Malaria Malaria is one of the oldest and most frequently occurring infectious diseases in humans. The malaria parasite, transmitted through the bite of an infected female mosquito, disables hundreds of millions of people worldwide each year. However, several challenges must be overcome. For one thing, Plasmodium falciparum , the most lethal form of the infectious parasite, has developed resistance to many of the antimalarial drugs currently available. And social and political factors, particularly in Africa, further challenge efforts to institute effective control measures.
Malaria is a disease caused by a single-celled parasite called Plasmodium .
The parasite reproduces and matures in stages inside humans, using different tissues to support its development. When an infected mosquito bites a human host, the parasite moves from the insect's saliva into the host's blood. Parasitic sporozoites head immediately to the liver, where they hide inside liver cells. There they reproduce and mature into merozoites, the form of the parasite that infects red blood cells or erythrocytes. Attacks can last as long as 36 hours and may kill the patient.