CWD: An Overview

Chronic wasting disease (CWD) is a fatal, infectious disease of deer, elk, reindeer and moose (cervids) that affects the central nervous system. Caribou, a subspecies of reindeer in Canada, can likely also be affected.

CWD has no known cure or treatment.

An infected cervid may appear healthy for several years before it develops changes in its body and behaviour, such as weight loss, poor coordination and other signs before it dies. Infected cervids are also more prone to being killed by other means such as hunting or vehicle collisions.

CWD is a prion disease in the same family of diseases as scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle (also known as “mad cow disease”) and Creutzfeldt-Jakob disease in humans. Prions are infectious abnormal proteins that accumulate in the brain and other tissues.

CWD Discovery and Spread

CWD was first identified in a wildlife research facility in Colorado in the 1960s but was not identified as a scrapie-like disease until 1978. The disease was subsequently found in wild deer in the same area. It is speculated CWD was derived from a mutation of scrapie, which existed in the area, or the CWD prion was caused by a spontaneous mutation within a cervid.

CWD has now been found in Saskatchewan, Alberta, Quebec and Manitoba and has been detected in 29 US states. The National Wildlife Health Center’s CWD map shows affected farmed cervid herds and general regions where CWD is in the wild. CWD has also been found in South Korea and, more recently, Norway.

For additional information on CWD in Saskatchewan wild cervids, see the Canadian Wildlife Health Cooperative’s CWD page. CWD has been detected in wild cervids throughout most of the western and central portions of the province, as well as the northeastern areas around Nipawin and Carrot River. However, testing has been limited and CWD may also be present in other areas.

CWD was likely brought into Saskatchewan by importing infected elk from South Dakota in the 1980s. The disease was first detected in a Saskatchewan-farmed cervid in 1996 and in wild cervids in 2000. It has since spread to other areas of Saskatchewan through farmed and wild cervids.

CWD and Human Health

A human case of CWD has never been identified, but transmission to humans cannot be excluded.

As a precaution, Health Canada and the World Health Organization recommend that people not eat meat or other parts of a CWD-infected animal.

The Government of Canada conducts national surveillance for all human prion diseases, and reviews and monitors CWD-related scientific literature. It will provide updated recommendations and positions as new scientific evidence indicates.

Cervid Chronic Wasting Disease Surveillance Program

The Cervid Chronic Wasting Disease Surveillance Program provides surveillance to detect chronic wasting disease on domestic game farms in Saskatchewan. Early detection limits spread to other farmed cervids on the premises, to other game farms and to wild cervids, which may come into contact with affected cervids and their fluids/manure. For more information, see the chronic wasting disease overview page.

The Saskatchewan Ministry of Agriculture administers and regulates the Chronic Wasting Disease Surveillance Program under The Domestic Game Farm Animal Regulations, 2019. All domestic game farm operators that keep cervids in Saskatchewan are required to participate. The program began in January 2001 on a voluntary basis, and was made mandatory on December 31, 2001.

Chronic wasting disease is a federally reportable disease in Canada, and all suspected cases are to be reported to a Canadian Food Inspection Agency (CFIA) district veterinarian. On April 1, 2018, CFIA changed its control program so that only game farms that are on the federal Herd Certification Program (HCP) will be quarantined, depopulated and compensated. In Saskatchewan, Manitoba, Ontario and Quebec, the HCP is administered by the Canadian Sheep Federation, which manages a similar program for scrapie in sheep. Saskatchewan game farm operators interested in enrolling in the HCP can visit the Canadian Sheep Federation website. Additional information on the HCP can be found at CFIA’s chronic wasting disease webpage.

On November 15, 2019, chronic wasting disease was listed as a reportable disease under The Animal Health Act and its Regulations. All suspect or confirmed cases of are to be reported to the office of the provincial Chief Veterinary Officer within 24 hours.