malaria /məler″ē·ə/ [It, mal, bad, aria, air] , a severe infectious illness caused by one or more of at least four species of the protozoan genus Plasmodium. The disease is transmitted from human to human by a bite from an infected Anopheles mosquito. Malarial infection can also be spread by blood transfusion from an infected patient or by the use of a contaminated or an infected hypodermic needle. Although the endemic disease is limited largely to tropical areas of South and Central America, Africa, and Asia, a number of new cases are introduced into the United States by refugees, military personnel, and travelers returning from malarial areas. See also double quartan fever. ▪ OBSERVATIONS: Malaria is characterized by chills and fever, anemia, an enlarged spleen, myalgia, arthralgia, weakness, and vomiting. Splenomegaly, anemia, thrombocytopenia, hypoglycemia, pulmonary or renal dysfunction, and neurosis may also occur. P. falciparum, P. ovale, or P. vivax parasites penetrate the erythrocytes of the human host, where they mature, reproduce, and burst out periodically. Malarial paroxysms occur at regular intervals, coinciding with the development of a new generation of parasites in the body. Because the life cycle of the infecting parasite varies according to species, the clinical patterns of chills and fever vary, as do the course and severity of the disease. Bouts of malaria usually last from 1 to 4 weeks, with attacks occurring less frequently as the disease progresses. Relapse is common, and the disease can persist for years. ▪ INTERVENTIONS: Malaria prophylaxis involves the administration of chloroquine, tetracycline, doxycycline, or mefloquine. Treatment for active malaria includes the administration of chloroquine, quinine, tetracycline, clindamycin, doxycycline, mefloquine, primaquine, sulfonamides, or pyrimethamine.
