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Genetically-engineered mosquitoes can't transmit malaria

By

June 13, 2012

Scientists have created genetically-modified mosquitoes that are incapable of spreading ma...

Scientists have created genetically-modified mosquitoes that are incapable of spreading malaria

Last year, Prof. Anthony James announced that he and his colleagues had genetically altered Aedes aegypti mosquitoes in a fashion that could drastically reduce their populations. In a nutshell, the altered genes cause the female mosquitoes to be born without wings – this makes it rather difficult for them to go foraging for blood, and turns them into easy prey for almost any predator. The non-biting males are born with wings, and subsequently go off and mate with unmodified females, passing the modified genes along to their offspring. Now, James has done some more genetic engineering, to create mosquitoes that can’t spread malaria.

The University of California, Irvine molecular biologist worked with colleagues from both UC Irvine, and the Pasteur Institute in Paris.

They started with mice that were infected with the Plasmodium falciparum parasite, which causes malaria. Those mice created antibodies in order to kill the parasites. The scientists identified the molecular components of this immune response, then altered the genes of the Anopheles stephensi mosquito in order to cause the same response to occur in their bodies – ordinarily, mosquitoes simply act as carriers of the parasites, exhibiting no immune response towards them.

In short, parasites picked up by the mosquitoes are killed by the insects’ altered immune systems, meaning that people subsequently bitten by those mosquitoes won’t develop malaria. Although the study was done using Anopheles stephensi, the technique could reportedly be used on dozens of different types of mosquitoes.

Unlike James’ previous efforts involving the flightless females, this approach would not actually reduce the numbers of mosquitoes present in an area. Much as many people might like the idea of the eradication of mosquitoes, this could be a good thing – it’s still unclear how the sudden elimination of a species as plentiful as the mosquito might affect ecosystems. That said, of course, the wisdom of releasing genetically modified mosquitoes to breed with wild populations might also be questioned.

Given that approximately one million people die worldwide every year from malaria – which is spread mostly by mosquitoes – it’s a risk that some people may be willing to take. “We see a complete deletion of the infectious version of the malaria parasite,” said James. “This blocking process within the insect that carries malaria can help significantly reduce human sickness and death.”

A paper on his research was published this week in the journal Proceedings of the National Academy of Sciences.

Source: University of California, Irvine

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
16 Comments

This has been coming for quite a while and is a welcome development. Now to the tricky issue of when they are released into the broader population.

SteveP
13th June, 2012 @ 09:24 pm PDT

Can Prof James modify them so they don't make that annoying whining noise when they're flying? :-)

agulesin
14th June, 2012 @ 05:52 am PDT

As much as I hate mosquitoes, wouldn't this remove one of the largest food supplies of bats?

Billy Sharpstick
14th June, 2012 @ 09:11 am PDT

I am not a biology major but think I have a layman's understanding of the "birds and the bees" or in this case mosquitoes. How is it that starving the females does not reduce or eradicate the population? The males don't suck blood so they can't even bring the girls takeout. What do the males eat anyway?

MintHenryJ
14th June, 2012 @ 09:36 am PDT

If this is successful, it's Nobel Prize worthy...

Matt Rings
14th June, 2012 @ 09:44 am PDT

MintHenryJ, mosquitoes feed on nectar. Females only need a blood meal to produce eggs.

Arf
14th June, 2012 @ 10:06 am PDT

Releasing GMO organisms into the environment could be extremely risky. In Maine they controlled mosquitoes naturally by releasing drangonflies (mosquito hawks).

ezeflyer
14th June, 2012 @ 10:24 am PDT

Wouldn't it make more since to fix the protein deficiency that requires female mosquitoes to suck blood to lay eggs.

Slowburn
14th June, 2012 @ 01:04 pm PDT

Of course dramatically reduce the mosquito population and everything that relies on eating them will die off too... so fewer birds, amphibians.. and then those that eat those species will have issues...

And if there are other unintended consequences of genetic engineering we might get really good at spreading around a mutated malaria that is worse...

