Scrapie, Bovine Spongiform Encephalopathy and Chronic Wasting Disease: Current Status, Control Measures and Human Health Implications

Animal prion diseases mainly include scrapie in sheep and goats, bovine spongiform encephalopathy (BSE) in cattle, and chronic wasting disease (CWD) in cervids. Long-term epidemiological and experimental studies indicate that CWD appears non-zoonotic, whereas the zoonotic risk of scrapie remains to be fully clarified, while BSE is responsible for the emergence of a new-type human prion disease, variant Creutzfeldt–Jakob disease (vCJD). Peak BSE cases exceeded 35,000 per year in the UK during 1992–1993; vCJD peaked at 29 cases in 2000; approximately 200,000 BSE cattle have been reported worldwide; 233 vCJD cases have been recorded globally; and CWD had been detected in 36 US states and five Canadian provinces by 2025. In this review, disease histories, control and eradication measures, and current prevalences of those animal prion diseases are analyzed. Following decades of active surveillance and rigorous control measures, the potential impact of BSE on human health has been reduced to a negligible level, and the impact of scrapie on animal health has likewise remarkably decreased. Conversely, CWD displays an expanding geographical trend across North America and Northern Europe, imposing a substantial burden on animal health of both captive and free-ranging cervids.