Malaria is one of the world's deadliest diseases, killing hundreds of thousands of people every year, mostly children under five.
The disease is caused by a parasite that is transmitted by Anopheles gambiae, the main mosquito vector in Africa.
To prevent malaria, scientists are developing new genetic technologies to edit the mosquitoes and stop them from spreading the parasite.
One such technology, called Ifegenia, was recently reported by researchers at the University of California San Diego and their collaborators.
How Ifegenia works
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Ifegenia is a system that uses CRISPR-Cas9, a gene editing tool that can make precise cuts in DNA. The system targets a gene called femaleless (fle), which is essential for the development of female mosquitoes, as per Phys.org.
By disrupting this gene, Ifegenia kills female mosquitoes, which are the ones that bite and transmit malaria.
Male mosquitoes, on the other hand, inherit Ifegenia but are not affected by it. They can still mate and pass on the system to their offspring.
The researchers created two strains of genetically modified A. gambiae mosquitoes, one that expresses Cas9, the enzyme that cuts DNA, and another that expresses a guide RNA, a molecule that directs Cas9 to the fle gene.
When these two strains are crossed, their offspring inherit both Cas9 and the guide RNA, which together cause a fatal mutation in the fle gene.
The researchers tested Ifegenia in laboratory cages and found that it was very effective in eliminating female mosquitoes and suppressing the population. They also showed that Ifegenia was stable and did not lose its activity over multiple generations.
Why Ifegenia is promising
Ifegenia is a promising technology for malaria control because it is simple, safe, and scalable. It is simple because it only requires Cas9 and the guide RNA.
It is safe because it does not introduce any foreign genes or toxins into the mosquitoes or the environment.
It only targets a gene that is specific to A. gambiae and does not affect other species. It is scalable because it can spread through natural mating and does not require any external intervention or maintenance.
Ifegenia could potentially be deployed in malaria-endemic regions to reduce or eliminate the mosquito vector and break the cycle of transmission.
This could save millions of lives and improve the economic and social conditions of affected communities.
However, before Ifegenia can be used in the field, it needs to undergo further testing and evaluation to ensure its safety and efficacy. It also needs to be approved by regulatory authorities and accepted by local stakeholders.
Ifegenia is not the only genetic technology being developed to combat malaria. Other approaches include modifying mosquitoes to make them resistant to the parasite or sterile.
These technologies could complement each other and provide multiple options for malaria control.
Other strategies for malaria prevention and control
Besides genetic technologies, there are other strategies for preventing and controlling malaria, such as avoiding mosquito bites, using insecticide-treated nets and indoor residual spraying, taking antimalarial drugs prophylactically or therapeutically, diagnosing and treating malaria cases promptly, and developing an effective vaccine.
Some of these strategies are more feasible and accessible than others depending on the availability of resources, infrastructure, health systems, and community engagement.
For example, insecticide-treated nets are widely distributed and used in many African countries where malaria is endemic.
However, some mosquitoes have developed resistance to insecticides, reducing their effectiveness.
Antimalarial drugs are also widely available and affordable in many regions, but drug resistance is a major challenge that threatens their efficacy.
Diagnosing and treating malaria cases promptly can reduce morbidity and mortality, but access to healthcare facilities and trained personnel may be limited in some areas.
Developing an effective vaccine against malaria has been a long-standing goal of many researchers, but so far only one vaccine candidate has been approved for pilot implementation in three African countries.
Therefore, there is no single solution for malaria prevention and control. A combination of different strategies may be needed depending on the local context and epidemiology of malaria.
Genetic technologies, such as Ifegenia, may offer a new tool to complement existing interventions and achieve a greater impact in reducing the malaria burden.
