Malaria undercover

Malaria parasites half kill their liver cell hosts, and then hide out in the shattered remnants, say Angelika Sturm, Volker Heussler (Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany), and colleagues. The disguise allows them to escape from the macrophage-rich liver into the general bloodstream; once there they can invade red blood cells.

This complex bit of subterfuge contrasts with the simple grow-and-burst mechanism that the parasite uses to eventually escape from red blood cells. “People extrapolated from the red blood cell situtation,” says Heussler. “But if hepatocytes would burst, [the parasites] would have to individually find their way through the endothelium to the blood vessels and even then they would not be safe—the [liver's] vessels are packed with macrophages.”

A simple burst was, however, what Heussler first hoped to see in vitro. Instead he saw the infected...