Patients with malaria have symptoms that cycle, writes Jake Buehler for ScienceNews. But the regular return of fever and chills every 24 to 72 hours is not dictated by the internal clock of the human host. Jake reports that the unicellular Plasmodium parasites seem to have their own circadian clock driving synchronous reproduction. @ScienceNews @buehlersciwri and jakebuehler.com image: CDC