Serum copper concentration was measured in 80 adult patients (40 males and females each; age range: 18-40 yr) presenting with acute, uncomplicated falciparum malaria infection and a control group of 20 age-matched, healthy individuals. The mean serum copper concentration was 109.0 +/- 40.0 microg/dL in healthy individuals. Both male and female patients were found to have a significantly decreased serum copper concentration (p < 0.05). In the male patients, the mean serum copper concentration decreased by 33.95%, whereas it dropped by 38.53% in their female counterparts. A compromised enzymatic antioxidant defense capability, particularly superoxide dismutase (SOD) activity, has been reported in patients with falciparum malaria infection. Because SOD activity is dependent on copper, the ineffective SOD activity can be related to the decrease in the concentration of copper during the infection. Low serum copper can also contribute to the ineffective immune response of the host to the antigenic challenge of the falciparum parasite because copper is also important for normal immune function.