Effect of targeted selective treatement with closantel at lambing on Haemonchus burdens on Ontario sheep farms with anthelmintic resistance

产羔时用氯氰碘灵进行针对性选择性治疗对安大略省驱虫药耐药性羊场血矛线虫负担的影响

• 批准号: 445788-2012
• 负责人: Peregrine, Andrew
• 金额: $ 1.75万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=575080
• 关键词: Effect; targeted; selective; treatement; closantel

Haemonchus contortus is increasingly being recognised as a significant constraint to sheep production on pasture in Ontario; it is a significant cause of morbidity and mortality in lambs and adult sheep from the effects of profound anaemia and hypoproteinemia. Recent work in the province has demonstrated a high prevalence of resistance in this parasite to the two most commonly used anthelmintics in sheep, i.e. resistance to ivermectin and fenbendazole has been demonstrated on >90% of tested farms. Only ivermectin is approved for use in sheep, and benzimidazoles (i.e. fenbendazole and albendazole) are only available when used in an extra label manner. No other anthelmintics are available for use in sheep in Canada. As a result, farms with multiple drug resistance have no reasonable pharmaceutical alternatives for parasite treatment. Improved control strategies are therefore urgently required. This project will define the parameters that influence the infectivity of H. contortus on pasture and thus help enhance control programs for the parasite. In addition, via a proof of concept study, the ability of closantel (a narrow-spectrum anthelmintic with activity against H. contortus, not previously used in Canada) to control drug-resistant H. contortus infections will be assessed. Since ewes are the primary source of pasture contamination with H. contortus in the spring due to the periparturient egg rise induced by lambing and lactation, two treatment strategies for ewes at lambing will be evaluated, i.e. whole flock versus targeted selective treatment of ewes. Outcomes assessment will include ability of each treatment strategy to control infection and disease in the ewes and in their lambs, and to control contamination of grazing pastures - whilst not increasing the proportion of H. contortus showing resistance to closantel. The resultant data will help to generate novel strategies for controlling drug-resistant infections and for reducing anthelmintic use on sheep farms, thus contributing to more prudent use of anthelmintics in Ontario flocks. The data will also assist in the approval of a new anthelmintic for use in sheep in Canada.

捻转血矛线虫越来越多地被认为是安大略牧场绵羊生产的一个重要限制因素;它是羔羊和成年绵羊严重贫血和低蛋白血症影响下发病和死亡的一个重要原因。该省最近的工作表明，这种寄生虫对绵羊中两种最常用的驱虫药具有很高的耐药性，即对伊维菌素和芬苯达唑的耐药性已在90%以上的受试农场得到证实。 只有伊维菌素被批准用于绵羊，苯并咪唑类（即芬苯达唑和阿苯达唑）仅在以额外标签方式使用时才可用。 在加拿大，没有其他驱虫药可用于绵羊。 因此，具有多重耐药性的农场没有合理的药物替代品来治疗寄生虫。因此，迫切需要改进控制策略。该项目将定义影响H.因此有助于加强对寄生虫的控制计划。此外，通过概念验证研究，氯氰碘柳胺（一种具有抗H。contortus，以前没有在加拿大使用），以控制抗药性H。将评估扭转感染。 由于绵羊是牧场H.由于产羔和哺乳引起的围产期产蛋上升，春季出现了扭转，将评价产羔时母羊的两种治疗策略，即全群与母羊的靶向选择性治疗。 结果评估将包括每种治疗策略控制母羊及其羔羊感染和疾病的能力，以及控制放牧牧场污染的能力，同时不增加H。扭体对氯氰碘柳胺有抗药性。 由此产生的数据将有助于产生新的策略，控制耐药感染，减少驱虫剂的使用羊场，从而有助于更谨慎地使用驱虫剂在安大略羊群。这些数据还将有助于批准一种新的驱虫剂用于加拿大的绵羊。