Dennis Michelle M, Thomsen Bruce V, Marshall Katherine L, Hall S Mark, Wagner Bruce A, Salman Mo D, Norden Dianne K, Gaiser Charles, Sutton Diane L
From the Animal Population Health Institute, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523.
Am J Vet Res. 2009 Jan;70(1):63-72. doi: 10.2460/ajvr.70.1.63.
To determine the suitability and estimate the sensitivity of an immunohistochemical (IHC) test for disease-associated prion protein (PrP(Sc)) in biopsy specimens of rectoanal mucosa-associated lymphoid tissue (RAMALT) for diagnosis of scrapie in sheep.
762 sheep at high risk for having scrapie and indemnified by the National Scrapie Eradication Program.
The IHC test for PrP(Sc) was applied to 2 RAMALT and 2 third-eyelid biopsy specimens and a postmortem RAMALT specimen from each sheep. Results were compared with those of a reference test in which results for tissues from obex and retropharyngeal lymph nodes, tonsil, or both were considered in parallel.
The reference test identified 139 sheep as having scrapie. Biopsy-related complications occurred in 3 sheep. Sensitivity of the IHC test in RAMALT ranged from 85.3% to 89.4%, depending on the anatomic location from which RAMALT was obtained. Results for the test applied to 1 RAMALT specimen were similar to results interpreted in parallel for 2 third-eyelid specimens (sensitivity, 87.0%). The proportion of inconclusive test results attributable to insufficient lymphoid follicles in biopsy specimens was lower when considering results for 2 RAMALT specimens in parallel (10.1%) than when considering results for 2 third-eyelid specimens in parallel (23.7%). Specimens of RAMALT that were inappropriately collected from an area caudal to the rectoanal interface yielded a high proportion of inconclusive results (33.3% to 50.0%).
The IHC test for PrP(Sc) in RAMALT was an effective means of detecting subclinical scrapie in live, high-risk sheep.
确定免疫组织化学（IHC）检测绵羊直肠肛门黏膜相关淋巴组织（RAMALT）活检标本中疾病相关朊病毒蛋白（PrP(Sc)）用于诊断羊瘙痒病的适用性，并评估其敏感性。
762只具有感染瘙痒病高风险且参加国家瘙痒病根除计划的绵羊。
对每只绵羊的2份RAMALT和2份第三眼睑活检标本以及1份死后RAMALT标本进行PrP(Sc)的IHC检测。将结果与参考检测结果进行比较，参考检测同时考虑延髓和咽后淋巴结、扁桃体或两者组织的检测结果。
参考检测确定139只绵羊患有瘙痒病。3只绵羊出现活检相关并发症。根据获取RAMALT的解剖位置不同，RAMALT中IHC检测的敏感性在85.3%至89.4%之间。应用于1份RAMALT标本的检测结果与同时对2份第三眼睑标本解读的结果相似（敏感性为87.0%）。当同时考虑2份RAMALT标本的结果时，活检标本中因淋巴滤泡不足导致检测结果不确定的比例（10.1%）低于同时考虑2份第三眼睑标本的结果时（23.7%）。从直肠肛门界面尾侧区域不适当采集的RAMALT标本产生不确定结果的比例很高（33.3%至50.0%）。
RAMALT中PrP(Sc)的IHC检测是检测活的高风险绵羊亚临床瘙痒病的有效手段。
