Targeting mosquitoes to target malaria
Anopheline mosquitoes transmit the malaria parasite, but the insects themselves are prone to their own infections. Lovett et al. engineered a specific fungal pathogen of anophelines to carry insect-selective toxins. The effectiveness of this fungus for controlling mosquitoes was trialed in near-field conditions in Burkina Faso in a setup called MosquitoSphere. Approximately 75% of wild insecticide-resistant mosquitoes released into the environment became infected with the transgenic fungus, causing population collapse within 45 days.
Science, this issue p. 894
Malaria control efforts require implementation of new technologies that manage insecticide resistance. Metarhizium pingshaense provides an effective, mosquito-specific delivery system for potent insect-selective toxins. A semifield trial in a MosquitoSphere (a contained, near-natural environment) in Soumousso, a region of Burkina Faso where malaria is endemic, confirmed that the expression of an insect-specific toxin (Hybrid) increased fungal lethality and the likelihood that insecticide-resistant mosquitoes would be eliminated from a site. Also, as Hybrid-expressing M. pingshaense is effective at very low spore doses, its efficacy lasted longer than that of the unmodified Metarhizium. Deployment of transgenic Metarhizium against mosquitoes could (subject to appropriate registration) be rapid, with products that could synergistically integrate with existing chemical control strategies to avert insecticide resistance.