Monitoring of chronic wasting disease (CWD) (IV)

Area of Science:

• Veterinary Medicine
• Wildlife Disease Ecology
• Prion Disease Research

Background:

• Chronic Wasting Disease (CWD) is a transmissible spongiform encephalopathy affecting cervids.
• European countries initiated CWD monitoring programs to assess disease presence and distribution.
• Previous surveillance efforts had limitations in detecting low-prevalence CWD cases.

Purpose of the Study:

• To analyze the effectiveness of CWD monitoring programs in several European countries.
• To identify new CWD occurrences and characterize disease phenotypes.
• To propose an improved framework for future CWD surveillance in Europe.

Main Methods:

• Analysis of CWD monitoring data from Norway, Sweden, Finland, Iceland, Estonia, Latvia, Lithuania, and Poland (2017-2022).
• Detection and characterization of CWD cases in reindeer, moose, and red deer.
• Genotyping of prion protein (PRNP) in affected and unaffected wild reindeer.
• Development of a stepwise framework for enhanced CWD surveillance.

Main Results:

• CWD was newly detected in Finland, Sweden, and additional areas of Norway.
• Thirteen CWD cases were found in reindeer, 15 in moose, and 3 in red deer.
• Prevalence in detected cases was below 1%; two distinct CWD phenotypes were observed.
• Significant differences in PRNP genotypes were identified between positive and negative wild reindeer.

Conclusions:

• Current CWD surveillance requires revision, including reassessing high-risk target groups and sampling methods.
• A proposed framework emphasizes expanded background surveillance, targeted ad hoc surveys, and data-driven design prevalence.
• Genotyping of all positive cases and comprehensive PRNP analysis are crucial for understanding CWD epidemiology.