Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK.
Malar J. 2018 Feb 15;17(1):80. doi: 10.1186/s12936-018-2203-y.
Insecticide resistance threatens effective vector control, especially for mosquitoes and malaria. To manage resistance, recommended insecticide use strategies include mixtures, sequences and rotations. New insecticides are being developed and there is an opportunity to develop use strategies that limit the evolution of further resistance in the short term. A 2013 review of modelling and empirical studies of resistance points to the advantages of mixtures. However, there is limited recent, accessible modelling work addressing the evolution of resistance under different operational strategies. There is an opportunity to improve the level of mechanistic understanding within the operational community of how insecticide resistance can be expected to evolve in response to different strategies. This paper provides a concise, accessible description of a flexible model of the evolution of insecticide resistance. The model is used to develop a mechanistic picture of the evolution of insecticide resistance and how it is likely to respond to potential insecticide use strategies. The aim is to reach an audience unlikely to read a more detailed modelling paper. The model itself, as described here, represents two independent genes coding for resistance to two insecticides. This allows the representation of the use of insecticides in isolation, sequence and mixtures.
The model is used to demonstrate the evolution of resistance under different scenarios and how this fits with intuitive reasoning about selection pressure. Using an insecticide in a mixture, relative to alone, always prompts slower evolution of resistance to that insecticide. However, when resistance to both insecticides is considered, resistance thresholds may be reached later for a sequence relative to a mixture. Increasing the ability of insecticides to kill susceptible mosquitoes (effectiveness), has the most influence on favouring a mixture over a sequence because one highly effective insecticide provides more protection to another in a mixture.
The model offers an accessible description of the process of insecticide resistance evolution and how it is likely to respond to insecticide use. A simple online user-interface allowing further exploration is also provided. These tools can contribute to an improved discussion about operational decisions in insecticide resistance management.
杀虫剂抗性威胁着有效的病媒控制，特别是针对蚊子和疟疾。为了管理抗性，推荐的杀虫剂使用策略包括混合物、序列和轮换。新的杀虫剂正在开发中，有机会制定在短期内限制进一步抗性进化的使用策略。2013 年对模型和抗性实证研究的综述指出了混合物的优势。然而，最近针对不同操作策略下抗性演变的建模工作有限，且易于获取。有机会提高操作界对杀虫剂抗性如何响应不同策略而演变的机制理解水平。本文提供了一个灵活的杀虫剂抗性演变模型的简明、易懂的描述。该模型用于开发杀虫剂抗性演变的机制图景，以及它如何可能对潜在的杀虫剂使用策略做出响应。目的是让不太可能阅读更详细的建模论文的读者能够理解。本文中描述的模型本身代表了两个独立的基因，它们编码对两种杀虫剂的抗性。这允许单独、序列和混合物使用杀虫剂的表示。
该模型用于演示不同情况下的抗性演变，以及这如何与对选择压力的直观推理相吻合。与单独使用杀虫剂相比，在混合物中使用杀虫剂总是会促使对该杀虫剂的抗性演变更慢。然而，当考虑到两种杀虫剂的抗性时，序列相对于混合物可能会更晚达到抗性阈值。增加杀虫剂杀死敏感蚊子的能力（效力）对支持混合物而不是序列的影响最大，因为混合物中的一种高效杀虫剂为另一种杀虫剂提供了更多的保护。
该模型提供了对杀虫剂抗性演变过程的易懂描述，以及它如何可能对杀虫剂使用做出响应。还提供了一个简单的在线用户界面，允许进一步探索。这些工具可以为改进关于杀虫剂抗性管理中的操作决策的讨论做出贡献。
