Scientists develop a new CRISPR-based approach to suppress female malaria-spreading mosquitoes

What is Malaria?

Malaria is a life-threatening infectious disease caused by the transmission of parasitic protozoans of the Plasmodium genus. It is primarily transmitted to humans through the bites of infected female Anopheles mosquitoes. While malaria can be found in various parts of the world, it is most prevalent in tropical and subtropical regions, particularly in Sub-Saharan Africa.

The symptoms of malaria typically appear within 10 to 15 days after being bitten by an infected mosquito. The most common symptoms include recurrent episodes of high fever, chills, sweats, headaches, body aches, fatigue, nausea, and vomiting. In severe cases, malaria can lead to complications such as organ failure, severe anemia, cerebral malaria (affecting the brain), and even death, particularly in young children and pregnant women.

Every year, nearly half a million people die due to malaria 😢.

Suppressing female mosquitoes to suppress malaria

A promising strategy in the battle against malaria involves suppressing the population of female mosquitoes, which are the primary vectors responsible for transmitting the disease. By reducing the number of female mosquitoes, the transmission of malaria can be significantly hindered, potentially leading to a decline in the incidence of the disease.

Controlling the female mosquito population is crucial because only female mosquitoes bite humans and transmit the malaria-causing parasites. Male mosquitoes, on the other hand, primarily feed on plant nectar and do not contribute to disease transmission. Therefore, targeting females specifically allows for a more focused and effective approach in combating malaria.

Ifegenia - A CRISPR-based female mosquito disruptor

One approach to suppressing the female mosquito population is through genetic manipulation. Researchers have been exploring innovative techniques, such as the use of genetic engineering and gene-editing technologies like CRISPR, to disrupt genes that are essential for female mosquito development and reproduction. By introducing mutations or interfering with specific genes, scientists aim to create mosquitoes that produce non-viable female offspring or render females unable to reproduce.

Recently, researchers developed a new method called Ifegenia to control the spread of malaria 1.

The Ifegenia system is based on a two-part method that utilizes the CRISPR gene-editing technology. The researchers disrupted a gene called femaleless (fle) which is essential for female mosquito development. By doing so, they achieved a complete separation of the sexes, as only male mosquitoes were able to survive and reproduce. This resulted in a heritable trait where the female offspring of Ifegenia mosquitoes were not viable and died before reaching adulthood.

Importantly, the researchers demonstrated that the Ifegenia males remained reproductively capable and could pass on the fle mutations and the CRISPR machinery to subsequent generations. This allowed for the sustained suppression of the female mosquito population over time.

To test how this system would actually work in the field, the researchers used mathematical modeling to simulate the effects of Ifegenia males when released in to the population. The results showed that this approach could effectively suppress and potentially eliminate the female mosquito population while being manageable, contained, and safe.

Summary

The Ifegenia system offers a promising strategy for controlling malaria by genetically suppressing the population of female mosquitoes, which are the primary disease vectors. By using CRISPR technology to disrupt a female-specific gene, the researchers achieved successful sex separation and demonstrated that the population suppression effect could be maintained across generations. The approach shows potential for being an effective, controlled, and safe method to combat malaria transmission.