ELISA and fecal culture for paratuberculosis (Johne's disease): sensitivity and specificity of each method
ELISA and fecal culture for paratuberculosis (Johne's disease): sensitivity and specificity of each method
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DOI：
10.1016/s0378-1135(00)00324-2
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发表时间：
2000-12-20
影响因子：
3.3
通讯作者：
Van Tiem, J
中科院分区：
文献类型：
--
作者：
Whitlock, RH;Wells, SJ;Van Tiem, J
检测了酶联免疫吸附试验和粪便培养试验检测奶牛副结核病的敏感性和特异性。其中包括同时进行粪便培养和ELISA检测的7个奶牛群的ELISA法和粪便培养数据。以10个牛群每6个月培养一次的954头牛(其中包括697头临产成年牛)作为粪便培养敏感性测定的基础。粪便培养技术采用2g样品，采用离心法和双重培养法。在第一次牛群访问时采集的954头所有年龄段(从小牛到成人)的牛群中，79头牛的粪便培养呈阳性。在接下来的7次测试中，每隔6个月检测出另外131只动物的培养呈阳性。粪便培养检测感染牛的灵敏度在第一次采样时为38%。在697头临产牛中，67头第一次粪便培养阳性，另外91头成年牛在接下来的7次检测中培养阳性，因此在所有培养阳性的动物中，第一次培养的敏感度为42%。在被检测为受感染之前从牛群中扑杀的动物以及屠宰时粪便培养总是呈阳性的动物不包括在计算中。两组受感染的牛都会降低粪便培养的明显敏感性，与ELISA相比，同时进行粪便培养和ELISA检测的受感染奶牛群通常会产生两倍以上的培养阳性动物。根据粪便中副结核分枝杆菌脱落的程度对受感染牛进行分类有助于确定每组牛的相对比例，从而确定通过ELISA检测发现的可能性。在细菌负荷较重的动物中，即高脱落率(75%)与低脱落率(15%)相比，ELISA法具有更高的敏感性。对受感染牛群的反复检测发现，低脱落者的比例更高，更有可能成为ELISA阴性。因此，随着时间的推移，反复的牛群休息会降低酶联免疫吸附试验的灵敏度，因为大量的脱落者将首先从牛群中被淘汰。(C)，2000 Elsevier Science B.V.保留所有权利。
The sensitivity and specificity of the ELISA and fecal culture tests for paratuberculosis in dairy cattle are examined. ELISA and fecal culture data from seven dairy herds where both fecal cultures and ELISA testing was done concurrently are included. A cohort of 954 cattle including 697 parturient adults, cultured every 6 months from 10 herds followed over 4 years served as the basis to determine fecal culture sensitivity. The fecal culture technique utilized a 2 g sample with centrifugation and double incubation. Of the 954 cattle cohort of all ages (calf to adult) that were fecal sampled on the first herd visit, 79 were culture positive. An additional 131 animals were detected as culture positive over the next seven tests at 6-month intervals. The sensitivity of fecal culture to detect infected cattle on the first sampling was 38%. Of the 697 parturient cattle cohort, 67 were positive on the first fecal culture, while an additional 91 adult cattle were culture positive over the next seven tests, resulting in a sensitivity of 42% on the first culture of the total animals identified as culture positive. Animals culled from the herds prior to being detected as infected and animals always fecal culture negative with culture positive tissues at slaughter are not included in the calculations. Both groups of infected cattle will lower the apparent sensitivity of fecal culture, infected dairy herds tested concurrently with both fecal culture and ELISA usually resulted in more than twofold positive animals by culture compared to ELISA.The classification of infected cattle by the extent of shedding of Mycobacterium paratuberculosis in the feces helps define the relative proportion of cattle in each group and therefore the likelihood of detection by the ELISA test. ELISA has a higher sensitivity in animals with a heavier bacterial load, i.e. high shedders (75%) compared to low shedders (15%). Repeated testing of infected herds identifies a higher proportion of low shedders which are more likely to he ELISA negative. Thus, the sensitivity of the ELISA rest decreases with repeated herd resting over time, since heavy shedders will be culled first from the herds. (C), 2000 Elsevier Science B.V. All rights reserved.