Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, People's Republic of China.
Malar J. 2019 Apr 11;18(1):131. doi: 10.1186/s12936-019-2765-3.
Anopheles sinensis is the primary vector of vivax malaria in China and its control is under great threat as the development of insecticide resistance. In contrast to physiological resistance, there is no report of behavioural modifications of resistant An. sinensis after long-term insecticide use, despite their huge potential impact on malaria transmission.
Larvae or pupae of An. sinensis were collected from Yuanyang, Bishan, and Wuhe counties from southwestern to eastern China. Resistance to deltamethrin was assayed using the standard World Health Organization (WHO) susceptibility test. The frequency distribution of the kdr allele of the para-type sodium channel gene was determined by polymerase chain reaction (PCR) amplification and DNA sequencing. Contact repellency to deltamethrin-impregnated bed nets was evaluated using a modified WHO cone bioassay.
All contemporary field populations for all three geographic locations were resistant to deltamethrin, with mortality ranging from 6.00 to 26.79%. Three kdr genotypes with either an L1014F or L1014C substitution with frequencies of 76.10-100% were identified in the Bishan and Wuhe populations, but no kdr mutations were detected in the Yuanyang samples despite high phenotypic resistance. The susceptible mosquitoes exhibited significantly longer flying time and more takeoffs on deltamethrin-treated bed nets (DTN) than on untreated bed nets (UTN), suggestive of robust avoidance behaviour. However, no significant increases in the frequency of takeoffs or flying time were observed in deltamethrin-resistant An. sinensis populations when exposed on DTNs, regardless of the presence of a kdr mutation. Moreover, the first takeoff from DTNs by resistant mosquitoes significantly lagged behind compared to susceptible mosquitoes.
The An. sinensis populations were highly resistant to deltamethrin and exhibited decreased avoidance behaviour. Behavioural modification significantly associated with deltamethrin resistance, but not directly related to the presence of kdr mutations, indicating that there are additional factors contributing to the changes.
中华按蚊是中国间日疟的主要传播媒介，由于杀虫剂抗性的发展，其控制受到了巨大威胁。与生理抗性不同，尽管它们对疟疾传播有巨大的潜在影响，但在长期使用杀虫剂后，没有关于抗性中华按蚊行为改变的报道。
从中国西南到东部的原阳、璧山和涡河等县收集中华按蚊幼虫或蛹。使用标准世界卫生组织（WHO）敏感性测试来测定对溴氰菊酯的抗性。通过聚合酶链反应（PCR）扩增和 DNA 测序确定 para 型钠离子通道基因 kdr 等位基因的频率分布。使用改良的 WHO 锥形生物测定法评估对溴氰菊酯浸渍蚊帐的接触驱避性。
所有三个地理位置的当代田间种群均对溴氰菊酯产生抗性，死亡率范围为 6.00-26.79%。在璧山和涡河种群中发现了三种 kdr 基因型，均具有 L1014F 或 L1014C 取代，频率为 76.10-100%，而在原阳样本中未检测到 kdr 突变，尽管表型抗性很高。敏感蚊子在溴氰菊酯处理过的蚊帐（DTN）上的飞行时间和起飞次数明显长于未处理的蚊帐（UTN），表明存在强烈的回避行为。然而，在接触 DTN 时，无论是否存在 kdr 突变，溴氰菊酯抗性中华按蚊种群的起飞次数或飞行时间频率均未显著增加。此外，与敏感蚊子相比，抗性蚊子从 DTN 上的首次起飞明显滞后。
中华按蚊种群对溴氰菊酯高度耐药，并表现出降低的回避行为。行为改变与溴氰菊酯抗性显著相关，但与 kdr 突变的存在无关，表明还有其他因素导致了这种变化。
