Sensitive detection of Plasmodium falciparum in blood and mosquito by DNA amplification

By means of enzymatic amplification of Plasmodium falciparum DNA using the polymerase chain reaction (PCR), we have been able to detect as little as 20 parasites in 20 ml infected human blood based on the visualization of a 206 bp fragment in ethidium bromide-stained agarose gel. Comparison, through microscopic examination of 2030 blood samples collected from various endemic areas in Thailand, indicates that the PCR-based detection system is 96% specific and 81% sensitive, with a disagreement of 6.6%. The same protocol can be applied to detect a minimum of 10 sporozoites or a single oocyst dissected from P. falciparum-infected mosquito.