Chronic wasting disease (CWD)

What is CWD?

CWD belongs to the Transmissible Spongiform Encephalopathies (TSE) group of diseases. It is a fatal transmissible neurological disease of deer and elk that produces small lesions in brains of infected animals.

The prevalence and geographical distribution of CWD appears to be increasing in North America. Cases of CWD have also been reported in the Republic of Korea although these are probably linked to elk exported from Canada.

There have been no reported cases found in farmed or wild deer outside of North America or Korea.

Origins

The origin of CWD is unknown and the disease transmits in the absence of contaminated feed.

The precise mechanism of transmission is unclear. It is possible that the infectious agent is shed in the saliva, faeces or urine or as a result of decomposition of infected carcases and transferred to other cervids grazing the contaminated areas. It is also possible that some maternal transmission occurs.

Clinical signs

It is characterized by loss of body condition, behavioural abnormalities and death.