Scientists Engineer Mosquitoes That Can't Cause Malaria Infection


SCIENTISTS are genetically engineering mosquitoes in an attempt to wipe out malaria, the disease responsible for more deaths worldwide than any other.

Anthony James, a professor of microbiology and molecular genetics at the University of California, whose lab is working on mosquitoes that cannot host the malaria parasite, said some strains are now ready to be tested outside the lab.

Speaking at the Biotech Bugs conference in Washington DC, sponsored by the Pew Initiative on Food and Biotechnology, Prof James said his team has been working on "introgressing" genes for malaria resistance into existing populations of mosquitoes. The theory of the work is that such genes introduced at high enough frequencies will decrease transmission and result in less disease and death from malaria, possibly even bringing an end to it.

The research is timely as the emerging insecticide resistance of mosquitoes is crippling some of the once-effective approaches used to control them, such as spraying.

Malaria is caused by any one of four species of one-celled parasites called plasmodium. The parasite is spread to people by the female anopheles mosquito. The World Health Organisation estimates that about 1.3 million people die from the disease annually.

Prof James said public concern about the release of genetically modified organisms into the wider environment needed to be addressed before his work could be taken into the field.

He said: "I think we have reached quite a critical point in the development and use of these organisms. We need to identify the next level in this whole adventure. What we need to do is develop a catalogue of what the concerns are. Scientists are going to have different lists from people who do legal work, people who are ministers of health, people who are looking for votes."

But scientists have a history of getting it wrong, even as they try to save the world from insect-borne scourges, said entomologist Fred Gould of North Carolina State University. "In the late 1940s entomologists had no reason to doubt that DDT would cure the world's pest problems," he told the conference.

DDT, it turned out, affected a range of animals and drove some bird species to near-extinction by weakening their eggshells.

"In the 1960s, advocates of biological control did not consider that imported predators of insect pest species might cause extinction of rare species," Mr Gould added.