A team of researchers from Johns Hopkins University in Baltimore has created genetically engineered mosquitoes that are resistant to the malaria-causing parasite. Recent tests conducted by the researchers, and published in the Proceedings of the National Academy of Sciences this week, indicate that the new strain of mosquitoes is hardier than its malaria-carrying brethren, suggesting that they could outlive and eventually replace the disease-bearing variety of mosquito if introduced in the wild.
One of the authors of the study, Assistant Professor of Microbiology and Immunology Jason Rasgon from Johns Hopkins School of Public Health, assured the BBC in an interview that the project is still in its early stages. It could be a decade before the project culminates in the release of genetically altered mosquitoes into the environment, he said.
Rasgon and his associates have demonstrated that their "transgenic malaria-resistant mosquitoes" have a fitness advantage over other mosquitoes when feeding on blood infected with plasmodium parasites. In ordinary mosquitoes, the parasites live in the insect's gut and are passed on in the saliva of an infected insect each time it "bites," or takes a new blood meal. The transgenic mosquitoes carry a gene that makes them resistant to the malaria parasite, and new tests show that they can outlive natural disease-bearing mosquitoes, as well. Along with the plasmodium resistance gene, the researchers also inserted a gene to give the mosquitoes fluorescent green eyes, making it easier to distinguish them from the ordinary strain.
Rasgan acknowledges that while the research is promising, difficult questions still need to be answered, including addressing important "social, ethical and legal issues associated with releasing transgenic organisms into the environment."
An estimated 300 million people worldwide contract malaria each year, resulting in up 1.5 million deaths. Efforts to control malaria mosquitoes have reduced the geographic areas where the disease in rampant. Malaria outbreaks are now largely confined to Africa, Asia and Latin America.