Tamba Marco, Galletti Giorgio, Loda Daniela, Salvato Sara, De Nardi Marco, Boniotti Maria Beatrice
Epidemiology Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna "B. Ubertini", Bologna, Italy.
National Reference Laboratory for Bovine Tuberculosis, Department of Animal Health, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna "B. Ubertini", Brescia, Italy.
Front Vet Sci. 2025 Aug 13;12:1609526. doi: 10.3389/fvets.2025.1609526. eCollection 2025.
In this study, we present an overview of 348 Bovine Tuberculosis (bTB) breakdowns reported in Italy between January 2022 and December 2023, and declared resolved between January 2022 and February 2025. The main objective of this study is to investigate the most probable sources of these bTB breakdowns using decision tree analysis, and to compare the findings with conclusions drawn by official veterinarians. Most of the studied breakdowns (332; 95.4%) involved cattle herds only, 11 (3.1%) involved water buffalo herds only, and five (1.4%) involved multiple species. bTB was primarily detected in beef herds (82.8%), while mixed and dairy herds represented 10.3 and 6.9% of the breakdowns, respectively. In half of the breakdowns, the number of reactors was four or fewer. We also collected genotype data for 268 complex isolates from 191 (54.9%) different breakdowns. (255 isolates; 95.1%) came from 180 (94.2%) breakdowns, showing wide genetic variability. (13 isolates; 4.9%) came from 11 (5.8%) breakdowns. Finally, we investigated the probable sources of infection, considering the five most frequently proposed sources of bTB breakdowns: (i) residual infection; (ii) introduction of infected cattle from other herds; (iii) sharing of pastures with infected herds; (iv) contiguous spread from infected neighboring herds; and (v) interaction with wildlife reservoirs. For each source, a decision tree was developed, and a likelihood of infection was assigned to each end node of the trees. The analysis identified residual infection (11.2%) as the most frequent source of bTB breakdowns, followed by sharing of pastures (10.9%) and interaction with wildlife (7.2%). The introduction of infected cattle and contiguous spread from infected neighboring herds were identified as less relevant sources. These tools allowed us to identify a likely source of infection in about 26% of cases. The results of our study, although based on scientific criteria, showed poor agreement with the conclusions of the veterinary officers who conducted the breakdown investigations in the field. In our opinion, these tools, when added to the "classic" investigation methodologies, should improve their effectiveness in identifying sources of infection in bTB breakdowns in Italy, supporting the eradication of this zoonotic disease.
在本研究中,我们概述了2022年1月至2023年12月期间在意大利报告的348起牛结核病(bTB)疫情,并宣布这些疫情在2022年1月至2025年2月期间得到解决。本研究的主要目的是使用决策树分析调查这些bTB疫情最可能的来源,并将研究结果与官方兽医得出的结论进行比较。大多数被研究的疫情(332起;95.4%)仅涉及牛群,11起(3.1%)仅涉及水牛群,5起(1.4%)涉及多个物种。bTB主要在肉牛群中被检测到(82.8%),而混合群和奶牛群分别占疫情的10.3%和6.9%。在一半的疫情中,反应动物的数量为4头或更少。我们还收集了来自191起(54.9%)不同疫情的268株复合分离株的基因型数据。(255株分离株;95.1%)来自180起(94.2%)疫情,显示出广泛的遗传变异性。(13株分离株;4.9%)来自11起(5.8%)疫情。最后,我们调查了可能的感染源,考虑了bTB疫情最常被提及的五个感染源:(i)残留感染;(ii)从其他牛群引入感染牛;(iii)与感染牛群共用牧场;(iv)来自受感染相邻牛群的连续传播;以及(v)与野生动物宿主的相互作用。对于每个来源,都开发了一个决策树,并为树的每个末端节点分配了感染可能性。分析确定残留感染(11.2%)是bTB疫情最常见的来源,其次是共用牧场(10.9%)和与野生动物的相互作用(7.2%)。引入感染牛和来自受感染相邻牛群的连续传播被确定为不太相关的来源。这些工具使我们能够在约26%的病例中确定可能的感染源。我们的研究结果虽然基于科学标准,但与在实地进行疫情调查的兽医官员的结论一致性较差。我们认为,这些工具在添加到“经典”调查方法中时,应提高其在识别意大利bTB疫情感染源方面的有效性,支持根除这种人畜共患病。