14. Genetic control of vectors

Abstract

In a context of tighter regulations on approved insecticide molecules, the spread of insecticide resistance in insect vectors of human and animal diseases and the introduction of exotic vectors to new territories call for the development of new pest control methods and strategies. New genetic control methods, related to the ancestral sterile insect technique (SIT), show particular promise and are being developed in response to increasing health and agricultural challenges. These include the use of symbionts like Wolbachia and the use of transgenic insect strains, some of which incorporate gene editing techniques that can lead to transgene spread (gene drive). Here we present the principles, associated opportunities and risks, as well as the degree of advancement of these various techniques for a subset of livestock pests and disease vectors including screwworms, tsetse, mosquitoes and stomoxes. We then present some case studies on recent improvements in the use of the SIT in tsetse and the release of insects carrying a dominant lethal gene, symbiontbased approaches and gene drive in mosquitoes. Finally, we call to speed up the development of genetic control, within a rigorous benefit-risk analysis framework including international public consultation.

Reduction in Egg Fertility of Aedes albopictus Mosquitoes in Greece Following Releases of Imported Sterile Males

“…The current management plan includes coordinated actions such as monitoring protocols and activities for stakeholders and local communities. The implementation of new control approaches, such as the sterile insect technique (SIT), Wolbachia-based strategies, pyriproxyfen autodissemination and transgenic technologies have recently been proposed [ 6 , 13 ]. SIT is a method of insect control with a strong record of successful applications against a range of agricultural insect pests [ 14 , 15 ].…”

Challenges of Robust RNAi-Mediated Gene Silencing in Aedes Mosquitoes

“…A different approach targets genes involved in sex determination [19][20][21][22] or male or female fertility [23][24][25] to reduce the population size of the next generation by producing a sex bias, thereby reducing the availability of mating partners or the number of offspring per individual, respectively. An RNAi-based sexing approach could also be used for genetic control methods based on the release of males [26], as there is currently no perfect genetic sexing strain available [27], and most of the programs upscaling mosquito genetic control are based on automated sorters using the phenotypical differences between pupae [28,29] or adults [30].…”