Modelling Malaria

Every year, hundreds of millions of people contract malaria; this is a parasitic infection spread by mosquitoes. The parasite does two things when it grows in the body: either it clones itself to make millions more malaria parasites in that infected individual, and makes them sicker in the process; or, it produces a different form of the parasite that's sexually active and specialised to infect mosquitoes so it can spread to another human. And this week scientists in Edinburgh have discovered that malaria bases the decision on whether to boost its numbers in an infected person, or to try to spread to other individuals, by counting its own population. Understanding how this works, they think, might provide us with new ways to tackle the problem. Petra Schneider told Chris Smith what she's found...