The malaria parasite can ensure it keeps a host body all to itself by preventing further malarial infections, according to international researchers
An expert said the research was "very cool and very interesting", and improved understanding of infection.
The researchers were looking at super-infections, when a patient already infected with malaria is infected with another batch of malaria parasites.
In experiments on mice, researchers showed that parasites in the blood were able to stimulate the production of the hormone hepcidin, which regulates iron levels.
This reduced the level of iron in the liver, preventing other malaria parasites from reproducing in the organ.
Malaria is often accompanied by anaemia, which is treated with iron supplements.
In this study, mice given iron supplements were more susceptible to additional infections.
Dr Drakesmith said: "We may need to look again at the advisability of iron supplementation programmes in malaria-endemic regions, as possible increased risk of infection may need to be weighed against benefits."
Dr Rita Tewari, a malaria researcher at the University of Nottingham, said: "It's very cool and very interesting.
"It tells us a bit more about the mechanism of malaria infection and gives us some sort of tool, this molecule hepcidin, that you can manipulate which can affect infection."