Gene-editing technologies that alter mosquitoes' DNA could prove critical in the fight against malaria, Bill Gates said on Wednesday, and ethical concerns should not block progress in such gene-modifying research. Speaking at the Malaria Forum conference in London, the billionaire Microsoft co-founder and philanthropist said that while gene editing raises "legitimate questions", that should not jeopardise exploration of tools such as CRISPR gene editing and so-called "gene drive" technologies.
"I'm very energised about the potential of gene drive. (It's) the kind of breakthrough we need to support," Gates said. "It may prove critical here." Gene drive technologies alter DNA and drive self-sustaining genetic changes through multiple generations by overriding normal biological processes. CRISPR technology enables scientists to find and modify or replace virtually any gene.
The techniques are being explored across science - from human medicine to livestock- and crop-breeding. In mosquitoes that transmit malaria, genetic alterations can be used to induce infertility to reduce populations, or alter the insects' ability to carry and pass on the malaria parasite. The technologies can be extremely powerful, but they are also controversial, since such genetically engineered organisms released into the environment could have an unknown and irreversible impact on the ecosystem.
Asked in a interview with Reuters about that controversy, Gates said there were understandable concerns about safety and efficacy that would need to be addressed in research and trials. But he countered: "Malaria itself is quite controversial - it kills about 400,000 kids a year. So we're definitely not on the side of malaria."
He also noted that at their summit in January, leaders of the African Union endorsed gene drive research as part of the fight against a disease that continues to kill their people. "They spoke out to say that, for them, getting rid of malaria is worth using innovative science," Gates said. The World Health Organization (WHO) warned late last year that global progress against malaria had stalled and could be reversed if momentum in the fight to wipe it out was lost.
The disease infected around 216 million people in 91 countries in 2016, an increase of 5 million cases over the previous year. It killed 445,000 people, about the same number as in 2015, with the vast majority of deaths occurring in babies and young children in sub-Saharan Africa. Gates told the Forum that his almost 20 years of involvement in global efforts to beat malaria had been both gratifying, in terms of progress, and tough, in terms of suffering he witnessed.
He described seeing a child in a hospital in Tanzania convulsed with seizures due to cerebral malaria. "With the state of science and the wealth of the world, that really should be an affront," he said. "We really shouldn't accept that this disease can continue." Gates said that ending malaria for good would take many years and a range of tools both new and old - from bednets and mosquito traps to a new vaccine and next generation gene tools.
He said he thought it unlikely that creating gene drives in malaria-spreading mosquitoes would have a major impact on the wider ecosystem because it would only target a few species and suppress their populations for a period of time.
"None of these (gene technology) constructs will actually wipe out the species," he said. "It will evolve back. After all, evolutionary pressures always push back."
Dramatically reducing mosquito populations with such technologies could, however, give a window of opportunity to help limit the human reservoir of disease so that transmission of the disease among people is stopped, he said.
Gates also said genetic information and data, gathered in the field and transmitted swiftly to sophisticated surveillance systems, is allowing scientists to identify evolving strains of malaria parasites and track drug and pesticide resistance, helping them stay one step ahead of the disease.
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