Byrne Andrew W, Barrett Damien
One-Health Scientific Support Unit, Department of Agriculture, Food and the Marine, Agriculture House, D02 WK12 Dublin, Ireland.
Ruminant Animal Health Division, Department of Agriculture, Food and the Marine, Backweston, Co. Kildare, W23 VW2C Celbridge, Ireland.
Pathogens. 2024 Jul 22;13(7):606. doi: 10.3390/pathogens13070606.
Bovine tuberculosis (bTB) continues to have significant economic and veterinary health impacts on cattle herds where the disease remains endemic. The continual tailoring of policies to address such maintenance requires an in-depth analysis of national data, underpinning new control strategies. In Ireland, when outbreaks occur, ancillary testing of herd mates deemed to be at the highest risk of exposure to reactors is undertaken using the interferon gamma (GIF) test. This highest risk cohort was hypothesised to be of a higher future risk despite this ancillary testing. We used a dataset from Ireland to model bovine test failure to the comparative tuberculin skin test using a survival analysis (observations: 39,248). Our primary exposure of interest was whether an animal that tested negative had a GIF test after the disclosure of infection within a herd during a bTB breakdown. There was evidence that animals with a negative GIF test during a breakdown had an increased risk of failing a test relative to other animals from the same herds without this exposure. The time to failure was 48.8% (95%CI: 38.3-57.5%) shorter for the exposed group relative to the unexposed group during a two-year follow-up period (2019-2022; time ratio: 0.51; 95%CI: 0.43-0.62; < 0.001). The results from this study suggest that animals who were GIF-tested, having been deemed to have a higher risk of exposure, subsequently had shorter time-to-test failure periods. The absolute numbers of failure are small (only 2.5% of animals go on to fail during 2-year follow-up). Importantly, however, a high proportion of these high-risk herds included in the dataset failed at least one test at the follow-up (21/54 herds), impacting breakdown duration or recurrence. Such risk-informed targeting of animals could be utilised in future control policies, though further research is warranted.
牛结核病（bTB）在疾病仍然流行的牛群中继续对经济和兽医健康产生重大影响。持续调整政策以应对这种情况需要对国家数据进行深入分析，为新的控制策略提供支持。在爱尔兰，当疫情爆发时，使用干扰素γ（GIF）检测对被认为接触反应动物风险最高的同群动物进行辅助检测。尽管进行了这种辅助检测，但这一高风险群体被假设未来风险更高。我们使用来自爱尔兰的数据集，通过生存分析对牛结核菌素皮内比较试验的检测失败情况进行建模（观察值：39248）。我们感兴趣的主要暴露因素是在牛结核病疫情期间，在牛群中感染情况披露后，检测呈阴性的动物是否进行了GIF检测。有证据表明，在疫情期间GIF检测呈阴性的动物相对于同一牛群中未经历这种暴露的其他动物，检测失败的风险增加。在为期两年的随访期（2019 - 2022年）内，暴露组相对于未暴露组的检测失败时间缩短了48.8%（95%置信区间：38.3 - 57.5%）（时间比：0.51；95%置信区间：0.43 - 0.62；P < 0.001）。这项研究的结果表明，被认为暴露风险较高且接受了GIF检测的动物，随后检测失败的时间周期较短。检测失败的绝对数量较少（在两年随访期间只有2.5%的动物检测失败）。然而，重要的是，数据集中这些高风险牛群中有很大一部分在随访中至少有一次检测失败（54个牛群中有21个），影响了疫情持续时间或复发情况。这种基于风险的动物靶向策略可用于未来的控制政策，不过仍需进一步研究。
