Detection of Plasmodium vivax by Polymerase Chain Reaction in a Field Study

Abstract

Detection and typing of Plasmodium vivax by the polymerase chain reaction (PCR) was evaluated in a prospective blinded comparative field study in Thailand. PCR amplification of the circum sporozoite (CS) gene was compared with microscopy for the detection of P. vivax in blood samples from 174 Thai Rangers and 50 malaria-free Bangkok residents. For PCR analysis, filter paper specimens collected by finger prick were randomly processed and blindly interpreted for the presence of the CS gene of P. vivax. The VK210 and VK247 CS variants of P. vivax were detected by specific fluorescein or radiolabeled oligoprobes. Autoradiography with ³²P-labeled probes and enhanced chemoluminescent detection with fluorescein-labeled probes identified 91% and 96%, respectively, of 119 microscopically confirmed infections; both systems detected P. vivax by PCR suggests that this method may prove to be a valuable tool for epidemiologic and heterogeneity studies of P. vivax.