Monitoring of Permethrin Resistance in Houseflies around the Experimental Animal Center

This study was conducted from 2023 to 2025 to assess the resistance of houseflies (Musca domestica), which is a significant disease vector, to permethrin in diverse environments surrounding the Experimental Animal Center of Chiang Mai University. These environments included forests, farmlands, markets, indoor areas, and villages. Houseflies were collected using bait and netting methods, then classified and subjected to toxicity tests using a topical application technique to determine resistance levels. The findings indicate that, although housefly populations in this region have developed permethrin resistance over approximately two decades, the environmental diversity has helped slow this progression compared to other areas. Given the importance of maintaining controlled environments, especially in barrier laboratories, pyrethroid insecticides like permethrin are commonly used due to their safety and environmental compatibility. However, prolonged and exclusive use increases the risk of resistance development. As permethrin is widely used across different sectors, the threat of resistance is becoming increasingly critical. To mitigate this issue, the study recommends maintaining ecological diversity around the center and implementing targeted resistance management strategies based on bioassay data to ensure effective vector control.