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Julien Vézilier a le plaisir de vous inviter à sa soutenance de thèse qui se déroulera le Mardi 21 Juin, à 9H30, à l'amphithéâtre du bâtiment des plantes, à l'IRD de Montpellier.

 

Titre: Résistance aux insecticides et transmission de la malaria chez le moustique Culex pipiens

Title: Insecticide resistance and malaria transmission by Culex pipiens mosquitoes


Abstract:

 

The evolution of insecticide resistance in mosquitoes threatens our ability to control many-vector-transmitted diseases, thereby raising serious public health issues. Insecticide resistance entails numerous physiological changes in mosquitoes. This thesis investigates whether these physiological changes alter the quality of mosquitoes as vectors of malaria. To address this issue, we developed a new experimental system consisting in the avian malaria parasite Plasmodium relictum SGS1 and its natural vector, the mosquito Culex pipiens. I investigated the impact of two insecticide resistance mechanisms (target site resistance and metabolic resistance) on several mosquito and parasite life history traits relevant for malaria transmission. The effect of different insecticide resistant genes was evaluated using both isogenic laboratory mosquito strains (i.e. against a homogeneous genetic background) and sympatric field caught mosquitoes (i.e. under the more realistic, albeit noisier, conditions of a heterogeneous genetic background). This work showed that insecticide resistance has a pleiotropic effect on several mosquito traits (immunocompetence, longevity, fecundity), whereas it has only a limited effect on Plasmodium development. I will discuss, on the one hand, the need to pursue such a multi-factorial approach (combining the mosquito physiology, immunity and behavior) to better understand the impact of insecticide resistance on malaria transmission and, on the other hand, the promising perspectives offered by this new experimental system for studying the evolutionary-ecology of infectious diseases.