Worldwide, around 580,000 people died due to malaria in 2014 alone.
To spread malarial parasite resistance among mosquito vectors, researchers fashioned a clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 nuclease (Cas9)-mediated gene drive system that can introduce and propagate an antiparasite gene among mosquitoes.
In a proof-of-concept study using Anopheles stephensimosquitoes, which account for 12% of malaria transmission in India, the authors demonstrate that an adapted gene drive can spread a dual antiparasite effector gene among mosquitoes.
The antiparasite gene, which targets two key proteins produced during an infectious stage of the human malarial parasite Plasmodium falciparum, disseminated through a highly specific gene conversion event with an efficiency greater than 99.5% in the germline of male and female mosquitoes. The genetic payload, a 17-kilobase construct, is triggered upon blood feeding by targeted mosquitoes.
The authors also uncovered a drive-dampening maternal effect on Cas9 expression that must be overcome to optimize the drive for use in the wild. Though the findings represent a promising step toward mosquito population modification, studies on the stability of effector genes in different mosquito strains and environmental conditions are required to validate the drive for malaria control.
According to the authors, with appropriate community acceptance and regulatory oversight of the gene drive in field settings, this approach might represent a powerful weapon in the growing arsenal against malaria.