Unpleasant though they are, fevers are the body's way of fighting infection. In the case of malaria, however, that defense mechanism may backfire. According to a report published online this week in the Proceedings of the National Academy of Sciences, fevers enable malaria-infected red blood cells to stick to the walls of blood vessels, which can lead to death.

Although malaria is characterized by fever, studies of parasitized red blood cell adherence have always been conducted at the normal human body temperature. Nicholas J. White of Mahidol University in Bangkok and his colleagues thus decided to investigate the behavior of infected cells in blood heated to temperatures typically seen in malaria cases. Using samples obtained from 12 patients suffering from acute malaria infections, the team found that the stickiness of the parasitized blood cells increased upon heating. At normal body temperatures, in contrast, the blood cells did not exhibit this adherence. Additional findings indicate that the heat-induced stickiness may arise from an increase in levels of a red blood cell surface protein known as PfEMP-1.

The results offer new insight into why malaria patients often deteriorate significantly at the fever stage. They also suggest that, contrary to one popular school of thought, which holds that quelling the fever slows the body's ability to clear the parasite, fever reduction may in fact stymie disease progression and enhance antimalarial drugs' ability to block parasite development.