GM Mosquitoes Bred To Tackle Dengue FeverTweet

Millions of genetically modified mosquitoes are being released into the wild in the Brazilian city of Juazeiro to try to wipe out dengue fever.



The dengue fever-spreading mosquito

The viral disease affects between 50 and 100 million people a year.

While symptoms of the illness - which occurs in tropical climates - are usually mild, around 1 in 20 people will become seriously ill.

Currently, there is no vaccine and no treatment, so the only way to fight the disease is to destroy the mosquitoes that carry it.

Up until now, pesticides have been used to kill them, but they are becoming increasingly resistant.

This latest experiment means, if successful, the mosquitoes will be removed from the "cleansed" area and the dengue fever prevented from spreading.

The plan, reported in the New Scientist, is for the GM mosquitoes to mate with the natural mosquito to create offspring that die before reaching adulthood because of their infected genes.

That would make them incapable of spreading the disease.

If it works, the scheme could be used on other unwanted pests.



A world map showing where dengue fever is prevalent

The method has already been used elsewhere, according to the report, having helped to eliminate the screwworm fly from the US and the tsetse fly - known for being linked to the deadly sleeping sickness - in Zanzibar.

Enthusiasts of the GM model say such an approach is effective because it focuses only on the species to be controlled, whereas pesticides harm other species in the chain, including humans.

In answer to critics wondering about the "unnatural" way of dealing with nature, Michael Le Page of the New Scientist told Sky News: "The dengue-carrying mosquito Aedes aegypti is native to Africa and has been spread around the world by humans.

"So eliminating it in Brazil can be seen as restoring the natural ecosystem. 

"In most areas, there are several mosquito species, so wiping out one wouldn't make much difference.

"As far as causing long-term damage is concerned, the GM mosquitoes affect only their own species, and their effect would end soon once they were no longer released.
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