Can genetically modified ‘killer mosquitoes’ stop the Zika virus?

News & Analysis

26th January 2016

The forecast for the Zika virus outbreak seems dire. There is no vaccine, and no hope of one for at least a year, probably longer. And, according to the World Health Organisation, it is likely to spread to every country in the Americas apart from Canada and Chile.

Women in El Salvador have already been told to leave off getting pregnant until 2018, as it seems likely the virus causes brain damage in infants. Of course, this does not seem very realistic.

While North and South Americans wait for a vaccine, the best hope may lie in targeting the Zika carriers: the mosquitoes. And scientists in Oxford have developed an extraordinarily deadly means of doing so.


A company called Oxitec, set up by scientists from Oxford University, has produced a form of genetically modified mosquito whose offspring do not survive. By releasing millions of these GM males into an area to mate with potentially virus-carrying females they can lower the mosquito population by nine-tenths in a matter of months. (The GM males die quickly too, having been programmed to survive on a special diet in a lab.)

Trials on the Aedes aegypti mosquito — the mosquito transmitting the Zika virus – have already been carried out in Brazil. The target of the trial was not Zika, but dengue fever, and in Eldorado, Sao Paolo, where the GM mosquitoes were released, the number of dengue cases dropped from 133 to just one in a year.

The Oxitec mosquitoes are still being reviewed by the US Food and Drug Administration and a plan to use them in Florida met fierce opposition following headlines about ‘genetically modified killer mosquitoes’.

If taken up by the governments of the Americas they could be a key weapon against the Zika virus, alongside more routine methods of mosquito-avoidance. The challenge will be to scale up their production quickly enough to make a difference.

In the longer term they may well be crucial in efforts to combat other mosquito-borne disease — dengue fever, chikungunya, yellow fever, malaria — by keeping the mosquito population at a very low level. It tentatively raises hopes that the mosquito may one day no longer be such a deadly enemy for humans.


  • Tickertapeguy

    Sometimes old technology works. Bring back DDT just for this occasion and eradicate this infected mosquito. After that has been accomplished then stop the use of DDT. We do not have the time for genetically engineered mosquitoes to stop the spread of this virus

  • Mary Ann

    It sounds a sensible idea to kill of the mosquitoes but they have their place in the food chain, are their any plans to encourage similar size insects to breed more freely so those animals and birds that eat mosquitoes at the moment will have something else to eat.

    • Emily

      Once there is mosquito depletion there will be more means for other insects to thrive without facing the competition.

      • Mary Ann

        Hopefully, but can’t help thinking about Cane Toads and Rabbits in Australia.

  • nats

    Illusion and deception – the devil’s work and your comments show that he does it well. If these mosquitos, which were already released in great numbers in 2011 and 2012 in Brazil would reduce the number of mosquitos there, then there would not have been an outbreak of Chikungunya nor ZIKA.

    The OPPOSITE is true: Releasing these GM mosquitos is actually the more likely reason for both CHIK V and ZIK V outbreaks originating from UK/ Brasilian GM mosquitos!!!! Releasing an impure, split being from impure devil technology into the natural, pure, whole, totally balanced, wiseful goddess-created environment this is what caused CHIK V and ZIK V outbreaks. That is if the GM mosquitos were not already infected when they released them!!!!

    In addition, if all mosquitos would disappear, there will be no food for fishes, lizards etc.

    The end plan of GM is total control over all food sources by spoiling natural environment and creating total dependency on big seed/ pharma conpanies. GM plants will spoil all existing, natural, goddess-created plants by bee and wind pollination and all indigenous, natural, non-GM plants will cease to be fertile and reproducable like it is already happening in many countries.

    • Needham’s M. Garden

      I am sure your rant would sound different if someone you cared for was involved.
      People like you are what is wrong with this world. Thankfully your kind are becoming a minority and science is winning the battle of minds.

    • schobes lala

      oh how wiseful your god created those mosquitos transferring all those deseases!

      the end plan is to allow even poor people to survive in areas where today many die young because of, for example, malaria. to let people in general live longer and more healthy. the world would already be a far more comfortable place to live if there were not so many religious fanatics like you who see the devil in science.