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July 15, 2010
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An estimated one million people die each year from malaria, a parasitic infection transmitted by mosquitoes. Current control strategies involve blasting the bugs with insecticides, or using drugs to kill the parasite once it infects humans. Unfortunately, these methods are becoming less effective as both pests evolve ways to resist the toxic treatments, so new methods to prevent malaria are sorely needed.
For malaria to spread, a female Anopheles mosquito must first ingest the parasite by dining on an infected person. Once inside the mosquito, the parasite undergoes an approximately two-week maturation process, traveling from the mosquito gut to the salivary gland where it is then ready to be spread to other human hosts.
Fortunately for humans, mosquitoes in malaria-endemic regions rarely survive more than two weeks. Therefore, the researchers sought to investigate ways to shorten the mosquito’s lifespan because "even a modest reduction in lifespan could significantly impact parasite transmission," the authors wrote in their paper, published online July 15 in PLoS Pathogens.
The researchers used information that has been learned by studying longevity and immunity in other model organisms, particularly fruit flies and nematodes, to target a gene in the mosquito suspected to control mosquito lifespan and regulate its resistance to infection. The team engineered the mosquitoes to express high levels of the active form of a protein known as Akt, and found that the transgenic mosquitoes not only had a shorter lifespan—approximately 20 percent shorter than controls—parasite infection was completely blocked.
"We were surprised how well this works," Riehle said, in a prepared statement. "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."
This is an important first step because it only takes one parasite to make a mosquito infective—if even a single parasite survives, it can go on to produce thousands of progeny, Riehle says. He adds that his team would like to figure out how the parasites are being killed because that information could be used to make even more resistant mosquitoes.
In order for any transgenic mosquito to be truly effective against malaria, however, the transgenic bugs will have to out-compete wild mosquitoes and eventually displace them, a significant challenge that Riehle acknowledges and hopes to tackle in the future. Until that happens, Riehle’s genetically modified mosquitoes are safely secured in his lab.
Image of a mosquito larva with a red fluorescent marker indicating that it has the genetic modification that makes it immune to the malaria parasite, courtesy of M. Riehle, University of Arizona
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The article states:
"In order for any transgenic mosquito to be truly effective against malaria, however, the transgenic bugs will have to out-compete wild mosquitoes and eventually displace them, a significant challenge that Riehle acknowledges and hopes to tackle in the future."
More precisely, the wild mosquitoes would either have to be completely eliminated or continuously out competed by the the transgenic variety.
Perhaps the only way to accomplish this is to engender some advantageous characteristic in the transgenic variety that could not be adopted by wild mosquitoes: perhaps higher rates of reproduction, for example.
Great care must be taken, of course, lest we inadvertently produce a super mosquito that devours humanity…
Link to thisI think the idea of genetically modifying mosquitos could be horrifically dangerous. What if the mosquito ‘fixes’ it’s dna to offset the genetic changes and actually becomes completly resistant to pesticides and other influences instead of disease. While a noble effort, I am not sure if this should be fully pursued. I speak as a victim, I got viral meningitis from a mosquito and nearly died from it. I am all for the elimination of mosquitos, not suplanting them with an unknown danger.
Link to thisI think the way to do this is to effectively carpet-bomb (with pesticides) endemic areas, reduce the native mosquito population, and then introduce the anti-malaria mosquitoes in large numbers, so that they fill in the niche that we just vacated for them. This way, one massive attack against mosquito populations should do the trick, since the new mosquitoes will replace the old ones. Of course, this won’t solve the problem of other mosquito-borne illnesses, so things like bed-nets will still be needed, but this could be a great start. So to summarize:
Link to this1) Make the anti-malaria trait heritable, preferably dominant
2) Mass-produce the anti-malaria mosquitoes, make billions of them
3) Destroy native mosquito populations in target areas with powerful but short-lived pesticides
4) Release anti-malaria mosquitoes into target area during the window of opportunity, after the pesticides wear-off but before native mosquito populations return
Result: Many malaria carrying mosquitoes are destroyed in the first wave, and subsequent generations of mosquito will be unable to transfer malaria at all. As the number of humans with malaria dwindles, the disease gradually becomes extinct over a few years/decades.
Hopefully this isn’t just science-fiction.
Ola,
Link to thisQuoi un moustique transgénique ! mais vous ne savez donc pas à quoi vous jouez !"sorceres apprentice "
Vous n’avez donc pas appris les leçons du passé ! De nos jours la science est devenue aveugle et sourde aux réalités de ce monde.
amazing science!
Link to thisI agree with capataz. But anyway, while you’re at it, you could make them so they get really big! Increase their growth rate so they out-compete and perhaps even eat the non-transgenic mosquito larva!
Link to thisThink of how much more effective such mosquitoes would be for transmitting Chikungunya, O’nyong’nyong, Dengue fever, Yellow fever, etc…..
Wonderful work!, but even if GM Mosquitoes do succeed in replacing old ones, how long will it take for plasmodia to mutate and re-infect the mosquito population? . The protection has no scape ways?
Link to this