Using Genetically Engineered Mosquitoes to Battle Malaria

Malaria is a well-known disease that plagues much of the world. Over the years, various techniques including the use of mosquito nets and pesticides have been implemented in an effort to combat the disease.

One scheme that has been thought up to prevent the spread of malaria is to make mosquitoes themselves resistant to the malaria pathogen as a more indirect way to prevent the transmission of the pathogen from mosquito to human. Several labs across the world including some in the United States and Europe have been testing this idea by working with transgenic mosquitoes that have been genetically manipulated to be immune to malaria.

While transgenic mosquitoes are a step in the right direction, there have been road bumps in their usage in the fight against malaria. It has been found that lab-created malaria-resistant mosquitoes are not as “fit” as their wild-type relatives and therefore are outcompeted in the natural world. This is in addition to the fact that the wild type mosquito population is so dense that it would be very difficult for a lab-synthesized gene to fully assimilate into the general mosquito population.

A team of scientists led by Bruce Hay and Chun-Hong Chen at the California Institute of Technology has been working to address this issue through the use of the model organism Drosophila melanogaster. The team devised a technique in which they produced a “selfish gene” named Medea that silences a gene needed for normal embryonic development. Female mosquitoes that carry Medea express a toxin that passes on to their oocytes. Embryos that do not inherit Medea die from the toxin. Embryos that inherit Medea live due to the expression of an antidote during embryogenesis that counteracts the toxin.

These scientists are working to transfer this work to mosquitoes. The idea is to link a Medea-type gene to a malaria resistant gene as an effective way to incorporate a malaria resistant gene into the general mosquito population.

Although this research has been groundbreaking, there remains controversy surrounding the idea of introducing a genetically modified organism into the ecosystem as well as whether this is a cost-effective solution to eradicating malaria.

Levy, Sharon. "Mosquito Modifications: New Approaches to Controlling Malaria."BioScience. Biosciencemag.org, Nov. 2007. Web. 27 May 2011.

Lichtman, Flora. "Killing Disease with Bugs." Sciencefriday.com. 30 Mar. 2007. Web. 27 May 2011.

Links:

http://www.sciencefriday.com/newsbriefs/read/125

http://www.its.caltech.edu/~haylab/publication/comments2007/BioScience.pdf