Chronic Wasting Disease Worldwide: 2026 Update on CWD Cases and Geographic Spread

Chronic wasting disease (CWD) continues to expand in 2026, but the global burden remains overwhelmingly concentrated in North America. As of 5 October, CWD has been documented in 37 US states and five Canadian provinces, while Norway, Sweden, Finland and South Korea remain the only other countries with confirmed infections.

United States: 37 states affected

The United States remains the global centre of CWD. By June 2026, the disease had been documented in 37 states, in free-ranging and/or captive cervids. Recent 2026 detections have continued to extend the known distribution, while long-established states such as Wisconsin, Colorado and Wyoming remain major endemic areas.

The national figure masks major local differences. Some states have only a few infected animals, whereas prevalence in long-established endemic zones can be much higher. This is why county-level surveillance is increasingly more informative than simply counting affected states.

Canada: five provinces and seven infected farmed herds in 2026

CWD has been documented in five Canadian provinces: Alberta, Saskatchewan, Manitoba, British Columbia and Quebec. Farmed-cervid surveillance also remains active. By 31 August 2026, Canada had confirmed seven infected domestic cervid herds during the year: four in Saskatchewan and three in Alberta. The affected animals included white-tailed deer and elk.

Alberta and Saskatchewan remain the main Canadian endemic areas, but detections in Manitoba and British Columbia have expanded the geographic footprint of the disease.

Norway: more than 200,000 cervids tested since 2016

Norway detected Europe's first CWD case in wild reindeer in 2016 and has since established one of the world's most intensive cervid surveillance programmes. By March 2026, Norway had tested around 200,000 cervid samples since the first detection. In 2025 alone, 11,612 animals were tested, with three CWD-positive moose identified.

Norway has identified two epidemiologically distinct patterns: contagious CWD in wild reindeer and apparently sporadic prion disease in older moose and red deer.

Sweden and Finland: rare, atypical cases

Sweden continues targeted surveillance, particularly in clinically suspicious moose. In 2025, 39 suspect moose were tested and all were negative, following earlier CWD/TSE detections in the country. Finland has recorded three cervid TSE cases: one moose in 2018, one in 2020 and one in 2022. All involved old, debilitated female moose, and Finnish authorities consider these cases biologically closer to the atypical Nordic moose form than to contagious North American CWD.

South Korea: 429 infected farmed cervids

South Korea remains the only Asian country with established CWD history. Between 2001 and 2024, 429 farmed cervids tested positive across 53 farms. Most cases involved elk, but red deer and sika deer were also affected. During the endemic phase from 2016 to 2024, 385 positives were detected among 4,010 high-risk farmed cervids tested. Importantly, surveillance of 2,867 wild cervids between 2014 and 2024 found no CWD-positive animals, suggesting that the Korean problem remains centred on farmed populations.

Prevalence in South Korean farmed cervids fell below 0.5% during 2020–2024, but cases continued to occur annually, confirming persistent endemic circulation.

No confirmed human cases

Despite decades of exposure, no confirmed human infection with CWD has been identified. Public-health authorities nevertheless recommend that meat from CWD-positive animals should not be consumed.

Situation updated: 5 October 2026. Worldwide, confirmed CWD remains restricted to the United States, Canada, Norway, Sweden, Finland and South Korea, with North America accounting for by far the largest geographic and epidemiological burden.