18: Chemosensory proteins and sub-lethal insecticide exposure: The complexity of insecticide resistance in Anopheles mosquitoes

Monday, November 16, 2020

4:25 PM - 4:40 PM EST

Presenting Author(s)

Victoria Anne Ingham

Liverpool School of Tropical Medicine
Liverpool, United Kingdom

Co-Author(s)

AA

Amalia Anthousi

Liverpool School Of Tropical Medicine
Liverpool, England, United Kingdom
VD

Vassilis Douris

Institute of Molecular Biology and Biotechnology
Heraklion, Iraklion, Greece
NH

Nicholas J Harding

University Of Oxford
oxford, England, United Kingdom
GL

Gareth Lycett

Liverpool School Of Tropical Medicine
Liverpool, England, United Kingdom
MM

Marion Morris

Liverpool School Of Tropical Medicine
Liverpool, England, United Kingdom
JV

John Vontas

Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas
Iraklion, Iraklion, Greece
HR

Hilary Ranson

hilary.ranson@lstmed.ac.uk
Liverpool, England, United Kingdom

Malaria control programs are heavily reliant on the use of insecticides which target and kill the adult mosquitoes before they can pass on the malaria parasite. Key amongst these control measures are insecticide treated bed nets which accounted for ~70% of the reduction in malaria cases between 2000 and 2015. All bed nets currently distributed are impregnated with pyrethroid insecticides, resistance to which are widespread. Worryingly, the world malaria report issued by WHO has shown a plateauing of cases over the last two years, closely mirroring the spread of insecticide resistance.

Until recently, insecticide resistance has been attributed to four main resistance mechanisms, including target site mutations, increased activity of detoxification enzymes, thickening of the adult cuticle and behavioural changes. However, through mining transcriptomic data we discovered a protein, SAP2, is critical for pyrethroid resistance in West Africa. SAP2 is a member of the chemosensory protein family (CSPs), and is highly enriched in the legs, the main point of contact with bed nets. The involvement of CSPs in resistance has been hinted at in agricultural pests and so these findings likely apply to resistance in a wider context. Interestingly, SAP2 is strongly induced by pyrethroid exposure, indicating sub-lethal insecticide exposure induces key changes in underlying gene expression. In this talk, I will highlight potential new insecticide resistance mechanisms in Anopheles mosquitoes with a particular focus on chemosensory proteins.