Gavin Christine, Henderson Davin, Benestad Sylvie L, Simmons Marion, Adkin Amie
Department of Epidemiological Sciences, Animal & Plant Health Agency, Woodham Lane, Weybridge, KT15 3NB, United Kingdom.
Prion Research Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, United States.
Prev Vet Med. 2019 May 1;166:28-38. doi: 10.1016/j.prevetmed.2019.02.016. Epub 2019 Mar 6.
Chronic Wasting Disease (CWD) is a highly infectious, naturally occurring, transmissible spongiform encephalopathy (TSE, or prion disease) affecting many cervid species. CWD has been widely circulating in North America since it was first reported in 1967. In 2016, the first European case of prion disease in deer was reported and confirmed in Norway. There have since been several confirmed several cases in reindeer and moose and in one red deer in Norway, and recently in a moose in Finland. There is concern over the susceptibility of certain species, especially domestic livestock, to CWD. Recently, a study was presented showing transmission to cynomolgus macaques. Although preliminary, these results raise concerns that CWD may be transmissible to humans. This quantitative risk assessment estimates, by stochastic simulation, the titre of infectivity (herein referred to as "infectivity"), that would pass into the human food chain and environment (in the UK) as a result of a single CWD positive red deer passing through an abattoir, or being field dressed. The model estimated that around 11,000 mouse i.c. log ID units would enter the human food chain through the farmed route or wild route. The model estimated that there are around 83,000 mouse i.c. log ID units in a deer carcase, compared to around 22,000 in a sheep carcase infected with scrapie, mainly due to the size difference between a red deer and a sheep. For farmed deer, the model estimated that 87% of total carcase infectivity would become animal by-product category 3 material, with only 13% going to the food chain and a small amount to wastewater via the abattoir floor. For wild deer, the model estimated that on average, 85% of total carcase infectivity would be buried in the environment, with 13% going to the food chain and 2% to category 3 material which may be used as a protein source in other industries. Results indicate that if CWD was found in the UK there would be a risk of prions entering the human food chain and the environment. However, it is unclear if humans would be susceptible to CWD following consumption of contaminated meat, or what the environmental impact would be. This risk assessment highlights the need for further research in order to quantify the infectivity in all tissue types, in particular blood, gastrointestinal (GI) tract and skeletal muscle.
慢性消耗病（CWD）是一种具有高度传染性的、自然发生的、可传播的海绵状脑病（TSE，即朊病毒病），可影响多种鹿科动物。自1967年首次报告以来，CWD一直在北美广泛传播。2016年，挪威报告并确诊了欧洲首例鹿的朊病毒病病例。此后，挪威的驯鹿、驼鹿以及一头马鹿中出现了多例确诊病例，最近芬兰的一头驼鹿也出现了病例。人们担心某些物种，特别是家畜，对CWD的易感性。最近，一项研究表明CWD可传播给食蟹猴。尽管这些结果尚属初步，但引发了人们对CWD可能传播给人类的担忧。这项定量风险评估通过随机模拟估计了由于一头CWD呈阳性的马鹿经过屠宰场或野外处理而进入人类食物链和环境（在英国）的感染性滴度（在此称为“感染性”）。该模型估计，约11,000个小鼠脑内半数感染剂量单位将通过养殖途径或野生途径进入人类食物链。该模型估计，一头鹿 carcass 中的感染性约为83,000个小鼠脑内半数感染剂量单位，而感染羊瘙痒病的绵羊 carcass 中的感染性约为22,000个，主要是由于马鹿和绵羊的大小差异。对于养殖鹿，该模型估计 carcass总感染性的87%将成为动物副产品3类材料，只有13%进入食物链，少量通过屠宰场地面进入废水。对于野生鹿，该模型估计，平均而言，carcass总感染性的85%将被埋入环境，13%进入食物链，2%进入3类材料，这些材料可能在其他行业用作蛋白质来源。结果表明，如果在英国发现CWD，朊病毒有进入人类食物链和环境的风险。然而，尚不清楚人类食用受污染肉类后是否会感染CWD，以及对环境的影响会是什么。这项风险评估强调需要进一步研究，以便量化所有组织类型，特别是血液、胃肠道（GI）和骨骼肌中的感染性。
