Eradicating Malaria With Gene-Editing
Mosquitoes are not just pests but one of the deadliest animals that carry a lethal disease called malaria. The WHO estimates that there were 219 million cases of malaria in 87 countries and 435000 deaths caused by malaria in just 2017. This statistic is almost equivalent to 3% of the world’s population every year and it has occurred in spite of a global spending around $3.1 billion on advancements.
Malaria is caused by a parasite called Plasmodium falciparum. The mosquitos infected with this parasite can spread them to humans with a small bite. Only female mosquitoes with a specific genus can transmit this disease as they need to obtain blood needed to nurture their eggs. Once the parasite is inside a human it can cause symptoms ranging from anemia to death.
Current challenges to dealing with malaria
The current solution for malaria involves antibiotics and antimalarials. However, like many antibiotics, there is widespread overuse of this drug caused by the distribution of falsely labelled antimalarials and huge cases of misdiagnosis. These factors have resulted in strains of Plasmodium Falciparum which are resistant to nearly all antimalarials currently in use. This means that antibiotics, which were thought of as a solution for malaria this long, are slowly becoming obsolete.
In 2017, Africa was home to 92% of malaria cases and 93% of malaria deaths as stated by the WHO. This makes the problem even harder to solve because of the lack of infrastructure and access to healthcare in many regions in Africa.
But, what if we could go beyond the problem of resistance and location by a huge global solution? A solution that can help us globally remove an entire species of Anopheles mosquitos. This is the concept on which a new solution has recently been found — Gene Editing.
With the right move, gene editing could potentially be a breakthrough saving millions of lives in the world but if a wrong move is made it could pose a tragic burden on the Earth’s ecosystem.
What is Gene Editing?
DNA is a code in the body that defines an individual organism. DNA stores information using 4 alphabets: A, T, G and C. DNA is stored in a double helix formation with a simple rule that A pairs with T and G pairs with C. This information shapes uniques individuals as well as species. These genes don’t only decide how an organism looks but also affect the risk of diseases.
Changing genes in living beings has been very difficult. However, with the rise of the CRISPR method, there is a promise to exponentially break barriers in this field. The CRISPR method is based on a system used by bacteria to protect them from viruses. This method uses a protein called CAS9 that uses two tiny molecular scissors to cut DNA. Specific target sequences of DNA can be identified by a guide RNA and cut using the CAS9 protein.
Modifying the guide RNA means that you can target any DNA sequence in an organism and completely change the function it affects.
Gene Editing to solve Malaria
Malaria starts with a bite from a female Anopheles mosquito which releases plasmodium into the blood. There are trillions of mosquitos and a single one lay up to 300 eggs at a time. This makes them practically impossible to eradicate. But maybe we don’t need to eradicate them all?
We could just change the types which transmitting diseases than trying to tackle the entire population of mosquitos.
Using genetic engineering scientists have successfully created a strain of mosquitos that are immune to the parasite. Other scientists have also worked on altering genes that produce a defect in the mouth so it is no longer able to bite humans to transmit the diseases.
However, just the change in a gene is not the full solution. Genes are made of 2 chromosomes one from each parent so changing the gene means only half the offspring are born with the altered features. It would not make a difference in a huge population of mosquitos.
That is why scientists have introduced a new method called gene drive that makes the genes dominant so it is impossible for it to not be expressed in the offsprings. If the altered gene as part of the gene drive is received from the mother then the normal sequence received from the father is deleted. The gene drive copies itself so there is two sets of sequences to form a gene.
This could completely change malaria for good. If enough mosquitos are released into the wild we have the power to fully eradicate malaria!
Gene drives have been tested already in the Cayman Islands resulting in a 62% decrease in mosquitos carrying dangerous diseases.
Problems with using a gene drive
We have moved past the stage to bringing this concept alive. Scientists have the mosquitos in their labs but it is a question of whether it should be released or not?
Humans have never had the power to change the genetic code and control evolution on this scale. Once the mosquitos have been modified there is no going back. So we need to be very careful before releasing this globally.
The UN has had many calls to ban gene drives because if the gene spreads to other insects like bees then it poses a huge risk to the food production as defects may lead to no pollination by the bees. If the gene drive is released it might be at the risk of a global drought whose consequences will be irreversible.
“To be or not to be?”
At the same time, there are benefits that could positively affect the world weighing in as well. If Mosquitos can’t spread diseases we are not just stopping malaria but also Zika and Dengue fever(which are diseases transmitted by mosquitos.) This could be the difference between life and death of atleast a million people.
This gene drive is a powerful technology. But we must harness the power with ethical responsibility. We need to decide if it is ethical not to use this when so many deaths are happening or to use it and risk global consequences?
TL;DR
- Malaria is a deadly disease spread by a specific type of mosquito
- Current solutions for Malaria don’t work because of anti-malarial resistance
- Gene editing uses CRISPR and CAS9 to edit the genes of mosquitos to alter their features. Changing the mouth of a mosquito so they can no longer bite could solve the problem of Malaria.
- There could be negative consequences if it spreads to other species including global droughts.
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