Malaria vaccine 'closer'

Malaria is passed by mosquitos

A breakthrough in understanding what causes malaria may speed up development of a vaccine, say researchers.

Scientists found that concentrations of the malaria parasite were higher in children with severe illness and believe this may help them to fight the disease.

This is another step in a very complicated process

Professor Brian Greenwood, London School of Hygiene and Tropical Medicine

Clumps of the malaria parasite - Plasmodium falciparum - can form in infected red blood cells and the scientists are now trying to establish if this clumping behaviour directly causes severe disease and to pinpoint the part of the parasite responsible.

Dr David Roberts, at the National Blood Service, made the discovery after studying specimens of the parasite taken from patients in Africa.

He found that the clumps, known as autoagglutination of blood cells, occurred in over 70% of children with severe malaria, but in less than half of those with mild disease.

And the number of cells in the clumps was far higher in children with the most serious illness.

Deaths

There are about 1m deaths from malaria world-wide each year and up to 500m people become ill with the disease.

Most deaths are in children under the age of five. It is estimated that between 200 and 300 children an hour die of malaria.

Dr Roberts said: "We know there is a family of proteins on the surface of red blood cells which can cause parasites to stick to blood vessels and probably cause clumping of infected cells as well.

"Our next challenge is to identify exactly which of these parasite molecules are responsible for clumping of infected cells. This will help enormously to narrow down the search for an effective vaccine."

Professor Brian Greenwood at the London School of Hygiene and Tropical Medicine said any vaccine developed from the discovery would not stop infection, it would simply prevent the full blown development of the disease and its symptoms.

He added: "This is another step in a very complicated process. It is such a difficult process we are having to explore every avenue in the hope a vaccination is found in the end."