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Published on: August 23, 2018
Metabolic Resistance in Permethrin-Resistant Florida Aedes aegypti (Diptera: Culicidae)
Sierra M Schluep1, Eva A Buckner1
1Florida Medical Entomology Laboratory, Department of Entomology and Nematology, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, FL 32962, USA.
Abstract:
Aedes aegypti is the principal mosquito vector for many arthropod-borne viruses (arboviruses) including dengue, chikungunya, and Zika. In the United States, excessive permethrin use has led to a high frequency of resistance in mosquitoes. Insecticide resistance is a significant obstacle in the struggle against vector-borne diseases. To help overcome metabolic resistance, synergists that inhibit specific metabolic enzymes can be added to formulated pyrethroid products. Using modified CDC bottle bioassays, we assessed the effect of three inhibitors (piperonyl butoxide (PBO), which inhibits oxidase activity; S.S.S-tributyl phosphorotrithioate (DEF), which inhibits esterase activity; and diethyl maleate (DM), which inhibits glutathione transferase activity) + permethrin. We performed these against 20 Florida Ae. aegypti populations, all of which were resistant to permethrin. Our data indicated that 11 out of 20 populations (55%) exhibited metabolic resistance. Results revealed 73% of these populations had significant increases in mortality attributed to DEF + permethrin, 64% to PBO + permethrin, and 55% to DM + permethrin compared to permethrin alone. Currently, PBO is the only metabolic enzyme inhibitor added to formulated pyrethroid products used for adult mosquito control. Our results suggest that the DEF and DM inhibitors could also be useful additives in permethrin products, especially against metabolically resistant Ae. aegypti mosquitoes. Moreover, metabolic assays should be conducted to better inform mosquito control programs for designing and implementing integrated vector management strategies.
Insights
Insecticide resistance in Aedes aegypti mosquitoes is a major challenge. New synergists, DEF and DM, show promise in increasing permethrin effectiveness against resistant mosquito populations.
Area of Science:
- Medical Entomology
- Insecticide Resistance
- Public Health
Background:
- Aedes aegypti mosquitoes transmit arboviruses like dengue and Zika.
- Widespread permethrin use has led to significant insecticide resistance in Aedes aegypti populations.
- Insecticide resistance poses a major obstacle to controlling vector-borne diseases.
Purpose of the Study:
- To evaluate the efficacy of three metabolic enzyme inhibitors (PBO, DEF, DM) when combined with permethrin against resistant Aedes aegypti populations.
- To identify potential synergists that can enhance the effectiveness of pyrethroid insecticides for mosquito control.
Main Methods:
- Modified CDC bottle bioassays were used to test permethrin in combination with piperonyl butoxide (PBO), S.S.S-tributyl phosphorotrithioate (DEF), and diethyl maleate (DM).
- Assays were conducted on 20 permethrin-resistant Aedes aegypti populations from Florida.
- Metabolic resistance was identified in 55% of the tested populations.
Main Results:
- Combinations of permethrin with DEF, PBO, and DM significantly increased mosquito mortality compared to permethrin alone.
- DEF + permethrin resulted in increased mortality in 73% of populations, PBO + permethrin in 64%, and DM + permethrin in 55%.
- These findings highlight the potential of DEF and DM as effective synergists.
Conclusions:
- DEF and DM inhibitors show potential as additives to permethrin products to combat metabolic resistance in Aedes aegypti.
- Incorporating these synergists could improve the efficacy of current mosquito control strategies.
- Further metabolic assays are recommended to inform integrated vector management programs.
