According to a Wellcome Trust study in Malawian children, recurrent episodes of malaria cause chronic inflammation in blood vessels that might predispose to future infections and may increase susceptibility to cardiovascular disease.
The findings could explain the indirect burden of malaria on childhood deaths in areas where the disease is highly prevalent and children experience multiple clinical episodes of malaria in a year.
Malaria is caused by infection with a parasite that starts by infecting the liver and then moves into red blood cells.
The most deadly of the malaria parasites is Plasmodium falciparum because of its ability to cause inflammation in blood vessel walls, making them more sticky so that the infected red blood cells can cling to the sides.
Being able to stick to the blood vessels in vital organs allows the parasite to hide away from the immune system, a process called sequestration.
When it occurs in the brain it causes a more severe form of the disease called cerebral malaria, associated with seizures, coma and sometimes death.
It was thought that the changes in the blood vessel walls that enable the infected red blood cells to stick would resolve quickly once the cells had been cleared; however, the new findings show that inflammation is still present up to one month later.
Researchers from the Malawi-Liverpool-Wellcome Clinical Research Programme at the University of Malawi College of Medicine in Blantyre, Malawi, looked at 190 children with uncomplicated, mild or cerebral malaria compared with healthy children of the same age.
They found that the changes were most pronounced in children with cerebral malaria, with the levels of one inflammatory molecule remaining 22 times higher than in healthy controls one month after the initial infection.
The findings are published in the Journal of Infectious Diseases.