Video report by ITV News Science Editor Tom Clarke
A genetically modified fungus that kills mosquitoes spreading malaria could provide a breakthrough in the fight against the disease, according to scientists.
Trials in Burkina Faso found that a fungus, modified so that it produces spider toxin, quickly killed large numbers of mosquitoes that carry malaria.
It also revealed that the mosquito populations collapsed by 99% within 45 days, according to the study published in the journal Science.
The researchers have said their aim is not to make the insects extinct but to help stop the spread of malaria.
The toxin, an insecticide called Hybrid, comes from the venom of the Australian Blue Mountains funnel-web spider.
The disease, which is spread when female mosquitoes drink blood, kills more than 400,000 people per year.
"No transgenic malaria control has come this far down the road toward actual field testing," Brian Lovett, from the University of Maryland, said.
"This paper marks a big step and sets a precedent for this and other transgenic methods to move forward."
The fungus was then tested in a simulated village setting in Burkina Faso, in West Africa - a structure called the MosquitoSphere - which included plants, huts, small pools of water and a food source for mosquitoes.
Mr Lovett said: "Simply applying the transgenic fungus to a sheet that we hung on a wall in our study area caused the mosquito populations to crash within 45 days.
"And it is as effective at killing insecticide-resistant mosquitoes as non-resistant ones."
The fungus was found to be safe for other insects and honeybees.