Bad idea as much as I'd like to reduce being bitten by the things or have less malaria in the world.

kidsandliz
14th June, 2012 @ 01:08 pm PDT

THIS WILL NOT DECREASE THE MOSQUITO POPULATION. Here is the explanation as to why:

Normally the males are wingless, and the females fly. Here they are swapping which one has the wings. Just as many males will now fly, as females that they are replacing. But the males do not suck blood. So those males will not be transmitting any disease, regardless. The females will still suck blood, but have the antibodies to kill the malaria, but since they can't fly it isn't a huge help. However, since the males can fly, they can go mate with the non-gmo females that CAN fly, and thus pass on either the trait that swaps who has the wings AND/OR makes them have antibodies, OR BOTH. So even with genetic switching, both traits would be useful. We NEED mosquitos out there in the environment because stuff lives off of them, but it the ones flying around didn't bite people, then it wouldn't matter if there were lots of them. This way we would be able to have lots of mosquitos, and far less Malaria. It would also tip the scales fairly quickly that the males are able to fly to the females because then the genetically altered males will have a higher rate of mating than the non-flying males.

This is genius.

Isabelle
15th June, 2012 @ 12:20 am PDT

I want wings :)

It would be handy if they could GM the females to have their blood storage glands also saturating their protein stores with a host of anti-viral/ anti-bacterial bio-chemicals or and / or anti-malaria vacines.

So what used to give you malaria is actually giving you a vaccine (from others which may still do !)

Andrew Kubicki
15th June, 2012 @ 12:54 am PDT

Isabelle - I don't think the article suggests that they would do both modifications; either one is enough.

As for concerns about whether to release GM mozzies, Elvis left the building with the scandalous secret release of millions of GM mosquitoes in Grand Cayman in 2009:

http://www.spiegel.de/international/world/genetically-modified-pests-the-controversial-release-of-suicide-mosquitoes-a-812283.html

For ecosystem impact, discussion I've seen seems to suggest that it would be small, since these alterations only affect one of many very similar (but not disease carrying) mosquito species: others would simply expand to fill the void, and the insectivores concerned are apparently not very fussy eaters. We're not talking cane toads here.

Whether good or bad, Grand Cayman will prove interesting.

Synchro
15th June, 2012 @ 11:55 am PDT

Preventing mosquitoes from transmitting malaria is a much better option than preventing them from reproducing as easily. Mosquitoes are an integral low part of the food chain in many tropical areas; mess with them, and you mess with an immense number of other plant and animal species that directly and indirectly benefit from feeding on mosquitoes.

That said, unless the mosquitoes' immune response is 100% effective against malaria, the eventuality of this modification is that malaria parasites will adapt to work even further under the mosquitoes' radar, or resist the insects' immune response long enough to find a mammalian host. Let's hope this modification will be effective.

Joel Detrow
15th June, 2012 @ 02:00 pm PDT

In order for this to really be effective the modifications they make must be beneficial to the mosquitoes, otherwise there will be no positive selective pressure on those genes. If the parasite actually harms the mosquitoes, then making them immune to them would be a fantastic benefit. Otherwise, it'll spread purely by genetic drift.

Nathaniel Summers
17th June, 2012 @ 05:52 am PDT

Really? This is not the way to spend research dollars! They are parasites, kill them! They do little to aid the environment anyway.

Norm Harding
18th June, 2012 @ 06:03 pm PDT

@ Isabelle you propose an interesting scenario.

A controlled scientific trial should be conducted to determine if the hypothesis is correct, or not. Before a uncontrolled environmental trial, like a remote island, should be conducted most, if not all, the variations or mutations should be considered.

Since this GMO is species-specific there should not be cross-over within the Family of mosquitoes, or other Diptera. It would be great if science can control, or possibly eliminate malaria, yellow and dengue fevers, West Nile virus and tularemia.

Ecological impact? Since this will be gradual, the insectivores will just select another insect that is available, unless mosquitoes are 100% of the flying insect population.

Nobel Prize, you bet !!!

BombR76
26th June, 2012 @ 11:07 am PDT
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