FEATURE ARTICLE
Genetic Strategies for Controlling Mosquito-Borne Diseases
Engineered genes that block the transmission of malaria and dengue can hitch a ride on selfish DNA and spread into wild populations
Malaria infects hundreds of millions of people each year and kills a
million of them, mostly small children. It has no vaccine, and
treatments are losing efficacy as the parasite evolves to resist
their effect. Malaria, like several other tropical diseases
including dengue fever, are spread through the bite of an infected
mosquito, and public health initiatives to combat these diseases
have focused on insecticides and netting with limited success. But
what if mosquitoes could no longer transmit the disease? In the
laboratory, scientists have succeeded in adding specific genes to
the mosquito that make it unable to transmit the parasites that
cause malaria or dengue. It might be possible to cause similar
changes to wild mosquitoes. The tricky part would be getting the
disease-blocking genes to spread to the whole population: Thousands
of transgenic insects would have to breed with and eventually
replace the local mosquitoes. Furthermore, adding genes to an
organism generally hampers its ability to thrive, so natural
selection would seem to work against the modified insects.
Nonetheless, recent experiments suggest that genetically altered
mosquitoes could provide a realistic solution to the problem of
mosquito-borne diseases-provided that some of the large technical
hurdles can be overcome. Gould, Magori and Huang describe some of
the sophisticated genetic strategies that could be used to drive
anti-parasite genes into a population of wild mosquitoes as well as
the risks attendant in such a scheme.
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