Building better mosquitoes
Mosquitoes are responsible for epidemics of dengue fever and malaria which strike at least 100 million people worldwide annually. Malaria alone kills at least one million people every year. Many research teams have tried to discover effective and affordable malaria vaccines. Now, the News and Observer writes that a project funded by the Bill & Melinda Gates Foundation wants to develop methods to control mosquitoes that transmit malaria and dengue. In fact, scientists are engineering mosquitoes, mutants which will not carry the disease. As there are many opponents to genetically modified organisms (GMOs) around the world, I wonder if such a project, which would be the first one to spread "an altered organism on wings" in the wild can be successful.
Let's start with the introduction of the very well-documented article written by Catherine Clabby.
Without mosquitoes, epidemics of dengue fever and malaria could not plague this planet. The skin-piercing insects infect one person after another while dining on a favorite meal: human blood. Eliminating the pests appears impossible. But scientists are attempting to re-engineer them so they cannot carry disease. If they manage that, they must create enough mutants to mate with wild insects and one day to outnumber them.
Researchers chasing this dream, including an N.C. State University entomologist, know they may court controversy. Genetically modified crop plants such as soybeans, corn and cotton have become common in the United States, but an altered organism on wings would be a first.
Fred Gould, Professor of Agriculture at North Carolina State University, is working with other members of his lab with the help of money provided by the Bill & Melinda Gates Foundation. He currently focuses his efforts on dengue.
Dengue is a good starting point because it is transmitted almost exclusively by a single mosquito species -- the smallish, striped-legged Aedes aegypti -- while the malaria parasite is carried by several. Focusing the effort on just one bug simplifies the science. "If you can do this with dengue, you can envision doing it with malaria," Gould said.
Below is a picture of a Aedes aegypti mosquito biting a human. (Credit: USDA, via Wikipedia)
The researchers have now successfully built mosquitoes which are unable to propagate dengue. Of course, this doesn't mean that dengue will disappear anytime soon. There are many issues to solve, both political and technical.
Scientists must convince the government and people of any country they approach that mutant bugs will fight disease without risk to people or the environment, said Sujatha Byravan, president of the Council for Responsible Genetics. "On the face of it, it sounds like it would be great. But what would the real effect be?" Byravan said.
It's also important to build an efficient strategy to release such bio-engineered insects. And the scientists are ready for experiments -- but in a 'controlled' environment.
Plans call for experiments in insect-safe cages surrounding mock homes to be built in sparsely populated land in southern Mexico within two years. "A lot of this will depend on how we conduct ourselves there. We must be open and explain what it is we want to do," said Tom Scott, a University of California San Diego biologist.
Will these altered mosquitoes fly around the world anytime soon? I really don't know. This looks at the same time like a very good and a very bad idea. Drop me a note to tell me what you think.
Sources: Catherine Clabby, The News and Observer, Raleigh, N.C., December 12, 2006; and various websites
You'll find related stories by following the links below.