Malaria is a mosquito-borne disease caused by the parasite Plasmodium that is responsible for over 400,000 deaths each year.
Countries have tried a variety of tactics to eliminate malaria: insecticides, anti-malarial drugs, bug netting – which have all reduced but not eliminated the disease. Many of these strategies try to disrupt the parasite’s lifecycle by exploiting Plasmodium’s dependence on hitching a ride in a mosquito to transmit to a new host.
A recent study turned the mosquito’s own immune system against the parasite. To do this they studied how Plasmodium infection affects the mosquito’s immune response. Specifically, they were looking for small pieces of RNA (called micro RNAs) that can stop other genes from being expressed.
They picked two micro RNAs that were regulated differently during infection and engineered mosquitoes to produce less of them, which resulted in a more active immune response. Both types of engineered mosquitoes were significantly more resistant to malarial infection.
If these genetically engineered mosquitoes were introduced into the wild using a gene drive, the mutation could spread through the population, making mosquitoes resistant to malaria and stopping the spread to humans.
Combining this with other malaria-resistance mutations in mosquitoes may provide a way to wipe out malaria worldwide. The idea to genetically modify mosquitoes as a way to stop malarial transmission has been proposed before. However, there is concern that genetic engineering may have adverse effects on ecosystems in ways that we can’t predict. Is it worth the risk if we have the chance to eradicate a disease?
That is a decision for bioethicists, scientists, and other informed parties to make.