Malaria--a red alert.

Imported malaria has been increasing in the United States. Locally acquired cases are reported in drug addicts. Extended incubation periods can be misleading. Pyrexia is the most common manifestation, but it may not follow a regular pattern. A high index of suspicion and examination of peripheral blood smears establish the diagnosis. Chloroquine and primaquine are the drugs of choice for uncomplicated malaria; quinine sulfate is preferred in the treatment of chloroquine-resistant malaria. Malarial prophylaxis should include travelers' education and chemoprophylactic agents such as chloroquine, chloroguanide, pyrimethamine and amodiaquine.