Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, 1 Modderfontein Road, Sandringham, Johannesburg, 2192, South Africa.
Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2193, South Africa.
Sci Rep. 2022 Mar 9;12(1):3877. doi: 10.1038/s41598-022-07798-w.
Insecticide-based vector control is key to the reduction and elimination of malaria. Although insecticide resistance is common in malaria vector populations, the operational implications are often unclear. High intensity pyrethroid resistance in the major malaria vector Anopheles funestus has been linked to control failure in Southern Africa. The aim of this study was to assess linkages between mosquito age, blood feeding and the intensity of pyrethroid resistance in two An. funestus laboratory strains that originate from southern Mozambique, namely the moderately pyrethroid resistant FUMOZ and the highly resistant FUMOZ-R. Resistance tended to decline with age. This effect was significantly mitigated by blood feeding and was most apparent in cohorts that received multiple blood meals. In the absence of insecticide exposure, blood feeding tended to increase longevity of An. funestus females and, following insecticide exposure, enhanced their levels of deltamethrin resistance, even in older age groups. These effects were more marked in FUMOZ-R compared to FUMOZ. In terms of programmatic decision-making, these data suggest that it would be useful to assess the level and intensity of resistance in older female cohorts wherever possible, notwithstanding the standard protocols for resistance testing using age-standardised samples.
基于杀虫剂的病媒控制是减少和消除疟疾的关键。尽管杀虫剂抗性在疟疾媒介种群中很常见，但其操作意义通常并不明确。在南非，主要疟疾媒介按蚊（Anopheles funestus）中的高强度拟除虫菊酯抗性与控制失败有关。本研究旨在评估来自莫桑比克南部的两个按蚊（An. funestus）实验室品系中蚊子年龄、吸血和拟除虫菊酯抗性强度之间的联系，这两个品系分别是中度拟除虫菊酯抗性的 FUMOZ 和高度抗性的 FUMOZ-R。抗性随年龄的增长而下降。这种影响通过吸血得到显著缓解，在接受多次吸血的群体中最为明显。在没有杀虫剂暴露的情况下，吸血往往会延长按蚊雌性的寿命，并且在暴露于杀虫剂后，即使在年龄较大的群体中，也会增强其对溴氰菊酯的抗性。与 FUMOZ 相比，FUMOZ-R 的这些影响更为明显。就决策制定而言，这些数据表明，无论使用年龄标准化样本的标准抗性测试方案如何，在尽可能的情况下评估老年雌性群体的抗性水平和强度都是有用的。
