Abstract Anticoagulant resistance has been present in Norway rats (Rattus norvegicus) in Hampshire and Berkshire for forty years. All first-generation anticoagulants and two of the second generation, bromadiolone and difenacoum, are resisted by rats carrying the L120Q single nucleotide polymorphism (SNP). A regulatory restriction on the use of resistance-breakers brodifacoum, difethialone and flocoumafen in the UK effectively prevented their use against Norway rats for more than 30 years. During this time, L120Q spread from original localised foci eventually to cover most of central-southern England; with other more dispersed foci elsewhere in the UK. We summarise research on L120Q Norway rats and the field performance of anticoagulant baits against them. Bromadiolone (50 ppm), difenacoum (50 ppm) and brodifacoum (23 ppm) baits were each applied on two farmsteads where it had been established that Norway rats carried the L120Q SNP. Preliminary DNA resistance tests conducted at the farms found only one of 107 rats to be susceptible and 86.9% to be homozygous resistant. The bromadiolone and difenacoum applications were either partially or wholly ineffective; brodifacoum treatments were fully effective. Quantities of active substances used varied between farms and substances; but more bromadiolone and difenacoum baits were applied than brodifacoum baits during the treatments. Results confirm the high incidence of resistance and support advice that bromadiolone and difenacoum should not be used against the L120Q SNP. Prolonged use of resisted anticoagulants has resulted in a high prevalence of homozygosity and resistance spread. Failed treatments result in prolonged feeding on anticoagulant bait and leave Norway rats alive carrying, presumably, high residues. It remains to be seen whether the use of now-permitted effective substances, and the introduction of a rodenticide stewardship regime, will curtail the spread of resistance and reduce anticoagulant residues in wildlife.

中文翻译：

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Hampshire-Berkshire 对挪威大鼠（Rattus norvegicus）中 L120Q 抗凝剂抗性的关注以及溴敌隆、地芬那古和溴敌草的田间试验

摘要 40 年来，汉普郡和伯克郡的挪威大鼠 (Rattus norvegicus) 中一直存在抗凝抗性。携带 L120Q 单核苷酸多态性 (SNP) 的大鼠可以抵抗所有第一代抗凝剂和第二代中的两种，溴敌隆和地芬那古。30 多年来，英国对使用抗阻剂 brodifacoum、difethialone 和 flocoumafen 的监管限制有效地阻止了它们对挪威大鼠的使用。在此期间，L120Q 从最初的局部焦点最终蔓延到英格兰中南部的大部分地区；与英国其他地方的其他更分散的焦点。我们总结了对 L120Q 挪威大鼠的研究以及抗凝剂对它们的现场表现。溴敌隆 (50 ppm)，difenacoum (50 ppm) 和 brodifacoum (23 ppm) 诱饵分别应用于两个农场，已确定挪威大鼠携带 L120Q SNP。在农场进行的初步 DNA 抗性测试发现 107 只大鼠中只有一只易感，86.9% 的大鼠具有纯合抗性。溴敌隆和地芬那康应用部分或完全无效；brodifacoum 治疗完全有效。使用的活性物质数量因农场和物质而异；但在处理过程中使用的溴敌隆和地芬那克诱饵多于溴敌隆诱饵。结果证实了耐药性的高发生率，并支持溴敌隆和地芬那康不应用于对抗 L120Q SNP 的建议。长期使用抗药性抗凝剂导致纯合子和抗药性传播的高流行。失败的治疗会导致长期服用抗凝剂诱饵，并使挪威大鼠活着携带，大概是高残留。使用现在允许的有效物质和引入杀鼠剂管理制度是否会减少耐药性的传播并减少野生动物中的抗凝剂残留，还有待观察。