Tuesday, June 26, 2012

GE Mosquitoes May Assist Malaria Control

Malaria-Resistant Mosquitoes Bred in Lab for First Time

Releasing such mosquitoes in strategic locations could dramatically reduce the spread of malaria.  Scientists may have developed a new tool for combating malaria, according to a recent study in the Proceedings of the National Academy of Sciences.

After more than 20 years of genetic experimentation, researchers have discovered how to breed malaria-resistant mosquitoes that are unable to infect humans with their bites.

"We see a complete deletion of the infectious version of the malaria parasite," said Anthony James, a microbiology and molecular genetics professor at the University of California, Irvine, and the lead author of the report. This can help to "significantly reduce human sickness and death," he added.

With the help of fellow researchers from the Pasteur Institute in Paris, James and his colleagues were able to alter the DNA of Anopheles stephensi mosquitoes, which are major transmitters of the most deadly strain of malaria -- Plasmodium falciparum.

By microinjecting a specially engineered gene into the mosquitoes' eggs, the scientists produced insects that were unable to transmit the disease when they reached adulthood. More importantly, the gene that James' team created was dominant. In other words, introducing it into a wild population of mosquitoes would achieve the same result as placing a group of brown-eyed humans into a blue-eyed population: gradually, fewer children would be born with the recessive, blue-eyed gene.

This means that releasing the mosquitoes in strategic locations could dramatically reduce the spread of malaria, James said.

According to the World Health Organization, more than 650,000 people died from malaria in 2010, most of whom were African children. Some researchers believe this number could climb even higher due to climate change, which is expected to increase rainfall in many regions. More puddles and swampland would provide additional breeding grounds for mosquitoes -- translating into more cases of malaria (ClimateWire, Nov. 21, 2011).

People who have never been exposed to the disease also run the highest risk of infection, so mosquitoes may spread malaria to countless new victims as they follow the rains into fresh territories, say experts.

To make James' malaria-fighting research a reality, millions of mosquitoes would need to be bred in a lab and released into the wild at key intervals.  "We have to figure out how these things are going to scale up," explained James, who says the process of caring for tropical mosquitoes can be very labor-intensive. "This is not something that people are going to be doing in their garage."

Aside from malaria, he believes, the research could ultimately be tailored to prevent other mosquito-borne diseases, such as the West Nile virus and dengue fever.

"I'm pretty enthusiastic that in five years, we'll have tools we'll be able to use," although the ethical, social and legal aspects will likely slow progress, he said.

By Lacey Johnson and ClimateWire June 18, 2012
Reprinted from Scientific American on line ; See for original article  http://www.eenews.net/.
This is a potential game changer for the fight against malaria, if larger scale operations to produce GE mosquitoes that do not have have the disease in the mosquitoes, can be developed at modest cost.  Scaling up while controlling costs and enhancing effectiveness, will be a big task. 
Malaria transmission is a complex route, and the use of treated bed nets has made a big impact where they are used.  Many more now getting around due to greater support from donors.
But to have mosquitoes that do not carry the disease would, I think be a real breakthrough.  Yes, there are some questions about ethics over GE mosquitoes, but with millions affected each year aound the world, breaking the cycle of infection using saymass release of GE mosquitoes could be very important for many regions.
And with dengue also a major world wide problem, particularly in Asia, there are other spin offs if the technology works effectively.


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