Identification and characterization of a generic DNA probe capable of detecting plasmodial infections in blood.

DNA-based detection systems are being rapidly adapted for diagnostic technologies. The currently available non-radioactive DNA techniques for malaria detection are primarily based on probes which are species-specific. The major requirement of a cross-species (generic) diagnostics is the identification of an universal probe which is long enough to be used in either PCR amplification or solid state capture of the hybrids, the two principal techniques currently used in the field of non-radioactive DNA detection. This paper describes a DNA sequence (pARC 178), originally obtained from P. falciparum genomic library, which is also present in other malarial species. Southern-blot analysis indicates that this sequence is derived from a repetitive DNA element. This DNA fragment encodes for a small RNA species of approximately 120 bases. PCR primers based on this sequence amplifies the expected size (157 bp) product from the genomic DNA isolated from P. falciparum, P. vivax, P. berghei, P. yoelii, P. vinckei and P. chabaudi thus confirming its generic nature. The utility of this probe is further demonstrated by its capability in successfully detecting P. falciparum and P. vivax infections in clinical samples when used in a PCR assay.