Allen Samantha E, O'Toole Donal, Wood Mary E, Van Wick Peach, Parrie Lindsay E, Malmberg Jennifer L, Edwards William H
Veterinary Services, Wyoming Game and Fish Department, 1212 S. Adams St., Laramie, Wyoming 82070, USA.
Wyoming State Veterinary Laboratory, 1174 Snowy Range Rd., Laramie, Wyoming 82070, USA.
J Wildl Dis. 2025 Jan 1;61(1):199-205. doi: 10.7589/JWD-D-24-00056.
Chronic wasting disease (CWD) is a fatal neurodegenerative disease of cervids caused by an infectious misfolded protein (prion). Several members of the Cervidae, including Rocky Mountain elk (Cervus canadensis nelsoni), are susceptible to CWD. There is no evidence of complete genetic resistance to CWD; the M132L polymorphism in the elk prion protein gene influences the incubation period: longest in 132LL, intermediate in 132ML, and shortest in 132MM elk. We retrospectively analyzed six female 132LL elk housed in an environment heavily contaminated with prions to 1) document clinical outcomes and incubation periods, 2) describe PrPSc distribution and extent in tissues, and 3) characterize their histologic lesions. In five of six elk, PrPSc was detected postmortem, with a distribution pattern distinct from that of 132MM and 132ML elk; time to clinical CWD onset CWD ranged from 73 to 117 mo (6.1-9.8 yr). Although the remaining animal was observed for 220 mo (18.3 yr), PrPSc was not detected in its tissues postmortem. This study suggests that 132LL elk infected via natural exposure may live even longer with CWD than previously thought, but ultimately remain susceptible. We also report a distinct distribution of PrPSc in 132LL genotypes and highlight unusual histologic findings. Understanding the relationship between cervid genetics and CWD is of increasing importance, especially given the growing interest in leveraging genetics that delay disease onset despite not preventing infection.
慢性消耗病(CWD)是由传染性错误折叠蛋白(朊病毒)引起的鹿科动物致命性神经退行性疾病。包括落基山麋鹿(加拿大马鹿尼尔森亚种)在内的几种鹿科动物对CWD易感。没有证据表明对CWD存在完全的遗传抗性;麋鹿朊病毒蛋白基因中的M132L多态性影响潜伏期:132LL型潜伏期最长,132ML型居中,132MM型最短。我们回顾性分析了六只饲养在朊病毒严重污染环境中的雌性132LL型麋鹿,以1)记录临床结果和潜伏期,2)描述PrPSc在组织中的分布和范围,3)对其组织学病变进行特征描述。在六只麋鹿中的五只中,死后检测到PrPSc,其分布模式与132MM型和132ML型麋鹿不同;临床CWD发病时间为73至117个月(6.1 - 9.8年)。尽管对剩余一只动物观察了220个月(18.3年),但死后在其组织中未检测到PrPSc。本研究表明,经自然暴露感染的132LL型麋鹿感染CWD后的存活时间可能比之前认为的更长,但最终仍易感染。我们还报告了PrPSc在132LL基因型中的独特分布,并强调了不寻常的组织学发现。了解鹿科动物遗传学与CWD之间的关系越来越重要,特别是考虑到人们越来越有兴趣利用遗传学方法来延迟疾病发作,尽管不能预防感染。