Transgenic Metarhizium pingshaense synergistically ameliorates pyrethroid-resistance in wild-caught, malaria-vector mosquitoes

• Published in: PloS one 2018-09, Vol.13 (9), p.e0203529
• Main Authors: Bilgo, Etienne, Lovett, Brian, Bayili, Koama, Millogo, Abel Souro, Saré, Issiaka, Dabiré, Roch K, Sanon, Antoine, St Leger, Raymond J, Diabate, Abdoulaye
• Format: Article
• Language: English
• Subjects: Animals; Anopheles - drug effects; Anopheles - microbiology; Aquatic insects; Ascomycota; Bioassays; Biological control; Biological Control Agents - pharmacology; Biological effects; Biology and Life Sciences; Biopesticides; Burkina Faso; Care and treatment; Control; Copyright; Culicidae; Drug Synergism; Environmental aspects; Female; Fluorescence; Fungi; Genetic engineering; Health aspects; Impact resistance; Infections; Insecticide resistance; Insecticide Resistance - drug effects; Insecticide-Treated Bednets; Insecticides; Insecticides - pharmacology; Laboratories; Malaria; Medicine and Health Sciences; Metarhizium; Metarhizium - genetics; Metarhizium - growth & development; Mosquito Control - methods; Mosquito Vectors - drug effects; Mosquito Vectors - microbiology; Mosquitoes; Neurotoxins; Neurotoxins - genetics; Parasites; Permethrin; Permethrin - pharmacology; Pesticide resistance; Pyrethrins - pharmacology; Pyrethroids; Tubes; Vector-borne diseases; Vectors
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0203529

Transgenic Metarhizium pingshaense expressing the spider neurotoxin Hybrid (Met-Hybrid) kill mosquitoes faster and at lower spore doses than wild-type strains. In this study, we demonstrate that this approach dovetails with the cornerstone of current malaria control: pyrethroid-insecticides, which are the cornerstone of current malaria control. We used World Health Organization (WHO) tubes, to compare the impact on insecticide resistance of Met-Hybrid with red fluorescent M. pingshaense (Met-RFP), used as a proxy for the wild-type fungus. Insecticides killed less than 20% of Anopheles coluzzii and Anopheles gambiae s.s. mosquitoes collected in a malaria endemic region of Burkina Faso where pyrethroid use is common. Seven days post-infection, mortality for insecticide-sensitive and resistant mosquitoes averaged 94% with Met-Hybrid and 64% with Met-RFP, with LT80 values of 5.32±0.199 days and 7.76±0.183 days, respectively. Eighty nine percent of insecticide-resistant mosquitoes exposed to permethrin five days post-infection with Met-Hybrid died within 24 hours: only 22% died from Met-Hybrid alone over this 24-hour period. Compared to Met-RFP, Met-Hybrid also significantly reduced flight capacity of mosquitoes 3 to 5 days post-infection. Based on WHOPES phase I laboratory susceptibility bioassays, transgenic Met-Hybrid provides effective biological control for adult African malaria vectors that may be used to synergistically manage insecticide resistance with current methods.