Malaria breakthrough from Australia

Scientists in Australia have made a breakthrough discovery about how the malaria parasite makes red blood cells too sticky and rigid for the the immune system to deal with that could one day lead to effective treatment against a devastating disease that infects and debilitates 600 million people and kills nearly 3 million every year, with children and pregnant women being the most affected.

The study, published in Cell, was led by Alan Cowman, at the Walter and Eliza Hall Institute (WEHI) of Medical Research in Melbourne, Australia, who collaborated with centres around the world.

Plasmodium falciparum accounts for 80% of human malarial infections and has the highest rates of complications and deaths. It is spread by Anopheles mosquitoes and is prevalent in sub-Saharan Africa.

The parasite is injected into the human bloodstream via bites from an infected mosquito. Once in the bloodstream it sets about hijacking red blood cells and turning them into "sticky sacks" housing up to 32 new daughter parasites. The sticky cells adhere to blood vessel walls, which stops them being transported to the spleen where the immune system would be able to destroy them.

Using a large scale gene knockout strategy, Cowman and colleagues found 8 genes that encode proteins that help to transport the parasite's adhesion factor PfEMP1 to the surface of infected red blood cells, where "sticky knobs" act like platforms that anchor the PfEMP1.

One of the exciting features of the discovery is that researchers found that by removing one of the proteins they could almost completely disrupt the parasite's ability to make the hijacked red cell stick to blood vessel walls.

They concluded that the 8 proteins collectively function as a pathogen secretion system, similar to bacteria. These are potential targets for developing treatments against malaria.