Scientists have developed a breed of mosquitoes that is resistant to malaria.
By altering the DNA of Anopheles stephensi mosquitoes, scientists at the University of California produced an immune response in the insect that combated the malaria parasite in adulthood and rendered the mosquito unable to transmit the pathogen to humans via their bite.
Researchers injected mosquito eggs with a modified gene that caused the insect's immune system to produce antibodies capable of killing or stalling the development of Plasmodium falciparum, the deadliest form of malaria.
The injected gene does not affect the mosquito's ability to live or reproduce. And according to researchers, it’s dominant, meaning that the GM mosquito would not only be able to survive in the wild but also thrive.
"This is the first model of a malaria vector with a genetic modification that can potentially exist in wild populations and be transferred through generations without affecting their fitness," Anthony James, lead author on the study, told Wired magazine.
The new report was published online in Proceedings of the National Academy of Sciences June 11. The research was carried out by researchers at the University of California-Irvine (UCI) and the Pasteur Institute in Paris, France.
The genetic modification model could be used to effectively combat malaria, as well as other diseases transmitted to humans by mosquitoes, such as dengue fever or West Nile, James said.
Malaria depends on Anopheles mosquitoes, one of 30-40 mosquito species that transmit the parasite, for part of its life cycle. By eliminating the pathogen inside its insect host, communities could effectively prevent the spread of malaria — a disease that killed more than 650,000 people in 2010, most of whom were children.
In order for this to become a reality, however, millions of mosquitoes must first be bred in the laboratory before being released into the environment at key intervals.
This no easy feat, James explained, as caring for tropical insects is a very labor-intensive process.
"We have to figure out how these things are going to scale up," he said. "This is not something that people are going to be doing in their garage."
According to James, it will take at least another year to be ready for field trials, and potentially more time will be needed to address social, legal and ethical concerns of releasing GM mosquitoes into malaria-endemic environments.
If successful, this would not be the first time GM mosquitoes would be released in mass. GM mosquitoes able to mate but unable to reproduce are already being released in some regions for the purpose of mosquito population control.
The UCI study comes on the heels of similar research by the Johns Hopkins Malaria Research Institute published late last year. The Hopkins study differed in that it genetically reworked the immune system to produce more of an innate protein, Re12, when feeding in order to induce attacks on the malaria parasite using anti-parasitic molecules.
For more information on GM mosquitoes, check out this slideshow done by Wired magazine.
