For the past decade, Colorado State University researcher Ken Olson has studied the virus that causes dengue fever. The disease infects an estimated 100 million people annually, mostly in tropical regions of the world. Olson has been looking for a way to prevent the virus from infecting mosquitoes, which are the chief vectors, or carriers, of the disease.
A vaccine for dengue fever has not yet been developed. In the Proceedings of the National Academy of Sciences, Olson says he was able to genetically engineer a mosquito with a high degree of resistance to the most prevalent type of dengue fever. "We showed that it is feasible to basically turn on an innate immune pathway in the mosquito so that the mosquito is triggered to fight off the Dengue virus infection." He says what researchers are doing is killing the virus very early in the mosquito infection process, at the first step as the virus is coming in to the mosquito's gut cells.
Olson says the challenge now is to devise an ecologically safe way to move the dengue-resistant mosquito into the wild, a complicated and controversial task. He says the gene-altered mosquito may help reduce transmission of dengue fever, but it cannot be the only method for controlling the disease. "Now if you couple this as a part of an overall vector control program and vaccination program against dengue viruses, then we might have a good chance of really knocking down dengue transmission in many different parts of the world."The research is being supported by a grant from the Bill and Melinda Gates Foundation.