- Title: Scientists release sterile mosquitoes in Burkina to fight malaria
- Date: 18th September 2019
- Summary: RESEARCHER LOOKING AT MOSQUITO ON SCREEN MOSQUITO ON THE SCREEN FROM MICROSCOPE
- Embargoed: 2nd October 2019 11:14
- Keywords: genetically sterilized mosquitoes anti-malarial drugs Target Malaria gene drive
- Location: BOBO-DIOULASSO, SOUROUKOUDINGA, AND OUAGADOUGOU, BURKINA FASO
- City: BOBO-DIOULASSO, SOUROUKOUDINGA, AND OUAGADOUGOU, BURKINA FASO
- Country: Burkina Faso
- Topics: Health/Medicine
- Reuters ID: LVA002AX6QB13
- Aspect Ratio: 16:9
- Story Text: Scientists in Burkina Faso have deployed a new weapon in the fight against malaria, and waded into a thorny bioethics debate, by letting loose thousands of genetically sterilized mosquitoes.
Their experiment is the first outside the lab to release genetically altered mosquitoes in the hope of reducing their ability to spread the often deadly disease. It works using a technique called a gene drive, which edits and then propagates a gene in a population - in this case to prevent males from producing offspring.
Investments in anti-malarial drugs, mosquito nets and insecticides have slowed malaria over the past two decades in Africa, which accounts for more than 90% of global cases.
But malaria still killed more than 400,000 people across the continent in 2017, and the World Health Organization says progress against the disease is stalling, leading researchers to push for fresh approaches.
"The action of the enzyme continues after fertilization which means that when the male copulates with the female, the female gametes (germ cells that unites with the male to reproduce) which have all the X chromosomes, since the enzyme is still active, it attacks the X chromosomes and destroys them and as a result we end up with just the Y chromosomes, since all the X are destroyed. And if the male copulates with the female, the embryo is dead and the female can no longer have offspring," said Dr. Abdoulaye Diabate, who is running the experiment for Target Malaria, a research consortium backed by the Bill & Melinda Gates Foundation.
One hot evening in July, Diabate's researchers peeled off mesh nettings from wire-rimmed containers to release about 5,000 male mosquitoes into Souroukoudinga, a village in western Burkina Faso.
The mosquitoes had been injected as embryos with the enzyme that sterilizes them.
"The ultimate goal for Target Malaria is to develop a genetic fighting tool which is durable in the long term and affordable - that is cost efficient. So with this specific product, the goal is to release it in the field in the long term and to see the gene of specific interest spread across different mosquito populations and to reduce the density of these mosquitoes one way or another," Diabete added.
Target Malaria is also developing an enzyme preventing male mosquitoes from passing on X chromosomes. This results in male offspring, reducing malaria since only female mosquitoes bite - males mostly feed off plant honeydew.
Diabate said he hoped the new approaches would win approval from national regulators in the coming years for widespread use, using a gene drive proved effective in lab experiments at Imperial College London, where researchers last year said they had succeeded in wiping out populations of caged mosquitoes within 11 generations.
Activists in Burkina fear unintended environmental consequences.
"The future is very uncertain with these mosquitoes, the future is even catastrophic, the future is dark. Imagine these modified mosquitoes that are going to be unleashed on nature, (they) may be able to release pathogens, to release viruses which under normal circumstances they would not be able to harbor. It is an entire population that will be decimated, a whole eco-system that will be decimated and it can even go beyond the borders of Burkina (Faso)," said Ali Tapsoba of the 'Terre De Vie' environmental group.
Those concerns echo beyond Burkina. Last November, signatories of a United Nations convention on biodiversity noted "uncertainties regarding engineered gene drives."
Critics of gene drives fear they could be used to manipulate human genetics, or develop a bio-weapon.
Researchers in Brazil have also released genetically modified mosquitoes in an attempt to control diseases like yellow fever and Zika, but it is not clear how effective that has been.
Target Malaria says it consults with communities and that research is overseen by national regulatory authorities and an independent ethics committee.
"African children have been dying of malaria for years, practically since pre-historic times and every year, systematically, when you look at the statistics, you realize that our ability to impact on the transmission of malaria is stagnating. The convectional tools at our disposal today have reached a ceiling and can't become more efficient than they are at the moment. So we have no choice but to look at complimentary methods and that is why we are using genetically modified mosquitoes as a way of exploring this new avenue," Diabete said.
Two months after the mosquitoes were released, Souroukoudinga chief Pascal Traore told Reuters villagers were happy with the experiment's progress.
"We all believe that the project could reduce the malaria that kills our sons and daughters," he said. "This project is not just for us, but for the entire world."
(Thiam Ndiaga, Christophe Van Der Perre, Yvonne Bell) - Copyright Holder: REUTERS
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