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Mosquitoes unable to spread malaria engineered by scientists - ScienceDaily

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Scientists engineered mosquitoes to slow the growth of the parasite that causes malaria in the gut, preventing malaria from spreading to humans.

Through genetic modification, mosquitoes produce compounds in their intestines that inhibit the growth of parasites. That means the parasite is less likely to reach the mosquito’s salivary glands and infect the insect with a single bite before it dies.

So far, the technology has been shown to dramatically reduce the chances of malaria spreading in the laboratory, but if proven to be safe and effective in the real setting, it could eradicate malaria. We may be able to provide powerful new tools to help

The innovation, by researchers from the Transmission: Zero team at Imperial College London, is designed to combine with existing ‘gene-driven’ technology to spread the modification and significantly reduce malaria transmission. The team is eyeing field trials, but will thoroughly test the safety of the new modification before combining it with the gene drive for real testing.

Collaborators at the Institute for Disease Modeling at the Bill and Melinda Gates Foundation have also developed a model that, for the first time, can assess the impact of such changes when used in a variety of African settings. They found that a modification developed by the Transmission:Zero team could be a powerful tool for reducing malaria cases even in areas of high transmission.

The results of our modified lab techniques and modeling are available today at scientific progress.

delay the development of parasites

Malaria remains one of the world’s deadliest diseases, with about half of the world’s population at risk. In 2021 alone, 241 million people were infected and 627,000 died. Most of them are children under the age of five in sub-Saharan Africa.

Dr. Tibeb Habtewold of Imperial’s Life Sciences Division, co-first author of the study, said: Treatments, and funding, have plateaued. We need to develop innovative new tools.”

The disease is transmitted between people after a female mosquito bites a person infected with the malaria parasite. The parasite then develops to the next stage in the mosquito’s gut, moving to the salivary glands where it is ready to infect the next mosquito bite.

However, only about 10% of mosquitoes live long enough for the parasite to become infective. The team aimed to increase the odds even further by extending the time it takes for the parasite to grow in the gut.

The Transmission: Zero team genetically engineered mosquitoes, a major malaria-carrying species in sub-Saharan Africa. Anopheles gambiaeThey were able to make mosquitoes produce two molecules called antimicrobial peptides in their intestines when they ingest blood. impede

This causes a delay of several days before the next stage of the parasite reaches the mosquito’s salivary glands, by which time most mosquitoes in nature are expected to be dead. Peptides work by interfering with the parasite’s energy metabolism. This also has some effect on mosquitoes, shortening their life span and further reducing their ability to infect parasites.

Astrid Holman of Imperial’s Life Sciences Division, co-first author of the study, said: Delaying parasite development inside mosquitoes is a conceptual shift that has opened up more opportunities for stopping the transmission of malaria from mosquitoes to humans. “

Diffusion of Modifications

Using genetic modification to prevent the spread of malaria into the real world would require spreading it from lab-reared mosquitoes to wild mosquitoes. Normal interbreeding spreads it to some extent, but changes have an “adaptive cost” in the form of shortened lifespans, so they can be quickly eliminated thanks to natural selection.

Gene drives are additional genetic tricks that can be added to mosquitoes, causing them to preferentially inherit antiparasitic genetic modifications and spread them more widely among natural populations.

Since this strategy is so new, it requires very careful planning to minimize risk before field trials. As such, the Transmission:Zero team is creating two separate but compatible strains of modified mosquitoes.

We then test the antiparasitic modifications alone first, and then add the gene drive when shown to be effective.

Dr. Nicolai Windbichler, co-lead author of Imperial’s Life Sciences Division, said: If this proves true, we will be ready to bring this to field trials in the next couple of years. “

another weapon in the arsenal

The team, along with partners in Tanzania, have set up facilities to produce and process genetically modified mosquitoes and conduct some initial tests. These include collecting parasites from locally infected schoolchildren to ensure that the modification works against circulating parasites in relevant communities.

They also do a full risk assessment of the potential release of modified mosquitoes, taking into account the potential hazards and ensuring buy-in from the local community. , hoping their interventions will eventually help eradicate malaria.

Professor George Christofides, co-lead author, Department of Life Sciences, Imperial University, said: Gene drives are one of the most powerful weapons in the world, and combined with drugs, vaccines and mosquito control, they can stop the spread of malaria and save lives. “

This work was funded by the Bill and Melinda Gates Foundation.