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Is genetic modification of anophelines the way to start elimination of malaria?

January 27, 2016 - 18:48 -- William Jobin

From the recent reports out of California and other places, it appears that anophelines can be genetically modified so that (1) they are no longer susceptible to plasmodium infections, and (2) their progeny will be all males! If this can be developed for field use, it looks to me like it is the Beginning of the End of malaria in Africa. But I am an engineer with no experience in genetics. Do you think that this technique can be developed for field application?

To quote the New York Times Science section of 22 December, “A gene drive designed to render a population extinct is known as a crash drive. A crash drive being developed for mosquitoes consists of a gene engineered into the Y chromosome that shreds the X chromosome in the cells that make the mosquito’s sperm, thus ensuring that all progeny are male. Unless the drive itself is damaged through mutation, the number of females would be expected to dwindle each generation until the population collapses….”

So I think this would result first in reduction in the number of females, and thus reduction in transmission. If continued, it would then mean local elimination of the species being modified.

The NY Times article refers to a difficult to read report in:

Proceedings of the National Academy of Sciences in USA, 2015 Dec 8;112(49):E6736-43. doi: 10.1073/pnas.1521077112. Epub 2015 Nov 23.
Highly efficient Cas9-mediated gene drive for population modification of the malaria vector mosquito Anopheles stephensi, by Gantz VM, Jasinskiene N, Tatarenkova O, Fazekas A, Macias VM, Bier E, James AA.

Bill, hoping

Comments

Submitted by Graham Matthews (not verified) on

Hi Bill, There is some success with the system of GM mosquitoes developed by Oxitec with Aedes aegypti and expansion of the technique taking place in Brazil. However with malaria, there are usually several different species of Anopheles in one place so the release of A. gambiae for example will have to be followed by GM technology for other species. To release sufficient, I think a vast area wide application of a cold fog non-persistent insecticide will be needed to decrease the natural population so that the number of GM mosquitoes needed to be released is manageable. Who knows?
The problem today is to get the non-chemical old techniques done, drainage and house improvement as part of IVM, especially as resistance to pyrethroids is already widespread.

Submitted by Anonymized User (not verified) on

The exuberance around these systems (even with gene drives) seems to ignore one iron rule- evolution always wins in the end.

The tested systems lead to a 99% reduction- just like DDT did (at first)- and that 1% is the key. Sure it works in a short-to-medium term fashion, but it absolutely will fail.

And as mentioned above, with 30+ major vector species, each single one will have to be developed, tested, and approved individually before use. Certainly An gambiae, funestus, and arabiensis will be the first, but a cautionary tale in brand new vector species in W Kenya:

http://www.ajtmh.org/content/early/2016/01/14/ajtmh.16-0020.full.pdf

Submitted by Anonymized User (not verified) on

Read the following on wordpress

"Who benefits from this Zika “science”? Certainly, the people who are releasing genetically engineered (GE) mosquitos as a form of disease-prevention. The big honcho is a company named Oxitec. So far, the GE mosquitos are being used to curtail dengue fever in Brazil, Malaysia, and the Cayman Islands. Florida is next up on the agenda. But with Zika coming on strong in the press as a “mosquito-carried plague,” how long will it be before special bugs are modified to save the planet from this new threat…

Just a few problems with the GE mosquitos, though.

A town in Brazil has reported continuing elevated levels of dengue fever since the GE (genetically engineered) mosquitoes have been introduced to combat that disease.

The scientific hypothesis is: the trickster GE bugs (males) will impregnate natural females, but no actual next generation will occur beyond the larval stage. However, this plummeting birth rate in mosquitoes is the only “proof” that the grand experiment is safe. No long-term health studies have been done

Needless to say, without extensive lab testing, there is no way to tell what these GE mosquitoes are actually harboring, in addition to what researchers claim. That’s a major red flag.

Wherever these GE mosquitoes have been introduced, or are about to be introduced, the human populations have not been consulted for their permission. It’s all being done by government and corporate edict. It’s human experimentation on a grand scale.

There are concerns that, if indeed the dengue-carrying mosquitos are actually wiped out, the vacuum may be filled by another dengue carrier, the Asian Tiger Mosquito—which breeds much faster.

Other than that, everything is perfect. Let’s have a big parade and welcome genetically-engineered mosquitos to planet Earth.

Nestor

Submitted by Bill Jobin (not verified) on

Thank you Graham, Nestor and my anonymous friend.
In general, I agree with all your comments, altho I don't see the analogy between GM of mosquitoes and DDT resistance. But what all three of you point out is that this approach will take a long time, as we have multiple anopheline species to deal with.
So it won't happen overnight, and we are already facing resistance to pyrethroids and to artemisin drugs. So in the meantime.....

Maybe we have to start adding environmental and ecological approaches, such as filling and draining swamps, and screening houses with improved eaves and walls. Although we have repeatedly urged Tim Ziemer at the US PMI to do this, he seems to be waiting for the whole program to collapse before he will add such obvious measures.
On the other hand, if GM offers such promise, shouldn't WHO be chasing it? Shouldn't Pedro Alonso convene an Expert Committee and get things going fast?
Bill