Control and Surveillance Operations to Prevent Chronic Wasting Disease Establishment in Free-Ranging White-Tailed Deer in Québec, Canada

SIMPLE SUMMARY: Chronic wasting disease (CWD) is a transmissible and deadly disease affecting free-ranging and farmed cervids; no treatment or vaccine is available at this time to cure or prevent CWD. When established in free-ranging cervid populations, CWD is currently impossible to eradicate and leads to potentially irreversible population declines. The first cases of CWD in Québec were detected in 2018 on a red deer (Cervus elaphus) farm. Immediately following detection, intensive culling efforts were conducted in a control area around the infected farm to (1) eliminate free-ranging deer that may have come in contact with infected deer from the farm, and (2) to decrease free-ranging deer densities to reduce potential contact between the animals and therefore lower the risk of transmission. To prevent the spread of CWD, we applied legal restrictions regarding the movement of specific anatomical parts of cervids harvested near the affected farm. To determine if CWD was present in free-ranging cervids, we tested 447 white-tailed deer (Odocoileus virginianus) harvested through sport hunting in the surveillance zone, 534 white-tailed deer culled from the control area, and 2584 white-tailed deer harvested outside the enhanced surveillance zone and control area. No positive CWD cases were found, suggesting that if the disease is present in free-ranging animals, infection rates are low, and it may still be possible to prevent its establishment in Québec. ABSTRACT: Chronic wasting disease (CWD), a degenerative and fatal prion disease affecting cervids, was detected for the first time in the province of Québec, Canada, in a red deer (Cervus elaphus) farm in the Laurentides region on 10 September 2018. To assess CWD prevalence and control the disease in the free-ranging white-tailed deer (Odocoileus virginianus) population, a response plan including enhanced surveillance, population control, regulatory measures, and public outreach was deployed by the Ministry of Forests, Wildlife, and Parks (MFFP). In the 401 km(2) white-tailed deer control area, a total of 750 free-ranging white-tailed deer were culled over 70 days, from 22 September to 15 December 2018. Of the culled deer, 534 were tested for CWD. We also tested for CWD a total of 447 white-tailed deer hunted from the enhanced surveillance zone and 2584 free-ranging white-tailed deer harvested outside this zone. Regulations were applied to prevent the spread of the disease through movements of infected animals harvested by hunters. Although no case of CWD was detected in free-ranging cervids in Québec in 2018, this does not confirm the absence of the disease in these populations. However, the results suggest that if CWD is present, few free-ranging cervids are infected, making it possible to prevent its establishment in the province of Québec.