New malaria fighting technique announced

Scientists from the University of Arizona have successfully developed a mosquito that is immune to the parasite Plasmodium, the cause of malaria, and hope to one day replace wild mosquitoes with their lab-bred population.

The study, funded by the National Institute of Health, will appear in the July issue of the journal Public Library of Science Pathogens. Of the estimated 250 million people that are infected with malaria each year, 1 million, mostly children, die. Ninety-percent of cases are in Sub-Saharan Africa.

"If you want to effectively stop the spreading of the malaria parasite, you need mosquitoes that are no less than 100 percent resistant to it. If a single parasite slips through and infects a human, the whole approach will be doomed to fail," Michael Riehle, head of the effort and an entomology professor at the University of Arizona’s College of Agriculture and Life Sciences, said.

"We were surprised how well this works," Riehle added. "We were just hoping to see some effect on the mosquitoes' growth rate, lifespan or their susceptibility to the parasite, but it was great to see that our construct blocked the infection process completely."

To engineer the malaria-proof mosquito, Rheile and his team designed a piece of genetic information that could be inserted into a mosquito’s genetic sequence. The code acts as a molecular switch that controls a portion of the mosquito’s metabolic functions at the cellular level. It permanently activates an enzyme known as Akt, which is critical in running the mosquito’s immune response and helps determine its natural lifespan and growth rate.

Rheile hopes to focus on the existing mosquito population as the key to eliminating the disease.

"The eradication scenario requires three things: A gene that disrupts the development of the parasite inside the mosquito, a genetic technique to bring that gene into the mosquito genome and a mechanism that gives the modified mosquito an edge over the natural populations so they can displace them over time," Rheile said.

Currently, there are no approved vaccines for malaria. Those that have gone to clinical trials have proven to be ineffective or only effective in the short term.