ABSTRACT
Prion diseases, also known as transmissible spongiform encephalopathies (TSEs), are a group of rare and fatal neurological diseases [1]. Animal prion diseases include bovine spongiform encephalopathy (BSE) in cattle, chronic wasting disease (CWD) in cervids, feline spongiform encephalopathy (FSE) in cats, exotic ungulate encephalopathy (EUE) in zoo animals (e.g., kudu, nyala, gemsbok, eland, and oryx), scrapie in goats and sheep, as well as transmissible mink encephalopathy (TME) in mink (Table 14.1). The prion agent of each prion disease is named after the disease itself (e.g., CWD agent in CWD, scrapie agent in scrapie). BSE, CWD, FSE, TME, and EUE are all thought to occur after the consumption of prion-infected materials such as meat and bone meal (MBM). Among these prion diseases, BSE is a foodborne disease that affects humans. Except for BSE, no other animal prion agents have been reported to transmit to humans. Indeed, studies using transgenic mice expressing human prion protein (PrP) show that CWD prion does not transmit to humans [2–4]. Thus, the risk of CWD transmission to humans can be dismissed. However, scrapie agent has been shown to transmit via cerebral inoculation to macaque monkeys after a prolonged incubation time [5], and to transgenic mice expressing human PrP [6]. In view of these findings, further studies are clearly necessary to establish what kinds of animal prion agents can be transmitted to humans.
