Managing and controlling the spread of diseases in wild animal populations is challenging, especially for social and mobile species. Effective management benefits from information about disease susceptibility, allowing limited resources to be focused on areas or populations with a higher risk of infection. Chronic wasting disease (CWD), a transmissible spongiform encephalopathy that affects cervids, was detected in Colorado in the late 1960s. CWD was detected in Illinois and Wisconsin in 2002 and has since spread through many counties. Specific nucleotide variations in the prion protein gene (PRNP) sequence have been associated with reduced susceptibility to CWD in white-tailed deer. Though genetic resistance is incomplete, the frequency of deer possessing these mutations in a population is an important factor in disease spread (i.e. herd immunity). In this study we sequenced 625 bp of the PRNP gene from a sampling of 2433 deer from Illinois and Wisconsin. In north-central Illinois where CWD was first detected, counties had a low frequency of protective haplotypes (frequency <0.20); whereas in northwestern Illinois counties, where CWD cases have only more recently been detected, the frequency of protective haplotypes (frequency >0.30) was much higher (p < 0.05). Protective haplotype frequencies varied significantly among infected and uninfected geographic areas. The frequency of protective PRNP haplotypes may contribute to population level susceptibility and may shape the way CWD has spread through Illinois. Analysis of PRNP haplotype distribution could be a useful tool to assess CWD risk and allocate resources to contain and reduce the spread of infection.

管理和控制疾病在野生动物种群中的传播具有挑战性，特别是对于社会和流动物种而言。有效的管理得益于有关疾病易感性的信息，使有限的资源集中于感染风险较高的地区或人群。1960年代后期，在科罗拉多州发现了慢性消耗性疾病（CWD），这是一种可传播的海绵状脑病，会影响子宫颈。2002年在伊利诺伊州和威斯康星州发现了CWD，此后已传播到许多县。ion病毒蛋白基因（PRNP）序列与白尾鹿对CWD的敏感性降低有关。尽管遗传抗性不完全，但是在种群中具有这些突变的鹿的发生频率是疾病传播（即畜群免疫力）的重要因素。在这项研究中，我们对来自伊利诺伊州和威斯康星州的2433头鹿进行了625 bp的PRNP基因测序。在伊利诺伊州中北部首次发现CWD的县，保护性单倍型的发生频率较低（频率<0.20）；而单性保护区的频率较低。而在伊利诺斯州西北部的县，最近才发现CWD病例，保护性单倍型的发生频率（> 0.30）要高得多（p <0.05）。保护性单倍型频率在感染和未感染的地理区域之间差异很大。保护性PRNP单倍型的频率可能有助于人群水平的敏感性，并可能影响CWD在伊利诺伊州的传播方式。PRNP单倍型分布的分析可能是评估CWD风险和分配资源以控制和减少感染扩散的有用工具。