Malaria. A boy in a Tanzanian hospital receives a blood transfusion for severe malaria, while his parents prepare to feed him. Severe malaria is caused by the single-celled parasite Plasmodium falciparum, which is transmitted to humans by the bite of an infected mosquito. The parasites multiply in blood cells, causing bouts of fever when they burst out. Symptoms include anaemia, jaundice, kidney failure and, if the brain is affected, convulsions and coma. Emergency treatment includes blood transfusions and antimalarial drugs, although resistance to these is a growing problem. Malaria kills around one million children in Africa every year.