Species-specific 18S rRNA gene amplification for the detection of P. falciparum and P. vivax malaria parasites.

Based on the sequence diversity of the Plasmodium 18S ribosomal RNA (rRNA), we designed oligonucleotide primers for polymerase chain reaction (PCR) to yield different size fragments for P. falciparum and P. vivax. The primers for the PCR procedure were chosen such that the 5' primer was Plasmodium-conserved while the 3' primers were species-specific. Using primer cocktails and cloned plasmid DNAs containing the 18S rRNA genes or parasite genomic DNA as targets, we show that the PCR procedure yields 1.4-kb and 0.5-kb DNA fragments for P. falciparum and P. vivax, respectively. Limited field testing of this procedure demonstrated the utility of a ribosomal gene based species-specific malaria diagnosis.