- The team was initially looking for ways to sterilise female mosquitos that had developed insecticide resistance, to prevent resistance spreading.
- But when they found that the compounds they were testing also affected the malaria parasites inside the mosquitos, they shifted their focus.
For years, insecticide-soaked mosquito nets have helped dramatically lower malaria infections, but insecticide resistance has driven a search for alternatives and a new study may have uncovered one option.
The weapon is a familiar one: an anti-malarial drug already used by humans to prevent them contracting the disease, and researchers now envisage using it on netting like insecticides.
Their research shows the drug works on mosquitos, killing the malaria parasite in the insects and preventing it from being transmitted.
It is a potentially important breakthrough in the battle against a disease that killed 435,000 people in 2017, the majority of them children under five in Africa.
In 2017, the number of malaria cases climbed to 219 million, a worrying rise from the previous year and a sign that long-standing progress is being reversed.
The researchers, including Flaminia Catteruccia, a professor of immunology and infectious diseases at Harvard University, found exposing mosquitos to even low doses of an anti-malarial called atovaquone or ATQ caused "full parasite arrest".
"We tested a couple of anti-malarials, and it worked beautifully with ATQ: all parasites were killed!" Catteruccia told AFP by email.
The team was initially looking for ways to sterilise female mosquitos that had developed insecticide resistance, to prevent resistance spreading.
But when they found that the compounds they were testing also affected the malaria parasites inside the mosquitos, they shifted their focus.
"We then thought, if we can attack parasites with non-specific chemicals, why don't we try to kill them more effectively with anti-malarials," Catteruccia said.
They settled on ATQ because like insecticides it can penetrate the "skin" of mosquitos when they land on nets.
The team, whose research was published Thursday in the Nature journal, tried to simulate the conditions in which insects land on nets.
They fed two groups of mosquitos with malaria-infected blood and then exposed one group to surfaces coated with ATQ.
Just six minutes of contact with the surface -- around the time the insects would usually spend on a net trying to land a bite -- wiped out the malaria parasites in the mosquitos.