Acute malaria manifests during the erythrocytic phase of infection. Symptoms in immunologically naive hosts are initially nonspecific and include fevers, rigors, headache, myalgias, lethargy, abdominal pain, and vomiting. In children, symptoms may present acutely and in a rapidly progressive fashion with seizures, hypoglycemia, severe anemia, and hypotension. The physical examination may reveal hepatospleno-megaly, but despite hemolysis, jaundice is not frequently observed. Cerebral malaria, characterized by unarousable coma caused by sludging of parasitized erythrocytes in cerebral capillaries, is a severe complication of falciparum malaria and is fatal if untreated.
In contrast, partially immune hosts (i.e., patients living in malaria-endemic areas) may have asymptomatic circulating parasitemia. Others may have intermittent fevers without localizing signs or severe disease. In these cases, interpretation of positive smears must be made with caution as parasitemia may not indicate clinical disease (1,3). Tests are not available to identify reinfection of partially immune patients with new strains to which the host is not immune.
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