Comparison of chlorpyrifos resistance in Culex pipiens pipiens (Diptera: Culicidae) collected from Northern and Southern Tunisia |
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| Authors: | Ahmed Tabbabi Raja Ben Cheikh Ali Laamari Mohamed Feriani Chokri Boubaker Ibtissem Ben Jha Hassen Ben Cheikh |
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| Institution: | 1. Laboratory of Genetics, Faculty of Medicine of Monastir, University of Monastir, Monastir, Tunisia;2. Department of Hygiene and Environmental Protection, Ministry of Public Health, Tunis, TunisiaJabeur Daaboub and Ahmed Tabbabi contributed equally to this work. |
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| Abstract: | In this study, we investigated resistance to the organophosphates chlorpyrifos in Tunisian populations of Culex pipiens pipiens. Three field populations were collected from Northern and central Tunisia between 2003 and 2005 and used for the bioassays tests. Our results registered moderate and high levels of resistance to chlorpyrifos which ranged from 33.8 to 111. The chlorpyrifos resistant populations were highly resistant to propoxur indicated an insensitive acetylcholinesterase 1 (AChE 1). The highest frequency of AChE 1 resistant phenotypes (64%) was recorded in the most resistant population (sample # 1). Bioassays conducted in the presence of synergists showed that not esterases were involved as the resistance mechanism to chlorpyrifos. However, CYP450 was partly involved in the resistance of the most resistant sample (# 1). Starch electrophoresis showed that three esterases were present in studied samples: A2‐B2, A4‐B4 and B12. Results are discussed in relation to the selection pressure caused by insecticide treatments. |
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| Keywords: | Culex pipiens pipiens chlorpyrifos resistance detoxification enzymes AChE 1 Tunisia |
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