terms of reference (1 September 2017); the abstract instead gives 9 January 2017.
  3. 2022End of the analysed period (28 February 2022).
  4. 2023Delivery deadline set by the Commission (31 March 2023).
  5. 2023Opinion published in the EFSA Journal on 17 April 2023.

Last checked 1 November 2026

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