Mosquitos Genetically Modified to Prevent Malaria Spread

A genetic modifications that make mosquitos incapable of spreading malaria is reported in Science Advances this week, marking another step toward the use of gene drives to eliminate the parasitic disease. In the study, scientists from Imperial College London augmented a midgut gene of the malaria mosquito Anopheles gambiae to secrete two exogenous antimicrobial peptides — called magainin 2 and melittin — that hinder oocyst development in the malaria parasites Plasmodium falciparum and Plasmodium berghei. The modification, which is capable of efficient nonautonomous gene drive, markedly delays the emergence of infectious sporozoites while simultaneously reduces the life span of homozygous female transgenic mosquitoes, the researchers write. Modeling, meantime, indicates that propagation of the genetic modification via gene drives could break the malaria transmission cycle across different epidemiological scenarios "even if the effector itself is eventually replaced by resistant alleles because of the fitness cost that it imposes," the authors note. "This modification is already designed for gene drive and requires no further adjustment before deployment, while, at the same time, it is inert on its own and thus can be safely tested in an endemic setting under standard containment protocols."