Scientists from Hungary and Portugal have found that inhaling carbon monoxide could be a cheap and simple way of preventing cerebral malaria. Cerebral malaria has a mortality rate of between 25 and 50%. If a person is not treated, they are likely to die within 24 to 72 hours. The World Health Organization believes that cerebral malaria results in over one million deaths annually. The researchers found that the inhaled carbon monoxide helped to prevent the malaria parasite from breaching the barrier of blood around the brain. Cerebral malaria develops when the blood brain barrier is breached. Scientists from the University of Debrecen in Hungary, and the Institute of Molecular Medicine and Gulbenkian Institute of Science in Portugal found that carbon monoxide mimics the action of a natural enzyme that the body releases as a response to infection with the malaria parasite, decreasing the effects of the toxic molecule heme. Red blood cells release heme when they become infected with the malaria parasite.