Greber D, Bearth G, Lüchinger R, Schuepbach-Regula G, Steiner A
Clinic for Ruminants, Vetsuisse-Faculty, University of Bern, 3001 Bern, Switzerland.
Veterinary Office of the canton of Grisons, 7001 Chur, Switzerland.
Vet J. 2016 Oct;216:25-32. doi: 10.1016/j.tvjl.2016.06.015. Epub 2016 Jul 4.
Virulent ovine footrot caused by Dichelobacter nodosus is an endemic disease worldwide. It is associated with severe pain, impaired animal welfare and economic losses. The competitive real-time PCR for the differentiation of virulent aprV2 and benign aprB2 strains of Dichelobacter nodosus provides an objective, rapid and sensitive diagnostic tool for footrot surveillance, especially as it enables early detection of subclinical carriers of virulent strains. The aim of this study was to evaluate the feasibility of complete elimination of Dichelobacter nodosus strains carrying the aprV2 gene from sheep flocks. The treatment protocol was based on careful removal of loose and severely overgrown claw horn, weekly stand-in foot baths of the entire flock for 10 min per sheep, using a 10% zinc sulphate disinfectant solution, clinical and PCR follow-up and isolation or culling of non-responders. Dichelobacter nodosus strains carrying the aprV2 gene were successfully eliminated from the feet of the sheep of all 28 flocks (100%) participating in the study within 6-19 weeks of weekly foot bathing. A strong correlation between the length of time for weekly foot bathing to eliminate the virulent strains and the within-flock prevalence of clinical footrot at the beginning was observed (rho, 0.68; P <0.001). A statistically significant correlation was not detected between flock size and the length of time for weekly foot bathing (rho, 0.28; P = 0.14), or the prevalence of clinical footrot at study commencement (rho, -0.04; P = 0.82), respectively. In conclusion, a complete elimination of Dichelobacter nodosus strains carrying the aprV2 gene in sheep flocks was possible with a protocol based on careful trimming, weekly stand-in foot baths, and identification of infection using a specific PCR-test and isolation or culling of non-responders.
由结节拟杆菌引起的恶性绵羊腐蹄病是一种全球性地方病。它会导致严重疼痛、损害动物福利并造成经济损失。用于区分结节拟杆菌的毒性 aprV2 菌株和良性 aprB2 菌株的竞争性实时 PCR 为腐蹄病监测提供了一种客观、快速且灵敏的诊断工具，特别是因为它能够早期检测出毒性菌株的亚临床携带者。本研究的目的是评估从羊群中完全消除携带 aprV2 基因的结节拟杆菌菌株的可行性。治疗方案基于仔细去除松动和严重过度生长的蹄角质，每周对整个羊群进行站立式药浴，每只羊药浴 10 分钟，使用 10% 的硫酸锌消毒溶液，进行临床和 PCR 随访，并对无反应者进行隔离或扑杀。在每周药浴 6 - 19 周内，参与研究的所有 28 个羊群（100%）的绵羊足部成功消除了携带 aprV2 基因的结节拟杆菌菌株。观察到每周药浴消除毒性菌株的时间长度与开始时羊群中临床腐蹄病的患病率之间存在很强的相关性（rho，0.68；P < 0.001）。分别未检测到羊群大小与每周药浴时间长度（rho，0.28；P = 0.14）或研究开始时临床腐蹄病患病率（rho，-0.04；P = 0.82）之间的统计学显著相关性。总之，基于仔细修剪、每周站立式药浴、使用特异性 PCR 检测识别感染以及对无反应者进行隔离或扑杀的方案，有可能在羊群中完全消除携带 aprV2 基因的结节拟杆菌菌株。
