A HIGHLY SENSITIVE, RAPID, AND SIMPLE POLYMERASE CHAIN REACTION-BASEDMETHOD TO DETECT HUMAN MALARIA (PLASMODIUM-FALCIPARIUM AND PLASMODIUM-VIVAX) IN BLOOD-SAMPLES

A highly sensitive, rapid and simple method to detect human malaria in blood samples was developed. Malaria parasite DNA in blood from a fin gerprick was directly amplified by the polymerase chain reaction (PCR) using two sets of primers to yield a 206-basepair (bp) product for Pl asmodium falciparum and a 183-bp product for P. vivax Both were easily visualized in an ethidium bromide-stained agarose gel, allowing ident ification of the two human malaria species in a single amplification r eaction. As little as a one P. falciparum and/or P. vivax parasite per microliter of blood was detectable by this method, a sensitivity supe rior to that of thick blood film microscopy. The total time required f or diagnosis of 48 blood samples, starting from fingerprick blood coll ection, was approximately 4 hr. When compared with microscopic examina tion by an expert microscopist, results showed a sensitivity of 89% fo r P. falciparum and 91% for P. vivax and an overall specificity of 94% . Six infected blood samples classified by microscopy as single specie s were diagnosed by the PCR method as being mixed P. falciparum and P. vivax infections. The high sensitivity, rapidity, and simplicity of t he method should make it attractive for a large-scale epidemiology stu dy, follow-up of drug treatment, and immunization trials.