First Report on Co-Occurrence Knockdown Resistance Mutations and Susceptibility to Beta-Cypermethrin in Anopheles sinensis from Jiangsu Province, China

Abstract

The increasing prevalence of insecticide resistance in Anopheles sinensis, a major vector of malaria in Jiangsu province in eastern China, threatens to compromise the successful use of insecticides in malaria control strategies. It is therefore vital to understand the insecticide resistance status of An. sinensis in the region. This study examined the nucleotide diversity of the para-sodium channel and knockdown resistance (kdr) in five field populations of adult An. sinensis mosquitoes collected in Jiangsu province, identifying the L1014F and L1014C substitutions for the first time. Competitive polymerase chain reaction (PCR) amplification of specific allele (cPASA) and polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) for resistance diagnosis were developed and validated. Comparing the results with direct sequencing revealed that the PCR-RFLP method was more sensitive and specific whereas the cPASA method was more convenient and suitable. The significant positive correlation between kdr allele frequency and bioassay-based resistance phenotype demonstrates that the frequency of L1014F and L1014C substitutions in the kdr gene provides a useful molecular marker for monitoring beta-cypermethrin resistance in natural populations of An. sinensis. Our results point to the L1014F substitution as the key mutation associated with beta-cypermethrin resistance. The high resistance and mutation frequency detected in the five populations also suggest cross-resistance with other pyrethroids may occur in An. sinensis, highlighting the need for further surveys to map insecticide resistance in China and the adoption of a rational management of insecticide application for resistance management and mosquito vector control.

Relationship between Knockdown Resistance, Metabolic Detoxification and Organismal Resistance to Pyrethroids in Anopheles sinensis

“…We did not detect any L1014S mutation as previously reported in An. sinensis populations from the Republic of Korea and Vietnam [17], [31], [47], [48]. Regarding metabolic detoxification mechanisms of resistance, GST activity was not detected as a significant variable associated with deltamethrin resistance in the multiple regression analyses.…”

Identification of a novel cytochrome P450 CYP3356A1 linked with insecticide detoxification in Bradysia odoriphaga

“…The organophosphate insecticide chlorpyrifos, with its broad insecticidal spectrum, is widely used to control underground pests and has been recommended as a main insecticide for B. odoriphaga control over the past 30 years, owing to its high soil‐absorption coefficient and low water solubility . The primary mode of action of pyrethroids is to disrupt voltage‐sensitive sodium channel function, and pyrethroids such as β‐cypermethrin are widely used in the control of many insect pests, including dipterans . Generally, applying insecticides, such as imidacloprid, thiamethoxam, chlorpyrifos and β‐cypermethrin, is the main method of pest control in Chinese chives .…”

The polymorphism and the geographical distribution of the knockdown resistance (kdr) of Anopheles sinensis in the Republic of Korea

“…sinensis complex, Anopheles sacharovi, Anopheles subpictus, Anopheles sundaicus, Anopheles aconitus, and Anopheles vagus [30-37]. A positive correlation between the kdr genotype and the resistance phenotype to pyrethroids and DDT in the Anopheles species was well documented by articles [34,38,39]. …”