Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh EH26 0PZ, Scotland, United Kingdom.
Vet Parasitol. 2012 May 4;186(1-2):10-7. doi: 10.1016/j.vetpar.2011.11.041. Epub 2011 Nov 20.
In Europe, most nematodoses are subclinical involving morbid rather than mortal effects and control is largely achieved using anthelmintics. In cattle, the genera most associated with sub-optimal performance are Ostertagia and Cooperia whereas in sheep and goats, subclinical losses are most often caused by Teladorsagia and Trichostrongylus. In some regions, at certain times, other species such as Nematodirus and Haemonchus also cause disease in sheep and goats. Unfortunately, anthelmintic resistance has now become an issue for European small ruminant producers. One of the key aims of the EU-funded PARASOL project was to identify low input and sustainable approaches to control nematode parasites in ruminants using refugia-based strategies. Two approaches to optimise anthelmintic treatments in sheep and cattle were studied; targeted treatments (TT) - whole-group treatments optimised on the basis of a marker of infection e.g. faecal egg count (FEC), and targeted selected treatment (TST) - treatments given to identified individuals to provide epidemiological and/or production benefits. A number of indicators for TT and TST were assessed to define parasitological and production-system specific indicators for treatment that best suited the regions where the PARASOL studies were conducted. These included liveweight gain, production efficiency, FEC, body condition score and diarrhoea score in small ruminants, and pepsinogen levels and Ostertagia bulk milk tank ELISA in cattle. The PARASOL studies confirmed the value of monitoring FEC as a means of targeting whole-flock treatments in small ruminants. In cattle, bulk milk tank ELISA and serum pepsinogen assays could be used retrospectively to determine the levels of exposure and hence, in the next season to optimise anthelmintic usage. TST approaches in sheep and goats examined production efficiency and liveweight gain as indicators for treatment and confirmed the value of this approach in maintaining performance and anthelmintic susceptibility in the predominant gastrointestinal nematodes. There is good evidence that the TST approach selected less heavily for the development of resistance in comparison to routine monthly treatments. Further research is required to optimise markers for TT and TST but it is also crucial to encourage producers/advisors to adapt these refugia-based strategies to maintain drug susceptible parasites in order to provide sustainable control.
在欧洲，大多数线虫病呈亚临床症状，对动物造成的影响主要是病态而非致命，主要通过驱虫药进行控制。在牛中，与生长性能不佳关系最密切的属是奥斯特利希虫属和库珀虫属，而在绵羊和山羊中，亚临床损失通常是由泰里虫属和捻转血矛线虫引起的。在某些地区和特定时期，其他物种如细颈线虫属和食道口线虫属也会导致绵羊和山羊患病。不幸的是，驱虫药耐药性已成为欧洲小反刍动物生产者面临的一个问题。欧盟资助的 PARASOL 项目的主要目标之一是使用基于避难所的策略，确定控制反刍动物线虫寄生虫的低投入和可持续方法。该项目研究了两种优化绵羊和牛驱虫药治疗的方法；目标治疗（TT）——根据感染标志物（如粪便卵计数（FEC））优化的全群治疗，和目标选择性治疗（TST）——对确定的个体进行治疗，以提供流行病学和/或生产效益。评估了一些 TT 和 TST 的指标，以确定最适合 PARASOL 研究进行地区的寄生虫学和生产系统特定的治疗指标。这些指标包括小反刍动物的体重增加、生产效率、FEC、体况评分和腹泻评分，以及牛的胃蛋白酶原水平和奥斯特利希虫批量奶罐 ELISA。PARASOL 研究证实了监测 FEC 作为针对小反刍动物全群治疗的一种手段的价值。在牛中，批量奶罐 ELISA 和血清胃蛋白酶原检测可用于回顾性确定暴露水平，从而在下一个季节优化驱虫药的使用。在绵羊和山羊中，检查生产效率和体重增加作为治疗指标的 TST 方法证实了这种方法在维持主要胃肠道线虫的性能和驱虫药敏感性方面的价值。有充分的证据表明，与常规每月治疗相比，TST 方法选择耐药性的程度较低。需要进一步研究优化 TT 和 TST 的标志物，但鼓励生产者/顾问适应这些基于避难所的策略以维持对药物敏感的寄生虫也至关重要，从而提供可持续控制。
