CRISPR gene drives are a promising cure for malaria reduction and we should be optimistic about its future says Varsha Shankar
Malaria is one of the deadliest diseases in the world, affecting 220 million people every year and killing 400,000. In fact, Malaria disproportionately affects young people, taking the lives of 1,500 a day.
Malaria is caused by the plasmodium parasite. Mosquitoes infected with the parasite bite humans, infecting humans’ liver and red blood cells, compromising the immune system. When another mosquito bites the person, spreads the virus to more people and so on. Malaria is most common in sub-Saharan Africa but also is prevalent in South Asia, the Middle East, and other countries with large mosquito populations.
Many medications have been used to treat Malaria in the past. However, all of them have only achieved limited success. In recent years, CRISPR gene drives have been an area of interest in the malaria treatment realm. Recently, the WHO recommended the groundbreaking RTS, S vaccine for children with malaria. While it is very promising and offers hope for the future of malaria, it may not be able to eliminate malaria as a disease as efficiently, which is what Gene drives aim to do.
Why do our voices matter?
Malaria impacts young people disproportionately, especially those living in nations in the Global South. If youth around the world do not speak up for those most vulnerable, who will? Gene drive development will take a back seat and funding for the necessary facilities will be compromised if we do not stand up for fellow young people around the world. It is vital that we all use our collective voices for the young people suffering from Malaria and raise awareness of this cutting-edge solution.
How does CRISPR work?
CRISPR is a gene-editing technology that has had a significant impact on cancer treatments and other medical innovations. It has recently been a subject of research for Malaria cures.
For Malaria, CRISPR is proposed to be utilized in the form of gene drives. Gene drives are a relatively new topic and it is an open area of research with limited literature. But let’s talk about what we know.
What are gene drives?
Gene drives utilize CRISPR to insert and spread genetic modifications through a population at an abnormally high rate. Since 2014, scientists have engineered CRISPR-based gene-drive systems in mosquitoes, fruit flies and fungi, and are currently developing them in mice. Trials with mammals generally report a 70-75% success rate in accurate gene drive copying. Although there is much research necessary, gene drives are on the path to success.
How do CRISPR gene drives impact malaria treatment?
There are 2 main proposed ways to insert gene drives into the mosquitoes.
First, population control. This is where the drives are designed to spread female infertility due to alteration of the doublesex gene, where female mosquitoes cannot reproduce and thus cannot spread the plasmodium parasite throughout the population. This is strategic because it will drastically reduce the mosquito population, mathematically reducing the risk of contracting malaria.
The other approach is alteration. This is where the drives are designed to make mosquitoes resistant to the plasmodium parasite, thus not getting infected at all. These are strategic because they eliminate the spread of plasmodium, rather than just reduce the mosquito population.
Let’s contrast standard inheritance and gene drive inheritance to recap. In standard inheritance, offsprings get one copy of each parent’s chromosome, leading to a 50% chance of inheriting the mutation. With gene drives, the gene is present on both of the inherited chromosomes, leading to a 100% chance of inheritance. As you can see, gene drive inheritance is far more efficient to spread a mutation across a population.
The World Health Organization has outlined a path of progression for CRISPR malaria treatment. The first stage is the laboratory. This is where gene drives research at the present.
The second stage is field testing. This is important to ensure gene drives actually work outside of the lab setting. Researchers report that they should be ready for this in the next one to five years.
Phase three is coordinated releases. During this phase, the gene drive mosquitoes are released and observed while scientists make changes if needed.
In order to do this, there are many steps to be taken. To begin with, countries with high malaria prevalence should develop insectaries. Tests should also be simulated with non-gene drive mosquitoes before gene drive mosquitoes. This is to accurately get an understanding of the process.
The exciting future of gene drives.
CRISPR gene drives are a promising cure for malaria reduction. With ongoing research and more on the way, we should be optimistic about the future of CRISPR gene drives as a viable measure for malaria prevention.