TOKYO: 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 mosquitoes, 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 mosquitoes 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 said by email.

The researchers, whose study was published on Wednesday in the Nature journal, said computer modelling showed their novel approach would “substantially mitigate the global health effects of insecticide resistance” in the fight against malaria.

“We are quite excited that this new idea could really help in the fight against malaria in a manner that is safe for people that sleep under those nets and for the environment,” Catteruccia said.

But the researchers acknowledge that significant work is needed before anti-malarials can be used directly against mosquitoes, and there are risks.

Mosquitoes are unlikely to develop resistance to ATQ because it doesn’t affect their survival or reproduction, but when it comes to the malaria parasites “emergence of resistance is always a risk”, Catteruccia said.

And the path to international acceptance will be long, wrote Janet Hemingway, a professor of vector biology at the Liverpool School of Tropical Medicine.

“Substantial hurdles must be overcome before a product is generated that is recommended and universally accepted by funders, countries and communities for use in control programmes,” she wrote in a review of the research commissioned by Nature.

There are also other factors at play in the growing number of malaria infections, experts say, including a decline in funding for campaigns against the infection and a related drop in the use of insecticide-treated nets.

Published in Dawn, February 28th, 2019