Chronic wasting disease (CWD) of cervids (among others red deer, moose, reindeer) is a transmissible spongiform encephalopathy (TSE) similar to scrapie in small ruminants and BSE in cattle. CWD is highly contagious. Transmission occurs through numerous excretions (saliva, blood, urine, feces, etc.) already during the incubation period of infected animals. This leads to massive contamination of the environment, where the pathogen can remain infectious for decades.

CWD was first detected in Colorado/USA in the 1960s and has since spread rapidly throughout North America and Canada. In Europe, CWD was first detected in a reindeer herd in Norway in 2016. Subsequently, additional cases were detected in moose and red deer. Based on current scientific knowledge, there is no direct link between the North American and European outbreaks of CWD.