The first results of the release of sterile specimens are very encouraging.
Climate change is favoring the spread of mosquitoes
Malaria is one of the great evils facing the world in terms of health: close to 250 million cases on the planet each yearcausing more than 600,000 deaths, 96% in Africa. 80% of the deceased are children.. The fight against malaria is an absolute priority for health authorities and for the World Health Organization (WHO). One of the measures being studied is the loose of mosquitoes genetically modified to be sterile.
On July 1, 2019, the Institute for Research in Health Sciences (IRSS), in the town of Bobo-Dioulasso, in Burkina Faso, carried out the first release of genetically modified mosquitoes in Africa as part of the ‘Target Malaria’ project.
This small-scale release marked an important step in the general path of research for the development of a anti-malaria genetic technology.
The genetically modified mosquito colony, provided in the form of eggs by the Terni Genomic, Genetic and Biological Innovation Pole (GGB Pole), in Italy, was established and studied by the medical entomology team in the IRSS insectarium.
After the pertinent studies, the IRSS prepared and submitted a controlled release application that was approved by the National Biosafety Authority (ANB) of Burkina Faso. After the release, seven months of continuous monitoring allowed the team to draw scientific conclusions about the survival and behavior of the modified mosquitoes..
This phase was essential for gathering information, sharing the research steps with stakeholders, working with authorities, transferring knowledge and building local skills. The objective was neither to control the density of mosquitoes nor to influence the transmission of malaria… for now
Eggs that don’t hatch
The first phase of the research programapproved by the local community of Bana, the place where the release took place, consisted of experimenting with a sterile male mosquito strain without gene drives. When these mosquitoes mate with females, the eggs they lay do not hatch.
On July 1, 2019, some 6,400 genetically modified male mosquitoes and approximately 8,500 non-GM male mosquitoes were released as part of a comparative study of ‘mark-release-recapture’ (MRR).
All mosquitoes were marked with a fluorescent powder to distinguish them from wild ones and to facilitate their identification during recapture. Molecular diagnostics was also used to identify the modified mosquitoes.
The intensive MRR study lasted 20 days and was followed by seven months of follow-up to verify the disappearance of the transgene from the environment.
The results of this study were consistent with expectations. For example, sterile male mosquitoes were recaptured in swarmsshowing that they can engage in swarming activities (important for reproduction) in a similar way to wild mosquitoes.
Further: sterile male mosquitoes were recaptured inside houseswhich shows that, like wild males, they sometimes prefer to take refuge inside houses.
Male sterile non-gene drive mosquitoes did not disperse beyond the boundaries of the release village, and were comparatively less mobile than wild mosquitoes released.
The survival of the released insects was also estimated. Sterile male mosquitoes did not survive as long as their unmodified counterparts. released.
male bias
The next phase of the project will be what they call ‘non-genic male bias’: the release of mosquitoes without a genetic drive but carrying a genetic modification that results in fertile males that produce predominantly male offspring.
When these modified males mate with wild females, the modification is passed on to half of their offspring. The strain does not have any fitness advantage or biased inheritance from the modification, so if released into the field, mosquitoes would disappear in a limited number of generations.
“The research is still in its early stages and, although the initial results look promising, there is still a long way to go,” the scientists acknowledge.
“As a last resort, we hope to develop mosquitoes that carry an element that reduces the transmission of malaria. Gene-drive mosquitoes could therefore be a powerful tool to control malaria in Africa that would complement existing vector control methods,” the researchers note.
“At the end of our research programme, if the gene drive technology proves to be reliable, safe, effective and sustainable, and if it is approved by national regulatory authorities, local communities and other potentially affected stakeholders, it will be made available for use. in malaria-affected countries through an open access agreement,” they announce.
Target Malaria’s goal is to build a forum for dialogue, trust and exchange between communities, civil society and all stakeholders in support of scientific progress. “Our vision is contribute to a world free of malaria“, highlight those responsible for this non-profit research consortium.
The favorable and enabling environment that the project has experienced in Burkina Faso is very encouraging. For now, Target Malaria has not foreseen any release of self-sustaining genetic change-driver mosquitoes, unaware what impact they could have on the ecosystem.
Target Malaria website: https://targetmalaria.org/
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Contact of the Environment section: [email protected]