Anopheles stephensi, a vector of malaria.
Mosquitoes that carry malaria can be genetically modified to prevent them from transmitting the disease, at least to mice, according to new research.
The finding — published in the 23 May issue of Nature — suggests that genetic manipulation of malaria vectors could become an important tool for halting the transmission of malaria, which kills one to three million people every year.
Junitsu Ito from the Case Western Reserve University in Cleveland, Ohio, and colleagues inserted a gene into mosquitoes that makes a molecule known to block malaria parasite development.
The molecule prevents Plasmodium, the malaria parasite, from moving from the mosquito's gut to its salivary glands. This migration is crucial, as it underpins the transmission of malaria from the blood of one person into another by a mosquito's bite. Inserted into the germ line, the gene is passed on to the mosquito's offspring.
The researchers found that transgenic mosquitoes were at least 80 per cent less effective at spreading a mouse form of malaria.
But whether the same gene will prevent transmission of human malaria remains to be seen. And even if it does, a transgenic approach to malaria control is not yet feasible, the authors warn. An inserted gene must persist in the wild mosquito population, and the risks of releasing a genetically modified, and potentially harmful organism into the environment, remain to be investigated.
Reference: Nature, 23 May 2002
Link to news and views article 'Anti-malarial mosquitoes?'
Link to paper by Junitsu Ito et al
Photo credit: WHO/TDR