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The genetically modified "spawning" mosquitoes feed on the warm blood of the cow. Scientists hope that these mosquitoes could help eradicate malaria.

Pierre Kattar for NPR

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Pierre Kattar for NPR

The genetically modified "spawning" mosquitoes feed on the warm blood of the cow. Scientists hope that these mosquitoes could help eradicate malaria.

Pierre Kattar for NPR

In February, scientists started releasing genetically modified mosquitoes in a high-security laboratory in Terni, Italy.

NPR was the only news organization allowed to visit the lab to attend the first publications. Correspondent Rob Stein said at the beginning of the experiment: "Scientists release controversial genetically modified mosquitoes in a high-security laboratory".

The insects handled carry a deadly genetic mutation for the species. And this could prove to be a powerful weapon in the war against malaria. But as with all genetic modifications, unintended consequences are a source of concern.

We asked readers to share their questions about this experiment with genetically modified mosquitoes. Nearly 300 questions were submitted on topics ranging from its potential impact on the food chain to alternative solutions such as the development of a malaria vaccine.

Here are some of the most frequently asked questions that Rob Stein answered.

What happens to all other species in the food chain, such as bats and birds, which rely on mosquitoes as a food source? And what about their role as pollinators?

Deborah Kroll

Mosquitoes play an important role in the food chain. The bats eat them. The same goes for birds, fish, frogs and other animals.

But there are hundreds of mosquito species. So many scientists think that removing completely, if not completely, one would not have a significant impact on the food chain. Many other mosquito species would still be available for these animals.

Mosquitoes are also pollinators. But, again, the idea is that other species of mosquitoes and other insects would not be affected and would remain in the environment to play that role in the ecosystem.

Scientists say that research conducted to date indicates that the mosquito targeted, Anopheles gambiae, is not a "keystone" species – meaning that its disappearance would not have a significant negative ecological effect.

But these are all important questions that scientists involved in the Target Malaria project, which is developing a new type of modified mosquito, say they are intensively studying and need to understand better before considering any dissemination. Critics say ecosystems are too complicated to be safe forever.

If modified females can not lay, how does the mutation spread? Doug Wheeler

Female mosquitoes only become sterile when they inherit two copies of the mutation introduced into the mosquitoes using the CRISPR gene modification technique and a DNA sequence called "gene reader". This allows females to transmit a mutation of the gene to future generations of offspring and mate them with unmodified counterparts.

The idea is that local populations of this mosquito species will eventually collapse or even shrink dramatically, once enough females have inherited two copies of the mutation, rendering the populations unable to provide for it. their needs. During tests conducted in small cages in London, unmodified mosquito populations crashed in the space of seven to eleven generations, which took about six months.

Would not it be better to spend all this time and money to develop a vaccine against malaria? Anonymous

Scientists have spent decades trying to develop an effective vaccine against malaria. But the life cycle of the malaria parasite has made success elusive. The vaccine developed is only partially effective. Thus, while work continues to develop better vaccines, many scientists believe that other approaches are essential, especially as malaria continues to wreak havoc every year: about 212 million cases and 429 000 deaths . And efforts to reduce malaria using other approaches, such as treated mosquito nets, appear to have plateaued in some places.

What are the main arguments against this approach? Manuel (no last name)

There are two. The first is that "gene transmissions" are too dangerous because ecosystems are so complex that it is impossible to predict what would happen if an organism designed with gene transfer was released into the wild. The concern is that these genetically modified organisms could have a myriad of unforeseen and unforeseen consequences.

One fear, for example, is that drastically suppressing or even eradicating one species of mosquito could create a niche in the ecosystem that would allow another species to carry other health problems with it, perhaps even more dangerous. like other diseases transmitted by insects.

The other argument of the critics is that there are other less worrying alternatives that could be used to fight malaria, such as improving water supply systems and sewage systems so they do not do not serve fertile ground for mosquitoes. Scientists argue that the modified genes approach to mosquitoes is actually much more focused than the traditionally used approach – the large-scale use of pesticides, which causes much greater ecological damage than the elimination of a single species of mosquito.

Who facilitates public discussions in African villages? Is it a neutral third party?Anonymous

Target Malaria has announced the establishment of a broad awareness program for some time to develop this program in close consultation with national governments and local community leaders where future dissemination may take place. This includes Burkina Faso, Uganda and Mali.

The project organizers say they are actively working to inform the inhabitants of these places about this technology. This dissemination will only occur if it is clear that the local population has been truly informed of the benefits and risks, and there is a broad consensus that this would be the case. acceptable.

Critics, however, question whether the program actually gets informed consent, saying local residents do not seem to have been well informed and have deep reservations about the project.

Do you think this GMO experiment could be replicated with other natural parasites such as ticks, fleas and some invasive species? Noelle Marasheski

Scientists are very interested in this approach to fight against other problems caused by insects and other creatures. Scientists at the University of California at Davis, for example, are working to use CRISPR and gene readers to control a fruit fly species that is a major problem for farmers growing crops such as berries, as well as other mosquito species that spread elsewhere. diseases, such as Zika.

Other scientists are working on the development of a related approach to control Lyme disease, carried by ticks and possibly to control invasive rodents that damage fragile island ecosystems in New Zealand, Hawaii and other parts of the world. elsewhere.

Thank you to everyone who participated in our call. Follow Rob Stein on Twitter at @robsteinnews follow his coverage of this topic and more.

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