Hibler Charles P, Wilson Kathi L, Spraker Terry R, Miller Michael W, Zink Robert R, DeBuse Linda L, Andersen Elaine, Schweitzer Darrell, Kennedy James A, Baeten Laurie A, Smeltzer John F, Salman Mo D, Powers Barbara E
Veterinary Diagnostic Laboratory, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
J Vet Diagn Invest. 2003 Jul;15(4):311-9. doi: 10.1177/104063870301500402.
Tissue samples (n = 25,050 total) from 23,256 mule deer (Odocoileus hemionus), Rocky Mountain elk (Cervus elaphus nelsoni), and white-tailed deer (Odocoileus virginianus) collected statewide in Colorado were examined for chronic wasting disease (CWD) using an enzyme-linked immunosorbent assay developed by Bio-Rad Laboratories, Inc. (brELISA), in a 2-phase study. In the validation phase of this study, a total of 4,175 retropharyngeal lymph nodes (RLN) or obex (OB) tissue samples were examined independently by brELISA and immunohistochemistry (IHC). There were 137 IHC-positive samples and 4,038 IHC-negative samples. Optical density (OD) values from brELISA were classified as "not detected" or "suspect" based on recommended cutoff values during the validation phase. Using IHC-positive cases as known CWD-infected individuals and assuming IHC-negative cases as uninfected, the relative sensitivity of brELISA depending on species ranged from 98.3% to 100% for RLN samples and 92.1% to 93.3% for OB samples; the relative specificity of brELISA depending on species ranged from 99.9% to 100% for RLN samples and was 100% for OB samples. Overall agreement between brELISA and IHC was > or = 97.6% in RLN samples and > or = 95.7% in OB samples of all species where values could be calculated; moreover, mean brELISA OD values were > or = 46X higher in IHC-positive samples than in IHC-negative samples. Discrepancies were observed only in early-stage cases of CWD. Based on the validation phase data, only RLN samples were collected for the field application phase of this study and only samples with brELISA OD values > 0.1 were examined by IHC. Among 20,875 RLN samples screened with brELISA during this second testing phase, 155 of 8,877 mule deer, 33 of 11,731 elk, and 9 of 267 white-tailed deer samples (197 total) had OD values > 0.1 and were further evaluated by IHC to confirm evidence of CWD infection. Of cases flagged for IHC follow-up, 143 of 155 mule deer, 29 of 33 elk, and all 9 white-tailed deer were confirmed positive. Mean (+/- SE) OD values for IHC-positive cases detected during the field application phase were comparable with those measured in RLN tissues during the validation phase. Based on these data, brELISA was determined to be an excellent rapid test for screening large numbers of samples in surveys designed to detect CWD infections in deer and elk populations.
在一项分两阶段进行的研究中，使用伯乐生命医学产品有限公司开发的酶联免疫吸附测定法（brELISA），对在科罗拉多州全州采集的23256只骡鹿（白尾鹿）、落基山麋鹿和白尾鹿的组织样本（共25050份）进行慢性消耗病（CWD）检测。在本研究的验证阶段，总共4175份咽后淋巴结（RLN）或延髓尾侧部（OB）组织样本通过brELISA和免疫组织化学（IHC）进行独立检测。其中有137份IHC阳性样本和4038份IHC阴性样本。在验证阶段，根据推荐的临界值，brELISA的光密度（OD）值被分类为“未检测到”或“可疑”。以IHC阳性病例作为已知感染CWD的个体，并假设IHC阴性病例未感染，brELISA针对不同物种的相对灵敏度在RLN样本中为98.3%至100%，在OB样本中为92.1%至93.3%；brELISA针对不同物种的相对特异性在RLN样本中为99.9%至100%，在OB样本中为100%。在所有可计算值的物种中，brELISA与IHC之间的总体一致性在RLN样本中≥97.6%，在OB样本中≥95.7%；此外，IHC阳性样本的brELISA平均OD值比IHC阴性样本高≥46倍。仅在CWD早期病例中观察到差异。根据验证阶段的数据，在本研究的现场应用阶段仅采集RLN样本，并且仅对brELISA OD值>0.1的样本进行IHC检测。在第二测试阶段用brELISA筛选的20875份RLN样本中，8877只骡鹿样本中的155份、11731只麋鹿样本中的33份和267只白尾鹿样本中的9份（共197份）OD值>0.1，并通过IHC进一步评估以确认CWD感染证据。在标记进行IHC后续检测的病例中，155只骡鹿中的143只、33只麋鹿中的29只和所有9只白尾鹿均被确认为阳性。现场应用阶段检测到的IHC阳性病例的平均（±标准误）OD值与验证阶段在RLN组织中测得的值相当。基于这些数据，brELISA被确定为在旨在检测鹿和麋鹿种群中CWD感染的调查中筛选大量样本的出色快速检测方法。
