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ORIGINAL RESEARCH article
Front. Cell. Infect. Microbiol.
Sec. Veterinary and Zoonotic Infection
Volume 15 - 2025 |
doi: 10.3389/fcimb.2025.1496849
Distribution and frequency of genetic mutations in three insecticide targets in field populations of Culex tritaeniorhynchus in Mianyang City, Sichuan Province, China
Provisionally accepted- Mianyang City Center for Disease Control and Prevention, Mianyang, China
Japanese encephalitis (JE) is an important mosquito borne infectious disease which is mainly transmitted by Culex tritaeniorhynchus Giles (1901) in China. At present, vector control remains an important means to prevent and control vector-borne diseases including JE. The development of insecticide resistance has seriously threatened the effectiveness of insecticide-based vector control programmes.Therefore, understanding insecticide resistance in the targe pest is essential to inform evidence-based vector control. In Mianyang City of Sichuan Province of China, Cx. tritaeniorhynchus is the dominant mosquito species, and JE has been documented in this city. Unfortunately, there is little information on the status and underlying mechanisms of insecticide resistance in field populations of Cx. tritaeniorhynchus, the main JE vector in this region. In the study, a total of 314 adults of Cx. tritaeniorhynchus, collected from 6 sites across Mianyang City, were inspected for resistance-conferring mutations in three genes encoding voltage-gated sodium channel (VGSC), Gamma-aminobutyric acid (GABA) receptor Rdl subunit (Rdl), and acetylcholinesterase (AChE) by DNA Sanger sequencing. The results showed that the classical L1014F mutation in VGSC was distributed in all the 6 populations at varying frequencies from 16.98% to 27.78%, and the frequency of F455W mutation in AChE was extremely high (97.06%-100%). Notably, the conserved mutations A296S and V327I previously reported in the Rdl of some other species of mosquitoes were discovered in Cx. tritaeniorhynchus for the first time. The frequency of the resistant Rdl 296S allele was 62.04% to 94.00%, while the V327I mutation was present at a 3 much lower frequency ranging from 0.93% to 1.8%. Overall, the prevelant co-existence of resistance-conferring mutations in multiple insecticide target proteins in Cx. tritaeniorhynchus populations in Mianyang City indicates a worrying status of insecticide resistance, and suggests that it is highly required to monitor the phenotypic resistance of Cx. tritaeniorhynchus on a regular basis.
Keywords: Insecticide Resistance, Culex tritaeniorhynchus, voltage-gated sodium channel, GABA receptor Rdl subunit, Acetylcholinesterase, Rdl A296S mutation
Received: 15 Sep 2024; Accepted: 13 Jan 2025.
Copyright: © 2025 Xie, Tang, Sun, Huang, Dong and Wen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Meilin Tang, Mianyang City Center for Disease Control and Prevention, Mianyang, China
Hongying Sun, Mianyang City Center for Disease Control and Prevention, Mianyang, China
Zhengzheng Huang, Mianyang City Center for Disease Control and Prevention, Mianyang, China
Mengmeng Dong, Mianyang City Center for Disease Control and Prevention, Mianyang, China
Xianying Wen, Mianyang City Center for Disease Control and Prevention, Mianyang, China
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