Tuesday, November 24, 2015

Scientists Create Malaria-Blocking Mutant Mosquitoes

known malarial transmitter, the Anopheles stephensi mosquito draws blood from a human host. Credit: CDC / Jim Gathany

Scientists at the University of California have created a strain of mutant mosquitoes capable of rapidly introducing malaria-blocking genes into a mosquito population through its offspring.

Researchers at the Irvine and San Diego campuses inserted a DNA element into the germ line of Anopheles stephensi mosquitoes which resulted in the gene preventing malaria transmission being passed on to  99.5%of offspring. A. stephensi is a leading malaria vector in Asia.

Scientists used the CRISPR method to create the mutant mosquitoes, a powerful gene editing tool that allows access to a cell’s nucleus to snip DNA to either replace mutated genes or insert new ones.

“This opens up the real promise that this technique can be adapted for eliminating malaria,” said Anthony James, Distinguished Professor of molecular biology & biochemistry and microbiology and molecular genetics at UC Irvine.

To ensure that the element carrying the malaria-blocking antibodies had reached the desired DNA site, the researchers included a protein that gave the progeny red fluorescence in the eyes. Almost 100 percent of offspring (99.5%) exhibited this trait, which James said is an amazing result for such a system that can change inheritable traits.

He added that further testing will be needed to confirm the efficacy of the antibodies and that this could eventually lead to field studies. “This is a significant first step,” said James. “We know the gene works. The mosquitoes we created are not the final brand, but we know this technology allows us to efficiently create large populations.”

Malaria is one of the world’s leading health problems. More than 40% of the world’s population live in areas where there is a risk of contracting the disease. According to the Centers for Disease Control and Prevention, 300 million to 500 million cases of malaria occur each year, and nearly 1 million people die of the disease annually – largely infants, young children and pregnant women, mostly in Africa.