Bridges Nicole, van Winden Steven
Farm Animal Health and Production Group, Pathobiology and Population Sciences, Royal Veterinary College, Hawkshead Lane, Hatfield AL9 7TA, UK.
Animals (Basel). 2021 Apr 23;11(5):1224. doi: 10.3390/ani11051224.
Enzyme-linked immunosorbent assays (ELISA) are used to screen cows for subspecies (MAP) infections, informing Johne's disease (JD) management practices in dairy herds. The causative agent of bovine tuberculosis (bTB), , and MAP share multiple antigens. Moreover, subspecies is used in the single intradermal cervical comparative tests (SICCT) that are routinely used in early detection of cows infected with bTB. Although these are different types of immune responses, potentially the SICCT may interfere with the levels of MAP antibodies. This study aimed to clarify the relationship between the SICCT-MAP milk ELISA testing interval and apparent prevalence of JD risk statuses. Data from 51 herds were used, totalling 46,738 cow observations. The Poisson models showed that MAP milk ELISA testing at 14 day intervals post-SICCT statistically significantly increased the odds of detecting JD-positive cows compared to JD testing 85+ days post-SICCT. The odds ratio (OR) started at 2.5 in the first 14 day interval post-SICCT, increasing each two-week period to an OR of 4.0 at 57-70 days, to subsequently drop. Additionally, a herd history of bTB increased the odds of detecting JD-positive cows (OR = 1.2); this was relatively limited compared to the magnitude of the post-SICCT effect.
酶联免疫吸附测定（ELISA）用于筛查奶牛是否感染副结核分枝杆菌（MAP），为奶牛场约翰氏病（JD）的管理措施提供依据。牛结核病（bTB）的病原体以及MAP具有多种共同抗原。此外，副结核分枝杆菌用于单剂量皮内颈侧比较试验（SICCT），该试验常用于早期检测感染bTB的奶牛。尽管这些是不同类型的免疫反应，但SICCT可能会干扰MAP抗体水平。本研究旨在阐明SICCT-MAP牛奶ELISA检测间隔与JD风险状态的表观患病率之间的关系。使用了来自51个牛群的数据，共计46738头奶牛的观测数据。泊松模型显示，与SICCT后85天以上进行JD检测相比，SICCT后每隔14天进行MAP牛奶ELISA检测在统计学上显著增加了检测出JD阳性奶牛的几率。优势比（OR）在SICCT后的第一个14天间隔内开始为2.5，每两周增加一次，在57-70天时达到4.0，随后下降。此外，bTB的牛群病史增加了检测出JD阳性奶牛的几率（OR = 1.2）；与SICCT后的影响程度相比，这一影响相对有限。
