Genetically Engineered Mosquitoes Prevented the Growth of Malaria-causing Parasites in Their Gut

Scientists have created mosquitoes that inhibit the development of malaria-causing parasites in their stomachs, therefore decreasing disease transmission to people.

Mosquitoes that can't spread malaria

(Photo : Syed Ali/Unsplash)

The genetic change allows mosquitoes to create substances in their intestines that inhibit parasite development, making parasites less likely to reach the mosquitoes' salivary glands and be transmitted in a bite before the insects die, as per ScienceDaily.

The Transmission: Zero team at Imperial College London developed the breakthrough so that it may be used with current "gene drive" technologies to distribute the alteration and substantially reduce malaria transmission.

The team is planning field experiments, but first, they will rigorously verify the new modification's safety before merging it with a gene drive for real-world testing.

Collaborators from the Bill and Melinda Gates Foundation's Institute for Disease Modeling also created a model that, for the first time, can analyze the impact of such changes in a range of African contexts.

They discovered that the Transmission: Zero team's improvement might be a significant tool for reducing malaria cases even in areas where transmission is high.

The Lethal Malaria

Malaria is one of the world's most lethal illnesses, threatening almost half of the world's population.

In Sub-Saharan Africa alone, it infected 241 million and killed 627,000 people in 2021, largely youngsters under the age of five.

Dr. Tibebu Habtewold, the co-first author of the study from Imperial's Department of Life Sciences, stated that progress in combating malaria has halted since 2015.

Mosquitoes and the parasites they transmit are increasingly resistant to existing interventions like pesticides and medicines, and financing has reached a halt. 

When a female mosquito bites someone infected with the malaria parasite, the sickness spreads between humans.

The parasite then matures in the mosquito's intestines and goes to its salivary glands, ready to infect the next human bitten by the mosquito.

Only around 10% of mosquitos live long enough for the parasite to mature to the point where it is infectious.

The researchers wanted to increase the odds even more by prolonging the time it takes for the parasite to grow in the stomach.

The Transmission: Zero team genetically engineered Anopheles gambiae, the predominant malaria-carrying mosquito species in Sub-Saharan Africa.

They were able to modify the mosquito such that when it consumes blood, it creates two chemicals known as antimicrobial peptides in its stomach.

These peptides, which were first obtained from honeybees and African clawed frogs, inhibit the growth of the malaria parasite.

To apply genetic alteration to reduce malaria transmission in the real world, it must be transferred from lab-bred mosquitos to wild mosquitos.

Normal interbreeding might disseminate it to some extent, but because the change has a "fitness cost" in the form of shorter longevity, natural selection would likely rapidly destroy it.

Gene drive is a genetic technique that may be given to mosquitos to make the anti-parasite genetic mutation preferentially inherited, allowing it to spread more broadly within any natural population.

Because this method is so novel, it would need exceedingly careful preparation before any field testing.

As a result, the Transmission: Zero team is developing two distinct but compatible strains of modified mosquitos: one with the anti-parasite alteration and one with the gene drive.

The team has established a laboratory in Tanzania with partners to create and handle genetically modified mosquitos, as well as conduct preliminary experiments.

Among these are parasites collected from locally affected students to ensure that the alteration works against the parasites prevalent in relevant areas.

They are also thoroughly risk-assessing any prospective releases of modified mosquitoes, taking into consideration any potential risks and ensuring community support.

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Why Should We Invest in Malaria Control?

Malaria control measures have demonstrated a positive return on investment.

While much more needs to be done to eradicate this disease, we have made significant progress thanks to increased global attention, increased funding, and successful partnerships, as per Voices for a Malaria Free Future.

More than a million African children's lives have been saved in the last decade, and more than 40 endemic countries have cut malaria cases or deaths in half in recent years.

We may not only lose the profits we have achieved if we do not continue to invest, but the situation will worsen and cost us considerably more in the future.

Malaria control is increasingly acknowledged as an essential component of national poverty reduction programs for malaria-endemic nations due to the disease's social and economic consequences.

We must continue to take steps to ensure that malaria control investments are well spent and that Long-Lasting Insecticide-Treated Nets (LLINs), Artemisinin-Combination Therapies (ACTs), and other tools become more accessible to vulnerable populations by subsidizing production costs, making drugs more affordable, and lowering or eliminating anti-malarial taxes and tariffs.

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