New front opened in war on malaria

A potentially revolutionary weapon in the fight against malaria has been developed by scientists who for the first time have found a way of killing the parasite within the mosquitoes that spread the disease.

Most of the recent effort against malaria has concentrated on treating the disease in humans or controlling mosquito populations but now scientists have discovered that parts of the insect's immune system can destroy the malaria parasite.

The findings open the prospect of a third front against the disease with the development of a chemical spray that blocks the development of malaria inside the insect, thereby preventing transmission to man.

Malaria - which kills up to 2 million children a year - has developed a strong resistance to anti-malarial drugs, says Professor Fotis Kafatos of the European Molecular Biology Laboratory in Heidelberg, Germany, who led the study.

"These studies are the first to show the power of the mosquito's immune system and give us some very real options for fighting the disease in the insect before it even has a chance to be passed to a human," Professor Kafatos said.

"There is no single 'magic bullet' for controlling this ancient scourge of humanity, but we want to exploit this new lead to contribute to the defeat of malaria."

Scientists have known for many years that some mosquitoes, even within the same species, are possible carriers of malaria while others do not transmit the disease. The reason, however, was not known.

The scientists found a set of critical components within the mosquito's immune system that directly affect the ability of the malaria parasite to survive in the insect's gut and blood system.

Two of the components - proteins produced by the insect's immune system genes - block the development of the malaria parasite, while the other two appear to allow the parasite to develop.

Mike Osta, a member of the team, said that it might be possible to breed genetically engineered mosquitoes that had appropriate amounts of these proteins so that the parasite was killed. Releasing these insects into the wild could result in malaria being curbed if these mosquitoes outlived their malaria-carrying cousins.

Another approach could be to develop chemical sprays which directly influence the production of the four proteins so that malaria-carrying mosquitoes in the wild could be rendered harmless. "We envisage that this should give us new ways of defeating malaria," Dr Osta said. "It's a war on several fronts."

How it works

* Mosquitoes carry the malaria parasite in their guts and blood.

* Scientists have found that two proteins in the mosquito's own immune system kill the parasite, while two others nourish it.

* Researchers could therefore produce a genetically engineered mosquito with more parasite-killing proteins or a chemical spray designed to have the same effect.

- INDEPENDENT