Bermingham Mairead L, Brotherstone Susan, Berry Donagh P, More Simon J, Good Margaret, Cromie Andrew R, White Ian Ms, Higgins Isabella M, Coffey Mike, Downs Sara H, Glass Elizabeth J, Bishop Stephen C, Mitchell Andy P, Clifton-Hadley Richard S, Woolliams John A
The Roslin Institute, Roslin Biocentre, Roslin, Midlothian EH25 9RG, UK.
Institute of Evolutionary Biology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, UK.
BMC Proc. 2011 Jun 3;5 Suppl 4(Suppl 4):S15. doi: 10.1186/1753-6561-5-S4-S15.
Here, we jointly summarise scientific evidence for genetic variation in resistance to infection with Mycobacterium bovis, the primary agent of bovine tuberculosis (TB), provided by two recent and separate studies of Holstein-Friesian dairy cow populations in Great Britain (GB) and Ireland.
The studies quantified genetic variation within archived data from field and abattoir surveillance control programmes within each country. These data included results from the single intradermal comparative tuberculin test (SICTT), abattoir inspection for TB lesions and laboratory confirmation of disease status. Threshold animal models were used to estimate variance components for responsiveness to the SICTT and abattoir confirmed M. bovis infection. The link functions between the observed 0/1 scale and the liability scale were the complementary log-log in the GB, and logit link function in the Irish population.
The estimated heritability of susceptibility to TB, as judged by responsiveness to the SICTT, was 0.16 (0.012) and 0.14 (0.025) in the GB and Irish populations, respectively. For abattoir or laboratory confirmation of infection, estimates were 0.18 (0.044) and 0.18 (0.041) from the GB and the Irish populations, respectively.
Estimates were all significantly different from zero and indicate that exploitable variation exists among GB and Irish Holstein Friesian dairy cows for resistance to TB. Epidemiological analysis suggests that factors such as variation in exposure or imperfect sensitivity and specificity would have resulted in underestimation of the true values.
在此，我们共同总结了两项近期分别针对英国（GB）和爱尔兰荷斯坦-弗里生奶牛群体的研究提供的科学证据，这些证据涉及牛结核病（TB）的主要病原体牛分枝杆菌感染抗性的基因变异。
这些研究对每个国家的现场和屠宰场监测控制项目存档数据中的基因变异进行了量化。这些数据包括单次皮内比较结核菌素试验（SICTT）的结果、屠宰场对结核病病变的检查以及疾病状态的实验室确认。使用阈值动物模型来估计对SICTT反应性和屠宰场确诊的牛分枝杆菌感染的方差成分。在英国，观察到的0/1量表与易感性量表之间的链接函数是互补对数-对数函数，而在爱尔兰群体中是对数链接函数。
根据对SICTT的反应性判断，英国和爱尔兰群体中结核病易感性的估计遗传力分别为0.16（0.012）和0.14（0.025）。对于屠宰场或实验室确诊的感染，英国和爱尔兰群体的估计值分别为0.18（0.044）和0.18（0.041）。
所有估计值均显著不同于零，表明英国和爱尔兰的荷斯坦-弗里生奶牛在抗结核病方面存在可利用的变异。流行病学分析表明，诸如暴露差异或灵敏度和特异性不完善等因素会导致对真实值的低估。
