Science Advances: Breeding mosquitoes that can't transmit malaria

Scientists genetically engineered mosquitoes to slow the growth of malaria-causing parasites in their guts, preventing malaria from spreading to humans
.

This genetic modification allows mosquitoes to produce compounds in their guts that inhibit the growth of parasites, meaning they are less likely to reach the mosquito's salivary glands, which are passed
on by bite before the mosquito dies.

So far, the technique has been shown to greatly reduce the likelihood of malaria spreading in laboratory settings, but if it proves safe and effective in real-world settings, it could provide a powerful new tool
to help eliminate malaria.

The innovation, carried out by researchers from Imperial College London's Propagation: Zero, team can be combined with existing "gene drive" technology to spread GMOs and drastically reduce malaria transmission
.

Bill and collaborators at the Melinda Gates Foundation Institute for Disease Modeling have also developed a model that, for the first time, can assess the impact of
using such modifications in a variety of African settings.

Postpone the development of the disease

Malaria remains one of the most devastating diseases in the world, putting about half of the world's population at risk
.

Co-lead author of the study, Dr Tibebu Habtewold, from the Department of Life Sciences at Imperial College London, said: "Progress in malaria control has stalled since 2015
.

The disease is transmitted from person to person after a female mosquito bites someone infected with the
malaria parasite.

However, only about 10 percent of mosquitoes live long enough for the parasite to develop to be contagious
.

The team genetically engineered the main malaria-carrying mosquito species in sub-Saharan Africa: Anopheles gambia mosquitoes.

This delays the next parasite stage in reaching the mosquito's salivary glands by a few days, and at this time, most mosquitoes in nature are expected to die
.

Co-first author of the study, Astrid Holman, from Imperial College's Department of Life Sciences, said: "For years, we have been trying to create mosquitoes that cannot be infected by parasites, or mosquitoes that can use their immune systems to clear all parasites, but without success
.

Propagated modifications

To use genetic modification to prevent the spread of malaria in the real world, it needs to be transmitted from lab-grown mosquitoes to wild mosquitoes
.

A gene drive is an additional genetic trick that can be added to mosquitoes to give priority to genetic modification of anti-parasite, allowing it to spread
more widely in any natural population.

Since this strategy is a new one, very careful planning is required before any field trials are conducted to minimize risk
.

They can then test anti-parasite modifications first, adding them only after the gene drive
has proven to be effective.

Co-first author Dr Nikolai Windbichler, from the Department of Life Sciences at Imperial College London, said: "Our goal now is to test whether this modification can stop the spread of malaria, not only using parasites that we have grown in the laboratory, but also by infecting human parasites
.
" If this proves to be correct, then we will be ready to conduct field trials
in the next two to three years.
”

This is another weapon in the arsenal

Together with partners in Tanzania, the team has set up a facility to produce and process genetically modified mosquitoes and conduct some initial testing
.
These measures include the collection of parasites from locally infected schoolchildren to ensure that GM vaccines are able to combat parasites that spread in relevant communities
.

They are also fully assessing the risk of any genetically modified mosquitoes that may be released, taking into account any potential dangers and ensuring that they have the support
of the local community.
But they hope their intervention will eventually help eradicate malaria
.

Professor George Christophides, from Imperial College's Department of Life Sciences, said: "History tells us that there is no panacea for malaria control, so we have to use all the weapons we have and make more weapons
.
" Gene drives are a very powerful weapon that, combined with drugs, vaccines and mosquito control, can help stop the spread of malaria and save human lives
.
”

The work was funded
by the Bill & Melinda Gates Foundation.

essay

Gene drive mosquitoes can aid malaria elimination by retarding Plasmodium sporogonic development