CRISPR-based genetic technique eradicates malaria mosquitoes with over 99% efficiency

Good news!

Why don't we try to completely eradicate bloodsuckers? What are bloodsuckers good for?

From the significance and abstract:

"Significance

Controlling the primary African malaria vector, Anopheles gambiae mosquitoes, is crucial for reducing malaria transmission. Conventional methods relying on insecticides are losing effectiveness. The sterile insect technique (SIT) has successfully eradicated pests, but implementing it for A. gambiae is hindered by technological gaps. Our precision-guided SIT (pgSIT) uses CRISPR to induce male sterilization and female elimination for use in SIT. Through engineered Cas9 and gRNA strains, we achieve over 99.5% male sterility and over 99.9% female lethality. Genetically sterilized males display longevity, induce population suppression, and, according to models, can eliminate wild A. gambiae populations. This finding enhances the malaria genetic biocontrol toolkit, allowing scalable, confined suppression in the species.

Abstract

Controlling the principal African malaria vector, the mosquito Anopheles gambiae, is considered essential to curtail malaria transmission. However, existing vector control technologies rely on insecticides, which are becoming increasingly ineffective. Sterile insect technique (SIT) is a powerful suppression approach that has successfully eradicated a number of insect pests, yet the A. gambiae toolkit lacks the requisite technologies for its implementation. SIT relies on iterative mass releases of nonbiting, nondriving, sterile males which seek out and mate with monandrous wild females. Once mated, females are permanently sterilized due to mating-induced refractoriness, which results in population suppression of the subsequent generation. However, sterilization by traditional methods renders males unfit, making the creation of precise genetic sterilization methods imperative. Here, we introduce a vector control technology termed precision-guided sterile insect technique (pgSIT), in A. gambiae for inducible, programmed male sterilization and female elimination for wide-scale use in SIT campaigns. Using a binary CRISPR strategy, we cross separate engineered Cas9 and gRNA strains to disrupt male-fertility and female-essential genes, yielding >99.5% male sterility and >99.9% female lethality in hybrid progeny. We demonstrate that these genetically sterilized males have good longevity, are able to induce sustained population suppression in cage trials, and are predicted to eliminate wild A. gambiae populations using mathematical models, making them ideal candidates for release. This work provides a valuable addition to the malaria genetic biocontrol toolkit, enabling scalable SIT-like confinable, species-specific, and safe suppression in the species."

CRISPR-based genetic technique eradicates malaria mosquitoes with over 99% efficiency Scientists at the University of California, USA, have developed a precision-guided sterile insect technique to eliminate the primary African malaria vector, Anopheles gambiae mosquitoes, and subsequently reduce malaria transmission.

Eliminating malaria vectors with precision-guided sterile males (open access)

Credits: Johns Hopkins Bloomberg School of Public Health: Global Health NOW

Fig. 1 Homozygous pgSIT gRNA females crossed to Cas9 males produce nearly exclusively sterile male F1 offspring.