Malaria

Alternative names:

Quartan malaria; falciparum malaria; biduoterian fever; blackwater fever; tertian malaria; plasmodium

Definition:

A parasitic disease characterized by fever, chills, and anemia.

Causes, incidence, and risk factors:

Malaria is caused by a parasite that is transmitted from one human to another by the bite of infected Anopheles mosquitoes. In humans, the parasites (called sporozoites) migrate to the liver where they mature and release another form, the merozoites. These enter the bloodstream and infect the red blood cells. The parasites multiply inside the red blood cells, which then rupture within 48 to 72 hours, infecting more red blood cells. The symptoms occur in cycles of 48 to 72 hours. The majority of symptoms are caused by the massive release of merozoites into the bloodstream, the anemia caused by the destruction of the red blood cells, and the problems caused by large amounts of free hemoglobin released into the circulation after red blood cells rupture.

Malaria can also be transmitted congenitally (from a mother to her unborn baby) and by blood transfusions. Malaria can be carried by mosquitoes in temperate climates, but the parasite disappears over the winter.

The disease is a major health problem in much of the tropics and subtropics. More than 200 million people in the world have malaria. It presents the greatest disease hazard for travelers to warm climates. In some areas of the world, mosquitoes that carry malaria have developed resistance to insecticides, while the parasites have developed resistance to antibiotics. This has led to difficulty in controlling both the rate of infection and spread of this disease. Falciparum malaria, one of four different types, affects a greater proportion of the red blood cells than the other types and is much more serious. It can be fatal within a few hours of the first symptoms.

Update Date: 02/09/00
Updated by: J. Gordon Lambert, MD, Associate Medical Director, Utah Health Informatics and adam.com editorial