Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa.
Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
PLoS One. 2019 Apr 18;14(4):e0215552. doi: 10.1371/journal.pone.0215552. eCollection 2019.
Zoophilic members of the Anopheles gambiae complex are often associated with cattle. As such, it is likely that the immature aquatic stages will be exposed to cattle faeces as a pollutant. This study aimed to examine the effect of cattle manure on members of the An. gambiae complex found in South Africa. In this study, a commercial organic fertiliser originating from cattle manure was used as a proxy for cattle faeces. Laboratory strains of An. merus, An. quadriannulatus as well as four An. arabiensis strains (SENN and MBN: insecticide susceptible, MBN-DDT: insecticide resistant, unselected, SENN-DDT: insecticide resistant: selected for resistance) were used in this study. The effect of larval fertiliser exposure on larval development rate and adult longevity was assessed in all three species. The effect of larval fertiliser exposure on subsequent adult size, insecticide tolerance and detoxification enzyme activity of the four strains of the malaria vector An. arabiensis was also assessed. Following fertiliser treatment, all strains and species showed a significantly increased rate of larval development, with insecticide susceptible strains gaining the greatest advantage. The adult longevities of An. merus, An. quadriannulatus, insecticide susceptible and resistant An. arabiensis were significantly increased following fertiliser treatment. Insecticide susceptible and resistant An. arabiensis adults were significantly larger after larval organic fertiliser exposure. Larval fertiliser exposure also increased insecticide tolerance in adult An. arabiensis, particularly in the insecticide resistant, selected strain. This 4.7 fold increase in deltamethrin tolerance translated to an increase in pyrethroid resistance intensity, which could exert operational effects. In general, larval exposure to cattle faeces significantly affects the life histories of members of the An. gambiae complex.
按蚊复合体中的嗜兽成员通常与牛有关。因此，其幼虫可能会接触到牛粪等污染物质。本研究旨在研究南非按蚊复合体成员对牛粪的反应。本研究中，使用源自牛粪的商业有机肥料作为牛粪的替代品。本研究使用了实验室饲养的淡色库蚊、三斑按蚊以及四种阿拉伯按蚊品系（SENN 和 MBN：对杀虫剂敏感，MBN-DDT：对杀虫剂具有抗性，未选择，SENN-DDT：对杀虫剂具有抗性：选择用于抗性）。在这三个物种中，评估了幼虫接触肥料对幼虫发育率和成虫寿命的影响。还评估了幼虫接触肥料对随后的成年体型、对杀虫剂的耐受性和对疟疾传播媒介阿拉伯按蚊的四种品系的解毒酶活性的影响。在施肥处理后，所有品系和物种的幼虫发育率均显著增加，对杀虫剂敏感的品系获益最大。施肥处理后，淡色库蚊、三斑按蚊、对杀虫剂敏感和抗性的阿拉伯按蚊的成虫寿命显著增加。幼虫接触有机肥料后，对杀虫剂敏感和抗性的阿拉伯按蚊成虫的体型明显增大。幼虫接触肥料还增加了成蚊对杀虫剂的耐受性，特别是在具有抗性、选择的品系中。这种对溴氰菊酯耐受性增加了 4.7 倍，转化为拟除虫菊酯抗性强度的增加，这可能会产生实际影响。总体而言，幼虫接触牛粪会显著影响按蚊复合体成员的生活史。
