[A preliminary study on detecting Plasmodium falciparum in blood by Plasmodium falciparum DNA probe]

A simple and rapid method for detecting Plasmodium falciparum in human blood was used in this study. The assay is based on DNA-DNA spot hybridization. For this purpose, the total genomic DNA of P. falciparum was isolated and purified from the parasite cultured in vitro. Then the total genomic DNA was used as a probe and labelled with [alpha-32P]-dATP by nick-translation. Twenty-five test samples, ten-microliter lysed infected blood each, were spotted onto dry nitrocellulose paper and hybridized with labelled genomic DNA. After hybridization, the paper was exposed to X-ray film for autoradiography, resulting in an image in places where hybridization occurred. The result shows that the assay appears to be sensitive enough to detect parasitaemia up to 0.0009%. No visible hybridization was detected in normal human blood or human leukocytes. Many samples can be processed simultaneously. This may be applicable to mass survey for detecting P. falciparum in epidemiological study (Fig. 2).