Researchers have reached an important milestone in the fight against malaria. A paper published this week in the scientific journal Nature Biotechnology details how gene editing was used to wipe out a caged colony of malaria-transmitting mosquitoes.
The successful experiment was conducted by a team of researchers at Imperial College London led by Professor Andrea Crisanti. By modifying a section of the doublesex gene (which determines the gender of the organism), the team were able to essentially switch off the reproductive abilities of some female mosquitoes.
Two copies of the edited gene were required to block reproduction successfully. Male carriers showed no change, while female insects with only one copy also developed normally. However, the scientists found that the gene was successfully passed on to offspring almost all of the time. It therefore only took between seven and eleven generations for the separately caged populations to die out.
The eventual goal of the study is to determine if it’s feasible to release genetically edited mosquitoes into areas affected by malaria in the hope that the gene will be transmitted far and wide enough to drive down, is not completely eradicate, the general mosquito population. The experiment was conducted on the mosquito Anopheles gambiae species which spreads malaria in sub-Saharan Africa.
Malaria was responsible for 445,000 deaths worldwide in 2016 alone with 216 million cases reported. It is especially dangerous for infants and young children, causing fevers, vomiting, seizures and comas in some cases. It is passed from infected person to infected person via the saliva of female mosquitoes of the Anopheles genus when they feed off human blood.
The World Health Organisation (WHO) has raised concerns that heroic global efforts to fight the disease have slowed down in recent years and that infection rates have begun to creep back up as a result. This month the UN General Assembly passed a new resolution encouraging member states to provide ‘universal access to existing life-saving tools for the prevention, diagnosis and treatment of malaria’. The Imperial team hopes that their research will offer a new way to fight the disease in the near future.
While the initial results are encouraging, the genetically modified mosquitoes won’t be released to spread their genes any time soon. Another 5 to 10 years of studies are needed to ensure that the technology works at scale.
It remains to be seen whether different, less scientifically controlled environments affect the staying power of the mutation. A greater choice of mates in a larger mosquito population, coupled with the need to compete for resources like food, could conceivably impact the efficacy of this genetic solution.
There are also concerns about the wider environmental impact of artificially controlling the mosquito population. Some campaigners argue that research should focus on controlling and curing the disease itself, rather than eradicating its carrier.
Read more about Cimon Robot here.